NUREG 1437 Vol 1, Generic Environmental Impact Statement for License Renewal of Nuclear Plants, Main Report

NUREG-1437, Volume 1
Revision 2

Generic Environmental
Impact Statement for License
Renewal of Nuclear Plants
Main Report

Final Report

Office of Nuclear Material Safety and Safeguards

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NUREG-1437, Volume 1
Revision 2

Generic Environmental
Impact Statement for License
Renewal of Nuclear Plants
Main Report
Final Report
Manuscript Completed: August 2024
Date Published: August 2024

Office of Nuclear Material Safety and Safeguards

COVER SHEET
Responsible Agency: U.S. Nuclear Regulatory Commission, Office of Nuclear Material Safety
and Safeguards
Title: Final Generic Environmental Impact Statement for License Renewal of Nuclear Plants
(NUREG-1437) Volumes 1, 2, and 3, Revision 2
For additional information or copies of this Final Generic Environmental Impact Statement for
License Renewal of Nuclear Plants, contact:
Jennifer A. Davis, Senior Environmental Project Manager
Kevin T. Folk, Senior Environmental Project Manager
U.S. Nuclear Regulatory Commission
Office of Nuclear Material Safety and Safeguards
Mail Stop T-4B72
11545 Rockville Pike
Rockville, Maryland 20852
Phone: 1-800-368-5642, extension 3835 or 6944
Email: Jennifer.Davis@nrc.gov or Kevin.Folk@nrc.gov

ABSTRACT
U.S. Nuclear Regulatory Commission (NRC) regulations allow for the renewal of commercial
nuclear power plant operating licenses. There are no specific limitations in the Atomic Energy
Act or the NRC’s regulations restricting the number of times a license may be renewed. To
support license renewal environmental reviews, the NRC published the first Generic
Environmental Impact Statement for License Renewal of Nuclear Plants (LR GEIS) in 1996. Per
NRC regulations, a review and update of the LR GEIS is conducted every 10 years, if
necessary. The proposed action is the renewal of nuclear power plant operating licenses.
Since publication of the 1996 LR GEIS, 59 nuclear power plants (96 reactor units) have
undergone license renewal environmental reviews and have received renewed licenses (either
an initial license renewal [initial LR] or subsequent license renewal [SLR]), the results of which
were published as supplements to the LR GEIS. This revision evaluates the issues and findings
of the 2013 LR GEIS (Revision 1). Lessons learned and knowledge gained from initial LR and
SLR environmental reviews provide an important source of new information for this assessment.
In addition, new research, findings, public comments, changes in applicable laws and
regulations, and other information were considered in evaluating the environmental impacts
associated with license renewal. Additionally, this revision fully considers and evaluates the
environmental impacts of initial LR and one term of SLR.
The purpose of the LR GEIS is to identify and evaluate environmental issues for license renewal
and determine which could result in the same or similar impact at all nuclear power plants or a
specific subset of plants (i.e., generic issues) and which issues could result in different levels of
impact.

iii

NUREG-1437, Revision 2

Paperwork Reduction Act Statement
This NUREG provides voluntary guidance for implementing the mandatory information
collections in 10 CFR Part 51 that are subject to the Paperwork Reduction Act of 1995
(44 U.S.C. 3501 et seq.). These information collections were approved by the Office of
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these information collections to the FOIA, Library, and Information Collections Branch
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Infocollects.Resource@nrc.gov, and to the OMB reviewer at: OMB Office of Information and
Regulatory Affairs (3150-0021). Attn: Desk Officer for the Nuclear Regulatory Commission,
725 17th Street NW, Washington, DC 20503; email: oira_submission@omb.eop.gov.
Public Protection Notification
The NRC may not conduct or sponsor, and a person is not required to respond to, a request for
information or an information collection requirement unless the requesting document displays a
currently valid Office of Management and Budget control number.

NUREG-1437, Revision 2

iv

TABLE OF CONTENTS
ABSTRACT ................................................................................................................... iii
LIST OF FIGURES....................................................................................................... xiii
LIST OF TABLES ......................................................................................................... xv
ACRONYMS, ABBREVIATIONS, AND CHEMICAL NOMENCLATURE .................... xxi
SHORTENED NUCLEAR POWER PLANT NAMES USED IN THIS REPORT ....... xxvii
CONVERSION TABLE .............................................................................................. xxix
EXECUTIVE SUMMARY ........................................................................................... xxxi
ES.1
ES.2
ES.3
ES.4
ES.5

Purpose and Need for the Proposed Action ...................................................... xxxiii
Development of the Revised Generic Environmental Impact Statement ........... xxxiv
Impact Definitions and Categories .....................................................................xxxv
Affected Environment ....................................................................................... xxxvi
Impacts from Continued Operations and Refurbishment Activities
Associated with License Renewal (Initial or Subsequent) ................................. xxxvi
ES.6 Comparison of Alternatives .............................................................................. xxxvii

1

INTRODUCTION ................................................................................................. 1-1
1.1
1.2
1.3
1.4
1.5

1.6
1.7

1.8

Purpose of the LR GEIS ......................................................................................1-2
Description of the Proposed Action ......................................................................1-3
Purpose and Need for the Proposed Action .........................................................1-3
Alternatives to the Proposed Action .....................................................................1-4
Analytical Approach Used in the LR GEIS ...........................................................1-4
1.5.1
Objectives .............................................................................................1-4
1.5.2
Methodology .........................................................................................1-4
1.5.2.1
Defining Environmental Issues ...........................................1-5
1.5.2.2
Collecting Information .........................................................1-5
1.5.2.3
Impact Definitions and Categories ......................................1-5
Scope of the LR GEIS Revision ...........................................................................1-7
Decisions to Be Supported by the LR GEIS .........................................................1-9
1.7.1
Changes to Nuclear Power Plant Cooling Systems .............................1-10
1.7.2
Disposition of Spent Nuclear Fuel .......................................................1-10
1.7.3
Emergency Preparedness ...................................................................1-12
1.7.4
Safeguards and Security .....................................................................1-14
1.7.5
Need for Power ...................................................................................1-14
1.7.6
Seismicity, Flooding, and Other Natural Hazards ................................1-15
Implementation of the Rule (10 CFR Part 51) ....................................................1-15

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Table of Contents

1.9
1.10
1.11
1.12

2

ALTERNATIVES INCLUDING THE PROPOSED ACTION ................................ 2-1
2.1

2.2
2.3
2.4

3

1.8.1
General Requirements ........................................................................1-15
1.8.2
Applicant’s Environmental Report .......................................................1-15
1.8.3
Supplemental Environmental Impact Statement ..................................1-16
1.8.4
Public Scoping and Public Comments .................................................1-16
1.8.5
Draft Supplemental Environmental Impact Statement .........................1-16
1.8.6
Final Supplemental Environmental Impact Statement .........................1-17
1.8.7
Consultations ......................................................................................1-17
Public Scoping Comments on the LR GEIS Update ...........................................1-18
Public Comments on the Draft LR GEIS ............................................................1-19
Lessons Learned ...............................................................................................1-21
Organization of the LR GEIS .............................................................................1-22

Proposed Action ..................................................................................................2-2
2.1.1
Nuclear Plant Operations during the License Renewal Term.................2-2
2.1.2
Refurbishment and Other Activities Associated with License
Renewal ................................................................................................2-3
2.1.3
Termination of Nuclear Plant Operations and Decommissioning
after License Renewal ...........................................................................2-4
2.1.4
Impacts of the Proposed Action.............................................................2-4
No Action Alternative .........................................................................................2-16
Alternative Energy Sources ...............................................................................2-16
Comparison of Alternatives ................................................................................2-17

AFFECTED ENVIRONMENT .............................................................................. 3-1
3.1

3.2

3.3

Description of Nuclear Power Plant Facilities and Operations ..............................3-1
3.1.1
External Appearance and Settings ........................................................3-1
3.1.2
Nuclear Reactor Systems ......................................................................3-2
3.1.3
Cooling Water Systems .........................................................................3-9
3.1.4
Radioactive Waste Management Systems ..........................................3-14
3.1.4.1
Liquid Radioactive Waste .................................................3-14
3.1.4.2
Gaseous Radioactive Waste ............................................3-15
3.1.4.3
Solid Radioactive Waste ...................................................3-16
3.1.5
Nonradioactive Waste Management Systems .....................................3-17
3.1.6
Utility and Transportation Infrastructure ...............................................3-18
3.1.7
Power Transmission Systems .............................................................3-18
3.1.8
Nuclear Power Plant Operations and Maintenance .............................3-18
Land Use and Visual Resources ........................................................................3-19
3.2.1
Land Use.............................................................................................3-19
3.2.2
Visual Resources ................................................................................3-21
Meteorology, Air Quality, and Noise ...................................................................3-21
3.3.1
Meteorology and Climatology ..............................................................3-21

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3.4
3.5

3.6

3.7

3.8

3.9

3.3.2
Air Quality ...........................................................................................3-23
3.3.3
Noise...................................................................................................3-28
Geologic Environment .......................................................................................3-29
Water Resources ...............................................................................................3-33
3.5.1
Surface Water Resources ...................................................................3-35
3.5.1.1
Surface Water Use ...........................................................3-35
3.5.1.2
Surface Water Quality ......................................................3-38
3.5.1.3
Hydrologic Changes and Flooding ....................................3-41
3.5.2
Groundwater Resources .....................................................................3-42
3.5.2.1
Groundwater Use .............................................................3-42
3.5.2.2
Groundwater Quality.........................................................3-43
Ecological Resources ........................................................................................3-46
3.6.1
Terrestrial Resources ..........................................................................3-46
3.6.1.1
Upland Vegetation and Habitats .......................................3-46
3.6.1.2
Floodplain and Wetland Vegetation and Habitats .............3-47
3.6.1.3
Wildlife..............................................................................3-49
3.6.2
Aquatic Resources ..............................................................................3-50
3.6.2.1
Aquatic Habitats ...............................................................3-50
3.6.2.2
Aquatic Organisms ...........................................................3-52
3.6.2.3
Effects of Existing Nuclear Plant Operations on
Aquatic Resources ...........................................................3-53
3.6.3
Federally Protected Ecological Resources ..........................................3-55
3.6.3.1
Endangered Species Act ..................................................3-56
3.6.3.2
Magnuson-Stevens Fishery Conservation and
Management Act ..............................................................3-72
3.6.3.3
National Marine Sanctuaries Act.......................................3-77
Historic and Cultural Resources.........................................................................3-79
3.7.1
Scope of Review .................................................................................3-79
3.7.2
NEPA and NHPA ................................................................................3-80
3.7.3
Historic and Cultural Resources at Nuclear Power Plant Sites ............3-81
Socioeconomics ................................................................................................3-82
3.8.1
Power Plant Employment and Expenditures........................................3-82
3.8.2
Regional Economic Characteristics .....................................................3-83
3.8.2.1
Rural Economies ..............................................................3-84
3.8.2.2
Urban Economies .............................................................3-84
3.8.3
Demographic Characteristics ..............................................................3-84
3.8.4
Housing and Community Services ......................................................3-85
3.8.5
Tax Revenue.......................................................................................3-86
3.8.6
Local Transportation ...........................................................................3-87
Human Health....................................................................................................3-87
3.9.1
Radiological Exposure and Risk ..........................................................3-87

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3.10
3.11

3.12

4

3.9.1.1
Regulatory Requirements .................................................3-87
3.9.1.2
Occupational Radiological Exposures ..............................3-90
3.9.1.3
Public Radiological Exposures .......................................3-111
3.9.1.4
Radiation Health Effects Studies ....................................3-119
3.9.2
Nonradiological Hazards ...................................................................3-120
3.9.2.1
Chemical Hazards ..........................................................3-121
3.9.2.2
Microbiological Hazards .................................................3-122
3.9.2.3
Electromagnetic Fields (EMFs) .......................................3-125
3.9.2.4
Physical Hazards ............................................................3-126
Environmental Justice......................................................................................3-129
Waste Management and Pollution Prevention .................................................3-131
3.11.1 Radioactive Waste ............................................................................3-132
3.11.1.1
Low-Level Radioactive Waste ........................................3-132
3.11.1.2
Spent Nuclear Fuel .........................................................3-135
3.11.2 Hazardous Waste..............................................................................3-138
3.11.3 Mixed Waste .....................................................................................3-138
3.11.4 Nonhazardous Waste ........................................................................3-139
3.11.5 Pollution Prevention and Waste Minimization ....................................3-139
Greenhouse Gas Emissions and Climate Change ...........................................3-139
3.12.1 Greenhouse Gas Emissions ..............................................................3-139
3.12.2 Observed Changes in Climate...........................................................3-144

ENVIRONMENTAL CONSEQUENCES AND MITIGATING ACTIONS .............. 4-1
4.1

4.2

4.3

Environmental Consequences and Mitigating Actions ..........................................4-2
4.1.1
Introduction ...........................................................................................4-2
4.1.2
Environmental Consequences of the Proposed Action ..........................4-2
4.1.3
Environmental Consequences of Continued Operations and
Refurbishment Activities During the License Renewal Term (Initial
or Subsequent) .....................................................................................4-3
4.1.4
Environmental Consequences of the No Action Alternative ...................4-4
4.1.5
Environmental Consequences of Alternative Energy Sources ...............4-4
4.1.6
Environmental Consequences of Terminating Nuclear Power Plant
Operations and Decommissioning .........................................................4-5
Land Use and Visual Resources ..........................................................................4-5
4.2.1
Environmental Consequences of the Proposed Action – Continued
Operations and Refurbishment Activities ...............................................4-5
4.2.1.1
Land Use ............................................................................4-5
4.2.1.2
Visual Resources ...............................................................4-7
Air Quality and Noise ...........................................................................................4-8
4.3.1
Environmental Consequences of the Proposed Action – Continued
Operations and Refurbishment Activities ...............................................4-8
4.3.1.1
Air Quality...........................................................................4-8

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4.4

4.5

4.6

4.7

4.8

4.9

4.10

4.11

4.3.1.2
Noise ................................................................................4-13
Geologic Environment .......................................................................................4-14
4.4.1
Environmental Consequences of the Proposed Action – Continued
Operations and Refurbishment Activities .............................................4-14
4.4.1.1
Geology and Soils ............................................................4-14
Water Resources ...............................................................................................4-16
4.5.1
Environmental Consequences of the Proposed Action – Continued
Operations and Refurbishment Activities .............................................4-16
4.5.1.1
Surface Water Resources.................................................4-16
4.5.1.2
Groundwater Resources ...................................................4-27
Ecological Resources ........................................................................................4-44
4.6.1
Environmental Consequences of the Proposed Action – Continued
Operations and Refurbishment Activities .............................................4-44
4.6.1.1
Terrestrial Resources .......................................................4-45
4.6.1.2
Aquatic Resources ...........................................................4-64
4.6.1.3
Federally Protected Ecological Resources .....................4-102
Historic and Cultural Resources.......................................................................4-113
4.7.1
Environmental Consequences of the Proposed Action – Continued
Operations and Refurbishment Activities ...........................................4-113
Socioeconomics ..............................................................................................4-114
4.8.1
Environmental Consequences of the Proposed Action – Continued
Operations and Refurbishment Activities ...........................................4-114
4.8.1.1
Employment and Income, Recreation, and Tourism .......4-115
4.8.1.2
Tax Revenue ..................................................................4-116
4.8.1.3
Community Services and Education ...............................4-117
4.8.1.4
Population and Housing .................................................4-117
4.8.1.5
Transportation ................................................................4-118
Human Health..................................................................................................4-118
4.9.1
Environmental Consequences of the Proposed Action – Continued
Operations and Refurbishment Activities ...........................................4-118
4.9.1.1
Environmental Consequences of Normal Operating
Conditions ......................................................................4-119
4.9.1.2
Environmental Consequences of Postulated
Accidents........................................................................4-129
Environmental Justice......................................................................................4-132
4.10.1 Environmental Consequences of the Proposed Action – Continued
Operations and Refurbishment Activities ...........................................4-132
4.10.1.1
Impacts on Minority Populations, Low-Income
Populations, and Indian Tribes .......................................4-133
Waste Management and Pollution Prevention .................................................4-134
4.11.1 Environmental Consequences of the Proposed Action – Continued
Operations and Refurbishment Activities ...........................................4-134
4.11.1.1
Low-Level Waste Storage and Disposal .........................4-135

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Table of Contents
4.11.1.2
4.11.1.3

4.12

4.13

4.14

4.15

5

Onsite Storage of Spent Nuclear Fuel ............................4-136
Offsite Radiological Impacts of Spent Nuclear Fuel
and High-Level Waste Disposal ......................................4-137
4.11.1.4
Mixed Waste Storage and Disposal ................................4-141
4.11.1.5
Nonradioactive Waste Storage and Disposal ..................4-142
Greenhouse Gas Emissions and Climate Change ...........................................4-142
4.12.1 Greenhouse Gas Impacts on Climate Change ..................................4-143
4.12.2 Climate Change Impacts on Environmental Resources .....................4-144
Cumulative Effects of the Proposed Action ......................................................4-146
4.13.1 Air Quality .........................................................................................4-148
4.13.2 Surface Water Resources .................................................................4-148
4.13.3 Groundwater Resources ...................................................................4-148
4.13.4 Ecological Resources ........................................................................4-148
4.13.5 Historic and Cultural Resources ........................................................4-149
4.13.6 Socioeconomics ................................................................................4-149
4.13.7 Human Health ...................................................................................4-149
4.13.8 Environmental Justice .......................................................................4-150
4.13.9 Waste Management and Pollution Prevention ...................................4-150
Impacts Common to All Alternatives ................................................................4-150
4.14.1 Environmental Consequences of the Uranium Fuel Cycle .................4-150
4.14.1.1
Background on Uranium Fuel Cycle Facilities.................4-151
4.14.1.2
Environmental Impacts ...................................................4-152
4.14.1.3
Consideration of Environmental Justice ..........................4-158
4.14.1.4
Transportation Impacts ...................................................4-158
4.14.1.5
Environmental Impact Issues of the Uranium Fuel
Cycle ..............................................................................4-161
4.14.2 Environmental Consequences of Terminating Operations and
Decommissioning ..............................................................................4-164
4.14.2.1
Termination of Nuclear Power Plant Operations and
Decommissioning ...........................................................4-164
Resource Commitments Associated with the Proposed Action ........................4-171
4.15.1 Unavoidable Adverse Environmental Impacts ...................................4-171
4.15.2 Relationship between Short-Term Use of the Environment and
Long-Term Productivity .....................................................................4-173
4.15.3 Irreversible and Irretrievable Commitment of Resources ...................4-174

REFERENCES .................................................................................................... 5-1

APPENDIX A – COMMENTS RECEIVED ON THE ENVIRONMENTAL REVIEW .... A-1

NUREG-1437, Revision 2

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APPENDIX B – COMPARISON OF ENVIRONMENTAL ISSUES AND
FINDINGS IN THIS LR GEIS REVISION TO THE ISSUES AND
FINDINGS IN TABLE B-1 OF 10 CFR PART 51 (1996, 2013,
AND 2024 REVISIONS) ................................................................... B-1
APPENDIX C – GENERAL CHARACTERISTICS AND ENVIRONMENTAL
SETTINGS OF OPERATING DOMESTIC NUCLEAR POWER
PLANTS ........................................................................................... C-1
APPENDIX D – ALTERNATIVES TO THE PROPOSED ACTION
CONSIDERED IN THE LR GEIS...................................................... D-1
APPENDIX E – ENVIRONMENTAL IMPACT OF POSTULATED ACCIDENTS .......E-1
APPENDIX F – LAWS, REGULATIONS, AND OTHER REQUIREMENTS ............... F-1
APPENDIX G – TECHNICAL SUPPORT FOR LR GEIS ANALYSES ...................... G-1
APPENDIX H – LIST OF PREPARERS .................................................................... H-1
APPENDIX I – DISTRIBUTION LIST ......................................................................... I-1
APPENDIX J – GLOSSARY ...................................................................................... J-1

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NUREG-1437, Revision 2

LIST OF FIGURES
Figure 3.1-1
Figure 3.1-2
Figure 3.1-3
Figure 3.1-4
Figure 3.3-1

Figure 3.4-1
Figure 3.4-2

Figure 3.6-1
Figure 3.9-1
Figure 3.9-2
Figure 3.9-3
Figure 3.11-1
Figure 3.11-2
Figure 3.12-1
Figure D.3-1
Figure D.3-2
Figure D.3-3
Figure D.3-4
Figure D.3-5
Figure D.3-6
Figure D.3-7
Figure D.3-8
Figure D.3-9
Figure D.3-10
Figure D.3-11
Figure D.3-12
Figure D.3-13
Figure E.3-1
Figure E.3-2
Figure E.3-3
Figure E.3-4

Operating Commercial Nuclear Power Plants in the United States ..............3-3
Pressurized Water Reactor .........................................................................3-8
Boiling Water Reactor .................................................................................3-9
Schematic Diagrams of Nuclear Power Plant Cooling Systems.................3-13
Locations of Operating Nuclear Plants Relative to U.S. Environmental
Protection Agency Nonattainment Areas Revoked 1-hour and 8-hour
Ozone are Excluded. .................................................................................3-25
Occurrence of Prime Farmland and Other Farmland of Importance,
with Nuclear Power Plant Locations Shown ..............................................3-31
2018 National Seismic Hazard Model Peak Horizontal Acceleration
with a 2 Percent Probability of Exceedance in 50 Years with Nuclear
Power Plant Locations Shown ...................................................................3-32
National Marine Sanctuaries and Marine National Monuments .................3-77
Average, Median, and Extreme Values of the Collective Dose per
Boiling Water Reactor from 1994 through 2020 .........................................3-96
Average, Median, and Extreme Values of the Collective Dose per
Pressurized Water Reactor from 1994 through 2020 .................................3-97
Dose Distribution for All Commercial U.S. Reactors by Dose Range,
2016 through 2020 ..................................................................................3-110
Typical Dry Cask Storage Systems .........................................................3-136
Locations of Independent Spent Fuel Storage Installations Licensed
by the NRC .............................................................................................3-137
Locations of Operating Nuclear Power Plants Relative to National
Climate Assessment Geographic Regions ..............................................3-145
Schematic of a Natural Gas-Fired Plant ..................................................... D-4
Schematic of a Coal-Fired Power Plant ...................................................... D-5
Schematic of a Large Light Water Reactor. ................................................ D-7
Schematic of a Light Water Small Modular Nuclear Reactor ...................... D-8
Schematic of Solar Photovoltaic Power Plant ........................................... D-10
Schematic of Concentrated Solar Power Plant ......................................... D-11
Components of a Modern Horizontal-Axis Wind Turbine .......................... D-12
Major Offshore Wind Power Plant and Transmission Elements ................ D-13
Cross Section of a Large Hydroelectric Plant ........................................... D-14
Schematic of a Biomass/Waste-to-Energy Plant ...................................... D-15
Schematic of a Hydrothermal Binary Power Plant .................................... D-16
Primary Types of Wave Energy Devices .................................................. D-17
Components of a Hydrogen Fuel Cell....................................................... D-18
Comparison of Recent and Past Estimates for Total Core Damage
Frequency ................................................................................................ E-25
Iodine Release to the Environment for SOARCA Unmitigated
Scenarios and the 1982 Siting Study SST1 Case..................................... E-41
Cesium Release to the Environment for SOARCA Unmitigated
Scenarios and the 1982 Siting Study SST1 Case..................................... E-41
Percentages of Cesium and Iodine Released to the Environment for
SOARCA Unmitigated Scenarios, the 1982 Siting Study SST1 Case,
and Historical Accidents ........................................................................... E-42

xiii

NUREG-1437, Revision 2

List of Figures
Figure E.3-5

Figure E.3-6

Figure E.3-7

Figure E.3-8

Figure G.3-1
Figure G.3-2
Figure G.3-3
Figure G.6-1

Comparison of Population-Weighted Average Individual Latent
Cancer Fatality Risk Results from NUREG-2161 to the NRC Safety
Goal ......................................................................................................... E-63
Uncertainty in Average Individual Latent Cancer Fatality Risk in the
2015 Containment Protection and Release Reduction Regulatory
Analysis ................................................................................................... E-71
Complementary Cumulative Distribution Functions of Conditional
Individual Latent Cancer Fatality Risk within Five Annular Areas
Centered on the Sequoyah Plant ............................................................. E-80
Complementary Cumulative Distribution Functions of Conditional
Individual Latent Cancer Fatality Risk within Five Annular Areas
Centered on the Surry Plant ..................................................................... E-80
Average Annual Maximum Temperatures across the Continental
United States ............................................................................................. G-7
Average Annual Minimum Temperatures across the Continental
United States ............................................................................................. G-8
Average Annual Precipitation across the Continental United States ........... G-9
Level I Ecoregions of the United States .................................................... G-15

NUREG-1437, Revision 2

xiv

LIST OF TABLES
Table 2.1-1
Table 2.4-1
Table 2.4-2
Table 2.4-3
Table 2.4-4

Table 2.4-5
Table 3.1-1
Table 3.1-2
Table 3.1-3
Table 3.1-4
Table 3.2-1
Table 3.3-1
Table 3.3-2
Table 3.5-1
Table 3.6-1
Table 3.6-2
Table 3.6-3
Table 3.6-4
Table 3.6-5
Table 3.6-6
Table 3.6-7
Table 3.8-1
Table 3.8-2
Table 3.9-1
Table 3.9-2
Table 3.9-3

Summary of Findings on Environmental Issues under the
Proposed Action ..........................................................................................2-5
Construction under the Proposed Action and Alternatives –
Assessment Basis and Nature of Impacts .................................................2-19
Operations under the Proposed Action and Alternatives – Assessment
Basis and Nature of Impacts .....................................................................2-20
Postulated Accidents under the Proposed Action and Alternatives –
Assessment Basis and Impact Magnitude .................................................2-21
Termination of Nuclear Power Plant Operations and Decommissioning
under the Proposed Action and Alternatives – Assessment Basis and
Nature of Impacts ......................................................................................2-22
Fuel Cycle under the Proposed Action and Alternatives – Assessment
Basis and Nature of Impacts .....................................................................2-23
Characteristics of Operating U.S. Commercial Nuclear Power Plants .........3-4
Cooling Water System Source – Coastal or Estuarine Environment ..........3-10
Cooling Water System Source – Great Lakes Environment ......................3-10
Cooling Water System Source – Freshwater Riverine or Impoundment
Environment ..............................................................................................3-10
Percent of Land Cover Types within a 5-Mile Radius of Nuclear Power
Plants ........................................................................................................3-21
Fujita Tornado Intensity Scale ...................................................................3-23
National Ambient Air Quality Standards for Six Criteria Pollutants .............3-24
Comparison of Cooling Water System Attributes for Operating
Commercial Nuclear Power Plants ............................................................3-37
Factors That Influence the Impacts of Nuclear Power Plant Operation
on Aquatic Organisms ...............................................................................3-54
Critical Habitats Evaluated in License Renewal Reviews,
2013–Present............................................................................................3-57
National Marine Fisheries Service-Issued Biological Opinions for
Nuclear Power Plant Operation .................................................................3-59
U.S. Fish and Wildlife Service-Issued Biological Opinions for Nuclear
Power Plant Operation ..............................................................................3-60
Endangered Species Act Listed Species Evaluated in License
Renewal Reviews, 2013–Present ..............................................................3-64
Essential Fish Habitat Evaluated in License Renewal Reviews,
2013–Present............................................................................................3-75
National Marine Sanctuaries Near Operating Nuclear Power Plants .........3-78
Local Employment and Tax Revenues at 15 Nuclear Plants from 2014
through 2020 .............................................................................................3-83
Population Classification of Regions around Selected Nuclear Power
Plants ........................................................................................................3-85
Occupational Dose Limits for Adults Established by 10 CFR Part 20 ........3-88
Design Objectives and Annual Standards on Doses to the General
Public from Nuclear Power Plants from Appendix I to 10 CFR 50 .............3-89
Design Objectives and Annual Standards on Doses to the General
Public from Nuclear Power Plants from 40 CFR 190, Subpart B ...............3-90

xv

NUREG-1437, Revision 2

List of Tables
Table 3.9-4
Table 3.9-5
Table 3.9-6
Table 3.9-7
Table 3.9-8
Table 3.9-9

Table 3.9-10
Table 3.9-11
Table 3.9-12
Table 3.9-13

Table 3.9-14

Table 3.9-15

Table 3.9-16

Table 3.9-17

Table 3.9-18

Table 3.9-19

Table 3.9-20
Table 3.9-21
Table 3.9-22
Table 3.9-23
Table 3.9-24

Occupational Whole-Body Dose Data at U.S. Commercial Nuclear
Power Plants .............................................................................................3-91
Annual Average Measurable Occupational Dose per Individual for
U.S. Commercial Nuclear Power Plants in rem .........................................3-92
Annual Average Collective Occupational Dose for U.S. Commercial
Nuclear Power Plants in Person-rem.........................................................3-93
Collective and Individual Worker Doses at Boiling Water Reactors
from 2018 through 2020 ............................................................................3-93
Collective and Individual Worker Doses at Pressurized Water
Reactors from 2018 through 2020 .............................................................3-94
Annual Collective Dose and Annual Occupational Dose for
Pressurized Water Reactor Nuclear Power Plants from 2006
through 2020 .............................................................................................3-98
Annual Collective Dose and Annual Occupational Dose for Boiling
Water Reactor Nuclear Power Plants from 2006 through 2020 .................3-99
Annual Collective Dose for Pressurized Water Reactor Nuclear Power
Plants from 2006 through 2020 ...............................................................3-101
Annual Collective Dose for Boiling Water Reactor Nuclear Power
Plants from 2006 through 2020 ...............................................................3-103
Annual Average Measurable Occupational Doses at Pressurized
Water Reactor Commercial Nuclear Power Plant Sites from 2006
through 2020 ...........................................................................................3-104
Annual Average Measurable Occupational Doses at Boiling Water
Reactor Commercial Nuclear Power Plant Sites from 2006
through 2020 ...........................................................................................3-106
Average, Maximum, and Minimum Annual Collective Occupational
Dose per Plant for Pressurized Water Reactor Nuclear Power Plants
in Person-rem .........................................................................................3-108
Average, Maximum, and Minimum Annual Collective Occupational
Dose per Plant for Boiling Water Reactor Nuclear Power Plants in
Person-rem .............................................................................................3-108
Average, Maximum, and Minimum Annual Individual Occupational
Whole-Body Dose for Pressurized Water Reactor Nuclear
Power Plants in rem ................................................................................3-108
Average, Maximum, and Minimum Annual Individual Occupational
Whole-Body Dose for Boiling Water Reactor Nuclear Power Plants in
rem..........................................................................................................3-109
Number of Workers at Boiling Water Reactors and Pressurized Water
Reactors Who Received Whole-Body Doses within Specified Ranges
during 2020 .............................................................................................3-109
Collective and Average Committed Effective Dose Equivalent for
Commercial U.S. Nuclear Power Plant Sites in 2020 ..............................3-110
Doses from Gaseous Effluent Releases by Select Pressurized Water
Reactors from 2019 through 2021 ...........................................................3-114
Doses from Gaseous Effluent Releases by Select Boiling Water
Reactors from 2019 through 2021 ...........................................................3-115
Dose from Liquid Effluent Releases by Select Pressurized Water
Reactor Nuclear Power Plants for 2019 through 2021 .............................3-116
Dose from Liquid Effluent Releases from Select Boiling Water Reactor
Nuclear Power Plants for 2019 through 2021 ..........................................3-117

NUREG-1437, Revision 2

xvi

List of Tables
Table 3.9-25
Table 3.9-26
Table 3.9-27
Table 3.9-28
Table 3.9-29
Table 3.11-1
Table 3.11-2
Table 3.12-1
Table 3.12-2
Table 4.6-1

Table 4.6-2
Table 4.6-3
Table 4.6-4
Table 4.6-5
Table 4.6-6
Table 4.6-7
Table 4.6-8
Table 4.6-9
Table 4.6-10
Table 4.6-11
Table 4.9-1

Table 4.14-1
Table 4.14-2

Table 4.14-3
Table A.2-1
Table A.2-2
Table B.1-1

Average Annual Effective Dose Equivalent of Ionizing Radiation to
a Member of the U.S. Population for 2016...............................................3-118
Nominal Probability Coefficients Used in ICRP .......................................3-119
Number and Rate of Fatal Occupational Injuries by Industry Sector
in 2021 ....................................................................................................3-127
Incidence Rate of Nonfatal Occupational Injuries and Illnesses in
Different Utilities in 2021 .........................................................................3-127
Number and Rate of Fatal Occupational Injuries for Selected
Occupations in 2021 ...............................................................................3-128
Solid Low-Level Radioactive Waste Shipped Offsite per Reactor from
Select Pressurized Water Reactor Power Plant Sites in 2021 .................3-134
Solid Low-Level Radioactive Waste Shipped Offsite per Reactor from
Select Boiling Water Reactor Power Plant Sites in 2021 .........................3-134
Greenhouse Gas Emissions by State, 2021 ............................................3-140
Estimated Greenhouse Gas Emissions from Operations at Nuclear
Power Plants ...........................................................................................3-143
Estimated Radiation Dose Rates to Terrestrial Ecological Receptors
from Radionuclides in Water, Sediment, and Soils at U.S. Nuclear
Power Plants .............................................................................................4-51
Estimated Annual Bird Collision Mortality in the United States ..................4-57
Commonly Impinged and Entrained Taxa at Nuclear Power Plants by
Ecosystem Type........................................................................................4-68
Results of NRC Impingement and Entrainment Analyses at Nuclear
Power Plants, 2013–Present .....................................................................4-72
Results of NRC Thermal Analyses at Nuclear Power Plants,
2013–Present............................................................................................4-77
Possible Endangered Species Act Effect Determinations ........................4-104
Appropriate Type of Consultation by Endangered Species Act Effect
Determination ..........................................................................................4-105
Possible Essential Fish Habitat Effect Determinations ............................4-109
Appropriate Type of Consultation by Type of Proposed Action and
Essential Fish Habitat Effect Determination.............................................4-109
Types of Sanctuary Resources ...............................................................4-111
Possible National Marine Sanctuaries Act Effect Determinations ............4-112
Additional Collective Occupational Dose for Different Actions under
Typical and Conservative Scenarios during the License Renewal
Term .......................................................................................................4-120
Table S-3 Taken from 10 CFR 51.51 on Uranium Fuel Cycle
Environmental Data.................................................................................4-155
Table S-4 Taken from 10 CFR 51.52 on the Environmental Impact of
Transporting Fuel and Waste to and from One Light Water-Cooled
Nuclear Power Reactor ...........................................................................4-159
Population Doses from Uranium Fuel Cycle Facilities Normalized to
One Reference Reactor Year ..................................................................4-163
Individuals Providing Comments on the Proposed Rule Package .............. A-4
Commenter Categories .............................................................................. A-7
Comparison of Land Use-Related Environmental Issues and Findings
in This LR GEIS Revision to Prior Versions of Table B-1 of
10 CFR Part 51 .......................................................................................... B-2

xvii

NUREG-1437, Revision 2

List of Tables
Table B.1-2

Table B.1-3

Table B.1-4

Table B.1-5

Table B.1-6

Table B.1-7

Table B.1-8

Table B.1-9

Table B.1-10

Table B.1-11

Table B.1-12

Table B.1-13

Table B.1-14

Table B.1-15

Table B.1-16

Table B.1-17

Table B.1-18

Comparison of Visual Resource-Related Environmental Issues and
Findings in This LR GEIS Revision to Prior Versions of Table B-1 of
10 CFR Part 51 .......................................................................................... B-4
Comparison of Air Quality-Related Environmental Issues and Findings
in This LR GEIS Revision to Prior Versions of Table B-1 of
10 CFR Part 51 .......................................................................................... B-5
Comparison of Noise-Related Environmental Issues and Findings in
This LR GEIS Revision to Prior Versions of Table B-1 of
10 CFR Part 51 .......................................................................................... B-7
Comparison of Geologic Environment-Related Environmental Issues
and Findings in This LR GEIS Revision to Prior Versions of Table B-1
of 10 CFR Part 51 ...................................................................................... B-8
Comparison of Surface Water Resources-Related Environmental
Issues and Findings in This LR GEIS Revision to Prior Versions of
Table B-1 of 10 CFR Part 51 ...................................................................... B-9
Comparison of Groundwater Resources-Related Environmental
Issues and Findings in This LR GEIS Revision to Prior Versions of
Table B-1 of 10 CFR Part 51 .................................................................... B-13
Comparison of Terrestrial Resources-Related Environmental Issues
and Findings in This LR GEIS Revision to Prior Versions of Table B-1
of 10 CFR Part 51 .................................................................................... B-17
Comparison of Aquatic Resources-Related Environmental Issues and
Findings in This LR GEIS Revision to Prior Versions of Table B-1 of
10 CFR Part 51 ........................................................................................ B-23
Comparison of Federally Protected Ecological Resources-Related
Environmental Issues and Findings in This LR GEIS Revision to Prior
Versions of Table B-1 of 10 CFR Part 51 ................................................. B-34
Comparison of Historic and Cultural Resources-Related
Environmental Issues and Findings in This LR GEIS Revision to Prior
Versions of Table B-1 of 10 CFR Part 51 ................................................. B-37
Comparison of Socioeconomics-Related Environmental Issues and
Findings in This LR GEIS Revision to Prior Versions of Table B-1 of
10 CFR Part 51 ........................................................................................ B-38
Comparison of Human Health-Related Environmental Issues and
Findings in This LR GEIS Revision to Prior Versions of Table B-1 of
10 CFR Part 51 ........................................................................................ B-42
Comparison of Postulated Accidents-Related Environmental Issues
and Findings in This LR GEIS Revision to Prior Versions of Table B-1
of 10 CFR Part 51 .................................................................................... B-47
Comparison of Environmental Justice-Related Environmental Issues
and Findings in This LR GEIS Revision to Prior Versions of Table B-1
of 10 CFR Part 51 .................................................................................... B-48
Comparison of Waste Management-Related Environmental Issues
and Findings in This LR GEIS Revision to Prior Versions of Table B-1
of 10 CFR Part 51 .................................................................................... B-49
Comparison of Greenhouse Gas Emissions and Climate ChangeRelated Environmental Issues and Findings in This LR GEIS Revision
to Prior Versions of Table B-1 of 10 CFR Part 51 ..................................... B-55
Comparison of Cumulative Effects-Related Environmental Issues and
Findings in This LR GEIS Revision to Prior Versions of Table B-1 of
10 CFR Part 51 ........................................................................................ B-57

NUREG-1437, Revision 2

xviii

List of Tables
Table B.1-19

Table B.1-20

Table D.3-1
Table D.4-1
Table D.4-2
Table D.4-3
Table E.3-1
Table E.3-2
Table E.3-3
Table E.3-4
Table E.3-5
Table E.3-6
Table E.3-7
Table E.3-8
Table E.3-9
Table E.3-10
Table E.3-11
Table E.3-12
Table E.3-13
Table E.3-14
Table E.3-15
Table E.3-16
Table E.3-17
Table E.3-18
Table E.3-19
Table E.3-20
Table E.3-21

Table E.3-22

Comparison of Uranium Fuel Cycle-Related Environmental Issues
and Findings in This LR GEIS Revision to Prior Versions of Table B-1
of 10 CFR Part 51 .................................................................................... B-58
Comparison of Termination of Nuclear Power Plant Operations and
Decommissioning-Related Environmental Issues and Findings in This
LR GEIS Revision to Prior Versions of Table B-1 of 10 CFR Part 51........ B-61
Net Generation at Utility-Scale Facilities .................................................... D-3
Emission Factors of Representative Fossil Fuel Plants ............................ D-24
Water Withdrawal and Consumptive Use Factors for Select Electric
Power Technologies ................................................................................. D-28
Carbon Dioxide Emission Factors for Representative Fossil Fuel
Plants ....................................................................................................... D-40
Comparison of 1996 LR GEIS-Predicted Risks to License Renewal
Estimated Risks ......................................................................................... E-9
Pressurized Water Reactor Internal Event Core Damage Frequency
Comparison.............................................................................................. E-18
Boiling Water Reactor Internal Event Core Damage Frequency
Comparison.............................................................................................. E-19
Pressurized Water Reactor Internal Event Population Dose Risk
Comparison.............................................................................................. E-20
Boiling Water Reactor Internal Event Population Dose Risk
Comparison.............................................................................................. E-21
Pressurized Water Reactor All Hazards Core Damage Frequency
Comparison.............................................................................................. E-24
Boiling Water Reactor All Hazards Core Damage Frequency
Comparison.............................................................................................. E-25
Pressurized Water Reactor All Hazards Population Dose Risk
Comparison.............................................................................................. E-27
Boiling Water Reactors All Hazards Population Dose Risk
Comparison.............................................................................................. E-28
Fire Core Damage Frequency Comparison .............................................. E-29
Seismic Core Damage Frequency Comparison ........................................ E-33
Pressurized Water Reactor and Boiling Water Reactor All Hazards
Core Damage Frequency Comparison ..................................................... E-36
Brief Source Term Description for Unmitigated Peach Bottom
Accident Scenarios and the SST1 from the 1982 Siting Study ................. E-40
Brief Source Term Description for Unmitigated Surry Accident
Scenarios and the SST1 from the 1982 Siting Study ............................... E-40
SOARCA Results: Long-Term Cancer Fatality Risk ................................. E-43
Changes in Large Early Release Frequencies for Extended Power
Uprates .................................................................................................... E-47
Loss-of-Coolant Accident Consequences as a Function of Fuel
Burnup ..................................................................................................... E-51
Airborne Impacts of Low Power and Shutdown Accidents ........................ E-55
Impacts of Accidents at Spent Fuel Pools from NUREG-1738.................. E-60
Uncertainty Analysis Inputs ...................................................................... E-71
Ratio of Consequence Results for Population Density Sensitivity
Cases in the 2015 Containment Protection and Release Reduction
Regulatory Analysis ................................................................................. E-73
Uncertain MELCOR Parameters Chosen for the SOARCA
Unmitigated Station Blackout Uncertainty Analyses ................................. E-76

xix

NUREG-1437, Revision 2

List of Tables
Table E.3-23
Table E.3-24

Table E.3-25

Table E.5-1
Table F.5-1
Table F.5-2
Table F.5-3
Table F.5-4
Table F.5-5
Table F.5-6
Table F.6-1
Table F.6-2
Table F.6-3
Table F.6-4
Table F.6-5
Table F.6-6
Table G.3-1
Table G.6-1

Table G.6-2
Table G.6-3
Table G.8-1

Uncertain MACCS Parameter Groups Used in the SOARCA
Unmitigated Station Blackout Uncertainty Analyses ................................. E-78
Population-weighted Individual Latent Cancer Fatality Risk Statistics
Conditional on the Occurrence of a Long-Term Station Blackout for
Five Circular Areas Centered on the Peach Bottom Plant ........................ E-79
Individual Early Fatality Risk Statistics Conditional on the Occurrence
of a Long-Term Station Blackout for Five Circular Areas with Specified
Radii Centered on the Peach Bottom Plant .............................................. E-81
Summary of Conclusions ......................................................................... E-94
State Environmental Requirements for Air Quality Protection ................... F-14
State Environmental Requirements for Water Resources Protection ........ F-14
State Environmental Requirements for Waste Management and
Pollution Prevention ................................................................................. F-15
State Environmental Requirements for Emergency Planning and
Response ................................................................................................. F-16
State Environmental Requirements for Ecological Resources
Protection ................................................................................................. F-16
State Environmental Requirements for Historic and Cultural
Resources Protection ............................................................................... F-16
Federal, State, and Local Permits and Other Requirements for Air
Quality Protection ..................................................................................... F-17
Federal, State, and Local Permits and Other Requirements for Water
Resource Protection ................................................................................. F-17
Federal, State, and Local Permits and Other Requirements for Waste
Management and Pollution Prevention ..................................................... F-19
Federal, State, and Local Permits and Other Requirements for
Emergency Planning and Response ........................................................ F-19
Federal, State, and Local Permits and Other Requirements for
Ecological Resource Protection................................................................ F-20
Federal, State, and Local Permits and Other Requirements for
Historic and Cultural Resource Protection ................................................ F-21
Common Sources of Noise and Decibels Levels ........................................ G-6
Level I Ecoregions and Corresponding Level III Ecoregions That
Occur in the Vicinity of Operating U.S. Commercial Nuclear Power
Plants ....................................................................................................... G-13
Ecoregions in the Vicinity of Operating U.S. Commercial Nuclear
Power Plants ............................................................................................ G-16
Percent of Area Occupied by Wetland and Deepwater Habitats within
5 Miles of Operating Nuclear Power Plants .............................................. G-20
Definition of Regions of Influence at 12 Nuclear Plants ............................ G-26

NUREG-1437, Revision 2

xx

ACRONYMS, ABBREVIATIONS, AND CHEMICAL NOMENCLATURE
ADAMS
AEA
AEC
ALARA
APE

Agencywide Documents Access and Management System
Atomic Energy Act
U.S. Atomic Energy Commission
as low as is reasonably achievable
area of potential effects

BCG
BEIR
BMP
BTA
Btu
BWR

Biota Concentration Guide
Biological Effects of Ionizing Radiation (National Research Council
Committee)
best management practice
best technology available
British thermal unit(s)
boiling water reactor

CAA
CCS
CDC
CDF
CEQ
CFR
CH4
CO
CO2
CO2e
CWA

Clean Air Act
cooling canal system
Centers for Disease Control and Prevention
core damage frequency
Council on Environmental Quality
Code of Federal Regulations
methane
carbon monoxide
carbon dioxide
carbon dioxide equivalent
Clean Water Act

dB
dBA
DOE
DPS
DSM

decibel(s)
A-weighted decibel(s)
U.S. Department of Energy
distinct population segment
demand-side management

EFH
EI
EIA
EIS
EMF
EPA
EPRI
EPU
ESA

essential fish habitat
exposure index
Energy Information Administration
environmental impact statement
electromagnetic field
U.S. Environmental Protection Agency
Electric Power Research Institute
extended power uprate
Endangered Species Act

xxi

NUREG-1437, Revision 2

Acronyms, Abbreviations, and Chemical Nomenclature
FLEX
FPRA
FR
FWS

flexible coping strategies
fire probabilistic risk assessment
Federal Register
U.S. Fish and Wildlife Service

GEIS
GHG
gpm
GTCC
GWd
GWd/MT

generic environmental impact statement
greenhouse gas
gallon(s) per minute
greater-than-Class C
gigawatt day(s)
gigawatt-days (units of energy) per metric tonne

H2O
HAPCs
HLW
hr
Hz

water; water vapor
habitat areas of particular concern
high-level waste
hour(s)
hertz

ICRP
IM&E
initial LR
IPE
IPEEE
ISFSI

International Commission on Radiological Protection
impingement mortality and entrainment
initial license renewal
Individual Plant Examination
Individual Plant Examination of External Events
independent spent fuel storage installation

km
kV
kW
kWh

kilometer(s)
kilovolt(s)
kilowatt(s)
kilowatt-hour(s)

L
LAR
lb
LCF
LERF
LLW
Ln
LOOP
lpm
LR GEIS
LWR

liter(s)
license amendment request
pound(s)
latent cancer fatality
large early release frequency
low-level (radioactive) waste
statistical sound level
loss of offsite power
liter(s) per minute
Generic Environmental Impact Statement for License Renewal of Nuclear
Plants
light water reactor

m
m2
m3

meter(s)
square meter(s)
cubic meter(s)

NUREG-1437, Revision 2

xxii

Acronyms, Abbreviations, and Chemical Nomenclature
m3/s
mA
MACCS
MCR
MEI
mG
mg
mg/L
Mgd
mGy
MHz
mi
min
mL
MLd
MMBtu
MPa
mph
mrad
mrem
MSA
mSv
MT
MTHM
MTU
MW
MWe
MWt
MWh

cubic meter(s) per second
milliampere(s)
MELCOR Accident Consequence Code System
main cooling reservoir
maximally exposed individual
milligauss
milligram(s)
milligram(s) per liter
million gallons per day
milligray(s)
megahertz
mile(s)
minute(s)
milliliter(s)
million liters per day
million Btu
megapascal(s)
mile(s) per hour
millirad(s)
millirem(s)
Magnuson-Stevens Fishery Conservation and Management Act
millisievert(s)
metric ton/tonne(s)
metric tonne(s) of heavy metal
metric tonne(s) of uranium
megawatt(s)
megawatt(s) electric
megawatt(s) thermal
megawatt-hour(s)

NAAQS
NEPA
NGCC
NHPA
NMFS
NMSA
NO
NO2
NOAA
NOx
NPDES
NRC
NREL
NRHP
NTTF

National Ambient Air Quality Standards
National Environmental Policy Act of 1969
natural gas combined cycle
National Historic Preservation Act of 1966
National Marine Fisheries Service
National Marine Sanctuaries Act
nitrogen oxide
nitrogen dioxide
National Oceanic and Atmospheric Administration
nitrogen oxides
National Pollutant Discharge Elimination System
U.S. Nuclear Regulatory Commission
National Renewable Energy Laboratory
National Register of Historic Places
Near-Term Task Force

xxiii

NUREG-1437, Revision 2

Acronyms, Abbreviations, and Chemical Nomenclature
ONMS
OSHA

Office of National Marine Sanctuaries
Occupational Safety and Health Administration

pCi
pCi/L
PDR
PM
PM10
PM2.5
ppm
ppmv
ppt
PSHA
PRA
PSD
psi
PWR

picocurie(s)
picocuries per liter
population dose risk
particulate matter
particulate matter with a mean aerodynamic diameter of 10 μm or less
particulate matter with a mean aerodynamic diameter of 2.5 μm or less
part(s) per million
parts per million by volume
part(s) per thousand
probabilistic seismic hazard assessment
probabilistic risk assessment
prevention of significant deterioration
pound(s) per square inch
pressurized water reactor

QHO

quantitative health objective

RCRA
rem
REMP
ROW
RY

Resource Conservation and Recovery Act of 1976
roentgen-equivalent-man
Radiological Environmental Monitoring Program
right-of-way
reactor year

s
SAMA
SAMDA
SAMG
SBO
SCDF
scf
SEIS
SFP
SLR
SO2
SOARCA
SPRA
SRM
SST
Sv

second(s)
severe accident mitigation alternative
severe accident mitigation design alternative
severe accident management guideline
station blackout
seismic core damage frequency
standard cubic foot (feet)
supplemental environmental impact statement
spent fuel pool
subsequent license renewal
sulfur dioxide
state-of-the-art reactor consequence analysis
seismic probabilistic risk assessment
Staff Requirements Memorandum
siting source term
sievert(s)

T
TDS
TEDE

ton(s)
total dissolved solids
total effective dose equivalent

NUREG-1437, Revision 2

xxiv

Acronyms, Abbreviations, and Chemical Nomenclature
T/yr

ton(s) per year

UA
UCB
UF6
U.S.
USACE

uncertainty analysis
upper confidence bound
uranium hexafluoride
United States
U.S. Army Corps of Engineers

VOC

volatile organic compound

yr

year(s)

μCi
μGy

microcurie(s)
microgray(s)

xxv

NUREG-1437, Revision 2

SHORTENED NUCLEAR POWER PLANT NAMES
USED IN THIS REPORT
Arkansas
Beaver Valley
Braidwood
Browns Ferry
Brunswick
Byron
Callaway
Calvert Cliffs
Catawba
Clinton
Columbia
Comanche Peak
Cooper
Crystal River
Davis-Besse
Diablo Canyon
D.C. Cook
Dresden
Duane Arnold
Farley
Fermi
FitzPatrick
Fort Calhoun
Ginna
Grand Gulf
Harris
Hatch
Hope Creek
Indian Point
Kewaunee
LaSalle
Limerick
McGuire
Millstone
Monticello
Nine Mile Point
North Anna
Oconee
Oyster Creek
Palisades
Palo Verde
Peach Bottom

Arkansas Nuclear One
Beaver Valley Power Station
Braidwood Station
Browns Ferry Nuclear Plant
Brunswick Steam Electric Plant
Byron Station
Callaway Plant
Calvert Cliffs Nuclear Power Plant
Catawba Nuclear Station
Clinton Power Station
Columbia Generating Station
Comanche Peak Nuclear Power Plant
Cooper Nuclear Station
Crystal River Nuclear Power Plant
Davis-Besse Nuclear Power Station
Diablo Canyon Power Plant
Donald C. Cook Nuclear Plant
Dresden Nuclear Power Station
Duane Arnold Energy Center
Joseph M. Farley Nuclear Plant
Enrico Fermi Atomic Power Plant
James A. FitzPatrick Nuclear Power Plant
Fort Calhoun Station
R.E. Ginna Nuclear Power Plant
Grand Gulf Nuclear Station
Shearon Harris Nuclear Power Plant
Edwin I. Hatch Nuclear Plant
Hope Creek Generating Station
Indian Point Energy Center
Kewaunee Power Station
LaSalle County Station
Limerick Generating Station
McGuire Nuclear Station
Millstone Power Station
Monticello Nuclear Generating Plant
Nine Mile Point Nuclear Station
North Anna Power Station
Oconee Nuclear Station
Oyster Creek Nuclear Generating Station
Palisades Nuclear Plant
Palo Verde Nuclear Generating Station
Peach Bottom Atomic Power Station

xxvii

NUREG-1437, Revision 2

Shortened Nuclear Power Plant Names Used in This Report
Perry
Pilgrim
Point Beach
Prairie Island
Quad Cities
River Bend
Robinson
St. Lucie
Salem
San Onofre
Seabrook
Sequoyah
South Texas
Summer
Surry
Susquehanna
Three Mile Island
Turkey Point
Vermont Yankee
Vogtle
Waterford
Watts Bar
Wolf Creek

Perry Nuclear Power Plant
Pilgrim Nuclear Power Station
Point Beach Nuclear Plant
Prairie Island Nuclear Generating Plant
Quad Cities Nuclear Power Station
River Bend Station
H.B. Robinson Steam Electric Plant
St. Lucie Nuclear Plant
Salem Nuclear Generating Station
San Onofre Nuclear Generating Station
Seabrook Station
Sequoyah Nuclear Plant
South Texas Project Electric Generating Station
Virgil C. Summer Nuclear Station
Surry Power Station
Susquehanna Steam Electric Station
Three Mile Island, Unit 1
Turkey Point Nuclear Plant
Vermont Yankee Nuclear Power Station
Vogtle Electric Generating Plant
Waterford Steam Electric Station
Watts Bar Nuclear Plant
Wolf Creek Generating Station

NUREG-1437, Revision 2

xxviii

CONVERSION TABLE
Multiply

By

To Obtain

To Convert English to Metric Equivalents
acres (ac)
cubic feet (ft3)
cubic yards (yd3)
curies (Ci)
degrees Fahrenheit (F) -32
feet (ft)
gallons (gal)
gallons (gal)
inches (in.)
miles (mi)
pounds (lb)
rads
rems
short tons (tons)
short tons (tons)
square feet (ft2)
square yards (yd2)
square miles (mi2)
yards (yd)

0.4047
0.02832
0.7646
3.7  1010
0.5555
0.3048
3.785
0.003785
2.540
1.609
0.4536
0.01
0.01
907.2
0.9072
0.09290
0.8361
2.590
0.9144

hectares (ha)
cubic meters (m3)
cubic meters (m3)
becquerels (Bq)
degrees Celsius (C)
meters (m)
liters (L)
cubic meters (m3)
centimeters (cm)
kilometers (km)
kilograms (kg)
grays (Gy)
sieverts (Sv)
kilograms (kg)
metric tons/tonnes (MT)
square meters (m2)
square meters (m2)
square kilometers (km2)
meters (m)

To Convert Metric to English Equivalents
becquerels (Bq)
centimeters (cm)
cubic meters (m3)
cubic meters (m3)
cubic meters (m3)
degrees Celsius (C) +17.78
grays (Gy)
hectares (ha)
kilograms (kg)
kilograms (kg)
kilometers (km)
liters (L)
meters (m)
meters (m)
metric tons/tonnes (MT)
sieverts (Sv)
square kilometers (km2)
square meters (m2)
square meters (m2)

2.7  10-11
0.3937
35.31
1.308
264.2
1.8
100
2.471
2.205
0.001102
0.6214
0.2642
3.281
1.094
1.102
100
0.3861
10.76
1.196

curies (Ci)
inches (in.)
cubic feet (ft3)
cubic yards (yd3)
gallons (gal)
degrees Fahrenheit (F)
rads
acres
pounds (lb)
short tons (tons)
miles (mi)
gallons (gal)
feet (ft)
yards (yd)
short tons (tons)
rems
square miles (mi2)
square feet (ft2)
square yards (yd2)

xxix

NUREG-1437, Revision 2

EXECUTIVE SUMMARY
The Atomic Energy Act of 1954 authorizes the U.S. Nuclear Regulatory Commission (NRC) to
issue licenses to operate commercial nuclear power plants for up to 40 years and permits the
renewal of these licenses. By regulation, the NRC is allowed to renew these licenses for up to
an additional 20 years, depending on the outcome of safety and environmental reviews. There
are no specific limitations in the Atomic Energy Act or the NRC’s regulations restricting the
number of times a license may be renewed.
NRC regulations in Title 10 of the Code of Federal Regulations Section 54.17(c) (10 CFR
54.17(c)) allow a license renewal application to be submitted within 20 years of license
expiration, and NRC regulations at 10 CFR 54.31(b) specify that a renewed license will be for a
term of up to 20 years plus the length of time remaining on the current license. As a result,
renewed licenses may be for a term of up to 40 years.
The license renewal process is designed to ensure safe operation of the nuclear power plant
and protection of the environment during the license renewal term. Under the NRC’s
environmental protection regulations in 10 CFR Part 51, which implements Section 102(2) of the
National Environmental Policy Act (NEPA), the renewal of a nuclear power plant operating
license requires an analysis of the environmental effects (impacts) of the action and the
preparation of an environmental impact statement (EIS).
To support the preparation of license renewal EISs, the NRC conducted a comprehensive
review to identify the environmental effects of license renewal. The review determined which
environmental effects could result in the same or similar (generic) impact at all nuclear power
plants or a specific subset of plants, and which effects could result in different levels of impact,
requiring nuclear power plant-specific analyses for an impact determination. The review
culminated in the issuance of the Generic Environmental Impact Statement for License Renewal
of Nuclear Plants (LR GEIS), NUREG-1437, in May 1996, followed by the publication of the final
rule that codified the LR GEIS findings on June 5, 1996 (61 Federal Register [FR] 28467).1
The 1996 LR GEIS2 improved the efficiency of the license renewal environmental review
process by (1) identifying and evaluating all of the environmental effects that may occur when
renewing commercial nuclear power plant operating licenses, (2) identifying and evaluating the
environmental effects that are expected to be generic (the same or similar) at all nuclear plants
or a specific subset of plants, and (3) defining the number and scope of the environmental
effects that need to be addressed in nuclear power plant-specific EISs. For the issues that
cannot be evaluated generically, the NRC conducts nuclear power plant-specific (hereafter
called plant-specific) environmental reviews and prepares plant-specific supplemental EISs
(SEISs) to the LR GEIS. The generic environmental findings in the LR GEIS are applicable to
the 20-year license renewal increment plus the number of years remaining on the current
license, up to a maximum of 40 years.
The 1996 final rule codified the findings of the 1996 LR GEIS into regulations at 10 CFR
Part 51, Appendix B to Subpart A, “Environmental Effect of Renewing the Operating License of
1

Final rules were also issued on December 18, 1996 (61 FR 66537), and September 3, 1999
(64 FR 48496).
2
Any reference to the 1996 LR GEIS includes the two-volume set published in May 1996 and
Addendum 1 to the LR GEIS published in August 1999.

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Executive Summary
a Nuclear Power Plant,” and Table B-1, “Summary of Findings on NEPA Issues for License
Renewal of Nuclear Power Plants” (61 FR 28467, June 5, 1996). As stated in the final rule, the
Commission recognized that environmental issues might change over time and that additional
issues may need to be considered. Based on this recognition, and as further stated in the rule
and in the introductory paragraph to Appendix B to Subpart A in Part 51 of the regulations, the
Commission intends to review the material in Appendix B, including Table B-1 and the
underlying LR GEIS, on a 10-year basis, and update it if necessary.
Subsequently, the NRC completed its first 10-year review of the 1996 LR GEIS and Table B-1
on June 20, 2013. That review of the LR GEIS considered lessons learned and knowledge
gained from completed license renewal environmental reviews since 1996. The updated
LR GEIS, Revision 1, and final rule (78 FR 37282), including Table B-1, redefined the number
and scope of the NEPA issues that must be addressed in license renewal environmental
reviews.
The NRC began the second 10-year review on August 4, 2020, by publishing a notice of intent
to review and potentially update the LR GEIS approximately 7 years after the last revision cycle
(see 85 FR 47252). For further information regarding the review and update of this LR GEIS see
Section 1.6. As part of this review and update, the following activities occurred:
•

NRC staff conducted a series of public scoping meetings in August 2020 (see 85 FR 47252
for more details). The scoping period concluded on November 2, 2020.

•

NRC staff submitted a rulemaking plan in July 2021 requesting Commission approval to
initiate a rulemaking to amend Table B-1 and update the LR GEIS and associated guidance.

•

In February 2022, the Commission directed the NRC staff to develop a new rulemaking plan
that would update the LR GEIS to fully account for subsequent license renewal (SLR) in light
of recent Commission adjudicatory decisions.

•

NRC staff submitted a revised rulemaking plan in March 2022.

•

In April 2022, the Commission approved the staff’s recommendation to proceed with the
rulemaking.

•

NRC staff submitted the proposed rule package and draft revised LR GEIS to the
Commission for its review on December 6, 2022.

•

On January 23, 2023, the Commission approved publication of the proposed rule in the
Federal Register for a 60-day comment period.

•

NRC staff published the proposed rule, draft LR GEIS, and associated guidance for public
comment in the Federal Register on March 3, 2023 (88 FR 13329).

•

NRC staff conducted a series of public meetings in March and April 2023 to take comment
on the proposed rule package.

The revisions to the LR GEIS are based on the consideration of (1) comments received from the
public during the public scoping period, (2) a review of comments received on plant-specific
SEISs, (3) lessons learned and knowledge gained from previously completed and ongoing initial
license renewal (initial LR) and SLR environmental reviews, (4) Commission direction, and
(5) comments received from the public and other stakeholders on the draft LR GEIS and
proposed rule. In addition, new scientific research, public comments, changes in environmental
regulations and impacts methodology, and other new information were considered in evaluating

NUREG-1437, Revision 2

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Executive Summary
the potential impacts associated with nuclear power plant continued operations and
refurbishment during the initial LR term or SLR.
Changes made in response to comments in this final LR GEIS, as well as changes made to
include updated information, corrections, and substantial editorial revisions, are marked with a
change bar (vertical line) on the side margin of the page where the changes or additions were
made. Minor editorial revisions and those limited to formatting are not marked. The NRC also
made several targeted text changes that are not marked, which included the removal of
duplicative text and organizational changes to this LR GEIS to address changes to NEPA from
the Fiscal Responsibility Act of 2023.
The purpose of the review for this LR GEIS was to determine if the findings presented in the
2013 LR GEIS remain valid for initial LR and support the scope of license renewal, consider
whether those findings also apply to SLR, and to update or revise those findings as appropriate.
When conducting a thorough update to the LR GEIS that reflects the “hard look” that is required
for a NEPA document, the NRC considered changes in applicable laws and regulations, new
data in its possession from scientific literature and nuclear power plant operations, collective
experience, and lessons learned and knowledge gained from conducting initial LR and SLR
environmental reviews since development of the 2013 LR GEIS. The NRC also considered
comments received on the draft LR GEIS and proposed rule (see Section 1.10) in finalizing this
LR GEIS. As a result of the NRC’s review and update, the NRC identified 80 environmental
issues for inclusion in revised Table B-1. They include 59 issues which were determined to be
same or similar impact at all nuclear power plants or a specific subset of plants (i.e., generic
issues, Category 1); 20 issues which require a plant-specific analysis (Category 2); and one
issue that remains uncategorized.

ES.1 Purpose and Need for the Proposed Action
The proposed action is the renewal of commercial nuclear power plant operating licenses. A
renewed license is just one of a number of conditions that licensees must meet to be allowed to
continue to operate the nuclear power plant during the renewal term.
The purpose and need for the proposed action (license renewal) is to provide an option that
allows for baseload power generation capability beyond the term of the current nuclear power
plant operating license to meet future system generating needs, as such needs may be
determined by State, utility, system, and, where authorized, Federal (other than NRC)
decisionmakers. Except to the extent that findings in the safety review required by the Atomic
Energy Act or in the environmental review could lead the NRC to not renew the operating
license, the NRC has no role in the energy-planning decisions of power plant owners, State
regulators, system operators, and, in some cases, other Federal agencies as to whether the
nuclear power plant should continue to operate.
In addition, the NRC has no authority or regulatory control over the ultimate selection of
replacement energy alternatives. The NRC also cannot ensure the selection of environmentally
preferable replacement power alternatives. While a range of reasonable replacement energy
alternatives are discussed in the LR GEIS, and evaluated in detail in plant-specific supplements
to the LR GEIS, the only alternative to license renewal within NRC’s decisionmaking authority is
to not renew the operating license. The environmental impacts of not renewing the operating
license are addressed under the no action alternative.

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NUREG-1437, Revision 2

Executive Summary
At some point, all nuclear power plants will terminate reactor operations and begin the
decommissioning process. Under the no action alternative, reactor operations would be
terminated at or before the end of the current operating license. The no action alternative, unlike
the other alternatives, does not expressly meet the purpose and need of the proposed action
(license renewal), because it does not provide an option for energy-planning decisionmakers in
meeting future electric power system needs. No action, on its own, would likely create a need
for replacement power, energy conservation and efficiency (demand-side management),
purchasing power from outside the region, or some combination of these options. Thus, a range
of reasonable replacement energy alternatives is described in the LR GEIS, including fossil fuel,
new nuclear, and renewable energy sources. Conservation and power purchasing are also
considered as replacement energy alternatives to license renewal because they represent other
options for electric power system planners.

ES.2 Development of the Revised Generic Environmental Impact Statement
This LR GEIS documents the results of the systematic approach the NRC used to evaluate the
environmental effects (impacts) of renewing the operating licenses of commercial nuclear power
plants. The environmental consequences of both initial LR and SLR include (1) impacts
associated with continued operations and any refurbishment activities similar to those that have
occurred during the current license term; (2) impacts of various alternatives to the proposed
action; (3) impacts from the termination of nuclear power plant operations and decommissioning
after the license renewal term (with emphasis on the incremental effect caused by an additional
20 years of operation); (4) impacts associated with the uranium fuel cycle; (5) impacts of
postulated accidents; (6) cumulative effects of the proposed action; and (7) resource
commitments associated with the proposed action, including unavoidable adverse impacts,
relationship between short-term use and long-term productivity, and irreversible and irretrievable
commitment of resources. The LR GEIS also discusses the impacts of various reasonable
alternatives to the proposed action (initial LR or SLR). The environmental consequences of
these activities are discussed in the LR GEIS.
In a notice of intent published in the Federal Register on August 4, 2020 (85 FR 47252), the
NRC notified the public of its preliminary analysis and plan to review and potentially revise the
LR GEIS, including to address SLR, and to provide an opportunity to participate in the
environmental scoping process. The NRC held four public webinars in August 2020 to support
public participation in the LR GEIS revision. The NRC staff issued a scoping summary report in
June 2021.
In evaluating the impacts of the proposed action (license renewal) and considering comments
received during the scoping and public comment periods, new and updated technical and
regulatory information, as well as Commission direction, the NRC identified 80 environmental
issues: 72 environmental issues were associated with continued operations, refurbishment, and
other supporting activities; 2 with postulated accidents; 1 with termination of plant operations
and decommissioning; 4 with the uranium fuel cycle; and 1 with cumulative effects (impacts).
For all of these issues, the incremental effect of license renewal was the focus of the evaluation.
For each environmental issue, the revised LR GEIS (1) describes the nuclear power plant
activity or operational aspect during the initial LR or SLR term that could affect the resource;
(2) identifies the resource that is affected; (3) evaluates past license renewal reviews and other
available information, including information related to impacts during a SLR term; (4) assesses
the nature and magnitude of the environmental effect (impact) from initial LR or SLR on the
affected resource; (5) characterizes the significance of the effect; (6) determines whether the

NUREG-1437, Revision 2

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Executive Summary
results of the analysis apply to all or a specific subset of nuclear power plants (i.e., whether the
environmental issue is Category 1, Category 2, or uncategorized); and (7) considers additional
mitigation measures for reducing adverse impacts.
The scope of the revised LR GEIS also discusses a range of alternatives to license renewal,
including replacement power generation (using fossil fuels, new nuclear, and renewables),
energy conservation and efficiency (demand-side management), and purchased power. It also
evaluates the impacts from the no action alternative (not renewing the operating license). This
LR GEIS includes the NRC’s evaluation of construction, operation, postulated accidents,
decommissioning, and fuel cycles for replacement energy alternatives.
Together with publication of the proposed rule, the NRC issued the draft LR GEIS for public
comment. This LR GEIS provides the technical basis for the Commission’s license renewal
regulations in 10 CFR Part 51, including for the 80 identified environmental issues associated
with continued operation and refurbishment of nuclear power plants during a license renewal
term. In the proposed rule, the NRC sought comment on whether the scope of the rule,
including the scope and applicability of Table B-1 of 10 CFR Part 51, should be expanded
beyond two license renewal terms. The NRC also issued for public comment associated
guidance documents, including draft Revision 2 (DG-4027) of Regulatory Guide 4.2,
Supplement 1, and draft Revision 2 to NUREG-1555, Supplement 1.
The public comment period ran from March 3, 2023, to May 2, 2023. The NRC received 1,889
comment submissions (i.e., letters, emails, and other documents), which the NRC posted to the
Regulations.gov website. During the public comment period, the NRC held six hybrid public
meetings, which were transcribed. The NRC also conducted an informational meeting with
Federally recognized Tribes on April 19, 2023, to afford Tribal representatives the opportunity to
discuss the rule with the staff. All comment submissions, including those received in writing and
those provided at the public meetings, were considered in preparing this LR GEIS. The NRC’s
responses to all comments are provided in Appendix A.2 of this LR GEIS.

ES.3 Impact Definitions and Categories
The NRC’s environmental impact standard considers Council on Environmental Quality
terminology, including Council on Environmental Quality revisions in Part 1501—NEPA and
Agency Planning (40 CFR Part 1501) and Part 1508—Definitions (40 CFR 1508; 89 FR 35442).
In determining whether the incremental environmental effects (impacts) of the proposed action
(license renewal—either initial LR or SLR) are significant, the NRC analyzes the context (i.e.,
geographic area and resources) and intensity of the effects. The geographic area consists of the
characteristics of the area and its resources, such as proximity to unique or sensitive resources
or communities with environmental justice concerns. For nuclear power plant-specific
environmental issues, significance depends on the effects in the relevant geographic area,
including but not limited to consideration of short- and long-term effects, as well as beneficial
and adverse effects.
Based on this, the NRC has established three significance levels for potential impacts: SMALL,
MODERATE, and LARGE. The three significance levels, presented in a footnote to Table B-1 of
10 CFR Part 51, Appendix B to Subpart A, are defined as follows:
•

SMALL: Environmental effects are not detectable or are so minor that they will neither
destabilize nor noticeably alter any important attribute of the resource. For the purposes of

xxxv

NUREG-1437, Revision 2

Executive Summary
assessing radiological impacts, the Commission has concluded that those impacts that do
not exceed permissible levels in the Commission’s regulations are considered SMALL.
•

MODERATE: Environmental effects are sufficient to alter noticeably, but not to destabilize,
important attributes of the resource.

•

LARGE: Environmental effects are clearly noticeable and are sufficient to destabilize
important attributes of the resource.

In addition to evaluating the impacts for each environmental issue, the NRC also determined
whether the analysis in the LR GEIS could be applied to all nuclear power plants or plants with
specified design or site characteristics. Issues were assigned Category 1 (i.e., generic issues
and applicable to all or a specific subset of nuclear plants) or Category 2 (i.e., requiring a plantspecific analysis), as further described in Section 1.5.2.3 of this LR GEIS.

ES.4 Affected Environment
For purposes of the evaluation in this LR GEIS revision, the “affected environment” is the
environment currently existing at and around operating commercial nuclear power plants.
Current conditions in the affected environment are the result of past construction and ongoing
operations at the plants, as well as reasonably foreseeable environmental trends. The NRC has
considered the effects of these past and ongoing impacts and how they have shaped the
environment. The NRC evaluated impacts of license renewal that are incremental to existing
conditions. These existing conditions serve as the baseline for the evaluation and include the
effects of past and present actions at the nuclear power plant sites and vicinity. This existing
affected environment comprises the environmental baseline against which potential
environmental impacts of license renewal are evaluated.
In the LR GEIS, the NRC describes the affected environment in terms of the following resource
areas or subject matter areas: (1) description of nuclear power plant facilities and operations;
(2) land use and visual resources; (3) meteorology, air quality, and noise; (4) geologic
environment; (5) water resources (surface water and groundwater resources); (6) ecological
resources (terrestrial resources, aquatic resources, and federally protected ecological
resources); (7) historic and cultural resources; (8) socioeconomics; (9) human health
(radiological and nonradiological hazards and postulated accidents); (10) environmental justice;
(11) waste management and pollution prevention (radioactive and nonradioactive waste); and
(12) greenhouse gas emissions and climate change. The affected environment of the operating
plant sites represents diverse environmental conditions.

ES.5 Impacts from Continued Operations and Refurbishment Activities
Associated with License Renewal (Initial or Subsequent)
The NRC identified 80 environmental issues related to continued operations and refurbishment
associated with both initial LR or SLR. Twenty of the issues were identified as Category 2
issues and would require plant-specific evaluations in future SEISs. Fifty-nine issues have been
evaluated and determined to be generic to all nuclear power plants or to a specific subset of
plants, and one issue remains uncategorized. The conclusions for each Category 1 or
Category 2 environmental issue are presented by resource area or subject matter. The
conclusions for each issue are summarized in Table 2.1-1. Chapter 4 provides the NRC’s
detailed analysis of and technical basis for each issue and supports the finding codified in
Table B-1 of Appendix B to Subpart A of 10 CFR Part 51.

NUREG-1437, Revision 2

xxxvi

Executive Summary

ES.6 Comparison of Alternatives
This LR GEIS evaluates the impacts of the proposed action (license renewal) and describes a
range of alternatives to license renewal, including the no action alternative (not renewing the
operating license). It also evaluates the impacts of replacement energy alternatives (fossil fuel,
new nuclear, and renewables), energy conservation and efficiency (demand-side management),
and purchased power. The impacts of renewing the operating license of a nuclear power plant
are comparable to the impacts of replacement energy alternatives. Replacement energy
alternatives could require the construction of a new power plant and/or modification of the
electric transmission grid. New power plants would also have operational impacts. Conversely,
license renewal does not require new construction and operational impacts beyond what is
already being experienced. Other alternatives not requiring construction or causing operational
impacts include energy conservation and efficiency (demand-side management), delayed
retirement, repowering, and purchased power.
Under NEPA, the NRC has an obligation to consider reasonable alternatives to the proposed
action (license renewal). The LR GEIS facilitates that analysis by providing NRC review teams
with environmental information related to the range of reasonable replacement energy
alternatives as of the time this LR GEIS was prepared. A plant-specific analysis of replacement
energy alternatives will be performed for each SEIS, taking into account changes in technology
and science since the preparation of this LR GEIS.

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1

INTRODUCTION

The Atomic Energy Act (AEA) of 1954 (42 U.S.C. § 2011 et seq.) authorizes the U.S. Nuclear
Regulatory Commission (NRC) to issue licenses to operate commercial nuclear power plants for
up to 40 years. The 40-year length of the original license period was imposed for economic and
antitrust reasons rather than the technical limitations of the nuclear power plant. NRC
regulations allow for the renewal of these licenses for up to an additional 20 years, depending
on the outcome of an assessment determining whether the nuclear power plant can continue to
operate safely and protect the environment during the 20-year period of extended operation.
There are no specific limitations in the AEA or the NRC’s regulations restricting the number of
times a license may be renewed.
The NRC’s regulations in Title 10 of the Code of Federal Regulations (10 CFR) Section 54.17(c)
allow a license renewal application to be submitted within 20 years of license expiration, and the
NRC’s regulations at 10 CFR 54.31(b) specify that a renewed license will be for a term of up to
20 years plus the length of time remaining on the current license. As a result, renewed licenses
may be for a term of up to 40 years.
Contents of Chapter 1
• Purpose of the LR GEIS (Section 1.1)
• Description of the Proposed Action (Section 1.2)
• Purpose and Need for the Proposed Action (Section 1.3)
• Alternatives to the Proposed Action (Section 1.4)
• Analytical Approach Used in the LR GEIS (Section 1.5)
• Scope of the LR GEIS Revision (Section 1.6)
• Decisions to Be Supported by the LR GEIS (Section 1.7)
• Implementation of the Rule (Section 1.8)
• Public Scoping Comments on the LR GEIS Update (Section 1.9)
• Public Comments on the Draft LR GEIS (Section 1.10)
• Lessons Learned (Section 1.11)
• Organization of the LR GEIS (Section 1.12)
The license renewal process is designed to ensure the safe operation of the nuclear power plant
and protection of the environment during the license renewal term. Under the NRC’s regulations
in 10 CFR Part 51, “Environmental Protection Regulations for Domestic Licensing and Related
Regulatory Functions”, which implement Section 102(2) of the National Environmental Policy
Act (NEPA; 42 U.S.C. § 4321 et seq.), the renewal of a nuclear power plant operating license
requires an analysis of the environmental effects (impacts) of the proposed action and the
preparation of an environmental impact statement (EIS).
To support the preparation of license renewal EISs, the NRC conducted a comprehensive
review to identify the environmental effects of license renewal. The review determined which
environmental effects could result in the same or similar (generic) impact at all nuclear power
1-1

NUREG-1437, Revision 2

Introduction
plants or a specific subset of plants and which effects could result in different levels of impact,
requiring nuclear plant-specific analyses for an impact determination. The review culminated in
the issuance of NUREG-1437, Generic Environmental Impact Statement for License Renewal of
Nuclear Plants (LR GEIS), in May 1996, followed by the publication of the final rule that codified
the LR GEIS findings on June 5, 1996 (61 Federal Register [FR] 284671; NRC 1996,
NRC 1999b).
The 1996 LR GEIS2 improved the efficiency of the license renewal environmental review
process by (1) identifying and evaluating all of the environmental effects that may occur when
renewing commercial nuclear power plant operating licenses, (2) identifying and evaluating the
environmental effects that are expected to be generic (the same or similar) at all nuclear power
plants or a specific subset of plants, and (3) defining the number and scope of the
environmental effects that need to be addressed in nuclear power plant-specific EISs. For the
issues that could not be evaluated generically, the NRC would conduct nuclear power plantspecific (hereafter called plant-specific) environmental reviews and prepare plant-specific
supplemental EISs (SEISs) to the LR GEIS. The generic environmental findings in this LR GEIS
are applicable to the 20-year license renewal increment, either an initial license renewal
(initial LR) term or the first subsequent license renewal (SLR) term, plus the number of years
remaining on the current license, up to a maximum of 40 years.
Generic Environmental Impact Statement
A GEIS is an EIS that assesses the scope and impact of the environmental effects that would
be associated with an action (such as license renewal) at numerous sites.

1.1

Purpose of the LR GEIS

This LR GEIS documents the results of the systematic approach the NRC used to evaluate the
incremental environmental effects (impacts) of renewing the operating licenses of commercial
nuclear power plants. The LR GEIS also provides the technical basis for the Commission’s
license renewal regulations in 10 CFR Part 51. In the 1996 LR GEIS and related rulemaking, the
Commission determined that certain impacts associated with the renewal of a nuclear power
plant operating license were the same or similar for all plants or specific subset of plants and
could be treated on a generic basis. In this way, repetitive reviews of these impacts could be
avoided. The Commission based its generic assessment of certain environmental impacts on
the following factors:
• License renewal will involve nuclear power plants for which the environmental impacts of
operation are well understood as a result of lessons learned and knowledge gained from
operating experience and completed license renewals.
• Activities associated with license renewal are expected to be within this range of
environmental operating experience; thus, environmental impacts can be reasonably
predicted.
• Changes in the environment around nuclear power plants are gradual and predictable.

1

Final rules were also issued on December 18, 1996 (61 FR 66537) and September 3, 1999
(64 FR 48496).
2 Any reference in this document to the 1996 LR GEIS includes the two-volume set published in
May 1996 (NRC 1996) and Addendum 1 to the LR GEIS published in August 1999 (NRC 1999b).

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The LR GEIS is intended to improve the efficiency of the license renewal environmental review
process by (1) providing an evaluation of the types of environmental impacts that may occur
from initial LR of commercial nuclear power plant operating licenses or SLR (specifically limited
to one term of SLR), (2) identifying and assessing impacts that are expected to be generic
(the same or similar) at all nuclear plants (or plants with specified plant or site characteristics),
and (3) defining the number and scope of environmental issues that need to be addressed in
plant-specific SEISs. The LR GEIS also provides information that aids in the preparation of
plant-specific SEISs.

1.2

Description of the Proposed Action

The NRC’s environmental regulations in 10 CFR 51.20, require the preparation of an EIS to
address the impacts of the proposed action of renewing a plant’s operating license. The EIS
requirements for a plant-specific license renewal review are specified in 10 CFR 51.71 and
51.95. The NRC’s public health and safety and other technical requirements for the renewal of
operating licenses are found in 10 CFR Part 54. Part 54 requires applicants to perform safety
evaluations and assessments of nuclear power plants and provide the NRC with sufficient
information to analyze the impacts of continued operation for the requested license renewal
term. Applicants are required to assess the effects of aging on passive and long-lived systems,
structures, and components.
The Proposed Action
To renew commercial nuclear power plant operating licenses.
Purpose and Need for the Proposed Action
To provide an option that allows for baseload power generation capability beyond the term of
the current nuclear power plant operating license to meet future system generating needs.
Most nuclear power plant licensees (either a public utility or non-utility plant owner) are
expected to begin preparation for license renewal about 10 to 20 years before expiration of their
current operating licenses. Inspection, surveillance, testing, and maintenance programs to
support continued nuclear power plant operations during the license renewal term would be
integrated gradually over a period of years. Any refurbishment-type activities undertaken for the
purposes of license renewal have generally been completed during normal plant refueling or
maintenance outages before the original license term expires. Activities associated with license
renewal and operation of a nuclear power plant for an additional 20 years are discussed in
Chapter 2.

1.3

Purpose and Need for the Proposed Action

The Commission acts on each application submitted by a licensee for the renewal of
commercial nuclear power plant operating licenses per Section 103 of the AEA. A renewed
license is just one of several conditions that each licensee must meet to operate its nuclear
power plant during the license renewal term. State regulators, system operators, and, in some
cases, other Federal agencies, ultimately decide whether the nuclear power plant will continue
to operate based on factors such as need for power or other factors within the State’s
jurisdiction or owner’s control. Economic considerations play a primary role in this decision.

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The purpose and need for the proposed action (issuance of a renewed license) is to provide an
option that allows for baseload power generation capability beyond the term of the current
nuclear power plant operating license to meet future system generating needs. Such needs may
be determined by other energy-planning decisionmakers, such as State, utility, and, where
authorized, Federal agencies (other than the NRC). Except to the extent that findings in the
safety review required by the AEA or the NEPA environmental review that could lead the NRC
to reject a license renewal application, the NRC does not have a role in the energy-planning
decisions about whether a particular nuclear power plant should continue to operate.
From the perspective of the licensee and the State regulatory authority, the purpose of renewing
an operating license is to maintain the availability of the nuclear power plant to meet system
energy requirements beyond the term of the plant’s current license. In cases of interstate
generation or other special circumstances, Federal agencies such as the Federal Energy
Regulatory Commission or the Tennessee Valley Authority may be involved in making these
decisions.

1.4

Alternatives to the Proposed Action

In plant-specific license renewal environmental reviews, the NRC considers the environmental
consequences of the proposed action, the no action alternative (i.e., not renewing the operating
license), and the environmental consequences of various alternatives for replacing or offsetting
the nuclear power plant’s generating capacity. No definitive conclusions are made in the
LR GEIS about the relative environmental consequences of license renewal, the no action
alternative, and the construction and operation of alternative facilities for generating electric
energy. However, information presented in the LR GEIS can be used by the NRC and
applicants in performing the plant-specific analysis of alternatives.
In plant-specific environmental reviews, the NRC compares the environmental impacts of
license renewal with those of the no action alternative and replacement energy alternatives to
“determine whether or not the adverse environmental impacts of license renewal are so great
that preserving the option of license renewal for energy planning decisionmakers would be
unreasonable” (10 CFR 51.95(c)(4)).

1.5
1.5.1

Analytical Approach Used in the LR GEIS
Objectives

The LR GEIS facilitates the NRC’s environmental review process by identifying and evaluating
environmental impacts that are considered generic and common to all or a specific subset of
nuclear power plants. Plant-specific environmental issues will be addressed in separate SEISs
to the LR GEIS. The NRC staff will examine potentially new and significant information with
respect to generic impact conclusions in plant-specific SEISs.
1.5.2

Methodology

Environmental effects (impacts) of license renewal and the resources that could be affected by
continued operation and any refurbishment undertaken for the purposes of license renewal were
identified. The NRC used the following general analytical approach to identify and evaluate
potential environmental issues and the impacts associated with continued operations and any
refurbishment: (1) describe the nuclear power plant activity or aspect of plant operations or
refurbishment that could affect the resource; (2) identify the resource that is affected;

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(3) evaluate past license renewal reviews and other available information, including information
related to impacts during a SLR term; (4) assess the nature and magnitude of the environmental
effect (impact) from initial LR or SLR on the affected resource; (5) characterize the significance
of the effect; (6) determine whether the results of the analysis apply to all or a specific subset of
nuclear power plants (i.e., whether the environmental issue is Category 1 or Category 2, as
described below); and (7) consider additional mitigation measures for reducing adverse impacts.
Environmental issues were identified in an iterative manner rather than a stepwise manner.
For example, after information was collected and levels of significance were reviewed,
environmental issues and their associated impacts were reexamined to determine if any issues
should be removed, added, consolidated, or divided.
1.5.2.1

Defining Environmental Issues

The NRC updated the LR GEIS in 2013. The 2013 LR GEIS presents the findings of a
systematic inquiry into the environmental impacts of license renewal resulting in the
identification of 78 environmental issues (or impacts). Public and stakeholder comments on
previous plant-specific license renewal reviews were analyzed to evaluate the existing
environmental issues and identify new issues. As a result, the NRC considered the need to
modify, add to, group, subdivide, or delete any of the 78 environmental issues evaluated in the
2013 LR GEIS. In this revised LR GEIS, the NRC has evaluated 80 environmental issues.
1.5.2.2

Collecting Information

Information, including lessons learned and knowledge gained, from license renewal
environmental reviews performed since development of the 2013 LR GEIS was collected and
reviewed (see also Section 1.11). Searches of the open scientific literature, databases, and
websites were conducted for each resource area. This information was collected and evaluated
to determine if the environmental issues and findings in the 2013 LR GEIS needed to be revised
for initial LR and to update those findings to apply to SLR.
1.5.2.3

Impact Definitions and Categories

The NRC’s environmental impact standard considers Council on Environmental Quality (CEQ)
terminology, including CEQ revisions in Part 1501—NEPA and Agency Planning (40 CFR
Part 1501) and Part 1508—Definitions (40 CFR Part 1508; 89 FR 35442). CEQ requires that
agencies examine both the context of an action and the intensity of the effects in making a
significance determination as to the adverse effect of the proposed action.
In determining whether the incremental environmental effects (impacts) of the NRC’s proposed
action (license renewal – either initial LR or SLR) are significant, the NRC considers the action
in several contexts. The NRC’s analysis of context considers the characteristics of the
geographic area and its resources, such as proximity to unique or sensitive resources or
communities with environmental justice concerns. For nuclear power plant-specific
environmental issues, significance depends on the effects in the relevant geographic area,
including, but not limited to, consideration of short- and long-term effects, as well as beneficial
and adverse effects. The NRC’s analysis of the intensity of effects considers the degree to
which the proposed action may (1) adversely affect public health and safety; (2) adversely affect
unique characteristics of the geographic area such as historic or cultural resources, parks, Tribal
sacred sites, prime farmlands, wetlands, wild and scenic rivers, or ecologically critical areas;
(3) violate relevant Federal, State, Tribal, or local laws or other requirements or be inconsistent
with Federal, State, Tribal, or local laws or other requirements or be inconsistent with Federal,

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State, Tribal, or local policies designed for the protection of the environment; (4) have potential
effects on the human environment that are highly uncertain; (5) adversely affect resources listed
or eligible for listing in the National Register of Historic Places; (6) adversely affect an
endangered or threatened species or its habitat, including habitat that has been determined to
be critical under the Endangered Species Act of 1973 (16 U.S.C. § 1531 et seq.); (7) adversely
affect communities with environmental justice concerns; and (8) adversely affect rights of Tribal
Nations that have been reserved through treaties, statutes, or Executive Orders (40 CFR
1501.3(d)).
Based on this, the NRC has established three significance levels for potential impacts: SMALL,
MODERATE, and LARGE. The three significance levels, presented in a footnote to Table B–1 in
Appendix B to Subpart A of 10 CFR Part 51, are defined as follows:
• SMALL – environmental effects are not detectable or are so minor that they will neither
destabilize nor noticeably alter any important attribute of the resource. For the purposes of
assessing radiological impacts, the Commission has concluded that those impacts that do not
exceed permissible levels in the Commission’s regulations are considered SMALL.
• MODERATE – environmental effects are sufficient to alter noticeably, but not to destabilize,
important attributes of the resource.
• LARGE – environmental effects are clearly noticeable and are sufficient to destabilize
important attributes of the resource.
These levels are used for describing the environmental impacts of the proposed action as well
as for the impacts of a range of reasonable alternatives3 to the proposed action.
Resource-specific effects or impact definitions from applicable environmental laws and
executive orders, other than SMALL, MODERATE, and LARGE, are used where appropriate.
For issues in which the probability of occurrence is a key consideration (i.e., postulated
accidents), the probability of occurrence has been factored into the impact determination.
Mitigation measures that could be used to avoid, minimize, rectify, reduce, eliminate, or
compensate for adverse impacts are discussed where appropriate.
In addition to evaluating the impacts for each environmental issue, a determination is also made
for each issue about whether the environmental analysis in the LR GEIS could be applied to all
nuclear power plants or plants with specified design or site characteristics. Based on the
applicability of the impact analysis, each issue is assigned either Category 1 or Category 2.
These categories are defined below.
• Category 1 – the analysis reported in the LR GEIS has shown the following:
–

The environmental impacts associated with the issue have been determined to apply
either to all plants or, for some issues, to plants having a specific type of cooling system
or other specified plant or site characteristics;

–

A single significance level (i.e., SMALL, MODERATE, or LARGE) has been assigned to
the impacts (except for offsite radiological impacts of spent nuclear fuel and high-level

3

Changes to the NEPA statute (42 U.S.C. § 4321 et seq.) from the Fiscal Responsibility Act of 2023
(Public Law No. 118-5, 137 Stat. 10) included adding a new Section 102(2)(F) directing agencies to
“…study, develop, and describe technically and economically feasible alternatives.” Accordingly, CEQ
defines “reasonable alternatives” as meaning a “reasonable range of alternatives that are technically and
economically feasible, and meet the purpose and need for the proposed action” (40 CFR 1508.1(hh)).

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waste disposal and offsite radiological impacts – collective impacts from other than the
disposal of spent fuel and high-level waste); and
–

Mitigation of adverse impacts associated with the issue has been considered in the
analysis, and it has been determined that additional plant-specific mitigation measures
are not likely to be sufficiently beneficial to warrant implementation.

• Category 2 – the analysis reported in the LR GEIS has shown that one or more of the criteria
of Category 1 cannot be met and therefore, additional plant-specific review is required.
If all three Category 1 criteria apply to an issue, the NRC relies on the generic finding and
analysis in this LR GEIS when conducting license renewal environmental reviews as
documented in plant-specific SEISs, provided no new and significant information is identified
requiring additional analysis. For issues that do not meet all three Category 1 criteria, the issue
is considered Category 2, and a plant-specific impact analysis is required for that issue in the
SEIS. Alternatively, an issue could remain uncategorized if the results of the NRC’s impacts
analysis remain unknown or uncertain, such as do to incomplete information.

1.6

Scope of the LR GEIS Revision

The introduction in Appendix B to Subpart A of 10 CFR Part 51 states that, on a 10-year cycle,
the Commission intends to review the material in Appendix B, including Table B-1 in the rule,
and update it, if necessary (61 FR 28467). Therefore, the NRC began the latest review in April
2020, approximately 7 years after the completion of the previous revision cycle in June 2013.
Subsequently, the NRC published a notice of intent in the Federal Register on August 4, 2020
(85 FR 47252), that notified the public of the NRC’s intent to review and potentially update
Table B-1 and the 2013 LR GEIS; indicated the results of the NRC staff’s preliminary review,
including consideration of SLR; and invited public comments and proposals for other areas that
should be updated.
At the conclusion of the scoping period, the staff began drafting a rulemaking plan. In July 2021,
the NRC staff submitted SECY-21-0066, “Rulemaking Plan for Renewing Nuclear Power Plant
Operating Licenses – Environmental Review (RIN 3150-AK32; NRC-2018-0296)” (NRC 2021l),
to request Commission approval to initiate a rulemaking to amend Table B-1 and update the
LR GEIS and associated guidance. The rulemaking plan also proposed to remove the word
“initial” from 10 CFR 51.53(c)(3), which details when license renewal applicants may rely on the
LR GEIS’s findings for Category 1 issues in preparing environmental reports in support of those
applications. These changes would have enabled SLR applicants to also rely on the LR GEIS
for Category 1 issues. The rulemaking plan would also have made corresponding changes to
the LR GEIS and the associated guidance, to indicate their applicability to SLRs.
In February 2022, the Commission issued Staff Requirements Memorandum
(SRM)-SECY-21-0066, “Rulemaking Plan for Renewing Nuclear Power Plant Operating
Licenses – Environmental Review (RIN 3150-AK32; NRC-2018-0296)” (NRC 2022c),
disapproving the staff’s recommendation and directing the staff to develop a rulemaking plan
that aligned with the Commission’s adjudicatory orders in CLI-22-03, CLI-22-02, and CLI-22-04,
which concluded that the 2013 LR GEIS did not apply to SLR applications. The SRM also
directed the NRC staff to include in the rulemaking plan a proposal to remove the word “initial”
from 10 CFR 51.53(c)(3) and to revise the LR GEIS, Table B-1, and associated guidance, to
fully account for one term of SLR.

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The NRC staff submitted SECY-22-0024, “Rulemaking Plan for Renewing Nuclear Power Plant
Operating Licenses – Environmental Review (RIN 3150-AK32; NRC-2018-0296)” (NRC 2022b),
in March 2022 requesting Commission approval to initiate a rulemaking that would align with the
Commission’s orders CLI-22-02, CLI-22-03, and CLI-22-04 regarding the NEPA analysis of SLR
applications by removing the word “initial” from 10 CFR 51.53(c)(3) and revising the LR GEIS,
Table B-1, and associated guidance to fully account for one term of SLR. In April 2022, the
Commission issued SRM-SECY-22-0024, “Rulemaking Plan for Renewing Nuclear Power Plant
Operating Licenses – Environmental Review (RIN 3150-AK32; NRC-2018-0296)” (NRC 2022d),
approving the staff’s recommendation to proceed with the rulemaking.
In April 2022, pursuant to SRM-SECY-21-0066, the staff also submitted a second paper to the
Commission, SECY-22-0036, which concluded that no further updates to the LR GEIS were
needed beyond those identified in SECY-22-0024 and that the rulemaking effort identified in
SECY-22-0024 should constitute the agency’s 10-year update to the LR GEIS. In June 2022,
the Commission approved these recommendations in SRM-SECY-22-0036.
To support this review, the NRC staff reviewed and evaluated the environmental issues and
impact findings in the 2013 LR GEIS for both initial LR and SLR. Lessons learned and
knowledge gained during previous license renewal environmental reviews provided an important
source of new information for this review. Public comments received during license renewal
environmental reviews were reexamined to validate existing environmental issues and identify
new ones. Since 2013, 15 commercial nuclear power plants have undergone an initial LR
environmental review. For the purposes of this review, the NRC also considered five SLR
environmental reviews including two reviews (i.e., North Anna and Point Beach) where the NRC
has issued a draft SEIS, but not a final SEIS. The purpose of the review for this LR GEIS was to
determine if the findings presented in the 2013 LR GEIS support the scope of license renewal
including initial LR and SLR. In doing so, the NRC considered the need to modify, add to, group,
subdivide, or delete any of the 78 environmental issues evaluated in the 2013 LR GEIS. In
summary, new research, findings, public comments, changes in applicable laws and
regulations, and other information were considered in evaluating the environmental impacts
associated with license renewal. As a result of this review, the NRC forwarded 80 environmental
issues for detailed consideration in this LR GEIS.
The staff delivered the proposed rule package SECY-22-0109, “Proposed Rule - Renewing
Nuclear Power Plant Operating Licenses - Environmental Review (RIN 3150-AK32;
NRC-2018-0296)” (NRC 2022e), and draft revised LR GEIS to the Commission for its review on
December 6, 2022. On January 23, 2023 (SRM-SECY-22-0109) (NRC 2023d), the Commission
approved publication of the proposed rule that would amend 10 CFR Part 51 in the Federal
Register for a 60-day comment period. The Commission directed the staff to modify the
proposed rule and draft LR GEIS to explicitly state that the scope of the LR GEIS encompasses
the initial license renewal and one term of SLR. The Commission also directed the staff to
include in the Federal Register notice, a specific question asking whether the proposed rule
should be expanded beyond two license renewal terms.
On March 3, 2023 (88 FR 13329), the NRC published the proposed rule, “Renewing Nuclear
Power Plant Operating Licenses–Environmental Review,” for public comment in the Federal
Register. The proposed rule would amend Table B-1, by updating the Commission’s 2013
findings on the scope and magnitude of environmental effects (impacts) of renewing the
operating license for a nuclear power plant, and other NRC environmental protection regulations
(e.g., 10 CFR 51.53, which sets forth the contents of the applicant’s environmental report). In
the proposed rule, the NRC requested public input on whether the scope of the rule should be

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expanded beyond two license renewal terms. Along with the proposed rule, the NRC requested
comment on the draft revised LR GEIS and associated draft guidance. Those comments and
the NRC’s response are discussed in Section 1.10.

1.7

Decisions to Be Supported by the LR GEIS

The decisions to be supported by the LR GEIS are whether or not to renew the operating
licenses of individual commercial nuclear power plants for an additional 20 years. The LR GEIS
was developed to support these decisions and to serve as a basis from which future NEPA
analyses for the license renewal of individual nuclear power plants would tier. In summary,
under CEQ regulations (40 CFR 1501.11(b)), tiering is the process where any agency prepares
a subsequent environmental analysis (statement or assessment) “on an action included within
the program or policy (such as a project- or site-specific action)…discussed in the broader
document,” where the broader document is a programmatic environmental document,
environmental impact statement, or environmental assessment prepared at an earlier phase or
stage. The agency’s tiered document must, in part, “…discuss the relationship between the
tiered document and the previous review, and summarize and incorporate by reference the
issues discussed in the broader document.” The tiered document must also concentrate on
“issues specific to the subsequent action, analyzing site-, phase-, or stage-specific conditions
and reasonably foreseeable effects.” CEQ also states that, “Tiering in such cases is appropriate
when it helps the agency to focus on the issues that are ripe for decision and exclude from
consideration issues already decided or not yet ripe” (40 CFR 1501.11(b)(2)(ii)). The LR GEIS
provides the NRC decisionmaker with important environmental information considered common
to all or a specific subset of nuclear power plants and allows greater focus to be placed on
plant-specific (i.e., Category 2) issues.
The scope of the environmental review for license renewal consists of the range of actions,
alternatives, and impacts to be considered in an EIS. The purpose of scoping is to identify
significant issues related to the proposed action. Scoping also identifies and eliminates from
detailed study issues that are not significant or have been covered by a prior environmental
review. Having a defined scope for the environmental review allows the NRC to concentrate on
the essential issues resulting from the actions being considered rather than on issues that may
have been or are being evaluated in different regulatory review processes, such as the license
renewal safety review (NRC 2006a).
Environmental Impact Statements
10 CFR 51.70(b): The draft environmental impact statement  will state how alternatives
considered in it and decisions based on it will or will not achieve the requirements of
Sections 101 and 102(1) of NEPA (see also the CEQ regulations, “Implementation”
(40 CFR 1502.2(d)).
The NEPA process for license renewal under 10 CFR Part 51 focuses on environmental
impacts rather than on issues related to safety. Under 10 CFR Part 54, the staff safety review
considers nuclear power plant aging management of systems, structures, and components.
Safety issues that are raised during the environmental review are forwarded to the appropriate
NRC organization for consideration and appropriate action (NRC 2006a).
The Commission determined that the NRC’s regular ongoing oversight activities are sufficient to
ensure the safety of active components during the period of extended operation, therefore the

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Commission determined that license renewal reviews only consider aging for passive, long-lived
components. Actions subject to NRC approval for license renewal are limited to the
performance of specific activities and programs necessary to manage the effects of aging on the
passive, long-lived structures and components identified in accordance with 10 CFR Part 54.
Accordingly, the LR GEIS does not serve as the NEPA review for other activities or programs
outside of license renewal.
For other actions, separate NEPA reviews must be conducted regardless of whether the action
is necessary as a consequence of receiving a renewed license, even if the activity was
specifically addressed in the LR GEIS. For example, the environmental impacts of spent fuel
pool expansion are addressed in the LR GEIS in the context of the environmental
consequences of approving a renewed operating license. However, any plant-specific
application submitted to the NRC to expand spent fuel pool capacity at a given facility would still
require its own separate NEPA review. These separate NEPA reviews may reference and
otherwise use applicable environmental information contained in the LR GEIS. For example, an
environmental assessment prepared for a separate spent fuel pool expansion request may use
the information in the LR GEIS to support a finding of no significant impact (see June 5, 1996
final rule [61 FR 28467]).
There are many factors that the NRC takes into consideration when deciding whether to renew
the operating license of a nuclear power plant. The analyses of environmental impacts
evaluated in this LR GEIS will provide the NRC’s decisionmaker with important environmental
information for use in the overall decisionmaking process. There are also decisions outside the
regulatory scope of license renewal that cannot be made based on the final LR GEIS analysis.
These decisions include the issues addressed in the following sections.
1.7.1

Changes to Nuclear Power Plant Cooling Systems

The NRC will not make a decision or any recommendations based on information presented in
this LR GEIS regarding changes to nuclear power plant cooling systems, other than those
involving safety-related issues, to mitigate adverse impacts under the jurisdiction of State or
other Federal agencies. Implementation of the provisions of the Clean Water Act (CWA;
33 U.S.C. § 1251 et seq.), including those regarding cooling system operations and design
specifications, is the responsibility of the U.S. Environmental Protection Agency (EPA). In many
cases, the EPA delegates such authority to the individual States. To operate a nuclear power
plant, licensees must comply with the CWA, including associated requirements imposed by the
EPA or the State, as part of the National Pollutant Discharge Elimination System (NPDES)
permitting system under CWA Section 402 and State water quality certification requirements
under CWA Section 401. The EPA or the State, not the NRC, sets the limits for effluents and
operational parameters in plant-specific NPDES permits. Nuclear power plants cannot operate
without a valid4 NPDES permit and must obtain a Section 401 Water Quality Certification prior to
license renewal.
1.7.2

Disposition of Spent Nuclear Fuel

The NRC will not make a decision or any recommendations based on the information presented
in this LR GEIS regarding the disposition of spent nuclear fuel at nuclear power plant sites. The
4

A valid NPDES permit is considered to be one that is either current (i.e., within its current effective date)
or one that has expired but has been “administratively continued” by the permitting authority upon the
timely submission of an application for renewal pursuant to the provisions of 40 CFR 122.6.

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scope of this LR GEIS with regard to the management and ultimate disposition of spent nuclear
fuel for the timeframe after the period of extended operation is limited to the findings codified at
10 CFR 51.23 of the September 19, 2014 Continued Storage of Spent Nuclear Fuel, Final Rule
(79 FR 56238) and associated NUREG-2157, Generic Environmental Impact Statement for
Continued Storage of Spent Nuclear Fuel (Continued Storage GEIS; NRC 2014c;
79 FR 56263).
In 1982, the Congress enacted the Nuclear Waste Policy Act (42 U.S.C. § 10101 et seq.), and
on January 7, 1983, the President signed it into law. The Nuclear Waste Policy Act defined the
Federal Government’s responsibility to provide permanent disposal in a deep geologic
repository for spent fuel and high-level radioactive waste from commercial and defense
activities. Under amended provisions (1987) of this Act, the U.S. Department of Energy has the
responsibility to locate, build, and operate a repository for such wastes. The NRC has the
responsibility to establish regulations governing the construction, operation, and closure of the
repository, consistent with environmental standards established by the EPA (see
Section 4.11.1.3 of this LR GEIS for background and status on the establishment of a geologic
repository).
Pending permanent disposal, spent nuclear fuel from nuclear power plants continues to be
stored at reactor sites (see Section 3.11.1.2 of this LR GEIS). Historically, the NRC’s Waste
Confidence Decision and Rule represented the Commission’s determination that spent fuel
could continue to be stored safely and without significant environmental impacts at reactor sites
for a period of time after the end of the licensed life for operation. The Commission incorporated
the generic determinations in a previous version of 10 CFR 51.23, which satisfied the NRC’s
obligations under NEPA for specific licensing actions that would foreseeably generate spent fuel
and high-level waste. Because the Waste Confidence Rule was originally developed in 1984,
the NRC updated the Rule periodically; the last update being completed in 2010.
On December 23, 2010, the Commission published in the Federal Register a revision of the
Waste Confidence Decision and Rule to reflect information gained from experience in the
storage of spent nuclear fuel and the increased uncertainty in the siting and construction of a
permanent geologic repository for the disposal of spent nuclear fuel and high-level waste
(75 FR 81032 and 75 FR 81037). In response to the 2010 Waste Confidence Decision and
Rule, the States of New York, New Jersey, Connecticut, and Vermont, along with several other
parties challenged the Commission’s NEPA analysis in the decision, which provided the
regulatory basis for the rule. On June 8, 2012, the U.S. Court of Appeals, District of Columbia
Circuit, in New York v. NRC, 681 F.3d 471 (New York v. NRC 2012), vacated the NRC’s Waste
Confidence Decision and Rule, after finding that it did not comply with NEPA.
In response to the court’s ruling, the Commission issued CLI-12-16 (NRC 2012e) on August 7,
2012, in which the Commission determined that it would not issue licenses that rely upon the
Waste Confidence Decision and Rule until the issues identified in the court’s decision are
appropriately addressed by the Commission. In SRM-COMSECY-12-0016 (dated September 6,
2012 [NRC 2012g]), the Commission directed the NRC staff to proceed with a rulemaking that
included the development of a generic EIS to support a revised Waste Confidence Decision and
Rule and to publish both the EIS and the revised decision and rule in the Federal Register within
24 months (by September 6, 2014).
Two LR GEIS issues in Table B-1 were affected by the court’s decision. These issues which
relied, wholly or in part, on the Waste Confidence Decision and Rule, were the “Onsite storage
of spent nuclear fuel” and “Offsite radiological impacts of spent nuclear fuel and high-level waste

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disposal.” Both of these issues were classified as Category 1 in the 1996 rule; the 2009
proposed rule continued the Category 1 classification for both of these issues. As part of its
response to the New York v. NRC decision, the NRC revised these two issues accordingly in
the 2013 LR GEIS and in the June 2013 Revisions to Environmental Review for Renewal of
Nuclear Power Plant Operating License, Final Rule (78 FR 37282). Specifically, the NRC
revised the Category 1 “Onsite storage of spent nuclear fuel” issue to limit the period of time
covered by the issue to only the license renewal term with an impact level of SMALL. Similarly,
the NRC revised the Category 1 issue, “Offsite radiological impacts of spent nuclear fuel and
high-level waste disposal” by reclassifying the issue from Category 1 having an impact level of
SMALL to uncategorized having an impact level of uncertain.
The Commission’s direction in SRM-COMSECY-12-0016 led to the 2014 Continued Storage
Final Rule (79 FR 56238), which replaced the Waste Confidence Decision and Rule with a new
regulation at 10 CFR 51.23 that codified the discussion of environmental impacts in
NUREG-2157. In addition, the 2014 Continued Storage Final Rule made conforming changes to
the two environmental issues in Table B-1 that were affected by the vacated 2010 Waste
Confidence Rule: “Onsite storage of spent nuclear fuel” and “Offsite radiological impacts of
spent nuclear fuel and high-level waste disposal.” The Commission revised the Table B-1
finding for “Onsite storage of spent nuclear fuel” to add the phrase “during the license renewal
term” to make clear that the SMALL impact is for the license renewal term only. In addition, a
new paragraph was added for this issue in Table B-1 to address the impacts of onsite storage of
spent fuel during the continued storage period. The second paragraph of the column entry was
revised to read, “For the period after the licensed life for reactor operations, the impacts of
onsite storage of spent nuclear fuel during the continued storage period are discussed in
NUREG-2157 and as stated in § 51.23(b), shall be deemed incorporated into this issue.” As
defined in the Continued Storage Final Rule, the phrase “licensed life for reactor operations”
refers to the term of the license to operate a reactor and assumes an original licensed life of
40 years and up to two 20-year license extensions for each reactor. The changes reflect that the
Category 1 findings for the issue of “onsite storage of spent nuclear fuel” cover the
environmental impacts associated with the storage of spent nuclear fuel during the license
renewal term as well as the period after the licensed life for reactor operations.
For the issue “Offsite radiological impacts of spent nuclear fuel and high-level waste disposal,”
the Continued Storage Final Rule revised the finding to reclassify the impact determination as a
Category 1 issue with no impact level assigned. The finding column entry for this issue was also
revised to reference EPA’s radiation protection standards for the high-level waste and spent
nuclear fuel disposal components of the fuel cycle. As stated in the Continued Storage Final
Rule (79 FR 56238), while the status of a geologic repository including a repository at Yucca
Mountain, remains uncertain, the NRC believes that the current radiation standards for Yucca
Mountain are protective of public health and safety and the environment. Further, the Continued
Storage GEIS (NRC 2014c) concludes that deep geologic disposal remains technically feasible.
Lessons learned and knowledge gained from operating experience and license renewal
environmental reviews completed since development of the 2013 LR GEIS regarding these
issues are discussed in Section 4.11.1 of this LR GEIS.
1.7.3

Emergency Preparedness

The NRC will not make a decision or any recommendations based on information presented in
this LR GEIS regarding emergency preparedness at nuclear power plants. Nuclear power plant
owners, government agencies, and State and local officials work together to create a system for

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emergency preparedness and response that will serve the public in the unlikely event of an
emergency. The emergency plans for nuclear power plants cover preparations for evacuation,
sheltering, and other actions to protect residents near plants in the event of a serious incident.
In the United States, 92 commercial nuclear power reactors are licensed to operate at 54 sites
in 28 States.5 Each site has onsite and offsite emergency plans to assure that adequate
protective measures can be taken to protect the public in the event of a radiological emergency.
Federal oversight of emergency preparedness for licensed nuclear power plants is shared by
the NRC and Federal Emergency Management Agency (FEMA). The NRC and FEMA have a
Memorandum of Understanding (44 CFR Part 353 Appendix A), under which FEMA has the
lead in overseeing offsite planning and response, and the NRC assists FEMA in carrying out
this role. The NRC has statutory responsibility for the radiological health and safety of the public
and retains the lead for oversight of onsite preparedness.
Before a nuclear power plant is licensed to operate, the NRC must have reasonable assurance
that adequate protective measures can and will be taken in the event of a radiological
emergency. The NRC’s decision of reasonable assurance is based on licensees complying with
NRC regulations and guidance. In addition, licensees and area response organizations must
demonstrate that they can effectively implement emergency plans and procedures during
periodic evaluated exercises. As part of the reactor oversight process, the NRC reviews
licensees’ emergency planning procedures and training. These reviews include regular drills
and exercises that assist licensees in identifying areas for improvement, such as the interface of
security operations and emergency preparedness. Each nuclear power plant owner is required
to exercise its emergency plan with the NRC, FEMA, and offsite authorities at least once every
2 years to ensure that State and local officials remain proficient in implementing their
emergency plans. Licensees also self-test their emergency plans regularly by conducting drills.
FEMA findings and determinations about the adequacy and capability of implementing offsite
plans are communicated to the NRC. The NRC reviews the FEMA findings and determinations
as well as the onsite findings. The NRC then makes a determination about the overall state of
emergency preparedness. The NRC uses the overall findings and determinations to make
radiological health and safety decisions before issuing licenses and in its continuing oversight of
operating reactors. The NRC has the authority to take action, including shutting down any
reactor deemed not to provide reasonable assurance of the protection of public health and
safety.
The Commission considered the need for a review of emergency planning issues in the context
of license renewal during its rulemaking proceedings on 10 CFR Part 54, which included
public notice and comment. As discussed in the statement of consideration for rulemaking
(56 FR 64966), the programs for emergency preparedness at nuclear power facilities apply to
all nuclear power facility licensees and require the specified levels of protection from each
licensee regardless of nuclear power plant design, construction, or license date. Requirements
related to emergency planning are in the regulations at 10 CFR 50.47 and Appendix E to
10 CFR Part 50. These requirements apply to all operating licenses and will continue to apply
to facilities with renewed licenses. Through its standards and required exercises, the

5

This count does not include Vogtle Units 3 and 4, in Waynesboro, Georgia, which commenced
commercial operations in July 2023 and April 2024, respectively. The scope of this revised LR GEIS is
limited to nuclear power plants for which an operating license, construction permit, or combined license
was issued as of June 30, 1995.

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Commission reviews existing emergency preparedness plans throughout the life of any facility,
keeping up with changing demographics and other site-related factors.
Therefore, the Commission has determined that there is no need for a special review of
emergency planning issues in the context of an environmental review for license renewal
(NRC 2006a). Thus, decisions and recommendations concerning emergency preparedness at
nuclear power plants are ongoing and outside the regulatory scope of this LR GEIS.
1.7.4

Safeguards and Security

The NRC requires that nuclear power plants be both safe and secure. Safety refers to operating
the nuclear power plant in a manner that protects the public and the environment. Security
refers to protecting the nuclear power plant (using people, equipment, and fortifications) from
intruders who wish to damage or destroy it in order to harm people and the environment.
Security issues such as safeguards planning are not tied to a license renewal action but are
issues that need to be dealt with continuously as a part of a nuclear power plant’s current (and
renewed) operating license. Security issues are periodically reviewed and updated at every
operating nuclear power plant. These reviews continue throughout the period of an operating
license, whether it is the original or renewed license. If issues related to security are discovered
at a nuclear power plant, they are addressed immediately, and any necessary changes are
reviewed and incorporated under the operating license (NRC 2006a). As such, decisions and
recommendations concerning safeguards and security at nuclear power plants are ongoing and
outside the regulatory scope of this LR GEIS.
1.7.5

Need for Power

The NRC will not make a decision or any recommendations based on information presented in
this LR GEIS regarding the need for power provided by nuclear power plants. The regulatory
authority over licensee economics (including the need for power) falls within the jurisdiction of
the States and, to some extent, within the jurisdiction of the Federal Energy Regulatory
Commission. The proposed rule for license renewal published on September 17, 1991
(56 FR 47016), had originally included a cost-benefit analysis and consideration of licensee
economics as part of the NEPA review. However, during the comment period, State, Federal,
and licensee representatives expressed concern about the use of economic costs and
cost-benefit balancing in the proposed rule and the 1996 LR GEIS. They noted that CEQ
regulations interpret NEPA as requiring only an assessment of the cumulative effects of a
proposed Federal action on the natural and human-made environment and that the
determination of the need for generating capacity has always been a State responsibility. For
this reason, the purpose and need for license renewal was defined by the Commission in the
June 5, 1996 final rule as follows (61 FR 28467):
The purpose and need for the proposed action (renewal of an operating license) is to
provide an option that allows for power generation capability beyond the term of a
current nuclear power plant operating license to meet future system generating needs,
as such needs may be determined by State, utility, and, where authorized, Federal
(other than NRC) decisionmakers.

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10 CFR 51.95(c)(2) states, in part:
The supplemental environmental impact statement for license renewal is not required to
include discussion of need for power or the economic costs and economic benefits of the
proposed action or of alternatives to the proposed action except insofar as such benefits
and costs are either essential for a determination regarding the inclusion of an
alternative in the range of alternatives considered or relevant to mitigation.
1.7.6

Seismicity, Flooding, and Other Natural Hazards

The NRC will not make a decision or any recommendations based on information presented in
this LR GEIS regarding seismic risk and flooding at nuclear power plants. The NRC’s
assessment of seismic and flood hazards for existing nuclear power plants is a separate and
distinct process from license renewal reviews. Seismic and flood hazard issues are
appropriately addressed by the NRC on an ongoing basis at all licensed nuclear facilities as part
of its regulatory oversight activities. As such, decisions and recommendations concerning
seismic risk and flooding at nuclear power plants are outside the regulatory scope of this
LR GEIS. Following the accident at the Fukushima Dai-ichi nuclear power plant resulting from
the March 11, 2011, Great Tohoku Earthquake and subsequent tsunami, the NRC established
the Near-Term Task Force as directed by the Commission on March 23, 2011, in
COMGBJ-11-0002 (NRC 2011e). In consideration of the lessons learned following the
Fukushima Dai-ichi accident, the NRC staff developed an enhanced process to make sure that
there is an ongoing assessment of information on a range of natural hazards that could
potentially pose a threat to nuclear power plants. The framework developed as part of this
process provides a graded approach that allows the NRC to proactively, routinely, and
systematically seek, evaluate, and respond to new hazard information (NRC 2016f). In 2017,
the Commission approved the staff’s process enhancements for an ongoing assessment of
natural hazard information (NRC 2017).

1.8
1.8.1

Implementation of the Rule (10 CFR Part 51)
General Requirements

The regulatory requirements for conducting a NEPA review for license renewal are similar to the
NEPA review requirements for other major nuclear plant licensing actions. Consistent with the
current NEPA practice for nuclear plant licensing actions, an applicant is required to submit an
environmental report that assesses the environmental impacts associated with the proposed
action, considers alternatives to the proposed action, and evaluates any alternatives for
reducing adverse environmental effects. For license renewal, the NRC prepares a draft SEIS to
the LR GEIS for public comment and issues a final SEIS after considering public comments on
the draft.
1.8.2

Applicant’s Environmental Report

The applicant’s environmental report must contain an assessment of the environmental
impacts of renewing a license, the environmental impacts of alternatives, and mitigation
alternatives. In assessing the environmental impacts of license renewal for the environmental
report, the applicant should refer to the summary of findings on environmental issues for license
renewal in Table B-1 of 10 CFR Part 51. The license renewal applicant is not required to assess
the environmental impacts of Category 1 issues listed in Table B-1 unless the applicant is aware
of new and significant information that would change the conclusions in the LR GEIS. For

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Category 2 issues listed in Table B-1, the applicant must provide a plant-specific assessment of
the impacts. The NRC’s regulation in 10 CFR 51.53(c)(3)(ii) specifies the areas that must be
analyzed for the Category 2 issues in the environmental report.
The NRC’s regulations in 10 CFR 51.45(c) and 10 CFR 51.53(c)(2) require license renewal
applicants to consider alternatives for reducing or avoiding adverse environmental effects
associated with the proposed action. Typically, this consideration is limited to the Category 2
NEPA issues listed in Table B-1. Pursuant to 10 CFR 51.45(d), the environmental report must
also include a discussion of the status of compliance with applicable Federal, State, and local
environmental standards. In addition, the NRC’s regulation in 10 CFR 51.53(c)(2) specifically
excludes the consideration of need for power, the economic costs and benefits of the proposed
action, or alternatives to the proposed action in the environmental report for license renewal,
except when such consideration is essential for determining whether to include an alternative in
the range of alternatives or is relevant to mitigation. Other issues excluded from consideration in
the environmental report include issues not related to the environmental effects of the proposed
action (license renewal) and associated alternatives. The applicant should also demonstrate the
consideration of a range (set) of reasonable alternatives to license renewal in the environmental
report and is not limited to the alternatives and energy technologies presented in this LR GEIS.
Information provided in the applicant’s environmental report will be used in preparing the
NRC’s SEIS.
1.8.3

Supplemental Environmental Impact Statement

As required by 10 CFR 51.20(b)(2), the NRC is required to prepare a SEIS to the LR GEIS for
each license renewal environmental review. The SEIS serves as the NRC’s analysis of the
environmental impacts of license renewal as well as a comparison of the impacts of alternatives.
This document also presents the NRC’s recommendation about the environmental impact of
license renewal. SEISs for license renewal do not need to include a discussion of the need for
power or the economic costs and economic benefits of the proposed action or of alternatives to
the proposed action (10 CFR 51.95(c)(2)).
1.8.4

Public Scoping and Public Comments

The NRC conducts public scoping meetings to inform the public about the license renewal
process and receive comments on the scope of the NRC’s plant-specific environmental review.
At the conclusion of the scoping period, NRC reviews and considers public comments in a
scoping summary report. In addition, the draft SEIS is issued for public comment (see
10 CFR 51.73). In reviewing public scoping comments on the proposed action and comments
on the draft SEIS, the NRC determines whether each comment provides any new and
significant information compared to the information and conclusions presented in the LR GEIS
(for Category 1 issues) as well as the information it provides on Category 2 issues considered in
the SEIS. If comments are determined to provide new and significant information that could
change the conclusions in the LR GEIS, these comments will be addressed in the SEIS.
1.8.5

Draft Supplemental Environmental Impact Statement

The NRC’s draft SEIS presents an analysis of the environmental impacts of the proposed
license renewal action and the environmental impacts of the alternatives to the proposed action.
The NRC considers (1) the summary of findings on environmental issues for license renewal of
nuclear power plants in Table B-1 of 10 CFR Part 51 for Category 1 issues, (2) plant-specific
environmental impact analyses of Category 2 issues, and (3) any new and significant

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information from the applicant’s environmental report or identified through public scoping and
comment to reach a conclusion regarding the environmental impacts of license renewal. These
impacts are then compared to the environmental impacts of replacement energy alternatives.
1.8.6

Final Supplemental Environmental Impact Statement

The NRC issues a final SEIS in accordance with 10 CFR 51.91 and 51.93 after considering
(1) public comments, (2) the plant-specific environmental impact analysis of Category 2 issues,
and (3) new and significant information involving Category 1 issues summarized in Table B-1.
The NRC provides a record of its decision regarding the environmental impacts of the proposed
license renewal action (see 10 CFR 51.102 and 51.103). All comments on the draft SEIS are
addressed by the NRC in the final SEIS in accordance with 10 CFR 51.91(a)(1). Comments
regarding Category 1 issues are addressed in the following manner:
• The NRC’s response to a comment regarding the applicability of the analysis of an impact
codified in the rule (i.e., 10 CFR Part 51) to the plant in question may be a statement and
explanation of its view that the analysis is adequate including, if applicable, consideration of
the significance of any new information. A commenter dissatisfied with such a response may
file a petition for rulemaking under 10 CFR 2.802. Procedures for the submission of petitions
for rulemaking are explained in 10 CFR Part 2. If a commenter is successful in persuading the
Commission that the new information does indicate that the analysis of an impact codified in
the rule is incorrect in significant respects (either in general or with respect to the particular
plant), then a rulemaking proceeding will be initiated.
• If a commenter provides new information that is relevant to the plant and is also relevant to
other plants (i.e., generic information) and that information demonstrates that the analysis of
an impact codified in the rule is incorrect, the NRC staff will seek Commission approval either
to suspend the application of the rule on a generic basis with respect to the analysis or to
delay granting the renewal application (and possibly other renewal applications) until the rule
can be amended. This LR GEIS would reflect the corrected analysis and any additional
consideration of alternatives as appropriate.
• If a commenter provides new, plant-specific information that demonstrates that the analysis of
an impact codified in the rule is incorrect with respect to the particular plant, then the NRC
staff will seek Commission approval to waive the application of the rule with respect to that
analysis in that specific renewal proceeding. The SEIS would reflect the corrected analysis as
appropriate.
The NRC will also consider comments on Category 2 issues and make any necessary changes
to the SEIS or explain why no changes were needed.
1.8.7

Consultations

Plant-specific license renewal environmental reviews may require consultation with other
Federal, State, regional, and local agencies and Indian Tribes. For license renewal, the NRC
staff must consider the effects of its actions on ecological resources protected under Federal
statutes, including the Endangered Species Act (16 U.S.C. § 1531 et seq.), Magnuson-Stevens
Fishery Conservation and Management Act (MSA; 16 U.S.C. § 1801 et seq.), and National
Marine Sanctuaries Act (16 U.S.C. § 1431 et seq.). Section 106 of the National Historic
Preservation Act (54 U.S.C. § 300101 et seq.) requires Federal agencies to take into account
the effects of their undertakings on historic properties. For further information about these
consultations, see Sections 3.6.3 and 3.7.2 of this LR GEIS.

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Federal Trust Relationship and the NRC’s Tribal Policy Statement
The NRC shares the Federal government’s unique Trust Relationship with, and Trust
Responsibility to, Federally recognized Indian Tribes. Under the Federal Trust Doctrine, the
United States—and the individual agencies of the Federal government—owe a fiduciary duty to
Federally recognized Indian Tribes. The nature of that duty depends on the underlying
substantive laws (i.e., treaties, statutes, agreements) creating the duty (82 FR 2402). Many
Federally recognized Indian Tribes have an interest in public health and safety and
environmental protection associated with NRC regulatory activities, including license renewal of
nuclear power plants. The NRC exercises its Trust Responsibility in the context of its authorizing
statutes including the Atomic Energy Act (42 U.S.C. § 2011 et seq.), the Energy Reorganization
Act of 1974 (42 U.S.C. 5801 et seq.), the Nuclear Waste Policy Act of 1982 (42 U.S.C. § 10101
et seq.), the Low-Level Radioactive Waste Policy Act of 1985 (42 U.S.C. § 2021b et seq.), and
the Uranium Mill Tailings Radiation Control Act of 1978 (42 U.S.C. 7901 et seq.), as amended
(82 FR 2402).
Other statutory provisions such as the National Historic Preservation Act can require Tribal
consultation as part of the NRC’s evaluation of agency activities during licensing actions
(e.g., initial LR or SLR), rulemaking, or policy development. The NRC complies with statutory
provisions and NRC regulatory provisions that require Tribal consultation and interacts with
Tribal governments on a government-to-government basis accordingly (82 FR 2402).
On January 9, 2017, the NRC published its Tribal Policy Statement of principles to guide the
agency’s interactions with American Indian and Alaska Native Tribes (82 FR 2402). The policy
statement is intended to encourage and facilitate Tribal involvement in activities under NRC
jurisdiction. The policy statement also underscores the NRC’s commitments to conducting
outreach to Tribes and engaging in timely consultation, and to coordinate with other Federal
agencies. The policy statement is based on the United States Constitution, treaties, statutes,
executive orders, judicial decisions, and the unique relationship between Indian Tribes and the
Federal government (82 FR 2402).6
As an independent regulatory agency that does not hold in trust Tribal lands or assets or
provide services to Federally recognized Tribes, the NRC fulfills its Trust Responsibility through
implementation of the principles of the Tribal Policy Statement, by providing protections under
its implementing regulations, and through recognition of additional obligations consistent with
other applicable treaties and statutory authorities (82 FR 2402).

1.9

Public Scoping Comments on the LR GEIS Update

In support of the proposed review and update of the LR GEIS, the NRC staff conducted a
thorough environmental scoping process in 2020. The scoping process was conducted in
accordance with Commission direction and the NRC’s regulations in Appendix B,
“Environmental Effect of Renewing the Operating License of a Nuclear Power Plant,” to
Subpart A, “National Environmental Policy Act – Regulations Implementing Section 102(2),” of
6

This Tribal Policy Statement is not intended to, and does not, grant, expand, create, or diminish any
rights, benefits, or trust responsibilities, substantive or procedural, enforceable at law or in equity in any
cause of action by any party against the United States, the Commission, or any person. This Tribal Policy
Statement does not alter, amend, repeal, interpret, or modify Tribal sovereignty, any treaty rights of any
Indian Tribes, or preempt, modify, or limit the exercise of such rights. Nothing in this Tribal Policy
Statement shall be interpreted as amending or changing the Commission’s regulations.

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10 CFR Part 51, “Environmental Protection Regulations for Domestic Licensing and Related
Regulatory Functions”. The introduction in Appendix B to Subpart A of 10 CFR Part 51 states
that, on a 10-year cycle, the Commission intends to review the material in Appendix B, including
Table B-1, and update it, if necessary (61 FR 28467). Thus, the NRC began the latest review in
April 2020, approximately 7 years after the completion of the previous revision cycle in
June 2013.
On August 4, 2020, the NRC staff issued a Federal Register notice (85 FR 47252) initiating the
scoping process to solicit public input to support the review to determine whether to update the
LR GEIS, including updates to address SLR. It provided the public and other governmental
entities with an opportunity to comment on the review and propose areas for updating, in
accordance with 10 CFR 51.29. The NRC staff also directly contacted other Federal agencies,
States, and Tribes to invite their participation.
The scoping process consisted of a 90-day public comment period and included four webinar
meetings conducted on August 19, 2020, and August 27, 2020, from 1:30 p.m. to 4:00 p.m. and
from 6:30 p.m. to 9:00 p.m. to receive comments from the public. Because of the COVID-19
public health emergency, no in-person meetings were held. The contents of each webinar
meeting were transcribed by a court reporter. On August 19, approximately 40 people attended
the two public webinar meetings, including representatives from the nuclear industry and
Federal and State agencies. On August 27, approximately 20 people collectively attended the
two webinar meetings, including representatives from the nuclear industry and Federal and
State agencies. The official transcripts are available in NRC’s Agencywide Documents Access
and Management System (NRC 2020j). The public scoping period ended on November 2, 2020.
At the conclusion of the scoping period, the NRC staff issued Environmental Impact Statement
Scoping Process Summary Report, Review and Update of the Generic Environmental Impact
Statement for License Renewal of Nuclear Plants (NUREG-1437), dated June 2021
(NRC 2021e). The report contains (1) comments received during the public meeting, via email,
and through Regulations.gov; (2) public comments grouped by subject area; and (3) NRC staff
responses to those comments.
All scoping comments received were considered as part of the staff’s review and update and are
referenced in Volume 2, Appendix A, Section A.1 of this LR GEIS.

1.10 Public Comments on the Draft LR GEIS
The public comment process for the draft LR GEIS was similar to that used for plant-specific
SEISs and other NRC NEPA documents. In March 2023, NRC distributed the draft LR GEIS to
Federal, State, and local government agencies; Federally recognized Indian Tribes;
environmental interest groups; and members of the public who requested copies. As part of the
process to solicit public comments on the draft revised LR GEIS, the NRC:
• Established a public website to consolidate pertinent rulemaking information.
• Published the proposed rule, draft LR GEIS, and associated guidance for public comment in
the Federal Register (88 FR 13329).
• Issued press releases and social media posts regarding the issuance of the draft LR GEIS,
associated guidance, and proposed rule; announcing public meetings; and providing
instructions on how to provide comments.

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• Issued a Federal Register notice (88 FR 14958) notifying the public of six public meetings to
receive comments on the draft LR GEIS and proposed rule.
• Conducted hybrid (in-person with virtual attendance option) public meetings in (1) Rockville,
Maryland, on March 16, 2023 (two sessions); (2) Naperville, Illinois, on March 28, 2023;
(3) Westlake, Texas, on March 30, 2023; (4) King of Prussia, Pennsylvania, on April 4, 2023;
and (5) Decatur, Georgia, on April 6, 2023.
• Conducted an informational meeting with Federally recognized Tribes on April 19, 2023, to
provide an overview of the proposed rule and draft LR GEIS and afford Tribal representatives
an opportunity to discuss the rule with NRC staff.
Approximately 220 people attended the meetings, either in-person or virtually. During the
public comment period, the NRC received a total of 1,889 comment submissions consisting of
44 unique technically complex submissions, which the NRC posted to the Federal Rulemaking
website (Regulations.gov), along with comments received during the six public meetings.
During the comment period, 1,839 individuals submitted a campaign letter organized by the
Nuclear Information and Resource Service. The NRC reviewed public meeting transcripts,
comment letters, and emails, which have been referenced and incorporated by reference in this
LR GEIS (see Volume 2, Appendix A, Section A.2, Table A.2-1). The public comment
documents received are also available online in the Agencywide Documents Access and
Management System and on the Federal rulemaking website (Regulations.gov) under Docket
ID NRC_2018-0296. The NRC considered all comments received when developing the final
LR GEIS. NRC responses to all comments received are included in Volume 2, Appendix A.2, of
this LR GEIS.
The NRC received comments that resulted in changes for one issue considered in this
LR GEIS, “Microbiological hazards to the public” (Category 2). The NRC received a comment
stating that the proposed addition to Section 3.9.2.2 of the LR GEIS regarding discharges to
waters of the United States infers reference to the Clean Water Act, which has the potential to
expand the scope of this issue, if changes to the definition of “waters of the United States” occur
in the future. The comment also recommended limiting the scope of the issue to waters
receiving discharges that are accessible to the public for “recreational use.” While the NRC staff
disagrees with limiting the scope of the issue as suggested, the staff agrees that reference to
the Clean Water Act should be removed. The NRC modified the text in Section 3.9.2.2 of this
LR GEIS; Sections 3.9 and 4.9 in Regulatory Guide 4.2, Supplement 1, Revision 2; and
Sections 3.9 and 4.9 in NUREG-1555, Supplement 1, Revision 2, to reflect that members of the
public could be exposed to microbiological organisms in thermal effluents at nuclear plants that
use cooling ponds, lakes, canals, or that discharge to publicly accessible surface waters. The
NRC also updated the text in Chapter 2 (i.e., Table 2.1-1), Section 4.9.1.1.3 of this LR GEIS,
and in Section 51.53(c)(3)(ii)(G) and Table B-1 of the final rule for consistency.
Otherwise, none of the other comments received by the NRC provided any new information that
would challenge the findings for Category 1 or Category 2 issues in this revised LR GEIS.
Nevertheless, as reflected in this LR GEIS, associated guidance (Regulatory Guide 4.2,
Supplement 1, Revision 2 and NUREG-1555, Supplement 1, Revision 2), and final rule, the
NRC did make a number of clarifying changes in response to some comments.
Alleged new or emerging information of a nuclear plant-specific nature provided in comments
appropriately considered in a plant-specific supplement to the LR GEIS or similar analysis rather
than in this LR GEIS and associated rulemaking. Specifically, as part of a plant-specific

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Introduction
environmental review, the NRC staff will determine if there is any new and significant
information that was not considered in the LR GEIS for Category 1 issues. Thus, even though
an issue is designated as Category 1, mechanisms are in place to conduct a full plant-specific
review if new and significant information warrants such a review.
Changes made in response to comments in this final LR GEIS, as well as changes made to
include updated information, corrections, and substantial editorial revisions are marked with a
change bar (vertical line) on the side margin of the page where the changes or additions were
made. Minor editorial revisions and those limited to formatting are not marked.

1.11 Lessons Learned
As previously discussed, the NRC reviewed and evaluated the environmental impacts of license
renewal. In conducting a thorough update to the LR GEIS that reflects the “hard look” that is
required for a NEPA document, the NRC considered changes in applicable laws and
regulations, new data in its possession from scientific literature and nuclear power plant
operations, collective experience, and lessons learned and knowledge gained from conducting
environmental reviews for initial LR and SLR since development of the 2013 LR GEIS. The NRC
also considered comments received on the draft LR GEIS and proposed rule (see Section 1.10)
in finalizing this LR GEIS. These developments and practical insights provided an important
source of new information for this LR GEIS revision.
The purpose of this review and evaluation was to determine if the findings presented in the
2013 LR GEIS support the scope of license renewal, including for initial LR and SLR. In doing
so, the NRC considered the need to modify, add, group, subdivide, or delete any of the
78 issues in the 2013 LR GEIS. After this review and evaluation, the NRC identified
80 environmental issues (i.e., 59 Category 1, 20 Category 2, and 1 uncategorized issue) for
detailed consideration in this LR GEIS revision. The following summarizes the types of changes
to Table B-1. These changes are listed by order of appearance in Table B-1, not by order of
importance:
• One Category 2 issue, “Groundwater quality degradation (cooling ponds at inland sites),” and
a related Category 1 issue, “Groundwater quality degradation (cooling ponds in salt
marshes),” were consolidated into a single Category 2 issue, “Groundwater quality
degradation (plants with cooling ponds).”
• Two related Category 1 issues, “Infrequently reported thermal impacts (all plants),” and
“Effects of cooling water discharge on dissolved oxygen, gas supersaturation, and
eutrophication,” and the thermal effluent component of the Category 1 issue, “Losses from
predation, parasitism, and disease among organisms exposed to sublethal stresses,” were
consolidated into a single Category 1 issue, “Infrequently reported effects of thermal
effluents.”
• One Category 2 issue, “Impingement and entrainment of aquatic organisms (plants with oncethrough cooling systems or cooling ponds),” and the impingement component of a Category 1
issue, “Losses from predation, parasitism, and disease among organisms exposed to
sublethal stresses,” were consolidated into a single Category 2 issue, “Impingement mortality
and entrainment of aquatic organisms (plants with once-through cooling systems or cooling
ponds).”

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Introduction
• One Category 1 issue, “Impingement and entrainment of aquatic organisms (plants with
cooling towers),” and the impingement component of the Category 1 issue, “Losses from
predation, parasitism, and disease among organisms exposed to sublethal stresses,”
were consolidated into a single Category 1 issue, “Impingement mortality and entrainment of
aquatic organisms (plants with cooling towers).”
• One Category 2 issue, “Threatened, endangered, and protected species and essential fish
habitat,” was divided into three Category 2 issues: (1) “Endangered Species Act: federally
listed species and critical habitats under U.S. Fish and Wildlife Service jurisdiction,”
(2) “Endangered Species Act: federally listed species and critical habitats under National
Marine Fisheries Service jurisdiction,” and (3) “Magnuson-Stevens Act: essential fish habitat.”
• Two new Category 2 issues, “National Marine Sanctuaries Act: sanctuary resources” and
“Climate change impacts on environmental resources,” were added.
• One Category 2 issue, “Severe accidents,” was changed to a Category 1 issue.
• One new Category 1 issue, “Greenhouse gas impacts on climate change,” was added.
• Several issue titles and findings were revised for clarity.
Historically, the issues identified in the LR GEIS have served to accurately categorize most
environmental impacts associated with license renewal. While there have been a number of
instances where new (but not significant) information was discovered during a license renewal
environmental review for Category 1 issues since publication of the 2013 LR GEIS, the number
of instances where information was determined to be both new and significant has been limited.
Most notably, in the SEIS for second renewal of Turkey Point, the NRC found that new
information for the Category 1 (generic) issue “Groundwater quality degradation (plants with
cooling ponds in salt marshes)” was both new and significant for the initial LR term
(NRC 2019c). As noted above, that issue was consolidated with a Category 2 issue,
“Groundwater quality degradation (cooling ponds at inland sites),” into a new Category 2 issue,
“Groundwater quality degradation (plants with cooling ponds).”

1.12 Organization of the LR GEIS
Consistent with the 2013 LR GEIS, this LR GEIS revision adopts the NRC’s standard format for
EISs as established in 10 CFR Part 51, Subpart A, Appendix A.7 The following list describes the
contents of each chapter and appendix of the LR GEIS:
• Chapter 2 presents brief descriptions of the proposed action (including nuclear plant
operations, refurbishment, and termination of operations and decommissioning) during the
license renewal term and a summary of impacts, the no action alternative, and energy
alternatives.
• Chapter 3 presents a general description of the affected environment in the vicinity of
operating commercial nuclear power plants in the United States. Included are descriptions of
nuclear power plant facilities and operations followed by general descriptions of existing
7

The NRC made targeted changes, including removal of duplicative text, and organizational changes to
this LR GEIS to address changes to NEPA from the Fiscal Responsibility Act of 2023 (Public Law No.
118-5, 137 Stat. 10). The changes include the relocation of text and other materials from Chapters 2, 3,
and 4, and Chapters 6, 7, and 8 in their entirety, to the appendices to revise the document to be less than
the 300-page limit (not including appendices, citations, figures, tables, and other graphics) for
environmental impact statements analyzing proposed agency actions of “extraordinary complexity”
specified in the revised NEPA statute.

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Introduction
conditions in the following topical areas: (1) land use and visual resources; (2) meteorology,
air quality, and noise; (3) geologic environment; (4) water resources (surface water resources
and groundwater resources); (5) ecological resources (terrestrial resources, aquatic
resources, and federally protected ecological resources); (6) historic and cultural resources;
(7) socioeconomics; (8) human health (radiological and nonradiological hazards);
(9) environmental justice; (10) waste management and pollution prevention; and
(11) greenhouse gas emissions and climate change.
• Chapter 4 presents the environmental consequences associated with the proposed action
(license renewal) including the incremental effects of continued operations and refurbishment
on each of the topical areas presented in Chapter 3. The environmental consequences of the
uranium fuel cycle, terminating power plant operations, cumulative effects (impacts), and
resource commitments associated with the proposed action are also discussed in Chapter 4.
• Chapter 5 presents the references for Chapters 1 through 4.
• Appendix A presents the results of the scoping process conducted for the LR GEIS and
rulemaking followed by the comments received on the proposed rule package and the NRC’s
responses to those comments.
• Appendix B presents a comparison of the NRC’s license renewal environmental issues and
findings for the 1996, 2013, and this revised rulemaking.
• Appendix C presents brief descriptions of the commercial nuclear power plants that are the
subject of this LR GEIS and rulemaking.
• Appendix D presents a description of the alternatives to the proposed action and their
associated environmental effects (impacts).
• Appendix E provides supporting analyses for the NRC’s analysis of postulated accidents.
• Appendix F presents an overview of Federal and State laws, regulations, and other
requirements potentially applicable to the NRC’s license renewal environmental reviews.
• Appendix G presents the technical methodology for the NRC’s analysis of the affected
environment and environmental consequences of license renewal.
• Appendix H presents a list of the preparers for this LR GEIS.
• Appendix I provides a list of agencies, organizations, and persons to whom this LR GEIS
was distributed.
• Appendix J provides a glossary of common terms used in this LR GEIS.

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ALTERNATIVES INCLUDING THE PROPOSED ACTION

The proposed action is the renewal of a commercial nuclear power plant’s operating license. The
U.S. Nuclear Regulatory Commission’s (NRC’s) regulations in Title 10 of the Code of Federal
Regulations (10 CFR) Part 51, implementing Section 102(2) of the National Environmental Policy
Act (NEPA; 42 U.S.C. § 4321 et seq.), requires the consideration of alternatives to renewing the
nuclear power plant’s operating license and the comparison of the environmental effects
(impacts) of renewing the operating license to the environmental impacts of reasonable
alternatives (40 CFR 1502.14). This allows the NRC to determine whether the environmental
impacts of license renewal are so great that preserving the option of license renewal for
energy-planning decisionmakers would be unreasonable. If the NRC decides not to renew the
operating license of a nuclear power plant, energy-planning decisionmakers will then have to find
alternative means of addressing energy needs. Alternatives to license renewal include other
means of generating electricity, as well as offsetting demand using conservation and energy
efficiency measures (demand-side management), delaying planned retirements of other existing
plants, or purchasing sufficient power to replace the capacity supplied by the existing nuclear
power plant.
Contents of Chapter 2
• Proposed Action (Section 2.1)
• No Action Alternative (Section 2.2)
• Alternative Energy Sources (Section 2.3)
• Comparison of Alternatives (Section 2.4)
If the NRC renews the operating license, the decision about whether to continue nuclear power
plant operations will be made by the licensee and State or other Federal (non-NRC)
decisionmakers. This decision may be based on economic, reliability, operational, policy, and
environmental objectives.
Section 2.1 below in this revision of NUREG-1437, Generic Environmental Impact Statement for
License Renewal of Nuclear Plants (LR GEIS) describes the proposed action, including nuclear
plant operations during the license renewal term (initial license renewal (initial LR) or
subsequent license renewal (SLR)), refurbishment, and other activities associated with license
renewal. Most of these activities would be the same as or similar to those already occurring at
the nuclear plant. Termination of nuclear plant operations would occur at or before the end of
the license renewal term, and decommissioning activities would commence after reactor
operations have ceased.
The impacts of the proposed action and any refurbishment activities that may be undertaken in
support of license renewal are presented in Chapter 4 and summarized in Section 2.1.4,
including each of the identified 80 environmental issues, their significance (SMALL,
MODERATE, or LARGE, as defined in Section 1.5), and whether the impact designation would
apply to all or a specific subset of nuclear plants. Section 2.2 describes the no action alternative
(not renewing the operating license), and Section 2.3 presents alternatives for replacing existing
nuclear generating capacity using other energy sources, including fossil fuel, new nuclear,
renewable energy, and offsetting existing nuclear generating capacity, including demand-side

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Alternatives Including the Proposed Action
management, delayed retirement, and purchased power. Appendix D describes these
alternatives in detail and presents NRC’s evaluation of their potential environmental
consequences (impacts).
The NRC does not reach a generic conclusion regarding the impacts of alternatives to license
renewal and will consider these impacts in nuclear power plant-specific (hereafter called
plant-specific) supplemental environmental impact statements (SEISs). However, Section 2.4
presents a summary comparison of the impacts of the proposed action to these alternatives.
Alternatives to the Proposed Action Considered in the LR GEIS
• Not renewing the operating licenses of commercial nuclear power plants (no action
alternative).
• Replacing existing nuclear generating capacity using other energy sources (including fossil
fuel, new nuclear, and renewable energy).
• Offsetting existing nuclear generation capacity using conservation and energy efficiency
(demand-side management), delayed retirement, or purchased power.

2.1

Proposed Action

As stated in Section 1.2, the proposed action is the renewal of commercial nuclear power plant
operating licenses. For the NRC to determine whether the license should be renewed, an
applicant is required to perform certain safety analyses to demonstrate that the nuclear power
plant and the licensee can effectively manage the effects of aging and continue safe reactor
operations during the renewal term. These safety analyses include an assessment of the effects
of potential age-related degradation of certain long-lived, passive systems, structures, and
components (SSCs). This requires applicants to describe the conditions under which the plant
would operate during the license renewal term. A description of nuclear plant operations during
the license renewal term is provided in Section 2.1.1.
Applicants may also conduct refurbishment activities (replacement of major components and
systems) necessary to continue reactor operation during the renewal term. These are described
in Section 2.1.2. Section 2.1.3 presents an overview of the termination of nuclear plant
operations and decommissioning process. Termination of operations and decommissioning
impacts are addressed in Chapter 4, Section 4.14.2.
2.1.1

Nuclear Plant Operations during the License Renewal Term

This section describes nuclear plant operations, maintenance, and refueling activities, including
aging management reviews, required for license renewal. During the license renewal term,
nuclear plants would continue to operate in the same manner as they do now. All nuclear
reactors currently operating in the United States are light water reactors, of which there are two
basic types—pressurized water reactors and boiling water reactors. A brief description of these
reactors and baseline conditions during their operation are presented in Chapter 3.
Activities conducted at nuclear plants include:
• reactor operations;
• waste management (processing, storage, packaging, and offsite shipment of wastes);

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Alternatives Including the Proposed Action
• security (includes site security personnel);
• office and clerical work (management, public relations, and support staff);
• laboratory analysis;
• surveillance, monitoring, and maintenance (e.g., equipment testing and inspections); and
• refueling and other outages (additional workers during outage).
These activities are expected to continue during the license renewal term. Certain SSCs such
as the reactor pressure vessel, reactor containment building, and piping would continue to
operate into the license renewal term. The regulations in 10 CFR Part 54 place certain
requirements on licensees to make sure that such SSCs continue to operate safely. Incremental
aging management activities implemented to allow operation of a nuclear power plant beyond
the current license term are assumed to fall under one of two broad categories: (1) surveillance,
monitoring, inspection, testing, trending, and recordkeeping actions, most of which are repeated
at regular intervals, and (2) major refurbishment actions, which usually occur infrequently and
possibly only once in the life of the plant for any given item. Refurbishment activities are
discussed in Section 2.1.2.
The NRC finds that the approaches to environmental impacts from refurbishment activities
contained in the previous LR GEISs are valid and conservative. The approaches yield
environmental impacts that are likely greater than—or at least equal to—the actual impacts
during the license renewal term.
2.1.2

Refurbishment and Other Activities Associated with License Renewal

The NRC assumes that licensees may need to conduct refurbishment activities to ensure the
safe and economic operation of nuclear plants during the license renewal term. Refurbishment
activities include replacement and repair of SSCs. Replacement activities include replacing
steam generators and pressurizers for pressurized water reactors and recirculation piping
systems for boiling water reactors. It is assumed that some applicants may undertake
construction projects to replace or improve power plant infrastructure. Such projects could
include construction of new parking lots, roads, storage facilities, office buildings, structures,
and other facilities.
The number of SSCs involved in refurbishment and the frequency and duration of each activity
would vary. In many circumstances, refurbishment activities (e.g., steam generator and reactor
vessel head replacement) have already taken place at a number of nuclear plants. These
refurbishment-type activities were conducted for economic, reliability, or efficiency reasons
during refueling or maintenance outages (i.e., not for license renewal). In addition, very few
applications have identified any refurbishment activities associated with license renewal.
Impacts from refurbishment activities outside of license renewal are assumed to have been
considered in annual site evaluation reports, environmental operating reports, and Radiological
Environmental Monitoring Program reports. Detailed analyses of environmental impacts have
not been performed for refurbishment actions in this LR GEIS revision because these actions
would vary at each nuclear plant. Refurbishment activities proposed by license renewal
applicants in their environmental report will be addressed in plant-specific environmental
reviews. Chapter 4 of this LR GEIS considers the impacts of representative or bounding
refurbishment activities in a number of resource areas.

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2.1.3

Termination of Nuclear Plant Operations and Decommissioning after License
Renewal

Environmental impacts caused by the licensee’s decision to permanently cease nuclear plant
operations and enter into decommissioning are outside the scope of the LR GEIS. This includes
impacts following the termination of reactor operations and the removal of fuel from the reactor
vessel, regardless of when or why the decision is made. The environmental impacts from
decommissioning are addressed in NUREG-0586, Generic Environmental Impact Statement on
Decommissioning of Nuclear Facilities, Supplement 1: Regarding the Decommissioning of
Nuclear Power Reactors (Decommissioning GEIS) (NRC 2002c).
Most nuclear plant activities and systems dedicated to reactor operations would cease after
reactor shutdown. Some activities (e.g., security and spent nuclear fuel management) would
continue, while other activities (administration, laboratory analysis, and reactor surveillance,
monitoring, and maintenance) may be reduced or eliminated. Shared systems at a nuclear
power plant that have multiple units would continue to operate but at reduced capacity until all
units cease operation. The cessation of activities needed to maintain and operate the reactor
would reduce the need for workers at the nuclear power plant, but it would not lead to the
immediate dismantlement of the reactor or its infrastructure.
As further discussed in Section 4.14.2 of this LR GEIS, the decommissioning process begins
when the licensee informs the NRC that it has permanently ceased reactor operations,
defueled, and intends to decommission the nuclear plant. Regulations in 10 CFR 50.82(a)(4)(i)
require operating reactor licensees to submit a post-shutdown decommissioning activities report
to the NRC, and forward a copy to the affected State(s), no later than 2 years after the cessation
of reactor operations.
2.1.4

Impacts of the Proposed Action

When evaluating the impacts of the proposed action, 80 environmental issues were identified:
72 issues associated with continued operations and any refurbishment during the initial LR and
SLR terms; 2 with postulated accidents; 1 with the termination of nuclear power plant operations
and decommissioning; 4 with the uranium fuel cycle; and 1 with cumulative effects. These
include 59 Category 1, 20 Category 2, and 1 uncategorized issue. For all issues, the focus of
the evaluation was on the incremental effects (impacts) of license renewal (for the initial LR or
SLR term) relative to the no action alternative. Impact significance levels and categories are
defined in Section 1.5.
A summary of the environmental impacts of the proposed action is presented in Table 2.1-1.
The technical basis for the impact determinations presented in this table is found in Chapter 4 of
this LR GEIS in Sections 4.2 through 4.14.

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Table 2.1-1 Summary of Findings on Environmental Issues under the Proposed Action
(Initial and One Term of Subsequent License Renewal)
Impact Finding(a)(b)

Environmental Issue
Land Use
Onsite land use

SMALL (Category 1). Changes in onsite land use from continued
operations and refurbishment associated with license renewal would be a
small fraction of the nuclear power plant site and would involve only land
that is controlled by the licensee.

Offsite land use

SMALL (Category 1). Offsite land use would not be affected by continued
operations and refurbishment associated with license renewal.

Offsite land use in
transmission line
right-of-ways
(ROWs)(c)

SMALL (Category 1). Use of transmission line ROWs from continued
operations and refurbishment associated with license renewal would
continue with no change in land use restrictions.

Visual Resources
Aesthetic impacts

SMALL (Category 1). No important changes to the visual appearance of
plant structures or transmission lines are expected from continued
operations and refurbishment associated with license renewal.

Air Quality
Air quality impacts

SMALL (Category 1). Air quality impacts from continued operations and
refurbishment associated with license renewal are expected to be small at
all plants. Emissions from emergency diesel generators and fire pumps and
routine operations of boilers used for space heating are minor. Impacts
from cooling tower particulate emissions have been small.
Emissions resulting from refurbishment activities at locations in or near air
quality nonattainment or maintenance areas would be short-lived and would
cease after these activities are completed. Operating experience has
shown that the scale of refurbishment activities has not resulted in
exceedance of the de minimis thresholds for criteria pollutants, and best
management practices, including fugitive dust controls and the imposition
of permit conditions in State and local air emissions permits, would ensure
conformance with applicable State or Tribal implementation plans.

Air quality effects of
transmission lines(c)

SMALL (Category 1). Production of ozone and oxides of nitrogen from
transmission lines is insignificant and does not contribute measurably to
ambient levels of these gases.

Noise
Noise impacts

SMALL (Category 1). Noise levels would remain below regulatory
guidelines for offsite receptors during continued operations and
refurbishment associated with license renewal.

Geologic Environment
Geology and soils

SMALL (Category 1). The impact of continued operations and
refurbishment activities on geology and soils would be small for all nuclear
power plants and would not change appreciably during the license renewal
term.

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Impact Finding(a)(b)

Environmental Issue
Surface Water Resources
Surface water use
and quality (noncooling system
impacts)

SMALL (Category 1). Impacts are expected to be small if best
management practices are employed to control soil erosion and spills.
Surface water use associated with continued operations and refurbishment
associated with license renewal would not increase significantly or would
be reduced if refurbishment occurs during a plant outage.

Altered current
patterns at intake and
discharge structures

SMALL (Category 1). Altered current patterns would be limited to the area
in the vicinity of the intake and discharge structures. These impacts have
been small at operating nuclear power plants.

Altered salinity
gradients

SMALL (Category 1). Effects on salinity gradients would be limited to the
area in the vicinity of the intake and discharge structures. These impacts
have been small at operating nuclear power plants.

Altered thermal
stratification of lakes

SMALL (Category 1). Effects on thermal stratification would be limited to
the area in the vicinity of the intake and discharge structures. These
impacts have been small at operating nuclear power plants.

Scouring caused by
discharged cooling
water

SMALL (Category 1). Scouring effects would be limited to the area in the
vicinity of the intake and discharge structures. These impacts have been
small at operating nuclear power plants.

Discharge of metals in
cooling system
effluent

SMALL (Category 1). Discharges of metals have not been found to be a
problem at operating nuclear power plants with cooling-tower-based heat
dissipation systems and have been satisfactorily mitigated at other plants.
Discharges are monitored and controlled as part of the National Pollutant
Discharge Elimination System (NPDES) permit process.

Discharge of biocides,
sanitary wastes, and
minor chemical spills

SMALL (Category 1). The effects of these discharges are regulated by
Federal and State environmental agencies. Discharges are monitored and
controlled as part of the NPDES permit process. These impacts have been
small at operating nuclear power plants.

Surface water use
conflicts (plants with
once-through cooling
systems)

SMALL (Category 1). These conflicts have not been found to be a problem
at operating nuclear power plants with once-through heat dissipation
systems.

Surface water use
conflicts (plants with
cooling ponds or
cooling towers using
makeup water from a
river)

SMALL or MODERATE (Category 2). Impacts could be of small or
moderate significance, depending on makeup water requirements, water
availability, and competing water demands.

Effects of dredging on
surface water quality

SMALL (Category 1). Dredging to remove accumulated sediments in the
vicinity of intake and discharge structures and to maintain barge shipping
has not been found to be a problem for surface water quality. Dredging is
performed under permit from the U.S. Army Corps of Engineers, and
possibly, from other State or local agencies.

Temperature effects
on sediment transport
capacity

SMALL (Category 1). These effects have not been found to be a problem
at operating nuclear power plants and are not expected to be a problem
during the license renewal term.

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Impact Finding(a)(b)

Environmental Issue
Groundwater Resources
Groundwater
contamination and
use (non-cooling
system impacts)

SMALL (Category 1). Extensive dewatering is not anticipated from
continued operations and refurbishment associated with license renewal.
Industrial practices involving the use of solvents, hydrocarbons, heavy
metals, or other chemicals, and/or the use of wastewater ponds or lagoons
have the potential to contaminate site groundwater, soil, and subsoil.
Contamination is subject to State or U.S. Environmental Protection Agency
(EPA) regulated cleanup and monitoring programs. The application of best
management practices for handling any materials produced or used during
these activities would reduce impacts.

Groundwater use
conflicts (plants that
withdraw less than
100 gallons per
minute [gpm])

SMALL (Category 1). Plants that withdraw less than 100 gpm are not
expected to cause any groundwater use conflicts.

Groundwater use
conflicts (plants that
withdraw more than
100 gallons per
minute [gpm])

SMALL, MODERATE, or LARGE (Category 2). Plants that withdraw more
than 100 gpm could cause groundwater use conflicts with nearby
groundwater users.

Groundwater use
conflicts (plants with
closed-cycle cooling
systems that withdraw
makeup water from a
river)

SMALL, MODERATE, or LARGE (Category 2). Water use conflicts could
result from water withdrawals from rivers during low-flow conditions, which
may affect aquifer recharge. The significance of impacts would depend on
makeup water requirements, water availability, and competing water
demands.

Groundwater quality
degradation resulting
from water
withdrawals

SMALL (Category 1). Groundwater withdrawals at operating nuclear
power plants would not contribute significantly to groundwater quality
degradation.

Groundwater quality
degradation (plants
with cooling ponds)

SMALL or MODERATE (Category 2). Sites with cooling ponds could
degrade groundwater quality. The significance of the impact would depend
on site-specific conditions including cooling pond water quality, site
hydrogeologic conditions (including the interaction of surface water and
groundwater), and the location, depth, and pump rate of water wells.

Radionuclides
released to
groundwater

SMALL or MODERATE (Category 2). Leaks of radioactive liquids from
plant components and pipes have occurred at numerous plants.
Groundwater protection programs have been established at all operating
nuclear power plants to minimize the potential impact from any inadvertent
releases. The magnitude of impacts would depend on site-specific
characteristics.

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Impact Finding(a)(b)

Environmental Issue
Terrestrial Resources
Non-cooling system
impacts on terrestrial
resources

SMALL, MODERATE, or LARGE (Category 2). The magnitude of effects
of continued nuclear power plant operation and refurbishment, unrelated to
operation of the cooling system, would depend on numerous site-specific
factors, including ecological setting, planned activities during the license
renewal term, and characteristics of the plants and animals present in the
area. Application of best management practices and other conservation
initiatives would reduce the potential for impacts.

Exposure of terrestrial
organisms to
radionuclides

SMALL (Category 1). Doses to terrestrial organisms from continued
nuclear power plant operation and refurbishment during the license renewal
term would be expected to remain well below U.S. Department of Energy
exposure guidelines developed to protect these organisms.

Cooling system
impacts on terrestrial
resources (plants with
once-through cooling
systems or cooling
ponds)

SMALL (Category 1). Continued operation of nuclear power plant cooling
systems during license renewal could cause thermal effluent additions to
receiving waterbodies, chemical effluent additions to surface water or
groundwater, impingement of waterfowl, disturbance of terrestrial plants
and wetlands from maintenance dredging, and erosion of shoreline habitat.
However, plants where these impacts have occurred successfully mitigated
the impact, and it is no longer of concern. These impacts are not expected
to be significant issues during the license renewal term.

Cooling tower impacts
on terrestrial plants

SMALL (Category 1). Continued operation of nuclear power plant cooling
towers could deposit particulates and water droplets or ice on vegetation
and lead to structural damage or changes in terrestrial plant communities.
However, nuclear power plants where these impacts occurred have
successfully mitigated the impact. These impacts are not expected to be
significant issues during the license renewal term.

Bird collisions with
plant structures and
transmission lines(c)

SMALL (Category 1). Bird mortalities from collisions with nuclear power
plant structures and in-scope transmission lines would be negligible for any
species and are unlikely to threaten the stability of local or migratory bird
populations or result in noticeable impairment of the function of a species
within the ecosystem. These impacts are not expected to be significant
issues during the license renewal term.

Water use conflicts
with terrestrial
resources (plants with
cooling ponds or
cooling towers using
makeup water from a
river)

SMALL or MODERATE (Category 2). Nuclear power plants could
consume water at rates that cause occasional or intermittent water use
conflicts with nearby and downstream terrestrial and riparian communities.
Such impacts could noticeably affect riparian or wetland species or alter
characteristics of the ecological environment during the license renewal
term. The one plant where impacts have occurred successfully mitigated
the impact. Impacts are expected to be small at most nuclear power plants
but could be moderate at some.

Transmission line
right-of-way (ROW)
management impacts
on terrestrial
resources(c)

SMALL (Category 1). In-scope transmission lines tend to occupy only
industrial-use or other developed portions of nuclear power plant sites and,
therefore, effects of ROW maintenance on terrestrial plants and animals
during the license renewal term would be negligible. Application of best
management practices would reduce the potential for impacts.

Electromagnetic field
effects on terrestrial
plants and animals(c)

SMALL (Category 1). In-scope transmission lines tend to occupy only
industrial-use or other developed portions of nuclear power plant sites and,
therefore, the effects of electromagnetic fields on terrestrial plants and
animals during the license renewal term would be negligible.

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Alternatives Including the Proposed Action

Impact Finding(a)(b)

Environmental Issue
Aquatic Resources
Impingement mortality
and entrainment of
aquatic organisms
(plants with oncethrough cooling
systems or cooling
ponds)

SMALL, MODERATE, or LARGE (Category 2). The impacts of
impingement mortality and entrainment would generally be small at nuclear
power plants with once-through cooling systems or cooling ponds that have
implemented best technology requirements for existing facilities under
Clean Water Act (CWA) Section 316(b). For all other plants, impacts could
be small, moderate, or large depending on characteristics of the cooling
water intake system, results of impingement and entrainment studies
performed at the plant, trends in local fish and shellfish populations, and
implementation of mitigation measures.

Impingement mortality
and entrainment of
aquatic organisms
(plants with cooling
towers)

SMALL (Category 1). No significant impacts on aquatic populations
associated with impingement mortality and entrainment at nuclear power
plants with cooling towers have been reported, including effects on fish and
shellfish from direct mortality, injury, or other sublethal effects. Impacts
during the license renewal term would be similar and small. Further, the
effects of these cooling water intake systems would be mitigated through
adherence to NPDES permit conditions established pursuant to CWA
Section 316(b).

Entrainment of
phytoplankton and
zooplankton

SMALL (Category 1). Entrainment has not resulted in noticeable impacts
on phytoplankton or zooplankton populations near operating nuclear power
plants. Impacts during the license renewal term would be similar and small.
Further, effects would be mitigated through adherence to NPDES permit
conditions established pursuant to CWA Section 316(b).

Effects of thermal
effluents on aquatic
organisms (plants
with once-through
cooling systems or
cooling ponds)

SMALL, MODERATE, or LARGE (Category 2). Acute, sublethal, and
community-level effects of thermal effluents on aquatic organisms would
generally be small at nuclear power plants with once-through cooling
systems or cooling ponds that adhere to State water quality criteria or that
have and maintain a valid CWA Section 316(a) variance. For all other
plants, impacts could be small, moderate, or large depending on sitespecific factors, including ecological setting of the plant; characteristics of
the cooling system and effluent discharges; and characteristics of the fish,
shellfish, and other aquatic organisms present in the area.

Effects of thermal
effluents on aquatic
organisms (plants
with cooling towers)

SMALL (Category 1). Acute, sublethal, and community-level effects of
thermal effluents have not resulted in noticeable impacts on aquatic
communities at nuclear power plants with cooling towers. Impacts during
the license renewal term would be similar and small. Further, effects would
be mitigated through adherence to State water quality criteria or CWA
Section 316(a) variances.

Infrequently reported
effects of thermal
effluents

SMALL (Category 1). Continued operation of nuclear power plant cooling
systems could result in certain infrequently reported thermal impacts,
including cold shock, thermal migration barriers, accelerated maturation of
aquatic insects, proliferation of aquatic nuisance organisms, depletion of
dissolved oxygen, gas supersaturation, eutrophication, and increased
susceptibility of exposed fish and shellfish to predation, parasitism, and
disease. Most of these effects have not been reported at operating nuclear
power plants. Plants that have experienced these impacts successfully
mitigated the impact, and it is no longer of concern. Infrequently reported
thermal impacts are not expected to be significant issues during the license
renewal term.

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Alternatives Including the Proposed Action

Impact Finding(a)(b)

Environmental Issue
Effects of
nonradiological
contaminants on
aquatic organisms

SMALL (Category 1). Heavy metal leaching from condenser tubes was an
issue at several operating nuclear power plants. These plants successfully
mitigated the issue, and it is no longer of concern. Cooling system effluents
would be the primary source of nonradiological contaminants during the
license renewal term. Implementation of best management practices and
adherence to NPDES permit limitations would minimize the effects of these
contaminants on the aquatic environment.

Exposure of aquatic
organisms to
radionuclides

SMALL (Category 1). Doses to aquatic organisms from continued nuclear
power plant operation and refurbishment during the license renewal term
would be expected to remain well below U.S. Department of Energy
exposure guidelines developed to protect these organisms.

Effects of dredging on
aquatic resources

SMALL (Category 1). Dredging at nuclear power plants is expected to
occur infrequently, would be of relatively short duration, and would affect
relatively small areas. Continued operation of many plants may not require
any dredging. Adherence to best management practices and CWA
Section 404 permit conditions would mitigate potential impacts at plants
where dredging is necessary to maintain function or reliability of cooling
systems. Dredging is not expected to be a significant issue during the
license renewal term.

Water use conflicts
with aquatic
resources (plants with
cooling ponds or
cooling towers using
makeup water from a
river)

SMALL or MODERATE (Category 2). Nuclear power plants could
consume water at rates that cause occasional or intermittent water use
conflicts with nearby and downstream aquatic communities. Such impacts
could noticeably affect aquatic plants or animals or alter characteristics of
the ecological environment during the license renewal term. The one plant
where impacts have occurred successfully mitigated the impact. Impacts
are expected to be small at most nuclear power plants but could be
moderate at some.

Non-cooling system
impacts on aquatic
resources

SMALL (Category 1). No significant impacts on aquatic resources
associated with landscape and grounds maintenance, stormwater
management, or ground-disturbing activities at operating nuclear power
plants have been reported. Impacts from continued operation and
refurbishment during the license renewal term would be similar and small.
Application of best management practices and other conservation initiatives
would reduce the potential for impacts.

Impacts of
transmission line
right-of-way (ROW)
management on
aquatic resources(c)

SMALL (Category 1). In-scope transmission lines tend to occupy only
industrial-use or other developed portions of nuclear power plant sites and,
therefore, the effects of ROW maintenance on aquatic plants and animals
during the license renewal term would be negligible. Application of best
management practices would reduce the potential for impacts.

Federally Protected Ecological Resources
Endangered Species
Act: federally listed
species and critical
habitats under U.S.
Fish and Wildlife
Service jurisdiction

NUREG-1437, Revision 2

(Category 2). The potential effects of continued nuclear power plant
operation and refurbishment on federally listed species and critical habitats
would depend on numerous site-specific factors, including the ecological
setting; listed species and critical habitats present in the action area; and
plant-specific factors related to operations, including water withdrawal,
effluent discharges, and other ground-disturbing activities. Consultation
with the U.S. Fish and Wildlife Service under Endangered Species Act
Section 7(a)(2) would be required if license renewal may affect listed
species or critical habitats under this agency’s jurisdiction.

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Alternatives Including the Proposed Action

Environmental Issue

Impact Finding(a)(b)

Endangered Species
Act: federally listed
species and critical
habitats under
National Marine
Fisheries Service
jurisdiction

(Category 2). The potential effects of continued nuclear power plant
operation and refurbishment on federally listed species and critical habitats
would depend on numerous site-specific factors, including the ecological
setting; listed species and critical habitats present in the action area; and
plant-specific factors related to operations, including water withdrawal,
effluent discharges, and other ground-disturbing activities. Consultation
with the National Marine Fisheries Service under Endangered Species Act
Section 7(a)(2) would be required if license renewal may affect listed
species or critical habitats under this agency’s jurisdiction.

Magnuson-Stevens
Act: essential fish
habitat

(Category 2). The potential effects of continued nuclear power plant
operation and refurbishment on essential fish habitat would depend on
numerous site-specific factors, including the ecological setting; essential
fish habitat present in the area, including habitats of particular concern; and
plant-specific factors related to operations, including water withdrawal,
effluent discharges, and other activities that may affect aquatic habitats.
Consultation with the National Marine Fisheries Service under MagnusonStevens Act Section 305(b) would be required if license renewal could
result in adverse effects to essential fish habitat.

National Marine
Sanctuaries Act:
sanctuary resources

(Category 2). The potential effects of continued nuclear power plant
operation and refurbishment on sanctuary resources would depend on
numerous site-specific factors, including the ecological setting; national
marine sanctuaries present in the area; and plant-specific factors related to
operations, including water withdrawal, effluent discharges, and other
activities that may affect aquatic habitats. Consultation with the Office of
National Marine Sanctuaries under National Marine Sanctuaries Act
Section 304(d) would be required if license renewal could destroy, cause
the loss of, or injure sanctuary resources.

Historic and Cultural Resources
Historic and cultural
resources(c)

(Category 2). Impacts from continued operations and refurbishment on
historic and cultural resources located onsite and in the transmission line
ROW are analyzed on a plant-specific basis. The NRC will perform a
National Historic Preservation Act (NHPA) Section 106 review, in
accordance with 36 CFR Part 800 which includes consultation with the
State and Tribal Historic Preservation Officers, Indian Tribes, and other
interested parties.

Socioeconomics
Employment and
income, recreation
and tourism

SMALL (Category 1). Although most nuclear plants have large numbers of
employees with higher than average wages and salaries, employment,
income, recreation, and tourism impacts from continued operations and
refurbishment associated with license renewal are expected to be small.

Tax revenue

SMALL (Category 1). Nuclear plants provide tax revenue to local
jurisdictions in the form of property tax payments, payments in lieu of tax
(PILOT), or tax payments on energy production. The amount of tax revenue
paid during the license renewal term as a result of continued operations
and refurbishment associated with license renewal is not expected to
change.

Community services
and education

SMALL (Category 1). Changes resulting from continued operations and
refurbishment associated with license renewal to local community and
educational services would be small. With little or no change in employment
at the licensee’s plant, value of the power plant, payments on energy

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Alternatives Including the Proposed Action

Impact Finding(a)(b)

Environmental Issue

production, and PILOT payments expected during the license renewal term,
community and educational services would not be affected by continued
power plant operations.
Population and
housing

SMALL (Category 1). Changes resulting from continued operations and
refurbishment associated with license renewal to regional population and
housing availability and value would be small. With little or no change in
employment at the licensee’s plant expected during the license renewal
term, population and housing availability and values would not be affected
by continued power plant operations.

Transportation

SMALL (Category 1). Changes resulting from continued operations and
refurbishment associated with license renewal to traffic volumes would be
small.

Human Health
Radiation exposures
to plant workers

SMALL (Category 1). Occupational doses from continued operations and
refurbishment associated with license renewal are expected to be within the
range of doses experienced during the current license term, and would
continue to be well below regulatory limits.

Radiation exposures
to the public

SMALL (Category 1). Radiation doses to the public from continued
operations and refurbishment associated with license renewal are expected
to continue at current levels, and would be well below regulatory limits.

Chemical hazards

SMALL (Category 1). Chemical hazards to plant workers resulting from
continued operations and refurbishment associated with license renewal
are expected to be minimized by the licensee implementing good industrial
hygiene practices as required by permits and Federal and State
regulations. Chemical releases to the environment and the potential for
impacts to the public are expected to be minimized by adherence to
discharge limitations of NPDES and other permits.

Microbiological
hazards to plant
workers

SMALL (Category 1). Occupational health impacts are expected to be
controlled by continued application of accepted industrial hygiene practices
to minimize worker exposures as required by permits and Federal and
State regulations.

Microbiological
hazards to the public

SMALL, MODERATE, or LARGE (Category 2). These microorganisms
are not expected to be a problem at most operating plants except possibly
at plants using cooling ponds, lakes, canals, or that discharge to publicly
accessible surface waters. Impacts would depend on site-specific
characteristics.

Electromagnetic fields
(EMFs)(c)

Uncategorized (Uncertain impact). Studies of 60-Hz EMFs have not
uncovered consistent evidence linking harmful effects with field exposures.
EMFs are unlike other agents that have a toxic effect (e.g., toxic chemicals
and ionizing radiation) in that dramatic acute effects cannot be forced and
longer-term effects, if real, are subtle. Because the state of the science is
currently inadequate, no generic conclusion on human health impacts is
possible.

Physical occupational
hazards

SMALL (Category 1). Occupational safety and health hazards are generic
to all types of electrical generating stations, including nuclear power plants,
and are of small significance if the workers adhere to safety standards and
use protective equipment as required by Federal and State regulations.

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Alternatives Including the Proposed Action

Impact Finding(a)(b)

Environmental Issue
Electric shock
hazards(c)

SMALL, MODERATE, or LARGE (Category 2). Electrical shock potential
is of small significance for transmission lines that are operated in
adherence with the National Electrical Safety Code (NESC). Without a
review of conformance with NESC criteria of each nuclear power plant’s
in-scope transmission lines, it is not possible to determine the significance
of the electrical shock potential.

Postulated Accidents
Design-basis
accidents

SMALL (Category 1). The NRC staff has concluded that the environmental
impacts of design-basis accidents are of small significance for all plants.

Severe accidents(d)

SMALL (Category 1). The probability-weighted consequences of
atmospheric releases, fallout onto open bodies of water, releases to
groundwater, and societal and economic impacts from severe accidents are
small for all plants. Severe accident mitigation alternatives do not warrant
further plant-specific analysis because the demonstrated reductions in
population dose risk and continued severe accident regulatory
improvements substantially reduce the likelihood of finding cost-effective
significant plant improvements.

Environmental Justice
Impacts on minority
populations, lowincome populations,
and Indian Tribes

(Category 2). Impacts on minority populations, low-income populations,
Indian Tribes, and subsistence consumption resulting from continued
operations and refurbishment associated with license renewal will be
addressed in nuclear plant-specific reviews.

Waste Management
Low-level waste
storage and disposal

SMALL (Category 1). The comprehensive regulatory controls that are in
place and the low public doses being achieved at reactors ensure that the
radiological impacts on the environment would remain small during the
license renewal term.

Onsite storage of
spent nuclear fuel

During the license renewal term, SMALL (Category 1). The expected
increase in the volume of spent fuel from an additional 20 years of
operation can be safely accommodated onsite during the license renewal
term with small environmental impacts through dry or pool storage at all
plants.
For the period after the licensed life for reactor operations, the impacts of
onsite storage of spent nuclear fuel during the continued storage period are
discussed in NUREG-2157 and as stated in § 51.23(b), shall be deemed
incorporated into this issue.

Offsite radiological
impacts of spent
nuclear fuel and highlevel waste disposal

(Category 1). For the high-level waste and spent-fuel disposal component
of the fuel cycle, the EPA established a dose limit of 0.15 mSv (15 millirem)
per year for the first 10,000 years and 1.0 mSv (100 millirem) per year
between 10,000 years and 1 million years for offsite releases of
radionuclides at the proposed repository at Yucca Mountain, Nevada.
The Commission concludes that the impacts would not be sufficiently large
to require the NEPA conclusion, for any plant, that the option of extended
operation under 10 CFR part 54 should be eliminated. Accordingly, while
the Commission has not assigned a single level of significance for the
impacts of spent fuel and high-level waste disposal, this issue is considered
Category 1.

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Alternatives Including the Proposed Action

Environmental Issue

Impact Finding(a)(b)

Mixed-waste storage
and disposal

SMALL (Category 1). The comprehensive regulatory controls and the
facilities and procedures that are in place ensure proper handling and
storage, as well as negligible doses and exposure to toxic materials for the
public and the environment at all plants. License renewal would not
increase the small, continuing risk to human health and the environment
posed by mixed waste at all plants. The radiological and nonradiological
environmental impacts of long-term disposal of mixed waste from any
individual plant at licensed sites are small.

Nonradioactive waste
storage and disposal

SMALL (Category 1). No changes to systems that generate nonradioactive
waste are anticipated during the license renewal term. Facilities and
procedures are in place to ensure continued proper handling, storage, and
disposal, as well as negligible exposure to toxic materials for the public and
the environment at all plants.

Greenhouse Gas Emissions and Climate Change
Greenhouse gas
impacts on climate
change

SMALL (Category 1). Greenhouse gas impacts on climate change from
continued operations and refurbishment associated with license renewal
are expected to be small at all plants. Greenhouse gas emissions from
routine operations of nuclear power plants are typically very minor, because
such plants, by their very nature, do not normally combust fossil fuels to
generate electricity.
Greenhouse gas emissions from construction vehicles and other motorized
equipment for refurbishment activities would be intermittent and temporary,
restricted to the refurbishment period. Worker vehicle greenhouse gas
emissions for refurbishment would be similar to worker vehicle emissions
from normal nuclear power plant operations.

Climate change
impacts on
environmental
resources

(Category 2). Climate change can have additive effects on environmental
resource conditions that may also be directly impacted by continued
operations and refurbishment during the license renewal term. The effects
of climate change can vary regionally and climate change information at the
regional and local scale is necessary to assess trends and the impacts on
the human environment for a specific location. The impacts of climate
change on environmental resources during the license renewal term are
location-specific and cannot be evaluated generically.

Cumulative Effects
Cumulative effects

NUREG-1437, Revision 2

(Category 2). Cumulative effects or impacts of continued operations and
refurbishment associated with license renewal must be considered on a
plant-specific basis. The effects depend on regional resource
characteristics, the incremental resource-specific effects of license renewal,
and the cumulative significance of other factors affecting the environmental
resource.

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Alternatives Including the Proposed Action

Impact Finding(a)(b)

Environmental Issue
Uranium Fuel Cycle
Offsite radiological
impacts—individual
impacts from other
than the disposal of
spent fuel and highlevel waste

SMALL (Category 1). The impacts to the public from radiological
exposures have been considered by the Commission in Table S-3 of this
part. Based on information in the GEIS, impacts to individuals from
radioactive gaseous and liquid releases, including radon-222 and
technetium-99, would remain at or below the NRC’s regulatory limits.

Offsite radiological
impacts—collective
impacts from other
than the disposal of
spent fuel and highlevel waste

(Category 1). There are no regulatory limits applicable to collective doses
to the general public from fuel-cycle facilities. The practice of estimating
health effects on the basis of collective doses may not be meaningful. All
fuel-cycle facilities are designed and operated to meet the applicable
regulatory limits and standards. The Commission concludes that the
collective impacts are acceptable.
The Commission concludes that the impacts would not be sufficiently large
to require the NEPA conclusion, for any plant, that the option of extended
operation under 10 CFR Part 54 should be eliminated. Accordingly, while
the Commission has not assigned a single level of significance for the
collective impacts of the uranium fuel cycle, this issue is considered
Category 1.

Nonradiological
impacts of the
uranium fuel cycle

SMALL (Category 1). The nonradiological impacts of the uranium fuel
cycle resulting from the renewal of an operating license for any plant would
be small.

Transportation

SMALL (Category 1). The impacts of transporting materials to and from
uranium-fuel-cycle facilities on workers, the public, and the environment are
expected to be small.

Termination of Nuclear Power Plant Operations and Decommissioning
Termination of plant
operations and
decommissioning

SMALL (Category 1). License renewal is expected to have a negligible
effect on the impacts of terminating operations and decommissioning on all
resources.

CFR = Code of Federal Regulations; CWA = Clean Water Act; EMF = electromagnetic field; EPA = U.S.
Environmental Protection Agency; GEIS = generic environmental impact statement; gpm = gallon(s) per minute;
Hz = hertz; NEPA = National Environmental Policy Act; NESC = National Electrical Safety Code; NHPA = National
Historic Preservation Act; NPDES = National Pollutant Discharge Elimination System; NRC = U.S. Nuclear
Regulatory Commission; PILOT = payments in lieu of tax; ROW = right-of-way.
(a) Supports the finding codified in Table B-1 of Appendix B to Subpart A of 10 CFR Part 51. Where appropriate, a
significance level (i.e., SMALL, MODERATE, or LARGE, or a range) has been assigned to the impacts. These
levels are used for describing the environmental impacts of the proposed action (license renewal), as well as for
the impacts of a range of reasonable alternatives to the proposed action. Resource-specific effects or impact
definitions from applicable environmental laws and executive orders, other than SMALL, MODERATE, and
LARGE, are used where appropriate.
(b) The technical bases for these issues and findings in the LR GEIS have been revised to fully account for the
impacts of initial LR and SLR.
(c) This issue applies only to the in-scope portion of electric power transmission lines, which are defined as
transmission lines that connect the nuclear power plant to the substation where electricity is fed into the regional
power distribution system and transmission lines that supply power to the nuclear plant from the grid.
(d) Although the NRC does not anticipate any license renewal applications for nuclear power plants for which a
previous severe accident mitigation design alternative (SAMDA) or severe accident mitigation alternative (SAMA)
analysis has not been performed, alternatives to mitigate severe accidents must be considered for all plants that
have not considered such alternatives and would be the functional equivalent of a Category 2 issue requiring
plant-specific analysis.

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NUREG-1437, Revision 2

Alternatives Including the Proposed Action

2.2

No Action Alternative

The no action alternative represents a decision by the NRC not to renew the operating license
of a nuclear power plant beyond the current operating license term. At some point, all nuclear
plants will terminate operations and undergo decommissioning. Under the no action alternative,
plant operations would terminate at or before the end of the current license term.
Not renewing the license and ceasing operation under the no action alternative may lead to a
variety of potential outcomes, but these would be essentially the same regardless of whether
operations cease at the expiration of the original operating license or at the expiration of a
renewed license. Expiration of a license will require the reactor to ultimately undergo
decommissioning. The no action alternative, unlike the other alternatives, does not expressly
meet the purpose and need of the proposed action, because it does not provide a means of
delivering baseload power to meet future electric system needs. The no action alternative on its
own would likely create a need for replacement energy.

2.3

Alternative Energy Sources

Alternative energy sources may potentially be capable of meeting the purpose and need of the
proposed action (license renewal). Accordingly, these alternative energy sources could provide
additional options that allow for baseload power-generation capability beyond the term of the
current nuclear power plant operating license to meet future system power-generating needs, as
such needs may be determined by State, utility, and, where authorized, Federal (other than
NRC) decisionmakers. A reasonable alternative must be commercially viable on a utility scale
and operational prior to the expiration of the reactor’s operating license, or expected to become
commercially viable on a utility scale and operational prior to the expiration of the reactor’s
operating license. The NRC considered the following alternative energy sources in this
LR GEIS, as detailed in Appendix D:
• fossil fuel energy technologies, including natural gas, coal, and oil
• new nuclear energy technologies, including large light water reactors and small modular
reactors
• renewable energy technologies, including solar, wind, hydroelectric, biomass, geothermal,
ocean wave and current, and fuel cells
• non-power generating technologies, including demand-side management, delayed retirement
of other generating facilities, and purchased power
The NRC has updated this LR GEIS to incorporate the latest information on alternative energy
sources, but it is inevitable that rapidly evolving technologies will outpace the information
presented. As technologies improve, the NRC expects that some alternative energy sources not
currently viable for replacing or offsetting the power generated by a nuclear power plant may
become viable at some time in the future. The NRC will make that determination during
plant-specific license renewal reviews, as documented in plant-specific SEISs to this LR GEIS.
The amount of replacement power generated or offset must equal the baseload capacity
previously supplied by the nuclear plant and reliably operate at or near the nuclear plant’s
demonstrated capacity factor.1
1

The capacity factor is the ratio of the amount of electric energy produced by an electric generator over a
given period of time to the amount of electric energy the same generator would have produced had it
operated at its full, rated capacity over the same period of time.

NUREG-1437, Revision 2

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Alternatives Including the Proposed Action
If the need arises to replace or offset the generating capacity of a nuclear reactor, power could
be provided by a suite of individual alternative energy sources. Power could also be provided
using combinations of alternative energy sources, as well as by instituting demand-side
management measures, delaying the scheduled retirement of one or more existing power
plants, or purchasing an equivalent amount of power. The number of possible combinations of
alternative energy sources that could replace or offset the generating capacity of a nuclear
power plant is potentially unlimited. Based on this, the NRC has only evaluated individual
energy sources rather than combinations of energy sources in this LR GEIS. However,
combinations of energy sources may be considered during plant-specific license renewal
reviews. As discussed in Chapter 1, the NRC does not engage in energy-planning decisions
and makes no judgment about which alternative energy source(s) evaluated would be chosen in
any given case.

2.4

Comparison of Alternatives

This section provides a summary comparison of the environmental impacts of the proposed
action (license renewal), and alternatives to the proposed action (including the no action
alternative, and possible fossil fuel, new nuclear, and renewable energy alternatives for
replacing an existing nuclear power plant’s generating capacity). Table 2.4-1 through
Table 2.4-5 provide an overview of the general findings of the impact analyses for the proposed
action (presented in Chapter 4), and for alternatives to the proposed action (presented in
Appendix D). Impacts related to construction (Table 2.4-1), operations (Table 2.4-2), postulated
accidents (Table 2.4-3), termination of nuclear power plant operations and decommissioning
(Table 2.4-4), and the fuel cycle (Table 2.4-5) are provided. In each of these tables, important
aspects of each alternative that serve as the basis of the assessment are identified as well as
the magnitude of the anticipated impact in each resource area. These tables also provide a
summary of anticipated impacts from potential non-power generating approaches for offsetting a
nuclear power plant’s generating capacity (demand-side management, delayed retirement, and
purchased power). Such non-power generating approaches are most likely to be considered
only as components of plant-specific combination alternatives in plant-specific SEISs prepared
to evaluate the environmental impacts of renewing a nuclear power plant’s operating license.
The non-power generating approaches would generally have impacts that will depend on the
source used to compensate for the lost energy generation. Accordingly, impacts from these
non-power generating approaches are not evaluated further in this LR GEIS. More detailed
analyses incorporating relevant site-specific factors (as well as the future state of technology
and, possibly, other reasonable alternatives) will be provided in each plant-specific SEIS.
Further, each plant-specific SEIS must analyze the impacts of the proposed action (license
renewal) as well as a range of reasonable alternatives to provide replacement energy.
According to the White House Council on Environmental Quality, reasonable alternatives
comprise “those that are practical or feasible from the technical and economic standpoint and
using common sense” (46 FR 18026). Replacement energy alternatives may require the
construction of a new power plant and possibly the modification of the electric transmission grid.
New power plants would also have operational impacts that may or may not be equivalent in
nature and/or extent to the operational impacts of the nuclear plant. License renewal would not
require major construction, and operational impacts would not change beyond what is currently
being experienced at the nuclear plant. Other alternatives that would not have construction or
operational impacts include conservation and energy efficiency, delayed retirement, and
purchased power.

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Alternatives Including the Proposed Action
The operational impacts of license renewal are comparable to replacement power alternatives
and some renewable energy alternatives in some resource areas (e.g., socioeconomics), but
quite different in other resource areas (e.g., air emissions, fuel cycle, land use, and water
consumption). Some renewable energy alternatives (wind, ocean wave, and ocean current
alternatives) have very few operational impacts, while others (biomass combustion and
conventional hydropower) can have considerable operational impacts. Some renewable energy
alternatives (wind and solar) have relatively low but regionally variable capacity factors while
others (e.g., conventional hydropower and geothermal) can exhibit capacity factors at or near
those of a nuclear power plant.
The proposed action and alternatives differ in other respects, including the consequences of
accidents. The proposed action and new nuclear energy alternatives all may have low
probability but potentially high-consequence accidents in comparison to non-nuclear
alternatives.

NUREG-1437, Revision 2

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Table 2.4-1

Construction under the Proposed Action and Alternatives – Assessment Basis and Nature of Impacts

Proposed Action(a)

No Action Alternative

Minor construction
No construction at
projects (refurbishment) nuclear plant sites if
associated with the
license renewal is denied.
proposed action. Original
nuclear plant construction
is not part of the
proposed action.

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Demand-Side
Management

Purchased Power
and Delayed Retirement

Major construction projects would be
required to build replacement fossil
fuel, nuclear, or renewable energy
generation capacity. Impacts would
vary according to the specific
alternative technology selected and
site-specific resource conditions that
would be reviewed under separate
environmental review processes,
depending on the activity’s location
and proponent. Impacts at
brownfield sites would be smaller
than at greenfield sites. Power may
also be replaced by a portfolio of
alternative technologies; in such
cases, impacts would be additive
among portfolio components,
occurring at each facility
commensurate with the technology
and the amount of replacement
power it provides.

Little or no construction
would be associated with
DSM programs
implemented to offset lost
generation capacity.

No construction would
occur from purchased
power or delayed
retirements of existing
non-nuclear plants if
available excess capacity
is sufficient to offset
losses. Construction
could occur in instances
where expansions of the
capacity of the alternative
generation source to
meet power purchase
agreements or
modifications to the
transmission grid were
required to bring the
imported power to the
load centers affected by
reactor retirement.

NUREG-1437, Revision 2

DSM = demand-side management.
(a) Refer to Table 2.1-1 for a more detailed presentation of the impacts of construction (likely refurbishments) under the proposed action. These impacts are
discussed in detail in Chapter 4.

Alternatives Including the Proposed Action

Fossil, New Nuclear, and
Renewable Energy Alternatives

Operations under the Proposed Action and Alternatives – Assessment Basis and Nature of Impacts

Proposed Action(a)

No Action Alternative

Continued operations
under the proposed
action would be
comparable to what is
already occurring at the
nuclear plant.

Termination of reactor
operations would occur
sooner than under the
proposed action. After
reactor shutdown,
some systems would
continue operating but
at reduced levels.

Fossil, New Nuclear, and Renewable
Energy Alternatives

Demand-Side
Management

Operation of a new fossil fuel energy,
nuclear, or renewable energy facility would
introduce new impacts to the facility site and
vicinity. Impacts would vary according to sitespecific resource conditions that would be
reviewed under separate NEPA
assessments. If lost power capacity is
replaced with a portfolio of alternatives,
impacts would be additive, occurring at each
of the facilities within the portfolio based on
the nature of the technology employed and
commensurate with the amount of power
produced. Impacts at brownfield sites may be
less than at greenfield sites.

No new operational
impacts are likely to
result from DSM
programs implemented
to offset lost generation
capacity. Existing
operational impacts from
current generation
sources may be
lessened if greater load
reductions result.

Purchased Power
and Delayed
Retirement

2-20

Impacts would occur
in areas where
purchased power is
produced or where
delayed retirements
of existing nonnuclear plants
occur. Impact
magnitude would be
reflective of the type
of generating
technology
employed and the
amount of power
required.

Fossil fuel energy alternatives would have
similar operational impacts as the proposed
action, nuclear, and some renewable
alternatives (e.g., biomass), but would
produce more air emissions. New nuclear
energy alternatives would have operational
impacts similar to those of fossil fuel and
some renewable technologies but would
produce fewer air emissions than fossil fuel
and biomass technologies. Renewable
technologies differ greatly in terms of
operational impacts.
DSM = demand-side management.
(a) Refer to Table 2.1-1 for a more detailed presentation of the impacts of operations under the proposed action. These impacts are discussed in detail in
Chapter 4.

Alternatives Including the Proposed Action

NUREG-1437, Revision 2

Table 2.4-2

Table 2.4-3

Postulated Accidents under the Proposed Action and Alternatives – Assessment Basis and Impact Magnitude

Proposed Action(a)

2-21

Fossil, New Nuclear, and Renewable
Energy Alternatives

Demand-Side
Management

Purchased Power and
Delayed Retirement

Plant shutdown
would occur
sooner than under
the proposed
action. A reduction
in accident risk
would occur
sooner.

Accidents associated with fossil fuel
energy facilities would have short-term,
localized effects. Accidents associated
with nuclear energy would be similar to
those of the proposed action. Accidents
associated with biomass facilities would
be comparable to those of fossil fuel
energy facilities. Accidents associated with
hydropower (e.g., dam collapse) could
have large, far-reaching effects. Accidents
associated with coal combustion residue
handling and storage could also have
large, far-reaching effects. Impacts from
accidents associated with other renewable
energy technologies would be localized
and generally inconsequential.

No accidents are
associated with
DSM measures
aside from
occupational
hazards for
those who install
or implement
them.

Impacts would occur in areas
where purchased power is
produced or where delayed
retirements of existing nonnuclear plants occur. The
nature and magnitude of the
impact would depend on the
technology used to produce
the power and characteristics
of the plant site. If power is
purchased from existing
generating facilities with
excess capacity, little change
in impact would be expected.
Additional impacts may result
from required expansions or
modifications of transmission
infrastructures.

DSM = demand-side management.
(a) Refer to Table 2.1-1 for a more detailed presentation of the impacts of accidents under the proposed action. These impacts are discussed in detail in
Section 4.9.1.2.

NUREG-1437, Revision 2

Alternatives Including the Proposed Action

Postulated accidents
associated with continued
operations under the license
renewal term include designbasis accidents and severe
accidents. The impacts take
into consideration the low
probability of an accident
occurring. Design-basis
accidents would have a small
impact. Severe accidents
would likely have larger
consequences than designbasis accidents, but the
probability-weighted
consequences (i.e., the
probability of occurrence of the
accident multiplied by the
consequence if the accident
occurred) would be SMALL for
all plants.

No Action
Alternative

Termination of Nuclear Power Plant Operations and Decommissioning under the Proposed Action and
Alternatives – Assessment Basis and Nature of Impacts

Proposed Action(a)

2-22

Termination of
reactor operations
and
decommissioning
would occur
regardless of the
proposed action.
The proposed action
would not contribute
substantially to the
impacts from the
termination of
reactor operations
and
decommissioning.

No Action
Alternative

Fossil, New Nuclear, and Renewable
Energy Alternatives

The no action
alternative would
not contribute to
the impacts of
terminating reactor
operations and
decommissioning.

Termination of power plant operations and
decommissioning of a fossil fuel, nuclear, or
renewable energy facility would result in
short-term impacts during facility
dismantlement and longer-term waste
management impacts. Impacts would vary
according to site-specific resource
conditions. The NRC staff’s analysis
assumes that dams would remain in place
for flood control after hydroelectric power
generation ceases. Impacts at brownfield
sites may be less than at greenfield sites.

Demand-Side Management
No termination of operations
and decommissioning impacts
are anticipated to result from
energy conservation programs
implemented to offset lost
generation capacity.

Purchased Power
and Delayed
Retirement
Because existing
facilities would be
used to produce
purchased power, no
termination of
operations and
decommissioning
impacts would be
associated with this
alternative. Delaying
retirements of existing
non-nuclear plants
would similarly delay
impacts associated
with termination of
operations and
decommissioning.

(a) Refer to Table 2.1-1 for a more detailed presentation of the impacts of decommissioning under the proposed action. These impacts are discussed in detail in
Section 4.14.2.

Alternatives Including the Proposed Action

NUREG-1437, Revision 2

Table 2.4-4

Table 2.4-5

Fuel Cycle under the Proposed Action and Alternatives – Assessment Basis and Nature of Impacts

Proposed Action(a)
During the license
renewal term, the
proposed action would
result in the need for
continued mining and
milling of uranium; fuel
fabrication; and
storage, transport, and
disposal of radioactive
and other wastes.

No Action
Alternative
The no action
alternative would
reduce the need for
nuclear fuel and
reduce the
environmental
impacts associated
with the uranium fuel
cycle.

Fossil, New Nuclear, and Renewable Energy
Alternatives

Demand-Side
Management

2-23

The fuel-cycle
impacts
associated with
power purchases
would depend on
the mix of
generating
sources that are
used to produce
purchased power.
The fuel-cycle
impacts
associated with
delayed retirement
would depend on
the specific fuel
type associated
with the existing
non-nuclear plant.

(a) Refer to Table 2.1-1 for a more detailed presentation of the impacts of the fuel cycle under the proposed action. These impacts are discussed in detail in
Section 4.14.1.

NUREG-1437, Revision 2

Alternatives Including the Proposed Action

The fuel cycle of fossil fuel energy alternatives includes There is no fuel cycle
the extraction of coal (mining) or natural gas (drilling
associated with
and fracking); fuel cleanup; transport of extracted fuel; energy conservation.
and storage, transport, and disposal of combustion
waste. Impacts would depend on characteristics of
extraction sites and fuels. The new nuclear energy
alternatives would have impacts similar to those of the
proposed action. Of renewables, only certain biomass
technologies (e.g., crop residues, forest products) have
a well-defined fuel cycle. Biomass projects that involve
growing, harvesting, and processing of plant materials
would have impacts associated with producing and
transporting biomass fuel and storage and disposal of
combustion waste. Impacts would depend on the
nature of the biomass being produced, the
characteristics of areas used to produce fuel, and the
technology used to convert the biomass to energy.

Purchased
Power and
Delayed
Retirement

Alternatives Including the Proposed Action
The termination of nuclear power plant operations and decommissioning impacts at nuclear
plant sites would eventually occur regardless of a decision to renew their licenses. Thus, in this
analysis, those impacts are not attributed to the proposed action, and the incremental effects of
the proposed action on the impacts from the termination of nuclear power plant operations and
decommissioning would be SMALL for all resource areas. Impacts from the decommissioning of
a new nuclear power reactor would be similar to those from the decommissioning of existing
reactors.
Fuel-cycle impacts have been evaluated for license renewal and were found to be SMALL for all
resource areas, except for offsite radiological impacts—collective impacts from other than the
disposal of spent fuel and high-level waste, which are acceptable (see Section 4.14.1,
“Environmental Consequences of the Uranium Fuel Cycle” for information about this issue).
Fossil-fueled alternatives may have larger fuel-cycle impacts (mostly associated with land
disturbance at fuel extraction sites), while other alternatives have no fuel-cycle impacts
(renewable alternatives such as wind, wave, current, or solar alternatives do not require fuel).

NUREG-1437, Revision 2

2-24

3

AFFECTED ENVIRONMENT

For purposes of the evaluation in this revision of NUREG-1437, Generic Environmental Impact
Statement for License Renewal of Nuclear Plants (LR GEIS), the “affected environment” is the
environment that currently exists at and around operating U.S. commercial nuclear power
plants. Because existing conditions are at least partially the result of past construction and
ongoing operations at the nuclear plants, as well as reasonably foreseeable environmental
trends, the impacts of these past and ongoing activities and how they have shaped the
environment are summarized here. Thus, it is this existing environment that composes the
environmental baseline against which potential environmental effects (impacts) of license
renewal are evaluated. The impacts of continued operations and any refurbishment during the
license renewal (initial license renewal [initial LR] or subsequent license renewal [SLR]) term
that are presented in Chapter 4 are incremental to these baseline conditions, which include the
effects of past and present actions at the plants.
Contents of Chapter 3
• Description of Nuclear Power Plant Facilities and Operations (Section 3.1)
• Land Use and Visual Resources (Section 3.2)
• Meteorology, Air Quality, and Noise (Section 3.3)
• Geologic Environment (Section 3.4)
• Water Resources (Section 3.5)
• Ecological Resources (Section 3.6)
• Historic and Cultural Resources (Section 3.7)
• Socioeconomics (Section 3.8)
• Human Health (Section 3.9)
• Environmental Justice (Section 3.10)
• Waste Management and Pollution Prevention (Section 3.11)
• Greenhouse Gas Emissions and Climate Change (Section 3.12)

3.1
3.1.1

Description of Nuclear Power Plant Facilities and Operations
External Appearance and Settings

Nuclear power plants contain a number of buildings or structures. Among them, depending on
the nuclear plant, are containment or reactor buildings, turbine buildings, auxiliary buildings,
vent stacks, meteorological towers, and cooling systems, particularly cooling towers. A plant site
layout also includes large parking areas, security fencing, switchyards, water intake and
discharge facilities, and transmission lines (see Section 3.1.7). While reactor, turbine, and
auxiliary buildings are often clad or painted in colors that are intended to reduce or mitigate their
visual presence, the heights of many of the structures, coupled with red and/or white safety
lights, make nuclear plants visible from many directions. Typical heights of nuclear plant
facilities are as follows: reactor buildings are 300 ft (90 m), turbine buildings are 100 ft (30 m),

3-1

NUREG-1437, Revision 2

Affected Environment
stacks are 300 ft (90 m), meteorological towers are 200 ft (60 m), natural draft cooling towers
are higher than 500 ft (150 m), and mechanical draft cooling towers are 100 ft (30 m) tall. In
addition, condensation from cooling towers is generally visible for many miles. Transmission line
towers are between 70 ft (20 m) and 170 ft (50 m) in height, depending on their voltage.
There are two types of power reactors, within the current scope of this revised LR GEIS, and
currently operating in the United States—boiling water reactors (BWRs) and pressurized water
reactors (PWRs). All nuclear power plant sites are generally similar in terms of the types of
facilities they contain. All plant sites contain a nuclear steam supply system. In addition, there
are a number of common structures necessary for plant operation. These structures and
facilities include, but are not limited to, the containment or reactor building, fuel building, turbine
building, auxiliary buildings, diesel generator building, pump houses, cooling towers, radioactive
waste facilities, ventilation stacks, switchyards and transmission lines, and independent spent
fuel storage installations (ISFSIs). However, the layout of buildings and structures varies
considerably among the sites. For example, control rooms may be located in the auxiliary
building, in a separate control building, or in a radwaste and control building. Section G.1.1.1 in
Appendix G describes typical structures located on most nuclear power plant sites.
Nuclear power plant site areas range from 391 acres (ac) (158 hectares [ha]) to 14,000 ac
(5,700 ha), with most sites encompassing 700 to 2,500 ac (283 to 1,000 ha). Larger land use
areas are associated with plant cooling systems that include reservoirs, artificial lakes, and
buffer areas.
Nuclear power plant sites are located in a range of political jurisdictions, including towns,
townships, service districts, counties, parishes, and States. The population density within a
50 mi (80 km) radius of nuclear plants varies. Within the 50 mi (80 km) radius, Federal, State,
and Tribal lands are present to various extents. Typically, inland nuclear power plant sites and
their surrounding areas consist of flat to rolling countryside in wooded or agricultural areas.
Coastal and Great Lakes nuclear power plant sites include riparian, wetland, beach, and other
shoreline habitats. See Appendix C for summary descriptions of the characteristics of nuclear
power plant sites and their surroundings.
3.1.2

Nuclear Reactor Systems

In the United States, all of the currently operating reactors used for commercial power
generation are conventional (thermal) light water reactors (LWRs) that use water as a
moderator and coolant. The two types of LWRs are PWRs and BWRs. Of the 92 operating
LWRs, 61 are PWRs and 31 are BWRs (Figure 3.1-1 and Table 3.1-1). They are located at
54 nuclear power plant sites (two plants are collocated, Hope Creek Generating Station
[Hope Creek] and Salem Nuclear Generating Station [Salem] in New Jersey) in 28 States.1
Some of the reactors have sought and received power uprates since initial licensing, which
allow these plants to operate at higher licensed power levels. Power uprates are a separate
licensing action from license renewal and require separate U.S. Nuclear Regulatory
Commission (NRC) review and approval. For the reactors that have been authorized to increase
their power level, power uprate information is incorporated into Table 3.1-1. Additional reactors
may seek power uprates in the future.
1

This count does not include Vogtle Units 3 and 4, in Waynesboro, Georgia, which are new, large light
water reactors that commenced commercial operations in July 2023 and April 2024, respectively. The
scope of this revised LR GEIS is limited to nuclear power plants for which an operating license,
construction permit, or combined license was issued as of June 30, 1995.

NUREG-1437, Revision 2

3-2

3-3
Affected Environment

NUREG-1437, Revision 2

Figure 3.1-1 Operating Commercial Nuclear Power Plants in the United States

Nuclear Power Plant

Characteristics of Operating U.S. Commercial Nuclear Power Plants(a)
Year
Operating
License
Unit Granted

Year
License
Expires

Net
Capacity
(MWe)

Design
Condenser Total Site
Reactor Flow Rate
Area
Type
(103 gpm)
(acres)

Nearest City

3-4

Arkansas Nuclear One
Arkansas Nuclear One

1
2

1974
1978

2034
2038

833
985

PWR
PWR

762
422

1,164

Little Rock, AR

Beaver Valley Power Station
Beaver Valley Power Station

1
2

1976
1987

2036
2047

892
901

PWR
PWR

480
480

453

Braidwood Station
Braidwood Station

1
2

1987
1988

2046
2047

1,183
1,154

PWR
PWR

730
730

4,457

Browns Ferry Nuclear Plant
Browns Ferry Nuclear Plant

1
2

1973
1974

2033
2034

1,256
1,259

BWR
BWR

734
734

840

Browns Ferry Nuclear Plant

3

1976

2036

1,260

BWR

734

Brunswick Steam Electric Plant
Brunswick Steam Electric Plant

1
2

1976
1974

2036
2034

938
932

BWR
BWR

675
675

1,200

Byron Station
Byron Station

1
2

1985
1987

2044
2046

1,182
1,154

PWR
PWR

632
632

1,398

Callaway Plant
Calvert Cliffs Nuclear Power Plant
Calvert Cliffs Nuclear Power Plant

1
1
2

1984
1974
1976

2044
2034
2036

1,190
866
842

PWR
PWR
PWR

530
1,200
1,200

5,228
2,108

Catawba Nuclear Station
Catawba Nuclear Station

1
2

1985
1986

2043
2043

1,160
1,150

PWR
PWR

660
660

391

Clinton Power Station
Columbia Generating Station
Comanche Peak Nuclear Power Plant
Comanche Peak Nuclear Power Plant

1
1
1
2

1987
1984
1989
1993

2027
2043
2030
2033

1,065
1,163
1,205
1,195

BWR
BWR
PWR
PWR

569
550
1,030
1,030

14,000
1,089
7,669

Cooper Nuclear Station
Donald C. Cook Nuclear Plant
Donald C. Cook Nuclear Plant

1
1
2

1974
1974
1977

2034
2034
2037

770
1,009
1,060

BWR
PWR
PWR

631
800
800

1,251
650

-

-

Davis-Besse Nuclear Power Station
Diablo Canyon Power Plant(b)
Diablo Canyon Power Plant(b)

1
1
2

1977
1984
1985

2037
2024
2025

894
1,122
1,118

PWR
PWR
PWR

480
863
863

733
750
-

Toledo, OH
Santa Barbara, CA

Dresden Nuclear Power Station
Dresden Nuclear Power Station

2
3

1969
1971

2029
2031

902
895

BWR
BWR

940
940

2,500
-

-

Pittsburgh, PA

-

-

5,033,013
-

Huntsville, AL

-

Wilmington, NC

-

Rockford, IL

-

Columbia, MO
Washington, D.C.

-

Charlotte, NC

-

Decatur, IL
Spokane, WA
Fort Worth, TX

-

312,591
3,146,489
-

Joliet, IL

-

2020
Population
within
50 mi

Lincoln, NE
South Bend, IN

1,081,319
548,758
1,284,960
585,372
3,962,475
3,034,933
815,617
517,245
2,077,599
153,581
1,265,894
-

-

1,812,385
499,952
-

-

7,525,651
-

Joliet, IL

Affected Environment

NUREG-1437, Revision 2

Table 3.1-1

Nuclear Power Plant
Joseph M. Farley Nuclear Plant
Joseph M. Farley Nuclear Plant

Year
Operating
License
Unit Granted
1
1977
2
1981

Year
License
Expires
2037
2041

Net
Capacity
(MWe)
874
877

Design
Condenser Total Site
Reactor Flow Rate
Area
Type
(103 gpm)
(acres)
Nearest City
PWR
635
1,850
Columbus, GA
PWR
635
-

3-5

2
1
1
1
1
1
2

1985
1974
1969
1984
1987
1974
1978

2045
2034
2029
2044
2046
2034
2038

1,141
848
581
1,401
964
876
883

BWR
BWR
PWR
BWR
PWR
BWR
BWR

836
353
340
572
483
556
556

1,120
702
488
2,100
10,744
2,240
-

Detroit, MI
Syracuse, NY
Rochester, NY
Jackson, MS
Raleigh, NC
Savannah, GA

Hope Creek Generating Station
LaSalle County Station
LaSalle County Station

1
1
2

1986
1982
1984

2046
2042
2043

1,172
1,131
1,134

BWR
BWR
BWR

552
645
645

740
3,060
-

Wilmington, DE
Joliet, IL

Limerick Generating Station
Limerick Generating Station

1
2

1985
1990

2049
2049

1,120
1,122

BWR
BWR

450
450

595
-

Reading, PA

McGuire Nuclear Station
McGuire Nuclear Station

1
2

1981
1983

2041
2043

1,159
1,158

PWR
PWR

675
675

577
-

Charlotte, NC

Millstone Power Station
Millstone Power Station

2
3

1975
1986

2035
2045

853
1,220

PWR
PWR

523
907

500
-

New Haven, CT

Monticello Nuclear Generating Plant
Nine Mile Point Nuclear Station
Nine Mile Point Nuclear Station

1
1
2

1970
1968
1987

2030
2029
2046

617
621
1,292

BWR
BWR
BWR

292
290
580

1,250
900
-

Minneapolis, MN
Syracuse, NY

North Anna Power Station
North Anna Power Station

1
2

1978
1980

2038
2040

948
944

PWR
PWR

950
950

1,043
-

Richmond, VA

Oconee Nuclear Station
Oconee Nuclear Station

1
2

1973
1973

2033
2033

847
848

PWR
PWR

680
680

510
-

Greenville, SC

Oconee Nuclear Station

3

1974

2034

859

PWR

680

-

Palisades Nuclear
Palo Verde Nuclear Generating Station
Palo Verde Nuclear Generating Station

1
1
2

1972
1985
1986

2031
2045
2046

769
1,211
1,314

PWR
PWR
PWR

98
560
560

432
4,050
-

Palo Verde Nuclear Generating Station

3

1987

2047

1,312

PWR

560

-

Peach Bottom Atomic Power Station

2

1973

2053

1,265

BWR

750

620

Plant(c)

-

-

Kalamazoo, MI
Phoenix, AZ

Lancaster, PA

4,908,826
932,913
1,299,149
323,744
3,041,733
464,024
5,946,917
1,948,438
8,594,665
3,351,808
3,071,351
3,347,158
927,862
2,237,934
1,577,801
1,441,106
2,350,442
6,005,101

Affected Environment

NUREG-1437, Revision 2

Enrico Fermi Atomic Power Plant
James A. FitzPatrick Nuclear Power Plant
R.E. Ginna Nuclear Power Plant
Grand Gulf Nuclear Station
Shearon Harris Nuclear Power Plant
Edwin I. Hatch Nuclear Plant
Edwin I. Hatch Nuclear Plant

2020
Population
within
50 mi
425,394
-

Year
License
Expires
2054

Net
Capacity
(MWe)
1,285

Design
Condenser Total Site
Reactor Flow Rate
Area
Type
(103 gpm)
(acres)
BWR
750
-

Nearest City

-

3-6

Perry Nuclear Power Plant
Point Beach Nuclear Plant
Point Beach Nuclear Plant

1
1
2

1986
1970
1972

2026
2030
2033

1,261
598
603

BWR
PWR
PWR

545
350
350

1,100
1,260
-

Euclid, OH
Green Bay, WI

Prairie Island Nuclear Generating Plant
Prairie Island Nuclear Generating Plant

1
2

1973
1974

2033
2034

521
519

PWR
PWR

294
294

560
-

Minneapolis, MN

Quad Cities Nuclear Power Station
Quad Cities Nuclear Power Station

1
2

1972
1972

2032
2032

908
911

BWR
BWR

485
485

817
-

Davenport, IA

River Bend Station
H.B. Robinson Steam Electric Plant
St. Lucie Nuclear Plant

1
2
1

1985
1970
1976

2045
2030
2036

968
759
981

BWR
PWR
PWR

508
454
484

3,300
6,020
1,130

St. Lucie Nuclear Plant

2

1983

2043

987

PWR

484

-

Salem Nuclear Generating Station
Salem Nuclear Generating Station

1
2

1976
1981

2036
2040

1,174
1,130

PWR
PWR

1,100
1,100

700
-

Wilmington, DE

Seabrook Station
Sequoyah Nuclear Plant
Sequoyah Nuclear Plant

1
1
2

1990
1980
1981

2050
2040
2041

1,295
1,152
1,126

PWR
PWR
PWR

399
522
522

889
525
-

Lawrence, MA
Chattanooga, TN

South Texas Project Electric Generating Station
South Texas Project Electric Generating Station

1
2

1988
1989

2047
2048

1,280
1,280

PWR
PWR

907
907

12,350
-

Galveston, TX

Virgil C. Summer Nuclear Station
Surry Power Station
Surry Power Station
Susquehanna Steam Electric Station
Susquehanna Steam Electric Station

1
1
2
1
2

1982
1972
1973
1982
1984

2042
2052
2053
2042
2044

971
838
838
1,247
1,247

PWR
PWR
PWR
BWR
BWR

507
840
840
484
484

2,245
840
840
1,173
-

Columbia, SC
Newport News, VA

Turkey Point Nuclear Plant
Turkey Point Nuclear Plant
Vogtle Electric Generating Plant
Vogtle Electric Generating Plant

3
4
1
2

1972
1973
1987
1989

2052
2053
2047
2049

837
861
1,150
1,152

PWR
PWR
PWR
PWR

650
650
510
510

2,400
3,169
-

Miami, FL
Augusta, GA

Waterford Steam Electric Station
Watts Bar Nuclear Plant

3
1

1985
1996

2044
2035

1,250
1,123

PWR
PWR

975
410

3,000
1,170

New Orleans, LA
Chattanooga, TN

Baton Rouge, LA
Columbia, SC
West Palm Beach,
FL

-

-

Wilkes-Barre, PA

-

-

2020
Population
within
50 mi
2,299,476
826,680
3,309,059
655,699
1,037,151
922,132
1,456,749
5,873,042
4,693,723
1,172,704
268,364
1,289,146
2,462,820
1,829,035
3,813,589
789,654
2,171,180
1,312,700

Affected Environment

NUREG-1437, Revision 2

Nuclear Power Plant
Peach Bottom Atomic Power Station

Year
Operating
License
Unit Granted
3
1974

Nuclear Power Plant
Watts Bar Nuclear Plant

Year
Operating
License
Unit Granted
2
2015

Year
License
Expires
2055

Net
Capacity
(MWe)
1,122

Design
Condenser Total Site
Reactor Flow Rate
Area
Type
(103 gpm)
(acres)
PWR
410
-

Nearest City

2020
Population
within
50 mi

-

-

3-7

Affected Environment

NUREG-1437, Revision 2

Wolf Creek Generating Station
1
1985
2045
1,166
PWR
500
9,818
Topeka, KS
173,018
BWR = boiling water reactor, gpm = gallon(s) per minute; mi = mile(s); MWe = megawatt(s)-electric; PWR = pressurized water reactor.
(a) The 2013 LR GEIS (NRC 2013a) included a number of nuclear power plants that are not being considered for license renewal and are not included in this
table. They include the following plants:
•
Bellefonte: Construction permits issued in 1974. Units 1 & 2 were never finished and mothballed in 1988. Currently under the NRC’s Deferred Policy.
•
Big Rock Point: Shutdown in 1997; decommissioning completed in August 2006. Stored spent fuel is still onsite.
•
Crystal River Nuclear Power Plant (Crystal River) Unit 3: Shutdown in 2013. Decommissioning completion scheduled for 2026–2030.
•
Duane Arnold Energy Center (Duane Arnold): Shutdown in 2020. Decommissioning completion scheduled for 2080.
•
Fort Calhoun Station (Fort Calhoun): Shutdown in 2016. Decommissioning completion scheduled for 2026.
•
Haddam (Connecticut Yankee): Shutdown in 1996; decommissioned in 2004. Stored spent fuel is still onsite.
•
Indian Point Energy Center (Indian Point) Unit 2: Shutdown in 2020; Unit 3: Shutdown in 2021. Decommissioning completion scheduled for 2026 to 2033.
•
Kewanee: Shutdown in 2013. Decommissioning completion scheduled for 2073.
•
Maine Yankee: Closed in 1997; decommissioned completed in 2005. Stored spent fuel is still onsite.
•
Millstone Power Station (Millstone), Unit 1: Shutdown in 1995; Decommissioning completion scheduled for 2056.
•
Oyster Creek Nuclear Generating Station (Oyster Creek): Shutdown in 2018. Decommissioning completion scheduled for 2025.
•
Pilgrim Nuclear Power Station (Pilgrim): Shutdown in 2019. Decommissioning completion scheduled for 2027.
•
Rancho Seco: Shutdown in 1989; decommissioning completed and licensed terminated in 2018. Stored spent fuel is still onsite.
•
San Onofre Nuclear Generating Station (San Onofre): Unit 1: Shutdown in 1992; Units 2 and 3: Shutdown in 2013. Decommissioning completion
scheduled for 2030–2031.
•
Shoreham: Fully decommissioned in 1994; it never produced power.
•
Three Mile Island Unit 1: Shutdown in 2019. Decommissioning completion scheduled for 2079. Unit 2: Shutdown in 1979. Decommissioning completion
scheduled for 2037.
•
Trojan: Closed in 1992; decommissioning completed in 2006. Stored spent fuel is still onsite.
•
Vermont Yankee Nuclear Power Station (Vermont Yankee): Shutdown in 2014. Decommissioning completion scheduled for 2026–2030.
•
Yankee Rowe: Shutdown in 1992; decommissioning completed in 2006. Stored spent fuel is still onsite.
•
Zion: Shutdown in 1998, decontamination and dismantlement began in 2011 and is scheduled to be completed by the end of 2022.
(b) Diablo Canyon Power Plant (Diablo Canyon): On March 2, 2023, the NRC granted Pacific Gas and Electric Company an exemption from 10 CFR 2.109(b),
provided a sufficient license renewal application is submitted by December 31, 2023, and the NRC staff finds it acceptable for docketing, which would render
the existing operating licenses effective until the NRC has made a final determination on the application (NRC 2023a). On November 7, 2023, the licensee
submitted a license renewal application for Diablo Canyon. On December 19, 2023, the NRC issued a notice in the Federal Register that it found the
application acceptable for docketing as well as an opportunity to request a hearing and to petition for leave to intervene.
(c) Palisades Nuclear Plant (Palisades): Shutdown in May 2022; however, shortly thereafter the plant operator began exploring options to resume operations. As
of the time of this update, the status for the plant has yet to be determined. As a result, the plant has been retained in this table for the purposes of this
LR GEIS update.
No entry has been denoted by “-”.
Sources: Appendix C, NRC 2018f, NRC 2021r; Pacific Northwest National Laboratory calculations based on 2020 decennial census data.

Affected Environment
The nuclear fuel used in all LWRs is uranium enriched to 2 to 5 percent in the uranium-235
isotope. The fuel is in the form of cylindrical uranium dioxide pellets, which are approximately
0.4 in. (1 centimeter [cm]) in diameter and 0.4 to 0.6 in. (1 to 1.5 cm) in height. The fuel pellets
are stacked and sealed inside a hollow cylindrical zirconium alloy fuel rod. The fuel rods, also
called fuel pins or fuel elements, are approximately 12 ft (3.6 m) long. They are bundled into fuel
assemblies that generally consist of matrices of 15 × 15 or 17 × 17 rods for PWRs and 8 × 8 or
10 × 10 rods for BWRs. When new fuel is loaded into the reactors or spent fuel is removed from
reactors, the fuel is handled as intact assemblies. Similarly, when spent fuel is stored onsite
awaiting shipment offsite, the fuel assemblies remain intact.
Fission reactions that occur inside the fuel, primarily by the uranium-235 isotope, are the source
of thermal energy in a nuclear reactor. This energy is transferred to the coolant, which is
ordinary water, circulating in the primary coolant system in LWRs. The vessel, which encloses
the reactor, is part of the primary coolant system.
In PWRs, water is heated to a high temperature under pressure inside the reactor vessel
(Figure 3.1-2). The water flows in the primary circulation loop to the steam generator. Within the
steam generator, water in the secondary circulation loop is converted to steam that drives the
turbines. The turbines turn the generator to produce electricity. The steam leaving the turbines
is condensed by water in the tertiary loop and returned to the steam generator. The tertiary loop
water flows to cooling towers where it is cooled by evaporation, or it is discharged directly to a
body of water, such as a river, lake, or other heat sink (see Section 3.1.3). The tertiary loop is
open to the atmosphere, but the primary and secondary cooling loops are not.

Figure 3.1-2 Pressurized Water Reactor. Adapted from NRC 2002c.
BWRs generate high pressure steam directly within the reactor vessel (Figure 3.1-3). The steam
passes through moisture separators and steam dryers and then flows to the turbines. Because it
generates steam directly in the reactor vessel, the power generation system contains only two
heat transfer loops. The primary loop transports the steam from the reactor vessel directly to the
turbines, which generate electricity. The secondary coolant loop removes excess heat from the
primary loop in the condenser. From the condenser, the primary condensate proceeds into the
feedwater stage, and the secondary coolant loop removes the excess heat and discharges it to
the receiving waterbody. As is the case for PWRs, the coolant water from the condenser is
pumped to cooling towers or it is discharged directly to a waterbody.

NUREG-1437, Revision 2

3-8

Affected Environment

Figure 3.1-3 Boiling Water Reactor. Adapted from NRC 2002c.
3.1.3

Cooling Water Systems

In LWR designs, water is used to remove excess heat generated in reactor systems. The
volume of water required and rate of flow is a function of several factors, including the licensed
thermal power level of the reactor and the increase in cooling water temperature from the intake
to the discharge. In general, larger nuclear power plants (i.e., more reactor units and/or higher
licensed power levels) generate more waste heat and require more water for cooling.
Table 3.1-2 through Table 3.1-4 describe the configurations of the cooling systems used at
existing nuclear power plant sites. There are two major types of cooling systems: once-through
and closed-cycle (also known as recirculating). Once-through cooling systems withdraw water
for condenser cooling from a nearby waterbody, such as a lake or river, circulate it through the
condenser tubes, and return that water as heated effluent to the same waterbody
(Figure 3.1-4a).
Average water withdrawal for nuclear power plants using once-through cooling is about
39,000 gal/MWh (148 m3/MWh) of electricity generated (USGS 2019b). Using the dataset
described by Marston et al. (2018) for operating nuclear power plants, most plants using oncethrough cooling withdraw between 28,000 and 52,000 gal/MWh (106 to 197 m3/MWh) of water.
In a once-through cooling system, waste heat is dissipated to the atmosphere mainly through
evaporation, mixing with ambient water from the source waterbody, and, to a much smaller
extent, by conduction, convection, and thermal radiation loss. Average consumptive water use
for nuclear power plants using once-through cooling is about 400 gal/MWh (1.51 m3/MWh)
(USGS 2019b), with most plants estimated to consume between 290 and 570 gal/MWh (1.1 to
2.2 m3/MWh) of water during electricity generation (based on the dataset described by Marston
et al. [2018]).

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NUREG-1437, Revision 2

Affected Environment
Table 3.1-2

Cooling Water System Source – Coastal or Estuarine Environment

Nuclear Power Plant

State

Cooling System

Cooling Water Source

Brunswick

North Carolina

Once-through

Cape Fear River

Calvert Cliffs

Maryland

Once-through

Chesapeake Bay

Diablo Canyon

California

Once-through

Pacific Ocean

Hope Creek

New Jersey

Natural draft cooling tower

Delaware River

Millstone

Connecticut

Once-through

Long Island Sound

Salem

New Jersey

Once-through

Delaware River

Seabrook

New Hampshire

Once-through

Gulf of Maine

South Texas

Texas

Cooling pond

Colorado River

St. Lucie

Florida

Once-through

Atlantic Ocean

Surry

Virginia

Once-through

James River

Turkey Point

Florida

Cooling canal

Biscayne Bay; Upper
Floridan Aquifer
(supplemental source)

Table 3.1-3

Cooling Water System Source – Great Lakes Environment

Nuclear Power Plant

State

Cooling System

Cooling Water Source

D.C. Cook

Michigan

Once-through

Lake Michigan

Davis-Besse

Ohio

Natural draft cooling tower

Lake Erie

Fermi

Michigan

Natural draft cooling towers

Lake Erie

FitzPatrick

New York

Once-through

Lake Ontario

Ginna

New York

Once-through

Lake Ontario

Nine Mile Point

New York

Unit 1: Once-through
Unit 2: Natural draft cooling
tower

Lake Ontario

Palisades(a)

Michigan

Mechanical draft cooling towers Lake Michigan

Perry

Ohio

Natural draft cooling tower

Lake Erie

Point Beach

Wisconsin

Once-through

Lake Michigan

(a)

Palisades shutdown in May 2022 but has been retained in this LR GEIS update.

Table 3.1-4

Cooling Water System Source – Freshwater Riverine or Impoundment
Environment

Nuclear Power Plant

State

Cooling System

Cooling Water
Source

Arkansas

Arkansas

Unit 1: once-through
Unit 2: natural draft cooling
tower

Lake Dardanelle

Beaver Valley

Pennsylvania

Natural draft cooling towers

Ohio River

Braidwood

Illinois

Cooling pond

Kankakee River

NUREG-1437, Revision 2

3-10

Affected Environment

Nuclear Power Plant

State

Cooling Water
Source

Cooling System

Browns Ferry

Alabama

Once-through (helper towers)

Wheeler Reservoir

Byron

Illinois

Natural draft cooling towers

Rock River

Callaway

Missouri

Natural draft cooling tower

Missouri River

Catawba

South Carolina

Mechanical draft cooling
towers

Lake Wylie

Clinton

Illinois

Once-through (cooling pond)

Salt Creek

Columbia

Washington

Mechanical draft cooling
towers

Columbia River

Comanche Peak

Texas

Once-through

Comanche Peak
Reservoir

Cooper

Nebraska

Once-through

Missouri River

Dresden

Illinois

Cooling pond and optional
mechanical draft cooling tower
or once-through including
residence time in pond and
optional cooling towers

Kankakee River

Farley

Alabama

Mechanical draft cooling
towers

Chattahoochee River

Grand Gulf

Mississippi

Natural draft cooling tower

Mississippi River

H.B. Robinson

South Carolina

Once-through (cooling pond)

Lake Robinson

Harris

North Carolina

Natural draft cooling towers

Harris Reservoir

Hatch

Georgia

Mechanical draft cooling
towers

Altamaha River

LaSalle

Illinois

Cooling pond

Illinois River

Limerick

Pennsylvania

Natural draft cooling towers

Schuylkill River

McGuire

North Carolina

Once-through

Lake Norman

Monticello

Minnesota

Once-through and mechanical
draft cooling towers

Mississippi River

North Anna

Virginia

Once-through

Lake Anna

Oconee

South Carolina

Once-through

Lake Keowee

Palo Verde

Arizona

Mechanical draft cooling
towers

Phoenix Wastewater
Treatment Plant
Effluent

Peach Bottom

Pennsylvania

Unit 2: Once-through
Unit 3: Once-through and
mechanical draft cooling
towers

Conowingo Pond

Prairie Island

Minnesota

Once-through and mechanical
draft cooling towers

Mississippi River

Quad Cities

Illinois

Once-through

Mississippi River

River Bend

Louisiana

Mechanical draft cooling
towers

Mississippi River

3-11

NUREG-1437, Revision 2

Affected Environment

Nuclear Power Plant

State

Cooling System

Cooling Water
Source

Sequoyah

Tennessee

Once-through and natural draft
cooling towers

Chickamauga Lake

Summer

South Carolina

Cooling pond

Monticello Reservoir

Susquehanna

Pennsylvania

Natural draft cooling towers

Susquehanna River

Vogtle

Georgia

Natural draft cooling towers

Savannah River

Waterford

Louisiana

Once-through

Mississippi River

Watts Bar

Tennessee

Natural draft cooling towers

Chickamauga Lake

Wolf Creek

Kansas

Cooling pond

Coffey County Lake

Closed-cycle cooling systems typically use recirculated water from cooling towers to cool the
condenser. Some nuclear power plants use cooling ponds, lakes, reservoirs, or canals
(Figure 3.1-4b) that often function as closed-cycle systems. The average water withdrawal for
nuclear power plants using closed-cycle cooling is 480 gal/MWh (1.82 m3/MWh) for cooling
ponds or lakes and 700 gal/MWh (2.65 m3/MWh) for cooling towers (USGS 2019b). Because
the predominant cooling mechanism associated with closed-cycle systems is evaporation, much
of the water used for cooling is consumed and is not returned to the water source. The average
consumptive water use for nuclear power plants using cooling towers is 500 gal/MWh
(1.9 m3/MWh) (USGS 2019b). Based on the dataset described by Marston et al. (2018),
consumptive water use for most nuclear power plants using closed-cycle cooling ranges
between 450 and 750 gal/MWh (1.7 to 2.8 m3/MWh). Makeup water to account for these losses
is typically withdrawn from a surface waterbody near the site, and blowdown (water that is
periodically rinsed from the cooling system to remove impurities and sediment that may degrade
performance) is typically released to the same surface waterbody.
Several nuclear plants use hybrid cooling systems that may be used in different configurations
at different times of the year (Figure 3.1-4c). For instance, some once-through cooling system
plants also operate cooling towers (sometimes referred to as “helper towers”) seasonally to
reduce thermal load to the receiving waterbody, reduce entrainment during peak spawning
periods, or reduce consumptive water use during periods of low river flow. The Peach Bottom
Atomic Power Station (Peach Bottom) (NRC 2003b, NRC 2020g) has helper mechanical draft
cooling towers that can process up to 60 percent of the plant’s heated effluent, while the
remaining effluent is discharged as part of the once-through system. The Monticello Nuclear
Generating Plant (Monticello) (NRC 2006c) uses once-through cooling in the winter but has
mechanical draft cooling towers for closed-cycle cooling in the summer. The Dresden Nuclear
Power Station (Dresden) (NRC 2004c) is similar in that it relies on a cooling pond system in the
fall, winter, and spring, but in the summer, the plant operates as a once-through system that
uses the cooling pond and helper mechanical draft cooling towers to reduce effluent
temperatures before releasing the water to the Kankakee River (see Table 3.1-4). The
Browns Ferry Nuclear Plant (Browns Ferry) (NRC 2005b) uses mechanical draft cooling towers
in helper mode in accordance with conditions in its National Pollutant Discharge Elimination
System (NPDES) permit to limit thermal impacts on Wheeler Reservoir.

NUREG-1437, Revision 2

3-12

Affected Environment

Figure 3.1-4 Schematic Diagrams of Nuclear Power Plant Cooling Systems.
Source: NRC 2013a.
All existing sites with two or three reactor units use the same cooling system for all units, except
for two sites: the Arkansas Nuclear One (Arkansas) plant in Arkansas and Nine Mile Point
Nuclear Station (Nine Mile Point) in New York. These two sites use once-through cooling for
one unit and closed-cycle cooling for the other. The configuration of each nuclear power plant
intake and discharge structure varies to accommodate the source waterbody and to minimize
impacts on the hydrologic environment and aquatic ecosystem. Intake structures generally are
located along the shoreline of the source waterbody. Most are equipped with devices that
reduce impingement and entrainment of fish and other aquatic organisms. Some include fish
return systems that return impinged organisms to the source waterbody. Discharge structures
usually consist of pipes or canals that terminate in discharge jets or diffusers that promote rapid
mixing of the effluent with the receiving body of water. Discharge of condenser cooling water
(once-through systems) and blowdown water (closed-cycle systems) containing biocides and
other chemicals used for corrosion control and other water treatment purposes are authorized

3-13

NUREG-1437, Revision 2

Affected Environment
by the U.S. Environmental Protection Agency (EPA), or authorized States and Tribes, under
NPDES permits, which establish limits, as necessary, based on flow rates, chemical
concentrations, and thermal criteria.
In addition to heat removal, nuclear power plants require cooling water for service water and
auxiliary cooling water systems. Service water is special-purpose water that may not be treated
for use. The auxiliary cooling water system typically includes the emergency core cooling
system, the containment spray and cooling system, the emergency feedwater system, the
component cooling water system, and the spent fuel pool water system. The volume of water
required for these systems is usually less than 15 percent of the volume required for condenser
cooling in once-through cooling systems. In closed-cycle cooling systems, the additional water
needed for service water and auxiliary purposes is usually less than 5 percent of that needed for
condenser cooling (NRC 1996).
Some nuclear power plants also use groundwater as a source for service, makeup, or potable
water. The Grand Gulf Nuclear Station (Grand Gulf) uses groundwater as a source of makeup
water to the condenser cooling system. This plant employs a radial collector well system (i.e.,
also known as Ranney® wells) to draw groundwater from the Mississippi River Alluvial aquifer
(NRC 2014e). The Turkey Point Nuclear Plant (Turkey Point) also draws groundwater from the
Upper Floridan Aquifer as a supplemental source of makeup water to the cooling canal system
(CCS). These withdrawals primarily address salinity levels in the system and are part of a
State-mandated mitigation program to restore salinity to a level similar to that of nearby surface
waters (i.e., Biscayne Bay) (NRC 2019c).
3.1.4

Radioactive Waste Management Systems

During the fission process, a large inventory of radioactive fission products builds up within the
fuel. Virtually all of the fission products are contained within the fuel pellets. The fuel pellets are
enclosed in hollow metal rods (cladding), which are hermetically sealed to further prevent the
release of fission products. However, a small fraction of the fission products escape from the
fuel rods and contaminate the reactor coolant. The primary system coolant also has radioactive
contaminants as a result of neutron activation. The radioactivity in the reactor coolant is the
source of liquid, gaseous, and most of the solid radioactive wastes at LWRs. The following
sections describe the basic design and operation of PWR and BWR radioactive waste treatment
systems.
3.1.4.1

Liquid Radioactive Waste

Radionuclide contaminants in the primary coolant are the source of liquid radioactive waste in
LWRs. The specific sources of these wastes, their associated modes of collection and
treatment, and the types and quantities of liquid radioactive wastes released to the environment
are similar in many respects in BWRs and PWRs. Accordingly, the following discussion applies
to both BWRs and PWRs; distinctions are made only when important differences exist.
Liquid wastes resulting from LWR operation may be placed into the following categories: clean
wastes, dirty wastes, detergent wastes, turbine building floor-drain water, and steam generator
blowdown (PWRs only). Clean wastes include all liquid wastes with normally low conductivity
and variable radioactivity. They consist of reactor-grade water, which is amenable to processing
for reuse as reactor coolant makeup water. Clean wastes are collected from equipment leaks
and drains, certain valve and pump seal leaks, and other aerated leakage sources. Dirty wastes
include all liquid wastes with moderate chemical (ionic) conductivity and variable radioactivity

NUREG-1437, Revision 2

3-14

Affected Environment
that, after processing, may be used as reactor coolant makeup water. Dirty wastes consist
of liquid wastes collected in the containment building sump, auxiliary building sumps and
drains, laboratory drains, sample station drains, and other floor drains. Detergent wastes
consist principally of laundry wastes and personnel and equipment decontamination wastes
and normally have low radioactivity. Turbine building floor-drain wastes usually have high
conductivity and a low radionuclide content. In PWRs, steam generator blowdown can
have relatively high concentrations of radionuclides, depending on the amount of
primary-to-secondary leakage. After processing, the water may be reused or discharged.
Each of these sources of liquid wastes receives varying degrees and types of treatment before
being stored for reuse or discharged to the environment in accordance with applicable
regulatory requirements and permit provisions (e.g., NPDES permit). The extent and types of
treatment depend on the chemical content of the waste; to increase the efficiency of waste
processing, wastes with similar characteristics are batched before treatment.
Controls for limiting the release of radiological liquid effluents at each nuclear power plant are
described in the facility’s Offsite Dose Calculation Manual (ODCM). Controls are based on
(1) concentrations of radioactive materials in liquid effluents and (2) dose to a member of the
public. Concentrations of radioactive material that are allowed to be released in liquid effluents
to unrestricted areas are limited to the concentration specified in Title 10 Code of Federal
Regulations (10 CFR) Part 20, Appendix B, Table 2.
The degree and effectiveness of processing, storing, and recycling of liquid radioactive waste
has steadily increased among operating plants. For example, extensive recycling of steam
generator blowdown in PWRs is now the typical mode of operation, and secondary side
wastewater is routinely treated. In addition, the plant systems that process wastes are often
augmented by commercial mobile processing systems. As a result, radionuclide releases in
liquid effluent from LWRs have generally declined for most plants or remained the same over
time.
3.1.4.2

Gaseous Radioactive Waste

The gaseous waste management system collects fission products, mainly noble gases, which
accumulate in the primary coolant. A small portion of the primary coolant flow is continually
diverted to the primary coolant purification, volume, and chemical control system to remove
contaminants and adjust the coolant chemistry and volume. During this process,
noncondensable gases are stripped and routed to the gaseous waste management system,
which consists of a series of gas storage tanks. The storage tanks allow the short-half-life
radioactive gases to decay, leaving only relatively small quantities of long-half-life radionuclides
to be released to the atmosphere. Some LWRs may use charcoal delay systems rather than
gas storage tanks.
For BWRs, the sources of routine radioactive gaseous emissions to the atmosphere are the air
ejector, which removes noncondensable gases from the main turbine condenser to improve
power conversion efficiency, and gaseous and vapor leakages, which, after monitoring and
filtering, are discharged to the atmosphere via the building ventilation systems.
PWRs have three primary sources of gaseous radioactive emissions: (1) discharges from the
gaseous waste management system; (2) discharges associated with the exhaust of
noncondensable gases at the main condenser if a primary-to-secondary system leak exists; and
(3) radioactive gaseous discharges from the building ventilation exhaust, including the reactor
building, reactor auxiliary building, and fuel-handling building.
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NUREG-1437, Revision 2

Affected Environment
The quantities of gaseous effluents released from operating plants are controlled by the
administrative limits that are defined in the ODCM, which is specific for each nuclear power
plant. Controls are based on (1) the rate at which the gaseous effluent is released and (2) dose
to a member of the public. The limits in the ODCM are designed to provide reasonable
assurance that radioactive materials discharged in gaseous effluents are not in excess of the
limits specified in 10 CFR Part 20, Appendix B, thereby limiting the exposure of a member of the
public in an unrestricted area.
3.1.4.3

Solid Radioactive Waste

Solid low-level radioactive waste (LLW) from nuclear power plants is generated from the
removal of radionuclides from liquid waste streams, filtration of airborne gaseous emissions,
and removal of contaminated material from various reactor areas. Liquid contaminated with
radionuclides comes from primary and secondary coolant systems, spent fuel pools,
decontaminated wastewater, and laboratory operations.
Solid waste is packaged in containers to meet the applicable requirements of 49 CFR Parts 171
through 177. Disposal and transportation are performed in accordance with the applicable
requirements of 10 CFR Part 61 and 10 CFR Part 71, respectively.
Solid radioactive waste generated during operations is shipped to a LLW processor or directly to
a LLW disposal site. Volume reduction may occur both onsite and offsite. The most common
onsite volume reduction techniques are high-pressure compacting in waste drums, dewatering
and evaporating wet wastes, monitoring waste streams to segregate wastes, and sorting. Offsite
waste management vendors compact wastes at ultra-high pressures, incinerate dry active
waste, separate and incinerate oily and organic wastes, and concrete-solidify resins and
sludges before the waste is sent to a LLW disposal site.
Spent fuel contains fission products and actinides produced when nuclear fuel is irradiated in
reactors, as well as any unburned, unfissioned nuclear fuel remaining after the fuel rods have
been removed from the reactor core. In the United States, the spent fuel is considered waste
and is being stored at the reactor sites, either in spent fuel pools or dry storage facilities, called
ISFSIs (see Section 3.11.1.2). While all spent fuel is currently stored at nuclear power plant
sites, the NRC has licensed two consolidated interim storage facility ISFSIs, one in Andrews,
Texas, and the other in Lea County, New Mexico (NRC 2021h, NRC 2023b).2 Consolidated
interim storage facilities are licensed under 10 CFR Part 72 and provide an option for
away-from-reactor spent fuel storage.
Mixed wastes, which contain both radioactive and hazardous components, are generally
accumulated in designated areas onsite and then shipped offsite for treatment and disposal.
Mixed wastes are regulated both by the EPA or the State under authority granted by the
Resource Conservation and Recovery Act (RCRA; 42 U.S.C. § 6901 et seq.) and by the NRC or
the State under authority granted by the Atomic Energy Act (AEA; 42 U.S.C. § 2011 et seq.)
(see Section 3.11.3).

2

On August 25, 2023, the U.S. Court of Appeals for the Fifth Circuit issued a decision regarding the
NRC’s statutory authority to license a private, away-from-reactor storage facility for spent nuclear fuel and
vacated the NRC’s license issued to Interim Storage Partners, LLC’s license for a spent fuel storage
facility in Andrews County, Texas. As of the time of writing, the NRC had appealed that decision on
October 24, 2023.

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3.1.5

Nonradioactive Waste Management Systems

Nonradioactive wastes from nuclear power plants include both hazardous and nonhazardous
wastes. Hazardous wastes, as defined by RCRA Subtitle C, may include organic materials,
heavy metals, solvents, paints, cutting fluids, and lubricating oils that have been used at a
nuclear power plant and, after use, have been declared to be waste. These wastes are
generally accumulated in designated areas onsite and then shipped offsite for treatment and
disposal. Certain hazardous waste streams may receive treatment at some sites. For example,
waste oil is incinerated at some sites. Common treatment methods for these nonradioactive
wastes include incineration, neutralization, biological treatment, and removal and recovery.
All activities related to hazardous wastes—including storage, treatment, shipment, and
disposal—are conducted pursuant to the regulations issued by the EPA or the State, if
authorized, under RCRA (see Section 3.11.2).
There are also some routine or nonroutine releases from nuclear power plants that may have
hazardous components, including boiler blowdown (continual or periodic purging of impurities
from plant boilers), water treatment wastes (sludges and high-saline streams whose residues
are disposed of as solid waste and biocides), boiler metal cleaning wastes, floor and yard
drains, and stormwater runoff. With the exception of solid water treatment wastes, these
releases are regulated in accordance with each plant’s NPDES permit. Principal chemical and
biocide waste sources include the following:
• Boric acid used to control reactor power and lithium hydroxide used to control pH in the
coolant. These chemicals could be inadvertently released because of pipe or steam generator
leakage.
• Sulfuric acid, which is added to the circulating water system to control scale.
• Hydrazine, which is used for corrosion control. It is released in steam generator blowdown.
• Sodium hydroxide and sulfuric acid, which are used to regenerate resins. These are
discharged after neutralization.
• Phosphate in cleaning solutions.
• Biocides (e.g., chlorine and bromine compounds) used for condenser defouling.
Other small volumes of wastewater are released from other plant systems depending on the
design of each plant. These volumes are discharged from sources such as the service water
and auxiliary cooling systems, laboratory and sampling wastes, and metal treatment wastes.
These waste streams are regulated and discharged in accordance with each plant’s NPDES
permit as separate point sources or are combined with the cooling water discharges.
Nonradioactive and nonhazardous wastes such as office trash are picked up by a local waste
hauler and sent to a local landfill without any treatment. Sanitary wastes are treated at a sewage
treatment plant that is located either onsite or offsite. If the treatment plant is offsite, the sanitary
waste is either collected in septic tanks, tested for radioactivity as necessary, and sent offsite
periodically, or the sanitary waste may be tested for radioactivity and discharged directly to a
publicly owned treatment works. Any effluent releases to surface water from sewage plants are
subject to NPDES permit limits.

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3.1.6

Utility and Transportation Infrastructure

As with other industrial facilities, the utility and transportation infrastructure at nuclear power
plants typically interfaces with public infrastructure systems available in the region. This
infrastructure includes utility systems and resources such as electricity, fuel, and water, as well
as roads and railroads used to gain access to the nuclear power plant sites. Section G.1.1.2 in
Appendix G, describes a nuclear power plant’s utility and transportation infrastructure in greater
detail.
3.1.7

Power Transmission Systems

Each nuclear power plant is connected to an independent regional electrical power distribution
grid. Power transmission systems consist of switching stations (or substations) and the
transmission lines that transfer electricity from the nuclear power plant to the regional grid.
Switching stations transfer electrical power from generating sources to transmission lines and
regulate the operation of the power system. Transformers in switching stations convert the
generated voltage to levels appropriate for the transmission lines based on the rating of the
lines. Equipment for regulating system operation includes switches, power circuit breakers,
meters, relays, microwave communication equipment, capacitors, and a variety of other
electrical equipment. This equipment meters and controls power flow; improves the
performance characteristics of the generated power; and protects generating equipment from
short circuits, lightning strikes, and switching surges that may occur along the transmission
lines. At nuclear power plant sites, switching stations generally occupy areas two to four times
as large as areas occupied by the reactor and generator buildings, but they are typically not as
visible as other plant structures.
Only those transmission lines that connect the nuclear power plant to the first substation where
electricity is fed into the regional electric distribution system and power lines that provide power
to the plant from the grid are considered within the regulatory scope of initial LR or SLR.
The original final environmental statements for the construction and operation of nuclear power
plants also evaluated the impacts of constructing and operating transmission lines needed to
connect nuclear power plants to the regional electric grid. Since construction, many of these
transmission lines have been incorporated into the regional grid. In many cases, these
transmission lines are no longer owned or managed by NRC licensees and would remain
energized regardless of nuclear power plant license renewal. As such, these transmission lines
are outside of the scope of this LR GEIS.
3.1.8

Nuclear Power Plant Operations and Maintenance

Nuclear power reactors are capable of generating electricity continuously for long periods of
time. However, they do not operate at maximum capacity or continuously for the entire term of
their license. Plants can typically operate continuously for periods of time ranging from 1 year to
2 years on a single fuel load.
Maintenance activities are routinely performed on systems and components to help ensure the
safe and reliable operation of the plant. In addition, inspection, testing, and surveillance
activities are conducted throughout the operational life of a nuclear power plant to maintain the
current licensing basis of the plant and ensure compliance with Federal, State, and local
requirements regarding the environment and public safety.

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Nuclear power plants must periodically discontinue the production of electricity for refueling,
periodic in-service inspection (ISI), and scheduled maintenance. Refueling cycles occur
approximately every 12 to 24 months. The duration of a refueling outage is typically about 1 to
2 months. These enhanced inspections and maintenance activities are performed to comply
with NRC and/or industry standards or requirements, such as the American Society of
Mechanical Engineers Boiler and Pressure Vessel Code. ISIs are generally scheduled and
performed during 10-year intervals as follows: the initial period of operation (the first 40 years)
includes the 1st through 4th intervals, an initial period of extended operation (years 40 through
60) would include the 5th and 6th intervals, and a subsequent period of extended operation
(years 60 through 80) would include the 7th and 8th intervals, and are subject to the
requirements of 10 CFR 50.55(a), “Codes and Standards.” For economic reasons and
component accessibility, many of these activities are conducted simultaneously (e.g., refueling
activities typically coincide with the ISI and maintenance activities).
Many plants also undertake various major refurbishment activities during their operational lives.
These activities are performed to ensure both that the plant will continue to be operated safely
and that the capacity and reliability of the plant remain at acceptable levels. Typical major
refurbishments that have occurred in the past include replacing PWR steam generators, reactor
vessel heads, BWR recirculation piping, and rebuilding main steam turbine stages. The need to
perform major refurbishments is plant-specific and depends on factors such as design features,
operational history, and construction and fabrication details. The plants may remain out of
service for extended periods of time (e.g., several months) while these major refurbishments are
made. Outage durations vary considerably, depending on factors such as the scope of the
repairs or modifications undertaken, the effectiveness of the outage planning, and the
availability of replacement parts and components.
Each nuclear power plant may be part of a regulated utility system that may own several nuclear
power plants, fossil fuel-fired plants, or other means of generating electricity for sale in a
regulated market. Other nuclear power plants may be non-utility or independent power
generators operating to produce and sell electricity at competitive wholesale power rates.
An onsite staff is responsible for the actual operation of each plant, and an offsite staff may be
headquartered at the plant site or some other location. Typically, 800 to 2,300 people are
employed at nuclear power plant sites during periods of normal operation, depending on the
number of operating reactors located at a particular site. The permanent onsite workforce is
usually in the range of 600 to 800 people per reactor unit. However, during outage periods, the
onsite workforce typically increases by 200 to 900 additional workers. The additional workers
include engineering support staff, technicians, specialty crafts persons, and laborers called in
both to perform specialized repairs, maintenance, tests, and inspections, and to assist the
permanent staff with the more routine activities carried out during plant outages.

3.2
3.2.1

Land Use and Visual Resources
Land Use

Nuclear power plants are located on land zoned for industrial use in large complexes and land
area requirements generally are 100 to 125 ac (40 to 50 ha) for the reactor containment
building, auxiliary buildings, cooling system structures, administration and training offices, and
other facilities (e.g., switchyards, security facilities, and parking lots). Land areas disturbed
during construction of the power plant generally have been returned to prior uses or were
ecologically restored when construction ended. Land area ranges from 391 ac (158 ha) for the
Catawba Nuclear Station (Catawba) in North Carolina to 14,000 ac (5,700 ha) for the Clinton

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Power Station (Clinton) in Illinois (Table 3.1-1). Almost 58 percent of nuclear power plants
encompass 500 to 2,000 ac (200 to 800 ha); 18 nuclear plants range from 500 to 1,000 ac
(200 to 400 ha); and an additional 14 encompass 1,000 to 2,000 ac (400 to 800 ha). Larger land
areas are often associated with human-made closed-cycle cooling systems that include cooling
lagoons, spray canals, reservoirs, artificial lakes, and buffer areas.
In addition to generating electricity, other land uses can be found. Some nuclear plant licensees
lease land for agricultural and forestry production, nature centers and conservation areas,
recreational use, and cemetery and historic site access. Nuclear plants also have land set aside
for onsite spent fuel storage facilities (see Section 3.1.4.3).
Land cover and land use percentages at each nuclear power plant depend on the total area and
amount of land required for electric power generation. Land cover is generally designated within
the land use “resource-oriented” classification system, which includes urban or built-up land,
agricultural land (e.g., cropland, pasture, orchards, nurseries, fields, and fallow lands),
rangeland, forest land, water, wetland (e.g., marshes and swamps), and barren land
(e.g., beaches and gravel pits). Land cover designations can also use visually descriptive
categories that include open areas (e.g., fields, cemeteries), forested areas, scrub forest,
deciduous forest, hardwood forest, beach, wetlands, open water (e.g., ponds, streams, lakes,
and canals), natural lands, recreational lands, and parking areas.
Land use within transmission line right-of-ways (ROWs) is restricted under easement rights
acquired from private landowners or from Federal, State, Tribal, and local governments. Land
use within ROWs may differ from adjacent land use. Land within the ROW is managed through
a variety of oversight and maintenance procedures so that vegetation growth and building
construction do not interfere with power line operation, maintenance, and access. Land use
within ROWs is limited to activities that do not endanger line operation and may include
recreation, off-road vehicle use, grazing, agricultural cultivation, irrigation, recreation, roads,
environmental conservation, and wildlife areas.
Land cover within a 5 mi (8 km) radius of operating U.S. nuclear power plants, using the
National Land Cover Database (USGS 2019a) classifications, is presented in Table 3.2-1. Land
cover types near each nuclear plant site are also presented in Appendix C.
Section 307(c)(3)(A) of the Coastal Zone Management Act of 1972 (16 U.S.C. § 1456 et seq.)
requires that license renewal applicants certify that the proposed Federal license renewal in a
coastal zone or coastal watershed boundary, as defined by each State participating in the
National Coastal Zone Management Program, is consistent with the enforceable policies of that
State’s Coastal Zone Management Program. States define their coastal zone boundaries by
using a variety of parameters, such as the entire State, county or county-equivalent boundaries,
political features (e.g., town boundaries), and geographic features (adjacency to tidal waters).
Applicants must coordinate with the State agency that manages the State Coastal Zone
Management Program to obtain a determination that the proposed nuclear plant license renewal
is consistent with their program.

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Table 3.2-1

Percent of Land Cover Types within a 5-Mile Radius of Nuclear Power
Plants
Land Cover Classes

Open water (total)
Undeveloped land (total)
Barren land
Forest (deciduous, evergreen, and mixed)
Wetlands
Herbaceous
Shrub/scrub
Developed land (total)
Agriculture (cultivated crops and hay/pasture)
Developed open space
Low to high intensity developed land
Total

Overall (%)
23.5
43.1
0.3
23.5
10.9
4.2
4.2
33.4
22.2
4.5
6.7
100

Sources: USGS 2019a; Pacific Northwest National Laboratory calculations.

3.2.2

Visual Resources

Nuclear power plants—particularly those with tall natural draft cooling towers—stand out from
the natural background. Power plant structures can be seen from a distance and across a wide
area. Cooling towers can also draw attention because of their vapor plumes. These plumes,
seen under certain meteorological and seasonal conditions, can extend the viewshed
considerably beyond that of the cooling tower and power plant alone. After cooling towers and
the containment building, transmission line towers are probably the most frequently observed
power plant structure. However, nuclear plant transmission lines are generally indistinguishable
from those from other power plants. In addition, nuclear power plant structures are often
obscured by topography, other buildings, and vegetation.
Most nuclear plants have employed a variety of mitigation measures to decrease the visual
intrusion, including cladding and paint colors used to blend in with the surroundings,
nonreflective surfaces, and the placement of trees and other landscaping. Federal regulations
require that tall structures, including the reactor containment building, cooling towers, stacks,
and meteorological towers, be fitted with lights to alert aircraft of their presence. Often these
structures can be visible at night from miles away.
Because nuclear power plants are frequently located near waterbodies, views of the industrial
facility and transmission lines intrude into recreational, historic, or scenic areas. Most of the
visual impacts from transmission lines are associated with river crossings, wetlands, wildlife
sanctuaries, open parks and athletic fields, roads, lakes, cemeteries, and historic battlefields.

3.3
3.3.1

Meteorology, Air Quality, and Noise
Meteorology and Climatology

The NRC requires that basic meteorological information be available for use in assessing
(1) the environmental effects of radiological and nonradiological emissions and effluents
resulting from the construction or operation of a nuclear power plant and (2) the benefits
of design alternatives. All nuclear power plants in the United States have a required
onsite meteorological monitoring program to provide the data needed to determine
dispersion conditions in the vicinity of the plant for assessment of safety and environmental

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factors. These data are used with air dispersion models to assess and protect public
health, safety, and property during plant operations (NRC 2007e).
The most recent update to NRC Regulatory Guide 1.23, Meteorological Monitoring Programs for
Nuclear Power Plants, Revision 1 (NRC 2007e), which covers meteorological monitoring
programs for nuclear power plants, provides guidance for onsite meteorological measurements
at licensed power reactors. The guidance covers the siting of instruments to provide
representative measures at plant sites, the accuracy and range of specified measured
parameters, and special considerations for plants located near influences of complex terrain
(e.g., coastal areas, hills of significant grade or valleys), among other criteria and specifications.
Onsite meteorological conditions at commercial nuclear power plants are monitored at primary
fixed meteorological towers with instrumentation at two levels (e.g., 10 and 60 m) and, if
necessary, one additional higher level on the tower to better represent dispersion of elevated
releases from stacks. A secondary onsite tower is typical at many installations as a backup if
primary tower measures fail. Basic meteorological measurements from tower instruments
typically include the following: (1) wind speed and direction from at least two levels;
(2) temperature for an ambient reading at 33 ft (10 m) and to determine deltas or changes with
height; and (3) precipitation, which is typically measured near ground level by the tower base.
Supplemental measurements can include moisture at 33 ft (10 m) and, if applicable, incoming
solar and net radiation, barometric pressure, soil temperature, and moisture at the top of the
cooling tower. Atmospheric stability is determined from temperature differences at the two
lowest levels on the tower. If a backup tower is present, measurements include wind speed and
direction and horizontal wind direction variation, usually taken at one level.
Weather conditions at each of the plants can be quite variable depending on the year, season,
time of day, and site-specific conditions, such as whether the site is near coastal zones or
located in or near terrain with complex features (e.g., steep slopes, ravines, valleys). These
conditions can be generally described by climate zones according to average temperatures.
Based on temperature alone, there are three major climate zones: polar, temperate, and
tropical. Within each of the three major climate zones, there are marine and continental
climates. Areas near an ocean or other large body of water have a marine climate. Areas
located within a large landmass have a continental climate. Typically, areas with a marine
climate receive more precipitation and have a more moderate climate. A continental climate has
less precipitation and a greater range in climate. Regional or localized refinements in climate
descriptions and assessments can be made by considering other important climate variables
and climate-influencing geographic variables, such as precipitation, humidity, surface
roughness, proximity to oceans or large lakes, soil moisture, albedo, snow cover, and
associated linkages and feedback mechanisms. Localized microclimates can be defined by
considering factors such as urban latent and sensible heat flux and building-generated
turbulence. Both national and regional maximum and minimum average annual temperature and
precipitation climatologies over the 30 years from 1991 through 2020 are summarized in
Section G.3.1 in Appendix G.
The National Climatic Data Center records and archives the occurrence of storms and weather
phenomena. The National Climatic Data Center documents this information in a database that
dates back to January 1950 (NOAA 2023a). Severe weather events recorded include floods,
thunderstorms, hurricanes, and tornadoes. Table 3.3-1 provides the current enhanced Fujita
(EF) scale next to the original Fujita (F) scale, adjusted to represent peak winds averaged over
3 seconds, which are used to identify a tornado event’s intensity. The EF scale (WSEC 2006) is
based on the highest wind speed estimated in the tornado path with maximum 3-second

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average wind gusts within the range specified for each EF intensity level. The range in damage
to structures in the EF2 through EF5 range is described as considerable to incredible, and the
damage depends highly on the building’s structural design.
Table 3.3-1

Intensity
F0/EF0
F1/EF1
F2/EF2
F3/EF3
F4/EF4
F5/EF5

Description
of Damage
Light
Moderate
Considerable
Severe
Devastating
Incredible

Fujita Tornado Intensity Scale
Original Fujita Scale
(3-s gust) (mph)
45 to 78
79 to 117
118 to 161
162 to 209
210 to 261
262 to 317

Operational Enhanced
Fujita Scale
(3-s gust) (mph)
65 to 85
86 to 110
111 to 135
136 to 165
166 to 200
>200

EF = enhanced Fujita scale; F = Fujita scale; mph = miles per hour; s = second.
Source: WSEC 2006.

3.3.2

Air Quality

Air emissions related to criteria air pollutants and volatile organic compounds (VOCs) (a
precursor of ozone) are released to the atmosphere from ancillary non-nuclear equipment at
nuclear power plants. These emissions include criteria air pollutants such as particulate matter
(PM) with a mean aerodynamic diameter of 10 μm or less (PM10), PM with a mean aerodynamic
diameter of 2.5 μm or less (PM2.5), sulfur dioxide (SO2), nitrogen oxides (NOx),3 carbon
monoxide (CO), lead, and VOCs.
The EPA has set National Ambient Air Quality Standards (NAAQS) for six criteria pollutants,
including SO2, nitrogen dioxide (NO2), CO, ozone, PM10, PM2.5, and lead, as shown in
Table 3.3-2. Primary NAAQS specify maximum ambient (outdoor air) concentration levels of the
criteria pollutants with the aim of protecting public health. Secondary NAAQS specify maximum
concentration levels with the aim of protecting public welfare. The NAAQS specify different
averaging times as well as maximum concentrations. Some of the NAAQS for averaging times
of 24 hours or less allow the standard values to be exceeded a limited number of times per
year, and others specify other procedures for determining compliance. States can have their
own State Ambient Air Quality Standards. State Ambient Air Quality Standards must be at least
as stringent as the NAAQS and can include standards for additional pollutants. If a State has no
standard corresponding to one of the NAAQS, the NAAQS apply.
An area where criteria air pollutants exceed NAAQS levels is called a nonattainment area.
Previous nonattainment areas where air quality has improved to meet the NAAQS are
redesignated maintenance areas and are subject to an air quality maintenance plan.

3

NOx is not a criteria pollutant, but emissions are typically reported in terms of NO x. Nitrogen dioxide
(NO2) is the component of NOx that is a criteria pollutant, but emissions of NO2 are not typically reported.

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The currently designated nonattainment areas (as of February 2020)4 for each criteria air
pollutant (8-hour ozone, PM10, PM2.5, SO2, NO2, CO, and lead) and their relative locations with
respect to operating nuclear power plants are shown on the map in Figure 3.3-1. There are
currently more than 30 operating plants located within or adjacent to counties with designated
nonattainment areas. There are no nonattainment areas designated for CO or NO2.
Table 3.3-2

National Ambient Air Quality Standards for Six Criteria Pollutants(a)

Pollutant
SO2
SO2
NO2
NO2
CO
CO
O3
PM10
PM2.5
PM2.5
PM2.5
Pb

NAAQS Value(b)
75 ppb
0.5 ppm
100 ppb
0.053 ppm (53 ppb)
35 ppm
9 ppm
0.070 ppm
150 μg/m3
35 μg/m3
15 μg/m3
12 μg/m3
0.15 μg/m3

Averaging Time
1-hour
3-hour
1-hour
Annual
1-hour
8-hour
8-hour
24-hour
24-hour
Annual
Annual
Rolling 3-month

NAAQS Type(c)
P
S
P
P, S
P
P
P, S
P, S
P, S
S
P
P, S

(a) CO = carbon monoxide; NAAQS = National Ambient Air Quality Standards; NO2 = nitrogen dioxide; O3 = ozone;
Pb =lead; PM2.5 = particulate matter  2.5 μm; PM10 = particulate matter  10 μm; ppb = parts per billion;
ppm = parts per million; SO2 = sulfur dioxide.
(b) Refer to 40 CFR Part 50 or EPA 2023g for detailed information about attainment determination and reference
method for monitoring.
(c) P = Primary standard whose limits were set to protect public health; S = secondary standard whose limits were
set to protect public welfare.
Source: EPA 2023g.

Nonattainment area designations are ever-changing and redesignations may occur due to EPA’s
revisions for PM10 and PM2.5 (effective March 18, 2013), 8-hour ozone (effective October 26, 2015), Pb
(effective January 12, 2009),1-hour SO2 (effective August 23, 2010), and 1-hour NO2 (effective April 12,
2010). Please refer to the latest EPA Green Book for the most updated nonattainment and maintenance
area designations (available URL: http://www.epa.gov/green-book/).
4

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NUREG-1437, Revision 2

Figure 3.3-1 Locations of Operating Nuclear Plants Relative to U.S. Environmental Protection Agency Nonattainment
Areas. Adapted from EPA 2022e. Revoked 1-hour (1979) and 8-hour (1997) Ozone are Excluded.

Affected Environment
Sources at nuclear power plants that contribute to criteria air pollutants include backup diesel
generators, boilers, fire pump engines, and cooling towers. The emissions from these sources
(and, if applicable, emissions from the incineration of any waste products) must comply with
State and local regulatory air quality permitting requirements. Because nuclear power plant
ancillary equipment are generally low emitters of criteria air pollutants and VOCs, the impact on
potential ambient air quality is minimal. However, special permit conditions may be applicable
under various regulatory jurisdictions for facilities located in EPA designated nonattainment
areas.
The operation of wet cooling towers results in the emission of salt and other inorganic and/or
organic particles to the air. These releases are called drift emissions. Salt is the dominant drift
component—being typically greater than 70 percent of the total suspended PM released—for
coastal nuclear plants with wet towers that use seawater as the coolant. Drift emissions from
cooling towers are also associated with deposits on downwind surfaces (e.g., vegetation,
automobiles, and structures), known as drift deposition, and a resulting increase in downwind
PM concentrations. The magnitude and pattern of these impacts could include both near-field
and far-field receptors. The degree of impacts would depend on a number of factors, such as
the size of the particles, the steam condenser flow rate or throughput, and the type and height of
the cooling tower.
Cooling tower particulate emissions are formed entirely as secondary particles from evaporation
of wet tower drift droplet releases to the atmosphere. Because the drift droplets generally
contain the same chemical impurities (primarily dissolved solids) as those in the cooling water
circulating through the tower, these impurities wind up in the drift that escapes the tower. Large
drift droplets settle out of the tower’s exhaust air stream and are deposited on surfaces near the
tower. This process can lead to wetting, icing, and salt deposition and can cause related
problems, such as damage to equipment or vegetation. Other drift droplets may evaporate and
form mixed chemical particles from water-soluble materials (total dissolved solids or TDS), such
as sea salt, and water-insoluble (total suspended solids) droplet-encapsulated particles
(Pruppacher and Klett 1980) that are transported in the air as suspended PM before being
deposited on surfaces downwind. Both PM10 and PM2.5 are generated when the drift droplets
evaporate and leave fine PM formed by the crystallization of dissolved solids. Dissolved solids
found in cooling tower drift can consist of salt compounds (e.g., sodium chloride, sodium nitrate,
ammonium sulfate [(NH4)2SO4] and other mineral matter), corrosion inhibitors, and biocides.
The magnitude of drift-related PM10 and PM2.5 emissions from wet towers depends on several
conditions and parameters, such as the makeup water composition, concentrations of TDS
(organic matter, biocides, corrosion inhibitors, sodium chloride), steam condenser flow rate, drift
eliminator efficiency, number of cooling towers/cells, and annual hours of operation. In
comparison, drift emissions from cooling tower systems using seawater are over 7 times greater
than those from systems supplied with freshwater makeup feeds, if everything else is held
constant. Palo Verde Nuclear Generating Station (Palo Verde) in Arizona uses makeup water
derived from the Phoenix City Sewage Treatment Plant. The associated drift emissions from the
six mechanical draft cooling towers at the Palo Verde plant in 2017 were less than 32 and
20 tons for PM10 and PM2.5, respectively (MCAQD 2019). These emissions are relatively small
and typical for a well-controlled cooling tower using a water supply with low TDS concentration
levels. Palo Verde’s air permit issued by the Maricopa County Air Quality Department requires
that TDS concentration for each cooling tower be limited to 30,000 ppm (MCAQD 2010).
There is only one plant, Hope Creek in New Jersey, that uses high-salinity water (from the
Delaware River Estuary) as the coolant in a natural draft cooling tower. An analysis of drift

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emissions and air impacts from Hope Creek’s natural draft cooling tower was assessed with air
quality modeling conducted in support of an extended power uprate from about 3,300 to about
3,800 megawatts-thermal (NRC 2008b). The analysis showed that the uprate would increase
the particulate cooling tower drift emissions from the current rate of 29.4 pounds per hour (lb/hr)
(13.3 kilograms per hour [kg/hr]) to an average rate of 35.6 lb/hr (16.1 kg/hr, with a maximum of
42.0 lb/hr [19.1 kg/hr]). Particulates (primarily salts) from the cooling tower are primarily PM10.
Although smaller suspended drift particles would also likely be generated from evaporation of
cooling tower plume droplets, estimates of the size distribution of generated drift particles to
determine the PM2.5 fraction were not made. The NRC staff determined that the estimated
increase in particulate emissions would exceed the New Jersey Department of Environmental
Protection’s (NJDEP’s) regulatory maximum hourly emission limit of 30 lb/hr (13.6 kg/hr) for
particulates (NJ Admin. Code 7:27-6). However, the NJDEP’s Bureau of Technical Services
reviewed the air quality modeling conducted in support of the proposed power uprate and
determined that the cooling tower emissions would not exceed the NAAQS for PM10 or
New Jersey’s Ambient Air Quality Standards for PM10. Based on this determination, the NRC
staff concluded that there would be no significant particulate emission impacts associated with
the Hope Creek plant’s cooling tower at the associated higher makeup water throughput
necessary to sustain the higher requested plant operating loads (NRC 2008b). On
June 13, 2007, NJDEP issued its final Title V air permit for the Hope Creek cooling tower,
authorizing a variance to the plant’s air operating permit with an hourly emission rate of 42 lb/hr
(19.1 kg/hr) (State of New Jersey 2021). In addition, a prevention of significant deterioration
(i.e., PSD) applicability determination by the EPA concluded that the requested power uprate
would not result in a significant increase in emissions and would not be subject to prevention of
significant deterioration review (State of New Jersey 2021). Further regulatory review was not
required since the Hope Creek plant is located in an attainment area for PM10.
Transmission lines have been associated with the production of minute amounts of ozone and
NOx. These pollutants are associated with corona—the breakdown of air that is very near
high-voltage conductors. Corona is a phenomenon associated with all energized transmission
lines. Under certain conditions, the localized electric field near an energized conductor can be
sufficiently concentrated to produce a tiny electric discharge that can ionize air close to the
conductors (EPRI 1982). This partial discharge of electrical energy is called corona discharge,
or corona. Corona is most noticeable for higher-voltage lines during rain or fog conditions. In
addition to the small quantities of ozone and NOx that form, other manifestations of corona
events include energy loss, interference with radio or television transmission, and ambient noise
(see Section 3.3.3). Typically, corona interference with radio and television reception is not a
design problem. Interference levels in both fair and rainy weather are extremely low at the ROW
edge for 230-kV and lower transmission lines, and they usually meet or exceed the reception
guidelines of the Federal Communications Commission. As discussed in the 2013 LR GEIS,
through the years, line designs that greatly reduce corona effects have been developed.
Because transmission line emissions associated with corona discharge are so small when
compared with emissions from other sources of air pollution (e.g., ozone precursors from
automobiles, power plants, and large industrial boilers), these emissions are not a regulated
source of air pollution in the United States.
Airborne radiological releases during normal plant operation and associated doses to downwind
populations are discussed in Section 3.9.

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3.3.3

Noise

Noise is unwanted sound that can be generated by many sources. Sound intensity is measured
in logarithmic units called decibels (dB). A dB is the ratio of the measured sound pressure level
to a reference level equal to a normal person’s threshold of hearing. Another characteristic of
sound is frequency or pitch. Noise may be comprised of many frequencies, but the human ear
does not hear very low or very high frequencies. To represent noise as closely as possible to
the noise levels people experience, sounds are measured using a frequency-weighting scheme
known as the A-scale. Sound levels measured on this A-scale are given in units of A-weighted
decibels (dBA). Levels can become very annoying at 85 dBA. To the human ear, an increase of
3 dBA is barely noticeable and an increase of 10 dBA sounds twice as loud (EPA 1981).
Several different terms are commonly used to describe sounds that vary in intensity over time.
The equivalent sound intensity level represents the average sound intensity level over a
specified interval, often 1 hour. The day-night sound intensity level is a single value calculated
from hourly equivalent sound intensity level over a 24-hour period, with the addition of 10 dBA to
sound levels from 10 p.m. to 7 a.m. This addition accounts for the greater sensitivity of most
people to nighttime noise. Statistical sound level (Ln) is the sound level that is exceeded ‘n’
percent of the time during a given period. For example, L90, is the sound level exceeded
90 percent of the time and is considered the background level.
The principal sources of noise from nuclear power plant operations are natural draft and
mechanical draft cooling towers, transmission lines, and transformers. Other occasional and
intermittent noise sources may include auxiliary equipment (such as pumps to supply cooling
water), main steam safety valves, corona discharge, firing range, and loudspeakers. In most
cases, the sources of noise are far enough away from sensitive receptors outside plant
boundaries that the noise is attenuated to nearly ambient levels and is scarcely noticeable.
There are no Federal regulations for public exposures to noise. When noise levels are below the
levels that result in hearing loss, impacts have been judged primarily in terms of adverse public
reactions to noise. The Department of Housing and Urban Development (24 CFR 51.101(a)(8))
uses day-night average sound levels of 55 dBA, recommended by EPA as guidelines or goals
for outdoors in residential areas (EPA 1974). However, noise levels are considered acceptable if
the day-night average sound level outside a residence is less than 65 dBA.
Natural draft and mechanical draft cooling towers emit noise of a broadband nature. Cooling
tower noise is generated by fan equipment or falling water. At 164 ft (50 m) distance, noise level
for a mechanical draft cooling tower can reach 60 dBA and at 230 ft (70 m) distance the noise
level for a natural draft cooling tower can reach 66 dBA (Tetra Tech 2010; Neller and
Snow 2003).
Transformers emit a humming noise of a specific tonal nature at twice the normal voltage or
current frequency (core expansion and contraction twice its 60 hertz [Hz] cycle) with a vibration
or noise harmonic of 120 Hz. This is called the fundamental noise frequency. Transformer noise
originates almost entirely in the core as a result of the restrictive effects of steel on the
generated magnetic field, a phenomenon called magnetostriction, which causes the core and its
clamps to vibrate (Ellingson 1979). Since the core is not symmetrical and the magnetic effects
do not behave in a simple way, the resultant noise is not pure in tone. This is the noise or
vibration produced. The noise radiated by transformers is primarily composed of discrete tones
at even harmonics of line frequency (e.g., 120, 240, 360 Hz) when the line frequency is 60 Hz
(Vér and Beranek 2005). Transformer noise is distinct because of its specific low frequencies.

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The low frequencies are not attenuated with distance and intervening materials as much as
higher frequencies are; thus, low frequencies are more noticeable and obtrusive. However, at
most sites employing cooling towers, transformer noise is masked by the broadband cooling
tower noise. Sound levels from transformers varies depending on the capacity rating.
Transmission lines can generate a small amount of sound energy during corona activity. During
corona events (see Section 3.3.2), the ionization of the air that surrounds conductors of the
high-voltage transmission lines, which is caused by electrostatic fields in these lines, generates
impulse corona currents. When the voltage on a particular phase is high enough, a corona burst
occurs, and a noise is generated. This noise occurs primarily on the positive power line voltage
wave and is referred to as positive corona noise (Maruvada 2000).
Although conductors are designed to minimize corona discharges, surface irregularities caused
by damage, insects, raindrops, or contamination may locally enhance the electric field strength
enough for corona discharges to occur (Cristina and D’Amore 1985). This audible noise from
the line can barely be heard in fair weather on higher-voltage lines. During wet weather, water
drops collect on the conductor and increase corona activity so that a crackling or humming
sound may be heard near the line. This noise is caused by small electrical discharges from the
water drops. Measurements from a 765 kV transmission line during rain events found that the
average sound levels at 50 ft (15 m) from the transmission line were 54.6 dBA, with sound
levels as high as 64 dBA measured (Popeck and Knapp 1981).
Cooling tower and transformer noise from existing equipment does not change appreciably
during the time when the plant is operating, nor does the crackling sound of transmission lines
during storms. Increases or decreases in site noise levels can occur when equipment is
upgraded or modified to meet life-cycle maintenance requirements or when the power level is
uprated.

3.4

Geologic Environment

The geologic environment of a nuclear power plant site encompasses the physiographic or
physical setting in which the plant has been constructed and the associated geologic strata and
soils that comprise the site. Large-scale geologic hazards are a condition of the geologic
environment and include geologic faulting and earthquakes that comprise a site’s seismic setting.
Nuclear power plants are located in a variety of physiographic provinces, though most nuclear
plants are located in the Atlantic Coastal Plain and Central Lowlands provinces. Each
physiographic province consists of a regional geologic terrain with a broadly similar structure
and character. However, within each province, the local geology may differ significantly from the
regional conditions. The geologic setting of each nuclear plant is therefore more a reflection of
the local geology rather than the physiographic province in which it is located. Nuclear power
plants are located in a wide variety of settings, including uplands along rivers, glaciated till
plains, Great Lakes shorelines, and coastal sites. As a result, the geologic strata on which
plants have been sited and constructed range from variably textured, interbedded,
unconsolidated to semi-consolidated sediments of relatively recent age (i.e., less than
11,700 years before present), to thick sequences of sedimentary rock (e.g., sandstone, shale,
siltstone) of varying age, to massive crystalline igneous and metamorphic rocks (e.g., granitic
and gneissic rocks) as old as Precambrian (i.e., greater than 540 million years before present).
All safety-related structures (e.g., seismic Category 1 structures) at nuclear power plants are
founded either on competent bedrock, engineered compacted strata, concrete fill, and/or
structural backfill in order to make sure that no safety-related facilities are constructed in
potentially unstable materials.

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Soils across a plant site come from the disintegration of parent materials (i.e., bedrock or
sediments) and interaction with the atmosphere and biological action and can develop distinct
horizons or layers with varying properties and uses. Soils and subsoils at nuclear plant sites
vary in terms of the geotechnical properties relevant to site construction (e.g., shear-strength,
shrink-swell potential, cut-slope stability, and erodibility) and the hydraulic properties related to
the infiltration of water at the soil surface, the occurrence of groundwater, and the movement of
contaminants. Depending on the nuclear plant’s location and design, riverbanks or coastlines
may need to be protected to prevent erosion, especially at water intake or discharge structures.
The soil resources available at each nuclear power plant are site-specific in terms of their
potential erodibility and their potential use for agricultural activities and vary spatially based on
the distribution of different soil types on the site. Many of the nuclear plants in the Midwest,
Great Plains, East, and Southeast (with the exception of plants in Florida) are located in areas
with soils that are designated as prime farmland (see Figure 3.4-1). Prime farmland soil has the
best combination of physical and chemical characteristics for growing crops and is potentially
subject to the Farmland Protection Policy Act of 1981 (FPPA; 7 U.S.C. § 4201 et seq.) and its
implementing regulations (7 CFR Part 657 and Part 658). Other important farmland soils
potentially subject to the FPPA include unique farmlands as well as farmlands designated as
having statewide or local importance. Farmland subject to FPPA regulation does not have to be
currently used for cropland. It can be forest land, pastureland, cropland, or other land, but not
water or urban built-up land.
While the FPPA could apply in some circumstances at nuclear power plant sites (e.g.,
development of renewable energy projects as an alternative to license renewal or other projects
completed with Federal assistance including funding), it does not apply to Federal permitting or
licensing actions for activities on private or non-Federal lands (7 CFR Part 658). Nuclear plants
in Florida and in Western States are generally not located near prime or other important
farmland. At some nuclear plant sites (e.g., Cooper Nuclear Station [Cooper] and Shearon
Harris Nuclear Power Plant [Harris]), undeveloped or restored portions of the nuclear plant site
have been leased for agricultural use including timber production. However, some land areas on
plant sites may not be available for leasing if they are within a nuclear plant’s security zone. Soil
survey maps and data are available for most locations in the United States from the U.S.
Department of Agriculture Natural Resources Conservation Service (USDA 2019).
The geologic resources in the vicinity of each nuclear plant, including rock, mineral, or energy
rights and assets, vary with the location and may support extraction industries. These industries
may include sand and gravel pit operations or quarrying for crushed stone. In general, there is
little if any interaction between plant operations and local extraction industries, although some
nuclear plants may purchase materials for landscaping and site construction from local sources.
Commercial mining, quarrying, or drilling operations are not allowed within nuclear power plant
site boundaries.
Another aspect of the geologic environment is the seismic setting. The NRC has well
established design criteria and standards that are used as the basis for the construction of all
commercial nuclear power plants in the United States. These include ensuring the ability to
withstand environmental hazards, such as earthquakes and flooding. Specifically, the NRC
requires that safety-related structures, systems, and components be designed to take into
account the most severe natural phenomena historically reported for the site and surrounding
area. With regard to earthquakes in particular, existing U.S. nuclear power plants were designed
and built to withstand the ground-shaking level considered appropriate for the location, given the
possible earthquake sources that may affect the site.

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Figure 3.4-1 Occurrence of Prime Farmland and Other Farmland of Importance, with
Nuclear Power Plant Locations Shown. Source: USDA 2021.
U.S. nuclear power plants were originally sited using geologic and seismic criteria set forth in
10 CFR 100.10(c)(1) and 10 CFR Part 100, Appendix A and, where applicable, designed and
constructed in accordance with 10 CFR Part 50, Appendix A. The regulations require that plant
structures, systems, and components important to safety be designed to withstand the effects of
natural phenomena, including earthquakes and other natural phenomena, without loss of
capability to perform safety functions. Plant-specific design bases for seismic protection are
prescribed by a nuclear power plant’s final safety analysis report/updated final safety analysis
report and by applicable technical specifications included in the nuclear plant’s operating
license. Detailed investigations of the proposed site and regional geologic environment are
required to include an analysis of all historic earthquakes with the potential to affect the nuclear
power plant site and power plant operations. Locations for nuclear power plants are also
evaluated and characterized for the presence of geologic faults including those considered to be
capable of generating earthquakes, predicted earthquake ground motions in order to establish
the plant’s safe shutdown earthquake, the potential for the nuclear plant to be exposed to
seismically induced floods and water waves, and for the nature and behavior of the surficial
geologic materials and subsurface materials and their engineering properties. In addition, spent
fuel pools are designed with reinforced concrete so that they may remain operable through the
largest historic earthquake that has or is expected to occur in the area. Similarly, dry storage
casks housed in ISFSIs (see Section 3.1.4.3) have thick metal or steel-reinforced concrete outer
shells and a sealed inner cylinder designed to resist earthquakes and other natural hazards.

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The U.S. Geological Survey (USGS) regularly updates its seismic hazard mapping products
for the United States (see, for example, Rukstales and Petersen 2019; Petersen et al. 2020).
Based on the 2018 seismic hazard maps, and as measured in terms of predicted
earthquake-produced peak horizontal ground accelerations with a 2 percent probability of
exceedance in 50 years (i.e., corresponding to a return time of about 2,500 years), most nuclear
power plants are located in areas with peak horizontal acceleration less than 30 percent of
gravity (0.3 g) (see Figure 3.4-2). Peak horizontal accelerations are related to earthquake
intensity and the magnitude of shaking (Worden et al. 2020). Nuclear power plants subject to a
peak horizontal acceleration of about 0.3 g could experience very strong shaking equivalent to
Modified Mercalli Intensity VII, which indicates damage to buildings of good design and
construction would be expected to be negligible (Rukstales and Petersen 2019; USGS 2021). In
California, one operating nuclear power plant, Diablo Canyon Power Plant (Diablo Canyon), and
one plant undergoing decommissioning (San Onofre Nuclear Generating Station, shut down in
2012) are in locations with predicted peak ground accelerations greater than 40 percent of
gravity based on the 2018 seismic hazard map. Nuclear power plants, including Diablo Canyon,
were designed to safely withstand the seismic hazards associated with earthquakes with
epicenters at various locations and at various depths, magnitudes, and ground accelerations
(AEC 1973; NRC 2020d).

Figure 3.4-2 2018 National Seismic Hazard Model Peak Horizontal Acceleration with a
2 Percent Probability of Exceedance in 50 Years (Site Class B/C) with
Nuclear Power Plant Locations Shown. Seismic Map Source: Rukstales and
Petersen 2019.

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The state of knowledge regarding geologic conditions, site seismology, and seismic hazards at
a specific nuclear power plant site may have changed since construction. Although such
discoveries are expected to be rare, new seismological conditions include the identification of
previously unknown geologic faults. For example, a strike-slip fault was discovered
approximately 1 km (0.6 mi) offshore of the Diablo Canyon Power Plant in 2009 (NRC 2009f).
Moreover, the 2011 Tohoku earthquake and the resulting accident at the Fukushima Dai-ichi
Nuclear Power Plant in Japan prompted a reevaluation of seismic hazards at U.S. nuclear
power plants using present-day NRC requirements and guidance (NRC 2021q). Recent seismic
activity, including the occurrence of induced seismic events (e.g., those generated by fluid
injection associated with oil and gas operations), are monitored and reported by the USGS
(https://www.usgs.gov/programs/earthquake-hazards; USGS 2020). During the environmental
review of a license renewal application and in preparing plant-specific supplemental
environmental impact statements (SEISs) to the LR GEIS, the NRC staff reviews the USGS
earthquake catalog for new and significant information applicable to the description of the
seismic setting of a nuclear power plant site, including the occurrence of induced seismic
events.
Changes in potential seismic hazards and their impact on operating nuclear power plants are
generally not within the scope of the NRC’s license renewal environmental review. Seismic
design issues are considered during plant-specific safety reviews and, more specifically, are
addressed on an ongoing basis through the reactor oversight process and other NRC safety
programs, such as the Generic Issues Program, which are separate from the license renewal
process. When new seismic hazard information becomes available, the NRC evaluates the new
information, through the appropriate program, to determine if any changes are needed at one or
more existing nuclear plants.

3.5

Water Resources

Water resources comprise all forms of surface water and groundwater occurring in the vicinity of
nuclear power plants. Surface water encompasses all waterbodies that occur above the ground
surface, including rivers, streams, lakes, ponds, and other features, such as human-made
reservoirs or other impoundments. Groundwater is water that is below the ground surface within
a zone of saturation, with the uppermost groundwater surface comprising the water table.
Groundwater comprises water that originated naturally as recharge from precipitation (e.g., rain
or the melting of snow, sleet, or hail) or artificially as recharge from activities such as irrigation,
industrial processing, and wastewater disposal. Groundwater returns to the surface through
discharge to springs and baseflow into rivers and streams, evaporation from shallow water table
areas, or human activity involving wells or excavations. Aquifers are subsurface formations
capable of yielding a significant amount of groundwater to wells or springs. Lesser amounts of
groundwater may also occur in areas above the saturated zone in the form of relatively small
and isolated lenses of groundwater known as “perched” groundwater.
Potential water uses, from either surface water or groundwater sources, include uses for
drinking and sanitary purposes, irrigation, maintenance of terrestrial and aquatic resources,
recreation, and, of critical importance to all nuclear plants, industrial cooling, and other
applications. Demands for water are not restricted to freshwater (i.e., generally water with a
TDS level of less than 1,000 mg/L), but can also be met, for certain uses, by brackish (i.e., TDS
level of about 1,000 to 35,000 mg/L) and saltwater (saline) sources, including for industrial
cooling applications. As such, nuclear power plants are located in a range of settings with
respect to water resources availability. Specifically, 11 of the 55 currently licensed nuclear
power plants are located in estuarine or coastal areas, 9 plants are located on or near the

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Great Lakes, and 35 plants are located on rivers and/or with associated impoundments
(e.g., reservoirs) (see also Table 3.1-2 through Table 3.1-4 and Section 3.5.1.1).
Earth’s water is always in movement, and the natural water cycle, also known as the hydrologic
cycle, describes the continuous movement of water on, above, and below the surface of the
Earth. It is the movement of water from surface water, groundwater, and vegetation to the
atmosphere and back to the Earth in the form of precipitation. Natural waters are normally
replenished by precipitation. However, the availability of water resources is being reduced and
their distribution is changing due to human activity and natural forces. This is further aggravated
by global climate change and variations in natural conditions. Impacts within the hydrologic
cycle can be observed in precipitation patterns, infiltration to groundwater, surface runoff,
stream flow, and other natural features.
The water quality of surface waterbodies and groundwater in the vicinity of and within the
watersheds where nuclear power plant sites are located is influenced by a wide range of
activities that are often unrelated to and far removed from plant operations. Urbanization and
development increase the amount of impervious surface coverage, such as roads and
sidewalks, and reduce the natural terrain and pervious surfaces, including woodlands, meadow,
and prairie lands. These alterations result in higher runoff velocities while reducing or
eliminating the ability for infiltration, which also reduces groundwater recharge. Pervious areas
associated with urbanization and development, such as landscape and recreational areas,
contribute to increased surface runoff because they are typically uniformly graded and sparsely
vegetated. Increased runoff is also thermally warmer than precipitation falling on natural terrain
and can carry pollutants entrained from sources of contamination on the land surface and that
may have otherwise been filtered through natural processes. As a result, changes in surface
runoff velocities and volumes have the potential to result in surface water quality impacts,
including changes in the chemical and thermal characteristics of the receiving waters.
Additionally, increases in runoff lead to streamside erosion, loss of topsoil, and other hydrologic
changes leading to increased flooding potential of downstream areas. These changes can occur
in some watersheds despite design guidelines and regulations implemented by local, State,
Tribal, and Federal agencies, as applicable, to manage runoff rates associated with
development.
Typical pollutants carried in stormwater runoff include sediment, nutrients, debris, bacteria, and
common hazardous substances (e.g., fertilizers, pesticides, and petroleum products). Nutrient
additions, whether from fertilizer additions to landscaped lawns in urban and suburban areas or
from croplands in agricultural areas, add to the pollutant loading and can have negative effects
on water quality, terrestrial communities, and aquatic life (see Section 3.6). Atmospheric
deposition of pollutants is also a substantial contributor to water quality degradation in
“downwind” regions and particularly in urbanized areas. Nuclear power plant operations can
contribute to water quality and hydrologic changes by increasing stormwater runoff, adding to
nutrient discharges from sewage treatment, and through effluent discharges from industrial
cooling systems. The additional runoff volume results in a total increase in deposited pollutants
from impervious surfaces and industrial yards. Cooling system discharges typically contain
cooling water treatment chemicals (e.g., corrosion inhibitors and biocides) (see also
Section 3.5.1.2). Such chemical constituents, when released to receiving waterbodies, have the
potential to affect aquatic organisms. Thermal pollution is an additional pollutant that warms a
receiving waterbody through both stormwater runoff and industrial cooling discharges. Within a
watershed, these conditions are exacerbated by basinwide deforestation and stripping of
streamside vegetation in urban, suburban, and agricultural areas.

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The collection of these pollutants from all sources in receiving waters can result in waters that
are unable to meet the water quality standards and desired uses set by States, territories, or
authorized Indian Tribes. The waterbodies that do not meet standards are included in the Clean
Water Act (CWA) 303(d) list as impaired waterbodies and require additional monitoring and
more stringent effluent limits being imposed on industrial and other dischargers under
Section 303(d). Each State is required to submit their impaired and threatened waters list
(i.e., 303(d) list) for EPA approval every 2 years (EPA 2022h). For each water on the list, the
State identifies the pollutant causing the impairment, when known. Based on the NRC’s license
renewal environmental reviews performed since 2013, the range of pollutants identified as
contributing to impairment of adjoining surface waters have included pathogens (e.g., coliform
bacteria), sediment, various nutrients (e.g., phosphorus), polychlorinated biphenyls, and
mercury contamination, none of which were attributable to nuclear power plant operations.
Finally, groundwater quality, whether in shallow, unconfined aquifers comprised of
unconsolidated sediments or bedrock aquifers, may be affected by many of the sources
previously described. Fertilizers, chemicals, and petroleum products can degrade groundwater
quality by infiltration into soil, subsoils, and the water table. Subsurface sources of pollution may
be from broken sewage pipelines, stormwater and/or combined sanitary sewers, as well as
cracks in or failures of underground storage tanks. At nuclear power plant sites, groundwater
quality has been affected by inadvertent releases of radionuclides, predominately tritium, from
plant systems. Spills and leaks of petroleum products from industrial facilities (including nuclear
facilities) also affect groundwater.
Within the context of the information discussed above, the following sections discuss the effects
of past and current nuclear power plant operations on water resources, including relevant
regulatory considerations.
3.5.1

Surface Water Resources

The dominant water requirement at most nuclear power plants is cooling water, which, in most
cases, is obtained from surface waterbodies. For this reason, most plants are located near
suitable supplies of surface water, such as rivers, reservoirs, lakes, the Great Lakes, oceans,
bays, or human-made impoundments, as described above. Such surface water sources also
serve as the receiving water for various wastewater effluents associated with nuclear power
plant operations. One exception is the Palo Verde plant in Arizona, which relies on treated
municipal wastewater for cooling and discharges plant effluent to evaporation ponds. Because
of the interaction between power plants and surface water, issues arise in terms of both usage
and quality. These are discussed in separate sections below.
3.5.1.1

Surface Water Use

Nuclear power plants withdraw large amounts of surface water to meet a variety of plant needs,
especially for condenser cooling (see Section 3.1.3 for detailed analysis). The operating
commercial nuclear power plants considered in this LR GEIS are compared in Table 3.5-1 in
terms of their condenser flow rates, when normalized to energy production. Although nuclear
plants in warmer geographical locations might be expected to have higher water requirements
for cooling, a comparison of the locations of the plants and the normalized water use by their
cooling systems suggests there is no correlation between high water use and warmer climate.
Design factors are likely responsible for the overlapping ranges in condenser flow rates.

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For closed-cycle cooling systems featuring cooling towers, the amount of water consumed
equates approximately to the amount of water lost through evaporation and drift. In this type of
cooling system, the condenser flow rate is much larger than the withdrawal rate from a surface
waterbody, and this withdrawal rate is essentially the water consumption rate of the system. For
once-through cooling systems, the condenser flow rate is nearly equal to the surface water
withdrawal rate, and the consumption rate is much less because water is returned directly to the
surface waterbody and undergoes less evaporative loss than in a cooling tower.
Cooling towers used at operating nuclear power plants consume water at a rate of about 9,400
to 10,000 gallons per minute (gpm) (0.59 to 0.63 cubic meters per second [m3/s]), normalized to
1,000 MWe, as a result of evaporation and drift (Table 3.5-1) (Marston et al. 2018). According to
the National Renewable Energy Laboratory (NREL 2011), the operational water consumption of
nuclear plant cooling towers ranges from 9,700 to 14,000 gpm (0.61 to 0.88 m3/s), normalized to
1,000 MWe. Additional water requirements offset the blowdown returned to the surface
waterbody. Water withdrawal for plants with closed-cycle cooling systems is 5 to 10 percent of
the withdrawal for plants with once-through cooling systems, with much of this water being used
for makeup of water lost to evaporation (NRC 1996). An estimate of typical makeup water needs
for nuclear plants having closed-cycle cooling, normalized to a 1,000 MWe reactor, is about
14,000 to 18,000 gpm (0.9 to 1.1 m3/s) for all makeup needs (NRC 1996). This range of
required makeup water includes not only the consumed water but also the offset of blowdown,
which is returned to the surface waterbody. Variation in water use among plants results from the
design of the cooling tower, concentration factor of recirculated water, climate at the site, plant
operating conditions, and other plant-specific factors.
Once-through cooling systems are somewhat more common than closed-cycle systems
(Table 3.5-1). For once-through systems used at operating nuclear plants, the water withdrawn
is returned to the surface waterbody with less consumptive loss (about 6,600-6,700 gpm or
0.42 m3/s) per 1,000 MWe because there is less evaporation than that associated with cooling
towers (Marston et al. 2018). As indicated by National Renewable Energy Laboratory
(NREL 2011), the operational water consumption of nuclear plant once-through cooling systems
ranges between 2,000 to 7,000 gpm (0.13 to 0.44 m3/s), normalized to 1,000 MWe. Marston
et al. (2018) reports water consumption of once-through cooling systems at operating nuclear
plants as ranging from 5,200 to 8,700 gpm (0.33 to 0.55 m3/s) per 1,000 MWe. In all, the
withdrawal rate from the surface waterbody, however, is much higher in a once-through cooling
system than in a closed-cycle system. For example, in Table 3.5-1, compare the condenser flow
rates needed for once-through systems, which correspond to their surface water withdrawals,
with the consumptive losses of closed-cycle systems (e.g., cooling tower systems), which
correspond to their surface water withdrawal or makeup water requirements. The thermal
discharge from once-through cooling systems is generally higher than that from cooling towers,
as discussed in Section 3.5.1.2.
Additional operational surface-water-related needs at power plants include service water,
auxiliary system supplies, and radioactive waste systems. These needs combined are small
relative to the flow needed for condenser cooling (NRC 1996).
Nuclear plant water usage must comply with State, local, and regional regulations regarding
water supply. Most States require permits regulating surface water usage.

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Table 3.5-1

Comparison of Cooling Water System Attributes for Operating Commercial
Nuclear Power Plants
Number
of
Sites(a)

Condenser Cooling
Water Flow per Unit
in gpm(b)

Average Reported
Consumptive Water Loss
per 1,000 MWe in gpm

Pond and/or canal

9

454,000 to 907,000

10,200(c)

Mechanical draft cooling tower

7

98,000 to 660,000

10,000(d)

Natural draft cooling tower

13

410,000 to 836,000

9,400(d)

Once-through cooling (only)

24

340,000 to 1,200,000

6,700(d)

Once-through cooling with tower

4

292,000 to 750,000

6,600(d)

Cooling System(a)

gpm = gallons per minute; MWe = megawatts-electric.
(a) There are 54 operating commercial power reactor sites (2023) encompassing 92 nuclear generating units. For
cases of multiple reactors per site, reactors using the same type of cooling system were counted only once. If
multiple reactors at a site used different cooling systems (i.e., Nine Mile Point plant and Arkansas plant), they
were tallied separately.
(b) Source: Appendix C of this LR GEIS.
(c) Source: National Renewable Energy Laboratory 2011 (NREL 2011).
(d) Source: Marston et al. 2018. Data for some plants were not reported by Marston et al. 2018.
Note: To convert gallons per minute (gpm) to liters per minute, multiply by 3.784. To convert gpm to cubic meters
per second (m3/s), multiply by 0.000063.

For nuclear plants relying on river water, consumptive water losses reduce surface water
supplies for other users downstream. In areas experiencing water availability problems, nuclear
power plant consumption could conflict with other existing or potential uses (e.g., municipal and
agricultural water withdrawals) and instream uses (e.g., adequate instream flows to protect
aquatic biota, recreation, and riparian communities). Water availability issues have not been
generally noted in past license renewal environmental reviews and are most likely to occur
during times of extended drought.
Both water availability and water temperature are important factors in maintaining operations at
power plants. As was previously described in the 2013 LR GEIS, in August 2007, a heat wave
resulted in high river water temperatures at the Browns Ferry plant in Alabama. Because of the
reduced capability of the river water to cool the condensers, one of the plant’s three reactors
was shut down, while operations at its other two reactors were cut by 25 percent. In summer
2006, the Quad Cities Nuclear Power Station (Quad Cities) in Illinois had to reduce operations
because the Mississippi River was warm, and other plants in Illinois and Minnesota had to cut
back as a result of drought effects.
More recently, a number of nuclear power plants have been affected by reduced water
availability due to high temperatures. As relevant examples, in July 2012, Byron Station (Byron)
Units 1 and 2 had to reduce power due to degraded cooling tower performance during hot
weather (NRC 2021o). In August 2014, Turkey Point Units 3 and 4 had to operate at reduced
power due to excessive ultimate heat sink temperature (i.e., in the CCS) (NRC 2021m). In
July 2016, the Perry Nuclear Power Plant (Perry) had to reduce power due to high ambient
water temperature (NRC 2021p). In August 2018, the Clinton plant was forced to reduce power
due to discharge temperature limitations (NRC 2021n).
In the report, Water-Related Power Plant Curtailments: An Overview of Incidents and
Contributing Factors, National Renewable Energy Laboratory (NREL 2016) identifies 25
incidents at nuclear power plants between 2000 and 2015 where high water temperatures or
water availability affected power generation. The operating nuclear power plants cited included

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Duane Arnold Energy Center, Prairie Island Nuclear Generating Plant (Prairie Island), LaSalle
County Station (LaSalle), Dresden, Perry, Donald C. Cook Nuclear Plant (D.C. Cook), Quad
Cities, Braidwood Station (Braidwood), Limerick Generating Station (Limerick), Vermont Yankee
Nuclear Power Station (Vermont Yankee), Pilgrim Nuclear Power Station (Pilgrim), Millstone
Power Station (Millstone), Oyster Creek Nuclear Generation Station (Oyster Creek),
Hope Creek, River Bend Station (River Bend), Browns Ferry, Turkey Point, and Monticello.
3.5.1.2

Surface Water Quality

Discharges from the circulating cooling water system account for the largest volumes of water
and usually the greatest potential impacts on water quality and aquatic systems, although other
systems may also contribute heat and chemical contaminants to the effluent. Provisions of the
CWA regulate the discharge of pollutants into waters of the United States.
To operate a nuclear power plant, NRC licensees must comply with the CWA, including
associated requirements imposed by EPA or the State. Specifically, Section 402 of the CWA
requires that all facilities that discharge pollutants from any point source into waters of the
United States obtain a NPDES permit. A NPDES permit is developed with two levels of controls:
technology-based limits and water quality-based limits. NPDES permit terms may not exceed
5 years, and the applicant must reapply at least 180 days prior to the permit expiration date
(EPA 2022g). Expired NPDES permits may be administratively extended and remain valid and
in-force if the permit holder submits a complete NPDES renewal application as required. The
EPA is authorized under the CWA to directly implement the NPDES program; however, the EPA
has authorized most States and Tribes to implement all or parts of the national program.
Conditions of discharge for each nuclear power plant are specified in its NPDES permit issued
by the State or EPA.
Section 401 of the CWA requires that any applicant for a Federal license or permit to conduct
any activity which may result in any discharge into navigable waters must provide the Federal
licensing or permitting agency with a certification from the State or appropriate water pollution
control agency in which the discharge originates or will originate. This water quality certification
implies that discharges from the activity or project to be licensed or permitted will comply with
CWA requirements, as applicable, including that the discharge will not cause or contribute to a
violation of applicable water quality standards. If the applicant has not received Section 401
certification, the NRC cannot issue a license or permit unless the certifying authority has waived
the requirement.
In July 2020, the EPA published a final rule revising the procedural requirements for CWA
Section 401 certifications at 40 CFR 121 (85 FR 42210). The final rule became effective on
September 11, 2020. In 2021, the EPA initiated a process to reconsider and revise the 2020
CWA Section 401 Certification Rule (86 FR 29541). A final rule was issued in September 2023
(88 FR 66558). To initiate the certification process, Federal license or permit applicants must
submit a “request for certification” to the appropriate certifying authority (i.e., State, territory,
authorized Tribe, or EPA) (40 CFR 121.5). The revised regulations at 40 CFR 121.6 require, in
part, that the certifying authority provide a written confirmation to the project proponent
(applicant) and Federal agency of the date that the request for certification was received. The
“reasonable period of time” for the certifying authority to act on the request for certification may
not exceed one year from the date that the request for certification was received. The final rule
also imposes revised requirements for Federal agencies under the “neighboring jurisdictions
process,” specified in 40 CFR Part 121, Subpart B. The Federal agency may not issue a license
or permit prior to concluding the neighboring jurisdictions process. However, the certifying

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authority’s failure or refusal to act on a certification request within the reasonable period of time
is considered a waiver, provided the Federal agency promptly notifies the certifying authority
and project proponent (applicants), as specified in 40 CFR 121.9. The NRC further recognizes
that some NPDES-delegated States explicitly integrate their Section 401 certification process
with NPDES permit renewal and issuance.
Separate from permitting and associated regulatory requirements imposed on operating nuclear
plants, the NRC considers new information and aspects of plant operations that could interact
with the environment in a manner not previously recognized during the course of license
renewal environmental reviews conducted for initial LRs and SLRs. For example, nuclear power
plants with cooling ponds located in coastal areas have the potential to affect the water quality
of adjacent waterbodies via the groundwater pathway. This new, plant-specific aspect of
continued operations was discovered during review of the second license renewal of
Turkey Point Units 3 and 4 (NRC 2019c).
Clean Water Act
• Section 402 authorizes the NPDES permit program that controls water pollution by
regulating point sources, including cooling water discharge from all facilities including
thermoelectric power plants that discharge pollutants into waters of the United States.
• Section 401 requires applicants for Federal licenses or permits to conduct any activity which
may result in any discharge into navigable waters5 to obtain a certification that their activities
will not violate State water quality standards.
• Section 316(a) addresses the adverse environmental impacts associated with thermal
discharges into waters of the United States. Under 316(b), the NPDES permitting authority
can impose alternative, less-stringent, facility-specific effluent limits (called “variances”) on
the thermal component of individual point source discharges as long as the variances will
assure the protection and propagation of a balanced, indigenous population of shellfish, fish,
and wildlife in and on the receiving body of water. Variances are good for the term of the
NPDES permit (5 years), and the facility licensee must reapply for the variance each permit
renewal term.
• Section 316(b) requires that the location, design, construction, and capacity of cooling water
intake structures reflect the best technology available (BTA) for minimizing impingement
mortality and entrainment of aquatic organisms. Impingement mortality BTA compliance
options are prescribed in regulations, while entrainment BTA is site-specific.
3.5.1.2.1 Thermal Effluents and Withdrawal of Cooling Water from Surface Waterbodies
NPDES permits for nuclear power plants impose temperature limits for effluents (which may
vary by season) and/or a maximum temperature increase above the ambient water temperature
(referred to as “delta-T,” which also may vary by season). Other aspects of the permit may
include the compliance measuring location and restrictions against plant shutdowns during
winter to avoid drastic temperature changes in surface waterbodies. Some NPDES permits also
require nuclear power plants that operate a once-through cooling system with helper cooling
towers to use the cooling towers seasonally to reduce thermal load to the receiving waterbody.
5

For purposes of the Clean Water Act (33 U.S.C. 1251 et seq.) and its implementing regulations, the U.S.
Environmental Protection Agency’s (EPA’s) regulations in 40 CFR Part 120 establish the scope of the
terms “waters of the United States” and “navigable waters.”

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The area affected by heated releases to surface waterbodies (the thermal plume) varies with
site-specific conditions (e.g., discharge temperature, discharge rate, discharge structure location
and design, flow of the surface waterbody, and temperature of the surface waterbody). Thermal
plumes may be assessed in the field through computer modeling using thermal field data.
Generally, the use of cooling towers decreases the thermal effluent discharged by a nuclear
power plant (e.g., NRC 2006d).
Sections 316(a) and 316(b) of the CWA address thermal effects and impingement mortality and
entrainment of aquatic organisms caused by operation of nuclear power plant cooling systems
that withdraw and discharge to regulated waterbodies. The EPA, or authorized States and
Tribes, impose the requirements of these CWA sections through NPDES permitting programs.
Under CWA Section 316(a), nuclear power plants may apply for a thermal variance from State
thermal surface water quality criteria. To do so, the facility must demonstrate that the requested
variance is more stringent than necessary to assure the protection and propagation of a
balanced, indigenous population of shellfish, fish, and wildlife in and on the receiving body of
water (40 CFR Part 125 Subpart H). Variances are good for the NPDES permit term (5 years),
and the licensee must reapply for the variance each permit renewal term. CWA Section 316(b)
requires that the location, design, construction, and capacity of cooling water intake structures
reflect the BTA for minimizing impingement mortality and entrainment of aquatic organisms.
Impingement mortality BTA compliance options are prescribed in regulations, while entrainment
BTA is plant-specific in application. Section 4.6.1.2 describes these sections of the CWA in
detail, including the regulatory requirements relevant to nuclear power plants.
3.5.1.2.2 Other Effluents
Liquids containing chemicals and other constituents are discharged to surface water from
nuclear power plants, as discussed in Section 3.1.4.1 and 3.1.5. The concentrations and flow
rates of the liquids vary with activities involving the systems associated with floor drains,
blowdown, laundries, decontamination, and other facilities. The liquids may also undergo
treatment before reuse or discharge. These effluents are regulated under the plant’s NPDES
permit. As part of the permitting process, concentration limits are established, and monitoring
takes place at specific outfalls or other monitoring locations. The frequency of sampling is also
covered by the plant’s NPDES permit. The EPA or authorized State or Tribal agencies also
provide the reporting requirements, and they may post results on a publicly accessible website.
Noncompliance issues may range from administrative matters to exceedances of concentration,
temperature, or flow limits. The exceedance of a parameter limit will trigger the permitting
agency to review the history and magnitude of exceedance recurrences. Actions may include
reviewing the permit for appropriate parameter levels, setting a compliance schedule for the
applicant, assessing fines, and, in a worst-case scenario, withdrawing a permit and disallowing
the legal ability to discharge.
Sanitary sewage wastes are treated before their release to the environment to minimize
environmental impacts. The treatment may be through discharge to a municipal wastewater
treatment system, an onsite wastewater treatment plant, or an onsite septic system. In cases
where nonradioactive sanitary or other wastes cannot be processed by onsite wastewater
treatment systems, the wastes are collected by independent contractors and trucked to offsite
treatment facilities. Waste collection and offsite disposal can occur during a planned outage,
when portable toilets may be required to accommodate the additional workforce. Water quality
issues related to sanitary waste treatment include the adequacy of the wastewater treatment
system capacity for handling the increased flow and loading associated with operational
changes to the plant, emission of phosphates from onsite laundries, suspended solids, coliform

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bacteria from sewage treatment discharges, and other effluents that cause excessive
biochemical oxygen demand. State regulators are typically involved in site inspections, review of
monitoring reports, and the handling of any violations.
The control of biological pests is critical to maintaining optimum system performance and
minimizing operating costs. Consequently, many nuclear power plant cooling systems are
periodically treated with molluscides to control the Asiatic clam (Corbicula fluminea) and the
zebra mussel (Dreissena polymorpha), which are generally found in the portions of the cooling
system where water temperatures are ambient rather than heated.
Biocides also are commonly used in cooling towers, although they may also be used in
once-through systems or cooling ponds (DOE 1997a). Discharge of these chemicals to the
receiving body of water can have toxic effects on aquatic organisms. Chlorine is commonly used
as a biocide at nuclear power plants and represents the largest potential source of chemically
toxic release to the aquatic environment. It may be injected at the intake or targeted at various
points (such as the condensers) on an intermittent or continuous basis. Chlorine gas, which was
commonly used in the past, has been replaced by many users with other forms, such as bleach
(sodium hypochlorite) (DOE 1997a). At some plants, chemical biocides may be augmented with
a non-chemical cleaning system that involves the injection of small spheres to control biofouling
and buildup in condenser tubing. The spheres are injected into the water system and then
collected upon discharge for reuse.
Bromide compounds have been used increasingly in recent years, either in place of or in
addition to chlorine treatments. Dechlorination may occur prior to discharge. Non-oxidizing
biocides used to control zebra mussels and other organisms include quaternary ammonia salts,
triazine, glutaraldehyde, and other organic compounds.
Most nuclear power plants have a stormwater pollution prevention plan, with the parameter
limits of the stormwater outfalls included in either an NPDES general permit or individual
NPDES permit. Plants may also have a spill prevention, control, and countermeasures plan that
contains information about potential liquid spill hazards and the appropriate absorbent materials
to use if a spill occurs.
3.5.1.3

Hydrologic Changes and Flooding

As described in Section 3.5, urbanization of watersheds in which nuclear power plants operate
increases the amount of impervious surface coverage resulting in water quality impacts and
changes in the hydrologic characteristics of the watershed. Urbanization has a direct correlation
to the degradation of natural receiving streams. The higher the percentage of the impervious
surface coverage in a watershed, the higher the flow velocity and volume in receiving
waterbodies. The loss of wetlands, marshes, and riparian habitat in an urbanized watershed
exacerbates hydrologic changes and the potential for flooding (see Section 3.6.1.2). Increases
in stream flow erode natural stream banks and scour natural vegetation from littoral zones, while
also adding to higher flow volume and increased potential for flooding. A flood is the occurrence
when, under high water level and/or flow conditions, water overflows the natural or artificial bank
of the waterbody. The floodplain or zone defines the extent of the land areas covered by the
overflowing water. Floods can occur at any time, but weather patterns, terrain, land use
coverage, and other factors influence when and where floods happen, as well as their frequency
and severity. For example, the western United States can experience flooding due to cyclones
in the winter and early spring; the streams in the southwest United States can experience flash
flooding due to thunderstorms in late summer and fall; frontal storms in the northern and eastern

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United States can cause floods during the winter and spring; and the southeastern
United States experiences flooding due to tropical storms, such as hurricanes, during the late
summer and fall.
Flood zone boundaries are determined based on the predicted recurrence interval of flooding
and the extent of the land area inundated through the use of analytical modeling and field
observations. The recurrence interval is the average number of years between floods of a
certain size. For instance, the 100-year flood, on average, is expected to occur once every
100 years. However, statistically there is a 1 in 100 chance that the 100-year flood will occur in
any given year.
Flood zones are dynamic and change over time due to natural forces. Further, changes in
urbanization increase runoff and changes in weather patterns increase the intensity of
precipitation events. In some instances, land areas that were not previously within a flood zone
have been reclassified as being in one after nearby river elevations and flood potential were
reanalyzed. On large rivers, dams have been shown to reduce flooding. Flood-control dams,
such as on multiuse reservoirs, are designed to release water flow at a controlled rate and allow
water to back up in a reservoir when, typically under storm events, the inflows exceed the
predetermined outflow rate. This prevents high flows from reaching streams that would
otherwise flood and allows water flow to bypass communities without flooding them.
Currently operating nuclear power plants were originally sited in consideration of the hydrologic
siting criteria set forth in 10 CFR Part 100 and designed and constructed in accordance with
10 CFR Part 50, Appendix A. The regulations require that plant structures, systems, and
components important to safety be designed to withstand the effects of natural phenomena,
including flooding, without loss of capability to perform safety functions. Plant-specific design
bases for flood protection are prescribed by a nuclear power plant’s updated safety analysis
report and by applicable technical specifications. Acceptable protection for floods includes
levees, seawalls, floodwalls, or breakwaters. If new information or plant operating experience
related to flooding becomes available, the NRC evaluates the new information or plant data to
determine whether any changes are needed at existing plants. Flood protection issues are
considered during plant-specific safety reviews and, more specifically, are addressed on an
ongoing basis through the reactor oversight process and other NRC safety programs, which are
separate from the license renewal process.
3.5.2

Groundwater Resources

Groundwater is used as a secondary source of water at many nuclear power plants. Onsite
groundwater may be extracted through wells and delivered to the point of use after appropriate
treatment. At some nuclear plants, licensees must manage high water tables through pumping
or drainage systems. Nuclear power plants produce liquid radioactive effluents (Section 3.1.4.1),
other wastewater streams (Section 3.5.1.2.2), and use and store other substances
(e.g., petroleum products) that have the potential to contaminate soils, surface water runoff, and
underlying groundwater.
3.5.2.1

Groundwater Use

Some nuclear power plants also use groundwater as a source of water for some of their
operational needs (e.g., NRC 2013b, 2014f, 2018c, 2020f) (see also Section G.1.1.2,
Appendix G). The rate of usage varies greatly among the plants. Many plants use groundwater
primarily for the potable water system and require less than 100 gpm (378 liters per minute or

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0.006 m3/s) (e.g., NRC 2015c). At some plants, the original construction required dewatering of
a shallow aquifer by using pumping wells or a drain system. At some nuclear plants, dewatering
systems are operated and maintained to lower the water table near buildings or to provide
hydraulic containment of contaminated groundwater (e.g., NRC 2015b). Groundwater wells may
also be operated to extract contaminated groundwater from an aquifer (e.g., NRC 2018c,
2019c). This may be accomplished either by pumping wells, sumps, drains along foundations,
and other methods. Groundwater may also be used for sanitary uses or other minor
miscellaneous uses such as for equipment washing (NRC 2020g). Groundwater may undergo
processing to be used for plant makeup or service water systems. Groundwater usage
regulations vary considerably from State to State, and State allocation permits are typically
required.
At the Grand Gulf plant in Mississippi, large-diameter wells with radial collector arms (i.e.,
Ranney wells) are used to withdraw groundwater along the Mississippi River at relatively high
rates. Radial collector wells are installed in alluvial aquifers along rivers to obtain a mixture of
groundwater and surface water through induced infiltration. At Grand Gulf, the average
groundwater pumping rate by their well system is approximately 27,900 gpm (1.76 m3/s)
(NRC 2014e). Groundwater withdrawn at Grand Gulf is used for cooling, makeup, service,
potable, sanitary, landscaping, and fire protection.
3.5.2.2

Groundwater Quality

The quality of groundwater may be affected by operations at nuclear power plants. Water from
cooling ponds may seep into the underlying surficial aquifer. Activities at power plants typically
include general industrial practices, such as the storage and use of hydrocarbon fuels (diesel
and/or gasoline), solvents, and other chemicals. These practices have the potential to
contaminate soil and groundwater, and, at some plants, such contamination has occurred.
Examples from plant-specific SEISs include leakages or spills of gasoline (with methyl tertiary
butyl ether or MTBE) at fuel tank storage areas, spills of fuel at transfer or filling stations, solvent
leakages from storage area drums, spilled or sprayed solvents, and underground line leaks of
hydraulic oil or diesel fuel (e.g., NRC 2006d, NRC 2007b, NRC 2016c). These incidents
involved regulatory oversight under State regulations for hydrocarbons and under RCRA
(42 U.S.C. § 6901 et seq.) for other chemicals, and offsite groundwater users were not affected.
Radionuclide releases from nuclear power plants have been identified as the source of
radioactive materials in groundwater (or below-ground moisture) at many plant sites. These
releases have been attributed to system leaks (e.g., from pipes, valves, or tanks), evaporation
of liquids, condensation of vapors, and normal operations (routine, approved releases)
(NRC 2021k). Detection of tritium has generally been the initial indicator of a release because it
travels readily in groundwater. The issue of tritium (and other radionuclide) releases to
groundwater rose to prominence as groundwater contamination was observed at an increasing
number of plants, including the exceedance of drinking water standards in onsite groundwater at
some plants.
The NRC formed a task force in 2006 in response to incidents at the Braidwood, Indian Point
Energy Center (Indian Point), Byron, and Dresden plants to examine the matter of liquid
radionuclide releases from power plants (NRC 2006e). The task force report noted that the
leaks were generally not observable because they occurred underground and because plants
were not required to have onsite groundwater monitoring wells unless an onsite well was used
for drinking water or irrigation water. The task force concluded that the available data on
radionuclide releases did not identify any public health impacts, but the level of public concern

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warranted recommendations for enhanced regulations or regulatory guidance for unplanned,
unmonitored releases; additional decommissioning funding and license renewal reviews; and
enhanced public communications (NRC 2006e).
In response to the discoveries of underground radionuclide releases at nuclear power plants,
the Nuclear Energy Institute, which represents the nuclear industry on policy issues, developed
the Groundwater Protection Initiative, originally published in 2007 and revised most recently in
2019 (NEI 2019). Each Nuclear Energy Institute member company voluntarily committed to
develop and implement a plant-specific groundwater protection program for operating or
decommissioning nuclear power plants by July 31, 2006. These programs cover the
assessment of plant systems and components, site hydrogeology, and implementation of
groundwater monitoring programs. To monitor the actions of the nuclear industry, the NRC
updated its inspection procedure to include this issue as part of its routine radiological
inspection at all nuclear power plants.
In March 2010, the NRC formed a Groundwater Task Force to determine whether additional
actions were needed to strengthen the NRC’s response to incidents of radionuclide releases to
groundwater at nuclear power plant sites (NRC 2010e). This new task force was comprised of
NRC management and technical staff charged with reevaluating the recommendations made in
the 2006 lessons learned report and to consider more recent tritium releases to groundwater
from nuclear power plants. On June 11, 2010, the task force issued its report that identified
16 conclusions and 4 recommendations (NRC 2010b).
Subsequently, the NRC’s Executive Director for Operations appointed a senior management
review group to consider the Groundwater Task Force’s final report, identify the policy issues
associated with the NRC’s groundwater protection regulatory framework, develop options for
addressing the policy issues, and present options to the Commission (NRC 2010c). The
outcome of the appointed senior management group’s review of the Groundwater Task Force
Final Report was issued in February 2011 via SECY-11-0019 (NRC 2011d) along with a
separate memorandum to the NRC Chairman. In summary, the group supported several
ongoing staff actions, including evaluations of the long-term effectiveness of industry
groundwater protection initiatives through onsite inspections, review of licensees’ root cause
analyses, tracking of the frequency of leakage, and evaluation of industry performance metrics
related to leakage and potential groundwater contamination.
In SRM-SECY-11-0019, dated August 15, 2011 (NRC 2011f), the Commission approved the
senior management review group’s recommendation to not incorporate the industry’s voluntary
initiative on groundwater protection into the NRC’s regulatory framework and that the staff
continue to monitor the effectiveness of the industry initiatives. The Commission also requested
that the staff provide options for revising the agency’s approach to groundwater protection.
On March 29, 2012, the staff submitted an options paper regarding the NRC’s approach to
groundwater protection (SECY-12-0046) to the Commission (NRC 2012f). The staff
recommended an option that included continuing the agency’s established regulatory approach
under which the staff would continue inspecting and enforcing existing regulations using the
system of dose limits and as low as is reasonably achievable (ALARA) principles. The staff
would also implement the new regulatory requirements in 10 CFR 20.1406 for minimizing the
introduction of residual radioactivity into the plant site and in 10 CFR 20.1501 for performing
subsurface (i.e., soil and groundwater) monitoring.

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The Commission in SRM-SECY-12-0046, approved the staff’s recommended option to continue
the current regulatory approach to groundwater protection, including the additional requirements
contained in the decommissioning planning rule. The Commission also directed the staff to
provide a notation vote paper based on the result of comments solicited on the technical basis
including the pros and cons of moving forward with a proposed prompt remediation rulemaking
under consideration by the staff (NRC 2012h).
The NRC staff conducted a public meeting and webinar on June 4, 2013, to obtain stakeholder
comments on the ongoing prompt remediation issue. In SECY-13-0108, dated October 7, 2013,
the staff reported the results of its evaluation of stakeholder comments to the Commission
(NRC 2013c). In SRM-SECY-13-0108, the Commission approved the NRC staff’s
recommendation to collect 2 years of additional data from the implementation of the
decommissioning planning rule.6 Based on the staff’s completion and evaluation of the data and
stakeholder engagement, the Commission directed that the staff provide a paper with
recommendations for addressing remediation of residual radioactivity at licensed facilities during
facility operations (NRC 2013d).
In SECY-16-0121, dated October 16, 2016, the staff provided the Commission with its
evaluation of options including the consideration of rulemaking to address the remediation of
residual radioactivity at licensed facilities during operations (i.e., prompt remediation). The staff
recommended no rulemaking and cited existing NRC regulatory requirements and voluntary
industry initiatives as providing adequate protection for public health and safety (NRC 2016e). In
December 2016 (SRM-SECY-16-0121), the Commission approved the staff’s recommended
option (NRC 2016g).
The NRC has repeatedly determined that inadvertent releases at nuclear power plant sites
either remain on power plant property or involve such low offsite levels of tritium that they do not
affect public health and safety. The NRC has continued to review incidents of inadvertent
releases to ensure that nuclear power plant operators take appropriate action.
Additionally, the NRC maintains an updated list of operating reactor sites that have experienced
a leak or spill of liquids containing radioactive material to the onsite licensee (owner)-controlled
area. The list includes plant sites where the concentration of tritium in the leak source, or in a
groundwater sample, exceeded the EPA drinking water standard (20,000 pCi/L) at some time
since initial startup (NRC 2021j, NRC 2023g). To date, tritium in excess of the drinking water
standard has been observed in groundwater at 37 currently operating nuclear power plant sites
as a result of leaks or spills, with 6 plants continuing to have tritium in groundwater above the
drinking water standard as of October 2023. No site has reported tritium above the drinking
water standard in offsite groundwater (NRC 2021j, NRC 2023g).
The NRC provides public access to all radioactive effluent and environmental monitoring data,
including industry groundwater protection initiative monitoring results, reported to the NRC by
nuclear power plant licensees at https://www.nrc.gov/reactors/operating/opsexperience/tritium/plant-info.html.
6

The NRC has determined that for nuclear power plant licensees whose license applications were
submitted prior to August 21, 1997, existing radiological environmental monitoring programs and
subsurface (groundwater) monitoring conducted by implementation of Nuclear Energy Institute 07-07,
“Industry Ground Water Protection Initiative—Final Guidance Document” (issued August 2007), are
generally considered adequate to meet the Decommissioning Planning Rule (10 CFR 20.1406,
“Minimization of Contamination,” and 10 CFR 20.1501, “General” relating to surveys and monitoring
(NRC 2012j).

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In summary, to protect groundwater quality during the period of operations and to minimize
contamination during decommissioning, NRC licensees are required to conduct operations to
minimize the introduction of residual radioactivity into the site, including the subsurface. NRC
licensees are also required to survey, evaluate, document, and report the hazard of known spills
or leaks of radioactive material. The NRC has reporting requirements based on the amount of
radioactivity released, thus any large spills or leaks will be reported.

3.6

Ecological Resources

A variety of ecological resources exist at and in the vicinity of operating nuclear power plants
across the United States. This section presents an overview of those resources. Sections 3.6.1,
3.6.2, and 3.6.3 discuss terrestrial resources, aquatic resources, and federally protected
ecological resources, respectively. Wetlands and floodplains, which are transitional areas
between terrestrial and aquatic systems, are described with terrestrial resources. This section
summarizes the effects of past activities, including construction and current operations, at
operating commercial nuclear power plant sites.
3.6.1

Terrestrial Resources

Operating commercial nuclear power plants are located in a variety of terrestrial habitat types.
For the purposes of this analysis, terrestrial ecological resources in the vicinity of nuclear power
plants are described in terms of upland vegetation and habitats, floodplain and wetland
vegetation and habitats, and wildlife. Section 3.6.3.1 discusses federally protected terrestrial
resources.
3.6.1.1

Upland Vegetation and Habitats

Terrestrial vegetation and habitats include forests, grasslands, and shrublands. These habitats
have been affected by the initial construction of nuclear power plants, operation of those plants,
and natural successional changes occurring within vegetation communities. In general, the level
of land management varies by land use type at a nuclear power plant. See Section 3.2.1 for a
general description of land use at a nuclear power plant.
Impacts on terrestrial vegetation and habitats can result from several activities or processes
during normal operations at a nuclear power plant. Since startup of operations, industrial-use
portions of nuclear power plant sites have typically been maintained as modified landscapes.
These areas may also include disturbed early successional habitats or areas of relatively
undisturbed habitat. Site maintenance, such as mowing and herbicide or pesticide application,
generally keeps the diversity of plant species at a reduced level in these areas. Native plant
species are often replaced by cultivated varieties or weedy species tolerant of disturbance.
Non-industrial use portions of nuclear power plant sites may include natural areas, such as
forest or shrubland, in various degrees of disturbance.
Terrestrial habitats near nuclear power plants can be subject to radiological releases under
normal plant operations. These habitats are exposed to small amounts of radionuclides that
result from the deposition of particulates released from nuclear power plant vents during normal
operations. Releases typically include noble gases (which are not deposited), tritium, isotopes of
iodine, and cesium and they may also include carbon-14, strontium, cobalt, and chromium.
Exposure to these radionuclides results in a dose rate to terrestrial plants of much less than
1.0 rad/d (0.1 Gray (Gy)/d), which is the U.S. Department of Energy (DOE) guideline for
adequate protection of terrestrial plant populations from the effects of ionizing radiation

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(DOE 2019) (see Section 4.6.1.1.2). Radionuclides, such as tritium, and other constituents in
cooling water systems, such as biocides, that enter shallow groundwater from cooling ponds
can be taken up by terrestrial plants.
Terrestrial habitats near nuclear power plants that have cooling towers are subject to the
deposition of cooling tower drift particulates (including salt); the deposition of water droplets on
vegetation from drift; structural damage from freezing vapor plumes; and increased humidity.
Small amounts of particulates from cooling towers are dispersed over a wide area. Particulates
from natural draft towers are typically dispersed over a larger area and at a lower deposition
rate than those from mechanical draft towers (Roffman and Van Vleck 1974). However, most of
the deposition from cooling towers occurs in relatively close proximity to the towers. Generally,
deposition rates are below those that are known to result in measurable adverse effects on
plants, and no deposition effects on agricultural crops or natural vegetative communities have
been observed at most nuclear power plants. Some exceptions were observed at nuclear power
plants in studies conducted in the 1980s (e.g., Palisades Nuclear Plant [Palisades] in Michigan
and Prairie Island in Minnesota; NRC 1996); however, the NRC staff’s review of recent license
renewals did not identify any new issues. Impacts from icing, when they have occurred, have
been minor and localized near cooling towers.
Effects of nuclear power plant operations on terrestrial habitats also include the effects of
transmission line ROWs and their maintenance. ROW management typically includes the
periodic cutting and removal of tall woody vegetation and the application of herbicides. Use of
mechanized equipment can crush vegetation or injure or disturb insects and small animals.
However, transmission lines and associated structures within the scope of license renewal
reviews are expected to occur primarily on developed portions of sites and would include only
the short lengths of transmission lines that run from the plant to the nearest substation (see
Section 3.1.7).
3.6.1.2

Floodplain and Wetland Vegetation and Habitats

Floodplains are areas where the land is susceptible to flooding from any source and tend to
occur along rivers and coastlines near many nuclear power plants (FEMA 2022a). These areas
attenuate the extent of flooding and often include wetlands, marshes, and riparian habitat. A
100-year floodplain typically has at least a 1 percent chance of flooding in any given year. Many
nuclear power plant cooling water intake systems and outfalls lie within floodplains. Some
transmission lines may also cross through floodplains. Executive Order 11988, “Floodplain
Management” (42 FR 26951), requires Federal agencies to restore and preserve the natural
and beneficial values served by floodplains for activities undertaken in such areas. Communities
participating in the National Flood Insurance Program (NFIP) implement local floodplain
management regulations, and Federal Emergency Management Agency maintains a list of
communities participating in the NFIP (FEMA 2022b). In some jurisdictions, local floodplain
regulations may have more restrictive standards than the minimum standards in the NFIP.
Nuclear power plant activities during the license renewal term that occur in or have the potential
to affect floodplains would need to comply with local floodplain regulations.
Many wetland types occur near nuclear power plants. These include riverine, palustrine,
lacustrine, estuarine, and marine wetlands, as described by the U.S. Fish and Wildlife Service
(FWS) Cowardin classification for the National Wetlands Inventory (Cowardin et al. 1979). Most
nuclear power plants have wetlands nearby (within a radius of 5 mi [8 km]), and wetlands cover
an average of 9.3 percent of the land area near operating nuclear power plants, as mapped by
the National Wetlands Inventory (FWS 2022b). The definition of wetlands traditionally excludes

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deep-water habitats, which are permanently flooded areas (Cowardin et al. 1979; FGDC 2013)
and which occupy, on average, 21.2 percent of the area within 5 mi of operating nuclear power
plants. The percentage of wetlands and deep-water habitats within 5 mi (8 km) of nuclear power
plants is presented in Table G.6-3 in Appendix G.
Wetland Types That Occur near Nuclear Power Plants
• Riverine wetlands are contained within a channel that has moving water, at least
periodically, and lack persistent vegetation.
• Palustrine wetlands are freshwater habitats that primarily support trees, shrubs, or persistent
emergent plants, or they can be small (generally under 20 ac or 8 ha), shallow wetlands
lacking such plant communities.
• Lacustrine wetlands are large or deep bodies of water that lack persistent vegetation.
• Estuarine wetlands occur near land with access to the ocean, are influenced by tides, and
are diluted to a variable extent by freshwater.
• Marine wetlands are exposed to open ocean waves and currents and may be slightly diluted
by freshwater.
Source: Cowardin et al. 1979.

At many nuclear power plant sites, initial plant construction and various aspects of plant
operation have affected wetlands. These effects include those associated with facility
construction, transmission line construction and maintenance, construction and operation of
cooling systems, and stormwater management. Effects on wetlands from construction activities
and stormwater runoff often include changes in vegetative plant community characteristics,
altered hydrology, decreased water quality, and sedimentation (Wright et al. 2006; EPA 1996).
Forested wetlands in ROWs are converted to scrub/shrub or emergent wetland types when
trees are removed, and ROW management programs maintain ROWs in these habitat types.
The operation of heavy equipment in wetlands during ROW maintenance or transmission line
repairs can damage or compact wetland soils and vegetation and may promote the
establishment of invasive species (DOE 2000). Executive Order 13112, “Invasive Species”
(64 FR 6183), directs Federal agencies to prevent introduction of or to monitor and control
invasive species.
Wetland losses or alterations occurred during the construction of many nuclear power plants.
For example, during construction of the Oyster Creek plant (no longer operating) in New Jersey,
the South Branch of Forked River and Oyster Creek were dredged and widened to
accommodate operation of the cooling water system. As a result, most of the natural aquatic
habitats that occurred within these portions of the river and creek were destroyed (NRC 2007b).
Construction resulted in the loss of 200 ac (80 ha) of several types of wetlands (AEC 1974b),
and the resulting ecology of the river and creek is that they now function similar to Barnegat
Bay. However, at nuclear power plants using cooling ponds, new wetland habitats may form
along the margins of those ponds.
The operation of cooling water systems can expose wetland habitats to thermal impacts and
contaminants in effluent discharged from the plant. Intake or discharge structure maintenance,
periodic dredging, and the disposal of dredged sediments may also affect wetlands. Chemical or
fuel spills on nuclear power plant sites can allow contaminants to enter nearby surface or
groundwater, which could affect wetlands that interface with those water sources. Executive
Order 11990, “Protection of Wetlands” (42 FR 26961), requires Federal agencies to not only

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minimize the destruction, loss, or degradation of wetlands while they are conducting their
activities but also to preserve and enhance the natural and beneficial values of wetlands. Many
activities that occur in wetlands are regulated under Section 404 of the CWA. Actions that result
in the discharge of dredge or fill material into wetlands that are covered by the CWA require a
permit from the U.S. Army Corps of Engineers. Additional permits may be required dependent
upon the State and local jurisdictions.
3.6.1.3

Wildlife

Wildlife near nuclear power plants has also been affected by construction and operations.
The initial construction of a nuclear power plant and transmission lines reduced the available
terrestrial habitat at the site; habitat losses in many cases totaled hundreds of acres. Site
maintenance of developed areas generally results in reduced wildlife diversity in these areas
compared to surrounding habitats. Wildlife species occurring on industrial-use portions of
nuclear power plant sites are typically limited by the low quality of the habitat and generally
include common species adapted to industrial developments.
Because habitats along transmission line ROWs are maintained in a modified condition, the
wildlife communities they support are different from those found in undisturbed habitats. Some
predator species, such as skunks and raccoons, more readily use ROW habitats, and ROWs
may therefore provide a means for new or easier access to some areas, thereby affecting
populations of prey species (Evans and Gates 1997; Crooks and Soule 1999). Wildlife species
in the vicinity of transformers or cooling towers are exposed to elevated noise levels that can
disrupt behavior patterns. Wildlife near transmission lines are exposed to electromagnetic fields
(EMFs). However, to date, there is no evidence that ecological resources are affected by EMFs.
Atmospheric or surface water releases can result in the exposure of wildlife to contaminants.
Wildlife is exposed to small amounts of radionuclides from the deposition of particulates
released from nuclear power plant vents during normal operations. Exposure to these
radionuclides results in a dose rate to terrestrial and riparian animals of much less than
0.1 rad/d (0.001 Gy/d), which is the DOE guideline for adequate protection from the effects of
ionizing radiation (DOE 2019) (see Section 4.6.1.1.2).
Nuclear power plant structures, such as cooling towers, meteorological towers, and
transmission lines, create collision hazards for birds. Some bird collisions could be considered
unlawful take if the bird species are protected under the Endangered Species Act (ESA) of
1973, as amended (16 U.S.C. § 1531 et seq.), the Bald and Golden Eagle Protection Act of
1940, as amended (16 U.S.C. §§ 668–668d), or the Migratory Bird Treaty Act of 1918, as
amended (16 U.S.C. § 703 et seq.). Several nuclear power plants with natural draft cooling
towers have conducted studies to investigate the risk of bird collision hazard related to cooling
towers and other site structures. The results of those monitoring efforts indicate that cooling
towers at nuclear power plants do cause some collision mortality for migrating songbirds;
however, these deaths represent only a fraction of the total annual bird collision mortality from
all human-made sources. There are no reports of relatively high collision mortality, such as from
electrocution, occurring from transmission lines associated with nuclear power plants in the
United States. The length of these lines is considerably less than the total of transmission lines
within the United States (Manville 2005). Although the data are not available, transmission lines
associated with nuclear power plants are likely responsible for only a small fraction of total bird
collision mortality associated with transmission lines nationwide (see Section 4.6.1.1.5).
Cooling water systems can have both positive and negative impacts on prey of birds and other
wildlife. Potential fish prey can be impinged or entrained by the cooling water intake system,

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while the fish return system, if present, or heated effluent discharge can provide areas of
concentrated prey availability. Cooling system intakes can also create an impingement hazard
for waterfowl, and water demands for cooling can create water use conflicts with wildlife. At the
Nine Mile Point plant in New York, for example, approximately 100 greater scaup
(Aythya marila) and lesser scaup (Aythya affinis) ducks were impinged at the cooling water
intake structure in 2000 while feeding on zebra mussels (Dreissena polymorpha) during reverse
flow conditions for de-icing of the structure (NRC 2006b). As a result of this incident, the
licensee now cleans the Nine Mile Point intake structures annually to remove zebra mussels,
and reverse flow conditions are scheduled during periods when diving duck feeding is limited
(NRC 2006b). Water use conflicts at the Wolf Creek Generating Station (Wolf Creek) in Kansas
can occur during drought conditions because makeup water for the cooling lake is withdrawn
from the Neosho River, resulting in reduced flows (NRC 2008a). During such times, riparian
communities along the Neosho River can be degraded or lost because of reduced flows, and
wildlife can experience reduced habitat quantity or quality. For some nuclear power plants, State
permits restrict water withdrawal to limit the adverse impacts of water withdrawals (e.g., the
Byron [NRC 2015c] and River Bend plants [NRC 2018c]).
3.6.2

Aquatic Resources

Nuclear power plants are usually located near relatively large waterbodies, such as major rivers
and reservoirs, the Great Lakes, and estuarine and marine coastal areas, which provide a
source of water to meet cooling system demands (Table 3.1-2, Table 3.1-3, Table 3.1-4). In the
few cases where an operating nuclear power plant is located near only small streams (e.g., the
Virgil C. Summer Nuclear Station [Summer] in South Carolina and Clinton plant in Illinois), the
streams have been impounded to create cooling lakes. Aquatic resources associated with these
waterbodies may be affected by nuclear power plant operation. This discussion emphasizes
the major ecosystem types (i.e., freshwater rivers, reservoirs, and lakes and coastal estuarine
and marine systems) and major groups of aquatic biota (i.e., fish, other aquatic vertebrates,
macroinvertebrates, zooplankton, phytoplankton, and macrophytes). Section 3.6.3.1 discusses
federally protected aquatic resources.
3.6.2.1

Aquatic Habitats

The aquatic ecological communities that occur in the vicinity of operating nuclear power plants
are diverse because of the differences in their geographies and habitat types and in the physical
and chemical conditions of the waterbodies located near them. The geographical setting,
physical conditions (e.g., substrate type, temperature, turbidity, and light penetration), chemical
factors (e.g., dissolved oxygen levels and nutrient concentrations), biological interactions
(e.g., competition and predation), seasonal influences, and anthropogenic factors all interact to
influence the types of species present and the nature of the aquatic community in a particular
aquatic ecosystem. Nuclear power plants use freshwater, estuarine, and marine waterbodies as
sources of cooling water, except for the Palo Verde plant, which uses Phoenix City sewage
effluent (Table 3.1-4).
Freshwater systems can be broadly categorized as lentic or lotic, depending on the degree of
water movement. Lentic systems refer to waterbodies that have standing or slow-flowing
water, such as that found in ponds, lakes, reservoirs, and some canals. Lotic habitats generally
have a measurable velocity and include natural rivers and streams and also some artificial
waterways. Although some freshwater aquatic species occur in both lentic and lotic habitats,
many species are adapted to the physical, chemical, and ecological characteristics of

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one system or the other, and the overall ecological communities present within these
aquatic ecosystem types will differ for a given region of the country.
Species composition and ecological conditions within riverine environments are largely
determined by the geographic area, gradient of the riverbed, velocity of the current, and source
of nutrients and organic matter at the base of the food chain. Thus, ecological communities in
rivers become altered if the river is impounded, with the degree of alteration depending on the
degree to which various physical and chemical conditions are affected. These systems are
sensitive to flow depletion or alteration, changes in temperature characteristics, blockages to the
upstream or downstream movement of aquatic organisms, chemical pollution, and the
introduction of non-native species.
Aquatic Ecosystem Types
• Freshwater: Waters with a salinity of 0.5 ppt or less.
–
–

Lentic: Standing or slow-flowing fresh water (e.g., lakes and ponds).
Lotic: Flowing freshwater with a measurable velocity (e.g., rivers and streams).

• Marine: Waters with a salinity of about 35–37 ppt (e.g., ocean overlying the continental shelf
and associated shores).
• Estuarine: Coastal bodies of water, often semi-enclosed, that have a free connection with
marine ecosystems (e.g., bays, inlets, lagoons, and ocean-flooded river valleys). In these
areas, freshwater merges with marine waters; salinity concentrations vary spatially and
temporally due to location and tidal activity.
Major rivers that serve as cooling water sources for operating nuclear power plants include the
Mississippi River, Tennessee River, Missouri River, Susquehanna River, Delaware River, and
Columbia River (see Table 3.1-4). Some nuclear power plants that use rivers for cooling are
located on sections of rivers that have been impounded to slow the rate of flow and create
pooled areas in the vicinity of cooling water withdrawal or discharge structures. These sections
are not as clearly lentic in nature as the reservoirs.
The ecological communities that inhabit the aquatic environment differ, reflecting the
preferences and tolerances of aquatic species at various life stages for the physical and
chemical conditions that exist. A list of cooling water sources by operating nuclear power plant
can be found in Table 3.1-3. Within the United States, nine operating nuclear power plants use
water from natural lakes for cooling. These lakes are Lake Erie, Lake Michigan, and Lake
Ontario.
Reservoirs differ from natural lakes and refer to areas of rivers or streams that are impounded
by a dam or water control structure such that they have become physically, chemically, and
ecologically more similar to lakes instead of the lotic system from which they are formed
(Armantrout 1998). In the United States, 14 nuclear power plants use water from reservoirs for
cooling. Fish species that thrive in the habitat conditions that exist within a given reservoir are
often stocked and managed to support recreational fisheries (see Table 3.1-4).
Brackish to saltwater estuarine and marine ecosystems occur along the coastlines of the
United States. General habitat types found within these ecosystems include the mouths of
rivers, tidal streams, shorelines, salt marshes, beaches, mangroves, submerged aquatic
vegetation, coral reefs, and open water. Estuaries are particularly important as staging points

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during the migration of certain fish species (e.g., salmon and eels) because these waterbodies
give fish time to form schools and to physiologically adjust to changes in salinity. Many marine
fish and invertebrate species use estuaries for spawning or as places where young fish can feed
and grow before moving to other marine habitats. Estuarine and marine habitats support
important commercial or recreational finfish and shellfish species. In the United States,
11 nuclear power plants use water from estuarine or marine environments (see Table 3.1-2).
3.6.2.2

Aquatic Organisms

Major groups of aquatic organisms include fish, other macroinvertebrates, aquatic
macroinvertebrates, zooplankton, phytoplankton and aquatic macrophytes.
Fish can be characterized as freshwater, estuarine, marine, or diadromous (e.g., anadromous
and catadromous) species. The first three categories are based on salinity regimes, whereas
the diadromous category is composed of reproductively specialized fish that migrate between
freshwater and saltwater to reproduce. Murdy et al. (1997) defined freshwater fish as those that
usually inhabit waters with a salinity of less than 0.5 ppt; estuarine fish as those that inhabit tidal
waters with salinities that range between 0 and 30 ppt; and marine fish as those that typically
live and reproduce in coastal and oceanic waters with salinities that are 35 to 37 ppt.
Anadromous species migrate from marine waters to freshwater to spawn, while catadromous
species migrate from freshwater to marine waters to spawn. Anadromous species include
sturgeons, clupeids, salmonids, smelts, striped bass (Morone saxatilus), and sea lamprey
(Petromyzon marinus). Within the United States, the only catadromous species is the American
eel (Anguilla rostrata). For some species, migratory movements may be confined within a
freshwater system (e.g., species tend to move to upstream areas for spawning) or within the
ocean (e.g., species tend to move northward as waters warm and southward as they cool).
Many of the fish species that occur in the vicinity of the nuclear power plants are of commercial
or recreational importance, while others serve as forage for those species.
Fish have various mechanisms to maintain health and fitness during large diurnal or seasonal
changes in water temperature. The swimming performance of fish is influenced by temperature.
A given species’ swimming speed and endurance peak within a certain optimal temperature
range but are reduced at lower or higher temperatures (Claireaux et al. 2006). Many marine fish
have buoyant eggs while most stream fish have demersal eggs that are heavy and sink to the
bottom of the water column. Most demersal eggs are also, at least temporarily, adhesive (Lagler
et al. 1962). Newly hatched larvae undergo natural mortality rates of 5 to 30 percent per day as
a result of predation, starvation, disease, pollution, and other causes (Batty and Blaxter 1992).
In addition to fish, other vertebrate species can be present in the aquatic ecosystems near
nuclear power plants. These include marine reptiles, such as sea turtles, and marine mammals,
such as whales, seals, and the West Indian manatee (Trichechus manatus).
Aquatic macroinvertebrates include a diverse range of taxa, including immature and adult
insects, crustaceans, mollusks, and worms. These can occur on a variety of stable surfaces
such as substrates, plants, debris, etc., and within the water. Macroinvertebrates control key
ecosystem processes, such as primary production, decomposition, nutrient regeneration, water
chemistry, and water clarity.
Nuisance or invasive species can be present in cooling water sources. For example, Asiatic
clams (Corbicula fluminea) and zebra mussels can alter the trophic and nutrient dynamics of
aquatic ecosystems and displace native mussels. Executive Order 13112, “Invasive Species”

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(64 FR 6183), directs Federal agencies to prevent introduction of or to monitor and control
invasive species. Many nuclear power plants monitor for these species and periodically use
physical or chemical methods to control biofouling of cooling system structures and
components.
Zooplankton include protozoans, crustaceans, and the drifting larvae of fish and
macroinvertebrates. Rotifers, cladocerans, and copepods are primary components of the
zooplankton community in freshwater ecosystems. The zooplankton of estuarine and marine
ecosystems include eggs, larvae, juveniles, and adults of anemones, jellyfish, bristleworms, sea
urchins, starfish, copepods, isopods, amphipods, shrimp, crabs, lobsters, bryozoans, and
mollusks. Ichthyoplankton, which are fish eggs and larvae, are a seasonal component of the
zooplankton in all aquatic ecosystems. Zooplankton are an important link between
phytoplankton and fish or other secondary consumers.
Phytoplankton are an important food source for some invertebrate and fish species and are
important for converting carbon dioxide (CO2) to organic materials via photosynthesis.
Periphyton are algae attached to solid submerged objects and include species of diatoms and
other algae that grow on natural or artificial substrates. These species can become planktonic
as a result of scouring or other actions that separate individuals from their substrate.
Components of phytoplankton include green algae (Chlorophyta), blue-green algae
(Cyanophyta), and golden brown algae (Chrysophyta). Brown algae and kelp (Phaeophyta) and
red algae (Rhodophyta) also occur in marine waters. Diatoms (Bacillariophyta) are a major
component of the phytoplankton in many aquatic systems. Macrophytes can stabilize
sediments, act as important links in nutrient cycling, provide shelter and protection for animal
communities, and provide important nursery areas (Hall et al. 1978). Factors that affect the
distribution and condition of submersed aquatic vascular plants include weather and hydrology,
sedimentation, suspended solids and water clarity, and consumption and disturbance by fish
and wildlife (USGS 1999).
3.6.2.3

Effects of Existing Nuclear Plant Operations on Aquatic Resources

The effects of nuclear power plant operations on aquatic resources include impingement and
entrainment of aquatic organisms into the cooling water intake system, effects associated with
thermal discharges, and chemical and radiological contamination.
Impingement occurs when organisms are trapped against the outer part of an intake structure’s
screening device (79 FR 48300). The force of the intake water traps the organisms against the
screen, and individuals are unable to escape. Impingement can kill organisms immediately or
cause exhaustion, suffocation, injury, and other physical stresses that contribute to later
mortality. The potential for injury or death is generally related to the amount of time an organism
is impinged, its fragility (susceptibility to injury), and the physical characteristics of the screen
wash and fish return systems of the intake structure. Entrainment occurs when organisms pass
through the screening device and travel through the entire cooling system, including the pumps,
condenser or heat exchanger tubes, and discharge pipes (79 FR 48300). Organisms
susceptible to entrainment are of smaller size, such as ichthyoplankton, meriplankton,
zooplankton, and phytoplankton. Impingement and entrainment occurs at all nuclear power
plants that withdraw water from a natural waterbody. The magnitude of impact that impingement
and entrainment creates on the aquatic environment depends on the plant-specific
characteristics of the cooling system as well as the characteristics of the local aquatic
community.

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Temperature can influence most biochemical, physiological, and life history activities of aquatic
organisms (Beitinger et al. 2000). Thermal effects on aquatic biota can be lethal, sub-lethal, or
community-level. These effects include heat shock; cold shock; interference with fish migration;
accelerated maturation of aquatic insects; and proliferated growth of aquatic nuisance species.
Nuclear power plants also affect aquatic organisms through radiological and nonradiological
chemical releases. Chemical effects on aquatic biota can occur from exposure to biocides and
other contaminants (e.g., heavy metals such as copper, zinc, and chromium that may be
leached from condenser tubing and other heat exchangers). Blowdown from closed-cycle
cooling systems can contain concentrated levels of constituents present in the makeup water,
residual biocides, process contaminants, and other chemicals added for controlling corrosion or
deposits (DOE 1997a). Radionuclides are released to aquatic systems at or below permitted
levels at nuclear power plants (10 CFR Part 20, Appendix B). Radionuclides can be
environmentally significant because they have a strong tendency to adsorb onto particles
(e.g., suspended and settled solids), can accumulate in biological organisms, or can be
concentrated through trophic transfers (MDNR 2019). However, exposure to radionuclides
results in a dose rate to aquatic organisms of much less than 1.0 rad/d (0.1 Gy/d), which is the
DOE guideline for adequate protection from the effects of ionizing radiation (DOE 2019) (see
Section 4.6.1.2.8). Radionuclides, such as tritium, and other constituents in cooling water
systems, such as biocides, can enter aquatic systems and be taken up by aquatic plants and
animals.
The impact of any type of nuclear power plant on aquatic resources can be difficult to determine
because individual organisms and populations also respond to changes in environmental
conditions (EPA 2002). Table 3.6-1 lists factors that influence the impacts of nuclear power
plant operation on aquatic organisms, including characteristics of the nuclear power plant itself,
as well as physical and biological ecosystem factors.
Table 3.6-1

Factors That Influence the Impacts of Nuclear Power Plant Operation on
Aquatic Organisms

Nuclear Power Plant Factors
• Volume of water withdrawn from source waterbody, which generally relates to type of cooling
system (e.g., once-through, cooling tower, cooling pond, or hybrid)
• Cooling water intake velocity
• Intake and discharge location (e.g., distance from shoreline, depth of intake, biological richness of
area, proximity to spawning and rearing habitat)
• Exclusion technologies (e.g., traveling screens and mesh size, screen wash characteristics, fish
return system, capture and release programs)
• Thermal effluent temperature when entering receiving waterbody
• Thermal plume characteristics (e.g., surface area, depth, isotherm contours)
• Mitigation strategies (e.g., helper cooling tower operation, seasonal water withdrawal reductions,
timing of outages, multiport or jet diffusers that promote rapid mixing of effluent)
• Radiological effluents
• Nonradiological chemical contaminants (e.g., chlorine, heavy metals, biocides)
• Dredging to improve intake flow and keep intake and discharge areas clear of sediment
• Water use conflicts with aquatic resources

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Physical Ecosystem Factors
• Waterbody type (e.g., riverine, lacustrine, estuarine, marine)
• Ambient water temperatures and seasonal regimes
• Ambient water quality (e.g., salinity, dissolved oxygen, pollutant levels)
• Stream flow and tidal influence
• Other human-induced stressors (e.g., dams, agricultural runoff, other industrial water users)
Biological Ecosystem Factors
• Spatial and temporal distribution of aquatic organisms and populations
• Species richness and evenness
• Population abundances and trends
• Habitat and sediment types present
• Seasonality of habitat use and migratory patterns of species
• Developmental stage of organism (e.g., egg, larvae, juvenile, adult)
• Body size of organism
• Condition and health of organism
• Ability of organism to detect or avoid flow of water into cooling water intake system
• Swimming capability of organism (e.g., burst, prolonged, and sustained swimming speeds)
• Physiological tolerance to abiotic factors (e.g., temperature, salinity, dissolved oxygen)
• Reproductive strategy and characteristics (e.g., location of spawning, mode of egg and larval
dispersal)
• Predation pressures

3.6.3

Federally Protected Ecological Resources

The NRC must consider the effects of its actions on ecological resources protected under
several Federal statutes and must consult with the FWS or the National Oceanic and
Atmospheric Administration (NOAA) prior to taking action in cases where an agency action may
affect those resources. These statutes include the following:
• Endangered Species Act of 1973, as amended (ESA) (16 U.S.C. § 1531 et seq.)
• Magnuson-Stevens Fishery Conservation and Management Act (MSA), as amended by the
Sustainable Fisheries Act of 1996 (16 U.S.C. § 1801 et seq.)
• National Marine Sanctuaries Act (NMSA) (16 U.S.C. § 1431 et seq.)
The FWS and the NOAA’s National Marine Fisheries Service (NMFS) (collectively, “the
Services”) promulgated regulations on interagency consultation under the ESA in 1986
(51 FR 19926). Depending on when a nuclear power plant was constructed and began
operating, the NRC staff may have consulted with one or both Services under the ESA during
initial permitting and licensing. NMFS promulgated regulations on interagency consultation
under the MSA in 2002 (67 FR 2343). Congress amended the NMSA to require interagency
coordination with NOAA’s Office of National Marine Sanctuaries (ONMS) in 1992 (National
Marine Sanctuaries Program Amendments Act of 1992). The NRC staff did not conduct
essential fish habitat (EFH) and NMSA consultations during initial permitting and licensing of
any current nuclear power plants within the scope of this revised LR GEIS, including those that
have been decommissioned or are in decommissioning, because these statutes had either not
been passed or had not been amended to require consultation; however, rare species and
unique ecological habitats were often considered in project planning. The NRC staff did not

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conduct EFH consultation for the first several initial LR reviews because these reviews were
also conducted prior to the establishment of consultation requirements.
The sections below discuss species and habitats protected under each of the three statutes and
how nuclear power plant operation during an initial LR or SLR term may affect these protected
resources.
3.6.3.1

Endangered Species Act

Congress enacted the ESA in 1973 to protect and recover imperiled species and the
ecosystems upon which they depend. The ESA provides a program for the conservation of
endangered and threatened plants and animals (collectively, “listed species”) and the habitats in
which they are found. The FWS and NMFS are the lead Federal agencies for implementing the
ESA, and these agencies are charged with determining species that warrant listing.
Section 7 of the ESA establishes interagency consultation requirements for actions by Federal
agencies. Section 7(a)(1) of the ESA charges Federal agencies to aid in the conservation of
listed species. Section 7(a)(2) of the ESA requires that Federal agencies consult with the
Services for actions that “may affect” federally listed species and critical habitats and to ensure
that their actions do not jeopardize the continued existence of those species or destroy or
adversely modify those habitats. Private actions with a Federal nexus, such as construction and
operation of facilities that involve Federal licensing or approval, are also subject to consultation.
Therefore, the NRC’s issuance of initial or subsequent renewed licenses may trigger
consultation requirements. Consultation pursuant to ESA Section 7(a)(2) is commonly referred
to as “Section 7 consultation.”
Section 9 of the ESA prohibits any action that causes a “take” of any listed species of
endangered fish or wildlife by any person or entity. Take, as defined under the ESA, means to
harass, harm, pursue, hunt, shoot, wound, kill, trap, capture, or collect, or to attempt to engage
in any such conduct. Likewise, import, export, interstate, and foreign commerce of listed species
are all generally prohibited.
Species listings and critical habitat designations require rulemakings and are codified at
50 CFR Part 17, “Endangered and Threatened Wildlife and Plants.” As of 2023, over
700 animals and 900 plants are listed as endangered or threatened, and the Services have
designated critical habitat for many of these species. Given this large number, listed species are
likely to occur near all operating nuclear power plants. However, the potential for a given
species to occur in the action area of a specific nuclear power plant depends on the life history,
habitat requirements, and distribution of that species and the ecological environment present on
or near the power plant site. The “action area” is a regulatory term. It includes all areas to be
affected directly or indirectly by the Federal action and not merely the immediate area involved
in the action (50 CFR 402.02). The action area is not limited to the footprint of the action nor is it
limited by the Federal action agency’s authority; rather, it is a biological determination of the
reach of the proposed action on the listed species.
In general, estuarine or marine listed species may occur in the action area of plants that draw
directly from estuaries or the ocean. Examples of such species include listed species of
sturgeon, sea turtles, whales, and salmon. Freshwater listed species, such as mussels and
pallid sturgeon (Scaphirhynchus albus), may occur in the action area of plants that draw directly
from freshwater sources, such as rivers or Great Lakes. Listed aquatic species are generally
less likely to be present in constructed habitats, such as cooling ponds or canals, that do not

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hydrologically connect to natural surface waters from which colonization or immigration could
occur. The presence of terrestrial listed species is highly dependent upon habitat availability and
quality on or near the nuclear power plant site. Northern long-eared bats (Myotis septentrionalis)
and Indiana bats (M. sodalis) are widely distributed across the eastern and north central United
States and may be present at any site within their ranges whose habitat provides sufficient
forage, roosting, or hibernating opportunities. Likewise, listed migratory birds may seasonally
inhabit the action area of a nuclear power plant whose site provides even marginal stopover
habitat, especially if that site is within one of the four major North American flyways.
Table 3.6-2 and Table 3.6-5 identify critical habitats and listed species that the NRC staff, in
consultation with the Services, evaluated during initial LR or SLR environmental reviews
conducted since development of the 2013 LR GEIS. As part of the 19 environmental reviews
identified below (see Table 3.6-5), the NRC staff evaluated 107 listed species and designated
critical habitat of 7 listed species. Many of the same species were present in the action area of
multiple nuclear power plants. The most commonly evaluated terrestrial species were northern
long-eared bats (11 license renewal reviews), Indiana bat (9 reviews), piping plover
(Charadrius melodus) (6 reviews), eastern prairie fringed orchid (Platanthera leucophaea)
(5 reviews), and rufa red knot (Calidris canutus rufa) (4 reviews). The most commonly evaluated
aquatic species were Atlantic sturgeon (Acipenser oxyrinchus) (5 reviews), shortnose sturgeon
(A. brevirostrum) (5 reviews), and pallid sturgeon (Scaphirhynchus albus) (4 reviews). Notably,
the NRC staff evaluated the effects of nuclear power plant license renewal on all five of the
listed Atlantic sturgeon distinct population segments (DPSs) among the five evaluations of this
species. All other species listed in Table 3.6-5 were evaluated in three license renewal reviews
or less.
Table 3.6-2
Nuclear
Power Plant
Grand Gulf
Grand Gulf
LaSalle
Indian Point(a)

Critical Habitats Evaluated in License Renewal Reviews, 2013–Present
FWS Critical Habitat
Louisiana black bear
rabbitsfoot mussel(d)
Indiana bat
-

Turkey Point(b) American crocodile
Turkey Point(b) West Indian manatee
Surry(b)
Atlantic sturgeon,
Chesapeake Bay DPS
(b)
Point Beach
piping plover

Final Effect
Determination(c))

NMFS Critical
Habitat

Final Effect
Determination(c)

NE
NE
NE
-

Atlantic sturgeon, New
York Bight DPS(a)
Atlantic sturgeon,
Chesapeake Bay DPS
-

NLDM

LDM
NLDM
NLDM
NE

NLDM
-

DPS = distinct population segment; FWS = U.S. Fish and Wildlife Service; LDM = likely to destroy or adversely
modify; NMFS = U.S. National Marine Fisheries Service; NE = no effect; NLDM = may affect but is not likely to
destroy or adversely modify.
(a) The evaluation of this species was a part of a review that supplemented the NRC’s Final Supplemental
Environmental Impact Statement (final SEIS).
(b) This review evaluated an SLR term.
(c) The effect determinations provided here are the final determinations concerning each species that resulted from
consultation with the Services. In some cases, the Service’s letter of concurrence revised or amended the NRC
staff’s original effect determinations for a given species.
(d) At the time the NRC staff performed its review, critical habitat for this species was proposed for Federal listing.
The Services have now issued a final rule designating this critical habitat.
No entry has been denoted by “-”.
Sources: NRC 2014e, NRC 2016d, NRC 2018e, NRC 2019c, NRC 2020f, NRC 2021f.

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Critical habitat represents the habitat that contains the physical or biological features essential
to conservation of the listed species and that may require special management considerations
or protection (78 FR 53058). Critical habitat may also include areas outside the geographical
area occupied by the species if the Services determine that the area itself is essential for
conservation. The NRC staff evaluated the critical habitat of seven listed species among six
license renewal reviews since publication of the 2013 LR GEIS. Notably, the FWS has
designated much of the Turkey Point site in Florida, including the plant’s artificial CCS, as
critical habitat for the American crocodile (Crocodylus acutus). At the Surry Power Station
(Surry) plant in Virginia, the entirety of the James River in the action area of the plant is
designated as critical habitat for the Chesapeake Bay DPS of Atlantic sturgeon. The Hudson
River within the action area of the Indian Point plant (no longer operating) in New York is
designated critical habitat for the New York Bight DPS of Atlantic sturgeon. At the Point Beach
Nuclear Plant (Point Beach) in Wisconsin, the FWS has designated critical habitat for the
Great Lakes population of piping plover approximately 3 mi (5 km) south of the plant site along
the shoreline of Lake Michigan.
As the Services continue to evaluate species for listing and delisting, new species may be
relevant to license renewal reviews and additional critical habitat designations may occur near
operating nuclear power plants. This means that for a given plant, the staff may be required to
evaluate different or additional listed species and critical habitats during an SLR review than the
staff evaluated during the initial LR review for that same plant.
Listed species and critical habitats can be adversely affected by the same factors described in
Sections 3.6.1 and 3.6.2 relevant to terrestrial and aquatic resources. However, the magnitude
and significance of such impacts can be greater for listed species because—by virtue of being
eligible for Federal listing—these species are significantly more sensitive to environmental
stressors as their populations are already in decline. Similarly, critical habitats are afforded
special protections because they are critical to the preservation of the listed species.
In cases where adverse effects on listed species or critical habitats are possible, the NRC staff
has engaged the Services in formal ESA Section 7 consultation as part of the license renewal
review and obtained a biological opinion. A biological opinion evaluates the nature and extent of
effects of the action on listed species and critical habitats. It is prepared by the FWS or NMFS
and documents the Service’s assessment of effects on listed species and critical habitat and
whether the Federal action is likely to jeopardize the continued existence of those species or
result in destruction or adverse modification of critical habitat. Biological opinions may include
an incidental take statement (ITS) consisting of the level of anticipated take, reasonable and
prudent measures, and terms and conditions. Any take that is subject to and in compliance with
an ITS is not prohibited under the ESA. Biological opinions may also include discretionary
conservation recommendations.
For consultations resulting in the Service’s issuance of a biological opinion, the NRC requires its
licensees to comply with the ITS of the biological opinion by incorporating environmental
conditions into the relevant NRC facility license(s). As conditions of NRC-issued licenses, the
NRC has a continuing duty to monitor compliance at facilities with valid biological opinions. This
role is performed by the NRC’s Interagency Consultation Coordinator. The NRC may exclude
specific ITS requirements from its license(s) if another Federal agency will require those actions
be taken.
Since development of the 2013 LR GEIS, the Services have issued eight biological opinions in
connection with continued operation of nuclear power plants during an initial LR or SLR term.

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Affected Environment
These biological opinions are for the Indian Point (no longer operating), Salem and Hope Creek,
St. Lucie Nuclear Plant (St. Lucie), Columbia Generating Station (Columbia), Turkey Point, and
Oyster Creek (no longer operating) plants. In the case of Salem, Hope Creek, and St. Lucie, the
Services have issued multiple biological opinions for these plants since 2013. Biological
opinions include an ITS that allows for a specified amount of take of these species that is
incidental to, and not the purpose of, carrying out the Federal action of license renewal, as well
as reasonable and prudent measures and terms and conditions to minimize such take. In
accordance with these requirements, these plants monitor and report the effects of continued
operation under the license renewal terms to the Services and the NRC. In total, NMFS has
issued biological opinions to address take of listed fish and sea turtles resulting from
impingement, entrainment, or entrapment at 10 nuclear power plants. Table 3.6-3 lists the
nuclear plants and relevant species to which these opinions apply. The FWS has issued one
biological opinion to address the effects of operation of the Turkey Point plant. Table 3.6-4 lists
the species to which this opinion applies.
Table 3.6-3

National Marine Fisheries Service-Issued Biological Opinions for Nuclear
Power Plant Operation

Nuclear Power
Plant
Brunswick

Columbia

Crystal River(a)

Diablo Canyon

Hope Creek(b)

Indian Point(c)

Oyster Creek(d)

Salem

Issue Date

Species Addressed in ITS

January 1, 2000

green sea turtle
hawksbill sea turtle
Kemp’s ridley sea turtle
leatherback sea turtle
loggerhead sea turtle
March 10, 2017
chinook salmon, Upper Columbia
River spring run
steelhead, Upper Columbia River
August 8, 2002
green sea turtle
hawksbill sea turtle
Kemp’s ridley sea turtle
leatherback sea turtle
loggerhead sea turtle
September 18, 2006
green sea turtle
leatherback sea turtle
loggerhead sea turtle
olive ridley sea turtle
July 17, 2014, as clarified on none(c)
November 23, 2018, and
later replaced by a new
opinion on March 24, 2023
January 30, 2013, as
Atlantic sturgeon
amended on April 10, 2018, shortnose sturgeon
and October 5, 2020
May 29, 2020
green sea turtle
Kemp’s ridley sea turtle
loggerhead sea turtle
July 17, 2014, as clarified on Atlantic sturgeon
November 23, 2018, and
shortnose sturgeon
later replaced by a new
green sea turtle
opinion on March 24, 2023
Kemp’s ridley sea turtle
loggerhead sea turtle

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Opinion Reference
NRC 2000

NMFS 2017

NMFS 2002

NMFS 2006

NMFS 2014c
NMFS 2018c
NMFS 2023
NMFS 2013
NMFS 2018a
NMFS 2020a
NRC 2020b

NMFS 2014c
NMFS 2018c
NMFS 2023

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Nuclear Power
Plant
Issue Date
(e)
San Onofre
September 18, 2006

St. Lucie

March 24, 2016, and later
replaced by a new opinion
on August 15, 2022

Species Addressed in ITS
green sea turtle
leatherback sea turtle
loggerhead sea turtle
olive ridley sea turtle
green sea turtle
hawksbill sea turtle
Kemp’s ridley sea turtle
leatherback sea turtle
loggerhead sea turtle
smalltooth sawfish

Opinion Reference
NMFS 2006

NMFS 2016
NMFS 2022b

ITS = incidental take statement.
(a) Crystal River plant shut down in February 2013. In a letter dated January 24, 2022, NMFS (2022a) confirmed
that the 2002 biological opinion is no longer applicable because the plant’s cooling water intake system has been
repurposed and modified for the Duke Energy Citrus Combined Cycle Station and is currently compliant with the
2014 programmatic biological opinion on the U.S. Environmental Protection Agency’s final regulations
implementing Section 316(b) of the Clean Water Act (FWS/NMFS 2014).
(b) In its biological opinion, National Marine Fisheries Service (NMFS) evaluates the potential effects of Hope Creek
operations on Atlantic and shortnose sturgeon and sea turtles but does not exempt incidental take at this plant
because none is anticipated.
(c) Indian Point 2 ceased power operations in April 2020, and Indian Point 3 ceased in April 2021. Certain terms and
conditions of the biological opinion continue to impose requirements during the decommissioning period.
(d) Oyster Creek plant ceased power operations in September 2018. The 2020 biological opinion addresses the
effects of the last several years of operation as well as decommissioning. Although NMFS’s prior biological
opinion, issued on November 21, 2011, allowed for incidental take of sea turtles in the form of impingement into
the cooling system intake system, the 2020 biological opinion does not exempt any additional take and does not
include an ITS.
(e) San Onofre plant ceased power operations in June 2013. As of mid-2022, the NRC is in reinitiated consultation
with NMFS to address the potential impacts of decommissioning on federally listed species. At the conclusion of
consultation, NMFS may issue a new biological opinion if it determines that take is anticipated during the
decommissioning period, or NMFS may not issue a new biological opinion and conclude consultation informally if
take is not anticipated.

Table 3.6-4 U.S. Fish and Wildlife Service-Issued Biological Opinions for Nuclear Power
Plant Operation
Nuclear Power
Plant
Turkey Point

Issue Date
July 25, 2019, as amended
on March 21, 2022

Species Addressed in ITS
American crocodile
eastern indigo snake

Opinion Reference
FWS 2019a
FWS 2022a

ITS = incidental take statement.

The primary concern for listed aquatic species at operating nuclear power plants is the effects
associated with operation of the cooling system. Listed fish, shellfish, and sea turtles are
vulnerable to impingement, entrainment, and entrapment at plants that withdraw cooling water
from natural waterbodies, such as rivers, estuaries, and the ocean. Open-cycle cooling systems
withdraw more water, and at a typically higher velocity, than cooling-tower-based closed-cycle
systems. Therefore, risk of impingement, entrainment, and entrapment is greater at these
facilities.
Sea turtles are susceptible to impingement or entrapment at numerous once-through oceanic
plants. For instance, at the St. Lucie plant in Florida, marine organisms can enter one of three

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intake pipes located in the Atlantic Ocean and be drawn into the intake canal where they
become entrapped. Since operations began in the late 1970s, St. Lucie plant has collected
seven listed species in its intake canal: five species of sea turtles,7 smalltooth sawfish
(Pristis pectinata), and giant manta rays (Mobula birostris). Additionally, the plant collected two
scalloped hammerhead sharks (Sphyrna lewini) prior to the NMFS’s listing of this species in
2014. The NRC (2019a) most recently evaluated the impacts of St. Lucie plant operations on
federally listed species in a 2019 biological assessment prepared to support reinitiated ESA
Section 7 consultation. In that assessment, the NRC found that sea turtles could become injured
or die from travel through the intake pipes or from entanglement in barrier nets within the intake
canal. Turtles could suffer additional stress associated with capture and release. The NRC
found that smalltooth sawfish may experience minor to moderate injury because of St. Lucie’s
cooling water intake system. In 2022, NMFS concluded that continued operation of St. Lucie is
likely to adversely affect, but will not jeopardize the continued existence of these species and
issued a new biological opinion (NMFS 2022b). Sea turtle impingement or entrapment has also
occurred at six other nuclear power plants: (1) Oyster Creek in New Jersey (no longer
operating); (2) Salem in New Jersey; (3) Brunswick Steam Electric Plant (Brunswick) in North
Carolina; (4) Crystal River Nuclear Power Plant (Crystal River) in Florida (no longer operating);
(5) Diablo Canyon in California; and (6) San Onofre (no longer operating) in California. NMFS
has issued biological opinions for each of these plants to address these effects (see
Table 3.6-3).
At coastal northeast plants, Atlantic and shortnose sturgeon can become impinged or entrained
on trash racks, traveling screens, or other components of the cooling water intake system.
NMFS has issued biological opinions for both the Salem and Indian Point (no longer operating)
plants to address these effects (Table 3.6-3). At other plants, although sturgeon are in the action
area, the NRC and NMFS have determined that impingement and entrainment are not likely.
For instance, at the Surry plant, the NRC (2020f) found that impingement of shortnose and
Atlantic sturgeon is extremely unlikely to occur during the SLR term because the life stages of
sturgeon in the action area would be of sufficient size and swimming capability to resist the flow
of water into Surry’s low-level intake structure. The NRC (2020f) found that entrainment does
not pose a risk to sturgeon because entrainable life stages do not occur in the action area.
NMFS (2020b) concurred with this determination and did not issue a biological opinion for
this plant.
At the Columbia plant in Washington, Upper Columbia River spring run Chinook salmon
(Oncorhynchus tshawytscha) and Upper Columbia River steelhead (O. mykiss) are susceptible
to impingement on the intake screens or entrainment into the intake system because these
species migrate past the plant seasonally as fry, which are only a few centimeters in length at
this life stage. Notably, following the license renewal review, the licensee conducted fish
entrainment characterization studies that showed that very few fish of any species are entrained
into Columbia’s cooling water intake system due to its design, which hydraulically deflects fish
from becoming trapped on or passing through the intake screens. Neither of the two listed
salmon species were collected during the study. Nonetheless, because Chinook salmon fry are
small and seasonally abundant in the Hanford Reach of the Columbia River, researchers
estimated that one to two Chinook salmon fry could have been entrained during the two-year
study period (Anchor QEA, LLC 2020). Such take, if it occurred, is allowable under the NMFS’s
2017 biological opinion (see Table 3.6-3).

7

The species of sea turtles are green (Chelonia mydas), hawksbill (Eretmochelys imbricata), leatherback
(Dermochelys coriacea), loggerhead (Caretta caretta), and Kemp’s ridley (Lepidochelys kempii).

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Effects associated with thermal effluent discharge are another primary concern for aquatic listed
species and their critical habitats. Cooling water discharges are regulated by the EPA, or
authorized States or Tribes, under Section 316(a) of the CWA. Thermal effluent criteria and
limitations are imposed on many plants through special conditions in the site NPDES permit.
Under CWA Section 316(a), EPA or the States must establish thermal effluent limitations that
assure the protection and propagation of the waterbody’s balanced, indigenous population of
shellfish, fish, and wildlife. Nonetheless, thermal discharges can affect habitat availability and
fish behavior or migration. For instance, if a thermal plume extends across a river, it can affect
fish migration by causing individuals to exert additional energy to avoid heated water, or it can
block passage altogether. In general, the NRC has found thermal effects on listed species to be
insignificant or discountable, and the NMFS has concurred on these findings during
consultation.
Listed terrestrial species, including bats, birds, mammals, reptiles, amphibians, and
invertebrates, can be affected by habitat loss, degradation, disturbance, or fragmentation
resulting from construction, refurbishment, or other site activities, including site maintenance
and infrastructure repairs, during the license renewal term. In general, the NRC staff has not
found habitat alteration to be of concern in past NRC license renewal reviews. Nuclear power
plant sites are already fully developed to support power operations, and neither initial LR nor
SLRs generally require additional development that would affect natural habitats on or
surrounding the site.
Noise and vibration and general human disturbance are stressors that can disrupt normal
feeding, sheltering, and breeding activities. At low noise levels or farther distances, animals
initially may be startled but would likely habituate to the low background noise levels. At louder
noise levels and closer range, animals would likely be startled to the point of fleeing from the
area. Fleeing individuals would expend increased levels of energy and would forgo the foraging,
resting, or breeding opportunities that the action area may have otherwise provided. However,
listed species that use the action area of operating nuclear power plants have likely become
habituated to such disturbance because these plants have been consistently operating for
several decades. For instance, the NRC (2021f) found that continued disturbances during the
SLR term of the Point Beach plant in Wisconsin would not cause behavioral changes in piping
plovers to a degree that would be able to be meaningfully measured, detected, or evaluated or
that would reach the scale where a take might occur. The FWS (2021) concurred with this
determination.
Listed bats can be vulnerable to mortality or injury from collisions with plant structures and
vehicles. Bat collisions with human-made structures at nuclear power plants are not well
documented but are likely rare based on the available information. In an assessment of the
potential effects of operation of the Davis-Besse Nuclear Power Station (Davis-Besse) plant in
Ohio, the NRC (2014a) noted that four dead bats were collected at the plant during bird
mortality studies conducted from 1972 through 1979. Two red bats (Lasiurus borealis) were
collected at the cooling tower, and one big brown bat (Eptesicus fuscus) and one tri-colored bat
(Perimyotis subflavus) were collected near other plant structures. During the initial LR review,
the NRC (2014a) found that future collisions of bats would be extremely unlikely and, therefore,
discountable given the small number of bats collected during the study and the marginal
suitable habitat that the plant site provides. The FWS (2014) concurred with this determination.
In a 2015 assessment associated with the Indian Point plant in New York, the NRC (2015a)
determined that bat collisions were less likely to occur at the Indian Point plant than at the
Davis-Besse plant because Indian Point does not have cooling towers or similarly large
obstructions. The tallest structures on the Indian Point site are 134 ft (40.8 m) tall turbine

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Affected Environment
buildings and 250 ft (76.2 m) tall reactor containment structures. The NRC (2015a) concluded
that the likelihood of bats colliding with these and other plant structures on the Indian Point site
during the license renewal period was extremely unlikely and, therefore, discountable. The
FWS (2015b) concurred with this determination. In 2018, the NRC (2018a) determined that the
likelihood of bats colliding with site buildings or structures on the Seabrook Station (Seabrook)
site in New Hampshire would be extremely unlikely. The tallest structures on that site are a
199 ft (61 m) tall containment structure and 103 ft (31 m) tall turbine and heater bay building.
The FWS (2018) concurred with the NRC’s determination. In 2020, the NRC (2020f) determined
that the likelihood of bats colliding with site buildings or structures on the Surry site in Virginia
would be extremely unlikely. The FWS (2019b) again concurred with the NRC staff’s
determination on the basis that activities associated with the Surry plant SLR would be
consistent with the activities analyzed in the FWS’s January 5, 2016, programmatic biological
opinion (FWS 2016). Most recently, the NRC (2021f) determined that the likelihood of bats
colliding with site buildings or structures at the Point Beach plant in Wisconsin would be
extremely unlikely based on structure height and operating experience. The FWS (2021) also
concurred with this determination based on the FWS’s 2016 programmatic biological opinion
(FWS 2016).
Unlike bat collision risk, the risk of bird collisions is more species-specific and depends on the
particular life history, behaviors, and flight patterns of a species. For example, in 2014, the
FWS (2014) used mortality data for blackpoll warbler (Setophaga striata), an unlisted species, to
estimate future mortality of the Kirtland’s warbler (S. kirtlandii)8 at the Davis-Besse site during
the license renewal term because the two species are similar. Because blackpoll warblers had
been collected during past bird and bat mortality studies, the FWS determined that Kirtland’s
warbler mortality from collisions with the site’s cooling tower or meteorological tower was
possible. However, the FWS estimated the total Kirtland’s warbler mortality during the seasonal
migratory periods over the license renewal period to be less than 0.01 birds. Therefore, the
FWS determined that no take was ultimately expected, and the FWS concurred with the
NRC’s (2014a) determination that the likelihood of this bird colliding with nuclear power plant
buildings and structures is discountable or extremely unlikely to occur. In the same review, the
FWS (2014) determined that red knot collisions were also a discountable effect due to the
specific habitat needs of this species and the limited number that have been observed in Ohio,
and the FWS did not calculate mortality for this species.
In 2016, the NRC (NRC 2016c) found that the risk of both red knots and piping plovers colliding
with plant buildings or structures at the Enrico Fermi Atomic Power Plant (Fermi) site in
Michigan would be extremely unlikely to occur. The NRC made these determinations based on
species-specific factors. For red knots, the NRC made this determination because this species
is rare in the action area; the last red knot observed at the Fermi site was in 1973. For piping
plovers, the NRC made this determination because individuals are not likely to inhabit inland
developed portions of the site that contain collision hazards. Factors relevant to both species
included seasonal migration periods and the absence of the two species in bird mortality
surveys conducted on the site. The FWS (2015a) concurred with the NRC’s determination that
Fermi license renewal was not likely to adversely affect these species.

At the time of this review, the Kirtland’s warbler was listed as endangered. The FWS has since delisted
this species due to recovery (84 FR 54436).
8

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Nuclear Power
Plant
FWS Species(c)
Seabrook
piping plover (Charadrius melodus)

Seabrook
Seabrook

roseate tern (Sterna dougallii)
-

Final Effect
Determination(d)
NLAA

NLAA
-

3-64

Seabrook

-

-

Seabrook

-

-

Seabrook

-

-

Seabrook

-

-

Seabrook

-

-

South Texas

American alligator (Alligator mississipiensis)

N/A

South Texas

Eskimo curlew (Numenius borealis)

NE

South Texas

Louisiana black bear
(Ursus americanus luteolus)
northern aplomado falcon
(Falco femoralis septentrionalis)
ocelot (Leopardus pardalis)
piping plover

NE

South Texas
South Texas
South Texas
South Texas
South Texas
South Texas
South Texas

red wolf (Canis rufus)
smooth pimpleback
(Quadrula houstonensis)(f)
Texas fawnsfoot (Truncilla macrodon)(f)
West Indian manatee
(Trichechus manatus)

NLAA
NE
NE
NE
NE
NE
NE

Final Effect
NMFS Species(c)
Determination(d)
Atlantic sturgeon
NLAA
(Acipenser oxyrinchus oxyrinchus),
Gulf of Maine DPS(g)
fin whale (Balaenoptera physalus)
NLAA
humpback whale
NLAA
(Megaptera novaeangliae)
Kemp’s ridley sea turtle
NLAA
(Lepidochelys kempii)
leatherback sea turtle
NLAA
(Dermochelys coriacea)
loggerhead sea turtle
NLAA
(Caretta caretta)
North Atlantic right whale
NLAA
(Eubalaena glacialis)
Shortnose sturgeon
NLAA
(Acipenser brevirostrum)
green sea turtle
NE
(Chelonia mydas)(e)
hawksbill sea turtle
NE
(Eretmochelys imbricata)
Kemp's ridley sea turtle
NE
leatherback sea turtle

NE

loggerhead sea turtle(e)
smalltooth sawfish
(Pristis pectinata), U.S. DPS
-

NE
NE

-

-

Affected Environment

NUREG-1437, Revision 2

Table 3.6-5 Endangered Species Act Listed Species Evaluated in License Renewal Reviews, 2013–Present

Nuclear Power
Plant
FWS Species(c)
South Texas
whooping crane (Grus americana)
Limerick
bog turtle (Clemmys muhlenbergii)
Limerick
Limerick
Limerick
Grand Gulf
Grand Gulf
Grand Gulf
Grand Gulf

3-65

Grand Gulf
Grand Gulf
Grand Gulf
Grand Gulf

Callaway
Callaway
Callaway

NE

NMFS Species(c)
Atlantic sturgeon, New York Bight
DPS
shortnose sturgeon

Final Effect
Determination(d)
NE
NE

NE
NE

-

-

NLAA

none

-

NLAA
NE

-

-

NE

-

-

NLAA
NLAA
NE

-

-

NE

-

-

NE
NE
NLAA
NE
NLAA
NLAA
NE

none
-

-

NLAA
NLAA

-

-

NE

-

-

Affected Environment

NUREG-1437, Revision 2

Grand Gulf
Callaway
Callaway
Callaway
Callaway
Callaway
Callaway

Dwarf wedgemussel
(Alasmidonta heterodon)
Indiana bat (Myotis sodalis)
small whorled pogonia
(Isotria medeoloides)
American black bear
(Ursus americanus)
bayou darter (Etheostoma rubrum)
fat pocketbook mussel
(Potamilus capax)
least tern (Sterna antillarum), Interior
population
Louisiana black bear
pallid sturgeon (Scaphirhynchus albus)
rabbitsfoot mussel
(Quadrula cylindrica cylindrica)(g)
Red-cockaded woodpecker
(Picoides borealis)
wood stork (Mycteria americana)
gray bat (Myotis grisescens)
Indiana bat
Niangua darter (Etheostoma nianguae)
pallid sturgeon
pink mucket (Lampsilis abrupta)
running buffalo clover
(Trifolium stoloniferum)
scaleshell (Leptodea leptodon)
spectaclecase
(Cumberlandia monodonta)
Topeka shiner (Notropis topeka)

Final Effect
Determination(d)
NE
NE

3-66

Final Effect
Determination(d)
NE

NMFS Species(c)
none

Final Effect
Determination(d)
-

NLAA
NLAA

-

-

NE
NLAA

-

-

NLAA

-

-

NLAA
NE

none

-

NE
NE
NE

-

-

NE
NE

-

-

NE
NE
NE
NE
NE
NE
NE
NE
NE
NE

none
-

-

Affected Environment

NUREG-1437, Revision 2

Nuclear Power
Plant
FWS Species(c)
Davis-Besse
eastern prairie fringed orchid (Platanthera
leucophaea)
Davis-Besse
Indiana bat
Davis-Besse
Kirtland’s warbler
(Setophaga kirtlandii)(h)
Davis-Besse
lakeside daisy (Hymenopsis herbacea)
Davis-Besse
northern long-eared bat
(Myotis septentrionalis)
Davis-Besse
piping plover, Great Lakes watershed
population
Davis-Besse
rufa red knot (Calidris canutus rufa)(g)
Sequoyah
dromedary pearlymussel
(Dromus dromas)
Sequoyah
gray bat
Sequoyah
Indiana bat
Sequoyah
large-flowered skullcap
(Scutellaria montana)
Sequoyah
northern long-eared bat
Sequoyah
orangefoot pimpleback
(Plethobasus cooperianus)
Sequoyah
pink mucket
Sequoyah
rough pigtoe (Pleurobema plenum)
Sequoyah
small whorled pogonia
Sequoyah
snail darter (Percuba tanasi)
Sequoyah
Virginia spirarea (Spiraea virginiana)
Byron
eastern prairie fringed orchid
Byron
Indiana bat
Byron
leafy prairie clover (Dalea foliosa)
Byron
northern long-eared bat
Byron
prairie bush clover
(Lespedeza leptostachya)

3-67

Final Effect
Determination(d)
NE

NMFS Species(c)
none

Final Effect
Determination(d)
-

NE
NE

-

-

NE
NE
NE
NE
NLAA

-

-

NE
NE
NLAA
NLAA
NE

none
-

-

NLAA
NE

-

-

NLAA
NE
NLAA
NE
NE

none

-

NE
NE
NE
NE
NE

-

-

Affected Environment

NUREG-1437, Revision 2

Nuclear Power
Plant
FWS Species(c)
Braidwood
eastern massasauga
(Sistrurus catenatus)(g)
Braidwood
eastern prairie fringed orchid
Braidwood
Hine’s emerald dragonfly
(Somatochlora hineana)
Braidwood
lakeside daisy
Braidwood
leafy prairie clover
Braidwood
Mead’s milkweed (Asclepias meadii)
Braidwood
northern long-eared bat
Braidwood
sheepnose mussel
(Plethobasus cyphyus)
Braidwood
snuffbox (Epioblasma triquetra)
Fermi
eastern massasauga(g)
Fermi
eastern prairie fringed orchid
Fermi
Indiana bat
Fermi
Karner blue butterfly
(Lycaeides melissa samuelis)
Fermi
northern long-eared bat
Fermi
northern riffleshell
(Epioblasma torulosa rangiana)
Fermi
piping plover
Fermi
rayed bean (Villosa fabalis)
Fermi
rufa red knot
Fermi
snuffbox
LaSalle
decurrent false aster
(Boltonia decurrens)
LaSalle
eastern prairie fringed orchid
LaSalle
Indiana bat
LaSalle
leafy prairie clover
LaSalle
northern long-eared bat
LaSalle
sheepnose mussel

Indian Point(a)
Indian Point(a)
River Bend
Waterford
Waterford
Waterford
Turkey Point(b)
Turkey Point(b)
Turkey Point(b)

3-68

Turkey Point(b)
Turkey Point(b)
Turkey Point(b)
Turkey Point(b)
Turkey Point(b)
Turkey Point(b)
Turkey Point(b)
Turkey Point(b)
Turkey Point(b)
Turkey Point(b)

FWS Species(c)

Indiana bat
northern long-eared bat
pallid sturgeon
gulf sturgeon
(Acipenser oxyrinchus desotoi)
pallid sturgeon
West Indian manatee
American alligator
American crocodile (Crocodylus acutus)
Bachman’s warbler
(Vermivora bachmani)
Bartram’s hairstreak butterfly
(Strymon acis bartrami)
beach jacquemontia
(Jacquemontia reclinata)
Blodgett’s silverbush
(Argythamnia blodgettii)
Cape Sable seaside sparrow
(Ammodramus maritimus mirabilis)
Cape Sable thoroughwort
(Chromolaena frustrata)
Carter’s mustard (Warea carteri)
Carter’s small-flowered flax
(Linum carteri carteri)
crenulate lead-plant
(Amorpha crenulata)
deltoid spurge
(Chamaesyce deltoidea deltoidea)
eastern indigo snake
(Drymarchon corais couperi)

Final Effect
Determination(d)
NE

NLAA
NLAA
NLAA
NE
NLAA
NE
N/A

NMFS Species(c)
Atlantic sturgeon, New York Bight,
Gulf of Maine, and Chesapeake
Bay DPSs
shortnose sturgeon
none
none

Final Effect
Determination(d)
LAA

LAA

NLAA

LAA
NE*

green sea turtle, North Atlantic and
South Atlantic DPSs
hawksbill sea turtle
leatherback sea turtle

NE*

loggerhead sea turtle(e)

NLAA

NE*

smalltooth sawfish, U.S. DPS

NLAA

NLAA
NLAA

NLAA

-

-

NE*

-

-

NLAA

-

-

NE*
NE*

-

-

NE*

-

-

NE*

-

-

LAA

-

-

Affected Environment

NUREG-1437, Revision 2

Nuclear Power
Plant
Indian Point(a)
bog turtle

3-69

Final Effect
Determination(d)
NE*

NMFS Species(c)
-

Final Effect
Determination(d)
-

NLAA

-

-

NLAA

-

-

NE*
NLAA

-

-

NE*

-

-

NE*

-

-

NLAA
NE*

-

-

NE*

-

-

NE*

-

-

NLAA

-

-

NE*
NE*

-

-

NLAA
NE*

-

-

NE*

-

-

NE*

-

-

NLAA

-

-

Affected Environment

NUREG-1437, Revision 2

Nuclear Power
Plant
FWS Species(c)
Turkey Point(b) Everglades bully
(Sideroxylon reclinatum austrofloridense)
(b)
Turkey Point
Everglades snail kite
(Rostrhamus sociabilis)
Turkey Point(b) Florida bonneted bat
(Eumops floridanus)
Turkey Point(b) Florida brickell-bush (Brickellia mosieri)
Turkey Point(b) Florida bristle fern
(Trichomanes punctatum floridanum)
(b)
Turkey Point
Florida grasshopper sparrow
(Ammodramus savannarum)
Turkey Point(b) Florida leafwing butterfly
(Anaea troglodyta floridalis)
Turkey Point(b) Florida panther (Puma concolor coryi)
Turkey Point(b) Florida pinelands crabgrass
(Digitaria pauciflora)
Turkey Point(b) Florida prairie-clover
(Dalea carthagenensis floridana)
Turkey Point(b) Florida scrub-jay
(Aphelocoma coerulescens)
(b)
Turkey Point
Florida semaphore cactus
(Consolea corallicola)
(b)
Turkey Point
Garber’s spurge (Chamaesyce garberi)
Turkey Point(b) ivory-billed woodpecker
(Campephilus principalis)
Turkey Point(b) Kirtland’s warbler(h)
Turkey Point(b) Miami blue butterfly
(Cyclargus thomasi bethunebakeri)
Turkey Point(b) Okeechobee gourd
(Cucurbita okeechobeensis okeechobeensis)
Turkey Point(b) pineland sandmat
(Chamaesyce deltoidea pinetorum)
(b)
Turkey Point
piping plover

3-70

Surry(b)
Peach
Bottom(b)
Peach
Bottom(b)
Peach
Bottom(b)
Peach
Bottom(b)
Peach
Bottom(b)
Peach
Bottom(b)
Peach
Bottom(b)
North Anna(b)
North Anna(b)
North Anna(b)
North Anna(b)

Final Effect
Determination(d)
N/A

NMFS Species(c)
-

Final Effect
Determination(d)
-

NE*
NLAA
NLAA
NE*

-

-

NE*
NE*
NE*
NLAA
NLAA
NLAA

Atlantic sturgeon, Chesapeake
Bay DPS
shortnose sturgeon
none

NLAA

Atlantic sturgeon, Chesapeake Bay DPS

NE

NLAA
-

bog turtle

NE

-

-

Chesapeake logperch (Percina bimaculata)(i)

LAA

-

-

Indiana bat

NLAA

-

-

northern long-eared bat

NLAA

-

-

rufa red knot

NE

-

-

shortnose sturgeon

NE

-

-

Atlantic pigtoe (Fusconaia masoni)
dwarf wedgemussel
green floater (Lasmigona subviridis)
James spineymussel (Pleurobema collina)

NE*
NE*
NE*
NE*

none
-

-

Affected Environment

NUREG-1437, Revision 2

Nuclear Power
Plant
FWS Species(c)
Turkey Point(b) puma (Puma concolor), all subspecies
except coryi
(b)
Turkey Point
red-cockaded woodpecker
Turkey Point(b) rufa red knot
Turkey Point(b) sand flax (Linum arenicola)
Turkey Point(b) Schaus swallowtail butterfly
(Heraclides aristodemus ponceanus)
Turkey Point(b) Small’s milkpea (Galactia smallii)
Turkey Point(b) Stock Island tree snail (Orthalicus reses)
Turkey Point(b) tiny polygala (Polygala smallii)
Turkey Point(b) West Indian manatee
Turkey Point(b) wood stork
Surry(b)
northern long-eared bat

Nuclear Power
Plant
North Anna(b)
North Anna(b)
Point Beach(b)
Point Beach(b)
Point Beach(b)
Point Beach(b)
Point Beach(b)
Point Beach(b)

FWS Species(c)
northern long-eared bat
small whorled pogonia
dwarf lake iris (Iris lacustris)
Hine’s emerald dragonfly
northern long-eared bat
piping plover
Pitcher’s thistle (Cirsium pitcheri)
rusty patched bumblebee (Bombus affinis)

Final Effect
Determination(d)
NLAA
NE*
NE*
NE*
NLAA
NLAA
NE*
NE*

NMFS Species(c)
none
-

Final Effect
Determination(d)
-

3-71

Affected Environment

NUREG-1437, Revision 2

DPS = distinct population segments; ESA = Endangered Species Act; FWS = U.S. Fish and Wildlife Service; LAA = likely to adversely affect; N/A = not applicable;
NE = no effect; NLAA = may affect but is not likely to adversely affect; NMFS = U.S. National Marine Fisheries Service; NRC = U.S. Nuclear Regulatory
Commission; SLR = subsequent license renewal.
(a) The evaluation of this species was a part of a review that supplemented the NRC’s Final Supplemental Environmental Impact Statement.
(b) This review evaluated a subsequent license renewal term.
(c) This table omits species that were candidates or proposed for Federal listing at the time of the NRC staff's review but for which the Services later determined
that listing was not warranted.
(d) The effect determinations provided here are the final determinations concerning each species that resulted from consultation with the Services. In some
cases, the Service’s letter of concurrence revised or amended the NRC staff’s original effect determinations for a given species. For certain species, the NRC
staff determined that the species was not present in the action area. Accordingly, potential effects to these species were not evaluated in detail because there
would be none. Effect determinations for these species are designated in this table as NE*.
(e) At the time the NRC staff performed its review, U.S. National Marine Fisheries Service had not yet designated distinct population segments for this species.
(f) At the time the NRC staff performed its review, this species was a candidate for Federal listing. The Services have now issued a proposed rule to list the
species.
(g) At the time the NRC staff performed its review, this species was a candidate species or was proposed for Federal listing. The Services have now issued a final
rule listing the species.
(h) This species has been delisted since the NRC staff performed its review.
(i) At the time the NRC staff performed its review, this species was under review for Federal listing. It remains under review at this time.
No entry has been denoted by “-”.
Sources: NRC 2015b, NRC 2013b, NRC 2014d, NRC 2014e, NRC 2014f, NRC 2015e, NRC 2015f, NRC 2015c, NRC 2015d, NRC 2016c, NRC 2016d,
NRC 2018e, NRC 2018c, NRC 2018d, NRC 2019c, NRC 2020f, NRC 2020g, NRC 2021g, NRC 2021f.

Affected Environment
In 2021, the NRC (2021f) evaluated the risk of piping plovers colliding with nuclear power plant
buildings and structures as part of the Point Beach SLR review. The staff found that tall
structures are unlikely to represent a unique collision hazard for this species based on its typical
flight behavior. For instance, Stantial and Cohen (2015) assessed flight heights of piping plovers
in New Jersey and Massachusetts during the 2012 and 2013 breeding seasons. The
researchers found that flight heights ranged from 2.3 to 34.5 ft (0.7 to 10.5 m) with a mean of
8.5 ft (2.6 m). Visually estimated flight heights ranged from 0.25 to 131 ft (0.25 to 40 m).
Because piping plovers fly relatively low to the ground, they are acclimated to navigating various
natural and human-made flight hazards, and tall structures on nuclear power plant sites are
unlikely to create an additional risk. Even in the case of wind turbines, which have moving
components, researchers found that collision hazards at five wind facilities in New England
during the piping plover breeding season—assuming constant turbine operation—ranged from
0.06 to 2.27 collisions per year for a single large turbine (41 m radius), 0.03 to 0.99 for a single
medium turbine (22.5 m radius), and 0.01 to 0.29 for a single small turbine (9.6 m radius)
(Stantial 2014). With respect to vehicle collision hazards, Stantial and Cohen (2015) determined
the average calculated flight speed of piping plovers to be 30.5 fps (9.3 m/s). The high speed at
which piping plovers can fly makes them unlikely to collide with nuclear power plant site
vehicles, especially given that posted speed limits are generally low throughout these sites. The
FWS (2021) concurred with these findings for Point Beach SLR.
3.6.3.2

Magnuson-Stevens Fishery Conservation and Management Act

Congress enacted the MSA in 1976 to foster long-term biological and economic sustainability of
the Nation’s marine fisheries. The MSA is a comprehensive, multi-purpose statute. Its key
objectives include preventing overfishing, rebuilding overfished stocks, increasing long-term
economic and social benefits, and ensuring a safe and sustainable supply of seafood. NOAA,
together with eight regional Fishery Management Councils established under the act, implement
the provisions of the MSA.
The MSA directs the Fishery Management Councils, in conjunction with NMFS, to designate
areas of EFH and to manage marine resources within those areas. EFH is defined as the
coastal and marine waters and substrate necessary for fish to spawn, breed, feed, or grow to
maturity (50 CFR 600.10). The NMFS further defines “waters,” “substrate,” and “necessary” at
50 CFR 600.10. EFH applies to federally managed finfish and shellfish (herein referred to as
“EFH species”). As of 2022, the Councils and NMFS have designated EFH for nearly
1,000 species at multiple life stages.
The Fishery Management Councils may also designate some EFH as habitat areas of particular
concern (HAPCs) if that habitat exhibits one or more of the following traits: rare, stressed by
development, possessing important ecological functions for EFH species, or especially
vulnerable to anthropogenic degradation. HAPCs can cover a specific location (e.g., an estuary
bank or a single spawning location) or cover habitat type that is found at many locations
(e.g., coral, nearshore nursery areas, or pupping grounds). HAPC designation does not convey
additional restrictions or protections on an area. The designation simply focuses on increased
scrutiny, study, or mitigation planning compared to surrounding areas because HAPCs
represent high-priority areas for conservation, management, or research and are necessary for
healthy ecosystems and sustainable fisheries. The Fishery Management Councils may,
however, restrict the use or possession of fishing gear types within HAPCs. The geographic
boundaries of HAPCs are subject to refinement through amendments, as research better
informs management decisions (NOAA 2020).

NUREG-1437, Revision 2

3-72

Affected Environment
Section 305(b) of the MSA contains interagency consultation requirements pertaining to Federal
agencies and their actions. Under MSA Section 305(b)(2), Federal agencies must consult with
NMFS for actions that may adversely affect EFH. Private actions with a Federal nexus, such as
construction and operation of facilities that involve Federal licensing or approval, are also
subject to consultation. Therefore, the NRC’s issuance of initial or subsequent renewed licenses
may trigger consultation requirements. Consultation pursuant to MSA Section 305(b) is
commonly referred to as “EFH consultation.”
EFH includes the substrate and benthic resources (e.g., submerged aquatic vegetation, shellfish
beds, salt marsh wetlands, etc.), as well as the water column and prey species. NMFS defines
“adverse effects” under the MSA as (50 CFR 600.810):
…any impact that reduces quality and/or quantity of EFH. Adverse effects may
include direct or indirect physical, chemical, or biological alterations of the waters
or substrate and loss of, or injury to, benthic organisms, prey species and their
habitat, and other ecosystem components, if such modifications reduce the quality
and/or quantity of EFH. Adverse effects to EFH may result from actions occurring
within EFH or outside of EFH and may include site-specific or habitat-wide impacts,
including individual, cumulative, or synergistic consequences of actions.
Further, in 50 CFR 600.815(a)(7), adverse effects on EFH resulting from prey loss are
described as follows:
Loss of prey may be an adverse effect on EFH and managed species because the
presence of prey makes waters and substrate function as feeding habitat, and the
definition of EFH includes waters and substrate necessary to fish for feeding.
Therefore, actions that reduce the availability of a major prey species, either through
direct harm or capture, or through adverse impacts to the prey species’ habitat that
are known to cause a reduction in the population of the prey species, may be
considered adverse effects on EFH if such actions reduce the quality of EFH.
Notably, EFH is assessed in terms of impacts on the habitat of the EFH species rather than on
the species itself. Therefore, the physical removal of habitat through cooling water withdrawals
is an impact on EFH, whereas impingement and entrainment are not. Continued operation of a
nuclear power plant during an initial LR or SLR term may cause the following adverse effects in
the area:
• physical removal of habitat through cooling water withdrawals,
• physical alteration of habitat through heated effluent discharges,
• chemical alteration of habitat through radionuclides and other contaminants in heated effluent
discharges,
• physical removal of habitat through maintenance dredging, and
• reduction in the prey base of the habitat.
EFH may occur at nuclear power plants located on or near estuaries, coastal inlets and bays,
and the ocean. The MSA applies to marine and diadromous species. Therefore, EFH is
generally not relevant for license renewal reviews of plants located on rivers well above the
saltwater interface or confluence with marine waters; plants located on freshwater lakes,
including the Great Lakes; or at plants that draw cooling water from human-made cooling ponds

3-73

NUREG-1437, Revision 2

Affected Environment
or canals that do not hydrologically connect to natural surface waters. One exception is in cases
where a plant draws cooling water from the freshwater portion of a river that is inhabited by
diadromous prey of EFH species with designated EFH downstream of the plant. By definition,
adverse effects may occur outside of EFH, and loss of prey may be an adverse effect (see
regulatory definitions above).
The Limerick plant in Pennsylvania is an example where prey loss was relevant to the license
renewal review although the plant itself is not located near designated EFH. Limerick withdraws
cooling water from the Schuylkill River and Perkiomen Creek and discharges heated effluent to
the Schuylkill River. In cases where the natural flow of Perkiomen Creek is not adequate to
supply cooling water to Limerick, the plant augments flow from the Delaware River to Perkiomen
Creek. Although these waterways do not contain designated EFH, they provide habitat for
anadromous fish consumed by several EFH species (bluefish [Pomatomus saltatrix],
windowpane flounder [Scophthalmus aquosus], summer flounder [Paralichthys dentatus], and
winter skate [Leucoraja ocellata]). These four species have designated EFH in the mixing zone
of the Delaware River downstream from the Limerick plant. Prey of these species, such as
Alosa species (e.g., American shad and river herring), spawn in freshwater and migrate to
marine waters as juveniles. During migration, individuals pass through areas of designated
EFH. Therefore, loss of Alosa individuals through impingement and entrainment at the Limerick
plant has the potential to affect the abundance of prey downstream in the mixing zone, which
could affect the quality of this EFH as feeding habitat. Based on this reasoning, NMFS
recommended that the NRC engage in EFH consultation during the license renewal review. The
NRC (2014b) prepared an EFH assessment that addressed these and other relevant effects.
The NRC staff concluded that the Limerick license renewal would have minimal adverse effects
on EFH for juveniles and adults of the four EFH species. Subsequently, NMFS (2014b) provided
the NRC with EFH conservation recommendations, and the NRC (2014g) responded to these
recommendations, which concluded EFH consultation.
The NRC staff also assessed prey loss for SLR of the Peach Bottom plant in Pennsylvania.
During that review, the NRC (NRC 2020g) found that SLR would have no direct effects on the
EFH of any species because no designated EFH is present in Conowingo Pond. All potential
adverse impacts on EFH would be limited to loss of prey for those EFH species that consume
anadromous prey species that migrate through Conowingo Pond. Anadromous prey fish, such
as Alosa species, have been rare in collections associated with Conowingo Pond aquatic
studies. None of the available studies or other information indicate that impingement,
entrainment, thermal effects, or indirect impacts on the habitat of prey species would be
noticeably affected as a result of SLR. Accordingly, no adverse effects on EFH would result
from loss of prey, and the NRC staff concluded that the proposed action would have no adverse
effects on the designated EFH for little skate, windowpane flounder, or winter skate.
Table 3.6-6 identifies EFH species and life stages whose EFH the NRC staff, in consultation
with NMFS, evaluated during initial LR and SLR environmental reviews conducted since
publication of the 2013 LR GEIS.9 During this period, EFH was relevant to six reviews, and the
9

Prior to the 2013 LR GEIS, the NRC assessed EFH as part of seven license renewal environmental
reviews: Oyster Creek (no longer operating); (2) Brunswick; (3) Pilgrim in Massachusetts (no longer
operating); (4) Vermont Yankee in Vermont (no longer operating); (5) Indian Point (no longer operating);
(6) Salem and Hope Creek; and (7) Crystal River in Florida (no longer operating). These are not
described in detail in the 2013 LR GEIS. See the plant-specific SEISs for more information about these
EFH consultations. The NRC has also prepared EFH assessments and conducted EFH consultation with
NMFS for extended power uprates at the Hope Creek (NRC 2007a) and St. Lucie (NRC 2012c) plants.

NUREG-1437, Revision 2

3-74

Affected Environment
NRC staff evaluated the EFH of 37 species among these reviews. Atlantic herring
(Clupea harengus), Atlantic butterfish (Peprilus triacanthus), summer flounder, winter flounder
(Pleuronectes americanus), and winter skate were the most prevalently evaluated EFH species.
In most cases, the NRC staff concluded that license renewal would result in no adverse effects
or minimal adverse effects on EFH. For two EFH species, silver hake (Merluccius bilinearis) and
winter flounder, the NRC concluded that license renewal would result in more than minimal but
less than substantial adverse effects. The NRC (2015b) made this determination for all life
stages of silver hake and larvae, juveniles, and adults of winter flounder as a result of the
Seabrook plant license renewal. This was based on the effects of impingement, entrainment,
and thermal effluents on these species’ habitat.
Table 3.6-6

Essential Fish Habitat Evaluated in License Renewal Reviews,
2013–Present

Nuclear Power
Plant
Seabrook
Seabrook
Seabrook
Seabrook
Seabrook
Seabrook
Seabrook
Seabrook
Seabrook
Seabrook
Seabrook
Seabrook
Seabrook
Seabrook
Seabrook
Seabrook
Seabrook
Seabrook
Seabrook
Seabrook
Seabrook
Seabrook
Seabrook
Seabrook
Seabrook
Seabrook
Seabrook
Seabrook
Seabrook
Seabrook
Seabrook

Species
American angler fish (Lophius americanus)
American angler fish
American plaice (Hippoglossoides platessoides)
Atlantic butterfish (Peprilus triacanthus)
Atlantic cod (Gadus morhua)
Atlantic cod
Atlantic halibut (Hippoglossus hippoglossus)
Atlantic halibut
Atlantic herring (Clupea harengus)
Atlantic mackerel (Scomber scombrus)
Atlantic mackerel
Atlantic sea scallop (Placopecten magellanicus)
Atlantic sea scallop
Atlantic surf clam (Spisula solidissima)
bluefin tuna (Thunnus thynnus)
haddock (Melanogrammus aeglefinus)
longfin inshore squid (Loligo pealei)
northern shortfin squid (Illex illecebrosus)
ocean pout (Macrozoarces americanus)
ocean pout
pollock (Pollachius virens)
red hake (Urophycis chuss)
redfish (Sebastes fasciatus)
redfish
scup (Stenotomus chrysops)
silver hake (Merluccius bilinearis)
summer flounder (Paralicthys dentatus)
windowpane flounder (Scopthalmus aquosus)
winter flounder (Pleuronectes americanus)
winter flounder
yellowtail flounder (Pleuronectes ferruginea)

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Life
Stage(s)(b)
E, L, J
A
J, A
E, L, J, A
E
L, J, A
E, L
J, A
J, A
E, A
L, J
E, L, A
J
J, A
A
J
J, A
J, A
E, L, A
J
J
E, L, J, A
L
J, A
J, A
E, L, J, A
A
J, A
E
L, J, A
J, A

Final Effect
Determination(c)
MAE
NAE
NAE
NAE
NAE
MAE
NAE
MAE
MAE
MAE
NAE
NAE
MAE
NAE
NAE
NAE
NAE
NAE
NAE
MAE
MAE
MAE
NAE
MAE
NAE
LSA
MAE
MAE
NAE
LSA
MAE

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Nuclear Power
Plant
Columbia
Columbia
Limerick
Limerick
Limerick
Limerick
Limerick
Limerick
Limerick
Limerick
Limerick
Limerick
Turkey Point(a)
Turkey Point(a)
Turkey Point(a)
Turkey Point(a)
Turkey Point(a)
Surry(a)
Surry(a)
Surry(a)
Surry(a)
Surry(a)
Surry(a)
Surry(a)
Surry(a)
Surry(a)
Surry(a)
Peach Bottom(a)
Peach Bottom(a)
Peach Bottom(a)
Peach Bottom(a)
Peach Bottom(a)
Peach Bottom(a)

Species
coho salmon (Oncorhynchus kisutch)
Upper Columbia River Chinook salmon
(Oncorhynchus tshawytscha)
American plaice
Atlantic butterfish
Atlantic herring
black sea bass (Centropristus striata)
bluefish (Pomatomus saltatrix)
scup
summer flounder
windowpane flounder
winter flounder
winter skate (Leucoraja ocellata)
gray snapper (Lutjanus griseus)
mutton snapper (Lutianus analis)
pink shrimp (Farfantepenaeus duorarum)
spiny lobster (Panulirus argus)
white grunt (Haemulon plumieri)
Atlantic butterfish
Atlantic herring
black sea bass
bluefish
clearnose skate (Raja eglanteria)
little skate (Urophycis chuss)
red hake
summer flounder
windowpane flounder
winter skate
Atlantic herring
clearnose skate
little skate
red hake
windowpane flounder
winter skate

Life
Stage(s)(b)
-

Final Effect
Determination(c)
MAE
MAE

J
J
J
J
J, A
J
J, A
J, A
J, A
J, A
J, A
J
A
J, A
J
(P)
L, J, A
J, A
(P)
J, A
J, A
E, L, J, A
A
A
J, A

NAE
NAE
NAE
NAE
MAE
NAE
MAE
MAE
MAE
MAE
NE
NE
NE
NE
NE
MAE
NAE
NAE
MAE
NAE
MAE
NAE
MAE
MAE
MAE
NE
NE
NAE
NE
NAE
NAE

(a) This review evaluated a subsequent license renewal term.
(b) Essential Fish Habitat (EFH) is designated by life stage. E = eggs; L = larvae; J = juveniles; A = adults; (P) = prey
of EFH species.
(c) The effect determinations provided here are the final determinations concerning each species that resulted
from consultation with the National Marine Fisheries Service. NE = no effect; NAE = no adverse effects;
MAE = minimal adverse effects; LSA = more than minimal but less than substantial adverse effects;
SAA = substantial adverse effects.
No entry has been denoted by “-”.
Sources: NRC 2015b, NRC 2012a, NRC 2014b, NRC 2019c, NRC 2020f, NRC 2020g.

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3.6.3.3

National Marine Sanctuaries Act

Congress enacted the NMSA in 1972 to protect areas of the marine environment that have
special national significance. The NMSA authorizes the Secretary of Commerce to establish the
National Marine Sanctuary System and designate sanctuaries within that system. ONMS is
charged with comprehensively managing this system, which includes 15 sanctuaries and the
Papahānaumokuākea and Rose Atoll marine national monuments, encompassing more than
600,000 square miles of marine and Great Lakes waters from Washington State to the Florida
Keys, and from Lake Huron to American Samoa. Within these areas, sanctuary resources
include any living or nonliving resource of a national marine sanctuary that contributes to the
conservation, recreational, ecological, historical, educational, cultural, archaeological, scientific,
or aesthetic value of the sanctuary. As of 2023, five additional sanctuaries are proposed for
designation. Figure 3.6-1 depicts the locations of designated and proposed marine sanctuaries
and marine national monuments. Maps of designated and proposed sanctuaries are available
at: https://sanctuaries.noaa.gov/about/maps.html.

Figure 3.6-1 National Marine Sanctuaries and Marine National Monuments.
Source: NOAA 2023b.
In 1992, Congress amended the NMSA to require interagency coordination. Pursuant to
Section 304(d) of the NMSA, Federal agencies must consult with ONMS when their proposed
actions are likely to destroy, cause the loss of, or injure a sanctuary resource. Private actions
with a Federal nexus, such as construction and operation of facilities that involve Federal
licensing or approval, are also subject to consultation. Therefore, the NRC’s issuance of initial or
subsequent renewed licenses may trigger consultation requirements. Consultation pursuant to
NMSA Section 304(d) is commonly referred to as “NMSA consultation.”
Currently, five operating nuclear power plants are located near designated or proposed national
marine sanctuaries (see Table 3.6-7). Notably, this is a snapshot; the geographic extent of
existing sanctuaries may change or expand in the future, and NOAA is likely to designate new
sanctuaries as additional areas of conservation need are identified and assessed. National
marine sanctuary advisory councils, which are community-based advisory groups, actively help

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ONMS determine whether additional areas warrant statutory protection. For instance, the
advisory council for the Flower Garden Banks National Marine Sanctuary coordinated with
ONMS to recommend expanding this sanctuary to include certain sensitive underwater features
and marine biodiversity hotspots in the northwestern Gulf of Mexico. In 2021, NOAA published a
final rule that added 14 additional shelf-edge reefs and banks off the coasts of Texas and
Louisiana to this sanctuary (86 FR 4937). The Wisconsin Shipwreck Coast National Marine
Sanctuary in western Lake Michigan is also a recent designation. NOAA designated this
sanctuary in 2021 (86 FR 45860). As described further below, the Point Beach plant is located
near this sanctuary.
Table 3.6-7

National Marine Sanctuaries Near Operating Nuclear Power Plants

Sanctuary Name

Location

Nearby Nuclear
Power Plants

Lake Ontario(a)

Eastern Lake Ontario and a segment of the
Thousand Islands region of the St. Lawrence River

Ginna, Nine Mile
Point, FitzPatrick

Wisconsin Shipwreck Coast

Western Lake Michigan bordering Wisconsin

Point Beach

Florida Keys

Florida Keys from south of Miami westward to
encompass the Dry Tortugas, excluding Dry
Tortugas National Park

Turkey Point

(a) This sanctuary is currently proposed for designation.

The NRC staff has evaluated the potential impacts of license renewal on national marine
sanctuaries in two environmental reviews conducted since publication of the 2013 LR GEIS for
the Turkey Point and Point Beach plants, both of which were SLRs. These reviews are
summarized below; neither ultimately required NMSA consultation with ONMS.
The Florida Keys National Marine Sanctuary encompasses 2,900 nautical mi2 (5,370 nautical
km2) of coastal and ocean waters and submerged land surrounding the Florida Keys from south
of Miami westward and encompassing the Dry Tortugas. The sanctuary includes several unique
habitats, including the Nation’s only coral reef that lies adjacent to the continent and one of the
largest seagrass communities in the hemisphere. Card Sound, which lies adjacent and east of
the Turkey Point site, is within the boundaries of the sanctuary. In 2019, the NRC staff
determined that the Turkey Point SLR would not affect the resources of this sanctuary
(NRC 2019c). Available monitoring data indicated no discernable impact of Turkey Point plant’s
CCS on the ecology of surrounding marsh and mangrove areas, Biscayne Bay, Card Sound, or
any other nearby surface waters. The staff found that any potential future impacts would be
addressed and mitigated through State and county requirements concerning the CCS and
groundwater quality. Accordingly, the NRC staff concluded that SLR was not likely to destroy,
cause the loss of, or injure any sanctuary resources and that consultation under the NMSA was
not required.
The Wisconsin Shipwreck Coast National Marine Sanctuary encompasses a 962 mi2
(1,550 km2) area of western Lake Michigan along the Wisconsin coast. The sanctuary protects
shipwrecks that possess exceptional historic, archaeological, and recreational value. Rock reefs
and the structures of the shipwrecks provide shelter and foraging habitat for many species of
commercially and recreationally important fish. The sanctuary also includes the State-managed
Southern Refuge and the largest spawning population of lake trout (Salvelinus namaycush). The
Point Beach plant lies on the coast of Lake Michigan within the region designated for this
sanctuary. In 2021, the NRC staff determined that the Point Beach SLR would not affect the

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resources of this sanctuary (NRC 2021f). The NRC staff found that the sanctuary resources of
concern (a nationally significant collection of maritime cultural heritage resources, including
36 known shipwrecks) are located at least 2 mi (3.2 km) from the Point Beach site and beyond
the influence of either Point Beach’s cooling water intake structure or the area affected by
thermal effluent discharges and, thus, continued operation of Point Beach plant would not affect
these resources. The licensee did not plan to conduct any shoreline stabilization or other
in-water work during the proposed SLR term. Accordingly, the NRC staff concluded that
subsequent license renewal was not likely to destroy, cause the loss of, or injure any sanctuary
resources and that consultation under the NMSA was not required.

3.7
3.7.1

Historic and Cultural Resources
Scope of Review

Historic and cultural resources vary widely from site to site; there is no generic way of
determining their existence or significance. Historic and cultural resource impacts must be
analyzed on a plant-specific basis, and the NRC is required to complete a NEPA (42 U.S.C.
§ 4321 et seq.) and National Historic Preservation Act (NHPA) Section 106 review (54 U.S.C.
§ 300101 et seq.) prior to issuing a renewed license. This section presents an overview of these
resources and the NEPA and NHPA Section 106 review and consultation processes. Historic
and cultural resources are the remains of past human activities and include precontact
(i.e., prehistoric) and historic era archaeological sites, districts, buildings, structures, and
objects. Precontact era archaeological sites pre-date the arrival of Europeans in North America
and may include small temporary camps, larger seasonal camps, large village sites, or
specialized-use areas associated with fishing or hunting or with tool and pottery manufacture.
Historic era archaeological sites post-date European contact with Indian Tribes and may include
farmsteads, mills, forts, residences, industrial sites, and shipwrecks. Architectural resources
include buildings and structures. Historic and cultural resources also include elements of the
cultural environment such as landscapes, sacred sites, and other resources that are of religious
and cultural importance to Indian Tribes,10 such as traditional cultural properties important to a
living community of people for maintaining its culture.11
A historic or a cultural resource is deemed to be historically significant, and thus, a “historic
property” within the scope of the NHPA if it has been determined to be eligible for listing or is
listed on the National Register of Historic Places (NRHP).12 The NRHP is maintained by the
U.S. National Park Service in accordance with its regulations in 36 CFR Part 60. The NRHP

10

Per 36 CFR 800.2(c)(2)(ii), the agency official will consult with any Indian Tribe or Native Hawaiian
organization that attaches religious and cultural significance to historic properties that may be affected by
an undertaking.
11
According to U.S. National Park Service guidance, a “traditional cultural property” is associated “with
the cultural practices or beliefs of a living community that (a) are rooted in that community’s history and
(b) are important in maintaining the continuing cultural identity of the community” (Parker and King 1998).
12 Historic property is defined in 36 CFR 800.16(l)(1) as “... any prehistoric or historic district, site, building,
structure, or object included in, or eligible for inclusion in, the [NRHP] maintained by the Secretary of
Interior. This term includes artifacts, records, and remains that are related to and located within such
properties.” As defined in 36 CFR 800.16(l)(2), “The term eligible for inclusion in the National Register
includes both properties formally determined as such in accordance with regulations of the Secretary of
the Interior and all other properties that meet National Register listing criteria.”

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criteria to evaluate the eligibility of a property are set forth in 36 CFR 60.4.13 In this regard, a
historic property is at least 50 years old, although exceptions can be made for properties
determined to be of “exceptional significance.”14
3.7.2

NEPA and NHPA

NEPA requires Federal agencies to consider the potential effects of their actions on the affected
human environment, which includes “aesthetic, historic, and cultural resources as these terms
are commonly understood, including such resources as sacred sites” (CEQ and ACHP 2013).
For NEPA compliance, impacts on cultural resources that are not eligible for or listed in the
NRHP would also need to be considered (CEQ and ACHP 2013). The Advisory Council on
Historic Preservation is an independent Federal agency that oversees the NHPA Section 106
review process in accordance with its implementing regulations in 36 CFR Part 800, “Protection
of Historic Properties” (36 CFR Part 800). Section 106 of the NHPA requires Federal agencies
to take into account the effects of their undertakings15 on historic properties and consult with the
appropriate parties as defined in 36 CFR 800.2. Consulting parties include the State Historic
Preservation Officer (SHPO), Advisory Council on Historic Preservation, Tribal Historic
Preservation Officer, Indian Tribes that attach cultural and religious significance to historic
properties, and other parties that have a demonstrated interest in the effects of the undertaking,
including local governments and the public, as applicable. Issuing a renewed license (initial LR
or SLR) is a Federal undertaking that requires compliance with the NHPA Section 106.
When preparing plant-specific supplements to this LR GEIS (see 36 CFR 800.8(c)), the NRC’s
practice is to fulfill the requirements of NHPA Section 106 through the NEPA review process.
For each application, the NRC would identify consulting parties and determine the scope of
potential effects from the undertaking by defining the area of potential effects (APE). The license
renewal (initial LR or SLR) APE includes lands within the nuclear power plant site boundary and
the transmission lines up to the first substation that may be directly (e.g., physically) affected by
land-disturbing or other operational activities associated with continued plant operations and
maintenance and/or refurbishment activities. The APE may extend beyond the nuclear plant site
when these activities may indirectly (e.g., visual and auditory) affect historic properties. This
determination is made irrespective of land ownership or control.
The NRC will rely on historic and cultural resource investigations completed by qualified
professionals, who meet the Secretary of Interior’s standards at 36 CFR Part 61, to identify
historic and cultural resources located within the APE and complete NRHP eligibility
determinations in consultation with the SHPO and other consulting parties to determine whether
historic properties are present in the APE. The NHPA requires that information about the
locations of some historic and cultural resources, as well as sensitive sacred and religious
13

The eligibility of a resource for listing in the NRHP is evaluated based on four criteria and is articulated
in 36 CFR 60.4, as follows: Criterion a: Associated with events that have made a significant contribution
to broad patterns of our history; Criterion b: Associated with the lives of persons significant in our past; or
Criterion c: Embodies the distinctive characteristics of a type, period, or method of construction, or
represents the work of a master, or that possesses high artistic values, or that represents a significant
and distinguishable entity whose components may lack individual distinction; and Criterion d: Has yielded,
or is likely to yield, information important to prehistory and history.
14
36 CFR 60.4(g).
15
An undertaking is “a project, activity, or program funded in whole or in part under the direct or indirect
jurisdiction of a Federal agency, including those carried out by or on behalf of a Federal agency; those
carried out with Federal financial assistance; and those requiring a Federal permit, license or approval”
(see 36 CFR 800.16(y)).

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information, be withheld from the public to protect the resources (36 CFR 800.11(c)(1)). Other
legal authorities regarding protection of information from public release may also apply.
Additional historic and cultural resource laws could apply if a proposed project is located on
Federal lands (see Appendix F).
3.7.3

Historic and Cultural Resources at Nuclear Power Plant Sites

Nuclear power plant sites tend to be located in areas of focused past human activities (along
waterways) and, as such, there is a potential for historic and cultural resources to be present
within existing nuclear power plant site boundaries. A review of historic and cultural resources at
various nuclear power plants that have undergone initial LR or SLR since 2013 indicates that
there are a variety of historic and cultural resources (mainly archaeological resources) that
reflect land use throughout precontact and historic time periods. For example, at one nuclear
power plant site there were 129 historic and cultural resources identified within the site
boundaries, while other plant sites had fewer or no historic and cultural resources identified. The
number and diversity of resource types is dependent upon geographic location and prior site
land use.
Based on experience from initial LR and SLR environmental reviews, ground-disturbing
activities that occurred during nuclear power plant construction resulted in extensive disturbance
to much of the land in and immediately surrounding the power block. The term “power block”
refers to the buildings and components directly involved in generating electricity at a power
plant. At a nuclear power plant, the components of the power block vary with the reactor design,
but always include the reactor and turbine building, and usually include several other buildings
that include access, reactor auxiliary, safeguards, waste processing, or other nuclear generation
support functions. Buildings within the power block require significant excavation of existing
material, followed by placement of structural fill for a safe and stable base. Building excavations
are extensive, and the area of excavation is larger than the as-built power block and reactor
containment. There are also less-developed and undeveloped areas at nuclear power plant
sites, including areas that were not extensively disturbed (e.g., construction laydown areas).
Laydown areas are lands that were cleared, graded, and used to support fabrication and
installation activities during initial power plant construction. Intact archaeological resources are
unlikely to be present in heavily disturbed areas and do not require field investigation, whereas
less disturbed areas could still contain unrecorded archaeological resources and should be
investigated for the presence of historic and cultural resources.
Many nuclear power plant facilities were constructed prior to the implementation of NHPA
Section 106 regulations located at 36 CFR Part 800; therefore, there were no formal standards
for archaeological field investigations or requirements to identify and consult with Indian Tribes.
A review of historic and cultural resources at various nuclear power plants that have undergone
license renewal (initial LR or SLR) since 2013 indicates that most existing nuclear power plants
in the United States were not investigated prior to initial construction for the presence of
archaeological, architectural or traditional cultural properties resources, nor have Indian Tribes
been consulted regarding historic and cultural resources that may have significance to a Tribe’s
history, culture, or religion. In some cases, archaeological and architectural resource
investigations were completed prior to construction, but the methods used then are unlikely to
meet the current Secretary of Interior’s standards for archaeological and architectural resource
investigation. Historic and cultural resource field investigations may be necessary at the time of
initial LR and SLR if none were completed previously or may need to be updated to meet
current standards. In addition, identification of and consultation with Indian Tribes that have

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cultural and religious ties to nuclear power plant sites are required to identify all historic and
cultural resources that may be located within the APE. Identification of and consultation with
Indian Tribes is the responsibility of the NRC.
For example, during the license renewal review of the Sequoyah Nuclear Plant (Sequoyah),
Units 1 and 2, during the environmental audit, the NRC determined that a mound site that was
thought to have been destroyed by initial facility construction was partially intact. The mound
site was originally recorded in 1913 and excavated in 1936 and 1973. In 2010, Tennessee
Valley Authority (TVA) conducted a cultural resources survey in preparation for its license
renewal application. The survey was unable to locate the mound site and presumed that the site
no longer existed. TVA’s environmental report stated that the mound was destroyed during the
construction of Sequoyah Units 1 and 2. As a result of the NRC environmental audit and after
further discussions, TVA reopened its NHPA Section 106 consultation with the Tennessee
SHPO and submitted revisions to its previous cultural resource surveys and prepared an
updated site form for the mound site. Additionally, TVA also reinitiated NHPA Section 106
consultation with Indian Tribes. There was no formal eligibility determination of the site for listing
in the NRHP, although TVA believes the site is eligible (NRC 2015f).
Most license renewals are granted for a period of 20 years, so it is possible for historic and
cultural resources, including the nuclear power plant facility itself, to fall within the 50-year
threshold for inclusion in the NRHP and to have achieved historic significance during the license
renewal period. For example, Fermi plant Unit 1, the Nation’s first commercial-size nuclear
power plant was determined eligible for listing in the NRHP in 2012 (NRC 2016c). Due to the
passage of time since initial licensing, documentation and NRHP eligibility evaluation of all
historic and cultural resources that fall within the 50-year threshold should be completed for
initial LR and SLR.

3.8

Socioeconomics

This section describes socioeconomic factors that have the potential to be directly or indirectly
affected by changes in nuclear power plant operations. The nuclear plant and the communities
that support it can be described as a dynamic socioeconomic system. The communities provide
the people, goods, and services needed to operate the nuclear power plant. Power plant
operations, in turn, provide employment and income and pay for goods and services from the
communities. The measure of a community’s ability to support power plant operations depends
on the ability of the community to respond to changing economic conditions.
The socioeconomics region of influence is defined by the counties where nuclear power plant
employees and their families reside, spend their income, and use their benefits, thereby
affecting economic conditions in the region. Changes in power plant operation affects
socioeconomic conditions in the region of influence, including employment and income,
recreation and tourism, tax revenue, community services and education, population and
housing, and transportation.
3.8.1

Power Plant Employment and Expenditures

Nuclear power plants generate employment and income in the local economy. Wages, salaries,
and expenditures generated by nuclear plant operation create demand for goods and services
in the local economy, while wage and salary spending by workers creates additional demand for
services and housing. Nuclear power plants also provide tax revenue for education, public
safety, government services, and transportation.

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Employment at nuclear power plants varies based on a number of factors, including the number
of reactor units, energy production, and the type and age of the nuclear plant. The review of
annual economic data on 15 nuclear power plants shows employment at these nuclear plants
averaged about 800 workers, ranging from 506 workers at Point Beach to 941 workers at the
Surry plant (Table 3.8-1).
Table 3.8-1

Local Employment and Tax Revenues at 15 Nuclear Plants from 2014
through 2020

Nuclear Power
Plant
Byron
Braidwood
Comanche Peak
Fermi
Ginna
South Texas
LaSalle
Cooper
Waterford
River Bend
Turkey Point
Surry
Peach Bottom
North Anna
Point Beach

Data Year
2013
2014
2014
2014
2014
2014
2015
2016
2016
2017
2018
2018
2019
2020
2020

Percent of Local
Employment
0.50
0.22
N/A
0.12
N/A
N/A
0.22
N/A
0.27
0.31
0.05
4.60
0.19
2.69
0.30

Employment
867
885
889
889
889
680
889
641
641
680
679
941
919
903
506

Tax
Revenues
($ million)
33.0
24.5
70.0
19.6
10.0
70.0
22.5
N/A
22.4
14.2
36.6
13.3
1.4
11.6
10.2

Percent of
Local Tax
Revenue
28.3
1.4
N/A
43.7
N/A
N/A
31.1
N/A
15.2
63.1
0.4
61.3
0.8
4.8
2.8

N/A = not available.
Sources: NRC 2015c, NRC 2016d, NRC 2016c, NRC 2018c, NRC 2018d, NRC 2019c, NRC 2020g, NRC 2020f,
NRC 2021f, NRC 2021g, NEI 2015b, NEI 2015c, NEI 2018, NEI 2015a.

Nuclear power plants provide tax revenue to State and local governments, and the 15 nuclear
plants evaluated have tax characteristics similar to those in the 2013 LR GEIS. State and local
tax payments ranged from $1.4 million at the Peach Bottom plant to $70.0 million at both the
South Texas Project Electric Generating Station (South Texas) plant and Comanche Peak
Nuclear Power Plant (Comanche Peak), averaging $25.3 million. Differences in tax revenue
generated by the nuclear power plants are due to differences in State and local tax laws,
electricity output, plant size, and plant employment.
Additional employment and expenditures occur during refueling and maintenance outages at
each nuclear power plant, when additional workers and services are required for a 1- to 2-month
period. Refueling outages generally occur on an 18- to 24-month cycle.
3.8.2

Regional Economic Characteristics

Regional economic characteristics can vary depending on the location of the nuclear power
plant. Socioeconomic conditions in the county where the nuclear plant is located are directly
affected by power plant operations as are the counties where the majority of power plant
workers reside.

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Many areas have changed since the nuclear power plant was constructed. Residential and
commercial development and the diversification of economic activity in these areas have also
changed the local and regional economic profile. Outdoor recreational activities have changed
the focus of local and regional economic activity, and the growth of retirement communities, in
some instances, rivals the importance of traditional economic activities in the vicinity of a
nuclear power plant.
As previously discussed, nuclear power plant operations generate employment, income,
and expenditures in the local economy. These expenditures—payments for goods and
services—create additional opportunities for employment and income in the regional economy.
Nuclear plants are located in one of two regional economic settings: rural or urban.
3.8.2.1

Rural Economies

Most nuclear power plants are located in rural areas, where agriculture is the primary economic
activity. Rural areas are considered to have relatively simple economies, without industries that
provide the equipment and services needed to support nuclear plant operations, and with
smaller, less diversified labor markets. A range of other industrial activities, including those
associated with resource extraction, manufacturing, and transportation, provide employment
and income.
Nuclear power plants located in rural economies include the Byron, River Bend, Waterford
Steam Electric Station (Waterford), Surry, North Anna Power Station (North Anna), Point Beach,
R.E. Ginna Nuclear Power Plant (Ginna), Comanche Peak, South Texas, and Cooper plants.
Only 2 of the 10 nuclear plants, Surry and North Anna, provided 1 percent or more to regional
employment.
3.8.2.2

Urban Economies

Some nuclear power plants are located in or near urban areas that have more complex
economic activities, a wider range of industries, and larger and more diverse labor markets.
Urban areas may also serve more specialized economic functions, including maritime shipping,
fishing, and boatbuilding; recreation; and tourism. Many also have residential areas with second
homes and retirement communities.
Nuclear power plants located in urban economies include the Braidwood, Fermi, LaSalle,
Turkey Point, and Peach Bottom plants. None of the nuclear plants provided 1 percent or more
to regional employment.
3.8.3

Demographic Characteristics

Although most nuclear power plants are situated in rural areas, population densities within 20 mi
(50 km) of most nuclear plant sites are generally high, and most are within 50 mi (80 km) of a
city with a population of at least 100,000 (see Appendix C). Demographics vary around each
nuclear power plant, and many are affected by the remoteness of the nuclear plant to regional
population centers.
Two measures of remoteness were developed for the LR GEIS—“sparseness” and
“proximity”—which combine demographic data on population density and the distance to larger
cities to place nuclear plants into three population classes (1996 LR GEIS). Population
classifications of 15 representative nuclear power plant sites are presented in Table 3.8-2.

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Table 3.8-2

Population Classification of Regions around Selected Nuclear Power Plants

Nuclear Power
Population
Plant
Low
Cooper
Low
South Texas
Low
River Bend
Moderate
Comanche Peak
Moderate
Byron
High
North Anna
High
Point Beach
High
LaSalle
High
Waterford
High
Braidwood
High
Surry
High
Turkey Point
High
Peach Bottom
High
Fermi
High
Ginna

Population
Density Within
20 miles
12.9
40.1
105.7
70.5
220.1
149.1
226.9
253.2
438.8
486.8
531.3
937.3
1,268.5
1,486.7
3,339.3

Sparseness
Measure
1
2
3
3
4
4
4
4
4
4
4
4
4
4
4

Population
Density Within
50 miles
19.7
42.8
137.0
269.4
165.3
296.3
298.0
250.9
353.2
655.8
427.2
685.4
874.8
788.2
335.7

Proximity
Measure
1
1
3
4
3
4
4
4
4
4
4
4
4
4
4

Source: Pacific Northwest National Laboratory calculations based on 2020 decennial census data.

Many communities near a nuclear power plant have transient populations attracted to tourism
and recreational activities, weekend and summer homes, and students attending full-time
colleges and other educational institutions. Nuclear power plants located in coastal regions,
notably D.C. Cook and Palisades plants on Lake Michigan and Brunswick plant on the
North Carolina coast between Wilmington, North Carolina, and Myrtle Beach, South Carolina,
have weekend, summer, and retirement populations and a range of recreational amenities that
attract visitors from nearby metropolitan areas.
In addition to transient populations, farms and factories in rural communities often employ
migrant workers on a seasonal basis. For example, berry production near the D.C. Cook and
Palisades plants is a local agricultural activity that employs a sizable migrant labor force in the
summer.
3.8.4

Housing and Community Services

Housing in the vicinity of nuclear power plants ranges in the number of housing units and the
type and quality of available housing. Much of the difference is due to the local economy,
population, and income; proximity to metropolitan areas; and recreation, tourism, second
homes, and retirement communities. Although housing demand can be affected by changes in
the number of workers at a nuclear power plant, demand for temporary rental housing increases
during refueling and maintenance outages. This demand affects the availability and cost of
housing. Some workers may occupy motel rooms and other temporary accommodations during
refueling outages, which include onsite temporary housing at some nuclear power plants.
Rural communities have smaller housing markets, stable prices for most types of housing, lower
median house values, and stable vacancy rates. Housing markets in urban areas are generally
less stable and feature more turnover, higher prices, and lower vacancy rates. Controls on
housing development are more likely in urban areas, particularly where there is a transient
seasonal population.

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Sparseness and Proximity Measures
Sparseness
Most Sparse
1. There are fewer than 40 people/mi2 (15 people/km2) and there is no community with
25,000 or more people within 20 mi (32 km) of the plant.
2. There are 40 to 60 people/mi2 (15 to 23 people/km2) and there is no community with
25,000 or more people within 20 mi (32 km) of the plant.
3. There are 60 to 120 people/mi2 (23 to 46 people/km2) and there is at least one
community with more than 25,000 people/mi2 (10,000 people/km2) within 20 mi (32 km)
of the plant.
Least Sparse
4. There are more than 120 people/mi2 (46 people/km2) within 20 mi (32 km) of the plant.
Proximity
Not in Close Proximity
1. There are fewer than 50 people/mi2 (19 people/km2) and there is no city with more than
100,000 people within 50 mi (80 km) of the plant.
2. There are 50 to 190 people/mi2 (19 to 73 people/km2) and there is no city with 100,000
people within 50 mi (80 km) of the plant.
3. There are fewer than 190 people/mi2 (73 people/km2) and there are one or more cities
with more than 100,000 people within 50 mi (80 km) of the plant.
In Close Proximity
4. There are more than 190 people/mi2 (73 people/km2) within 50 mi (80 km) of the plant.
Source: Adapted from NUREG/CR-2239 (SNL 1982).

3.8.5

Tax Revenue

Nuclear power plants provide tax revenue to State and local governments. Although property
taxes are the most important source of revenue for most communities, other sources of revenue
include taxes on energy production and direct funding from Federal and State governments for
educational facilities and programs. Between 2014 and 2020, State and local taxes paid by the
15 nuclear power plants listed in Table 3.8-1 ranged from $1.4 million at the Peach Bottom plant
to $70 million at the South Texas and Comanche Peak plants, averaging $24.1 million.
Differences in tax revenue are due to variations in State and local tax laws, energy production,
power plant size, and employment. Tax revenue is also used by State, regional, and local
governments to fund education, public safety, services, and transportation networks. Property
taxes paid by nuclear power plant owners contribute more than 50 percent of total property tax
revenue in some rural communities (e.g., at the River Bend plant in Louisiana and the Surry
plant in Virginia). Loss of tax revenue can affect the quality and availability of public services.
The deregulation of electricity markets in some States has led to changes in the methods used
to estimate property values at some nuclear power plants. Any changes in tax revenues after
utility deregulation would not occur as a direct result of license renewal (initial LR or SLR).

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3.8.6

Local Transportation

Local and regional transportation networks in the vicinity of a nuclear power plant vary
considerably depending on population density, the location and size of communities, economic
development patterns, the power plant’s location relative to interregional transportation
corridors, and land surface features, such as mountains, rivers, and lakes. Commuting patterns
in the vicinity of a nuclear power plant depend on the extent to which these factors limit or
facilitate traffic movement and on the size of the workforce that uses the transportation network
at any given time. Traffic volumes near a nuclear power plant depend on road network capacity,
local traffic patterns, and the availability of alternate routes. Because most nuclear power plants
have only one access road, congestion on this road may occur during shift changes.

3.9

Human Health

3.9.1

Radiological Exposure and Risk

Radiological exposures from nuclear power plants include offsite doses to members of the
public and onsite doses to the workforce. Each of these impacts is common to all commercial
U.S. reactors. The AEA requires the NRC to promulgate, inspect, and enforce standards that
provide an adequate level of protection for public health and safety and the environment. The
NRC continuously evaluates the latest radiation protection recommendations from international
and national scientific bodies to establish the requirements for nuclear power plant licensees.
The NRC has established multiple layers of radiation protection limits to protect the public
against potential health risks from exposure to effluent discharges from nuclear power plant
operations. If the licensees exceed a certain fraction of these dose levels in a calendar quarter,
they are required to notify the NRC, investigate the cause, and initiate corrective actions within
the specified time frame. Section 3.9.1.1 discusses regulatory requirements at nuclear power
plants. Sections 3.9.1.2 and 3.9.1.3 discuss occupational and public exposure, respectively.
These sections evaluate the performance of licensees in implementing these requirements, and
they compare the doses and releases with permissible levels. Risk estimates are provided in
Section 3.9.1.4.
3.9.1.1

Regulatory Requirements

Nuclear power reactors in the United States must be licensed by the NRC and must comply with
NRC regulations and conditions specified in the license in order to operate. The licensees are
required to comply with 10 CFR Part 20, Subpart C, “Occupational Dose Limits for Adults,” and
10 CFR Part 20, Subpart D, “Radiation Dose Limits for Individual Members of the Public.”
3.9.1.1.1 Regulatory Requirements for Occupational Exposure
10 CFR 20.1201 establishes occupational dose limits (see Table 3.9-1).
Under 10 CFR 20.2206, the NRC requires licensees to submit an annual report of the results of
individual monitoring carried out by the licensee for each individual for whom monitoring was
required by 10 CFR 20.1502 during that year.

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Table 3.9-1

Occupational Dose Limits for Adults Established by 10 CFR Part 20

Tissue
Whole-body or any individual
organ or tissue other than the
lens of the eye
Lens of the eye
Extremities, including skin

Dose Limit(a)
More limiting of 5 rem/yr TEDE to whole-body or 50 rem/yr sum of
the deep dose equivalent and the committed dose equivalent to
any individual organ or tissue other than the lens of the eye
15 rem/yr dose equivalent
50 rem/yr shallow dose equivalent

CFR = Code of Federal Regulations; rem/yr = roentgen equivalent man/per year; TEDE = total effective dose
equivalent.
(a) See table below for definitions.
Note: To convert rem to sievert, multiply by 0.01.
Source: 10 CFR Part 20.

Definitions of Dosimetry Terms
• Total effective dose equivalent (TEDE): Sum of the dose equivalent (for external
exposure) and the committed effective dose equivalent (for internal exposure).
• Committed effective dose equivalent (CEDE): Sum of the products of the weighting
factors for body organs or tissues that are irradiated and the committed dose equivalent to
these organs or tissues.
• Deep dose equivalent: Applies to external whole-body exposure and is the dose equivalent
at a tissue depth of 1 cm.
• Committed dose equivalent: Dose equivalent to organs or tissues from an intake of
radioactive material for the 50-year period following the intake.
• Dose equivalent: Product of the absorbed dose in the tissue, quality factor, and all other
necessary modifying factors at the location of interest.
• Shallow dose equivalent: Applies to the external exposure of the skin, as the dose
equivalent at a tissue depth of 0.007 cm averaged over an area of 1 cm2.
• Organ dose: Dose received as a result of radiation energy absorbed in a specific organ.
• Total body dose or whole-body dose: Sum of the dose received from external exposure
to the total body, gonads, active blood-forming organs, head and trunk, or lens of the eye
and the dose due to the intake of radionuclides by inhalation and ingestion, where a
radioisotope is uniformly distributed throughout the body tissues rather than being
concentrated in certain parts.
Under 10 CFR 20.2202 and 10 CFR 20.2203, the NRC requires all licensees to submit reports
of all occurrences involving personnel radiation exposures that exceed certain control levels.
The control levels are used to investigate occurrences and to take corrective actions as
necessary. Depending on the magnitude of the exposure, the occurrence reporting is required
immediately, within 24 hours, or within 30 days. Based on the reporting requirement, the control
levels can be placed in one of three categories (A, B, or C), as follows (NRC 2020i, NRC 2022f):
• Category A, immediate notification. A TEDE of 25 rem or more to any individual, an eye dose
equivalent of 75 rem or more, or a shallow dose equivalent to the skin or extremities of
250 rad or more (10 CFR 20.2202(a)(1)).
• Category B, notification within 24 hours. A TEDE of 5 rem or more to any individual, an eye
dose equivalent of 15 rem or more, or a shallow dose equivalent to the skin or extremities of
50 rem or more (10 CFR 20.2202(b)(1)).

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• Category C, written report within 30 days. Any incident for which notification was required and
doses or releases that exceed the limits in the license set by the NRC or EPA
(10 CFR 20.2203).
3.9.1.1.2 Regulatory Requirements for Public Exposure
NRC regulations in 10 CFR Part 20 identify maximum allowable concentrations of radionuclides
that can be released from a licensed facility into the air and water above background levels at
the boundary of unrestricted areas to control radiation exposures of the public and releases of
radioactivity. These concentrations are derived based on an annual TEDE of 0.1 rem to
individual members of the public. In addition, pursuant to 10 CFR 50.36a, nuclear power
reactors have special license conditions called technical specifications for radioactive gaseous
and liquid releases from the plant that are required to minimize the radiological impacts
associated with plant operations to levels that are ALARA.
Appendix I to 10 CFR Part 50 provides numerical values on dose-design objectives for
operation of LWRs to meet the ALARA requirement. The design objective doses for Appendix I
are summarized here in Table 3.9-2.
In addition to keeping within NRC requirements, nuclear power plant releases to the
environment must comply with EPA standards in 40 CFR Part 190, “Environmental Radiation
Protection Standards for Nuclear Power Operations.” These standards specify limits on the
annual dose equivalent from normal operations of uranium fuel-cycle facilities (except mining,
waste disposal operations, transportation, and reuse of recovered non-uranium special nuclear
and by-product materials). The standards are given in Table 3.9-3. Radon and its daughters are
covered by Subpart D of 40 CFR Part 192 (the conforming NRC regulations are in Appendix A
of 10 CFR Part 40.
Table 3.9-2

Design Objectives and Annual Standards on Doses to the General Public
from Nuclear Power Plants(a) from Appendix I to 10 CFR 50

Tissue
Total body, mrem
Any organ (all pathways), mrem
Ground-level air dose,(b) mrad
Any organ(c) (all pathways), mrem
Skin, mrem

Gaseous Effluents
5(b)
N/A
10 (gamma) and 20 (beta)
15
15

Liquid Effluents
3
10
N/A
N/A
N/A

CFR = Code of Federal Regulations; mrem = millirem; mrad = millirad; N/A = not applicable.
(a) Calculated doses.
(b) The ground-level air dose has always been limiting because an occupancy factor cannot be used. The 5 mrem
total body objective could be limiting only in the case of high occupancy near the restricted area boundary.
(c) Particulates, radioiodines.
Source: 10 CFR Part 50.

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Table 3.9-3

Design Objectives and Annual Standards on Doses to the General Public
from Nuclear Power Plants(a) from 40 CFR 190, Subpart B

Tissue
mrem
Thyroid,(b) mrem
Any other organ,(b) mrem
Whole-body,(b)

Gaseous Effluents
25
75
25

Liquid Effluents
N/A
N/A
N/A

CFR = Code of Federal Regulations; mrem = millirem; N/A = not applicable.
(a) Calculated doses.
(b) All effluents and direct radiation except radon and its daughters.
Source: 40 CFR Part 190.

EPA standards in 40 CFR Part 61, “National Emission Standards for Hazardous Air Pollutants,”
apply only to airborne releases. The EPA specified an annual effective dose equivalent limit of
10 mrem for airborne releases from nuclear power plants; however, no more than 3 mrem can
be caused by any isotope of iodine. However, the EPA later rescinded Subpart I of 40 CFR
Part 61 as it applies to nuclear reactors based on the EPA’s determination that the NRC’s
regulations provide an ‘ample margin of safety’ (60 FR 46206).
Experience with the design, construction, and operation of nuclear power reactors indicates that
compliance with the design objectives of Appendix I to 10 CFR Part 50 will keep average annual
releases of radioactive material in effluents at small percentages of the limits specified in
10 CFR Part 20 and 40 CFR Part 190. At the same time, the licensee is given the flexibility in
operations, compatible with considerations of health and safety, to ensure that the public is
provided with a dependable source of power, even under unusual operating conditions that
might temporarily result in releases that were higher than such small percentages but still well
within the regulatory limits.
Another 10 CFR Part 20 requirement is that the sum of the external and internal doses (i.e., in
TEDE) for a member of the public shall not exceed 100 mrem/yr. This value is an annual limit
and is not intended to be applied as a long-term average goal. The dose limits in 10 CFR
Part 20 are based on the methodology described in International Commission on Radiological
Protection (ICRP) Publication 26 (ICRP 1977). The radiation levels at any unrestricted area
should not exceed 2 mrem in any one hour. As stated in 10 CFR 20.1302(b), licensees comply
with the 100-mrem limit for individual members of the public by (1) demonstrating by
measurement or calculation that the dose to the individual likely to receive the highest dose
from sources under the licensee’s control does not exceed the annual dose limit or (2) that the
annual average concentrations of radioactive material released in gaseous and liquid effluents
at the boundary of the unrestricted area do not exceed the levels specified in Table 2 of 10 CFR
Part 20, Appendix B and at the unrestricted area boundary, the dose from external sources
would not exceed 2 mrem in any given hour and 50 mrem in a single year. The concentration
values given in Table 2 of Appendix B to 10 CFR Part 20 are equivalent to the radionuclide
concentrations that, if inhaled or ingested continuously in a year, would produce a TEDE of
50 mrem. Nuclear power reactors, as discussed earlier in this section, are subject to additional
regulatory controls which maintain doses to members of the public to the ALARA dose-design
objectives in Appendix I to 10 CFR Part 50.
3.9.1.2

Occupational Radiological Exposures

This section provides an evaluation of the radiological impacts on nuclear power plant workers.
This evaluation extends to all nuclear power reactors. The data in this section are generally

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sourced from NUREG-0713 Volume 42 (NRC 2020i, NRC 2022f), which provides data through
2020. In 2020, there were 95 operating reactors in the United States, and all were LWRs;
among them 31 were BWRs and 64 were PWRs. Currently (as of August 2023), there are
92 operating reactors in the United States, and all are LWRs. Among them, 31 are BWRs and
61 are PWRs (NRC 2023f).16
Plant workers conducting activities involving radioactively contaminated systems or working in
radiation areas can be exposed to radiation. Individual occupational doses are measured by
NRC licensees as required by the basic NRC radiation protection standard, 10 CFR Part 20
(see Section 3.9.1.1). Most of the occupational radiation dose to nuclear plant workers results
from external radiation exposure rather than from internal exposure from inhaled or ingested
radioactive materials. Workers also receive radiation exposure during the storage and handling
of radioactive waste and during the inspection of stored radioactive waste. However, this source
of exposure is small compared with other sources of exposure at operating nuclear plants.
Table 3.9-4 shows the radiation exposure data from all commercial U.S. nuclear power plants
for the years 2006 through 2020. The year 2006 was chosen as a starting date because the
dose data for years before 2006 were presented in the 2013 LR GEIS and the 1996 LR GEIS.
For each year, the number of reactors, the number of workers receiving measurable exposures,
the collective dose for all reactors combined, and the number of individuals receiving a dose in
the range of 4 to 5 rem are given. The collective dose is the sum of all personal doses and is
expressed as person-rem. Data indicate that no worker received a dose in the range of 4 to
5 rem from 2006 to 2020. The collective dose has been about 11,000 person-rem or less since
2006 and shows a decreasing trend.
Table 3.9-4 Occupational Whole-Body Dose Data at U.S. Commercial Nuclear Power
Plants
Calendar
Year

Number of Workers
with Measurable Dose

Collective Dose
(person-rem)

Number of
Licensees

Number of Workers in
the Range of 4 to 5

2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019

80,265
79,530
79,450
81,754
75,010
81,321
79,549
67,236
70,847
70,798
59,353
64,761
61,014
53,615

11,021
10,120
9,196
10,025
8,631
8,771
8,035
6,760
7,125
7,019
5,366
6,417
5,829
5,081

104
104
104
104
104
104
104
100
100
99
99
99
98
96

0
0
0
0
0
0
0
0
0
0
0
0
0
0

16

This count does not include Vogtle Units 3 and 4, in Waynesboro, Georgia, which are new, large light
water reactors that commenced commercial operations in July 2023 and April 2024, respectively. The
scope of this revised LR GEIS is limited to nuclear power plants for which an operating license,
construction permit, or combined license was issued as of June 30, 1995.

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Calendar
Year
2020

Number of Workers
with Measurable Dose
52,820

Collective Dose
(person-rem)
4,899

Number of
Licensees
95

Number of Workers in
the Range of 4 to 5
0

Note: To convert rem to sievert (Sv), multiply by 0.01.
Source: NRC 2020i, NRC 2022f.

Table 3.9-5 and Table 3.9-6 show the occupational dose history (2006 to 2020) for all
commercial U.S. reactors. Average measurable occupational dose and annual collective
occupational dose information are presented for plants that operated between 2006 and 2020.
For the period from 2006 to 2020, the annual average measurable dose per plant worker has
shown decreasing trends for both PWRs and BWRs. During 2020, at all operating nuclear
power plants, the annual average individual dose was 0.09 rem compared with an exposure
limit of 5 rem. The average collective occupational exposure for the year 2020 was roughly
0.95 person-Sv (95 person-rem) per plant at BWRs and about 0.31 person-Sv (31 person-rem)
per plant at PWRs.
Table 3.9-7 and Table 3.9-8 show the 3-year collective dose per reactor, number of workers
with measurable doses, and average dose per worker for BWRs and PWRs, respectively, for
the years 2018 to 2020.
Deviations higher than these averages in the table are routinely experienced, depending largely
on whether a plant had an outage during a given year and the nature and extent of
refurbishment or repair activities undertaken during outages.
Table 3.9-5

Annual Average Measurable Occupational Dose per Individual for U.S.
Commercial Nuclear Power Plants in rem

Year

BWR

PWR

LWR

2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020

0.15
0.14
0.13
0.15
0.13
0.13
0.11
0.12
0.11
0.12
0.11
0.12
0.12
0.12
0.11

0.13
0.11
0.10
0.10
0.10
0.09
0.09
0.07
0.09
0.08
0.07
0.07
0.07
0.07
0.07

0.14
0.13
0.12
0.12
0.12
0.11
0.10
0.10
0.10
0.10
0.09
0.10
0.10
0.09
0.09

BWR = boiling water reactor; LWR = light water reactor; PWR = pressurized water reactor; rem = roentgen equivalent
man.
Source: NRC 2020i, NRC 2022f.

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Table 3.9-6

Annual Average Collective Occupational Dose for U.S. Commercial
Nuclear Power Plants in Person-rem

Year

BWR

PWR

LWR

2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020

143
154
129
151
137
142
120
127
109
122
98
118
111
105
95

87
69
68
69
55
55
56
35
51
44
31
37
34
27
31

106
97
88
96
83
84
77
68
71
71
54
65
59
53
52

BWR = boiling water reactor; LWR = light water reactor; PWR = pressurized water reactor; rem = roentgen equivalent
man.
Source: NRC 2020i, NRC 2022f.

Table 3.9-7

Collective and Individual Worker Doses at Boiling Water Reactors from
2018 through 2020

Nuclear Power Plant(a)
Browns Ferry 1, 2, 3
Brunswick 1, 2
Clinton
Columbia
Cooper Station
Dresden 2, 3
Fermi 2
FitzPatrick
Grand Gulf
Hatch 1, 2
Hope Creek 1
Lasalle 1, 2
Limerick 1, 2
Monticello
Nine Mile Point 1, 2
Peach Bottom 2, 3
Perry

Reactor
Years

Three-year Collective
TEDE per Reactor
Year 2018–2020
(person-rem)

Number of
Workers with
Measurable
TEDE

Average TEDE
per Worker
(rem)

9
6
3
3
3
6
3
3
3
6
3
6
6
3
6
6
3

131.739
94.291
83.287
84.075
80.225
73.929
318.338
134.964
143.189
60.440
111.963
140.158
65.853
59.818
132.619
85.875
120.692

8,735
4,687
2,710
2,133
2,211
6,042
6,695
3,017
4,877
3,864
3,125
7,315
4,978
1,577
4,807
5,005
1,641

0.136
0.121
0.092
0.118
0.109
0.073
0.143
0.134
0.088
0.094
0.107
0.115
0.079
0.114
0.166
0.103
0.221

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Nuclear Power Plant(a)
Quad Cities 1, 2
River Bend 1
Susquehanna 1, 2
Totals and Averages
Average per Reactor-Year

Reactor
Years
6
3
6
93
-

Three-year Collective
TEDE per Reactor
Year 2018–2020
(person-rem)
91.492
120.973
70.125
105.881

Number of
Workers with
Measurable
TEDE
5,354
2,386
4,139
85,298
917

Average TEDE
per Worker
(rem)
0.103
0.152
0.102
0.115
-

rem = roentgen equivalent man; TEDE = total effective dose equivalent.
(a) Sites where not all reactors had completed 3 full years of commercial operation as of December 31, 2020, are
not included in the table. Pilgrim 1 shutdown in June 2019 and Duane Arnold shutdown in October 2020.
Source: NRC 2020i, NRC 2022f.
No entry has been denoted by “-”.
Note: To convert rem to Sv, multiply by 0.01.

Table 3.9-8

Collective and Individual Worker Doses at Pressurized Water Reactors from
2018 through 2020

Nuclear Power Plant(a)
Arkansas 1, 2
Beaver Valley 1, 2
Braidwood 1, 2
Byron 1, 2
Callaway 1
Calvert Cliffs 1, 2
Catawba 1, 2
Comanche Peak 1, 2
D.C. Cook 1, 2
Davis-Besse 1
Diablo Canyon 1, 2
Farley 1, 2
Ginna
Harris 1
Indian Point 2, 3
McGuire 1, 2
Millstone 2, 3
North Anna 1, 2
Oconee 1, 2, 3
Palisades
Palo Verde 1, 2, 3
Point Beach 1, 2
Prairie Island 1, 2
Robinson 2
Salem 1, 2

NUREG-1437, Revision 2

Reactor
Years

Three-year Collective
TEDE per Reactor
Year 2018–2020
(person-rem)

Number of
Workers with
Measurable
TEDE

Average TEDE
per Worker
(rem)

6
6
6
6
3
6
6
6
6
3
6
6
3
3
6
6
6
6
9
3
9
6
6
3
6

46.195
23.138
18.330
19.356
20.308
28.376
32.390
24.247
25.465
34.879
18.901
24.385
25.411
23.139
27.580
27.430
32.707
33.117
16.660
151.607
13.056
32.618
13.724
37.262
52.018

4,580
2,016
2,084
2,280
908
2,428
2,839
1,996
2,412
1,615
2,055
2,116
1,039
1,252
4,037
2,800
2,520
2,300
3,011
2,019
2,970
1,683
1,346
1,750
3,028

0.061
0.069
0.053
0.051
0.067
0.070
0.068
0.073
0.063
0.065
0.055
0.069
0.073
0.055
0.041
0.059
0.078
0.086
0.050
0.225
0.040
0.116
0.061
0.064
0.103

3-94

Affected Environment

Nuclear Power Plant(a)
Seabrook
Sequoyah 1, 2
South Texas 1, 2
St. Lucie 1, 2
Summer 1
Surry 1, 2
Turkey Point 3, 4
Vogtle 1, 2
Waterford 3
Watts Bar 1, 2
Wolf Creek 1
Totals and Averages
Average per Reactor-Year

Reactor
Years
3
6
6
6
3
6
6
6
3
6
3
192
-

Three-year Collective
TEDE per Reactor
Year 2018–2020
(person-rem)
20.989
42.299
29.233
37.677
28.268
35.014
36.395
30.695
36.000
26.460
39.996
30.352

Number of
Workers with
Measurable
TEDE
1,052
3,060
1,972
2,668
1,362
2,516
2,629
2,216
1,734
2,797
2,110
81,200
423

Average TEDE
per Worker
(rem)
0.06
0.083
0.089
0.085
0.062
0.083
0.083
0.083
0.062
0.057
0.057
0.072
-

rem = roentgen equivalent man; TEDE = total effective dose equivalent.
(a) Sites where not all reactors had completed 3 full years of commercial operation as of December 31, 2020, are
not included in the table. Three Mile Island 1 shutdown in September 2019. Indian Point Unit 2 shutdown in
April 2020, and Indian Point 3 shutdown in April 2021, but dose was submitted for both Units 2 and 3 combined.
No entry has been denoted by “-”.
Source: NRC 2020i, NRC 2022f.

To identify trends, Figure 3.9-1 and Figure 3.9-2 provide the average and median values of the
annual collective dose per reactor for BWRs and PWRs for the years 1994 through 2020. The
reported ranges of the values are shown by the vertical lines that extend to the minimum and
maximum observed values. The rectangles indicate the range of values of the collective dose
exhibited by those plants ranked in the 25th through the 75th percentiles. The median values do
not normally fluctuate as much as the average values from year to year because they are not
affected as much by the extreme values of the collective doses. The median collective dose was
24 person-rem for PWRs and 80 person-rem for BWRs in 2020. These figures also show that, in
2020, 50 percent of the PWRs reported collective doses between 19 and 37 person-rem, while
50 percent of the BWRs reported collective doses between 58 and 93 person-rem (NRC 2020i,
NRC 2022f).
Table 3.9-9 and Table 3.9-10 present the average, maximum, and minimum collective and
individual occupational doses for all commercial nuclear power plants operating between 2006
and 2020.
For PWRs, the maximum variation in collective dose and annual average occupational dose
was observed for Palisades. From 2006 to 2020, the collective dose varied from 6 to
486 person-rem, and the annual average occupational dose varied from 0.04 to 0.39 rem.
The collective dose values were calculated per reactor rather than per site.
For BWRs, the maximum variation in collective dose and annual average occupational dose
was observed for Perry. From 2006 to 2020, the collective dose varied from 30 to
615 person-rem and the annual average occupational dose varied from 0.10 to 0.34 rem.
The collective dose values were calculated per reactor rather than per site.

3-95

NUREG-1437, Revision 2

Affected Environment

Figure 3.9-1 Average, Median, and Extreme Values of the Collective Dose per Boiling
Water Reactor from 1994 through 2020. Source: NRC 2022f.

NUREG-1437, Revision 2

3-96

Affected Environment

Figure 3.9-2 Average, Median, and Extreme Values of the Collective Dose per
Pressurized Water Reactor from 1994 through 2020. Source: NRC 2022f.

3-97

NUREG-1437, Revision 2

Affected Environment
Table 3.9-9

Annual Collective Dose and Annual Occupational Dose for Pressurized
Water Reactor Nuclear Power Plants from 2006 through 2020

Average
Maximum
Minimum
Collective
Collective
Collective
Annual
Annual
Annual
Dose
Dose
Dose
Average
Maximum
Minimum
(person-rem/ (person-rem/
(personOccupational Occupational Occupational
PWR Plant
reactor)(a)
reactor)(a)
rem/reactor)(a) Dose (rem)
Dose (rem)
Dose (rem)
Arkansas 1, 2
51
98
22
0.07
0.12
0.05
Beaver Valley 1, 2
48
185
13
0.09
0.17
0.06
Braidwood 1, 2
40
100
10
0.07
0.12
0.04
Byron 1, 2
43
122
13
0.07
0.13
0.04
Callaway 1
33
80
3
0.06
0.10
0.03
Calvert Cliffs 1, 2
45
102
23
0.11
0.17
0.06
Catawba 1, 2
46
106
16
0.08
0.12
0.05
Comanche Peak 1, 2
44
110
18
0.09
0.16
0.05
D.C. Cook 1, 2
45
156
15
0.08
0.18
0.05
Crystal River 3(b)
33
222
0
0.06
0.16
0.01
Davis-Besse 1
89
464
1
0.08
0.28
0.02
Diablo Canyon 1, 2
44
169
14
0.07
0.13
0.04
Farley 1, 2
29
70
15
0.07
0.11
0.05
Fort Calhoun(b)
55
289
3
0.09
0.18
0.03
Ginna
37
102
2
0.07
0.11
0.02
Harris 1
40
87
0
0.05
0.10
0.02
Indian Point 2, 3(b)
42
99
13
0.07
0.17
0.03
Kewaunee(b)
25
93
0
0.07
0.16
0.00
McGuire 1, 2
48
83
20
0.07
0.11
0.05
Millstone 2, 3
59
136
24
0.11
0.19
0.07
North Anna 1, 2
50
155
22
0.11
0.20
0.07
Oconee 1, 2, 3
42
84
10
0.07
0.13
0.04
Palisades(b)
175
486
6
0.19
0.39
0.04
Palo Verde 1, 2, 3
28
53
12
0.06
0.10
0.04
Point Beach 1, 2
41
80
20
0.12
0.17
0.08
Prairie Island 1, 2
33
69
3
0.08
0.13
0.05
Robinson 2
44
86
2
0.06
0.09
0.03
Salem 1, 2
54
164
17
0.08
0.12
0.04
San Onofre(b)
89
158
46
0.13
0.19
0.09
Seabrook
40
96
1
0.05
0.08
0.01
Sequoyah 1, 2
58
145
22
0.09
0.14
0.06
South Texas 1, 2
41
94
16
0.10
0.16
0.07
St. Lucie 1, 2
74
205
27
0.11
0.17
0.07
Summer 1
40
111
2
0.06
0.12
0.02
Surry 1, 2
60
117
20
0.11
0.19
0.06
Three Mile Island 1(b)
65
242
2
0.07
0.12
0.03
Turkey Point 3, 4
53
121
26
0.09
0.12
0.07
Vogtle 1, 2
45
78
23
0.10
0.13
0.07
Waterford 3
80
260
1
0.07
0.17
0.01
Watts Bar 1, 2
31
161
1
0.06
0.16
0.02
Wolf Creek 1
57
134
2
0.06
0.12
0.01
PWR = pressurized water reactor; rem = roentgen equivalent man.
(a) The collective dose per reactor was calculated by dividing the “Collective Dose per Site” by the number of
reactors on the site. Reported table values have been rounded.
(b) Indicates nuclear power plants that have been shutdown. Refer to Table 3.1-1 footnotes for shutdown year.
Note: To convert rem to Sv, multiply by 0.01.
Source: NRC 2020i, NRC 2022f.

NUREG-1437, Revision 2

3-98

Table 3.9-10 Annual Collective Dose and Annual Occupational Dose for Boiling Water Reactor Nuclear Power Plants from
2006 through 2020

3-99

Maximum
Collective Dose
(person-rem/
reactor)(a)
214
204
296
336
360
96
201
329
234
276
130
191
285
117
237
204
212
242
615
264
280
312
133
214

Minimum
Collective Dose
(person-rem/
reactor)(a)
96
80
13
18
14
39
16
0
21
21
42
17
91
58
22
71
18
84
30
18
71
16
66
13

Annual Average
Occupational
Dose (rem)
0.15
0.12
0.11
0.10
0.13
0.09
0.11
0.09
0.11
0.08
0.11
0.07
0.14
0.10
0.12
0.17
0.11
0.13
0.19
0.13
0.11
0.12
0.11
0.15

Annual Maximum
Occupational
Dose (rem)
0.20
0.14
0.18
0.16
0.21
0.14
0.18
0.13
0.16
0.13
0.18
0.12
0.20
0.15
0.18
0.23
0.18
0.20
0.34
0.35
0.24
0.18
0.14
0.25

Annual Minimum
Occupational
Dose (rem)
0.12
0.07
0.07
0.04
0.05
0.06
0.05
0.00
0.06
0.04
0.05
0.03
0.09
0.07
0.07
0.10
0.07
0.10
0.10
0.05
0.08
0.05
0.08
0.10

BWR = boiling water reactor.
(a) The collective dose per reactor was calculated by dividing the “Collective Dose per Site” by the number of reactors on the site. Reported table values have
been rounded.
(b) Indicates nuclear power plants that have been shutdown. Refer to Table 3.1-1 footnotes for shutdown year.
Note: To convert rem to Sv, multiply by 0.01.
Source: NRC 2020i, NRC 2022f.

Affected Environment

NUREG-1437, Revision 2

BWR Plant
Browns Ferry 1, 2, 3
Brunswick 1, 2
Clinton
Columbia
Cooper Station
Dresden 1, 2, 3
Duane Arnold(b)
Fermi 2
FitzPatrick
Grand Gulf
Hatch 1, 2
Hope Creek 1
LaSalle 1, 2
Limerick 1, 2
Monticello
Nine Mile Point 1, 2
Oyster Creek
Peach Bottom 2, 3
Perry
Pilgrim 1(b)
Quad Cities 1, 2
River Bend 1
Susquehanna 1, 2
Vermont Yankee(b)

Average
Collective Dose
(person-rem/
reactor)(a)
141
141
115
144
157
60
76
137
115
122
83
116
165
81
97
132
89
143
226
108
117
147
97
90

Affected Environment
Table 3.9-11 and Table 3.9-12 show the annual collective occupational dose for all commercial
nuclear power plants operating between 2006 to 2020 and Table 3.9-13 and Table 3.9-14 show
the annual individual average occupational dose for PWR and BWR commercial nuclear power
plants operating between 2006 to 2020. The year 2006 was chosen as a starting date because
the dose data for years prior to 2006 were presented in the 2013 LR GEIS and the 1996
LR GEIS. From 2006 to 2020, operating nuclear power plants would have gone through many
refueling outages, 5-year ISI, 10-year ISI, and also some refurbishment activities. To check for
trends, data were divided into two time frames: from 2006 to 2012 and from 2013 to 2020. The
averages for these two time frames were calculated and compared. The yearly average
collective dose from 2013 to 2020 was lower than the dose from 2006 to 2012. For a few
nuclear power plants, the average annual collective dose from 2013 to 2020 was higher, but in
all cases, the yearly average occupational dose was less than 0.39 rem. The yearly average
occupational dose was lower from 2013 to 2020 than from 2006 to 2012.
The data in Table 3.9-11, Table 3.9-12, Table 3.9-13, and Table 3.9-14 show that although
there are variations from year to year, there is no consistent trend. The average, maximum, and
minimum collective occupational doses are presented in Table 3.9-15 and Table 3.9-16 for
plants operated between 2014 to 2020. The average collective doses, however, are based on
widely varying yearly doses. For example, between 2014 to 2020, annual collective doses for
operating PWRs ranged from 0 to 486 person-rem; for operating BWRs, they ranged from 13 to
561 person-rem.
Average, maximum average, and minimum average individual occupational doses per reactor
type are presented in Table 3.9-17 and Table 3.9-18 for plants that operated between 2006 and
2020. From 2006 through 2020, the whole-body average dose for operating PWRs ranged from
0.0 to 0.42 rem; for operating BWRs, it ranged from 0.00 to 0.43 rem.
Table 3.9-19 provides the distribution of individual whole-body doses for 2020. The dose
distribution indicates that no worker received doses greater than 3 rem in 2020. Only one
worker received a whole-body dose exceeding 2 rem during 2020. At BWRs, less than
0.002 percent of the workers received doses greater than 2 rem. At PWRs, no worker received
a dose greater than 2 rem, and about 0.06 percent of the workers received a dose greater than
1 rem. Figure 3.9-3 shows the collective dose distribution by dose range for all commercial U.S.
reactors from 2016 to 2020. The distribution of collective dose has been fairly constant over the
past 5 years.
As mentioned in Section 3.9.1.1, under 10 CFR 20.2206, the NRC requires licensees to submit
an annual report of the results of individual monitoring. In addition to reporting data on external
exposures, licensees are required to report information about internal exposures. Licensees are
required to list for each intake, the radionuclide, pulmonary clearance class, intake mode, and
amount of the intake in microcuries. Eighteen intakes by ingestion were reported by licensees
during 2020 (10 for cobalt-60 and 8 for manganese-54). Two intakes were reported for the
inhalation mode in 2020 (1 for cobalt-60 and 1 for cobalt-58) (NRC 2020i, NRC 2022f).
Table 3.9-20 lists the number of individuals with measurable CEDE, collective CEDE, and
average measurable CEDE per individual as reported by different nuclear power reactor
stations.

NUREG-1437, Revision 2

3-100

Table 3.9-11 Annual Collective Dose for Pressurized Water Reactor Nuclear Power Plants from 2006 through 2020
(person-rem/reactor)(a)
No. of
Reactors

3-101

2006

2007

2008

2009

2010

2011

2012

2013

2014

2
2

Arkansas 1, 2
Beaver Valley 1, 2

72
185

53
43

98
42

51
112

50
25

58
36

22
63

25
21

36
31

68
48

2
2
1
2

Braidwood 1, 2
Byron 1, 2
Callaway 1
Calvert Cliffs 1, 2

100
67
6
102

49
64
73
77

52
70
46
37

71
42
5
48

32
28
59
64

35
122
80
48

84
25
5
58

16
29
43
31

21
40
37
31

2
2
2
1
1
2
2
1
1

Catawba 1, 2
Comanche Peak 1, 2
D.C. Cook 1, 2
Crystal River 3(b)
Davis-Besse 1
Diablo Canyon 1, 2
Farley 1, 2
Fort Calhoun(b)
Ginna

106
30
156
4
204
41
33
289
45

72
110
119
185
7
56
70
4
4

43
84
38
16
107
118
20
96
102

85
26
20
222
4
169
21
111
42

49
35
42
32
464
63
61
10

3

26
77
29
8
73
16
19
79
101

47
33
25
2
43
22
15
39
55

41
23
52
1
3
14
27
64
3

1
2
1
2
2
2
3
1
3
2

Harris 1
Indian Point 2, 3(b)
Kewaunee(b)
McGuire 1, 2
Millstone 2, 3
North Anna 1, 2
Oconee 1, 2, 3
Palisades(b)
Palo Verde 1, 2, 3
Point Beach 1, 2

87
145
75
54
87
41
74
240
51
20

65
55
11
78
82
155
84
257
50
26

10
71
93
83
136
31
62
23
53
72

41
40
56
40
80
39
60
267
33
47

83
100
5
41
41
91
64
220
38
48

5
32
79
60
85
45
61
22
20
80

80
55
39
31
37
53
44
245
20
35

2
1

Prairie Island 1, 2
Robinson 2

69
3

3
81

63
68

27
7

27
86

29
4

60
65

2015 2016

2017

2018

2019

2020

56
22

43
27

68
37

42
13

28
19

26
21
3
23

20
27
47
43

39
44
24
25

31
13
3
28

10
18
38
30

15
27
20
27

25
70
27
1
200
34
19
5
58

49
21
15
1
1
29
28
76
24

39
18
47
15
118
19
30
11
2

16
60
29
4
2
24
16
3
46

44
21
20
1
51
16
18
7
28

34
29
41
0
11
26
32
11
2

19
23
15
2
42
15
23
16
46

55
37
5
55
32
61
35
16
31
32

1
71
2
69
80
36
36
486
20
64

58
30
0
25
32
22
23
231
19
24

44
36
0
34
32
60
18
6
22
29

0
51
6
74
56
22
12
154
18
44

32
44
1
20
33
28
19
206
14
22

37
26
0
27
24
48
10
10
14
37

0
13
0
35
41
23
21
238
12
39

65
81

35
29

31
56

24
4

17
59

19
62

12
2

10
48

Affected Environment

NUREG-1437, Revision 2

Nuclear Power
Plant

2006
45

2007
59

2008
164

2009
51

2010
39

2011
63

2012
24

2013
30

2014
55

2015 2016
17
47

2017
68

2018
25

2019
50

2020
81

3-102

2
1
2
2
2

San Onofre(b)
Seabrook
Sequoyah 1, 2
South Texas 1, 2
St. Lucie 1, 2

158
77
121
75
60

46
4
62
46
205

63
75
42
94
56

89
87
83
40
66

100
4
28
40
99

15
66
55
70
148

111
54
145
25
93

3
2
22
30
37

1
40
39
17
61

1
96
68
42
94

1
2
53
16
38

0
29
24
28
36

12
33
61
35
56

6
1
38
28
27

16
28
28
24
30

1

Summer 1

61

3

49

56

2

32

82

5

111

65

3

50

49

5

31

2
1
2
2
1
2
1

Surry 1, 2
Three Mile Island 1(b)
Turkey Point 3, 4
Vogtle 1, 2
Waterford 3
Watts Bar 1, 2
Wolf Creek 1

117
5
75
58
110
161

104
114
54
60
20
2
4

75
2
49
69
134
35
95

97
242
83
40
255
32
74

56
39
43
45
5
3
11

57
130
31
59
100
26
134

84
13
121
30
260
31
8

34
126
41
39
3
1
111

29
13
57
78
69
14
28

91
171
40
30
66
32
75

22
17
38
29
3
2
91

29
83
54
40
61
38
3

59
3
26
23
1
18
73

26
7
42
25
70
23
45

20
4
41
43
37
38
2

97

(a) The collective dose per reactor was calculated by dividing the “Collective Dose per Site” by the number of reactors on the site, except for San Onofre, where
the NRC divided the reported “Collective Dose per Site” by 2 for the period 2006–2020. Reported table values have been rounded.
(b) Indicates nuclear power plants that have been shutdown. Refer to Table 3.1-1 footnotes for shutdown year.
Note: To convert rem to Sv, multiply by 0.01.
Source: NRC 2020i, NRC 2022f.

Affected Environment

NUREG-1437, Revision 2

No. of
Nuclear Power
Reactors
Plant
2
Salem 1, 2

Table 3.9-12 Annual Collective Dose for Boiling Water Reactor Nuclear Power Plants from 2006 through 2020
(person-rem/reactor)(a)
No. of
Reactors

3-103

2007

2008

2009

2010

2011

2012

2013

2014

2015

2016

2017

2018

2019

2020

185
145
31
306
50
92
184
194
59
178
69
191
114
99
191
165
47
192
505
241
125
131
132
171

161
177
205
55
360
66
24
35
185
168
95
35
109
88
44
151
212
106
52
23
137
312
96
214

116
175
48
305
254
77
140
149
35
31
93
169
148
117
174
119
37
155
615
264
159
219
133
61

186
204
220
55
61
71
201
146
220
188
123
161
192
84
56
188
206
110
32
26
121
40
88
206

99
191
228
336
349
79
30
24
35
21
88
25
170
92
237
122
47
195
308
241
144
211
84
176

155
185
14
45
279
47
135
145
170
276
96
154
112
80
39
204
165
153
43
22
97
34
88
45

128
181
129
224
36
46
16
26
39
35
70
151
192
67
199
109
30
242
374
176
96
188
117
170

130
131
18
34
203
39
122
200
136
182
95
37
183
69
35
132
145
215
85
37
78
16
107
21

96
115
98
289
28
46
20
235
21
25
42
170
251
62
130
80
23
198
387
219
85
128
103
50

135
84
33
27
196
47
111
55
28
195
111
140
169
63
29
128
134
101
36
44
71
71
119
13

117
108
155
180
30
43
17
265
162
40
51
32
285
92
116
71
18
99
328
163
87
273
83
14

166
92
78
43
133
40
78
329
232
167
70
150
175
61
29
193
38
89
30
39
81
70
74
18

121
111
159
191
14
68
16
65
24
35
47
169
155
79
128
76
22
84
301
18
102
256
71
45

108
80
13
18
93
41
16
561
149
228
65
17
91
58
22
129
23
85
31
62
91
37
66
53

(a) The collective dose per reactor was calculated by dividing the “Collective Dose per Site” by the number of reactors on the site. Reported table values have
been rounded.
(b) Indicates nuclear power plants that have been shutdown. Refer to Table 3.1-1 footnotes for shutdown year.
(c) NRC 2019f, data missing from Vol. 42 (NRC 2022f).
Note: To convert rem to Sv, multiply by 0.01.
Sources: NRC 2020i, NRC 2022f.

Affected Environment

NUREG-1437, Revision 2

3
2
1
1
1
3
1
1
1
1
2
1
2
2
1
2
1
2
1
1
2
1
2
1

Nuclear Power
Plant
2006
Browns Ferry 1, 2, 3 214
Brunswick 1, 2
140
Clinton
296
Columbia
56
Cooper Station
270
Dresden 1, 2, 3
96
Duane Arnold(b)
29
Fermi 2
181
FitzPatrick
234
Grand Gulf
60
Hatch 1, 2
130
Hope Creek 1
134
LaSalle 1, 2
124
Limerick 1, 2
97
Monticello
33
Nine Mile Point 1, 2
115
Oyster Creek
190
Peach Bottom 2, 3
124
Perry
65
Pilgrim 1(b)
44
Quad Cities 1, 2
280
River Bend 1
214
Susquehanna 1, 2
92
(b,c)
Vermont Yankee
50

3-104

PWR Plants
Arkansas 1, 2
Beaver Valley 1, 2
Braidwood 1, 2
Byron 1, 2
Callaway 1
Calvert Cliffs 1, 2
Catawba 1, 2
Comanche Peak 1, 2
D.C. Cook 1, 2
Crystal River 3(a)
Davis-Besse 1
Diablo Canyon 1, 2
Farley 1, 2
Fort Calhoun(b)
Ginna
Haddam Neck(c)
Harris 1
Indian Point 1(d)
Indian Point 2, 3(e)
Kewaunee(f)
Maine Yankee(g)
McGuire 1, 2
Millstone 2, 3
North Anna 1, 2
Oconee 1, 2, 3
Palisades(h)
Palo Verde 1, 2, 3
Point Beach 1, 2
Prairie Island 1, 2
Rancho Seco(i)
Robinson 2
Salem 1, 2

2006
0.12
0.17
0.12
0.12
0.03
0.17
0.12
0.09
0.18
0.03
0.15
0.08
0.09
0.18
0.09
0.10
0.10
0.04
0.18
0.14
0.09
0.15
0.11
0.12
0.27
0.10
0.09
0.12
0.22
0.04
0.06

2007
0.08
0.09
0.08
0.10
0.07
0.13
0.10
0.14
0.18
0.16
0.04
0.09
0.11
0.04
0.04
0.07
0.01
0.06
0.08
0.11
0.14
0.20
0.13
0.24
0.06
0.10
0.05
0.10
0.09
0.09

2008
0.11
0.08
0.08
0.09
0.06
0.10
0.08
0.16
0.08
0.06
0.11
0.11
0.06
0.11
0.10
0.01
0.05
0.02
0.10
0.16
0.01
0.10
0.19
0.08
0.10
0.09
0.09
0.15
0.12
0.03
0.09
0.10

2009
0.09
0.15
0.10
0.08
0.03
0.11
0.12
0.05
0.06
0.13
0.03
0.13
0.06
0.13
0.07
0.01
0.06
0.00
0.04
0.09
0.05
0.07
0.16
0.10
0.10
0.27
0.06
0.12
0.10
0.05
0.08

2010
0.07
0.07
0.07
0.06
0.07
0.15
0.09
0.07
0.07
0.05
0.28
0.09
0.09
0.06
0.04
0.01
0.08
0.01
0.10
0.03
0.08
0.07
0.11
0.18
0.10
0.24
0.07
0.11
0.08
0.09
0.08

2011
0.08
0.09
0.07
0.13
0.10
0.14
0.05
0.10
0.07
0.03
0.06
0.04
0.05
0.08
0.11
0.06
0.03
0.00
0.05
0.10
0.03
0.07
0.16
0.11
0.09
0.06
0.05
0.16
0.09
0.03
0.06

2012
0.05
0.10
0.09
0.06
0.03
0.16
0.08
0.07
0.07
0.02
0.07
0.05
0.05
0.08
0.08
0.01
0.07
0.00
0.09
0.07
0.04
0.05
0.10
0.14
0.07
0.22
0.05
0.12
0.13
0.06
0.07

2013
0.05
0.06
0.05
0.06
0.06
0.11
0.08
0.06
0.09
0.02
0.03
0.04
0.07
0.09
0.03
0.02
0.06
0.09
0.06
0.04
0.05
0.08
0.09
0.13
0.07
0.05
0.08
0.12
0.09
0.07
0.07

2014
0.05
0.07
0.05
0.07
0.06
0.11
0.05
0.12
0.07
0.03
0.10
0.07
0.05
0.03
0.09
0.02
0.02
0.11
0.03
0.03
0.08
0.13
0.10
0.05
0.39
0.06
0.17
0.09
0.06
0.04

2015
0.07
0.09
0.05
0.05
0.03
0.08
0.08
0.07
0.05
0.04
0.03
0.07
0.06
0.10
0.06
0.02
0.07
0.05
0.02
0.02
0.05
0.08
0.07
0.05
0.25
0.05
0.11
0.08
0.06
0.06

2016
0.07
0.06
0.05
0.06
0.07
0.10
0.08
0.06
0.08
0.16
0.12
0.05
0.06
0.07
0.02
0.02
0.06
0.08
0.02
0.02
0.06
0.07
0.11
0.05
0.04
0.06
0.11
0.07
0.03
0.08

2017
0.05
0.07
0.07
0.07
0.05
0.07
0.05
0.12
0.07
0.06
0.02
0.06
0.05
0.04
0.08
0.02
0.02
0.05
0.10
0.02
0.09
0.10
0.07
0.04
0.19
0.05
0.12
0.06
0.07
0.08

2018
0.07
0.08
0.07
0.04
0.04
0.06
0.07
0.08
0.05
0.05
0.07
0.04
0.06
0.09
0.06
0.02
0.05
0.05
0.13
0.01
0.05
0.09
0.07
0.05
0.22
0.04
0.08
0.07
0.06
0.09

2019
0.06
0.06
0.04
0.05
0.09
0.07
0.08
0.07
0.08
0.01
0.07
0.07
0.07
0.10
0.04
0.00
0.06
0.03
0.01
0.01
0.06
0.07
0.11
0.04
0.06
0.04
0.14
0.06
0.03
0.12

2020
0.05
0.07
0.05
0.06
0.05
0.08
0.05
0.07
0.06
0.05
0.06
0.06
0.07
0.10
0.09
0.04
0.02
0.03
0.00
0.02
0.07
0.08
0.07
0.05
0.27
0.04
0.12
0.05
0.06
0.10

Affected Environment

NUREG-1437, Revision 2

Table 3.9-13 Annual Average Measurable Occupational Doses at Pressurized Water Reactor Commercial Nuclear Power
Plant Sites from 2006 through 2020 (in rem)

3-105

PWR Plants
San Onofre 1(j)
San Onofre 2, 3(k)
San Onofre 1(j), 2, 3(k)
Seabrook
Sequoyah 1, 2
South Texas 1, 2
St. Lucie 1, 2
Summer 1
Surry 1, 2
Three Mile Island 1(l)
Turkey Point 3, 4
Vogtle 1, 2
Waterford 3
Watts Bar 1, 2
Wolf Creek 1
Yankee Rowe(m)
Zion 1, 2(n)

2006
0.12
0.19
0.06
0.14
0.14
0.10
0.09
0.19
0.04
0.11
0.13
0.09
0.16
0.12
0.02
0.02

2007
0.02
0.09
0.01
0.10
0.10
0.17
0.04
0.19
0.09
0.10
0.13
0.04
0.03
0.05
0.03

2008
0.02
0.12
0.06
0.09
0.16
0.10
0.08
0.14
0.03
0.09
0.12
0.11
0.08
0.10
0.02
0.02

2009
0.11
0.07
0.12
0.07
0.12
0.07
0.16
0.12
0.12
0.09
0.17
0.07
0.05
0.02
-

2010
0.12
0.01
0.07
0.09
0.15
0.02
0.12
0.05
0.08
0.10
0.02
0.05
0.02
0.03
0.03

2011
0.05
0.06
0.08
0.12
0.14
0.05
0.10
0.11
0.07
0.10
0.09
0.06
0.11
0.01
0.22

2012
0.10
0.05
0.11
0.08
0.11
0.11
0.14
0.05
0.12
0.08
0.14
0.06
0.03
0.01
0.41

2013
0.03
0.01
0.07
0.07
0.08
0.03
0.09
0.10
0.09
0.09
0.02
0.03
0.08
0.02
0.20

2014
0.02
0.04
0.09
0.08
0.11
0.12
0.08
0.06
0.09
0.11
0.07
0.05
0.04
0.01
0.22

2015
0.01
0.08
0.09
0.09
0.13
0.08
0.14
0.12
0.08
0.07
0.07
0.07
0.06
0.02
0.42

2016
0.02
0.03
0.09
0.08
0.08
0.02
0.07
0.05
0.09
0.08
0.01
0.02
0.07
0.01
0.24

2017
0.01
0.06
0.06
0.09
0.08
0.06
0.07
0.08
0.10
0.09
0.07
0.07
0.01
0.02
0.06

2018
0.19
0.07
0.09
0.10
0.10
0.07
0.10
0.03
0.08
0.07
0.01
0.05
0.06
0.01
0.01

2019
0.17
0.02
0.09
0.08
0.07
0.03
0.07
0.04
0.09
0.08
0.07
0.05
0.06
0.02
0.03

2020
0.15
0.06
0.07
0.08
0.10
0.07
0.06
0.04
0.08
0.09
0.05
0.06
0.01
0.01
0.00

Affected Environment

NUREG-1437, Revision 2

PWR = pressurized water reactor; rem = roentgen equivalent man.
(a) Crystal River ceased power generation in 2010 due to problems associated with containment building delamination. In June 2013, it was decided that it would
not be put in commercial operation again and, therefore, it is no longer included in the count of operating reactors.
(b) Fort Calhoun ceased power generation in October 2016 and is no longer included in the count of operating reactors.
(c) Haddam Neck (also known as Connecticut Yankee) ceased operations on December 4, 1996, and is no longer in the count of operating reactors.
(d) Indian Point 1 was shutdown October 31, 1974. All spent fuel was removed from the reactor vessel by January 1976. Therefore, it is no longer included in the
count of operating reactors.
(e) Indian Point 3 was purchased by a different utility in 1979 and subsequently reported its dose separately. Indian Point Units 1, 2, and 3 had been owned by
the same utility since 2001 and reported doses together. Indian Point Unit 2 shutdown in April 2020, and Indian Point Unit 3 shutdown in April 2021. NRC
approved the transfer of the licenses for both units for expedited decommissioning in November 2020.
(f) Kewaunee Power Station (Kewaunee) ceased operations in May 2013 and is no longer included in the count of operating reactors.
(g) Maine Yankee ceased operations in August 1997 and is no longer included in the count of operating reactors.
(h) Palisades shutdown in May 2022. Status to be determined.
(i) Rancho Seco ceased operations in June 1989 and is no longer in the count of operating reactors.
(j) San Onofre 1 ceased operations in November 1992 and is no longer in the count of operating reactors.
(k) San Onofre 2, 3 ceased power generation in January 2012, and in June 2013 it was decided that they would not be put back into commercial operation.
Therefore, they are no longer included in the count of operating reactors.
(l) Three Mile Island, Unit 1 (Three Mile Island) resumed commercial power generation in October 1985 after being under regulatory restraint since 1979.
Three Mile Island Unit 1 shutdown in September 2019.
(m) Yankee Rowe ceased operations as of October 1991 and will not be put in commercial operation again. It is no longer in the count of operating reactors.
(n) Zion 1, 2 ceased operations in 1997 and 1996, respectively, and are no longer included in the count of operating reactors.
No entry has been denoted by “-”.
Source: NRC 2020i, NRC 2022f.

3-106

BWR Plants
2006
Big Rock Point(a)
0.01
Browns Ferry 1 2,
0.18
3(b)
Brunswick 1, 2
0.13
Clinton
0.18
Columbia(c)
0.09
Cooper Station
0.21
Dresden 1(d), 2, 3
0.14
Duane Arnold
0.12
Fermi 2
0.13
FitzPatrick
0.15
Grand Gulf
0.06
Hatch 1, 2
0.18
Hope Creek 1
0.06
Humboldt Bay(e)
0.10
La Crosse(f)
Lasalle 1, 2
0.12
Limerick 1, 2
0.13
Millstone 1(g)
0.15
Monticello
0.12
Nine Mile Point 1, 2 0.20
Oyster Creek(h)
0.13
Peach Bottom 2, 3
0.16
Perry
0.13
Pilgrim 1
0.07
Quad Cities 1, 2
0.24
River Bend 1
0.14
Susquehanna 1, 2
0.10
Vermont Yankee(i)
0.13

2007
0.18

2008
0.18

2009
0.16

2010
0.2

2011
0.14

2012
0.15

2013
0.15

2014
0.16

2015
0.13

2016
0.13

2017
0.12

2018
0.15

2019
0.14

2020
0.12

0.13
0.10
0.14
0.07
0.12
0.17
0.13
0.11
0.10
0.10
0.09
0.07
0.43
0.12
0.13
0.03
0.18
0.18
0.10
0.20
0.31
0.17
0.13
0.12
0.11
0.14

0.14
0.15
0.08
0.21
0.09
0.09
0.08
0.13
0.09
0.14
0.03
0.04
0.04
0.09
0.13
0.12
0.22
0.14
0.12
0.10
0.06
0.13
0.17
0.10
0.15

0.13
0.11
0.16
0.16
0.12
0.15
0.10
0.07
0.06
0.14
0.08
0.02
0.03
0.15
0.15
0.14
0.16
0.10
0.15
0.34
0.20
0.13
0.11
0.14
0.16

0.13
0.14
0.07
0.08
0.10
0.18
0.09
0.15
0.10
0.14
0.08
0.06
0.04
0.16
0.11
0.11
0.22
0.12
0.13
0.12
0.08
0.11
0.05
0.09
0.19

0.14
0.14
0.15
0.20
0.10
0.07
0.06
0.07
0.04
0.11
0.06
0.04
0.05
0.12
0.09
0.12
0.18
0.11
0.14
0.19
0.20
0.12
0.11
0.09
0.17

0.11
0.07
0.04
0.16
0.07
0.12
0.10
0.11
0.11
0.12
0.07
0.10
0.08
0.11
0.08
0.07
0.23
0.12
0.12
0.11
0.08
0.09
0.05
0.08
0.16

0.09
0.11
0.13
0.07
0.08
0.06
0.04
0.07
0.09
0.10
0.07
0.14
0.07
0.20
0.08
0.16
0.15
0.10
0.17
0.23
0.15
0.09
0.10
0.13
0.11

0.07
0.10
0.04
0.16
0.07
0.12
0.11
0.08
0.11
0.12
0.04
0.10
0.09
0.17
0.09
0.13
0.18
0.13
0.14
0.19
0.09
0.08
0.05
0.11
0.12

0.09
0.08
0.14
0.07
0.07
0.05
0.13
0.08
0.04
0.05
0.06
0.08
0.07
0.20
0.08
0.15
0.10
0.08
0.13
0.24
0.16
0.09
0.14
0.12
0.10

0.10
0.07
0.05
0.15
0.08
0.10
0.07
0.08
0.13
0.13
0.08
0.11
0.13
0.08
0.09
0.15
0.10
0.10
0.10
0.07
0.08
0.13
0.11
0.11

0.12
0.12
0.10
0.08
0.07
0.08
0.13
0.14
0.07
0.09
0.08
0.11
0.20
0.10
0.14
0.10
0.07
0.11
0.23
0.10
0.09
0.18
0.11
0.10

0.12
0.07
0.09
0.13
0.06
0.11
0.13
0.16
0.13
0.11
0.09
0.03
0.12
0.07
0.11
0.20
0.11
0.10
0.14
0.06
0.10
0.12
0.11
-

0.13
0.12
0.14
0.05
0.09
0.08
0.05
0.06
0.04
0.08
0.12
0.00
0.13
0.08
0.12
0.11
0.18
0.09
0.25
0.05
0.11
0.18
0.11
0.25

0.11
0.07
0.07
0.1
0.06
0.09
0.00
0.13
0.09
0.09
0.10
0.00
0.09
0.08
0.09
0.17
0.13
0.11
0.35
0.10
0.10
0.09
0.24

BWR = boiling water reactor; rem = roentgen equivalent man.
(a) Big Rock Point ceased operations in August 1997 and is no longer included in the count of operating reactors.
(b) All three Browns Ferry units were placed on administrative hold in 1985. Units 2 and 3 were restarted in 1991 and 1995, respectively. Browns Ferry Unit 1 was
restarted during 2007.
(c) Energy Northwest changed the name of Washington Nuclear 2 to Columbia Generating Station (Columbia) in 2001.

Affected Environment

NUREG-1437, Revision 2

Table 3.9-14 Annual Average Measurable Occupational Doses at Boiling Water Reactor Commercial Nuclear Power Plant
Sites from 2006 through 2020 (in rem)

(d) Dresden 1 ceased power generation in 1978, and in 1985, it was decided that it would not be put in commercial operation again. Therefore, it is no longer
included in the count of operating reactors.
(e) Humboldt Bay had been shut down since 1976, and in 1983, PG&E announced its intention to decommission the unit. Therefore, it is no longer included in the
count of operating reactors.
(f) La Crosse ceased operations in 1987 and will not be put in commercial operation again. Therefore, it is no longer included in the count of operating reactors.
(g) Millstone 1 ceased operations in 1998 and is no longer included in the count of operating reactors. From 2008–2014, Millstone 1 voluntarily provided an
estimate of the collective dose for Unit 1, but not the number of individuals with measurable dose.
(h) Oyster Creek ceased operations in September 2018 and is no longer included in the count of operating reactors.
(i) Vermont Yankee ceased operations in December 2014 and is no longer in the count of operating reactors.
No entry has been denoted by “-”.
Source: NRC 2020i, NRC 2022f.

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Table 3.9-15 Average, Maximum, and Minimum Annual Collective Occupational Dose per
Plant for Pressurized Water Reactor Nuclear Power Plants in Person-rem
Year
2014
2015
2016
2017
2018
2019
2020

Average
51
44
31
37
34
26
34

Maximum
486
231
118
154
206
70
238

Minimum
1
1
2
1
1
1
0

rem = roentgen equivalent man.
Note: To convert rem to Sv, multiply by 0.01.
Source: NRC 2020i, NRC 2022f.

Table 3.9-16 Average, Maximum, and Minimum Annual Collective Occupational Dose per
Plant for Boiling Water Reactor Nuclear Power Plants in Person-rem
Year
2014
2015
2016
2017
2018
2019
2020

Average
109
122
98
118
111
110
100

Maximum
215
387
196
328
329
301
561

Minimum
16
20
27
17
29
14
13

rem = roentgen equivalent man.
Note: To convert rem to Sv, multiply by 0.01.
Source: NRC 2020i, NRC 2022f.

Table 3.9-17 Average, Maximum, and Minimum Annual Individual Occupational
Whole-Body Dose for Pressurized Water Reactor Nuclear Power Plants in rem
Year
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020

Average Whole-Body
Dose (rem) per Plant
0.11
0.09
0.09
0.09
0.08
0.08
0.09
0.07
0.08
0.08
0.07
0.07
0.07
0.06
0.06

Maximum Average Whole- Minimum Average WholeBody Dose (rem)
Body Dose (rem)
0.27
0.02
0.24
0.01
0.19
0.01
0.27
0.00
0.28
0.01
0.22
0.00
0.41
0.00
0.20
0.01
0.39
0.01
0.42
0.01
0.24
0.01
0.19
0.01
0.22
0.01
0.17
0
0.27
0

rem = roentgen equivalent man.
Note: To convert rem to Sv, multiply by 0.01. Values derived from Table 3.9-13.
Source: NRC 2020i, NRC 2022f.

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Table 3.9-18 Average, Maximum, and Minimum Annual Individual Occupational WholeBody Dose for Boiling Water Reactor Nuclear Power Plants in rem
Year
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020

Average Whole-Body
Dose (rem) per Plant
0.13
0.14
0.12
0.13
0.12
0.12
0.10
0.11
0.11
0.11
0.10
0.11
0.11
0.12
0.11

Maximum Average Whole- Minimum Average WholeBody Dose (rem)
Body Dose (rem)
0.24
0.01
0.43
0.03
0.22
0.03
0.34
0.06
0.22
0.05
0.20
0.04
0.23
0.04
0.23
0.04
0.19
0.04
0.24
0.04
0.15
0.03
0.23
0.07
0.20
0.03
0.25
0
0.35
0

Note: To convert rem to Sv, multiply by 0.01. Values derived from Table 3.9-14.
Source: NRC 2020i, NRC 2022f.

Table 3.9-19 Number of Workers at Boiling Water Reactors and Pressurized Water
Reactors Who Received Whole-Body Doses within Specified Ranges during
2020
Whole Body Dose Range (rem)(a)
No Measurement
<0.10
0.10–0.25
0.25–0.50
0.50–0.75
0.75–1.0
1.0–2.0
2.0–3.0
3.0–4.0
4.0–5.0
>5.0
Total Number Monitored
Number with Measured Dose
Total Collective Dose (Whole Body) (person-rem)

BWRs (31)
20,833
18,180
5,078
2,115
607
243
174
1
0
0
0
47,231
26,398
2,946.746

PWRs (64)
51,357
20,841
4,176
1,077
208
77
43
0
0
0
0
77,779
26,422
1,952.382

Total (95)
72,190
39,021
9,254
3,192
815
320
217
1
0
0
0
125,010
52,820
4,899.128

BWRs = boiling water reactors; PWRs = pressurized water reactors; rem = roentgen equivalent man.
(a) Dose values exactly equal to the values separating ranges are reported in the next higher range.
Note: To convert rem to Sv, multiply by 0.01.
Source: NRC 2020i, NRC 2022f.

A portion of the total workforce can be defined as “transient.” These individuals are usually
employed for special functions and may be employed at multiple reactor sites during a given
year. Data for individual reactors described earlier include transient workers but only for each
power plant. Thus, some workers are counted more than once, and some workers receive
greater annual doses than are reported by individual plants. In 2020, there were about 21,000 of

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these people (NRC 2020i, NRC 2022f). Over the years, doses to transient workers at nuclear
power plants have been decreasing in the same way as doses to more permanent workers,
going from an average of 0.32 rem in 2005 (NRC 2006f) to 0.20 rem in 2020 (NRC 2020i,
NRC 2022f). In 2020, no transient workers received whole-body doses more than 3 rem
(NRC 2022f).
Figure 3.9-3 shows the percentage of workers that received dose in five dose ranges for all
commercial U.S. reactors for 2016 through 2020 from NUREG-0713 (NRC 2020i, NRC 2022f).
The data shows that the majority of the doses were less than 0.1 rem with much fewer dose
contributions between 0.1 and 2 rem.

Figure 3.9-3 Dose Distribution for All Commercial U.S. Reactors by Dose Range (rem),
2016 through 2020. Source: NRC 2022f.
Table 3.9-20 Collective and Average Committed Effective Dose Equivalent for
Commercial U.S. Nuclear Power Plant Sites in 2020
Nuclear Power Plant
Beaver Valley
Fermi
McGuire
Waterford
Summer

Number of Individuals
with Measurable CEDE
1
9
1
25
5

Collective CEDE
(person-rem)
0.004
0.021
0.029
0.113
0.005

CEDE = committed effective dose equivalent; rem = roentgen equivalent man.
Note: To convert rem to Sv, multiply by 0.01.
Source: NRC 2020i, NRC 2022f.

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Average Measurable
CEDE (rem)
0.004
0.002
0.029
0.005
0.001

Affected Environment
As mentioned in Section 3.9.1.1, under 10 CFR 20.2202 and 10 CFR 20.2203, the NRC
requires that all licensees submit reports of all occurrences involving personnel radiation
exposures and releases of radioactive material that exceed certain control levels. For 2020,
there was no occurrence reported for nuclear power reactors (NRC 2020i, NRC 2022f).
3.9.1.3

Public Radiological Exposures

Commercial nuclear power plants, under controlled conditions, release small amounts of
radioactive materials to the environment during normal operation. Radioactive waste
management systems are incorporated into each plant. They are designed to remove most of
the fission product radioactivity that leaks from the fuel, as well as most of the activation- and
corrosion-product radioactivity produced by neutrons in the vicinity of the reactor core. The
amounts of radioactivity released through vents and discharge points to areas outside the plant
boundaries are recorded and published annually in the radioactive effluent release reports for
each facility. These reports are publicly available on the NRC’s Agencywide Documents Access
and Management System. The effluent releases result in radiation doses to humans. Nuclear
power plant licensees must comply with Federal regulations (e.g., 10 CFR Part 20, Appendix I
to 10 CFR Part 50, 10 CFR 50.36a, and 40 CFR Part 190) and technical specifications in the
operating license.
Potential environmental pathways through which persons may be exposed to radiation
originating in a nuclear power plant include the atmospheric and water pathways. Radioactive
materials released under controlled conditions include fission products and activation products.
Fission product releases consist primarily of the noble gases and some of the more volatile
materials like tritium, isotopes of iodine, and cesium. These materials are monitored before
release to determine whether the limits on releases can be met. Releases to the aquatic
pathways are similarly monitored. Radioactive materials in the liquid effluents are processed in
radioactive waste treatment systems. The major radionuclides released to aquatic systems have
been tritium, isotopes of cobalt, and cesium.
When an individual is exposed to radioactive materials released by the plant into air or water
pathways, the dose is determined in part by the amount of time spent in the vicinity of the
source or the amount of time the radionuclides inhaled or ingested are retained in the
individual’s body (exposure). The consequences associated with this exposure are evaluated by
calculating the dose. The major exposure pathways include the following:
• inhalation of contaminated air;
• drinking milk or eating meat from animals that graze on open pasture on which radioactive
contamination may be deposited;
• eating vegetables grown near the site; and
• drinking (untreated) water or eating fish caught near the point of discharge of liquid effluents.
Radiation doses are calculated for the maximally exposed individual (MEI) (that is, a
hypothetical individual potentially subject to maximum exposure). Doses are calculated by using
plant-specific data where available. For those cases in which plant-specific data are not readily
available, conservative (overestimating) assumptions are used to estimate dose.
Members of the general public are also exposed when radioactive waste is shipped offsite. The
public radiation exposures from radioactive material transportation have been addressed in
Table S-4 of 10 CFR Part 51. Table S-4 indicates that the cumulative dose to the exposed

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public from the transport of both LLW and spent fuel is estimated to be about 0.03 person-Sv
(3 person-rem) per reactor year (see analysis in Chapter 4, Section 4.14.1.4, and Table 4.14-2).
3.9.1.3.1 Effluent Pathways for Calculations of Dose to the Public
Radioactive effluents can be divided into several groups based on their physical characteristics.
Among the airborne effluents, the radioisotopes of the noble gases krypton, xenon, and argon
neither deposit on the ground nor are absorbed and accumulated within living organisms;
therefore, the noble gas effluents act primarily as a source of direct external radiation emanating
from the effluent plume. For these effluents, dose calculations are performed for the site
boundary where the highest external radiation doses to a member of the general public are
estimated to occur.
A second group of airborne radioactive effluents—the fission product radioiodines and tritium—
are also gaseous, but some of them can be deposited on the ground or inhaled during
respiration. For this class of effluents, estimates are made of direct external radiation doses
from ground deposits (as well as exposure to the plume). Estimates are also made of internal
radiation doses to the total body, thyroid, bone, and other organs from inhalation and from
vegetable, milk, and meat consumption.
A third group of airborne effluents consists of particulates and includes fission products, such as
cesium and strontium, and activated corrosion products, such as cobalt and chromium. These
effluents contribute to direct external radiation doses and to internal radiation doses through the
same pathways as those described above for the radioiodine. Doses from the particulates are
combined with those from the radioiodines and tritium for comparison with one of the design
objectives of Appendix I to 10 CFR Part 50.
Liquid effluent constituents could include fission products such as strontium and iodine;
activation and corrosion products, such as sodium, iron, and cobalt; and tritiated water. These
radionuclides contribute to the internal doses through the pathways described above from fish
consumption, water ingestion (as drinking water), and consumption of meat or vegetables raised
near a nuclear plant and using irrigation water, as well as from any direct external radiation from
recreational use of the water near the point of a plant’s discharge.
The release of each radioisotope and the site-specific meteorological and hydrological data
serve as input to radiation dose models that estimate the maximum radiation dose that would be
received outside the facility by way of a number of pathways for individual members of the
public and for the general public as a whole. These models and the radiation dose calculations
are discussed in Revision 1 of Regulatory Guide 1.109 (NRC 1977).
Doses from gaseous radioactive iodine and radioactive material in particulate form in gaseous
effluents are calculated for individuals at the location or source point (e.g., site boundary,
garden, residence, dairy animal, meat animal) where the highest radiation dose to a member of
the public has been established from each applicable pathway (e.g., ground deposition,
inhalation, vegetable consumption, milk consumption, meat consumption). Only those pathways
associated with airborne effluents that are known to exist at a single location are combined to
calculate the total maximum exposure to an exposed individual. Pathway doses associated with
liquid effluents are conservatively combined without regard to any single location but are
assumed to be associated with the maximum exposure of an individual.

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A number of possible exposure pathways to humans are evaluated to determine the impact of
routine releases from each nuclear facility on members of the general public living and working
outside the site boundaries. A listing of these exposure pathways include external radiation
exposure from gaseous effluents, inhalation of iodines and particulate contaminants in the air,
consuming milk from dairy animals or eating meat from an animal that grazes on open pasture
near the site on which iodines or particulates may be deposited, eating vegetables from a garden
near the site (that may be contaminated by similar deposits), and drinking water or eating fish or
invertebrates caught near the point of liquid effluent discharge. Other exposure pathways may
include external irradiation from surface deposition; eating of animals and crops grown near the
site and irrigated with water contaminated by liquid effluents; shoreline, boating, and swimming
activities; drinking potentially contaminated water; and direct radiation being emitted from the
plant itself. Calculations for most pathways are limited to a radius of 50 mi (80 km). For this
study, effluent and MEI dose information was collected from a series of publicly available annual
radioactive effluent release reports that licensees submit to the NRC every year.
3.9.1.3.2 Radiological Monitoring
Background radiation measurements at all reactor sites were obtained prior to operation of the
nuclear reactor. Thus, each facility has characterized the natural background levels of
radioactivity and radiation and their variations among the anticipated important exposure
pathways in the areas surrounding the facilities. The operational, Radiological Environmental
Monitoring Program (REMP) is conducted at each site to provide data on measurable levels of
radiation and radioactive materials in the site environs in accordance with 10 CFR Parts 20
and 50. The REMP quantifies the environmental impacts associated with radioactive effluent
releases from the plant. The REMP monitors the environment throughout the plant’s operating
lifetime to monitor radioactivity in the local environment. The REMP provides a mechanism for
determining the levels of radioactivity in the environment to ensure that any accumulation of
radionuclides released into the environment will not become significant as a result of plant
operations. The REMP also measures radioactivity from other nuclear facilities that may be in
the area (i.e., other nuclear power plants, hospitals using radioactive material, research
facilities, or any other facility licensed to use radioactive material). Thus, the REMP monitors the
cumulative impacts from all sources of radioactivity in the vicinity of the power plant. To obtain
information on radioactivity around the plant, samples of environmental media (e.g., surface
water; groundwater; drinking water; air; milk; locally grown crops; locally produced food
products; river, ocean, or lake sediment; and fish and other aquatic biota) are collected from
areas surrounding the plant for analysis to measure the amount of radioactivity, if any, in the
samples. The media samples reflect the radiation exposure pathways (i.e., inhalation, ingestion,
and physical location near the plant) to the public from radioactive effluents released by the
nuclear power plant and from background radiation (i.e., cosmic sources, naturally occurring
radioactive material, including radon, and global fallout). The NRC has standards for the amount
of radioactivity in the sample media, which if exceeded, must be reported to the NRC, and the
licensee must conduct an investigation. The REMP supplements the radioactive effluent
monitoring program by verifying that measurable concentrations of radioactive materials and
levels of radiation in the environment are not higher than expected when compared against data
on the amount of radioactive effluent discharged.
The REMP can also identify the existence of effluents from unmonitored release points. A
periodic land use survey identifies changes in the use of unrestricted areas to provide a basis
for modifying the monitoring programs to reflect a new exposure pathway or a different plantspecific dose calculation parameter. The results of the REMP are documented by each licensee
in the annual radiological environmental monitoring reports and submitted to NRC every year

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and are publicly available in NRC’s Agencywide Documents Access and Management System
document system. The radiological environmental monitoring reports can also be accessed by
navigating the reactor webpage for each site on the NRC website; effluent reports and
environmental reports are available through the “Plant Environmental Report” section of the key
documents.
3.9.1.3.3 Public Radiation Doses
Table 3.9-21 and Table 3.9-22 show the total body dose to the public, ground-level air dose,
and dose to a critical organ for 3 years (2019 through 2021) from gaseous effluent releases for
several PWRs and BWRs. The dose varies from year to year and also from reactor to reactor.
The maximum total body dose is 0.47 mrem, maximum dose to a critical organ is 0.63 mrem,
maximum ground-level air dose from gamma radiation is 0.99 mrad, and maximum ground-level
dose from beta radiation is 0.013 mrad. All doses are much less than the design objectives of
Appendix I of 10 CFR Part 50 provided in Table 3.9-2.
Table 3.9-23 and Table 3.9-24 show the total body dose to the public and dose to a critical
organ for 3 years (2019 through 2021) from liquid effluent releases for the same PWRs and
BWRs. The total body dose and dose to critical organ of the MEI from liquid effluent releases
varies from year to year and also from reactor to reactor.
The doses from both gaseous and liquid effluents are much less than the design objectives of
Appendix I of 10 CFR Part 50 provided in Table 3.9-2 and the EPA standards in 40 CFR 190,
Subpart B provided in Table 3.9-3. Calculated MEI doses are also reported in annual effluent
release reports based on the gaseous and liquid effluent releases for each plant. Under most
circumstances, the dose calculations to the MEI, which are made by the plants, overestimate
the calculated dose because of conservative assumptions. For most reactors, the annual MEI
doses are a few millirem or less.
Table 3.9-21 Doses from Gaseous Effluent Releases by Select Pressurized Water
Reactors from 2019 through 2021
Year
2019
2019
2019
2019
2019
2019
2019
2019
2019
2019
2020
2020
2020
2020
2020

No. of
PWR
Reactors
Comanche Peak
2
D.C. Cook
2
(b)
Palo Verde 1
1
(b)
Palo Verde 2
1
Palo Verde 3(b)
1
Robinson
1
Salem 1
1
Salem 2
1
Seabrook
1
Surry
2
Comanche Peak
2
D.C. Cook
2
(b)
Palo Verde 1
1
(b)
Palo Verde 2
1
Palo Verde 3(b)
1

NUREG-1437, Revision 2

Total Body
(mrem)(a)
8.00 × 10-2
1.33 × 10-3
1.60 × 10-4
1.60 × 10-4
1.60 × 10-4
4.74 × 10-1
2.13 × 10-2
2.52 × 10-2
7.93 × 10-2
NR
8.00 × 10-2
1.23 × 10-3
3.63 × 10-4
3.63 × 10-4
3.63 × 10-4

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Gamma
(mrad)(a)
3.12 × 10-4
2.78 × 10-3
5.02 × 10-4
3.99 × 10-4
1.46 × 10-3
3.12 × 10-3
1.01 × 10-4
1.33 × 10-4
4.87 × 10-5
7.14 × 10-6
4.51 × 10-4
2.26 × 10-3
6.23 × 10-4
9.90 × 10-1
8.50 × 10-4

Beta (mrad)(a)
1.14 × 10-4
2.06 × 10-3
2.86 × 10-4
1.41 × 10-4
5.89 × 10-4
1.18 × 10-3
4.70 × 10-5
4.83 × 10-5
3.17 × 10-5
9.04 × 10-6
1.65 × 10-4
8.92 × 10-4
2.49 × 10-4
3.64 × 10-4
3.1 × 10-4

Critical Organ
(mrem)(a)
4.35 × 10-4
1.28 × 10-1
1.69 × 10-1
1.40 × 10-1
3.12 × 10-1
5.79 × 10-1
9.35 × 10-2
1.17 × 10-1
3.44 × 10-1
9.40 × 10-2
6.30 × 10-4
1.02 × 10-1
3.11 × 10-3
1.95 × 10-1
2.32 × 10-1

Affected Environment

Year
2020
2020
2020
2020
2020
2021
2021
2021
2021
2021
2021
2021
2021
2021
2021

No. of
PWR
Reactors
Robinson
1
Salem 1
1
Salem 2
1
Seabrook
1
Surry
2
Comanche Peak
2
D.C. Cook
2
Palo Verde 1(b)
1
(b)
Palo Verde 2
1
Palo Verde 3(b)
1
Robinson
1
Salem 1
1
Salem 2
1
Seabrook
1
Surry
2

Total Body
(mrem)(a)
2.57 × 10-1
1.85 × 10-2
2.09 × 10-2
8.01 × 10-2
NR
9.00 × 10-2
3.24 × 10-3
7.10 × 10-4
7.10 × 10-4
7.10 × 10-4
2.58 × 10-1
3.28 × 10-2
2.81 × 10-2
1.08 × 10-1
NR

Gamma
(mrad)(a)
7.90 × 10-3
1.00 × 10-4
1.43 × 10-4
5.61 × 10-1
9.84 × 10-5
4.04 × 10-4
6.01 × 10-3
2.29 × 10-4
5.96 × 10-4
3.49 × 10-3
5.25 × 10-3
6.27 × 10-5
1.12 × 10-4
9.40 × 10-4
3.82 × 10-5

Beta (mrad)(a)
2.90 × 10-3
4.61 × 10-5
5.31 × 10-5
2.89 × 10-4
3.68 × 10-5
1.46 × 10-4
2.16 × 10-3
8.07 × 10-5
5.75 × 10-4
1.45 × 10-3
3.74 × 10-3
2.24 × 10-5
4.03 × 10-5
3.94 × 10-4
1.79 × 10-5

Critical Organ
(mrem)(a)
5.18 × 10-1
7.97 × 10-2
1.01 × 10-1
3.29 × 10-1
1.05 × 10-1
5.63 × 10-4
5.22 × 10-3
1.62 × 10-1
3.66 × 10-1
3.81 × 10-1
5.59 × 10-1
1.46 × 10-1
1.26 × 10-1
4.54 × 10-1
9.13 × 10-2

PWR = pressurized water reactor; mrem = millirem; mrad = millirad; NR = not reported.
(a) Compare the values presented in this table with the design objectives presented in Table 3.9-2, Appendix I to
10 CFR 50 and Table 3.9-3, 40 CFR Part 190, Subpart B.
(b) Palo Verde reports total body dose from the site, not per individual unit. The total site value provided by Palo
Verde was divided by 3 to represent individual estimated contribution.
Note: To convert mrem to mSv, multiply by 0.01.
Sources: Annual effluent release reports. The radiological environmental monitoring reports can also be accessed by
navigating the reactor webpage for each site on the NRC website; effluent reports and environmental reports are
available through the “Plant Environmental Report” section of the key documents.

Table 3.9-22 Doses from Gaseous Effluent Releases by Select Boiling Water Reactors
from 2019 through 2021
Year
2019
2019
2019
2019
2019
2019
2020
2020
2020
2020
2020
2020
2021
2021
2021
2021

BWR
Fermi 2
Hatch 1
Hatch 2
Hope Creek
Limerick
Columbia
Fermi 2
Hatch 1
Hatch 2
Hope Creek
Limerick
Columbia
Fermi 2
Hatch 1
Hatch 2
Hope Creek

No. of
Reactors
1
1
1
1
2
1
1
1
1
1
2
1
1
1
1
1

Total Body
(mrem)(a)
1.40 × 10-1
1.19 × 10-2
1.39 × 10-2
4.11 × 10-2
9.79 × 10-4
4.49 × 10-2
1.10 × 10-1
2.09 × 10-2
1.99 × 10-2
5.00 × 10-2
2.52 × 10-3
3.75 × 10-2
1.40 × 10-1
3.02 × 10-2
1.84 × 10-2
4.65 × 10-2

3-115

Gamma
(mrad)(a)
3.13 × 10-6
0
0
1.90 × 10-3
1.03 × 10-3
2.96 × 10-2
1.15 × 10-5
0
0
1.90 × 10-3
2.66 × 10-3
2.85 × 10-2
1.44 × 10-6
0
0
1.13 × 10-7

Beta
(mrad)(a)
1.23 × 10-6
0
0
3.21 × 10-3
6.12 × 10-4
1.04 × 10-2
4.51 × 10-6
0
0
3.20 × 10-3
2.13 × 10-3
1.00 × 10-2
5.53 × 10-7
0
0
5.36 × 10-8

Critical Organ
(mrem)(a)
1.50 × 10-1
1.19 × 10-2
1.40 × 10-2
4.03 × 10-2
1.62 × 10-3
2.10 × 10-1
4.14 × 10-1
2.09 × 10-2
2.02 × 10-2
2.37 × 10-1
4.39 × 10-3
1.67 × 10-1
6.27 × 10-1
3.03 × 10-2
1.89 × 10-2
2.03 × 10-1

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Year
BWR
2021 Limerick
2021 Columbia

No. of
Reactors
2
1

Total Body
(mrem)(a)
1.89 × 10-2
3.31 × 10-2

Gamma
(mrad)(a)
1.97 × 10-2
1.93 × 10-2

Beta
(mrad)(a)
1.26 × 10-2
6.82 × 10-3

Critical Organ
(mrem)(a)
3.26 × 10-2
3.45 × 10-2

BWR = boiling water reactor; mrem = millirem; mrad = millirad.
(a) Compare the values presented in this table with the design objectives presented in Table 3.9-2, Appendix I to
10 CFR 50 and Table 3.9-3, 40 CFR Part 190, Subpart B.
Note: To convert mrem to mSv, multiply by 0.01.
Sources: Annual effluent release reports. The radiological environmental monitoring reports can also be accessed by
navigating the reactor webpage for each site on the NRC website; effluent reports and environmental reports are
available through the “Plant Environmental Report” section of the key documents.

Table 3.9-23 Dose from Liquid Effluent Releases by Select Pressurized Water Reactor
Nuclear Power Plants for 2019 through 2021
Year
2019
2019
2019
2019
2019
2019
2019
2019
2020
2020
2020
2020
2020
2020
2020
2020
2021
2021
2021
2021
2021
2021
2021
2021

PWR Name
Comanche Peak
D.C. Cook
Palo Verde 1–3
Robinson
Salem 1
Salem 2
Seabrook
Surry
Comanche Peak
D.C. Cook
Palo Verde 1–3
Robinson
Salem 1
Salem 2
Seabrook
Surry
Comanche Peak
D.C. Cook
Palo Verde 1–3
Robinson
Salem 1
Salem 2
Seabrook
Surry

No. of
Reactors
2
2
3
1
1
1
1
2
2
2
3
1
1
1
1
2

2
2
3
1
1
1
1
2

Total Body (mrem)(a)
1.27 × 10-1
8.43 × 10-2
NR
1.75 × 10-6
1.35 × 10-2
3.99 × 10-3
1.86 × 10-4
3.44 × 10-4
1.14 × 10-1
8.87 × 10-2
NR
2.01 × 10-3
1.36 × 10-2
4.67 × 10-3
5.15 × 10-4
1.77 × 10-4
1.20 × 10-1
5.01 × 10-2
NR
1.45 × 10-3
2.15 × 10-2
3.57 × 10-3
7.30 × 10-4
3.91 × 10-4

Critical Organ (mrem)(a)
1.27 × 10-1
8.46 × 10-2
NR
1.83 × 10-5
1.67 × 10-2
2.60 × 10-2
2.33 × 10-4
4.08 × 10-4
1.14 × 10-1
4.80 × 10-2
NR
5.63 × 10-3
2.93 × 10-2
3.40 × 10-2
8.42 × 10-4
2.33 × 10-4
1.20 × 10-1
5.01 × 10-2
NR
1.57 × 10-3
2.19 × 10-2
5.32 × 10-3
1.65 × 10-3
4.66 × 10-4

PWR = pressurized water reactor; mrem = millirem; NR = not reported.
(a) Compare the values presented in this table with the design objectives from Table 3.9-2, Appendix I to
10 CFR 50.
Note: To convert mrem to mSv, multiply by 0.01.
Sources: Annual effluent release reports. The radiological environmental monitoring reports can also be accessed by
navigating the reactor webpage for each site on the NRC website; effluent reports and environmental reports are
available through the “Plant Environmental Report” section of the key documents.

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Table 3.9-24 Dose from Liquid Effluent Releases from Select Boiling Water Reactor
Nuclear Power Plants for 2019 through 2021
Year

2019
2019
2019
2019
2019
2019
2020
2020
2020
2020
2020
2020
2021
2021
2021
2021
2021
2021

BWR Name

Fermi 2
Hatch 1
Hatch 2
Hope Creek
Limerick
Columbia
Fermi 2
Hatch 1
Hatch 2
Hope Creek
Limerick
Columbia
Fermi 2
Hatch 1
Hatch 2
Hope Creek
Limerick
Columbia

No. of
Reactors

Total Body (mrem)(a)

Critical Organ (mrem)(a)

1
1
1
1
2
1
1
1
1
1
2
1
1
1
1
1
2
1

NR
9.85 × 10-4
3.88 × 10-4
7.92 × 10-4
9.63 × 10-3
NR
NR
5.83 × 10-4
6.99 × 10-4
1.65 × 10-2
2.83 × 10-4
NR
NR
2.60 × 10-3
2.77 × 10-3
3.40 × 10-4
7.83 × 10-2
NR

NR
8.01 × 10-4
1.01 × 10-3
2.41 × 10-3
1.23 × 10-2
NR
NR
7.56 × 10-4
7.66 × 10-4
5.13 × 10-2
2.34 × 10-3
NR
NR
3.15 × 10-3
3.98 × 10-3
1.65 × 10-3
7.84 × 10-2
NR

BWR = boiling water reactor; mrem = millirem; NR = not reported.
(a) Compare the values presented in this table with the design objectives from Table 3.9-2, Appendix I to
10 CFR 50.
Note: To convert mrem to mSv, multiply by 0.01.
Sources: Annual effluent release reports. The radiological environmental monitoring reports can also be accessed by
navigating the reactor webpage for each site on the NRC website; effluent reports and environmental reports are
available through the “Plant Environmental Report” section of the key documents.

3.9.1.3.4 Radiological Exposure from Naturally Occurring and Artificial Sources
Table 3.9-25 identifies background doses to a typical member of the U.S. population as
summarized in National Council on Radiation Protection and Measurements Report (NCRP)
160 (2009) and NCRP Report 180 (2019). In the table, the annual values are rounded to the
nearest 1 percent. A total average annual effective dose equivalent of 554 mrem/yr to members
of the U.S. population is contributed by two primary sources: naturally occurring background
radiation and medical exposure to patients.
Natural radiation sources other than radon result in 15 percent of the typical radiation dose
received. The larger source of radiation dose in ubiquitous background (41 percent) is from
radon, particularly because of homes and other buildings that trap radon and significantly
enhance its dose contribution over open-air living. The remaining 44 percent of the average
annual effective dose equivalent consists of radiation mostly from medical procedures
(computed tomography, 25 percent; nuclear medicine, 7 percent; interventional fluoroscopy,
5 percent; and conventional radiography and fluoroscopy, 4 percent) and a small fraction from
consumer products (2 percent). The consumer product exposure category includes exposure to
members of the public from building materials, commercial air travel, cigarette smoking, mining
and agriculture products, combustion of fossil fuels, highway and road construction materials,
and glass and ceramic. The industrial, security, medical, education, and research exposure
category includes exposure to the members of the public from nuclear power generation; DOE
installation; decommissioning and radioactive waste; industrial, medical, education, and

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research activities; contact with nuclear medicine patients; and security inspection systems. The
occupational exposure category includes exposure to workers from medical, aviation,
commercial nuclear power, industry and commerce, education and research, government, the
DOE, and military installations. Radiation exposures from occupational activities, industrial,
security, medical, educational and research contribute insignificantly to the total average
effective dose equivalent.
Table 3.9-25 Average Annual Effective Dose Equivalent of Ionizing Radiation to
a Member of the U.S. Population for 2016
Source
Background (Total)
Ubiquitous background(a)
Radon and thoron
Natural(a)
Cosmic
Terrestrial
Internal
Medical(b) (Total)
Computed tomography
Nuclear medicine
Interventional fluoroscopy
Conventional radiography and fluoroscopy
Industrial, security, medical, educational and research(a)
Occupational(a)
Consumer products(a)
Total(c)

EDE (mrem)
311

EDE Percent of
Total
56

228

41

33
21
29
229

6
4
5
41

140
41
26
22

25
7
5
4

0.3
0.5
13
553.8

0.05
0.09
2
100

EDE = effective dose equivalent; mrem = millirem.
(a) NCRP 2009.
(b) NCRP 2019. This NCRP updates the contribution from medical exposure due to changes in how procedures are
conducted through the Image Wisely and Image Gently campaigns.
(c) Total includes background, medical, industrial, security, medical, and education research, occupational, and
consumer products sources.

3.9.1.3.5 Inadvertent Liquid Radioactive Releases
As mentioned before, all commercial nuclear power plants routinely release radioactive material
to the environment in the form of liquids and gases in accordance with regulations (Table 3.9-2).
Each year, plant operators submit an effluent release report that documents the amount of
radioactive material released to the environment during the year. This report also includes the
public dose impact from the releases. Plant operators also conduct environmental monitoring in
the vicinity of the plant and submit an environmental monitoring report every year to the NRC.
All licensees must comply with the existing requirements to monitor and report effluents that are
discharged, including abnormal discharges that may migrate offsite. A discussion of the
historical inadvertent (unplanned) releases and the findings of the task force designated to
conduct a lessons learned review following the inadvertent releases of tritium at the Braidwood,
Indian Point, Byron, and Dresden sites is presented in Section 3.5.2.2.

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3.9.1.4

Radiation Health Effects Studies

Radiation health effects have been the subject of published studies (e.g., Boice et al. 2005;
FDOH 2001; IDPH 2000, 2006, 2012; Talbott et al. 2000), and a discussion of some of these
and other studies is presented in Section 3.9.1.3, Radiation Health Effects Studies, of the
2013 LR GEIS and is incorporated here by reference. The NRC is not aware of any studies that
are accepted by the scientific community that show a correlation between radiation dose from
nuclear power facilities and cancer incidence in the general public. Since 2008, Canada,
France, Germany, Great Britain, Spain, and Switzerland have all conducted epidemiological
studies near nuclear facilities within their borders to address public health concerns. These
studies have generally found no association between nuclear facility operations and increased
cancer risks to the public that are attributable to the releases or radiation exposure
(NRC 2015g).
3.9.1.4.1 Risk Estimates from Radiation Exposure
In estimating the health effects resulting from both occupational and offsite radiation exposures
as a result of operating nuclear power facilities, the normal probability coefficients for stochastic
effects recommended by the ICRP (ICRP 1991) were used. The coefficients consider the most
recent radiobiological and epidemiological information available and are consistent with the
United Nations Scientific Committee on the Effects of Atomic Radiation. The coefficients used
(Table 3.9-26) are the same as those published by ICRP in connection with a revision of its
recommendations (ICRP 1991). Excess hereditary effects are listed separately because
radiation-induced effects of this type have not been observed in any human population, as
opposed to excess malignancies that have been identified among populations receiving
instantaneous and near-uniform exposures in excess of 10 rem.
Table 3.9-26 Nominal Probability Coefficients Used in ICRP (1991)(a)
Health Effect
Fatal cancer
Hereditary

Occupational
4
0.8

Public
5
1.3

(a) Estimated number of excess effects among 10,000 people receiving 10,000 person-rem. Coefficients are based
on “central” or “best” estimates.
Source: ICRP 1991.

In 2006, the National Research Council’s Advisory Committee on the Biological Effects of
Ionizing Radiation (BEIR) published BEIR VII, entitled Health Risks from Exposure to Low
Levels of Ionizing Radiation (National Research Council 2006).
BEIR VII provides estimates of the risk of incidence and mortality for males and females. If the
total fatal cancer risk is the sum of cancer deaths from all solid cancers and leukemia, then the
fatal cancer risk coefficient for the general public would be 6 × 10-4/person-rem. The fatal cancer
risk for the general public based on ICRP is 5 × 10-4/person-rem (Table 3.9-26). There is a
difference of approximately 20 percent in the fatal cancer risk coefficient based on ICRP
recommendation and the BEIR VII report. The difference of 20 percent is within the margin of
uncertainty associated with these estimates.
The NRC completed a review of the BEIR VII report and documented its findings in the
Commission paper SECY-05-0202, Staff Review of the National Academies Study of the Health
Risks from Exposure to Low Levels of Ionizing Radiation (BEIR VII), dated October 29, 2005
(NRC 2005g). In this paper, the NRC concluded that the findings presented in the BEIR VII

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report agree with the NRC’s current understanding of the health risks from exposure to ionizing
radiation. The NRC agreed with the BEIR VII report’s major conclusion that current scientific
evidence is consistent with the hypothesis that there is a linear, no-threshold dose response
relationship between exposure to ionizing radiation and the development of cancer in humans.
In addition to the BEIR VII paper, NCRP also published Commentary No. 27 in May 2018
providing a critical review of epidemiologic studies mostly published within the past ten years.
NCRP concluded that the recent epidemiologic studies, along with judgements by other national
and international scientific committees, support the continued use of the linear-non threshold
model for radiation protection (NCRP 2018). The NRC has determined that the linear, nothreshold model continues to provide a sound regulatory basis for minimizing the risk to
unnecessary radiation exposure to both members of the public and radiation workers; three
petitions to move away from the linear, no-threshold model were denied in 2021 (86 FR 45923).
This conclusion is consistent with the process the NRC uses to develop its standards of
radiological protection. Therefore, the NRC’s regulations continue to be adequately protective of
public health and safety and the environment.
If an occupational worker is exposed at 10 CFR Part 20 dose limits for 1 year, the probability of
developing fatal cancer from exposure due to an operating nuclear reactor is equal to 2 × 10-3
based on ICRP recommendations. However, the average individual worker doses are much less
than the dose limits (see Table 3.9-5), and, at the doses observed between 2006 and 2020, the
probability of developing fatal cancer would be in the range of 2.8 × 10-5 to 6.0 × 10-5. If a
member of the public is exposed at 40 CFR Part 190 dose limits, the probability of developing
fatal cancer (based on ICRP recommendations) from exposure resulting from operating a
nuclear reactor is equal to 1.25 × 10-5. Radiation doses to nuclear power plant workers and
members of the public from the current operation of nuclear power plants have been examined,
and the radiation doses were found to be well within design objectives and regulations in each
instance.
3.9.2

Nonradiological Hazards

Nonradiological hazards, such as chemical, biological, EMFs, and physical hazards, are not
unique to nuclear power plants and can occur in many types of industrial facilities. However,
certain nonradiological hazards can be enhanced by physical plant elements or characteristics
of nuclear power plants, which this section will discuss.
While nonradiological hazards can be minimized when workers adhere to safety standards and
use appropriate protective equipment, fatalities and injuries from accidents can still occur. Risk
to members of the public can also be minimized when adhering to safety standards. See
Section 3.3 for information on air quality and noise, Section 3.5 for information on water
resources, Section 3.11 for information on waste management, and Appendix E for postulated
accidents. Adherence to environmental standards for these resource areas is important to
maintaining nonradiological public and occupational health.
The Occupational Safety and Health Administration (OSHA) is responsible for developing and
enforcing workplace safety regulations. OSHA’s mission is to ensure safe and healthful working
conditions. OSHA was created by the Occupational Safety and Health Act of 1970
(29 USC 651 et seq.). With specific regard to nuclear power plants, hazards which result in an
occupational risk, but do not affect the safety of licensed radioactive materials, are under the
statutory authority of OSHA rather than the NRC as set forth in a Memorandum of
Understanding (OSHA/NRC 2013) between the NRC and the OSHA. Additionally, the EPA,
through multiple statutes, is responsible for the regulation of hazardous chemicals that can enter

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the environment and impact members of the public. As such, nuclear power plants have
developed various programs and processes to show compliance with OSHA’s regulations,
including Chemical Safety Programs, Hazard Communication Programs, and/or an International
Organization for Standardizations 9001 Certification of Approval. The approval is not required
by OSHA or NRC but is a common industrial process that implements quality assurance by
which safety requirements are met, hazards are identified, and risks are reduced. Additionally,
nuclear power plants are required to have Federal, State, and/or local permits for releases to air
(e.g., a Title V permit), surface or groundwater water (e.g., a NPDES permit), and other local
permits and ordinances depending on the municipality.
3.9.2.1

Chemical Hazards

Chemical exposure can exist in the form of dust, fumes, fibers (solids), liquids, mists, gases, or
vapors. Chemical exposure produces different effects on the body depending on the chemical
and the amount of exposure. Chemicals can cause cancer, affect reproductive capability,
disrupt the endocrine system, or have other health effects. Acute effects from chemical
exposure occur immediately (e.g., when somebody inhales or ingests a poisonous substance
such as cyanide). Chronic or delayed effects result in symptoms such as skin rashes,
headaches, breathing difficulties, and nausea. There are multiple pathways by which humans
can be exposed to chemicals. For example, a direct pathway would be a human breathing in a
gaseous effluent or swimming in water that was contaminated by a liquid effluent. An indirect
pathway would be a human eating a fish that had absorbed a pollutant into its body or eating
crops that had been irrigated with water contaminated by a liquid effluent. In nuclear power
plants, chemical exposure can result from discharges of chlorine or other biocides,
small-volume discharges of sanitary and other liquid wastes, chemical spills, and heavy metals
leached from cooling system piping and condenser tubing. Nuclear power plant backup diesel
generators, boilers, fire pump engines, and cooling towers can also result in chemical exposure,
but are generally low emitters of criteria air pollutants (e.g., SO2, NOX, and CO) and VOCs
(e.g., such as components of petroleum fuels and hydraulic fluids [EPA 2023a]).
OSHA regulations in 29 CFR Part 1910 set enforceable permissible exposure limits for about
500 hazardous chemicals to protect workers against the health effects of exposure to hazardous
substances, including limits on the airborne concentrations of hazardous chemicals in the air
and skin contact. Most permissible exposure limits are 8-hour time-weighted averages, although
there are also ceiling and peak limits.
The EPA is responsible for the regulation of hazardous chemicals that can enter the
environment and impact members of the public. The EPA administers the following Federal acts
related to chemical contamination: the Federal Insecticide, Fungicide, and Rodenticide Act
(7 U.S.C. § 136 et seq.); Toxic Substances Control Act (15 U.S.C. § 2601 et seq.); RCRA
(42 U.S.C. § 6901 et seq.); CWA (codified as the Federal Water Pollution Control Act of 1972;
33 U.S.C. § 1251 et seq.); Safe Drinking Water Act (SDWA; 42 U.S.C. § 300f et seq.); Clean Air
Act (CAA; 42 U.S.C. § 7401 et seq.); and Comprehensive Environmental Response
Compensation, and Liability Act (42 U.S.C. § 9601 et seq.). These Acts regulate the treatment,
storage, disposal, and release of hazardous chemicals. Heavy metals (e.g., copper, zinc, and
chromium) may be leached from condenser tubing and other heat exchangers and discharged
by power plants as small-volume waste streams or corrosion products. Although all are found in
small quantities in natural waters (and many are essential micronutrients), concentrations in the
power plant discharge are controlled in the NPDES permit because excessive concentrations of
heavy metals can be toxic to aquatic organisms (see Section 3.6). The ability of aquatic
organisms to bioaccumulate heavy metals, even at low concentrations, has led to concerns

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about toxicity to both the humans and the biota that consume contaminated fish and shellfish.
For example, the bioconcentration of copper discharged from the Chalk Point plant (a fossil fuel
power plant on Chesapeake Bay) resulted in oyster “greening” (Roosenburg 1969). The
bioaccumulation of copper released from the H.B. Robinson Steam Electric Plant (Robinson)
resulted in malformations and decreased reproductive capacity among bluegill in the cooling
reservoir (Harrison 1985). At the Diablo Canyon nuclear plant, it was observed that the
concentration of soluble copper in effluent water was high during the startup of water circulation
through the condenser system after a shutdown (Harrison 1985). In all three examples of
excessive accumulation of copper (Diablo Canyon, Chalk Point, and Robinson), replacement of
the copper alloy condenser tubes with another material (e.g., titanium) eliminated the problem.
3.9.2.2

Microbiological Hazards

Microbiological hazards occur when workers or members of the public come into contact with
disease causing microorganisms, also known as etiological agents. Microbiological organisms
of concern for public and occupational health include enteric pathogens (bacteria that typically
exists in the intestines of animals and humans [e.g., Pseudomonas aeruginosa]),
thermophilic fungi, bacteria (e.g., Legionella spp. and Vibrio spp.), free-living amoebae (e.g.,
Naegleria fowleri and Acanthamoeba spp.), as well as organisms that produce toxins that affect
human health (e.g., dinoflagellates [Karenia brevis] and blue-green algae). Some of these
disease-causing organisms have been associated with the operation of nuclear power plant
cooling systems (see Section 3.9.2.2.2). Etiological agents have been referred to as
“thermophilic microorganisms” in previous NRC documents (e.g., NUREG-1555 [NRC 1999a]).
Thermophilic microorganisms have an optimum growth at temperatures of 122 degrees
Fahrenheit (°F) (50 degree Celsius [°C]) or more, a maximum temperature tolerance of up to
158°F (70°C), and a minimum tolerance of about 68°F (20°C) (Deacon 2006), although there is
some ambiguity in optimal growth temperatures defining a range for thermophiles of 104–122°F
(40–50°C) (DiGiacomo et al. 2022). This means improperly maintained cooling towers, hot
water tanks, and thermal discharges could be optimal environments for microorganisms.
Etiological agents associated with nuclear power stations also include more than just
thermophilic microorganisms and may be present in elevated numbers in unheated and heated
water systems as well as in cooling systems, receiving and source waterbodies, and site
sewage treatment facilities.
Members of the public could be exposed to microorganisms in thermal effluents at nuclear
plants that use cooling ponds, lakes, canals, or that discharge to publicly accessible surface
waters.
For this update of the LR GEIS, the SEISs published since 2013 were reviewed to determine
the level of thermophilic microbiological organism enhancement. The SEISs note that health
departments were contacted and that the health departments did not have any concerns. In all
occurrences, with the exception of Turkey Point, the NRC staff concluded that impacts to the
public from microbiological organism were SMALL. For Turkey Point, microbiological organism
impacts to members of the public was not discussed because Turkey Point discharges to a
canal cooling system not accessible by the public, with discharge to groundwater in a
saline-water environment instead of a freshwater environment. See the 2013 LR GEIS for an
additional discussion of reactor sites that were reviewed to predict the level of thermophilic
microbiological organism enhancement. The 2013 LR GEIS review did not identify hazards to
the public from enhancement of thermophilic microbiological organisms.

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OSHA has information and guidance regarding how improperly maintained human-made water
systems can serve as sources for a microbiological hazard, such as Legionella spp.
(OSHA Undated). Legionella causes Legionnaires’ disease, which is an infection of the lungs.
Legionella also causes Pontiac fever, which is a milder infection than Legionnaires’ disease and
includes fever and muscle aches but not an infection of the lungs. People get these diseases by
breathing in droplets of water in the air that contain the hazard or by drinking contaminated
water that accidentally goes into the lungs. The Centers for Disease Control and Prevention
(CDC) also has general guidelines for preventing occupational exposure to Legionella and best
practices for the control of Legionella (CDC 2021). The American National Standards
Institute/American Society of Heating, Refrigerating and Air Conditioning Engineers Standard
188-2018 documents a standard for Legionellosis and risk management for building water
systems (ASHRAE 2021). A temperature range of 77–113°F (25–45°C) is best for
Legionella spp. growth and so is the range to avoid in water systems (CDC 2018).
Acanthamoeba and Pseudomonas aeruginosa are single-cell living organisms and, much like
Legionella, thrive in stagnant or untreated water and can enter the body through the eye, skin,
or inhalation (OSHA 2015). Pseudomonas aeruginosa has an optimal growth temperature of
98.6°F (37°C) and can tolerate a temperature as high as 107.6°F (42°C) (Todar 2004).
Pseudomonas aeruginosa can cause infections in the eye, blood, or lungs (CDC 2019).
Acanthamoeba can also cause infections of the eye, skin, and central nervous system.
Naegleria fowleri, is a single-celled living organism commonly found in warm freshwater. It
thrives in warmer temperatures (up to 115°F [46°C]). Naegleria fowleri infections occur when
people go swimming or diving in warm freshwater and the amoeba travels up the nose, across
the blood-brain barrier, into the brain and destroys brain tissue. The disease is called primary
amoebic meningoencephalitis. Infections do not occur by drinking contaminated water, nor
through water vapor or aerosol droplets (CDC 2023a).
Toxins produced by some species of algae and cyanobacteria can cause harm to human health
when they grow rapidly and create blooms. In low amounts, the cyanobacteria toxin is not a
human health risk, but when the organisms cause a bloom, the toxin is harmful. Blooms occur
when water is warm (e.g., such as after a thermal discharge from a nuclear power plant),
slow-moving, and full of nutrients, such as phosphorus or nitrogen. An algae bloom can occur in
freshwater or saltwater (CDC 2023b). Cyanobacteria, also called blue-green algae, are a kind
of single-celled organism called phytoplankton. Exposure can be through skin contact, drinking
water containing the cyanobacteria, breathing in droplets in the air that contain the algae, or
eating shellfish or fish that are contaminated with the cyanobacteria. Symptoms of
cyanobacteria exposure include stomach pain, headache, muscle weakness, dizziness,
vomiting, diarrhea, and liver damage (CDC 2022a). In saltwater, algal blooms are commonly
caused by diatoms and dinoflagellates, which are another kind of phytoplankton. Breathing in
sea spray or getting the contaminated seawater on skin can cause symptoms such as
respiratory infection, shortness of breath, throat irritation, eye irritation, skin irritation, and
asthma attacks. Eating seafood contaminated with the algae toxin can cause several illnesses,
such as neurotoxic shellfish poisoning (CDC 2022b). Based on a review of SEISs to the
LR GEIS published since 2013, the staff noted that the only occurrences of algal bloom
occurred in Lake Anna in 2018, 2019, and 2020. In 2019, Dominion, the NRC-licensee for
North Anna, stated in a letter to the Virginia Department of Health that the bloom was located in
an upper arm many miles from Outfall 001 (the primary discharge into Lake Anna) and outside
the reach of the thermal plume. Dominion did develop its own cyanobacteria sampling plan in
2018 (NRC 2021g). The Fermi 2 SEIS (NRC 2016c) noted that the NRC received public
comments regarding the role of Fermi’s effluent on algal blooms. Fermi is located halfway

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between Toledo, Ohio, and Detroit, Michigan, on the lake basin where the algal blooms have
been most prevalent. The SEIS also noted that the frequency and intensity of the blooms have
been increasing and that the Fermi discharge is warmer and contains somewhat higher
concentrations of nitrogen and phosphorus than the ambient intake water of Lake Erie. The
SEIS did conclude that the information did not contradict the conclusion of the LR GEIS which
states, “Impacts of thermal discharge on the geographic distribution of aquatic organisms are
considered to be of SMALL significance if populations in the overall region are not reduced. This
is because heat is usually dissipated rapidly from power plant discharge plumes, and heated
plumes are often small relative to the size of the receiving waterbody.” Occupational worker
exposure to biological hazards can be limited through proper maintenance of systems,
processes, and machinery, and through the use of personal protective equipment. Exposure of
members of the public can also be limited through proper maintenance of systems, processes,
and equipment, and separation from thermal discharges.
3.9.2.2.1 Studies of Microorganisms in Spent Fuel Pools
During the scoping meeting for the Calvert Cliffs Nuclear Power Plant license renewal SEIS in
1998, one member of the public raised an issue about the microorganisms that live in high
radiation and extreme heat conditions (such as within the spent fuel pool) based on the article
“Something’s Bugging Nuclear Fuel” published in Science News (Raloff 1998). The commenter
asked that consideration be given to these types of organisms, the possibility of their mutation,
and consequences if they escaped from the plant into the natural aquatic environment. The
NRC consulted specialists in the field; the following is a summary of their conclusions as
presented in the SEIS (NRC 1999c):
• Many types of organisms can live in the temperature range of the spent fuel pools
(100–150°F [38–66°C]).
• There is a potential for mutation in all living organisms, but microbes that have high levels of
radiation resistance have also developed extremely efficient repair systems.
• Organisms that are associated with thermal waters of the spent fuel pool are likely to die if
they are transferred into the relatively much lower water temperatures typical of surface
waters. If the organisms are truly adapted to the high temperatures typical of the spent fuel
pool, they probably would not be able to survive and compete with the indigenous
microorganisms of the relatively cold waters of the natural water sources.
The NRC concluded that microorganisms that live in high radiation and extreme heat conditions
typical of the spent fuel pool do not pose a risk to humans or the environment as discussed in
the 2013 LR GEIS.
3.9.2.2.2 Studies of Microorganisms in and Around Cooling Towers
In 1981, cooling water systems at 11 nuclear power plants and associated control source waters
were studied for the presence of thermophilic free-living amoebae, including Naegleria fowleri.
The presence of pathogenic Naegleria fowleri in these waters was tested, and while all but one
test site was positive for thermophilic free-living amoebae, only two test sites were positive for
pathogenic Naegleria fowleri. Pathogenic Naegleria fowleri were not found in any control source
waters (Tyndall 1982). In addition to testing for pathogenic amoebae in cooling water, testing
for the presence of Legionella spp. was also done (Tyndall 1982). The concentrations of
Legionella spp. in these waters were determined. In general, the artificially heated waters
showed only a slight increase (i.e., no more than tenfold) in concentrations of Legionella spp.

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relative to source water. In a few cases, source waters had higher levels than did heated waters.
Infectious Legionella spp. were found in 7 of 11 test waters and 5 of 11 control source waters.
Subsequently, a more detailed study of Legionella spp. in the environs of coal-fired power plants
was undertaken to determine the distribution, abundance, infectivity, and aerosolization of
Legionella spp. in power plant cooling systems (Tyndall 1983; Christensen et al. 1983;
Tyndall 1985). This study found that positive air samples did not occur often at locations that
were not next to cleaning operations, which suggests that aerosolized Legionella spp.
associated with downtime procedures have minimal impact beyond these locations. Even within
plant boundaries, detectable airborne Legionella spp. appear to be confined to very limited
areas. In these areas, however, the more contact individuals have with the most concentrated
Legionella spp. populations, particularly if they become aerosolized (as they do in some
downtime operations), the more likely it is that workers are exposed.
Another study suggested that Legionella-like amoebal pathogens may be an unrecognized
significant cause of respiratory disease (Berk et al. 2006). In this study, the occurrence of
infected amoebae in water, biofilm, and sediment samples from 40 cooling towers (non-nuclear
sites) and 40 natural aquatic environments were compared. The natural samples were collected
from rivers, creeks, lakes, and ponds from Tennessee, Kentucky, New Jersey, Florida, and
Texas. The cooling tower samples were collected from industries, hospitals, municipal buildings,
universities, and other public sites from Tennessee, Kentucky, and Texas. The infected
amoebae were found in 22 cooling tower samples and 3 natural samples. According to this
study, the probability of infected amoebae occurring in cooling towers is 16 times higher than in
natural environments.
3.9.2.3

Electromagnetic Fields (EMFs)

EMFs are generated by any electrical equipment. All nuclear power plants have electrical
equipment and power transmission systems associated with them. Power transmission systems
consist of switching stations (or substations) located on the plant site and the transmission lines
needed to connect the plant to the regional electrical distribution grid. Transmission lines
operate at a frequency of 60 Hz (60 cycles per second), which is low compared with the
frequencies of 55 to 890 MHz for television transmitters and 1,000 MHz and greater for
microwaves.
Electric and magnetic fields, collectively referred to as the EMF, are produced by operating
transmission lines. Electric fields are produced by voltage, and their strength increases with
increases in voltage. An electric field is present as long as equipment is connected to the source
of electric power. The unit of electric field strength is V/m or kV/m (1 kV/m = 1,000 V/m). A
magnetic field is produced from the flow of current through wires or electrical devices, and its
strength increases as the current increases. The unit of magnetic field strength is gauss (G),
milligauss (mG), or tesla (T). One tesla equals 10,000 G and 1 G equals 1,000 mG.
Occupational workers or members of the public near transmission lines may be exposed to the
EMFs produced by the transmission lines. The EMF varies in time as the current and voltage
change, so that the frequency of the EMF is the same (e.g., 60 Hz for standard alternating
current, or AC). Electrical fields can be shielded by objects such as trees, buildings, and
vehicles. Magnetic fields, however, penetrate most materials, but their strength decreases with
increasing distance from the source.

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Power lines associated with nuclear plants usually have voltages of 230 kV, 345 kV, 500 kV,
or 765 kV (a voltage occurring primarily in the eastern United States). EMF strength at
ground-level varies greatly under these lines, generally being stronger for higher-voltage lines, a
flat configuration of conductors, relatively flat terrain, terrain with no shielding obstructions
(e.g., trees or shrubs), and a closer approach of the lines to the ground. At locations where the
field strength is at a maximum, the measured values under 500-kV lines often average about
4 kV/m but sometimes exceed 6 kV/m. Maximum electric field strengths at ground-level are
9 kV/m for 500-kV lines and 12 kV/m for 765-kV lines (Lee et al. 1989).
Measured magnetic field strengths at the location of maximum values beneath 500-kV lines
often average about 70 mG. During peak electricity use, when line current is high, the field
strength may peak at 140 mG (about 1 percent or less of the time) (Lee et al. 1989).
The EMFs resulting from 60-Hz power transmission lines fall under the category of non-ionizing
radiation. Much of the general population has been exposed to power line fields since near the
turn of the 20th century. There was little concern about health effects from such exposures until
the 1960s. A series of events during the 1960s and 1970s heightened public interest in the
possibility of health effects from non-ionizing radiation exposures and resulted in increased
scientific investigation in this area (NRC 1996). Then, in 1979, results of an epidemiological
study suggested a correlation between proximity to high-current wiring configurations and
incidence of childhood leukemia (Wertheimer and Leeper 1979). This report resulted in
additional interest and scientific research; however, no consistent evidence linking harmful
effects with 60-Hz exposures has been presented. Additionally, many subsequent studies have
been conducted on the exposure to EMF sources and have concluded that current evidence
does not support the existence of any health consequences from EMFs resulting from 60-Hz
power transmission lines (WHO 2016, NIOSH 1996, NIEHS 2002).
There are no U.S. Federal standards limiting residential or occupational exposure to EMFs from
power lines, but some States, such as Florida, Minnesota, Montana, New Jersey, New York, and
Oregon, have set electric field and magnetic field standards for transmission lines (NIEHS 2002).
A voluntary occupational standard has been set for EMFs by the International Commission on
Non-Ionizing Radiation Protection. For occupational workers who are exposed to 60 Hz (power
lines), the electric field standard is 8.3 kV/m and the magnetic field standard is 4,200 mG, while
for the general public who are exposed to 60 Hz, the electrical field standard is 4.2 kV/m and the
magnetic field standard is 833 mG (ICNIRP 1998). The National Institute of Occupational Safety
and Health does not consider EMFs to be a proven health hazard (NIOSH 1996).
3.9.2.4

Physical Hazards

A physical hazard is an action, agent or condition that can cause harm upon contact. Physical
actions could include slips, trips, and falls from height. Physical agents could include noise,
vibration, and ionizing radiation. Physical conditions could include high heat, cold, pressure,
confined space, or psychosocial issues, such as work-related stress. Power plant and
maintenance workers could be working under potentially hazardous physical conditions
(e.g., excessive heat, cold, and pressure), including electrical work, power line maintenance,
and repair work.
Table 3.9-27 lists the total number of fatal occupational injuries that occurred in 2021 in different
industry sectors. For the utility sector, of which the nuclear industry is a part, 36 workers
suffered fatal occupational injuries. The rate of fatal injuries in the utility sector was less than the
rate in the construction; transportation and warehousing; agriculture, forestry, fishing, and

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hunting; wholesale trade; and mining sectors. Table 3.9-28 lists the incidence rates of nonfatal
occupational injuries and illnesses in different utilities for 2021. The incidence rate of nonfatal
occupational injuries and illnesses is lowest for nuclear electric power generation, followed by
electric power generation.
Table 3.9-27 Number and Rate of Fatal Occupational Injuries by Industry Sector in 2021
Industry Sector
Construction
Transportation and warehousing
Agriculture, forestry, fishing, and hunting
Manufacturing
Retail trade
Leisure and hospitality
Other services (excluding Public
Administration)
Wholesale trade
Educational and health services
Mining, quarrying, oil, and gas extraction
Financial activities
Information
Utilities(a)
Electric power generation, transmission,
and distribution(b)
Electric power generation(c)
Electric power transmission, control, and
distribution
Water, sewage, and other system
All sectors

Number
986
976
453
383
263
243
242

Rate (per 100,000 employees)
9.4
14.5
19.5
2.6
1.9
2.4
3.8

177
167
95
97
36
36
25

5.1
0.7
N/A
N/A
N/A
N/A

7
16
6
5,190

N/A
N/A
N/A
N/A
3.6

N/A = not available.
(a) The numbers of fatalities from transportation and exposure to harmful substances or the environment were 12
and 14, respectively.
(b) The numbers of fatalities from transportation and exposure to harmful substances or the environment were 6 and
12, respectively.
(c) The numbers of fatalities from exposure to harmful substances or the environment was 3.
Source: BLS 2022a; BLS Undated-a, BLS 2022c.

Table 3.9-28 Incidence Rate of Nonfatal Occupational Injuries and Illnesses in Different
Utilities in 2021
Utility
Utilities
Electric power generation, transmission, and distribution
Electric power generation
Fossil Fuel electric power generation
Nuclear electric power generation
Electric power transmission, control, and distribution
Natural gas distribution
Water, sewage, and other system
Overall

Rate (per 100 Employees)
1.7
1.5
1.2
1.8
0.2
1.8
1.8
2.4
2.9

Source: BLS 2022b.

Table 3.9-29 lists the number and rate of fatal occupational injuries that occurred in 2021 for
listed occupations. The occupational safety and health hazards issue is generic to all types of
electrical generating stations, including nuclear power plants, and is of small significance if the
workers adhere to safety standards and use protective equipment.
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Table 3.9-29 Number and Rate of Fatal Occupational Injuries for Selected Occupations
in 2021
Occupation
Fishing and hunting workers
Aircraft pilots and flight engineers
Logging workers
Structural iron and steel workers
Refuse and recyclable material collectors
Drivers/sales workers and truck drivers
Helpers, construction trades

Number
23
68
43
14
23
1,032
15

Rate per 100,000 FullTime Equivalent Workers
75.2
48.1
82.2
36.1
27.9
28.8
22.9

Source: BLS Undated-b.

3.9.2.4.1 Electric Shock Hazards
In-scope transmission lines are those lines that connect the plant to the first substation of the
regional electric grid. This substation is frequently, but not always, located on the plant property.
The greatest hazard from a transmission line is direct electrical contact with the conductors. The
electrical contact can occur without physical contact between a grounded object and the
conductor (e.g., when arcing occurs across an air gap) (BPA 2022). The electric field created by
a high-voltage line extends from the energized conductors to other conducting objects, such as
the ground, vegetation, buildings, vehicles, and persons. Potential field effects can include
induced currents, steady-state current shocks, spark-discharge shocks, and, in some cases,
field perception and neurobehavioral responses.
The shock hazard issue is evaluated by referring to the National Electric Safety Code (NESC).
The purpose of the NESC is the practical safeguarding of persons during the installation,
operation, or maintenance of electric supply and communication lines and associated
equipment. The NESC contains the basic provisions that are considered necessary for the
safety of employees and the public under the specified conditions (IEEE SA 2017, 2023).
Primary shock currents are produced mainly through direct contact with conductors and have
effects ranging from a mild tingling sensation to death by electrocution. Tower designs preclude
direct public access to the conductors. Secondary shock currents are produced when humans
make contact with (1) capacitively charged bodies, such as a vehicle parked near a
transmission line, or (2) magnetically linked metallic structures, such as fences near
transmission lines. A person who contacts such an object could receive a shock and experience
a painful sensation at the point of contact. The intensity of the shock depends on the EMF
strength, the size of the object, and how well the object and the person are insulated from
ground.
Design criteria that limit hazards from steady-state currents are based on the NESC, which
requires that utility companies design transmission lines so that the short-circuit current to
ground, produced from the largest anticipated vehicle or object, is limited to less than
5 milliamperes (mA) (IEEE SA 2017, 2023).
Historically, in the licensing process for the earlier licensed nuclear power plants, the issue of
electrical shock safety was not addressed. Additionally, some nuclear power plants that
received operating licenses with a stated transmission line voltage may have chosen to upgrade
the line voltage for reasons of efficiency, possibly without reanalysis of induction effects. Also,
since the initial NEPA review for those utilities that evaluated potential shock situations under

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the provision of the NESC, land use may have changed, resulting in the need for a reevaluation
of this issue. Electrical shock potential is minimized for transmission lines that are operated in
adherence with the NESC.
A review of the SEISs to the LR GEIS published since 2013, found that 3 transmission lines at
South Texas did not meet the criteria defined by NESC (NRC 2013b), nor did nine transmission
line spans at Sequoyah (NRC 2015f). Regarding South Texas, the staff concluded that the three
transmission lines exceeded the NESC criterion by a small percentage. The locations where the
lines exceed the standard are in remote locations or are on private property, and the applicant
considered potential mitigation measures to reduce or avoid adverse impacts from electric
shock. In the case of Sequoyah, TVA committed to upgrades to correct the deficiencies in
transmission lines that did not meet the NESC criteria for induced current. The transmission
lines discussed in South Texas and Sequoyah span areas beyond what was termed in the
2013 LR GEIS as in-scope transmission lines.

3.10 Environmental Justice
Under Executive Order 12898, “Federal Actions to Address Environmental Justice in Minority
Populations and Low-Income Populations” (59 FR 7629), Federal agencies are responsible for
identifying and addressing, as appropriate, disproportionately high and adverse human health
and environmental effects of their programs, policies, and activities on minority and low-income
populations. Although independent agencies, like the NRC, were only requested, rather than
directed, to comply with Executive Order 12898, the NRC Chairman, in a March 1994 letter to
the President, committed the NRC to endeavoring to carry out its measures “ … as part of
NRC’s efforts to comply with the requirements of NEPA” (NRC 1994). In 2004, the Commission
issued its Policy Statement on the Treatment of Environmental Justice Matters in NRC
Regulatory and Licensing Actions (69 FR 52040), which states, “The Commission is committed
to the general goals set forth in Executive Order 12898, and strives to meet those goals as part
of its NEPA review process.”17
Executive Order 12898, Federal Actions to Address Environmental Justice in Minority
Populations and Low-Income Populations
“Each Federal agency, whenever practicable and appropriate, shall collect, maintain, and
analyze information assessing and comparing environmental and human health risks borne by
populations identified by race, national origin, or income. To the extent practical and
appropriate, Federal agencies shall use this information to determine whether their programs,
policies, and activities have disproportionately high and adverse human health or
environmental effects on minority populations and low-income populations.”

17

In April 2021, the Commission issued Staff Requirements Memorandum M210218B (NRC 2021s)
directing the NRC staff to conduct a systematic review of how agency programs, policies, and activities
address environmental justice. The NRC staff submitted its assessment and recommendations in
SECY-22-0025, “Systematic Review of How Agency Programs, Policies, and Activities Address
Environmental Justice” to the Commission in March 2022 (NRC 2022h). The NRC staff’s review
considered the environmental justice practices of other Federal, State, and Tribal agencies, evaluated the
adequacy of the NRC’s Environmental Justice Policy Statement, and assessed whether the NRC should
address environmental justice beyond the agency’s current practice limited to National Environmental
Policy Act environmental reviews.

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The Council on Environmental Quality provides the following information in Environmental
Justice: Guidance Under the National Environmental Policy Act (CEQ 1997b):
• Disproportionately high and adverse human health effects. In determining whether
human health effects are disproportionately high and adverse, agencies should consider to
the extent practicable: “(a) Whether the health effects, which may be measured in risks and
rates, are significant (as employed by NEPA), or above generally accepted norms. Adverse
health effects may include bodily impairment, infirmity, illness, or death; and (b) Whether the
risk or rate of hazard exposure by a minority population, low-income population, or Indian
Tribe to an environmental hazard is significant (as employed by NEPA) and appreciably
exceeds or is likely to appreciably exceed the risk or rate to the general population or other
appropriate comparison group; and (c) Whether health effects occur in a minority population,
low-income population, or Indian Tribe affected by cumulative or multiple adverse exposures
from environmental hazards.”
• Disproportionately high and adverse environmental effects. In determining whether
environmental effects are disproportionately high and adverse, agencies should consider to
the extent practicable: “(a) Whether there is or will be an impact on the natural or physical
environment that significantly (as employed by NEPA) and adversely affects a minority
population, low-income population, or Indian Tribe. Such effects may include ecological,
cultural, human health, economic, or social impacts on minority communities, low-income
communities, or Indian Tribes when those impacts are interrelated to impacts on the natural
or physical environment; and (b) Whether environmental effects are significant (as employed
by NEPA) and are or may be having an adverse impact on minority populations, low-income
populations, or Indian Tribes that appreciably exceeds or is likely to appreciably exceed those
on the general population or other appropriate comparison group; and (c) Whether the
environmental effects occur or would occur in a minority population, low-income population, or
Indian Tribe affected by cumulative or multiple adverse exposures from environmental
hazards.”
The environmental justice analysis identifies minority populations, low-income populations, and
Indian Tribes that could be affected by continued reactor operations and refurbishment activities
at a nuclear power plant. The following Council on Environmental Quality definitions of minority
individuals and populations and low-income populations are used:
• Minority. Individual(s) who identify themselves as members of the following population
groups: Hispanic or Latino, American Indian or Alaska Native, Asian, Black or African
American, Native Hawaiian or Other Pacific Islander, or two or more races meaning
individuals who identified themselves as being a member of two or more races, for example,
Hispanic and Asian.
• Minority population. Minority populations are identified when (1) the minority population of
an affected area exceeds 50 percent or (2) the minority population percentage of the affected
area is meaningfully greater than the minority population percentage in the general population
or other appropriate unit of geographic analysis. Minority populations may be communities of
individuals living in close geographic proximity to one another or they may be a
geographically dispersed or transient set of individuals, such as migrant workers or Native
Americans, who, as a group, experience common conditions with regard to environmental
exposure or environmental effects. The appropriate geographic unit of analysis may be a
political jurisdiction, county, region, or State, or some other similar unit that is chosen so as
not to artificially dilute or inflate the affected minority population.

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• Low-income population. Low-income population is defined as individuals or families living
below the annual statistical poverty threshold as defined by the U.S. Census Bureau’s Current
Population Reports, Series P-60 on Income and Poverty (CEQ 1997b). Low-income
populations may be communities of individuals living in close geographic proximity to one
another, or they may be a set of individuals, such as migrant workers or Native Americans,
who, as a group, experience common conditions of environmental exposure or effect.
Consistent with the definitions used in the public and occupational health and safety analysis
presented in Section 3.9, affected populations are defined as minority and low-income
populations who reside within a 50 mi (80 km) radius of a nuclear plant. Data on minority and
low-income individuals are collected and analyzed at the census block group or tract level.18
The presence of minority populations, low-income populations, and Indian Tribes within 50 mi
(80 km) of each nuclear power plant varies considerably depending on the location of Tribal
lands, population trends, and regional economic activity. Nuclear power plants in southern and
southwestern States have been found to have larger minority populations, including Browns
Ferry, Brunswick, Catawba, Joseph M. Farley Nuclear Plant (Farley), North Anna, Robinson,
Summer, and Surry nuclear plants. Nuclear power plants near metropolitan areas generally
have larger minority and low-income populations, including Dresden and Ginna nuclear plants.
Section 4-4 of Executive Order 12898 directs Federal agencies, whenever practical and
appropriate, to collect and analyze information on the consumption patterns of populations who
rely principally on fish and/or wildlife for subsistence and to communicate the risks of these
consumption patterns to the public. Consideration is given to determine the means by which
these populations could be disproportionately affected by the continued operation of a nuclear
power plant. Consumption patterns (e.g., subsistence agriculture, hunting, and fishing) and
certain resource dependencies often reflect the traditional or cultural practices of minority
populations, low-income populations, and Indian Tribes.
In assessing human health effects, the NRC examines radiological risk from consumption of
fish, wildlife, and local produce; exposure to radioactive material in water, soils, and vegetation;
and the inhalation of airborne radioactive material during nuclear power plant operation. To
assess the effect of nuclear reactor operations, licensees are required to collect samples from
the environment, as part of their REMP. These samples are analyzed annually for radioactivity
to assess the impact of nuclear power plant operations.

3.11 Waste Management and Pollution Prevention
As part of their normal operations and as a result of equipment repairs and replacements due to
normal maintenance activities, nuclear power plants routinely generate both radioactive and
nonradioactive wastes. Nonradioactive wastes include hazardous and nonhazardous wastes.
There is also a class of waste, called mixed waste, that is both radioactive and hazardous. The
systems used to manage (i.e., treat, store, and dispose of) these wastes are described in
Sections 3.1.4 and 3.1.5. The basic characteristics and current disposition paths for these waste
18

A census block group is a combination of census blocks, which are statistical subdivisions of a census
tract. A census block is the smallest geographic entity for which the U.S. Census Bureau collects and
tabulates decennial census information. A census tract is a small, relatively permanent statistical
subdivision of counties delineated by local committees of census data users in accordance with U.S.
Census Bureau guidelines for the purpose of collecting and presenting decennial census data. Census
block groups are subsets of census tracts (USCB Undated).

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streams are discussed in Section 3.11.1 for radioactive waste, 3.11.2 for hazardous waste,
3.11.3 for mixed waste, and 3.11.4 for nonradioactive nonhazardous waste. Waste minimization
and pollution prevention measures commonly employed at nuclear power plants are reviewed in
Section 3.11.5.
3.11.1 Radioactive Waste
There are two types of radiological wastes that could be associated with a commercial reactor:
LLW and spent nuclear fuel. Disposition of licensed materials is regulated in accordance with
10 CFR Part 20 Subpart K. The NRC requires that all licensees implement measures to
minimize, to the extent practicable, the generation of radioactive waste (10 CFR 20.1406).
These wastes are described in the sections below.
Definitions of Radioactive Wastes Associated with Commercial Nuclear Power Plants
• Low-level waste: Radioactive material that (1) is not high-level radioactive waste, spent
nuclear fuel, or by-product material (as defined in Section 11e(2) of the AEA of 1954
[42 U.S.C. 2014(e)(2)]) and (2) is classified by the NRC, consistent with existing law, as
low-level radioactive waste (as defined in the Low-Level Radioactive Waste Policy
Amendments Act of 1985, as amended, Public Law 99-240; 42 U.S.C. § 2021b et seq.).19
• Spent nuclear fuel: Fuel that has been withdrawn from a nuclear reactor following
irradiation, the constituent elements of which have not been separated by reprocessing (as
included in the Nuclear Waste Policy Act of 1982, as amended, Public Law 97-425
[42 U.S.C. § 10101 et seq.]).
3.11.1.1

Low-Level Radioactive Waste

The Commission’s licensing requirements for the land disposal of LLW are set forth in 10 CFR
Part 61, “Licensing Requirements for Land Disposal of Radioactive Waste.” Part 61 defines
LLW as “radioactive waste not classified as high-level radioactive waste [HLRW], transuranic
[TRU] waste, spent nuclear fuel, or by-product material as defined in paragraphs (2), (3), and
(4) of the definition of by-product material set forth in § 20.1003 of this chapter.”20 The NRC’s
definition of LLW is included in 10 CFR 61.55. Depending on the types and concentrations of
radionuclides in the waste, the NRC classifies LLW as belonging to Class A, Class B, Class C,
or greater-than-Class C (GTCC). Class A wastes generally contain short-lived radionuclides at
relatively low concentrations, whereas the half-lives and concentrations of radionuclides in the
Class B and C wastes are progressively higher. In addition, Class B wastes must meet more
rigorous requirements with regard to their form to ensure they remain stable after disposal
(e.g., by adding chemical stabilizing agents such as cement to the waste or placing the waste in
a disposal container or structure that provides stability after disposal). Class C wastes must not
only meet the more rigorous requirements above but also require the implementation of
additional measures at the disposal facility to protect against inadvertent intrusion (e.g., by
increasing the thickness and hardness of the cover over the waste disposal cell). Wastes
containing radionuclides at concentrations that are higher than what is allowed for Class C
wastes are classified as GTCC. GTCC is LLW with concentrations of radionuclides that exceed
the limits established by the Commission for Class C LLW (NRC 2019e). Under the NRC’s
19

The Low-Level Radioactive Waste Policy Amendments Act (Public Law 99-240) superseded, in its
entirety, an earlier law, the Low-Level Radioactive Waste Policy Act of 1980 (Public Law 96-573).
20 10 CFR 61.2 (definition of “waste”).

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regulations, GTCC waste is considered to be generally unacceptable for near-surface disposal
and must be disposed of in a geologic repository unless the Commission approves, on a
case-by-case basis, disposal of such waste in a disposal site licensed pursuant to 10 CFR
61.55(a)(2)(iv). Disposal of GTCC waste is the responsibility of the DOE (42 U.S.C. § 2021b
et seq.). DOE prepared an EIS to evaluate the various alternatives for disposing of these wastes
(DOE 2016) and presented the alternatives for disposal of GTCC LLW and GTCC-like waste
(DOE 2017).
LLW generated at nuclear power plants generally consists of air filters, cleaning rags, protective
tape, paper and plastic coverings, discarded contaminated clothing, tools, equipment parts, and
solid laboratory wastes (all of these are collectively known as dry active waste) and wet wastes
that result during the processing and recycling of contaminated liquids at the plants. Wet wastes
generally consist of evaporator bottoms, spent demineralizer or ion exchange resins, and spent
filter material from the equipment drain, floor drain, and water cleanup systems. The wet wastes
are generally solidified, dried, or dewatered to make them acceptable at a disposal site. Some
plants perform these operations onsite, while others ship their waste to a third-party vendor
offsite for processing before it is sent to a disposal facility. The radioactivity can range from just
above the background levels found in nature to very highly radioactive. LLW that contains
radionuclides that have shorter decay times can be stored onsite by licensees until it can be
released in accordance with 10 CFR Part 20, Subpart K. LLW that contains radionuclides that
have longer decay times can be stored onsite until material inventory amounts are large enough
for shipment to a LLW disposal site. The transportation and disposal of solid radioactive wastes
are performed in accordance with the applicable requirements of 10 CFR Part 71 and
10 CFR Part 61, respectively.
LLW shipments from nuclear power plants to disposal facilities or waste processing centers and
from waste processing centers to disposal facilities are generally made by trucks. Wastes are
segregated and packaged by class. For load-leveling purposes, the wastes may be stored
onsite at the plant temporarily before shipment offsite. Construction and operation of any LLW
storage areas and any activities related to storage and processing of LLW onsite, including the
preparation of waste for shipment and loading on vehicles before shipment, are carried out in
accordance with the licensing requirements imposed by the NRC. All such operations are
accounted for when the applicants prepare their annual radioactive effluent release reports to
demonstrate compliance with the applicable Federal standards and requirements. The primary
standards applicable to all the power plants are contained in 10 CFR Part 20, 40 CFR Part 190,
and Appendix I to 10 CFR Part 50.
The Low-Level Radioactive Waste Policy Amendments Act of 1985 (Public Law 99-240) gave
States the responsibility for disposal of the LLW generated at commercial facilities within their
states. As an incentive for States to manage waste on a regional basis, Congress consented to
the formation of interstate agreements known as compacts, and it granted compact member
States the authority to exclude LLW from States that are members of other compacts or
unaffiliated with a compact. There are currently four operating disposal facilities in the United
States that are licensed to accept LLW from commercial facilities (including nuclear power
plants) (NRC 2020h). They are located in Clive, Utah; Andrews County, Texas; Barnwell, South
Carolina; and near Richland, Washington. The EnergySolutions disposal facility in Clive, Utah,
is licensed by the State of Utah to accept Class A LLW from all regions of the United States.
The Waste Control Specialists, LLC site in Andrews County, Texas, is licensed by the State of
Texas to accept Class A, B, and C LLW from the Texas Compact generators (Texas and
Vermont) and from outside generators with permission from the Texas Compact.
EnergySolutions Barnwell Operations located near Barnwell, South Carolina, accepts waste

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from the Atlantic Compact States (Connecticut, New Jersey, and South Carolina) and is
licensed by the State of South Carolina to dispose of Class A, B, and C LLW. U.S. Ecology,
located near Richland, Washington, accepts LLW from the Northwest and Rocky Mountain
Compact States (Washington, Alaska, Hawaii, Idaho, Montana, Oregon, Utah, Wyoming,
Colorado, Nevada, and New Mexico) and is licensed by the State of Washington to dispose of
Class A, B, and C waste.
Annual quantities of LLW generated at the nuclear power plants vary from year to year,
depending on the number of maintenance activities undertaken and the number of unusual
occurrences taking place in that year. However, on average, the volume and radioactivity of
LLW generated at a PWR was approximately 10,600 ft3 (300 m3) and 1,000 Ci (3.7 × 1013 Bq)
per year, respectively, according to the 1996 LR GEIS (Table 6.6 in NRC 1996). The annual
volume and activity of LLW generated at a BWR are approximately twice the values indicated
for a PWR. The total volume and activity of LLW generated at all the LWRs in the United States
was approximately 706,000 ft3 (20,000 m3) and 60,000 Ci (2.2 × 1015 Bq), respectively,
according to the 1996 LR GEIS (Table 6.6 in NRC 1996). Approximately 95 percent of this
waste is Class A (NEI 2007b in the 2013 LR GEIS). Table 3.11-1 and Table 3.11-2 show the
volume and activity of LLW shipped offsite per operating reactor unit from 11 power plant sites
in 2021. For example, there are two operating units at the Comanche Peak site, and the volume
and activity of LLW shipped from the Comanche Peak site in 2021 were 10,453 ft3 (296 m3) and
253 Ci (9.36 × 1012 Bq). The numbers in Table 3.11-1 and Table 3.11-2 were obtained from the
annual radioactive effluent release reports issued by each plant for 2021.
Almost all of the LLW generated at the reactor sites is shipped offsite, either directly to a
disposal facility or to a processing center for volume reduction or another type of treatment
before being sent to a disposal site. The number of shipments leaving each reactor site varies
but generally ranges from a few to about 100 per year. 10 CFR Part 20, Subpart K, discusses
the various means by which the licensees may dispose of their radioactive waste.
Table 3.11-1 Solid Low-Level Radioactive Waste Shipped Offsite per Reactor from Select
Pressurized Water Reactor Power Plant Sites in 2021(a)
Nuclear Power Plant
Comanche Peak
D.C. Cook
Palo Verde 1–3
Robinson
Seabrook
Surry

Volume (m3)
296
350
777
51
18
435

Activity (Ci)
253
119
280
50
<1
301

Number of
Shipments
9
16
43
4
3
14

Number of
Reactors
2
1
3
2
1
2

Ci = curies; m3= cubic meter.
(a) Annual effluent release reports. The radiological environmental monitoring reports can also be accessed by
navigating the reactor webpage for each site on the NRC website; effluent reports and environmental reports are
available through the “Plant Environmental Report” section of the key documents.

Table 3.11-2 Solid Low-Level Radioactive Waste Shipped Offsite per Reactor from Select
Boiling Water Reactor Power Plant Sites in 2021(a)
Nuclear Power Plant
Fermi 2
Hatch
Hope Creek and Salem(b)

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Volume (m3)
1,010
1,217
499

Activity (Ci)
678
928
42

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Number of
Shipments
34
51
24

Number of
Reactors
1
2
3

Affected Environment

Nuclear Power Plant
Limerick
Columbia

Volume (m3)
688
3,893

Activity (Ci)
614
632

Number of
Shipments
43
39

Number of
Reactors
1
1

Ci = curies; m3= cubic meter.
(a) Annual effluent release reports. The radiological environmental monitoring reports can also be accessed by
navigating the reactor webpage for each site on the NRC website; effluent reports and environmental reports are
available through the “Plant Environmental Report” section of the key documents.
(b) Hope Creek is a boiling water reactor but is reported with the Salem Generating Station as a joint site, so it is
included in this table.

3.11.1.2

Spent Nuclear Fuel

Spent nuclear fuel is fuel that has been withdrawn from a nuclear reactor following irradiation,
the constituent elements of which have not been separated. When spent nuclear fuel is
removed from a reactor, it is stored in racks placed in a pool (called the spent fuel pool) to
isolate it from the environment and to allow the fuel rods to cool. Licensing plans contemplate
disposal of spent fuel in a deep geological permanent repository. Siting and developing a
permanent repository is required by the Nuclear Waste Policy Act of 1982 (42 U.S.C. § 10101
et seq.). Delays in siting a permanent repository, coupled with rapidly filling spent fuel pools at
some plants, have led utilities to seek means of continued onsite storage. These include
(1) expanded pool storage, (2) dry storage, (3) longer fuel burnup to reduce the amount of spent
nuclear fuel requiring interim storage, and (4) shipment of spent nuclear fuel to other plants. Any
modification to the spent nuclear fuel storage configuration at a nuclear power plant is subject to
NRC review and approval. Each review consists of a safety and environmental review. As
part of the environmental review for such a modification, the NRC generally prepares an
environmental assessment.
Expanded pool storage options include (1) enlarging the capacity of spent fuel racks, (2) adding
racks to existing pool arrays (“dense-racking”), (3) reconfiguring spent fuel racks with
neutron-absorbing racks, and (4) employing double-tiered storage (installing a second tier of
racks above those on the spent fuel pool floor).
Dry storage involves moving the spent fuel assemblies, which have been stored in the spent
fuel pool for a certain period of time, to shielded enclosures that are air cooled. The spent
nuclear fuel is stored in the spent fuel pool to cool, typically for several years, before it may be
moved to a dry cask storage facility. In the late 1970s and early 1980s, the need for alternative
storage grew when pools at many nuclear reactors filled with stored spent fuel. Utilities looked
at options such as dry cask storage for increasing their storage capacity for spent nuclear fuel.
Dry cask storage allows spent nuclear fuel to be surrounded by inert gas inside a container
called a cask. The casks are typically steel cylinders that are either welded or bolted closed.
The steel cylinder provides a leak-proof containment for the spent nuclear fuel. Each cylinder is
surrounded by additional steel, concrete, or other material to provide radiation shielding to
workers and members of the public. Some of the cask designs can be used for both storage and
transportation.
There are various dry storage cask system designs. With some designs, the steel cylinders
containing the spent nuclear fuel are placed vertically in a concrete vault; other designs orient the
cylinders horizontally. The concrete vaults provide the radiation shielding. Other cask designs
orient the steel cylinder vertically on a concrete pad at a dry cask storage site and use both metal
and concrete outer cylinders for radiation shielding. Figure 3.11-1 shows two of the typical dry
cask storage designs. The location of the dry casks is in a facility known as an ISFSI. This is a

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facility designed and constructed for the interim storage of spent nuclear fuel, solid
reactor-related GTCC, and other radioactive materials associated with spent nuclear fuel and
reactor-related GTCC storage. The ISFSI is generally located within the same site where the
nuclear fuel is used and is licensed by the NRC under either a general license or a site-specific
license (see 10 CFR Part 72). Figure 3.11-2 shows the locations of currently licensed ISFSIs.
Longer-burnup fuel is fuel from which more energy can be obtained before it is taken out of the
reactor and declared spent. As a result of using this fuel, less spent fuel is generated for the
same amount of energy produced in a reactor.

Figure 3.11-1 Typical Dry Cask Storage Systems. Source: NRC 2020k.

Definitions of Other Wastes Associated with Commercial Nuclear Power Plants
• Hazardous Waste: A solid waste or combination of solid wastes that, because of its
quantity, concentration, or physical, chemical, or infectious characteristics, may (1) cause or
significantly contribute to an increase in mortality or an increase in serious irreversible or
incapacitating reversible illness, or (2) pose a substantial present or potential hazard to
human health or the environment when improperly treated, stored, transported, disposed of,
or otherwise managed (as defined in the Resource Conservation and Recovery Act, as
amended, Public Law 94-580 [42 U.S.C. § 6901 et seq.]).
• Mixed Waste: Waste that is both hazardous and radioactive.
• Nonradioactive Nonhazardous Waste: Waste that is neither radioactive nor hazardous.

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Figure 3.11-2 Locations of Independent Spent Fuel Storage Installations Licensed by the NRC. Source: NRC 2023c.

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3.11.2 Hazardous Waste
Hazardous waste is defined by the EPA in 40 CFR Part 261, “Identification and Listing of
Hazardous Waste” as solid waste that (1) is listed by the EPA as being hazardous; (2) exhibits
one of the characteristics of ignitability, corrosivity, reactivity, or toxicity; or (3) is not excluded by
the EPA from regulation as being hazardous.
All aspects of hazardous waste generation, treatment, transportation, and disposal are strictly
regulated by the EPA or by the States under agreement with the EPA per the regulations
promulgated under RCRA (Public Law 94-580 [42 U.S.C. § 6901 et seq.]).
The types of hazardous waste that nuclear power plants typically generate include waste paints,
lab packs, and solvents. The quantities of these wastes generated at individual plants are
highly variable but, generally, are relatively small compared to those at most other industrial
facilities that generate hazardous waste. Most nuclear power plants accumulate their hazardous
waste onsite as authorized under RCRA and transport it to a treatment facility for processing.
The remaining residues are sent to a permanent disposal facility. There are quite a few
RCRA-permitted treatment and disposal facilities throughout the United States that are used by
the owners of nuclear power plants.
A class of hazardous waste called universal waste is handled differently than hazardous waste
and includes batteries, pesticides, mercury-containing equipment, light bulbs, and aerosol cans.
Federal universal waste regulations can be found in 40 CFR Part 273. All aspects of hazardous
waste, such as generation, treatment, transportation, and disposal, are regulated by the EPA or
by States under agreements with the EPA per the regulations set forth under RCRA. RCRA also
defines categories of hazardous waste generators (EPA 2020a).
3.11.3 Mixed Waste
Mixed waste, regulated under RCRA and the AEA of 1954, as amended (42 U.S.C.
§ 2011 et seq.), is waste that is both radioactive and hazardous (EPA 2019). Mixed waste is
subject to dual regulation: by the EPA or an authorized State for its hazardous component and
by the NRC or an agreement state for its radioactivity. The types of mixed wastes generated at
nuclear power plants include organics (e.g., liquid scintillation fluids, waste oils, halogenated
organics), metals (e.g., lead, mercury, chromium, and cadmium), solvents, paints, and cutting
fluids. The quantity of mixed waste generated varies considerably from plant to plant
(NRC 1996). Overall, the quantities generated during operations are generally relatively small,
but because of the added complexity of dual regulation, it is more problematic for plant owners
to manage and dispose of mixed wastes than the other types of wastes. Similar to hazardous
waste, mixed waste is generally accumulated onsite in designated areas as authorized under
RCRA then shipped offsite for treatment as appropriate and for disposal. The only disposal
facilities that are authorized to receive mixed LLW for disposal at present are the U.S. Ecology
and the Waste Control Specialists facilities discussed under Section 3.11.1.1.
Occupational exposures and any releases from onsite treatment of these and any other types of
wastes are considered when evaluating compliance with the applicable Federal standards and
regulations: for example, 10 CFR Part 20, 40 CFR Part 190, and Appendix I to 10 CFR Part 50.

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3.11.4 Nonhazardous Waste
Nonhazardous waste is waste that is not contaminated with either radionuclides or hazardous
chemicals. These wastes include office trash, paper, wood, oils not mixed with hazardous waste
or radiological waste, and sewage. Solid wastes defined as nonhazardous by 40 CFR Part 261
are collected and disposed of in a landfill. Sanitary wastes defined as nonhazardous by 40 CFR
Part 261 are treated either at an onsite sewage treatment plant (as in the case of many largescale industrial facilities), discharged directly to a municipal sewage system for treatment, or
discharged to onsite septic tanks. The uncontaminated wastes and sewage are tested for
radionuclides before being sent offsite to make sure that there is no inadvertent contamination.
Any offsite releases from the onsite sewage treatment plants are conducted under NPDES
permits. Most plants also collect and test the stormwater runoff from their sites before
discharging it offsite. Large LWRs have nonradioactive waste management systems in place
that manage both hazardous and nonhazardous wastes. For example, boiler blowdown, water
treatment wastes, boiler metal cleaning wastes, laboratory and sampling wastes, floor and yard
drains, and stormwater runoff are all managed by these systems and are regulated by an
NPDES permit, with the exception of wastes in solid form (NRC 2013a).
3.11.5 Pollution Prevention and Waste Minimization
Waste minimization and pollution prevention are important elements of operations at all nuclear
power plants. The licensees are required to consider pollution prevention measures as dictated
by the Pollution Prevention Act (Public Law 101-508 [42 U.S.C. § 13101 et seq.]) and RCRA
(Public Law 94-580 [42 U.S.C. § 6901 et seq.]).
In addition, licensees have waste minimization programs in place that are aimed at minimizing
the quantities of waste sent offsite for treatment or disposal. Waste minimization techniques
employed by the licensees may include (1) source reduction, which includes (a) changes in
input materials (e.g., using materials that are not hazardous or are less hazardous), (b) changes
in technology, and (c) changes in operating practices and (2) recycling of materials either onsite
or offsite. For example, the licensees tend to reuse lead shielding components onsite until they
have no further use for them. The establishment of a waste minimization program is also a
requirement for managing hazardous wastes under RCRA.

3.12 Greenhouse Gas Emissions and Climate Change
3.12.1 Greenhouse Gas Emissions
Gases found in the Earth’s atmosphere that trap heat and play a role in the Earth’s climate are
collectively termed greenhouse gases (GHGs). These GHGs include carbon dioxide (CO2),
methane (CH4), nitrous oxide (N2O), water vapor (H2O), and fluorinated gases, such as
hydrofluorocarbons (HCFs), perfluorocarbons, and sulfur hexafluoride. Operations at nuclear
power plants release GHGs from stationary combustion sources (e.g., diesel generators,
pumps, diesel engines, boilers), refrigeration systems, electrical transmission and distribution
systems, and mobile sources (worker vehicles and delivery vehicles).
The Earth’s climate responds to changes in concentrations of GHGs in the atmosphere because
these gases affect the amount of energy absorbed and heat trapped by the atmosphere.
Increasing concentrations of GHGs in the atmosphere generally increase the Earth’s surface
temperature. Atmospheric concentrations of CO2, CH4, and N2O have significantly increased
since 1750 (IPCC 2013, IPCC 2023). In 2019, atmospheric concentrations of CO2 (measured at

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410 parts per million) were higher than any time in at least 2 million years (IPCC 2023).
Long-lived GHGs—CO2, CH4, N2O, and fluorinated gases—are well mixed throughout the
Earth’s atmosphere, and their impact on climate is long-lasting and cumulative in nature as a
result of their long atmospheric lifetimes (EPA 2016). Therefore, the extent and nature of climate
change is not specific to where GHGs are emitted. Carbon dioxide is of primary concern for
global climate change because it is the primary gas emitted as a result of human activities. The
sixth assessment synthesis report from the Intergovernmental Panel on Climate Change (IPCC)
states that “[i]t is unequivocal that human influence has warmed the atmosphere, ocean, and
land” (IPCC 2023). In 2019, global net GHG emissions were estimated to be 59±6.6 gigatons of
CO2 equivalents (CO2eq21), with the largest share in gross GHG emissions being CO2 from
fossil fuels combustion and industrial processes (IPCC 2023).
The EPA has determined that GHGs “may reasonably be anticipated both to endanger public
health and to endanger public welfare” (74 FR 66496). In 2009, the EPA issued a final rule
requiring the reporting of GHG emissions from facilities that directly emit 25,000 MT
(27,557 tons) of CO2eq or more per year (74 FR 56260). The 25,000 MT of CO2eq reporting
threshold EPA established in the above final rule is not an indication of what EPA considers to
be a significant (or insignificant) level of GHG emissions on a scientific basis, but a threshold
chosen by EPA for policy evaluation purposes (74 FR 56260). The Greenhouse Gas Reporting
Program captures approximately 90 percent of total U.S. GHG emissions from more than
8,000 facilities, because facilities that fall below the 25,000 MT of CO2eq/yr are not required to
report GHG emissions to the EPA. The EPA publishes GHG emission data from the
Greenhouse Gas Reporting Program via the Facility Level Information on GreenHouse Gases
Tool. The EPA also prepares an annual report, Inventory of U.S. Greenhouse Gas Emissions
and Sinks (Inventory), that estimates total GHG emissions across all sectors of the U.S.
economy by using national statistics (e.g., energy data, agricultural activities). EPA’s Inventory
is an essential tool for addressing climate change and participating in the United Nations
Framework Convention on Climate Change to compare the relative global contribution of
different emission sources and GHGs to climate change. In 2021, U.S. gross GHG emissions
totaled 6,988.8 million tons (6,340.2 million MT) of CO2eq (EPA 2023b). Carbon dioxide
represented 79.4 percent of total emissions, and the largest source of GHG emissions was
fossil fuel combustion from transportation (e.g., passenger vehicles, freight trucks, light-duty
trucks), followed by fossil fuel electric power generation (EPA 2023b). In 2021, the total amount
of CO2eq emissions related to fossil fuel electricity generation was 1,698.6 million tons
(1,540.0 million MT) (EPA 2023b). Table 3.12-1 presents annual GHG emissions by State.
Table 3.12-1 Greenhouse Gas Emissions by State, 2021
State
Alabama
Arkansas
Arizona
California
Colorado
Connecticut

Total GHG Emissions (tons)
78,647,020
39,911,994
42,302,602
102,281,112
68,786,547
11,358,835

21

Carbon dioxide equivalent (CO2eq) is a metric used to compare the emissions of GHGs based on their
global warming potential—a measure used to compare how much heat a GHG traps in the atmosphere.
The global warming potential is the total energy that a gas absorbs over a period of time, compared to
CO2. CO2eq is obtained by multiplying the amount of the GHG by the associated GWP. For example, the
global warming potential of CH4 is estimated to be 21; therefore, one ton of CH4 emission is equivalent to
21 tons of CO2 emission.

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State
District of Columbia
Delaware
Florida
Georgia
Iowa
Idaho
Illinois
Indiana
Kansas
Kentucky
Louisiana
Massachusetts
Maryland
Maine
Michigan
Minnesota
Missouri
Mississippi
Montana
North Carolina
North Dakota
Nebraska
New Hampshire
New Jersey
New Mexico
Nevada
New York
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennessee
Texas
Utah
Virginia
Vermont
Washington
West Virginia
Wisconsin
Wyoming

Total GHG Emissions (tons)
228,780
6,062,395
117,442,818
57,129,721
47,759,886
5,228,328
86,749,926
121,063,006
34,662,502
73,851,815
141,966,414
9,775,294
18,571,950
3,325,184
75,973,001
38,258,154
73,367,937
40,007,199
17,010,471
50,031,912
40,223,525
26,997,794
2,727,081
20,495,290
29,099,867
17,304,926
37,715,304
109,824,524
71,380,092
13,012,892
118,746,193
3,774,992
35,048,121
5,614,865
39,438,082
465,575,617
38,617,337
39,556,219
446,169
22,005,840
77,068,739
44,532,140
52,212,301

GHG = greenhouse gas.
To convert to metric tons (MT) multiply by 0.907.
Source: EPA 2023c.

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The 2013 LR GEIS presents life-cycle GHG emissions associated with nuclear power
generation. The nuclear life-cycle GHG emissions consists of the uranium fuel cycle phases,
and nuclear power plant construction, operation, and decommissioning. As presented in
Table 4.12-4 through Table 4.12-6 of the 2013 LR GEIS, life-cycle GHG emissions from power
generation can range from 1 to 228 grams carbon equivalent per kilowatt-hour. GHG emissions
from operation of nuclear power plants are typically very minor because such plants, by their
very nature, do not normally burn fossil fuels to generate electricity. Sources include stationary
and mobile combustion sources, including diesel generators, pumps, diesel engines, boilers,
worker vehicles, or delivery vehicles. Other GHG sources from nuclear power plants may
include human-made fluorinated compounds. These include hydrofluorocarbons and
perfluorocarbons contained in refrigerants. Sulfur hexafluoride is used in electric power
transmission and distribution applications and can be found in substations, circuit breakers, and
other switchgear. Sulfur hexafluoride gas has replaced flammable insulating oils in many
applications and allows for more compact substations. Fugitive emissions of sulfur hexafluoride
can escape from gas-insulated substations and switchgear through seals, especially those in
older equipment. The gas can also be released during equipment manufacturing, installation,
servicing, and disposal (EPA 2023b).
Operations at nuclear power plants release GHGs (primarily CO2) from stationary combustion
sources (e.g., diesel generators, pumps, diesel engines, boilers), refrigeration systems,
electrical transmission and distribution systems, and mobile sources (e.g., worker vehicles and
delivery vehicles). GHG emissions generated can be categorized into direct and indirect
emissions. The EPA has developed guidance to identify and scope sources to delineate,
inventory, and account for GHG emissions. Direct GHG emissions include those that are owned
or controlled by an organization (EPA 2022i). The EPA categorizes direct GHG emissions as
Scope 1 emissions. This includes GHG emissions associated with stationary and mobile
combustion sources at nuclear power plants, as well as fugitive emissions from refrigeration
equipment and transmission lines. Indirect emissions are those associated with an
organization’s activities but are emitted from sources owned by other entities. The EPA’s
guidance categorizes indirect GHG emissions as Scope 2 and Scope 3 emissions. Scope 2
GHG emissions include emissions associated with the purchase of electricity consumed by the
organization (EPA 2020b). Scope 3 emissions includes those from upstream and downstream
activities such as transportation of purchased products, employee commuting, and end of-life
treatment of sold products (EPA 2023f).
In 2009, the Commission issued a memorandum and order in CLI-09-21 (NRC 2009d) that
stated the following:
[B]ecause the Staff is currently addressing the emerging issues surrounding
greenhouse gas emissions in environmental reviews required for the
licensing of nuclear facilities, we believe it is prudent to provide the following
guidance to the Staff. We expect the Staff to include consideration of carbon
dioxide and other greenhouse gas emissions in its environmental reviews for
major licensing actions under the National Environmental Policy Act.
Following the issuance of CLI-09-21 (NRC 2009d), the NRC began to evaluate the effects of
GHG emissions and its implications for global climate change in its environmental reviews for
license renewal applications. For the 2013 LR GEIS, direct GHG emissions data for facilities
were not available to support an impact level determination for the license renewal term. Since
publication of the 2013 LR GEIS, the NRC has included within each SEIS a plant-specific
analysis of GHG emissions over the course of the license renewal term (initial and subsequent).

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Table 3.12-2 presents direct and indirect GHG emissions from representative operating nuclear
power plants. The observed range and distribution of direct and indirect GHG emissions from
site to site is a result of different sources and contributors, as well as differences in nuclear
power plant licensee GHG inventories. Not all States have GHG emission reporting
requirements, and EPA requires reporting only if the 25,000 MT threshold is met. In the absence
of these reporting requirements, nuclear power plant licensees do not inventory GHG data
uniformly.
Table 3.12-2 Estimated Greenhouse Gas Emissions from Operations at Nuclear Power
Plants
Nuclear Power Plant
Braidwood(b)
Byron(b)
Callaway(c)
Columbia(d)
Davis-Besse(e)
Fermi(f)
Indian Point(g)
LaSalle(h)
North Anna(i)
Peach Bottom(j)
Point Beach(k)
River Bend(l)
Seabrook(m)
Surry(n)
Turkey Point(o)
Waterford(p)

Direct Greenhouse Gas
Emissions (T/yr)(a)

Indirect Greenhouse Gas
Emissions (T/yr)(a)

3,562–14,778
4,761–7,638
845–5,042
650–856
5,173
6,411–11,897
540–7,188
2,500
430–690
29,705
660–1,110
360–820
7,893–47,778
340–4,630
500–790
716–3,087

16,459–24,380
6,307–7,638
N/A
N/A
N/A
4,166
4,928
36,066
4,490
10,090
3,460
2,900
N/A
4,730
3,400
3,307

N/A = not available; T/yr = ton per year.
(a) To convert to metric tons (MT) multiply by 0.907.
(b) Data available for 2008–2012. Direct emissions include onsite combustion sources, refrigerants, and the CO 2
purge and fire protection system. Indirect emissions are from purchased electricity. Sources: NRC 2015c,
NRC 2015d, Exelon Generation Company 2013, Exelon Generation Company 2014.
(c) Data available for 2007–2011. Direct emissions include onsite combustion sources. Source: NRC 2014f.
(d) Data available for 2006–2009. Direct emissions include onsite combustion sources. Source: NRC 2012a.
(e) Data available for 2010. Direct emissions include onsite combustion sources. Source: NRC 2015e.
(f) Data available for 2009–2013. Direct emissions include onsite combustion sources and refrigerants. Indirect
emissions source include worker vehicles. Source: NRC 2016c.
(g) Data available for 2009–2013. Direct emissions include onsite combustion sources and electrical equipment
related sources. Indirect emissions include worker vehicles. Source: NRC 2018e.
(h) Data available for 2010–2014. Direct emissions include onsite combustion sources, refrigerants, and fugitive
emissions sources (from the CO2 injection system, fire protection system, and condensers). Indirect emissions
include purchased electricity. Source: NRC 2016d.
(i) Data available for 2013–2017. Direct emissions include onsite combustion sources. Indirect emissions from
worker vehicles. Source: NRC 2021g.
(j) Direct emissions include onsite combustion sources. Direct emissions are based on maximum allowable fuel
usage and hours as prescribed in Peach Bottom’s air permit, rather than actual fuel usage and run time.
Therefore, the emissions are overestimates. Indirect emissions include worker vehicles. Source: NRC 2020g.
(k) Data available for 2014–2018. Direct emissions include onsite combustion sources. Indirect emissions from
worker vehicles. Source: NRC 2021f.
(l) Data available for 2011–2015. Direct emissions include onsite combustion sources. Indirect emissions from
worker vehicles. Source: NRC 2018c.

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(m) Data available for 2005–2009. Direct emissions include onsite combustion sources and transmission substation.
In 2007, higher than normal GHG emissions resulted from two equipment failures that contributed to 42,479 tons
of CO2eq (of the total 47, 778 total direct emissions). Sources: NRC 2015b and NextEra Energy 2010.
(n) Data available for 2011–2015. Direct emissions include onsite combustion sources. Indirect emissions from
worker vehicles. Source: NRC 2020m.
(o) Data available for 2012–2016. Direct emissions include onsite combustion sources. Indirect emissions from
worker vehicles. Source: NRC 2019c.
(p) Data available for 2010–2014. Direct emissions include onsite combustion sources. Indirect emissions from
worker vehicles. Source: NRC 2018d.

3.12.2 Observed Changes in Climate
Climate change is the decades or longer change in climate measurements (e.g., temperature
and precipitation) that has been observed on a global, national, and regional level (IPCC 2007;
EPA 2016; USGCRP 2014). Climate change research indicates that the cause of the Earth’s
warming over the last 50 to 100 years is due to the buildup of GHGs in the atmosphere resulting
from human activities (IPCC 2013, IPCC 2021, IPCC 2023; USGCRP 2014, USGCRP 2017,
USGCRP 2018). Global surface temperature has increased faster since 1970 than in any other
50-year period over at least the last 2,000 years (IPCC 2023). On a global level, from 1901 to
2016, the average temperature has increased by 1.8°F (1.0°C) (USGCRP 2018). Since 1901,
precipitation has increased at an average rate of 0.04 in. (0.10 cm) per decade on a global level
(EPA 2023d). The observed global change in average surface temperature and precipitation
has been accompanied by an increase in sea surface temperatures, a decrease in global glacier
ice, an increase in sea level, and changes in extreme weather events. Such extreme events
include an increase in the frequency of heat waves, very heavy precipitation (defined as the
heaviest 1 percent of all daily events), and recorded maximum daily high temperatures (IPCC
2007; EPA 2016; USGCRP 2009, USGCRP 2014). From 1880 to 2013, the global average sea
level has risen at a rate of 0.06 in (0.15 cm) per year and from 1880 to 2020 global sea surface
temperature has increased at a rate of 0.14°F (0.07°C) per decade (EPA 2023d).
The 2013 LR GEIS summarized the findings of the Second Annual Climate Assessment
developed by the U.S. Global Change Research Program (USGCRP) (USGCRP 2009). The
USGCRP is a Federal program mandated by Congress to coordinate Federal research
conducted to better understand climate change. Since publication of the 2013 LR GEIS, Third
and Fourth Annual Climate Assessments have been published (USGCRP 2014 and USGCRP
2018). The Fourth Annual Climate Assessment (USGCRP 2018) builds on the work of the
previous assessments. The NRC uses consensus information, representing the best available
science and data, from the USGCRP to evaluate the effects of climate change in its SEISs for
license renewal of nuclear power plants. The USGCRP reports that from 1901 to 2016,
average surface temperatures have increased by 1.8°F (1.0°C) across the contiguous United
States (USGCRP 2018). Since 1901, average annual precipitation has increased by 4 percent
across the United States (USGCRP 2018). Observed climate change indicators across the
United States include increases in the frequency and intensity of heavy precipitation, earlier
onset of spring snowmelt and runoff, rise of sea level and increased tidal flooding in coastal
areas, an increased occurrence of heat waves, and a decrease in the occurrence of cold
waves. Since the 1980s, data show an increase in the length of the frost-free season (i.e., the
period between the last occurrence of 32°F [0°C] in the spring and first occurrence of 32°F
[0°C] in the fall), across the contiguous United States. Over the period 1991 through
2011, the average frost-free season was 10 days longer (relative to the 1901 through
1960 time period) (USGCRP 2014). Over just the past two decades, the number of
high-temperature records observed in the United States has far exceeded the number of

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low-temperature records (USGCRP 2018). Since the 1980s, the intensity, frequency, and
duration of North Atlantic hurricanes have increased (USGCRP 2014).
Climate change and its impacts can vary regionally, spatially, and seasonally, depending on
local, regional, and global factors. Observed climate changes and impacts have not been
uniform across the United States. For instance, annual precipitation has increased across most
of the northern and eastern States and decreased across the southern and western States. Sea
level rise and coastal flooding have not been evenly distributed. Along the Atlantic coast, the
U.S. Northeast has experienced a faster-than-global increase in sea level rise since the 1970s
(USGCRP 2017). To provide localized information and greater granularity, USGCRP’s Annual
Climate Assessments (USGCRP 2014, USGCRP 2018) describe observed and projected
changes in climate by U.S. geographic regions: Northeast, Southeast, Caribbean, Midwest,
Northern Great Plains, Southern Great Plains, Northwest, Southwest, Midwest, Alaska, and
Hawaii and U.S. Pacific Islands (see Figure 3.12-1). As shown in Figure 3.12-1, U.S. operating
nuclear power plants are primarily located in the Northeast, Southeast, and Midwest regions.
Section G.12.1 in Appendix G of this LR GEIS provides a summary of the observed climate
changes by the contiguous U.S. region, with a focus on regions where operating nuclear power
plants are located.

Figure 3.12-1 Locations of Operating Nuclear Power Plants Relative to National Climate
Assessment Geographic Regions

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ENVIRONMENTAL CONSEQUENCES AND MITIGATING ACTIONS

The U.S. Nuclear Regulatory Commission (NRC) evaluated the environmental consequences of
the proposed action (i.e., license renewal) including the (1) impacts of continued reactor
operations and refurbishment activities associated with initial license renewal (initial LR) and
one term of subsequent license renewal (SLR); (2) impacts of various reasonable alternatives to
the proposed action (see Appendix D); (3) impacts from the termination of nuclear power plant
operations and decommissioning after the license renewal term (with emphasis on the
incremental effect caused by an additional 20 years of subsequent operation); (4) impacts
associated with the uranium fuel cycle; (5) impacts of postulated accidents (design-basis
accidents and severe accidents); (6) cumulative impacts of the proposed action; and
(7) resource commitments associated with the proposed action, including unavoidable adverse
impacts, the relationship between short-term use and long-term productivity, and irreversible
and irretrievable commitment of resources.
Contents of Chapter 4
• Environmental Consequences and Mitigating Actions (Section 4.1)
• Land Use and Visual Resources (Section 4.2)
• Air Quality and Noise (Section 4.3)
• Geologic Environment (Section 4.4)
• Water Resources (Section 4.5)
• Ecological Resources (Section 4.6)
• Historic and Cultural Resources (Section 4.7)
• Socioeconomics (Section 4.8)
• Human Health (Section 4.9)
• Environmental Justice (Section 4.10)
• Waste Management and Pollution Prevention (Section 4.11)
• Greenhouse Gas Emissions and Climate Change (Section 4.12)
• Cumulative Effects of the Proposed Action (Section 4.13)
• Impacts Common to All Alternatives (Section 4.14)
• Resource Commitments Associated with the Proposed Action (Section 4.15)

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4.1
4.1.1

Environmental Consequences and Mitigating Actions
Introduction

When considering whether the environmental effects (impacts) of the proposed action are
significant, the NRC analyzes the relevant geographic area and intensity of the effects of the
proposed action (initial LR or SLR). The NRC has established three significance levels—
SMALL, MODERATE, and LARGE—and uses these levels in nuclear power plant-specific
(hereafter called plant-specific) supplemental environmental impact statements (SEISs) to the
Generic Environmental Impact Statement for License Renewal of Nuclear Plants (referred to in
this document as the LR GEIS). As explained in Section 1.5.2.3, the three significance levels
are defined as follows:
• SMALL: Environmental effects are not detectable or are so minor that they will neither
destabilize nor noticeably alter any important attribute of the resource. For the purposes of
assessing radiological impacts, the Commission has concluded that those impacts that do not
exceed permissible levels in the Commission’s regulations are considered SMALL.
• MODERATE: Environmental effects are sufficient to alter noticeably, but not to destabilize,
important attributes of the resource.
• LARGE: Environmental effects are clearly noticeable and are sufficient to destabilize
important attributes of the resource.
These levels are used for describing the environmental impacts of the proposed action in this
chapter as well as the impacts of a range of reasonable alternatives to the proposed action (see
Appendix D). Resource-specific effects or impact definitions from applicable environmental laws
and executive orders, other than SMALL, MODERATE, and LARGE, are provided where
appropriate. In this LR GEIS, the NRC’s environmental impact levels are informed by Council on
Environmental Quality (CEQ) terminology and guidance including revisions in Part 1501—NEPA
and Agency Planning (see Title 40 Part 1501 of the Code of Federal Regulations [40 CFR
Part 1501]) and Part 1508—Definitions (40 CFR Part 1508; 89 FR 35442).
4.1.2

Environmental Consequences of the Proposed Action

As described in Section 2.1, activities associated with the proposed action could have
environmental consequences at a nuclear power plant site. The proposed action includes
activities associated with the normal operation of a nuclear power plant during the license
renewal (initial LR or SLR) term, including (1) reactor operations; (2) surveillance, monitoring,
and maintenance activities related to systems, structures, and components within the scope of
license renewal; (3) waste management; (4) refueling and other outages; (5) activities needed to
support facility infrastructure requirements as part of routine operations and maintenance
(e.g., road improvements and the installation or construction of new structures and other
support facilities); and (6) any refurbishment activities needed to replace and/or repair critical
portions of reactor systems for the purposes of license renewal.
The assessment includes a determination of the magnitude of the impact (SMALL,
MODERATE, or LARGE) and whether the analysis of the environmental issue could be applied
to all or a subset of nuclear plants, and whether plant-specific mitigation measures would be
warranted. Environmental issues are assigned a Category 1 (generic) or a Category 2
(plant-specific) designation, as described in Section 1.5.2.3.

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A total of 80 environmental issues (i.e., 59 Category 1, 20 Category 2, and 1 uncategorized)
related to the proposed action were identified (summarized in Table 2.1-1). For each potential
environmental issue identified, the NRC (1) describes the nuclear power plant activity during the
initial LR or SLR term that could affect the resource, (2) identifies environmental resources that
may be affected, (3) evaluates past license renewal reviews and other available information,
including information related to impacts during a SLR term, (4) assesses the nature and
magnitude of the environmental impact on the affected resource, (5) characterizes the
significance of the effect, (6) determines whether the results of the analysis apply to all or a
subset of nuclear power plants (i.e., whether the impact issue is Category 1 or Category 2), and
(7) describes mitigation measures for adverse impacts.
4.1.3

Environmental Consequences of Continued Operations and Refurbishment
Activities During the License Renewal Term (Initial or Subsequent)

Activities occurring during the initial LR or SLR term are the subject of this evaluation and are
described in Section 2.1. This chapter presents the NRC’s analysis of the incremental
environmental effects (impacts) of renewing the operating licenses of commercial nuclear power
plants for an additional 20 years beyond the current license term to provide an option that allows
for baseload power generation capability beyond the term of the current nuclear power plant
operating license to meet future system generating needs. The environmental impacts during
the construction of a nuclear power plant and past operational impacts are not the focus of this
evaluation. Construction impacts and the impacts of past operations have affected and, in many
cases, shaped current environmental conditions at each nuclear plant and in its surroundings.
These environmental conditions serve as the baseline for the impact analyses of continued
operations and refurbishment activities during the license renewal term. Past environmental
impacts are addressed in Chapter 3, Affected Environment. The impacts of continued
operations and any refurbishment activities during the initial LR or SLR term are the same or
similar to the impacts already occurring during the current license term. In most cases, impacts
would remain the same and are SMALL. This is because initial LR or SLR would continue
current operating conditions and environmental stressors rather than introduce wholly new
impacts. In other cases, impacts could change and may be MODERATE or LARGE. Further, in
reviewing and updating the 2013 LR GEIS to account for SLR, the NRC also considered
whether any feature of the analysis in the 2013 LR GEIS would be incompatible with SLR.
The NRC staff’s review considered lessons learned, knowledge gained, and new information
identified from license renewal environmental reviews performed since development of the
2013 LR GEIS (NRC 2013a). The environmental reviews included initial LR for the following
15 nuclear power plants: Seabrook Station (Seabrook; NRC 2015b), Columbia Generating
Station (Columbia; NRC 2012a), South Texas Project Electric Generating Station (South Texas;
NRC 2013b), Limerick Generating Station (Limerick; NRC 2014d), Grand Gulf Nuclear Station
(Grand Gulf; NRC 2014e), Callaway Plant (Callaway; NRC 2014f), Davis-Besse Nuclear Power
Station (Davis-Besse; NRC 2015e), Sequoyah Nuclear Plant (Sequoyah; NRC 2015f), Byron
Station (Byron; NRC 2015c), Braidwood Station (Braidwood; NRC 2015d), Enrico Fermi Atomic
Power Plant (Fermi; NRC 2016c), LaSalle County Station (LaSalle; NRC 2016d), Indian Point
Energy Center (Indian Point; NRC 2018e), River Bend Station (River Bend; NRC 2018c), and
Waterford Steam Electric Station (Waterford; NRC 2018d).

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Additionally, the staff considered the results from SLR environmental reviews for the following
5 nuclear power plants: Turkey Point Nuclear Plant (Turkey Point; NRC 2019c), Peach Bottom
Atomic Power Station (Peach Bottom; NRC 2020g), Surry Power Station (Surry; NRC 2020f),
North Anna Power Station (North Anna; NRC 2021g), and Point Beach Nuclear Plant (Point
Beach; NRC 2021f).
The NRC staff also considered new scientific research, public comments, changes in
environmental regulations and impacts methodology, and other new information in evaluating
the impacts associated with license renewal (initial LR or SLR).
Based on the NRC staff’s review, a total of 80 environmental issues for the initial LR or SLR of
nuclear power plants were identified and evaluated; they are summarized in Table 2.1-1. This
revised LR GEIS provides the technical basis for the summary of findings on environmental
issues in Table B-1 in Appendix B, Subpart A, of 10 CFR Part 51. The identified issues are
discussed by resource area in this chapter. The assessment approaches specific to each
resource area are described in Appendix G.
4.1.4

Environmental Consequences of the No Action Alternative

The no action alternative (see Section 2.2) represents a decision where the NRC does not issue
a renewed operating license. The licensee would then have to terminate reactor operations at
the end of its current license and permanently shut down the nuclear power plant. At some
point, all licensees will terminate nuclear plant operations and undergo decommissioning. Under
the no action alternative, this would occur sooner than it would if the NRC issued a renewed
operating license.
Not renewing the operating license and ceasing nuclear plant operation under the no action
alternative would lead to a variety of potential outcomes. These outcomes would be the same
as those that would occur after license renewal (see Section 4.14.2 for a discussion of these
effects). Termination of reactor operations would result in a net reduction in power generating
capacity. Power not generated by the nuclear plant during license renewal would likely be
replaced by (1) replacement energy alternatives, (2) energy conservation and efficiency
(demand-side management), (3) delayed retirements, (4) purchased power, or (5) some
combination of these options, as evaluated in Appendix D. The consideration of the no action
alternative does not involve the determination of whether replacement energy is needed or
should be generated. The decision to generate electric power and the determination of how
much power is needed are at the discretion of State, Federal (non-NRC), and utility officials.
4.1.5

Environmental Consequences of Alternative Energy Sources

Section 2.4 of this LR GEIS summarizes the potential environmental impacts from the
construction and operation of alternative energy technologies (including fossil fuel, new nuclear,
and renewable energy) to replace the amount of electric power generated by an existing nuclear
power plant. Appendix D presents the NRC’s detailed consideration and analysis of potential
alternative energy sources and their impacts as compared to the proposed action (license
renewal), which will inform the SEIS prepared for plant-specific license renewals.

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4.1.6

Environmental Consequences of Terminating Nuclear Power Plant Operations
and Decommissioning

All operating nuclear power plants will terminate operations and begin decommissioning either
at the end of their operating license or after a decision is made to cease reactor operations.
License renewal would delay this eventuality for up to an additional 20 years beyond the
current operating license period. The environmental impacts of decommissioning nuclear power
plants were evaluated in NUREG-0586, Generic Environmental Impact Statement on
Decommissioning of Nuclear Facilities, Supplement 1: Regarding the Decommissioning of
Nuclear Power Reactors (Decommissioning GEIS; NRC 2002c). The effects of renewing an
operating license on the eventual impacts of terminating a nuclear power reactor license and the
ensuing decommissioning are addressed as a single environmental issue. Because the impacts
of license renewal on terminating plant operations and decommissioning are expected to be
SMALL at all nuclear plants and for all environmental resources, it is considered a Category 1
issue. These impacts are discussed in Section 4.14.2.

4.2

Land Use and Visual Resources

4.2.1

Environmental Consequences of the Proposed Action – Continued Operations
and Refurbishment Activities

Industrial land use at nuclear plants is not expected to change appreciably until after
decommissioning is completed. Similarly, land use activity within transmission line right-of-ways
(ROWs) would continue with few, if any, changes in land use restrictions and easements.
In addition, the visual appearance of nuclear power plants and transmission lines have been
well established. These conditions are expected to remain unchanged during the initial LR or
SLR term regardless of the prior number of years of nuclear plant operation.
4.2.1.1

Land Use

Environmental reviews have shown that license renewal and refurbishment have had little or no
effect on land use at or near nuclear power plants. Land use impact issues evaluated in this
LR GEIS revision include the impacts of continued plant operations and refurbishment activities
on (1) onsite land use, (2) offsite land use, and (3) offsite land use in transmission line ROWs.
4.2.1.1.1

Onsite Land Use

Operational activities during both the initial LR or SLR term would be similar to those already
occurring at the nuclear plant. The industrial nature of onsite land use would remain unchanged.
However, additional spent nuclear fuel and low-level radioactive waste would be generated
during the license renewal term. This could require the construction of new or the expansion of
existing onsite storage facilities. Future expanded installations would likely be located adjacent
to existing storage facilities or otherwise in existing industrialized areas of the plant sites. This
action would be addressed in separate environmental reviews. The NRC has not identified any
information or situations during license renewal environmental reviews that would alter the
conclusion that land use impacts from continued plant operations and refurbishment would be
SMALL for all nuclear plants. Refurbishment activities, such as steam generator and vessel
head replacement, have not permanently altered onsite land use.

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Based on these considerations, the NRC concludes that impacts from continued nuclear plant
operations during the initial LR and SLR terms and refurbishment on onsite land use would be
the same—SMALL for all nuclear plants. The staff reviewed information from SEISs (for
initial LRs and SLRs) completed since development of the 2013 LR GEIS and identified no new
information or situations that would result in different impacts for this issue for either an initial LR
or SLR term. Therefore, onsite land use impacts would be SMALL for all nuclear plants, and it is
a Category 1 issue.
4.2.1.1.2

Offsite Land Use

Environmental reviews have shown that initial LR or SLR and refurbishment activities have had
little to no direct effect on development trends near nuclear power plants, including changes in
population or tax revenue in communities near nuclear power plants. Employment levels at
nuclear plants remain the same or have decreased with no increased demand for housing,
infrastructure improvements, or services. Operational activities during the license renewal term
would be similar to those already occurring at the nuclear plant and would not affect offsite land
use beyond what has already been affected. The NRC has not identified any information or
situations, including in low-population areas or population and tax revenue changes resulting
from initial LR or SLR, that would alter the conclusion that impacts on offsite land use would be
SMALL for all nuclear power plants.
For nuclear plants located in a coastal zone or coastal watershed, as defined by each State
participating in the National Coastal Zone Management Program, applicants must submit to the
affected State a certification that the proposed license renewal action is consistent with the
State Coastal Zone Management Program. Applicants must receive a determination from the
State agency that manages the State Coastal Zone Management Program that the proposed
license renewal action would be consistent with the State program. Consistency with State
Coastal Zone Management Programs further demonstrates that impacts in State coastal zones
will be small.
Based on these considerations, the NRC concludes that impacts from continued nuclear plant
operations during the initial LR and SLR terms and refurbishment on offsite land use would be
the same—SMALL for all nuclear plants. The staff reviewed information from SEISs (for
initial LRs and SLRs) completed since development of the 2013 LR GEIS and identified no new
information or situations that would result in different impacts for this issue either for an initial LR
or SLR term. Therefore, offsite land use impacts would be SMALL for all nuclear plants, and it is
a Category 1 issue.
4.2.1.1.3

Offsite Land Use in Transmission Line Right-of-Ways

Transmission lines that connect the nuclear plant to the switchyard where electricity is fed into
the regional power distribution system (the first substation of the regional electric power grid)
and lines that feed electricity to the nuclear plant from the grid during outages are within the
scope of license renewal environmental reviews. Operational activities in transmission line
ROWs during the initial LR or SLR term would be the same or similar to those already occurring
and would not affect offsite land use beyond what has already been affected.
Transmission lines do not preclude the use of the land in ROWs for other purposes, such as
agriculture and recreation. Transmission lines connecting nuclear plants to the electrical grid are
no different from transmission lines connecting any other power plant to the grid. However,
certain land use activities in transmission line ROWs are restricted. Land cover is generally

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Environmental Consequences and Mitigating Actions
managed through a variety of maintenance procedures so that vegetation growth and building
construction do not interfere with transmission line operation and access. Consequently, land
use within transmission line ROWs is limited to activities that do not endanger power line
operation; these activities include recreation, off-road vehicle use, grazing, agriculture, irrigation,
roads, environmental conservation, and use as wildlife areas.
The impact of transmission lines on offsite land use during the license renewal term is
considered to be SMALL for all nuclear plants and a Category 1 issue in the 2013 LR GEIS.
The staff reviewed information from SEISs (for initial LRs and SLRs) completed since
development of the 2013 LR GEIS and identified no new information or situations that would
result in different impacts for this issue for either an initial LR or SLR term. Therefore, impacts in
offsite land use in transmission line ROWs would be SMALL for all nuclear plants, and it is a
Category 1 issue.
4.2.1.2

Visual Resources

License renewal environmental reviews have shown that nuclear power plants and transmission
lines do not change in appearance over time, so aesthetic impacts are not anticipated during the
initial LR or SLR term.
4.2.1.2.1

Aesthetic Impacts

The NRC considered the visual impact of continued nuclear plant operations and refurbishment
during the license renewal term in the 2013 LR GEIS. The NRC concluded aesthetic impacts
would be SMALL for all nuclear plants and a Category 1 issue, because the visual appearance
of nuclear power plants and transmission lines are not expected to change during the license
renewal term.
Separately, a case study found a limited number of situations where nuclear power plants have
had a negative effect on the public (NRC 1996). Negative perceptions were based on aesthetic
considerations (for instance, the nuclear plant is out of character or scale with the community
or the viewshed), physical environmental concerns, safety and perceived risk issues, an
ant-nuclear plant attitude, or an anti-nuclear outlook. It is believed that these negative
perceptions would persist regardless of any mitigation. Subsequently, license renewal
environmental reviews have not revealed any new information that would change this
perception.
After cooling towers and the containment building, transmission line towers are probably the
most frequently observed structure associated with nuclear power plants. Transmission lines
from nuclear plants are generally indistinguishable from those from other power plants. Because
electrical transmission lines are common throughout the United States, they are generally
perceived with less prejudice than the nuclear power plant itself. Also, the visual impact of
transmission lines tends to wear off when viewed repeatedly. Replacing or moving towers or
burying cables to reduce the visual impact would be impractical from both a cost and efficiency
perspective. The visual impact of transmission lines during the license renewal term was also
considered to be SMALL for all nuclear plants and a Category 1 issue in the 2013 LR GEIS. No
new information or situations that would alter that conclusion has been identified in initial LR or
SLR environmental reviews.

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Based on these considerations, the NRC concludes the aesthetic impact of continued nuclear
plant operations during initial LR and SLR terms and refurbishment would be the same—SMALL
for all nuclear plants. The staff reviewed information from SEISs (for initial LRs and SLRs)
completed since development of the 2013 LR GEIS and identified no new information or
situations that would result in different impacts for this issue for either an initial LR or SLR term.
The visual appearance of nuclear plants would not change or have a different level of impact.
Therefore, aesthetic impacts would be SMALL for all nuclear plants, and it is a Category 1
issue.

4.3

Air Quality and Noise

4.3.1

Environmental Consequences of the Proposed Action – Continued Operations
and Refurbishment Activities

Ambient air quality and noise conditions at all nuclear power plants and associated transmission
lines have been well established during the current licensing term. These conditions are
expected to remain unchanged during the license renewal term (initial LR or SLR term).
This section focuses on the impacts of continued operations and refurbishment activities
associated with license renewal on air quality and noise. Refurbishment and associated
construction activities can affect air quality (e.g., fugitive dust, vehicle and equipment exhaust
emissions, and automobile exhaust from commuter traffic). Baseline meteorological,
climatological, and ambient air quality and noise conditions at operating plants are discussed in
Sections 3.3.1, 3.3.2, and 3.3.3, respectively. License renewal is expected to result in a
continuation of similar conditions for an extended period commensurate with the license renewal
term (initial LR or SLR term). As a result, the criteria air pollutants emitted and the noise
generated during normal continued nuclear plant operations during the initial LR or SLR term
are not expected to change substantially and thus should remain SMALL.
4.3.1.1

Air Quality

Two issues related to impacts on air quality during the license renewal (initial LR or SLR) terms
are considered in this section including (1) air quality impacts and (2) air quality effects of
transmission lines.
4.3.1.1.1

Air Quality Impacts

Impacts on air quality during normal plant operations can result from operations of fossil fuelfired equipment needed for various plant functions (see Section 3.3.2). Each licensed plant
typically employs emergency diesel generators for use as a backup power source. These
generators provide a standby source of electric power for essential equipment required during
plant upset or an emergency event. They also provide for safe reactor shutdown and for the
maintenance of safe conditions at the power station during such an event. These diesel
generators are typically tested once a month with several test burns of various durations
(e.g., 1 to several hours). In addition to these maintenance tests, longer-running endurance
tests are also typically conducted at each plant. Each generator is typically tested for 24 hours
on a staggered test schedule (e.g., once every refueling outage). Plants with nonelectric fire
pumps, typically also diesel-fired, usually employ test protocols identical or similar to those used
for emergency generators. Maintenance procedures during these tests would include, for
example, checks for leaks of lubricating oil or fuel from equipment, and pumps would be
replaced as required.

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In addition to the emergency diesel generators, fossil fuel (i.e., diesel-, oil-, or natural gas-fired)
boilers are used primarily for evaporator heating, plant space heating, and/or feed water
purification. These units typically operate at a variable load on a continuous basis throughout
the year unless end use is restricted to one application, such as space heating. For example,
the Peach Bottom plant uses two auxiliary boilers for space heating and to help with unit
startups (NRC 2020g). Air emissions include carbon monoxide (CO), nitrogen oxides (NOx),
carbon dioxide (CO2), methane, nitrous oxide, particulate matter (PM), and volatile organic
compounds (VOCs) for diesel-, natural gas-, and oil-fired units. Natural gas-fired units emit only
trace amounts of VOCs and PM that has an aerodynamic diameter of 10 m or less (PM10). The
utility boilers at commercial plants are relatively small compared to most industrial boilers and
are typically regulated through State-level operating permits.
Given the infrequency and short duration of maintenance testing of onsite combustion sources,
annual air emissions are minor. For example, the contribution of air emissions from sources at
the LaSalle, River Bend, Waterford, Peach Bottom, Turkey Point, Surry, Point Beach, and
North Anna plants constitute anywhere from 0.2 to 2 percent of the County’s (where the plant is
located) annual air emissions (NRC 2016d, NRC 2018c, NRC 2018d, NRC 2020g, NRC 2019c,
NRC 2020f, NRC 2021f, NRC 2021g). Therefore, annual air emissions from nuclear power plant
sources would not be an air quality concern even at those plants located in or adjacent to
nonattainment areas. The locations of the currently designated nonattainment areas near
nuclear plants are shown in Section 3.3.2.
As discussed in Section 3.3.2, cooling tower drift can increase downwind PM concentrations,
impair visibility, ice roadways, cause drift deposition, and damage vegetation and painted
surfaces. Currently, 16 nuclear power plants use natural draft cooling towers, and 11 nuclear
power plants use mechanical draft cooling towers. Currently, no dry or hybrid (combinations
incorporating elements of both dry and wet design) systems are being used at operating nuclear
plants. The natural draft cooling tower at the Hope Creek Generating Station (Hope Creek) in
New Jersey is the only operating tower at a plant that uses high-salinity water for cooling system
makeup, which results in greater PM10 concentrations (NRC 2011b). An air quality impact
analysis performed in support of an extended power uprate request for Hope Creek assessed
emissions related to cooling tower drift droplets for this situation. The analysis determined that
cooling tower operations would result in average PM10 emissions of 35.6 pounds per hour
(lb/hr), as summarized in Section 3.3.2, and the New Jersey Department of Environmental
Protection determined that the PM10 emissions would not exceed National Ambient Air Quality
Standards. Thus, although there is the potential for some air quality impacts to occur as a result
of equipment and cooling tower operations, as in the case with Hope Creek, the impacts have
been small.
Diesel generators, pumps, fossil fuel boilers, and cooling towers typically require State or
local operating permits. Operating permits specify conditions that limit air emissions, hours
of operation, fuel content, or fuel consumption. Most State air pollution regulations provide
air permit exemptions for air pollution sources that are not routinely operated, which can be
defined as sources with insignificant activity meeting specified operating criteria (e.g., so
many hours of continuous operation over specified periods or so many hours of operation
per year). For example, the North Anna plant has one emergency generator, one diesel
generator, and two fire pump diesel generators that are exempt from the site’s State
Operating Permit conditions because they are considered insignificant equipment
emission units of minimal or no air quality concern (NRC 2021g). The Fermi plant uses
two natural draft hyperbolic cooling towers that are exempt from Michigan’s air permitting

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requirements. Particulate matter (with a diameter of 10 microns or less) emissions of each
cooling tower are estimated to be 0.10 tons per year (T/yr) (NRC 2016c).
License renewal environmental reviews performed since publication of the 2013 LR GEIS (see
Section 4.1.3) have not identified new information or situations that would result in air quality
impacts that would differ from what was concluded in the 2013 LR GEIS for either an initial LR
or SLR term. In the SEISs (for initial LRs and SLRs), the NRC concluded that fossil fuel-fired
equipment is operated intermittently, primarily during testing or outages, annual air emissions
are minor, and air emissions and sources would not be expected to change or have different
impacts on air quality during the LR term. Therefore, the potential impact from onsite air
emission sources on air quality would be expected to be SMALL for all nuclear plants, and it is a
Category 1 issue.
Potential sources of impacts on air quality during refurbishment activities associated with
continued operations during the license renewal term include (1) fugitive dust from site
excavation and grading and (2) emissions from motorized equipment, construction vehicles, and
workers’ vehicles. With application of adequate controls or mitigation measures and best
practices, the air quality impacts from these air pollution sources would be small and of
relatively short duration.
During site excavation and grading, some PM in the form of fugitive dust would be released into
the atmosphere. Construction vehicles and other motorized equipment would generate exhaust
emissions that include small amounts of CO, NOx, VOCs, and PM. These emissions would be
temporary (restricted to the construction period) and localized (occurring only in the immediate
vicinity of construction areas). For refurbishment occurring in geographical areas with poor or
marginal air quality, the emissions generated from these activities could be cause for concern in
a few cases (e.g., building demolition, debris removal, and new construction). However, the
1990 Clean Air Act Amendments include a provision that requires Federal actions conform to an
applicable State Implementation Plan designed to achieve the National Ambient Air Quality
Standards for criteria pollutants (sulfur dioxide [SO2], nitrogen dioxide, CO, ozone, lead, PM10,
and PM with a mean aerodynamic diameter of 2.5 m or less [PM2.5]).
On April 5, 2010, the U.S. Environmental Protection Agency (EPA) issued its 40 CFR Part 51
and 93 revisions to the General Conformity Regulations in the Federal Register (75 FR 17254).
General conformity requires Federal agencies to ensure that a proposed Federal action, such
as initial LR or SLR, in air quality nonattainment or maintenance areas conforms to the
applicable State Implementation Plan. A conformity analysis must be completed before the
action is taken. A conformity analysis begins with an applicability analysis to determine whether
the action is exempt or has total net direct and indirect emissions below the de minimis levels.
The de minimis emission levels (40 CFR 93.153(b)) serve as screening values to determine
whether a conformity determination must be undertaken for a proposed Federal action. The
applicability analysis must be documented. If conformity applies, the agency must prepare a
written conformity analysis and determination for each pollutant for which the emissions caused
by a proposed Federal action would exceed the de minimis levels. An area is designated as
nonattainment for a criteria pollutant if it does not meet National Ambient Air Quality Standards
for the pollutant. A maintenance area is one that a State has redesignated from nonattainment
to attainment. The current nationwide designations of nonattainment areas are identified in
Section 3.3.2.

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The de minimis levels for air emissions vary depending on air quality conditions in the area
where the plant is located. In most cases, the de minimis levels are established at 100 T/yr.
Exceptions include:
• NOx or VOC emissions of 10, 25, and 50 T/yr in extreme, severe, and serious ozone
nonattainment areas, respectively
• VOC emissions of 50 T/yr in ozone nonattainment areas inside an ozone transport region
stretching from Virginia to Maine
• Lead emissions of 25 T/yr in lead nonattainment areas
• PM10 emissions of 70 T/yr in serious PM10 nonattainment areas
• SO2, NOx, VOC, and ammonia emissions of 70 T/yr in serious PM2.5 nonattainment areas
In maintenance areas, the de minimis levels are 100 T/yr for all pollutants, except for 50 T/yr for
VOCs inside the ozone transport region and 25 T/yr for lead. If license renewal will result in an
increase in air emissions and the site is located in a designated nonattainment or maintenance
area, a conformity determination will be conducted by the NRC and documented in a
plant-specific SEIS.
The EPA regulations require that direct construction emissions including construction vehicle
and equipment exhaust and fugitive dust and indirect emissions, such as those from worker and
delivery vehicles, be included in the conformity analysis. Emissions from construction equipment
and vehicles are expected to be small for anticipated refurbishment projects based on activities
that have occurred to date. In the 1996 LR GEIS, the NRC concluded that the impacts from
plant refurbishment associated with license renewal on air quality could range from SMALL to
LARGE, although these impacts were expected to be SMALL for most plants. The
1996 LR GEIS determined that emissions from 2,300 vehicles over a 9-month refurbishment
period may exceed the thresholds for CO, NOx, and VOCs in nonattainment and maintenance
areas. In the 2013 LR GEIS, the NRC concluded that the impact of refurbishment activities on
air quality would be SMALL for most plants. The 2013 LR GEIS noted that findings from license
renewal SEISs published since the 1996 LR GEIS have shown that refurbishment activities,
such as steam generator and vessel head replacement, have not required the large numbers of
workers, months of time, or the degree of land disturbance that was conservatively estimated in
the 1996 LR GEIS. For example, refurbishment activities associated with the initial LR for
Davis-Besse required an additional 1,400 workers for 90 days. It was estimated that the
additional worker vehicles for this duration would result in 25 tons (T) of VOCs, 49 T of NOx,
1.0 T of SO2, and 1.5 T of PM2.5 (direct emissions) being emitted, which would not exceed the
de minimis levels of 100 T/yr of NOx, 50 T/yr of VOCs for ozone maintenance areas, 100 T/yr of
direct emissions of PM2.5, 100 T/yr of SO2, 100 T/yr for PM2.5 maintenance areas and 100 T/yr
for SO2 nonattainment areas, as set forth in 40 CFR 93.153(b) (NRC 2015e). Additionally,
Exelon Generating Company LLC (Exelon) estimated that steam generator replacement of
Byron Unit 2 would require an additional 500 workers for 90 days (NRC 2015c). The NRC staff
concluded that the additional workforce for steam generator replacement activities would be
temporary and estimated to result in an additional 3.3 T (3.0 metric tons [MT]) of VOCs,
9.8 T(8.9 MT) of NOx, 0.04 T (0.04 MT) of SO2, and 0.40 T (0.36 MT) of PM2.5 (direct emissions)
being emitted, which do not exceed the de minimis levels of 100 T/yr set forth in 40 CFR
93.153(b). Therefore, the NRC concluded that the additional emissions resulting from these
activities would be minor (NRC 2015c). For Indian Point vessel head replacement and control
rod mechanism replacement, the NRC staff estimated that an additional 500 workers for
60 days would result in an additional 3.4 T (3.1 MT) of VOCs, 31.1 T (28.2 MT) of CO, 2.3 T

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(2.1 MT) of NOx, 0.08 T (0.07 MT) of SO2, and 0.01 T (0.01 MT) of PM2.5 (NRC 2018e). These
additional emissions would not exceed the de minimis levels for designated maintenance areas
of 100 T (91 MT) for each pollutant.
The 1996 LR GEIS found that disturbed areas for refurbishment actions required 10 acres (ac)
(4 hectares [ha]) or less for laydown areas and storage. Since publication of the 1996 LR GEIS
and 2013 LR GEIS, the NRC has not identified refurbishment activities that would require
disturbance of land that exceeds 10 ac (4 ha). For example, as part of refurbishment activities
associated with initial LR for Davis-Besse, temporary and permanent buildings were constructed
and laydown areas were needed, which resulted in land disturbance of less than 10 ac (4 ha)
(NRC 2015e). For Indian Point vessel head replacement and control rod mechanism
replacement, storage would require construction of a permanent building requiring 0.12 ac
(0.04 ha) (NRC 2010a). Because of the (1) small size of the disturbed area, (2) relatively short
construction period, (3) availability of paved roadways at existing facilities, and (4) use of best
management practices (BMPs) (such as watering, chemical stabilization, and seeding), fugitive
dust resulting from these construction activities is minimal.
The staff reviewed information from SEISs (for initial LRs and SLRs) completed since
development of the 2013 LR GEIS and identified no new information or situations that would
result in different impacts for this issue for either an initial LR or SLR term. The NRC concludes
that the impact of refurbishment activities on air quality during the initial LR or SLR terms would
be SMALL. Impacts would be temporary and cease once projects were completed and
implementation of BMPs, including fugitive dust controls and the imposition of new and/or
revised conditions in State and local air emissions permits, would ensure conformance with
applicable State or Tribal implementation plans.
The NRC also concludes that the air quality impacts of continued nuclear plant operations
during the initial LR and SLR terms and refurbishment would be SMALL for all plants. The staff
has identified no information that would lead to different impacts on air quality during the
initial LR term or SLR term. Therefore, the impacts of initial LR and SLR on air quality is a
Category 1 issue.
4.3.1.1.2

Air Quality Effects of Transmission Lines

Small amounts of ozone and substantially smaller amounts of oxides of nitrogen are produced
by transmission lines during corona, a phenomenon that occurs when air ionizes near isolated
irregularities on the conductor surface such as abrasions, dust particles, raindrops, and insects.
Several studies have quantified the amount of ozone generated and concluded that the amount
produced by even the largest lines in operation (765 kilovolt [kV]) is insignificant (SNYPSC
1978; Scott-Walton et al. 1979; Janes 1978; Varfalvy et al. 1985). Monitoring of ozone levels for
2 years near a Bonneville Power Administration 1,200 kV prototype line revealed no increase in
ambient ozone levels caused by the line (Lee et al. 1989). Similarly, field tests conducted over a
19-month period concerning ozone levels adjacent to Sequoyah transmission lines concluded
that high-voltage lines up to 765 kV do not generate ozone above ambient measurements made
at locations remote from transmission lines (TVA 2013; NRC 2015f). The ozone concentrations
generated by transmission lines are therefore too low to cause any significant effects. The
minute amounts of oxides of nitrogen produced are similarly insignificant. Based on these
considerations, the NRC concludes that the air quality impacts of transmission lines, within this
scope of review (see Section 3.1.7), during the initial LR and SLR terms would be SMALL. The
staff reviewed information from SEISs (for initial LRs and SLRs) completed since development
of the 2013 LR GEIS and identified no new information or situations that would result in different

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impacts for this issue for either an initial LR or SLR term. This is supported by the evidence that
production of ozone and nitrogen oxide are insignificant and do not measurably contribute to
ambient levels of those gases. Potential mitigation measures (e.g., burying transmission lines)
would be very costly and would not be warranted. Therefore, the issue of air quality impacts of
transmission lines would be SMALL for all nuclear plants, and it is a Category 1 issue.
4.3.1.2

Noise

This section evaluates the issue of noise impacts of continued operations and refurbishment
activities during the license renewal (initial LR or SLR) term.
4.3.1.2.1

Noise Impacts

Noise from nuclear plant operations can often be detected offsite relatively close to the plant site
boundary. Sources of noise and the relative magnitude of impacts during normal nuclear power
plant operations are discussed in Section 3.3.3. Major sources of noise at operating nuclear
power plants include cooling towers, turbines, transformers, large pumps, firing range, steam
safety relief valves, and cooling water system motors. Nuclear plant operations have not
changed appreciably with time, and no change in noise levels or noise-related impacts are
expected during the initial LR or SLR term.
Given the industrial nature of the power plant and the number of years of plant operation, noise
from a nuclear plant is generally nothing more than a continuous minor nuisance. However,
noise levels may sometimes exceed the day-night average 55 A-weighted decibels (dBA) level
that the EPA uses as a threshold level to protect against excess noise during outdoor activities
(EPA 1974). For instance, continuous measurements at three noise-sensitive receptors from
Fermi Unit 2 resulted in a day-night sound level of between 55 and 63 dBA (NRC 2016c). While
the day-night sound levels measured are above EPA’s recommended threshold, it does “not
constitute a standard, specification, or regulation,” rather it is intended to provide a basis for
State and local governments establishing noise standards. Furthermore, the day-night sound
levels measured at noise-sensitive receptors near Fermi Unit 2 were below the Federal Housing
Administration guideline of a day-night average sound level of 65 dBA or less (NRC 2016c,
24 CFR Part 51). In 2008, an ambient noise-monitoring survey was performed in areas adjacent
to the Turkey Point site. Measurements (equivalent sound intensity level) at monitoring locations
offsite and beyond the site boundary (including nearest residence, day-care facility, and a park)
ranged from 46 dBA to 67 dBA during the daytime and from 41 dBA to 56 dBA at nighttime.
Audible noise sources contributing to noise levels included traffic, insects, and wind, indicating
that audible sound from the Turkey Point site does not reach these noise-sensitive receptors
(NRC 2016b). Ambient sound level surveys in the vicinity of nuclear power plants have not
approached 80–85 dBA, which is the threshold at which noise levels can become very annoying
(CDC 2022c).
In addition to EPA and U.S. Department of Housing and Urban Development noise threshold
guidelines, local governments can establish noise ordinances. For example, Louisa County,
Virginia, where the North Anna plant is located, has a noise ordinance that limits daytime sound
levels to 75 decibels (dB) and nighttime sound levels to 65 dB for industrial zoning districts
(NRC 2021g). Similarly, Waterford is located in a designated industrial land use area within a
heavy manufacturing zoning district. St. Charles Parish (where Waterford is located) has a noise
ordinance, but the ordinance does not set maximum permissible sounds levels for areas zoned
as industrial (NRC 2018d).

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Nuclear power plants have received noise complaints associated with operational activities. For
instance, Braidwood received noise complaints related to the cooling water discharge system
into the Kankakee River. Prior to 2011, this system produced noticeable noise at the discharge
location. In 2011, Exelon installed a new diffuser for water discharge into the Kankakee River,
which, among other environmental benefits, nearly eliminated noise from the discharge location
(NRC 2015d). Furthermore, Exelon notifies the public about upcoming activities and the
potential for noise via their notification system. The notification system alerts residences and
other locations within 1 mi (1.6 km) of Braidwood prior to planned activities that may affect the
surrounding area. Similarly, in response to complaints regarding activities associated with
nighttime firearm training at the range at Fermi, DTE Electric notifies the nearby municipalities of
upcoming scheduled training at the range and provides information about upcoming activities
(NRC 2016c).
Noise would also be generated by construction-related activities and equipment used during
refurbishment. Noise attenuates rapidly with distance. As a rule of thumb, with a doubling in
distance from a point source the sound level decreases by 6 dB. Additionally, this noise would
occur for relatively short periods of time (several weeks) and is not expected to be
distinguishable from other operational noises at the site boundary or create an adverse impact
on nearby residents.
In the 1996 LR GEIS, the NRC noted that there have been few noise complaints at power
plants, but that noise impacts have been found to be small. Because noise sources at power
plants do not change appreciably over time, the 1996 LR GEIS concluded that noise was not
expected to be a problem at any nuclear plant during the license renewal term and, given the
few noise complaints, no additional mitigation measures are warranted. The magnitude of noise
impacts was therefore determined to be SMALL for all plants, and the issue was designated as
Category 1. The staff reviewed information from SEISs (for initial LRs and SLRs) completed
since development of the 2013 LR GEIS and identified no new information or situations that
would result in different impacts for this issue for either an initial LR or SLR term. The NRC has
found that noise sources and levels are not expected to change from current operations and
therefore would remain similar during the initial LR or SLR term.
Based on these considerations, the NRC concludes that the noise impact of continued nuclear
plant operations during the initial LR and SLR terms and refurbishment would be SMALL for all
plants. Therefore, this is a Category 1 issue.

4.4

Geologic Environment

4.4.1
4.4.1.1

Environmental Consequences of the Proposed Action – Continued Operations
and Refurbishment Activities
Geology and Soils

This issue was added in the 2013 LR GEIS. Geologic and soil conditions at all nuclear power
plants and associated transmission lines have been well established during the current licensing
term. These conditions are expected to remain unchanged or within the range of natural
variability during the 20-year license renewal (initial LR or SLR) term.

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The impact of continued operations and any refurbishment associated with license renewal on
geologic and soil resources would consist of soil disturbance, including sediment and/or any
associated bedrock, for projects such as replacing or adding buildings, roads, parking lots, and
belowground and aboveground utility structures. For such projects, a licensee may also need to
obtain geologic resources (e.g., soil or sand borrow or backfill material, aggregate for road
building or concrete production) from locations on the nuclear power plant site or from offsite
borrow areas or quarries. However, it is more likely that these materials would be obtained from
commercial vendors. Regardless, for onsite activities, implementation of BMPs by the plant
licensee would reduce soil erosion and subsequent impacts on surface water quality. These
practices include, but are not limited to, minimizing the amount of disturbed land, stockpiling
topsoil before ground disturbance, mulching and seeding in disturbed areas, covering loose
materials with temporary covers such as geotextiles, using sediment (silt) fences to reduce
sediment loading to surface water, using check dams to minimize the erosive power of
drainages, and installing proper culvert outlets to direct flows in streams or drainages.
Detailed geotechnical analyses would be required to address the stability of excavations,
foundation footings, and slope cuts for building construction, road creation, or other
refurbishment-related construction projects. Depending on the plant location and design,
riverbank or coastline protection might need to be upgraded, especially at water intake or
discharge structures, if natural flows, such as storm surges, cause an increase in erosion. For
example, at the Point Beach plant, the bluffs along Lake Michigan are subject to erosion from
storm action. The licensee performs necessary shoreline and bank stabilization activities in
accordance with an authorization from the U.S. Army Corps of Engineers (USACE). In 2019, the
licensee initiated a project to construct a new breakwater structure (wave barrier) along the
plant boundary with Lake Michigan. The projected was completed in August 2020. The work
included construction of a new breakwater structure extending north from near the midpoint of
the Point Beach Unit 2 discharge flume for approximately 600 ft (185 m) to an existing
breakwater structure. The second 600 ft (185 m) segment of the breakwater extends south from
near the midpoint of the Point Beach Unit 1 flume and curves back to the existing shoreline. The
breakwater structure consists of large armor stones (dolomite blocks) stacked on the lake
bottom. The project also included installation of additional riprap protection along the shoreline,
extending for 400 linear ft (120 m) and including the shoreline segment between the plant’s two
discharge flumes (NRC 2021f).
Plant-specific environmental reviews conducted by the NRC to date have not identified any
significant impact issues related to continued operations and refurbishment activities on geology
and soils.
The impacts of natural phenomena, including geologic hazards, on nuclear power plant
systems, structures, and components are outside the scope of the NRC’s license renewal
environmental review. As discussed in Section 3.4, nuclear power plants were originally sited,
designed, and licensed in consideration of the geologic and seismic criteria set forth in
10 CFR 100.10(c)(1) and 10 CFR Part 100, Appendix A, and, where applicable, 10 CFR
Part 50, Appendix A. In its license renewal environmental reviews, for instance, the NRC
considers the risk to reactors from seismicity in the evaluation of severe accidents. Where
appropriate, seismic issues are also assessed in the plant-specific safety review that is
performed for license renewals. The NRC also conducts safety reviews prior to allowing
licensees to make operational changes due to changing environmental conditions.
Further, the NRC requires all licensees to take seismic activity into account in order to maintain
safe operating conditions at all nuclear power plants. When new seismic hazard information

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becomes available, the NRC evaluates the new information to determine if any changes are
needed at existing plants, as discussed in Section 1.7.6 of this LR GEIS. This reactor oversight
process, which considers seismic safety, is separate and distinct from the NRC staff’s license
renewal environmental review.
The impact of continued operations and refurbishment on geology and soils during the license
renewal term was considered to be SMALL for all plants and a Category 1 issue in the
2013 LR GEIS. The staff reviewed information from SEISs (for initial LRs and SLRs) completed
since development of the 2013 LR GEIS and identified no new information or situations that
would result in different impacts for this issue for either an initial LR or SLR term. The staff
concludes that the impacts of continued nuclear plant operations during the initial LR or
SLR terms and any refurbishment activities on geology and soils would be the same (SMALL)
for all nuclear plants. As a result, geology and soils is a Category 1 issue.

4.5

Water Resources

Hydrologic and water quality conditions at all nuclear power plants and associated transmission
lines have been well established during the current licensing terms. However, continued
operations and any refurbishment activities could have an impact on water resources during the
license renewal (initial LR or SLR) terms. This section describes the potential impact of these
proposed activities and alternatives on surface water and groundwater resources.
4.5.1

Environmental Consequences of the Proposed Action – Continued Operations
and Refurbishment Activities

Continued operations and any refurbishment activities during the license renewal (initial LR or
SLR) term could affect surface water and groundwater resources in a manner similar to what
has occurred during the current license term (see Sections 3.5.1 and 3.5.2, respectively).
4.5.1.1

Surface Water Resources

For the most part, no significant surface water impacts are anticipated during the license
renewal terms that would be different from those occurring during the current license term.
Certain operational changes (such as a power uprate) affecting surface water would be
evaluated by the NRC in a separate environmental review. For potential impacts on water
resources, the use of surface water is of greatest concern because of the high volumetric flow
rates required for condenser cooling at nuclear power plants. Withdrawals from surface
waterbodies are high for both once-through and closed-cycle cooling systems. Consumptive
water use occurs through evaporation and drift, especially from cooling towers, and may affect
water availability downstream from nuclear power plants along rivers. Associated impacts on
surface water quality may result from the discharge of thermal effluent containing chemical
additives. Other potential impacts on surface water are the result of normal industrial plant
activities during the license renewal term.
The following issues concern impacts on surface water that may occur during the initial LR or
SLR term:
• surface water use and quality (non-cooling system impacts)
• altered current patterns at intake and discharge structures
• altered salinity gradients

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• altered thermal stratification of lakes
• scouring caused by discharged cooling water
• discharge of metals in cooling system effluent
• discharge of biocides, sanitary wastes, and minor chemical spills
• surface water use conflicts (plants with once-through cooling systems)
• surface water use conflicts (plants with cooling ponds or cooling towers using makeup water
from a river)
• effects of dredging on surface water quality
• temperature effects on sediment transport capacity
4.5.1.1.1

Surface Water Use and Quality (Non-Cooling System Impacts)

Continued operations and refurbishment activities could result in the degradation of water
quality within the receiving watershed. Power plant sites and land-disturbing activities can
increase the variety and quantity of pollutants entering receiving waterbodies such as streams,
rivers, and lakes. Pollutants within stormwater runoff from plant sites can include suspended
sediment; pesticides and nutrients from landscaped areas; petroleum products including oil and
grease and toxic chemicals from motor vehicles; spills of hydrocarbon fuels; paints; road salts;
water treatment chemicals including acids and biocides; heavy metals from roof shingles and
motor vehicles; and thermal pollution (i.e., heated stormwater runoff) from impervious surfaces.
These pollutants could potentially harm aquatic and terrestrial species, contaminate recreational
areas, and degrade drinking water supplies.
In an effort to minimize or eliminate impacts on the water quality of receiving waterbodies, BMPs
are typically included as conditions within National Pollutant Discharge Elimination System
(NPDES) permits issued by the EPA, or, where delegated, by individual States. BMPs are
measures used to control the adverse water quality-related effects of land disturbance and
development or industrial activity. They include structural devices designed to remove
pollutants, reduce runoff rates and volumes, and protect aquatic habitats. BMPs also include
nonstructural or administrative approaches, such as training to educate staff in the proper
handling and disposal of potential pollutants.
Permanent or structural BMPs are designed to control pollutants to the maximum extent
practicable during continued operations of the power plant. Extended detention and infiltration
basins are examples of pollutant-removal features designed to remove pollutants based on
volume. Hydrodynamic separator systems (hydrodynamic devices, baffle boxes, swirl
concentrators, or cyclone separators) are examples of pollutant-removal devices that are
typically designed based on flow rate.
Refurbishment activities involving construction-related land disturbance are expected to be
managed by an approved Stormwater Pollution Prevention Plan (SWPPP). Development and
implementation of a SWPPP is normally required as a condition of a NPDES permit. The
SWPPP would indicate the structural and nonstructural BMPs that must be implemented for the
duration of the refurbishment activity. Examples of construction BMPs include use of sediment
(silt) fences, check dams, staked hay bales, sediment ponds, mulching, and geotextile matting
of disturbed areas.

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BMPs and conformance to plant site NPDES permits (individual sitewide or general permits),
encompassing those covering stormwater discharges associated with construction and
industrial activity, are expected to be followed during continued operations and refurbishment
activities. Implementation of spill prevention and control plans would further reduce the
likelihood of any liquid chemical spills.
Continued operations and refurbishment activities will require water for non-cooling-related
purposes, including some consumptive use (i.e., water that is used but not returned to the
source and effectively lost). The water source is dependent on the nuclear power plant site,
water availability, and the nature of any refurbishment activities. Typical water sources at
nuclear power plants are surface water, groundwater, and public domestic (potable) water.
Water may be used during refurbishment activities for concrete production, dust control,
washing stations, facility and equipment cleaning, and soil compaction and excavation
backfilling. However, the impacts due to the volume of water consumed from a surface water
source would be insignificant when compared with that used or consumed by a plant’s cooling
system (either once-through or closed-cycle cooling system).
The use of groundwater for non-cooling system uses would have a minimal impact on the
surface water source similar to that of a direct surface water withdrawal, assuming an
interconnection between the groundwater source and surface waterbody. Groundwater
withdrawal near a waterbody with a disconnected groundwater table would have no effect on
the surface water resource.
The use of public domestic water would reduce the direct consumptive use impacts on surface
water resources. Still, domestic water runoff and water main breaks have the potential to
introduce an additional pollutant (residual chlorine), which could impact water quality. It is
expected that such occurrences would be rare and would be identified and corrected as piped
domestic water is metered at the point of interconnection with a plant’s water distribution
system. Any such occurrences are not expected to present a significant water quality concern
over the license renewal term.
Surface water consumption for non-cooling water-related operational activities is anticipated to
be negligible and limited to uses such as facility and equipment cleaning. As a result, no surface
water use conflicts would be expected.
The impacts of refurbishment on surface water use and quality during the license renewal term
were considered to be SMALL for all plants and designated as a Category 1 issue in the
2013 LR GEIS. Further, non-cooling system operational impacts on water use and quality are
expected to be SMALL, as described above. In addition, if refurbishment took place during a
reactor shutdown, the overall water use by the facility would be greatly reduced. The staff
reviewed information from SEISs (for initial LRs and SLRs) completed since development of the
2013 LR GEIS and identified no new information or situations that would result in different
impacts for this issue for either an initial LR or SLR term. Based on these considerations, the
NRC concludes that the non-cooling system impacts of continued operations and refurbishment
activities on surface water resources during the initial LR and SLR terms would be SMALL for all
nuclear power plants. This is a Category 1 issue.

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4.5.1.1.2

Altered Current Patterns at Intake and Discharge Structures

The large flow rates associated with cooling system water use have the potential to alter current
patterns. The degree of influence depends on the design and location of the intake and
discharge structures and the characteristics of the surface waterbody. The effect on currents
near the intake and discharge locations is expected to be variable and localized, and any
problems would have been mitigated during the early operational period of a nuclear power
plant (NRC 1996). Most nuclear power plants are sited on large bodies of water to make use of
the water for cooling purposes. The size of large rivers, lakes, or reservoirs precludes significant
current alterations except in the vicinity of the structures. For ocean shore, bay, or tidally
influenced river settings, the effect is further reduced when compared with the strong natural
water movement patterns. For example, current patterns were modified at the Oyster Creek
Nuclear Generating Station (Oyster Creek; which permanently shut down in September 2018).
The plant site is located inland from Barnegat Bay in New Jersey. The once-through cooling
system for this plant was created by modifying two small rivers (creeks) originally flowing
parallel into the bay. On the north side of the plant, the South Branch of the Forked River was
enlarged between the plant and the bay to serve as an intake canal. On the south side of the
plant, Oyster Creek was enlarged between the plant and the bay for use as a discharge canal.
Near the plant, the two waterways were joined. Bay water was pulled from the bay through the
intake canal to the plant, against the original flow direction of the lowest reach of the South
Branch of the Forked River. Flow at the mouth of this river was both reversed and significantly
increased, while flow at the mouth of the Oyster Creek discharge canal significantly increased
during plant operations. While current patterns in Barnegat Bay in the immediate vicinity of the
intake and discharge canals were affected by operations, the effect on the overall Barnegat Bay
system was minor (NRC 1996, NRC 2007b).
This issue has no relevance to nuclear power plants relying on cooling ponds or canal systems
because such structures are human-made (excavated earthworks or engineered
impoundments) without natural currents.
Impacts from altered current patterns at intake and discharge structures during the license
renewal term were considered to be SMALL for all plants and designated as Category 1 in the
2013 LR GEIS. The staff reviewed information from SEISs (for initial LRs and SLRs) completed
since development of the 2013 LR GEIS and identified no new information or situations that
would result in different impacts for this issue for either an initial LR or SLR term. Based on
these considerations, the NRC concludes that the impact of altered current patterns at intake
and discharge structures would be SMALL during the initial LR and SLR terms for all nuclear
plants. This is a Category 1 issue.
4.5.1.1.3

Altered Salinity Gradients

This issue relates to the few (operating) nuclear power plants (Table 3.1-2) located on estuaries
and addresses changes in salinity caused by cooling system water withdrawals and discharges
directly to receiving waters. Operation of a cooling system is expected to cause only small,
localized changes to salinity gradients near a power plant (NRC 1996). Using the same example
nuclear power plant site as for the issue of altered current patterns (Section 4.5.1.1.2), the
construction of the Oyster Creek plant (no longer operating) included modification of the lower
reaches of two creeks. These portions of the creeks were originally brackish, with a mix of
freshwater from their upper reaches and tidally influenced bay water. Because of the cooling
system operations, the water quality of these lower reaches had approached that of Barnegat
Bay, with contributions of freshwater from their upper reaches being relatively minor. These

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lower reaches were also affected by occasional dredging activities, and the discharge canal
received water to which heat and chemicals had been added. The salinity changes did not affect
the upper portions of the creeks. In the 1996 LR GEIS, only minor effects had been noted in
Barnegat Bay.
As documented in the 1996 LR GEIS and Calvert Cliffs Nuclear Power Plant (Calvert Cliffs)
SEIS (NRC 1999c), the NRC found that operation of the Calvert Cliffs plant has not had
significant effects on salinity in Chesapeake Bay. Altered salinity gradients are expected to be
noticeable only in the immediate vicinity of the intake and discharge structures.
More recently, in the Surry SLR SEIS, the NRC evaluated the plant’s cooling water withdrawals
and discharges to the tidally influenced James River in Virginia. The range in measured
salinities in the James River for the period 1984 through 2018 indicated no significant effect
from Surry’s operations, based on comparison to salinity data compiled prior to and immediately
after plant startup in 1975. Higher salinity does occur within Surry’s engineered discharge canal
due to the withdrawal of higher salinity water (NRC 2020f).
Impacts from altered salinity gradients at intake and discharge structures during the license
renewal term were considered to be SMALL for all plants and designated as a Category 1 issue
in the 2013 LR GEIS. The staff reviewed information from SEISs (for initial LRs and SLRs)
completed since development of the 2013 LR GEIS and identified no new information or
situations that would result in different impacts for this issue for either an initial LR or SLR term.
Based on these considerations, the NRC concludes that the impact of altered salinity gradients
would be SMALL during the initial LR and SLR terms for all nuclear plants. This is a Category 1
issue.
4.5.1.1.4

Altered Thermal Stratification of Lakes

Because cooling systems typically withdraw from the deeper, cooler portion of the water column
of lakes or reservoirs and discharge to the surface, they have the ability to alter the thermal
stratification of the surface water. This has not been shown to be an issue for rivers or oceans
because of mixing caused by natural turbulence.
A thermal plume of discharge water loses heat to the atmosphere and to the receiving surface
waterbody. It also undergoes mixing with the surface water. In the 1996 LR GEIS, examples
included the Oconee Nuclear Station (Oconee) in South Carolina, where the withdrawal of cool,
deep water for cooling purposes favors warmwater fish species at the expense of coolwater fish.
Mitigation of this effect is possible by modifying the allowable discharge water temperature. In
an example from the McGuire Nuclear Station (McGuire) in North Carolina, a modeling study
indicated that increasing the permitted discharge temperature would reduce the withdrawal of
cool, deep water and conserve coolwater species habitat.
Thermal plumes may be studied through field measurements and modeling studies. For plants
on lakes or reservoirs, the thermal effect on stratification is examined periodically through the
NPDES permit renewal process. For example, as documented in the Point Beach SLR SEIS,
the plant’s Wisconsin-issued NPDES permit imposes a heat-rejection limit on the plant’s cooling
water discharge. This limit accounts for operational changes implemented at Point Beach
associated with the extended power uprate that the NRC approved in 2011 (NRC 2021f).
Problems with thermal stratification due to nuclear power plant operations have not been
encountered.

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Impacts from altered thermal stratification of lakes and reservoirs during the license renewal
term were considered to be SMALL for all plants and were designated as a Category 1 issue in
the 2013 LR GEIS. The staff reviewed information from SEISs (for initial LRs and SLRs)
completed since development of the 2013 LR GEIS and identified no new information or
situations that would result in different impacts for this issue for either an initial LR or SLR term.
Based on these considerations, the NRC concludes that the impact of altered thermal
stratification of lakes would be SMALL during the initial LR and SLR terms for all nuclear plants.
This is a Category 1 issue.
4.5.1.1.5

Scouring Caused by Discharged Cooling Water

The high flow-rate of water from a cooling system discharge structure has the potential to
physically scour sediments from the bed of the receiving waterbody and redeposit them
elsewhere. Scouring will remove fine-grained sediments, resulting in turbidity, and leave behind
coarse-grained sediments.
The degree of scouring depends on the design of the discharge structure and the character of
the sediments. Scouring is expected to occur only in the vicinity of the discharge structure
where flow rates are high. While scouring is possible during reactor startup, operational periods
would typically have negligible scouring. Natural sediment transport processes could bring fresh
sediment into the discharge flow area. These processes include transport due to ocean
currents, tides, river meandering, and storm events.
In the 1996 LR GEIS, scouring had not been noted as a problem at most plants and had been
observed at only three nuclear power plants (Calvert Cliffs, Connecticut Yankee [no longer
operating], and San Onofre Nuclear Generating Station [San Onofre; no longer operating]). The
effects at these plants were localized and minor.
Impacts from scouring caused by discharged cooling water during the license renewal term
were considered to be SMALL for all plants and were designated as a Category 1 issue in the
2013 LR GEIS. The staff reviewed information from SEISs (for initial LRs and SLRs) completed
since development of the 2013 LR GEIS and identified no new information or situations that
would result in different impacts for this issue for either an initial LR or SLR term. Based on
these considerations, the NRC concludes that the impact of scouring caused by discharged
cooling water would be SMALL during the initial LR and SLR terms for all nuclear plants. This is
a Category 1 issue.
4.5.1.1.6

Discharge of Metals in Cooling System Effluent

Heavy metals such as copper, zinc, and chromium can be leached from condenser tubing and
other components of the heat exchange system by circulating cooling water. These metals are
normally addressed in NPDES permits because high concentrations of them can be toxic to
aquatic organisms. Operations at all nuclear power plants are subject to one or more NPDES
permits that require licensees to conduct effluent monitoring and reporting for a wide range of
pollutants that could potentially be discharged in cooling water and comingled effluents. For
example, as described in the Byron initial LR SEIS, the plant’s Illinois-issued NPDES permit
requires that the licensee monitor cooling system blowdown discharges to the Rock River for
various parameters, including the metals zinc, iron, lead, copper, nickel, and chromium
(NRC 2015c). During normal nuclear power plant operations, metal concentrations are normally
below laboratory detection levels. However, plants occasionally undergo planned outages for
refueling or unplanned maintenance, with stagnant water remaining in the heat exchange

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system. During an outage at the Diablo Canyon Power Plant (Diablo Canyon) in California, the
longer residence time of water in the cooling system resulted in elevated copper levels in the
discharge when operations resumed; abalone (Haliotis spp.) deaths were attributed to the
increased copper (NRC 1996). At the H.B. Robinson Steam Electric Plant (Robinson) in
South Carolina, the gradual accumulation of copper in its reservoir resulted in impacts on the
bluegill (Lepomis macrochirus) population. In both cases, copper condenser tubes were
replaced with titanium tubes, and the problem was eliminated (NRC 1996).
Impacts from the discharge of metals in cooling system effluent during the license renewal term
were considered to be SMALL for all nuclear power plants and were designated as a Category 1
issue in the 2013 LR GEIS. The staff reviewed information from SEISs (for initial LRs and SLRs)
completed since development of the 2013 LR GEIS and identified no new information or
situations that would result in different impacts for this issue for either an initial LR or SLR term.
Based on these considerations, the NRC concludes that water quality impacts from the
discharge of metals in cooling system effluent would be SMALL during the initial LR and
SLR terms for all nuclear plants. This is a Category 1 issue.
4.5.1.1.7

Discharge of Biocides, Sanitary Wastes, and Minor Chemical Spills

The use of biocides and other water treatment chemicals is common and is required to control
biofouling and nuisance organisms in plant cooling systems. However, the types of chemicals,
their amounts or concentrations, and the frequency of their use may vary. The use of biocides at
nuclear power plants is discussed generally in Section 3.1.5. Ultimately, any residual biocides
used in the cooling system are discharged to surface waterbodies. The discharge of treated
sanitary waste also occurs at plants. Discharge may occur via onsite wastewater treatment
facilities, via an onsite septic field, or through a connection to a municipal sewage system. Minor
chemical spills collected in floor drains are associated with industry in general and are a
possibility at all nuclear plants. Each of these factors represents a potential impact on surface
water quality.
Discharges of cooling water and other plant wastewaters are monitored through the NPDES
program administered by the EPA, or, most commonly, by delegated individual States. The
NPDES permit contains requirements that limit the flow rates and pollutant concentrations that
may be discharged at permitted outfalls, including chemical residuals from biocides and other
water treatment chemicals. For example, as described in the Fermi initial LR SEIS, the plant’s
Michigan-issued NPDES permit imposes effluent limits and monitoring requirements for residual
chlorine and other listed biocides (used for zebra mussel control) on the plant’s primary outfall to
Lake Erie (NRC 2016c). NPDES permits normally include special conditions such as requiring
preapproval from the regulatory agency for the use of new water treatment chemicals, as well
as requiring that onsite sanitary wastewater treatment facilities be attended by a licensed
operator. The permit may also include biological monitoring parameters that are primarily
associated with the discharge of cooling water. NPDES permits may further include biochemical
monitoring parameters. Discharge from building drains is also addressed in the NPDES permit.
Because of Federal or State regulatory involvement, and the fact that no significant problems
with outfall monitoring have been found, the impacts from the discharge of chlorine and other
biocides and minor spills of sanitary wastes and chemicals during license renewal and
refurbishment were considered to be SMALL for all nuclear power plants and designated as a
Category 1 issue in the 2013 LR GEIS. The staff reviewed information from SEISs (for
initial LRs and SLRs) completed since development of the 2013 LR GEIS and identified no new
information or situations that would result in different impacts for this issue for either an initial LR

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or SLR term. Based on these considerations, the NRC concludes that water quality impacts
from the discharge of biocides, sanitary wastes, and minor chemical spills would be SMALL
during the initial LR and SLR terms for all nuclear plants. This is a Category 1 issue.
4.5.1.1.8

Surface Water Use Conflicts (Plants with Once-Through Cooling Systems)

Nuclear power plant cooling systems may compete with other users relying on surface water
resources, including downstream municipal, agricultural, or industrial users. Once-through and
closed-cycle cooling systems have different water withdrawal and consumption rates. As
reported by Dieter et al. (2018), thermoelectric plant once-through cooling systems return most
of their withdrawn water to the same surface waterbody, with evaporative losses of
approximately 1 percent, compared to 57 percent for closed-cycle (recirculating) cooling
systems.
The interface between a nuclear power plant’s cooling water system and the environment is
relatively large compared to most other plant systems. The cooling water system used at
operating nuclear power plants, as installed at the time the plant was constructed, was selected
both for efficiency and in consideration of site-specific factors such as water availability.
Section 3.1.3 of this LR GEIS discusses the cooling water systems and water sources used at
existing nuclear plant sites, including comparative cooling system performance characteristics.
Surface water use by nuclear plants considered in this LR GEIS is further described in
Section 3.5.1.1, with a quantitative analysis presented in Table 3.5-1. Once-through cooling
systems are still more common than closed-cycle systems at operating nuclear plants, with
once-through systems being prevalent on larger waterbodies. In general, once-through cooling
systems have lower overall consumptive water loss than closed-cycle systems.
Consumptive use by nuclear power plants with once-through cooling systems during the license
renewal term is not expected to change unless power uprates, with associated increases in
water use, are proposed. Because power uprates are a separate licensing action from license
renewal, such uprates would normally require a separate environmental review by the NRC.
Future scenarios for water availability focus on climate change and associated changes in
precipitation and temperature patterns. Since the beginning of the last century, annual
precipitation has increased on average by 4 percent across the United States with increases in
the Northeast, Midwest, and Great Plains and decreases over parts of the Southeast and
Southwest. The frequency and intensity of heavy precipitation have increased average annual
precipitation, with the highest observed changes occurring across the Northeast and Midwest.
Climate models project that these trends will continue. Annual average temperature has
increased by 1.2 degrees Fahrenheit (°F) (0.7 degrees Celsius [°C]) across the contiguous
United States for the period 1986–2016 relative to 1901–1960. In the coming decades, annual
average temperatures are projected to increase by about 2.2°F (1.2°C) (USGCRP 2018).
Increased temperatures and/or decreased rainfall would result in lower river flows, increased
cooling pond evaporation, and lowered water levels in the Great Lakes or reservoirs. Climate
change-induced impacts on water availability are less pronounced across large watersheds
(large river systems and lakes). As a result, surface water withdrawals by nuclear power plants
using once-through cooling systems would be less likely to affect water availability because
such nuclear plants are generally located in large watersheds, and they return nearly all of the
water they withdraw to the same surface waterbody. While weather will vary from year to year,
the results of climate change models and the projected changes to surface water runoff support
the likelihood of increases in runoff across the eastern United States and decreases in runoff in
the western United States, where water remains less available due to drought and decreases in

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winter snowpack. Regardless of overall climate change, droughts could result in problems with
water supplies and allocations. Because future agricultural, municipal, and industrial users
would continue to share their demands for surface water with power plants, conflicts might arise
if the availability of this resource decreased. This situation would then necessitate decisions by
local, State, and regional water-planning officials.
Population growth around nuclear power plants has caused increased demand on municipal
water systems, including systems that rely on surface water. Municipal intakes located
downstream of a nuclear power plant could experience water shortages, especially in times of
drought. Water demands upstream of a plant could affect the water availability at the plant’s
intake.
In the 2013 LR GEIS, the impacts of continued operations and refurbishment on water use
conflicts associated with once-through cooling systems were considered to be SMALL and were
designated as a Category 1 issue. The staff reviewed information from SEISs (for initial LRs and
SLRs) completed since development of the 2013 LR GEIS and identified no new information or
situations that would result in different impacts for this issue either for an initial LR or SLR term.
Based on these considerations, the NRC concludes that surface water use conflicts from the
continued operation of nuclear plants that use once-through cooling would be SMALL during the
initial LR and SLR terms. This is a Category 1 issue.
4.5.1.1.9

Surface Water Use Conflicts (Plants with Cooling Ponds or Cooling Towers Using
Makeup Water from a River)

Nuclear power plant cooling systems may compete with other users relying on surface water
resources, including downstream municipal, agricultural, or industrial users. As discussed in
Section 4.5.1.1.8, with regard to once-through cooling systems, nuclear plant cooling system
configurations vary across different plant sites, requiring consideration of the site- and plantspecific factors affecting consumptive water use and which could result in surface water use
conflicts. Section 3.1.3 of this LR GEIS discusses the cooling water systems and water sources
used at existing nuclear plant sites, including comparative cooling system performance
characteristics. Surface water use is further described in Section 3.5.1.1 of this LR GEIS, with a
quantitative analysis presented in Table 3.5-1.
This issue concerns consumptive water use impacts from nuclear power plants using closedcycle (also known as recirculating) cooling systems. Closed-cycle cooling is not completely
closed, because the system discharges blowdown water to a surface waterbody and withdraws
water for makeup of both the consumptive water loss due to evaporation and drift (for cooling
towers) and blowdown discharge. For plants using cooling towers, while the volume of surface
water withdrawn is substantially less than once-through systems for a similarly sized nuclear
power plant, the makeup water needed to replenish the consumptive loss of water to
evaporation can be substantial (see Section 3.5.1.1, Table 3.5-1). As reported by the
U.S. Geological Survey (USGS 2019b), consumptive water use in thermoelectric power plants
with recirculating cooling systems can be up to 74 percent of the withdrawal flow rate. Cooling
ponds also require makeup water as a result of naturally occurring evaporation, evaporation of
the warm effluent, the potential need for periodic blowdown to maintain pond chemistry, and
possible seepage to groundwater.
Consumptive use by plants with cooling ponds or cooling towers using makeup water from a
river during the license renewal term is not expected to change unless power uprates, with
associated increases in water use, occur. Such uprates would normally require a separate

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environmental review by the NRC. Any river, regardless of size, can experience low-flow
conditions of varying severity during periods of drought and changing conditions in the affected
watershed, such as upstream diversions and use of river water. However, the potential for direct
impacts on instream flow and potential water availability for other users from nuclear power
plant surface water withdrawals are greater for smaller (i.e., low-flow1) rivers.
As stated earlier (see Section 4.5.1.1.8), increased temperatures and/or decreased rainfall
would result in lower river flows, increased cooling pond evaporation, and lowered water levels
in lakes or reservoirs. Regardless of overall climate change, droughts could result in problems
with water supplies and allocations. Conflicts might arise due to competing agricultural,
municipal, and industrial user demands for surface water with power plants. Closed-cycle
cooling systems are more susceptible to these issues than once-through cooling systems
because they consume more water per unit volume of water withdrawn from the water source.
For this reason, climate change is more of a potential concern for water use conflicts associated
with nuclear power plants with closed-cycle cooling systems.
Population growth around nuclear power plants has caused increased demand on municipal
water systems, including systems that rely on surface water. Municipal intakes located
downstream from a nuclear power plant could experience water shortages, especially in times
of drought. Similarly, water demands upstream from a nuclear power plant could affect the
water availability at the plant’s intake. Water availability problems for downstream habitat and
users may also be a concern.
As discussed in the 2013 LR GEIS, potential water use conflicts have been documented for
nuclear power plants with closed-cycle cooling systems. State and Federal regulatory agencies
have imposed surface water withdrawal limits on a number of operating nuclear power plants
with cooling towers and cooling ponds. The Limerick plant is equipped with natural draft cooling
towers, on the Schuylkill River in Pennsylvania. It is cited as an example of a plant in the
1996 LR GEIS on which limits were imposed on the rate of withdrawal from a river for the
purpose of avoiding water use conflicts, including downstream water availability and water
quality. As further documented in the Limerick initial LR SEIS, plant operations are subject to
low-flow augmentation requirements during low river flow to mitigate surface water use conflicts
(NRC 2014d). In another example, as documented in the Braidwood initial LR SEIS, the plant’s
makeup water withdrawal from the Kankakee River to its cooling pond is subject to a maximum
withdrawal rate imposed by the State of Illinois (NRC 2015d).
Water use conflicts associated with plants with cooling ponds or cooling towers using makeup
water from a river with low flow are considered to vary among sites because of differing
site-specific factors, such as makeup water requirements, water availability (especially in terms
of varying river flow rates), changing or anticipated changes in population distributions, or
changes in agricultural or industrial demands. The staff reviewed information from SEISs (for
initial LRs and SLRs) completed since development of the 2013 LR GEIS and identified no new
information or situations that would result in different impacts for this issue for either an initial LR
or SLR term.
Based on this evaluation, the NRC concludes that surface water use conflicts from the
continued operation of nuclear power plants with cooling ponds or cooling towers using makeup
water from a river could be SMALL or MODERATE during the initial LR and SLR terms,
1

A river with low flow was previously defined in 10 CFR 51.53(c)(3)(ii)(A) and in the 1996 LR GEIS as
one with an annual flow rate that is less than 3.15  1012 ft3/yr (9  1010 m3/yr) (100,000 ft3/s [2,830 m3/s]).

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depending on factors such as plant-specific design characteristics affecting consumptive water
use, the characteristics of the waterbody serving as the source for makeup water, and the
amount of competing use for that water. Because the impact could vary among nuclear plants,
this is a Category 2 issue.
4.5.1.1.10 Effects of Dredging on Surface Water Quality
Dredging in the vicinity of surface water intakes, canals, and discharge structures is undertaken
by nuclear power plant licensees to remove deposited sediment and maintain the function of
plant cooling systems. Dredging may also be needed to maintain barge shipping lanes. Whether
accomplished by mechanical, suction, or other methods, dredging disturbs sediments in the
surface waterbody and affects surface water quality by temporarily increasing the turbidity of the
water column. In areas affected by industries, dredging can also mobilize heavy metals,
polychlorinated biphenyls, or other contaminants in the sediments.
The frequency of dredging depends on the rate of sedimentation. At the Oyster Creek plant in
New Jersey (which permanently shut down in September 2018), dredging took place during site
construction to create canals for the once-through cooling system (NRC 2007b). Depth
measurements were performed there every 2 years, and dredging took place on portions of the
canal system during operations. At the Susquehanna Steam Electric Station (Susquehanna) in
Pennsylvania, the plant’s river intake and diffuser pipe are dredged annually (NRC 2009c).
More recently, as documented by the NRC in the Surry SLR SEIS, the licensee conducts
maintenance dredging of its cooling water intake channel in the James River every 3 to 4 years
in accordance with a USACE permit. The licensee also performs debris removal on an
as-needed basis from its low-level intake structure under a USACE Nationwide Permit
(NRC 2020f).
In general, maintenance dredging affects localized areas for a brief period of time. Dredging
operations are performed under permits issued by the USACE and possibly by State or local
agencies. The physical alteration of waterbodies is regulated by Federal and State statutes
under Section 401 (Certification) and Section 404 (Permits) of the Clean Water Act (CWA;
33 U.S.C. § 1251 et seq.). The USACE regulates the discharge of dredged and/or fill material
under Section 404, while Section 401 requires the applicant for a Section 404 permit to also
obtain a Water Quality Certification from the State in order to confirm that the discharge of fill
materials will be in compliance with applicable State water quality standards. If dredging could
affect threatened or endangered species or critical habitat, as established under the
Endangered Species Act (ESA; 16 U.S.C. § 1531 et seq.), the USACE must consult with the
U.S. Fish and Wildlife Service (FWS) or the National Marine Fisheries Service (NMFS) before it
makes a permit decision. When issuing a Section 404 permit, the USACE also considers other
potential impacts on aquatic resources, archaeological resources, Tribal concerns, and the
permitting requirements of State and local agencies. The permitting process may include
planning for the sampling and disposal of the dredged sediments.
The impact of dredging has not been found to be a problem at operating nuclear power plants.
Dredging has localized effects on water quality that tend to be short-lived. The staff reviewed
information from SEISs (for initial LRs and SLRs) completed since development of the
2013 LR GEIS and identified no new information or situations that would result in different
impacts for this issue for either an initial LR or SLR term. Based on these considerations, the
NRC concludes that the impact of dredging on water quality would be SMALL during the
initial LR and SLR terms for all nuclear plants. This is a Category 1 issue.

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4.5.1.1.11 Temperature Effects on Sediment Transport Capacity
Increased temperature and the resulting decreased viscosity have been hypothesized to change
the sediment transport capacity of water, leading to potential sedimentation problems, altered
turbidity of rivers, and changes in riverbed configuration. As referenced in the 2013 LR GEIS,
there is no indication that this has been a significant problem at operating power plants.
Examples of altered sediment characteristics are more likely the result of power plant structures
(e.g., jetties or canals) or current patterns near intakes and discharges; such alterations are
readily mitigated.
Based on review of literature and operational monitoring reports, consultations with utilities and
regulatory agencies, and public comments on previous license renewal reviews, there is no
evidence that temperature effects on sediment transport capacity have caused adverse
environmental effects at any existing nuclear power plant. Regulatory agencies have expressed
no concerns regarding the impacts of temperature on sediment transport capacity. Furthermore,
because of the small area near a nuclear power plant affected by increased water temperature,
it is not expected that plant operations would have a significant impact. No change in the
operation of the cooling system is expected during the license renewal term, so no changes in
the effects on sediment transport capacity are anticipated. The staff reviewed information from
SEISs (for initial LRs and SLRs) completed since development of the 2013 LR GEIS and
identified no new information or situations that would result in different impacts for this issue for
either an initial LR or SLR term. Based on these considerations, the NRC concludes that effects
on sediment transport capacity would continue to be of SMALL significance during the initial LR
and SLR terms for all plants. This is a Category 1 issue.
4.5.1.2

Groundwater Resources

Operational activities during the license renewal term would be similar to those occurring during
the current license term. The impact issues of concern are availability of groundwater and the
effect of nuclear plant operations on groundwater quality.
The following issues concern impacts on groundwater that may occur during the license renewal
(initial LR or SLR) term:
• groundwater contamination and use (non-cooling system impacts)
• groundwater use conflicts (plants that withdraw less than 100 gallons per minute [gpm])
• groundwater use conflicts (plants that withdraw more than 100 gallons per minute [gpm])
• groundwater use conflicts (plants with closed-cycle cooling systems that withdraw makeup
water from a river)
• groundwater quality degradation resulting from water withdrawals
• groundwater quality degradation (plants with cooling ponds), consolidation of two issues from
the 2013 LR GEIS: (1) groundwater quality degradation (plants with cooling ponds in salt
marshes) and (2) groundwater quality degradation (plants with cooling ponds at inland sites)
• radionuclides released to groundwater

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4.5.1.2.1

Groundwater Contamination and Use (Non-Cooling System Impacts)

As indicated in Section 3.5.2, the original construction of some nuclear plants required
dewatering of a shallow aquifer, and operational dewatering takes place at some plants,
including for groundwater contaminant plume control. This is accomplished by systems of
pumping wells or drain tiles. Continued operations and refurbishment activities during the
initial LR or SLR term are not expected to require any significant dewatering that would have an
incremental effect on groundwater availability over that which has already taken place. Such
dewatering impacts are expected to remain SMALL and confined to the boundaries of
operating plants.
The contamination of soil and underlying groundwater can result from general industrial
practices at any site and is not limited to those occurring at nuclear power plants. Such
industrial practices can be evaluated generically, because they are common to industrial
facilities and nuclear power plants. Activities that result in contamination may include the use of
solvents, hydrocarbon fuels (diesel and gasoline), heavy metals, or other chemicals. These
materials all have the potential to affect soils, sediments, and groundwater if released.
Furthermore, contaminants present in the soil can act as long-term sources of contamination to
underlying groundwater, depending on the severity of the spill.
Based on previous plant-specific reviews, these types of groundwater and soil contamination
problems have occurred at some operating plants. Release of contaminants into groundwater
and soil degrades the quality of these resources, even if applicable groundwater quality
standards are not exceeded. This includes de minimis quantities of contaminants that do not
typically require reporting to regulatory agencies because they are below applicable threshold
quantities and/or have been promptly remediated and would not otherwise pose a long-term
threat to human health and the environment. Groundwater and soil contamination from common
industrial practices can occur during routine plant operation and maintenance efforts or be
associated with refurbishment activities.
Historical examples of the types of contamination that may be present at a nuclear power plant
include hydrocarbon leaks or spills at a storage tank, leaked or spilled solvents from barrels,
and a hydraulic oil-line break (NRC 2006d); thallium in soil at a seepage pit, heavy metals in soil
at a sand blasting site, a diesel fuel-line leak, methyl tertiary butyl ether from spills of a gasoline
storage tank, and polychlorinated biphenyls in soil as a result of former dielectric fluid use
(NRC 2007b); hydrocarbon spills and sulfuric acid leaks (NRC 2009c); and sodium hypochlorite
solution spilled to soil, diesel fuel spills to groundwater, sewage discharged to the ground from a
sanitary sewer line break, and nonradioactive oily water spilled to the ground from an oil/water
separator (NRC 2016c). Some of these situations have required regulatory involvement by
State agencies during both monitoring and remediation phases. Remediation has taken place in
the form of excavation and recovery wells. In these instances, all contamination was either
remediated with no further action required by regulatory agencies or contamination was
confined to the plant site with remediation continuing until completed. Nevertheless, the number
of occurrences of such problems can be minimized by means of proper chemical storage,
secondary containment, and leak-detection equipment. In addition, nuclear plants have their
own programs for handling chemicals, waste, and other hazardous and toxic materials in
accordance with Federal and State regulations. Environmental permits held by nuclear power
plant licensees (e.g., NPDES permits) generally require the use of BMPs to prevent pollutant
releases to the environment. Continued implementation of programs and procedures such
as pollution and spill prevention and control plans including BMPs (e.g., good housekeeping

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of the plant site, preventive maintenance, routine inspections, etc.) would reduce the
likelihood of any inadvertent releases to soils and/or groundwater.
An additional source of groundwater contamination can be the use of wastewater disposal
ponds or lagoons. At the Donald C. Cook Nuclear Plant (D.C. Cook) in Michigan, permitted
wastewater ponds have been used for receiving treated sanitary wastewater and for process
wastes from the turbine room sump. Groundwater monitoring showed that concentrations of
water quality parameters had increased to levels above background but below drinking water
standards (EPA maximum contaminant levels) (NRC 2005c). As a result, in an arrangement
with the county, the use of groundwater by other users in a designated area was restricted and
the affected groundwater was limited to the southwestern portion of the plant property.
In contrast, a number of licensees have continued to operate treatment ponds and lagoons
without significant adverse impact. As described in the Sequoyah initial LR SEIS, the licensee
operated two former metal-cleaning waste ponds that discharged to an NPDES internal
monitoring point to the plant’s diffuser pond system. Ultimately, this system discharged collected
wastewater through the plant’s submerged diffuser structure into the Chickamauga Reservoir
(NRC 2015f). In a more recent example, as described by the NRC in the River Bend initial
LR SEIS, the licensee operated two sets of open aeration and sedimentation lagoons located at
the sanitary wastewater treatment plant. The lagoons received sanitary waste from across the
plant. As a safeguard, waste from sinks and drains within the plant containing waste that was
known to be or was potentially contaminated with chemicals or radioactivity was physically
separated from the sanitary drains. Effluent from the system was discharged to an
NPDES-permitted outfall (NRC 2018c).
Contaminants in wastewater disposal ponds and lagoons, whether lined or unlined, at a plant
have the potential to enter groundwater and soils. However, the use of wastewater disposal
ponds and lagoons is subject to discharge authorizations under the NPDES and other
applicable State wastewater discharge permit and monitoring programs.
Remediation of groundwater contamination can involve long-duration cleanup processes that
depend on the types, properties, and concentrations of the contaminants; aquifer properties;
groundwater flow field characteristics; and remedial objectives. Contaminants may be able to
migrate to onsite potable wells or to the wells of offsite groundwater users. Groundwater
monitoring programs, including monitoring of onsite drinking water quality in accordance with
safe drinking water regulations, would be expected to identify problems before contaminated
groundwater reached receptors; however, monitoring wells need to be present and in proper
locations in order to detect contaminants.
In the 2013 LR GEIS, the NRC found that the impact of continued operations and refurbishment
activities on groundwater use and quality unrelated to cooling system operations would be
SMALL for all nuclear plants. The staff reviewed information from SEISs (for initial LRs and
SLRs) completed since development of the 2013 LR GEIS and identified no new information or
situations that would result in different impacts for this issue for either an initial LR or SLR term.
Based on these considerations, the NRC concludes that the impact of non-cooling related
groundwater extraction on groundwater availability would be SMALL during the initial LR and
SLR terms for all nuclear plants. Further, the impact of plant industrial practices and their impact
on groundwater quality would continue to be SMALL during the initial LR and SLR terms for all
nuclear plants. This is a Category 1 issue.

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4.5.1.2.2

Groundwater Use Conflicts (Plants That Withdraw Less Than 100 Gallons
per Minute [gpm])

Water wells are commonly used at nuclear power plant sites to provide water for certain
operational, maintenance, and refurbishment needs, including the potable water system,
although municipal water is available at some nuclear plants (see Section 3.5.2.1). At some
sites, groundwater is the source for the makeup and service water systems. In this case, the
water undergoes treatment to prepare it for its intended use. Groundwater may also be pumped
or otherwise extracted to lower water levels and to provide for hydraulic containment or
extraction of contaminated groundwater.
The pumping of groundwater creates a cone of depression in the potentiometric surface around
the pumping well. The amount the water table or potentiometric surface declines and the overall
extent of the cone depend on the pumping rate, characteristics of the aquifer (e.g., its
permeability), whether the aquifer is confined or unconfined, and certain boundary conditions
(including the nearby presence of a hydrologically connected surface waterbody). Generally,
plants with a peak withdrawal rate of less than 100 gpm (378 liters per minute [Lpm]) do not
have a significant cone of depression. Depending upon hydrogeologic conditions and siting
factors, withdrawal rates in excess of 100 gpm (378 Lpm) may not create conflicts, either
directly in terms of water availability or indirectly in terms of degradation in aquifer water quality.
The potential for nuclear plant production wells to cause conflicts with other groundwater users
would depend largely on the proximity of other wells. As stated in the 2013 LR GEIS, cones of
depression usually do not extend past the property boundary, thereby reducing the possibility of
a groundwater use conflict.
For example, as documented in the Peach Bottom SLR SEIS, three active groundwater
production wells supply water for miscellaneous, nonpotable uses across the plant site. In total,
these wells withdraw a maximum of about 15 gpm (57 Lpm) of water from the crystalline rock
aquifer. The NRC found that this groundwater withdrawal would be unlikely to affect offsite
domestic water supplies (NRC 2020g).
In the 2013 LR GEIS, the groundwater impacts from withdrawals of less than 100 gpm
(378 Lpm) associated with continued operations during the license renewal term were found to
be SMALL for all nuclear plants and designated as Category 1. The staff reviewed information
from SEISs (for initial LRs and SLRs) completed since development of the 2013 LR GEIS and
identified no new information or situations that would result in different impacts for this issue
either during an initial LR or SLR term. Based on these considerations, the NRC concludes that
groundwater use conflicts for all nuclear plants that withdraw less than 100 gpm (378 Lpm)
would be SMALL during the initial LR and SLR terms. This is a Category 1 issue.
4.5.1.2.3

Groundwater Use Conflicts (Plants That Withdraw More Than 100 Gallons
per Minute [gpm])

Nuclear power plants withdraw groundwater for various purposes. Most plants use groundwater
to supply their potable water and service water needs. In some cases, groundwater is pumped
to intentionally lower high water tables, or for the purpose of controlling or remediating
groundwater contamination. At the Grand Gulf plant in Mississippi, Ranney wells in the
Mississippi River alluvium are used to provide cooling system makeup water (see
Section 3.5.2.1).

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As described in the section above, the pumping of groundwater is expected to create a cone of
depression around the well, with the degree of aquifer dewatering dependent on various factors.
A nuclear plant may have several wells, with combined pumping in excess of 100 gpm
(378 Lpm). Overall site pumping rates of this magnitude have the potential to create conflicts
with other local groundwater users if the cone of depression extends to the offsite well(s). Large
offsite pumping rates for municipal, industrial, or agricultural purposes may, in turn, lower the
water level at power plant wells. For any user, allocation is normally determined though a
State-issued permit.
In the South Texas initial LR SEIS (NRC 2013b), the NRC evaluated the potential for
groundwater use conflicts from operation of the plant’s five onsite groundwater production wells
completed in the confined Deep Chicot aquifer and located near the plant site boundary. Over a
10-year period, the site’s actual groundwater withdrawals averaged 768 gpm (2,910 Lpm). The
licensee maintained a permit from the Coastal Plains Groundwater Conservation District to
withdraw groundwater at a rate of approximately 1,860 gpm (7,040 Lpm). The NRC performed a
confirmatory analysis of the licensee’s analysis of potential aquifer drawdown in the Deep
Chicot aquifer after 40 and 60 years of pumping for an offsite production well and also
performed drawdown analyses out to distances of 1 and 5 mi (1.6 and 8 km). The NRC found
that while operation of the South Texas production wells and associated drawdown could impact
the pumping lift of nearby offsite wells, the overall increase in drawdown in the aquifer over an
additional 20 years beyond the current license period would be less than 1 ft (0.3 m). This would
have a negligible impact on neighboring wells and the NRC concluded that groundwater use
conflicts from groundwater withdrawals would be SMALL (NRC 2013b).
As described in the Callaway initial LR SEIS (NRC 2014f), the licensee maintained three deep
groundwater wells to supply groundwater for plant uses. Potable groundwater was being
supplied to the plant at a rate of 33 gpm (124 Lpm). Another well located near the Missouri
River was used to lubricate intake structure pump bearings with a usage rate of 120 gpm
(454 Lpm). Groundwater was also being withdrawn from the backfill surrounding the nuclear
island by a sump pump at a rate of 65 gpm (246 Lpm). Total groundwater withdrawal was
218 gpm (825 Lpm). The NRC determined that groundwater withdrawals at Callaway would
likely have little impact on groundwater use as a result of the relatively small amount of
groundwater consumed and the good aquifer yields in the area. The NRC concluded that the
impact of groundwater consumption at Callaway on groundwater availability was SMALL
(NRC 2014f).
In the Turkey Point SLR SEIS, the NRC evaluated the potential groundwater use conflicts
associated with the licensee’s sitewide groundwater withdrawals from the Biscayne and Upper
Floridan aquifers (NRC 2019c). In 2018, the licensee’s groundwater withdrawals from the
Biscayne aquifer averaged 12.7 million gallons per day (Mgd) (48 million liters per day [MLd]).
These withdrawals were associated with operating a site recovery well system installed to
extract hypersaline groundwater from near the base of the Biscayne aquifer and to limit the
operational influence of the plant’s cooling canal system (CCS) on the regional saltwater
interface. Construction and operation of this recovery well system was instituted by the licensee
in order to meet the requirements of a Consent Agreement with the Miami-Dade County Division
of Environmental Resources Management and a Consent Order issued by the Florida
Department of Environmental Protection. As also described in the SEIS, the licensee operates
the recovery well system under a State-issued permit (NRC 2019c).
During 2018, the licensee’s groundwater withdrawals from the Upper Floridan aquifer averaged
20.3 Mgd (76.8 MLd). This total included about 12.7 Mgd (48.1 MLd) associated with

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groundwater withdrawn and discharged into the Turkey Point CCS for salinity management
(freshening) with the remainder (about 7.6 Mgd [28.8 MLd]) withdrawn for other site uses. The
licensee’s groundwater usage from the Upper Floridan aquifer is governed by a State power
plant site certification issued for Turkey Point by the State of Florida Siting Board.
In consideration of groundwater modeling performed in support of the referenced withdrawals,
projected drawdowns in affected aquifers, potential impacts on other groundwater users, and
conditions imposed by State regulators, the NRC concluded that the potential for groundwater
use conflicts from the licensee’s groundwater withdrawals would be SMALL for the Biscayne
aquifer and MODERATE for the Upper Floridan aquifer during the Turkey Point SLR term
(NRC 2019c).
As described for the Turkey Point plant, this is the first time the NRC has identified groundwater
use conflicts at an operating nuclear power plant. The NRC considers this to be a unique
occurrence because the licensee has the need to withdraw large volumes of groundwater for
salinity management and groundwater remediation at a site located within a complex
hydrogeologic setting. For most operating nuclear power plants, no significant change in water
well systems would be expected over the license renewal term. If a conflict did occur, it might be
possible to resolve it if the power plant relocated its well or wellfield to a different part of the
property. The siting of new wells would be determined through a hydrogeologic assessment and
governed by applicable production well siting, construction, and groundwater allocation
permitting processes.
In the 2013 LR GEIS, groundwater use conflicts were considered for plants that withdraw more
than 100 gpm (378 Lpm) or plants that use Ranney wells. The NRC concluded that the impacts
of continued operations and refurbishment and their contribution to groundwater use conflicts
would not necessarily be the same at all nuclear plant sites (i.e., a Category 2 issue) because of
site-specific factors (e.g., well pump rates, well locations, and hydrogeologic factors) and that
the impacts could be SMALL, MODERATE, or LARGE. The staff reviewed information from
SEISs (for initial LRs and SLRs) completed since development of the 2013 LR GEIS and
identified no new information or situations that would result in different impacts for this issue for
either an initial LR or SLR term. Based on this evaluation, the NRC concludes that groundwater
use conflicts for nuclear plants that withdraw more than 100 gpm (378 Lpm) could be SMALL,
MODERATE, or potentially LARGE during the initial LR and SLR terms, depending on the
plant-specific characteristics described above. This is a Category 2 issue.
4.5.1.2.4

Groundwater Use Conflicts (Plants with Closed-Cycle Cooling Systems That
Withdraw Makeup Water from a River)

In the case of nuclear power plants with cooling towers or cooling ponds that rely on a river for
makeup of consumed (evaporated) cooling water, it is possible that water withdrawals from the
river could lead to groundwater use conflicts with other groundwater users. This situation could
occur because of the interaction between groundwater and surface water, especially in the
setting of an alluvial aquifer in a river valley. Consumptive use of the river water, if significant
enough to lower the river’s water level, would also influence water levels in the alluvial aquifer.
Shallow wells of nearby groundwater users could therefore have reduced water availability or go
dry. During times of drought, the effect would occur naturally, although withdrawals for makeup
water would increase the effect. In the 1996 LR GEIS, a situation at the Duane Arnold Energy
Center (Duane Arnold) in Iowa (which permanently shut down on August 10, 2020) was
described in which a reservoir on a small tributary was used as a secondary supply of makeup
water for the plant’s cooling towers. During low-flow conditions in the plant’s usual source of

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water, the Cedar River, the plant was not allowed to withdraw river water. Instead, it used the
reservoir temporarily. In such a situation, because the high rate of water usage can lower
the water level in the reservoir significantly, local users of shallow groundwater may be
affected, particularly during times of drought affecting a small river. Similar to other water
resources related issues described in this section, such conflicts are highly dependent on the
area’s hydrogeologic framework and the locations, depths, and pump rates of wells, in addition
to the amount that the surface water level declines. The NRC’s license renewal environmental
reviews performed since 2013 have revealed no tangible instances where this issue is of
concern.
As described in the South Texas initial LR SEIS (NRC 2013b), the NRC assessed the impact of
the licensee’s withdrawal of water from the lower Colorado River as makeup for the plant’s main
cooling reservoir. The NRC considered potential impacts on the Shallow Chicot aquifer river
discharges and the alluvial aquifer that separates the Shallow Chicot aquifer from the Colorado
River. The Shallow Chicot aquifer is used primarily for low-yield livestock watering near the plant
site, and this shallow aquifer is hydraulically separated from the regional Deep Chicot aquifer.
Separately, withdrawals from the lower Colorado River during lower river flow are regulated by a
Certificate of Adjudication for water use. The NRC found, in part, that the Shallow Chicot aquifer
would not be substantially influenced by the bank storage effects of alluvial aquifer recharge and
discharge to the lower Colorado River. Therefore, the NRC concluded that continued
withdrawals of surface water from the river for operation of South Texas during low-flow periods
would have a SMALL impact on recharge to the alluvial aquifer during the license renewal term
(NRC 2013b).
In the 2013 LR GEIS, groundwater use conflicts were evaluated for plants that use cooling
towers withdrawing makeup water from a river during continued operations and refurbishment.
The NRC found that that conflicts would not necessarily be the same at all nuclear power plant
sites because of site-specific factors (e.g., the amount of surface water decline, well pump rates,
well locations, and hydrogeologic conditions). The resulting impact could be SMALL,
MODERATE, or LARGE. Therefore, this was considered a Category 2 issue. The staff reviewed
information from SEISs (for initial LRs and SLRs) completed since development of the
2013 LR GEIS. Based on this evaluation, the NRC concludes that groundwater use conflicts for
nuclear plants with closed-cycle cooling systems that withdraw makeup water from a river could
have SMALL, MODERATE, or LARGE impacts during the initial LR and SLR terms, depending
on the site-specific characteristics of surrounding areas described above. This is a Category 2
issue.
4.5.1.2.5

Groundwater Quality Degradation Resulting from Water Withdrawals

This issue considers the possibility of groundwater quality becoming degraded as a result of
drawing water of potentially lower quality into an aquifer.
A well near a river may draw lower quality river water into the aquifer as a function of the
interaction between groundwater and surface water. An example of this type of hydrologic
interaction is the use of Ranney wells (see Section 3.5.2.1) at the Grand Gulf plant in
Mississippi. The resulting induced infiltration of Mississippi River water into the alluvial aquifer
was discussed in the 1996 LR GEIS. This aspect of Ranney well operation was reexamined by
the NRC in the Grand Gulf initial LR SEIS (NRC 2014e). At Grand Gulf, the sandstone layers
comprising the Catahoula aquifer underlie the Mississippi River Alluvial aquifer. The analysis in
the SEIS confirms that the water quality from the plant’s Ranney wells that pump water from the
Mississippi River Alluvial aquifer is nearly identical to the water quality of the Mississippi River.

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As also stated in the SEIS, the transmissivity (ability of an aquifer to transmit water) of the
Catahoula aquifer is so substantially less than that of the Mississippi River Alluvial aquifer that
wells pumping water from the Mississippi River Alluvial aquifer would obtain their water as
induced infiltration from the Mississippi River rather than from upward discharge of groundwater
from the Catahoula aquifer. As a result, any groundwater contamination entering the Mississippi
River Alluvial aquifer would likely remain in the Mississippi River Alluvial aquifer or discharge
into the Mississippi River, rather that migrating to deeper aquifers (NRC 2014e).
While site-specific hydrogeologic factors and well design may provide some control of the flow
of surface water to the well, the bulk of the groundwater pumped by a well in an alluvial aquifer
near a river is expected to be induced surface water, with a smaller component of groundwater
from the direction opposite the river. If well pumping is continuous, the only portion of the
shallow aquifer significantly affected by induced infiltration remains in the capture zone of the
well(s). Therefore, the portion of the aquifer with water quality parameters approaching those of
the river water would usually be located on the power plant’s property.
Wells in a coastal setting (e.g., ocean shore or estuary) have the potential to cause saltwater
intrusion into the aquifer. This water quality problem is a common concern for large pumping
centers associated with municipal or industrial users. The degree of saltwater intrusion depends
on the cumulative pumping rates of wells, their screen depths, and hydrogeologic conditions.
Deep, confined aquifers, for example, may be separated from saline aquifers closer to the
surface. However, as evaluated in the 2013 LR GEIS, the potential for inducing saltwater
intrusion was considered to be of SMALL significance at all sites because groundwater
consumption from confined aquifers for potable and service water uses by nuclear power plants
is a small fraction of groundwater use in all cases. Where saltwater intrusion has historically
been a problem, the large users have been those related to agricultural (irrigation) and
municipal water supply uses.
In the Turkey Point SLR SEIS (NRC 2019c), the aspect of induced saltwater intrusion and
groundwater quality degradation in general was previously considered and discussed, albeit
indirectly (see issue discussion in Section 4.5.1.2.3).
As previously described, at the Turkey Point plant, large volumes of groundwater are pumped
from both the upper Biscayne and Upper Floridan aquifers for a variety of applications in
support of Turkey Point operations, as well as for other activities conducted on the Turkey Point
site unrelated to Units 3 and 4. These principal uses include withdrawals of brackish water from
the Upper Floridan aquifer for freshening of the CCS, operation of a recovery well system and
associated underground injection well to extract and dispose of hypersaline groundwater from
the Biscayne aquifer, operation of Biscayne aquifer marine wells that withdraw saltwater to
supplement CCS freshening, and operation of Upper Floridan aquifer site production wells for
various onsite uses (e.g., Unit 5 gas-fired power plant usage) (NRC 2019c).
The NRC staff’s analysis of potential groundwater use conflicts for SLR of Turkey Point first
considered the potential effects of site recovery well system and marine well operation on
existing groundwater quality. As described in the SEIS, the recovery well system is designed to
extract hypersaline groundwater radiating from the CCS. The permit for operation of the system
issued by the South Florida Water Management District requires the licensee to (1) mitigate
interference with existing legal uses of groundwater and (2) mitigate harm to natural resources.
The permit requires mitigation for harm including effects on surface water or groundwater that
result in lateral movement of the saltwater interface, reductions in the hydroperiod of wetlands
or natural waterbodies, causes the movement of contaminants contrary to water quality

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standards, or causes harm to the natural system including habitats for rare or endangered
species. In such cases, the licensee would be required to take corrective action. Based on the
NRC staff’s review of groundwater modeling performed by the licensee and State regulators, it
is likely that operation of the recovery well system will have beneficial water quality impacts by
retracting the CCS hypersaline plume and the westward expansion of the regional saltwater
interface, while providing reasonable assurance that any impacts on groundwater resources and
users would be mitigated.
The Turkey Point marine wells, completed in the Biscayne aquifer, had been used intermittently
since they were installed in 2015 to lower salinity in the CCS under abnormal conditions. As
detailed in the Turkey Point SLR SEIS, the NRC staff determined that periodic use of the marine
wells during the period of continued operations extending through the SLR term would not have
any substantial impact on groundwater quality or quantity. This is because the permeable
Biscayne aquifer in the affected area is recharged from Biscayne Bay, and any future marine
well operation on a temporary basis would be unlikely to substantially alter groundwater flow
beyond the affected area or result in any substantial drawdown in the Biscayne aquifer
(NRC 2019c).
Regarding continued operation of the Upper Floridan aquifer site production wells, the NRC staff
reviewed groundwater modeling commissioned by the licensee to support the 2014 site
certification modification approval process with the State of Florida. The licensee’s modified site
certification and conditions (issued in 2016) authorize a total average daily withdrawal of
28.06 Mgd (106,200 m3/day) from the Upper Floridan aquifer. As of 2018, groundwater
withdrawals from the Upper Floridan aquifer were less than the authorized amounts. As
documented in the Turkey Point SLR SEIS (NRC 2019c), groundwater modeling indicated that
operation of the freshening well system would be unlikely to result in any changes in regional
water quality because the Upper Floridan aquifer is already brackish, no saltwater interface
exists in the confined system, and water quality changes experienced by other aquifer users
have been minor. However, the SEIS noted that there is the potential for degradation of water
quality in wells producing from the Upper Floridan aquifer over time due to vertical seepage or
lateral movement of more saline water. Nevertheless, the licensee’s modified site certification
and associated conditions of certification for Turkey Point require the licensee to mitigate harm
to offsite groundwater users (either related to water quantity or quality) as well as to offsite
waterbodies, land uses, and other beneficial uses. In conclusion, the staff found that while
continued operation of the Upper Floridan aquifer production wells at the Turkey Point site,
including the freshening well system, would increase regional drawdown in the aquifer, the
effects would not be expected to affect water availability or impair the Upper Floridan aquifer as
a resource during the SLR term.
The issue of groundwater quality degradation from groundwater withdrawals for nuclear plants,
including induced saltwater intrusion, was designated as a Category 1 issue in the
2013 LR GEIS. The staff reviewed information from SEISs (for initial LRs and SLRs) completed
since development of the 2013 LR GEIS and identified no new information or situations that
would result in different impacts for this issue for either an initial LR or SLR term. Based on
these considerations, the NRC concludes that groundwater quality degradation resulting from
groundwater withdrawals would be SMALL for all nuclear plants during the initial LR and
SLR terms. This is a Category 1 issue.

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4.5.1.2.6

Groundwater Quality Degradation (Plants with Cooling Ponds)

This issue is a consolidation of two related issues in the 2013 LR GEIS: (1) groundwater quality
degradation (plants with cooling ponds in salt marshes) and (2) groundwater quality degradation
(plants with cooling ponds at inland sites). These two issues both consider the possibility of
groundwater quality and beneficial use (based on applicable water use classification) becoming
degraded as a result of the migration of contaminants discharged to cooling ponds. For this
reason, they are discussed here as a single issue.
Nuclear plants that use cooling ponds, impoundments, or similar structures as part of their
recirculating cooling water system discharge heated cooling water effluent back to the structure.
The effluent’s contaminant concentration increases relative to that of the makeup water as it
passes through the cooling system. These changes include increased total dissolved solids
(TDS) (because they concentrate as a result of evaporation), increased heavy metals (because
cooling water contacts the cooling system components), and increased chemical additives to
prevent biofouling.
Other relatively small volumes of wastewater are released from other plant systems depending
on the design of each nuclear plant. They are discharged from such sources as the service
water and auxiliary cooling systems, water treatment plant, laboratory and sampling wastes,
boiler blowdown, floor drains, stormwater runoff, and metal-treatment wastes. These waste
streams are discharged as separate point sources or are combined with the cooling water
discharges. While these discharges at operating nuclear power plants are normally addressed
in NPDES permits, upsets and bypasses of treatment systems along with spills and leaks of
wastewater and chemical substances can and do occur.
Because the ponds are generally unlined, the water discharged to them can interact with the
shallow groundwater system and may create a groundwater mound. In this case, groundwater
below the pond can flow radially outward, and this groundwater would have some of the
characteristics of the cooling system effluent.
In many coastal locations, including salt marshes, the groundwater is naturally brackish
(i.e., with a TDS concentration of about 1,000 to more than 10,000 milligrams per liter [mg/L])
and, thus, is already limited in its uses. As such, this issue primarily concerns the potential for
changing the groundwater use category of the underlying shallow and brackish groundwater
due to the introduction of cooling water contaminants. Two nuclear plants, the South Texas
plant in Texas and Turkey Point plant in Florida, have cooling systems (a human-made cooling
pond and CCS, respectively) located relatively near or constructed in salt marshes.
Plants relying on brackish water cooling systems would generally not be expected to further
degrade the quality of the shallow aquifer relative to its use classification. This is because
groundwater quality beneath salt marshes is already too poor for human use (i.e., it is
nonpotable water) and is only suitable for industrial use. Nuclear plants withdrawing from and
discharging cooling water to cooling ponds in salt marsh settings were expected to have a
SMALL impact on groundwater quality.
The NRC staff evaluated new information related to the impact of the continued operation of the
Turkey Point CCS on surface water and groundwater quality in the Turkey Point SLR SEIS in
the context of new, plant-specific analyses (NRC 2019c). As described in the SEIS, no surface
water is withdrawn to provide makeup water for the plant’s CCS. The plant’s intake and
discharge structures are located within the enclosed CCS, a cooling pond-like structure which

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does not directly discharge to the surface waters of Biscayne Bay. Instead, water in the CCS is
sustained by groundwater inflow from the underlying surficial aquifer (Biscayne aquifer) into
which the CCS was excavated. The Biscayne aquifer, in turn, is hydrologically connected to the
surrounding marsh land, mangrove areas, adjacent drainage canals, Biscayne Bay, and Card
Sound. The surficial groundwater underlying Turkey Point and CCS was classified by the State
of Florida in 1983 as Class G-III (nonpotable use) with TDS levels of 10,000 mg/L or greater,
while the Biscayne aquifer to the west side of the CCS was classified as Class G-II (potable
use). Information presented in the SEIS shows that the inland movement of seawater
(i.e., saltwater intrusion or encroachment) through the Biscayne aquifer (marked by the
saltwater interface) had already progressed inland and to the west of the location of the
Turkey Point site prior to construction of the CCS in the 1970s. As of 2017, the saltwater
interface was located about 4.7 mi (7.6 km) west of the CCS at its closest point and moving
west at a projected rate of 460 ft (140 m) per year. Nevertheless, through wells located inland of
the saltwater interface, the Biscayne aquifer is the major public water supply source across
Miami-Dade County as well as for the Florida Keys.
Due to a variety of environmental and other factors, the average salinity in the CCS increased
over time from that in nearby Biscayne Bay (approximately 34 practical salinity unit [PSU]) to
approximately 90 PSU in 2014 and 2015 and became hypersaline (i.e., saltier than seawater).
When the NRC staff prepared the Turkey Point initial LR SEIS in 2002 (NRC 2002a), the staff
acknowledged the existence of a hypersaline plume in the Biscayne aquifer directly beneath the
CCS. What was not fully understood at the time was the potential for the hypersaline plume to
migrate vertically downward through the Biscayne aquifer and then to move laterally within the
Biscayne aquifer beyond the CCS boundaries. Over the operational life of the CCS, the size of
the hypersaline plume grew larger. By 2018, the maximum extent of the hypersaline plume was
approximately 3 mi (4.8 km) west of the CCS in the intermediate zone of the Biscayne aquifer
and also to the east beneath Biscayne Bay and Card Sound. At the direction of the Florida
Department of Environmental Protection, groundwater modeling performed by the licensee
indicated that operating the CCS with salinity in excess of 35 PSU was the single largest
contributor to changes (movement) in the location of the saltwater interface (NRC 2019c).
In general, the results of extensive groundwater monitoring conducted by the licensee under the
direction of State of Florida and Miami-Dade County have shown that the extent of “potential
CCS influence” is 4.5 mi (7.2 km) west of the CCS as measured at the base (deep interval) of
the Biscayne aquifer. At this distance, and as detailed in the SEIS, the composition of the
groundwater includes ambient saline water mixed with small quantities of CCS water (including
soluble salts, nutrients, and tritium), whereas the degree of CCS influence (marked by higher
chloride and tritium concentrations) increases closer to the CCS. Further, elevated tritium levels
in the intermediate and deep monitored portions of the aquifer also indicate the potential
influence of CCS water in groundwater to the east of the CCS beneath Biscayne Bay. At no
location outside the boundary of the Turkey Point site did tritium levels in groundwater approach
the EPA and State primary drinking water standard for tritium (20,000 picocuries per liter [pCi/L])
(40 CFR Part 141), while the highest tritium levels observed in offsite monitoring wells near the
site during the 2018 reporting period were approximately 15 percent of the standard. Further,
the monitoring showed that no CCS-sourced constituents had affected the overlying surface
water quality (NRC 2019c).
In accordance with the regulatory agreements reached with and requirements imposed by the
Florida Department of Environmental Protection and Miami-Dade County, the licensee
implemented a salinity management plan and has undertaken other measures to abate
hypersaline water discharges and to actively remediate the hypersaline groundwater west and

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north of the CCS. In 2016, the licensee also instituted pumping of brackish groundwater into the
CCS for salinity management purposes and specifically to maintain the average annual salinity
of the CCS at or below 34 PSU (see issue discussion Section 4.5.1.2.3). In 2017, the licensee
commenced operation of a recovery well system to extract hypersaline groundwater from near
the base of the Biscayne aquifer and to limit the operational influence of the plant’s CCS. As
described in the SEIS, it was projected that operation of the recovery well system would achieve
retraction of the hypersaline plume back to within the Turkey Point site boundaries within
10 years (i.e., by about 2028) (NRC 2019c).
Regarding surface water quality impacts, the NRC staff concluded that the impacts on adjacent
surface waterbodies via the groundwater pathway from continued CCS operations were SMALL
and projected to remain SMALL during the SLR term. With respect to groundwater, the staff
found that hypersaline groundwater containing tritium had migrated beyond the boundaries of
the CCS and Turkey Point property at the base of the Biscayne aquifer from Class G-III
groundwater (i.e., nonpotable groundwater) to the west and to the east beneath Biscayne Bay.
The hypersaline groundwater plume was also a significant contributor to the westward migration
of the saltwater interface and would remain so without mitigation. The staff further determined
that based on the data evaluated in the SEIS, CCS-influenced water had migrated into portions
of the Biscayne aquifer that are a potential source of potable water. These aspects of cooling
pond operations and their effects on groundwater quality were not considered in the 1996 or
2013 LR GEIS, and thus represented new and significant information compared to the
2013 LR GEIS. As a result, the NRC staff concluded that the plant-specific impacts for this issue
at Turkey Point were MODERATE for operations during the initial LR term but were projected to
be SMALL during the SLR term as a result of ongoing remediation measures and State and
county regulatory oversight (NRC 2019c).
For the South Texas plant initial LR, the NRC staff considered potential groundwater quality
impacts from operation of the plant’s main cooling reservoir (MCR), a 7,000 ac (2,833 ha)
engineered impoundment enclosed by a 12.4 mi (20 km) embankment. It is unlined and is the
source of the plant’s condenser cooling water and receives various wastewater effluents,
regulated under a Texas Pollutant Discharge Elimination System permit. As described in the
SEIS, the MCR is a local source of recharge for the Upper Shallow Chicot aquifer (NRC 2013b).
The unlined MCR acts as a local recharge source for the Upper Shallow Chicot aquifer. Further,
a substantial portion of the seepage through the MCR is collected by the 770 relief wells that
surround the MCR, which discharge the seepage water to a perimeter drainage system and
then to local drainages (NRC 2013b). Therefore, locally, relative to the South Texas site, the
MCR influences the groundwater quality of the Upper Shallow Chicot aquifer and potentially
local surface water quality.
The NRC staff’s analysis found that seepage from the MCR to the Upper Shallow aquifer would
initially have the same TDS concentration as the MCR (i.e., median concentration of about
2,000 mg/L). The staff also noted that for radionuclides the impact on water quality would be
bounded by the maximum observed ambient concentration of tritium in the MCR (i.e., 17,410 in
1996 and levels less than 14,000 pCi/L thereafter). Groundwater monitoring showed that tritium
levels in the Shallow Chicot aquifer around the MCR remained below the EPA drinking water
standard of 20,000 pCi/L (40 CFR Part 141), with a maximum concentration of 8,600 pCi/L in
2012. As also discussed in the SEIS, relief wells had measured tritium concentrations of less
than 7,000 pCi/L at the time of the staff’s review (NRC 2013b).

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The Shallow Chicot aquifer exhibits poor water quality and low productivity, with TDS
concentrations in the local groundwater exceeding the EPA secondary drinking water standard
of 500 mg/L (40 CFR Part 143) and averaging 1,200 mg/L. The shallow aquifer has been used
in the vicinity of the South Texas plant for livestock watering. In contrast, water drawn from the
Deep Chicot aquifer is of higher quality. The licensee’s five onsite supply wells draw from the
deep aquifer, as do public supply wells for the nearby communities to the east of the plant site
(NRC 2013b).
In summary, for the South Texas plant initial LR, the NRC staff found that seepage from the
MCR and other onsite contaminant releases had not substantially affected the groundwater
quality within the plant site and impacts on groundwater quality offsite would be less. TDS levels
were consistent with the existing groundwater quality and its past and potential future use as a
source of water for livestock. Any impacts on groundwater quality would be localized because
the groundwater plumes originating from the MCR are local to the plant site and the region
immediately downgradient of the site to the lower Colorado River. Thus, the staff concluded that
groundwater quality impacts from MCR seepage and other contaminant releases to
groundwater from South Texas operations would remain SMALL during the license renewal
term (NRC 2013b).
Some nuclear power plants that rely on unlined cooling ponds are located at inland sites
surrounded by farmland or forest or undeveloped open land. Degraded groundwater has the
potential to flow radially from the ponds and reach offsite groundwater wells. The degree to
which this occurs depends on the water quality of the cooling pond; site hydrogeologic
conditions (including the interaction of surface water and groundwater); and the location, depth,
and pump rate of water wells. Mitigation of significant problems stemming from this issue could
include lining existing ponds, constructing new lined ponds, or installing subsurface flow barrier
walls. At either coastal (salt marsh) sites as discussed above or inland sites, groundwater
monitoring networks would be necessary to detect and evaluate groundwater quality
degradation.
The degradation of groundwater quality associated with cooling ponds had not been reported for
any inland nuclear plant sites at the time the 2013 LR GEIS was prepared.
In addition to the Turkey Point and South Texas plants, as evaluated above, the other operating
nuclear plants with cooling ponds as identified in Section 3.1.3 are Dresden Nuclear Power
Station (Dresden), Robinson, Virgil C. Summer Nuclear Station (Summer), and Wolf Creek
Generating Station (Wolf Creek). Since publication of the 2013 LR GEIS, the NRC has
performed license renewal environmental reviews for two nuclear power plants with cooling
ponds at inland sites (Braidwood and LaSalle).
As contained in the Braidwood initial LR SEIS, the NRC notes that the plant’s cooling pond
(constructed from a former strip coal mine) was built with a slurry wall to isolate the pond from
the Upper aquifer. As a result, no movement of water between the aquifer and cooling pond
would be expected, and the bottom of the cooling pond is filled with low-permeability shale, clay,
and siltstone mine spoils. Much of the cooling pond is accessible to the public for fishing and
other recreational activities. Wastewater discharges from the pond (i.e., blowdown) to the
Kankakee River are regulated under an Illinois-issued NPDES permit. The NRC staff concluded
that the impact of the cooling pond on groundwater quality would be SMALL during the license
renewal term (NRC 2015d).

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In the LaSalle initial LR SEIS (NRC 2016d), the staff described the plant’s cooling pond as being
formed from the construction of earthen dikes to enclose the north, east, and south sides of the
pond; a natural levee created by existing topography forms the fourth side. Engineered fill
consisting of silty-clay, taken from borrow areas within the pond basin, was used in the
construction of the dikes. A perimeter drainage ditch designed to intercept runoff and to capture
and direct seepage toward surface drainages and away from the dikes flanks the pond’s dikes.
The staff found that seepage from the cooling pond is negligible because the pond was built on
the Glacial Drift Aquitard (Wedron Silty-Clay Till), a geologic unit with very low permeability. The
pond’s ambient water quality has also supported a recreational fishery. Between 2009 and
2014, with the exception of a few tritium samples that were near background values, no
radionuclides have been detected in the pond above background values. Cooling pond
blowdown is discharged to the Illinois River in accordance with an Illinois-issued NPDES permit.
For these reasons, the NRC staff concluded that that the impact of operation of LaSalle’s
cooling pond on groundwater quality would be SMALL during the license renewal term
(NRC 2016d).
The staff reviewed information from SEISs (for initial LRs and SLRs) completed since
development of the 2013 LR GEIS. Based on the information reviewed and the preceding
discussion, the NRC concludes that groundwater quality degradation for nuclear plants using
cooling ponds in either coastal (salt marsh) settings or at inland sites could be greater than
SMALL (i.e., SMALL or MODERATE) depending on site-specific differences in the cooling
pond’s construction and operation; water quality; site hydrogeologic conditions (including the
interaction of surface water and groundwater); and the location, depth, and pump rate of any
water supply wells contributing to or affected by outflow or seepage from a cooling pond.
Therefore, this revised, consolidated issue is a Category 2 issue.
4.5.1.2.7

Radionuclides Released to Groundwater

As described in the 2013 LR GEIS, this Category 2 issue was added to evaluate the potential
contamination of groundwater from the inadvertent (abnormal) release of liquids containing
radioactive material from nuclear power plant systems into the environment.
The issue remains relevant to license renewal because all commercial nuclear power plants
routinely release radioactive gaseous and/or liquid materials into the environment. These
radioactive releases are designed to be planned, monitored, documented, and released into the
environment at designated discharge points. However, numerous events at power reactor sites
have involved unknown, uncontrolled, and unmonitored releases of liquids containing
radioactive material into the environment and have affected soil and/or groundwater. NRC
regulations in 10 CFR Part 20 and in 10 CFR Part 50 limit the amount of radioactive material
from all sources at a nuclear power plant released into the environment to levels that are as low
as is reasonably achievable (ALARA), along with associated radiation dose limits. The
regulations are designed to protect the public and the environment.
The majority of the inadvertent liquid release events have involved tritium, which is a radioactive
isotope of hydrogen. However, other radioactive isotopes, such as cesium and strontium, have
also been inadvertently released into the groundwater. The types of events have included, but
have not been limited to, leakage from spent fuel pools (SFPs), storage tanks, buried piping,
failed pressure relief valves on an effluent discharge line, and other nuclear power plant
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As summarized in Section 3.5.2.2 of this LR GEIS, in 2006, the NRC’s Executive Director for
Operations chartered a task force to conduct a lessons learned review of these incidents. On
September 1, 2006, the task force issued its report: Liquid Radioactive Release Lessons
Learned Task Force Report (NRC 2006e).
The most significant conclusion dealt with the potential health impacts on the public from the
inadvertent releases. Although there were numerous events where radioactive liquid was
released to the groundwater in an unplanned, uncontrolled, and unmonitored fashion, based on
the data available, the task force did not identify any instances where public health and safety
was adversely affected.
Specific examples from NRC (2006e), as discussed in the 2013 LR GEIS, focused on tritium
releases at 15 operating plants. Concentrations of tritium in sampled onsite groundwater at
many of these plants ranged well above the EPA drinking water standard of 20,000 pCi/L
(40 CFR Part 141). Examples include onsite monitoring well samples of up to 250,000 pCi/L at
the Braidwood plant in Illinois, up to 211,000 pCi/L at the Indian Point plant in New York, up to
486,000 pCi/L at the Dresden plant in Illinois, more than 30,000 pCi/L at the Watts Bar Nuclear
Plant (Watts Bar) in Tennessee, and 71,400 pCi/L at the Palo Verde Nuclear Generating Station
(Palo Verde) in Arizona. Examples of samples taken either directly from the source of the leak
or from nearby onsite monitoring wells included samples with up to 200,000 pCi/L of tritium at
the Callaway plant in Missouri, up to 15,000,000 pCi/L at the Salem Nuclear Generating Station
(Salem) in New Jersey, and up to 750,000 pCi/L at the Seabrook Station (Seabrook) in New
Hampshire. At the Byron plant in Illinois, tritium in monitoring wells was above the background
level but below drinking water standards (up to 3,800 pCi/L). The location and construction of
the monitoring wells relative to potential leak locations had not been evaluated. For each
example, it is possible that a different well placement could detect higher or lower activity
concentrations.
Other reported instances (NRC 2006e) of tritium above background levels have been a result of
operator error, licensed discharge, or leaks or discharges to drain systems. At the Oyster Creek
plant in New Jersey (which permanently shut down in September 2018), a mistake involving a
valve allowed tritium-contaminated water to flow into the discharge canal. Sampling of this water
showed levels of 16,000 pCi/L. At the Wolf Creek plant in Kansas, an onsite lake receiving liquid
effluent was found to have a tritium activity concentration of 13,000 pCi/L. The Perry Nuclear
Power Plant (Perry) in Ohio had water samples in its drainage system with an activity
concentration of 60,000 pCi/L. In each of these cases, the tritium present at the surface could
infiltrate or seep into the groundwater system.
The NRC task force did not find the referenced tritium releases to be a health risk to the public
or onsite workers (NRC 2006e). In the cited instances the tritiated groundwater was expected to
remain onsite. However, one identified exception was an event at the Braidwood plant, which
resulted in detectable concentrations of tritium at an offsite location. Sampling of an offsite
residential well at Braidwood showed 1,600 pCi/L of tritium, a level that was above the
background level but well below the EPA drinking water standard. Additionally, there would be
no potential for risk to workers unless onsite wells were used for the potable water system and if
the leak was in the capture zone of the well. However, the NRC requires that the onsite potable
well water be monitored for radioactivity to protect plant workers.

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The task force identified that under current NRC regulations the potential exists for unplanned,
uncontrolled, and unmonitored releases of radioactive liquids to migrate offsite into the public
domain. The following elements collectively contribute to this conclusion:
• Some of the power plant components that contain radioactive fluids that have leaked were
constructed to commercial standards, in contrast to plant safety systems that are typically
fabricated to more stringent requirements. The result is a lower level of assurance that these
types of components will be leak-proof over the life of the plant.
• Some of the components that have leaked were not required by NRC regulations to be
subject to surveillance, maintenance, or inspection activities by the licensee. This increases
the likelihood that leakage in such components can go undetected. Additionally, relatively low
leakage rates may not be detected by plant operators, even over an extended period of time.
• Portions of some components or structures are physically not visible to operators, thereby
reducing the likelihood that leakage will be identified. Examples of such components include
buried pipes and SFPs.
• Leakage that enters the ground below the plant may be undetected because there are
generally no NRC requirements to monitor the groundwater onsite for radioactive
contamination unless an onsite well is used for drinking water or irrigation.
• Contamination in groundwater onsite may migrate offsite undetected. Although the power
plant operator is required by NRC regulations to perform offsite environmental monitoring, the
sampling locations are typically in the vicinity of the routine effluent discharge point into the
environment, not around plant systems, piping, and tanks containing radioactive liquids.
Another aspect encountered by the NRC due to the inadvertent releases was the high level of
concern from the public, even at the very low radiation levels caused by the events. There has
also been significant media coverage and demands by State and local government officials and
members of Congress for the NRC to take action to stop these events.
The NRC has continued its oversight and evaluation of inadvertent releases of liquids containing
radioactive material from nuclear power plants, particularly those that result in groundwater
contamination. A discussion of NRC staff and Commission engagement and actions on this
issue since 2006 is presented in Section 3.5.2.2.
The NRC has also considered the impact of the inadvertent release of radioactive liquids during
its environmental reviews performed for initial LR and SLR applications since 2013. The
following narrative discusses noteworthy findings from these reviews.
As described in the Seabrook initial LR SEIS, the NRC evaluated the impact of historical
inadvertent releases of radionuclides on groundwater resources. The releases originated from
the cask loading area and transfer canal, which is connected to the plant’s SFP. Before repairs
were completed in 2004, tritium concentrations in the primary auxiliary building were reported at
up to 84,000 pCi/L in 2000 and, in the Unit 1 containment enclosure ventilation area,
concentrations were reported up to 3,560,000 pCi/L in 2003. As part of the licensee’s corrective
actions, a groundwater dewatering and pumping system was installed to provide hydraulic
containment of contaminated groundwater, and an extensive groundwater monitoring network
was also installed. By 2011, tritium concentrations in the containment enclosure ventilation area
had dropped substantially, and ranged from 2,150 to 50,000 pCi/L. By the end of 2011, the
highest detection of tritium in the shallow aquifer at the site was 2,850 pCi/L in a well located
near the Unit 1 containment structure. The NRC determined that inadvertent releases of tritium

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had not substantially impaired site groundwater quality or affected groundwater use
downgradient of the Seabrook plant. The NRC further concluded that groundwater quality
impacts would remain SMALL during the license renewal term (NRC 2015b).
There is a long history of documented spills and leaks of liquids containing radioactive material
at the Indian Point site in New York (Units 2 and 3 permanently shut down on April 30, 2020 and
April 30, 2021, respectively). The NRC, in the second supplement to the SEIS for the initial LR
of the Indian Point plant (NRC 2018e), evaluated the environmental impact of inadvertent
releases to site groundwater, along with actions taken by the licensee, the NRC, and State
regulators to assess contamination and to take corrective action. As detailed in the SEIS,
groundwater contamination across the site has primarily been traced to the Unit 1 and Unit 2
SFPs. Historically, leaks from the Unit 1 SFP created contaminant plumes consisting of
strontium-90 and tritium, and leaks from various sources associated with Unit 2 created another
plume of tritium. These plumes were found to comingle with each other and extend to the
Hudson River. Over much of the site, the plumes occur under buildings and other plant
structures. Before they reach the Hudson River, all three plumes are confined to the site and
both vertically and laterally to the Inwood Marble. Other radionuclides have been sporadically
identified in the groundwater at discrete locations onsite.
Since 2005, the licensee has maintained an extensive long-term groundwater monitoring
program designed in part to characterize the current and potential future offsite groundwater
contaminant migration to the Hudson River. Based on the data presented in the SEIS,
concentrations of several radionuclides (e.g., tritium, strontium-90, cesium-137) in groundwater
exceeded the EPA drinking water standard (i.e., yielding an equivalent annual dose of 4 mrem).
In February 2016, the licensee notified the NRC of a significant increase in groundwater tritium
levels in monitoring wells located near the Unit 2 fuel storage building. Tritium concentrations in
one well increased from 18,900 pCi/L to 8.97 million pCi/L. Investigations and inspection by the
licensee, the NRC, and State followed. The sources of the spills were identified. As a follow-up
action, the NRC on January 17, 2017, issued a notice of violation with a finding of very low
safety significance under 10 CFR 20.1406(c) for failure by the licensee to conduct operations to
minimize the introduction of residual radioactivity into the site, including the subsurface. The
NRC’s environmental review determined that site groundwater contamination will either remain
onsite or be discharged into the Hudson River. Offsite groundwater supplies should continue to
be unaffected by ongoing operations. However, the NRC concluded that the impact on onsite
groundwater quality was MODERATE and likely to remain MODERATE through the end of
scheduled plant operations (i.e., by no later than April 30, 2025, for Unit 3). However, with the
elimination of radionuclide leaks to the groundwater and with the use of monitored natural
attenuation, the impact on onsite groundwater quality could move to SMALL. The NRC also
concluded that the impact of site groundwater contamination on surface water quality was
SMALL, because the concentrations of radionuclides in groundwater discharging to the Hudson
River should be rapidly diluted to low levels (NRC 2018e).
A number of inadvertent releases of radionuclides to groundwater have been documented at the
River Bend plant over the period 2008–2015, as described in the initial LR SEIS (NRC 2018c).
These releases resulted in the NRC issuing the licensee a non-cited violation of 10 CFR
20.1406(c) in 2016 for failure to conduct operations to minimize the introduction of residual
radioactivity into the site. The licensee took corrective actions to remedy and prevent future
leaks from the turbine building in the power block, including pumping groundwater from areas
near the power block. However, as documented in the SEIS, tritium exists in site groundwater in
a small area within the power block area, including groundwater within the structural fill and in
the underlying Upland Terrace aquifer. Monitoring wells are installed at various depths within

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the structural fill and the Upland Terrace aquifer. The direction of groundwater flow in the
structural fill and the Upland Terrace aquifer is southwestward toward the Mississippi River
aquifer and from there into the Mississippi River. In 2017, tritium concentrations in the structural
fill of the power block and in the underlying Upland Terrace aquifer were 740,000 pCi/L and
223,000 pCi/L, respectively. Meanwhile, a short distance away from the power block, tritium
concentrations were much lower, with a maximum value of 54,900 pCi/L. The NRC staff
concluded that the impact of radionuclides released to groundwater at River Bend during the
license renewal term could range from SMALL to MODERATE (i.e., if the licensee has not
identified and stopped all leak sources, and if tritium continued to leak into site groundwater)
(NRC 2018c).
In the Peach Bottom SLR SEIS, the NRC evaluated the history of inadvertent releases of
radionuclides at the site and corrective actions taken by the licensee since 2006. While the
licensee had recorded no inadvertent releases between 2011 and 2014, a release in April 2015
was traced to floor drains in the Unit 3 turbine building moisture separator area. The highest
tritium level observed in a nearby overburden well was 38,100 pCi/L. As described in the SEIS,
a plume of tritium-contaminated groundwater remained in the overburden material beneath the
plant site. The plume resulted from previous inadvertent spills and leaks of radionuclidecontaining liquids from the plant. The plume was determined to extend northeast of the Unit 3
turbine building toward the Peach Bottom intake basins. The NRC found that inadvertent
releases of radionuclides (primarily tritium) had not substantially impaired or noticeably altered
groundwater quality with respect to drinking water standards within the overburden and bedrock
groundwater beneath the plant site. Onsite inadvertent releases had no measurable effect on
surface waters adjoining the site, and did not threaten offsite groundwater. The NRC concluded
that impacts on groundwater resources from inadvertent releases of radionuclides were SMALL
and projected to remain SMALL during the SLR term (NRC 2020g).
The staff reviewed information from SEISs (for initial LRs and SLRs) completed since
development of the 2013 LR GEIS. Based on the information reviewed and cited regarding
inadvertent releases at operating nuclear power plants, the NRC concludes that the impact on
groundwater quality from the inadvertent release of radionuclides could be SMALL or
MODERATE during the initial LR and SLR terms, depending on such factors as the magnitude
of the leak or spill, radionuclides involved and concentrations, hydrogeologic factors, the
distance to receptors, and the response time of plant personnel to identify and stop the leak in a
timely fashion. The NRC staff will consider whether the release has caused or could cause
substantial impairment or noticeable alteration of groundwater quality in an aquifer with respect
to designated use classification or applicable drinking water or other applicable standards.
Therefore, this is a Category 2 issue.

4.6
4.6.1

Ecological Resources
Environmental Consequences of the Proposed Action – Continued Operations
and Refurbishment Activities

Environmental conditions at operating nuclear power plants have been well established during
the current licensing term. Continued operations are not expected to change substantially during
the license renewal term, and therefore, existing conditions are expected to persist during
initial LR and SLR terms. Initial LR or SLR generally represent a continuation of current
environmental stressors that have existed during many years of operation. License renewal is
unlikely to introduce wholly new stressors on the ecological environment. However, due to the
ever-changing nature of ecological communities, the magnitude of impact that these stressors

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exhibit on ecological resources may change. Sections 3.6.1, 3.6.2, and 3.6.3 discuss terrestrial
resources, aquatic resources, and federally protected ecological resources, respectively, and
existing environmental stressors. The following sections present the potential effects on these
resources associated with continued operations of a nuclear power plant during a license
renewal term.
4.6.1.1

Terrestrial Resources

Continued operations of nuclear power plants during an initial LR or SLR term are expected to
include continued operation of the cooling water intake system (e.g., once-through system,
cooling pond, or cooling tower[s]), continued management of in-scope transmission lines and
associated ROWs, maintenance of site facilities, releases of gaseous and liquid effluents, and
ground disturbances and other effects associated with refurbishment, if applicable.
Terrestrial plants and animals would continue to be exposed to chemical and radionuclide
releases and cooling tower drift (at sites with cooling towers). Continued site and transmission
line maintenance could affect vegetation and disturb wildlife. Nuclear power plant structures and
transmission lines would continue to pose collision hazards for birds. Wildlife near the site would
experience elevated noise, vibration, and general human disturbance. Habitat loss, degradation,
disturbance, or fragmentation could result from construction, refurbishment, or other site
activities, including site maintenance and infrastructure repairs. Plants and animals would also
be exposed to electromagnetic fields (EMFs). Section 3.6.1 discusses the basis for these
factors; this section evaluates how these factors would affect terrestrial resources during the
course of a license renewal term.
This section considers the effects that terrestrial resources may experience as a result of
initial LR or SLR as eight issues. These issues are:
• non-cooling system impacts on terrestrial resources2
• exposure of terrestrial organisms to radionuclides
• cooling system impacts on terrestrial resources (plants with once-through cooling systems or
cooling ponds)
• cooling tower impacts on terrestrial plants2
• bird collisions with plant structures and transmission lines
• water use conflicts with terrestrial resources (plants with cooling ponds or cooling towers
using makeup water from a river)
• transmission line right-of-way (ROW) management impacts on terrestrial resources
• electromagnetic field effects on terrestrial plants and animals2

2

Issue retitled from the 2013 LR GEIS for clarity and consistency with other ecological resource issues.
No substantive changes to this issue have been made.

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4.6.1.1.1

Non-Cooling System Impacts on Terrestrial Resources

This issue concerns the effects of nuclear power plant operations on terrestrial resources during
an initial LR or SLR term that are unrelated to operation of the cooling system. Such activities
include landscape and grounds maintenance, stormwater management, elevated noise levels
and vibration, and ground-disturbing activities. These impacts are expected to be like past and
ongoing impacts that terrestrial resources are already experiencing at the nuclear power
plant site.
In the 1996 LR GEIS, the NRC evaluated the impacts of refurbishment on terrestrial resources.
In the 2013 LR GEIS, the NRC expanded this issue to include impacts of other site activities,
unrelated to cooling system operation, that may affect terrestrial resources. In both the 1996
and 2013 LR GEISs, the NRC concluded that effects could be SMALL, MODERATE, or LARGE.
Therefore, these were considered Category 2 issues for all nuclear power plants. This LR GEIS
refines the title of this issue from “Effects on terrestrial resources (non-cooling system impacts)”
to “Non-cooling system impacts on terrestrial resources” for clarity and consistency with other
ecological resource LR GEIS issue titles.
Industrial-use portions of nuclear power plant sites are typically maintained as modified habitats
with lawns and other landscaped areas; however, these areas may also include disturbed early
successional habitats or small areas of relatively undisturbed habitat. Developed areas are
generally maintained through physical (e.g., mowing and cutting) and chemical (e.g., herbicides
or pesticides) means. Plant diversity in these areas is generally low and often consists of
cultivated varieties or weedy species tolerant of disturbance. Nonindustrial-use portions of
nuclear power plant sites may include natural areas, such as forests, shrublands, prairies,
riparian areas, or wetlands. These habitats may be undisturbed or in various degrees of
disturbance.
Certain areas may also be managed to preserve natural resources, either privately by the
nuclear power plant operator or in conjunction with local, State, or Federal agencies. For
instance, approximately 13,000 ac (5.300 ha) of land to the south and west of the Turkey Point
site in Florida is part of the Everglades Mitigation Bank (NRC 2019c). Under the guidance of
Federal and State agencies, Florida Power and Light Company creates, restores, and enhances
this habitat to provide compensatory mitigation of wetland losses elsewhere. At Shearon Harris
Nuclear Power Plant (Harris) in North Carolina, Duke Energy leases land, including part of
Harris Lake, to Wake County which co-manages the area with the North Carolina Wildlife
Resources Commission for natural resource preservation and recreational opportunities (Duke
Energy 2017). Continued conservation efforts during the license renewal term would have
beneficial effects on the local ecology.
The characteristics of terrestrial vegetation and wildlife communities on nuclear power plant
sites have generally developed in response to many years of plant operations and maintenance.
While some communities may have reached a relatively stable condition, some may have
continued to change gradually over time. Operations and maintenance activities as well as any
refurbishment during the license renewal term are expected to be like current activities (see
Section 2.1). Because the plants and animals present on nuclear power plant sites are generally
tolerant of disturbance and acclimated to human activity, continued operations during the
license renewal term would not affect the composition of terrestrial communities or any current
trends of change.

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Continued site landscape maintenance would maintain vegetation on developed portions of
nuclear power plant sites as low-diversity habitat. Wildlife diversity immediately surrounding
industrial-use portions of sites and within other landscaped areas is typically limited by
low-quality habitat and generally includes species adapted to developed land uses. Animals in
these areas may be exposed to elevated noise levels and vibration associated with
transformers, cooling towers, and other site activities that could cause animals to avoid suitable
habitat or otherwise disrupt behavioral patterns.
Stormwater management may affect onsite and adjacent wetlands. Effects may include
changes in plant community characteristics, altered hydrology, decreased water quality, and
sedimentation (EPA 1993, EPA 1996; Wright et al. 2006). Impervious surfaces within the
watershed generally result in increased runoff and reduced infiltration, which can cause
changes in the frequency or duration of inundation or soil saturation and greater fluctuations in
wetland water levels. Runoff may contain sediments, contaminants from road and parking
surfaces, or herbicides. Erosion of wetland substrates and plants can result from increased flow
from impervious surfaces.
If activities associated with continued nuclear power plant operations disturb nonindustrial-use
portions of sites, some wildlife could be displaced to nearby available habitats, and competition
could increase among species. Terrestrial plants and animals could experience adverse effects
from fugitive dust, altered surface water flow patterns, water quality degradation, introduction or
proliferation of non-native and invasive species, and general disturbance from human activity.
Species that are more sensitive to disturbance may be displaced by more tolerant species.
Impervious surfaces within watersheds generally result in more runoff and less infiltration to
shallow groundwater, which alters the hydrologic input to nearby wetlands (EPA 1993,
EPA 1996; Wright et al. 2006). This can change the frequency or duration of inundation or soil
saturation, cause greater fluctuations in wetland water levels, and degrade or erode wetland
substrates. Site runoff often contains sediments, contaminants from road and parking surfaces,
or herbicides (EPA 1993, EPA 1996; Wright et al. 2006). In rare or unique plant communities,
sensitive habitats such as wetlands, bird rookeries, or high-quality undisturbed habitats occur in
or near affected areas; impacts on such resources could be considered MODERATE or LARGE
if they would noticeably alter or destabilize important attributes of those resources. Impacts
would be considered SMALL if only previously disturbed or other lower-quality habitats would be
affected and no noticeable or detectable impacts on the ecological environment would result.
The 2013 LR GEIS indicates that elevated noise levels and vibration from transformers and
cooling towers could disrupt wildlife behavioral patterns or cause animals to avoid such areas.
However, limited wildlife inhabit most areas of nuclear power plant sites that experience
elevated noise levels due to the developed, industrial nature of the site, regular presence of
human activity, and associated lack of high-quality habitat. Wildlife that does occur in developed
areas has already adapted to the conditions of the plant site and is tolerant of disturbance. The
NRC staff have not identified noise or vibration associated with normal nuclear power plant
operations to be of concern in any SEISs (initial LR or SLR) completed since development of
the 2013 LR GEIS. Therefore, continued noise associated with the operation of transformers
and cooling towers during the license renewal term is unlikely to create noticeable impacts on
terrestrial resources.

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In the 1996 and 2013 LR GEISs, the NRC staff anticipated that nuclear power plants may
require refurbishment to support continued operations during a license renewal term (see
Section 2.1.2). However, refurbishment has not typically been necessary for license renewal.
Only two nuclear power plants have undertaken refurbishment as part of license renewal
(Beaver Valley Power Station [Beaver Valley] and Three Mile Island, Unit 1 [Three Mile Island;
no longer operating], both of which are located in Pennsylvania) (NRC 2009a; NRC 2009b). In
addition to refurbishment, license renewal could also require construction of additional onsite
spent fuel storage. Refurbishment or spent fuel storage construction could require new parking
areas for workers as well as new access roads, buildings, and facilities. Temporary project
support areas for equipment storage, overflow parking, and material laydown areas could also
be required.
Any activities that require construction or involve ground disturbance could affect terrestrial
habitats. Ground-disturbing activities may be related to refurbishment or other planned activities
during the license renewal term that involve demolition or construction. Natural habitats could be
destroyed or altered and wildlife could be displaced or killed. Indirect effects include erosion and
sedimentation, both of which are typically proportional to the amount of surface disturbance,
slope of the disturbed land, and condition of the area at the time of disturbance. Chemical
contamination could also occur from fuel or lubricant spills. Temporarily disturbed habitats would
likely recover over time, while permanently disturbed habitats would be permanently lost.
Associated noise, vibration, and human activity could cause wildlife to temporarily avoid the
affected area or otherwise alter behaviors.
Some activities during a license renewal period could require Federal permits or review, which
would mitigate potential effects. For instance, site activities involving the discharge of dredge or
fill material into wetlands would likely require the nuclear power plant operator to obtain a CWA
Section 404 (33 U.S.C. § 1251 et seq.) permit from the USACE. Actions that may affect
federally endangered or threatened species or other federally protected resources would require
interagency consultation with the FWS or the National Oceanic and Atmospheric Administration
(NOAA). Some states and local jurisdictions also require permits for actions that may affect
State-listed species and rare habitats. Such permits would ensure that effects on sensitive
habitats and species are minimized during the license renewal term.
Many nuclear power plant operators have developed site or fleet-wide environmental review
procedures that help workers identify and avoid impacts on the ecological environment when
performing site activities. These procedures generally include checklists to help identify potential
effects and required permits and BMPs to minimize the affected area. BMPs relevant to
terrestrial resources may include measures to control fugitive dust, runoff, and erosion from
project sites; minimize the spread of nuisance and invasive species; and reduce wildlife
disturbance. Proper implementation of environmental procedures and BMPs would minimize or
mitigate potential effects on terrestrial resources during the license renewal term.
Some utilities are members of the Wildlife Habitat Council, which helps corporations manage
their land for broad-based biodiversity enhancement and conservation. As part of membership,
sites develop wildlife management plans that include a comprehensive strategy for enhancing
and conserving site ecological resources. For instance, at the Limerick plant in Pennsylvania,
Exelon places and monitors artificial avian nesting structures and bat roost boxes (NRC 2014d).
At the Peach Bottom plant in Pennsylvania, Exelon has established a butterfly garden to support
and promote native pollinator diversity (Exelon 2011). To maintain membership, sites must
undertake projects that promote native biodiversity, gather data on conservation efforts, and
report on their progress. Other nuclear power plant sites that maintain Wildlife Habitat Council

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membership include Braidwood, Byron Station (Byron), Calvert Cliffs, Clinton Power Station
(Clinton), Dresden, James A. FitzPatrick Nuclear Power Plant (Fitzpatrick), R.E. Ginna Nuclear
Power Plant (Ginna), LaSalle, Nine Mile Point Nuclear Station (Nine Mile Point), and Quad
Cities Nuclear Power Station (Quad Cities). Continued participation in this or similar
environmental conservation organizations would minimize or mitigate potential effects on
terrestrial resources during the license renewal term.
The staff reviewed information from SEISs (for initial LRs and SLRs) completed since
development of the 2013 LR GEIS. In summary, the potential non-cooling system effects during
an initial LR or SLR term depend on numerous site-specific factors, including the ecological
setting of the plant; the planned activities during the license renewal period; the characteristics
of the plants and animals present in the area (e.g., life history, distribution, population trends,
management objectives, etc.); and the implementation of BMPs or other conservation initiatives.
Non-cooling system impacts would be SMALL at most nuclear power plants but may be
MODERATE or LARGE at some plants. Therefore, a generic determination of potential impacts
on terrestrial resources from continued operations during a license renewal term is not possible.
The NRC concludes that non-cooling system effects on terrestrial resources during the license
renewal term (initial LR or SLR) could be SMALL, MODERATE, or LARGE. This is a Category 2
issue.
4.6.1.1.2

Exposure of Terrestrial Organisms to Radionuclides

This issue concerns the potential impacts on terrestrial organisms from exposure to
radionuclides from routine radiological effluent releases during an initial LR or SLR term.
The 1996 LR GEIS did not address this issue. In 2007, the International Commission on
Radiation Protection (ICRP) issued revised recommendations for a system of protection to
control exposure from radiation sources (ICRP 2007). The recommendations included a section
about the protection of the environment in which the ICRP found that a clearer framework for
assessing nonhuman organisms was warranted. The ICRP indicated that it would develop a set
of reference animals and plants as the basis for relating exposure to dose, and dose to radiation
effects, for different types of organisms. This information would then provide a basis from which
agencies and responsible organizations could make policy and management decisions.
Subsequently, the ICRP developed and published a set of 12 reference animals and plants
(ICRP 2008a, ICRP 2009). They include a large and small terrestrial mammal, an aquatic bird,
and a large and small terrestrial plant, among others. The ICRP also issues publications and
information related to radiological effects and radiosensitivity in non-human biota
(Adam-Guillermin et al. 2018).
In 2009, following the NRC staff’s review of the ICRP’s 2007 recommendations, the
Commission found that there is no evidence that the NRC’s current set of radiation protection
controls is not protective of the environment (NRC 2009e). For this reason, the Commission
determined that the NRC staff should not develop separate radiation protection regulations for
plant and animal species (NRC 2009e).3 The Commission directed the NRC staff to continue
monitoring international developments on this issue and to keep the Commission informed.
3

See also SECY-04-0223 (NRC 2004f), SECY-06-0168 (NRC 2006g), SECY-08-0197 (NRC 2008c),
SECY-04-0055 (NRC 2004e), and related Staff Requirements Memorandums SRM-SECY-04-0223 (NRC
2005e), SRM-SECY-06-0168 (NRC 2005f), SRM-SECY-08-0197 (NRC 2009e), and SRM-SECY-04-0055
(NRC 2004d).

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Nonetheless, the NRC addressed radiological exposure of nonhuman organisms in the
2013 LR GEIS due to public concern about these impacts at some nuclear power plants.
In the 2013 LR GEIS, the NRC determined that the impacts of exposure of terrestrial organisms
to radionuclides would be SMALL at all nuclear power plants. Therefore, this was considered a
Category 1 issue for all nuclear power plants.
Radionuclides may be released from nuclear power plants into the environment through several
pathways. During normal operations and potentially during refurbishment, nuclear power plants
can release gaseous emissions that deposit small amounts of radioactive particulates in the
surrounding environment. Gaseous emissions typically include krypton, xenon, and argon
(which may or may not be radioactive), tritium, isotopes of iodine, and cesium. Emissions may
also include strontium, cobalt, and chromium. Radionuclides may also be released into water as
liquid effluent. Terrestrial plants can absorb radionuclides that enter shallow groundwater or
surface waters through their roots. Animals may experience exposure to ionizing radiation
through direct contact with air, water, or other media; inhalation; or ingestion of contaminated
food, water, or soil.
The U.S. Department of Energy (DOE) has produced a standard on a graded approach for
evaluating radiation doses to terrestrial and aquatic biota (DOE 2019). The DOE standard
provides methods, models, and guidance that can be used to characterize radiation doses to
terrestrial and aquatic biota exposed to radioactive material (DOE 2019). The following DOE
guidance dose rates are the levels below which no adverse effects to resident populations are
expected:
• riparian animal (0.1 radiation-absorbed dose per day [rad/d]; 0.001 gray per day [Gy/d])
• terrestrial animal (0.1 rad/d) (0.001 Gy/d)
• terrestrial plant (1 rad/d) (0.01 Gy/d)
• aquatic animal (1 rad/d) (0.01 Gy/d)
Previously, in 1992, the International Atomic Energy Agency (IAEA 1992) had also concluded
that chronic dose rates of 0.1 rad/d (0.001 Gy/d) or less do not appear to cause observable
changes in terrestrial animal populations. The United Nations Scientific Committee on the
Effects of Atomic Radiation concluded in 1996 and re-affirmed in 2008 that chronic dose rates of
less than 0.1 mGy/hr (0.24 rad/d or 0.0024 Gy/d) to the most highly exposed individuals would
be unlikely to have significant effects on most terrestrial communities (UNSCEAR 2010).
In the 2013 LR GEIS, the NRC estimated the total radiological dose that the four non-human
receptors listed above (i.e., riparian animal, terrestrial animal, terrestrial plant, and aquatic
animal) would be expected to receive during normal nuclear power plant operations based on
plant-specific radionuclide concentrations in water, sediment, and soils at 15 operating nuclear
power plants using Argonne National Laboratory’s RESRAD-BIOTA dose evaluation model.
The NRC found that total calculated dose rates for all terrestrial receptors at all 15 plants were
significantly less than the DOE guideline values. As a result, the NRC anticipated in the
2013 LR GEIS that normal operations of these facilities would not result in negative effects on
terrestrial biota. The 2013 LR GEIS concluded that the impact of radionuclides on terrestrial
biota from past operations would be SMALL for all nuclear plants and would not be expected to
change appreciably during the license renewal period.

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In this revision, the NRC staff conducted an updated and expanded analysis for this issue to
assess whether the 2013 LR GEIS conclusions are valid for initial LR and apply to the SLR
term. As part of this expanded analysis, the staff reviewed effluent release reports, performed
additional RESRAD-BIOTA dose calculations, and analyzed dose to biota using the ICRP biota
dose calculator. The staff reviewed a subset of operating pressurized water reactor (PWR) and
boiling water reactor (BWR) plants4 to evaluate the potential impacts of radionuclides on
terrestrial biota from continued operations. The staff reviewed effluent releases for this subset of
plants between 2013 and 2020 to evaluate releases since the 2013 LR GEIS was published.
The staff found that all data for this time period were below reportable thresholds.
The NRC staff evaluated Radiological Environmental Monitoring Program (REMP) reports for
the year 2020 for the subset of operating PWR and BWR plants. This review yielded expected
radionuclide concentrations in the environment that may be sourced from nuclear power plants.
In addition to regulated Lower Limits of Detection (LLD) stated in NUREG-1301 and
NUREG-1302 (NRC 1991b, NRC 1991a), the NRC staff obtained site-specific radionuclide
concentrations and LLDs in water, sediment, and soils when available from the REMP reports.
To estimate radioactive impacts to environmental receptors, the staff used the RESRAD-BIOTA
dose evaluation model (DOE 2004c) to calculate estimated dose rates for terrestrial biota (see
Section G.6.2 in Appendix G for further details on this approach). The values reported in the
reviewed REMP reports were frequently listed as being below the LLD. Measurements below
the LLD are too low to statistically confirm the presence of the radionuclide in the sample.
Accordingly, the staff conducted a RESRAD-BIOTA analysis using either the maximum values
from a measured media concentration or an LLD, when all measurements for that radionuclide
were below detection limits. The staff then aggregated these values to form a single
RESRAD-BIOTA analysis. This method is considered a bounding analysis because it assumes
that all radionuclides included in the RESRAD-BIOTA analysis are present in the environment,
even though some radionuclides are not confirmed to actually be present (i.e., those
radionuclides that are below the LLD). Table 4.6-1 presents the results of the NRC staff’s
RESRAD-BIOTA analysis. This table shows the total dose estimates to the four ecological
receptors: riparian animal,5 terrestrial animal, terrestrial plant, and aquatic animal.
Table 4.6-1

Estimated Radiation Dose Rates to Terrestrial Ecological Receptors from
Radionuclides in Water, Sediment, and Soils at U.S. Nuclear Power Plants

Receptor
Sum of Total Dose (rad/d)(a)(b)

Riparian
Animal
4.86 × 10-2

Terrestrial
Animal
1.25 × 10-2

Terrestrial
Plant
9.18 × 10-3

Aquatic
Animal
7.48 × 10-2

(a) Dose rates were estimated with RESRAD-BIOTA (DOE 2004c) by using site-specific radionuclide concentrations
and lower limits of detection in water, sediment, and soils obtained from the REMP reports.
(b) These values exclude potassium-40 because it is a naturally occurring radionuclide.

All dose estimates found using RESRAD-BIOTA and shown in Table 4.6-1 were below the DOE
guideline dose levels. Based on the staff’s analysis, it is unlikely that radionuclide releases
during normal operations of these nuclear power plants would have adverse effects on resident
populations of these biota because calculated doses are below protective guidelines.
4

The subset of plants included the following PWR plants: Comanche Peak, D.C. Cook, Palo Verde 1-3,
Robinson, Salem 1-2, Seabrook, and Surry; and the following BWR plants: Fermi 2, Hatch 1-2, Hope
Creek, Limerick, and Columbia.
5
Defined in RESRAD-BIOTA as an animal that was assumed to spend approximately 50 percent of its
time in aquatic environments and 50 percent of its time in terrestrial environments.

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In addition to the RESRAD-BIOTA analysis discussed above, the NRC staff estimated dose
rates to a riparian organism using the ICRP biota dose calculator (ICRP 2022) (see
Section G.6.2 in Appendix G for full description of ICRP BiotaDC methodology). A small subset
of nuclear power plant REMP reports6 were evaluated to determine available non-human biota
tissue concentrations for the ICRP biota dose calculator analysis. These tissue concentrations,
as well as site-specific LLDs and media measurements for surface water and soil when
available, were used to estimate a dose to a riparian organism. The staff used the ICRP
BiotaDC tool to develop dose coefficients (DCs, expressed in μGy h-1 per Bq kg-1) for water and
soil/sediment exposure of a generic organism. A hypothetical small burrowing mammal with
mass of 0.016 kg was chosen as a representative “riparian” organism. The mass and
dimensions of the animal are similar to that of the meadow jumping mouse (Zapus hudsonius),
a common North American rodent (Smith 1999). The staff developed DCs using the ICRP’s
BiotaDC v.1.5.2, which incorporates the radionuclide decay data of ICRP 107 (ICRP 2008b).
The staff established this methodology to obtain conservative dose estimates (see
Section G.6.2 in Appendix G for a further discussion of methodology). None of the radionuclides
evaluated singly, or in common, produced dose rates that approached the DOE’s guidance
dose rate of 0.1 rad/d for riparian animals using the ICRP BiotaDC tool (DOE 2019). The dose
rates calculated for the riparian organism ranged between 2 × 10-4 and 2 × 10-5 rad/d, which is
orders of magnitude lower than the DOE guideline dose rate. Additionally, the calculated dose
rates did not approach the level advocated by the National Council on Radiation Protection and
Measurements to initiate additional evaluation (Cool et al. 2019). In fact, the dose rates for the
riparian organism calculated using the ICRP’s calculator were lower than the RESRAD
conservative analysis, and both were well below the DOE guideline values.
Initial LR or SLR would continue current operating conditions and environmental stressors
rather than introduce wholly new impacts. Therefore, the impacts of current operations and
initial LR or SLR on terrestrial organisms would be similar. For these reasons, the effects of
exposure of terrestrial organisms to radionuclides would be minor and would neither destabilize
nor noticeably alter any important attribute of populations of exposed organisms during the
initial LR or SLR terms of any nuclear power plants. Continued adherence of nuclear power
plants to regulatory limits on radioactive effluent releases would minimize the potential impacts
on the terrestrial environment. Doses to terrestrial organisms would be expected to remain
within the DOE’s guidance dose levels and, therefore, impacts to terrestrial communities are not
expected. The staff reviewed information in scientific literature and from SEISs (for initial LRs or
SLRs) completed since development of the 2013 LR GEIS and identified no new information or
situations that would result in different impacts for this issue for either an initial LR or SLR term.
The NRC concludes that the impacts of exposure of terrestrial organisms to radionuclides
during the license renewal term (initial LR or SLR) would be SMALL for all nuclear power plants.
This is a Category 1 issue.
4.6.1.1.3

Cooling System Impacts on Terrestrial Resources (Plants with Once-Through
Cooling Systems or Cooling Ponds)

This issue concerns the potential impacts of once-through cooling systems and cooling ponds at
nuclear power plants on terrestrial resources during an initial LR or SLR term. The impacts of
plants with cooling towers on terrestrial resources are addressed in Sections 4.6.1.1.4
and 4.6.1.1.5.

6

The subset of plants included Comanche Peak, Columbia, and Callaway.

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In the 1996 and 2013 LR GEISs, the NRC determined that cooling system impacts on
terrestrial resources would be SMALL. Therefore, this was considered a Category 1 issue.
The 1996 LR GEIS considered this issue for nuclear power plants with cooling ponds; the
2013 LR GEIS expanded this issue to include plants with once-through cooling systems.
Cooling system operation can alter the ecological environment in a manner that affects
terrestrial resources. Such alterations may include thermal effluent additions to receiving
waterbodies; chemical effluent additions to surface water or groundwater; impingement of
waterfowl; disturbance of terrestrial plants and wetlands associated with maintenance dredging;
disposal of dredged material; and erosion of shoreline habitat.
Thermal effluents discharged from once-through cooling systems and cooling ponds can
contribute to localized elevated water temperatures in receiving waterbodies that may affect the
distributions of some terrestrial plants and animals in adjacent riparian or wetland habitats. For
example, at the Robinson plant in South Carolina, the growth of plants along the cooling pond
shoreline is restricted by the thermal effluent (NRC 2003a). In general, however, thermal
impacts on the terrestrial environment have not been identified at nuclear power plants. Thermal
effluents to waters of the United States are regulated through NPDES permits to limit the effects
of such discharges on the ecological environment. In addition, because wetland and riparian
plant communities present near nuclear power plants have been influenced by many years of
facility operation, elevated temperatures are unlikely to result in the mortality of any plants that
may be exposed to effluent discharges because vegetation present in these areas has likely
acclimated to local conditions. The available information indicates that the effects of thermal
effluents on the terrestrial environment is not of concern for license renewal.
Along with thermal effluents, nonradiological chemical contaminants may be present in cooling
system discharges. Terrestrial plants and animals may be exposed to these contaminants by
direct contact with effluent discharges or through uptake from contaminated food or water.
Plants and animals associated with wetland or riparian communities along the receiving
waterbody, along with waterfowl and other wildlife that forage in these waters, are the most
likely to be exposed to such chemicals, and exposure may have adverse impacts on these
organisms. Contaminants of potential concern include chlorine and other biocides, heavy
metals, VOCs, and oil products. NPDES permits typically limit the allowable concentrations of
these contaminants in liquid effluent to minimize impacts on the ecological environment.
Because of the low concentrations of nonradiological chemical contaminants within liquid
effluents, the uptake and accumulation of contaminants in the cells of exposed plants or animals
are not expected to be a significant issue for license renewal. Radionuclide contaminants, such
as tritium and strontium, are discussed in Section 4.6.1.1.2 as a separate license renewal issue.
In the past, heavy metals used in condenser tubing was found to be an issue at two plants.
Elevated concentrations of these contaminants are toxic to terrestrial organisms. Copper alloy
condenser tubes in the cooling systems at the Robinson plant and the Diablo Canyon plant in
California resulted in the discharge of copper in these plants’ liquid effluent. At Robinson, these
metals resulted in adverse effects on the morphology and reproduction of resident bluegill
(Lepomis macrochirus) populations (Harrison 1985). At Diablo Canyon, abalone
(Haliotis species) deaths were attributed to exposure to copper in plant effluents (NRC 1996).
Terrestrial wildlife that feed on these aquatic organisms could have also been exposed to
elevated copper levels and could have experienced adverse effects. However, these nuclear
power plants subsequently replaced the copper alloy condenser tubes with tubes made of
different materials (e.g., titanium), which has eliminated these impacts. This issue has not been

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reported at any other nuclear power plants. The available information indicates that the effects
of heavy metals on the terrestrial environment is not of concern for license renewal.
Groundwater quality can be degraded by nonradiological contaminants present in cooling ponds
and cooling canals. Deep-rooted terrestrial plants could be exposed to these contaminants.
However, as noted above, nonradiological contaminant concentrations are typically very low,
and any effects on terrestrial plants would be expected to be SMALL. Mitigation may also be
implemented where sensitive resources could be affected. At the Turkey Point plant in Florida,
for example, the flow of hypersaline groundwater from the cooling canals toward the Everglades
to the west is prevented by an interceptor ditch, located along the west side of the canal system,
from which groundwater inflow is extracted (NRC 2002a). However, since the publication of the
2013 LR GEIS, new information indicates that the interceptor ditch has not prevented movement
of hypersaline groundwater in the deeper Biscayne aquifer. Based on ecological monitoring
data, the NRC concluded that movement of the hypersaline water did not have discernable
ecological impacts. Data also suggest that the interceptor ditch did prevent westward movement
of near surface groundwater (NRC 2019c). This issue has not been identified at any other
operating nuclear power plant.
The impingement of waterfowl at cooling water intakes has been observed at some nuclear
power plants, such as the D.C. Cook plant in Michigan, Nine Mile Point plant in New York, and
Point Beach plant in Wisconsin. About 400 ducks, primarily lesser scaup (Aythya affinis), were
impinged at D.C. Cook in December 1991 (Mitchell and Carlson 1993); about 100 ducks, both
greater scaup (Aythya marila) and lesser scaup, were impinged in January 2000 at Nine Mile
Point (NRC 2006b). At the Point Beach plant, several double-crested cormorants
(Phalacrocorax auritus) were impinged in September 1990, and 33 birds (mostly gulls) were
impinged from June 2001 through December 2003 (NRC 2005a). These nuclear power plants
have changed operational procedures, such as periodically cleaning zebra mussels
(Dreissena polymorpha) off intake structures or have changed intake structure designs to
minimize impacts on waterfowl. This issue has not been found to be a problem at any other
nuclear power plants or in any of the initial LR or SLR reviews conducted since publication of
the 2013 LR GEIS. The available information indicates that bird impingement is not of concern
for license renewal.
Maintenance dredging near cooling system intakes or outfalls may physically disturb or alter
wetland or riparian habitats. Dredging may alter current patterns or increase local water
velocities and cause erosion of shoreline wetlands or riparian habitats. Dredging and disposal of
dredged material would likely require the nuclear power plant operator to obtain a CWA
Section 404 permit from the USACE. BMPs and conditions associated with these permits would
minimize impacts on the ecological environment. Granting of such permits would also require
the USACE to conduct its own environmental reviews prior to the undertaking of dredging.
License renewal would continue current operating conditions and environmental stressors rather
than introduce wholly new impacts. Therefore, the impacts of once-through cooling systems and
cooling ponds on terrestrial resources would be similar. For these reasons, the effects of these
systems on terrestrial resources would be minor and would neither destabilize nor noticeably
alter any important attribute of populations of plants or animals during the initial LR or
SLR terms of any nuclear power plants. The staff reviewed information in scientific literature and
from SEISs (for initial LRs and SLRs) completed since development of the 2013 LR GEIS and
identified no new information or situations that would result in different impacts for this issue for
either an initial LR or SLR term, as described above.

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The NRC concludes that cooling system impacts on terrestrial resources during the license
renewal term (initial LR or SLR) would be SMALL for nuclear power plants with once-through
cooling systems or cooling ponds. This is a Category 1 issue.
4.6.1.1.4

Cooling Tower Impacts on Terrestrial Plants

This issue concerns the potential impacts of cooling tower operation on terrestrial plant
communities during an initial LR or SLR term. This issue applies only to nuclear power plants
with cooling towers. Terrestrial habitats near cooling towers can be exposed to particulates,
such as salt, and can experience increased humidity, which can deposit water droplets or ice on
vegetation. These effects can lead to structural damage and changes in plant communities.
In the 1996 and 2013 LR GEISs, the NRC determined that cooling tower impacts on terrestrial
plants would be SMALL. Therefore, this was considered a Category 1 issue for all nuclear
power plants with cooling towers. The 1996 LR GEIS evaluated this issue as two separate
issues; the 2013 LR GEIS consolidated the two issues into one issue. This LR GEIS refines the
title of this issue from “Cooling tower impacts on vegetation (plants with cooling towers)” to
“Cooling tower impacts on terrestrial plants” for clarity and consistency with other ecological
resource GEIS issue titles.
Cooling tower drift contains small amounts of particulates that are dispersed over a wide area.
Most deposition from cooling towers, regardless of cooling tower type, occurs in close proximity
to the towers. Particulates from natural draft towers generally disperse over a larger area, while
particulates from mechanical draft towers tend to concentrate closer to the towers (Roffman and
Van Vleck 1974). Generally, particulate deposition from cooling towers has not resulted in
measurable adverse impacts on vegetation. At most nuclear power plants with cooling towers,
no effects on agricultural crops or natural plant communities have been observed (NRC 1996).
Where impacts have been observed, vegetation has typically adapted to cooling tower operation
following the period of initial operation. For instance, at Palisades Nuclear Plant (Palisades) (no
longer operating) on Lake Michigan, condensate plumes and drift associated with the site’s two
mechanical draft cooling towers caused the loss of about 5 ac (2 ha) of vegetation on dune
ridges adjacent to the cooling towers within the first several years of operation (NRC 1996).
Within 4 months of plant startup, white pines (Pinus strobus) near the cooling towers began to
show signs of chemically induced injury. During the second summer of operation, deciduous
trees began exhibiting observable effects. Researchers determined that sulfate deposition from
the cooling towers was responsible for the damage. Severe icing associated with the cooling
towers during the following winter further damaged these trees, and within the first several years
of operation, early successional scrub-shrub vegetation had replaced the mature forest stand.
Subsequently, Palisades stopped adding sulfuric acid to the cooling water, which eliminated
observable effects on vegetation. The NRC (NRC 2006d) anticipated no additional impacts
associated with cooling tower drift during the license renewal period.
Icing of vegetation and roads can occur near mechanical draft towers when fog is present and
temperatures are below freezing. Associated impacts have been rare, minor, and localized. The
1996 LR GEIS reports the results of vegetation monitoring at 10 plants with mechanical draft
cooling towers and 8 nuclear power plants with natural draft cooling towers. Vegetation at only
three sites exhibited ice-related damage: the Palisades plant (discussed above), Prairie Island
Nuclear Generating Plant (Prairie Island) in Minnesota, and Catawba Nuclear Station (Catawba)
in North Carolina. At Prairie Island, researchers observed frequent ice damage to red oaks
(Quercus rubra) adjacent to the site’s mechanical draft cooling towers and a subsequent change
in canopy structure (NRC 1996). Acorn viability was also found to be low, although acorn

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production appeared normal. In 1984, Prairie Island stopped operating the cooling towers during
the winter, which eliminated these impacts. At Catawba, researchers observed the browning of
the needles on several loblolly pines (Pinus taeda) within 200 ft (61 m) of the mechanical draft
cooling towers that was attributed to possible icing effects (NRC 1996). During license renewal,
the NRC anticipated no additional impacts associated with cooling tower drift at either of these
nuclear power plants (NRC 2011a, NRC 2002b).
The 1996 LR GEIS contemplated that salt deposition could be a concern at coastal nuclear
power plants that use estuarine or marine water for cooling. The only such plant is Hope Creek
in New Jersey, whose natural draft cooling towers withdraw cooling water from the Delaware
River estuary (see Section 3.3.2 for a discussion of Hope Creek cooling tower drift emissions).
However, no measurable effects on plant communities near Hope Creek’s cooling towers have
been observed (NRC 1996), and the NRC anticipated none during the license renewal period
(NRC 2011b). Soil salinization associated with cooling tower drift is also not expected to be an
issue because rainfall is sufficient to leach salts from the soil profile.
In summary, vegetation near nuclear power plant cooling towers has been exposed to many
years of cooling tower operation and has acclimated to any minor effects associated with
cooling tower drift. Icing effects would continue to be rare, minor, and localized. All nuclear
power plants at which effects of cooling tower drift were observed during the initial period of
operation have modified operations to mitigate these effects.
Initial LR or SLR would continue current operating conditions and environmental stressors
rather than introduce wholly new impacts. Therefore, the impacts of current operations and
license renewal on vegetation would be similar. For these reasons, the effects of cooling towers
on plants would be minor and would neither destabilize nor noticeably alter any important
attribute of plant populations during initial LR or SLR terms at nuclear power plants with cooling
towers. The staff reviewed information in scientific literature and from SEISs (for initial LRs and
SLRs) completed since development of the 2013 LR GEIS and identified no new information or
situations that would result in different impacts for this issue for either an initial LR or SLR term.
The NRC concludes that cooling tower impacts on terrestrial plants during the license renewal
term (initial LR or SLR) would be SMALL for all nuclear power plants with cooling towers. This is
a Category 1 issue.
4.6.1.1.5

Bird Collisions with Plant Structures and Transmission Lines

This issue concerns the risk of birds colliding with plant structures and transmission lines during
an initial LR or SLR term. Tall structures on nuclear power plant sites, such as cooling towers,
meteorological towers, and transmission lines, create collision hazards for birds that can result
in injury or death.
In the 1996 and 2013 LR GEISs, the NRC determined that the impacts of bird collisions with
plant structures and transmission lines would be SMALL. Therefore, this was considered a
Category 1 issue for all nuclear power plants. The 1996 LR GEIS evaluated this issue as two
separate issues; the 2013 LR GEIS consolidated them into one issue.
Throughout the United States, millions of birds are killed each year when they collide with
human-made objects, including buildings, windows, vehicles, transmission lines, communication
towers, wind turbines, cooling towers, and numerous other objects (Erickson et al. 2001).
Associated bird mortality is of concern if the stability of the population of a species is threatened

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or if the reduction in numbers within any bird population significantly impairs its function within
the ecosystem. Table 4.6-2 shows estimated annual bird collision mortality in the United States
from several categories of human-made objects. Collisions with buildings and windows account
for the greatest number of collision mortalities annually (365 to 988 million). Transmission lines
account for 12 to 64 million mortalities per year (Table 4.6-2).
As of April 2022, more than 133,000 standing communication towers (32 to 3,280 ft (10 to
1,000 m) in height) are registered with the Federal Communications Commission Antenna
Structure Registration database (FCC Undated), some of which have caused large numbers of
avian collision mortalities (Able 1973; Kemper 1996; Crawford and Engstrom 2001). Most large
mortality events occur at night during spring and fall migration periods and involve songbirds
that appear to become confused by tower lights (Taylor and Kershner 1986; Larkin and
Frase 1988; Manville 2005). For example, at a single television tower in northern Florida,
Crawford and Engstrom (2001) reported more than 44,000 bird collision mortalities over a
29-year period. Communication towers involved with the most bird collisions are tall (exceeding
1,000 ft [305 m]), illuminated at night with incandescent lights, guyed, and located near wetlands
and migration pathways (Manville 2005). During nights of heavy cloud cover or fog, the
incandescent lights illuminating the communication towers may attract migrating songbirds to
the towers, increasing the likelihood of collisions.
Table 4.6-2

Estimated Annual Bird Collision Mortality in the United States

Objects
Buildings and windows(b)
Vehicles(c)
Transmission lines(d)
Communication towers(e)
Wind generation facilities(f)
(a)
(b)
(c)
(d)
(e)
(f)
(g)

Estimated Annual Mortality (in millions)(a)
365 to 988
89 to 340
12 to 64
6.8
0.415 to 1.4(g)

Estimated annual mortality was extrapolated from literature reviews.
Includes residences, low-rises, and high-rises. Source: Loss et al. 2014.
Includes automobiles on roadways. Source: Loss et al. 2014.
Includes all electric communication lines and transmission lines. Source: Loss et al. 2014.
Includes mortality estimates from communication towers in Canada. Source: Longcore et al. 2012.
Includes wind turbines and supporting structures.
Based on projections from two studies (Smallwood et al. 2020 and Erickson et al. 2014).

Compared to communication towers, cooling towers at nuclear power plants are shorter
(generally less than 500 ft [152 m]), which may reduce the likelihood that migrating birds would
encounter cooling towers while in flight. Mechanical draft cooling towers, which are smaller
(usually shorter than 100 ft [30 m]), are thought to cause negligible mortality (NRC 1996).
Cooling towers are usually illuminated with low-intensity light sources (1.0 ft-candle or less) at
night, although it is unknown whether this attracts or detracts birds. Several nuclear power
plants with natural draft cooling towers have studied bird mortality, including plants within three
of the four major United States flyways. These include plants in the Atlantic Flyway
(Susquehanna, Beaver Valley, and Three Mile Island [no longer operating] in Pennsylvania),
Mississippi Flyway (Davis-Besse in Ohio and Arkansas Nuclear One [Arkansas] in Arkansas),
and Pacific Flyway (Trojan [no longer operating] in Oregon).
At the Susquehanna plant, researchers conducted bird mortality surveys during spring and fall
migration from 1978 through 1986. The plant’s natural draft towers are 165 m (540 ft) tall and
illuminated with 480V aircraft warning strobe lights. Researchers collected about 1,500 dead
birds representing 63 species during monitoring whose deaths were likely attributable to

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collisions with the cooling towers. Most were songbirds. Fewer collisions occurred after
Susquehanna began commercial operations; researchers considered that cooling tower vapor
plumes and noise may have discouraged birds from entering the area (NRC 1996).
At the Davis-Besse plant, researchers conducted bird mortality surveys during spring and fall
migration from 1972 to 1979. During this period, early morning surveys were conducted almost
daily at the 152 m tall (499 ft tall) cooling tower. Researchers collected 1,561 dead birds,
including 1,229 at the cooling tower, 224 around Unit 1 structures, and 108 at the
meteorological tower. Notably, after the cooling tower began operating in the fall of 1976, some
dead birds were discovered in the water outlets of the tower basin. Most mortalities were of
night-migrating songbirds, particularly wood-warblers (family Parulidae), vireos (Vireo species),
and kinglets (Regulus species). Waterfowl, which were abundant in nearby marshes and ponds,
suffered little collision mortality. Most collision mortalities at the cooling tower occurred during
years when the tower was not well illuminated. After the completion of Unit 1 structures and
installation of many safety lights around the buildings in the fall of 1978, collision mortality
significantly decreased. Observed mortalities averaged 236 per year from 1974 through 1977,
135 in 1978, and 51 in 1979. This reduction was attributed to low-intensity light sources
(1.0 ft-candle or less) that illuminated the cooling tower at night. Researchers concluded that
lights at nuclear power plants more successfully detract birds than do lights on communication
towers (NRC 2015e).
At the Fermi plant, researchers studied bird strikes from 2005 to 2014. The highest number of
bird strikes occurred in October 2007 when researchers found a total of 45 dead birds near the
south cooling tower (approximately 400 ft (122 m) tall) in a 1-week period. The licensee
conducted 2 years of follow-up monitoring in 2008 and 2009 to further investigate the numbers
and species of birds colliding with nuclear power plant structures. During this period,
researchers collected 31 dead birds and no more than 4 in any given week (NRC 2016c).
At the Beaver Valley plant, researchers conducted surveys at the cooling tower during spring
and fall migration from 1974 to 1978. Researchers collected 27 dead birds over the five-year
period. At the Trojan plant (no longer operating) researchers conducted weekly surveys in 1984
and 1988 at the cooling tower, meteorological tower, switchyard, and generation building. No
dead birds were found. At the Three Mile Island plant, researchers collected 66 dead birds near
the cooling towers from 1973 to 1975. No dead birds were found at the Arkansas plant, where
cooling tower monitoring was conducted twice weekly from October through April from 1978 to
1980 (NRC 2013a).
The available data on bird collision mortality associated with nuclear power plant cooling towers
and other structures suggest that nuclear power plants cause a small number of bird mortalities
annually. A large percentage of these mortalities occur during the spring and fall migratory
periods and primarily involve songbirds migrating at night. Natural draft cooling towers appear to
be the structures that pose the largest collision risk at nuclear power plant sites. Operating
cooling towers appear to detract birds; the vapor plume, noise, or lighting may mitigate the risk
of bird collision. Data are not available on bird injuries, but the NRC staff assumes that some
birds that collide with nuclear power plant structures are injured and either die later or suffer
reduced fitness until they recover. The relatively few nuclear power plants in the United States
that have natural draft towers, combined with the relatively low bird mortality at studied sites,
indicate that bird populations are unlikely to be measurably affected by collisions with nuclear
power plant structures and that the contribution of nuclear power plant sites to the cumulative
effects of bird collision mortalities in the United States is very small.

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The risk of bird collisions with site structures would remain the same for a given nuclear power
plant during an initial LR or SLR period. Because the number of associated bird mortalities is
small for any species, it is unlikely that losses would threaten the stability of local or migratory
bird populations or result in a noticeable impairment of the function of a species within the
ecosystem. Mitigation measures to reduce bird collisions may include illuminating natural draft
cooling towers and other tall structures at night with low-intensity lights so that birds can see the
structures and avoid colliding with them.
The potential for birds to collide with transmission lines depends on a number of factors, such
as species, migration behavior, and the location and physical characteristics of the transmission
line (Bevanger 1988; Janss 2000; Manville 2005). Larger-bodied bird species such as raptors
are more likely to collide with transmission lines (Harness and Wilson 2001; Manville 2005),
whereas smaller-bodied birds such as migrating songbirds are more likely to collide with towers
(Temme and Jackson 1979). This difference is most likely the result of differences in the
behaviors of raptors and songbirds. Raptors are known to use utility structures as perch
locations and nest sites more often than do songbirds (Manville 2005), whereas nocturnal
migrating songbirds may become confused by the lights on communication towers (Crawford
and Engstrom 2001). Lights are not a contributing factor in bird collisions at transmission lines
because lights are not generally used to mark transmission lines.
Transmission lines cause 12 million to 64 million bird mortalities per year (see Table 4.6-2).
However, no nuclear power plants have reported high bird collision mortality associated with
in-scope transmission lines. In a 1974 through 1978 study conducted at the Prairie Island plant,
a total of 453 bird deaths were attributed to collisions with transmission lines; most collisions
occurred during inclement weather (NRC 1996). Researchers collected dead mourning doves
(Zenaida macroura), starlings (family Sturnidae), red-winged blackbirds (Agelaius phoeniceus),
common grackles (Quiscalus quiscula), brown-headed cowbirds (Molothrus ater), ring-necked
pheasants (Phasianus colchicus), American coots (Fulica americana), and sora rails
(Porzana carolina) (NSP 1978). This study was conducted along large tracts of transmission
lines constructed to connect the Davis-Besse plant to the regional electric grid upon initial
operation. As described in Section 3.1.7, transmission lines relevant to initial LR or SLR include
only those lines that connect the nuclear power plant to the first substation that feeds into the
regional power distribution system. This substation is frequently, but not always, located on the
plant property. Many of the transmission lines that were constructed with nuclear power plants
are now interconnected with the regional electric grid and would remain energized regardless of
license renewal. Thus, the length of transmission lines directly associated with nuclear power
plants is a small fraction of the total length of transmission lines in the United States
(Manville 2005). Therefore, transmission lines associated with nuclear power plants are likely
responsible for a negligible number of bird collision mortalities per year.
The risk of bird collisions with transmission lines associated with nuclear power plants would
remain the same for a given nuclear power plant during an initial LR or SLR period. Because the
number of associated bird mortalities is negligible for any species, it is unlikely that losses would
threaten the stability of resident or migratory bird populations or result in a noticeable
impairment of the function of a species within the ecosystem.
Initial LR or SLR would continue current operating conditions and environmental stressors
rather than introduce wholly new impacts. Therefore, the impacts of current operations and
license renewal on birds would be similar. For these reasons, the effects of bird collisions with
plant structures and transmission lines would be minor and would neither destabilize nor
noticeably alter any important attribute of bird populations during initial LR or SLR terms at

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nuclear power plants. The staff reviewed information in scientific literature and from SEISs (for
initial LRs and SLRs) completed since development of the 2013 LR GEIS and identified no new
information or situations that would result in different impacts for this issue for either an initial LR
or SLR term. The NRC concludes that the impacts of bird collisions with plant structures or
transmission lines during the license renewal term (initial LR or SLR) would be SMALL for all
nuclear power plants. This is a Category 1 issue.
4.6.1.1.6

Water Use Conflicts with Terrestrial Resources (Plants with Cooling Ponds or
Cooling Towers Using Makeup Water from a River)

This issue concerns water use conflicts that may arise at nuclear power plants with cooling
ponds or cooling towers that use makeup water from a river and how those conflicts could affect
terrestrial resources during an initial LR or SLR term.
In the 1996 and 2013 LR GEISs, the NRC determined that the impacts of water use conflicts on
terrestrial resources would be SMALL at many nuclear power plants but that these impacts
could be MODERATE at some plants. Therefore, this was considered a Category 2 issue for
nuclear power plants with cooling ponds or cooling towers using makeup water from a river. The
1996 LR GEIS addressed cooling towers that withdraw water from small rivers with low flow; the
2013 LR GEIS expanded this issue to include all cooling towers that withdraw water from rivers.
Notably, this issue also applies to nuclear power plants with hybrid cooling systems that
withdraw makeup water from a river (i.e., once-through cooling systems with helper cooling
towers) (e.g., NRC 2020g).
Nuclear power plant cooling systems may compete with other users relying on surface water
resources, including downstream municipal, agricultural, or industrial users. Closed-cycle
cooling is not completely closed because the system discharges blowdown water to a surface
waterbody and withdraws water for makeup of both the consumptive water loss due to
evaporation and drift (for cooling towers) and blowdown discharge. For plants using cooling
towers, while the volume of surface water withdrawn is substantially less than once-through
systems for a similarly sized nuclear power plant, the makeup water needed to replenish the
consumptive loss of water to evaporation can be significant. Cooling ponds also require makeup
water. Section 4.5.1 addresses factors relevant to water use conflicts at nuclear power plants in
detail. Water use conflicts with terrestrial resources, especially riparian communities, could
occur when water that supports these resources is diminished by a combination of
anthropogenic uses.
Consumptive use by nuclear power plants with cooling ponds or cooling towers using makeup
water from a river during the license renewal term is not expected to change unless power
uprates, with associated increases in water use, occur. Such uprates would require separate
NRC review and approval. Any river, regardless of size, can experience low-flow conditions of
varying severity during periods of drought and changing conditions in the affected watershed,
such as upstream diversions and use of river water. However, the direct impacts on instream
flow and potential water availability for other users from nuclear power plant surface water
withdrawals are greater for small (i.e., low-flow) rivers.
To date, the NRC has identified water use conflicts with terrestrial resources at only one nuclear
power plant: Wolf Creek plant in Kansas. This plant uses Coffey County Lake for cooling, and
makeup water for the lake is drawn from the Neosho River downstream of John Redmond
Reservoir (NRC 2008a). The Neosho River is a small river with especially low water flow during
drought conditions. Riparian communities downstream of this reservoir may be affected by

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Wolf Creek makeup water withdrawals from the Neosho River during periods when the lake
level is low. During the license renewal review, the NRC found that water use conflicts would be
SMALL to MODERATE for this nuclear power plant. As part of the NRC’s ESA consultation
with the FWS, Wolf Creek developed and implemented a water level management plan for
Coffey County Lake, which includes withdrawing makeup water proactively during high river
flows to support downstream populations of the federally endangered Neosho madtom
(Noturus placidus), a small species of catfish (FWS 2012). This plan effectively mitigated not
only water use conflicts that the Neosho madtom might experience, but also the effects that
downstream riparian communities might experience from the plant’s cooling water withdrawals.
The NRC has identified no concerns about water use conflicts with terrestrial resources at any
other nuclear power plant with cooling ponds or cooling towers.
The staff reviewed information from SEISs (for initial LRs and SLRs) completed since
development of the 2013 LR GEIS. In summary, water use conflicts during an initial LR or
SLR term depend on numerous site-specific factors, including the ecological setting of the
nuclear power plant; the consumptive use of other municipal, agricultural, or industrial water
users; and the plants and animals present in the area. Water use conflicts with terrestrial
resources would be SMALL at most nuclear power plants with cooling ponds or cooling towers
that withdraw makeup from a river, but may be MODERATE at some plants. Therefore, a
generic determination of potential impacts on terrestrial resources from continued operations
during a license renewal term is not possible.
The NRC concludes that water use conflicts on terrestrial resources during the license renewal
term (initial LR or SLR) could be SMALL or MODERATE at nuclear power plants with cooling
ponds or cooling towers using makeup water from a river. This is a Category 2 issue.
4.6.1.1.7

Transmission Line Right-of-Way (ROW) Management Impacts on Terrestrial
Resources

This issue concerns the effects of transmission line ROW management on terrestrial plants and
animals during an initial LR or SLR term.
In the 1996 and 2013 LR GEISs, the NRC determined that transmission line ROW maintenance
impacts would be SMALL at all nuclear power plants. Therefore, this was considered a
Category 1 issue for all nuclear power plants. The 1996 LR GEIS evaluated this issue as two
separate issues; the 2013 LR GEIS consolidated them into one issue.
When this issue was originally contemplated in the 1996 LR GEIS, the NRC considered as part
of its plant-specific license renewal reviews all transmission lines that were constructed to
connect a nuclear power plant to the regional electric grid. However, in the 2013 GEIS, the NRC
clarified that the transmission lines relevant to license renewal include only the lines that
connect the nuclear power plant to the first substation that feeds into the regional power
distribution system (see Section 3.1.7). Typically, the first substation is located on the nuclear
power plant property within the primary industrial-use area. This decision was informed by the
fact that many of the transmission lines that were constructed with nuclear power plants are now
interconnected with the regional electric grid and would remain energized regardless of initial LR
or SLR. Accordingly, the discussion of this issue in this LR GEIS is brief because in-scope
transmission lines for license renewal tend to occupy only industrial-use or other developed
portions of nuclear power plant sites. Therefore, effects on terrestrial plants and animals are
generally negligible. The 1996 and 2013 LR GEISs provide further background about this issue
and discuss it in more detail.

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Utilities maintain transmission line ROWs so that the ground cover is composed of low-growing
herbaceous or shrubby vegetation and grasses. Generally, ROWs are initially established by
clear-cutting during transmission line construction and are subsequently maintained by physical
(e.g., mowing and cutting) and chemical (e.g., herbicides or pesticides) means. These activities
alter the composition and diversity of plant communities and generally result in lower-quality
habitat for wildlife. Heavy equipment used for ROW maintenance can crush vegetation and
compact soils, which can affect soil quality and reduce infiltration to shallow groundwater. This
is especially of concern in sensitive habitats, such as wetlands. Chemical herbicides can be
transported to neighboring undisturbed habitats through precipitation and runoff. Disturbed
habitats often favor non-native or nuisance species and can lead to their proliferation.
Noise and general human disturbance during ROW management can temporarily disturb wildlife
and affect their behaviors. The presence of ROWs can favor wildlife species that prefer edge or
early successional habitats. Some species, such as neotropical migrating songbirds that prefer
interior forest habitat may be adversely affected by the increase in edge habitat. These species
require large blocks of forest for successful reproduction and survival (Wilcove 1988). Studies
have found that nests of these bird species placed near edges are more likely to fail as a result
of predation or nest parasitism than nests located near the forest interior (Paton 1994; Robinson
et al. 1995). Transmission line ROWs may represent a barrier for species, such as large
mammalian carnivores, that require large tracts of contiguous forested habitat (Crooks 2002).
Maintenance of ROWs may also have negative effects on smaller, less mobile wildlife species.
For example, studies have shown that some amphibian species have difficulty crossing
disturbed habitat and may experience increased rates of mortality as a result of physiological
stress (Gibbs 1998; Rothermel 2004). Other wildlife may benefit from ROW habitat. For
instance, in a study of rodent populations in Oregon, Wolff et al. (1997) found higher densities of
gray-tailed voles (Microtus canicaudus) in disturbed open habitats than in other habitats.
Most nuclear power plants maintain procedures to minimize or mitigate the potential impacts
of ROW management. For instance, heavy machinery and herbicide use is often prohibited in
or near wetlands or surface waters. Procedures often include checklists to ensure that workers
obtain the necessary local, State, or Federal permits if work could affect protected resources.
At the Millstone Power Station (Millstone) in Connecticut, mowing is conducted only from
November through April to protect saturated soils and minimize loss of fruit and seeds
(NRC 2005d). At the Seabrook plant in New Hampshire, workers are trained to recognize
Federally or State-protected species to avoid impacts on them (NRC 2015b). At Browns Ferry
Nuclear Plant (Browns Ferry) in Alabama, all vegetation clearing in sensitive habitats is done by
hand, and vehicle and machinery use is prohibited (NRC 2005b).
Terrestrial communities in transmission line ROWs have been exposed to many years of
transmission line operation and have acclimated to regular ROW maintenance. License renewal
would continue current operating conditions and environmental stressors rather than introduce
wholly new impacts. Therefore, the impacts of current operations and license renewal on
terrestrial resources would be similar. Further, and as stated above, in-scope transmission lines
for license renewal tend to occupy only industrial-use or other developed portions of nuclear
power plant sites and, therefore, the effects of ROW maintenance on terrestrial plants and
animals during an initial LR or SLR term would be negligible. The staff reviewed information in
scientific literature and from SEISs (for initial LRs and SLRs) completed since development of
the 2013 LR GEIS and identified no new information or situations that would result in different
impacts for this issue for either an initial LR or SLR term.

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The NRC concludes that the transmission line ROW maintenance impacts on terrestrial
resources during the license renewal term (initial LR or SLR) would be SMALL for all nuclear
power plants. This is a Category 1 issue.
4.6.1.1.8

Electromagnetic Field Effects on Terrestrial Plants and Animals

This issue concerns the effects of EMFs on terrestrial plants and animals, including agricultural
crops, honeybees, wildlife, and livestock, during an initial LR or SLR term.
In the 1996 and 2013 LR GEISs, the NRC determined that the impacts of EMFs on terrestrial
plants and animals would be SMALL at all nuclear power plants. Therefore, this was considered
a Category 1 issue for all nuclear power plants. This LR GEIS refines the title of this issue from
“Electromagnetic fields on flora and fauna (plants, agricultural crops, honeybees, wildlife,
livestock)” to “Electromagnetic field effects on terrestrial plants and animals” for clarity and
consistency with other ecological resource LR GEIS issue titles.
When this issue was originally contemplated in the 1996 LR GEIS, the NRC considered as part
of its plant-specific license renewal reviews all transmission lines that were constructed to
connect a nuclear power plant to the regional electric grid. However, in the 2013 LR GEIS, the
NRC clarified that the transmission lines relevant to license renewal include only the lines that
connect the nuclear power plant to the first substation that feeds into the regional power
distribution system (see Section 3.1.7). Typically, the first substation is located on the nuclear
power plant property within the primary industrial-use area. This decision was informed by the
fact that many of the transmission lines that were constructed with nuclear power plants are now
interconnected with the regional electric grid and would remain energized regardless of initial LR
or SLR. Accordingly, the discussion of this issue in this LR GEIS is brief because in-scope
transmission lines for license renewal tend to occupy only industrial-use or other developed
portions of nuclear power plant sites. Therefore, the effects of EMFs on terrestrial plants and
animals are generally negligible. The 1996 and 2013 LR GEISs provide further background
about this issue and discuss it in more detail.
Operating transmission lines produce electric and magnetic fields, collectively referred to as
EMFs. EMF strength at the ground level varies greatly but is generally stronger for highervoltage lines. Corona is the electrical discharge occurring in air from EMFs; it can be detected
adjacent to phase conductors. Corona is generally not an issue for transmission lines of 345 kV
or less. Corona results in audible noise, radio and television interference, energy losses, and
ozone and nitrogen oxide production. Studies investigating the effects of EMFs produced by
operating transmission lines up to 1,100 kV have generally not detected any ecologically
significant impact on terrestrial plants and animals.
Miller (1983) determined that minor damage to plant foliage and buds can occur from coronarelated heat. Exhibited damage is like what plants might exhibit in response to drought. In one
experiment under an 1,100 kV prototype line, alder (Alnus species) and Douglas fir
(Pseudotsuga menziesii) trees exhibited reduced upward growth (Rogers et al. 1984). The
crowns of the trees became somewhat flattened on top and the overall crown developed a
broader appearance than usual. Growth of the lower parts of the trees and of lower-growing
plants, such as pasture grass, barley, and peas, were unaffected (Rogers and Hinds 1983).
Studies of agricultural crops, including corn, bluegrass, alfalfa, and sunflower, have detected no
effects or minor effects that did not ultimately affect germination or crop yield (Bankoske et al.
1976; Lee et al. 1989; Poznaniak and Reed 1978).

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The literature on the effect of EMF on wildlife is somewhat mixed, although most studies have
detected virtually no concern about the impacts of EMFs on animals. For instance, Kroodsma
(1984, 1987) found that the density of breeding birds under 500 kV lines in eastern Tennessee
is greater than that in adjacent forests and in most grassland habitats or agricultural fields.
A Minnesota study of a 500 kV line found little evidence of either a positive or negative effect of
the power line on bird populations (Niemi and Hanowski 1984). Schreiber et al. (1976) as cited
in the 2013 LR GEIS found that the density of small mammal populations near transmission
lines appears to depend on habitat type rather than on the presence of the lines. Bird and small
mammal populations under an 1,100 kV line in Oregon were also apparently unaffected by line
operation (Rogers and Hinds 1983). In a review of numerous studies on livestock, Lee et al.
(1989) found no evidence that the growth, production, or behavior of beef and dairy cattle,
sheep, hogs, or horses are affected by EMFs.
Other studies have observed the impacts of EMFs on animals. They showed that EMFs
influence the development, reproduction, and physiology of insects (Greenberg et al. 1981) and
mammals (Burchard et al. 1996). Fernie and Reynolds (2005) determined that EMF exposure
can alter the behavior, physiology, endocrine system, and the immune function of birds,
including passerines, birds of prey, and chickens studied in laboratory and field situations.
Nonetheless, birds often nest on transmission line structures. However, on high-voltage lines
supported by metal lattice towers, birds usually nest on the top bridge of the tower where EMF
strength is minimal (e.g., 5 kV/m or less) (Lee, Jr. 1980). The success of nests on transmission
line structures appears to be no different from nests in areas not exposed to EMFs (e.g., Gilmer
and Stewart 1983; Lee, Jr. 1980; Steenhof et al. 1993).
Honeybees in hives under transmission lines can suffer increased propolis (a resin-like material
produced to build hives) production, reduced growth, greater irritability, and increased mortality
(Greenberg and Bindokas 1985; Rogers and Hinds 1983). Bindokas et al. (1988) determined
that these impacts were the result of voltage buildup and electric currents within the hives. Bees
kept in moisture-free nonconductive conditions were not adversely affected, even in electric
fields as strong as 100 kV/m. These effects can also be mitigated by shielding hives with a
grounded metal screen or by moving them away from transmission lines (Rogers and Hinds
1983; Lee, Jr. 1980).
Plants and animals near transmission lines have been exposed to many years of transmission
line operation and associated EMFs. Initial LR or SLR would continue current operating
conditions and environmental stressors rather than introduce wholly new impacts. Therefore,
the impacts of current operations and initial LR or SLR on terrestrial resources would be similar.
Further, and as stated above, in-scope transmission lines for license renewal tend to occupy
only industrial-use or other developed portions of nuclear power plant sites and, therefore, the
effects of EMF on plants and animals during an initial LR or SLR term would be negligible. The
staff reviewed information in scientific literature and from SEISs (for initial LRs and SLRs)
completed since development of the 2013 LR GEIS and identified no new information or
situations that would result in different impacts for this issue for either an initial LR or SLR term.
The NRC concludes that the effects of EMFs on plants and animals during the license renewal
term (initial LR or SLR) would be SMALL for all nuclear power plants. This is a Category 1
issue.
4.6.1.2

Aquatic Resources

Continued operation of a nuclear power plant during a license renewal term involves continued
cooling water intake system operation, including source water withdrawals and effluent

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discharges; gaseous and liquid effluent releases; facility upkeep, including transmission line
maintenance; and construction or ground-disturbing activities, in cases where license renewal
necessitates refurbishment. Aquatic organisms would continue to be subject to the effects of
impingement, entrainment, thermal discharges, chemical and radiological contaminants, and
erosion and sedimentation.
This section considers the effects that aquatic resources may experience as a result of initial LR
or SLR. These issues are as follows:
• impingement mortality and entrainment of aquatic organisms (plants with once-through
cooling systems or cooling ponds)7,8
• impingement mortality and entrainment of aquatic organisms (plants with cooling towers)7,8
• entrainment of phytoplankton and zooplankton9
• effects of thermal effluents on aquatic organisms (plants with once-through cooling systems
or cooling ponds)9
• effects of thermal effluents on aquatic organisms (plants with cooling towers)9
• infrequently reported effects of thermal effluents10
• effects of nonradiological contaminants on aquatic organisms
• exposure of aquatic organisms to radionuclides
• effects of dredging on aquatic resources9
• water use conflicts with aquatic resources (plants with cooling ponds or cooling towers using
makeup water from a river)
• non-cooling system impacts on aquatic resources9
• impacts of transmission line right-of-way (ROW) management on aquatic resources
Impingement and Entrainment
Impingement occurs when organisms are trapped against the outer part of an intake structure’s
screening device (79 FR 48300). The force of the intake water traps the organisms against the
screen, and individuals are unable to escape. Impingement can kill organisms immediately or
cause exhaustion, suffocation, injury, and other physical stresses that contribute to later
mortality. The potential for injury or death is generally related to the amount of time an organism
is impinged, its fragility (susceptibility to injury), and the physical characteristics of the screen
wash and fish return systems of the intake structure. Because some individuals may survive
impingement, this effect is often assessed in terms of impingement mortality. The EPA has
7

This issue was modified from the 2013 LR GEIS to address updated regulatory criteria under CWA
Section 316(b).
8 This issue was consolidated to include the impingement component of the 2013 LR GEIS issue, “Losses
from predation, parasitism, and disease among organisms exposed to sublethal stresses.”
9 Issue retitled from the 2013 LR GEIS for clarity and consistency with other ecological resource issues.
No substantive changes to this issue have been made.
10 Issue consolidated to include the 2013 LR GEIS issue, “Effects of cooling water discharge on dissolved
oxygen, gas supersaturation, and eutrophication,” and the thermal effluent component of the
2013 LR GEIS issue, “Losses from predation, parasitism, and disease among organisms exposed to
sublethal stresses.”

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found that impingement mortality is typically less than 100 percent if the cooling water intake
system includes fish return or backwash systems. Because impingeable organisms are typically
fish with fully formed scales and skeletal structures and well-developed survival traits, such as
behavioral responses to avoid danger, many impinged organisms can survive under proper
conditions.
Depending on the configuration of the cooling water intake system, impinged organisms may
also become entrapped. Entrapment occurs when impingeable fish and shellfish lack the means
to escape the cooling water intake. Entrapment includes but is not limited to organisms caught
in the bucket of a traveling screen and unable to reach a fish return; organisms caught in the
forebay of a cooling water intake system without any means of being returned to the source
waterbody without experiencing mortality; or cooling water intake systems where the velocities
in the intake pipes or in any channels leading to the forebay prevent organisms from being able
to return to the source waterbody through the intake pipe or channel (40 CFR 125.92(j)).
Entrainment occurs when organisms pass through the screening device and travel through the
entire cooling system, including the pumps, condenser or heat exchanger tubes, and discharge
pipes (79 FR 48300). Organisms susceptible to entrainment are of smaller size, such as
ichthyoplankton, meriplankton, zooplankton, and phytoplankton. During travel through the
cooling system, entrained organisms experience physical trauma and stress, pressure changes,
excess heat, and exposure to chemicals (Mayhew et al. 2000). Because entrainable organisms
generally consist of fragile life stages (e.g., eggs, which exhibit poor survival after interacting
with a cooling water intake structure, and early larvae, which lack a skeletal structure and
swimming ability), the EPA has concluded that, for purposes of assessing the impacts of a
cooling water intake system on the aquatic environment, all entrained organisms die
(79 FR 48300).
Entrainment susceptibility is highly dependent upon life history characteristics. For example,
broadcast spawners with nonadhesive, free-floating eggs that drift with water current may become
entrained in a cooling water intake system. Nest-building species or species with adhesive,
demersal eggs are less likely to become entrained during their early life stages. The susceptibility
of larval life stages to entrainment depends on body morphometrics and swimming ability.
If several life stages of a species occupy the source water, that species can be susceptible to
both impingement and entrainment. For instance, adults and juveniles of a given species of fish
may be impinged against the intake screens, while larvae and eggs may pass through the
screening device and be entrained through the cooling system. The susceptibility to either
impingement or entrainment is related to the size of the individual relative to the size of the
mesh on the screening device. By definition, the EPA considers aquatic organisms that can be
collected or retained on a sieve that has 0.56 in. (1.4 centimeters [cm]) diagonal openings to be
susceptible to impingement (79 FR 48300). This equates to screen device mesh openings of
1/2 in. by 1/4 in. (1.3 cm by 0.635 cm), which is slightly larger than the openings on the typical
3/8-in. (0.95-cm) square mesh found at many nuclear power plants. Organisms smaller than the
0.56 in. (1.4 cm) mesh are considered susceptible to entrainment.
The magnitude of impacts that impingement mortality and entrainment (IM&E) create on the
aquatic environment depends on the nuclear power plant-specific characteristics of the cooling
system as well as characteristics of the local aquatic community. Relevant nuclear power plant
characteristics include the location of the cooling water intake structure, intake velocities,
withdrawal volumes, screening device technologies, and the presence or absence of a fish
return system. Impingement and impingement mortality reduction technologies can greatly

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reduce the likelihood of impingement mortality of susceptible organisms. Relevant
characteristics of the aquatic community include species present in the environment, life history
characteristics, population abundances and distributions, special species statuses and
designations, and regional management objectives.
The most visible direct impacts of IM&E are the losses of large numbers of aquatic organisms,
distributed nonuniformly among fish, benthic invertebrates, phytoplankton, zooplankton, and
other susceptible aquatic taxa (e.g., sea turtles). These losses have immediate and direct
effects on the population size and age distribution of affected species and may cascade through
food webs (79 FR 48300).
Ichthyoplankton are early life stages of finfish, including eggs, yolk-sac larvae, and post
yolk-sac larvae.
Meriplankton are larval stages of shellfish and other macroinvertebrates.
Zooplankton are animals that either spend their entire lives as plankton (holoplankton) or
exist as plankton for a short time during development (meroplankton).
Phytoplankton are single-celled plant plankton and include diatoms (single-celled yellow
algae) and dinoflagellates (a single-celled organism with two flagella).
In some cases, IM&E have been shown to be a significant source of anthropogenic mortality of
depleted stocks of commercially targeted species. For example, approximately 5.4 percent of
the estimated A1E population of the Southern New England/Massachusetts stock of winter
flounder (Pseudopleuronectes americanus) is lost to IM&E (NEFSC 2011). IM&E also increase
the pressure on native freshwater species, such as lake whitefish (Coregonus clupeaformi) and
yellow perch (Perca flavescens), whose populations have seen dramatic declines in recent
years (79 FR 48300).
IM&E are also likely to contribute to reduced population sizes of species targeted by commercial
and recreational fishers, particularly for stocks that are being harvested at unsustainable levels
or that are undergoing rebuilding. Thus, reducing IM&E may lead to more rapid stock recovery,
a long-term increase in commercial fish catches, increased population stability following periods
of poor recruitment and, as a consequence of increased resource utilization, an increased ability
to minimize the invasion of exotic species (Stachowicz and Byrnes 2006).
Table 4.6-3 lists taxa commonly impinged or entrained at nuclear power plants by ecosystem
type. Specific species vary by region. For instance, in northeastern estuaries, common herrings
(family Clupidae) include alewife (Alosa pseudoharengus), blueback herring (A. aestivalis), and
American shad (A. sapidissima). In southeastern estuaries, skipjack herring (A. chrysochloris)
and threadfin shad (D. petenense) are prevalent. Gizzard shad (D. cepedianum) are found in
estuarine waters all along the eastern coast and the Gulf of Mexico.

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Table 4.6-3

Commonly Impinged and Entrained Taxa at Nuclear Power Plants by
Ecosystem Type

Family
Carangidae

Common Name
jacks and pompanos

Ocean
x

Estuaries
-

Rivers
-

Great Lakes
-

Centrarchidae

sunfishes and crappies

-

-

x

-

Clupeidae

herrings

-

x

x

x

Cottoidei

sculpins

-

-

-

x

Cyprinidae

carps and minnows

-

-

x

-

Engraulidae

anchovies

x

x

-

-

Ephippidae

x

-

-

-

Gobiidae

spadefishes, batfishes,
and scats
gobies

x

-

-

-

Ictaluridae

catfish

-

x

x

-

Lutjanidae

snappers

-

-

-

-

Moronidae

temperate basses

-

-

x

-

Osmeridae

smelts

-

-

-

x

Percidae

perch

-

-

x

x

Pleuronectidae

flounders

-

x

-

-

Pleuronectiformes

flatfishes

x

-

-

-

Sciaenidae

drums and croakers

x

x

x

-

Penaeidae

penaeid shrimp

x

-

-

-

Portunidae

swimming crabs

x

-

-

-

No entry has been denoted by “-”.

IM&E are more of a concern at nuclear power plants that withdraw large volumes of water at
higher velocities. In general, this means that plants with once-through cooling water intake
systems impinge and entrain more organisms than plants with closed-cycle cooling systems,
such as cooling towers, because the former require more water to operate. The Palisades plant
(no longer operating), which lies on Lake Michigan on the Michigan coast, demonstrates this
difference. In 1972, the plant began operating with a once-through cooling system. In 1976, the
plant transitioned to a closed-cycle system after cooling towers were constructed. An
impingement study found that with the once-through cooling system, Palisades withdrew
400,000 gpm and impinged 654,000 fish annually (Consumers Energy Company and Nuclear
Management Company 2001 as cited in the 2013 LR GEIS). Once cooling towers were
installed, the plant withdrew only 78,000 gpm, and impingement dropped to 7,200 fish per year.
Impingement risk is also related to a fish’s ability to avoid the flow of water into the cooling water
intake system. Fish swimming speeds are typically characterized as burst, prolonged, or
sustained. Burst speeds are the highest speeds a fish can attain over very short periods of time
(typically less than 20 seconds). Burst speeds are exhibited when an individual is capturing
prey, avoiding a predator, or negotiating high water velocities, such as those associated with
riffles and eddies in a fast-flowing river or the draw of a power plant’s intake. Sustained speeds
are low speeds fish can maintain indefinitely without fatigue. These speeds are observed during
routine activities, including foraging, holding, and schooling. Prolonged (or critical) speeds are
those of intermediate endurance that a fish could endure for approximately 20 to 30 minutes
before ending in fatigue. If a species’ reported swimming ability indicates that individuals can

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typically swim faster than a nuclear power plant’s intake velocity, the species would exhibit a low
likelihood of being impinged. Certain species may not be capable of maintaining a sustained
speed that would allow escape from an intake velocity, but an individual could swim in a burst to
avoid impingement. Many fish can avoid becoming impinged when intake velocities are less
than 0.5 feet per second (fps) (0.15 meters per second [m/s]). As discussed below, the EPA has
established this rate as one of the impingement mortality CWA Section 316(b) compliance
options for existing facilities.
At the Turkey Point plant in Florida, the NRC found that all fish in the CCS would be susceptible
to impingement due to the 4.5 fps (1.4 m/s) intake velocity (NRC 2019c). Documented burst
speeds of the three known species in the canal system—sheepshead minnow
(Cyprinodon variegatus), sailfin molly (Poecilia latipinna), and eastern mosquitofish
(Gambusia holbrooki)—were all significantly less than this value. Depending on the ecosystem
of the source water, however, fish may be capable of navigating much higher flows than 0.5 fps
(0.1–5 m/s) because the environment they live in requires this capacity. For instance,
unimpounded rivers can flow at several feet per second during high seasonal flows. Fish and
other aquatic organisms in these rivers are likely already navigating waters of higher velocities
than the draw of a cooling water intake system, and this physiological capability of local
populations reduces the risk of impingement.
Intake velocities and swimming ability is not relevant to entrainment because early life stages of
fish and other organisms susceptible to entrainment are either not motile or are semi-motile.
Therefore, all organisms in the water column from which a cooling water intake structure draws
water are susceptible to entrainment. However, some nuclear power plants seasonally reduce
water consumption during periods of high entrainment. Several nuclear power plants operate a
once-through cooling system but have helper cooling towers that are seasonally operated to
reduce thermal load to the receiving waterbody, reduce entrainment during peak spawning
periods, or reduce consumptive water use during periods of low river flow. These seasonal
reductions are often conditions of NPDES permits or agreements made with regional water
quality control boards. Plants with helper cooling towers include the Dresden plant on the
Kankakee River in Illinois, Browns Ferry plant on the Tennessee River in Alabama, Monticello
Nuclear Generating Plant (Monticello) and Prairie Island plant on the Mississippi River in
Minnesota, Peach Bottom plant on Conowingo Pond in Pennsylvania, and Sequoyah plant on
the Chickamauga Reservoir in Tennessee.
IM&E often vary by season. Impingement can occur year-round, but it is often correlated with
seasonal movements and migrations of species, especially for plants located on estuaries and
bays. Entrainment is primarily of concern in the spring and summer when many species spawn
and early life stages of fish are present in the water column. For instance, Surry withdraws
cooling water from the James River in Virginia at the transitional zone between the tidally
influenced freshwater river upstream and the saline estuary downstream. Because of its
location, freshwater, estuarine, and marine fishes may all be found in the river near the plant,
depending on season and salinity conditions. The local finfish community includes permanent
residents that occur year-round and diadromous species that pass through the region
seasonally during migrations to and from spawning grounds. Therefore, impingement frequency
for many migrating species is expected to be highly seasonal. Impingement studies confirm this
assumption. During impingement studies conducted at the plant, spot (Leiostomus xanthurus)
and Atlantic menhaden (Brevvortia tyrannus) impingement was highest in summer and early fall,
which correlates with the seasonal movements of juveniles between oceanic spawning grounds,
inshore nurseries, and overwintering areas (NRC 2020f). In contrast, white perch
(Morone americana), blueback herring, and threadfin shad were primarily impinged in late fall

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and winter. Bay anchovy (Anchoa mitchilli) and Atlantic croaker (Micropogonias undulatus)
impingement was prominent only in the spring. The catfishes (Ictalurus and Pylodictis species),
which are resident species, were impinged at relatively constant levels throughout the year. At
Point Beach plant on Lake Michigan in Wisconsin, approximately 96 percent of estimated
impingement occurs from late April through early August, which mirrors the annual die-offs of
alewife in the lake as well as the species’ offshore/onshore movement patterns (NextEra Energy
2021; NRC 2021f). Alewife accounts for more than 99 percent of impingement at this plant
annually. Entrainment is also highly seasonal at Point Beach. Several studies have observed
that fish eggs and larvae are entrained in highest densities from early June to early August.
Rainbow smelt (Osmerus mordax) dominate the early sample period, while burbot (Lota lota)
become more abundant in the mid-season, correlating with these species’ spawning habits
(NextEra Energy 2021; NRC 2021f). The 2013 LR GEIS discusses several additional examples
of seasonal impingement at the Quad Cities plant in Illinois, McGuire plant in North Carolina,
and Summer plant in South Carolina.
If a facility withdraws cooling water farther from shore, at greater depths, or otherwise in a less
biologically productive area of the source water, IM&E may be less than if the facility were to
withdraw water from elsewhere in the waterbody. In many waterbodies, cooling water
withdrawal from shoreline locations can result in greater environmental impacts because
shoreline areas are typically the most biologically productive waters and contain a high density
of early life-stage organisms. The lowest potential for impingement and entrainment is often at
far offshore locations at distances of several hundred feet (79 FR 48300). Although offshore
areas may exhibit a lower density of organisms, the species found will also change as a function
of the distance of the intake from the shoreline and the depth of the intake within the water
column. Thus, the assemblage of impingeable and entrainable organisms, in addition to the
sheer number of organisms, changes with distance from the shoreline. At the Point Beach plant,
fish and other aquatic organisms in the source water first interact with the cooling water intake
system at an intake crib that lies 1,750 ft (533 m) offshore at an approximate depth of 22 ft (7 m)
below the lake’s surface (NRC 2021f). A study conducted in 2007 determined that the offshore
location of Point Beach’s intake reduces impingement by 79 percent and entrainment by
89 percent relative to if the intake were to be located in the shallow nearshore waters of Lake
Michigan (NextEra Energy 2021). At the LaSalle plant on the Illinois River in Illinois, estimated
annual entrainment is 38 million organisms (EA Engineering 2015). However, researchers
estimated that this rate is 28 to 38 percent of annual entrainment at the Dresden plant, which is
located downstream at the confluence of the Kankakee and Illinois Rivers in a more biologically
rich region.
Some nuclear power plants have exclusion technologies that divert organisms that would have
otherwise been subject to impingement and entrainment away from the intake. Collection and
return technologies allow organisms to be impinged, but these technologies collect and return
the organisms to the source water, thereby reducing or preventing impingement mortality.
Collection and return technologies do not affect entrainment. The Surry plant’s cooling water
intake system includes a fish return system that returns impinged fish to the James River. The
system includes continuously rotating Ristroph traveling screens, low-pressure spray washes,
steel fish buckets, and a return trough. Researchers determined that 56 of the 70 taxa impinged
at Surry during a 2015–2016 study exhibited an impingement survival rate of 70 percent or
greater (NRC 2020f). This included many species that the EPA defines as fragile, such as
Atlantic menhaden and gizzard shad. The NRC staff calculated impingement mortality for all
taxa (fragile and nonfragile) at Surry to be between 2.03 percent (using 2015–2016 data) and
5.60 percent (1974–1978 data), which demonstrates the effectiveness of the fish return system
(NRC 2020f). The Columbia plant, which lies on the Columbia River in Washington, is equipped

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with cylindrical intake screens, which could hydraulically deflect fish and stimulate the fish’s
behavior to avoid the intake screens. Thus, there is low likelihood of impingement and
entrainment in nearly all river flow and direction cases due to the generally high ratio of
tangential (sweeping) flow to normal (approach) flow toward the screens (Anchor QEA,
LLC 2020).
Impinged organisms that are returned to the source waterbody may experience stunning,
disorientation, or injury. These sublethal effects can subsequently affect an organism’s
susceptibility to predation, parasitism, or disease. The 1996 and 2013 LR GEISs reported that
neither scientific literature reviews nor consultations with agencies or utilities yielded clear
evidence of sublethal effects on fish or finfish resulting in noticeable increases in impinged
organisms’ susceptibility to predation, parasitism, or disease. Since the publication of the
2013 LR GEIS, the NRC has determined that the impacts of impingement and entrainment at
four nuclear power plants with once-through cooling systems or cooling ponds could be SMALL
to MODERATE (2 plants), MODERATE (1 plant), or SMALL to LARGE (1 plant) during the
license renewal term (see Table 4.6-4). However, increased susceptibility to predation,
parasitism, or disease or predation resulting from impingement was not found to be an issue in
any of these reviews. The available information indicates that these secondary impacts of
impingement are not expected to be of concern during initial LR or SLR terms at any nuclear
power plants. As stated earlier in this section, because entrainable organisms generally consist
of fragile life stages, all entrained organisms are assumed to die (79 FR 48300). Therefore,
sublethal effects of entrainment do not apply.
At some nuclear power plants, marine reptiles and marine mammals can be impinged or
entrained by the cooling water intake system in addition to finfish and shellfish. For instance, at
the Salem plant in New Jersey, sea turtles from the Delaware Estuary can become impinged in
the trash bars. When discovered, plant personnel remove the sea turtles and assess their
condition. Live, healthy turtles are returned to the estuary. At St. Lucie Nuclear Plant (St. Lucie)
in Florida, sea turtles and other marine organisms can enter one of three intake pipes located in
the Atlantic Ocean and be drawn into the intake canal where they become entrapped. Because
marine organisms that enter the intake canal cannot return to the ocean on their own, divers
capture sea turtles, transport them over the beach dunes, and release them back to the ocean.
Injured or sick sea turtles are sent to a rehabilitation facility. Sea turtle impingement or
entrainment has also occurred at the Diablo Canyon plant and San Onofre plant (no longer
operating) on the Pacific Ocean in California; Oyster Creek plant (no longer operating) on
Barnegat Bay in New Jersey; Brunswick Steam Electric Plant (Brunswick) on the Cape Fear
River estuary in Virginia, and Crystal River Nuclear Power Plant (Crystal River) (no longer
operating) on the Gulf Coast in Florida. Sea turtles are federally protected under the ESA.
Sections 3.6.3 and 4.6.1.3 address these species.
At Seabrook on the Gulf of Main in New Hampshire, harbor (Phoca vitulina), gray
(Halichoerus grypus), harp (Pagophilus groenlandicus), and hooded (Cystophora cristata) seals
have been entrained into the intake tunnels. From 1993 through 1998, approximately 55 seals
drowned from entrainment into the intake tunnels. In 1999, following coordination with NMFS,
the plant installed seal deterrents that included vertical barriers on each of the three intake
structures that reduced the vertical spacing of the bars to less than 5 in. (13 cm) (NRC 2015b).
Since installment of these barriers, no seals have been entrained at Seabrook (NRC 2015b). At
Diablo Canyon, several California sea lions (Zalophus californianus) and harbor seals and one
elephant seal (Mirounga angustirostris) have become entrapped in the cooling water intake
system. All of the California sea lions and harbor seals were discovered dead against the intake
trash bars or in one of the traveling screen forebays, and plant personnel removed the

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carcasses from the intake structure in accordance with Diablo Canyon’s Marine Mammal
Protection Act letter of authorization (PG&E 2007, PG&E 2008a, PG&E 2008c, PG&E 2008d,
PG&E 2009a, PG&E 2009b, PG&E 2014a, PG&E 2014b, PG&E 2015a, PG&E 2015b,
PG&E 2015c). Most of these animals were in some state of decomposition, and their deaths
were not attributed to plant operation. The elephant seal, a juvenile, was discovered in a recess
between concrete tri-bars on the intake cover breakwater; plant personnel successfully returned
it to the intake cove (PG&E 2008b). There have been no reported marine mammal
impingements or strandings at Diablo Canyon since 2015.
Table 4.6-4 summarizes the results of the NRC’s impingement and entrainment analyses for
initial LR and SLR environmental reviews conducted since the 2013 LR GEIS was published.
The 2013 LR GEIS discusses impingement and entrainment findings from reviews prior to 2013
and includes many additional examples relevant to this issue.
Table 4.6-4

Results of NRC Impingement and Entrainment Analyses at Nuclear Power
Plants, 2013–Present

Nuclear Power
Plant

Cooling System Type

Cooling Water Source

Impingement and
Entrainment Conclusion

Braidwood

Cooling pond

Constructed cooling pond
SMALL to MODERATE(a)
with makeup water from the
Kankakee River

Byron

Cooling towers (ND)

Rock River

SMALL

Callaway

Cooling towers (ND)

Missouri River

SMALL

Davis-Besse

Cooling towers (ND)

Lake Erie

SMALL

Fermi

Cooling towers (ND)

Lake Erie

SMALL

Grand Gulf

Cooling towers (ND)

Mississippi River

SMALL

Indian Point(b)

Once-through

Hudson River

MODERATE(c)

LaSalle

Cooling pond

Constructed cooling pond
with makeup from the
Illinois River

SMALL

Limerick

Cooling towers (ND)

Schuylkill River

SMALL

North Anna(d)

Cooling pond

Lake Anna

SMALL

Peach

Bottom(d)

Hybrid: once-through (Unit
Conowingo Pond
2); once-through and cooling
towers (MD) (Unit 3)

SMALL

Point Beach(d)

Once-through

Lake Michigan

SMALL

River Bend

Cooling towers (MD)

Mississippi River

SMALL

Seabrook

Once-through

Gulf of Maine

SMALL to LARGE(e)

Sequoyah

Hybrid: once-through and
cooling towers (ND)

Chickamauga Reservoir

SMALL

South Texas

Cooling pond

Constructed cooling
reservoir with makeup
water from the Colorado
River

SMALL

Surry(b)

Once-through

James River

SMALL

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Nuclear Power
Plant
Turkey Point(b)

Cooling System Type
Cooling pond

Cooling Water Source
Constructed CCS with
makeup from the Upper
Floridan aquifer

Waterford

Once-through

Mississippi River

Impingement and
Entrainment Conclusion
SMALL to MODERATE(f)

SMALL

CCS = cooling canal system; MD = mechanical draft; ND = natural draft.
(a) Impingement and entrainment effects would be SMALL for aquatic resources in the Kankakee River as a whole.
Impacts on cyprinids, especially uncommon cyprinids (pallid shiner [Notropis amnis], mimic shiner [N. volucellus],
and ghost shiner [N. buchanani]); darters; and Percina species would be MODERATE. The NRC cannot make a
determination on the impact of impingement and entrainment on the aquatic resources in the cooling pond
because no studies exist on impingement and entrainment at the lake screen house.
(b) This evaluation was a part of a review that supplemented the NRC's final SEIS.
(c) While most aquatic organisms would experience SMALL effects, some would experience noticeable effects as a
result of impingement and entrainment. These organisms include blueback herring, rainbow smelt, and
hogchoker (Trinectes maculatus).
(d) This review evaluated a subsequent license renewal term.
(e) Impingement and entrainment would be SMALL for most aquatic resources in the Gulf of Maine. Impacts on
winter flounder would be LARGE because monitoring data indicate that the abundance of winter flounder has
decreased to a greater and observable extent near the Seabrook plant compared to reference sites. The local
decrease suggests that local subpopulations of this species have been destabilized through operation of
Seabrook’s cooling water system.
(f) Impingement and entrainment effects would be SMALL to MODERATE for aquatic organisms of the CCS.
Impingement and entrainment do not apply to aquatic organisms in Biscayne Bay and connected waterbodies
(e.g., Card Sound, the Atlantic Ocean) because these organisms never interact with the Turkey Point intake
structure.
Sources: NRC 2013b, NRC 2014d, NRC 2014e, NRC 2014f, NRC 2015b, NRC 2015c, NRC 2015d, NRC 2015e,
NRC 2015f, NRC 2016c, NRC 2016d, NRC 2018c, NRC 2018e, NRC 2020f, NRC 2020g, NRC 2021f, NRC 2021g.

IM&E of aquatic organisms would continue throughout the license renewal term for any
operating nuclear power plant. The effects of IM&E are discussed later in this section as three
issues:
• impingement mortality and entrainment of aquatic organisms (plants with once-through
cooling systems or cooling ponds)
• impingement mortality and entrainment of aquatic organisms (plants with cooling towers)
• entrainment of phytoplankton and zooplankton
A number of mitigative measures can reduce the effects of IM&E. These include withdrawal of
water at rates of 0.5 fps (0.15 m/s) or less, seasonal reductions in intake volume during peak
periods of entrainment; locating the cooling water intake system in a less biological productive
area of the source water, and use of exclusion technologies or fish return systems. Additionally,
Section 316(b) of the CWA addresses these effects and requires that cooling water intake
structures of regulated facilities must reflect the best technology available (BTA) for minimizing
IM&E, as discussed below.
Clean Water Act Section 316(b) Requirements for Minimizing IM&E at Existing Facilities
Section 316(b) of the CWA addresses the adverse environmental impacts caused by the intake
of cooling water from waters of the United States. This section of the CWA grants the EPA the
authority to regulate cooling water intake structures to minimize adverse impacts on the aquatic
environment. In 2014, pursuant to CWA Section 316(b), the EPA issued regulations for existing
facilities at 40 CFR 122 and 40 CFR 125, Subpart J (79 FR 48300). Existing facilities include

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power generation and manufacturing facilities that are not new facilities as defined at
40 CFR 125.83 and that withdraw more than 2 Mgd of water from waters of the United States
and use at least 25 percent of the water they withdraw exclusively for cooling purposes.
Under the CWA Section 316(b) regulations, the location, design, construction, and capacity of
cooling water intake structures of regulated facilities must reflect the BTA for minimizing IM&E.
The EPA, or authorized States and Tribes, impose BTA requirements through NPDES
permitting programs.
With respect to impingement mortality, the BTA standard requires that existing facilities comply
with one of the following seven alternatives (40 CFR 125.94(c)):
1. operate a closed-cycle recirculating system as defined at 40 CFR 125.92(c)
2. operate a cooling water intake structure that has a maximum through-screen design intake
velocity of 0.5 fps (0.15 m/s)
3. operate a cooling water intake structure that has a maximum through-screen intake velocity
of 0.5 fps (0.15 m/s)
4. operate an offshore velocity cap as defined at 40 CFR 125.92 that is installed before
October 14, 2014
5. operate a modified traveling screen that the NPDES Permit Director determines meets the
definition at 40 CFR 125.92(s) and that the NPDES Permit Director determines is the BTA
for impingement reduction at the site
6. operate any other combination of technologies, management practices, and operational
measures that the NPDES Permit Director determines is the BTA for impingement reduction
7. achieve the specified impingement mortality performance standard
Options 1, 2, and 4 above are essentially preapproved technologies requiring no demonstration
or only a minimal demonstration that the flow reduction and control measures are functioning as
EPA envisioned. Options 3, 5, and 6 require that more detailed information be submitted to the
permitting authority before the permitting authority may specify it as BTA for a given facility.
Under Option 7, the permitting authority may also review plant-specific data and conclude that a
de minimis rate of impingement exists and, therefore, no additional controls are warranted to
meet the BTA impingement mortality standard.
With respect to entrainment, the CWA Section 316(b) regulations do not prescribe a single
nationally applicable entrainment performance standard because the EPA did not identify a
technology for reducing entrainment that is effective, widely available, feasible, and does not
lead to unacceptable non-water quality impacts. Instead, the permitting authority must establish
the BTA entrainment requirement for each facility on a plant-specific basis. In establishing plantspecific requirements, the regulations direct the permitting authority to consider the following
factors (40 CFR 125.98(f)(2)):
• the numbers and types of organisms entrained, including, specifically, the numbers and
species (or lowest taxonomic classification possible) of federally listed, threatened and
endangered species, and designated critical habitat (e.g., prey base)
• the impact of changes in particulate emissions or other pollutants associated with entrainment
technologies
• the land availability inasmuch as it relates to the feasibility of entrainment technology

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• the remaining useful plant life
• the quantified and qualitative social benefits and costs of available entrainment technologies
when such information about both benefits and costs is of sufficient rigor to make a decision
In support of entrainment BTA determinations, facilities must conduct plant-specific studies and
provide data to the permitting authority to aid in its determination of whether plant-specific
controls would be required to reduce entrainment and which controls, if any, would be
necessary.
The NRC considers whether nuclear power plants have implemented BTA when assessing the
impacts of IM&E, as discussed below.
Thermal Impacts
Thermal impacts associated with thermal effluent discharges from cooling water systems
include acute effects, sublethal effects, and community-level effects. Acute effects cause
immediate or latent death of aquatic organisms. Sublethal effects include stunning,
disorientation, or injury that affect an organism’s fitness, behavior, or susceptibility to predation,
parasitism, or disease. Community-level effects can include reduced habitat availability or
quality and reduced species diversity.
The primary thermal impact of concern at operating nuclear power plants is the acute effect of
heat shock. Heat shock occurs when water temperatures meet or exceed the thermal tolerance
of a species for some duration of exposure. In most situations, fish can move out of an area that
exceeds their thermal tolerance limits, although some aquatic species lack such mobility. Heat
shock is typically observable only for finfish, particularly those that float when dead. In addition
to heat shock, thermal plumes resulting from thermal effluents can create barriers to fish
passage, which is of particular concern for migratory species. Thermal effluents are not as likely
to affect shellfish because plumes tend to rise to the surface of the water and shellfish typically
inhabit the benthic zone. In addition to having direct effects on aquatic organisms, thermal
plumes can also reduce the available aquatic habitat or alter habitat characteristics in a manner
that results in cascading effects on the local aquatic community.
The magnitude of thermal impacts on the aquatic environment depends on the plant-specific
characteristics of the cooling system as well as the characteristics of the local aquatic
community. Relevant plant characteristics include discharge location, temperature of the effluent
when it enters the receiving waterbody, thermal plume characteristics, and any technologies
that assist in mixing or otherwise reducing thermal impacts. Relevant characteristics of the
aquatic community include the species present in the environment, life history characteristics,
population abundances and distributions, special species statuses and designations, and
regional management objectives, as well as the characteristics of the receiving water, such as
ambient temperatures and typical flow of water near the discharge point.
Thermal effects are more of a concern at nuclear power plants that discharge large volumes of
heated effluents. In general, this means that plants with once-through cooling water intake
systems or cooling ponds have a larger thermal impact than plants with closed-cycle cooling
systems, such as cooling towers, because the former require more water to operate.
Fish kills are an acute thermal effect that is typically observed only at plants with cooling ponds.
This may be because heat dissipation of the thermal effluent is limited by the size of the
receiving waterbody and because aquatic organisms in cooling ponds are unable to escape
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thermal plumes. Many freshwater fish, such as those species that inhabit cooling ponds,
experience thermal stress and can die when they encounter water temperatures at or above
95°F (35°C). Fish kills tend to occur when water temperatures rise above this level for some
prolonged period of time and fish are unable to tolerate the higher temperatures or cannot
retreat into cooler waters. Fish that experience thermal effects within the region of a receiving
waterbody that is thermally affected by a nuclear power plant’s effluent discharge are
experiencing effects that are, at least in part, attributable to plant operation.
Fish kills have been observed in the summer months at several midwestern plants with cooling
ponds, including the Braidwood and LaSalle plants in Illinois. Such events tend to be correlated
with periods of high ambient air temperatures, low winds, and high humidity. For instance, six
reportable fish kill events occurred in the Braidwood cooling pond from 2001 through 2015. The
fish kill events, which occurred in July 2001, August 2001, June 2005, August 2007, June 2009,
and July 2012, primarily affected threadfin shad and gizzard shad, although bass, catfish, carp,
and other game fish were also affected (NRC 2015d). Reported peak temperatures in the
cooling pond during these events ranged from 98.4°F (36.9°C) to over 100°F (37.8°C), and
each event resulted in the death of between 700 to as many as 10,000 fish. During the July
2012 event, cooling pond temperatures exceeded 100°F (37.8°C), which resulted in the death of
approximately 3,000 gizzard shad and 100 bass, catfish, and carp. This event coincided with the
NRC's granting of Enforcement Discretion to allow the Braidwood plant to continue to operate
above the technical specification limit of less than or equal to 100°F (37.8°C) (NRC 2021b). At
the LaSalle plant, Exelon has reported four fish kill events since 2001. The events occurred in
July 2001, June 2005, June 2009, and August 2010, and primarily affected gizzard shad. The
Illinois Department of Natural Resources identified other dead fish to include carp (Cyprinus
carpio), smallmouth buffalo (Ictiobus bubalus), freshwater drum (Aplodinotus grunniens),
channel catfish (Ictalurus punctatus), striped bass hybrid (Morone chrysops x M. saxatilis),
smallmouth bass (Micropterus dolomieu), walleye (Sander vitreus), bluegill (Lepomis
macrochirus), white bass (Morone chrysops), yellow bullhead catfish (Ameiurus natalis), and
yellow bass (M. mississippiensis) (NRC 2016d). The temperature in the cooling pond during
these events ranged from 93°F (33.9°C) to 101°F (38.3°C), and each event resulted in the
death of approximately 1,500 to 94,500 fish (NRC 2021a).
Fish kill events have rarely been reported at nuclear power plants without cooling ponds. Two
fish kills occurred at Pilgrim Nuclear Power Station (Pilgrim) on Cape Cod in Massachusetts in
the 1970s, but no such events have been reported since then. In 1975, about 3,000 Atlantic
menhaden (Brevoortia tyrannus) were killed, and in 1978, about 2,300 Clupeidae (herrings,
shads, sardines, and menhadens) were killed (NRC 2007c). After several fish kills at the
Summer plant on the Monticello Reservoir in South Carolina in the 1980s, the licensee modified
the discharge to reduce the likelihood of future fish kills by removing a hump in the discharge
canal, dredging the canal, and limiting reservoir drawdowns (NRC 2004b).
Thermal effluents of nuclear power plants can also contribute to sublethal effects, such as the
stunning or disorientation of fish and other aquatic organisms exposed to elevated water
temperatures. Such effects can increase the susceptibility of affected individuals to predation.
Schubel et al. (1977) concluded that the exposure of blueback herring, American shad, and
striped bass (Morone saxatilis) larvae to an excess of 59°F (15°C) would significantly increase
their vulnerability to predation. However, such effects are difficult to prove from field studies.
The 1996 and 2013 LR GEISs did not report such effects, and no license renewal environmental
reviews since the publication of the 2013 LR GEIS have identified this issue to be of concern.

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Aquatic organisms overwintering within thermal plumes can also experience chronic malnutrition
(Hall et al. 1978). Thermal discharges can also increase the susceptibility of fish to disease and
parasites because of a combination of increased density of fish within the thermal plume
(potentially leading to an increased risk of exposure to infectious diseases or other stresses)
and the proliferation of many diseases and parasites in warmer water. Examples of other
temperature-related impacts on aquatic resources could include the loss of smolt characteristics
in salmon (McCormick et al. 1999) and premature spawning (Hall et al. 1978). However, none of
these effects have been specifically linked to operation of any nuclear power plants.
Community-level effects of thermal effluent discharges can include reduced habitat availability
or quality and reduced species diversity. These effects are typically localized and often only
affect certain microhabitats, species, or taxa groups. For instance, at the Peach Bottom plant,
which discharges to Conowingo Pond in Pennsylvania, the NRC found that thermal effluents
would result in no noticeable effect on the aquatic community during most of the year and in
most areas of the cooling pond (NRC 2020g). However, during summer months, thermal studies
indicated that a narrow 12 ac (4.9 ha) band of shallow water habitat downstream of the
discharge canal exhibited short-term, observable changes, including reduced macroinvertebrate
community health and lower fish diversity. The NRC determined that these impacts would likely
continue during the license renewal term because the characteristics of thermal discharges
would remain the same as those during the initial period of operation. As a result, aquatic
organisms in this shallow water habitat would seasonally experience thermal stress and might
exhibit avoidance behaviors.
Table 4.6-5 summarizes the results of the NRC’s thermal analyses for initial LR and SLR
environmental reviews conducted since the publication of the 2013 LR GEIS. The
2013 LR GEIS discusses thermal findings from reviews prior to 2013 and includes many
additional examples relevant to this issue.
Table 4.6-5

Results of NRC Thermal Analyses at Nuclear Power Plants, 2013–Present

Nuclear Power
Plant
Cooling System Type
Braidwood
Cooling pond

Cooling Water Source
Constructed cooling pond
with makeup water from
the Kankakee River

Thermal Impact
Conclusion
SMALL to MODERATE(a)

Byron

Cooling towers (ND)

Rock River

SMALL

Callaway

Cooling towers (ND)

Missouri River

SMALL

Davis-Besse

Cooling towers (ND)

Lake Erie

SMALL

Fermi

Cooling towers (ND)

Lake Erie

SMALL

Grand Gulf

Cooling towers (ND)

Mississippi River

SMALL

Indian Point(b)

Once-through

Hudson River

SMALL

LaSalle

Cooling pond

Constructed cooling pond
with makeup from the
Illinois River

SMALL to MODERATE(c)

Limerick

Cooling towers (ND)

Schuylkill River

SMALL

North Anna(d)

Cooling pond

Lake Anna

SMALL

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Nuclear Power
Plant
Cooling System Type
(d)
Peach Bottom
Hybrid: once-through
(Unit 2); once-through and
cooling towers (MD)
(Unit 3)

Cooling Water Source
Conowingo Pond

Thermal Impact
Conclusion
SMALL to MODERATE(e)

Point Beach(d)

Once-through

Lake Michigan

SMALL

River Bend

Cooling towers (MD)

Mississippi River

SMALL

Seabrook

Once-through

Gulf of Maine

SMALL

Sequoyah

Hybrid: once-through and
cooling towers (ND)

Chickamauga Reservoir

SMALL

South Texas

Cooling pond

Constructed cooling
reservoir with makeup
water from the Colorado
River

SMALL

Surry(b)

Once-through

James River

SMALL

Turkey Point(b)

Cooling pond

Constructed CCS with
makeup from the Upper
Floridan aquifer

SMALL to MODERATE(f)

Waterford

Once-through

Mississippi River

SMALL

CCS = cooling canal system; MD = mechanical draft; ND = natural draft.
(a) Thermal impacts associated with license renewal would result in SMALL impacts on aquatic resources in the
Kankakee River and SMALL to MODERATE impacts on aquatic resources in the cooling pond. MODERATE
impacts would primarily be experienced by gizzard shad and other non-stocked and low-heat tolerant species.
(b) This evaluation was a part of a review that supplemented the NRC's final SEIS.
(c) Thermal impacts would be SMALL for all aquatic resources in the Illinois River and SMALL for aquatic resources
in the cooling pond, except for gizzard shad and threadfin shad. Gizzard shad and threadfin shad would
experience MODERATE thermal impacts in the cooling pond.
(d) This review evaluated a subsequent license renewal term.
(e) During most of the year and in most areas of Conowingo Pond, the thermal effluent would not noticeably affect
the aquatic community and its impact would be SMALL. However, during summer months, a narrow 12 ac
(4.9 ha) band of shallow water habitat downstream of the discharge canal would exhibit short-term, observable
changes, including reduced macroinvertebrate community health and lower fish diversity. Seasonal impacts in
this region would be MODERATE because water temperatures would result in thermal stress and avoidance
behaviors.
(f) Thermal impacts would be SMALL to MODERATE for aquatic organisms because the thermal effluent may result
in some degree of physiological stress on cooling canal system aquatic organisms. However, thermal impacts
are unlikely to create effects great enough to destabilize important attributes of the aquatic environment over the
course of the subsequent license renewal term because the cooling canal system aquatic community is
composed of species that exhibit no unique ecological value or niche and have no commercial or recreational
value. Aquatic organisms inhabiting Biscayne Bay are not subject to thermal impacts associated with Turkey
Point because there are no surface water connections that allow flow between these waters and the cooling
canal system.
Sources: NRC 2013b, NRC 2014d, NRC 2014e, NRC 2014f, NRC 2015b, NRC 2015c, NRC 2015d, NRC 2015e,
NRC 2015f, NRC 2016c, NRC 2016d, NRC 2018c, NRC 2018e, NRC 2020f, NRC 2020g, NRC 2021f, NRC 2021g.

Thermal effluent discharges would continue throughout the license renewal term for any
operating nuclear power plant. The effects of thermal effluent discharges are discussed below
as three issues:

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• effects of thermal effluents on aquatic organisms (plants with once-through cooling systems
or cooling ponds)
• effects of thermal effluents on aquatic organisms (plants with cooling towers)
• infrequently reported effects of thermal effluents
Several mitigative measures can reduce thermal effects. These include routing effluent through
discharge canals or settling ponds that dissipate heat before the effluent enters the receiving
waterbody and using high-velocity discharge jets that disperse thermal effluents and promote
rapid mixing. Additionally, Section 316(a) of the CWA addresses thermal effects and requires
that facilities operate under effluents limitations that assure the protection and propagation of a
balanced, indigenous population of shellfish, fish, and wildlife in and on the receiving body of
water, as discussed below.
Clean Water Act Section 316(a) Requirements for Point Source Discharges
CWA Section 316(a) (79 FR 48300) addresses the adverse environmental impacts associated
with thermal discharges into waters of the United States. Under this section of the Act, the EPA,
or authorized States and Tribes, establish thermal surface water quality criteria for waters of the
United States within their jurisdiction. States have established standards that incorporate
several different types of temperature criteria. These criteria include the following:
• Maximum temperature limit: a limit on the maximum temperature in a waterbody. This is the
core of temperature standards in nearly every State.
• Temperature rise above ambient: a limit on the temperature rise above ambient or natural
conditions. This criterion is common among states and is usually specific to habitat type,
seasons, designated uses, or specific waterbody.
• Abrupt temperature change: a restriction in the rate of temperature change over a brief period
of time to protect aquatic life from heat shock that can result in lethal or sub-lethal effects.
• Diel and seasonal variability: an allowance for varied temperature depending on the time of
day or season. This type of standard is usually narrative rather than quantitative.
• Species diversity: a standard that ensures that the aquatic ecosystem continues to provide an
array of microhabitats with a range of temperatures to promote species and spatial diversity.
This type of standard is usually narrative.
• Other criteria: other types of temperature criteria have been established in certain states. For
instance, California has established a limit on the difference between the discharge
temperature and the receiving waterbody temperature. Florida maintains a maximum
temperature of the discharge itself.
Additionally, water quality criteria typically address thermal mixing zones, which the EPA (2017)
defines as “a limited area or volume of water where initial dilution of a discharge takes place and
where numeric water quality criteria can be exceeded but acutely toxic conditions are
prevented.” Mixing zones should provide a continuous zone of passage that meets water quality
criteria for free-swimming and drifting organisms and that prevents impairment of critical
resource areas. An example of State standards where the mixing zone is specified is in Illinois,
where the specified temperature criteria must be met outside the mixing zone, defined as no
greater than a circle with a radius of 1,000 ft (305 m) or equivalent simple shape.

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Under CWA Section 316(a), the EPA, or authorized States and Tribes, also have the authority
to impose alternative, less-stringent, facility-specific effluent limits (called “variances”) on the
thermal component of individual point source discharges. To be eligible, regulated facilities must
demonstrate, to the satisfaction of the NPDES permitting authority, that facility-specific effluent
limitations will assure the protection and propagation of a balanced, indigenous population of
shellfish, fish, and wildlife in and on the receiving body of water. CWA Section 316(a) variances
are valid for the term of the NPDES permit (i.e., 5 years). Facilities must reapply for variances
with each NPDES permit renewal application. The EPA has issued regulations under CWA
Section 316(a) at 40 CFR 125, Subpart H.
The NRC considers whether nuclear power plants have valid CWA 316(a) variances when
assessing the impacts of thermal discharges on aquatic organisms, as discussed later in this
section (see Section 4.6.1.2.4).
4.6.1.2.1

Impingement Mortality and Entrainment of Aquatic Organisms (Plants with
Once-Through Cooling Systems or Cooling Ponds)

This issue pertains to IM&E of finfish and shellfish at nuclear power plants with once-through
cooling systems and cooling ponds during an initial LR or SLR term. This includes plants with
helper cooling towers that are seasonally operated to reduce thermal load to the receiving
waterbody, reduce entrainment during peak spawning periods, or reduce consumptive water
use during periods of low river flow. IM&E of finfish and shellfish at nuclear power plants with
cooling towers operated in a fully closed-cycle mode is addressed in Section 4.6.1.2.2.
Entrainment of phytoplankton and zooplankton is addressed in Section 4.6.1.2.3. Impingement
and entrainment of federally protected species subject to interagency consultation, such as sea
turtles and sturgeon, is addressed in Section 4.6.1.3.2.
In the 1996 and 2013 LR GEISs, the NRC determined that the impacts of impingement and
entrainment of aquatic organisms would be SMALL at many nuclear power plants with oncethrough cooling systems or cooling ponds, as well as plants that operate in a hybrid mode
(i.e., once-through cooling with cooling towers that operate intermittently), but that these impacts
could be MODERATE or LARGE at some plants. Therefore, impingement and entrainment were
considered Category 2 issues for these plants. The 1996 LR GEIS addressed impingement and
entrainment as two distinct issues. The 2013 LR GEIS combined the two issues into one issue
titled, “Impingement and entrainment of aquatic organisms (plants with once-through cooling
systems or cooling ponds).”
In this LR GEIS, the NRC refines the title of this issue to include impingement mortality, rather
than simply impingement. This change is consistent with the EPA’s 2014 CWA Section 316(b)
regulations and the EPA’s assessment that impingement reduction technology is available,
feasible, and has been demonstrated to be effective. For example, and as described above,
impingement mortality at the Surry plant is estimated at between 2.03 and 5.60 percent
(NRC 2020f). Therefore, although the plant’s once-through cooling system impinges a large
number of organisms, the highly effective fish return system ensures that the majority of
organisms are returned back to the river unharmed. Additionally, the EPA’s 2014 CWA
Section 316(b) regulations establish BTA standards for impingement mortality based on the fact
that survival is a more appropriate metric for determining environmental impact than simply
looking at total impingement. Survival studies typically take into account latent mortality
associated with stunning, disorientation, or injury. Such effects can result from the injury itself or
from increased susceptibility to predation, parasitism, or disease that results from the sublethal
effects of impingement. Therefore, this LR GEIS also consolidates the impingement component

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of the issue of “Losses from predation, parasitism, and disease among organisms exposed to
sublethal stresses,”11 for plants with once-through cooling systems or cooling ponds into this
issue.
As a result of the 2014 CWA Section 316(b) regulations, nuclear power plants must submit
detailed information about their cooling water intake systems as part of NPDES permit renewal
applications to support the permitting authority in making BTA determinations. Of note, for
existing facilities that withdraw greater than 125 Mgd of water for cooling purposes, 40 CFR
122.21(r)(9) requires these facilities to submit an entrainment characterization study, and
40 CFR 122.21(r)(6) requires these facilities to submit their chosen method(s) of compliance
with the impingement mortality standard, including supporting studies and data for Options
(3), (5), and (6) listed above. In NPDES permits issued since 2014, permitting authorities have
typically included a timeline for submittal of this information as special conditions of the permit,
and the permitting authority has used this information to make final BTA determinations during
the subsequent five-year NPDES permitting cycle. Thus, some nuclear power plants have
received final BTA determinations under the 2014 CWA Section 316(b) regulations. Many
others have submitted the required information and are awaiting final determinations. The NRC
staff expects that most operating nuclear power plants will have final BTA determinations within
the next several years.
When available, the NRC staff relies on the expertise and authority of the NPDES permitting
authority with respect to the impacts of IM&E. Therefore, if the NPDES permitting authority has
made BTA determinations for a nuclear power plant pursuant to CWA Section 316(b) in
accordance with the current regulations at 40 CFR Part 122 and 40 CFR Part 125, which were
promulgated in 2014, and that plant has implemented any associated requirements or those
requirements would be implemented before the license renewal period, then the NRC staff
assumes that adverse impacts on the aquatic environment would be minimized (see
10 CFR 51.10(c); 10 CFR 51.53(c)(3)(ii)(B); 10 CFR 51.71(d)). In such cases, the NRC staff
concludes that the impacts of either impingement mortality, entrainment, or both would be
SMALL over the course of the initial LR or SLR renewal term for these nuclear power plants.
In cases where the NPDES permitting authority has not made BTA determinations, the NRC
staff analyzes the potential impacts of impingement mortality, entrainment, or both using a
weight-of-evidence approach. In this approach, the staff considers multiple lines of evidence to
assess the presence or absence of ecological impairment (i.e., noticeable or detectable impact)
on the aquatic environment. For instance, as its lines of evidence, the staff might consider
characteristics of the cooling water intake system design, the results of impingement and
entrainment studies performed at the facility, and trends in fish and shellfish population
abundance indices. The staff then considers these lines of evidence together to predict the level
of impact (SMALL, MODERATE, or LARGE) that the aquatic environment is likely to experience
over the course of the initial LR or SLR term.
The staff reviewed information from SEISs (for initial LRs and SLRs) completed since
development of the 2013 LR GEIS. In summary, the potential effects of IM&E during an initial
LR or SLR term depend on numerous site-specific factors, including the ecological setting of the
11

The potential for thermal effluents to cause sublethal stresses that increase the susceptibility of aquatic
organisms to predation, parasitism, or disease is evaluated in Section 4.6.1.2.6. The potential for
impingement to cause sublethal stresses at plants with cooling towers is addressed in Section 4.6.1.2.2.
Entrainment would not result in sublethal stresses because entrainable organisms generally consist of
fragile life stages, and all entrained organisms are assumed to die (79 FR 48300).

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plant; the characteristics of the cooling system; and the characteristics of the fish, shellfish, and
other aquatic organisms present in the area (e.g., life history, distribution, population trends,
management objectives, etc.). Additionally, whether the NPDES permitting authority has made
BTA determinations pursuant to CWA Section 316(b) and whether the nuclear power plant has
implemented any associated requirements is also a relevant factor. In general, if the NPDES
permitting authority has made such determinations and the nuclear power plant has
implemented any associated requirements, then the NRC staff assumes that adverse impacts
on the aquatic environment will be minimized and that the impacts of IM&E will be SMALL; if this
is not the case, impacts could be SMALL, MODERATE, or LARGE.
The NRC concludes that the impacts of IM&E of aquatic organisms during the license renewal
term (initial LR or SLR) at nuclear power plants with once-through cooling systems or cooling
ponds could be SMALL, MODERATE, or LARGE. This is a Category 2 issue.
4.6.1.2.2

Impingement Mortality and Entrainment of Aquatic Organisms (Plants with Cooling
Towers)

This issue pertains to IM&E of finfish and shellfish at nuclear power plants with cooling towers
that operate in a fully closed-cycle mode during an initial LR or SLR term. IM&E of finfish and
shellfish at nuclear power plants with once-through cooling systems or cooling ponds is
addressed in Section 4.6.1.2.1. Entrainment of phytoplankton and zooplankton is addressed in
Section 4.6.1.2.3. Impingement and entrainment of federally protected species subject to
interagency consultation, such as sea turtles and sturgeon, are addressed in Section 4.6.1.3.2.
In the 1996 and 2013 LR GEISs, the NRC determined that the impacts of impingement and
entrainment of aquatic organisms would be SMALL at all nuclear power plants with cooling
towers operated in a fully closed-cycle mode. Therefore, impingement and entrainment were
considered Category 1 issues for these plants. The 1996 LR GEIS addressed impingement and
entrainment as two distinct issues. The 2013 LR GEIS combined the two issues into one issue
titled, “Impingement and entrainment of aquatic organisms (plants with cooling towers).” In this
LR GEIS, the NRC refines the title of this issue to include impingement mortality, rather than
simply impingement. This change is consistent with the EPA’s 2014 CWA Section 316(b)
regulations and because assessing survival of impinged organisms is a more appropriate metric
for determining environmental impact than simply looking at total impingement. Survival studies
typically take into account latent mortality associated with stunning, disorientation, or injury.
Such effects can result from the injury itself or from increased susceptibility to predation,
parasitism, or disease that results from the sublethal effects of impingement. Therefore, this
LR GEIS also consolidates the impingement component of the issue of “Losses from predation,
parasitism, and disease among organisms exposed to sublethal stresses,”12 for plants with
cooling towers into this issue.
In the 1996 and 2013 LR GEISs, the NRC found that impingement and entrainment of finfish
and shellfish at plants with cooling towers operated in a fully closed-cycle mode did not result in
noticeable effects on finfish or shellfish populations within source waterbodies, and this impact
12

The potential for thermal effluents to cause sublethal stresses that increase the susceptibility of aquatic
organisms to predation, parasitism, or disease is evaluated in Section 4.6.1.2.6. The potential for
impingement to cause sublethal stresses at plants with once-through cooling systems or cooling ponds is
addressed in Section 4.6.1.2.1. Entrainment would not result in sublethal stresses because entrainable
organisms generally consist of fragile life stages, and all entrained organisms are assumed to die
(79 FR 48300).

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was not expected to be an issue during the license renewal term. This finding was based, in
part, on the lower rates of water withdrawal at plants with cooling towers that operate in a fully
closed-cycle mode. Of the various factors that can influence IM&E, the volume of water
withdrawn by a cooling water intake system relative to the size of the source waterbody appears
to be the best predictor of the quantity of organisms that would be impinged or entrained within
a given aquatic system (Henderson and Seaby 2000). Because cooling towers minimize the
volume of water withdrawn by a nuclear power plant, the impacts of IM&E from a plant with
cooling towers that operates in a fully closed-cycle mode would generally be smaller than the
impacts from a plant with a once-through cooling system or a cooling pond. This finding is
further supported by the EPA’s 2014 CWA Section 316(b) regulations for existing facilities at
40 CFR 122 and 40 CFR 125, Subpart J (79 FR 48300). As described in Section 4.6.1.2 under
“Clean Water Act Section 316(b) Requirements for Minimizing IM&E at Existing Facilities,”
operation of a closed-cycle recirculating system is an essentially preapproved technology for
achieving impingement mortality BTA. This finding does not apply to nuclear power plants that
seasonally or intermittently use cooling towers in a helper mode to mitigate thermal effects,
entrainment, or consumptive water use, but that otherwise operate as once-through systems.
These hybrid systems are included under the evaluation of once-through cooling water intake
systems above.
The 1996 and 2013 LR GEISs determined that impingement may result in sublethal effects that
could increase the susceptibility of fish or shellfish to predation, disease, or parasitism.
However, only once-through cooling systems were anticipated to be of concern for this issue.
The lower volume of water required by nuclear power plants with cooling towers that operate in
a fully closed-cycle mode would also minimize this potential effect. The 1996 and 2013
LR GEISs reported that neither scientific literature reviews nor consultations with agencies or
utilities yielded clear evidence of sublethal effects on fish or finfish resulting in noticeable
increases in impinged organisms’ susceptibility to predation, parasitism, or disease, regardless
of cooling system type. Since the publication of the 2013 LR GEIS, the NRC has identified no
information about this issue for plants with cooling towers. The available information indicates
that these secondary impacts of impingement are not expected to be of concern during initial LR
or SLR terms at nuclear power plants with cooling towers. As stated earlier in this section,
because entrainable organisms generally consist of fragile life stages, all entrained organisms
are assumed to die (79 FR 48300). Therefore, sublethal effects of entrainment do not apply.
In considering the effects of IM&E of closed-cycle cooling systems on aquatic ecology, the NRC
evaluated the same issues that were evaluated for nuclear power plants with once-through
cooling systems or cooling ponds in Section 4.6.1.2.1. No significant impacts on aquatic
populations have been reported at any existing nuclear power plants with cooling towers
operating in a closed-cycle mode in scientific literature or in license renewal SEISs published to
date. Initial LR or SLR would continue current operating conditions and environmental stressors
rather than introduce wholly new impacts. Therefore, the impacts of current operations and
license renewal on aquatic resources would be similar. For these reasons, the effects of IM&E
on aquatic organisms at plants with cooling towers would be minor and would neither destabilize
nor noticeably alter any important attribute of finfish or shellfish populations in source
waterbodies during initial LR or SLR terms. As part of obtaining BTA determinations under
CWA 316(b), permitting authorities may require some nuclear power plants to implement
additional plant-specific controls to reduce IM&E. Implementation of such controls would further
reduce or mitigate IM&E during the license renewal term. The staff reviewed information in
scientific literature and from SEISs (for initial LRs and SLRs) completed since development of
the 2013 LR GEIS and identified no new information or situations that would result in different
impacts for this issue for either an initial LR or SLR term. The NRC concludes that the impacts

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of IM&E on aquatic organisms during the license renewal term (initial LR or SLR) would be
SMALL for nuclear power plants with cooling towers operated in a fully closed-cycle mode. This
is a Category 1 issue.
4.6.1.2.3

Entrainment of Phytoplankton and Zooplankton

This issue pertains to the entrainment of phytoplankton and zooplankton during an initial LR or
SLR term. The IM&E of fish and shellfish, including ichthyoplankton and larval stages of
shellfish, are addressed above in two issues based on cooling water intake system type in
Sections 4.6.1.2.1 and 4.6.1.2.2.
In the 1996 and 2013 LR GEISs, the NRC determined that entrainment of phytoplankton and
zooplankton would be SMALL at all nuclear power plants. Therefore, this was considered a
Category 1 issue for all plants regardless of cooling water intake system type. Impingement
does not apply to phytoplankton or zooplankton because these organisms are too small to be
trapped against intake structure screening devices.
Most nuclear power plants were required to monitor for entrainment effects during the initial
years of operation. The effects of entrainment on phytoplankton and zooplankton are
considered to be of SMALL significance if monitoring indicates no evidence that nuclear power
plant operation has reduced or otherwise affected populations of these organisms in the source
waterbody. For example, about 70 percent of the copepods (a group of planktonic crustaceans)
entrained at the Millstone plant in Connecticut suffered mortality, but this loss only represented
0.1 to 0.3 percent of the copepod production of eastern Long Island Sound (Carpenter et al.
1974). At the Calvert Cliffs plant, which withdraws cooling water from the Chesapeake Bay in
Maryland, entrainment survival for the five most abundant zooplankton species was 65 to
100 percent (NRC 1999c). At the D.C. Cook plant on Lake Michigan, researchers determined
that zooplankton losses associated with entrainment were too small to be detected in the lake.
Researchers concluded that fish predation, rather than entrainment, was the major source of
zooplankton mortality in inshore waters during most of the year (Evans et al. 1986). At the
Seabrook plant on the Gulf of Maine in New Hampshire, researchers compared the densities of
holoplankton, meroplankton, and hyperbenthos taxa prior to and during operation at nearfield
and farfield sites and found no significant differences in densities prior to and during operations
or between the sampling sites (NAI 1998). Researchers also found no significant differences in
phytoplankton abundance or chlorophyll concentrations between the nearfield and farfield sites,
nor was there any significant difference prior to and during operations (NAI 1998). Based on
these results, the NRC (NRC 2015b) found that Seabrook operation had not noticeably altered
zooplankton or phytoplankton abundance near the Seabrook site.
Initial LR or SLR would continue current operating conditions and environmental stressors
rather than introduce wholly new impacts. Therefore, the impacts of current operations and
license renewal on aquatic resources would be similar. For these reasons, the effects of
entrainment of phytoplankton and zooplankton would be minor and would neither destabilize nor
noticeably alter any important attribute of populations of these organisms in source waterbodies
during the initial LR or SLR terms of any nuclear power plants. As part of obtaining BTA
entrainment determinations under CWA 316(b), permitting authorities may require some nuclear
power plants to implement additional plant-specific controls to reduce entrainment.
Implementation of such controls would further reduce or mitigate entrainment of phytoplankton
and zooplankton. The staff reviewed information in scientific literature and from SEISs (for
initial LRs and SLRs) completed since development of the 2013 LR GEIS and identified no new
information or situations that would result in different impacts for this issue for either an initial LR

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or SLR term. The NRC concludes that the impacts of entrainment of phytoplankton and
zooplankton during the license renewal term (initial LR or SLR) would be SMALL for all nuclear
power plants. This is a Category 1 issue.
4.6.1.2.4

Effects of Thermal Effluents on Aquatic Organisms (Plants with Once-Through
Cooling Systems or Cooling Ponds)

This issue pertains to acute, sublethal, and community-level effects of thermal effluents on
finfish and shellfish from operation of nuclear power plants with once-through cooling systems
and cooling ponds during an initial LR or SLR term. This includes plants with helper cooling
towers that are seasonally operated to reduce thermal load to the receiving waterbody, reduce
entrainment in the during peak spawning periods, or reduce consumptive water use during
periods of low river flow. The effects of thermal effluents on aquatic organisms at nuclear power
plants with cooling towers operated in a fully closed-cycle mode are addressed in
Section 4.6.1.2.5. Infrequently reported effects of thermal effluents are addressed in
Section 4.6.1.2.6.
In the 1996 and 2013 LR GEISs, the NRC determined that the effects of thermal effluents on
aquatic organisms would be SMALL at many nuclear power plants with once-through cooling
systems or cooling ponds, as well as plants that operate in a hybrid mode (i.e., once-through
cooling with cooling towers that operate intermittently), but that these impacts could be
MODERATE or LARGE at some plants. Therefore, this was considered a Category 2 issue for
these plants. In the 1996 LR GEIS, this issue was evaluated as “heat shock.” The 2013
LR GEIS retitled this issue to “thermal impacts on aquatic organisms (plants with once-through
cooling systems or cooling ponds)” to acknowledge that, in addition to acute effects, aquatic
organisms could suffer sublethal effects from exposure to thermal effluents. For instance, during
some license renewal environmental reviews, thermal effluents have been found to seasonally
affect the geographic distribution or diversity of aquatic organisms (see Table 4.6-5 and the
discussion concerning Peach Bottom plant’s thermal effluent in Section 4.6.1.2 under, “Thermal
Impacts”). This LR GEIS refines the title of this issue from “Thermal impacts on aquatic
organisms (plants with once-through cooling systems or cooling ponds)” to “Effects of thermal
effluents on aquatic organisms (plants with once-through cooling systems or cooling ponds)” for
clarity and consistency with other ecological resource LR GEIS issue titles.
When available, the NRC staff relies on the expertise and authority of the NPDES permitting
authority with respect to thermal impacts on aquatic organisms. Therefore, if the NPDES
permitting authority has made a determination under CWA Section 316(a) that thermal effluent
limits are sufficiently stringent to assure the protection and propagation of a balanced,
indigenous population of shellfish, fish, and wildlife in and on the receiving body of water, and
the nuclear power plant has implemented any associated requirements, then the NRC staff
assumes that adverse impacts on the aquatic environment will be minimized (see
10 CFR 51.10(c); 10 CFR 51.53(c)(3)(ii)(B); and 10 CFR 51.71(d) [10 CFR Part 51]). In such
cases, the NRC staff concludes that thermal impacts on aquatic organisms would be SMALL
over the course of the initial LR or SLR term for these nuclear power plants.
In cases where the NPDES permitting authority has not granted a CWA Section 316(a)
variance, the NRC staff analyzes the potential impacts of thermal discharges using a
weight-of-evidence approach. In this approach, the staff considers multiple lines of evidence to
assess the presence or absence of ecological impairment (i.e., noticeable or detectable impact)
on the aquatic environment. For instance, as its lines of evidence, the staff might consider the
characteristics of the cooling water discharge system design, the results of thermal studies

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performed at the facility, and the trends in fish and shellfish population abundance indices. The
staff then considers these lines of evidence together to predict the level of impact (SMALL,
MODERATE, or LARGE) that the aquatic environment is likely to experience over the course of
the initial LR or SLR term.
The staff reviewed information from SEISs (for initial LRs and SLRs) completed since
development of the 2013 LR GEIS. In summary, the potential effects of thermal effluent
discharges during an initial LR or SLR term depends on numerous site-specific factors,
including the ecological setting of the nuclear power plant; the characteristics of the cooling
system and effluent discharges; and the characteristics of the fish, shellfish, and other aquatic
organisms present in the area (e.g., life history, distribution, population trends, management
objectives, etc.). Additionally, whether the NPDES permitting authority has granted a 316(a)
variance is also a relevant factor. In general, if the NPDES permitting authority has granted such
a variance and the nuclear power plant has implemented any associated requirements, then the
NRC staff assumes that adverse impacts on the aquatic environment will be minimized and that
thermal impacts will be SMALL; if this is not the case, impacts could be SMALL, MODERATE,
or LARGE.
The NRC concludes that the effects of thermal effluents on aquatic organisms during the license
renewal term (initial LR or SLR) at nuclear power plants with once-through cooling or cooling
ponds could be SMALL, MODERATE, or LARGE. This is a Category 2 issue.
4.6.1.2.5

Effects of Thermal Effluents on Aquatic Organisms (Plants with Cooling Towers)

This issue pertains to acute, sublethal, and community-level effects of thermal effluents on
finfish and shellfish from operation of nuclear power plants with cooling towers operated in a
fully closed-cycle mode during an initial LR or SLR term. The effects of thermal effluents on
aquatic organisms at nuclear power plants with once-through cooling systems or cooling ponds
are addressed in Section 4.6.1.2.4. Infrequently reported effects of thermal effluents are
addressed in Section 4.6.1.2.6.
In the 1996 and 2013 LR GEISs, the NRC determined that the effect of thermal effluents on
aquatic organisms would be SMALL at all nuclear power plants with cooling towers operated in
a fully closed-cycle mode. Therefore, this was considered a Category 1 issue for these plants. In
the 1996 LR GEIS, this issue was evaluated as “heat shock.” The 2013 LR GEIS retitled this
issue to “Thermal impacts on aquatic organisms (plants with cooling towers)” to acknowledge
that, in addition to acute effects, aquatic organisms could suffer sublethal effects from exposure
to thermal effluents. This LR GEIS refines the title of this issue from “Thermal impacts on
aquatic organisms (plants with cooling towers)” to “Effects of thermal effluents on aquatic
organisms (plants with cooling towers)” for clarity and consistency with other ecological
resource LR GEIS issue titles.
In the 1996 and 2013 LR GEISs, the NRC found that the effects of thermal effluents on aquatic
organisms at plants with cooling towers operated in a fully closed-cycle mode did not result in
noticeable effects on aquatic populations within receiving waterbodies, and this impact was not
expected to be an issue during the license renewal term. This finding was based, in part, on the
presence of smaller thermal plumes at plants with closed-cycle cooling systems.
When considering the effects of thermal effluents of closed-cycle cooling systems on aquatic
organisms, the NRC evaluated the same issues that were evaluated for plants with
once through cooling systems or cooling ponds in Section 4.6.1.2.4. No significant impacts on

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aquatic populations have been reported at any existing nuclear power plants with cooling towers
operating in a closed-cycle mode in scientific literature or in license renewal SEISs published to
date. Initial LR or SLR would continue current operating conditions and environmental stressors
rather than introduce wholly new impacts. Therefore, the impacts of current operations during
initial LR or SLR on aquatic resources would be similar. For these reasons, the effects of
thermal effluents on aquatic organisms at plants with cooling towers would be minor and would
neither destabilize nor noticeably alter any important attribute of aquatic populations in receiving
waterbodies during initial LR or SLR terms. As part of obtaining a variance under CWA
Section 316(a), permitting authorities may impose conditions concerning thermal effluent
discharges at some nuclear power plants. Implementation of such conditions would further
reduce or mitigate thermal impacts during the license renewal term. The staff reviewed
information in scientific literature and from SEISs (for initial LRs and SLRs) completed since
development of the 2013 LR GEIS and identified no new information or situations that would
result in different impacts for this issue for either an initial LR or SLR term.
The NRC concludes that the effects of thermal effluents on aquatic organisms during the license
renewal term (initial LR or SLR) would be SMALL for nuclear power plants with cooling towers
operated in a fully closed-cycle mode. This is a Category 1 issue.
4.6.1.2.6

Infrequently Reported Effects of Thermal Effluents

This issue concerns the infrequently reported effects of thermal effluents during an initial LR or
SLR term. These effects include cold shock, thermal migration barriers, accelerated maturation
of aquatic insects, and proliferated growth of aquatic nuisance species, as well as the effects of
thermal effluents on dissolved oxygen, gas supersaturation, and eutrophication. This issue also
considers sublethal stresses associated with thermal effluents that can increase the
susceptibility of exposed organisms to predation, parasitism, or disease.
In the 1996 and 2013 LR GEISs, the NRC determined that the infrequently reported effects of
thermal effluents would be SMALL at all nuclear power plants. Therefore, this was considered a
Category 1 issue. The 1996 LR GEIS evaluated this issue as eight separate issues; the
2013 LR GEIS consolidated these issues into two issues titled “Infrequently reported thermal
impacts (all plants)” and “Effects of cooling water discharge on dissolved oxygen, gas
supersaturation, and eutrophication.” This LR GEIS further consolidates these two issues, as
well as the thermal effluent component of the issue of “Losses from predation, parasitism, and
disease among organisms exposed to sublethal stresses,”13 (a Category 1 issue in both the
1996 and 2013 LR GEISs) into one issue. This LR GEIS refines the title of this issue to
“Infrequently reported effects of thermal effluents” for clarity and consistency with other
ecological resource LR GEIS issue titles.

13

The potential for impingement to cause sublethal stresses that increase the susceptibility of aquatic
organisms to predation, parasitism, or disease is evaluated in Section 4.6.1.2.1 (plants with once-through
cooling systems or cooling ponds) and Section 4.6.1.2.2 (plants with cooling towers). Entrainment would
not result in sublethal stresses because entrainable organisms generally consist of fragile life stages, and
all entrained organisms are assumed to die (79 FR 48300).

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Cold Shock
Cold shock occurs when an organism has been acclimated to a specific water temperature or
range of temperatures and is subsequently exposed to a rapid decrease in temperature. This
can result in a cascade of physiological and behavioral responses and, in some cases, death
(Donaldson et al. 2008). Rapid temperature decreases may occur from either natural sources
(e.g., thermocline temperature variation and storm events) or anthropogenic sources (e.g.,
thermal effluent discharges). The magnitude, duration, and frequency of the temperature
change, as well as the initial acclimation temperatures of individuals, can influence the extent of
the consequences of cold shock on fish and other aquatic organisms (Donaldson et al. 2008). At
nuclear power plants, cold shock could occur during refueling outages, reductions in power
generation level, or other situations that would quickly reduce the amount of cooling capacity
required at the plant. Cold shock is most likely to be observable in the winter. The 1996
LR GEIS reports that cold shock events have only rarely occurred at nuclear power plants
(e.g., Haddam Neck [no longer operating] in Connecticut, Prairie Island and Monticello in
Minnesota, and Oyster Creek [no longer operating] in New Jersey). Fish mortalities usually
involved only a few fish and did not result in population-level effects. Gradual depowering or
shutdown of plant operations, especially in winter months, can mitigate the effects of cold shock.
No cold shock events have been reported since the events described in the 1996 LR GEIS
occurred, and no noticeable or detectable impacts on aquatic populations have been reported at
any existing nuclear power plants related to this issue in scientific literature or in license renewal
SEISs published to date. The available information indicates that cold shock resulting from
thermal effluents of nuclear power plants is not of concern for initial LR or SLR.
Thermal Migration Barriers
Thermal effluents have the potential to create migration barriers if the thermal plume covers an
extensive cross-sectional area of a river and temperatures within the plume exceed a species’
physiological tolerance limit. This impact has been examined at several nuclear power plants,
but it has not been determined to result in observable effects. For example, at Vermont Yankee
Nuclear Power Station (Vermont Yankee) (no longer operating) on the Connecticut River in
Vermont, the NRC examined the potential for the plant’s thermal plume to affect the
outmigration of American shad and Atlantic salmon (Salmo salar). This potential effect was of
particular concern because the fish passage facility was located on the same side of the river as
the plant’s discharge, and a hydroelectric facility was located immediately downstream
(NRC 2007d). However, the licensee’s CWA Section 316(b) demonstration found that smolt
migration of these species would not be affected because the thermal plume covered only a
small cross-sectional area of the river. The NRC staff also examined this potential effect
related to migration of federally endangered sturgeon (Acipenser brevirostrum and
A. oxyrinchus oxyrinchus) past the Surry plant on the James River in Virginia (NRC 2020m) and
past the Indian Point plant (no longer operating) on the Hudson River in New York (NRC
2018e). To date, thermal effluents of nuclear power plants have resulted in no noticeable or
detectable impacts on the migrations of fish. The available information indicates that migration
barriers resulting from thermal effluents of nuclear power plants are not of concern for initial LR
or SLR.
Accelerated Maturation of Aquatic Insects
The 1996 and 2013 LR GEISs determined that the heated effluents of nuclear power plants
could accelerate the maturation of aquatic insects in freshwater systems and cause premature
emergence. The maturation and emergence of aquatic insects are often closely associated with

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water temperature regimes. If insects develop or emerge early in the season, they may be
unable to feed or reproduce or they may die because the local climate is not warm enough to
support them. Premature emergence has been observed in laboratory investigations
(e.g., Nebeker 1971) but not in field investigations (e.g., Langford 1975). To date, thermal
effluents of nuclear power plants have resulted in no noticeable or detectable impacts on the life
cycles of aquatic insects. The available information indicates that accelerated maturation of
aquatic insects resulting from thermal effluents of nuclear power plants is not of concern for
initial LR or SLR.
Proliferation of Aquatic Nuisance Organisms
The 1996 and 2013 LR GEISs also considered that heated effluents could proliferate the growth
of aquatic nuisance organisms. Aquatic nuisance species are organisms that disrupt the
ecological stability of infested inland (e.g., rivers and lakes), estuarine, or marine waters
(EPA 2023e). The previous LR GEISs discuss zebra mussels (Dreissena polymorpha) and
Asiatic clam (Corbicula fluminea), two bivalves that are of particular concern in many freshwater
systems because they can cause significant biofouling of industrial intake pipes at power and
water facilities. These species are also of ecological concern because they outcompete and
lead to the decline of native freshwater mussels. Nuclear power plants that withdraw water from
waterbodies in which these species are known to occur often periodically chlorinate intake pipes
or have other procedures in place to mitigate the spread of these bivalves. There is no
evidence, however, that thermal effluent leads to these species’ proliferation. No noticeable or
detectable impacts on aquatic populations have been reported at any existing nuclear power
plants related to this issue in scientific literature or in license renewal SEISs published to date.
Langford (1983) reports several instances in which wood-boring crustaceans and mollusks,
notably “shipworms,” have caused concern in British waters. Although increased abundance of
shipworms in the area influenced by heated power plant effluents caused substantial damage to
wooden structures, replacement of old wood with concrete or metal structures eliminated the
problem. Langford concluded that increased temperatures could enhance the activity and
reproduction of wood-boring organisms in enclosed or limited areas but that elevated
temperature patterns were not sufficiently stable to cause widespread effects. The influence of
the operation of the Oyster Creek plant (no longer operating) on Barnegat Bay on the
abundance and distribution of the shipworm Teredo bartschi has been extensively studied (see
summary by Kennish and Lutz 1984). Although studies have varied somewhat in their
conclusions, researchers have agreed that heated effluents from the Oyster Creek plant
increased the distribution and abundance of these organisms (Kennish and Lutz 1984). This
species has not been found in Barnegat Bay since 1982, perhaps because of reduced water
temperatures during a station outage in the winter of 1981-82 and the pathological effects of a
parasite, as well as the removal of substantial amounts of driftwood and the replacement of
untreated structural wood in the area of concern (NRC 1996). The NRC has identified no other
concerns about nuisance aquatic organisms associated with nuclear power plant thermal
effluents in scientific literature or in license renewal SEISs published to date. The available
information indicates that proliferation of nuisance organisms resulting from thermal effluents of
nuclear power plants is not of concern for initial LR or SLR.
Dissolved Oxygen
Aerobic organisms, such as fish, require oxygen, and the concentration of dissolved oxygen in a
waterbody is one of the most important ecological water quality parameters. Dissolved oxygen
also influences several inorganic chemical reactions. In general, dissolved oxygen

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concentrations of less than 3 ppm in warmwater habitats or less than 5 ppm in cold-water
habitats can adversely affect fish (Morrow and Fischenich 2000). Oxygen dissolves into water
via diffusion, aeration, and as a product of photosynthesis. The amount of oxygen water can
absorb depends on temperature; the amount of oxygen that can dissolve in a volume of water
(i.e., the saturation point) is inversely proportional to the temperature of the water. Thus, when
other chemical and physical conditions are equal, the warmer the water is, the less dissolved
oxygen it can hold. Increased water temperatures also affect the amount of oxygen that aquatic
organisms need by increasing metabolic rates and chemical reaction rates. The rates of many
chemical reactions in water approximately doubles for every 18°F (10°C) increase in
temperature.
The thermal effluent discharges of nuclear power plants have the potential to stress aquatic
organisms by simultaneously increasing these organisms’ need for oxygen and decreasing
oxygen availability. Aquatic organisms are more likely to experience adverse effects from
thermal effluents in ecosystems where dissolved oxygen levels are already approaching
suboptimal levels as a result of other factors in the environment. This is most likely to occur in
ecosystems where increased levels of detritus and nutrients (e.g., eutrophication), low flow, and
high ambient temperatures already exist. These conditions can occur as a result of drought
conditions or in hot weather, especially in lakes, reservoirs, or other dammed freshwaters.
Although the thermal effluents of nuclear power plants may contribute to reduced dissolved
oxygen in the immediate vicinity of the discharge point, as the effluent disperses, diffusion and
aeration from turbulent movement introduces additional oxygen into the water. As the water
cools, the saturation point increases, and the water can absorb additional oxygen as it is
released by aquatic plants and algae through photosynthesis, which is a continuously ongoing
process during daylight hours. Therefore, lower dissolved oxygen is generally only a concern
within the thermal mixing zone, which is typically a small area of the receiving waterbody. As
described earlier in Section 4.6.1.2 under “Clean Water Act Section 316(a) Requirements for
Point Source Discharges,” many states address thermal mixing zones in State water quality
criteria to ensure that mixing zones provide a continuous zone of passage for aquatic
organisms. Additionally, the EPA, or authorized States and Tribes, often impose conditions
specifically addressing dissolved oxygen through NPDES permits to ensure that receiving
waterbodies maintain adequate levels of oxygen to support aquatic life. These conditions are
established pursuant to CWA Section 316(a), which requires that regulated facilities operate
under effluents limitations that assure the protection and propagation of a balanced, indigenous
population of shellfish, fish, and wildlife in and on the receiving waterbody. No noticeable or
detectable impacts on aquatic populations have been reported at any existing nuclear power
plants related to oxygen availability in scientific literature or in license renewal SEISs published
to date. The available information indicates that reduced dissolved oxygen resulting from
thermal effluents of nuclear power plants is not of concern for initial LR or SLR.
Gas Supersaturation
Rapid heating of cooling water can also affect the solubility and saturation point of other
dissolved gases, including nitrogen. As water passes through the condenser cooling system, it
can become supersaturated with gases. Once the supersaturated water is discharged in the
receiving waterbody, dissolved gas levels equilibrate as the effluent cools and mixes with
ambient water. This process is of concern if aquatic organisms remain in the supersaturated
effluent for a long enough period to become equilibrated to the increased pressure associated
with the effluent. If these organisms then move into water of lower pressure too quickly when,
for example, swimming out of the thermal effluent or diving to depths, the dissolved gases within

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the affected tissues may come out of solution and form embolisms (bubbles). The resulting
condition is known as gas bubble disease. In fish, it is most noticeable in the eyes and fins.
Affected tissues can swell or hemorrhage and result in behavioral abnormalities, increased
susceptibility to predation, or death (Noga 2000). Mortality in fish generally occurs at gas
supersaturation levels above 110 or 115 percent (EPA 1986). Aquatic insects and crustaceans
appear to be more tolerant of supersaturated water (Nebeker et al. 1981).
The ability to detect and avoid supersaturated waters varies among species. A fish can avoid
supersaturated waters by either not entering the affected area or by diving to avoid the onset of
supersaturated conditions near the surface. Some species, however, may not avoid
supersaturated waters until symptoms of gas bubble disease occur; at that point, some fish may
already be lethally exposed. Other species may be attracted to supersaturated waters because
it is often warmer (Gray et al. 1983).
As reported in the 1996 and 2013 LR GEISs, fish mortality from gas bubble disease has been
reported at hydroelectric dams and coal-fired power plants. Typically, gas bubble disease is of
concern at facilities where the configuration of the discharge allows organisms to reside in the
supersaturated effluent for extended periods of time (e.g., discharge canals that fish can freely
enter). Fish mortality from gas bubble disease has been observed at one nuclear power plant:
the Pilgrim plant (no longer operating) on Cape Cod in Massachusetts. In 1973 and 1976,
43,000 and 5,000 Atlantic menhaden deaths, respectively, were attributed to gas bubble
disease because of individuals entering and residing in the discharge canal for a prolonged
period (McInerny 1990). Some sources reported that other species of fish may also have been
affected (Fairbanks and Lawton 1977). After these events, the Pilgrim plant installed a barrier
net to prevent fish from entering the discharge canal, and no such events occurred again
following implementation of this mitigation. Discharges that promote the rapid mixing of effluent
into receiving waters, such as those equipped with multiport or jet diffusers, can also be
effective in preventing gas bubble disease mortalities because they limit the extent of the
thermal plume and promote rapid mixing (Lee and Martin 1975).
No noticeable or detectable impacts on aquatic populations have been reported at any other
nuclear power plants related to gas supersaturation in scientific literature or in license renewal
SEISs published to date. The one plant for which this was of concern (Pilgrim) successfully
mitigated the issue in the 1970s and did not report any other such events for the remainder of its
operating period (i.e., through 2019, when the plant permanently shut down). Additionally,
NPDES permit conditions established pursuant to CWA Section 316(a) may also address
thermal effluent factors that would reduce the potential for aquatic organisms to experience gas
bubble disease as a result of nuclear power plant thermal effluents. The available information
indicates that gas supersaturation resulting from thermal effluents of nuclear power plants is not
of concern for initial LR or SLR.
Eutrophication
An early concern about nuclear power plant discharges was that thermal effluents would cause
or speed eutrophication by stimulating biological productivity in receiving waterbodies
(NRC 1996). Eutrophication is the gradual increase in the concentration of phosphorus,
nitrogen, and other nutrients in a slow-flowing or stagnant aquatic ecosystem, such as a lake.
These nutrients enter the ecosystem primarily through runoff from agricultural land and
impervious surfaces. The increase in nutrient content allows alga to proliferate on the water’s
surface, which reduces light penetration and oxygen absorption necessary for underwater life.
The 1996 LR GEIS reports that several nuclear power plants conducted long-term monitoring to

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investigate this potential effect, including the McGuire plant on Lake Norman in North Carolina
and Oconee plant on Lake Keowee in South Carolina. No evidence of eutrophication was
detected. No such effects have been reported in scientific literature or in license renewal SEISs
to date. Therefore, eutrophication is not expected to be of concern during initial LR or
SLR terms at any nuclear power plants.
Susceptibility to Predation, Parasitism, and Disease
Fish and shellfish that are exposed to the thermal effluent of a nuclear power plant may
experience stunning, disorientation, or injury. These sublethal effects can subsequently affect
an organism’s susceptibility to predation, parasitism, or disease.
With respect to susceptibility to predation, laboratory studies of the secondary mortality of fish
following exposure to heat or cold shock demonstrate increased susceptibility of these fish to
predation; however, field evidence of such effects is often limited to anecdotal information, such
as observations of increased feeding activity of seagulls and predatory fish near effluent outfalls
(e.g., Cada et al. 1981). For example, Barkley and Perrin (1971) and Romberg et al. (1974)
reported increased concentrations of predators feeding on forage fish attracted to thermal
plumes. However, these studies did not quantify whether the observed behaviors resulted in
population-level effects on prey species.
With respect to susceptibility to parasitism and disease, Langford (1983) found that the
tendency for fish to congregate in heated effluent plumes, the increased physiological stress
that higher water temperatures exert on fish, and the ability of some diseases and parasites to
proliferate at higher temperatures were all factors that could contribute to increased rates of
disease or parasitism in exposed fish. Some studies have suggested that crowding of fish within
the thermal plume, rather than the thermal plume itself, may lead to an increased risk of
exposure to infectious diseases (Coutant 1987).
The 1996 and 2013 LR GEISs reported that neither scientific literature reviews nor consultations
with agencies or utilities yielded clear evidence of sublethal effects on fish or finfish resulting in
noticeable increases in exposed organisms’ susceptibility to predation, parasitism, or disease.
Since the publication of the 2013 LR GEIS, the NRC has determined that thermal effects on
aquatic organisms at four nuclear power plants could be SMALL to MODERATE during the
license renewal term (see Table 4.6-5). At three of the four plants (i.e., Braidwood, LaSalle,
and Turkey Point), these impacts were limited to species confined to cooling pond
environments. In the fourth example (Peach Bottom), the adverse effects were found to be
confined to a narrow band of shallow water habitat downstream of the discharge canal during
the summer months. However, increased susceptibility to predation, parasitism, or disease or
predation resulting from exposure to thermal effluent was not found to be responsible for these
small to moderate findings. Rather, these effects were attributed to other acute (i.e., heat shock)
or community-level effects (i.e., reduced habitat availability or quality and reduced species
diversity over time) of thermal effluents evaluated as part of the former Category 2 issue,
“Thermal impacts on aquatic organisms (plants with once-through cooling systems or cooling
ponds).” This Category 2 issue has been renamed in this LR GEIS (see Section 4.6.1.2.4). The
available information indicates that this issue is not expected to be of concern during initial LR
or SLR terms at any nuclear power plants.

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Conclusion
Initial LR or SLR would continue current operating conditions and environmental stressors
rather than introduce wholly new impacts. Therefore, the impacts of current operations and
license renewal on aquatic resources would be similar. For these reasons, the infrequently
reported effects of thermal effluents discussed in this section would be minor and would neither
destabilize nor noticeably alter any important attribute of aquatic populations in receiving
waterbodies during initial LR or SLR terms of any nuclear power plants. As part of obtaining a
variance under CWA Section 316(a), permitting authorities may impose conditions concerning
thermal effluent discharges at some nuclear power plants. Implementation of such conditions
would further reduce or mitigate thermal impacts during the license renewal term. The staff
reviewed information in scientific literature and from SEISs (for initial LRs and SLRs) completed
since development of the 2013 LR GEIS and identified no new information or situations that
would result in different impacts for this issue for either an initial LR or SLR term. The NRC
concludes that infrequently reported effects of thermal effluents during the license renewal term
(initial LR or SLR) would be SMALL for all nuclear power plants. This is a Category 1 issue.
4.6.1.2.7

Effects of Nonradiological Contaminants on Aquatic Organisms

This issue concerns the potential effects of nonradiological contaminants on aquatic organisms
that could occur as a result of nuclear power plant operations during an initial LR or SLR term.
In the 1996 and 2013 LR GEISs, the NRC determined that the effects of nonradiological
contaminants on aquatic resources would be SMALL. Therefore, this was considered a
Category 1 issue.
This issue was originally of concern because some nuclear power plants used heavy metals in
condenser tubing that could leach from the tubing and expose aquatic organisms to these
contaminants. Because aquatic organisms can bioaccumulate heavy metals, even when
exposed at low levels, this can cause toxicity in fish and other animals that consume
contaminated organisms. Section 4.6.1.1.3 describes instances in which copper contamination
was an issue at operating nuclear power plants. Heavy metals have not been found to be of
concern other than these few instances, and in all cases, the nuclear power plants eliminated
leaching by replacing the affected piping.
In addition to heavy metals, nuclear power plants often add biocides to cooling water to kill
algae, bacteria, macroinvertebrates, and other organisms that could cause buildup in plant
systems and structures. For example, zebra mussels and Asiatic clams within the intake pipes
or cooling systems can cause partial to full blockage of grates and pipes or otherwise damage
the integrity of pipes and other cooling system components. Nuclear power plants in areas
where these mollusks are an operating concern typically treat cooling water with nonoxidizing
molluscicides that may include chlorine, chlorine dioxide, chloramines, ozone, bromine,
hydrogen peroxide and potassium permanganate. Most molluscicides have very restricted uses
due to their toxic effects on non-target organisms and are primarily used in closed systems.
Nuclear power plants typically maintain site procedures that specify when and how to treat the
cooling water system with such chemicals and BMPs to minimize impacts on the ecological
environment. For instance, plants use only EPA-approved biocides according to label
instructions. Some plants with cooling towers discharge blowdown to settling ponds to allow
heat and chemicals to dissipate before discharging the effluent to surface waters. NPDES
permits mitigate potential effects of chemical effluents by limiting the allowable concentrations in
effluent discharges to ensure the protection of the aquatic community within the receiving

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waterbody. Some nuclear power plants also use physical deterrents to reduce the need for
chemical treatment. For instance, the Browns Ferry plant in Alabama recirculates small sponge
balls through the condenser tubes to keep them clear of Asiatic clams (NRC 2005b).
Initial LR or SLR would continue current operating conditions and environmental stressors
rather than introduce wholly new impacts. Therefore, the impacts of current operations and
license renewal on aquatic resources would be similar. For these reasons, the effects of
nonradiological contaminants on aquatic organisms would be minor and would neither
destabilize nor noticeably alter any important attribute of populations of these organisms in
source waterbodies during initial LR or SLR terms of any nuclear power plants. Continued
adherence of nuclear power plants to chemical effluent limitations established in NPDES
permits would minimize the potential impacts of nonradiological contaminants on the aquatic
environment. The staff reviewed information in scientific literature and from SEISs (for initial LRs
and SLRs) completed since development of the 2013 LR GEIS and identified no new
information or situations that would result in different impacts for this issue for either an initial LR
or SLR term. The NRC concludes that the effects of nonradiological contaminants on aquatic
organisms during the license renewal term (initial LR or SLR) would be SMALL for all nuclear
power plants. This is a Category 1 issue.
4.6.1.2.8

Exposure of Aquatic Organisms to Radionuclides

This issue concerns the potential impacts on aquatic organisms from exposure to radionuclides
from routine radiological effluent releases during an initial LR or SLR term.
As explained in Section 4.6.1.1.2, radionuclides may be released from nuclear power plants into
the environment through several pathways, including via gaseous and liquid emissions. Aquatic
plants can absorb radionuclides that enter shallow groundwater or surface waters through their
roots. Aquatic animals can be exposed externally to ionizing radiation from radionuclides in
water, sediment, and other biota and can be exposed internally through ingested food, water,
and sediment and absorption through the integument and respiratory organs.
As discussed in Section 4.6.1.1.2, the DOE has produced a standard on a graded approach for
evaluating radiation doses to aquatic and terrestrial biota (DOE 2019). The DOE standard
provides methods, models, and guidance that can be used to characterize radiation doses to
terrestrial and aquatic biota exposed to radioactive material (DOE 2019). For aquatic animals,
the DOE guidance dose rate is 1 rad/d (0.1 Gy/d), which represents the level below which no
adverse effects to resident populations are expected. The DOE also recommends that the
screening-level concentrations of most radionuclides in aquatic environments should be based
on internal exposure as well as external exposure to contaminated sediments, rather than
external exposure to contaminated water (DOE 2019).
Previously, in the early 1990s, the International Atomic Energy Agency (1992) and the National
Council on Radiation Protection and Measurements (1991) also concluded that a chronic dose
rate of no greater than 1 rad/d (0.01 Gy/d) to the maximally exposed individual in a population of
aquatic organisms would ensure protection of the population. The United Nations Scientific
Committee on the Effects of Atomic Radiation concluded in 1996 and re-affirmed in 2008 that
chronic dose rates less than 0.4 mGy/hr (1.0 rad/day or 0.01 Gy/d) to the most highly exposed
individuals would be unlikely to have significant effects on most aquatic communities
(UNSCEAR 2010).

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In the 2013 LR GEIS, the NRC estimated the total radiological dose that aquatic biota would be
expected to receive during normal nuclear power plant operations using plant-specific
radionuclide concentrations in water and sediments at 15 nuclear power plants using Argonne
National Laboratory’s RESRAD-BIOTA dose evaluation model. The NRC found that total
calculated dose rates for aquatic animals at all 15 plants were all less than 0.2 rad/d
(0.002 Gy/d), which is less than the guideline value of 1 rad/d (0.01 Gy/d). As a result, the NRC
anticipated in the 2013 LR GEIS that normal operations of these facilities would not result in
negative effects on aquatic biota. The 2013 LR GEIS concluded that the impact of radionuclides
on aquatic biota from past operations would be SMALL for all nuclear power plants and would
not be expected to change appreciably during the license renewal period.
In this revision, the NRC staff conducted an updated and expanded analysis of this issue
relative to the 2013 LR GEIS. As part of this expanded analysis, the staff reviewed a subset of
operating nuclear power plants14 to evaluate the potential impacts of radionuclides on biota from
continued operations. Section 4.6.1.1.2 describes the NRC staff’s methods, which included
reviewing effluent release reports, a RESRAD-BIOTA analysis, and an ICRP biota dose
calculator analysis (see Section G.6.2 in Appendix G for full description of methodology).
Results can be found in Section 4.6.1.1.2 and are summarized in this section.
Table 4.6-1 in Section 4.6.1.1.2 shows the estimated radiation dose rates to four ecological
receptors (i.e., riparian animal, terrestrial animal, terrestrial plant, and aquatic animal) resulting
from the staff’s RESRAD-BIOTA dose modeling. Based on the staff’s RESRAD-BIOTA analysis,
it is unlikely that radionuclide releases during normal operations of these nuclear power plants
would have adverse effects on resident populations of aquatic animals because the calculated
doses are well below DOE protective guidelines.
In addition to the RESRAD-BIOTA analysis discussed above, the NRC staff estimated dose
rates to a riparian organism using the ICRP biota dose calculator (ICRP 2022) (see
Section 4.6.1.1.2 and Section G.6.2 in Appendix G for full description of ICRP BiotaDC
methodology). The dose rates calculated for a riparian organism ranged between 2 × 10-4 and
2 × 10-5 rad/d which is orders of magnitude lower than the DOE guideline dose rate. None of the
radionuclides evaluated singly, or in common, produced dose rates that approached the DOE’s
guidance dose rate of 0.1 rad/d for riparian animals using the ICRP BiotaDC tool (DOE 2019).
Additionally, the calculated dose rates did not approach the level advocated by the National
Council on Radiation Protection and Measurements to initiate additional evaluation (Cool et al.
2019). In fact, the dose rates for the riparian organism calculated using the ICRP’s calculator
were lower than the RESRAD conservative analysis, and both were well below the DOE
guideline values.
Initial LR or SLR would continue current operating conditions and environmental stressors
rather than introduce wholly new impacts. Therefore, the impacts of current operations and
initial LR or SLR on aquatic organisms would be similar. For these reasons, the effects of
exposure of aquatic organisms to radionuclides would be minor and would neither destabilize
nor noticeably alter any important attribute of populations of exposed organisms during initial LR
or SLR terms of any nuclear power plant. Continued adherence of nuclear power plants to
regulatory limits on radioactive effluent releases would minimize the potential impacts on the
aquatic environment. Doses to aquatic organisms would be expected to remain below the
14

The subset of plants included the following PWR plants: Comanche Peak, D.C. Cook, Palo Verde 1-3,
Robinson, Salem 1-2, Seabrook, and Surry; and the following BWR plants: Fermi 2, Hatch 1-2, Hope
Creek, Limerick, and Columbia.

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DOE’s dose limits and, therefore, impacts to aquatic communities are not expected. The staff
reviewed information in scientific literature and from SEISs (for initial LRs or SLRs) completed
since development of the 2013 LR GEIS and identified no new information or situations that
would result in different impacts for this issue for either an initial LR or SLR term.
The NRC concludes that the impacts of exposure of aquatic organisms to radionuclides during
the license renewal term (initial LR or SLR) would be SMALL for all nuclear power plants. This is
a Category 1 issue.
4.6.1.2.9

Effects of Dredging on Aquatic Resources

This issue concerns the effects of dredging at nuclear power plants on aquatic resources during
an initial LR or SLR term.
In the 2013 LR GEIS, the NRC determined that the effects of dredging on aquatic resources
would be SMALL at all nuclear power plants. Therefore, this was considered a Category 1 issue
for all nuclear power plants. The 1996 LR GEIS did not address this issue.
Small-particle sediment, such as sand and silt, that enters waterbodies through erosion can
subsequently deposit and accumulate along shorelines and in shallow water areas. If sediment
deposition affects cooling system function or reliability, a nuclear power plant may need to
periodically dredge to improve intake flow and keep the area clear of sediment. Nuclear power
plants where dredging may be necessary are typically located along fast-flowing waters with
sandy or silty bottoms, such as large rivers or the ocean. In some instances, dredging may be
performed to maintain barge slips for transport of materials and waste to and from the site.
Dredging entails excavating a layer of sediment from the affected areas and transporting that
sediment to onshore or offshore areas for disposal. The three main types of dredges are
mechanical dredges, hydraulic dredges, and airlift dredges. The selection of dredge type
generally is related to the sediment type, the size of the area to be dredged, and the aquatic
resources present.
At operating nuclear power plants, dredging is performed infrequently, if at all. For example,
dredging at the Peach Bottom plant is performed approximately once every 20 years over a total
area of approximately 6 ac (2.4 ha) (NRC 2003b). When it was operating, the Oyster Creek
plant dredged portions of either the intake or the discharge canals approximately every 10 years
(NRC 2007b). The Monticello plant requires dredging every 6 to 8 years (NRC 2006c). The
Surry plant is one exception; because of the tidal influence of the James River near the plant
and the site’s location on a peninsula within the river, dredging is performed every 3 to 4 years
(NRC 2020f).
Dredging results in the direct removal of soft bottom substrates along with infaunal and
epifaunal organisms of limited mobility inhabiting those substrates. Small organisms living within
and on the affected sediments are likely to be killed in the process. Smaller benthic
invertebrates, such as mollusks and crustaceans, may also be susceptible to entrainment into
the dredge head. Larger benthic individuals or those that are farther from the dredge head could
move away from the suction flow field to avoid being entrained. Thus, dredging can be expected
to cause short-term reductions in the biomass of benthic organisms. Dredging also creates
sediment plumes that increase water turbidity, which can adversely affect aquatic biota and
create short-term decreases in habitat quality during and after dredging. Turbidity primarily
affects liquid-breathing organisms, such as fish and shellfish, as well as aquatic plants, because
turbid conditions typically decrease photosynthetic capabilities. Turbidity levels associated with

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the sediment plumes of cutterhead dredges typically range from 11.5 to 282.0 milligrams per
liter (mg/L) with decreasing concentrations at greater distances from the dredge head
(Nightingale and Simenstad 2001). Studies of benthic community recovery following dredging
indicate that species abundance and diversity can recover within several years of dredging
(Michel et al. 2013). Specifically, within temperate, shallow water regions containing a
combination of sand, silt, or clay substrate, benthic communities can recover in 1 to 11 months,
according to studies reviewed by Wilber et al. (2006). Recovery of benthic communities
following dredging also tends to be faster in areas exposed to periodic disturbances, such as
tidally influenced habitats (Diaz 1994).
With respect to turbidity and sedimentation caused by dredging, studies of the effects of turbid
waters on fish suggest that concentrations of suspended solids can reach thousands of
milligrams per liter before an acute toxic reaction occurs (Burton 1993 as cited in NMFS 2014a).
In a literature review, Burton (1993 as cited in NMFS 2014a) demonstrated that lethal effects on
fish due to turbid waters can occur at levels between 580 mg/L and 700,000 mg/L, depending
on the species. Studies of striped bass, an anadromous species, showed that pre-spawners did
not avoid concentrations of 954 to 1,920 mg/L to reach spawning sites (Summerfelt and Mosier
1976; Combs 1979). Sedimentation could also affect benthic macroinvertebrates. However,
these individuals could avoid the plume or uncover themselves from any sedimentation
experienced during dredging such that these impacts would be negligible and short term in
nature.
Sediments may be contaminated with a variety of pollutants from agricultural runoff and
stormwater runoff from impervious surfaces. These pollutants can also be introduced to
waterways from point sources, such as combined sewer overflows, municipal and industrial
discharges, and spills. Contaminants that have accumulated in buried layers of sediment
are often less readily bioavailable or less chemically active (EPA 2004). Depending on the
concentrations of specific contaminants in accumulated sediments, dredging could increase
the bioavailability of those contaminants if they are resuspended in the water column
(Petersen et al. 1997; Su et al. 2002; EPA 2004).
Dredging would require nuclear power plant licensees to obtain permits from the USACE under
CWA Section 404. BMPs and conditions associated with these permits would minimize impacts
on the ecological environment. The granting of such permits would also require the USACE to
conduct its own environmental reviews prior to undertaking dredging.
Initial LR or SLR would continue current operating conditions and environmental stressors
rather than introduce wholly new impacts. Therefore, the impacts of current operations and
license renewal on aquatic resources would be similar. For these reasons, the effects of
dredging on aquatic resources would be minor and would neither destabilize nor noticeably alter
any important attribute of the aquatic environment during initial LR or SLR terms of any nuclear
power plants. The NRC assumes that nuclear power plants would continue to implement site
environmental procedures and would obtain any necessary permits for dredging activities.
Implementation of such controls would further reduce or mitigate potential effects. The staff
reviewed information in scientific literature and from SEISs (for initial LRs and SLRs) completed
since development of the 2013 LR GEIS and identified no new information or situations that
would result in different impacts for this issue for either an initial LR or SLR term.
The NRC concludes that effects of dredging on aquatic resources during the license renewal
term (initial LR or SLR) would be SMALL for all nuclear power plants. This is a Category 1
issue.

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4.6.1.2.10 Water Use Conflicts with Aquatic Resources (Plants with Cooling Ponds or Cooling
Towers Using Makeup Water from a River)
The issue concerns water use conflicts that may arise at nuclear power plants with cooling
ponds or cooling towers that use makeup water from a river and how those conflicts could affect
aquatic resources during an initial LR or SLR term.
In the 1996 and 2013 LR GEISs, the NRC determined that the impacts of water use conflicts on
aquatic resources would be SMALL at many nuclear power plants but that these impacts could
be MODERATE at some plants. Therefore, this was considered a Category 2 issue for nuclear
power plants with cooling ponds or cooling towers using makeup water from a river. The
1996 LR GEIS addressed cooling towers that withdraw from small rivers with low flow; the
2013 LR GEIS expanded this issue to include all cooling towers that withdraw from rivers.
Notably, this issue also applies to nuclear power plants with hybrid cooling systems that
withdraw makeup water from a river (i.e., once-through cooling systems with helper cooling
towers) (e.g., NRC 2020g).
Nuclear power plant cooling systems may compete with other users relying on surface water
resources, including downstream municipal, agricultural, or industrial users. Closed-cycle
cooling is not completely closed because the system discharges blowdown water to a surface
waterbody and withdraws water for makeup of both the consumptive water loss due to
evaporation and drift (for cooling towers) and blowdown discharge. For plants using cooling
towers, while the volume of surface water withdrawn is substantially less than once-through
systems for a similarly sized nuclear power plant, the makeup water needed to replenish the
consumptive loss of water to evaporation can be significant. Cooling ponds also require makeup
water. Section 4.5.1.1.9 addresses factors relevant to water use conflicts at nuclear power
plants in detail. Water use conflicts with aquatic resources could occur when water that supports
these resources is diminished by a combination of anthropogenic uses.
Consumptive use by nuclear power plants with cooling ponds or cooling towers using makeup
water from a river during the license renewal term is not expected to change unless power
uprates, with associated increases in water use, occur. Such uprates would require separate
NRC review and approval. Any river, regardless of size, can experience low-flow conditions of
varying severity during periods of drought and changing conditions in the affected watershed,
such as upstream diversions and use of river water. However, the direct impacts on instream
flow and potential water availability for other users from nuclear power plant surface water
withdrawals are greater for small (i.e., low flow) rivers.
To date, the NRC has identified water use conflicts with aquatic resources at only one nuclear
power plant: the Wolf Creek plant in Kansas. This plant uses Coffee County Lake for cooling,
and makeup water for the lake is drawn from the Neosho River downstream of John Redmond
Reservoir (NRC 2008a). The Neosho River is a small river with especially low water flow during
drought conditions. During the license renewal review, the NRC found that the aquatic
communities in the Neosho River downstream included the federally endangered Neosho
madtom, a small species of catfish, and that this species could be adversely affected by the
nuclear power plant’s water use during periods when the lake level is low and makeup water is
obtained from the Neosho River. The NRC concluded that water use conflicts would be SMALL
to MODERATE for this nuclear power plant. As part of the NRC’s ESA consultation with the
FWS, the Wolf Creek plant developed and implemented a water level management plan for
Coffey County Lake, which includes withdrawing makeup water proactively during high river
flows in order to support downstream populations of the Neosho madtom (FWS 2012). This plan

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effectively mitigated not only water use conflicts that the Neosho madtom might experience, but
also the effects that the entire downstream aquatic community might experience from the plant’s
cooling water withdrawals. The NRC has identified no concerns about water use conflicts with
aquatic resources at any other nuclear power plant with cooling ponds or cooling towers.
The staff reviewed information from SEISs (for initial LRs and SLRs) completed since
development of the 2013 LR GEIS. In summary, water use conflicts during an initial LR or
SLR term depend on numerous site-specific factors, including the ecological setting of the plant;
the consumptive use of other municipal, agricultural, or industrial water users; and the aquatic
resources present in the area. Water use conflicts with aquatic resources would be SMALL at
most nuclear power plants with cooling ponds or cooling towers that withdraw makeup from a
river but may be MODERATE at some plants. Therefore, a generic determination of potential
impacts on terrestrial resources from continued operations during a license renewal term is not
possible.
The NRC concludes that water use conflicts on aquatic resources during the license renewal
term (initial LR or SLR) could be SMALL or MODERATE at nuclear power plants with cooling
ponds or cooling towers using makeup water from a river. This is a Category 2 issue.
4.6.1.2.11 Non-Cooling System Impacts on Aquatic Resources
This issue concerns the effects of nuclear power plant operations on aquatic resources during
an initial LR or SLR term that are unrelated to operation of the cooling system. Such activities
include landscape and grounds maintenance, stormwater management, and ground-disturbing
activities that could directly disturb aquatic habitat or cause runoff or sedimentation. These
impacts are expected to be like past and ongoing impacts that aquatic resources are already
experiencing at the nuclear power plant site.
In the 1996 LR GEIS, the NRC evaluated the impacts of refurbishment on aquatic resources. In
the 2013 LR GEIS, the NRC expanded this issue to include impacts of other site activities,
unrelated to cooling system operation, that may affect aquatic resources. In both the 1996 and
2013 LR GEISs, the NRC concluded that effects would be SMALL at all nuclear power plants.
Therefore, these were considered Category 1 issues for all nuclear power plants. This LR GEIS
refines the title of this issue from “Effects on aquatic resources (non-cooling system impacts)” to
“Non-cooling system impacts on aquatic resources” for clarity and consistency with other
ecological resource LR GEIS issue titles.
Industrial-use portions of nuclear power plant sites are typically maintained as modified habitats
with lawns and other landscaped areas; these areas typically do not include natural aquatic
features. Nonindustrial-use portions of nuclear power plant sites may include natural aquatic
habitats, such as streams, ponds, lakes, and usually interface with larger waterbodies, such as
rivers, reservoirs, estuaries, bays, or the ocean. These habitats may be undisturbed or in
various degrees of disturbance (e.g., dammed reservoirs, human-made cooling lakes, and
channelized rivers).
Certain areas may also be managed to preserve natural resources, either privately by the
nuclear power plant operator or in conjunction with local, State, or Federal agencies. For
instance, approximately 13,000 ac (5,300 ha) of land to the south and west of the Turkey Point
site in Florida is part of the Everglades Mitigation Bank (NRC 2019c). Under the guidance of
Federal and State agencies, Florida Power and Light Company creates, restores, and enhances
this habitat to provide compensatory mitigation of wetland losses elsewhere. At the Harris plant

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in North Carolina, Duke Energy leases land, including part of Harris Lake, to Wake County
which co-manages the area with the North Carolina Wildlife Resources Commission for natural
resource preservation and recreational opportunities (Duke Energy 2017). Continued
conservation efforts would have beneficial effects on the local aquatic ecology.
The characteristics of aquatic habitats and communities on nuclear power plant sites have
generally developed in response to many years of plant operations and maintenance. While
some communities may have reached a relatively stable condition, some may have continued to
change gradually over time. Operations and maintenance activities during the license renewal
term are expected to be like current activities (see Section 2.1.1).
In the 1996 and 2013 LR GEISs, the NRC staff anticipated that nuclear power plants may
require refurbishment to support continued operations during a license renewal term (see
Section 2.1.2). However, refurbishment has not typically been necessary for license renewal.
Only two nuclear power plants have undertaken refurbishment as part of license renewal
(Beaver Valley and Three Mile Island [no longer operating], both of which are located in
Pennsylvania) (NRC 2009a, NRC 2009b). In addition to refurbishment, license renewal could
require construction of additional onsite spent fuel storage. Refurbishment or spent fuel storage
construction could require new parking areas for workers as well as new access roads,
buildings, and facilities. Temporary project support areas for equipment storage, overflow
parking, and material laydown areas could also be required.
Any activities that require construction or involve ground disturbance could affect nearby aquatic
features and habitats. Surface water habitats could be directly affected if activities cause ponds
to be drained or blocked, or streams to be redirected. Depending on the size and nature of the
waterbody affected, aquatic plants and animals could be displaced or killed, or the community
structure within the waterbody could be altered. Indirect effects include erosion and
sedimentation, both of which are typically proportional to the amount of surface disturbance,
slope of the disturbed land, condition of the area at the time of disturbance, and proximity to
aquatic habitats. Chemical contamination could also occur from fuel or lubricant spills. If impacts
to aquatic habitats are anticipated, these activities would require nuclear power plant licensees
to obtain applicable permits under the CWA, to develop stormwater management plans and spill
prevention plans, and to implement BMPs to minimize soil erosion and deposition. Standard
BMPs often include buffer zones surrounding waterways, aquatic features, and wetlands. BMPs
and conditions associated with necessary permits would minimize impacts on the ecological
environment. To date, the NRC staff has not identified noticeable or detectable impacts on
aquatic features or habitats in connection with construction or ground disturbance during the
license renewal period at any nuclear power plant.
Many nuclear power plant operators have developed site or fleet-wide environmental review
procedures that help workers identify and avoid impacts on the ecological environment when
performing site activities. These procedures generally include checklists to help identify potential
effects and required permits and BMPs to minimize the affected area. BMPs relevant to aquatic
resources may include measures to control runoff, erosion, and sedimentation from project
sites; revegetate disturbed areas to control future erosion; and avoid the use of chemicals or
machinery near waterways and aquatic features. Proper implementation of environmental
procedures and BMPs would minimize or mitigate potential effects on aquatic resources during
the license renewal term. Many activities that could affect aquatic habitats would also require
nuclear power plant licensees to obtain Federal permits under CWA Section 404, which would
include conditions to minimize or mitigate impacts on affected waterways.

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Some utilities are members of the Wildlife Habitat Council, which helps corporations manage
their land for broad-based biodiversity enhancement and conservation. As part of membership,
sites develop wildlife management plans that include a comprehensive strategy for enhancing
and conserving site ecological resources. For instance, at the Braidwood plant in Illinois, Exelon
places artificial habitats in Braidwood Lake to create microhabitats and support fish populations,
especially largemouth bass (Micropterus salmoides) (Exelon 2012). At the LaSalle plant in
Illinois, Exelon participates in supplemental stocking of a variety of warm and cool water fish
that are raised in an onsite hatchery (Exelon 2012). To maintain membership, sites must
undertake projects that promote native biodiversity, gather data on conservation efforts, and
report on their progress. Other nuclear power plant sites that maintain Wildlife Habitat Council
membership include the Byron, Calvert Cliffs, Clinton, Dresden, Fitzpatrick, Ginna, Limerick,
Nine Mile Point, Peach Bottom, and Quad Cities plants. Continued participation in this or similar
environmental conservation organizations would minimize or mitigate potential effects on
aquatic resources during the license renewal term.
Initial LR or SLR would continue current operating conditions and environmental stressors
rather than introduce wholly new impacts. Therefore, the impacts of current operations and
license renewal on aquatic resources would be similar. For these reasons, the effects of site
activities, unrelated to cooling system operation, would be minor and would neither destabilize
nor noticeably alter any important attribute of the aquatic environment during initial LR or
SLR terms of any nuclear power plants. The NRC assumes that nuclear power plants would
continue to implement site environmental procedures and would obtain any necessary permits
for activities that could affect waterways or aquatic features. Implementation of such controls
would further reduce or mitigate potential effects. The staff reviewed information in scientific
literature and from SEISs (for initial LRs and SLRs) completed since development of the
2013 LR GEIS and identified no new information or situations that would result in different
impacts for this issue for either an initial LR or SLR term. The NRC concludes that non-cooling
system effects on aquatic resources during the license renewal term (initial LR or SLR) would
be SMALL for all nuclear power plants. This is a Category 1 issue.
4.6.1.2.12 Impacts of Transmission Line Right-of-Way (ROW) Management on Aquatic
Resources
This issue concerns the effects of transmission line ROW management on aquatic plants and
animals during an initial LR or SLR term.
In the 1996 and 2013 LR GEISs, the NRC determined that transmission line ROW maintenance
impacts would be SMALL at all nuclear power plants. Therefore, this was considered a
Category 1 issue for all nuclear power plants.
When this issue was originally contemplated in the 1996 LR GEIS, the NRC considered as part
of its plant-specific license renewal reviews all transmission lines that were constructed to
connect a nuclear power plant to the regional electric grid. However, in the 2013 LR GEIS, the
NRC clarified that the transmission lines relevant to license renewal include only the lines that
connect the nuclear power plant to the first substation that feeds into the regional power
distribution system (see Section 3.1.7). Typically, the first substation is located on the nuclear
power plant property within the primary industrial-use area. This decision was informed by the
fact that many of the transmission lines that were constructed with nuclear power plants are now
interconnected with the regional electric grid and would remain energized regardless of initial LR
or SLR. Accordingly, the discussion of this issue in this LR GEIS is brief because in-scope
transmission lines for license renewal tend to occupy only industrial-use or other developed

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portions of nuclear power plant sites. Therefore, effects on aquatic plants and animals are
generally negligible. The 2013 LR GEIS provides further background about this issue and
discusses it in more detail.
Transmission line management can directly disturb aquatic habitats if ROWs traverse aquatic
features and heavy machinery is used in these areas. Heavy equipment can also compact soils,
which can affect soil quality and reduce infiltration to shallow groundwater, resulting in runoff
and erosion in nearby aquatic habitats. Chemical herbicides applied in ROWs can be
transported to nearby aquatic habitats through precipitation and runoff. For small streams, trees
may grow sufficiently between cutting cycles to provide shading and support microhabitats. Tree
removal to maintain appropriate transmission line clearance could alter the suitability of habitats
for fish and other aquatic organisms and locally increase water temperatures.
Most nuclear power plants maintain procedures to minimize or mitigate the potential impacts of
ROW management. For instance, heavy machinery and herbicide use is often prohibited in or
near wetlands or surface waters. Vegetated buffers are often maintained near surface waters.
Procedures also often include checklists to ensure that workers obtain necessary local, State, or
Federal permits if work could affect protected resources.
Aquatic communities in transmission line ROWs have been exposed to many years of
transmission line operation and have acclimated to regular ROW maintenance. Initial LR or SLR
would continue current operating conditions and environmental stressors rather than introduce
wholly new impacts. Therefore, the impacts of current operations and license renewal on
aquatic resources would be similar. Further, and as stated above, in-scope transmission lines
for license renewal tend to occupy only industrial-use or other developed portions of nuclear
power plant sites and, therefore, the effects of ROW maintenance on aquatic plants and animals
during an initial LR or SLR term would be negligible. The staff reviewed information in scientific
literature and from SEISs (for initial LRs and SLRs) completed since development of the
2013 LR GEIS and identified no new information or situations that would result in different
impacts for this issue for either an initial LR or SLR term. The NRC concludes that the
transmission line ROW maintenance impacts on aquatic resources during the license renewal
term (initial LR or SLR) would be SMALL for all nuclear power plants. This is a Category 1
issue.
4.6.1.3

Federally Protected Ecological Resources

The NRC must consider the effects of its actions on ecological resources protected under
several Federal statutes and must consult with the FWS or the NOAA prior to taking action in
cases where an agency action may affect those resources. These statutes include the following:
• the Endangered Species Act of 1973 (16 U.S.C. § 1531 et seq.),
• the Magnuson-Stevens Fishery Conservation and Management Act (MSA) (16 U.S.C. § 1801
et seq.), as amended by the Sustainable Fisheries Act of 1996, and
• the National Marine Sanctuaries Act (NMSA) (16 U.S.C. § 1431 et seq.).
Section 3.6.3 describes each of these statutes and the ecological resources protected under
them. During initial LR and SLR reviews, the NRC may be required to consult under one or
more of these statutes, depending on the ecological setting of the nuclear power plant and the
federally protected species and habitats that may be affected by continued operation of the
plant. Under the ESA, the NRC may be required to consult with FWS, NMFS, or both.

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Individually, these agencies are also referred to as the Service or jointly as the Services. The
NRC addresses the ecological resources that each type of interagency consultation addresses
as four separate issues in the subsections below. These issues are:
• Endangered Species Act: federally listed species and critical habitats under U.S. Fish and
Wildlife Service jurisdiction15
• Endangered Species Act: federally listed species and critical habitats under National Marine
Fisheries Service jurisdiction15
• Magnuson-Stevens Fishery Conservation and Management Act: essential fish habitat15
• National Marine Sanctuaries Act: sanctuary resources
4.6.1.3.1

Endangered Species Act: Federally Listed Species and Critical Habitats Under
U.S. Fish and Wildlife Service Jurisdiction

This issue concerns the potential effects of continued nuclear power plant operation and any
refurbishment during an initial LR or SLR term on federally listed species and critical habitats
protected under the ESA and under the jurisdiction of the FWS.
Under the ESA, the FWS is responsible for listing and managing terrestrial and freshwater
species and designating critical habitat of these species. Continued operation of a nuclear
power plant during an initial LR or SLR term could affect these species and their habitat. Listed
species are likely to occur near all operating nuclear power plants. However, the potential for a
given species to occur in the action area of a specific nuclear power plant depends on the life
history, habitat requirements, and distribution of the species and the ecological environment
present on or near the plant site. Section 3.6.3.1 describes some of the listed species and
critical habitats under FWS jurisdiction that the NRC has analyzed during past license renewal
reviews and the relevant environmental stressors related to license renewal.
Potential effects of particular concern for listed terrestrial species, including bats, birds,
mammals, reptiles, amphibians, and invertebrates, include the following:
• habitat loss, degradation, disturbance, or fragmentation resulting from construction,
refurbishment, or other site activities, including site maintenance and infrastructure repairs
• noise and vibration and general human disturbance
• mortality or injury from collisions with plant structures and vehicles
Additionally, terrestrial listed species and their habitats can be adversely affected by any of the
factors described in Section 4.6.1.1 relevant to terrestrial resources. However, the magnitude
and significance of such impacts can be greater for listed species because—by virtue of being
eligible for Federal listing—these species are significantly more sensitive to environmental
stressors because their populations are already in decline. Similarly, critical habitats are
afforded special protections because they are critical to the preservation of the listed species.

15

These issues have been separated from one 2013 LR GEIS issue into distinct issues that individually
address specific categories of federally protected ecological resources that may require separate
interagency consultation.

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Potential effects of particular concern for listed aquatic species, including fish, shellfish and
other aquatic invertebrates, and sea turtles, include the following:
• impingement (including entrapment) and entrainment
• thermal effects
• exposure to radionuclides and other contaminants
• reduction in available food resources due to IM&E or thermal effects on prey species
• effects associated with maintenance dredging
Additionally, aquatic listed species and their habitats can be adversely affected by any of the
factors described in Section 4.6.1.2 relevant to aquatic resources. As noted above, the
magnitude and significance of such effects can be greater for listed species and critical habitats
than for other aquatic resources.
As established in the 2013 LR GEIS, the NRC reports findings under the ESA in accordance
with terminology used in the ESA and its implementing regulations (see Table 4.6-6). Individual
effect determinations are made for each listed species and critical habitat, so the number of
ESA findings for a given license renewal will depend on the number of listed species and critical
habitats present in the action area. The “action area” is defined in the Services’ regulations as
all areas to be affected directly or indirectly by the Federal action and not merely the immediate
area involved in the action (50 CFR 402.02). Table 3.6-2 and Table 3.6-5 identify the NRC’s
findings for listed species and critical habitats evaluated during initial LR and SLR environmental
reviews conducted since the 2013 LR GEIS.
Table 4.6-6 Possible Endangered Species Act Effect Determinations
Listed Species
“may affect and is likely to
adversely affect”
“may affect but is not likely to
adversely affect”
“no effect”

Proposed Species
“may affect and is likely to
adversely affect”
“may affect but is not likely to
adversely affect”
“no effect”

Designated or Proposed Critical
Habitat
“is likely to destroy or adversely
modify”
“is not likely to destroy or
adversely modify”
“no effect”

Depending on the NRC’s ESA effect determinations, the NRC may be required to consult with
the Services under ESA Section 7(a)(2). The Services maintain joint regulations that implement
ESA Section 7 at 50 CFR Part 402, “Interagency Cooperation – Endangered Species Act of
1973, as Amended.” Subpart B prescribes the Section 7 interagency consultation requirements.
The NRC also relies upon the Services’ detailed procedural guidance for conducting Section 7
consultation in Endangered Species Consultation Handbook: Procedures for Conducting
Consultation and Conference Activities Under Section 7 of the Endangered Species Act
(FWS/NMFS 1998).
Under ESA Section 7, Federal agencies must consult with the Services for actions that “may
affect” federally listed species and critical habitats and to ensure that their actions do not
jeopardize the continued existence of those species or destroy or adversely modify those
habitats. Section 7 consultation may be informal or formal. Generally, the appropriate type of
consultation is related to the effect determinations made by the Federal agency. For proposed
species and proposed critical habitats (the species or habitats for which the Services have
issued proposed listing or designation rules, but for which final rules have yet to be issued or

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adopted), the regulations prescribe a process called a conference. NUREG-1555,
Supplement 1, Revision 2, Standard Review Plans for Environmental Reviews for Nuclear
Power Plants, Supplement 1: Operating License Renewal (NRC 2024), describes informal
consultation, formal consultation, and conference in detail. The Services’ regulations also allow
for early, special, and emergency consultations. However, instances that would necessitate
these types of consultation are unlikely to arise for license renewal. Table 4.6-7 summarizes the
appropriate type of consultation or conference for each possible effect determination.
Table 4.6-7

Appropriate Type of Consultation by Endangered Species Act Effect
Determination

Type of Consultation
Formal Consultation

Informal Consultation

Conference

No Consultation or
Conference

Listed Species
“may affect and is
likely to adversely
affect”
“may affect but is
not likely to
adversely affect”
N/A

“no effect”

Proposed
Species
N/A

N/A

“may affect and is
likely to adversely
affect”
“may affect but is
not likely to
adversely affect”(a)
or
“no effect”

Designated
Critical Habitats

Proposed Critical
Habitats

“is likely to destroy
N/A
or adversely
modify”
“is not likely to
N/A
destroy or
adversely modify”
N/A
“is likely to destroy
or adversely
modify”
“no effect”
“is not likely to
destroy or
adversely modify”
or
“no effect”

N/A = not applicable.
(a) Although not required, it is a best practice to confer with the Services when a proposed action may affect but is
not likely to adversely affect proposed species.

In cases where adverse effects on listed species or critical habitats are possible, the NRC staff
has engaged the Services in formal ESA Section 7 consultation as part of the license renewal
review and obtained a biological opinion. The FWS has issued one biological opinion in
connection with initial LR and SLR environmental reviews conducted since the publication of the
2013 LR GEIS. This biological opinion is for continued operation of the Turkey Point plant during
an SLR term, and it addresses the American crocodile (Crocodylus acutus), its critical habitat,
and the eastern indigo snake (Drymarchon corais couperi) (FWS 2019a, FWS 2022a). The
incidental take statement of the opinion allows for a specified amount of take of these species
that is incidental to, and not the purpose of, carrying out the Federal action of license renewal,
as well as reasonable and prudent measures and terms and conditions to minimize such take.
In accordance with these requirements, the Turkey Point plant monitors and reports the effects
of continued operation under the license renewal term to the FWS and the NRC. Section 3.6.3
discusses biological opinions in more detail.
The staff reviewed information from SEISs (for initial LRs and SLRs) completed since
development of the 2013 LR GEIS. In summary, the potential effects of continued nuclear power
plant operation during an initial LR or SLR term depends upon numerous site-specific factors,
including the ecological setting of the plant; the listed species and critical habitats present in the
action area; and plant-specific factors related to operations, including water withdrawal, effluent
discharges, and refurbishment and other ground-disturbing activities. Section 7 of the ESA
requires that Federal agencies consult with the Services for actions that “may affect” federally

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listed species and critical habitats. Additionally, listing status is not static, and the Services
frequently issue new rules to list or delist species and designate or remove critical habitats.
Therefore, a generic determination of potential impacts on listed species and critical habitats
under FWS jurisdiction during a nuclear power plant’s license renewal term is not possible. The
NRC would need to perform a plant-specific impact assessment as part of each initial LR or
SLR environmental review to determine the potential effects on these resources and consult
with the FWS, as appropriate. Consequently, this is a Category 2 issue.
4.6.1.3.2

Endangered Species Act: Federally Listed Species and Critical Habitats Under
National Marine Fisheries Service Jurisdiction

This issue concerns the potential effects of continued nuclear power plant operation and any
refurbishment during an initial LR or SLR term on federally listed species and critical habitats
protected under the ESA and under the jurisdiction of NMFS.
Under the ESA, NMFS is responsible for listing and managing marine and anadromous species
and designating critical habitat of these species. Continued operation of a nuclear power plant
during an initial LR or SLR term could affect these species and their habitat. The potential for a
given species to occur in the action area of a specific nuclear power plant depends on the life
history, habitat requirements, and distribution of that species and the ecological environment
present on or near the power plant site. In general, listed species and critical habitats under
NMFS jurisdiction are only of concern at nuclear power plants that withdraw or discharge from
estuarine or marine waters. However, anadromous listed species under NMFS jurisdiction may
be seasonally present in the action area of plants located within freshwater reaches of rivers
well upstream of the saltwater interface. For instance, the Columbia plant in Washington
withdraws from and discharges to the Columbia River at approximately river mile 352 (river
kilometer 566). During the NRC’s license renewal review, the NRC consulted with NMFS
concerning Upper Columbia River spring run chinook salmon (Oncorhynchus tshawytscha) and
Upper Columbia River steelhead (O. mykiss) due to these species’ susceptibility to impingement
on the intake screens or entrainment into the intake system. These species migrate past the
plant seasonally as fry, which are only a few centimeters in length at this life stage
(NRC 2012a).
The discussion of potential effects on listed species and critical habitats under FWS jurisdiction
provided above in Section 4.6.1.3.1 also applies to this issue. As established in the 2013
LR GEIS, the NRC reports findings under the ESA in accordance with terminology used in the
ESA and its implementing regulations (see Table 4.6-6). Depending on the NRC’s ESA effect
determinations, the NRC may be required to consult with NMFS under ESA Section 7
(see Table 4.6-7).
Since the publication of the 2013 LR GEIS, NMFS has issued several biological opinions in
connection with nuclear power plant operation during a license renewal term. These include the
following:
• Indian Point plant (no longer operating) biological opinion addressing the effects of continued
operation and decommissioning on shortnose sturgeon (Acipenser brevirostrum), Atlantic
sturgeon (A. oxyrinchus oxyrinchus), and critical habitat of the New York Bight distinct
population segment of Atlantic sturgeon (NMFS 2013, NMFS 2018a, NMFS 2018b, NMFS
2020a)

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• Salem plant and Hope Creek plant biological opinions addressing the effects of continued
operation on Atlantic sturgeon; shortnose sturgeon; and green (Chelonia mydas), Kemp’s
(Lepidochelys kempii), and loggerhead (Caretta caretta) sea turtles (NMFS 2014c,
NMFS 2018c, NMFS 2023)
• St. Lucie plant biological opinions addressing the effects of continued operation on green,
hawksbill (Eretmochelys imbricata), Kemp’s, leatherback (Dermochelys coriacea), and
loggerhead sea turtles and smalltooth sawfish (Pristis pectinata) (NMFS 2016, NMFS 2022b)
• Columbia plant biological opinion addressing the effects of continued operation on Upper
Columbia River spring run chinook salmon and Upper Columbia River steelhead
(NMFS 2017)
• Oyster Creek plant (no longer operating) biological opinion addressing the effects of
continued operation and decommissioning on green, Kemp’s, and loggerhead sea turtles
(NRC 2020b)
The incidental take statements of these opinions allow for a specified amount of take of listed
species that is incidental to, and not the purpose of, carrying out the Federal action of license
renewal, as well as reasonable and prudent measures and terms and conditions to minimize
such take. In accordance with these requirements, these plants monitor and report the effects of
continued operation under the license renewal term to the NMFS and the NRC. Notably, two of
these opinions (for the Indian Point and Oyster Creek plants) also address the effects of
shutdown and decommissioning. Section 3.6.3 discusses these and other biological opinions in
more detail.
The staff reviewed information from SEISs (for initial LRs and SLRs) completed since
development of the 2013 LR GEIS. In summary, the potential effects of continued nuclear power
plant operation during an initial LR or SLR term depend on numerous site-specific factors,
including the ecological setting of the plant; the listed species and critical habitats present in the
action area; and plant-specific factors related to operations, including water withdrawal, effluent
discharges, and refurbishment and other ground-disturbing activities. Section 7 of the ESA
requires that Federal agencies consult with the Services for actions that “may affect” federally
listed species and critical habitats. Additionally, listing status is not static, and the Services
frequently issue new rules to list or delist species and designate or remove critical habitats.
Therefore, a generic determination of potential impacts on listed species and critical habitats
under NMFS jurisdiction during a nuclear power plant’s license renewal term is not possible.
The NRC would need to perform a plant-specific impact assessment as part of each initial LR or
SLR environmental review to determine the potential effects on these resources and consult
with NMFS, as appropriate. Consequently, this is a Category 2 issue.
4.6.1.3.3

Magnuson-Stevens Act: Essential Fish Habitat

This issue concerns the potential effects of continued nuclear power plant operation and any
refurbishment during an initial LR or SLR term on essential fish habitat (EFH) protected under
the MSA.
Under the MSA, the Fishery Management Councils, in conjunction with NMFS, designate areas
of EFH and manage marine resources within those areas. Within EFH, habitat areas of
particular concern (HAPCs) may be designated if the area meets certain additional criteria.
Continued operation of a nuclear power plant during an initial LR or SLR term could affect EFH,
including HAPCs. EFH may occur at nuclear power plants located on or near estuaries, coastal

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inlets and bays, and the ocean. EFH is generally not relevant for license renewal reviews of
plants located on rivers well above the saltwater interface or confluence with marine waters;
plants located on freshwater lakes, including the Great Lakes; or at plants that draw cooling
water from human-made cooling ponds or canals that do not hydrologically connect to natural
surface waters. One exception is in cases where a plant draws cooling water from the
freshwater portion of a river that is inhabited by diadromous prey of federally managed species
(herein referred to as “EFH species”) with designated EFH downstream of the plant.
Section 3.6.3.2 discusses this in more detail and provides examples of license renewal reviews
where this caveat has applied; it also describes EFH that the NRC has analyzed during other
past license renewal reviews and the relevant environmental stressors related to license
renewal.
EFH is assessed in terms of impacts on the habitat of each EFH species, life stage, and their
prey and each HAPC. Importantly, EFH effect determinations characterize the effects on the
habitat of the EFH species and their life stages. They do not characterize the effects on the
species or the life stages themselves. Similarly, effect determinations for EFH prey characterize
the effects on the prey as a food resource rather than the effects on the prey species
themselves. For instance, a proposed action that involves water withdrawal from a river for
cooling purposes could cause habitat loss (i.e., temporary or permanent physical loss of a
portion of the water column). Associated effluent discharge could cause chemical or biological
(i.e., temperature and dissolved oxygen content) alterations to the habitat. With respect to prey
species, water withdrawals could impinge or entrain prey organisms, which would represent a
reduction in available food resources for EFH species within that habitat. Potential effects of
particular concern for EFH include the following:
• physical removal of habitat through cooling water withdrawals
• physical alteration of habitat through heated effluent discharges
• chemical alteration of habitat through radionuclides and other contaminants in heated effluent
discharges
• physical removal of habitat through maintenance dredging
• reduction in the prey base of the habitat
Additionally, EFH can be adversely affected by any of the factors described in Section 4.6.1.2
relevant to aquatic resources. However, the magnitude and significance of such impacts can be
greater for EFH because—by virtue of being designated as EFH—these habitats are
significantly more sensitive to environmental stressors because the EFH species they support
are already experiencing many pressures that affect their spawning, breeding, feeding, or
growth.
As established in the 2013 LR GEIS, the NRC reports findings under the MSA in accordance
with terminology used in the MSA and its implementing regulations (see Table 4.6-8). Individual
effect determinations are made for the EFH of each life stage of each EFH species, so the
number of MSA findings for a given license renewal will depend on the number of EFH species
and life stages with EFH present in the area. For instance, a license renewal could result in no
adverse effects to EFH of eggs of Atlantic butterfish (Peprilus triacanthus), but could result in
minimal adverse effects to EFH of juveniles and adults of the same species. Table 3.6-6
identifies the NRC’s findings for EFH evaluated during initial LR and SLR environmental reviews
conducted since the publication of the 2013 LR GEIS.

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Table 4.6-8

Possible Essential Fish Habitat Effect Determinations

EFH Effect Determinations

Spatial Extent

Duration

“substantial adverse effects”
“more than minimal, but less than
substantial adverse effects”
“minimal adverse effects”

surface area, depth, and
seasonality described in writing
with explicit measurements, to
the extent possible, or pictorially
on a map

temporary versus permanent
short-term versus long-term

“no adverse effects”
EFH = essential fish habitat.

Depending on the NRC’s EFH effect determinations, the NRC may be required to consult with
NMFS under MSA Section 305(b). The NMFS maintains regulations that implement MSA
Section 305 at 50 CFR Part 600, “Magnuson-Stevens Act Provisions.” Subpart K of these
regulations prescribes the EFH interagency consultation requirements. Subpart J includes
definitions and other information relevant to EFH. The NRC also relies upon the NMFS’s
detailed procedural guidance for conducting EFH consultation in Essential Fish Habitat
Consultation Guidance (NMFS 2004a) and Preparing Essential Fish Habitat Assessments:
A Guide for Federal Action Agencies (NMFS 2004b).
EFH consultation may be abbreviated, expanded, or programmatic. Generally, the appropriate
type of consultation is related to effect determinations made by the Federal agency.
NUREG-1555, Supplement 1, Revision 2 (NRC 2024), describes informal consultation, formal
consultation, and conference in detail. The NMFS regulations also allow for general
concurrences concerning EFH. However, situations are rare in which a general concurrence
would apply to an NRC action. Table 4.6-9 summarizes the appropriate type of consultation for
each possible effect determination.
Table 4.6-9 Appropriate Type of Consultation by Type of Proposed Action and Essential
Fish Habitat Effect Determination
Types of Consultation

Type of Proposed Action

EFH Effect Determination

Abbreviated Consultation

individual proposed action

Expanded Consultation

individual proposed action

“minimal adverse effects”
or
“more than minimal, but less
than adverse effects”(a)
“substantial adverse effects”
or
“more than minimal, but less
than adverse effects”(a)
no more than “minimal adverse
effects” either individually or
cumulatively

Programmatic Consultation

No Consultation

proposed actions with a large number
of individual actions, such as
rulemakings or those involving
development of a GEIS
any

“no adverse effects”

EFH = essential fish habitat; GEIS = generic environmental impact statement.
(a) For this finding, the NRC should work with NMFS to determine whether abbreviated or expanded consultation is
most appropriate.

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In cases where adverse effects on EFH are possible, the NRC staff has engaged NMFS in
EFH consultation as part of the license renewal review and obtained EFH conservation
recommendations. The NMFS has developed EFH conservation recommendations in
connection with four initial LR and SLR environmental reviews conducted since the publication
of the 2013 LR GEIS: the Columbia (NMFS 2017), Seabrook (NMFS 2011), Limerick
(NMFS 2014b), and Surry (NMFS 2019) plant reviews. These recommendations are intended to
help an action agency avoid and minimize impacts on EFH and, when there is unavoidable
impact, offset this impact (NOAA 2023c). For instance, NMFS (2014b) recommended restricting
in-water maintenance work during certain parts of the year during the Limerick license renewal
term:
• “Avoid in-water maintenance work from March 1 to June 30 of each year to minimize adverse
effects on migrating and spawning activities of anadromous fish.”
If EFH consultation is conducted concurrently with ESA consultation, NMFS may make
recommendations based on requirements of the biological opinion. For instance, NMFS (2017)
made the following recommendations with respect to the Columbia plant license renewal:
(a) “Minimize adverse effects on water quality by monitoring and reporting as stated in term
and condition #1 in the accompanying [biological] opinion.”
(b) “Minimize the risk of artificial obstruction by conducting the entrainment and
impingement studies as stated in term and condition #2 in the accompanying [biological]
opinion.”
The NRC has a statutory obligation to reply to EFH conservation recommendations within
30 days of receiving the recommendations (50 CFR 600.920(k)(1)). A response must be
provided at least 10 days prior to the NRC’s issuance of a renewed license renewal if the
response is inconsistent with any of NMFS's recommendations, unless NMFS and NRC agree
to an alternative timeline (50 CFR 600.920(k)(1)).
The staff reviewed information from SEISs (for initial LRs and SLRs) completed since
development of the 2013 LR GEIS. In summary, the potential effects of continued nuclear power
plant operation during an initial LR or SLR term depends upon numerous site-specific factors,
including the ecological setting of the plant; the EFH present in the affected area, including
HAPCs; and plant-specific factors related to operations, including water withdrawal, effluent
discharges, and any other activities that may affect aquatic habitats during the license renewal
term, such as refurbishment or any in-water activities. Section 305(b) of the MSA requires that
Federal agencies consult with NMFS for actions that may adversely affect EFH. Additionally,
EFH status is not static. NMFS and the Fishery Management Councils frequently update
management plans for EFH species and issue new rules to designate or modify EFH and
HAPCs. Therefore, a generic determination of potential impacts on EFH during a nuclear power
plant’s license renewal term is not possible. The NRC would need to perform a plant-specific
impact assessment as part of each initial LR or SLR environmental review to determine the
potential effects on these resources and consult with NMFS, as appropriate. Consequently, this
is a Category 2 issue.
4.6.1.3.4

National Marine Sanctuaries Act: Sanctuary Resources

This issue concerns the potential effects of continued nuclear power plant operation and any
refurbishment during an initial LR or SLR term on sanctuary resources protected under the
NMSA.

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Under the NMSA, NOAA’s Office of National Marine Sanctuaries (ONMS) designates and
manages the National Marine Sanctuary System. Marine sanctuaries may occur near nuclear
power plants located on or near marine waters as well as the Great Lakes. Currently, five
operating nuclear power plants—Ginna, Nine Mile Point, and FitzPatrick on Lake Ontario; Point
Beach on Lake Michigan; and Turkey Point near Biscayne Bay—are located near designated or
proposed national marine sanctuaries (see Table 3.6-7).
Impacts on marine sanctuaries are broad ranging because such resources include any living or
nonliving resource of a national marine sanctuary. With respect to ecological sanctuary
resources, potential effects of particular concern include the following:
• impingement (including entrapment) and entrainment
• thermal effects
• exposure to radionuclides and other contaminants
• reduction in available food resources due to IM&E or thermal effects on prey species
• effects associated with maintenance dredging
Additionally, sanctuary resources can be adversely affected by any of the factors described in
Section 4.6.1.2 relevant to aquatic resources or, in the case of certain sanctuary resources,
such as seabirds, the factors described in Section 4.6.1.1 relevant to terrestrial resources.
However, the magnitude and significance of such impacts can be greater for sanctuary
resources because—by virtue of being part of a national marine sanctuary—these resources
are more sensitive to environmental stressors. Notably, because sanctuary resources can
include those that contribute to the recreational, ecological, historical, educational, cultural,
archaeological, scientific, or aesthetic value of the sanctuary, proper assessment of potential
impacts may require coordination with other environmental resource areas, such as visual
resources, socioeconomics, and historical and cultural resources. Table 4.6-10 provides
examples of types of sanctuary resources included in the regulatory definition at 15 CFR 922.3.
Table 4.6-10 Types of Sanctuary Resources
substratum of the area of the sanctuary
submerged features(a) and the surrounding seabed
carbonate rock, corals, and other bottom formations
coralline algae and other marine plants and algae
marine invertebrates
brine seep biota

phytoplankton and zooplankton
fish
seabirds
sea turtles and other marine reptiles
marine mammals
historic resources(b)

(a) Submerged features may include human-made features, such as artificial coral reef structures and shipwrecks.
(b) Because sanctuary resources include historic resources, this review necessitates coordination with the historic
and cultural resource review to determine whether any historic resources are present that would be relevant to
the NMSA consultation. In such cases, multiple NRC staff may be involved in discussions with the ONMS.

The NRC reports findings under the NMSA in accordance with terminology used in the NMSA
(see Table 4.6-11). Depending on the NRC’s effect determinations, the NRC may be required to
consult with ONMS under NMSA Section 304(d). Unlike ESA Section 7 or EFH consultation, for
which there are each several possible types of consultation depending on the specific
circumstances, the ONMS’s guidance prescribes only a single process for consultation. NMSA
consultation is required when a Federal agency determines that an action “is likely to destroy,

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cause the loss of, or injure” a sanctuary resource. Federal actions subject to consultation may
be inside or outside the boundary of a national marine sanctuary.
Table 4.6-11 Possible National Marine Sanctuaries Act Effect Determinations
“may affect and is likely to destroy, cause the loss of, or injure”
“may affect but is not likely to destroy, cause the loss of, or injure”
“no effect”

The NOAA has not promulgated regulations concerning NMSA Section 304(d). In 2008, NOAA
issued an advance notice of proposed rulemaking in the Federal Register soliciting comments
about whether development of regulations implementing certain aspects of the NMSA
Section 304(d) consultation provisions is appropriate (73 FR 50259). The NOAA later withdrew
its proposal in 2011. However, the ONMS has issued guidance for conducting NMSA
consultation, which the NRC relies upon, in Overview of Conducting Consultation Pursuant to
Section 304(d) of the National Marine Sanctuaries Act (NOAA 2009). NUREG-1555,
Supplement 1, Revision 2 (NRC 2024), describes NMSA consultation in detail.
The NRC staff has evaluated the potential impacts of license renewal on national marine
sanctuaries in two environmental reviews conducted since the publication of the 2013 LR GEIS:
Turkey Point and Point Beach plants, both of which were subsequent license renewals.
Section 3.6.3.3 summarizes these reviews. Neither license renewal ultimately required NMSA
consultation with ONMS. However, these reviews highlighted the need for the NRC to consider
potential impacts on sanctuary resources within national marine sanctuaries in its license
renewal reviews and to consult with ONMS, as appropriate.
If the initial LR or SLR would injure sanctuary resources, the NRC would consult with ONMS,
and ONMS would formulate recommended reasonable and prudent alternatives. In the context
of NMSA Section 304(d), these alternatives can best be understood as the actions necessary to
protect sanctuary resources. Alternatives generally focus on the location, timing, and methods
of the proposed action. For example, the ONMS may recommend that the proposed action be
conducted:
• at an alternate location, including a location outside the sanctuary(ies)
• during a different season or that it be delayed for a specified period of time
• with alternative equipment or procedures
• in some combination of these recommendations
If the ONMS provides the NRC with recommended alternatives, the NRC must discuss the
recommendations with the ONMS. If the NRC (or applicant) plans to fully implement the
recommended alternatives and fully incorporate them into the proposed action, the NRC need
not take any further action beyond this discussion to conclude the consultation. If the NRC (or
applicant) does not follow the recommended alternatives, the NRC must prepare a written
response that describes the reasons for not implementing the alternatives.
The staff reviewed information from SEISs (for initial LRs and SLRs) completed since
development of the 2013 LR GEIS. In summary, the potential effects of continued nuclear power
plant operation during an initial LR or SLR term depends upon numerous site-specific factors,

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including the ecological setting of the plant; the sanctuary resources present in the affected
area; and plant-specific factors related to operations, including water withdrawal, effluent
discharges, and any other activities that may affect sanctuary resources during the license
renewal term, such as refurbishment or any in-water activities. Section 304(d) of the NMSA
requires that Federal agencies consult with the ONMS for actions that may injure sanctuary
resources. Additionally, national marine sanctuary status is not static. The geographic extent of
existing sanctuaries may change or expand in the future, and NOAA is likely to designate new
sanctuaries as additional areas of conservation need are identified and assessed. Therefore, a
generic determination of potential impacts on sanctuary resources during a nuclear power
plant’s license renewal term is not possible. The NRC would need to perform a plant-specific
impact assessment as part of each initial LR or SLR environmental review to determine the
potential effects on these resources and consult with NMFS, as appropriate. Consequently, this
new issue is being established as a plant-specific, or Category 2 issue.

4.7
4.7.1

Historic and Cultural Resources
Environmental Consequences of the Proposed Action – Continued Operations
and Refurbishment Activities

For the issue of historic and cultural resources, the NRC evaluated the impact of continued
operations and refurbishment activities during the license renewal term on historic and cultural
resources located onsite and in transmission line ROWs. This issue was addressed in the
2013 LR GEIS (NRC 2013a), and it is a Category 2 issue. The issue has been updated to
include discussion of impacts on cultural resources that are not eligible for or listed in the
National Register of Historic Places that would also need to be considered during license
renewal reviews.
Section 106 of the National Historic Preservation Act (NHPA; 54 U.S.C. § 300101 et seq.)
requires Federal agencies to take into account the effects of their undertakings (e.g., initial LR
and SLR) on historic properties and consult with the appropriate parties as defined in
36 CFR 800.2. NEPA requires Federal agencies to consider the potential effects of their
actions on the “affected human environment,” which includes “aesthetic, historic, and cultural
resources.” As discussed in Section 3.7.2, the NRC fulfills its Section 106 requirements through
the NEPA process in accordance with 36 CFR 800.8(c).
Historic and cultural resources, especially archaeological sites, are sensitive to ground
disturbance and are nonrenewable. Even a small amount of ground disturbance (e.g., ground
clearing and grading) could affect a significant resource. Much of the information contained in
an archaeological site is derived from the spatial relationships between soil layers and
associated artifacts. Once these spatial relationships are altered, they can never be reclaimed.
Aboveground resources and traditional cultural properties are sensitive to impacts from
alterations in the viewshed.
Continued operations and refurbishment activities during the renewal term (i.e., initial LR and
SLR) can affect historic and cultural resources through (1) ground-disturbing activities
associated with plant operations and ongoing maintenance (e.g., construction of new parking
lots or buildings), landscaping, agricultural or other use of plant property; (2) activities
associated with transmission line maintenance (e.g., maintenance of access roads or removal of
danger trees); and (3) changes in the appearance of nuclear power plants and transmission
lines. License renewal environmental reviews have shown that the appearance of nuclear power

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plants and transmission lines has not changed significantly over time; therefore, additional
viewshed impacts on historic and cultural resources are not anticipated.
The NHPA requires the NRC to conduct a plant-specific assessment to determine whether
historic properties are present in the area of potential effects, and if so, whether the license
renewal (initial LR or SLR) would result in any adverse effect upon such properties. There are
three potential determinations (see 36 CFR 800.4) for plant-specific license renewal reviews:
• no historic properties present, the undertaking will have no effect to historic properties
• historic properties present, the undertaking will have no adverse effect upon them
• historic properties present, the undertaking will have an adverse effect upon one or more
historic properties (see 36 CFR 800.5)
For historic or cultural resources that do not meet the criteria to be considered a historic
property under the NHPA, the NRC will assess whether there would or would not be any
potential significant impacts on these resource through the NEPA process.
The staff reviewed information from SEISs (for initial LRs and SLRs) completed since
development of the 2013 LR GEIS. As discussed in Section 3.7, historic and cultural resources
vary widely from site to site; there is no generic way of determining their existence or
significance. Based on the information reviewed and the preceding discussion, the NRC
concludes that potential impacts from continued operations and refurbishment activities on
historic and cultural resources during the initial LR and SLR terms are unique to each nuclear
power plant site. Therefore, the impacts on historic and cultural resources cannot be determined
generically, and it is a Category 2 issue.

4.8
4.8.1

Socioeconomics
Environmental Consequences of the Proposed Action – Continued Operations
and Refurbishment Activities

Environmental reviews have shown that continued operations and refurbishment activities in
support of license renewal have had little to no socioeconomic effect on communities near
nuclear plants. Socioeconomic effects of power plant operations have become well established
and normal fluctuations in employment, income, and tax revenue have not altered the quality
and availability of community services and housing or increased traffic volumes.
License renewal applicants consistently indicate they have no plans to add operations workers,
and increased maintenance and safety inspection activities during the renewal term can be
managed using the current workforce. Consequently, people living near nuclear power plants
have not experienced any significant socioeconomic impact since construction and the onset of
reactor operations. In addition, refurbishment activities, including steam generator and vessel
head replacement, have been conducted during regularly scheduled power plant refueling and
maintenance outages.
The environmental review of socioeconomic impacts conducted for this LR GEIS revision
consists of five issues:
• employment and income, recreation, and tourism
• tax revenue

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• community services and education
• population and housing
• transportation
4.8.1.1

Employment and Income, Recreation, and Tourism

As explained in Section 3.8, the nuclear power plant and the communities that support it can be
described as a dynamic socioeconomic system. The communities provide the people, goods,
and services required to operate the nuclear power plant. Power plant operation, in turn,
provides employment and income, and pays for goods and services from the communities.
Employees receive income from the nuclear power plant in the form of wages, salaries, and
benefits. Employees and their families, in turn, spend this income on goods and services within
the community, thereby creating additional employment opportunities and income. In addition,
people and businesses in the community receive income for the goods and services sold to the
nuclear power plant. Payments for these goods and services create additional employment and
income opportunities within the community.
As previously discussed, the number of nuclear plant operations workers is not expected to
change, and license renewal environmental reviews have shown no need for additional workers.
In addition, refurbishment activities, including steam generator and vessel head replacement,
are conducted during regularly scheduled refueling and maintenance outages. Consequently,
employment levels at a nuclear power plant are not expected to change as a result of license
renewal.
Some communities experience seasonal transient population growth due to local tourism and
recreational activities. Income from tourism and recreational activities creates employment and
income opportunities in the communities around nuclear power plants. Communities located
near nuclear power plants in coastal regions, notably the D.C. Cook and Palisades plants
(Palisades was shut down in May of 2022) on the eastern shore of Lake Michigan, experience
summer and weekend population increases due to the recreational and tourism activities that
attract visitors. Some communities attract visitors interested in outdoor recreational activities,
such as camping, hiking, and skiing.
As discussed in Section 4.2.1.2, the NRC considered the aesthetic impacts of nuclear plant
operations and refurbishment activities potentially affecting tourism and recreational business
interests. The NRC concluded in the 1996 and 2013 LR GEISs that aesthetic impacts would be
SMALL for all nuclear plants and a Category 1 issue. This is primarily because the visual impact
occurred during and after construction, and the appearance of nuclear power plants is not
expected to change as a result of license renewal.
However, a case study performed for the 1996 LR GEIS found situations where nuclear power
plants have had a negative effect on the public. Negative perceptions were based on aesthetic
considerations (for instance, the nuclear plant is out of character or scale with the community
or the viewshed), physical environmental concerns, safety and perceived risk issues, an
anti-nuclear plant attitude, or an anti-nuclear outlook. It is believed that these negative
perceptions would persist regardless of any mitigation. Subsequently, license renewal
environmental reviews have not revealed any new information that would change this
perception.

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Nevertheless, the effects of power plant operations on employment, income, recreation, and
tourism are ongoing and have become well-established for all nuclear power plants. The
impacts from power plant operations during the license renewal term on employment and
income in communities near nuclear power plants are not expected to change from those
currently being experienced. In addition, tourism and recreational activities in the vicinity of
nuclear plants are not expected to change as a result of license renewal. Based on these
considerations, the NRC concludes impacts from continued nuclear plant operations during
initial LR and SLR terms and refurbishment on employment, income, recreation, and tourism
would be the same—SMALL for all nuclear plants. The staff reviewed information from SEISs
(for initial LRs and SLRs) completed since development of the 2013 LR GEIS and identified no
new information or situations that would result in different impacts for this issue for either an
initial LR or SLR term. Therefore, employment, income, recreation, and tourism impacts would
be SMALL for all nuclear plants and a Category 1 issue.
4.8.1.2

Tax Revenue

Nuclear power plants are an important source of tax revenue for many local governments and
public school districts. Property taxes or payments in lieu of (property) taxes (PILOTs) are the
principal source of tax revenue in many tax jurisdictions with nuclear power plants, although in
some jurisdictions, energy production is also taxed. County and municipal governments and
public school districts receive tax revenue either directly from the licensee, owner of the nuclear
plant, or indirectly through State tax and revenue-sharing programs.
Counties and municipal governments also receive revenue from sales taxes and fees paid by
the nuclear plant and its employees. Changes in the workforce and property taxes or PILOTs
paid to local governments and public schools can directly affect socioeconomic conditions in the
counties and communities near the nuclear power plant.
Environmental reviews have shown that refurbishment activities, such as steam generator and
vessel head replacement, have not had a noticeable effect on the assessed value of nuclear
plants, thus changes in tax revenues are not anticipated from these activities. Refurbishment
involving the one-for-one replacement of existing nuclear plant components and equipment are
generally not considered a taxable improvement. Also, property tax assessments; proprietary
PILOT stipulations, settlements, and agreements; and State tax laws are continually changing
the amount of taxes paid to tax jurisdictions by nuclear plant owners. These tax revenue
changes are independent of license renewal and refurbishment activities.
The primary impact of initial LR or SLR would be the continuation of the receipt of tax revenue
from nuclear plants to local governments and public school districts. The environmental impact
of continued power plant operations on tax revenue in local communities and the expenditure of
tax revenue are not expected to change appreciably. Tax payments during the license renewal
term would be similar to those already being paid. Based on these considerations, the NRC
concludes impacts from continued nuclear plant operations during initial LR and SLR terms and
refurbishment on tax revenue would be the same—SMALL for all nuclear plants. The staff
reviewed information from SEISs (for initial LRs and SLRs) completed since development of the
2013 LR GEIS and identified no new information or situations that would result in different
impacts for this issue for either an initial LR or SLR term. Therefore, tax revenue impacts would
be SMALL for all nuclear plants and a Category 1 issue.

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4.8.1.3

Community Services and Education

Impacts from continued power plant operations and refurbishment activities on public
(community) services and education were evaluated based on the projected number of
“in-migrating” workers with families during the renewal term. Public safety, social services, and
public utility impacts were also considered.
Workforce changes at a nuclear plant can affect the demand for public services in local
communities. Environmental reviews have shown, however, that the number of operations
workers at nuclear plants has not changed significantly because of license renewal, so
demand-related impacts on community services and public utilities are not anticipated. In
addition, refurbishment activities, including steam generator and vessel head replacement, are
being conducted during regularly scheduled refueling and maintenance outages.
Tax payments support a range of community services, including public water, safety, fire
protection, health, social, and educational services. In some communities, tax revenue from
nuclear plants have had a noticeable beneficial impact on the quality and availability of public
services to local residents. Nevertheless, the impact of continued operations and refurbishment
activities on community services and education is SMALL and is not expected to change as a
result of license renewal.
Based on these considerations, the NRC concludes that impacts from continued nuclear plant
operations during initial LR and SLR terms and refurbishment on community services and
education would be the same—SMALL for all nuclear plants. The staff reviewed information
from SEISs (for initial LRs and SLRs) completed since development of the 2013 LR GEIS and
identified no new information or situations that would result in different impacts for this issue for
either an initial LR or SLR term. Therefore, community services and education impacts would be
SMALL for all nuclear plants and a Category 1 issue.
4.8.1.4

Population and Housing

Nuclear power plant-induced population changes, while not an impact in themselves, were
studied as a potential influence on a number of socioeconomic impact issues analyzed in the
LR GEIS. As previously discussed, however, employment levels at nuclear plants are not
expected to change. Therefore, the operational effects of continued operations and
refurbishment activities on population and housing values and availability are not expected to
change from what is already being experienced near nuclear power plants, and no changes in
housing demand is expected during the license renewal term.
The increased number of workers at nuclear power plants during regularly scheduled refueling
and maintenance outages increases the short-term demand for temporary (rental) housing units
near each nuclear plant. However, because of its short duration and repeated nature,
employment-related housing impacts have little or no long-term effect on the price and
availability of rental housing. In addition, refurbishment activities, including steam generator and
vessel head replacement, are being conducted during these refueling and maintenance
outages. Therefore, refurbishment-related housing demand impacts would be similar to what is
already being experienced during regularly scheduled refueling and maintenance outages.
Environmental reviews performed since development of the 2013 LR GEIS have shown that the
number of workers at nuclear plants are not expected to change because of license renewal, so
changes in population and housing availability and value are not anticipated. Based on these

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considerations, the NRC concludes impacts from continued nuclear plant operations
during initial LR and SLR terms and refurbishment on population and housing would be the
same—SMALL for all nuclear plants. The staff reviewed information from SEISs (for initial LRs
and SLRs) completed since development of the 2013 LR GEIS and identified no new
information or situations that would result in different impacts for this issue for either an initial LR
or SLR term. Therefore, population and housing impacts would be SMALL for all nuclear plants
and a Category 1 issue.
4.8.1.5

Transportation

Transportation impacts depend on the size of the workforce, the capacity of the local road
network, traffic patterns, and the availability of alternate commuting routes to and from the
nuclear plant. Because most nuclear power plants have a single access road, there is often
congestion during shift changes.
Transportation impacts are ongoing and have become well-established at all nuclear power
plants. As previously discussed, the number of workers is unlikely to change during the license
renewal term, and environmental reviews have shown little or no need for additional operations
workers. In addition, refurbishment activities, including steam generator and vessel head
replacement, are being conducted during regularly scheduled refueling and maintenance
outages.
The increased number of workers at nuclear power plants during refueling and maintenance
outages have caused short-term increases in traffic volumes on roads in the vicinity of each
plant. However, because of the relative short duration of these outages, increased traffic
volumes have had little or no lasting impact. Therefore, there would be no transportation
impacts during the license renewal term beyond those already being experienced. Based on
these considerations, the NRC concludes transportation impacts from continued nuclear plant
operations during initial LR and SLR terms and refurbishment would be the same—SMALL for
all nuclear plants. The staff reviewed information from SEISs (for initial LRs and SLRs)
completed since development of the 2013 LR GEIS and identified no new information or
situations that would result in different impacts for this issue for either an initial LR or SLR term.
Therefore, transportation impacts would be SMALL for all nuclear plants and a Category 1
issue.

4.9
4.9.1

Human Health
Environmental Consequences of the Proposed Action – Continued Operations
and Refurbishment Activities

Human health conditions at all nuclear power plants and associated transmission lines have
been well established during the current licensing term. Based on past environmental
monitoring data and trends, no significant human health impacts are anticipated during the
license renewal (initial LR or SLR) term that would be different from those occurring during the
current license term. Certain operational changes (such as extended power uprates) that could
potentially affect human health would be evaluated by the NRC in a separate safety and
environmental review.

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4.9.1.1

Environmental Consequences of Normal Operating Conditions

This section provides an evaluation of the impacts of radiological, chemical, microbiological,
EMF, and physical hazards on occupational personnel and members of the public from
continued operation and any refurbishment activities during the initial LR and SLR terms. This
evaluation extends to all United States commercial nuclear power reactors. For safe and reliable
operation of a nuclear power plant, it is necessary to perform routine maintenance on plant
systems and components. Maintenance activities conducted at nuclear power plants include
inspection, surveillance, and repair and/or replacement of material and equipment to maintain
the current licensing basis of the plant and maintain compliance with environmental and public
safety requirements. Certain activities can be performed while the reactor is operating, and
others require that the reactor be shut down. Long-term outages are scheduled for refueling and
for certain types of repairs or maintenance activities, such as the replacement of steam
generators for PWRs.
4.9.1.1.1

Radiological Exposure and Risk

Two environmental issues related to radiological exposure and risk are reviewed here:
(1) radiation exposures to plant workers and (2) radiation exposures to the public, both of
which would result from continued operation and refurbishment activities during the initial LR or
SLR terms.
For the purposes of assessing radiological impacts, impacts are considered to be SMALL if
releases and doses do not exceed the permissible levels in the NRC’s regulations. This
definition of SMALL applies to occupational doses as well as to doses to individual members of
the public. Accidental releases or noncompliance with the standards could conceivably result in
releases that would cause MODERATE or LARGE radiological impacts. Such conditions are
beyond the scope of regulations for controlling normal operations and providing an adequate
level of protection. Environmental consequences and the human health effects of potential
accidents are addressed in Section 4.9.1.2.
Radiation Exposures to Plant Workers
The occupational radiological exposures from current operations at nuclear power plants and
the risk estimates from this radiation exposure are discussed in Section 3.9.
In the 1996 LR GEIS, the impacts from occupational radiological exposure from refurbishment
and continued operations were evaluated separately. To estimate radiation-related impacts on
workers over the license renewal term, occupational radiation exposure was used as the
environmental impact initiator that was quantified. It was assumed that occupational radiation
exposure would change relative to current nuclear plant operations as a result of actions taken
to support license renewal. To evaluate the impacts, two types of license renewal programs
were considered: a “typical” or “mid-stream” license renewal program, and a “conservative” or
“bounding” program (NRC 1996). Each program applied to both PWRs and BWRs. Thus, in all,
four scenarios were considered. It was assumed that activities carried out in support of license
renewal would be performed primarily during selected outages.
Five types of outages were considered: normal refueling outages, 5-year in-service inspection
(ISI) outages, 10-year ISI outages, current-term refurbishment outages, and major
refurbishment outages. The potential actions and activities that would be undertaken during
these outages were identified. All of the rules and regulations, in particular the Maintenance

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Rule (10 CFR 50.65, “Requirements for Monitoring the Effectiveness of Maintenance at Nuclear
Power Plants”), were taken into account in developing typical license renewals or plant-life
extensions (NRC 1996). The occupational exposure for each of the five types of outages was
estimated for all four scenarios (see Table 4.9-1). This analysis is bounding for both the
initial LR and SLR terms as discussed below.
For refurbishment efforts, collective occupational dose estimates for activities during each of the
four current-term refurbishment outages were 11 and 10 person-rem for PWRs and BWRs,
respectively, for the typical case; and 200 and 191 person-rem, respectively, for the
conservative case. Collective occupational dose estimates for the assumed single period of
major refurbishment were 79 and 153 person-rem for PWRs and BWRs, respectively, for the
typical case; and 1,380 and 1,561 person-rem, respectively, for the conservative case. The
individual occupational doses would be well below regulatory limits specified in Table 3.9-1
(i.e., the impact would be SMALL), and the issue was designated as a Category 1 issue.
Table 4.9-1

Additional Collective Occupational Dose (person-rem) for Different Actions
under Typical and Conservative Scenarios during the License Renewal
Term
Typical BWR

Conservative
BWR

Typical PWR

Conservative
PWR

Normal refueling(a)

4

10

3

7

5-yr ISI refueling(b)

71

27

30

35

Outage Type

10-yr ISI

refueling(c)

91

108

51

66

refurbishment(d)

10

191

11

200

Major refurbishment outage(e)

153

1,561

79

1,380

Total all occurrences

457

2,666

261

2,374

Current-term

BWR = boiling water reactor; ISI = in-service inspection; PWR = pressurized water reactor.
(a) 8 occurrences, 2-month duration each.
(b) 2 occurrences, 3-month duration each.
(c) 1 occurrence, 4-month duration for conservative and 3-month duration for typical scenario.
(d) 4 occurrences, 4-month duration for conservative and 3-month duration for typical scenario.
(e) 1 occurrence, 9-month for conservative and 4-month duration for typical scenario.
Sources: Tables 2.8 and 2.11 in the 1996 LR GEIS.

For continued operations during the license renewal term, the NRC observed in the
1996 LR GEIS that the greatest increment to occupational dose over the present dose would
occur during a 10-year ISI refueling. In a typical case, the collective occupational dose would
increase over the present dose by 91 person-rem for a BWR and by 51 person-rem for a PWR.
In a conservative case, the collective occupational dose would increase over the present dose
by 108 person-rem and 66 person-rem, respectively, for BWRs and PWRs. The individual
occupational doses would be well below regulatory limits (i.e., the impact would be SMALL), and
the issue was designated as a Category 1 issue.
For estimating the impacts from continued operation and any refurbishment activities during the
initial LR or SLR term in this LR GEIS revision, the occupational exposure histories for all
commercial nuclear power plants were evaluated for trends.
Throughout the nuclear power industry, modification and upgrade activities have continued at
each operating plant. They have included a broad range of activities in response to NRC

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requirements and industry initiatives, including post-Three Mile Island upgrades, radioactive
waste system modifications, and spent fuel storage upgrades. In addition, several nuclear
power plants have undergone major refurbishment efforts, such as PWR steam generator
replacement and the replacement of coolant recirculation piping in BWRs. These activities
offered a significant potential for occupational exposure. Thus, occupational exposure histories
accumulated to date reflect normal operations plus modifications and additions to existing
systems. This information forms the basis for evaluating the occupational doses that result from
refurbishment and continued operations during initial LR or SLR terms. The data in
Table 3.9-11, Table 3.9-12, Table 3.9-13, and Table 3.9-14 show that there are variations in
occupational dose from year to year, but there is no consistent trend that shows that
occupational doses are increasing over time.
Since 1996, 96 operating reactors at 59 nuclear power plant sites have undergone an
environmental review for license renewal (either for an initial LR and/or SLR). Many nuclear
power plants have already replaced major components like steam generators during their
current license term. Moreover, as part of the license renewal application, the plant licensees
have conducted an aging management review. All of the plant licensees expect to conduct the
activities related to managing impacts from aging during plant operation or normal refueling and
other outages, but they do not plan any outage specifically for the purpose of refurbishment.
License renewal applicants have indicated that the activities conducted during the initial LR or
SLR terms are expected to be within the bounds of normal operations; thus, even the typical
scenario in the 1996 LR GEIS can be considered conservative.
Overall, data presented in tables in Section 3.9 provide ample evidence that occupational doses
at all commercial power plants are far below the occupational dose limit of 5 rem/yr established
by 10 CFR Part 20 and that the continuing efforts to maintain doses at ALARA levels have been
successful.
The wide range of annual collective doses experienced at PWRs and BWRs in the
United States results from a number of factors, such as the reactor design, amount of required
maintenance, and amount of reactor operations and in-plant surveillance. Because these factors
can vary widely and unpredictably, it is difficult to determine in advance specific year-to-year
occupational radiation doses for a particular plant over its operating lifetime. On occasion,
relatively high collective occupational doses (compared to the average annual collective dose)
may be unavoidable, even at plants with radiation protection programs designed to make sure
that occupational doses will be kept to ALARA levels.
Occupational doses have shown a declining trend over the past 10 years and have recently
leveled off. As plants age, there may be slight increases in radioactive inventories, which would
result in slight increases in occupational radiation doses, but no such trend has been observed
in the monitoring data.
Overall, data presented in the tables in Section 3.9 provide evidence that doses to nearly all
radiation workers are far below the worker dose limit established by 10 CFR Part 20 and that
the continuing efforts to maintain doses at ALARA levels have been successful.
Occupational doses from refurbishment activities associated with license renewal and
occupational doses for continued operations during the initial LR or SLR terms are expected to
be similar to the doses during the current operations and bounded by the analysis conducted in
the 1996 LR GEIS. It is estimated that the occupational doses would be much less than the
regulatory dose limits, as described above. Expected occupational radiation exposures meet the

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standard for being of SMALL significance. No mitigation measures beyond those implemented
during the current license term would be warranted, because the ALARA process continues to
be effective in reducing radiation doses.
In the 1996 and 2013 LR GEISs, the NRC concluded that the occupational radiological
exposure impact during license renewal and refurbishment would be SMALL for all plants; it was
therefore designated as a Category 1 issue. The staff reviewed information from SEISs (for
initial LRs and SLRs) completed since development of the 2013 LR GEIS and identified no new
information or situations that would result in different impacts for this issue for either an initial LR
or SLR term. On this basis, the NRC concludes that the impact of continued operations during
initial LR or SLR terms and any refurbishment activities on occupational radiological exposure
during the initial LR or SLR terms would be SMALL for all nuclear plants. This is a Category 1
issue.
Radiation Exposures to the Public
Radiological exposures to the public from current operations at nuclear power plants are
discussed in Section 3.9.1.3. That section includes a discussion of the effluent pathways used in
calculating dose and the radiological monitoring performed at each nuclear plant site to make
sure that unanticipated buildup of radioactivity has not occurred in the environment. The risk
estimates for the public from radiation exposure are discussed in Section 3.9.1.4.
During continued operations following initial LRs or SLRs, small quantities of radioactivity
(fission, corrosion, and activation products) will continue to be released to the environment in a
manner similar to that occurring during present operations (see Section 3.9).
In both the 1996 and 2013 LR GEIS, the NRC evaluated the significance of the estimated public
dose from refurbishment activities, such as steam generator replacement in PWRs and
replacement of recirculation piping in BWRs. Public radiation exposures from gaseous and
liquid effluents produced during refurbishment activities can be evaluated based on effluent data
from the replacement of steam generators and recirculation piping as discussed in the
2013 LR GEIS. During the replacement of steam generators and recirculation piping, releases
of effluents have occurred under controlled conditions and in accordance with ALARA
principles. Similar refurbishment efforts that may occur as part of continued operations following
initial LR or SLR would also take place under controlled conditions and in accordance with
ALARA principles.
The concentration of radioactive materials in soils and sediments increases in the environment
at a rate that depends on the rate of release and the rate of removal. Removal can take place
through radioactive decay or through chemical, biological, or physical processes. For a given
rate of release, the concentrations of longer-lived radionuclides and, consequently, the dose
rates attributable to them would continue to increase if license renewal was granted.
Regulatory Guide 1.109 (NRC 1977) provides guidance for calculating the dose for significant
release pathways. To account for the buildup of radioactive materials, buildup factors are
included in the calculations. The accumulation of radioactive materials in the environment is of
concern not only with regard to license renewal, but also with regard to operation under current
licenses. NRC reporting rules require that pathways that may arise as a result of unique
conditions at a specific nuclear power plant site be considered in licensees’ evaluations of
radiation exposures. If an exposure pathway is likely to contribute significantly to total dose
(10 percent or more to the total dose from all pathways), it must be routinely monitored and

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evaluated. Environmental monitoring programs are in place at all plant sites to provide a backup
to the calculated doses based on effluent release measurements. Because these programs are
ongoing for the duration of the plant’s license, locations where unique situations give rise to
significant pathways that are not detailed in NRC Regulatory Guide 1.109 are to be identified, if
and when they become significant. If such pathways result in doses at a plant exceeding the
design objectives of Appendix I to 10 CFR Part 50, action is required.
The radiation dose to the public from current operations results from gaseous effluent releases
and from liquid effluent releases, as presented in Section 3.9.1.3. At present, for all operating
nuclear plants, doses to the maximally exposed individual (MEI) are much less than the design
objectives of Appendix I to 10 CFR Part 50 (Table 3.9-2). No aspect of future operation has
been identified that would substantially alter this situation.
Maximum individual doses are reported in annual effluent release reports, and if these doses
exceed Appendix I to 10 CFR Part 50 design objectives, the NRC would pursue remedial action.
Thus, these issues are handled on a case-by-case basis. Almost all nuclear power plants have
gone through initial LR, and no aging phenomenon that would increase public radiation doses
has been identified. The operating reactors are not expected to reach regulatory dose limits
more often in the period after initial LR or SLR than they do at present. For these reasons, dose
impacts on MEIs in the public during future operation are judged to be unchanged from those
during present operations. Although dose rates (mrem/yr) are not expected to change during
initial LRs or SLRs, the cumulative dose (total mrem) would increase as a result of 20 to
40 more years of operations. However, it is unlikely that the same person would be exposed to
these doses during the initial LR or SLR term.
One of the pathways considered when calculating the MEI doses is direct radiation from
operating plants. Radiation fields are produced around nuclear plants as a result of radioactivity
within the reactor and its associated components, low-level storage containers, and components
such as steam generators that have been removed from the reactor. Direct radiation from
sources within a light water reactor (LWR) plant is due primarily to nitrogen-16, a radionuclide
produced in the reactor core by neutron activation of oxygen-16 in the water. Because the
primary coolant of an LWR is contained in a heavily shielded area, dose rates in the vicinity of
LWRs are generally undetectable and less than 1 mrem/yr at the site boundary. Some plants
(mostly BWRs) do not have completely shielded secondary systems and may contribute some
measurable offsite dose. However, these sources of direct radiation will be unaffected by
license renewal.
In addition to the regulations within 10 CFR 20.1101 that speak directly to required operation
under ALARA principles, 10 CFR 50.36a imposes conditions on nuclear plant licensees in the
form of technical specifications on effluents from nuclear power reactors. These specifications
are intended to keep releases of radioactive materials to unrestricted areas during operations to
ALARA levels. Appendix I to 10 CFR Part 50 provides numerical guidance on dose-design
objectives and limiting conditions for the operation of LWRs to meet the ALARA requirements.
These regulations will remain in effect during the period of license renewal.
To date, 96 operating reactors at 59 nuclear power plant sites have gone through license
renewal. In all cases, the radiation dose to members of the public from routine operations was
within NRC regulations as presented in Section 3.9.1.3. This information was used to support
the conclusion that the radiation dose to the public will continue at current levels associated with
normal operations and is expected to remain much lower than the applicable standards.

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Offsite doses to the public attributable to refurbishment activities were examined for the MEI.
Because the focus of the analysis is on annual dose, only the results based on the most likely
major refurbishment action were examined (i.e., replacing steam generators in PWRs and
primary recirculation piping in BWRs). For this action, doses to the public were found to be
SMALL. To date, effluents and doses during periods of major refurbishments have not been
observed to differ significantly from those during normal operations. Consequently, gaseous
effluents and liquid discharges occurring during major refurbishment actions are not expected to
result in maximum individual doses exceeding the design objectives of Appendix I to
10 CFR Part 50 (Table 3.9-2) or the allowable EPA standards of 40 CFR Part 190, Subpart B
(Table 3.9-3).
Radiation doses to members of the public from current operations of nuclear power plants have
been examined from a variety of perspectives, and the impacts were found to be well within
design objectives and regulations in each instance. No effect of aging that would significantly
affect the radioactive effluents has been identified. Public doses are expected to remain well
within design objectives and regulations.
Because there is no reason to expect effluents to increase in the period during the initial LR or
SLR term, doses from continued operation are expected to be well within regulatory limits. No
mitigation measures beyond those implemented during the current-term license would be
warranted because current mitigation practices have kept public radiation doses well below
regulatory standards and are expected to continue to do so.
Public radiological exposure impacts during license renewal and refurbishment activities were
considered to be SMALL for all plants and were designated as Category 1 issues in the 1996
and 2013 LR GEISs. The staff reviewed information from SEISs (for initial LRs and SLRs)
completed since development of the 2013 LR GEIS and identified no new information or
situations that would result in different impacts for this issue for either an initial LR or SLR term.
Based on these considerations, the NRC concludes that the impact of continued operations and
refurbishment activities on public radiological exposure during the initial LR and SLR terms
would be SMALL for all nuclear plants. This is a Category 1 issue.
4.9.1.1.2

Nonradiological Hazards

Nonradiological hazards, such as chemical, biological, EMF, and physical hazards are not
unique to nuclear power plants and occur in many types of industrial facilities. However, certain
nonradiological hazards can be enhanced by physical plant elements or characteristics of
nuclear power plants, as discussed in detail in Section 3.9.2.
Chemical Hazards
This renamed issue has been revised from the issue “Human health impact from chemicals” in
the 2013 LR GEIS for the purposes of clarity and to reflect the fact that chemicals can have
environmental effects beyond human health.
A chemical hazard occurs when workers or members of the public are exposed to a
nonradiological hazardous substance by inhalation, skin absorption, or ingestion. Chemical
hazards can have immediate effects (nausea, vomiting, acid burns, asphyxiation—also known
as acute hazards), or the effects might take time to develop (dermatitis, asthma, liver damage,
cancer—also known as chronic hazards). In nuclear power plants, chemical effects could result
from discharges of chlorine or other biocides, small-volume discharges of sanitary and other

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liquid wastes, chemical spills, or heavy metals leached from cooling system piping and
condenser tubing. Impacts of chemical discharges on human health are considered to be
SMALL if the discharges of chemicals to waterbodies are within effluent limitations designed to
protect water quality and if ongoing discharges have not resulted in adverse effects on aquatic
biota. During the initial LR or SLR term, human health impacts from chemicals are expected to
be the same as those experienced during operations under the original license term (see
Section 3.9.2 for more details).
The types of chemical hazards that exist at a nuclear power plant are discussed in
Section 3.9.2.1. Plant workers may encounter hazardous chemicals when the chemistries of the
primary and secondary coolant systems are being adjusted, biocides are being applied to
address the fouling of cooling system components, equipment containing hazardous oils or
other chemicals is being repaired or replaced, solvents are being used for cleaning, or other
equipment is being repaired. Exposures to hazardous chemicals are minimized when plant
workers follow good industrial hygiene practices.
Reviews of the literature and operational monitoring reports and consultations with utilities and
regulatory agencies that were conducted for the 1996 LR GEIS indicated that the effects of the
discharge of chlorine and other biocides on water quality would be of SMALL significance for all
nuclear power plants. Small quantities of biocides are readily dissipated and/or chemically
altered in the waterbody receiving them, so significant cumulative impacts on water quality
would not be expected. Major changes in the operation of the cooling system are not expected
during the license renewal terms, so no change in the effects of biocide discharges on the
quality of the receiving water is anticipated. Major proposed changes in cooling system
operations (e.g., those affecting the plant’s licensing basis and possibly triggering a license
amendment) would require a separate NEPA review, including an examination of human health
effects. In addition, proposed changes in the use of cooling water treatment chemicals would
require review by the plant’s NPDES permit-issuing authority and possible modification of the
existing NPDES permit, including examination of the human health effects of the change. The
effects of biocide discharges could be reduced by increasing the degree to which discharge
water is treated, reducing the concentration of biocides, or treating only a portion of the plant
cooling and service water systems at one time. Discharges of sanitary wastes are regulated by
the plant’s NPDES permit or other regulatory approval, and discharges that do not violate the
permit limits are considered to be of SMALL significance.
The effects of minor chemical discharges and spills at nuclear plants on water quality have been
of SMALL significance and mitigated as needed. Significant cumulative impacts on water quality
would not be expected because the small amounts of chemicals released by these minor
discharges or spills are readily dissipated in the receiving waterbody. While there may be
additional management practices or discharge-control devices that could further reduce the
frequency of accidental spills and off-specification discharges, they are not warranted because
impacts are already SMALL and occur at a low frequency.
Heavy metals (e.g., copper, zinc, and chromium) may be leached from condenser tubing and
other heat exchangers and discharged by power plants as small-volume waste streams or
corrosion products. Although all are found in small quantities in natural waters (and many are
essential micronutrients), concentrations in the power plant discharge are controlled in the
NPDES permit because excessive concentrations of heavy metals can be toxic to aquatic
organisms.

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Nuclear power plants may be required in some instances to submit annual reports on the
environmental releases of listed toxic chemicals manufactured, processed, or otherwise used
that are above identified threshold quantities, depending on State regulations or other specific
circumstances. The disposal of essentially all of the hazardous chemicals used at nuclear power
plants is regulated by Resource Conservation and Recovery Act (RCRA; 42 U.S.C. § 6901
et seq.) or NPDES permits. The NRC requires nuclear power plants to operate in compliance
with all of its environmental permits, thereby minimizing adverse impacts on the environment
and on workers and the public. It is anticipated that all plants will continue to operate in
compliance with all applicable permits, and no mitigation measures beyond those implemented
during the current-term license would be warranted as a result of initial LR or SLR.
The staff reviewed information from SEISs (for initial LRs and SLRs) completed since
development of the 2013 LR GEIS and identified no new information or situations that would
result in different impacts for this issue for either an initial LR or SLR term. Based on these
considerations, the health impact from chemicals on workers and the public, as well as on the
environment, during the initial LR and SLR terms is considered SMALL for all nuclear plants.
This renamed issue is a Category 1 issue.
4.9.1.1.3

Microbiological Hazards

Microbiological hazards occur when workers or members of the public come into contact with
disease-causing microorganisms, also known as etiological agents. Microbiological organisms
of concern for public and occupational health, include enteric pathogens (bacteria that typically
exist in the intestines of animals and humans [e.g., Pseudomonas aeruginosa]), thermophilic
fungi or bacteria (e.g., Legionella spp. and Vibrio spp.), and free-living amoebae (e.g.,
Naegleria fowleri and Acanthamoeba spp.), as well as organisms that produce toxins that affect
human health (e.g., dinoflagellates [Karenia brevis] and blue-green algae). During initial LR and
SLR terms, plant workers and members of the public would be exposed to microbiological
hazards in the same way that they are exposed during operations under the original license
term (see Section 3.9.2.2 for details).
Two environmental issues related to microbiological hazards are reviewed here:
(1) microbiological hazards to plant workers and (2) microbiological hazards to the public (this
issue was modified and renamed from the 2013 LR GEIS to include surface waters accessible
to the public).
Microbiological Hazards to Plant Workers
No change in existing microbiological hazards is expected due to license renewal, for the
reasons discussed in detail in the 2013 LR GEIS. It is considered unlikely that any plants that
have not already experienced occupational microbiological hazards would do so during the
license renewal term or that hazards would increase during that period. The staff reviewed
information from SEISs (for initial LRs and SLRs) completed since development of the
2013 LR GEIS and identified no new information or situations that would result in different
impacts for this issue for either an initial LR or SLR term. It is anticipated that all plants will
continue to employ proven industrial hygiene principles so that adverse occupational health
effects associated with microorganisms during the initial LR and SLR terms will be of SMALL
significance at all sites, and no mitigation measures beyond those implemented during the
current-term license would be warranted. Aside from continued application of accepted
industrial hygiene procedures, no additional mitigation measures are expected to be warranted
as a result of license renewal. This is a Category 1 issue.

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Microbiological Hazards to the Public
This renamed issue is an expansion of the issue “Microbiological hazards to the public (plants
with cooling ponds or canals or cooling towers that discharge to a river)” in the 2013 LR GEIS,
because this issue is a concern wherever receiving waters are accessible to the public.
Specifically, members of the public could be exposed to microorganisms in thermal effluents at
nuclear power plants that use cooling ponds, lakes, canals, or that discharge to publicly
accessible surface waters. As discussed in Section 3.9.2.2, the SEISs published since 2013
were reviewed to determine the level of thermophilic microbiological organism enhancement in
waters accessible to the public. Although reviews to date note that health departments did not
have concerns related to microbiological hazards, changes in microbial populations and in the
public use of waterbodies might occur after the operating license is issued and the application
for initial LR or SLR is filed. Other factors could also change, including the average temperature
of the water, which could result from climate change affecting water levels and air temperature.
Finally, the long-term presence of a power plant might change the natural dynamics of harmful
microorganisms within a body of water. Therefore, the magnitude of the potential public health
impacts associated with thermal enhancement of thermophilic organisms during the initial LR
and SLR terms could be SMALL, MODERATE, or LARGE, depending on plant-specific
conditions. This renamed issue is a Category 2 issue.
4.9.1.1.4

Electromagnetic Fields (EMFs)

This renamed issue is a clarification of the issue “Chronic effects of electromagnetic fields
(EMFs)” in the 2013 LR GEIS because this issue concerns effects beyond just those that might
be chronic in nature. Nuclear power plants use power transmission systems that consist of
switching stations (or substations) located on the plant site and transmission lines located
primarily offsite that connect the power plant to the regional electric grid. Electric fields and
magnetic fields, collectively referred to as EMFs, are produced by any electrical equipment,
including operating transmission lines. During the initial LR or SLR, plant workers and members
of the public who live, work, or pass near an associated operating transmission line may be
exposed to EMFs in the same way that they are exposed during the current license term (see
Section 3.9.2.3 for more detail). The issue was further evaluated in the 2013 LR GEIS by
reviewing the relevant literature.
As in the 2013 LR GEIS, the scope of the evaluation in this LR GEIS is limited to the
transmission lines that connect the plant to the switchyard where electricity is fed into the
regional power distribution system (encompassing those lines that connect the plant to the first
substation of the regional electric power grid) and power lines that feed the plant from the grid
(see Section 3.1.7).
The potential health effects from EMF exposure have been the subject of published studies; a
discussion of some of these studies was presented in the 2013 LR GEIS in Section 4.9.1.1.4
and are incorporated here by reference. A review of the biological and physical studies of
60 hertz (Hz) EMFs completed during preparation of the 2013 LR GEIS did not find any
consistent evidence that would link harmful effects with field exposures. EMFs are unlike other
agents that have a toxic effect (e.g., toxic chemicals and ionizing radiation) in that dramatic
acute effects cannot be forced, and longer-term effects, if real, are subtle. Nonetheless, a wide
range of biological responses have been reported to be affected by EMFs.
Even if clear adverse effects were apparent in the epidemiology literature or with some
biological assay, considerable additional work would be required to determine how and what to

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mitigate because evidence suggests that the severity of some EMF biological effects may not
correlate directly with exposure. Furthermore, there may be a subtle relationship between the
intensity of the local geomagnetic field and the appearance of effects for some intensities of
60 Hz fields. This complicating evidence points to the fact that, while much experimental and
epidemiological evidence has been accrued, understanding of this issue continues to evolve.
For this renamed issue, because of inconclusive scientific evidence, the health effects of EMFs
during the initial LR and SLR terms are considered UNCERTAIN, and currently, no generic
impact level can be assigned. The NRC will continue to monitor the research initiatives—both
those within the national EMF program and others internationally—to evaluate the potential
carcinogenicity of EMFs as well as other progress in the EMF study disciplines. If the NRC finds
that the appropriate Federal health agencies have reached a consensus on the potential human
health effects of exposure to EMF, the NRC will revise the LR GEIS to include the new
information and describe effective mitigating measures.
4.9.1.1.5

Physical Hazards

Two additional human health issues are addressed in this section: (1) physical occupational
hazards and (2) electric shock hazards, both previously considered in the 2013 LR GEIS.
Nuclear power plants are industrial facilities that have many of the typical occupational hazards
found at any other electric power generation facility. Power plant and maintenance workers
could be working under potentially hazardous physical conditions (e.g., excessive heat, cold,
and hazardous locations), including those experienced when conducting electrical work, power
line maintenance, and repair work. The issue of physical occupational hazards is generic to all
nuclear power plants.
Transmission lines are needed to transfer energy from the nuclear power plant to consumers.
The workers and general public at or around the nuclear power plants and along the
transmission lines are potentially exposed to acute electrical shock from these lines. The issue
of electrical shock is generic to all nuclear power plants. As described in Section 3.1.7, in-scope
transmission lines include only those lines that would not continue to operate if a plant’s license
was not renewed. Using this criterion, in-scope transmission lines are those lines that connect
the plant to the first substation of the regional electric grid. This substation is frequently, but not
always, located on the nuclear plant property.
During the initial LR or SLR terms, human health impacts from physical occupational hazards
and acute shock hazards would be the same as those from operations during the original
license term (see Section 3.9.2.4 for more detail).
Physical Occupational Hazards
The types of physical hazards that exist at a nuclear power plant are discussed in
Section 3.9.2.4. The issue of occupational hazards is evaluated by comparing the rate of fatal
injuries and nonfatal occupational injuries and illnesses in the utility sector with the rate in all
industries combined. Occupational hazards can be minimized when workers adhere to safety
standards and use appropriate personal protective equipment; however, fatalities and injuries
from accidents can still occur. Data for occupational injuries from the U.S. Bureau of Labor
Statistics are discussed in detail in Section 3.9.2.4. The staff reviewed information from SEISs
(for initial LRs and SLRs) completed since development of the 2013 LR GEIS and identified no
new information or situations that would result in different impacts for this issue for either an
initial LR or SLR term. It is expected that during the initial LR or SLR term, workers would

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continue to adhere to safety standards and use protective equipment, so adverse occupational
impacts during the initial LR and SLR terms would be of SMALL significance at all sites, and no
mitigation measures beyond those implemented during the current license term would be
warranted. This is a Category 1 issue.
Electric Shock Hazards
In-scope transmission lines are those lines that connect the plant to the first substation of the
regional electric grid. This substation is frequently, but not always, located on the plant property.
The greatest hazard from a transmission line is direct contact with the conductors. Tower
designs preclude direct access to the conductors. However, electrical contact can be made
without physical contact between a grounded object and the conductor, as discussed in
Section 3.9.2.4.1. A person who contacts such an object could receive a shock and experience
a painful sensation at the point of contact. The intensity of the shock would depend on the EMF
strength, size of the object, and how well the object and person were insulated from ground.
The staff reviewed information from SEISs (for initial LRs and SLRs) completed since
development of the 2013 LR GEIS. Design criteria for nuclear power plants that limit hazards
from steady-state currents are based on the National Electrical Safety Code (NESC), adherence
to which requires that power companies design transmission lines so that the short-circuit
current to ground produced from the largest anticipated vehicle or object is limited to less than
5 mA (IEEE SA 2017, 2023). The electrical shock issue, which is generic to all types of electrical
generating stations, including nuclear plants, is of SMALL significance for transmission lines that
are operated in adherence with the NESC. Without a review of the conformance of each nuclear
plant’s transmission lines within this scope of review with NESC criteria, it is not possible to
determine the significance of the electrical shock potential generically during the initial LR or
SLR term; it could be SMALL, MODERATE, or LARGE. The hazard of electric shock is a
Category 2 issue.
4.9.1.2
4.9.1.2.1

Environmental Consequences of Postulated Accidents
Design-Basis Accidents and Severe Accidents

Chapter 5 of the 1996 LR GEIS assessed the impacts of postulated accidents at nuclear power
plants on the environment. The postulated accidents included design-basis accidents and
severe accidents (e.g., those with reactor core damage). The impacts considered included:
• dose and health effects of accidents (5.3.3.2 through 5.3.3.4 of the 1996 LR GEIS)
• economic impacts of accidents (5.3.3.5 of the 1996 LR GEIS)
• impact of uncertainties on results (5.3.4 of the 1996 LR GEIS)
The estimated impacts were based upon the analysis of severe accidents at 28 nuclear power
plants,16 as reported in the environmental impact statements (EISs) and/or final environmental
statements prepared for each of the 28 plants in support of their operating licenses. With few
exceptions, the severe accident analyses were limited to consideration of reactor accidents
caused by internal events. The 1996 LR GEIS addressed the impacts from external events
16

The 28 sites are listed in Table 5.1 of the 1996 LR GEIS. There are a total of 44 units included in this
list, but 4 of the units never operated (Grand Gulf 2, Harris 2, Perry 2, and Seabrook 2). For the purposes
of this document, this list will be referred to as containing 28 nuclear power plants, but when mean values
are calculated for this subset of nuclear power plants, the 40 units that operated are considered.

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qualitatively. The severe accident analysis for the 28 plants was extended to the remainder of
plants whose EISs did not consider severe accidents (because such analysis was not required
at the time the other plants’ EISs were prepared). The estimates of environmental impact
contained in the 1996 LR GEIS used 95th percentile upper confidence bound estimates
whenever available. This provides conservatism to cover uncertainties, as described in
Section 5.3.3.2.2 of the 1996 LR GEIS. The 1996 LR GEIS concluded that the
probability-weighted consequences and impacts were SMALL compared to other risks to which
the populations surrounding nuclear power plants are routinely exposed.
Appendix E of this document provides an update on postulated accident risk. Because the
NRC’s understanding of accident risk has evolved since the issuance of the 1996 LR GEIS and
extends beyond issuance of the 2013 LR GEIS, Appendix E assesses more recent information
about postulated accidents that might have had the potential to alter the conclusions in
Chapter 5 of the 1996 LR GEIS. This update considers how these developments would affect
the conclusions in the original LR GEIS and provides comparative data where appropriate.
The different sources of new information can be generally categorized by their effect of either
decreasing, not affecting, or increasing the best-estimate environmental impacts associated with
postulated severe accidents. The areas where a decrease in best-estimate impacts would be
expected are:
• new internal events information (decreases)
• new source term information (significant decreases)
Areas likely leading to either a small change or no change include:
• use of Biological Effects of Ionizing Radiation VII (BEIR-VII) risk coefficients
Lastly, the areas leading to an increase in best-estimate impacts would consist of:
• consideration of external events (comparable to internal event impacts)
• power uprates (small increase)
• higher fuel burnup (small increases)
• low power and reactor shutdown events (could be comparable to at-power event impacts)
• new SFP accidents (lower risk than that from full power reactor operations, but is
conservatively considered to be comparable to that from full power reactor operations)
Given the difficulty in conducting a rigorous aggregation of these results (due to the differences
in the information sources used and in the impact metrics evaluated), a fairly simple approach is
taken. The latter group contains two areas (power uprates and higher fuel burnup) where the
increase in environmental impact (probability-weighted consequences) would cumulatively be
less than 50 percent. For one area (SFP accidents), the increase in environmental impact would
be less than that from power reactor operations, but is conservatively considered to be
comparable to that from full power reactor operations. The increase in environmental impact
from consideration of low power and shutdown events is comparable to that from at-power
operations, but is conservatively assumed to be up to a factor of 2 to 3 higher. The final factor,
external events, was not assessed separately, but as an integrated assessment considering all
hazards. The net increase from the four factors is conservatively an increase of up to a factor of
4 to 5, or 400 to 500 percent.

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The reduction in environmental impact associated with the new source term information is
dramatic. The early fatality risk is orders-of-magnitude less than the NRC safety goal, and the
latent cancer fatality risk is well below the NRC safety goal. However, because the
state-of-the-art reactor consequence analysis (SOARCA) (NUREG-1935; NRC 2012i) did not
evaluate the risk of all accident scenarios, this reduction in environmental impact is not credited
in this assessment. The other factor that has resulted in a decrease in environmental impact is
the risk of at-power severe reactor accidents due to internal events. The internal events core
damage frequency has decreased, on average, by a factor of 4 to 6. However, the reduction in
environmental impact is substantial, ranging from a factor of 2 to 600 and, on average, is about
a factor of 30 lower when compared to the expected value of the population dose risk reported
in the 1996 LR GEIS. Because the 1996 LR GEIS did not explicitly consider the contribution
from external events in the estimate of the environmental impacts from severe accidents, an
explicit consideration would be expected to increase the estimated environmental impacts.
However, because the estimates of the probability-weighted consequences reported in the
1996 LR GEIS were intentionally developed to be very conservative, an explicit consideration of
the risk from all hazards in this LR GEIS has shown that the probability-weighted dose
consequences are bounded by the 1996 LR GEIS estimates. Specifically, the net result when all
hazards are considered is that the All Hazards core damage frequency, on average, is
comparable to that assumed for just internal events in the 1996 LR GEIS. Furthermore, the
reduction in All Hazards population dose risk, or probability-weighted dose consequence,
ranges from a factor of 3 to over 1,000 and is, on average, about a factor of 120 (or
12,000 percent) less than the corresponding predicted 95 percent upper confidence bound
values estimated in the 1996 LR GEIS.
The net effect of a maximum increase of accident risk on the order of 400 to 500 percent and a
decrease of more than 10,000 percent would be a substantial reduction in estimated impacts
(compared to the 1996 LR GEIS assessment). This result demonstrates the substantial level of
conservatism incorporated in the upper bound estimates used in the 1996 LR GEIS, which
supported the conclusion that the probability-weighted consequences of atmospheric releases,
fallout onto open bodies of water, releases to ground water, and societal and economic impacts
of severe accidents are of small significance for all plants.
With respect to uncertainties, the 1996 LR GEIS contained an assessment of uncertainties in
the information used to estimate the environmental impacts. Section 5.3.5 of the 1996 LR GEIS
discusses the uncertainties and concludes that they could cause the impacts to vary anywhere
from a factor of 10 to a factor of 1,000. This range of uncertainties bounds the uncertainties
discussed in Section E.3.9 of Appendix E of this revised LR GEIS, as well as the uncertainties
brought in by the other sources of new information, by one or more orders of magnitude.
Section E.3.9 of this LR GEIS notes that more recent detailed quantitative analyses indicate that
the 95th percentile bounds of consequence uncertainty are likely to be about a factor of 10 or
less compared to point-estimates or compared to other central-tendency estimates.
Based on the analysis presented in Appendix E, the staff concludes that the reduction in
environmental impacts from the use of new information (since the 1996 and 2013 LR GEIS
analyses) outweighs any increases resulting from this same information for initial LR or SLR. In
part, the staff reviewed information from SEISs (for initial LRs and SLRs) completed since
development of the 2013 LR GEIS and identified no new information or situations that would
result in different impacts for this issue for either an initial LR or SLR term. As a result, the
findings in the 1996 LR GEIS and 2013 LR GEIS remain valid. Therefore, the environmental
impacts of design-basis accidents are SMALL for all plants during the initial LR and SLR terms
and the issue is Category 1.

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In the 2013 LR GEIS, the issue of severe accidents remained a Category 2 issue to the extent
that only the alternatives to mitigate severe accidents must be considered for all nuclear power
plants where the licensee had not previously performed a severe accident mitigation
alternatives analysis for the plant. This LR GEIS update provides a technical basis for
reclassifying the issue of “Severe accidents” as Category 1.
Consistent with the NRC’s approach to severe accident mitigation in the 1996 LR GEIS and the
2013 LR GEIS, alternatives to mitigate severe accidents still must be considered for all plants
that have not considered such alternatives and would be the functional equivalent of a
Category 2 issue requiring plant-specific analysis; however, as discussed further in Appendix E,
the plants that have already had a severe accident mitigation alternatives (SAMA) analysis
considered by the NRC as part of an EIS, supplement to an EIS, or environmental assessment,
need not undergo an additional severe accident mitigation alternatives analysis for license
renewal. Appendix E, Table E.5-1 provides a summary of the NRC staff’s findings with respect
to these issues. Based on current industry plans, the NRC expects very few, if any, license
renewal applications for a plant that has not previously considered severe accidents under
NEPA. Consequently, severe accidents are most accurately categorized as a Category 1 issue
because it will be resolved generically for the vast majority of, if not all, applicants. The totality of
the studies and regulatory actions discussed in Appendix E (Section E.4) reinforces the
Commission’s decision to not require applicants to perform a SAMA analysis in an initial LR or
SLR application if the NRC has previously completed a SAMA or similar analysis for their
nuclear plant in a NEPA document. As discussed above, the impacts of all new information in
this update do not contribute sufficiently to the environmental impacts of severe accidents to
undermine the Commission’s determination not to require further SAMA analysis because the
likelihood of finding cost-effective significant plant improvements is small.
In part, the staff reviewed information from SEISs (for initial LRs and SLRs) completed since
development of the 2013 LR GEIS and identified no new information or situations that would
result in different impacts for this issue for either an initial LR or SLR term. Based on these
considerations, the NRC staff concludes that the probability-weighted consequences of severe
accidents during the initial LR and SLR terms are SMALL for all operating nuclear power plants.
As a result, the issue of “Severe accidents” is revised from Category 2, as evaluated in the
2013 LR GEIS (NRC 2013a), to Category 1.

4.10 Environmental Justice
4.10.1

Environmental Consequences of the Proposed Action – Continued Operations
and Refurbishment Activities

As explained in Chapter 3, Executive Order 12898, “Federal Actions to Address Environmental
Justice in Minority Populations and Low-Income Populations” (1994) (59 FR 7629), directs each
Federal agency to identify and address, as appropriate, “disproportionately high and adverse
human health or environmental effects of its programs, policies, and activities on minority
populations and low-income populations.” Although independent agencies, like the NRC, were
only requested, rather than directed, to comply with Executive Order 12898, the NRC Chairman,
in a March 1994 letter to the President, committed the NRC to endeavoring to carry out its
measures “ … as part of NRC’s efforts to comply with the requirements of NEPA” (NRC 1994).

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4.10.1.1

Impacts on Minority Populations, Low-Income Populations, and Indian Tribes

The environmental justice impact analysis determines whether human health or environmental
effects from continued reactor operations and refurbishment activities at a nuclear power plant
would disproportionately affect a minority population, low-income population, or Indian Tribe,
and whether these effects may be high and adverse. Adverse health effects are measured in
terms of the risk and rate of fatal or nonfatal exposure to an environmental hazard.
Disproportionately high and adverse human health effects occur when the risk or rate of
exposure for a minority population, low-income population, or Indian Tribe to an environmental
hazard is significant and exceeds the risk or rate to the general population or other comparison
group.
Disproportionately high and adverse environmental effects occur when an impact on the natural
or physical environment significantly and adversely affects a minority population, low-income
population, or Indian Tribe and exceeds those on the general population or other comparison
group. Such effects may include ecological, cultural, socioeconomic, or social impacts. These
environmental effects are discussed in this chapter for each of these and other resource areas.
For example, increased demand for rental housing during the construction of a new power plant
for one of the energy replacement alternatives could disproportionately affect low-income
populations.
The NRC’s environmental justice impact analysis (1) identifies minority populations, low-income
populations, and Indian Tribes that could be affected by continued reactor operations during the
license renewal term and refurbishment activities at a nuclear power plant; (2) determines
whether there would be any human health or environmental effects on these populations; and
(3) determines whether these effects may be disproportionately high and adverse. The NRC
strives to engage with representatives of affected environmental justice communities and Tribal
Nations to establish long-term relationships and identify license renewal-related concerns and
issues to be addressed in the NEPA review. Minority and low-income populations, Indian Tribes,
and environmental justice issues are different at each nuclear power plant site.
Continued reactor operations during the license renewal term and refurbishment activities at a
nuclear power plant could affect land, air, water, and ecological resources, which could result in
human health or environmental effects. Consequently, minority and low-income populations and
Indian Tribes could be disproportionately affected. The NRC’s environmental justice impact
analysis must therefore determine whether continued reactor operations during the license
renewal term and refurbishment activities at a nuclear power plant would result in
disproportionately high and adverse human health or environmental effects on a minority
population, low-income population, or Indian Tribe.
Section 4-4 of Executive Order 12898 also directs Federal agencies, whenever practical and
appropriate, to collect and analyze information about the consumption patterns of populations
that rely principally on fish and wildlife for subsistence and to communicate the risks of these
consumption patterns to the public. Consumption patterns (e.g., subsistence agriculture,
hunting, and fishing) and certain resource dependencies often reflect the traditional or cultural
practices of minority populations, low-income populations, and Indian Tribes. Consequently, the
NRC considers the means by which these populations could be disproportionately affected by
examining potential human health and environmental effects from continued reactor operations
and refurbishment activities at nuclear power plants. In assessing the human health effects of
license renewal, the NRC examines radiological risk from consumption of fish, wildlife, and local
produce; exposure to radioactive material in water, soils, and vegetation; and the inhalation of

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airborne radioactive material during nuclear power plant operation. To assess the effect of
nuclear reactor operations, licensees are required to collect samples from the environment, as
part of their REMP. These samples are then analyzed for radioactivity to assess the impact from
nuclear power plant operations.
A nuclear plant effect may be indicated if the radiation level detected in a sample is higher than
the background level. Two types of samples are collected. The first type—control samples—are
collected from areas of the environment beyond or outside the influence of the nuclear power
plant. Control samples are used to determine normal background radiation levels. The second
type—indicator samples—are collected from the environment near the nuclear power plant
where any radioactivity would be at its highest concentration. Indicator samples are then
compared to control samples to determine the contribution of nuclear power plant operation to
radiation or radioactivity levels in the environment. A nuclear plant effect is indicated if
radioactivity levels in an indicator sample exceed the background radiation levels in the control
sample.
Moreover, as noted in the Commission’s “Policy Statement on the Treatment of Environmental
Justice Matters in NRC Regulatory and Licensing Actions” (69 FR 52040), the NRC recognizes
that environmental justice issues “differ from site to site and, thus, do not lend themselves to
generic resolutions. Consequently, [environmental justice], as well as other socioeconomic
issues, are normally considered in site-specific EISs.” For this reason, environmental justice is a
Category 2 issue, and the NRC makes its license renewal impact determination in nuclear plantspecific SEISs.
Based on these considerations, the NRC concludes environmental justice impacts during initial
LR and SLR terms and refurbishment are unique to each nuclear power plant. In addition, the
NRC identified no new information or situations regarding initial LR or SLR that would result in
different conclusions from the 2013 LR GEIS. Therefore, the issue of environmental justice
impacts from license renewal cannot be determined generically, and it is a Category 2 issue.

4.11 Waste Management and Pollution Prevention
4.11.1

Environmental Consequences of the Proposed Action – Continued Operations
and Refurbishment Activities

The effects of license renewal including operations and refurbishment on waste management
are presented in this section. Baseline conditions at operating reactors are discussed in
Section 3.11. License renewal is expected to result in a continuation of these conditions for an
extended period commensurate with the license renewal term (initial LR or SLR). Accumulated
quantities of waste material needing long-term storage or disposal are expected to increase at a
rate proportional to the length of operation.
The impacts associated with onsite waste management activities during a license renewal term
(initial LR and SLR) at nuclear power plants are addressed in other sections of Chapter 4 under
various resource discussions. These activities include waste collection, treatment, packaging,
and loading onto conveyance vehicles for shipment offsite. These activities are considered to be
part of the normal operations at a plant site. For example, the annual radioactive effluent
release reports issued by plant licensees include a summary of radioactive effluent releases
from all the facilities on the plant site, including the waste management and storage facilities.
The same reports also provide data on the volume and radioactivity content of solid radioactive
waste shipped offsite for processing and disposal. Similarly, the REMP conducted by nuclear

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power plant licensees measures the direct radiation as well as environmental concentrations of
all radionuclides originating at the site as well as background radiation. The impact from the
transportation of wastes from the reactor to a third-party waste treatment center or directly to a
disposal site is addressed generically in Table S-4 in 10 CFR 51.52 (see Section 4.14.1.4).
The issues addressed in this section regarding waste management during the license renewal
term (as evaluated in the 2013 LR GEIS (NRC 2013a)) include:
• low-level radioactive waste (LLW) storage and disposal
• onsite storage of spent nuclear fuel
• offsite radiological impacts of spent nuclear fuel and high-level waste disposal
• mixed waste storage and disposal
• nonradiological waste storage and disposal
These five issues relate to waste management at all nuclear fuel cycle facilities, including
nuclear power plants. Four other issues, which pertain specifically to aspects of the uranium fuel
cycle other than the nuclear power plants themselves, are addressed in Section 4.14.1.5. These
fuel cycle facilities include uranium mining and milling, uranium hexafluoride (UF6) production,
isotopic enrichment, fuel fabrication, fuel reprocessing, and disposal facilities.
4.11.1.1

Low-Level Waste Storage and Disposal

Section 3.11.1.1 provides a detailed discussion of the quantities and characteristics of LLW that
are normally generated at nuclear plants under routine operating conditions. As stated in the
introduction to Section 4.11.1, these baseline conditions are expected to continue during the
license renewal (initial LR and SLR) terms.
The NRC requires that all licensees implement measures to minimize, to the extent practicable,
the generation of radioactive waste (10 CFR 20.1406). Licensees may consider construction of
additional radiological storage facilities on their plant sites and/or enter into an agreement with a
third-party contractor to process, store, own, and ultimately dispose of LLW from the reactor
sites. The environmental impacts, if these options are chosen, would be assessed at that time.
Most of the LLW generated at reactor sites continues to be shipped offsite for disposal, either
immediately after generation or after a brief storage period onsite. This trend is expected to
continue during the license renewal (initial LR and SLR) term. Operating disposal facilities for
radioactive waste are discussed in Section 3.11.1.1. In addition, the reactor sites have the
option to store their Class B and C (and Class A as appropriate) wastes onsite. Such activities
are conducted in accordance with NRC regulations and any applicable State or local
requirements.
The NRC believes that the comprehensive regulatory controls that are in place and the low
public doses being achieved at reactors ensure that the radiological impacts on the environment
from LLW storage and disposal will remain SMALL during the term of a renewed license
(initial LR and SLR). The maximum additional onsite land that may be required for LLW storage
during the term of a renewed license and associated impacts would be SMALL. The radiological
and nonradiological environmental impacts of long-term disposal of LLW from any individual
plant at licensed sites are SMALL. In addition, the NRC concludes that the available information

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supports a conclusion that sufficient LLW disposal capacity will be made available when needed
for facilities to be decommissioned consistent with NRC decommissioning requirements.
Based on the above considerations and the information presented in Section 3.11.1.1, the
existing radiological waste infrastructure and management program could support the additional
radiological wastes generated by the operation of the nuclear power plant through the renewal
licensing term. The impact of LLW storage and disposal during the renewal term (initial LR and
SLR) is considered SMALL for all sites and is designated as a Category 1 issue. The staff
reviewed information from SEISs (for initial LRs and SLRs) completed since development of the
2013 LR GEIS and identified no new information or situations that would result in different
impacts for this issue for either an initial LR or SLR term. Therefore, the environmental impacts
associated with LLW storage and disposal during the initial LR and SLR terms would be SMALL
for all nuclear plants. This issue is Category 1.
In addition to being generated at the reactor sites, LLW is also generated from the rest of the
uranium fuel cycle as part of the front-end operations during the mining and milling of uranium
ores and during the steps leading up to the manufacture of new fuel. If the recycling option is
made available and the decision is made to reprocess the spent nuclear fuel in the
United States, the reprocessing operations would also generate LLW. The impacts associated
with management of LLW from these other fuel cycle operations are addressed in Table S-3 in
10 CFR 51.51 (see Section 4.14.1.2).
4.11.1.2

Onsite Storage of Spent Nuclear Fuel

The scope of this LR GEIS with regard to the management and ultimate disposition of spent
nuclear fuel is limited to the findings codified in the September 19, 2014 Continued Storage of
Spent Nuclear Fuel, Final Rule (79 FR 56238) and associated NUREG-2157, Generic
Environmental Impact Statement for Continued Storage of Spent Nuclear Fuel (Continued
Storage GEIS; NRC 2014c) (79 FR 56263). (See Section 1.7.2 of this LR GEIS for the history of
this document and associated rulemaking.) During the license renewal term, which corresponds
to part of the licensed life for operation of a reactor described in NUREG-2157, the expected
increase in the volume of spent fuel from an additional 20 years of operation (either during
initial LR or SLR) can be safely accommodated onsite during the license renewal term with
small environmental impacts through dry or pool storage at all plants. For the period after the
licensed life for reactor operations, the impacts of onsite storage of spent nuclear fuel during the
continued storage period are discussed in NUREG-2157 and are as stated in § 51.23(b). As
defined in NUREG-2157 and clarified in the Continued Storage Final Rule (79 FR 56238,
page 56263), the licensed life for operation of a reactor assumes an original licensed life of
40 years and up to two 20-year license extensions for each reactor, for a total of up to 80 years
of operation.
As discussed in Section 3.11.1.2, spent fuel is currently stored at reactor sites either in SFPs or
in independent spent fuel storage installations (ISFSIs). This onsite storage of spent fuel and
high-level waste (HLW) is expected to continue into the foreseeable future.
As previously considered in the 2013 LR GEIS, and further supported by analyses presented in
the 2014 Continued Storage GEIS (NRC 2014c) for the short-term storage timeframe for spent
nuclear fuel, current and potential environmental impacts from spent fuel storage at the current
reactor sites have been studied extensively, are well understood, and the environmental
impacts were found to be SMALL. The issue of onsite storage during the license renewal term
was designated a Category 1 issue in the 2013 LR GEIS with an impact of SMALL. The staff

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reviewed information from SEISs (for initial LRs and SLRs) completed since development of the
2013 LR GEIS and identified no new information or situations that would result in different
impacts for this issue for either an initial LR or SLR term. Therefore, the environmental impacts
associated with the storage of spent nuclear fuel during the initial LR and SLR terms would be
SMALL for all nuclear plants. For the period after the licensed life for reactor operations, the
impacts of onsite storage of spent nuclear fuel during the continued storage period are
discussed in NUREG-2157 and are stated in § 51.23(b) (NRC 2014c). The NRC staff identified
no new information or situations that would result in different impacts during the continued
storage period at any nuclear plant site. This issue is Category 1.
4.11.1.3

Offsite Radiological Impacts of Spent Nuclear Fuel and High-Level Waste Disposal

The scope of this LR GEIS with regard to the management and ultimate disposition of spent
nuclear fuel is limited to the findings codified in the September 19, 2014 Continued Storage of
Spent Nuclear Fuel, Final Rule (79 FR 56238) and associated NUREG-2157 (79 FR 56263), the
Continued Storage GEIS (NRC 2014c).
The ultimate disposal of spent fuel in a potential future geologic repository is a separate and
independent licensing action that is outside the regulatory scope of license renewal. The
following discussion provides relevant information with respect to developments pertaining to
the consideration of an ultimate repository site for the disposal of spent fuel.
At the time the 1996 LR GEIS was issued, there were no established regulatory limits for offsite
releases of radionuclides from the ultimate disposal of spent fuel and HLW, because a
candidate repository site had not been established. It was assumed that for such a site, limits
would eventually be developed along the lines of those given in the 1995 National Academy of
Sciences report, Technical Bases for Yucca Mountain Standards (National Research Council
1995).
On February 15, 2002, based on a recommendation by the Secretary of Energy, the President
recommended the Yucca Mountain site for the development of a repository for the geologic
disposal of spent fuel and HLW. Congress approved this recommendation on July 9, 2002, in
Joint Resolution 87, which designated Yucca Mountain as the repository for spent fuel. On
July 23, 2002, the President signed Joint Resolution 87 into law. Public Law 107-200, 116
Statutes at Large 735, 42 U.S.C. 10135 (note) (H.J. Res. 87), designates Yucca Mountain as
the site for the development of the repository for spent fuel.
Subsequently, the EPA developed Yucca Mountain-specific repository release standards, which
were also adopted by the NRC in 10 CFR Part 63. These standards:
• Establish a dose limit of 15 millirem (0.15 millisievert) per year for the first 10,000 years after
disposal.
• Establish a dose limit of 100 millirem (1.0 millisievert) exposure per year between
10,000 years and 1 million years.
• Require the DOE to consider the effects of climate change, earthquakes, volcanoes, and
corrosion of the waste packages to safely contain the waste during the 1 million-year period.
• Establish a radiological protection standard consistent with the recommendations of the
National Academy of Sciences for this facility at the time of peak dose up to 1 million years
after disposal.

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On June 3, 2008, the DOE submitted a license application to the NRC, seeking authorization to
construct a geologic repository for the disposal of spent fuel and HLW at Yucca Mountain,
Nevada (NRC 2020l). As part of the site characterization and recommendation process for the
proposed geologic repository at Yucca Mountain, the DOE was required by the Nuclear Waste
Policy Act of 1982, 42 U.S.C. 10101 et seq., to prepare an EIS. In accordance with the Nuclear
Waste Policy Act (42 U.S.C. 10134(f)(4)), the NRC was required to adopt DOE’s EIS, to “the
extent practicable,” as part of any possible NRC construction authorization decision. DOE
submitted the following NEPA documents along with its application, which include analyses that
address radiological impacts to workers and the public:
• Final Environmental Impact Statement for a Geologic Repository for the Disposal of Spent
Nuclear Fuel and High-Level Radioactive Waste at Yucca Mountain, Nye County, Nevada
(FEIS) (DOE 2002).
• Final Supplemental Environmental Impact Statement for a Geologic Repository for the
Disposal of Spent Nuclear Fuel and High-Level Radioactive Waste at Yucca Mountain,
Nye County, Nevada (Repository SEIS) (DOE 2008).
The NRC formally accepted for docketing DOE’s license application for Yucca Mountain,
Nevada, on September 8, 2008 (73 FR 53284). In its acceptance, the NRC staff also
recommended that the Commission adopt, with further supplementation, the EIS and
supplements prepared by DOE. With respect to radiological impacts, DOE’s FEIS and
Repository SEIS indicate that the disposal of spent fuel and HLW would be SMALL with
exposures well below regulatory limits. However, on March 3, 2010, the DOE filed a motion with
the Atomic Safety and Licensing Board (Board) seeking permission to withdraw its application
for authorization to construct a HLW geologic repository at Yucca Mountain, Nevada. The Board
denied that request on June 29, 2010, in LBP-10-11 (NRC 2010d), whereupon the parties
involved in the preceding filed petitions asking the Commission to uphold or reverse this
decision.
On September 9, 2011, the Commission issued a Memorandum and Order, CLI-11-07, stating
that it found itself evenly divided on whether to take the affirmative action of overturning or
upholding the Board’s June 29, 2010, decision (NRC 2011c). Exercising its inherent supervisory
authority, the Commission directed the Board to complete all necessary and appropriate case
management activities by September 30, 2011. On September 30, 2011, the Board issued a
Memorandum and Order (LBP-11-24) suspending the proceeding (NRC 2011g).
The NRC staff initiated an orderly closure of its Yucca Mountain activities. As part of the orderly
closure, the NRC staff prepared three technical evaluation reports documenting its work.
Subsequently, the NRC resumed work on its technical and environmental reviews of the
Yucca Mountain application using available funds in response to an August 2013 ruling by the
U.S. Court of Appeals for the District of Columbia Circuit (see Section 1.7.2). The staff
completed and published the final volumes of the safety evaluation report in January 2015
(NRC 2020l). In 2016, the NRC completed and issued a supplement (NUREG-2184; NRC
2016a) to the DOE’s 2002 Yucca Mountain FEIS (DOE 2002) and the DOE’s 2008 Repository
Supplemental EIS (DOE 2008). The NRC’s supplement evaluated the potential environmental
impacts on groundwater and impacts associated with the discharge of any contaminated
groundwater to the ground surface due to potential releases from the proposed Yucca Mountain
geologic repository. The NRC staff evaluated the potential impacts on the aquifer environment,
soils, ecology, and public health, as well as the potential for disproportionate impacts on
minority or low-income populations. The impacts on all of the resources evaluated in the
supplement were found to be SMALL.

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The adjudicatory hearing for the licensing of the repository, which must be completed before a
licensing decision can be made, remains suspended.
The NRC’s nonsensitive Yucca Mountain-related documents have been preserved and made
available to the public as part of the NRC staff’s activities to retain the accumulated knowledge
and experience gained as a result of its Yucca Mountain-related activities. These documents
can be viewed on the NRC’s public website, http://www.NRC.gov/waste/hlw-disposal.html.
NRC decisions and recommendations concerning the ultimate disposition of spent nuclear fuel
are ongoing and outside the scope of license renewal, and as such, are beyond the scope of
this LR GEIS.
Separate from the regulatory actions taken by the NRC, in 2009 and early 2010 the President
and his administration decided not to proceed with the Yucca Mountain nuclear waste
repository. Instead, on January 29, 2010, the Secretary of Energy announced the formation of a
Blue Ribbon Commission to conduct a comprehensive review of policies for managing the back
end of the nuclear fuel cycle (The White House 2010). The Blue Ribbon Commission would
provide advice and make recommendations on issues including alternatives for the storage,
processing, and disposal of civilian and defense spent fuel and HLW. The Blue Ribbon
Commission issued its recommendations to the Secretary of Energy on January 26, 2012
(BRC 2012). The report contained eight key elements:
• A new, consent-based approach to siting future nuclear waste management facilities.
• A new organization dedicated solely to implementing the waste management program and
empowered with the authority and resources to succeed.
• Access to the funds nuclear utility ratepayers are providing for the purpose of nuclear waste
management.
• Prompt efforts to develop one or more geologic disposal facilities.
• Prompt efforts to develop one or more consolidated storage facilities.
• Prompt efforts to prepare for the eventual large-scale transport of spent nuclear fuel and HLW
to consolidated storage and disposal facilities when such facilities become available.
• Support for continued U.S. innovation in nuclear energy technology and for workforce
development.
• Active U.S. leadership in international efforts to address safety, waste management,
nonproliferation, and security concerns.
DOE will be the lead Federal agency responsible for developing a new national strategy for
nuclear waste management; the NRC will play a supporting role in the areas associated with its
regulatory review.
If a repository is not available and away-from-reactor ISFSIs are developed, the operations and
maintenance activities that would be conducted at an away-from-reactor ISFSI would be the
same as those described in NUREG-2157 (NRC 2014c). NUREG-2157 also describes offsite
radiological impacts from the continued storage of spent fuel at an away-from-reactor ISFSI.

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In NUREG-2157, the NRC concluded that a range of potential impacts could occur for some
resource areas if the spent nuclear fuel from multiple reactors is shipped to a large (roughly
40,000 metric tonnes of uranium) away-from-reactor ISFSI (see Section 5.20 of NRC 2014c).
The ranges for some resources are driven by the uncertainty regarding the location of such a
facility and the local resources that would be affected.
For away-from-reactor storage, the unavoidable adverse environmental impacts for most
resource areas are SMALL across all timeframes, except for air quality, terrestrial resources,
aesthetics, waste management, and transportation where the impacts are SMALL to
MODERATE. Socioeconomic impacts range from SMALL (adverse) to LARGE (beneficial) and
historic and cultural resource impacts could be SMALL to LARGE across all timeframes. The
potential MODERATE impacts on air quality, terrestrial wildlife, and transportation are based on
potential construction-related fugitive dust emissions, terrestrial wildlife direct and indirect
mortalities, terrestrial habitat loss, and temporary construction traffic impacts. The potential
impacts on aesthetics and waste management are based on noticeable changes to the
viewshed from constructing a new away-from-reactor ISFSI, and the volume of nonhazardous
solid waste generated by assumed facility ISFSI and Dry Transfer System replacement activities
for the indefinite timeframe, respectively. The potential LARGE beneficial impacts on
socioeconomics are due to local economic tax revenue increases from an away-from-reactor
ISFSI.
The potential impacts on historic and cultural resources during the short-term storage timeframe
would range from SMALL to LARGE. The magnitude of adverse effects on historic properties
and impacts on historic and cultural resources largely depends on where facilities are sited,
what resources are present, the extent of proposed land disturbance, whether the area has
been previously surveyed to identify historic and cultural resources, and if the licensee has
management plans and procedures that are protective of historic and cultural resources. Even a
small amount of ground disturbance (e.g., clearing and grading) could affect a small but
significant resource. In most instances, placement of storage facilities on the site can be
adjusted to minimize or avoid impacts on any historic and cultural resources in the area.
However, the NRC recognizes that this may not always be possible. The NRC’s plant-specific
environmental review and compliance with the NHPA process could identify historic properties,
identify adverse effects, and potentially resolve adverse effects on historic properties and
impacts on other historic and cultural resources. Under the NHPA, mitigation does not eliminate
a finding of adverse effect on historic properties. The potential impacts on historic and cultural
resources during the long-term and indefinite storage timeframes would also range from SMALL
to LARGE. This range takes into consideration routine maintenance and monitoring (i.e., no
ground-disturbing activities), the absence or avoidance of historic and cultural resources, and
potential ground-disturbing activities that could affect historic and cultural resources. The
analysis also considers uncertainties inherent in analyzing this resource area over long
timeframes. These uncertainties include any future discovery of previously unknown historic and
cultural resources and resources that gain significance within the vicinity and the viewshed
(e.g., nomination of a historic district) due to improvements in knowledge, technology, and
excavation techniques and changes associated with predicting resources that future
generations will consider significant. If construction of a Dry Transfer System and replacement
of the ISFSI and Dry Transfer System occurs in an area with no historic or cultural resource
present or construction occurs in a previously disturbed area that allows avoidance of historic
and cultural resources, then impacts would be SMALL. By contrast, a MODERATE or LARGE
impact could result if historic and cultural resources are present at a site and, because they
cannot be avoided, they are affected by ground-disturbing activities during the long-term and
indefinite timeframes.

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Impacts on Federally listed species, designated critical habitat, and EFH would be based on
site-specific conditions and determined as part of consultations required by the ESA and the
Magnuson-Stevens Fishery Conservation and Management Act.
Continued storage of spent nuclear fuel at an away-from-reactor ISFSI is not expected to cause
disproportionately high and adverse human health and environmental effects on minority and
low-income populations. As indicated in the Commission’s policy statement on environmental
justice, if the NRC receives an application for a proposed away-from-reactor ISFSI, a
site-specific NEPA analysis would be conducted, and this analysis would include consideration
of environmental justice impacts. Pursuant to 10 CFR 51.23, the impact determinations for
away-from-reactor storage are presented in NUREG-2157 (NRC 2014c).
The impact levels determined in NUREG-2157 of at-reactor storage, away-from-reactor storage,
and cumulative impacts of continued storage when added to other past, present, and
reasonably foreseeable activities are summarized in Table 6-4 of NUREG-2157 (NRC 2014c).
The impact levels are denoted as SMALL, MODERATE, and LARGE as a measure of their
expected adverse environmental impacts. Most impacts were found to be SMALL and SMALL to
MODERATE. For some resource areas, the impact determination language is specific to the
authorizing regulation, executive order, or guidance. Impact determinations that include a range
of impacts reflect uncertainty related to both geographic variability and the temporal scale of the
analysis. As a result, based on analyses performed in NUREG-2157, the NRC assumes that
further project-specific analysis would be unlikely to result in impact conclusions with different
ranges. The analyses of NUREG-2157 were codified in 10 CFR 51.23 (79 FR 56238).
Per 10 CFR Part 51 Subpart A, the Commission concludes that the impacts presented in
NUREG-2157 would not be sufficiently large to require the NEPA conclusion, for any plant, that
the option of extended operation under 10 CFR Part 54 should be eliminated. Accordingly, while
the Commission has not assigned a single level of significance for the impacts of spent nuclear
fuel and HLW disposal, this issue is considered a Category 1 issue. The staff reviewed
information from SEISs (for initial LRs and SLRs) completed since development of the
2013 LR GEIS and identified no new information or situations that would result in different
impacts for this issue for either an initial LR or SLR term.
4.11.1.4

Mixed Waste Storage and Disposal

This issue addresses the storage and disposal of mixed waste generated at nuclear power
plants and other uranium fuel cycle facilities during the license renewal term. As discussed in
Section 3.11.3, nuclear power plants generate small quantities of mixed waste. Other uranium
fuel cycle facilities are also expected to generate small quantities of mixed waste. Mixed
waste is regulated both by the EPA or the authorized State agency under RCRA and by the
NRC or the Agreement State agency under the Atomic Energy Act of 1954, as amended
(42 U.S.C. § 2011 et seq.). The waste is either treated onsite or sent offsite for treatment
followed by disposal at a permitted site. The comprehensive regulatory controls and the facilities
and procedures that are in place at nuclear power plants ensure that the mixed waste is
properly handled and stored, and that doses to and exposure to toxic materials by the public
and the environment are negligible at all plants. The accumulated quantities of mixed waste
generated onsite needing long-term storage or disposal are expected to increase at a rate
proportional to the length of operation. License renewal (initial LR and SLR) will not increase the
small but continuing risk to human health and the environment posed by mixed waste at all
plants. The radiological and nonradiological environmental impacts from the long-term disposal
of mixed waste from any individual plant at licensed sites are considered SMALL for all sites.

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The staff reviewed information from SEISs (for initial LRs and SLRs) completed since
development of the 2013 LR GEIS and identified no new information or situations that would
result in different impacts for this issue for either an initial LR or SLR term. Therefore, the
environmental impacts associated with mixed waste storage and disposal during the initial LR
and SLR terms would be SMALL for all nuclear plants. This is a Category 1 issue.
4.11.1.5

Nonradioactive Waste Storage and Disposal

This issue addresses the storage and disposal of nonradioactive waste generated at
commercial nuclear power plants and during the rest of the uranium fuel cycle during the license
renewal term. Nonradioactive waste consists of hazardous and nonhazardous waste. Storage
and disposal of hazardous waste generated at nuclear plants are discussed in Section 3.11.2.
As indicated in that section, nuclear plants generate small quantities of hazardous waste during
operation and maintenance. A special class of hazardous waste, known as universal waste,
consisting of commonly used yet hazardous materials (batteries, pesticides, mercury-containing
equipment, and lamps), is also generated. Similar types of hazardous wastes are also
generated at other uranium fuel cycle facilities. The management of hazardous wastes
generated at all of these facilities, both onsite and offsite, is strictly regulated by the EPA or the
responsible State agencies per the requirements of RCRA.
As does any industrial facility, nuclear power plants and the rest of the uranium fuel cycle
facilities also generate nonradioactive, nonhazardous waste (see Section 3.11.4). These wastes
are managed by following good housekeeping practices and are generally disposed of in local
landfills permitted under RCRA Subtitle D regulations.
In the 2013 LR GEIS, the impacts associated with managing nonradioactive wastes at uranium
fuel cycle facilities, including nuclear power plants, were found to be SMALL and designated as
a Category 1 issue. The staff reviewed information from SEISs (for initial LRs and SLRs)
completed since development of the 2013 LR GEIS and identified no new information or
situations that would result in different impacts for this issue for either an initial LR or SLR term.
Therefore, the environmental impacts associated with nonradioactive waste storage and
disposal during the initial LR and SLR terms would be SMALL for all nuclear plants. The
accumulated quantities of nonradioactive waste generated onsite needing long-term storage or
disposal is expected to increase at a rate proportional to the length of operation. It was indicated
that no changes in nonradioactive waste generation would be anticipated for license renewal
(initial LR or SLR), and that systems and procedures are in place to ensure continued proper
handling and disposal of the wastes at all plants. This is a Category 1 issue.

4.12 Greenhouse Gas Emissions and Climate Change
Research indicates that the cause of the Earth’s changing climate and warming over the last
50 to 100 years is the buildup of greenhouse gases (GHGs) in the atmosphere resulting from
human activities (USGCRP 2014; IPCC 2023). The GHGs are well-mixed throughout the Earth’s
atmosphere, and their impact on climate is long-lasting and cumulative in nature as a result of
their long atmospheric lifetime (EPA 2016). The extent and nature of climate change is not
specific to where GHGs are emitted. Climate models indicate that over the next few decades,
temperature increases will continue due to current GHG emission concentrations in the
atmosphere (USGCRP 2014). This is because it takes time for Earth’s climate system to
respond to changes in GHG levels.

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The CEQ has recognized that climate change is a fundamental environmental issue within
NEPA’s purview (88 FR 1196). In accordance with Executive Order 13990, CEQ rescinded draft
guidance entitled, “Draft National Environmental Policy Act Guidance on Consideration of
Greenhouse Gas Emissions,” and on January 9, 2023, issued interim guidance entitled,
“National Environmental Policy Act Guidance on Consideration of Greenhouse Gas Emissions
and Climate Change,” (88 FR 1196) to assist agencies in conducting GHG and climate change
effects analyses on their proposed actions. At the time of publication of this LR GEIS, CEQ had
not finalized the interim guidance.
The effects of a proposed action on climate change can be evaluated by quantifying the
proposed action’s GHG emissions. Therefore, the contribution to GHG emissions over the
license renewal term serves as proxy in assessing the impact from continued power plant
operation on climate change. Changes in climate have broader implications for environmental
resources (e.g., water resources, air quality, and ecosystems). For instance, changes in
precipitation patterns and increase in air temperature can affect water availability and quality. As
a consequence, climate change can have overlapping impacts on environmental resources by
inducing changes in resource conditions that can also be affected by the proposed action.
Based on these considerations, the following two issues are considered in this section:
• greenhouse gas impacts on climate change (new issue not considered in the 2013 LR GEIS)
• climate change impacts on environmental resources (new issue not considered in the
2013 LR GEIS)
4.12.1

Greenhouse Gas Impacts on Climate Change

The issue of GHG impacts on climate change associated with nuclear power plant operations
was not identified as either a generic or plant-specific issue in the 2013 LR GEIS. In the
2013 LR GEIS, the NRC staff presented GHG emission factors associated with the nuclear
power life cycle.
At the time of publication of the 2013 LR GEIS, insufficient data existed to support a
classification of GHG emission impacts and climate change as a generic or plant-specific issue.
The 2013 LR GEIS, however, included a discussion summarizing nuclear power plant-based
GHG emissions and climate change. Furthermore, following the issuance of Commission order
CLI-09-21 (NRC 2009d), the NRC began to evaluate the effects of GHG emissions in
environmental reviews for license renewal applications.
Impacts on climate change during normal operations at nuclear power plants can result from the
release of GHGs from stationary combustion sources (e.g., diesel generators, pumps, diesel
engines, boilers), refrigeration systems, electrical transmission and distribution systems, and
mobile sources (worker vehicles and delivery vehicles) (see Section 3.12). The GHG emissions
from nuclear power plants are typically very minor because such plants do not normally
combust fossil fuels to generate electricity. As can be observed from Table 3.12-2, direct and
indirect GHG emissions from operations at nuclear power plants rarely exceed the 25,000 MT
(27,557 T) of carbon dioxide equivalents (CO2eq) reporting threshold established by EPA.
Furthermore, when compared to State GHG emission inventories (see Table 3.12-1), GHG
emissions from operating nuclear power plants are orders of magnitude lower. When compared
to different GHG emission inventories for other facilities, GHG emissions from nuclear power
plant operations are minor. For example, in the initial LR SEISs for Byron, Fermi, LaSalle, River
Bend, and Waterford, the NRC compared the nuclear plant’s GHG emissions to total annual

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county-level GHG emissions (NRC 2015c, NRC 2016c, NRC 2016d, NRC 2018c, NRC 2018d).
The GHG emissions from these nuclear power plants ranged from less than 0.03 to about
3.9 percent of their respective county’s total GHG emissions. In the Peach Bottom SLR SEIS,
the NRC concluded that continued operation would result in at least 4.4 million T/yr (3.9 million
MT/yr) of CO2eq emissions avoidance compared to other replacement energy (power)
alternatives (e.g., supercritical pulverized coal, natural gas-combined cycle, and combination
alternatives) (NRC 2020g). Similarly, in the Surry SLR SEIS, the NRC concluded that
continued operation would result in at least 4.8 million T/yr (4.3 million MT/yr) of CO2eq
emission avoidance when compared to replacement energy alternatives considered (natural
gas-combined cycle and combination alternative) (NRC 2020f).
Potential sources of GHG emissions during any license renewal refurbishment activities include
motorized equipment, construction vehicles, and worker vehicles. Construction vehicles and
other motorized equipment would generate exhaust emissions that include GHG emissions
(primarily CO2). These emissions, however, would be intermittent, temporary, and restricted to
the refurbishment period. The GHG emissions would result primarily from the additional
workforce. Findings from SEISs completed since development of the 2013 LR GEIS have
shown that the duration of refurbishment activities would occur over a 2 to 3 month period and
would require an additional 500 to 1,400 workers. The NRC estimates that this can result in up
to an additional 5,800 T (5,260 MT)17 of CO2eq (NRC 2015d, NRC 2015e, NRC 2018e).
Emissions of GHGs from worker vehicles during refurbishment would be similar to those during
normal nuclear power plant operations (see indirect emissions presented in Table 3.12-2).
Therefore, GHG emissions from refurbishment activities would be minor.
Based on these considerations, the NRC concludes that the impacts of GHG emissions on
climate change from continued operations and refurbishment during the initial LR and SLR
terms and any refurbishment activities would be SMALL for all plants. This is a new Category 1
issue.
4.12.2

Climate Change Impacts on Environmental Resources

The issue of climate change impacts was not identified as either a generic or plant-specific
issue in the 2013 LR GEIS. However, the 2013 LR GEIS described the environmental impacts
that could occur on resource areas (land use, air quality, water resources, etc.) that are affected
by the proposed action (license renewal). Climate change is an environmental trend (i.e.,
change in climate indicators such as precipitation over time) that could result in changes to the
affected environment irrespective of license renewal. In plant-specific initial LR and SLR SEISs
prepared since development of the 2013 LR GEIS, the NRC has considered climate change
impacts for those resources that could be incrementally affected by the proposed action as part
of the cumulative impacts analysis. As discussed in Section 3.12 of this LR GEIS, climate
change and its impacts on resources can vary regionally. Observed climate change has not
been uniform across the United States. For instance, annual precipitation has increased across
most of the northern and eastern States and decreased across the southern and western
States; along the Atlantic coast in the Northeast region, sea surface temperatures and sea level
rise have increased at rates that exceed global averages; the Southeast region has not
experienced an overall long-term increase in surface temperatures; the Northwest experienced
the smallest increase in heavy precipitation events of any region in the United States.

17

Calculated by conservatively assuming a 90-day refurbishment duration, 1,400 worker vehicles, 100 mi
(160 km) round trip travel per vehicle, and 420 grams of CO2eq/mi (DOE 2021a).

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Climate change may impact the affected environment in a way that alters the environmental
resources that are impacted by the proposed action (license renewal). Similar to cumulative
impacts, climate change impacts can occur across all resource areas that could be affected by
the proposed action, including the effects of continued reactor operations during the license
renewal term and any refurbishment activities at a nuclear power plant. In order for there to be a
climate change impact on an environmental resource, the proposed action (license renewal)
must have an incremental new, additive, or increased physical effect or impact on the resource
or environmental condition beyond what is already occurring. The goal of the climate change
impacts analysis is to identify potentially significant impacts.
Future global GHG emission concentrations (emission scenarios) and climate models are
commonly used to project possible climate change. Climate models indicate that over the next
few decades, temperature increases will continue due to current GHG emission concentrations
in the atmosphere (USGCRP 2014). If GHG concentrations were to stabilize at current levels,
this would still result in at least an additional 1.1°F (0.6°C) of warming over this century
(USGCRP 2018). Over the longer term, the magnitude of temperature increases and climate
change related effects will depend on future global GHG emissions (IPCC 2021;
USGCRP 2009, USGCRP 2014, USGCRP 2018). Climate model simulations often use GHG
emission scenarios to represent possible future social, economic, technological, and
demographic development that, in turn, drive future emissions. Consequently, the GHG
emission scenarios, their supporting assumptions, and the projections of possible climate
change effects entail substantial uncertainty.
The Intergovernmental Panel on Climate Change (IPCC) has generated various representative
concentration pathway (RCP) scenarios commonly used by climate modeling groups to project
future climate conditions (IPCC 2000, IPCC 2013, USGCRP 2017, USGCRP 2018). In the IPCC
Fifth Assessment Report, four RCPs were developed and are based on the predicted changes
in radiative forcing (a measure of the influence that a factor, such as GHG emissions, has in
changing the global balance of incoming and outgoing energy) in the year 2100, relative to
preindustrial conditions. The four RCP scenarios are numbered in accordance with the change
in radiative forcing measured in watts per square meter (i.e., +2.6 [very low], +4.5 [lower],
+6.0 [mid-high], and +8.5 [higher]) (USGCRP 2018). For example, RCP2.6 is representative of a
mitigation scenario aimed at limiting the increase of global mean temperature to 1.1°F (2°C)
(IPCC 2014). The RCP8.5 reflects a continued increase in global emissions resulting in
increased warming by 2100. In the IPCC Working Group contribution to the Sixth Assessment
Report, five shared socioeconomic pathways were used along with associated modeling results
as the basis for their climate change assessments (IPCC 2021). These five socioeconomic
pathway scenarios cover a range of greenhouse pathways and climate change mitigation.
The Fourth National Climate Assessment relies on the four RCPs in the IPCC Fifth Assessment
Report and presents projected climate change categorized by U.S. geographic region (see
Figure 3-12; USGCRP 2018). Similar to the observed climate changes categorized by U.S.
geographic region, as discussed in Section 3.12 of this LR GEIS, climate model projections
indicate that changes in climate will not be uniform across the United States. Observed and
projected differences in climate changes in the United States are further presented in initial LR
and SLR SEISs prepared since 2013. For instance, the Point Beach plant SLR SEIS states that
climate models predict an increase of 4–6°F (2.2–3.3°C) in annual mean temperature for
Wisconsin under the RCP4.5 and RCP8.5 scenarios for the midcentury (NRC 2021f). The
Turkey Point plant SLR SEIS indicates that for the same scenarios and timeframe, climate
models predict an increase in the annual mean temperature of 2–4°F (1.1–2.2°C) for Florida
(NRC 2019c).

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The North Anna and the Surry SLR SEISs discuss climate change projections in the Northeast
region and the Commonwealth of Virginia, along with associated impacts on the environment. In
the Surry plant SLR SEIS, the NRC considered the salinity effects of sea level rise projections
on the James River and deterioration of surface water quality due to saltwater intrusion
(NRC 2021g). Unlike Surry, North Anna is not located on a tidal river but on the Lake Anna
Reservoir, which is not directly affected by sea level changes along the Atlantic coast.
Consequently, sea level rise projections were not pertinent in the consideration of climate
change impacts to surface water quality in the North Anna SEIS. The Turkey Point plant SLR
SEIS and the Waterford plant initial LR SEIS considered the impacts of projected sea level rise.
However, these SEISs illustrate how sea levels can affect water resources differently. As noted
in the Waterford plant initial LR SEIS, projected sea level rise could increase the upstream
migration of the saltwater wedge, which could cause a general deterioration in surface water
quality in the Lower Mississippi River (NRC 2018d). However, as noted in the Turkey Point SLR
SEIS for South Florida, higher sea levels will increase the rate of saltwater intrusion leading to
the degradation of groundwater quality of aquifers designated as sources of drinking water
(NRC 2019c).
While sea level rise impacts may occur in certain areas, decreases in water levels for the
Great Lakes are projected for the future. For instance, the Fermi plant initial LR SEIS and the
Point Beach SLR SEIS both discuss that, while long-term water level projections are uncertain,
model simulations indicate a future decline in lake levels for Lake Erie and Lake Michigan due to
increases in evaporative losses and warmer water temperatures (NRC 2016c; NRC 2021f).
Higher surface water temperatures can result in a decrease in cooling efficiency and therefore
have the potential to increase the use of cooling water and result in a slightly larger volume of
heated water discharged back to the lake (NRC 2016c; NRC 2021f).
Based on these considerations, the NRC concludes that the impacts of climate change on
environmental resources that are directly affected by continued nuclear power plant operations
and any refurbishment during the initial LR and SLR terms are location-specific and cannot be
evaluated generically. Changes in climate parameters and trends (e.g., temperature,
precipitation, floods, storm frequency, sea level rise) affect environmental resource baseline
conditions (i.e., the affected environment) that are incrementally affected by license renewal,
thereby changing the future state of the environment. The effects of climate change can vary
regionally, and climate change information at the regional and local scale is necessary to
assess the trends and impacts on the human environment for a specific location. Therefore, this
is a new Category 2 issue because it requires a plant-specific evaluation.

4.13 Cumulative Effects of the Proposed Action
Actions considered in the cumulative effects (impacts) analysis include the proposed license
renewal action (initial LR or SLR) when added to past, present, and reasonably foreseeable
actions, including projects and programs that are conducted, regulated, or approved by a
Federal agency. The analysis takes into account all actions, however minor, because the effects
of individually minor actions may be significant when considered collectively over time. The goal
of the cumulative effects analysis is to identify potentially significant impacts.

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Definition of Cumulative Effects
Effects on the environment that result from the incremental effects of the action when added
to the effects of other past, present, and reasonably foreseeable actions regardless of what
agency (Federal or non-Federal) or person undertakes such other actions. Cumulative effects
can result from actions with individually minor but collectively significant effects taking place
over a period of time (40 CFR 1508.1)(i)(3)).
The cumulative effects or impacts analysis only considers resources and environmental
conditions that could be affected by the proposed license renewal action, including the effects of
continued reactor operations during the license renewal term and any refurbishment activities at
a nuclear power plant. In order for there to be a cumulative effect, the proposed action (license
renewal) must have an incremental new, additive, or increased physical effect or impact on the
resource or environmental condition beyond what is already occurring.
The CEQ’s report, Considering Cumulative Effects Under the National Environmental Policy Act,
provides a framework for addressing the cumulative effects of the proposed action in an EIS
(CEQ 1997a). Using guidance from the CEQ report, the cumulative effects analysis considers
the following:
• The geographic region of influence that encompasses the areas of potential effect and the
distance at which the environmental effects of the proposed action and past, present, and
reasonably foreseeable actions may be experienced. Geographic regions of influence vary by
affected resource.
• The timeframe for the cumulative effects analysis incorporates the incremental effects of the
proposed action (license renewal) with past, present, and reasonably foreseeable actions
because these combined effects may accumulate or develop over time. Past and present
actions include all actions up to and including the date of the license renewal request. The
timeframe for the consideration of reasonably foreseeable actions is the 20-year license
renewal (initial LR or SLR) term. Reasonably foreseeable actions include current and ongoing
planned activities, approved and funded for implementation.
• The environmental effects from past and present actions are accounted for in baseline
assessments presented in affected environment discussions in Chapter 3 of this LR GEIS.
Chapter 4 accounts for the incremental effects or impacts of the proposed action (license
renewal).
• The incremental effects of the proposed action (license renewal) when added to the effects
from past, present, and reasonably foreseeable actions result in the overall cumulative effect.
A qualitative cumulative effects analysis is conducted in instances where the incremental
effects of the proposed action (license renewal) and past, present, and reasonably
foreseeable actions are uncertain or not well known.
• For some resource areas (e.g., water resources, aquatic resources, and human health), the
incremental contributions of ongoing actions within a region are managed and/or monitored
through an established regulatory process (e.g., CWA Section 402 pursuant to 40 CFR
Part 122 [NPDES program], 10 CFR Part 20 [NRC radiological protection], 29 CFR Part 1910
[Occupational safety and health]) under State and/or Federal authority. In these cases, it may
be assumed that cumulative effects are managed as long as these actions (facility operations)
comply with the respective regulations, permits, or operating license.

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The following sections discuss the potential for cumulative effects to occur in environmental
resources near a nuclear power plant—when the incremental environmental effects of the
proposed license renewal action are compounded by the effects from past, present, and
reasonably foreseeable actions. For the most part, environmental conditions near the nuclear
power plant are not expected to change appreciably during the license renewal term beyond
what is already being experienced. Because environmental conditions are different at every
nuclear power plant, cumulative effects is a Category 2 issue requiring a plant-specific analysis
during the license renewal environmental review.
The staff reviewed information from SEISs (for initial LRs and SLRs) completed since
development of the 2013 LR GEIS. Based on the information reviewed and the preceding
discussion, the NRC concludes that cumulative effects during the initial LR and SLR terms and
refurbishment are unique to each nuclear power plant. Therefore, the cumulative effects of
license renewal cannot be determined generically and it is a Category 2 issue.
4.13.1

Air Quality

Regional air quality conditions, due to past and present activities, could be affected by the
emissions from continued reactor operations and refurbishment at a nuclear power plant when
combined with the emissions from planned industrial, commercial, agricultural, and
transportation development. These activities generate dust and emissions—affecting regional
air quality. The magnitude of the cumulative effect depends on the location of the nuclear power
plant, intensity of planned development, and the presence of air quality nonattainment areas.
4.13.2

Surface Water Resources

Surface water withdrawals, effluent discharges, stormwater runoff, and accidental spills and
releases and their impacts on water quality and availability could increase due to the combined
effects of continued reactor operations and refurbishment, and existing and planned industrial,
commercial, and agricultural development activities. The incremental effect of the proposed
action, continued surface water withdrawal for nuclear power plant cooling systems (both
once-through and closed-cycle), generally has had the greatest contributory effect. Water
withdrawal for nuclear plant cooling often conflicts with the water needs of other surface water
users. The magnitude of the cumulative effect depends on the location of the nuclear power
plant, intensity of existing and planned development activities, and affected surface water
resources.
4.13.3

Groundwater Resources

Groundwater demands and groundwater quality impacts could increase because of the
combined effects of continued reactor operations and refurbishment, and existing and planned
industrial, commercial, and agriculture development activities. The magnitude of the cumulative
effect depends on the location of the nuclear power plant, intensity of existing and planned
development activities that withdraw water, water demand, and the hydrogeologic
characteristics of the affected aquifers.
4.13.4

Ecological Resources

Terrestrial wildlife impacts include habitat loss and degradation, disturbance and displacement,
injury and mortality, and obstruction of movement due to the combined effects of continued
reactor operations and refurbishment, and existing and planned industrial, commercial, and

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agriculture development activities. Other impacts include exposure to noise and contaminants,
altered surface water and groundwater quality and flow patterns, and collisions with buildings
and other structures. Adverse effects typically result from construction activities associated with
planned industrial and commercial development, agriculture, transportation, water projects, and
tourism and recreation. Migratory bird species may be affected by activities occurring away from
the nuclear power plant. Ecological communities (including floodplain and wetland) may also be
affected by development activities (e.g., land clearing and grading) that create conditions that
favor invasive species. The magnitude of the cumulative effect depends on the location of the
nuclear power plant relative to important wildlife habitats and ecological communities, and the
intensity of existing and planned development activities.
There are three scales of aquatic resource effects: (1) cumulative effects from the nuclear
power plant (e.g., entrainment, impingement, thermal discharges, and chemical discharges),
(2) cumulative effects from other power plants, and (3) cumulative effects from activities
affecting waterbodies (e.g., dams, agriculture, urban, and industrial development). Aquatic
impacts include the (1) loss and degradation of habitat; (2) species disturbance, displacement,
injury, and mortality; (3) obstruction of movement; and (4) the introduction and spread of
invasive species due to the combined effects of continued reactor operations and refurbishment,
and existing and planned industrial, commercial, and agriculture development activities. These
effects result in increased water use and discharges to natural waterbodies; increased and
contaminated runoff from planned industrial, commercial, agriculture, and transportation
development. water projects. and tourism and recreation. Similarly, the magnitude of the
cumulative effect depends on the location of the nuclear power plant relative to important
waterbodies and the intensity of existing and planned development activities.
4.13.5

Historic and Cultural Resources

Historic and cultural resources (e.g., archaeological sites, historic structures, and traditional
cultural properties) could be adversely affected by ground-disturbing maintenance and
refurbishment activities at a nuclear power plant and by planned industrial and commercial
development. Historic and cultural resource impacts from ground-disturbing activities (e.g., land
clearance, grading, and excavation) could occur during the construction of planned industrial,
commercial, and transportation infrastructure and maintenance activities—damaging or
destroying cultural material. The magnitude of the cumulative effect depends on the location of
the nuclear power plant, intensity of planned development, and mitigation.
4.13.6

Socioeconomics

Employment and income generated by the combined effects of continued reactor operations
and refurbishment and industrial, commercial, and housing development can have a significant
cumulative socioeconomic effect. Income generated from goods and services creates additional
employment and income opportunities. New employment could increase the population and
demand for public services, housing, and transportation. The magnitude of the cumulative
socioeconomic effect depends on the location of the nuclear power plant and the intensity of
development.
4.13.7

Human Health

Exposure to radiological, chemical, and microbiological hazards and the potentially chronic
effects of EMFs could result in a cumulative health effect. Exposure may occur as a result of the
accumulation of harmful constituents released from existing facilities and planned industrial and

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commercial development. The magnitude of the cumulative human health effect depends on the
location of past, present, and reasonably foreseeable actions, the number of facilities and
activities involving radiological and hazardous material, and the amount of exposure.
4.13.8

Environmental Justice

The cumulative effects of license renewal (proposed action) at a nuclear power plant, combined
with the environmental effects of past, present, and reasonably foreseeable actions, could
exacerbate any human health or environmental effects in a minority population, low-income
population, or Indian Tribe. In addition, the combined effects of license renewal and industrial,
commercial, and housing development near the nuclear plant could disproportionately affect
consumption patterns (e.g., subsistence agriculture, hunting, and fishing) and the environmental
resources on which these populations may depend (e.g., fish, wildlife, and local produce).
Whether these effects are disproportionately high and adverse depends on the unique
characteristics of these populations and their proximity to the nuclear power plant and planned
development.
4.13.9

Waste Management and Pollution Prevention

Nuclear power plants, uranium fuel cycle facilities, and other commercial industrial facilities
generate radioactive and nonradioactive waste material. Depending on the location of waste
treatment and disposal facilities, nearby communities and people could experience the
cumulative effects of transportation, treatment, and disposal activities. However, some nuclear
power plants may be the only radioactive waste generator in a region. All commercial industrial
waste-generating facilities must comply with Federal and State waste storage, treatment, and
disposal regulations. These facilities must also ensure waste is properly handled and stored and
its release is closely monitored. The magnitude of the cumulative effect depends on the location
of past, present, and reasonably foreseeable actions involving facilities and activities that
generate, treat, and store radiological and hazardous waste material.

4.14 Impacts Common to All Alternatives
This section describes impacts that are considered common to all alternatives discussed in this
LR GEIS, focusing on the proposed action (initial LR or SLR). The continued operation of a
nuclear power plant involves the mining, processing, and consumption of fuel, which results in
environmental impacts. Environmental impacts associated with the uranium fuel cycle are
presented in Section 4.14.1. The environmental impacts associated with replacement energy
alternative fuel cycles are presented in Appendix D, Section D.4.12. The impacts of license
renewal on termination of operations and the decommissioning of a nuclear power plant are
presented in Section 4.14.2.1. The environmental impacts of termination of operations and
decommissioning replacement energy facilities are provided in Appendix D (Section D.4.13).
4.14.1

Environmental Consequences of the Uranium Fuel Cycle

Nuclear power plants obtain the uranium from the Earth and refine it for its use within the
reactors. The continued operation of the nuclear power plants during the license renewal term
(initial LR or SLR) requires uranium processing. Getting fuel may include extracting,
transforming, transporting, and combusting, among other activities. Emissions may result at
each step within the processing. Also, some aspects of any fuel cycle (for example, storage and
disposal) described here are common to each alternative.

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In the United States, all currently operating commercial plants are LWRs and use uranium for
fuel. Therefore, in this section and in the rest of this LR GEIS, the term “uranium fuel cycle” is
used interchangeably with “nuclear fuel cycle.”
4.14.1.1

Background on Uranium Fuel Cycle Facilities

The NRC evaluated the environmental impacts that would be associated with operating uranium
fuel cycle facilities other than the reactors themselves in two NRC publications: WASH-1248
(AEC 1974a) and NUREG-0116 (NRC 1976). More recently, facilities for managing the back
end of the nuclear fuel cycle were considered in NUREG-2157 (NRC 2014c). The types of
facilities considered in these documents include the following:
• uranium mining – facilities where the uranium ore is mined
• uranium milling – facilities where the uranium ore is refined to produce uranium concentrates
in the form of triuranium octaoxide (U3O8)
• UF6 production – facilities where the uranium concentrates are converted to UF6
• isotopic enrichment – facilities where the isotopic ratio of the uranium-235 isotope in natural
uranium is increased to meet the requirements of LWRs
• fuel fabrication – facilities where the enriched UF6 is converted to uranium dioxide and made
into sintered uranium dioxide pellets. The pellets are subsequently encapsulated in fuel rods,
and the rods are assembled into fuel assemblies ready to be inserted into the reactors. Two
options were considered: (1) carrying out all steps involved in manufacturing the fuel
assemblies at the same location, and (2) carrying the steps out at two separate facilities
(at one facility, uranium dioxide is produced in powder form from the enriched UF6; and at the
other facility, the fuel assemblies are manufactured).
• reprocessing – facilities that disassemble the spent fuel assemblies, chop up the fuel rods into
small sections, chemically dissolve the spent fuel out of sectioned fuel rod pieces, and
chemically separate the spent fuel into reusable uranium, plutonium, and other radionuclides
(primarily fission products and actinides)
• ISFSIs – Two options are considered:
–

At-Reactor Continued Storage ISFSIs – facilities designed and constructed at a nuclear
power plant for the interim storage of spent nuclear fuel pending permanent disposal,
used by operating plants to add spent nuclear fuel storage capacity beyond that
available in the nuclear power plant’s SFP.

–

Away-from-Reactor ISFSIs – facilities designed and constructed away from a nuclear
power plant for the short-term, long-term, and indefinite storage of spent nuclear fuel
pending permanent disposal, used by operating and formerly operating nuclear plants to
add spent nuclear fuel storage capacity beyond that available in the nuclear power
plant’s SFP and at-reactor ISFSIs.

• disposal – facilities where the radioactive wastes generated at all fuel cycle facilities, including
the reactors, are buried. Spent nuclear fuel that is removed from the reactors and not
reprocessed was also assumed to be disposed of at a geologic repository.
As evaluated in NUREG-2157 (NRC 2014c), the NRC reaffirmed in 2014 that geological
disposal remains technically feasible and that acceptable sites can be identified.

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4.14.1.2

Environmental Impacts

In addition to impacts occurring at the above facilities, the impacts associated with the
transportation of radioactive materials among these facilities, including the transportation of
wastes to disposal facilities, were evaluated. The results were summarized in a table and
promulgated as Table S-3 in 10 CFR 51.51(b). Table S-3 is provided at the end of this section
as Table 4.14-118 for ease of reference. 10 CFR 51.51(a) states:
Every environmental report prepared for the construction permit stage of a lightwater-cooled nuclear power reactor, and submitted on or after September 4,
1979, shall take Table S-3, Table of Uranium Fuel Cycle Environmental Data, as
the basis for evaluating the contribution of the environmental effects of uranium
mining and milling, the production of uranium hexafluoride, isotopic enrichment,
fuel fabrication, reprocessing of irradiated fuel, transportation of radioactive
materials and management of low level wastes and high level wastes related to
uranium fuel cycle activities to the environmental costs of licensing the nuclear
power reactor. Table S-3 shall be included in the environmental report and may
be supplemented by a discussion of the environmental significance of the data
set forth in the table as weighed in the analysis for the proposed facility.
Specific categories of natural resource use included in Table 4.14-1 relate to land use; water
consumption and thermal effluents; radioactive releases; burial of transuranic waste, HLW, and
LLW; and radiation doses from transportation and occupational exposures. The contributions in
the table for reprocessing, waste management, and transportation of wastes are maximized for
either of the two fuel cycles (uranium only and no recycle); that is, the cycle that results in the
greater impact is used. For each resource area, Table 4.14-1 presents a result that has been
integrated over the entire fuel cycle except the reactors. The only exception to this is that the
waste quantities provided under the entry called “solids (buried onsite)” also includes wastes
generated at the reactor.
The environmental impact values are expressed in terms normalized to show the potential
impacts attributable to processing the fuel required for the operation of a 1,000 megawatt
electric (MWe) nuclear power plant for 1 year at an 80 percent availability factor to produce
about 800 megawatts (MW)-yr (0.8 gigawatts-yr) of electricity. This is referred to as 1 reference
reactor year.
Many of the nuclear fuel cycle facilities and processes assessed for Table 4.14-1 still exist
today. However, some have undergone several industrial developments and technological
advances that have significantly reduced their environmental effects. As discussed in
NUREG-2226, the Clinch River early site permit FEIS (NRC 2019b), recent changes in the
uranium fuel cycle may have some bearing on environmental impacts. As discussed below, the
NRC is confident that the contemporary normalized uranium fuel cycle impacts for LWRs are
less than those identified in Table 4.14-1. This assertion is true in light of the following recent
uranium fuel cycle trends in the United States:
• Increasing use of in situ leach uranium mining, which does not produce mine tailings and
would lower the release of radon gas (NRC 2009g).
In Table 4.14-1, the units of measurement provided in the “Environmental Considerations” subheadings
apply for the items within that environmental consideration. For example, under the environmental
consideration of “Water,” the units of millions of gallons also apply to the items “Discharged to air;”
“Discharged to waterbodies;” and “Discharged to ground.”
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• Transitioning of U.S. uranium enrichment technology from gaseous diffusion to gas
centrifugation. The latter process uses only a fraction of the electrical energy per separation
unit compared to gaseous diffusion and U.S. gaseous-diffusion plants that relied on electricity
derived mainly from the burning of coal.
• Current LWRs are using nuclear fuel more efficiently because of higher levels of fuel burnup.
Thus, less uranium fuel per year of reactor operation is required than in the past to generate
the same amount of electricity (an increase in the time for refueling [from 12 months to
18 months or more] as applied for Table S–3).
The values in Table 4.14-1 were calculated from industry averages for the performance of each
type of facility or operation within the fuel cycle. Recognizing that this approach meant that there
would be a range of reasonable values for each estimate, the staff chose the assumptions or
factors to be applied so that the calculated values would not be underestimated. This approach
was intended to make sure that the actual environmental impacts would be less than the
quantities shown in Table 4.14-1 for all LWR nuclear power plants within the widest range of
operating conditions. The staff recognizes that many of the fuel cycle parameters and
interactions vary in small ways from the estimates in Table 4.14-1 and concludes that these
variations would have no impacts on the Table 4.14-1 calculations. For example, to determine
the quantity of fuel required for a year’s operation of a nuclear power plant in Table 4.14-1, the
staff defined the reference reactor as a 1,000 MW LWR operating at 80 percent capacity with a
12-month fuel-reloading cycle and an average fuel burnup of 33,000 megawatt-days per metric
tonne of uranium (MWd/MTU). These values are not challenged by the current LWR fleet, which
is operating with an average factor of approximately 95 percent capacity for peak fuel rod
burnup of up to 62,000 MWd/MTU with refueling occurring at approximately 18-months to 2-year
intervals (NRC 2019b). This means fuel can be used more efficiently, requiring less total fuel,
resulting in less environmental effects than those presented in Table 4.14-1 (Table S–3).
The analysis presented in Table 4.14-1 (circa 1970s) was also based on most of the electricity
generated in the United States being produced in plants that burn fossil fuels, and coal
composing the bulk of fossil fuel utilization (AEC 1974a). However, today the energy sources for
utility-scale electrical generation are more diverse (DOE/EIA 2023a):
• 19.5 percent from coal
• 39.8 percent from natural gas, for which air emissions are much less than those from coal
• 18.2 percent from nuclear power plants
• 21.5 percent from renewables (15.3 percent from non-hydroelectric renewables and
6.2 percent from hydroelectric)
• 1 percent from petroleum and other sources
Table S-3 of 10 CFR 51.51(b) does not provide an estimate of GHG emissions associated with
the uranium fuel cycle; it only addresses pollutants that were of concern when the table was
promulgated in the 1980s. However, Table S-3 states that 323,000 MWh is the assumed annual
electric energy use for the reference 1,000 MWe nuclear power plant and that this
323,000 MWh of annual electric energy is assumed to be generated by a 45 MWe coal-fired
power plant burning 130,000 T (118,000 MT) of coal. Table S-3 also assumes that
approximately 135,000,000 standard cubic feet (scf) (3,823,000 m3) of natural gas is required
per year to generate process heat for certain portions of the uranium fuel cycle. The NRC staff

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has projected that burning 130,000 T (118,000 MT) of coal and 135,000,000 scf (3,823,000 m3)
of natural gas per year results in approximately 279,000 T (253,000 MT) of CO2eq being emitted
into the atmosphere per year because of the uranium fuel cycle (Harvey 2013).
This emissions estimate is based on the assumption in WASH-1248 (AEC 1974a) that all
electricity use is provided for by coal. Applying the analysis of Harvey (2013) and electricity
generation by coal now approximately 19.5 percent and approximately 39.8 percent from natural
gas, the current uranium fuel cycle would emit approximately 118,000 T (107,000 MT) CO2e
from electrical usage and process heating with natural gas, or only about 42 percent of the
calculated Table S-3 CO2e emissions. As discussed in Section 3.12.1, annual GHG emissions
in the United States totaled 6,988.8 million T (6,340 million MT) CO2eq in 2021. Thus, the
uranium fuel cycle contribution is a very small fraction of the Nation’s annual GHG emissions.
Therefore, environmental impacts related to air emissions, associated pollutants, and
water/thermal impacts from today’s electrical generation contribution to the nuclear fuel cycle
are clearly less than and are bounded by the coal-electrical generation data assessed by
WASH-1248 (AEC 1974a) and found in Table 4.14-1. This trend of decreasing reliance on fossil
fuels for electrical generation will continue, spurred by actions to reduce GHG emissions
(DOE/EIA 2023b).
Based on several of the items discussed above, the 2013 LR GEIS states:
It was concluded that even though certain fuel cycle operations and fuel
management practices have changed over the years, the assumptions and
methodology used in preparing Table S–3 were conservative enough that the
impacts described by the use of Table S–3 would still be bounding. The NRC
believes that this conclusion still holds.
A detailed discussion of impacts associated with the production and processing of fuel needed
for 1 reference reactor year operation of the model LWR was provided in the 1996 LR GEIS
(NRC 1996). Included in the discussion were the collective offsite radiological impacts that
would be associated with radon-222 and technetium-99 releases to the environment during the
fuel cycle operations, which Table 4.14-1 does not address.
One part of the fuel cycle that was not discussed, either in the technical support documents for
the original Table 4.14-1 or in the 1996 LR GEIS, was the disposition of the depleted UF6 tails
generated during the enrichment process. Originally, these tails were intended to be used as a
feedstock to make fuel for proposed fast breeder reactors. However, the United States
abandoned the fast breeder reactor program in 1983 (Breeder Reactor Corporation 1985).
Before the creation of the United States Enrichment Corporation in 1993, DOE was the
custodian of all the depleted UF6 generated in the United States at the three gaseous-diffusion
plants (in Oak Ridge, Tennessee; Portsmouth, Ohio; and Paducah, Kentucky). DOE prepared
several NEPA documents evaluating the impacts associated with the disposition of
approximately 700,000 MT (1.54 billion lb) of depleted UF6 (DOE 1999, DOE 2004a,
DOE 2004b, DOE 2020). DOE decided to convert the depleted UF6 back to U3O8 and dispose of
it as LLW (69 FR 44654, 69 FR 44649, 85 FR 34610). The results of these analyses indicate
that the operational impacts of the depleted UF6 management facilities would not be very
different from the impacts estimated for other parts of the fuel cycle in Table 4.14-1. In
particular, the impacts of the depleted UF6 conversion facilities, where the depleted UF6 is
converted to triuranium octaoxide, would be similar to the impacts of the UF6 production
facilities, where U3O8 is converted to UF6. If the depleted uranium oxide is disposed of as LLW,
the conversion product corresponding to 1 reference reactor year would be in addition to the

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LLW quantities already listed in Table 4.14-1. This value is estimated to be approximately 12 Ci
(4.4  1011 Bq) (35 MT of uranium per reference reactor year multiplied by 0.34 Ci/MT of
depleted uranium).
As discussed above and in the following sections, the NRC staff reviewed information from
technical literature as well as from SEISs (for initial LRs and SLRs) completed since
development of the 2013 LR GEIS and identified no new information or situations that would
result in different impacts for either an initial LR or SLR term with respect to the uranium fuel
cycle.
Table 4.14-1 Table S-3 Taken from 10 CFR 51.51 on Uranium Fuel Cycle Environmental
Data (Normalized to model light water reactor annual fuel requirement
[WASH-1248; AEC 1974a] or reference reactor year [NUREG-0116;
NRC 1976])(a)

Environmental Considerations

Maximum Effect per Annual Fuel
Requirement or Reference Reactor Year of
Model 1,000 MWe Light Water Reactor

Total

Natural Resource Use
Land (acres)
Temporarily committed(b)

100

Undisturbed area

79

Disturbed area

22

Permanently committed

13

Overburden moved (millions of MT)

2.8

Equivalent to 95 MWe coal-fired power plant.

160

Equal to 2 percent of model 1,000 MWe light
water reactor with cooling tower.

Equivalent to a 110 MWe coal-fired power plant.

Water (millions of gallons)
Discharged to air
Discharged to waterbodies
Discharged to ground
Total

11,090
127
11,377

Less than 4 percent of model 1,000 MWe light
water reactor with once-through cooling.

Fossil Fuel
Electrical energy (thousands of
MW-hour)

323

Less than 5 percent of model 1,000 MWe output.

Equivalent coal (thousands of MT)

118

Equivalent to the consumption of a 45 MWe coalfired power plant.

Natural gas (millions of scf)

135

Less than 0.4 percent of model 1,000 MWe
energy output.

Effluents − Chemical (MT)
Gases (including entrainment)(c)
SOx

4,400

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Environmental Considerations
(d)

NOx

Hydrocarbons

Maximum Effect per Annual Fuel
Requirement or Reference Reactor Year of
Model 1,000 MWe Light Water Reactor

Total
1,190

Equivalent to emissions from 45 MWe coal-fired
plant for a year.

14

CO

29.6

Particulates

1,154

Other gases
F

0.67

Principally from UF6 production, enrichment, and
reprocessing. Concentration within range of
State standards and below level that has effects
on human health.

HCl

0.014

Liquids
SO –4

9.9

NO –3

25.8

Fluoride

12.9

Ca+

5.4

C1–

8.5

+

12.1

NH3

10.0

Fe

0.4

Tailings solutions (thousands of
MT)

240

Na

Solids

From enrichment, fuel fabrication, and
reprocessing steps. Components that constitute
a potential for adverse environmental effects are
present in dilute concentrations and receive
additional dilution by receiving bodies of water to
levels below permissible standards. The
constituents that require dilution and the flow of
dilution water are NH3: 600 cfs, NO3: 20 cfs,
fluoride: 70 cfs.

From mills only – no significant effluents to
environment.

91,000

Principally from mills – no significant effluents to
environment.

Effluents − Radiological (curies)
Gases (including entrainment)
Rn-222

–

Ra-226

0.02

Th-230

0.02

Uranium

0.034

Tritium (thousands)

18.1

C-14

24

Kr-85 (thousands)

400

Ru-106

0.14

I-129

1.3

I-131

0.83

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Presently under reconsideration by the
Commission.

Principally from fuel reprocessing plants.

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Environmental Considerations
Tc-99
Fission products and transuranics

Maximum Effect per Annual Fuel
Requirement or Reference Reactor Year of
Model 1,000 MWe Light Water Reactor

Total
–

Presently under consideration by the
Commission.

0.203

Liquids
Uranium and daughters

Principally from milling –included tailings liquor
and returned to ground, no effluents; therefore,
no effect on the environment.

2.1

Ra-226

0.0034

Th-230

0.0015

Th-234

0.01

Fission and activation products

From UF6 production.
From fuel fabrication plants – concentration
10 percent of 10 CFR Part 20 for total processing
26 annual fuel requirements for model light water
reactor.

5.9  10-6

Solids (buried onsite)
Other than high level (shallow)

Transuranic and high-level waste
(deep)
Effluents − Thermal (billions of
Btu)

11,300

1.1  107
4,063

9,100 Ci comes from low-level reactor wastes
and 1,500 Ci comes from reactor
decontamination and decommissioning – buried
at land burial facilities. 600 Ci comes from mills –
included in tailing returned to ground.
Approximately 60 Ci comes from conversion and
spent fuel storage. No significant effluent to the
environment.
Buried at Federal Repository.
Less than 5 percent of model 1,000 MWe light
water reactor.

Transportation (person-rem)
Exposure of workers and general
public

2.5

Occupational exposure

22.6

From reprocessing and waste management.

(a) In some cases where no entry appears, it is clear from the background documents that the matter was
addressed and that, in effect, the table should be read as if a specific zero entry had been made. However, there
are other areas that are not addressed in the table. Table S-3 does not include health effects from the effluents
described in the table, estimates of releases of radon-222 from the uranium fuel cycle, or estimates of
technetium-99 released from waste management or reprocessing activities. These issues may be the subject of
litigation in the individual licensing proceedings.
Data supporting this table are given in the Environmental Survey of the Uranium Fuel Cycle, WASH-1248,
April 1974; the Environmental Survey of the Reprocessing and Waste Management Portion of the LWR Fuel
Cycle,’ NUREG-0116 (Supp. 1 to WASH–1248); the Public Comments and Task Force Responses Regarding
the Environmental Survey of the Reprocessing and Waste Management Portions of the LWR Fuel Cycle,
NUREG-0216 (Supp. 2 to WASH-1248); and in the record of the final rulemaking pertaining to Uranium Fuel
Cycle Impacts from Spent Fuel Reprocessing and Radioactive Waste Management, Docket RM-50-3. The
contributions from reprocessing, waste management, and transportation of wastes are maximized for either of
the two fuel cycles (uranium only and no recycle). The contribution from transportation excludes transportation of

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cold fuel to a reactor and transportation of irradiated fuel and radioactive wastes from a reactor, which are
considered in Table S-4 of Section 51.20(g) [sic, Table S-4 now appears in Section 51.52(c)]. The contributions
from the other steps of the fuel cycle are given in columns A−E of Table S-3A of WASH-1248.
(b) The contributions to temporarily committed land from reprocessing are not prorated over 30 years, because the
complete temporary impact accrues regardless of whether the plant services 1 reactor for 1 year or 57 reactors
for 30 years.
(c) Estimated effluents based upon combustion of equivalent coal for power generation.
(d) 1.2 percent from natural gas use and process.
Source: 10 CFR 51.51.

4.14.1.3

Consideration of Environmental Justice

As stated in the NRC’s Policy Statement on the Treatment of Environmental Justice Matters in
NRC Regulatory and Licensing Actions (69 FR 52040),
An NRC EJ [environmental justice] analysis should be limited to the impacts
associated with the proposed action (i.e., the communities in the vicinity of the
proposed action). EJ-related issues differ from site to site and normally cannot be
resolved generically. Consequently, EJ, as well as other socioeconomic issues,
are normally considered in site-specific EISs. Thus, due to the site-specific
nature of an EJ analysis, EJ-related issues are usually not considered during the
preparation of a generic or programmatic EIS. EJ assessments would be
performed as necessary in the underlying licensing action for each particular
facility.
The environmental impacts of various individual operating uranium fuel cycle facilities are
addressed in separate site-specific environmental reviews and NEPA documents prepared by
the NRC. These documents include analyses that address human health and environmental
impacts on minority populations, low-income populations, and Indian Tribes. Electronic copies of
these NEPA documents are available through the NRC’s public website under Publications
Prepared by NRC Staff document collection of the NRC’s Electronic Reading Room at
http://www.nrc.gov/reading-rm/doc-collections/; and the NRC’s Agencywide Documents Access
and Management System (ADAMS) at http://www.nrc.gov/reading-rm/adams.html.
4.14.1.4

Transportation Impacts

The impacts associated with transporting fresh fuel to one 1,000 MWe model LWR and with
transporting spent fuel and radioactive waste (LLW and mixed waste) from that LWR are
provided in Table S-4 in 10 CFR 51.52. Similar to Table S-3 (Table 4.14-1), and as indicated in
10 CFR 51.52, every environmental report prepared for the construction permit stage of a
commercial nuclear power plant must contain a statement concerning the transportation of fuel
and radioactive waste to and from the reactor. A similar statement is also required in license
renewal (initial LR and SLR) applications. Table S-4 forms the basis of such a statement and is
presented here as Table 4.14-2.
A discussion of the values included in Table S-4 of 10 CFR 51.52 (see Table 4.14-2) and how
they may change during the license renewal term was included in Section 6.3 of the
1996 LR GEIS (NRC 1996). However, after the 1996 LR GEIS was issued and during the
rulemaking process for codifying Table B-1 in 10 CFR Part 51, a number of comments were
received from the public that raised some questions about the adequacy of Table 4.14-2 values
for license renewal application reviews. As a result, the NRC reevaluated the transportation
issues and the adequacy of Table 4.14-2 values for license renewal (initial LR or SLR)
application reviews. In 1999, the NRC issued an addendum to the 1996 LR GEIS (NRC 1999b)

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in which the agency evaluated the applicability of Table S-4 (Table 4.14-2) to future license
renewal proceedings, given that the spent fuel is likely to be shipped to a single repository (as
opposed to several destinations, as originally assumed in the preparation of Table S-4), and
given that shipments of spent fuel are likely to involve more highly enriched fresh fuel (more
than 4 percent as assumed in Table S-4) and higher-burnup spent fuel (higher than
33,000 MWd/MTU as assumed in Table 4.14-2). In the addendum, the NRC evaluated the
impacts of transporting the spent fuel from reactor sites to the proposed geologic repository at
Yucca Mountain in Nevada, and the impacts of shipping more highly enriched fresh fuel and
higher burnup spent fuel. Based on the evaluations, the NRC concluded that the values given in
Table 4.14-2 (Table S-4 in 10 CFR 51.52) below would still be bounding, as long as the
(1) enrichment of the fresh fuel was 5 percent or less, (2) burnup of the spent fuel was
62,000 MWd/MTU or less, and (3) higher-burnup spent fuel (higher than 33,000 MWd/MTU)
was cooled for at least 5 years before being shipped offsite. The conditions evaluated in
Addendum 1 have not changed, and no new conditions have been introduced that would alter
the conclusions in Addendum 1 (NRC 1999a). A later study found that the impacts from the
transportation of spent nuclear fuel with up to 75,000 MWd/MTU burnup would not have
significant adverse environmental impacts, provided that the impacts are not significantly
affected by fission gas releases and the fuel is cooled for at least 5 years before shipment
(Ramsdell et al. 2001).
Table 4.14-2 Table S-4 Taken from 10 CFR 51.52 on the Environmental Impact of
Transporting Fuel and Waste to and from One Light Water-Cooled Nuclear
Power Reactor(a)
Normal Conditions of Transport

Environmental Impact

Heat (per irradiated fuel cask in transit)

250,000 Btu/hr

Weight (governed by Federal or State restrictions)

73,000 lb per truck; 100 tons per cask per rail car

Traffic density:
Truck

Less than 1 per day

Rail

Less than 3 per month

Exposed Population

Estimated No. of
Persons Exposed

Transportation workers

Range of Doses to
Exposed Individuals(b)
(per reactor year)

Cumulative Dose to
Exposed Population
(per reactor year)(c)

200

0.01 to 300 millirem

4 person-rem

Onlookers

1,100

0.003 to 1.3 millirem

3 person-rem

Along route

600,000

General public:

0.0001 to 0.06 millirem

Accidents in Transport
Types of Effects

Environmental Risk

Radiological effects

Small(d)

Common (nonradiological) causes

1 fatal injury in 100 reactor years; 1 nonfatal injury
in 10 reactor years; $475 property damage per
reactor year

(a) Data supporting this table are given in the Commission’s Environmental Survey of Transportation of Radioactive
Materials to and from Nuclear Power Plants, WASH-1238, December 1972, and Supp. 1, NUREG-75/038,
April 1975. Both documents are available for inspection and copying at the Commission's Public Document
Room, One White Flint North, 11555 Rockville Pike (first floor), Rockville, Maryland 20852 and may be obtained
from National Technical Information Service, Springfield, VA 22161.

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(b) The Federal Radiation Council has recommended that the radiation doses from all sources of radiation other
than natural background and medical exposures should be limited to 5,000 millirem per year for individuals as a
result of occupational exposure and should be limited to 500 millirem per year for individuals in the general
population. The dose to individuals due to average natural background radiation is about 130 millirem per year.
(c) Man-rem is an expression for the summation of whole body doses to individuals in a group. Thus, if each
member of a population group of 1,000 people received a dose of 0.001 rem (1 millirem), or if 2 people received
a dose of 0.5 rem (500 millirem) each, the total man-rem dose in each case would be 1 man-rem.
(d) Although the environmental risk of radiological effects stemming from transportation accidents is currently
incapable of being numerically quantified, the risk remains small, regardless of whether it is being applied to a
single reactor or a multi-reactor site.
Source: 10 CFR 51.52.

4.14.1.4.1 Consideration of Environmental Justice (Transportation)
The human health effects of transporting spent nuclear fuel were originally addressed in an
addendum to the 1996 LR GEIS (NRC 1999b), in which the agency evaluated the applicability
of Table S-4 to future license renewal proceedings given that spent fuel is likely to be shipped to
a single geologic repository. As part of the site characterization and recommendation process
for the proposed geologic repository at Yucca Mountain, Nevada, the DOE is required by the
Nuclear Waste Policy Act of 1982 to prepare an EIS. By law, the NRC is required to adopt
DOE’s EIS, to “the extent practicable,” as part of any possible NRC construction authorization
decision. As a result, DOE prepared and submitted to NRC the Supplemental Environmental
Impact Statement for a Geologic Repository for the Disposal of Spent Nuclear Fuel and HighLevel Radioactive Waste at Yucca Mountain, Nye County, Nevada (Repository Supplemental
EIS) (DOE/EIS-0250F-S1; DOE 2008). This document includes analyses that address the
human health and environmental impacts on minority populations, low-income populations, and
Indian Tribes.
As noted in DOE’s Repository Supplemental EIS, shipments of spent nuclear fuel (as well as
fresh fuel) would use the Nation’s existing railroads and highways (DOE 2008). Consequently,
DOE estimates that transportation-related environmental impacts affecting land use; air quality;
hydrology; biological resources and soils; cultural resources; socioeconomics; noise and
vibration; aesthetic resources; utilities, energy, and materials; and waste management would be
SMALL. Nonetheless, segments of the population, including minority populations, low-income
populations, and Indian Tribes, would likely experience some transportation-related
environmental effects.
The DOE did not identify any high and adverse human health or environmental impacts on
members of the public from the transport of spent nuclear fuel, and determined that subsections
of the population, including minority populations, low-income populations, and Indian Tribes,
would not experience disproportionate effects. In addition, DOE did not identify any unique
patterns of subsistence consumption, exposure pathways, sensitivities, or cultural practices that
would expose these populations to disproportionately high and adverse effects. Consequently,
DOE concluded that minority populations, low-income populations, and Indian Tribes would not
experience any disproportionately high and adverse human health or environmental effects from
the transportation of spent nuclear fuel to Yucca Mountain (DOE 2008). On September 8, 2008,
the NRC staff recommended the Commission adopt DOE’s Repository Supplemental EIS with
supplements (73 FR 53284).
As discussed in Section 4.11.1.3, the NRC prepared and issued an EIS supplement in 2016
(NUREG-2184; NRC 2016a) that evaluated environmental impacts due to potential radiological
releases from the proposed Yucca Mountain geologic repository. The supplement did not
evaluate transportation impacts. The NRC determined that there would be no disproportionately

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high and adverse human health or environmental effects from the use or discharge of
groundwater flowing from the repository on minority or low-income populations.
In light of DOE’s decision to not proceed with the Yucca Mountain nuclear waste geologic
repository and comprehensive reevaluation of policies for managing spent nuclear fuel from
nuclear power plants (see Section 4.11.1.3), some or all of the environmental impact analyses
in DOE’s Repository Supplemental EIS will have to be revisited. Nevertheless, as reaffirmed by
the NRC in the 2014 Continued Storage Final Rule (79 FR 56238) and as supported by the
analyses in NUREG-2157, disposal in a geologic repository continues to be technically feasible.
International progress in the development of repositories provides confidence that it is likely that
a repository can and will be developed in the United States, with 25 to 35 years being a
reasonable period for repository development. The NRC expects that DOE’s analysis for the
Yucca Mountain geologic repository would be representative of any future repository.
4.14.1.5

Environmental Impact Issues of the Uranium Fuel Cycle

Nuclear fuel is needed for the operation of light water reactors during the license renewal term
(initial LR or SLR) in the same way that it is needed during the current license period. Therefore,
the factors that affect the data presented in Tables S-3 (Table 4.14-1) and S-4 (Table 4.14-2) of
10 CFR 51.51 and 51.52, respectively, do not change whether a light water reactor is operating
under its original license or a renewed license. In the 1996 LR GEIS, there are nine issues that
relate to uranium fuel cycle and waste management; five of them that relate to waste
management are addressed in Section 4.11.1.
The remaining four impact issues include the following (as evaluated in the 2013 LR GEIS
[NRC 2013a]):
• offsite radiological impacts – individual impacts from other than the disposal of spent fuel and
high-level waste
• offsite radiological impacts – collective impacts from other than the disposal of spent fuel and
high-level waste)
• nonradiological impacts of the uranium fuel cycle
• transportation
Offsite Radiological Impacts – Individual Impacts from Other than the Disposal of Spent
Fuel and High-Level Waste
This issue addresses the radiological impacts on individuals who live near uranium fuel cycle
facilities. The primary indicators of impact are the concentrations of radionuclides in the
effluents from the fuel cycle facilities and the radiological doses received by an MEI (a
maximally exposed individual) on the site boundary or at some location away from the site
boundary. As discussed in Section 3.9.1 of this LR GEIS, an MEI can be exposed to radiation
from radionuclides found in the effluents of nuclear fuel cycle facilities and from radiation “shine”
from buildings, storage facilities, and storage tanks containing radioactive material. The basis
for establishing the significance of individual effects is the comparison of the releases in the
effluents and the MEI doses with the permissible levels in applicable regulations. The analyses
performed by the NRC in the preparation of Table 4.14-1 and found in the 1996 LR GEIS
indicate that as long as the facilities operate under a valid license issued by either the NRC or
an agreement State, the individual effects will meet the applicable regulations. Based on these
considerations, the NRC has concluded that the impacts on individuals from radioactive

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gaseous and liquid releases during the initial LR or SLR term would remain at or below the
NRC’s regulatory limits. Accordingly, the NRC concludes that offsite radiological impacts of the
uranium fuel cycle (individual effects from sources other than the disposal of spent fuel and
high-level waste) are SMALL. The efforts to keep the releases and doses ALARA will continue
to apply to fuel-cycle-related activities. This was considered a Category 1 issue in the
2013 LR GEIS. The staff reviewed information from SEISs (for initial LRs and SLRs) completed
since development of the 2013 LR GEIS and identified no new information or situations that
would result in different impacts for this issue for either an initial LR or SLR term. Therefore, this
is a Category 1 issue.
Offsite Radiological Impacts – Collective Impacts from Other than the Disposal of Spent
Fuel and High-Level Waste
The focus of this issue is the collective radiological doses to and health impacts on the general
public resulting from uranium fuel cycle facilities over the license renewal term. The radiological
doses received by the general public are calculated based on releases from the facilities to the
environment, as provided in Table 4.14-1. These estimates were provided in the 1996 LR GEIS
(NRC 1996) for the gaseous and liquid releases listed in Table S-3 as well as for radon-222 and
technetium-99 releases (Rn-222 and Tc-99), which are not listed in Table 4.14-1. The
population dose commitments were normalized for each year of operation of the model
1,000 MWe LWR (reference reactor year).
Based on the analyses provided in the 1996 LR GEIS and reexamined and discussed in the
2013 LR GEIS, the estimated involuntary 100-year dose commitment to the U.S. population
resulting from the radioactive gaseous releases from uranium fuel cycle facilities (excluding the
reactors and releases of Rn-222 and Tc-99) was estimated to be 400 person-rem
(4 person-sievert [Sv]) for 1 reference reactor year. Similarly, the environmental dose
commitment to the U.S. population from the liquid releases was estimated to be 200 person-rem
(2 person-Sv) per reference reactor year. As a result, the total estimated involuntary 100-year
dose commitment to the U.S. population from radioactive gaseous and liquid releases listed in
Table 4.14-1 was given as 600 person-rem (6 person-Sv) per reference reactor year (see
Section 6.2.2 of the 1996 LR GEIS (NRC 1996).
The 1996 and 2013 LR GEISs also provided a detailed analysis of potential doses to the U.S.
population from Rn-222 releases, which primarily occur during mining and milling operations
and as emissions from mill tailings, and Tc-99 releases, which primarily occur during the
enrichment process (Section 6.2.2 of the 1996 LR GEIS (NRC 1996). Tc-99 releases during
enrichment occurred through a gaseous diffusions process that is no longer used within the
United States. Tc-99 is not released through centrifuge enrichment processes and is not
reconsidered in this analysis. The U.S. population doses resulting from the Rn-222 releases for
1 reference reactor year are summarized in Table 4.14-3 from the 2013 LR GEIS. The total
population dose from all releases to the environment, including the Rn-222, is given as
838.6 person-rem (8.386 person-Sv) per reference reactor year.
As discussed in the 1996 LR GEIS and as confirmed in the 2013 LR GEIS, the dose estimates
given above were based on highly conservative assumptions. In actuality, the doses received by
most members of the public would be so small that they would be indistinguishable from the
variations in natural background radiation. There are no regulatory limits applicable to collective
doses to the general public from fuel cycle facilities. All regulatory limits are based on individual
doses. All fuel cycle facilities are designed and operated to meet the applicable regulatory limits.

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Table 4.14-3 Population Doses from Uranium Fuel Cycle Facilities Normalized to One
Reference Reactor Year
Collective Dose (person-rem)(a)

Source
Gaseous releases
Liquid releases
Rn-222 releases from uranium mining and milling
Rn-222 releases from unreclaimed open-pit mines
Rn-222 releases from stabilized tailings piles
Total

400
200
140
96
2.6
838.6

Rn-222 = Radon-222.
(a) To convert person-rem to person-Sv, multiply by 0.01.
Source: Modified from NRC 1996.

As discussed in the 1996 LR GEIS and as confirmed in the 2013 LR GEIS, despite the lack of
definitive data, some judgment as to the regulatory NEPA implications of these matters should
be made and it makes no sense to repeat the same judgment in every case. The Commission
concludes that these impacts are acceptable in that these impacts would not be sufficiently
large to require the NEPA conclusion, for any plant, that the option of extended operation under
10 CFR Part 54 should be eliminated. Accordingly, while the Commission has not assigned a
single level of significance for the collective effects of the fuel cycle; this issue was considered
Category 1. The staff reviewed information from SEISs (for initial LRs and SLRs) completed
since development of the 2013 LR GEIS and identified no new information or situations that
would result in different impacts for this issue for either an initial LR or SLR term. This is a
Category 1 issue.
Nonradiological Impacts of the Uranium Fuel Cycle
This section addresses the nonradiological impacts associated with the uranium fuel cycle
facilities as they relate to license renewal. Data on the nonradiological impacts of the fuel cycle
are provided in Table 4.14-1. These data cover land use, water use, fossil fuel use, and
chemical effluents. The significance of the environmental impacts associated with these data
was evaluated in the 1996 LR GEIS based on several relative comparisons. The land
requirements were compared to those for a coal-fired power plant that could be built to replace
the nuclear capacity if the operating license is not renewed. Water requirements for the uranium
fuel cycle were compared to the annual requirements for a nuclear power plant. The amount of
fossil fuel (coal and natural gas) consumed to produce electrical energy and process heat
during the various phases of the uranium fuel cycle was compared to the amount of fossil fuel
that would have been used if the electrical output from the nuclear plant were supplied by a
coal-fired plant. Similarly, the gaseous effluents SO2, NO, hydrocarbons, CO, and other PM
released as a consequence of the coal-fired electrical energy used in the uranium fuel cycle
were compared with equivalent quantities of the same effluents that would be released from a
45 MWe coal-fired plant. It was noted that the impacts associated with uses of all of the above
resources would be SMALL. Any impacts associated with nonradiological liquid releases from
the fuel cycle facilities would also be SMALL. As a result, the aggregate nonradiological impacts
of the uranium fuel cycle resulting from the renewal (initial LR or SLR) of an operating license
for a plant would be SMALL, and it was considered a Category 1 issue in the 2013 LR GEIS.
The staff reviewed information from SEISs (for initial LRs and SLRs) completed since
development of the 2013 LR GEIS and identified no new information or situations that would
result in different impacts for this issue for either an initial LR or SLR term. Thus, this is a
Category 1 issue.

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Transportation
This section addresses the impacts associated with transportation of fuel and waste to and from
one light water reactor during the license renewal term (initial LR and SLR). Table S-4
(Table 4.14-2) in 10 CFR 51.52 forms the basis for analysis of these impacts when evaluating
the applications for license renewal (initial LR and SLR) from owners of light water reactors. As
discussed previously in this section, the applicability of Table 4.14-2 for license renewal
(initial LR and SLR) applications was extensively studied in the 1996 LR GEIS and its
Addendum 1 (NRC 1999b) and confirmed in the 2013 LR GEIS. The impacts were found to be
SMALL, and the findings were stated as follows:
The impacts of transporting spent fuel enriched up to 5 percent uranium-235 with
average burnup for the peak rod to current levels approved by NRC up to
62,000 MWd/MTU and the cumulative impacts of transporting high-level waste to
a single repository, such as Yucca Mountain, Nevada are found to be consistent
with the impact values contained in 10 CFR 51.52(c), Summary Table S-4,
“Environmental Impact of Transportation of Fuel and Waste to and from One
Light-Water-Cooled Nuclear Power Reactor.” If fuel enrichment or burnup
conditions are not met, the applicant must submit an assessment of the
implications for the environmental impact values reported in 10 CFR 51.52.
The issue was designated as Category 1. The staff reviewed information from SEISs (for
initial LRs and SLRs) completed since development of the 2013 LR GEIS and identified no new
information or situations that would result in different impacts from what was concluded in the
2013 LR GEIS for this issue for either an initial LR or SLR term. This is a Category 1 issue.
4.14.2

Environmental Consequences of Terminating Operations and Decommissioning

The following sections briefly summarize the environmental impacts of license renewal on
terminating reactor operations and the decommissioning of nuclear power plants. For the
proposed action, license renewal would delay this eventuality for up to an additional 20 years.
4.14.2.1

Termination of Nuclear Power Plant Operations and Decommissioning

This section describes the environmental consequences of terminating reactor operations and
decommissioning nuclear power plants. Impacts attributable to the proposed action (license
renewal) would be the incremental environmental effects from an additional 20 years of nuclear
power plant operations and refurbishment on decommissioning. The impacts from
decommissioning a nuclear power plant are evaluated in the Decommissioning GEIS
(NRC 2002c).
Most nuclear plant activities and systems dedicated to reactor operations would cease after
reactor shutdown. Some activities (e.g., security and spent nuclear fuel management) would
continue, while other activities (administration, laboratory analysis, and reactor surveillance,
monitoring, and maintenance) may be reduced or eliminated. Shared systems at a nuclear
power plant with multiple units, would continue to operate but at reduced capacity until all units
cease operation. The cessation of activities needed to maintain and operate the reactor would
reduce the need for workers at the nuclear power plant, but would not lead to the immediate
dismantlement of the reactor or its infrastructure.

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The decommissioning process begins when the licensee informs the NRC that it has
permanently ceased reactor operation, defueled, and intends to decommission the nuclear
plant. The licensee may notify the NRC of the permanent cessation of reactor operations prior to
the end of the license term while still operating. Regulations in 10 CFR 50.82(a)(4)(i) require
operating reactor licensees to submit a post-shutdown decommissioning activities report
(PSDAR) to the NRC, with a copy forwarded to the affected State(s), no later than 2 years after
the cessation of reactor operations.
The licensee must describe all planned activities in the PSDAR, including the schedule and
estimated costs for radiological decommissioning (excluding site restoration and spent fuel
management costs). The licensee also documents the evaluation of the environmental impacts
of planned decommissioning activities at the nuclear plant, providing a basis for why impacts
are bounded by previously issued environmental review documents (e.g., Decommissioning
GEIS; NRC 2002c). The licensee must also describe any decommissioning activities whose
impacts are not bounded and how the impacts will be addressed prior to conducting these
activities at the nuclear plant (e.g., through regulatory exemption or license amendment
requests). The licensee is required to update the PSDAR if there are any significant changes in
decommissioning activity, costs, schedule, or environmental impact.
Once the NRC receives the PSDAR, the report will be docketed, and a notice of receipt will be
published in the Federal Register to solicit public comments. The NRC conducts a public
meeting near the nuclear plant to discuss the licensee’s decommissioning plans and schedule,
answer questions, and solicit comments.
The licensee submits a License Termination Plan with final status survey strategy to the NRC
near the end of decommissioning, at least 2 years before the operating license can be
terminated. Prior to completing decommissioning, the licensee must conduct a survey
demonstrating compliance with site release criteria established in the License Termination Plan.
The NRC verifies the survey results by one or more of the following: a quality assurance/quality
control review, side-by-side or split sampling of radiological surveys of selected areas, and
independent confirmatory surveys. When the NRC confirms that the criteria in the License
Termination Plan and all other NRC regulatory requirements have been met, the NRC either
terminates or amends the operating license, depending on the licensee’s decision to use the
licensed area. The nuclear plant and any remaining structures on the site can then be released
for restricted or unrestricted use. The criteria for restricted use conditions and alternate criteria
that the NRC may approve under certain conditions are listed in 10 CFR 20.1403 and
10 CFR 20.1404, respectively. The radiological criteria for releasing sites for unrestricted use
are given in 10 CFR 20.1402.
Three decommissioning options are evaluated in the Decommissioning GEIS (NRC 2002c):
DECON, SAFSTOR, and ENTOMB. In the DECON option, equipment, structures, and portions
of a nuclear plant containing radioactive contaminants are removed and safely buried in a LLW
landfill or are decontaminated to a level that permits the property to be released for unrestricted
use shortly after the cessation of reactor operations. In the SAFSTOR option, the facility is
maintained in such condition that the nuclear plant can be safely stored and subsequently
decontaminated later to levels that permit the property to be released for restricted or
unrestricted use. In the ENTOMB option, radioactive contaminants are encased in a structurally
long-lived material, such as concrete. The entombment structure is maintained and surveillance
is carried out until the radioactivity decays to a level permitting unrestricted release of the
property.

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The following sections discuss the potential environmental effects of license renewal on
terminating reactor operations and decommissioning.
4.14.2.1.1 Land Use
Land use activities after terminating reactor operations and during decommissioning would be
comparable to what was experienced during construction and would not require land outside the
developed areas of the site. Activities requiring land include equipment and large component
laydown areas. Temporary changes in onsite land use would not affect the industrial use of the
site.
4.14.2.1.2 Visual Resources
The termination of reactor operations would not change the visual appearance of the nuclear
plant. The most notable change, however, would be the elimination of condensate plumes from
cooling towers. License renewal would only delay decommissioning, prolonging the visual
impact. The delay would have no new or added visual impact.
4.14.2.1.3 Air Quality
After the termination of reactor operations, air emissions from the nuclear power plant would
continue, but at reduced levels. Natural or mechanical draft cooling tower drift would also be
greatly reduced or eliminated. Air emissions from boilers and emergency diesel generators
would continue until the decommissioning of the nuclear plant has been completed.
4.14.2.1.4 Noise
During decommissioning, noise would generally be far enough away from sensitive receptors
outside nuclear plant boundaries, attenuated to nearly ambient levels, and scarcely noticeable
offsite. However, during the demolition, offsite noise levels could be loud enough that activities
may need to be curtailed during early morning and evening hours. Noise abatement procedures
could also be used during decommissioning to reduce noise.
4.14.2.1.5 Geology and Soils
Termination of reactor operations and decommissioning are not expected to affect geology and
soils. The demolition and removal of buildings, foundation slabs, parking lots, and roads would
expose soil to possible erosion. Geologic resources in the form of gravel or crushed stone may
be needed to construct temporary roads for heavy equipment.
4.14.2.1.6 Water Resources – Surface Water and Groundwater
After the termination of reactor operations, water use would be dramatically reduced; however,
water demands would continue for the service water system to support activities such as
temperature control of the spent fuel pool and other miscellaneous industrial maintenance
applications. Surface water or groundwater intake and consumptive use would be very low
compared to use during the operational phase. Discharge of liquid wastes and biocides would
also be proportionately reduced.

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Because the site workforce would be reduced, the volume of sanitary sewage effluent would be
less than that during reactor operations. Pumping rates for groundwater used for potable water
systems would also decrease because of the reduced workforce.
Hydrology and water quality impacts from soil erosion and storm events are expected to be
unchanged. Erosion would be mitigated as part of general site maintenance during
decommissioning.
4.14.2.1.7 Ecological Resources
Termination of reactor operations would reduce some ecological resource impacts and eliminate
others. Nuclear plant structures including cooling towers and transmission lines would continue
to be collision hazards for birds. The impingement and entrainment of aquatic organisms would
decrease after reactor operations cease, and the potential for impacts on aquatic communities
would be reduced. In general, the termination of entrainment and impingement would have
positive effects on affected organisms. Because significantly smaller volumes of heated water
would be discharged after reactor operations cease, the nuclear plant’s influence on the thermal
conditions in the receiving waters would be greatly reduced.
Aquatic communities and organisms acclimated to warmer temperatures and biocides may have
developed within the nuclear plant discharge mixing zone during years of reactor operation
because of the warmer environment. These organisms would be adversely affected as the
water temperature cooled and the original environmental conditions were restored within the
body of water. Organisms susceptible to cold shock would be affected. Such effects, which
normally occur during winter months, would occur after the reactor ceases operations.
Cooling ponds maintained during reactor operations by pumping water from another waterbody
would likely revert to a terrestrial system after the termination of reactor operations and pumping
stops and thermal effects on them cease. Cessation of the heated effluent would change the
composition and dynamics of the pond community until it resembled that of other ponds in the
region not used for cooling.
Dredging would no longer be needed in the vicinity of cooling water structures, thereby
eliminating the effect on aquatic biota. The potential for gas supersaturation and its effect on
biota would also be eliminated or decreased.
There is the potential for some effects on aquatic resources to continue regardless of whether
the reactor is operating. Dams and reservoirs constructed to supply water may continue to
prevent migration of anadromous fish unless these structures are removed.
The termination of reactor operations could have a beneficial impact on the Federally listed
loggerhead sea turtle (threatened), green sea turtle (Chelonia mydas, threatened), leatherback
sea turtle (endangered), hawksbill sea turtle (endangered), and Kemp’s ridley sea turtle
(endangered), which have been impinged at several nuclear power plants (e.g., St. Lucie and
Oyster Creek). Similarly, potential benefits to the Federally endangered West Indian manatee
and pinnipeds, protected under the Marine Mammal Protection Act, could occur. For example,
the West Indian manatee has been impinged at St. Lucie, and incidental takes of harbor seals,
gray seals, harp seals, and hooded seals occur at the Seabrook plant. Elimination of
high-temperature discharges at nuclear plants in Florida may reduce habitat suitability for the
West Indian manatee, particularly during winter. However, the West Indian manatee occupies
other habitats in Florida that do not have artificially elevated temperatures, and it uses a number

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of thermal discharges from fossil fuel plants along both coasts of Florida (Laist and Reynolds
2005). Potential impingement and entrainment losses of special status fish species could also
decrease.
The overall impact on ecological resources depends on the decommissioning activity. The
greatest potential decommissioning impact on protected species is associated with the
dismantlement of the nuclear plant, including intake and discharge structures. Many activities
that could affect ecological resources during decommissioning are the same activities that occur
during reactor operation. Continued reactor operations during initial LR and SLR terms will not
change the level of impact during decommissioning.
4.14.2.1.8 Historic and Cultural Resources
The termination of reactor operations would not affect historic or cultural resources at a nuclear
power plant. The continued reactor operations at a nuclear plant under a renewed license
(i.e., initial LR or SLR) would not alter this conclusion. Most historic and cultural resource
impacts occurred during construction of the nuclear power plant. Continued operations and
maintenance activities have the potential to affect these resources, as discussed in
Section 4.7.1. There is nothing inherent in operating a nuclear plant for a longer time period that
would increase or decrease the impact on these resources from decommissioning. Delaying
decommissioning is not expected to have any effect on historic and cultural resources within a
transmission line ROW.
4.14.2.1.9 Socioeconomics
Terminating reactor operations could have a noticeable impact on socioeconomic conditions in
the region around the nuclear plant. There would be immediate socioeconomic impacts from the
loss of jobs (some, though not all, employees would begin to leave after reactor shutdown); and
tax revenues generated by plant operations would also be reduced. Depending on the tax
formula used to determine property tax payments, the amount of money paid to local taxing
jurisdictions may be reduced. However, property tax payments would continue. Demand for
services and housing would likely decline. Indirect employment and income created as a result
of nuclear power plant operations would also be reduced.
Loss of employment at nuclear plants in rural communities would likely mean workers and their
families would leave in search of jobs elsewhere. The decrease in the demand for housing and
the increase in available housing would depress rural housing market prices. Conversely, in
urban areas, nuclear plant workers and their families may remain because there are greater
opportunities for reemployment.
Traffic congestion caused by commuting workers and truck deliveries during plant operations
would also be reduced.
4.14.2.1.10 Human Health
After the termination of reactor operations, there is a period of time before the decommissioning
of the nuclear plant begins—ranging from months to years. During this time, the reactor would
be placed in a cold shutdown condition and maintained. Workers would continue to be exposed
to radiation. Radioactive gaseous and liquid effluent releases to the environment would
continue, although at lower levels. The radiological impacts on workers and members of the
public during decommissioning would be less than those during reactor operations.

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4.14.2.1.11 Radiological Exposure
During decommissioning activities, workers and members of the public would be exposed to
radioactive materials released to the environment. Regulatory requirements and dose limits
during decommissioning are the same as when reactors are operating (see Section 3.9.1.1).
Many decommissioning activities are similar to those that occur during reactor operations
including maintenance outages (e.g., decontamination of piping and surfaces; removal of piping,
pumps, and valves; and removal of heat exchangers). Some activities, such as removal of the
reactor vessel or demolition of facilities, are unique to decommissioning. Doses to the public
would be well below applicable regulatory standards, regardless of which decommissioning
option is chosen.
4.14.2.1.12 Chemical Hazards
Decommissioning involves many activities that expose workers to chemical hazards, including
paints, asbestos, lead, polychlorobiphenyls, mercury, quartz, and other hazardous materials in
building materials. A delay in terminating reactor operations and decommissioning would not
change the projected human health impact from chemical hazards because there would not be
any more hazardous chemicals present.
4.14.2.1.13 Microbiological Hazards
During decommissioning, workers may be exposed to molds and other biological organisms.
License renewal (initial LR and SLR) would not change the microbiological hazard during
decommissioning because workers would be practicing good industrial hygiene and using
personal protective equipment when biological hazards were identified.
4.14.2.1.14 Electromagnetic Fields
After the termination of reactor operations, electricity is no longer being generated. Power would
still be provided to the nuclear plant, and workers might be exposed to EMFs during
decommissioning. The EMF impact during decommissioning would be unaffected by license
renewal.
4.14.2.1.15 Accidents During Termination of Reactor Operations and Decommissioning
The impacts of postulated accidents during the license renewal term are discussed in
Section 4.9.1.2. General characteristics and consequences of postulated accidents, including
source term, are expected to be similar after reactor shutdown. Because of aging management
activities and the extended life of certain systems, structures, and components, there may be
small differences in the probabilities of occurrence of these accidents after reactor shutdown.
These differences, however, are not expected to be significant, and the risks of accidents after
reactor shutdown would generally be less than the risks discussed in Section 4.9.1.2.
The impacts associated with accidents during the decontamination and decommissioning of
nuclear power plants are analyzed in the Decommissioning GEIS (NRC 2002c). Radiological
accidents considered in the analysis included onsite storage and handling of spent nuclear fuel
and decontamination, dismantlement, and storage accidents. Accidents included fires, handling
accidents, explosions (e.g., explosion of liquid propane gas tanks), and accidental releases of
liquid radioactive wastes from storage tanks.

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License renewal would merely delay when accidents associated with the termination of reactor
operations and decommissioning could occur and would not significantly affect their probability
or consequence.
4.14.2.1.16 Environmental Justice
Termination of reactor operations and the resulting loss of jobs, income, and tax revenue could
disproportionately affect minority and low-income populations and Indian Tribes. The loss of tax
revenue, for example, could reduce the availability or eliminate some of the community services
that low-income and minority populations may depend on. This situation could be offset with the
construction and operation of replacement power generating facilities and the creation of other
employment opportunities at or near the nuclear plant site.
Decontamination and decommissioning activities could affect air and water quality in the area
around each nuclear plant site. This could cause health and other environmental effects in
minority populations, low-income populations, or Indian Tribes, if present. Populations with
resource dependencies or practices (e.g., subsistence agriculture, hunting, fishing) could be
disproportionately affected. License renewal would only delay, but not alter, the impact of
decommissioning on minority and low-income populations around each nuclear plant.
4.14.2.1.17 Waste Management and Pollution Prevention
After terminating operations, the reactor is placed in a cold shutdown condition and maintained
prior to active decommissioning. The types of waste generated after reactor shutdown would be
the same as those generated during operations. However, the volume of waste generated each
day may be less than that generated during reactor operations.
Pollution prevention and waste minimization measures would likely continue. As discussed in
Section 4.11.1.2, spent nuclear fuel can be safely stored onsite with minimal environmental
impact during the license renewal term. The NRC’s Generic Environmental Impact Statement
for Continued Storage of Spent Nuclear Fuel (NUREG-2157; NRC 2014c) addresses the
environmental impacts of spent nuclear fuel storage after the termination of reactor operations.
Wastes generated after the termination of reactor operations and during decommissioning
would be shipped offsite for treatment and disposal. Of the three decommissioning options,
DECON would generate the most waste. In SAFSTOR or ENTOMB, contaminated materials
remain onsite temporarily or permanently, respectively.
The types of wastes generated during decommissioning include LLW, mixed waste, hazardous
waste, and nonradioactive, nonhazardous waste (see Section 3.11 for waste type definitions).
No spent nuclear fuel, HLW, or transuranic waste would be generated after the termination of
reactor operations and during decommissioning because any remaining fuel in the reactor
would have been moved to either the spent fuel pool or an ISFSI.
Most of the waste generated during decommissioning would be LLW and nonradioactive,
nonhazardous waste. Small quantities of mixed waste would be managed per RCRA and the
Atomic Energy Act. Hazardous waste would mainly consist of paints, solvents, and batteries.
Materials used to decontaminate surfaces could be classified as mixed waste. Mixed and
hazardous wastes could be treated prior to being sent to a disposal facility. Nonradioactive,
nonhazardous waste, mostly concrete rubble and debris, would be sent to a local landfill.

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The volume of waste generated during decommissioning may be greater because of license
renewal. Waste accumulated at the nuclear plant, and the radioactivity of some components
undergoing decommissioning might be slightly higher after the license renewal term. Material
near the core of the reactor may have slightly higher radioactivity because of the additional
years of reactor operation due to the buildup in long-lived radionuclides. This situation would
mainly affect the amount of greater-than-Class C LLW at the site. There would also be more
spent fuel generated because of license renewal.
The impacts of license renewal on terminating reactor operations and decommissioning are
considered to be SMALL for all nuclear plants and are a Category 1 issue in the 2013 LR GEIS.
As previously noted, the impacts of decommissioning nuclear power plants are evaluated in the
Decommissioning GEIS (NRC 2002c).
Based on these considerations, the NRC concludes that impacts from continued nuclear plant
operations during initial LR and SLR terms and refurbishment on terminating reactor operations
and decommissioning would be SMALL for all nuclear plants. The staff reviewed information
from SEISs (for initial LRs and SLRs) completed since development of the 2013 LR GEIS and
identified no new information or situations that would result in different impacts for this issue for
either an initial LR or SLR term. License renewal reviews have revealed no difference in
environmental impacts whether decommissioning occurs at the end of the current operating
license or following a 20-year initial LR or SLR term. Therefore, terminating reactor operations
and decommissioning impacts would be SMALL for all nuclear plants and it is a Category 1
issue.

4.15 Resource Commitments Associated with the Proposed Action
This section addresses the resources that would be committed under the proposed action
(license renewal). In particular, it describes unavoidable adverse environmental impacts
(Section 4.15.1), the relationship between short-term uses of the environment and the
maintenance and enhancement of long-term productivity (Section 4.15.2), and the irreversible
and irretrievable commitment of resources (Section 4.15.3) that would be associated with the
proposed action. Potential unavoidable adverse environmental impacts and irreversible and
irretrievable resource commitments that would be associated with alternatives to the proposed
action are also discussed.
4.15.1

Unavoidable Adverse Environmental Impacts

Unavoidable adverse environmental impacts are impacts that would occur after implementation
of all feasible mitigation measures. Continued nuclear power plant operations and the
implementation of any of the replacement energy alternatives considered in this LR GEIS would
result in some unavoidable adverse environmental impacts.
The impacts of continued nuclear power plant operations that are anticipated to occur are
discussed for each resource (subject matter) area in Sections 4.1 through 4.12. Some of these
impacts cannot be avoided because they are inherently associated with nuclear power plant
operations and cannot be fully mitigated. Minor unavoidable adverse impacts on air quality
would occur due to emission and release of various chemical and radiological constituents into
the environment from plant operations. Nonradiological emissions are expected to comply with
EPA emissions standards, though the alternative of operating a fossil-fueled power plant in
some areas may worsen existing air quality attainment issues. Routine chemical and
radiological emissions would not exceed the National Emission Standards for Hazardous Air

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Pollutants. Other unavoidable adverse impacts (depending on the plant) include the impact on
land use and visual resources, some minor noise effects, surface water and groundwater use,
thermal effluents discharged to the environment from the power conversion equipment, and
entrainment and impingement of aquatic organisms in the cooling water system. Industrial
wastewater effluents and cooling water system operations would be subject to regulations
promulgated pursuant to the CWA.
During nuclear power plant operations, workers and members of the public would face
unavoidable exposure to radiation and hazardous and toxic chemicals, but releases would be
controlled and the resulting exposures would not exceed any standards or regulatory limits.
Workers would be exposed to radiation and chemicals associated with routine plant operations
and the handling of nuclear fuel and waste material. Workers would have a higher risk of
exposure than members of the public, but doses would be administratively controlled and would
not exceed any standards or administrative control limits. Construction and operation of
alternative replacement energy-generating facilities would also result in unavoidable exposure
of workers and the general public to hazardous and toxic chemicals.
Also unavoidable would be the generation of spent nuclear fuel and waste material, including
LLW, hazardous waste, and nonhazardous waste. Hazardous and nonhazardous wastes would
also be generated at non-nuclear power-generating facilities. Wastes generated during plant
operations would be collected, stored, and shipped for suitable treatment, recycling, or disposal
in accordance with applicable Federal and State regulations. Due to the costs of handling these
materials, power plant operators would be expected to conduct all activities and optimize all
operations in a way that minimizes waste generation. Although pollution prevention and waste
minimization efforts are intended to prevent emissions to the environment and prevent and/or
minimize the quantities of waste generated and disposed of, some wastes and emissions
cannot be entirely eliminated due to current technology.
Many of these unavoidable impacts are being mitigated by incorporating safety features and/or
applying operational procedures at the nuclear power plants, and are monitored by plant
personnel and regulatory agencies. Thermal, entrainment, and impingement impacts at plants
with once-through cooling water systems are unavoidable. These impacts could be reduced by
modifying the once-through cooling system or by converting to a closed-cycle cooling system.
Although closed-cycle cooling water systems can reduce thermal, entrainment, and
impingement impacts, they increase water consumption (through cooling tower evaporation),
fogging, icing, and salt drift. However, the NRC has neither the statutory nor the regulatory
authority to determine which cooling water system or technology should be used, or to decide
other environmental permitting issues.
Nuclear power plants being considered for license renewal already exist and nearly all have
been operating for several decades. The environmental impacts considered for license renewal
are those associated with continued nuclear power plant operation and refurbishment.
Replacement energy (power) and other alternatives to license renewal generally involve major
construction impacts, as described in Appendix D (Section D.4). Therefore, unavoidable
adverse impacts of a replacement energy alternative could be greater than those associated
with the continued operation of an existing nuclear power plant.
Unavoidable adverse impacts would vary among the nuclear power plants, and the scale of the
impact would depend on the specific characteristics of each power plant and its interaction with
the environment. These unavoidable adverse impacts are evaluated in plant-specific SEISs.

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4.15.2

Relationship between Short-Term Use of the Environment and Long-Term
Productivity

The operation of power-generating facilities would result in short-term uses of the environment
as described earlier in this Chapter. “Short-term” is the period of time during which continued
power-generating activities would take place.
Power plant operations would necessitate short-term use of the environment and commitments
of resources, and would also commit certain resources (e.g., land and energy) indefinitely or
permanently. Certain short-term resource commitments would be substantially greater under
most energy alternatives, including license renewal (initial LR or SLR), than under the no action
alternative, due to the continued generation of electrical power as well as continued use of
generating sites and associated infrastructure. During operations, all energy alternatives would
entail similar relationships between local short-term uses of the environment and the
maintenance and enhancement of long-term productivity.
Short-term use of the environment can affect long-term productivity of the ecosystem if the use
alters the ability of the ecosystem to reestablish an equilibrium that is comparable to that of its
original (natural) condition. An initial commitment regarding the trade-off between short-term use
and long-term productivity at a nuclear power plant was made when the nuclear plant was first
constructed. Renewal of the operating license and the continued operation of the nuclear power
plant would not alter any existing effects on long-term productivity, but they might postpone the
availability of the power plant site for other uses. The no action alternative would lead to a
cessation of operations and shutdown of the power plant (an eventuality regardless of whether
the license is renewed).
Air emissions from power plant operations would introduce small amounts of radiological and
nonradiological constituents to the region around the plant site. Over time, these emissions
could result in increased concentrations and exposure, but are not expected to affect air quality
or radiation exposure to the extent that public health and long-term productivity of the
environment would be impaired.
Continued employment, expenditures, and tax revenues generated during power plant
operations would directly benefit local, regional, and State economies over the short-term. Local
governments investing project-generated tax revenues into infrastructure and other required
services could enhance economic productivity over the long term.
The management and disposal of spent nuclear fuel, LLW, hazardous waste, and
nonhazardous waste would require an increase in energy and would consume space at
treatment, storage, or disposal facilities. Regardless of the location, the conversion of land to
meet waste disposal needs would reduce the long-term productivity of the land.
Power plant facilities would be committed to electricity production over the short term. After
decommissioning these facilities and restoring the power plant site, the land would become
available for other productive uses.
The nature of the relationship between short-term use of the environment and long-term
productivity would vary among nuclear power plants and would depend on the specific
characteristics of each plant and its interaction with the environment. This relationship is
evaluated in plant-specific SEISs.

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4.15.3

Irreversible and Irretrievable Commitment of Resources

An irreversible or irretrievable commitment of resources refers to impacts on or losses of
resources that cannot be recovered or reversed. Irreversible and irretrievable commitment of
resources for electrical power generation are considered to include the commitment of land,
water, energy, raw materials, and other natural and human-made resources required for power
plant operations during the license renewal term and any refurbishment activities that might be
carried out that would not otherwise have taken place if the operating licenses had not been
renewed. This section describes the irreversible and irretrievable commitments of resources that
have been identified in this LR GEIS. A commitment of resources is irreversible when primary or
secondary impacts limit the future options for a resource. It primarily applies to the impacts of
use of nonrenewable resources, such as minerals or cultural resources, or to factors, such as
soil productivity, that are renewable only over long periods of time. An irretrievable commitment
refers to the use or consumption of resources neither renewable nor recoverable for future use.
Irretrievable commitment applies to the loss of production, harvest, or natural resources. For
example, if farmland is used for a nonagricultural purpose such as energy generation, some or
all of the agricultural production from the farmland is lost irretrievably while the area is
temporarily used for another purpose. The production lost is irretrievable, but the action is not
irreversible. In general, the commitment of capital, energy, labor, and material resources would
also be irreversible.
Resources include materials and equipment required for nuclear power plant maintenance and
operation, energy and water needed to run the plants, the nuclear fuel used by the reactors to
generate electricity, and the land required to permanently dispose of the radioactive and
nonradioactive wastes. Some of these resources could be retrieved and reused at the end of
the license renewal (initial LR or SLR) term. For example, some reactor equipment can be used
at other reactors or can be decontaminated and released for recycling or restricted or
unrestricted use by others. However, some of the equipment and irradiated components that
might be replaced during the license renewal term might not be reused or recycled and
therefore would need to be permanently disposed of. In addition, the fossil fuels used by power
plants would be permanently lost. Most of the water used by power plants relying on
once-through cooling is returned to the surface waterbodies that supply the cooling water. The
relatively small portion of the water that evaporates to the air would be lost to the local
waterbodies and the region but would be returned to the environment as part of the hydrologic
cycle, potentially within another watershed. For closed-cycle cooling systems, a much larger
percentage of the water used for cooling would be lost to evaporation, but that, too, would be
returned as part of the hydrologic cycle.
The most significant irreversible and irretrievable commitment of resources related to nuclear
power plant operations during the license renewal term would be the nuclear fuel used to
generate electricity and the land used to dispose of and store wastes, including spent nuclear
fuel, generated during the license renewal term. The treatment, storage, and disposal of LLW,
hazardous waste, and nonhazardous waste would require the irretrievable commitment of
energy and fuel and could result in the irreversible commitment of space in disposal facilities.
Some of the land used for the disposal of LLW may be available for other uses in a few hundred
years because of the nearly complete decay of short-lived radionuclides in LLW, but most of the
land used for the disposal of some mixed or hazardous wastes could be permanently
(irreversibly) lost.

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The irreversible and irretrievable commitment of resources would not be the same for all nuclear
power plants and would depend on the specific characteristics of the power plant and its
resource needs. This commitment is evaluated in plant-specific SEISs.
The implementation of any of the replacement energy alternatives would entail the irreversible
and irretrievable commitment of energy, water, chemicals, and, in some cases, fossil fuels.
These resources would be committed over the entire life cycle of the power plant—construction,
operation, and decommissioning—and would essentially be unrecoverable.
Energy expended would be in the form of fuel for equipment, vehicles, power plant operations,
and electricity for power plant construction and facility operations. Electricity and fuels would be
purchased from offsite commercial sources. Water would be obtained from existing water supply
systems. These resources are generally available, and the amounts required would not be
expected to deplete available supplies or exceed available system capacities.
The irreversible and irretrievable commitment of material resources are the materials that
cannot be recovered or recycled, materials that are rendered radioactive and/or cannot be
decontaminated, and materials consumed or reduced to unrecoverable forms of waste.
However, none of the resources used by potential replacement energy-generating facilities is in
short supply, and, for the most part, they are readily available.
Various materials and chemicals, including acids and caustics, would be required to support
operations activities. These materials would be derived from commercial vendors, and their
consumption would not be expected to affect local, regional, or national supplies.

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REFERENCES1

7 CFR Part 657. Code of Federal Regulations, Title 7, Agriculture, Part 657, “Prime and Unique
Farmlands.”
7 CFR Part 658. Code of Federal Regulations, Title 7, Agriculture, Part 658, “Farmland
Protection Policy Act.”
10 CFR Part 2. Code of Federal Regulations, Title 10, Energy, Part 2, “Agency Rules of Practice
and Procedure.”
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Protection Regulations for Domestic Licensing and Related Regulatory Functions.”
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Requirements for Land Disposal of Radioactive Waste.”
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10 CFR Part 72. Code of Federal Regulations, Title 10, Energy, Part 72, “Licensing
Requirements for the Independent Storage of Spent Nuclear Fuel, High-Level Radioactive
Waste, and Reactor-Related Greater than Class C Waste.”
10 CFR Part 100. Code of Federal Regulations, Title 10, Energy, Part 100, “Reactor Site
Criteria.”

1

Many references cited in this document and listed in this chapter are available through the NRC Library
on the NRC’s public web site at http://www.nrc.gov/reading-rm/doc-collections/ and through the NRC’s
Agencywide Documents Access and Management System (ADAMS) at http://www.nrc.gov/readingrm/adams.html. Other references include open literature items, such as books, journal articles,
transactions, Federal Register notices, Federal and State legislation, and congressional reports. Such
documents may be accessed at the website listed in the reference or may be purchased from the
sponsoring organization, as appropriate.

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References
15 CFR Part 922. Code of Federal Regulations, Title 15, Commerce and Foreign Trade,
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Part 60, “National Register of Historic Places.”
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Part 61, “Procedures for State, Tribal, and Local Government Historic Preservation Programs.”
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Part 800, “Protection of Historic Properties.”
40 CFR Part 50. Code of Federal Regulations, Title 40, Protection of Environment, Part 50,
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“Requirements for Preparation, Adoption, and Submittal of Implementation Plans.”
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“National Emission Standards for Hazardous Air Pollutants.”
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“Determining Conformity of Federal Actions to State or Federal Implementation Plans.”
40 CFR Part 120. Code of Federal Regulations, Title 40, Protection of Environment, Part 120,
“Definition of Waters of the United States.”
40 CFR Part 121. Code of Federal Regulations, Title 40, Protection of Environment, Part 121,
“State Certification of Activities Requiring a Federal License or Permit.”
40 CFR Part 122. Code of Federal Regulations, Title 40, Protection of Environment, Part 122,
“EPA Administered Permit Programs: The National Pollutant Discharge Elimination System.”
40 CFR Part 125. Code of Federal Regulations, Title 40, Protection of Environment, Part 125,
“Criteria and Standards for the National Pollutant Discharge Elimination System.”
40 CFR Part 125 Subpart H. Code of Federal Regulations, Title 40, Protection of Environment,
Part 125, “Criteria and Standards for the National Pollutant Discharge Elimination System,”
Subpart H, Criteria for Determining Alternative Effluent Limitations Under Section 316(a) of the
Act.
40 CFR Part 141. Code of Federal Regulations, Title 40, Protection of Environment, Part 141,
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40 CFR Part 143. Code of Federal Regulations, Title 40, Protection of Environment, Part 143,
“National Secondary Drinking Water Regulations.”
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References
40 CFR Part 190. Code of Federal Regulations, Title 40, Protection of Environment, Part 190,
“Environmental Radiation Protection Standards for Nuclear Power Operations.”
40 CFR Part 192. Code of Federal Regulations, Title 40, Protection of Environment, Part 192,
“Health and Environmental Protection Standards for Uranium and Thorium Mill Tailings.”
40 CFR Part 261. Code of Federal Regulations, Title 40, Protection of Environment, Part 261,
“Identification and Listing of Hazardous Waste.”
40 CFR Part 273. Code of Federal Regulations, Title 40, Protection of Environment, Part 273,
“Standards for Universal Waste Management.”
40 CFR Part 1501. Code of Federal Regulations, Title 40, Protection of Environment, Part 1501,
“NEPA and Agency Planning.”
40 CFR Part 1502. Code of Federal Regulations, Title 40, Protection of Environment, Part 1502,
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40 CFR Part 1508. Code of Federal Regulations, Title 40, Protection of Environment, Part 1508,
“Definitions.”
44 CFR Part 353 Appendix A. Code of Federal Regulations, Title 44, Emergency Management
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R.W. Borchardt, dated April 2, 2009, regarding “Staff Requirements – SECY-08-0197 – Options
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B.S. Mallett and C.A. Casto, dated March 5, 2010, regarding “Groundwater Contamination Task
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ADAMS Accession No. ML11133A029.
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for License Renewal of Nuclear Plants, Supplement 45: Regarding Hope Creek Generating
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M.A. Satorius, dated December 20, 2013, regarding “Staff Requirements - SECY-13-0108 Staff Recommendations for Addressing Remediation of Residual Radioactivity During
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NRC FORM 335

U.S. NUCLEAR REGULATORY COMMISSION

(12-2010)
NRCMD 3.7

1. REPORT NUMBER
(Assigned by NRC, Add Vol., Supp., Rev., and
Addendum Numbers, if any.)

BIBLIOGRAPHIC DATA SHEET
(See instructions on the reverse)

2. TITLE AND SUBTITLE

Generic Environmental Impact Statement for License Renewal of Nuclear Plants
Main Report

NUREG-1437, Volume 1,
Revision 2
Final Report
3. DATE REPORT PUBLISHED
MONTH

YEAR

August

2024

Final Report

4. FIN OR GRANT NUMBER

5. AUTHOR(S)

6. TYPE OF REPORT

See Appendix H of this Report.

Technical
7. PERIOD COVERED (Inclusive Dates)

8. PERFORMING ORGANIZATION - NAME AND ADDRESS (If NRC, provide Division, Office or Region, U. S. Nuclear Regulatory Commission, and mailing address; if
contractor, provide name and mailing address.)

Office of Nuclear Material Safety and Safeguards
U.S. Nuclear Regulatory Commission
Washington, DC 20555-0001
9. SPONSORING ORGANIZATION - NAME AND ADDRESS (If NRC, type "Same as above", if contractor, provide NRC Division, Office or Region, U. S. Nuclear
Regulatory Commission, and mailing address.)

Same as 8 above.
10. SUPPLEMENTARY NOTES

11. ABSTRACT (200 words or less)

U.S. Nuclear Regulatory Commission (NRC) regulations allow for the renewal of commercial nuclear power plant
operating licenses. There are no specific limitations in the Atomic Energy Act or the NRC’s regulations restricting the
number of times a license may be renewed. To support license renewal environmental reviews, the NRC published the
first Generic Environmental Impact Statement for License Renewal of Nuclear Plants (LR GEIS) in 1996. Per NRC
regulations, a review and update of the LR GEIS is conducted every 10 years, if necessary. The proposed action is the
renewal of nuclear power plant operating licenses.
Since publication of the 1996 LR GEIS, 59 nuclear power plants (96 reactor units) have undergone license renewal
environmental reviews and have received renewed licenses (either an initial license renewal [initial LR] or subsequent
license renewal [SLR]), the results of which were published as supplements to the LR GEIS. This revision evaluates the
issues and findings of the 2013 LR GEIS (Revision 1). Lessons learned and knowledge gained from initial LR and SLR
environmental reviews provide major sources of new information for this assessment. In addition, new research,
findings, public comments, changes in applicable laws and regulations, and other information were considered in
evaluating the environmental impacts associated with license renewal. Additionally, this revision fully considers and
evaluates the environmental impacts of initial LR and one term of SLR.
12. KEY WORDS/DESCRIPTORS (List words or phrases that will assist researchers in locating the report.)

Generic Environmental Impact Statement for License Renewal of Nuclear Plants
LR GEIS
NUREG-1437, Revision 2
National Environmental Policy Act
NEPA
License Renewal
Initial LR
Subsequent License Renewal
SLR

13. AVAILABILITY STATEMENT

unlimited
14. SECURITY CLASSIFICATION
(This Page)

unclassified
(This Report)

unclassified
15. NUMBER OF PAGES

16. PRICE

NRC FORM 335 (12-2010)

NUREG-1437, Volume 1
Revision 2

Generic Environmental Impact Statement for License Renewal of
Nuclear Plants

August 2024