Draft Regulatory Guide

U.S. NUCLEAR REGULATORY COMMISSION
OFFICE OF NUCLEAR REGULATORY RESEARCH

March 2016
Division 1

DRAFT REGULATORY GUIDE
Technical Contact
Anthony Cinson
(301) 415-2393

DRAFT REGULATORY GUIDE DG-1297
(Proposed Revision 2 to Regulatory Guide 1.192, dated March 2016)

OPERATION AND MAINTENANCE CODE CASE ACCEPTABILITY,
ASME OM CODE
Purpose
This regulatory guide (RG) lists Code Cases associated with the American Society of Mechanical
Engineers (ASME) Code for Operation and Maintenance of Nuclear Power Plants (OM Code) (Ref. 1)
that the U.S. Nuclear Regulatory Commission (NRC) has approved for use as voluntary alternatives to the
mandatory ASME OM Code provisions that are incorporated by reference into Title 10, Part 50, of the
Code of Federal Regulations (10 CFR Part 50), “Domestic Licensing of Production and Utilization
Facilities” (Ref. 2). The editions and addenda of the ASME Code for Operation and Maintenance of
Nuclear Power Plants have had different titles from 2005 to 2012 and are referred to collectively in this
RG as the OM Code.
Applicable Rules and Regulations
•

General Design Criterion (GDC) 1, “Quality Standards and Records,” of Appendix A, “General
Design Criteria for Nuclear Power Plants,” to 10 CFR Part 50 requires, in part, that structures,
systems, and components important to safety be designed, fabricated, erected, and tested to
quality standards commensurate with the importance of the safety function to be performed.
Where generally recognized codes and standards are used, Criterion 1 requires that they be
identified and evaluated to determine their applicability, adequacy, and sufficiency and be
supplemented or modified as necessary to ensure a quality product in keeping with the required
safety function.

•

Criterion 30, “Quality of Reactor Coolant Pressure Boundary,” of Appendix A to 10 CFR Part 50
requires, in part, that components that are part of the reactor coolant pressure boundary be
designed, fabricated, erected, and tested to the highest practical quality standards.

This regulatory guide is being issued in draft form to involve the public in the early stages of the development of a regulatory
position in this area. It has not received final staff review or approval and does not represent an official NRC final staff position.
Public comments are being solicited on this draft guide (including any implementation schedule) and its associated regulatory
analysis or value/impact statement. Comments should be accompanied by appropriate supporting data. Written comments may be
submitted to the Rules, Announcements, and Directives Branch, Office of Administration, U.S. Nuclear Regulatory Commission,
Washington, DC 20555-0001; submitted through the NRC’s interactive rulemaking Web page at http://www.nrc.gov; or faxed to
(301) 492-3446. Copies of comments received may be examined at the NRC’s Public Document Room, 11555 Rockville Pike,
Rockville, MD. Comments will be most helpful if received by 5/16/2016.
Electronic copies of this draft regulatory guide are available through the NRC’s interactive rulemaking Web page (see above); the
NRC’s public Web site under Draft Regulatory Guides in the Regulatory Guides document collection of the NRC Library 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, under Accession No. ML15027A330.

•

Appendix B, “Quality Assurance Criteria for Nuclear Power Plants and Fuel Processing
Plants,” to 10 CFR Part 50 requires, in part, a program for inspection of activities
affecting quality to verify conformance with documented instructions and procedures.

•

10 CFR 50.55a(f), “Inservice Testing Requirements,” requires, in part, that Class 1, 2, and 3
components and their supports meet the requirements of the ASME OM Code or equivalent
quality standards.

Related Guidance
•

Regulatory Guide 1.84, “Design, Fabrication, and Materials Code Case Acceptability, ASME
Section III,” (Ref. 3) lists the ASME Boiler and Pressure Vessel Code (BPV Code), Section III
Code Cases that the NRC has approved for use as voluntary alternatives to the mandatory ASME
BPV Code provisions that are incorporated into 10 CFR 50.55a.

•

Regulatory Guide 1.147, “Inservice Inspection Code Case Acceptability, ASME Section XI,
Division 1,” (Ref. 4) lists the ASME BPV Code, Section XI Code Cases that the NRC has
approved for use as voluntary alternatives to the mandatory ASME BPV Code provisions that are
incorporated into 10 CFR 50.55a.

•

Regulatory Guide 1.193, “ASME Code Cases Not Approved for Use,” (Ref. 5) lists the ASME
BPV Code, Section III and Section XI Code Cases, and ASME OM Code Cases, that the NRC
has not approved for generic use.

Purpose of This Regulatory Guide
The NRC will amend 10 CFR 50.55a to incorporate by reference the new Code Cases and revisions to
existing Code Cases listed as approved in Tables 1 and 2 of this guide, and to state the requirements
governing the use of Code Cases. Code Cases approved by the NRC may be used voluntarily by
applicants or licensees as an alternative to compliance with ASME Code provisions that have been
incorporated by reference into 10 CFR 50.55a. Because of continuing change in the status of Code Cases,
the staff plans periodic updates to 10 CFR 50.55a and this guide to accommodate new Code Cases and
any revisions of existing Code Cases.
Paperwork Reduction Act (Ref. 6)
This regulatory guide contains information collection requirements covered by 10 CFR Part 50 that
the Office of Management and Budget (OMB) approved under OMB control number 3150-0011. The
NRC may neither conduct nor 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 OMB control number.

DG-1297, Page 2

B. DISCUSSION
Reason of Revision
Revision 2 of RG 1.192 includes new information reviewed by the NRC with respect to OM
Code Cases listed in the 2009 Edition through the 2012 Edition of the ASME OM Code. This is an update
to RG 1.192, Revision 1, which included information from the 2002 Addenda through the 2006 Addenda
of the OM Code.
Background
Provisions of the ASME BPV Code have been used since 1971 as one part of the framework to
establish the necessary design, fabrication, construction, testing, and performance requirements for
structures, systems, and components important to safety in nuclear power plants. Among other things,
ASME standards committees develop improved methods for the construction, inservice inspection (ISI),
and inservice testing (IST) of ASME Class 1, 2, 3, MC (metal containment), and CC (concrete
containment) nuclear power plant components. A broad spectrum of stakeholders participates in the
ASME process, which helps to ensure that the various interests are considered.
In 1990, the ASME published the initial edition of the OM Code that provides rules for IST and
inservice examination of pumps, valves, and dynamic restraints (snubbers). The OM Code was developed
and is maintained by the ASME Committee on Operation and Maintenance of Nuclear Power Plants. The
OM Code was developed in response to the ASME Board on Nuclear Codes and Standards directive that
transferred responsibility for development and maintenance of rules for the IST and inservice examination
of pumps, valves, and dynamic restraints (snubbers) from the ASME Section XI Subcommittee on
Nuclear Inservice Inspection to the ASME OM Committee. The ASME intended the OM Code to replace
Section XI rules for IST and inservice examination of pumps, valves, and dynamic restraints (snubbers),
and the Section XI rules for IST and inservice examination of these components that had been
incorporated by reference into NRC regulations have been deleted from Section XI. The NRC endorsed
the OM Code for the first time in an amendment to 10 CFR 50.55a published on September 22, 1999 (64
FR 51370). The NRC endorsed OM Code Cases through this guide for the first time in June 2003. It
should be noted that the title of the OM Code was changed beginning with the 2009 Edition to “Operation
and Maintenance of Nuclear Power Plants.”
The ASME periodically publishes a new edition of the OM Code. The latest editions and addenda
of the OM Code that have been approved for use by the NRC are referenced in 10 CFR 50.55a(a)(1)(iv).
The ASME also periodically publishes OM Code Cases. Code Cases provide alternatives to existing OM
Code requirements that the ASME developed and approved. This regulatory guide identifies the OM
Code Cases that have been determined by the NRC to be acceptable alternatives to applicable parts of the
OM Code. Applicants or licensees may use these Code Cases without requesting authorization from the
NRC, provided that they are used with any identified limitations or modifications. OM Code Cases not
yet endorsed by the NRC may be used by a licensee or applicant through 10 CFR 50.55a(z). That section
permits the use of alternatives to the Code requirements referenced in 10 CFR 50.55a provided that the
proposed alternatives result in an acceptable level of quality and safety and that their use is authorized by
the Director of the Office of Nuclear Reactor Regulation or Office or the Office of New Reactors, as
applicable.
The ASME OM Code is incorporated by reference into 10 CFR 50.55a, which the NRC will amend
to incorporate this guide by reference; 10 CFR 50.55a states the requirements governing the use of Code
Cases. Because of continuing change in the status of Code Cases, the staff plans periodic updates to
10 CFR 50.55a and this guide to accommodate new Code Cases and any revisions of existing Code
DG-1297, Page 3

Cases. Code Cases approved by the NRC provide an acceptable voluntary alternative to the mandatory
ASME OM Code provisions.
When an applicant or licensee initially implements a Code Case, 10 CFR 50.55a requires that
the most recent version of that Code Case as listed in Tables 1 and 2 be implemented. If a Code Case is
implemented by an applicant or licensee and a later version of the Code Case is incorporated by reference
into 10 CFR 50.55a and listed in Tables 1 and 2 during the licensee’s present 120-month IST program
interval, that licensee may use either the later version or the previous version. An exception to this
provision would be the inclusion of a condition on the use of the Code Case that is necessary, for
example, to enhance safety. Licensees who choose to continue use of the Code Case during
the subsequent 120-month IST program interval will be required to implement the latest version
incorporated by reference into 10 CFR 50.55a and listed in Tables 1 and 2.
Code Cases may be annulled because the provisions have been incorporated into the Code, the
application for which it was specifically developed no longer exists, or experience has shown that an
examination or testing method is no longer adequate. After a Code Case is annulled and 10 CFR 50.55a
and this guide are amended, applicants or licensees may not implement that Code Case for the first time.
However, an applicant or licensee who implemented the Code Case prior to annulment may continue to
use that Code Case through the end of the present IST interval. An annulled Code Case cannot be used in
the subsequent IST interval unless implemented as an approved alternative under 10 CFR 50.55a(z).
If a Code Case is incorporated by reference into 10 CFR 50.55a and later annulled by the ASME because
experience has shown that an examination or testing method is inadequate, the NRC will amend 10 CFR
50.55a and this guide to remove the approval of the annulled Code Case. Applicants or licensees should
not begin to implement such annulled Code Cases prior to the rulemaking. Notwithstanding these
requirements, the Commission may impose new or revised Code requirements, including implementation
schedules, which it determines are consistent with the Backfit Rule (10 CFR 50.109).
A Code Case may be revised, for example, to incorporate user experience. The older or
superseded version of the Code Case cannot be applied by the licensee or applicant for the first time. If an
applicant or a licensee applied a Code Case before it was listed as superseded, the applicant or the
licensee may continue to use the Code Case until the applicant or the licensee updates its construction
Code of Record (in the case of an applicant, updates its application) or until the licensee’s 120-month IST
update interval expires, after which the continued use of the Code Case is prohibited unless NRC
approval is granted under 10 CFR Part 50.55a(z). If a Code Case is incorporated by reference into 10 CFR
Part 50.55a and later a revised version is issued by the ASME because experience has shown that the
design analysis, construction method, examination method, or testing method is inadequate; the NRC will
amend 10 CFR Part 50.55a and the relevant RG to remove the approval of the superseded Code Case.
Applicants and licensees should not begin to implement such superseded Code Cases in advance of the
rulemaking.
OM Code Cases determined by the NRC to be unacceptable are listed in Regulatory Guide 1.193,
“ASME Code Cases Not Approved for Use.”
With regard to the use of any Code Case, it is the responsibility of the user to make certain that the
provisions of the Code Case do not conflict with regulatory requirements or licensee commitments.

C. STAFF REGULATORY GUIDANCE
For Revision 2 of Regulatory Guide 1.192, the NRC reviewed the OM Code Cases listed in the
2009 Edition through the 2012 Edition of the ASME OM Code. Appendix A to this guide is a complete
list of all OM Code Cases published by the ASME. The table in Appendix A lists the action taken by the

DG-1297, Page 4

ASME (e.g., new or revised Code Case), the edition or addenda in which the Code Case was published,
and the table in the regulatory guide where each Code Case may be found. Regulatory Guide 1.192,
Revision 2, Draft Regulatory Guide (DG) 1297, would supersede the incorporation by reference of
Revision 1. The Code Cases addressed by this regulatory guide are listed in three tables:
(1)

Table 1, “Acceptable OM Code Cases,” lists the Code Cases that are acceptable to the NRC for
implementation in the IST of light-water-cooled nuclear power plants.

(2)

Table 2, “Conditionally Acceptable OM Code Cases,” lists the Code Cases that are acceptable,
provided that they are used with the identified conditions (i.e., the Code Case is generally
acceptable but the NRC has determined that the requirements in the Code Case, which are
alternatives to the OM Code, must be supplemented in order to provide an acceptable level of
quality and safety).

(3)

Table 3, “OM Code Cases That Have Been Superseded by Revised Code Cases,” lists Code Cases
that have been superseded through revision.

1.

Acceptable Code Cases

The Code Cases listed in the table below are acceptable to the NRC for application in an applicant’s
or licensee’s IST programs. The OM Code uses two approaches to list revisions of Code Cases. The first
approach lists Code Cases according to edition or addenda (e.g., OMN-6, 2012 Edition). The second
approach uses a numbering system (e.g., OMN-1, Revision 1). Thus, the tables below show either the
latest edition or addenda in which a Code Case was published, or the latest revision number of a Code
Case, in accordance with the requirement in 10 CFR 50.55a that licensees or applicants implement the
most recent version of a Code Case. The edition and addenda is being listed in addition to the revision
number because the OM Code in some cases reaffirms Code Cases with minor changes. Listing both the
revision number and edition or addenda will ensure that the latest version of the Code Case is
implemented. To assist users, new and revised Code Cases are shaded to distinguish them from those
approved in previous versions of this guide. The shading will assist in focusing attention during the public
comment period on the changes to the guide.
Table 1. Acceptable OM Code Cases
Code Case
Number

Table 1
Acceptable OM Code Cases

OMN-2
(2012 Edition)

Thermal Relief Valve Code Case, OM Code-1995, Appendix I
(OMN-2, 2004 Edition, was unconditionally approved in Rev. 1 of RG 1.192)

OMN-5
(2012 Edition)

Testing of Liquid Service Relief Valves Without Insulation
(OMN-5, 2006 Addenda, was unconditionally approved in Rev. 1 of RG 1.192)

OMN-6
(2012 Edition)

Alternate Rules for Digital Instruments
(OMN-6, 2006 Addenda, was unconditionally approved in Rev. 1 of RG 1.192)

DG-1297, Page 5

Code Case
Number

Table 1
Acceptable OM Code Cases

OMN-7
(2012 Edition)

Alternative Requirements for Pump Testing
(OMN-7, 2000 Addenda, was unconditionally approved in Rev. 1 of RG 1.192)

OMN-8
(2012 Edition)

Alternative Rules for Preservice and Inservice Testing of Power-Operated Valves That Are Used
for System Control and Have a Safety Function per OM-10, ISTC-1.1, or ISTA-1100
(OMN-8, 2006 Addenda, was unconditionally approved in Rev. 1 of RG 1.192)

OMN-13,
Revision 2
(2012 Edition)

Performance-Based Requirements for Extending Snubber Inservice Visual Examination Interval
at LWR Power Plants
(OMN-13, 2004 Edition, was unconditionally approved in Rev. 1 of RG 1.192)

OMN-14
(2012 Edition)

Alternative Rules for Valve Testing Operations and Maintenance, Appendix I: BWR CRD
Rupture Disk Exclusion
(OMN-14, 2004 Edition, was unconditionally approved in Rev. 1 of RG 1.192)

OMN-15,
Revision 2
(2012 Edition)

Performance-Based Requirements for Extending the Snubber Operational Readiness Testing
Interval at LWR Power Plants
(OMN-15, 2004 Edition, and 2006 Addenda, were not approved for use and were listed in RG
1.193)

OMN-17
(2012 Edition)

Alternative Rules for Testing ASME Class 1 Pressure Relief/Safety Valves

OMN-20
(2012 Edition)

Inservice Test Frequency

DG-1297, Page 6

2.

Conditionally Acceptable Code Cases

The Code Cases listed in Table 2 are acceptable to the NRC for application in an applicant’s or
licensee’s IST programs within the conditions indicated by the NRC. The OM Code uses two approaches
to list revisions of Code Cases. The first approach lists Code Cases according to edition or addenda (e.g.,
OMN-6, 2012 Edition). The second approach uses a numbering system (e.g., OMN-1, Revision 1). Thus,
the tables below show either the latest edition or addenda in which a Code Case was published, or the
latest revision number of a Code Case, in accordance with the requirement in 10 CFR 50.55a that
licensees or applicants implement the most recent version of a Code Case. The edition and addenda are
being listed in addition to the revision number because the OM Code in some cases reaffirms Code Cases
with minor changes. Listing both the revision number and edition or addenda will ensure that the latest
version of the Code Case is implemented. To assist users, new and revised Code Cases are shaded to
distinguish them from those approved in previous versions of this guide. The shading will assist in
focusing attention during the public comment period on the changes to the guide.
Table 2. Conditionally Acceptable OM Code Cases
Code Case
Number

Table 2
Conditionally Acceptable OM Code Cases
Title/Condition

OMN-1
(Revision 1)
2012 Edition

Alternative Rules for Preservice and Inservice Testing of Active Electric Motor-Operated Valve
Assemblies in Light-Water Reactor Power Plants
Applicants and licensees may use this Code Case in lieu of the provisions for stroke-time testing in
Subsection ISTC of the 1995 Edition up to and including the 2012 Edition of the ASME OM Code
when applied in conjunction with the provisions for leakage rate testing in, as applicable, ISTC 4.3
(1995 Edition with the 1996 and 1997 Addenda) and ISTC-3600 (1998 Edition through the 2012
Edition). In addition, applicants and licensees who continue to implement Section XI of the ASME
BPV Code as their Code of Record may use OMN-1 in lieu of the provisions for stroke-time testing
specified in Paragraph 4.2.1 of ASME/ANSI OM Part 10 as required by 10 CFR 50.55a(b)(2)(vii)
subject to the conditions in this regulatory guide. Applicants and licensees who choose to apply
OMN-1 must apply all its provisions.
(1) The adequacy of the diagnostic test interval for each motor-operated valve (MOV) must be
evaluated and adjusted as necessary, but not later than 5 years or three refueling outages
(whichever is longer) from initial implementation of OMN-1.
(2) When extending exercise test intervals for high risk MOVs beyond a quarterly frequency,
applicants or licensees must ensure that the potential increase in Core Damage Frequency
(CDF) and risk associated with the extension is small and consistent with the intent of the
Commission’s Safety Goal Policy Statement.
(3) When applying risk insights as part of the implementation of OMN-1, applicants or licensees
must categorize MOVs according to their safety significance using the methodology described
in Code Case OMN-3, “Requirements for Safety Significance Categorization of Components
Using Risk Insights for Inservice Testing of LWR Power Plants,” with the conditions
discussed in this regulatory guide or use other MOV risk ranking methodologies accepted by
the NRC on a plant specific or industry-wide basis with the conditions in the applicable safety
evaluations.
Note 1: As indicated at 64 FR 51370-51386, applicants and licensees are cautioned that, when
implementing OMN-1, the benefits of performing a particular test should be balanced against the
potential adverse effects placed on the valves or systems caused by this testing.
Note 2: These conditions are identical to those imposed on OMN-1 (2006 Addenda) in Revision 1
to Regulatory Guide 1.192.

DG-1297, Page 7

Code Case
Number

Table 2
Conditionally Acceptable OM Code Cases
Title/Condition

OMN-3
(2012 Edition)

Requirements for Safety Significance Categorization of Components Using Risk Insights for
Inservice Testing of LWR Power Plants
(1) In addition to those components identified in the ASME IST Program Plan, implementation of
Section 1, “Applicability,” of the Code Case must include within the scope of an applicant’s or
licensee’s risk-informed IST program non-ASME Code components categorized as high safety
significant components (HSSCs) that might not currently be included in the IST Program Plan.
(2) The decision criteria discussed in Section 4.4.1, “Decision Criteria,” of the Code Case for
evaluating the acceptability of aggregate risk effects (i.e., for Core Damage Frequency [CDF]
and Large Early Release Frequency [LERF]) must be consistent with the guidance provided in
Regulatory Guide 1.174, “An Approach for Using Probabilistic Risk Assessment in RiskInformed Decisions on Plant-Specific Changes to the Licensing Basis” (Ref. 7).
(3) Section 4.4.4, “Defense in Depth,” of the Code Case must be consistent with the guidance
contained in Sections 2.2.1, “Defense-in-Depth Evaluation,” and 2.2.2, “Safety Margin
Evaluation,” of Regulatory Guide 1.175, “An Approach for Plant-Specific, Risk-Informed
Decisionmaking: Inservice Testing” (Ref. 8).
(4) Implementation of Sections 4.5, “Inservice Testing Program,” and 4.6, “Performance
Monitoring,” of the Code Case must be consistent with the guidance pertaining to inservice
testing of pumps and valves provided in Section 3.2, “Program Implementation,” and Section
3.3, “Performance Monitoring,” of Regulatory Guide 1.175. Testing and performance
monitoring of individual components must be performed as specified in the risk-informed
components Code Cases (e.g., OMN-1, OMN-4, OMN-7, and OMN-12, as modified by the
conditions discussed in this regulatory guide).
(5) Implementation of Section 3.2, “Plant Specific PRA,” of the Code Case must be consistent with
the guidance that the Owner is responsible for demonstrating and justifying the technical
adequacy of the probabilistic risk assessment (PRA) analyses used as the basis to perform
component risk ranking and for estimating the aggregate risk impact. Regulatory Guide 1.200,
“An Approach for Determining the Technical Adequacy of Probabilistic Risk Assessment
Results for Risk-Informed Activities” (Ref. 9), provides guidance for determining the technical
adequacy of the PRA used in a risk-informed regulatory activity. Regulatory Guide 1.201,
“Guidelines for Categorizing Structures, Systems, and Components in Nuclear Power Plants
According to their Safety Significance” (Ref. 10), describes one acceptable method to
categorize the safety significance of an active component, including methods to use when a
plant-specific PRA that meets the appropriate Regulatory Guide 1.200 capability for specific
hazard group(s) (e.g., seismic and fire) is not available.
(6) Section 4.2.4, “Reconciliation,” paragraph (b), is not endorsed. The expert panel may not
classify components that are ranked HSSC by the results of a qualitative or quantitative PRA
evaluation (excluding the sensitivity studies) or the defense-in-depth assessment to low safety
significant component (LSSC).

DG-1297, Page 8

Code Case
Number

Table 2
Conditionally Acceptable OM Code Cases
Title/Condition

OMN-3
(2012 Edition)
(cont’d)

Requirements for Safety Significance Categorization of Components Using Risk Insights for
Inservice Testing of LWR Power Plants
(7) Implementation of Section 3.3, “Living PRA,” must be consistent with the following: (1) To
account for potential changes in failure rates and other changes that could affect the PRA,
changes to the plant must be reviewed, and, as appropriate, the PRA updated; (2) When the
PRA is updated, the categorization of structures, systems, and components must be reviewed
and changed if necessary to remain consistent with the categorization process; and (3) The
review of plant changes must be performed in a timely manner and must be performed once
every two refueling outages or as required by 10 CFR 50.71(h)(2) for combined license holders.
Note 1: The Code Case methodology for risk ranking uses two categories of safety significance.
The NRC staff has determined that this is acceptable for ranking all component types. However, the
NRC staff has accepted other methodologies for risk ranking MOVs, with certain conditions, that
use three categories of safety significance.
Note 2: These conditions are identical to those imposed on OMN-3 (2004 Edition) in Revision 1 to
Regulatory Guide 1.192.

OMN-4
(2012 Edition)

OMN-9
(2012 Edition)

Requirements for Risk Insights for Inservice Testing of Check Valves at LWR Power Plants
(1) Valve opening and closing functions must be demonstrated when flow testing or examination
methods (nonintrusive, or disassembly and inspection) are used.
(2) The initial interval for tests and associated examinations may not exceed two fuel cycles or 3
years, whichever is longer; any extension of this interval may not exceed one fuel cycle per
extension with the maximum interval not to exceed 10 years. Trending and evaluation of
existing data must be used to reduce or extend the time interval between tests.
(3) If the Appendix II condition monitoring program is discontinued, the requirements of ISTC
4.5.1, “Exercising Test Frequency,” through ISTC 4.5.4, “Valve Obturator Movement,” (1996
and 1997 Addenda) or ISTC 3510, 3520, 3540, and 5221 (1998 Edition through 2012 Edition),
as applicable, must be implemented.
Note 1: The conditions are identical to those imposed on OMN-4 (2004 Edition) in Revision 1 to
Regulatory Guide 1.192.
Note 2: The conditions with respect to allowable methodologies for OMN-3 risk ranking specified
for the use of OMN-1 also apply to OMN-4.
Use of a Pump Curve for Testing
(1) When a reference curve may have been affected by repair, replacement, or routine servicing of a
pump, a new reference curve must be determined, or an existing reference curve must be
reconfirmed, in accordance with Section 3 of this Code Case.
(2) If it is necessary or desirable, for some reason other than that stated in Section 4 of this Code
Case, to establish an additional reference curve or set of curves, these new curves must be
determined in accordance with Section 3.
Note 1: The conditions are identical to those imposed on OMN-9 (2004 Edition) in Revision 1 to
Regulatory Guide 1.192.

DG-1297, Page 9

Code Case
Number

Table 2
Conditionally Acceptable OM Code Cases
Title/Condition

OMN-12
(2012 Edition)

Alternative Requirements for Inservice Testing Using Risk Insights for Pneumatically and
Hydraulically Operated Valve Assemblies in Light-Water Reactor Power Plants (OM-Code 1998,
Subsection ISTC)
(1) Paragraph 4.2, “Inservice Test Requirements,” of OMN-12 specifies inservice test requirements
for pneumatically and hydraulically operated valve assemblies categorized as high safety
significant within the scope of the Code Case. The inservice testing program must include a
mix of static and dynamic valve assembly performance testing. The mix of valve assembly
performance testing may be altered when justified by an engineering evaluation of test data.
(2) Paragraph 4.2.2.3 of OMN-12 specifies the periodic test requirements for pneumatically and
hydraulically operated valve assemblies categorized as high safety significant within the scope
of the code case. The adequacy of the diagnostic test interval for each high safety significant
valve assembly must be evaluated and adjusted as necessary, but not later than 5 years or three
refueling outages (whichever is longer) from initial implementation of OMN-12.
(3) Paragraph 4.2.3, “Periodic Valve Assembly Exercising,” of OMN-12 specifies periodic
exercising for pneumatically and hydraulically operated valve assemblies categorized as high
safety significant within the scope of the code case. Consistent with the requirement in OMN-3
to evaluate the aggregate change in risk associated with changes in test strategies, when
extending exercise test intervals for high safety significant valve assemblies beyond a quarterly
frequency, the potential increase in Core Damage Frequency (CDF) and risk associated with the
extension must be evaluated and determined to be small and consistent with the intent of the
Commission’s Safety Goal Policy Statement.
(4) Paragraph 4.4.1, “Acceptance Criteria,” of OMN-12 specifies that acceptance criteria must be
established for the analysis of test data for pneumatically and hydraulically operated valve
assemblies categorized as high safety significant within the scope of the code case. When
establishing these acceptance criteria, the potential degradation rate and available capability
margin for each valve assembly must be evaluated and determined to provide assurance that the
valve assemblies are capable of performing their design-basis functions until the next scheduled
test.
(5) Paragraph 5, “Low Safety Significant Valve Assemblies,” of OMN-12 specifies that the
purpose of its provisions is to provide a high degree of confidence that pneumatically and
hydraulically operated valve assemblies categorized as low safety significant within the scope
of the code case will perform their intended safety function if called upon. The applicant or
licensee must have reasonable confidence that low safety significant valve assemblies remain
capable of performing their intended design-basis safety functions until the next scheduled test.
The test and evaluation methods may be less rigorous than those applied to high safety
significant valve assemblies.
(6) Paragraph 5.1, “Set Points and/or Critical Parameters,” of OMN-12 specifies requirements and
guidance for establishing set points and critical parameters of pneumatically and hydraulically
operated valve assemblies categorized as low safety significant within the scope of the code
case. Setpoints for these valve assemblies must be based on direct dynamic test information, a
test-based methodology, or grouping with dynamically tested valves, and documented
according to Paragraph 5.1.4. The setpoint justification methods may be less rigorous than
provided for high risk significant valve assemblies.

DG-1297, Page 10

Code Case
Number

Table 2
Conditionally Acceptable OM Code Cases
Title/Condition

OMN-12
(2012 Edition)
(cont’d)

Alternative Requirements for Inservice Testing Using Risk Insights for Pneumatically and
Hydraulically Operated Valve Assemblies in Light-Water Reactor Power Plants (OM-Code 1998,
Subsection ISTC)
(7) Paragraph 5.4, “Evaluations,” of OMN-12, specifies evaluations to be performed of
pneumatically and hydraulically operated valve assemblies categorized as low safety significant
within the scope of the Code Case. Initial and periodic diagnostic testing must performed to
establish and verify the setpoints of these valve assemblies to ensure that they are capable of
performing their design-basis safety functions. Methods for testing and establishing test
frequencies may be less rigorous than applied to high risk significant valve assemblies.
(8) Paragraph 5.6, “Corrective Action,” of OMN-12 specifies that corrective action must be
initiated if the parameters monitored and evaluated for pneumatically and hydraulically
operated valve assemblies categorized as low safety significant within the scope of the code
case do not meet the established criteria. Further, if the valve assembly does not satisfy its
acceptance criteria, the operability of the valve assembly must be evaluated.
Note 1: Applicants and licensees are cautioned that, when implementing OMN-12, the benefits of
performing a particular test should be balanced against the potential adverse effects placed on the
valves or systems caused by this testing.
Note 2: Paragraph 3.1 of OMN-12 states that “Valve assemblies shall be classified as either high
safety significant or low safety significant in accordance with Code Case OMN-3.” This note as
well as Note 2 to OMN-4 has been added to ensure the consistent consideration of risk insights.
Note 3: The conditions are identical to those imposed on OMN-12 (2004 Edition) in Revision 1 to
Regulatory Guide 1.192.

OMN-16
Revision 1
(2012 Edition)

Use of A Pump Curve for Testing

OMN-18
(2012 Edition)

Alternate Testing Requirements for Pumps Tested Quarterly Within ±20% of Design Flow

Figure 1 was inadvertently omitted from OMN-16, Revision 1, in the 2012 Edition of the OM Code.
This Code Case is approved for use provided it is supplemented with Figure 1 of OMN-16 that is in
the 2006 Addendum of the OM Code.
Note: OMN-16, 2006 Addenda, was unconditionally approved in Rev. 1 of RG 1.192.

The upper end values of the Group A Test Acceptable Ranges for flow and differential pressure (or,
discharge pressure) must be 1.06Qr and 1.06ΔPr (or 1.06Pr), respectively, as applicable to the pump
type. The high values of the Required Action Ranges for flow and differential pressure (or
discharge pressure) must be >1.06Qr and >1.06ΔPr (or 1.06Pr), respectively, as applicable to the
pump type.

DG-1297, Page 11

Code Case
Number

Table 2
Conditionally Acceptable OM Code Cases
Title/Condition

OMN-19
(2012 Edition)

Alternative Upper Limit for the Comprehensive Pump Test
Applicants or licensees who use this Code Case must implement a pump periodic verification test
program. A pump periodic verification test is defined as a test that verifies a pump can meet the
required (differential or discharge) pressure as applicable, at its highest design basis accident flow
rate.
The applicant or licensee must:
(a) Identify those certain applicable pumps with specific design basis accident flow rates in the
applicant’s or licensee’s credited safety analysis (e.g., technical specifications, technical
requirements program, or updated safety analysis report) for inclusion in this program.
(b) Perform the pump periodic verification test at least once every two years.
(c) Determine whether the pump periodic verification test is required before declaring the pump
operable following replacement, repair, or maintenance on the pump.
(d) Declare the pump inoperable if the pump periodic verification test flow rate and associated
differential pressure (or discharge pressure for positive displacement pumps ) cannot be
achieved.
(e) Maintain the necessary records for the pump periodic verification tests, including the
applicable test parameters (e.g., flow rate and associated differential pressure, or flow rate and
associated discharge pressure, and speed for variable speed pumps) and their basis.
(f) Account for the pump periodic verification test instrument accuracies in the test acceptance
criteria.
The applicant or licensee need not perform a pump periodic verification test if the design basis
accident flow rate in the applicant’s or licensee’s safety analysis is bounded by the comprehensive
pump test or Group A test.

DG-1297, Page 12

3.

Code Cases Superseded by Revised Code Cases
Table 3 lists Code Cases that have been superseded by revision.
Table 3. OM Code Cases That Have Been Superseded by Revised Code Cases

Code Case Number
OMN-1
(1996 Addenda)
(1999 Addenda)
(2001 Edition)
(2002 Addenda)
(2004 Edition)
(2006 Addenda)
(2009 Edition)

Table 3
Code Cases That Have Been Superseded by Revised Code Cases
Alternative Rules for Preservice and Inservice Testing of Certain Motor-Operated Valve
Assemblies in Light-Water Reactor Power Plants (OM Code-1995, Subsection ISTC)
Licensees may use this Code Case in lieu of the provisions for stroke-time testing in Subsection
ISTC of the 1995 Edition up to and including the 2000 Addenda of the ASME OM Code when
applied in conjunction with the provisions for leakage rate testing in, as applicable, ISTC 4.3
(1995 Edition with the 1996 and 1997 Addenda) and ISTC-3600 (1998 Edition through the 2004
Addenda). In addition, licensees who continue to implement Section XI of the ASME BPV Code
as their Code of Record may use OMN-1 in lieu of the provisions for stroke-time testing specified
in Paragraph 4.2.1 of ASME/ANSI OM Part 10 as required by 10 CFR 50.55a(b)(2)(vii) subject to
the conditions in this regulatory guide. Licensees who choose to apply OMN-1 must apply all its
provisions.
(1) The adequacy of the diagnostic test interval for each motor-operated valve (MOV) must be
evaluated and adjusted as necessary, but not later than 5 years or three refueling outages
(whichever is longer) from initial implementation of OMN-1.
(2) When extending exercise test intervals for high risk MOVs beyond a quarterly frequency,
licensees must ensure that the potential increase in Core Damage Frequency (CDF) and risk
associated with the extension is small and consistent with the intent of the Commission’s
Safety Goal Policy Statement.
(3) When applying risk insights as part of the implementation of OMN-1, licensees must
categorize MOVs according to their safety significance using the methodology described in
Code Case OMN-3, “Requirements for Safety Significance Categorization of Components
Using Risk Insights for Inservice Testing of LWR Power Plants,” with the conditions
discussed in this regulatory guide or use other MOV risk-ranking methodologies accepted by
the NRC on a plant-specific or industry-wide basis with the conditions in the applicable
safety evaluations.
NOTE: As indicated at 64 FR 51370-51386, licensees are cautioned that, when implementing
OMN-1, the benefits of performing a particular test should be balanced against the potential
adverse effects placed on the valves or systems caused by this testing.

OMN-2
(1998 Addenda)
(2001 Edition)
(2004 Edition)
(2009 Edition)

Thermal Relief Valve Code Case, OM Code-1995, Appendix I

DG-1297, Page 13

Code Case Number
OMN-3
(1998 Edition)
(2001 Edition)
(2002 Addenda)
(2004 Edition)
(2009 Edition)

Table 3
Code Cases That Have Been Superseded by Revised Code Cases
Requirements for Safety Significance Categorization of Components Using Risk Insights for
Inservice Testing of LWR Power Plants
(1) In addition to those components identified in the ASME IST Program Plan, implementation
of Section 1, “Applicability,” of the Code Case must include within the scope of a licensee’s
risk-informed IST program non-ASME Code components categorized as high safety
significant components (HSSCs) that might not currently be included in the IST Program
Plan.
(2) The decision criteria discussed in Section 4.4.1, “Decision Criteria,” of the Code Case for
evaluating the acceptability of aggregate risk effects (i.e., for Core Damage Frequency
[CDF] and Large Early Release Frequency [LERF]) must be consistent with the guidance
provided in Regulatory Guide 1.174, “An Approach for Using Probabilistic Risk Assessment
in Risk-Informed Decisions on Plant-Specific Changes to the Licensing Basis.”
(3) Section 4.4.4, “Defense in Depth,” of the Code Case must be consistent with the guidance
contained in Sections 2.2.1, “Defense-in-Depth Evaluation,” and 2.2.2, “Safety Margin
Evaluation,” of Regulatory Guide 1.175, “An Approach for Plant-Specific, Risk-Informed
Decisionmaking: Inservice Testing.”
(4) Implementation of Sections 4.5, “Inservice Testing Program,” and 4.6, “Performance
Monitoring,” of the Code Case must be consistent with the guidance pertaining to inservice
testing of pumps and valves provided in Section 3.2, “Program Implementation,” and Section
3.3, “Performance Monitoring,” of Regulatory Guide 1.175. Testing and performance
monitoring of individual components must be performed as specified in the risk-informed
components Code Cases (e.g., OMN-1, OMN-4, OMN-7, and OMN-12, as modified by the
conditions discussed in this regulatory guide).
Note: The Code Case methodology for risk ranking uses two categories of safety significance.
The NRC staff has determined that this is acceptable for ranking MOVs, air-operated valves
(AOVs), and check valves. However, the NRC staff has accepted other methodologies for risk
ranking MOVs, with certain conditions, that use three categories of safety significance.

OMN-4
(1999 Addenda)
(2001 Edition)
(2004 Edition)
(2009 Edition)

Requirements for Risk Insights for Inservice Testing of Check Valves at LWR Power Plants

(1) Valve opening and closing functions must be demonstrated when flow testing or examination
methods (nonintrusive, or disassembly and inspection) are used.
(2) The initial interval for tests and associated examinations may not exceed two fuel cycles or 3
years, whichever is longer; any extension of this interval may not exceed one fuel cycle per
extension with the maximum interval not to exceed 10 years. Trending and evaluation of
existing data must be used to reduce or extend the time interval between tests.
(3) If the Appendix II condition monitoring program is discontinued, the requirements of ISTC
4.5.1, “Exercising Test Frequency,” through ISTC 4.5.4, “Valve Obturator Movement,” (1996
and 1997 Addenda) or ISTC 3510, 3520, 3540, and 5221 (1998 Edition with the 1999 and
2000 Addenda), as applicable, must be implemented.

DG-1297, Page 14

Code Case Number

Table 3
Code Cases That Have Been Superseded by Revised Code Cases

OMN-5
(1999 Addenda)
(2001 Edition)
(2004 Edition)
(2006 Addenda)
(2009 Edition)

Testing of Liquid Service Relief Valves Without Insulation

OMN-6
(1999 Addenda)
(2001 Edition)
(2002 Addenda)
(2004 Edition)
(2006 Addenda)
(2009 Edition)

Alternate Rules for Digital Instruments

OMN-7
(2000 Addenda)
(2001 Edition)
(2002 Addenda)
(2004 Edition)
(2005 Addenda)
(2006 Addenda)
(2009 Edition)

Alternative Requirements for Pump Testing

OMN-8
(2000 Addenda)
(2001 Edition)
(2003 Addenda)
(2004 Edition)
(2005 Addenda)
(2006 Addenda)
(2009 Edition)

Alternative Rules for Preservice and Inservice Testing of Power-Operated Valves That Are Used
for System Control and Have a Safety Function per OM-10, ISTC-1.1, or ISTA-1100

OMN-9
(2000 Addenda)
(2001 Edition)
(2003 Addenda)
(2004 Edition)
(2009 Edition)

Use of a Pump Curve for Testing
(1) When a reference curve may have been affected by repair, replacement, or routine servicing
of a pump, a new reference curve must be determined, or an existing reference curve must be
reconfirmed, in accordance with Section 3 of this Code Case.
(2) If it is necessary or desirable, for some reason other than that stated in Section 4 of this Code
Case, to establish an additional reference curve or set of curves, these new curves must be
determined in accordance with Section 3.

DG-1297, Page 15

Code Case Number

Table 3
Code Cases That Have Been Superseded by Revised Code Cases
Title/Condition

OMN-11
(2001 Edition)
(2003 Addenda)
(2004 Edition)
(2006 Addenda)
(2009 Edition)

Risk-Informed Testing for Motor-Operated Valves
Where a licensee is implementing Code Case OMN-1 as a justified alternative to the requirements
for stroke-time testing of motor-operated valves (MOVs) in Subsection ISTC of the ASME OM
Code, the licensee may apply risk insights to its MOV program as indicated in Paragraph 3.7,
“Risk Based Criteria for MOV Testing,” of OMN-1 and as supplemented by Code Case OMN-11
with the following conditions:
(1) In addition to the Inservice Testing provisions of Paragraph 3 of OMN-11, MOVs within the
scope of OMN-1 that are categorized as Low Safety Significant Components (LSSCs) must
satisfy the other provisions of OMN-1, including determination of proper MOV test intervals
as specified in Paragraph 6 of OMN-1.
(2) Paragraph 3(a) of OMN-11 must be interpreted as allowing the provisions of
Paragraphs 3.5(a) and (d) of OMN-1 related to similarity and test sample, respectively, to be
relaxed for the grouping of LSSC MOVs. The provisions of Paragraphs 3.5(b), (c), and (e) of
OMN-1, related to evaluation of test results for MOVs in the group, sequential testing of a
representative MOV, and analysis of test results per Paragraph 6 of OMN-1 for each MOV in
the group, respectively, continue to be applicable to all MOVs within the scope of OMN-1.
(3) When extending exercise test intervals for high risk MOVs beyond a quarterly frequency, the
licensee must ensure that the potential increase in CDF and risk associated with the extension
is small and consistent with the intent of the Commission’s Safety Goal Policy Statement.
Note 1: Condition regarding allowable methodologies for MOV risk ranking specified for the use
of OMN-1 also applies to OMN-11.

OMN-12
(2001 Edition)
(2004 Edition)
(2009 Edition)

Alternative Requirements for Inservice Testing Using Risk Insights for Pneumatically and
Hydraulically Operated Valve Assemblies in Light-Water Reactor Power Plants (OM-Code 1998,
Subsection ISTC)
(1) Paragraph 4.2, “Inservice Test Requirements,” of OMN-12 specifies inservice test
requirements for pneumatically and hydraulically operated valve assemblies categorized as
high safety significant within the scope of the Code Case. The inservice testing program must
include a mix of static and dynamic valve assembly performance testing. The mix of valve
assembly performance testing may be altered when justified by an engineering evaluation of
test data.
(2) Paragraph 4.2.2.3 of OMN-12 specifies the periodic test requirements for pneumatically and
hydraulically operated valve assemblies categorized as high safety significant within the
scope of the code case. The adequacy of the diagnostic test interval for each high safety
significant valve assembly must be evaluated and adjusted as necessary, but not later than
5 years or three refueling outages (whichever is longer) from initial implementation of OMN12.
(3) Paragraph 4.2.3, “Periodic Valve Assembly Exercising,” of OMN-12 specifies periodic
exercising for pneumatically and hydraulically operated valve assemblies categorized as high
safety significant within the scope of the code case. Consistent with the requirement in
OMN-3 to evaluate the aggregate change in risk associated with changes in test strategies,
when extending exercise test intervals for high safety significant valve assemblies beyond a
quarterly frequency, the potential increase in Core Damage Frequency (CDF) and risk
associated with the extension must be evaluated and determined to be small and consistent
with the intent of the Commission’s Safety Goal Policy Statement.

DG-1297, Page 16

Code Case Number
OMN-12
(2001 Edition)
(2004 Edition)
(2009 Edition)
(continued)

Table 3
Code Cases That Have Been Superseded by Revised Code Cases
Alternative Requirements for Inservice Testing Using Risk Insights for Pneumatically and
Hydraulically Operated Valve Assemblies in Light-Water Reactor Power Plants OM-Code 1998,
Subsection ISTC)
(4) Paragraph 4.4.1, “Acceptance Criteria,” of OMN-12 specifies that acceptance criteria must be
established for the analysis of test data for pneumatically and hydraulically operated valve
assemblies categorized as high safety significant within the scope of the code case. When
establishing these acceptance criteria, the potential degradation rate and available capability
margin for each valve assembly must be evaluated and determined to provide assurance that
the valve assemblies are capable of performing their design-basis functions until the next
scheduled test.
(5) Paragraph 5, “Low Safety Significant Valve Assemblies,” of OMN-12 specifies that the
purpose of its provisions is to provide a high degree of confidence that pneumatically and
hydraulically operated valve assemblies categorized as low safety significant within the scope
of the code case will perform their intended safety function if called upon. The licensee must
have reasonable confidence that low safety significant valve assemblies remain capable of
performing their intended design-basis safety functions until the next scheduled test. The test
and evaluation methods may be less rigorous than those applied to high safety significant
valve assemblies.
(6) Paragraph 5.1, “Set Points and/or Critical Parameters,” of OMN-12 specifies requirements
and guidance for establishing set points and critical parameters of pneumatically and
hydraulically operated valve assemblies categorized as low safety significant within the scope
of the code case. Setpoints for these valve assemblies must be based on direct dynamic test
information, a test-based methodology, or grouping with dynamically tested valves, and
documented according to Paragraph 5.1.4. The setpoint justification methods may be less
rigorous than provided for high risk significant valve assemblies.
(7) Paragraph 5.4, “Evaluations,” of OMN-12 specifies evaluations to be performed of
pneumatically and hydraulically operated valve assemblies categorized as low safety
significant within the scope of the code case. Initial and periodic diagnostic testing must be
performed to establish and verify the setpoints of these valve assemblies to ensure that they
are capable of performing their design-basis safety functions. Methods for testing and
establishing test frequencies may be less rigorous than applied to high risk significant valve
assemblies.
(8) Paragraph 5.6, “Corrective Action,” of OMN-12 specifies that corrective action must be
initiated if the parameters monitored and evaluated for pneumatically and hydraulically
operated valve assemblies categorized as low safety significant within the scope of the code
case do not meet the established criteria. Further, if the valve assembly does not satisfy its
acceptance criteria, the operability of the valve assembly must be evaluated.
Note: Licensees are cautioned that, when implementing OMN-12, the benefits of performing a
particular test should be balanced against the potential adverse effects placed on the valves or
systems caused by this testing.

OMN-13
(2001 Edition)
(2004 Edition)
(2009 Edition)
(2012 Edition

Requirements for Extending Snubber Inservice Visual Examination Interval at LWR Power Plants

DG-1297, Page 17

Code Case Number

Table 3
Code Cases That Have Been Superseded by Revised Code Cases

OMN-13
Revision 1
(2009 Edition)
(2012 Edition)

Requirements for Extending Snubber Inservice Visual Examination Interval at LWR Power Plants

OMN-13
Revision 2
(2009 Edition)

Performance-Based Requirements for Extending Snubber Inservice Visual Examination Interval
at LWR Power Plants

OMN-14
(2003 Addenda)
(2004 Edition)
(2009 Edition)

Alternative Rules for Valve Testing Operations and Maintenance, Appendix I: BWR CRD Rupture
Disk Exclusion

OMN-15
(2004 Edition)

Performance-Based Requirements for Extending the Snubber Operational Readiness Testing
Interval at LWR Power Plants

OMN-15
Revision 2
(2011 Addenda)

Performance-Based Requirements for Extending the Snubber Operational Readiness Testing
Interval at LWR Power Plants

OMN-16
(2006 Addenda)
(2009 Edition)
(2012 Edition)

Use of A Pump Curve for Testing

OMN-17
(2009 Edition)

Alternative Rules for Testing ASME Class 1 Pressure Relief/Safety Valves

OMN-18
(2009 Edition)

Alternate Testing Requirements for Pumps Testing Quarterly Within ±20% of Design Flow

OMN-19
(2011 Addenda)

Alternative Upper Limit for the Comprehensive Pump Test

DG-1297, Page 18

D. IMPLEMENTATION
The purpose of this section is to provide information to applicants and licensees
regarding the NRC staff’s plans for using this regulatory guide. The requirements addressing
implementation of OM Code Cases are contained in 10 CFR 50.55a(b)(6). No backfitting is
intended or approved in connection with the issuance of this guide.

REGULATORY ANALYSIS
A separate regulatory analysis was not prepared for this regulatory guide. The regulatory
basis for this guide is the regulatory analysis prepared for the amendment to 10 CFR 50.55a,
“Codes and Standards,” which incorporates this regulatory guide by reference.

DG-1297, Page 19

REFERENCES1
1.

ASME Code for Operation and Maintenance of Nuclear Power Plants, American Society of
Mechanical Engineers, New York, NY.2

2.

Code of Federal Regulations, Title 10, Energy, Part 50, “Domestic Licensing of Production and
Utilization Facilities” (10 CFR Part 50), U.S. Nuclear Regulatory Commission, Washington, DC.

3.

Regulatory Guide 1.84, “Design, Fabrication, and Materials Code Case Acceptability, ASME
Section III,” U.S. Nuclear Regulatory Commission, Washington, DC.

4.

Regulatory Guide 1.147, “Inservice Inspection Code Case Acceptability, ASME Section XI,
Division 1,” U.S. Nuclear Regulatory Commission, Washington, DC.

5.

Regulatory Guide 1.193, “ASME Code Cases Not Approved for Use,” U.S. Nuclear Regulatory
Commission, Washington, DC.

6.

Paperwork Reduction Act of 1995 (Public Law 104-13), United States Code, Title 44,
“Public Printing and Documents,” Chapter 35, “Coordination of Federal Information Policy”
(44 U.S.C. 3501 et seq.), 104th Congress of the United States of America, Washington, DC.3

7.

Regulatory Guide 1.174, “An Approach for Using Probabilistic Risk Assessment in RiskInformed Decisions on Plant-Specific Changes to the Licensing Basis,” U.S. Nuclear Regulatory
Commission, Washington, DC.

8.

Regulatory Guide 1.175, “An Approach for Plant-Specific, Risk-Informed Decisionmaking:
Inservice Testing,” U.S. Nuclear Regulatory Commission, Washington, DC.

9.

Regulatory Guide 1.200, “An Approach for Determining the Technical Adequacy of Probabilistic
Risk Assessment Results for Risk-Informed Activities,” U.S. Nuclear Regulatory Commission,
Washington, DC.

10.

Regulatory Guide 1.201, “Guidelines for Categorizing Structures, Systems, and Components in
Nuclear Power Plants According to their Safety Significance,” U.S. Nuclear Regulatory
Commission, Washington, DC.

1

Publicly available NRC published documents are available electronically through the NRC Library on the NRC’s
public Web site at: http://www.nrc.gov/reading-rm/doc-collections/. The documents can also be viewed on-line or
printed for a fee in the NRC’s Public Document Room (PDR) at 11555 Rockville Pike, Rockville, MD; the mailing
address is USNRC PDR, Washington, DC 20555; telephone 301-415-4737 or (800) 397-4209; fax (301) 415-3548; and
e-mail pdr.resource@nrc.gov.

2

Copies may be purchased from the American Society of Mechanical Engineers, Three Park Avenue, New York, NY
10016-5990; phone (212) 591-8500; fax (212) 591-8501; www.asme.org.

3

The Paperwork Reduction Act of 1995 (44 U.S.C. 3501 et seq.) is available electronically through the Federal Register
Web site administered by the U.S. National Archives and Records Administration, at http://www.archives.gov/ federalregister/laws/paperwork-reduction/

DG-1297, Page 20

APPENDIX A
NUMERICAL LISTING OF OPERATION AND MAINTENANCE
CODE CASES
Code Case

1

2

ASME
Action
Regarding
Code Case

Year Code Case
Developed/Revised

Code Case Approved
Table Where Code
in RG 1.192 (Y/N) /
Case Listed in
Which Revision of
Revision 2 of RG 1.192
RG 1.192

OMN-1

New
Reaffirmed1
Reaffirmed
Revised
Reaffirmed
Revised
Reaffirmed
Reaffirmed

1996 Addenda
1999 Addenda
2001 Edition
2002 Addenda
2004 Edition
2006 Addenda
2009 Edition
2012 Edition

50.55a2
Y / Revision 0
N
N
N
Y / Revision 1
N
N

All versions of OMN-1
are listed in Table 3

OMN-1,
Revision 1

New
Reaffirmed

2009 Edition
2012 Edition

N
Y / Revision 2

Table 3
Table 2

OMN-2

New
Reaffirmed
Reaffirmed
Reaffirmed
Reaffirmed

1998 Edition
2001 Edition
2004 Edition
2009 Edition
2012 Edition

Y / Revision 0
N
Y / Revision 1
N
Y / Revision 2

Table 3
Table 3
Table 3
Table 3
Table 1

OMN-3

New
Reaffirmed
Revised
Reaffirmed
Reaffirmed
Reaffirmed

1998 Edition
2001 Edition
2002 Addenda
2004 Edition
2009 Edition
2012 Edition

Y/ Revision 0
N
N
Y / Revision 1
N
Y / Revision 2

Table 3
Table 3
Table 3
Table 3
Table 3
Table 2

OMN-4

New
Reaffirmed
Reaffirmed
Reaffirmed
Reaffirmed

1999 Addenda
2001 Edition
2004 Edition
2009 Edition
2012 Edition

Y/ Revision 0
N
Y / Revision 1
N
Y / Revision 2

Table 3
Table 3
Table 3
Table 3
Table 2

OMN-5

New
Reaffirmed
Reaffirmed
Reaffirmed
Reaffirmed
Reaffirmed

1999 Addenda
2001 Edition
2004 Edition
2006 Addenda
2009 Edition
2012 Edition

Y / Revision 0
N
N
Y / Revision 1
N
Y / Revision 2

Table 3
Table 3
Table 3
Table 3
Table 3
Table 1

Note pertaining to reaffirmed Code Cases: In some cases, clarifications or editorial changes were made in reaffirmed
Code Cases, and notations regarding where those changes occurred may not have been provided with the Code Case.
OMN-1, 1996 Addenda, was approved directly in 10 CFR 50.55a

Appendix A to DG-1297, Page A-1

Code Case

ASME
Action
Regarding
Code Case

Year Code Case
Developed/Revised

Code Case Approved
Table Where Code
in RG 1.192 (Y/N) /
Case Listed in
Which Revision of
Revision 2 of RG 1.192
RG 1.192

OMN-6

New
Reaffirmed
Reaffirmed
Reaffirmed
Revised
Reaffirmed
Reaffirmed

1999 Addenda
2001 Edition
2002 Addenda
2004 Edition
2006 Addenda
2009 Edition
2012 Edition

Y/ Revision 0
N
N
N
Y/ Revision 1
N
Y / Revision 2

Table 3
Table 3
Table 3
Table 3
Table 3
Table 3
Table 1

OMN-7

New
Reaffirmed
Reaffirmed
Reaffirmed
Reaffirmed
Reaffirmed
Reaffirmed
Reaffirmed

2000 Addenda
2001 Edition
2002 Addenda
2004 Edition
2005 Addenda
2006 Addenda
2009 Edition
2012 Edition

Y/ Revision 0
N
N
N
N
Y / Revision 1
N
Y / Revision 2

Table 3
Table 3
Table 3
Table 3
Table 3
Table 3
Table 3
Table 1

OMN-8

New
Reaffirmed
Reaffirmed
Reaffirmed
Reaffirmed
Revised
Reaffirmed
Reaffirmed

2000 Addenda
2001 Edition
2003 Addenda
2004 Edition
2005 Addenda
2006 Addenda
2009 Edition
2012 Edition

Y/ Revision 0
N
N
N
N
Y / Revision 1
N
Y / Revision 2

Table 3
Table 3
Table 3
Table 3
Table 3
Table 3
Table 3
Table 1

OMN-9

New
Reaffirmed
Reaffirmed
Reaffirmed
Reaffirmed
Reaffirmed

2000 Addenda
2001 Edition
2003 Addenda
2004 Edition
2009 Edition
2012 Edition

Y/ Revision 0
N
N
Y / Revision 1
N
Y / Revision 2

Table 3
Table 3
Table 3
Table 3
Table 3
Table 2

OMN-10

New
Reaffirmed
Reaffirmed
Reaffirmed
Reaffirmed
Reaffirmed
Reaffirmed

2000 Addenda
2001 Edition
2003 Addenda
2004 Edition
2006 Addenda
2009 Edition
2012 Edition

N
N
N
N
N
N
N

Code Case OMN-10 has
not been approved for
use and is listed in
RG 1.193

OMN-112

New
Reaffirmed
Reaffirmed

2001 Edition
2003 Addenda
2004 Edition

Y / Revision 0
Y / Revision 1
Y / Revision 1

Table 3
Table 3
Table 3

2
Code Case OMN-11 in the 2006 Addenda, 2009 Edition, and 2012 Edition to the ASME OM Code is no longer applicable because the
requirements of Code Case OMN-11 have been merged into Code Case OMN-1.

Appendix A to DG-1297, Page A-2

Code Case

ASME
Action
Regarding
Code Case

Year Code Case
Developed/Revised

Code Case Approved
Table Where Code
in RG 1.192 (Y/N) /
Case Listed in
Which Revision of
Revision 2 of RG 1.192
RG 1.192

OMN-12

New
Reaffirmed
Reaffirmed
Reaffirmed

2001 Edition
2004 Edition
2009 Edition
2012 Edition

Y / Revision 0
Y / Revision 1
N
Y / Revision 2

Table 3
Table 3
Table 3
Table 2

OMN-13

New
Reaffirmed
Reaffirmed
Reaffirmed
Reaffirmed

2001 Edition
2001 Edition
2004 Edition
2009 Edition
2012 Edition

Y/ Revision 0
N
Y / Revision 1
N
N

All versions of OMN-13
are listed in Table 3

OMN-13,
Revision 1

New
Reaffirmed

2009 Edition
2012 Edition

N
N

All versions of OMN13, Revision 1, are listed
in Table 3

OMN-13,
Revision 2

New
Reaffirmed

2009 Edition
2012 Edition

N
Y / Revision 2

Table 3
Table 1

OMN-14

New
Reaffirmed
Reaffirmed
Reaffirmed

2003 Addenda
2004 Edition
2009 Edition
2012 Edition

N
Y / Revision 1
N
Y / Revision 2

Table 3
Table 3
Table 3
Table 1

OMN-15

New
Revised
Reaffirmed
Reaffirmed

2004 Edition
2006 Addenda
2009 Edition
2012 Edition

N
N
N
N

Code Case OMN-15 has
not been approved for
use and is listed in RG
1.193

OMN-15,
New
Revision 23 Reaffirmed

2011 Addenda
2012 Edition

N
Y / Revision 2

Table 3
Table 1

OMN-16

New
Reaffirmed
Reaffirmed

2006 Addenda
2009 Edition
2012 Edition

Y / Revision 1
N
N

Table 3
Table 3
Table 3

OMN-16,
Revision 1

New

2012 Edition

Y / Revision 2

Table 2

OMN-17

New
Reaffirmed

2009 Edition
2012 Edition

N
Y / Revision 2

Table 3
Table 1

OMN-18

New
Reaffirmed

2009 Edition
2012 Edition

N
Y / Revision 2

Table 3
Table 2

OMN-19

New
Reaffirmed

2011 Addenda
2012 Edition

N
Y / Revision 2

Table 3
Table 2

OMN-20

New

2012 Edition

Y / Revision 2

Table 1

3 It should be noted that a different number convention was used with respect to OMN-15; Revision 1 to this Code Case does not exist.

Appendix A to DG-1297, Page A-3