This guide was issued after consideration of comments received from the public. Comments and suggestions for improvements in these guides are

encouraged at all times, and guides will be revised, as appropriate, to accommodate comments and to reflect new information or experience. Written

comments may be submitted to the Rules and Directives Branch, ADM, U.S. Nuclear Regulatory Commission, DC 20555-0001.

Regulatory guides are issued in ten broad divisions: 1, Power Reactors; 2, Research and Test Reactors; 3, Fuels and Materials Facilities; 4,

Environmental and Siting; 5, Materials and Plant Protection; 6, Products; 7, Transportation; 8, Occupational Health; 9, Antitrust and Financial

Review; and 10, General.

Single copies of regulatory guides (which may be reproduced) may be obtained free of charge by writing the Distribution Services Section, U.S.

Nuclear Regulatory Commission, Washington, DC 20555-0001, or by fax to (301)415-2289; or by email to DISTRIBUTION@NRC.GOV.

Electronic copies of this guide are available on the Internet at NRC’s web site at <WWW.NRC.GOV> in the Reference Library under Regulatory

Guides. This guide is also available in the Electronic Reading Room at NRC’s home page, along with other recently issued guides, Accession Number

ML030730430.

 U.S. NUCLEAR REGULATORY COMMISSION June 2003

 REGULATORY GUIDE

 OFFICE OF NUCLEAR REGULATORY RESEARCH

REGULATORY GUIDE 1.192

(Draft was issued as DG-1089)

OPERATION AND MAINTENANCE CODE CASE ACCEPTABILITY,

ASME OM CODE

A. INTRODUCTION

General Design Criterion (GDC) 1, “Quality Standards and Records,“ of Appendix A,

“General Design Criteria for Nuclear Power Plants,” to 10 CFR Part 50, “Domestic Licensing

of Production and Utilization Facilities,” 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 functions 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.

Provisions of the American Society of Mechanical Engineers (ASME) Boiler and

Pressure Vessel (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. ASME standards

committees develop, among other things, 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.

The NRC has committed through its Strategic Plan to use consensus standards to

increase public involvement in the NRC’s regulatory development process, consistent with the

provisions of Public Law 104-113, the National Technology and Transfer Act of 1995, and

Office of Management and Budget (OMB) Circular A-119, “Federal Participation in the

Development and Use of Voluntary Consensus Standards and Conformity Assessment.” To

further the NRC’s commitment in the Strategic Plan and because ASME Code provisions
1 Copies may be obtained 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.

2

have played a significant role in the regulatory process, the NRC has through this guide

endorsed for the first time ASME Operation and Maintenance (OM) Code Cases.

In 1990, the ASME published the initial edition of the OM Code, which provides

rules for IST of pumps and valves. The OM Code was developed and is maintained by

the ASME Committee on Operation and Maintenance of Nuclear Power Plants (ASME

OM Committee). 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 of pumps and valves 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 of pumps and valves, and the

Section XI rules for IST of pumps and valves 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).

Section 50.55a(f), “Inservice Testing Requirements,” requires, in part, that Class 1,

2, and 3 components and their supports meet the requirements of the “Code for Operation

and Maintenance of Nuclear Power Plants,”

1

 of the ASME OM Code or equivalent quality

standards. The ASME publishes a new edition of the OM Code every three years, and

new addendum every year. 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(b). The ASME also

publishes OM Code Cases yearly. Code Cases provide alternatives developed and

approved by ASME or explain the intent of existing Code requirements. This regulatory

guide identifies the Code Cases that have been determined by the NRC to be acceptable

alternatives to applicable parts of the OM Code. In the past, the acceptability of Code

Cases related to Section XI rules for IST of pumps and valves were addressed in

Regulatory Guide 1.147, “Inservice Inspection Code Case Acceptability, ASME Section

XI, Division 1.” With the endorsement of the OM Code, the NRC determined that it was

appropriate to develop this new guide for endorsement of Code Cases related to the OM

Code. These Code Cases may be used by licensees, without request to the NRC,

provided they are used with any identified limitations or modifications. OM Code Cases

not yet endorsed by the NRC may be implemented through 10 CFR 50.55a(a)(3), which

permits the use of alternatives to the Code requirements referenced in 10 CFR 50.55a

provided the proposed alternatives result in an acceptable level of quality and safety and

provided their use is authorized by the Director of the Office of Nuclear Reactor

Regulation.

The ASME Code is incorporated by reference into 10 CFR 50.55a. Code Cases

approved by the NRC provide an acceptable voluntary alternative to the mandatory ASME

Code provisions. 10 CFR 50.55a has been amended to incorporate this guide by

reference and states the requirements governing the use of Code Cases. Because of the

continuing change in the status of Code Cases, periodic updates to 10 CFR 50.55a and

this guide are planned to accommodate new Code Cases and any revisions of existing

Code Cases.

This regulatory guide does not contain a new or amended information collection

requirement subject to the Paperwork Reduction Act of 1995 (44 U.S.C. 3501 et seq.). 
3

Existing requirements were approved by the Office of Management and Budget, and the

approval number is 3150-0011. If a means used to impose an information collection does

not display a currently valid OMB control number, the NRC may not conduct or sponsor,

and a person is not required to respond to, the information collection.

B. DISCUSSION

This regulatory guide lists the OM Code Cases that are acceptable to the NRC for

implementation in the IST of light-water-cooled nuclear power plants. The NRC staff

reviewed Code Cases OMN-1 through OMN-13 for inclusion in this guide. Appendix A

lists the OM Code edition or addenda for each Code Case, with the date of approval by

the ASME Board on Nuclear Codes and Standards. Appendix B is a numerical listing of

the OM Code Cases. In the Regulatory Position, Table 1, “Acceptable OM Code Cases,”

lists the Code Cases that are acceptable to the NRC for implementation in the IST of lightwater cooled nuclear power plants. Table 2, “Conditionally Acceptable OM Code Cases,”

lists the Code Cases that are acceptable provided they are used with the identified

limitations or modifications, i.e., the Code Case is generally acceptable but the NRC has

determined that the alternative requirements must be supplemented in order to provide an

acceptable level of quality and safety. OM Code Cases that the NRC has determined to

be unacceptable are listed in Regulatory Guide 1.193 (DG-1112), “ASME Code Cases

Not Approved for Use.”

Code Cases provide alternatives that were developed and approved by ASME to

existing Code requirements. The Code Cases listed as approved in Tables 1 and 2 of this

guide have been incorporated by reference into 10 CFR 50.55a. The Code Cases may

be used voluntarily by licensees as an alternative to compliance with ASME Code

provisions that have been incorporated by reference into 10 CFR 50.55a.

Requirements related to implementation of Code Cases are provided in 10 CFR

50.55a(b). When a licensee initially applies a Code Case listed in Table 1 or 2, the

licensee shall implement the most recent version of that Code Case incorporated by

reference in 10 CFR 50.55a. If a licensee has previously implemented a Code Case and

a later version of the Code Case is incorporated by reference in 10 CFR 50.55a, the

licensee may continue to apply, to the end of the current 120-month interval, the previous

version of the Code Case as authorized or may apply a later version including any

specified condition placed on its use. A licensee choosing to continue to apply the Code

Case during the subsequent 120-month interval shall implement the latest version of the

Code Case incorporated by reference in 10 CFR 50.55a (listed in Table 1 or 2) that is in

effect at the start of the interval. Notwithstanding these requirements, the Commission

may impose new or revised Code requirements, including implementation schedules, that

it determines are consistent with the backfit rule (i.e., 10 CFR 50.109).

Code Cases may expire or 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

inadequate. After a Code Case is annulled and 10 CFR 50.55a and this guide are

amended, licensees may not implement that Code Case for the first time. However, a

licensee who implemented the Code Case prior to annulment may continue to use that

Code Case through the end of the present 120-month IST program interval unless 10

CFR 50.55a specifically prohibits further use of the annulled Code Case. An annulled

Code Case cannot be used in the subsequent 120-month IST program interval unless
4

implemented as an approved alternative under 10 CFR 50.55a(a)(3). 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. 

Licensees should not begin to implement such annulled Code Cases in advance of the

rulemaking.

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. REGULATORY POSITION

1. ACCEPTABLE CODE CASES

The Code Cases listed in the table below are acceptable to the NRC for application

in licensee’s OM IST programs. Note: the ASME issues OM Code Cases once each year

when a new edition or addenda of the OM Code is published. To assist users of the OM

Code, Column 3 of Table 1 lists the edition or addenda to which each Code Case was

attached (E denotes edition; A denotes addenda), and whether the Code Case is new or

reaffirmed.

TABLE 1 - ACCEPTABLE OM CODE CASES

CODE CASE

NUMBER

TABLE 1, ACCEPTABLE OM CODE CASES EDITION/

ADDENDA

OMN-2, Rev. 0 Thermal Relief Valve Code Case New 1998E

OMN-5, Rev. 0 Testing of Liquid Service Relief Valves Without Insulation New 1999A

OMN-6, Rev. 0 Alternate Rules for Digital Instruments New 1999A

OMN-7, Rev. 0 Alternative Requirements for Pump Testing New 2000A

OMN-8, Rev. 0 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

New 2000A

OMN-13, Rev. 0 Requirements for Extending Snubber Inservice Visual

Examination Interval at LWR Power Plants

New 2000A
5

2. CONDITIONALLY ACCEPTABLE CODE CASES

The Code Cases listed in Table 2 are acceptable to the NRC for application in

licensee’s OM IST programs within the limitations indicated by the NRC. Unless

otherwise stated, limitations indicated by the NRC are in addition to the conditions

specified in the Code Case. Note that the ASME issues OM Code Cases once each year

when a new edition or addenda of the OM Code is published. To assist users of the OM

Code, Column 3 of Table 2 lists the edition or addenda to which each Code Case was

attached (E denotes edition; A denotes addenda), and whether the Code Case is new or

reaffirmed.

TABLE 2, CONDITIONALLY ACCEPTABLE OM CODE CASES

CODE CASE

NUMBER

TABLE 2, CONDITIONALLY ACCEPTABLE 

OM CODE CASES

EDITION/

ADDENDA

CONDITION

OMN-1, Rev. 0 Alternative Rules for Preservice and Inservice Testing of Certain

Motor-Operated Valve Assemblies in Light-Water Reactor Power

Plants 

Reaffirmed

1999A

Licensees may use Code Case OMN-1, "Alternative Rules for

Preservice and Inservice Testing of Certain Electric

Motor-Operated Valve Assemblies in Light-Water Reactor

Power Plants," Revision 0, 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 with

the 1999 and 2000 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. 
CODE CASE

NUMBER

TABLE 2, CONDITIONALLY ACCEPTABLE 

OM CODE CASES

EDITION/

ADDENDA

CONDITION

2

 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

and limitations, that use three categories of safety significance.

6

OMN-1, Rev. 0

(Continued)

Alternative Rules for Preservice and Inservice Testing of Certain

Motor-Operated Valve Assemblies in Light-Water Reactor Power

Plants

Reaffirmed

1999A

(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 riskranking methodologies accepted by the NRC on a plantspecific 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-3, Rev. 0 Requirements for Safety Significance Categorization of

Components Using Risk Insights for Inservice Testing of LWR

Power Plants

New

1998E

(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 categorized2

 as high safety significant

components (HSSCs) that might not currently be included in

the IST Program Plan.
CODE CASE

NUMBER

TABLE 2, CONDITIONALLY ACCEPTABLE 

OM CODE CASES

EDITION/

ADDENDA

CONDITION

7

OMN-3, Rev. 0

(continued)

Requirements for Safety Significance Categorization of

Components Using Risk Insights for Inservice Testing of LWR

Power Plants

New

1998E

(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 PlantSpecific 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 riskinformed components Code Cases (e.g., OMN-1, OMN-4,

OMN-7, and OMN-12, as modified by the conditions

discussed in this regulatory guide).

OMN-4, Rev. 0 Requirements for Risk Insights for Inservice Testing of Check

Valves at LWR Power Plants

New

1999A

(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.
CODE CASE

NUMBER

TABLE 2, CONDITIONALLY ACCEPTABLE 

OM CODE CASES

EDITION/

ADDENDA

CONDITION

8

OMN-4, Rev. 0

(continued)

Requirements for Risk Insights for Inservice Testing of Check

Valves at LWR Power Plants

New

1999A

(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.

OMN-9, Rev. 0 Use of a Pump Curve for Testing New

2000A

(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.

OMN-11,

Rev. 0

Motor Operated Valve Risk-Based Inspection Code Case New

2001E

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.
CODE CASE

NUMBER

TABLE 2, CONDITIONALLY ACCEPTABLE 

OM CODE CASES

EDITION/

ADDENDA

CONDITION

9

OMN-11,

Rev. 0

(continued)

Motor Operated Valve Risk-Based Inspection Code Case New

2001E

(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: Condition regarding allowable methodologies for MOV

risk ranking specified for the use of OMN-1 also applies to

OMN-11.]

OMN-12,

Rev. 0

Alternative Requirements for Inservice Testing Using Risk Insights

for Pneumatically- and Hydraulically-Operated Valve Assemblies

in Light-Water Reactor Power Plants

New

2001E

(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.
CODE CASE

NUMBER

TABLE 2, CONDITIONALLY ACCEPTABLE 

OM CODE CASES

EDITION/

ADDENDA

CONDITION

10

OMN-12,

Rev. 0

(continued)

Alternative Requirements for Inservice Testing Using Risk Insights

for Pneumatically- and Hydraulically-Operated Valve Assemblies

in Light-Water Reactor Power Plants

New

2001E

(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

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.
CODE CASE

NUMBER

TABLE 2, CONDITIONALLY ACCEPTABLE 

OM CODE CASES

EDITION/

ADDENDA

CONDITION

11

OMN-12,

Rev. 0

(continued)

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

New

2001E

(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 designbasis 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.]
12

Appendix A

Operation and Maintenance Code Cases Publication Information

CODE CASE

NUMBER

EDITION/ADDENDA DATE

OMN-1 1999 Addenda July 1, 1999

OMN-2 1998 Edition July 1, 1998

OMN-3 1998 Edition July 1, 1998

OMN-4 1999 Addenda July 1, 1999

OMN-5 1999 Addenda July 1, 1999

OMN-6 1999 Addenda July 1, 1999

OMN-7 2000 Addenda July 1, 2000

OMN-8 2000 Addenda July 1, 2000

OMN-9 2000 Addenda July 1, 2000

OMN-10 2000 Addenda July 1, 2000

OMN-11 2001 Edition July 1, 2001

OMN-12 2001 Edition July 1, 2001

OMN-13 2001 Edition July 1, 2001
1 Code Case is unacceptable for use; See Regulatory Guide 1.193.

13

Appendix B

Numerical Listing of Operation and Maintenance Code Cases

OMN-1

OMN-2

OMN-3

OMN-4

OMN-5

OMN-6

OMN-7

OMN-8

OMN-9

OMN-101

OMN-11

OMN-12

OMN-13
14

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,” that incorporates this regulatory guide by

reference.

A copy of the Regulatory Analysis is available for inspection and/or copying for a

fee at the NRC’s Public Document Room at 11555 Rockville Pike, Public File Area

(O-1F21), Rockville, MD. The PDR’s mailing address is USNRC PDR, Washington, DC

20555-0001; telephone (301)415-4737 or toll-free 1-(800)397-4209; fax (301)415-3548;

e-mail <PDR@NRC.GOV> . Electronic copies of the Regulatory Analysis are available

in NRC’s Public Electronic Reading Room, which can be accessed through the NRC’s

website, ML031490533.