NRC: Periodic Verification of Design-Basis Capability of Safety-Related Motor-Operated Valves (Generic Letter 96-05)

file:///X|/...20%20Periodic%20Verification%20of%20Design-Basis%20Capability%20of%20Safety-Related%20Motor-Operated%20Valves%20(Generic%20Letter%2096-05).html[3/3/2015 12:43:29 PM]

Home > NRC Library > Document Collections > Generic Communications > Generic Letters > 1996 > Gl96005

Periodic Verification of Design-Basis Capability of Safety-Related MotorOperated Valves (Generic Letter 96-05)

UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, DC 20555-0001

September 18, 1996

NRC GENERIC LETTER 96-

05:

PERIODIC VERIFICATION OF DESIGN-BASIS CAPABILITY OF SAFETY-RELATED MOTOR-OPERATED

VALVES

Addressees

All holders of operating licenses (except those licenses that have been amended to possession-only status) or construction permits for

nuclear power reactors.

Purpose

The U.S. Nuclear Regulatory Commission (NRC) is issuing this generic letter to (1) discuss the periodic verification of the capability of

safety-related motor-operated valves (MOVs) to perform their safety functions consistent with the current licensing bases of nuclear

power plants, (2) request that addressees implement actions described herein, and (3) require that addressees provide to the NRC a

written response to this generic letter relating to implementation of the requested actions.

Background

NRC regulations require that components that are important to the safe operation of a nuclear power plant, including MOVs, be treated

in a manner that provides assurance of their performance. Appendix A, "General Design Criteria for Nuclear Power Plants," and

Appendix B, "Quality Assurance Criteria for Nuclear Power Plants and Fuel Reprocessing Plants," to Part 50 of Title 10 of the Code of

Federal Regulations (10 CFR Part 50) include broad- based requirements in this regard. In 10 CFR 50.55a(f), the NRC requires licensees

to comply with Section XI of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code).

Nuclear power plant operating experience, valve performance problems and MOV research have revealed that the focus of the ASME

Code on stroke time and leak-rate testing for MOVs was not sufficient in light of the design of the valves and the conditions under

which they must function. For this reason, on June 28, 1989, the NRC staff issued Generic Letter (GL) 89-10, "Safety-Related MotorOperated Valve Testing and Surveillance." In GL 89-10, the staff requested that licensees and permit holders ensure the capability of

MOVs in safety-related systems to perform their intended functions by reviewing MOV design bases, verifying MOV switch settings

initially and periodically, testing MOVs under design-basis conditions where practicable, improving evaluations of MOV failures and

necessary corrective action, and trending MOV problems. The staff requested that licensees complete the GL 89-10 program within

approximately three refueling outages or 5 years from the issuance of the generic letter. Permit holders were requested to complete the

GL 89-10 program before plant startup or in accordance with the above schedule, whichever was later.

Recommendation "d" of GL 89-10 requested that licensees and permit holders prepare procedures to ensure that correct MOV switch

settings are maintained throughout the life of the plant. GL 89-10 stated that it may become necessary to adjust MOV switch settings

because of wear or aging and that additional measures beyond ASME Code stroke-time testing should be taken to adequately verify

that the switch settings ensure MOV operability. Recommendation "j" of GL 89-10 stated that licensees should periodically verify MOV

capability every 5 years or every 3 refueling outages. Recommendation "h" of GL 89-10 requested that licensees evaluate trends in

MOV performance every 2 years or at each refueling outage.

The staff issued seven supplements to GL 89-10 that provided additional guidance and information on GL 89-10 program scope,

design-basis reviews, switch settings, testing, periodic verification, trending, and schedule extensions. Supplement 6 to GL 89-10 stated

that no licensee had adequately justified the use of static test data as the sole basis for periodically ensuring MOV design-basis

capability.

GL 89-10 and its supplements provide only limited guidance regarding periodic verification and the measures appropriate to assure

preservation of design- basis capability. This generic letter provides more complete guidance regarding periodic verification of safetyrelated MOVs and supersedes GL 89-10 and its supplements with regard to MOV periodic verification. Although this guidance could have

HOME FAQ GLOSSARY FACILITY LOCATOR WHAT'S NEW SITE HELP INDEX A-Z CONTACT US BROWSE ALOUD EMAIL UPDATES

PRINT

NRC

LIBRARY

NUCLEAR

REACTORS

NUCLEAR

MATERIALS

RADIOACTIVE

WASTE

NUCLEAR

SECURITY

PUBLIC MEETINGS &

INVOLVEMENT

ABOUT

NRC
NRC: Periodic Verification of Design-Basis Capability of Safety-Related Motor-Operated Valves (Generic Letter 96-05)

file:///X|/...20%20Periodic%20Verification%20of%20Design-Basis%20Capability%20of%20Safety-Related%20Motor-Operated%20Valves%20(Generic%20Letter%2096-05).html[3/3/2015 12:43:29 PM]

been provided in a supplement to GL 89-10, the staff has prepared this new generic letter to allow closure of the staff review of GL 89-

10 programs as promptly as possible.

Discussion

Nuclear power plant utilities are nearing completion of the verification of the design-basis capability of their GL 89-10 MOVs. The NRC

staff has been closing its review of individual GL 89-10 programs on the basis of the completion of the design-basis verification of

safety-related MOVs at each nuclear power plant and the utility establishment of a program for periodic verification of MOV designbasis capability and for the trending of MOV problems. The staff may conduct a more complete review of licensee programs for MOV

periodic verification as part of the implementation of this generic letter.

The staff believes that various approaches can be taken by licensees to establish a periodic verification program that provides

confidence in the long-term capability of MOVs to perform their design-basis safety functions. With each approach, the licensee should

address potential degradation that can result in (1) the increase in thrust or torque requirements to operate the valves and (2) the

decrease in the output capability of the motor actuator. The staff has long recognized the limitations of using stroke-time testing as a

means of monitoring the operational readiness of MOVs (see GL 89-04, Supplement 1, "Guidance on Developing Acceptable Inservice

Testing Programs") and has supported industry efforts to improve MOV periodic monitoring under the inservice testing (IST) program

and GL 89-10. As such, the staff would consider a periodic verification program that provides an acceptable level of quality and safety

as an alternative to the current IST requirements for stroke-time testing and could authorize such an alternative, upon application by a

licensee, pursuant to the provisions of 10 CFR 50.55a(a)(3)(i). Guidance in this generic letter and GL 89-04 (Supplement 1) could be

used by a licensee in determining whether its periodic verification program provides an acceptable level of quality and safety.

The staff believes that various approaches can be taken by licensees to establish a periodic verification program that provides

confidence in the long-term capability of MOVs to perform their design-basis safety functions. With each approach, the licensee should

address potential degradation that can result in (1) the increase in thrust or torque requirements to operate the valves and (2) the

decrease in the output capability of the motor actuator. The staff has long recognized the limitations of using stroke-time testing as a

means of monitoring the operational readiness of MOVs (see GL 89-04, Supplement 1, "Guidance on Developing Acceptable Inservice

Testing Programs") and has supported industry efforts to improve MOV periodic monitoring under the inservice testing (IST) program

and GL 89-10. As such, the staff would consider a periodic verification program that provides an acceptable level of quality and safety

as an alternative to the current IST requirements for stroke-time testing and could authorize such an alternative, upon application by a

licensee, pursuant to the provisions of 10 CFR 50.55a(a)(3)(i). Guidance in this generic letter and GL 89-04 (Supplement 1) could be

used by a licensee in determining whether its periodic verification program provides an acceptable level of quality and safety.

The staff believes that various approaches can be taken by licensees to establish a periodic verification program that provides

confidence in the long-term capability of MOVs to perform their design-basis safety functions. With each approach, the licensee should

address potential degradation that can result in (1) the increase in thrust or torque requirements to operate the valves and (2) the

decrease in the output capability of the motor actuator. The staff has long recognized the limitations of using stroke-time testing as a

means of monitoring the operational readiness of MOVs (see GL 89-04, Supplement 1, "Guidance on Developing Acceptable Inservice

Testing Programs") and has supported industry efforts to improve MOV periodic monitoring under the inservice testing (IST) program

and GL 89-10. As such, the staff would consider a periodic verification program that provides an acceptable level of quality and safety

as an alternative to the current IST requirements for stroke-time testing and could authorize such an alternative, upon application by a

licensee, pursuant to the provisions of 10 CFR 50.55a(a)(3)(i). Guidance in this generic letter and GL 89-04 (Supplement 1) could be

used by a licensee in determining whether its periodic verification program provides an acceptable level of quality and safety.

In Attachment 1 to this generic letter, the staff discusses industry and regulatory activities and programs related to maintaining longterm capability of safety-related MOVs and provides the staff position regarding American Society of Mechanical Engineers (ASME) Code

Case OMN-1. The staff also identifies attributes of periodic verification programs that the staff considers to be effective and an example

approach in implementing those attributes. Additionally, as discussed in Attachment 1, certain licensees developed MOV periodic

verification programs that the staff found acceptable during the closure of its review of GL 89-10 programs.

Licensees may consolidate long-term MOV periodic verification and trending activities as part of their programs to meet the Maintenance

Rule (10 CFR 50.65) and other applicable regulations.

Requested Actions

Each addressee of this generic letter is requested to establish a program, or to ensure the effectiveness of its current program, to verify

on a periodic basis that safety-related MOVs continue to be capable of performing their safety functions within the current licensing

bases of the facility. The program should ensure that changes in required performance resulting from degradation (such as those

caused by age) can be properly identified and accounted for. Addressees that have developed periodic verification programs in response

to GL 89-10 should review those programs to determine whether any changes are appropriate in light of the information in this generic

letter.

Required Response

All addressees are required to submit the following written responses to this generic letter:

1. Within 60 days from the date of this generic letter, a written response indicating whether or not the addressee will implement

the action(s) requested herein. If the addressee intends to implement the requested action(s), the addressee shall submit a

schedule for completing implementation. If an addressee chooses not to implement the requested action(s), the addressee shall

submit a description of any proposed alternative course of action, the schedule for completing the alternative course of action (if

applicable), and the safety basis for determining the acceptability of the planned alternative course of action.

2. Within 180 days from the date of this generic letter, or upon notification to NRC of completion of GL 89-10 (whichever is later),

the addressee shall submit a written summary description of its MOV periodic verification program established in accordance with

the Requested Actions paragraph or the alternative course of action established by the addressee in response to item 1 above.

All addressees shall submit the required written reports to the U.S. Nuclear Regulatory Commission, ATTN: Document Control Desk,
NRC: Periodic Verification of Design-Basis Capability of Safety-Related Motor-Operated Valves (Generic Letter 96-05)

file:///X|/...20%20Periodic%20Verification%20of%20Design-Basis%20Capability%20of%20Safety-Related%20Motor-Operated%20Valves%20(Generic%20Letter%2096-05).html[3/3/2015 12:43:29 PM]

Washington, D.C. 20555- 0001, under oath or affirmation under the provisions of Section 182a, Atomic Energy Act of 1954, as

amended, and 10 CFR 50.54(f). In addition, a copy of the report shall be submitted to the appropriate Regional Administrator.

Backfit Discussion

10 CFR Part 50 (Appendix A, Criteria 1 and 4) and plant licensing safety analyses require and/or commit that the addressees design

and test components and systems to provide adequate assurance that those systems can perform their safety functions. Other

individual criteria in Appendix A to 10 CFR Part 50, or commitments made by licensees in their Final Safety Analysis Reports, apply to

specific systems. In accordance with those regulations and licensing commitments, and under the additional provisions of Criterion XVI

of Appendix B to 10 CFR Part 50, licensees are required to take actions to ensure that safety-related MOVs are capable of performing

their required safety functions.

Recommendation "d" of GL 89-10 requested that licensees and permit holders prepare procedures to ensure that correct MOV switch

settings are maintained throughout the life of the plant. GL 89-10 stated that it may become necessary to adjust MOV switch settings

because of wear or aging and that additional measures beyond ASME Code stroke-time testing should be taken to adequately verify

that the switch settings ensure MOV operability. The NRC staff issued GL 89-10 as a compliance backfit as defined in 10 CFR 50.109.

The actions requested in this generic letter are considered compliance backfits, under the provisions of 10 CFR 50.109 and existing NRC

procedures, to ensure that safety-related MOVs are capable of performing their intended safety functions. In accordance with the

provisions of 10 CFR 50.109 regarding compliance backfits, a full backfit analysis was not performed for this proposed action; but the

staff performed a documented evaluation, which stated the objectives of and reasons for the requested actions and the basis for

invoking the compliance exception. A copy of this evaluation will be made available in the NRC Public Document Room.

Federal Register Notification

This generic letter was issued for a 60-day public comment period on February 20, 1996.

Paperwork Reduction Act Statement

This generic letter contains information collections 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 Management and Budget, approval number 3150-0011, which expires July

31, 1997.

The public reporting burden for this collection of information is estimated to average 75 hours per response, including the time for

reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the

collection of information. The U.S. Nuclear Regulatory Commission is seeking public comment on the potential impact of the collection of

information contained in the generic letter and on the following issues:

1. Is the proposed collection of information necessary for the proper performance of the functions of the NRC, including whether the

information will have practical utility?

2. Is the estimate of burden accurate?

3. Is there a way to enhance the quality, utility, and clarity of the information to be collected?

4. How can the burden of the collection of information be minimized, including the use of automated collection techniques?

Send comments on any aspect of this collection of information, including suggestions for reducing this burden, to the Information and

Records Management Branch, T-6 F33, U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, and to the Desk Officer,

Office of Information and Regulatory Affairs, NEOB-10202 (3150-0011), Office of Management and Budget, Washington, DC 20503.

The NRC may not conduct or sponsor, and a person is not required to respond to, a collection of information unless it displays a

currently valid OMB control number.

If you have any questions about this matter, please contact the technical contact or the lead project manager listed below, or the

appropriate Office of Nuclear Reactor Regulation (NRR) project manager.

/s/

Thomas T. Martin, Director

Division of Reactor Program Management

Office of Nuclear Reactor Regulation

Technical contact: Thomas G. Scarbrough, NRR 

(301) 415-2794 

Email: tgs@nrc.gov

Lead Project Manager: Allen G. Hansen, NRR 

(301) 415-1390 

Email: agh@nrc.gov

Attachments:

1. Activities and Programs Related to Maintaining Long-Term Capability of Safety-Related Motor-Operated Valves

Attachment 1

ACTIVITIES AND PROGRAMS RELATED TO MAINTAINING LONG-TERM

CAPABILITY OF SAFETY-RELATED MOTOR-OPERATED VALVES
NRC: Periodic Verification of Design-Basis Capability of Safety-Related Motor-Operated Valves (Generic Letter 96-05)

file:///X|/...20%20Periodic%20Verification%20of%20Design-Basis%20Capability%20of%20Safety-Related%20Motor-Operated%20Valves%20(Generic%20Letter%2096-05).html[3/3/2015 12:43:29 PM]

Over the last several years, licensees and permit holders have conducted tests of a large number of MOVs under static and dynamic

conditions as part of the implementation of their GL 89-10 programs. From these tests, licensees and permit holders identified

significant weaknesses in the design and qualification of MOVs used in nuclear power plants. These weaknesses caused MOVs to fail to

operate properly during testing. Further, some MOVs operated adequately under test conditions, but analyses of the test results

subsequently revealed that the MOVs might not have performed their safety functions under design-basis conditions. Licensees and

permit holders are applying significant resources to ensure that, despite the potential weak- nesses in original design and qualification,

MOVs are currently capable of performing their safety functions under design-basis conditions.

In completing their GL 89-10 programs, licensees and permit holders may have based their confidence in the current design-basis

capability of some safety- related MOVs on the thrust/torque requirements obtained directly from the dynamic testing without additional

margin for age-related degradation. For some valves, licensees may have employed other methods (such as grouping) to establish

design-basis capability. In some cases, the thrust/torque requirements obtained from the dynamic tests were significantly less than the

thrust/torque required to operate apparently identical MOVs. Below, the staff discusses a research program conducted by the Electric

Power Research Institute (EPRI) that indicates the potential for the thrust/torque required to operate a valve to increase with service

until a plateau is reached. Aging can also decrease the thrust/torque output of motor actuators. Therefore, an effective program for

periodic verification of MOV design capability will require that licensees understand the performance of their safety-related MOVs and

the manner in which that performance can change with aging.

Static diagnostic tests provide information on the thrust/torque output of the motor actuator and any changes to the motor-actuator

output as a result of aging effects. The thrust and torque required to operate a valve are highly dependent on the differential pressure

and flow across the valve disk, which are not present during static testing. Therefore, dynamic tests can provide information on the

thrust/torque requirements and any changes to those requirements as a result of aging effects. Efforts are underway within the nuclear

industry to develop methods to obtain information from static tests that would allow prediction of valve dynamic performance. As

discussed below, EPRI has developed an analytical methodology that, when combined with static test data, provides bounding

information on the thrust/torque requirements to operate gate, globe and butterfly valves under dynamic conditions.

While there may be benefits to performing dynamic testing to ascertain the thrust/torque requirements and changes to these

requirements as a result of aging, there are also potential detriments to dynamic testing (e.g., blowdown testing by EPRI resulted in

damage to some valves). The staff has not concluded that dynamic testing is the preferred method of periodic verification testing and

believes dynamic testing may not be appropriate for certain situations. The proposed method for periodic verification testing and

demonstration of a particular valve's acceptability and ability to perform consistent with its design basis are the responsibility of the

licensee. The proposed method for MOV periodic verification testing may be dependent on the valve and its application as well as the

valve's performance history and its contribution to overall plant risk.

Electric Power Research Institute (EPRI)

A motor-operated valve (MOV) testing program conducted by EPRI has provided significant information regarding the long-term designbasis capability of safety-related MOVs. In addition to finding that the thrust required to operate gate valves is typically greater than

the thrust originally predicted by valve vendors, the EPRI program found that the thrust required to operate gate valves can increase

with valve strokes until a plateau is reached. EPRI also found that certain valves could be damaged during high flow and blowdown

testing.

The Nuclear Energy Institute (NEI) submitted EPRI Topical Report TR-103237, "EPRI MOV Performance Prediction Program," describing

the methodology developed by EPRI to predict dynamic thrust and torque requirements for gate, globe, and butterfly valves without

dynamic tests by licensees. The staff prepared a safety evaluation (SE), dated March 15, 1996, which approves the topical report for

use and reference. Hence, the staff would find it acceptable if a licensee applied the EPRI methodology (in accordance with this generic

letter and the conditions or limitations contained in the NRC staff's safety evaluation (SE) in establishing a program for periodic

verification of MOV design-basis capability.

Boiling Water Reactor (BWR) Owners' Group

The BWR Owners' Group submitted Topical Report NEDC 32264, "Application of Probabilistic Safety Assessment to Generic Letter 89-10

Implementation," which provides a methodology to rank the MOVs in GL 89-10 programs with respect to their relative importance to

core damage frequency, including appropriate considerations regarding other consequences to be added by an expert panel. The staff

prepared an SE, dated February 27, 1996, on the topical report. The staff considers the methodology acceptable (in accordance with

any conditions or limitations contained in the NRC staff's SE) for ranking MOVs in BWRs because the plant-specific IPE-based insights

are supplemented by generic insights and expert review involving additional considerations, such as external events and shutdown

issues. In addition, the use of the MOV rankings is in combination with deterministic considerations that ensure a minimally acceptable

frequency of testing is established even for the least risk- significant valves.

NRC Research Activities

In the 1980s, the NRC Office of Nuclear Regulatory Research (RES) sponsored a test program by the Idaho National Engineering

Laboratory (INEL) to determine the thrust required to operate motor-operated gate valves under dynamic flow conditions. The results

of the EPRI valve test program confirmed the findings of the NRC's smaller-scale test program. More recently, preliminary results from

the testing of valve material samples sponsored by RES indicate that valve friction can increase with aging.

With respect to MOV ranking, RES sponsored a study of appropriate frequencies of periodic testing of MOVs based on their risk

significance. This work is summarized in an article titled "Risk-Based Approach for Prioritizing Motor- Operated Valves" in NUREG/CP0137, "Proceedings of the Third NRC/ASME Symposium on Valve and Pump Testing."

American Society of Mechanical Engineers (ASME)

Licensees are currently bound by the requirements in their Code-of-record regarding stroke-time inservice testing (IST), as modified by

relief requests approved by the staff. Licensees have also verified MOV design-basis capability pursuant to their GL 89-10

commitments.
NRC: Periodic Verification of Design-Basis Capability of Safety-Related Motor-Operated Valves (Generic Letter 96-05)

file:///X|/...20%20Periodic%20Verification%20of%20Design-Basis%20Capability%20of%20Safety-Related%20Motor-Operated%20Valves%20(Generic%20Letter%2096-05).html[3/3/2015 12:43:29 PM]

The ASME Operations and Maintenance Code Committee has developed a method to verify MOV design-basis capability through periodic

testing. Through a non- mandatory code case (OMN-1, entitled: "Alternative Rules for Preservice and Inservice Testing of Certain

Electric Motor Operated Valve Assemblies in LWR Power Plants, OM Code 1995 Edition; Subsection ISTC"), ASME is allowing the

replacement of frequent stroke-time testing with periodic exercising of all safety-related MOVs once per cycle and diagnostic testing

under static or dynamic conditions, as appropriate.

With certain limitations, the staff considers the method described in the code case to meet the intent of this generic letter:

(1) When implementing the code case, the staff notes as an additional precaution that the benefits (such as identification of

decreased thrust output and increased thrust requirements) and potential adverse effects (such as accelerated aging or valve

damage) need to be considered when determining appropriate testing for each MOV.

(1) When implementing the code case, the staff notes as an additional precaution that the benefits (such as identification of

decreased thrust output and increased thrust requirements) and potential adverse effects (such as accelerated aging or valve

damage) need to be considered when determining appropriate testing for each MOV.

(2) The code case states that the maximum inservice test frequency shall not exceed 10 years. The staff agrees with this

condition of a maximum test interval of 10 years based on current knowledge and experience. In addition to this maximum

test interval, where a selected test interval extends beyond five years or three refueling outages (whichever is longer), the

licensee should evaluate information obtained from valve testing conducted during the first five-year or three-refuelingoutage time period to validate assumptions made in justifying the longer test interval. Based on performance and test

experience obtained during the initial interval, a licensee may be able to justify lengthened MOV periodic verification intervals.

(3) Some licensees are developing programs for inservice testing that include consideration of risk insights. As part of an industry

pilot effort, two licensees have submitted requests to utilize this approach to determine inservice test frequencies for certain

components, in lieu of testing these components per the frequencies specified by the ASME Code. Licensees involved in these

IST programs that seek to implement the ASME code case need to specifically address the relationship of the code case to

their pilot initiative.

Plant-Specific Programs

The staff has found effective programs for periodic verification of safety- related MOV design-basis capability at nuclear power plants to

be characterized by several attributes, as follow:

Risk insights to supplement the deterministic considerations may be used to prioritize valve test activities, such as frequency of

individual valve tests and selection of valves to be tested.

The valve test program should provide adequate confidence that safety- related MOVs will remain operable until the next

scheduled test.

The importance of the valve should be considered in determining an appropriate mix of exercising and diagnostic testing. In

establishing the mix of testing, the licensee should consider the benefits (such as identification of decreased thrust output and

increased thrust requirements) and potential adverse effects (such as accelerated aging or valve damage) when determining the

appropriate type of periodic verification testing for each safety-related MOV.

All safety-related MOVs covered by the GL 89-10 program should be considered in the development of the periodic verification

program. The program should include safety-related MOVs that are assumed to be capable of returning to their safety position

when placed in a position that prevents their safety system (or train) from performing its safety function; and the system (or

train) is not declared inoperable when the MOVs are in their nonsafety position.

Licensees should evaluate and monitor valve performance and maintenance and periodically adjust the periodic verification

program, as appropriate.

Licensees of several facilities (for example, Callaway, Monticello, and South Texas) had established MOV periodic verification programs

that the staff found acceptable during closure of its review of GL 89-10 programs. One approach to MOV periodic verification that the

staff found acceptable is to diagnostically test each safety-related MOV every 5 years (or every 3 refueling outages) to determine thrust

and torque motor-actuator output and any changes in the output. A specific margin to account for potential degradation such as that

caused by age (in addition to margin for diagnostic error, equipment repeatability, load-sensitive behavior, and lubricant degradation) is

established above the minimum thrust and torque requirements determined under the GL 89-10 program. The selection of MOVs for

testing and their test conditions should take into account safety significance, available margin, MOV environment, and the benefits and

potential adverse effects of static and dynamic periodic verification testing on the selected MOV sample. Measures such as grouping and

sharing of valve performance between facilities are appropriate to minimize the need to conduct more rigorous periodic verification

tests.

As discussed in this generic letter, the staff has long recognized the limitations of using stroke-time testing as a means of monitoring

the operational readiness of MOVs (see GL 89-04) and has supported industry efforts to improve MOV periodic monitoring under the IST

program and GL 89-10. As such, the staff would consider a periodic verification program that provides an acceptable level of quality

and safety as an alternative to the current IST requirements for stroke-time testing and could authorize such an alternative, upon

application by a licensee, pursuant to the provisions of 10 CFR 50.55a(a)(3)(i).

Page Last Reviewed/Updated Friday, June 28, 2013

HOME

NEWS RELEASES

ABOUT US

STRATEGIC PLAN

POPULAR DOCUMENTS

INFO DIGEST

STAY CONNECTED
NRC: Periodic Verification of Design-Basis Capability of Safety-Related Motor-Operated Valves (Generic Letter 96-05)

file:///X|/...20%20Periodic%20Verification%20of%20Design-Basis%20Capability%20of%20Safety-Related%20Motor-Operated%20Valves%20(Generic%20Letter%2096-05).html[3/3/2015 12:43:29 PM]

EVENT REPORTS

ADAMS

OPEN GOV

DIGITAL GOVERNMENT

STUDENTS & TEACHERS

PHOTOS & VIDEO

FOR DEVELOPERS

BUDGET & PERFORMANCE

PERF & ACCOUNTABILITY REPT

HISTORY OF THE NRC

CAREER OPPORTUNITIES

NRC ETHICS

AGENCY STATUS

CONTACT US

FACTSHEETS & BROCHURES

FORMS

ELECTRONIC SUBMITTALS APPLICATION

NRC REPORTS – NUREG

NRC REGULATIONS – 10-CFR

INSPECTION REPORTS

PLAIN WRITING

ENFORCEMENT ACTIONS

RULEMAKING

BLOG

FACEBOOK

TWITTER

YOUTUBE

FLICKR

GOVDELIVERY

RSS

Regulations.gov USA.gov Recovery FOIA No Fear EEO Inspector General Program Site Map Accessibility Privacy Policy Site Disclaimer For Employees