NRC Generic Letter 1996-05: Difference between revisions

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{{#Wiki_filter:UNITED STATES NUCLEAR REGULATORY  
{{#Wiki_filter:UNITED STATES
COMMISSION
                        NUCLEAR REGULATORY COMMISSION
OFFICE OF NUCLEAR REACTOR REGULATION
                    OFFICE OF NUCLEAR REACTOR REGULATION
WASHINGTON, D.C. 20555-0001 September  
                          WASHINGTON, D.C. 20555-0001 September 18, 1996 NRC GENERIC LETTER 96-05:   PERIODIC VERIFICATION OF DESIGN-BASIS CAPABILITY
18, 1996 NRC GENERIC LETTER 96-05: PERIODIC VERIFICATION  
                            OF SAFETY-RELATED MOTOR-OPERATED VALVES
OF DESIGN-BASIS  
CAPABILITY
OF SAFETY-RELATED  
MOTOR-OPERATED  
VALVES  


==Addressees==
==Addressees==
Line 29: Line 24:


==Purpose==
==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.
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.


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  
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).
(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.
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 Motor-Operated 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
9609100488      PDf AocK            500000 3 urAP            5 4 I /Alt


For this reason, on June 28, 1989, the NRC staff issued Generic Letter (GL) 89-10. "Safety-Related Motor-Operated 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.
GL 96-05 September 18. 1996 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.


The staff requested that licensees complete the GL 89-10 program within approximately three refueling outages or 5 years from the issuance of 9609100488 PDf AocK 500000 3 urAP I /Alt 5 4 GL 96-05 September
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.
18. 1996 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.
Recommendation "j"of GL 89-10 stated that licensees should periodically verify MOV capability every 5 years or every 3 refueling outages.


Supplement
Recommendation "h"of GL 89-10 requested that licensees evaluate trends in MOV
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.
performance every 2 years or at each refueling outage.


GL 89-10 and its supplements provide only limited guidance regarding periodic verification and the measures appropriate to assure preservation of design-basis capability.
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.


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


Although this guidance could have 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 design-basis capability and for the trending of MOV problems.
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 design-basis 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 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.
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.
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.


GL 96-05 September  
GL 96-05 September 18, 1996 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")
18, 1996 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  
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.
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 long-term 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  
In Attachment 1 to this generic letter, the staff discusses industry and regulatory activities and programs related to maintaining long-term 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.
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.
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.


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.
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==
==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.
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.


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 GL 96-05 September
Required Response All addressees are required to submit the following written responses to this generic letter:
18, 1996 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, 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).
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)
In addition, a copy of the report shall be submitted to the appropriate Regional Administrator.
      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


==Backfit Discussion==
GL 96-05 September 18, 1996 alternative course of action (if applicable), and the safety basis for determining the acceptability of the planned alternative course of action.
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.
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.


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.
All addressees shall submit the required written reports to the U.S. Nuclear Regulatory Commission, ATTN: Document Control Desk, 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.


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.
==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.


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.
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.


A copy of this evaluation will be made available in the NRC Public Document Room.
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==
==Federal Register Notification==
This generic letter was issued for a 60-day public comment period on February 20, 1996.
This generic letter was issued for a 60-day public comment period on February 20, 1996.


GL 96-05 September  
GL 96-05 September 18, 1996  
18, 1996  


==Paperwork Reduction Act Statement==
==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.
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 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.


Attachment
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 GL 96-XX GL 96-05 September
      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?
18, 1996 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.[Original signed by]Thomas T. Martin, Director Division of Reactor Program Management Office of Nuclear Reactor Regulation Technical contact: TM El Lead Project Manager: homas G. Scarbrough, NRR 301) 415-2794 mail: tgs@nrc.gov Allen G. Hansen, NRR (301) 415-1390 Email: agh@nrc.gov Attachments:
      2. Is the estimate of burden accurate?
1. Activities and Programs Related to Maintaining Long-Term Capability of Safety-Related Motor-Operated Valves 2. List of Recently Issued NRC Generic Letters Tech Editor reviewed and concurred on 08/01/95 DOCUMENT NAME: 96-05.GL *SEE PREVIOUS CONCURRENCES
      3. Is there a way to enhance the quality, utility, and clarity of the information to be collected?
To receive a copy of this document.
      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.


Indicate in the box: C' -Copy w/o attachment/enclosure
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
'E' -Copy wlattachmentlenclosure
control number.
'N' -No copy OFFICE TECH CONT l OGC H C\PECB D\qtM L_NAME TGScarbro SChidakel*
0AC5/26/96
0 i-I.DATE 05/17/96 06/10/96 05/26/96 09likY96I OFFICIAL RECORD COPY
Attachment
1 GL 96-05 September
18, 1996 ACTIVITIES
AND PROGRAMS RELATED TO MAINTAINING
LONG-TERM
CAPABILITY
OF SAFETY-RELATED
MOTOR-OPERATED
VALVES 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 qualifica- tion 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 sub-sequently revealed that the MOVs might not have performed their safety functions under design-basis conditions.
Attachment 1 GL 96-XX GL 96-05 September 18, 1996 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.


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.
[Original signed by]
                                                                      Thomas T. Martin, Director Division of Reactor Program Management Office of Nuclear Reactor Regulation Technical contact:                  TMhomas G. Scarbrough, NRR
                                                    301) 415-2794 Elmail: 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
              2. List of Recently Issued NRC Generic Letters Tech Editor reviewed and concurred on 08/01/95 DOCUMENT NAME:              96-05.GL                    *SEE PREVIOUS CONCURRENCES
To receive a copy of this document. Indicate inthe box: C' - Copy w/o attachment/enclosure 'E' - Copy wlattachmentlenclosure 'N' - No copy OFFICE        TECH CONT                  l OGC                    H C\PECB                D\qtM                    L_
  NAME          TGScarbro                        SChidakel*          0AC5/26/96            0 i-I
.DATE          05/17/96                          06/10/96            05/26/96              09likY96I
                                                OFFICIAL RECORD COPY


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.
Attachment 1 GL 96-05 September 18, 1996 ACTIVITIES AND PROGRAMS RELATED TO MAINTAINING
          LONG-TERM CAPABILITY OF SAFETY-RELATED MOTOR-OPERATED VALVES
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 qualifica- tion 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 sub- sequently 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.


For some valves, licensees may have employed other methods (such as grouping)  
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.
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.
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.


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.
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


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.
Attachment 1 GL 96-05 September 18, 1996 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.


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 Attachment
Electric Power Research Institute (EPRI)
1 GL 96-05 September
A motor-operated valve (MOV) testing program conducted by EPRI has provided significant information regarding the long-term design-basis capabi ity 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
18, 1996 concluded that dynamic testing is the preferred method of periodic verification testing and believes dynamic testing may not be appropriate for certain situations.
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 (inaccordance with this generic letter and the conditions or limitations contained in the NRC staff's
    'Inaddition to information applicable to MOV periodic verification, the EPRI program has revealed performance characteristics of MOVs that might adversely affect a licensee's determination of the current capability of certain MOVs. In particular, EPRI found that a high percentage of gate valves were damaged during hot water and steam blowdown testing with thrust requirements unable to be predicted. For MOVs that might be damaged under such conditions, EPRI esta lished possible modifications to valve internals for proper clearances and for rounding sharp edges. With respect to globe valves, EPRI found that reliable prediction of globe valve thrust requirements requires an appropriate seat or guide area in thrust calculations. Although EPRI tested only one globe valve under high temperature and blowdown conditions, the test revealed significantly higher thrust requirements than predicted. EPRI also found that load-sensitive behavior (or rate of loading)
can reduce actuator thrust output under dynamic conditions. EPRI has furnished the results of their MOV tests to licensees through industry meetings, and the NRC staff has disseminated the results of the tests to licensees through information notices on the EPRI test program and public meetings. Some licensees have already incorporated this information into their MOV programs.


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.
'p Attachment 1 GL 96-05 September 18, 1996 safety evaluation (SE) in establishing a program for periodic verification of MOV design-basis capability.


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 design-basis capabi ity 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.
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 a safety evaluation (SE), dated March 15, 1996, which approves the topical report for use and reference.
The staff prepared an SE, dated February 27, 1996. on the topical report. The staff considers the methodology acceptable (inaccordance 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.


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'In addition to information applicable to MOV periodic verification, the EPRI program has revealed performance characteristics of MOVs that might adversely affect a licensee's determination of the current capability of certain MOVs. In particular, EPRI found that a high percentage of gate valves were damaged during hot water and steam blowdown testing with thrust requirements unable to be predicted.
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.


For MOVs that might be damaged under such conditions, EPRI esta lished possible modifications to valve internals for proper clearances and for rounding sharp edges. With respect to globe valves, EPRI found that reliable prediction of globe valve thrust requirements requires an appropriate seat or guide area in thrust calculations.
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/CP-0137, "Proceedings of the Third NRC/ASME
Symposium on Valve and Pump Testing."
American Society of Mechanical EnQineers (ASME)
Licensees are currently bound by the requirements in their Code-of-record regarding stroke-time inservice testing (1ST), as modified by relief requests approved by the staff. Licensees have also verified MOV design-basis capability pursuant to their GL 89-10 commitments.


Although EPRI tested only one globe valve under high temperature and blowdown conditions, the test revealed significantly higher thrust requirements than predicted.
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


EPRI also found that load-sensitive behavior (or rate of loading)can reduce actuator thrust output under dynamic conditions.
Attachment 1 GL 96-05 September 18. 1996 safety-related MOVs once per cycle and diagnostic testing under static or dynamic conditions, as appropriate.


EPRI has furnished the results of their MOV tests to licensees through industry meetings, and the NRC staff has disseminated the results of the tests to licensees through information notices on the EPRI test program and public meetings.
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.


Some licensees have already incorporated this information into their MOV programs.
(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-refueling-outage 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.


'p Attachment
(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
1 GL 96-05 September
      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.
18, 1996 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.
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 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.
*    The valve test program should provide adequate confidence that safety- related MOVs will remain operable until the next scheduled test.


This work is summarized in an article titled "Risk-Based Approach for Prioritizing Motor-Operated Valves" in NUREG/CP-0137, "Proceedings of the Third NRC/ASME Symposium on Valve and Pump Testing." American Society of Mechanical EnQineers (ASME)Licensees are currently bound by the requirements in their Code-of-record regarding stroke-time inservice testing (1ST), as modified by relief requests approved by the staff. Licensees have also verified MOV design-basis capability pursuant to their GL 89-10 commitments.
*    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


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 Attachment  
Attachment 1 GL 96-05 September 18. 1996 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.
1 GL 96-05 September  
18. 1996 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)  
*    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.
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-refueling-outage time period to validate assumptions made in justifying the longer test interval.
*    Licensees should evaluate and monitor valve performance and maintenance and periodically adjust the periodic verification program, as appropriate.


Based on performance and test experience obtained during the initial interval, a licensee may be able to justify lengthened MOV periodic verification intervals.
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 (inaddition 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.


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


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 Attachment
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
1 GL 96-05 September
10 CFR 50.55a(a)(3)(i).
18. 1996 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.
Attachment 2 GL 96-05 September 18, 1996 LIST OF RECENTLY ISSUED GENERIC LETTERS
Generic                                            Date of ILLL-1I
  n+ttvr      riihiprt                            Issuance      Issued To
96-04          BORAFLEX DEGRADATION IN            06/26/96      ALL HOLDERS OF OLs SPENT FUEL POOL STORAGE                          FOR NPRs RACKS
95-09.          MONITORING AND TRAINING OF        04/05/96      ALL U.S. NUCLEAR
SUPP. 1        SHIPPERS AND CARRIERS OF                        REGULATORY COMMISSION
                RADIOACTIVE MATERIALS                            LICENSEES
96-03          RELOCATION OF THE PRESSURE        01/31/96      ALL HOLDERS OF OLs TEMPERATURE LIMIT CURVES                        OR CPs FOR NPRs AND LOW TEMPERATURE OVER-
                PRESSURE PROTECTION SYSTEM
                LIMITS
96-02          RECONSIDERATION OF NUCLEAR        01/31/96      ALL HOLDERS OF OLs POWER PLANT SECURITY                            OR CPs FOR NPRs REQUIREMENTS ASSOCIATED
                WITH AN INTERNAL THREAT
89-10.          CONSIDERATION OF VALVE            01/24/96      ALL HOLDERS OF OLs Supp. 7        MISPOSITIONING IN                                (EXCEPT THOSE LICENSES
                PRESSURIZED-WATER                                THAT HAVE BEEN AMENDED
                REACTORS                                        TO A POSSESSION ONLY
                                                                  STATUS) OR CPs FOR NPRs
96-01          TESTING OF SAFETY-RELATED          01/10/96    ALL HOLDERS OF OLs OR
                LOGIC CIRCUITS                                  CPs FOR NPRs
95-10          RELOCATION OF SELECTED              12/15/95    ALL HOLDERS OF OLs OR
                TECHNICAL SPECIFICATIONS                        CPs FOR NPRs REQUIREMENTS RELATED TO
                INSTRUMENTATION
95-09          MONITORING AND TRAINING OF          11/03/95    ALL U.S. NRC LICENSEES
                SHIPPERS AND CARRIERS OF
                RADIOACTIVE MATERIALS
95-08          10 CFR 50.54(p) PROCESS FOR        10/31/95    ALL HOLDERS OF OLs &
                CHANGES TO SECURITY PLANS                        CPs FOR NPRs WITHOUT PRIOR NRC APPROVAL
OL = OPERATING LICENSE
CP = CONSTRUCTION PERMIT
NPR = NUCLEAR POWER REACTORS


and South Texas) had established MOV periodic verification programs that the staff found acceptable during closure of its review of GL 89-10 programs.
Attachment 1 GL 96-XX GL 96-05 September 18, 1996 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.


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)
[Origina signed by]
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).
                                                                        Thomas T. Martin, Director Division of Reactor Program Management Office of Nuclear Reactor Regulation Technical contact:                 Thomas G. Scarbrough, NRR
Attachment
                                                  (,301) 415-2794 Email: tgs@nrc.gov Lead Project Manager:                    Allen G. Hansen, NRR
2 GL 96-05 September
                                                        (301) 415-1390
18, 1996 LIST OF RECENTLY ISSUED GENERIC LETTERS Generic I n+ttvr Date of Issuance riihiprt Issued To 96-04 95-09.SUPP. 1 96-03 96-02 89-10.Supp. 7 96-01 95-10 95-09 95-08 BORAFLEX DEGRADATION
                                                        Email: agh@nrc.gov Attachments:
IN SPENT FUEL POOL STORAGE RACKS MONITORING
              1. Activities and Programs Related to Maintaining Long-Term Capability of Safety-Related Motor-Operated Valves
AND TRAINING OF SHIPPERS AND CARRIERS OF RADIOACTIVE
              2. List of Recently Issued NRC Generic Letters fi tf C   "tff    p4V       (" ,r,(/
MATERIALS RELOCATION
              Tech Editor reviewed and concurred on 08/01/95 DOCUMENT NAME:               96-05.GL                   *SEE PREVIOUS CONCURRENCES
OF THE PRESSURE TEMPERATURE
To receive a copy of this document, hIdicate hIthe box: 'C' = Copy w/o attachment/enclosure 'E- - Copy w/attachmentlenclosure 'N' - No copy OFFICE         TECH CONT                     I OGC                   I 1C\PECB         [ D\fPMl NAME           TGScarbrough*                     SChidakel*           IAChaffee*           TT1aftFin DATE           05/17/96                         06/10/96               05/26/96             09/i&196 OFFICIAL RECORD COP
LIMIT CURVES AND LOW TEMPERATURE
                                                                                                                    71137
OVER-PRESSURE PROTECTION
                                                                                                                        1I-)}}
SYSTEM LIMITS RECONSIDERATION
OF NUCLEAR POWER PLANT SECURITY REQUIREMENTS
ASSOCIATED
WITH AN INTERNAL THREAT CONSIDERATION
OF VALVE MISPOSITIONING
IN PRESSURIZED-WATER
REACTORS TESTING OF SAFETY-RELATED
LOGIC CIRCUITS RELOCATION
OF SELECTED TECHNICAL
SPECIFICATIONS
REQUIREMENTS
RELATED TO INSTRUMENTATION
MONITORING
AND TRAINING OF SHIPPERS AND CARRIERS OF RADIOACTIVE
MATERIALS 10 CFR 50.54(p) PROCESS FOR CHANGES TO SECURITY PLANS WITHOUT PRIOR NRC APPROVAL 06/26/96 04/05/96 01/31/96 01/31/96 01/24/96 01/10/96 12/15/95 11/03/95 10/31/95 ALL HOLDERS OF OLs FOR NPRs ALL U.S. NUCLEAR REGULATORY
COMMISSION
LICENSEES ALL HOLDERS OF OLs OR CPs FOR NPRs ALL HOLDERS OF OLs OR CPs FOR NPRs ALL HOLDERS OF OLs (EXCEPT THOSE LICENSES THAT HAVE BEEN AMENDED TO A POSSESSION
ONLY STATUS) OR CPs FOR NPRs ALL HOLDERS OF OLs OR CPs FOR NPRs ALL HOLDERS OF OLs OR CPs FOR NPRs ALL U.S. NRC LICENSEES ALL HOLDERS OF OLs &CPs FOR NPRs OL = OPERATING
LICENSE CP = CONSTRUCTION
PERMIT NPR = NUCLEAR POWER REACTORS
Attachment
1 GL 96-XX GL 96-05 September
18, 1996 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.[Origina signed by]Thomas T. Martin, Director Division of Reactor Program Management Office of Nuclear Reactor Regulation Technical contact: T (, E Lead Project Manager: homas G. Scarbrough, NRR 301) 415-2794 mail: tgs@nrc.gov 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 2. List of Recently Issued NRC Generic Letters C i f tf "tf f p4V (" , r, (/Tech Editor reviewed and concurred on 08/01/95 DOCUMENT NAME: 96-05.GL *SEE PREVIOUS CONCURRENCES
To receive a copy of this document, hIdicate hI the box: 'C' = Copy w/o attachment/enclosure  
'E- -Copy w/attachmentlenclosure  
'N' -No copy OFFICE TECH CONT I OGC I 1C\PECB [ D\fPM l NAME TGScarbrough*  
SChidakel*  
IAChaffee*  
TT1aftFin DATE 05/17/96 06/10/96 05/26/96 09/i&196 OFFICIAL RECORD COP 71137 1I-)}}


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Revision as of 03:06, 24 November 2019

NRC Generic Letter 1996-005: Periodic Verification of Design-Basis Capability of Safety-Related Motor-Operated Valves
ML031110010
Person / Time
Site: Beaver Valley, Millstone, Hatch, Monticello, Calvert Cliffs, Dresden, Davis Besse, Peach Bottom, Browns Ferry, Salem, Oconee, Mcguire, Nine Mile Point, Palisades, Palo Verde, Perry, Indian Point, Fermi, Kewaunee, Catawba, Harris, Wolf Creek, Saint Lucie, Point Beach, Oyster Creek, Watts Bar, Hope Creek, Grand Gulf, Cooper, Sequoyah, Byron, Pilgrim, Arkansas Nuclear, Three Mile Island, Braidwood, Susquehanna, Summer, Prairie Island, Columbia, Seabrook, Brunswick, Surry, Limerick, North Anna, Turkey Point, River Bend, Vermont Yankee, Crystal River, Haddam Neck, Ginna, Diablo Canyon, Callaway, Vogtle, Waterford, Duane Arnold, Farley, Robinson, Clinton, South Texas, San Onofre, Cook, Comanche Peak, Yankee Rowe, Maine Yankee, Quad Cities, Humboldt Bay, La Crosse, Big Rock Point, Rancho Seco, Zion, Midland, Bellefonte, Fort Calhoun, FitzPatrick, McGuire, LaSalle, Fort Saint Vrain, Washington Public Power Supply System, Shoreham, Satsop, Trojan, Atlantic Nuclear Power Plant, Clinch River  Entergy icon.png
Issue date: 09/18/1996
From: Martin T
Office of Nuclear Reactor Regulation
To:
References
GL-96-005, NUDOCS 9609100488
Download: ML031110010 (13)


UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C. 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 Motor-Operated 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

9609100488 PDf AocK 500000 3 urAP 5 4 I /Alt

GL 96-05 September 18. 1996 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 safety-related MOVs and supersedes GL 89-10

and its supplements with regard to MOV periodic verification. Although this guidance could have 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 design-basis 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.

GL 96-05 September 18, 1996 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 long-term 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

GL 96-05 September 18, 1996 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, 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.

GL 96-05 September 18, 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 hours8.680556e-4 days <br />0.0208 hours <br />1.240079e-4 weeks <br />2.85375e-5 months <br /> 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.

Attachment 1 GL 96-XX GL 96-05 September 18, 1996 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.

[Original signed by]

Thomas T. Martin, Director Division of Reactor Program Management Office of Nuclear Reactor Regulation Technical contact: TMhomas G. Scarbrough, NRR

301) 415-2794 Elmail: 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

2. List of Recently Issued NRC Generic Letters Tech Editor reviewed and concurred on 08/01/95 DOCUMENT NAME: 96-05.GL *SEE PREVIOUS CONCURRENCES

To receive a copy of this document. Indicate inthe box: C' - Copy w/o attachment/enclosure 'E' - Copy wlattachmentlenclosure 'N' - No copy OFFICE TECH CONT l OGC H C\PECB D\qtM L_

NAME TGScarbro SChidakel* 0AC5/26/96 0 i-I

.DATE 05/17/96 06/10/96 05/26/96 09likY96I

OFFICIAL RECORD COPY

Attachment 1 GL 96-05 September 18, 1996 ACTIVITIES AND PROGRAMS RELATED TO MAINTAINING

LONG-TERM CAPABILITY OF SAFETY-RELATED MOTOR-OPERATED VALVES

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 qualifica- tion 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 sub- sequently 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

Attachment 1 GL 96-05 September 18, 1996 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 design-basis capabi ity 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 (inaccordance with this generic letter and the conditions or limitations contained in the NRC staff's

'Inaddition to information applicable to MOV periodic verification, the EPRI program has revealed performance characteristics of MOVs that might adversely affect a licensee's determination of the current capability of certain MOVs. In particular, EPRI found that a high percentage of gate valves were damaged during hot water and steam blowdown testing with thrust requirements unable to be predicted. For MOVs that might be damaged under such conditions, EPRI esta lished possible modifications to valve internals for proper clearances and for rounding sharp edges. With respect to globe valves, EPRI found that reliable prediction of globe valve thrust requirements requires an appropriate seat or guide area in thrust calculations. Although EPRI tested only one globe valve under high temperature and blowdown conditions, the test revealed significantly higher thrust requirements than predicted. EPRI also found that load-sensitive behavior (or rate of loading)

can reduce actuator thrust output under dynamic conditions. EPRI has furnished the results of their MOV tests to licensees through industry meetings, and the NRC staff has disseminated the results of the tests to licensees through information notices on the EPRI test program and public meetings. Some licensees have already incorporated this information into their MOV programs.

'p Attachment 1 GL 96-05 September 18, 1996 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 (inaccordance 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/CP-0137, "Proceedings of the Third NRC/ASME

Symposium on Valve and Pump Testing."

American Society of Mechanical EnQineers (ASME)

Licensees are currently bound by the requirements in their Code-of-record regarding stroke-time inservice testing (1ST), as modified by relief requests approved by the staff. Licensees have also verified MOV design-basis capability pursuant to their GL 89-10 commitments.

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

Attachment 1 GL 96-05 September 18. 1996 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.

(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-refueling-outage 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

Attachment 1 GL 96-05 September 18. 1996 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 (inaddition 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).

Attachment 2 GL 96-05 September 18, 1996 LIST OF RECENTLY ISSUED GENERIC LETTERS

Generic Date of ILLL-1I

n+ttvr riihiprt Issuance Issued To

96-04 BORAFLEX DEGRADATION IN 06/26/96 ALL HOLDERS OF OLs SPENT FUEL POOL STORAGE FOR NPRs RACKS

95-09. MONITORING AND TRAINING OF 04/05/96 ALL U.S. NUCLEAR

SUPP. 1 SHIPPERS AND CARRIERS OF REGULATORY COMMISSION

RADIOACTIVE MATERIALS LICENSEES

96-03 RELOCATION OF THE PRESSURE 01/31/96 ALL HOLDERS OF OLs TEMPERATURE LIMIT CURVES OR CPs FOR NPRs AND LOW TEMPERATURE OVER-

PRESSURE PROTECTION SYSTEM

LIMITS

96-02 RECONSIDERATION OF NUCLEAR 01/31/96 ALL HOLDERS OF OLs POWER PLANT SECURITY OR CPs FOR NPRs REQUIREMENTS ASSOCIATED

WITH AN INTERNAL THREAT

89-10. CONSIDERATION OF VALVE 01/24/96 ALL HOLDERS OF OLs Supp. 7 MISPOSITIONING IN (EXCEPT THOSE LICENSES

PRESSURIZED-WATER THAT HAVE BEEN AMENDED

REACTORS TO A POSSESSION ONLY

STATUS) OR CPs FOR NPRs

96-01 TESTING OF SAFETY-RELATED 01/10/96 ALL HOLDERS OF OLs OR

LOGIC CIRCUITS CPs FOR NPRs

95-10 RELOCATION OF SELECTED 12/15/95 ALL HOLDERS OF OLs OR

TECHNICAL SPECIFICATIONS CPs FOR NPRs REQUIREMENTS RELATED TO

INSTRUMENTATION

95-09 MONITORING AND TRAINING OF 11/03/95 ALL U.S. NRC LICENSEES

SHIPPERS AND CARRIERS OF

RADIOACTIVE MATERIALS

95-08 10 CFR 50.54(p) PROCESS FOR 10/31/95 ALL HOLDERS OF OLs &

CHANGES TO SECURITY PLANS CPs FOR NPRs WITHOUT PRIOR NRC APPROVAL

OL = OPERATING LICENSE

CP = CONSTRUCTION PERMIT

NPR = NUCLEAR POWER REACTORS

Attachment 1 GL 96-XX GL 96-05 September 18, 1996 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.

[Origina signed by]

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

2. List of Recently Issued NRC Generic Letters fi tf C "tff p4V (" ,r,(/

Tech Editor reviewed and concurred on 08/01/95 DOCUMENT NAME: 96-05.GL *SEE PREVIOUS CONCURRENCES

To receive a copy of this document, hIdicate hIthe box: 'C' = Copy w/o attachment/enclosure 'E- - Copy w/attachmentlenclosure 'N' - No copy OFFICE TECH CONT I OGC I 1C\PECB [ D\fPMl NAME TGScarbrough* SChidakel* IAChaffee* TT1aftFin DATE 05/17/96 06/10/96 05/26/96 09/i&196 OFFICIAL RECORD COP

71137

1I-)

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