ML20196J350

SER Accepting License Response to GL 96-05, Periodic Verification of Design-Basis Capability of Safety-Related Motor-Operated Valves

ML20196J350
Person / Time
Site:	FitzPatrick
Issue date:	12/04/1998
From:	NRC (Affiliation Not Assigned)
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Shared Package
ML20196J348	List: ML20196J343 ML20196J350
References
GL-96-05, GL-96-5, NUDOCS 9812100027
Download: ML20196J350 (8)

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2 NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 205bA001 .

SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION POWER AUTHORITY OF THE STATE OF NEW YORK RESPONSE TO GENERIC LETTER 96-05. " PERIODIC VERIFICATION OF DESIGN BASIS CAPABILITY OF SAFETY-RELATED MOTOR-OPERATED VALVES" JAMES A. FITZPATRICK NUCLEAR POWER PLANT DOCKET NO. 50-333

1.0 INTRODUCTION

Many fluid systems at nuclear power plants depend on the successful operation of motor-operated valves (MOVs) in performing their safety functions. Several years ago, MOV operating experience and testing, and research programs sponsored by the nuclear industry and the U. S. Nuclear Regulatory Commission (NRC), revealed weaknesses in a wide range of activities (including design, qualification, testing, and maintenance) associated with the performance of MOVs in nuclear power plants. For example, some engineering analyses used in sizing and setting MOVs did not adequately predict the thrust and torque required to operate valves under their design-basis conditions. In addition, inservice tests of valve stroke time under zero differential-pressure and flow conditions did not ensure that MOVs could perform their safety functions under design-basis conditions.

Upon identification of the weaknesses in MOV performance, significant industry and regulatory activities were initiated to verify the design-basis capability of safety-related MOVs in nuclear power plants. After completion of these activities, nuclear power plant licensees began establishing long-term programs to maintain the design-basis capability of their safety-related MOVs. This safety evaluation addresses tne program developed by the Power Authority of the State of New York (the licensee, also known as the New York Power Authority) to verify periodically the design-basis capability of safety-related MOVs at the James A. FitrPatrick Nuclear Power Plant.

2.0 REGULATORY REQUIREMENTS The NRC regulations require that MOVs important to safety be treated in a manner that provides assurance of theirintended performance. Criterion 1 to Appendix A, " General Design Criteria for Nuclear Power Plants," to Part 50 of Title 10 of the Code of Federal Regulations (10 CFR Part 50) states, in part, that structures, systems, and components important to safety shall be designed, fabricated, erected, and tested to quality standards commensurate with the importance of the safety functions to be performed. The quality assurance program to be applied to safety-related components is described in Appendix B,

" Quality Assurance Criteria for Nuclear Power Plants and Fuel Reprocessing Plants," to 10 CFR Part 50. In Section 50.55a of 10 CFR Part 50, the NRC requires licensees to establish inservice testing (IST) programs in accordance with Section XI of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code).

9812100027 981204 yDR ADOCK 05000333 PDR Enclosure

In response to concems regarding MOV performance, the NRC staff issued Generic Letter (GL) 89-10 (June 28,1989), " Safety-Related Motor-Operated Valve Testing and Surveillance,"

which requested that nuclear power plant licensees and construction permit holders ensure the capability of MOVs in safety-related systems to perform their intended functions by reviewing MOV design bases, verifying MOV switch settings initially and periodically, testing MOVs under design-basis conditions where practicable, improving evaluations of MOV failures and necessary corrective action, and trending MOV problems. The staff requested that licensees complete the GL 89-10 program within approximately three refueling outages or 5 years from the issuance of the generic letter. Permit holders were requested to complete the GL 89-10 program before plant startup or in accordance with the above schedule, whichever was later.

The NRC staff issued seven supplements to GL 89-10 that provided additional guidance and information on MOV program scope, design-basis reviews, switch settings, testing, periodic verification, trending, and schedule extensions. GL 89-10 and its supplements provided only limited guidance regarding MOV periodic verification and the measures appropriate to assure preservation of design-basis capability. Consequently, the staff determined that additional guidance on the periodic verification of MOV design-basis capability should be prepared.

On September 18,1996, the NRC staff issued GL 96-05, " Periodic Verification of Design-Basis Capability of Safety-Related Motor-Operated Valves," requesting each licensee establish a program, or 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. In GL 96-05, the NRC staff summarized severalindustry and regulatory activities and programs related to maintaining long-term capability of safety-related MOVs. For example, GL 96-05 discussed non-mandatory ASME Code Case OMN-1, "Altemative Rules for Preservice and Inservice Testing of Certain Electric Motor Operated Valve Assemblies in LWR Power Plants, OM Code 1995 Edition; Subsection ISTC," which allows the replacement of ASME Code requirements for MOV quarterly stroke-time testing with exercising of safety-related MOVs at least once per operating cycle and periodic MOV diagnostic testing on a frequency to be determined on the basis of margin and degradation rate. In GL 96-05, the NRC staff stated that the method in OMN-1 meets the intent of the generic letter with certain limitations. The NRC staff also noted in GL 96-05 that licensees remain bound by the requirements in their code of record regarding MOV stroke-time testing, as supplemented by relief requests approved by the NRC staff.

In GL 96-05, licensees were requested to submit the following information to the NRC:

a. within 60 days from the date of GL 96-05, a written response indicating whether or not the licensee would implement the requested actions; and

b. within 180 days from the date of GL 96-05, or upon notification to the NRC of completion of GL 89-10 (whichever was later), a written summary description of the licensee's MOV periodic verification program.

The NRC staff is preparing safety evaluations on the response of each licensee to GL 96-05.

The NRC staff intends to rely to a significant extent on an industry initiative to identify valve age-related degradation which could adversely affect the design-basis capability of safety-related MOVs (described in Section 3.0) where a licensee commits to implement that industry program.

The NRC staff will conduct inspections to verify the implementation of GL 96-05 programs at nuclear power plants as necessary.

l 3.0 JOINT OWNERS GROUP PROGRAM ON MOV PERIODIC VERIFICATION in response to GL 96-05, the Boiling Water Reactor Owners Group (BWROG), Westinghouse Owners Group (WOG), and Combustion Engineering Owners Group (CEOG) jointly developed an MOV periodic verification program to obtain benefits from the sharing of information between licensees. The Joint Owners Group (JOG) Program on MOV Periodic Verification is described by the BWROG in its Licensing Topical Report NEDC-32719, "BWR Owners' Group Program on Motor-Operated Valve (MOV) Periodic Verification," and described by the WOG and the CEOG in their separately submitted Topical Report MPR-1807, " Joint BWR, Westinghouse and Combustion Engineering Owners' Group Program on Motor-Operated Valve (MOV) Periodic Verification." The stated objectives of the JOG Program on MOV Periodic Verification are (1) to provide an approach for licensees to use immediately in their GL 96-05 programs, (2) to develop a basis for addressing the potential age-related increase in required thrust or torque under dynamic conditions, and (3) to use the developed basis to confirm, or if necessary to modify, the l applied approach. The specific elements of the JOG program are (1) providing an " interim" MOV I periodic verification program for applicable licensees to use in response to GL 96-05, (2) conducting a dynamic testing program over the next 5 years to identify potential age-related i increases in required thrust or torque to operate gate, globe, and butterfly valves under dynamic conditions, and (3) evaluating the information from the dynamic testing program to confirm or modify the interim program assumptions.

The JOG interim MOV periodic verification program includes (1) continuation of MOV stroke-time testing required by the ASME Code IST program, and (2) performance of MOV static diagnostic  !

testing on a frequency based on functional capability (age-related degradation margin over and above margin for GL 89-10 evaluated parameters) and safety significance. In implementing the interim MOV static diagnostic test program, licensees will rank MOVs within the scope of the JOG program according to their safety significance. The JOG program specifies that licensees need to justify their approach for risk ranking MOVs. In Topical Report NEDC 32264,

" Application of Probabilistic Safety Assessment to Generic Letter 89-10 Implementation," the BWROG described a methodology to rank MOVs in GL 89-10 programs with respect to their relative importance to core-damage frequency and other considerations to be added by an expert panel. In a safety evaluation dated February 27,1996, the NRC staff accepted the BWROG methodology for risk ranking MOVs in boiling water reactor nuclear plants with certain conditions and limitations. In the NRC safety evaluation (dated October 30,1997) on the JOG Program on MOV Periodic Verification, the NRC staff indicated its view that the BWROG methodology for MOV risk ranking is appropriate for use in response to GL 96-05. With respect to Westinghouse-designed pressurized water reactor nuclear plants, the WOG prepared Engineering Report V-EC-1658, " Risk Ranking Approach for Motor-Operated Valves in Response to Generic Letter 96-05."

On April 14,1998, the NRC staff issued a safety evaluation accepting with certain conditions and limitations the WOG approach for ranking MOVs based on their risk significance. Licensees not applicable to the BWROG or WOG methodologies need to justify their MOV risk-ranking approach individually.

The objectives of the JOG dynamic test program are to determine degradation trends in dynamic thrust and torque, and to use dynamic test results to adjust the test frequency and method specified in the interim program if warranted. The JOG dynamic test program includes

'(1) identification of conditions and features which could potentially lead to MOV degradation, (2) definition and assignment of valves for dynamic testing, (3) testing valves three times over a 5-year inten/al with at least a 1-year interval between valve-specific tests according to a standard

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l test specification, (4) evaluation of results of each test, and (5) evaluation of collective test results.

In the last phase of its program, the JOG will . evaluate the test results to validate the assumptions in the interim program to establish a long-term MOV periodic verification program to be implemented by licensees. A feedback mechanism will be established to ensure timely sharing of MOV test results among licensees and to prompt individual licensees to adjust their own MOV periodic verification program, as appropriate.

Following consideration of NRC staff comments, the BWROG submitted Licensing Topical Repmt NEDC-32719 (Revision 2) describing the JOG program on July 30,1997. Similar1y, the CEOG and the WOG submitted Topical Report MPR-1807 (Revision 2) describing the JOG l

program on August 6 and 12,1997, respectively. On October 30,1997, the NRC staff issued a  !

safety evaluation to the BWROG, CEOG and WOG accepting the JOG program with certain  ;

conditions and limitations as an acceptable industry-wide response to GL 96-05 for valve 1 age-related degradation. I 4.0 FITZPATRICK GL 96-05 PROGRAM 1

On November 15,1996, the licensee submitted a 60-day response to GL 96-05 notifying the  !

NRC that it would implement the requested MOV periodic verification program. On March 17,  !

1997, the licensee submitted a 180-day response to GL 96-05 providing a summary description l of the MOV periodic verification program planned to be implemented at FitzPatrick. In a submitta! dated June 2,1998, the licensee updated its commitment to GL 96-05. On October 16, l

1998, the licensee provided a response to a request for additionalinformation regarding GL 96-05 forwarded by the NRC staff on September 22,1998. l I

l in its .Util Plans to Continue Participating in JOG MOV Program as Member of BWROG & Will Implement Elements Noted in Rev 2 to TR NEDC-327|letter dated June 2,1998]], the licensee stated that it plans to continue participating in the JOG MOV Periodic Verification Program as a member of the BWROG and plans to implement the program elements described in Topical Report NEDC-32719 (Revision 2). In its submittal dated March 17,1997, the licensee described the three phases of the JOG program for implementation at FitzPatrick. The licensee stated that its then-ongoing MOV periodic verification program would be superseded by the JOG program at FitzPatrick during Refueling Outage RFO-13 (currently underway). The licensee specified that its interim MOV static diagnostic test program would commence with the testing of safety-related MOVs categorized as high risk and low margin during that outage. In its submittal dated October 16,1998, the licensee indicated that MOV ranking at FitzPatrick was assigned based on the MOV risk-ranking approach and results presented in the BWROG Topica.1 Report NEDC 32264-A and on the concems identified in the NRC safety evaluation dated February 27,1996. In its .Util Plans to Continue Participating in JOG MOV Program as Member of BWROG & Will Implement Elements Noted in Rev 2 to TR NEDC-327|letter dated June 2,1998]], the licensee identified the MOVs to undergo repetitive testing at FitzPatrick as part of the JOG dynamic test program beginning with tests during RFO-13.

5.0 NRC STAFF EVALUATION The NRC staff has reviewed the information provided in the licensee's submittals describing the program to verify periodically the design-basis capability of safety-related MOVs at FitzPatrick in response to GL 96-05. The staff also reviewed NRC Inspection Reports (irs) 50-333/93-80 and 95-20 which provided the results of inspections to evaluate the licensee's program to verify the design-basis capability of safety-related MOVs in response to GL 89-10. The NRC staff closed

the review of the GL 89-10 program at FitzPatrick in IR 50-333/95-20. The NRC staff's evaluation of the licensoe's response to GL 96-05 is described below.

5.1 MOV Program Scope in GL 96-05, the NRC staff indicated that all safety-related MOVs covered by the GL 89-10 program should be considered in the development of the MOV periodic verification program. The staff noted that the program should consider safety-related MOVs that are assumed to be capable of retuming 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.

In irs 50-333/93-80 and 95-20, the NRC staff reviewed the scope of the licensee's MOV program in response to GL 89-10 at FitzPatrick and found that the scope was consistent with GL 89-10 and its supplements. In its letter dated November 15,1996, the licensee committed to implement the requested MOV periodic verification program at FitzPatrick in response to GL 96-05 and did not take exception to the scope of the generic letter. The NRC staff considers the licensee to have made adequate commitments regarding the scope of its MOV program.

The licensee will be responsible forjustifying any deviations from the recommended scope of GL 96-05 at FitzPatrick.

5.2 MOV Assumptions and Methodologies The NRC staff expects licensees to maintain the assumptions and methodologies used in the development of its MOV programs for the life of the plant (a concept commonly described as a "living program"). For example, the design basis of safety-related MOVs will need to be maintained up to date, including consideration of any plant modifications or power uprate conditions.

In IR 50-333/95-20, the NRC staff reviewed the licensee's justification for the assumptions snd methodologies used in the MOV program in response to GL 89-10 at FitzPatrick. With certain long-term aspects discussed in the following section, the staff determined that the licensee had adequately justified the assumptions and methodologies used in its MOV program. In its letter dated October 16,1998, the licensee discussed ongoing activities, such as review of motor actuator output, to update its MOV program assumptions and methodologies. The NRC staff considers the licensee to have adequate processes in place to maintain the assumptions and methodologies used in its MOV program, including the design basis of its safety-related MOVs.

5.3 GL 89-10 Long-Term items When closing the NRC review of the GL 89-10 program at FitzPatrick, the NRC staff discussed in IR 50-333/95-20 several aspects of the licensee's MOV program to be addressed over the long tem 1. In its submittal dated October 16,1998, the licensee reported on the status of those long-term GL 89-10 aspects. For example, the licensee reviewed the NRC safety evaluation of the Electric Power Research Institute (EPRI) MOV Performance Prediction Methodology (PPM) and will evaluate the sealing thrust necessary for its Anchor / Darling double-disc gate valves prior to restart from Refueling Outage RFO-13. The licensee performed corrective actions and analyses to provide an administrative target margin of 20% forits safety-related MOVs with further review I ongoing in response to updated guidance from Limitorque Corporation on motor actuator output.

The licensee verified the design basis of several MOVs that were potentially affected by low 4

6-voltage conditions. The licensee performed an audit of its MOV program with no significant adverse findings revealed. The licensee's actions in response to GL 95-07, " Pressure Locking and Thermal Binding of Safety-Related Power-Operated Gate Valves," are being addressed by the NRC staff under a separate safety evaluation.

In irs 50-333/93-80 and 95 20, the NRC staff discussed the licensee's program for trending MOV performance at FitzPatrick by qualitative and quantitative methods. For example, the licensee reviews MOV maintenance documents and enters as-found adverse conditions and cause codes into a computerized database with the capability to trend various MOV information.

The licensee periodically evaluates this information to identify and correct recurring problems, and to detect potential MOV failures before they occur.

In IR 50-333/95-20, the staff concluded that the licensee had demonstrated the design-basis capability of its safety-related MOVs at FitzPatrick. With the licensee's ongoing MOV activities and trending program, no outstanding issues regarding the licensee's GL 89-10 program remain at FitzPatrick.

5.4 JOG Program on MOV Periodic Verification in its .Util Plans to Continue Participating in JOG MOV Program as Member of BWROG & Will Implement Elements Noted in Rev 2 to TR NEDC-327|letter dated June 2,1998]], the licensee updated its commitment to implement the JOG Program on MOV Periodic Verification as described in Topical Report NEDC-32719 (Revision 2).

In a safety evaluation dated October 30,1997, the NRC staff accepted the JOG program as an industry-wide response to GL 96-05 with certain conditions and limitations. The licensee's commitment to implement the JOG program includes (1) the JOG interim static diagnostic test program, (2) the JOG 5-year dynamic test program, and (3) the JOG long-term periodic test program. The NRC staff considers the commitments by the licensee to implement the JOG program at FitzPatrick to be an acceptable response to GL 96-05 for valve age-related degradation. The licensee is responsible for reviewing and implementing the limitations and conditions discussed in the NRC safety evaluation dated October 30,1997, in applying the JOG program at FitzPatrick. This includes the coordination and feedback of test information obtained from the JOG dynamic testing program. Where the licensee proposes to implement an approach at FitzPatrick different from the JOG program, the licensee will be expected to notify the NRC and to provide justification for the proposed attemative approach.

In its submittal dated March 17,1997, the licensee stated that the interim MOV static diagnostic test program would establish a test frequency based on the safety significance and functional capability of each GL 96-05 MOV. The MOV static diagnostic test frequency matrix at FitzPatrick is consistent with the JOG recommendations. In its submittal dated October 16,1998, the licensee reported that MOV risk ranking had been assigned at FitzPatrick based on the MOV risk-ranking approach in the BWROG Topical Report NEDC 32264-A and the concems identified in the NRC safety evaluation dated February 27,1996. For example, the licensee used importance measures referred to as Risk Achievement Worth, Risk Reduction Worth, and Fussel-Veseley, including common-cause failure events. The licensee considered the impact on Level 2 events, extemal events, and shutdown conditions. The Maintenance Rule Expert Panel at FitzPatrick reviewed the results of the analysis and made the final determination for risk ranking the MOVs. The NRC staff notes that the BWROG also provided an example list of

. risk-significant MOVs for consideration by each licensee in applying the owners group methodology. Based on the licensee's summary, the staff considers the licensee's methodology for risk ranking MOVs at FitzPatrick to be reasonable.

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7 The JOG program is intended to address most gate, globe and butterfly valves used in safety-related applications in the nuclear power plants of participating licensees. The JOG indicates that each licensee is responsible for addressing any MOVs outside the scope of applicability of the JOG program. In the NRC safety evaluation dated October 30,1997, the NRC staff specifies that licensees implementing the JOG program must determine any MOVs outside the scope of the JOG program (including service conditions) and justify a separate program for periodic verification of the design-basis capability of those MOVs. The NRC staff recognizes that the JOG .ias selected a broad rsnge of MOVs and conditions for the dynamic testing program.

Consequently, the NRC staff expects significa,4 :nformation to be obtained on the pcrformance and potential degradation of safety-related MOVs during the interim static diagnostic test program and the JOG dynamic test program. As the test results are evaluated, the JOG might include or exclude additional MOVs with respect to the scope of its program. Although the test information from the MOVs in the JOG dynamic test program might nct be adequate to establish a long-term periodic verification program for each MOV outside the scope of the JOG program, sufficient information should be obtained from the JOG dynamic test program to identify any immediate safety concem for potential valve age-related degradation during the interim period of the JOG program. Therel ore, the NRC staff considers it acceptable for the licensee to apply its interim static diagnostic test program to GL 96-05 MOVs that currently might be outside the scope of the JOG program with the feedback ofinformation from the JOG dynamic test program to those MOVs. Upon completion of the JOG dynamic test program and development of the

' JOG long-term MOV periodic verification criteria, the licensee will be expected to establish a long-term MOV periodic verification program for those MOVs outside the scope of the JOG program by applying information from the JOG program or additional dynamic tests, as necessary.

5.5 Motor Actuator Output Tl e JOG program focuses on the potential age-related increase in the thrust or torque required tc opersie valves under their design-basis conditions. In the NRC safety evaluation dated October 30,1997, on the JOG program, the NRC staff specifies that licensees are responsible for addressing the thrust or tc:que delivered by the MOV motor actuator and its potential degradation. Although the JOG does not plan to evaluate degradation of motor actuator output, significant information on the output of motor actuators will be obtained through the interim MOV s'atic diagnostic test program and the JOG dynamic test program.

In its submittal dated October 16,1998, the licensee indicated that it will use a combination of periodic static testing, data trending, and preventive mairitenance in accordance with established site procedures and programs to assure adequate actuator output capability for safety-related MOVs at FitzP:6tk to perform their design-basis functions. For example, in IR 5')-333/95-20, the NRC staff repo1ed that the ,icensee is monitoring stem friction coefficient, comparing data frorn oynam;c MOV tests with existing assumptions, and making adjustments as necessary. The staff also found that the licensee's MOV periodic verification program includes evaluation of as-found and as-left static baseline test results to monitor stem lubricant degradation. The NRC staff notes that several parameters car, be obuined during MOV static and dyn,tmic testing to help identify motor actuator output degradation when opening and closing the valve including, as applicable, capability margt .hrust and torque at control switch trip, stem friction coefficient, load sensitive behavior, and motor current. Plant-specific and JOG test information can provide support for the licensee's plan for monitoring MOV motor actuator output and its potential

degradation.

0 In Technical Update 98-01 and its Supplement 1, Limitorque Corporation provided updated guidance for predicting the torque output of its motor actuators. In its submittal dated October 16,1998, the licensee reported that it was reviewing this information for incorporation into the MOV sizing calculations at FitzPatrick. The licensee had not identified any deficiencies affecting MOV operability during its preliminary evaluations. The licensee plarv 'o complete this effort prior to restart frorrnSofueling Outage RFO-13. The licensee stated that the need for long-term MOV setpoint changes will be evaluated for action in the upcoming refueling outage or assigned to the appropriate maintenance opportunity. The NRC staff notes that the licensee will be respo,'sible for resolving any MOV operability concems in accordance with regulatory and plant-specific requirements.

l The NRC staff considers the licensee to be establishing sufficient means to monitor MOV motor j actuator output and its potential degradation.

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6.0 CONCLUSION

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! On the basis of this evaluation, the NRC staff finds that the licensee has established an acceptable program to verify periodically the design-basis capability of the safety-related MOVs at FitzPatrick. Therefore, the staff concludes that the licensee has adequately addressed the actions requested in GL 96-05. The NRC staff may conduct inspections to verify the implementation of the MOV periodic verification program is in accordance with the licensee's commitments; this NRC safety evaluation; the NRC safety evaluation dated October 30,1997, on the JOG Program on MOV Periodic Verification; and the NRC safety evaluation dated February 27,1996, on the BWROG methodology for ranking MOVs by their safety significance.

Principal Contributor: T. Scarbrough Date: December 4, 1998 l

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