ML20136J285

Provides 180-day Response to GL 96-05, Periodic Verification of Design Basis Capability of SR Movs. Written Summary Description of Revised MOV Periodic Verification Program Attached

ML20136J285
Person / Time
Site:	Farley
Issue date:	03/14/1997
From:	Dennis Morey SOUTHERN NUCLEAR OPERATING CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
GL-89-10, GL-96-05, GL-96-5, NUDOCS 9703200076
Download: ML20136J285 (5)

Text

Dan M: rey S:uthern Nuclear

' Vice President Oper: ting Comptny Farley Project PO Box 1295

' Birmingham. Alabama 35201 Tel 205.992.5131 March 14, 1997 SOUTHERN COMPANY Energy ro Serve YourWorld"

$0-364 10 CFR 50.54(f)

U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Joseph M. Farley Nuclear Plant 180-Day Resoonse to Generic Letter 96-05 Ladies and Gentlemen:

Generic Letter (GL) 96-05, " Periodic Verification of Design Basis Capability of Safety-Related Motor-Operated Valves," issued on September 18,1996, requests the licensee to provide 60- and 180-day responses. This letter provides the 180-day response for Joseph M. Far'ey Nuclear Plant (FNP).

As part of the response to GL 89-10, FNP established a periodic verification program for Motor-

. Operated Valves (MOVs) which considered the knowledge available at the time. The program was revised as experience was gained during implementation of the GL 89-10 project. Southern Nuclear Operating Company (SNC) has reviewed the FNP MOV Program in light of the information contained in GL 96-05. Attached is a written summary description of the Farley MOV periodic verification program as requested by GL 96-05.

i If you have concerns relative to this matter, please contact this office.

Respectfully submitted, 2000M N D"[

Dave Morey Sworn to and subscribed before e this lhdayof Y}$$AL 1997

~0Notary Public d) .

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My Commission Expires: k6%&n u.

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MGE:mafGL96-05b. doc Attachment

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1 cc: Mr. L. A. Reyes, Region 11 Administrator l

Mr. J.1. Zimmerman, NRR Project Manager Mr. T. M. Ross, FNP Sr. Resident inspector 9703200076 970314 PDR ADOCK 05000348 P PDR u

Farley Nuclear Plant Motor-Operated Valve Periodic Verification Program Response To NRC Generic Letter 96-05

1.0 INTRODUCTION

Generic Letter (GL) 96-05, " Periodic Verification of Design-Basis Capability of Safety-Related Motor-Operated Valves," was issued September 18,1996. The generic letter requests licensees to review their existing motor-operated valve (MOV) periodic verification programs to ensure that safety-related MOVs will continue to be capable of performing their design-basis safety functions. Specifically, the generic letter requests that licensees ensure that their programs " 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."

Farley Nuclear Plant (FNP) established a periodic verification program in conjunction with the implementation of the recommendations contained in GL 89-10. The existing program was reviewed relative to the recommendations contained in GL 96-05 to ensure the program adequately addresses the concerns associated with potential inservice degradation.

The objective of this document is to summarize the periodic verification program for FNP and to identify those activities which will be undertaken to provide additional assurance that the potential for inservice degradation has been adequately addressed.

2.0 PERIODIC VERIFICATION PROGRAM The periodic verification program established in conjunction with GL 89-10 was icviewed relative to the recommendations of GL 96-05, Based on this review, it was confirmed that the periodic verification program currently in place at FNP provides adequate assurance that safety-related MOVs will continue to be capable of performing their design basis functions. Furthermore, the FNP periodic verification program is a living program, which will be reviewed and adjusted periodically based on valve performance and maintenance For periodic verification purposes, the FNP MOV Program has initiated a graded-approach for establishing both the frequency and the methods associated with periodic re-testing. The graded-approach will ensure the requisite level of confidence in MOV capability and reliability will be maintained throughout the life of the plant. Further, this approach will ensure the resources assigned to a given MOV considers pertinent aspects of each MOV including the associated risk significance and available total margin.

2.1 SCOPE The current FNP GL 89-10 program covers a tctal of 354 safety-related MOVs. The scope of valves covered by Generic Letter 96-05 is considered to be identical to that of GL 89-10.

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2.2 STATIC TEST FREOUENCY For periodic verification purposes, the FNP MOV Program has initiated a graded-approach for establishing both the frequency and the methods associated with periodic re-testing of all MOVs within the scope of GL 89-10. The graded-approach will ensure the requisite level of confidence in capability and reliability of all safety-related MOVs at FNP is maintained. 'Ihe diagnostic re-test methods will include a mixture of at-the-valve and MCC-based re-testing.

Under the graded re-test approach, the frequency of at-the-valve diagnostic re-testing will be determined by one of two methods: criteria-based or time-based. For each MOV, the criteria-based diagnostic re-test frequency includes consideration of: the safety significance; available operating margins; safety function; valve type; and setpoint basis.

4 The time-based diagnostic re-test frequency considers only the safety significance of the associated MOV.

l. The at-the-valve re-test frequency determined using the criteria-based approach can vary 1 from I cycle (18 months) to 7 cycles (126 months). Whereas, the time-based at-the-valve re-test frequencies are as follows.

Priority 1 4 cycles (72 months)

Priority 2 5 cycles (90 months)

Priority 3 7 cycles (126 months) i The actual scheduled re-test frequency for each MOV is established by comparing the i criteria-based frequency to the time-based frequency. The shortest time period is used for the at-the-valve re-test interval. l l

The frequency of MCC-based re-testing is currently established considering the safety l significance of the valves. The established MCC-based re-test frequencies are as follows. l 1

Priority 1 1 cycle (18 months)

Priority 2 3 cycle (54 months)

. Priority 3 4 cycle (72 months)

The combination of at-the-valve and MCC-based re-testing will ensure all MOVs are diagnostically re-tested at least once every 6 years (72 months).

The MOV safety significance ranking process employed at FNP utilized the existing plant probabilistic assessment capabilities and inputs from an " expert" panel. The selected

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ranking for a given MOV was the more restrictive (higher) of the ranking developed through these methods. Below is a brief description of the priority categories, which are in-part based on NUMARC document 93-05, " Guidelines for Optimizing Safety Benefits in Assuring the Performance of Motor-Operated Valves."

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1 s e Priority 1 - This is the highest category. MOVs assigned to this group were determined to have functions important for accident mitigation.

Priority 2 - His group contains MOVs having functions determined to have moderate importance with respect to accident mitigation or were identified as important to plant reliability.

Priority 3 - The function (s) of MOVs within this category were determined to have little impact on accident mitigation or plant reliability. l 2.3 MOV DIAGNOSTIC TEST EOUIPMENT  ;

1 FNP uses predominately ITI-MOVATS supplied test equipment to perform MOV periodic I testing. However, recently the Liberty Technology VOTES Torque Plug has been utilized. l l

Rising stem valves are normally tested with the ITI-MOVATS Torque Thrust Cell,

although a variety of additional sensors are available and may be utilized for measuring

! thmst and/or torque. Rotating stem valves have in the past been tested using the ITI- i d

MOVATS BARTS equipment. More recently, the VOTES Torque Plugs have been used )

, for certain valves with rotating stems; again, additional sensors are available and may be l 1 used during testing.

FNP uses the ITI-MOVATS MC-Squared (MC^2) equipment in performing MOV testing i from the motor control centers. FNP has and is continuing to assist ITI-MOVATS in performing validation testing to further expand the applicability of this equipment to additional motor types.

2.4 PERIODIC DIFFERENTIAL PRESSURE TESTING A total of 80 in-situ differential pressure tests were performed in conjunction with the implementation ofIEB 85-03 and GL 89-10. An additional 3 dynamic tests were

completed in the test loop at Wyle Laboratories. The results of this testing was used to establish valve minimum operating requirements and/or to verify the adequacy of certain

. design basis assumptions. There are no plans to perform long-term periodic differential pressure testing at FNP. l

' l As additional assurance oflong-term valve functional reliability, FNP employs target total l margins to accommodate age-related and/or stroke-dependent degradation concerns. These target margins consider the valve type and the manner in which the minimum setpoint requirements were originally determined. For example, lower margins are targeted for valves having setpoint minimum requirements determined through confidence band groupings (FNP dynamic test data) than those having minimum requirements determined via standard calculations. The target total margin values are in addition to test equipment accuracy and/or actuator repeatability.

a The amount of total margin associated with a given MOV will be formally monitored and tracked. De near-term acceptability of the field set-up of each MOV will continue to require actions to address instances of negative margins. For margin levels greater than zero but less than the target total margin, FNP will establish response guidelines by September 1,1997. These guidelines will include provisions to accelerate the satic at-the-valve re-test frequency and, under specific conditions, require the verification of the appropriate margin levels either through dynamic re-testing or the application of the EPRI PPM. The allowable time period for total margin deficiencies is dependent on the priority of the valve (s) involved.

The BWR Owners Group (BWROG) and the Westinghouse Owners Group (WOG) have  ;

joined together to sponsor the Joint Owners Group (JOG) Periodic Verification Program.

Included within this program is a differential pressure test program. The proFram objective is to demonstrate that valve intemals do not experience significant inservice degradation. The program will address gate, globe and butterfly valves.

FNP will participate in the JOG differential pressure test progran and will perfo.m different!al pressure tests on approximately four valves. The test results will undergo a preliminary evaluation on site. Once this evaluation is complete, the test data will be forwarded to the JOG Periodic Verification Program for inclusion in the overall program.

In addition, FNP will monitor the analysis, evaluation and resolution of the data collected in conjunction with the J00 dcib ential pressure test program. The results of this testing will be evaluated for applicability to FNP and will be factored into the FNP periodic verification program.

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