ML20205G585

Forwards RAI Re Licensee 960214 Submittal of 180-day Response to GL 95-07, Pressure Locking & Thermal Binding of Safety-Related Power-Operated Gate Valves, for Plant. Response Requested within 120 Days of Receipt of Ltr

ML20205G585
Person / Time
Site:	Wolf Creek
Issue date:	04/01/1999
From:	Thomas K NRC (Affiliation Not Assigned)
To:	Maynard O WOLF CREEK NUCLEAR OPERATING CORP.
References
GL-95-07, GL-95-7, TAC-M93540, NUDOCS 9904070299
Download: ML20205G585 (4)

Text

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.. a l i April 1, 1999 Mr. Otto L. Maynard .

4 President and Chief Executive Officer Wolf Creek Nuclear Operating Corporation Post Office Box 411 Burlington, Kansas 66839 .

SUBJECT:

REQUEST FOR ADDITIONAL INFORMATION (RAl) REGARDING WOLF I CREEK GENERATING STATION (TAC NO. M93540)

Dear Mr. Maynard:

On August 17,1995, the NRC issued Generic Letter (GL) 95-07, " Pressure Locking and Thermal Binding of Safety-Related Power-Operated Gate Valves," to request that licensees take actions to ensure those safety-related power-operated gate valves that are susceptible to '

pressure locking or thermal binding are capable of performing their safety functions.

By letter dated February 14,1996, Wolf Creek Nuc!aar Operating Corporation (WCNOC) submitted its 180-day response to GL 95-07 for Wolf Creek Generating Station (WCGS). The NRC staff reviewed WCNOC's submittal and requested additional information in a letter dated May 30,1996. By letter dated July 3,1996, WCNOC provided the additionalinformation. -

The staff has reviewed WCNOC's submittals and has determined that additional information is needed to complete the review. The information needed is detailed in the enclosure. We request that you respond to the RAI in writing within 120 days of receipt of this letter. The RAI and schedule for your response were discussed with Mr. Tony Harris of your staff on March 17, i 1999.

I If you have any questions, please contaci me at (301) 415-1362.

Sincerely, ORIG. SIGNED BY Kristine M. Thomas, Project Manager, Section 2 Project Directorata IV & Decommissioning Division of Licensing Project Management  !

Office of Nuclear Reactor Regulation I i i

l Docket No. 50-482 DISTRIBUTION:

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....,f April 1, 1999 l Mr. Otto L. Maynard President and Chief Executive Officer Wolf Creek Nuclear Operating Corporation Post Office Box 411 Burlington, Kansas 66839

SUBJECT:

REQUEST FOR ADDITIONAL INFORMATION (RAI) REGARDING WOLF CREEK GENERATING STATION (TAC NO. M93540)

Dear Mr. Maynard:

On August 17,1995, the NRC issued Generic Letter (GL) 95-07, " Pressure Locking and Thermal Binding of Safety-Related Power-Operated Gate Valves," to request that licensees take actions to ensure those safety-related power-operated gate valves that are susceptible to pressure lock'ng or thermal binding are capable of performing their safety functions.

By letter dated February 14,1996, Wolf Creek Nuclear Operating Corporation (WCNOC) l submitted its 180-day response to GL 95-07 for Wolf Creek Generating Station (WCGS). The NRC staff reviewed WCNOC's submittal and requested additional information in a letter dated May 30,1996. By letter dated July 3,1996, WCNOC provided the additional information.

The staff has reviewed WCNOC's submittals and has determined that additional information is nesded to complete the review. The information needed is detailed in the enclosure. We request that you respond to the RAI in writing within 120 days of receipt of this letter. The RAI and schedule for your response were discussed with Mr. Tony Harris of your staff on March 17, j 1999. j If you have any questions, please contact me at (301) 415-1362. 1 Sincerely, i l

W cnTW l Kristine M. Thomas, Project Manager, Section 2 '

Project Directorate IV & Decommissioning Division of Licensing Project Management Office of Nuclear Reactor Regulation  !

Docket No. 50-482

Enclosure:

Request for AdditionalInformation i cc w/ encl: See next page L

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Wolf Creek Generating Station

! cc w/ encl:

Jay Silberg, Esq. Chief Operating Officer Shaw, Pittman, Potts & Trowbridge Wolf Creek Nuclear Operating Corporation l 2300 N Street, NW P. O. Box 411 l Washington, D.C. 20037 - Burlington, Kansas 66839 l Regional Administrator, Region IV Supervisor Licensing U.S. Nuclear Regulatory Commission Wolf Creek Nuclear Operating Corporation

, 611 Ryan Plaza Drive, Suite 1000 P.O. Box 411 l Arlington, Texas 76011 Burlington, Kansas 66839 l

Senior Resident inspector U.S. Nuclear Regulatory Commission U.S. Nuclear Regulatory Commission Resident Inspectors Office P, O. Box 311 8201 NRC Road Burlington, Kansas 66839 Steedman, Missouri 65077-1032 Chief Engineer Utilities Division Kansas Corporation Commission 1500 SW Arrowhead Road Topeks, Kansas 66604-4027 Office of the Governor State of Kansas Topeka, Kansas 66612 Attomey General Judicial Center 301 S.W.10th 2nd Floor Topeka, Kansas 66612 County Clerk Coffey County Courthouse Burlington, Kansas 66839 Vick L. Cooper, Chief Radiation Control Program Kansas Department of Health and Environment Bureau of Air and Radiation Forbes Field Building 283 Topeka, Kansas 66620 l

, s REQUEST FOR ADDITIONAL INFORMATION RESPONSE TO GENERIC LETTER 95-07. " PRESSURE-LOCKING AND THERMAL-BINDING OF SAFETY-RELATED POWER-OPERATED GATE VALVES" WOLF CREEK GENERATING STATION DOCKET NO. 50-482

1. WCNOC's submittal dated July 3,1996, states that the charging pump discharge to I the reactor coolant system (RCS) cold leg injection valves, EMHV 8801 A/B and EMHV 8803A/B, are not susceptible to pressure locking because a charging pump is operating when the valves open. Are EMHV 8801 A/B sequenced to open after EMHV 8803A/B are open or could EMHV 8801 A/B operate at locked rotor conditions until EMHV 8803A/B is initially open? On a loss of off-site power, are these valves sequenced to open after the charging pumps restart or could the valves operate at locked rotor conditions until the charging pumps develop full discharge pressure?

Either clarify the basis or provide appropriate actions to ensure that pressure locking is not a concern for these valves. If applicable, explain why it is acceptable for these valves to operate at locked rotor conditions.

2. WCNOC's submittal dated July 3,1996, states that operational experience obtained during plant cooldowns demonstrates that the pressurizer power operated relief valve (PORV) block valves, BBHV 8000A/B, are not susceptible to pressure locking. The NRC staff notes that after long periods of time, the pressure in the valves will decay and the valves will not pressure lock; therefore, the operational expericnce obtained during cooldown does not demonstrate that BBHV 8000A/B will not pressure lock during a steam generator tube rupture (SGTR) event. These valves are a pressure I locking concern at other Westinghouse plants for SGTR events. Either clarify the basis or provide appropriate actions to ensure that pressure locking is not a concern for these valves.

1

3. WCNOC's submittal dated July 3,1996, provided the calculations (Commonwealth Edison (Comed) methodology) that demonstrated that the following valves would operate during pressure-locking conditions:

EJHV 8811A/B Residual Heat Removal Pump Containment Sump Suction EMHV 8802A/B Safety injection Pump to RCS Hot Leg injection ENHV 0001 Containment Spray Pump Containment Sump Suction ENHV 0007 Containment Spray Pump Containment Sump Suction Comed recommends that, when using its methodology, minimum margins should be applied between calculated pressure-locking thrust and actuator capability. These margins along with diagnostic equipment accuracy and methodology limitations are defined in a letter from Comed to the NRC dated May 29,1998 (Accession Number

l 9806040184). Explain how WCNOC is incorporating these Comed recommendations into the calculations used to demonstrate that EJHV 8811NB, EMHV 8802NB, ENHV 0001 and ENHV 0007 will operate during pressure-locking conditions. Also, discuss if the valve factors, stem factors and actuator capability at reduced voltages are the same values as those used in WCNOC's GL 89-10,

" Safety-Related Motor-Operated Valve Testing and Surveillance," program and how WCNOC determined maximum bonnet pressures.

4. WCNOC's technical specifications require an operable emergency core cooling system injection flow path from the refueling water storage tank (RWST) to the RCS via the residual heat removal (RHR) pump when RCS temperature is less that 350*F, During the shutdown cooling mode of operation, the RHR pump suction valve to the RWST, BNHV 8812A or B, is shut. Is the valve required to be opened to realign the

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RHR pump to inject into the RCS? If so, explain why the valve is not susceptible to hydraulic and therma' induced pressure locking?

5. Explain why the RHR to charging and safety injection (SI) pumps' suction valves, EJHV 8804NB, and RHR to SI pump suction valves, EMHV 8807NB, are not susceptible to hydraulic and thermalinduced pressure locking. The bonnets of these valves could be pressurized during the shutdown cooling and RHR pump surveillance and injection modes of operation and these valves would be required to open later when pressure in the bonnets of the valves is greater than upstream and downstream pressures.

6. Explain why containment spray pump discharge valves, ENHV 0006 and ENHV 0012, and spray additive eductor isolation valves, ENHV 0015 and ENHV 0016, are not susceptible to pressure locking following containment spray pump testing.