ML16342D318

Forwards RAI Re Response to GL 95-07, Pressure Locking & Thermal Binding of SR Power-Operated Gate Valves. Response Requested within 30 Days

ML16342D318
Person / Time
Site:	Diablo Canyon
Issue date:	06/05/1996
From:	Steven Bloom NRC (Affiliation Not Assigned)
To:	Rueger G PACIFIC GAS & ELECTRIC CO.
References
GL-95-07, GL-95-7, TAC-M93456, TAC-M93457, NUDOCS 9606060023
Download: ML16342D318 (8)

Text

rW Mr. Gregory H. Rueger Pacific Gas and Electric Company NPG Hail Code AlOD P. 0.

Box 770000 June 5,

1996 San Francisco, California 94177

SUBJECT:

REQUEST FOR ADDITIONAL INFORMATION GENERIC LETTER 95-07, "PRESSURE LOCKING AND THERMAL BINDING OF SAFETY-RELATED POWER-OPERATED GATE VALVES," DIABLO CANYON, UNITS 1

AND 2 (TAC NOS.

M93456 AND M93457)

Dear Mr. Rueger:

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 that safety-related power-operated gate valves that are susceptible to pressure locking or thermal binding are capable of performing their safety functions.

The NRC staff is reviewing and evaluating your response to GL 95-07.

Additional information, as discussed in the enclosure, is requested in order for the staff to complete its review.

We request that you respond within 30 days.

The information requested by this letter is within the scope of the overall burden estimated in Generic Letter 95-07, "Pressure Locking and Thermal Binding of Safety-Related Power-Operated Gate Valves," which was a maximum of 75 hours8.680556e-4 days <br />0.0208 hours <br />1.240079e-4 weeks <br />2.85375e-5 months <br /> per response.

This request is covered by Office of Management and Budget Clearance Number 3150-0011, which expires July 31, 1997.

Sincerely, Original signed by" Docket Nos.

50-275 and 50-323

Enclosure:

Request for Additional Information cc w/encl:

See next page f

DOCUMENT NAME:

DC93456.RAI OGC

JDyer, RIV REaton HRathbun

HWong, RIV WCFO Steven D. Bloom, Project Manager Project Directorate IV-2 Division of Reactor Projects III/IV Office of Nuclear Reactor Regulation DISTRIBUTION:

Docket File PUBLIC PDIV-2 Reading JRoe

.EAdensam WBateman SBloom it, ACRS OFC PDIV-2 LA NAME E e n

DATE 5

96 PDIV PM SB oom:

e se OFFICIAL RECORD COPY 9606060023 960605 PDR ADOCK 05000275 P

PDR gati

kk

Mr. Gregory M. Rueger Pacific Gas and Electric Company NPG - Mail Code A10D P. 0.

Box 770000 San Francisco, California 94177 June 5, 1996

SUBJECT:

REQUEST FOR ADDITIONAL INFORMATION - GENERIC LETTER 95-07, "PRESSURE LOCKING AND THERMAL BINDING OF SAFETY-RELATED POWER-OPERATED GATE VALVES," DIABLO CANYON, UNITS I AND 2 (TAC NOS.

H93456 AND H93457)

Dear Mr. Rueger:

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 that safety-related power-operated gate valves that are susceptible to pressure locking or thermal binding are capable of performing their safety functions.

The NRC staff is reviewing and evaluating your response to GL 95-07.

Additional information, as discussed in the enclosure, is requested in order for the staff to complete its review.

We request that you respond within 30 days.

The information requested by this letter is within the scope of the overall burden estimated in Generic Letter 95-07, "Pressure Locking and Thermal Binding of Safety-Related Power-Operated Gate Valves," which was a maximum of 75 hours8.680556e-4 days <br />0.0208 hours <br />1.240079e-4 weeks <br />2.85375e-5 months <br /> per response.

This request is covered by Office of Hanagement and Budget Clearance Number 3150-0011, which expires July 31, 1997.

Sincerely, Original signed by" Steven D. Bloom, Project Hanager Project Directorate IV-2 Division of Reactor Projects III/IV Office of Nuclear Reactor Regulation Docket Nos.

50-275 and 50-323

Enclosure:

Request for Additional Information cc w/encl:

See next page DOCUMENT NAHE:

DC93456.RAI OFC PDIV-2 LA PDIV PM

~RIR IIIIR Docket File PUBLIC PDIV-2 Reading JRoe EMensam WBateman SBloom ACRS OGC

JDyer, RIV REaton HRathbun

HWong, RIV WCFO NAME E e n

SB oom:

e DATE 5

96 OFFICIAL RECORD COPY

Mr. Gregory M. Rueger cc w/encl:

NRC Resident Inspector Diablo Canyon Nuclear Power Plant c/o U.S. Nuclear Regulatory Commission P. 0.

Box 369 Avila Beach, California 93424 Dr. Richard Ferguson, Energy Chair.

Sierra Club California 1100 11th Street, Suite 311

. Sacramento, California 95814 Ms. Nancy Culver San Luis Obispo Mothers for Peace P. 0.

Box 164 Pismo Beach, California 93448 Ms. Jacquelyn C. Wheeler P. 0.

Box 164 Pismo Beach, California 93448 Managing Editor The Count Tele ram Tribune 1321 Johnson Avenue P. 0.

Box 112 San Luis Obispo, California 93406 Chairman San Luis Obispo County Board of Supervisors Room 370

'ounty Government Center San Luis Obispo, California 93408 Mr. Truman Burns Mr. Robert Kinosian California Public Utilities Commission 505 Van Ness, Room 4102 San Francisco, California 94102 Mr. Steve Hsu Radiologic Health Branch State Department of Health Services Post Office Box 942732 Sacramento, California 94232 Regional Administrator, Region IV U.S. Nuclear Regulatory Commission Harris Tower

& Pavillion 611 Ryan Plaza Drive, Suite 400 Arlington, Texas 76011-8064 Christopher J.

Warner, Esq.

Pacific Gas 5 Electric Company Post Office Box 7442 San Francisco, California

94120, t

Mr. Warren H. Fujimoto Vice President and Plant Manager Diablo Canyon Nuclear Power Plant P. 0.

Box 56 Avila Beach, California 93424 Diablo Canyon Independent Safety Committee ATTN:

Robert R. Wellington, Esq.

Legal Counsel 857 Cass Street, Suite D

Monterey, California 93940

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3 Your submittal states that valves 8000A/8/C, Pressurizer PORV Block

Valves, are flexible wedge gate valves seated using torque switch bypass logic and are not susceptible to thermal binding.

The NRC staff is aware that using torque switch bypass logic to seat flexible wedge gate valves reduces the seating thrust and resultant pullout thrust.

Please provide a brief summary of diagnostic test results which supports this position.

Also, please provide the actuator thrust capability calculation results.

Through review of operational experience

feedback, the staff is aware of instances where licensees have completed design or procedural IIodifications to preclude pressure locking or thermal binding which may have had an adverse impact on plant safety due to incomplete or incorrect evaluation of the potential effects of these modifications.

Please describe evaluations and training for plant personnel that have been conducted for each design or procedural modification completed to address potential pressure locking or thermal binding concerns.

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