ML17279A257

Advises That Util Required to Implement Appropriate Mods to Isolation Valves RHR-V-8 & RHR-V-9 to Meet Objectives of App R to 10CFR50 Re Prevention of LOCAs at High/Low Pressure Interfaces.Submittal of Schedule Requested

ML17279A257
Person / Time
Site:	Columbia
Issue date:	05/13/1987
From:	Knighton G Office of Nuclear Reactor Regulation
To:	Sorensen G WASHINGTON PUBLIC POWER SUPPLY SYSTEM
References
TAC-63528, NUDOCS 8705180425
Download: ML17279A257 (8)

Text

Docket No. 50-397 G.

C. Sorensen, Manager Regulatory Programs Washington Public Power Supply System P.O.

Box 968 3000 George Washington Way Richland, Washington 99352

Dear Mr. Sorensen:

DISTRIBUTION NRC/L PDR DMCrutchfield GMHolahan RSamworth/JLee OCG-Bethesda EJordan/JPartlow ACRS (10)

JRidgely Thadani Wermiel Craig

Subject:

COMPLIANCE WITH RE(UIREMENTS OF APPENDIX R TO 10 CFR PART 50 RELATING TO PREVENTION OF LOCAS AT HIGH/LOW PRESSURE INTERFACES.

(TAC 863528)

We are writing to reinform you of the NRC staff position and required action on the issue of spurious opening of high/low pressure interface valves during fires to meet the objective of Appendix R.

Your attention is directed specifically to the valves identified as RHR-V-8 and RHR-V-9 on the RHR suction line.

We are advising you that we require WPPSS to implement appropriate modifications to these isolation valves aC soon as practical to meet the objectives of Appendix R to 10 CFR Part 50.

We would hope that this can be done prior to restart following the current 1987 refueling outage.

By this letter we request that you advise us of modifications which WPPSS will make to ensure isolation and provide us with a schedule for completion of those modifications.

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In correspondence to you dated October 20, 1986, NRC asked that WPPSS "document your committment to remove the power from the RHR-V-8 valve during non-shutdown operating condition" and that you "provide a schedule and a

justification for the schedule" for doing so.

Your response, dated December 1, 1986, to that letter instead referenced the position set forth in your letter of July 16, 1986 (that "the Supply System feels that the design should remain as is").

Appendix R to 10 CFR Part 50, Section III.L.1, concerning postfire alternate shutdown, specifically states that "during the postfire shutdown... there shall be no fuel cladding

damage, rupture of any primary coolant boundary, or rupture of the containment boundary."

One specific area of concern regarding protection of the primary coolant boundary is the high/low pressure interface.

The high/low pressure interface is the junction of piping at isolation valves which separate piping designed for full reactor pressure on one side from piping designed for low pressure service on the other side.

The concern with the high/low pressure interface is that because the low pressure side of the valves is not designed for operation at the normal operating pressure of the reactor, if the valves were to open (such as could result

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C. Sorensen from fire-induced spurious signal) when the reactor is at pressure, the low pressure piping could rupture.

Further, fire damage may also result in an inability to close the isolation valves resulting in an unisolatable LOCA outside of containment.

For the Appendix R review, it is postulated that a fire in the control room could result in spurious opening of valves RHR-V-8 and RHR-V-9 which would create an unisolatable LOCA outside the containment, thus violating two of the three aforementioned 10 CFR Part 50 Appendix R req'uirements.

The, consequence of this accident would be significant and could adversely affect the health and safety of the public.

Furthermore, we are not aware of any plant that has not removed power from one of the RHR suction line isolation valves or has not provided other modification outside of the control room fire area to preclude the valve from opening.

Amendment 37 to the WNP-2 FSAR, which you submitted to the NRC on September 22, 1986, states that "during normal plant operation, power is removed from valve RHR-V-8... to assure that inadvertent opening will not occur."

The staff finds that this approach constitutes adequate compliance with the Appendix R requirement.

We recognize that alternative modifications could also achieve compliance.

We are informing you of our requirement on this item in advance of our completion of our review of Amendment 37 because of the importance of the fire protection issues and because the current outage may provide an opportune time for taking the corrective actions described in this portion of Amendment 37. If other alternatives are to be used an amendment to the FSAR describing the change must be provided on the docket.

We are prepared to discuss this as necessary to expedite action within the current refueling outage.

Sincerely, 7

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.Gt.orge N. Kai1 htOn George W. Knighton, Director Project Directorate V

Division of Reactor Projects - III/IV/V 5 Special Projects cc:

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from fire-induced spurious signal) when the reactor is at pressure, the low pressure piping could rupture.

Further, fire damage may also result in an inability to close the isolation valves resulting in an unisolatable LOCA outside of containment'.

For the Appendix R review, it is postulated that a fire in the control room could result in spurious opening of valves RHR-V-8 and RHR-V-9 which would create an unisolatable LOCA outside the containment, thus violating two of'he three aforementioned 10 CFR Part 50 Appendix R requirements.

The consequence of this accident would be significant and could adversely affect the health and safety of the public.

Furthermore, we are not aware of any plant that has not removed power from one o'f the RHR suction line isolation valves or has not provided other modification outside of the control room fire area to preclude the valve from opening.

Amendment 37 to the WNP-2 FSAR, which you submitted to the NRC on September 22, 1986, states that "during normal plant operation, power is removed from valve RHR-V-8... to assure that inadvertent opening will not occur."

The staff finds that this approach constitutes adequate compliance with the Appendix R requirement.

We recognize that alternative'modifications could also achieve compliance.

1, I am informing you of our requirement on this item in advance of our completion of our review of Amendment 37"because of the importance of the fire protection issues and because the current outage may provide an opportune time for taking the corrective actions described in this portion of Amendment 37.

We are prepared to discuss this as necessary to expedite action within the current refueli'ng outage.

Sincerely, George W. Knighton, Director Project Directorate V

Division of Reactor Projects - III/IV/V 5 Special Projects cc:

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Nr. G: C. Soreni, Nanager Washington Public Power Supply System KPPSS ttuclear Project tto.

2 (eP-2) cc: Nicholas S. Reynolds, Esq.

Bishop, Lfberman,

Cook, Purcell 5 Reynolds Seventeenth

Street, N.W.

Washington, D.C.

20036 Nr. G. E. Doupe, Esquire Mashington Public Power Supply System P. 0.

Box 968 3000 George Mashington May Richland, Mashfngton 99532 Nr, Curtis Eschels, Chairman Energy Facility Site Evaluation Councfl

'ail Stop PY-ll Olympia, Washington 98504 L. Powell, Licensing Nanager Washington Public Power Supply System P. 0. Box 968, ND 9568 Richland, Washington 99352 Hr. M. G. Conn Burns and Roe, Incorporated c/o Mashington Public Power Supply System P. 0. Box 968, HD 994E Rfchland, Washington 99352 R. B. G'lasscock, Director Licensing and Assurance Mashington Public Power Supply System P. 0. Box 968, ND 280 Richland, Mashington 99352 Nr. C. N. Powers MNP-2 Plant Nanager Washington Public Power Supply System P. 0. Box ND 927M Richland, Mashington 99352 Regional Administrator, Region V

U.S. Nuclear Regulatory Coamission 1450 Naria Lane, Suite 210 1200 Walnut Creek, Calf fornfa 94596

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