ML19323F150

RO 80-031/01T:on 800521,while Energizing RHR motor-operated Isolation Valves,Suction Valve Closed.Caused by False High Pressure Signal Input Due to de-energized Instrument Loop. RHR Pump Shut Down.Sys Isolated for Repairs

ML19323F150
Person / Time
Site:	Beaver Valley
Issue date:	05/21/1980
From:	Werling J DUQUESNE LIGHT CO.
To:
References
BVPS:JAW:867, NUDOCS 8005280593
Download: ML19323F150 (2)

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Post Office Box 4 Shippingport, PA 15077 tby 21, 1980 BVPS: JAW:867 Beaver Valley Power Station, Unit No. 1 Docket No. 50-334, License No. DPR-66 LER 80-031/01T Mr. B. H. Crier, Director of Regulation United States Nuclear Regulatory Co= mission Region 1 631 Park Avenue King of Prussia, Pennsylvania 19406 s

Dear Mr. Crier:

In accordance with Technical Specification 3.4.1.1, Reactor Coolant Loops, the following occurrcnce is reported. This occurrence was reported to Mr. J. D. Hegner, the Beaver Valley NRC Resident Inspector; at 0815 hours33.958 days <br />4.851 weeks <br />1.116 months <br /> on May 21, 1980. .

At 0300 hours12.5 days <br />1.786 weeks <br />0.411 months <br /> on May 21, 1980 during a routine containment tour, the operator noticed a leaking weld on a high point vent nipple. The leak was tcported to the Shift Supervisor who then made preparation to energize the motor-operated isolation valves. The RHR system was to be left in service with a means of isolation until a method to repair the leak was formulated. Plant operators were energizing the Residual Heat Removal System (RHR) motor-operated isolation valves to facilitate RHR isolation if necessary. When the operator energized the suction valve, it immediately closed, resulting in a loss of RllR flow. The reason that the isolation valves closed when energized was due to a t'alse high pressure signal input because the instrument loop was deenergized.

RHR flow was restored at 0554 hours23.083 days <br />3.298 weeks <br />0.759 months <br />. At 0933 hours38.875 days <br />5.554 weeks <br />1.278 months <br />, the RHR pump was shutdown and the system isolated to make temporary wcId repairs. Total RHR flow was restored after the wcld repair at 1412 hours58.833 days <br />8.405 weeks <br />1.934 months <br />.

. gY W #i T2 8005280 573 -

e Mr. B. H. Crier -

May 21, 1980 .

BVPS: JAW:867 .

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The safety implications were minimal because 16akage was contained and the RilR system was capabic of isolation in case of gross failure.

Very truly yours,

{st/ .

J. A. Werling Superintendent cc: Director Of Management & Program Analysis..h#'

United States Nucicar Regulatory Commission Washington, D. C. 20555 D. L. Wigginton, BVPS Licensing Project Manager United States Nuclear Regulatory Commission Washington, D. C. 20555 ,

D. A. Beckman, Nuclear Regulatory Commission, BVPS Site Inspector C. A. Olson, Secretary, Prime Movers Committee - EEI Mr. C. J. Six, PA Public Utilities Commission, Harrisburg, PA

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