ML20212A038

Ro:On 870222,solid State Protection Sys Train B Removed from Svc in Excess of 2 H Tech Spec Limit.Delay Caused by Electrical Short,Resulting in Loss of Power to One of Two Redundant Trains.Power Supply Restored

ML20212A038
Person / Time
Site:	Diablo Canyon
Issue date:	02/23/1987
From:	Thornberry R PACIFIC GAS & ELECTRIC CO.
To:	Briam W CALIFORNIA, STATE OF
References
RTR-NUREG-0654, RTR-NUREG-654 NUDOCS 8703030270
Download: ML20212A038 (2)

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PACIFIC OAS AND E LE C T RI C C O M PANY bb , DIABLO CANYON POWER PLANT

' PO. Box 56. Avila Beach, Cahtornia 93424 - (805) 595-7351 ggggggggl R.C. THORNDERRY PLANT MANAGER February 23, 1987 Mr. William Briam, County Administrator San Luis Obispo County Administrative Office County Government Center San Luis Obispo, CA 93408 J

Dear Mr. Briam:

Pursuant to NUREG-0654, Revision 1, Appendix 1, the following is a summary report concerning an Unusual Event at the Diablo Canyon Power Plant site.

At 0305 PST, February 22, 1987, Solid State Protection System (SSPS) Train B was removed from service for routine testing and to troubleshoot an indicator / lamp socket. If the duration of this testing exceeds two hours, the Technical Specifications require the Unit to be shut down. During this troubleshooting procedure, an electrical short resulted in the loss of power to one of the two redundant trains of the SSPS, delaying the return to service of SSPS beyond the two hour limitation. At 0505 PST, February 22, 1987 the Unit 1 Shift Foreman declared an Unusual Event due to a loss of engineered safety feature (the SSPS) requiring shutdown by the technical specifications. The San Luis Obispo County Sheriff's Office Watch Commander was notified at 0515 PST, February 22, 1987, and verified by the Unit 1 Shift Foreman.

Other emergency notifications were completed following the initial notification of the Sheriff.

At 0836 PST, February 22, 1987, the power supply was restored, the SSPS returned to service, and the Unusual Event was terminated. This event has in no way affected the health and safety of the public and no discharge of radioactive materials was made to the enviroment.

0703030270 070223 [.

PDH ADOCK 0500027S s PDH R.C. Thornberry g Q

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cc Mr. Benjamin P. Tong Nuclear Power Plant Planning P.O. Box 9577 Sacramento, CA 95823 Mr. John B. Martin, Administrator U.S. Nuclear Reguintory Commission, Region V 1450 Maria Lane, Suite 210 Walnut Creek, CA 94596-5368 Mr. Edward C. Williams, Sheriff San Luis Obispo County P.O. Box 32 San Luis Obispo, CA 93401 f r. George W. Knighton, Chief Licensing Branch No. 3 Division of Licensing Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission s

Washington, D.C. 20555 Director, Office of Management Information and Program Control U. S. Nuclear Regulatory Commission Washington, D.C. 20555 i

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