ML20237H014

Special Rept:On 870707,fire Detection Instrumentation for Fire Zone 8 Removed from Svc.While Performing Maint,Spurious Alarms Received.Caused by Failed Circuit Boards.Boards Replaced.Zone 8 Returned to Svc on 870807

ML20237H014
Person / Time
Site:	San Onofre
Issue date:	08/19/1987
From:	Morgan H SOUTHERN CALIFORNIA EDISON CO.
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
NUDOCS 8708240333
Download: ML20237H014 (2)

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,; ws Southem Califomia Edison Company SAN ONOFRE NUCLE AR GENERATING ST ATION P O BOX t20 6AN CLEMENTE. CALIFORNIA 92672 ST AT ON 84ANAC I? 68 6 49

- August 19, 1987' U.S. Nuclear Regulatory Commission Document Control Desk Washington,.D.C. 20555

Subject:

Docket No. 50-206 Special Report San Onofre Nuclear Generating Station, Unit 1 Pursuant to Section 3.14.B.4.b of' Appendix A, Technical Specifications to Provisional Operating License DPR-13 for San Onofre Unit 1, this submittal provides the required Special Report for Fire Detection Instrumentation being inoperable for greater than 14 ' days.

On July 7,1987, Fire Detection Instrumentation for fire zone 8 was removed from

. service to perform planned maintenance including cleaning of detectors and semi-annual functional testing required by Technical Specification 4.15.D.(1).

As this work progressed, computer alarms associated with zone 8 and other fire detection zones were received. As a result, maintenance was expanded to include

. troubleshooting of fire detector circuitry, data gathering panels (DGP) and  ;

associated computer circuitry. This effort required isolating fire zone detector-circuitry from the computer, essentially rendering various fire detection instrumentation inoperable.

Compensatory 1-hour fire watch patrols were initiated for zone 8 in accordance

-with Technical Specification 3.14.B.4.a, on July 7, and as the instrumentation for other zones was removed from service. ,

The spurious alarms were due to failed circuit boards in the Fire Computer System transmitting units (N-modules). The failed circuit boards have been replaced.

Zone 8 and all other affected fire detection instrumentation were returned to scrvice on August 7,1987, following satisfactory functional testing. ,

8708240333 870019 PDR ADOCK 05000206 g PDR t

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's DEcument Control Desk -- 2 u ,

=If 'you require additional information, please so advise.

Sincerely, "N

cc: J.'B. Martin (Regional Administrator, USNRC Region V)

F. R. Huey (USNRC Resident Inspector, Units 1, 2 and 3)

Institute of Nuclear Power Operations-(INP0)'

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