ML20011E321

Special Rept:On 891227,pressurizer Base Support Strong Motion Accelerometer 2XT-8020D Declared Inoperable for More than 30 Days Due to Playback Readings Outside Test Acceptance Criteria.Repairs Planned During Next Outage

ML20011E321
Person / Time
Site:	San Onofre
Issue date:	02/01/1990
From:	Nandy F SOUTHERN CALIFORNIA EDISON CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NUDOCS 9002130218
Download: ML20011E321 (2)

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.U. S. Nuclear _ Regulatory Commission Document Control Desk Washington, D.

C.

20550

Subject:

Docket No. 50-361 l

Special Report l

San Onofre Nuclear Generating Station, Unit 2 l

The purpose of this letter-is to provide.the Special Report required by i

Technical Specification 3.3.3.3, Action "a" of Facility Operating License NPF-10 for San Onofre Nuclear Generating Station, Unit 2, for scismic l

instrument 2XT-8020D being inoperable for greater than 30 days.

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.On December 27, 1989, with Unit 2 in Mode 1 at 100% power, pressurizer i

base support, strong motion accelerometer (SMA) 2XT-8020D was declared inoperable following. performance of a routine 6-month surveillance test due to the failure of the SMA to meet certain requirements of Procedure SO23-II-2.1.

Specifically, the longitudinal sensor playback readings of SMA 2XT-8020D were outside the test acceptance criteria.

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Investigation results to date have not been able to establish when the SMA failed.

Troubleshooting of the seismic instrumentation components and circuitry could not determine the cause of the deficiency.

Further troubleshooting would have re. quired containment entry to physically r

access 2XT-8020D.

Due to AIARA considerations during power operations,-

personnel are precluded from performing further investigative efforts.

Planned troubleshooting and repair efforts for 2XT-8020D are scheduled during the next Mode 4 outage of sufficient duration.

i 9002130218 900201 7

PDR ADOCK 05000361 s

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Document Control Desk February 1, 1990 i

i If you require any additional'information, please let me know.

Very truly yours, i

i cc:

J. B. Martin (Regional Administrator, NRC Region V)

C. W. Caldwell (NRC Senior Resident Inspector, Unito 1, 2 and 3)

Institute of Nuclear Power Operations (INPO) t I

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