U-600941, Special Rept:On 870411,operator Discovered No Power to Play Back Pens (All Lights Out) of Playback Unit.Caused by Blown Fuses of Recorder,Playback & Analyzer.Sensor & Portion of Circuit Boards Have Been Replaced

Special Rept:On 870411,operator Discovered No Power to Play Back Pens (All Lights Out) of Playback Unit.Caused by Blown Fuses of Recorder,Playback & Analyzer.Sensor & Portion of Circuit Boards Have Been Replaced

ML20235E471
Person / Time
Site:	Clinton
Issue date:	05/21/1987
From:	Spangenberg F ILLINOIS POWER CO.
To:	Davis A NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
U-600941, NUDOCS 8707110075
Download: ML20235E471 (2)

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e4-U-600941 L30-87 (05 -21 )-L l 1A.120 ILLINDIS POWER OOMPANY IP CUNToA PontR ST ATies P o BCs 678 CUNTON iLUNo4 E1727 May 21, 1987 i

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i Docket No. 50-461 i Mr. A. B. Davis Acting Regional Administrator Region III U.S. Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, Illinois 60137

Subject:

Special Report: Inoperability of Seismic Monitoring Instrumentation l

Dear Mr. Davis:

This Special Report is submitted pursuant to CPS Technical' Specification 6.9.2 in accordance with the ACTION statement specified per Technical Specification Limiting Conditions for Operation 3.3.7.2. The l ACTION requires the preparation and submittal of a Special Report when one or more of the seismic monitoring instruments are inoperable for more than 30 days. Accordingly, this report outlines the cause of the condition and ,

I the plans for restoring the instrument to operable status.

The condition was discovered on April 11, 1987, when the control room operator observed that there was no power to the playback pens (all lights

) out) of the playback unit as he tried to perform the functional test for the seismic instrumentation. A noncompliance with the Limiting Condition for Operation was declared at 1400.

Immediate investigation revealed that the 12V power supply fuses to' j the recorder, playback and analyzer unit were blown. Troubleshooting was thus performed to determine the cause of the blown fuses. -It was l  !

subsequently discovered that a sensor had shorted out and that several circuit boards had failed. The sensor, which is located several feet I

underground outside the plant, was subsequently uncovered and inspected. ]

j The sensor appeared burned out, and lightning damage is suspected as the j possible cause of the failure since the sensor is located near a microwave tower. It is believed that the circuit boards were damaged when the sensor was damaged.

1 The sensor and a portion of the circuit boards have been replaced. '

There were no spares on site for some of the failed boards, so replacement boards had to be ordered for them. The estimated shipping date for the replacement boardt is June 1, 1987.

Functional testing to verify ' system operability will be fully completed when the boards have been installed.

S' 8707110075 870521 PDR

/J- I n F

ADOCK 05000461 S PDR

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' U-6009t.1 l L30-E7 (05 -21 )-L 1A.120 In addition to the action required for returning the instrumentation to operable status, an investigation has been initiated to address the prevention of lightning damage to the sensor in the future. A preliminary report from Sargent & Lundy is due to Illinois Power May 22, 1987 and will provide recommendations on which an engineering evaluation will be based.

Sincerely yours, 1

F. A. Spangenberg l Manager - Licensing and Safety l l

TBE/cke 1 cc: B. L. Siegel, NRC Clinton Licensing Project Manager NRC Resident Office Illinois Department of Nuclear Safety Document Control Desk l

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