05000219/LER-1981-055, Forwards LER 81-055/03L-0.Detailed Event Analysis Encl

Forwards LER 81-055/03L-0.Detailed Event Analysis Encl

ML20038B488
Person / Time
Site:	Oyster Creek
Issue date:	11/30/1981
From:	Carroll J JERSEY CENTRAL POWER & LIGHT CO.
To:	Haynes R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML20038B489	List: 05000219/LER-1981-055, Forwards LER 81-055/03L-0.Detailed Event Analysis Encl 05000219/LER-1981-055-03, /03L-0:on 811031,investigated No or Low Response by Two Acoustic Monitoring Sys Channels for Position Indication of Safety & Relief Valves.First Caused by Broken Cable at Accelerometer,Second by Accelerometer Malfunction
References
NUDOCS 8112080333
Download: ML20038B488 (3)

LER-1981-055, Forwards LER 81-055/03L-0.Detailed Event Analysis Encl

Event date:
Report date:
2191981055R00 - NRC Website

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OYSTER CREEK NUCLEAR GENERATING STATION N

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Novenber 30, 1981 Mr. Ronald Haynes, Director Office of Inspection and EnforceTent Region I United States Nuclear Regulatory Camission 631 Park Avenue King of Prussia, Pennsylvania 19406

Dear Mr. Haynes:

SUBJECT: Oyster Creek Nuclear Generating Station Docket No. 50-219 Licensee Event Report Reportable Occurrence No. 50-219/81-55/3L l

This letter forwards three copies of a Licensee Event Report to report Reportable Occurrence No. 50-219/81-55/3L in empliance with paragraph 6.9.2.b.2 of the Technical Specifications.

Very truly yours,

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. T. Carroll, Jr.

Acting Director Oys Crmk JIC:dh Enclosures m

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)w United States Nuclear Regulatory Camission Washington, D. C. 20555 NRC Resident Inspector (1)

Oyster Creek Nuclear Generating Station Forked River, N. J.

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3 OYSTER CREEK NUCLEAR GDERATING STATION Forked River, New Jersey 08731 Licensee Event Report Rep rtable Occurrence No. 50-219/81-55/3L Report Date Noverber 30, 1981 Occurrence Date October 31, 1981 Identification of Occurrence The Acoustic bbnitoring Systen (NE) for safety and relief valve position indication was found to have two channels that provided no or low response.

Acoustic nonitors are required by Technical Specification paragraph 3.13.A.l.

This event is considered to be reportable as defined in the Technical Speci-fications, paragraph 6.9.2.b.2.

Conditions Prior to Occurrence Plant was in cold shutdown condition when the failure was recognized.

Description of Occurrence During reactor operation, prior to shutdown, an investigation into noise indication on two other acoustic nonitors was perfonned. The investigation indicatcd that the acoustic nonitors were operable. On Saturday, October 31, 1981, an entry into the drywell to further investigate the AMS perfonnance revealcd the following equiptent failures: The NE channel for safety valve NR28C was found to have a broken cable at the acceleraneter and a channel for relief valve NR108B was found to have a bad accelerareter. Operability of all NE channels was required in the Startup and Run Mode of the plant operation per T.S. paragraph 3.13,A.l.

Apparent Cause of Occurrence The cause of failure for the AMS channel for safety valve NR28C was attributed to the broken cable at the accelerometer. The cause of tal08B Acoustic Monitor failure was due to the accelerometer malfunction. At the time of discovery, the plant was shutdown for reasons other than the suspected malfunction of AMS channels.

Analysis of Occurrence The NE provides position indication of the safety and relief valves and is considered to be accident nonitoring instrumentation. Valve open position is alarmed in the Control Boan by the AMS. A failure of safety or relief valve to close fran its open position mnstitutes a small break IOCA and the NE alerts the Control Roan operator of such an event.

Reportable Occurrence Page 2 Report No. 50-219/81-55/3L The failure of two AMS channels to provide the respective valve position in-dication degraded the accident nonitoring capability, however, the operator still had backup instrumentation (thernoccuples) per T.S. paragraph 3.13,A.1 (Table 3.13.1) that would provide the trend of valve tail pipe tauperature. In addition, an inference can be made fran the reactor pressure and level instru-mentation as to whether or not the valve asecciated with the failed channel has closed. Therefore, failure of two NE channels would not have resulted in an undetectable transient. In addition, adjacent acoustic nonitors would detect a failed open valve and possibly actuate the alarm. The safety significance, therefore, is considered minimal.

Corrective Action

The broken cable in the NE channel for safety valve NR28C and the bad accelero-neter in the channel for relief valve NR108B were replaced. All channels were tested and found to be satisfacto.n.f. Trouble shooting and performance evaluation techniques were inproved following this event and will be incorporated into existing or new procedures.

Failure Data The N E is supplied by Babcock & Wilcox.

Reference: B & W Technical Manual #BAW-1587, Rev. 1, February 1980 L