ML20055G346

Ro:On 900412,engine Tripped Due to Spurious High Jacket Water Temp Trip Valve Actuation During Partial Surviellance to Verify Operability of Diesel Generator 2A.Nuclear Work Request Initiated to Repair or Replace Trip Valve

ML20055G346
Person / Time
Site:	Byron
Issue date:	06/27/1990
From:	Pleniewicz R COMMONWEALTH EDISON CO.
To:	Davis A NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
BYRON-90-0568, NUDOCS 9007230077
Download: ML20055G346 (2)

Text

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~ June 27, 1990 a-LTRt ~ BYRON 90-0568-FILE: 2.07 0400 Mr. A. Bert Davis

__ Regional Administrator Region III

.U. S. Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, IL 60137

SUBJECT:

Byron Unit 2 Operating License NPF-66, Docket No. 50-455-Reporting of Emergency Diesel Generator Failures

Dear Mr. Davis:

s report is submitted in accordance with Byron Station Unit 2 Operating ense NPF-66 Appendix A, Technical Specification 4.8.1.1.3, reporting of i..esel Generator' Failures.

This report addresses one nonvalid test and failure experienced on the 2A Diesel Generator (DG). The criteria to determine valid and nonvalid tests and

failures.is in accordance with Section C.2.e of Regulatory Guide 1.108.

.On_Apr11 12,.1990, during the performance of a partial surveillance (2BOS

-3.1.1.2.a-1) to verify operability-of the 2A DG, the engine tripped due to a spurious high jacket water temperature trip valve-actuation. The DG had been

' loaded approximately-5 minutes when the trip occurred. Local instrumentation-

' indicated that the actual jacket water temperature was slightly below 170'F.

'The high jacket water trip:setpoint,is 205'F. Since the engine was operating.

properly prior-to the trip, the engine was restarted and the operability surveillance was completed. A Nuclear Work Request was-initiated to repair or

. replace the trip valve.

The temperature trip valve was removed and bench tested. It operated at approximately 168'F. It was replaced with a trip valve with a setpoint verified ~to be 205'F. The cause for the setpoint drift out of tolerance could not be determined.

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' Byron 90-0568 b b, Page .~ 2 The'high jacket water temperature trip'is bypassed during emergency mode

<' diesel generator operations. The spurious test mode trip did not affect the 2A DO availability. . This is. classified as a nonvalid failure, and as such, does not' affect diesel generator testing frequency.

' R. Pleniewicz-T' Station Manager- 1 Byron Nuclear Powe -Station -

i RP/TGB/bf .j cci Byron Station NRC Senior Resident Inspector U.S. NRC Document Control Desk, Washington, D.C. .

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