05000334/LER-1980-047-03, /03L-0:on 800805,during Exercise Mode,Emergency Diesel Generator Output Circuit Breaker Failed to Close. Caused by Relay Latch Inoperability,Due to Dirty Contacts. After Replacing Contact Block,Diesel Tested Satisfactorily

/03L-0:on 800805,during Exercise Mode,Emergency Diesel Generator Output Circuit Breaker Failed to Close. Caused by Relay Latch Inoperability,Due to Dirty Contacts. After Replacing Contact Block,Diesel Tested Satisfactorily

ML19344F080
Person / Time
Site:	Beaver Valley
Issue date:	09/04/1980
From:	Lacey W DUQUESNE LIGHT CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML19344F077	List: 05000334/LER-1980-047, Forwards LER 80-047/03L-0 05000334/LER-1980-047-03, /03L-0:on 800805,during Exercise Mode,Emergency Diesel Generator Output Circuit Breaker Failed to Close. Caused by Relay Latch Inoperability,Due to Dirty Contacts. After Replacing Contact Block,Diesel Tested Satisfactorily
References
LER-80-047-03L, LER-80-47-3L, NUDOCS 8009120386
Download: ML19344F080 (2)

LER-1980-047, /03L-0:on 800805,during Exercise Mode,Emergency Diesel Generator Output Circuit Breaker Failed to Close. Caused by Relay Latch Inoperability,Due to Dirty Contacts. After Replacing Contact Block,Diesel Tested Satisfactorily

Event date:
Report date:
3341980047R03 - NRC Website

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Attachment To LER 80-47/03L Beaver Valley Power Station Duquesne Light Company Docket No. 50-334 At 0935 hours0.0108 days <br />0.26 hours <br />0.00155 weeks <br />3.557675e-4 months <br /> on August 5, 1980, the No. 1 Diesel Generator circuit breaker failed to close, while operating the diesel in the " exercise" mode for the monthly surveillance test. At 1005 hours0.0116 days <br />0.279 hours <br />0.00166 weeks <br />3.824025e-4 months <br />, a second attempt was made to close the output breaker with the same results, no closure. Because it was not known at this time that this problem was only in the manual circuit, the setting of containment integrity wag commenced. At 1143 hours0.0132 days <br />0.318 hours <br />0.00189 weeks <br />4.349115e-4 months <br />, troubleshooting of the control circuit was completed. The trouble was traced to one contactor on the manual start relay. The bad contact was dirty and did not make a complete circuit when the relay actuated. The affected contact was used to latch in the " manual start relay".

The reason the circuit breaker would not close was that, when started manually, the diesel generator does not switch to its redundant start circuit; so, when no. contact was made, the breaker could not actuate.

The problem in no way affected the " auto" start feature of the diesel, which would have automatically started and loaded upon a loss of power. All surveillances were completed satisfactorily by 1322 hours0.0153 days <br />0.367 hours <br />0.00219 weeks <br />5.03021e-4 months <br />. Upon replacement of the contact block, the diesel was again started and loaded to check out the relay contacts.

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