ML20071G085

/01T-0 on 781127:Diesel Generator 2 Failed to Auto Close Onto the Bus;Breaker Mode Switch Contracts27-27c Failed to Make Contact.Caused by Contact Failure

ML20071G085
Person / Time
Site:	Fort Calhoun
Issue date:	12/08/1978
From:	Core M, Gordon Peterson OMAHA PUBLIC POWER DISTRICT
To:
Shared Package
ML20071G084	List: ML20071G082 ML20071G085
References
LER-78-038-01T, LER-78-38-1T, NUDOCS 7812200267
Download: ML20071G085 (3)

Text

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REPORT DATE so EVENT DESCRIPTION AND PROBA8LE CONSEQUENCES h t o i:! l During preoperational testing of the new offsite power icver s rsten, Diesei Generste - t

,3 ; jNo. 2 failed to auto close onto the bus. 3reaker mode svitch contacts27-27C failed to I

c, , , ; ;nake contact. Reference Technical Specification Section 2.7. I io is! I l 10 is i i  !

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j, i o , J Centacts27-27C cn General Electric switch model vere not ==>dnt; centact. The vires I

, ,,,; vere =oved to spare contacts25-25C. The generator was successfully retested. No I f

L!'l.] I urther ac.lon is anticipated. i I ! 31 I i 84 II 7 8 9 E0 P 4C:uTv stETHCO OP STATUS  %'CWER CTHER STATUS DISCCVERY DISCOVERY OE3CRIP*:CN 3.

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• NAME Op onEPARER M. Core /G. Petersen PwCNE: ho2d26 holl {

!EP.78-038 C=aha Public Power District Fort Calhoun Station Unit No. 1 Docket No. 05000285 Attach =ent No. 1 Safety Analysis During testing of the newly installed 0?LS syste=, the failure of contacts27-27C en the auto close breaker =cde switch (h3-1/1AD2) was discovered. Had the nal-function not been discovered during this special test, it vould have been dis-covered during the surveillance testing of the engineered safeguards system per ST-ESF-6.

At the time of the failure, the plant was in a refueling shutdown condition. In addition to the redundant generator, DG-1, which was fully operational,161 and 3k5 K7 power was available frc= off-site. The failure could have occurred during power cperations, hence. the reason for immediate reporting. The failure was not annunciated since the alars is connected to different contacts of the switch.

The problem was cc:rected by moving the wires from contacts27-27C to spare con-tacts25-25C en the sa=e switch. This proble= is considered an isolated case.

Eevever, to insure the proble= does not occur in the future, positive verifica-tien of concact position and closure vill be made if possible on the six :.ede switches (breaker =cde switches h3-1/1AD1&2, breaker protection sede sh tches L3-3/1AD1&2, and diesel mode switches k3-1/D1&2) prior to eperation above 300 F.

Unless future failures dictate otherwise, no further action is anticipated.

Iza 78-038 -

Omaha Public Power District Fort Calhoun Station Unit No. 1 Dcchet No. 05000235 i

! Attachment No. 2 O

Failure Data-This is the first failure of a General Electric model switch at the Fort Calhoun '

Station Unit No. 1.

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