ML19257A935

LER 79-073/03L-0:on 791204,after Completing Weekly Testing on Diesel Generator,Associated Sequence Initiate Alarm Did Not Clear.Caused by Binding Auxiliary Switch Which Would Not Return to Open Position.Switch Replaced

ML19257A935
Person / Time
Site:	Calvert Cliffs
Issue date:	01/04/1980
From:	Bauer E, Lagiewski J BALTIMORE GAS & ELECTRIC CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML19257A932	List: ML19257A931 ML19257A935
References
LER-79-073-03L, LER-79-73-3L, NUDOCS 8001090429
Download: ML19257A935 (2)

Text

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10 l 3 l l observed that the associated " sequence initiate" alann did not clear. At l 0 4 1 1323, the 0.G. was removed from service to investigate the problem and l 0 s [ effect repairs on the output breaker. The breaker auxiliary switch was l l0 l6 l l found to be binding and would not return to the open position. l 0 7 l l 0 I a l 90 g g DE CO E SL8C E CO'.tPCNENT CODE SLac C'E S I DE O 9 S lH l@ [_EJ@ W@ l C l K ] T l B l R l K l@ y@ l Zl @

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41 W@ lAl@ lGl0 8 Olg 42 43 44 47 CAUSE DESCRIPTION AND COPRECTIVE ACTIONS i o i The faulty switch was replaced. O'odel dSBM Type 10 AX 01263). The procer I li li l I oneration of this switch can be observed durina the weekly functional test i li i 21 l of the Diesel Generators. Additionally, the breaker and its auxiliary j i 3 l ' switches are periodically inspected under the preventive maintenance l

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LER NO. 79-73/3L DOCKET NO. 317 EVENT DATE 12/4/79 REPORT DATE 1/4/80 ATTACHMENT

- - CAUSE DESCRIPTION AND CORRECTIVE ACTION: (CONTINUED)

Since the switch remained closed, the associated sequencer logic was continually energized and would not have functioned in the assigned time period (no delay would have occurred). However, a redundant sequencer and associated ESFAS equipment remained operable throughout the event.

While the 0.G. was inoperative, the remaining A.C. power sources were checked in accordance with Technical Specification 3.8.1.1. #11 Diesel Generator was returned to service at 1510. This is not a repetitive occurrence.

CAUSE DESCRIPTION AND CORRECTIVE ACTION: (CONTINUED)

Therefore, no further action to prevent recurrence is considered necessary at this time.

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