ML20062C794

LER#78-089/03l-0 on 781022:severe Arcing Observed at Exciter Collector Ring of B31-S001A.A M.G. Set Tripped Before It Could Be Removed from Svc.Bolts Used to Fasten Brush Holders to Yoke Assembley Caused Brushes to Arc

ML20062C794
Person / Time
Site:	Hatch
Issue date:	11/02/1978
From:	Nix R GEORGIA POWER CO.
To:
Shared Package
ML20062C792	List: ML20062C794 PM-78-414, Forwards LER 78-089/031-0
References
LER-78-089-03L, LER-78-89-3L, NUDOCS 7811140162
Download: ML20062C794 (2)

Text

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, LICENSEE EVENT REPORT CoNinoL4 Lock: l l l l l l lh (PLLASE PRINT On TYPE alt. RLOulnED INFORMAllON) i o

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~8 l EVEfJT DF5CntPTIOfJ AND PRORACLE CONSEQUCNCES h idLJ l Durinq normal operation, severe arcino was observed at thn evciter enllectnr I

'o 13 i i ring of B31-So01 A. Before the "A" M. G. set could be rcmoved frcn service. it I o la I I tripped. The collector ring and brushes were found to be badly burned as a result I o Isi i of the arcing. The "A: M. G. set was repaired and placed back in service, in less _]

o 16 I I than the specified time for cold shutdown (Technical Specification 3.6.J.). Public I gtj l health and safety were not affected as a result of this incident. I O is i I I s9 so OE CO E $ 8C E CO*APONENT CODE SuecodE 5 E m L I Cl Bl@ [A_j@ l C l@ l GlE I til El Rl Al@ LD_j@ [Zj @

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33 l ash IO JG 31 40 di 43 44 41 CAUSE DESCRIPTION AND COPRECTIVE AC180NS h T[Tll The bolts used to fasten the brush holders to the yoke assemb1v, on two of the I iis j l brushes, were of sufficient length to force the brush tensioniro sprina into the 1 i i,i l area occupied by the brush. This caused the brushes to ARC as the brush ends were i

,i3i l worn away and the brushes could not slide in against the collector ring. Personnel l i il,_, had completed checking these brushes on the day of the incident and failed to (cont.)I

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NAME OF PREPAltEll3 E IIN PHONE: N N buperisiteridertl at Hairiteriaitce g

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. Georgia Power Conpany

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,  !** Baxley, Georgia 31513 I

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Reportable Occurrence flo. 50-321/1978-89

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j Cause Description (cont.) -

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recognize a problem. Personnel were reinstructed as to what to look for when checking brushes. The brush holder bolts, the brushes, and the collector ring were replaced and the "A" Recire. M. G. set was returned to service. .

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