ML19224D803

LER 79-015/03L-0 on 790525:breaker 1AS Failed to Close Automatically.Caused by Improper Operation of Switch 52 in Breaker 1AN.Switch Contacts Cleaned & Tested Satisfactorily

ML19224D803
Person / Time
Site:	Cooper
Issue date:	06/23/1979
From:	Bednar L NEBRASKA PUBLIC POWER DISTRICT
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML19224D775	List: ML19224D774 ML19224D803
References
LER-79-015-03L, LER-79-15-3L, NUDOCS 7907170061
Download: ML19224D803 (1)

Text

NRC FORM 366 U. S. NUCLE AR REGULATORY COMMISSION t747)

LICENSEE EVENT REPORT CONTROL BLOCK: l l l l l (PLEASE PRINT OR TYPE ALL RECUIREf INFORMATION) 0 1! NIE lClPlRl1 14 l@l 'S 0 l 0 l - l 0 lLICEN0 I

!OAdERI- l0 0 l 0 l@!!. l1 25 26 l1 l1 !1 @le7 CAT LICENSE TY PE JO l

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3 3 LICENSEE CODE COWT ol1 [g"c' l L l@l 0 ] 5 0l0l0l2l9l8 dl0l512I517!9 hl016 68 69 EVENT DATE 74 75 1 I7 lo h REPCRT DATE dJ d 60 61 OOCKET NUMBER EVENT DESCRIPTION AND PROBABLE CONSEQUENCES h a 2 }Af ter reactor scrammed on APRM Hi upscale, breaker lAS f ailed to close automatically. I o 3 lThe breaker was then closed by its control switch. Breaker lAS ties 4160V bus lA to l 0 4 lthe startup transformer when the generator trips. Breaker 1FA failed to trip automatic-1 o s I lly and when its control switch was operated to TRIP. This breaker is one of two bre- l 0 6 pkers connected in series which ties 4160V bus IF to bus lA. This occurrence presented I oI7 Po adverse consequences to public health anci safety. Redundant systems were available. l o 3 prwher IFA failure to trip is repetitive (79-8). _ l SO 7 8 9 SYSTEM CAUSE CAUSE COYP VALVE CCOE CODE SUSCOCE COMPONE NT CODE SU8COCE SUBCODE 7

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9 10 11 12 13 Cl Ki Tl Bl Rl Klh l El@ W @ 18 19 20 SEQU E N TI AL OCCUR AENCE REPORT REVISION EVENT YE AR REPORT NO. CCOE TYPE NO.

LER AO h AEPORT 7l 9l l_ 0 1l 5l l/l l0l3l lL l l-l 0l 21 22 23 24 i6 27 23 29 30 31 32 ACTION FUTUAE EFFECT SHUTOCWN ATT A CH M E N T N P R O.4 PRIME COvp. COMPONENT TAKEN ACTICN CN PLANT VETHOD HOURS SU8vlTTED FORMdUB SU PP LI E R MANUFACTURER l F lg F l@ lh Z lg lZl@ 0l 0l 0l l l Nj@

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33 34 36 31 40 42 43 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS 1 oil Breaker lAS apparentiv failed to close because of imoroner coeration of switch 52 in I i i breaker lAN. GE has been recuested to evaluate. Switch contacts were "1n,-ad ,,a *ns*al

, ,, l satisfactorily. breaker 1FA faC ed to trip because switch 52H failed to close. A 3/4" I i 3 l bushing was placed on the operating bolt to ove. . ride linkage clearance and force con- J 3 2 ; l tact closure. Breakers are GE Magna Blast Tvoe AMH 4.76-230. I 7 3 9 30 ST S  % PCWER OTHER STA TU3 ISCO R OISCOV ERY DESCRmTION 1 5 lClh l0l0l0l@l NA l l A l@l Operator Observation l A Tiv TY CONTENT AELEASED OF AELE ASE AVOUNT OF ACTIVITY LOC ATION OF AELEASE 6 NA l NA l 7

1 4 3 Z l @ 10l Zl@l 11 44 45 30 PE ASCNNEL E xPOSLRES NUMRER TYPE D E SC PI PTIC N 7

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PE%CNNEL .NA RIES NUv3tA OESCRiPTION

, 4 i 3 0l0l0l@l 11 12 NA 80 LOSS OF OR D AM AG E TO F ACILITY PE CESCRIP'lON 7907170C(m' O 7

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