ML20151C195

AO 24-75:in Jul 1975,design Analysis Not Done for Addition of Breaker & New Security Sys Load to safety-related 480 Volt Bus 2A.Caused by Administrative Control Failure.Circuit Design Analysis Requested to Justify Circuit Configuration

ML20151C195
Person / Time
Site:	Big Rock Point File:Consumers Energy icon.png
Issue date:	11/06/1975
From:	Sewell R CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.)
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
AO-24-75, NUDOCS 8103090364
Download: ML20151C195 (1)

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q t THIS IS TO FULFILL OUR VRITTEN CorYITVElli TO THE NRC CF AO 2$75 A S REPORTED TO YOUR YP. HUNIEP. BY D E DE P OOR AT 0930 NOVEf'BER 6, 1975.

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I PEPO?.T NO - A0 E4-75, DDCKET 50-155 m

EA REPORI DATE - NOVEt3ER 6, 1975 p..,

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E3 0'CCURRENCE DATE - ABOUT JULY 1975, CLASSIFIED A0 ON 11-6-75.

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3 FACILITY - BIG ROCK POINT PLANT 8

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4 IDE'iTIF IC A T IO N OF OCCURRENC_E,- IrPROPERLY AUTHORIZED ADDITICN 8

( CF LOAD TC ScFETY RELATED 4E0 VOLT BUS EA.

5 COCITIONS PRIOR TC OCCUERENCE - STEADY STATE FCVER CFER ATICN.  ;

^ d DESCRIPTION OF CCCURRENCE - DURI';2 REVIEV CF A PRO?CSEC ADDI-TIONAL LCAD ON BREAKEP SE-Et-63 CIRCUIT IN OCTOBER 1975, TFE CUES- ,

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• TION OF DESIGN ANALYSIS VA5 RAISED O!! THE ADDITION CF TFE SREAKER AND THE NEV SECURITY SYSTEP LOAD ON OR ABOUT JULY 1975 SUBSEQUENT i

• "' *T'/ I EV CN 11-6-75 REVEALED THAT NO DESIGN ANALYSIS HAD BEEN DONE.

O '7 DESIGNATION OF APPARENT CAUSE OF OCCURRENCE - FAILURE OF AD-PINISTR ATIVE CONTROLS.

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THIS DOCUMEHT C0nirins -

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' 8 ANALYSZS OF OCCUR NCE - PC3TULATED LOSS OF ' 2A BUS DUE TO

@ U NC00RD!NATED TRlPPIN3 CR EXCESSIVE LOAD .80VLD INC APACITETE SEVERAL

• REDUNDANT SAFETY RELATED PIECES OF' EQUIPVENT AND THE STA TION BATTERY r - C HAR GER . HOWEVER, A PRELIFINARY ANALYSIS ON 11-6-75 AT 0830 BASED ON ACTUAL CIRCUIT LOADS INDICATE 3' CON 3IDERABLE FARGIN FOR LOAD AND IS NOT OF CONCERN AT THIS TIFE. A TRIPPING CCORDINATICN STUDY IS NEEDED, HOWEVER.

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9 CORRECTIVE ACTION - A CIRCUIT DESIGN ANALYSIS HAS 3EEN RECUESTED U 5*'

WDF ENGINEERING SUPPORT GROUPS TO FULLY JUSTIFY THE EXISTING CIR-C UIT CONFIGURATION.

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10 FAILURE DATA - SIVILAR AND RELATED .TO A0 22-75 PER OUR LETTER OF SEPTEMBER 22, 1975.

O RALPH 9 SEUELL NUCLE AR ' LICENSING A DP CONSUFERS POWER CO -

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