ML20041B399

Updated LER 81-029/03L-0:on 811210,during Surveillance Test of Bus 16 Undervoltage Relays,Error in Disconnecting Test Equipment Resulted in Blown Fuse for A-phase Relays.Fuses Replaced & Normal Power Restored to Bus

ML20041B399
Person / Time
Site:	Prairie Island
Issue date:	02/12/1982
From:	Musolf D NORTHERN STATES POWER CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML20041B393	List: ML20041B392 ML20041B399 ML20041B404
References
LER-81-029-03L, LER-81-29-3L, NUDOCS 8202230605
Download: ML20041B399 (1)

Text

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UmTE REPORT ggggggEkON CONTROL OLOCK: l 1

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(PLEASE PRINT oR TYPE ALL REQUIRED INFORMATICN) lo it i MI NjP lI lN l 1l@l 010 l -l 0 l 0 l 0 l 0 l 0 l - l Q 0 l@l 25 4 l 1 l 1 l 1l 1l@l l lg 7 8 9 LICENSEE CCDE 14 15 LICENSE NuvaER 20 LICENSE TvPE JJ 5 7 GA T t,d CON'T IoIil S$RCE l Lj@l 0] 5 l 010 l 0 ] 2 ] 8 l 2 @l 1l 211 l 018 l 141 @l0 l 2 l 1 l 2 l 8l 2l@

? 8 60 61 COCKET NUMBER 68 69 EVENT D ATE 76 REPORT DATE tIQ EVENT DESCRIPTION AND PROSABLE CONSECUENCES h l o 121 l During routine surveillance test of Bus 16 undervoltage relays, an error in dis- l l___ connecting test equipment resulted in blowing fuse for A-phase relays. C-phase Iotal l

[o l4 l l fuse was removed as part of test procedure. The voltage restoration and load l io ;3; ; rejection. scheme initiated, and since UV condition continued to be senced, closed D2 l ggl diesal supply breaker. Diesel generator D-2 supplied bus until fuses l lTTf] l replaced and Bus 16 reenergized from its normal offsite source. No effect on l i o ,3 i i public health and safety. Bus 15, the redundant bus, remained fully operable. l 7 8 9 80 SYSTEM CAUSE CAUSE COMP. VALV E CODE Co0E SUSCCOE COMPONENT CODE SUSCODE SUBCODE lo!91 l ElB l@ l Dl@ l Z lh l Z l Z l Z l Z l Z l Z lh lZ l@ lZ l@

7 8 9 10 11 12 13 18 19 20

_ SEQUE NTI AL OCCURRENCE REPORT REV'SION EVENT YEA R REPORT NO. CODE TYPE NO

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,,,. 22 23 JP 28 2J 30 31 32 K AC N O PL/NT tET hours 22 58 IT FoR B. SUPPLI E MAN FACTURER lJJA !glJ4G lg lh7 lg, l36Zl@

l0l0l0l l lNlg 41 lNlg lZlg lZj9l9l9lg 3/ 40 42 43 44 47 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS h .

l i ) o i l Fuses were replaced and normal power restored to bus. The undervoltage relay tests, l

[ i l i j j for all four safeguard buses, will be revised to include two separate steps  ;

it i ; i l with signoffs when disconnecting test equipment. The existing procedure l l , ; ., i l uses a single step to disconnect test equipment at the bus cubicle and at the logic j iii,il relay cabinet. Two steps will make an error of this type less likely.  ;

7 8 9 80 ST S *f. POWE R oTHERSTATUS DIS V HY DISCOV4RY DESCRIPTION I1 l5 l l El@ l 1l 0 l 0 lgl NA l lBlgl Surveillance test l

ACTIVtTY CO TENT REtEAsEo op RELE-E mount LOCATION OF RELEASE @

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PERSONNEL EXPOSURES NuYM R DESCRIPTION t

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Di i"Id 3LE81 40 UA l ll ll llll l tit lj 66 69 do I 8202230605 820212 D M Musolf E PHONE:

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