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1 Tof Jnr.cs P. O'Rollly.
pirvctorate of negolatory Operations Region 1.
631 Park Avenue,.
King of Prussla,..PeAnsylvania a 19406.
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From:
Jersey Centrsi:. Power $ Ligit; Company:
Oystcr. Crcok Nuc1 car Generating Station. Docket 750 4 19 '
- ForkedaRiver,.New ' Jersey.' 08731 -
subject:
Prelirdnary-Abnormal.0ccurrence.Roport No. 73 ' 1 i
The following i's a preliminary. report.being submitted -
in compliance with the..Tc.chnical Specifications,-
paragraph.6.6.2.
Prclininary Approva):-
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12/14/73~
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Abnorcal occurrence..
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, Report No. 73-31: -
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Honentary ihteruption -of '12SV :DC power supplying" instrumentation ~
associated with varloas. safeguard systems,-
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' This eventcis considered to-beinn abnormal' occurrence as : defined in the Technical Specifications,: paragraphs <1.15n 'and fi. J Natifi -
cation.cf.this event, 4 required' hy the Technical Specificitions, paragra3 s' 6.6.2.a, vasemade to tho AEC, Region 11,. Directorate of -
d Regulatory Operations, by--telephone.on Friday,: December 14p 1975,'.
at.1610, and bP telecopicr: at 17b0..
SITUATIONg An electrical Around.had developed.on.125V DC ' distribution;' bus "A"MreAulting in-electricians 'beingecalled in at,approximately 13,19' 3.to troubleshoot and < repair this problem.<
7 2500, Decerbc Electrical grotmds of thi[.naturt. hove been an : infrequent problem, in.the past :and' 4.of this.. tis no. approved procedures have been developod.
It is cauaon knowledge that any clutemption' of ' power
- te power panel "ti".results,I.jn :sdvorse cffects regarding service to safeguard instrumentation. Consequently,.the electrician, who had perforced this sse maintenanco activity of troubicshootinr.
and re aircon occasion in.tho past,,'.. proceeded to place a jumper-in a position that would : parallel' the "A""and "B" ' distribution busos. Ris, then, provided non-interuptible-siternate feed to power.panet."E" ar,d by ' actuating the " break before make" throwover.
switch, it could be determined if the ground was in tho "E" e
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t j 4 Abnormal occurrence Report Ao;. 73y31....
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- J '. '< ' Dei.erber-13;' 1973.'
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power panet by observing the indicating lights..on the "B" bun llowever, the electrician.placed the.jusper in the wrong position.
and' effectively <did not have :the -huser.* paralleled as desired.-
Upon pushing the local b'utton for transferring.ths."E" power.
- pancI.from the "#f"to thed!B" bias, there was a. momentary inter -
uption of power on $the ordar of silliseconds, caused by the' <
normal. action of tho." break hefore. mike" avitchj with}the fol.
I lowing results:-
3 1.
Operating.CPd) pump)"A""trippod.'due to loss of power to Iow i
pump.; suction trip" circuit; operator ir.nediatelymstarted..
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- 2..."B" isolation condonsor isolated due to : loss. of power to '
pipe-break. monitoring system. Oparator irnodistely reset isolation condenser isolation button and valving rc-niigned -
proporly.for nor:tal standby < service....
3, Clean'-up systein isolated due to loss of power to relaying -
associated:vith.this function r Operator returned system :to.
service as por norical: proceddre.
4 DC power was. lost,to clogic channel C (Core Spray System.I)
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andelogic chonnel:D-(Core Spray Syston II)for.the brief intervali- 'I1tese channels icacdiately reset autoe.atica11y.
requiring no operator. action.- Logic channels "A" and "B" were not effected and the redundant equipment in esch system was availabic. c.
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.. De' ter 13,1973 Roport No. 73 31
- 5..r.DC po.wer was lost. to.the logic channels of Containment Spray System I.
Again, with.the rapid restorat' ion 'of power, the logic was autoratically restored. 'Ihe. redundant system 11 was not offected and would have operated if necessary.
No operator action required',-
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6 A trotblo ' alarm was received on both diesel generston, but was 1ccediately roset from the control'roon and was strictly due :to loss of DC power to the alarm relay and had no offect on. automatic' operation of.tho' diesel generators.
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LosthDC power to nain steam lsolaIlon valvesy but had no effect on valvo operation since ' AC power.was still available and.pormitted valves to stay open..
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- 8.. DC power was lost. to misec11pncous. annunciators and panels, tut did not have any additional effect in the ' safe bperation of the plant.
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PEHEDIAL ACTION:
Restoration of the equipment.to nomal status was accomplished through the'sutordtic reset : function of offe~cted instru:entntion.
As noted above, the isolation condonsor, CRD ptmp, clehn-up systen and miscellancout. 31 arts functions were manually ' reset and restored to normal service inmediately.
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SAFl?rY SIGNIF1 0.NCE!
As the. interval"of. time. involved in this incident.'is.on the :i-order' of milliseconds and all:effect.ed systens.resot '.inacdiately or within several! seconds where operator action.was required,-
the safety..significanco.cf this cVent-1.i minimal'., In 'the case of tho : isolation. condenser, design < redundancy was.. lost..for~ the.
interval prior.to the operator. resetting.theisystem.- flowever,c-3 the.Tedundant. isolation condenser was available and:would,have 1
perforced.if roquired..
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12/14/73*
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