ML17252B482

LER 76-062-00 for Dresden, Units 2 and 3 Re Upon Completion of Routine Diesel Generator Surveillance Testing, Control Switch Was Placed in the Stop Position, Generator Output Subsequently Became Erratic, Generator Voltage Began Oscillating.

ML17252B482
Person / Time
Site:	Dresden
Issue date:	10/29/1976
From:	Stephenson B Commonwealth Edison Co
To:	James Keppler NRC/RGN-III
References
BBS LTR 76-757 LER 76-062-00
Download: ML17252B482 (3)

Text

..

Commonv.rah Edison Dresde.1 Nucle~ower Station

..... R.R. # *,

Morris, Illinois 60450 Telepho;ie 815/942-2920 BBS Ltr. 1176-757 October *29, 1976 Mr. James G.. Keppler, Regional Director Directorate of Reg'ulatory Operations - Region III U. S. Nuclear Regulatory Commission 799 :Roosevelt Road Glen Ellyn, Illinois 60137

REFERENCES:

Docket No. 50-237 Doc~et No. 50-249 Enclosed please find Reportable Occurrence report number 50-237/1976-62.

This report iS bein~ submitted to your off iCe in accordance with the Dresden Nuclear Po~er Station Technical Specifications, Section 6.6.B.

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L-i('~ B. B. Stephenson fr Station Superintendent Dresden Nuclear Power Station BBS:jo Enclosure cc: Director of Inspection &.Enforcement Director of Management* information & Program Control

• File/NRC

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LICENSEE EVENT REPDF9 CONrROL Bl:OCK: .....

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1 6 LICENSEE LICENSE EVENT NAME ucrnsr NUMBER TYPE TYPE

@E] IIILIDIRISl~I 10101-10101019101-10101 l-4ltlilllfl 10131 7 8 9 14 15 25 26 30 31 32 REPORT RE PC RT CATEGORY TYPE. SOURCE DOCKl;T NU.MOER EVENT DATE REPORT DATE

'@E]coNT I I. I lbJ U::J Io I s I o L- Io I2 I 3 17J 101q 13lo17ll. I I/ IOl;Ll~l?l&.1 7 ' B 57 58 59 60 . 61 68 69 74 75 80 EVENT DESCRIPTION

@Ifil I UPON CoMP}..E.TtDN OF RoUT1N£ UN1 T ').._h Dr ~S£k GEN£RA-fop___ SuRycr L.IJCINcf: I*

7 8 9 . . . 80 f

@faLJTEST1NG:, TH£ CONTROL.. S0v1TcH WA~ 'P).._P,CC:::D IN TH:G".STOP pos1T10N. .f 7 B 9 80 lo148 9I THC 6-ENERAToR 7 . . .

OUT PU/ SVBSE. QUE:NTLY B~Cfim£ ERR.41/C.. THE G-EIVE"RATOR-80 I

lol51 !VOLTAGE .BE.Gr-,f'J 7 .* 8 g* .

osc1 L/..:..AT/NG-, AND THE AC AND De CURRENT f'l'lCTE Rs 80 I

[Q]B] I WC.NT OF"F.;.SCAL£. TH£ uN1T-~ DIESEi- G-ENE.RAToR. WAS 1wir1£DfAT£J,,Y vc=~1F1E_D I 7 8 9 PR:ME (St:E' .'\ITAOISD Si-IEE.T) . 80 SYSTEM CAUSE COMPONENT COMPONENT ,

COOE CODE COMPONENT CCJOE SUPPUEn MANUFACTURER VIOLATION 7

@01£1£1 l[J 8 9 10 11 12 1£1.NIGlllNIEI 17 lAJ 43 44 IWI01lll71 47 w 48 CAUSE DESCRIPTION lolel .f-:n-4£ 1>1£$EJ_ Gi=.NERATOR.. Mf!J...FUNcn oN RESUt..IED [Rom A SHORTED SEJ....ENIVM

7. 8 9 . . . . . 80 lolsl !"i?f:CTIFIER. IN 1H£ GENER.ATOR. 1-1£&.D CIRCUIT, THE SHORT WflS. APPM~.ENT/.._y*

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• ,* 7* 8 9 FACILITY . . . . ... ~ET:l~D ~;* . . . **. *... . . (S£it f.JTAUlGi5"<;1~£'t:_'/)80 STATUS  % POWER OTHER STATUS DISCOVERY DISCOVERY DESCRIPTION EID 7 B 9

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I~ 12I 13 NA 44 U3J 45 J\11-l 4-6-----------:------'80 I

FORM OF .

ACTIVITY

• CONTENT RELEASED

• OF RELEASE AMOUNT OF ACTIVITY LOCATION OF RELEASE E.EI lZJ l.Zl IL--_ ___;._Ni..,;,_1-1_ ____.

44 Nil 7 8 9 10 11 PERSONNEL EXPOSURES NUMBER. . TYPE DESCRiPTION

~ jdlOIOI lKJ NA 7 9,9 11 12 . 13 80 PERSONNEL -INJURIES NUMBER DESCRIPTION

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7 . B 9 11 12 80 OFFSITE CONSEQUENCES

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7 8 9 80 LOSS OR DAMAGE TO FACILITY TYPE . DESCRIPTION 7~J a glZ.J 1~0_,_;..;_ NA_______ -'-------~-------------"-'-----'----------;:'::'.00 PUBLICITY 7

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/\/11 80 ADDITIONAL FACTORS E@ M 7 B 9 80

,)J EVENT DESCRIPTION (Continued) to be operable, as were the Unit-2 LPCI, core spray, and CCSW systems.. Since*

the Vnit-3 diesel generator was out of service at the time, all fuel movements were suspended on Unit-3, which was in a refueling_outage, The diesel generator was manually shut down, This is not a repetitive occurrence, (50~237/1976-62}

CA.USE DESPCRIPTION (Continued)

The rectifier failure evidently resulted in damage to, a* s~milar unit. in the circuit. Both were replaced, and the Unit 2/3 tliesei genera'tor ~a~ successfully tested and returned to service.

Modification requests. have been initiated. t.o replace the rect_ifiers on all three diesel generators with physically large'!- unfrs that have higher voltage ratings. Installation of these higher capacity units will provid~ a §atisfactdry long-terin corrective action.

• The rectifiers are model 300U80 selenium components manufactured by International Rectifier.