ML20042F194

LER 89-025-01:on 891101,sys Auxiliary Transformer Feed to Bus 142Y Tripped Open When Door Containing Undervoltage Relays Closed.Caused by Misalignment of Door.Door Repaired. W/900430 Ltr

ML20042F194
Person / Time
Site:	LaSalle
Issue date:	04/30/1990
From:	Bukantis L, Diederich G COMMONWEALTH EDISON CO.
To:	Office of Nuclear Reactor Regulation
References
LER-89-025, LER-89-25, NUDOCS 9005070366
Download: ML20042F194 (4)

Text

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) Commonwealth LaSalle County Nuclear Station Rural Route #1, Box 220 ECoon j

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.* v Marseilles, Illinois 61341 '

i \ Telephone 815/357-6761 ,

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April 30, 1990  !

Director of Nucisar Reactor Regulation U.S. Nuclear Regulatory Commission Mail Station P1-137 ,

Washington, D.C. 20555

Dear Sir:

Licensee Event Report #89-025-01, Docket #050-373 is being s submitted to your office to superceed previously submitted report #89-025-00.

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0. J. Diederic Station Manager LaSalle County Station GJD/ LAB /kg Enclosure h xc: Nuclear Licensing Administrator  !

NRC Resident Inspector NRC Region III Administrator INPO ~ Records Center l

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1 9000070366 900430 k DR ADOCK0500!{3 '\L i l

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LICENSEE EVENT REPORT (LER) 24 Facility N me (1) Docket Number (2) Pane (3)

LaSalle County Station Unit 1 015101010131713 1 of!0 3 Title (4)

Loss of Bus 142Y Ovo to Closine Switchaear Door and Jarrine Relays Event Date (5) LER Weeer (61 Recort Date (7) Other Facilities involved (e)

Month Day Year Year /// Sequential // Revision Month Day Year Facility Names Docket thseer(s) ffj/

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/ Number LaSalle Unit 2 01 51 01 01 01 31 71 4 11 1 01 1 el 9 el 9

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01215 01 1 014 31 0 91 0 01 51 01 01 01 1 I  !

TH15 REPORT 15 $UBMlliED PURSUANT TO THE REQUIREMEN15 0F 10CFR OPE"AU"C' (C'ieck one or more of the followine) (11)

M00E N 20.405(c) 50.73(a)(2)(lv) 73.71(b) 5 20.402(b) _ _KL _

POWER _,

20,405(a)(1)(l) ,__ 50.36(c)(1) , , , 50.73(a)(2)(v) ,, 13.11(c)

LEVEL 20.405(a)(1)(11) 50.36(c)(2) 50.73(a)(2)(vil) _

Other (Specify 0l 0l 0 (10) _ 20.405(a)(1)(lin) ,,__ 50.D(a)(2)O) __,,, 50.73(a)(2)(vill)(A) In Abstract 20 *5t*H DH') * "(an2nu) w.D(an2nvains) beiow and in -

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, LICENSEE CONTACT FOR THIS LER (12)

Name _,

TELEPHONE NUISER AREA CODE LarryBukantis.TechnicalStaff(olneer. extension 2701 8 l 1 15 31 51 71 -l 61 71 61 1 CO*LETE (meE LlWE FOR EACH COMPOWEN FAltuRE DESCRIBED IN TH15 REPORT (13)

CAUSE SYSTEM COMPOWENT MANUFAC- REPOR1ABLE CAUSE SYSTEM COMPONENT MRNUFAC- REPORTABLE TURER TO WPRDS TURER TO NPOWS  !

K El A l l l l l l N I I l l l l l 1 I I I I I I , I I I I I I I SUPPLf pENTAL REPORT EXPECTED (14) Espected Month l Day l Year Submission

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I lyes (if ves, complete EXPECTED SUBMISSION DATE) YlNO l ll ll ABSTRACT (Limit to 1400 spaces, i.e, approximately fifteen single-space typewritten lines) (16)

At 1706 hours0.0197 days <br />0.474 hours <br />0.00282 weeks <br />6.49133e-4 months <br /> on Novenber 1,1999, with Unit i defueled and Unit 2 in Operational condition 1 (Run) at 1005 power, the System Auxillary Transformer feed to bus 142Y was tripped open when an Equipment Operator closed the door containing the Bus 142Y undervoltage relays, neutral overcurrent relays, and degraded voltage relays. The door was misaligned causing difficulty la closing the door. Loss of Bus 142Y caused Reactor Building Ventilation (VR) Isolations on both Unit i and Unit 2. Unit 2's Standby Gu Treatment (5BGT) auto started. Unit 1 50GT did not auto start because its power supply was lost (142Y). 58GT W)de Rtnge Gas Monitor (WRGM) power was also lost, so Chemistry Service Department was notifled to pull smples (lodine and particulate). This event did not initiate a fast transfer to livs 142X, via the cross-tie breaker (not a safety function), nor did the Olesel Generator (OG) 1A automatically start. (DG 1A was out-of-service for maintenance.) At 1745 hours0.0202 days <br />0.485 hours <br />0.00289 weeks <br />6.639725e-4 months <br /> on November 1, 1989, the bus was energized and Bus 142Y was returned to service.

The auto transfer circuit will be tested. The relays sounted on Bus 142Y cubical door 2 will also be tested toseeifatripsignalcanbereproducedby,)arringthecubicaldoorandthecubicaldoorwillberepaired.

This event is reportable pursuant to the requirements of 10CFR50.D(a)(2)(lv) due to the actuation of an Engineered Safety feature System.

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• O tlCEN$EE EVEWT REPORT (LER) TEHT CWilbuAllGN Form Rev 2.0 FACllliY NAME (1) DOCKli NueER (2) ,,,,Lt3,,,WLseER (6) Pane (3)

Year

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LaSalle County Station 19 4 1 _ . O I $ 1 0 1 0 1 0 1 31 71 3 8l9 - 0l2l$ - 0l 1 01 2 0F 01 3 l TEXT Energy Industry identification System (Ells) codes are identified in the test as [XX)

PLANT AND $YSTEM IDEWilFICA110N General Electric - Dolling Water Reactor thergyIndustryIdentificationSystem(Ells)codesareidentifiedinthetextas[XX).

A. CON 0lil0N PRIOR TO EVLWT '

Unit (s): 1/2 twent Date: 11/01/09 Event ilme 1707 Hours ,

Reactor Mode (s): Defueled/1 Mode (s) Name: Defueled/Run Power Level (s): OF1005

8. DESCRIPil0N OF EVENT On November 1, 1999 at 1706 hours0.0197 days <br />0.474 hours <br />0.00282 weeks <br />6.49133e-4 months <br /> with Unit I defueled and Unit 2 in Operational Condition 1 (Run) at 1005 power, an Equipment Operator (EC) after removing an out of service, attempted to close a door on Switchgear ($WDR) 142Y (AP) [LA) Cubicle 2 and found that the door was cocked. This caused this door to contacttheadjacentdooratthetopwhichpreventedthedoorfromclosing. While the E0 was attempting to insert the doors closing bolt, he heard the noise of breaker (ACB) 1422 (System Aunlitary Transformer feed to Bus 142V) tripping.

There was no indication that the 142X/142Y cross-tie breaker, Ac8 1425, attempted to close to fast 1 transfer to tus 142X as designed. This resulted in the loss of 400 voit Busses 134X,134Y,136X and  !

associated Motor Control Centers (MCC's), as well as Bus 142Y.

Loss of Bus 142Y caused a Reactor Bullding Ventilation (VR) [YA) isolation on Unit I and 2 due to a loss ofReactorProtectionSystem(RPS)[VC)BusB. Unit 2 Standby Gas Treatment (StGT) [9H) auto started, however, Unit 1 StGT did not start because the AC power supply which powers its equipment was lost.

$8G1 Wide Range Gas Monitor (WROM) power was also lost, so the Chemistry Services Department was notified to take appropriate samples.

Olesel Generator (DC) (EK) 1A was out of service for the insta11ation of a modlMation and maintenance at the time of the loss of tus 142Y and therefore the diesel did not start.

This event is reportable pursuant to the requirements of 10CFR50.73(a)(2)(lv) due to the actuation of an Engineered Safety feature System.

C. APPARENT CAUSE OF EVENT The apparent cause of the loss of Bus 142Y was due to misalignment of the door on the auxillary compartment of $WGR 142Y, cubicle 2. ihls alsalignment made the door difficult to close, in the <

processofclosingthedoortheBus142Yprotectiverelaysmountedonthisdoormayhavebeenjarred .

causing one or more of the contacts to momentarily close. I

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- LLC 5EEE EVENT REPORT (LER) TERT CONTIMuAf tou Fom Rev 2.0.

LER MU SER (6) Pose Cl)  ;

FACI.LiiY'eM (1) DOCKET MUSER (2)

Year /// Sequential /// Revision l ffj/

// Numer fff

/// uweer ,

u5atte County $tation unit 1 0 1 5 1 0 1 0 1 0 1 31 71 3 819 - 01215 - 01 1 01 3 0F 01 3 l TEX) Energy industry identification System (Ell 5) codes are identified in the text as (XX)

O. SAFETY ANALYSl5 0F EVENT The t>us was not required to be operable for Unit I at this time because Unit I was defueled. At the time of the event, Unit 2 was in a timeclock for the 1A 00 Olvision 2 outage. The loss of power did effect common equipment required for Unit 2 operation. Power to the equipment that was lost was quickly restored (within I hour), if this event would have happened while Unit I was in operation, the fast transfer to tus 142X may have occurred (however this is not a safety function) or DG 1A would have auto started and picked up any of the tus 142Y essential loads.

E. CORRECTIVE AC110W5 At 1720 hours0.0199 days <br />0.478 hours <br />0.00284 weeks <br />6.5446e-4 months <br /> the isolations were reset and VR was restarted on Unit 2 once *B" Reactor Protection  ;

System (RPS)[YC]wastransferredtoanalternatepowersource. .The "t* Control Room and Auxillary l Electric Equipment Room Ventilation (VC/YE) [Vl] was started at 1720 hours0.0199 days <br />0.478 hours <br />0.00284 weeks <br />6.5446e-4 months <br /> to ensure it operated properly because the loss of tus 142Y caused 'A' VC/VE to de-energire.

At 1745 hours0.0202 days <br />0.485 hours <br />0.00289 weeks <br />6.639725e-4 months <br /> bus 142Y was energized and the 58GT WROM was restarted. At 1750 hours0.0203 days <br />0.486 hours <br />0.00289 weeks <br />6.65875e-4 months <br /> *A" VC/vt was restarted.

Unit 2 50GT was left running for approximately 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> so that the Chemistry Service Department could 4 take lodine and particulate sag les.

Bus 142Y auto transfer circuit logic was tested to verify proper auto transfer operation (in particular the Bus 142Y/X cross-tle breaker, ACB I425, auto closing circult). Bus 142Y protective relays were also be tested to see if any of the relays produce a trip signa) when they are jarred. This test verifled the proper line up of the bus 142Y-142X cross-tle breaker auto close log)c (ACB 1425). This test also closed and opeSed the faulty switchgear door several times, while monitoring several verlous relays that I

couldhavepresentedatripsignaltoAC81422Ifjarred. No visual actuation of any relays was observed nor did the chart recorders show any actuation of any of the monitored relays.

On Decoder 21, 1989, the cubicle door was repaired by recessing the door mounting holes per Work f;'

I Request L94322. The station will Install warning placards on switchgear undervoltage relay cubicle I doors to remind those who operate the doors of the potential for inadvertent actuations. Action Item Record (AIR) 373-356-90-10101 will track the completion of the placard installation.

l F. PREVIOUS EVENT 5 LER Numer 11tle L 374/87-012-00 Bus 243 4.16KV Feedbreaker Auto irlp Due to Failure of Degraded Voltage Relay Access Door Latch G. COMPOWENT FAILURE DATA None.

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