PNO-III-87-137, on 871027,reactor Srammed & ECCS Actuation Occurred Due to Deenergized Bus L12.Caused by Operator Mistakenly Tripping Supply Breaker from Transformer to Bus. Power Restored

PNO-III-87-137:on 871027,reactor Srammed & ECCS Actuation Occurred Due to Deenergized Bus L12.Caused by Operator Mistakenly Tripping Supply Breaker from Transformer to Bus. Power Restored

ML20236G053
Person / Time
Site:	Perry
Issue date:	10/27/1987
From:	Forney W, Knop R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
To:
References
PNO-III-87-137, NUDOCS 8711020393
Download: ML20236G053 (2)

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bm2 4 PRE _LIMifARY NOTIFICATf0N 0F: EVENT OR UNUSUAL'0CCURRENCE--PN0-ITI-87-137 Date October 27e '1987.

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,- This" preliminary notification constitutes EARLY notice of events of POSSIBLE safety f-

.or public interest significance. Th'e information is as initially received without '

verification or evaluation, and_is basically all:that is known by the Region III L. staff on this date.

Facility: Cleveland Electric Illuminating. Licensee Emergency Classification:

Company X Notification of an Unusual Event LPerry . -

Alert Perry, OH 44081. Site Area Emergency General Emergency Docket No. 50-440 Not Applicable

Subject:

PERSONNELERROR_(RESULTINGINSCRAM)ANDECCSACTUATION

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-At'6:38 a.m. (EST), October 27,c1987, with the unit operating at 45% power, operators tripped

- the supply breaker from the startup transformer to Bus L12 resulting in deenergizing Bus L12.

Prior to the event the operators were transferring house loads from.the Startup Transformer 1 (SUT) to the Unit Auxiliary Transformer (UAT). The operators closed the supply breaker -j from the UAT.to Bus L11 and the supply breakers from the SUT to Bus Lil opened as designed. '

At this.. point, the operator intended to place the control switch for the supply breaker from the'SVTito Bus L11 in the " trip" position to establish agreement between the switch and breaker.

The operator then mistakenly tripped the supply breaker from the SVT to Bus L12,

'deenergizing Bus L12. Power was restored to Bus L12 in about 4 seconds.

Deenergizing Bus L12 resulted in a low Hot Surge Tank Water Level Signal, loss of the

' operating Feedwater Pump, a' decrease in the Reactor Water Level, a Reactor Scram and initiation of the High Pressure Co.re Spray (HPCS) and Reactor Core Isolation Cooling (RCIC).

Reactor Water level decreased to approximately'120. inches (referenced to the . top of the active fuel) and was: restored _by HPCS and RCIC to within normal limits within three minutes following the scram.

'All systems functioned as designed and the licensee declared an unusual Event at.6:53 a'.m.  !

.(EST)dueto.theinitiationofHPCSandRCIC. ,

~With the Unit stable in the shutdown mode and all emergency plan notifications completed, the licensee terminated the Unusual Event at 7:30 a.m. (CST). l i

. DISTRIBUTION: l H' St.

. EDO NRR E/W Willste Mail: ADM:DMB  !

Chairman Zech PA IE NMSS D0T:Trans only Comm. Roberts ELD OIA RES  !

Comm. Bernthal AE0D NRC Ops Ctr ):58 ,

Comm. Carr' i

.Comm.' Rogers LACRS- SP c2,h Regional Offices

SECY CA INP03.M NSAC 3 9

. 'PDR RIII R'esident Office Licensee: J.' 67p (Corp. Office - Reactor Lic. Only) -

%393871027 0I O-Iy I-87-j a7 PDR Region III w wm m &j

3PREt.IM[ NARY NOTIFICATION 0F; EVENT OR UNUSUAL.. OCCURRENCE--PNO-III-87-137'Da'te' October 27,-1987l fT'hle" Senior Resident In'spector'arri_ved on the s'ite about 7:25 a'.m. (EST), is ' reviewing plant istatusand :the licensee's course of actior., and wi11' observe. scram recovery operations.

-The[ State'off0hiowillbenotified.

ERegion.III(Chicago)firstlearnedofthiseventat'7'a.m.'(CST), October 27, 1987. This (information~is current as.~of 10 a.m. (CST), October 27, 1987.

' $k

_CONTACT: ' R. - Knop..

W. Forney FTS 388-5547 FTS 388-5590 1

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