PNO-IV-90-025, on 900716,Unit 1 Tripped from 100% Power During Operational Test of Reactor Trip Breaker Trip Actuating Device Which Forced Outage to Exceed 72 H.State of Tx Informed.No Press Release Issued

PNO-IV-90-025:on 900716,Unit 1 Tripped from 100% Power During Operational Test of Reactor Trip Breaker Trip Actuating Device Which Forced Outage to Exceed 72 H.State of Tx Informed.No Press Release Issued

ML20055G069
Person / Time
Site:	South Texas
Issue date:	07/17/1990
From:	William Jones NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
To:
References
PNO-IV-90-025, PNO-IV-90-25, NUDOCS 9007200108
Download: ML20055G069 (2)

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" July _17, 1990=

PRELIMINARYJNOTIFICATION'0F EVENT'OR UNUSUAL OCCURRENCE -- PNO-IV-90-25 .

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k " ITNis preliminary notification' constitutes EARL) notice of events of POSSIBLE ' 1 b

• V , safety oripublic; interest significance. The information is as initially received. i Lwithout verification or evaluation, and is basically'all that is known-by the '

4 ,  ; Region-IV staff.on-this date., j i

, . . L J' FACILITY: South Texas Project,l Unit 1- Licensee Emergency Classification:

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1. s Bay City; Texas- Notification of Unusual Event- <

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, , Docket _No. 50-498 Alert v

,i! l Site Area Emergency . ,

-l L General Emergency '

h X Not' Applicable ]

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SUBJECT:

n' FORCED OUTAGE TO EXCEED'72 HOURS 1 k On July l16,1990, at:2:36- a.m. (CDT) Sou't h-Texas Project. Unit 1, tripped. from-l 1

.100 percent power during an operational test of a reactor trip breaker trip , 2l

, actuating device. The urgent failure signal generated:by the test did not clear s

. when tthe multiplexer test switch was-taken from the test to normal position. The

! operator did not notice:that the local urgent failure signal light-was= still: lit '

prior to proceeding to the next train.. When-theLsecond multiplexer switch wast

-taken to test the-two-out-of-two; coincident urgenti Nilure signal logic was

, satisfied and the reactor trip breakers opened causing the reactor trip. All'  !

systems _ subsequently operated as. expected, l

, 1The licensee hasLdecided to maintain the unit shutdown while work activities are , 1 completed on the feedwater isolation valves, secondary steam leaks, main - ,

, generator voltage regulator, circulating water system, and the multiplexer! test 1 switches. ; Main generator breaker closure.is scheduled for July 20, 1990., l i

Neitner' the. licensee nor the:NRC plans :to issue a' press . release, i i c+ .. . . .. . .

e tThe state'of' Texas will be informed.  !

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Region IVireceived notification of this occurrence by the resident insp~ector--

ifromthe.licenseeat3:40p.m.(CDT). Region.IV: bas' informed EDO, NRR,~ and-PA.

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( iThis information has beenLeonfirmed with a licensee rspresentative '

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$ W. B. Jo'nes FTS 728-8137 47i m  % LCONTACT:

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1 INRC1718s EDOPN- Executive Director for Operations (Doris Day) . ' 1NRC1516EOGCPN General.Coun'sel (Dianna Papini)' . 4 INRC1718 GRIGGS Governmental & Public Affairs.-(Dianne Griggs) ' 1NRC1718L OCAPN GPA: Congressional-Affairs (JaniceHester) '1NRC02- OPAPN- GPA:PublicAffairs(GladysOrdaz) INRC0304 SLIPN- GPA: State / Local-Indian Tribes Program (Kath' Kerr) . Inspector _ General (Displaywriter/PC)- ^ NRCRMP OIGDW NRCRMP' IRMPN IRM--(Dick Hartfield) , INRC0304 NMSSPN-: Nuclear Material ' Safety & Safeguards (Pat Graaf) INRC0506 NMSSPN Nuclear Material' Safety & Safeguards (Cath INRC1112 :NRRPN-' Nuclear Reactor Regulation (Donna Berean) y Jenkins) i 'NRCRES. tRESPN Research(PatThompson)' NRCRI RIPN Region I  : NRCRII' RIIPN . ~ Region II NRCRIII RIIIPN Region III NRCRIV RIVPN Region IV NRCRV RVPN-  ; Region V 3 1 l l '* Does not include non-NRC locations (labs, utilities) l f -_ -__ _ ______________ _ ___. __ -