PNO-IV-90-030, on 900910,licensee Declared Unusual Event W/ Reactor at 100% Thermal Power & Reactor Shut Down.Also on 900909,inverter Declared Out of Svc Following Unexpected Trip.No Cause Found.Troubleshooting Continuing

PNO-IV-90-030:on 900910,licensee Declared Unusual Event W/ Reactor at 100% Thermal Power & Reactor Shut Down.Also on 900909,inverter Declared Out of Svc Following Unexpected Trip.No Cause Found.Troubleshooting Continuing

ML20059K146
Person / Time
Site:	South Texas
Issue date:	09/10/1990
From:	Weibe J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
To:
References
PNO-IV-90-030, PNO-IV-90-30, NUDOCS 9009210174
Download: ML20059K146 (2)

• l

'S:ptemb3r 10,,3999 PRELIMINARY NOTIFICATION'GF EVENT OR UNUSUAL OCCURRENCE - .PNO-IV-90-30

' This preliminary notification constitutes EARLY notice of ' events of POSSIBLE .

safety or public interest significance. The information is as initially received, without verification or evaluation, and is basically all' that is known by the Region IV staff'on this date.

FACILITY:-Houston Lighting & Power Licensee Emergency Classification:

South Texas Project, Unit 1 X Notification of: Unusual Event -

Say City, Texas Alert DN: 50-498 Site Area Emergency General Emergency 4 Not Applicable'

~

SUBJECT:

REACTOR SHUTDOWN REQUIRED BY THE TECHNICAL SPECIFICATIONS The licensee declared a notice of unusual event (NOVE) at 8:22 a.m. (CDT)'.on

-September 10, 1990, with the reactor at 100 percent thermal power. This was required by the licensee's emergency implementing procedure for a reactor shutdown required by the Technical Specifications (TS). The-applicable TS, i 3.8.3.1(g), requires that the 120-volt AC vital- Distribution Panel DP002 be energized from its associated inverter connected to the safety-related power supply. The TS allows the distribution' panel to be connected to a nonsafety-related power supply for up to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> or, otherwise, be in hot 3 shutdown within the following 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />. 1 The inverter was delcared out of service on 8:22 a.m. on September 9,1990,i 1 following an unexpected trip of the inverter. The "C train inverter trip.

resulted in engineered safety. feature actuations' of the control. room and containment building ventilation systems. The licensee powered'the inverter '

from the nonsafety-related power. supply and restored the ventilation systems to their normal lineups. The licensee's troubleshooting activities did not ,

identify the cause for the inverter' trip prior to exceeding the 24-hour TS limit for. continued operation.- The licensee expects to be in hot shutdown by  ;

1:22 p.m. -

{ The affected inverter is an'Elgor.25 Kva inverter which the licensee is-continuing to troubleshoot.

l Neither the licensee nor the NRC plans to issue a press release.

[

L

.The state of Texas will. be informed..

I Region IV received notification of this occurrence by telephone from. SRI at 7:22 a.m. Region IV has informed the EDO, NRR, and PA.

l This information has been confirmed with a licensee representative.

! CONTACT: J. Wiebe, FTS 728-8287

][Qdb F RM:D:DRP RA JCollins;df RDM in 9/10/90 9/u /90 n O s, v ,, ,s g

. ogt h

g92g7490091o .

PNO-IV-90-030 PNU

a

• g y ~

l DISTRIBUTION: . --

OWFN NMBB.  : NL' MAIL:-DCS(Orig.IE34)

Chmn. Carr CA NM55 HOF l!TS- DOT (Transp._Only)' l Com. Rogers OGCL 1 NRR' IRMc -

Com.- Curtiss GPA - SLITP- OIG' FAX:- (5520: /0/90 0 ///M ' l 1

Comm. Remick PA' OE TWO egT6ns & HQ)_'

2 ,ACRS EDO' PDRL . 1

. L-St NSAC1+

W RRI- >

-t 1

EW-W NRC.0PS CtrJ ECAP Licensee:(Reactor)' ,

DISTRIBUTION:

Node Local 1, Name Address- NRC Office Receiving PN 't

.AE0D/PDR (Patty Wilson)

NRCRM AE0DPN .

NRCRH ROABPN ~AE0D -

NRCRMP ASLAPDW riter/PC) 1NRC1718 CARRPN ASLAP(Displayw(ConnieSchum)

Chairman Carr .

INRC1718 CURTISPN Comissioner Curtiss (Gigi Rammling)  ;

1NRC0708 OEPN Enforcement (Betty Sumers)  !

1NRC1718 ED0PN- Executive Director for Operations (Doris Day)-  ;

1NRC1516 OGCPN General Counsel-(Dianna Papini).

INRC1718 GRIGGS Governmental & Public Affairs (Dianne Griggs)-

INRC1718~ OCAPN GPA: Congressional Affairs (Janice Hester)

INRCO2 OPAPN GPA:Public Affairs (Gladys Ordaz)-

~1NRC0304 SLIPN GPA: State / Local Indian Tribes Program (Kath Kerr)

NRCRMP- OIGDW Inspector General (Displaywriter/PC) 4 NRCRMP IRMPN IRM (Dick Hartfield)- .

i 1NRC0304 NMSSPN Nuclear Material . Safety & Safeguards (Pat Graaf) '

1NRC0506 NMSSPN Nuclear Material Safety &' Safeguards (Cathy 'Jenkins)'

1NRC1112 .NRRPN NuclearReactorRegulation(DonnaBerean); e 1 NRCRES RESPN - Research'(Pat. Thompson) 4 NRCRI RIPN Region I a NRCRII RIIPN Region II NRCRIII RIIIPN Region III  ;

NRCRIV RIVPN Region IV NRCRV RVPN: Region V

• Does not include non-NRC locations' (labs, utilities)- ,

i t

R l

-1 l

o l

,I

_ ,,