PNO-IV-90-034, on 900929,Unit 1 Manually Tripped & Will Remain Shutdown to Allow Repairs to Bellows in Low Pressure Turbine.Unit 2 Entered First Refueling Outage

PNO-IV-90-034:on 900929,Unit 1 Manually Tripped & Will Remain Shutdown to Allow Repairs to Bellows in Low Pressure Turbine.Unit 2 Entered First Refueling Outage

ML20059N353
Person / Time
Site:	South Texas
Issue date:	10/01/1990
From:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
To:
References
PNO-IV-90-034, PNO-IV-90-34, NUDOCS 9010120052
Download: ML20059N353 (2)

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October 1, 1990

' PREL'IMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE -- PNO-IV-90-34 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.

i FACILITY: Houston Lighting & Power Company Licensee Emergency Classification:

South Texas Project, Units 1 and 2 Notification of Unusual Event (Dockets: 50-498;50-499)

Alert i

~

Site Area Emergency i

General Emergency i

T~ Not Applicable

SUBJECT:

UNIT 1 FORCED SHUTDOWN TO EXCEED 72 HOURS AND UNIT 2 BEGINS FIRST REFUELING OUTAGE On September 29,1990, at 2:30 a.m., Unit 1 was manually tripped from 100 percent power. A partial stroke test of the "A" feedwater 1 solation valve (FWIV) was ongoing when an instrumentation and control tecnnician placed his test leads on the incorrect terminal, resulting in the FWIV fully closing. The reactor operator insiediately initiated a tranual reactor scram. A test push button which would normally be utilized, was inoperable at the t'me.

This required the technician to utilize an engineering procedure, which requird Se placement of jumpers.

Following the manual trip a second engineered safety activrtion of the auxiliary feedwater (AFW) system occurred because of a shrink in the "C' steam generator, Anoperatorhadopenedthe"C"steamgeneratorpoweroperatorreliefvalve(PORV) from 10 to 35 percent open. An indicated level swell occurred because of the pressure decrease from the open PORV. When the PORY was closed, the actuation-setpoint for AFW in initiation was reached on the indciated low steam generator level.

Licensee management has decided to maintain the unit shutdown urtil a fontalized self-verification training program has been established and givrn to all i

maintenance and operations personnel. The unit will remain shu c - Nr approximately 10 days to allow repairs to a bellows in a low pre nuce turbine.

The licensee indicated that the unit was taken to Hode 4 because the need to establish the formalized training, l

Unit 2 entered their first refueling outage at approximately 1 a.m. en September 29, 1990.

Following the trip of Unit 1, the second units' caoloown was delayed to ensure sufficient steam was available to efficiently cooldown the first unit. Unit ? entered Mode 5 at 4:a7 a.m. on October 1,1990. %c licensee will perform a complete fuel off load during this refueling outage.

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

The state of Texas will be informed.

Region lY received notification of this occurrence by telephone from SRI at 9 a.m. on September 29, 1990. Region IV has informed EDO, NRR, and PA.

This information has been confirmed with a licensee representative.

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