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

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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  STP Nuclear Operating Company icon.png
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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