PNO-V-86-055, on 860828,reactor Trip Occurred Due to Generator/Turbine Trip.Caused by Overexcitation After Small Adjustment to Reactive Load.Vendor Contacted to Investigate Problem.Startup Schedule Pending

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PNO-V-86-055,on 860828,reactor Trip Occurred Due to Generator/Turbine Trip.Caused by Overexcitation After Small Adjustment to Reactive Load.Vendor Contacted to Investigate Problem.Startup Schedule Pending
ML20206R151
Person / Time
Site: Palo Verde Arizona Public Service icon.png
Issue date: 08/29/1986
From: Miller L, Zimmerman R
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
To:
References
PNO-V-86-055, PNO-V-86-55, NUDOCS 8609050343
Download: ML20206R151 (1)


PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE--PNO-V-86-55 Date: 08/29/86 This preliminary notification constitutes EARLY notice of events of POSSIBLE safety or public interest significance. The information presented is as initially received without verification or evaluation and is basically all that is.known by Region V staff on this date.

FACILITY: Arizona Nuclear Power Project Emergency Classification Palo Verde Unit 2 Notification of Unusual Event DOCKET NO. 50-529 Alert Site Area Emergency General Emergency

_XX_Not Applicable

SUBJECT:

UNIT 2 REACTOR TRIP FROM A MAIN GENERATOR TRIP - OUTAGE GREATER THAN 48 HOURS Tha Unit 2 reactor tripped from a power level of 80% at 10:55 am on August 28. The reactor trip was preceded by a generator / turbine trip which resulted in the reactor pressure rc:ching the trip point of 2383 psia. No engineered safety features were actuated. All systems performed as required except the reactor power cutback (RPCB) system, which had been put into service for the first time during the latest power operation at 80%. The RPCB cystem had not been tested yet and was scheduled for testing when a power level of 100% was achieved.

Th2 generator tripped from over-excitation shortly af ter a small adjustment to the reactive load had been completed. Recorder traces supported a valid over-excitation condition. A trip from an over-excitation problem occurred at Unit 2 on August 25. Investigative findings following that trip revealed an improperly calibrated field current reasuring transducer, which was providing a full load field current signal to the generator protective circuitry wh:n, in fact, the field current was significantly less than the full load.

The licenscc has contacted the vendor, General Electric Company, to provide the expertise to investigate the problem related to the generator trip. No schedule for startup has been established pending completion of the investigation.

The licensee has notified the local media.

This information is current as of August 29 at 9:00 am, PDT.

CONTACT: R. Zimmerman, Sr. Resident Inspector L. Miller (602) 386-5760 (415) 943-3869 UISTRIBUTION H St. MNBB Phillips E/W Willste Air Rights / l 14 ail:

Chairman Zech EDO NRR IE NMSS ADM:DMB Comm. Roberts PA OIA RES DOT:Trans Only Comm. Asselstine MPA aEOD Comm. Bernthal ELD Comm. Carr Regions:

SECY INP02 l5T NSAC / 7 7 ACRS Licensee: h/' C 6b CA (Reactor Licensees) REGION V: FORM 211 PDR Resident Inspector __ (Revised 3/14/83) 8609050343 860829 PDR 13dE l PNO-V-86-055 PDR L

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