PNO-III-98-015, on 980201,reactor Scrammed from 96% Power Following Trip of Main Turbine.Main Turbine Trip Resulted from Main Generator Load Rejection Protective Signal. Investigation Continuing

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PNO-III-98-015:on 980201,reactor Scrammed from 96% Power Following Trip of Main Turbine.Main Turbine Trip Resulted from Main Generator Load Rejection Protective Signal. Investigation Continuing
ML20206R827
Person / Time
Site: Fermi DTE Energy icon.png
Issue date: 02/04/1998
From: Burgess B, Schweibinz E
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
To:
References
PNO-III-98-015, PNO-III-98-15, NUDOCS 9901200279
Download: ML20206R827 (1)


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  1. 4 February 4, 1998 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE PNO-III-98-015 l

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 Region III staff (Lisle, Illinois) on this date.

Facility Licensee Emergency Classification Detroit Edison Co. Notification of Unusual Event Fermi 2 Alert Newport, Michigan Site Area Emergency Dockets: 50-341 General Emergency i X Not Applicable l l

Subject:

UNIT REMAINS SHUTDOWN TO REPAIR RHR VALVE FOLLOWING REACTOR SCRAM On February 1, 1998, the reactor scrammed from 96 percent power following a trip of the main turbine. The main turbine trip resulted from a main generator load rejection protective signal. This signal was generated following the unexpected opening of breakers in both the station's 345KV 4 and offsite power electrical distribution systems. The 345 KV and the 120 KV systems continued to supply power to both safety-related and non-safety-related loads. Investigations are continuing to determine the ,

cause of the circuit breakers' opening. Plant and operator response to l l

the event were good.  ;

E l Post scram data analysis revealed that the main turbine reached 123 l l percent of nominal rated speed following the trip. Investigations are '

continuing to determine the cause of the speed increase.

Several weeks prior.to the scram, station operators observed a small l . increase in unidentified leakage into the drywell. In response, station

! operators conducted walkdowns in the drywell that revealed a leak from a check valve in the Division I low pressure coolant injection portion of the residual heat removal system (RHR) . The licensee decided to place the l plant in cold shutdown to repair the valve.

The plant is expected to remain shut down until Friday, February 6, 1998.

The State of Michigan will be notified. The information in this preliminary notification has been reviewed with licensee management.

There has been local news media interest in the shutdown.

This information is current as of 11 a.m. on February 4, 1998.

Contact:

EDWARD SCHWEIBINZ BRUCE BURGESS (630)829-9712 (630)829-9629 9901200279 980204 E' PDR I&E 1 i PNO-III-99-015 PDR L dI