PNO-I-87-107, on 871117,turbine Reactor Tripped Due to Spuriously Generated Turbine Thrust Bearing Trip.Caused by Technician Inadvertently Tripping Power Switch on Turbine Rotor Position Drawer.Offsite Transformer Inspected

PNO-I-87-107:on 871117,turbine Reactor Tripped Due to Spuriously Generated Turbine Thrust Bearing Trip.Caused by Technician Inadvertently Tripping Power Switch on Turbine Rotor Position Drawer.Offsite Transformer Inspected

ML20236R418
Person / Time
Site:	Beaver Valley
Issue date:	11/18/1987
From:	Wiggins J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
To:
References
PNO-I-87-107, NUDOCS 8711230267
Download: ML20236R418 (1)

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DCS No: 50412871117 Date: November 18, 1987 )

i PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE--PNO-I-87-107 This preliminary notification constitutes EARLY notice of events of POSSIBLE ~ safety

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or public interest significance. The information is as initially received without "

verification or evaluation, and is basically all that is known by the Region I staff on this date.

Facility: Duquesne Light' Company Licensee Emergency Classification:

Beaver Valley Unit 2 Notification of Unusual Event Shippingport, Pennsylvania Alert Docket No. 50-412 Site Area Emergency

. General Emergency X Not Applicable

Subject:

TURBINE GENERATOR TRIP AND' LOSS OF OFFSITE POWER l

On November 17 at 2:06 p.m., the unit tripped from full power after a technician '

inadvertently tripped a power swith on the turbine rotor position drawer causing a turbine / reactor trip due to a spuriously generated turbine thrust bearing trip.  !

Immediately following the trip, a series of breaker automatic operations resulted in

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loss of offsite power for approximately 17 seconds until one of the two offsite power sources was reenergized automatically. In response to the loss of all AC power, both emergency diesel generators (EDGs) automatically started and loaded. Natural circulation was terminated after approximately 5 minutes when reactor coolant pumps were restarted. One EDG was secured. The second EDG remained running and providing power for about 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> following the trip while the licensee performed a physical inspection of the remaining offsite transformer. No damage was identified, and the second offsite power supply was restored and the second EDG secured at about 10:00 p.m.

The licensee is currently in Mode 3 and investigating the event. Resolution of the loss of power event will be completed and discussed with NRC Region I management. prior to plant startup.

A team of specialist inspectors have been dispatched from Region I in response to'the event.

The Commonwealth of Pennsylvania has been notified. '

CONTACT: J. Wiggins (FTS 488-1224)

DISTRIBUTION:

H. St. MNBB Phillips E/W Willste Mail: ADM:DMB Chairman Zech EDO NRR NMSS DOT:Trans only Comm. Roberts PA OIA RES Comm. Bernthal OGC AEOD NRC Ops Crt Comm. Carr Comm. Rogers ACRS Air Rights INPO----

SECY SP NSAC----

CA PDR Regional Offices TMI Resident Section RI Resident Office Licensee: '

(Reactor Licensees) ,

Region I Form 83 h 2 g 67 87111e (Rev. August 1987) PNO-I-87-107 PDR \

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