PNO-III-85-076, on 850825,recirculation Pump B Problem Resulted in Brief Power Increase from 2.9 to 8.8%.Reactor Operators Tripped Pump After Failing to Reduce Pump Speed. Testing Disclosed No Problems W/Speed Control Circuitry

From kanterella
(Redirected from ML20134L503)
Jump to navigation Jump to search
PNO-III-85-076:on 850825,recirculation Pump B Problem Resulted in Brief Power Increase from 2.9 to 8.8%.Reactor Operators Tripped Pump After Failing to Reduce Pump Speed. Testing Disclosed No Problems W/Speed Control Circuitry
ML20134L503
Person / Time
Site: Fermi DTE Energy icon.png
Issue date: 08/26/1985
From: Chrissotimos N, Landsman R
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
To:
References
PNO-III-85-076, PNO-III-85-76, NUDOCS 8509030304
Download: ML20134L503 (1)


PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE--PNO-III-85-76 Date August 26, 19 This preliminary notification constitutes EARLY notice of events of POSSIBLE safety or public interest significance. The information is as initially received without veri-b fication or evaluation, and is basically all that is known by the staff on this date.

Facility: Detroit Edison Company Licensee Emergency Classification:

Fermi 2 Nuclear Plant Notification of an Unusual Event Newport, MI 48166 Alert Site Area Emergency Docket No: 50-341 General Emergency XX Not Applicable

Subject:

BRIEF INCREASE IN POWER LEVEL At 7:05 p.m. on August 25, 1985, the reactor experienced a brief increase in power level from 2.9 per cent to 8.8 per cent because of a problem with the B recirculation pump. The plant has a full power Operating License, but the licensee has committed to a 5 per cent power limitation, pending completion of reviews resulting from the July 2,1985, premature criticality incident. The limitation was documented in a Confirmatory Action Letter, issued by Region III (Chicago) on July 16, 1985.

The licensee reported that the B recirculation pump unexpectedly increased from its minimum 30 per cent pump speed to 60 per cent. The speed increase is believed to have occurred while plant personnel were installing instrumentation on the recirculation pump speed control system.

The increased recirculation water flow through the reactor resulted in the brief power increase (approximately 15 seconds). Reactor operators were unable to reduce the pump speed and therefore tripped the pump. The reduced recirculation flow decreased the reactor power level. The unit remained in operation.

Subsequent testing disclosed no problems with the recirculation pump speed control circuitry, and at 9 a.m. , August 26, 1985, the pump was placed back in operation. As of that time, the plant was at 2.8 per cent power.

The brief increase in power level did not affect the safety of the plant. The Resident Inspector is reviewing the circumstances of the incident.

There has been local news media interest in the incident.

The State of Michigan will be informed.

Region III was notified of the incident by the Resident Inspector about 8:30 p.m.,

August 25, 1985. T is information is cur ent as of 11 a.m., August 26, 1985.

CONTACT: R. andsma N ssotimos FTS 388-5587 FTS 388-5716 DISTRIBUTI  :

E/W[lg H. St. MNBB//5$ Phillips $ O [ Willste).30 Chairman lladino ED0 NRR IE NMSS Comm. Roberts PA OIA RES Comm. Asselstine MPA AEOD Comm. Bernthal ELD Air Rightsh.'O/ MAIL:

Conn. Zech SP INP0 M., ADM:DMB SECY NSAC 4:ff DOT: Trans Only ACRS CA Applicable Reji,ident SiteMdC PDR Regions I2M IIffB , IV4Z2,3, VA 06 Licensee (Corporate Office) I d D 85090gO4850826 Rev. 07/06/84

-111-85-076 PDR