ML20086K401

Telecopy AO 74-39:on 740723,static Inverter Power Supply in RCIC Sys Tripped During Start of Recirculation Pump.Cause Unknown.Corrective Action to Be Determined

ML20086K401
Person / Time
Site:	Peach Bottom
Issue date:	07/24/1974
From:	Ullrich W PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML20086K394	List: ML20086K391 ML20086K401
References
AO-74-39, NUDOCS 8401270068
Download: ML20086K401 (1)

Text

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1 Mr. Ja::es P. O'R]'

y, Director /

l United States Ato . c Energy Co=ission l Directorate of Regulatory Operations 631 Park Avenue King of Prussia, Pennsylvania 19406 I

Subject:

Abnoreal Occurrence 24-Hour Notification I

1 I Confirming W. T. U11 rich's phone conversation with Mr. Tom Shedlovsky, A.E.C. Region 1 Regulatory Operations Office on July 24, 1974.

Reference:

Licenne Number DPR-44, A=endment Number 1 Technical Specification Tabic 3.2.B Report No.: 50-277-74-39 Report Date: July 24, 1974 Occurrence Date: July 23, 1974 Facility: Peach Botten Atomic Power Station R. D. 1. Delta, Pennsylvania 17314 Identification of Occurrence:

Static invertcr power supply in the Reactor Core Icolation Cooling System (RCIC) tripped during a start of a recirculation pt=p.

Conditions Prior to Occurrence:

The reactor had scramed from 30% power just prior to this occurrence.

Description of Occurrence:

During a restart of a reactor recirculation pu=p, following a reactor scram, the RCIC inverter failure alarm annunciated in the main control room. The inverter was in:cediately reset.

Designation of Apparent Cause of Occurrence:

The cause of the trippings of the ntatic inverter has not been found.

It is believed that the inverter trips due to a D.C. bus transient following the start of a large A.C. motor.

Analyais of Occurrence:

The operation of the RCIC nystem was not necessary at the time of the tripping. The reactor led jur.t cera=cd on a turbine trip fres high se renctor enter level. Tecauae of this and the imediate restart of the inverter this occurrence has ninical safety implications.

QQ cn o 00 Corrective Action:

"O The trippings of the inverters are currently under investigation by h the Philadelphia Electric Co.pany Engineering and Rescarch Departnent.

s Pailure Data: [ $

$< Three other trippings of the inverter have been reported air A0-50-277-74-14, og A0-50-27 7-74-20 and is0-50-277-74-37. l [J caax , , ,

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