ML20084E111

AO 50-244/74-19:on 741204,during Monthly Surveillance Test PT-9,undervoltage Relay 274/11B Failed.Caused by Scale Accumulation on Armature Plunger Opposite Upper Guide Bearing.Plunger Polished

ML20084E111
Person / Time
Site:	Ginna
Issue date:	12/05/1974
From:	Platt C ROCHESTER GAS & ELECTRIC CORP.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML20084E113	List: ML20084E111
References
AO-50-244-74-19, NUDOCS 8304140107
Download: ML20084E111 (1)

Text

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ROC ll ESTER GAS AND ELECTRIC CORPORATION o 69 EAST AVGNUE. .iOCHESTER. H.Y.14M9 T c L E P**ON I aata coot tie 546 2700 Ginna Station December 5, 1974 Mr. James P. O'Reilly, Director l Directorate of Regulatory Operations

Region 1 y

( U. S. Atcmic Energy Cc= mission (.

i 631 Park Avenue '

k King of Prussia, Pa. 19406

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I

Subject:

Abnormal Occurrence 74-19: Failure of Undervoltage Belay During k Monthly Surveillance Test

{ Ginna Station

! Docket #50-244 t

i i

Dear Mr. O'iicilly:

I During the pcrformance of the Monthly Serveillance Procedure PT-9, "Under-voltage and i'nderfrequency Protection" on Dcccaber 4, 1974, upon opening the knife switches for the solenoid coil of primary undervoltage device .

274/118. It was discovcred that tne device armature did not irop down to asswae its' de-caergized position. As a result of this f ailure to operate, the Reactor Trip Undervoltage Protection sir,nal was not generated for this i relay. The knife switches were it=ediately opened again, an<' this second l t'ime the relay operated properly. The other thrce undervoltage relays on the 4160 volt bus were tested and they operated properly.

RG&E Relay Department was contacted and a relay can came to the station to l Investigate the failure. .

4 f

A scale accumulation was noted on the armature plunger opposite the area of

, the upper guide bearing. Thi accumulation uas similar to that reported as l abnormal occurrence 73-1 on May 29, 1973. All four undervoltage relays were

removed, cac at a tire, and the scale accumulation was removed and the plun-l ter polished. Upon returning the devices to service, the applicable sect' ion of PT-9 procedure was performed to verify operability.

l f Very truly yours, g41401oy741213 ADOCK 05000244

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S Charles E. Platt PDR Superintendent cc: Mr. J. F. O' Leary, AEC ,g[i .

Mr. G. J. Swarthout, RC&E Hr. L. D. L'hite, Jr. RG&E

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