ML20086D895

AO 73-01:on 730109,during Reactor Startup from Cold Shutdown,No Indication Observed on Intermediate Range Monitor (IRM) Channels B,D & F While Increasing Power from Source Range Monitor Range to Irm.Caused by Blown Fuse

ML20086D895
Person / Time
Site:	Vermont Yankee
Issue date:	01/15/1973
From:	Riley B VERMONT YANKEE NUCLEAR POWER CORP.
To:	US ATOMIC ENERGY COMMISSION (AEC)
References
AO-73-01, AO-73-1, VYV-2409, NUDOCS 8312050334
Download: ML20086D895 (1)

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VERMONT Y ANKEE IUCLEAR POWER CORPORATION o SEVEN1 Y SEVCN OROVC STRECT RUT 1,ASD, VEltMONT OG701 ft E PL.Y TO:

VYV-2409 p. o. nox is7 VERNON, VCRMONT oS354 January 15, 1973 4 s M, , ' ~

Director Directorate of Licensing ,[ ,

4 U.S. Atomic Energy Commission J l'

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Washington, D.C. 20545 ,  :.. .

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Operating License DPR-28 .-- i

REFERENCE:

Docket No. 50-271 Q O

s Abnormal Occurrence No. A0-73-01 g, ~ y ,. /

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Dear Sir:

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As defined by Technical Specifications for the Vermont Yankee Nuclear Pcuer Station, Section 6.7.B.d, we are reporting the follouing s--

Abnormal Occurrence as A0-73-01.

At approxinately 2120 on January 9, during a reactor startup from cold shutdown, no indication was observed on IRM channels B, D, and F while increasing power f:om the SR>i range to the IR>l range. This -

inoperability of the IPl! exceeds the Limiting Condition for Operation "

as defined by Specification 3 of Table 3.1.1 of Technical Specifications. .

The subject section requires two IR>l channels per trip system to be operable with the reactor mode switch in the Startup position. The reactor was critical on the SRM power range at this time,

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A manual trip was immediately imposed on RPS Channel B. The three 1131 channels were restored to service and verified to be operable and RPS Channel B reset. This action was completed in a tine span which precluded the necessity of inserting control rods as required by note 3 a) to the table.

The Plant Operations Review Committee concluded that the inoperability was the result of a blown fuse in the power supply within each of the IRM drawers. These f ailures l' ave been attributed to voltage spikes imposed during the LNP and transforner load testing conducted earlier that day.

Plant procedures will be modified to incorporate a requirement to verify operability on each of the individual nuclear instruments prior to rod withdrawn. ,7

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0312050334 730115 ,

x Very truly yours, PDR ADOCK 05000271 S PDR ~ - VERMONT YANKEE NUCLEAR POWER CORPORATION f}'f

" JAN 221973 -

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W bEh K B.W. Riley 'g3-9 Assistant Plant Superintendent

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