ML20086E652

AO 74-06:on 740418,both Access Doors to North Entrance to Reactor Bldg Found Partially Open.Caused by Personnel Failing to Verify Closure.Design Adequacy Under Review

ML20086E652
Person / Time
Site:	Vermont Yankee
Issue date:	04/25/1974
From:	George Thomas VERMONT YANKEE NUCLEAR POWER CORP.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML20086E654	List: ML20086E652 ML20086E657 ML20086E664
References
AO-74-06, AO-74-6, VYV-3244, NUDOCS 8312070470
Download: ML20086E652 (2)

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VERMONT YANKEE NUCLEAR POWER CORPORATION SCVCNTY CCVCN OROVC STRCCT Ruri.Axo, Vim >10NT 03701

'-3M P.O.DOX 157 VERNON. VERMONT os354 April 25, 1974 e \r0,j Director Directorate of Regulatory Operations, Region I (

United States Atomic Energy Commission -

631 Park Avenue S- t.

King of Prussia, Pennsylvania 19406

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REFERENCE:

Operating License DPR-28 p.((@p gr. p Docket No. 50-271 VS f

Abnormal Occurrence No. A0-74-06 g, 4-

Dear Sir:

Ao dc.fi..cd by Tcchnical Specificctiene fer the Vera'- V a at'a a Nuclear Pouer Station, Section 6.7, we are reporting the follcwing Abnormal Occurrence as A0-74-06.

At approximately 1115 on April 18, 1974, while maintenance was being performed on the Reactor Building Exhaust Fans, both access doors to the ncrth catrance of the Reactor Building were discovered to have been left partially open. This situation existed for approximately two I minutes prior to both doors being closed. It was determined that this condition was in violation of Technical Specifications, Sectica 3.7.C, in that the integrity of the secondary containment system was not maintained during that period of tire. The reactor was operating at 83.4% power at the time of this incident.

Subsequent review of circumstences leading to the incident indicated that the acccas doors were not verified closed by plant personnel utilizing them during this period of time.

The Plant Operations Review Connittee reviewed the incident and concurred that the probable cause uas as' stated above. In order to preclude occurrences of this nature, the following recom:r.cadations were made:

1. Request the Nuclear Servjees Division to undertake an engineering reviau of both Reactor Building air locks to evaluate their design adequacy. ,

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8312070470 740425 j/

PDR ADOCK 05000271 y rf OI COPY RENT REGIO

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'VCRMONT YANKEE NUCLEAR POWER CORPORATioh

• ' directorate of Regulatory Operations, l April 25, 1974 Page 2

2. Modify plant operating procedures to require that both Standby Gas Treatment System fans be operating in the .

cvent that normal Reactor Building ventilation is secured.

This will assist in maintaining positive door closure.

3. Install a door at the went access ramp to the Reactor Building in order to decrease the probability of Turbine Building ventilation being influential in prohibiting Reactor Building door closure.

4. Install an audible alarn device on the north Reactor Building air lock doors which would sound locally in the event either door was not fully closed.

5. Irpress on all plant personnel that they have a responsibility for assuring cecondary containment integrity.

Very truly yours, VERMONT YANKEE NUCLEAR POWER CORPORATION il t i

,,4.L$ -)-l *.i' tAS G.S. Thocas Assistant Plant Superintendent WFC/kbd l

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