ML20086E116

Updated AO 73-20:on 730706,drywell Purging & Vent Exhaust Valve V16-19-7A Would Not Close.Mechanical Binding Will Be Investigated & Valve Overhauled During Future Shutdown.Valve Presently Deactivated in Closed Position

ML20086E116
Person / Time
Site:	Vermont Yankee
Issue date:	07/10/1973
From:	Riley B VERMONT YANKEE NUCLEAR POWER CORP.
To:	US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20086E119	List: ML20086E116 ML20086E124
References
AO-73-20, VYV-2785, NUDOCS 8312060061
Download: ML20086E116 (1)

Text

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[ VERMONT YANKEM NUCLEAR POWER CORPORATION SCVENTY SEVEN OROVE STRECT Rim.Axn, W:lutONT 03701 VYV 2785 P. O. BOX 157 VEHNON, VERMONT 05354

- July 10, 1973

- , \ W }lf) l Director & + V Directorate of Licensing > RfCibf0<

U.S. Atomic Energy Commission b ,fy[ g yg ',,,,

Washington, D.C. 20545 Z .

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REFERENCE:

Operating License DPR-28 {k $c"g[f[

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Docket No. 50-271-Abnormal Occurrence No. A0-73-20 \@Y/ ,y , d

Dear Sir:

As defined by Technical Specifications for the Vermont Yankee Nuclear Power Station, Section 6.7.B.1, we are reporting the following Abnormal Occurrence as A0-73-20.

At 0800 on July 6,1973, while purging the drywell via RTF-5, V16-19-4, and V16-19-7A, the Drywell Purging and Vent Exhaust Valve V16-19-7A would not close. The inoperability of Valve V16-19-7A exceeds the Limiting Conditions for Operation as defined by Section 3.7. A.2 of Technical Specifications. The subject section states that Primary Containment Integrity shall be maintained at all times when the reactor is critical or when the reactor water temperature is above 212*F and fuel is in the reactor vessel. The reactor was shutdown and cooling down at the time of the incident. Reactor temperature was 300'F and reactor pressure was 50 psig.

I Downstream valve V16-19-4 was shut and RTF-5 was secured it.acdiate-f ly. The valve operator was removed. The valve was manually actuated and found to be binding internally at the lotrer bushing, j)K, '

1hc Plant Operations Review Committee reviewed this incident and

,/vU recommended that the mechanical binding be investigated and the valve U( overhauled during a future shutdown. At present, the valve is deactivated In the closed position and will not be used when primary containment l integrity is required.

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Very truly yours, 8312060061 730710 VERMONT YANKEE NUCLEAR POWER CORPORATION PDR ADOCK 05000271""

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S B.W. Riley C ( 3 ga'(f)p

/A I Plant Superintendent -

( 5443 BWR/1k l COPY SEN1' REGION

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