ML20086D615

Updated AO 73-33:on 731204,pressure Switch Ps14-44B Failed to Actuate at Required Setpoint,Resulting in Failure of B Core Spray Subsystem.Caused by Setpoint Drift.Switch Reset & B Core Spray Subsystem Declared Operable

ML20086D615
Person / Time
Site:	Vermont Yankee
Issue date:	12/12/1973
From:	Riley B VERMONT YANKEE NUCLEAR POWER CORP.
To:	US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20086D605	List: ML20086D603 ML20086D615
References
AO-73-33, VYV-3093, NUDOCS 8312020423
Download: ML20086D615 (2)

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ca ') V 141 MON'1' Y A Nisicic N 1mLicAR 1 SOW Icit Colt 1501: A'I'lON ti t.v t' N T Y tA c Vc N OH OVc ti f H r t' T Rtrri.Asn, W:nr* ION'T 07701 MtPLV T he M -3093 s., o,giox g3y VenNON, VUNONT 05351 December 12, 1973 -

Diiector Directorat e of Licensing gN>spl llk[.,?

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REFERE!!CC: Operating 1.icenne DPR-28 C #A Docket No. 50-271 $\ %g?g8+ 4 Abnormal Occurrence No. A0-73-33 (>//

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Gentlemen:

An defined by Technical Specifications for the Vermont Yankee Nocionr Power St ation. Section 6.7.d.1. we are reporting the following Abnorual occurrenet- as A0-73-33.

At approximately 1530 on December 4,1973, uhile performing a monthly functional tent on the Core Spray System, preenure nwitch pS14-448 failed to actuate nt the required netpoint of 100(+10) pnig an specified in Tabic 3.2.1 of the Technical Specifications.

Functionally, thin r, witch operaten an a prennure perminnive in the Automatic Deprennurization Syntem indicating the f act that a core npray pump in running.

As a renult of the nuitch f ailure, the "B" Core Spray Subnyntem was declared ineperable at 1535, and the cperahtlity verification requi red by Sect ien 4.S. A.2 of the Technical Specificationn Wan begun.

The reactor van operat ing at approximately 68% power ut the time of thin lucident.

• ihe nuit ch was imeediately renet, f unctionally tented and verified.

to be operable within the npeclited tolerance. The "d" Core Spray Subnyntem van declared operable at 1545 on the date of the occurrent.c.

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Di rect orat e of 1.icenning De cer .be r 12, 1973 Page 2

'1 h o Plant openations Peview Committee concluded tlint titin failure vmi on l'iolated inntance of Itin t rumetit netpolint drift due to tlie fact that p.tra t taurveillance perf ortaed on tills tientsor f.tlled to ludicate a p re v ioun problen. It van f urther recor:.rs nded that the nentsor be tented two weekn af ter the incident to confirta ita functional reliability.

Very t ruly youru ,

VI:lul0NT YANK!:1; NUCl.1:AR POWl:R CORPORATION D e II.U. I;11ey -

u Plant S upe rint endent.

WFC/kbd

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