ML20086H181

AO 50-271/72-15:on 721219,during HPCI Sys Surveillance,Hpci Steam Line High Differential Pressure Switch DPIS 23-77 Tripped at 200 Inches of Water.Sensor Immediately Reset & Verified

ML20086H181
Person / Time
Site:	Vermont Yankee
Issue date:	12/21/1972
From:	Rosalyn Jones VERMONT YANKEE NUCLEAR POWER CORP.
To:	US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20086H184	List: ML20086H181 ML20086H186
References
AO-50-271-72-15, VYV-2383, NUDOCS 8401160044
Download: ML20086H181 (1)

Text

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VERMONT YANKEIQ NUCLEAR POWER CORPORATION SEVENTY SEVEN OROVC STREET RuTLAxo, VF.l(MONT 037O1 VYV-2383 'e m P. O. DOX 157 VERNON. VERMONT c5354 December 21, 1972 7'

Director "'~ ,[I!

Directorate of Licensing U.S. Atomic Energy Commission j gq ,j } ) Q'(g ff Washington, D.C. 20545 i DEC291972 -!!

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REFERENCE:

Operating License DPR-28 T Docket No. 50-271 - e , , ,e Abnormal Occurrence No. A0-72-15 k

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Centlenen:

As defined by Technical Specifications for the Vermont Yankee Nuclear Power Station, Section 6.7.B.d, we are reporting the following Abnormal Occurrence as A0-72-15.

At approximately 1200 on December 19, 1972 while performing routine surveillance on the llPCI system, the IIPCI steamline high differential

, l pressure switch (DPIS 23-77) was found to be tripping at 200 inches of l 1 water. This is above the value of 180 +5 inches of water specified bf f Table 3.2.2.2 of Technical Specifications. This sensor functions as an energized contact to auto close the IIPCI isolation valves on a steam line high differential (line break) pressure, The reactor was operating I at approximately 55% at the time of this incident.

l l r! The sensor was immediately reset, functionally tested, and verified I /

l to be operable within the tolerance specified. This remedial action was I

( > l4 completed in a time span which precluded the necessity of further action.

(/'/ The Plant Operations Review Committee concluded that although the pressure switch actuated above the specified pressure, the logic would

}f have actuated at the proper pressure because the companion switch (DPIS i

g s 23-76) was set properly and each one provides isolation via a one-of-

\' E I two-once logic. Due to the relatively 'small discrepancy between the "as found" and the as specified setting, no additional surveillance yi Q beyond that regularly scheduled was deemed necessary for the subject switch.

1 Very truly yours,

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,s - [ VERMONT YANKEE NUCLEAR POWER CORPORATION c-8401160044 721221 Robert F,t ones

{DRADOCK05000 Plant Superintendent y 7101 DUE/rpb OPY FFNT T?PCIONa/ - _._;

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