ML20086H181

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


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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

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Director Directorate of Licensing j

U.S. Atomic Energy Commission ff i

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Washington, D.C.

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REFERENCE:

Operating License DPR-28 q

Docket No. 50-271

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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.

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The sensor was immediately reset, functionally tested, and verified I

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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.

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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 g

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

\\' E I two-once logic.

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

1 Very truly yours,

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

{DRADOCK05000 Plant Superintendent y

1 7 01 OPY FFNT T?PCIONa/

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