ML20086E072

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AO 75-11:on 750511,intermediate Range Monitor Channel E Failed to Respond to Increasing Neutron Flux Level.Cause Not Stated.Reactor Protection Sys Trip Sys a Manually Tripped
ML20086E072
Person / Time
Site: Vermont Yankee Entergy icon.png
Issue date: 05/12/1975
From: Riley B
VERMONT YANKEE NUCLEAR POWER CORP.
To: James O'Reilly
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML20086E070 List:
References
AO-75-11, VYV-3872, NUDOCS 8312060040
Download: ML20086E072 (1)


Text

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VERA10NT YANKEE NUCLEAR POW 3R CORPORATION -

  • s a SCVENTY GCVCN OROVC STRCCT  %

RUTLANu, VimMONT 05701 VYV-3872 p n x :57 VERNON. VERMONT o5354 May 12, 1975 United States Nuc1 car Regulatory Commission Office of Inspection and Enforcement Region 1 631 Park Avenue King of Prussia, Pennsylvania 19406 ATTENTION: James P. O'Reilly, Director

REFERENCE:

Operating License DPR-28 Docket No. 50-271 Abnormal Occurrence No. A0-75-11 (24 Hour Report)

9. .

Dear Sir:

'4 As defined by Technical Specifications for the Vermont Yankee Nuc1 car Power Srntinn, Socrion 6.7, ua nra rapnvHng tha rn iin.fng Abn e :1 Occurrence as A0-75-11 and confirming our telephone conversation with your office.

, At approximately 1144 on thy 11,1975, during a plant startup from a iot shutdown condition, it was observed when entering the IRM range that IRMChannciEdidnotrespondtotheincreasingneutronfluxlevel.) Prior o this observance, IRM Channci C was bypassed due to the inoperability of its detector drive subsystem. - Specification 3 of Table 3.1.1 of the Technical Specifjcations requires two IRM channels per trip system to be operable with the reactor mode switch 1n the Startup position.

A manual trip was immediately imposed on RPS Trip System A in accordance with Note 3 of Tabic 3.1.1 of the Technical Specifications. This condition was maintained until the reactor mode switch was placed in the Run position at 1213 ea May 11, 1975. All three IRM channels in RPS Trip System B were .

operabic during the plant startup.

Very truly yours .-

  • ) f) .

Bradford W. R Icy N -

Plant Superintendent ilE/kbd ,

i t 9312060040 750523 .

PDR ADOCK 05000271 8 PDR ~^

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