ML20112H037

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Submits Plans & Schedule for Improvement of Reactor Water Level Measurement Sys,In Response to Generic Ltr 84-23. Yarway Columns & Cold Ref Column Will Be Replaced by Dual Cold Leg Arrangement During Sept 1985 Outage
ML20112H037
Person / Time
Site: Vermont Yankee File:NorthStar Vermont Yankee icon.png
Issue date: 03/28/1985
From: Murphy W
VERMONT YANKEE NUCLEAR POWER CORP.
To: Eisenhut D
Office of Nuclear Reactor Regulation
References
FVY-85-29, GL-84-23, NUDOCS 8504020103
Download: ML20112H037 (2)


Text

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VERMONT YANKEE NUCLEAR POWER CORPORATION RD 5, Box 169, Ferry Road, Brattleboro, VT c5301

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ENGINEERING OFFICE y

1671 WORCESTER ROAD y

FRAMINGHAM, MASSACHUSETTS 01701 TELEPHONE 617-672-8100 March 28,1985 United States Nuclear Regulatory Comission Washington, D. C.

20555

. Attention:

Office of Nuclear Reactor Regulation Mr. D. G. Eisenhut, Director Division of Licensing

References:

(a) License No. DPR-28 (Docket No. 50-271)

(b) Generic Letter No. 84-23, USNRC to All BWR Licensees of Operating Reactors, NVY 84-231, dated October 26, 1984 (c) Letter, VYNPC to USNRC, FVY 84-144, dated December 6,1984

Subject:

Reactor Vessel Water Level Instrumentation (Generic Lette* No. 84-23)

Dear Sir:

Pursuant to Generic Letter No. 84-23 [ Reference (b), Vermont Yankee Nuclear Power Corporation notified you by letter, dated December 6, 1984

[ Reference (c)], that we had performed an analysis of Vermont Yankee's Reactor Water Level (RWL) measurement system addressing the potential improvement categories pre'sented in Reference (b). At that time, we informed you that our analysis had identified several potential improvement options to Vermont Yankee's RWL measurement and instrumentation system and that, upon completion of our evaluation of the identified options, we would provide you with a description of our plans and proposed schedule. Based upon the results of <

our evaluation, our plans and schedule, for improving the Vermont Yankee RWL measurement system are detailed below.

Vermont Yankee intends to replace the existing Yarway Columns and cold reference column with a dual cold leg arrangement. The Yarway Columns are to be replaced to allow the reference legs to operate at a lower temperature, thus reducing the possibility of boiling / flashing the water in the reference legs. Replacement of the Yarway Columns will also minimize level inaccuracies resulting from density variations due to elevated drywell temperatures.

In addition to replacing the Yarway Column, the existing cold reference leg is also to be replaced to simplify calibrations.

Vermont Yankee intends to perform the replacement during the next outage scheduled to begin in September 1985.

Because the RWL measurement system is a 8504020103 e50328 DR ADOCK 050 1

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-U.S. Nuclear R:gulatory Commission March 28,1985 Page 2 VIII(MONT YANKlit? NUCLliAll POW 1511 COltPOltATION Safety Class System' required for normal operation and post-DBE, it will be seismically, supported.

We trust this response is satisfactory; however, should you have any further questions, please contact us.

Very truly yours, VERMONT YANKEE NUCLEAR POWER CORPORATION f

W Warren P Murphy Vice President and Manager of Operations WPM /ss DOC #0265C

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