ML20059N712

Responds to Util Re Discovery of Flaws in Feedwater Check Valves 27B & 96B.NRC Believes Valve 96B Should Be Reinspected at Next Reload Outage to Verify Util Fracture Mechanics Analyses

ML20059N712
Person / Time
Site:	Vermont Yankee File:NorthStar Vermont Yankee icon.png
Issue date:	10/10/1990
From:	Fairtile M Office of Nuclear Reactor Regulation
To:	Tremblay L VERMONT YANKEE NUCLEAR POWER CORP.
References
NUDOCS 9010170174
Download: ML20059N712 (5)

Text

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1. 9 UNITED sT ATES

-[^ 3..< h NUCLEAR REGULATORY COMMISSION r,, j ,W A$HlyGTON, D. C. 20665 1,,

/ October 10, 1990 I -

Docket No. 50-271 I I

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Mr. L. A. Trenblay 3 Licensing Engineer  ;

Vermont Yankee Nuclear Power Corporation 580 Main Street-Bolton, Massachusetts 01740-1398 4

Dear Mr. Tremblay:

P

SUBJECT:

VERMONT YANKEE FEEDWATER CHECK VALVES 27B AND 968 By. letter dated October 4,1990, the Vermont Yankee Nuclear Power Corporation i

-informed the HRC of flaws in Feedwater Check Valves 278 and 96B. 'Through

, ultrasonic examination of valve 27B you have characterized the flow depth as ,

0.50 inches and contained totally within the width of a Ste111tle wear padt. )

the valve wall thickness at the flaw location was stated to be 2.6 inches.

This flaw is not as deep as the 0.65 inch flaw in valve 28B which you found ,

during your 1989 refueling outage.

The flaw in valve 27B is in excess of the ASME Section XI acceptance criteria; this. situation; therefore, requires NRC approval: prior to restart of the '

Vermont Yankee plant from its current reload outage.  !

In regard to the flaw discovered in 1989, in valve 28B, you'provided analyses, dated March 28, 1989 and March 16, 1990, that provided an evaluation of that' flaw. We found these analyses acceptable _in our Safety Evaluation of April 19, ,

1990. You committed to replace valve 28B during the 1990 outage and to implement an enhanced leakage monitoring program for valve 28B. .

Your analyses for valve 288 bounds the flaw for Lyalve 278. In addition, your letter of.0ctober 4,1990, committed to replace valve 27B at the next reload outage and to provide enhanced leakage monitoring through use of a leak monitoring tape. Your October 4 1990, letter also noted that valve 968 contained a 0.15-inch flaw which is within the acceptance limits of ASME Section XI. However, the staff believes you should reinspect valve 968 at the next reload outage to verify your fracture mechanics analyses.

9010170174 901010 DR ADOCK 0500 1 C130 D Foi go

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Mr. L. A. Tremblay ,

,2 - October 10, 1990  ;

i Based on the above, namely that your previous analyses of March 28, 1989 and March 16 1990, bound the flaw in valve 27B and your commitment to re) lace 27B and provide enhanced leakage monitoring, we conclude that feedwater c1eck valve 27B will be capable of functioning for one additional fuel cycle. I

, Sincerely, l Original signed by:

Morton B. Fairtile, Senior Project Manager Project Directorate I-3 Division of Reactor Projects - I/11 Office of Nuclear Reactor Regulation cc: See next page e.

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30 lo /S /90 90 10 /q /90 10 /tD/90 OFFICIAL RECORD COPY Document Name: CHErk VALVES 27B & 96B /VY 4

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1 Mr. L. A. Tremblay, Senior Lictnsing. Engineer Vermont Yankee

CC

i l Mr. J. Gary Weigand Honorable James J. Eaton L President & Chief Executive Officer State of Vermont l l Vermont Yankee Nuclear Power Corp. 109 State Street R.D. 5, Box 169 I Montpelier, Vermont 05602  !

! Ferry Road Brattleboro, Vermont 05301 James Volz, Esq.

i Speciai Assistant Attorney General '

Mr. John DeVincentis, Vice President Vermont Department of Public Service Yankee Atomic Electric Company 120 State Street 580 Main Street Montpelier, Vermont 05602 I Bolton, Massachusetts 01740-1398 G. Dana Bisbee, Esq. ) I Regional Administrator, Region 1 Office of the Attorney General l U. S. Nuclear Regulatory Comission Environmental Protection Bureau 1 475 Allendale Road State House Annex King of Prussia, Pennsylvania 19406 25 Capitol Street Concord, New Hampshire 03301-6937 Ropes & Gray Mr. James Pelletier .

One International Place Vice President - Engineering Boston, Massachusetts 02110 Vermont Yankee Nuclear Power Corp.

P.O. Box 169, Ferry Road Mr. W. P. Murphy, Senior Vice President, Brattleboro, Vermont 05301 Operations '

Vermont Yankee Nuclear Power Corporation Resident Inspector R.D. 5, Box 169 Vermont Yankee Nuclear Power Station Ferry Road U.S. Nuclear Regulatory Comission Brattleboro, Vermont 05301 P.O. Box 176 Vernon, Vermont 05354 Mr. George Sterzinger, Comissioner Vermont Department of Public Service John Traficonte Esq.  :

120 State Street, 3rd Floor Chief Safety Unit Montpelier, Vermont 05602 Office of the Attorney General -

One Ashburton Place, 19th Floor Public Service Board Boston, Massachusetts 02108 State of. Vermont 120 State Street Adjuicatory File (2)

Montpelier, Vermont 05602 Atomic Safety and Licensing Board Panel Docket Chairman, Board of Selectmen U.S. Nuclear Regulatory Comission Town of Vernon Washington, D.C. 20555' Post Office Box 116 Vernon, Vermont 05353-0116 Robert M. Lazo, Chairman Atomic Safety and Licensing Board Mr. Raymond N. McCandless U.S. Nuclear Regulatory Comission '

Yermont Division of Occupational Washington, D.C. 20555 and Radiological Health Administration Building Montpelier, Vermont 05602 i

~sm -- . . . _ - - - . . - . - - -

c'  !

I Mr. L. A. Tremblay , Vermont Yankee I cc:

l Frederick J. Shon Administrative Judge Atomic Safety and Licensing Board U.S. Nuclear Regulatory Comission Washington, D.C. 20555 Jerry R. Kline Administrative Judge .

Atomic Safety and Licensing Board U. S. Nuclear Regulatory Comission Washington, D.C. 20555 1

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Distribution

' Docket Fils MRC & Local PDRs -

'PDI-3 R/F S.'Varga B. Boger M. Rushbrook EMEB M. Fairtile R. Wessman OGC E. Jordan ACRS-(10)

'J. Johnson, Region 1 C.Y. Cheng B. Elliot i