ML20209E880
| ML20209E880 | |
| Person / Time | |
|---|---|
| Site: | Seabrook  |
| Issue date: | 05/15/1986 |
| From: | George Thomas PUBLIC SERVICE CO. OF NEW HAMPSHIRE |
| To: | Murley T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| IEB-85-003, IEB-85-3, SBN-1052, NUDOCS 8609110374 | |
| Download: ML20209E880 (3) | |
Text
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a Gec.ge S. Thomas Vice PiersidentJhictect Prcduction May 15, 1986 Public Service of New Hampshire SBN-1052 T.F. B4.2.5 N;w Hampshire Yankee Division c
Region I
! United States Nuclear Regulatory Commission
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Office of Inspection and Enforcement 631 Park Avenue King of Prussia, Pennsylvania 19406 i,
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Attention:
Dr. Thomas E. Murley, Jr., Regional Administrator
References:
(a) Construction Permits CPPR-135 and CPPR-136, Docket Nos. 50-443 and 50-444 f
(b)
IE Bulletin 85-03 " Motor-Operated Valve Common Mode Failures During Plant Transients Due To Improper Switch Settings" dated November 15, 1985
Subject:
Response to IE Bulletin 85-03
Dear Sir:
In response to the request for information in IE Bulletin 85-03, Reference (b), enclosed for your review is information applicable to Seabrook Station.
Very truly yours,
/C George S. Thomas Enclosure 4
cc:
ASLB Service List NRC Document Control Desk STATE OF NEW HAMPSHIRE Rockingham, ss.
May 15, 1986 Then personally appeared before me, the above-named George S. Thomas who, being duly sworn, did state that he is Vice President - Nuclear Production cf Public Service Company of New Hampshire, that he is duly authorized to execute and file the foregoing information in the name and on the behalf of Public
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Service Company of New Hampshire, and that the statements therein are true to the best of his knowledge and belief.
l IQ IGNATED OBICIEAL Ow.&, b S$,w
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Beverly E. Qf(loway, Notarv Public l
My Commission Expires: Mar 2 6,1990 1 \\
Certified ByS4/h/ (, //
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8609110374 860515
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PDR ADOCK 05000443
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'I 2868135640 i
U.S. Nuclear Regulat0ry Comissicn S# 3 Offica of Inspecticns & Enforcement June 13, 1986
.g Page Two 101080 As a result of one or more springs failing the effect on valve operation could be one or all of the following:
- 1) Slower closing speed in the normal forward flow direction.
This will be a minimal change given the fact that steam flow normally assists closure and a speed control dashpot is provided on BWR MSIV's to adjust the closing speed.--
2)
Increased difficulty to pass low pressure seat leakage test (LLRT) in BWR units only.
- 3) Valve closure in the reverse flow direction in PWR units could be affected since the springs alone provide the only external closing assistance.
Internal closing assistance is provided by the use of a pilot poppet design in these valves.
(v) A&M was advised verbally on June 6, 1986 by the spring manufacturer that the cause of the spring failure at Fermi was quench cracking.
Laboratory metallographic examination of the failed spring has verified this conclusion.
(vi) As stated in the reference letter springs from this same manufacturer were supplied on MSIV's manufactured by Atwood & Morrill on both PWR and BWR nuclear plants in the U.S.
The list of plants forwarded with the reference letter is again forwarded herewith for information.
(vii) We recomend at the first available opportunity the external closing springs on all MSIV's be magnetic particle inspected.
A Duer recomend inspection procedure is attached for infor-mation.
The springs should be cleaned by blasting, if required, prior to examination.
(viii)
Information and advice relative to the spring failure has been or will be given to the plants shown on the previously mentioned list.
In addition, we have been in contact with General Electric ~,
Nuclear Energy Business Operations, San Jose, CA on this failure.
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1 U.S. Nucicar Regulatory CMunission Office cf Inspections & Enforcement M 6135640-
H.3 June 13, 1986 V
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Our records indicate this is the first case of bro A&M MSIV's.
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for many years and it is our opinion there is eveT n springs on believe they will continue to do so.
ry reason to We hope the above information is satisfactory Please advise if you require additional informati
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on.
Very truly yours, e
AT00DF/MORRLL
,, INC.
24
.N. Sh'ields Vice President. Engineering SNS/ dab enclosures 1
Cc:
W. Pentland - A&M P.E. Stiff - A&M A.H. Webber - A&M F.W. Wilson - A&M i
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