ML20010E716

LER 81-022/03L-0:on 810801,MSIV-80D Failed to Close When Control Switch Was Placed in Closed Position.Caused by Foreign Particle Lodged in Spool Valve,Preventing Air from Operating Main Piston.Msiv Fully Stroked

ML20010E716
Person / Time
Site:	Vermont Yankee File:NorthStar Vermont Yankee icon.png
Issue date:	08/28/1981
From:	Murphy W VERMONT YANKEE NUCLEAR POWER CORP.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML20010E715	List: ML20010E714 ML20010E716
References
LER-81-022-03L, LER-81-22-3L, NUDOCS 8109080192
Download: ML20010E716 (2)

Text

CFO +366 U. S. NUCLE AR R EGULATOQY COMMISSION LICENSEE EVENT REPORT LER 81-22/3L CONTROL BLOCct: l I I l l I lh (PLEASE PRINT OR TYPE ALL REQUIRED INFOCMATION) 1 6 IO Iii8 l9 VI TlLICENSEE 7

VI YI SI 1l@lo Io l- 10 I oLICENSE CODE 14 15 l o lNVMSER ol0l I o I o25 l@l26 6 lUCENSE 3 l 3 TYPE] il 3l@l Jo l

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60 61 DCCKET NUM8 ER 68 69 EVENT DATE 14 75 I I I REPORT DATE l l 80 I@

EVENT DESCRIPTION AND PROB ABLE CONSEQUENCES h io ;g l While performing MSlv surveillance, MSIV-80D failed to closc. when it's control l 1o tal l switch was placed in the Closed position. This failure to close is contrary to l l o 141 1 T.S. Sec. 3.7.D.l. The valve did close upon actuation of the slow close switch. l Io Is! l The redundant valve in this line (MSIV-86D) was successfully tested. There were I l o (6 ] l no consenuences to the puhtic health and safety as a resul t of this event. _1 lo l7l l Similar occurrences have been reported to the cormiission within the past 5 years I t o tal I a s LER 78-4 and 77-35. I 7 8 9 80 E COCE SUBC E COMPONENT CODE SL B ODE SU E loisi I cl DI @ U @ U @ l v l Al L I VI of Pl@ [D_ j h l,7_,l @

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, SEQUENTIAL OCCURAENCE REPORT REVISION lea EVENTVEAR R EPORT NO. CODE TYPE N O.

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33 34 35 36 3J 43 41 42 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS h li lo l l Each MSIV is actuated by two pilot valves. Inonerability of MSIV-8oD was I g_ a ttributed to a foreign particle lodged in the spool valve which prevented l

,,,7, l air from operating the main piston. The MSIV was fully stroked satisfactorily l gl six times. During the next outage, the pilot valve will be inspected to I gl determine if any further corrective action is necessary. I 7 8 9 80 ST S  % POWER OTHER STATUS dis O Y DISCOVERY 0ESCRIPTION I1 15 l 1 Flh lo l 4 l 5 lhl NA l lBlhlSurveillanceTest l ACTivtTY CO TENT RELE ASED OP RELEASE AMOUNT OP ACTIVITY LOCATION OP RELEASE li is i LzJ @ Lzj@l 10 m

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7 9 9 11 PERSONNEL EXPOSURES NUMBER TYPE DESCRIPTION .*

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11 80 LOSS OP OR DAMAGE TO PACILITY TYPE DESCRIPTION NA l I i 19' I'I z l@l' 8 8109080192 810828 N R C US E ON L',

iS$u E o'ESCRiPfiON@ PDR ADOCK 05000271 ,

l:loI 7 8 3 hl 10 NA S PDR 68 63 llll lllt!lll{

SO 3 NAME OF PREPARER Warren P_ Mitrohv PHONE: (R07I 757-7711 h

, V VTVYS1 05900271 LER 81-22 l

EVENT DESCRIPTION AND PROBABLE CONSEQUENCES While performing Main Steam Isolation Valve (MSIV) surveillance, MSIV-80D failed to indicate closed af ter it's control switch was placed in the Closed position. Technical Specifications Section 3.7.D.1 requires the MSIV's to be operable during reactor power operation conditions. The valve did close upon actuation of the " slow close" switch. The redundant isolation valve in this line (MSIV-86D) was positioned in the isolated mode as required by .

Technical Specifications Section 3.7.D.2. As a result of this event, there were no consequences to the public health and safety. Similar occurrences have been reported to the commission within the past five years as LER 78-4 and 77-35.

CAUSE DESCRIPTION AND CORRECTIVE ACTION Each Main Steam Isolation Valve is actuated by two three-way solenoid operated pilot valves. Inoperability of MSIV-80D was attributed to a foreign particle lodged in the sliding spool area of the pilot valve which prevented air from being redirected to the opposite side of the main valve piston operator thus preventing the valve from c.'osing. Af ter the valve had been closed by actuating the " slow close" switth, it was normally full stroked satisfactorily six times. Both Main Steam Isolation Valves, MSIV-S0D and 86 D, will be full stroke exercised, in approximately one month from the event date,:to verify continued operability.- .Also, during the next scheduled

. outage of sufficient duration, the pilot valve will be removed and inspected to determine if any further corrective action is.necessary.

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