ML20090E235

AO 73-12-1:on 731201,during Surveillance Test,Magnetrol Switch 352624 in Scram Dump Vol Level Sys Failed to Operate. Caused by Oxidized Mercury in Bulb of Switch.Mercury Bulb Replaced

ML20090E235
Person / Time
Site:	Nine Mile Point
Issue date:	12/04/1973
From:	Perkins T NIAGARA MOHAWK POWER CORP.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML20090E233	List: ML20090E231 ML20090E235
References
AO-73-12-1, NUDOCS 8303140169
Download: ML20090E235 (2)

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TO: HR. JAMES P. O'REILLY AOP. 73-12 1 ON DECDillER 1,1973 AT 1300 Il0URS A MGNUTROL SWITCil #352624 IN THE SCP.AM DUMP YOLUME LEVEL FAILE0 '10 OPERATE DukING SilRVEILIANCE TEST 1tlG AT NINE MII.E POThT hTCl. EAR STATION UNIT 1. tilts IS AN ABNORMAL OCCURRENCE l PERSUAhT TO TECfD!ICAL SPECIFICATIONS 1.13 b.

THE 11 NIT WAS OPERATING NORMALLY AT 1272 MWt, (920 MWe) WTill ALL PLAhT d SYSTEMS NORMAL. ROUTINE SURVEILLANCE TESTING WAS IN PROGRESS. THE SCRAM i IXIMP VOLUME LINEL SWITCilES (37 GAI..) CAUSE A REACTOR SCRAM IN A 1 OUT 1

2 TWICE LOGIC. RDOSC FATLED TO CAUSE Ti!E REQUIRED ACTUATION OF #12

' RIP OIANNEL. Tile REHATNING THREE INSTRUMENTS IN T111S SYSTEM PERFORMED AS y REQUIRED, {

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INVESTICATION REVEALED THAT 1HE MERCURY IN THE HERCURY BULB HAD

. lI, OXfD12ED T.OCKING Tile MERCURY IN ONE POSITION. Tile SWITOI CARRIAGE IIAD l

HOVED AS REQ,UIRED. A PIN liOLE IN T112 BULB ALLOWED AIR IN EhTRY AND j OXIDATIONOFMERbfRYIIADOCCllRRED. Ti!E MERCIIRY B!If.B WAS REPLACED AND T1!E l

SWTTCll FUNCTIONED NORMALLY ON TEST.

SDiCE 'IEE REDUNDANT COMPONENT WAS FULLY OPERABLE A SCRAM WOULD HAVE BEEN PRODUCED IF REQUIRED AND THEREFORE NO HAZARD WAS PRESEhTED TO lilE PLANT Ok THE GENERAL PUBLIC. 'lHIS IS THE FIkST PAILukE OF THIS RATURE.

VERY TRULY YOURS, B303140169 731210 k T110m s .1, PERr.rNS s RADOCK05000$ STATION SUPERINTENDEhT NINE HILE POIhT hTCLEAR STATION s /! 1 i

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MEMO ROUTE SLIP I 5 * * *** *

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To cNam. .nd on.o ETins nManns NIAGARA MOHAWK R0 Chief, FS6E NINE MILE POINT NUCLEAR STATION R0: LIQ (5)

R0 Files DATE DN-50-220 Central Mail & Files Regulatory Standards (3) AO 73-12-1 TO (Name and unst) trEUALS REMARK $

Directorate of The above abnormal occurrence is forwarded for Licensing (13)

OGC un information. Distribution will be made Regional Directors (R0 II, III, IV) .. by this office to the PDR, Local PDR, TO (Nam. and unit) areTIALS REMARIJ NSIC, DTIE, and State Representatives, un i

FR (Ps.ma and unit) REMARKS

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ET}s J. Brunner -

Region I PHONE NC. DATE 8-337-1246 12/4/73 USE OTHER SIDE FOR ADDIThW4AL REMARKS cro nett 0 - 449een e

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