ML17261B069

Discusses Testing Frequency for Insp of Incore Neutron Monitoring Sys Thimble Tubes,Per NRC Bulletin 88-009.Thimble Tube Indicating Greatest Wear Recently Repositioned in Effort to Minimize Future Wear

ML17261B069
Person / Time
Site:	Ginna
Issue date:	06/01/1990
From:	MECREDY R C ROCHESTER GAS & ELECTRIC CORP.
To:	JOHNSON A R NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM), Office of Nuclear Reactor Regulation
References
IEB-88-009, IEB-88-9, NUDOCS 9006080186
Download: ML17261B069 (3)

Text

ACCELERATED DTRIBUTION DEMONS~TION SYSTEMREGULATORY INFORMATION DISTRIBUTION SYSTEM(RIDS)ACCESSION NBR:9006080186

'OC.DATE:

90/06/01NOTARIZED:

YESDOCKETÃ"FACIL:50-244 RobertEmmetGinnaNuclearPlant,Unit1,Rochester G05000244AUTH.NAMEAUTHORAFFILIATION MECREDY,R.C.

Rochester Gas&ElectricCorp.RECIP.NAME RECIPIENT AFFILIATION JOHNSON,A.R.

ProjectDirectorate I-3

SUBJECT:

Discusses testingfrequency forinspofincoreneutronmonitoring systhimbletubes,oer Bulletin88-009.DISTRIBUTION CODE:IEISDCOPIESRECEIVED:LTR JENCL0SIZE:TITLE:Bulletin88-09-ThimbleTubeThinningznWestinghouse ReactorsNOTES:License Expdateinaccordance with10CFR2,2.109(9/19/72).

05000244RECIPIENT IDCODE/NAME PD1-3LAJOHNSON,A COPIESLTTRECLRECIPIENT IDCODE/NAME PD1-3PDCOPIESLTTRENCLINTERNAL:

AEOD/DOANRRBUCKLEY,B NRRRAMSEY,JRGN1FILE01EXTERNAL:

LPDRNSICAEOD/DSPNRRHOU,SGNRCPDR02~VVVS7S~~NOTETOALL"RIDS"RECIPIENTS:

PLEASEHELPUSTOREDUCEWASTE!CONTACTTHEDOCUMENTCONTROLDESK,ROOMP1-37(EXT.20079)TOELIMINATE YOURNAMEFROMDISTRIBUTION LISTSFORDOCUMENTS YOUDON'TNEED!TOTALNUMBEROFCOPIESREQUIRED:

LTTR13ENCL ROCHESTER GASANDELECTRICCORPORATION i89EASTAVENuE.ROCHESTER,

'N,Y.14649.0001 June1,1990C%%"U.S.NuclearRegulatory Commission DocumentControlDeskAttn:AllenR.JohnsonProjectDirectorate I-3Washington, D.C.20555

Subject:

NRCBulletinNo.88-09:ThimbleTubeThinninginWestinghouse ReactorsR.E.GinnaNuclearPowerPlantDocketNo.50-244

DearMr.Johnson,

PerourletterofJune6,1989,Rochester GasandElectricCorporation agreedtoprovideanappropriate testingfrequency forinspection ofincoreneutronmonitoring systemthimbletubesasrequiredbyNRCBulletin88-09.RG6Ehasconducted threetestsofthesubjectthimbletubes(February 1988,May1989,andApril1990)usinganEddyCurrenttestingprocedure andanacceptance criterion of65%through-wall wearasdescribed intheJune6letter.Allthimbletubeshavebeeninspected andmeetthiscriteriawiththegreatestpositiveincreaseinthrough-wall wearmeasuredtobe10%betweenanytwoconsecutive years(i.e.,1988and1989,and1989and1990)andondifferent thimbletubes.Onlyonethimbletubecurrently indicates through-wall weargreaterthan50%withthenextgreatestwearmeasuredtobelessthan25%.Thethimbletubeindicating thegreatestwearwasrecentlyrepositioned inanefforttominimizeitsfuturewear.Asaresultofthesethreetests,RGGEhasdetermined thatatestingfrequency ofonceeveryotherrefueling outage(i.e.,onceeverytwoyears)isappropriate forthimbletubeinspections whenthepreviousinspection indicates lessthan45%through-wall intheweararea.Thimbletubeswithgreaterthan45%through-wall, butlessthan55%inthewearareawillbeinspected

annually, unlessthrough-wall wearhasnotchangedbetweentheprevioustwotests.Inthisinstance, thethimbletubewillbeinspected everyotherrefueling outage..Appropriate corrective actionwillbeperformed ifathimbletubeexceeds55%through-wall intheweararea.Theabovetestingfrequencies weredetermined as'follows.

Applyingthemaximumwearrateof10%toasinglethimbletubeinitially measuring lessthan45%through-wall wearwouldnotresultintheacceptance criterion of65%beingexceededoveratwoyearperiod.Applyingthissamewearrate,toasinglethimbletubewiththrough-wallwearrangingbetween45%and55%foroneyearwillalsonotresultintheacceptance criterion of65%beingexceeded.

The65%acceptance criteriaincludesnecessary instrumentation uncertainty considerations.

Pmgz'<QQI~QPQ fel+'??QQ&QiF'DRADOCKQ'QQQ24+'~ywon.~~~~

QF'DCi(p Thesetestingfrequencies maybechangedifthemaximumwearratebetweentestsindicateeitherexcessive orsignificantly lessthrough-wall wear.TheNRCwillbenotifieduponanychangeintestingfrequency.

RobertC.MecreDivisionManagerNuclearProduction Subscribed andsworntobeforemeonthis1stdayofJune,1990NotaryPublicSAMUELH.BAOWNENTARYPUBLlC,StatsolNowYetrationNo.49>7041QttsinMonoeCy.IWayneMyConstsssan spiesDeo.28,19MDFN120xc:AllenR.Johnson(MailStop14D1)ProjectDirectorate I-3Washington, D.C.20555U.S.NuclearRegulatory Commission RegionI475Allendale RoadKingofPrussia,PA19406GinnaSeniorResidentInspector