ML17328A584

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LER 90-002-00:on 900108,two MSIVs Exhibited Closing Time in Excess of Tech Spec 3.7.1.5 Limit of 5 S.On 900109 & 10, Confirmed That Excessive Condensation Collected on Vent Side.Caused by Inadequate insulation.W/900209 Ltr
ML17328A584
Person / Time
Site: Cook American Electric Power icon.png
Issue date: 02/09/1990
From: BLIND A A, DROSTE J B
INDIANA MICHIGAN POWER CO. (FORMERLY INDIANA & MICHIG
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-90-002, LER-90-2, NUDOCS 9002280017
Download: ML17328A584 (12)


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ACCELERATEDD1BUTl0NDE}d04STATIONSYSI'EMREGULATOINFORMATIONDISTRIBUTIONSYSTEM(RIDS)ACCESSIONNBR:9002280017'OC.DATE:90/02/09NOTARIZED:NODOCKETIFACIL:50-316DonaldC.CookNuclearPowerPlant,Unit2,Indiana&05000316AUTH.NAME'UTHORAFFILiATIONDROSTE,J.B.IndianaMichiganPowerCo.(formerlyIndiana&MichiganEleBLIND,A.A.IndianaMichiganPowerCo.(formerlyIndiana&MichiganEleRECIP.NAMERECIPIENTAFFILIATION

SUBJECT:

LER90-002-00:on900110,MSIVinoperabilityduetocondensateaccumulationonventsideofoperatingpiston.W/8ltr.DZSTRZBOTZONCODE:ZE22TCOPZESRECEZVED:LTRjENCL[SZSE:TITLE:50.73/50.9LicenseeEventReport(LER),IncidentiRpt,etc.NOTES:RECIPIENTXDCODE/NAMEPD3-1LAGIITTER,J.INTERNAL:ACNWAEOD/DSP/TPABDEDRONRR/DET/EMEB9H3NRR/DLPQ/LHFB11NRR/DOEA/OEABllNRR/DST/SELB8DNRRQ~R/LB8DlEGFXL02RGN3FILE01COPIESLTTRENCL111122111111111111111111~RECIPIENTIDCODE/NAMEPD3-1PDAEOD/DOAAEOD/ROAB/DSPNRR/DET/ECMB9HNRR/DET/ESGB8DNRR/DLPQ/LPEB10NRR/DREP/PRPB11NRR/DST/SICB7ENRR/DST/SRXB8ERES/DSIR/EIBCOPIESLTTRENCL11112211111122111111hDS44111111NOIR'IOALL'RICS"KXIPIBGSEXTERNALEG&GWILLIAMSESLPDRNSICMAYS,GNUDOCSFULLTXTLSTLOBBYWARDNRCPDRNSICMURPHYgGA111111RIDSDDSPIZASEHELPUSIOREVXZ%RKE!CGKPACT'IHEDOCXMWZCOWEDDESK-,LXSTSFORDOCUMEMISYOUDC%ITNEED!FULLTEXTCONVERSIONREQUIREDTOTALNUMBEROFCOPXESREQUIRED:LTTR35ENCI35 IndianaMichiganPowerCompanyCookNuclearPlantP.O.Box"58.Bndgman.Ml'91066164655901INDIANANICHIGANPOWERFebruary9,1990UnitedStatesNuclearRegulatoryCommission.DocumentControlDeskRockville,Maryland20852OperatingLicenseDPR-74DocketNo.50-316DocumentControlManager:Inaccordance,withthecriteriaestablishedby10CFR50.73entitledLicenseeEvent,ReortinSystem,thefollowingreportisbeingsubmitted:90-002-00Sincerely,A.A.BlindPlantManagerAAB:clwAttachmentccD.H.Williams,Jr.A.B.Davis,RegionIIIM.P.AlexichP.A.BarrettJ.E.BorggrenR.F.KroegerNRCResidentInspectorJ.G.Giitter,NRCR.C.CallenG.Charnoff,Esg.DottieSherman,ANILibraryD.HahnINPOS.J.Brewer/B.P.Lauzau@00224<00/7+00209PDRADOCI0<00031bPDr:

NRCFORM366(689)U.S.NUCLEARREGULATORYCOMMISSIONLICENSEEEVENTREPORTILER)APPROVEDOMBNO.31504104EXPIRES:4/30/92ESTIMATEDBURDENPERRESPONSETOCOMPLYWTHTHISINFORMATIONCOLLFCTIONREQUEST:50.0HRS,FORWARDCOMMENTSAEGARDINGBURDENESTIMATETOTHERECORDSANDREPORTSMANAGEMENTBRANCH(P630),V.S.NUCLEARREGULATOAYCOMMISSION,WASHINGTON,DC20555.ANDTOTHEPAPERWORKREDUCTIONPROJECT(31500104).OFFICEOFMANAGEMENTANDBUDGET,WASHINGTON,OC20503.FACILITYNAME(I)D.C.CookPlant-Unit2DOCKETNUMBER(2)PAE050003161OF1"PTITLE<<IMainSteamIsolation"ValveInoperaiity-DuetoConensateAccumulationonVentSideofOperatingPistonEVENTDATK(5)LERNUMBER(41REPORTDATE,(7)OTHERFACILI'TIESINVOLVED(4)MONTHDAYYEARYEARSEQUENTIALNVMSEtlreIIEVISIONNVMSEIIMONTHOAYYEARFACILITYNAMESCookPlant-Unit1DOCKETNUMBER(SI05000315011090900020002099005000OPERATINGMODEIS)3POWERLEVELppp20.402(SI20.4051~I(lI(ll20406(~)(1)(lll20.405(~I(II(IIl)20.406(el(II(NI20.405(~l(l)(vlX20.405(c)50.34(cl(lI50.34(cl(2)60.73(el(2)(I)60.73(e)(2)(S)50.73(el(2)Ill))LICENSEECONTACTFOATHISLER(12I50.73(el(2)(lv)50.73(el(2llv)'0.73(el(2)(vSI.50.73lel(2)(vSI)(AI'0.73(e)12)(el)II(5)50,73(~I(2I(eITHISREPORTISSUBMITTEDPURSUANTT0THEREQUIREMENTSOF10CFR('):(Cntceontormortotrntlottowrnd)(1173.7)(S)73.71(c)OTHKR(SptcrryinAprtrtctStrowtndinTerI,HRCForm3ddAINAMEJ.B.Droste--TechnicalEngineeringSuperintendentAREACODETELEPHONENUMBER616465-5901COMPLETEONE(.INEFOAEACHCOMPONENTFAILUREDKSCRIBEDINTHISREPORT(13)CAUSESYSTEM\'COMPONENTMANUFACTVREREPORTABLETONPRDSCAUSESYSTEMCOMPONENTMANUFACTVRERBSBVTVX999.Y'Prr.,~4.NXrr.r..SUPPLEMENTALREPORTEXPECTED(14)YEStttytr,comprtrtFXPECFEDSVSMISSIONDAFEIXABS'TAACTtLimrtrott00Iptctt,r,t.,tpprorimtttiytrttttntin(littoterryptwrirttntmttt(14)FXPECTED'UbMISSIONDATE(ISIMONTHDAYYEAROnJanuary8,1990withUnit2inMode3-(HotStandby)surveillancetestingoftheMainSteamIsolationValves(MSIV's)wasconducted.TwoMSIV'sexhibitedaclosingtimeinexcessoftheTechnicalSpecification3.7.1.5limitoffiveseconds.Thiscondit'ionisbelieved.tohave,existedduringpoweroperation.AdditionalMSIVtestingonJanuary9,and10,1990confirmedthatexcessivecondensationwascollectingontheventsideoftheMSIVoperatingpiston.Whenthedumpvalveswereopenedtovent-offsteamfromtheMSIVoperatingpiston,theaccumulatedcondensatewouldflashtosteamandresultinincreasedMSIVclosuretimes.FollowinganefforttoblowouttheMSIVcondensatedraintubes,aseriesoftestswereperformedatvarioustimeintervals.todetermineifthecondensateproblemhadbeenresolvedandverifyMSIVoperability.Withthefailureof2-MRV-220onJanuary11,1990,at0916hours,itwasevidentthatthecondensatep'roblemwasstillpresent.AllMSIV'sweredeclaredinoperable.andanUnusualEventwasdeclared.AcooldowntoMode5(ColdShutdown)wasstarted.RepairactivitiesincludeddisassemblyoftheMSIV'stoenlargethecondensatedraintubeportandtheequalizingsteamnipple.AdditionalinsulationwasplacedontheMSIV's,ventpipingandvalves.NRCForm366(669)

NRCFORM366A(6J)9)V.S.NUCLEARREGULATORYCOMMISSIONLICENSEEEVENTREPORT(LER)TEXTCONTINUATION"APPROVEDOMBNO.31500)OSEXPIRES:S/30/92ESTIMATEDBURDENPERRESPONSETOCOMPLYWTHTHISINFORMATIONCOLLECTIONREQUEST:50.0HRS.FORWARDCOMMENTSREGARDINGBURDENESTIMATETOTHERECORDSANDREPORTSMANAGEMENTBRANCH(P430).U.S.NUCLEARREGULATORYCOMMISSION,WASHINGTON,OC20555.ANDTOTHEPAPFRWORKREDUCTIONPROJECT(3(500104).OFFICEOFMANAGEMENTANDBUDGET.WASHINGTON,OC20503.FACILITYNAME(1)DOCKETNUMBER(2)YEARLERNUMBER(6)SEQVENTIALNVMEERREVISIONNVMSERPAGE(3)-D.C.CookPlant-Unit2TEXT///morespeceiereqvirN/.Irse~HRC%%drm3(SEA's/(12)osooo316900020000CONDITIONSPRIORTOOCCURRENCEUnit2inMode3(HotStandby).DESCRIPTIONOFEVENTOnJanuary8,1990,surveillancetestingoftheMainSteamIsolationValves(MSIV'-s)(EIIS/SB-ISV)wasconducted.TwooftheMSIV'sexhibitedaclosingtimeinexcessoftheTechnicalSpecification3.7.1.5limitoffiveseconds.FollowingeachMSIVfailure,theMSIVwasdeclaredinoperableandimmediatelyretested.InbothcasestheretestdemonstratedthevalveclosedwithintheTechnicalSpecificationtimelimitandthe,MSIVwasdeclaredoperable.AdditionaltestswereconductedonJanuary9,1990.Asubstantialamountofwaterwasobservedtoflashoutofthedumpvalve(EIIS/SB-VTV)ventstacksduringthefirst'estofeachMSIV.ThreeMSIV's.exhibitedaclosingtimeinexcessoftheTechnicalSpecification3.7.1.5limitoffiveseconds.FollowingeachMSIVfailure,theMSIVwasdeclaredinoperableandretested.In-eachcasetheretestdemonstratedthevalveclosedwithintheTechnicalSpecificationtimelimitandtheMSIV'sweredeclaredoperable.(Seeattachedtesttable).TheJanuary9,1990testingverifiedthatenoughcondensationcouldaccumulateontheventsideofthepistonwithina24hourperiodto'enderthevalveinoperable.Unit2washeldinMode3tofurtherdiagnosetherootcauseofthisissue.5Sec.6Sec.TIMECONTROLROOMSWITCHACTUATIONTOLIGHTMSIVSTEMTRAVELOnJanuary10,'1990,aseriesofdiagnostictestswereperformedtodeterminetheextentthatcondensatewithintheMSIVoperatingcylindervolumecouldaffectMSIVstroketime.Astripchartwasusedtorecordpressurewithinthevolumeasafunctionoftime.Closuretimewasmeasuredinthecontrolroom,measuringthetimefromthedumpvalveswitchactuationuntiltheMSIVvalvelightindicatedthevalvewasclosed.MSIVstemtraveltimewasmeasuredlocally.Thefollowingtime.lineissimilartoeachMSIVtestedandrepresentstypicalcircumstancesexperiencedbyallMSIV's.01Sec:2Sec.3Sec.4Sec.FLASHINGrNRCForm366A(669)

NRCFORM355A~)549)U.S.NUCLKARREGULATORYCOIAMISSIONLICENSEEEVENTREPORTILER)TEXT.CONTINUATIONAPPROVEDOMSNO.31504104EXPIRES.4/30/92ESTIMATEDbURDENPERAESPONSETOCOMPLYWTHTHISINFORMATIONCOLLECTIONREQUEST)500HRS.FORWARDCOMMENTSREGARDINGSURDENESTIMATETOTHERECORDSANDREPORTSMANAGEMENTSRANCHIP430).U.S.NUCLEARREGULATORYCOMMISSION.WASHINGTON.OC20555,ANDTO1HEPAPERWORKREDUCTIONPAO/ECT13150410i)iOFFICEOFMANAGEMENTANDSUDQET,WASHINGTON.DC20503.FACILITYNAMEl1)DOCXETNUMSER(21LERNUMSERIS)~AGE13)D,C.CookPlant-Unit2TEXT///verePPPCP)I/Pquia/,MPP//I/bbP//YRC%%dnt)30SA'P/)IT)osooo316YEAR9.0SEQUENTIALNUMKll@002.'-REVISIONNUM9II000OF10LocalobservationverifiedsubstantialquantitiesofwaterandsteambeingdischargedfromtheventstackfromT0untilMSIVstemtravelbegan.TwooftheMSIV'sexhibitedaclosingtimeinexcessoftheTechnicalSpecification3.7.1.5limitoffiveseconds.'FollowingeachMSIVfailure,theMSIVwasdeclaredinoperableandretested.IneachcasetheretestwasanacceptablevalueandtheMSIVwasdeclaredoperable(seeattachedtesttable).TheActionRequirementsofTechnicalSpecification3.7.1.5werefulfilledatalltimesforModes2and3.WhenanMSIVfai'lureoccurred,animmediateretestdemonstratedthatthevalvewasoperable.OnJanuary10,1990,itwasrealizedthatthefailureswhichoccurredonJanuary8,1990,werebelievedtohaveexistedduringpoweroperation.NotificationtotheNRCwasmadeonJanuary10,1990,reportingthatwewereoutsidetheplants'esignbasesonJanuary-8,1990.Atthetimethisnotificationwasmade,theMISV'swereoperableperTechnicalSpecificationActionRequirementsforModes2and3operation.TheMSIV'swereoperablesincethetestingresultedinexpellingthecondensate,fromtheventsideofthevalve'soperatingpiston.TheMSIV'swouldremainoperableaslongasthevalveswerecycledfrequentlyenoughtdpreventexcessiveamountsofcondensatefromcollectingontopoftheoperatingpiston.~TheMSIVtestingconfirmedthattheslower,mainsteamstopvalvestroketimesweresymptomsofanunacceptab1equantityofcondensateaccumulatingintheuppervalvevolume;Whenadumpvalveisopenedthecondensateflashestosteam'thiscausesincreasedventingtimeduetodelayingthedevelopmentofsufficientDelta-PacrosstheMSIVpiston,toclosetheMSIV's.A"logicalhypothesiswasformulatedthatcondensatewas'notdrainingdownintothelowervolumethroughthedraintube(seeattacheddrawings)fastenoughtopreventaccumulationintheuppervolume.Actingunderthepremisethatthisflowpathwasinsomewayrestricted,possiblyduetomineraldepositsplatingoutontheinsidediameterofthedraintube,itwasdecidedtoattempttoblow-outthisdraintube.Aprocesswasdevisedtoremove(blow-out)anypossiblerestrictionslocatedwithineachMSIVdraintubes.ThiswasaccomplishedbymaintainingtheMSIVinitsclosedpositionandforapproximatelyonehourwiththedumpvalvesopen.In'doingso,mainsteamwascapableofforcingitswaypasttheparallelclosuredisc,throughthedraintubeintotheuppervolume,andexhaustedouttheventstack.,Itwashopedthatthisexhaustedsteamwouldbeofsufficientvelocitytocarryawayanyrestrictivematerial.NACForm395A1509)

NRCFORMSSSAISeS)tU.S.NUCLEAAREGULATORYCOMMISSIONPLICENSEEEVENTREPORTILER)TEXTCONTINUATIONAPPAOVEDOMSNO.S)504104E)IPIRES:S/20/02ESTIMATEDBURDENPERRESPONSETOCOMPLYWTHTHISINFORMATIONCOLLECTIONREOUESTI50.0HRS.FORWARDCOMMENTSREGARDINGBURDENESTIMATETOTHERECORDSANDREPOATSMANAGEMENTBRANCHIPe30).U.S.NUCLEARREGULATORYCOMMISSION,WASHINGTON,DC20555,ANDTOTHEPAPERWORKREDUCTIONPRO/ECT121504)OS).OFFICEOFMANAGEMENTANDBUDGET,WASHINGTON,OC2050KIrACILITYNAME)1)DOCKETNUMBER)2)LERNUMBERIS)PAGEIS)D.C.CookPlant-Unit2TEXTlllmore<<eoe/ereevrw/,ow//r/orO///RC%%dnIISSSAB/)12)osooo'316YEAR4g90sEovsNTIALoENVMSSR002IISVISIONNVMSN0004.OF10Additionaltestingwasperformedtodetermineifthemaintenanceactionwassuccessfulandensure.MSIVoperability.Thisseriesoftestshadstaggered'estintervalstoensureMSIVoperabilityw'asmaintained.OnJanuary11,1990,at0916hours,2-MRV-220exceededtheallowedclosingtime.AnUnusualEventwasdeclaredasallfour(4)MSIV'sweredeclaredinoperablecausingaTechnicalSpecification3.0.3shutdown.Thiswasclassifiedasa'One-Hour,ReportableEventandNRCnotificationwasmadeat0930hours.AcooldowntoMode5(ColdShutdown)wascommenced.CAUSEOFEVENTInvestigationrevealedthatthefailureof'heMSIV'swascausedbyexcessivecondensateaccumulationontheventsideoftheMSIV'operatingpiston.Theexcessivecondensateaccumulationwasaresultofthefollowingcontributingfactors:InsulationLessthanCurrentDesin-InsulationonMSIV,theventpipingandassociatedvalveswaslessthancurrentdesignspecifications.TheinsufficientinsulationresultedinincreasedcondensationratesintheMSIV.2.DumValveSeatLeakaeThequantityofcondensatethatcancollectisrelatedtothemassofsaturatedsteampermittedtoentertheupperequalizingsteamvolume.Whensteamisallowedtoescapethisvolume,itwillbereplacedbyadditionalsaturatedsteamwhichincreasestheDelta-Pandpreventsdrainage.3.MSIVActuatorDesinThecombinedeffectsofoneandtwoaboveresultedinincreasedcondensationrates,developinggreaterDelta-Pacrosstheoperatingpistonthanassumedbydesignduringnormaloperation(MSIV'sinsteady-stateopenposition).Therateatwhichcondensatecanflowdownfromtheuppervolumethroughthedraintubeislimitedbythediameterofthedraintubeportholes.Condensatewillaccumulatewithintheupperequalizingvolumeifitcannotbedrainedfasterthanitforms.Ifthesteamnippleisinsufficientlysized,aDelta-Pwillexistacrossthepistonrestrictingcondensatedrainage.NRCFomrSSSAISeS)

NRCFORM355AISJ)91US.NUCLEARREGULATORYCOMMISSIONLICENSEEEVENTREPORT(LER)TEXTCONTINUATIONAPPROVEOOM8NO,3150010>>EXPIRES:>>/30/92ESTIMATED8UROENPERRESPONSETOCOMPLYWTHTHISINFORMATIONCOLLECTIONREOUESTI50.0HRS.FORWARDCOMMENTSREGARDING8URDENESTIMATETOTHERECORDSANDREPORTSMANAGEMENTSRANCHIP430).U.S.NUCLEARsREGULATORYCOMMISSION,WASHINGTON,DC20555,ANDTO1HEPAPERWORKREDUCTIONPROJECT13150010l).OFFICEOFMANAGEMENTAND8UDGET,WASHINGTON,DC20503.FACILITYNAME111D.C.CookPlant-Unit2TEXT////>>P/>><<eC>>/1I>>qvnd,uJePI/P5/>>/HJICfcnn38559/)12)DOCKETNUMSER12)os0oo316YEAR90LERNUMSER15),>>jjSEOVENTIALyg:AEVOONHVM5<<<~+HVM002-00~AGE13)050F10ANALYSES,OFEVENTInadditiontoTechnicalSpecification3.7.1.5,slowMSIVclosuretimesaffectTechnicalSpecificationitems3.3.2.1,Table3.3-5,5.h(HighSteamLineFlow-LowLowTavg),6.h(SteamLinePressureLow),and7.c(ContainmentPressure-HighHigh).Theseitemsusethevalveclosuretimeaspartoftheiroveralltimeresponserequirement.Examinationofsurveillancedatafortheseitemsshowthatitem7.c,steamlineisolationonhigh-highcontainmentpressureinsevenseconds,wouldnotbemet.ThiswasreportedtotheNRConJanuary10,1990,undertheprovisionsof10CFR50.72.b.l.ii.Basaconditionthatwasoutsideoftheplant'sdesignbasis.Theinvestigationofthisproblemhasidentifiedthattheslowerclosuretimeswerecausedbywateraccumulationonthetopofthesteampiston.Withwaterpresent,thepistonmovementisslowedasthewaterflashestosteamduringtheventingprocess.Thewater.accumulationoccursovertimeandisalsoaffectedbytheleakagepasttheMSIVdumpvalves.Oncethewaterisremovedfromthetopofthepiston,aswouldoccurduringavalvetest,.aretestconductedimmediatelythereafterwouldindicatenormalva3veactuationtimes.Aswaterwouldaccumulateduringoperation,thereisevidencethattheconditionmayhaveexistedpriortothesurveillance.Thus,itisprobabl'ethatTechnicalSpecification4.7.1.5.1wasnotmet.WestinghousehasevaluatedtheconsequencesofincreasingallapplicableTechnicalSpecificationresponsetimesbythreeseconds,andtheyhaveconcludedthattheFSARacceptancecriteriaaremetusingthelongerresponsetimes.ThemassandenergyreleasesforanoutsideofcontainmentsteamlinebreakwerecomparedwiththecurrentFSARvalues,andthe'nvironmentalqualificationoftheequipmentintheaffectedlocationshasnotbeencompromised.Thus,therehasbeennosignificantdegradationofplantsafetyasaresultoftheincreasedMSIVclosuretimes.SinceUnit1hasthesametypeofvalve,anevaluationwasalsoperformedconcerningthe'impacton.Unit1.TheevaluationconcludedthattheMSIV'son,Unit1areconsideredtobeoperableandfullysupportiveoftheChapter14accidentanalyses.Atthelastsurveillances,allTechnicalSpecificationsapplicabletosteamlineisolationweremet,andthehistoricaldataindicatenopatternofclosuretimedeterioration.Further,therecentWestinghouseanalysisshowsthatsufficientmarginexistswithMSIVclosuretimesuchthatplantsafetyisnotcompromisedifthe'systemresponsetimeisincreasedbythreeseconds.Thus,therecenteventsassociatedwiththeUnit2MSIV'sdonotcauseundueconcernwithrespecttothecontinuedsafeoperationofNRCFons355A(5891 NRCFORM344A~14e9)U.S.NUCLEARREGULATORYCOMMISSIONLICENSEEEVENTREPORTILER)TEXT.CONTINUATIONAPPROVEOOMSNOl31500)0OExpIREs:el30)92ESTIMATEDBURDENPERRESPONSETOCOMPLYWTHTHISINFORMATIONCOLLECTIONREOUEST:50.0HRS.FORWARDCOMMENTSREGARDINGBURDENESTIMATETOTHERECORDSANDREPORTSMANAGEMENTSRANCH(P430).U.S.NUCLEARREGULATORYCOMMISSION,WASHINGTON.DC20555,ANDTOTHEPAPERWORKREDUCTIONPROJECT131504)104),OFFICEOFMANAGEMENTANDSUOGET.WASHINGTON.DC20503.FACILITYNAME11)DOCKETNUMSER12)YEARLERNUMSER(4)rX<OSEQUENTIAL?P~WIIEYISIONNVMFEAi.rXNVMI'AGE13)D.C.CookPlant-Unit2TEXTNmorea>>ooJrreqond,Irreorroeo'onerHRCformSOD'e))12)osooo31690-002-0006oF10Unit1.Thisconclusionisals'obasedonthebeliefthatthepresentperformanceoftheUnit1MSIV'sdonotresultintheprobabilityorconsequencesofanaccidentbeingincreased,anynewtypeofaccidentbeingcreated,andanyTechnicalSpecificationmarginofsafetybeingreduced.CORRECTIVEACTIONSUponreachingMode5,allfourMSIV'sweredisassembledandavisualexaminationperformed.Theseexaminationsrevealedthatthedraintubeshadnotexperiencedanyphysicaldegradationthatcouldhaverestrictedthecondensateflowpath.Alldimensionswereverified.ElectricITEdeFrance(FDF)wascontactedconcerningtheirapproachatresolvingsimilarcircumstances.EDFprovidedtheirinvestigationfindingsandvalvedesignmodifications.WeimplementedtheEDFrecommendations.Afterallavailablesourcesofinformationweretechnicallyevaluated,itwasdeterminedthatallUnit2MSIV'swouldbemodifiedviaMinorModification2-Mf-079.Underthismodificationthediameterofdraintubeportholeswouldbeincreasedfrom1'/8"(0.125")to5mm(0.197")andthediameteroftheequalizingsteamnipplewouldbeincreasedfrom1/8"(0.125")'o10mm(0.394").Twoperformancerelatedfunctionswouldbeimprovedinthismanner.l.Increasingthesizeofthedraintubeportholesprovid'esalargerareatoimprovecondensateflowthroughtheactuatorpiston.2.Increasingthesizeoftheequalizingsteamnipplewillprovidealessrestrictivepathforsteamtopassupthroughthepistontomaintainequilibriumandpreventsteamfrompassingthroughthedraintubeandinhibitdrainage.ItwasalsodiscoveredatthistimethattheinsulationontheMSIV,ventpipingandassociatedvalveswaslessthanthecurrentdesignspecificationrequirements..Thiscontributedtoalargervarianceintemperature(Delta-T)resultinginmoreheattransferandincreasingthecondensationrate.Aftercompletingallmodificationsandreassemblingthe,MSIV's,SpecialProcedure2-THP.SP.MM-079wasusedtoverifyoperability.ThisprocedureincludedaseriesoftestcyclesforallMSIV'satdifferentintervalswiththeappropriateinstrumentationrequiredtomeasureandrecordallapplicableperformancevariables,specificallytherateofpressuredropintheventline.NRCForm344AI5$9)P NRCFORMSSSA(5JISIU.S.NUCLEARREGULATORYCOMMISSIONLICENSEEEVENTREPORT(LER)TEXTCONTINUATIONAPPROVEDOMSNO.S1500104EXPIRES:A/SO/52ESTIMATEDSUROENPERRESPONSETOCOMPLYWTHTHISINFORMATIONCOLLECTIONREQUEST:500HRS.FORWARDCOMMENTSREGARDINGSURDENESTIMATETOTHERECORDSANDREPORTSMANAGEMENTSRANCHIP5201.U.S.NUCLEARREGULATORYCOMMISSION,WASHINGTON.DC20555.ANDTOTHEPAPERWORKREDUCTIONPROJECT(S(5041(M).OFFICEOFMANAGEMENTANDSUDGET,WASHINGTON,OC20502,FACILITYNAME(1)DOCKETNUMSER(21YEARLERNUMSER(5)YP>',SSQVSNTIA'LNVMSllII5YISIONNVMSA~AGELSID.C.CookPlant-Unit2TEXTIIImcmapeceJIIPSw'wI,PPPaAWonVHRCRPmI~SI(12(oso0031690002I-00070F10Theacceptancecriteriausedwithin'2-THP.SP.MM-079wastwofold.First,eachfullclosurestroketimemustbewithin5secondsinaccordancewithTechnicalSpecification3.7.1.5.Second,therateofpressure,dropintheventlinemustnotchangeasthetestintervalisextendedto24hours.Thissecondcriteriawasusedtoverifynoadditionalcondensatehadaccumulatedwithintheuppersteamvolumethatcouldlengthenstroketimeanddelaystemtraveluponflashingtosteamduringtheventingprocess.Allstroketestsperformedinaccordancewith2-THP.SP.MM-079,exceptthefirsttestonMRV-210,provided.acceptableresultsandverifiedthegenericcondensateissue.hadbeenresolved;Theiniti'altestperformedonMRV-210failed.Thecorrespondingrateofpressuredropintheventlinesignatureverifiedsignificantquantitiesofcondensatestillpresent.Investigation.revealedthatTrainBDumpValveMRV-212wasnotse'stingproperlypermittingasignificantamountof-steamtobeexhaustedouttheventstack.Underthesecircumstances,additionalsteamwasbroughtintotheuppervolumewithcondensatecollectingataratefasterthancouldbedrained.MRV-212wasrepairedandsubsequentclosuretestscompletedonMRV-210verifiedthatthis.isolatedincidenthadbeenresolved.AllMSIV'swerereturnedtoanoperablestatusandUnit2returnedtopoweroperation.Asstatedintheanalysis,wedonotexpecttoencountersimilardifficultieswiththeUnit1MSIV's.However,wearecurrentlyaddinginsulationtotheUnit1MSIV's,ventlinesandvalvestoenhancetheMSIVoperatingconditions.IFAILEDCOMPONENTIDENTIFICATIONComponentID:MainSteamIsolationValves2-MRV-210,2-MRV-220,2-MRV-240Manufacturer:Hopkinsons-FerrantiModel:2379WPREVIOUSSIMILAREVENTS050-316/83-57NRCFormSSSA(SSSI NRCFORM344A<Se9)LICENSEEEVENTREPORT{LERITEXTCONTINUATIONt~APPROVEO0MBNO.31500104EXPIRES)4/30/93ESTIMATEDSURDENPERRESPONSETOCOMPLYWTHTHISINFORMATIONCOLLECTIONRFOUESTI500HRS.FORWARDCOMMENTSREGARDINGSURDENESTIMATETOTHERFCORDSANDREPORTSMANAGEMENTBRANCHIPS30),U.S,NUCLEARREGULATORYCOMMISSION,WASHINGTON,DC30555,ANDTOTHEPAPERWORKREDUCTIONPROJECT131504))041-OFFICEOFMANAGEMFNTANDSUDGET,WASHINGTON.DC30503.fACILITYNAMEIl)DOCKETNUMSER)3)YEARLERNUMSER)4)SCOVCNTIALNVMCRIICVISIONNVMCA~AGE13)D.C.CookPlant-Unit2TEXTlllmorpgfdcglgnqvssd,we~HRCJtgwiiSRSC'4)(17)oeo0o316900020008oF10MAINSTEAMISOLATIONVALVETESTTABLEJanuar8,1990TestinVALVEINITIALCLOSINGTIME(SEC)RETEST(SEC)2-MRV-210=2-IIRV-2405.945.183.011.95'Januar~9,1990Testin2-MRV-2102-MRV-2202-MRV-2405.075.605.05"2.832.282.21Januar10,1990Testin2-MRV-2102-MRV-2205.785.733.082.55'anuar11,1990Testing2-MJRV-2205.26NoRetestPerformedNOTE:Duringthetestprogram2-HRV-230closingtimeswerehigh,hut'didnotexceedtheTechnicalSpecificationLimitoffiveSeconds.NRCFoIIm344A144)9)

NRCFORM364A1640)FACILITYNAME111US.NUCLEARAEGULATOAYCOMMISSIONLICENSEEEVENTREPORTILER)TEXTCONTINUATIONDoerETNUMSER(2)APPAOVEDOMSNO,31500)04EXPIRE5:4/30/02ESTIMATEDSUADENPERRESPONSETOCOMPLYWTHTHISINFORMATIONCOLLECTIONREQUEST:500HRS.FORWARDCOMMENTSREGAROINOSUADENESTIMATETOTHERECORDSANDREPORTSMANAGEMENTSRANCHIP430).U.S.NUCLEARREGULATORYCOMMISSION.WASHINGTON.OC20655,ANDTO1HEPAPERWORKREDUCTIONPRO/ECT13)50410E).'OFFICE~OFMANAGEMENTANDSUOGET,WASHINGTON,DC10503.PAGEIS)LEANUMSER(4)D..C.CookPlant-Unit2,TEXT///nxros/>>ce/sr)V/rer/1>>e~PT/Or>>/HIICFerrrrAXLES/(17)YEARosooo31690SEQUENTIALNVM4II002HEY>>ION)rvMER00'09QF10tMAINSTEAMISOLATIONVALVENOTE:VALVESHOWNINCLOSEDPOSITIONOPERATINGPISTON~VENTLINETOSTEANDUMPVALVESSTEAMNIPPLECONDENSATEDRAINLINECONDENSATEDRAINPORTVALVEMODIFICATIONSCONDENSATEDRAINPORTINITIALLY-0125"MODIFIEDTO-.0..'197"(5MM)STEAMNIPPLEINITIALLY"0'125"MODIFI'EDTO0.394"(10MM)~~4/g,.NRCForm346A(680)

NRCFORM385A(54ISIU.S.NUCLEARREGULATORYCOMMISSIONLICENSEEEVENTREPORT(LER)TEXTCONTINUATIONAPPROVEDOMSNO.315040104EXPIRES;4I30JS3ESTIMATEDSURQENPERRESPONSETOCOMPLYWTHTHISINFORMATIONCOLL'ECTIONREQUEST:50.0MRS.FQRWARQCOMMENTSREOAROINObUROEHESTIMATETOTHERECORDSANDREPORTSMANAOEMEHTSRANCHIf@30).U.S.NUCLEARREOULATORYCOMMISSION.WASHINOTOH,DC30555,AHQTQ1HEfAPFRWORKREDUCTIONPROJECT131504)104),QffICEOFMANAGEMENTAHDSUDOET,WASHINGTON,DC30503,fACILITYNAMEIl)DOCKETNUMSER13)YEARLERNUMSERIblSEOVENTIALNVMSEIIII5VISIONNVM~IIPACEISID.C.CookPlant-Unit2TEXTIllII>>IFZ>>ceJFIP0vbe4uwFIRRSN>>FJYRC%%dYm~3Il)T),osooo3l6900020010OF]0HAINSTEAMISOLATIONVALVEVENTPIPINGVENTSTOATMOSPHEREDUMPVALVES3-WAYMOTOROPERATEDVALVEMSIVHRCF~SeSAISJISI