ML17320B063

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Forwards Responses to Questions Raised by Anl at 840329 Meeting in Support of Cycle 5 Reload Application
ML17320B063
Person / Time
Site: Cook American Electric Power icon.png
Issue date: 05/17/1984
From: ALEXICH M P
INDIANA MICHIGAN POWER CO. (FORMERLY INDIANA & MICHIG
To: DENTON H R
Office of Nuclear Reactor Regulation
Shared Package
ML17320B064 List:
References
AEP:NRC:0860I, AEP:NRC:860I, NUDOCS 8405220199
Download: ML17320B063 (17)


Text

REGULATOR'l'4FORHATIONDISTRIBUTIONS,EM(BIDS)ACCESSIONNBR:8<i05220199DOC.DATF:84/05/17NOTARI'C'ED;NODOCKET¹FACIL:50-316DonaldC~CookNuclearPowerPlantiUnit2iIndiana805000316AUTHBYNAMEAUTHORAFFILIATIONALEXICH<M.P.IndianaLMichiganElectricCo.RECIP~NAMERECIPIENTAFFILIATIONDENTONgH.RoOfficeofNuclearReactorR'egulation~Director

SUBJECT:

ForwardsresponsestoquestionsraisedbyANLat840329meetinginsupportofCycle5reloadapplication.DISTRI.BUTIONCODE+A001SCOPIESRECK'IVEDeLTRKNCLlSIZEed(,',~~+KTITLE:ORSubmittal:GeneralDistributionNOTESRECIPIENTIDCODE/NAMENRRORB1BC01COPIESLTTRENCL77RECIPIENTIDCODE/NAMECOPIESLTTRENCLINTERNAL;ELD/HDS3NRR/DLDIR~IBEXTERNAL:ACRSNRCPDRNTIS04090210111111661'11NRR/DE/MTEONRR/DL/DRABNRR/DSI/RA'BRGN3LPDRNSIC0305LTOTALNUMBEROFCOPIESREQUIRED:LTTR25ENCL23 r.'tfA'vE"lfllff'll0lIfg41IlI,lltllEflIflleffflllliIlII INDIANA8MICHIGANELECTRICCOlttIPANYP.O.BOX16631COLUMBUS,OHIO43216May17,1984AEP:NRC:0860IDonaldC.CookNuclearPlantUnitNo.2DocketNo.50-316LicenseNo.DPR-74Cycle5ReloadMr.HaroldR.Denton,DirectorOfficeofNuclearReactorRegulationU.S.NuclearRegulatoryCommissionWashington,D.C.20555

DearMr.Denton:

Wearet;ransmittingAttachments1,2,3,4and5inresponsetoaverbalquestionraisedbyyourconsultant,ArgonneNationalLaborat;ory,duringameetingamongtheNRCst;aff,ArgonneNationalLaboratory,ExxonNuclearCompany,andAmericanElectricPowerServiceCorporation.ThemeetingwasheldonMarch29,1984atyourfacility.ThisresponseissubmittedinsupportoftheDonaldC.CookUnitIICycle5reloadapplication.Thisdocumenthasbeenpreparedfollowingcorporateprooedureswhichincorporateareasonablesetofcontrolstoensureitsaccuracyandcompletenesspriortosignaturebytheundersigned.Verytrulyyours,M.P.AlexkahIllIls4VicePresidentbuscc:JohnE.DolanW.G.Smith,Jr.-BridgmanR.C.CallenG.CharnoffE.R.Swanson,NRCResidentInspector-Bridgman8405220i99840517PDRADOCK050003thP...PDR LI Attachment1Question:HowistheinadvertentborondilutionatshutdownwhileonRHRtransienttreated,andwhyisenoughtimetoanticipatetheconsequencesavailable2Response:OnJuly14,1980aletterfromF.NoonoftheWestinghouseElectricCorporationtotheDonaldC.CookNuclearPlant,PlantManagerwasreceived.TheidentifierforthisletterisAEP-80-71.ZtisidenticalincontenttoAttachment1oftheJuly8,1980letterfromT.M.AndersonoftheWestinghouseElectricCorporationtoVictorStellooftheNRC.TheidentifierofMr.Anderson'sletterisNS-TMA-2273.AEP-80-71isincludedasAttachment2.TheDonaldC.CookNuclearPlant'sresponsetotheinadvertentborondilutionatshutdownwhileonRHRtransientisbasedonAEP-80-71.WhenoneoftheDonaldC.Cookunitsisinmodes4,5or6onRHR,theboronconcentrationismaintainedsothattheplantisintheregionof"acceptableoperationwithoutbankwithdrawal"ofFigureA-1ofAppendixAtoAEP-80-71.Thisisaccomplishedbyincreasingtherequiredboronconcentrationrequiredbytheshutdownmargincalculationnearthebeginningofcycle.TheboronconcentrationrequiredforN-1rods,noxenon,Unit2,Cycle5isdisplayedinAttachment3.Ztisfigure4.5ofDCCoop~U~tPggt~Te~gg~~t~Bggk.Atboronconcentrationshigherthan640ppm,theboronconcentrationrequiredforshutdownisincreasedabovethatrequiredforKeff=0.984.The68Fcurve,whichisdevelopedforusebelow0350F,iscalculatedbythemethoddescribedinAttachment4.Thedilutionrateisassumedtobe225gpm,thevalueusedfortheUnit1dilutionduringrefuelingtransient.SeeSection14.1.5oftheFSAR.Thecalculationisdoneinaconservativemannersoastomaximizetheboronconcentrationandhencethetimerequiredtodilutetocritical.ltisalsoconservativeinthattypicallyallrodsareinsertedinmodes4,5or6whereastheKeffinAttachment3iscalculatedontheassumptionthatthemostreactiverodisstickingout.Thisresultsinapproximately1$ofadditionalreactivitytodiluteoutpriortocriticalitywhichisnotincludedinthecalculation.Furthermore,thecalculationisconservativeinthata100ppmallowanceisaddedtotheshutdownmargincurve.This100ppmmustalsobedilutedpriortoachievingcritical.'tBOL(Capproximately1600ppm)CZP,halfloopwhentheplantismostvulnerable,100ppmamountstoapproximately1.2$ofadditionalreactivity.

A'ttachment10PagetwoTheoperatorhastheinformationavailablewhichwasassumedinAEP-80-71.Theseare:1.SourceRangeNeutronFluxwith,a.HighFluxatShutdownAlarmsetathalfadecadeabovebackground.b.Useoftheaudiblecountrateindicationtodistinguishsignificantchangesinflux,i..e.,adoublingofthecountrate.c.Periodic,i.e.,frequentsurveillanceoftheSourceRangemetersperformedbytheoperator.2.StatusindicationoftheChemicalandVolumeControlSystemandReactorMakeupWaterSystemwith,a.Indicationofboricacidandcleanmakeupflowrate,b.CVCSvalvepositionstatuslights,andc.ReactorMakeupWaterPump"running"statuslight.Proceduralguidanceforrespond1ngtoaninadvertentborondilutionincidentiscontainedintheannunciatorresponseforSourceRangeH1ghFluxatShutdownandEmergencyBorationprocedures.TheseproceduresdeviatefromtherecommendedWestinghouseresponseinthatourpreferredactionforareactivityincreaseisemergencyboration.Useofthe"refuelingwatersequence"isanalternateresponse.Webelievethis.isappropriateforseveralreasons:1.75gpmofconcentratedboricac1dwhenmixedwith225gpmofwaterhasaboricacidconcentrat1ongreaterthan2000ppm.2.Inmodes5and6the"refuelingwatersequence"maynotbeavailableasaborationpath.3.Ouroperatorshaverepetitivelyandtraditionallybeentra1nedtoemergencyborateforanyunexplainedoruncontrolledreactivityincrease.Toreducetheprobabilityofthistransientoccurring,certainplantmakeupwater(PMW)valvesaretaggedshutpriortodra1ningtheprimarysystemtohalfloop.Thevalves1nquestionsupplytheboricacidblender,2-PW-263,thechemicalmixingtank,2-PW-256,andthePMWflushtotheemergencyborationline,2-PW-265.Thesetagsareliftedaspartofthevalvelineupforfill1ngandvent1ngtheprimarysystem.Attachment51sacopyof2-OHP4021.002.005,"DrainingtheReactorCoolantSystem".

Attachment1PagethreeAEP-80<<71indicatesthatoperatingtheplantintheregionof"acceptableoperationwithoutbankwithdrawal"onFigureA-1ensuresthat"theplantoperatorhasfifteenminutesfromtheinitiationofthedilutioneventtoterminatetheeventbeforeareturntocriticaloccurs".Asindicatedabove,we,haveapplied'FigureA-1withsignificantconservatism.Therefore,thetransientwillrequire15minutesorlongertoreachcriticalityintheabsenceofoperatorintervention.

ATTACHMENT2I).'"DIDYM!Igag';(i;;(;;(,WestinghouseElectricCorporationWaterReactorOivisionsIr....ywzma!5225/~6JU1y9,1980AEP-80-m<I.v"...ar~sr(~c.00HAIDt'-coopp;g;ttNsS-QI(c~'(rs"rea~zrsMr.0.V.Shaller,PlantManagerO.C.CookNuclearPlan-IndianaandMichiganPowerCompanyP.O.8ox458Bridgman,Michigan49106OearMr.Shal1er:"~CEtVZOJULI8tgsoTechrricatpeptAmericanE1ectricPowerSystem0.C.CookUnits1and2TNAOVERTENT8GRGNOILUTIONATSHUTOOWNWHILECNRHROnJune27,1980,youwerenotifiedofcer.ainWestinghouseconcernsandrecommendedac:ionsregardingthepotentialforaninadvertentborondiluticneventatcoldorhotshutdownconditionswhileontheResidualHeatRemovalSystem.ThisnotificaticnwasinaccordwithWestinghousedeterminationthattheseconcernsconstitr;teanUn-reviewedSafetyquestionunderlOCFRPart50.59.TheNRCOfficeofInspectionandEnforcementwasalsonotifiedonJune27,1980thattheseconcernshavegenericapplicabilitytoWestinghouse-suppliednuclearpowerplants.FurtherclarificationwasmadetotheNRCOfficeofInspectionandEnforcementonJune30,1980thatWestinghouseconcernsarenotapplicablewhiletheplantisgreaterhan5~shutdown.Thisletterisintendedtoformallydocumenttheseconcernsandtoprov:deadditonalrelevantinformation.Thisletteralsomodifiestheearlierrecommendedac-onsoyamoredetailedspecificationofapplicaoleplantoperatingconditions.Inadver.entborondilutionatshutdownhasbeengenerallyregardedasaneventwhichcanbeidentifiedandterminated"yoperatoracticn.priortoareturntocri.ical.AutcmaticprotectionhasnotbeenastandardfeatureforWestinghouseplants.Westinghousehasrecentlybeenconductingageneralinvestigationofthispotentialeventrelat',vetothelicensin'grequirementsimposedcnnewe.plantsnotyetinoperation.Tnisinvestigationisnctyetcomplete.However,ithasbeendeterminedthatundercertainshutdownconditionsandwithcertainass"meddilutonrates,adequate".'meforcoeratcractiontopreventareturntocriticalmaynotbeavailable.

~~July9,1980Page2Thecurrentwestinghouseevaluationsarebasedonplantconditionsasnotedbelow:1.TheReac-orCoolantSvstameffec=ivevolumeislimiohevesselandtheactiveacrticnsorthehotandcoldleos<<henoni.a.stem+eneraarv~m1~Z.TheplantisboratadoashutdownmargingraerthanorequaltaIak/k.3.UniformmixingocleanandbaratadRCSwaterisnotassumed,i.e.,mixingcf:,".eclean,injecedwaterandthearfactedlocaisassumedbutinstantaneous,uniormmixingwihthevessel,hotlegs,andcoldlegvolumesu"streamofthecharginglinesisnotassumed.Tnusa"dilutionfront"moveshroughthecoldlegs,downc"mer,andlowerplenumtohecorevolumeasasinglevolumefront.Thisresultsinsubsequentdecreasesinshutdownmarginduetodilutionfrontsmovingthraughtheactivecareregionwitha,timeconstantequaltathelooptransittime<<henanRMR(fivetosevenminutes).Ifareturntocriicaloccursasaresultofaninadvertentdilution,thefollowingpotentialconcernshavebenidentiried:1.Arapid,uncontrolledpowerexcursionintothelowandintermediatepowerrangesoccurs,resultinginapower/flowmismatchdueathelowflow(approximately1-2ofnominal)providedbytheRHRclumps.z.The'potentialexistsrorsignificantsystemaverpressurizatian.PressureincreasesabovetheRHRcutof,head(approximately500psig)furtheraccentuatetheef,ec:sofapower/flowmi'smatchwhenallRCS(RMR)flowislost.Aninvestigationoftheadequacyofexistingcoldever"ressuriatcnprotec'onsystemsisnecessaryinordertaassessthefullimpactoithispotentialorablem.r3.The'catentialexistsforlimitedfeldamage.Tnisisnotcrrentlyasignificantconcern.?reliminaryevaiuation'indicateshatthepotentialorexceecingOHBlimi>>sislawduetathecoldinitialooera.ingconditions.iurtherinvestigationofthis"raolemisuncerway.Therecamme..ced;ntar.'mac=.'ors:""."eventarmitcataaninadverant"arandt':cnatshu-"cwncnc';:i-ns=-",edetailedinAcpencixA.nc=cc'<edc"ntralraasarerequirec,asspecriedin;.'creA-l,ne July9,1980Page.3plantoperatorhasfifeenminutesfromtheintiationofdilutioneventtoterminatetheeventoeforeareturntocriticaloc"urs.itisŽheWestinghousecositionthataiftaenminutetimeintervalfromtheinitiationofthediRutiontothetimeshutdownmarginislostissuf-ficienttimeforoperatorac.ion..'fcockedcontrolrodsarereouired,thesourceranereac:"rtriaQroviCes"osltsve1nascat-on';or>mmeolataoperatoract;ontoterminateaiutlon.:tisexpectedthattheoperatorhasavailablethefollowinginformationfordeterminationthatadilutionevent,isinprogress'.SourceRangeNeutronFluxwith,a.HighFlux.atShutdownAlarmset,athalfadecdeabovebackground.b.Useoftheaudiblecountrataindicationtodistinguishsignificantchangesinfluxi.a.,adoublingofthecountrate.c.Periodic,i.e.,freouentsurveillanceoftheSourceRangemetersperformedby.heoperator.2.StatusindicationoftheChemicalandVolumeCanrolSystemandReactorMakeupMaterSystem~ith,a.indicationofboricacidandblenced(total)flowraa,orb.indicationofboricacidandcleanmakeupflowrate,c.CVCSvalvepositionstatuslights,andd.Reactori4iakeupMaterPmo"".unning"statuslight.Theoperatoractionnecessaryupondeterminat'onthatadilutione'ient.isinprogress(byHighFluxatShutdownAlarm,SourceRangeReacorTrip,"P-6Availanle'naicztion,highindica:adoraudiblecountrates,ormakeuoflowdeviationalarms)is:l.ammed-'ately"cen:"ec.".argirg/SiRMS7(thatopenonreceipt"Iant"esa-"~IrV-'=-~0=or412pumpsue=onvalvesfromthe"5"s;,"rai).(For312plantspiartstheseareLCV-112-9,=.)

~t~eg~gJuly9,1980Page42.Immediatelycloethecharging/SIpumpsuctionvalvesfromtheVCT(thatcloseonreceiptof'n'S"signal).(For312plantstheseareLCV-11S-C,E.For412plantstheseareLCV-112-8,C.)3.Fortwo-loopplants,immediatelyopenthechargingsuctionvalvesfromtheRWST.(For212plantstheseareLCV-113-8andLCV-112"C.)Alsoimmediatelyclosethechargingsuc-ionvalvesromtheVCT.(For212plantstheseareLCV-113-AandLCV-112-B.)ThroughtheuseofAppendixAanatheabovenotedoperatoractionrequirements,Westinghouseisat.emptingtominimizetheoperationalburdenplacedontheplanttopreventormitigateaninadvertentdilu-tioneventwhilemqintainingadequatesafetymargin.Ourinvestigationofthiseventiscontinuing.Adetailedanalyticalmodelofthesystemresponseoadilutioneventatshutdownconditionsisbeingdevelopedandthepotentialforsysemoverpressurizationandfuelfailurewillsubsequentlybeassessed,TheWestinghouseinvestigationisexpectedtobecompletedbySeptember15,1980.Wewillkeepyouinformedastotheresultsofourefforts.Verytrulyyours,SR4/B819/20EasternRegionWNISupport'Icc:R.W.JurgensenJ.E.OwyerW.

APP~HOIXAFiguroA-l,attached,provides-.heshut"cwnmarginrquiremnwsa=unc:ionofQeactorC"olantSystemboronc"ncentrat;cnardmaximumpossibledilutionflowrate.Priortouseo=thisinureeGiantmus:determine.hemaximumdilutGnrlowrat4ofallchargingpumpsnotrencaroainooerableonc'.he:lantisplacedon~uq.7ocoverallmodes,itshouldssumdthattheflewr'teisbasedonpumprunoutunlesstherearef'.cwI1"ngde'Ilcasn"'lesystem,'ollcas,pp-ingresistances,ec.).,lneReactorNakeup'Qatarpumpcapacitymaybelimiinginthedeterminationofthemaximumpossibiedilutionf',cwra=a.FlgurA-1notesar4asoraccept4bleoperationofthroedif-,ar4nt-ilutionrlcwratesasafunctionofRCSboroncconcactrationandboratadshut"ownmar,in(<--).Foragivendilutionflowrate,i-'heRCSboronconcntrationandshutdownmarginresultinapointplac&to:helertoftherlcwrateline,nocontmlrodbankwi".hdrawalisneca4ssarI.!fther4sultsplace:heplanttotherighttheline,theneitherthesnut"cwnmarginmustbeincr4aSadsuchthattheplantismodedto".hea.ea3ac494bieperaion,GtI,"k/kincontrolrodswithdrawntocrovideadcitionaishutdownmar".in.The=ripoingcrwithdrawnrocsprovidespositveope.a:-rlnolcatlonthatadilutioneventis;nprogressandadditionaltime=oroperator".rminatcno=theevent.Inallcases,ashut"ownmarginof5">>ak/k(<-)<pig5)isconsidero>su-.=icientforcontin-uedoperationwfhoutarequireAient=o-contrqlrodbankwithdrwal.FiguroA-1isbasedonbes-stimatcalculations-orthe"allrcdsin"configu-ration.Itisreccamendedt",.atthe'Pest-ingnouseNuclearpesignRepololJourplantbeusedasarererenceindetermining.heRCSborcnconcntrtionwltnleappropriatcenserIatismtoeusedin-he;igur4.~.".e'<<estingnousa'(uclearFuelpivisionisavailabletoprovidessis=ncin.;.eti;.g-.ec"rstrin:simcosad."ytheFigureA-1requirements.OseofFigureA-1fsapplicableany"i-etnere.'sbereton/dilutionpability;rm-~enormalboricacid'blendingsys=~i.Tneabo'Iaprocedureisnotr4qurr4d'=borationand/ormak4upduringcold=ndhctshu="'c<<nisper-,c...,edut.li-ingwa4rfrythe3AS7.inisr4quires=.".at=.'"enorma1""1ution/cration.:athisSclatadfrom.heChargina'pa:h.TwcmeanSOr1OCk"uttciSOlaatheC:lagingpathareavailable:L."ckoutReac:or.'<akeupviaar'"ciy7115isacPiQllshedy'Ia<ve~1:Lan&,ndva.ve=-'==;;l.-1c,'.=.-.-=.A~'IaI4-i"r~'2

~,~~~l.oczoutvalves".e-~en".".ed'or'cacidblencernd-4eVC7.7heseare;C'!-III3,C'I-IIQB,"339,33="",and8361".or212pIano;,=C'I-II4A,FC(-II".g,gage,0<'I,and8~3o;or312Planets;FC'l-IIIB,;C'/-IICB,3'53,8441,8439=or"12plan~.j'qisreconmenda7,ionprcudesteoc"rence0ianinadver~en~diIunion~niLeboraxngorask-'ngup~atr=romi".ei'ASTunder-.geeseconditions.

llWluxlulOIsINCIIIxloIIICIILul(~EIILIIIFA.4L3>LIIclsssaoauluia~C.461320Q..LJ((J:.)~~

160014002FIGURE4.5D.C.CookUnit2Cycle5BoronConcentrationforN-1RodsInsertedNoXenonKeff=0.984PREPAREDBYISSUEDATE~~>~><APPROVEDbEXPIRATIONDATE~4APPROVEOFORUSEIN~Ž~DEPT.5Y12008C4C4o10008000Oo60068F(CZP)400200*NOTE:Includes100ppmallowanceforconservatism1EFPH=1.797x10GWD/MT350F450F5470F(HZP)681012CycleExposure(GWD/MT)1617.9 Attachment4~hdmm~~3m>~MmoSincetheboronconcentrationrequiredtomaintainashutdownmarginof1600pcmvarieswithcorelifetime,thefuelvendorsuppliescurvesofrequiredboronasafunctionofcorelifeandmoderatortemperature.Theassumptionismadethatthemostreactiverodisstuckoutofthecore.Also,100ppminboronconcentrationisaddedforconservatism.Thecurvessuppliedbythefuelvendordonottakeintoaccounttheborondilutionaccident.Therefore,thecurvesaremodifiedasspecifiedinAEP-80-71,Attachment2,beforeincorporatingthecurveinthePlantTechnicalDataBook.FigureA-1inAEP-80-71givestherequiredKeff,hencetheshutdownmarginforagivenboronconcentration.Thefollowingprocedureisusedtorecalculatetherequiredshutdownboron.Step1-InterpolateFigureA-1inAttachment2fordilutionflowrateof225GPMfor"allbanksin"case.Note:maximumdilutionratepossibleis225GPM.Step2-ObtainboronconcentrationSB1fromtheinterpolatedline(Step1)foraKeffof0.984.Note:Keffof0.984correspondstoashutdownmarginof1600pcm.Step3-Step4-Step5-Step6-Step7-Fromthevendorsuppliedshutdownboroncurveformoderatortempof68Ffindtheburnup(B1MWD/T)correspondingtoS1.CorrectiontotheshutdownboronconcentrationisnolfnecessaryforconcentrationslessthanSB1.ObtaintheshutdownboronSB2for0MWD/Tfromthevendor/supplied,curveformoderatortemperatureof68F.0IfSB2>SB1'henSB2needscorrection.//ObtainKeff2correspondingtoaboronconcentrationSB2from,/FigureA-1andcalculatedp'ef4-0'f8'tKefh./IncreasedPbyanarbitraryfactorof1.4Ap=s9xdpNote:Afactorof1.4isconservativefortheiterativesolutionrequired.

Attachment0PagetwoStep8-Obtaintherequiredshutdownboronconcentrationwhere88/SCistheboronworth.ToconservativelycalculateSB>,theboronworthischosentobelowestvalueintheboronconcentrationandtemperaturerangeforwhichSB>isbeingcalculated.Step9-Drawastraightlinebetweenpoint(SB,0MWD/T)andpoint(SB1,B1MWD/T).ForburnupshighertkanB1MWD/T,thelinespecifiedinthevendorsuppliedshutdownboroncurveisapplicable.5'8aSeaS8LM%ID/7B1Step10-Verifythatthestraightlineapproximationisconservative.