ML17320B063

Forwards Responses to Questions Raised by Anl at 840329 Meeting in Support of Cycle 5 Reload Application

ML17320B063
Person / Time
Site:	Cook
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: ML17320B063 ML17320B065
References
AEP:NRC:0860I, AEP:NRC:860I, NUDOCS 8405220199
Download: ML17320B063 (17)

Text

REGULATOR'l

'4FORHATION DISTRIBUTION S,EM(BIDS)ACCESSION NBR:8<i05220199DOC.DATF:84/05/17NOTARI'C'ED; NODOCKET¹FACIL:50-316 DonaldC~CookNuclearPowerPlantiUnit2iIndiana805000316AUTHBYNAMEAUTHORAFFILIATION ALEXICH<M.P.

IndianaLMichiganElectricCo.RECIP~NAMERECIPIENT AFFILIATION DENTONgH.Ro OfficeofNuclearReactorR'egulation~

Director

SUBJECT:

Forwardsresponses toquestions raisedbyANLat840329meetinginsupportofCycle5reloadapplication.

DISTRI.BUTION CODE+A001SCOPIESRECK'IVEDeLTR KNCLlSIZEed(,',~~+KTITLE:ORSubmittal:

GeneralDistribution NOTESRECIPIENT IDCODE/NAME NRRORB1BC01COPIESLTTRENCL77RECIPIENT IDCODE/NAME COPIESLTTRENCLINTERNAL; ELD/HDS3NRR/DLDIR~IBEXTERNAL:

ACRSNRCPDRNTIS04090210111111661'11NRR/DE/MTEO NRR/DL/DRAB NRR/DSI/RA'B RGN3LPDRNSIC0305LTOTALNUMBEROFCOPIESREQUIRED:

LTTR25ENCL23 r.'tfA'vE"lfllff'll0lIfg41IlI,lltllEflIflleffflllliIlII INDIANA8MICHIGANELECTRICCOlttIPANY P.O.BOX16631COLUMBUS, OHIO43216May17,1984AEP:NRC:0860I DonaldC.CookNuclearPlantUnitNo.2DocketNo.50-316LicenseNo.DPR-74Cycle5ReloadMr.HaroldR.Denton,DirectorOfficeofNuclearReactorRegulation U.S.NuclearRegulatory Commission Washington, D.C.20555

DearMr.Denton:

Wearet;ransmitting Attachments 1,2,3,4and5inresponsetoaverbalquestionraisedbyyourconsultant, ArgonneNationalLaborat;ory, duringameetingamongtheNRCst;aff,ArgonneNationalLaboratory, ExxonNuclearCompany,andAmericanElectricPowerServiceCorporation.

ThemeetingwasheldonMarch29,1984atyourfacility.

Thisresponseissubmitted insupportoftheDonaldC.CookUnitIICycle5reloadapplication.

Thisdocumenthasbeenpreparedfollowing corporateprooedures whichincorporate areasonable setofcontrolstoensureitsaccuracyandcompleteness priortosignature bytheundersigned.

Verytrulyyours,M.P.AlexkahIllIls4VicePresident buscc:JohnE.DolanW.G.Smith,Jr.-BridgmanR.C.CallenG.CharnoffE.R.Swanson,NRCResidentInspector

-Bridgman8405220i99 840517PDRADOCK050003thP...PDR LI Attachment 1Question:

Howistheinadvertent borondilutionatshutdownwhileonRHRtransient treated,andwhyisenoughtimetoanticipate theconsequences available2

Response

OnJuly14,1980aletterfromF.NoonoftheWestinghouse ElectricCorporation totheDonaldC.CookNuclearPlant,PlantManagerwasreceived.

Theidentifier forthisletterisAEP-80-71.

Ztisidentical incontenttoAttachment 1oftheJuly8,1980letterfromT.M.AndersonoftheWestinghouse ElectricCorporation toVictorStellooftheNRC.Theidentifier ofMr.Anderson's letterisNS-TMA-2273.

AEP-80-71 isincludedasAttachment 2.TheDonaldC.CookNuclearPlant'sresponsetotheinadvertent borondilutionatshutdownwhileonRHRtransient isbasedonAEP-80-71.

WhenoneoftheDonaldC.Cookunitsisinmodes4,5or6onRHR,theboronconcentration ismaintained sothattheplantisintheregionof"acceptable operation withoutbankwithdrawal" ofFigureA-1ofAppendixAtoAEP-80-71.

Thisisaccomplished byincreasing therequiredboronconcentration requiredbytheshutdownmargincalculation nearthebeginning ofcycle.Theboronconcentration requiredforN-1rods,noxenon,Unit2,Cycle5isdisplayed inAttachment 3.Ztisfigure4.5ofDCCoop~U~tPggt~Te~gg~~t~Bggk.

Atboronconcentrationshigherthan640ppm,theboronconcentration requiredforshutdownisincreased abovethatrequiredforKeff=0.984.The68Fcurve,whichisdeveloped forusebelow0350F,iscalculated bythemethoddescribed inAttachment 4.Thedilutionrateisassumedtobe225gpm,thevalueusedfortheUnit1dilutionduringrefueling transient.

SeeSection14.1.5oftheFSAR.Thecalculation isdoneinaconservative mannersoastomaximizetheboronconcentration andhencethetimerequiredtodilutetocritical.

ltisalsoconservative inthattypically allrodsareinsertedinmodes4,5or6whereastheKeffinAttachment 3iscalculated ontheassumption thatthemostreactiverodisstickingout.Thisresultsinapproximately 1$ofadditional reactivity todiluteoutpriortocriticality whichisnotincludedinthecalculation.

Furthermore, thecalculation isconservative inthata100ppmallowance isaddedtotheshutdownmargincurve.This100ppmmustalsobedilutedpriortoachieving critical.'t BOL(Capproximately 1600ppm)CZP,halfloopwhentheplantismostvulnerable, 100ppmamountstoapproximately 1.2$ofadditional reactivity.

A'ttachment 10PagetwoTheoperatorhastheinformation available whichwasassumedinAEP-80-71.

Theseare:1.SourceRangeNeutronFluxwith,a.HighFluxatShutdownAlarmsetathalfadecadeabovebackground.

b.Useoftheaudiblecountrateindication todistinguish significant changesinflux,i..e.,adoublingofthecountrate.c.Periodic, i.e.,frequentsurveillance oftheSourceRangemetersperformed bytheoperator.

2.Statusindication oftheChemicalandVolumeControlSystemandReactorMakeupWaterSystemwith,a.Indication ofboricacidandcleanmakeupflowrate,b.CVCSvalvepositionstatuslights,andc.ReactorMakeupWaterPump"running" statuslight.Procedural guidanceforrespond1ng toaninadvertent borondilutionincidentiscontained intheannunciator responseforSourceRangeH1ghFluxatShutdownandEmergency Borationprocedures.

Theseprocedures deviatefromtherecommended Westinghouse responseinthatourpreferred actionforareactivity increaseisemergency boration.

Useofthe"refueling watersequence" isanalternate response.

Webelievethis.isappropriate forseveralreasons:1.75gpmofconcentrated boricac1dwhenmixedwith225gpmofwaterhasaboricacidconcentrat1on greaterthan2000ppm.2.Inmodes5and6the"refueling watersequence" maynotbeavailable asaborationpath.3.Ouroperators haverepetitively andtraditionally beentra1nedtoemergency borateforanyunexplained oruncontrolled reactivity increase.

Toreducetheprobability ofthistransient occurring, certainplantmakeupwater(PMW)valvesaretaggedshutpriortodra1ningtheprimarysystemtohalfloop.Thevalves1nquestionsupplytheboricacidblender,2-PW-263, thechemicalmixingtank,2-PW-256, andthePMWflushtotheemergency borationline,2-PW-265.

Thesetagsareliftedaspartofthevalvelineupforfill1ngandvent1ngtheprimarysystem.Attachment 51sacopyof2-OHP4021.002.005, "Draining theReactorCoolantSystem".

Attachment 1PagethreeAEP-80<<71 indicates thatoperating theplantintheregionof"acceptable operation withoutbankwithdrawal" onFigureA-1ensuresthat"theplantoperatorhasfifteenminutesfromtheinitiation ofthedilutioneventtoterminate theeventbeforeareturntocriticaloccurs".Asindicated above,we,haveapplied'FigureA-1withsignificant conservatism.

Therefore, thetransient willrequire15minutesorlongertoreachcriticality intheabsenceofoperatorintervention.

ATTACHMENT 2I).'"DIDYM!Igag';(i;;(;;(,Westinghouse ElectricCorporation WaterReactorOivisions Ir....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:"~CEtVZOJULI8tgsoTechrricat peptAmericanE1ectricPowerSystem0.C.CookUnits1and2TNAOVERTENT 8GRGNOILUTIONATSHUTOOWNWHILECNRHROnJune27,1980,youwerenotifiedofcer.ainWestinghouse concernsandrecommended ac:ionsregarding thepotential foraninadvertent borondiluticneventatcoldorhotshutdownconditions whileontheResidualHeatRemovalSystem.Thisnotificaticn wasinaccordwithWestinghouse determination thattheseconcernsconstitr;te anUn-reviewedSafetyquestionunderlOCFRPart50.59.TheNRCOfficeofInspection andEnforcement wasalsonotifiedonJune27,1980thattheseconcernshavegenericapplicability toWestinghouse-supplied nuclearpowerplants.Furtherclarification wasmadetotheNRCOfficeofInspection andEnforcement onJune30,1980thatWestinghouse concernsarenotapplicable whiletheplantisgreaterhan5~shutdown.

Thisletterisintendedtoformallydocumenttheseconcernsandtoprov:deadditonalrelevantinformation.

Thisletteralsomodifiestheearlierrecommended ac-onsoyamoredetailedspecification ofapplicaole plantoperating conditions.

Inadver.ent borondilutionatshutdownhasbeengenerally regardedasaneventwhichcanbeidentified andterminated "yoperatoracticn.priortoareturntocri.ical.

Autcmatic protection hasnotbeenastandardfeatureforWestinghouse plants.Westinghouse hasrecentlybeenconducting ageneralinvestigation ofthispotential eventrelat',ve tothelicensin'g requirements imposedcnnewe.plantsnotyetinoperation.

Tnisinvestigation isnctyetcomplete.

However,ithasbeendetermined thatundercertainshutdownconditions andwithcertainass"meddilutonrates,adequate".'meforcoeratcractiontopreventareturntocriticalmaynotbeavailable.

~~July9,1980Page2Thecurrentwestinghouse evaluations arebasedonplantconditions asnotedbelow:1.TheReac-orCoolantSvstameffec=ive volumeislimiohevesselandtheactiveacrticnsorthehotandcoldleos<<henoni.a.stem+eneraarv~m1~Z.TheplantisboratadoashutdownmargingraerthanorequaltaIak/k.3.UniformmixingocleanandbaratadRCSwaterisnotassumed,i.e.,mixingcf:,".eclean,injecedwaterandthearfactedlocaisassumedbutinstantaneous, uniormmixingwihthevessel,hotlegs,andcoldlegvolumesu"streamofthecharginglinesisnotassumed.Tnusa"dilution front"moveshroughthecoldlegs,downc"mer, andlowerplenumtohecorevolumeasasinglevolumefront.Thisresultsinsubsequent decreases inshutdownmarginduetodilutionfrontsmovingthraughtheactivecareregionwitha,timeconstantequaltathelooptransittime<<henanRMR(fivetosevenminutes).

Ifareturntocriicaloccursasaresultofaninadvertent

dilution, thefollowing potential concernshavebenidentiried:

1.Arapid,uncontrolled powerexcursion intothelowandintermediate powerrangesoccurs,resulting inapower/flow mismatchdueathelowflow(approximately 1-2ofnominal)providedbytheRHRclumps.z.The'potential existsrorsignificant systemaverpressurizatian.

Pressureincreases abovetheRHRcutof,head(approximately 500psig)furtheraccentuate theef,ec:sofapower/flow mi'smatch whenallRCS(RMR)flowislost.Aninvestigation oftheadequacyofexistingcoldever"ressuri atcnprotec'onsystemsisnecessary inordertaassessthefullimpactoithispotential orablem.r3.The'catential existsforlimitedfeldamage.Tnisisnotcrrentlyasignificant concern.?reliminaryevaiuation'indicates hatthepotential orexceecing OHBlimi>>sislawduetathecoldinitialooera.ing conditions.

iurtherinvestigation ofthis"raolemisuncerway.

Therecamme..ced

ntar.'mac=.'ors

""."eventarmitcata aninadverant"arandt':cnatshu-"cwncnc';:i-ns

=-",edetailedinAcpencixA.nc=cc'<edc"ntralraasarerequirec,asspecriedin;.'creA-l,ne July9,1980Page.3plantoperatorhasfifeenminutesfromtheintiation ofdilutioneventtoterminate theeventoeforeareturntocriticaloc"urs.itisŽheWestinghouse cositionthataiftaenminutetimeintervalfromtheinitiation ofthediRutiontothetimeshutdownmarginislostissuf-ficienttimeforoperatorac.ion..'f cockedcontrolrodsarereouired, thesourceranereac:"rtriaQroviCes"osltsve1nascat-on';or

>mmeolata operatoract;ontoterminate aiutlon.:tisexpectedthattheoperatorhasavailable thefollowing information fordetermination thatadilutionevent,isinprogress'.

SourceRangeNeutronFluxwith,a.HighFlux.atShutdownAlarmset,athalfadecdeabovebackground.

b.Useoftheaudiblecountrataindication todistinguish significant changesinfluxi.a.,adoublingofthecountrate.c.Periodic, i.e.,freouentsurveillance oftheSourceRangemetersperformed by.heoperator.

2.Statusindication oftheChemicalandVolumeCanrolSystemandReactorMakeupMaterSystem~ith,a.indication ofboricacidandblenced(total)flowraa,orb.indication ofboricacidandcleanmakeupflowrate,c.CVCSvalvepositionstatuslights,andd.Reactori4iakeupMaterPmo"".unning"statuslight.Theoperatoractionnecessary upondeterminat'on thatadilutione'ient.isinprogress(byHighFluxatShutdownAlarm,SourceRangeReacorTrip,"P-6Availanle'naicztion, highindica:ad oraudiblecountrates,ormakeuoflowdeviation alarms)is:l.ammed-'ately "cen:"ec.".argirg/Si RMS7(thatopenonreceipt"Iant"esa-"~IrV-'=-~0=or412pumpsue=onvalvesfromthe"5"s;,"rai).(For312plantspiartstheseareLCV-112-9,

=.)

~t~eg~gJuly9,1980Page42.Immediately cloethecharging/SI pumpsuctionvalvesfromtheVCT(thatcloseonreceiptof'n'S"signal).(For312plantstheseareLCV-11S-C, E.For412plantstheseareLCV-112-8, C.)3.Fortwo-loopplants,immediately openthechargingsuctionvalvesfromtheRWST.(For212plantstheseareLCV-113-8 andLCV-112"C.)

Alsoimmediately closethechargingsuc-ionvalvesromtheVCT.(For212plantstheseareLCV-113-A andLCV-112-B.)

ThroughtheuseofAppendixAanatheabovenotedoperatoractionrequirements, Westinghouse isat.empting tominimizetheoperational burdenplacedontheplanttopreventormitigateaninadvertent dilu-tioneventwhilemqintaining adequatesafetymargin.Ourinvestigation ofthiseventiscontinuing.

Adetailedanalytical modelofthesystemresponseoadilutioneventatshutdownconditions isbeingdeveloped andthepotential forsysemoverpressurization andfuelfailurewillsubsequently beassessed, TheWestinghouse investigation isexpectedtobecompleted bySeptember 15,1980.Wewillkeepyouinformedastotheresultsofourefforts.Verytrulyyours,SR4/B819/20 EasternRegionWNISupport'Icc:R.W.Jurgensen J.E.OwyerW.

APP~HOIXAFiguroA-l,attached, provides-.heshut"cwnmarginrquiremnwsa=unc:ionofQeactorC"olantSystemboronc"ncentrat;cn ardmaximumpossibledilutionflowrate.Priortouseo=thisinureeGiantmus:determine

.hemaximumdilutGnrlowrat4ofallchargingpumpsnotrencaroainooerable onc'.he:lantisplacedon~uq.7ocoverallmodes,itshouldssumdthattheflewr'teisbasedonpumprunoutunlesstherearef'.cwI1"ngde'Ilcasn"'lesystem,'ol lcas,pp-ingresistances, ec.).,lneReactorNakeup'Qatarpumpcapacitymaybelimiinginthedetermination ofthemaximumpossibiedilutionf',cwra=a.FlgurA-1notesar4asoraccept4ble operation ofthroedif-,ar4nt

-ilutionrlcwratesasafunctionofRCSboroncconcactration andboratadshut"ownmar,in(<--).Foragivendilutionflowrate,i-'heRCSboronconcntrationandshutdownmarginresultinapointplac&to:helertoftherlcwrateline,nocontmlrodbankwi".hdrawal isneca4ssarI.

!fther4sultsplace:heplanttotherighttheline,theneitherthesnut"cwnmarginmustbeincr4aSad suchthattheplantismodedto".hea.ea3ac494bieperaion,GtI,"k/kincontrolrodswithdrawn tocrovideadcitionai shutdownmar".in.The=ripoingcrwithdrawn rocsprovidespositveope.a:-rlnolcatlon thatadilutioneventis;nprogressandadditional time=oroperator".rminatcno=theevent.Inallcases,ashut"ownmarginof5">>ak/k(<-)<pig5)isconsidero>

su-.=icient forcontin-uedoperation wfhoutarequireAient

=o-contrql rodbankwithdrwal.FiguroA-1isbasedonbes-stimatcalculations

-orthe"allrcdsin"configu-ration.Itisreccamended t",.atthe'Pest-ingnouse NuclearpesignRepololJourplantbeusedasarererence indetermining

.heRCSborcnconcntrtionwltnleappropriat censerIatismtoeusedin-he;igur4.

~.".e'<<estingnousa

'(uclearFuelpivisionisavailable toprovidessis=ncin.;.eti;.g-.ec"rstrin:simcosad."ytheFigureA-1requirements.

OseofFigureA-1fsapplicable any"i-etnere.'sbereton/dilution pability;rm-~enormalboricacid'blending sys=~i.Tneabo'Iaprocedure isnotr4qurr4d'=borationand/ormak4upduringcold=ndhctshu="'c<<n isper-,c...,ed ut.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'qisreconmenda 7,ionprcudesteoc"rence0ianinadver~en~diIunion~niLeboraxngorask-'ngup~atr=romi".ei'ASTunder-.geeseconditions.

llWluxlulOIsINCIIIxloIIICIILul(~EIILIIIFA.

4L3>LIIclsssaoauluia

~C.461320Q..LJ((J:.)~~

160014002FIGURE4.5D.C.CookUnit2Cycle5BoronConcentration forN-1RodsInsertedNoXenonKeff=0.984PREPAREDBYISSUEDATE~~>~><APPROVEDbEXPIRATION DATE~4APPROVEOFORUSEIN~Ž~DEPT.5Y12008C4C4o10008000Oo60068F(CZP)400200*NOTE:Includes100ppmallowance forconservatism 1EFPH=1.797x10GWD/MT350F450F5470F(HZP)681012CycleExposure(GWD/MT)1617.9 Attachment 4~hdmm~~3m>~Mmo Sincetheboronconcentration requiredtomaintainashutdownmarginof1600pcmvarieswithcorelifetime, thefuelvendorsuppliescurvesofrequiredboronasafunctionofcorelifeandmoderator temperature.

Theassumption ismadethatthemostreactiverodisstuckoutofthecore.Also,100ppminboronconcentration isaddedforconservatism.

Thecurvessuppliedbythefuelvendordonottakeintoaccounttheborondilutionaccident.

Therefore, thecurvesaremodifiedasspecified inAEP-80-71, Attachment 2,beforeincorporating thecurveinthePlantTechnical DataBook.FigureA-1inAEP-80-71 givestherequiredKeff,hencetheshutdownmarginforagivenboronconcentration.

Thefollowing procedure isusedtorecalculate therequiredshutdownboron.Step1-Interpolate FigureA-1inAttachment 2fordilutionflowrateof225GPMfor"allbanksin"case.Note:maximumdilutionratepossibleis225GPM.Step2-Obtainboronconcentration SB1fromtheinterpolated line(Step1)foraKeffof0.984.Note:Keffof0.984corresponds toashutdownmarginof1600pcm.Step3-Step4-Step5-Step6-Step7-Fromthevendorsuppliedshutdownboroncurveformoderator tempof68Ffindtheburnup(B1MWD/T) corresponding toS1.Correction totheshutdownboronconcentration isnolfnecessary forconcentrations lessthanSB1.ObtaintheshutdownboronSB2for0MWD/Tfromthevendor/supplied, curveformoderator temperature of68F.0IfSB2>SB1'henSB2needscorrection.

//ObtainKeff2corresponding toaboronconcentration SB2from,/FigureA-1andcalculate dp'ef4-0'f8'tKefh./IncreasedPbyanarbitrary factorof1.4Ap=s9xdpNote:Afactorof1.4isconservative fortheiterative solutionrequired.

Attachment 0PagetwoStep8-Obtaintherequiredshutdownboronconcentration where88/SCistheboronworth.Toconservatively calculate SB>,theboronworthischosentobelowestvalueintheboronconcentration andtemperature rangeforwhichSB>isbeingcalculated.

Step9-Drawastraightlinebetweenpoint(SB,0MWD/T)andpoint(SB1,B1MWD/T).ForburnupshighertkanB1MWD/T,thelinespecified inthevendorsuppliedshutdownboroncurveisapplicable.

5'8aSeaS8LM%ID/7B1Step10-Verifythatthestraightlineapproximation isconservative.