ML17326A883

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Evaluation of Facility Containment to Determine Limiting Internal Uniform Pressure Capacity. Prepared for American Electric Power Co
ML17326A883
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Site: Cook  American Electric Power icon.png
Issue date: 03/16/1981
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SMA-80C129-1, NUDOCS 8104290520
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{{#Wiki_filter:SMA.8OC129-1SECTION1EVALUATIONOFD.C.COOKCONTAINMEiNTTOOETERMINELIMITINGINT""RNiALUNIFORMPRESSURECAPACITYPreparedfor:americanElectricPowerCo.2BroadwayNewYork,N.Y.1000416March1981Preparedby:StructuralMechanicsAssociates3645'i(arrensvilleCenterRd.Cleveland,Ohio44122(216)991-8841 TABLEOFCOilTEl<TS1.0Introduction1.1PurposeandScopeofReport1.2EvaluationCriteria1.3ContainmentDescriptionandDesignBasis1.4MaterialProperties2.0IdentificationofLimitingFailurei~iodesAssociatedwithUniformStaticInternalPressure3.0PotentialFailureModeAnalysis3.1ShearFailureinBaseHat3.2blembraneHoopTensionFailureofConcreteCylinder3.3PressureCapacityofEquipmentHatchClosure3.3.1SplicePlateHomentCapacity3.3.1.1HandCalculation3.3.1.2FiniteElementAnalysis3.3.2EquipmentHatchCoverPlatePressureCapacity3.4PressureCapacityofPersonnelHatch3.4.1EndPlateClosure3.4.2Door4.0SummaryandConclusions

1.0INTRODUCTION

PURPOSEANDSCOPEOFREPORT-TheobjectofthisreportistodetermineabestestimateofthelimitinguniformequivalentstaticinternalpressurecapacityofthecontainmentstructuresfortheO.C.CookNuclearGeneratingUnitsNo.1and2.Theevaluationreportedislimitedtothereinforcedconcretebasemat,thereinforcedconcreterightcircularcylinderandhemisphericaldomeaswellasmajorcontainmentpenetrationsincludingtheequipmentandpersonnelhatches.ThisreportcompletesPhaseIofathreephaseeffortwhichwillincludeasPhaseIIanupperandlowerboundestimateoftheinternaluniformequivalentstaticpressurecapacityofthe"asbuilt"containmentstructuresandPhaseIIIwhichwillconsiderpotentialtimedependentlocalizednon-uniformpressureloadeffects.1.2EVALUATIONCRITERIATheevaluationtodeterminingthelimitingbestestimateuniformstaticpressurecapacityofthecontainmentstructuresisbasedonalinearelasticanalysisofcriticalportionsofthestructureuptostresslevelslimitedby"asbuilt"meanvaluesamplesoftheyieldinsteelandultimatestrengthoftheconcrete.Itshouldbeunderstoodthatthestructuralandleaktightintegrityofasteellinedconcretecontainmentshellandslabstructureshouldbemaintainedwellbeyondactualyieldofthesteelreinforcement.Thisisdueprimarilytotherelativehighductilityofthesteelliner,(ie.20-23percentuniformultimatestrainatrupture)comparedto.the40ksisteelreinforcement(ie.8-11percentuniformultimatestrainatrupture)andstrainhardeninginthereinforcement.Hencethelineringeneral~ouldbeabletoaccomodaterelativelylargenonlineardeformationoftheconcretestructurebeforesignificantleakagewouldoccur.However,sincedeformationsbeyondtheyieldrangearedifficulttopredictandlocalizddeformationsinthestructurecansignificantlyexceedthosecalculatedglobally,thelimitinginternalpressurehasbeendeterminedconservativelyconsideringonlyassumedelasticresponseuptotheinitialyieldofthematerialsused.Itistheauthor'sopinionbasedontheobservedresultsofmodelteststhatsignificantleakage(>1.0prcentofcontainmentvolume)ofthecontainmentwouldnotoccuruntiloressuresexceededthelimitingoressurescalculatedinthisstudybyatleast20percent.Assumingacompositecoefficientofvariationof10percentandalognormaldistributionofmaterialpropertiestheprobabilityofsignificantleakageatthepressureleveldefinedinthisstudywouldbeapproximately0.01.TheprobabilityofsignificantleakageandupperandlowerboundsonpressurewillbeevaluatedinmoredetailinPhaseII. CONTAIililENTOESCRIPTIOHAtl0DESIGNBASISThereactorcontainmentstructureisareinforcedconcreteverticalcylinderwithaflatbaseandahemisphericaldomeasshowninFicure1:Aductileweldedsteellinerwithathicknessof1/4-inchonthecontainmentbaseand.3/8-inch'ontheCylinderisstudattachedtotheinsidefaceoftheconcreteshelltoinsureahighdegreeofleak-tightness.Thedesignobjectiveofthecontainmentstructureistocontainallradioactivematerialwhichmightbereleasedfromthereactorcoolantsystemfollowingapostulatedlossofcoolantaccident.Thestructureservesasbothabiologicalshieldandapressurecontainer.Thestructureconsistsofsidewallsmeasuring113-feetfromthelineronthebasetothespringlineofthedome,andhasaninsidediameterof115-feet.Thesidewallthicknessofthecylinderattnebaseis4.5ft.taperingto3.5ft.,sevenfeetabovethebasematandcontinuingat3.5ft.tothespringline.Thereinforcedconcretethicknessofthedomevariesuniformlyfrom3.5ft.atthespringlineto2.5ftattheapexofthedome.Theinsideradiusofthedomeisequaltotheinsideradiusofthecylinder.Theflatconcretebasematis10-ft.thickwithanoutsidediameter,of140'-0"andwiththebottomlinerplate1/4"thicklocatedontopofthismat.Thebotto~linerplateiscoveredwitha2-ft.structuralslabofconcretewhichservestocarryinternalequipmentloadsandformsthefloorofthecontainment.Thebasematissupporteddirectlybyrelativelystiffsoil.Thebasicstructuralelementsconsideredinthedesignofthecontainmentstructureisthebaseslab,sidewallsanddomeactingasonestructureunderallloadingconditions.Thelinerisanchoredtotheconcreteshellwallsbymeansofstudanchorssothatitformsanintegralpartoftheentirecompositestructureunderallmembraneloadings.Thereinforcinginthestructurehasanelasticresponsetoallprimarydesignloads.Thebasematis10'-0"thickand140'-0"indiameter.Thereinforcementinthetopofthebaseslabconsistsprimarilyofonelayerof818Sbarsat12"c/cinthehoopand2layersof58Sbarsat9"c/cin'theradialdirections.Thebottomreinforcementconsistsof2layersof818Sbarsat12"c/cinthehoopand3layersofalternate818Sand811barsat9"c/cintheradialdirections.ThebaseslabwaspouredintwofivefootliftswhicharetiedtogetherinordertotransmithorizontalshearinducedbybendingmomentsbyshearkeysandverticalAllbarsat6'-0"c/cspacing.

Themembranehoop(horizontal)reinforcementinthecyclinderwallsisgenerallyintworows,oneoneachfaceconsistingofN18Sat18"c/ccircumferentiallyextendingto20'bovethebasematreducedto9"c/cspacingbetween20'nd57'bovethebaseandthenincreasedto12"c/cspacingbetween57'nd113'springline)abovethebasemat.Themembranemeridional,(vertical)reinforcementinthecontainmentshellconsistsprimarilyoftwolayersoneoneachfaceof818Sbarson18"c/c.Intheregionofdiscontinuityat'hebasemattheamountofverticalreinforcementisdoubledto4layersof~18barsat1S"c/candatthecylinderdomeintersectiononeverticalstaggerdrowof411barsat18"c/cisaddedtotheexistingmembraneverticalreinforcementtoprovidediscontinuitybendingmomentresistance.Inadditiontotheverticalandhorizontalmembraneandbendingreinforcingsteel,inplanediagonalreinforcementhasbeenprovidedtocarryseismicallyinducedmembraneshear.The45degreediagonalbarsconsistof811barsspaced3'-0"onthehorizontalc/cplacedintworowsineachfaceandineachdirection.Thediagonalreinforcementisembeddedinandextendsfromthebasematto4-3"abovethespringlineintothedomeforalternatebarsand7'-0"fortherestofthediagonals.Thedomereinforcementconsistsof818barsat18"c/cineachfaceineachdirection.Thecontainmentstructureenclosesanicecondensercontainmentsystemwhichisdesignedtolimitpressurizationothecontainmentunderdesignbasisaccidentconditionsto12.0psi.Othersignificantdesignloadparametersaretheequivalentsafeshutdownearthquakeloadingof0.2gzeroperiodgroundaccelerationandadesignbasistornadoof360mph.windandand3.0psidifferentialpressure.Hotprocesspipepenetratingthecontainmentareanchoredinthecontainmentshellwiththeanchorsdesignedtoresistthepostulatedruptureoftheprocesslinewithoutlossofcontainmentleaktightintegrity.Aloadfactorof1.5(additionalsafetyfactor)isusedwiththeinternalpressurecomponentofdesignloadwhilealoadfactorof1.0isusedwithboththeSSEandTornadoloading.!)ATERIALPROPERTIESTheparticularspecifiedminimummaterialspropertiesusedintheconstructionofthecontainmentsaresummarizedasfollows:(a)concrete-fc=3,500psiat28day(ACI-308-63,301,66,and214-65)(b)reinforcingrod-fy=40,000psi(ASTNA15) (c)linerplate=-fy=32,000psi;fu=60,000psi(ASTtlSA442-Gr.60)(d)equipmenthatch-fy=38,000psi;fu.=70,000psi(ASTHSA516-Gr.70)(e)personnelhatch-fy=38,000psi;fu=70,000psi(ASTt<SA516-Gr.60)(f)hatchbolts-fy=105,000psi;fu=125,000psi(ASTHSA193-6r.87)InTable1canbefoundasummaryofthe"asbuilt"strengthsaswellasameasureofthedispersior.associatedwiththematerialsusedinthecontainmentconstruction,basedonalimitedsampleofexistingtestrecorddata.AspartofPhaseIIofthisevaluationamoredetailedevaluationof"asbuilt"materialpropertydatawillbedeveloped.2.0IDENTIFICATIONOFLItiITINGFAILURENODESASSOCIATEDMITHUNIFORi~lTATICNRNALPEUInselectingthepotentiallimitingfailuremodesassociatedwithequivalentstaticuniforminternaloverpressurizationofaPPRreinforcedconcreteicecontainmentanumberofexistinganalyseshavebeenreviewed'.Theseincludethefollowingreferences:Harstead,G.A."D.C.CookNuclearPowerPlant,AmericanElectricPower,EstimateofUltimatePressureCapacityofContainmentStructure",HarsteadEngineeringAssociates,ReportpreparedfortheNRCStaff,September,1980.(SeeAttachmentA)(2)VonRiesemann,M.A.et.al."StructuralResponseofIndianPoint2and3ContainmentOuildings"SummaryofDraftReport.resultspresentedto!IRCStaff,Technology-Exchanget~eeting5,17June1980.(3)(4)(5)(6)UnitedEngineersandConstructors"EvaluationofCapabilityofIndianPointContainmentVesselsUnits2and3"presentedtoNRCStaff,TechnologyExchangeileeting5,17June1980.AmericanElectricPowerServiceCorp.,"D.C.ContainmentDesignCalculations,AEP,1969.S.3arneset.al.IndianPoint!!uclearGeneratinUnitNo.2ContainmentDesinRepor~,'!estinghouseNucearEnergyystems,UnitedEngineersandConstructors,!larch,1969.Shulman,J."AnalysisofTVASequoyahContainmentShelltoDetermineResponseofaCriticalPaneltoUniformInternalPressure",OffshorePowerSystems,September,1980. Basedonthisreviewthefollowingareashavebeenidentifiedaspotentiallylimitingthecontainmentcapacitytocarryuniforminternalpressureload.(1)Bendingshearinthereinforcedconcretecontainmentbasematadjacenttoreinforcedconcretecylinderwalls.(2)flembranetensioninhoopdirectioninthereinforcedconcretecylinderadjacenttothebasemat(assumingnorotationalorshearrestraintbythecylinder).(3)Bendingmomentinequipmenthatchendplate.(4)Bendingmomentinpersonnelhatchendplate.3.0POTENTIALFAILUREblODEANALYSIS3.1SHEARFAILUREINBASEYATTheprogramusedtodeterminenetshearandtensileforcesinthebaseslabis"GENSHL"whichwasdevelopedbytheFranklinInstituteResearchLaboratoryofPhiladelphia.Theprogramconsistsofamulti-layeredstaticshellformulationwhereeachshelllayermayhavedifferentstiffnessoropertiesandcanconsiderelasticfoundationsupportconditions.Thisisthesameprogramthatwasusedintheoriginaldesignandanalysisofthebaseslabfordesignbasisloadings.Auniformsoilreactiondistributionisusedfordeadloadplusinternaluniformpressurecase.Resultsoftheanalysisaresummarizedasfollows:1.Specifiedminimumdesignstrengthofconcreteat28days=3,500psi2.t<eanSampleValueat28days3.flinimumSampleValueat28daysFoundationSlab:=4,950psi=4,156psiT=120inchesd=114inchesFromcomputeroutputasshowninTables2and3atsectionsindicatedin.Figure2:

Evaluationforlowestmeasuredconcretestrengthvalue:NxzQxsk/ink/inComp+RunCase12.0psi,internalpressureAssume49.5psi,internalpressureOeadLoadOL+49.5psipressure1.8987.8291.3009.129-2.948-12.160-0.193-12.353SoilPar.1SoilPar.1SoilPar.5v=i~=12.353x1000=108.36psiwhere:Nxi=membranetensioninbaseslabQia=maximumverticalshearinbaseslabv=maximumshearstressinbaseslabFromAStlESectionIII-Oivision2andACI-359-80CodeforConcreteReactorYesselsandContainmentsCC3421.4.1rIUsinglowestmeasuredmeanvalueofconcretestrength:vc-2r0pfc(1+IOr002Nu/Agjjr-,rc=20~4166!1+[00021-9.129x1000xtfltvc=2(64.46)[1-0.152]=103.59psiNote:InternalPressureCapacitywherevernotedas"Psi"means"Psig"-~gggQgllXCLXt%~RX2~M Evaluateformeanofmeasuredconcretestrengthvaluesk/inQx.ak/inComp.RunAssume53.8psi,internalpressureOeadLoadOL+53.8psipressure8.5091.3009.809-13.217-0.193-13.410SoilPar.1SoilPar.5v=13.410(10)1x114v"-117.63psivc=274950)1+I0.002(-9.809x1000~,1balllvc=2(70~356)C1-0.1635jvc=117.71psiInlikemanneritcanbeshoNnforaspecifiedminimumconcretestrengthfc=3500psithattheinternalpressurecapacityis46.4psi.Inthisevaluationnocreditistakenforthevertical/Illbarat6'/cinthebasematnorisanycredittakenforshearcapacityofthefillslababovethebasemat.Intable4canbefoundthelimitingpressurecapacityadjustedfortheassumptionofminimumspecifiedandminimumsampledmaterialpropertiesasdefinedinTable1.InReference1theHarseadreportPg.5-1-1identifiedafailuremodebasedontheassumedpulloutoftheverticalmembranesteelinthecylinderwallfromthebasematashavingacontainmentinternalpressurecapacityof46psi.Tnepulloutfailuremodecapacityof46psiinternalpressurecapacityofthecontainmentwasdeterminedivithoutconsiderationoftheradialshear(diagonaltension)capacityoftheconcretevihichispermittedbytheACI-359codeeveninpresenceofmembrantension.Toignoretheshearcapacityoftheconcreteisnotinaccordanceriithnormaldesignnoranalysisprocedures.Hencethefailurepressureintheconcretecontainmentof53.8psiasdefinedbythecalculationsperformedinthissectionislimiting. 3.2MEHBRA</EHOOPTHSIO'lFAILUREOFCOtlCRETECYLII>OERi~lembraneloadduetocontainmentpressurizationinthehorizontal(hoop)directionP=pRwhere:P=membraneloadinlbs/inofwallp=uniforminternalpressureR=meanradiusofwall(57.5x12=690inches)Hembraneloadcapacityofreinforcedconcretecylinderatitsbaseneglectingdiscontinuitymomenttransfer:AvailableReinforcement1)2Layers818barhoopreinforcementat18"c/c=8in=5.33in2/ftofwallft2)3/8"Linerplate=3/8"x12=4.50in2/ftofwall3)2Layers811bardiagonalreinforcementat36"c/cconsideringonlythosebarsactingintension2x1.56x~2=1.47in2/ftofwall333ftFromTable1ofthisreportthemeanvalueofthereinforcementyield=49.8ksiandlinerplate=48.3ksiP=(5.33in2x49.8ksi)+(4.50in2x48.3ksi)+(1.47in2x49.8ksi)=265.4k+217.4k+73.2k=556.0kips/ft=46.33kips/inFromEq.1p=46,330lbs/in=67.1psi690>nInTable4canbefoundthlimitingpressurecapacityadjustedfortheassumptionofminimumspecifiedandminimumsampledmaterialpropertiesasdefinedinTable=l. 3.3PRESSURECAPACITYOFTHEEQUIPMENTHATCHCLOSURETheequipmenthatchclosuresusedontheD.CCookContainmentshavebeenidentified(Ref.l)aspotentiallylimitingthecapacityofthecontainmenttocarryinternalpressureloads.Thereasonsforthislimitationareidentifiedasfollows:1.Theendclosureisintheformofaflatplatehencepressureinducedloadingmustbecarriedbybendingratherthanmembraneshellaction.2.Aboltedspliceisusedinaregionofhighbendingmomentwhichmaylimitthecapacityofthehatchcovertocarrypressureload.3.Thefarspacedboltpatternandtherelativelylowrotational.stiffnessoftheequipmenthatchbarrelresultinlittlerotationalstiffnessorfixedendmomentcapacityoftheequipmenthatchcover-barrelattachment.Thisrequiresthatthehatchbeanalyzedessentiallyaspinconnected(allowedtorotate)ratherthanfixed(momentresistant)atitssupportstherebysignificantlyincreasingcenterspanmomentsinthehatchcover.BecauseofthepresenceoftheunsymmetricspliceandtheunsymmetricinsertionofthepersonnelhatchintotheequipmenthatchcoverasshowninFigure3theevaluationoftheequipmenthatchuniformpressurecapacitycannotbeperformedwithahighdegreeofaccuracywithoutrecoursetoafiniteelementformulation.Twosuchanalyseswereperformed,oneofthecoverplatespliceandtheotheroftheequipmenthatchcoverplateincludingtheeffectofthespliceandtheinsertedpersonnelhatchtodetermine.theirmaximuminternalpressurecarryingcapacities.~r3.3.1SplicePlatet1omentCaacity3.3.1.1HandCalculation-considering1"fullpenetrationwelddetailasshowninFigure4(1~BeforeproceedingtoareviewofthefiniteelementanalysisofthespliceplateshowninFigure4,ahandcalculationwasperformedinordertohaveabasisofcomparisonwiththemoredetailedfiniteelementcalculation(1)flotetheHarsteadreportneglectedtheweldgeometryinitscalculationofstresses. Given:SpliceasshowninFigure4-checksectionattopofweld(a)95-1"A-193Gr87boltsona224"lengthofsplice=2.38"spacingbetweenboltsontensionsideofspliceLimitingcapacityofspliceattopofweldisassumedatmeanyieldinoutermostfiberof2inchspliceplateontensionbolt,sideofspliceM2PL=sZ=(53.2ksi)1(2.38)(4)=84.41k-in/2.38in.ofspliceLimitedtensilecapacityofspliceplateTx=t'I~x=1o5in+T='M/1.5=S4.41/1.5=56.27kips/boltMgointT'jd=(56.27)x(2.5+4.0+1.875)=471.26k-in/2.38in.ofspliceMomentcapacity/inofsplice471.26/2.38=198.01k-in/inMomentcapacityof4"platewithoutspliceM4<<PL=sZ=53.2ksi(1)(1)16=141.87k-in/in<198.01~s.".4"plategovernsdesignCapacityofSplice=198.01]39,6of4"plate~87Checksectionatbaseofweld Limitingcapacityofspliceatbaseofweldisassumedatmeanyieldinoutermost.fiberof2inchspliceplateplus1"weld.(MinimumSpecifiedFoftheHeldmaterial=60.0Ksi)M2<<PL+1<~weld=sZ=(53.2Ksi)1(2.38)9=189.92K-in/2.38in.ofspliceLimitedtensilecapacityofsectionTx=M;x=2.5in.T=M/2.5=189.92/2.5=75.97Kips/boltSince75.97>56.27KipstopofweldlimitsdesignCheckcapacityofboltFromTable1MeanYieldof1"bolt=121.3KsiTensilearea1"bolt=0.605sq.in.Pyie]d=121.3x0.606=73.51Kips/bolt>56.27:.OK~

3.3.1.2FiniteElementAnalysisInFigure5isthefiniteelementmodeloftheequipmenthatchsplicejointshowingplateelements.UsingthecomputerprogramAtlSYSforanappliedmomenttothe4inchhatchcoverplateequaltoareferencecontainmentinternalpressureof40psi,.the.maximumoutermostfiberstressinthe2inchspliceplateis27.82ksiinelement76.Themaximumoutermostfiberstressinthefourinchplateisdeterminedas46.27ksiinelement145.Itappearsthereforethatthe4inchratherthan2inchplateatthejointcontrolsdesign.Thisisdueprimarilytotheweldwhichsignificantlyincreasestheeffectivethicknessofthespliceplateatitsconnectiontothefourinchplate.3.3.2EuimentHatchCoverPlatePressureCapacityInreference1Harsteaddeterminedtheequipmenthatchcapacityof53.0psiuniformpressureloadingbasedonsimplesupportboundaryconditionsofthecoverasauniform4"thickcircularplatehavingadiameterof19'-10".8ecauseoftheeffectoftheunsymmetricspliceandpersonnelhatchinsertafiniteelementanalysisoftheplateisperformed.AfinitelmentmodelingoftheplatewhichincludedthespliceisshowninFigure6.Thepersonnelhatchbecauseofitsrigidequiva'lent12"thicksupportringconnectiontotheequipmenthatchisassumedtotransmitonlyreactionloadsduetopressuretotheequipmenthatch.Thespliceismodeledasanequivalent12"x4"beamparallel,tothespliceandequaltothestiffnessofthefourinchplateacrossthesplice.UsingthecomputerprogramA"(SYSthemaximumstressintensityinthecoverplateisdterminedinelement95asshowninFigure7adjacenttothesplice.Theresultantlimitinginternalpressureloadatelement95is45.1psiforan"asbuilt"meanyieldstressof53.2ksiintheplate.FromSections3.3.1.1and3.3.1.2ofthisreportitisdeterminedthatthespliceplatehasagreatermomentcapacitythanthefourinchplate.ThelimitinginternalpressurecapacityoftheEquipmentHatchCoverPlateisthereforelimitedbythecapacityofthefourinchplateat45.1psi.InTable4canbefoundthelimitingpressurecapacityadjustedfortheassumptionofminimumspecifidandminimumsampledmaterialproperties.3'.4'RESSURECAPACITYOFPERSOiklELHATCH3.4.1EndPlateClosure HecauseoftheunsymmetricstiffeningofthepersonnelhatchcoverplateassnowninFigure8,afiniteelementanalysisoftheplateisperformedtodetermineitsinternalpressureretainingcapacity.Asinthecaseoftheequipmenthatchtheloadingfromthepersonnelhatchdooristransmittedtothepersonnelhatchclosureplateasareactionlineloadattheoointofsupport.Alsotheplateisconservativelyassumedsimplysupportedratherthanfixedendsupportedatitsconnectiontothepersonnelhatchbarrelbecauseoftherelativelowrotationalstiffnessofthebarrel.InFigure9isfoundthefiniteelementmodelofthehatchshowingallelements.TheplatandstiffnersystemisanalyzedusingthecomputerprogramAISYS.Themaximumoutermostfiberstressisdeterminedinthedoorstiffneratelement87as79.3ksiforarefrence70psiinternalpressureload.Thepressurecapacitypofthepersonnelhatchclosureisdetermined:p=70x53;2=47.0psi79.33.4.2DoorThepersonnelhatchdoorisshowninFigure8.Itactsessentiallyasaonewayspaningsimolysupportedstiffenedplate.Thetotalspanofthe1/2"tliickplateis42".Theplateisstiffenedby3"x1-1/4"solidplatestiffnersonapproximately15inchcenters.AssumingacompositeTsectionwiththeeffectiveoutstandingflangelegofteeequalto8timestheflangethickness,themomentofinertiaoftheTsectionis6.93in4anddistancestotheoutermostfibersofthesectionare1.03and2.47inchesrespectively.tlaximumappliedbendingmoment:)~i=1bp121(15)(p)(422)3307.5FHomentCapacityofStiffenOoorSection:H=sZ=(5,200)I=(53,200)6.93=149,261c22iTLimitinginternalpressurep=149,261=45.1psi3307.5 InTable4canbefoundthelimitingpressurecapacityadjustedfortheassumptionofminimumspecifiedandminimumsampledmaterialproperties.,4.0SUt"'u~'IARYAf'lDCONCLUSIOHFromthesummaryresultsoftheanalysispresentedinTable4itcanbeseenthatthecurrentlimitinginternalpressurecapacityoftheD.C.CookContainmentsaretheequipnenthatchclosureplateandtheequipmenthatchdoorat45.1psibasedontheuseofmean"asbuilt"materialproperties.ItshouldalsobepointedoutthatevenifspecifiedminimummaterialpropertieshadbeenusedaswasthecasereportedinRef.1byHarsteadtheminimumcapacityoftheD.C.Cook'Containmentis32.3psibasedonthemoredetailedanalysesreportedhereinratherthanthe23.5psireportedinRef.1whichwerebasedonmoreapproximatehandcalculations.Itshouldalsobeemphasizedthattheanalyticalassumptionusedinthemorerigorousanalysesreportedinthisstudyoftheequipmentandpersonnelhatcheswhoselimitingfailuremodeswereinbendingstillconsideredonlyelasticbehaviorandsectionproperties.Ithaslongbeenestablishedinthebehaviorofplateelementsduringtestandasthe'asisforthe1.5increaseinallowablebendingversusmenbranestresslimitsoftheASt<EBoilerandPressureVesselCodethatpl.ateandshellbendingelementsbehaveessentiallyelastic(smalldeformations)untiltheplasticsectionmodulusisreached.Sincetheplasticsectionmodulusforrectangularshapesassociatedwiththehatchplatesis1.5timestheelasticsectionmodulusthereissignificantadditionalsafetymargininthehatchanalysiswhichisnotapplicabletothemembraneorsheartypefailuremodesidentifiedinthecontainmentconcreteshellandbasemat.Toquantifytheeffectoftheplasticsectionmodulusoftheequipmenthatchontheinternalpressurecapacityofthecontainmentanon-linearelastic-plasticfiniteelementanalysisofthehatchcoverplateusingthecomputerProgramAf"SYSwasperformedfortheassumedfy=50.3Ksimaterialproperty.Evaluationat70psiinternalpressureor1.64timestheelasticcapacityofthecoverplateindicated.thatthemaximumdeflectionoftheplateisstilllinearandthemaximumplasticstrainwas1.8timestheelasticstrainatyield.ThereforeitisourconclusionthattheD.C.CookContainmentsaspresentlydesignedandconstructedconstituteabalanceddesign.Thatis,thetruepressureretainingcapacityofthehatcheswhenthe1.5factordiscussedpreviouslyisappliedisapproximatelythesameasthatoftheconcretelimitingportionofthecontainment,approximately54.5psi.OnthisbasiswedonotrecommendanymodificationoftheexistingD.C.Cook'ontainmenthatches. 00 Figure1O.C.CookContainmentOimensionsandGeneralArrangmentFigure2ShearFailurePlanesandGeneralArrangmentofReinforcementinthe8basematFigure3GeneralArrangmentoftheEquipmentHatchClosurePlateFigure4GeneralArrangmentoftheEquipmentHatchClosurePlateSpliceFigure5FiniteElement51odelofEquipmentHatchClosurePlateSpliceFigure6FiniteElementtlodeloftheEquipmentHatchClosurePlate'Figure7OetailedFiniteElementi~lodeoftheEquipmentHatchClosurePlateFigure8GeneralArrangementofthePrsonnelHatchClosure,PlateFigure9FiniteElementi'lodelofthePersonnelHatchClosurePlateTable2ComputerCalculatedResultantsForcesintheContainmentBaseSlabOue.toOeadl!eightTable3ComputerCalculatedResultantForcesintheContainmentBaseSlabOuetoaReference12.0psiInternalPressure TABLE1SU&iARYOFtiItfIMUNSPECIFIEDANDASBUILTMATERIALPROPERTIES1.LINERPLATE-SA442SAMPLESIZE=6S=2.27Cov.=0.0472.EgUIPMEiNTHATCH-SA516SAMPLESIZE=5S=2.74Cov.=0.051~GRADE60SPECIFIEDMINIMUt1MEANSAMPLEVALUESi~lINIf'lUMSAMPLEVALUESGRADE70SPECIFIEDMINIMUMi'lEAflSAtlPLEVALUESMIfIMUMSAiiPLEVALUESYIELD32.048.345.838.053.250.3ksiULTIMATE-60.064.762.470.081.280.23.e.5.BOLTING-SA193SAtiPLESIZE-2ea.1/2"x2-1/2"1"x5-1/2"(SPLICE)l-l/4"x10"(COVER)REINFORCINGRODA1518SSAMPLESIZE9S=3.34Cov.=0.067CONCRETE-28DAYSTRENGTH-SAMiPLESIZE29S=0.508Cov.=0.103GRADE87SPECIFIEDilINIi~lUMi~lEANSAMPLEVALUESSPECIFIEDMIiVIMUMi~iEAthSAMiPLEVALUES'PECIFIEDtlINIi~iUi~lflEANSAMPLEVALUESGRADE40SPECIFIEDtlINIMUMt1EANSAMPLEVALUESMINIMUMSAt'lPLEVALUESUflIT1and2SPECIFIEDt'lINIflUilflEANSAt'1PLEVALUESYINItlUtlSAMPLEVALUE105.0119.0105.0121.3105.0120.140.049.844.3125.0137.0125.0141.0125.0140.370.081.875.5'.54.9564.112 WV64VJI140~409~i999)]l0lll974~~ii0viSOLUTIONFUNCTIONSIHSYSTEttREFEREHCEFRAttfTable2ComputerCalculatedResultantesintheContainmentBaseSlabDuetoDeWeight10.207258K04R0.220710K0430.2340638K040.249031E0450.263875E0460.279153E0470.2940CEi50480.310?2'?E0490.32737"E04100.344161E04110.361263E040.00.00.00.00.00.00.00.00.00.00.00.179783E0.1816692E0.183450E0.185155K0.186704f0.188343E0.189335E0.191265K0.19263>>E0.193942K0.195193K040.834138E05040.548537K05040.243167E05040.8N924E04O4-O.42e949E0504-0.796689E0504-0.11C619E0604-0.159789E0604-0.20322lf0604-0.24S953K0604-0.29)069K06-0.120054E"DR0.00.148695C-OR0.00.414161K-020.00.675165E-OR0.00.9304051EDZ0,00~117869E-010.00.141846K-ol0.00~164i827E-Dl0'0.186456E-010.00.2071452-010.00.226201E-ol0.0-0.719304E-DR0.70479OE-OR-0'85N9E-02-0.64346.7E-020'36066K-DR-0.603897K-OR0.5646ii9E02-0.56200034'.E-02-0.4757042E-DR0.421537K-DR-0.361094K-0209163836.E030.16218iiE030.159343E-030.156762E030.152896E-030.148194"E-030.142618E-030.135108f-030.126616f-030.120092E-030.110472K-D3ACTUALSTRESSRESULTAIITS-SIIELLREFERENCEFRAtlf-BODY7%ATCEIITROIOcSTATIOtlCEIITROIOStlO;tlfRID~HOOPHllLB/IHtt12LB/IHH22LB/IN013LB/IHQ23LB/IHHllIH-LB/IHH12Itl-LB/IHtt22IH-LB/IN62.66262.BIIR62.86R62.811362.656.Sll62.85R62.811562.656262.811662.R6262.Cll762.8626".Sll0.179783E0.1S1662E0.183450K0.185155E0.166784E0.160>>343K0.189335K040.0040.0040.0040.0040.0040.0040.00.216753K0.216602E0.216593E0.216720E0.R16971E0.217339E0.217818E04-0.207258KQ4-0.220710K04-0.234638E04-0.N9031E04-0.626'3875E04-0.279153E04-0.2948iiE040.0040.0040.0040.0040.0040.0040.0-0.192634E05-0.488963f05-0.80454ioiE05-0.113994E06-0.149570E06-0~187235E06-0.227037E060.00.00900.00.00,0'~0060.0060.0060.0060.0862066R62.6110.1914"f040.00.218402E04-0.310929K040.0-0.269024K962.86262.8110.192634if040.00.219084K04-0.327378E040.0-0.313238E1060.06"610110;19W."E04"0;00:039060r04=0".344161E"04D.E-0.359717Ell62.86262.8110.195193E040.0-0.220726E04-0.361263E040.0-0.408547E00,189855E060~177062E060.163588E060,149402EOb0.134474E060.11877ef060.102285KOb0849739E050.668169E050.47793if050.278602K05STATIONLAYERHO.HO.1234567STRESSSllINSIDE0.14413K01-0.46754E02-0.1609iE-05-0.465i7E020.12971E01<<0.40609E02"0.13917E-050.13126E01-0.46667EOR-O.16O44E-O5-0.46276E020~1113CEol0403r59E02-0.13820K-050.00.00.00.00.00.00.00.00.00.00.00.00.00.0RESULTANTSTRESSES-PSIBOGYSSTRESSSllSTRESSS12STRESSS12OUTSIDEINSIDEOUTSIDESTRESSS22INSIDE0.36946K02I0.99142E-050.28696K030.9C645K-050~3>>4313K020.85744K050.24?obfD3STRESSS22OUTSIOE0.33971E020.98951E-050.28607E03093099E050.29374E020.85194K-050.24529E03

COOKPLAHTSOILPARAtlETERSTUDYtIO.1LOAOItlG3DEADIIEIGIIT312-30-80ComputerCalculated.ResultantForcesiContainmentBaseSlabDuetoaReferen.0psiInternalPressureSOLUTIOIIFUIICTIOIISIHSYSTEtiREFfREtlcEFRAtiE10.362819E20.300629E3O.R40632E40186rSZE50~126535E60.721415C70.19$453E8-0.319680E9-0.618996E10-0.13054ZEll-0.176029E040.0040.0040.004Q.o040.0030.0-030.0030.0030.0040.0040.00.12<i021E040.125169E040.126290E04012732rDE040.1"6295E040.129201E040.1300<>5E0<i0.13OGReEO40.1315<>?E040~132209f040~13261ZE040~197442E0.1477Z6E0.108624E0.600810E0.609194E0roQ246E0.493393E0560519E0.705932EO.926286C,0.121891E06"0.181325E0106-0.161004EOl06-0.180663EOl05-0.180361E01050.1600<>OE0105-0.179?RZE0105-0.179405E0105-0.179091E0105-0.178760E0105-0.1764i69E0106-0.178159E010.00.00.00.00.00.00.00.00.00.00.0-0.936208f-02-0.9>0639E-02-0.939061E-02-0.93292QE-OZ-0.923599E-02-O.912352E-02-0.90039<>E-02-0.866667E-02-0.878656E-02"0.871393E-OR-0.667<i6<iE-020.193628E-030195016E030195358E030.1'94910E-030.193908E-030.1925?GE-030.191125E-030.18975<IE-030.166653E-030.180003E"030.187975E-03ACTUALSTRESSRESULTAHTS-SIIELLREFEREtICEFRAtlE-BODY7/ATCEIITROIO<STATIOIICEHIROIDSHO.ttCRIO.IIOOPtillLG/IHOI'>LG/IHll22R13LB/IHLB/IHO23LG/IHtillIH-LG/IHti12.IH-LB/IHti22IH-LG/IH162.66262.811262.66262.611362.86262.61162.66262.611562.66262.811662.6626"..811762.662GZ.I>110~124021E040.00.125169E040.00.12629OE040.00.12735E0<i0.00.126295E040.00.129201E0<i0.00.13004.E0<i0.0862.652CR.GII0.13062of0<i0.0962.66262.6110.1515<i?C040.01062.CGZ62.8110.132209E0<i0.0ll62.66262.6110.13"612E0<i0.00.163855E0<>-0.362619E040.00.16391<>E04-0.30069E040.00.16320?E04-0.2<i0632E040.00.163539E04-0.162652C040.00163115E0<>-0.12653rSE040.00.1625<>if04-0.'/21<>15E030.00.1616"1C04-0.193<ir>3F030.00.16095?E040.3196QCE030.00.159956E040.81699GE030.0O.l'>:GZOE040.130542E040.00.157549L040~178029E040.00.126612E060.7622GOE050.3669?GC050.736369E04-0.123520E05"0.2296<i2E05-0.2<>9$14E050.00.00.00.00.00.00.0-0.166653E050.0-0.453569E040.001712"1E05000.460396E050.00.250910E060.236913E060.223955E060~212269E060.202044E060.193441E06.0.186555F0.161563E060.17652ZE060.177466E060.178462E06STATIOHLAYERIIO.IIO.STRESS511IH51DEREULTAHI'TRESSES-PSISTIIC55511Sll\L55SIROUTSJDEIl>SIDEBODY8STRESS512OUTSIDESTRESS522II>SIDESTRESS522OUTSIDE1235670.2<i416E01-0.73659E02-0.25338E-05-0.?319QE020.2)749E01-0.61216E02-0.20934E-050.22035EOl-0.73<i81E0202r5241E05-0.72691E020.18357EOl-0.60709E02-0.20738E-050.00.00.00.00.00.00.00.00.00.00.00.00.00.00.60108E020.15811E-040.457<ilE030.1571ZE"040.53466EOR0.131<ICE-040.37609E030.5419?E020~15773E-040.4556<if03015603E040.45064EOR0.13037E-040'7<>56E03

TABLE4SUf1NARYOFLIHITINGINTERNALUNIFORt1PRESSURECAPACITYOFD.C.COOKCONTAINMENTINTERNALPRESSURECAPACITY(ELASTICANALYSIS)(SeeSubsection4.0forPlasticAnalysis)CRITICALFAILURE110DESPECIFIEDMINItlUNPROPERTIESLOlJESTii/EASUREDSNlPLEPROPERTYMEANSAMPLEPROPERTYl.BendingShearingConcreteBaset1at2.MembraneHoopTensioninConcreteCylinder3.BendingCapacityofEquipmentHatch4.BendingCapacityofPersonnelHatch-(a)ClosurePlate(b)Doorfc=3500psl;fc=59.16Limitinginternalpressure=45.8psify=40,000psiLimitinginternalpressure=50.2psif>=38,000psiLimitinginternalpressure=32.3psify=38.000psiLimitinginternalpressure=33.6psiLimitinginternalpressure=32.3psifc=4100psi;fc=6403Limitinginternalpressure=49.6psif>=44,300psiLimitinginternalpressure=61.2psif>=50,300psiLimitinginternalpressure=42.6fy=50,300psiLimiting.internalpressure=44.4psiLimitinginternalpressure=42.6psifc=4950psi;fc=7036Limitinginternalpressure=54.5psify=49,800psiLimitinginternalpressure=67.1psify=53,200psiLimiting-internalpressure45.1fy=53,200psiLimitinginternalpressure=47.0psiLimitinginternalpressure=45.1psiNote:InternalPressureCapacitywherevernotedas"psi"means"Psig" CCNTAILlHEMTQlQllSTEELLILlEll>/b"THICKSPRlHGLlNIAZSTEELLINER>io'HICK~g~~'II5ŽID.STRELLIQIR>/Z'HICK<ms'~rGROUQOFL."~QRAOK4'lo"pBASEf1~ToPopMATleo'-0"OD~.GFCTtohJA-AGECTIQN4,LF.LEYATIQQFigure1D.C.CookContainmentDimensionsandGeneralArrangment .CL.F.c,.I~IAllL'I'.I7a~h\~4Sa,I,4$.TCHI~'nv0'r;CgC...l.Y=fi//vi.IiIll~T~+II~~5-~n.)lc~gl"I."IICI-"Is)=i]I.~5~~'Lvg77!w!!IggNdcc14I)-:)rCl~I<I~'p->I"4AjI'I-LCIl-IO'2A~~le."'.=vI'Pell'c)),'4IAtf+JLC~~5Av~Gse(cd~P.A><I3yQRI&poP,c)w~.NOT=1.iV:<~irL.ii;~Ni<W=.(r.=)<IVEIlT'3TnEC"=tIT"-RJFC3llTHNr-II.c~-=r.TA:.-II:.,T"-G.Figure2ShearFailurePlanesandGeneralArrangementofReinforcementintheContainmentBaseMat 5'-31'i'-t5YPh-32-!~/0"$HDLESON25O'I<"S.C.S4EQUALSPACES-BoLTS8+EQ0ALSppeES-..-SoLTS'.---~-~--------I=I0'-30'O-3/<"4HOLCS,ONl24"S.C.Figure3GeneralArrangmentoftheEquipmentHatchClosurePlate I]II)Ie~SI~~0~>(

<<)rLO<<%Oral<<~0~.I~5~4'F0514$145I~014014<<1%0I5I1%0)~0%Bot.TWal.bPIIOf:IIIL),It/It>I.ILCIt%ltklt)Ill%IIe<<)~l1~ClICTO5)SCSIItl10~5SSl~41010%OC5~CICt100I~I~5I~)5C5Cl~5<<55~)0%7<<g~iII~ClICt20)04~4~44$~5~1141%IItl~tlttt4~00-$.)l-4.15-4.Il-I~SC.<<.0$-5~)4tWC5100lhJOIST)Os4LVCIC0101140rOOCLI4)Ilt-.SleCIIltI))t)4CCOritev~v%1tIP)554IV4.v<<S~)0C.~004raaSLO)II>~~rI'1nltr.ElefnentHodelof'qulpmrntI%ItchClos>>rrI'intr'.Splice 31PREP7-PLOT34227337283831342474819565351/6e01212891121,4131411151221818853767,128138151515815,gfg~QiI16151?PREP?EPLTANSYSFigure6FiniteFlementModeloftheEquipmentHatchClosurePlate rgDI~SpealOF-'.21264o313312212142/1j'6125143156875128145154155Bc1291g1311301471481571562-~l"13213813914915815'52158161159160cotTANSY56Figure7DetailedFiniteElementMode(oftheEquipmentHatchClosurePlate /63/i"g!DEPTH(y/'"DEPTH.(YVP)~I$~9'lz"DEPTHPLsrrEIIP/pIT'oY'RwPEPTICi"PLATEP./7)rF'CWEAS3DEPTH~4~!TVP3~4~>Figure8GeneralArrangementofthePersonnelHatchClosurePlate

11172S916332982128147202'?1361926335323136393533373iQ12?4856314?5562046546120ea6915125182511417241031623QiS5360844525974351586<7167017691870.8-5'?.8-44.8-31.9-189-5'7.120.133.~46.0SQ0AlaLOCKPLAYPLAYSAtlALVSlsCEO?1ETRVANSYSFigure9FiniteElementModelofthePersonnelHatchClosurePlate

SECTION2PhaseIIoftheD.C.CookInternalPressureContainmentAnalsis-ProbabilisticAnalsisInthiseffortthevariabilityofthe"as-built"materialparametersonthebestestimatecapacityofthecontainmenttocarrystaticuniforminternalpressureisbeingevaluated.Fourpotentiallimitingfailuremodeshavebeenidentifiedbydeterministicanalysis.'woofthemodesinvolvepotentialfailurebyplatebendingoftheequip-mentandpersonnelhatchclosureplates.Theothertwopotentiallylimitingfailuremodesarebymembranetensionfailureofthemainsteelhoopreinforcementatthebaseof'hecontainmentshellandshear(diagonaltension)failureoftheconcretebasemet.TheACI-359Codeequationgoverningdiagonaltensionfailureisbasedontestresultshenceitisalsobeingevaluatedinaprobabilisticmanner.Resultsofthisstatisticalanalysiswillbeprobabilitydensityfunctionofcontainmentresistancedefinedforthetwodifferentcontain-ment"as-built"materialpropertiesandinthecaseofshearinthebasematthestatisticalnatureofthecodedefinedfailureequation.ThisevaluationshouldbecompletedbyMay15,1981.SECTION3PhaseIIIoftheD.C.CookInternalPressureContainmentAnalsis-LocalizeDnamicLoadsInthisevaluationdynamicanalyticalmodelsofthecontain-mentstructureassuminglocalizedynamicpressureloadinginputarebeingprepared.Thecontainmentareaswherethedynamicmodelsarebeingde-velopedincludetheequipmentandpersonnelhatchclosureplates,theshellportionofthecontainmentshelladjacenttothebasematandthebisematadjacenttothecylindershelljuncture.ThedevelopmentofthedynamicmodelsshouldbecompletebyMay30,1981.Thenusingtheinternalpressuretimehistoryforcingfunctions,adynamicanalysiswillbedonetodeterminetheforcesandmomentsatthecriticalsectionsofthecontainment.

DONALDC.COOKNUCLEARPLANTUNITNOS.tAND2ATTACHMENTNO.2TOAEP:NRC:00500ASECONDQUARTERLYREPORTONHYDROGENMITIGATIONANDCONTROL 0 2.0DistributedInitionSstem2.1IntroductionIndiana5MichiganElectricCompany(ISMECo.)hasdecidedtoinstallaDistributedIgnitionSystem(DIS)inUnitNos.1and2oftheDonaldC.CookNuclearPlant.TheDISutilizesthermalresistanceheatingelements(glowplugs)locatedthroughoutthecontainmentbuilding.OperationoftheDISwillbeaccomplishedbymeansofmanualcontrolswitcheslocatedinthemaincontrolroom.2.2DistributedInitionSstemDesinTheDISisatwo-trainsystememployingsixtyeight(68)igniterassemblieslocatedthroughoutthecontainmentbuilding.Eachtrainofthirtyfour(34)igniterassembliesisfurtherdividedintotwogroupsonegroupofsixteen(16)assembliesinthegenerallowervolumeareaandasecondgroupofeighteen(18)assembliesinthegeneraluppervolumearea-includingtheicecondenserupperplenumvolume.EachigniterassemblyconsistsofaGeneralMotorstype7GACglowplugandaDonganElectriccontrolpowertransformer(model52-20-435)mountedinasealedboxhousingasshowninFigure2.TheigniterboxisawatertightenclosuremeetingNEMA-4specifications.Acopperplateisemployedasaheatshieldtominimizetemperatureriseinsidetheigniterboxandadripshieldisutilizedtominimizedirectwaterimpingementonthethermalelement.Thetransformerisseismicallymountedtotheigniterboxusingunistrut.Theentireigniterassemblyisseismicallymountedsoastopreventanypossibleinterferenceswithsafety-relatedequipmentduring/afteradesignbasisseismicevent. ThenormalandemergencypowersourcesforeachtrainofignitersmeetsElectricalClasslEspecificationsandtheelectricaltrainseparationcriteriacommensuratewithaClass1EsystemaremaintainedintheDISdesign.TheDISwillbeamanualsystemcontrollablefromthemaincontrolroom.TwocontrolswitchespertrainwillbelocatedonauxiliaryrelaypanelsA7andA8inthemaincontrolroom.Thecontrolswitchesareofthetwo-positiontype,'off'nd'on',andredandgreenindicating.lightsareprovidedaboveeachswitch.Controlroomannunciationwillbeprovidedtoindicatelossofpowerandfailuretooperateduetohypotheticalcontrolcircuitequipmentmal:functions.2.3JIIAIAb1Theigniterassemblyisa16"x12"x8"enclosuremeetingNET-4specifications.Theigniterisprotectedfromdirectwaterimpingementbya1/8"steelplate(10"x18"galvanizedsteel)dripshieldweldedtothetopoftheenclosure.Theigniterismountedtotheenclosurethrougha6"x4"x1/4"copper,platetoreducethetemperaturerise.insidetheenclosureduring.periodsofcombustion.Allelectricalconnectionsinsidetheigniterassembly;itsassociatedconduletbox,andthetwospliceboxespertrainutilizedintheDISareprotectedwithheatshrinktubingtoenhancesystemperformanceinanadverseenvironment.Inaddition,allDIScablesinsidecontainmentareroutedinconduitandhenceareprotectedfromtheenvironmentassoci'atedwithhydrogencombustion.Accesstotheinterioroftheigniter'3assemblyisthroughahingedcoverplatesecuredwithscrews.Abeadofsiliconerubberwillbeplacedaroundallboltholesintheigniterassembly.DetailsoftheigniterassemblyanditsconduletboxaregiveninFigureNos.1and2. 2.4IniterAssemblLocationsIgniterassembliesaredistributedthroughoutthecontainmenttopromotecombustionofleanhydrogen/air/steammixtures.TheDISwillminimizethepotentialforhydrogenaccumulationandprecludedetonationsintheunlikelyeventofadegradedcorecoolingeventsimilarinnaturetotheTflI-2accidentinvolvingsubstantivehydrogengeneration.Thecontainmentairrecirculation/hydrogenskimmersystem,inconjunctionwithupperandlowervolumecontainmentsprays,providessufficientmixingsoastopreventthestratificationorpocketingofhydrogeninthevariouscompartmentsofthecontainmentbuilding.ApproximateigniterassemblylocationsarelistedinTable2-1.Ageneralviewof.thecontainmentstructureisprovidedinFigure3andapproximate~~~~~~~~~~~~~~~igniterlocationsshowninFigureNos.4,5and6.ThelocationsgivenareforD.C.CookUnitNo.2andaretypicalforUnitNo.1.'inor'.variations'nig-niterlocationsmayberequiredin.UnitiVo.1'inconsiderationofphysicalinter-ferenceswith.existingequipment.A'schematicrepresentationoftheDISelectricalnetworkinsidecontainmentisprovidedinFigureNos.7and8.OneofthequestionsraisedbymembersoftheNRCstaffduringourmeetingofMarch18,1981dealtwiththeneed,orlackthereof,toinstalligniterassembliesintheinstrument,room.todateindicatethatexceptforpotentialbetweentheinstrumentroomandeithertheTheresultsofourreviews.performedin-leakagethereisnocommunicatio'ngenerallowervolumeorthepipetunnel(annulusregion)withtheexceptionoftheflowpath-throughthehydrogenskimmerductwork. Theabovenotwithstanding,itshouldbenotedthatanyleakageintotheinstrumentroomwould,inallprobability,besignificantlylessthanthehydrogenskimmerflow(100CFt1pertrain)outoftheroom,thuspreventingItheaccumulationofhydrogentocombustiblelevels.Itshouldalsobenoted,thattheeffectsofhydrogencombustionon'required'quipmentlocatedintheinstrumentroom,pressurizerpressureandpressurizerleveltransmitters,is,forallintentsandpurposes,boundedbythecalculationscontainedinAttachmentNo.4ofthissubmittal. TABLE2-1IGNITERASSEMBLYLOCATIONS*Sheet1of2No.TRAIN'A'omartment/Area-ElevationNoTRAIN'B'omartment/Area-ElevationA-1A-2A-3A-6A-7A-8A-9A-10A-11A-12A-15A-16A-17A-18A-19A-20A-21A-22A-23A-24A-25A'-26A-27A-28A-29IceCond.UpperPlenumIceCond.UpperPlunumIceCond.UpperPlenumIceCond.UpperPlenumIceCond.UpperPlenumIceCond.UpperPlenumIceCond.UpperPlenumInside¹1SGEnclosureInside¹2SGEnclosureInside¹3SGEnclosureInside¹4SGEnclosureInsidePZREnclosureOutside¹1SGEnclosureOutside¹2SGEnclosureOutside¹3SGEnclosureOutside¹4SGEnclosureOutsidePZREnclosurePrimaryShieldWallPrimary.ShieldHallPrimaryShieldWallPrimaryShieldHallPrimaryShieldWallPrimaryShieldWallEastFan/AccumulatorRoomEastFan/AccumulatorRoomWestFan/AccumulatorRoomHestFan/AccumulatorRoomVicinityofPRTUpperVolumeDomeAreaUpperVolumeDomeArea708'09'09'09'09'10'09'86'86'86'86'686'59'662'62'62'62'47'48'648'48'41'48'31'29'34'18'60'60'-1B-2B-3B-4B-6B-7B-8B-9B-10B-11B-12B-13B-14B-15B-16B-17B-18B-19B-20B-21B-22B-23B-24B-25B-26B-27B-28B-29B-30IceCond.UpperPlenumIceCond.UpperPlenumIceCond.UpperPlenumIceCond.UpperPlenumIceCond.UpperPlenumIceCond.UpperPlenumIceCond.UpperPlenumInside¹1SGEnclosureInside¹2SGEnclosureInside¹3SGEnclosureInside¹4SGEnclosureInsidePZREnclosureOutside¹1SGEnclosureOutside¹2SGEnclosureOutside¹3SGEnclosureOutside¹4SGEnclosureOutsidePZREnclosurePrimaryShieldWallPrimaryShieldWallPrimaryShieldHallPrimaryShieldWallPrimaryShieldWallPrimaryShieldWallEastFan/AccumulatorRoomEastFan/AccumulatorRoomWestFan/AccumulatorRoomHestFan/AccumulatorRoomVicinityofPRTUpperVolumeDomeAreaUpperVolumeDomeArea709'09'09'09'09'09'09'86'86'86'85'82'62'59'59'59'59'42'37'36'36'37'45'30'29'23'34'18'60'60'

Sheet2of2Ho.TRAIN'A'omartment/Area-ElevationNo.TRAIN'B'omartment/Area-ElevationA-31A-32A-33A-34UpperVolumeDomeArea-760'pperVolumeDomeArea-748'pperVolumeDomeArea-748'pperVolumeDomeArea-748'-31B-32B-33B-34UpperVolumeDomeArea-760'pperVolumeDomeArea-748'pperVolumeDomeArea-748'pperVolumeDomeArea-748'EY:SG-SteamGeneratorPZR-PressurizerPRT-PressurizerReliefTanklocationsgivenareforDonaldC.CookUnitNo.2andaretypicalfor~~~~itNo.1.

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NIfiIPI"~p't7 AEP:NRC:0500A768'pperVolumePolarCrane715'pperePlenumI)@drogenRecombiner692'ceBedPressurizerLowerInletDoorsI(I(II1II'ZKf"1lSteamGenerators650'7"Lower.VolumeInstrumentRoomRecirculationFanPressurizerReliefTank4q>'rReactorYesselI',FIGURE3 Section'A-A'levation618FIGURE4gA-i<EastFan/AccumulatorRoomPr,imaryShieldHa'ilCraneHallIl9-IA10XiInstrumentRoomLO8-2>g~--A>+VE'.HestFan/AccumulatorRoom48-2WQ-i7QID.C.CookUnitNo.2Containment.PlanBelovedElevation652'7"PressurizerReliefTankTrain'B"IgniterTrain'A'gniter FI6~A-Z8-c.IceCondenserp~lO~p,t5g~gP/j/~+M/Q/D.C.CookUnitNo.2ContainmentPlanAboveElevation652'7"Train'B'gniteraTrain'A'gniter L~~ FIGURE50,PlatformElevation748'5"PlatformElevation759"32+33IIceCondenserTopDeckDoorsElevation715'.C.CookUnitHo.2ContainmentPlanAboveElevation715' 00 14IrtIIIIIIII4IIIIIII4I'IIII1IItI1II'I4~IIIII1I~I41I~IIIIII14'1tIi1i4I~II4~I'ti4i~I4II1'II-'4I1~~4I~I~'I'II!IIt111I4i4i~4I(~44~IIIIIfIIIIIII~IIIIIIIII.'I}'III'IIII~t!IIz7Bx4I4~jg'muzi!:Iiki7'L~~L.gIAZ~iQ~+ItI"4'1I1144I~~.~1'I4II~444441I~~III'II1~44l~~I4'II'~4f~I4'4I4I'4i4,1'}4I4iI44'I~~~f,'III+2Mzw&&U7-I1'~4~4tI~I~I'JI4~I1I'I~I1.-!4~,'(4',4~1I4III4I4!i*4'4'4Il~,~sI~.'~41~~,~4'IItI14~III~II~1I!IItII1~a~I4~~~4II~Ii;'4I4111II1II~1Itl'!I}I'iIII444~4I~I4iII'1IIIII~!}IIIIII;'4I}I4iIII~Is4II!~~t!I.IIIIii'iI~1,N~IIIII~I1III4I1II4i1IfIQII~I4tIIIi(IIIIIIII4II1/QIf/il441I~IIIii~14IIaII'II4x~mWAC2e~4I'441tt~'444I~t44~III~jkI4I1IIII~sI4tl4J~as~t44492-'ing~+71~'.4tIIi+(IWII}14IIiIIIa~41~t,~~~1I4-~4i1't441~I~it~~III*44~I~~fIII1'r4III1I*~}II'tI',III4II4II4-'4}Vat-='4w+~g4If~ts~I~441II444.1(.'I4ttettIIII4li~'I4ItI~IIIi~44II1III1IIIIIII(IIIIII~tII!1~I*aI'."}IIIII~~1I4I~JII41IIIIII6~AHsIIIkIII4II!I~'.~IIIi'II4~441III1~.II~}'IIeIII'i~.1I!I\.IIIIs1fI~4I~!III4II4I4IIkI!IIsI'14I11III1'I4I.II4sI"i:kII-I4f4~II';fi1~4-'II11i4*I4iIII4iJI4,t~.IIIti~444iI1i'II14"1k'.I!I4III~li~I'I','4Jk444414~~14s~Irv~EiddA.4~4(1k4:4'/T14IIIIIIIII'9aI4ItI's~41tP~~cfEAHLZIitIi11~II4~1iIeke~&44MMe4d~.~4I4I1~"'4-'4IIII4iI}iI!IIII"tIi~II.IIIIIIIiII4IIIII!IIIIIIII(I1'IIIIIIIIfI1II~4~I41~'4't4 4 'IcII1cIp1~1I~i~ItI'I~~~c1'icc1-1*r~1P',~1IIIItli,"icITI.~/~pgIt~III~chI1+cIcv.BE???:A&7&w7AJWvlt~IdC~i-cczxzemwII~III~rc~'I~IIII~~~Ig,cI1"/Q,ffIc~~tc'ItIII1II11-.1~iIccIS~vczw<WAX'~PfZ&7CPS-:2.+W~7ERBi~lil~II*ctcXA'/WANEE2Ã/~A>..rr?I[~i~~cc,i~c~wciIci)cjt--.~~-i+ItI~IL'-Li'c=-~~~~c=~c*.=v1'~cP8z....f/'I+'~v1+c~cI1.IliiMJP>'1'{~'OP{:*<<,I~~I~+gj~IIi"I'II~uIII,~1~.~o1IIr,If'Gq.a~PCII~~1IMPIIIIII*~~:::&E?I?ER?rt~~:CJR+EW:Cr??WRIER7/YEnZ7::YXFZe~im~RS:-.cde/.tlvI'~tItI*LZrr=Au'2CRa~~..rr&iHwWzd:NA'dmAl.z>-.~IIIV~;C~{?a;cInder~o.4;'507cz~MMJ&f',~IvI1t'1II~ccIi~j+4'J'. DONALDC.COOKNUCLEARPLANTUNITNOS.1AND2ATTACHMENTNO.3TOAEP:NRC:00500ASECONDQUARTERLYREPORTONHYDROGENMITIGATIONANDCONTROL

3.0InadeuateCoreCoolinHdroenControlEuiment3.1IntroductionTherearetwoprimaryconcernsassociatedwithaninadequatecorecooling(ICC)eventsimilartotheTMI-2accidentinvolvingthereleaseofsubstantiveamountsofhydrogenandsubsequentcombustionutilizingtheDistributedIgnitionSystem(DIS).Theseconcernsinvolve,(1)theabilitytoachieveandmaintainthereactorcoolantsysteminasafeshutdownconditionand(2)maintenanceofcontainmentintegritythroughadequatehydrogencontrol.Theequipmentlocatedinsidereactorcontainmentrequiredtoperformtheabovefunctionsisidentifiedinthissection.ThesurvivabilityoftheequipmentdiscussedhereinduringperiodsofhydrogencombustionisaddressedinAttachmentNo.4ofthissubmittal.ThecontainmentresponsetohydrogencombustioniscontainedinOffshorePowerSystem(OPS)ReportNo.36A05previouslytransmittedtotheCommissionasAttachmentNo.2toourfirstquarterlyreportonhydrogenissues(AEP:NRC:00500dated12January1981).TheanalysesperformedbyOPSutilizingtheCLASIXcomputercodeclearlyindicatethatthepeakpressureresultingfromhydrogencombustioniswellbelowtheultimatestrengthoftheCookPlantcontainments.3.2~EiEETable3-1liststheactivecomponentsinsidecontainmentrequiredtofunctionduringand(or)afterperiodsofhydrogencombustion.Thelocationofthesecomponentsandtheirsusceptibilitytohydrogencombustioneffectsareaddressedbelow.

(1)SteamGeneratorNarrow-RaneLevelMonitors.Threesafety-gradedifferentialpressuretransmitters(tLP)areemployedoneachsteamgeneratortomonitornarrow-rangesteamgeneratorwaterlevel.ThekPtransmitters,manufacturedbyITT8arton,arefullyqualifiedforpost-accidentuseinsidecontainment(LOCA/MSL8qualification).Thesetransmittersarelocatedinthegenerallowervolume,withtwotransmitterspersteamgeneratormountednearlyelevenfeetbelowthemaximumcontainmentfloodlevelof614'levation.ClasixrunJVAC4(seeAttachmentNo.2toourAEP:NRC:00500submittal-OPSReportNo.36A05)representstheminimumtimeto'ombustionfortheS2Dcasesruntodate.andhencerepresentsthecaseforwhichtheminimumcontainmentwaterlevelwouldexistatthetimeof'nitialcombustion.FigureNo.32oftheOPSreportshowstheinitialcombustiontooccurinthelowercompartmentapproximately4,600secondsintotheS2Deventsequence.Assumingthatwateristransferredtothecontainmentfromtherefuelingwaterstoragetank(RWST)solelyviatwocontainmentspraypumps,itiscle'arthattheminimumusableRl<STvolumespecifiedinthePlantTechnicalSpecifi-cations(350,000gallons)wouldhaveeffectivelybeendeliveredtothecontainmentpumplongbeforetheonsetofcombustion.Inaddition,theOPSreportshowsthatapproximately22.4XoftheinitialiceinventoryhasbeenmeltedduringtheLOTICportionoftheanalysis;uptoatimeof3480seconds.AssumingtheinitialiceinventorytobetheTechnicalSpecificationminimumvalueof2.37millionpounds; ~' itisthusshownthatinexcessof530,000poundsoficehasbeen.meltedpriortocombustion.Thisicemeltisequivalenttoapproxi-.mately.80,000gallonsofadditionalwaterinthecontainment.CombiningtheicemeltwiththeRl<STwateryieldsatotalcontainment"waterinventoryof430,000gallons,well-inexcessofthewaterinventorywhichwouldresultinsubmergenceoftwoleveltransmitterspersteamgenerator.Thus,itisclearthatthesteamgeneratornarrow-.rangelevelmonitoringfunctionwouldnotbesusceptibletotheeffects.ofahydrogencombustionenvironment.'(2)PressurizerPressureandPressurizerLevelMonitors-ThepressuretransmittersandthekPtransmittersutilizedfor.thepressurizer(PZR)pressureandlevelmonitoringfunctions,respectivelyarelocatedintheinstrumentroom.Thesetransmitters,-manufacturedbyITTBarton,arefullyqualifiedforpost-accidentuse-.insidecontainment(LOCA/MSLBqualification).AsstatedinSection'2.4ofAttachmentNo.2ofthissubmittal,ourreViewsperformedto'dateindicatethatthereisnocomnunicationbetweentheinstrumentroomandeitherlowercompartmentorthepipetunnel(annulusregion)-;otherthanthehydrogenskiomerductwork.Inaddition,theCLASIXH=analysesdonotpredictcombustioninthedead-endedvolume,ofwhichtheinstrumentroomisapart.Hence,theinformationavailableat-thistimeindicatesthatthePZRpressureandleveltransmitterswouldIInotbeexposedtoahydrogencombustionenvironmentintheunlikelyeventofadegradedcorecoolingeventinvolvingthegenerationofsubstantiveamountsofhydrogen. I~e (3(~333tll-33TTheRCSwide-rangepressuretransmittersarelocatedinthelo.rercompartmentnearlyelevenfeetbelowmaximumcontainmentflooduplevel.Thetransmitters,manufacturedbyITTBarton,arefullyqualifiedforpost-accidentuseinsidecontainment(LOCA/MSLBqualifi-cation).ForreasonssetforthinItem(1)above,thesetransmitterswouldbesubmergedpriortoinitiation'fcombustionandhencewouldnotbeexposedtoahydrogencombustionenvironmentintheunlikelyeventofadegradedcorecoolingeventinvolvingthegenerationof,substantiveamountsofhydrogen.(4)CoreExitThermocoulesTheeffectsofahydrogencombustionenvironmentonthecore-exitthermocouplecableisaddressedinAttachmentNo.4tothissubmittal.(Ri~RCS(RTThehotlegandcoldlegRTQs,locatedinthelowercompartment,-arefullyqualifiedforpost-accidentuse(LOCA/MSLBqualification).3ThecableassociatedwiththeRTDsisaddressedinAttachmentNo.4tothissubmittal.tl=(6)AirRecirculationHdroenSkimmerFans('heairrecirculation/hydrogenskimmerfansarelocatedintheuppe~cd.,partmentandthePanmotorsarefullyqualifiedforpost-accidentuse'(LOCA/MSLBqualification).(7).DistributedInitionSstemDISComonentsTheDIScomponentsinsidecontainmentaretheigniterassemblies;spliceboxesandconduletboxes,andtheancillarycable.AllDIScableinsidecontainmentisroutedinconduitandthusisprotected

.fromahydrogenburn.Allelectricalconnectionsinsidetheigniter.assembly,itsassociatedconduletbox,andthetwospliceboxespertrainutilizedintheDISareprotectedwithheatshrinktubingto.enhancesystemperformanceinanadverseenvironment.TheigniterassemblyitselfisasealedenclosuremeetingNEMA-4specifications.h

.Table3-1,;DonaldC.CookNuclearPlarltUnitNos.1and2.InadeuateCoreCoolin/HdroqenControlEuiment*-{1,)',Narrow-rangeSteamGeneratorLevelMonitors.(2)PressurizerLevelMonitors{3)PressurizerPressureMonitors-':(4)RCSWide-RangePressureMonitors-.:{5):CoreExitThermocouples-{6)RCSLoopsRTDs--{7)AirRecirculation/HydrogenSkimmerFans=-.(8)DistributedIgnitionSystemComponents*insidereactorcontainment

DONALDC.COOKNUCLEARPLANTUNITNOS.1AND2ATTACHMENTNO.4TOAEP:NRC:00500ASECONDQUARTERLYREPORTONHYDROGENMITIGATIONAADCONTROL 4.0EuimentSurvivabilitThisattachmenttothequarterlyreportaddressestheissueofthesurvivabilityofequipmentexposedtoahydrogencombustionatmosphereinsidecontainment.Heat-transfermodelshavebeendevelopedtodeterminetheeffectsofhydrogenburnsoncriticalcomponents(seeTable3-1inAttachment3).Themodelsarepresentedinthisattachmentfollowedbyacalculationmadeforarepresentativepieceofequipment.Particularattentionhasbeendevotedtoanumberofindividualpiecesofequipment,eachofwhichisdiscussedseparately.4.1~G1AInordertocharacterizetheenvironmenttowhichapieceofcritical~~~equipmentissubjectedduringandsubsequenttoahydrogenburn,twoheat-transfermodelshavebeendeveloped.Thefirstheat-transfermodelisatimedependentheat-transferanalysiswhichcalculatesthelowercompartmentenviron-mentasaresultofahydrogenburn.Thismodeltakesintoaccountthepresenceofstructuralheatsinksandspraysinthelowercompartmentandassumesthatduringahydrogenburnenergyisremovedbytheicecondenser.Theburnitselfismodelledbyanenergyinputratetothecompartment.Attheonsetofthecombustion,thelowercompartmentisassumedtobeisothermal;energyisthenintroducedintothecompartmentforadurationof20seconds,comparabletothetimeofahydrogenburninthecontainment.Asaresultoftheburn,thetemperatureofthecompartmentatmospherebeginstoriserapidly;concurrently,heatisbeingtransferredtothestructuralheatsinksandremovedbytheicecondenserandby)helowercompartmentsprays.Heattransfertothecontainmentsinksischaracterizedbybothconvectionand

radiation.Conservativeassumptionshavebeenmadeinthecalculationwithregardtoparameterssuchasgasemissivityandconfigurationfactors.~~After20seconds,theatmospheretemperatureisobservedtodecreaseexponentially,whereasthecontainmentwalltemperaturecontinuestoriseoverthenexttwentyseconds(seeFigure4-1)untilthetimewhentheatmospheretemperaturefallsbelowthewalltemperature.Themaximumatmos-pheretemperaturecalculateddoesnotexceed500F.SensitivitystudiesofvariousparametersusedintheanalysisarepresentedinFigures4-2and4-3.Figure4-2depictstheresultsobtainedwhentheheattransfercoefficient,"h",fromatmospheretowallisvaried;as"h"vanishes,thepeakatmospheretemperatureapproachestheCLASIXresults.Itcanalsobenotedthat,ingeneral,thepeaktemperatureisfairlyinsensitivetosmallvariationsinthevaluesoftheheattransfercoefficientchosen.Perturbationsinthesprayflowratealsorevealsmallincreases(n15Ã)inthepeaktemperature,seeFigure4-3.Theseanalysesclearlyshowthatifcontainmentstructuralheatsinksareconsidered,thecontainmentenvironmentisnotexpectedtoexperiencetemperaturesinexcessof500F.Theequipmentincludedinthecriticallistofcomponents(Table3-1)isqualifiedforLOCAandMSLBevents;whichincludesexposureto340Fforaperiodinexcessofonehour.ComparisonbetweentheMSLBconditionsandthedatapresentedinFigure4-1indicatesthatequipment,whichis'subjdctedPtoahydrogenburnofthemagnitudepredictedbyCLASIX,will*experienceenvironmentalconditionsnomoreseverethanthoseofaMSLBevent.Thesecondheat-transfermodelattemptstodescribeanddefinetheenvironmentalconditionsforequipmentwhichislocatedinthepathtraversedbythehydrogenflame.ABartonpressuretransmitterhas.beenselectedasarepresentativepieceofequipmenttobeinvestigated. Priortohydrogenignition,thetransmittercasinganditsinternalsareassuredtobeinthermalequilibriumwiththecontainmentenvironment.Attheonsetofahydrogenburn,itispostulatedthatignitionoccursin-thevicinityofthetransmitterandthecasingissubjectedtoaveryhighhydrogenflametemperature(~2000F)initiallyastheflamefrontmovesawayfromthecomponent.Thetemperaturetowhichthetransmittersurfaceisexposedwillthendecreasegraduallyandwilleventuallyapproachlong-timeresultscalculatedbythepreviousheat-transfermodel.Thistemperatureprofilewillprovidetheoutsideboundaryconditionneededtoevaluatethetemperatureriseontheinsidesurfaceofthetransmitter.Theone-dimension.time-dependentconductionheattransferequationisevaluatedassumingthattheinsidesurface-isanadiabaticboundary.Thismodeltreatsthetrans--.mittercasingasaone-dimensionalslab.Thetimedependenttemperature'profiletobeusedontheoutsidesurfaceisimposedasaconvectiveboundarycondition.Twodifferenttemperatureprofiles,whichreflecttheenvironmenttemperaturetowhichthetransmitterisexposed,havebeenemployedinthiscalculation.Thefirstprofilerepresentsahydrogenflametemperatureof'2000Fforadurationofonesecondattheonsetpriortoalineardecayto-1000Finthenextsecond;temperaturecontinuestodecreaseto300Ffromtwotosixsecondsandeventuallyapproaches150Fafter10seconds(seeFigure4-4),curveA.ThistemperatureprofileissimilartotheoneusedbyTVAinitsequipmentsurvivabilitycalculations.Theotherprofile,seeFigure4-4,curve8,decaysexponentiallyfrom2000Fto150Foveraperiodof18secondsandissimilartotheoneusedintheDukeanalysis.Acomputercodewasusedtoanalyzethetemperatureriseina1/4"carbonsteelcasinggiventheaforementionedboundaryconditions.Theheattransfercoefficientassumedinthecodeincludesbothconvectiveandradiativetransport. 0 ThetemperaturetransientsattheinsidesurfacecalculatedfromthetwotemperatureprofilesaredepictedinFigure4-5.Curve(A)ofFigure4-5,-whichcorrespondstothecurve.AofFigure4-4,showedthattheinitial-temperatureriseisveryabruptduringthefirstfewseconds;laterontheinsidesurfacereachesamaximumtemperatureof171Fat10secondspriortoagradualdecrease.Thetemperatureresponsedepictedbycurve(B)of.Figure4-5indicates.thatthereisamoregradualriseovertheinitial15secondsandthatthetemperaturereachesitsmaximumof175Fatabout30secondsbeforeaslowdecaybegins.Basedonthisanalysis,onecanassumethatforasinglehydrogenburn,theinsidecasingtemperaturewillrisenomorethan30F..Additionally,ifoneassumesthatthereisatotalofeightconsecutiveburnsandthatbetweeneachburntheinsidecasingsurfacetemperatureisheldconstant,thetemperatureprofilewillbeastepwisefunctionsimilartotheonepresentedinFigure4-6.Eachtemperatureincrease(30oF.)canbeinterpretedastheheatupofthecasingresultingfromonehydrogenburn.Betweeneachburn,thetemperatureIattheinsidecasingisassumedtobeconstantwhichimpliesthatnocreditisgiventothecoolingofthecomponentsubsequenttoanyburn.Inaddition,thetimeintervalbetweencombustionsisassumedtobesubstantiallyshorter'thanwhatispredictedbyCLASIX;only100secondintervalsareusedinthiscalculation.Basedonthestepwisecurve,aconservativelinearheatuptemperatureprofileattheinsidesurfaceofthecasingisused,seeFigure4-6.Utilizingthislineartemperatureresponseattheinsideofthetrans-~mittercasing,aheattransferanalysishasbeenperformedto'evaluatetheheatuprateoftheairandthesubcomponentsinsidethecasing.Results indicatethattheheatuprateoftheairinsideisslightlybelowthetemperatureofthecasingandthattheheatuprateofthesubcomponentsisestimatedtobeapproximately50Foversevenburns,or,7Fperburn..Itisimportanttobearinmindthatconservativeassumptionshavebeen.usedinobtainingtheaboveresults.The.heattransferanalysisclearlyindicatesthatformostequipment-.whichisenvironmentally.qualifiedforLOCAorHSLBevents,elevatedtemperaturesresultedfromhydrogenburnsofthemagnitudeandduration:.discusseddonotappeartoposeanythreattoitsabilitytosurviveina=~2D,-typeevent.-4e2SurvivabilitofParticularPiecesofEuiments~~ThissectionofAttachment4discussesthesurvivabilityofparticular-:piecesofequipmentneededforthemitigationandcontrolofaS2D-typesequence.Thesepiecesofequipmentrequireeitherparticularevaluationsor,else,theanalysispresentedinSection4.1doesnotapplytothem..a)Cables'-TheburningofhydrogeninsidecontainmentbyuseofaDistributedIgnitionSystem(DIS)resultsinveryshortdurationexposurefiresandmay-involvecableswhichareexposedintrays.InsidetheCookcontainmentbuildingspowerandcontrolcablesare-eitherinstalledinconduitsorincabletrays.Cablesinstalledinconduitsarenotlikelytoburnasaresultofexposuretoshort-durationexposurefires.Thesecablescannotpropagatea-fireeveniftheyburnsincetheflameresultingfromthe.combustionis-entirelyconfinedtotheconduitandcannotcausefailureofcables~~~~inadjacentenclosures. -Inthecaseofthecontrolcableswherethecurrentcarriedbytheconductorsissmallrelativetothethermalratingoftheconductors,.thecablesareinstalledintrayswithsolidsteelsides,bottomsandcovers..Hence,itisnotlikelyforahydrogenburninsidecontainmenttoigniteanycontrolcablesinstalledintrays.However,uponexitingatray,eithermid-spanthroughaholeinthetraycoverorattheendofthetrayspan,aportionofthecablebecomesexposedforaveryshortlengthuntilthecableseitherenteraconduitwhichfacilitatesentryintoterminaldevices.oruntilthecablesareconnectedtothedeviceorcontainmentpenetration:,(belowfloodlevel)..Allcontrolcablesinsidecontainmentneededforinadequatecorecoolingmitigationequipmentarequalifiedforflameresistanceinaccordance.:witheitherIPCEAStandardS-19-81orIEEE-383.Hence,fortheexposedportions:ofthecontrolcablesandcablesentirelycontainedintraysorconduits,itisextremelylikelythatthecableswillsurvivehydrogenburnsinsidecontain-sment.Furthermore,thecablewillbewetduetotheactuationofcontainmentspraysmakingthepossibilityofignitionfromashortdurationexposureto,fireevenmorer'emote.Forthecaseofpowercables,theyareinstalledinconduitsorin-expandedmetaltrayswithoutcoversandaresizedtoaccommodatethefull.loadcurrentofconnectedequipmentwithoutexceedingtheircontinuousrated.temperature.1Jheninstalledinexpandedmetalcabletrays,'hecablesarelaidtypicallyonelayerdeepwithspacesbetweenadjacentcablesandsecuredtothebottomofthetraytomaintainthisspacing.ThepowercablesforICC'equipmentmaybeexposedtohydrogenburninginsidecontainmentbuttheyare qualifiedforflameresistanceinaccordancewithIEEE-383orS-19-81.Further,sincethepowercablesareexposed(opentrays)theywillbewetduetotheeffectofcontainmentsprays.TestingresultshavebeenreportedbyL.J.KlamerusofSandiaonIEEE-383cables.PrivatecommunicationwithNr.KlamerusrevealedthatthecablesusedintheexperimentwereX-linkpolyethylenecables.Theywereselectedf'rthetestbecausetheywerebelievedtobemostsusceptibletoexposurefi.refailure.Reportedresultsindicatethatthetimetoelectricalshortforthesecablesrangesfromfivetonineminutes.ReviewofICCequipmentpowercablesatCookconfirmsthefactthattheyareeitherinsulatedbygpalonorasyntheticcompoundmadebyKerite.BothtypesofmaterialsarebelievedtoexhibitsuperiorfireresistingcapabilitythanthosetestedbySandiaLaboratory.Therefore,despitethefactthatpowercablesatCookmightbeexposedtoatwotothreeminutestotaldurationofhydrogenburnsexperimentalevidencesupportthecontentionthatitisverylikelythattheywillbeabletosurvivehydrogenburnstypicalofthosediscussedforaS2D-typeevent.b)AirRecirculationFansTherearetwoairrecirculationfansatCookandbothofthemarelocatedintheuppercompartment.Thesetwocentri,fugalfanshaveatotalcapacityof80,000cfmanddischargetheflowintothetwofan/accumulatorrooms.Attheexitofeachfanthereisabackdropdamperwhichopensasaresultofflowthroughthefan.Thedamperisgravityloadedandisexpectedtocloseifthereisan"overpressureinthefan/accumulatorroom.TheCLASIXresultspredictburnsintheuppercompartmentwithpressuredifferentials 1b unaccountedforinthedesignofthesystem.Fanintegrityisbeingevaluatedbothfromthepointofviewofcasingdamageandoverspeeding-ofthewheelandmotor.c)SteamInertinandPolurethane.InsulationBurnInaSD-typeevent,hydrogenreleasebeginsapproximately3800secondsaftertheonsetofasmallbreak.ResultsobtainedfromtheMarchcodeforSequoyahindicatethatduringtheinitial700seconds,thesteamcon'centrationatthelowercompartmentreachesamaximumof78/priortodecayingto45/,seeFigure4-7.Subsequently,thesteamconcentration-continuestodecreasetoapproximately25/atonsetofthehydrogenrelease.DatareportedbytheU.S.BureauofNinesindicatethatlittlechange.tothelowerflammabilitylimitofhydrogenisnotedwhensteamconcentrationinthemixtureiskeptbelow308.Therefore,witha254steamconcentration-inthelowercompartment,theeffectsofsteamuponhydrogencombustionshouldbeminimal.'oreover,lowercompartmentspraysatCookwouldfurtherservetoenhancecondensationofsteamandtopromoterapidtemperaturereductioninthe.lowercompartment.Thus,itisexpectedthatthesteamconcentrationintheCooklowercompartmentwillbesubstantiallylowerthan.whathasbeenpresentedinFigure4-7.Therefore,itisunlikelythatCookwillexperiencesteam.inertinginaS2D-likeeventexceptpossiblyduringtheinitial1000seconds.Inaddition,datapresentedbyLawrenceLivermoreLaboratoryintheirignitertestprogramclearlyshowthatsteamconcentrationsupto40Ãdonotinhibittheignitionofhydrogenbytheglowplugsnortheabilityoftheigniterstofunctionasdesigned.Inspiteofthefactthattherewouldbeahighersteamconcentrationinthelowercompartment,evidenceindicates1

.thattheglowplugigniterswillperformtheirintendedfunctionsas~~~~-required.Itisconceivablethatattheupperplenumofice-condenser,a:higherhydrogenconcentrationmaybepresentasaresultofsteamstrippingbytheicecondenser.Ithasalsobeenpostulatedthatcombustionmayfirst-occuratthatlocationandthatitmayevenburninacontinuousmanner.However,itmustbepointedoutthatthelikelihoodoftheabovescenario=diminishesiftheassumptiononsteaminertingatthelowercompartmentisconsideredunrealistic.Giventhecomplexityofthisissue,thequestionofburninginthe.upperplenumoftheicecondenserwillcontinuetobeinvestigatedbyAEP.'Moreover,upcomingresultsfromthemodifiedversionofCLASIXshouldbeabletoprovideadditionalinformationonthissubject.Ifhydrogencombustionis-assumedtooccurattheupperplenumforanextendedperiodoftime,ithasbeenpostulatedthattheintegrityofthepolyurethaneinsulationmaybethreatenedbythepresenceofhotgases.Thisquestionisbeingaddressed-atAEPsimultaneouslywiththeupperplenumburnissue.TheresultsofourevaluationswillbetransmittedtotheNRCinthenextquarterlyreport. 0 4-.4~~=I~~~-.l~~~=4~~~~~\44~i-i44~'4=-4I444~-444~4~44~4~LON3~C.<i'!"-,-'kg44I4~=1'I4l44j"'pFt-5c4&-4I44':.ahk:kkkjki~.--.4=-4.4:-=-=.~4~=-~4-4kX'4tpk($QQ)FIGURE4-1TEYiPERATURERESPOi(SESOFLOMERCGlk1PARTHENTATi)OSPHEREANOMALL/ ,-Jooo.~-1ii.jit-l'0--.tjOo-I'i-~t~tI~ItIIi~jr'!ti"""'T"!e~!t~I)~~!,.1!l.,'t~~It~~~=-I~>>it~~~Ii~Ia1as~1~tI~<<~~~I~~wIIV1itIi-I1~jtIII-I41...>>Jji-!-!Lj0:;!!!1Tj:I-C~r~>XTPi=SRI'~!Ij--fk1/l.I;t..11T'JI,'".'~ijatjjIi~-~LI:,IL!1!Ij.-0II~~Ej1iI!j~-II,k!Ijkj~I~tjI1I-1II=~tI:1!I',!,1I1i;',I<<i',FIGUREI1-1!~Iift>>I'IIII1It1~tT-l~III'i.t'1I11lII!!HEISTVRI!NSFR.COhF-FICieJTI'I>>IT>>I>>'.(I'I/j',.):;i'-2EFFECTSOF!IEATTRANSFERCOEFFICIENTYARIATIONSONt1AXIt1UMATMOSPHERETEt1PERATURE'NLOWERCOt1PARTt1EttT 'lk"r.(0->>jI>>-I~-~-Tt...LLaEt~f~If>>~Ct-.t-lt:I-fi!fj~trrr't.jt,.ti),~~($qillIIIIII!!(UoI(i+pQQ/,P!I(QgQ,r(r/SIC)>>>>I>,r'rrrt,i'-('IFIGURE",4-'3,EFFECTSOFSPRAYFLO>>'tRATEVARIATIONSONPEAKILILLLIl(iATNoSPHERETENERATUREINLO((ER,CONPA(ITNENT3!Ifttj1I 4iII+'.I.4~4=t-4tII44~=~~'\it~4.I'44~I4I=*t~I4~~t-~==444EM-:-':=3'*4*'I~-,-~~+:==+4*444ftt-Jm~-~-~~M444~~~*~l4>>=44=-+II~t=.4.l*~l~t~.j~=-~-~~-.-=-.~--t-s.-~J..~tt~-~-4-~.XE.~.4='-~!tt~tW+~~~4-I~+l4j3(2~tt4~f4<<tIIll~4~I*-J-~~4I4>>*444~*I444l444~~t4~=~4f-'4-~~'-l~l-4-~>>~4~*~i~~}=-I4}t~~J'!';~I+'13t4I4I~>>~CItt4200t*~IIt-~=~'I~4-~4~=I34t~}irF>>flan.~t-<<4>>-t.<<I-FiGURE-'tf-}}.-'TEMPERATUREPROFILESUSED-ASCONVECTIVE,:.BOUNDARYCONDITIONS

0 4h4III44I~~I4:.4~--~~~44il'=~:"14I-I=I-~~-=-41-I.~4~~r'IASSU11EDINSIDESORFACE-TEMPERATUREPROFILES=r~44~

VI1I)1!IiI~1Itfjff4j!IIt>i~IQQ'.;~I:&,.'~I,1~~~f'II.'gag<<I.III!~a4o~I~~!Ir'>>~.e'.-t~~~~~I<<t.aI~>~j4~~~l~-j>')',~/ljf1f=t"tIi.'it')!vIIV'r-j!LOT<<V.".Rfffd<<'Ia-ha)j',I-J->J;I\441l'~g0'OfACg,C-0f'~tP/.',PTg,"(O'T~P~%/~I'j1f.,<~O";l.<<"-!!,Iff~if-4v:l[J'fl'jjr4ar.~AT!'-:3Fa1p*,RE:<<j-ONSef..o-1iBASE=j-tl.)jt~~~~~Q.>>-"~'ljt-~>1.'1t.,"<<'.i~!;--2-o-'-~~~~*Ij-tl'~a!I!!!Ilj'4!~afi41'tl"l~1'IIII,:illk-A,Ittf;JJ..'>~(jl.tfLLX-l~1IT[:t.lf-f<<'1tl)j"-tj:-,i:.~IL0l4ER.;!~i:li<<I-:lIItlll.ij!,.I1!II!!j'}-IQjh(pMTt.~~lL'i4'1ji,;illtI~.0;4IIi~Il~fII~~~I,~1rl41~I~~il->11l~I~~~-tIijKO'0'0I",FIGURE4-ilII4I,O.t,.DaÃ;1ll;Qt-0f;l):WOO7STEANCONCENTRATIONINLOWER<l',C011PARTt1EfNTASAFUNCTIONOFTIt1Ejla11I14+me!','!'(2c.),'

References:

(1)Klamerus,L.J.,"FireProtectionResearch,"quarterlyProgressReport,October-December1977,NUREG/CR-0366.(2)PrivateCommunication,L.J.KlamerustoK.K.Shiu,March1981.(3)Hertzberg,M.,"FlammabilityLimitsandPressureDevelopmentinH2-AirMixtures,"U.S.BureauofMines,PRCReportNo.4305,January1981.(4)Lowry,W.,"PreliminaryResultsofThermalIgniterExperimentsinH2-AirSteamEnvironments,"PaperpresentedattheworkshopontheimpactofHydrogenonWaterReactorSafety,Albuquerque,NewMexico,January1981.(5)SequoyahNuclearPlant,CoreDegradationProgram,Yolume2,ReportontheSafetyEvaluationoftheIDIS,December15,1980. 00 DONALDC.COOKNUCLEARPLANTUNITNOS.1AND2ATTACNENTNO.5TOAEP:NRC:00500ASECONDQUARTERLYREPORTONHYDROGENMITIGATIONANDCONTROL

5.0CurrentResearchProramsSeveralresearchprogramshavebeenundertakenbyAEPtoinvestigatehydrogencontrolrelatedphenomena;someoftheseprogramswerediscussedinthelastquarterlyreport.Inthissectionanumberofthecurrentresearchprogramswillbereviewed;programstatus,revisedtestplanandprogramscheduleofeacheffortwillbediscussedindividually.~RPRIPAEP.,alongwithDukeandTYA,areco-sponsorsoff'ourEPRIresearchprogramsinwhichfundamentalflamestudieswi11bemade;researchanddevelopmentonvariousignitertypeswillbepursued;mixinganddistributionofhydrogeninprototypiccontainmentenvironmentswillbeinvestigatedandadditionalglowplugtestingwillbeperformed.a)MhiteshellNuclearResearchEstablishmentThisresearchfacilityisoperatedby'AtomicEnergyofCanadaLimited.Tworesearchprogramswillbepursuedindependentlyatthisfacility;namely,thehydrogencombustionphenomenastudyandtheresearchanddevelopmentofdifferentignitertypes.BothoftheseprogramswillbeundertakenwiththecollaborationofOntarioHydroasanadditionalfinancialcontributortothework.IThefirstexperimentalprogramisdesignedtoinvestigatevarioushydrogencombustionphenomenaandcan'bedividedintofourparts.Thefirstpartofthisexperimentaleffortentailsperformingnineteenignitiontestsonleanhydrogenmixtures.Thehydrogenconcentrationtobeexaminedinthesetestswillvaryfrom5.05to30Ãbyvolume.Asparkignitionsourcewhichis

intheorderof0.5joulewillbeusedtoignitethemixture.Detailsoftheexperimentalsetupandtestvesseldimensionshavebeenpresentedinthepreviousquarterlysubmittal.Fastresponsepressuretransducers,thermo-couplesandionizationprobeswillbeemployedtomonitorandrecordvariousimportanttestparameters.Ofthe=nineteentestsplannedthemajorityofthemwillbeconductedwiththeignitionsparklocatednearthebottomofthesphericaltestvessel.Twotestsareplannedinwhichtheignitionsourcewillbelocatedatthecenterofthevesselandonetestisplannedwiththeignitionsourcenearthetopofthevessel.Thesethreetestswillbeusedtoassesstheeffectofigniterlocation.Thesetestsareanticipatedtorequireapproximatelythreeweekstocomplete.AccordingtothelatestestimateprovidedbyHNRE,systemshakedownisbeingperformedonthetestvesselandonthedataacquisitionsystem;itisexpectedthatdatacollectionwillbeginbyarlyNay.PartIIofthehydrogencombustionprogramincludesatotalofIIeighteentestswhichareintendedtostudysphericaldeflagrationsofahydrogenflame.Thehydrogenconcentrationsthatwillbeinvestigatedrangefrom105to42Kwhereasthesteamconcentrationswillvaryfrom0to30Ã.Withtheexceptionoftwotestsinwhichignitionwillbeinitiatedatthebottomofthetestvesselalltestswillbeperformedusingcenterignition.The'timerequiredtocompletethesetestsisapproximatelyonemonth.IISubsequenttotheseteststhetestvesselwillbemodifiedforthestudyofturbulenteffectsonhydrogencombustion.Twoweekshavebeenscheduledintheprogramplantoaccomplishthesemodifications. TheprimaryobjectiveofthePartIIItestsistoinvestigateturbulenteffectsuponcompletenessofhydrogenburns,anduponpressureandtemperatureresponses.Turbulenceinthesetestswillbecreatedbytwodifferentmeans:1)two16"diametervaniablespeedfansand,2)gratings.Thefansareratedat1500cfmeachandconsequentlyarecapableofcreatingaveryturbulentenvironment.Thegratingsaremadeof1/4"perforatedplatewith50%porosityandtheyareusedtosimulateobstacle-inducedturbulence.Sixtestswillbedevotedtoexaminingleanhydrogencombustionunderturbulentconditions;ignitionwillbeinitiatedatthebottomofthevessel.Fouradditionaltestswillbeconductedusing14%and20/hydrogen-airmixtureswhentheignitionsourcewillbeplacedatthecenterofthetestvessel.Thetimeneededtocompletethesetestsisexpectedtobeaboutonemonth.PartIVofthehydrogencombustionprogramentailsatotalofsix7tests.Priortoperformingthesetests,aweek'stimeisneededtosetupthevestrigwhichincludesasphereusedintheprevioustests.Ignitionforthesetestswillbeinitiatedateitherthecenterofthesphereorattheendofthepipef'rhydrogenmixturesofeither8%or20%.Inadditiontocollectingthetemperatureandpressuredata,ionizationprobeswillbeusedtorecordflamepropagationfromonecompartmentto,another.Thefinaltwotestsusingthistestgeometryincludestudyinghydrogencombustioncharacteristicsfroma8%ora10%mixturetoa6%mixture.IntheseteststhepipewillbeIfilledwitha8/or'10%mixture,whilethesphereisfilledwitha6/mixture.Ignitionwillbeinitiatedinthepipesection.Thedurationofthesetestsisanticipatedtobeaboutthreeweeks.

-Thesecondexperimentalprogramthatwillbecarriedthroughatthellhiteshellfacilityinvolvesresearchanddevelopmenteffortonvariousignitertypes.Theobjectiveofthisworkistoperformextensivebenchmarktestsinasixcubicfootsphericaltestvesseltoidentifyignitertypesandtodemonstratetheircombustioncapabilityinaprototypicenvironment.ThetestingprogramwillbegininMayandlastaboutfourmonths.Basedontestdataobtained,a'selectionofigniterswillthenbefurthertestedinalargerscaletestvessel(600ft)atAcurex.Presently,besidestheGMAC7G3glowplugs,afewresistance-heatingglowplugsdevelopedbyTaycowillalsobeexamined.,b)AcurexIntheAcurexprogram,thetestplancanalsobedividedintotwoparts;thefirstpartisdesignedtoexaminetheeffectivenessandtheperformanceof.glowplugsinignitinghydrogenundervariousprototypiccontain-&mentconditions.Intheseexperiments,hydrogenflowrate,steamflowrate,waterspraysparametersandignitorlocationswill'evariedtoprovideparametricstudiesontheabilityofglowplugs'oignitehydrogenmixtures.Theeffectofmicro-fogonglowplugignitionandpressuretransientswillalsobeinvestigated.Anumberoftheexperimentswillattempttoprovidedatatocorrelatefoggingasapressuresuppressantwithsprayvolume,spraydropsize,andhydrogenconcentrations.Astrongignitionsource,e.g.,electricmatch,willbeusedinallthefogging-relatedtests.AsecondpartofthetestplancallsfortestingaselectednumberofignitersdevelopedattheWhiteshellNuclearResearchEstablishment.Thesewillbelargescaleconfirmatorytestsforignitiondeviceswhichhavedemonstratedasuperiorpotentialinignitingleanhydrogenmixturesandin\ replacingtheexistingglowplugdesignsinthefuture.Theireffectiveness~~~~~~~~~~~inasprayenvironmentwillbeevaluatedatAcurex's600ftvessel.Priortocarryingthroughtheabovedescribedtest'plan,aseriesofshakedowntestswillbeperformedtoprovidechecksforconsistencyandaccuracyofallinstrumentation;specifically,resultswillbecomparedwiththoseobtainedatMhiteshellandfromtheavailableliterature.c)HanfordEnineerinDevelomentLaboratorHEDLTheobjectiveofthiseffortistoexperimentallyinvestigateaspectsofhydrogenmixinganddistributioninasimulatedicecondenserlowercompartmentgeometry.Hydrogenreleaseintothecompartmentwillbemodelledbytwoapproaches.Inthefirstapproach,steamandhydrogenareintroducedasajetintothecompartmentsimulatingapipebreak;inthesecondapproach,hydrogenandsteamareaddedtothecompartmentasadiffusesourcesimilartopressurizerrelieftankrelease.Inordertoextendtherangofhydrogenconcentrationbeyond"4%%d,heliumwillbeusedasasimulationfluidinplaceofhydrogen.Confirmatorytestswillbeperformedtodemonstratethatheliumcanindeedbeusedtosubstitutehydrogeninthesemixirigstudies.ThefirsttestisscheduledtobeginsometimeinmidJuneandthewholetestprogramisexpectedtolastapproximatelytwomonths.Inthemeantime,similitudeandscalingcalculationsarebeingdonesoastoproperlymodelthenecessaryparametersthatarevitaltotheinvestigationofmixinganddistribution.Someofthenon-dimensionalgroupsthatarebeingexaminedare:theRichardsonnumber,theReynoldsnumber,andtheGrashofnumber.d)FactorMutualResearchAEP,Duke,TVAandEPRIrecentlycametotheconclusionthatinordertobetterunderstandfoggingasameansofhydrogencontrolandtoeventually 0 renderadecisiononitsapplicabilityasaviablesolutiontohydrogenmitigation,theywouldcontractwithFactoryMutualResearchtoundertakearesearchprogramtoinvestigatefogging.Theobjectiveofthisprogramistodeterminetheeffectsofmicro-foguponthelowerflammabilitylimit(LFL)ofhydrogen,toprovidearelationshipbetweendropsizeandfoggingdensityonLFLandtocorrelatetheconcentrationsofleanhydrogenairmixtureswithvariousfoggingparameters.InordertoensurethattheeffectsoffoggingonLFLareproperlyreproduced,astrongignitionsourcehasbeenproposedandislikelytobeusedtoinitiateignitiononallLFLtests.Therangeofdropletsizesthatisofinteresttotheutilitiesvariesfromafewmicronstohundredsofmicrons,whereasthefoggingdensityvariesfromzerotoa.fewpercent.Test~~~~~~~parametersthatwillbemeasuredincludetemperature,pressure,dropsizedistribution.andfog.densitydistribution.Aschematicof.theexperimentalsetupisshowninFigure5-1.AdetailtestplanisbeingpreparedbyFactoryMutualResearchwithaidfromAEPandtheotherparticipants.Thetestvesselisscheduledtobecomeavailablefortestinapproximatelythreeweeks.Finally,itisalsotheintentofthisefforttoprovidethenecessaryandpertinentinformation'oassistintheselectionoftestparametersintheAcurexfoggingtests.e)CLASIXIntheAEP-NRCmeetingonMarch18,1981,thestaffexpressedinterestinreviewinga-numberofadditionalCLASIXruns.ThefirstconcerncentersaroundtheuniquelowercontainmentspraycapabilityatCookanditspossibleeffectuponothercompartmentresponsesduringandsubsequenttoahydrogenburn. 0 ReviewsatAEPindicatethatintheCLASIXsensitivitystudysubmittedtotheNRC,sprayparameterssuchassprayflowrate,dropletsize,heattransfercharacteristi'cstothedropandspraytemperaturewerevaried;minimaleffectsonthecontainmentpressureandtemperatureresponseswerenoted.Thus,theavailableinformationfromCLASIX,pointsoutthatvariationsinsprayparameterswouldnotsignificantlyaffectcontainmenttemperatureandpressureresponse.AnotherpossibleCLASIXrundiscussedintheabovementionedmeetinginvolvedinitiatinghydrogencombustionat10%with50%burnfraction.Experimentalmeasurementsoncompletenessofhy'drogencombustionreportedintheliteratureshowthatinspiteofthelargescatteringindataaround5%to7%,aninitial10/concentrationconsistentlyresultsinanalmost100%(1)burn.Inaddition,ithasbeenshownthatturbulencewillfurtherenhancecompletenessofcombustionforleanhydrogenmixtures.Therefore,iftheprobabilityofincompletecombustionof10%isindeednegligiblysmall,asitseemstobe,itseffectsuponthecontainmentneednotbeinvestigated.Itwassuggestedbythestaffthatacasewithignitioninitiatedat10%andthenpropagatingtoa8%hydrogenconcentrationregionshouldbestudied.Bothtypesofcombustionwouldassumea100%burnfraction.CloseexaminationofthevariouscasespresentedintheCLASIXsensitivitystudiesrevealsthatthereisonecase(JVD15)whichusestheexactinputparametersrequestedbythestaff.Oneburnwasobservedintheuppercompartmentwithanestimatedmaximumpressureof57psia(onlyoneairrecirculationfanwasassumedtobeoperationalintherun).ThismaximumpressureisveryclosetotheCookcontainmentelasticlimit.However,sinceheatsinkshavenotbeenincludedinthesesensitivitycalculations,theresultsarelikely.tobeoverly~~conservative. Floivmeter-AirpressureMixer-Flowmeter-RegulatorWaterFlashArrostorAir-SolonoldOporatedValveSolonold/OporatodValveFogNozzles/IX/I/I/H>-AirMixSupplyLineSparkGap~EloctrodeslonizatlonProbosForFlamoSpoodlAoasuromonts6"Dlcmeter~x~LongthIihr'(Iii/il/IIIiIII4-Thermocoeploe,bRopSfhE:hl~sug~NQ7)peal~DrainFIGURE5-1EXPERIMENTALARRANGEl1ENTOFFOGGINGTESTS

References:

(1)LiuD.D.S.,etal,"SomeResultsofWNREExperimentson,HydrogenCombustion,"WaterReactorSafetyWorkshopontheImpactofHydrogen,Albuquerque,NewMexico,January1981.(2)Hertzbert,M.,"FlammabilityLimits'ndPressureDevelopmentinH2-AirMixtures,"U.S.BureauofMines,PRCReportNo.4305,January1981. DONALDC.COOKNUCLEARPLANTUNITNOS.1AND2ATTACNENTNO.5TOAEP:NRC:00500ASECONDQUARTERLYREPORTONHYDROGENMITIGATIONANDCONTROL t~ 5.0CurrentResearchProramsSeveralresearchprogramshavebeenundertakenbyAEPtoinvestigatehydrogencontrolrelatedphenomena;someoftheseprogramsweredi.scussedinthelastquarterlyreport.Inthissectionanumberofthecurrentresearchprogramswillbereviewed;programstatus,revisedtestplanandprogramscheduleofeacheffortwillbediscussedindividually.1.1~EAEP,alongwithDukeandTVA,areco-sponsorsoffourEPRIresearchprogramsinwhichfundamentalflamestudieswillbemade;researchanddevelopmentonvariousignitertypeswillbepursued;mixinganddistributionofhydrogeninprototypiccontainmentenvironmentswillbeinvestigatedandadditionalglowplugtestingwillbeperformed.a)WhiteshellNuclearResearchEstablishmentThisresearchfacilityisoperatedbyAtomicEnergyofCanadaLimited.1Tworesearchprogramswillbepursuedindependentlyatthisfacility;namely,the'hydrogencombustionphenomenastudyandtheresearchanddevelopmentofdifferentignitertypes.BothoftheseprogramswillbeundertakenwiththecollaborationofOntarioHydroasanadditionalfinancialcontributortothework.Thefirstexperimentalprogramisdesignedtoinvestigatevarioushydrogencombustionphenomenaandcanbedividedintofourparts.Thefirstpartofthisexperimentaleffortentailsperfororingnineteenignitiontestsonleanhydrogenmixtures.Thehydrogenconcentrationtobeexaminedin'thesetestswillvaryfrom5.0$to305byvolume.Asparkignitionsourcewhichis 0 intheorderof0.5joulewillbeusedtoignitethemixture.Detailsoftheexperimentalsetupandtestvesseldimensionshavebeenpresentedinthepreviousquarterlysubmittal.Fastresponsepressuretransducers,thermo-couplesandionizationprobeswillbeemployedtomonitorandrecordvariousimportanttestparameters.Ofthenineteentestsplannedthemajorityofthemwillbeconductedwiththeignitionsparklocatednearthebottomofthesphericaltestvessel.Twotestsareplannedinwhichtheignitionsourcewillbelocatedatthecenterofthevesselandonetestisplannedwiththeignitionsourcenearthetopofthevessel.Thesethreetestswillbeusedtoassesstheeffectofigniterlocation.Thesetestsareanticipatedtorequireapproximatelythreeweekstocomplete.AccordingtothelatestestimateprovidedbyWNRE,systemshakedownisbeingperformedonthetestvesselandonthedataacquisitionsystem;itisexpectedthatdatacollectionwillbeginbyearlyNay.PartIIofthehydrogencombustionprogramincludesatotalofeighteentestswhichareintendedtostudysphericaldeflagrationsofahydrogenflame.Thehydrogenconcentrationsthatwillbeinvestigatedrangefrom105to421whereasthesteamconcentrationswillvaryfrom0to30Ã.Withtheexceptionoftwotestsinwhichignition.willbeinitiatedatthebottomofthetestvesselalltestswillbeperformedusingcenterignition.Thetime'requiredtocompletethesetestsisapproximatelyonemonth.Subsequenttotheseteststhetestvesselwillbemodifiedforthestudyofturbulenteffectsonhydrogencombustion.Twoweekshavebeenscheduledjntheprogramplantoaccomplishthesemodifications.

TheprimaryobjectiveofthePartIIItestsistoinvestigateturbulenteffectsuponcompletenessofhydrogenburns,anduponpressureandtemperatureresponses.Turbulenceinthesetestswillbecreatedbytwodifferentmeans:1)two16"diametervariablespeedfansand,2)gratings.Thefansareratedat1500cfmeachandconsequentlyarecapableofcreatingaveryturbulentenvironment.Thegratingsaremadeof1/4"perforatedplatewith50/porosityandtheyareusedtosimulateobstacle-inducedturbulence.Sixtestswillbedevotedtoexaminingleanhydrogencombustionunderturbulentconditions;ignitionwillbeinitiatedatthebottomofthevessel.Fouradditionaltestswillbeconductedusing14/and20/hydrogen-airmixtureswhentheignitionsourcewillbeplacedatthecenterofthetestvessel.Thetimeneededtocompletethesetestsisexpectedtobeaboutonemonth.PartIVofthehydrogencombustionprogramentailsatotalofsixtests.Priortoperformingthesetests,aweek'stimeisneededtosetupthetestrigwhichincludesasphereusedintheprevioustests.Ignitionforthesetestswillbeinitiatedateitherthecenterofthesphereorattheendofthepipeforhydrogenmixturesofeither8/or205.Inadditiontocollectingthetemperatureandpressuredata,ionizationprobeswillbeusedtorecordflamepropagationfromonecompartmenttoanother.Thefinaltwotestsusingthistestgeometryincludestudyinghydrogencombustioncharacteristicsfroma8Ãora10Ãmixturetoa6Xmixture.Intheseteststhepipewillbefilledwitha8Ãor105mixture,whilethesphereisfilledwitha6Xmixture.Ignitionwillbeinitiatedinthepipesection.Thedurationofthesetestsisanticipatedtobeaboutthreeweeks' ~~ Thesecondexperimentalprogramthatwi11becarried.throughattheWhiteshellfacilityinvolvesresearchanddevelopmenteffortonvariousignitertypes.The.objectiveofthisworkistoperformextensivebenchmarktestsinasixcubicfootsphericaltestvesseltoidentifyignitertypesandtodemonstratetheircombustioncapabilityinaprototypicenvironment.ThetestingprogramwillbegininMayandlastaboutfourmonths.Basedontestdataobtained,aselectionofigniterswillthenbefurthertestedinalargerscaletestvessel(600ft)atAcurex.Presently,besidestheGMAC7G3glowplugs,afewresistance-heatingglowplugsdevelopedbyTaycowillalsobeexamined.b)AcurexIntheAcurexprogram,thetestplancanalsobedividedintotwoparts;thefirstpartisdesignedtoexaminetheeffectivenessandtheperformanceofglowplugsinignitinghydrogenundervariousprototypiccontain-mentconditions.Intheseexperiments,hydrogenflowrate,steamflowrate,waterspraysparametersandignitorlocationswillbevariedtoprovideparametricstudiesontheabilityofglowplugstoignitehydr'ogenmixtures.Theeffectofmicro-fogonglowplugignitionandpressuretransientswi11alsobeinvestigated.Anumber,oftheexperimentswillattempttoprovidedatatocorrelatefoggingasapressuresuppressantwi.thsprayvolume,spraydropsize,andhydrogenconcentrations.Astrongignitionsource,e.g.,electricmatch,willbeusedinallthefogging-relatedtests.AsecondpartofthetestplancallsfortestingaselectednumberofignitersdevelopedattheWhitqshellNuclearResearchEstablishment.Thesewillbelargescaleconfirmatorytestsforignitiondeviceswhichhavedemonstrateda'uperiorpotentialinignitingleanhydrogenmixturesandin h replacingtheexistingglowplugdesignsinthefuture.Theireffectivenessinasprayenvironmentwillbe.evaluatedatAcurex's600ftvessel.Priortocarryingthroughthe'abovedescribedtestplan,aseriesofshakedowntestswillbeperformedtoprovidechecksforconsistencyandaccuracyofallinstrumentation;specifically,resultswillbecomparedwiththoseobtainedatWhiteshellandfromtheavailableliterature.c)HanfordEnineerinDevelomentLaboratorHEDLTheobjectiveofthiseffortistoexperimentallyinvestigateaspectsofhydrogenmixinganddistributioninasimulatedicecondenserlowercompartmentgeometry.Hydrogenreleaseintothecompartmentwillbemodelledbytwoapproaches.Inthefirstapproach,steamandhydrogenareintroducedasajetintothecompartmentsimulatingapipebreak;inthesecondapproach,hydrogenandsteamareaddedtothecompartmentasadiffusesourcesimilartopressurizerrelieftankrelease.Inordertoextendtherangeofhydrogenconcentrationbeyond45,heliumwillbeusedasasimulationfluidinplaceofhydrogen.Confirmatorytestswillbeperformedtodemonstratethatheliumcanindeedbeusedtosubstitutehydrogeninthesemixingstudies.ThefirsttestisscheduledtobeginsometimeinmidJuneandthewholetestprogramisexpectedtolastapproximatelytwomonths.Inthemeantime,similitudeandscalingcalculationsarebeingdonesoastoproperlymodelthenecessaryparametersthatarevitaltotheinvestigationofmixinganddistribution.Someofthenon-dimensionalgroupsthatarebeingexaminedare:theRichardsonnumber,theReynoldsnumber,andtheGrashofnumber.d)FactorMutualResearchAEP,Duke,TVAandEPRIrecentlycametotheconclusionthatinordertobetterunderstandfoggingasameansofhydrogencontrolandtoeventually

renderadecisiononitsapplicabilityasaviablesolution,tohydrogenmitigation,theywouldcontractwithFactoryMutualResearchtoundertakearesearchprogramtoinvestigatefogging.Theobjectiveofthisprogramistodeterminetheeffectsofmicro-foguponthelowerflammabilitylimit(LFL)ofhydrogen,toprovidearelationshipbetweendropsizeandfoggingdensityonLFLandtocorrelatetheconcentrationsofleanhydrogenairmixtureswithvariousfoggingparameters.InordertoensurethattheeffectsoffoggingonLFLareproperlyreproduced,astrongignitionsourcehasbeenproposedandislikelytobeusedtoinitiateignitiononallLFLtests.Therangeofdropletsizesthatisofinteresttotheutilitiesvariesfromafewmicronstohundredsofmicrons,whereasthefoggingdensityvariesfromzerotoafewpercent.Testparametersthatwillbemeasuredincludetemperature,pressure,dropsizedistributionandfogdensitydistribution.Asch'ematicoftheexperimentalsetupisshowninFigure5-1.AdetailtestplanisbeingpreparedbyFactoryMutualResearchwithaidfromAEPandtheotherparticipants.Thetestvesselisscheduledtobecomeavailablefortestinapproximatelythreeweeks.Finally,itisalsotheintentofthisefforttoprovidethenecessaryandpertinentinformationtoassistinthese1ectionoftestparametersintheAcurexfoggingtests.e)CLASIXIntheAEP-HRCmeetingonMarch18,1981,thestaffexpressedinterestinreviewinga.numberofadditionalCLASIXruns.Thefirst.concerncentersaroundtheuniquelowercontainmentspraycapabilityatCookanditspossibleffectuponothercompartmentresponsesduringandsubsequenttoahydrogenburn. ReviewsatAEPindicatethatintheCLASIXsensitivitystudysubmittedtotheNRC,sprayparameterssuchassprayflowrate,dropletsize,heattransfercharacteristicstothedropandspraytemperaturewerevaried;minimaleffectson,thecontainmentpressureandtemperatureresponseswerenoted.Thus,theavailableinformationfromCLASIX,pointsoutthatvariationsinsprayparameterswouldnotsignificantlyaffectcontainmenttemperatureandpressureresponse.AnotherpossibleCLASIXrundiscussedintheabovementionedmeetingin'volvedinitiatinghydrogencombustionat10/with50%burnfraction.ExperimentalmeasurementsoncompletenessofhydrogencombustionreportedintheliteratureshowthatinspiteofthelargescatteringindataaroundI5Xto7X,aninitial10Ãconcentrationconsistentlyresultsinanalmost100'5(1)burn.Inaddition,ithasbeenshownthatturbulencewillfurtherenhancecompletenessofcombustionforleanhydrogenmixtures.Therefore,iftheprobabilityofincompletecombustionof105isindeednegligiblysmall,asitseemstobe,itseffectsuponthecontainmentneednotbeinvestigated.Itwassuggestedbythestaffthatacasewithignitioninitiatedat10/andthenpropagatingtoa8/hydrogenconcentrationregionshouldbestudied.Bothtypesofcombustionwouldassumea100/burnfraction.CloseexaminationofthevariouscasespresentedintheCLASIXsensitivitystudiesrevealsthatthereisonecase(JVD15)whichusestheexactinputparametersrequestedbythestaff.Oneburnwasobservedintheuppercompartmentwithanestimatedmaximumpressureof57psia(onlyoneairrecirculationfanwasassumedtobeoperationalintherun).ThismaximumpressureisveryclosetotheCookcontainmentelasticlimit.However,sinceheatsinkshavenotbeenincludedinthesesensitivitycalculations,theresultsarelikelytobeoverlyconservative. ll~y!t Floemeter-AlrPror."ouroMixerFlowmetor-RegulatorV/atorFlashArrostorAir-SolenoidOperatedValve/SolenoidOporatodValveFogNozzles/gii/IIH-AirMixSupplyLine2SparkGap~EioctrodoslonizatlonProbesForFlamoSpoodMoasuromantsO"nromolor~x~Lnnnth/iiia/(Iii/'lIIIIIIihermocouplos,bROPS!~MEAsuklNQPEVlcCDrainFIGURE5-1EXPERIMENTALARRANGEMENTOFFOGGINGTESTS

References:

(1)LiuD.D.S.,etal,"SomeResultsofWNREExperimentson-HydrogenCombustion,"WaterReactorSafetyWorkshopontheImpactofHydrogen,Albuquerque,NewMexico,January1.981.(2)Hertzbert,M.,"FlammabilityLimitsandPressureDevelopmentinH2-AirMixtures,"U.S.BureauofMines,PRCReportNo.4305,.January1981. DONALDC.COOKNUCLEARPLANTUNITNOS.1AND2ATTACHMENTNO.6TOAEP:NRC:00500ASECONDQUARTERLYREPORTONHYDROGENMITIGATIONANDCONTROL I 6.0CoreCoolinCaabilitSubseuenttoHdroenCombustion6.1'ntroductionThewrite-upbelowaddressestheexistingcomponentsnecessarytoachieveandmaintainasafeshutdownconditionsubsequenttoareactortripandtomaintainasafeshutdownconditionandcontain-mentintegrityviaadequatehydrogencontrolduringandafterahypotheticaldegradedcorecoolingevent.I6.2SafeShutdownThethreeprimaryfunctionstobeperformedinordertoachieveandmaintainasafeshutdownconditionsubsequenttoareactortripare:(1)circulationofreactorcoolant(2)residualheatremoval(3)controlofRCSpressure'hemethods6ywhich.each.o$thesefunctionscanbe'erformed,.-,andthenecessaryequipmentlocatedinsidecontainment,arediscussedbelow.6.2.1-CirculationofReactorCoolantCirculationofreactorcoolantisprovidedbynatural*circulationwiththereactorcoreservingastheheatsourceandthesteamgeneratorsservingastheheatsink.Waterisprovidedtothesteamgeneratorsviathesafety-gradeAuxiliaryFeedwaterSystem(AFS)or,ifoffsitepowerisavailableandsufficientsteamisavailable,viathenormalfeedwatersystem..TheAFScanbealignedtotakesuctionfromtheEssentialServiceWaterSyst'm,whichitself,takessuctionfromLakei Michigan,thusassuringavirtuallylimitlesssupplyofcoolingwaterforthesteamgenerators.Steamreleasepathsincludeturbinebypass(ifoffsitepowerisavailable)usingthemaincondenser,themainsteamsafetyvalves,andthemainsteampoweroperatedreliefvalves.Thoseportionsofthereactorcoolantsystem,mainfeed-watersystem,auxiliaryfeedwatersystem,andmainsteamsysteminsidecontainmentcontainnoactivecomponentsrequiredtooperatetoassurecoolantcirculationandoperationofsaidsystemswo'ul'.dnotbe.adversel'y-affected'y;"ahydrogencombustionenvironment.Theequipmentlocatedinsidecontainmentneededto.assureadequatereactorcoolantcirculationislistedbelow.ThesusceptibilityofthisequipmenttoahydrogencombustionenvironmentandtheeffectsofsuchanenvironmentonequipmentoperationareaddressedinAttachmentNos.3and4ofthissubmittal,respectively.l.SteamGeneratorNarrow-RangeLevelMonitors2.PressurizerWaterLevelMonitors3.PressurizerPressureMonitors4.LoopRTDs5.CoreExitThermocouples6.RCSWideRangePressureMonitors 1 6.2.2ResidualHeatRemovalResidualheatisremovedviathesteamgeneratorsutilizingthemethodsandequipmentdescribedin6.2.1above.Forthesamereasonssetforthin6.2.1,thisfunctionisnotadverselyaffectedbyahydrogencombustionenvironment.6.2.3RCSPressureControlSubsequenttoareactortrip,RCSpressureismaintainedutilizingthe'.naturalcirculation'quipmentdescribedabove,withthepressurizer(PZR)safetyvalvesservingashighpressureprotection.ThePZRsafetyvalvesareselfcontained,springloadedvalvesandwouldnotbeadverselyaffectedbyahydrogencombustionenvironment.AsecondaspectofRCSpressuremaintenancedealswithisolationofthevariousbranchlinesattached.totheRCS.Eachofthesepotentialleakagepaths,includingthemethodofisolation,isdiscussedbelow.(1)PressurizerPower0cratedReliefValvesPORVsEachPORVisnormallyclosedandi.sdesignedtofailcloseduponlossofairorlossofpower.Inaddition,ablockvalveislocatedupstreamofeachPORVtoassureRCSisolationintheeventthatPORVleakageweretodevelop. (2)LetdownLineLetdownisolationisprovidedbythreeparallelfail-closedairoperatedvalveslocatedinsidecontain-mentandafail-'closedairoperatedvalveoutsidecontainment.Thesevalveswillautomaticallycloseonasafetyinjectionsignal.(3)ExcessLetdown/SealMaterIn'ectionFlowfromtheexcessletdownheatexchangerisdirected.tothereactorcoolantpumpsealwaterreturnline(connectioninsidecontainment)whichisisolatedbytwomotoroperatedvalvesinseries,oneinsidereactorcontainmentandoneoutsidecontainment.Thesevalveswillautomaticallycloseonasafetyinjectionsignal.(4)ResidualHeatRemovalRHRLetdown'heRHRletdownlineisisolatedbytwonormallyclosedmotoroperatedvalvesinserieslocatedinsidereactorcontainment.BothvalvesareinterlockedwithRCSwide-rangepressuretoautomaticallycloseonincreasingpressureabove600psigandcannotbeopeneduntilRCSpressurehasdecreasedbelow426psig.Inaddition,thevalvecontrolswitchesareadministrativelykeylockedclosed'inthemaincontrolroomduringpoweroperation. (5)ReactorVesselHeadVentThereactorvesselheadventsystemconsistsoftwo-.redundantparallelpaths,eachpathcontainingtwonormallyclosed,solenoidactuatedvalvesinseriesforisolation.Thesevalvesaredesignedtofailcloseduponlossofpower.6.3HdroenControlEuimentOperationofthecontainmentairrecirculation/hydrogen.:skimmer(CAR/HYS)fansandtheDISinconjunctionwiththecontainmentspraysystem(CTS)furtherassuresthecombustionof'leanhydrogenmixtureswithoutposingathreattothecontainmentstructureviaoverpressurization.TheportionoftheCTSinsidecontainment.xontainsnoactivecomponentsandhenceCTSoperationisnotadversely:affectedbyahydrogencombustionenvironment.TheactivecomponentsinsidecontainmentusedforhydrogencontrolaretheCAR/HYSfans-,andtheDIS.Theelectricalhydrogenrecombinerswouldbeusedto'removeresidualhydrogen(lessthan4volumepercent)fromthe.containmentsubsequenttoDISoperation.:6.4ECCSInjectionSubseuenttoCombustion:AnevaluationhasbeenmadetoverifyECCSinjectioncapabilitysubsequenttohydrogencombustioninsidecontainment.Theresultso'fthisevaluationindicatedthathigh-headsafetyinjection(SI)(chargingpumps)flowpathviatheBITandtheintermediate/lowhead'SI(SIandRHRpumps)flowpathtotheRCScoldlegswillbeunaffected byhydrogencombustion.Theseflowpathscontainmotoroperatedvalvesinsidecontainment.ThesevalvesreceiveasignaltoopenonaSIsignaldespitethefacttheyarenormallyintheopenposition,thusprovidingfurtherassuranceofECCSinjectioncapability.Nomechanismhasbeenidentifiedwherebytheenvironmentassociatedwithhydrogencombustionwouldresultinclosureofthesevalves.Withtherefuelingwaterstoragetank(RWST)available,twelveweightpercentboricacidcanbedeliveredtotheRCSbyaligningthesuctionofthechargingpumpstotheRWSTandaligningthepump(s)dischargetotheboroninjectiontank(BIT).Asecondflowpathinvolvesalignmentofthechargingpumpsuctiontothedischargeoftheboricacidtransferpumps,whicharethemselvesalignedtotakesuctionfromtheboricacidtankswiththedischargeofthechargingpumpsagainalignedtotheBIT.Neitheroftheabovedescribedflowpathsutilizecomponents(eg.valves)insidecontainmentwhicharerequiredtochangeposition/functioninahydrogenburnenvironment.IntheeventthatthecontentsoftheRWSThadalreadybeeninjectedcoolantinjectionisachievedbyaligningthechargingpump(s)suctiontothedischargeoftheresidualheatremoval(RHR)pump(s);withtheRHRpump(s)takingsuctionfromthecontainmentrecirculationsump.Thisthirdflowpathdoesnotutilizeanyactivecomponentsinsidecontainmentwhicharesusceptibletoahydrogencombustionenvironment.

Thesubjectvalvesarefullyqualifiedforpost-accident.useinsidecontainment(LOCA/MSLBqualification).Inaddition,;theanalysesdescribedinAttachmentNo.4tothisreportclearlyshowthattheenvironmentalconditionsassociatedwithhydrogen.combustionarelessseverethantheenvironmentto.whichtheyhave:beenqualified;thusassuringmaintenanceoftheaforementioned.flowpaths.Thenormallyclosedmotoroperatedvalvesinthe-intermediate/lowheadSIflowpathhavealsobeenqualifiedforuse-inaLOCA/NSLBenvironmentandwouldbeexpectedtoremaininoperation:subsequenttohydrogencombustion;thusprovidinganotherECCSinjectionpath.

DONALDC.COOKNUCLEARPLANTUNITNOS.1AND2ATTACHMENTNO.7TOAEP:NRC:00500ASECONDQUARTERLYREPORTONHYDROGENMITIGATIONANDCONTROL 7.0PreliminarSafetEvaluation~~~Indiana5MichiganElectricCo.(IQ1ECo.)hasdecidedtoinstallaDistributedIgnitionSystem(DIS)intheDonaldC.CookNuclearPlantUnitNos.1and2.TheDISinconjunctionwithoperationofexistingsafety-relatedequipmentprovidesadditionalhydrogencontrolcapabilityintheextremelyunlikelyeventofadegradedcoreeventsimilarinnaturetotheTMI-2accidentinvolvingthegenerationofsubstantiveamountsofhydrogen.TheDIS,describedindetailinAttachmentNo.2ofthisreport,isdesignedtoassurecombustionofleanhydrogen/air/steammixturesandhencewillminimizethepressureandtemperaturetransientsassociatedwithhydrogencombustion.Conservativeanalysesofthecontainmentresponsehavepreviouslybeensubmittedviaourfirstquarterlyreport(AEP:NRC:00500).TheresultsoftheseanalysesindicatethatdeliberateignitionofleanhydrogenmixturesusingtheDISwillresultinpressuresbelowtheultimatestrengthoftheCookPlantcontainments.TheeffectsofahydrogencombustionenvironmentonnecessaryequipmentlocatedinsidecontainmenthasbeenevaluatedandtheresultsofthisevaluationpresentedinAttachmentNo.4ofthisreport.ItisclearfromourevaluationthatthetemperatureeffectsoFdeliberatehydrogencombustionarelessseverethanthosetowhichmostofthenecessaryequipmenthasbeenqualified(LOCA/MSLBqualification).Ithasalsobeenshownthattheabilitytoinjectemergencycorecoolingwaterisnotaffectedbyhydrogencombustion. TheextensiveplantmodificationsandenhancedoperatortrainingimplementedsubsequentlytotheTNI-2accidenthaveeffectivelyreducedthealreadylowprobabilityofoccurrenceofeventswhichcouldresultinthegenerationofsubstantiveamountsofhydrogenattheCookPlant'.TheDIS,inconjunctionwithexistingplantequipment>willprovideanadditionallevelofmitigationcapabilityforhypotheticaleventswellbeyondthedesignbasisoftheCookUnits,furtherenhancingthedefense-in-depth.philosophy.InstallationoftheDISprovidesfurtherassurancethatoperationoftheCookPlantwillinnowayadverselyeffectthehealthandsafetyofthegeneralpublic. ah4}}

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