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{{#Wiki_filter:DONALDC.COOKNUCLEARPLANTUNITNOS.1AND2.ENCLOSURETOAEP:NRC:00500FIRSTQUARTERLYREPORTONHYDROGENISSUESgyp~~tkSO=3/5(',nn,(ging/g/IPOSI'g0"Ipt".~V-ofBscUmon5R'aiJU~ORYINMETFfLE 1.INTRODUCTIONInourresponsetoMr.D.G.Eisenhut'sletterofSeptember22,1980,submittalno.AEP:NRC:00476,datedOctober7,1980,AmericanElectricPowerServiceCorporation(AEP)describedtheeffortsunderwaytoinvestigatetheneedforadditionalhydrogencontrolcapabilityinIndiana8MichiganElectricCompany'sDonaldC.CookNuclearPlant.OurletteralsostatedthatAEP,inconjunctionwiththeTennesseeValleyAuthority(TVA)andDukePowerCompany(Duke)wasinvolvedinaresearchanddevelopmentprogramtoinvestigateadditionalhydrogencontrolmeasuresforpostulatedaccidentswellbeyondtheCookPlantdesignbasis.Thissubmittalisthefirstquarterlyreportandprovides.thestatusoftheseeffortsandplannedanalyticalandexperimentalprograms.ThoseprogramsbeingjointlyperformedundertheauspicesoftheAEP/TVA/DukeTaskForcearedescribedinSection2below.EffortsuniquetoAEPandtheDonaldC.CookNuclearPlantaredescribedinSections4and5below.2.AEP/TVA/DUKEPROGRAMSINPROGRESS2.1FenwalI'nitorTests-AseriesoftestswereperformedattheFenwalInc.LaboratoriestodeterminetheignitioncharacteristicsofaGeneralMotorsAC(Model7G)'glowplug'ypeignitor.Theignitorwastestedinvariousmixturesofhydrogen,steam,andairandinthepresenceofwatersprayandfanflow.Representative'safety-related'quipment(bothwithandwithoutinsulation)wasplacedinthetestvesselanditstemperatureresponsetohydrogencombustionmonitored.Theresultsofthistesting,whichhavebeenpreviouslysubmittedtotheCoranissionbyTVA,indicatethattheModel7Gglowplugisareliableignitionsourceforhydrogenconcentrationsbetween6and12volumepercent.Thetemperatureandpressuretransientsduetohydrogencombustionandthehydrogenburnfractionsobservedduringthetestswereconsistentwithpreviouslypubl'ishedinformation.Thebenefitofinsulatingtemperaturesensitiveequipmentwithathinsheetofaluminumfoilwasclearlyshownbythetests.2.2HALONFeasibilitStudTheAtlanticResearchCorporation(ARC)hasbeencontractedtoperformafeasibilitystudyfortheuseofaHALONInjectionSystemtosuppresshydrogencombustioninicecondensercontainments.TheARCstudyisexpectedtobecompletedbyFebruary1,1981.ApreliminaryreportbyARC(Attachment1)indicatesthatHALONdissolationmaybeasignificantconcerninapost-LOCAenvironment.ItshouldbenotedthatthepHofapproximately2.2indicatedinAttachment1doesnotaccountforthesodiumhydroxideadditiveintheCookPlantContainmentSpraysolutionwhichwould,ofcourse,resultinalessacidicsolution.
{{#Wiki_filter:DONALDC.COOKNUCLEARPLANTUNITNOS.1AND2.ENCLOSURE TOAEP:NRC:00500 FIRSTQUARTERLY REPORTONHYDROGENISSUESgyp~~tkSO=3/5(',nn,(ging/g/IPOSI'g0"Ipt".~V-ofBscUmon5 R'aiJU~ORY INMETFfLE 1.INTRODUCTION InourresponsetoMr.D.G.Eisenhut's letterofSeptember 22,1980,submittal no.AEP:NRC:00476, datedOctober7,1980,AmericanElectricPowerServiceCorporation (AEP)described theeffortsunderwaytoinvestigate theneedforadditional hydrogencontrolcapability inIndiana8MichiganElectricCompany's DonaldC.CookNuclearPlant.OurletteralsostatedthatAEP,inconjunction withtheTennessee ValleyAuthority (TVA)andDukePowerCompany(Duke)wasinvolvedinaresearchanddevelopment programtoinvestigate additional hydrogencontrolmeasuresforpostulated accidents wellbeyondtheCookPlantdesignbasis.Thissubmittal isthefirstquarterly reportandprovides.thestatusoftheseeffortsandplannedanalytical andexperimental programs.
2.3ElectromaneticInterferenceStudDr.B.E.Keiserhasbeencontractedtoassesstheelectromagneticinterference(EMI)emissionsfromasparkdischargeignitor.Dr.Keiser'sstudyisexpectedtobe.completedbyAprilI,1981.2.4CatalticCombustorStudTheAEP/TVA/DukeTaskForceisreviewingaproposalbyAcurexCorporationtotestacatalyticcombustorforpossibleuseinapost-accidentenvironment.Thisdevicewouldbetestedunderaseriesofconditionsofvaryinghydrogenandsteamconcentrationsbothwithandwithout'hepresenceofpoisons.Ifpractical,acatalyticcombustorwouldbeplacedonthedischargeofeachofthecontainmentairrecirculationfanstoeffectivelycontrolhdyrogenconcentrationwithoutintroducingthe.potentialforwidespreadcombustionthroughoutthecontainmentasisthecasewithaDistributedIgnitionSystem.2.5CLASIXImrovementsTheAEP/TVA/DukeTaskForcehasgivenapprovaltoWestinghouse(W)OffshorePowerSystems(OPS)toimplementanumberofchangestoCLASIX.Inordertorealisticallyassessthecontainmentresponseofanicecondenserplanttohydrogencombustiontheexistingadiabaticburnmodels,whichleadtoexcessiveconservatisminthepredictedresults,shouldbemodified.ThedurationofeachburnhasbeenestimatedbyCLASIXtobeintheorderofseconds;thisimpliesthatheattransferbetweenthecombustionregionanditssurroundingmightnotbenegligible.AcontainmentstructureheatsinkmodelwillbeformulatedandaddedtoCLASIXtoaccountfortheheatdissipatedtothecontainmentenvironment;heattransportbymeansofconvectionandradiationwillbeexplicitlymodeled.Anylatentheatreleasedfromthecondensationprocesswillalsobeincludedintheenergybalancecalculationofthecontainment.Usingthemulti-layerconductionmodel,theaforementionedheattransfercorrelationswillbeincorporatedinCLASIXtomodelstructuralheatsinks.IntheexistingCLASIXcalculations,airrecirculationfanflowcharacteristicsandfancoolerperformancearenotmodeled.Theincor-porationoftheairrecirculationfan/headflowcurveintoCLASIXwillprovidebetter,flowdescriptionsbetweencompartments;asaresult,inter-compartmentflowratescanbecharacterizedbycompartmentdifferentialpressure.TheoptionofusingthefancoolerswhicharedesignedtoremoveheatfromthecontainmentduringnormalplantoperationwillalsobeaddedtoCLASIX.Theseimprovementsareattemptstoprovideamoreaccuratedescriptionofthetemperatureandpressureresponseofthecontainmentintheunlikelyeventofhydrogencombustion.SaidimprovementsarescheduledtobecompletedbyJanuary1981. 3.AEP/TVA/DUKEPROGRAMSPLANNEDInajointeffortwithEPRI,theAEP/TVA/DukeTaskForcehasunderconsiderationaresearchprogram,toinvestigatevariousaspectsofhydrogen-relatedissues;includingignitortests,parametricstudiesofhydrogencombustionlimits,andinvestigationofprinciplesofhydrogenmixingandturbulenceeffects.Fourdifferenteffortsarescheduledtostartinthefirstquarterof1981.ThedeterminationofthescopeandtestparametersforthesestudiesistobedecideduponbetweenEPRIandtheAEP/TVA/DukeTaskForceinJanuary1981.Thecurrentproposalsfortheseprogramsandtheirschedulesaresummarizedbelow:3.1RockwellInternationalIgnitordevelopmenttestswillbeperformedbythecontractorinwhichdifferentignitortypesanddesignswillbetested.Thetestfacilityincludesacylindricalvessel,5footdiameterby6feetlongwithapressureratingof150psi.Sparkplug,hotsurfaceandcombustionwaveignitorswillbeusedtoigniteleanmixturesofhydrogenandairundersteamorwatersprayenvironments.Itistheintentofthisefforttoestablishcombustioncharacteristicsofvariousignitorsandtoevaluatetheireffectiveness.AlltestingiscurrentlyscheduledforcompletionbyJune1981.3.2AECLllhiteshellExperimentswillbeconductedineitheran8-footdiametersphereora5-footdiameterby19-foothighcylinder.l.Athydrogenconcentrationslessthan10Ã,experimentswillbeconductedtodeterminewhethersizeandshapeofthevesselaffectstheextentofreaction.ResultswillbecomparedwithdatacollectedatWhiteshellina2-litercylindricalvessel.2.AthydrogenconcentrationsgreaterthanlOX,thelaminarburningvelocityasafunctionofhydrogenconcentrationsandtemperatureswillbeverified.Ignitionofuniformhydrogen/air/steammixtureswillbeinvestigatedasafunctionofpressure,temperatureandburnvelocities.3.Turbulenceeffectsinacontainmentwhichmaybecausedbythermalconvectioncurrentsorbyobstacles,suchaspipes,grids,etc.willbestudied.4.Flamepropagationfromonecompartmenttoanotheratvarioushydrogenconcentrationscanalsobeinvestigated.
Thoseprogramsbeingjointlyperformed undertheauspicesoftheAEP/TVA/Duke TaskForcearedescribed inSection2below.EffortsuniquetoAEPandtheDonaldC.CookNuclearPlantaredescribed inSections4and5below.2.AEP/TVA/DUKE PROGRAMSINPROGRESS2.1FenwalI'nitorTests-Aseriesoftestswereperformed attheFenwalInc.Laboratories todetermine theignitioncharacteristics ofaGeneralMotorsAC(Model7G)'glowplug'ypeignitor.Theignitorwastestedinvariousmixturesofhydrogen, steam,andairandinthepresenceofwatersprayandfanflow.Representative
4-ThefirstmeetingtodiscusstheplanwiththetestingcontractorisscheduledforearlyFebruary.ExperimentsareexpectedtobeginbyApril1,1981andfinishbyAugust1981.3.3AcurexCororationThecontractorwillperformstudiesonmitigationphenomenasuchastheeffectsofwaterspray,fogandHalononignitionandcombustionofhydrogenandairmixtures.Acylindricalvessel,78"ID,400cubicfeetwillbeusedin.thetest.Controlledamountsofhydrogen,air,steamandwaterspraycanbeintroducedinthetestvesseltosimulatevariouspostulatedconditions.Differenttypesofigniterscanalsobeinstalledinthetestsectiontobetested.Uniformhydrogenconcentrationwithinthetestvesselisensuredbytheoperationofacirculationfan.Provisionscanbemadeavailabletoobtainphotographicrecordsofthecombustionprocess.ContractnegotiationisscheduledtobegininJanuaryof1981andthefirsttestisexpectedtostartinApril.TheexperimentalprogramisduetobecompletebyJuly1981.3.4HEDLTestswillbeconductedattheHEDLContainmentSystemTestFacility.Thesetestswillnotinvolveignitionofthetestvolume.Theprimarypurposeofthisstudyistoinvestigatehydrogenmjxing,stratificationanddistributioninalargeopenvolume(30,000ft~).Parameterswhichaffectthedistributionandmixingofhydrogenwillbeexamined.Theyinclude:thermalgradients,effectsofsprays,steam,naturalandforcedconvectioneffects.Compartmentscanalsobeformedwithinthelargevolumetostudyhydrogendistributionundervariousconditions.Detailsoftheexperimentalprogramwillbediscussedinaforth-comingmeetingplannedforJanuarywithinvestigatorsfromHEDL.ThetestprogramisexpectedtobeginonMarch1,1981andconcludebyJune1981.'.REPORTONAEPSPECIFICWORK4.1CLASIXAnalsesforCookPlantTheCookPlanticecondensercontainmentresponsetohypotheticalhydrogenburntransientshasbeenanalyzedutilizingtheWestinghouse/OffshorePowerSystems'OPS)CLASIXcomputercode.TheresultsoftheCookPlantanalysesarecontainedintheattachedOPSreportentitled"SummaryofAnalysesofD.C.CookContainmentResponsetoHydrogenTransients"(Attachment2).
'safety-related'quipment (bothwithandwithoutinsulation) wasplacedinthetestvesselanditstemperature responsetohydrogencombustion monitored.
Theresultsofthistesting,whichhavebeenpreviously submitted totheCoranission byTVA,indicatethattheModel7Gglowplugisareliableignitionsourceforhydrogenconcentrations between6and12volumepercent.Thetemperature andpressuretransients duetohydrogencombustion andthehydrogenburnfractions observedduringthetestswereconsistent withpreviously publ'ished information.
Thebenefitofinsulating temperature sensitive equipment withathinsheetofaluminumfoilwasclearlyshownbythetests.2.2HALONFeasibilit StudTheAtlanticResearchCorporation (ARC)hasbeencontracted toperformafeasibility studyfortheuseofaHALONInjection Systemtosuppresshydrogencombustion inicecondenser containments.
TheARCstudyisexpectedtobecompleted byFebruary1,1981.Apreliminary reportbyARC(Attachment 1)indicates thatHALONdissolation maybeasignificant concerninapost-LOCA environment.
ItshouldbenotedthatthepHofapproximately 2.2indicated inAttachment 1doesnotaccountforthesodiumhydroxide additiveintheCookPlantContainment Spraysolutionwhichwould,ofcourse,resultinalessacidicsolution.
2.3Electroma neticInterference StudDr.B.E.Keiserhasbeencontracted toassesstheelectromagnetic interference (EMI)emissions fromasparkdischarge ignitor.Dr.Keiser'sstudyisexpectedtobe.completed byAprilI,1981.2.4CatalticCombustor StudTheAEP/TVA/Duke TaskForceisreviewing aproposalbyAcurexCorporation totestacatalytic combustor forpossibleuseinapost-accidentenvironment.
Thisdevicewouldbetestedunderaseriesofconditions ofvaryinghydrogenandsteamconcentrations bothwithandwithout'he presenceofpoisons.Ifpractical, acatalytic combustor wouldbeplacedonthedischarge ofeachofthecontainment airrecirculation fanstoeffectively controlhdyrogenconcentration withoutintroducing the.potential forwidespreadcombustion throughout thecontainment asisthecasewithaDistributed IgnitionSystem.2.5CLASIXImrovements TheAEP/TVA/Duke TaskForcehasgivenapprovaltoWestinghouse (W)OffshorePowerSystems(OPS)toimplement anumberofchangestoCLASIX.Inordertorealistically assessthecontainment responseofanicecondenser planttohydrogencombustion theexistingadiabatic burnmodels,whichleadtoexcessive conservatism inthepredicted results,shouldbemodified.
Thedurationofeachburnhasbeenestimated byCLASIXtobeintheorderofseconds;thisimpliesthatheattransferbetweenthecombustion regionanditssurrounding mightnotbenegligible.
Acontainment structure heatsinkmodelwillbeformulated andaddedtoCLASIXtoaccountfortheheatdissipated tothecontainment environment; heattransport bymeansofconvection andradiation willbeexplicitly modeled.Anylatentheatreleasedfromthecondensation processwillalsobeincludedintheenergybalancecalculation ofthecontainment.
Usingthemulti-layer conduction model,theaforementioned heattransfercorrelations willbeincorporated inCLASIXtomodelstructural heatsinks.IntheexistingCLASIXcalculations, airrecirculation fanflowcharacteristics andfancoolerperformance arenotmodeled.Theincor-porationoftheairrecirculation fan/headflowcurveintoCLASIXwillprovidebetter,flowdescriptions betweencompartments; asaresult,inter-compartment flowratescanbecharacterized bycompartment differential pressure.
Theoptionofusingthefancoolerswhicharedesignedtoremoveheatfromthecontainment duringnormalplantoperation willalsobeaddedtoCLASIX.Theseimprovements areattemptstoprovideamoreaccuratedescription ofthetemperature andpressureresponseofthecontainment intheunlikelyeventofhydrogencombustion.
Saidimprovements arescheduled tobecompleted byJanuary1981. 3.AEP/TVA/DUKE PROGRAMSPLANNEDInajointeffortwithEPRI,theAEP/TVA/Duke TaskForcehasunderconsideration aresearchprogram,to investigate variousaspectsofhydrogen-related issues;including ignitortests,parametric studiesofhydrogencombustion limits,andinvestigation ofprinciples ofhydrogenmixingandturbulence effects.Fourdifferent effortsarescheduled tostartinthefirstquarterof1981.Thedetermination ofthescopeandtestparameters forthesestudiesistobedecideduponbetweenEPRIandtheAEP/TVA/Duke TaskForceinJanuary1981.Thecurrentproposals fortheseprogramsandtheirschedules aresummarized below:3.1RockwellInternational Ignitordevelopment testswillbeperformed bythecontractor inwhichdifferent ignitortypesanddesignswillbetested.Thetestfacilityincludesacylindrical vessel,5footdiameterby6feetlongwithapressureratingof150psi.Sparkplug,hotsurfaceandcombustion waveignitorswillbeusedtoigniteleanmixturesofhydrogenandairundersteamorwatersprayenvironments.
Itistheintentofthisefforttoestablish combustion characteristics ofvariousignitorsandtoevaluatetheireffectiveness.
Alltestingiscurrently scheduled forcompletion byJune1981.3.2AECLllhiteshell Experiments willbeconducted ineitheran8-footdiametersphereora5-footdiameterby19-foothighcylinder.
l.Athydrogenconcentrations lessthan10Ã,experiments willbeconducted todetermine whethersizeandshapeofthevesselaffectstheextentofreaction.
Resultswillbecomparedwithdatacollected atWhiteshell ina2-litercylindrical vessel.2.Athydrogenconcentrations greaterthanlOX,thelaminarburningvelocityasafunctionofhydrogenconcentrations andtemperatures willbeverified.
Ignitionofuniformhydrogen/
air/steam mixtureswillbeinvestigated asafunctionofpressure, temperature andburnvelocities.
3.Turbulence effectsinacontainment whichmaybecausedbythermalconvection currentsorbyobstacles, suchaspipes,grids,etc.willbestudied.4.Flamepropagation fromonecompartment toanotheratvarioushydrogenconcentrations canalsobeinvestigated.
4-Thefirstmeetingtodiscusstheplanwiththetestingcontractor isscheduled forearlyFebruary.
Experiments areexpectedtobeginbyApril1,1981andfinishbyAugust1981.3.3AcurexCororationThecontractor willperformstudiesonmitigation phenomena suchastheeffectsofwaterspray,fogandHalononignitionandcombustion ofhydrogenandairmixtures.
Acylindrical vessel,78"ID,400cubicfeetwillbeusedin.thetest.Controlled amountsofhydrogen, air,steamandwaterspraycanbeintroduced inthetestvesseltosimulatevariouspostulated conditions.
Different typesofigniterscanalsobeinstalled inthetestsectiontobetested.Uniformhydrogenconcentration withinthetestvesselisensuredbytheoperation ofacirculation fan.Provisions canbemadeavailable toobtainphotographic recordsofthecombustion process.Contractnegotiation isscheduled tobegininJanuaryof1981andthefirsttestisexpectedtostartinApril.Theexperimental programisduetobecompletebyJuly1981.3.4HEDLTestswillbeconducted attheHEDLContainment SystemTestFacility.
Thesetestswillnotinvolveignitionofthetestvolume.Theprimarypurposeofthisstudyistoinvestigate hydrogenmjxing,stratification anddistribution inalargeopenvolume(30,000ft~).Parameters whichaffectthedistribution andmixingofhydrogenwillbeexamined.
Theyinclude:thermalgradients, effectsofsprays,steam,naturalandforcedconvection effects.Compartments canalsobeformedwithinthelargevolumetostudyhydrogendistribution undervariousconditions.
Detailsoftheexperimental programwillbediscussed inaforth-comingmeetingplannedforJanuarywithinvestigators fromHEDL.ThetestprogramisexpectedtobeginonMarch1,1981andconcludebyJune1981.'.REPORTONAEPSPECIFICWORK4.1CLASIXAnalsesforCookPlantTheCookPlanticecondenser containment responsetohypothetical hydrogenburntransients hasbeenanalyzedutilizing theWestinghouse/
OffshorePowerSystems'OPS)
CLASIXcomputercode.TheresultsoftheCookPlantanalysesarecontained intheattachedOPSreportentitled"SummaryofAnalysesofD.C.CookContainment ResponsetoHydrogenTransients" (Attachment 2).
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Theinitial(pre-hydrogengeneration)containmentconditionsinputtoCLASIXwereobtainedfromtheWestinghouseLOTICcomputercode.ThehydrogengenerationratefortheS2DsequencewasobtainedfromtheMARCHcomputercodeaswerethetimedependentmassandenergyreleaseratesfromthepostulatedbreak.TheassumptionsutilizedintheCLASIXanlaysesareconsistentwiththoseusedintheTVAandDukestudies.ParametersspecifictotheCookPlant,suchasfanflowratesandflowlosscoefficientsbetweencompartments,aresummarizedinTableNos.3and4oftheOPSreport.UnliketheTVAandDukeCLASIXstudies,theCookPlantcalculationalmodelincludedaseparatenodalvolumerepresentativeofthetwofan/accumulatorroomsandaccountedforthepresenceofcontainmentspraycapabilityinboththelowercompartmentandthefan/accumulatorrooms.ThesignificanceofthesedifferencesisdiscussedinSection4.2below.EFourcaseswereexaminedbyCLASIXinwhichthecriteriaforignitionandflamepropagationwerevaried.AsummaryoftheresultsofthesecasesiscontainedinTable5oftheOPSreport.Thefirstcase,JVAC1,doesnotaccountforcontainmentsprayflowinthelowercompartmentandfanaccumulatorrooms.Thiscase,whichisnottypicaloftheCookcontainment,wasanalyzedtoobtainbaselineinformationsufficientto"allowcomparisonwiththeTVAandDukestudies.Theremainingthreecasesaccountforspray,flowinthelowercompartmentandthefan/accumulatorroomsaswellastheuppercompartmentandarereflectiveoftheCooksystems.4.2EvaluationofCLASIXResultsReviewoftheOPSreportindicatesthatthepresenceoflowercompartmentsprayshasa.significantbeneficialeffectonthecontainmentresponsetohydrogencombustion.Themostnotableeffectsarethereductionofthepeaktemperatureinthelowercompartmentbyafactorofapproximatelytwo(relativetotheJVAC1case)andthetemperaturereductionbetweenburns.Itisalsoapparentthatthisadditionalspraycapabilityeffectivelyreducestheamountoficemeltedasaresultofahydrogenburn(s).Reviewofthetimedependenttemperaturetransientsinthefan/accumulatorroomsandthedead-endedvolumeforcasesJVAC2,JVAC3,andJVAC4suggeststhathydrogenignitioninside,orflamepropagationinto,theseareasishighlyunlikely.Inonlyoneinstance(JVAC3)doesthepeaktemperatureineitherofthoseareasexceed270oF.TheJVAC3casepredictstwotemperaturespikesinthefan/accumulatorrooms.Thesespikes,showninFigure26ofthe  OPSreport,appeartobeofveryshortduration.Therelativenon-susceptibilityoftheseareastotheadverseenvironmentassociatedwithhydrogenburningisaveryimportantfactortobeconsideredwhenevaluatingequipmentsurvivability.Itwaspreciselyforthatreason;todeterminetheenvironmentalconditionsintheseareasduringhydrogentransients,thattheCookPlantcalculationalmodelwasmodifiedtoincludeaseparatefan/accumulatorroomnodalvolume.AnindependentevaluationoftheCLASIXresultsisbeingperformedbyAEP.TheintentofthiseffortistoprovideareviewoftheassumptionsandtheanalyticalmethodusedinCLASIX.Veryimportantinformationoncontainmentresponseresultingfromhydrogencombustionhasbeenprovidedbythecomputercode;however,inordertofullyutilizethedata,verificationwillberequired.Forinstance,CLASIXresultsindicatethatthereareaseriesofburnsoccurringwhenever;.thereiscombustioninsideacompartment,themultiplicityofcombustionandthedurationtimeofeachburnwouldhavetobeevaluatedtoensurethattheyreflecttheactualphenomenonandnotthenumericaloranalyticalschemethatischoseninthecode.Propagationtoadjacentchambersispresentlyartificiallyimposedinthecodeandthusconditionsforflamepropagationarenotexplicitlymodeled.TheAEPreviewwillattempttoidentifysomeofthelimitationsofthecodewherebyCLASIXresultscanbemoreaccuratelyinterpretedandapplied.4.3CLASIXResultsYs.ContainmentUltimateStrenthPreliminarycalculationofthecontainmentultimatestrengthshowsthatunderthestaticloadassumption,thelimitofthecontainmentshellis69.7psiaandtheequipmenthatchisestimatedtobe40.8psia.Itisprudenttorecallthattheselimitswerecomputedbasedoncertainconservativeassumptions;forinstance,theselectionofmaterialstrength.CLASIXresultstabulatedinTable5,Attachment2,withcompletecombustion,predictedthat10v/ohydrogenmixturethecontainmentwillexperienceapeakpressureof27.5psiawhereasan85hydrogencombustionwillyieldapeakpressureof25.0psia.AccordingtoCLASIX,bothofthesemaximawilloccurintheicecondenserwiththeuppercompartmentexperiencingapressurepeakofasimilarmagnitude.Abouta10Kreductioninmaximumpressureinthelowercompartmentisreported.ThehighestpressurecalculatedbyCLASIXis33.5psiaoccurringintheuppercompartmentundera10$combustionwithflamepropagationcriteriontoadjacentcompartmentat8v/o.A31.0psiapeakispredictedinsidetheicecondenserand26.5psiapeakinthelowercompartment.
Theinitial(pre-hydrogen generation) containment conditions inputtoCLASIXwereobtainedfromtheWestinghouse LOTICcomputercode.Thehydrogengeneration ratefortheS2DsequencewasobtainedfromtheMARCHcomputercodeaswerethetimedependent massandenergyreleaseratesfromthepostulated break.Theassumptions utilizedintheCLASIXanlaysesareconsistent withthoseusedintheTVAandDukestudies.Parameters specifictotheCookPlant,suchasfanflowratesandflowlosscoefficients betweencompartments, aresummarized inTableNos.3and4oftheOPSreport.UnliketheTVAandDukeCLASIXstudies,theCookPlantcalculational modelincludedaseparatenodalvolumerepresentative ofthetwofan/accumulator roomsandaccounted forthepresenceofcontainment spraycapability inboththelowercompartment andthefan/accumulator rooms.Thesignificance ofthesedifferences isdiscussed inSection4.2below.EFourcaseswereexaminedbyCLASIXinwhichthecriteriaforignitionandflamepropagation werevaried.Asummaryoftheresultsofthesecasesiscontained inTable5oftheOPSreport.Thefirstcase,JVAC1,doesnotaccountforcontainment sprayflowinthelowercompartment andfanaccumulator rooms.Thiscase,whichisnottypicaloftheCookcontainment, wasanalyzedtoobtainbaselineinformation sufficient to"allowcomparison withtheTVAandDukestudies.Theremaining threecasesaccountforspray,flowinthelowercompartment andthefan/accumulator roomsaswellastheuppercompartment andarereflective oftheCooksystems.4.2Evaluation ofCLASIXResultsReviewoftheOPSreportindicates thatthepresenceoflowercompartment sprayshasa.significant beneficial effectonthecontainment responsetohydrogencombustion.
BasedonCLASIXandultimatecontainmentstrengthcalculations,themaximumpeakcontainmentpressurepredictedinvariousselectedhydrogencombustionscenariosisconsistentlybelowtheultimatestaticpressurecapacityofthecontainmentascalculatedbyStructuralMechanicsAssociates.Furtherstudiesarebeingconductedtoassesswithimprovedcertaintytherelationshipbetweenhydrogencombustioncontainmentresponseanditsultimatestrengthcapability.5.COOKCONTAINMENTULTIMATECAPABILITY5.1OverviewofCookContainmentStructuralDesinBeforediscussingtheAEPcommentsontheNRCconsultant'sreportontheultimatepressurecapabilityoftheCookcontainmentandAEP'sowncalculation,abriefsummaryisgiveninthisSectionofthestructuredesignfeaturesrelatedtoultimatecontainmentstrength.TheDonaldC.CookNuclearPlantcontainmentbuildingisasteellinedreinforcedconcretecylindricalstructurewithahemisphericaldomeandaflatbasemat.Thenormalconcretestrengthis3500psiat28days.Thereinforcedconcretebasemathasanaveragethicknessof10'-0".Thetopofthefoundationmatislinedwith4"thicksteelplateandtheplateiscoveredwithatwofootthickreinforcedconcreteslab.Thecylinderhasadiameterof115'-0"insidetoinsideofthe3/8"thickliner.Thereinforcedconcretewallsare4'-6"thickatthebasemattaperingto3'-6"atsevenfeetabovethebaseandcontinuingat3'-6"tothespringlinewhichis113feetabovethebasemat.Thereinforcedconcretedomehasaninsideradiusequivalenttothatofthecylinder.Theconcretethicknessofthedomevariesgraduallyfrom3'-6"atthespringlineto2'-6"atthepeak.Thebasematismadeintwolayerswhicharetiedtogetherbymeansof811reinforcingbarsspacedat6'-0"oncenter.Thereinforcinginthecylinderwallsisgenerallytworowsof818at12"oncentercircumferentiallyandfourrowsof818at9"oncenterto14'-0"abovethebase;fourlayersof818at9"oncenterbetween14'-0"and21'-0"abovethebase,twolayersof818at18"oncenterbetween12'-0"andthespringline.Additionally,therearefourlayersofdiagonallyoriented818at36"oncenterreinforcing.Thereisalsoshearreinforcinginzonesbetweenthebaseslabelevationandapproximately15'bovethebaseandagain,35'o56'bovethebaseslab.Shearreinforcingisagainprovidedatthespringline.
Themostnotableeffectsarethereduction ofthepeaktemperature inthelowercompartment byafactorofapproximately two(relative totheJVAC1case)andthetemperature reduction betweenburns.Itisalsoapparentthatthisadditional spraycapability effectively reducestheamountoficemeltedasaresultofahydrogenburn(s).Reviewofthetimedependent temperature transients inthefan/accumulator roomsandthedead-ended volumeforcasesJVAC2,JVAC3,andJVAC4suggeststhathydrogenignitioninside,orflamepropagation into,theseareasishighlyunlikely.
LLThedomehoopreinforcingconsistsoftwolayersof818at12"oncenterto35abovethespringline,andthentwolayersof818at18"oncenterfrom35otothepeak.Meridionalreinforcingconsistsoftwolayersof//18at18"plusonelayerof811at18"to50abovethespringline.Therearetwolayersof818at18"from50tothepeak.Additionally,therearefourlayersofdiagonallyoriented818at36"oncenterplacedto20oabovethespringlineandshearreinforcingto10'bovethespringline.There-barisASTM-615Grade40.The'linerisASTMA442Grade60.Thepersonnelhatchisa10'-0"diagonalbarrelanchoredintothecontainmentcylinderwall.Theequipmenthatchisa20'-0"diagonalbarrelanchoredintothecontainmentcylinderwallandhavinga10'-0"diagonalpensonnelairlockinsert.Theequipmenthatchbarrelandthepersonnelhatchbarrelareeachanchoredtothecontainmentbymeansoftwo3/4"thickcollars.ThematerialsofthepersonnelandequipmenthatchesareASTHA516Grade70andASTHA193'radeB7forthebolting.ThematerialoftheanchoredbarrelisASTMA300fireboxA516Grade70.5.2CommentsonDr.Harstead'sReortItem1ofAttachment3tothisreportcontainscommentsbyDr.J.D.StevensonofStructuralMechanicsAssociates(SMA}onDr.Harstead'sreport.5.3AEPSecificCalculationResultsItem2ofAttachment3containsasummaryofAEPcontainmentanalysespresentlyunderway.5.4Dr.Stevenson'sPresentationatDecember181980MeetinItem3ofAttachment3containsasummary,includingslides,ofthepresentationgivenbyDr.StevensonattheAEP-NRCmeetingheldinBethesda,MarylandonDecember18,1980.6.DISTRIBUTEDIGNITIONSYSTEMDESIGNSTUDYAsstatedinourAEP:NRC:00476submittal,AEPisproceedingwithadesignstudyforinstallationofaDistributedIgnitionSystem(DIS}intheCookPlantcontainments.Toasgreatanextentaspossible,theCookDISdesignparallelstheSequoyahandMcGuiredesigns.Itisourintentiontoinstallthein-containmentportionoftheDISduringthe1981refuelingoutages,ifrequiy;ed. TheDISconsistsofsixty-eightigniterassemblieslocatedindistinctareasofthecontainmentbuilding.Twoigniterassemblies,onefromeachofTrains'A'nd'B',shallbelocatedineachofthirty-fourdesignatedareas.Eachigniterassemblyconsistsofathermalresistanceheatingelement(glowplug),GeneralMotorsACPlugType7G,andaDonganElectricControlPowerTrnasformer(Model52-20-435).Theglowplugandtransformeraremountedinasealedboxwhichemploysheatshieldstominimizethetemperatureriseinsidetheboxanda'dripshield'oreducedirectwaterimpingementonthethermalelement.6.1DISDesinCriteriaTheintentof.aDISistoreliablyinitiatecombustionofrelativelyleanhydrogenmixtures.The.'followingcriteriawereusedintheselectionoftherecommendedigniterlocationscontainedabove.1.Allproposedigniterlocationsareinareaswellmixedbythehydrogenskimmer/airrecirculationfansystems.2.Ingeneral,ignitersshouldbemountedneaitheceilingwithinagivenvo'lume.3.AlligniterswiththeexceptionofthoseinthevicinityofthePRTaretobelocatedabovemaximumflood-uplevel.4All.DIS.cables..installedmnside.containment.mustbeyJatectedLfrom.orqualifiedtowithstandtheenvironmentassociatedwithasmallLOCAandhydrogencombustion.5.AllDIScablesoutsidecontainmentmustbeprotectedfromorqualifiedtowithstandtheenvironmentassociatedwithaworstcasehighenergylinebreak.6.Trains'A'nd'B'ftheDISaretobeelectricallyisolatedfromeachother.7.DIScomponentsaretobesupportedtoSeismicCategoryIstandards.6.2IniterLocationsThepreliminaryDISfortheCookPlanthasignitersinthefollowinglocations;equallydistributedbetweenTrains'A'nd'B':  AreaLowerVolumeNo.ofIniters12AroximateLocationUniformlyspacedaroundthebiologicalshieldwall.LowerVolumeFanRooms(2)InthevicinityofthePRTrupturedisk.Fourigniters(ineachF/Aroom)equallyseparatedwithinthevol.ume.SG8PREnclosures10Twoignitersinsideeachofthefiveenclosures.UpperVolumeUpperVolume1210Locatedintheupperdomearea;uniformlyspaced.TwoigniterslocatedontheoutsideoftheSG&PZRenclosures.IceCondenser14Twoigniterseachintheupperplenumareaof6ayNos.3,6,9,12,15,18,and21;mountedonthecontainmentwall. 7.ELECTRICHYDROGENRECOMBINERSWestinghouse,attherequestofAEP,hasinvestigatedthepotentialforincreasingelectrichydrogenrecombiner(EHR)capacitytotheextentnecessarytomitigatedegradedcore/hydrogenevents.Westinghousehasdeterminedthataninordinatenumberof(theequivalentofseveralhundred)EHRswouldberequiredtoprovidesufficienthydrogenrecombina-tioncapacitysoastomitigateaneventinwhichthehydrogenfrom75w/ozirconiumoxidationisreleasedtothecontainment(linearly)overaneighthourtimeperiod.ItisimportanttorealizethattheabovecalculationdoesnotaccountinanywayfortheignitioncapabilitiesofthepresentlyinstalledEHR;whichare,ineffect,large-sizedglowplugs.ItwouldbereasonabletoexpecttheEHRstoactasignitionsourcesifandwhenthehydrogenconcentrationexceededthe'recombination'evel.CLASIXanalysesmightbeperformedtoevaluatetheeffectivenessofdeliberateignition,bytheEHRs,onlyintheuppervolume.  
Inonlyoneinstance(JVAC3)doesthepeaktemperature ineitherofthoseareasexceed270oF.TheJVAC3casepredictstwotemperature spikesinthefan/accumulator rooms.Thesespikes,showninFigure26ofthe  OPSreport,appeartobeofveryshortduration.
~)~ATTACHMENT1TOAEP:NRC:00500  
Therelativenon-susceptibility oftheseareastotheadverseenvironment associated withhydrogenburningisaveryimportant factortobeconsidered whenevaluating equipment survivability.
,C,I~IAN'TICRESEARCHCOR90RATION~5390CHEROKEEAVENUE~AIEXANORIAVIRGINIA'2%4~703-642-4000.WX710-832-628November26,1980Dr.WangLauTennesseeValleyAuthority400CommerceAvenueKnoxville,TN37902
Itwasprecisely forthatreason;todetermine theenvironmental conditions intheseareasduringhydrogentransients, thattheCookPlantcalculational modelwasmodifiedtoincludeaseparatefan/accumulator roomnodalvolume.Anindependent evaluation oftheCLASIXresultsisbeingperformed byAEP.Theintentofthiseffortistoprovideareviewoftheassumptions andtheanalytical methodusedinCLASIX.Veryimportant information oncontainment responseresulting fromhydrogencombustion hasbeenprovidedbythecomputercode;however,inordertofullyutilizethedata,verification willberequired.
Forinstance, CLASIXresultsindicatethatthereareaseriesofburnsoccurring whenever;.
thereiscombustion insideacompartment, themultiplicity ofcombustion andthedurationtimeofeachburnwouldhavetobeevaluated toensurethattheyreflecttheactualphenomenon andnotthenumerical oranalytical schemethatischoseninthecode.Propagation toadjacentchambersispresently artificially imposedinthecodeandthusconditions forflamepropagation arenotexplicitly modeled.TheAEPreviewwillattempttoidentifysomeofthelimitations ofthecodewherebyCLASIXresultscanbemoreaccurately interpreted andapplied.4.3CLASIXResultsYs.Containment UltimateStrenthPreliminary calculation ofthecontainment ultimatestrengthshowsthatunderthestaticloadassumption, thelimitofthecontainment shellis69.7psiaandtheequipment hatchisestimated tobe40.8psia.Itisprudenttorecallthattheselimitswerecomputedbasedoncertainconservative assumptions; forinstance, theselection ofmaterialstrength.
CLASIXresultstabulated inTable5,Attachment 2,withcompletecombustion, predicted that10v/ohydrogenmixturethecontainment willexperience apeakpressureof27.5psiawhereasan85hydrogencombustion willyieldapeakpressureof25.0psia.According toCLASIX,bothofthesemaximawilloccurintheicecondenser withtheuppercompartment experiencing apressurepeakofasimilarmagnitude.
Abouta10Kreduction inmaximumpressureinthelowercompartment isreported.
Thehighestpressurecalculated byCLASIXis33.5psiaoccurring intheuppercompartment undera10$combustion withflamepropagation criterion toadjacentcompartment at8v/o.A31.0psiapeakispredicted insidetheicecondenser and26.5psiapeakinthelowercompartment.
BasedonCLASIXandultimatecontainment strengthcalculations, themaximumpeakcontainment pressurepredicted invariousselectedhydrogencombustion scenarios isconsistently belowtheultimatestaticpressurecapacityofthecontainment ascalculated byStructural Mechanics Associates.
Furtherstudiesarebeingconducted toassesswithimprovedcertainty therelationship betweenhydrogencombustion containment responseanditsultimatestrengthcapability.
5.COOKCONTAINMENT ULTIMATECAPABILITY 5.1OverviewofCookContainment Structural DesinBeforediscussing theAEPcommentsontheNRCconsultant's reportontheultimatepressurecapability oftheCookcontainment andAEP'sowncalculation, abriefsummaryisgiveninthisSectionofthestructure designfeaturesrelatedtoultimatecontainment strength.
TheDonaldC.CookNuclearPlantcontainment buildingisasteellinedreinforced concretecylindrical structure withahemispherical domeandaflatbasemat.Thenormalconcretestrengthis3500psiat28days.Thereinforced concretebasemathasanaveragethickness of10'-0".Thetopofthefoundation matislinedwith4"thicksteelplateandtheplateiscoveredwithatwofootthickreinforced concreteslab.Thecylinderhasadiameterof115'-0"insidetoinsideofthe3/8"thickliner.Thereinforced concretewallsare4'-6"thickatthebasemattaperingto3'-6"atsevenfeetabovethebaseandcontinuing at3'-6"tothespringlinewhichis113feetabovethebasemat.Thereinforced concretedomehasaninsideradiusequivalent tothatofthecylinder.
Theconcretethickness ofthedomevariesgradually from3'-6"atthespringlineto2'-6"atthepeak.Thebasematismadeintwolayerswhicharetiedtogetherbymeansof811reinforcing barsspacedat6'-0"oncenter.Thereinforcing inthecylinderwallsisgenerally tworowsof818at12"oncentercircumferentially andfourrowsof818at9"oncenterto14'-0"abovethebase;fourlayersof818at9"oncenterbetween14'-0"and21'-0"abovethebase,twolayersof818at18"oncenterbetween12'-0"andthespringline.Additionally, therearefourlayersofdiagonally oriented818at36"oncenterreinforcing.
Thereisalsoshearreinforcing inzonesbetweenthebaseslabelevation andapproximately 15'bovethebaseandagain,35'o56'bovethebaseslab.Shearreinforcing isagainprovidedatthespringline.
LLThedomehoopreinforcing consistsoftwolayersof818at12"oncenterto35abovethespringline,andthentwolayersof818at18"oncenterfrom35otothepeak.Meridional reinforcing consistsoftwolayersof//18at18"plusonelayerof811at18"to50abovethespringline.Therearetwolayersof818at18"from50tothepeak.Additionally, therearefourlayersofdiagonally oriented818at36"oncenterplacedto20oabovethespringlineandshearreinforcing to10'bovethespringline.There-barisASTM-615Grade40.The'linerisASTMA442Grade60.Thepersonnel hatchisa10'-0"diagonalbarrelanchoredintothecontainment cylinderwall.Theequipment hatchisa20'-0"diagonalbarrelanchoredintothecontainment cylinderwallandhavinga10'-0"diagonalpensonnel airlockinsert.Theequipment hatchbarrelandthepersonnel hatchbarrelareeachanchoredtothecontainment bymeansoftwo3/4"thickcollars.Thematerials ofthepersonnel andequipment hatchesareASTHA516Grade70andASTHA193'rade B7forthebolting.ThematerialoftheanchoredbarrelisASTMA300fireboxA516Grade70.5.2CommentsonDr.Harstead's ReortItem1ofAttachment 3tothisreportcontainscommentsbyDr.J.D.Stevenson ofStructural Mechanics Associates (SMA}onDr.Harstead's report.5.3AEPSecificCalculation ResultsItem2ofAttachment 3containsasummaryofAEPcontainment analysespresently underway.
5.4Dr.Stevenson's Presentation atDecember181980MeetinItem3ofAttachment 3containsasummary,including slides,ofthepresentation givenbyDr.Stevenson attheAEP-NRCmeetingheldinBethesda, MarylandonDecember18,1980.6.DISTRIBUTED IGNITIONSYSTEMDESIGNSTUDYAsstatedinourAEP:NRC:00476 submittal, AEPisproceeding withadesignstudyforinstallation ofaDistributed IgnitionSystem(DIS}intheCookPlantcontainments.
Toasgreatanextentaspossible, theCookDISdesignparallels theSequoyahandMcGuiredesigns.Itisourintention toinstallthein-containment portionoftheDISduringthe1981refueling outages,ifrequiy;ed. TheDISconsistsofsixty-eight igniterassemblies locatedindistinctareasofthecontainment building.
Twoigniterassemblies, onefromeachofTrains'A'nd'B',shallbelocatedineachofthirty-four designated areas.Eachigniterassemblyconsistsofathermalresistance heatingelement(glowplug),GeneralMotorsACPlugType7G,andaDonganElectricControlPowerTrnasformer (Model52-20-435).
Theglowplugandtransformer aremountedinasealedboxwhichemploysheatshieldstominimizethetemperature riseinsidetheboxanda'dripshield'oreducedirectwaterimpingement onthethermalelement.6.1DISDesinCriteriaTheintentof.aDISistoreliablyinitiatecombustion ofrelatively leanhydrogenmixtures.
The.'following criteriawereusedintheselection oftherecommended igniterlocations contained above.1.Allproposedigniterlocations areinareaswellmixedbythehydrogenskimmer/air recirculation fansystems.2.Ingeneral,ignitersshouldbemountedneaitheceilingwithinagivenvo'lume.3.Alligniterswiththeexception ofthoseinthevicinityofthePRTaretobelocatedabovemaximumflood-uplevel.4All.DIS.cables..installedmnside.
containment.
mustbeyJatectedLfrom
.orqualified towithstand theenvironment associated withasmallLOCAandhydrogencombustion.
5.AllDIScablesoutsidecontainment mustbeprotected fromorqualified towithstand theenvironment associated withaworstcasehighenergylinebreak.6.Trains'A'nd'B'ftheDISaretobeelectrically isolatedfromeachother.7.DIScomponents aretobesupported toSeismicCategoryIstandards.
6.2IniterLocations Thepreliminary DISfortheCookPlanthasignitersinthefollowing locations; equallydistributed betweenTrains'A'nd'B':  AreaLowerVolumeNo.ofIniters12AroximateLocationUniformly spacedaroundthebiological shieldwall.LowerVolumeFanRooms(2)InthevicinityofthePRTrupturedisk.Fourigniters(ineachF/Aroom)equallyseparated withinthevol.ume.SG8PREnclosures 10Twoignitersinsideeachofthefiveenclosures.
UpperVolumeUpperVolume1210Locatedintheupperdomearea;uniformly spaced.TwoigniterslocatedontheoutsideoftheSG&PZRenclosures.
IceCondenser 14Twoigniterseachintheupperplenumareaof6ayNos.3,6,9,12,15,18,and21;mountedonthecontainment wall. 7.ELECTRICHYDROGENRECOMBINERSWestinghouse, attherequestofAEP,hasinvestigated thepotential forincreasing electrichydrogenrecombiner (EHR)capacitytotheextentnecessary tomitigatedegradedcore/hydrogen events.Westinghouse hasdetermined thataninordinate numberof(theequivalent ofseveralhundred)EHRswouldberequiredtoprovidesufficient hydrogenrecombina-tioncapacitysoastomitigateaneventinwhichthehydrogenfrom75w/ozirconium oxidation isreleasedtothecontainment (linearly) overaneighthourtimeperiod.Itisimportant torealizethattheabovecalculation doesnotaccountinanywayfortheignitioncapabilities ofthepresently installed EHR;whichare,ineffect,large-sized glowplugs.Itwouldbereasonable toexpecttheEHRstoactasignitionsourcesifandwhenthehydrogenconcentration exceededthe'recombination'evel.
CLASIXanalysesmightbeperformed toevaluatetheeffectiveness ofdeliberate
: ignition, bytheEHRs,onlyintheuppervolume.  
~)~ATTACHMENT 1TOAEP:NRC:00500  
,C,I~IAN'TICRESEARCHCOR90RATION~
5390CHEROKEEAVENUE~AIEXANORIAVIRGINIA'2%4
~703-642-4000
.WX710-832-628November26,1980Dr.WangLauTennessee ValleyAuthority 400CommerceAvenueKnoxville, TN37902


==Reference:==
==Reference:==
ContractTV-55205A-"SystemFeasibilityAnalysisofUsingHalon1301inanIceCondenserContainment"
 
ContractTV-55205A
-"SystemFeasibility AnalysisofUsingHalon1301inanIceCondenser Containment"


==DearDr.Lau:==
==DearDr.Lau:==
Thissummaryletterreportisbeingsubmittedperthecontractrequirement,toprovideaninterimreportinthecourseofthepxogram.UptothepresenttimeavisitwasmadetotheWattsBarplantbyfivetechnicalpersonsassociatedwiththestudy,numeroustelephonediscussionshavebeenheldwithTVA,AEPSCand'ukePowerpersonnel,andagroupfromDukePowervisitedAtlanticResearchforareviewoftheHalonsystemandouropinionaboutalternativeapproaches.Wehavehadrequeststoaccelerateprogressifpossible,whichwearetryingtoaccommodatebut,asexplained,muchoftheworkfollowsasequentialpathandcertaintaskscannotbecompleteduntilotherpriorworkhasbeenperformed.Inbroadsummary,itcanbereportedthataHalon1301systemiscertaintobeabletoprovidefullsafetyagainstanypossiblehydrogenhazardfollowingaLOCAinanicecondensercontainment.Thematterthatremainsdoesnotconcernsafetyacceptability,butratherconcernsthequestionofhowmuchcorrosionmightcertainmaterialsbesubjectedto,andwilltheprimaryandsecondarysystemsmeetspecificationsandberecoverableafteraLOCAiftheywereexposedtoHalondecom-positionproducts.Briefly,thecorrosionpxoblemisasfollows:Halonitselfisstableandinerttowardmaterials.However,ifneededfollowingaLOCA,Halongascoulddis-solvetoasmallextentintheemergencycoolingwater(itssolubilityis150ppmbyweightinwaterat77'Fand0.5atm).Radiolyticdecompositioncanthenoccur,theresultof.whichcouldbetheformationofbromides(andfluorides)inlowcon-centration(about400ppmBr)inthewater.Therefore,thequestionbeingaddressediswhateffectsuchasolutionwillhaveonreactormaterials,particularlystainlesssteels.Ifunfavorableanswersemergefromthematerialsstudy,thentheoptionsarethefollowing:~PlantoinstallaHalon1301systemtoprovidesafetyduringtheinterimwhileanalternativesystemisbeingdeveloped,usingtherationalethatthelikelihoodofhavingtoemployHalonisextremelysmall.  
Thissummaryletterreportisbeingsubmitted perthecontractrequirement, toprovideaninterimreportinthecourseofthepxogram.UptothepresenttimeavisitwasmadetotheWattsBarplantbyfivetechnical personsassociated withthestudy,numeroustelephone discussions havebeenheldwithTVA,AEPSCand'ukePowerpersonnel, andagroupfromDukePowervisitedAtlanticResearchforareviewoftheHalonsystemandouropinionaboutalternative approaches.
(contractTV-55205AInterimReportPageTwo~Studytheeffectofexposureofstainlesssteelstohydrogen.Sincehydrogenhasanembrittlingeffectonsteels,itmaybethathydrogenaloneisdeleteriousenoughthatthereactorsystemcouldnotbere-coveredanyway,evenifHalonwerenotused.~Investigatemeansofeliminatingorreducingtheeffectofbromides.ThegeneralapproachwouldbetofindadditivesthatdefeattheHalonradiolyticdecompositionmechanisminsolution.Severalcandidateapproacheshavebeenconsidered:DetermineifHalondecomposesinsolutioninthepresenceofhydrogenasrapidlyasinitsabsence.HydrogenmaycompetewithHalonforsolvatedelectrons,thespeciesresponsibleforinitiatingHalondegradation.Addanadditivetothewaterthatwillprecipitatebromideininertform.(Asearchforcandidateadditiveswillbemade.)Addanadditivetothewaterthatwillproducehydroxylradi-calsinsolution.Theseradicalsarethoughttoreactwithbromideionstoreversethedecompositionreaction.Alcoholsmaybegoodcandidates.DeterminewhetherdecompositionofHalonwilloccurtothesameextentoverarangeofpHvalues.GenerallyattempttofindadditivesthatmaybeeffectiveinreversingHalondegradation.Substantialprogresshasbeenmadeonthreetasksoftheprogramandeachoftheseisreviewedbelow.SstemDesinIfnocreditisallowedforsteaminerting,itwillrequire191,600lbmassofHalon1301toinertthetotalcontainment,includingupperandlowercompart-mentsandicecondenserplenums(1.2x106ft3).TheHalonrequirementisderivedfromtheflammabilitydataobtainedinthepreviousARCstudyandtheassumptionof75%zirconiumcladdingreactionreleasing1450lbmassofhydrogen.Assumingnegligiblelossesandspecifyinga20%excess,thetotalHalonrequirementwillbe230,000lb.Neglectinglossesis)ustified.becausethecontainmentleakrateisessentiallyzero,andthelosstocoolingwateris4540lbviaHalondecompo>>sitionand880lbthroughdissolution.Thecontainmentpartialpressureswillbe(70'Fbasis):H2Halon1.000atm=14.70psia0.234atm=3.44psia0.493atm=1.727atm=25.33psia=10.7psig ContractTV-55205AInterimReportPageThreeAstorageandpipingconfigurationhasbeend'esignedwhichisbasedontheguidingprinciplethatthesystemmustfunctionproperlyeveniftwoindependentmalfunctionsoccursimultaneously.TheHalonwouldbestoredinfive316stain-lesssteeltanks,fourofwhichwouldcontaintherequired230,000lbandaniden-ticalfifthback-uptankwouldcontain57,500lb.ThestoragetanksaresizedtocontaintheHalonattemperaturesinexcessof130'Fwheretheliquiddensityis77.6lb/ft~Eachtankwouldhaveanequivalentsphericaldiameterof12feet3withawallthicknessofthreeinches.Thisprovidesaworkingpressureof600psigforthesystem,conformingtoSectionVIIIoftheASMEUnifiedPressureVesselCode.Eachtankwouldhaveanassociatedtankofnitrogengasconnectedtoitwhichwouldmaintainadeliverypressureof600psigiftheHalonhadtobedischarged.ThefiveHalontanksarevalvedindependentlytotwomanifoldsoffour-inch.SSSchedule40pipe.(Themanifoldpipingdiametermayhavetobelargerifatotalrunofmuchmorethan300-400feetisrequired,),Twopenetrationsofthecon-tainmentwillberequiredforthefour-inchpipes.ThepipingwillconformtoANSIB-31.10classification.Insidethecontainment,thepipingbranchestotheupperandlowercompartments,eachaccumulatorcompartmentandtheinstrumentroomtomaximizecoverageofisolatedcompartments.Anarrayofspraynozzlescomesoffeachmanifoldpipeinsidethecontainment.Therequirementisto,deliver230,000lbHalonin1000secondsor1330gpmat130'F.Onearrangementtoaccomplishthisistouse20fullconenozzlesof15/32"orificeoneachmanifold,oneofwhichissufficient.Thisfeatureofthesystemdesignisbeingleftopenatpresent.Theexactnozzlesystemconfigurationwould.havetobedeterminedbyactualinspectionofthecontainmentand'computationoftherequire-ment.ineacharea.Thefinalreportwillpresentthesystemdesigninmuchgreaterdetail.Otheraspectsofthedesignarealsobeingworkedon,includinginstrumentalanalysisre-quirements.HalonDecomositionandBromideIonConcentrationSincethenetdecompositionofHalonceasesatequilibriumBrconcentrationof5.2x103moles/1,thetotalquantityofHalondecomposeddepends(atequili-brium)uponthetotalquantityofwaterinthecontainment(6.46x103lbsHalondecomposedpergallon,ofwater).Forthemaximumamount(702,950gallons,re:TVAletterofOct.31,1980),thequantityofHalondecomposedis4540lb,independentofthefissionproductreleasetothewater.Anadditional880lbwillremaindis-solvedinthewater.TherateofHalondecompositionalsodependsuponthequantityofwaterinthecontainment.Thetime-dependentquantityofHalondecomposedforseveralpotentialvaluesofthecontainmentwaterinventoryhasbeencomputedandwillbegiveninthefinalreport.DecompositionofHalonyieldsBrinsolutionwhichactsasascavengerfortheOHradicalandtendstosuppressfurtherHalondecomposition.EquilibriumisattainedataBr-concentrationof5.2x103moles/literalso.
Wehavehadrequeststoaccelerate progressifpossible, whichwearetryingtoaccommodate but,asexplained, muchoftheworkfollowsasequential pathandcertaintaskscannotbecompleted untilotherpriorworkhasbeenperformed.
ContractTV-55205AInterimReportPageFourWaterChemistrandHBr-ispresumablyformedasHBranddecompositionofHalonalsoproducesHFatconcentrations3timesthatofHBr.HFionization,however,issuppressedbytheH+fromHBrionization,andatequilibriummostoftheHFisundissociated.ThepHchangesdependupontheinitialchemicalcompositionandpHofthewaterinthecontainmentsystem.Althoughthesystemwaterwilllikelybeslightlyalkaline(pH>7)andperhapsbuffered(presenceofsodiumborate,forexample,topreventcritica1ity),calculationsofthepHchangeshavebeenmade,conservativelyassumingpurewater(pHof7.0)inthecontainmentsysteminitially.Assumingcom-pleteionizationofHBrandanionizationconstantof3.53x10"4forHF,there-sultingpHatequilibriumwouldbe"2.2,determinedprincipallybytheHBr,withHFionizationlargelysuppressed.Hydrogen-airmixturescanbeinertedagainstcombustionbyadditionofHalon.1301,andalargebodyofdataontheflammabilitylimitsofsuchmixtureshasbeendevelopedpreviouslyusingsparksandsquibsasignitionsources.Thequestionhasarisenastowhetherashockwavecouldignitemixturesthataresoinerted.'nordertoanswerthisquestion,aliteraturesearchisbeingconductedtodetermineifthematterhaseve'rbeenstudied,andananalysisofthehydrogencombustionchemistryisbeingperformed.Todate,theliteraturesearchhasnotturnedupanydirectinformation.Theanalyticalwork,althoughstillincomplete,isindicatingthatonceinertedagainstsparksorpyrotechnicignition,amixturecannotbeshockinitiated.Thisisthetypeofquestionthatlendsitselftoanalyticalstudywhere-indefiniteconclusionsarepossiblebecausehydrogen-oxygencombustionisthebestunderstoodofallfuelsystems.Inaddition,weareexaminingthequestionofwhatstructuraleffectswouldbeexpectedfromexplosionofuninertedpocketsofH2-airozvariousdimensions.Verytrulyyours,ATLANTICRESEARCHCORPORATIONEdwardT.McHale,ManagerCombustionandPhysicalScienceDepartmentETM/blscc:StephenJ.MilotiAmericanElectricPowerServiceCorp.WilliamH.RasinDukePowerCompany ATTACHMENT2TQAEP:NRC:00500 sj~~}}
Inbroadsummary,itcanbereportedthataHalon1301systemiscertaintobeabletoprovidefullsafetyagainstanypossiblehydrogenhazardfollowing aLOCAinanicecondenser containment.
Thematterthatremainsdoesnotconcernsafetyacceptability, butratherconcernsthequestionofhowmuchcorrosion mightcertainmaterials besubjected to,andwilltheprimaryandsecondary systemsmeetspecifications andberecoverable afteraLOCAiftheywereexposedtoHalondecom-positionproducts.
Briefly,thecorrosion pxoblemisasfollows:Halonitselfisstableandinerttowardmaterials.
However,ifneededfollowing aLOCA,Halongascoulddis-solvetoasmallextentintheemergency coolingwater(itssolubility is150ppmbyweightinwaterat77'Fand0.5atm).Radiolytic decomposition canthenoccur,theresultof.whichcouldbetheformation ofbromides(andfluorides) inlowcon-centration (about400ppmBr)inthewater.Therefore, thequestionbeingaddressed iswhateffectsuchasolutionwillhaveonreactormaterials, particularly stainless steels.Ifunfavorable answersemergefromthematerials study,thentheoptionsarethefollowing:
~PlantoinstallaHalon1301systemtoprovidesafetyduringtheinterimwhileanalternative systemisbeingdeveloped, usingtherationale thatthelikelihood ofhavingtoemployHalonisextremely small.  
(contract TV-55205A InterimReportPageTwo~Studytheeffectofexposureofstainless steelstohydrogen.
Sincehydrogenhasanembrittling effectonsteels,itmaybethathydrogenaloneisdeleterious enoughthatthereactorsystemcouldnotbere-coveredanyway,evenifHalonwerenotused.~Investigate meansofeliminating orreducingtheeffectofbromides.
Thegeneralapproachwouldbetofindadditives thatdefeattheHalonradiolytic decomposition mechanism insolution.
Severalcandidate approaches havebeenconsidered:
Determine ifHalondecomposes insolutioninthepresenceofhydrogenasrapidlyasinitsabsence.HydrogenmaycompetewithHalonforsolvatedelectrons, thespeciesresponsible forinitiating Halondegradation.
Addanadditivetothewaterthatwillprecipitate bromideininertform.(Asearchforcandidate additives willbemade.)Addanadditivetothewaterthatwillproducehydroxylradi-calsinsolution.
Theseradicalsarethoughttoreactwithbromideionstoreversethedecomposition reaction.
Alcoholsmaybegoodcandidates.
Determine whetherdecomposition ofHalonwilloccurtothesameextentoverarangeofpHvalues.Generally attempttofindadditives thatmaybeeffective inreversing Halondegradation.
Substantial progresshasbeenmadeonthreetasksoftheprogramandeachoftheseisreviewedbelow.SstemDesinIfnocreditisallowedforsteaminerting, itwillrequire191,600lbmassofHalon1301toinertthetotalcontainment, including upperandlowercompart-mentsandicecondenser plenums(1.2x106ft3).TheHalonrequirement isderivedfromtheflammability dataobtainedinthepreviousARCstudyandtheassumption of75%zirconium claddingreactionreleasing 1450lbmassofhydrogen.
Assumingnegligible lossesandspecifying a20%excess,thetotalHalonrequirement willbe230,000lb.Neglecting lossesis)ustified
.becausethecontainment leakrateisessentially zero,andthelosstocoolingwateris4540lbviaHalondecompo>>sitionand880lbthroughdissolution.
Thecontainment partialpressures willbe(70'Fbasis):H2Halon1.000atm=14.70psia0.234atm=3.44psia0.493atm=1.727atm=25.33psia=10.7psig ContractTV-55205A InterimReportPageThreeAstorageandpipingconfiguration hasbeend'esigned whichisbasedontheguidingprinciple thatthesystemmustfunctionproperlyeveniftwoindependent malfunctions occursimultaneously.
TheHalonwouldbestoredinfive316stain-lesssteeltanks,fourofwhichwouldcontaintherequired230,000lbandaniden-ticalfifthback-uptankwouldcontain57,500lb.ThestoragetanksaresizedtocontaintheHalonattemperatures inexcessof130'Fwheretheliquiddensityis77.6lb/ft~Eachtankwouldhaveanequivalent spherical diameterof12feet3withawallthickness ofthreeinches.Thisprovidesaworkingpressureof600psigforthesystem,conforming toSectionVIIIoftheASMEUnifiedPressureVesselCode.Eachtankwouldhaveanassociated tankofnitrogengasconnected toitwhichwouldmaintainadeliverypressureof600psigiftheHalonhadtobedischarged.
ThefiveHalontanksarevalvedindependently totwomanifolds offour-inch.
SSSchedule40pipe.(Themanifoldpipingdiametermayhavetobelargerifatotalrunofmuchmorethan300-400feetisrequired,),
Twopenetrations ofthecon-tainmentwillberequiredforthefour-inch pipes.ThepipingwillconformtoANSIB-31.10classification.
Insidethecontainment, thepipingbranchestotheupperandlowercompartments, eachaccumulator compartment andtheinstrument roomtomaximizecoverageofisolatedcompartments.
Anarrayofspraynozzlescomesoffeachmanifoldpipeinsidethecontainment.
Therequirement isto,deliver 230,000lbHalonin1000secondsor1330gpmat130'F.Onearrangement toaccomplish thisistouse20fullconenozzlesof15/32"orificeoneachmanifold, oneofwhichissufficient.
Thisfeatureofthesystemdesignisbeingleftopenatpresent.Theexactnozzlesystemconfiguration would.havetobedetermined byactualinspection ofthecontainment and'computation oftherequire-ment.ineacharea.Thefinalreportwillpresentthesystemdesigninmuchgreaterdetail.Otheraspectsofthedesignarealsobeingworkedon,including instrumental analysisre-quirements.
HalonDecomositionandBromideIonConcentration Sincethenetdecomposition ofHalonceasesatequilibrium Brconcentration of5.2x103moles/1,thetotalquantityofHalondecomposed depends(atequili-brium)uponthetotalquantityofwaterinthecontainment (6.46x103lbsHalondecomposed pergallon,ofwater).Forthemaximumamount(702,950gallons,re:TVAletterofOct.31,1980),thequantityofHalondecomposed is4540lb,independent ofthefissionproductreleasetothewater.Anadditional 880lbwillremaindis-solvedinthewater.TherateofHalondecomposition alsodependsuponthequantityofwaterinthecontainment.
Thetime-dependent quantityofHalondecomposed forseveralpotential valuesofthecontainment waterinventory hasbeencomputedandwillbegiveninthefinalreport.Decomposition ofHalonyieldsBrinsolutionwhichactsasascavenger fortheOHradicalandtendstosuppressfurtherHalondecomposition.
Equilibrium isattainedataBr-concentration of5.2x103moles/liter also.
ContractTV-55205A InterimReportPageFourWaterChemistrandHBr-ispresumably formedasHBranddecomposition ofHalonalsoproducesHFatconcentrations 3timesthatofHBr.HFionization, however,issuppressed bytheH+fromHBrionization, andatequilibrium mostoftheHFisundissociated.
ThepHchangesdependupontheinitialchemicalcomposition andpHofthewaterinthecontainment system.Althoughthesystemwaterwilllikelybeslightlyalkaline(pH>7)andperhapsbuffered(presence ofsodiumborate,forexample,topreventcritica1ity),
calculations ofthepHchangeshavebeenmade,conservatively assumingpurewater(pHof7.0)inthecontainment systeminitially.
Assumingcom-pleteionization ofHBrandanionization constantof3.53x10"4forHF,there-sultingpHatequilibrium wouldbe"2.2,determined principally bytheHBr,withHFionization largelysuppressed.
Hydrogen-air mixturescanbeinertedagainstcombustion byadditionofHalon.1301,andalargebodyofdataontheflammability limitsofsuchmixtureshasbeendeveloped previously usingsparksandsquibsasignitionsources.Thequestionhasarisenastowhetherashockwavecouldignitemixturesthataresoinerted.'nordertoanswerthisquestion, aliterature searchisbeingconducted todetermine ifthematterhaseve'rbeenstudied,andananalysisofthehydrogencombustion chemistry isbeingperformed.
Todate,theliterature searchhasnotturnedupanydirectinformation.
Theanalytical work,althoughstillincomplete, isindicating thatonceinertedagainstsparksorpyrotechnic
: ignition, amixturecannotbeshockinitiated.
Thisisthetypeofquestionthatlendsitselftoanalytical studywhere-indefiniteconclusions arepossiblebecausehydrogen-oxygen combustion isthebestunderstood ofallfuelsystems.Inaddition, weareexamining thequestionofwhatstructural effectswouldbeexpectedfromexplosion ofuninerted pocketsofH2-airozvariousdimensions.
Verytrulyyours,ATLANTICRESEARCHCORPORATION EdwardT.McHale,ManagerCombustion andPhysicalScienceDepartment ETM/blscc:StephenJ.MilotiAmericanElectricPowerServiceCorp.WilliamH.RasinDukePowerCompany ATTACHMENT 2TQAEP:NRC:00500 sj~~}}

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DONALDC.COOKNUCLEARPLANTUNITNOS.1AND2.ENCLOSURE TOAEP:NRC:00500 FIRSTQUARTERLY REPORTONHYDROGENISSUESgyp~~tkSO=3/5(',nn,(ging/g/IPOSI'g0"Ipt".~V-ofBscUmon5 R'aiJU~ORY INMETFfLE 1.INTRODUCTION InourresponsetoMr.D.G.Eisenhut's letterofSeptember 22,1980,submittal no.AEP:NRC:00476, datedOctober7,1980,AmericanElectricPowerServiceCorporation (AEP)described theeffortsunderwaytoinvestigate theneedforadditional hydrogencontrolcapability inIndiana8MichiganElectricCompany's DonaldC.CookNuclearPlant.OurletteralsostatedthatAEP,inconjunction withtheTennessee ValleyAuthority (TVA)andDukePowerCompany(Duke)wasinvolvedinaresearchanddevelopment programtoinvestigate additional hydrogencontrolmeasuresforpostulated accidents wellbeyondtheCookPlantdesignbasis.Thissubmittal isthefirstquarterly reportandprovides.thestatusoftheseeffortsandplannedanalytical andexperimental programs.

Thoseprogramsbeingjointlyperformed undertheauspicesoftheAEP/TVA/Duke TaskForcearedescribed inSection2below.EffortsuniquetoAEPandtheDonaldC.CookNuclearPlantaredescribed inSections4and5below.2.AEP/TVA/DUKE PROGRAMSINPROGRESS2.1FenwalI'nitorTests-Aseriesoftestswereperformed attheFenwalInc.Laboratories todetermine theignitioncharacteristics ofaGeneralMotorsAC(Model7G)'glowplug'ypeignitor.Theignitorwastestedinvariousmixturesofhydrogen, steam,andairandinthepresenceofwatersprayandfanflow.Representative

'safety-related'quipment (bothwithandwithoutinsulation) wasplacedinthetestvesselanditstemperature responsetohydrogencombustion monitored.

Theresultsofthistesting,whichhavebeenpreviously submitted totheCoranission byTVA,indicatethattheModel7Gglowplugisareliableignitionsourceforhydrogenconcentrations between6and12volumepercent.Thetemperature andpressuretransients duetohydrogencombustion andthehydrogenburnfractions observedduringthetestswereconsistent withpreviously publ'ished information.

Thebenefitofinsulating temperature sensitive equipment withathinsheetofaluminumfoilwasclearlyshownbythetests.2.2HALONFeasibilit StudTheAtlanticResearchCorporation (ARC)hasbeencontracted toperformafeasibility studyfortheuseofaHALONInjection Systemtosuppresshydrogencombustion inicecondenser containments.

TheARCstudyisexpectedtobecompleted byFebruary1,1981.Apreliminary reportbyARC(Attachment 1)indicates thatHALONdissolation maybeasignificant concerninapost-LOCA environment.

ItshouldbenotedthatthepHofapproximately 2.2indicated inAttachment 1doesnotaccountforthesodiumhydroxide additiveintheCookPlantContainment Spraysolutionwhichwould,ofcourse,resultinalessacidicsolution.

2.3Electroma neticInterference StudDr.B.E.Keiserhasbeencontracted toassesstheelectromagnetic interference (EMI)emissions fromasparkdischarge ignitor.Dr.Keiser'sstudyisexpectedtobe.completed byAprilI,1981.2.4CatalticCombustor StudTheAEP/TVA/Duke TaskForceisreviewing aproposalbyAcurexCorporation totestacatalytic combustor forpossibleuseinapost-accidentenvironment.

Thisdevicewouldbetestedunderaseriesofconditions ofvaryinghydrogenandsteamconcentrations bothwithandwithout'he presenceofpoisons.Ifpractical, acatalytic combustor wouldbeplacedonthedischarge ofeachofthecontainment airrecirculation fanstoeffectively controlhdyrogenconcentration withoutintroducing the.potential forwidespreadcombustion throughout thecontainment asisthecasewithaDistributed IgnitionSystem.2.5CLASIXImrovements TheAEP/TVA/Duke TaskForcehasgivenapprovaltoWestinghouse (W)OffshorePowerSystems(OPS)toimplement anumberofchangestoCLASIX.Inordertorealistically assessthecontainment responseofanicecondenser planttohydrogencombustion theexistingadiabatic burnmodels,whichleadtoexcessive conservatism inthepredicted results,shouldbemodified.

Thedurationofeachburnhasbeenestimated byCLASIXtobeintheorderofseconds;thisimpliesthatheattransferbetweenthecombustion regionanditssurrounding mightnotbenegligible.

Acontainment structure heatsinkmodelwillbeformulated andaddedtoCLASIXtoaccountfortheheatdissipated tothecontainment environment; heattransport bymeansofconvection andradiation willbeexplicitly modeled.Anylatentheatreleasedfromthecondensation processwillalsobeincludedintheenergybalancecalculation ofthecontainment.

Usingthemulti-layer conduction model,theaforementioned heattransfercorrelations willbeincorporated inCLASIXtomodelstructural heatsinks.IntheexistingCLASIXcalculations, airrecirculation fanflowcharacteristics andfancoolerperformance arenotmodeled.Theincor-porationoftheairrecirculation fan/headflowcurveintoCLASIXwillprovidebetter,flowdescriptions betweencompartments; asaresult,inter-compartment flowratescanbecharacterized bycompartment differential pressure.

Theoptionofusingthefancoolerswhicharedesignedtoremoveheatfromthecontainment duringnormalplantoperation willalsobeaddedtoCLASIX.Theseimprovements areattemptstoprovideamoreaccuratedescription ofthetemperature andpressureresponseofthecontainment intheunlikelyeventofhydrogencombustion.

Saidimprovements arescheduled tobecompleted byJanuary1981. 3.AEP/TVA/DUKE PROGRAMSPLANNEDInajointeffortwithEPRI,theAEP/TVA/Duke TaskForcehasunderconsideration aresearchprogram,to investigate variousaspectsofhydrogen-related issues;including ignitortests,parametric studiesofhydrogencombustion limits,andinvestigation ofprinciples ofhydrogenmixingandturbulence effects.Fourdifferent effortsarescheduled tostartinthefirstquarterof1981.Thedetermination ofthescopeandtestparameters forthesestudiesistobedecideduponbetweenEPRIandtheAEP/TVA/Duke TaskForceinJanuary1981.Thecurrentproposals fortheseprogramsandtheirschedules aresummarized below:3.1RockwellInternational Ignitordevelopment testswillbeperformed bythecontractor inwhichdifferent ignitortypesanddesignswillbetested.Thetestfacilityincludesacylindrical vessel,5footdiameterby6feetlongwithapressureratingof150psi.Sparkplug,hotsurfaceandcombustion waveignitorswillbeusedtoigniteleanmixturesofhydrogenandairundersteamorwatersprayenvironments.

Itistheintentofthisefforttoestablish combustion characteristics ofvariousignitorsandtoevaluatetheireffectiveness.

Alltestingiscurrently scheduled forcompletion byJune1981.3.2AECLllhiteshell Experiments willbeconducted ineitheran8-footdiametersphereora5-footdiameterby19-foothighcylinder.

l.Athydrogenconcentrations lessthan10Ã,experiments willbeconducted todetermine whethersizeandshapeofthevesselaffectstheextentofreaction.

Resultswillbecomparedwithdatacollected atWhiteshell ina2-litercylindrical vessel.2.Athydrogenconcentrations greaterthanlOX,thelaminarburningvelocityasafunctionofhydrogenconcentrations andtemperatures willbeverified.

Ignitionofuniformhydrogen/

air/steam mixtureswillbeinvestigated asafunctionofpressure, temperature andburnvelocities.

3.Turbulence effectsinacontainment whichmaybecausedbythermalconvection currentsorbyobstacles, suchaspipes,grids,etc.willbestudied.4.Flamepropagation fromonecompartment toanotheratvarioushydrogenconcentrations canalsobeinvestigated.

4-Thefirstmeetingtodiscusstheplanwiththetestingcontractor isscheduled forearlyFebruary.

Experiments areexpectedtobeginbyApril1,1981andfinishbyAugust1981.3.3AcurexCororationThecontractor willperformstudiesonmitigation phenomena suchastheeffectsofwaterspray,fogandHalononignitionandcombustion ofhydrogenandairmixtures.

Acylindrical vessel,78"ID,400cubicfeetwillbeusedin.thetest.Controlled amountsofhydrogen, air,steamandwaterspraycanbeintroduced inthetestvesseltosimulatevariouspostulated conditions.

Different typesofigniterscanalsobeinstalled inthetestsectiontobetested.Uniformhydrogenconcentration withinthetestvesselisensuredbytheoperation ofacirculation fan.Provisions canbemadeavailable toobtainphotographic recordsofthecombustion process.Contractnegotiation isscheduled tobegininJanuaryof1981andthefirsttestisexpectedtostartinApril.Theexperimental programisduetobecompletebyJuly1981.3.4HEDLTestswillbeconducted attheHEDLContainment SystemTestFacility.

Thesetestswillnotinvolveignitionofthetestvolume.Theprimarypurposeofthisstudyistoinvestigate hydrogenmjxing,stratification anddistribution inalargeopenvolume(30,000ft~).Parameters whichaffectthedistribution andmixingofhydrogenwillbeexamined.

Theyinclude:thermalgradients, effectsofsprays,steam,naturalandforcedconvection effects.Compartments canalsobeformedwithinthelargevolumetostudyhydrogendistribution undervariousconditions.

Detailsoftheexperimental programwillbediscussed inaforth-comingmeetingplannedforJanuarywithinvestigators fromHEDL.ThetestprogramisexpectedtobeginonMarch1,1981andconcludebyJune1981.'.REPORTONAEPSPECIFICWORK4.1CLASIXAnalsesforCookPlantTheCookPlanticecondenser containment responsetohypothetical hydrogenburntransients hasbeenanalyzedutilizing theWestinghouse/

OffshorePowerSystems'OPS)

CLASIXcomputercode.TheresultsoftheCookPlantanalysesarecontained intheattachedOPSreportentitled"SummaryofAnalysesofD.C.CookContainment ResponsetoHydrogenTransients" (Attachment 2).

Vt\

Theinitial(pre-hydrogen generation) containment conditions inputtoCLASIXwereobtainedfromtheWestinghouse LOTICcomputercode.Thehydrogengeneration ratefortheS2DsequencewasobtainedfromtheMARCHcomputercodeaswerethetimedependent massandenergyreleaseratesfromthepostulated break.Theassumptions utilizedintheCLASIXanlaysesareconsistent withthoseusedintheTVAandDukestudies.Parameters specifictotheCookPlant,suchasfanflowratesandflowlosscoefficients betweencompartments, aresummarized inTableNos.3and4oftheOPSreport.UnliketheTVAandDukeCLASIXstudies,theCookPlantcalculational modelincludedaseparatenodalvolumerepresentative ofthetwofan/accumulator roomsandaccounted forthepresenceofcontainment spraycapability inboththelowercompartment andthefan/accumulator rooms.Thesignificance ofthesedifferences isdiscussed inSection4.2below.EFourcaseswereexaminedbyCLASIXinwhichthecriteriaforignitionandflamepropagation werevaried.Asummaryoftheresultsofthesecasesiscontained inTable5oftheOPSreport.Thefirstcase,JVAC1,doesnotaccountforcontainment sprayflowinthelowercompartment andfanaccumulator rooms.Thiscase,whichisnottypicaloftheCookcontainment, wasanalyzedtoobtainbaselineinformation sufficient to"allowcomparison withtheTVAandDukestudies.Theremaining threecasesaccountforspray,flowinthelowercompartment andthefan/accumulator roomsaswellastheuppercompartment andarereflective oftheCooksystems.4.2Evaluation ofCLASIXResultsReviewoftheOPSreportindicates thatthepresenceoflowercompartment sprayshasa.significant beneficial effectonthecontainment responsetohydrogencombustion.

Themostnotableeffectsarethereduction ofthepeaktemperature inthelowercompartment byafactorofapproximately two(relative totheJVAC1case)andthetemperature reduction betweenburns.Itisalsoapparentthatthisadditional spraycapability effectively reducestheamountoficemeltedasaresultofahydrogenburn(s).Reviewofthetimedependent temperature transients inthefan/accumulator roomsandthedead-ended volumeforcasesJVAC2,JVAC3,andJVAC4suggeststhathydrogenignitioninside,orflamepropagation into,theseareasishighlyunlikely.

Inonlyoneinstance(JVAC3)doesthepeaktemperature ineitherofthoseareasexceed270oF.TheJVAC3casepredictstwotemperature spikesinthefan/accumulator rooms.Thesespikes,showninFigure26ofthe OPSreport,appeartobeofveryshortduration.

Therelativenon-susceptibility oftheseareastotheadverseenvironment associated withhydrogenburningisaveryimportant factortobeconsidered whenevaluating equipment survivability.

Itwasprecisely forthatreason;todetermine theenvironmental conditions intheseareasduringhydrogentransients, thattheCookPlantcalculational modelwasmodifiedtoincludeaseparatefan/accumulator roomnodalvolume.Anindependent evaluation oftheCLASIXresultsisbeingperformed byAEP.Theintentofthiseffortistoprovideareviewoftheassumptions andtheanalytical methodusedinCLASIX.Veryimportant information oncontainment responseresulting fromhydrogencombustion hasbeenprovidedbythecomputercode;however,inordertofullyutilizethedata,verification willberequired.

Forinstance, CLASIXresultsindicatethatthereareaseriesofburnsoccurring whenever;.

thereiscombustion insideacompartment, themultiplicity ofcombustion andthedurationtimeofeachburnwouldhavetobeevaluated toensurethattheyreflecttheactualphenomenon andnotthenumerical oranalytical schemethatischoseninthecode.Propagation toadjacentchambersispresently artificially imposedinthecodeandthusconditions forflamepropagation arenotexplicitly modeled.TheAEPreviewwillattempttoidentifysomeofthelimitations ofthecodewherebyCLASIXresultscanbemoreaccurately interpreted andapplied.4.3CLASIXResultsYs.Containment UltimateStrenthPreliminary calculation ofthecontainment ultimatestrengthshowsthatunderthestaticloadassumption, thelimitofthecontainment shellis69.7psiaandtheequipment hatchisestimated tobe40.8psia.Itisprudenttorecallthattheselimitswerecomputedbasedoncertainconservative assumptions; forinstance, theselection ofmaterialstrength.

CLASIXresultstabulated inTable5,Attachment 2,withcompletecombustion, predicted that10v/ohydrogenmixturethecontainment willexperience apeakpressureof27.5psiawhereasan85hydrogencombustion willyieldapeakpressureof25.0psia.According toCLASIX,bothofthesemaximawilloccurintheicecondenser withtheuppercompartment experiencing apressurepeakofasimilarmagnitude.

Abouta10Kreduction inmaximumpressureinthelowercompartment isreported.

Thehighestpressurecalculated byCLASIXis33.5psiaoccurring intheuppercompartment undera10$combustion withflamepropagation criterion toadjacentcompartment at8v/o.A31.0psiapeakispredicted insidetheicecondenser and26.5psiapeakinthelowercompartment.

BasedonCLASIXandultimatecontainment strengthcalculations, themaximumpeakcontainment pressurepredicted invariousselectedhydrogencombustion scenarios isconsistently belowtheultimatestaticpressurecapacityofthecontainment ascalculated byStructural Mechanics Associates.

Furtherstudiesarebeingconducted toassesswithimprovedcertainty therelationship betweenhydrogencombustion containment responseanditsultimatestrengthcapability.

5.COOKCONTAINMENT ULTIMATECAPABILITY 5.1OverviewofCookContainment Structural DesinBeforediscussing theAEPcommentsontheNRCconsultant's reportontheultimatepressurecapability oftheCookcontainment andAEP'sowncalculation, abriefsummaryisgiveninthisSectionofthestructure designfeaturesrelatedtoultimatecontainment strength.

TheDonaldC.CookNuclearPlantcontainment buildingisasteellinedreinforced concretecylindrical structure withahemispherical domeandaflatbasemat.Thenormalconcretestrengthis3500psiat28days.Thereinforced concretebasemathasanaveragethickness of10'-0".Thetopofthefoundation matislinedwith4"thicksteelplateandtheplateiscoveredwithatwofootthickreinforced concreteslab.Thecylinderhasadiameterof115'-0"insidetoinsideofthe3/8"thickliner.Thereinforced concretewallsare4'-6"thickatthebasemattaperingto3'-6"atsevenfeetabovethebaseandcontinuing at3'-6"tothespringlinewhichis113feetabovethebasemat.Thereinforced concretedomehasaninsideradiusequivalent tothatofthecylinder.

Theconcretethickness ofthedomevariesgradually from3'-6"atthespringlineto2'-6"atthepeak.Thebasematismadeintwolayerswhicharetiedtogetherbymeansof811reinforcing barsspacedat6'-0"oncenter.Thereinforcing inthecylinderwallsisgenerally tworowsof818at12"oncentercircumferentially andfourrowsof818at9"oncenterto14'-0"abovethebase;fourlayersof818at9"oncenterbetween14'-0"and21'-0"abovethebase,twolayersof818at18"oncenterbetween12'-0"andthespringline.Additionally, therearefourlayersofdiagonally oriented818at36"oncenterreinforcing.

Thereisalsoshearreinforcing inzonesbetweenthebaseslabelevation andapproximately 15'bovethebaseandagain,35'o56'bovethebaseslab.Shearreinforcing isagainprovidedatthespringline.

LLThedomehoopreinforcing consistsoftwolayersof818at12"oncenterto35abovethespringline,andthentwolayersof818at18"oncenterfrom35otothepeak.Meridional reinforcing consistsoftwolayersof//18at18"plusonelayerof811at18"to50abovethespringline.Therearetwolayersof818at18"from50tothepeak.Additionally, therearefourlayersofdiagonally oriented818at36"oncenterplacedto20oabovethespringlineandshearreinforcing to10'bovethespringline.There-barisASTM-615Grade40.The'linerisASTMA442Grade60.Thepersonnel hatchisa10'-0"diagonalbarrelanchoredintothecontainment cylinderwall.Theequipment hatchisa20'-0"diagonalbarrelanchoredintothecontainment cylinderwallandhavinga10'-0"diagonalpensonnel airlockinsert.Theequipment hatchbarrelandthepersonnel hatchbarrelareeachanchoredtothecontainment bymeansoftwo3/4"thickcollars.Thematerials ofthepersonnel andequipment hatchesareASTHA516Grade70andASTHA193'rade B7forthebolting.ThematerialoftheanchoredbarrelisASTMA300fireboxA516Grade70.5.2CommentsonDr.Harstead's ReortItem1ofAttachment 3tothisreportcontainscommentsbyDr.J.D.Stevenson ofStructural Mechanics Associates (SMA}onDr.Harstead's report.5.3AEPSecificCalculation ResultsItem2ofAttachment 3containsasummaryofAEPcontainment analysespresently underway.

5.4Dr.Stevenson's Presentation atDecember181980MeetinItem3ofAttachment 3containsasummary,including slides,ofthepresentation givenbyDr.Stevenson attheAEP-NRCmeetingheldinBethesda, MarylandonDecember18,1980.6.DISTRIBUTED IGNITIONSYSTEMDESIGNSTUDYAsstatedinourAEP:NRC:00476 submittal, AEPisproceeding withadesignstudyforinstallation ofaDistributed IgnitionSystem(DIS}intheCookPlantcontainments.

Toasgreatanextentaspossible, theCookDISdesignparallels theSequoyahandMcGuiredesigns.Itisourintention toinstallthein-containment portionoftheDISduringthe1981refueling outages,ifrequiy;ed. TheDISconsistsofsixty-eight igniterassemblies locatedindistinctareasofthecontainment building.

Twoigniterassemblies, onefromeachofTrains'A'nd'B',shallbelocatedineachofthirty-four designated areas.Eachigniterassemblyconsistsofathermalresistance heatingelement(glowplug),GeneralMotorsACPlugType7G,andaDonganElectricControlPowerTrnasformer (Model52-20-435).

Theglowplugandtransformer aremountedinasealedboxwhichemploysheatshieldstominimizethetemperature riseinsidetheboxanda'dripshield'oreducedirectwaterimpingement onthethermalelement.6.1DISDesinCriteriaTheintentof.aDISistoreliablyinitiatecombustion ofrelatively leanhydrogenmixtures.

The.'following criteriawereusedintheselection oftherecommended igniterlocations contained above.1.Allproposedigniterlocations areinareaswellmixedbythehydrogenskimmer/air recirculation fansystems.2.Ingeneral,ignitersshouldbemountedneaitheceilingwithinagivenvo'lume.3.Alligniterswiththeexception ofthoseinthevicinityofthePRTaretobelocatedabovemaximumflood-uplevel.4All.DIS.cables..installedmnside.

containment.

mustbeyJatectedLfrom

.orqualified towithstand theenvironment associated withasmallLOCAandhydrogencombustion.

5.AllDIScablesoutsidecontainment mustbeprotected fromorqualified towithstand theenvironment associated withaworstcasehighenergylinebreak.6.Trains'A'nd'B'ftheDISaretobeelectrically isolatedfromeachother.7.DIScomponents aretobesupported toSeismicCategoryIstandards.

6.2IniterLocations Thepreliminary DISfortheCookPlanthasignitersinthefollowing locations; equallydistributed betweenTrains'A'nd'B': AreaLowerVolumeNo.ofIniters12AroximateLocationUniformly spacedaroundthebiological shieldwall.LowerVolumeFanRooms(2)InthevicinityofthePRTrupturedisk.Fourigniters(ineachF/Aroom)equallyseparated withinthevol.ume.SG8PREnclosures 10Twoignitersinsideeachofthefiveenclosures.

UpperVolumeUpperVolume1210Locatedintheupperdomearea;uniformly spaced.TwoigniterslocatedontheoutsideoftheSG&PZRenclosures.

IceCondenser 14Twoigniterseachintheupperplenumareaof6ayNos.3,6,9,12,15,18,and21;mountedonthecontainment wall. 7.ELECTRICHYDROGENRECOMBINERSWestinghouse, attherequestofAEP,hasinvestigated thepotential forincreasing electrichydrogenrecombiner (EHR)capacitytotheextentnecessary tomitigatedegradedcore/hydrogen events.Westinghouse hasdetermined thataninordinate numberof(theequivalent ofseveralhundred)EHRswouldberequiredtoprovidesufficient hydrogenrecombina-tioncapacitysoastomitigateaneventinwhichthehydrogenfrom75w/ozirconium oxidation isreleasedtothecontainment (linearly) overaneighthourtimeperiod.Itisimportant torealizethattheabovecalculation doesnotaccountinanywayfortheignitioncapabilities ofthepresently installed EHR;whichare,ineffect,large-sized glowplugs.Itwouldbereasonable toexpecttheEHRstoactasignitionsourcesifandwhenthehydrogenconcentration exceededthe'recombination'evel.

CLASIXanalysesmightbeperformed toevaluatetheeffectiveness ofdeliberate

ignition, bytheEHRs,onlyintheuppervolume.

~)~ATTACHMENT 1TOAEP:NRC:00500

,C,I~IAN'TICRESEARCHCOR90RATION~

5390CHEROKEEAVENUE~AIEXANORIAVIRGINIA'2%4

~703-642-4000

.WX710-832-628November26,1980Dr.WangLauTennessee ValleyAuthority 400CommerceAvenueKnoxville, TN37902

Reference:

ContractTV-55205A

-"SystemFeasibility AnalysisofUsingHalon1301inanIceCondenser Containment"

DearDr.Lau:

Thissummaryletterreportisbeingsubmitted perthecontractrequirement, toprovideaninterimreportinthecourseofthepxogram.UptothepresenttimeavisitwasmadetotheWattsBarplantbyfivetechnical personsassociated withthestudy,numeroustelephone discussions havebeenheldwithTVA,AEPSCand'ukePowerpersonnel, andagroupfromDukePowervisitedAtlanticResearchforareviewoftheHalonsystemandouropinionaboutalternative approaches.

Wehavehadrequeststoaccelerate progressifpossible, whichwearetryingtoaccommodate but,asexplained, muchoftheworkfollowsasequential pathandcertaintaskscannotbecompleted untilotherpriorworkhasbeenperformed.

Inbroadsummary,itcanbereportedthataHalon1301systemiscertaintobeabletoprovidefullsafetyagainstanypossiblehydrogenhazardfollowing aLOCAinanicecondenser containment.

Thematterthatremainsdoesnotconcernsafetyacceptability, butratherconcernsthequestionofhowmuchcorrosion mightcertainmaterials besubjected to,andwilltheprimaryandsecondary systemsmeetspecifications andberecoverable afteraLOCAiftheywereexposedtoHalondecom-positionproducts.

Briefly,thecorrosion pxoblemisasfollows:Halonitselfisstableandinerttowardmaterials.

However,ifneededfollowing aLOCA,Halongascoulddis-solvetoasmallextentintheemergency coolingwater(itssolubility is150ppmbyweightinwaterat77'Fand0.5atm).Radiolytic decomposition canthenoccur,theresultof.whichcouldbetheformation ofbromides(andfluorides) inlowcon-centration (about400ppmBr)inthewater.Therefore, thequestionbeingaddressed iswhateffectsuchasolutionwillhaveonreactormaterials, particularly stainless steels.Ifunfavorable answersemergefromthematerials study,thentheoptionsarethefollowing:

~PlantoinstallaHalon1301systemtoprovidesafetyduringtheinterimwhileanalternative systemisbeingdeveloped, usingtherationale thatthelikelihood ofhavingtoemployHalonisextremely small.

(contract TV-55205A InterimReportPageTwo~Studytheeffectofexposureofstainless steelstohydrogen.

Sincehydrogenhasanembrittling effectonsteels,itmaybethathydrogenaloneisdeleterious enoughthatthereactorsystemcouldnotbere-coveredanyway,evenifHalonwerenotused.~Investigate meansofeliminating orreducingtheeffectofbromides.

Thegeneralapproachwouldbetofindadditives thatdefeattheHalonradiolytic decomposition mechanism insolution.

Severalcandidate approaches havebeenconsidered:

Determine ifHalondecomposes insolutioninthepresenceofhydrogenasrapidlyasinitsabsence.HydrogenmaycompetewithHalonforsolvatedelectrons, thespeciesresponsible forinitiating Halondegradation.

Addanadditivetothewaterthatwillprecipitate bromideininertform.(Asearchforcandidate additives willbemade.)Addanadditivetothewaterthatwillproducehydroxylradi-calsinsolution.

Theseradicalsarethoughttoreactwithbromideionstoreversethedecomposition reaction.

Alcoholsmaybegoodcandidates.

Determine whetherdecomposition ofHalonwilloccurtothesameextentoverarangeofpHvalues.Generally attempttofindadditives thatmaybeeffective inreversing Halondegradation.

Substantial progresshasbeenmadeonthreetasksoftheprogramandeachoftheseisreviewedbelow.SstemDesinIfnocreditisallowedforsteaminerting, itwillrequire191,600lbmassofHalon1301toinertthetotalcontainment, including upperandlowercompart-mentsandicecondenser plenums(1.2x106ft3).TheHalonrequirement isderivedfromtheflammability dataobtainedinthepreviousARCstudyandtheassumption of75%zirconium claddingreactionreleasing 1450lbmassofhydrogen.

Assumingnegligible lossesandspecifying a20%excess,thetotalHalonrequirement willbe230,000lb.Neglecting lossesis)ustified

.becausethecontainment leakrateisessentially zero,andthelosstocoolingwateris4540lbviaHalondecompo>>sitionand880lbthroughdissolution.

Thecontainment partialpressures willbe(70'Fbasis):H2Halon1.000atm=14.70psia0.234atm=3.44psia0.493atm=1.727atm=25.33psia=10.7psig ContractTV-55205A InterimReportPageThreeAstorageandpipingconfiguration hasbeend'esigned whichisbasedontheguidingprinciple thatthesystemmustfunctionproperlyeveniftwoindependent malfunctions occursimultaneously.

TheHalonwouldbestoredinfive316stain-lesssteeltanks,fourofwhichwouldcontaintherequired230,000lbandaniden-ticalfifthback-uptankwouldcontain57,500lb.ThestoragetanksaresizedtocontaintheHalonattemperatures inexcessof130'Fwheretheliquiddensityis77.6lb/ft~Eachtankwouldhaveanequivalent spherical diameterof12feet3withawallthickness ofthreeinches.Thisprovidesaworkingpressureof600psigforthesystem,conforming toSectionVIIIoftheASMEUnifiedPressureVesselCode.Eachtankwouldhaveanassociated tankofnitrogengasconnected toitwhichwouldmaintainadeliverypressureof600psigiftheHalonhadtobedischarged.

ThefiveHalontanksarevalvedindependently totwomanifolds offour-inch.

SSSchedule40pipe.(Themanifoldpipingdiametermayhavetobelargerifatotalrunofmuchmorethan300-400feetisrequired,),

Twopenetrations ofthecon-tainmentwillberequiredforthefour-inch pipes.ThepipingwillconformtoANSIB-31.10classification.

Insidethecontainment, thepipingbranchestotheupperandlowercompartments, eachaccumulator compartment andtheinstrument roomtomaximizecoverageofisolatedcompartments.

Anarrayofspraynozzlescomesoffeachmanifoldpipeinsidethecontainment.

Therequirement isto,deliver 230,000lbHalonin1000secondsor1330gpmat130'F.Onearrangement toaccomplish thisistouse20fullconenozzlesof15/32"orificeoneachmanifold, oneofwhichissufficient.

Thisfeatureofthesystemdesignisbeingleftopenatpresent.Theexactnozzlesystemconfiguration would.havetobedetermined byactualinspection ofthecontainment and'computation oftherequire-ment.ineacharea.Thefinalreportwillpresentthesystemdesigninmuchgreaterdetail.Otheraspectsofthedesignarealsobeingworkedon,including instrumental analysisre-quirements.

HalonDecomositionandBromideIonConcentration Sincethenetdecomposition ofHalonceasesatequilibrium Brconcentration of5.2x103moles/1,thetotalquantityofHalondecomposed depends(atequili-brium)uponthetotalquantityofwaterinthecontainment (6.46x103lbsHalondecomposed pergallon,ofwater).Forthemaximumamount(702,950gallons,re:TVAletterofOct.31,1980),thequantityofHalondecomposed is4540lb,independent ofthefissionproductreleasetothewater.Anadditional 880lbwillremaindis-solvedinthewater.TherateofHalondecomposition alsodependsuponthequantityofwaterinthecontainment.

Thetime-dependent quantityofHalondecomposed forseveralpotential valuesofthecontainment waterinventory hasbeencomputedandwillbegiveninthefinalreport.Decomposition ofHalonyieldsBrinsolutionwhichactsasascavenger fortheOHradicalandtendstosuppressfurtherHalondecomposition.

Equilibrium isattainedataBr-concentration of5.2x103moles/liter also.

ContractTV-55205A InterimReportPageFourWaterChemistrandHBr-ispresumably formedasHBranddecomposition ofHalonalsoproducesHFatconcentrations 3timesthatofHBr.HFionization, however,issuppressed bytheH+fromHBrionization, andatequilibrium mostoftheHFisundissociated.

ThepHchangesdependupontheinitialchemicalcomposition andpHofthewaterinthecontainment system.Althoughthesystemwaterwilllikelybeslightlyalkaline(pH>7)andperhapsbuffered(presence ofsodiumborate,forexample,topreventcritica1ity),

calculations ofthepHchangeshavebeenmade,conservatively assumingpurewater(pHof7.0)inthecontainment systeminitially.

Assumingcom-pleteionization ofHBrandanionization constantof3.53x10"4forHF,there-sultingpHatequilibrium wouldbe"2.2,determined principally bytheHBr,withHFionization largelysuppressed.

Hydrogen-air mixturescanbeinertedagainstcombustion byadditionofHalon.1301,andalargebodyofdataontheflammability limitsofsuchmixtureshasbeendeveloped previously usingsparksandsquibsasignitionsources.Thequestionhasarisenastowhetherashockwavecouldignitemixturesthataresoinerted.'nordertoanswerthisquestion, aliterature searchisbeingconducted todetermine ifthematterhaseve'rbeenstudied,andananalysisofthehydrogencombustion chemistry isbeingperformed.

Todate,theliterature searchhasnotturnedupanydirectinformation.

Theanalytical work,althoughstillincomplete, isindicating thatonceinertedagainstsparksorpyrotechnic

ignition, amixturecannotbeshockinitiated.

Thisisthetypeofquestionthatlendsitselftoanalytical studywhere-indefiniteconclusions arepossiblebecausehydrogen-oxygen combustion isthebestunderstood ofallfuelsystems.Inaddition, weareexamining thequestionofwhatstructural effectswouldbeexpectedfromexplosion ofuninerted pocketsofH2-airozvariousdimensions.

Verytrulyyours,ATLANTICRESEARCHCORPORATION EdwardT.McHale,ManagerCombustion andPhysicalScienceDepartment ETM/blscc:StephenJ.MilotiAmericanElectricPowerServiceCorp.WilliamH.RasinDukePowerCompany ATTACHMENT 2TQAEP:NRC:00500 sj~~

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