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{{#Wiki_filter:DONALDC.COOKNUCLEARPLANTUNITNOS.1AND2. | {{#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. | 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- | '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\ | Vt\ | ||
Theinitial(pre- | 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. | ||
,C,I~IAN'TICRESEARCHCOR90RATION~5390CHEROKEEAVENUE~AIEXANORIAVIRGINIA'2%4~703-642-4000.WX710-832-628November26,1980Dr. | 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-" | |||
ContractTV-55205A | |||
-"SystemFeasibility AnalysisofUsingHalon1301inanIceCondenser Containment" | |||
==DearDr.Lau:== | ==DearDr.Lau:== | ||
Thissummaryletterreportisbeingsubmitted perthecontractrequirement, toprovideaninterimreportinthecourseofthepxogram.UptothepresenttimeavisitwasmadetotheWattsBarplantbyfivetechnical personsassociated withthestudy,numeroustelephone discussions havebeenheldwithTVA,AEPSCand'ukePowerpersonnel, andagroupfromDukePowervisitedAtlanticResearchforareviewoftheHalonsystemandouropinionaboutalternative approaches. | |||
( | Wehavehadrequeststoaccelerate progressifpossible, whichwearetryingtoaccommodate but,asexplained, muchoftheworkfollowsasequential pathandcertaintaskscannotbecompleted untilotherpriorworkhasbeenperformed. | ||
ContractTV- | 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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Issue date: | 01/12/1981 |
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Text
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~~