ML17326B152

Post-Accident Core Damage Assessment Methodology.

ML17326B152
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Site:	Cook
Issue date:	08/31/1984
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D.C.COOKPOSTACCIDENTCOREDAMAGEASSESSMENTMETHODOLOGY840SO50aSO84083iI!'"PDRADOCK050003i5,,',',PDRAugust,1984

NOTICE~~~TheD.C.CookPostAccidentCoreDamageAssessmentMethodologyReportconsistsofusingtheWestinghouseOwner'sGroupRevision1genericreportandmodifyingittoincluderelevant0.C.Cookplantspecificparameters.Whereachangeinthetextofthegenericreporthasbeenmadetoincorporateplantspecificinformation,brackets,t'],havebeenusedtoindicatethechange.Inthegenericreportthelastsectionconsistedofastep-by-stepexampleontheuseofthecoredamageassessmentmethodology.Inthisreporttheexamplesectionisreplacedwithaprocedurespecificto0.C.Cook.Alsoincludedisanexampleofthisprocedure.

TABLEOFCONTENTSINTRODUCTIONANDPURPOSE1.1Methodology2.0TECHNICALBASISFORCOREDAMAGEASSESSMENTMETHODOLOGY2.1CharacteristicFissionProducts2.22.3CoreInventoriesPowerCorrectionforCoreInventories2.3.1PowerCorrectionFactor2.4RelationshipofCladDamageWithActivity2.4.1GapInventory02.4.2SpikingPhenomena2.4.3ActivityAssociatedWithCladDamage2.4.4GapActivityRatios2.4.5AdjustmentstoDetermineActivityReleased2.5RelationshipofFissionProductReleaseWithOvertemperatureConditions2.6RelationshipofNuclideReleaseWithCoreMeltConditions2.7Samp1ingLocations71010101326264043463.0AUXILIARYINDICATORS3.1ContainmentHydrogenCon'centration3.2CoreExitTemperaturesandReactorVesselWaterLevels3.3ContainmentRadiationHonitorsandCoreDamage535357604.0GENERALIZEDCOREDAMAGEASSESSHENTAPPROACH655.0'IMITATIONS6

76.0REFERENCES

69APPENDIXACoreDamageAssessmentProcedureAPPENDIXBExampleofCoreDamageAssessmentProcedure LISTOFTABLESTitle~Pae2-1SelectedNuclidesforCoreDamageAssessmentFuelPelletInventoryforWestinghousePlantsGapInventory2-3-1GapInventoryHinimumandHaximum122-42-5ExpectedIodineSpikeNormalOperatingActivityIsotopicActivityRatiosofFuelPelletandGap27Parent-DaughterRelationships37SourceInventoryofRelatedParentNuclides392-9ExpectedFuelDamageCorrelationwithFuelRodTemperature412-10PercentActivityReleasefor100PercentOvertemperatureConditions422-11PercentActivityReleasefor100PercentCoreHeltConditionsSuggestedSamplingLocations52,3-1AverageContainmentVolumeandZirconiumHass56InstantaneousGammaRaySourceStrengthsDuetoa100PercentReleaseofNobleGasesatVariousTimesFollowinganAccident61 LISTOFTABLES(continued)TebleTitle~Pae3-2AInstantaneousGammaRayFluxesDueto1004ReleaseofNobleGasesatVariousTimesFollowinganAccident62CharacteristicsofCategoriesofFuelDamage66 LISTOFFIGURES~FiureTitle~Pae2-1PowerCorrectionFactorforCs-134BasedonAveragePowerDuringOperation2-2Relationshipof5CladDamagewith5CoreInventoryReleasedofXe-133152-3Relationshipof5CladDamagewith5CoreInventoryReleasedofI-13116RelationshipofXCladDamagewithXCoreInventoryReleasedofI-131withSpiking172-5Relationshipof5CladDamagewith5CoreInventoryReleasedofKr-8718Relationshipof5CladDamagewith%CoreInventoryReleasedofXe-131m192-7RelationshipofXCladDamagewithXCoreInventoryReleasedofI-132202-8Relationshipof5CladDamagewithACoreInventoryReleasedofI-133212-9Relationshipof5CladDamagewith5CoreInventoryReleasedofI-135222-10WaterDensityRatio(Temperaturevs.STP)2-10ASumpMaterVolumeVersusSumpLevelIndication2-10B1ContainmentWaterVolumeVersusSumpLevelIndication,J35 LISTOFFIGURES(continued)~FtereTitlePacae2-11RelationshipofgFuelOvertemperaturewithXCore'nventoryReleasedofXe,Kr,I,orCs2-12RelationshipofXFuelOvertemperaturewith5CoreInventoryReleasedofBaorSr452-13RelationshipofAFuelHeltwithX,CoreInventoryReleased4BofXe,Kr,I,Cs,orTe2-14Relationshipof%FuelHeltwith5CoreInventoryReleased49ofBaorSr2-15RelationshipofXFuelHeltwith%CoreInventoryReleased50ofPr3-1ContainmentHydrogenConcentrationBasedonZirconiumWaterReaction55DistributionofThermocouplesandFluxThimblesforUnit158andUnit2PercentNobleGasesinContainmentforUnit1andUnit264

1.0INTRODUCTION

ANDPURPOSEInMarch1982theNRCissueda"PostAccidentSamplingGuideforPreparationofaProceduretoEstimateCoreDamage"asasupplementtothepostaccidentsamplingcriteria,ofNUREG-0737.Thestatedpurposeofthisguidewas(1)toaidutilitiesinpreparationofamethodologyforrelatingpostaccidentcoredamagewithmeasurementsofradionuclideconcentrationsandotherplantindicators.TheprimaryinterestoftheNRCwas,intheeventofanaccident,tohavesomemeansofrealisticallydifferentiatingbetweenfourmajorfuelconditions:nodamage,claddingfailure,fueloverheating,andcoremelt.Themethodologydevelopedisintendedtoenablequalifiedpersonneltoprovideanestimateofthisdamage.InordertocomplywiththeNRCrequestforsuchamethodology,Westinghouse,undercontracttotheWestinghouseOwnersGroup(WOG),preparedthegenerictechnicalreport'.$13)1ThisreportiscognizantofNRC'sinitialintention.Additionally,thereportreflectsinputbyNRCandvariousrepresentativesoftheWOGprovidedduringseveralmeetingsheldonthissubjectduringthepastyear.tThisreporthasbeenarrangedtopresentthetechnicalbasisforthemethodology(Section1through5),andtoprovideaprocedurebasedonthismethodology(AppendixA).1.1METHODOLOGYTheapproachutilizedinthismethodologyofcoredamageassessmentismeasurementoffissionproductconcentrationsintheprimarycoolantsystem,andcontainmentwhenapplicable,obtainedwiththepostaccidentsamplingsystem.Greaterreleaseoffissionproductsintotheprimarycoolantcanoccurifinsufficientcoolingissuppliedtothefuelelements.Thosefissionproductscontainedinthefuelpellet-fuelcladdingintersticesarepresumedtobecompletelyreleaseduponfailureofcladding.Additionalfissionproductsfromthefuelpelletareassumedtobereleasedduringovertemperatureandfuelmeltconditions.Theseradionuclidemeasurements, togetherwithauxiliaryreadingsofcoreexitthermocoupletemperatures,waterlevelwithinthepressurevessel,containmentradiationmonitors,andhydrogenproductionareusedtodevelopanestimateofthekindandextentoffueldamage.

2.0TECHNICALBASISFORCOREDAMAGEASSESSMENTMETHODOLOGY2.1CHARACTERISTICFISSIONPRODUCTSDependingontheextentofcoredamage,characteristicfissionproductsareexpectedtobereleasedfromthecore.Anevaluationwasconductedtoselectthefissionproductisotopeswhichcharacterizeamechanismofreleaserelativetotheextentofcoredamage.Nuclideswereselectedtobeassociatedwiththecoredamagestatesofcladdamage,fueloverheat,andfuelmelt.Theselectionofnuclidesforthismethodologywasbasedonhalf-life,energy,yield,releasecharacteristics,quantitypresentinthecore,andpracticalityofmeasurementusingstandardgammaspectrometrytechniques.Thenuclidesselectedforthismethodologyhavesufficientcoreinventoriesandradioactivehalf-livestoensurethattherewillbesufficientactivityfordetectionandanalysisofthenuclidesforsometimefollowinganaccident.Mostofthenuclidesselectedhavehalf-liveswhichenablethemtoreachequilibriumquicklywithinthefuelcycle.Thelistofselectednuclidescontainsnuclideswithhalf-livesof1dayorlesswhichareassumed/toreachequilibriuminapproximately4days.Thesenuclidesareusedtoassesscoredamageforcoresthathavebeenoperationalinagivencycleforlessthanamonth.Forcoresthathavebeenoperatingformorethanamonth,thelistcontainsnuclideswithhalf-livesgreaterthan1daywhichreachequilibtiumatsometimeduringthefirstmonthofoperationdependingonthehalflifeofthenuclide.BothgroupsofnuclidesareusedtoassesscoredamageForcoresthathavebeenoperationalinagivencycleformorethanamonth.Otherfactorsconsideredduringtheselectionprocessweretheenergyandyieldofthenuclidesalongwiththepracticalityofdetectingandanalyzingthenuclides.Nuclideswerechosenbasedontheirreleasecharacteristicstoberepresentativeofthespecificstatesofcoredamage.TheRogovinReport(2)notedthatasthecoreprogressedthroughthedamagestatescertainnuclidesassociatedwitheachdamagestatewouldbereleased.Thevolatilityofthenuclidesisthebasisfortherelationshipbetweencertainnuclidesandaparticularcoredamagestate.

Alistoftheselectednuclidesforthiscoredamage.assessmentmethodologyisshowninTable2-1.2.2COREINVENTORIESImplementationofthecoredamageassessmentmethodologyrequiresanestimationofthefissionproductsourceinventoryavailableforrelease.ThefissionproductsourceinventoryofthefuelpelletwascalculatedusingtheORIGENcomputercode,basedonathree-regionequilibriumcyclecoreatend-of-life.Thethreeregionswereassumedtohaveoperatedfor300,600,and900effectivefullpowerdays,respectively.Foruseinthismethodologythefissionproductinventoryisassumedtobeevenlydistributedthroughoutthecore.Assuch,thefissionproductinventorycanbeapplicabletootherequilibriumcoreswithdifferentregionalcharacteristics.Thefuelpelletinventoryoftheselectedfissionproductsandsomeadditionalfissionproductsofinterestfor0.C.CookUnit1andUnit2isshowninTable2-2.2.3POWERCORRECTIONFORCOREINVENTORIESThesourceinventoryshowninTable2-2presentsinventoriesforanequilibrium,end-of-lifecorethathasbeenoperatedat100percentpower.Forthismethodologyasourceinventoryatthetimeofanaccidentthataccountsforthepowerhistoryisneeded.Forthosecaseswherethecorehasreachedequilibrium,aratioofthesteadystatepowerleveltotheratedpowerlevelisapplied.Withintheaccuracyofthismethodology,aperiodoffourhalf-livesofanuclideissufficienttoassumeequilibriumforthatnuclide.Fornuclideswithhalf-liveslessthanonedaythepowerratiobasedonthesteady-statepowerlevelofthepriorfourdaystoreactorshutdowncanbeusedtodeterminetheinventory.Touseasimplepowerratiotodeterminetheinventoriesoftheisotopeswithhalf-livesgreaterthan1day,thecoreshouldhaveoperatedataconstantpowerforatleast30dayspriortoreactorshutdown.Theassumptionismadethatconstantpowerexistswhenthepowerleveldoesnotvarymorethan+10percentoftheratedpowerlevelfromthetimeaveragedvalue.Fortransientpowerhistorieswhereasteadystatepowerconditionhasnotbeenobtained,apowercorrectionfactorhasbeendevelopedtocalculatethesourceinventoryatthetimeoftheaccident.

TABLE2-1SELECTEDNUCLIDESFORCOREDAMAGEASSESSHENTCoreDamageStateNuclideHalf-Life"PredominantGammasKevYield5*CladFailureFuelOverheatFuelMeltKr-85m"ŽKr-87Kr-88"*Xe-131mXe-133Xe-133m*"Xe-135++I-131I-132I-133I-135Rb-88Cs-134Cs-137Te-129Te-132Sr-89Sr-90"*Ba-140La-140La-142Pr-1444.4h76m2.8h11.8d5.27d2.26d9.14h8.05d2.26h20.3h6.68h17.8m2yr30yr68.7m77.7h52.7d28yr12.8d40.22h92.5m17.27m150(74),305(13)403(84),2570(35)191(35),850(23),2400(35)164(2)81(37)233(14)250(91)364(82)773(89),955(22),1400(14)530(90)1140(37),1280(34),1460(12),1720(19)898(13),1863(21)605(98),796(99)662(85)455(15)230(90)(betaemitter)(betaemitter)537(34)487{40),815(19),1596{96)650(48),1910(9),2410(15),2550(11)695(1.5)*ValuesobtainedfromTableofIsotoes,Lederer,Hollander,andPerlman,SixthEdition.*"Thesenuclidesaremarginalwithrespecttoselectioncriteriaforcandidatenuclides;theyhavebeenincludedonthepossibilitythattheymaybedetectedandthusutilizedinamanneranalogoustothecandidatenuc1ides.

TASLE2-2FUELPELLETINVENTORY~InventorCuriesNuc1ideKr85mKr87Kr88Xe131mXe133Xe133mXe135I131I132I133Rb88Unit13250Mwt0(7)%*3.6(7)5.2(7)5.7{5)1.8(8)2.5(7)3.4(7).8.9(7)1.3(8)1.8(8)1.6(8)5.3(7)Unit23391Mwt2.1(7)3.8(7)5.4(7)6.0(5)1.9(8)2.7(7)3.5(7)9.3(7)1.3{8)1.9(8)1.7(8)5.5(7)Cs134Cs137Te129Te1322.1(7)1.0(7)3.0(7)1.3(8)2.2(7)1.0(7)3.1(7)1.3(8)Sr89Sr90Ba140La140La142Pr1447.2(7)6.6(6)1.5(8)1.6(8)1.4(8)1.1(8)7.5(7)6.8(6)1~6(8)1.7(8)1.4(8)1.1(8)InventorybasedonORIGENrunforequilibrium,end-of-lifecore.*"1.2(7)=1.2x107.Thisnotationisusedthroughoutthisreport.

Thereareafewselectednuclideswithhalf-livesaroundoneyearorlongerwhichinmostinstancesdonotreachequilibriumduringthelifeofthecore.Forthesefewnuclidesaqdwithintheaccuracyofthemethodology,apowercorrectionfactorwhichcomparestheeffectivefullpowerdaysofthecoretothetotalnumberofcalendardaysofcycleoperationofthecoreisapplied.Ouetotheproductioncharacteristicsof,cesium-134,specialconsiderationmustbeusedtodeterminethepowercorrectionfactorforCs-134.ThispowercorrectionfactorcanbeobtainedfromFigure2-1.J2.3.1POWERCORRECTIONFACTORA)Steadystatepowerpriortoshutdown.1)Half-lifeofnuclide<1dayAveraePowerLevelMwtforrior4dasPowerCorrectionFactor=RatedPowerLevel(Mwt)2)Half-lifeofnuclide>1dayAveraePowerLevelMwtforrior30dasPowerCorrectionFactor=RatedPowerLevel(Mwt)3)Halflifeofnuclide=1yearAveraePowerLevelMwtforrior1earPowerCorrectionFactor=RatedPowerLevel(Mwt)Steadystatepowerconditionisassumedwherethepowerdoesnotvarybymorethan+10percentofratedpowerlevelfromtimeaveragedvalue.8)Transientpowerhistoryinwhichthepowerhasnotremainedconstantpriortoreactorshutdown.Forthemajorityoftheselectednuclides,the30-daypowerhistorypriortoshutdownissufficienttocalculateapowercorrectionfactor.

1.00.990KPOWER0.8iERCORRECTIONFACTOR75KPOWER0.60.50.40.30.20.10.02004006008001000CYCLEOPERATION(CALENDAR.DAYS)FIGURE2-1POWERCORRECTIONFACTORFORCS-134BASEDONAVERAGEPOWERDURINGOPERATION PowerCorrectionFactor=where:-X.t-Kit'P(1ej)eEtRP(1-ej)pjRPtjaveragepowerlevel(Nwt)duringoperatingperiodt.jratepowerlevelofthecore(Mwt)operatingperiodindaysatpowerPwherepowerdoesnotvarymorethan+10percentpowerofratedpowerlevelfromtimeaveragedvalue(P)decayconstantofnuclideiininversedays.timebetweenendofperiodjandtimeofreactorshutdownindays.Ifthetotalperiodofoperationisgreaterthanfourhalf-livesofthenuclidebeingconsidered,thepowercorrectionisasfollows.Thisiswithintheaccuracyofthismethodology.gt>4x0.693PowerCorrectionFactor=-kit-'k.t'.EP.(1-ej)eRPForthefewnuclideswithhalf-livesaroundoneyearorlonger,apowercorrectionfactorwhichratioseffectivefullpowerdaystototalcalendardaysofcycleoperationisapplied.EFPOPowerCorrectionFactor=totalcalendardaysofcycleoperationC)ForCs-134Figure2-1isusedtodeterminethepowercorrectionfactor.TouseFigure2-1,theaveragepowerduringtheentireoperatingperiodisrequired.

2.4RELATIONSHIPOFCLAOOAHAGEMITHACTIVITY2.4.1GAPINVENTORYDuringoperation,volatilefissionproductscollectinthegap.Thesefissionproductsareisotopesofthenoblegasesandiodine.(4)Todeterminethefissionproductinventoryofthegap,theANS5.4Standardformulaewereusedwiththeaveragetemperatureandburnupofthefuelrod.Theaveragegapinventoryfortheentirecoreforthismethodologywasestimatedbyassumingthecoreisdividedintothreeregions-alowburnupregion,amiddleburnupregion,andahighburnupregion.UsingtheANS5.4Standard,thegapfractionandsubsequentgapinventorywerecalculatedforeachregion.Eachregionisassumedtorepresentone-thirdofthecore.Thetotalgapinventorywasthencalculatedbysummingthegapinventoryofeachregion.Forthepurposesofthiscoredamageassessmentmethodology,thisgapinventoryisassumedtobeevenlydistributedthroughout.thecore.Table2-3showsthecalculatedgapinventoriesforUnit1andUnit2ofthenoblegasesandiodines.Table2-3-1showstheminimumandmaximumgapinventories.Theminimumandmaximumgapinventoryweredeterminedbyassumingtheentirecorewasoperatingatthelowburnupconditionandthehigh'burnupconditions,respectively.2.4.2SPIKINGPHENOMENAReactorcoolantsystempressure,temperature,andpowertransientsmayresultiniodinespiking.(Cesiumspikingmayalsooccurbutisnotconsideredinthismethodology.)Spikingisnotedbyanincreaseinreactorcoolantiodineconcentrationsduringsometimeperiodafterthetransient.Inmostcases,the'iodineconcentrationwouldreturntonormaloperatingactivityataratebasedon'the'systempurification'hal'f-.life'Spikin'gis'characteristicof-"-".theconditionwhereanincreasein'thenormalprimarycoolantactivityisnotedbutnodamagetothecladdinghasoccurred.10 TABLE2-3GAPINVENTORY~GaInventorCuriesNuclideUnit13250MwtUnit23391HwtKr85m"ŽKr87Kr88"ŽXe131mXe133Xe133m*"Xe135*"3.44(3)3.29(3)7.26(3)8.05(2)1~60{5)1.53(4)8.17(3)3.59(3).3.43(3)7.58(3)8.41{2)1.67(5)1;60(4)8.53(3)I-131I-132I-133I-1352.58(5)4.15(4)1.75(5)8.92(4)2.70(5)4.33(4)1.82(5)9.31(4)Totalcoreinventorybasedon3regionequilibriumcoreatend-of-life.GapinventorybasedonANS5.4Standard.*"Additionalnuclides;nographsprovided.11 TABLE2-,3-1GAPINVENTORYMINIHUMANOHAXIHUMGapInventory,CuriesHinimum-Maximum"*Nuc1ideUnit13250HwtUnit23391HwtKr85m"KI87Kr88*Xe131mXe133Xe133m*Xe135*6.28(2)-8.71(3)6.20(2)-8.39(3)1.29(3)-1',81(4)1.44(2)-2.01(3)3.03(4)-4.10(5)1.16(3)-1.61(4)3.74(3)-5.11(4)6'6(2)-9.09(3)6.47(2)-8.76(3)1.35(3)-1.89(4)1.50(2)-2.10(3)3.16(4)-4.28(5)1.22(3)-1.68(4)3.90(3)-5.33(4)I131I132I133I1354.90(4)-6.69(5)7.78(3)-1.06(5)3.21(4)-4.46(5)1.62(4)-2.27(5)5.12(4)-6.98(5)8.12(3)-1.11(5)3.35(4)-4.66(5)1.69(4)-2.37(5)*Additionalnuclides;nographsprovided.**Minimumvaluesarebasedonthelowburnupregion(5,000HWO/HTU).Haximumvaluesarebasedonthehighburnupregion(25,000HWD/HTU).12 ForthismethodologyconsiderationofthespikingphenomenaintotheradionuclideanalysisislimitedtotheI-131informationfoundinWCAP-9964'.WCAP9964,presentsreleasesinCuriesofI-131duetoa(5)transientwhichresultsinspikingbasedonthenormalprimarycoolantactivityofthenuclides.TheWCAPgivesanaveragereleaseand90percentconfidenceinterval.ThesevaluesarepresentedinTable2-4.'TheuseofthisdataisdemonstratedinSection2.4.3.2.2.4.3ACTIVITYASSOCIATEDWITHCLADDAMAGECladdamageischaracterizedbythereleaseofthefissionproductswhichhaveaccumulatedinthegapduringtheoperationoftheplant.Thecladdingmayruptureduringanaccidentwhenheattransferfromthecladdingtotheprimarycoolanthasbeenhinderedandthecladdingtemperatureincreases.Claddingfailureisanticipatedinthetemperaturerangeof1300to2000'Fdependingupontheconditionsofthefissionproductgasandtheprimarysystempressure.Claddamagecanbegintooccurinregionsofhighfuelrodpeakcladtemperaturebasedontheradialandaxialpowerdistribution.Astheaccidentprogressesandisnotmitigated,otherregionsofthecoreareexpectedtoexperiencehightemperaturesandpossiblycladfailure.Whenthecladdingruptures,itisassumedthatthefissionproductgapinventoryofthedamagedfuelrodsisinstantaneouslyreleasedtotheprimarysystem.Forthismethodologyitisassumedthatthenoblegaseswillescapethroughthebreakoftheprimarysystemboundarytothecontainmentatmosphereandtheiodineswillstayinsolutionandtravelwiththeprimarysystemwaterduringtheaccident.Todetermineanapproximationoftheextentofcladdamage,thetotalactivityofafissionproductreleasediscomparedtothetotalsourceinventoryofthefissionproductatreactorshutdown.Includedinthemeasuredquantityofthetotalactivityreleasedisacontributionfromthenormaloperatingactivityofthenuclide.Anadjustmentshouldbemadetothemeasuredquantityofreleasetoaccountforthenormaloperatingactivity.Directcorrelationscanthenbedevelopedwhichdescribetherelationshipbetweenthepercentageoftotalsourceinventoryreleasedandtheextentofcladdamageforeachnuclide.Figures2-2through2-9presentthedirectcorrelationsforeachnuclideingraphicalform.Thecontributionofthenormaloperatingactivity13 TABLE2-4EXPECTEDIODINESPIKEAveraeCi/mI-131TotalReleaseCuries0.5<SA*<1.00.1<SA<0.50.05<SA<0.10.01<SA<0.050.005<SA<0.010.001<SA<0.005SA<0.0013400380200200100100290/90UerConfidenceLevelCi/m0.5<SA<1.00.1<SA<0.50.05<SA<0.10.01<SA<0.050.005<SA<0.0010.001<SA<0.005SA<0.0016500-95065065030030010*SAisthenormaloperatingI-131specificactivity(yCi/gm)intheprimarycoolant.

0'g0~0.0'F070CJtt$C)~0CY~0OCJc~01007OF00r~0)qadiu9o+00F00.001OOOOhlY)IAhOOOOOOeunnnOCladDamage(';.')FIGURE2-2RELATIONSHIPOF,'4CLADDAMAGEWITHXCOREINVENTORYRELEASEDOFXE-133 1~0'0'0'0'0'F07F05F03~02F01F007005003002<egOpS~001Pu~7~0-4)c5~0-4,e3'"4S2.0-41~0-47~0-550-53'"52'-51'"5IAh~\~~~0~~~~~CVYlillh0OOO00O0O0C4YllAhOCladDamage(/)FIGURE2-3RELATIONSHIPOF/oCLADDAMAGEWITHXCOREINVEilTORYRELEASEDOFI-131 1~0'0'0'0'F1F07F05~03~02aClF007005e.003C~002O~0017'-45'-43'-42'-4rr'br+rgC~gQrrrr1'-4CVWV)OOOOIAhO~OOOOOhlY)VlhOCladDamageP)FIGUREZ-4RELATIONSHIPOF5CLADDAMAGEWITH5COREINVENTORYRELEASEDQFI-131WITHSPIKING 0~~0~01F00F00F00.000017~0-o50-Oc3~0-Cl2'"dJ51~0-7'"5'"gQrroqr3~0-1'"AlN"IAW~~~CVP)llewhOO0000Q00QCV~U1WClCladDamage(i.)FIGURE2-5RELATIONSHIPOF/CLADDAMAGEMITH~~COREINVENTORYRELEASEDOFKR-87 0'0~0~F107Ie0(YO~0~).0o~01F00?qOr.'>%rrgurquu9ioF00F00~001CV&Ill~~~~CVY)IAbddddddddddCVnv)n.dCladDamage(5)FIGURE2-6RELATIONSHIPOF5CLADDAMAGEWITH5COREINVENTORYRELEASEDOFXE-131M19 0~~0~00F01F00F00F00F00.OOIcr.7~0-5.0-4O+JQJ3'-~2'-4QQ+rd~Q~OrrS1~0"4Oj~0-5~0-3~0-2~0-1~0-CVMIAh~\~~\~IAh0O,OQOCladDamage(X)OC)00OOl.)tAhQFIGUREP-7RELATIONSHIPOFXCLADDAt1AGEWITHX,COREINVENTORYRELEASEDOFI-13220 1~0~0~0~0~0'~0~0~0~0~01~00F00F00OF000017~0-OS3'"~2'"~8~gQrgo+~gQj<~rr1~0"47~0-5~0-3'"2~0-1~0-OM7W~~~VlWOOOOO0OOOOOIAhOCladDamage(X)FIGURE2-8RELATIONSHIPOF'XCLADDAMAGEWITHgCOREINVENTORYRELEASEDOFI-133 10~0~0~0.F1~0~0~0~0.01F00F00F00F00pS~001m7~0-5'4Cl3.0-do2.0-40~Qrgor(O~rQr~o+I~0-47~0"5'"2'"1'"Al~~~~~~~~hlYlthh0O00000O0OCVY)V)hOCladDamage('A)FIGURE2-9RELATIONSHIPOF,oCLADDAMAGE.WITHNCOREINVENTORYRELEASEDOFI-135 hasbeenfactoredintothecorrelationsshowninFigures2-2through2-9.ExamplesofhowtoconstructthecorrelationsshowninFigures2-2through2-4arepresentedinthenext,twosections.Figures2-5through2-9weredeterminedinthesamefashionasdescribedintheexamples.ItshouldbenotedthatnotallofthefissionproductslistedinTable2-3needtobeanalyzedbutasmanyaspossibleshouldbeanalyzedtodetermineareasonableapproximationofcladdamage.2.4.3.1Xe-133AgraphicalrepresentationcanbedevelopedwhichdescribesthelinearrelationshipofthemeasuredreleasepercentageofXe-133totheextentofcladdamage.Sincethelinearrelationshipisbasedonpercentageofinventoryreleased,thelinearrelationshipappliestoallMestinghousestandardplants.TheWestinghouse3-Loopplantisusedasthebaseplantfordevelopingtherelation.ThetotalsourceinpentoryofXe-133ForaWestinghouse3-Loopplantis1.6x10Curies[j.For100percentclad8.(13)ldamageallofthegapinventory,whichcorrespondsto1.43x105Curie]wouldbereleased.For0.1percentcladdamage,1.43x10(13)12Curieswouldbereleased.Thesetwovaluescanbeusedtorepresenttwopointsofthelinearrelationshipbetweenpercentageoftotalinventoryreleasedandtheextentofcladdamage.However,thenormaloperatingactivityneedstobeaccountedintotherelation.FromTable2-5thenormaloperatingactivityofXe-133is18pCi/gm.Theaverageprimarycoolant(6)massofa3-Loopplantis1.78x10grams.Thetotalnormaloperating8contributiontothetotalreleaseofXe-133is3200Curies.Thustheadjustedreleasesare3340Curiesand1.46x10Curiesfor0.1percentcladdamage5-3and100percentcladdamage,respectively.Thiscorrespondsto2.2x10-2percentfor0.1percentcladdamageand9.1x10for100percentcladdamage.This'elationisshowninFigure2-2.Figure2-2alsoshowsaminimumandamaximumrelationwhichboundthebestestimateline.Theminimumandmaximumlinesweredeterminedbyboundingthefissionproductgapinventory.TheminimumgapinventorywasdeterminedbyassumingtheentirecorewasoperatingatthelowburnupconditionusedtocalculatetheaveragegapinventoryasdescribedinSection2.4.1.The23 TABLE2-5NORMALOPERATINGACTIVITY~NuclideSpecificActivityinReactorCoolant'i/mKr85mKr87Kr88Xe131mXe133Xe133mXe135I131I132I133I,1351.1(-1)6.0(-2)2.0(-1)1.1(-1)1.8(+1)2.2(-1)3.5(-1)2.7(-1)1.0(-1)3.8(-1)1.9(-1)ValuesobtainedfromANS18.124 maximumgapinventorywasdeterminedbyassumingtheentirecorewasoperatingatthehighburnupconditionofSection2.4.1.Forthe3-Loopplant,theminimumgapinventoryforeXe-133is2.71x10Ci,andthemaximumvalueis3.67x10Ci'.Thenormaloperatingactivityisboundedbyassuminga5(13)watermassof1.23x10grams(2-Loopplant)fortheminimumvalueand2.68x10grams(4-Loopplant)Forthemaximumv'alue.Thepointsoftheminimumandmaximumlinearrelationsarecalculatedinthesamemannerasdiscussedabove.2.4.3.2I-131ThegainventoryforaWestinghouse3-LoopplantforI-131is2.3lxl05Curie'j.Theminimumandmaximumgapinventoryfora3-Loopplantfor(13)lI-131is4.38xl0Ciand5.98xl0Ci,respectivelyj.Thesource45lil3)l~(13)linventoryofI-131fora3-Loopplantis8.0x10Curiesg.ThenormaloperatingspecificactivityforI-131fromTable2-5is0.27yCi/gm.Withaprimary.coolantmassof1.78x10gmforastandard3-Loopplant,the8normaloperatingactivityofI-131is48Curies.Thepointsoftheaverage,minimum,andmaximumrelationsarecalculatedinthesamemannerasdescribedinSection2.4.3.1.Figure2-3showsthepercentageofI-131activityasafunctionofcladdamage.ThepercentagereleaseofI-131calculatedfromtheradionuclideanalysiswouldbecomparedtoFigure2-3toestimatetheextentofcladdamage.ForI-131,thepossibilityofiodinespikingshouldbeconsideredwhendistinguishingbetweennocladdamageandminorcladdamage.ThecontributionofiodinespikingisdiscussedinSection2.4.2andisestimatedtobeasmuchas950CuriesofI-131releasedtoprimarysystemwithanaveragereleaseof350CuriesbasedonanormaloperatingI-131activityof0.27yCipergram'.ThelinearrelationshipsofFigure2-3areadjustedtoaccountfor(6)thereleaseduetoiodinespikingbyadding950'CuriesofI-131tothemaximumreleaseandbyadding350CuriesofI-131totheminimumandaveragerelease.Figure2-4showsthepercentageofI-131releasedwithiodinespikingversuscladdamage.Iodinespikingwasnotconsideredduringthecalculationsofthecorrelationsfortheremainingiodines,I-132,I-133,andI-135,Figures2-7through2-9,respectively.25 2.4.4GAPACTIVITYRATIOSOnceequilibriumconditipnsarereachedforthenuclidesduringoperation,afixedinventoryofthenuclidesexistswithinthefuelrod.Forthesenuclideswhichreachequilibrium,theirrelativeratioswithinthefuelpelletcanbeconsideredaconstant.Equilibriumconditionscanalsobeconsideredtoexistinthefuelrodgap.Underthisconditionthegapinventoryofthenuclidesisfixed.Thedistributionofthenuclidesinthegaparenotinthesameproportionasthefuelpelletinventorysincethemigrationofeachnuclideintothegapisdependentonitsparticulardiffusionrate.Sincetherelativediffusionratesofthesenuclidesundervariousoperatingconditionsareapproximatelyconstant,therelativeratiosofthenuclidesinthegapareknown.Inthepresenceofotherindicatorsofamajorrelease,therelativeratiosofthenuclidescanbecomparedwiththerelativeratiosofthenuclidesanalyzed(correctedtoshutdown)duringanaccidenttodeterminethesourceofthefissionproductrelease.Table2-6presentstherelativeactivityratiosforboththefuelpelletandthegap.Therelativeratiosforgapactivitiesaresignificantlylowerthanthefuelpelletactivityratios.Measuredrelativeratiosgreaterthangapactivityratiosareindicativeofmoreseverefailures,e.g.,fueloverheat.2.4.5ADJUSTMENTSTODETERMINEACTIVITYRELEASEDWhenanalyzingasampleforthepresenceofnuclides,theisotopicconcentrationofthesamplemediumisexpressedasthespecificactivityofthesampleineitherCuriespergramofliquidorCuriespercubiccentimeterofatmosphere.Thespecificactivityofthesampleshouldthenbeadjustedtodeterminethetotalactivityofthatmedium.Themeasuredactivityofthesampleneedstobeadjustedtoaccountforthedecayfromthetimethesamplewasanalyzedtothetimeofreactorshutdownandadjustedtoaccountforpressureandtemperaturedifferenceofthesamplerelativetotemperatureand26 RTABLE2-6ISOTOPICrACTIVITYRATIOSOFFUELPELLETANDGAPNuclideFuelPelletActivitRatioGaActivitRatioKr-85mKr-87Kr-88Xe-131mXe-133Xe-133mXe-1350.110.220.290.0041.00.140.190.0220.0220.0450.0041.00.0960.051I-131I-132I-133I-1351.01.52.11.91.00.170.710.39NobleGasIsotoeInventorXe-133InventoryIodineRatiIodineIsotoeInventorI-131Inventory"Themeasuredratiosofvariousnuclidesfoundinreactorcoolantduringnormaloperationisafunctionoftheamountof"tramp"uraniumonfuelrodcladding,thenumberandsizeof"defects"(i.e."pinholes"),andthelocationofthefuelrodscontainingthedefectsinthecore.Theratiosderivedinthisreportarebasedoncalculatedvaluesofrelativeconcentrationsinthefuelorinthegap.Theuseofthesepresentratiosforpostaccidentdamageassessmentisrestrictedtoanattempttodifferentiatebetweenfuelovertemperatureconditionsandfuelcladdingfailureconditions.Thustheratiosderivedherearenotrelatedtofueldefectlevelsincurredduringnormaloperation.27 pressureconditionsofthemedium.Alsothemass(liquid)orvolume(gas)ofthesamplemediumisrequiredtocalculatetheisotopicactivityofthatmedium.Thefollowingsyctionsdiscusstherequiredadjustments.2.4.5.lDILUTIONOFSAMPLEMEDIUMThedistributionofthetotalwaterinventoryshouldbeknowntodeterminethewateramountthatisassociatedwitheachsamplemedium.Ifasampleistakenfromtheprimarysystem,anapproximationoftheamountofwaterintheprimarysystemisneededandasimilarapproximationisrequiredforasumpsample.Forthepurposesofthismethodologythewaterisassumedtobedistributedwithintheprimarysystemandthesump.However,considerationshouldbetakenifasignificantprimarysystemtosecondarysystemleak'rateisnotedasinthecaseofasteamgeneratortuberupture.TheamountofwaterthatisavailablefordistributionistheinitialamountofprimarysystemwaterandtheamountofwaterthathasbeendischargedfromtheRefuelingWaterStorageTank(RWST).Also,anadjustmentmustbemadeforwateraddedviathecontainmentspraysystems,accumulators,chemicaladditiontanks,andicecondensers.Toapproximatethedistributionofwater,themonitoringsystemsofthereactorvessel,pressurizer,sump,andRWSTcanbeemployed.Ifnotallofthemonitoringsystemsareavailable,themonitoringsystemswhichareworkingcanbeusedbyassumingthatthetotalwaterinventoryisdistributedinthesumpandtheprimarysystemwithconsiderationgivenifasignificantprimarysystemtosecondarysystemleakrateisnoted.Theapproximatetotalactivityoftheliquidsamplescanthenbecalculated.iTheD.C.CookUnitlandUnit2containmentsareeachequippedwithice6condensers.Eachcontainmenthousesapproximately2.7x10poundsofice,whichprovidesanadditionalsourceofwater.TheRWSTcanprovideuptoapproximately350,000gallonsofemergencycorecoolingwaterduringanaccident.The4accumulatorsareeachequippedtoprovideapproximately950ftofwater.Theboronln]ectiontankcansupplyg00gallonsofwater.I3RCSactivity(Curies)=SpecificActivity(Ci/ccorCi/gm)xRCSwatervolumeormass(ccorgm).28 Sumpactivity(Curies)=SpecificActivity(Ci/ccorCi/gm)xSumpwatervolumeormass(ccorgm).rTotalwateractivity=RCSactivity+Sumpactivity+ActivityleakedtoSecondarySystem+Activitiesfromothersources(accumulators,icecondensers,sprayadditivetanks,etc.).Note:Thespecificactivitiesshouldbedecaycorrectedtoreactorshutdown,andtheRCSamountshouldbecorrectedtoaccountfortemperatureandpressuredifferencesbetweensampleandRGBThecontainmentatmosphereactivitycanthenbeaddedtoapproximatethetotalactivityreleasedattimeofaccident.TotalActivityReleased=TotalMaterActivity+ContainmentAtmosphereActivity2.4.5.2PRESSUREANDTEMPERATUREADJUSTMENTThemeasurementsforthecontainmentatmospheresamplesneedtobeadjustedifthepressureandtemperatureofthesamplesatthetimeofanalysisaredifferentthantheconditionsofcontainmentatmosphere.Theadjustmentstothespecificactivityandthecontainmentvolumeareasfollows.P2Tl+460SpecificActivity(Atmosphere)=SpecificActivity(Sample)x-x(460)'1'2+where:Tl'lT2,P2measuredsampletemperature('F)andpressure(psia)containmentatmospheretemperature('F)andpressure(psia).PT+460CorrectedContainmentVolume=ContainmentFreeVolume(SCF)xp(T+460)'2'3' where:T2,P2T3,P3containmentatmospheretemperature('F)andpressure(psia)standardtemperature(32'F)andpressure(14.7psia).tTheaboveadjustmentsarebasedonmolarvolumes.Forsamples'inwhichtheatmospheresampleisdrawnintoaspecifiedvolumeandtheanalysisisperformedtothisvolume,noadjustmentstoeitherthesamplespecificactivityorcontainmentvolumearerequired.Forthoseplantswit6icecondensers,considerationshouldbegiventoaccountforadecreaseinfreevolumeduetotheicemeltingoccupyingaportionofthecontainmentvolume.iEventhoughD.C.Cookisaplantwithicecondensers,noadjustmentisneededtothecontainmentfreevolumeduetotheeffectoftheicemelting.Thelistedcontainmentfreevolume(1.2x10ft)takesintoaccountthe63presenceofsolidice.Sincethereisnegligibledifferencebetweenthedensitiesoficeandwater,noadjustmentisrequired.jThetotalactivityreleasedtothecontainmentatmosphereisTotalContainmentActivity=SpecificActivity(Atmosphere)xCorrectedContainmentVolumewherethespecificactivity(atmosphere)hasbeendecaycorrectedtotimeofreactorshutdown.Thespecificactivityoftheliquidsamplesrequiresnoadjustmentifthespecificactivityisreportedonaper-grambasis(pCi/gm).Ifthespecificactivityisreportedonaper-volumebasis(pCi/cc),anadjustmentisperformedtoconverttheper-volumespecificactivitytoaper-gramspecificactivity.Theconversionisperformedforconsistencywithlatercalculations.Ifthetemperatureofthesampleisabove200'F,anadjustmentisrequiredtotheconversion.Inmostcasesthesampletemperaturewillbe30

below200'Fandnoadjustmentisnecessary.Figure2-10showsarelationofwaterdensityatsometemperaturerelativetothewaterdensityatstandardtemperatureandpressure.Themassoftheliquidmedium(RCSorsump)canbecalculatedfromthevolumeofthemedium.Ifthemedium(RCSorsump)temperatureattimeofsampleisabove200'F,anadjustmentisrequiredtotheconversion.A.RCSorSumptemperature>200'FRCSorsumpmass(gm)=RCSorSumpVolume(ft)328.3x10cc3x(2)xpxpSTp'TPft3where:~(2)=waterdensityratioatmedium(RCSorsump)temperature,PSTPFigure2-10=waterdensityatSTP=1.00gm/cc.STPB.RCSorsumptemperature<200FRCSorSumpHass(gm)=RCSofSumpVolume(ft)xpSTPx328.3x10cc3ftwhere:pwaterdensityatSTP=1.00gm/cc.ThetotalactivityoftheRCSorsumpisasfollows.RCSorSumpActivityRCSorSumpSpecificActivity(yCi/gm)xRCSorSumpHass(gm)wherethespecificactivityhasbeendecaycorrectedtotimeofshutdown.31 600'00'400CPlQQJ300QJi-200ipp.0~~/pSTPFIGURE2-10WATERDEi'ISITYRATIO(TEMPERATUREVS.STP)32 tThesumpandcontainmentwatervolumecanbeapproximatedfromFigures2-10Aand2-10Bbasedonthereadingsofthewaterlevelindicatorsofthesumpandcontainment.Thereactorvessellevel.indicationsystemcanbeusedtoapproximatetheRCSvolume,asdescribedbythefollowing.'.Ifthewaterlevelinthereactorvesselindicatesthe,systemisfull,thenthefullreactorcoolantsystemwatervolumeisused.For.Unit1andUnit2theRCSvolumeofeachisapproximatelyll,780ftat570'Fand2250psia.2.Ifthewaterlevelinthereactorvesselisbelowthelowendcapabilityoftheindicator,theRCSvolumeisunknown.Inthiscase,thesumpsampleshouldbegiven.primaryconcern.3.Ifthereactorvessellevelindicationsystemisnotworking,then,byknowingthewatersourcesavailable,theothermonitorscanbeusedtoestimatetheRCSvolume.Ifitisknownhowmuchwaterisavailable(volumesofRWST,accumulators,boroninjectiontank,andoriginalRCSvolume),thevolumeofthesumpandcontainmentwaterissubstractedfromtheavailablewatervolumetoestimatetheRCSvolume.Alsotobeconsideredasasourceofwateriswaterfromthemeltingice.Anassumptioncanbemadethatalltheicemeltsinapproximately3.to5hoursafterthestartofanaccident.2.4.5.3DECAYCORRECTIONThespecificactivityofasampleisdecayadjustedtotimeofreactorshutdownusingthefollowingequation.SecificactivitmeasuredSpecificactivityatshutdown=tfwhere:radioactivedecayconstant,.l/sectimeperiodfromreactorshutdowntotimeofsampleanalysis,sec.33

'i00.70'O~C5Ul50~ICDQgp30'0'O...VOLUME.FT3FIGURE2-10ASUMPWATERVOLUMEVERSUSSUMPLEVELINDICATION34 90..80.70'0'DhJ50~C)ICCDClz~0~30'0'0~C)C)ClC)oOOVOLUMEFTClC)C)C)C)C)OoOFIGURE2-108CONTAINMENTWATERVOLUMEVERSUSCONTAINMENTLEVELINDICATION35 Sincethiscorrectionmayalsobeperformedbysomeanalyticalequipment,caremustbetakentoavoidduplicatecorrection.Also,considerationmustbegiventoaccountforprecursoreffectduringthedecayofthenuclide.forthismethodology,onlytheparent-daughterrelationshipsareconsidered.Table2-7liststhesignificantparent-daughterrelationshipsassociatedwiththemethodology.Thedecayschemeoftheparent-daughterrelationshipisdescribedbythefollowingequation.-XAt-XBt-XBt~BX-X~A~BBAwhere:0~Aactivity(Ci)orspecificactivity(yCi/gmorpCi/cc)oftheparentatshutdownqoBactivity{Ci)orspecificactivity{pCi/gmorpCi/cc)ofthedaughteratshutdownactivity(Ci)orspecificactivity(yCi/gmorpCi/cc)ofthedaughterattimeofsample-1decayconstantoftheparent,sec-1decayconstantofthedaughter,sectimeperiodfromreactorshutdowntotimeofsampleanalysis,sec.Sincetheactivityofthedaughteratsampletimeisduetothedecayoftheparentandthedecayofthedaughterinitiallyreleasedatshutdown,anestimationofthefractionofthemeasuredactivityatsampletimeduetoonlythedecayofdaughterisrequired.Tousetheaboveequationtodeterminethisfraction,anassumptionismadethatthepercentagesofthesourceinventoriesoftheparentandthedaughterreleasedattimeofshutdownare36 TABLE2-7PARENT-OAUGHTERRELATIONSHIPSrParentParentHalfLife~~DaahterOaughterHalfLifeŽKr-882.8,hRb-8817.8m1.00I-1318.05dXe-131m11.8d.008I-133I-133Xe-133m20.3h20.3h'2.26dXe-133mXe-133Xe-1332.26d5.27d5.27d.024.9761.00I-135Xe-135mI-1356.68h15.6m6.68hXe-135Xe-135Xe-135m9.14h9.14h15.6m.701.00.30Te-13277.7hI-1322.26h1.00Sb-129Te-,129mSb-1294.3h34.1d4.3hTe-129Te-129Te-129m68.7m68.7m34.1d.827.680.173Ba-14012.8dLa-14040.22h1.00Ba-14211mLa-14292.5m1.00Ce-144284dPr-14417.27m1.00"TableofIsotoes,Lederer,Hollander,andPerlman,SixthEdition""BranchingdecayFactor37 equal(forthenuclidesusedherewithinaFactorof2).Thefollowingstepsshouldbefollowedtocalculatethefractionofthemeasuredactivityduetothedecayofthedaughterthatwasreleasedandthentocalculatetheactivityofthedaughterreleasedatshutdown.1.Calculatethehypotheticaldaughterconcentration(9)atthetimeofthesampleanalysisassuming100percentreleaseoftheparentanddaughtersourceinventory.-%At-XBt-Xte-e)+~Bewhere:0')A100%sourceinventory(Ci)ofparent,Table2-2or2-8qo8100Ksourceinventory(Ci)ofdaughter,Table2-2or2-8()8(t)hypotheticaldaughteractivity(Ci)atsampletimeifparenthas2daughters,Kisthebranchingfactor,Table2-7'A-1parentdecayconstant,sec-1daughterdecayconstant,sectimeperiodfromshutdowntotimeofsample,sec.2.OeterminethecontributionofonlythedecayoftheinitialinventoryofthedaughtertothehypotheticaldaughteractivityatsampletimeqokBtQB(t)38 TABLE2-8SOURCEINVENTORYOFRELATEDPARENTNUCLIDESNuclideUnit13250HWtUnit23391HWtXe-135mSb-129Te-129mBa-142Ce-1443.8(7)2.9(7)7.3(6)1.5(8)1.0(8)4.0(7)3.0(7)7.6(6)1.5(8)1.0(8)39 3.Calculatetheamountofthemeasuredsamplespecificactivityassociatedwiththedecayofthedaughterthatwasreleased.M=Frxmeasuredspecificactivity(yCi/gmorpCi/cc)B4.Decaycorrectthespecificactivity(M)toreactorshutdown.MMB-XteB2.5RELATIONSHIPOFFISSIONPROOUCTRELEASEWITHOVERTEMPERATURECONDITIONSThecurrentconceptofthemechanismsforfissionproductreleasefromU02fuelunderaccidentconditionshasbeensummarizedin2documents,draftNUREG-0956andIOCORTask11.1('.Thesedocumentsdescribefive(8)principalreleasemechanisms;burstrelease,.diffusionalreleaseofthepellet-to-claddinggapinventory,grainboundaryrelease,diffusionfromtheUOgrains,andreleasefrommoltenmaterial.Thereleasewhichoccurswhen2thecladdingfails,i.e.,gaprelease,isutilizedtoquantifytheextentofcladfailureasdiscussedinSection2.4.Table2-9presentstheexpectedfueldamagestateassociatedwithfueTrodtemperatures.Fissionproductreleaseassociatedwithovertemperaturefuelconditionsarisesinitiallyfromthatportionofthenoblegas,cesiumandiodineinventoriesthatwaspreviouslyaccumulatedingrainboundaries.Forhighburnuprods,itisestimatedthatapproximately20percentoftheinitialfuelrodinventoryofnoblegases,cesium,andhalogenswouldbereleased.Releasefromlowerburnupfuelwouldnodoubtbeless.Followingthegrainboundaryrelease,additionaldiffusionalreleasefromU02grainsoccurs.Estimatesofthetotalrelease,includingUOdiffusionalrelease,varyfrom20to40percent2ofthenoblegas,iodineandcesiuminventories.Additionalinformationonthereleaseoffissionproductsduring(9)overtemperatureconditionswasobtainedfromtheTMIaccident.Inthisinstancecurrentopinionisthatalthoughthecorehadbeenoverheated,fuelmelthadnotoccurred.ValuesofcoreinventoryfractionofvariousfissionproductsreleasedduringtheaccidentaregiveninTable2-10.Thesevalues,40 TABLE2-9EXPECTEDFUELDAMAGECORRELATIONWITHFUELRODTEMPERATURE(B)FuelDamaeNoDamage<1300CladDamageBallooningofzircaloycladdingBurstofzircaloycladdingOxidationofcladdingandhydrogengeneration1300-2000>13001300-2000>1600FuelOvertemperatureFissionproductfuellatticemobilityGrainboundarydiffusionreleaseoffissionproducts2000-34502000-25502450-3450FuelMeltDissolutionandliquefactionofUOintheZircaloy-ZrOeutectic2MeltingofremainingUO2>3450>34505100Thesetemperaturesarematerialpropertycharacteristicsandarenon-specificwithrespecttolocationswithinthefueland/orfuelcladding.

TABLE2-10PERCENTACTIVITYRELEASEFOR100PERCENTOVERTEHPERATURECONOITIONSNuclideMin.*Max.ŽNominal**Hin."*"Hax.***Kr-854070Xe-133426652.4070I-1314155Cs-1374560Sr-900.08*++*Ba-1400.10.20.150.080.2*ReleasevaluesbasedonTHI-2measurements.*"NominalvalueissimpleaverageofallKr,Xe,I,andCsmeasurements.**+,HinimumandmaximumvaluesofallKr,Xe,IandCsmeasurements.~""*Onlyvalueavailable.42 derivedfromradiochemicalanalysisofprimarycoolant,sump,andcontainmentgassamples,providemuchgreaterreleasesofthenoblegases,halides,andcesiums,thanisexpected,tobereleasedsolelyfromcladdingfailures.Inaddition,smallamountsofthemorerefractoryelements,barium-lanthanum,andstrontiumwerereleased.IntheparticularcaseofTMI,thereleasemechanism,inadditiontodiffusionalreleasefromgrainboundariesandU02grains,isbelievedtoarisefromU02graingrowthinsteam.TherelationshipbetweenextentoffueldamageandfissionproductreleaseforseveralradioisotopesduringovertemperatureconditionisdepictedgraphicallyinFigures2-11and2-12.Toconstructthefigures,theextentoffueldamage,expressedasapercentageofthecore,isplottedasalinearfunctionofthepercentageofthesourceinventoryreleasedforvariousnuclides.ThevaluesusedinconstructingthegraphswereobtainedfromTable2-10.Forexample,if100percentofthecoreexperiencedovertemperatures,52percentofXe-133coreinventorywouldbereleased.If1percentofthecoreexperiencedovertemperature,0:52percentofXe-133coreinventorywouldbereleased.Theassumptionisalsomadethatnuclidesofanyelement,e.g.,I-131andI-133,havethesamemagnitudeofrelease.Inordertoapplythesefigurestoaparticularplant,power,decay,anddilutioncorrectionsdescribedearlierinthisreportmustbeappliedtotheconcentrationsofnuclidesdeterminedfromanalysisofradionuclidesamples.Themaximumandminimumestimatesof.releasepercentagesarethosegiveninTable2-10astherangeofvalues:nominalvaluesofreleasearesimpleaveragesofthemiminumandmaximumvalues.2.6RELATIONSHIPOFNUCLIDERELEASEWITHCOREMELTCONDITIONSFuelpelletmeltingleadstorapidreleaseofmanynoblegases,halides,andcesiumsremaininginthefuelafteroverheatconditions.Significantreleaseofthestrontium,barium-lanthanumchemicalgroupsisperhapsthemostdistinguishingfeatureofmeltreleaseconditions.Valuesofthereleaseoffissionproductsduringfuelmeltconditionsarederivedfromex-pileexperimentsperformedbyvariousinvestigators.

70.50'0'0'o~5C$Cl3~r~Qr2~OCJ)SO0~70~0~0~0IAh..OOOF7OOOV)KOFuelOvertemperature(5)FIGURE2-1lRELATIONSHIPOFXFUELOYERTEMPERATUREWITHXCOREINYENTORYRELEASEDOFXE,KR,I,ORCS 1~0~0.0.0~F1~0~0~0F01CCF00F00F00F00.@grqz+rrqO+F0017'"5'"3~0-2~0-1'"oCV0OC)FuejOvertemperature(A)FIGUREZ-l2RELATIONSHIPOF'AFUELOVERTEMPERATUREWITHXCOREINVENTORYRELEASEDOFBAORSR Thesereleasemeasurementshavebeenexpressedasreleaseratecoefficientsforvarioustemperatureregimes.ThesereleaseratecoefficientshavebeenrepresentedbyasimpleexponentialequationindraftNUREG-0956.Thisequationhastheform:K(T)K(T)AewherereleaseratecoefficientA&8=constantstemperature.ThesereleaseratecoefficientswereutilizedwithcoretemperatureprofilestodevelopfissionproductreleaseestimatesforvariousaccidentsequencesforwhichcoremeltispostulatedindraftNUREG-0956.Fissionproductreleasepercentagesforthreeaccidentsequenceswhichleadto100percentcoremeltaregiveninTable2-11.Thexenon,krypton,cesium,iodine,andtellurium'elementshavebeenarrangedintoasinglegroupbecauseofsimilarityintheexpectedmagnitudeofovertemperaturerelease.Theassumptionisalsomadethatnuclidesofanyelemente.g.,Iodine131andIodine133,havethesamemagnitudeofrelease.Thedifferencesinthecalculatedreleasesofthevariouselementsforthedifferentaccidentsequenceswereusedtodetermineminimumandmaximumvaluesofexpectedrelease;nominalvaluesofreleasearesimpleaveragesofallreleasevalueswithinagroup.ThepercentagereleaseofvariousnuclideshasbeencorrelatedtopercentageofcoremeltwiththelinearextrapolationsshowninFigures2-13through2-15.2.7SAMPLINGLOCATIONSAsurveyofanumberofMestinghouseplantshasindicatedthatthepostaccidentsamplingsystemlocationsforliquidandgaseoussamplesvariesforeachplant.Toobtainthemostaccurateassessmentofcoredamage,itisrecommendedtosampleandanalyzeradionuclidesfromthereactorcoolantsystem,thecontainmentatmosphere,andthecontainmentsump(ifavailable).Othersamplescanbetakendependentontheplant'scapabilities.The TABLE2-11PERCENTACTIVITYRELEASEFOR100PERCENTCOREMELTCONOITIONSLarge*Small"~SeciesLOCATransient*LOCANominal*"Min."*"ReleaseReleaseax.***Release88.3599.4578.38Kr88.3599.4578.3887709988.2399.4478.09Cs88.5599.4678.84Te78.5294.8810.4428.1771.0414.801044Ba19.6643.8724.08Pr0.822.361.021.40.82.4*Calculatedreleasesforsevereaccidentscenarioswithoutemergencysafeguardfeatures,takenfromdraftNUREG-0956**NominalreleaseareaveragesofXe,Kr,I,Cs,andTegroups,orSrandBagroups.***Maximumandminimumreleasesrepresentextremesofthegroups.

100.70.SO~30~20'OroryPp0~70~0~0~0'IAhOOhlOOOOVlhOFuelMelt(%%d)FIGURE213RELATIONSHIPOF%%dFUELMELTWITH%%doCOREINVENTORYRELEASEOOFXE,KR,I,CS,ORTE 100.010.00.10.011.010.0FuelMelt(A)100.0FIGURE2-14RELATIONSHIPOF%FUELMELTWITH/oCOREINVENTORYRELEASEDOFBAORSR 100.010.01.00.10.010.0011.010.0FuelMelt(1)100.0FIGURE2-15RELATIONSHIPOF%%uFUELMELTWITHXCOREINVENTORYRELEASEDOFPR50 specificsamplelocationstobeusedduringtheinitialphasesofanaccidentshouldbeselectedbasedonthetypeofaccidentinprogress.Ifthetypeofaccidentscenarioisunknown,knownplantparameters(pressure,temperature,levelindications,etc.)canbeusedasabasistodeterminetheprimesamplelocations.Considerationshouldbegiventosamplingsecondarysystemifasignificantleakfromtheprimarysystemtosecondarysystemisnoted.Table2-12presentsalistofthesuggestedsamplelocationsfordifferentaccidentscenariosbasedontheusefulnessoftheinformationderivablefromthesample.t0.C.Cook'sPASSisequippedtoobtainsamplesfromhotloop1and3,eastandwestRHR,containmentsump,pressurizersteamspaceandcontainmentair.Plantpersonnelwi11useTable2-12asaguideindeterminingsamplelocations,butfinaldiscretionisleftuptotheplantpersonnel.51

,SuestedSamlinLocationsScenarioPrincipalSamlinLocationsOtherSamlinLocationsSmallBreakLOCAReactorPower>lg"ReactorPower<lg"RCSHotLeg,ContainmentAtmosphereRCSHotLegRCSPressurizerRCSPressurizerLargeBreakLOCAReactorPower>15*ReactorPower<15"SteamLineBreakContainmentSump,ContainmentAtmosphere,RCSHotLeg'ontainmentSump,ContainmentAtmosphereRCSHotLeg,RCSPressurizerContainmentAtmosphereSteamGeneratorTubeRuptureIndicationofSignifi-cantContainmentSumpInventoryRCSHotLeg,SecondarySystemContainmentSump,ContainmentAtmosphereContainmentAtmosphereContainmentBuildingRadiationMonitorAlarmSafetyInjectionActuatedContainmentAtmosphere,ContainmentSumpRCSHotLegRCSPressurizerIndicationofHighRadiationLevelinRCSRCSHotLegRCSPressurizerAssumeoperatingatthatlevelforsomeappreciabletime.

3.0AUXILIARYINOICATORSThereareplantindicatorsmonitoredduringanaccidentwhichbythemselvescannotprovideausefulestimatebutcanprovideverificationoftheinitialestimateofcoredamagebasedontheradionuclideanalysis.Theseplantindicatorsincludecontainmenthydrogenconcentration,coreexitthermocoupletemperatures,reactorvesselwaterlevel,andcontainmentradiationlevel.Whenprovidinganestimateforcoredamage,theseplantindicators,ifavailable,shouldconfirmtheresultsoftheradionuclideanalysis.Forexample,ifthe,coreexitthermocouplereadingsandreactorvesselwaterlevelindicateapossibilityofcladdamageandtheradionuclideconcentrationsindicatenocladdamage,thenarecheckofbothindicationsmaybeperformedorcertainindicationsmaybediscountedbasedonengineeringjudgment.3.1CONTAINMENTHYOROGENCONCENTRATIONAnaccident,inwhich'thecoreisuncoveredandthefuelrodsareexposedtosteam,mayresultinthereactionofthezirconiumofthecladdingwiththesteamwhichproduceshydrogen.ThehydrogenproductioncharacteristicofthezirconiumwaterreactionisthatForeverymoleofzirconiumthatreactswithwater,twomolesofhydrogenareproduced.Forthismethodologyitisassumedthatallofthehydrogenthatisproducedisreleasedtothecontainmentatmosphere.Thehydrogendissolvedintheprimarysystemduringnormaloperationisconsideredtocontributeaninsignificantamountofthetotalhydrogenreleasedtothecontainment.ForUnit1andUnit2,thereleaseofthedissolvedhydrogenandthehydrogeninthepressurizergasspacetothecontainmentcorrespondstoacontainmenthydrogenconcentrationofO.lpercentbyvolume,whichcanbeconsideredinsignificantwithintheaccuracyofthisreport.Intheabsenceofhydrogencontrolmeasures,monitoringthiscontainmenthydrogenconcentrationduringtheaccidentcanprovideanindicationoftheextentofzirconiumwaterreaction.Thepercentageofzirconiumwaterreactiondoesnotequalthepercentageofcladdamagedbutitdoesprovideaqualitativeverificati'onoftheextentofcladdamageestimatedfromtheradionuclideanalysis.53 Figure3-1showstherelationshipbetweenthehydrogenconcentrationandtheperce'ntageofzirconiumwaterreactionforUnit1andUnit2.TherelationshipshowninFig'ure3-1doesnotaccountforanyhydrogendepletionduetohydrogenrecombinersandhydrogenignitions.TherecombinersthatnowexistarecapableofdealingeffectivelywiththerelativelysmallamountsofhydrogenthatresultfromradiolysisandcorrosionfollowingadesignbasisLOCA.However,theyareincapableofhandlingthehydrogenproducedinanextensivezirconium-steamreactionsuchaswouldresultfromseverecoredegradation.Currentrecombinerscanprocessgasthatisapproximately4to5percenthydrogenorless.Eachrecombinerunitcanprocessaninput(10)flowintherangeof100SCFMto200SCFM.Nithintheaccuracyofthismethodology,itisassumedthatrecombinerswillhaveaninsignificanteffectI'nthehydrogenconcentrationwhenitisindicatedthatextensivezirconium-steamreactioncouldhaveoccurred.Uncontrolledignitionofhydrogenanddeliberate-ignitionwillhinderanyquantitativeuseofhydrogenconcentrationasanauxiliaryindicator.However,theoxygenamountdepletedduringtheburn,ifknown,canbeusedtoestimatetheamountofhydrogenburned.Iftheoxygenamountdepletedisnotknown,itcanbeassumedthatforignitionofhydrogentooccuraminimalconcentrationof4percenthydrogenisneeded.SinceUnits1and2areicecondensercontainments,deliberateignitionofthehydrogenisutilizedtocontrolthecontainmenthydrogenconcentration.Asstatedabove,aminimalconcentrationof4percenthydrogenisneeded.Thisassumptioncanbeusedqualitativelytoindicatethatsomepercentageofzirconiumhasreacted,butitisdifficulttodeterminetheextentofthereaction.ContainmenthydrogenconcentrationscanbeobtainedfromthePostAccidentSamplingSystemorthecontainmentgasanalyzers.Figure3-1showstherelationshipbetweenthehydrogenconcentration(percentvolume)andthepercentageofzirconiumwaterreactionforUnit1andUnit2.Thehydrogenconcentrationshownistheresultoftheanalysisofadrycontainmentsample.Thecurveswerebasedonaveragecontainmentvolumesandtheaverageinitialzirconiummassofthefuelrodsforeachunit,whichareshowninTable3-1.Table3-1alsopresentsthecorrelationbetweenhydrogenconcentrationandpercentageofzirconiumwaterreaction.'ousetheauxiliaryindicatorofhydrogenconcentration,theassumptionswerethatallhydrogenfromzirconiumwaterreactionisreleasedtocontainment,awell-mixedatmosphere,andidealgasbehaviorincontainment.

30..25'0.C)Ii5~IoCJ<0~UNITUNIT1/"/OClZIRC-WATERREACTIONPERCENTAGEFIGURE3-1CONTAINMENTHYDROGENCONCENTRATIONBASEDONZIRCONIUMWATERREACTION55 TABLE3-1CONTAINMENTVOLUHEANOZIRCONIUHHASSPlantTeZirconiumHassibmContainmentVolumeSCFUnit1Unit244,54750,9131.2x1061.2x10'6Relationshipbetweenhydrogenconcentrationofadrysampleandfractionofzirconiumwaterreactionisbasedonthefollowingformula.~oo2(FZWR)(ZM)(H)+Vwhere:FZWR=fractionofzirconiumwaterreactionZM=totalzirconiummass,ibmH=conversionfactor,7.92SCFofHperpoundofzirconiumreactedV=containmentvolume,SCF 3e2COREEXITTEMPERATURESANDREACTORVESSELWATERLEVELSCoreexitthermocouples'(CETCs)measurethetemperatureofthefluidatthecoreexitatvarSousradSalcorelocations~<(FSgure3-2)J.Thetypicalthermocouplesystemisqualifiedtoreadtemperaturesashighas1650'F.Thisistheabilityofthesystemtomeasurethefluidtemperaturesattheincorethermocoupleslocationsandnotcoretemperatures.Mostreactorvessellevelindicationsystems(RVLIS)usedifferentialpressure(d/p)measuringdevicestomeasurevessellevelorrelativevoidcontentofthecirculatingprimarycoolantsystemfluid.Thesystemisredundantandincludesautomaticcompensationforpotentialtemperaturevariationsoftheimpulselines.Essentialinformationisdisplayedinthemaincontrolroominaformdirectlyusablebytheoperator.RVLISandCETCreadingscanbeusedforverificationofcoredamageestimatesinthefollowingways(11)'uetotheheattransfermechanismsbetweenthefuelrods,steam,andthermocouples,thehighestcladtemperaturewillbehigherthantheCETCreadings.Therefore,ifthermocouplesreadgreaterthan1300'F,cladfailuremayhaveoccurred.1300'Fisthelowerlimitforcladdingfailures.oIfanyRCPsarerunning,theCETCswillbegoodindicatorsofcladtemperaturesandnocoredamageshouldoccursincetheforcedflowofthesteam-watermixturewilladequatelycoolthecore.IfRCPsarenotrunning,thefollowingapply.oNogeneralizedcoredamagecanoccurifthecorehasnotuncovered.SoifRVLISfullrangeindicatesthatthecollapsedliquidlevelhasneverbeenbelowthetopofthecoreandnoCETChasindicatedtemperaturescorrespondingtosuperheatedsteamatthecorrespondingRCSpressure,thennogeneralizedcoredamagehasoccurred.57 QTQT00TT6-QOO0T0T90o8TJOTti0Tl3IQl5TOT0TOTTTTOT0TTQTOTO-2700'=FLUXTtttttSLET=THERHOCOUPL.EDistributionofThermocouplesandFluxThimblesforUnit1andUnit2'Figure3-258ttF~hX

oIfRVLISindicateslessthan3.5ft.collapsedliquidlevelinthecoreorCETCsindicatesuperheatedsteamtemperatures,thenthecorehasuncoveredandcoredamagemayhaveoccurreddependingonthetimeafterreactortrip,lengthanddepthofuncovery.Bestestimatesmallbreak(1to4inches)analysesandtheThreeMileIsland(TMI)accidentdata(12)indicatethatabout20minutesafterthecoreuncoverscladtemperaturesstarttoreach1200'Fand10minuteslatertheycanbeashighas2200'F.Thesetimeswillshortenasthebreaksizeincreasesduetothecoreuncoveringfasterandtoagreaterdepth.oIftheRVLISindicationisbetween3.5ftcollapsedliquidlevelinthecoreandthetopofthecore,thentheCETCsshouldbemonitoredforsuperheatedsteamtemperaturestodetermineifthecorehasuncovered.Asmanythermocouplesaspossibleshouldbeusedforevaluationofthecore(11)temperatureconditions.TheEmergencyResponseGuidelinesrecommendthataminimumofone'thermocouplenearthecenterofthecoreandoneineachquadrantbemonitoredatidentifiedhighpowerassemblies.Cautionshouldbetakenifathermocouplereadsgreaterthan1650'ForisreadingconsiderablydifferentthanneighboringCETCs.Thismayindicatethatthethermocouplehasfailed.CautionshouldalsobeusedwhenlookingatCETCsnearthevesselwallsbecauserefluxcoolingfromthehotlegsmaycoolthefluidinthisarea.CETCscanalsobeusedasanindicatorofhotareasinthecoreandmaybeusedtodetermineradiallocationofpossiblelocalcoredamage.Therefore,coreexitthermocouplesandRVLISaregenerallyregardedasreliableindicatorsofRCSconditionsthatmaycausecoredamage.TheycanpredictthetimeofcoreuncoverytowithinafewminutesbymonitoringthecoreexitthermocouplesforsuperheatafterRVLISindicatescollapsedliquidlevelatthetopofthecore.Theonsetandextentoffueldamageaftercoreuncoverydependontheheatgenerationinthefuelandtherapidityanddurationofuncovery.However,ifthecorehasnotuncovered,nogeneralizedfueldamagehasoccurred.Coreexitthermocouplesreading1300'Forlargerindicatethelikelihoodofcladdamage.59

3.3CONTAINHENTRADIATIONHONITORSANOCOREDAMAGEIpostaccidentradiationmonitorsinnuclearplantscanbeusedtoestimatethexenonandkryptonconcentrationsinthecontainment.AnanalysishasbeenmadetocorrelatethesemonitorreadingsinR/hrtoestimategaseousradioactivityconcentrations.Forthisanalysisthefollowingassumptionsweremade:1.Radiogasesreleasedfromthefuelareallreleasedtocontainment.2.Accidentswereconsideredinwhich100Kofthenoblegases,52Kofnoblegases,and0.3$ofthenoblegaseswerereleasedtothecontainment.3.Halogensandotherfissionproductsareconsiderednottobesignificantcontributorstothecontainmentmonitorreadings.Arelationcanbedevelopedwhichdescribesthegammarayexposurerateofadetectorwithtime,basedontheamountofnoblegasesreleased.Theexposureratereadingofadetectorisdependentonplantspecificparameters:theoperatingpowerofthecore,theefficiencyofthemonitor,andthevolumeseenbythemonitor.Theplantspecificresponseofthedetectorasafunctionoftimefollowingtheaccidentcanbecalculatedfromtheinstantaneousgammaraysourcestrengthsduetonoblegasrelease,Table3-2,andtheplantcharacteristicsoFthedetector.Thegamma.raysourcestrengthspresentedinTable3-2arebasedon100percentreleaseofthenoblegases.Todeterminetheexposurerateofthedetectorbasedon52percentand0.3percentnoblegasrelease,52percentand0.3percent,respectively,ofthegambiaraysourcestrengthareused.Alternately,theenergyratesinMev/watt-secgiveninTable3-2canbeexpressedintermsofaninstaneousfluxbyassumingtheenergyisabsorbedinacmoFair.Theseenergyratevalues,inMev/watt-sec-cm,whendivided33bydiscretevaluesofMev/photonandthegambiaabsorptioncoefficientforair,]-5-1p,consideredasaconstant(3.5x10cm),providevaluesofthephotonflux,photons/watt-cm-sec,asshowninTable3-2A.Thediscrete2valuesofHev/photonwereobtainedby'usingtheaveragevaluesoftheenergygroups,Hev/game,fromTable3-2.60

TABLE3-2INSTANTANEOUSGAMMARAYSOURCESTRENGTHSOUETOA100PERCENTRELEASEOFNOBLEGASESATVARIOUSTIMESFOLLOWINGANACCIOENTEnerGrouSourceStrenthatTimeAfterReleaseMe'v/watt-sec~mev/amma0Hours0.5Hours1Hour2Hours8Hours1.2x1091.5x1091.3x1091.8x1091.4x1091.3x1094.0x1083.5x1083.1x1070.20-0.400.40-0.900.90-1.351.35-1.801.80-2.202.20-2.602.60-3.003.00-4.004..00-5.005.00-6.000~~3.03.49.43.45.48.56.66.34.4x10x10x107x10x108x108x106x105x1002.6x1082.6x1086.7x1072.1x1083.6x1087.1x1085.1x1064'x1063.6x10202.4x1081.9x1084.7x1071.4x1072.4x1085.3x1083.5x1062.6x1062.0x1085.9x10-79.8x1062.9x1075.2x1071.1x1085.0x1059.7x10400m~ev/amma1Week1Month6Months1Year0.20-0.400.40-0.900.90-1.351.35-1.801.80-2.202.20-2.602.60-3.003.00-4.004.00-5.005.00-6.001.3x1081.1x1071.8x1055.5x1059.9x1052.0x1068.5x1033.0x1071.5x1041.5x1061.5x1001.5x10401.4x1040000000061

TABLE3-2AINSTANTANEOUS)AMMARAYFLUXESOUETO100'ARELEASEOFNOBLEGASESATVARIOUSTIMESFOLLOWINGANACCIDENTEnerGrou/2~Mev/amaa0Hours0.5Hours'IHour2Hours8Hours0.30.651,131.582.02.42.83.54.51.1x101.0x103.3x103.3x102.0x101.5x104.1x102.9x10121.9x10ll2.7x102.3x102.4x106.2x107.7x101.0x106.7x105.3x102.8x1082.4x101.7x101.7x103.8x105.1x108.4x105.2x103.8x102;3x102.2x101.3x101.2x102.5x10113.4x106.3x103.6x102.2x101.8x103.9x10122.5x105.3x107.4x101.3x105.1x108.1x100~Hev/amma~10a1Week1Heath6Months1Year0.30.651.131.582.02.42.83.54.51.2x107.3x10114.5x101.0x101.4x102.4x108.7x1072.7x101.0x101.4x10111.0x109001.0x10901.0x109000000062

Ingeneral,valuesbelow0.3$releasesareindicativeofcladfailures,valuesbetween0.3$and525releaseareintheFuelpelletovertemperatureregions,whilevaluesbetween525-releaseand100$releaseareinthecoremeltregime.TorepresentthereleaseofthenormaloperatingnoblegasactivityintheprimarycoolantasobtainedfromANS18.1,1.0x105ofthe(6)-3gammaraysourcestrengthisused.Inactualpracticeitmustberecognizedthatthereisoverlapbetweentheregimesbecauseofthenatureinwhichcoreheatingoccurs.ThehottestportionoFthecoreisinthecenterduetofluxdistributionandhencegreaterfissionproductinventory.Additionallyheattransferisgreateratthecoreperipheryduetoproximityofpressurevesselwalls.Thusconditionscouldexistwherethereissomemoltenfuelinthecenterofthecoreandovertemperatureconditionselsewhere.Similarconditionscanoccurwhichleadtoovertemperatureinthecentralportionsofthecore,andcladdamageelsewhere.Thus,estimationofextentofcoredamagewithcontainmentradiationreadingsmustbeusedinaconfirmatorysense-asbackuptoothermeasurementsoffissionproductreleaseandotherindicatorssuchaspressurevesselwaterlevelsandcoreexitthermocouples.Figure3-3presentstherelationshipofthereading(R/hr)ofUnit1andUnit2highrangecontainmentarearadiationmonitorsasafunctionoftimefollowingreactorshutdown.Eachunithastwohighrangemonitorswithonemonitormountedapproximately7feetabovetheoperatingfloorbetweenloop2andloop3steamgeneratordoghousesandtheothermonitormountedinthelowercompartmentontheoutsidecontainmentwall.63 1.0+71005NOBLEGASRELEASE1.0+552ÃNOBLEGASRELEAS1.0+30.35NOBLEGASRELEASEANS18.1NORMALOPERATINGNOBLEGASRELEASE1.01.0-2"1.010.0100.0TIMEAFTERSHUTDOWN(HOURS)fIGURE3-3PERCENTNOBLEGASESINCONTAINMENTFORUNIT1ANDUNIT264 4.0GENERALIZEDCOREOAMAGEASSESSMENTAPPROACHIISelectedresultsofvariousanalysesoffissionproductrelease,coreexitthermocouplereadings,pressurevesselwaterlevel,containmentradiogasmonitorreadingsandhydrogenmonitorreadingshavebeensummarizedinTable4-1.Theintentofthesummaryistoprovideaquicklookatvariouscriteriaintendedtodefinecoredamageoverthebroadrangesof:NoCoreDamage0-50K50-100%0-50$50-100%0-50550-100'XcladfailurecladfailurefuelpelletovertemperaturefuelpelletovertemperaturefuelmeltfuelmeltIAlthoughthistableisintendedforgenericapplicabilitytomostMestinghousepressurizedwaterreactors,exceptwherenoted,variouspriorcalculationsarerequiredtoascertainpercentagereleasefractions,power,andcontainmentvolumecorrections.Thesecorrectionsaregivenwithinthepriortextofthistechnicalbasisreport.Theusershoulduseasmanyindicatorsaspossibletodifferentiatebetweenthevariouscoredamagestates.Becauseofoverlappingvaluesofreleaseandpotentialsimultaneousconditionsofcladdamage,overtemperature,and/orcoremelt,considerablejudgementneedstobeapplied.II65 TABLE4-1CHARACTERISTICSOFCATEGORIESOFFUELOAHAGE*CoreDamageIndicatorCoreDamageCategoryPercentandTypeofFissionProductsReleasedFissionProductRatioContainmentRadiogasHonitor(R/hr)10hrsaftershutdown**CoreExitThermocouplesReadings(oegF)CoreUncoveryIndicationNydrogenHonitor(VolyH2)***6PlantTypeNocladdamage0-50$claddamage50-100KcladdamageKr-87<lx103Xe-133<lxl03l-131<lxl0"3I-133<lx'103Kr-8710-3-0.01Xe-133103-O.lI-131103-0.3l-133103-0.1Kr-87D.Dl-0.02Xe-133O.l-0.21-1310.3-0.51-1330.1-0.2NotApplicableKr-$70.0221-1330.71Kr-87~0.022I"133~0.710-660660to1325<750750-13001300-1650NouncoveryCoreuncoveryCoreunqoveryNeg1Igible0-\313-240-50$fuelpelletovertemperature50-TOOLfuelpelletovertemperature0-50Kfuelmelt50-100KfuelmeltXe-Kr.Cs,I1"20Sr-Ba0-O.lXe-Kr,Cs,I2D-40Sr-BaO.l-0.2Xe,Kr,Cs,I4D-7DSr-Ba0.2-0.8Pr0.1-0.8Xe,Kr,Cs,I,Te>70Sr,Ba>24Pr>0.8Kr-870.221-133R2.1Kr-870.221-13302.1Kr-87~0.221-133~2.1Kr-87~0.22I-133~2.11325to1.7(5)>16501.7(5)to3.4(5)>165D5.8(5)>\6503.4{5)to5.8{5)>1650CoreuncoveryCoreuncoveryCoreuncoveryCoreuncovery13-2413-2413-2413-24"ThistableisintendedtosupplementthemethodologyoutlinedinthisreportandshouldnotbeusedMithoutreferringtothisreportandwithoutconsiderableengineering)udgement.""Valuesshouldberevisedpertimesotherthan10hours.***Ignitorsmayobviatethesevalues.Ail*-Lrr-87~-133Xe-133'-131 5.0LIHITATIONSTheemphasisofthismethodologyisonradiochemicalanalysisofappropriateliquidandgaseoussamples.Theassumptionhasbeenmadethatappropriatepost-accidentsystemsareinplaceandfunctionalandthatrepresentativesamplesareobtained.Ofparticularconcern,intheareaofrepresentativesampling,isthepotentialforplateoutinthesamplelines.Inordertoprecludesuchplateout,itisassumedthatproperattentiontoheattracingofthesamplelinesandmaintenanceofsufficientpurgevelocitiesisinherentinthesamplingsystemdesign.Havingobtainedarepresentivesample,radiochemicalanalysisviagammaspectrometryareusedtocalculatethespecificactivityofvariousfissionproductsreleased.Radiochemicalanalysesoffissionproductsundernormalplantoperatingconditionsareaccurateto+10percent.Radiochemicalanalysesofpostaccidentsampleswhichmaybemuchmoreconcentrated,andcontainunfamiliarnuclides,andwhichmustbeperformedexpeditiouslymayhaveanerrorbandof20to50percent.Havingobtainedspecificactivity-analysis,thecalculationoftotalreleaserequiresknowledgeofthetotalwatervolumefromwhichthesamplesweretaken.Caremustthusbeexercisedinaccountingforvolumesofanywateradded.viaECCSandspraysystems,accumulators,chemicaladditiontanks,andmeltingiceoficecondenserplants.Additionallyestimatesoftotalsumpwatervolumeshavetobedeterminedwithdatafromsumplevelindicators.Suchestimatesofwatervolumeareprobablyaccurateto+10percent.Thespecificactivityalsorequiresacorrectiontoadjustforthedecayofthenuclideinwhichthemeasuredspecificactivityisdecaycorrectedtotime.ofreactorshutdown.Forsomenuclides,precursoreffectsmustbeconsideredinthedecaycorrectioncalculations.Theprecursoreffectislimitedtoparent-daughterrelationshipsforthismethodology.Amajorassumptionismadethatthereleasepercentagesoftheparentanddaughterareequal.Forovertemperatureandmeltreleases,thisassumptionisconsistentwiththetechnicalbasispresentedinSections2.5and2.6,butthegapreleasescouldbedifferentbyasmuchasafactorof2.67 ThemodelsusedforestimationoffissionproductreleasefromthegapactivityarebasedontheANS5.4standard.Backgroundmaterialforthis,reportindicatethemode(,thoughempirical,isbelievedtohaveanaccuracyof20-25percent.Inourapplicationofthesemodelstocorewideconditions,thecorehasarbitrarilybeendividedintothreeregionsoflow,intermediate,andhighburnup.Thisrepresentationpredictednominalvaluesofreleasewithmaximumandminimumvaluesthatapproach+100percentofthenominalvalue.Thereforetheseestimatesofcoredamageshouldonlybeconsideredaccuratetoafactorof2.Themodelsemployedforestimatesofreleaseathighertemperaturehavenotbeencompletelyverifiedbyexperiment.Additionally,calculationsofexpectedcoretemperaturesforsevereaccidentconditionsarestillbeing'efined.Theseuncertaintiesareexacerbatedbythemannerinwhichvariousaccidentscenariosleadingtocoremelthavebeencombinedtoproducefissionproductreleasepredictionsforthecoremeltcondition.ConsiderationofthemeltreleaseestimatesshowninTable2-11fortherefractorynuclidesindicatearangeofapproximately+70percent.Fromtheseconsiderationsitisclearthatthecombineduncertaintiesaresuchthatcoredamageestimatesusingthismethodologyaresufficientonlytoestablishmajorcategoriesoffueldamage.Thiscategorization,andconfirmationofsubcategorizationwillrequireextensiveadditionalanalysisforsomeseveraldayspasttheaccidentdate.68

7.0REFERENCES

1."ClarificationofTHIActionPlanRequirements,"NUREG-0737,USNRC,November1980.2."AReporttotheCommissionandtoPublic,NRCSpecialInquiryGroup,"H.Rogovin,1980.3."ORIGENIsotopeGenerationandDepletionCode,"OakRidgeNationalLaboratory,CCC-217.4.Methodofcalculatingthefractionalreleaseoffissionproductsfromoxidefuel,ANSI/ANS5.4-1982.5."IodineandCesiumSpikingSourceTermsforAccidentAnalyses,"WCAP-9964,WestinghouseElectricCorporation,July1981.6."SourceTermSpecification,"ANS18.1Standard1976.7."RadionuclideReleaseUnderSpecificLWRAccidentConditions,"DraftNUREG-0956,USNRC,January1983.8."ReleaseofFissionProductsFromFuelinPostulatedDegradedAccidents,"IOCORDRAFTReport,July1982.9."THI-2Accident:CoreHeat-upAnalysis,"NSAC/24,January1981.10."LightWaterReactorHydrogenManual,"NUREG/CR-2726,August1983.11."WestinghouseOwnersGroupTransmittalofVolumeIIIforHighPressureofEmergencyResponseGuidelines,"0.0.Kingsley,Jr.to0.G.Eisenhut,LetterNo.OG83,SectionFR-C.l,January1983.69 12.AnalysisoftheThreeMileIslandAccidentandAlternativeSequences,PreparedforNRCbyBattelle,ColumbusLaboratories,NUREG/CR-1219,January1980.13.WestinghouseOwner'sGroupPostAccidentCoreDamageAssessmentMethodo1ogy,Revision1,March,1984.70 INDIANAhMICHIGANELECTRICCOMPANYDONALDC.COOKNUCLEAR.PLANTUNIT1ANDUNIT2POSTACCIDENTCOREDAMAGEASSESSMENT1.0OBJECTIVE1.1Thepurposeofthisprocedureisto'rovideamethodtoclassifyandestimatetheextentofcoredamagethroughmeasurementoffissionproductsreleasedtothecoolantandcontainmentatmospheretogetherwithauxiliarymeasurementsofcoreexitthermocoupletemperature,waterlevelwithinthepressurevessel,containmentradiationmonitors,andcontainmentatmospherehydrogenmonitors.

2.0REFERENCES

2.1MestinghouseOwnerGroupPostAccidentCoreDamageAssessmentMethodology,Revision1,March1984.3.0RESPONSIBILITIES3.1ThePlantEvaluationTeamintheTechnicalSupportCenterwillberesponsibleforcoredamageassessmentbasedonradionuclideanalysisandauxiliarymeasurements.4.0APPLICABILITY4.1Anyplant.conditioninwhichtheoperatorwouldsuspectalossofreactorcorecoolingorreactorcorecoolingcannolongerbemaintained.4.2Anyplantconditioninwhichtheoperatorwouldsuspectfailedfuel,andanestimateoftheamountoffailedfuelisrequired.

5.0INSTRUCTIONS5.1NuclideSampling5'.1Requestsamplesofreactorcoolant,containmentatmosphere,andcontainmentsumpasindicatedinTable2.Table11'iststheselectednuclidesforcoredamageassessment.5.1.2Analyzetheselectedsamplesforisotopicspecificactivitywithnodecaycorrectionappliedtosampleactivities.5.1.3CompleteTable3A,RCSActivityWorksheet,ifsamplewasavailableasfollows:5.1.3.1Recordelapsedtimefromreactorshutdowntosamplecount.5.1.3.2RecordspecificactivitiesofnuclidesinCi/gm.5.1.3.3DetermineandrecorddecaycorrectionfactorusingTable.4,DecayCorrectionFactorWithParent-DaughterEffect.95.1.3.4Determineandrecordthecorrectedspecificactivitybymultiplyingthemeasuredspecificactivitybythedecaycorrectionfactor.5.1.4CompleteTable3B,ContainmentSumpActivityWorksheet,ifsamplewasavailable,asfollows:5.1.4.1Recordelapsetimefromreactorshutdowntosample.count.

5.1.4.2Recordspecificactivitiesofnuclides.5.1.4.3OetermineandrecorddecaycorrectionfactorusingTable4,OecayCorrectionFactorWithParent-OaughterEffect.5.1.4.4Oetermineandrecordthecorrectedspecificactivitybymultiplyingthemeasuredspecificactivitybythedecaycorrectionfactor.5.1.5CompleteTable3C,ContainmentAtmosphereActivityWorksheetasfol1ows:5.1.5.1Recordelapsetimefromreactorshutdowntosamplecount.5.1.5.2Recordspecificactivitiesofnuclides.5.1.5.3OetermineandrecorddecaycorrectionfactorusingTable4,OecayCorrectionFactorWithParent-OaughterEffect.5.1.5.4Oetermineandrecordthecorrectedspecificactivitybymultiplyingthemeasuredspecificactivitybythedecaycorrectionfactor.5.2LiquidMass5.2.1EstimatethetotalliquidmassbycompletingTable5,EstimateofTotalLiquidMassWorksheet.5.2.2IfbothaRCSsampleandacontainmentsumpsamplewasobtained,anestimateoftheRCSwatermassandcontainmentwatermassisneeded.UseTable6,EstimateofRCSWaterMass andContainmentWaterMassWorksheettoestimatethedistributionofthewater.RecordtheRCSmassinTable3AandthecontainmentmassinTable3B.5.2.3Ifonlyoneoftheliquidsamples(RCSorcontainmentsump)wasobtained,usethetotalliquidmasscalculatedin5.2.1asthewatermassassociatedwiththatsample.RecordwaterineitherTable3A(RCS)orTable3B(containmentsump).t5.3ContainmentVolume5.3.1Sincethecontainmentatmospheresampleiscollectedatthecontainmentbuildingpressureandthesamplevolumeisnotcorrectedtostandardconditions,noadjustmentfactorisneededtotheknowncontainmentvolume.Theknowncontainmentvolume(3.5xl0cc)isrecordedinTable3C.105.4TotalActivityReleased5.4.1RCS5.4.1.1CalculatetotalactivityofeachnuclidereleasedtotheRCSbymultiplyingthedecaycorrectedspecificactivitybytheRCSmass.RecordinTable3A.5.4.2ContainmentSump5.4.2.1Calculatetotalactivityofeachnuclidereleasedtothecontainmentwaterbymultiplyingthedecaycorrectedspecificactivitybythecontainmentwatermass.RecordinTable3B.

5.4.3ContainmentAtmosphere5.4.3.1Calculatetotalactivityofeachnuclidereleasedtothecontainmentatmospherebymultiplyingthedecaycorrectedspecificactivitybythecontainmentvolume.RecordinTable3C.5.4.4TotalActivityReleasedofEachNuclide5.4.4.1RecordinTable7,TotalReleaseActivity/PercentReleased,theactivityofeachnuclideofeachsamplelocation.5.4.4.2Sumtheactivitiesofeachnuclideofeachsampletodeterminetotalactivityreleasedofeachnuclide,RecordinTable7.5.5TotalCoreInventory5.5.1PowerHistory5.S.1.1RecordinTable8,PowerCorrectionFactor,theplantpowerhistoryduringthe30dayspriortoshutdown.5.5.2PowerCorrectionFactor5.5.2.1Ifpowerhistoryindicatessteadystatepowerlevelduringthe30daysor4days(dependingonthenuclide)priortoshutdown,usethesteadystatepowercorrectionequationshowninTable8todeterminepowercorrectionfactor(PCF).RecordinTable7.5.S.2.2Ifpowerhistoryindicatesfluctuatingpowerlevelsduringthe30dayspriortoshutdown,usethetransientpowercorrectionequationshowninTable8todeterminepowercorrectionfactor(PCF).RecordinTable7.

5.5.2.3TodeterminethepowercorrectionfactorforCs-134firstdeterminetheaveragepowerduringtheentireoperatingperiodduringthecyclepriortoshutdown.UsethisaveragepowerandFigure4toestimatepowercorrectionfactor.RecordinTable7.5.5.3AdjustedCoreInventory5.5.3.1DetermineandrecordinTable7theadjustedcoreinventoryforeachnuclidebymultiplyingtheequilibriumfull-powerinventory(listedinTable7)bythepowercorrectionfactor.5.6EstimationofPercentFuelDamage5.6.1Determinethepercentageofthecorrectedcoreinventoryreleasedofeachnuclidebydividingthetotalactivityreleasedbythecorrectedcoreinventory.RecordinTable7.5.6.2Usingtheappropriatecoredamagegraphs,Figures5through17,determinethepercentcladfailure,fuelovertemperature,andfuelmeltasafunctionofthenuclidereleasepercentage.Usethecurvethatbestrepresentscoreburnup.Recordthepercentagesofcladdamage,fuelovertemperature,andfuelmeltinTable10,CoreDamageAssessmentEvaluationSheet.Note:Iodinespikingshouldbeconsideredforcaseswheretheassessmentisbetweennofueldamageandminorcladfailure.Ifpercentcladfailureisnotinagreementwithvaluesobtainedfromothernuclides,spikingmayhaveoccurred.RefertoFigure8ifthisisthecase..5.7NuclideActivityRatios5.7.1DeterminetheactivityratiosfornoblegasesandiodinesbycompletingTablell,NuclideActivityRatios.

5.7.2ComparethecalculatedactivityratioswiththegapactivityratiosandfuelpelletratioslistedinTablell.Calculatedactivityratioslessthangapactivityratiosareindicativeofcladfailures.Calculatedactivityratiosgreaterthangapactivityratiosareindicativeofmoreseverefailures(fueloverheatandfuelmelt).5.7.3RecordinTable10thecalculatedcoredamagestate.5.8AuxiliaryIndicators5.8.1Oeterminefromreactorvessellevelinstrumentationorothersourcesifatanytimethecorebecameuncovered.Nouncoveryisindicativeofnofueldamage,andcoreuncoveryisindicativeofallcoredamagestates.RecorduncoveryhistoryinTable10.5.8.2ObtaincoreexitthermocouplereadingsandcomparethesevalueswiththoselistedinTable12.8asedonTable12,CharacteristicsofCategoriesofFuelOamage,recordtemperatureinTable10underappropriatecoredamagestate.5.8.3Obtaincontainmenthydrogenconcentration.Comparehydrogenconcentrationhydrogenconcentrationunderappropriatecoredamagestate.5.8.4UsehydrogenconcentrationwithFigure18todetermineextentofzirconium-waterreaction.RecordpercentageofzirconiumwaterreactioninTable10.Note:Ifignitorshavebeenactivatedoraburnhasbeenindicated,quantitativeuseofthehydrogenconcentrationislimited.Itcanbeassumedthatforignitionofhydrogentooccuraminimalconcentrationof4percenthydrogenisneeded.Thisassumptioncan beusedqualitativelytoindicatethatsomepercentageofzirconiumhasreacted,butitisdifficulttodetermineextentofthereaction.5.8.5Obtainthecontainmenthighrangearearadiationmonitorreadingsandthetimeaftershutdownthereadingswereobtained.ComparethereadingswithFigure19toestimatethecorrespondingextentofcoredamage.RecordthemonitorreadinginTable10undertheappropriatecoredamagestate.5.9CoreDamageAssessment5.9.1PerformthefinalcoredamageassessmentbyevaluatingthedatainTable10.Itisunlikelythatcompleteagreementbetweentheindicatorswillresultinthesameestimateofcoredamage.Theevaluationshouldbethebestestimatebasedonallparameters,theirinterrelationship,andengineeringjudgment.Theusershoulduseasmanyindicatorsaspossibletodifferentiatebetweenthevariouscoredamagestates.Becauseofoverlappingvaluesofreleaseandpotentialsimultaneousconditionsofcladdamage,overtemperature,and/orcoremelt,considerablejudgementneedstobeapplied.

TABLE1SELECTEONUCLIOESFORCOREDAMAGEASSESSMENTCoreDamageStateNuclideHalf-Life*PredominantGamasKevYieldX*CladFailureFuelOverheatFuelMeltKr-85m**Kr-87Kr-88**Xe-131mXe-133Xe-133m**Xe-135*+I-131I-132I-133I-135Rb-88Cs-134Cs-137Te-129Te-132Sr-8990**Ba-140La-140La-142Pr-1444.4h76m2.8h11.8d5.27d2.26d9.14h8.05d,2.26h20.3h6.68h17.8m2yl30yr68.7m77.7h52.7d28yr12.8d40.22h92.5m17.27m150(74),305(13)403(84),2570(35)191(35),850(23),2400(35)164(2)81(37)233(14)250(91)364(82)773(89),955(22),1400(14)530(90)1140(37),1280(34),1460(12),1720(19)898(13),1863(21)605(98),796(99)662(85)455(15)230(90)(betaemitter)(betaemitter)537(34)487(40),815(19),1596(96)650(48),1910(9),2410(15),2550(11)695(1.5)*Val.uesobtainedfromTableofIsotoes,Lederer,Hollander,andPerlman,-SixthEdition.**Thesenuclidesaremarginalwithrespecttoselectioncriteriaforcandidatenuclides;theyhavebeenincludedonthepossibilitythattheymaybedetectedandthusutilizedinamanneranalogoustothecandidatenuclides, TABLE2SuestedSamlinLocationsScenarioPrincipalSamlinLocationsOtherSamlinLocationsSmallBreakLOCAReactorPower>lg*ReactorPower<lg*LargeBreakLOCAReactorPower>lg*ReactorPower<lX*RCSHotLeg,ContainmentAtmosphereRCSHotLegContainmentSump,ContainmentAtmosphere,RCSHotLegContainmentSump,ContainmentAtmosphereRCSPressurizerRCSPressurizerSteamLineBreakSteamGeneratorTubeRuptureIndicationofSignifi-cantContainmentSumpInventoryRCSHotLeg,RCSHotLeg,SecondarySystemContainmentSump,ContainmentAtmosphereRCSPressurizerContainmentAtmosphereContainmentAtmosphereContainmentBuildingRadiationMonitorAlarmSafetyInjectionActuatedContainmentAtmosphere,ContainmentSumpRCSHotLegRCSPressurizerIndicationofHighRadiationLevelinRCSRCSHotLegRCSPressurizerl'I*Assumeoperatingatthatlevelforsomeappreciabletime.

TABLE3ARCSACTIVlTYMORKSMEElNuclideElapseTimeShutdowntoSampleCountthoursMeasuredSpecificActivityCorrectedOecayCorrectionSpecificActivityRCSMassRCSActivityFactorCi/m~msCiKr85mKr87Kr88Xe131mXe133Xe133mXe13511311132I1331135Rb88Cs134Cs131Te129Te132Ba140La\40La142Pr144 TABLE38CONTAINHEHTSUHPACTIVITYWORKSHEETHuc1ideElapseTimeShutdowntoSampleCountthoursMeasuredSpecificActivityCi/msOecayCorrectionFactorCorrectedContainmentContainmentSpecificActivityWaterHassMaterActivity~IIISCiKr85mKr81Kr88Xe131mXe133Xe133mXe135I131I132I133I135Rb88Cs134Cs131Te129Te132Ba140La140La142Pr144 TABLE3CCONTAIHHEHTATHOSPHEREACTIVITYNDRKSHEETHucdeElapseTimeShutdowntoSampleCountthoursHeasuredSpecificActivityCorrectedContainmentContainmentDecayCorrectionSpecificActivityVolumeActivityFactor~CIccCCCiKr85mKrBTKr88Xe131mXe133Xe133mXe135I131I132I133I135Rb88Cs134Cs137Te129Te132Ba140La140La142Pr144 TABLE4DECAYCORRECTIONFACTOR*WITHPARENT-DAUGHTEREFFECTNuclideCorrectionFactorKr85mKr87Kr88Xe131mXe133Xe133mXe135I131I132I133Rb88Cs134Cs134Te129Te132Ba140La140La142Pr1440.158te'.547te0.248te(-3.59E-3)t6(-2.45E-3)t1/-01873.41E-2)t0105.48E-3)t+1287(-1.2E-2)t1/0103.41E-2)t1111.28E-2)t1/914(-1.04E-1)t0033(2.67)t+10177.58E-2)t(3.59E-3)te1/103'003(3.41E-2)te0.104te110(0248t010234t1.01.01/109(-0.161)t0167(-8.47E-4)t-0257(0.605)t(8.92E-3)te(2.26E-3)te08(2e26E3)t008(1a72E2)t1/0145378)t114(0450)t1/0909102E4)t0091(2.41)t*Time,t,isthenumberofhoursbetweenshutdownandtimeofsamplecount.

TABLE5'ESTIMATEOFTOTALLIgUIOHASSl.Estimatethevolumeaddedforthefollowing:Tanka.RefuelingWaterStorageTankb.AccumulatorAc.AccumulatorBd.AccumulatorCe.Accumulator0f.BoronInjectionTankg.SprayAdditiveTankh.OthersourceEstimatedVolumeAddedMaximumVolume~d372,250-7,2637,2637,2637,2639004,000Totali.MeltedIceEstimatedMassAddedHaximumHassAdded(ibm)2.7xl062.Convertestimatedvolumeaddedfromgallonstograms.Addedvolume:,gallonsx3785gms/gal=gms3.Converticemeltedmassfromibmtograins,ibmx454grams/ibm=gms4.TheaverageReactorCoolantSystemMassis2.40x10gms.85.OeterminetheTotalLiquidMassasfollows:Massadded+RCSmass2.4x10gms=8gms+meltedicemassgmsgms

TABLE6KSTIHATEOF.RCSMATERHASS~ANDCONTAINHENTMATERHASSAVERAGEOPERATINGRCSVOLUHE=ll,780ft31.Recordthereactorvessellevel,pressurizer1evel,andRCStemperatureattimewhensamplewastaken.Reactorvessellevel=PressurizerlevelRCStemperatureoF2.DetermineRCSvolumeattime'ofsamplebyestimatingfromlevelindicationsthepercentageofwaterintheRCS.ftxX+1003.DetermineRCSspecificgravityfromFigurel.RCSspecificgravity=4.DetermineRCSmassasfollows:3~1.028.3x10cc3RCSvolume(ft)xspecificgravityx~xccft3ftx~1.028.3x10cc3xxccft35.RecordtheContainmentSumplevelindicationandthecontainmentlevelindication.ContainmentSumpLevel=ContainmentLevel TABLE6(Continued)ESTIMATEOFRCSWATERMASS*ANDCONTAINMENTWATERHASSrAVERAGEOPERATINGRCSVOLUME=11,780ft,36.DeterminecontainmentwatervolumefromFigures2and3usingthelevelsfromStep5.Note:IfsumplevelindicatessumpisfulluseFigure3.ContainmentWaterVolume=7.DeterminecontainmentwaterspecificgravityfromFigurel.Containmentwaterspecificactivity=8.Determinecontainmentwatermassasfollows:1.0m28.3x10cc3Containmentwatervolumexspecificgravityx'ccft3ftx1.0gm28.3x10cc3XXCCgms"Ifareactorvessellevelindicationisnotavailableorisconsiderinaccuratebasedonengineeringjudgmentssubtracttheestimatedcontainmentwatermassfromtheestimatedtotalwatermass(Table5)todetermineRCSwatermass.TotalWaterHass=RCSmassgIllSgms-containmentwatermassgills TOTALRELEASEACTIVITY/PERCEHTRELEASED-UHIT1RCSContainmentContainmentTotalEquilibriumCorrectedActivitySumpActivityAtmosphereActivityActivityCoreInventory*PowerCorrectionCoreInventoryReleasePercentage*guuc)decl~cCiC%CiFactorCiKr85mKR87Kr88Xe131mXe133Xe133mXe135I'l31I132I133I135Rb88Cs134Cs137Te129Te132Ba140La140La142Pr1442.0(7)3.6(7)5.2(7)5.7(5)1.8(8)2.5(7)3.4(7)8.9(7)1.3(8)1.8(8)1.6(8)5.3(7)2.1(7)1.0(7)3.0(7)1.3(8)1.5(8)1.6(8)1.4(8)1.1(8)*2.0(7)2.0x10.Thisnotationisusedthroughouttheprocedure.7**ReleasePercentageTotalActivitCorrectedCoreInventoryx100 TABLE78TOTALRELEASEACTIVITY/PERCENTRELEASED-UNIT2RCSContainmentActivitySumpActivityI~tueldeClCiContainmentAtmosphereActivityCiTotalActivityCiEquilibriumCoreInventory*CiPowerCorrectionFactorCorrectedCoreInventoryCiReleasePercentage"Kr85mKr87Kr88Xe131mXe133Xe133mXe135I131I132I133I135Rb88Cs134Cs137Te129Te132Ba140La140La142Pr1442.1(7)3.8(7)5.4(7)6.0(5)1.9(8)2.7(7)3.5(7)9.3(7)1.3(8)1.9(8)1.7(8)5.5(7)2.2(7)1.0(7)3.1(7)1.3(8)1.6(8)1.7(8)1.4(8)1.1(8)**ReleasePercentagex100TotalActivitCorrectedCoreInventory TABLE8POWERHISTORYOF30DAYSPRIORTOSHUTDOWNIntervalAveragePowerLevel*PjOperatingPeriodatPjtjhoursPeriodBetweenendoftjandReactorShutdowntjhoursPowerCorrectionFactorPCF**Stead-StatePowerConditionPCFTransientPowerConditionPCFI.Half-LifeofNuclide<1DaAveraePowerLevelHWtforrior4dasRatedPowerLevel(Hwt)-Xt-Lit'P(1-ej)eRatedPowerLevel(HWt)II.Half-LifeofNuc1ide>1DaAveraePowerLevelHWtforrior30dasRatedPowerLevel(Hwt)KP(1ejj)eijRatedPowerLevel(HWt)III.Half-LifeofNuclide-1YearAveraePowerLevelHWtforrior1earRatedPowerLevel(HWt)EffectiveFullPowerDasEFPDTotalCalendarDaysofCycleOperation*AveragePowerLevelisdefinedasthepowerlevelatwhichthepowerleveldoesnotvarymorethan+10percentoftheratedpowerlevelfromthetimeaveragedvalue.**)i=decayconstantinhours1.ofeachnuclide.XiofeachnuclideislistedinTable9.

TABLE9Nuc1ideOEGAYCONSTANTS(ki)OFEACHNUCLIOEHalf-Life-1hoursKr85mKr87Kr88Xe131mXe133Xe133mXe135I131,I132I133I135Rb88Cs134Cs137Te129Te132Ba140La140La142Pr1444.4h76m2.8h11.8d5.27d2.26d9.14h8.05d2.26h20.3h6.68h17.8m2yr30yr68.6m77.7h12.8d40.22h92.5m17.27m0.1580.5470.2482.45{-3)5.48{-3)1.28{-2)7.58(-2)3.59(-3)0.3073.41(-2)0.1042.343.96(-5)2.64(-6)0.6058.92(-3)2.26(-3)1.72(-2)0.4502.41 TABLE10COREOAMAGEASSESSMENTEVALUATIONSHEETIndicatorPercentCladDamaePercentOvertemeraturePercentFuelMelt<505>50%<50'A>505<50%>50$RadionuclideAnalsisKr85mKr87Kr88Xe131mXe133Xe133mXe135I131I132I133I135Cs134Cs137Te129Te132Ba140La140La142Pr144RatiosKr85m/Xe133Kr87/Xe133Kr88/Xe133Xe131m/Xe133 TABLE10(Continued)CORE'AMAGEASSESSMENTEVALUATIONSHEETIndicatorPercentCladDamaePercentOvertemeraturePercentFuelMelt505>505'50'g>50'A<50%>505Ratio(Con't)Xe133m/Xe133Xe135/Xe133I132/I131I133/I131I135/I131AuxiliarIndicatorsCoreUncoveredCoreExitTemp'FContainmentH5Zirc-WaterReaction5IgnitorsOn?HighRangeContainmentMonitorReadingR/hr TABLE11NUCLIOEACTIVITYRATIOSNuclideGapFuelPelletActivitRatioCalculatedActivitRatio+Kr85mKr87Kr88Xe131mXe133Xe133mXe1350.0220.0220.0450.0041.00.0960.0510.110.220.290.0041.00.140.19I131I132I133I1351.00.170.710.391.01.52.11.9NobleGasNuclideReleasedCiXe-133Released(Ci)IodineNuclideReleasedCiI-131Released(Ci)

TABLE12CHARACTERISTICSOFCATEGORIESOFFUELOAHAGE*CoreOamageIndicatorCoreOamageCategoryKocladdamage0-50KcladdamagePercentandTypeofFissionProductsReleasedKr-BT<lxl03Xe-133<lx1031-131<lx103I-133<lxl03Kr-81103-0.0)Xe-133103-O.lI"131103-0.31-133103-0.1FissionProductRatioHotApplicableKr-BT0.0221-1330.11ContainmentRadiogasNonitor(R/hr)10hrsaftershutdown*"0-660CoreExitThermocouplesReadings(BegF)<750150-1300CoreUncoveryIndicationHouncoveryCoreuncoveryHydrogenHonitor(VolKHq)**~6PlantTypeNegligible0-1350-100KcladdamageKr-810.01-0.02Xe-133D.l-0.21-1310.3-0.5I-1330.1-0.2Kr-810.022660to1325I-1330.711300-1650Coreuncovery13-2i0-50$fuelpelletovertemperature50-100Kfuelpelletovertemperature0-50$fuelmeltI50-IOOXfuelmeltXe-Kr,Cs,I)-20Sr-Ba0-O.lXe-Kr,Cs,l20-40Sr-BaO.l-0.2Xe,Kr,Cs,l10-70Sr-Ba0.2-0.8PrO.l-0.8Xe,Kr,Cs,I,Te>TOSr,Ba>2iPr>0.8Kr-87~0.22l-133~2.1Kr-BT0.22I-1332.1Kr-81~0.22I-1332.1Kr-870.221-1332.11.1(5)to3.I(5)>16503.4(5)to5.8(5)>16505.8(5)>16501325to1.1(5)>1650CoreuncoveryCoreuncoveryCoreuncoveryCoreuncovery13-2i13-2413-2413-21*Thistableisintendedtosupplementthemethodologyoutlinedinthisreportandshouldnotbeusedwithoutreferringtothisreportandwithoutconsiderableengineering)udgement.**Valuesshouldberevisedpertimesotherthan10hours."**Ignitorsmayobviatethesevalues.**@aKLOLLlRXe-133'-131

800.700.600.500~A400ClCl3008I-200~/oSTPFiGURE1MATEROENSITYRATIO(TEMPERATUREVSSTP) 90'0'O~50'0,30~20'p.0~'IOLVNE.Ft3FIGURE2SUMPWATERVOLUMEVERSUSSUMPLEVELINDICATION 90..80.70'460~CDCDICD50~40,20'DCDCDCD'NCDCDCDCDCDCDCDCDCQCDOCDCaCDCDCDCDCDCDCDCDCDFIGURE3CONTAINMENTWATERVOLUMEVERSUSCONTAINMENTLEVELINDICATION 1.00.990KPOWERO.e;RCORRECTION-ACTOR75$POWER0.60.50.40.30.20.10.02004006008001000CYCLEOPERATION(CALENDAR.DAYS)FIGURE4POWERCORRECTIONFACTORFORCS-134BASEDONAVERAGEPOWERDURINGOPERATION

0.1F07F05~03~02F01.007.005.003.002ou)~001CIJt57'-4Ol5'-4o3.0-4~),2.0-CJ'<e~/J'C~o+P1'-407~0-53'-520-51~0"5CVY)O'Ihh.OOCV'60h.OO~0CV0O0lhh0CladDamage(5)FIGURE5RELATIONSHIPOFXCLADDAMAGEWITH5COREINYENTORYRELEASEDOFKR-87 0.70.50.30'5OCP~02F01O~007.0050,1F07OlF05CJ~03///////re(a%eeo~ro+.003002.001lCV')Ill~~~~~i~~~~~~~IAh0000000~0000CVYlIhhQCladDamage(X)FIGURE6RELATIONSHIPOFXCLADDAMAGEWITHXCOREINVENTORYRELEASEDOFXE-131M 0.70~50.30~2F1~0705~03e.02CYoapl,pprOl~o.005.003.002////~~0)e<r~a~rrrq4ioF001oCVY)~Ihh~~~~~~~~~~~cvY)vlhooo00o.00.0~o,,~.~,.~~cvr)Int0CladDamage(5)FIGURE7RELATIONSHIPOFXCLADDAMAGEMITHXCOREINVENTORYRELEASEDOFXE-133 I~0T.0.50'0.20~I~OT.05~03.02F01.OOTF005~003002SoF001T~0-4QJ5'-4cs3'-4o2'-4r~~0)gQrgOI~0-4T.O"55'.0-53'"52'-51.0-5ocv~~~~~0~~CVYlIOh.oo00CladDamage(g)o0o0ocvneroFIGURE8RELATIONSHIPOF5CLADDAMAGEWITHXCOREINVENTORYRELEASEDOFI-131 I~0'0.50.3020~I~07~0503~02~01.007.005~003.002S-OF0017'-45'-4CJ~3.0-<02'-4~go9qOrergO+rI~0-47'-55'"53'-52'-5'I~0-.5CIAh.~~~~~~~~CVYlNh000O000DOcvnn~oCladDamage(X)FIGURE9RELATIONSHIPOFXCLADDAMAGEWITHXCOREINVENTORYRELEASEDOFI-131WITHSPIKING O.I.07F05~03~02~OIF007.005.003~002'a.OOIeT.0-45.0-<O30"420-4+e~OI.0-45o~F0-505.0-53'-52'-SI'-5CVY)IAh.~~~0OOO00OQ0CVAIllhQCladDamage(5)FIGURE10RELATIONSHIPOF5CLADDAMAGEWITHXCOREINVENTORYRELEASEDOF1-132 1~0.70.50.3020~1~07~05~03~02~01F007005003s0020F0017.O-C5'"I5o3.0-42'-4r~qSg<~rqO~rgO1'"47'-55'"53.0-52'"51'"5CV,Yln~~~~~CV6~0h.0O.0Q0O~OJ~~J~OO0OlOh0CladDamage(X)FIGURE11RELATIONSHIPOFXCLADDAMAGEWITHXCOREINVENTORYRELEASEDOF,I-133 1~0.70.50.30.20~1~07.05F03.02~01.007.005.003I.002o.0017.0-45'-43.0-4S-o2.0-4r'PrregOrrrr1~0-47~0"55~0-5'3.0-52~0-51~0-5rCVY)Nh~~\0~~~~~~yOll9lAh.QQ0QQQoOJt9QoQlhh0CIadDamage(X)FIGURE12RELATIONSHIPOFXCLADDAMAGEWITHXCOREINVENTORYRELEASEDOF1-135 OCl0~0~0~0~~0~0F01F00F00~00:00~0017'"50-argQ~~0)8~a~rQrrgQ3~0-~So2.0->1'"~7'"5~0-3~0"2~0-1~0-CVWV)~~~~hlANNOOOOOOOOOOCVYlV)WOCladDamage(X)FIGURE12RELATIONSHIPOFXCLADDAMAGEWITH~COREINVENTORYRELEASEDOF1-135 100~70'0'0'0'0',53~re(D1CJo0.70~0~0~0~1OOFuelOvertemperature(X)FIGURE13RELATIONSHIPOF~~'UELOVERTEMPERATURE-WITH'XCOREINVENTORYRELEASEDOFXE,KR,I,ORCS 1~0~0~0~0~0.1~0~0~01CC~00SF00F00F00S0F0017~0-5~0-.~gC'rrgO+3~0-2'"1~0-Nh0O0"OlhhQFuelOvertemperature(X)FIGURE14RELATIONSHIPOFXFUELOVERTEMPERATUREWITHXCOREINVENTORYRELEASEOOFBAORSR

)00'0.50'0~20'0'~5~ro+r*y~+rr2~0.7r0.0~0~O.llAh0O0ONhQFuelMelt(5)FIGURE15RELATIONSHIPOF5FUELMELTWITHXCOREINVENTORYRELEASEDOFXE,KR,I,CS,ORTE 100.010.01.00.10.011.010.0fuelMeItP)100.0FIGURE16RELATIONSHIPOFXFUELMELTWITH~oCOREINVENTORYRELEASEDOFBAORSR 100.010.01.00.10.010.0011.010.0FuelMelt(5)100.0FIGURE17RELATIONSHIPOF'X'FUELMELTWITHXCOREINVENTORYRELEASEDOFPR 30..25~20'5~UNIT2UNIT1///aaaaaaaaaaCVEOC)C'.aZIRC-MAl'ERREACt'ONPKRCc.Hf.hGKFIGURE18CONTAINMENTHYDROGENCONCENTRATIONBASEDONZIRCONIUMWATERREACTION 100%NOBLEGASRELEASE52KNOBLEGASRELEAS0.3%NOBLEGASRELEASEANS18.1NORtQLOPERATINGNOBLEGASRELEASE1.010.0100.01000.0TIMEAFTERSHUTDOWN(HOURS)FIGURE19PERCENTNOBLEGASESINCONTAINMENTFORUNIT1ANDUNIT2 APPENOIX8 EXAMPLEOFCOREDAMAGEASSESSMENTThefollowingexampleis,presentedtoillustratetheuseofthisprocedure.SIMULATEDACCIDENTSCENARIOForthisexample,Unit1hasexperiencedanaccidentwheretheplant'smonitoringsystemsindicatedthatsafetyinjectionhadinitiatedandasignificantamountofwaterhadaccumulatedinthecontainment.Sampleswereavailablefromtheprimarycoolant(hotleg),thecontainmentsump,andthecontainmentatmosphere.NUCLIDESAMPLINGSampleswerecounted6hoursafterreactorshutdown.TheresultsofthesamplecountsarepresentedinTables3A,38,and3C.Allsampleactivitiesreportedrepresenttheactivityofthesampleatthetimeofanalysisandhavenotundergoneadecaycorrectionbacktotimeofshutdown.ThedecaycorrectionfactorsaredeterminedfromTable4andrecordedinTables3A,3B,and3C.Thecorrectedsampleactivitiesarethendeterminedbymultiplyingthesampleactivitybythecorrectionfactor.ThecorrectedsampleactivitiesarerecordedinTables3A,3B,and3C.LIUIDMASSTable5wascompletedtodeterminetotalliquidmassavailablefordistributionintheRCSandcontainment.All4accumulatorshaddischarged,theRNSThadsupplied350,000gallons,andtheboroninjectiontank(900gallons)haddepleted..Also,itisassumedthatalloftheicehadmeltedsupplying2.7x10ibmofwater.Atotalwatermassof2.91x10gram69wascalculated.Atthetimeofsampling,theRCStemperaturewas350'F,andthecontainmentwatertemperatturewas150'F.Thereactorvessellevelindicationsystemwasnotfunctioningproperlyattimeofsampling,andnoindicationwasabletobe recorded.Assuch,thecontainmentwaterwasthendetermined.Thecontainmentsumplevelindicatedthesumpwasfullwhilethecontainmentlevelindicatedan87'Xheight.rReferringtoFigure3,87percentcorrespondstoarangeofpossiblevolumesforthecontainment.Acontainmentwatervolumeof98,000ftwasthenestimatedbytakingtheaverageoftherange;98,0003ftofcontainmentwaterat1504Fcorrespondsto2.77x10grams.398Subtractingthisfromthetotalwatermass,aRCSwatermassof1.4x10gramswasdetermined.TheRCSandcontainmentwatermasseswererecordedinTable3Aand38,respectively.TOTALACTIVITYRELEASEDThetotalactivityreleasedofeachnuclideforeachsamplelocationwasthencalculatedbymultiplyingthecorrectedsampleactivitybythewatermassorcontainmentvolumeandrecordedinTables3A,38,and3C.ThesevalueswereagainrecordedinTable7A.ThetotalactivityofeachnuclidewascalculatedbysummingtheactivityforeachsamplelocationandwasrecordedinTable7A.TOTALCOREINVENTORYThepowerhistoryforthe30dayspriortoreactorshutdownwasrecordedinTable8.ThepowercorrectionfactorsforKr-87andI-132weredeterminedbythesteady-statepowercorrectionequationFornuclidewithhalf-liveslessthan1day.ThepowercorrectionfactorsforXe-133,I-131,andBa-140weredeterminedbythetransientpowercorrectionfactorfornuclideswithhalf-livesgreaterthan1day.ForCs-137,thetransientpowercorrectionfactoruti.lizingeffectivefullpowerdaysofoperationduringthecyclewasused.Inthisexample,thecorehadoperatedfor240effectivefullpowerdaysduringthe400daysofcycleoperation.ThepowercorrectionfactorforCs-137is240EFPD400DaysThepowercorrectionfactorswererecordedinTable7A.

Thetotalcorrectedinventorywasthencalculatedbymultiplyingtheequilibriumcoreinventory(listedinTable7A)bythepowercorrectionfactor.ThetotalcorrectedcoreinventorywasrecordedinTable7A.ESTIMATIONOFPERCENTFUELOAHAGECompletingTable7A,thepercentageofcorrectedcoreinventoryreleasedofeachnuclidewascalculatedfromthecorrectedactivityreleasedandthecorrectedcoreinventory.ThepercentreleasedforeachnuclidewasusedwiththeappropriategraphsofFigures4through16todeterminethecategoryandestimateofcoredamage.EstimateswereenteredinTable10undertheappropriatecategories.NUCLIOEACTIVITYRATIOSTablellwascompletedtodeterminethenuclideactivityratios.TheratioswerecomparedtothegapandfuelpelletactivityratioslistedinTable11andthenrecordedinTable10undertheappropriatecategories.AUXILIARYINOICATORSItwasdeterminedthatthecorehaduncoveredforapproximately30minutesduringtheaccident.Thecoreexitthermocouplereadingsreached1750'F.ThesevalueswerecomparedwithTable12andrecordedinTable10undertheappropriatecategories.Thecontainmenthydrogenmonitorindicateda4Xhydrogenconcentration,buttheignitorshadinitiatedandsomehydrogenburninghadtakenplace.Thehighrangecontainmentareamonitorindicatedareadingof2.5E4R/hrat6hoursaftertheshutdown.Comparing2.5E4R/hrwithFigure18andTable12,thisvaluewasrecordedinTable10undertheappropriatecategories.

COREOAHAGEASSESSMENTAlldatacollectedinTab)e10wasevaluatedtoestimatetheextentofcoredamage.Thenuclidesanalyzedforthis.assessmentwereKr-87,Xe-133,I-'131,I-132,Cs-137,andBa-140.Thenoblegases,iodine,andcesiumarereleasedduringallstagesofcoredamagewithBa-140beingacharacteristicfissionproductoffuelovertemperatureandfuelmelt.BasedontheBa-140data,thedamagehadprogressedtoapproximately20$fuelovertemperatureandminorfuelmelt(<1$).Thenoblegasandiodinedataindicatedgreaterthan100percentcladdamagehadoccurred.However,itisrecognizedthatinactualitythereisanoverlapbetweentheregimesofcoredamagestates.Thereleaseduetoovertemperaturedominatedthereleaseduetocladdamage,anditisestimatedthatalargeamount{>50%)claddamagehadoccurred.JTheauxiliaryindicatorssupportedtheradionuclideanalysis.Thefactthatthecoreuncoveredandthecoreexitthermocouplesreachedaround1750'Fareindicativethatfuelovertemperaturehadoccurred.Thehydrogenconcentrationof4X,wasinconclusiveduetotheignitorsforcingsomehydrogenburns.However,thefactthattherewasasignificantamountofhydrogenproducedforburningtooccursupportstheassessmentthatthecoreexperiencedcladdamageandfuelovertemperature.Thehighrangecontainmentareamonitorreadingsof3.5E4supportsthelessthan50$fuelovertemperaturedamagestate.Thus,forthisexample,thefinalfueldamageassessmentisgreaterthan50%cladfailure,lessthan50Kfuelovertemperature,andthepossibilityofsomeveryminorfuelmelting(<lA).

TABLE1SELECTENUCLIDESFORCOREDAMAGEASSESSMENTCoreDamageStateNuclideHa1f-Life>PredominantGammasK'evYieldCladFailureFuelOverheatFuelMeltKr-85m>>Kr-87Kr-88>>Xe-131mXe-133Xe-133m>>Xe-135>>I-131I-132I-133I-135Rb-88Cs-134Cs-137Te-129Te-132Sr-89Sr-90>>Ba-140La-140La-142Pr-1444.4h76m2.8h11.8d5.27d2.26d9.14h8.05d2.26h20.36.68h17.8m2yr30,yr68.7m77.7h52.7d28yr12.8d40.22h92.5m17.27m150(74),305(13)403(84),2570(35)191(35),850(23),2400(35)164(2)81(37)233(14)250(91)364(82)773(89),955(22),1400(14)530(90)1140(37),1280(34),1460(12),1720(19)898(13),1863(21)605(98),796(99)662(85)455(15)230(90)(betaemitter)(betaemitter)537(34)487(40),815(19),1596(96)650(48),1910(9),2410(15),2550(11)695(1.5)ValuesobtainedfromTableofIsotoes,Lederer,Hollander,andPerlman,SixthEdition.""Thesenuclidesaremarginalwithrespecttoselectioncriteriafor.candidatenuclides;theyhavebeenincludedonthepossibilitythattheymaybedetectedandthusutilizedinamanneranalogoustothecandidatenuclides.

TABLE2SuestedSamlinLocationsScenarioPrincipalSamlinLocationsOtherSamlinLocationsSmallBreakLOCAReactorPower>lN*ReactorPower<1~+RCSHotLeg,ContainmentAtmosphereRCSHotLegRCSPressurizerRCSPressurizerLargeBreakLOCAReactorPower>1~*ReactorPower<l~+SteamLineBreakContainmentSump,ContainmentAtmosphere,RCSHotLegContainmentSump,ContainmentAtmosphereRCSHotLeg,RCSPressurizerContainmentAtmosphereSteamGeneratorTubeRuptureIndicationofSignifi-cantContainmentSumpInventoryRCSHotLeg,Secondary.SystemContainmentSump,ContainmentAtmosphereContainmentAtmosphereContainmentBuildingRadiationMonitorAlarmSafetyInjectionActuatedContainmentAtmosphere,ContainmentSumpRCSHotLegRCSPressurizerIndicationofHighRadiationLevelinRCSRCSHotLegRCSPressurizerAssumeoperatingatthatlevelforsomeappreciabletime.

TABLE3ARCSACTIVlTYWORKSHEETguJci~eElapseTimeShutdowntoSampleCounttoursHeasuredSpecificActivityDecayCorrectionFactorCorrectedSpecificActivityRCSHassRCSActivity~laSCiKr85mKrB>Kr88Xe131mXe133Xe133mXe1351131T132T133I135Rb88Cs134Cs137Te129Te132Ba140La140La142Pr144/.7(~)/.o(-3)/.DZg.03/.0/~.C)r-V(B)

TABLE38CONTAINHENT,SUHPACTIVITYWORKSHEETucideElapseTimeShutdowntoSampleCountthourHeasuredSpecificActivityOecayCorrectionfactorCorrectedContainmentContainmentSpecificActivityWaterHassWaterActivity~SSCiKr85mKr87Kr88Xe131mXe133Xe133mXe135I131I132I133I135Rb88Cs134Cs131Te129Te132Ba140La140La142Pr144 TABLE3CCOHIAIHHEHTATHOSPIIEREACTIVITYWORKSHEET+decideElapseTimeShutdowntoSampleCountourHeasuredSpecificActivityOecayCorrectionCi/ccFactorCorrectedContainmentContainmentSpecificActivityVolumeActivityCiccCCCiKr85mKr81Kr88Xe131mXe133Xe133mXe135I131I132I133I135Rb88Cs134Cs131Te129Te132Ba140La140La142PrIhl TABLE4DECAYCORRECTIONFACTORŽWITHPARENT-OAUGHTEREFFECTNuclideCorrectionFactorKr85mKr87Kr88Xe131mXe133Xe133mXe135I131I132I133I135Rb88Cs134Cs134Te129Te132Ba140.La140La142Pr1440.158te0.547te'.248te1/-2.66e'3.66e(3'5E)t66(4E3)t1/-0.187e',0.10e'1.287e(-3.41E-2)t(-5.48E-3)t1287{-1.28E-2)t1/-0.10e'l.lie(-3.41E-2)t{-1.28E-2)t1/-9.14e'0.033e+10.17e{104E1)t(267)t1017(758E2)t(3.59E-3)te1/1.03e'0.03e(892'E3)t003(307E1)t(3.41E-2)te0.104te'/110248t-010(234)t1.01~01/1.09e'0.167e-0.257e(0'161)t847E4t-0257(0'605){8.92E-3)te(2.26E-3)te1/1.08e-0.08e(226E}t008(1'7)1/-0.145e'1.145e1/0.909e'0.09le*Time,t,isthenumberofhoursbetweenshutdownandtimeofsamplecount.

TABLE5ESTIMATEOFTOTALLIgUIOHASSl.Estimatethevolumeaddedforthefollowing:Tanka.RefuelingWaterStorageTankb.AccumulatorAc.Accumulator8d.AccumulatorCe.Accumulator0f.BoronInjectionTankg.SprayAdditiveTankh.Othersourcei.MeltedIceEstimatedVolumeAdded3~cocC~,z<3T7Z.CSav9,ps-Z.EstimatedMassAddedQ.7preMaximumVolume~dd372,2507,2637,2637,2637,2639004,000MaximumMassAdded(ibm)2.7xl062.Convertestimated'volumeaddedfromgallonstograms.Addedvolume:,gallonsx3785gms/gal=/-<~~igms3.Converticemeltedmassfromibmtograins2~7x/~~9ibmx454grams/ibm~~+gms4.TheaverageReactorCoolantSystemHassis2.40x10gms.85.OeterminetheTotalLiquid.MassasFollows:5'assadded/-//<~~gms+meltedicemass+RCSmass2.4x10gms=~-9lv/>8gms TABLE6ESTIHATEOF-RCSMATERHASS*ANOCONTAINHENTMATERMASSAYERAGEOPERATINGRCSVOLUHE=11,780ft31.Recordthereactorvessellevel,pressurizerlevel,andRCStemperatureattimewhensamplewastaken.Reactorvessellevel=PressurizerlevelRCStemperatureoFIindice'A0>>s'y'5~.~nq>uori<inaQcao2.OetermineRCSvolumeattimeofsamplebyestimatingfromlevelindicationsthepercentageofwaterintheRCS.ftxf+100=3.OetermineRCSspecificgravityfromFigurel.RCSspecificgravity=4.DetermineRCSmassasfollows:~1.028.3x10cc3RCSvolume(ft)xspecificgravityx'ccft3ftx3xx~1.028.3x10ccccft35.RecordtheContainmentSumplevelindicationandthecontainmentlevelindication.ContainmentSumpLevel=ContainmentLevel/yOS7 TABLE6(Continued)'IESTIMATEOF,RCSWATERMASS~ANQCONTAINMENTWATERMASSAVERAGEOPERATINGRCSVOLUME=11,780ft36.DeterminecontainmentwatervolumefromFigures2and3usingthelevelsfromStep5.Note:IfsumplevelindicatessumpisfulluseFigure3.ContainmentWaterVolume=7.OeterminecontainmentwaterspecificgravityfromFigurel.Containmentwaterspecificactivity=f~oP8.Determinecontainmentwatermassasfollows:3Containmentwatervolumexspecificgravityx'1.0m28.3x10ccccft31.0gm28.3x10cc3x-xCC3ftaZ-77~/5gms*Ifareactorve'ssellevelindicationisnotavailableorisconsiderinaccuratebasedonengineeringjudgmentssubtracttheestimatedcontainmentwatermassfromtheestimatedtotalwatermass(Table5)todetermineRCSwatermass.TotalWaterPass+-~~~~~gms-containmentwatermass~.7><<~gmsRCSmass~-~~~<gms 1AT01ALRELEASEACTIVITY/PERCENTRELEASEO-UNIT1RCSContainmentContainmentTotalEqui)lbr1umCorrectedActlvltySumpActlvltyAtmosphereActlvltyActlvltyCoreInventory*PowerCorrectionCoreInventoryii~uc(Qe~c~cCCIReleasePercentage*tKr85mKR87Xr88Xe131mXe133Xe133mXe135I133I135Rb88Cs134Cs137Te129Te132Ba140La140I.a112Pr144~a(d)ei(c)2.0(7)3.6(7)5.2(7)5.7(5)1.8(8)2.5(7)3.4(7)8.9(7)1.3(8)1.8(8)1.6(8)5.3(7)2.1(7)1.0(7)3.0(7)1.3(8)1.5(8)1.6(8)I.I(8)1.1(8)o.{'.&./7.&"2.0(7)2.0x10.Thisnotationlsusedthroughouttheprocedure.7>>ReleasePercentageTotalActlvltCorrectedCoreInventoryx100 TABLE78TOTALRELEASEACTIVITY/PERCENTRELEASEO-UNIT2RCSActivityg~ucl4~CContainmentSumpActivity~CContainmentAtmosphereActivityciTotalEquilibriumCorrectedActivityCoreInventory*PowerCorrectionCoreInventoryCICiFactorCiReleasePercentage*Kr85mKr87Kr88Xe131mXe133Xe133mXe135I131I132I133I135Rb88Cs134Cs137Te129Te132Ba140La140La142Pr1442.1(7)3.8(7)5.4(7)6.0(5)1.9(8)2.7(7)3.5(7)9.3(7)1.3(8)1.9(8)1.7(8)5.5(7)2.2(7)1.0(7)3.1(7)1.3(8)1.6(8)1.7(8)1.4(8)1.1(8)**ReleasePercentage~TotalActivitCorrectedCoreInventoryx100 TABLE8POWERHISTORYOF30DAYSPRIORTOSHUTDOWNInterval/ZAveragePowerLevel*P)zy37$2$0JC2~ZV37OperatingPeriodatP~t~hoursxZfI'20.PeriodBetweenendoftgandReactorShutdownthours><8/"-/20PowerCorrectionFactorPCF**Stead-StatePowerConditionPCFTransientPowerConditionPCFI.Half-LifeofNuclide<1DaAveraePowerLevelHWtforrior4dasRatedPowerLevel(Hwt)-l.t-X,it'P(1-e)eRatedPowerLevel(HWt)II.Half-LifeofNuclide>1DaAveraePbwerLevelHWtforrior30dasRatedPowerLevel(Hwt)-Xt-)it'P(1-ej~)eRatedPowerLeve](HWt)III.Half-LifeofNuclide-1YearAveraePowerLevelHWtforrior1earRatedPowerLevel(HWt)EffectiveFullPowerDasEFPDTotalCalendarDaysofCycleOperation*AveragePowerLevelisdefinedasthepowerlevelatwhichthepowerleveldoesnotvarymorethan+10percentoftheratedpowerlevelfromthetimeaveragedvalue.**I~=decayconstantinhours1ofeachnuclide.)iofeachnuclideislistedin TABLE9NuclideDECAYCONSTANTS(7ii)OFEACHNUCLIOErHalf-Life-1hoursKr85mKr87Kr88Xe131mXe133Xe133mXe135I131I132I133I135Rb88Cs134Cs137Te129Te132Ba140La140La142Pr1444.4h76m2.8h11.8d5.27d2.26d9.14h8.05d2.26h20.3h6.68h17.8m2yr30yr'8.6m77.7h12.8d40.22h92.5m17.27m0.1580.5470.2482.45(-3)5.48(-3)1.28(-2)7.58(-2)3.59(-3)0.3073.41(-2)0.1042.343.96(-5)2.64(-6)0.6058.92(-3)2.26(-3)1.72(-2)0.4502.41 TABLE10COREDAMAGEASSESSMENTEVALUATIONSHEETIndicatorPercentCladDamaePercentOvertemeraturePercentFuelMelt<50'A>505<505>505<505>50%RadionuclideAnalsisKr85mKr87Kr88Xe131mXe133Xe133mXe135I131I132I135Cs134Cs137-Te129Te132Ba140La140La142Pr144SC+g.gf-edRatiosKr85m/Xe133Kr87/Xe133Kr88/Xe133Xe131m/Xe133~0.2+

TASLE10(Continued)COREDAMAGEASSESSMENTEVALUATIONSHEETIndicatorPercentCladPercentPercentOvertemerature..FuelMelt<50%>50K<50%>50'I<501>50%Ratio(Con't)Xe133m/Xe133Xe135/Xe133I132/I131I133/I131I135/I131AuxiliarIndicatorsCoreUncoveredCoreExitTemp'FContainmentH5Zirc-MaterReaction5IgnitorsOn?HighRangeContainmentMonitorReadingR/hrQE53.XP-Q TABLEllNuclideGapNUCLIDEACTIVITYRATIOSFuelPelletActivitRatioGalculatedActivitRatio"Kr85mKr87Kr88Xe131mXe133Xe133mXe1350.0220.0220.0450.0041.00.0960.0510.110.220.290.0041.00.140.19/.oI131I132I133I1351.00.170.710.391.01.52.11.9/.ONobleGasNuclideReleasedCiXe-133Released(Ci}IodineNuclideReleasedCiI-131Released(Ci)

TABLEe12CHARACTERISTICSOFCATEGORIESOFFUELDAHAGE*CoreDamageIndicatorCoreDamageCategoryPercentandTypeoFFissionProductsReleasedFissionProductRatioContainmentRadlogasHonltor(R/hr)CoreExitThermocouplasReadings(DegF)CoreUncoveryIndicationHydrogenHonltor(VolIIH2)"**6PlantTypeHocladdamage0-50%claddamage50-100Xcladdamage0-50%fuelpelletovertemperature50-IDOLfuelpelletovertemperature0-50XFuelmelt50-100XfuelmeltKr-87<lxl03Xe-133<lxlO31-131<lx103l-133<lxl03Kt-87103-0.01Xe-133103-O.lI"131103-0.31-133103-0.1KI-870.01-0.02Xe-1330.1-0;21-1310.3-0.51-1330.)~-0.2Xe-Kr,Cs,l1-20Sr-Ba0-0.1Xe-Kr,Cs,I20-40Sr-Ba0.1-0.2Xe,Kr,Cs,l40-70Sr-Ba0.2-0.8Pr0.1-0.8Xe,Kr,Cs,l,Te>70SrBa>24Pr>0.8HotApplicableKr-870.0221-133~0.71Kl'-87~0.0221-1330.71Kr-870.221-1332.1Kr-87-0.221-1332.1Kr-870.22I-1332.1Kr-870.22I-1332.10-/E~/gz-/s'E3/.SEEK><Mf,or='V-Z.s/sz.s~-P.mEW)3.$E5<750750-13001300-1650>1650>1650>1650>1650HouncoveryCoreuncoveryCoreuncoveryCoreuncoveryCoreuncovaryCoreuncoveryCoreuncoveryHag1iglble0-)313-2i13-2i13-2I73-2113-2I*Thistablelsintendedtosupplementthemethodologyoutlinedconsiderableengineering)udgement.***lgnltorsmayobviatethesevalues.Xe-133'-131lnthisreportandshouldnotbeusedIIlthoutreferringtothisreportandwithout/p'75jokers077prrg~ado~.>rz.

800.600.500'00'00200'/nSTPFIGURE1-WATEROEiNSITYRATIO(TEMPERATUREVS.STP) 90'0'5CDUJCDCDCI60'0-<0..30'0~i0.CDCDIC1CD41CDCDCDCDCDCClVOLUHE.Fl'3FIGURE2SUMPWATERVOLUMEVERSUSSUMPLEVELINDICATION 90..80..70'0'0~40,30'0'lOO'OClOCIOO0OOOOC7OOOOOOOOOAlET@ORE3'ONTAINMENTWATERYOLUMEYERSUSCONTATNMENTLEVEL.INOICATION 0~~0~0~0~0F01F00F00F00.00QJPg.00r.0-5.0-o+Jc3.0-Cl2'ICPSo1.0i7+05.0-gQrg(08.o+rr~q8r3.0"2-0"1'"tlath,~~~~~~yC4Y)IOhooQoQ.~ooCVPl~~OQQlAhQCladDamage(<)FIGOREGRELATIPNGHIPOFgCLAOOANAGEWITHXCOREINVENTORY.RELEASEDOFKR-87 F70-0-0-0~tF07~0OlClQJ~0ClCC~0O070F007O'00rrgoF00F001CVF7aoa.a~I~hlY)IAha'00Olk1VlQ00Clad.Damage(5)FIGURE7RELATIONSHIPOFXCLADDAMAGEWITH'XCOREINVENTORY--'RELEASEDOFXE-133 I~0.70.50.3020'F07.05.03.02~4Q.r01.007.005.003.002~gQ~O+rIgF001e~7.0"4cc5.0-43.0-420"0I~0"47.0"55.0"53'.0"52.0-51.0"5COQ7~~~~~~~~~CVY)N60eaaoCladDamage(%%d)OOO0OOlP)V)hDFIGUREGRELATIONSHIPOFXCLADDAMAGEWITHSCOREIN~ENTOR"RELEASEDOFI-131 0.~0~0~0F00.00F00F00'0007.0"Ol5.0-<0E.0-2~0-CPI01~0-7'"5.0-r~~r+rgQ~Og3~0-2~0-t0-hlP)Vli&~~0000C4PlVlh0CladDamage(X)00000CV.)Ah0FIGURE10RELATIONSHIPOFWCLADDAMAGENITHMCOREINVENTORYRELEASEDOFI-132 70.50'020-10'.5.3~r~4rrrr2~00~0~0~0~FuelOvertemperature(5)FIGUREZ3:RELATIONSHIPOF5FUELOVERTEMPERATUREMITH'ACOREINVENTORYRELEASEOOFXE,KR,I,ORCS 1~0-00~0~0'~0~0~0QJrF01F00SF00ClF00.00SO.001T.0-5'"~r.@grgo+3'.0"2.0"1~0-LAhOOAfOPlOOOv7hOFuelOvertemperature(5)FIGURE14RELATIONSHIPOFSFUELOVERTEMPERATUREWITHXCOREINVENTORYRELEASEOOFBAORSR 10070-50'0'0~10'~3~2~ro+rprrrr0'0.0~0.0~1nsaOOOIllOOO'uelMelt(X)FIGUREIS,RELATIONSHIPOF'5FUELMELTNITHSCOREINVENTORYRELEASEDOFXE,.KR,I,CS,ORTE 0

100.010.00.10.011.0100'ueIMeIt.(5)100.0FIGURE'GiRELATIONSHIPOFEFUELMELTNITHSCOREINVENTORYRELEASED.OFBAORSR JO.25~20"UNITia~UNIT5.C7C00C)OOC7OlYlVlCCIZlRC-QAI'P3RE.BIGS'ION1'KRCEHf.WGKFIGDREIBCONTAINMENTHYDROGENCONCENTRATIONBASEDON'Z)RCONIUNMATERREACTION l005.NOBLEGASRELEASES2XNOBLEGAS;RELEAS0.3$NOBLEGASRELEASEANS.181NORMALOPERATINGNOBLE'ASRELEASE'0..0..100.01000.0TINEAFTERSHUTOOMN(HOURS)FIGUREZG-PERCENTNOBLEGASES'NCONTAINMENT-.-FOR.UNIT.1ANOUNITP'