ML17326B152

Post-Accident Core Damage Assessment Methodology.

ML17326B152
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Issue date:	08/31/1984
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D.C.COOKPOSTACCIDENTCOREDAMAGEASSESSMENT METHODOLOGY 840SO50aSO 84083iI!'"PDRADOCK050003i5'

',,',',PDRAugust,1984

NOTICE~~~TheD.C.CookPostAccidentCoreDamageAssessment Methodology ReportconsistsofusingtheWestinghouse Owner'sGroupRevision1genericreportandmodifying ittoincluderelevant0.C.Cookplantspecificparameters.

Whereachangeinthetextofthegenericreporthasbeenmadetoincorporate plantspecificinformation,

brackets, t'],havebeenusedtoindicatethechange.Inthegenericreportthelastsectionconsisted ofastep-by-step exampleontheuseofthecoredamageassessment methodology.

Inthisreporttheexamplesectionisreplacedwithaprocedure specificto0.C.Cook.Alsoincludedisanexampleofthisprocedure.

TABLEOFCONTENTSINTRODUCTION ANDPURPOSE1.1Methodology

2.0 TECHNICAL

BASISFORCOREDAMAGEASSESSMENT METHODOLOGY 2.1Characteristic FissionProducts2.22.3CoreInventories PowerCorrection forCoreInventories 2.3.1PowerCorrection Factor2.4Relationship ofCladDamageWithActivity2.4.1GapInventory 02.4.2SpikingPhenomena 2.4.3ActivityAssociated WithCladDamage2.4.4GapActivityRatios2.4.5Adjustments toDetermine ActivityReleased2.5Relationship ofFissionProductReleaseWithOvertemperature Conditions 2.6Relationship ofNuclideReleaseWithCoreMeltConditions 2.7Samp1ingLocations71010101326264043463.0AUXILIARY INDICATORS 3.1Containment HydrogenCon'centration 3.2CoreExitTemperatures andReactorVesselWaterLevels3.3Containment Radiation HonitorsandCoreDamage535357604.0GENERALIZED COREDAMAGEASSESSHENT APPROACH655.0'IMITATIONS 6

76.0REFERENCES

69APPENDIXACoreDamageAssessment Procedure APPENDIXBExampleofCoreDamageAssessment Procedure LISTOFTABLESTitle~Pae2-1SelectedNuclidesforCoreDamageAssessment FuelPelletInventory forWestinghouse PlantsGapInventory 2-3-1GapInventory HinimumandHaximum122-42-5ExpectedIodineSpikeNormalOperating ActivityIsotopicActivityRatiosofFuelPelletandGap27Parent-Daughter Relationships 37SourceInventory ofRelatedParentNuclides392-9ExpectedFuelDamageCorrelation withFuelRodTemperature 412-10PercentActivityReleasefor100PercentOvertemperature Conditions 422-11PercentActivityReleasefor100PercentCoreHeltConditions Suggested SamplingLocations 52,3-1AverageContainment VolumeandZirconium Hass56Instantaneous GammaRaySourceStrengths Duetoa100PercentReleaseofNobleGasesatVariousTimesFollowing anAccident61 LISTOFTABLES(continued)

TebleTitle~Pae3-2AInstantaneous GammaRayFluxesDueto1004ReleaseofNobleGasesatVariousTimesFollowing anAccident62Characteristics ofCategories ofFuelDamage66 LISTOFFIGURES~FiureTitle~Pae2-1PowerCorrection FactorforCs-134BasedonAveragePowerDuringOperation 2-2Relationship of5CladDamagewith5CoreInventory ReleasedofXe-133152-3Relationship of5CladDamagewith5CoreInventory ReleasedofI-13116Relationship ofXCladDamagewithXCoreInventory ReleasedofI-131withSpiking172-5Relationship of5CladDamagewith5CoreInventory ReleasedofKr-8718Relationship of5CladDamagewith%CoreInventory ReleasedofXe-131m192-7Relationship ofXCladDamagewithXCoreInventory ReleasedofI-132202-8Relationship of5CladDamagewithACoreInventory ReleasedofI-133212-9Relationship of5CladDamagewith5CoreInventory ReleasedofI-135222-10WaterDensityRatio(Temperature vs.STP)2-10ASumpMaterVolumeVersusSumpLevelIndication 2-10B1Containment WaterVolumeVersusSumpLevelIndication, J35 LISTOFFIGURES(continued)

~FtereTitlePacae2-11Relationship ofgFuelOvertemperature withXCore'nventory ReleasedofXe,Kr,I,orCs2-12Relationship ofXFuelOvertemperature with5CoreInventory ReleasedofBaorSr452-13Relationship ofAFuelHeltwithX,CoreInventory Released4BofXe,Kr,I,Cs,orTe2-14Relationship of%FuelHeltwith5CoreInventory Released49ofBaorSr2-15Relationship ofXFuelHeltwith%CoreInventory Released50ofPr3-1Containment HydrogenConcentration BasedonZirconium WaterReaction55Distribution ofThermocouples andFluxThimblesforUnit158andUnit2PercentNobleGasesinContainment forUnit1andUnit264

1.0INTRODUCTION

ANDPURPOSEInMarch1982theNRCissueda"PostAccidentSamplingGuideforPreparation ofaProcedure toEstimateCoreDamage"asasupplement tothepostaccidentsamplingcriteria, ofNUREG-0737

.Thestatedpurposeofthisguidewas(1)toaidutilities inpreparation ofamethodology forrelatingpostaccidentcoredamagewithmeasurements ofradionuclide concentrations andotherplantindicators.

TheprimaryinterestoftheNRCwas,intheeventofanaccident, tohavesomemeansofrealistically differentiating betweenfourmajorfuelconditions:

nodamage,claddingfailure,fueloverheating, andcoremelt.Themethodology developed isintendedtoenablequalified personnel toprovideanestimateofthisdamage.InordertocomplywiththeNRCrequestforsuchamethodology, Westinghouse, undercontracttotheWestinghouse OwnersGroup(WOG),preparedthegenerictechnical report'.$13)1Thisreportiscognizant ofNRC'sinitialintention.

Additionally, thereportreflectsinputbyNRCandvariousrepresentatives oftheWOGprovidedduringseveralmeetingsheldonthissubjectduringthepastyear.tThisreporthasbeenarrangedtopresentthetechnical basisforthemethodology (Section1through5),andtoprovideaprocedure basedonthismethodology (Appendix A).1.1METHODOLOGY Theapproachutilizedinthismethodology ofcoredamageassessment ismeasurement offissionproductconcentrations intheprimarycoolantsystem,andcontainment whenapplicable, obtainedwiththepostaccidentsamplingsystem.Greaterreleaseoffissionproductsintotheprimarycoolantcanoccurifinsufficient coolingissuppliedtothefuelelements.

Thosefissionproductscontained inthefuelpellet-fuelcladdinginterstices arepresumedtobecompletely releaseduponfailureofcladding.

Additional fissionproductsfromthefuelpelletareassumedtobereleasedduringovertemperature andfuelmeltconditions.

Theseradionuclide measurements,

togetherwithauxiliary readingsofcoreexitthermocouple temperatures, waterlevelwithinthepressurevessel,containment radiation

monitors, andhydrogenproduction areusedtodevelopanestimateofthekindandextentoffueldamage.

2.0 TECHNICAL

BASISFORCOREDAMAGEASSESSMENT METHODOLOGY 2.1CHARACTERISTIC FISSIONPRODUCTSDepending ontheextentofcoredamage,characteristic fissionproductsareexpectedtobereleasedfromthecore.Anevaluation wasconducted toselectthefissionproductisotopeswhichcharacterize amechanism ofreleaserelativetotheextentofcoredamage.Nuclideswereselectedtobeassociated withthecoredamagestatesofcladdamage,fueloverheat, andfuelmelt.Theselection ofnuclidesforthismethodology wasbasedonhalf-life, energy,yield,releasecharacteristics, quantitypresentinthecore,andpracticality ofmeasurement usingstandardgammaspectrometry techniques.

Thenuclidesselectedforthismethodology havesufficient coreinventories andradioactive half-lives toensurethattherewillbesufficient activityfordetection andanalysisofthenuclidesforsometimefollowing anaccident.

Mostofthenuclidesselectedhavehalf-lives whichenablethemtoreachequilibrium quicklywithinthefuelcycle.Thelistofselectednuclidescontainsnuclideswithhalf-lives of1dayorlesswhichareassumed/toreachequilibrium inapproximately 4days.Thesenuclidesareusedtoassesscoredamageforcoresthathavebeenoperational inagivencycleforlessthanamonth.Forcoresthathavebeenoperating formorethanamonth,thelistcontainsnuclideswithhalf-lives greaterthan1daywhichreachequilibtium atsometimeduringthefirstmonthofoperation depending onthehalflifeofthenuclide.BothgroupsofnuclidesareusedtoassesscoredamageForcoresthathavebeenoperational inagivencycleformorethanamonth.Otherfactorsconsidered duringtheselection processweretheenergyandyieldofthenuclidesalongwiththepracticality ofdetecting andanalyzing thenuclides.

Nuclideswerechosenbasedontheirreleasecharacteristics toberepresentative ofthespecificstatesofcoredamage.TheRogovinReport(2)notedthatasthecoreprogressed throughthedamagestatescertainnuclidesassociated witheachdamagestatewouldbereleased.

Thevolatility ofthenuclidesisthebasisfortherelationship betweencertainnuclidesandaparticular coredamagestate.

Alistoftheselectednuclidesforthiscoredamage.assessment methodology isshowninTable2-1.2.2COREINVENTORIES Implementation ofthecoredamageassessment methodology requiresanestimation ofthefissionproductsourceinventory available forrelease.Thefissionproductsourceinventory ofthefuelpelletwascalculated usingtheORIGENcomputercode,basedonathree-region equilibrium cyclecoreatend-of-life.

Thethreeregionswereassumedtohaveoperatedfor300,600,and900effective fullpowerdays,respectively.

Foruseinthismethodology thefissionproductinventory isassumedtobeevenlydistributed throughout thecore.Assuch,thefissionproductinventory canbeapplicable tootherequilibrium coreswithdifferent regionalcharacteristics.

Thefuelpelletinventory oftheselectedfissionproductsandsomeadditional fissionproductsofinterestfor0.C.CookUnit1andUnit2isshowninTable2-2.2.3POWERCORRECTION FORCOREINVENTORIES Thesourceinventory showninTable2-2presentsinventories foranequilibrium, end-of-life corethathasbeenoperatedat100percentpower.Forthismethodology asourceinventory atthetimeofanaccidentthataccountsforthepowerhistoryisneeded.Forthosecaseswherethecorehasreachedequilibrium, aratioofthesteadystatepowerleveltotheratedpowerlevelisapplied.Withintheaccuracyofthismethodology, aperiodoffourhalf-lives ofanuclideissufficient toassumeequilibrium forthatnuclide.Fornuclideswithhalf-lives lessthanonedaythepowerratiobasedonthesteady-state powerlevelofthepriorfourdaystoreactorshutdowncanbeusedtodetermine theinventory.

Touseasimplepowerratiotodetermine theinventories oftheisotopeswithhalf-lives greaterthan1day,thecoreshouldhaveoperatedataconstantpowerforatleast30dayspriortoreactorshutdown.

Theassumption ismadethatconstantpowerexistswhenthepowerleveldoesnotvarymorethan+10percentoftheratedpowerlevelfromthetimeaveragedvalue.Fortransient powerhistories whereasteadystatepowercondition hasnotbeenobtained, apowercorrection factorhasbeendeveloped tocalculate thesourceinventory atthetimeoftheaccident.

TABLE2-1SELECTEDNUCLIDESFORCOREDAMAGEASSESSHENT CoreDamageStateNuclideHalf-Life"Predominant GammasKevYield5*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.*"Thesenuclidesaremarginalwithrespecttoselection criteriaforcandidate nuclides; theyhavebeenincludedonthepossibility thattheymaybedetectedandthusutilizedinamanneranalogous tothecandidate nuc1ides.

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)Inventory basedonORIGENrunforequilibrium, end-of-life core.*"1.2(7)=1.2x107.Thisnotationisusedthroughout thisreport.

Thereareafewselectednuclideswithhalf-lives aroundoneyearorlongerwhichinmostinstances donotreachequilibrium duringthelifeofthecore.Forthesefewnuclidesaqdwithintheaccuracyofthemethodology, apowercorrection factorwhichcomparestheeffective fullpowerdaysofthecoretothetotalnumberofcalendardaysofcycleoperation ofthecoreisapplied.Ouetotheproduction characteristics of,cesium-134, specialconsideration mustbeusedtodetermine thepowercorrection factorforCs-134.Thispowercorrection factorcanbeobtainedfromFigure2-1.J2.3.1POWERCORRECTION FACTORA)Steadystatepowerpriortoshutdown.

1)Half-life ofnuclide<1dayAveraePowerLevelMwtforrior4dasPowerCorrection Factor=RatedPowerLevel(Mwt)2)Half-life ofnuclide>1dayAveraePowerLevelMwtforrior30dasPowerCorrection Factor=RatedPowerLevel(Mwt)3)Halflifeofnuclide=1yearAveraePowerLevelMwtforrior1earPowerCorrection Factor=RatedPowerLevel(Mwt)Steadystatepowercondition isassumedwherethepowerdoesnotvarybymorethan+10percentofratedpowerlevelfromtimeaveragedvalue.8)Transient powerhistoryinwhichthepowerhasnotremainedconstantpriortoreactorshutdown.

Forthemajorityoftheselectednuclides, the30-daypowerhistorypriortoshutdownissufficient tocalculate apowercorrection factor.

1.00.990KPOWER0.8iERCORRECTION FACTOR75KPOWER0.60.50.40.30.20.10.02004006008001000CYCLEOPERATION (CALENDAR

.DAYS)FIGURE2-1POWERCORRECTION FACTORFORCS-134BASEDONAVERAGEPOWERDURINGOPERATION PowerCorrection Factor=where:-X.t-Kit'P(1ej)eEtRP(1-ej)pjRPtjaveragepowerlevel(Nwt)duringoperating periodt.jratepowerlevelofthecore(Mwt)operating periodindaysatpowerPwherepowerdoesnotvarymorethan+10percentpowerofratedpowerlevelfromtimeaveragedvalue(P)decayconstantofnuclideiininversedays.timebetweenendofperiodjandtimeofreactorshutdownindays.Ifthetotalperiodofoperation isgreaterthanfourhalf-lives ofthenuclidebeingconsidered, thepowercorrection isasfollows.Thisiswithintheaccuracyofthismethodology.

gt>4x0.693PowerCorrection Factor=-kit-'k.t'.EP.(1-ej)eRPForthefewnuclideswithhalf-lives aroundoneyearorlonger,apowercorrection factorwhichratioseffective fullpowerdaystototalcalendardaysofcycleoperation isapplied.EFPOPowerCorrection Factor=totalcalendardaysofcycleoperation C)ForCs-134Figure2-1isusedtodetermine thepowercorrection factor.TouseFigure2-1,theaveragepowerduringtheentireoperating periodisrequired.

2.4RELATIONSHIP OFCLAOOAHAGEMITHACTIVITY2.4.1GAPINVENTORY Duringoperation, volatilefissionproductscollectinthegap.Thesefissionproductsareisotopesofthenoblegasesandiodine.(4)Todetermine thefissionproductinventory ofthegap,theANS5.4Standardformulaewereusedwiththeaveragetemperature andburnupofthefuelrod.Theaveragegapinventory fortheentirecoreforthismethodology wasestimated byassumingthecoreisdividedintothreeregions-alowburnupregion,amiddleburnupregion,andahighburnupregion.UsingtheANS5.4Standard, thegapfractionandsubsequent gapinventory werecalculated foreachregion.Eachregionisassumedtorepresent one-third ofthecore.Thetotalgapinventory wasthencalculated bysummingthegapinventory ofeachregion.Forthepurposesofthiscoredamageassessment methodology, thisgapinventory isassumedtobeevenlydistributed throughout

.thecore.Table2-3showsthecalculated gapinventories forUnit1andUnit2ofthenoblegasesandiodines.Table2-3-1showstheminimumandmaximumgapinventories.

Theminimumandmaximumgapinventory weredetermined byassumingtheentirecorewasoperating atthelowburnupcondition andthehigh'burnup conditions, respectively.

2.4.2SPIKINGPHENOMENA Reactorcoolantsystempressure, temperature, andpowertransients mayresultiniodinespiking.(Cesiumspikingmayalsooccurbutisnotconsidered inthismethodology.)

Spikingisnotedbyanincreaseinreactorcoolantiodineconcentrations duringsometimeperiodafterthetransient.

Inmostcases,the'iodineconcentration wouldreturntonormaloperating activityataratebasedon'the'systempurification

'hal'f-.life

'Spikin'g is'characteristic of-"-".thecondition whereanincreasein'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)Totalcoreinventory basedon3regionequilibrium coreatend-of-life.

Gapinventory basedonANS5.4Standard.

• "Additional nuclides; nographsprovided.

11 TABLE2-,3-1GAPINVENTORY MINIHUMANOHAXIHUMGapInventory, 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)

• Additional nuclides; nographsprovided.

• • Minimumvaluesarebasedonthelowburnupregion(5,000HWO/HTU).

Haximumvaluesarebasedonthehighburnupregion(25,000HWD/HTU).

12 Forthismethodology consideration ofthespikingphenomena intotheradionuclide analysisislimitedtotheI-131information foundinWCAP-9964'.

WCAP9964,presents releasesinCuriesofI-131duetoa(5)transient whichresultsinspikingbasedonthenormalprimarycoolantactivityofthenuclides.

TheWCAPgivesanaveragereleaseand90percentconfidence interval.

Thesevaluesarepresented inTable2-4.'Theuseofthisdataisdemonstrated inSection2.4.3.2.2.4.3ACTIVITYASSOCIATED WITHCLADDAMAGECladdamageischaracterized bythereleaseofthefissionproductswhichhaveaccumulated inthegapduringtheoperation oftheplant.Thecladdingmayruptureduringanaccidentwhenheattransferfromthecladdingtotheprimarycoolanthasbeenhinderedandthecladdingtemperature increases.

Claddingfailureisanticipated inthetemperature rangeof1300to2000'Fdepending upontheconditions ofthefissionproductgasandtheprimarysystempressure.

Claddamagecanbegintooccurinregionsofhighfuelrodpeakcladtemperature basedontheradialandaxialpowerdistribution.

Astheaccidentprogresses andisnotmitigated, otherregionsofthecoreareexpectedtoexperience hightemperatures andpossiblycladfailure.Whenthecladdingruptures, itisassumedthatthefissionproductgapinventory ofthedamagedfuelrodsisinstantaneously releasedtotheprimarysystem.Forthismethodology itisassumedthatthenoblegaseswillescapethroughthebreakoftheprimarysystemboundarytothecontainment atmosphere andtheiodineswillstayinsolutionandtravelwiththeprimarysystemwaterduringtheaccident.

Todetermine anapproximation oftheextentofcladdamage,thetotalactivityofafissionproductreleasediscomparedtothetotalsourceinventory ofthefissionproductatreactorshutdown.

Includedinthemeasuredquantityofthetotalactivityreleasedisacontribution fromthenormaloperating activityofthenuclide.Anadjustment shouldbemadetothemeasuredquantityofreleasetoaccountforthenormaloperating activity.

Directcorrelations canthenbedeveloped whichdescribetherelationship betweenthepercentage oftotalsourceinventory releasedandtheextentofcladdamageforeachnuclide.Figures2-2through2-9presentthedirectcorrelations foreachnuclideingraphical form.Thecontribution ofthenormaloperating activity13 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<0.0013400380200200100100290/90UerConfidence LevelCi/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*SAisthenormaloperating I-131specificactivity(yCi/gm)intheprimarycoolant.

0'g0~0.0'F070CJtt$C)~0CY~0OCJc~01007OF00r~0)qadiu9o+00F00.001OOOOhlY)IAhOOOOOOeunnnOCladDamage(';.')FIGURE2-2RELATIONSHIP OF,'4CLADDAMAGEWITHXCOREINVENTORY RELEASEDOFXE-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(/)FIGURE2-3RELATIONSHIP OF/oCLADDAMAGEWITHXCOREINVEilTORY RELEASEDOFI-131 1~0'0'0'0'F1F07F05~03~02aClF007005e.003C~002O~0017'-45'-43'-42'-4rr'br+rgC~gQrrrr1'-4CVWV)OOOOIAhO~OOOOOhlY)VlhOCladDamageP)FIGUREZ-4RELATIONSHIP OF5CLADDAMAGEWITH5COREINVENTORY RELEASEDQFI-131WITHSPIKING 0~~0~01F00F00F00.000017~0-o50-Oc3~0-Cl2'"dJ51~0-7'"5'"gQrroqr3~0-1'"AlN"IAW~~~CVP)llewhOO0000Q00QCV~U1WClCladDamage(i.)FIGURE2-5RELATIONSHIP OF/CLADDAMAGEMITH~~COREINVENTORY RELEASEDOFKR-87 0'0~0~F107Ie0(YO~0~).0o~01F00?qOr.'>%rrgurquu9ioF00F00~001CV&Ill~~~~CVY)IAbddddddddddCVnv)n.dCladDamage(5)FIGURE2-6RELATIONSHIP OF5CLADDAMAGEWITH5COREINVENTORY RELEASEDOFXE-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-7RELATIONSHIP OFXCLADDAt1AGEWITHX,COREINVENTORY RELEASEDOFI-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)FIGURE2-8RELATIONSHIP OF'XCLADDAMAGEWITHgCOREINVENTORY RELEASEDOFI-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)FIGURE2-9RELATIONSHIP OF,oCLADDAMAGE.WITHNCOREINVENTORY RELEASEDOFI-135 hasbeenfactoredintothecorrelations showninFigures2-2through2-9.Examplesofhowtoconstruct thecorrelations showninFigures2-2through2-4arepresented inthenext,twosections.

Figures2-5through2-9weredetermined inthesamefashionasdescribed intheexamples.

ItshouldbenotedthatnotallofthefissionproductslistedinTable2-3needtobeanalyzedbutasmanyaspossibleshouldbeanalyzedtodetermine areasonable approximation ofcladdamage.2.4.3.1Xe-133Agraphical representation canbedeveloped whichdescribes thelinearrelationship ofthemeasuredreleasepercentage ofXe-133totheextentofcladdamage.Sincethelinearrelationship isbasedonpercentage ofinventory

released, thelinearrelationship appliestoallMestinghouse standardplants.TheWestinghouse 3-Loopplantisusedasthebaseplantfordeveloping therelation.

Thetotalsourceinpentory ofXe-133ForaWestinghouse 3-Loopplantis1.6x10Curies[j.For100percentclad8.(13)ldamageallofthegapinventory, whichcorresponds to1.43x105Curie]wouldbereleased.

For0.1percentcladdamage,1.43x10(13)12Curieswouldbereleased.

Thesetwovaluescanbeusedtorepresent twopointsofthelinearrelationship betweenpercentage oftotalinventory releasedandtheextentofcladdamage.However,thenormaloperating activityneedstobeaccounted intotherelation.

FromTable2-5thenormaloperating activityofXe-133is18pCi/gm.Theaverageprimarycoolant(6)massofa3-Loopplantis1.78x10grams.Thetotalnormaloperating 8contribution tothetotalreleaseofXe-133is3200Curies.Thustheadjustedreleasesare3340Curiesand1.46x10Curiesfor0.1percentcladdamage5-3and100percentcladdamage,respectively.

Thiscorresponds to2.2x10-2percentfor0.1percentcladdamageand9.1x10for100percentcladdamage.This'elation isshowninFigure2-2.Figure2-2alsoshowsaminimumandamaximumrelationwhichboundthebestestimateline.Theminimumandmaximumlinesweredetermined byboundingthefissionproductgapinventory.

Theminimumgapinventory wasdetermined byassumingtheentirecorewasoperating atthelowburnupcondition usedtocalculate theaveragegapinventory asdescribed inSection2.4.1.The23 TABLE2-5NORMALOPERATING ACTIVITY~

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 maximumgapinventory wasdetermined byassumingtheentirecorewasoperating atthehighburnupcondition ofSection2.4.1.Forthe3-Loopplant,theminimumgapinventory foreXe-133is2.71x10Ci,andthemaximumvalueis3.67x10Ci'.Thenormaloperating activityisboundedbyassuminga5(13)watermassof1.23x10grams(2-Loopplant)fortheminimumvalueand2.68x10grams(4-Loopplant)Forthemaximumv'alue.Thepointsoftheminimumandmaximumlinearrelations arecalculated inthesamemannerasdiscussed above.2.4.3.2I-131Thegainventory foraWestinghouse 3-LoopplantforI-131is2.3lxl05Curie'j.Theminimumandmaximumgapinventory fora3-Loopplantfor(13)lI-131is4.38xl0Ciand5.98xl0Ci,respectively j.Thesource45lil3)l~(13)linventory ofI-131fora3-Loopplantis8.0x10Curiesg.Thenormaloperating specificactivityforI-131fromTable2-5is0.27yCi/gm.Withaprimary.coolantmassof1.78x10gmforastandard3-Loopplant,the8normaloperating activityofI-131is48Curies.Thepointsoftheaverage,minimum,andmaximumrelations arecalculated inthesamemannerasdescribed inSection2.4.3.1.Figure2-3showsthepercentage ofI-131activityasafunctionofcladdamage.Thepercentage releaseofI-131calculated fromtheradionuclide analysiswouldbecomparedtoFigure2-3toestimatetheextentofcladdamage.ForI-131,thepossibility ofiodinespikingshouldbeconsidered whendistinguishing betweennocladdamageandminorcladdamage.Thecontribution ofiodinespikingisdiscussed inSection2.4.2andisestimated tobeasmuchas950CuriesofI-131releasedtoprimarysystemwithanaveragereleaseof350Curiesbasedonanormaloperating I-131activityof0.27yCipergram'.Thelinearrelationships ofFigure2-3areadjustedtoaccountfor(6)thereleaseduetoiodinespikingbyadding950'CuriesofI-131tothemaximumreleaseandbyadding350CuriesofI-131totheminimumandaveragerelease.Figure2-4showsthepercentage ofI-131releasedwithiodinespikingversuscladdamage.Iodinespikingwasnotconsidered duringthecalculations ofthecorrelations fortheremaining iodines,I-132,I-133,andI-135,Figures2-7through2-9,respectively.

25 2.4.4GAPACTIVITYRATIOSOnceequilibrium conditipns arereachedforthenuclidesduringoperation, afixedinventory ofthenuclidesexistswithinthefuelrod.Forthesenuclideswhichreachequilibrium, theirrelativeratioswithinthefuelpelletcanbeconsidered aconstant.

Equilibrium conditions canalsobeconsidered toexistinthefuelrodgap.Underthiscondition thegapinventory ofthenuclidesisfixed.Thedistribution ofthenuclidesinthegaparenotinthesameproportion asthefuelpelletinventory sincethemigration ofeachnuclideintothegapisdependent onitsparticular diffusion rate.Sincetherelativediffusion ratesofthesenuclidesundervariousoperating conditions areapproximately

constant, therelativeratiosofthenuclidesinthegapareknown.Inthepresenceofotherindicators ofamajorrelease,therelativeratiosofthenuclidescanbecomparedwiththerelativeratiosofthenuclidesanalyzed(corrected toshutdown) duringanaccidenttodetermine thesourceofthefissionproductrelease.Table2-6presentstherelativeactivityratiosforboththefuelpelletandthegap.Therelativeratiosforgapactivities aresignificantly lowerthanthefuelpelletactivityratios.Measuredrelativeratiosgreaterthangapactivityratiosareindicative ofmoreseverefailures, e.g.,fueloverheat.

2.4.5ADJUSTMENTS TODETERMINE ACTIVITYRELEASEDWhenanalyzing asampleforthepresenceofnuclides, theisotopicconcentration ofthesamplemediumisexpressed asthespecificactivityofthesampleineitherCuriespergramofliquidorCuriespercubiccentimeter ofatmosphere.

Thespecificactivityofthesampleshouldthenbeadjustedtodetermine thetotalactivityofthatmedium.Themeasuredactivityofthesampleneedstobeadjustedtoaccountforthedecayfromthetimethesamplewasanalyzedtothetimeofreactorshutdownandadjustedtoaccountforpressureandtemperature difference ofthesamplerelativetotemperature and26 RTABLE2-6ISOTOPICr ACTIVITYRATIOSOFFUELPELLETANDGAPNuclideFuelPelletActivitRatioGaActivitRatioKr-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-133Inventory IodineRatiIodineIsotoeInventorI-131Inventory "Themeasuredratiosofvariousnuclidesfoundinreactorcoolantduringnormaloperation isafunctionoftheamountof"tramp"uraniumonfuelrodcladding, thenumberandsizeof"defects" (i.e."pinholes"),andthelocationofthefuelrodscontaining thedefectsinthecore.Theratiosderivedinthisreportarebasedoncalculated valuesofrelativeconcentrations inthefuelorinthegap.Theuseofthesepresentratiosforpostaccidentdamageassessment isrestricted toanattempttodifferentiate betweenfuelovertemperature conditions andfuelcladdingfailureconditions.

Thustheratiosderivedherearenotrelatedtofueldefectlevelsincurredduringnormaloperation.

27 pressureconditions ofthemedium.Alsothemass(liquid)orvolume(gas)ofthesamplemediumisrequiredtocalculate theisotopicactivityofthatmedium.Thefollowing syctionsdiscusstherequiredadjustments.

2.4.5.lDILUTIONOFSAMPLEMEDIUMThedistribution ofthetotalwaterinventory shouldbeknowntodetermine thewateramountthatisassociated witheachsamplemedium.Ifasampleistakenfromtheprimarysystem,anapproximation oftheamountofwaterintheprimarysystemisneededandasimilarapproximation isrequiredforasumpsample.Forthepurposesofthismethodology thewaterisassumedtobedistributed withintheprimarysystemandthesump.However,consideration shouldbetakenifasignificant primarysystemtosecondary systemleak'rateisnotedasinthecaseofasteamgenerator tuberupture.Theamountofwaterthatisavailable fordistribution istheinitialamountofprimarysystemwaterandtheamountofwaterthathasbeendischarged fromtheRefueling WaterStorageTank(RWST).Also,anadjustment mustbemadeforwateraddedviathecontainment spraysystems,accumulators, chemicaladditiontanks,andicecondensers.

Toapproximate thedistribution ofwater,themonitoring systemsofthereactorvessel,pressurizer, sump,andRWSTcanbeemployed.

Ifnotallofthemonitoring systemsareavailable, themonitoring systemswhichareworkingcanbeusedbyassumingthatthetotalwaterinventory isdistributed inthesumpandtheprimarysystemwithconsideration givenifasignificant primarysystemtosecondary systemleakrateisnoted.Theapproximate totalactivityoftheliquidsamplescanthenbecalculated.

iTheD.C.CookUnitlandUnit2containments areeachequippedwithice6condensers.

Eachcontainment housesapproximately 2.7x10poundsofice,whichprovidesanadditional sourceofwater.TheRWSTcanprovideuptoapproximately 350,000gallonsofemergency corecoolingwaterduringanaccident.

The4accumulators areeachequippedtoprovideapproximately 950ftofwater.Theboronln]ection tankcansupplyg00gallonsofwater.I3RCSactivity(Curies)=SpecificActivity(Ci/ccorCi/gm)xRCSwatervolumeormass(ccorgm).28 Sumpactivity(Curies)=SpecificActivity(Ci/ccorCi/gm)xSumpwatervolumeormass(ccorgm).rTotalwateractivity=RCSactivity+Sumpactivity+ActivityleakedtoSecondary System+Activities fromothersources(accumulators, icecondensers, sprayadditivetanks,etc.).Note:Thespecificactivities shouldbedecaycorrected toreactorshutdown, andtheRCSamountshouldbecorrected toaccountfortemperature andpressuredifferences betweensampleandRGBThecontainment atmosphere activitycanthenbeaddedtoapproximate thetotalactivityreleasedattimeofaccident.

TotalActivityReleased=TotalMaterActivity+Containment Atmosphere Activity2.4.5.2PRESSUREANDTEMPERATURE ADJUSTMENT Themeasurements forthecontainment atmosphere samplesneedtobeadjustedifthepressureandtemperature ofthesamplesatthetimeofanalysisaredifferent thantheconditions ofcontainment atmosphere.

Theadjustments tothespecificactivityandthecontainment volumeareasfollows.P2Tl+460SpecificActivity(Atmosphere)

=SpecificActivity(Sample)x-x(460)'1'2+where:Tl'lT2,P2measuredsampletemperature

('F)andpressure(psia)containment atmosphere temperature

('F)andpressure(psia).PT+460Corrected Containment Volume=Containment FreeVolume(SCF)xp(T+460)'2'3' where:T2,P2T3,P3containment atmosphere temperature

('F)andpressure(psia)standardtemperature (32'F)andpressure(14.7psia).tTheaboveadjustments arebasedonmolarvolumes.Forsamples'inwhichtheatmosphere sampleisdrawnintoaspecified volumeandtheanalysisisperformed tothisvolume,noadjustments toeitherthesamplespecificactivityorcontainment volumearerequired.

Forthoseplantswit6icecondensers, consideration shouldbegiventoaccountforadecreaseinfreevolumeduetotheicemeltingoccupying aportionofthecontainment volume.iEventhough D.C.Cookisaplantwithicecondensers, noadjustment isneededtothecontainment freevolumeduetotheeffectoftheicemelting.Thelistedcontainment freevolume(1.2x10ft)takesintoaccountthe63presenceofsolidice.Sincethereisnegligible difference betweenthedensities oficeandwater,noadjustment isrequired.j Thetotalactivityreleasedtothecontainment atmosphere isTotalContainment Activity=SpecificActivity(Atmosphere) xCorrected Containment Volumewherethespecificactivity(atmosphere) hasbeendecaycorrected totimeofreactorshutdown.

Thespecificactivityoftheliquidsamplesrequiresnoadjustment ifthespecificactivityisreportedonaper-grambasis(pCi/gm).

Ifthespecificactivityisreportedonaper-volume basis(pCi/cc),

anadjustment isperformed toconverttheper-volume specificactivitytoaper-gramspecificactivity.

Theconversion isperformed forconsistency withlatercalculations.

Ifthetemperature ofthesampleisabove200'F,anadjustment isrequiredtotheconversion.

Inmostcasesthesampletemperature willbe30

below200'Fandnoadjustment isnecessary.

Figure2-10showsarelationofwaterdensityatsometemperature relativetothewaterdensityatstandardtemperature andpressure.

Themassoftheliquidmedium(RCSorsump)canbecalculated fromthevolumeofthemedium.Ifthemedium(RCSorsump)temperature attimeofsampleisabove200'F,anadjustment isrequiredtotheconversion.

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)wherethespecificactivityhasbeendecaycorrected totimeofshutdown.

31 600'00'400CPlQQJ300QJi-200ipp.0~~/pSTPFIGURE2-10WATERDEi'ISITY RATIO(TEMPERATURE VS.STP)32 tThesumpandcontainment watervolumecanbeapproximated fromFigures2-10Aand2-10Bbasedonthereadingsofthewaterlevelindicators ofthesumpandcontainment.

Thereactorvessellevel.indication systemcanbeusedtoapproximate theRCSvolume,asdescribed bythefollowing.'.

Ifthewaterlevelinthereactorvesselindicates the,systemisfull,thenthefullreactorcoolantsystemwatervolumeisused.For.Unit1andUnit2theRCSvolumeofeachisapproximately ll,780ftat570'Fand2250psia.2.Ifthewaterlevelinthereactorvesselisbelowthelowendcapability oftheindicator, theRCSvolumeisunknown.Inthiscase,thesumpsampleshouldbegiven.primaryconcern.3.Ifthereactorvessellevelindication systemisnotworking,then,byknowingthewatersourcesavailable, theothermonitorscanbeusedtoestimatetheRCSvolume.Ifitisknownhowmuchwaterisavailable (volumesofRWST,accumulators, boroninjection tank,andoriginalRCSvolume),thevolumeofthesumpandcontainment waterissubstracted fromtheavailable watervolumetoestimatetheRCSvolume.Alsotobeconsidered asasourceofwateriswaterfromthemeltingice.Anassumption canbemadethatalltheicemeltsinapproximately 3.to5hoursafterthestartofanaccident.

2.4.5.3DECAYCORRECTION Thespecificactivityofasampleisdecayadjustedtotimeofreactorshutdownusingthefollowing equation.

SecificactivitmeasuredSpecificactivityatshutdown=tfwhere:radioactive decayconstant,.

l/sectimeperiodfromreactorshutdowntotimeofsampleanalysis, sec.33

'i00.70'O~C5Ul50~ICDQgp30'0'O...VOLUME.FT3FIGURE2-10ASUMPWATERVOLUMEVERSUSSUMPLEVELINDICATION 34 90..80.70'0'DhJ50~C)ICCDClz~0~30'0'0~C)C)ClC)oOOVOLUMEFTClC)C)C)C)C)OoOFIGURE2-108CONTAINMENT WATERVOLUMEVERSUSCONTAINMENT LEVELINDICATION 35 Sincethiscorrection mayalsobeperformed bysomeanalytical equipment, caremustbetakentoavoidduplicate correction.

Also,consideration mustbegiventoaccountforprecursor effectduringthedecayofthenuclide.forthismethodology, onlytheparent-daughter relationships areconsidered.

Table2-7liststhesignificant parent-daughter relationships associated withthemethodology.

Thedecayschemeoftheparent-daughter relationship isdescribed bythefollowing equation.

-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.Sincetheactivityofthedaughteratsampletimeisduetothedecayoftheparentandthedecayofthedaughterinitially releasedatshutdown, anestimation ofthefractionofthemeasuredactivityatsampletimeduetoonlythedecayofdaughterisrequired.

Tousetheaboveequationtodetermine thisfraction, anassumption ismadethatthepercentages ofthesourceinventories oftheparentandthedaughterreleasedattimeofshutdownare36 TABLE2-7PARENT-OAUGHTER RELATIONSHIPS rParentParentHalfLife~~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""Branching decayFactor37 equal(forthenuclidesusedherewithinaFactorof2).Thefollowing stepsshouldbefollowedtocalculate thefractionofthemeasuredactivityduetothedecayofthedaughterthatwasreleasedandthentocalculate theactivityofthedaughterreleasedatshutdown.

1.Calculate thehypothetical daughterconcentration (9)atthetimeofthesampleanalysisassuming100percentreleaseoftheparentanddaughtersourceinventory.

-%At-XBt-Xte-e)+~Bewhere:0')A100%sourceinventory (Ci)ofparent,Table2-2or2-8qo8100Ksourceinventory (Ci)ofdaughter, Table2-2or2-8()8(t)hypothetical daughteractivity(Ci)atsampletimeifparenthas2daughters, Kisthebranching factor,Table2-7'A-1parentdecayconstant, sec-1daughterdecayconstant, sectimeperiodfromshutdowntotimeofsample,sec.2.Oetermine thecontribution ofonlythedecayoftheinitialinventory ofthedaughtertothehypothetical daughteractivityatsampletimeqokBtQB(t)38 TABLE2-8SOURCEINVENTORY OFRELATEDPARENTNUCLIDESNuclideUnit13250HWtUnit23391HWtXe-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.Calculate theamountofthemeasuredsamplespecificactivityassociated withthedecayofthedaughterthatwasreleased.

M=Frxmeasuredspecificactivity(yCi/gmorpCi/cc)B4.Decaycorrectthespecificactivity(M)toreactorshutdown.

MMB-XteB2.5RELATIONSHIP OFFISSIONPROOUCTRELEASEWITHOVERTEMPERATURE CONDITIONS Thecurrentconceptofthemechanisms forfissionproductreleasefromU02fuelunderaccidentconditions hasbeensummarized in2documents, draftNUREG-0956 andIOCORTask11.1('.Thesedocuments describefive(8)principal releasemechanisms; burstrelease,.diffusional releaseofthepellet-to-cladding gapinventory, grainboundaryrelease,diffusion fromtheUOgrains,andreleasefrommoltenmaterial.

Thereleasewhichoccurswhen2thecladdingfails,i.e.,gaprelease,isutilizedtoquantifytheextentofcladfailureasdiscussed inSection2.4.Table2-9presentstheexpectedfueldamagestateassociated withfueTrodtemperatures.

Fissionproductreleaseassociated withovertemperature fuelconditions arisesinitially fromthatportionofthenoblegas,cesiumandiodineinventories thatwaspreviously accumulated ingrainboundaries.

Forhighburnuprods,itisestimated thatapproximately 20percentoftheinitialfuelrodinventory ofnoblegases,cesium,andhalogenswouldbereleased.

Releasefromlowerburnupfuelwouldnodoubtbeless.Following thegrainboundaryrelease,additional diffusional releasefromU02grainsoccurs.Estimates ofthetotalrelease,including UOdiffusional release,varyfrom20to40percent2ofthenoblegas,iodineandcesiuminventories.

Additional information onthereleaseoffissionproductsduring(9)overtemperature conditions wasobtainedfromtheTMIaccident.Inthisinstancecurrentopinionisthatalthoughthecorehadbeenoverheated, fuelmelthadnotoccurred.

Valuesofcoreinventory fractionofvariousfissionproductsreleasedduringtheaccidentaregiveninTable2-10.Thesevalues,40 TABLE2-9EXPECTEDFUELDAMAGECORRELATION WITHFUELRODTEMPERATURE (B)FuelDamaeNoDamage<1300CladDamageBallooning ofzircaloycladdingBurstofzircaloycladdingOxidation ofcladdingandhydrogengeneration 1300-2000>13001300-2000>1600FuelOvertemperature FissionproductfuellatticemobilityGrainboundarydiffusion releaseoffissionproducts2000-34502000-25502450-3450FuelMeltDissolution andliquefaction ofUOintheZircaloy-ZrOeutectic2Meltingofremaining UO2>3450>34505100Thesetemperatures arematerialpropertycharacteristics andarenon-specific withrespecttolocations withinthefueland/orfuelcladding.

TABLE2-10PERCENTACTIVITYRELEASEFOR100PERCENTOVERTEHPERATURE CONOITIONS NuclideMin.*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 derivedfromradiochemical analysisofprimarycoolant,sump,andcontainment gassamples,providemuchgreaterreleasesofthenoblegases,halides,andcesiums,thanisexpected, tobereleasedsolelyfromcladdingfailures.

Inaddition, smallamountsofthemorerefractory

elements, barium-lanthanum, andstrontium werereleased.

Intheparticular caseofTMI,thereleasemechanism, inadditiontodiffusional releasefromgrainboundaries andU02grains,isbelievedtoarisefromU02graingrowthinsteam.Therelationship betweenextentoffueldamageandfissionproductreleaseforseveralradioisotopes duringovertemperature condition isdepictedgraphically inFigures2-11and2-12.Toconstruct thefigures,theextentoffueldamage,expressed asapercentage ofthecore,isplottedasalinearfunctionofthepercentage ofthesourceinventory releasedforvariousnuclides.

Thevaluesusedinconstructing thegraphswereobtainedfromTable2-10.Forexample,if100percentofthecoreexperienced overtemperatures, 52percentofXe-133coreinventory wouldbereleased.

If1percentofthecoreexperienced overtemperature, 0:52percentofXe-133coreinventory wouldbereleased.

Theassumption isalsomadethatnuclidesofanyelement,e.g.,I-131andI-133,havethesamemagnitude ofrelease.Inordertoapplythesefigurestoaparticular plant,power,decay,anddilutioncorrections described earlierinthisreportmustbeappliedtotheconcentrations ofnuclidesdetermined fromanalysisofradionuclide samples.Themaximumandminimumestimates of.releasepercentages arethosegiveninTable2-10astherangeofvalues:nominalvaluesofreleasearesimpleaveragesofthemiminumandmaximumvalues.2.6RELATIONSHIP OFNUCLIDERELEASEWITHCOREMELTCONDITIONS Fuelpelletmeltingleadstorapidreleaseofmanynoblegases,halides,andcesiumsremaining inthefuelafteroverheatconditions.

Significant releaseofthestrontium, barium-lanthanum chemicalgroupsisperhapsthemostdistinguishing featureofmeltreleaseconditions.

Valuesofthereleaseoffissionproductsduringfuelmeltconditions arederivedfromex-pileexperiments performed byvariousinvestigators.

70.50'0'0'o~5C$Cl3~r~Qr2~OCJ)SO0~70~0~0~0IAh..OOOF7OOOV)KOFuelOvertemperature (5)FIGURE2-1lRELATIONSHIP OFXFUELOYERTEMPERATURE WITHXCOREINYENTORY RELEASEDOFXE,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-l2RELATIONSHIP OF'AFUELOVERTEMPERATURE WITHXCOREINVENTORY RELEASEDOFBAORSR Thesereleasemeasurements havebeenexpressed asreleaseratecoefficients forvarioustemperature regimes.Thesereleaseratecoefficients havebeenrepresented byasimpleexponential equationindraftNUREG-0956.

Thisequationhastheform:K(T)K(T)Aewherereleaseratecoefficient A&8=constants temperature.

Thesereleaseratecoefficients wereutilizedwithcoretemperature profilestodevelopfissionproductreleaseestimates forvariousaccidentsequences forwhichcoremeltispostulated indraftNUREG-0956.

Fissionproductreleasepercentages forthreeaccidentsequences whichleadto100percentcoremeltaregiveninTable2-11.Thexenon,krypton,cesium,iodine,andtellurium

'elements havebeenarrangedintoasinglegroupbecauseofsimilarity intheexpectedmagnitude ofovertemperature release.Theassumption isalsomadethatnuclidesofanyelemente.g.,Iodine131andIodine133,havethesamemagnitude ofrelease.Thedifferences inthecalculated releasesofthevariouselementsforthedifferent accidentsequences wereusedtodetermine minimumandmaximumvaluesofexpectedrelease;nominalvaluesofreleasearesimpleaveragesofallreleasevalueswithinagroup.Thepercentage releaseofvariousnuclideshasbeencorrelated topercentage ofcoremeltwiththelinearextrapolations showninFigures2-13through2-15.2.7SAMPLINGLOCATIONS AsurveyofanumberofMestinghouse plantshasindicated thatthepostaccidentsamplingsystemlocations forliquidandgaseoussamplesvariesforeachplant.Toobtainthemostaccurateassessment ofcoredamage,itisrecommended tosampleandanalyzeradionuclides fromthereactorcoolantsystem,thecontainment atmosphere, andthecontainment sump(ifavailable).

Othersamplescanbetakendependent ontheplant'scapabilities.

The TABLE2-11PERCENTACTIVITYRELEASEFOR100PERCENTCOREMELTCONOITIONS Large*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*Calculated releasesforsevereaccidentscenarios withoutemergency safeguard

features, takenfromdraftNUREG-0956

• • NominalreleaseareaveragesofXe,Kr,I,Cs,andTegroups,orSrandBagroups.***Maximumandminimumreleasesrepresent extremesofthegroups.

100.70.SO~30~20'OroryPp0~70~0~0~0'IAhOOhlOOOOVlhOFuelMelt(%%d)FIGURE213RELATIONSHIP OF%%dFUELMELTWITH%%doCOREINVENTORY RELEASEOOFXE,KR,I,CS,ORTE 100.010.00.10.011.010.0FuelMelt(A)100.0FIGURE2-14RELATIONSHIP OF%FUELMELTWITH/oCOREINVENTORY RELEASEDOFBAORSR 100.010.01.00.10.010.0011.010.0FuelMelt(1)100.0FIGURE2-15RELATIONSHIP OF%%uFUELMELTWITHXCOREINVENTORY RELEASEDOFPR50 specificsamplelocations tobeusedduringtheinitialphasesofanaccidentshouldbeselectedbasedonthetypeofaccidentinprogress.

Ifthetypeofaccidentscenarioisunknown,knownplantparameters (pressure, temperature, levelindications, etc.)canbeusedasabasistodetermine theprimesamplelocations.

Consideration shouldbegiventosamplingsecondary systemifasignificant leakfromtheprimarysystemtosecondary systemisnoted.Table2-12presentsalistofthesuggested samplelocations fordifferent accidentscenarios basedontheusefulness oftheinformation derivable fromthesample.t0.C.Cook'sPASSisequippedtoobtainsamplesfromhotloop1and3,eastandwestRHR,containment sump,pressurizer steamspaceandcontainment air.Plantpersonnel wi11useTable2-12asaguideindetermining samplelocations, butfinaldiscretion isleftuptotheplantpersonnel.

51

,SuestedSamlinLocations ScenarioPrincipal SamlinLocations OtherSamlinLocations SmallBreakLOCAReactorPower>lg"ReactorPower<lg"RCSHotLeg,Containment Atmosphere RCSHotLegRCSPressurizer RCSPressurizer LargeBreakLOCAReactorPower>15*ReactorPower<15"SteamLineBreakContainment Sump,Containment Atmosphere, RCSHotLeg'ontainment Sump,Containment Atmosphere RCSHotLeg,RCSPressurizerContainment Atmosphere SteamGenerator TubeRuptureIndication ofSignifi-cantContainment SumpInventory RCSHotLeg,Secondary SystemContainment Sump,Containment Atmosphere Containment Atmosphere Containment BuildingRadiation MonitorAlarmSafetyInjection ActuatedContainment Atmosphere, Containment SumpRCSHotLegRCSPressurizer Indication ofHighRadiation LevelinRCSRCSHotLegRCSPressurizer Assumeoperating atthatlevelforsomeappreciable time.

3.0 AUXILIARY

INOICATORS Thereareplantindicators monitored duringanaccidentwhichbythemselves cannotprovideausefulestimatebutcanprovideverification oftheinitialestimateofcoredamagebasedontheradionuclide analysis.

Theseplantindicators includecontainment hydrogenconcentration, coreexitthermocouple temperatures, reactorvesselwaterlevel,andcontainment radiation level.Whenproviding anestimateforcoredamage,theseplantindicators, ifavailable, shouldconfirmtheresultsoftheradionuclide analysis.

Forexample,ifthe,coreexitthermocouple readingsandreactorvesselwaterlevelindicateapossibility ofcladdamageandtheradionuclide concentrations indicatenocladdamage,thenarecheckofbothindications maybeperformed orcertainindications maybediscounted basedonengineering judgment.

3.1CONTAINMENT HYOROGENCONCENTRATION Anaccident, inwhich'thecoreisuncovered andthefuelrodsareexposedtosteam,mayresultinthereactionofthezirconium ofthecladdingwiththesteamwhichproduceshydrogen.

Thehydrogenproduction characteristic ofthezirconium waterreactionisthatForeverymoleofzirconium thatreactswithwater,twomolesofhydrogenareproduced.

Forthismethodology itisassumedthatallofthehydrogenthatisproducedisreleasedtothecontainment atmosphere.

Thehydrogendissolved intheprimarysystemduringnormaloperation isconsidered tocontribute aninsignificant amountofthetotalhydrogenreleasedtothecontainment.

ForUnit1andUnit2,thereleaseofthedissolved hydrogenandthehydrogeninthepressurizer gasspacetothecontainment corresponds toacontainment hydrogenconcentration ofO.lpercentbyvolume,whichcanbeconsidered insignificant withintheaccuracyofthisreport.Intheabsenceofhydrogencontrolmeasures, monitoring thiscontainment hydrogenconcentration duringtheaccidentcanprovideanindication oftheextentofzirconium waterreaction.

Thepercentage ofzirconium waterreactiondoesnotequalthepercentage ofcladdamagedbutitdoesprovideaqualitative verificati'on oftheextentofcladdamageestimated fromtheradionuclide analysis.

53 Figure3-1showstherelationship betweenthehydrogenconcentration andtheperce'ntage ofzirconium waterreactionforUnit1andUnit2.Therelationship showninFig'ure3-1doesnotaccountforanyhydrogendepletion duetohydrogenrecombiners andhydrogenignitions.

Therecombiners thatnowexistarecapableofdealingeffectively withtherelatively smallamountsofhydrogenthatresultfromradiolysis andcorrosion following adesignbasisLOCA.However,theyareincapable ofhandlingthehydrogenproducedinanextensive zirconium-steam reactionsuchaswouldresultfromseverecoredegradation.

Currentrecombiners canprocessgasthatisapproximately 4to5percenthydrogenorless.Eachrecombiner unitcanprocessaninput(10)flowintherangeof100SCFMto200SCFM.Nithintheaccuracyofthismethodology, itisassumedthatrecombiners willhaveaninsignificant effectI'nthehydrogenconcentration whenitisindicated thatextensive zirconium-steam reactioncouldhaveoccurred.

Uncontrolled ignitionofhydrogenanddeliberate-ignitionwillhinderanyquantitative useofhydrogenconcentration asanauxiliary indicator.

However,theoxygenamountdepletedduringtheburn,ifknown,canbeusedtoestimatetheamountofhydrogenburned.Iftheoxygenamountdepletedisnotknown,itcanbeassumedthatforignitionofhydrogentooccuraminimalconcentration of4percenthydrogenisneeded.SinceUnits1and2areicecondenser containments, deliberate ignitionofthehydrogenisutilizedtocontrolthecontainment hydrogenconcentration.

Asstatedabove,aminimalconcentration of4percenthydrogenisneeded.Thisassumption canbeusedqualitatively toindicatethatsomepercentage ofzirconium hasreacted,butitisdifficult todetermine theextentofthereaction.

Containment hydrogenconcentrations canbeobtainedfromthePostAccidentSamplingSystemorthecontainment gasanalyzers.

Figure3-1showstherelationship betweenthehydrogenconcentration (percentvolume)andthepercentage ofzirconium waterreactionforUnit1andUnit2.Thehydrogenconcentration shownistheresultoftheanalysisofadrycontainment sample.Thecurveswerebasedonaveragecontainment volumesandtheaverageinitialzirconium massofthefuelrodsforeachunit,whichareshowninTable3-1.Table3-1alsopresentsthecorrelation betweenhydrogenconcentration andpercentage ofzirconium waterreaction.'o usetheauxiliary indicator ofhydrogenconcentration, theassumptions werethatallhydrogenfromzirconium waterreactionisreleasedtocontainment, awell-mixed atmosphere, andidealgasbehaviorincontainment.

30..25'0.C)Ii5~IoCJ<0~UNITUNIT1/"/OClZIRC-WATER REACTIONPERCENTAGEFIGURE3-1CONTAINMENT HYDROGENCONCENTRATION BASEDONZIRCONIUM WATERREACTION55 TABLE3-1CONTAINMENT VOLUHEANOZIRCONIUH HASSPlantTeZirconium HassibmContainment VolumeSCFUnit1Unit244,54750,9131.2x1061.2x10'6Relationship betweenhydrogenconcentration ofadrysampleandfractionofzirconium waterreactionisbasedonthefollowing formula.~oo2(FZWR)(ZM)(H)

+Vwhere:FZWR=fractionofzirconium waterreactionZM=totalzirconium mass,ibmH=conversion factor,7.92SCFofHperpoundofzirconium reactedV=containment volume,SCF 3e2COREEXITTEMPERATURES ANDREACTORVESSELWATERLEVELSCoreexitthermocouples

'(CETCs)measurethetemperature ofthefluidatthecoreexitatvarSousradSalcorelocations

~<(FSgure 3-2)J.Thetypicalthermocoupl esystemisqualified toreadtemperatures ashighas1650'F.Thisistheabilityofthesystemtomeasurethefluidtemperatures attheincorethermocouples locations andnotcoretemperatures.

Mostreactorvessellevelindication systems(RVLIS)usedifferential pressure(d/p)measuring devicestomeasurevessellevelorrelativevoidcontentofthecirculating primarycoolantsystemfluid.Thesystemisredundant andincludesautomatic compensation forpotential temperature variations oftheimpulselines.Essential information isdisplayed inthemaincontrolroominaformdirectlyusablebytheoperator.

RVLISandCETCreadingscanbeusedforverification ofcoredamageestimates inthefollowing ways(11)'uetotheheattransfermechanisms betweenthefuelrods,steam,andthermocouples, thehighestcladtemperature willbehigherthantheCETCreadings.

Therefore, ifthermocouples readgreaterthan1300'F,cladfailuremayhaveoccurred.

1300'Fisthelowerlimitforcladdingfailures.

oIfanyRCPsarerunning,theCETCswillbegoodindicators ofcladtemperatures andnocoredamageshouldoccursincetheforcedflowofthesteam-water mixturewilladequately coolthecore.IfRCPsarenotrunning,thefollowing apply.oNogeneralized coredamagecanoccurifthecorehasnotuncovered.

SoifRVLISfullrangeindicates thatthecollapsed liquidlevelhasneverbeenbelowthetopofthecoreandnoCETChasindicated temperatures corresponding tosuperheated steamatthecorresponding RCSpressure, thennogeneralized coredamagehasoccurred.

57 QTQT00TT6-QOO0T0T90o8TJOTti0Tl3IQl5TOT0TOTTTTOT0TTQTOTO-2700'=FLUXTtttttSLE T=THERHOCOUPL.E Distribution ofThermocouples andFluxThimblesforUnit1andUnit2'Figure3-258ttF~hX

oIfRVLISindicates lessthan3.5ft.collapsed liquidlevelinthecoreorCETCsindicatesuperheated steamtemperatures, thenthecorehasuncovered andcoredamagemayhaveoccurreddepending onthetimeafterreactortrip,lengthanddepthofuncovery.

Bestestimatesmallbreak(1to4inches)analysesandtheThreeMileIsland(TMI)accidentdata(12)indicatethatabout20minutesafterthecoreuncoverscladtemperatures starttoreach1200'Fand10minuteslatertheycanbeashighas2200'F.Thesetimeswillshortenasthebreaksizeincreases duetothecoreuncovering fasterandtoagreaterdepth.oIftheRVLISindication isbetween3.5ftcollapsed liquidlevelinthecoreandthetopofthecore,thentheCETCsshouldbemonitored forsuperheated steamtemperatures todetermine ifthecorehasuncovered.

Asmanythermocouples aspossibleshouldbeusedforevaluation ofthecore(11)temperature conditions.

TheEmergency ResponseGuidelines recommend thataminimumofone'thermocouple nearthecenterofthecoreandoneineachquadrantbemonitored atidentified highpowerassemblies.

Cautionshouldbetakenifathermocouple readsgreaterthan1650'Forisreadingconsiderably different thanneighboring CETCs.Thismayindicatethatthethermocouple hasfailed.CautionshouldalsobeusedwhenlookingatCETCsnearthevesselwallsbecauserefluxcoolingfromthehotlegsmaycoolthefluidinthisarea.CETCscanalsobeusedasanindicator ofhotareasinthecoreandmaybeusedtodetermine radiallocationofpossiblelocalcoredamage.Therefore, coreexitthermocouples andRVLISaregenerally regardedasreliableindicators ofRCSconditions thatmaycausecoredamage.Theycanpredictthetimeofcoreuncoverytowithinafewminutesbymonitoring thecoreexitthermocouples forsuperheat afterRVLISindicates collapsed liquidlevelatthetopofthecore.Theonsetandextentoffueldamageaftercoreuncoverydependontheheatgeneration inthefuelandtherapidityanddurationofuncovery.

However,ifthecorehasnotuncovered, nogeneralized fueldamagehasoccurred.

Coreexitthermocouples reading1300'Forlargerindicatethelikelihood ofcladdamage.59

3.3CONTAINHENT RADIATION HONITORSANOCOREDAMAGEIpostaccidentradiation monitorsinnuclearplantscanbeusedtoestimatethexenonandkryptonconcentrations inthecontainment.

Ananalysishasbeenmadetocorrelate thesemonitorreadingsinR/hrtoestimategaseousradioactivity concentrations.

Forthisanalysisthefollowing assumptions weremade:1.Radiogases releasedfromthefuelareallreleasedtocontainment.

2.Accidents wereconsidered inwhich100Kofthenoblegases,52Kofnoblegases,and0.3$ofthenoblegaseswerereleasedtothecontainment.

3.Halogensandotherfissionproductsareconsidered nottobesignificant contributors tothecontainment monitorreadings.

Arelationcanbedeveloped whichdescribes thegammarayexposurerateofadetectorwithtime,basedontheamountofnoblegasesreleased.

Theexposureratereadingofadetectorisdependent onplantspecificparameters:

theoperating powerofthecore,theefficiency ofthemonitor,andthevolumeseenbythemonitor.Theplantspecificresponseofthedetectorasafunctionoftimefollowing theaccidentcanbecalculated fromtheinstantaneous gammaraysourcestrengths duetonoblegasrelease,Table3-2,andtheplantcharacteristics oFthedetector.

Thegamma.ray sourcestrengths presented inTable3-2arebasedon100percentreleaseofthenoblegases.Todetermine theexposurerateofthedetectorbasedon52percentand0.3percentnoblegasrelease,52percentand0.3percent,respectively, ofthegambiaraysourcestrengthareused.Alternately, theenergyratesinMev/watt-sec giveninTable3-2canbeexpressed intermsofaninstaneous fluxbyassumingtheenergyisabsorbedinacmoFair.Theseenergyratevalues,inMev/watt-sec-cm

,whendivided33bydiscretevaluesofMev/photon andthegambiaabsorption coefficient forair,]-5-1p,considered asaconstant(3.5x10cm),providevaluesofthephotonflux,photons/watt-cm

-sec,asshowninTable3-2A.Thediscrete2valuesofHev/photon wereobtainedby'usingtheaveragevaluesoftheenergygroups,Hev/game, fromTable3-2.60

TABLE3-2INSTANTANEOUS GAMMARAYSOURCESTRENGTHS OUETOA100PERCENTRELEASEOFNOBLEGASESATVARIOUSTIMESFOLLOWING ANACCIOENTEnerGrouSourceStrenthatTimeAfterReleaseMe'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'ARELEASEOFNOBLEGASESATVARIOUSTIMESFOLLOWING ANACCIDENTEnerGrou/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$releasesareindicative ofcladfailures, valuesbetween0.3$and525releaseareintheFuelpelletovertemperature regions,whilevaluesbetween525-releaseand100$releaseareinthecoremeltregime.Torepresent thereleaseofthenormaloperating noblegasactivityintheprimarycoolantasobtainedfromANS18.1,1.0x105ofthe(6)-3gammaraysourcestrengthisused.Inactualpracticeitmustberecognized thatthereisoverlapbetweentheregimesbecauseofthenatureinwhichcoreheatingoccurs.ThehottestportionoFthecoreisinthecenterduetofluxdistribution andhencegreaterfissionproductinventory.

Additionally heattransferisgreateratthecoreperiphery duetoproximity ofpressurevesselwalls.Thusconditions couldexistwherethereissomemoltenfuelinthecenterofthecoreandovertemperature conditions elsewhere.

Similarconditions canoccurwhichleadtoovertemperature inthecentralportionsofthecore,andcladdamageelsewhere.

Thus,estimation ofextentofcoredamagewithcontainment radiation readingsmustbeusedinaconfirmatory sense-asbackuptoothermeasurements offissionproductreleaseandotherindicators suchaspressurevesselwaterlevelsandcoreexitthermocouples.

Figure3-3presentstherelationship ofthereading(R/hr)ofUnit1andUnit2highrangecontainment arearadiation monitorsasafunctionoftimefollowing reactorshutdown.

Eachunithastwohighrangemonitorswithonemonitormountedapproximately 7feetabovetheoperating floorbetweenloop2andloop3steamgenerator doghouses andtheothermonitormountedinthelowercompartment ontheoutsidecontainment wall.63 1.0+71005NOBLEGASRELEASE1.0+552ÃNOBLEGASRELEAS1.0+30.35NOBLEGASRELEASEANS18.1NORMALOPERATING NOBLEGASRELEASE1.01.0-2"1.010.0100.0TIMEAFTERSHUTDOWN(HOURS)fIGURE3-3PERCENTNOBLEGASESINCONTAINMENT FORUNIT1ANDUNIT264

4.0 GENERALIZED

COREOAMAGEASSESSMENT APPROACHIISelectedresultsofvariousanalysesoffissionproductrelease,coreexitthermocouple

readings, pressurevesselwaterlevel,containment radiogasmonitorreadingsandhydrogenmonitorreadingshavebeensummarized inTable4-1.Theintentofthesummaryistoprovideaquicklookatvariouscriteriaintendedtodefinecoredamageoverthebroadrangesof:NoCoreDamage0-50K50-100%0-50$50-100%0-50550-100'Xcladfailurecladfailurefuelpelletovertemperature fuelpelletovertemperature fuelmeltfuelmeltIAlthoughthistableisintendedforgenericapplicability tomostMestinghouse pressurized waterreactors, exceptwherenoted,variouspriorcalculations arerequiredtoascertain percentage releasefractions, power,andcontainment volumecorrections.

Thesecorrections aregivenwithinthepriortextofthistechnical basisreport.Theusershoulduseasmanyindicators aspossibletodifferentiate betweenthevariouscoredamagestates.Becauseofoverlapping valuesofreleaseandpotential simultaneous conditions ofcladdamage,overtemperature, and/orcoremelt,considerable judgement needstobeapplied.II65 TABLE4-1CHARACTERISTICS OFCATEGORIES OFFUELOAHAGE*CoreDamageIndicator CoreDamageCategoryPercentandTypeofFissionProductsReleasedFissionProductRatioContainment RadiogasHonitor(R/hr)10hrsaftershutdown**

CoreExitThermocouples Readings(oegF)CoreUncoveryIndication NydrogenHonitor(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-0.21-1310.3-0.51-1330.1-0.2NotApplicable Kr-$70.0221-1330.71Kr-87~0.022I"133~0.710-660660to1325<750750-13001300-1650NouncoveryCoreuncoveryCoreunqoveryNeg1Igible0-\313-240-50$fuelpelletovertemperature 50-TOOLfuelpelletovertemperature 0-50Kfuelmelt50-100KfuelmeltXe-Kr.Cs,I 1"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"Thistableisintendedtosupplement themethodology outlinedinthisreportandshouldnotbeusedMithoutreferring tothisreportandwithoutconsiderable engineering

)udgement.

""Valuesshouldberevisedpertimesotherthan10hours.***Ignitorsmayobviatethesevalues.Ail*-Lrr-87~-133Xe-133'-131

5.0 LIHITATIONSTheemphasisofthismethodology

isonradiochemical analysisofappropriate liquidandgaseoussamples.Theassumption hasbeenmadethatappropriate post-accident systemsareinplaceandfunctional andthatrepresentative samplesareobtained.

Ofparticular concern,intheareaofrepresentative

sampling, isthepotential forplateoutinthesamplelines.Inordertoprecludesuchplateout, itisassumedthatproperattention toheattracingofthesamplelinesandmaintenance ofsufficient purgevelocities isinherentinthesamplingsystemdesign.Havingobtainedarepresentive sample,radiochemical analysisviagammaspectrometry areusedtocalculate thespecificactivityofvariousfissionproductsreleased.

Radiochemical analysesoffissionproductsundernormalplantoperating conditions areaccurateto+10percent.Radiochemical analysesofpostaccidentsampleswhichmaybemuchmoreconcentrated, andcontainunfamiliar

nuclides, andwhichmustbeperformed expeditiously mayhaveanerrorbandof20to50percent.Havingobtainedspecificactivity-analysis, thecalculation oftotalreleaserequiresknowledge ofthetotalwatervolumefromwhichthesamplesweretaken.Caremustthusbeexercised inaccounting forvolumesofanywateradded.viaECCSandspraysystems,accumulators, chemicaladditiontanks,andmeltingiceoficecondenser plants.Additionally estimates oftotalsumpwatervolumeshavetobedetermined withdatafromsumplevelindicators.

Suchestimates ofwatervolumeareprobablyaccurateto+10percent.Thespecificactivityalsorequiresacorrection toadjustforthedecayofthenuclideinwhichthemeasuredspecificactivityisdecaycorrected totime.ofreactorshutdown.

Forsomenuclides, precursor effectsmustbeconsidered inthedecaycorrection calculations.

Theprecursor effectislimitedtoparent-daughter relationships forthismethodology.

Amajorassumption ismadethatthereleasepercentages oftheparentanddaughterareequal.Forovertemperature andmeltreleases, thisassumption isconsistent withthetechnical basispresented inSections2.5and2.6,butthegapreleasescouldbedifferent byasmuchasafactorof2.67 Themodelsusedforestimation offissionproductreleasefromthegapactivityarebasedontheANS5.4standard.

Background

materialforthis,reportindicatethemode(,thoughempirical, isbelievedtohaveanaccuracyof20-25percent.Inourapplication ofthesemodelstocorewideconditions, thecorehasarbitrarily beendividedintothreeregionsoflow,intermediate, andhighburnup.Thisrepresentation predicted nominalvaluesofreleasewithmaximumandminimumvaluesthatapproach+100percentofthenominalvalue.Therefore theseestimates ofcoredamageshouldonlybeconsidered accuratetoafactorof2.Themodelsemployedforestimates ofreleaseathighertemperature havenotbeencompletely verifiedbyexperiment.

Additionally, calculations ofexpectedcoretemperatures forsevereaccidentconditions arestillbeing'efined.

Theseuncertainties areexacerbated bythemannerinwhichvariousaccidentscenarios leadingtocoremelthavebeencombinedtoproducefissionproductreleasepredictions forthecoremeltcondition.

Consideration ofthemeltreleaseestimates showninTable2-11fortherefractory nuclidesindicatearangeofapproximately

+70percent.Fromtheseconsiderations itisclearthatthecombineduncertainties aresuchthatcoredamageestimates usingthismethodology aresufficient onlytoestablish majorcategories offueldamage.Thiscategorization, andconfirmation ofsubcategorization willrequireextensive additional analysisforsomeseveraldayspasttheaccidentdate.68

7.0REFERENCES

1."Clarification ofTHIActionPlanRequirements,"

NUREG-0737, USNRC,November1980.2."AReporttotheCommission andtoPublic,NRCSpecialInquiryGroup,"H.Rogovin,1980.3."ORIGENIsotopeGeneration andDepletion Code,"OakRidgeNationalLaboratory, CCC-217.4.Methodofcalculating thefractional releaseoffissionproductsfromoxidefuel,ANSI/ANS5.4-1982.5."IodineandCesiumSpikingSourceTermsforAccidentAnalyses,"

WCAP-9964, Westinghouse ElectricCorporation, July1981.6."SourceTermSpecification,"

ANS18.1Standard1976.7."Radionuclide ReleaseUnderSpecificLWRAccidentConditions,"

DraftNUREG-0956, USNRC,January1983.8."ReleaseofFissionProductsFromFuelinPostulated DegradedAccidents,"

IOCORDRAFTReport,July1982.9."THI-2Accident:

CoreHeat-upAnalysis,"

NSAC/24,January1981.10."LightWaterReactorHydrogenManual,"NUREG/CR-2726, August1983.11."Westinghouse OwnersGroupTransmittal ofVolumeIIIforHighPressureofEmergency ResponseGuidelines,"

0.0.Kingsley, Jr.to0.G.Eisenhut, LetterNo.OG83,SectionFR-C.l,January1983.69 12.AnalysisoftheThreeMileIslandAccidentandAlternative Sequences, PreparedforNRCbyBattelle, ColumbusLaboratories, NUREG/CR-1219, January1980.13.Westinghouse Owner'sGroupPostAccidentCoreDamageAssessment Methodo1ogy, Revision1,March,1984.70 INDIANAhMICHIGANELECTRICCOMPANYDONALDC.COOKNUCLEAR.PLANTUNIT1ANDUNIT2POSTACCIDENTCOREDAMAGEASSESSMENT

1.0 OBJECTIVE

1.1Thepurposeofthisprocedure isto'rovide amethodtoclassifyandestimatetheextentofcoredamagethroughmeasurement offissionproductsreleasedtothecoolantandcontainment atmosphere togetherwithauxiliary measurements ofcoreexitthermocouple temperature, waterlevelwithinthepressurevessel,containment radiation

monitors, andcontainment atmosphere hydrogenmonitors.

2.0REFERENCES

2.1Mestinghouse OwnerGroupPostAccidentCoreDamageAssessment Methodology, Revision1,March1984.3.0RESPONSIBILITIES 3.1ThePlantEvaluation TeamintheTechnical SupportCenterwillberesponsible forcoredamageassessment basedonradionuclide analysisandauxiliary measurements.

4.0 APPLICABILITY

4.1Anyplant.condition inwhichtheoperatorwouldsuspectalossofreactorcorecoolingorreactorcorecoolingcannolongerbemaintained.

4.2Anyplantcondition inwhichtheoperatorwouldsuspectfailedfuel,andanestimateoftheamountoffailedfuelisrequired.

5.0 INSTRUCTIONS

5.1NuclideSampling5'.1Requestsamplesofreactorcoolant,containment atmosphere, andcontainment sumpasindicated inTable2.Table11'iststheselectednuclidesforcoredamageassessment.

5.1.2Analyzetheselectedsamplesforisotopicspecificactivitywithnodecaycorrection appliedtosampleactivities.

5.1.3CompleteTable3A,RCSActivityWorksheet, ifsamplewasavailable asfollows:5.1.3.1Recordelapsedtimefromreactorshutdowntosamplecount.5.1.3.2Recordspecificactivities ofnuclidesinCi/gm.5.1.3.3Determine andrecorddecaycorrection factorusingTable.4,DecayCorrection FactorWithParent-Daughter Effect.95.1.3.4Determine andrecordthecorrected specificactivitybymultiplying themeasuredspecificactivitybythedecaycorrection factor.5.1.4CompleteTable3B,Containment SumpActivityWorksheet, ifsamplewasavailable, asfollows:5.1.4.1Recordelapsetimefromreactorshutdowntosample.count.

5.1.4.2Recordspecificactivities ofnuclides.

5.1.4.3Oetermine andrecorddecaycorrection factorusingTable4,OecayCorrection FactorWithParent-Oaughter Effect.5.1.4.4Oetermine andrecordthecorrected specificactivitybymultiplying themeasuredspecificactivitybythedecaycorrection factor.5.1.5CompleteTable3C,Containment Atmosphere ActivityWorksheet asfol1ows:5.1.5.1Recordelapsetimefromreactorshutdowntosamplecount.5.1.5.2Recordspecificactivities ofnuclides.

5.1.5.3Oetermine andrecorddecaycorrection factorusingTable4,OecayCorrection FactorWithParent-Oaughter Effect.5.1.5.4Oetermine andrecordthecorrected specificactivitybymultiplying themeasuredspecificactivitybythedecaycorrection factor.5.2LiquidMass5.2.1Estimatethetotalliquidmassbycompleting Table5,EstimateofTotalLiquidMassWorksheet.

5.2.2IfbothaRCSsampleandacontainment sumpsamplewasobtained, anestimateoftheRCSwatermassandcontainment watermassisneeded.UseTable6,EstimateofRCSWaterMass andContainment WaterMassWorksheet toestimatethedistribution ofthewater.RecordtheRCSmassinTable3Aandthecontainment massinTable3B.5.2.3Ifonlyoneoftheliquidsamples(RCSorcontainment sump)wasobtained, usethetotalliquidmasscalculated in5.2.1asthewatermassassociated withthatsample.RecordwaterineitherTable3A(RCS)orTable3B(containment sump).t5.3Containment Volume5.3.1Sincethecontainment atmosphere sampleiscollected atthecontainment buildingpressureandthesamplevolumeisnotcorrected tostandardconditions, noadjustment factorisneededtotheknowncontainment volume.Theknowncontainment volume(3.5xl0cc)isrecordedinTable3C.105.4TotalActivityReleased5.4.1RCS5.4.1.1Calculate totalactivityofeachnuclidereleasedtotheRCSbymultiplying thedecaycorrected specificactivitybytheRCSmass.RecordinTable3A.5.4.2Containment Sump5.4.2.1Calculate totalactivityofeachnuclidereleasedtothecontainment waterbymultiplying thedecaycorrected specificactivitybythecontainment watermass.RecordinTable3B.

5.4.3Containment Atmosphere 5.4.3.1Calculate totalactivityofeachnuclidereleasedtothecontainment atmosphere bymultiplying thedecaycorrected specificactivitybythecontainment volume.RecordinTable3C.5.4.4TotalActivityReleasedofEachNuclide5.4.4.1RecordinTable7,TotalReleaseActivity/Percent

Released, theactivityofeachnuclideofeachsamplelocation.

5.4.4.2Sumtheactivities ofeachnuclideofeachsampletodetermine totalactivityreleasedofeachnuclide,RecordinTable7.5.5TotalCoreInventory 5.5.1PowerHistory5.S.1.1RecordinTable8,PowerCorrection Factor,theplantpowerhistoryduringthe30dayspriortoshutdown.

5.5.2PowerCorrection Factor5.5.2.1Ifpowerhistoryindicates steadystatepowerlevelduringthe30daysor4days(depending onthenuclide)priortoshutdown, usethesteadystatepowercorrection equationshowninTable8todetermine powercorrection factor(PCF).RecordinTable7.5.S.2.2Ifpowerhistoryindicates fluctuating powerlevelsduringthe30dayspriortoshutdown, usethetransient powercorrection equationshowninTable8todetermine powercorrection factor(PCF).RecordinTable7.

5.5.2.3Todetermine thepowercorrection factorforCs-134firstdetermine theaveragepowerduringtheentireoperating periodduringthecyclepriortoshutdown.

UsethisaveragepowerandFigure4toestimatepowercorrection factor.RecordinTable7.5.5.3AdjustedCoreInventory 5.5.3.1Determine andrecordinTable7theadjustedcoreinventory foreachnuclidebymultiplying theequilibrium full-power inventory (listedinTable7)bythepowercorrection factor.5.6Estimation ofPercentFuelDamage5.6.1Determine thepercentage ofthecorrected coreinventory releasedofeachnuclidebydividingthetotalactivityreleasedbythecorrected coreinventory.

RecordinTable7.5.6.2Usingtheappropriate coredamagegraphs,Figures5through17,determine thepercentcladfailure,fuelovertemperature, andfuelmeltasafunctionofthenuclidereleasepercentage.

Usethecurvethatbestrepresents coreburnup.Recordthepercentages ofcladdamage,fuelovertemperature, andfuelmeltinTable10,CoreDamageAssessment Evaluation Sheet.Note:Iodinespikingshouldbeconsidered forcaseswheretheassessment isbetweennofueldamageandminorcladfailure.Ifpercentcladfailureisnotinagreement withvaluesobtainedfromothernuclides, spikingmayhaveoccurred.

RefertoFigure8ifthisisthecase..5.7NuclideActivityRatios5.7.1Determine theactivityratiosfornoblegasesandiodinesbycompleting Tablell,NuclideActivityRatios.

5.7.2Comparethecalculated activityratioswiththegapactivityratiosandfuelpelletratioslistedinTablell.Calculated activityratioslessthangapactivityratiosareindicative ofcladfailures.

Calculated activityratiosgreaterthangapactivityratiosareindicative ofmoreseverefailures(fueloverheatandfuelmelt).5.7.3RecordinTable10thecalculated coredamagestate.5.8Auxiliary Indicators 5.8.1Oetermine fromreactorvessellevelinstrumentation orothersourcesifatanytimethecorebecameuncovered.

Nouncoveryisindicative ofnofueldamage,andcoreuncoveryisindicative ofallcoredamagestates.RecorduncoveryhistoryinTable10.5.8.2Obtaincoreexitthermocouple readingsandcomparethesevalueswiththoselistedinTable12.8asedonTable12,Characteristics ofCategories ofFuelOamage,recordtemperature inTable10underappropriate coredamagestate.5.8.3Obtaincontainment hydrogenconcentration.

Comparehydrogenconcentration hydrogenconcentration underappropriate coredamagestate.5.8.4Usehydrogenconcentration withFigure18todetermine extentofzirconium-water reaction.

Recordpercentage ofzirconium waterreactioninTable10.Note:Ifignitorshavebeenactivated oraburnhasbeenindicated, quantitative useofthehydrogenconcentration islimited.Itcanbeassumedthatforignitionofhydrogentooccuraminimalconcentration of4percenthydrogenisneeded.Thisassumption can beusedqualitatively toindicatethatsomepercentage ofzirconium hasreacted,butitisdifficult todetermine extentofthereaction.

5.8.5Obtainthecontainment highrangearearadiation monitorreadingsandthetimeaftershutdownthereadingswereobtained.

ComparethereadingswithFigure19toestimatethecorresponding extentofcoredamage.RecordthemonitorreadinginTable10undertheappropriate coredamagestate.5.9CoreDamageAssessment 5.9.1Performthefinalcoredamageassessment byevaluating thedatainTable10.Itisunlikelythatcompleteagreement betweentheindicators willresultinthesameestimateofcoredamage.Theevaluation shouldbethebestestimatebasedonallparameters, theirinterrelationship, andengineering judgment.

Theusershoulduseasmanyindicators aspossibletodifferentiate betweenthevariouscoredamagestates.Becauseofoverlapping valuesofreleaseandpotential simultaneous conditions ofcladdamage,overtemperature, and/orcoremelt,considerable judgement needstobeapplied.

TABLE1SELECTEONUCLIOESFORCOREDAMAGEASSESSMENT CoreDamageStateNuclideHalf-Life*

Predominant GamasKevYieldX*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.**Thesenuclidesaremarginalwithrespecttoselection criteriaforcandidate nuclides; theyhavebeenincludedonthepossibility thattheymaybedetectedandthusutilizedinamanneranalogous tothecandidate

nuclides, TABLE2SuestedSamlinLocations ScenarioPrincipal SamlinLocations OtherSamlinLocations SmallBreakLOCAReactorPower>lg*ReactorPower<lg*LargeBreakLOCAReactorPower>lg*ReactorPower<lX*RCSHotLeg,Containment Atmosphere RCSHotLegContainment Sump,Containment Atmosphere, RCSHotLegContainment Sump,Containment Atmosphere RCSPressurizer RCSPressurizer SteamLineBreakSteamGenerator TubeRuptureIndication ofSignifi-cantContainment SumpInventory RCSHotLeg,RCSHotLeg,Secondary SystemContainment Sump,Containment Atmosphere RCSPressurizer Containment Atmosphere Containment Atmosphere Containment BuildingRadiation MonitorAlarmSafetyInjection ActuatedContainment Atmosphere, Containment SumpRCSHotLegRCSPressurizer Indication ofHighRadiation LevelinRCSRCSHotLegRCSPressurizer l'I*Assumeoperating atthatlevelforsomeappreciable time.

TABLE3ARCSACTIVlTYMORKSMEEl NuclideElapseTimeShutdowntoSampleCountthoursMeasuredSpecificActivityCorrected OecayCorrection SpecificActivityRCSMassRCSActivityFactorCi/m~msCiKr85mKr87Kr88Xe131mXe133Xe133mXe13511311132I1331135Rb88Cs134Cs131Te129Te132Ba140La\40La142Pr144 TABLE38CONTAINHEHT SUHPACTIVITYWORKSHEET Huc1ideElapseTimeShutdowntoSampleCountthoursMeasuredSpecificActivityCi/msOecayCorrection FactorCorrected Containment Containment SpecificActivityWaterHassMaterActivity~IIISCiKr85mKr81Kr88Xe131mXe133Xe133mXe135I131I132I133I135Rb88Cs134Cs131Te129Te132Ba140La140La142Pr144 TABLE3CCONTAIHHEHT ATHOSPHERE ACTIVITYNDRKSHEET HucdeElapseTimeShutdowntoSampleCountthoursHeasuredSpecificActivityCorrected Containment Containment DecayCorrection SpecificActivityVolumeActivityFactor~CIccCCCiKr85mKrBTKr88Xe131mXe133Xe133mXe135I131I132I133I135Rb88Cs134Cs137Te129Te132Ba140La140La142Pr144 TABLE4DECAYCORRECTION FACTOR*WITHPARENT-DAUGHTER EFFECTNuclideCorrection FactorKr85mKr87Kr88Xe131mXe133Xe133mXe135I131I132I133Rb88Cs134Cs134Te129Te132Ba140La140La142Pr1440.158te'.547te0.248te(-3.59E-3)t 6(-2.45E-3)t 1/-01873.41E-2)t 0105.48E-3)t

+1287(-1.2E-2)t1/0103.41E-2)t 1111.28E-2)t 1/914(-1.04E-1)t 0033(2.67)t+10177.58E-2)t(3.59E-3)t e1/103'003(3.41E-2)t e0.104te110(0248t010234t1.01.01/109(-0.161)t 0167(-8.47E-4)t

-0257(0.605)t(8.92E-3)t e(2.26E-3)t e08(2e26E3)t008(1a72E2)t1/0145378)t114(0450)t1/0909102E4)t0091(2.41)t*Time,t,isthenumberofhoursbetweenshutdownandtimeofsamplecount.

TABLE5'ESTIMATE OFTOTALLIgUIOHASSl.Estimatethevolumeaddedforthefollowing:

Tanka.Refueling WaterStorageTankb.Accumulator Ac.Accumulator Bd.Accumulator Ce.Accumulator 0f.BoronInjection Tankg.SprayAdditiveTankh.OthersourceEstimated VolumeAddedMaximumVolume~d372,250-7,2637,2637,2637,2639004,000Totali.MeltedIceEstimated MassAddedHaximumHassAdded(ibm)2.7xl062.Convertestimated volumeaddedfromgallonstograms.Addedvolume:,gallonsx3785gms/gal=gms3.Converticemeltedmassfromibmtograins,ibmx454grams/ibm

=gms4.TheaverageReactorCoolantSystemMassis2.40x10gms.85.Oetermine theTotalLiquidMassasfollows:Massadded+RCSmass2.4x10gms=8gms+meltedicemassgmsgms

TABLE6KSTIHATEOF.RCSMATERHASS~ANDCONTAINHENT MATERHASSAVERAGEOPERATING RCSVOLUHE=ll,780ft31.Recordthereactorvessellevel,pressurizer1evel,andRCStemperature attimewhensamplewastaken.Reactorvessellevel=Pressurizer levelRCStemperature oF2.Determine RCSvolumeattime'ofsamplebyestimating fromlevelindications thepercentage ofwaterintheRCS.ftxX+1003.Determine RCSspecificgravityfromFigurel.RCSspecificgravity=4.Determine RCSmassasfollows:3~1.028.3x10cc3RCSvolume(ft)xspecificgravityx~xccft3ftx~1.028.3x10cc3xxccft35.RecordtheContainment Sumplevelindication andthecontainment levelindication.

Containment SumpLevel=Containment Level TABLE6(Continued)

ESTIMATEOFRCSWATERMASS*ANDCONTAINMENT WATERHASSrAVERAGEOPERATING RCSVOLUME=11,780ft,36.Determine containment watervolumefromFigures2and3usingthelevelsfromStep5.Note:Ifsumplevelindicates sumpisfulluseFigure3.Containment WaterVolume=7.Determine containment waterspecificgravityfromFigurel.Containment waterspecificactivity=8.Determine containment watermassasfollows:1.0m28.3x10cc3Containment watervolumexspecificgravityx'ccft3ftx1.0gm28.3x10cc3XXCCgms"Ifareactorvessellevelindication isnotavailable orisconsiderinaccurate basedonengineering judgments subtracttheestimated containment watermassfromtheestimated totalwatermass(Table5)todetermine RCSwatermass.TotalWaterHass=RCSmassgIllSgms-containment watermassgills TOTALRELEASEACTIVITY/PERCEHT RELEASED-UHIT1RCSContainment Containment TotalEquilibrium Corrected ActivitySumpActivityAtmosphere ActivityActivityCoreInventory*

PowerCorrection CoreInventory ReleasePercentage*

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.Thisnotationisusedthroughout theprocedure.

7**Release Percentage TotalActivitCorrected CoreInventory x100 TABLE78TOTALRELEASEACTIVITY/PERCENT RELEASED-UNIT2RCSContainment ActivitySumpActivityI~tueldeClCiContainment Atmosphere ActivityCiTotalActivityCiEquilibrium CoreInventory*

CiPowerCorrection FactorCorrected CoreInventory CiReleasePercentage" 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)**Release Percentage x100TotalActivitCorrected CoreInventory TABLE8POWERHISTORYOF30DAYSPRIORTOSHUTDOWNIntervalAveragePowerLevel*PjOperating PeriodatPjtjhoursPeriodBetweenendoftjandReactorShutdowntjhoursPowerCorrection FactorPCF**Stead-StatePowerCondition PCFTransient PowerCondition PCFI.Half-Life ofNuclide<1DaAveraePowerLevelHWtforrior4dasRatedPowerLevel(Hwt)-Xt-Lit'P(1-ej)eRatedPowerLevel(HWt)II.Half-LifeofNuc1ide>1DaAveraePowerLevelHWtforrior30dasRatedPowerLevel(Hwt)KP(1ejj)eijRatedPowerLevel(HWt)III.Half-Life ofNuclide-1YearAveraePowerLevelHWtforrior1earRatedPowerLevel(HWt)Effective FullPowerDasEFPDTotalCalendarDaysofCycleOperation

• 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 TABLE10COREOAMAGEASSESSMENT EVALUATION SHEETIndicator PercentCladDamaePercentOvertemeraturePercentFuelMelt<505>50%<50'A>505<50%>50$Radionuclide AnalsisKr85mKr87Kr88Xe131mXe133Xe133mXe135I131I132I133I135Cs134Cs137Te129Te132Ba140La140La142Pr144RatiosKr85m/Xe133Kr87/Xe133Kr88/Xe133Xe131m/Xe133 TABLE10(Continued)

CORE'AMAGE ASSESSMENT EVALUATION SHEETIndicator PercentCladDamaePercentOvertemeraturePercentFuelMelt505>505'50'g>50'A<50%>505Ratio(Con't)Xe133m/Xe133Xe135/Xe133I132/I131I133/I131I135/I131AuxiliarIndicators CoreUncovered CoreExitTemp'FContainment H5Zirc-WaterReaction5IgnitorsOn?HighRangeContainment MonitorReadingR/hr TABLE11NUCLIOEACTIVITYRATIOSNuclideGapFuelPelletActivitRatioCalculated ActivitRatio+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)

TABLE12CHARACTERISTICS OFCATEGORIES OFFUELOAHAGE*CoreOamageIndicator CoreOamageCategoryKocladdamage0-50KcladdamagePercentandTypeofFissionProductsReleasedKr-BT<lxl03Xe-133<lx1031-131<lx103I-133<lxl03Kr-81103-0.0)Xe-133103-O.lI"131103-0.31-133103-0.1FissionProductRatioHotApplicable Kr-BT0.0221-1330.11Containment RadiogasNonitor(R/hr)10hrsaftershutdown*"

0-660CoreExitThermocouples Readings(BegF)<750150-1300CoreUncoveryIndicationHouncoveryCoreuncoveryHydrogenHonitor(VolKHq)**~6PlantTypeNegligible 0-1350-100KcladdamageKr-810.01-0.02Xe-133D.l-0.21-1310.3-0.5I-1330.1-0.2Kr-810.022660to1325I-1330.711300-1650Coreuncovery13-2i0-50$fuelpelletovertemperature 50-100Kfuelpelletovertemperature 0-50$fuelmeltI50-IOOXfuelmeltXe-Kr,Cs,I

)-20Sr-Ba0-O.lXe-Kr,Cs,l 20-40Sr-BaO.l-0.2Xe,Kr,Cs,l 10-70Sr-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*Thistableisintendedtosupplement themethodology outlinedinthisreportandshouldnotbeusedwithoutreferring tothisreportandwithoutconsiderable engineering

)udgement.

• • Valuesshouldberevisedpertimesotherthan10hours."**Ignitorsmayobviatethesevalues.**@aKLOLLlRXe-133'-131

800.700.600.500~A400ClCl3008I-200~/oSTPFiGURE1MATEROENSITYRATIO(TEMPERATURE VSSTP) 90'0'O~50'0,30~20'p.0~'IOLVNE.Ft3FIGURE2SUMPWATERVOLUMEVERSUSSUMPLEVELINDICATION 90..80.70'460~CDCDICD50~40,20'DCDCDCD'NCDCDCDCDCDCDCDCDCQCDOCDCaCDCDCDCDCDCDCDCDCDFIGURE3CONTAINMENT WATERVOLUMEVERSUSCONTAINMENT LEVELINDICATION 1.00.990KPOWERO.e;RCORRECTION

-ACTOR75$POWER0.60.50.40.30.20.10.02004006008001000CYCLEOPERATION (CALENDAR

.DAYS)FIGURE4POWERCORRECTION FACTORFORCS-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)FIGURE5RELATIONSHIP OFXCLADDAMAGEWITH5COREINYENTORY RELEASEDOFKR-87 0.70.50.30'5OCP~02F01O~007.0050,1F07OlF05CJ~03///////re(a%eeo~ro+.003002.001lCV')Ill~~~~~i~~~~~~~IAh0000000~0000CVYlIhhQCladDamage(X)FIGURE6RELATIONSHIP OFXCLADDAMAGEWITHXCOREINVENTORY RELEASEDOFXE-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)FIGURE7RELATIONSHIP OFXCLADDAMAGEMITHXCOREINVENTORY RELEASEDOFXE-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)o0o0ocvneroFIGURE8RELATIONSHIP OF5CLADDAMAGEWITHXCOREINVENTORY RELEASEDOFI-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)FIGURE9RELATIONSHIP OFXCLADDAMAGEWITHXCOREINVENTORY RELEASEDOFI-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)FIGURE10RELATIONSHIP OF5CLADDAMAGEWITHXCOREINVENTORY RELEASEDOF1-132 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)FIGURE11RELATIONSHIP OFXCLADDAMAGEWITHXCOREINVENTORY RELEASEDOF,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)FIGURE12RELATIONSHIP OFXCLADDAMAGEWITHXCOREINVENTORY RELEASEDOF1-135 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)FIGURE12RELATIONSHIP OFXCLADDAMAGEWITH~COREINVENTORY RELEASEDOF1-135 100~70'0'0'0'0',53~re(D1CJo0.70~0~0~0~1OOFuelOvertemperature (X)FIGURE13RELATIONSHIP OF~~'UELOVERTEMPERATURE-WITH'XCOREINVENTORY RELEASEDOFXE,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)FIGURE14RELATIONSHIP OFXFUELOVERTEMPERATURE WITHXCOREINVENTORY RELEASEOOFBAORSR

)00'0.50'0~20'0'~5~ro+r*y~+rr2~0.7r0.0~0~O.llAh0O0ONhQFuelMelt(5)FIGURE15RELATIONSHIP OF5FUELMELTWITHXCOREINVENTORY RELEASEDOFXE,KR,I,CS,ORTE 100.010.01.00.10.011.010.0fuelMeItP)100.0FIGURE16RELATIONSHIP OFXFUELMELTWITH~oCOREINVENTORY RELEASEDOFBAORSR 100.010.01.00.10.010.0011.010.0FuelMelt(5)100.0FIGURE17RELATIONSHIP OF'X'FUELMELTWITHXCOREINVENTORY RELEASEDOFPR 30..25~20'5~UNIT2UNIT1///aaaaaaaaaaCVEOC)C'.aZIRC-MAl'ER REACt'ONPKRCc.Hf.hGKFIGURE18CONTAINMENT HYDROGENCONCENTRATION BASEDONZIRCONIUM WATERREACTION 100%NOBLEGASRELEASE52KNOBLEGASRELEAS0.3%NOBLEGASRELEASEANS18.1NORtQLOPERATING NOBLEGASRELEASE1.010.0100.01000.0TIMEAFTERSHUTDOWN(HOURS)FIGURE19PERCENTNOBLEGASESINCONTAINMENT FORUNIT1ANDUNIT2 APPENOIX8 EXAMPLEOFCOREDAMAGEASSESSMENT Thefollowing exampleis,presented toillustrate theuseofthisprocedure.

SIMULATED ACCIDENTSCENARIOForthisexample,Unit1hasexperienced anaccidentwheretheplant'smonitoring systemsindicated thatsafetyinjection hadinitiated andasignificant amountofwaterhadaccumulated inthecontainment.

Sampleswereavailable fromtheprimarycoolant(hotleg),thecontainment sump,andthecontainment atmosphere.

NUCLIDESAMPLINGSampleswerecounted6hoursafterreactorshutdown.

Theresultsofthesamplecountsarepresented inTables3A,38,and3C.Allsampleactivities reportedrepresent theactivityofthesampleatthetimeofanalysisandhavenotundergone adecaycorrection backtotimeofshutdown.

Thedecaycorrection factorsaredetermined fromTable4andrecordedinTables3A,3B,and3C.Thecorrected sampleactivities arethendetermined bymultiplying thesampleactivitybythecorrection factor.Thecorrected sampleactivities arerecordedinTables3A,3B,and3C.LIUIDMASSTable5wascompleted todetermine totalliquidmassavailable fordistribution intheRCSandcontainment.

All4accumulators haddischarged, theRNSThadsupplied350,000gallons,andtheboroninjection tank(900gallons)haddepleted..

Also,itisassumedthatalloftheicehadmeltedsupplying 2.7x10ibmofwater.Atotalwatermassof2.91x10gram69wascalculated.

Atthetimeofsampling, theRCStemperature was350'F,andthecontainment watertemperatture was150'F.Thereactorvessellevelindication systemwasnotfunctioning properlyattimeofsampling, andnoindication wasabletobe recorded.

Assuch,thecontainment waterwasthendetermined.

Thecontainment sumplevelindicated thesumpwasfullwhilethecontainment levelindicated an87'Xheight.rReferring toFigure3,87percentcorresponds toarangeofpossiblevolumesforthecontainment.

Acontainment watervolumeof98,000ftwasthenestimated bytakingtheaverageoftherange;98,0003ftofcontainment waterat1504Fcorresponds to2.77x10grams.398Subtracting thisfromthetotalwatermass,aRCSwatermassof1.4x10gramswasdetermined.

TheRCSandcontainment watermasseswererecordedinTable3Aand38,respectively.

TOTALACTIVITYRELEASEDThetotalactivityreleasedofeachnuclideforeachsamplelocationwasthencalculated bymultiplying thecorrected sampleactivitybythewatermassorcontainment volumeandrecordedinTables3A,38,and3C.ThesevalueswereagainrecordedinTable7A.Thetotalactivityofeachnuclidewascalculated bysummingtheactivityforeachsamplelocationandwasrecordedinTable7A.TOTALCOREINVENTORY Thepowerhistoryforthe30dayspriortoreactorshutdownwasrecordedinTable8.Thepowercorrection factorsforKr-87andI-132weredetermined bythesteady-state powercorrection equationFornuclidewithhalf-lives lessthan1day.Thepowercorrection factorsforXe-133,I-131,andBa-140weredetermined bythetransient powercorrection factorfornuclideswithhalf-lives greaterthan1day.ForCs-137,thetransient powercorrection factoruti.lizing effective fullpowerdaysofoperation duringthecyclewasused.Inthisexample,thecorehadoperatedfor240effective fullpowerdaysduringthe400daysofcycleoperation.

Thepowercorrection factorforCs-137is240EFPD400DaysThepowercorrection factorswererecordedinTable7A.

Thetotalcorrected inventory wasthencalculated bymultiplying theequilibrium coreinventory (listedinTable7A)bythepowercorrection factor.Thetotalcorrected coreinventory wasrecordedinTable7A.ESTIMATION OFPERCENTFUELOAHAGECompleting Table7A,thepercentage ofcorrected coreinventory releasedofeachnuclidewascalculated fromthecorrected activityreleasedandthecorrected coreinventory.

Thepercentreleasedforeachnuclidewasusedwiththeappropriate graphsofFigures4through16todetermine thecategoryandestimateofcoredamage.Estimates wereenteredinTable10undertheappropriate categories.

NUCLIOEACTIVITYRATIOSTablellwascompleted todetermine thenuclideactivityratios.TheratioswerecomparedtothegapandfuelpelletactivityratioslistedinTable11andthenrecordedinTable10undertheappropriate categories.

AUXILIARY INOICATORS Itwasdetermined thatthecorehaduncovered forapproximately 30minutesduringtheaccident.

Thecoreexitthermocouple readingsreached1750'F.ThesevalueswerecomparedwithTable12andrecordedinTable10undertheappropriate categories.

Thecontainment hydrogenmonitorindicated a4Xhydrogenconcentration, buttheignitorshadinitiated andsomehydrogenburninghadtakenplace.Thehighrangecontainment areamonitorindicated areadingof2.5E4R/hrat6hoursaftertheshutdown.

Comparing 2.5E4R/hrwithFigure18andTable12,thisvaluewasrecordedinTable10undertheappropriate categories.

COREOAHAGEASSESSMENT Alldatacollected inTab)e10wasevaluated toestimatetheextentofcoredamage.Thenuclidesanalyzedforthis.assessment wereKr-87,Xe-133,I-'131,I-132,Cs-137,andBa-140.Thenoblegases,iodine,andcesiumarereleasedduringallstagesofcoredamagewithBa-140beingacharacteristic fissionproductoffuelovertemperature andfuelmelt.BasedontheBa-140data,thedamagehadprogressed toapproximately 20$fuelovertemperature andminorfuelmelt(<1$).Thenoblegasandiodinedataindicated greaterthan100percentcladdamagehadoccurred.

However,itisrecognized thatinactuality thereisanoverlapbetweentheregimesofcoredamagestates.Thereleaseduetoovertemperature dominated thereleaseduetocladdamage,anditisestimated thatalargeamount{>50%)claddamagehadoccurred.

JTheauxiliary indicators supported theradionuclide analysis.

Thefactthatthecoreuncovered andthecoreexitthermocouples reachedaround1750'Fareindicative thatfuelovertemperature hadoccurred.

Thehydrogenconcentration of4X,wasinconclusive duetotheignitorsforcingsomehydrogenburns.However,thefactthattherewasasignificant amountofhydrogenproducedforburningtooccursupportstheassessment thatthecoreexperienced claddamageandfuelovertemperature.

Thehighrangecontainment areamonitorreadingsof3.5E4supportsthelessthan50$fuelovertemperature damagestate.Thus,forthisexample,thefinalfueldamageassessment isgreaterthan50%cladfailure,lessthan50Kfuelovertemperature, andthepossibility ofsomeveryminorfuelmelting(<lA).

TABLE1SELECTENUCLIDESFORCOREDAMAGEASSESSMENT CoreDamageStateNuclideHa1f-Life>Predominant GammasK'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.""Thesenuclidesaremarginalwithrespecttoselection criteriafor.candidate nuclides; theyhavebeenincludedonthepossibility thattheymaybedetectedandthusutilizedinamanneranalogous tothecandidate nuclides.

TABLE2SuestedSamlinLocations ScenarioPrincipal SamlinLocations OtherSamlinLocations SmallBreakLOCAReactorPower>lN*ReactorPower<1~+RCSHotLeg,Containment Atmosphere RCSHotLegRCSPressurizerRCSPressurizer LargeBreakLOCAReactorPower>1~*ReactorPower<l~+SteamLineBreakContainment Sump,Containment Atmosphere, RCSHotLegContainment Sump,Containment Atmosphere RCSHotLeg,RCSPressurizer Containment Atmosphere SteamGenerator TubeRuptureIndication ofSignifi-cantContainment SumpInventory RCSHotLeg,Secondary

.SystemContainment Sump,Containment Atmosphere Containment Atmosphere Containment BuildingRadiation MonitorAlarmSafetyInjection ActuatedContainment Atmosphere, Containment SumpRCSHotLegRCSPressurizer Indication ofHighRadiation LevelinRCSRCSHotLegRCSPressurizerAssumeoperating atthatlevelforsomeappreciable time.

TABLE3ARCSACTIVlTYWORKSHEET guJci~eElapseTimeShutdowntoSampleCounttoursHeasuredSpecificActivityDecayCorrection FactorCorrected SpecificActivityRCSHassRCSActivity~laSCiKr85mKrB>Kr88Xe131mXe133Xe133mXe1351131T132T133I135Rb88Cs134Cs137Te129Te132Ba140La140La142Pr144/.7(~)/.o(-3)/.DZg.03/.0/~.C)r-V(B)

TABLE38CONTAINHENT,SUHP ACTIVITYWORKSHEET ucideElapseTimeShutdowntoSampleCountthourHeasuredSpecificActivityOecayCorrection factorCorrected Containment Containment SpecificActivityWaterHassWaterActivity~SSCiKr85mKr87Kr88Xe131mXe133Xe133mXe135I131I132I133I135Rb88Cs134Cs131Te129Te132Ba140La140La142Pr144 TABLE3CCOHIAIHHEHT ATHOSPIIERE ACTIVITYWORKSHEET

+decideElapseTimeShutdowntoSampleCountourHeasuredSpecificActivityOecayCorrection Ci/ccFactorCorrected Containment Containment SpecificActivityVolumeActivityCiccCCCiKr85mKr81Kr88Xe131mXe133Xe133mXe135I131I132I133I135Rb88Cs134Cs131Te129Te132Ba140La140La142PrIhl TABLE4DECAYCORRECTION FACTORŽWITHPARENT-OAUGHTER EFFECTNuclideCorrection FactorKr85mKr87Kr88Xe131mXe133Xe133mXe135I131I132I133I135Rb88Cs134Cs134Te129Te132Ba140.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)t 1287{-1.28E-2)t 1/-0.10e'l.lie(-3.41E-2)t

{-1.28E-2)t 1/-9.14e'0.033e+10.17e{104E1)t(267)t1017(758E2)t(3.59E-3)t e1/1.03e'0.03e(892'E3)t003(307E1)t(3.41E-2)t e0.104te'/110248t-010(234)t1.01~01/1.09e'0.167e-0.257e(0'161)t847E4t-0257(0'605){8.92E-3)t e(2.26E-3)t e1/1.08e-0.08e(226E}t008(1'7)1/-0.145e

'1.145e1/0.909e'0.09le*Time,t,isthenumberofhoursbetweenshutdownandtimeofsamplecount.

TABLE5ESTIMATEOFTOTALLIgUIOHASSl.Estimatethevolumeaddedforthefollowing:

Tanka.Refueling WaterStorageTankb.Accumulator Ac.Accumulator 8d.Accumulator Ce.Accumulator 0f.BoronInjection Tankg.SprayAdditiveTankh.Othersourcei.MeltedIceEstimated VolumeAdded3~cocC~,z<3T7Z.CSav9,ps-Z.Estimated MassAddedQ.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.Oetermine theTotalLiquid.Mass asFollows:5'assadded/-//<~~gms+meltedicemass+RCSmass2.4x10gms=~-9lv/>8gms TABLE6ESTIHATEOF-RCSMATERHASS*ANOCONTAINHENT MATERMASSAYERAGEOPERATING RCSVOLUHE=11,780ft31.Recordthereactorvessellevel,pressurizer level,andRCStemperature attimewhensamplewastaken.Reactorvessellevel=Pressurizer levelRCStemperature oFIindice'A0>>s'y'5~.~nq>uori<inaQcao2.Oetermine RCSvolumeattimeofsamplebyestimating fromlevelindications thepercentage ofwaterintheRCS.ftxf+100=3.Oetermine RCSspecificgravityfromFigurel.RCSspecificgravity=4.Determine RCSmassasfollows:~1.028.3x10cc3RCSvolume(ft)xspecificgravityx'ccft3ftx3xx~1.028.3x10ccccft35.RecordtheContainment Sumplevelindication andthecontainment levelindication.

Containment SumpLevel=Containment Level/yOS7 TABLE6(Continued)

'IESTIMATEOF,RCSWATERMASS~ANQCONTAINMENT WATERMASSAVERAGEOPERATING RCSVOLUME=11,780ft36.Determine containment watervolumefromFigures2and3usingthelevelsfromStep5.Note:Ifsumplevelindicates sumpisfulluseFigure3.Containment WaterVolume=7.Oetermine containment waterspecificgravityfromFigurel.Containment waterspecificactivity=f~oP8.Determine containment watermassasfollows:3Containment watervolumexspecificgravityx'1.0m28.3x10ccccft31.0gm28.3x10cc3x-xCC3ftaZ-77~/5gms*Ifareactorve'ssellevelindication isnotavailable orisconsiderinaccurate basedonengineering judgments subtracttheestimated containment watermassfromtheestimated totalwatermass(Table5)todetermine RCSwatermass.TotalWaterPass+-~~~~~gms-containment watermass~.7><<~gmsRCSmass~-~~~<gms 1AT01ALRELEASEACTIVITY/PERCENT RELEASEO-UNIT1RCSContainment Containment TotalEqui)lbr1umCorrected ActlvltySumpActlvltyAtmosphere ActlvltyActlvltyCoreInventory*

PowerCorrection CoreInventory ii~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.Thisnotationlsusedthroughout theprocedure.

7>>ReleasePercentage TotalActlvltCorrected CoreInventory x100 TABLE78TOTALRELEASEACTIVITY/PERCENT RELEASEO-UNIT2RCSActivityg~ucl4~CContainment SumpActivity~CContainment Atmosphere ActivityciTotalEquilibrium Corrected ActivityCoreInventory*

PowerCorrection CoreInventory CICiFactorCiReleasePercentage*

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)**Release Percentage

~TotalActivitCorrected CoreInventory x100 TABLE8POWERHISTORYOF30DAYSPRIORTOSHUTDOWNInterval/ZAveragePowerLevel*P)zy37$2$0JC2~ZV37Operating PeriodatP~t~hoursxZfI'20.PeriodBetweenendoftgandReactorShutdownthours><8/"-/20PowerCorrection FactorPCF**Stead-StatePowerCondition PCFTransient PowerCondition PCFI.Half-Life ofNuclide<1DaAveraePowerLevelHWtforrior4dasRatedPowerLevel(Hwt)-l.t-X,it'P(1-e)eRatedPowerLevel(HWt)II.Half-Life ofNuclide>1DaAveraePbwerLevelHWtforrior30dasRatedPowerLevel(Hwt)-Xt-)it'P(1-ej~)eRatedPowerLeve](HWt)III.Half-Life ofNuclide-1YearAveraePowerLevelHWtforrior1earRatedPowerLevel(HWt)Effective FullPowerDasEFPDTotalCalendarDaysofCycleOperation

• 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 TABLE10COREDAMAGEASSESSMENT EVALUATION SHEETIndicatorPercentCladDamaePercentOvertemeraturePercentFuelMelt<50'A>505<505>505<505>50%Radionuclide AnalsisKr85mKr87Kr88Xe131mXe133Xe133mXe135I131I132I135Cs134Cs137-Te129Te132Ba140La140La142Pr144SC+g.gf-edRatiosKr85m/Xe133Kr87/Xe133Kr88/Xe133Xe131m/Xe133~0.2+

TASLE10(Continued)

COREDAMAGEASSESSMENT EVALUATION SHEETIndicator PercentCladPercentPercentOvertemerature..FuelMelt<50%>50K<50%>50'I<501>50%Ratio(Con't)Xe133m/Xe133Xe135/Xe133I132/I131I133/I131I135/I131AuxiliarIndicators CoreUncovered CoreExitTemp'FContainment H5Zirc-MaterReaction5IgnitorsOn?HighRangeContainment MonitorReadingR/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)

TABLEe12CHARACTERISTICS OFCATEGORIES OFFUELDAHAGE*CoreDamageIndicator CoreDamageCategoryPercentandTypeoFFissionProductsReleasedFissionProductRatioContainment RadlogasHonltor(R/hr)CoreExitThermocouplas Readings(DegF)CoreUncoveryIndication HydrogenHonltor(VolIIH2)"**6PlantTypeHocladdamage0-50%claddamage50-100Xcladdamage0-50%fuelpelletovertemperature 50-IDOLfuelpelletovertemperature 0-50XFuelmelt50-100XfuelmeltKr-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,l 1-20Sr-Ba0-0.1Xe-Kr,Cs, I20-40Sr-Ba0.1-0.2Xe,Kr,Cs,l 40-70Sr-Ba0.2-0.8Pr0.1-0.8Xe,Kr,Cs,l,Te

>70SrBa>24Pr>0.8HotApplicable Kr-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/s z.s~-P.mEW)3.$E5<750750-13001300-1650>1650>1650>1650>1650HouncoveryCoreuncoveryCoreuncoveryCoreuncoveryCoreuncovaryCoreuncoveryCoreuncoveryHag1iglble0-)313-2i13-2i13-2I73-2113-2I*Thistablelsintendedtosupplement themethodology outlinedconsiderable engineering

)udgement.

• • • lgnltorsmayobviatethesevalues.Xe-133'-131 lnthisreportandshouldnotbeusedIIlthoutreferring tothisreportandwithout/p'75jokers077prrg~ado~.>rz.

800.600.500'00'00200'/nSTPFIGURE1-WATEROEiNSITYRATIO(TEMPERATURE VS.STP) 90'0'5CDUJCDCDCI60'0-<0..30'0~i0.CDCDIC1CD41CDCDCDCDCDCClVOLUHE.Fl'3FIGURE2SUMPWATERVOLUMEVERSUSSUMPLEVELINDICATION 90..80..70'0'0~40,30'0'lOO'OClOCIOO0OOOOC7OOOOOOOOOAlET@ORE3'ONTAINMENT WATERYOLUMEYERSUSCONTATNMENT LEVEL.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(<)FIGOREGRELATIPNGHIP OFgCLAOOANAGEWITHXCOREINVENTORY

.RELEASEDOFKR-87 F70-0-0-0~tF07~0OlClQJ~0ClCC~0O070F007O'00rrgoF00F001CVF7aoa.a~I~hlY)IAha'00Olk1VlQ00Clad.Damage(5)FIGURE7RELATIONSHIP OFXCLADDAMAGEWITH'XCOREINVENTORY

--'RELEASED OFXE-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)hDFIGUREGRELATIONSHIP OFXCLADDAMAGEWITHSCOREIN~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.)Ah0FIGURE10RELATIONSHIP OFWCLADDAMAGENITHMCOREINVENTORY RELEASEDOFI-132 70.50'020-10'.5.3~r~4rrrr2~00~0~0~0~FuelOvertemperature (5)FIGUREZ3:RELATIONSHIP OF5FUELOVERTEMPERATURE MITH'ACOREINVENTORY RELEASEOOFXE,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)FIGURE14RELATIONSHIP OFSFUELOVERTEMPERATURE WITHXCOREINVENTORY RELEASEOOFBAORSR 10070-50'0'0~10'~3~2~ro+rprrrr0'0.0~0.0~1nsaOOOIllOOO'uelMelt(X)FIGUREIS,RELATIONSHIP OF'5FUELMELTNITHSCOREINVENTORY RELEASEDOFXE,.KR,I,CS,ORTE 0

100.010.00.10.011.0100'ueIMeIt.(5)100.0FIGURE'GiRELATIONSHIP OFEFUELMELTNITHSCOREINVENTORY RELEASED.

OFBAORSR JO.25~20"UNITia~UNIT5.C7C00C)OOC7OlYlVlCCIZlRC-QAI'P3 RE.BIGS'ION 1'KRCEHf.WGKFIGDREIBCONTAINMENT HYDROGENCONCENTRATION BASEDON'Z)RCONIUN MATERREACTION l005.NOBLEGASRELEASES2XNOBLEGAS;RELEAS0.3$NOBLEGASRELEASEANS.181NORMALOPERATING NOBLE'ASRELEASE'0..0..

100.01000.0TINEAFTERSHUTOOMN(HOURS)FIGUREZG-PERCENTNOBLEGASES'NCONTAINMENT

-.-FOR.UNIT.1ANOUNITP'