ML17229A571
| ML17229A571 | |
| Person / Time | |
|---|---|
| Site: | Saint Lucie  |
| Issue date: | 10/31/1997 |
| From: | ABB COMBUSTION ENGINEERING NUCLEAR FUEL (FORMERLY |
| To: | |
| Shared Package | |
| ML17229A570 | List: |
| References | |
| CENPD-387, NUDOCS 9801070057 | |
| Download: ML17229A571 (68) | |
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CENPD-387,St.LucieUnit2CriticalitySafetyAnalysisfortheSpentFuelStorageRackUsingSolubleBoronCredit.October1997PDRADOCK05000389980i07005797i23iPDRi'BB'ombustionEngineeringNuclearOperationsJIonrIeIr r
CENpD487TableofContentsTableofContents.ListofTables.ListofFigures.1.0Introduction1.1DesignCriteria.1.2DesignDescription.1.3AnalysisDescriptions2.0AnalysisMethods2.1SCALE-PC.................2.2TheDITCode.3.0SpentFuelPoolandStorageRack.3.1StorageRackDescription.....3.2SpentFuelStoragePattern.4.0CriticalitySafetyAnalysis.4.1AnalyticModelsoftheStorageRackandModuleCells..4.2K,aEvaluationatZeroSolubleBoron.4.3K,aEvaluationforSolubleBoronCredit.4.4ReactivityEquivalencing4.4.1BurnupandDecayTimeReactivityEquivalencing.4.4.2GadoliniumCreditReactivityEquivalencing.4.4.3SolubleBoronCreditforUncertaintiesinReactivityEquivalencing.4.5AxialBurnupDistribution.5.0PostulatedAccidents.6.0SolubleBoronCreditSummary.7.0References....'.....310121515161718..181921.....21..23..25262
CENp0487Figure1Figure2Figure3Figure4Figure5Figure6Figure7Figure8Figure9Figure10Figure11Figure12Figure13Figure14Figure15Figure16Figure17ListofFiguresSpentFuelStorageModuleInstallation.TypicalSpentFuelStorageRackModule..TypicalSpentFuelRackModuleL-Insert.L-Inserts.SpentFuelStorageModule.FuelAssembly.SpentFuelRackModuleForRegionISpentFuelRackModuleForRegionIISpentFuelLoadingPatternForRegionISpentFuelLoadingPatternForRegionIIRequiredFuelAssemblyBurnupvsInitialEnrichmentandDecayTimeRegionII,1.3w/o.RequiredFuelAssemblyBurnupvsInitialEnrichmentandDecayTimeRegionII,1.5w/o.RequiredFuelAssemblyBurnupvsInitialEnrichmentandDecayTimeRegionI,1.4w/o.RequiredFuelAssemblyBurnupvsInitialEnrichmentandDecayTimeRegionI,1.82w/oRequiredFuelAssemblyBurnupvsInitialEnrichment,RegionI,2.82w/o........K-InfinityAt5.0w/oWith90%GadWorth(Through60000Mwd/T).............:K-InfinityAt5.0w/oWith90%GadWorth(Through20000Mwd/T).........,........37....38....39....,4041424344454647484950515253 CENpo4871.0IntroductionThisreportpresentstheresultsofacriticalityanalysisfortheSt.LucieUnit2spentfuelstorageracktakingcreditforassemblyburnup,forsolubleboroninthespentfuelpool,forgadoliniumburnableabsorbersandforactinidedecay.ThemethodologyemployedinthisanalysisisanalogoustothatofReference1andemploysanalysiscriteriaconsistentwiththosecitedintheSafetyEvaluationbytheOfficeofNuclearReactorRegulation,Reference2.1.1DesignCriteriaThedesigncriteriaareconsistentwithGDC62,Reference3,andNRCguidancetoallPowerReactorLicensees,Reference4.Section2.0describestheanalysismethodsincludingdescriptionofthecomputercodesusedtoperformthecriticalitysafetyanalysis.Abriefsummaryoftheanalysisapproachandcriteriafollows.1.Determinethestorageconfigurationofthespentfuelracksusingnosolubleboronconditionssuchthatthe95/95K,iruppertolerancelimitofthesystem,includingapplicablebiasesanduncertainties,islessthanunity.2.Next,usingtheresultingconfigurationfromthepreviousstep,calculatethespentfuelrackeffectivemultiplicationfactorwiththechosenconcentrationofspentfuelpoolsolubleboronpresent.Thencalculatethesumof:(a)thelattermultiplicationfactor,(b)thereactivityuncertaintyassociatedwithfuelassemblyandstorageracktolerances,and(c)thebiasesandotheruncertaintiesrequiredtodeterminethefinal95/95confidenceleveleffectivemultiplicationfactorandshowthatatthechosenconcentrationofsolubleboron,thesystemmaintainstheoveralleffectivemultiplicationfactorlessthanorequalto0.95.3.Usereactivityequivalencingmethodologiestodeterminetheminimumfuelassemblyburnupforfuelassemblyenrichmentsgreaterthanallowedinstep1,above.Asafunctionoftimeafterdischargeandburnup,calculatethereactivitycreditduetoactinidedecayforeachfuelassembly.ForfuelassembliescontainingGdq03-UO2rods,evaluatereactivitycreditduetothelumpedburnablepoison.Includethesecreditsinthereactivityequivalencingforeachfuelassembly.4.Determinetheincreaseinreactivitycausedbypostulatedaccidentsandthecorrespondingadditionalamountofsolubleboronneededtooffsetthesereactivityincreases.1.2DesignDescriptionThe16xl6ABBCEfueldesigncharacteristicsaregiveninTable3.Thefuelpelletischaracterizedbythe"ValueAdded"concept,whichincludesaslightlyexpandedpelletdiameterandhigherfuelstackdensityrelativetopreviousdesigns.AllthespentfuelpoolreactivitycalculationsincludetheeffectofValueAddedpellets.NIkIkP%ININ
CENPD487TheSt.LucieUnit2spentfuelstorageracksaredescribedindetailintheUpdateFinalSafetyAnalysisReport(UFSAR),Reference5.ThesestoragerackscontainnosupplementalpoisonbeyondthestructuralmaterialsandtheL-insertsinRegionI.Section3.0andFigures1through10provideadescriptionofthestoragecells,storagemodulesandpoolconfiguration.1.3AnalysisDescriptionsTechnicalSpecificationsandtheUFSARlimitthepresentutilizationofthespentfuelstorageracktofuelassemblieshavinganinitialenrichmentof4.5w/oU-235arrangedinacheckerboardpatterninRegionIandtothreeoutoffourpositionsinRegionII.Thus,theprimaryobjectiveofthisanalysisofthespentfuelstoragerackistoobtainmoreef6cientutilizationoftheavailablestoragecapacityconsistentwiththelatestNRCapprovedmethodology,viz.,employingcreditforsolubleboron.Inaddition,theanalysespresentedinSection4.0andFigures11-17demonstratenotonlyasignificantincreaseintheutilizationofavailablestoragecellsbytakingcreditforactinidedecay,butalsothecapabilityforemployingU-235enrichmentlevelsupto5.0w/oinfuelassembliescontainingGadolinia-UO2rods.Section5.0presentstheadditionalboronrequirementstoprotectagainstseveralpostulatedaccidents:fuelassemblydrop,lossofspentfuelpoolcooling,andfuelassemblymisload.Section6.0presentsthecombinedsolubleboronrequirementsfromthisanalysis.
E~
CENPD4872.0AnalysisMethodsTheanalysismethodologyusedintheevaluationofthestorageconfigurationofthespentfuelstoragerackemploys:(1)SCALE-PC,apersonalcomputerversionoftheSCALE-4.3codepackagedocumentedinReference6,withtheupdated44groupENDF/B-5neutroncrosssectionlibrary,and(2)thetwo-dimensionalintegraltransportcodeDIT,Reference7,withanENDF/B-6neutroncrosssectionlibrary.SCALE-PCisusedforbothoverallstoragerackaswellassub-regiontypeK,Qcalculations;SCALE-PCmodulesemployedinboththebenchmarkinganalysesandthespentfuelstoragerackanalysesincludeCSAS-2,BON-AMI,NITAWL,andKENO-Va.TheDITcodeisusedforsimulationofin-reactorfuelassemblydepletionandspecifictypesofstoragecellcalculations.Thefollowingsectionsdescribetheapplicationofthesecodesinmoredetail.2.1SCALE-PCValidationofSCALE-PCforpurposesoffuelstoragerackanalysesisbasedontheanalysisofselectedcriticalexperimentsfromtwoexperimentalprograms.ThefirstistheBabcock0WilcoxexperimentscarriedoutinsupportofCloseProximityStorageofPowerReactorFuel,Reference8.Thesecond'programisthePacificNorthwestLaboratoryProgramcarriedoutinsupportofthedesignofFuelShippingandStorageConfigurations;theexperimentsofcurrentinteresttothisefFortaredocumentedinReference9.Reference10,aswellasseveraloftherelevantthermalexperimentevaluationsinReference11,werefoundtobeusefulinupdatingpertinentexperimentaldatadocumentedinReference9.Forpurposesofcodevalidation,nineteenexperimentalconfigurationswereselectedfromtheBOWexperimentalprogram.Theseconsistedofthefollowingexperimentalcores:CoreX,thesevenmeasuredconfigurationsofCoreX,CoresXIthroughXXI,andCoreXIIIa.Thisapproachfocusedonusingmeasuredratherthanextrapolatedconfigurationstoavoidintroducinganybiasesoruncertaintiesassociatedwiththeextrapolationtechniques.Thisgroupofexperimentalconfigurationsemployedvariablespacingbetweenindividualrodclustersinthenominal3x3array.Inaddition,theefFectsofplacingeitherSS-304orB/Alplatesofdifferentblacknessesinthewaterchannelsbetweenrodclustersweremeasured.Table1summarizestheresultsoftheseanalyses.Similarly,elevenexperimentalconfigurationswereselectedfromthePNLexperimentalprogram.Theseincludedunpoisoneduniformarraysoffuelpinsand2x2arraysofrodclusterswithandwithoutinterposedSS-304orB/AlplatesofdifFerentblacknesses.Table2summarizestheresultsoftheseanalyses.TheapproachemployedforadeterminationofthecalculationalbiasisbasedonCriterion2ofReference12.ForagivenKENOeigenvalueanduncertainty,themagnitudeofK9$/95iscomputedbythefollowingequation;bythisdefinition,thereisa95percentconfidencelevelthatin95percentofsimilaranalysesthevalidatedcalculationalmodelwillyieldamultiplicationfactorlessthanK~5~5.
CENPD487where:I/22K9//9$KKENolUCBM95/95(O+%KENO)K~goistheKENOmultiplicationfactorofinterest,LQ<Bisthemeancalculationalmethodbias,M95/95isthe95/95multiplierappropriatetothedegreesoffreedomforthenumberofvalidationanalyses,ais.themeancalculationalmethodvariancededucedfromthevalidation2analyses,anda~goisthestandarddeviationappropriatetotheKENOmultiplicationfactorofinterest.Theequationforthemeancalculationalmethodsbiasisasfollows.~=-g,(1-K)where:K;istheivalueofthemultiplicationfactorforthevalidationlatticesofinterest,andMq5;q5isobtainedfromthetablesinReference13.Theequationforthemeancalculationalvarianceoftherelevantvalidatingmultiplicationfactorsisasfollows.20avewherek'"'sgivenbythefollowingequation.a,isgivenbythefollowingequation.2 CENPD48FwhereG;isthenumberofgenerations.Forpurposesofthisbiasevaluation,thedatapointsofTables1and2arepooledintoasinglegroup.Withthisapproach,themeancalculationalmethodsbias,dXa,andthemeancalculationalvariance,(a),calculatedbyequationsgivenabove,aredeterminedtobe0.00259and(0.00288),respectively.ThemagnitudeofM95/9$isdeducedfromReference8forthetotalnumberofpooleddatapoints,30.ThemagnitudeofK~s~sisgivenbythefollowingequationforSCALE4.3KENOVaanalysesemployingthe44groupENDF/B-Vneutroncrosssectionlibraryandforanalyseswheretheseexperimentsareasuitablebasisforassessingthemethodsbiasandcalculationalvariance.K95/95K~yo+0.00259+2.22[0.00288+(axago)]Afullscalemock-upoftheSt.LucieUnit2spentfuelstoragearray,thatissixRegionIandthirteenRegionIIstoragemoduleswiththenominaltwo-inchinter-modulespacing,wasmodeledinKENO-Vaforbasicevaluationsofthecharacteristicsofthefuelassemblystoragerack.TheseKENOcalculationstypicallyemployedonemillionneutronhistories.DiFerentneutronstartingdistributionswereemployeddependinguponthetypeofcalculationtoensureconservativemultiplicationfactorswereemployedintheevaluations.Forsomecalculations,suchasthefuelassemblymisloadaccidentsinRegionI,asmallerrepresentationofthestoragerackwasemployedwhichconsistedofthewholeofRegionIplusonerowofRegionIImodulesalongtheinterfaceboundarybetweenthetworegionstomaintainamorecorrectrepresentationoftheboundaryconditionsforRegionI.AthirdclassofKENOcalculationsemployedindividualstoragecellrepresentationsforbothRegionIandIItypecells,thatismodulecellswithandwithoutL-inserts.CalculationswiththesetwogeometriesemployedbothfreshandburnedfuelrepresentationsoftheABB-CE16x16fuelassemblydesign.TheseinfinitearraystoragecellmodelshadthedisadvantageofastochasticcalculationbuttheadvantageofthehighlyflexibleSCALE-PCgeometrycapability.TypicalKENOcalculationswiththesecellsemployed500,000neutronhistories.Consequently,thepracticeofcalculatingdi6erences,inKirattheone-sigmalevelhadlittleimpactonthequantitativeresultsforcasesofimportance.
CENP04872.2TheDITCodeTheDIT(DiscreteIntegralTransport)codeperformsaheterogeneousmultigrouptransportcalculationforanexplicitrepresentationofafuelassembly.Theneutrontransportequationsaresolvedinintegralformwithineachpincell.Thecellsretainfullheterogeneitythroughoutthediscreteintegraltransportcalculations.Themultigroupspectraarecoupledbetweencellsthroughtheuseofmultigroupinterfacecurrents.TheangulardependenceoftheneutronfluxisapproximatedatcellboundariesbyapairofsecondorderLegendrepolynomials.Anisotropicscatteringwithinthecells,togetherwiththeanisotropiccurrentcouplingbetweencells,provideanaccuraterepresentationofthefluxgradientsbetweendissimilarcells.ThemultigroupcrosssectionsarebasedontheEvaluatedNuclearDataFileVersion6(ENDF/B-VI).Crosssectionshavebeencollapsedintoan89groupstructure,whichisusedintheassemblyspectrumcalculation.Followingthemultigroupspectrumcalculation,theregion-wisecrosssectionswithineachheterogeneouscellarecollapsedtoafewgroups(usually4broadgroups),foruseintheassemblyfluxcalculation.AB1assemblyleakagecorrectionisperformedtomodifythespectrumaccordingtotheassemblyin-orout-leakage.Followingthefluxcalculation,adepletionstepisperformedtogenerateasetofregion-wiseisotopicconcentrationsattheendofaburnupinterval.Anextensivesetofdepletionchainsisavailable,containing33actinidenuclidesinthethorium,uraniumaridplutoniumchains,171fissionproducts,thegadolinium,erbiumandborondepletableabsorbers,andallstructuralnuclides.Thespectrum-depletionsequenceofcalculationsisrepeatedoverthelifeofthefuelassembly.Severalrestartcapabilitiesprovidethetemperature,densityandboronconcentrationdependenciesneededforthreedimensionalcalculationswithfullthermal-hydraulicfeedbacks.TheDITcodeanditscrosssectionsethavebeenusedinthedesignofreloadcoresandextensivelybenchmarkedagainstoperatingreactorhistoryandtestdata.Forthepurposeofspentfuelpoolcriticalityanalysiscalculations,theDITcodeisusedtogeneratethefuelisotopicsasafunctionoffuelburnupandinitialfeedenrichment.TheseisotopicsareinputtoKENOtogeneratetheK-infinityvs.burnup,K-infinityvs.enrichment,andtheburnupvs.enrichmentcurves.Thecodeisalsousedtocalculateinputtothegadoliniumburnableabsorberreactivitycreditandtheactinidedepletionburnupcreditanalyses.10 CENPD48703.0SpentFuelPoolandStorageRackTheSt.LucieUnit2spentfuelstorageracksaredescribedintheUFSAR(Reference5).ThissectionprovidesamoredetaileddescriptionofthespentfuelstoragerackwiththeobjectiveofestablishingabasisfortheanalyticalmodelemployedinthecriticalityanalysisdescribedinSection4.0.Forpurposesofthiscriticalityanalysis,thevalue-addedfuelrodparametersofTable3wereused.3.1StorageRackDescriptionThespentfuelstoragerackandpoolenvironmentaredescribedinSection9oftheSt.LucieUnit2UFSAR.Figure1,acopyofUFSARFigure9.1-5,showsaplanarviewofthearrayofnineteenmoduleswithinthepool.Figures2and3(UFSARFigures9.1-2and9.1-3a)illustratedetailsofaRegionImodulewiththeL-insertspresent;notealso,theperimeterstripaboutthetopofthemodules.Figure4(UFSARFigure9.1-3b)showsmoredetailontheL-inserts.Themodulesinbothregionsarepositionedinthepooltoprovideaminimumseparationoftwoinchesbetweenadjacentmodules.Figure5(UFSARFigure9.1-4)providesoveralldimensionsandtolerancesonthefourbasicmoduletypes.kAclarificationonthedetailsoftheL-insertillustratedinFigure4iswarranted.Asnotedinthelatterfigure,theSS-304platestockemployedtoformtheL-inserthasanominalthicknessof0.188inches.TheoveralldimensionsoftheformedL-insertis8.740+0.000/-0.050inches,exclusiveofthelockingtabregionillustratedinFigures3and4.IncludedinthelatteroveralldimensionoftheL-insertisthedimensionandtoleranceoftheout-facingellipticaldimplesinthetwooutsidefacesoftheL-insert.Ninedimplesarespaced15inchesapartintheaxialintervaloftheL-insertspanningtheactiveportionofthefuelassembly;thedimplesinthetwofacesoftheL-insertareoffsetaxiallybyonehalfofthespacingpitch.TheheightofthedimplesabovetheoutsidesurfaceoftheL-insertisspecifiedas0.070+0.010inches.Asaconsequence,thenominalRegionIcellhasa0.070inchwatergapbetweenthemodulecellwallandtheoutsidesurfaceoftheL-insert.TogiveabetterperspectiveoftheverticaldimensioningofthecomponentsofaRegionImodulecell,theL-insertsareapproximately165incheslongandthemodulecellwallsareapproximately178incheshigh;thebaseofthefuelassemblyillustratedinFigure6(Figure4.2-6oftheUFSAR)restsonasupportplateapproximately5inchesabovethebaseofthemodulecell.RegionIofthestoragerackconsistsofsixmodules,two7x10andfour7x11storagemodules,containingatotalof448storagecells;eachmodulecellcontainsastainlesssteelL-insertwithinthecelltoprovideadoublewallregion,withaninterveningwaterregion,betweeneachstoragelocationasillustratedinFigure7(UFSARFigure9.1-5a).RegionIIofthestoragerackconsistsof13modules,one8x10andtwelve8x11modules,containingatotalof1136storagecells;eachstoragecellinthisregionhasasinglestainlesssteelwallseparatingadjacentstoragecellsasillustratedinFigure8(UFSARFigure9.1-5b).ILIIlkP%ININ CENPD487Sincethebasicmodulecellsareofthesamenominaldimensionsineachmoduletypeinbothregionsofthestoragerack,thenominalRegionIstoragecellhasasmallerinternalareaduetothepresenceoftheL-insertdevice.Themonolithicstructureofeachmoduleisformedbyweldingthe178inchlongjuncturebetweensquarerightangleandslabcomponentsformedfrom0.135-inchthickplatestock.Theresultingcellshaveinternaldimensionsof8.740+0.180/-0.000inches.Overalldimensionsonthemonolithicstructure,includingthe7/16inchperimeterstripatthetopofthemodule,areshowninFigure5.Theoveralldimensionsarekeyedtothenumberofcellsalongasideofthemoduleas100+I/2,91+1/2,73+1/2,and64+1/2inchesforthe11,10,8,and7unitcelldimensions.3.2SpentFuelStoragePatternThespentfuelstoragepatternisdepictedinFigure9forRegionIandFigure10forRegionIIasanarrayoftheequivalentuniformenrichmentfuelassemblies.ItisnotedthatforRegionIthereare172watercelllocationswhereasinRegionIIthereare52.InRegion'II,thefourwatercellswithineachmodulearelocatedinasymmetricpatternrelativetothecornersofeachmodule.InRegionI,thewatercelllocationsarepositionedquitedifferently.Thereareeightclassesoffueltypesthatmaybestoredinthespentfuelstoragerack;threeclasses,ofthesefuelassemblytypesemployControlElementAssemblies(CEAs)assupplementalreactivityhold-downdevices.Thefuelassemblyclassesaresummarizedasfollows:1)2)3)4)5)6)7)8)9)RegionII:1.3w/oU-235equivalent,RegionII:1.5w/oU-235equivalent,RegionI:4.5w/oU-235equivalent,RegionI:4.5w/oU-235equivalentwithCEAinserted,RegionI:5.0w/oU-235equivalentwithGd.poisonrods,RegionI:5.0w/oU-235equivalentwithGd.poisonrodsandCEAinserted,RegionI:2.82w/oU-235equivalentwithCEAinserted,RegionI:1.82w/oU-235equivalent,andRegionI:1.4w/oU-235equivalentAllevaluationsinthisreportemploythemorereactivevalue-addedfuelrodtype,consequentiallythereisnodifferentiationbetweenthestandardandvalue-addedfuelassemblytypes.Inaddition,themorereactivefuelassemblyclasseslistedabovewereemployedinthecriticalityanalysisforthespentfuelrack,i.e.classes1,2,3,8and9..Asnotedintheabovetabulation,onlytwooftheeightfuelclasses,viz.,the1.3and1.5w/oequivalentenrichmentfuelassemblyclassesaredesignatedforstorageinRegionIIofthestoragerack.TheremainingsixclassesarerestrictedtoRegionI.RegionIIisarrangedasfollows:~The1.3w/oenrichmentequivalentfuelassemblylocationsinRegionIIareshownasthedarksquaresinFigure10(Class1).iLMINPRISSY12 CENP0487ThegrayperipheralsquaresandthefourinboardlocationsalongtheinterfacebetweenRegionsIandIIarethe1.5w/oenrichmentequivalentlocations(Class2)Thewhitesquareslocatedthreepositionsinboardfromthecornerpositionofeachmodulearethewatercelllocations.ThefuelassemblytypesdepictedinFigure9forRegionIarethe4.5w/oenrichmentequivalentfuelassemblieswithandwithoutCEA's,andthe1.82and1.4w/oenrichmentequivalentfuelassemblies.RegionIisbestdescribedasanannularconfigurationoffuelassemblytypes.Progressingfrominsidetooutside:Thecentral3x10arrayofdarkbluesquaresadjacenttotheboundarybetweenRegionsIandIIconsistsof1.4w/ofuelassemblies(Class9).Thenextringofmediumbluecellsconsistsof1.82w/ofuelassemblies(Class8).Thenextringofcellsiswatercells.Theringbeyond,duetolackofanoddnumberofcelllocations,consistsofelevenlightbluecellswith5whitedotswhichare4.5w/oassemblieswithoutCEAs(Class3),14watercells,andonemediumblue1.82w/oassembly(Class8).Thelatterassemblyfillstheonlyinsidecornerlocationinthisrownotoccupiedbyawatercell.Thenextringofcellsconsistsof1.82w/oassemblies(Class8)Thenextringisallwatercells.Thenextdoubleringofcellsconsistsof1.82w/oassemblies(Class8)withtheexceptionofthetwowatercellsinboardtotheoutsidecornerlocations.NextisathirdlayerofwatercellsThisisfollowedbyaringof4.5w/oassembliesalternatingbetweenthosewithCEAs(Class4)andthosewithoutCEAs(Class3).CellswithoutCEAs(Class3)have5lightdots.Lackofanoddnumberofcellsagaindictatedamixedarrayinthisring.Thetwocornerlocationsareoccupiedby4.5w/oassemblieswithoutCEAsasarealternatingstoragelocationsinbothdirectionsawayfromthecornerexceptnearthecenterofthemiddle-uppermodule.Hereitwasnecessarytoinserttwo1.82w/oassemblies(Class8)tocontrolthelocalK.Thefourthandoutermostringofwatercellsfollows.Anarrayoffuelassemblyenrichmentsnearlyidenticaltothepreviousonewasemployedintheoutermostringoffuelassemblies.Ithas8moreassemblieswhichmerelyextendthealternatingpattern.Theremainingclassesoffuelassemblytypesnotaddressedinthelastparagraphareasfollows.A2.82w/oequivalentenrichmentfuelassemblywithafullstrengthCEAinserted(Class7)maybeinterchangedwitha1.82w/oequivalentenrichmentfuelassembly(Class8)sincetheformerislessreactivethanthelatter.Inasimilarvein,a5.0w/oU-235enriched,gadoliniumshimmedfuelassemblyhavingagadoliniumloadingofthetypespecifiedinSection4.4.2(Class5)orthesamefuelassemblycontainingafullstrengthCEA(Class6)arelessreactivethantheir13 1,
CENp0487unshimmed4.5w/oequivalentenrichedfuelassemblycounterparts(Class3and4,respectively).
CENpo4874.0CriticalitySafetyAnalysis4.1AnalyticModelsoftheStorageRackandModuleCellsSection3.1providedadescriptionofthespentfuelstoragerack.UsingthedataofSection3.0,analyticmodelswerecreatedinbothSCALE-PCandDITtoperformthequantitativeevaluationsnecessarytodemonstratetheeffectivemultiplicationis:1)lessthanunitywithzeroboronpresentinthepool,and2)lessthanorequalto0.95whencreditistakenforsolubleboron.Applicablebiasestobefactoredintothisevaluationare:1)themethodsbiasdeducedfromthevalidationanalysesofpertinentcriticalexperiments(describedinSection2),and2)anyreactivitybias,relativetothereferenceanalysisconditions,associatedwithoperationofthespentfuelstoragepooloverthetemperaturerangeof50to155F.Asecondallowanceisbasedona95/95confidencelevelassessmentoftolerancesanduncertainties.Includedinthesummationofvariancesarethefollowing:a)the95/95confidencelevelmethodsvariance,b)the95/95confidencelevelcalculationaluncertainty,c)toleranceduetoenrichmentuncertainty,d)toleranceduetoUO2stackdensity,e)toleranceduetouncertaintyinL-insertandmodulewallthickness,toleranceduetouncertaintyinpositioningthefuelassemblyinthestoragecell,g)toleranceduetostoragecellIDandpitch,andh)the95/95confidencelevelassessmentofcalculatedCEAworth.Itemsa)andb)arebasedonthemethodsvalidationanalyses.Itemh)isbasedoncomparisonsofCEAworthmeasurementsandanalysesonoperatingreactorsaswellasexcellentagreementbetweenDITandKENO-VacalculationsofCEAworth.Foritemc),theuncertaintyinenrichmentistakentobe&.05w/o.Assessmentsofthemagnitudeofchangeinmultiplicationfactorper0.05changeinenrichmentmaybebasedoneitherinfinitearraysofagiventypeofstoragecellsorachangeintheoverallstoragerackeffectivemultiplicationfactorforachangeof0.05w/ointheequivalentenrichmentofagivenfuelassemblytype.Thecriticalityanalysisevaluationisdoneatanenrichmentof4.50w/o,i.e.attheuppertolerancelimitonenrichment,foraddedconservatism.Stackdensitywastakentobethekeyvariableforitemd)sincethisvariableismostpertinenttomeasuredparametersinthefuelmanufacturingoperation.Pelletstackcolumnweightandstacklengtharethetypicalmeasuredparametersforeachfuelrodandarecarriedforwardintotheas-builtfuelevaluations.Avaluefortheuncertaintyinthisparameterof2%wasassumed;thismagnitudeisconservativecomparedtoobservedhistoryofvariationsinthisparameter.iLNIk/%ISIS15 CENP0487Foriteme),thefollowingapproachwastaken.Thetolerancesonthethicknessofthe0.135inchthicksheetstockemployedforthemonolithwallstructureandthe0.188inchthicksheetstockemployedfortheL-insertweretakentobe+0.005inchesbasedonthemanufacturingdrawings.Foritemf),infinitecellarraysofbothRegionIandIItypecellswereexamined.Thefuelassemblieswerenormallyassumedtobecenteredwithineachstoragecelltypeforthenominalcalculations.Whenthefuelassemblywasmoveddiagonallyoff-centerinbothRegionIandIItypecells,thearrayreactivitydecreased.Consequently,thetoleranceforthisparameterwastakentobezero.Foritemg),thetoleranceduetostoragecellKDandpitchwereevaluatedinacombinedmannerusingthefollowingapproach.AnyassessmentoftolerancesoncellpitchandIDduetotolerancesonindividualcomponentswouldappeartobeoflittlerelevanceduetothemethodofassemblyofthemonolithicstructures.Itwasforthisreasonthatoveralldimensionaltoleranceswereimposedonthefinishedmodules.Sincethefinishedmoduleswerefoundtomeetthespecifieddimensionaltolerances,thesevaluesweretakentobethemorerelevantmeasureofthedimensionalvariationswithinagivenmodule.Ifonetakesthenominaloveralldimensionandsubtractsthethicknessofthetwoperipheralstripsaswellasthethicknessofonemoduleboxwall,anominalcellpitchof8.999inchesisobtainedforeachcellineachmoduletype.ThenominalcellIDis8.999-0.135or8.864inches.Themin/maxIDofthemodulecellwouldbebestapproximatedbythetoleranceontheinternaldimensionofthe0.135inchthickangleplates,viz.,min/maxID=8.74/8.920inches.FortheRegionIcells,thenominaldimensionsaredeterminedasfollows.TheexternaldimensionsoftheL-insertarelistedas8.740+0.000/-0.050inches.Thus,anominaldimensionedL-insertwouldhavesomeclearancewheninsertedintoanominalmodulecell.ThenominalIDoftheRegionIcellwastakenastheaverageofthemin/maxIDdeterminedbyassumingtheL-insertwasdisplacedfirsttotheleftandthentotherightextremesinthenominalmodulecell.ThenominalRegionIcellwasevaluatedas8.56inches.TheminimumIDoftheRegionIstoragecellisdefinedastheminimumoveralldimensionoftheL-insertminustheheightofthedimpleandthicknessoftheL-insertwallattheirlow'ertolerancelevel.TheminimummodulecellIDistakentobetheminimuminternaldimensionoftheangleplatesorsquareelementsformedfromthe0.135inchthickplatestock,viz.,8.740inches.4.2K.fiEvaluationatZeroSolubleBoronThefullfuelassemblystoragerackwasmodeledinKENO-VausingthefuelassemblystoragepatternofSection3.2.ThisKENOcalculationservedtoestablishareferencemultiplicationfactorat50'Fwithzerosolubleboroninthepoolwater.Theeffectivemultiplicationfactorforthesystemisevaluatedforthreeassumedinitialstartingneutronsourcedistributions:(1)auniformdistributionoverRegionII,(2)auniformdistributionoverRegionI,and(3)auniformdistributionoverbothRegionsIandII.TheK,irresultsareasfollows.Ai%INP%ISINSourceRegionIIRegionIRegionsI+II0.9700120.000520.96590+0.000540.96731+0.0005016 0
CENP0487ThehighestvalueofK,irisobtainedwithastartingneutrondistributioninRegionII;thisvalueistakentobethenominalvalueforthezeroboronconditionsinceitisthemostconservativeinterpretationofthedata.Inreality,therelevantsourcedistributionforaspentfuelstoragerackisonethatischaracteristictothespontaneousfissiondistributionandthisdistributionwouldfavorthemorehighlyburnedfuelregionofthestoragerack.ForpurposesofevaluatingtolerancesanduncertaintiesassociatedwithenrichmentandUO2stackdensity,perturbationsintheseparametersweremadeinthefullpoolKENOmodelwhereas,forcellwallthicknessesandcellIDandpitch,aninfinitearrayofRegionIorIIstoragecelltypeswasused.TheCEAworthallowanceisevaluatedbycalculatingtheCEAworthinafullpoolKENOcalculationandmultiplyingbyaconversionfactortoderivethe95/95confidenceleveluncertaintyinCEAworth.Table4liststhederivedquantitiesandthemargintounityforthenosolubleboroncondition.4.3K,iiEvaluationforSolubleBoronCreditTodeterminetheamountofsolubleboronrequiredtomaintaintheeffectivemultiplicationfactorlessthanorequalto0.95,aKENOcalculationofthefullstoragerackisemployedtoestablishanominalreferencemultiplicationfactorat50'F.Thecalculationofbiasesandtolerancesanduncertaintiesfollowedthesameproceduresasforthenosolubleboroncondition.Table5liststhederivedquantitiesandthemarginto0.95for350ppmsolubleboron.Thefinalsolubleboronrequirementisthesummationofthesolubleboroncreditrequirementsdeterminedinsteps2,3,and4ofSection1.Theserequirementsarestatedbythefollowingequation.where:SBCToTAi.=SBCg5as+SBCRa+SBCpASBCToTAi.=totalsolubleboroncreditrequirement(ppm).SBCesessolubleboroncreditrequiredfor95/95K,irtobelessthanorequalto0.95(ppm).SBCRasolubleboroncreditrequirementrequiredforreactivityequivalencingmethodologies(ppm).SBCpAsolubleboroncreditrequiredforK,irtobelessthanorequalto0.95underaccidentconditions(ppm).Thetotalsolubleboroncreditrequirementalongwiththestorageconfigurationspecifiedinthenosolubleboron95/95K,ircalculationshowsthatthefuelrackK,irwillalwaysbelessthanorequalto0.95.Furthermore,thenosolubleboron95/95K,irstorageconfigurationwillensurethatK,iiremainslessthan1.0withnosolubleboroninthespentfuelpool.17 CENP048704.4ReactivityEquivalencingReactivityequivalencingisausefulstrategyfordefiningtheconditionsunderwhichfresh,burned,andshimmedfuelassembliesareinterchangeableonanoverallreactivitybasis;othercharacteristicsoftheresultinglatticearrangementmaydiffer.ThisstrategyisusedtotranslatethearrayoffuelassembliesofdifFeringenrichmentsdefinedforthezerosolubleboronconditioninagivenspentfuelrackintoanarrayofburnedfuelassembliesofdifFeringinitialenrichments,decaytimes,andpossibleinitialburnablepoisoncompositions.4.4.1BurnupandDecayTimeReactivityEquivalencingSection3.2,above,definedtheenrichmentlevelsofthevariousfuelassembliesarrangedinthespentfuelstoragerackunderthezerosolubleboroncondition.Toestablishareactivityequivalencebetween,forexample,adepletedunshimmedfuelassemblyhavingauniforminitialUO2enrichmentof4.5w/oU-235andthe1.3w/oU-235fuelassemblystoredinRegionIIof.thestoragerackrepresentationforthezerosolubleboroncondition,twosets'ofdataaregeneratedwithintheenvironmentofaRegionIIstoragecell.First,theKoftheRegionIIstoragecellcontainingthe1.3w/oU-235fuelassemblywascalculatedbyKENOundertheappropriatecoolanttemperatureandsolubleboronlevels.Next,theKoftheRegionIIstoragecellwascalculatedbyKENOforfuelnuclidecompositionsappropriatetovariousfuelassemblyburnuplevelsforfuelassembliesofdifFerentinitialfreshfuelenrichmentsandunderthesamecoolanttemperatureandsolubleboronlevel.ThelatterburnedfuelnuclidecompositionsweregeneratedbyaDITsimulationofanoperatingreactor.Conservativefissilenuclidecompositionsversusburnupwereobtainedbydepletingthefuelatthereactoroutletmoderatortemperature.TheburnupatwhichtheKofthedepletedassemblymatchestheKofthe1.3w/ofreshassemblyistheminimumrequiredburnup.Thisprocessisrepeatedforeachcelltypepresentinthepool.Ifburnablepoisonshimsareemployedinthefuelassembly,thisfeaturemustalsobefactoredintotheinitialcompositionandnuclidecompositionasafunctionofburnupforthisassembly.I-135andXe-135decayPm-149decayintoSm-149Np-239decayintoPu-239ThenoXenon,peakSamariumandpeakPu-239conditionwasusedforthedeterminationofthestoragerackreactivitywithoutcreditforactinidedecay.Subsequently,thedecayoflongerhalf-lifenuclidescomesintoplay,themostimportantofwhichisthedecayofPu-241intoAm-241.Pu-241isafissilenuclidewhichcontributesseveralpercentofpositivereactivityathighburnup.Am-241,ontheotherhand,ismostlyanabsorberwhichhasanegativereactivitycomponent.ThehalflifeofPu-241being14.4years,itsdecayoverthelifetimeofthepoolstorageisimportantandcontributestoadecreaseinKoftheburnedfuelblyinthestoragecellenvironment.ThiseffectisfavorablesinceitreducesthepoolassemfLllIkP%NII18Followingdischargeofagivenfuelassemblyfromthereactor,thedecayoffissionproductsandactinidenuclideswithinthefuelwillinduceachangeinequivalentKoftheburnedfuelassembly.Withinthefirstfewdaysaftershutdown,alargeincreaseinKwillresultfromdecayofthefollowingnuclides:
CENP048Treactivityandmaypermitthetransferofdecayedburnedfuelassembliesintopositionsdesignatedforhigherburnupinthenosolubleboroncorerepresentation.BesidesPu-241,decayofalltheactinidesandfissionproductspresentintheDITmodelwasaccountedfor.Creditforactinidedecayisusedtoreducetheminimumburnuprequiredtomeetthereactivityrequirements.ActinidedecayefFectswerecalculatedoveratimeintervalofuptotwentyyearsforan.initialfeedenrichmentrangeofupto4.5w/oU-235inthefollowingmanner.First,isotopicsinthedepletedassemblywerecalculatedbyperformingaDITdepletionundernominaloperatingconditions,butatthereactoroutletmoderatortemperaturetomaximizetheconversionratioandthus,thereactivity.Atselectedtimepoints,depletedisotopicsweretransferredintoanotherDITmodelwhichrepresentsthegeometryofaspentfuelpoolcell,at50'Fand0PPMboron.Thismodelwasthendecayedfor20years,andthereactivitylosswithtimewastranslatedintoaburnupcreditusingtheburnupvs.enrichmentcurves.Tables6-1to6-4summarizethederivedburnup-enrichmentpairdata,includingcreditforactinidedecayfrom0to20years.Theseminimumburnupdataaretabulatedforfeedenrichmentsbetween1.5and4.5w/oU-235andforeachburnedfuelpositiontypeinthespentfuelpool.TheseresultsarealsoplottedinFigures11-15.4.4.2GadoliniumCreditReactivityEqulvalencingTheSt.LucieUnit2maximumenrichmentiscurrentlysetat4.5w/o.Thisenrichmentissetinpartbythespentfuelpoolcriticalityanalysis,whichassumesagivenloadingpatternforthefreshfuelassemblies.Thecriticalityanalysiswasperformedwithoutcreditfortheburnableabsorberreactivityhold-downofthefreshassemblies,thatis,itwasperformedasifallfreshassemblieswereunshimmed.Ifburnableabsorberreactivityhold-downisconsidered,thenthefreshfuelenrichmentcanbeincreaseduntiltheassemblyreactivitymatchesthatofanunshimmed,4.5w/oassembly.Theenrichmentcreditwasdeterminedforthefollowingfivediferentgadoliniumburnableabsorber(BA)loadings.NoofGadBARods4812816Gadloading(w/o)44466Thereactivitygainduetotheincr'easedenrichmentallowedbythegadoliniumcreditmustbeequaltoorlessthanthereactivityhold-downofthegadoliniumburnableabsorbersuchthatthefreshassemblyreactivityneverexceedsthefreshunshimmed4.5w/oassemblyreactivity.The.reactivityhold-downoftheburnableabsorberdependsonthenumberandloadingofthegadoliniumbearingrods,andalsooftheaxialcutbackoftheburnableabsorber.TheshortneutrondifFusionlengthincoldwatermagnifiestheimportanceofthecutback.19 CENPD487Theinitialreactivityhold-downanddepletioneffectswerefirstevaluatedinatwodimensionalgeometry,neglectingtheeffectofthecutback.Theinitialreactivityhold-downofthelightestGadoliniumloading(4rodsat4w/oGd)islargerthanthereactivitygainobtainedbyincreasingtheenrichmentfrom4.5w/oto5.0w/o.Theenrichmentofthegadoliniumassemblieswasassumedtobe5.0w/o,consistentwithguidanceintheSERcontainedinReference2.TheKofthepoisonedsectionofagadoliniumshimmedfuelassemblyislowerthanthatofauniformlyenriched,5w/ofuelassembly.Asthegadoliniumdepletes,theassemblyKwillapproachthatofacomparablyburned5.0w/ounshimmedassemblyand,atagivenburnup,willcrossthereactivityrundownofa4.5w/ounshimmedassembly.Foreachgadoliniumassemblytype,adepletionwasperformedat5.0w/o,andtheKvaluescomparedtothoseofanunshimmed4.5w/oassemblydepletion.TheassemblycharacteristicsaresummarizedinTable7.TheU-235contentofthegadoliniumshimrodsisreducedduringfabricationoftheserodstoensurethattheyarenotlimitingatanytimeduringthecycle.Thereducedgadoliniumpindensityreflectstheuraniumdisplacementbygadolinium.ThefuelassemblydepletioncalculationswereperformedwiththemultigrouptransportcodeDIT.TheK'fthevariousGadoliniumfuelassemblytypesisplottedinFigure16.A5.0w/ounshimmedassemblyisincluded.Tocoverpossibleuncertaintiesinthegadoliniumworthanddepletionrate,thegadoliniumreactivityhold-downwasreducedby10%forconservatism,leadingtoconservativelylowequivalentburnup.Beyond20,000MWD/T,thegadoliniumiseffectivelyfullydepletedandthereactivityoffsetisduetotheslightdifferenceinassemblyaverageenrichmentsandgadoliniumresidualworth.Figure17presentsthesamedataatanexpandedscale.BecausetheKofagadoliniumassemblyenrichedat5.0w/oU-235isalwayslowerthanthatofafresh4.5w/ounshimmedassembly,thegadoliniumassembliescanalwaysbestoredinthelocationsreservedforfresh,4.5w/ounshimmedassemblies.Theimpactofthegadoliniumcutbackwasdeterminedbyperformingathree-dimensionalKENOcalculationofRegionI,assigninga10.5inchcutbacktothe5.0w/ofreshassembly,andcomparingthereactivitytothatofareferencecasewithoutgadolinium,withafreshfuelenrichmentof4.5w/o.Atthelowestgadoliniumloading(4rodsat4w/oGd),thereactivitiesofthepoisonedcaseandofthereferencecaseareequal,indicatinganexactcompensationbetweenthenegativeworthofthecutbackburnableabsorberandthepositiveworthoftheincreasedenrichment.Attheheaviestgadoliniumloading(16rodsat6w/oGd),thereactivityofRegionIisreducedby0.0014~belowthereferencecase.ThesmallsensitivityofRegionItoreactivityperturbationsinthefreshfuelisconsistentwithearlierfindingsthattheimportanceofthefreshfuelissmall(everyotherassemblyisroddedandtheassembliesareseparatedbyarowofwatercells).Theimpactofthegadoliniumcutbackfordepletedassembliesisnegligiblebecauseofthehighburnuprequirementimposedbytheburnupvsenrichmentcurves,andbythelargeconservatismincludedintheaxialburnupdistributioneffects.ALi%I20 CENP0487AsshowninFigure16,theburnupdependenceofKisnearlyparallelforallassemblytypesbeyond20,000MWD/T.Theoff-setbetweenthevariousgadoliniumassembliesanda4.5w/ounshimmedassemblyis:GadAssemblyBurnupOF-set40003800360036003000BurnupOF-setBurnupOF-set@25,000MWD/T@45,000MWD/T4Gad4w/o365040008Gad4w/o3400380012Gad4w/o325036008Gad6w/o3250360016Gad6w/o27003000TheburnupofaGadoliniumfuelassemblyenrichedat5.0w/oU-235mustbereducedbythefollowingamountbeforeapplyingtheburnupequivalencingofTables6-1to6'-4fora4.5w/ounshimmedassembly:GadAssembly4Gad4w/o8Gad4w/o12Gad4w/o8Gad6w/o16Gad6w/o4.4.3SolubleBoronCreditforUncertaintiesinReactivityEquivalencingSolubleboroncreditforreactivityequivalencingincludestwoefFects:(1)anallowanceforpossibleuncertaintiesintheanalyticaltechniquesemployedtodefinetheburnedcompositionofthefuelassembly,and(2)anallowanceforpossibleuncertaintiesininferringtheburnupofagivenfuelassemblyremovedfromthecore.TheallowancefortheformeruncertaintyistakentobedX=0.005absolutereactivityper30,000MWD/Tand,forthelatterinferredburnupuncertainty,5%inburnup.Theboronworthfortheseallowancesisevaluatedunderthehighestburnupimposedonafuelassemblyhavinganinitialenrichmentof4.5w/oU-235.4.5AxialBurnupDistributionSeveralreactivityefFectsareassociatedwiththeaxialburnupdistribution.ThehigherfissilecontentnearthetopoftheassemblyincreasesitsKandresultsinatoppeakedfluxdistribution,whilethesteepfluxgradientresultingfromthetoppeakedfluxdistributionincreasestheaxialleakageandreducestheassemblyK,ir.TheseeFectswereevaluatedbycomparingtheresultsof2-and3-dimensionalcalculationsofassemblyreactivityat68'F,0PPMboron,andnoxenonasafunctionofburnup.The2-dimensionalmodelwasdepletedattheoutletmoderatorALNIkP%lNIN21 CENPD487temperature,whilethe3-dimensionalmodelwasdepletedundermorerealisticaxialtemperaturedistributions.Itwasfoundthattheconservatismresultingfromthe2-dimensionaldepletionattheoutlettemperatureoutweighsbyfaranyotheraxialeffect.Thereforetheassemblyreactivitiesusedintheburnupequivalencingareconservativelyhigh,leadingtoconservativelyhighburnupvalues.4LlNIN/%INtN22 CENPD4875.0PostulatedAccidentsThereisavarietyofaccidentsthatcanbepostulatedtooccurinconnectionwithoperationsinthevicinity-ofthespentfuelpool.Fuelassemblydropaccidents,forexample,canusuallybeshowntonotresultinanysignificantincreaseinreactivityofthespentfuelpoolsy'tem.Thedesignofthestructuresinthespentfuelpoolandinterfacingsystemsaresuchthat,incombinationwithplantadministrativecontrols,theyprecludetheplacementofafuelassemblyintoareasnotdesignatedasintendedstoragelocations.AtSt.LucieUnit2,positionlimitswitchesonthespentfuelhandlingmachineprohibitplacementoffueloutsidetheregiondefinedbythestoragerackmodules.Thepresenceofthespentfuelhandlingmachineinterlockzonesisensuredpriortoeachfuelhandlingcampaign.Additionally,becausetherackmodulesarefreestandingwithoutattachmenttothefloororwallsofthespentfuelpool,nostructureexistsexternaltotherackmoduletosupport,intheverticalposition,anyfuelassemblywhichcouldbepostulatedtobeplacedthere.AfuelassemblydropaccidentresultinginanassemblylyingontopofthemoduleswillnotresultinanysignificantincreaseinsystemK,irbecauseofthelargeseparationdistancebetweentheactivevolumeofthefuelassemblieswithinspecifiedstoragelocationsandthefuelassemblylyingatopthemodules.Thelossofpoolcoolingaccidenthasthepotentialofraisingthetemperatureofthepoolcoolanttoaboilingcondition.TheconsequenceofthispostulatedaccidentonthesystemK,irwasconservativelyestimatedbyevaluatingthedXinanarrayofbothRegionIandRegionIIstoragecellscontaininga4.5w/oenrichedfreshassemblyburnedto50,000Mwd/t.ThemagnitudeofthechangeinKwaslessthan0.0040and0.0066forthezeroand350ppmsolubleboronconditions,respectively,foratemperaturechangebetween155to240degreesFahrenheit.Toassesstheconsequenceofpostulatedfuelassemblymisloadaccidents,avarietyofscenarioswereexamined.Thesescenariosallinvolvedthemisplacementofanunshimmedfresh4.5w/oenrichedfuelassemblywithoutaCEAinserted.Thisassemblywasplacedinthreepossibletypesofpositions:1)apositiondesignatedfora4.5w/ofreshfuelassemblycontainingaCEA,2)apositiondesignatedforthemorehighlyburnedfuel(1.3w/oequivalentenrichment)inRegionII,and3)selectedwatercelllocations.Thelatterchoiceservedtoquantifythebenefitoftheseisolationcellsbymaximizingthecouplingbetweensubarraysof1.82w/oand,or4.5w/ofuelassemblylocationsinRegionI.ThelargestdXobservedforpostulatedmisloadaccidentswas0.1016foratype3misloadposition.Casesexaminedforatype1misloadpositionresultedindXvaluesoflessthan50%ofthatforthetype3misloadwhereas,foratype2misloadposition,thebKwasapproximately75%ofthatforthetype3misloadposition.Thesolubleboronrequirementforatype3misloadwasdeducedtobe746ppmundertheassumptionthatafreshfuelassemblycouldbeloadedintoawatercell.Shouldphysicaldevicesorothermeansbeimplementedtoprecludethemisloadingofafresh4.5w/oenrichedfuelassembly,oritsequivalent,thisboronrequirementformisloadaccidentscouldbereducedbyroughly25%.Sincethemagnitudeofreactivityinsertionforthepostulatedfuelassemblymisloadaccidentsismuchgreaterthanthatresultingfromthelossofpoolcoolingevent,thelattereventdoesnotAlNfl/%OSIS23 CENPD487requireagreatersolubleboronlevelinthepoolthanthemostadversemisloadaccident.Thus,underthedoublecontingencycriterion,anincrementalsolubleboronallotmentof746ppmforaccidentsissufhcientforthefuelassemblymisloadandlossofpoolcoolingevents.ALNI24 CENPD4876.0SolubleBoronCreditSummarySpentfuelpoolsolubleboronisemployedinthiscriticalitysafetyanalysistooffsetthereactivityallowancesforcalculationaluncertaintiesinmodeling,storagerackfabricationtolerances,andfuelassemblydesigntolerances,aswellaspostulatedaccidents.ThetotalsolubleboronrequirementbasedonthecomponentsisdesignatedasSBCToTALintheequationgiveninSection4.3.Thecomponentsofthelatterquantityaresummarizedasfollows.SBC9se5SBCRp=350ppm=170ppmSBCPA=~746mSBCTpTAi.=1266ppmThisboronrequirementislessthanthesolubleboronconcentrationrequiredtobepresentintheSt.LucieUnit2spentfuelpoolbyTechnicalSpecification5.6.1.ALINESP%NIl25 0
CENP04&7Referencesl.2.3.45.6.7.8.9.101111213Newmyer,W.D.,"WestinghouseSpentFuelRackCriticalityAnalysisMethodology,"WCAP-14416-NP-A,Rev.01,November1996.LetterfromT.E.Collins,USNRCtoT.Greene,WOG,"AcceptanceforReferencingofLicensingTopicalReportWCAP-14416-P,WestinghouseSpentFuelRackMethodology(TACNO.M93254)",October25,1996.CodeofFederalRegulations,Title10,Part50,AppendixA,Criterion62,"PreventionofCriticalityinFuelStorageandHandling".U.S.NuclearRegulatoryCommission,StandardReviewPlan,Section9.1.2,NUREG-0800,July1981."St.LucieUnitNo.2UpdatedFinalSafetyAnalysisReport,"Amendment10,August7,1996,FloridaPowerandLightCompany."SCALE4.3-ModularCodeSystemforPerformingStandardizedComputerAnalysesforLicensingEvaluationforWorkstationsandPersonalComputers,"NUREG/CR-200;distributedbytheRadiationShieldingInformationCenter,OakRidgeNationalLaboratory,OakRidge,Tennessee."TheROCSandDITComputerCodesforNuclearDesign,"CENPD-266-P-A,April1983,CombustionEngineering,Inc.M.N.Baldwinetal.,"CriticalExperimentsSupportingCloseProximityWaterStorageofPowerReactorFuel;SummaryReport,"BAW-1484-7,July1979.S.R.BiermanandE.D.Clayton,"CriticalExperimentswithSubcriticalClustersof2.35wt%'UEnrichedUO2RodsinWaterataWater-to-FuelVolumeRatioof1.6,"NUREG/CR-1547,PNL-3314,July1980.S.R.BiermanandE.D.Clayton,"CriticalityExperimentswithSubcriticalClustersof2.35and4.31wt%U-EnrichedUO2RodsinWaterwithSteelReflectingWalls",NuclearTechnology,Vol.54,pg.131,August1981."InternationalHandbookofEvaluatedCriticalitySafetyBenchmarkExperiments,"NuclearEnergyAgencyandOrganizationforEconomicCooperationandDevelopment,NEA/NSC/DOC(95)03IV,LEV-COMP-THERM-001,2,3,4(Rev.0,3/31/95);LEU-COMP-THERM-010,017(Rev.0,8/31/96)W.Marshall,et.al.,"CriticalitySafetyCriteria",TANSVol.35,pg.278,1980.D.B.Owen,"FactorsforOne-SidedToleranceLimitsandforVariablesSamplingPlans",SCR-607,SandiaCorp.Monograph,March1963.lLIIIIPENIS26 CENP0487Table1SummaryofCalculationalResultsforCoresXThroughXXIoftheB&WCloseProximityExperimentsCoreRUNNo.X2348XI2355XI2359XI2360XI2361XI2362XI2363XI2364XII2370XIII2378XIIIa2423XIV2384XV2388XVI2396XVII2402XVIII2407XIX2411XX2414XXI24200.99610+0.000841.00049+0.000800.9988420.000771.00315+0.000810.99831+0.000801.00060+0.000780.99957+0.000781.00246+0.000800.99990+0.000820.99754+0.000890.99575+0.000870.9946520.000860.99158+0.000840.99230+0.000880.9947820.000790.99440+0.000830.99821+0.000810.99498+0.000820.9931820.00094Plate"TypenoneSS-304SS-304SS-304SS-304SS-304SS-304SS-304SS-304B/Al8/AlB/AlB/AlB/AlB/AlB/AlB/AlB/AlB/AlSpacing"'11111I121111.212123(a)-metalseparatingunitassemblies(b)-spacingbetweenunitassembliesinunitsoffuelrodpitchALllwlP%IN1I27 CENPD487Table2SummaryofCalculationalResultsforSelectedExperimentalPNLLattices,FuelShippingandStorageConfigurationsEXPT.No.COMMENTS0430.99787+0.001060441.00104+0.001020450.99955+0.001010460.99960+0.001030610.99792+0.000990620.99628+0.000960640.99696+0.001030710.99970+0.001010790.99463+0.001020870.99423+0.000990930.99787+0.00098Uniformrectangulararray,nopoisonCC<c2x2arrayofclusters,nopoison2x2arrayofclusters,0.302cmSS-304cross2x2arrayofclusters,0.485cmSS-304cross2x2arrayofclusters,crossof0.3666gboron/cm2x2arrayofclusters,crossof0.1639gboron/cm2x2arrayofclusters,crossof0.1425gboron/cmNNIkERNIE28 CENP0487Table3FuelParametersEmployedinCriticalityAnalysisforSt.LucieUnit2SpentFuelStorageRackNumberofFuelRodsperAssemblyUOzPelletOD(in)Zr-4CladTubeOD(in)CladTubeWall(in)NominalUO2StackDensity(g/cc)FuelRodPitch(in)'EAGuideTubeOD(in)CEAGuideTubeID(in)NumberofGuideTubesperFuelAssembly2360.32550.3820.02510.310.50650.9800.9004~8LI%INPINES29 CENPD487Table4St.Lucie2Unit2SpentFuelRackK,<withNoSolubleBoronK-eFectiveNominalReferenceValue0.97001alculationalandMethodoloBiasesMethodologyPoolTemperature(50'Fto155'F)Total0.002590.003750.00634TolerancesandUncertaintiesUO2Enrichment(0.05w/o)UO2StackDensity(2%)CellWallThickness(0.005in)CellID2PitchAsymmetricFAPosition95/95CEAWorth95/95MethodologyUncertainty95/95CalculationalUncertainties0.013800.003810.002930.013420.000000.005450.006390.00220TotalUncertainties(statistical)TOTAL0.021660.99801lLII30 CENp0487Table5St.LucieUnit2SpentFuelRackK,<withSolubleBoronCreditK-efFectiveNominalReferenceValue350PPMSolubleBoronCalculationalandMethodoloBiase0.91497MethodologyPoolTemperature(50'Fto155'F)TotalTolerancesandUncertainties0.002590,005600.00819UOzEnrichment(0.05w/o)UO2StackDensity(2%)CellWallThickness(0.005in)CellIDEcPitchAsymmetricFAPosition95/95CEAWorth95/95MethodologyUncertainty95/95CalculationalUncertainties0.015300.004740.002250.016750.000000.005270.006390.00220TotalUncertainties(Statistical)0.02481Total0.9479731
CENPD487Table6-1St.LucieUnit2SpentFuelRackTabulationofBurnupvsInitialEnrichmentandDecayTimeYearsRegionII,1.3wloEnrich4.54.44.34.24.14.03.93.83.73.63.53.43.33.23.13.02.92.82.72.62.52.42.32.22.12.01.91.81.71.61.5r0466974594344940437854254941280400113875837527363193512633939327473153930309290492775526429250T3236922229420884194691805116628151871370812153104678574637014586545060440574293141739405173929238075368723568134497333133212130912296812842327138258252448T2313021760203811899817613162211481113361118391019483586241245071442194321642118486639790386063742336246350723389832717315253031529084278292655125250239302259621252199031855217198158361445613037115489944816561293443144341942415413434023139096379523680235650344923332732150309582974728516272642599324704234012208820769.1S4491812716804154731412312734112789715799Q603344359242657416544060639531384363732938211350823394032T8431611304192920827977267282546324185228972160520311190171772516431151301380912450110269503l8315949399063886537809345413341532267310983924138232372123617335113340273291531776306102869527465262182495923692224192114619875186071734316077148051351212182107919306768558762820826978257342448123223219652071019461182181698015742144971323211931105719123755158115642906~42253419324124440242.741633405903958938609376323664535638346043353932441313093014728958277452651625274240272277821534202971906817849166361542414205129671169310363895274275753841045399703896S380093706236107351303412233076319903086629707285192730626077248382359522356211241990418695174981630915122139291271611468101678790731157009404873938138381374403652135597346493366432636315633044629290281022688925660244232318621955207361953118341171651599914S36136661247811255998186377202565110399583882437824369013600835'1133419233230322193115730047288942770626493252642402922797215742036719177180051684915705145641341712251110539805849270985605'11394583829537296363893552234655337593281931824307732966928519273312611824889236562242S21213200161884117686165501542614307131811203610860963783546998556112389S4377943679535905350623422133350324293145030409293112816326975257612453223301220782087019684185221738316265151611406212956118321067694768221690355181338536373203632135446346263381032962320613109630064289712782526638254232419421745205441936818219170961599614910138291274311638105019323809468125477143811136871358723501234213334203259431711307602973828649275052631825102238732143020236190691793216824157391467113609.1254011452917779736l245437153771036446354473460033822330523224631381304422942828344272022601424T98235692113019942187851766016565154961444513399123471127610176903778576639539816373293604335044342103345232T023191731067301412913528055269142572724510232S12205520846196641851517401163201526614230132001216411109100258904774665585360173696935662346623384133101323T13160430770298552885727781266412545424236230072178320577194011826017156160871504714025130111199Q10950988287787641648253241836626352993430033490327673205T313073048829584285932752126383251952397722748215252032219151180171692315866148391383212832118251080097478660754464115292193630034956339563315832451317583102530219293262834127274261372495023731225022128020080189141778716703156561464213648126621166910659962085507453634752632035988346293363032842321513147430756299642908028102270392590424717234982226921049198511869017570164931545714454134731250011522105269503844973726290524032 CENPD487Table6-2St.LucieUnit2SpentFuelRackTabulationofBurnupvstnitialEnrichmentandDecayTimeRegionll1.5wloYearsEnrich014.539660390594.438263376944.337043364864,235940353854.134908343494.033909333453.932915323473.831903313363.730859302993.629777292283.528651281203.427482269733.32627625T923.225038245S13.123776233473.022499220962.9'1214208352.819928195S92.718644183042.617366170392.516088157732.414804145002.31350013210'2.212154118852.110740105032.0,92199034423438484379353741037149366283613135954354453495934854343473386233815333043281632806322913179931805312873079330795302792978629764292542876728705282062773027613271302666926487260252558425331248912447224146237312333722938225492217921712213482100220475201331980919230189081860317981176761738816731164391616415477151971493414215139471369512938126S4124451163411399111801028410081989188658710856853691035657344953340032351313303032329317283042727726231251642407422961218272067319501183141711415904146851345712221109T597158436678936433359803555035141352053477534367339793405433634332353285632961325423214431766319093148831087307073088430460300562967329874294482904328658288702844528041276582786227443270442666526845264352604525675258142541T250402468224764243852402423681236952333522993226682260522265219432163721493211752087320587203602006419782195141920918931186681841818040177791753217298168551661016376161551565815424152031499314449142271401613S1613233130211282012630120101181011622114431078210600'0428102659550939492489109831481998091798910113475334386336113326332496321553140831069303473000529310289652829327947272942694926306259652532424991243422402023356230472235922066213472107120315200561926019018181801795517075168631594515746147941460513626134461245012278112731111210111.99648977885278927800123403S32933318333074729681286392761926622256422467423714227542178820809198111878917740,1666315556144251327512115109599824873377121333709326203152730442293742832927309263122533524375234242247721524205611957818572175371647215376142541311211960108139691861976271415333973310132324320443123730963301532988029084288092803627759270142673526018257392504524770240912382223150228892221321964212752103820325201021935719148183651816917344171601629016118152051504314092139381295712810118121167210674105429564944385108406754674681617'183282232556323043177831526312873070430457302232962129375291422854828300.2806527495272462700926471262202598125476252252498724509242622402723567233252309522642224082218621727215032129020813206002039819890196891949918949187611858317984178071764116987168221666615955158001565414889147431460413T9113652135201267012537124111153911412112921041610297101849328921991168307821481267394732472591920320643183531059308413000029787289192870727841276272678326567257552553824761245462380323591228772266921975217742108820896202062002419318191471841418253174831733316518163781551515384144731434913396132791229312181111791107310078997890198930804479687200714633 CENPD487Table6-3St.LucieUnit2SpentFuelRackTabulationofBurnupvsInitialEnrichmentandDecayTimeRegionI,'1.4wloEnrich4.5444.34.24.14.03.93.83.73.63.53.43.33.23.13.02.92.82.72.62.52.42.32.22.12.01.91.81.71.61.5Years043355423364126840163390293787536705355233433333134319283071429492282612701825762244922320421897205691921717839164321499413522120131046288667219551437461426374166340614395123837237208360303484333652324583126430067288672766026445252182397722718214402014018815174631608214670132241174210220865370365360361724195141022399923889137745365723538534192330013181430631294502827127088258992470023487222572100619733184331710715751143651294611491999884616873522535053412984041239399383003714835965347693357232381311993002728863277Q32654425380242082302221819205951934618072167701543914078126841125797938285672751073409440675398303883537738365793538734183329813179030614294522830327163260262488723740225812140320204189801772916451151441380712439110399603812565955002332554X$23927838298372023603734836336253241831227300562S905277712664925534244182329622161210081983218632174041614914865135521220910835942779776476490832526395193875237788366943552234313330943188330692295262S3842726426161250662397322874217621948018302170961586314601133101199210644926278406366482431877389833825337303362103503333815325893137430183290222789026783256962462123549224722138320276191461798916804155911435013082117871046391087712626547473129891038474379923753437778373283690136842364053599135751353153490234568341273370933343328953247032110316553122430891304322999729700292412880728543280892765827420269742655126326258922548125256248372443924199237982341723147227652240322091217302138621024206822035819938196161931118828185271824117692174101714216527162641601515334150901485914114138891367612866126621246811593114101123510293101329979896288248693759274797371617060S159964675460845443076302729811137100364963559834509333123206730815295852839427249261502509024062230562205821060200501902217969168881577814639134741228311070983385687268591444832937123668836112352253413832937316853042829195280042686225769247202370522713217322075019758187471771116647155531443113281121081091296948449716858364424289413362993574834871337863258131323300612882527634264952540924369233662142219480184861746616418153401423313099119411076295618334707357604367285314359303540334537334523224430981297142847527283261472506724036230442207921128201771921718238172341620115137140451292511783,10619943482256982568743112813153558135077342203313631924306562938528143269512581824743237212273921787199131896818003170141599414945138661276111632104839313812168945616425727741635250347673391932837316223034929073278282663625506244372342222450215092Q58519662187311778116804157991476213696'26041148910353919980216811554942062736173%36344753363532554313353005828777275302633825210241462313822177212472033419425185071756916606156131458913535124551135310231909079276733548741582701183463834197333663228531063297S12849627247260542492923869228702191720998200971920018294173691641815437144241338212314112241011589887840666054294114266819343553393533111320303080529518282292697725784246612360722614216712076219&73189871809317180162401527014268132371218011102100068893775965945378407626392034086336863287031789305602926827974267202552724407233582237221438205391966118786179Q3170011607215112141201310012054109879904880576866537533540462616 CENPD487Table6QSt.LucieUnit2SpentFuelRack.TabulationofBurnupvsinitialEnrichmentandDecayTimeRegionI,1.82w/oYearsEnrich04.5304444.4293934.3283774.2273814.1263934.0254043.9244073.8234003.7223793.6213433.5202S43.4192313.3181583.2170763.1159873.0148932.9137942.8126912.7115812.6104602.593242.481642.369702.257282.144202.030251230005295872896828562279662757326984266052601025644250352468324052237142305922733220512173921029207301999319707189441867217885176271681716574157431551414665144511358213384124951231411402112381030010153918290548041793068656773564155664350429229722928342918928809281762780727199268422624325&98252952496224346240262339023082224232212721441211582044620175194361917818414181701738317152163441612715299150961425114063132001302812146119901108710947100199896893788307831774166916617550054424241419828922862528446274562650225569246452372022788218452088819917189331793816933'59211490513887128661184410817978287337660655153914161283667828099277682745227120268002649526178258682557425256249582467424343240552378223429231522288922509222422198921577213212107820631203872015519672194391921718700184791826817717175081730916725165281634115727155431536814725145541439213720135631341412715125721243711707115791145710696105821047596769577948586428558848075857515745164916436638453455303526441284098407028142795277792715026204252S3244032352122638217482084719934190071806817119161631520214238132731230911343103749397840673906336522740442759102686325927250272414623274224002151920628197241880617878169401599415044140921313912187112341027893148335733262905192401827421112265892633025664254142477324533239022367023039228152217421959213022109520419202211952419334186161843517697175251676916606158331568014894147511395313821130121289012071119611113011031101861009992359159826882047277722362466203515851253994396927252707132608525178243052345022603217552089920033191541826317362164511553514615136941277411855109371001690878143717261625093394426M1415258552564024955,247452408923886232422RNS224032221221562213782071320537198541968518983188211810017945172071705916304161651539715265144861436313574134601266412558117551165910846107609936985990178951808380267123707661226083506150313919389526692648161718254422526025097245502436924202236942351523348228592268422518220322186121700212042103920882203692021020059195241937219227186671852118383177981765917527169191678716662160331590715788151401502214910142461413514030133511324813151124581236312273115681148111399106781060010526978697179652888788278771797279217873703069886948604660125980500149734S473871384838272628260725M19202495324830240M239152319323050223642221821547214032073420593199161978019089189581825118127174021728416543164311567715571148051470613932138391305912974121891211111322112511045710394959195368718867178307791691368825951592749254906380837922570255435 CENPD4870Table7SummaryofGadoliniumFuelAssemblyTypesValueAddedFuelDesignNo.GadPinsGadLoadingEnrichEnrich('v/oGd203)NonGadpinsGadPins5.0DensityGadPins(g/cc)AssemblyAverageEnrich5.0012165.05.05.05.05.04.54.04.010.189510.189510.1895,10.123810.12384.974.974.93ALINIkP%INIS36 I20)l)9<NO)t1NOOV)t)A)VSTVi)NSTAILTOW)TN9)ICINVVSIIISOHIINTtl)ASSH(h'INl~llVVN~4a5)NCVISelICiu50$STOAACt~)4TOTALCILLS1)lVSA4LtCtLLSA(C<(Wll095~965LNCNI5If))thi)5>STOIIACIll)CTOTALCILL)45)VSA4)tCttl'IElh0>OmC2r+m>C2mthImr~rOr.0g2TIIO+OrDr~mTTTIt)AzrC~A~43D180nIIIIIIIIIIUI21)5521216I'LC'521I))ALCS12 CENPD487Figure2TypicalSpentFuelStorageRacklLtioduteLINSERTL.INSERTLOCKINGHOLEoorrFUELASSEMBLYSUPPORTPLATESLOTFLOWPASSAGES38FLORIOAPOY/ERII.LIGHTCOMPANYST.LUCIEPLAIITUNIT2TYPICALSPENTFUELSTORAGERACKMOOULEFIGURE9.l2 CENPD487Figure3TypicalSpentFuelRackModuleL-InsertFlORIDAPOITER8LIGHTCOMPANYST.LUCIEPLANTUNIT2TYPICALSPEiVTFUELRACKh>>ODVLELINSERTFIGURE9,I3;)
CEl4PD487Figure4L-Inserts8.7401888.74oSECTIONA-AIIII4DETAILZ46'WEI.DEDCELLBLOCKINGDEVICE"L"INSERTIVIODIFIED"L"INSERTFLORIDAPOWER8,LIGHTCOIIPANYST.LUCIEPLANTUNIT2LINSERTS40FIGURE9.13b H~)I7al0fLKLSTO11Qf.INXWLEAllfUELSTOIIAQEINXNUi%VIEWDETAILZ73+DETAILYF10fLKLSTOIIhQSMODULE4sllfUfLSTQIIAQf.ICXNLKl/lDngcr-OC>IC)C)i~~PmC)m178Yi'./iVIEW8-8DETAILWDETAILVDETAILLIBOTTOMVIEWELEVATIONNOTE:ALLOIMENSIONSAREININCIIES CENP0487Figure6FuelAssemblyALIGNMENTPOST6.371SPACERGRIDIjUPPERENDFITTINGCEA~~~)~'4II4~%4I.'0040404044400000GUIDETUBEASSEMBl.YTOPVIEWFUELROD158,1"OVERALL04040444004444136.rACTIVEFUELLENGTHREGIONGANDBEYOND136.7ACTIVEFUELLENGTHREGIONA-F300oooo0088IIo80088888888888880088HALI040~444~44044~0~BOTTOMVIEW3.413REIL43.112AEG.Q4.732REQ.Q4.703BEG.FLOWERENDFITTINGAMENDMENTNO.8(9/93)FLORIDAPOWER8(LIGHTCOMPANYST.LUCIEPLANT-UNIT242FUELASSEMBLYFIGURC4.2-6 CENPDQ87Figure7SpentFuelRackModuleForRegionIFUELASSEMBLYCELLBLOCKINGDEVICE"L"INSERT43FLORIDAPOWER8"LIGHTCOMPANYST.LUCIEPLAHTUHIT2SPENTFUELRACKMOOULEFORREGIONIFIGURE9.1.5a
CENPD487Figure8SpentFuelRackModuleForRegionIIFUELASSEMBLYCELLBLOCKINGOEVICEFLORIDAPOWER8'IGHTCOMPANYST.LUCIEPLANTUNIT2SPENTFUELRACKMODULEFORREGIONIIFIGURE9.1-5b CENPD487Figure9SpentFuelLoadingPatternForRegionIColorCodedPatternpp,N~a~0Class3or5Class4or6Class7or8Class9"EmPty(0)Class3or5IBlackandWhitePatternUsingClassNumbers3/53/53/54/63/50003/54/63/54/6003/S07/84/607/83/507/84/607/87/83/54/6003/54/6007/87/87/87/80007/83/54/6003/S4/6007/87/87/87/8007/87/83/54f63/54/600003/S4/63/54/600007/87/8'/87/87/8.7/87/87/800007/87/87/87/83/57/87/80003/S7/87/80007/87/87/87/87/87/80007/87/87/83/54/63/54f60004/63/54/60007/87/87/87/87/87/80007/87/87/83/54f63/54/60004/63/54/60007/87/87/87/87/87/80007/87/87/83/54/63/50003/S4/63/50007/87/87/87/807/807/87/807/87/84/63/5004/63/504/603/504f603/504/64f63/504/603/504/603/504/603/504f63/53/53/53/507/84/607/83/S07/84/607/83/S07/84/607/87/87/87/87/807/807/807/807/807/807/803/5003/50003/500003/503/500007/87/87/87/87/89997/89997/899903/500007/87/87/89999999993/57/8903/500007/87/87/89999999993/57/87/807/87/8007/803/57/8007/803/S7/8007/807/87/807/87/807/87/807/87/807/87/807/87/803/504/603/504/603/504/603/504/603/504/603/S04/6IAI%INr+IrrrClass0)3)4)5)6)7)8)9)LimitsEmptyRegion1Region1Region1Region1Region1Region1Region1Key4.5w/oU-235equivalent4.5w/oU-235equivalentwithCEAinserted5.0w/oV-235equivalentwithGd.poisonrods5.0w/oU-235equivalentwithGtLpoisonrodsandCEAinserted2.82w/oU-235equivalentwithCEAinserted,1.82w/oU-235cquivalcnt1.4w/oU.235equivalent
'I'l~~'I CENPD487Figure10SpentFuelLoadingPatternForRegionIIY.aS8aYj..MMmiMMBlIMS5NHSL'mlS8.Y,YQgimglmggggjlnggBQQQQ~QQQQggggQigKNClass1Class2Empty(0)Class0)l)2)KeyLimitsEmptyRegion2:l.3w/oU-235equivalentRegion2:l.Sw/oU-235equivalentfLENIDP%ISIN46 CENp0487Figure1150000RequiredFuelAssemblyBurnupvsInitialEnrichmentandDecayTimeRegionll,1.3w/o0years-40000DI-g30000K~20000~1OOOOAcceptableBumup5years10years15years20years'.52.02.53.03.54.04.55.0InitialU-235Enrichment(w/0)1LAllP%RNIS I-CENPD487Figure1240000RequiredFuelAssemblyBurnupvsInitialEnrichmentandDecayTimeRegionII,1.5w/o0years5yearsD30000CL2000010000ILAcceptableBurnup10years15years20years1.52.02.53.03.5InitialU-235Enrichment(w/0)4.04.55.0 CENPD487Figure13RequiredFuelAssemblyBurnupvsInitialEnrichmentandDecayTimeRegionI,1.4w/o40000I-Q>30000EGl~2000010000AcceptableBulTlup0yearsyears10years15years20years1.52.02.53.03.5initiaiU-235Enrichment(w/o)4.04.55.0iLINII.PRIS%
CENPD487Figure14RequiredFuelAssemblyBurnupvsInitialEnrichmentandDecayTimeRegionI,1.82wlo0yearsI-c25000AcceptableBumup5years10years20yearsLQIC)EgClEILL2000015000100001.52.02.53.03.5InitialU-235Enrichment(w/0)4.04.55.0ALMINPL&IN50 CENPD487Figure1515000RequiredFuelAssemblyBurnupvsInitialEnrichmentRegionI,2.82w/00yearsDI-10000C5oooE"3+4504.5'E'2-6086AcceptabteBurnup>-484.92E-7783.11.52.02.53.03.5InitialU-235Enrichment(wlo}4,04.55.0iLMINPRISING5I CENPD487tCFigure161.31.25K-infinityat5.0wlowith90%GadWorthhrough60000NlWD/T)1.21.15C1.05~0Gad4.5w/o~4Gad-4~8Gad.4~12Gad-4~8Gad.6~16Gad-6~0Gad5.0wlo0.950.90.850.80100002000030000AssemblyBun1up(MWD/MTU)400005QOQQ6OOQQ4SINP'LlÃll52
CENPD487Figure17K-infinityat5.0w/owith90%GadWolthThriiIh':20000;IN@fDlT.':-.";.'-:-':0Gad4.5wlo~4Gad.4~BGad4~12Gad.4~BGad.6~16Gad6~0Gad5.0wla20004000eaaoeaoo1oaaa1200014ooo1eooo1eooo2ooooAssemblyBurnup(MWD/MTU)53 C'
St.LucieUnit2DocketNo.50-389ProposedLicenseAmendment'yai~Md't.LucieUnit2SpentFuelPoolDilutionAnalysis,PSL-ENG-SENS-97-068,Revision0:FPLNuclearEngineering,November,1997.