ML17216A616

Rev 1 to St Lucie Unit 1:New & Spent Fuel Storage Criticality Safety Evaluation for Natural U Axial Blanket Fuel.

ML17216A616
Person / Time
Site:	Saint Lucie
Issue date:	02/28/1986
From:	BROWN O C, MALODY C W, PATTEN T W SIEMENS POWER CORP. (FORMERLY SIEMENS NUCLEAR POWER
To:
Shared Package
ML17216A614	List: ML17216A613 ML17216A615 ML17216A616
References
XN-NF-83-36, XN-NF-83-36-R01, XN-NF-83-36-R1, NUDOCS 8607150141
Download: ML17216A616 (29)

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XN-NF-83-36,Rev.1IssueDate:2/28/86ST.LUCIEUNIT1NEWANDSPENTFUELSTORAGECRITICALITYSAFETYEVALUATIONFORNATURALURANIINAXIALBLANKETFUELPreparedby0.C.BrownFebruaryl986EONNUCLEARCOMPANY,INC.8b071501418b0708PDRADOCK05000355'"PDR XN-NF-83-36,Rev.1ST.LUCIEUNIT1NEWANDSPENTFUELSTORAGECRITICALITYSAFETYEVALUATIONFORNATURALURANIUMAXIALBLANKETFUELPreparedby:rown,ngsneerBWRNeutronicsaeApprovedby:'oy,arCorporateLicensingzanfaen,anagerNeutronicsandFuelManagementjrs 0I XN-NF-83-36,Rev.1ST.LUCIEUNIT1NEWANDSPENTFUELSTORAGECRITICALITYSAFETYEVALUATIONFORNATURALURANIUMAXIALBLANKETFUELTABLEOFCONTENTSSectionPage1.02.03.03.13.23.33.44.04.14.24.34.45.06.07.

08.0INTRODUCTION

..............................................SUMMARYOFRESULTS........................................SPENTFUELSTORAGEPOOLANALYSIS..........................Design-BaseFuelAssemblyDescription......................StorageArrayDescription.................................StorageArrayReactivity..................................Concluslons~~~~~~~~~~~~~~e~~~~~si~o~oo~~~~~~~o~~~~~~~~~~~~NEWFUELSTORAGEROOMANALYSIS............................DesignBaseFuelAssemblyDescription.....................StorageArrayDescription.................................StorageArrayReactivity..................................COnC1us1OllS~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~o~FUELINSPECTIONELEVATOR,UPENDER,ANDTRANSFERTUBE......CALCULATIONALMETHODS.....................................COMPUTERMODELREVIEWANDVALIDATION..............;.......REFERENCES.................................................APPENDIX1-SECOND-PARTYREVIEWDOCUMENTATION123333566667891011 XN-NF-83-36,Rev.1ST.LUCIEUNIT1NEWANDSPENTFUELSTORAGECRITICALITYSAFETYEVALUATIONFORNATURALURANIUMAXIALBLANKETFUELLISTOFTABLESTablePageSt.LucieUnit1NominalFuelAssemblyParameters.........12SpentFuelStoragePoolReactivitySensitivityCalculationResults...........'........................;...............13NewFuelStorageRoomReactivityCalculationResults......14

)~l XN-NF-83-36,Rev.1ST.LUCIEUNIT1NEWANDSPENTFUELSTORAGECRITICALITYSAFETYEVALUATIONFORNATURALURANIUMAXIALBLANKETFUEL

1.0INTRODUCTION

ThisreportsummarizestheresultsofthreecriticalitysafetyanalysesperformedforthehandlingandstorageofnewandspentfuelattheSt.LucieUnit1NuclearGeneratingStation.Specifically,theanalysesaddressedthefollowingareas:1)SpentFuelPool(Section3.0)2)NewFuelStorageRacks(Section4.0)3)FuelInspectionElevation,Upender,andFuelTransferTube(Section5.0)AnExxonNuclearCompany(ENC)fuelassemblydesignwhichincludesnaturaluraniumaxialblanketsontheassemblyendsandacentralfuelregionenrichedtoamaximumof4.0wtXU-235wasassumedfortheanalyses.DetaileddescriptionsofthehandlingandstorageareasisprovidedinthecriticalitysafetyevaluationreportsumnarizedinReference1.\

XN-NF-83-36,Rev.12.0SUMMARYOFRESULTSCalculationsperformedforthehandlingandstorageof4.0wtXU-235enrichedfuelassembliesexternaltotheSt.LucieUnit1reactorcoreindicatethattheapplicablecriticalitysafetycriteriaaremet.Worstcasereactivitiescalculatedforeachareaareasfollows:AreaCalculatedkeff(95KCL)Limitingkeff(9NCL)CriteriaReferenceSpentFuelPoolNewFuelStorageRoomFuelElevator,Upender,TransferTube0.9180.9250.9240.950.980.95 3tXN-NF-83-36,Rev.I3.0SPENTFUELSTORAGEPOOLANALYSISThehighcapacity(HI-CAPŽ)spentfuelstorageracksweredesignedtoaccomnodate728fuelassembliesandaregenerallydefinedinAttachmentAofReferenceI.3.1DesinBaseFuelAssemblyDescritionTheSt.LucieUnit1spentfuelstorageracksarecurrentlydesignedandlicensedtoacceptfuelassembliesenrichedto3.7wtXU-235.TableIsummarizesfuelassemblyparametersforthisfueldesign,aswellasparame-tersfortheExxonNuclearfueldesign.AlsolistedinTableIarefuelassemblykcalculationresultsobtainedusingtheCCELL(4)computercode.(CCELLisapincellcalculationcodeusedtocell-averageresonancecorrectedcrosssectiondataforinputintoothercodes,i.e.,KENO,etc.)Theseresultsindicatea+0.015bkchangeinfuelassemblyreactivitybetweenthetwofueltypes.3.2StoraeArrayDescrition(SentFuelPoolAnalysis)ThespentfuelstoragearraydesignanddimensionsaredescribedindetailinReference1.Thearrayconsistsofsquarestainlesssteelcanshavinganinsidedimensionof8.4835inches.Thecanshaveanominalwallthicknessof0.25inchesand-arefixedinasquare-pitchedarrayonnominal12.53-inchcenters.3.3StorageArrayReactivity(k)(SpentFuelPoolAnalysis)ForthenominalstoragearraygeometrydefinedinSection3.2,keffwascalculatedfortheExxonNuclearfuelenrichedto4.0wtX,U-235usingtheKENOIV(5)MonteCarlocomputercode.(CrosssectiondatafromtheXSDRN123-energygrouplibrarywerepreparedforinputintoKENOIVusingthe ll XN-NF-83-36,Rev.I,NITAWL(6)andXSDRNPM(6)codes.AdetaileddescriptionofthecalculationmethodisgiveninSection6.0.)Forapoolwatertemperatureof68oF,akeffof0.874+0.005wascalculatedassuminganeffectivelyinfinitearray.FromresultssummarizedinReferenceI,a8<of+0.034hasbeenestablishedbetweenthenominalandworstcase(minimumoffset)storagearrayconditions.ApplyingthishktotheKENO-calculatednominalkeffvalueresultsinaworstcasekffof0.918(*)atthe955confidencelevel.Forpostulatedaccidentssuchasthedroppingofafuelassemblyontopoftheracksorhavinganassemblybyaccidentachieveanyotherabnormallocationinthepool,creditmaybetakenforrealisticinitialpoolcondi-tions(2).Theseconditionsincludetakingcreditforsolubleboron(>1720ppm)presentinthepoolwater.Atabout1700ppm,boronstoragearrayreactivity(keff)isreducedaPProximately20%hk.Hence,Postulatedaccidentsdefinedaboveareoflittleconcernfromacriticalitysafetystandpoint.Tobetterunderstandthereactivitysensitivityofthestoragearrangementtostainlesssteelcanwallthicknessandfuelcellcenter-to-centerspacing,severalcalculationswereperformedusingtheone-dimensionaltransportcodeXSDRNPM.Acylindricized-equivalentnominalstoragecellwasmodeledwithareflectivecellboundarytoapproximateaninfinitearray.ResultsofthesecalculationsaresummarizedinTableII.Forastainlesssteelcanwal1thicknessdecreaseof0.05inches,storagearrayreactivityincreasesabout+0.005hk.Forastoragecellcenter-to-centerspacingdecreasefrom12.4375inchesto12.0000inches,resultsindicateareactivityincreaseofabout+0.020&.*keff(MC)=0.874+(2)(0.005)+0.034=0.918(95Kconfidencelevel).

XN-NF-83-36,Rev.13.4Conclusions(SentFuelPoolAnalsis)TheresultsofthisanalysisdemonstratethatExxonNucleardesignfueldefinedinTableIandenrichedto4.0wtXU-235canbestoredintheSt.LucieVnit1storagepoolandcontinuetomeetNRCcriticalitysafetycriteria,i.e.,theneutronmultiplicationfactorinthepoolshallbe(0.95underworstcredibleconditions.TheadequacyofthecalculationalmethodsusedinthisanalysisisdiscussedinSection7.0.

XN-NF-83-36,Rev.14.0NEWFUELSTORAGEROOMANALYSISThenewfuelstoragearraywasanalyzedin1979(1)forCEfuelassembliesenrichedto3.70wtXU-235.Resultsofthisanalysisindicatedthemaximumstoragearrayreactivity(keff)tobeaboutG.92foralldegreesofuniformlyinterspersedmoderation.4.1DesinBaseFuelAssemblyDescriptionTheExxonNuclearfuelassemblydefinedinSection3.1andTableIwasusedinreactivitycalculationsforthenewfuelstoragearray.4.2StoraeArrayDescrition(NewFuelStoraeRoom)TheSt.LucieUnit1newfuelstorageroomconsistsofa10x10fuelassemblyarrayarrangementwiththetwomiddlerows{runningnorthandsouth)removed.Theroomhasconcretewallsaroundtheentirearrayandcellsarespacedon21-inchcenters.Thefuelisnormallystoredinthedrycondition.AdditionaldetailsconcerningthearrangementcanbefoundinAttachmentBofReference1.4.3StorageArrayReactivity(k)(NewFuelStorae)Sincethenewfuelisstoreddry,reactivitycalculationswereperformedforvaryingdegreesofmoderationintheeventthearraybecamemoderated.Forthecaseoffullflooding,thearraywouldremainsubcriticalduetoneutronisolationbetweenfuelassemblies.Forthecaseofuniformmoderationinterspersedwithinandbetweenfuelassembliesinthestoragearray,i.e.,aqueousfoam,etc.,123energygroupKENO-IVcalculationswereperformedforwaterdensitiesinthearrayrangingfrom15%water(byvolume)to2.5X.ResultsofthesecalculationsaresummarizedinTableIIIandindicatethemaximumkeffofthearraytobe0.925atthe95Kconfidencelevel.

7XN-NF-83-36,Rev.14.4Conclusions(NewFuelStorae)TheresultssummarizedinSection4.3andTableIII'emonstratethatthemaximumkeffortheSt.LucieUnit1newfuelstorageroomwillnotexceedthelimitingcriterionof0.98foralldegreesofuniformmoderationinthearray.Specifically,themaximumreactivityoccursforamoderatorvoidfractionbetween0.90and0.95andisestimatedtobeabout0.925atthe95Kconfidencelevel.

XN-NF-83-36,Rev.15.0FUELINSPECTIONELEVATOR,UPENDERANDTRANSFERTUBEForthefuelinspectionelevator,upenderandtransfertube,keffcalcula-tionswereperformedforthreeworstcasesituationsinthepreviousevalua-tion,seeAttachmentCofReference1.Thecasewhichproducedthehighestreactivityinvolvedthefuelinspectionelevator.Forthiscase,itwasassumedthatonefuelassemblywasintheelevatorandoneadditionalassemblywaslocatedfour(4)inchesedge-to-edgefromtheelevatorassembly.Assumingthiscondition,aKENOcalculationwasperformedfortheExxonNuclearfuelassemblydefinedinTableI.Thiscasewasrunwith18energygroupcrosssectiondatapreparedusingCCELLandgavearesultingkeffof0.914+0.005or0.924atthe95K,confidencelevel.Hence,itisconcludedthat'thefuelinspectionelevator,upenderandtransfertubewillallmeetthekeff<0g5criterionforthe4.0wtXU-235enrichedfue'l.

0II' e9XN-NF-83-36,Rev.I6.0CALCULATIONALMETHODSTheKENO-IVMonteCarlocode(5)wasusedtocalculatethereactivitiesofthestoragearraysandfuelelevator.MultigroupcrosssectiondatafromtheXSDRN123grouplibraryweregeneratedforinputintoKENO-IVusingtheNITAWL(6)andXSDRNPM(6)codes.Specifically,theNITAWLcodewasutilizedtoobtaincrosssectiondataadjustedtoaccountforresonanceself-shieldingbytheNordheimIntegralMethod.TheXSDRNPMcode,adiscreteordinatesone-dimensionaltransporttheorycode,wasthenusedtopreparespatiallycell-weightedcrosssectiondatarepresentativeofthefuelassemblyforinputintoKENO-IV.Crosssectiondataforthefuelelevatorkeffcalcula-tionwerepreparedusingtheCCELLcode.CCELLisacombinationoftheHRG(8)andTHERMOS(9)codes,andproducesmultigroupcrosssectiondatatreatedinasimilarfashiontotheNITAWL/XSDRNPMmethodology.

10XN-NF-83-36,Rev.17.0COMPUTERMODELREVIEWANDVALIDATIONThecalculatedworstcasekeff(0.918)forthespentfuelstoragearrayisaboutAlessthanthecomparablevaluefor3.7wtXfuel(0.947)reportedinReference1.ThisisapparentlyduetoahighdegreeofconservatismintheReference1calculationalmodel.Thecomputercodemodelsusedforthecalculationsinthisreporthavebeenbenchmarkedagainstexperimentaldataandadequatelyreproducethecriticalvalues.(Ontheaverage,thecriticalvalueisreproducedtowithinonestandarddeviation.)DetailedresultsofthesebenchmarkcalculationsaregiveninReference7.Inaddition,theresultsandconclusionsofthiscriticalitysafetyevaluationhavebeensecond-partyreviewedbyanindividualknowledgeableintheareaofcritical-itysafety.ThefindingsofthisreviewaregiveninAppendixI.

g'I XN-NF-83-36,Rev.

18.0REFERENCES

2.Letter(withattachments)fromR.E.Uhrig(FPL)toV;Stello(USNRC),"St.LucieUnit1DocketNo.50-335ProposedAmendmenttoFacilitiesOperatingLicenseDPR-67,"datedOctober4,1979.LettertoallPowerReactorOperatorsfromB.K.Grimes(NRC),"OTPositionforReviewandAcceptanceofSpentFuelStorageandHandlingApplications,"datedApril14,1978.3.AmericanNuclearSocietyStandard,ANS-N18.2.4.W.W.Porath,"CCELLUsersGuide,"BNW/JN-86,PacificNorthwestLabora-tories,February1972.5.L.M.PetrieandN.F.Cross,"KENOIV:AnImprovedMonteCarloCriticalityProgram,"ORNL-4938,OakRidgeNationalLaboratory,November1975.6.N.M.Green,et.al.,"AMPX-AModularCodeSystemforGeneratingCoupledMultigr'oupNeutron-GanmaLibrariesfromENDF/B,"ORNL-TM-3706,OakRidgeNationalLaboratory,March1976.7.C.0.Brown,"CriticalitySafetyBenchmarkCalculationsforLow-EnrichedUraniumMetalandUraniumOxideRod-WaterLattices,"XN-NF-499,ExxonNuclearCompany,Inc.,April1979.8.J.L.Carter,Jr.,"HRG-3:ACode-for-CalculatingtheSlowing-DownSpectrumintheP1orB1Approximation,"BNWL-1432,Battelle-PacificNorthwestLaboratories,June1970.9.D.R.SkeenandL.J.Page,"THERMOS/BATTELLE:TheBattelleVersionoftheTHERMOSCode,"BNWL-516,Battelle-PacificNorthwestLaboratories,September1967.

12XN-NF-83-36,Rev.1.TableISt.LucieUnit1NominalFuelAssemblyParametersType:LatticePitch:CladO.D.:CladMaterial:ActiveFuelRods:No.ofControlRodGuideTubes:GuideTubeMaterial:GuideTubeO.D.:GuideTubeTk:Eff.ArrayDimension:ActiveFuelLength:CE14xl40.580inch0.440inchZr-41765Zr-41.115inch0.040inch8.12inchx8.12inch136.7inchCE14x14'\WWWWWWENC14xl4Enrichment,wtXPel]etOD,inchStackedFuelDensity,g/ccCladTk,inchModerator-to-FuelVolumeRatio(>)AxialU-235Loading,g/cmk(CCELL)3.70.376510.0540.0281.934'41.451.4474.0(assumed)0.370010.1990.0312.03443.91(2)1.462Thisratiotakesintoaccountthezirconiumtubingandwaterassociatedwiththeinstrumentandcontrolrodlocationswithinthefuelassembly.ThisvaluecorrespondstoanaxialU-235loadingat4.0wtXanddoesnotincludetheaxialblanketsofnaturaluranium.

13XN-NF-83-36,Rev.1TableIISt.LucieUnit1SpentFuelStoragePoolReactivitySensitivityCalculationResults(NITAML/XSDRNPH)CaseOescriptionNominalStorageArray6k~Comments1(base)Enrichment-4.0wtXTemperature-6BoFMallThickness-0.25"C-CSpacing-12.4375"NominalArrangement2a2bMallThickness-0.20"MallThickness-0.10"+0.0052+0.02493a3bC-CSpacing-12.0000"C-CSpacing-11.5625"+0.0199+0.0462Min.OffsetCondition

~*s1 rIse~14XN-NF-83-36,Rev.1/TableIIISt.LucieUnit1NewFuelStorageRoomReactivityCalculationResultsFuelAssembly:NumberofAssembliesinRoom:ArrayGeometry:CalculationModel:ENC14x14(4.0wtXU-235)80PerEbascoServicesDwgNo.8770-6-832,Rev.3KENOIVwith123groupcrosssectionspreparedusingNITAWL/XSDRNPHCaseVol%HaterinArraykeff+~Comnents2.55.010.015.00.825+0.0060.905+0.005(1)0.898+0.0060.811+0.006Max.CalculatedkeffPeakkeffestimatedtobeabout0.925(atthe95Kconfidencelevel)andtooccurbetween2.5and5.0vol%waterinthestoragearray.

}~~XN-NF-83-36,Rev.IAPPENDIXISECOND-PARTYREVIEMDOCUMENTATION

'i~~~HJ$84UGLEULRcoMPANY,Oc.internalCorrespondenceXN-NF-83-36Rev.1DistributionDate:To:From:

Subject:

May3,1983C.O.BrownJ.E.PieperCRITICALITYSAFETYANALYSISPORST.LUCIEUNIT1NEWANDSPENTFUELSTORAGE,XN>>NF-83-36Ref:A.S.Jameson(CanbustionEngineering)toR.W.Winnard(FloridaPowertLight),September18,1979,"BasesforUpdatingtheSt.Lucie-1TechnicalSpecification5.3.1".IhavecompletedarevievofthecalculationsandtheanalysisapproachusedinthestudyoftheSt.LucieUnit1new,spentfuelstorageandfuelinspectionelevator,upenderandtransfertube.Ibelievethatinconjunctionviththereferencedletter,youranalysisadequatelydeaan-stratesthecriticalitysafetyofExxonNuclear4.0vt.%Ufueldesignwhenusedinthisequipment.Thecross-sectionlibraryusedfortheanalysesveretracedthroughtheHITAWL,XSDRNPM,NITAWLcodestream.TheKENOandCCELLrunsverealsorevieved.Thefollovings~cificrunsvererevieved:CCELLNITAWLXSDRNPMNZTAWLZENDZVXSDRNPMXSDRNPMXSDRNPM'SDRNPMXSDRNPMXSDRNPMNZTAWLCCELLXENO-2CCELLCCELLCCELLCCELLNZTAWLNITAWLJobNameXCEL940NZTAWGEXSDRNMPNZT?lW81,KSTLUGQXSDRNRUXSDRHRXXSDRNROXSDRNRZXSDRN7UXSDRNDRNIT?LNH3XCE19LGKEN?2OZXCEL9LFXCEL9FUXCEL9LCXCE19LDNZTAWSTNZTAWSVDateofRun25/03/8328/03/8328/03/8328/03/8328/03/8305/04/8305/04/8305/04/8305/04/8304/04/8331/03/8331/03/8314/04/8319/04/8308/21/8305/04/8305/04/8305/04/8308/04/8307/04/83TimeofRun1255.1913344013.57.2715.26.4019.20.0620.42.172024.1020.46.1520.46.271929.2613.20.3612.57.2016.04.5319.54.0712.58.5811.56.451226.1712.26.1813.24.2117.25.33

~tgIc~C.O.archeXN-NF-83-36Rev.1May3,1983NIThWLNITAHLXSDRNPMXSDRNPMXSDRNPMXSDRNPMKENO-IVKENO-IVXENO-IVKENO-IVJobNameNIThWUONITKWSUXSDRNV1XSDRN9RXSDRNXBXSDRN95XSTLU2DXSTLUG3XSTLUSPKSTLUHLDateofRun06/04/83.07/04/8308/04/8307/04/8306/04/8307/04/8308/04/8307/04/8307/04/8307/04/83TimeofRun15.46.1417.25.3215.46.1417.44.2115.58.3117.44-3517.59.0222.15.3420.11.3422.15.36Thefollowingitems~eincludedinthereviewofthecodes:XENO:CCELLOptionsCorz'ectMixturesGeometryAdequateHistoriesCrossSections(DataorLihrarytape).effGeometryAtomDensitiesVerifiedResonanceTreatmentOptionsXNITASL:InputTapeOutputTapeZDRunnersResonanceParametersA>hereused)XSDRNPM:InputTapeOutputTapeGecxnetzyOptionsKQcturesConvergenceclc XN-NF-83-36,Rev.1IssueDate:2/28/86ST.LUCIEUNIT1NEMANDSPENTFUELSTORAGECRITICALITYSAFETYEVALUATIONFORNATURALURANIINAXIALBLANKETFUEL1.DISTRIBUTION0.C.Brown'L.D.GerraldT.J.Helbling(5)J.S.HolmT.M.PattenG.N.MardDocumentControl(2)

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