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.LUCIEUNIT1NEWANDSPENTFUELSTORAGECRITICALITY SAFETYEVALUATION FORNATURALURANIINAXIALBLANKETFUELPreparedby0.C.BrownFebruaryl986EONNUCLEARCOMPANY,INC.8b07150141 8b0708PDRADOCK05000355'"PDR XN-NF-83-36, Rev.1ST.LUCIEUNIT1NEWANDSPENTFUELSTORAGECRITICALITY SAFETYEVALUATION FORNATURALURANIUMAXIALBLANKETFUELPreparedby:rown,ngsneerBWRNeutronics aeApprovedby:'oy,arCorporate Licensing zanfaen,anagerNeutronics andFuelManagement jrs 0I XN-NF-83-36, Rev.1ST.LUCIEUNIT1NEWANDSPENTFUELSTORAGECRITICALITY SAFETYEVALUATION FORNATURALURANIUMAXIALBLANKETFUELTABLEOFCONTENTSSectionPage1.02.03.03.13.23.33.44.04.14.24.34.45.06.07.

08.0INTRODUCTION

..............................................

SUMMARYOFRESULTS........................................

SPENTFUELSTORAGEPOOLANALYSIS..........................

Design-BaseFuelAssemblyDescription

.....................

.StorageArrayDescription

.................................

StorageArrayReactivity

..................................

Concluslons

~~~~~~~~~~~~~~e~~~~~si~o~oo~~~~~~~o~~~~~~~~~~~~NEWFUELSTORAGEROOMANALYSIS............................

DesignBaseFuelAssemblyDescription

.....................

StorageArrayDescription

.................................

StorageArrayReactivity

..................................

COnC1us1OllS~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~o~FUELINSPECTION

ELEVATOR, UPENDER,ANDTRANSFERTUBE......CALCULATIONAL METHODS.....................................

COMPUTERMODELREVIEWANDVALIDATION

..............;.......

REFERENCES

.................................................

APPENDIX1-SECOND-PARTY REVIEWDOCUMENTATION 123333566667891011 XN-NF-83-36, Rev.1ST.LUCIEUNIT1NEWANDSPENTFUELSTORAGECRITICALITY SAFETYEVALUATION FORNATURALURANIUMAXIALBLANKETFUELLISTOFTABLESTablePageSt.LucieUnit1NominalFuelAssemblyParameters

.........

12SpentFuelStoragePoolReactivity Sensitivity Calculation Results...........'........................;...............

13NewFuelStorageRoomReactivity Calculation Results......14

)~l XN-NF-83-36, Rev.1ST.LUCIEUNIT1NEWANDSPENTFUELSTORAGECRITICALITY SAFETYEVALUATION FORNATURALURANIUMAXIALBLANKETFUEL

1.0INTRODUCTION

Thisreportsummarizes theresultsofthreecriticality safetyanalysesperformed forthehandlingandstorageofnewandspentfuelattheSt.LucieUnit1NuclearGenerating Station.Specifically, theanalysesaddressed thefollowing areas:1)SpentFuelPool(Section3.0)2)NewFuelStorageRacks(Section4.0)3)FuelInspection Elevation, Upender,andFuelTransferTube(Section5.0)AnExxonNuclearCompany(ENC)fuelassemblydesignwhichincludesnaturaluraniumaxialblanketsontheassemblyendsandacentralfuelregionenrichedtoamaximumof4.0wtXU-235wasassumedfortheanalyses.

Detaileddescriptions ofthehandlingandstorageareasisprovidedinthecriticality safetyevaluation reportsumnarized inReference 1.\

XN-NF-83-36, Rev.12.0SUMMARYOFRESULTSCalculations performed forthehandlingandstorageof4.0wtXU-235enrichedfuelassemblies externaltotheSt.LucieUnit1reactorcoreindicatethattheapplicable criticality safetycriteriaaremet.Worstcasereactivities calculated foreachareaareasfollows:AreaCalculated keff(95KCL)Limitingkeff(9NCL)CriteriaReference SpentFuelPoolNewFuelStorageRoomFuelElevator, Upender,TransferTube0.9180.9250.9240.950.980.95 3tXN-NF-83-36, Rev.I3.0SPENTFUELSTORAGEPOOLANALYSISThehighcapacity(HI-CAPŽ)

spentfuelstorageracksweredesignedtoaccomnodate 728fuelassemblies andaregenerally definedinAttachment AofReference I.3.1DesinBaseFuelAssemblyDescritionTheSt.LucieUnit1spentfuelstorageracksarecurrently designedandlicensedtoacceptfuelassemblies enrichedto3.7wtXU-235.TableIsummarizes fuelassemblyparameters forthisfueldesign,aswellasparame-tersfortheExxonNuclearfueldesign.AlsolistedinTableIarefuelassemblykcalculation resultsobtainedusingtheCCELL(4)computercode.(CCELLisapincellcalculation codeusedtocell-average resonance corrected crosssectiondataforinputintoothercodes,i.e.,KENO,etc.)Theseresultsindicatea+0.015bkchangeinfuelassemblyreactivity betweenthetwofueltypes.3.2StoraeArrayDescrition(SentFuelPoolAnalysis)

Thespentfuelstoragearraydesignanddimensions aredescribed indetailinReference 1.Thearrayconsistsofsquarestainless steelcanshavinganinsidedimension of8.4835inches.Thecanshaveanominalwallthickness of0.25inchesand-arefixedinasquare-pitched arrayonnominal12.53-inch centers.3.3StorageArrayReactivity (k)(SpentFuelPoolAnalysis)

ForthenominalstoragearraygeometrydefinedinSection3.2,keffwascalculated fortheExxonNuclearfuelenrichedto4.0wtX,U-235usingtheKENOIV(5)MonteCarlocomputercode.(CrosssectiondatafromtheXSDRN123-energy grouplibrarywerepreparedforinputintoKENOIVusingthe ll XN-NF-83-36, Rev.I,NITAWL(6) andXSDRNPM(6) codes.Adetaileddescription ofthecalculation methodisgiveninSection6.0.)Forapoolwatertemperature of68oF,akeffof0.874+0.005wascalculated assuminganeffectively infinitearray.Fromresultssummarized inReference I,a8<of+0.034hasbeenestablished betweenthenominalandworstcase(minimumoffset)storagearrayconditions.

ApplyingthishktotheKENO-calculated nominalkeffvalueresultsinaworstcasekffof0.918(*)atthe955confidence level.Forpostulated accidents suchasthedroppingofafuelassemblyontopoftheracksorhavinganassemblybyaccidentachieveanyotherabnormallocationinthepool,creditmaybetakenforrealistic initialpoolcondi-tions(2).

Theseconditions includetakingcreditforsolubleboron(>1720ppm)presentinthepoolwater.Atabout1700ppm,boronstoragearrayreactivity (keff)isreducedaPProximately 20%hk.Hence,Postulated accidents definedaboveareoflittleconcernfromacriticality safetystandpoint.

Tobetterunderstand thereactivity sensitivity ofthestoragearrangement tostainless steelcanwallthickness andfuelcellcenter-to-center spacing,severalcalculations wereperformed usingtheone-dimensional transport codeXSDRNPM.Acylindricized-equivalent nominalstoragecellwasmodeledwithareflective cellboundarytoapproximateaninfinitearray.Resultsofthesecalculations aresummarized inTableII.Forastainless steelcanwal1thickness decreaseof0.05inches,storagearrayreactivity increases about+0.005hk.Forastoragecellcenter-to-center spacingdecreasefrom12.4375inchesto12.0000inches,resultsindicateareactivity increaseofabout+0.020&.*keff(MC)=0.874+(2)(0.005)

+0.034=0.918(95Kconfidence level).

XN-NF-83-36, Rev.13.4Conclusions (SentFuelPoolAnalsis)Theresultsofthisanalysisdemonstrate thatExxonNucleardesignfueldefinedinTableIandenrichedto4.0wtXU-235canbestoredintheSt.LucieVnit1storagepoolandcontinuetomeetNRCcriticality safetycriteria, i.e.,theneutronmultiplication factorinthepoolshallbe(0.95underworstcredibleconditions.

Theadequacyofthecalculational methodsusedinthisanalysisisdiscussed inSection7.0.

XN-NF-83-36, Rev.14.0NEWFUELSTORAGEROOMANALYSISThenewfuelstoragearraywasanalyzedin1979(1)forCEfuelassemblies enrichedto3.70wtXU-235.Resultsofthisanalysisindicated themaximumstoragearrayreactivity (keff)tobeaboutG.92foralldegreesofuniformly interspersed moderation.

4.1DesinBaseFuelAssemblyDescription TheExxonNuclearfuelassemblydefinedinSection3.1andTableIwasusedinreactivity calculations forthenewfuelstoragearray.4.2StoraeArrayDescrition(NewFuelStoraeRoom)TheSt.LucieUnit1newfuelstorageroomconsistsofa10x10fuelassemblyarrayarrangement withthetwomiddlerows{runningnorthandsouth)removed.Theroomhasconcretewallsaroundtheentirearrayandcellsarespacedon21-inchcenters.Thefuelisnormallystoredinthedrycondition.

Additional detailsconcerning thearrangement canbefoundinAttachment BofReference 1.4.3StorageArrayReactivity (k)(NewFuelStorae)Sincethenewfuelisstoreddry,reactivity calculations wereperformed forvaryingdegreesofmoderation intheeventthearraybecamemoderated.

Forthecaseoffullflooding, thearraywouldremainsubcritical duetoneutronisolation betweenfuelassemblies.

Forthecaseofuniformmoderation interspersed withinandbetweenfuelassemblies inthestoragearray,i.e.,aqueousfoam,etc.,123energygroupKENO-IVcalculations wereperformed forwaterdensities inthearrayrangingfrom15%water(byvolume)to2.5X.Resultsofthesecalculations aresummarized inTableIIIandindicatethemaximumkeffofthearraytobe0.925atthe95Kconfidence level.

7XN-NF-83-36, Rev.14.4Conclusions (NewFuelStorae)Theresultssummarized inSection4.3andTableIII'emonstrate thatthemaximumkeffortheSt.LucieUnit1newfuelstorageroomwillnotexceedthelimitingcriterion of0.98foralldegreesofuniformmoderation inthearray.Specifically, themaximumreactivity occursforamoderator voidfractionbetween0.90and0.95andisestimated tobeabout0.925atthe95Kconfidence level.

XN-NF-83-36, Rev.15.0FUELINSPECTION

ELEVATOR, UPENDERANDTRANSFERTUBEForthefuelinspection

elevator, upenderandtransfertube,keffcalcula-tionswereperformed forthreeworstcasesituations inthepreviousevalua-tion,seeAttachment CofReference 1.Thecasewhichproducedthehighestreactivity involvedthefuelinspection elevator.

Forthiscase,itwasassumedthatonefuelassemblywasintheelevatorandoneadditional assemblywaslocatedfour(4)inchesedge-to-edge fromtheelevatorassembly.

Assumingthiscondition, aKENOcalculation wasperformed fortheExxonNuclearfuelassemblydefinedinTableI.Thiscasewasrunwith18energygroupcrosssectiondatapreparedusingCCELLandgavearesulting keffof0.914+0.005or0.924atthe95K,confidence level.Hence,itisconcluded that'thefuelinspection

elevator, upenderandtransfertubewillallmeetthekeff<0g5criterion forthe4.0wtXU-235enrichedfue'l.

0II' e9XN-NF-83-36, Rev.I6.0CALCULATIONAL METHODSTheKENO-IVMonteCarlocode(5)wasusedtocalculate thereactivities ofthestoragearraysandfuelelevator.

Multigroup crosssectiondatafromtheXSDRN123grouplibraryweregenerated forinputintoKENO-IVusingtheNITAWL(6) andXSDRNPM(6) codes.Specifically, theNITAWLcodewasutilizedtoobtaincrosssectiondataadjustedtoaccountforresonance self-shielding bytheNordheimIntegralMethod.TheXSDRNPMcode,adiscreteordinates one-dimensional transport theorycode,wasthenusedtopreparespatially cell-weighted crosssectiondatarepresentative ofthefuelassemblyforinputintoKENO-IV.Crosssectiondataforthefuelelevatorkeffcalcula-tionwerepreparedusingtheCCELLcode.CCELLisacombination oftheHRG(8)andTHERMOS(9) codes,andproducesmultigroup crosssectiondatatreatedinasimilarfashiontotheNITAWL/XSDRNPM methodology.

10XN-NF-83-36, Rev.17.0COMPUTERMODELREVIEWANDVALIDATION Thecalculated worstcasekeff(0.918)forthespentfuelstoragearrayisaboutAlessthanthecomparable valuefor3.7wtXfuel(0.947)reportedinReference 1.Thisisapparently duetoahighdegreeofconservatism intheReference 1calculational model.Thecomputercodemodelsusedforthecalculations inthisreporthavebeenbenchmarked againstexperimental dataandadequately reproduce thecriticalvalues.(Ontheaverage,thecriticalvalueisreproduced towithinonestandarddeviation.)

Detailedresultsofthesebenchmark calculations aregiveninReference 7.Inaddition, theresultsandconclusions ofthiscriticality safetyevaluation havebeensecond-party reviewedbyanindividual knowledgeable intheareaofcritical-itysafety.ThefindingsofthisreviewaregiveninAppendixI.

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

18.0REFERENCES

2.Letter(withattachments) fromR.E.Uhrig(FPL)toV;Stello(USNRC),"St.LucieUnit1DocketNo.50-335ProposedAmendment toFacilities Operating LicenseDPR-67,"datedOctober4,1979.LettertoallPowerReactorOperators fromB.K.Grimes(NRC),"OTPositionforReviewandAcceptance ofSpentFuelStorageandHandlingApplications,"

datedApril14,1978.3.AmericanNuclearSocietyStandard, ANS-N18.2.

4.W.W.Porath,"CCELLUsersGuide,"BNW/JN-86, PacificNorthwest Labora-tories,February1972.5.L.M.PetrieandN.F.Cross,"KENOIV:AnImprovedMonteCarloCriticality Program,"

ORNL-4938, OakRidgeNationalLaboratory, November1975.6.N.M.Green,et.al.,"AMPX-AModularCodeSystemforGenerating CoupledMultigr'oup Neutron-Ganma Libraries fromENDF/B,"ORNL-TM-3706, OakRidgeNationalLaboratory, March1976.7.C.0.Brown,"Criticality SafetyBenchmark Calculations forLow-Enriched UraniumMetalandUraniumOxideRod-Water Lattices,"

XN-NF-499, ExxonNuclearCompany,Inc.,April1979.8.J.L.Carter,Jr.,"HRG-3:ACode-for-Calculating theSlowing-Down SpectrumintheP1orB1Approximation,"

BNWL-1432, Battelle-Pacific Northwest Laboratories, June1970.9.D.R.SkeenandL.J.Page,"THERMOS/BATTELLE:

TheBattelleVersionoftheTHERMOSCode,"BNWL-516, Battelle-Pacific Northwest Laboratories, September 1967.

12XN-NF-83-36, Rev.1.TableISt.LucieUnit1NominalFuelAssemblyParameters Type: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-Fuel VolumeRatio(>)AxialU-235Loading,g/cmk(CCELL)3.70.376510.0540.0281.934'41.451.4474.0(assumed) 0.370010.1990.0312.03443.91(2)1.462Thisratiotakesintoaccountthezirconium tubingandwaterassociated withtheinstrument andcontrolrodlocations withinthefuelassembly.

Thisvaluecorresponds toanaxialU-235loadingat4.0wtXanddoesnotincludetheaxialblanketsofnaturaluranium.

13XN-NF-83-36, Rev.1TableIISt.LucieUnit1SpentFuelStoragePoolReactivity Sensitivity Calculation Results(NITAML/XSDRNPH)

CaseOescription NominalStorageArray6k~Comments1(base)Enrichment

-4.0wtXTemperature

-6BoFMallThickness

-0.25"C-CSpacing-12.4375"NominalArrangement 2a2bMallThickness

-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.LucieUnit1NewFuelStorageRoomReactivity Calculation ResultsFuelAssembly:

NumberofAssemblies inRoom:ArrayGeometry:

Calculation Model:ENC14x14(4.0wtXU-235)80PerEbascoServicesDwgNo.8770-6-832, Rev.3KENOIVwith123groupcrosssectionspreparedusingNITAWL/XSDRNPH CaseVol%HaterinArraykeff+~Comnents2.55.010.015.00.825+0.0060.905+0.005(1)0.898+0.0060.811+0.006Max.Calculated keffPeakkeffestimated tobeabout0.925(atthe95Kconfidence level)andtooccurbetween2.5and5.0vol%waterinthestoragearray.

}~~XN-NF-83-36, Rev.IAPPENDIXISECOND-PARTY REVIEMDOCUMENTATION

'i~~~HJ$84UGLEULRcoMPANY,Oc.

internalCorrespondence XN-NF-83-36 Rev.1Distribution Date:To:From:

Subject:

May3,1983C.O.BrownJ.E.PieperCRITICALITY SAFETYANALYSISPORST.LUCIEUNIT1NEWANDSPENTFUELSTORAGE,XN>>NF-83-36 Ref:A.S.Jameson(Canbustion Engineering) toR.W.Winnard(FloridaPowertLight),September 18,1979,"BasesforUpdatingtheSt.Lucie-1Technical Specification 5.3.1".Ihavecompleted arevievofthecalculations andtheanalysisapproachusedinthestudyoftheSt.LucieUnit1new,spentfuelstorageandfuelinspection

elevator, upenderandtransfertube.Ibelievethatinconjunction viththereferenced letter,youranalysisadequately deaan-stratesthecriticality safetyofExxonNuclear4.0vt.%Ufueldesignwhenusedinthisequipment.

Thecross-section libraryusedfortheanalysesveretracedthroughtheHITAWL,XSDRNPM,NITAWLcodestream.TheKENOandCCELLrunsverealsorevieved.

Thefolloving s~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-83-36 Rev.1May3,1983NIThWLNITAHLXSDRNPMXSDRNPMXSDRNPMXSDRNPMKENO-IVKENO-IVXENO-IVKENO-IVJobNameNIThWUONITKWSUXSDRNV1XSDRN9RXSDRNXBXSDRN95XSTLU2DXSTLUG3XSTLUSPKSTLUHLDateofRun06/04/83.07/04/83 08/04/8307/04/8306/04/8307/04/8308/04/8307/04/8307/04/8307/04/83TimeofRun15.46.1417.25.3215.46.1417.44.2115.58.3117.44-3517.59.0222.15.3420.11.3422.15.36Thefollowing items~eincludedinthereviewofthecodes:XENO:CCELLOptionsCorz'ectMixturesGeometryAdequateHistories CrossSections(DataorLihrarytape).effGeometryAtomDensities VerifiedResonance Treatment OptionsXNITASL:InputTapeOutputTapeZDRunnersResonance Parameters A>hereused)XSDRNPM:InputTapeOutputTapeGecxnetzy OptionsKQcturesConvergence clc XN-NF-83-36, Rev.1IssueDate:2/28/86ST.LUCIEUNIT1NEMANDSPENTFUELSTORAGECRITICALITY SAFETYEVALUATION FORNATURALURANIINAXIALBLANKETFUEL1.DISTRIBUTION 0.C.Brown'L.D.GerraldT.J.Helbling(5)J.S.HolmT.M.PattenG.N.MardDocumentControl(2)

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