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\'Page2A2III.DESIGNBASESA.Hulti1icationFactorThefuelstoragerackisdesignedtomeetthesubcriti~alitymarginspecifiedinSection5.1.12.1ofANSI-<<210-1976whichstatesinpart-"5.1.'2.1-"Thespentfuel'storageracksshallbedesionedtoassurethatakeffnotgreaterthan0,95ismaintainedwiththeracksfullyloadedwithfuelandfloodedwithunboratedwater.--Thedesignshallbe,basedonthemaximumenrich..ent.andfissileisotopic.contentoY'ueltobecycledintheplant.CLB.AssumtionsEmoloedinCriticalitEvaluationThefollowingassumptionsareemployedinthecriticalityevaluationtoassurethattheevaluationisconservativeovertherangeoffuelassemblydesignvariablesprovidedinthespecificationand/oranticipatedoperationalconditionsaffectingthecriticalitymarginofthespentfuelpool.1.Neutronleakageeffectsaretakentobethosecharacteristic~ofaninfinitearrayoffullyloaded,spentfuelstoracelocationsinthelateraldirectionsandinfinitelylongfuelassembliesandstorageboxwallsinthaxialdirection.Fortheanalysesofnormalspentfuellocationsemployingthereerence8.4835inchI.O.'stainlesssteelbox,aninfinitearrayofstoragecellshavinganominalsquaredimensionof12.53inchesisemployed.Intheseanalysesitisassumedthateachfuelstoragelocationcontainsafreshfuelassemblyofthelimitingenr.ichment(3.7w/oU-235).2.Parasiticneutroncapturecontributionsinthefuelstoragerackstructuralmaterialareconsirvativelyrepresentedbyneglectingallstructuralmaterialsotherthanthestainlesssteelboxwalls.3.Thespentfuel'poolisassu...edtobefloodedwithpure(unborate')wateratatemperatureof68oF.Elevatedcoolanttemperatureoffectsareassessedby'valuatingthereac:ivitychangebetweenisothermallatticecalcu-lationsat68and225F.10/4/79 Page30A-34.EachfuelassemblyisassumedtobeloadedwithunirradiatedUOghavinganenrichmentof3.7w/oU-235.Noburnablepoisonpins,controlrods,orneutronsourcesareassumedtobepresentinthefuelassemblies.'.,Parasiticneutroncapturecontributionsofstructuralcomponentsinthefuelassemblyareconservativelyrepresentedbyneglectingthezircaloyspacersleevesandgrids.A6.The,effectoffuelstoragerackmechanicaltolerancesandfuelassenklg;cfisplacementwithinthefuel.assemblystorageboxiscalculatedinaconservativefashionbyassumingtheltd'Wadverseconcurrentcombinationofdimensionaltolerancesandasimultanedusdiagonaldisplacementofthefuelassembliesineachclusteroffouradjacentstoragelocationssuchthateachfuelassemblyisincontactwithtwosidewallsofeachboxandthespacingbetweeneachpairofthefourfuelassembliesisminimized.ThemostadverseconcurrentcombinationofdimensionaltolerancescorrespondstoaconfigurationwhereintheCol'lowingconditionsexistineachcellofthestoragearray:(1)mimimumpitchbetweencenterlinesofadjacentfuelstorageboxes,(2)maximumstorageboxinternaldimensions,and(3)minimumboxwallthickness.IV.HI-CAP.PACKANALYSESAgeneraldescriptionofthefuelstoragerackinthespentfuelpoolisgiveninSectionIII.Thenominaldimensions2ofhenormalfuelstoragelocations,definedbyCEdrawingforthefinalreferencedesign,areasfollows:I.D.of304stainlesssteelbox,in.'.4835Thicknessof'teelbox,.in.Materchannel,in.Center-to-centerdistancein.0.253.54812.5312Thephysicalparametersforthefuelassemblysuchasfuelpinradiusanddensity,cellpitch,andccmpositionoiguidetubesaregiveninTableI.,Thecalculatedmultiplicationfactorforaninfinitearrayofnormal,fuelstoragelocations,eachcontainingonefuelassemblycenteredwithinth~.stainlesssteelbox,is0.8984.10/4/79 Page4A-4Todeterminethemostadverseeffectofmechanicaltolerancesonthemultiplicationfactor,theextremesintolerancesareusedratherthanastatisticalmodel.Thefollowingtolerancesandrestraintsapplytothenominaldimensionsofthefinalreferencedesign:I.D.ofsteelboxattopandbottom,in.Hinimumwaterchannel,in.Boxwallthickness,in.Boxwallbow,in.Center-to-centerspacingattop'ndbottomfromcornerofrack,lne+0.06252/64-0.01.and+0.047+.250+0.125Toassesstheeffectofdisplacementoffuelassemblieswithinthestorageboxesonthemultiplicationfactor,eachfuelassemblyisassumedtobedisplaceddiagonallyagainstthecornerofitsstorageboxinadirectionsuchthattheclosestdistanceofapproachisachievedwithineachclusteroffourstorageboxes.Rackdimensionsareassumedtobethosecorrespondingtotheminimumboxwallcase~examinedabove.Thecalculatedmultiplicationfactorforthiscaseis0.9324.Todeterminethereactivityat150Fand225Ffortheseanalysesallmaterialsanddimensionsincludingthecsnter-to-csnterspacingwereexpandedandthermalkernelsat150Fand225Fweree.:.ployedin,thscrosssections.Anadditionalcaseatnominaldimensionsat68Fwiththemorenormal1720ppmofdissolvedboronpresentwasalsorun.Thelasttwocasesareusedtodeterminetheworthofthsteelboxforanisolatedfloodedassembly.Thefollowingsuttmarizestheresultsofthesevencasesdiscussedabove.CaseBoxC-C~SacinBoxE.D.BoxMallThicknessYefeNominalCondition68F12.4375*8,4835Nominal68F,1720ppmboron12.43758.4835Isolated,withsteelbox32.98"8.48352HinimumOffsetCondition1'2.0000**8.66003Nominal150F12.44738.49024Nominal225F12.45638.49630.25"0.89830.24"0.93240.25006"0.89170.25011"Oe88360-25"0.67510.25"0.8075I7Isolated,nosteelbox32.98"<<Theanalyzedcenter-to-centernominalspacingisslightlysmallconstructedvalue.<<*Closestfuelassemblycenter-to-centerspacingis11.46".0.00"0.8728erthanthe10/4/79 | \'Page2A2III.DESIGNBASESA.Hulti1icationFactorThefuelstoragerackisdesignedtomeetthesubcriti~alitymarginspecifiedinSection5.1.12.1ofANSI-<<210-1976whichstatesinpart-"5.1.'2.1-"Thespentfuel'storageracksshallbedesionedtoassurethatakeffnotgreaterthan0,95ismaintainedwiththeracksfullyloadedwithfuelandfloodedwithunboratedwater.--Thedesignshallbe,basedonthemaximumenrich..ent.andfissileisotopic.contentoY'ueltobecycledintheplant.CLB.AssumtionsEmoloedinCriticalitEvaluationThefollowingassumptionsareemployedinthecriticalityevaluationtoassurethattheevaluationisconservativeovertherangeoffuelassemblydesignvariablesprovidedinthespecificationand/oranticipatedoperationalconditionsaffectingthecriticalitymarginofthespentfuelpool.1.Neutronleakageeffectsaretakentobethosecharacteristic~ofaninfinitearrayoffullyloaded,spentfuelstoracelocationsinthelateraldirectionsandinfinitelylongfuelassembliesandstorageboxwallsinthaxialdirection.Fortheanalysesofnormalspentfuellocationsemployingthereerence8.4835inchI.O.'stainlesssteelbox,aninfinitearrayofstoragecellshavinganominalsquaredimensionof12.53inchesisemployed.Intheseanalysesitisassumedthateachfuelstoragelocationcontainsafreshfuelassemblyofthelimitingenr.ichment(3.7w/oU-235).2.Parasiticneutroncapturecontributionsinthefuelstoragerackstructuralmaterialareconsirvativelyrepresentedbyneglectingallstructuralmaterialsotherthanthestainlesssteelboxwalls.3.Thespentfuel'poolisassu...edtobefloodedwithpure(unborate')wateratatemperatureof68oF.Elevatedcoolanttemperatureoffectsareassessedby'valuatingthereac:ivitychangebetweenisothermallatticecalcu-lationsat68and225F.10/4/79 Page30A-34.EachfuelassemblyisassumedtobeloadedwithunirradiatedUOghavinganenrichmentof3.7w/oU-235.Noburnablepoisonpins,controlrods,orneutronsourcesareassumedtobepresentinthefuelassemblies.'.,Parasiticneutroncapturecontributionsofstructuralcomponentsinthefuelassemblyareconservativelyrepresentedbyneglectingthezircaloyspacersleevesandgrids.A6.The,effectoffuelstoragerackmechanicaltolerancesandfuelassenklg;cfisplacementwithinthefuel.assemblystorageboxiscalculatedinaconservativefashionbyassumingtheltd'Wadverseconcurrentcombinationofdimensionaltolerancesandasimultanedusdiagonaldisplacementofthefuelassembliesineachclusteroffouradjacentstoragelocationssuchthateachfuelassemblyisincontactwithtwosidewallsofeachboxandthespacingbetweeneachpairofthefourfuelassembliesisminimized.ThemostadverseconcurrentcombinationofdimensionaltolerancescorrespondstoaconfigurationwhereintheCol'lowingconditionsexistineachcellofthestoragearray:(1)mimimumpitchbetweencenterlinesofadjacentfuelstorageboxes,(2)maximumstorageboxinternaldimensions,and(3)minimumboxwallthickness.IV.HI-CAP.PACKANALYSESAgeneraldescriptionofthefuelstoragerackinthespentfuelpoolisgiveninSectionIII.Thenominaldimensions2ofhenormalfuelstoragelocations,definedbyCEdrawingforthefinalreferencedesign,areasfollows:I.D.of304stainlesssteelbox,in.'.4835Thicknessof'teelbox,.in.Materchannel,in.Center-to-centerdistancein.0.253.54812.5312Thephysicalparametersforthefuelassemblysuchasfuelpinradiusanddensity,cellpitch,andccmpositionoiguidetubesaregiveninTableI.,Thecalculatedmultiplicationfactorforaninfinitearrayofnormal,fuelstoragelocations,eachcontainingonefuelassemblycenteredwithinth~.stainlesssteelbox,is0.8984.10/4/79 Page4A-4Todeterminethemostadverseeffectofmechanicaltolerancesonthemultiplicationfactor,theextremesintolerancesareusedratherthanastatisticalmodel.Thefollowingtolerancesandrestraintsapplytothenominaldimensionsofthefinalreferencedesign:I.D.ofsteelboxattopandbottom,in.Hinimumwaterchannel,in.Boxwallthickness,in.Boxwallbow,in.Center-to-centerspacingattop'ndbottomfromcornerofrack,lne+0.06252/64-0.01.and+0.047+.250+0.125Toassesstheeffectofdisplacementoffuelassemblieswithinthestorageboxesonthemultiplicationfactor,eachfuelassemblyisassumedtobedisplaceddiagonallyagainstthecornerofitsstorageboxinadirectionsuchthattheclosestdistanceofapproachisachievedwithineachclusteroffourstorageboxes.Rackdimensionsareassumedtobethosecorrespondingtotheminimumboxwallcase~examinedabove.Thecalculatedmultiplicationfactorforthiscaseis0.9324.Todeterminethereactivityat150Fand225Ffortheseanalysesallmaterialsanddimensionsincludingthecsnter-to-csnterspacingwereexpandedandthermalkernelsat150Fand225Fweree.:.ployedin,thscrosssections.Anadditionalcaseatnominaldimensionsat68Fwiththemorenormal1720ppmofdissolvedboronpresentwasalsorun.Thelasttwocasesareusedtodeterminetheworthofthsteelboxforanisolatedfloodedassembly.Thefollowingsuttmarizestheresultsofthesevencasesdiscussedabove.CaseBoxC-C~SacinBoxE.D.BoxMallThicknessYefeNominalCondition68F12.4375*8,4835Nominal68F,1720ppmboron12.43758.4835Isolated,withsteelbox32.98"8.48352HinimumOffsetCondition1'2.0000**8.66003Nominal150F12.44738.49024Nominal225F12.45638.49630.25"0.89830.24"0.93240.25006"0.89170.25011"Oe88360-25"0.67510.25"0.8075I7Isolated,nosteelbox32.98"<<Theanalyzedcenter-to-centernominalspacingisslightlysmallconstructedvalue.<<*Closestfuelassemblycenter-to-centerspacingis11.46".0.00"0.8728erthanthe10/4/79 | ||
~Page5Thecalculationaluncertaintiesusedinthisevaluationconsistof(1)a0.0053akeffuncertaintyderivedfromcomparisonsofcalculationsforaseriesofVO~experirimts,(2)abiasof0.0019inoverpredictingcriticalityinthe~eexperiments,and(3)abiasinthecalculatingsteelboxwallworthinferredfromcalculationsoftheJohnson-tiewlonexperiments3Themagnitudeofthelatterbiasisdeducedinthefollowingmanner.Theworthofthesteelboxwallstructurewhichisobtainedbysubtractingthkeffofcase6(0.8075)fromthatofcase7(0.8728)isfoundtobe0.0653akeff.Theanalysesofthe.Johnson-Newlonexperimntimpliedthatfortheadditionofa0.54cmthickstainlesssteelshelltotheuranylfluoridesolutioncontainer,theworthofsteelwasoverestimatdbyafactorof0.0041dividedby0.0239or0.172.,Thisfactortimesthecalculatedworthofsteelboxwalls(0.0653)inthestoragerackimpliesacalculationalbiasforthesteelof0.0112ak.Thereactivitybalanceforthecriticalityanalysisofthenormalspentfuelstoragelocationsissummarizedasfollows:HostadversecalculatedKeff+95/95confidencelevelcalculationaluncertainty+BiasV02(Experiment-Calculation)'+StainlessSteelCalculationalBias'.93240.0053-0.0019+0.01120.9470DesinConditionsHominall'.ostAdverseHultiplicationFactorforSpen'tFuelStorageRackExcessHargin0.89830.037'10.94?00.003010/4/79 | ~Page5Thecalculationaluncertaintiesusedinthisevaluationconsistof(1)a0.0053akeffuncertaintyderivedfromcomparisonsofcalculationsforaseriesofVO~experirimts,(2)abiasof0.0019inoverpredictingcriticalityinthe~eexperiments,and(3)abiasinthecalculatingsteelboxwallworthinferredfromcalculationsoftheJohnson-tiewlonexperiments3Themagnitudeofthelatterbiasisdeducedinthefollowingmanner.Theworthofthesteelboxwallstructurewhichisobtainedbysubtractingthkeffofcase6(0.8075)fromthatofcase7(0.8728)isfoundtobe0.0653akeff.Theanalysesofthe.Johnson-Newlonexperimntimpliedthatfortheadditionofa0.54cmthickstainlesssteelshelltotheuranylfluoridesolutioncontainer,theworthofsteelwasoverestimatdbyafactorof0.0041dividedby0.0239or0.172.,Thisfactortimesthecalculatedworthofsteelboxwalls(0.0653)inthestoragerackimpliesacalculationalbiasforthesteelof0.0112ak.Thereactivitybalanceforthecriticalityanalysisofthenormalspentfuelstoragelocationsissummarizedasfollows:HostadversecalculatedKeff+95/95confidencelevelcalculationaluncertainty+BiasV02(Experiment-Calculation)'+StainlessSteelCalculationalBias'.93240.0053-0.0019+0.01120.9470DesinConditionsHominall'.ostAdverseHultiplicationFactorforSpen'tFuelStorageRackExcessHargin0.89830.037'10.94?00.003010/4/79 | ||
~~~Page6A ReferencesAmricanNuclearSociety,StandardsConmitteehorkingGroupANS-57.2,"DesignObjectivesforLightlaterReactorSpentfuelStorageFacilitiesatNuclearPowerStations",ANSI-N210-1976,approvedApril12,1976.2.CEDrawing-.=.E-3077-667-002Rev.1,"SpentFuelRackllodule".,'ev.l,April11,1977.3.,Clark,R.H.,etal,PhysicsVerificationProgramFinalReportBKM-3647-3(Narch1967).10/4/79 1~~~~~~IITABLE1FUELASSEftBLYPARAMETERSFuelrodpitch.in.FuelrodarrayNumberoffuelrodsperassemblyFuelrodcladO.D.,in.FuelrodcladI.D.,in.FuelrodcladmaterialFuelpelletdiameter,incStackedfueldensity,gm/ccNumberofcontrolrod.guidetubesprassemblyGuidetubematerialGuidetubeO.D.,in.GuidetubeI.D.,in.0.5817604400.384Zircaloy-4.0.376510.054Zircaloy-41.1151.035FuelAssemblyActiveFeiHeight(in.)136.710/4/79 | ~~~Page6A-6-ReferencesAmricanNuclearSociety,StandardsConmitteehorkingGroupANS-57.2,"DesignObjectivesforLightlaterReactorSpentfuelStorageFacilitiesatNuclearPowerStations",ANSI-N210-1976,approvedApril12,1976.2.CEDrawing-.=.E-3077-667-002Rev.1,"SpentFuelRackllodule".,'ev.l,April11,1977.3.,Clark,R.H.,etal,PhysicsVerificationProgramFinalReportBKM-3647-3(Narch1967).10/4/79 1~~~~~~IITABLE1FUELASSEftBLYPARAMETERSFuelrodpitch.in.FuelrodarrayNumberoffuelrodsperassemblyFuelrodcladO.D.,in.FuelrodcladI.D.,in.FuelrodcladmaterialFuelpelletdiameter,incStackedfueldensity,gm/ccNumberofcontrolrod.guidetubesprassemblyGuidetubematerialGuidetubeO.D.,in.GuidetubeI.D.,in.0.5817604400.384Zircaloy-4.0.376510.054Zircaloy-41.1151.035FuelAssemblyActiveFeiHeight(in.)136.710/4/79 | ||
~~~IATTACHiviEi)T8FloridaPowerandLightNew5'uel.Storage-CriticalityEvaluationSulggary'URPOSE&RESULTS'hepurposeofthisdocumentistopresenttheresultsofacriticalityevaluationmadeinlg74insuppottofusingtheSt.Lucie-.lne~~i"elstoragerackf'r.fresh.Up2fuels.with.-enrich;:eats.upgo3.7yfgU235.Thenewfuelstorageracksconsistoftwoarraysof10x4spacesforfuelassembliesseparatedby'a42-inchwidespaceasshowninFigure1.Themaximumeffectiveneutronmultiplicationfactorunderconditionsofuniformwater(ofanydensity(1gm/cc)moderationinandbetweentheassembliesshouldmeettherequirementsofSection5.7.4.1ofANSN18.2whichstates:"Thedesignofspentfuelstorageracksandtransierequipmentshallbesuchthattheeffectivemultiplicationfacto~willnotexceed0.95withnewfuelofthehighestanticipatedenrichmentinplaceassumingflooding~vithpure'water.~Thedesignofnormaliy'drynewfuelstorageracksshallbesuchthattheeffectivemultiplicationfactorwillnotexceed0.98withfuelofthehighestanticipatedenrichmentinplaceassumingopiimummoderation(e.g.,auniformdensityaqueousfoamenvelopmentastheresultof'irefighing).Creditmaybetakenfortheinherentneutronabs'orbingeffectofr.aterialsofconstructionor,,iftherequirementsofCriterion5.7.5.10aremet,foraddednuclearpoisons."Typically,.histypeo,arrayhasareactivitypeakforfulldensitywateranda'econdarypeakinthev.aterdensityringeof0.03to0.2gm/cc.Therack,althoughnormallydrywithakeffofabout0.70,canbeimmersedinvariouswaterdensitiesthrouohirefighingfoams,floods,etc.Forfulldensitywaterthekeffis0.92,whichisvIellwithintherequirementsofamaximumkeffof0.95includingPnysicsuncertainties.Thisstudyusesfour-'grouptranspo."tcalculationsforwaterdensitiesrangingbetwen0.02and0.075gm/ccforthe<<wfuelrack,indicatirgamaximumkefofabout0.89.10/4/79 B-2Pag2Thephysicsuncertaintiesaremuchlargerforthselo:~density>Iaterystemsthanforfloodedsystems,sincenoapplicableexprimentshavebeenperformerd.Thecalculatedmaximumkeff'soabout0.9mouldallowforanuncertaintyof9.".tomeetthe0.98requirementsofAl)SN18.2.Thisisconsideredtabeadequate.ConditionsReuiredforCriticalitSafetThcalculationsperformedindicatethattho.oposeddrystoragearrangementsmeetthecriticalitysafetyrequ'cerementsofNtSStandardHlS2,withamarginofabout9;linkeffforlo:Idensity<;atersiderationconditions.Theproposedstoragearrangerentsare,therefore,"consideredtobesafe,subjecttothfolio.~ingconditions:l.Approvedstorageracksareused.2.3.leTheminimumsurface-to-surfacespacingsbet:~eenassembliesimpl":citintheanalyses,areenforcedinthe'ackspcifi-cations(seefollowingsection).CriticalitysafetyWithplutoniumrecyclefuelhasnotbeenestablished.TheenrichmentoftheU02assembliesislimitedto3.70woU235.10/4/79 I,)~I~.8-3Page3DISCUSSTONInitsevaluation,CEhasadoptedtheapproachofassessings'afetybasedontheminimumedge-to-edgespacingbetweenanytwoassemblies,takingintoaccountalldimensionaltolerancesandanticipateddeformationsduringearthquakes,etc.Onthisbasis,theminimumedge-to-edgespacingbetweenassemblieswouldbegreaterthan21.00-0.50(toleranceonpitch)-(815/16+1/16)=11.5inches,ratherthanthe21.00-8.2=12.8inchesimplicitintheanalyses.Itisestimated,thatthereductioninspacingof1.3inchesduetotolerances,plusanallowancefordefor,.ation(totalspacingreductionestimatedat1.5~inches)everywherewouldincreasetliemaximumkefftoabout0.916,whichwoulddecreasethenarginforPhysicsuncertaintiestoabout6...However,theminimumspacinginonepositionwouldusuallyimplyalargerspacingelsewhere,andthusthekeffcouldincreasetoonly.901.Therackdesignis,there-.ore,judgedtoprovideadequatecriticalitysafetymarginsforconditionsoffogmoderation.10/4/79 | ~~~IATTACHiviEi)T8FloridaPowerandLightNew5'uel.Storage-CriticalityEvaluationSulggary'URPOSE&RESULTS'hepurposeofthisdocumentistopresenttheresultsofacriticalityevaluationmadeinlg74insuppottofusingtheSt.Lucie-.lne~~i"elstoragerackf'r.fresh.Up2fuels.with.-enrich;:eats.upgo3.7yfgU235.Thenewfuelstorageracksconsistoftwoarraysof10x4spacesforfuelassembliesseparatedby'a42-inchwidespaceasshowninFigure1.Themaximumeffectiveneutronmultiplicationfactorunderconditionsofuniformwater(ofanydensity(1gm/cc)moderationinandbetweentheassembliesshouldmeettherequirementsofSection5.7.4.1ofANSN18.2whichstates:"Thedesignofspentfuelstorageracksandtransierequipmentshallbesuchthattheeffectivemultiplicationfacto~willnotexceed0.95withnewfuelofthehighestanticipatedenrichmentinplaceassumingflooding~vithpure'water.~Thedesignofnormaliy'drynewfuelstorageracksshallbesuchthattheeffectivemultiplicationfactorwillnotexceed0.98withfuelofthehighestanticipatedenrichmentinplaceassumingopiimummoderation(e.g.,auniformdensityaqueousfoamenvelopmentastheresultof'irefighing).Creditmaybetakenfortheinherentneutronabs'orbingeffectofr.aterialsofconstructionor,,iftherequirementsofCriterion5.7.5.10aremet,foraddednuclearpoisons."Typically,.histypeo,arrayhasareactivitypeakforfulldensitywateranda'econdarypeakinthev.aterdensityringeof0.03to0.2gm/cc.Therack,althoughnormallydrywithakeffofabout0.70,canbeimmersedinvariouswaterdensitiesthrouohirefighingfoams,floods,etc.Forfulldensitywaterthekeffis0.92,whichisvIellwithintherequirementsofamaximumkeffof0.95includingPnysicsuncertainties.Thisstudyusesfour-'grouptranspo."tcalculationsforwaterdensitiesrangingbetwen0.02and0.075gm/ccforthe<<wfuelrack,indicatirgamaximumkefofabout0.89.10/4/79 B-2Pag2Thephysicsuncertaintiesaremuchlargerforthselo:~density>Iaterystemsthanforfloodedsystems,sincenoapplicableexprimentshavebeenperformerd.Thecalculatedmaximumkeff'soabout0.9mouldallowforanuncertaintyof9.".tomeetthe0.98requirementsofAl)SN18.2.Thisisconsideredtabeadequate.ConditionsReuiredforCriticalitSafetThcalculationsperformedindicatethattho.oposeddrystoragearrangementsmeetthecriticalitysafetyrequ'cerementsofNtSStandardHlS2,withamarginofabout9;linkeffforlo:Idensity<;atersiderationconditions.Theproposedstoragearrangerentsare,therefore,"consideredtobesafe,subjecttothfolio.~ingconditions:l.Approvedstorageracksareused.2.3.leTheminimumsurface-to-surfacespacingsbet:~eenassembliesimpl":citintheanalyses,areenforcedinthe'ackspcifi-cations(seefollowingsection).CriticalitysafetyWithplutoniumrecyclefuelhasnotbeenestablished.TheenrichmentoftheU02assembliesislimitedto3.70woU235.10/4/79 I,)~I~.8-3Page3DISCUSSTONInitsevaluation,CEhasadoptedtheapproachofassessings'afetybasedontheminimumedge-to-edgespacingbetweenanytwoassemblies,takingintoaccountalldimensionaltolerancesandanticipateddeformationsduringearthquakes,etc.Onthisbasis,theminimumedge-to-edgespacingbetweenassemblieswouldbegreaterthan21.00-0.50(toleranceonpitch)-(815/16+1/16)=11.5inches,ratherthanthe21.00-8.2=12.8inchesimplicitintheanalyses.Itisestimated,thatthereductioninspacingof1.3inchesduetotolerances,plusanallowancefordefor,.ation(totalspacingreductionestimatedat1.5~inches)everywherewouldincreasetliemaximumkefftoabout0.916,whichwoulddecreasethenarginforPhysicsuncertaintiestoabout6...However,theminimumspacinginonepositionwouldusuallyimplyalargerspacingelsewhere,andthusthekeffcouldincreasetoonly.901.Therackdesignis,there-.ore,judgedtoprovideadequatecriticalitysafetymarginsforconditionsoffogmoderation.10/4/79 | ||
~~~~~~B-4s'+''Irr~r+o~~lr~f''~iL''..I1a5~~~r~rIIIaQI~/IIllIlIIllIereerr~.I,tI.rIrIr''/>g;eIgP+r.are,rcpa(r'y'gg(~~I10/4/79 ATTACH~ift<TCFloridaPower8LightFuelInspectionElevator.Upender,FuelTransferTubeCriticalityEvaluationSummaryPurose8ResultsThepurposeofthisdocumentistoprovideabasisforupdatingTechSpec5.3.1forSt.Lucie1fromanenrichmentof.3.1w/oto3.7w/obypresentingresultsofcriticalityanalysesforthefuelinspectionelevator,theupender,andthefueltransfertube.TheapplicablestandardAt<SI-H18.2(Reference1)section5.7.41statesinpart"Thedesignofspent-fuelstorageracksandtransferequipmentshallbesuchthattheeffectivemulti-plicationfactorwillnotexceed0.95withnewfuelofthehighestanticipatedenrichmentinplaceassumingfloodingwithpurewater,"Thehighestreactivitysituation',assumingatleastafourinchstandofftolimittheapproachofasecondassembly,is0.911,thusallowingamarginofmorethan0.03akbeyondtheallowanceforcalculational.uncertaintiesdeterminedbythe.analysisofawidevarietyofcriticalexperiments.DesinInoutThefueldimensionsanddensitiesforthe14x14pinasser,blyaretakenfromtheSt.Lucie1FSARusinga'3.7w/oU-235enrichment.n,ThefuelelevatordimensionsarebasedonProgrammedandRemoteSystemsCorp.Drawing-;.'-15699-0,Rev.8dated6/29/78oftheelevatorcarriage.Standoffsappear.intheEbascodrawing8770-6841Rev.1toatleastpartiallypreventasecondassemblyfromapproachingcloserthanateninchedgetoedgeseparation.Thesteelstructureviasignoredinthisanalyses.10/4/79 | ~~~~~~B-4s'+''Irr~r+o~~lr~f''~iL''..I1a5~~~r~rIIIaQI~/IIllIlIIllIereerr~.I,tI.rIrIr''/>g;eIgP+r.are,rcpa(r'y'gg(~~I10/4/79 ATTACH~ift<TCFloridaPower8LightFuelInspectionElevator.Upender,FuelTransferTubeCriticalityEvaluationSummaryPurose8ResultsThepurposeofthisdocumentistoprovideabasisforupdatingTechSpec5.3.1forSt.Lucie1fromanenrichmentof.3.1w/oto3.7w/obypresentingresultsofcriticalityanalysesforthefuelinspectionelevator,theupender,andthefueltransfertube.TheapplicablestandardAt<SI-H18.2(Reference1)section5.7.41statesinpart"Thedesignofspent-fuelstorageracksandtransferequipmentshallbesuchthattheeffectivemulti-plicationfactorwillnotexceed0.95withnewfuelofthehighestanticipatedenrichmentinplaceassumingfloodingwithpurewater,"Thehighestreactivitysituation',assumingatleastafourinchstandofftolimittheapproachofasecondassembly,is0.911,thusallowingamarginofmorethan0.03akbeyondtheallowanceforcalculational.uncertaintiesdeterminedbythe.analysisofawidevarietyofcriticalexperiments.DesinInoutThefueldimensionsanddensitiesforthe14x14pinasser,blyaretakenfromtheSt.Lucie1FSARusinga'3.7w/oU-235enrichment.n,ThefuelelevatordimensionsarebasedonProgrammedandRemoteSystemsCorp.Drawing-;.'-15699-0,Rev.8dated6/29/78oftheelevatorcarriage.Standoffsappear.intheEbascodrawing8770-6841Rev.1toatleastpartiallypreventasecondassemblyfromapproachingcloserthanateninchedgetoedgeseparation.Thesteelstructureviasignoredinthisanalyses.10/4/79 | ||
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| Site: | Saint Lucie  |
| Issue date: | 10/04/1979 |
| From: | FLORIDA POWER & LIGHT CO. |
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DESIGNFEATURES5.2.1.2SHIELDBUILDINGa.C.Minimumannularspace=4feet.Annulusnominalvolume=543,000cubiceet.Nominaloutsideheight(measured=romtopoffoundationbasetothetopofthedome)=230.5eet.<<std.Nominalinsidediameer=148feet.e.Cylinderwallminimumthickness=3feet.Domeminimumthickness=2.5feet.Domeinsideradius=112feet.DESIGNPRESSURE.ANDTEHPERATURE5.2.2Thecontainmentvesselisdesignedandshallbemaintainedforamaximuminternalpressureof44psigandatemperature.ofZ64'F.PENETRATION55.2.3Penetrationsthroughthecontainmentstructurearedesignedandshallbemaintainedinaccordancewithheoriginaldesignpro-visionscontainedinSections3.8.2.1.10and6.2.4oftheFSARwithallowance=ornormaldegradationpursuanttotheapplicableSurveillanceRequirements.5.3REACTORCOREFUELASSEHBLIES5.3.1Thereactorcoreshallcontain217fuelassemblieswitheach-;uelassemblycon.ainingamaximumof176fuelrodscladwithZircoloy-4.Eachfuelrodsha':1haveanominalactivefuel1ngthof136.7inchesandcontainamaxiimumtotalweightof2250gramsuranium.Thiniialcoreloadingshallhaveamaximumenrichmentof2.83weightpercentU-235.Reloadfuelshallbesimilarinphvsicaldesignto.heinitialcoreloadingandshallhavemaximumenrihmentof3.7weightpercentU-Z35.ST.LUCIE-UNIT1V9~O~S0~~~!10/4/79 SAFETYEVALUATIONRe:St.LucieUnitlDocketNo.50-335FuelAssemblEnrichmentAttachmentA:Spent.FuelStorageRack-CriticalityEvaluationSummaryAttachmentB:NewFuelStorage-CriticalityEvaluationSummaryAttachmentC:FuelInspectionElevator,Upender,&FuelTransferTube-CriticalityEvaluationSummary10/4/79 ATTACHMENTAFloridaPower8LightSpentFuelPoolStorageRackCriticalityEvaluationSummaryI.PURPOSE8RESULTSThisreportpresentsasummaryofthecriticalityevaluationofthehighcapacity(HI-CAPT<')fuelstoragerackdesignedtoacccnodate728fuelassembliesinfuelstoragelocationsinthespentfvelpool,attheSt.LucieNuclearStation,Unit1Byvirtueoftheconservativeassumptionsemployedinthecriticalityevaluation,itisconcludedthatunder.normaloperatingconditionsandwithalimitingUOpfeedenrichmentof3.7w/oU-235,themultiplicationfactorof'liefullyloadedrackinthefloodedspentfuelpooldoesnotexceedthelimitingmultiplicationactorof0.95specifiedinA".lSI-i'(210-1976.Thisconclusionisbasedontheresultsofanalyseswhichpredictamultiplicationfactorof0.947'ortherackwhenfullyloadedwithfreshfuelof.thelimitingenrichmntandimmersedinpurewaterat68oF,includingallowancesforcalculationaluncertaintiesandbiases.Theseanalyseseci.ployarraysofstoragecellsthatareofinfiniteextentinboththelateralandaxialdirections,andincludetheeffectsofthemostadversecombinationofmechanicaltolerancesandfueldisplacement.Increasingtnecoolanttemperaturefrom68to225Fdecreasesthemultiplicationfactorby0.015.DISCUSSIOriThisreportprovidesadescriptionofthecriticalityevalvationofthehighcapacityfuelstorageracksdesignedandmanufacturedbyCombustionEngineering,Inc.forinstallationinthespenifuelpooloftheSt.LucielluclearStation,Unit.1.Thisrackdesignprovides728normalstoragelocations.Eachstoragelocationisdesignedtoaccommodateonefuelassenblyconsistingof176fvelrods,and5controlrodguidetubesina14x14arraywithanominalpitchof0.580inches.ThefuelstoragelocationsareoftheHI-CAPdesign>which,forthisTHapplication,consistsofatype304stainlesssteelboxstructurehavingasquarecrosssectionalgeocetrywithanominalinternaldi-..ensionof8.4835inches.,Theboxwallswhichcompletelyenclosethefourverticalsidesofafuelassemblyhaveanominalthicknesso0.250inches.Thenoninatcentertocenterspacingof12.53inchesforeachfuelstorag.box,andthenominalwatergapthicknessof3.548inchesbetween.adjacentboxes,aremaintainedwithinspecifiedtolerancesbystructuralmembersweldedtotheexteriorsurfacesoftheboxes.Subsequertsectionsofthisreportdiscussthedesignbasesandresultsofthcri.icalityevalvation.10/4/79
\'Page2A2III.DESIGNBASESA.Hulti1icationFactorThefuelstoragerackisdesignedtomeetthesubcriti~alitymarginspecifiedinSection5.1.12.1ofANSI-<<210-1976whichstatesinpart-"5.1.'2.1-"Thespentfuel'storageracksshallbedesionedtoassurethatakeffnotgreaterthan0,95ismaintainedwiththeracksfullyloadedwithfuelandfloodedwithunboratedwater.--Thedesignshallbe,basedonthemaximumenrich..ent.andfissileisotopic.contentoY'ueltobecycledintheplant.CLB.AssumtionsEmoloedinCriticalitEvaluationThefollowingassumptionsareemployedinthecriticalityevaluationtoassurethattheevaluationisconservativeovertherangeoffuelassemblydesignvariablesprovidedinthespecificationand/oranticipatedoperationalconditionsaffectingthecriticalitymarginofthespentfuelpool.1.Neutronleakageeffectsaretakentobethosecharacteristic~ofaninfinitearrayoffullyloaded,spentfuelstoracelocationsinthelateraldirectionsandinfinitelylongfuelassembliesandstorageboxwallsinthaxialdirection.Fortheanalysesofnormalspentfuellocationsemployingthereerence8.4835inchI.O.'stainlesssteelbox,aninfinitearrayofstoragecellshavinganominalsquaredimensionof12.53inchesisemployed.Intheseanalysesitisassumedthateachfuelstoragelocationcontainsafreshfuelassemblyofthelimitingenr.ichment(3.7w/oU-235).2.Parasiticneutroncapturecontributionsinthefuelstoragerackstructuralmaterialareconsirvativelyrepresentedbyneglectingallstructuralmaterialsotherthanthestainlesssteelboxwalls.3.Thespentfuel'poolisassu...edtobefloodedwithpure(unborate')wateratatemperatureof68oF.Elevatedcoolanttemperatureoffectsareassessedby'valuatingthereac:ivitychangebetweenisothermallatticecalcu-lationsat68and225F.10/4/79 Page30A-34.EachfuelassemblyisassumedtobeloadedwithunirradiatedUOghavinganenrichmentof3.7w/oU-235.Noburnablepoisonpins,controlrods,orneutronsourcesareassumedtobepresentinthefuelassemblies.'.,Parasiticneutroncapturecontributionsofstructuralcomponentsinthefuelassemblyareconservativelyrepresentedbyneglectingthezircaloyspacersleevesandgrids.A6.The,effectoffuelstoragerackmechanicaltolerancesandfuelassenklg;cfisplacementwithinthefuel.assemblystorageboxiscalculatedinaconservativefashionbyassumingtheltd'Wadverseconcurrentcombinationofdimensionaltolerancesandasimultanedusdiagonaldisplacementofthefuelassembliesineachclusteroffouradjacentstoragelocationssuchthateachfuelassemblyisincontactwithtwosidewallsofeachboxandthespacingbetweeneachpairofthefourfuelassembliesisminimized.ThemostadverseconcurrentcombinationofdimensionaltolerancescorrespondstoaconfigurationwhereintheCol'lowingconditionsexistineachcellofthestoragearray:(1)mimimumpitchbetweencenterlinesofadjacentfuelstorageboxes,(2)maximumstorageboxinternaldimensions,and(3)minimumboxwallthickness.IV.HI-CAP.PACKANALYSESAgeneraldescriptionofthefuelstoragerackinthespentfuelpoolisgiveninSectionIII.Thenominaldimensions2ofhenormalfuelstoragelocations,definedbyCEdrawingforthefinalreferencedesign,areasfollows:I.D.of304stainlesssteelbox,in.'.4835Thicknessof'teelbox,.in.Materchannel,in.Center-to-centerdistancein.0.253.54812.5312Thephysicalparametersforthefuelassemblysuchasfuelpinradiusanddensity,cellpitch,andccmpositionoiguidetubesaregiveninTableI.,Thecalculatedmultiplicationfactorforaninfinitearrayofnormal,fuelstoragelocations,eachcontainingonefuelassemblycenteredwithinth~.stainlesssteelbox,is0.8984.10/4/79 Page4A-4Todeterminethemostadverseeffectofmechanicaltolerancesonthemultiplicationfactor,theextremesintolerancesareusedratherthanastatisticalmodel.Thefollowingtolerancesandrestraintsapplytothenominaldimensionsofthefinalreferencedesign:I.D.ofsteelboxattopandbottom,in.Hinimumwaterchannel,in.Boxwallthickness,in.Boxwallbow,in.Center-to-centerspacingattop'ndbottomfromcornerofrack,lne+0.06252/64-0.01.and+0.047+.250+0.125Toassesstheeffectofdisplacementoffuelassemblieswithinthestorageboxesonthemultiplicationfactor,eachfuelassemblyisassumedtobedisplaceddiagonallyagainstthecornerofitsstorageboxinadirectionsuchthattheclosestdistanceofapproachisachievedwithineachclusteroffourstorageboxes.Rackdimensionsareassumedtobethosecorrespondingtotheminimumboxwallcase~examinedabove.Thecalculatedmultiplicationfactorforthiscaseis0.9324.Todeterminethereactivityat150Fand225Ffortheseanalysesallmaterialsanddimensionsincludingthecsnter-to-csnterspacingwereexpandedandthermalkernelsat150Fand225Fweree.:.ployedin,thscrosssections.Anadditionalcaseatnominaldimensionsat68Fwiththemorenormal1720ppmofdissolvedboronpresentwasalsorun.Thelasttwocasesareusedtodeterminetheworthofthsteelboxforanisolatedfloodedassembly.Thefollowingsuttmarizestheresultsofthesevencasesdiscussedabove.CaseBoxC-C~SacinBoxE.D.BoxMallThicknessYefeNominalCondition68F12.4375*8,4835Nominal68F,1720ppmboron12.43758.4835Isolated,withsteelbox32.98"8.48352HinimumOffsetCondition1'2.0000**8.66003Nominal150F12.44738.49024Nominal225F12.45638.49630.25"0.89830.24"0.93240.25006"0.89170.25011"Oe88360-25"0.67510.25"0.8075I7Isolated,nosteelbox32.98"<<Theanalyzedcenter-to-centernominalspacingisslightlysmallconstructedvalue.<<*Closestfuelassemblycenter-to-centerspacingis11.46".0.00"0.8728erthanthe10/4/79
~Page5Thecalculationaluncertaintiesusedinthisevaluationconsistof(1)a0.0053akeffuncertaintyderivedfromcomparisonsofcalculationsforaseriesofVO~experirimts,(2)abiasof0.0019inoverpredictingcriticalityinthe~eexperiments,and(3)abiasinthecalculatingsteelboxwallworthinferredfromcalculationsoftheJohnson-tiewlonexperiments3Themagnitudeofthelatterbiasisdeducedinthefollowingmanner.Theworthofthesteelboxwallstructurewhichisobtainedbysubtractingthkeffofcase6(0.8075)fromthatofcase7(0.8728)isfoundtobe0.0653akeff.Theanalysesofthe.Johnson-Newlonexperimntimpliedthatfortheadditionofa0.54cmthickstainlesssteelshelltotheuranylfluoridesolutioncontainer,theworthofsteelwasoverestimatdbyafactorof0.0041dividedby0.0239or0.172.,Thisfactortimesthecalculatedworthofsteelboxwalls(0.0653)inthestoragerackimpliesacalculationalbiasforthesteelof0.0112ak.Thereactivitybalanceforthecriticalityanalysisofthenormalspentfuelstoragelocationsissummarizedasfollows:HostadversecalculatedKeff+95/95confidencelevelcalculationaluncertainty+BiasV02(Experiment-Calculation)'+StainlessSteelCalculationalBias'.93240.0053-0.0019+0.01120.9470DesinConditionsHominall'.ostAdverseHultiplicationFactorforSpen'tFuelStorageRackExcessHargin0.89830.037'10.94?00.003010/4/79
~~~Page6A-6-ReferencesAmricanNuclearSociety,StandardsConmitteehorkingGroupANS-57.2,"DesignObjectivesforLightlaterReactorSpentfuelStorageFacilitiesatNuclearPowerStations",ANSI-N210-1976,approvedApril12,1976.2.CEDrawing-.=.E-3077-667-002Rev.1,"SpentFuelRackllodule".,'ev.l,April11,1977.3.,Clark,R.H.,etal,PhysicsVerificationProgramFinalReportBKM-3647-3(Narch1967).10/4/79 1~~~~~~IITABLE1FUELASSEftBLYPARAMETERSFuelrodpitch.in.FuelrodarrayNumberoffuelrodsperassemblyFuelrodcladO.D.,in.FuelrodcladI.D.,in.FuelrodcladmaterialFuelpelletdiameter,incStackedfueldensity,gm/ccNumberofcontrolrod.guidetubesprassemblyGuidetubematerialGuidetubeO.D.,in.GuidetubeI.D.,in.0.5817604400.384Zircaloy-4.0.376510.054Zircaloy-41.1151.035FuelAssemblyActiveFeiHeight(in.)136.710/4/79
~~~IATTACHiviEi)T8FloridaPowerandLightNew5'uel.Storage-CriticalityEvaluationSulggary'URPOSE&RESULTS'hepurposeofthisdocumentistopresenttheresultsofacriticalityevaluationmadeinlg74insuppottofusingtheSt.Lucie-.lne~~i"elstoragerackf'r.fresh.Up2fuels.with.-enrich;:eats.upgo3.7yfgU235.Thenewfuelstorageracksconsistoftwoarraysof10x4spacesforfuelassembliesseparatedby'a42-inchwidespaceasshowninFigure1.Themaximumeffectiveneutronmultiplicationfactorunderconditionsofuniformwater(ofanydensity(1gm/cc)moderationinandbetweentheassembliesshouldmeettherequirementsofSection5.7.4.1ofANSN18.2whichstates:"Thedesignofspentfuelstorageracksandtransierequipmentshallbesuchthattheeffectivemultiplicationfacto~willnotexceed0.95withnewfuelofthehighestanticipatedenrichmentinplaceassumingflooding~vithpure'water.~Thedesignofnormaliy'drynewfuelstorageracksshallbesuchthattheeffectivemultiplicationfactorwillnotexceed0.98withfuelofthehighestanticipatedenrichmentinplaceassumingopiimummoderation(e.g.,auniformdensityaqueousfoamenvelopmentastheresultof'irefighing).Creditmaybetakenfortheinherentneutronabs'orbingeffectofr.aterialsofconstructionor,,iftherequirementsofCriterion5.7.5.10aremet,foraddednuclearpoisons."Typically,.histypeo,arrayhasareactivitypeakforfulldensitywateranda'econdarypeakinthev.aterdensityringeof0.03to0.2gm/cc.Therack,althoughnormallydrywithakeffofabout0.70,canbeimmersedinvariouswaterdensitiesthrouohirefighingfoams,floods,etc.Forfulldensitywaterthekeffis0.92,whichisvIellwithintherequirementsofamaximumkeffof0.95includingPnysicsuncertainties.Thisstudyusesfour-'grouptranspo."tcalculationsforwaterdensitiesrangingbetwen0.02and0.075gm/ccforthe<<wfuelrack,indicatirgamaximumkefofabout0.89.10/4/79 B-2Pag2Thephysicsuncertaintiesaremuchlargerforthselo:~density>Iaterystemsthanforfloodedsystems,sincenoapplicableexprimentshavebeenperformerd.Thecalculatedmaximumkeff'soabout0.9mouldallowforanuncertaintyof9.".tomeetthe0.98requirementsofAl)SN18.2.Thisisconsideredtabeadequate.ConditionsReuiredforCriticalitSafetThcalculationsperformedindicatethattho.oposeddrystoragearrangementsmeetthecriticalitysafetyrequ'cerementsofNtSStandardHlS2,withamarginofabout9;linkeffforlo:Idensity<;atersiderationconditions.Theproposedstoragearrangerentsare,therefore,"consideredtobesafe,subjecttothfolio.~ingconditions:l.Approvedstorageracksareused.2.3.leTheminimumsurface-to-surfacespacingsbet:~eenassembliesimpl":citintheanalyses,areenforcedinthe'ackspcifi-cations(seefollowingsection).CriticalitysafetyWithplutoniumrecyclefuelhasnotbeenestablished.TheenrichmentoftheU02assembliesislimitedto3.70woU235.10/4/79 I,)~I~.8-3Page3DISCUSSTONInitsevaluation,CEhasadoptedtheapproachofassessings'afetybasedontheminimumedge-to-edgespacingbetweenanytwoassemblies,takingintoaccountalldimensionaltolerancesandanticipateddeformationsduringearthquakes,etc.Onthisbasis,theminimumedge-to-edgespacingbetweenassemblieswouldbegreaterthan21.00-0.50(toleranceonpitch)-(815/16+1/16)=11.5inches,ratherthanthe21.00-8.2=12.8inchesimplicitintheanalyses.Itisestimated,thatthereductioninspacingof1.3inchesduetotolerances,plusanallowancefordefor,.ation(totalspacingreductionestimatedat1.5~inches)everywherewouldincreasetliemaximumkefftoabout0.916,whichwoulddecreasethenarginforPhysicsuncertaintiestoabout6...However,theminimumspacinginonepositionwouldusuallyimplyalargerspacingelsewhere,andthusthekeffcouldincreasetoonly.901.Therackdesignis,there-.ore,judgedtoprovideadequatecriticalitysafetymarginsforconditionsoffogmoderation.10/4/79
~~~~~~B-4s'+Irr~r+o~~lr~f~iL..I1a5~~~r~rIIIaQI~/IIllIlIIllIereerr~.I,tI.rIrIr/>g;eIgP+r.are,rcpa(r'y'gg(~~I10/4/79 ATTACH~ift<TCFloridaPower8LightFuelInspectionElevator.Upender,FuelTransferTubeCriticalityEvaluationSummaryPurose8ResultsThepurposeofthisdocumentistoprovideabasisforupdatingTechSpec5.3.1forSt.Lucie1fromanenrichmentof.3.1w/oto3.7w/obypresentingresultsofcriticalityanalysesforthefuelinspectionelevator,theupender,andthefueltransfertube.TheapplicablestandardAt<SI-H18.2(Reference1)section5.7.41statesinpart"Thedesignofspent-fuelstorageracksandtransferequipmentshallbesuchthattheeffectivemulti-plicationfactorwillnotexceed0.95withnewfuelofthehighestanticipatedenrichmentinplaceassumingfloodingwithpurewater,"Thehighestreactivitysituation',assumingatleastafourinchstandofftolimittheapproachofasecondassembly,is0.911,thusallowingamarginofmorethan0.03akbeyondtheallowanceforcalculational.uncertaintiesdeterminedbythe.analysisofawidevarietyofcriticalexperiments.DesinInoutThefueldimensionsanddensitiesforthe14x14pinasser,blyaretakenfromtheSt.Lucie1FSARusinga'3.7w/oU-235enrichment.n,ThefuelelevatordimensionsarebasedonProgrammedandRemoteSystemsCorp.Drawing-;.'-15699-0,Rev.8dated6/29/78oftheelevatorcarriage.Standoffsappear.intheEbascodrawing8770-6841Rev.1toatleastpartiallypreventasecondassemblyfromapproachingcloserthanateninchedgetoedgeseparation.Thesteelstructureviasignoredinthisanalyses.10/4/79
+~~,<a%'
1~~~e'h~~sJ.e0C-2TheupenderdimensionsarebasedonP.R.S.C.DrawinqPA-13594-DRev.0of1971fortheFuelCarrierAssemblyandindicatethattheclosest'pproach,if,twoassembliesareinthecarrierassembly,is413/16inchesandalsothepresenceoffour2x2xl/8inchstainlesssteelfulllengthanqlesatthecornerofeachassembly.Thefueltransfertubeinnerradiusof35.25incheswasobtainedfromP.R.S.C.Orawinq"-'l-13~99-0,Rev.Edated7-28-76qftheFuelTranserTubeRailassemblyInstallation.Inallcasesnon-borated.wateratroomtemperaturewasassm~edalthoughnormallyafewthousandPPl1ofdisso1vedboronarepresent.DiscussionandResultsInordertomoreaccuratelypredictthemultiplicationfactoro,theassembly.arrays,reliablecalculationsoftiespatialfluxdistribuion,.esoeciallyintheneutronabsorbingstelregions,areessential.Forthisreason,atwodimensionaltransaortcalculationmod1ofthetrans-.fersystemisemployedin>>hicheachcomponentofthefueltransfersystemqeometryisexplicitlyreoresented.Thus,inthefuelupendercalculation,thefuelassemblies,thewaterchannelbet:.'eenthefuel-assemblies,thesteelangles,andthewaterreflectorarereoresentedasseparateregions.Thefuelassemblyitsel=isrepresentedasa1'.xl4arravoffuelassemblvcellscontainingmoderatorandeitherfuelpinsorguidetubes.Fourneutrongroupcrosssectionsaregenera~ed~ore.chfuelassemblycellandf'reachcomponentofthesystemwithspecialattentionqiventotheeffectofadjoiningregionsonthespatialt:".rmalspectrumandhencebroadgroupthermalcrosssectionsofeachseparateregion.'Themostreactivesituationofthethreeconsideredwouldbeforthefuelelevatorwhenasecondfuelassemblyisassumed'obealignedwiththeoneintheelevatorwithanedgetoedqespacirgof.fourinches,i'eresultinakeffis0.911.-Fortheuoenderthemostreactivesituation.".ouldbewhenathirdasse;..blJaooroachestowithinourinches(edgetoedqe)of'hetwoasse-bliesintheupendr;thekeffforthissituationis0.899.Thiskerfislessthanforth'etwoassembliesseoaratedbysamedistanceintheelevatorbcausethesteelanqlesateachcornerofbothassembliesintheupenderwereinc1udedinthean'alyses.Thereac.ivityofthefuelarrayinthetransertubewillbeless-..'.an-.orthecaseo<theupender,i.e.akeffof(0.8'99.ThereasonbeingcnlJtwofuelasserbliescanbeinthetransf'ertubeandtheu~lismaintainedinthesaveconfiquratiooasintheupender;athirdassemblycannota"proachthetwoassemblieswhileinthetransfertube.10/4/79 C-3Theabovemultiplicationfactorsarevalidenvelopvaluesforaminimumseparationbetweenathirdassemblyfortheupenderandasecondassemblyforthefuelelevatoroffourinchesorgreater.
Reference:
l.AmericanNationalStandardsInstitute"NuclearSafetyCriteriafortheDesignofStationandPressurizedHaterReactorPlants,"ANSI-N18.2-1973,August6,1973.10/4/79 4y.t~4<~l