ML17207A460
| ML17207A460 | |
| Person / Time | |
|---|---|
| Site: | Saint Lucie  |
| Issue date: | 10/04/1979 |
| From: | FLORIDA POWER & LIGHT CO. |
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| ML17207A459 | List: |
| References | |
| NUDOCS 7910120249 | |
| Download: ML17207A460 (18) | |
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DESIGNFEATURES5.2.1.2SHIELDBUILDINGa.C.Minimumannularspace=4feet.Annulusnominalvolume=543,000cubiceet.Nominaloutsideheight(measured
=romtopoffoundation basetothetopofthedome)=230.5eet.<<std.Nominalinsidediameer=148feet.e.Cylinderwallminimumthickness
=3feet.Domeminimumthickness
=2.5feet.Domeinsideradius=112feet.DESIGNPRESSURE.ANDTEHPERATURE 5.2.2Thecontainment vesselisdesignedandshallbemaintained foramaximuminternalpressureof44psigandatemperature
.ofZ64'F.PENETRATION55.2.3Penetrations throughthecontainment structure aredesignedandshallbemaintained inaccordance withheoriginaldesignpro-visionscontained inSections3.8.2.1.10and6.2.4oftheFSARwithallowance
=ornormaldegradation pursuanttotheapplicable Surveillance Requirements.
5.3REACTORCOREFUELASSEHBLIES 5.3.1Thereactorcoreshallcontain217fuelassemblies witheach-;uelassemblycon.aining amaximumof176fuelrodscladwithZircoloy-4.
Eachfuelrodsha':1haveanominalactivefuel1ngthof136.7inchesandcontainamaxiimumtotalweightof2250gramsuranium.Thiniialcoreloadingshallhaveamaximumenrichment of2.83weightpercentU-235.Reloadfuelshallbesimilarinphvsicaldesignto.heinitialcoreloadingandshallhavemaximumenrihmentof3.7weightpercentU-Z35.ST.LUCIE-UNIT1V9~O~S0~~~!10/4/79 SAFETYEVALUATION Re:St.LucieUnitlDocketNo.50-335FuelAssemblEnrichment Attachment A:Spent.FuelStorageRack-Criticality Evaluation SummaryAttachment B:NewFuelStorage-Criticality Evaluation SummaryAttachment C:FuelInspection
- Elevator, Upender,&FuelTransferTube-Criticality Evaluation Summary10/4/79 ATTACHMENT AFloridaPower8LightSpentFuelPoolStorageRackCriticality Evaluation SummaryI.PURPOSE8RESULTSThisreportpresentsasummaryofthecriticality evaluation ofthehighcapacity(HI-CAPT<')
fuelstoragerackdesignedtoacccnodate 728fuelassemblies infuelstoragelocations inthespentfvelpool,attheSt.LucieNuclearStation,Unit1Byvirtueoftheconservative assumptions employedinthecriticality evaluation, itisconcluded thatunder.normaloperating conditions andwithalimitingUOpfeedenrichment of3.7w/oU-235,themultiplication factorof'liefullyloadedrackinthefloodedspentfuelpooldoesnotexceedthelimitingmultiplication actorof0.95specified inA".lSI-i'(210-1976.
Thisconclusion isbasedontheresultsofanalyseswhichpredictamultiplication factorof0.947'ortherackwhenfullyloadedwithfreshfuelof.thelimitingenrichmntandimmersedinpurewaterat68oF,including allowances forcalculational uncertainties andbiases.Theseanalyseseci.ployarraysofstoragecellsthatareofinfiniteextentinboththelateralandaxialdirections, andincludetheeffectsofthemostadversecombination ofmechanical tolerances andfueldisplacement.
Increasing tnecoolanttemperature from68to225Fdecreases themultiplicationfactorby0.015.DISCUSSIOri Thisreportprovidesadescription ofthecriticality evalvation ofthehighcapacityfuelstorageracksdesignedandmanufactured byCombustion Engineering, Inc.forinstallation inthespenifuelpooloftheSt.LucielluclearStation,Unit.1.Thisrackdesignprovides728normalstoragelocations.
Eachstoragelocationisdesignedtoaccommodate onefuelassenblyconsisting of176fvelrods,and5controlrodguidetubesina14x14arraywithanominalpitchof0.580inches.Thefuelstoragelocations areoftheHI-CAPdesign>which,forthisTHapplication, consistsofatype304stainless steelboxstructure havingasquarecrosssectional geocetrywithanominalinternaldi-..ension of8.4835inches.,Theboxwallswhichcompletely enclosethefourverticalsidesofafuelassemblyhaveanominalthickness o0.250inches.Thenoninatcentertocenterspacingof12.53inchesforeachfuelstorag.box,andthenominalwatergapthickness of3.548inchesbetween.adjacentboxes,aremaintained withinspecified tolerances bystructural membersweldedtotheexteriorsurfacesoftheboxes.Subsequert sectionsofthisreportdiscussthedesignbasesandresultsofthcri.icalityevalvation.
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\'Page2A2III.DESIGNBASESA.Hulti1icationFactorThefuelstoragerackisdesignedtomeetthesubcriti~ality marginspecified inSection5.1.12.1ofANSI-<<210-1976 whichstatesinpart-"5.1.'2.1-
"Thespentfuel'storageracksshallbedesionedtoassurethatakeffnotgreaterthan0,95ismaintained withtheracksfullyloadedwithfuelandfloodedwithunborated water.--Thedesignshallbe,basedonthemaximumenrich..ent.
andfissileisotopic.
contentoY'ueltobecycledintheplant.CLB.AssumtionsEmoloedinCriticalit Evaluation Thefollowing assumptions areemployedinthecriticality evaluation toassurethattheevaluation isconservative overtherangeoffuelassemblydesignvariables providedinthespecification and/oranticipated operational conditions affecting thecriticality marginofthespentfuelpool.1.Neutronleakageeffectsaretakentobethosecharacteristic
~ofaninfinitearrayoffullyloaded,spentfuelstoracelocations inthelateraldirections andinfinitely longfuelassemblies andstorageboxwallsinthaxialdirection.
Fortheanalysesofnormalspentfuellocations employing thereerence8.4835inchI.O.'stainless steelbox,aninfinitearrayofstoragecellshavinganominalsquaredimension of12.53inchesisemployed.
Intheseanalysesitisassumedthateachfuelstoragelocationcontainsafreshfuelassemblyofthelimitingenr.ichment (3.7w/oU-235).2.Parasitic neutroncapturecontributions inthefuelstoragerackstructural materialareconsirvatively represented byneglecting allstructural materials otherthanthestainless steelboxwalls.3.Thespentfuel'poolisassu...ed tobefloodedwithpure(unborate
')wateratatemperature of68oF.Elevatedcoolanttemperature offectsareassessedby'valuating thereac:ivity changebetweenisothermal latticecalcu-lationsat68and225F.10/4/79 Page30A-34.Eachfuelassemblyisassumedtobeloadedwithunirradiated UOghavinganenrichment of3.7w/oU-235.Noburnablepoisonpins,controlrods,orneutronsourcesareassumedtobepresentinthefuelassemblies.
'.,Parasitic neutroncapturecontributions ofstructural components inthefuelassemblyareconservatively represented byneglecting thezircaloyspacersleevesandgrids.A6.The,effectoffuelstoragerackmechanical tolerances andfuelassenklg;cfisplacement withinthefuel.assemblystorageboxiscalculated inaconservative fashionbyassumingtheltd'Wadverseconcurrent combination ofdimensional tolerances andasimultanedus diagonaldisplacement ofthefuelassemblies ineachclusteroffouradjacentstoragelocations suchthateachfuelassemblyisincontactwithtwosidewallsofeachboxandthespacingbetweeneachpairofthefourfuelassemblies isminimized.
Themostadverseconcurrent combination ofdimensional tolerances corresponds toaconfiguration whereintheCol'lowing conditions existineachcellofthestoragearray:(1)mimimumpitchbetweencenterlines ofadjacentfuelstorageboxes,(2)maximumstorageboxinternaldimensions, and(3)minimumboxwallthickness.
IV.HI-CAP.PACKANALYSESAgeneraldescription ofthefuelstoragerackinthespentfuelpoolisgiveninSectionIII.Thenominaldimensions2of henormalfuelstoragelocations, definedbyCEdrawingforthefinalreference design,areasfollows:I.D.of304stainless steelbox,in.'.4835Thickness of'teelbox,.in.Materchannel,in.Center-to-center distancein.0.253.54812.5312Thephysicalparameters forthefuelassemblysuchasfuelpinradiusanddensity,cellpitch,andccmposition oiguidetubesaregiveninTableI.,Thecalculated multiplication factorforaninfinitearrayofnormal,fuelstoragelocations, eachcontaining onefuelassemblycenteredwithinth~.stainless steelbox,is0.8984.10/4/79 Page4A-4Todetermine themostadverseeffectofmechanical tolerances onthemultiplication factor,theextremesintolerances areusedratherthanastatistical model.Thefollowing tolerances andrestraints applytothenominaldimensions ofthefinalreference design:I.D.ofsteelboxattopandbottom,in.Hinimumwaterchannel,in.Boxwallthickness, in.Boxwallbow,in.Center-to-center spacingattop'ndbottomfromcornerofrack,lne+0.06252/64-0.01.and+0.047+.250+0.125Toassesstheeffectofdisplacement offuelassemblies withinthestorageboxesonthemultiplication factor,eachfuelassemblyisassumedtobedisplaced diagonally againstthecornerofitsstorageboxinadirection suchthattheclosestdistanceofapproachisachievedwithineachclusteroffourstorageboxes.Rackdimensions areassumedtobethosecorresponding totheminimumboxwallcase~examinedabove.Thecalculated multiplication factorforthiscaseis0.9324.Todetermine thereactivity at150Fand225Ffortheseanalysesallmaterials anddimensions including thecsnter-to-csnter spacingwereexpandedandthermalkernelsat150Fand225Fweree.:.ployed in,thscrosssections.
Anadditional caseatnominaldimensions at68Fwiththemorenormal1720ppmofdissolved boronpresentwasalsorun.Thelasttwocasesareusedtodetermine theworthofthsteelboxforanisolatedfloodedassembly.
Thefollowing suttmarizes theresultsofthesevencasesdiscussed above.CaseBoxC-C~SacinBoxE.D.BoxMallThickness YefeNominalCondition 68F12.4375*8,4835Nominal68F,1720ppmboron12.43758.4835Isolated, withsteelbox32.98"8.48352HinimumOffsetCondition 1'2.0000**
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-center nominalspacingisslightlysmallconstructed value.<<*Closest fuelassemblycenter-to-center spacingis11.46".0.00"0.8728erthanthe10/4/79
~Page5Thecalculational uncertainties usedinthisevaluation consistof(1)a0.0053akeffuncertainty derivedfromcomparisons ofcalculations foraseriesofVO~experirimts, (2)abiasof0.0019inoverpredicting criticality inthe~eexperiments, and(3)abiasinthecalculating steelboxwallworthinferredfromcalculations oftheJohnson-tiewlon experiments3 Themagnitude ofthelatterbiasisdeducedinthefollowing manner.Theworthofthesteelboxwallstructure whichisobtainedbysubtracting thkeffofcase6(0.8075)fromthatofcase7(0.8728)isfoundtobe0.0653akeff.Theanalysesofthe.Johnson-Newlon experimntimpliedthatfortheadditionofa0.54cmthickstainless steelshelltotheuranylfluoridesolutioncontainer, theworthofsteelwasoverestimat dbyafactorof0.0041dividedby0.0239or0.172.,Thisfactortimesthecalculated worthofsteelboxwalls(0.0653)inthestoragerackimpliesacalculational biasforthesteelof0.0112ak.Thereactivity balanceforthecriticality analysisofthenormalspentfuelstoragelocations issummarized asfollows:Hostadversecalculated Keff+95/95confidence levelcalculational uncertainty
+BiasV02(Experiment
-Calculation)
'+Stainless SteelCalculational Bias'.93240.0053-0.0019+0.01120.9470DesinConditions Hominall'.ostAdverseHultiplication FactorforSpen'tFuelStorageRackExcessHargin0.89830.037'10.94?00.003010/4/79
~~~Page6A-6-References AmricanNuclearSociety,Standards Conmittee horkingGroupANS-57.2, "DesignObjectives forLightlaterReactorSpentfuelStorageFacilities atNuclearPowerStations",
ANSI-N210-1976, approvedApril12,1976.2.CEDrawing-.=.E-3077-667-002 Rev.1,"SpentFuelRackllodule".,'ev.
l,April11,1977.3.,Clark,R.H.,etal,PhysicsVerification ProgramFinalReportBKM-3647-3(Narch1967).10/4/79 1~~~~~~IITABLE1FUELASSEftBLY PARAMETERS Fuelrodpitch.in.FuelrodarrayNumberoffuelrodsperassemblyFuelrodcladO.D.,in.FuelrodcladI.D.,in.FuelrodcladmaterialFuelpelletdiameter, incStackedfueldensity,gm/ccNumberofcontrolrod.guidetubesprassemblyGuidetubematerialGuidetubeO.D.,in.GuidetubeI.D.,in.0.5817604400.384Zircaloy-4
.0.376510.054Zircaloy-4 1.1151.035FuelAssemblyActiveFeiHeight(in.)136.710/4/79
~~~IATTACHiviEi)T 8FloridaPowerandLightNew5'uel.Storage-Criticality Evaluation Sulggary'URPOSE
&RESULTS'he purposeofthisdocumentistopresenttheresultsofacriticality evaluation madeinlg74insuppottofusingtheSt.Lucie-.lne~~i"elstoragerackf'r.fresh.
Up2fuels.with.-enrich;:eats.
upgo3.7yfgU235.Thenewfuelstorageracksconsistoftwoarraysof10x4spacesforfuelassemblies separated by'a42-inchwidespaceasshowninFigure1.Themaximumeffective neutronmultiplication factorunderconditions ofuniformwater(ofanydensity(1gm/cc)moderation inandbetweentheassemblies shouldmeettherequirements ofSection5.7.4.1ofANSN18.2whichstates:"Thedesignofspentfuelstorageracksandtransierequipment shallbesuchthattheeffective multiplication facto~willnotexceed0.95withnewfuelofthehighestanticipated enrichment inplaceassumingflooding~vithpure'water.
~Thedesignofnormaliy'dry newfuelstorageracksshallbesuchthattheeffective multiplication factorwillnotexceed0.98withfuelofthehighestanticipated enrichment inplaceassumingopiimummoderation (e.g.,auniformdensityaqueousfoamenvelopment astheresultof'irefighing).Creditmaybetakenfortheinherentneutronabs'orbing effectofr.aterials ofconstruction or,,iftherequirements ofCriterion 5.7.5.10aremet,foraddednuclearpoisons."
Typically,
.histypeo,arrayhasareactivity peakforfulldensitywateranda'econdary peakinthev.aterdensityringeof0.03to0.2gm/cc.Therack,althoughnormallydrywithakeffofabout0.70,canbeimmersedinvariouswaterdensities throuohirefighingfoams,floods,etc.Forfulldensitywaterthekeffis0.92,whichisvIellwithintherequirements ofamaximumkeffof0.95including Pnysicsuncertainties.
Thisstudyusesfour-'group transpo."t calculations forwaterdensities rangingbetwen0.02and0.075gm/ccforthe<<wfuelrack,indicatirg amaximumkefofabout0.89.10/4/79 B-2Pag2Thephysicsuncertainties aremuchlargerforthselo:~density>Iaterystemsthanforfloodedsystems,sincenoapplicable exprimentshavebeenperformer d.Thecalculated maximumkeff'soabout0.9mouldallowforanuncertainty of9.".tomeetthe0.98requirements ofAl)SN18.2.Thisisconsidered tabeadequate.
Conditions ReuiredforCriticalit SafetThcalculations performed indicatethattho.oposeddrystoragearrangements meetthecriticality safetyrequ'cerements ofNtSStandardHlS2,withamarginofabout9;linkeffforlo:Idensity<;atersideration conditions.Theproposedstoragearrangerentsare,therefore,"considered tobesafe,subjecttothfolio.~ing conditions:
l.Approvedstorageracksareused.2.3.leTheminimumsurface-to-surface spacingsbet:~eenassemblies impl":cit intheanalyses, areenforcedinthe'ackspcifi-cations(seefollowing section).
Criticality safetyWithplutonium recyclefuelhasnotbeenestablished.
Theenrichment oftheU02assemblies islimitedto3.70woU235.10/4/79 I,)~I~.8-3Page3DISCUSSTONInitsevaluation, CEhasadoptedtheapproachofassessing s'afetybasedontheminimumedge-to-edge spacingbetweenanytwoassemblies, takingintoaccountalldimensional tolerances andanticipated deformations duringearthquakes, etc.Onthisbasis,theminimumedge-to-edge spacingbetweenassemblies wouldbegreaterthan21.00-0.50(tolerance onpitch)-(815/16+1/16)=11.5inches,ratherthanthe21.00-8.2=12.8inchesimplicitintheanalyses.
Itisestimated, thatthereduction inspacingof1.3inchesduetotolerances, plusanallowance fordefor,.ation (totalspacingreduction estimated at1.5~inches)everywhere wouldincreasetliemaximumkefftoabout0.916,whichwoulddecreasethenarginforPhysicsuncertainties toabout6...However,theminimumspacinginonepositionwouldusuallyimplyalargerspacingelsewhere, andthusthekeffcouldincreasetoonly.901.Therackdesignis,there-.ore, judgedtoprovideadequatecriticality safetymarginsforconditions offogmoderation.
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~if t<TCFloridaPower8LightFuelInspection Elevator.
Upender,FuelTransferTubeCriticality Evaluation SummaryPurose8ResultsThepurposeofthisdocumentistoprovideabasisforupdatingTechSpec5.3.1forSt.Lucie1fromanenrichment of.3.1w/oto3.7w/obypresenting resultsofcriticality analysesforthefuelinspection
- elevator, theupender,andthefueltransfertube.Theapplicable standardAt<SI-H18.2 (Reference 1)section5.7.41statesinpart"Thedesignofspent-fuel storageracksandtransferequipment shallbesuchthattheeffective multi-plication factorwillnotexceed0.95withnewfuelofthehighestanticipated enrichment inplaceassumingfloodingwithpurewater,"Thehighestreactivity situation',
assumingatleastafourinchstandofftolimittheapproachofasecondassembly, is0.911,thusallowingamarginofmorethan0.03akbeyondtheallowance forcalculational.
uncertainties determined bythe.analysis ofawidevarietyofcriticalexperiments.
DesinInoutThefueldimensions anddensities forthe14x14pinasser,bly aretakenfromtheSt.Lucie1FSARusinga'3.7w/oU-235enrichment.
n,Thefuelelevatordimensions arebasedonProgrammed andRemoteSystemsCorp.Drawing-;.'-15699-0, Rev.8dated6/29/78oftheelevatorcarriage.
Standoffs appear.intheEbascodrawing8770-6841 Rev.1toatleastpartially preventasecondassemblyfromapproaching closerthanateninchedgetoedgeseparation.
Thesteelstructure viasignoredinthisanalyses.
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+~~,<a%'
1~~~e'h~~sJ.e0C-2Theupenderdimensions arebasedonP.R.S.C.DrawinqPA-13594-D Rev.0of1971fortheFuelCarrierAssemblyandindicatethattheclosest'pproach, if,twoassemblies areinthecarrierassembly, is413/16inchesandalsothepresenceoffour2x2xl/8inchstainless steelfulllengthanqlesatthecornerofeachassembly.
Thefueltransfertubeinnerradiusof35.25incheswasobtainedfromP.R.S.C.Orawinq"-'l-13~99-0, Rev.Edated7-28-76qftheFuelTranserTubeRailassemblyInstallation.
Inallcasesnon-borated.
wateratroomtemperature wasassm~edalthoughnormallyafewthousandPPl1ofdisso1ved boronarepresent.Discussion andResultsInordertomoreaccurately predictthemultiplication factoro,theassembly.
arrays,reliablecalculations oftiespatialfluxdistribuion,.esoecially intheneutronabsorbing stelregions,areessential.
Forthisreason,atwodimensional transaort calculation mod1ofthetrans-.fersystemisemployedin>>hicheachcomponent ofthefueltransfersystemqeometryisexplicitly reoresented.
Thus,inthefuelupendercalculation, thefuelassemblies, thewaterchannelbet:.'een thefuel-assemblies, thesteelangles,andthewaterreflector arereoresented asseparateregions.Thefuelassemblyitsel=isrepresented asa1'.xl4arravoffuelassemblvcellscontaining moderator andeitherfuelpinsorguidetubes.Fourneutrongroupcrosssectionsaregenera~ed
~ore.chfuelassemblycellandf'reachcomponent ofthesystemwithspecialattention qiventotheeffectofadjoining regionsonthespatialt:".rmalspectrumandhencebroadgroupthermalcrosssectionsofeachseparateregion.'Themostreactivesituation ofthethreeconsidered wouldbeforthefuelelevatorwhenasecondfuelassemblyisassumed'o bealignedwiththeoneintheelevatorwithanedgetoedqespacirgof.fourinches,i'eresultina keffis0.911.-Fortheuoenderthemostreactivesituation
.".ouldbewhenathirdasse;..blJ aooroaches towithinourinches(edgetoedqe)of'hetwoasse-blies intheupendr;thekeffforthissituation is0.899.Thiskerfislessthanforth'etwoassemblies seoarated bysamedistanceintheelevatorbcausethesteelanqlesateachcornerofbothassemblies intheupenderwereinc1udedinthean'alyses.
Thereac.ivity ofthefuelarrayinthetransertubewillbeless-..'.an-.orthecaseo<theupender,i.e.akeffof(0.8'99.
ThereasonbeingcnlJtwofuelasserblies canbeinthetransf'er tubeandtheu~lismaintained inthesaveconfiquratioo asintheupender;athirdassemblycannota"proachthetwoassemblies whileinthetransfertube.10/4/79 C-3Theabovemultiplication factorsarevalidenvelopvaluesforaminimumseparation betweenathirdassemblyfortheupenderandasecondassemblyforthefuelelevatoroffourinchesorgreater.
Reference:
l.AmericanNationalStandards Institute "NuclearSafetyCriteriafortheDesignofStationandPressurized HaterReactorPlants,"ANSI-N18.2-1973, August6,1973.10/4/79 4y.t~4<~l