ML17221A587

Proposed Tech Specs Increasing Enrichment Spec of New Fuel Storage Rack to 4.5 Weight Percent (W/O) U-235

ML17221A587
Person / Time
Site:	Saint Lucie
Issue date:	01/20/1988
From:	FLORIDA POWER & LIGHT CO.
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ML17221A586	List: ML17221A585 ML17221A587 ML17221A588
References
NUDOCS 8801270014
Download: ML17221A587 (13)

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ATTACHMENTIMarked-upTechnicalSpecificationPageSt.LucieUnitl5-688012700148003pDRADOCN,0500@DR'P-EJW4/0I7/3 0~e.SlgShIM4gI13*~

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ATTACHMENT2SAFETYEVALUATlONEJWOIOi7/e SAFETYEVALUATIONBackroundThecurrentlylicensedfuelenrichmentlimitatSt.LucieUnitIfortheexistingnewfuelstorageracks,spentfuelracksandfuelhandlingstructuresis40w/oU235.FloridaPowerandLightCompany(FPL)hassubmittedaproposedlicenseamendmentinsupportofre-rackingtheUnitIspentfuelpoolwithhighdensitystorageracks(FPLletterL-87-245,datedJune12,1987).Thatsubmittaladdressestherequiredanalysis,i.e.,criticality,thermalhydraulic,seismic,etc.insupportofreplacingtheexistingspentfuelracks.Thecriticalityanalysisinthere-racksubmittalsupportsanenrichmentlimitof4.5w/oU-235forthehighdensityspentfuelracks.Thecriticalityanalysisfortheexistingnewfuelstorageracksandfuelhandlingequipment(AppendixI)wasperformedseparatelyfromthere-rackanalysis.Thissubmittalsupportsincreasingtheenrichmentspecificationofthenewfuelstorageracktechnicalspecification(5.6.1.b)to4.5w/O'-235.FPLisrequestingtoincreasethemaximumenrichmentspecificationofthenewfuelstoragerackCriticalityTechnicalSpecification(5.6.1..b)atSt.LucieUnitIto<4.5w/oU-235.Thisproposedchangeallowsincreasedflexi6ilityinfuelmanagementandaccommodatesstorageofhigherenrichmentsforpossibleuseinfuture'cycles.SafetEvaluationTheanalysisoftheproposedincreaseinfuelenrichmenthasbeenaccomplishedusingcurrentlyacceptedcodesandstandardsasspecifiedintheSafetyAnalysisReport.Calculationsperformedforthehandlingandstorage(newfuelracks)of4.5w/oU-235enrichedfuelassembliesdemonstratethattheapplicablecriticalityacceptancecriteriaaremet.Calculationsperformedforthenewfuelstorageracksatvariousdegreesofmoderation,includingfullflooding,indicatethatthelimitingkeffoccursforamoderatorvoidfractionof0.91andhasavalueof0.974atthe95Kconfidencelevel.Thisvalueislowerthanthesafetycriterialimitof0.98quotedintheapplicablestandardsfornewfuelstorageracksunderoptimummoderationconditions.Criticalityca1culationswerealsoperformedforthefuelhandlingstructures(fuelelevator,upenderandtransfertube)atapoolwatertemperatureof68oF.Themostreactivesituationduringnormalfuelhandlingoperationswasconservativelyassumed

'tooccurwhentwoassembliesarelocated4inchesedgetoedgefromeachother.Theresultingkefffromthisscenariois0.929atthe95Kconfidencelevel.Forpostulatedaccidentssuchashavingtwoassembliesbyaccidentachieveabundletobundlespacingoflessthan4inches,creditmaybetakenforrealisticpoolconditions.Theseconditionsincludetakingcreditforsolubleboron(>1720ppm)presentinthepoolwater.Atthisboronconcentration,thekeffisreducedbyapproximately0.20,resultinginreactivitiesfarbelowthe0.95limit.Hence,postulatedaccidentsinthefuelhandlingsystemareoflittleconcernfromacriticalitysafetystandpoint.Basedontheforegoingdiscussion,itisconcludedthatthefuelelevatorupenderandtransfertubewillmeetthesafetycriterialimitofkeff<0.95.

ATTACHMENT3DETERMINATIONOFNOSIGNIFICANTHAZARDSCONSIDERATIONThestandardsusedtoarriveatadeterminationthatarequestforamendmentinvolvesnosignificanthazardsconsiderationareincludedintheCommission'sregulations,IOCFR50.92,whichstatesthatnosignificanthazardsconsiderationsareinvolvediftheoperationofthefacilityinaccordancewiththeproposedamendmentwouldnot(I)involveasignificantincreaseintheprobabilityorconsequencesofanaccidentpreviouslyevaluated;or(2)createthepossibilityofanewordifferentkindofaccidentfromanyaccidentpreviouslyevaluated;or(3)involveasignificantreductioninamarginofsafety.Eachstandardisdiscussedasfollows:(I)Operationofthefacilityinaccordancewiththeproposedamendmentwouldnotinvolveasignificantincreaseintheprobabilityorconsequencesofanaccidentpreviouslyevaluated.FPLhasidentifiedafuelassemblydropasapotentialaccidentscenariowhoseconsequenceswouldbeaffectedbytheproposedchange.Forthistypeofaccident,thecriticalityacceptancecriterionisnotviolated.Basedontheabove,itisconcludedthattheproposedamendmentwillnotresultinanincreaseoftheprobabilityorconsequencesofaccidentspreviouslyevaluated.(2)Vseofthemodifiedspecificationwouldnotcreatethepossibilityofanewordifferentkindofaccidentfromanyaccidentpreviouslyevaluated.Therequestedchangedoesnotcreatethepossibilityofanewordifferentkindofaccidentfromanyaccidentpreviouslyevaluatedbecausetheplantconfigurationandthemannerinwhichitisoperatedremainthesame.Theproposedchangedoesnotconstituteanychangeintheproceduresforplantoperationorhardware.Inaddition,FPLhasevaluatedtheproposedtechnicalspecificationchangesinaccordancewiththeappropriateIndustryCodesandStandardsand,basedonthisevaluation,FPLfindsthattheproposedtechnicalspecif'icationchangedoesnotcreatethepossibilityofanewordifferentkindofaccidentfromanyaccidentpreviouslyevaluated.(3)Vseofthemodifiedspecificationwouldnotinvolveasignificantreductioninamarginofsafety.Theproposedchangedoesnotinvolveasignificantreductioninamarginofsafety.Thenewfuelstoragerackcalculatedkeffof0.974(95%confidencelevel)islowerthantheestablishedacceptancecriteriaof<0.98keff.The0.929keff(95%confidencelevel)calculatedforthefuelhandlingstructuresisalsoconsiderablylowerthantheestablishedacceptancecriteriaof<0.95keff.Theabovecalculatedneutronmultiplicationfactorsincludeallthenecessarybiasesanduncertainties.Asnotedabove,therequiredacceptancecriteria(<0.98keffunderoptimunmoderationconditionsand0.95underfullyfloodedconditionsforthenewfuelstorageracks,and<0.95keffforthefuelhandlingstructures)havebeenadheredtointhecriticalityanalysisperformedinsupportofthisproposedtechnicalspecificationchange.Specifically,theEJW4/0I7/5 4I4IIII'lIIIl4,4II\~FI4~II'W,tliIIII'4IgI44JrII4,~4II'I4~IIlII4FW~\'I4IIgtkll4'.FhI,IWIhIt4~l.I~IF44444,I4hlhtt,r4~~1444'4I'IIIIIII44IFW4I41IIWIII)'4I,4I~I~I4IW41Nh'WI4'I~I4I4'III~IWII~'uI'4'~4IIhflI411444I4'Im1'll-'.I*I 0.02keffand0.05keffcriticalitymarginofsafetyrequiredforthenewfuelstorageareaunderoptimummoderationandfullyfloodedconditionsrespectively,and0.05keffcriticalitymarginofsafetyrequiredforthefuelhandlingstructureshavebeenmaintained.Basedonthepreviousdiscussion,theproposedamendmenttoincreasetheallowablefuelU-235enrichmentinthenewfuelstorageracksandfuelhandlingequipmentwillnotinvolveasignificantreductioninamarginofsafety.Basedontheabove,'wehavedeterminedthattheamendmentrequestdoesnot(l)involveasignificantincreaseintheprobabilityorconsequencesofanaccidentpreviouslyevaluated,(2)createtheprobabilityofanewordifferentkindofaccidentfromanyaccidentpreviouslyevaluated,or(3)involveasignificantreductioninamarginofsafety;andthereforedoesnotinvolveasignificanthazardsconsideration.EJWO/0I7/6 0p=<<I<<4i,<<l,<<UIII-<<~I4fl4>>I,,II4fIi~ffIfU<<ILI4~.4I4<<I<<~il~<<.4<<~4"~~'I.I,4,~<<44U'if4444Ul~4II<<4<<<<~4il<<4<<"<<<<~ikll4L.~~3<<-<<<<

APPENOIX1 1/Iy~f