ML17216A615

Proposed Tech Specs,Increasing Max Fuel Enrichment to 4.0 Weight % U-235.No Significant Hazards Evaluation Encl

ML17216A615
Person / Time
Site:	Saint Lucie
Issue date:	07/08/1986
From:	FLORIDA POWER & LIGHT CO.
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Shared Package
ML17216A614	List: ML17216A613 ML17216A615 ML17216A616
References
NUDOCS 8607150139
Download: ML17216A615 (17)

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ATTACHMENT 1PROPOSEDTIKHNICMSPECIFICATI(N DiARK8607150139 860708PDRADOCK05000335PPDR DESIGNFEATURESCONTROLELEMENTASSEMBLIES 5.3.2Thereactorcoreshallcontain73fulllengthandnopartlengthcontrolelementassemblies.

Thecontrolelementassemblies shallbedesignedandmaintained inaccordance withtheoriginaldesignprovisions contained inSection4.2.3.2of,theFSARwithallowance fornormaldegradation pursuanttotheapplicable Surveillance Requirements.

5.4REACTORCOOLANTSYSTEMDESIGNPRESSUREANDTEMPERATURE 5.4.1Thereactorcoolantsystemisdesignedandshallbemaintained:

a.Inaccordance withthecoderequirements specified inSection5.2oftheFSARwithallowance fornormaldegradation pursuanttotheapplicable Surveillance Requirements, b..Forapressureof2485psig,andc.Foratemperature of650'F.exceptforthepressurizer whichis700'F.VOLUME5.4.2Thetotalwaterandsteamvolumeofthereactorcoolantsystemis11,100+180cubicfeetataexainalTof567F.5.5EMERGENCY CORECOOLINGSYSTEMS5.5.1Theemergency corecoolingsystemsaredesignedandshallbemaintained inaccordance withtheoriginaldesignprovisions contained inSection6.3oftheFSARwithallowance fornormaldegradation pur-suanttotheapplicable Surveillance Requirements.

5.6FUELSTORAGECRITICALITY g<<(+ORg++Ti<~5g)~~gIIAgIIAIENT uelstorageracksaredesignedandshallbewithacenter-to-cen fnotcesbetweenfuelassemblies placedacs.e1storageracksaresa11bemaintained withacenter-to-center ST.LUCIE-UNIT15-5Amendment No.

OESIGNFEATURESCRITICALITY Continued n12.53inchesbetweenfuelassemblies placedinthestoraThesespaclaKfequivalent toc0.95withepoolfilledwithunborated wa.Kof<uestheconserva-tiveassumptions asdescribed intheFSAR.Inaddition, fuelinthestorageaveaU-235loaln5gramsofV-235perentimeter offuelassembly(<anenricEnent opercentU-235).DRAINAGE5.6.2Thefuelpoolisdesignedandshallbemaintained topreventinadvertent drainingofthepoolbelowelevation 56feet.CAPACITY5.6.3Thespentfuelpoolisdesignedandshallbemaintained withastoragecapacitylimitedtonomorethan728fuelassemblies.

5.7SEISMICCU5SIFICATION15.7.1Thosestructures, systemsandcomponents identified asseismicClassIinSection3.2.1oftheFSARshallbedesignedandmaintained totheoriginaldesignprovisions contained inSection3.7oftheFSARwithallowance fornormaldegradation pursuanttotheapplicable Surveillance Requirements.

5.8METEOROLOGICAL TOWERLOCATION5.8.1Theeeteorological towerlocationshallbeasshownonFigure5.1-1.5.9COMPONENT CYCLEORTRANSIENT LIMITS5.9.1Thecomponents identified inTable5.9-1aredesignedandshallbemaintained withinthecyclicortransient limitsofTable5.9-1.ST.LUCIE-UNIT15-6Amendment No.34 Ae+ee~a~~A5.6FUELSTORAGECRITICALITY 5.6.1a.Thespentfuelstorageracksaredesignedandshallbemaintained with:l.Akeffequivalent tolessthanorequalto0.95withthestoragepoolfilledwithunborated water,whichincludestheconservative assumptions asdescribed inSection9.1oftheFSAR.2.Acenter-to-center distanceofnotlessthan12.53inchesbetweenfuelassemblies placedinthestorageracks.3.Aboronconcentration greaterthanorequalto1720ppm.Inaddition, fuelinthestoragepoolshallbeaU-235enrichment oflessthanorequalto4.0weightpercent.b.Thenewfuelstorageracksaredesignedfordrystorageofunirradiated fuelassemblies havingaU-235enrichment lessthanorequalto4.0weightpercent,whilemaintaining akeffoflessthanorequalto0.98underthemostreactivecondition.

tIIIATTACHMENT 2SafetyEvaluation fora~ProaedChangetotheSt.UucieUnitlTechnical U-235.In1977arequesttoamendtheSt.Lucie,Unit1Operating Licenseforincreased spentfuelstoragewassubmitted totheNRC.ByletterdatedMarch28,1978,theCommission approvedAmendment 22totheFacilityOperating LicenseDPR-67whichallowedthemodification tothespentfuelpoolstoragefacility.

Themodificationconsistedofreracking thespentfuelpoolwith(HI-CAPTM) fuelstorageracksdesignedandmanufactured byCombustion Engineering.

Thesenewracksincreased thestoragecapacityfran310fuelassanblies to728fuelassanblies inthespentfuelpool.Thesafetyevaluation performed insupportoftherequesttoamendtheSt.LucieUnit1Operating Licensetoallowreracking ofthespentfuelpooladdressed thefollowing:

1.Structural andSeismicAnalysis2.NuclearCriticality Analysis3.ThermalHydraulic Analysis4.AccidentAnalyses5.Radiation Exposures Thecriticality analysiswasperformed fora3.7w/oU-235fuelenrichnent (linearloadingof41.45gms/anU-235).Itwasdetermined thattheproposedmodification totheUnit1spentfuelpoolwouldbeacceptable becausetheresultsoftheaboveanalysiswerewithinacceptable limits.Asaresult,theCriticality Technical Specification (5.6.1)wasupdatedtoreflectthecentertocenterspacingofthemodifiedracks(12.53inchesminimumspacing)andthemaximumallowable enrichment of41.45gramsofU-235peraxialcentimeter offuelassembly.

Arequestwasforwarded totheNRCinOctober1979toamendtheUnit1operating licenseforincreasing thefuelassemblyenrichment Technical ESpecification (5.3.1)from3.1w/oU-235toamaximumenrichment of3.7w/oU-235.Theanalysissubmitted insupportofthisIicenseamendment consisted ofperforming criticality analysesofthehighcapacityspentfuelracks,newfuelracks,fuelinspection

elevator, upenderandfueltransfertube.Theresultsofthatsafetyanalysisshowedthatwithalimitingfeedenrichment of3.7w/oU-235themultiplication factorforthevariousstructures analyzeddidnotexceedthelimitingmultiplication factorsof0.98foroptimummoderation and0.95forfullyfloodedconditions forthenewfuelstorageracksand0.95forthespentfuelracksandfuelhandlingstructures.

Itwasdecided,basedondiscussions betweenNRCandFPIstaff,thatthespecificationofreloadfuelenrichmentalonedoesnotuniquelydetermine norlimits,thevaluesofreactorcoreparameters important tosafety.Therefore, thedecisionwasmadetodeletetheenrichnent limitoffueltobeusedinthereloadcore(whichusedtobe3.1w/oU-235)from Technical Specification 5.3.1.The3.7w/oU-235enrichnent limitwasaddedtothefuelstorageTech.Spec.(5.6.1).ThisadditiontoTech.Spec.5.6.1didnotchangetheexistinglimitbutratherclarified itintermsoffuelenrichment (weightpercent).

ByletterdatedJanuary23,1980,theCaanission approvedAmendment 34totheFacilityOperating IicenseDPR-67whichdeletedthe3.7w/oU-235referenced inTech.Spec.5.3.1andaddedthe3.7weightpercentvaluetotheCriticality Technical Specification (5.6.1).Withthisapplication, FPLisrequesting approvaltoincreasethemaximumenrichment specification oftheCriticality Technical Specification (5.6.1)atSt.LucieUnit1to4.0w/oU-235(axialU-235loadingof43.91g/cm).Themotivation forthisproposedincreaseistoallowincreased flexibility infuelmanagement andtoaccommodate storageofhigherenrichments forpossibleuseinfuturecycles.Theanalysisperformed insupportofthisproposedchangecanbefoundinAppendix1.Asummaryoftheresultsofthatanalysisarediscussed inthenextsectionoftnisreport.Safe~Evaluation Theanalysisoftheproposedincreaseinfuelenrichment hasbeenaccanplished usingcurrentacceptedcodesandstandards asspecified intheSafetyAnalysisReport.Calculations performed forthehandlingandstorageof4.0w/oU-235enrichedfuelassemblies indicatethattheapplicable criticality acceptance criteriaaremet.Theevaluation wasperformed fornaturaluraniumaxialblanketfuelwithamaximumcentralfuelregionenrichment of4.0w/oU-235.Itisimportant tonotethatthenaturaluraniumaxialblanketswereneglected andhence,theanalysisisboundingforboth4.0w/oU-235enrichedfuelwithandwithoutaxialblankets.

~~Calculations performed forthespentfuelracksindicatethatunderworstcredibleconditions, theneutronmultiplication factoris0.918keffatthe95%confidence level.Thisvalueisconsiderably lowerthanthe0.95safetycriterialimitasspecified inReference 2oftheSafetyAnalysisReport.Calculations performed forthenewfuelstorageareaatvariousdegreesofmoderation (including fullflooding) indicatethatthelimitingkeffoccursforamoderator voidfractionbetween0.90and0.95andisestimated tobeabout0.925atthe95%confidence level.Thisvalueisalsoconsiderably, lowerthanthesafetycriterialimitof0.98specified inANS-N18.2.

Criticality calculations werealsoperformed forthefuelhandlingstructures.

Themostreactivesituation, i.e.theonethatproducedthehighestreactivity, involvedthefuelelevatorwhenitwasassumedthatoneassemblywasintheelevatorandoneadditional as'sembly waslocatedfour(4)inchesedgetoedgefran,theelevatorassembly.

Theresulting kefffranthisscenariois0.924atthe95%confidence level.Basedonthis,itisconcluded thatthefuelelevator, upenderandtransfertubewillaeetthesafetycriterialimitofkeff<0.95.TheNoSignificant HazardsEvaluation IofthisproposedTechnical Specification changecanbefoundinthenextsectionofthisevaluation.

References 1.R.E.Uhrig(FPf)toV.Stello(NRC)Re:St.fucieUnit1,DocketNo.50-335,ProposedAmendment toFacilityOperating l,icenseDPR-67,L-77-273,dated8/31/77.

4 2.R.E.Uhrig(FPL)toV.Stello(NRC)Re:St.LucieUnit1,DocketNo.50-335,ProposedAmerdment toFacilityOperating LicenseDPR-67,L-79-282dated10/4/79.

IEVAKlM!I@i Withthisapplication, FPLisrequesting approvaltoincreasethemaxiaaxnU-235enrichment andlinearloadingspecified inTechnical Specification (5.6.1)fromthecurrently licensed<3.7w/oU-235(axialloadingof<41.45g/cm)to<4.0w/oU-235(axialloading<43.91g/cm)atSt.LucieUnitl.Anevaluation ofthisrequesthasbeenperformed todemonstrate thatnosignificant hazardsconsideration exists,basedonacanparison withthecriteriaof10CFR50.92(C).

Thefollowing evaluation demonstrates (byreference totheanalysiscontained intheattachedSafetyAnalysisReport)thattheproposedamendment toincreasetheenrichnent specification doesnotexceedanyofthethreesignificant hazardsconsideration.

1.Therequested changedoesnotincreasetheprobability orconsequences ofaccidents previously analyzed.

Sincetheconfiguration oftheplantandthemodeofoperation remainunchanged, theprobability ofaccidents previously analyzedremainsunchanged.

FPLhasidentified thefollowing potential accidentscenarios whoseconsequences wouldbeaffectedbytheproposedchange.A.Afuelassemblydropinthespentfuelpool.B.Lossofspentfuelpoolcoolingsystemandmakeup.C.Spentfuelcaskdrop.

ForA,thecriticality acceptance criterion isnotviolatedasidentified inSection3.3oftheSafetyAnalysisReport.Theradiological consequences ofthistypeofaccidentareboundedbythefuelhandlingaccidentanalyzedintheFSARbecausethisapplication isnotintendedforextendedburnupoperation.

Inparticular, theassumptions usedintheFSARfuelhandlingaccident(i.e.burnup,fractional release,etc)arestillboundingforthehigherenrichedfuelassemblies.

Basedonthisdiscussion, itisconcluded thattheproposedamendment willnotresultinanincreaseoftheprobability orconsequences frcmthepreviously evaluated fuelhandlingaccident.

Theconsequences ofB,"lossofspentfuelcoolingsystemandmakeup"willnotbeaffectedsincethisapplication isnotintendedtoqualifythefuelforextendedburnupoperation.

TheincreaseinU-235enrichment linearloadingwillnotaffectthedecayheatcharacteristics ofthe.fuelassemblyorthepreviousFSARevaluation (Section9.1.3)ofthelossofspentfuelcoolingsystemandmakeup.Basedonthis,itisconcluded thattheproposedincreaseintheU-235enrichment linearloadingwillnotinvolveasignificant increaseintheprobability orconsequences ofanaccidentpreviously evaluated.

Theconsequences ofC,"aspentfuelcaskdrop",willnot.beaffectedbyanincreaseinlinearloadingsincethisapplication isnotintendedtoqualifythefuelforextendedburnupnoristheconfiguration ofthestorageracksbeingaltered.Therefore, theconsequences ofacaskdropaccidentarestillboundedbythepreviously evaluated FSARChapter15caskdropanalysis.

In

~~conclusion, theproposedamenchent willnotresultinanincreaseoftheprobability orconsequences ofanaccidentpreviously evaluated foracaskdrop.Basedontheabovefindings,'the proposedamendment toincreasethemaximumallowable U-235linearloadingandcorresponding enrichment doesnotresultinanincreaseintheprobability orconsequences ofanaccidentpreviously evaluated.

2.The"requested changedoesnotcreatethepossibility ofanewordifferent kindofaccidentfromanyaccidentpreviously evaluated becausetheplantconfiguration andthemannerinwhichitisoperatedremainthesame.Theproposedchangedoesnotconstitute anychangeintheprocedures forplantoperation orhardware.

Inaddition, FPjhasevaluated theproposedtechnical specification changesinaccordance withtheguidanceoftheNRCpositionpaperentitled"OTPositionforReviewandAcceptance ofSpentFuelStorageandHandlingApplications",

andappropriate IndustryCodesandStandards aslistedintheReference sectionoftheSafetyAnalysisReport.Basedonthisevaluation, FPIfindsthattheproposedtechnical specification changedoesnotcreatethepossibility ofanewordifferent kindofaccidentfrananyaccidentpreviously evaluated.

3.Theproposedchangedoesnotinvolveasignificant reduction inamarginofsafety.Asdescribed intheattachedSafetyAnalysisReport,thenewfuelstoragerackcalculated keffof0.925(95%confidence level)isconsiderably lowerthantheestablished acceptance criteriaof<0.98keff.The0.918keff(95%confidence IAI level)calculated forthespentfuelpooland0.924keff(95%confidence level)calculated forthefuelhandlingstructures isalsoconsiderably lowerthantheestablished acceptance criteriaof<0.95keff.Itisimportant tonotethattheabovecalculated neutronmultiplication factorsincludeal1thene'cessary biasesanduncertainties.

Asnotedabove,therequiredacceptance criteria(<0.98keffunderoptimummoderation conditions and<0.95underfullyfloodedconditions forthenewfuelstorageracks,<0.95keffforthespentfuelpoolandfuelhandlingstructures) havebeenadheredtointhecriticality analysisperformed insupportofthisproposedtechnical specification change.Specifically the0.02b,keffand0.05k,keff criticality marginofsafetyrequiredforthenewfuelstorageareaunderoptimummoderation andfullyfloordedconditions respectively, andthe0.05Bkeffcriticality marginofsafetyrequiredforthespentfuelstorageareaandfuelhandlingstructures havebeenmaintained asspecified intheattachedSafetyAnalysisReport.Basedonthepreviousdiscussion, theproposedanendaant toincreasethefuelstorageU-235linearloadingandcorresponding enrichment willnotinvolveasignificant reduction inthemarginofsafetyfornuclearcriticality.

Insumnary,FPThasdetermined thattheproposedtechnical specification changedoesnotinvolveasignificant hazardconsideration asdiscussed in10CFR50.92.

BasedontheattachedSafetyAnalysis, itisconcluded thatthehealthandsafetyofthepublicwillnotbeendangered bytheproposedchange.

APPENDIX1