ML17254A680

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Demonstration of Conformance of Exxon Nuclear Co Fuel to Westinghouse K(Z) Operating Envelope for Re Ginna Nuclear Power Plant.
ML17254A680
Person / Time
Site: Ginna Constellation icon.png
Issue date: 09/30/1985
From:
WESTINGHOUSE ELECTRIC COMPANY, DIV OF CBS CORP.
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Shared Package
ML17254A679 List:
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NUDOCS 8512200249
Download: ML17254A680 (13)


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DEMONSTRATIONOFTHECONFORMANCEOFEXXONNUCLEARCOMPANYFUELTOTHEWESTINGHOUSEK(Z)OPERATINGENVELOPEFORTHEROBERTE.GINNANUCLEARPOWERPLANTWestinghouseElectricCorporationNuclearTechnologyDivisionNuclearSafetyDepartmentSafeguardsEngineeringandDevelopmentSeptember19858512200249851216PDRADOCK05000244',P'DR I.ntroductionThisdocumentreportstheresultsofasensitivitystudythatwasperformedinordertodemonstrateconformanceofExxonNuclearCompanynuclearfuelintheRobertE.GinnanuclearpowerplanttotheWestinghouseK(z)operatingenvelope.Inparticular,theresultsof.thisanalysisshowthatforskewedtothetoppowershapes,inadditiontothepowershapepeakedatthemid-coreelevation,thattheworstpeakcladdingtemperature(PCT)intheunlikelyeventofaLoss-Of-Coolant-Accident(LOCA)remainsbelowthe2200deg-FlimitasspecifiedbyAppendixKof10CFR50.46.II.MethodofAnalsisThesensitivitystudywasperformedusingtheLOCTAcomputercodeoftheWestinghouse1981LargeBreakLOCAEvaluationModel(WEM)tocalculatethePCTforExxonfuelforthreepowershapes.Thepower.shapesinvestigatedIwerepeakedat6.0ft.,8.0ft.,andat10.5ft.ThepowershapesusedintheLOCAanalysesareshowninFigures1-3.ThepeakpowerofeachpowershapeislimitedbythecurrentK(z)envelopefortheRobertE.Ginna(RGE)powerplant.ThecurrentK(z)envelopeforRGEassumesamaximumtotalpeakingfactorof2.32,andahotchannelenthalpyrisefactorof1.66.

ThefueldesignparametersfortheExxonfuelwereobtainedfromtheExxonNuclearCompanythroughathree-partyproprietaryagreementbetweenWestinghouse,RochesterGas6Electric,an'dExxon.ThefuelparametersspecifictoeachpowershapeweregeneratedbyExxonandtransmittedtoWestinghouse.Thefuelparameters,whichincludedfuelpellettemperaturesandgappressures,werethenusedasinputineachoftheLOCTAcalculations.TheresultsoftheLOCTAcalculationsaresummarizedinthefollowingtable:'IComarisonofExxonFuelPeakCladdinTemeraturesPowerShapePeakPCTOFPCTElevationPCTTimesec.6~08'10'1781159815287.257'510.001065..14'TheseresultsdemonstratethatfortheRobertE.GinnaUnit,thatthechoppedcosinepowershape(i.e.6.0ft.peakedshape)generatesthemostlimitingpeakcladtemperature.Figures4-6showthecladtemperatureresponseforthepeaknodeforthe6.0,8.0,and10.5ft.powershapesrespectively.Animportantobservationoftheseresultsisthatforthetop-skewedshapes,thepeakcladdingtemperatureoccursduringtheblowdownphase.ThisisimportantbecausemostoftheAppendixKprescribedanalyticalmodelshavetheirgreatestinfluenceduringtherefloodphase.Apeak

'~cladtemperaturewhichoccursduringrefloodissensitivetocore-wideandsystem-widehydraulicphenomena,whileablowdownpeakisastrongerfunctionofinitialfuelstoredenergy.AcomparisonofthepeakcladtemperaturesduringtheblowdownandrefloodphasesforeachofthesepowershapesprovidesamoreconclusivedemonstrationthatthechoppedcosinepowershapeproducesthemostlimitingLOCAresults.ComarisonofPeakCladdinTemeraturesDurinBlowdownPowerShapePeakPCT-BlowdownopPCTElevationTimesec.6.08'10'1635159815286~007'510.005'5'4'ThecomparisonofpeakcladtemperaturesduringblowdownshowsthatthehighestPCToccursforthechoppedcosinepowershape.Thisisreasonable.,because6.0ft.shapepermitsthehighesttotallocalpeakingfactor(2.32).ThefactthatthePCTforthetop-skewedshapesoccursbelowthepeakpowerlocationisduetothebetterheattransferathigherelevationsthatoccursduringtheperiodofnegativecoreflow.

ComarisonofPeakCladdinTemeraturesDurinRefloodPowerShapePeakPCT-RefloodOFPCTElevationTimesec.6~08~010'1781158514587'5F0010.001067468Thecomparisonofrefloodpeakcladtemperaturesshowsanevenwidermarginbetweenthechoppedcosineshapeandthetop-skewedpowershapes.Znadditiontoshowingthatthechoppedcosinepowershape,isthe"worst"powershapeforaLOCAanalysisofRGEwithExxonfuel,italsodemonstratesalargemargintothe2200deg-Flimitforthetop-skewedshapesforthisplant.III.UseofNon-ExxonFuelHdraulicsThissensitivitystudywasperformedbyre-calculatingthecladVItemperatureresponseforExxonforthethreepowershapesusingtheLOCTAcomputercode.Thehotassemblyhydraulicswasnotre-calculatedfortheExxonfuel.TheblowdownandrefloodhydraulictransientsaregeneratedusingtheSATAN,WREFLOODandCOCOcomputercodes.ExistingblowdownandrefloodhydraulicsfromapreviousRGEplantspecificanalysiswithW-OFAfuelwereusedashotassemblyboundaryconditionsfortheLOCTAcalculations.UseoftheOFAhydraulicsarejustifiableforthissensitivitystudyonthefollowingbasis:

(l)TheW-OFArodsizeissmallerthantheExxonrodsize.ThiswillresultinaslowerrefloodofafullcoreofW-OFAfuel.Thus,foragivenpowershape,theuseoftheOFAcorerefloodrateprovidesaconservative'efloodratefortheExxonfuelheat-upcalculation.(2)Previoussensitivitieswithtop-skewedpowershapesinSATANhavehotshownalargeeffectontheend-of-blowdownfueltemperatures.Thus,theuseofSATANchoppedcosinepowershaperesultsfortop-skewedLOCTAcalculationscanbeconsideredsufficientlyaccurateforaroughsensitivitystudy.Becauseofthewidemarginbetweenthecosineandthetop-skewedshapePCTsinthisanalysis,re-calculationoftheSATANtransientisnotexpectedtochangetheconclusionsofthisanalysis.IV.ConclusionsTheWestinghouseLargeBreakLOCAEvaluationModelcladheat-upcomputercode,LOCTA,wasusedtoanalyzeExxonfuelforthreepowershapes.Theresultsconfirmedthatthepowershapepeaked..atthecenterofthecoreproducesthehighestpeakcladdingtemperature.ThisresultfortheExxonfuelisconsistentwithpowershapestudiesperformedbyWestinghousewiththesamecomputercodesforWestinghousefuel.TheresultsofthisstudydemonstratethattheExxonfuelintheRobertE.GinnanuclearpowerplantconformstothecurrentoperatingK(z)envelopefortop-skewedpowershapes.Whiletheentiretransientwasnotrecalculatedforthisanalysis,acompletere-analysiswouldnotbeexpectedtochangetheconclusionsofthissensitivitystudy.\

0.03.04.25,.4.755.255.75-6.256.757.257.759.012.1.S4.04.55.05.56.06.57.07.58.010.5COREHEIGHT(FEET)Figure1.AxialPowerShapePeakedat6.0ft.(ChoppedCosinePowerShape) 0.01.02.03.04.05.06.07.08.09.010.011.012.0.51.52.53.54.55.56.57.58.59.510.511.5COREHEIGHT(FEET)Figure2.AxialPowerShapePeakedat8.0ft; 2.S2.0M~1.SC51.0.5.0.01.02.03.04.05.06.07.08.09.010.011.012.0.51.52.53.54.55.56.57.58.59.510.511.5COREHEIGHT(FEET)Figure3.AxialPowerShapePeakedat10.5ft.

c~tlctl~clvbttt~ovtv[5tovlt5vttl51u0tO.~Cl(IC.C0tlte~OvltSvttlll~0~vC1[vt<<01~00IutlfiC00t'llItlJt~tot5tll~ItW>.OCC5'AO.Ovoltd.O50vAOS<lvl~55C>Figure4.CladTemperatureResponseforPCTLocationforthe6.0ft.PowerShape.

~Oll~lC~CllilCt~00lulltOOC~SwltlS'IUOt0'OCClCO,O~CaatOol~SsstlCCAOArt.lllit.wOS000~VOS'i~tCSlitl~CitySy$0tll+lVlC000.0C\SSOO.ONXol000.00.088SINSISCCIFigure5.-CladTemperatureResponseforPCTLocationfor8.0ft.PowerShape

~OltV<C,CIVVVt<<OV<Vt<VOVtV5Vatt5<VDV0,~Ott<C10.5VtvvVOvtV5vVVtC<JDAVC.1t<<V,<<0<VODOvv51~0.00<1<<Vtvv~O,DOA<~<W~0000.0o1500.0XE<Co1000.0lr0.0CII<t<5CCISg8Figure6.CladTemperatureResponseforPCTLocationforthe10.5ft.PowerShape-11