ML17249A717: Difference between revisions

From kanterella
Jump to navigation Jump to search
(Created page by program invented by StriderTol)
(Created page by program invented by StriderTol)
Line 17: Line 17:


=Text=
=Text=
{{#Wiki_filter:NtestinghouseElectricCorporationYYaterReactorDivisionsiix&rTechnologyOivisionBox355PitlsburghPennsylvania15230February5,1980NS-RAW-005Mr.DennisZiemann,ChiefOperatingReactorBranchS2DivisionofOperatingReactorsOfficeofNuclearReactorRegulationU.S.NuclearRegulatoryCommissionWashington,0.C.20555
{{#Wiki_filter:Ntestinghouse ElectricCorporation YYaterReactorDivisions iix&rTechnology OivisionBox355PitlsburghPennsylvania 15230February5,1980NS-RAW-005 Mr.DennisZiemann,ChiefOperating ReactorBranchS2DivisionofOperating ReactorsOfficeofNuclearReactorRegulation U.S.NuclearRegulatory Commission Washington, 0.C.20555


==SUBJECT:==
==SUBJECT:==
DocketNo.50-244,R.E.GinnaNuclearPowerPlantREF:RochesterGasandElectricCompanyApplicationforWithholding,WhitetoZiemann,February1980
DocketNo.50-244,R.E.GinnaNuclearPowerPlantREF:Rochester GasandElectricCompanyApplication forWithholding, WhitetoZiemann,February1980


==DearHr.Ziemann:==
==DearHr.Ziemann:==
TheproprietarymaterialforwhichwithholdingisbeingrequestedbyRochesterGasandElectricCompany(RGE)isofthesametechnicaltypeasthatproprietarymaterialpreviouslysubmittedinconnectionwithanNRC.Staffreloadreview.Thepreviousapplicationforwithholding,AH-76-31,wasaccompaniedbyanon-proprietaryaffidavitsignedbytheowneroftheproprietaryinformation,Westinghouse'ElectricCorporation.Thesubject.proprietarymaterialisbeingsubmittedinsupportofthereloadreviewmsociatedwithRGE'sR.E.GinnaNuclearPowerPlant,Cycle10.OnMarch2,1977,Westinghousesubmittedaproprietaryaffidavittosupple-mentthenon-proprietaryaffidavitaccompanyingapplicationforwithholdingAW-76-31.BecausethereloadreviewmaterialassociatedwithCycle10isofthesametechnicaltypeasthatassociatedwithWCAP-9272,theproprietaryaffidavitsubmittedtosupplementthepreviousjustificationisequallyapplicabletothismaterial.Accordingly,thisletterauthorizestheutilizationofthepreviouslyfur-nishedaffidavitsinsupportofthereloadreviewassociatedwithRGE'.sR.E.GinnaNuclearPowerPlant,Cycle10.  
Theproprietary materialforwhichwithholding isbeingrequested byRochester GasandElectricCompany(RGE)isofthesametechnical typeasthatproprietary materialpreviously submitted inconnection withanNRC.Staffreloadreview.Thepreviousapplication forwithholding, AH-76-31, wasaccompanied byanon-proprietary affidavit signedbytheowneroftheproprietary information, Westinghouse
~P;Mr.D.Ziemann0PwFebruary5,1980NS-RAW-005Correspondencewithrespecttotheproprietaryaspectsoftheapp1ica-tionforwithho1dingortheWestinghouseaffidavitsshou1dreferenceCAW-80-08,andshouldbeaddressedtotheundersigned.Very'tru1yyours,~>&6M.a.KJRobertA.Hiesemann,ManagerRegulatoryELegislativeAffairs/bek.cc:J.A.Cooke,Esq.(NRC)L.D.White(RGE)
'Electric Corporation.
AttachmentBResponsetoQuestion6onMixedOxideFuel(Proprietary)  
Thesubject.proprietary materialisbeingsubmitted insupportofthereloadreviewmsociated withRGE'sR.E.GinnaNuclearPowerPlant,Cycle10.OnMarch2,1977,Westinghouse submitted aproprietary affidavit tosupple-mentthenon-proprietary affidavit accompanying application forwithholding AW-76-31.
Becausethereloadreviewmaterialassociated withCycle10isofthesametechnical typeasthatassociated withWCAP-9272, theproprietary affidavit submitted tosupplement thepreviousjustification isequallyapplicable tothismaterial.
Accordingly, thisletterauthorizes theutilization ofthepreviously fur-nishedaffidavits insupportofthereloadreviewassociated withRGE'.sR.E.GinnaNuclearPowerPlant,Cycle10.  
~P;Mr.D.Ziemann0PwFebruary5,1980NS-RAW-005 Correspondence withrespecttotheproprietary aspectsoftheapp1ica-tionforwithho1ding ortheWestinghouse affidavits shou1dreference CAW-80-08, andshouldbeaddressed totheundersigned.Very'tru1y yours,~>&6M.a.KJ RobertA.Hiesemann, ManagerRegulatory ELegislative Affairs/bek.cc:J.A.Cooke,Esq.(NRC)L.D.White(RGE)
Attachment BResponsetoQuestion6onMixedOxideFuel(Proprietary)  
~.  
~.  
~g41WESTINGHOUSEPROPRIETARYCLASS26.ThestaffSERonMixedOxideFuelstatesthatuseofU02densificationmodelsforHOXshouldbeverified.(l)SinceitappearsthatthisassumptionwasusedfortheVOXfuelforGinna,pleaseverifythisassumption.DoesthepredictedamountofdensificationsatisfyReg.Guide1.126.ThecurrentWestinghouseU02fueldensificationmodelwasusedtopredictthedensificationperformanceofthetIOxfuelsfabricatedforGinna.Thisempiricalmodel,whichwasderivedusingonlyU02performancedata,usesfuelsinteringtemperatureandsintereddensitytopredicttheextentofdensification.-TheapplicationofthemodeltolIOfuelisjustifiedonXtwobases;thesimilarityinprocedureusedinfabricationofNOfueltoXUO>proceduresandtheabilitytoconservativelypredicttheperformanceofpreviouslyirradiatedt~i0fuels.XWhile,studyingthedensificationofpureU02,therelativedimensional,stabilityoffuelwasfoundtobestronglydependentonthepelletizing.processemployedandthevaluesofkeyprocessingparameters.TheprocessesusedinpelletfabricationforGinnaareessentiallyidenticalv(iththoseused.inpreparingMOfuelpreviouslyirradiatedbyWestinghousewhoseXperformanceisconservativelypredictedbytheU02model.Further,thepelletizingprocessesusedforpreparingtheGinnaIl0fuelisverysimilarXtothatusedbyWestinghousetoproduceU02fuel.Thelimitingprocessing''parameters,sinteringtemperatureandfinalpelletdensity,werecontrolledtoarangewhichproducesU02fuelwithpredictedperformancewithindesignrequirements.TheWestinghouseexperiencewithIIOdensificationperformanceduringirradiationhasbeenreportedandcomparedwithmodelpredictionsinWCAP-8349-P.Theoretically,MOdensificationwouldbeexpectedtoXproceedatalowerratethaninUOsinceporeremovalisdirectlyrelatedtolocalfissionevents.Densificationorporeremovalisabu1kprocessandinU02fuelthefissioneventsarefairlyuniformlydistributedinthematerialandtheproductdensifiesuniformly..However,inMOthefissioneventsareconcentratedinorveryneartoPu02particleswhicharefreetodensifyindependentlyoftheU02matrix.ThelowenrichmentU02matrixexperiencesalowerfrequencyoTfissioneventsthannormalenrichedU02fuelatsimilarburnupandshouldshowaloweramountofdensification.TheWestinghouse urSTINGHOUSEPROPRIETARYCLASS2'2experiencewithdensificationofMOfueloperatedinacorrmercialpowerXreactoriscomparedwithpredictedvaluesinFigure1whichistaken'fromMCAP-8349-P.TheFigurealsocontainsdatafortheperformanceofaVO2fuelwithsimilarfabricationcharacteristicsfordirectcomparison.Figure1containsdataforbothmechanicallymixedand"mastermixed"fuel.Mastermixedfuelispreparedbyco-precipitatingV02and'Pu02thenmixingtheCo-precipitatedmaterialwithU02.TheU02modelisabestestimatemodelandhencethereshouldbe'asmanypointswithdensificationunderpredictedasoverpredicted.ThisisobviouslynotthecaseforeithertheU02orMOfuelwiththedensification'beinggenerallyoverpredicted.Significantly,thepredictionofthemodelwasnoticeablymoreconservativefortheMOfuelthanfortheU02withXsimilarprocessinghistory.AsshowninFigure1,thepredictionformastermixedMOwaslessconservativethanfor'mchanicallymixedMO.ThisisasXX~expectedandfurtherillustratesthelowerdensificationexpectedfromfuel'withinhomogenouslydistributedfissionevents.TheperformanceofanMOfuelofhigherPu02contentwhichwasoperatedinXtheSaxtontestreactorwasalsoreportedinMCAP-8349-P.'hisfuel,which.operatedathighertemperaturesthancommercialpowerreactors,'asalsofoundtodensifylessthanpredictedbythemodel.ThepredictivecapabilityoftheU02modelwasfurthertestedbyevaluatingtheperformanceoftheMOfuelintheEPRIMO.densificationprogram.'heseXXfuelswerepreparedbyawidevariationinprocessingvariablesandhencerepresentarangeofconditionsgreaterthanwaspresentindataonwhichthemodelwasbased.TheperformanceoftheEPRIfuelsasreportedinEPRIHP-637arecomparedwithmodelpredictionsinFigure2.ThedatainFigure2indicatethemodelisessentiallyconservativeforallfuelsshown,eventhoseunstablefuelspreparedbyproceduresdissimilartothoseforfuelonwhoseperformancethemodelisbased.Forthestablefuels,thosewhichdensified<2volumepercent,themodelishighlyconservativeinthatitgreatlyoverpredictsthedensification.TheGinnaMOfuelisprojectedtobehavestably;allcurrentlymanufacturedWestinghouseU02fuelsarealsoprojectedtoshow'stablebehavior.  
~g41WESTINGHOUSE PROPRIETARY CLASS26.ThestaffSERonMixedOxideFuelstatesthatuseofU02densification modelsforHOXshouldbeverified.(l)
)YESTlNG'HOUSEPRPPRIU~QYgQSSPsReg.Guide1.126doesnotindicateamaximumamountofdensificationallowablebut,ratherdefinestheamountofdensificationthatmustbeassumedbasedona'thermalresinteringtest.Designmustaccountfortheamountofdensificationassumedfromtheresintertest.ThermalresinterdataisnotavailablefortheGinnat10fuelsoanalternateXmethodmustbechosentopredictthedensificationperformance;the'ethodusedwastheWestinghouseU02model.TheaccuracyofthismodelcanbecomparedtothepredictionsfromthethermalresintermodelinReg.Guide1.126.ThebasisforestablishingtherelativeabilitiesofthetwomodelstopredictperformancewasestablishedbyuseoftheEPRIdata.The.predictedperformanceusingthethermalresinteringmodeliscomparedwithactualperformanceinFigure3.ExaminationofdatainFigure3indicatestheresintermodelsignificantlyoverpredictstheamountofdensification,especiallyinthe.regionofstablefuels(<2-v6lumepercentdensification)wheretheoverpredictionisasmuchas2.5percent.ComparisonofFigures2'Cand3indicatestherelativepredictiveabilities'ofthetwomodels.Thecomparisonshowsthetwomodelsareverysimilar,bothmodelsbeinggenerallyconservative.Thedegreeofconservatismisfoundtobegreaterintheregionofstablefuels.Similarnumbersofdatapointsareslightlyunder-predictedbythetwomodels,however,theWestinghousemodelisbothmoreconsistentandmoreconservativeinthelessthan2percentdensification'angewhichisrepresentativeoftheGinnaHOfuel.XThedatapresenteddemonstratethattheWestinghouseU02fuel,densificationmodelyieldspredictionssimilarto'ndmorereliablyconservativeforNOXfuelthantheresintermodelinReg.Guide1.126.'
Sinceitappearsthatthisassumption wasusedfortheVOXfuelforGinna,pleaseverifythisassumption.
STIIIGHOUSEPROPRIETARYCLASSII8198-I9).b,c)~E'1.0OIC3LEGEHO'HIXEOU02-3j,PuO~HASTERAIXEOUO2<<3$Pu02QUO>.0.00.0,0.5'.0MEASUREDSTACKLEHGTHDECREASE,nL/LOR1/3Ap/p(PRESENT)Figure1.ComparisonoFDensificationDataforUO-3%PuOwithUOBothFabricatedunderSimilarConditionstoaDensityofApproximately91%T.D.  
Doesthepredicted amountofdensification satisfyReg.Guide1.126.ThecurrentWestinghouse U02fueldensification modelwasusedtopredictthedensification performance ofthetIOxfuelsfabricated forGinna.Thisempirical model,whichwasderivedusingonlyU02performance data,usesfuelsintering temperature andsintereddensitytopredicttheextentofdensification.-
Theapplication ofthemodeltolIOfuelisjustified onXtwobases;thesimilarity inprocedure usedinfabrication ofNOfueltoXUO>procedures andtheabilitytoconservatively predicttheperformance ofpreviously irradiated t~i0fuels.XWhile,studyingthedensification ofpureU02,therelativedimensional
,stability offuelwasfoundtobestronglydependent onthepelletizing
.processemployedandthevaluesofkeyprocessing parameters.
Theprocesses usedinpelletfabrication forGinnaareessentially identical v(iththoseused.inpreparing MOfuelpreviously irradiated byWestinghouse whoseXperformance isconservatively predicted bytheU02model.Further,thepelletizing processes usedforpreparing theGinnaIl0fuelisverysimilarXtothatusedbyWestinghouse toproduceU02fuel.Thelimitingprocessing
''parameters, sintering temperature andfinalpelletdensity,werecontrolled toarangewhichproducesU02fuelwithpredicted performance withindesignrequirements.
TheWestinghouse experience withIIOdensification performance duringirradiation hasbeenreportedandcomparedwithmodelpredictions inWCAP-8349-P.
Theoretically, MOdensification wouldbeexpectedtoXproceedatalowerratethaninUOsinceporeremovalisdirectlyrelatedtolocalfissionevents.Densification orporeremovalisabu1kprocessandinU02fuelthefissioneventsarefairlyuniformly distributed inthematerialandtheproductdensifies uniformly.
.However,inMOthefissioneventsareconcentrated inorveryneartoPu02particles whicharefreetodensifyindependently oftheU02matrix.Thelowenrichment U02matrixexperiences alowerfrequency oTfissioneventsthannormalenrichedU02fuelatsimilarburnupandshouldshowaloweramountofdensification.
TheWestinghouse urSTINGHOUSE PROPRIETARY CLASS2'2experience withdensification ofMOfueloperatedinacorrmercial powerXreactoriscomparedwithpredicted valuesinFigure1whichistaken'fromMCAP-8349-P.
TheFigurealsocontainsdatafortheperformance ofaVO2fuelwithsimilarfabrication characteristics fordirectcomparison.
Figure1containsdataforbothmechanically mixedand"mastermixed" fuel.Mastermixed fuelispreparedbyco-precipitating V02and'Pu02thenmixingtheCo-precipitated materialwithU02.TheU02modelisabestestimatemodelandhencethereshouldbe'asmanypointswithdensification underpredicted asoverpredicted.
Thisisobviously notthecaseforeithertheU02orMOfuelwiththedensification' beinggenerally overpredicted.
Significantly, theprediction ofthemodelwasnoticeably moreconservative fortheMOfuelthanfortheU02withXsimilarprocessing history.AsshowninFigure1,theprediction formastermixedMOwaslessconservative thanfor'mchanically mixedMO.ThisisasXX~expectedandfurtherillustrates thelowerdensification expectedfromfuel'withinhomogenously distributed fissionevents.Theperformance ofanMOfuelofhigherPu02contentwhichwasoperatedinXtheSaxtontestreactorwasalsoreportedinMCAP-8349-P
.'hisfuel,which.operated athighertemperatures thancommercial powerreactors,'as alsofoundtodensifylessthanpredicted bythemodel.Thepredictive capability oftheU02modelwasfurthertestedbyevaluating theperformance oftheMOfuelintheEPRIMO.densification program.'heseXXfuelswerepreparedbyawidevariation inprocessing variables andhencerepresent arangeofconditions greaterthanwaspresentindataonwhichthemodelwasbased.Theperformance oftheEPRIfuelsasreportedinEPRIHP-637arecomparedwithmodelpredictions inFigure2.ThedatainFigure2indicatethemodelisessentially conservative forallfuelsshown,eventhoseunstablefuelspreparedbyprocedures dissimilar tothoseforfuelonwhoseperformance themodelisbased.Forthestablefuels,thosewhichdensified
<2volumepercent,themodelishighlyconservative inthatitgreatlyoverpredicts thedensification.
TheGinnaMOfuelisprojected tobehavestably;allcurrently manufactured Westinghouse U02fuelsarealsoprojected toshow'stablebehavior.  
)YESTlNG'HOUSE PRPPRIU~QYgQSSPsReg.Guide1.126doesnotindicateamaximumamountofdensification allowable but,ratherdefinestheamountofdensification thatmustbeassumedbasedona'thermalresintering test.Designmustaccountfortheamountofdensification assumedfromtheresintertest.Thermalresinterdataisnotavailable fortheGinnat10fuelsoanalternate Xmethodmustbechosentopredictthedensification performance; the'ethodusedwastheWestinghouse U02model.Theaccuracyofthismodelcanbecomparedtothepredictions fromthethermalresintermodelinReg.Guide1.126.Thebasisforestablishing therelativeabilities ofthetwomodelstopredictperformance wasestablished byuseoftheEPRIdata.The.predicted performance usingthethermalresintering modeliscomparedwithactualperformance inFigure3.Examination ofdatainFigure3indicates theresintermodelsignificantly overpredicts theamountofdensification, especially inthe.regionofstablefuels(<2-v6lumepercentdensification) wheretheoverprediction isasmuchas2.5percent.Comparison ofFigures2'Cand3indicates therelativepredictive abilities
'ofthetwomodels.Thecomparison showsthetwomodelsareverysimilar,bothmodelsbeinggenerally conservative.
Thedegreeofconservatism isfoundtobegreaterintheregionofstablefuels.Similarnumbersofdatapointsareslightlyunder-predicted bythetwomodels,however,theWestinghouse modelisbothmoreconsistent andmoreconservative inthelessthan2percentdensification
'angewhichisrepresentative oftheGinnaHOfuel.XThedatapresented demonstrate thattheWestinghouse U02fuel,densification modelyieldspredictions similarto'ndmorereliablyconservative forNOXfuelthantheresintermodelinReg.Guide1.126.'
STIIIGHOUSE PROPRIETARY CLASSII8198-I9).b,c)~E'1.0OIC3LEGEHO'HIXEOU02-3j,PuO~HASTERAIXEO UO2<<3$Pu02QUO>.0.00.0,0.5'.0MEASUREDSTACKLEHGTHDECREASE, nL/LOR1/3Ap/p(PRESENT)
Figure1.Comparison oFDensification DataforUO-3%PuOwithUOBothFabricated underSimilarConditions toaDensityofApproximately 91%T.D.  


)VESTIWGHOUSEPROPRIETARYCI.aSS2Figure2.WestinghouseU02ModelPredictionofDensificationofEPRIMOFuelsXQzz0>>Qi>QlgQ.Q>>Qp,QQ<<oEU10Qiz@<aO~'gQIIpgrsQ<<~i;Q3<<7(DllQaQ<<QvQMOMechanicallyMixedSMOMasterMixedQU02DataNumbersindicateEPRI'fueltypes.023ActualChangeinDensity,5  
)VESTIWGHOUSE PROPRIETARY CI.aSS2Figure2.Westinghouse U02ModelPrediction ofDensification ofEPRIMOFuelsXQzz0>>Qi>QlgQ.Q>>Qp,QQ<<oEU10Qiz@<aO~'gQIIpgrsQ<<~i;Q3<<7(DllQaQ<<QvQMOMechanically MixedSMOMasterMixedQU02DataNumbersindicateEPRI'fueltypes.023ActualChangeinDensity,5  


WESTINGHOUSEPROPRIETARYCUSS2Figure3.Reg.GuidePredictionofEPRIMODataXl9)9QIQfwGQcJ32.CLOl~l3Of8~gggg0>~OI~gyOl8'bs\l7(7(ptgIXlkQ0IkOMOMechanicallyMixedXIMOxMastert1ixedeU02DataNumbersindicateEPRIfueltypes.~1"02'ActualChangeinDensity}}
WESTINGHOUSE PROPRIETARY CUSS2Figure3.Reg.GuidePrediction ofEPRIMODataXl9)9QIQfwGQcJ32.CLOl~l3Of8~gggg0>~OI~gyOl8'bs\l7(7(ptgIXlkQ0IkOMOMechanically MixedXIMOxMastert1ixedeU02DataNumbersindicateEPRIfueltypes.~1"02'ActualChangeinDensity}}

Revision as of 14:54, 29 June 2018

Advises of Authorization to Use Previously Furnished Affidavits for Current Reload Review Re Cycle 10. Same Proprietary Matl Being Used
ML17249A717
Person / Time
Site: Ginna Constellation icon.png
Issue date: 02/05/1980
From: WIESEMANN R A
WESTINGHOUSE ELECTRIC COMPANY, DIV OF CBS CORP.
To: ZIEMANN D L
Office of Nuclear Reactor Regulation
Shared Package
ML17249A716 List:
References
NS-RAW-005, NS-RAW-5, NUDOCS 8002250527
Download: ML17249A717 (12)


Text

Ntestinghouse ElectricCorporation YYaterReactorDivisions iix&rTechnology OivisionBox355PitlsburghPennsylvania 15230February5,1980NS-RAW-005 Mr.DennisZiemann,ChiefOperating ReactorBranchS2DivisionofOperating ReactorsOfficeofNuclearReactorRegulation U.S.NuclearRegulatory Commission Washington, 0.C.20555

SUBJECT:

DocketNo.50-244,R.E.GinnaNuclearPowerPlantREF:Rochester GasandElectricCompanyApplication forWithholding, WhitetoZiemann,February1980

DearHr.Ziemann:

Theproprietary materialforwhichwithholding isbeingrequested byRochester GasandElectricCompany(RGE)isofthesametechnical typeasthatproprietary materialpreviously submitted inconnection withanNRC.Staffreloadreview.Thepreviousapplication forwithholding, AH-76-31, wasaccompanied byanon-proprietary affidavit signedbytheowneroftheproprietary information, Westinghouse

'Electric Corporation.

Thesubject.proprietary materialisbeingsubmitted insupportofthereloadreviewmsociated withRGE'sR.E.GinnaNuclearPowerPlant,Cycle10.OnMarch2,1977,Westinghouse submitted aproprietary affidavit tosupple-mentthenon-proprietary affidavit accompanying application forwithholding AW-76-31.

Becausethereloadreviewmaterialassociated withCycle10isofthesametechnical typeasthatassociated withWCAP-9272, theproprietary affidavit submitted tosupplement thepreviousjustification isequallyapplicable tothismaterial.

Accordingly, thisletterauthorizes theutilization ofthepreviously fur-nishedaffidavits insupportofthereloadreviewassociated withRGE'.sR.E.GinnaNuclearPowerPlant,Cycle10.

~P;Mr.D.Ziemann0PwFebruary5,1980NS-RAW-005 Correspondence withrespecttotheproprietary aspectsoftheapp1ica-tionforwithho1ding ortheWestinghouse affidavits shou1dreference CAW-80-08, andshouldbeaddressed totheundersigned.Very'tru1y yours,~>&6M.a.KJ RobertA.Hiesemann, ManagerRegulatory ELegislative Affairs/bek.cc:J.A.Cooke,Esq.(NRC)L.D.White(RGE)

Attachment BResponsetoQuestion6onMixedOxideFuel(Proprietary)

~.

~g41WESTINGHOUSE PROPRIETARY CLASS26.ThestaffSERonMixedOxideFuelstatesthatuseofU02densification modelsforHOXshouldbeverified.(l)

Sinceitappearsthatthisassumption wasusedfortheVOXfuelforGinna,pleaseverifythisassumption.

Doesthepredicted amountofdensification satisfyReg.Guide1.126.ThecurrentWestinghouse U02fueldensification modelwasusedtopredictthedensification performance ofthetIOxfuelsfabricated forGinna.Thisempirical model,whichwasderivedusingonlyU02performance data,usesfuelsintering temperature andsintereddensitytopredicttheextentofdensification.-

Theapplication ofthemodeltolIOfuelisjustified onXtwobases;thesimilarity inprocedure usedinfabrication ofNOfueltoXUO>procedures andtheabilitytoconservatively predicttheperformance ofpreviously irradiated t~i0fuels.XWhile,studyingthedensification ofpureU02,therelativedimensional

,stability offuelwasfoundtobestronglydependent onthepelletizing

.processemployedandthevaluesofkeyprocessing parameters.

Theprocesses usedinpelletfabrication forGinnaareessentially identical v(iththoseused.inpreparing MOfuelpreviously irradiated byWestinghouse whoseXperformance isconservatively predicted bytheU02model.Further,thepelletizing processes usedforpreparing theGinnaIl0fuelisverysimilarXtothatusedbyWestinghouse toproduceU02fuel.Thelimitingprocessing

parameters, sintering temperature andfinalpelletdensity,werecontrolled toarangewhichproducesU02fuelwithpredicted performance withindesignrequirements.

TheWestinghouse experience withIIOdensification performance duringirradiation hasbeenreportedandcomparedwithmodelpredictions inWCAP-8349-P.

Theoretically, MOdensification wouldbeexpectedtoXproceedatalowerratethaninUOsinceporeremovalisdirectlyrelatedtolocalfissionevents.Densification orporeremovalisabu1kprocessandinU02fuelthefissioneventsarefairlyuniformly distributed inthematerialandtheproductdensifies uniformly.

.However,inMOthefissioneventsareconcentrated inorveryneartoPu02particles whicharefreetodensifyindependently oftheU02matrix.Thelowenrichment U02matrixexperiences alowerfrequency oTfissioneventsthannormalenrichedU02fuelatsimilarburnupandshouldshowaloweramountofdensification.

TheWestinghouse urSTINGHOUSE PROPRIETARY CLASS2'2experience withdensification ofMOfueloperatedinacorrmercial powerXreactoriscomparedwithpredicted valuesinFigure1whichistaken'fromMCAP-8349-P.

TheFigurealsocontainsdatafortheperformance ofaVO2fuelwithsimilarfabrication characteristics fordirectcomparison.

Figure1containsdataforbothmechanically mixedand"mastermixed" fuel.Mastermixed fuelispreparedbyco-precipitating V02and'Pu02thenmixingtheCo-precipitated materialwithU02.TheU02modelisabestestimatemodelandhencethereshouldbe'asmanypointswithdensification underpredicted asoverpredicted.

Thisisobviously notthecaseforeithertheU02orMOfuelwiththedensification' beinggenerally overpredicted.

Significantly, theprediction ofthemodelwasnoticeably moreconservative fortheMOfuelthanfortheU02withXsimilarprocessing history.AsshowninFigure1,theprediction formastermixedMOwaslessconservative thanfor'mchanically mixedMO.ThisisasXX~expectedandfurtherillustrates thelowerdensification expectedfromfuel'withinhomogenously distributed fissionevents.Theperformance ofanMOfuelofhigherPu02contentwhichwasoperatedinXtheSaxtontestreactorwasalsoreportedinMCAP-8349-P

.'hisfuel,which.operated athighertemperatures thancommercial powerreactors,'as alsofoundtodensifylessthanpredicted bythemodel.Thepredictive capability oftheU02modelwasfurthertestedbyevaluating theperformance oftheMOfuelintheEPRIMO.densification program.'heseXXfuelswerepreparedbyawidevariation inprocessing variables andhencerepresent arangeofconditions greaterthanwaspresentindataonwhichthemodelwasbased.Theperformance oftheEPRIfuelsasreportedinEPRIHP-637arecomparedwithmodelpredictions inFigure2.ThedatainFigure2indicatethemodelisessentially conservative forallfuelsshown,eventhoseunstablefuelspreparedbyprocedures dissimilar tothoseforfuelonwhoseperformance themodelisbased.Forthestablefuels,thosewhichdensified

<2volumepercent,themodelishighlyconservative inthatitgreatlyoverpredicts thedensification.

TheGinnaMOfuelisprojected tobehavestably;allcurrently manufactured Westinghouse U02fuelsarealsoprojected toshow'stablebehavior.

)YESTlNG'HOUSE PRPPRIU~QYgQSSPsReg.Guide1.126doesnotindicateamaximumamountofdensification allowable but,ratherdefinestheamountofdensification thatmustbeassumedbasedona'thermalresintering test.Designmustaccountfortheamountofdensification assumedfromtheresintertest.Thermalresinterdataisnotavailable fortheGinnat10fuelsoanalternate Xmethodmustbechosentopredictthedensification performance; the'ethodusedwastheWestinghouse U02model.Theaccuracyofthismodelcanbecomparedtothepredictions fromthethermalresintermodelinReg.Guide1.126.Thebasisforestablishing therelativeabilities ofthetwomodelstopredictperformance wasestablished byuseoftheEPRIdata.The.predicted performance usingthethermalresintering modeliscomparedwithactualperformance inFigure3.Examination ofdatainFigure3indicates theresintermodelsignificantly overpredicts theamountofdensification, especially inthe.regionofstablefuels(<2-v6lumepercentdensification) wheretheoverprediction isasmuchas2.5percent.Comparison ofFigures2'Cand3indicates therelativepredictive abilities

'ofthetwomodels.Thecomparison showsthetwomodelsareverysimilar,bothmodelsbeinggenerally conservative.

Thedegreeofconservatism isfoundtobegreaterintheregionofstablefuels.Similarnumbersofdatapointsareslightlyunder-predicted bythetwomodels,however,theWestinghouse modelisbothmoreconsistent andmoreconservative inthelessthan2percentdensification

'angewhichisrepresentative oftheGinnaHOfuel.XThedatapresented demonstrate thattheWestinghouse U02fuel,densification modelyieldspredictions similarto'ndmorereliablyconservative forNOXfuelthantheresintermodelinReg.Guide1.126.'

STIIIGHOUSE PROPRIETARY CLASSII8198-I9).b,c)~E'1.0OIC3LEGEHO'HIXEOU02-3j,PuO~HASTERAIXEO UO2<<3$Pu02QUO>.0.00.0,0.5'.0MEASUREDSTACKLEHGTHDECREASE, nL/LOR1/3Ap/p(PRESENT)

Figure1.Comparison oFDensification DataforUO-3%PuOwithUOBothFabricated underSimilarConditions toaDensityofApproximately 91%T.D.

)VESTIWGHOUSE PROPRIETARY CI.aSS2Figure2.Westinghouse U02ModelPrediction ofDensification ofEPRIMOFuelsXQzz0>>Qi>QlgQ.Q>>Qp,QQ<<oEU10Qiz@<aO~'gQIIpgrsQ<<~i;Q3<<7(DllQaQ<<QvQMOMechanically MixedSMOMasterMixedQU02DataNumbersindicateEPRI'fueltypes.023ActualChangeinDensity,5

WESTINGHOUSE PROPRIETARY CUSS2Figure3.Reg.GuidePrediction ofEPRIMODataXl9)9QIQfwGQcJ32.CLOl~l3Of8~gggg0>~OI~gyOl8'bs\l7(7(ptgIXlkQ0IkOMOMechanically MixedXIMOxMastert1ixedeU02DataNumbersindicateEPRIfueltypes.~1"02'ActualChangeinDensity