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NEI White Paper: the Economic Benefits and Challenges with Utilizing Increased Enrichment and Fuel Burnup for Light-Water Reactors - Prepared by the Nuclear Energy Institute, February 2019
ML21259A191
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Issue date: 02/28/2019
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Joseph, Stacy
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TheEconomicBenefitsandChallengeswithUtilizing IncreasedEnrichmentandFuelBurnupforLightWater Reactors PreparedbytheNuclearEnergyInstitute February2019 WhitePaper

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Acknowledgements ThisdocumentwasdevelopedbytheNuclearEnergyInstitute.NEIacknowledgesandappreciatesthe contributionsofNEImembersandotherorganizationsinprovidinginput,reviewingandcommentingon thedocumentincluding NEIProjectLead:FrancesPimentel EPRIProjectManager:FredSmith TechnicalAdvisors:

StanHayes

Duke DariusAhrar

Xcel BillGassmann Exelon AndrewNicholson Dominion NicholasSzewczyk Southern MasonMackovicka GNF RodKrich

Lightbridge

Notice NeitherNEI,noranyofitsemployees,members,supportingorganizations,contractors,orconsultants makeanywarranty,expressedorimplied,orassumeanylegalresponsibilityfortheaccuracyor completenessof,orassumeanyliabilityfordamagesresultingfromanyuseof,anyinformation apparatus,methods,orprocessdisclosedinthisreportorthatsuchmaynotinfringeprivatelyowned rights.

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TableofContents 1

Introduction.....................................................................................................................................1 2

EconomicAnalysis............................................................................................................................2 2.1 TechnicalChallenges...........................................................................................................2 2.1.1 Burnup...................................................................................................................2 2.1.2 GenericSafetyAnalysis..........................................................................................2 2.1.3 DryCask.................................................................................................................3 2.1.4 Enrichment.............................................................................................................3 2.2 IndustryDemandandEconomicEvaluation.......................................................................4 2.2.1 FuelManagement..................................................................................................4 2.2.2 CapitalCosts...........................................................................................................7 2.2.3 FuelComponentUnitCosts...................................................................................8 2.2.4 DiscountRate.........................................................................................................9 2.2.5 Escalation...............................................................................................................9 2.2.6 EconomicEvaluation..............................................................................................9 2.3 Results...............................................................................................................................11 2.3.1 EconomicResults.................................................................................................11 2.3.2 HighLevelWaste.................................................................................................12 2.3.3 ImpactonCycleLength........................................................................................12 2.3.4 SummaryofResults.............................................................................................12 3

RegulatoryReview.........................................................................................................................14 3.1 FuelEnrichmentFacilities.................................................................................................15 3.2 FuelFabricationFacilities..................................................................................................15 3.3 FuelTransportation..........................................................................................................16 3.4 CriticalityIssues................................................................................................................18 3.5 SafetyAnalysis(HighBurnup&HighEnrichment)...........................................................20 3.6 MaterialControlandAccounting(MC&A)........................................................................21 3.7 PhysicalProtectionofHALEUPlantsandMaterials.........................................................22 3.7.1 HALEUinTransit..................................................................................................23 4

Conclusions....................................................................................................................................24 5

ListofOtherReferences................................................................................................................26

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1 INTRODUCTION IntheUnitedStates,commerciallightwaterreactorsgenerateelectricityusinglowenricheduranium (LEU)fuel.Onaverage,fuelcostscompriseapproximately20%ofnuclearpowerplantstotalgenerating costs.Fewotherindividualcostcomponentshavesuchalargeimpactontheeconomicsofthenuclear fleet.1Asitesfuelcostsdependontwofactors,thepriceofthefuelcomponents(uraniumfeed, conversion,enrichment,andfabrication)andtheefficiencyofthecoredesign.Fuelcomponentcostsare drivenbysupplyanddemandandarelargelyoutsidethecontrolofautility.Theefficiencyofacore designdeterminesthequantityofnuclearmaterialneededtomeetaplantsenergyobjectives.Whilea utilitycanimprovetheefficiencyofthecoredesign,thisefficiencyisultimatelylimitedbythespecific designconstraintsofthecoredesign.Twoofseveralconstraintsthathavebeenshowntodirectly impactthecoredesignefficiencyaretheuraniumenrichmentlevelanddischargeburnupachievedby thecoreand/orfueldesign.Areviewofthecurrentfuelmanagementpractices,basedonequilibrium cycledesigns,hasshownthat99%ofthevariationinfuelcycleefficiencyisattributabletovariationsin enrichmentandburnup.Manysitesarecurrentlyconstrainedbytheexistingregulatorylimitsononeor bothoftheseparameters.

Withtheincreasedinterestinhigherburnupcores,itislikelythatwithinthenextdecade,both operatingandadvancedreactorswillseeademandforfuelenrichedgreaterthan5weightpercent (wt%)U235.Thiswhitepaperprovidesastudyincludingassumptions,economicprojections,inflation andfinancialmethodologiesthatevaluatesthetechnical,financialandregulatoryissuesassociated withincreasingthelimitsonuraniumenrichmentandonfuelburnupforcurrenturaniumdioxide(UO2) fueltypes.Revisingtheselimitsimpactsalargeportionofthenuclearfuelcycleaswellasthelicensing basesforbothplantoperatorsandfuelsuppliers.Whilethereareeconomicadvantagestomakingthese changes,theyalsorequirelongtermcapitalinvestmentandregulatorychanges.Revisingtheselimits willprovidesavingsthroughadditionalcyclelengthflexibility,reducedhighlevelwastestorageand disposalrequirements,andapositivebenefitontheenvironmentalimpactofthefuelcycle.Thefinal decisiontopursuenewlimitsmustconsidernotonlytheexpectedbenefitsbutthebusinessrisks associatedwithsuchanundertaking.

1NEI,NuclearCostsinContext,October2018.

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2 ECONOMICANALYSIS 2.1 TechnicalChallenges 2.1.1 Burnup Increasingthefuelburnuplimitrequiresaddressinganumberoffuelmechanicaldesignandreliability considerations.Theseincludebutarenotlimitedto:rodinternalpressure,claddingcorrosion,rodand assemblygrowth,andcladdingstrain.Whiledemonstratingacceptablefuelperformancethatsatisfies allthesedesigncriteriarepresentsasignificanteffort,itdoesnotpresentaninsurmountabletechnical challenge.Thefuelsuppliersaredeveloping,orhavedeveloped,advancedmaterialsordesignfeatures tomitigatetheseconsiderations.Additionally,someofthefeaturesofnewaccidenttolerantor advancedtechnologyfuel(ATF)designsmayprovideadditionalsafetyperformancemarginsinthese areas.

However,issuesrelatedtofuelfragmentation,relocationanddispersal(FFRD)duringpostulateddesign basisaccidents(DBAs)remainsachallenge.FFRDhasbeenobservedinsometestreactorexperiments undersimulatedlightwaterreactor(LWR)conditions.However,theElectricPowerResearchInstitute (EPRI)withsupportfromtheU.S.DepartmentofEnergy(DOE)andincollaborationwiththeU.S.Nuclear RegulatoryCommission,OfficeofNuclearRegulatoryResearch,isconductingseparateeffecttestswhich maypotentiallyresultinafullintegratedtestin2022usingtherestartedTransientTestReactor(TREAT) atIdahoNationalLaboratorywiththemodificationsforLOCAtesting.Thisintegraltestwillbe performedunderprototypicalLWRconditions,whichcombinerealisticfueltemperatureprofiles, appropriatelinearpowerdensities,andfissiongasdistributionsappropriatetohighburnupfuelandis expectedtoadvancetheunderstandingofFFRDtosupportpotentialextensionsofexistingburnup limits.Testswithnextgenerationcladdingandfuelpelletdesignsmayalsoprovidesomeadditional insightsonthebenefitsoftheproposedATFconcepts.Thesepelletstypicallyhavealargerfuelpellet grainsizewhichhasbeenshowninseparateeffectsteststoreducenormalandtransientfissiongas releasebehaviorsduringnormalpoweroperationsandDBAs.

Asanalternativeapproach,limitingcladdingswellingandthereforetheassociatedballooningandrod burstopeningsizewillpotentiallyreducefuelmaterialrelocationanddispersalwhileensuringadequate safetymargin.Someinternationalregulatorshavealreadylicensedplantstohigherburnuplevelsusing thiscriterion.Creditingthisphenomenonwilllikelyrequirereductionsinthelinearpowerdensityasa functionofburnup.EPRIandDOEareevaluatingthepracticalityofthisapproachasabackuptothefuel fragmentationresearchstrategy.

2.1.2 GenericSafetyAnalysis Inadditiontotheexecutionofstandardcorereloadsafetyanalysismethods,somegenericanalysis methodsmaybeimpactedbyfuelburnuplimitincreases(e.g.,revisedaccidentsourcetermsanddecay heat).Afullreviewoftheexistingindustrydatabaseisneededtodetermineifsufficientmarginexistsin thecurrentanalysislimitstosafelysupporthigherburnuplimits.Potentially,additionaltestswithhigher burnupfuelmightberequired.Additionally,somesiteswilllikelyrequirerevisionstotheircurrent licensingbasiswithrespecttofuelhandlingorotheraccidentanalysesthatsupporthigheraccident sourcetermsortheadoptionofalternatesourcetermsunder10CFR50.67withappropriatelyrevised regulatoryguidance.

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2.1.3 DryCask Evaluationsofdrycaskfuelcriticality,decayheat,andsiteboundary(bothexclusionareaandlow populationzone)doselimitswillneedtobeperformedtoloadhigherburnup/enrichmentfuelindry casks.Newcertificatesofcompliance(COCs)areexpectedtoberequiredtoaddressthecriticality requirements.Currentdecayheatlimitsareexpectedtobemetwithincreasedcoolingtimes;however, methodswillneedtobedevelopedtosupportextendingthedecayheatanalysisforhigherburnupsand coolingtimes.Whilethesechangestothedesignandlicensingbasesfordrycasksystemswillrequire effort,theydonotposeasignificanttechnicalchallenge.Asignificantreductioninspentfueldischarge inventoryisexpectedwithhigherburnup/enrichments.Thisreductionwillallowlongercoolingtimesfor thesamespentfuelpoolstoragecapacity.Thisincreaseincoolingtimewillpartiallyoffsettheincrease inheatloadduetohigherburnup.Siteswithminimalstoragecapacitywillneedtodevelopan appropriatestrategypriortocommittingtohigherburnupfuel.Thesestrategiescouldincluderevising theirfuelselection,fuelloadingconfigurationsorusingacaskdesignwithhigherheatloadlimits.

Implementationofthesestrategieswillnotoccuruntilafter2035.

2.1.4 Enrichment Thelargesttechnicalchallengetoincreasingtheenrichmentlimitisrelatedtothecontrolsandanalysis tomaintaincriticalitysafetymarginsforfuelenrichmentand,fabricationfacilities,aswellasstorageand transportationsystems.ThetransportationofenrichedUF6fromthefuelenrichertothefuelsupplieris currentlyperformedusingType30Btransportationpackages.ThecurrentType30Bdesignhassufficient margintoincreasetheallowablefuelenrichmentlimittoapproximately6wt%U235.However,this licensingbasisissomewhatuniquefortransportationsystems.Itwillbechallengingtoobtainthe approvalstoextendthisanalysisassumptiontohigherfuelenrichments.Newtransportationsystems arebeingdesignedwithfixedneutronabsorberstosupportanarrayofhigherenrichments.These systemsareexpectedtobelicensedby2022.Otherfuelstorageandtransportationsystemsdonot representasignificanttechnicalbarrier.

Fueldesignedwithhigherenrichmentswillalsoincludehigherconcentrationsoffixedneutron absorberstocontrolinreactorreactivityandpowerpeaking.Thisisexpectedtolargelyoffsetthe challengesforfuelstorageandtransportation.Additionally,higherenrichedfuelwilloperatetohigher burnupswhichalsotendstooffsetcriticalityissues.Newcriticalityanalysisassumptionsmustbe consistentwiththeexpectedfueldesigns.Boththefueldesignsandstoragesystemmarginsaresite specific.Thestrategyofusingahigherconcentrationoffixedabsorbersisgenerallyexpectedtobe effectivehowever,somesiteshavelimiteddesignorstorageflexibilityandwillelecttonotadopthigher enrichmentfueldesigns.Whilerelicensinganyfuelsystemtomeetmoderncriticalityanalysisstandards posesregulatorychallenges,asdiscussedinSection3.4,theseareconsideredtobemanageablewith thecurrenttechnologyandregulatoryguidance.

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2.2 IndustryDemandandEconomicEvaluation 2.2.1 FuelManagement Fuelmanagementplansweredevelopedbasedoncurrentfueldesignsandanalysismethods.Separate EPRIsponsoredanalysesforboilingwaterreactors(BWR)andpressurizedwaterreactors(PWR)were performed2,3andarenearingpublicationinearly2019.

TheBWRanalysis2isbasedonahighpowerdensityBWR6reactoroperatingona24monthfuelcycle theBWR6shaveahigherpowerdensity,morepowerperassembly,andthereforemorerestrictive designlimitsthanBWR4s.Assuch,theBWR6resultsaremoreconservativewhenextrapolatedto BWR4s.Thefuelmanagementplansproducedequilibriumcycledesignsusinga624fuelbundlecore, operatingat3299MWt.Boththereferenceandhighenrichmentdesignsweredevelopedbasedon designswhichmaximizedtheeconomicswithintheavailabledesignmargins.Thedifferencesinthefuel managementresultsarethereforeattributabletothehigherfuelenrichmentandburnupassumptions.

TheresultsaresummarizedinTable1.NotethatthehighenrichmentcasesincludedinTable1use pelletenrichmentsashighas5.9wt%U235andachievedpeakpelletburnupsnearthetargetlimitof 80GWd/MTU.Thecurrentfueldesigncaseresultsinsignificantlymoremargintothistargetburnup limitthanthenewfuelcase.

Reload Batch Size Batch Average Enrichment

(%)

Peak Enrichment

(%)

Batch Average Discharge Burnup (GWd/MTU)

PeakPellet Burnup (GWd/MTU)

Fuel Utilization (gmU 235/MW Day)

ReferenceCase 256 4.18 4.9 48.19 62.9 0.8674 Higher Enrichment-CurrentFuel Design 240 4.39 5.9 51.40 72.6 0.8540 Higher Enrichment-NewFuelDesign1 216 4.78 5.9 57.11 79.7 0.8369 1Anewfueltypeisrequiredtooptimizethefuelperformanceathigherenrichments Table1:SummaryofBWRFuelManagementResults PWRfuelmanagementanalyses3wereperformedforbothhighpowerandlowpowerplants.Bothsets arebasedon18monthfuelcycles,theprevalentcyclelengthinthecurrentPWRfleet.Thehighpower designisbasedonaWestinghouseNSSS4loop,193fuelassemblycoreoperatingat3469MWt,based ontheWestinghouseRobustFuelAssembly(RFA)fueldesign.Thelowpowerdesignisbasedona WestinghouseNSSS3loop,157fuelassemblycoreoperatingat2775MWt,basedonaWestinghouse OptimizedFuelAssembly(OFA)fueldesign.Thelowpowerandhighpowercaseswereusedto determinethefuelmanagementefficiencyssensitivitytocorepowerandcoresize.Theefficiencywas 2ConsultingSupportforIncreasingtheEnrichmentLimit-BWRFuelManagementEvaluation,September2018.

3WestinghouseFuelManagementScopingStudy-FeasibilityofIncreasingU235EnrichmentandPeakPinBurnupLimits,November2018.

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determinedtobeproportionaltocoresize.Thehighenrichmentcasesarebasedonpelletenrichments ashighas5.95wt%U235.Boththereferenceandhighenrichmentdesignsweredevelopedusinga consistentsetofaggressivedesignlimitssothatthedifferencesinthedesignresultsreflectincreasesin enrichmentandburnup,notincreasesinpowerpeakingorotherlimits.Theresultsshowconsistent powerpeakingandboronlevels.Theeconomics(Table7and8)arebasedonthedifferenceinthefuel managementresultsbetweenthereferenceandhighenrichmentcases(Table2and3)anddonotcredit asignificantincreaseindesignlimits.However,whenhigherenrichmentandburnupsareappliedto individualsites,moreaggressivedesignlimitsmaybeneededtoobtainthefullbenefitofhigherburnup andenrichment.Therefore,existinglimitsintheareasofpeakingfactors,moderatortemperature coefficient(MTC),shutdownmargin(SDM),crudinducedpowershift(CIPS)risk,etc.maybechallenged andwillneedtobeaddressedonaplantspecificbasis.Anyrevisedlimitswillneedtobedeveloped withinexistingsafetycriteria.ThefuelmanagementresultsaresummarizedinTables2and3.

Reload Batch Size Batch Average Enrichment

(%)

Peak Enrichment

(%)

Batch Average Discharge Burnup (GWd/MTU)

PeakPin Burnup (GWd/MTU)

Fuel Utilization (gmU 235/MWd)

ReferenceCase

-averageof oddandeven cycles 76.5 4.6147 4.8 52.15 59.5 0.9002 HighEnrichment Case 60 5.6400 5.8 65.36 74.0 0.8629 Table2:SummaryofPWRFuelManagementResultsforHighPowerPlant

Reload Batch Size Batch Average Enrichment

(%)

Peak Enrichment

(%)

Batch Average Discharge Burnup (GWd/MTU)

PeakPin Burnup (GWd/MTU)

Fuel Utilization (gmU 235/MWd)

ReferenceCase

-averageof oddandeven cycles 62.5 4.8360 4.95 54.97 61.1 0.8797 HighEnrichment Case 52 5.6154 5.8 66.07 74.7 0.8499 Table3:SummaryofPWRFuelManagementResultsforLowPowerPlant Inordertoapplytheseresultstotheentirefleet,fueldesigndatafromtheEPRIFuelReliability Database(FRED)4andarecentlyheldEPRIsponsoredfuelmanagementworkshopwereusedto constructadatabaseofsitespecificreferencefueldesigns.Theburnupandfuelutilizationchanges 4 FuelReliabilityDatabase(FRED)Version5.0,3002013234

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associatedwiththeuseofhigherenrichmentswereappliedtothereferencedesigns.Thisproduceda setofsitespecifichighenrichment/burnupfueldesigns.Thisapproachsupportstheanalysisofvarious strategies,suchasamoderateburnupincreaseof67GWd/MTU.Theactualmoderateburnupincrease thatisachievablemayvarysomewhatfromthisassumptionbasedonthefueldesignspecific performanceinnormaloperationandpostulatedaccidentscenarios.Fuelcomponentrequirements (feed,enrichment,conversionandfabrication)weredeterminedforeachsite.Theresultsforthereload fuelcasesdescribedinTables13arepresentedinFigure1basedonprojectedfuelcomponentcostsin 2030.Forallcases,enrichmentexpensesincreased.Mostofthesavingscomefromfabrication(e.g.,

reducednumberoffabricatedassembliesfornewreloadbatches)withamodestcontributionfromfeed U3O8stock(e.g.,reducedamountoffeeduraniumfornewreloadbatches).Therefore,theseresultsare notverysensitivetofuturefeedorenrichmentmarketprices.

Consistentwithcurrentindustrypractice,fuelleasesandtheircorrespondingcarryingcostarenot includedinthedeterminationoffuelcosts.TheapproachisconsistentwithfuelcostreportedonFERC Form1,ElectricUtilityAnnualReportandinformalsurveysofkeyutilities.Currentlyonlyoneutility, representingapproximately5%ofthefleet,continuestoemployfuelleases.However,theuseofhigher burnupfuelwillimpacttheamortizationoffuelcosts.Smallerbatchsizeswilltendtoextendthe amortizationwhilehigherbatchaveragepowerwilltendtoaccelerateamortization.Thenetimpactof thesetwoopposingfactorsiscoredesignspecific.Also,ifasiteelectstoadopt24monthfuelcyclesas partofadoptinghigherburnupdesigns,theamortizationperiodissignificantlyreduced.

Thesitesareassumedtoimplementcoredesignsusingincreasedburnup/enrichmentlimitsbasedon economicvaluetothatsite,overan8yearperiodbeginningin2026.Thefuelcostbenefitscontinue untiltheexpectedretirementdateoftheplant.Thecurrent60yearoperatinglifeandapotential80 yearoperatinglifearebothevaluated.Theeconomicanalysesofthe80yearoperatinglifecases terminatein2067,howevertheseadditionalcycleshaveonlyamoderateimpactondiscountedcash flowsandotherprojectfiguresofmerit.

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Figure1:AnnualFuelComponentCostSavings5 2.2.2 CapitalCosts Capitalcostswereestimatedbasedonresultsfrompreviousstudies,6,7inputfromfuelservicesupplier representatives,utilityrepresentatives,andengineeringjudgment.ThecostforthemodifiedType30B UF6transportationsystemsweredeterminedbasedontheassumptionthatanextensionofthecurrent moderatorexclusionlicensingbasistohigherenrichmentswillnotbeapprovedbyNRCorinternational regulators.AsummaryoftheestimatedcapitalcostsisprovidedinTable4.Notethatthecapitalcosts varysomewhatfordifferentscenarios.Table4resultsarerepresentativeoftheexpectedtypicalcosts.

Forexample,utilitycostsvarydependingonthenumberofsitesexpectedtoimplementhigher enrichment/burnups.Thetimingofthecapitalexpendituresisbasedontheexpectedregulatory approvaldates.

5 CapitalCostarenotincluded 6StrategyforDeploymentofAdvancedFuels,RPT3005895000,September28,2011.

7OptimumCycleLengthandDischargeBurnupforNuclearFuel:PhaseII:ResultsAchievablewithEnrichmentsGreaterthan5w/o,1003217, EPRI,September2002.

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Category CapitalCosts($M)

Enrichment 20.0 UF6Transportation 21.3 Fabrication 136.0 SafetyAnalysis 10.0 BurnupExtensionDOE 7.5 Utility 79.5 DryStorage 6.0 Total 280.3 Table4:SummaryofU.S.FleetRequiredCapitalCosts(estimated)

2.2.3 FuelComponentUnitCosts Thefuturefuelcomponentcosts(feed,enrichment,conversionandfabrication)aredependenton supplyanddemandforthesecomponents.Alongtermpredictionofthesecostswasperformedbased ontheprojectedglobalnucleargenerationfromseveralsources.Theseprojectionswereprovidedto utilityparticipantsinthestudyandadjustmentsweremadebasedontheirfeedback.Onlytheminimum unitcostswereusedinthisevaluation.Asnotedpreviously,thefuelmanagementsavingsare dominatedbythefuelfabricationcosts.Fabricationcostsaresomewhatdifferentfromother componentssincetheyincludelargetechnologicalandintellectualpropertybarrierstoentry(capital investment,designandmanufacturingtechnology,regulatoryapproval).Assuch,fabricationpricesare expectedtoincreaseasaresultofinvestmentsnecessarytomanufacturehigherenrichmentfuel.

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2.2.4 DiscountRate Thediscountrateisusedincapitalallocationdecisionstodeterminethecurrentvalueofbothcostsand returnsoninvestmentwhichoccursinthefuture.Thesumofthesediscountedcashflowsprovidesthe NetPresentValue(NPV)ofaproposedproject.Projectswhichproducereturnsinexcessoftherequired discountrateareexpectedtoincreasethevalueoftheorganization(s)sponsoringtheproject.The discountrateisalsoreferredtoasthehurdlerate.Theappropriatediscountrateisdeterminedbased ontheweightedaveragecostcapital(WACC).AsshowninTable5,theWACCisdeterminedforthree largenuclearutilitiesbasedonpubliclyavailableinformation.Utilitiesoperatinginregulatedand deregulatedmarketswereselected.TheresultingWACCreflectstherequiredreturnforatypicalcapital projectofnominalrisk.Sinceanuclearrelatedprojectgenerallyinvolveshigherrisks,additionalfactors areneededtoaccountforthisadditionalrisk.Anuclearriskpremiumwasdeterminedbasedonthe accumulatedinterestpaymentsforalargenuclearconstructionproject.Theregulatoryandtechnical challengesnecessarytomodifytheenrichmentandburnuplimitshaveahigheruncertaintythana constructionprojectwhichisbasedonamaturedesign.Assuch,anadditional2.0%riskpremiumwas determinedtobeappropriate.Thisresultsina9.93%(roundedto10%)discountrateforthisproject.

WACC UtilityA

4.92%

UtilityB

6.21%

UtilityC

4.86%

Average 5.33%

NuclearRiskPremium 2.60%

ProjectSpecificPremium

2.00%

TotalDiscountRate 9.93%

Table5:EstimatedWACCforRepresentativeUtilities 2.2.5 Escalation Allfuturecashflowswereescalatedtoaccountfortheexpectedimpactofinflation.Theescalation factorsweredeterminedbasedonpublishedDepartmentofLaboreconomicindices.Theseinclude indicesforgeneralandproductionemployeecompensationandtheproducerpriceindexforindustrial commodities.Applyingdifferentweightingfunctionsresultsinescalationratesrangingfrom1.92%to 2.62%,dependingonthespecificfuelcycleactivity.

2.2.6 EconomicEvaluation Sevendifferentscenarioswereevaluatedforboth60and80yearoperatinglifeassumptions.The scenariosarelistedinTables7and8.ThesescenariosincludeindividualBWRandPWRdesignresultsas wellasvariouscombinationsofbothdesigns.ThePWRresultsconsidertwodifferentburnupincrease assumptions,aModerateBurnupof67GWd/MTUandaHighBurnupof75GWd/MTU.The ModerateBurnupcaseisestimatedtocorrespondtoalevelthatwouldbeachievediftheLOCAno

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rodburstcriteriaisapplied,asdiscussedpreviouslyinSection2.1.1.TheBWRresultsonlyconsiderone burnupincreasescenario(HighBurnup)sincetheBWRdesignsrestrictthelinearpowerdensityfor highexposurefuelassembliessotheyareexpectedtodemonstratebetterFFRDperformance.TheBWR resultsincludecurrentdesignsandafuturenextgenerationdesignwhichisoptimizedforhigher enrichments.

Allofthesescenariosassumethattheinitialreloadsbeginoperationin2026andthechangestothefuel cycleinfrastructureoccurinparalleltothetestinganddevelopmentoftheincreasedburnupdesigns.An additionalscenariowasalsoevaluatedwhichdelayedthemostsignificantcapitalinvestmentsuntilafter thehighburnupdesignstestinganddevelopment(2025)werecomplete.Thisscenarioreducestherisk associatedwithparallelactivitiesbutdelaystheinitialreloaddateto2029.

Fuelcostsavings,capitalcosts,anddrycasksavingsweredeterminedforeachscenario.Escalationwas appliedtoeachareaandtheresultswereusedtodeterminetheNPVbasedontheprojectspecific discountrate.Inaddition,theinternalrateofreturnandtheaverageannualsavingsperreactorwere alsodetermined.Theseresultsreflecttheindustrywidereturnthatisavailabletocompensatethe stakeholders(e.g.,fuelsuppliers,DOE,utilities)oftheproject.Thedistributionamongthesegroupsis subjecttocommercialdiscussionsthatarebeyondthescopeofthisstudy.However,toprovidesome perspective,estimatesweremadebasedonthefollowingassumptions:

1. Allcapitalcostswererecoveredwitharateofreturnequaltotheprojectspecificdiscountrate.
2. Nodrycaskcostsavingflowedtoutilities.
3. Thefuelfabricatorlossofrevenuecouldresultinsignificantfixedcoststhatareunrecovered.To accountforthisimpact,aportionofthefabricationsavingswasaccruedtothefabricatorsand thebalancetotheutilities.
4. DOEprovidednosignificantfinancialsupport.
5. Allfeedsavingsandincreasesinenrichmentcostareaccruedtoutilities.

TheimpactoftheseassumptionsisillustratedinTables7and8below.Adiscussionoftheseresultsis providedintheresultssectionbelow.

Inordertoestimatetheuncertaintyoftheseresults,perturbationsinkeyinputvariableswere performed.Theinputperturbationsandthecorrespondingimpactontheestimatedannualsavingsper reactor,availabletoutilities,aresummarizedinTable6.Theindividualperturbationswerecombinedas independentvariablestoprovideanestimateoftheoveralluncertainty.TheTable6resultcorresponds to13%oftheTable7resultsforthisparameter.

Theimpactofvaryingthenumberofparticipatingplantswasalsoevaluated.Thisevaluationdetermined thenumberofparticipatingplantsneededtorecoverthecapitalinvestmentincludingtheminimum requiredrateofreturn.ThisevaluationassumedonlyPWRunitsparticipateinhigher burnup/enrichmentprojects.Onlyplantswhichoperateinachallengingeconomicenvironmentwitha highexpectedreturnwereassumedtoparticipate.Iffourteen(~25%ofPWRfleet)ofthesehighpower unitsimplementhigherburnup/enrichment,thentheminimumrequiredrateofreturnisearnedforthe industry.Theaverageannualsavingforthesefourteenunitsis$0.9M/reactor.

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Perturbation

(%)

ResultingImpactofPerturbationon EstimatedAnnualSavingsperReactor AvailabletoUtilities

($M)1 UraniumFeedand EnrichmentPrice 15 0.02 FabricationPrice 10 0.14 VendorCapitalCost 25 0.07 UtilityCapitalCost 33 0.01 Total

0.16 Table6:UncertaintyinEconomicEvaluation 1ExcludesPWRLowBurnupcaseduetosmallimpact 2.3 Results 2.3.1 EconomicResults AsummaryoftheeconomicanalysisresultsisincludedinTables7and8below.Table7containsresults assumingallsitesoperatetotheendoftheir60yearlicenselife.Thisexcludessitesthathavealready publiclyannouncedearlyshutdowndates.Table8containsresultsforallsitesassuminganadditional 20yearlicenseextensionisobtainedtoreach80yearsofoperation.Eachoftheevaluatedscenarios resultsinanetpresentvaluethatexceedsthediscountrate(negativeNPV).Additionally,theresulting internalrateofreturnisprovidedtodemonstratetheexpectedreturnonthecapitalinvestment.This alsoexceedsthediscountratedevelopedabove(10%).However,notethatthereissignificantvariation inthesequantitiesaswellastheexpectedaverageannualsavingsforeachreactorcore.ForPWRunits themaximumreturnistypically25%higherthantheaveragewhileforBWRthemaximumis10%

higher.Theexpectedaverageannualsavingsarestronglydependentonthedischargeburnupassumed intheanalysis.Resultsvarybetweenapproximately$3.83M/reactorand$1.93M/reactorforpeakpin burnuplimitsof75GWd/MTUand67GWd/MTUrespectively[Table7,Column7].Sincethisdifference representsasignificantuncertaintyintheresults,additionalcaseswereevaluatedwhichshowthe impactofchangingthetimingoflicensingtherevisedburnuplimits.Thesealternativescenarioslargely mitigatetheriskoflicensingthehigherburnuplimitwithonlyaminorimpactonthevalueof implementinghigherenrichmentlimits.Theresultsfromdelayingthecapitalinvestmentuntilhigh burnupisprovenshowslightincreasesintheaverageannualsavingsavailabletoutilities.Thisisdueto theeliminationofinitial,lowercostreloads,sotheaveragevalueincreasesslightly.Thenetpresent valueandinternalrateofreturnarereduced,sincethenumberofreloadsisreducedinthiscase.

ThedevelopmentofATFdesignconceptshasthepotentialtoextendthevalueofincreasedenrichments andfuelburnuplevelsbyoptimizingfueldesignthermallimits,improvingcorrosionresistanceofthe fuelcladdingandimprovingthefuelreliabilityovercurrentdesigns.Thespecificperformanceofthe

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variousATFdesignshasnotbeenfullydeterminedatthistimeandthereforenoquantifiablebenefit regardingburnupandenrichmenthasbeenestablished.

2.3.2 HighLevelWaste Inadditiontothedirecteconomicvalueprovidedtoutilities,anincreaseinfuelenrichmentandburnup willreducethevolumeofhighlevelradiologicalwastegeneratedandsubjecttolongtermstorageand disposal.Whilethequantitiesvarybetweenscenarios,reductionsareprojectedforalltheevaluated scenarios.Forexample,the60yearoperatinglife,moderateburnupPWRonlyscenario(PWR ModerateBurnupinTables7and8)isexpectedtoreducethedrycaskstoragerequirementsby approximately200drycaskswhilethehighburnupPWR+NewBWRfueldesignisexpectedtoreduce thenumberofdrycasksbyapproximately500.

2.3.3 ImpactonCycleLength WhilevirtuallyallU.S.BWRreactorsoperateona24monthfuelcycle,onlyabout20%ofthePWR plantscanoperateeconomicallyona24monthfuelcyclewiththecurrentburnupandenrichment limits.Withamodestincreaseintheburnuplimitto67GWd/MTU,approximately68%ofthePWRfleet couldoperateona24monthcycleandallPWRplantscoulddosoifthelimitwereraisedto 75GWd/MTUalongwithanincreaseinenrichment.Thecapabilitytoachieve24monthcyclesisbased oneachsitesexpectedreloadbatchfractiondeterminedfromtherevisedburnuplimits.Siteswitha batchfractionabove50%arenotconsideredeconomicallyviablecandidatesfor24monthcycle operation.Thedecisiontoextendcyclelengthsdependsontheneteconomicvalueoftheincreasein fuelcost,reductioninreplacementpowercostandreductioninthenumberofoutagesoverthe remaininglifeoftheplant.Somecapitalcostmustalsobeconsideredtoextendsurveillanceintervals andinstrumentdriftcalculations.Whilesomeplantsmightnotelecttochangetheircyclelength,multi unitsitesandfleetswithsingleunitsitesthatsharekeyoutageresourceswouldrealizeadditional operationalbenefitsiftheychoosetotransitiontolongercycles.

Aswithpreviousindustryincreasesinfuelenrichmentandburnup,theplantswouldmoreefficientlyuse theavailablefuel.Thisresultsinamodestreductioninthedemandforuraniumoreandacorresponding reductioninuraniummining.Whilenotquantified,someenvironmentalbenefitswillberealizedfrom thischangeinthefuelcycle.

2.3.4 SummaryofResults Asdescribedabove,theriskadjusteddiscountratewasdeterminedtoaddresstheuniquefeaturesofa complexnuclearproject.Eachoftheidentifiedscenariosprovidesareturnthatexceedstherequired discountrate,indicatingtheprojectwillexceedtherequiredrateofreturn.However,thiseconomic assessmentisbasedsolelyonthisspecificprojectanddoesnotevaluateitsmeritsrelativetoother availableoptions.Additionally,thisprojectdoesrequireacommitmentfromanumberofstakeholders andsignificantchangestofuelrelatedregulatoryrequirements.However,mostPWRswouldbenefit fromthesechangesandhigherpowerBWRunitswouldalsorealizetangiblebenefits.

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Table7:SummaryofResultsfortheU.S.FleetBasedonanAssumed60YearOperatingLife

Table8:SummaryofResultsforU.S.FleetBasedonanAssumed80YearOperatingLife 60YearOperatingLifeCases FuelCost Savings

($M)

DryCaskSavings

($M)

TotalCapital Expense

($M)

Interest Expense

($M)

NetSavings1

($M)

AverageAnnual NetSavingsper Reactor1

($M)

Estimated Annual Savingsper Reactor Availableto Utilities2

($M)

Net Present Value

($M)

InternalRate ofReturn

(%)

Reactor YearsUsing Higher Enrichment NewBWRFuelDesign 643 244 143 44 700 2.89 1.13 31.78 13.0%

242 PWRHighBurnup+NewBWRFuelDesign 2480 1034 321 93 3099 3.66 1.46 251 19.2%

846 PWRHighBurnup+ExistingBWRDesign 2069 871 291 84 2565 3.19 1.23 195 18.2%

804 PWRHighBurnup 1837 790 240 70 2316 3.83 1.45 179 18.7%

604 PWRModerateBurnup 847 409 212 67 977 1.93 0.45 11 10.7%

507 PWRModerateBurnupwithtransitiontoHighBurnup 1647 712 240 70 2048 3.39 1.24 119 15.6%

604 PWR+BWRDelayCapitalInvestmentUntilHighBurnupproven 2120 867 311 106 2571 3.62 1.38 160 17.6%

711 1Fuel+DryCaskCapitalInterest 2FuelCapitalInterestEstimatedFabricationCostImpact 80YearOperatingLifeCases3 FuelCost Savings

($M)

DryCaskSavings

($M)

TotalCapital Expense

($M)

Interest Expense

($M)

NetSavings1

($M)

AverageAnnual NetSavingsper Reactor1

($M)

Estimated Annual Savingsper Reactor Availableto Utilities2

($M)

Net Present Value

($M)

InternalRate ofReturn

(%)

Reactor YearsUsing Higher Enrichment NewBWRFuelDesign 1734 966 157 47 2496 2.96 1.24 130 17.3%

844 PWRHighBurnup+NewBWRFuelDesign 9433 3540 342 98 12533 4.83 2.28 577 22.1%

2594 PWRHighBurnup+ExistingBWRDesign 7882 2951 305 87 10441 4.05 1.89 461 21.2%

2578 PWRHighBurnup 6687 2574 252 71 8938 5.11 2.31 384 21.2%

1750 PWRModerateBurnup 2736 1365 230 70 3802 3.44 1.22 99 13.9%

1105 PWRModerateBurnupwithtransitiontoHighBurnup 7374 2824 254 71 9871 5.99 2.71 334 18.7%

1648 PWR+BWRDelayCapitalInvestmentUntilHighBurnupproven 11890 3356 245 127 14875 6.29 3.60 650 24.3%

2366 1Fuel+DryCaskCapitalInterest 2FuelCapitalInterestEstimatedFabricationCostImpact

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3 REGULATORYREVIEW Thedegreetowhichexistingregulationsandguidancewillneedrevision,ornewregulatory requirementswillhavetobeestablishedandnewguidancedeveloped,dependsonthelevelof departurefromexistingfueldesigns.Thefigurebelowillustratesthecurrentandpotentialfuture enrichmentandburnupdesignlimits.

Burnup(PeakPin)

Enrichment(wt%)

20 0

10 5

15 0

40 60 80 75 62 CurrentDesigns Evaluated Possibilities FutureConcepts andDesigns

Figure2:ComparisonofDesignRanges TheregulationsinAppendixA,GeneralDesignCriteriaforNuclearPowerPlants,toU.S.Title10ofthe CodeofFederalRegulations(CFR)Part50,DomesticLicensingofProductionandUtilizationFacilities, provideprincipaldesignandperformancerequirements.Rulemakingandotherregulatoryguidance changeswillbeneededtosupporttheexpansionoftheexistingregulatoryframework.Thesafety performanceprotectedbythegeneraldesigncriteria(GDC)relatedtofueldesignandoverallfuel performanceundernormalandaccidentconditionsasrequiredper10CFR50.46willbemaintained.In additiontotheregulatoryguidancerelatedtotheGDC,theutilizationoffueldesignswithhigherburnup andhigherenrichmentcombinationsmayalsoaffectregulationsassociatedwithnuclearfuel transportation,materialcontrolandaccounting,andphysicalprotection.

Oneofthepurposesofthiswhitepaperistohighlighttheregulatoryissuesthatneedtobeaddressed toallowthemanufactureanduseofcurrentUO2fueltypeswithhigherburnupandhigherenrichment combinations.Thisreviewaddressesenrichmentsupto10wt%U235.Individuallicenseesmayelectto licensetheirfacilitiesatsomewhatlowerlevels.Thefollowingsectionsprovideaninitialreviewofthe associatedregulationsanddesigncriteriapertainingtoeachstageofthefuelcycle.

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3.1 FuelEnrichmentFacilities U.S.fuelenrichmentfacilitiesarelicensedunder10CFR70,DomesticLicensingofSpecialNuclear Material.Areviewoftheapplicableregulations,particularlyallof10CFR70,showsthatthereisno specificrestrictiononthelevelofenrichmentofspecialnuclearmaterial(SNM)thatafuelenrichment facilityisallowedtopossessonsite.Specifically,areviewof10CFR70.24,CriticalityAccident Requirements,doesnotincludealimitonenrichmentasisfoundinthecorrespondingregulationfor nuclearpowerplants,i.e.,10CFR50.68,CriticalityAccidentRequirements.Infact,theNRChas alreadyissuedalicensetoCentrusforafuelenrichmentfacility,theAmericanCentrifugePlant,which permitsenrichmentupto10%;however,thisfacilityhasnotbeenconstructed.TheNRChasalsoissued alicensetoGeneralElectricHitachiGlobalLaserEnrichmentforafuelenrichmentfacility,whichpermits enrichmentupto8%.

Itisexpectedthatcurrentlylicensedfuelenrichmentfacilitieswillrequestlicenseamendmentsto modifyexistingfacilitiestoaccommodateenrichmentsgreaterthan5.0wt%U235.Theonlycurrently operatingU.S.fuelenrichmentfacilityhasanoperatinglicensethatallowsittoenrichupto5.5wt%U 235.Inorderforthisfacilitytoincreaseenrichmentupto10wt%,thelicenseewouldberequiredto applytotheNRCforanamendmenttoitslicense.Aspartofthisamendmentprocess,thelicensee,ata minimum,wouldneedtoreviseitsNuclearCriticalitySafety(NCS)andIntegratedSafetyAnalysis(ISA) calculationsandevaluationstoreflecttheeffectsofhigherenricheduraniuminthefacilityand demonstratecompliancewithNRCrequirements.Thelicenseewouldalsoneedtoassesswhether increasingtheenrichmentfromthelicensedlimitof5.5wt%upto10wt%U235wouldnecessitatea changetotheconclusionsintheNRCsEnvironmentalImpactStatementissuedaspartofthelicensing ofthefacility.Asaresultoftheseanalyses,somemodificationofthefacilitymaybenecessary.

Accordingtostatementsfromseniorcompanyofficials,allthiscanbeaccomplished.Gettingapprovalto modifyanexistinglicensetoenrichuraniumupto10wt%U235isexpectedtotake1218monthsand requireanenvironmentalreview.

Theconclusionofthisreviewisthattherearenoregulationorrulemakingchanges,includingcriticality protectionrules,neededtoallowU.S.fuelenrichmentfacilitiestoenrichfuelupto10wt%U235.

LicensingU.S.fuelenrichmentfacilitiesforincreasedenrichmentsfrom10wt%U235wouldnotrequire revisionsorchangestotheexistingregulations.Although,NRCmaystillfindaneedtoissueapplicable guidanceforitsstaffreviewoflicenseeorapplicantsubmittals.

3.2 FuelFabricationFacilities Fuelfabricationfacilitiesarelicensedunder10CFR70,DomesticLicensingofSpecialNuclearMaterial.

Areviewoftheapplicableregulations,particularlyallof10CFR70,showsthatthereisnospecific restrictiononthelevelofenrichmentofspecialnuclearmaterialthatafuelfabricationfacilityisallowed topossessonsite.Specifically,areviewof10CFR70.24,CriticalityAccidentRequirements,doesnot includealimitonenrichmentasisfoundinthecorrespondingregulationfornuclearpowerplants,i.e.,

10CFR50.68,CriticalityAccidentRequirements.

Thecurrentlyoperatingfuelfabricationfacilitieshaveoperatinglicensesthatallowthemtoproducefuel withanenrichmentofupto5wt%U235.Inordertofabricatefuelenrichedupto10wt%U235,the licenseewouldhavetoapplytotheNRCforanamendmenttoitslicense.Aspartofthisamendment process,thelicensee,ataminimum,wouldneedtoreviseitsNuclearCriticalitySafety(NCS)and IntegratedSafetyAnalysis(ISA)calculationsandevaluationstoreflecttheeffectsofhigherenriched

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uraniuminthefacility.Thelicenseewouldalsoneedtoassesswhetherincreasingtheenrichmentof 5wt%upto10wt%U235wouldnecessitateachangetotheconclusionsintheNRCsEnvironmental ImpactStatementissuedaspartofthelicensingofthefacility.Asaresultoftheseanalyses,some modificationofthefacilitymaybenecessary.Accordingtorepresentativesofthesefacilities,theactions requiredtoobtainanamendmentfromtheNRCareachievable.Note,thesefacilitieshaverelatively smallthroughputandmaynotbeabletosupportfleetwideimplementationofhighenrichmentwithout facilitymodifications.

Additionally,therearetwoU.S.facilitieslicensedtofabricatehighlyenrichedfuelfromexistingHEU inventories,primarilyfornationaldefenseuse.TheNuclearFuelServicesfacility(Erwin,TN)andBWXT NuclearOperationsGroupplant(Lynchburg,VA)currentlyproducedfuelforreactorsrequiringgreater than5.0wt%U235(e.g.,test,medicalisotopeandresearchreactors).Thesefacilitiesproducefuel containingbothhighandlowenricheduranium,foruseintheU.S.NavalReactorsprogram.Theyalso blenddownHEUtolowerenrichments,whichcanbeusedforapplicationssuchasnonpowerreactors, aswellasforLEUforuseinexistingLWRs.WiththeirCategoryIfuelfacilitylicenses;thesefacilities couldproducefuelforHALEUreactors.Dependingonthefuelmanufacturingplanned,thesetwosites mightneedonlyminorlicenseamendmentsornoneatall,tomanufactureHALEUfuel.8 Theconclusionofthisreviewisthattherearenoregulationorrulemakingchanges,includingcriticality rules,requiredtoallowfuelfabricationfacilitiestomakefuelwithenrichmentsupto10wt%U235.

Licensingfacilitiesforreactorfuelfabricationoperationswithenrichmentsupto10wt%U235would notrequirerevisionsorchangestotheexistingregulations.Thatbeingsaid,NRCmightfindaneedto issueapplicableguidanceforitsstaffreviewoflicenseeorapplicantsubmittals.

3.3 FuelTransportation Theprincipalassuranceofsafetyinthetransportofnuclearmaterialsisthepackaging,whichmust mitigateagainstforeseeableaccidents.Typicalpackagingofuraniumhexafluoride(UF6)consistsofan innersteelcylinderthatactsasacontainmentvessel,andanouterprotectiveoverpack.Theoverpack providesthermalprotectiontopreventoverheatingoftheUF6,whichcancausehydraulicfailureofthe cylinder.Theoverpackalsoprotectsthecylinderfromimpacts.UnenrichedUF6maybetransportedin barecylinders,withouttheprotectiveoverpack,asauthorizedinDOTregulations.Protectiveoverpacks aretypicallyrequiredonlyforthetransportofenriched(fissile)UF6.Designandperformancestandards forfissileUF6packagesarestatedin10CFR71,anddesignandperformancestandardsfornonfissile UF6packagesappearinDOTregulations.ANSIN14.1andUSEC651containinformationregarding overpacks.Choiceofspecificdesignfeatures(e.g.,overpacks)tomeetregulatorystandardsisleftto designers.

Uraniumhexafluoridefeedcancontinuetobetransportedfromtheconversionfacilitytothe enrichmentfacilityusingcurrentlyapprovedcylinders;however,transportinguraniumhexafluoride enrichedabove5.0wt%fromtheenrichmentfacilitytothefuelfabricationfacilitypresentsaregulatory challenge.ThereisnoU.S.DOTapproved,commerciallyviablecylinder(i.e.,30inchandgreaterinner diameter)oroverpackformaterialthatisenrichedtogreaterthan5.0wt%U235.Currently,shipments ofuraniumhexafluoridearemadein30BcylindersandUX30overpacksthatarecertifiedformaterial upto5.0wt%enrichmentpursuanttoTables2and3of49CFR173.417.

8NEI,AddressingtheChallengeswithEstablishingtheInfrastructureforthefrontendoftheFuelCycleforAdvancedReactors,2018.

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CylindersdesignedtoholduraniumhexafluoridearequalifiedunderDOTregulations;see49CFR 173.420uraniumhexafluoride(fissile,fissileexceptedandnonfissile).Thisregulationappliestothe packagingandshipmentofanyquantitiesgreaterthan0.1kgoffissile,fissileexcepted,ornonfissile uraniumhexafluoride.Italsoincludesrequirementsonthedesign,fabrication,inspection,andthe testingandmarkingofthepackagesaswellastheapplicableCodesandStandardsformanufacturing thecylinderunderANSIN14.1.ANSIN14.1specifiesthedesignandfabricationoftheUF6cylinder.ANSI N14.1Table1,StandardUF6CylinderData,providesdetailsforthevariousUF6cylindermodelsand indicatesthemaximumenrichmentallowedforeachmodel.Additionally,NUREG1609,Standard ReviewPlanforTransportationPackagesforRadioactiveMaterials,discussesthatforthe30in.cylinder, theUF6enrichmentmustnotexceed5.0wt%U235,alongwithNUREG1617,StandardReviewPlanfor TransportationPackagesforSpentNuclearFuel,thatstatestheinitialenrichmentshallnotexceed5.0 wt%U235forthelicensingbasislimit.

InadditiontotheDOTrules,containersmustalsomeettheNRCrequirementsin10CFRPart71.

Specifically,10CFR71.55(g)(4)statesthatpackagescontaininguraniumhexafluorideonlyareexcepted fromtherequirementsofparagraph(b)ofthesectionprovidedthattheuraniumisenrichedtonot morethan5wt%uranium235.Theseprovisionsprovidethenecessaryregulatoryrequirementsto precludeaninadvertentcriticalityinthepackage.Forenrichmentsabove5wt%U235,theexception providedin10CFR71.55(g)foruraniumhexafluoridepackageswillnolongerapply.Provisionsare availabletorequestapprovalofalternativepackagedesignsthatcouldbeusedfortheshipmentof uraniumhexafluoridewithuraniumenrichmentsgreaterthan5wt%under§71.55(b)or§71.55(c).

Meritsofanewormodifieddesignthatincludedspecialdesignfeatureswouldbereviewedand approvedundertheprovisionsof§71.55,including§71.55(c).Therefore,iftheindustrymovesto enrichmentsgreaterthan5wt%U235,fuelshipperswouldneedtogetapprovalfornewpackagesthat wouldmeetthenormalfissilematerialpackagestandardsin§71.55(b),orcouldincludespecialdesign featuresthatwouldenhancenuclearcriticalitysafetyfortransportforapprovalundertheprovisionsof

§71.55(c).

DaherTLIhasdevelopedareplacementforthecurrent30Bsystem,theDN30.TheDN30hasbeen underdevelopmentforthelast10years.TheEUregulatoryauthority(France)completedtheirreview andissuedapprovalfortheDN30inDecember2018.Theinitiallicenseallowsfuelenrichedto5.0wt%

U235.DaherTLIhasalsohadtwopresubmittalmeetingswiththeU.S.NRCandsubmittedthedesign forapprovalinAugust2018withanexpectedapprovalinmid2019.

ThecompanyhasalsodevelopedamodifiedversionoftheDN30capableofcarryingfuelenrichments upto20wt%U235.ThisdesignusesthesameDN30overpackwithamodifiedUF6cylinder.TheDN30 20cylindercontainsstainlesssteeltubesthatwillincorporateneutronabsorberstosupport enrichmentsof10wt%U235or20wt%U235.Thisconfigurationhasatotalcapacityof1600kg, somewhatlessthatthecurrent30B(2267kg).Theconfigurationhasbeenanalyzedwithoutcreditfor moderatorexclusion,consistentwithANSI.N14.1.2001andISO7195.Extendingthelicensetothese higherenrichmentsisnotexpectedtorequireadditionalaccidenttesting.Thelicensingwouldrequirea revisedcriticalitysafetyanalysis.Acompletedpreliminarydesigndemonstratedacceptableperformance overarangeofmoderatorconfigurations,includingthepresenceofallowableimpuritylevels(heels).

Establishingthefinalconfiguration(s),andsubmittingandobtainingregulatoryapprovalisexpectedto take1224months.ThisdesignprovidesaviableoptiontoaddressingthetransportationofUF6, enrichedover5.0wt%U235,inatimeframeconsistentwithaninitialreloadin2026.

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PackagingdesignedtoholdnewfuelassembliesisapprovedunderDOTandNRCregulations;see49CFR 173.417,AuthorizedFissileMaterialsPackagesand10CFR71PackagingandTransportationof RadioactiveMaterial.Thispackagingisdesignedtotransportfissilematerialthatdoesnotmeetthe fissilematerialexemptionstandardsin10CFR71.55andhasatotalradioactivitylessthananA1orA2 quantitypursuantto49CFR173.435(e.g.,fresh,unirradiatednuclearreactorfuel).Fornewfuel assemblies,typicalpackagingconsistsofametaloutershell,closedwithboltsandaweathertight gasket.Aninternalsteelstrongback,shockmountedtotheoutershell,supportsoneortwofuel assembliesfixedinpositiononthestrongbackbyclamps,separatorblocks,andendsupportplates.

Dependinguponthetypeoffuel,neutronpoisonsaresometimesusedtoreducereactivity.Ifthe packageisusedtotransportindividualfuelrods,aseparateinnercontainerisoftenemployed.The contentsofthepackageareunirradiateduraniuminfuelassembliesorindividualfuelrods.Becausethe majorityofthesepackagesareforcommercialreactorfuel,theuraniumistypicallyintheformof Zircaloycladuraniumdioxidepellets.Theprincipalfunctionofthepackageistoprovidecriticality control.Themetaloutershellofthepackagingretainstheassemblieswithinafixedgeometryrelativeto othersuchpackagesinanarrayandprovidesimpactandthermalprotection.Shieldingrequirementsare notsignificantbecauseofthelowradioactivityofunirradiatedfuel.

TheconclusionofthisreviewisthatthelicensingbasisofcurrentUF6packagedesignsrestricts enrichmenttolessthan5.0wt%U235.Also,newfuelshippingpackagesarecurrentlydesignedto acceptfuelenrichedupto5.0wt%U235.Containerdesignmodificationandrelicensingwouldbe requiredtoshipuraniumhexafluorideandfreshfuelinexcessof5.0wt%U235.

3.4 CriticalityIssues Asignificantfactorinthelicensingofanyenrichmentorfabricationfacilityiscriticality.Aslicenseeslook forwaystooptimizefacilitiesandstorage/transportpackages,computersoftwaremethodsanddata usedinestablishingthecriticalitysafetyofsystemswithfissilematerialbecomemoreimportant.9For enrichmentsupto11wt%U235,criticalitybenchmarkdataisdescribedinNMSS0007,anNRC guidancedocument.NMSS0007identifiedtheneedtodevelopandconfirmtheadequacyofmethods, analyticaltools,andguidanceforcriticalitysafetysoftwaretobeusedinlicensingnuclearfacilities.

Computercodesusedforcriticalitycalculationsmustbebenchmarkedagainstcriticalexperiments thatrepresentthespecificfissilematerials,configurations,moderation,andneutronpoisoning conditionsthatrepresentthefacilitybeinglicensed.However,itiswellrecognizedthatexisting criticalbenchmarkexperimentswillneverpreciselymatchtheseconditions.Inaddition,thereare fewerbenchmarkexperimentsthatareavailableathigherenrichmentranges[e.g.,between5to 20percentandlowermoderation(i.e.,H/X,whereHishydrogenandXisfissilemedia)]ranges, thatcouldbeoffutureinteresttopotentialapplicants.Methodsareneededtoextendtherangeof applicabilityofcurrentbenchmarkexperimentsviasensitivity/uncertainty(S/U)analysis techniques.

NMSS0007goesontostatethat:

NMSShasperformedextensiveworkwithOakRidgeNationalLaboratory(ORNL)tofurther developcriticalitysafetycomputercodes[e.g.,StandardizedComputerAnalysesforLicensing Evaluation(SCALE)]toaddressthesechallenges.ThefinalreportsfortheS/Umethodswere 9ResolutionofGenericSafetyIssues:NMSS0007.CriticalityBenchmarksGreaterthan5%Enrichment(Rev.2)(Section6ofNUREG0933,Main ReportwithSupplements1-34)December2011.

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publishedinNovember1999asVolumes1and2ofNUREG/CR6655.Thereportscoverthe followingsubjects:(1)methodologyfordefiningrangeofapplicabilityincludingextensionsof enrichmentsfrom5to11percent;(2)testapplicationsandresultsofthemethod;(3)test applicationforhigherenrichmentsusingforeignexperiments;(4)feasibilitystudyforextendingthe methodtomultidimensionalanalyses,suchastransportcasksandreactorfuel.

NMSS0007concludesthattheresultsofthetestapplicationsoftheORNLmethodsshow:

.forsimplegeometrieswithneutronspectrathatarewellmoderated(highH/X),benchmark experimentsat5percentenrichmentareapplicabletocalculationsupto11percentenrichment.

Forenrichmentsabove11wt%U235,theOakRidgeNationalLaboratory(ORNL)methodprovides sensitivityanduncertaintyinformation,tohelpdesignersallowadequatelylargemarginstocoverthe lackofbenchmarkvalidation.GuidancetotheNRCstaffisprovidedinFuelCycleSafetyand SafeguardsInterimStaffGuidance10,Revision010,whichclarifiestheminimummarginofsubcriticality forsafetyrequiredforalicenseapplicationoranamendmentrequestunder10CFRPart70,SubpartH.

Criticalityaccidentrequirementsforthespentfuelpoolofanuclearpowerplantarefoundin10CFR 50.68or10CFR70.24.Theseregulationsspecifyrequirementsforlicenseestomaintaineithera criticalitymonitoringsystem(10CFR70.24)ordesignmargintocriticalityaccidents(10CFR50.68).10 CFR50.68includesacceptancecriteriawhichensurethatadequatesafetymarginsaremaintainedand requiresthemaximumenrichmentoffreshfueltobelimitedto5wt%U235.Thisadditionallimitation doesnotprotectthecriticalitysafetymargins,sincemanyotherindependentparametersimpactsafety margins.Theseinclude,amongothers,thepresenceofintegralneutronpoisonsinthefuelassembly, poisoninsertsinthestoragerackandfuelstorageconfigurations.Thespecificcombinationsof parameterswhichdoprotectcriticalitysafetymarginsaredescribedineachfacilityslicensingbases.

WiththepotentialneedtoincreaseenrichmentlevelsforbothexistingcommercialLWRreactorsand advancedreactors,theappropriateactionistoremovespecificenrichmentlimitsfrom10CFR50.68.

Retentionofthenecessaryenrichmentlimitsinthefacilitylicensingbases,includingTechnical Specifications,providesadequateprotectionforcriticalitysafetymargins.Also,theuseofexemption requestsasaparallelpathcontingencytosupportthetimelinefor10CFR50.68rulemakingisanoption.

Inadditiontotheregulationsandguidancedocumentsdescribedabove,severalguidancedocuments wereidentifiedwhereintheuseofenrichmentsupto10%ortheburnupassumptionswouldneedtobe addressed.

Section7.5.2ofNUREG153611states,inpart,Althoughtheburnupofthefuelaffectsitsreactivity, manycriticalityanalyseshaveassumedthecasktobeloadedwithfreshfuel(thefreshfuelassumption).

Alternatively,theNRCstaffhasprovidedguidanceforlimitedburnupcreditforintactfuel.Thisguidance iscurrentlylimitedtoburnupcreditavailablefromactinidecompositionsassociatedwithUO2fuelof5.0 wt%orlessenrichmentthathasbeenirradiatedinaPWRtoanassemblyaverageburnupvaluenot exceeding50GWd/MTU[increasedto60GWd/MTUindraftNUREG2215]andcooledoutofreactor foratimeperiodbetween1and40years.

Withrespecttocriticalityatthereactorsites,thereisanopportunitytoimprovetheanalysesby relaxinganumberofexcessiveconservatisms.BaseduponareviewoftheNRCsourcesanddiscussions 10USNRC,FuelCycleSafetyandSafeguardsInterimStaffGuidance10,Revision0(FCSSISG10,Revision0),ML061650370 11USNRC,NUREG1536StandardReviewPlanforSpentFuelDryStorageSystemsataGeneralLicenseFacility,Revision1,July2010

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withseveralsubjectmatterexperts,itisclearthatnumerousexcessiveconservatismshavecreptinto thesecriticalityanalyseswhichdonotexistinotherareasofdesign,analysis,andoperation.Thiscould potentiallyallowhigherenrichmentsabove5.0wt%U235tobeutilizedwithoutsignificantredesignof structures,systems,orcomponents.Theseconservatismscouldinclude,forexample,additionalcredit forfissionproductpoisonsorcreditforBWRburnupbeyondpeakreactivity.Additionally,thedesignof coresusinghigherenrichedfuelwouldalsorequireincreasedconcentrationsofneutronpoisonsto meetcorelimits,andfuelwillachievehigherburnup,whichalsoreducesreactivity.Theadditional poisonconcentrationsandhigherburnupareexpectedoffsetthereactivityeffectsofhigher enrichment.Asisthecurrentcase,someassemblieswillnotmeettheenrichmentburnuprequirements, sostorageinhighlypoisonedracksorincheckerboardorotherconfigurationswillberequired.

3.5 SafetyAnalysis(HighBurnup&HighEnrichment)

Thistopicconsidersbothanincreaseinpelletenrichmentandanincreaseinfuelrodaverageburnup beyondcurrentlyapprovedlimits.Manyutilitiesneedthecombinationofincreasedfuelburnupand increasedenrichmenttoachievetheireconomicgoals.Thediscussionbelowfocusesontheissues identifiedduringtheregulatoryreviewthatwouldneedtobeaddressedtosupportanenrichment increaseupto10wt%U235andanincrementalincreaseinburnupto75GWd/MTUrange.

Proposedrulemakingfor10CFR50.46cwouldlimitfuelrodburnupsduetoNRCconcernswithfuel fragmentationaftercladdingrupture.Itisassumedthatthefuelfragmentationquestionwillbe addressedbyalicenseeseekinghigherfuelrodburnupsevenifrulemakingdoesnotproceed.Thereare effortscurrentlyunderwaytoaddressthisconcern.EPRIisconductingresearchthatisexpectedtoresult inalinearheatratelimitversusburnuptoprecludefuelfragmentation.Additionally,fuelvendorsare lookingathowcalculationscandemonstratethathighburnuprodsdonotrupturefollowingaLOCA.

Reactivityinsertionaccidentswillalsoneedtobeevaluated.Itisexpectedthatmostsiteswillnot exceedPCMIortemperaturelimits,sofuelfragmentationisnotexpectedtobeanissue.EPRIisalso evaluatingtheindustryneedsinthisarea.

Utilities(withtheexceptionofthosenonGDCplantswhociterequirementsspecifictotheirlicensing basis)andvendorstypicallyuseNUREG080012todemonstratehowtheymeetGeneralDesignCriteria 10(see10CFR50,AppendixA).Thesoftwareandmethodsusedtodemonstratecomplianceare approvedbytheNRC.ForPWRs,theNRClimitstheapplicabilityofcodesandmethodstonomorethan 62GWd/MTU.Resolutionofthefuelfragmentationissueisneededtopermithigherburnups.There mayalsobeanimpliedlimitationof5.0wt%U235enrichmentforcodesandmethods,ifnotspecific limitationsandconditions,whichwouldrequirethemtoberelicensedforahigherenrichment.Any necessarychangestothecurrentfuelperformancecodesandmethodsshouldbeabletosupporta modestburnupincreaseinthe6768GWd/MTUrangewithlowregulatoryrisk.Burnupsbeyond68 GWd/MTUmayrequireadditionalfuelperformancedatatovalidatethesoftwaremodels.AttheEPRI sponsoredworkshoponBurnupandEnrichmentinDecember2018,theNRCwasgenerallysupportiveof moderateburnupincreasesandopentoaphasedapproachtohigherburnupincreasesafterwards.

ThereareseveralRegulatoryGuides(RegGuide)thatcontainfissionproductdatafordoseanalysis calculations.Forexample,RegGuide1.183andRegGuide1.195bothstatethatthereleasefractions listedintheguideshavebeendeterminedtobeacceptableforusewithcurrentlyapprovedLWRfuel withapeakrodburnupupto62GWd/MTUprovidedthatthemaximumlinearheatgenerationrate 12NUREG0800,"StandardReviewPlanfortheReviewofSafetyAnalysisReportsforNuclearPowerPlants:LWREdition"

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doesnotexceed6.3kW/ftpeakrodaveragepowerforburnupsexceeding54GWd/MTU.Existing regulationslimittheuseofthesereleasefractionstoenrichmentsbelow5wt%U235.Theseregulatory guideswillneedtoberevisedtoextendtheirapplicabilitytosupporthigherburnupsandenrichments forimplementationofhigherleadrodburnuplimits.

Addendum1toVolume1ofNUREG-1437,GenericEnvironmentalImpactStatementforLicense RenewalofNuclearPowerPlants,(NRC1999),statesthattheenvironmentalimpactswouldbesmall fortransportingspentfuelenrichedwithupto5.0wt%U235withanaverageburnupforthepeakrod ofupto62GWd/MTU.Italsostatesthat,ifpeakfuelburnupisprojectedtoexceed62GWd/MTU and/orfuelisenrichedtohigherlevels,licenserenewalapplicantsmustsubmitanassessmentofthe implicationsfortheenvironmentalimpactvaluesreportedin10CFR51.52.Utilitieswouldneedto considerwhetheranylicensingactionsareneededforcurrentoperatinglicensesorrenewedlicenses withrespecttoenvironmentalimpactstatementsforhigherburnupsandenrichments.

Asdiscussedin10CFR50.61(FractureToughnessRequirementsforProtectionAgainstPressurized ThermalShockEvents),calculationsforvesselfluenceincludeassumptionsforcoreloadingpatterns.

Vesselfluenceonlyconsidersneutronsover1MeV,butitisnotclearhowtheenergyspectrumwillshift duetothecombinationofhigherburnup,increasedenrichment,andmore/differentburnable absorbers.Fromaprogrammaticstandpoint,eveniftheendoflifefluenceisincreasedonlyslightly,the plantscurrentpressuretemperaturecurves(whichresideineithertheplantTechnicalSpecificationsor thePressureTemperatureLimitsReportforITSplants)willneedtobereanalyzedtodetermineifthe validEffectiveFullPowerYearlimithasdecreased.Thisisespeciallyaconcernforplantsconsidering secondlicenserenewal(SLR).

IntheStandardTechnicalSpecifications(4.2.1,FuelAssemblies),allowablefuelpelletsarethosewithan initialcompositionofnaturalorslightlyenricheduraniumdioxide(seeRef.25,forexample).Therefore, nochangestothisStandardTechnicalSpecificationwouldbeneeded.

Inconclusion,thereareseveralareas,suchasfissionproductinventoriesfordoseanalysesandthe licensingoffuelperformancecodes,whichwillneedtobeaddressedaschangemanagementitems.

Whilethereareeffortscurrentlyunderwaytoaddressfuelfragmentation,resolutionoftheNRC'sfuel fragmentationconcerniscriticaltomovingforwardwithincreasedfuelrodburnups.

3.6 MaterialControlandAccounting(MC&A)

AnMC&Aprogramisthewayafacilityoperatorconductsasustainable,effectivegradedsafeguards programforthecontrolandaccountingofnuclearmaterials,todetectanddetertheftanddiversionof SNM.TheMC&Aprogramimplementsadefenseindepthapproachtoensurethatallaccountable nuclearmaterialsareintheirauthorizedlocationandbeingusedfortheirintendedpurposes,suchthat singlecomponentfailureswillnotresultinsignificantvulnerabilities.ThegoalofMC&Aisto(1)maintain currentknowledgeofthelocationofSNMandresolveanydiscrepanciesand(2)preventundetected accessresultinginunauthorizedchangestoquantitiesofSNMatasitethatmightultimatelyresultin diversionofSNM.MC&AalsocomplementsinternationaltreatyobligationsbyaccountingforSNMat facilitiesandreportingthequantityofSNMatthosefacilities,asappropriate,totheInternational AtomicEnergyAgency(IAEA).Asprovidedby10CFRPart70.22(b),theruleappliestoeachapplicantfor alicensetopossessspecialnuclearmaterial,topossessequipmentcapableofenrichinguranium,to operateanuraniumenrichmentfacility,topossessanduseatanyonetimeandlocationspecialnuclear materialinaquantityexceedingoneeffectivekilogram(withexceptionsforcertainenduserslicensed

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underotherregulations).Theentityseekingalicensemustprovideanapplicationwhichcontainsafull descriptionoftheapplicantsprogramforcontrolandaccountingofsuchspecialnuclearmaterialor enrichmentequipmentthatwillbeintheapplicantspossessionunderlicensetoshowhowcompliance withtherequirementsoftheapplicable10CFR74requirementsareaccomplished.

NRCprovidesclearguidanceoncompliancewith10CFR74(MaterialControlandAccountingofSpecial NuclearMaterial)intheformoftwodocumentspreparedbytheNRC,NUREG1065andNUREG1280 forfacilitiesinvolvedwithCategoryIIIandCategoryISNMquantitiesdefinedin10CFR70.4, respectively.ThesedocumentsprovideguidanceonestablishingaFundamentalNuclearControlPlan (FNMCP)thatdescribeshowtherequirementsof10CFR74.31section(c)SystemCapabilities(1) through(8)aremet.MC&Anuclearmeasurementnondestructiveassay(NDA)isdescribedinchapter3 ofNUREG1065andchapter4ofNUREG1280.NDAbasedoninterrogationofU238(ortotalU)arenot directlyaffectedbyenrichmentchangesofthetypebeingcontemplated.However,NDAsystemsbased oninterrogationofU235willbedirectlyaffectedbyanenrichmentchangeandthereforethosesystems mayneedtoberequalified.

Inaccordancewith10CFR74.31(b),eachapplicantforalicense,andeachlicenseethat,upon applicationformodificationofitslicense,wouldbecomenewlysubjecttotheperformanceobjectivesof 10CFR74.31(a)ofthatsection,shallsubmitanFNMCplandescribinghowtherequirementsof paragraph(c)ofthatsectionwillbemet.TheFNMCplanshallbeimplementedwhenalicenseisissued ormodifiedtoauthorizetheactivitiesbeingaddressedinparagraph(a)ofthissection,orbythedate specifiedinalicensecondition.

Inconclusion,theregulationsandassociatedguidancedonothaveassayspecificlimits,andnorule changesinMC&Awouldberequiredtoallowforanassayofupto10wt%U235.However,a modificationtothefacilitylicensemaybeneeded,updatingtheFNMCplan,becauseNDAsystems basedoninterrogationofU235willbeaffectedwhenenrichmentofU235isincreased.

3.7 PhysicalProtectionofHALEUPlantsandMaterials 10CFR70.22(k)requireslicenseapplicantsseekingtopossessSNMof10kgormoreoflowstrategic significance(exceptthosewhoarelicensedtooperateanuclearpowerreactorpursuantto10CFR50) toincludeaphysicalsecurityplanthatdemonstrateshowtheapplicantwillmeettherequirementsof 10CFR73.67(f).Theplanmustaddresshowandwherethematerialistobestored,howaccessis controlled,andprovisionsforawatchmanoroffsiteresponseforcetorespondtoallunauthorized penetrationsoractivities.Additionally,writtenresponseproceduresdealingwiththreatsoftheftof thesematerialsmustbeestablishedandmaintained.

Thephysicalprotectionrequirementsaregenerallygradedbasedontheriskofthematerialbeingused formalevolentpurposes.TheprincipalRGsusedinlicensingCategoryI,IIandIIIfacilitiesareRegGuide 5.52,StandardFormatandContentofaLicenseePhysicalProtectionPlanforStrategicSpecialNuclear MaterialatFixedSites(OtherthanNuclearPowerPlants)(NRC,Rev.3,1994);RegGuide5.55, StandardFormatandContentforSafeguardsContingencyPlansforFuelCycleFacilities(NRC,1978b);

andRegGuide5.59,StandardFormatandContentforaLicenseePhysicalSecurityPlanforthe ProtectionofSpecialNuclearMaterialofModerateorLowStrategicSignificance(NRC,Rev.1,1983).

Thisreviewdidnotidentifyanyregulatoryobstaclesforthecurrentlicensesforfuelenrichmentorfuel fabricationfacilitieswhenenrichingfuelupto67wt%U235.Currentlicensesoffabricationand enrichmentfacilitiesallowforpossessionofSNMoflowstrategicsignificancewhich,bydefinition,

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includesgreaterthanorequalto10,000gramsofSNMwithenrichmentsupto10wt%U235.

Therefore,nomodificationstothefacilitiessecurityplansandnorevisionsorchangestoexisting physicalprotectionregulationswouldberequiredtosupportenrichmentincreasesupto10wt%U235.

3.7.1 HALEUinTransit Performanceobjectivesofthephysicalprotectionsystemsintransitaredescribedin§73.67(g)for CategoryIIImaterials.CategoryIIISNMmaterial,alsoreferredtoasSNMoflowstrategicsignificance,is definedas10,000gramsormoreofU235containedinuraniumenrichedabovenaturalbutlessthan10 percentU235.Inwayssimilartothefixedfacilityphysicalprotectionrequirements,physicalprotection requirementsformaterialintransitarealsogradedbasedonrisk.Theconclusionofthisreviewisthat therearenoregulatoryobstaclesforHALEUintransitwhenincreasingenrichmentsupto10wt%U235.

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4 CONCLUSIONS Thereareanumberoftechnicalchallengesthatwillneedtobeaddressedtodemonstratecompliance withexistingsafetycriteriapriortoimplementinghigherburnupandhigherenrichmentcombinations withcurrentfueldesigns.Oneofthechallengesassociatedwiththeinitialdeploymentofhigher burnup/enrichedfuelsforthecurrentLWRfleetisthatneitherthedesignersnorfuelproducerscan proceedpastacertainpointwithouttheother.Earlyintheprocess,developersofeithercannotbe certainthattheotherisactuallygoingtoreachcommercialdeployment.Thelengthoftimeittakesto gaincommercialsupportforfunding,addresstechnicalandregulatoryissuesandthenconstructthe necessaryfuelcycleinfrastructurecreatesspecialchallengesforrealizingthesechanges.Inorderto addressthesechallengesitbecomesimperativethatthefederalgovernmentandtheindustrywork togethertorealizethebenefitsassociatedwiththeuseofhigherburnup/enrichedfuels.

EachoftheidentifiedscenariosintheeconomicanalysisdiscussedinSection2.0,providespositive economicbenefitsfortheU.S.nuclearfleet.Theuseofhigherburnupfueldesignsresultsinareduction inhighlevelwasteandthecorrespondinginvestmentindrycaskstoragesystems.Additionally,most PWRscouldincreasetheiroperatingscheduleflexibilitypotentiallyresultinginfewerrefuelingoutages andincreasedenergyproduction;however,thesebenefitsareplantdependentandnotcreditedinthe economicanalysis.Thisprojectalsorequiresacommitmentfromanumberofstakeholdersincluding fuelsuppliers,plantoperators,andgovernmentagencies.Fuelmanagementbenefitsaredominatedby fuelfabricationsavingsforutilities.Estimatedfuelfabricationpriceincreasesareincludedinthe analysis;however,theactualincreasesaresubjecttocommercialnegotiations.Commitmentbyatleast sixteenlargePWRcommercialreactorsisestimatedtoprovidetheminimumrequiredreturnforthe project.

Tosupportthisinitiative,changestotheregulatoryframeworkwillbeneededtochangeoreliminate themaximumenrichmentlimitof5.0wt%U235.Withthepotentialneedtoincreaseenrichmentlevels forbothexistingcommercialLWRreactorsandadvancedreactors,removalofspecificenrichmentlimits from10CFR50.68isthemostappropriateaction.Thespecificcombinationsofparametersthatprotect criticalitysafetymarginsaredescribedinthefacilitieslicensingbasisdocuments.Theseparameters include,amongothers,thepresenceofintegralneutronpoisonsinthefuelassembly,poisoninsertsin thestoragerack,boratedwaterrequirements,andfuelstorageconfigurations.Retentionofthe necessaryenrichmentlimitsinthefacilitylicensingbasis,includingTechnicalSpecifications,provides adequateprotectionforcriticalitysafetymarginstosupportremovalofthespecificenrichmentlimit from10CFR50.68.

FederalgovernmentsupportofdevelopmentofLeadUseAssemblies(LUAs)tobeusedfortestingwill beneeded.AtpresenttheonlyU.S.sourceforuraniumenrichedtogreaterthan5.0wt%U235would beuraniumproducedfromdownblendinggovernmentownedhighenricheduranium(HEU).Sometest reactorfuelmaybeavailabletoprovideLUAquantities.WhileDOEcouldtheoreticallyprovidealimited sourceofgreaterthan5.0%enrichedU235throughdownblending,thisoptionisconstrainedbythe availabilityofHEU.Thus,thisapproachcouldbeastopgapstrategybutcannotberelieduponasalong termfuelsource.13 13AddressingtheChallengeswithEstablishingtheInfrastructureforthefrontendoftheFuelCycleforAdvancedReactors,NuclearEnergy Institute,January2018.

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U.S.governmentassistancewillalsobeneededtoamendfacilitylicensesandmakenecessary modificationstosupportanincreaseinenrichmentforbothfuelenrichmentandfuelfabrication facilitiesinadditiontolicensechangesassociatedwithtransportationissues.Amendinganexisting licensetoenrichupto10wt%U235isexpectedtotake11.5yearsandtheestimatedtimetomodifya facilitytohandleenrichmentsfrom510wt%U235is1year.

NRCstaffhasrecognizedthroughstakeholderinteractionsthatrequestsforincreasedfuelburnups, beyondthecurrentlicensedlimits,areverylikelytooccur.Assuch,ithasbegunassessingthecurrent knowledgeandexperimentaldataassociatedwithhighburnupfuels,beginningwithNUREG/CR6744, PhenomenonIdentificationandRankingTables(PIRTs)forLossofCoolantAccidentsinPressurizedand BoilingWaterReactorsContainingHighBurnupFuel.14NRCstaffhasalsoindicatedthatitexpects industrydecisionsontargetedmaximumburnupswilldirectfutureplansinregardstoanassociated increaseinenrichmenttoefficientlyachievethedesiredburnup.So,alongwithworkassociatedwith increasedfuelburnups,thestaffisbeginninganassessmentofwhatenrichmentincreasethecurrent knowledgeanddatabasecouldalsosupportwithrespecttolicensingaccidenttolerantfuels.15Future workinthisareawillidentifythenextstepsandimplementationstrategy.

Issue PotentialPathForward Regulationslimitingenrichmentto 5wt%U235.

Initiatenewrulemakingtoeliminatethelimitof5.0wt%U235 from10CFR50.68basedonretentionofthenecessaryenrichment limitsinthefacilitylicensingbases,includingTechnical Specifications,providingadequateprotectionforcriticalitysafety margins.

Provisionsareavailabletorequestapprovalofalternativepackage designsthatcouldbeusedfortheshipmentofuranium hexafluoridewithuraniumenrichmentsgreaterthan5wt%under

§71.55(b)or§71.55(c).Meritsofanewormodifieddesignthat includedspecialdesignfeatureswouldbereviewedandapproved undertheprovisionsof§71.55,including§71.55(c).

Resolutionoffuelfragmentation issue Ongoingresearchisexpectedtoresultinalinearheatratelimit versusburnuptoprecludefuelfragmentation.Additionally,tests areplannedtodemonstratethathighburnuprodsdonotrupture followingaLOCA.Reactivityinsertionaccidentswillalsoneedtobe evaluated.

Newfuelshippingpackagesare currentlydesignedtoacceptfuel enrichedupto5.0wt%U235.

Containerdesignmodificationandrelicensingwouldberequired toshipfreshfuelinexcessof5.0wt%U235.

Table9:KeyIssuesandPathForward

14ADAMSAccessionNo.ML013540584 15ADAMSAccessionNo.ML18261A414

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5 LISTOFOTHERREFERENCES

1) ANSIN14.12001
2) 10CFRPart50,DomesticLicensingofProductionandUtilizationFacilities
3) 10CFRPart51,EnvironmentalProtectionRegulationsforDomesticLicensingandRelated RegulatoryFunctions
4) 10CFRPart70,DomesticLicensingofSpecialNuclearMaterial
5) 10CFRPart71,PackagingandTransportationofRadioactiveMaterial
6) 10CFRPart73,PhysicalProtectionofPlantsandMaterials
7) 10CFRPart74,MaterialControlandAccountingofSpecialNuclearMaterial
8) 10CFRPart75,SafeguardsonNuclearMaterialImplementationofUS/IAEAAgreement
9) 49CFRPart173.420,Uraniumhexafluoride(fissile,fissileexceptedandnonfissile
10) ArgonneNationalLaboratorywebsite.Web.ead.anl.gov/uranium/guide/uf6/index.cfm
11) NRCWebsite,https://www.nrc.gov
12) ResolutionofGenericSafetyIssues:NMSS0007.CriticalityBenchmarksGreaterthan5%Enrichment (Rev.2)(Section6ofNUREG0933,MainReportwithSupplements1-34)December2011
13) DOESTD11942011,NuclearMaterialsControlandAccountability,June2011
14) NUREG1520,Rev.2,StandardReviewPlanforFuelCycleFacilitiesLicenseApplications,June2015
15) U.S.NuclearRegulatorystaffguidance,FuelCycleSafetyandSafeguardsInterimStaffGuidance10, Revision0(FCSSISG10,Revision0),ADAMSAccessionNo.ML061650370
16) NUREG1280,Rev.1,StandardFormatandContentAcceptanceCriteriafortheMaterialControl andAccounting(MC&A)ReformAmendment,10CFRPart74,SubpartE,IssuedApril1995(for highenricheduraniumfacilities)
17) NUREG1065Rev.2,AcceptableStandardFormatandContentfortheFundamentalNuclear MaterialControl(FNMC)PlanRequiredforLowEnrichedUraniumFacilities,IssuedDecember 1995
18) NUREG1748,EnvironmentalReviewGuidanceforLicensingActionsassociatedwithNMSS Programs,issuedAugust2003(providesgeneralproceduresfortheenvironmentalreviewof licensingactionsregulatedbytheOfficeofNuclearMaterialSafetyandSafeguards)
19) DraftNUREG2215,StandardReviewPlanforSpentFuelDryStorageSystemsandFacilities,draft reportforcommentNovember2017

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20) NUREG1617,StandardReviewPlanforTransportationPackagesforSpentNuclearFuel,March 2000
21) NUREG1437,GenericEnvironmentalImpactStatementforLicenseRenewalofNuclearPower Plants,(NRC1999)
22) RegulatoryGuide1.183,"AlternativeRadiologicalSourceTermsforEvaluatingDesignBasis AccidentsatNuclearPowerReactors,"July2000
23) RegulatoryGuide1.195,MethodsandAssumptionsforEvaluatingRadiologicalConsequencesof DesignBasisAccidentsatLightWaterNuclearPowerReactors,May2003
24) NUREG0800,"StandardReviewPlanfortheReviewofSafetyAnalysisReportsforNuclearPower Plants:LWREdition"
25) NUREG1431,"StandardTechnicalSpecificationsWestinghousePlants"
26) USNRC,FuelCycleSafetyandSafeguardsInterimStaffGuidance10,Revision0(FCSSISG10, Revision0),ADAMSAccessionNo.ML061650370
27) ADAMSAccessionNo.ML013540584NUREG/CR6744,PhenomenonIdentificationandRanking Tables(PIRTs)forLossofCoolantAccidentsinPressurizedandBoilingWaterReactorsContaining HighBurnupFuel,December2001.
28) ADAMSAccessionNo.ML18261A414ProjectPlantoPreparetheUSNRCforEfficientandEffective LicensingofAccidentTolerantFuels,September2018.
29) StrategyforDeploymentofAdvancedFuels,RPT3005895000,September28,2011.
30) NUREG1609,StandardReviewPlanforTransportationPackagesforRadioactiveMaterial,March 31,1999.
31) 49CFRPart173.417,Authorizedfissilematerialspackages

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