ACRS MEETING WITH THE U.S. NUCLEAR REG ULATORY COMMISSION

8/3/2019 ACRS MEETING WITH THE U.S. NUCLEAR REG ULATORY COMMISSION

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U.S.NRCUnited States Nuclear Regulatory CommissionProtectingPeopleand theEnvironment

ACRS MEETING WITHTHE U.S. NUCLEAR

REGULATORYCOMMISSION

June 6, 2011.1


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SU.S.NRCUnited States Nuclear Regulatory CommissionProtectingPeopleand theEnvironment

Overview

Said Abdel-Khalik

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Events at Fukushima* ACRS has been actively engagedon event follow-up and discussion

of lessons-learnedandrecommendations for appropriatefollow-up actions for NRC

* ACRS Fukushima Subcommitteehas been formed

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Events at Fukushima (cont.)* ACRS has received briefings fromNRC staff and other stakeholders and

plans to hold additionalSubcommittee meetings- Overview on April 7, 2011- Near term review on May 26, 2011- Additional briefings to be scheduled

*ACRS report to the Commission onstaff's Lessons-Learned report-Prior to February28, 2012

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Accomplishmentsi Since our last meeting with the

Commission on November 5, 2010,we issued 32 Reports:

i Topics:- CurrentState of Licensee Efforts toTransition to NFPA-805- Comparison of ISA and PRA for Fuel

Cycle Facilities- Use of Risk Insights to Enhance theSafety Focus of Small ModularReactor

Reviews5


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* Topics (cont.):- APIO00

" Design CertificationAmendmentApplication

" Long-Term Core Cooling" Aircraft Impact Assessment" Vogtle Units 3 & 4 Reference COLA" VC Summer Unit 2 &3 SubsequentCOLA

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Topics (cont.):- Use of CAP in Analyzing ECCS andContainment Heat Removal System

Pump Performance n PostulatedAccidents- Emergency PlanningRule and Related

Regulatory Guidance- Safety Culture Policy Statement- SRP for Renewal of Spent FuelDryCask Storage Licenses andCertificatesof Compliance

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* Topics (cont.):- PointBeach Extended Power Uprate- RAMONA5-FA Code for Use in BWR

Stability Calculations- Revisions to Generic License

Renewal Guidance Documents- FinalSERs Associated with theLicense Renewal Applications for:

" Palo Verde NuclearStation* Kewaunee Power Station"Salem Nuclear GeneratingStation

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* Topics (cont.):- SER Related to the Calvert CliffsCQLA Referencing the EPR Design- Response to EDO Regarding Closure

of DAC for New Reactors- QualityAssessment of Selected NRCResearch Projects- Advanced Reactor Research Plan- GroundwaterProtection Task Force

Efforts- Human FactorsConsiderations

Associated with EmergingTechnologies

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* Topics (Cont.):- Regulatory Guides" RG 1. 174, An Approach for UsingPRA in Risk-Informed Decisions onPlant-Specific Changes to the

Licensing Basis" RG 1. 177, An Approach for Plant-Specific, Risk-InformedDecisionmaking:TechnicalSpecifications" RG In 152, Criteria or the Use ofComputers in Safety Systems ofNuclearPower Plants

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* Topics (Cont.):- Regulatory Guidesa RG 1.34, Controlof ElectroslagWeld Properties

w RG 1.43, Controlof Stainless SteelWeld Cladding of Low-Alloy SteelComponents

mRG 1.44, Controlof the Processingand Use of Stainless Steelv RG 1.50, Controlof PreheatTemperature for Welding of Low-Alloy Steel

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New PlantActivities* Reviewing:

DC applicationsand SERs associatedwith the U.S. EPR and U.S. APWRdesigns-Adequacy of Long-Term Core Cooling

Approach for the ABWR-Reference COLAs for ABWR, ESBWR,U.SM-APWR, and U.S. EPR

- Subsequent COLAs for API00* Continuing to complete reviews ofavailablematerialpromptly

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License Renewal* Interim reviews performed for

Diablo Canyon and CrystalRiver* Will perform interim reviews of

Seabrook and Columbia in CY 2011

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Power Uprates* Will review the Turkey Point,NineMile Point, Grand Gulf, andMonticello Extended Power UprateApplications

Will review Supplements to NEDC-33173P-A, "Applicabilityof GEMethods to Extended OperatingDomains"

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Other OngoinglFutureActivities* SOARCA* Watts Bar 2* DigitalI&C* 10 CFR 50.46(b)e Small ModularReactorse Revision to the Construction Reactor

Oversight ProcessAssessmentProgram

o Blending of Low-Level RadioactiveWaste

e Emerging technical issues15


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cUIS.NRCUnited States Nuclear Regulatory CommissionProtectingPeople and theEnvironment

CurrentState of LicenseeEfforts to Transition to

NationalFire ProtectionAssociation (NFPA)Standard805

John.W. Stetkar


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10 CFR 50.48(c)" Issued in 2004, allows licensees toadopt and maintain a risk-informed,

performance-basedFire ProtectionProgram that meets therequirementsof NFPA Standard805 (2001 Edition)

* Alternative to 10 CFR 50.48(b) orthe plant-specific fire protectionlicense conditions

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June 25, 2010 SRM" The ACRS should conduct a review

and reportback to the Commissionon the currentstate of licenseeefforts to transition o NFPAStandard805" The review should includemethodologicaland other issues thatmay be impeding the transitionprocess, lessons learned from thepilot projects, and recommendationsto address any issues identified

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June 25, 2010 SRMi The review should determine

whether the level ofconservatism of themethodology is appropriateandwhether any adjustmentsshould be considered

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Pilot PlantLicense Amendments Shearon Harrisrequest submittedMay 2008; final safety evaluation

issued June 2010" Oconee request submitted May2008, revised April 2010; final

safety evaluation issued December2010

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ACRS Review of Transition"Consultantinterviewed industry

fire PRA practitionersand NRCstaff

"Reliability and PRASubcommittee m et in Novemberand December 2010

* Committee completed reviewduring February2011 meeting

February17, 2011 report21


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NUREGICR-6850; EPRI 1011989 Provides a sound technicalbasisfor the development of fire PRA

models and analyses to supportthe transition o NFPA 805

* Focused departures rom generalguidance will be necessary toaddress som e plan t-specificissues* Staff has accepted departures

with adequate technicaljustification22


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Baseline Fire PRA for Transition" Simplified models and boundingvalues often used for screening" Best estimate models and valuesused for refinements* Supports determination ofassurance tha t overall safety willbe maintainedunder risk-informedframework

Baseline fire PRA may retainconservative simplificationsandassumptions

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Post-TransitionApplications* Excessive PRA conservatism mayaffect quality of decisions forpost-transitionrisk-informed

applications Especially important for licenseeself-approved changes* Furtherrefinements of modelsand data needed for more realisticestimates of absolute risk andrelative contributors

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Analytical Conservatism Sourcese Arbitraryunilateraldecisions andinflexible guidance:not evident

from our reviews* Maturity of currentstate-of-the-

practicemethods: enhancedmethods in NUREGICR-6850; allPRA methods continue to evolve Analysts' choices regardingappliedPRA refinements: plant-specific

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Numerical Conservatism Sources-System atic bias in parametricvalues: conservatism m ay beintroducedby interpretationandapplicationof limited test data

* Large uncertainties:do notrepresent"conservatism" f theuncertaintiesaccuratelyaccountfor our currentstate of knowledge

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Quantificationof Uncertainties* Uncertaintiesare not quantified inthe pilot plant PRAs or in-progress"mature"studies* Uncertainties hould be quantified

consistently with currentmethodsand guidance* Understandingof perceived

conservatism and its sources* Characterization f post-transitionrisk-informed changes

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Overall PlantRisk Profile* Fire and internalevents PRAresults should be combined* Understandingof contributors o

overallplant risk profile* Post-transitionanalyses shouldcompare changes to risk fromfires and internalevents* Risk-informed decisions should

considercontext of proposedchange and PRA analyses

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Sequential Submittal Schedule* The staff,should considera firmschedule for sequentialsubmittalsof license amendment requests fortransitionconsistent with theindustry target of June 2012

- Fully incorporate essons learned frompilot projects- Time for industrypeer reviews and issue

resolutions- Improved technical quality of subsequentsubmittals- Improved staff reviews of plant-specifictechnicalissues

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Departures rom NUREGICR-6850" Industry peer reviews are effective,but schedules are limited bynumber of technically qualifiedindependent experts* Encourageactive engagement ofindustry senior technical review

group" Timely staff communications of

technicalpositions with genericapplicability30


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Fire Events Database" Careful treatment of most recentoperatingexperience"Explicitly account for plant-to-plant variabilityas a contributor

to uncertainties* Expedite data for "component-level" fire frequencies

" Caution that supplemental datam ay not significantlyreduceoverall fire risk estimates

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ElectricalCabinetFires* Typically most importantcontribution to fire risk" Propagation o nearby cables"Risk is. determined by location-

specific fire hazards, geom etry,cables, and circuits* Realistic analyses of fire ignition,

growth, detection, andsuppression are complex

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ElectricalCabinetFires"NUREGICR-6850 defines onegeneralcategory of "electricalcabinets"" Approach is retained n near-term

researchactivities" Cabinets should be divided intofunctional subgroups

" Facilitate mproved treatment offire ignition frequencies,potentialfire severities, and risk from plant-specific locations


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Interesting Observations Limited use of fire models forpost-ignitiongrowth, severity,andpropagation* Reliance on parametricvalues inNUREGICR-6850 and simplifiedempiricalcorrelations

* Limited test data to support moredetailed analyses (e.g.., heatrelease rates)

* Limited location-specificdetails34


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Interesting Observations* Multiple spurious operations ("hotshorts") are often important torisk, but were not identified as asignificant impediment toNFPA 805 transition* Comparableeffort is required orcable identification and circuitanalysis for compliance with10.CFR 50.48(b)

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US.NRCUnited States Nuclear Regulatory CommissionProtectingPeopleand theEnvironment

AP IO00 DesignCertificationAmendment,Reference COLA, and

Subsequent COLAHaroldB. Ray

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ACRS Reports Issued* APIO00 Design Certification

Amendment (DCA) - December 2010" APIO00 Long-Term Core Cooling -December 2010

* APIO00 Aircraft Impact AssessmentJanuary2011" Vogtle Units 3&4 Reference COLA -

January2011" V C. Summer Units 2&3 SubsequentCOLA - February2011


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18-Month Review Period* Both staff and app licantscommitted to supportive andresponsive interactionwith ACRS* Reference COLA initiallyBellefonte - Revised to Vogtle by

design center during review" Initiallyparallelreview processchanged to priority-based eview Scheduling flexibility by allconcerned essential to success

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DCA Review Process* Definition of changes is vital to effectiveACRS review Chapter-by-chapter eview of textrevisions makes change definition verydifficult where many changes are beingmade

" Late-submitted changes were reviewedindividually-not as chapter-by-chaptertext revisions

* Chapter-by-chapter taff reviews andACRS review of individualchanges wouldrequire more time

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ParallelDCA and COLA Reviews ,ACRS establishedreview priorities

placing DCA ahead of ReferenceCOLA and then Subsequent COLA* The design center greatlyfacilitatedmanagement of reviews

during the evolving process* COLAs requiredrevisions followingACRS review to reflect finalizedDCA

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Conclusions* Changes to certified designs

should be presented to ACRS asindividualchanges, rather hanrevisions to affected text on achapter-by-chapterbasis

* COLAs referencing an amendedcertified design should bereviewed after the DCA review iscompleted

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< U.S.NRCUnited States Nuclear Regulatory CommissionProtectingPeopleand theEnvironment

Comparisonof ISA andPRA for Fuel CycleFacilities

Michael T Ryan


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May 12, 2010 SRM* Directed the staff to prepare a

paper that compares ISAs forFCFs to PRA methods used forpower reactors

* Directed that the staff provide acopy to the ACRS for review

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ACRSIACNW Reports* January 14, 2002, ACNWrecommended that NRC move theISA process in the direction ofquantitativerisk assessment

* February22, 2010, ACRSrecommended that the staffcontinue to move FCF reviews inthe direction of risk-informedregulationsconsistent with otherAgency applications

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ISAIPRA ComparisonPaper Transmitted to the ACRS for

review on December 15, 2010* Concluded that ISAs were

acceptable for meeting10 CFR Part 70, but m ay needPRA approach to determ ine risksignificance of inspectionfindings

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Comparisonof ISA and PRAISA:" Used extensively in the chemical

industry" Conservativeanalysis* Identifies:

Accident sequencesHigh and intermediateconsequenceeventsItems Relied On ForSafetyManagement measures

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Comparison of ISA and PRA(cont.)

PRA:* Used extensively by the reactorindustry

* Realistic assessment* PRA also analyzes:- Human reliability- Dependencies- Relative risk importance of

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Comparison of ISA and PRA.(cont.)Advantages of PRA:" Ability to rank IROFS in terms of

risk importance* More rigorous treatment ofdependencies and human error* Ability to analyze complex

facilities" Provides an integratedriskperspective

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Conclusions* Staff's comparisonpaperprovided an

exposition of the advantagesanddisadvantagesof the use of ISA andPRA methods

ISAs, in combination with practicesrequiredby currentregulations,areadequate for licensing FCFs under10 CFR Part 70

* PRA is advantageousbecause itprovides a basis for prioritizationofsafety systems and maintenanceactivities 49


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Recommendation* The staff should continue todevelop and test the use of

focused PRA -like analyses tohelp assess the risk significanceof inspection findings in FCFs

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Path Forward0 Move ISA towards PRA for

complex facilities with highconsequences

* ACRS -willcontinue to interactwith the staff on cornerstonesfor the Fuel Cycle OversightProcess and choice of analyticmethods for implementation

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U.S.NRCUnited States Nuclear Regulatory CommissionProtectingPeople and theEnvironment

Use of Risk Insights toEnhance the SafetyFocus of Small Modular

ReactorReviewsDennis C. Bley

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Background* August 31, 2010 SRM

- Integraterisk insights and develop risk-informed (R-l) licensing review plans forSMRs- Build on SMR and NGNP review insights andNUREG-1860 to develop a new R-I licensingframework for the longer term

- Identify resolution strategies or policyissues* SECY-11-0024 Risk Insights in SMR reviews

- R-1 framework for iPWR reviews- R-I design-specific review plans for each iPWR- New R-1 regulatory ramework

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ProposedStaff Approach-iPWRs* Developed R-l review framework for

near-term iPWR designs* Develop design-specific review plans

- SRP tailored to each iPWR design

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ProposedStaff Approach Develop a longer term R-I

performance-based P-B) regulatoryframeworkpilot review iPWR design applicationcompare and contrast the proposedNGNP approach with NUREG-1860principlesCompare and contrastproposed LiquidMetal Reactor (LMR) approacheswithNUREG-1860 principlesConsolidate insights for R-I, P-Bframework recommendation

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2011 ACRS Letter" Draft framework is appropriate" Design-specific iPWR review plansis crucialstep" ConsiderPIRT-like processes to

guide development" Longer-term approach for licensereview of non-LWR SMRs is thelogicalextension of NUREG-1860

* Proposedpilot studies essential

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Additional Considerations


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* Lessons learned from recentdesign certificationreviews

* Risk-informed aspects ofanticipatedSMR applicationsrequire more complete PRAs

* Bound the external events for potentialsites

Application in remote and harshenvironments could requirespecializationof data and designassumptions

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Going Forward


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* Implementation of new frameworks" Novel designs of some SMRshighlightneed for criteriadefining

when experimental demonstration ofpredictedplant performance isneeded to provide confidence incomplex computer models

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AbbreviationsABWRACNWACRSAPWRAPIO00BWRCAPCFRCOLACYDACDCDCAECCSEDOEP REPRIESBWRFCFsGEiPWR

Advanced Boiling Water ReactorAdvisory Committee on Nuclear WasteAdvisory Committee on ReactorSafeguardsAdvanced Pressurized-waterReactorAdvanced Passive 1000Boiling Water ReactorContainmentAccident PressureCode of FederalRegulationsCombined License ApplicationCalendarYearDesignAcceptance CriteriaDesign CertificationDesign CertificationAmendmentEmergency Core Cooling SystemExecutive Director or OperationsEvolutionaryPower ReactorElectric Power Research InstituteEconomic Simplified Boiling WaterReactorFuel Cycle FacilitiesGeneralElectricIntegratedPressurizedWaterReactors

IROFsISAI&CLMRLWRNFPANGNPNRCNUREGICRPBPIRTPRARGR-ISECYSE RSMRSOARCASRMSRP

Items Relied on for SafetyIntegrated Safety AnalysisInstrumentation& ControlLiquid Metal Cooled ReactorLight Water ReactorNationalFire ProtectionAssociationNext GenerationNuclearPlantNuclear Regulatory CommissionNUREG Contractor eportPerformancebasedPhenomena IdentificationandRanking TablesProbabilisticRisk AssessmentRegulatory GuideRisk InformedSecretary of CommissionSafety Evaluation ReportSmall ModularReactorState-of-the-Art ReactorConsequence AnalysesStaff RequirementsMemorandumlMemorandaStandard Review Plan

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