U.S. LWR Sustainability Program - Energetics Meetings and Events

U.S. LWR Sustainability ProgramFY2010 Nuclear Energy University Programs WorkshopAugust 13-14, 2009Salt Lake City, UtahRonaldo SzilardDirector, INL, Nuclear Science & EngineeringDirector, Technical Integration Office, LWR Sustainability Program1

Reducing Carbon Emissions Requires All Technologies2030 Projected Annual CO 2Emissions (2008)(due to economic and population growth)Extrapolation to 2050CO 2Annual Emissions (2008)Technology EIA 2008 Reference* Target**Efficiency Load Growth ~ +1.05%/yr Load Growth ~ +0.75%/yrRenewables 55 GWe by 2030 100 GWe by 2030NuclearGeneration15 GWe by 2030 64 GWe by 2030Advanced CoalGenerationNo Heat RateImprovement for ExistingPlants40% New Plant Efficiencyby 2020–20301-3% Heat Rate Improvementfor 130 GWe Existing Plants46% New Plant Efficiencyby 2020; 49% in 2030CCS None Widely Deployed After 2020PHEVNone10% of New Light-DutyVehicle Sales by 2017; 33%by 2030DER< 0.1% of Base Load in20305% of Base Load in 2030President’s CO 2emission target*Energy Information Administration (EIA) Annual Energy Outlook (AEO)**PRISM-MERGE Analysis, EPRI, 200822

Supporting a Smart Energy MixNuclear generation is critical to:• Reduce greenhouse gases• Meet electricity demand• Secure energy supply• Maintain grid reliability• Curb increasing energy prices“We must harness thepower of nuclear energyon behalf of our efforts tocombat climate changeand to advanceopportunity for allpeople.“President Obama, April 5, 2009Prague, Czech Republic• Enabling Efficiency, PHEVs,DER via the Smart DistributionGrid• Enabling IntermittentRenewables via AdvancedTransmission Grids• Expanded Advanced LightWater Reactor Deployment• Advanced Coal Plants with CO 2Capture and Storage33

Nuclear is the Largest (75%) Generator ofCarbon Emission Free Electricity-Today• The President’s New Energy forAmerica plan seeks to reducegreenhouse gas emissions 80%by 2050.• Existing reactors reduce burden ofnew clean electricity that will needto come onlineOperating the existing reactors beyond 60 years isessential to achieve the President’s climate goals44

What is SUSTAINABILITY?R&D Enabling2029: first unit to reach 60-yrSafetyEconomicsPerformanceEnhancementsSafe, sustainable, reliable, long term operationof existing nuclear power plants• By 2030, U.S. domestic demand for electricityis projected to grow by 20%. During same time,global demand is expected to nearly double.• Cost to replace the current fleet exceeds$500B in addition to the capacity that will beadded as the U.S. builds new plants• 20 yr extension: 52 units granted;20 under review; 13 intend toreview; 19 unannounced5

Program Vision and GoalsVISIONGOALSExisting nuclear power plantswill continue to safely provideclean and affordable electricitybeyond current license periodsDevelop the understanding,tools, and processes to ensurecontinued long term safeoperation of existing nuclearpower plantsDevelop technical andoperational improvements thatcontribute to the economicviability of existing nuclearpower plants6

What have we done so far?• INL, EPRI examination of the issues associated with long termsafe and economical operation of existing and new plantshttp://nuclear.inl.gov/docs/papers-presentations/lwr_strategic_plan.pdf• DOE-NRC co-sponsored industry-wide workshop examiningresearch questions and opportunitieshttp://nuclear.energy.gov/pdfFiles/LifeAfter60WorkshopReport.pdf• R&D Program Planhttp://www.inl.govhttps://inlportal.inl.gov/portal/server.pt/gateway/PTARGS_0_2279_13610_0_0_18/LWR_sustainabilty_program_plan_rev%200.3.pdf7

R&D Program Objectives• Five high-priority objectivessupporting operating LWRs:Sustain highperformanceof reactorplantmaterialsTransition tostate-of-theartdigital I&CAdvances innuclear fuelImplementbroadspectrumworkforcedevelopmentImplementbroadspectrumimprovementsand design forsustainability8

Collaborative R&D ProgramScope• Nuclear Materials Aging and Degradation• Advanced LWR Fuel Development• Risk-Informed Safety MarginCharacterization• Advanced Instrumentation and ControlTechnologiesR&D Implementation• Coordinated by INL Technical Integration Office (TIO)• Coordinated with EPRI and NRC-RES• Implementation through broad-based Industry / National Laboratories /University collaboration / international partners9

Reactor Sustainability Research leveragesmodern scientific capabilities to develop--• A science based understanding of materials agingdegradation, e.g., loss of toughness, cracking, andcorrosion issues.• Improved modeling and analysis methods,including improved ability to quantify safetymargins, and address aging effects to understandhow safety margins change as plants age• New I&C systems and human/machine interfacecapabilities, including advanced plant monitoringcapabilities.• New long-life fuel designs using advancedmaterials to achieve substantial increases insafety margins and performance• Advanced predictive fuel modeling tools to helpeliminate fuel failures, achieve higher fuel burnups,and improve safety margins and performance1010

Success Requires the RightKind of Partnerships• A national program coordinated by INLTechnical Integration Office (TIO) –leveraging the best experts on the rightprojects• Implementation through broad-basedIndustry / National Laboratories /University collaboration / internationalpartners• Industry and government jointly define andfund R&D – cost sharing dependent ontype of research and timescale• Created with integrated collaborationamong industry, government anduniversities• Independent steering committee oversight,including EPRI, NRC-RES11

Reactor Sustainability Research Leverages Collaboration• Joins the unique capabilities of DOE national laboratorieswith universities and Electric Power Research Institute• Brings the best experts to the right research projects• Enables use of capabilities (instruments,laboratories, test reactors, hot cells, highperformance computing) necessary to understandbehavior of fuels and materials in harsh radioactive,thermal, and corrosive environments• Cost-sharing among DOE and industry R&Dappropriate to the types of research and thetimescales• International collaboration proposed with OECD’s HaldenReactor Project (Norway) and the Materials AgingInstitute (a consortia of EPRI, Japan’s TEPCO andFrance’s EDF)• Guided by an executive board comprised of nationallyrecognized experts from industry, universities. NRC andDOE.13 13

LWRS R&D Program Plan –5 year Budget Profile($M)$80$70$60$50$40$30I&CSafety MarginFuelsMaterials• Modest R&D costsharedfunding• Leverages largeindustry capitalinvestments$20$10$0FY-10 FY-11 FY-12 FY-13Large Pay Off1414

Reactor Sustainability Research in FY 2010 [$25M]• High fluence effects on reactor pressure vesselsteels and combined effects of irradiation andcorrosion on reactor core structures andcomponents• Assessment of concrete degradation, long-termcable performance, and buried pipe integrity• Prognostics related to material aging,degradation• Advanced welding and weld repair techniques• Advanced mechanistic understanding of fuelbehavior including interaction between fuelpellets and cladding materials• Advanced modeling to support safety analysis,mechanical models and irradiation designstudies of advanced composite cladding, andadvanced mathematical tools to support nuclearfuel calculations.FY 2010 Research Prioritiesand Planned Funding LevelsTotal $25M1515

Nuclear Materials Aging and Degradation• Research to develop the scientific basis for understanding laboratory andfield data on environmental degradation of materials, components, andstructures essential to safe and sustained nuclear plant operations• Four R&D areas havebeen identified:–Reactor Metals• Reactor Pressure Vessels• Core Internals• Secondary System• Weldments– Cables–Piping–ConcreteProactive MaterialsDegradation AssessmentMatrix16

Materials R&DGoals:• Develop a science based fundamental understanding of materials aging anddegradation• Address loss of toughness and corrosion issues• Support longer-term operation of existing reactors• Support licensing basis for extended operations• Support component life predictions for critical structures, systems, andcomponents.• Reduce the uncertainty in analytical predictions.• Provide insights for developing components with longer lifetimes.Specific planned activities:• Address high neutron radiation fluence effects on reactor metals including thereactor pressure vessel, core internals (stainless steels), and nuts and bolts (X-750); radiation induced swelling effects; and phase transformation of coreinternals.• Investigate crack initiation in nickel based alloys (steam generator tubing).• Investigate advanced welding and weld repair techniques.17

Aging and Degradation – R&D Areas18

9 topics for research starting in FY09• Consideration for prioritization included:– Degradation modes which are already occurring and will grow more severe duringextended lifetimes.– Degradation modes with little/no mechanistic understanding and in need of long-termresearch.– Degradation modes where work can follow-on or complement other national orinternational efforts without overlapping traditional industry or regulatory roles.– Areas where technical progress can be made in the near term.• Each of the following met at least one of the criteria for consideration:1. Mechanisms of IASCC-localized deformation2. Mechanisms of PWSCC3. High-fluence effects in RPV steels4. Weld-repair technology5. Phase instabilities in core internals under irradiation6. Concrete performance data7. Evaluation of swelling in stainless steel for PWR components8. Attenuation effects in RPV steels9. Cabling Aging19

Irradiation-assisted stress-corrosion cracking is beingobserved more frequently in LWR core components• Motivation: IASCC is being observed more frequently and in PWRcomponents. This trend will continue with increasing fluence andlifetime. The mechanisms are poorly understood.• Objective: Single variable experiments to help identify mechanismsof IASCC. Specific testing will include crack-growth rate tests, tensiletests hardness tests, and TEM analysis of irradiated.• Key Partners: ORNL, Univ. of Mich., EPRI, NRC• Other: this work will build off previous CIR, EPRI, and NEERprojects. Acquisition and testing of previously irradiated SSspecimens from the Bor-60 reactor. This task may also becollaborative and complement current proposed work (NRC andEPRI funded) to test existing specimens.20

Primary water stress-corrosion cracking is a problemin nickel-base alloys and will grow more severe• Motivation: PWSCC is poorly understood and of increasing concernfor plant reliability. Possible mechanisms include slip-dissolution,internal oxidation, and oxide rupture, although the exact mechanismis unknown.• Objective: examine PWSCC in common materials and determineunderlying mechanism of PWSCC• Key Partners: PNNL, ANL, EPRI, NRC• Other: this work will build off previous CIR, EPRI, and NRC effortsusing existing facilities and expertise at PNNL. This work will also becomplementary to tasks proposed under the Materials AgingInstitute.21

Life extension may double the fluence to RPVsteels and result in increased embrittlement• Motivation: Extending operation to 80y will result in a doubling of theneutron exposure and increased operating power level will furtherincrease the fluence to RPV steels.• Objective: Explore high fluence effects for pressure vessel steels,including “late blooming phases”, embrittlement, and data acquisitionmethods.• Key Partners: ORNL, UCSB, INL• Other: this work will leverage recent NRC work on RPVembrittlement mechanisms and provide an initial analysis of longtermneeds for reactor pressure vessels. Focus on analysis ofexisting specimens, including a high fluence capsule within thePalisades Nuclear Plant.22

Weld-repair techniques must be resistantto long-term degradation mechanisms• Motivation: Welding is already widely used for component repair.With extended lifetimes and increased repair frequency, these weldsmust be resistant to corrosion, irradiation, and other forms ofdegradation.• Objective: Evaluate residual stress control and mitigation techniquesfor SCC and technologies to avoid He-induced cracking.• Key Partners: ORNL, OSU, EPRI• Other: this work will build upon current and past experiences atORNL, EPRI, and OSU. The Edison Welding Institute may also be agood partner.23

Phase transformations in core components maycause embrittlement at higher fluences• Motivation: radiation-induced segregation and steel impurities maylead to the formation of second-phases at higher fluences, whichcould in turn lead to embrittlement. Phases such as gamma-prime,G, and sigma have already been observed in 316 SS baffle bolts.• Objective: Develop a model to predict phase transformations instainless steel components and generate validation data on existingirradiated components and samples.• Key Partners: ORNL, Univ. of Wisc., Univ. of Cal-Berkeley, andPNNL• Other: this predictive model will be extremely beneficial in predictingthe long-term behavior of stainless steel components.24

Concrete can suffer undesirable changeswith time due to environmental influences• Motivation: As concrete ages, changes in its properties will occur asa result of continuing microstructural changes (e.g., slow hydration,crystallization of amorphous constituents, and reactions betweencement paste and aggregates), as well as environmental influences.A key need is quality performance data from which to create modelsand analyze long-term needs• Objective: Collect, compile and analyze concrete performance inLWR applications• Key Partners: ORNL, Northwestern Univ., Univ. of Colorado• Other: this work is complementary to current EPRI and NRC work.Further, this will also leverage the Advanced Cement-BasedMaterials Program.25

Swelling of stainless steel may become moreprominent with increasing fluence• Motivation: Void swelling has recently been observed in PWR bafflebolts. With higher fluences expected over extended operations, thedegree of swelling may increase in some components.• Objective: Perform a comprehensive evaluation of the potential forswelling in LWR components over extended operations.• Key Partners: PNNL, ORNL, INL• Other: this work will extend previous work under EPRI, CIR, andother international programs.26

Neutron attenuation effects in RPV’s maydetermine embrittlement variations• Motivation: There is still controversy over how neutron attenuationinfluences variations in embrittlement through an RPV thickness.Attenuation and resulting variability may increase uncertainties athigher fluences.• Objective: Evaluate attenuation effects via improved modeling andanalysis of irradiated RPV steels.• Key Partners: ORNL and UCSB• Other: this is complementary to a recent IAEA effort and couldleverage international collaborations.27

Extended lifetimes could impact cabling performance• Motivation: Degradation of low and medium voltage cables willincrease over extended operating periods due to exposure to heatand water.• Objective: Evaluate long-term aging effects on cabling due toextended wetting, heat, and ionizing radiation.• Key Partners: SNL, ORNL, and Georgia Tech• Other: this work may help determine long-term replacement needsand drive other R/D for items such as fiber-optics and wirelesstechnology.28

Materials aging and degradation innuclear reactor systems is complexUnderstandingCombined EffectsCorrosion,Thermal Aging,EmbrittlementEnvironmentTemperatureIrradiationCorrosive Media(pH, ECP, flow rate)MaterialsStainless steelNi-alloysCast stainless steelLow-alloy steelZirconium alloysStressLoadFrequencyStateConstraintsMechanicalFailureStress-Corrosion Cracking29

Aging and Degradation – Time Table30

Advanced LWR Fuel Development• Advanced Fuels Vision for 2020:Improved Safety & Economics for LWRsAdvanced high performance fuels are an essential part of thesafe & economic operation of LWRs. The new fuels providehead-room for additional power upgrades and high burnuplimits.• Advanced Fuels Mission:• Improve the scientific knowledge basis for understanding andpredicting fundamental nuclear fuel and cladding behavior inLWRs• Develop high-performance, high burnup fuels with improvedsafety, cladding integrity, and nuclear fuel cycle economics.3131

Advanced LWR Fuel Development• Research to maintain and improve nuclear fuel designs toachieve improved economic performance while demonstratingsafety and performance margins. Develop high burn-up fuel withimproved cladding integrity as a primary fission product barrier• Three areas of research– Advanced Designs and Concepts– Advanced Science-based Analysis forfundamental mechanistic understanding– Advanced Tools• Two Time Horizons– 5-10: Support LTO decision in 2014-2019– 10-20: Support LTO operation beyond 203032

Advanced Fuels• Goals:• Develop advanced fuels to eliminate fuel failures, achieve higher fuel burn-upsand improve safety margins and performance• Develop advanced meso-scale fuel models to enable a predictive model forfission gas release• Develop a predictive tool for pellet-clad interactions• Develop new long-life fuel designs using advanced materials for fuel andcladding to achieve substantial increases in safety margins and performance• Improve the fundamental understanding of nuclear fuel and cladding behaviorunder extended burn-up conditions.• Specific planned activities:• Develop a model for fuel cracking at the mesoscale level with sufficientunderstanding to develop a predictive model for fission gas release.• Develop the understanding required for a predictive tool for pellet-cladinteractions.• Begin the development of new long-lived fuel designs with advanced fuel andcladding materials.33

Advanced Fuel Designs & ConceptsConsidered for Long-Term R&D• Advanced fuels– UOX variants (additive fuels, >5% U-235, enriched gadolinium)– Alternate fuels (UN, UC, hydride)– Novel designs (annular fuel, innovative shapes, liquid metal bond)– Dopants for PCI, thermal conductivity• Advanced Cladding– optimized next generation zirconium alloys–SiC• Advanced Coolant Chemistry–Nanofluids3434

Fuel Performance Modeling• Robust and efficient solvers• 3D coupling to 2D (and 1D) in the same code• Tight coupling between physics– contact and thermal expansion– fission gases in gap modify heat transfer• Resolve small time scale effects accurately– implicit to take long time steps during high burnup phase• Excellent serial and small parallel system performance– massively parallel not ignored35

Fuel Performance Known Issues• Details of fuel pellet / claddingmechanical interaction• Fuel thermomechanics• Fission gas formation /migration• Restructuring, constituentmigration• Damage – radiation, cracking,corrosion36

Fuels Performance Code Architecture• Requirements:– 3D (and 2D)– Massively parallel– Fully coupled and implicit– Advanced solution strategies (adaptivity, etc.)– Portable– Flexible physics interface– Flexible materials database• MOOSE: Multiphysics Object Oriented SimulationEnvironment• BISON: Brisk Implicit Simulation Of Nuclear-fuel37

Fuels Performance Code Platform• Plug-and-play modules– Simplified coupling• MOOSE Physics Interfaceconceals framework complexity• Framework provides core set ofcommon services• Solver Interface abstracts specificsolver implementations.– Common interface to linear andnon-linear solvers– More flexible• Utilize state-of-the-art linear andnon-linear solvers– Robust solvers are key for “easeof use”ThermalSolidPetscSNESPhysicsMOOSEContactFramework• Mesh• I/O• Element LibrarySolverInterfaceTrilinosNOXReactionDiffusion38

Capabilities300K element nonlinear heatconduction problem partitionedfor 1024 PEsh-refinement exampleMovie of pellet temperaturevs. time given constantvolumetric energy source39

Precracked pellet40

SiC Cladding DevelopmentLWR Sustainability Program Objective “develop high performance, high burnupnuclear fuels with improved safety, clad integrity, and fuel cycle economics”SiC Program Goal: design, develop and test a multilayered SiC clad fuel thatsignificantly increases fuel performance. Key characteristics include:• strength retention to at least 1500°C, appears to be DNB proof, and therefore canfacilitate power uprates of 30% or more.• minimal exothermic water reaction or H2 release during LOCA’s,• fully retains fission gases – no creep and FG retention to at least 5000 psi• composite layer solves ceramic “brittleness” problem• 100% production pressure test solves Weibull statistics issue• Can operate in LWR coolant for over 10 years with no appreciable corrosion– Zirc alloys embrittle after 5 years operation and are therefore limited by regulation to 62 gwd/t• When coupled with increased U235 loading, can double the burnup to 100 gwd/t• Very hard, resists fretting and debris failure, further reduction in operational failures4141

What is SiC Triplex Cladding ?• SiC Triplex Cladding– Monolithic dense SiC inner layer (12-15 mils)– SiC/SiC composite intermediate layer (12-15 mils)– Outer CVD SiC barrier layer (3-5 mils)FILAMENT WINDINGMONOLITHICDENSE SiCTUBEMATRIX DENSIFICATIONBARRIERLAYERSiC FIBERTOW“TOW”(500-1000 FIBERS)SiC f /SiCCOMPOSITE LAYERCeramic Tubular Products LLC42

Performance Comparison of Zircaloy fuel rods vs SiC Rods in TMI• Zircaloy Cladding (used in TMI reactor)– Tubes ballooned at 900°C after 2 hours– Coolant blockage at approx 1200°C– Exothermic reaction of zirc with H 2 O• Silicon carbide composite cladding– Retains strength to >1500°C– No ballooning with minimal reaction– Very little damage – gas only• Conclusions– Could have avoided $3B cleanup– Could have saved a $2B asset– Would have provided more responsetime for operatorsIncreased safety leads to greater public acceptance of Nuclear43

Advanced LWR Fuel Development – Time Table44

Advanced Instrumentation and Control Technologies• Research to improve inspection and monitoring technologies, including detailedstrategies for managing Instrumentation & Control (I&C) system upgrades.Develop, implement, and evaluate prognostic monitoring approaches for bothnon-safety-related and safety-related systems• Four Proposed Technical Projects:– Centralized On-line Monitoring for Critical SSCsInformation technology and degradation models/cases toenable real time automatic statistical analysis, patternrecognition, and criteria to diagnose degraded conditionsand predict remaining useful life of SSCs– New I&C and HSI Capabilities and ArchitectureApproach to achieve life cycle renewal of information & controlcapabilities needed to continue to operate safely and more efficiently– Life-cycle NDE Information AssessmentEnhancement of measurement (NDE+), data capture andstorage for NPP primary systems to support forthcomingdiagnostic and prognostic models– Maintaining the Licensing and Design BasisTacit knowledge capture and transfer enhanced by 3-Dvirtual models where beneficial45

Advanced Instrumentation and Control• Goals:• Develop new I&C systems and human/machine interface capabilitiesincluding advanced plant monitoring capabilities• Support power up-rates and plant efficiency improvements• Support longer-term operation• Reduce plant staffing and facilitate centralized monitoring of nuclearfleet status and performance• Develop advanced condition monitoring and prognostics technologiesto understand and measure the aging of systems, structures, andcomponents of nuclear power plants.• Specific planned activities:• Develop plant control and monitoring systems to improve plantefficiency, facilitate power uprates and enable remote monitoring andsupport.46

I&C Technologies Time Table47

Risk-Informed Safety Margin Characterization• Research to fully understand and incorporate singleeffects and integral testing results into both deterministicand risk-informed safety margin characterizations• Three R&D Areas Identified:– Integrated Risk Modelingaggregation of all hazards, declarativemodeling, treatment of uncertainties– Enhanced technology integrationaging effects, equipment condition,visualization of results, real time successcriteria– Real time analysis capability for operationalrisk management decision-makingadvanced quantification techniques, plant dataconnectivity48

Risk-Informed Safety Margin Characterization (RISMC)Goals:• Develop improved modeling and analysis methods including uncertaintyquantification to enhance industry’s ability to accurately predict safety margins• Address aging effects to understand how safety margins change with aging plants• Support power up-rates• Combine risk-informed, performance-based methodologies with fundamentalscientific understanding of critical phenomenological conditions and deterministicpredictions of nuclear plant performance.Specific planned activities:• Develop a risk-informed simulation-driven methodology to guide LWR safetysystem analysis and uncertainty quantification.• Enhance the deterministic safety analysis capability to simulate plant dynamicsand compute safety margin.• Begin the development of the next generation of probabilistic risk analysis.• Incorporate passive structures, systems and components into a probabilisticsafety analysis at one plant type.49

Risk-Informed Safety Margin Characterization (RISMC)• Concept pursued as a “seed” pathway in the LWR Sustainability Program• The main theme of the RISMC activity is the reduction of technical, programmaticand regulatory uncertainties that complicate decision-making on sustainability?LoadCapacityPotentialDevelopmentsPower uprate,Increasing Fuel burnupsAgingHigher frequencies of IEsNew IEs and sequencesCascading failuresVulnerability (surprise) Search for failure (new wayof doing experiments and analysis)50

Nuclear Systems Safety AnalysisWhat ArePossibleAccidents?How Do TheyOccur?DSA: Deterministic Safety AnalysisExperiments,SimulationsImagination,Precaution,Operating ExperienceHow OftenThey Occur?PRA: Probabilistic Risk AnalysisWhat AreConsequences?How plant aging affects 51these four questions?

Integrating Probabilistic and DeterministicApproaches in Safety AnalysisThe strategic objectives of the RISMC R&D pathway are to bring togetherrisk-informed, performance-based methodologies with fundamentalscientific understanding of critical phenomenological conditions anddeterministic predictions of nuclear power plant performance, leading to anintegrated characterization of plant safety that support optimization ofnuclear safety, plant performance, and long-term asset management.The main theme of the RISMC R&D activity is the reductionof technical, programmatic and regulatory uncertainties thatcomplicate decision-making on SustainabilityRISMCScientific foundations and tools to effectivelymanage cost, schedule and technical risks52

RISMC-based ProcessFormal, Science-Based Process for “Safety Case” Development, Evaluation, and ResolutionQuantitative PIRTUncertainty QuantificationSensitivity AnalysisValidationVerificationSoftware Quality AssuranceR753

RISMC ProcessRequirementsR7 in RISMC ProcessAccident ScenarioAdequacy of plant discretemodel, model fidelity level,and closure data supportYesPlant DiscreteModeling (Meshing)Multi-physicsPlant ModelSafety Margin(with UQ)UncertaintyAcceptable?●●●Single-PhysicsNoCore NeutronicsModel●●●LocalParametersThermal-HydraulicsSystem ModelCoarse-Grain (SGS)Closure LawsUncertaintyQuantificationModel FidelitySelectionIdentify weakness? Discrete Model? Model Fidelity? Closure DataUse SensitivityAnalysis (SA)AdvancedDiagnosticsIE and SEExperimentsCorrelationsData MiningDatabasesData ManagementHPC-GeneratedHigh-FidelityIE and SE“Data”54

RISMC Project Hierarchy and Information FlowDecisionModelRISMC BasicsRISMC Applications(Case Study)Formulation ofSafety CaseProcesses,PerformanceMethods& ToolsR7 (Loads)Advanced DSAPrevention AnalysisAdvancedIntegrated AnalysisPRACapacitiesRisk, Reliability,Availability,Maintainability,Inspectability(“Advanced I&C”)Data,PhysicsModelsEvidence-Based Assessment of Safety Margins at the Component LevelIdentification of hithertoneglectedpassive SSCsAging and Degradation Models55

Building Industry’s ConfidenceEnabling Life Extension SuccessConfidenceLife extension implementation$$$ refurbishmentLife extension licensing$$$ commitmentBenefits to Gen III, Gen IVParadigm ShiftRefined and qualifiedprocess and tools.Robust approach tosafety margins and howto best utilize it.High confidence in the RISMC processand tools for quantification andmanagement of safety margin. Regulatoryacceptance for RISMC case studies.Life extensionUtility decisionEstablish confidence that the full set of sustainabilitycriticaldata and tools required for the final “safety case”can be developed within available time and resourcesLWRS R&D generates sufficient amount of “sustainability-critical” data,methods and tools, establishes a RISMC process and shows on selectedcase studies that sustainability “safety case” formulation is viable.2010 2015 2020 202556Time

Advanced DSA: R7• Project: “Development of a Next-Generation Production Code forNuclear Reactor System Analysis and Safety Margin Quantification”‣ R7 – Building on INL’s legacy in safety analysis i.e. RELAP5code‣ Next Generation – New idea and new technology to carry the Labforward and enable the paradigm shift in safety analysis.‣ Production Code – Oriented to engineering practice, with avalidation pedigree so it can be used to aid in reactor safetydecisions.‣ System Analysis – All of the relevant physics with their widelyvarying length scales and time scales will be simulated.‣ Safety Margin Quantification – The key in safety decisionmaking is to know how far you are from danger and howconfident are you that you know the distance.57

Multi-disciplinary Approach to Multi-Physics ProblemDefining New Frontiers in CSE, HPCStructuralMechanicsCoreNeutronics●●●e.g., Coolant Chemistry,FPTPlantI&CActiveComponentsSensitivityAnalysis,UncertaintyQuantificationMulti-physics,Multi-fidelityAlgorithmsAdvancedSolutionMethods(Solvers)ComputableMeshingGoverning Multi-PhysicsModelsFuelPerformancePassiveComponentsThermalHydraulicsHeterogeneous SystemFluids,MaterialsPropertiesComplexityHeterogeneous SystemComponents, Controls, ConnectivityMulti-FidelityMultiplePhysics●●●e.g., HFPump,Valve, etc.HPC: HighPerformanceComputingPipe, Tanks,etc.●●●Computational MethodsComputational Infrastructure(advanced CSE)Challenge: code “DNA” … architectural design to accommodateapplication requirements and code development requirements58

R7 Project– To effectively support safety analysis, R7 must possess ability to select modelwith fidelity level appropriate for safety decision under consideration– With the ultimate goal of uncertainty reduction (not only UQ), developmentand V&V of models, methods and code must be guided by QPIRT processsupported by sensitivity analysis machinery• Started October 2008 as FY09 Laboratory-Directed R&D (LDRD) Team across Departments (RPDA, TSSA), Divisions (NSE, NRRS, CAMS) Work in collaboration with TAMU, Oregon State, MIT, NCSU, Utah State• Leveraged on capabilities in Thermal hydraulics, Neutronics, Fuels & Materials,advances in Computational Science, and expertise in System Analysisand Reactor Safety – all under one roof• R7 Workshop: “Verification and Validation, Sensitivity Analysis, and UncertaintyQuantification of a Next Generation System Safety Analysis Code”(January 12-14, 2009)59

Adaptive Modeling to Effectively Support Safety AnalysisSystem Complexity(Dimensions,Components,Heterogeneity)CGM- and AMR-basedSystem AnalysisVehicleSystem AnalysisReal-timeSimulatorsSimplified Plant,“Detail” ProcessesSeparate EffectsCGM – Coarse-Grain ModelingAMR – Adaptive Model RefinementOther Programsat DOEComputing Expenses ?? Validation Adequacy“Firstprinciples”[CFD-RANS]System codesPhysics ModelingSimplification“Far better an approximate answer to the right question, than the exact answer tothe wrong question, which can always be made precise. ”, J. W. Tukey (1915-2000)60

RISMC Pathway Composition12Technical Management, Integration, Assessments, and Communications1.1Planning, Coordination and IntegrationDevelopment of RISMC Framework2.1Formulation of Margin-Based Safety Case Framework2.2RISMC Working GroupDevelopment (demonstration and validation) of RISMC-Enabling Methods and Tools33.13.23.3Next Generation Code for Mechanistic Simulation of Nuclear Power Plant’s Safety-Significant Transients and AccidentsNext-Generation Probabilistic Risk AnalysisNext-Generation Prevention AnalysisDevelopment of RISMC Inputs44.14.24.34.44.5Enhanced Technology Integration ScopingIncorporation of Passive SSCs Into Risk ModelIntegrate Technical Results form Materials PathwayIntegrate Technical Results form Fuels PathwayIntegrate Technical Results form I&C Pathway61

RISMC Time Table62

Examples of Case Study Candidates Pressurized Thermal Shock (PTS)ORNL Large-break LOCA (design basis requirements)Utility Steam Generator Tube Rupture (SGTR)NRC PWR shutdown operation during mid-loop conditionsEPRI Advanced Fuels with Ceramic CladdingVendor Advanced sensors and characterization technologies (NDE)PNNL63

Summary• USG recognizes the important role of US nuclearpower plants• New nuclear plants are not expected to come on-lineto compensate for 60 year retirements• Continued long-term operation of existing nuclearplants is key to future emission-free generation• Research is necessary to establish basis for long-termoperation of existing nuclear plants– Be driven by industry needs– Answer questions on systems, structures andcomponents aging and reliability issues associated withlong-term operation– Leverage the resources of industry, national laboratory,and university system– Continue to improve LWR technology64