Mike burke besac 7 09 by 6m8MyeLb

VIEWS: 4 PAGES: 39

									    “Materials’ Issues and Research Needs for
    Electricity Generating Light Water Reactor
    Sustainability : An Industrial Perspective”

                       Mike Burke
            Manager Materials Center of Excellence
              Westinghouse Electric Company


                   DoE BES Advisory Committee
                          July 9th 2009
                         N. Bethesda Md.




1
Growth of Nuclear Power Generating Capacity
LWR Sustainability and New Plant Installations
                                    How will we keep
                                    the older reactors
                                    operating ?

                                    What technologies
                                    are needed now to
                                    support the planned
                                    new builds ?

                                    What technologies
                                    should be put in
                                    place to provide for
                                    next generation
                                    plants ?


2
    Materials Implications of the Upcoming
    Demand for Nuclear Power

                    Near Term             Intermediate Term           Long Term
    Plant Options   Relicence Existing    Relicence Existing Gen      Relicence Existing Gen III+ Plants
                    Gen III Plants        III Plants                  (80 years)
                    (40, 60 years)        (60, 80 years)              Build New Gen IV Plants
                                          Build New Gen III+
                                          Plants


    Reactor         Existing BWR and      Advanced BWR and            Improved BWR and PWR plants,
    Technologies    PWR plants            PWR plants                  Supercritical Water Reactor, Gas
                                                                      Cooled Reactors, Lead and Sodium
                                                                      Cooled Reactors


    Materials       Understand existing   Extended understanding      Material properties in “extended”
    Technology      plant materials.      of traditional materials    conditions (temperature,
    Implications    Quantify time         Validation of “improved     environment, very long time etc.)
                    dependent materials   materials” used to repair
                    properties            Gen III reactors




3
    Issues for Materials Usage in Operating and
    New Plants
    ●   Plants are designed for long lives
    ●   No material is “Impervium”
    ●   Degradation mechanisms are generally known
    ●   Materials response must be predictable

    ● Quantitative precise prediction of materials’ response to
      service is needed  linear models
    ● Discrimination between material variants is needed 
      need to quantitatively understand the effects of the major
      variables

    ● Technologies for inspection, monitoring and repair will
      always be required



4
    Materials Technology Support for Power Generating
    Reactor Fleet Sustainability
    Industrial Solution               Current Issues
    Application specific empirical    No integrated models for long time behaviors
       models (PWR, BWR Fast          Limited range of accuracy
       Reactor)                       Limited range of extrapolation – late blooming phases ?
    Specific alloy performance        Processing and chemistry variable behavior should be
       data                              understood
    Bounding data for material        Excessive conservativism in some cases ?
       classes
    Sparse database                   Conservativism, inability to differentiate between material
    Materials repair and mitigation   Limited acceptance of alternative technologies, need to
       processes (Proof of               undergo stringent validation before implementation is
       performance data)                 allowed
    In place NDE methods and          Limited acceptance of new technologies, significant
        performance monitoring           validation and qualification efforts needed for new
                                         technologies

      Recognize that nuclear industry is safety driven, changes
      and data must be validated – and it’s difficult to do !


5
    Materials Technology Enhancement Opportunities to Support
    for Power Generating Reactor Fleet Sustainability
                                      Technology
                                        Enhancement
    Industrial Solution
                                      Improve model accuracy in
    Application specific empirical       real (linear) time and
       models (PWR, BWR Fast             extended service
       Reactor)                          prediction capability
    Specific alloy performance
                                      Discriminate heat to heat
       data
                                         and process dependent
    Bounding data for material           property variability
       classes
    Sparse database                   Improve confidence in
                                         predictions
    Materials repair and mitigation
       processes (Proof of            Ready to implement
       performance data)                 effective repair and
    In place NDE methods and             mitigation technologies
        performance monitoring        More effective plan
                                         operations and
                                         maintenance




6
    Basic Science Opportunities to Support for Power
    Generating Reactor Fleet Sustainability
                                      Technology
                                        Enhancement                Basic Science Support
    Industrial Solution
                                      Improve model accuracy in
    Application specific empirical                                 Integrated quantitative models of
                                         real (linear) time and        materials behavior and
       models (PWR, BWR Fast             extended service              degradation
       Reactor)                          prediction capability
                                                                   Understanding of metallurgical effects
    Specific alloy performance                                        in alloy behavior (Chemistry,
                                      Discriminate heat to heat
       data                                                           microstructure effects)
                                         and process dependent
    Bounding data for material           property variability      Property variation with respect to
       classes                                                        material variants
    Sparse database                   Improve confidence in        Extension of materials property
                                         predictions                  database
    Materials repair and mitigation
       processes (Proof of            Ready to implement           New materials repair, coating and
       performance data)                                             surfacing methodologies
                                         effective repair and
                                         mitigation technologies   Advanced sensing and monitoring
    In place NDE methods and
                                                                      technologies – application to
        performance monitoring        More effective plan             “materials condition”
                                         operations and
                                         maintenance




7
    Ground Rules for Materials’ Selections for
    Operating and Planned Nuclear Power Plants
    ● Industry has addressed issues with today’s aging plants
       – NRC GALL (Generic Aging lessons Learned) Report
       – NEI Materials Initiative 03-08 – “Guideline for the Management of
         Materials Issues”
    ● Near Term Commercial Plants will be built to already established design
      practices
       – Materials selection often based on experience
       – System design calls for code verified data (materials properties)
       – Long term and irradiated materials’ properties are only available for
         established materials
    ● Next Generation plants must be built to the same safety concerns
       – Assurance of material properties ?
       – Aging response ?
       – More potential for (need for ?) new materials
       Consider materials technology needs for these 3 sets of plants




8
    Reactor Materials for Existing and Near Term Plants

    Ferritic Low      Reactor, Pressurizer, and Steam Generator Pressure
    Alloy steels      Vessels, Steam Generator Tube Sheet, Large Bore
                      Piping
    Ni Base Alloys    RVH Penetrations, SG Tubing, Piping (D-M) Welds,
                      Corrosion Resistant Cladding (by Weld Deposits)
                      Fuel Assembly and Spring Applications
    Stainless         Reactor Internals (Barrel Plates, Formers, Bolts)
    Steels            Support Plates, Control Rods, Piping, Corrosion
                      Resistant Cladding (by Weld Deposits)
    Zr Alloys         Fuel Cladding, Fuel Grids, In Core Instrumentation
                      Tubing

                Assembly by Pinning, Welding and Bolting



9
     Key Driver for Existing Plant Technology Needs
     = Plant Relicensing Process
     ● Plants are Licensed to Operate by the NRC
     ● Licenses are held on a 20 year basis
     ● 2009-2013 Upcoming License Renewals Period for many
       US PWR Reactors
     ● Relicensing Application Must be Supported by Technical
       Data Demonstrating Safe Operating Capability
     ● Key Element of Relicensing plan is the Proposed Plant
       Specific, Inspection and Evaluation Program
     •Quantitative data are required to properly disposition
     inspection findings
     •Accurate data are needed to avoid excessively
     conservative reaction


10
      Materials Issues For Existing Plants

     Ferritic Low Alloy   Irradiation Embrittlement Updated PTS Rules,
     steels               Resistance of Head Penetrations to SCC,
                          Fatigue of Piping
     Ni Base Alloys       SCC of Head Penetration Welds, SCC of Dissimilar Metal Welds in RV
                          and Pressurizer Nozzles,
                          SCC in SG Tubing, Protection of SG Tube Sheets,
     Stainless Steels     Internals Hardening and Embrittlement,
                          SCC of baffle Bolts, SCC of Welded Internals,
                          Mitigation of Piping Welds,
                          Thermal and Irradiation Embrittlement of CASS
     Zr Alloys            Fuel Rod Leakage, Integrity of Welds,
                          New Materials with Reduced Oxidation/Hydriding
                          CRUD Formation Mitigation

           The Nuclear Power Generation Industry Currently Manages All of
            These Issues to Keep Plants Operating at 90% of Capacity Factor
           Technology Developments Must Be Able to Discriminate Between
               Materials Variants at These Levels for Long Time Behaviors



11
     Materials Issues For Existing Plants
     ● Key issue for structural materials is to validate materials survivability to
       long life (>60 years)
     ● Key issue for fuel related materials is to withstand higher burnup
     ● “improved materials/confidence in materials” will be acceptable for 2-3x
       lifetime increase - compare to data scatter on log-log plot !


      Consider examples of current technology
         Current solution – Enhancement Gap - Basic Science Opportunity
      Identify basic science opportunities that may improve materials
       performance and/or confidence in materials performance
         Pressure Vessel Materials, Internals Materials, Ni alloys (piping, tubing), Zr
          alloys (core structures, cladding)




12
       Materials Issues for Existing Plants –
       Evaluation of Pressure Vessel Materials

     • Ferritic steels become embrittled in
     neutron and thermal environments
     • These changes are manifested in :
          Reduction in the toughness during
         ductile fracture
          Tendency to brittle fracture at onsets
         at increasing temperatures

     Plant operations monitor vessel materials
     for embrittlement and feedback properties
     into analyses to support operations
          Surveillance capsule programs for
          vessels
           License requirement - Pressurized
          Thermal Shock (PTS)                        Acceleration Factor of Capsule
          Operational Limitations – heat           Samples Leads Real Life Material
          up/cool down “curves”




13
 Reactor Containment Vessel Monitoring
 Against “Pressure Vessel Embrittlement”




                                 Key Region
                                 for Surveillance
                                 Programs
                                 so called
                                 “Beltline”




14
     Typical Surveillance Capsule Locations
                                Usually 8 capsules per vessel




                     Capsules are locate in the highest intensity
                     region, attached to the backside of the
                     core barrel

15
     Fracture Behavior of Pressure Vessel Steels
     Continuing Issues and Research Needs
     ● The industry has a large inventory of tested materials –
       re-irradiations can be readily performed
     ● Extrapolation of embrittlement curves to higher dpa for >60
       year life is a current issue
     ● Resolution of fast reactor data and extrapolation of
       surveillance capsule data to highest fluences
     ● Complete understanding of chemical effects and cross-
       interactions
     ● Full utilization of fracture toughness methodologies (c.f.
       Impact data)
     ● Projections to new steels etc.




16
     Technology Enhancement and Basic Science
     Opportunities for Pressure Vessel Materials
                                      Technology
     Industrial Solution                Enhancement               Basic Science Support
     Embrittlement trends available   Improve model accuracy in Quantitative (Linear) mechanistic
       for industry wide database        real (linear) time and    based models
                                         extended service       Understanding of metallurgical effects
     Extensive chemistry
                                         prediction capability     in alloy behavior (Chemistry,
        information available –                                    microstructure effects)
        data for wrought alloys and
        weld                          Discriminate heat to heat Property variation with respect to
                                         and process dependent     material variants – and processing
     Conflict between thermal and                                  induced variations
                                         property variability
        fast reactor data –flux                                 Mechanistic aspects of degradation :
        effects ?                                                  microstructure  properties
                                      Improve confidence in
     Extrapolation to long times                               Resolve late blooming phases –
                                         predictions
         effects of late blooming                                  “optimally conservative”
         phases                                                    predictions to longer lives
     In place surveillance capsule    More effective plan       Consider other sensing technologies
         program                         operations and            for pressure vessels
                                         maintenance




17
     Materials Issues for Existing Plants – Evaluation
     of Vessel Internals Materials
     ● Recognize degradation has occurred and effects of degradation are
       generically known
     ● Plant specific materials extraction and sampling is not feasible
     ● Some opportunities to assess materials from plants do occur
     ● Testing programs are in place e.g. Halden
     ● Testing programs are sparse and expensive to perform
        – In-core testing
        – Hot Cell testing of pre-irradiated materials (in environment)
        – Accelerated irradiation exposures and evaluation/characterizations
     ● Data on exposed materials has been built into advanced modeling
       systems
        – Generic Materials Degradation Rules
        – Systematic Analyses
        – Key Materials Properties
     ● Allows identification of key issues/areas
     ● Support to I&E Guidelines and relicense applications




18
     Materials Degradation Modeling for
     Reactor Internals Applications
     Apply modern simulation capabilities to a systematic analysis of all
       components in plant internals)
        – Consider failure under 8 Mechanism
        Thermal Embrittlement       IASCC Wear        Void Swelling
        Irradiation Embrittlement   SCC    Fatigue    Irradiation Creep/Relaxation

        – Calculate materials degradation and continuing response with
          respect to time, fluence temperature etc.
        – Model can currently provide self consistent, semiquantitative
          assessments of failures
             – Allows identification of Classify Component/Mechanism Pairs
               and Determine Quantitative Rankings for Each Mechanism…
             – … Use such rankings as ordered priority to develop inspect and
               evaluate of components strategy (“Waterfall Charts”)




19
     Materials’ Constitutive Modeling for Quantitative
     Assessment of Reactor Internals Degradation
                Loads, Temperatures,
             Environments, Neutron Flux                               Aged Materials
                                                                         Condition
                              Local Stresses
                                                    Time                Microstructure
                                and Strains         step         Defect Content, Segregation
     Initial Materials
         Condition
       Microstructure
Defect Content, Segregation


                               Redefine Local Stresses       New Material Response
                                     and Strains           “Modified Compliance matrices”



 FEA Modeling allows iterative reassessments               New/Modified Failure Criteria
   of local conditions – Can model materials
  degradation and assess potential for failure
under local conditions of materials degradation




20
     Materials Degradation Modeling for Reactor
     Internals Applications – Materials Availability
      Materials should reflect behavior in
      LWR situation – effects of accelerated
      aging ?
      Materials available after high dose -
      from decommisioned plants (or
      replaced internals ?)
      Sufficient fluence and local heating to
      predict behavior to long plant life ?
      Properties :
          Stress/Strain Behavior
          Fracture Toughness
          Stress Corrosion Cracking
      Test Environment (with or without
      neutrons)
          Hot Cell Testing
          Test Reactor Testing
                                                    Schematic Extraction
                                                Locations for RVI Test Material



21
     Materials Degradation Modeling for
     Reactor Internals Applications
     Reactor Structural        Effects of Irradiation on Stainless
     Internals are made from   Steels
     Stainless Steels              Hardening & Loss of Ductility
                                   Stress Corrosion Cracking
                                   Irradiation Induced Creep




          Both Compliance and Failure Data Must be
            Developed to Support these Analyses

22
     An example of Automated Constitutive Modeling
     IASCC Susceptibility of Reactor Internals (Bolted Baffle Plates)



                                               IASCC Susceptibility
                                                 • Blue : No Concern
                                                 • Yellow : Minimal Concern
                                                 • Red > Increase Concern




      Constitutive Modeling of Materials Degradation Provides Rapid
      Screening of Large Systems and Precise Analysis of Highly Localized
      Systems but…
      Provides direct comparison of locations and components
      Identifies the most likely locations for failure…
      …Primary locations for inspections


23
     Application of Results of Materials Modeling -
     Waterfall Approach to Inspection Prioritization

     Baffle –Former     IASCC                           Goal
          Bolts
                                                          Aging management strategy based on a
                                       Baffle Plates
     Baffle –Edge
                                                          prioritized grouping of the expected
         Bolts        Relative                            degradation mechanisms by manifestation.
                      Ranking          Former Plates

     Barrel –Former    From
          Bolts       Modeling         Core Barrel –
                                       Lower, Upper
                                                           Task
     Lower Support
     Column Bolts                      Thermal Shield          Group components in a manner
              Other Components – AMS                           that will facilitate a common AMS
               Unnecessary for IASCC
                                                               for all items in group.


                      Waterfall
                       A stream of actions that will provide an appropriate aging
                       management strategy for multiple degradation mechanisms.


24
     Materials Degradation Modeling for Reactor
     Internals Applications – Data Availability
                  Test Data Available for CASS used
                         in Reactor Internals




               Sparse database prevents full utilization of modeling




25
     Technology Enhancement and Basic Science
     Opportunities for Reactor Internals Materials
                                               Technology
     Industrial Solution                         Enhancement                Basic Science Support
                                               Improve model accuracy in    More extensive property database –
     Data for 316SS, 304SS and 316SS
         at 050dpa                               real (linear) time and       compliance and failure criteria vs dpa
                                                  extended service          Understanding of aged (and corroded
     Tensile and hardness data available
                                                  prediction capability        surface) materials response to
     Fracture Toughness and SCC                                                continuing long time exposure
         (particularly IASCC) are still to     Discriminate heat to heat    More precise quantitative data –
         be developed                             and process dependent        understanding of scatter
     Existing data are for old vintage            property variability      Understanding of metallurgical effects in
         plants (old vintage materials)                                        alloy behavior (chemistry, microstructure
     Knowledge gaps with respect to            Improve confidence in           effects)
        very high fluence behavior (but           predictions               Property variation with respect to material
        data shows plateaus ?)                                                  and processing variants
     Good service at already high dpa          Ready to implement           High dose behavior – reality of swelling
                                                                                effects
     Bolting replacement                          effective repair and
                                                  mitigation technologies   Welding technology for repair of irradiated
     Existing visual and ultrasonic                                            materials
         inspection capabilities for in-situ   More effective plan          Coating and (re) surfacing technologies ?
         inspection of components                 operations and
                                                                            Advanced sensing and monitoring
                                                  maintenance                  technologies – application to “materials
                                                                               condition




26
     LWR Materials Applications & Degradation
     Mechanism Issues

                 Applications                            Degradation
                                                         Mechanisms
     Low Alloy   Reactor Pressure Vessel, Pressurizer,   Embrittlement, Fatigue
     Steel       Piping
     Stainless   Reactor (core support and flow          Embrittlement, SCC, IASCC, Fatigue,
     Steel       direction) internals, Control rods,     Stress Relaxation, Wear,
                 Pressurizer internals, Clad on Low      Errosion/corrosion
                 Alloy Steel, Piping
     Zr Alloys   Fuel Cladding, Fuel skeletons           Corrosion, Embrittlement, Wear,
                                                         Irradiation Growth, Pellet Clad
                                                         Interactions
     UO2         Fuel,                                   Pellet Densification/ Growth, Fission
                                                         Gas Release
     Ni Alloys   RPV Head penetrations, Nozzles,         PWSCC, Secondary side SCC
                 Steam Generator Tubing, Low Alloy
                 Steel Cladding
     Specialty   Control rods, control drives, wear      Swelling, Metal/ceramic interactions,
     Materials   surfaces                                Wear, Corrosion, …….




27
     Technology Enhancement and Basic Science
     Opportunities for Corrosion Resistant Materials
                                       Technology
     Industrial Solution                 Enhancement                Basic Science Support
                                       Improve model accuracy in
     Stainless steels, (alloy 600)                                  Quantification of corrosion and SCC
        Alloy 690 used for primary        real (linear) time and      data
        and secondary side                extended service
                                          prediction capability     Understanding of metallurgical effects
        corrosion resistance                                           on corrosion and SCC properties
     Long term data and plant          Discriminate heat to heat       (Chemistry, homogeneity
        experience based on               and process dependent        microstructure effects)
        vintage materials                 property variability      Property variation with respect to
     Crack initiation and crack                                        material variants and
        propagation data being         Improve confidence in           new/replacement parts’ materials
        developed for some alloys         predictions
     Materials repair and mitigation                                More effective materials repair, coating
        processes based on             Ready to implement              and surfacing techniques
        welding are available             effective repair and      Quantitatively understand weld alloy
     Weld alloys based on wrought         mitigation technologies     microstructure effects on SCC
       alloy effectiveness             More effective plan            properties
     Visual and ultrasonic NDE            operations and            Advanced sensing and monitoring
        available                         maintenance                  technologies – application to
                                                                       “materials condition”




28
     Technology Enhancement and Basic Science
     Opportunities for Zr Alloys (Fuel Clad, Structures)
                                     Technology
                                       Enhancement                Basic Science Support
     Industrial Solution
                                     Improve model accuracy in
     Established corrosion                                        Mechanisms of corrosion film growth –
                                        real (linear) time and      alloy effects, retardation
        database                        extended service
                                        prediction capability     Understanding of alloying effects
     Specific alloy performance
                                                                     (solute vs 2nd phase) on corrosion
        data vs burnup proprietary                                   film formation
                                     Discriminate heat to heat
        IP for proprietary alloys
                                        and process dependent     Quantitative understanding of
     Post irradiation analysis is       property variability        corrosion rate vs hydrogen pickup
        difficult to perform (High                                  vs mechanical performance
        irradiation doses)           Improve confidence in          (ductility)
     Correlations of environmental      predictions               Quantitative correlations of corrosion
        exposure and reduction in                                   vs mechanical properties (effect of
                                     Ready to implement             hydriding)
        mechanical performance
                                        effective repair and
        (LOCA ductility criteria)
                                        mitigation technologies   Advanced sensing and monitoring
     NDE methods for tubing          More effective plan             technologies for Zr components
       quality inspection and for       operations and
       inplant leakage                  maintenance




29
     “New Build” Plant Technology – Gen III+
     ● These plants are already designed !
     ● Constrained to Fuel/LWR systems
     ● Will be built to already established
       materials and design practices
     ● Use of ASME code materials and
       materials proven by existing plant
       experience
     ● Similar modes of construction welding,
       bolting etc
     ● Replacement materials justified by
       plant experience e.g. Alloy 690 for
       Alloy 600
     ● Materials will be new vintage materials   These plants represent at
       produced by modern (e.g. steelmaking)
       methods
                                                 least those that will come
                                                     on line up to 2035


30
     Reactor Materials Options in New Plants
                 Building on Experience with Existing Plants …
     Low Alloy        Availability in Large Sizes, Forgings rather than Welded Plates,
     steels           Avoid Irradiation Embrittlement by Trace Element Control
     Ni Base Alloys   Alloy 690 Class of Materials has replaced Alloy 600 Class of
                      Materials
     Stainless        304 and 316 Materials have Proven Viable for Long Term
     Steels           Service.
                      The Industry Understands How to Avoid Sensitization Issues
     Zr Alloys        Improved Alloys Will be Used to Withstand Higher Burn-UP


        The New Plant Designs Use Validated Materials Performance
       Currently Applied in Existing Plants to Continue to Meet Better
                   than 90% Capacity Factor Operations



31
     New Plant Materials Technology Issues

     • Manufacturing Issues
     • Product Validation
     • Degradation Mechanism Understanding
     • Operational Assessment Capability
     • Mitigation Approaches
     • Inspection & Evaluation Needs
     • Repair / Replacement Options
     • Regulatory Issues




32
     Concern for New Plants :
     Component Supply




Reactor Pressure Vessel           Reactor Pressure Vessel          Reactor Pressure Vessel
     Bottom Petal                     Core Region Shell              Integrated Type Closure
                                                                     Head
●    Dimension:(mm)               ●   Dimension: (mm)              ●   Dimension: (mm)
     7,636od X 5,290id X 1,631H       7,478od X 7,122id X 3,962H       4,015od 1,705H
●    Weight: 80ton                ●   Weight: 127ton.              ●   Weight: 38ton

         Requirements
                •Manufacturing Infrastructure
                •Testing and Validation
                •Timely Supply




33
     Concern for New Plants :
     Validation of New Component Supply
     High Performance Pressure
     Boundary Components Require :
         Uniform Chemistry and Structure
         Validated Mechanical Properties
         – Strength and Toughness
         Properties must be Exhibited in
         All Sections

                     Supplier as well
                     as component
                     development

     High Performance Production Parts       Integrally Forged Piping
     Require :                             Segments During Processing
     Materials Qualification Tests to
     Support Piece Acceptance




34
     Concern for New Plants :
     Component Fabrication Capability

     ● Large welded Structure
       need processes to
       minimize residual
       stresses etc.




35
     Materials Technology and Basic Science
     Needs for New build Plants
                     Existing Plants                New Build
     Plant           Relicence Existing Gen III     Build New Gen III+ Plants
     Operations      Plants

     Materials       Standard Materials – 30 year   Standard Materials – 2010 Vintage
                     vintage
     Materials       Understand aging and           Validation of new materials
     Technology      degradation of properties.     variants (e.g S level 0.002% spec
     Required        Quantify long time dependent   as <0.030)
                     behavior                       Extension of property database
                     Inspection & Analysis tools    Validate modern processing routes
                     Repair and Replace Options

        Basic science drivers will be similar to those for existing plants – but the
          lifing technology may need to take us out to service beyond 2100




36
     Materials for Next Generation Plants
     ● New systems based on high temperature gas and other coolant media
       (See Gen IV systems)
     ● Opens up the potential for new materials
        – Structural
        – Fuel
        – Fuel cladding
     ● System design confidence for new installations must compete with
       existing LWR concepts
        – Established database
        – Operating history
     ● Materials capabilities will determine design options and operational
       capabilities – but this is not the aeroengine industry !
     ● Materials development for Next Generation plants must provide
       completely verified design database  competition with existing
       materials and concepts.
     ● Development of new materials is unlikely to be commercially driven




37
     Materials Options for Next Generation Plants
     High Temperature Metallics          Ceramics
     ● Enabler for higher efficiency     ● Enabler for higher efficiency
        systems                            systems ?
     ● GT materials have temperature     ● Graphite issues
        capability but very low life
                                             –   Graphite as structural material
     ● Low temperature materials not         –   Aging of graphite
        validated to high temps
                                         ● CMC composites will be proven
     ● Stability of proposed higher        for heat engines
        temperature materials
                                         ● Stability and assurance of new
     Fuel Systems                          ceramics for radiation
                                           applications
     ● Relax restriction to UO2
                                         ● Processing effects on CMC
     ● Relax enrichment restrictions ?
                                           performance
     ● New fuel systems to be proven
                                         ● Stability of proposed higher
       (e.g. TRISO)
                                           temperature materials
         –   Manufacturability
                                         ● Long term compatibility with
         –   Performance/Durability
                                           coolant media
     ● Physical properties/design
       database to be established




38
     Materials Technology Needs for Nuclear
     Power Generation Applications

                  Existing Plants           New Build                     Next
                                                                          Generation
     Plant        Relicence Existing Gen    Build New Gen III+ Plants     Gen IV Plants
     Operations   III Plants

     Materials    Standard Materials – 30   Standard Materials – 2010     New Materials
                  year vintage              Vintage
     Materials    Understand aging and      Validation of new materials   Develop and
     Technology   degradation of            variants)                     validate new
     Required     properties.                                             materials
                  Quantify long time        Extension of property         Extend property
                  dependent behavior        database                      database (higher
                  Inspection & Analysis                                   temperature,
                  tools                                                   longer life)
                                            Validate modern
                  Repair and Replace        processing routes             New processing
                  Options                                                 routes




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