materials issues, gaps and research needs rj kurtz 1 and the renew materials panel 1 pacific...
Post on 13-Dec-2015
220 Views
Preview:
TRANSCRIPT
Materials Issues, Gaps and Materials Issues, Gaps and Research NeedsResearch NeedsMaterials Issues, Gaps and Materials Issues, Gaps and Research NeedsResearch Needs
RJ Kurtz1 and the ReNeW Materials Panel
1Pacific Northwest National Laboratory
Harnessing Fusion Power WorkshopLos Angeles, CAMarch 2 - 4, 2009
ReNeW Materials Panel MembersReNeW Materials Panel Members
Name Affiliation EmailRick Kurtz, Leader PNNL rj.kurtz@pnl.gov
Mike Mauel Columbia mauel@columbia.edu
Mike Nastasi LANL nasty@lanl.gov
Bob Odette UCSB odette@engineering.ucsb.edu
Shahram Sharafat UCLA shahrams@ucla.edu
Roger Stoller ORNL stollerre@ornl.gov
Steve Zinkle ORNL zinklesj@ornl.gov
Greenwald Panel Materials IssuesGreenwald Panel Materials Issues
Issue DescriptionMI-1 Constitutive mechanical properties of structural and breeding blanket materials after thermal and
irradiation exposure including joints and dissimilar material transition regions.
MI-2 Dimensional and phase stability of structural and breeding material systems due to neutron irradiation.
MI-3 Scientific basis for high-temperature design criteria.
MI-4 Quantitative predictive model for thermal conductivity degradation of neutron irradiated metals and ceramics.
MI-5 Physical mechanisms controlling the chemical dissolution of materials exposed to coolants, including mass transfer phenomena associated with surrounding dissimilar solid materials.
MI-6 Mechanisms responsible for radiation-induced changes in electrical resistance and optical properties in dielectric materials.
MI-7 Exploration of reduced-activation and reduced-decay-heat compositions that simultaneously provide high structural material performance.
Overarching Issue: Understand the basic materials science phenomena for fusion breeding blankets, structural components, plasma diagnostics, and heating components in high neutron areas.
Greenwald Panel Materials GapsGreenwald Panel Materials Gaps
Gap Description
GM-1 Predictive multiscale models of materials behavior in the fusion environment.
GM-2 Constitutive mechanical properties of structural and breeding blanket materials in the fusion environment.
GM-3 Dimensional and phase stability and physical property degradation in the fusion environment.
GM-4 Science basis for robust high-temperature design criteria.
GM-5 Chemical compatibility of materials in the fusion environment.
GM-6 Fabrication and joining of complex structures.
ReNeW Panel Materials IssuesReNeW Panel Materials Issues
Issues Systems ComponentsAlloy Development FW/Blanket/Shield, Vacuum
Vessel, Divertor/PFCStructural & HHF Materials
Chemical Compatibility FW/Blanket/Shield, Vacuum Vessel, Divertor/PFC
Structural & HHF Materials, Tritium Breeding & Neutron Multiplier Materials, Tritium Extraction, HX & Piping
Design Criteria FW/Blanket/Shield, Vacuum Vessel, Divertor/PFC, Magnets
Structural & HHF Materials, Neutron Shielding, Tritium Extraction, HX & Piping, Magnet Materials
Erosion Divertor/PFC HHF Materials
Fabrication & Joining FW/Blanket/Shield, Vacuum Vessel, Divertor/PFC
Structural & HHF Materials, Neutron Shielding, Tritium Extraction, HX & Piping
Plasma-Material Interactions Divertor/PFC HHF Materials
Radiation Effects FW/Blanket/Shield, Vacuum Vessel, Divertor/PFC, Magnets, Functional
Structural Materials, Tritium Breeding & Neutron Multiplier Materials, HHF Materials, Magnet Materials, Plasma Diagnostic Materials, Optical Materials, Mirrors
Safety, Licensing, RAMI FW/Blanket/Shield, Vacuum Vessel, Divertor/PFC
Structural & HHF Materials
Thermal Creep & Fatigue FW/Blanket/Shield, Vacuum Vessel, Divertor/PFC
Structural & HHF Materials, Tritium Breeding & Neutron Multiplier Materials
Tritium Inventory FW/Blanket/Shield, Divertor/PFC Tritium Breeding & Neutron Multiplier Materials, Tritium Extraction, HX & Piping, HHF Materials
Tritium Permeation FW/Blanket/Shield Tritium Breeding & Neutron Multiplier Materials, Tritium Extraction, HX & Piping
Materials Research and the Path to Materials Research and the Path to Fusion PowerFusion Power
Materials research to identify candidate materials- Radiation damage- Activation- Mechanical & physical properties- Compatibility with coolants and tritium breeders- Large-scale fabrication & joining issues
Identify and demonstrate approaches to improve material performance
Identify concept specific issues and demonstrate proof-of-principle solutions, e.g.
- Design with ferromagnetic material- Methods for design of large, thermo-mechanically loaded
structures
Development of materials with acceptable performance and demonstrate to goal life (dpa, He)
Demonstrate solutions to concept specific issues on actual structural materials and prototypic components
Develop design data base, constitutive equations, and models to describe all aspects of material behavior required for design and licensing
Ion Accelerators
RTNS
Fission Reactors
IFMIF
Component Test Facilities
Actual Fusion Environment Test Results
Plasma Physics Confinement
Fusion Reactor Concept Definition
ITER
DEMO Conceptual
Designs
DEMO Final Design &
ConstructionKey need is close integration of materials science with the structural analysis-design process.
Current Development Status of Current Development Status of Fusion Structural MaterialsFusion Structural Materials
UnirradiatedIrradiated
RAF/M Steels
V Alloys
NFA Steels
SiC/SiC
W Alloys
UnirradiatedIrradiated
UnirradiatedIrradiated
UnirradiatedIrradiated
UnirradiatedIrradiated
ConceptExploration
Proof ofPrinciple
PerformanceExtension
Feasibility Tech. maturation
Low-Activation Structural Materials Low-Activation Structural Materials for Fusionfor Fusion
None of the current reduced or low-activation fusion materials existed 15 years ago.
Low-activation is a must!!
IFMIF
Spallationneutrons
Fusionreactor
ITER
10
15
10
16
10
17
10
18
10
19
10
20
10
21
10
5
10
6
10
7
10
8
10
9
Magnetic
Inertial
( )Ion Temperature K
1955
1960
1965
1970-75
1975-80
1980s
1990s
Breakeven
Ignition
Extrapolation to fusion regime is much larger for the fusion materials than for plasma physics program.Lack of an intense neutron source emphasizes the need for a coordinated scientific effort combining experiment, modeling and theory to a develop a fundamental understanding of radiation damage.
Fusion Materials Relies Heavily on Modeling due Fusion Materials Relies Heavily on Modeling due to Inaccessibility of Fusion Operating Regimeto Inaccessibility of Fusion Operating Regime
He and Displacement Damage Levels
Steels
Impact of He-Rich Environment on Impact of He-Rich Environment on Neutron Irradiated MaterialsNeutron Irradiated Materials
A unique aspect of the DT fusion environment is substantial production of gaseous transmutants such as He and H.
Accumulation of He can have major implications for the integrity of fusion structures such as:- Loss of high-temperature creep strength.
- Increased swelling and irradiation creep at intermediate temperatures.
- Potential for loss of ductility and fracture toughness at low temperatures.
Grain boundary
1
10
100
1000
Un-implanted 200 appm He
316 SS @ 750°C & 100 MPa
Science-Based High-Temperature Science-Based High-Temperature Design CriteriaDesign Criteria
Current high-temperature design methods are largely empirical.
Cyclic plastic loading is far more damaging than monotonic loading.
New models of high-temperature deformation and fracture are needed for:• Creep-fatigue interaction.• Elastic-plastic, time-dependent fracture mechanics.• Materials with low ductility, pronounced anisotropy,
composites and multilayers.
10 100 800600
1000
1500
2000
2500
3000
COMPRESSION HOLD-TIME
SYMMETRICAL HOLD-TIME
TENSION HOLD-TIMEZEROHOLD-TIME
EUROFER 97 T=550°C Δεt=1.0%
, NUMBER OF CYCLES TO FAILURE N
f
TIME PER CYCLE, S
J. Aktaa & R. Schmitt, FZK, 2004
Breaking the High Strength-Low Breaking the High Strength-Low Toughness/Ductility ParadigmToughness/Ductility Paradigm
Increased strength is accompanied by reduced toughness (cracking resistance) and ductility.
Strength is increased by alloying, processing and radiation damage.
Low toughness and ductility reduce failure margins.
The benefits of simultaneously achieving high-strength and high ductility/ toughness would be enormous.
Toughness or Ductility
Stre
ngth
Theoretical Strength ~E/50
Future Materials
Current Engineering Materials
Fundamentals of Material-Coolant Chemical Fundamentals of Material-Coolant Chemical Compatibility in the Fusion EnvironmentCompatibility in the Fusion Environment
The traditional approach to corrosion is empirical.
Correlations do not capture basic physics and have limited predictive capability.
Opportunities: Controlled experiments
combined with physical models utilizing advanced thermodynamics & kinetics codes.
Integrated experiments using sophisticated in situ diagnostic and sensor technologies.
M. Zmitko / US-EU Material and Breeding Blanket Experts Meeting (2005)J. Konys et al./ ICFRM-12 (2005)
Theory and Modeling of Materials Theory and Modeling of Materials Performance Under Fusion ConditionsPerformance Under Fusion Conditions
Integration of modeling-theory-experiments-database development is a critical challenge in bridging the multi-physics-length-time scales.
• Microstructural evolution in a high-energy neutron, He-rich environment.
• Resulting in degradation of performance sustaining properties and stability.
• Effects of He are critical.
• Success - simulations and experiments show high-energy fusion damage events are similar to multiple, lower-energy events - provides fission-fusions dpa damage scaling.
Comparison of 10 and 50 Comparison of 10 and 50 keV displacement keV displacement cascades in ironcascades in iron
100K, iron
50 keV
10 keV
5 nm
Coupling of Modeling and Experiment Coupling of Modeling and Experiment to Determine He Transport and Fateto Determine He Transport and Fate
0.0001
0.001
0.01
0.1
1
0 0.02 0.04 0.06 0.08 0.1
dΣ/dΩ [(cm•ster)
-1]
q2 (Å-2)
SANS/ASAXS PAS
LMC: NuclearLMC: Nuc + Mag
SANS: NucSANS: N+Mag
0.001
0. 01
0.1
1
0 0.01 0.02 0.03 0.04 0.05 0.06
dS/d W
(cm
-1•s
ter
-1)
q2 (Å- 2)
feature‘signals’
Multiscale modelingTEM, SANS, Positron theory
predictfeatures
simulateobservables
self-consistent ‘understanding’of He effects
Experimental characterizationTEM THDS
HeFe
GR Odette, UCSB & BD Wirth, UCB
Compelling Scientific Needs - ICompelling Scientific Needs - I
Recent fusion materials R&D efforts have led to the development of high-performance reduced-activation structural materials with good radiation resistance for doses ~30 dpa and ~300 appm He.
The overarching scientific challenge facing structural materials for DEMO is microstructural evolution and property changes (mechanical and physical) that may occur for neutron doses up to ~200 dpa and ~2000 appm He.
Development of high-performance alloys and ceramics including large-scale fabrication and joining technologies is needed.
Current understanding of strength-ductility/toughness relationships is inadequate to simultaneously achieve high-strength and high-ductility and toughness.
Compelling Scientific Needs - IICompelling Scientific Needs - II
Better mechanistic physical models of thermo-mechanical degradation are needed for development of advanced materials and science-based high-temperature structural design criteria.
The mechanisms controlling chemical compatibility of materials exposed to coolants and erosion of materials due to interaction with the plasma are poorly understood.
Better understanding of radiation-induced and thermo-mechanical property changes in high-heat flux materials (tungsten), magnet, and a host of functional materials is required.
Critical Resource Needs - ICritical Resource Needs - I
Research Scientists and Engineers• Many specialized skills will be needed – physical metallurgists, ceramists,
electron microscopists, mechanical property specialists, fracture mechanics, materials evaluation specialists (SANS, PAS, APT, etc.), corrosion scientists, nondestructive evaluation specialists, theory and modeling experts (multiscale materials modeling).
• 2003 FESAC Development Plan estimated ~60 FTE/y at peak activity.• Existing talent pool rapidly shrinking!
Materials Science Facilities• Materials evaluation equipment – TEM, SEM, FIB, Auger, APT, etc.• High-temperature materials testing – creep, fatigue, fracture, thermal-shock and
fatigue.• Compatibility testing – flow loops for corrosion testing, oxidation.• Physical property measurements – thermal, electrical, optical, etc.• Material fabrication and joining of small to large-scale components.• Hot cells for handling and testing of activated materials.
Critical Resource Needs - IICritical Resource Needs - II
Non-Nuclear Structural Integrity Benchmarking Facilities• Facilities for testing various components such as blanket modules are needed to
investigate the potential for synergistic effects that are not revealed in simpler single-variable experiments or limited multiple-variable studies.
• Provides data to refine predictive models of materials behavior.• Gives reliability and failure rate data on materials, components and structures to
valid codes for designing intermediate step nuclear devices and DEMO.• Test bed to test and evaluate nondestructive inspection techniques and
procedures. Other Facilities
• Extensive computational resources will be needed at all phases of fusion materials development to support model development but, in particular, large-scale structural damage mechanics computational capability will be needed to guide and interpret data obtained from component-level test facilities.
Critical Resource Needs - IIICritical Resource Needs - III
Fission Reactors• The capability to perform irradiation experiments in fission reactors is essential
for identifying the most promising materials and specimen geometries for irradiation in an intense neutron source.
Intense Neutron Source• Overcoming radiation damage degradation is the rate-controlling step in fusion
materials development.• Evaluation of radiation effects requires simultaneous displacement damage
(~200 dpa) and He generation (~2000 appm).• International assessments have concluded that an intense neutron source with ≥
0.5 liter volume with ≥ 2 MW/m2 equivalent 14 MeV neutron flux to enable testing up to a least 10 MW-y/m2, availability > 70%, and flux gradients ≤ 20%/cm is essential to develop and qualify radiation resistant structural materials for DEMO.
Critical Resource Needs - IVCritical Resource Needs - IV
Component Test Facility• Nuclear facility to explore the potential for synergistic effects in a fully integrated
fusion neutron environment. Data and models generated from non-nuclear structural test facilities, fission reactor studies and the intense neutron source will be needed to design this facility.
top related