Draft Program Plan for Materials R&Din Laser Inertial Fusion Energy (IFE)

L L Snead (ORNL), N. M. Ghoniem (UCLA), J. Sethian (NRL)

with input from

IFE Materials Team, IEA Team and;

P. Levy (BNL), T. Nishitani (JAERI), T. Shikama (Tohoku U), J. Hunn (ORNL)S. Zinkle (ORNL), F. W. Wiffen (DOE), T. D. Burchell (ORNL), R.H. Jones,

R. H. Kurtz, E. Simonen (PNNL)J. P. Bonal (CEA Saclay), C. H. Wu (Garching), J. Davis (Boeing)

L. K. Mansur (ORNL), W. Sommer (LANL), K. Thoms (ORNL), N Sekimura (Tokyo, U)H. Atsumi (Kinki U), R. Causey (SNLL), T. Hino (Hokkaido U)J. Roth and M. Balden (Garching), T. Van Veen (Tech. U. Delft)

Guiding Principles

• There are two distinct missions: - A near-term mission to identify the most likely materials systems for eventualuse in a power plant, and the generation of adequate materials data-base for the design and construction of IRE.- A long-range mission to identify the important materials science phenomenaunique to IFE and the application of this knowledge to develop the materials necessary for a viable power plant.

• The IRE will be in design stage by 2007. An IFE materials handbook including all relevant materials data required for design purposes to be completed.

• The First Wall of the IRE will be representative of a power plant first wall in design and operating temperature. The IRE will include a Test Stand located close to the target.

• Only materials issues pertaining to the construction of the IRE and which are unique to IFE will be considered in the initial stages of the program.

• It is imperative to identify the most important IFE materials issues (show-stoppers) andselect the best individuals and facilities to address them.

Materials Working Group

• The group will provide guidance, review ongoing work, prepare a property handbook, interact with the paper design community, and finally interact with IRE designers.

• Semiannual meetings.

• Final IRE Materials Handbook. Oct. 2006

• Members

Jake Blanchard (U. Wisconsin) Nasr Ghoniem (UCLA) John Davis (Boeing) Jeff Latkowski (LLNL) Sidney Yip (MIT) Lance Snead (ORNL) Steve Zinkle (ORNL) Mark Tillack (UCSD) Gene Lucas (UCSB)/Gary Was(Mich) Gerry Kulcinski (U. Wisconsin)

• To be added in later years, a design code and a manufacturing expert from outside of the fusion community.

Optical Systems Materials Evaluation

Mission : To evaluate material systems and designs for the optical components of IRE andPower Plant, including data bases and anticipated neutron damage and thermomechanical loads.

SOW : Material systems and structural designs will be developed in both IRE and Power Plant applications of final optics. Layered structures, including coatings, substrate and support structures will be developed. Differential dimensional changes due to neutron swelling and thermal strains will be included in designs and analysis.

Optical Systems Materials Evaluation - GIMM

Ongoing FY-01 Work (Tillack UCSD)

June 01 Determination of LIDT with clean surfacesAug 01 Model predictions of wave front from clean surface

Program Plan

Jan. 02 Measure effects of defects and surface contaminants on reflectivity, LIDT and wavefront.Jan. 02 Model reflectivity and wavefront changes due to defects Oct. 03 DP: Definition of primary substrate materialsOct. 05 Swelling of GIMM and GIMM substrateOct. 06 DP: Recommendation of GIMM Structure

Optical Systems Materials Evaluation - Transmissive Optical

Ongoing FY-01 Work (Payne/Latkowski/De La Rubia, LLNL)

• Perform neutron and gamma irradiations of CaF2, SiO2, Al mirrors and other optics• Measure the optical properties of candidate final optic materials (including absorption,

reflection and scatter)• Deduce the effects of annealing the optics at elevated temperature, and its impact on

eliminating the defects.• Develop quantitative models that describe the formation and annealing of defects in the

candidate final optics materials• Extrapolate the measurements to IFE-relevant gamma ray and neutron doses• Fused Silica MD Simulations of Damage in Optical Materials

Ongoing FY-01 Work (Willms, LANL)

• Irradiation of fused silica and other dielectrics in LANSE and WNR.• Post and pre-irradiation sample analysis.• Development of models for color center evolution and loss of optical qualities.

Optical Systems Materials Evaluation - Transmissive Optical

Priority Items and Recommendation

• Continue study of the effects on ionizing and displacive radiation and annealing kinetics.

• Perform in-situ and elevated temperature measurements.

• Perform repetitive irradiation/anneal experiments to more closely represent IFE conditions.

• Define an experiment to verify MD simulations.

• Include ITER-grade KU-1 quartz in experimental matrix. Aggressively pursue collaboration with MFE.

• Investigate the effects of transmutation products.

Optical Systems Materials Evaluation - Transmissive Optical

Program Plan

Sept 02 Low and application temperature neutron irradiationSept 02 Post-Irradiation Annealing StudyApr 02 Measurement of in-situ loss at IRE relevant gamma-fluxJan 03 In-situ neutron irradiation resultsMar 03 DP: Choice of final optic and vacuum window materialMar 04 Repeated neutron dose/anneal of optical materialsOct 07 DP: Recommendation of final optic and vacuum window for PP

Unique IFE Materials Science for FW & Structures

Mission : To develop the knowledge base for understanding fundamental science issues unique to IFE systems.

SOW : The driver for this area is modeling of the unique IFE phenomena, for which there is little understanding, and which have the greatest impact on materials development. Experiments to be guided by the modelingwith the purpose of model validation.

Ongoing FY-01 Work

• X-Ray Ablation Experiments and Analysis, (Payne, LLNL)• Fused Silica MD Simulations of Damage in Optical Materials, (De La Rubia, LLNL)• Pulsed Fusion Neutron Source Development (Dittmier, U Texas)• Molecular Dynamics Simulations of Damage in Chamber Materials, (De La Rubia, LLNL)

Unique IFE Materials Science for FW & Structures

Priority Items and Recommendations

• Provide scientific underpinning for x-ray ablation, pulsed heating and pulsed high-flux neutron damage mechanisms prior to experimental programs.

• Organize workshop to discuss techniques and facilities to experimentally determine pulsed neutron damage.

• Aggressively pursue development and study of high temperature composite. Define mechanical non-irradiated and neutron irradiated physical properties.

• Gain fundamental understanding of thermal conductivity and irradiation-induced thermal conductivity degradation in high temperature composite in order to provide predictivemodels for design use.

• Model and experimentally measure effect of atomic “burn-up” in graphite and silicon carbide.

• Model and measure effects of pulsed heating on composite and metallic structures.

Jan. 02 Modeling pulsed X-ray EffectsMay 03 Model verification of Pulsed X-ray Effects. DP: further investigation?

Mar. 03 Modeling pulsed irradiation effects on structure and propertiesMar. 04 Experimentally verify pulsed irradiation effects. DP: further investigation?

May 04 Modeling cyclic heating and pressure loading on componentsSept. 04 Experimental validation of cyclic heating and pressure loading. DP: further investigation?

Sept 02 Comparison of cascade simulation to experiment in quartz

Unique IFE Materials Science for FW & Structures

Program Plan

Jan. 02 DP: Define most promising CFC Systems (leading candidates Cf/C, SiCf/SiC, and Cf/SiC composites, RA CFC’s).

Sept. 02 Experimentally define effect of high temperature irradiation on thermal conductivity, swelling and structure of Cf/C

May. 03 Modeling of irradiation induced degradation of Kth of Cf/C

Feb. 05 Report on mechanical property evolution in high temperature irradiated CFC’c.

Sept. 06 Experimentally define effect of high temperature irradiation on thermal conductivity, swelling and structure of Cf/C, SiCf/SiC, and Cf/SiC composites, RA CFC’s

Oct 07 DP: Down-select for development and high-dose irradiation and full data-base.

Unique IFE Materials Science for FW & Structures

Program Plan

Development of IRE Chamber Structures

Mission : To develop the data-base and computational tools for successful construction of the IRE chamber in prototypical IFE conditions, excluding neutron effects.

SOW: Materials and structures will be evaluated for early testing in the IRE. The evaluation will lead to integrated experimental tests that typify the conditions of IFE power systems excluding neutron radiation effects.

No ongoing work

Development of IRE Chamber Structures

Priority Items and Recommendations

• Begin aggressive program to develop, define, test and provide design handbook data on candidate materials for IRE. Limit materials selection to those materials applicable to power plant application.

• Define separate paths for data and development needs for near-term materials for IRE first-wall and more speculative test-stand materials.

• Candidate materials to include “intermediate” and “high temperature” materials.

IRE First Wall IRE Test standCommercial C/C Advanced C/CCommercial SiC/SiC Advanced SiC/SiC or SiC/gMolybdenum Alloy Refractory Armored CFCLow Activation Ferritic ODS alloys

Jan. 02 DP: Define Composite System(s) for IFEAug. 02 Fabrication/DevelopmentSept. 03 Bonding DevelopmentAug 04 Thermomechanical property evaluation base materialsFeb. 04 Thermomechanical property evaluation of joined materialsJuly 04 Prototype Testing of Cooled Composite ComponentsSept 04 DP: Define primary IRE composite first wall structuresOct. 05 Composite Component tested at 0.3 FPY

Composites for IRE FW

Jan 02 DP: Define advanced alloy system(s) for IREOct. 02 Thermomechanical property evaluationSept. 03 Low neutron dose, irradiated mechanical propertiesMay 04 Environmental TestingMay 04 Prototype Testing of Cooled ComponentSept. 04 DP: Define primary IRE alloy first wall structureSept. 05 Creep of candidate alloys including irradiationOct 05 Component tested at 0.3 FPY

Alloys for IRE FW

Development of IRE Chamber Structures

Advanced Composites for IRE Test Stand

Development of IRE Chamber Structures

Oct. 03 DP : Define composite system(s) Aug. 04 Fabrication/Development Feb 04 Complete Refractory Armored CFC Development Sept. 04 Bonding and hermetic Development Dec. 04 Thermomechanical property evaluation base material Feb. 05 Thermomechanical property evaluation joined material May 05 Prototype Testing of Cooled Component Oct. 05 DP : Define primary test stand alloy first wall structure Oct 06 Component tested at 0.3 FPY

Surface Modification Science & Technology

Mission : To determine the physico-chemical mechanisms of Radiation Enhanced Sublimation (RES) and surface erosion, and to develop surface modification techniques for its mitigation.

SOW : The mechanisms of surface erosion and RES will be determined. Dopants and surface implantation techniques will be utilized to reduce these effects.

Oct. 03 Modeling IFE irradiation on Radiation Enhanced Sublimation in Cf/COct 04 Moderation of the effects of RES utilizing dopantsOct 05 Comparison of sublimation model results with experimentsMay 03 Experiments and Models of Physical and Chemical Erosion due to thermal pulsing in

metallic and CFC’s

Materials Impact on Safety, Economics & Environmental

Mission : To assess the impact of material selection in chamber and optical components onthe economics, safety and environment during normal and accidental plant operations. IFE relevant scenarios are to be emphasized.

SOW : A mechanistic model for tritium migration and retention in graphitic materials will be developed. A global tritium inventory and release model will be developed and validatedby experiments. The impact of shallow land burial and recycling considerations on material selection will be determined.

Sept 02 Develop models of tritium attachment to graphite and total plant tritium inventorySept 03 Experimentally measure D-2 attachment in high temperature neutron irradiated Cf/C? Assess the impact of material selection on chemical compatibility between coolants

and structures.? Address issues relevant to economics and operation of power plant (eg Blankets,

interaction with design, etc)

• There are two distinct missions: - A near-term mission to identify the most likely materials systems for eventualuse in a power plant, and the generation of adequate materials data-base for the design and construction of IRE.- A long-range mission to identify the important materials science phenomenaunique to IFE and the application of this knowledge to develop the materials necessary for a viable power plant.

• The IRE will be in design stage by 2007. An IFE materials handbook including all relevant materials data required for design purposes to be completed.

• The First Wall of the IRE will be representative of a power plant first wall in design and operating temperature. The IRE will include a Test Stand located in close proximity to the target. Design data for proposed test stand materials to be assembled.

• Only materials issues pertaining to the construction of the IRE and which are unique to IFE will be considered in the initial stages of the program.

• It is imperative to identify the most important IFE materials issues (show-stoppers) andselect the best individuals and facilities to address them.

Discussion Topic 1 : Guiding Principles

Discussion Topic 2 : Function of Materials Working Group

• The group will provide guidance, review ongoing work, prepare a property handbook, interact with the paper design community, and finally interact with IRE designers.

• Semiannual meetings.

• Final IRE Materials Handbook. Oct. 2006

• Members

Jake Blanchard (U. Wisconsin) Nasr Ghoneim (UCLA) John Davis (Boeing) Jeff Latkowski (LLNL) Sidney Yip (MIT) Lance Snead (ORNL) Steve Zinkle (ORNL) Mark Tillack (UCSD) Gene Lucas (UCSB)/Gary Was(Mich) Gerry Kulcinski (U. Wisconsin)

• To be added in later years, a design code and a manufacturing expert from outside construction of the fusion community.

Discussion Topic 3 : Balance between in-situ and ex-situ transmissive optical measurements.

• Several groups have measured transient absorption significantly higher than the residual, post-irradiation absorption.

• The need for irradiations at elevated temperature could make in situ measurement essential..

• In situ measurement more difficult and higher cost.

• If transient absorption effects are important than how critical is dose rate?

What irradiation facilities are available for in situ work?

Univ. of Illinois TRIGAUniv. of Michigan’s Ford ReactorBNL 60Co sourceVarious KrF lasersJAERI-FNSothers

0

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Absorption Coefficient

α

( 10x

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-1)mm

( )Time s

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90

Dose( / )kGy s

7940 Corning Fused Silica325 nm

TRIGA Irradiation @ RT

2Miley

10 20 30 1000750500

RT Annealing.Irr

., . . . 18 (1991) 341Miley et al Fus Eng Des

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Optical Density (cm

-1)

Fluence (10 19 n/m2)

14 MeV FNS IrradiationKU-1 Quartz

Room Temperature

14 hrNo Irradiation

FNS Plot

T. Nishitani Draft Data (to be published ICFRM-10)

BNL’s 60Co source

-J. Kierstead, P. Levy

Leclerc et al., J. Non-Cryst. Sol. 149 (1992) 115

Univ. of Illinois TRIGA

Discussion Topic 4 : Room temperature or application temperature irradiation of optics?

• Is there a difference between operation at 400°C and post-irradiation thermal treatment at 400°C?

• Post-irradiation thermal treatment can reduce absorption without removing defects which are precursors to color center formation. Additional ionizing radiation rapidly reactivates these absorption centers.

• Should we study temperature dependence of irradiation effects?

Discussion Topic 5 : How do we deal with dimensional changes in a final transmissive optic and GIMM substrates?

-->3% compaction of silica expected for 1020 n/cm2. -->10% expansion in SiC at 1021 n/cm2.

Neutron Fluence (1/cm ) x 102 19

0 48121620 2.2

2.3

2.4

2.5

2.6

Quartz

Vitreous Silica

0.1

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Volumetric Swelling (%)

Irradiation Temperature (C)

void swelling regimepoint-defect swellingamorphization

Discussion Topic 6 : What are the appropriate irradiation needs?

Need for Pulsed Irradiation Facility ???

--> Extremely high displacement rate and short pulse will effect microstructure

--> Pulsed nature will feed synergy between gamma and displacement induced F-centers

Need for High Energy Neutrons ???

--> Spectrum of neutrons seen by components

--> Energy dependent cascades (spectrum effects)

--> Effect of transmutation gas

IFE(Li protected)

IFE(non-Li protected)

Heavy IonAccelerator

(4 MeVnickel)

HFIRFast

Neutrons

HVEM(1 MeV

electrons)

RHICBooster

(BNL P+→A )u

IFMIF(t )bd

Peak DisplacementRat ,e dpa/s

0.1 1-10 0.1-0.4†*10-7-10-6 10-3 10-7-10-1 ~10 -7

Average DisplacementRate, dpa/s 10-7-10-6 10-6- 2 1x 0-5 10-7-10-3 10-7-10-6 10-3 10-8-10-2 ~10 -7

Peak Particl e Fluxcm-2/s ~ 5x 1020 ~ 5 x 1020 1012 –1013 1015 1015 1014-1015 1015

Pulse Width ns

10 10 2 steadystate

steadystate

100 steadystate

Pulse Repetition Rate Hz

10 10-20 d c t o 107 dc dc 3 dc

Helium Productionappm-yr-1

6*-300** 50†-7000 †† if dualbeam

injection

1-30 none ? 10-400

*HYLIFE design.**LA SL wetted wal l desig .n†Dry meta l wall.††Graphite wall.†*0.1 dpa/s corresponds t o 1 μA bea m focuse d t o a 2 mm diame terbeam of 25 μA/cm2 and 0.4 dpa/s to a 1 m m diameter be am withdensity of 100 μA/cm2.

Comparision of needs and existing facilities for IFE Irradiation

Details of Target Output Spectra, Radiation Transport in Chamber Gas and Heat Transfer in Wall are All Important and

Modeled with BUCKY

•The separation in time of the insults from the prompt x-ray, the ions, and the re-radiated x-rays is crucial to the survival of the wall.

•The Xe serves to absorb the vast majority of the ion energy and almost half of the prompt x-rays and slowly re-radiates the absorbed energy at a rate determined by the Plank emission opacity of the Xe.

•Neutron deposition begins after 1st peak but continues into 2nd.

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Energy Dependent Material Damage for SOMBRERO

First Wall

Rear of Blanket

Final Optic

Relative Damage (% dpa)

Neutron Energy (MeV)

High Energy

Intermediate Energy

4 % damage96% damageFirst Wall1%99%Rear of Blanket69%31%Final Optic

Based on Latkowski Calculation5/17/01Assumes carbon cross-section

Displacement Damage Mechanisms are being investigated with Molecular Dynamics Simulations

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are needed to see this picture.

PKAs oriented in the close packed planes produce enhanced damage efficiency at low energies compared to other orientations, due to a planar defect creation process

Damage efficiency saturates when subcascade formation occurs

300 eV PKA

Fission (0.1 - 3 MeV)

5 nm

Peak damage state iniron cascades at 100K

50 keV PKA(ave. fusion)

10 keV PKA(ave. fission)

MD computer simulations show that subcascades and defect production are comparable for fission and fusion

Similar defect clusters produced by fission and fusion neutrons as observed by TEM

Fusion (14 MeV)

Similar hardening behavior confirms the equivalency

Discussion Topic 7 : Choice of first wall and test stand materials and their data needs…

• The materials program is divided into two missions:

Near term IRE - extensive data-base required, high reliability neededexisting materials

Power Plant - development requiredrudimentary tests sufficient

Discussion Topic 8 : Can we rely on existing database on RES and erosion?

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1 keV H1 keV D3 keV He

Temperature (C)

PhysicalSputtering

Chemical Erosion

Radiation Enhanced Sublimation

Discussion Topic 9 : Are there IFE-specific show-stoppers with regards to safety?

• Tritium retention in graphite.

• Corrosion/mass transport.

• Operations/safety issues.

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T-3

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on (

app

m)

Irradiation / T-3 Loading Temperature (C)

Non-irradiated, infinite charge time

Non-Irradiated1 hr Charge Time

High Quality Irradiated CFC (Causey, Snead)

Intermediate Quality Irradiated Graphite (Causey, Snead)

• T-3 attaches to basal plane edges and highly defected structure. More perfect material and/or high temperature allows less retention.

Tritium Retention in Graphite

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UnirradiatedNeutron Irradiated

Hydrogen Solubility (appm)

Graphitic Perfection (%)

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N3M graphiteFMI-222 CFCMKC-1PH CFC

Tritium Retention (appm)

Radiation Damage (dpa)

Atsumi dataTirr=600°C

Tload=1000°C

Causey/Sneaddata

Tirr=200°C

Tload=1000°C

Tritium Retention in Graphite

• There is no data on the tritium retention of high-temperature (>1000°C) irradiated CFC.• There is very limited data on high quality CFC.• Data on retention in “dust” and co-deposited material is being generated by ITER...

SOMBRERO CHAMBER GRAPHITE DATA

Mass of graphite in chamber (tonnes) 454Thickness of FW (cm) 1.0Mass of FW (tonnes) 6.8Surface area of FW (m2) 378Density of FW graphite (g.cm2) 1.8Steady state conditions, ie equilibrate after shot:Max, FW outside Temp. (C) 1438Max. FW inside Temp. (C) 1225Min. FW outside Temp. (C) 1040Min. FW inside Temp. (C) 770Max. Temp. in back of chamber (C) 840Min. Temp. in back of chamber (C) 620

Inlet LiO2 Temp. (C) 550Outlet LiO2 Temp. at FW (C) 700Outlet LiO2 Temp. in back of chamber (C) 800

All external and internal surfaces of the graphite with the exceptionOf the FW are coated with 35 microns of SiC.

Mitsubishi KaseiMKC-1PH CFC

X Y ZYoung'sModulus(GPa)

Unirr.

Irr.

74.0

98.0

-

-

87.6

87.2BendingStrength(MPa)

Unirr.

Irr.

103.9 +/- 6.8

98.4 +/- 2.7

5.8 +/- 2.5 99.2 +/- 17.6

88.9 +/- 8.2CompressiveStrength(MPa)

Unirr.

Irr.

59.8 +/- 6.8

55.9 +/- 3.1

76.7 +/- 14.0

-

59.6 +/- 6.7

51.0 +/- 7.3LengthChange (%)

Irr -0.39 -0.97

Irradiation Induced Dimensional Change in Advanced CFC’s

• Interstitials created during irradiation form new graphitic basal planes leading to highly anisotropic dimensional changes.• Engineering composites can “balance” and minimize such dimensional changes

• There are no very high temperature data on advanced CFC’s.

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irradiated

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MKC-1PH High Conductivity CFC

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Effect if Irradiation on Thermal Conductivity

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SiC/SiC Composite (transverse)

P55 Graphite/CVI SiC (high TC)

Morton CVD SiC

CVI SiC (high TC)

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SiC/SiC Composite (transverse)

P55 Graphite/CVI SiC (high TC)

Morton CVD SiC

CVI SiC (high TC)

• At IFE-relevant temp., SiC matrix / graphite fiber :

--> conductivity exceeds present SiC/SiC--> conductivity exceeds SiC theoretical maximum--> exceeds SOMBRERO assumptions

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CVD SiC/K1100 Non-Irradiated

CVD SiC/K1100 Irradiated

CVD SiCNon-Irradiated

CVD SiC Irradiated

• At IFE-relevant temp., SiC matrix / graphite fiber :

--> irradiated TC exceeds maximum for SiC

--> exceeds SOMBRERO assumptions

• irradiated values are empirically determined

US/Monbusho “Jupiter” Program

We Now Have First Radiation Hard SiC Composite

Bend strength of irradiated“advanced” composites show

no degradation