Future Work

1

• Future Work
• ORNL Chamber Materials Studies
• Materials Working Group
• L L Snead and S. J. Zinkle (ORNL)
• J. Blanchard (UW)
• N. Ghoniem (UCLA)
• G. Lucas (UCSB)

2
Conclude Fundamentals of Helium Trapping in W
Complete series of high-temperature
implantations and associated TEM to determine
controlling microstructural feature. Are grain
boundaries or impurities controlling trapping?
Complete thermal desorption studies. Determine
diffusion coefficient of He in W for transport
modeling Automate and carry out IFE relevant
dose/anneal study on candidate tungsten material.
Which material? Perform degraded energy
implantation of He/H. Simulating actual spectrum
calculated described by Lucas
3
Development of Refractory Armored Materials
Conclude tungsten coated SiC work by
completing thermal stability of W/SiC interphase
following thermal fatigue testing
Parallel with new work (limited resources
required) Is this sufficient for proof- of
principal or do we need to armor SiC/SiC
composite?
Wcoating
WSi
WC
SiC
10µm
Back scattering electron image
4
Primary Candidate First Wall Structure W/LAF
Issues and development to address for archival
publication
Development of Armor fabrication process and
repair He management mech. thermal fatigue
testing Surface Roughening/Ablation Underlying
Structure bonding (especially ODS) high cycle
fatigue creep rupture Armor/Structure
Thermomechanics design and armor thickness finite
element modeling thermal fatigue and
FCG Structure/Coolant Interface corrosion/mass
transfer coating at high temperature? Modeling
Irradiation Effects swelling and embrittlement
Porous W Structure
Monolithic W
Liquid Metal Helium,or Salt Coolant?
LAF(600C max) or ODS(800C) structure,
possibly both.
5
Development of Armor Tungsten-Clad F82H Steel
I. Diffusion-bonded tungsten foil (.1 mm
thickness) - Allows the best possible
mechanical properties and surface integrity -
Tungsten will remain in the un-recrystallized
state - No porosity II. Plasma-sprayed
tungsten transition coatings - Allows for a
graded transition structure by blending tungsten
and steel powders in an
intermediate layer to accommodate CTE
mismatch. - Resulting microstructure is
recrystallized but small grain size - May be
spayed in vacuum or under a cover gas -
Variable porosity III. Diffusion-bonded W foil on
sprayed intermediate layer.
Testing to include tensile fatigue and
thermal fatigue. Goal After determining optimum
coating method and W thickness, thermally fatigue
(1x8 cm min.) component to verify interface
stability and compare to finite element modeling.
6
Support for Tungsten Foams
Support for Foam Evaluation - thermal
transport measurements - helium trapping
7
Effort of Materials Working Group
Coordination of materials studied under
chamber materials program (Snead) Analysis
and standardization of various irradiation
sources used in chamber materials experiments.
(Blanchard, Snead) Fatigue and crack growth of
first wall armor and structure (Zinkle,
Blanchard) Modeling of first wall helium
management (Lucas, Ghoniem) Engineered first
wall armor (S.F.K.A. Sharafat, Snead)
Structural requirments/deficiencies for LAF and
ODS structure. (Zinkle, et al)
8
Round Robin Materials
Structural materials under the HAPL program
are being coordinated to ensure uniformity in
materials chemistry, thermomechanical properties,
history and where appropriate the surface
condition (eg polishing for surface studies.)
Currently, the candidate materials being
distributed are Tungsten Zone refined single
crystal (99.999) Chemically Vapor Deposited
(99.995) Powder met.
Polycrystalline (99.99) Tungsten-Rhenium
(tbd, W-26Re-HfC(0.25) ) Low Activation
Ferritic (F82H) Oxide Dispersion Strengthened
Steel (MA-957 to be replaced FY06) Graphite
FMI-222 balanced weave pitch fiber/matrix
composite Segri Great Lakes Near Isotropic
Candidate Nuclear Graphite