Transcript Chamber Materials - overview and plans

Chamber Materials - overview and plans
OFES Supported Materials Research
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Fatigue thermomechanics (Ghoniem presentation)
High temperature swelling of graphite fiber composite
Critical issues from Chamber Materials Plan (HAPL)
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Transmissive Optics
Formation and annealing of absorption centers
Modeling of cascade and surviving defects in silica
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Reflective Optics
Laser induced damage threshold
Environmental effects (dust/debris)
Modeling surface modification under repetitive pulsing
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Structural Materials
Metallic structure - fatigue and pulsed irradiation effects
Composite System - CFC lifetime
Refractory Armored Composites - basic fabrication and performance
Modeling - Defect formation and migration in graphite
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Safety
Tritium retention in graphite
Materials Working Group Effort
Advisory Group, including:
Jake Blanchard (UW)
Nasr Ghoniem (UCLA)
Gene Lucas (UCSB)
Lance Snead (ORNL)
Steve Zinkle (ORNL)
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Transmissive Optics (Zinkle)
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Reflective Optics (Zinkle, Blanchard, Ghoniem)
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Structural Materials (Snead, Ghoniem, Blanchard, Lucas)
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Safety (Snead)
Critical Path Issues - Graphite Composite
Kiss of Death
Tritium retention(for graphite)
Co-deposition
Swelling and Lifetime
Crucial
Fatigue Properties
Thermal conductivity
RES (for graphite)
Procrastinate
Design codes
Manufacturing large structures
Designing 100% elevated temperature structure
Composite architectural design
OFES Swelling of CFC’s
METS (Mapping Elevated Temperature Swelling) Experiment
Purpose : There is curre ntly no high temperature irradiation data on the high quality graphite
composites being considered for laser IFE. This program will yield data on swelling and
thermal conductivity following neutron irradiation to high temperature and neutron fluence.
Materia ls :
A) Mitsubishi Kasei MK C 1PH (unidirectional CFC)
B) Fiber Material Inc. FMI-222 (balanced CFC)
Irra diation in HFIR Core Region
METS-1 Capsule
METS-2 Capsule
METS-3 Capsule
9 zones in range of
“
“
Kth(@RT)
(W/m-K)
>700
>450
Kth(1000°C)
(W/m-K)
~250
~220
Te mperature
(°C)
600-1500°C
600-1500°C
600-1500°C
Dose
(dpa)
2
4
10
Status:
• All pre-irra diation measurements completed.
• Capsules fabricated and awaiting irra diation in HFIR
• Irra diation planned to begin this FY. Duration 1, 2 and ~7 months.
• Post-irradiation examination to include thermal conductivity and swelling.
ORNL
Critical Path Issues
Refractory Armored Materials
Kiss of Death
Material development
Fatigue Properties
Exfoliation due to ions
Issues relating to structural material
Crucial
Thermal contact resistance and thermal conductivity
Embrittlement (W grain growth, hydrogen effects, irradiation)
In-situ or ex-situ repair
Differential thermal and irradiation expansion
Procrastinate
Manufacturing large structures
Tungsten mobility/safety issues
???
Refractory Armored Composites
• Data mining completed
- refractory armored graphite fiber composites appear hopeless for IFE
- W - SiC system unstable ~ above 1200°C
- Mo - SiC system unstable ~ above 1400°C
• Development program underway (ORNL)
- Refractory : Tungsten (W-Re), Moly (Mo-Re, Mo-Zr-B)
- SiC : CVD beta-SiC, Hot Pressed alpha-SiC, SiC/SiC
Refractory
SiC
Titanium
SiC
Refractory
powder
SiC
• Castellated surface modeling (Blanchard U.W.)
Refractory
powder
SiC
First substrate castellation:
200 mm deep x 200 mm wide
Infrared Rapid Melt Processing and Thermal Shock
5 MW/m2
60 ms
10 ms, ? MW/m2 bursts
QuickTime™ and a
decompressor
are needed to see this picture.
SiC
Specifications: Argon plasma (up to 1MW)
Pulse length : 10 ms (no shuttering)
Rep Rate : 5-10 Hz
Maximum heat flux at maximum area : 5 MW/m2 at 2.5 x 35 cm
Maximum heat flux attainable :12. 5 MW/m2 at 2.5 x 20 cm
Discovery of Unprecedented Strength Properties in Iron Base Alloy
ODS ferritic
• Time to failure is increased by several orders of magnitude
• Potential for increasing the upper operating temperature of iron based alloys
by ~200°C. Work being pursued by DOE OFES, DOE Fossil Energy, others
• IFE will explore grading of new W containing ferritics to W armor
Input into Optics
S.J. Zinkle, et al.
HAPL IFE Program Workshop
San Diego, April 4-5, 2002
NRL IFE 2/2001
Methodology for selecting candidate
radiation-resistant transmissive optics
• Initial list of ~100 optical materials was screened
to select materials with high transparency between
200 and 500 nm
– Numerous optical materials rejected due to too low of
band gap energy (e.g., carbides and most nitrides)
• Requirement of Eg>4 to 6 eV (UV cutoff <200-300 nm)
eliminates many promising candidates, including SiC,
ZnO, TiO2, LiNbO3 and SrO (DPSSL and KRF); and
MgO, ZrO2, Y2O3 and zircon (for KrF)
• Radiation effects literature reviewed for remaining
candidates to select most promising candidates
Original List of Candidate Optical
Materials (transparent at 200-500 nm)
Oxides
Nitrides
CaO, BaO, MgO, AlN
Al2O3, MgAl2O4,
Y2O3, Y3Al5O12,
Al23O27N5, ThO2,
Li2O, LiAlO2,
GeO2, CaWO4,
BaTiO3, KNbO3,
CaTiO3
Alkali halides
LiF, LiCl, NaF,
NaCl, NaBr, KF,
KCl, KBr, KI,
RbF, RbCl,
RbBr, RbI,
MgF2, CaF2,
SrF2, BaF2,
RbMgF3,
KMgF3, KZnF3,
NaMgF3,
LiBaF3
Candidate Radiation-resistant Optical
Materials (no radiation-induced
absorption peaks near 248 or 351 nm)
KrF (248 nm)
CaO, BaO, Y2O3, ZrO2,
ThO2, Li2O, LiAlO2,
BaTiO3, KNbO3, CaTiO3,
NaBr, KCl, KBr, RbCl,
RbBr, RbI, BaF2
DPSSL (351 nm)
BaO, LiAlO2, KNbO3,
CaTiO3, NaBr, KCl, KBr,
RbCl, RbBr, RbI, BaF2
Alkali halides (NaBr, KCl, etc.) are less promising due
sensitivity to radiolysis (displacement damage from ionizing
radiation)
Dielectric Mirrors
•Previous work on irradiation damage in dielectric mirrors showed
poor performance
- LANSCE irradiation, ~100°C, many dpa
- Layered silica structures, glassy substrates
More radiation stable materials are being assembled for irradiation
- Sapphire substrate
- TiO2 (CTE 6.86 E-6) high-Z layer
- Al2O3 ( CTE 6.65E-6) low Z layer
- MgAl2O4 (CTE 6.97E-6) low Z layer
IFE Optics Irradiation
• Capsules to be irradiated to 0.001, 0.005, 0.01 and 0.05 dpa. Irradiation
temperature tentatively 300°C
• Reflective optics for LIDT measurement supplied by Tillack
(Aluminum, SiC, Molybdenum)
• Transmissive optics by Payne and Zinkle
(KU-1 and Corning fused silica, oxides tbd based on white paper)
• Dielectrics by Snead and Payne
(Sapphire sub. TiO2/MgF2 bilayer, Sapphire and TiO2/MgAl2O4)
• Samples to be shipped to LLNL following irradiation
• Status : Design work complete, safety documentation under review
Capsule parts on order, samples on their way
Subwavelength Mirrors
• Subwavelength mirrors use periodic features of order /3 to /2 to
form a surface waveguide which reflects light in a narrow waveband
with very high reflectivity (as high as 99.9%).
• Higher reflectivity allows the use of smaller mirrors.
• Current research is for near-IR wavelengths. Near-UV wavelengths
would simply require smaller feature size.
• Anti-reflectivity coatings can be used to protect the mirror surface.
• This technology is only in the development stage.
Transparent Coating
Reflective Substrate
Anti-reflective protective coatings
• Transparent anti-reflective coatings can be used to protect
the surface of IFE mirrors.
• Mechanical damage to the anti-reflective coating from
debris would not effect the reflective properties of the
underlying mirror surface.
• Roughening of the anti-reflective coating is not necessarily
detrimental to its operation.
• Radiation induced change to absorption in the coating
would still be an issue, but the coating would be much
thinner than a transmissive optic.