Materials Science and Development in Support of Inertial Fusion Energy Lance Snead Steven Zinkle...
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Transcript of Materials Science and Development in Support of Inertial Fusion Energy Lance Snead Steven Zinkle...
Materials Science and Development in Support of Inertial Fusion Energy
Lance SneadSteven Zinkle
Timothy Burchell
Oak Ridge National Laboratory
Presented at the Laser IFE Program WorkshopNaval Research Laboratory, February 6,7 2001
Research Areas Briefly Covered :
• Thermal Conductivity Modeling (SiC, graphite and composites) • Characterizing and Reducing Radiation Induced Dimensional Changes in CFC’s (IFE Funded, 50k$/yr, 3 year)• Advanced Composites and Low Tritium Retaining Materials (For IFE Proposal)
NRL IFE 2/2001
0
100
200
300
400
500
0 200 400 600 800 1000 1200 1400 1600
Temperature (°C)
MKC-1PH
FMI-222
RGTi
H451
Copper
Present-Day High Thermal Conductivity Materials
NRL IFE 2/2001
Thermal Conductivity Modeling (SiC, graphite and composites)
• Irradiation-induced thermal conductivity degradation in ceramics and graphite is dominated by defect-phonon scattering. Understanding this interaction allows accurate modeling and prediction.
1Kirr(T)
=1
Kumklapp(T)+
1KG.B.(T)
+1
Krd(T)
1Krd(T)
=1
Kirr(T)−
1Kunirr(T)
• The defect resistance term, 1/Krd, is a simple, intrinsic material property .
NRL IFE 2/2001
0.01
0.1
1
10
0.01 0.1 1
Neutron Damage (dpa)
Pyrolitic Graphite(K
RT = 1100 W/m-K)
Compilation 1/Krd
H451 Graphite(KRT = 124 W/m-K)
RGTi (KRT
= 450)
MKC1PH (KRT
=519)
Irradiation Temperature 500°C
Thermal Conductivity Modeling (SiC, graphite and composites) - data on defect resistance -
NRL IFE 2/2001
HFIR IrradiationSnead/Burchell
0
1
2
3
4
300 400 500 600 700 800 900 1000 1100 1200
0.0 DPA0.001 DPA0.005 DPA0.01 DPA0.05 DPA0.1 DPA0.5 DPA1 DPA
Th
erm
al
Co
nd
uc
tiv
ity
(W
/cm
-K)
Irradiation Temperature (°C)
unirradiated
irradiated
DPA=displacement per atom
Predicting Thermal Conductivity Degradation of Advanced CFC’s
NRL IFE 2/2001
- combining theroetical model and measured data -
MKC-1PH High Conductivity CFC
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
1000°C, 10 dpa
• 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.
NRL IFE 2/2001
Oku Data
METS (Mapping Elevated Temperature Swelling) Experiment
Materials : Kth(@RT) Kth(1000°C) (W/m-K) (W/m-K)
A) Mitsubishi Kasei MKC 1PH (unidirectional CFC) >700 ~250B) Fiber Material Inc. FMI-222 (balanced CFC) >450 ~220
Irradiation in HFIR Core Region Temperature Dose (°C) (dpa)
METS-1 Capsule 9 zones in range of 600-1500°C 2METS-2 Capsule “ 600-1500°C 4METS-3 Capsule “ 600-1500°C 10
Status:• All pre-irradiation measurements completed• Capsules fabricated• Irradiation planned to begin this FY. Duration 1, 2 and ~7 months.• Post-irradiation examination to include thermal conductivity and swelling.
NRL IFE 2/2001
SiC/Graphite System: Engineering Low T-3 retention, High Conductivity Material
Why SiC/Graphite fiber
Combines Advantages of SiC composite : Low tritium retention With Advantages of Graphite fibers : Very high thermal conductivity
Where we are
First attempt at manufacture completed--> thermal conductivity promising--> mechanical properties similar to SiC/SiC composites--> tritium retention measurements underway (Causey)
Drawbacks
--> New material system -->Unknown mechanical performance
-->Unknown radiation performance
NRL IFE 2/2001
1
10
100
1000
200 400 600 800 1000 1200 1400
T-3
Ret
enti
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)
Tritium Retention in Graphite
NRL IFE 2/2001
• T-3 attaches to basal plane edges and highly defected structure. More perfect material and/or high temperature allows less retention.
First High Thermal Conductivity SiC/G Composite
• Matrix : CVI SiC • Fibers : Z-direction either Amoco P55 or Thornel K-1100 fiber X-Y direction P-55 fiber. Volume Fraction 44%.• Architecture : Unbalanced 1-1-6 weave 6 tows in Z-direction
Fiber K-1100 P-55 Nicalon Type-S
Kth (W/m-K@RT) ~950 120 15Diameter (micron) 10 10 13Tensile Strength (GPa) 3.1 1.9 2.6Tensile Modulus (GPa) 965 379 420Density (g/cc) 2.2 2.0 3.2
P55 fiber
K-1100 fiber
NRL IFE 2/2001
High Thermal Conductivity SiC/G Composites
0
50
100
150
200
250
300
350
0 1 2 3 4 5 6Deflection (mm)
3 x 4 x 50 mm
19 mm
38 mm
CVI SiC/K-1100,P-55 fiber unbalanced weave compositeMajor fiaber axis || to tensile axis
• Mechanical performance comparable to that of SiC/SiC composites.
• Further development will likely yield improved properties.
• Total of 9 tests on CVI SiC/K1100 fiber
Ultimate Bend Strength 283 ± 30 MPa
Macroscopic Matrix Microcracking ~130 MPa
NRL IFE 2/2001
High Thermal Conductivity SiC/G Composite- infiltration -
• Good inter-bundle infiltration (5-8% void) • Large intra-bundle porosity (13% void)
P
55
P55 tow
P55 tow
NRL IFE 2/2001
High Thermal Conductivity SiC/G Composites- tritium retention -
10
100
1000
104
0 20 40 60 80 100
UnirradiatedNeutron Irradiated
Hydrogen Solubility (appm)
Graphitic Perfection (%)
1
10
100
1000
104
0.001 0.01 0.1 1 10
N3M graphiteFMI-222 CFCMKC-1PH CFC
Tritium Retention (appm)
Radiation Damage (dpa)
• Tritium retention, non-irradiated and irradiated, is highly dependent on graphite perfection. K-1100 type fibers are nearly perfect.
Atsumi dataTirr=600°C
Tload=1000°C
Tirr=200°C
Tload=1000°C
NRL IFE 2/2001
Causey/Sneaddata
High Thermal Conductivity SiC/G Composites - thermal conductivity -
0
50
100
150
200
250
300
350
400
0 200 400 600 800
Th
erm
al C
on
du
ctiv
ity
(W/m
-K)
Temperature (C)
SiC/SiC Composite (transverse)
P55 Graphite/CVI SiC (high TC)
Morton CVD SiC
K1100 Graphite/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
NRL IFE 2/2001
0
50
100
150
200
250
300
350
400
0 200 400 600 800 1000
Th
erm
al C
on
du
ctiv
ity
(W/m
-K)
Temperature (C)
CVD SiC/K1100 Non-Irradiated
CVD SiC/K1100 Irradiated
CVD SiCNon-Irradiated
CVD SiC Irradiated
High Thermal Conductivity SiC/G Composites - thermal conductivity -
• At IFE-relevant temp., SiC matrix / graphite fiber :
--> irradiated TC exceeds maximum for SiC
--> exceeds SOMBRERO assumptions
• irradiated values are empirically determined
NRL IFE 2/2001
Future Efforts in Area of IFE Materials
• Continue and complete METS experiment to define high temperature swelling and thermal conductivity of advanced CFC’s.
• Expand work to include tritium retention and second generation materials. Develop data-base for designers.
• Complete thermal defect model for conductivity prediction.
• Continue low-level development of SiC/graphite system. Include piggy-back irradiation experiment and tritium retention measurement.
• Offer collaborative irradiation-effects study in HFIR low-dose, low-cost rabbit facility.
• Leverage current MFE modeling effort and ceramic/diagnostic programs.
NRL IFE 2/2001