Transcript PNNL SiC/SiC Test Blanket Module Contributions

PNNL SiC/SiC Test Blanket Module
Contributions
CH Henager, Jr.
GE Youngblood
RJ Kurtz
Pacific Northwest National Laboratory
Richland, WA
ITER-TBM Meeting
August 10-12, 2005
Idaho Falls, ID
April 10, 2016
Large, Geometrically Complex Structures
can be Readily Fabricated From SiC
Actively Cooled
Thrust Chambers
Misc. Components
Combustor Liners
April 10, 2016
Thermal Conductivity – Currently Too High
150
Thermal Conductivity (W/mK)
Monol ithi c CVD-SiC, 3.22 g/cc
T yr SA/PyC/PIP(A+B), 2.65 g/cc
T yr SA/PyC/PIP(A+B), 2.55 g/cc
T yr SA/PyC/FCVI-Si C, 2.67 g/cc
Hi-Nic/PyC/ICVI-Si C, 2.60 g/cc
Fusion Wi ndow
3D-T yr SA/CVI (Yamada)
100
50
FCI Goal
0
0
200
400
600
800
Temperature (oC)
April 10, 2016
1000
1200
Recent Electrical Conductivity Measurements
Composite Disk
Electrical Conductivity (S/m)
103
102
FCI Goal
101
100
SiC/SiC (in-plane)
type S fiber
CVD (Weber)
CVD (Bar N11)
CVD (Hi-purity Bar)
SiC/SiC (transverse)
-1
10
10-2
0
200
400
600
800
o
Temperature ( C)
SiC fibers
1000
Mechanical Properties

SiC/SiC composites are
tough and strong but…
Composite cracks
expose fibers.
 Fatigue due to thermal
pulses could pump
PbLi into composite
interior.
 Thermal gradients
allow vapor transport.
 Thermal stresses and
fatigue require study
and understanding.

April 10, 2016
Joining and Bonding

Joining is a critical technology
for ceramics and composites
Fabricated simple shapes in
complex structures
 Hermetic face plates for SiC/SiC
in critical environments
 Dissimilar materials issues in
radiation effects and
mechanical/chemical
compatibility
 Many methods for joining that
can be adapted for TBM needs

• Pre-ceramic polymer joints
• Displacement reaction joining
• Brazing
April 10, 2016
Reactive Joining of SiC
Using Ti3SiC2/SiC Composites

Joint between -SiC using displacement
reaction between TiC + Si (tape cast
powders) processed in argon at
1200˚C/30 MPa.

Strong bonding occurs due to Ti3SiC2 +
SiC forming during reaction. Note
interfacial carbides formed during the
reaction.

Joints are tough and strong since Ti3SiC2
phase exhibits plasticity under some
conditions.

Joints can be tailored using other metal
carbides reacting with Si.
April 10, 2016
-SiC
Ti 3SiC2/SiC joint -SiC
Interfacial
Carbides
Suggested Contributions to ITER TBM
Programs utilizing SiC/SiC

Transverse thermal conductivity measurements


Transverse and in-plane electrical conductivity measurements


TBM design dependent measurements
Design and measure low conductivity materials
Mechanics and environmental interactions
Thermal stress gradients and thermal fatigue
 PbLi vapor transport and crack growth effects


Joining and bonding
Sealing porous SiC/SiC with hermetic bond layer (design)
 Compatibility (stress, fracture, and environmental) in TBM


Modeling



April 10, 2016
All aspects of thermal and electrical properties
Radiation effects
TBM cracking, thermal fatigue, crack “pumping” of PbLi