General Comments on the
Development of Future Fusion PFCs
presented by
Richard E. Nygren
Sandia National Laboratories
ARIES High Heat Flux Components Workshop
UCSD 10-12 December 2008
RE Nygren, Sandia
Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company,
for the United States Department of Energy’s National Nuclear Security Administration
ARIES Town
Hall
- 10-12dec2008
- UCSD
under
contract
DE-AC04-94AL85000.
BROAD SCOPE
Tokamak/AT
Focus: 1. tokamak divertors
2. solid surface PFCs
3. present/ITER-DEMO gap
Alternates
Other: 4. alternates
5. liquid surface
6. other fusion pathways
RE Nygren, Sandia
ARIES Town Hall - 10-12dec2008 - UCSD
BROAD SCOPE
Tokamak/AT
ITER
divertor
JET
JT-60U DIII-D
C-MOD
TEXTORASDEX-U
TFTR
Tore Supra
Alternates
MAST
NSTX
LHD
W7X
Wendelstein
Non-electric or hybrid applications
RE Nygren, Sandia
ARIES Town Hall - 10-12dec2008 - UCSD
BROAD SCOPE
Tokamak/AT
ITER
divertor
JET
JT-60U DIII-D
C-MOD
???
TEXTORASDEX-U
TFTR
???
DEMO-A
DEMO-B
divertor
divertor
Tore Supra
Alternates
???/CTF
MAST
NSTX
???
LHD
???
W7X
?? primary
alternate
Wendelstein
Non-electric of hybrid applications
RE Nygren, Sandia
ARIES Town Hall - 10-12dec2008 - UCSD
BROAD SCOPE
Tokamak/AT
JT-60U DIII-D
C-MOD
???
TEXTORASDEX-U
TFTR
DEMO-A
DEMO-B
divertor
divertor
ITER
divertor
JET
???
D/T plasma
Tore Supra
solid surface
long pulse
good efficiency
high availability
damage resistance
Alternates
???/CTF
MAST
NSTX
?? primary
???
alternate
LHD
???
W7X
?liquid surface
Wendelstein
Non-electric of hybrid applications
RE Nygren, Sandia
ARIES Town Hall - 10-12dec2008 - UCSD
WORKSHOP SCOPE
Tokamak/AT
JT-60U DIII-D
C-MOD
???
TEXTORASDEX-U
TFTR
DEMO-A
DEMO-B
divertor
divertor
ITER
divertor
JET
???
D/T plasma
Tore Supra
solid surface
long pulse
???/CTF
tritium retention
active cooling
GAP 1
RE Nygren, Sandia
good efficiency
high availability
damage resistance
high temperature
high reliability
neutron damage
GAP 2
ARIES Town Hall - 10-12dec2008 - UCSD
WORKSHOP SCOPE
 active cooling
 tritium retention
GAP 1
RE Nygren, Sandia
 high temperature
 high reliability
 neutron damage
GAP 2
ARIES Town Hall - 10-12dec2008 - UCSD
OTHER SCOPE
Tech.
Alt’s.
physics
GAP X
 active cooling
 tritium retention
GAP 1
RE Nygren, Sandia
tokamak
GAP Y
 high temperature
 high reliability
 neutron damage
GAP 2
ARIES Town Hall - 10-12dec2008 - UCSD
SOURCES
Tokamak/AT
ITER
divertor
JET
JT-60U DIII-D
C-MOD
???
TEXTORASDEX-U
TFTR
???
DEMO-A
DEMO-B
divertor
divertor
Tore Supra
D Maisonnier et al.,
DEMO and Fusion Power Plant
Conceptual Studies in Europe
Nucl. Fusion 47 (2007) ISFNT7
G Federici et al.,
Key ITER plasma edge and plasma–material
interaction issues, JNM 313–316 (2003) PSI
J Linke et al.,
High heat flux testing of plasma facing
materials …, JNM 367–370 (2007)
RE Nygren, Sandia
K. Lackner SOFT2006
V Philipps
Plasma–wall interaction, a key issue on the way to a steady
state burning fusion device, Phys. Scr. T123 (2006)
ARIES Town Hall - 10-12dec2008 - UCSD
Sources
Tokamak/AT
ITER
divertor
JET
JT-60U DIII-D
C-MOD
???
TEXTORASDEX-U
TFTR
Tore Supra
???
“Greenwald” Panel Report
Priorities, Gaps and Opportunities: Towards A Long-Range
Strategic Plan For Magnetic Fusion Energy, FESAC Oct 2007
D Whyte
The Challenges of Plasma-Surface Interactions
for ITER & Beyond, to FESAC Nov 2008
G Federici et al.,
Key ITER plasma edge and plasma–material
interaction issues, JNM 313–316 (2003) PSI
J Linke et al.,
High heat flux testing of plasma facing
materials …, JNM 367–370 (2007)
RE Nygren, Sandia
DEMO-A
DEMO-B
divertor
divertor
US ReNew
Activity
D Maisonnier et al.,
DEMO and Fusion Power Plant
Conceptual Studies in Europe
Nucl. Fusion 47 (2007) ISFNT7
K Lackner SOFT2006
V Philipps
Plasma–wall interaction, a key issue on the way to a steady
state burning fusion device, Phys. Scr. T123 (2006)
ARIES Town Hall - 10-12dec2008 - UCSD
“Greenwald” Panel Report
“The themes were defined in terms of knowledge required prior to Demo.
... based on sound scientific principles and rigorously tested in the laboratory
so that the step to a [DEMO] .. taken with high confidence of success.
RE Nygren, Sandia
ARIES Town Hall - 10-12dec2008 - UCSD
“Greenwald” Panel Report
“The themes were defined in terms of knowledge required prior to Demo.
... based on sound scientific principles and rigorously tested in the laboratory
so that the step to a [DEMO] .. taken with high confidence of success.
Theme B. Taming the Plasma Material Interface:
.. knowledge sufficient to design and build, with high confidence,
8. PWI: Understand and control of all processes that couple the
plasma and nearby materials.
9. PFCs: Understand .. materials and processes that can be used
to design replaceable components that can survive ..
10. .. Other .. : .. necessary understanding of plasma interactions,
neutron loading and materials to allow design of .. any other
diagnostic equipment that can survive ...
RE Nygren, Sandia
ARIES Town Hall - 10-12dec2008 - UCSD
“Greenwald” Panel Report
Theme C. Harnessing fusion power:
knowledge .. sufficient to design and build, with high confidence,
11. Fuel Cycle: .. manage the flow of tritium ...
12. Power: .. temperatures sufficiently high for efficient production
of electricity or hydrogen.
13. Materials ..: Understand the basic materials science for fusion
breeding blankets, structural components, plasma diagnostics
and heating components .. high neutron fluence ..
14. Safety: Demonstrate .. safety ….
minimize environmental burdens ..
15. RAMI [Reliability, Availability, Maintainability & Inspectability]:
Demonstrate .. productive capacity ….
validate economic assumptions ….
RE Nygren, Sandia
ARIES Town Hall - 10-12dec2008 - UCSD
“Greenwald” Panel Report
Finding 6. Evaluation of current and planned
programs and summary of gaps
….. The most significant gaps were: G1. …. G2. …
G-5. Ability to predict and avoid, or detect and mitigate,
off-normal plasma events …
G-9. Sufficient understanding of all plasma-wall interactions ….
The science underlying the interaction of plasma and
material needs to be significantly strengthened to ..
G-10. Understanding of the use of low activation solid and liquid
materials, joining technologies and cooling strategies ...
G-11. Understanding .. the complete fuel cycle, particularly ..
G-12. An engineering science base .. effective removal of heat ...
G-13. Understanding .. low activation materials ..
G-14. .. guarantee safety over the plant life cycle - including ..
G-15. .. efficient maintainability of in-vessel components ..
RE Nygren, Sandia
ARIES Town Hall - 10-12dec2008 - UCSD
“Greenwald” Panel Report
Recommendation 4. .... nine major initiatives.
I-1. .. predictive plasma modeling and validation ..,
I-2. Extensions to ITER AT capabilities .. burning AT regimes
I-3. Integrated advanced burning physics …facility .. dedicated
I-4. Integrated experiment for PWI/PFCs .. steady-state .. non-DT
I-5. .. disruption-free concepts .. performance extension device ..
I-6. .. advanced computer modeling and laboratory testing ..
single-effects science for major fusion technology issues,
I-7. Materials qualification facility … (IFMIF).
I-8. Component development/testing program … multi-effect
issues in critical technology .. breeding/blanket .. first wall
I-9. Component qualification facility.. high availability.. heat
flux .. neutron fluence .. DT device .... (CTF).
RE Nygren, Sandia
ARIES Town Hall - 10-12dec2008 - UCSD
D Whyte FESAC Presentation
“The Challenges of PSI for ITER & Beyond” Nov 2008
tokamaks
now
Issue/Gap
 Quiescent energy exhaust
 Transient energy exhaust from
plasma instabilities
 Yearly neutron damage in
plasma-facing materials
 Max. gross material removal
rate with 1% erosion yield
 Tritium consumption
RE Nygren, Sandia
ARIES Town Hall - 10-12dec2008 - UCSD
ITER
CTF
DEMO
D Whyte FESAC Presentation
“The Challenges of PSI for ITER & Beyond” Nov 2008
 Lack basic understanding and diagnosis of PSI processes in








fusion devices → Uncertain extrapolation
Heat exhaust is primary design point for edge materials, since this
Is directly related to fusion power density
Thermal efficiency .. high ambient T → Fundamentally different
Physical Chemistry .. completely unexplored in fusion devices
Energy sustainment chasm to CTF & DEMO
Rapid dissipation of plasma thermal energy poses major
challenges in any Demo
consequences of large particulate removal on .. plasma .. & safety
Tokamak edge plasmas feature extreme spatial gradients and
fluctuations levels, .. erosion prediction & control very difficult
It is hard to overstate the importance of ambient temperature for
fuel control & T retention
30+ years of experience .. we should be worried/excited ..
in particular the effects of having “hot walls”
RE Nygren, Sandia
ARIES Town Hall - 10-12dec2008 - UCSD
Power plant conceptual studies in Europe
RE Nygren, Sandia
ARIES
Town Hall - 10-12dec2008
- UCSD
D. Maisonnier,
D. Campbell,
I. Cook, Nucl.
Fusion 47 (2007) 1524–1532 [ISFNT7]
Power plant conceptual studies in Europe
RE Nygren, Sandia
ARIES
Town Hall - 10-12dec2008
- UCSD
D. Maisonnier,
D. Campbell,
I. Cook, Nucl.
Fusion 47 (2007) 1524–1532 [ISFNT7]
Power plant conceptual studies in Europe
RE Nygren, Sandia
ARIES
Town Hall - 10-12dec2008
- UCSD
D. Maisonnier,
D. Campbell,
I. Cook, Nucl.
Fusion 47 (2007) 1524–1532 [ISFNT7]
Power plant conceptual studies in Europe
RE Nygren, Sandia
ARIES
Town Hall - 10-12dec2008
- UCSD
D. Maisonnier,
D. Campbell,
I. Cook, Nucl.
Fusion 47 (2007) 1524–1532 [ISFNT7]
High temperature
He-cooled divertor
Need for work on
divertor systems
RE Nygren, Sandia
ARIES Town Hall - 10-12dec2008 - UCSD
Whose DEMO?
In contrast to the rest of the world,
a typical preference of US technology people has been
 one step to high tech DEMO (reactor prototype)
 parallel R&D for materials and blankets (CTF)
RE Nygren, Sandia
ARIES Town Hall - 10-12dec2008 - UCSD
Whose DEMO?
In contrast to the rest of the world,
a typical preference of US technology people has been
 one step to high tech DEMO (reactor prototype)
 parallel R&D for materials and blankets (CTF)
We have a great challenge to develop the needed technology!
ITER activity is a revealing as we observe
the need for definition and integration in the design
along with the need to move forward in building the machine!
RE Nygren, Sandia
ARIES Town Hall - 10-12dec2008 - UCSD
We develop PFCs using single effects tests
RE Nygren, Sandia
J. Linke
et al.,
(2007)
1422–1431
ARIES
TownJNM
Hall -367–370
10-12dec2008
- UCSD
We love issues
We are good at developing issues
We tend to
 be optimistic (we are in fusion after all)
 enjoy identifying issues and pondering problems
 look toward R&D programs
RE Nygren, Sandia
ARIES Town Hall - 10-12dec2008 - UCSD
GAP 3: Technology Culture
M a t ’l s d e v el o p m e n t
We develop
PWI & PFC tests
one-of-a kind units
component dev./qual
with anecdotal mockup tests.
PWI
tests
PFC
tests
tokamak coupons
test PFC
lab tests
lab tests
rad effects testing
properties
properties 2
Material A
mockups
prototypes
prototypes
joining
tests
tests
tests
Material B
Material A
scale up
manufacturing
manufacturing
components
Vendor qual.
acceptance
development
design validation
QA development
RE Nygren, Sandia
ARIES Town Hall - 10-12dec2008 - UCSD
GAP 3: Technology Culture
M a t ’l s d e v e l o p m e n t
PWI & PFC tests
component dev./qual
Configuration d e v e l o p m e n t
STs, others
Ergodic div.
Super-X div.
Liquid PFCs
A realistic “fully funded” technology program,
will involve a strong winnowing of choices
for PFC materials and divertor technology
simply because of the time to develop and prove
specific robust components for a DEMO.
RE Nygren, Sandia
ARIES Town Hall - 10-12dec2008 - UCSD
PROGRAM & DESIGN INTEGRATION
knowledge .. sufficient to design and build, with high confidence,
Recall some excerpts from the “Greenwald” panel report:
9. PFCs: Understand .. materials and processes … design
replaceable components that can survive ..
I-3. Integrated advanced burning physics …facility .. dedicated
I-4. Integrated experiment for PWI/PFCs .. steady-state .. non-DT
I-8. Component development/testing program … multi-effect
issues in critical technology .. breeding/blanket .. first wall
RE Nygren, Sandia
ARIES Town Hall - 10-12dec2008 - UCSD
END
RE Nygren, Sandia
ARIES Town Hall - 10-12dec2008 - UCSD