| Countries Currently Participating
in ITER through China, Europe, Japan, Korea, Russia, and the United
States
Austria, Belgium,
Canada, China, Czech Republic, Denmark, Finland, France, Germany,
Greece, Hungary,
Ireland, Italy, Korea, Japan, Kazakhstan, Luxembourg, Netherlands,
Portugal, Romania, Russia, Spain, Switzerland, Sweden, United States.
What
are the Benefits of U.S. Participation in ITER?
The
appropriateness of the investigation of burning plasma as the next step
for MFE research has been recognized by multiple internal and external
program reviews. By wide consensus, the tokamak is the only magnetic
approach
sufficiently mature to enter the burning-plasma regime. Even then, the
facility choices for a tokamak next step Burning Plasma
Science Experiment can be numerous, e.g., scientific
vs. scientific-plus-technological investigations and demonstrations;
short
vs. long-pulse operation; high-field, cryogenically-cooled copper vs.
superconducting magnets; conservative vs. advanced operating modes;
domestic
vs. international sponsorship; etc. It is the current view
that participation in ITER represents for the US both the most scientifically
valuable and cost effective approach to investigate burning plasmas has
been based on the following framework:
- Exciting
new science: ITER will likely be the principal MFE experiment
for US participation for the next 20—30 years. It will
address a broad range of science to garner interest and capture
the
imagination
of the fusion and the larger scientific communities. Most importantly,
it will have the experimental operation, the flexibility,
and
the measurement capability, as well as supporting theory and modeling,
needed to conduct a full scientific program.
- Scientific
and Technological Infrastructure: ITER contributes to
the US fusion energy scientific and technological infrastructure
as broadly as possible. It is a key step in the
development
of fusion power.
- Continuation
of Frontier Research: ITER is based on today’s
most up-to-date research, and is positioned to
advance that research in a timely way when it comes into operation
a decade
from now. In particular, the facility has the capabilities
to take advantage of advanced tokamak (AT) scenarios now being
developed
and to extend fully AT research into the burning plasma regime.
- Progress
on the Development Path of Fusion Energy: ITER will develop
the knowledge base for progression to a subsequent step, i.e.,
a
follow-on experiment or demonstration power plant.
- Contribute
to the Broader Fusion Scientific Base: Through the course
of MFE history, the tokamak has proved an essential contributor
to the
scientific
base upon which much of the non-tokamak research relies. ITER will
have the same components of a strong science program required
in
1) above.
- Full Community
Participation: ITER research should enable full
fusion community access and participation. This requires a
management
structure that addresses modes of access, run time, experimental
planning, data sharing, etc.
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Is
ITER an Appropriate Next Step?
The question of what is the appropriate major next step for the magnetic
fusion program has paralyzed its researches for nearly two decades.
There
is now a strong consensus that the next major scientific frontier is
to investigate and demonstrate burning plasmas. However, moving forward
has been thwarted
by inevitable uncertainties and options associated with any such new
venture. In addition scientists are concerned that launching a burning
plasma experiment
will slow research in allied research areas aimed at deepening scientific
understanding and exploring other magnetic configurations.
This is further complicated by political expectations and budget realities
that it should be undertaken internationally. Recently, after numerous
studies, committees, and review panels, the fusion community has concluded
that ITER is the best choice to explore the science of burning plasmas.
It is designed to most comprehensively address the scientific and technical
issues of a burning plasma relevant to an eventual power plant. It is
a step comparable to past steps that have advanced our field to it’s
present level.
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How
Does ITER Compare to a Vision of a Fusion Power Plant?
ITER’s physical characteristics are similar to those of a possible
future fusion power plant. Here we do not argue that the eventual fusion
power plant will necessarily look just like ITER, but rather that ITER
looks like today’s vision of a possible fusion power plant. Therefore
moving forward with ITER must not rule out research on other magnetic
configurations or research to deepen understanding of the complex behavior
of high
temperature
plasmas.
Fusion power plant system studies, such as ARIES-AT point to a tokamak
reactor being a steady state super conducting device like ITER, but with
20% higher toroidal magnetic field strength and with a comparable 13
MA
of plasma current. The ARIES-AT plasma dimensions are 25% smaller by
assuming more optimized plasma performance than demonstrated today. In
short ITER’s
physical characteristics are very similar to those of the ARIES-AT power
plant.
The big difference would be in the optimization and control of the plasma.
By optimization of the plasma current and pressure profiles the power
plant would operate at higher plasma pressure, and thereby produces 3.5
times more fusion power. The optimized power plant would operate with
almost all of it’s plasma current being self- driven so that the
fusion gain Q would be 50, resulting in a 51% net plant efficiency. Experiments
in ITER would explore such optimized operation, but much still needs
to
be learned and demonstrated in existing experiments to achieve such optimized
plasma control. These scientific investigations of the complex interactions
in a self heated plasma is what ITER will pioneer.
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How
Does ITER Compare to Today’s Fusion Experiments?
In the late 1970’s the world fusion program initiated the construction
of three large facilities JET, JT-60U, and TFTR in Europe, Japan, and
at Princeton. These experiments produced outstanding scientific results
that greatly advanced our field. The size of these steps was larger than
the today’s step to ITER.
In physical dimensions, ITER is twice the size of JET, JT-60U, and TFTR.
ITER’s magnetic field strength is similar to that of TFTR, but it’s
magnets are super conducting. ITER’s 6 T super conducting magnetic
field is 33% higher than that of French Tore-supra and 25% below that
of the small Japanese TRIAM-1M super conducting Tokamaks. To confirm
the ITER magnet design, a model toroidal coil and a solenoid coil were
built
and successfully tested. The most recent ITER design benefits from having
more triangularly than today’s large tokamaks. The larger size
and higher field enable ITER to operate with 15 MA of plasma current,
five
times more than in today’s largest tokamaks. The larger size and
current of ITER will increase plasma confinement and thereby increase
the fusion power twenty-fold to 400 MW and the energy gain from just
below
unity to ten.
To reach burning plasma temperatures, ITER will employ neutral beam,
electron cyclotron, and ion cyclotron heating systems. The power levels
of these
systems will total 73 MW initially for 400 second pulses with possible
upgrade options to double the power for sustained current driven steady-state
operation. The ITER heating system will be three to five times more powerful
than those in use today. ITER’s 400 second to steady state pulse
capability compares with 20 seconds in JET, 2 minutes in Tore-supra,
and 2 hours in TRIAM-1M 2 hours.
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How
Will ITER Organize, Plan, Conduct, and Report Research?
How the ITER research team would be organized, would plan, would conduct
research, and would report results will be defined by the parties that
participate in ITER construction.
The design of ITER-FEAT has been developed not only to satisfy plasma
performance requirements but also to have the flexibility of plasma operations
for studying burning plasma and for optimization of plasma performance
for various objectives. The first plasma is expected eight years after
the start of construction. Physics diagnostic instruments, improved theory
and analysis codes, and research scenarios would be developed during
this
construction phase. An outline ITER operation plan for the first ten
years has been developed. Operation
will begin with hydrogen (H) and progress to deuterium-tritium (DT).
A
review of results from the first ten years operation will determine the
second ten years plan that could emphasize physics optimization of overall
performance and testing of components, such as blankets, with higher
neutron
fluences.
Today one can conjecture that the research will be carried out building
on successful practices developed at collaborative fusion research facilities
such as at JET, DIII-D, C-mod, and NSTX, as well as at other large international
science programs such as EFDA and CERN. Each is organized appropriate
to its research objectives. The JET research program is now organized
under the European Fusion Research Agreement (EFDA).
Common to all the above examples are that each has a central team, each
has members from different countries, each has a research team from many
collaborating universities and laboratories, each has members who receive
funding from different sources, each engages students, post doctoral scientists,
and senior researchers. Each receives research proposals that are prioritized
and selected by scientific peer review. All have oversight and/or program
advisory committees whereby the broader community has input and influence
on the research program.
Each program seeks a balance between the coherence provided by a central
team with the stimulation and introduction of new ideas provided by outside
teams. Different programs today have struck this balance differently.
Each provides valuable experience in how best to organize such a large
and multi-party facility like ITER.
Also common to all these examples is that institution and individuals
participate differently. Some participate long term at the facility
site,
others for briefer visits. Some are involved with unique equipment and
diagnostic instruments at the site, while others participate at a distance
with analysis, theory, and modeling.
Over the years fusion research programs have been organized in different
ways, depending on program objectives and program elements as well as
the maturity of the facility. Variations by which fusion research have
been conducted include organization around:
- Multi-institutional
research thrust (e.g. at DIII-D for resistive wall mode plasma feedback
control, or at JET for Advance Tokamak)
- Multi-institutional
science topical areas (e.g. at NSTX by science topic, at TFTR for alpha
physics, at Alcator C-Mod for RF heating, etc…).
- Multi-institution
diagnostic teams (e.g. at DIII-D for advanced divertor plasma characterization).
— Equipment (e.g. at JET for pellet injection).
— Institutions (e.g. at DIII-D with U.S. and Japan teams).
These different
models strive to provide a scientific atmosphere with sufficient coherence
to speed progress with sufficient independence to foster innovation.
Fostering
scientific creativity requires an organization that rewards scientific
excellence and encourages competitive teamwork within a framework of
scientific
peer review. ITER will obviously choose and emerge into its appropriate
research organizational structure by adapting the advantages of the
various
options as appropriate for it’s different operating phases. For
example, in the beginning a focused effort to produce and develop the
initial plasmas
and commission the hardware and diagnostic complement will obviously
be high priority and later move toward a more research orientation
A concern among scientists is how the results of their research will
be reported. How these issues will
be dealt with during ITER research must be developed, just as with any
new program. One would anticipate that the best practices would be adapted
from operating large fusion science programs. Elements of such practices
include: select research topics with key individuals, provide
an equitable framework to reward ingenuity and effort, provide scientific
peer review, establish ground rules for release of data, encourage and
facilitate scientists to report results, etc.
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How
Will The Research Team be Structured Both Internationally and Domestically?
One might surmise that the research team would be structured similar
to past practices of the ITER physics unit. ITER Physics is organized
by
topical physics areas (e.g., Transport, Stability, etc.) as illustrated
in the “ITER Physics Basis” report. ITER Physics is also organized
around critical issues, as exemplified by R&D needs. The participating
ITER parties will determine the organization.
As has been past ITER practice, the international physics team will likely
consist of an on-site multi-national physics team augmented with visiting
scientists from the national parties. A guiding principle of the past
and current ITER physics team has been that leadership roles are apportioned
among the participating parties according to the scientific strength of
the individual available scientists.
ITER is expecting to have distributed physics control rooms located among
the parties to facilitate participation from ones home country. These
would be much more sophisticated than now in use in U.S. National Facilities.
They would employ technologies such as being developed by the U.S. Collaboratory
Program.
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How
Might University Groups and Individuals Participate in ITER Research?
ITER provides a unique opportunity to extend the science of high temperature
plasmas to the burning plasma physics regime and explore the complex
integrated
interactions with a tokamak configuration that is on the development
path toward fusion power. Results of this research will both enrich the
field
of plasma physics as well as provide applicable data for other fusion
concepts being investigated in many universities and laboratories. Insights
and understanding gained from these other concepts
will be of value to the ITER advanced tokamak program.
University faculty, researchers, and students
will have the opportunity to participate. The range of university research
could encompass extending current physics studies to reactor-scale burning
plasmas as well as evaluating and developing cutting edge technology.
Research could be carried out somewhat like programs at currently operating
international collaborative fusion programs such as at JET and other
facilities. For example, at DIII-D there are 355 users from 60 different
organizations,
including 20 Universities - many with students and postdoctoral fellows.
University groups lead elements of the research, develop specialized
diagnostic
equipment, innovate and extend theory and codes, analyze data, as well
as participate in developing new technologies. These university groups
are funded by grants directly from the DOE or by collaborative contracts.
On ITER university groups could be members or lead a U.S. team building
diagnostic systems.including data analysis, theory and modeling. Such
a team must have some staff on-site, but others could participate remotely.
In addition to direct participation in ITER, universities must play an
essential role in maintaining a broad and balanced fusion energy science
program that includes non-burning plasma experiments as well as advancing
theory, modeling, diagnostics, and data analysis to explore and develop
new understanding and concepts. These smaller scale experiments provide
sources of specialized scientific knowledge as well as providing a training
ground for students who could extend their research to burning plasmas
in ITER and eventually become the researchers and leaders of ITER and
subsequent fusion steps. Universities also provide intellectual cross-links
between the emerging understanding of ITER burning plasma physics to
new
concepts and advances in basic understanding. Such a role parallels the
strategy adapted by the U.S. high energy physics community.
Other options come from high-energy physics where there are about 4,000
U.S. particle physicists of which 80% are from universities. Consider
the CERN Large Hadron Collider in Switzerland. One of its detectors is
ATLAS, which is ITER size (20m diameter x 40 m long). ATLAS is carried
out as a collaboration between 34 countries, 150 universities and laboratories
with 2,000 scientists. The US ATLAS group consists of 27 universities
and 3 national laboratories; it comprises about 20% of the ATLAS institutions.
A feature of such collaborations is that they have democratic governing
boards, elected chair and spokespersons, in addition to line management.
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