The purpose of the APEX study is to identify and explore novel, possibly revolutionary, concepts for Chamber Technology that might in the near-term enable plasma experiments to more fully achieve their scientific research potential and in the long-term substantially improve the attractiveness of fusion as an energy source. The vision for the APEX study is to contribute toward achieving a more affordable and cost-effective fusion energy sciences research program, as well as toward a safer, more economical, and more environmentally friendly fusion energy product.
A key feature of the study is providing a research environment conducive to innovation with emphasis on understanding and advancing the underlying engineering and physics sciences as a prerequisite for innovation. The study covers conceptual design, modeling, and experiments for new and evolutionary ideas for the Chamber Technology.
The APEX study is being carried out by a multi-disciplinary, multi-institution integrated team. The team members are drawn from twelve US institutions that include universities, national laboratories, and industry. In addition, there is significant international participation by scientists from Germany, Japan, and Russia.
The composition of the APEX team and the study approach emphasize partnership between plasma physics and technology and strong interactions among the key technical areas and functional disciplines such as thermofluids, thermomechanics, magnetohydrodynamics, materials, plasma-material interactions, system studies, nuclear, and safety.
OFES Letter of Charge
Download a copy of the letter in pdf format.
July 16, 1997
Professor Mohamed Abdou
Dear Mohamed:
As you know, the ALPS effort is being organized to plan activities aimed
at evaluating high heat flux removal concepts that use liquids for plasma-facing
surface applications in divertors.
A more general issue for long-term attractiveness of fusion energy is
advanced concepts for extracting both high bulk heat flux and high surface
heat flux, which is necessary for power handling in fusion devices that
operate at high neutron wall loads.
Now is the time to undertake bold initiatives that might revolutionize
the way that we think about fusion power extraction and create a broad
design envelope for exploiting future gains in plasma performance.
Toward this end, I request that you organize and lead a group effort
to plan activities aimed at identifying and evaluating the feasibility
of advanced concepts capable of safe and efficient extraction of high bulk
and surface heat flux in fusion power cores operating at high neutron wall
loads.
Next-step concepts, such as ITER, have an average fusion core power
density that is over two orders-of-magnitude less than in present-day water
cooled fission reactors and a peak-to-average heat flux in the coolant
that is over an order-of-magnitude greater than in present-day water cooled
fission reactors. Longer-term concepts of an EVOLUTIONARY nature (i.e.,
based on ferritic steel, vanadium alloy, or silicon carbide composite structural
materials) may not be able to achieve the average fusion core power densities
and peak-to-average heat fluxes needed for competitive economics.
Along these lines, there should be an element of fusion research that
nurtures creativity and innovation toward exploring REVOLUTIONARY power
extraction concepts that may be of high technical risk, but have high payoff
performance characteristics, such as:
Emphasis should be given to advanced concepts that have applicability
to a broad spectrum of magnetic confinement approaches.
These activities should systematically consider all fusion core components
associated with power handling and extraction and should devise innovative
concepts that integrate these components into self-consistent design approaches
that consider particle exhaust, safety, and environmental issues.
Consideration should be given to plasma performance issues due to their
influence on surface heat flux distribution. In particular, means to reduce
peak-to-average surface heat flux on plasma-facing components should be
considered.
One of the goals of APEX research should be to determine the upper limits
of fusion power core operation through a combination of plasma physics
approaches that reduce peaking factors and innovative in-vessel component
designs that can handle high peak heat loads. This will require cooperation
between physicists and engineers and a bridging of the interface issues
between plasma performance and plasma energy extraction.
The following guidelines should be followed by the APEX planning group:
The group should consider opportunities for international collaborations
and make recommendations accordingly.
The group should establish appropriate interfaces with the ALPS effort
and the Advanced Design community.
A draft plan for the evaluation phase effort should be available for
OFES review by the end of October 1997. When finalized, the plan will guide
the implementation of APEX evaluation studies in FY 1998, subject to the
availability of OFES funds for such a purpose.
I appreciate your willingness to lead the APEX planning group in this
exciting endeavor.
Sam Berk
School of Engineering and Applied Science
43-133 Engineering IV
Box 951597
University of California, Los Angeles
Los Angeles, CA 90095-1597
BACKGROUND
In the "Strategic Plan for the Restructured U.S. Fusion Energy Sciences
Program", issued by OFES in August 1996, one of the three policy goals
supporting the program mission is to:
"Develop fusion science, technology, and plasma confinement
innovations as the central theme of the domestic program"
In October 1996, sixty members of the U.S. fusion community and OFES met
at a planning workshop to chart the future of the program. The report from
this workshop emphasized the need to "explore the scientific basis for
innovative technologies and materials options capable of achieving the
full potential of fusion energy" and recommended the following as a five-year
goal:
"Marked progress in the scientific understanding of technologies
and materials required to withstand high plasma heat flux and neutron wall
load"
Relative to this goal, the following specific deliverable was recommended:
"Identify and evaluate new high performance concepts
for advanced technology with high neutron wall load capability and
attractive safety and environmental features"
This deliverable recognizes that technologies for surface and bulk heat
flux extraction must advance considerably beyond near-term capabilities
in order to handle the high neutron wall loads expected for economically
competitive fusion energy systems.
Of course, research on evolutionary concepts must continue toward proof-of-principle
experimentation and determination of performance limits. The proposed research
on revolutionary concepts, which will be of more fundamental nature moving
toward feasibility assessment, will stimulate the conception of new ideas
that utilize fundamentally different approaches and offer order-of-magnitude
higher payoffs, even if the development risks appear high.
GUIDELINES
The APEX (Advanced Power EXtraction) planning group is requested to prepare
a draft plan for activities aimed at identifying and evaluating the feasibility
of advanced concepts capable of safe and efficient extraction of high bulk
and surface heat flux in fusion power cores operating at high neutron wall
loads.
To the extent possible, the group should estimate the costs required to
perform a complete and thorough set of activities in the evaluation phase
effort, as well as the costs associated with performing a reduced scope
set of activities that involves minimum levels of design and analysis and
addresses only key feasibility issues.
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Sincerely,
Team Leader for Technology Programs
Office of Fusion Energy Sciences
Office of Energy Research
U.S. Department of Energy