Report of the FESAC Panel on

A BURNING PLASMA PROGRAM STRATEGYTO ADVANCE FUSION ENERGY
Table of Contents
page2

Executive SummaryI.

The Grand Challenge of Fusion
I.A
Burning Plasma Science
I.B
The Development Path to Fusion Energy

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5
6

II.

Background

7

III.

Experimental Options
III.A Mission Statements by Proposers
III.B Scope of Projects
III.C Performance Projections
III.D Schedules and Costs
III.E Paths for Future Development

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9
10
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IV.

The Recommended Strategy
IV.A Basis for the Strategy
IV.B Major Recommendations

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V.

Prioritized Objectives for U.S. Participation in ITER

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References

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Appendices
19
A. Fusion Program Integration
20
B. Fusion Development Paths and the Burning Plasma Experiment 24
C. Potential U.S. Roles and International Aspects of Burning Plasmas 30
D. The Charge Letter
44
E. Panel Membership
46
F. Meeting Agenda
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A BURNING PLASMA PROGRAM STRATEGYTO ADVANCE FUSION ENERGYEXECUTIVE SUMMARY
Fusion energy shows great promise to contribute to securing the energy future ofhumanity. The risk of conflicts arising from energy shortages and supply cutoffs, as wellas the risk of severe environmental impacts from existing methods of energy production,
are strong reasons to pursue fusion energy now.
The world effort to develop fusion energy is at the threshold of a new stage in its
research: the investigation of burning plasmas. This investigation, at the frontier of thephysics of complex systems, would be a huge step in establishing the potential ofmagnetic fusion energy to contribute to the world’s energy security.
The defining feature of a burning plasma is that it is self-heated: the 100 million
degree temperature of the plasma is maintained mainly by the heat generated by thefusion reactions themselves, as occurs in burning stars. The fusion-generated alphaparticles produce new physical phenomena that are strongly coupled together as anonlinear complex system. Understanding all elements of this system poses a major
challenge to fundamental plasma physics. The technology needed to produce and control
a burning plasma presents challenges in engineering science similarly essential to thedevelopment of fusion energy.
Experimental study of a burning plasma has long been a goal of the U.S. sciencebased fusion energy program. There is an overwhelming consensus among fusion
scientists that we are now ready scientifically, and have the full technical capability, toembark on this step. The fusion community is prepared to construct a facility that willallow us to produce this new plasma state in the laboratory, uncover the new physics
associated with the fusion burn, and develop and test new technology essential for fusion
power.
Three options are presently under consideration as burning plasma experimental
facilities: the international ITER project, the U.S.-based FIRE project, and the Italian
IGNITOR project. All three are tokamaks, the most extensively studied magnetic
configuration. The projects are at different stages of development, and have different
mission scopes, time schedules, and costs. ITER is a power-plant scale facility with acomprehensive science and technology program. It has a well-developed engineering
design and negotiations for construction are underway. U.S. participation in ITER would
have substantial domestic benefits. FIRE is a smaller scale facility with a broad science
program. It has an advanced pre-conceptual design. International participation in FIRE
would provide substantial benefits. IGNITOR has a well-developed design and is moving
forward in Italy. Its operation would provide valuable insight into burning plasma
science, although it is not designed to be the sole burning plasma facility in the world.
Recognizing the opportunity before us, the Fusion Energy Sciences Advisory
Committee was charged by the Department of Energy to “recommend a strategy forburning plasma experiments.” A FESAC panel was convened for this purpose. The
recommendations of the Panel are based, in large part, on an extensive scientific2assessment of the three options by the 2002 fusion summer study, a two-week meeting of
280 fusion scientists, preceded by eight months of preparatory activity.
Given this background, the Panel has produced a strategy to enable the U.S. toproceed with this crucial next step in fusion energy science. The strategy was constructedwith awareness that the burning plasma program is only one major component in acomprehensive development plan for fusion energy. A strong core science andtechnology program focused on fundamental understanding, confinement configuration
optimization, and the development of plasma and fusion technologies is essential to therealization of fusion energy. The core program will also be essential to the successful
guidance and exploitation of the burning plasma program, providing the necessary
knowledge base and scientific work force.
The Panel recommendations are guided by the design options and considerations
presented above and by two primary findings:
ITER and FIRE are each attractive options for the study of burning plasma science.
Each could serve as the primary burning plasma facility, although they lead todifferent fusion energy development paths.
Because additional steps are needed for the approval of construction of ITER or
FIRE, a strategy that allows for the possibility of either burning plasma option isappropriate.

With this background, the Panel puts forth the following major strategy
recommendations.
Since ITER is at an advanced stage, has the most comprehensive science andtechnology program, and is supported internationally, we should now seek to join
the ITER negotiations with the aim of becoming a partner in the undertaking, withtechnical, programmatic and timing considerations as follows:
The desired role is that the U.S. participates as a partner in the full range ofactivities, including full participation in the governance of the project and theprogram. We anticipate that this level of effort will likely require additional
funding of approximately $100M/yr.
The minimum acceptable role for the U.S. is at a level of effort that would allow
the U.S. to propose and implement science experiments, to make contributions
to the activities during the construction phase of the device, and to have accessto experimental and engineering data equal to that of all partners.
The U.S. performs a cost analysis of U.S. participation and reviews the overall
cost of the ITER project.

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The Department of Energy concludes, by July, 2004, that ITER is highly likely
to proceed to construction and terms have been negotiated that are acceptable to
the U.S. Demonstrations of likelihood could include submission to the partner
governments of an agreement on cost-sharing, selection of the site, and a planfor the ITER Legal Entity.

Since FIRE is at an advanced pre-conceptual design stage, and offers a broad
scientific program, we should proceed to a physics validation review, as planned,
and be prepared to initiate a conceptual design by the time of the U.S. decision on
participation in ITER construction.
If ITER negotiations succeed and the project moves forward under terms
acceptable to the U.S., then the U.S. should participate. The FIRE activity should
then be terminated.
If ITER does not move forward, then FIRE should be advanced as a U.S.-based
burning plasma experiment with strong encouragement of international
participation.
If IGNITOR is constructed in Italy, then the U.S. should collaborate in the program
by research participation and contributions of related equipment, as it does withother major international facilities.
A strong core science and technology program is essential to the success of theburning plasma effort, as well as the overall development of fusion energy. Hence,
this core program should be increased in parallel with the burning plasma initiative.
A burning plasma science program should be initiated by the OFES with additional
funding in FY 04 sufficient to support this strategy.

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I. THE GRAND CHALLENGE OF FUSION
Fusion energy shows great promise to contribute to securing the energy future ofhumanity. The risk of conflicts arising from energy shortages and supply cutoffs, as wellas the risk of severe environmental impacts from existing methods of energy production,
are among the reasons to pursue fusion energy now.
Fusion energy release involves reactions in a very hot gas – a plasma – in which
two light atomic nuclei combine to form a heavier nucleus. Fusion is the vast energy
source that powers the sun and the stars. The raw material for producing the fusion fuels,
deuterium (a heavy form of hydrogen) and lithium (from which the fusion fuel tritium is
produced), are abundantly available to all nations for thousands of years. Plasmas that are
hotter than the core of the sun have been produced and confined by strong magnetic
fields in the laboratory. The fusion plasmas in our largest experimental facilities haveyielded more than 10 megawatts of fusion power for about 1 second. Dramatic advances
have been made in recent years in the understanding and control of such plasmas. Thus
the challenge before us now is to make fusion energy practical.
Developing fusion as a source of energy is an exciting scientific and technological
grand challenge. The science that underlies this quest is at the frontier of the physics ofcomplex systems and contributes to the description of some 99% of the visible universe.
The progress made in all areas of fusion energy research in the past decade, and thegrowing realization that the world must take action now to meet our long-term energy
needs have set the stage for accelerating the development of practical fusion energy. Thisis recognized in the U. S. National Energy Policy released last year: “Fusion – the energy
source of the sun – has the long range potential to serve as an abundant and clean sourceof energy.”
I.A Burning Plasma Science
A burning plasma is a crucial and missing element in the world fusion program.
The defining feature of a burning plasma is that it is sustained largely by the heatgenerated through its own internal fusion reactions. This is in contrast to previous
experiments in which most of the heating was applied from outside the plasma. Whenthese reactions occur in a fusion power system, energetic alpha particles (helium nuclei)
and neutrons are generated. The alpha particles are confined by the magnetic field andslow down, transferring their energy to maintain the high temperature of the plasma.
When fusion alpha heating dominates the plasma dynamics, important new scientificfrontiers will be crossed. To create a burning plasma on Earth and systematicallydetermine its properties will be an enormous step forward for fusion energy research. It
will enable major advances in all of the key areas of plasma science and technology, andcontribute to the demonstration of magnetic fusion as a source of practical energy.
While delivering the fusion-sustaining heat, the alpha particles also represent a
new dynamic source of energy to change the plasma pressure profile. Such changes in theplasma structure and dynamics can increase the loss of heat and particles from theplasma, and consequently to a reduction in fusion power. Alternatively, these may lead toa further increase in temperature and fusion power production. Understanding andmodifying these effects on heat and particle transport, the subject of “burn control,” areessential elements of power plant development.
5Any magnetically confined burning plasma system must necessarily have a large
value of the magnetic field multiplied by the system-size so that the energetic particles,
produced by fusion reactions in the plasma, can be well confined. Ions gyrating aroundthe magnetic field in such a system follow nearly circular “gyro-orbits,” and the ratio of
the system size to the gyro-radius will enter a new regime in such an experiment. Thisratio is a key parameter governing plasma turbulence, and a burning plasma will also
open up new science in plasma turbulence. Furthermore, the fusion alpha particles candrive Alfvén waves (first discovered in an astrophysical context), and in a burning plasma
system new wave structures are possible which were not accessible in previous
experiments. The effect of populations of energetic particles on large-scale plasma
instabilities, analogous to solar flares, also enters a regime of new physics. Finally,
because of the very strong heat and particle fluxes emerging from a burning plasma, andthe influence of escaping alpha particles on energy deposition on the surrounding walls,
burning plasma research will extend regimes of plasma-boundary phenomena wellbeyond previous experience.
Each of these phenomena individually is at the forefront of high temperatureplasma physics. But perhaps the most challenging scientific aspect of a burning plasma is
the strong coupling between the phenomena. Research on burning plasmas will be at theforefront of the study of complex systems and nonlinear dynamics, building on recent
advances in theory and simulation. Exploring the properties and dynamics of a burning
plasma will be a fundamental and profoundly exciting scientific challenge, generating
broad intellectual benefits. Beyond its tremendous value to the development of practicalfusion energy, achieving this state of matter – a self-heated “star” in the laboratory –will
be a magnificent scientific achievement.
A burning plasma experiment will also provide unique opportunities to advancethe development of technologies and the engineering database for follow-on devices
needed for commercial power production. Plasma facing components will be pressed topreviously unexplored limits in heat flux and neutron fluence. A whole class of important
technologies needed for heating and fueling plasmas, as well as for driving plasma
current, and for remote maintenance of fusion systems will be brought up to the nextlevel of development.
This exciting next step to explore burning plasmas is an essential element in the
Fusion Energy Sciences Program whose mission is to “advance plasma science, fusion
science and fusion technology—the knowledge base needed for an economically andenvironmentally attractive fusion energy source.” The study of burning plasmas will be
carried out as part of an overall program that must include advancing fundamental
understanding of the underlying physics through theory and computational simulation,
optimization of magnetic confinement configurations and development of low activationmaterials and fusion technologies.
I.B The Development Path to Fusion Energy
The development path to realize fusion power as a practical energy source from a
toroidal magnetically confined plasma requires progress in three major areas in addition
to the element of burning plasmas:• Fundamental understanding of the underlying science: Dramatic advances have been
made in the last decade both through more sophisticated plasma diagnostic
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measurements and through the greatly enhanced computational power now available
to researchers. These efforts are essential because ultimately only a well-understoodand fully controlled plasma can function as a reliable fusion power source. In its
recent review of the fusion energy sciences program, the NAS/NRC endorsed thehigh quality of the scientific research in fusion and particularly emphasized thecritical importance of science in attaining the goal of practical fusion power.1• Optimization of the magnetic confinement configuration: Because the configurationof the magnetic field confining the fusion plasma has important implications for thepractical realization of fusion power, configuration optimization must be pursued inparallel with the study of a burning plasma in order to be prepared for the step to apractical demonstration power plant. These optimization studies are based on, andcontribute to, the fundamental understanding of high temperature plasmas. The
Secretary of Energy Advisory Board, in its recent review of the fusion energy
sciences program, highlighted the importance of pursuing this scientific element toassure the practicality of fusion energy.2• Development of low-activation materials and fusion technologies: It will be necessary
to develop and qualify environmentally and economically attractive materials forfusion application. Testing of the major technologies required for fusion will be
provided both through the burning plasma facility and through neutron source test
facilities designed to provide additional data on materials and component reliability,
availability and maintainability.
Pursuing these scientific elements implements the three policy goals for the restructured
science-based fusion energy program defined by the fusion community and FESAC in
1996: (i) Advance plasma science in pursuit of national science and technology goals; (ii)Develop fusion science, technology, and plasma confinement innovations as the central
theme of the domestic program; and (iii) Pursue fusion energy science and technology as
a partner in the international effort. Recent fusion program emphasis has been on making
progress in the first two of these scientific elements. However, the dramatic progress
made in fusion energy research in the past decade, and the growing realization that theworld must take action now to meet our long-term energy needs, has set the stage for
initiating the study of the crucial and now missing element of burning plasmas in thedevelopment of practical fusion energy.
II. BACKGROUND
The necessity for a burning plasma program has been recognized for many years,
and called for by the FESAC restructured Fusion Energy Sciences program of 1996. The
recent resurgence of interest in moving forward with the study of burning plasmas was
manifest by the initiation in 2000 of a series of burning plasma workshops sponsored by
the University Fusion Association, involving fusion scientists from national laboratories,
industry and universities.
Following these workshops, a FESAC panel was convened in 2000 to review
burning plasma physics and to recommend a direction for studies underway assessing
next step options.3 Among its recommendations, that panel concluded that NOW is thetime for the U.S. to take the steps leading to construction of a burning plasma experiment,7

that the funding for the experiment should be an addition to the core fusion energy
science budget, and that the U.S. should establish a proactive plan on burning plasma
experiments (and not assume a default position of waiting to see what the international
community may or may not do regarding the construction of a burning plasma
experiment).
The FESAC panel also recommended three steps for the fusion community tobring the U.S. fusion program toward formulating a strategy for burning plasmas. First, a
uniform technical assessment should be performed of the three present experimental
options: IGNITOR, FIRE, and ITER. Second, a “Snowmass-style” workshop should beheld in summer, 2002, in which the community assesses the scientific and technicalviability of each of the three options, and affirms (or denies) the proposition that the timeto proceed with a burning plasma experiment is now, not some undefined time in the
future. Third, a FESAC “action” panel should be convened to chart the future U.S. courseof action with respect to a burning plasma experiment. The first two activities have been
completed. The 2002 Fusion Summer Study held in Snowmass, CO, completed theuniform technical assessment and demonstrated essentially unanimous and enthusiastic
endorsement of the proposition that the fusion research community is ready, and now is
the time, for this next step in fusion energy science research.4
The conclusions of the 2002 Fusion Summer Study were based on analysis led byover 60 conveners working with hundreds of members of the fusion energy sciences
community extending over 8 months. This effort culminated in two weeks of intense
discussion by over 250 US and 30 foreign fusion physicists and engineers covering all
avenues of fusion energy research. The 2002 Fusion Summer Study assessment forms thescientific basis that has enabled the Panel to recommend a strategy. The present FESAC
panel serves the role of the “action” panel. The conclusions and recommendations
presented in Section IV are consistent with the earlier results of the FESAC Review of
Burning Plasma Physics and with the 2002 Fusion Summer Study results.
The purpose of the 2002 Fusion Summer Study was to assess the options for the
exploration of burning plasmas. The Study was not intended to, and did not, devise thebest path or strategy to pursue these burning plasma options. That is the goal of thepresent FESAC panel.
The charge to the present panel is “to recommend a strategy for burning plasma
experiments” (the full charge letter is contained in Appendix D). In developing thestrategy we have considered carefully all three burning plasma options investigated at the2002 Fusion Summer Study, making extensive use of the conclusions and findings of that
Study.
As the US has evolved in its assessment of next step burning plasma options,significant activity has been underway simultaneously in the international fusion energy
research program. In particular, the ITER burning plasma option has been moving
forward with negotiations for possible construction by four partners: Canada, theEuropean Union, Japan, and Russia. The engineering design of a reduced-size ITER
device has been completed, four potential sites have been identified, and a schedule has
been laid out that would lead to site selection and completion of negotiations in the nearterm. The engineering design of IGNITOR, which is moving forward in Italy, is also
complete. Finally, with the completion of an advanced pre-conceptual design of the

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U.S.-based FIRE burning plasma experiment, information is in hand for the formulationof a decisive strategy.
Since its inception, fusion energy science research has been a paradigm forinternational collaboration. Throughout its history, fusion research has been a stronglyinteracting, closely-knit international program. In implementing the third policy goal of
the Fusion Energy Sciences Program (to…pursue fusion energy science and technology
as a partner in the international effort), this will surely be a key property of any burning
plasma science program.

III. EXPERIMENTAL OPTIONSOver the past year, the US community conducted a uniform technical assessment(here referred to as the Study) of three approaches, IGNITOR, FIRE, and ITER, that havebeen proposed to investigate burning plasmas. The Study identified the key scientific andtechnological burning plasma issues and opportunities and made assessments of theabilities of the three approaches to address them. As the Study’s work has guided the
predominant views of our panel, we present below a summary of their report.
III.A Mission Statement by Proposers:
The following mission statements were adapted from statements provided by the
proposing teams to the Study.
•

IGNITOR is a facility whose mission is to achieve fusion ignition conditions indeuterium-tritium plasmas for a duration that exceeds the intrinsic plasma physics
time scales. It utilizes high-field copper magnets to achieve a self-heated plasma
for pulse lengths comparable to the plasma current redistribution time. IGNITOR
will study the physics of the ignition process and alpha particle confinement aswell as the heating and control of a plasma subject to thermonuclear instability.

•

FIRE is a facility whose mission is to attain, explore, understand and optimize
magnetically confined fusion-dominated plasmas. FIRE would study burning
plasma physics in conventional regimes with Q (the ratio of fusion energy output
power to the externally applied power heating the plasma) of about ten and highbeta advanced tokamak regimes with Q of about five under quasi-stationary
conditions. FIRE employs a plasma configuration with strong plasma shaping,double-null poloidal divertors, reactor level plasma exhaust power densities andpulsed cryogenically cooled copper coils as a reduced cost approach to achieve
this mission.

•

The overall objective of ITER is to demonstrate the scientific and technologicalfeasibility of fusion energy. ITER would accomplish this objective bydemonstrating extended burn of deuterium-tritium plasmas with Q at least ten,with steady-state as an ultimate goal, by demonstrating technologies essential to areactor in an integrated system, and by performing integrated testing of high heat
flux and nuclear components required to utilize fusion energy for practical
purposes. ITER also aims at producing nearly steady-state plasma regimes with9

Q greater than five, and the possibility to demonstrate controlled ignition definedas Q of about thirty.
III.B Scope of Projects
1. Points in Common
The Study concluded that each approach would enable the investigation of thephysics of burning plasma, advance fusion technology, and contribute to the developmentof fusion energy. IGNITOR, FIRE, and ITER would each make significant contributions
to burning plasma physics and technology.
•

Physics scope would include strongly-coupled physics issues of equilibrium,
stability, transport, wave-particle interactions, fast ion physics, and boundary
physics in the regime of dominant self-heating.

•Technology scopes would include (a) plasma support technologies (heating, fueldelivery, exhaust, plasma-facing components, and magnets) at parameters andplasma conditions close to those required for power production, and (b) nuclear
technologies (remote handling, vacuum vessel, blankets, safety and materials)
gained as a result of the experience of operating in a nuclear environment. The
levels of technological benefit from the approaches will depend on tritium
inventory, pulse length, duty factor, and lifetime fluence.

2. Differences in Opportunity
While all three approaches would make significant scientific and technologicalcontributions in these physics and technology areas, the opportunities offered by theapproaches are quite different. The Study clarified the following distinctions between theopportunities:•

IGNITOR offers an opportunity for the early study of burning plasmas aiming at
ignition for about one plasma current redistribution period.

•

FIRE offers an opportunity for the study of burning plasma physics inconventional configurations for a few plasma current redistribution time periods
and in advanced tokamak configurations under quasi-stationary conditions(several plasma current redistribution time periods), and would contribute toplasma technology.

•

ITER offers an opportunity for the study of burning plasma physics inconventional configurations for a few plasma current redistribution time periods
and in advanced tokamak configurations for long durations (many current
redistribution time periods) with steady state as the ultimate goal, and would
contribute to the development and integration of plasma and fusion technology.

3. Range of Studies
The benefits of the specific proposal beyond the ones common to all three approaches
are:

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•

IGNITOR would especially study two physics topics: (a) the science of selfheated plasmas in a power plant relevant regime of small ρ* (the ratio of the ion
gyro-radius to the plasma’s minor radius) for globally magnetohydromagnetic(MHD) stable plasmas at low βN (normalized ratio of plasma pressure to magnetic
field pressure), and (b) sawtooth stability at low beta with isotropic alpha particles
and self-consistent pressure profile determined by dominant alpha heating.
Technology scopes would include development of (a) high-field copper magnets
with advanced structural features, and (b) high-frequency RF antennas for wave
heating in a burning plasma environment.

•

FIRE would especially address three physics areas: (a) the science of self-heatedplasmas in power plant relevant regimes of small ρ* and high βN with a large
fraction of non-inductively driven current sustained for up to a few plasma current
relaxation times, (b) exploration of high self-driven plasma current regimes withstrong shaping and active MHD stability control, and (c) study of removal ofhelium ash and impurities with exhaust pumping. Technological scopes would
include development of (a) electrical insulation for high-field pulsed copper
magnets in a high neutron fluence environment, and (b) high heat flux plasmafacing components with such materials as tungsten and beryllium that will havesteady-state heat removal capability.

•

ITER would especially address four physics areas: (a) the science of self-heatedplasmas in power plant relevant regimes of small ρ* and high βN, and with thecapability of full non-inductive plasma current drive sustained in near steady state
conditions, (b) exploration of high self-driven plasma current regimes with aflexible array of heating, current drive, and rotational drive systems, (c)exploration of alpha particle-driven instabilities in a power-plant-relevant range oftemperatures, and (d) temperature control and removal of helium ash andimpurities with strong exhaust pumping. Technology scopes would include (a)integration of steady-state power plant relevant fusion technology: large-scale
high-field superconducting magnets; long-pulse high-heat-load plasma-facing
components; control systems; heating systems, and (b) testing of blanket modules
for breeding tritium.

III.C Performance Projections
Based on an extensive experimental database, the Study applied the present
understanding of tokamak physics to predict the ranges of performance of the three
approaches. It concluded that there is confidence that ITER and FIRE will achieve theneeded burning plasma performance in H-mode operation and that IGNITOR would
achieve similar performance if it obtains enhancement of confinement by either achieving
H-mode operation or by confinement improvement in tokamak L-mode operation.
However, the likelihood of achieving these enhancements remains an unresolved issue
between the assessors and the IGNITOR team.
Present uncertainties in transport models lead to some variations in the projected
performance, particularly the fusion power gain. The Study also identified otheroutstanding scientific and technical issues relating to each of the three options. Most ofthese can be addressed through continuing research and development, including modeling11and experiments on existing devices, in parallel with construction of a burning plasma
experiment.
III.D Schedules and Costs
Construction schedules were reported as 5 years for IGNITOR, 6 years for FIRE,
and 9 years for ITER. FIRE is not at the same level of readiness as ITER and IGNITOR
and will require some additional time to be ready for construction. ITER must complete
international negotiations and agreement before construction can commence.
Cost information was obtained from the ITER and FIRE teams and was assessed
within the limited resources available. All costs were converted to 2002-US dollars. ITER
assumes an international cost-sharing approach while FIRE costs are estimated as a US
project.
•

As an Italian project, IGNITOR has been designed in detail with supporting R&D.
It has a detailed cost estimate that is confidential for business purposes and was
not made available.

•

The estimate for FIRE is about $1.2 B including about a 25% contingency. It isbased on an advanced pre-conceptual design using in-house and some vendor
estimates.

•

The purpose of the ITER cost information is to provide accurate estimates of therelative “value” of all the tasks necessary for construction to facilitate
international negotiations on task sharing. The cost information is based on alarge engineering effort (about 1000 PPY) and a large R&D effort (about $900M)
with prototypes of all key components. Also, the ITER cost information (about 85
procurement packages) is based on input from industries in all the present parties.
The Study reports that the estimate of the ITER total “value,” when converted to2002 US dollars, is about $5 billion. The actual cost estimate is to be developedby each party using its own procedures, including the use of contingency. Thus,
the ITER cost information does not included explicit contingency. In therecommended strategy (Section IV) the Panel estimates that the desired role for
US participation in ITER will likely require additional funding of approximately$100M/yr. This cost is estimated for that of a non-host partner, for which the total
cost to construction is anticipated to be approximately 20% of the ITER total
value of $5B. If the cost is spread over ten years, the annual estimated cost is$100M.

The Study’s engineering assessment concluded that there are no outstanding
engineering-feasibility issues to prevent the successful design and fabrication of any of
the three options. However, the three options are at very different stages of engineeringdevelopment.
•

ITER and IGNITOR have well-developed engineering designs:•

IGNITOR has carried out R&D and built full-size prototypes for essentially all
major components.

•

ITER has been supported by a comprehensive R&D program. Also, ITER has
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demonstrated full-scale prototypes for essentially all major components of thefusion core and their maintenance.
•

FIRE is at the advanced pre-conceptual design level. It has benefited from the
R&D for CIT and BPX (previously proposed high magnetic field burning plasma
projects), from the R&D that has supported the high magnetic field IGNITOR
project, and most recently from the R&D of the ITER project.

III.E Paths for Future Development
Finally, we restate a portion of the Study conclusions on the roles of the three
approaches within the development paths for fusion energy.
•

IGNITOR allows early demonstration of an important fusion milestone, burning
plasmas with a low initial facility investment cost. Because of its short pulse
length, IGNITOR cannot thoroughly investigate burn control and/or advanced
tokamak modes. IGNITOR could be an element of a portfolio of experiments
supporting ITER-based or FIRE-based development scenarios.

•

A FIRE-based development plan reduces initial facility investment costs andallows optimization of experiments for separable missions. This option aims at
smaller extrapolations in physics and technology. Assuming a successful
outcome, a FIRE-based development path provides for additional optimization
before further integration steps are needed, allowing a more advanced and/or lesscostly integration step that will follow.

•

An international tokamak research program centered around ITER, which
includes other performance-extension devices throughout the world, has thehighest chance of success in exploring burning plasma physics in steady-state.
ITER will provide valuable data on integration of power-plant relevant plasma
support technologies. Assuming a successful outcome (demonstration of highperformance AT burning plasma), an ITER-based development path would leadto the shortest development time to a demonstration power plant.

See Appendix B for the development path considerations of the Panel.

IV. THE RECOMMENDED STRATEGYThis section recommends a strategy to establish a U.S. burning plasma program.
The scientific challenge of a burning plasma program, and its crucial role in thedevelopment of fusion energy, was discussed in Section I. An extensive and in-depth
process carried out by the fusion energy science community has evaluated the detailed
technical foundation for the strategy, as described in Section II. The powerful scientificopportunities offered by the three options for a burning plasma experiment are delineatedin Section III. These three sections together establish the framework for ourrecommended strategy.

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IV.A Basis for the Strategy
The recommended strategy follows from the following set of findings that derivefrom a scientific analysis of the experimental options and of the overall fusion energy
development needs.
A burning plasma program is needed as a crucial scientific element in thedevelopment of fusion energy. The U.S. and world fusion programs are now
technically ready to proceed with the construction of a burning plasma
experimental facility.
The frontier science introduced by burning plasmas, the physics and technologicalchallenge of creating this plasma state in the laboratory, and the importance of
demonstrating the achievement of fusion power have long been appreciated. There is
now essential unanimity in the fusion science community that we have the scientific andtechnological capability to accomplish these major steps.
A burning plasma experiment would be an integral part of the fusion energy
sciences research program. Underpinning this program is a strong core science andtechnology element that will greatly benefit from, and contribute to, the burning
plasma experiment.
The burning plasma effort was called for in the science-based fusion energy
program restructured in 1996 and has been a missing element in our fusion energy
sciences program. In addition to burning plasma science, the development path to fusion
power requires fundamental understanding of the underlying science and technology,
optimization of the magnetic configuration, investigation of steady-state plasmas, and thedevelopment of low-activation materials and fusion technology. A core science andtechnology program focuses on fundamental understanding, confinement configuration
optimization, and the development of plasma and fusion technologies. These topics areadvanced in the core program through experimental, theoretical, and computational
activities. This core program is essential to the successful and full exploitation of aburning plasma program. The guidance of the burning plasma program rests on theknowledge and the scientific work force generated by the core program. The current
level of effort within the core program, following the major budget reduction in 1996, isinsufficient to meet these challenges.
The ITER facility is proposed as an international project at power-plant scale with acomprehensive science and technology program. It has a well-developed engineering
design, and negotiations for construction are underway. U.S. participation in ITER
would have substantial domestic benefits.
ITER offers the opportunity to investigate the strongly coupled, nonlinear physics
phenomena that dominate self-heated plasmas, in near steady-state conditions at the sizeand scale expected for a power source. It has been designed by an international team,drawing on scientific and engineering talent from around the world. An extensive arrayof experimental tools will be available to control the plasmas and uncover the underlying
science. Operation of the long pulse burning plasma will also advance our capabilities ina wide array of technologies needed for fusion energy development. The operation andstudy of a power-plant scale facility that integrates burning plasmas, near steady-state,
14

and key fusion technologies would constitute a huge step toward commercial fusion
power.
The FIRE facility is proposed as a smaller scale, U.S.-based project with a broad
science program. It has an advanced pre-conceptual design. Conceptual andengineering designs are needed prior to construction. International participation in
FIRE would provide substantial benefits.
FIRE offers the opportunity to investigate the strongly coupled physics
phenomena that dominate self-heated plasmas, under quasi-stationary conditions. It has
been designed by the U.S. Significant experimental tools will be available to control theplasmas and uncover the underlying science. Operation of a burning plasma in FIRE
would advance specific plasma technologies relevant to fusion energy development. The
burning plasma science learned would constitute a large step forward in fusion energy
development.
IGNITOR has a well-developed design and is moving forward in Italy. Its operation
would provide valuable insight into burning plasma science, although it is notdesigned to be the sole burning plasma facility in the world.
IGNITOR offers the opportunity for an early study of the strongly coupledphysics phenomena that dominate self-heated plasmas. It is aimed at an early
investigation of burning plasmas, and is enabled by a smaller size and less extensive
technical capability.
ITER and FIRE are each attractive options for the study of burning plasma science.
Each could serve as the primary burning plasma facility, although they lead todifferent fusion energy development paths.
Both ITER and FIRE would uncover critical new science in, and generate a large
leap in our understanding of burning plasmas, although there are differences inexperimental capabilities. Viable and aggressive development paths have beenformulated in which either ITER or FIRE form the primary and first burning plasma
experiment. In either case, additional key elements are needed, although there aredifferences between the case in which integration of burning plasma physics, long pulse,
and technology occurs earlier (ITER) and that in which it occurs later (FIRE). Bothcould contribute to, and benefit from, an interaction with the core science program, whichaims to develop predictive capability and to extend the results to other magnetic
configurations and new experiments.
Because additional steps are needed for the approval of construction of ITER or
FIRE, a strategy that allows for the possibility of either burning plasma option isappropriate.

IV.B Major Recommendations
Since ITER is at an advanced stage, has the most comprehensive science andtechnology program, and is supported internationally, we should now seek to join
15the ITER negotiations with the aim of becoming a partner in the undertaking, withtechnical, programmatic and timing considerations as follows:
The desired role is that the U.S. participate as a partner in the full range ofactivities, including full participation in the governance of the project and theprogram. We anticipate that this level of effort will likely require additional
funding of approximately $100M/yr.
The minimum acceptable role for the U.S. is at a level of effort that would allow
the U.S. to propose and implement science experiments, to make contributions
to the activities during the construction phase of the device, and to have accessto experimental and engineering data equal to that of all partners.
The U.S. performs a cost analysis of U.S. participation and reviews the overall
cost of the ITER project.
The Department of Energy concludes, by July, 2004, that ITER is highly likely
to proceed to construction with terms acceptable to the U.S. Demonstrations oflikelihood could include submission to the partner governments of anagreement on cost-sharing, selection of the site, and a plan for the ITER Legal
Entity.
Since FIRE is at an advanced pre-conceptual design stage, and offers a broad
scientific program, we should proceed to a physics validation review, as planned,
and be prepared to initiate a conceptual design by the time of the U.S. decision on
participation in ITER construction.
If ITER negotiations succeed and the project moves forward under terms
acceptable to the U.S., then the U.S. should participate. The FIRE activity should
then be terminated.
If ITER does not move forward, then FIRE should be advanced as a U.S.-based
burning plasma experiment with strong encouragement of international
participation.
If IGNITOR is constructed in Italy, then the U.S. should collaborate in the program
by research participation and contributions of related equipment, as it does withother major international facilities.
A strong core science and technology program is essential to the success of theburning plasma effort, as well as the overall development of fusion energy. Hence,
this core program should be increased in parallel with the burning plasma science
initiative.
A burning plasma science program should be initiated by the OFES with additional
funding in FY 04 sufficient to support this strategy.
16

V.

PRIORITIZED OBJECTIVES FOR U.S. PARTICIPATION IN ITER

Achievement of the U.S. burning plasma goals requires that the implementationof the recommended strategy be guided by clear prioritized objectives, as detailed inAppendix C. U.S. negotiations regarding the ITER construction project and research
program should assure that the U.S. participants will be able to achieve the highest
priority objectives.
In prioritized order, U.S. objectives for U.S. participation in ITER are:(1)
to perform research on burning plasmas in the tokamak configuration, tocontribute to the science base for the full range of toroidal confinement
configurations;(2)
to develop enabling technology that supports the burning plasma research andpositions the U.S. to more effectively pursue burning plasma research;(3)
to advance fusion energy technologies, to contribute to the technology basenecessary for a demonstration fusion power plant; and(4)
to increase involvement of U.S. industry in the fusion program, both in design andfabrication of components for burning plasma experiments and in preparation for
U.S. design and construction of a demonstration fusion power plant.
Achievement of the highest priority U.S. objectives requires that negotiated terms
assure the following minimum roles and opportunities:(a)a significant U.S. role in the decision-making regarding the ITER research
program, including overall research directions and selection of experiments;(b)opportunities for U.S. researchers from all segments of the U.S. fusion
community (universities, laboratories, and industry) to propose, plan, conduct andparticipate in experiments as members of the ITER research team;(c)opportunities for U.S. researchers to play leadership roles and participate in
ITER’s topical task forces, with access to all data from all available systems for
all ITER experiments;(d)opportunities to apply theory and integrated modeling in design and analysis ofexperiments and in benchmarking of models against ITER data;(e)opportunities for the U.S. to develop and contribute equipment during theconstruction and operations phases of the device, and to have access toengineering data equal to that of all partners;(f)opportunities to propose/develop/design/fabricate/install/operate advanced
diagnostics and enabling technology (e.g., plasma control tools) beyond thebaseline;(g)opportunities to participate in fusion energy technology activities such as thedevelopment and testing of blanket modules.

17

References
1.An Assessment of the Department of Energy’s Office of Fusion Energy Sciences
Program, National Research Council, National Academy Press, 2001.
2. Realizing the Promise of Fusion Energy, Secretary of Energy Advisory Board Task
Force on Fusion Energy, U.S. Department of Energy, August, 1999.
3. Review of Burning Plasma Physics, Fusion Energy Sciences Advisory Committee,
Department of Energy, DOE/SC-0041, September, 2001.
4. 2002 Fusion Summer Study, report under preparation, http://web.gat.com/snowmass/.

18

APPENDICES

19

A. FUSION PROGRAM INTEGRATIONThe Fusion Energy Sciences Program is developing the science and technology
needed for an economically and environmentally attractive fusion power source. This
includes three mission elements: the advancement of plasma science, the development offusion science, technology and plasma confinement innovations through a portfolio
approach, and the pursuit of burning plasma physics and fusion energy development as apartner in the international effort. As described earlier, this panel report recommends a
strategy for initiating the crucial and now missing program element: the study of burning
plasmas in the development of practical fusion energy. This Appendix describes theintegration of this new burning plasma program into the overall Fusion Energy Sciences
Program and into broader scientific, educational, and industrial contexts.
A.1 The Role of a Strong Program in Core Fusion Science and Technology
Recommendation 6 from the Snowmass Executive Summary states an essential
feature of fusion program integration:
A strong base science and technology program is needed to advance essential fusion
science and technology and to participate effectively in, and to benefit from, theburning plasma effort. In particular, the development path for innovative
confinement configurations would benefit from research on a tokamak-based
burning plasma experiment.
We strongly endorse this recommendation. The base, or core, program develops
underlying fusion science and technology and provides the knowledge base to optimize
the magnetic configuration for plasma confinement. Thus, while the tokamak is presently
in the most advanced stage of development and is presently the only configuration withthe requisite data base required for extrapolation to the burning plasma regime, otherconfigurations may be more desirable for ultimate deployment as power sources. It istherefore of critical importance that the exploration of these alternative magnetic
configurations move forward expeditiously so that the understanding of their confinement
properties reaches maturity prior to future decisions on the construction of a fusion
demonstration facility. The burning plasma experiment based on the tokamak
configuration will enhance this effort by providing generic scientific results andtechnologies, which can be incorporated into the knowledge base of these alternative
approaches.
The core program is also essential to the successful and full exploitation of theburning plasma program. Predictions on the confinement, stability properties anddynamics of plasmas in the burning regime have all come from the intense experimental,
modeling and theoretical efforts of the core program. The underpinnings of any burning
plasma experiment therefore fundamentally rests on the foundation of knowledge that hascome from the core program. Moving forward with a burning plasma experiment requires
experimental scientists, engineers, and theorists and computational scientists from thiscore to design experiments and interpret the results.
20

A.2 Burning Plasma Studies Within the Overall Fusion Energy Sciences Program
The creation and control of a magnetically confined burning plasma is a scientificand technological grand challenge. Essential science and technology that is still being
developed by the core fusion research programs of the world include understanding
energy confinement and its scaling with system size, geometry, and magnetic
configuration; demonstrating plasma heating techniques in the form of high energy
neutral beams and radio frequency waves; and developing innovative technologies tohandle the high heat flux at the edge of a burning plasma. The body of knowledge
developed thus far has created confidence in designs for burning plasma experiments.
The flexibility built into these designs will accommodate the inevitable uncertainties andchallenges associated with a major research and development step.
Scientific flexibility, excellent diagnostics, and close coupling to theory andsimulation are critical features of an integrated research program in burning plasma
physics and technology. The understanding gained through the study of burning plasmas,
when coupled with parallel advances in theory and simulation, will lead to more rapid
progress towards the ultimate goal of an optimized fusion reactor concept. Moreover,because of the common principles underlying the physics of toroidal magnetic
configurations, the time to implement and evaluate other promising approaches tomagnetic confinement of high-temperature plasma may be reduced as a result of an
integrated burning plasma development path.
While tremendous progress has been made, further developments are needed to
exploit fully the benefits of the burning plasma program. Research on existing facilities
enables improved predictions of the phenomena to be explored in burning plasma
experiments, readies scientific instruments for fusion’s neutron environment, andaddresses remaining technology issues. The physics basis for a tokamak burning plasma
experiment will benefit from further understanding of such critical issues as the structureof the edge pedestal, the H-mode transition threshold, and the dynamics and stabilization
techniques for “neoclassical tearing modes.” Technology research and development will
improve plasma-facing materials for walls and divertor plates and address tritium
retention issues. The ongoing exploration of these and other issues will play a critical rolein ensuring the success of a burning plasma experiment in terms of science andtechnology output.
A.3 Strengthening the Core Science and Technology Program
To fully realize the investment in a burning plasma effort and to move towards thepractical use of fusion energy, the core science and technology program should be
strengthened. Examples of the strengthened core program that directly benefit the burning
plasma program include novel diagnostic development and deployment, increased theory
and computational efforts, optimized utilization of existing experimental facilities andenhanced technology development. Success in reaching our nation’s fusion energy goals
will require expansion of the infrastructure of skilled and expert persons working on
fusion. A strengthened core program will help meet this need, especially by training
young scientific and engineering talents who share the vision of virtually unlimited
energy for mankind and the intense curiosity over the underlying science.
21

Many of the benefits derived from a strengthened core program can be realized in
the near term and applied during the early stages of a burning plasma program. Existing
experimental facilities can develop and test the new instrumentation and plasma control
capabilities needed to characterize and manipulate the high-temperature plasma dynamics
in the burning plasma experiment. This in turn, when combined with the enhanced
theory/computational effort and the increased facility utilization, would allow for (i) the
development of more realistic and better validated models of burning plasma discharges
and (ii) the development of improved plasma control strategies. Similar advances are
expected from developments in technology. Strengthening of all of these activities
increases the likelihood of discoveries that can be incorporated into a burning plasma
experiment to enhance its performance.
A.4

The Impact of Burning Plasma Studies on Science and Technology Beyond
FusionResearch in a well-diagnosed and flexible burning plasma experiment will have
impacts beyond the sphere of fusion science. Plasma pressure profile dynamics in thepresence of intense alpha particle heating is a central component of burning plasma
science. The associated study and controlled manipulations in the laboratory of matter
under these extreme conditions will provide new challenges and insights and contributeto the broad scientific knowledge base of humanity. A deeper understanding of nonlinear
dynamics and non-equilibrium statistical mechanics and transport will extend beyond
fusion, as these disciplines are important to a diverse range of phenomena including fluid
dynamics, chemical systems, biology, hydrology, geophysics, space physics, engineeringand systems design. Turbulence studies in burning plasma will provide insights to studiesof neutral fluid turbulence. Studies of magnetic reconnection, important for astrophysicalsystems, will be extended in a burning plasma program because of the increased
separation of scales compared to present experiments, as well as the presence of energetic
particles. The demanding constraints on the support technologies and instrumentation
imposed by the high temperature, energy flux, and radiation of a burning plasma will bebased on and stimulate technological advances in advanced technologies including
robotics, materials, and remote information and data management. A burning plasma
program will also contribute broadly to many of the nation's larger technology interests,
including systems control, materials science, superconducting technology, and remotematerials handling and systems maintenance. Finally, developing a predictive capabilityof burning plasmas that can contribute to the development of other fusion concepts will
promote broad advances in diagnostics and computing.
A.5 The Burning Plasma Program Interaction with Industry and the International
Community
The successful implementation of a burning plasma program will depend on the
integrated efforts of creative scientists presently working at universities and national
laboratories with those of their counterparts in high-technology industries. A burning
plasma experiment will attract increased industrial participation in fusion research,
thereby leading to innovations that will contribute to our nation’s broad science andtechnology infrastructure.
22

Fusion research has benefited immensely from international collaborationworldwide. The ability to independently reproduce experimental observations, to conduct
non-dimensional studies over several experiments, and to have access to an extensive
fusion database is crucial for advancing the understanding of fusion science andtechnology. In planning for a burning plasma experiment, the U.S. core program should
maintain a strong international collaboration by taking advantage of complementary
experimental facilities outside of the U.S., including new facilities on the horizon, toaddress key scientific issues relevant to the success of the burning plasma experiment.

23

B. FUSION DEVELOPMENT PATHS AND THE BURNING PLASMAEXPERIMENT
B.1 The Elements in the Fusion Development Path
A burning plasma experiment is a crucial and now missing step on a path todevelop fusion as a practical source of energy. This goal is embodied in realizing ademonstration power plant (DEMO). A DEMO will employ all the physics andtechnologies needed in a commercial power plant at a scale readily extrapolated tocommercial units, will put net electric power on the grid with reasonable availability, andwill provide a licensing, cost, and public acceptance basis for commercial units.
A development path must include four major scientific elements (Snowmass
Major Conclusion #5):
1.
2.
3.
4.

fundamental understanding of the underlying science and technology, andoptimization of magnetic configurations,plasma physics research in a burning plasma experiment,high performance, steady-state operation,
development of low activation materials and fusion technologies.

1. Fundamental Understanding and Configuration Optimization
Snowmass Major Conclusion #6: A strong science and technology program is neededto advance essential fusion science and technology and to participate effectively inand to benefit from the burning plasma effort. In particular, the development pathfor innovative confinement configurations would benefit from research on a
tokamak-based burning plasma experiment.
The Fusion Energy Sciences Program is providing basic plasma confinement
physics knowledge from experimental, theoretical, and computational studies on a
portfolio of magnetic configurations, plasma support technology research, and fusion
technology research. Dramatic advances have been made in the last decade in theunderstanding of the physics of high-temperature plasmas confined by magnetic fields,
both through more sophisticated plasma diagnostic measurements and through the greatly
enhanced computational power now available to researchers. These efforts are criticalbecause the innovations required for practical fusion energy can only arise fromcontinued development of accurate physical understanding. Ultimately, the most
attractive and competitive fusion power source is most likely to arise from efforts to more
fully understand and control plasma behavior. Furthermore the scientific progress
represented by this work has its own fundamental value.
Strong support for the fundamental understanding of the underlying science andtechnology for fusion energy will be essential throughout the time of development offusion.
The burning plasma experiment, in order to play its crucial role in advancing
fundamental understanding, must have the flexibility to study a broad range of scientificissues. Its measurement systems must be sophisticated enough to understand the plasma

24behavior and it must provide sufficient experimental time to allow thorough parameterscans and systematic studies.
Configuration optimization includes both the development of advanced tokamak(AT) operating modes and also studies of alternative configurations of the fusion plasma.
While the designs of the three candidate burning plasma proposals are based onconventional tokamak physics already in hand, current tokamak research is now focusedon the AT line, seeking to define the ultimate potential of the tokamak as a magnetic
confinement system, with special emphasis on developing the physics of steady-state
operation. In the decade until a burning plasma can begin operation, an advanced physics
basis should become available and it can be expected that pursuit of advanced physics
scenarios will become a major research focus in the burning plasma experiment.
Superconducting non-burning tokamak facilities under construction abroad are designed
to take this research into the steady-state regime in the next decade.
The Program must also support the advance of other confinement configurations,as candidates for fusion energy development. Study of these configurations also
contributes to the fundamental understanding of plasma physics. In the U.S. there are
active programs studying the Spherical Torus (the low aspect ratio limit of the tokamak),the Reversed Field Pinch (with very low external magnetic fields) and the Compact
Stellarator (in which toroidal asymmetry is exploited for stability and steady-state
operation). Smaller programs are underway investigating other innovative plasma
confinement configurations. These programs are all aimed at providing an attractive
confinement configuration for a DEMO or a future reactor.
2. The Burning Plasma Step
Snowmass Major Conclusion #1: The study of burning plasmas, in which self-heatingfrom fusion reactions dominates plasma behavior, is at the frontier of magnetic
fusion energy science. The next major step in magnetic fusion research should be aburning plasma program, which is essential to the science focus and energy goal of
fusion research.
In the next generation of fusion research devices, an experiment is needed that canburn plasma, achieving fusion power gain of at least 5 in order to allow study of plasmas
dominantly heated by the alpha particles produced in the fusion reaction. At a minimum,
proposed burning plasma devices should have a high confidence of reaching this regime
and being able to implement a full and rich experimental program studying such plasmas.
Additional benefits would be provided by a burning plasma experiment that could be
extended to longer pulse lengths and advanced tokamak research and to employ anddemonstrate plasma and fusion nuclear technologies.
3. High Performance, Steady-state
It is desirable, although not essential, that a fusion power plant be able to operate
in steady-state. A significant component of a world fusion development program should
therefore focus on the plasma physics and technology issues of steady-state. Such
research can be done in non-burning plasmas, but it would be very advantageous to beable to do it in a burning plasma. In the next generation of major national fusion
experiments, a significant set of superconducting coil, long pulse, non-burning fusion25

devices appears available to carry forward this research line. Tore-Supra in Europe is anoperating long pulse tokamak with a superconducting toroidal coil and LHD in Japan is
an operating superconducting stellarator. Superconducting tokamaks under construction
are the KSTAR in Korea, the HT-7U in China, and the SST in India. The proposed
superconducting tokamak JT-60SC in Japan would be an important element of thisresearch. The W-7X stellarator in Germany (under construction) will also make important
contributions to long pulse issues.
4. Low Activation Materials and Fusion Technologies
Fusion energy technologies provide for plasma control; plasma fueling, heating,and current drive; magnets for plasma confinement; steady-state operation; safe handlingand breeding of tritium; capture of fusion neutrons; and extraction of process heat and its
eventual conversion into electricity. These technologies must be integrated to result inhigh reliability, availability, and maintainability in a practical, energy producing systemwith low residual radioactivity. Substantial development of the blankets that surroundthe plasma to capture the neutrons is necessary. Many options exist for choice of coolant,
breeding material, structural material, blanket mechanical configuration, and operating
parameters. The development of the knowledge base for use of low activation materials
is particularly crucial. New facilities and dedicated test stands will be needed. A highfluence intense neutron source is needed to obtain lifetime irradiations of candidate
fusion materials to develop irradiated materials property data. A high fluence volume
neutron source is also needed to allow irradiation and operational development of full
fusion nuclear technology components.

B.2 Role of candidate burning plasma experiments in fusion development
paths
Set against the background of the above general development path requirements
and relying on the report of the development path group from the recent Snowmass
meeting, we offer the following evaluations of development paths. These paths assume
that the US participates in the construction of only one of the proposed burning plasma
experiments and that its program is successfully carried out.
ITER
A fusion development path with ITER as the burning plasma element would leadto the shortest development time to a demonstration power plant. The ITER device lieson the most direct path presently foreseen to fusion energy, through a superconducting
coil toroidal experimental test facility (ETF) integrating physics and technology at power
plant scale. ITER will provide a fully acceptable burning plasma experiment in terms ofoperational regimes and plasma measurement capabilities. Its operational flexibility andlong pulse capability (about one hour) will provide an excellent laboratory for advanced
tokamak physics development. The advanced physics basis that can be achieved in ITER
will allow an advanced physics DEMO to follow ITER (Fig. 1). ITER will make a major
contribution to the physics and technology of steady-state. It has a duty factor goal of
20% and its contribution, taken with the contributions of the other superconducting coilfacilities listed above, will provide a firm basis for a steady-state DEMO. ITER will also
26

provide significant initial tests of fusion nuclear technologies. On ITER, tritium handlingexperience can be gained and a modest number of fusion blankets can be shown to breed
tritium and extract heat. ITER will enable fusion to demonstrate safety and licensing
abilities at power plant scale.
Additional necessary facilities in this development path include an intense neutron
source for irradiated materials data and a component test facility for high fluence blanket
testing and development.
The development path in Fig. 1 indicates that the best confinement configuration
will be selected for DEMO, taking into account results from ITER and the otherdevelopment path elements, from the configuration optimization experiments, and fromthe anticipated advances in our computational ability to simulate integrated fusion
systems. It is also possible that a tokamak DEMO might proceed in parallel with a large
scale integration step (Experimental Test Facility ETF/DEMO) based on anotherconfiguration. Multiple national DEMOs might employ different configurations.
The ITER path requires an international agreement to be concluded to build
ITER, bringing with it the advantages of cost sharing and program stability from theconclusion of such an agreement but the disadvantages of the complexity of realizing
such an agreement and the complexity of an international project management system.
FIRE
FIRE would support a successful development path to fusion power. The FIRE
development path seeks to address the burning plasma issues and advanced tokamak
issues at the earliest time and the smallest necessary device scale. The FIRE device uses
the cryogenic copper coil high magnetic field approach to obtaining high fusion gain in amuch smaller, substantially less costly device. In this development path, FIRE's
operational regimes and measurement capabilities will provide the basic burning plasma
physics. FIRE has set ambitious goals in advanced tokamak physics. FIRE can provide asignificant exploration of advanced tokamak physics, since its pulse length can be 1-3
current diffusion times in the plasma. FIRE's modest requirements in tritium handlingand low neutron fluences do not require engaging power plant level safety and licensing
issues.
The development path based on FIRE spreads the various development path needs
over a number of facilities internationally (Fig. 2). While the ITER and FIRE
development paths (Figs. 1 and 2) share all other development path items, the FIRE path
places greater emphasis on some of these elements. The long pulse/steady-state researchelement will be done on the superconducting facilities listed above. The advanced
tokamak physics basis will be obtained from FIRE, ongoing experiments, and thesuperconducting facilities. While the FIRE experiment would contribute to important
plasma technology development like high heat flux plasma facing components andhelium ash pumping, the FIRE development path places much more reliance on the set of
fusion nuclear technology facilities discussed above. The component test facility willplay a greater role in providing the fusion technology experience for the DEMO.
The FIRE development path approach will require a physics and technology
integration step (Advanced ETF in Fig. 2) to follow FIRE and the associateddevelopment path elements. With the benefit of the completion of research on FIRE andthe other research elements, the integration step following FIRE would be more advanced27

in physics and technical reach than ITER. The DEMO to follow this integration stepwould profit from this advanced technical basis. However, the deferral of the integration
step may add time to the development path. It has been suggested, as indicated in the
figure, that the Advanced ETF and the DEMO could be sequential devices or an upgradeof one device into the next within a single facility, perhaps reducing the additional time toabout one-half of one machine generation.
At the decision point in Fig. 2, if the FIRE development path is successful, it isenvisioned that a tokamak ETF followed by a DEMO would be built. An ETF/DEMO
based on an alternate concept might also be done in parallel with or as an alternative tothe tokamak ETF/DEMO.
The FIRE path envisions an internationally coordinated program with
development path needs spread over major nationally run facilities, streamlining themanagement approach. However, the international community is concentrating at thepresent time on concluding the agreement to proceed with ITER.

IGNITORIGNITOR could be an element of a portfolio of experiments supporting ITERbased or FIRE-based development scenarios. The high field copper magnet IGNITOR
device has a well developed design focused on the technical objective of providing an
early pulsed burning plasma demonstration and exploration of the subsequent burndynamics for about one current diffusion time at the lowest device cost. While
IGNITOR's pulse length does not allow a thorough exploration of burn control oradvanced tokamak modes, IGNITOR presents credible advanced performance scenarios
to produce internal transport barriers on a transient basis.

28

29

C. POTENTIAL US ROLES AND INTERNATIONAL ASPECTS OF BURNING
PLASMA
C.1

Background Information

This appendix identifies potential U.S. roles in selected options for burning
plasma experiments (BPX). For each potential role, the report addresses topics such as
the technical scope and relevance to U.S. capabilities and interests. No particular level ofoverall funding for participation in a BPX is assumed. Rather, this appendix provides amenu of roles to consider.
All three approaches within the U.S. burning plasma program include international
aspects: U.S. participation in ITER, non-U.S. participation in FIRE, and U.S.
participation in an Italian IGNITOR. For the purpose of guiding the negotiation of theinternational aspects of the U.S. burning plasma program, this appendix also addresses
U.S. objectives for participation in the burning plasma program, forms of and priorities
for international contributions to the three burning plasma approaches, and other aspects
as relevant to the approach.
C. 2

Overall Guidelines and Principles for Assessing Potential Roles

The planning and preparation of any BPX initiative must engage a broad segment of
the U.S. fusion scientific community to assure significant benefits to both the intellectual
development of fusion science in the U.S. and the success of the burning plasma project.
U.S. responsibilities and resources would fall into two rather broad areas: those needed toconstruct and equip the facility and those needed to operate and exploit it scientifically.
Benefits derived directly from the former would occur in the nearer term and be more
technological in character, although much scientific experience would be gained from theactivities required for preparing for operation. Those from the latter would occur in thelonger term and be more scientific, although much valuable technological experiencewould be gained from operation and maintenance of a burning plasma experiment.
Among the BPX options currently under consideration -- building FIRE domestically butwith some international participation, participating in ITER internationally or supporting
IGNITOR in Italy1 -- the relative share and balance of these two areas of activities borneby the U.S. would vary considerably. In a domestic construction project, the U.S.
responsibilities would include nearly the full scope of design, fabrication, installation,
testing, and operation. In any shared international endeavor, the responsibilities assumed
by the U.S. would span design, construction, operation of equipment and exploitation of
the facility, so as to assure maximum continuity and experience-in-depth. The U.S. would
not be responsible for the full project. Nonetheless, whatever the final BPX option
chosen, it must be anticipated that both types of activities will be undertaken.
Within the area of construction activities, several criteria for U.S. participation can bereadily identified:•1

building on U.S. experience, strength, and/or leadership;

IGNITOR proponents have also suggested the possibility of constructing an Ignitor-like device in the US.

30

•
•
•

maintaining/increasing the breadth and depth of U.S. capability in fusion related
technologies; andincreasing U.S. industrial capacity in high-tech areas, especially ones important tofusion.
confidence to complete task(s) within the allocated U.S. budget.

Certainly, anything undertaken should support the success of the overall project. If the
project is international, similar criteria will likely be adopted by the other parties; inwhich case, the U.S. can assume that, in part, it will also be accepting some
responsibilities that do not necessarily rank high as measured by these criteria but arenonetheless important to the project. For a domestic project, as noted earlier, the U.S.
would naturally be responsible for all aspects.
Criteria for programmatic or operational activities include:
•
•
•
•
•

providing opportunity to study burning plasma science under reactor-relevant
conditions;advancing fusion science or technology in areas important to the U.S.;
providing scientific experience relevant to other magnetic configurations;building on U.S. scientific strengths and providing synergy/continuity withexisting U.S. facilities; andbroadening U.S. expertise by providing opportunities not available on existing
U.S. facilities.

Again, for an international project, other parties would likely have similar criteria. As aconsequence, the U.S. might expect to lead in some areas and support in others, with dataand other information being open to all participants.
C.3

U.S. Candidate Roles in Burning Plasma Experiments

A relatively comprehensive list of candidate roles and tasks for the U.S. is given in
the table at the end of this appendix. These candidate roles/tasks cover a broad range ofpotential activities in terms of plasma physics, engineering and technology, and they
cover potential activities in all phases of a burning plasma experiment. A brief task
description is provided and then each potential task is characterized in several ways.
First, possible contributions to the U.S. plasma science program are identified andthey are rated low, moderate or high. A “high” rating means that the task will make avery substantial contribution to the further development of plasma science and related
progress towards fusion energy science. Similarly, contributions to U.S. fusion
technology are identified and rated in the same manner. A “high” rating here means
substantial contributions to the technology required for fusion energy. Finally, theexisting US capability to perform the task is rated as high, moderate or low with somebrief comments.
Lastly, possible U.S. roles with respect to the three main burning plasma options(ITER, FIRE, and IGNITOR) are described. These roles are only suggestive at this time
and would be subject to much further discussion with the project leadership of each
option.
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C.4

Overall Objectives for U.S. Participation in the Burning Plasma Program:
In prioritized order, U.S. contributions to the Burning Plasma Program should
address the following U.S. objectives:(O1) to perform research on burning plasmas in the tokamak configuration, tocontribute to the science base for the full range of toroidal confinement
configurations,(O2) to develop enabling technology that supports the burning plasma research andpositions the US to more effectively pursue burning plasma research,(O3) to advance fusion energy technologies, to prepare the technology base necessary
for a demonstration fusion power plant,(O4) to increase involvement of U.S. industry in the fusion program, both in design andfabrication of components for burning plasma experiments and in preparation for
U.S. design and construction of a demonstration fusion power plant.
C.4.1 U.S. Participation in ITER Activities
Development of the U.S. negotiation plan for U.S. participation in ITER demands
clear objectives, priorities and forms for contributions, and U.S. community “needs” and“desires”, as well as considerations of the functional requirements for the ITER
organizational and management structures.
U.S. ITER Activities should consist of 2 types:(A1) U.S. ITER Project Activities, in which the U.S. addresses scope that is within the
ITER construction project; examples include tokamak components, start-up
diagnostics, superconducting strand, etc.
(A2) U.S. ITER Program Activities, in which the U.S. addresses scope that is outside
the ITER construction project; examples include preparations for physics andtechnology research on ITER, the research/design/fabrication of post-construction
scope such as advanced diagnostics and plasma control systems, and ITER
operations.
Because performance of burning plasma research by U.S. researchers is theprimary objective of U.S. participation in ITER (O1), it is important that the US and
ITER organizational structures and processes enable and enhance opportunities for U.S.
researchers to exploit ITER as a research tool, as a partner in the research activity.
Elements that should be assured in the negotiations include:
(R1)
(R2)

a significant U.S. role in the decision-making regarding the ITER research
program, including overall research directions and selection of experiments;
opportunities for U.S. researchers from all segments of the U.S. fusion
community (universities, laboratories, and industry) to propose, plan, conduct andparticipate in experiments as members of the ITER research team;

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(R3)

(R4)
(R5)

(R6)

(R7)

opportunities for U.S. researchers to play leadership roles and participate in
ITER’s topical task forces, with access to all data from all available systems for
all ITER experiments;
opportunities to apply theory and integrated modeling in design and analysis ofexperiments and in benchmarking of models against ITER data;
opportunities for the U.S. to develop and contribute equipment during theconstruction and operations phases of the device, and to have access toengineering data equal to that of all partners;
opportunities to propose/develop/design/fabricate/install/operate advanced
diagnostics and enabling technology (e.g., plasma control tools) beyond thebaseline;
opportunities to participate in fusion energy technology activities such as thedevelopment and testing of blanket modules.

U.S. Contributions to the ITER Project:
US contributions to ITER must meet both U.S. needs and ITER project needs. For
example, it is unrealistic to plan that the US would be allowed to restrict its contributions
to only those items considered most desirable to the U.S. Instead, U.S. contributions will
likely be required to be balanced, contributing to a range of scopes that span fromresearch-enabling products to conventional scope.
(C1) The highest priority should go to contributions that enable research on burning
plasmas, research on burning plasmas and enabling technology (O1 and O2). This
scope would include areas such as baseline diagnostics, plasma control, remoteresearch tools, etc.
(C2) Second priority should go to fusion technologies (O3), particularly those in which
the U.S. has special experience and interest and where U.S. industry could have asignificant role (O4). This scope would include fusion-relevant products such as
superconducting magnets, plasma-facing components, etc.
(C3) Third priority should go to high-tech non-fusion scope, such as more conventional
technical industrial scope. Included would be power supplies, control and dataacquisition, superconducting strand, etc.
Forms of US Contributions to the ITER Project:
The US should agree with the concept of having the US project contributions be
made in four forms:(F1) participation in the ITER Central Team and in the ITER U.S. Field Team; senior
U.S. individuals would be seconded to the ITER Team and would play leadingroles in the project activities; they would receive their direction from the ITER
management.
(F2) “in-kind contributions”, in which the U.S. commits to provide specificcomponents such as several of the 85 procurement packages. For “in-kind”
contributions, the U.S. would receive credit for the value assigned by the ITER
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Legal Entity (ILE), but would be obligated to provide the product irrespective of
the actual cost to the U.S. To assure completion of scope within the budget, theU.S. would have to include sufficient contingency in the budget estimates for “inkind contributions”.
(F3) “fund contributions”, in which the U.S. controls but makes accessible a fund fromwhich U.S. industry would be paid for ILE-specified and procured scope. For“fund contributions,” the ILE would call for bids on specific work-scopes and the
U.S. ITER Project Office would decide whether the requested work-scope would
be eligible for payment from the US fund. If so, the ILE would issue the request
for bids to U.S. (and other parties’) industry and would evaluate the world’s
industrial bids. If a U.S. industry were selected, then the ILE would contract with
the U.S. industry and the U.S. industry would receive payment from the U.S. fundas contractual milestones are met. (Note: the U.S. and the ILE must structure theprocurements such that the ILE- and contractual-specifications and milestones are
identical and the ILE must grant credit when the U.S. industry delivers productsthat meet the contractual specification.)(F4) “cash contributions,” in which the U.S. provides a small amount of cash to becontrolled by the project for scope and expenses outside the negotiatedprocurement packages. This cash contribution is to provide required flexibility to
the ILE. The cash will either be held in a U.S. fund or provided directly to theILE, as negotiated.
It should be expected that construction scopes that are enabling and fusion
technologies (C1 and C2) would be provided as “in-kind contributions” (F2). High-tech
non-fusion scope (C3) could be provided either as “in-kind contributions” (F2) or as“fund contributions”(F3). Remaining, more conventional scopes (C4) should be provided
as either “in-kind contributions” (F2) or “fund contributions”(F3).
Forms of U.S. Contributions to the ITER Program:
Because the first objective of the U.S. burning plasma program is the performanceof research (O1) and the second objective focuses on enabling that research via
contributions that extend the research capability of the facility (O2), it is expected that the
US would engage in an accompanying ITER program. This accompanying program
would entail several components, among them:(P1) design and preparation of the ITER research infrastructure, including researchdecision-making processes and research tools,(P2) participation in topical teams,(P3) development and preparation of advanced diagnostic systems beyond the basic
diagnostic set,(P4) development and preparation of advanced plasma control tools,(P5) development and prototyping of remote collaboration tools,(P6) supporting research on existing facilities, and(P7) theory, simulation and modeling.
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This accompanying programmatic activity must be integrated with the U.S. domestic
program and must be accessible to and involve all segments of the U.S. fusion
community.
C.4.2 Non-U.S. Participation in FIRE Activities
FIRE would be primarily a U.S. national activity, but would invite non-U.S.
participation.
The
U.S.
would
be
responsibleforthedesign/fabrication/assembly/test/operation of the FIRE facility and would manage the
FIRE research program. Non-U.S. participation would enhance and/or accelerate the
FIRE project and/or program.
FIRE Activities should consist of two types:(A1) FIRE Project Activities would address scope that is within the FIRE construction
scope; virtually the entire FIRE facility and associated support facilities would bewithin the FIRE project.
(A2) FIRE Program Activities would address scope that is outside the FIRE
construction project; examples would include preparations for physics andtechnology research on FIRE, the research/design/fabrication of post-construction
scope such as advanced diagnostics, and FIRE operations.
Non-U.S. Participation in FIRE Project Activities
There would be an opportunity for non-U.S. institutions and companies toparticipate in the design and construction phase of FIRE. There may be unique areas ofexpertise and capability where a non-U.S. party would wish to participate as acollaborator or as a contractor to the FIRE project. The details of participation would be
negotiated on a case by case basis.
Non-U.S. Participation in FIRE Research
Non-U.S. participants in the FIRE would likely focus on burning plasma researchand on enabling technology. Elements would include:(R1) participation by non-U.S. researchers in FIRE’s research activities(R2) opportunities for non-U.S. researchers to lead and participate in FIRE’s topicaltask forces(R3) the right for non-U.S. researchers to propose experiments(R4) non-U.S. researcher participation in experiments with access to all data related tothose experiments(R5) proposal/development/design/fabrication/installation/operation of advanced
diagnostics and enabling technology (e.g., plasma control tools) beyond thebaseline(R6) the opportunity for non-U.S. participants to perform theory and integrated
modeling both in design and analysis of experiments

35

(R7)
(R8)

joint work by non-U.S. participants on supporting experiments on non-FIRE
facilities
non-U.S. participation in fusion technology activities.

Non-U.S. Contributions to FIRE:
Non-U.S. contributions to the FIRE project must meet both non-U.S. needs and
FIRE project and program needs. Non-U.S. contributions to FIRE would be in the formof “in-kind contributions”, in which the non-U.S. party commits to provide specificproducts in exchange for the opportunity for participation in FIRE research.
C.4.3 U.S. participation in an Italian IGNITOR
U.S. participation in an Italian IGNITOR would be much like the traditional U.S.
collaboration on international facilities such as JET, JT6-0U, etc. The U.S. community
would identify key areas of interest and would propose to the DOE/OFES a package thatwould include a balance of research participation and supporting hardware. This package
would be discussed with the Italian host of the IGNITOR facility and might result in aformal proposal to the OFES for funding to participate in IGNITOR in the specified
manner. These perspectives are addressed in this part of the white paper.
Performance of burning plasma research by U.S. researchers would be theprimary objective of U.S. participation in IGNITOR. U.S. and IGNITOR organizational
structures and processes must enable opportunities for the U.S. researchers to exploit
IGNITOR as a research tool, as a participant in the research activity. Elements that must
be assured in the negotiations include:(R1) the right for U.S. researchers to propose experiments(R2) U.S. researcher participation in experiments with access to all data related to
IGNITOR experiments(R3) proposal/development/design/fabrication/installation/operation of advanced
diagnostics and enabling technology (e.g., plasma control tools) both in andbeyond the baseline(R4) the opportunity to perform theory and integrated modeling both in design andanalysis of experiments(R5) U.S. participation in fusion technology activities such as the development andtesting of high-field RF systems
U.S. Contributions to IGNITOR:

U.S. contributions to IGNITOR would be focused in areas such as baseline
and advanced diagnostic systems, RF heating components, the pumping system,and the fueling system. The U.S. contributions would be “in-kind contributions,”
in which the U.S. commits to provide specific components in exchange for accessto IGNITOR for associated research. The U.S. would be obligated to provide theproduct irrespective of the actual cost to the U.S. To assure completion of scope36

within the budget, the U.S. must include sufficient contingency in the budget
estimates for “in-kind contributions.”

37