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Report of the FESAC Panel on

A BURNING PLASMA PROGRAM STRATEGY

TO ADVANCE FUSION ENERGY

Table of Contents

 page

Executive Summary 2

I. The Grand Challenge of Fusion 5

I.A Burning Plasma Science 5

I.B The Development Path to Fusion Energy 6

II. Background 7

III. Experimental Options 9

III.A Mission Statements by Proposers 9

III.B Scope of Projects 10

III.C Performance Projections 11

III.D Schedules and Costs 12

III.E Paths for Future Development 13

IV. The Recommended Strategy 13

IV.A Basis for the Strategy 14

IV.B Major Recommendations 15

V. Prioritized Objectives for U.S. Participation in ITER 17

References 18

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 47
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A BURNING PLASMA PROGRAM STRATEGY

TO ADVANCE FUSION ENERGY

EXECUTIVE SUMMARY

Fusion energy shows great promise to contribute to securing the energy future of

humanity. The risk of conflicts arising from energy shortages and supply cutoffs, as well

as 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 the

physics of complex systems, would be a huge step in establishing the potential of

magnetic 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 the

fusion reactions themselves, as occurs in burning stars. The fusion-generated alpha

particles produce new physical phenomena that are strongly coupled together as a

nonlinear 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 the

development 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, to

embark on this step. The fusion community is prepared to construct a facility that will

allow 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 a

comprehensive 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 for

burning plasma experiments.” A FESAC panel was convened for this purpose. The

recommendations of the Panel are based, in large part, on an extensive scientific
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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. to

proceed with this crucial next step in fusion energy science. The strategy was constructed

with awareness that the burning plasma program is only one major component in a

comprehensive development plan for fusion energy. A strong core science and

technology program focused on fundamental understanding, confinement configuration

optimization, and the development of plasma and fusion technologies is essential to the

realization 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 to

different 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 is

appropriate.

With this background, the Panel puts forth the following major strategy

recommendations.

Since ITER is at an advanced stage, has the most comprehensive science and

technology program, and is supported internationally, we should now seek to join

the ITER negotiations with the aim of becoming a partner in the undertaking, with

technical, programmatic and timing considerations as follows:

The desired role is that the U.S. participates as a partner in the full range of

activities, including full participation in the governance of the project and the

program. 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 access

to 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 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 with

other major international facilities.

A strong core science and technology program is essential to the success of the

burning 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 of

humanity. The risk of conflicts arising from energy shortages and supply cutoffs, as well

as 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 have

yielded 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 of

complex 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 the

growing 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. This

is 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 source

of 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 heat

generated 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. When

these 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 and

slow down, transferring their energy to maintain the high temperature of the plasma.

When fusion alpha heating dominates the plasma dynamics, important new scientific

frontiers will be crossed. To create a burning plasma on Earth and systematically

determine 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, and

contribute 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 the

plasma structure and dynamics can increase the loss of heat and particles from the

plasma, and consequently to a reduction in fusion power. Alternatively, these may lead to

a further increase in temperature and fusion power production. Understanding and

modifying these effects on heat and particle transport, the subject of “burn control,” are

essential elements of power plant development.
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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 around

the 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. This

ratio 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 can

drive 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, and

the influence of escaping alpha particles on energy deposition on the surrounding walls,

burning plasma research will extend regimes of plasma-boundary phenomena well

beyond previous experience.

Each of these phenomena individually is at the forefront of high temperature

plasma 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 the

forefront 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 practical

fusion 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 advance

the development of technologies and the engineering database for follow-on devices

needed for commercial power production. Plasma facing components will be pressed to

previously 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 next

level 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 and

environmentally 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 activation

materials 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-understood

and 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 the

high quality of the scientific research in fusion and particularly emphasized the

critical importance of science in attaining the goal of practical fusion power.1

• Optimization of the magnetic confinement configuration: Because the configuration

of the magnetic field confining the fusion plasma has important implications for the

practical realization of fusion power, configuration optimization must be pursued in

parallel with the study of a burning plasma in order to be prepared for the step to a

practical demonstration power plant. These optimization studies are based on, and

contribute 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 to

assure 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 for

fusion 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 the

world 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 the

development 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 the

time for the U.S. to take the steps leading to construction of a burning plasma experiment,
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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 to

bring 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 be

held in summer, 2002, in which the community assesses the scientific and technical

viability of each of the three options, and affirms (or denies) the proposition that the time

to 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. course

of 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 the

uniform 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 by

over 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 the

scientific 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 the

best path or strategy to pursue these burning plasma options. That is the goal of the

present 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 the

strategy we have considered carefully all three burning plasma options investigated at the

2002 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, the

European 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 formulation

of a decisive strategy.

Since its inception, fusion energy science research has been a paradigm for

international collaboration. Throughout its history, fusion research has been a strongly

interacting, 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 OPTIONS

Over 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 have

been proposed to investigate burning plasmas. The Study identified the key scientific and

technological burning plasma issues and opportunities and made assessments of the

abilities 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 in

deuterium-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 as

well 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 and

pulsed cryogenically cooled copper coils as a reduced cost approach to achieve

this mission.

• The overall objective of ITER is to demonstrate the scientific and technological

feasibility of fusion energy. ITER would accomplish this objective by

demonstrating extended burn of deuterium-tritium plasmas with Q at least ten,

with steady-state as an ultimate goal, by demonstrating technologies essential to a

reactor 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 with
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Q greater than five, and the possibility to demonstrate controlled ignition defined

as Q of about thirty.

III.B Scope of Projects

1. Points in Common

The Study concluded that each approach would enable the investigation of the

physics of burning plasma, advance fusion technology, and contribute to the development

of 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, fuel

delivery, exhaust, plasma-facing components, and magnets) at parameters and

plasma 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 technological

contributions in these physics and technology areas, the opportunities offered by the

approaches are quite different. The Study clarified the following distinctions between the

opportunities:

• 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 in

conventional 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 to

plasma technology.

• ITER offers an opportunity for the study of burning plasma physics in

conventional 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-heated

plasmas 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 with

strong shaping and active MHD stability control, and (c) study of removal of

helium 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 have

steady-state heat removal capability.

• ITER would especially address four physics areas: (a) the science of self-heated

plasmas in power plant relevant regimes of small ρ* and high βN, and with the

capability of full non-inductive plasma current drive sustained in near steady state

conditions, (b) exploration of high self-driven plasma current regimes with a

flexible array of heating, current drive, and rotational drive systems, (c)

exploration of alpha particle-driven instabilities in a power-plant-relevant range of

temperatures, and (d) temperature control and removal of helium ash and

impurities 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 the

needed 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 other

outstanding scientific and technical issues relating to each of the three options. Most of

these can be addressed through continuing research and development, including modeling
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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 is

based 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 the

relative “value” of all the tasks necessary for construction to facilitate

international negotiations on task sharing. The cost information is based on a

large 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 to

2002 US dollars, is about $5 billion. The actual cost estimate is to be developed

by each party using its own procedures, including the use of contingency. Thus,

the ITER cost information does not included explicit contingency. In the

recommended 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 engineering

development.

• 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 the

fusion 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 and

allows 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 less

costly integration step that will follow.

• An international tokamak research program centered around ITER, which

includes other performance-extension devices throughout the world, has the

highest 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 lead

to the shortest development time to a demonstration power plant.

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

IV. THE RECOMMENDED STRATEGY

This 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 the

development 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 scientific

opportunities offered by the three options for a burning plasma experiment are delineated

in Section III. These three sections together establish the framework for our

recommended strategy.
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IV.A Basis for the Strategy

The recommended strategy follows from the following set of findings that derive

from 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 the

development 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 technological

challenge 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 and

technological 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 and

technology 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 the

development of low-activation materials and fusion technology. A core science and

technology program focuses on fundamental understanding, confinement configuration

optimization, and the development of plasma and fusion technologies. These topics are

advanced in the core program through experimental, theoretical, and computational

activities. This core program is essential to the successful and full exploitation of a

burning plasma program. The guidance of the burning plasma program rests on the

knowledge 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, is

insufficient to meet these challenges.

The ITER facility is proposed as an international project at power-plant scale with a

comprehensive 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 size

and 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 array

of 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 in

a wide array of technologies needed for fusion energy development. The operation and

study of a power-plant scale facility that integrates burning plasmas, near steady-state,
15

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 and

engineering 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 the

plasmas 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 not

designed to be the sole burning plasma facility in the world.

IGNITOR offers the opportunity for an early study of the strongly coupled

physics 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 to

different 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 in

experimental capabilities. Viable and aggressive development paths have been

formulated in which either ITER or FIRE form the primary and first burning plasma

experiment. In either case, additional key elements are needed, although there are

differences 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). Both

could contribute to, and benefit from, an interaction with the core science program, which

aims 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 is

appropriate.

IV.B Major Recommendations

Since ITER is at an advanced stage, has the most comprehensive science and

technology program, and is supported internationally, we should now seek to join
16

the ITER negotiations with the aim of becoming a partner in the undertaking, with

technical, programmatic and timing considerations as follows:

The desired role is that the U.S. participate as a partner in the full range of

activities, including full participation in the governance of the project and the

program. 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 access

to 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 of

likelihood could include submission to the partner governments of an

agreement 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 with

other major international facilities.

A strong core science and technology program is essential to the success of the

burning 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.
17

V. PRIORITIZED OBJECTIVES FOR U.S. PARTICIPATION IN ITER

Achievement of the U.S. burning plasma goals requires that the implementation

of the recommended strategy be guided by clear prioritized objectives, as detailed in

Appendix 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, to

contribute to the science base for the full range of toroidal confinement

configurations;

(2) to develop enabling technology that supports the burning plasma research and

positions the U.S. to more effectively pursue burning plasma research;

(3) to advance fusion energy technologies, to contribute to the technology base

necessary for a demonstration fusion power plant; and

(4) to increase involvement of U.S. industry in the fusion program, both in design and

fabrication 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 and

participate 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 of

experiments and in benchmarking of models against ITER data;

(e) opportunities for the U.S. to develop and contribute equipment during the

construction and operations phases of the device, and to have access to

engineering 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 the

baseline;

(g) opportunities to participate in fusion energy technology activities such as the

development and testing of blanket modules.
18

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/.
19

APPENDICES
20

A. FUSION PROGRAM INTEGRATION

The 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 of

fusion science, technology and plasma confinement innovations through a portfolio

approach, and the pursuit of burning plasma physics and fusion energy development as a

partner 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 the

integration 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, the

burning 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 with

the requisite data base required for extrapolation to the burning plasma regime, other

configurations may be more desirable for ultimate deployment as power sources. It is

therefore 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 and

technologies, 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 the

burning plasma program. Predictions on the confinement, stability properties and

dynamics 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 has

come from the core program. Moving forward with a burning plasma experiment requires

experimental scientists, engineers, and theorists and computational scientists from this

core to design experiments and interpret the results.
21

A.2 Burning Plasma Studies Within the Overall Fusion Energy Sciences Program

The creation and control of a magnetically confined burning plasma is a scientific

and 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 to

handle 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 and

challenges associated with a major research and development step.

Scientific flexibility, excellent diagnostics, and close coupling to theory and

simulation 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 to

magnetic 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, and

addresses remaining technology issues. The physics basis for a tokamak burning plasma

experiment will benefit from further understanding of such critical issues as the structure

of 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 role

in ensuring the success of a burning plasma experiment in terms of science and

technology output.

A.3 Strengthening the Core Science and Technology Program

To fully realize the investment in a burning plasma effort and to move towards the

practical 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 and

enhanced 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.
22

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

 Fusion

Research in a well-diagnosed and flexible burning plasma experiment will have

impacts beyond the sphere of fusion science. Plasma pressure profile dynamics in the

presence 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 contribute

to 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, engineering

and systems design. Turbulence studies in burning plasma will provide insights to studies

of neutral fluid turbulence. Studies of magnetic reconnection, important for astrophysical

systems, 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 be

based 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 remote

materials handling and systems maintenance. Finally, developing a predictive capability

of 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 and

technology infrastructure.
23

Fusion research has benefited immensely from international collaboration

worldwide. 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 and

technology. 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, to

address key scientific issues relevant to the success of the burning plasma experiment.
24

B. FUSION DEVELOPMENT PATHS AND THE BURNING PLASMA

 EXPERIMENT

B.1 The Elements in the Fusion Development Path

A burning plasma experiment is a crucial and now missing step on a path to

develop fusion as a practical source of energy. This goal is embodied in realizing a

demonstration power plant (DEMO). A DEMO will employ all the physics and

technologies needed in a commercial power plant at a scale readily extrapolated to

commercial units, will put net electric power on the grid with reasonable availability, and

will 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. fundamental understanding of the underlying science and technology, and

optimization of magnetic configurations,

2. plasma physics research in a burning plasma experiment,

3. high performance, steady-state operation,

4. 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 needed

to advance essential fusion science and technology and to participate effectively in

and to benefit from the burning plasma effort. In particular, the development path

for 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 the

understanding 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 critical

because the innovations required for practical fusion energy can only arise from

continued 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 and

technology for fusion energy will be essential throughout the time of development of

fusion.

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 scientific

issues. Its measurement systems must be sophisticated enough to understand the plasma
25

behavior and it must provide sufficient experimental time to allow thorough parameter

scans 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 on

conventional tokamak physics already in hand, current tokamak research is now focused

on 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-heating

from fusion reactions dominates plasma behavior, is at the frontier of magnetic

fusion energy science. The next major step in magnetic fusion research should be a

burning 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 can

burn 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 and

demonstrate 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 be

able 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 fusion
26

devices appears available to carry forward this research line. Tore-Supra in Europe is an

operating 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 this

research. 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 handling

and 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 in

high reliability, availability, and maintainability in a practical, energy producing system

with low residual radioactivity. Substantial development of the blankets that surround

the 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 high

fluence 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 lead

to the shortest development time to a demonstration power plant. The ITER device lies

on 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 of

operational regimes and plasma measurement capabilities. Its operational flexibility and

long 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 coil

facilities listed above, will provide a firm basis for a steady-state DEMO. ITER will also
27

provide significant initial tests of fusion nuclear technologies. On ITER, tritium handling

experience 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 other

development path elements, from the configuration optimization experiments, and from

the 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 another

configuration. 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 the

conclusion 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 a

much 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 a

significant 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 handling

and 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 research

element will be done on the superconducting facilities listed above. The advanced

tokamak physics basis will be obtained from FIRE, ongoing experiments, and the

superconducting facilities. While the FIRE experiment would contribute to important

plasma technology development like high heat flux plasma facing components and

helium ash pumping, the FIRE development path places much more reliance on the set of

fusion nuclear technology facilities discussed above. The component test facility will

play 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 associated

development path elements. With the benefit of the completion of research on FIRE and

the other research elements, the integration step following FIRE would be more advanced
28

in physics and technical reach than ITER. The DEMO to follow this integration step

would 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 upgrade

of one device into the next within a single facility, perhaps reducing the additional time to

about one-half of one machine generation.

At the decision point in Fig. 2, if the FIRE development path is successful, it is

envisioned 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 to

the tokamak ETF/DEMO.

The FIRE path envisions an internationally coordinated program with

development path needs spread over major nationally run facilities, streamlining the

management approach. However, the international community is concentrating at the

present time on concluding the agreement to proceed with ITER.

IGNITOR

IGNITOR 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 burn

dynamics 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 or

advanced tokamak modes, IGNITOR presents credible advanced performance scenarios

to produce internal transport barriers on a transient basis.
29
30

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 of

overall funding for participation in a BPX is assumed. Rather, this appendix provides a

menu 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 the

international 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 to

construct 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 the

activities required for preparing for operation. Those from the latter would occur in the

longer term and be more scientific, although much valuable technological experience

would be gained from operation and maintenance of a burning plasma experiment.

Among the BPX options currently under consideration -- building FIRE domestically but

with some international participation, participating in ITER internationally or supporting

IGNITOR in Italy1 -- the relative share and balance of these two areas of activities borne

by 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 be

readily identified:

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

 1

 IGNITOR proponents have also suggested the possibility of constructing an Ignitor-like device in the US.
31

• maintaining/increasing the breadth and depth of U.S. capability in fusion related

technologies; and

• increasing U.S. industrial capacity in high-tech areas, especially ones important to

fusion.

• 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; in

which 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 are

nonetheless 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 with

existing U.S. facilities; and

• broadening 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 a

consequence, the U.S. might expect to lead in some areas and support in others, with data

and 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 of

potential 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 and

they are rated low, moderate or high. A “high” rating means that the task will make a

very 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, the

existing US capability to perform the task is rated as high, moderate or low with some

brief 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, to

contribute to the science base for the full range of toroidal confinement

configurations,

(O2) to develop enabling technology that supports the burning plasma research and

positions 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 and

fabrication 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 and

technology 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 the

primary 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) a significant U.S. role in the decision-making regarding the ITER research

program, including overall research directions and selection of experiments;

(R2) opportunities for U.S. researchers from all segments of the U.S. fusion

community (universities, laboratories, and industry) to propose, plan, conduct and

participate in experiments as members of the ITER research team;
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(R3) 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;

(R4) opportunities to apply theory and integrated modeling in design and analysis of

experiments and in benchmarking of models against ITER data;

(R5) opportunities for the U.S. to develop and contribute equipment during the

construction and operations phases of the device, and to have access to

engineering data equal to that of all partners;

(R6) opportunities to propose/develop/design/fabricate/install/operate advanced

diagnostics and enabling technology (e.g., plasma control tools) beyond the

baseline;

(R7) opportunities to participate in fusion energy technology activities such as the

development 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 from

research-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, remote

research 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 a

significant 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 data

acquisition, 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 leading

roles 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 specific

components 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, the

U.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 from

which 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. fund

as contractual milestones are met. (Note: the U.S. and the ILE must structure the

procurements such that the ILE- and contractual-specifications and milestones are

identical and the ILE must grant credit when the U.S. industry delivers products

that meet the contractual specification.)

(F4) “cash contributions,” in which the U.S. provides a small amount of cash to be

controlled by the project for scope and expenses outside the negotiated

procurement 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 the

ILE, 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 performance

of 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 research

decision-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 responsible for the

design/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 be

within the FIRE project.

(A2) FIRE Program Activities would address scope that is outside the FIRE

construction project; examples would include preparations for physics and

technology 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 to

participate in the design and construction phase of FIRE. There may be unique areas of

expertise and capability where a non-U.S. party would wish to participate as a

collaborator 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 research

and 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 topical

task 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 to

those experiments

(R5) proposal/development/design/fabrication/installation/operation of advanced

diagnostics and enabling technology (e.g., plasma control tools) beyond the

baseline

(R6) the opportunity for non-U.S. participants to perform theory and integrated

modeling both in design and analysis of experiments
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(R7) joint work by non-U.S. participants on supporting experiments on non-FIRE

facilities

(R8) 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 form

of “in-kind contributions”, in which the non-U.S. party commits to provide specific

products 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 that

would 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 a

formal 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 the

primary 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 and

beyond the baseline

(R4) the opportunity to perform theory and integrated modeling both in design and

analysis of experiments

(R5) U.S. participation in fusion technology activities such as the development and

testing 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 access

to IGNITOR for associated research. The U.S. would be obligated to provide the

product irrespective of the actual cost to the U.S. To assure completion of scope
37

within the budget, the U.S. must include sufficient contingency in the budget

estimates for “in-kind contributions.”