The U.S. Fusion Program at the Crossroads
The ITER Decision and U.S. Fusion R&D
To keep pace with the cutting edge of fusion research, the United States must participate in the planned international research reactor.
The United States must soon decide whether to participate in construction of the International Thermonuclear Experimental Reactor (ITER). ITER is the product of a years-long collaboration among several countries that is both a major advance in fusion science and a major step toward a safe and inexhaustible energy supply for humanity: practical power from fusion.
The decision about joining this international collaboration is evolving within the context of a severely constrained U.S. budget for fusion R&D. The United States is, by default, on the verge of deemphasizing within its national program the successful mainline Tokamak concept that has advanced to the threshold of fusion energy production. Significant participation in ITER is the only way at present in which the United States can remain involved in the experimental investigation of the leading issues of fusion plasma science and in developing technological aspects of fusion energy. The decision has broad implications for the national interest and for future international collaboration on major science projects, as well as for the next 30 years of fusion R&D. It would be tragic for the United States to miss this opportunity, which it has been so instrumental in creating, to benefit fully from collaboration in ITER.
Fusion R&D seeks to create and maintain the conditions under which the sun and the stars produce energy. Most fusion R&D has been concentrated on the toroidal magnetic confinement configuration known as the Tokamak. Scientific achievements in the early Tokamaks, together with the energy crisis of the 1970s, led to increased funding for fusion R&D worldwide, which allowed the building of the present generation of large Tokamak experiments in the United States, Europe, and Japan. The world's nations are currently spending more than $1.5 billion annually (about $600 million in Europe; $400 million in Japan; $230 million in the United States; a large amount in Russia; and smaller expenditures in Australia, Brazil, Canada, China, India, Korea, and so on).
Scientific progress in Tokamak fusion research has been steady and impressive. Researchers had heated plasmas to above solar temperatures by the late 1970s. The "triple product" of the density, temperature, and energy confinement time, which is related to a reactor's ability to maintain a self-sustaining fusion plasma, has increased a thousandfold since the early 1970s and is now within a factor of less than 10 of what is needed for practical energy production. The production of fusion power has increased from a fraction of a watt in the early 1970s to ten million watts.
U.S. fusion program
The U.S. fusion program currently operates two Tokamaks that are producing state-of-the-art scientific results: DIII-D, at General Atomics in San Diego, was designed and built during the 1970s. The newer ALCATOR-CMOD is the most recent in a line of small, relatively inexpensive facilities pioneered at MIT. A third major Tokamak, the TFTR at Princeton Plasma Physics Laboratory, ceased operation in 1997.
As a result of 25 years of intensive development worldwide, the Tokamak configuration has now reached the point where a new facility that would significantly advance the state of the art would cost at least a billion dollars. Twice in the past decade, Congress has rejected proposals to build a new U.S. Tokamak. Once the aging DIII-D is decommissioned, which will probably happen within 5 years, the United States will no longer have a large Tokamak in operation.
The United States has not only failed to build new Tokamak experiments, it has also not adequately supported the operation of the experiments it did build or the complementary parts of the fusion program. After peaking at about $600 million (in 1995 dollars) in the late 1970s, the annual U.S. fusion budget has declined to $232 million this year. As a result, fusion researchers had to abandon many worthwhile efforts. Concentrating on the Tokamak configuration has paid off in terms of scientific advancement, but it has substantially narrowed the scientific and institutional bases of the U.S. fusion program. Several experimental facilities intended to explore alternative magnetic-confinement concepts were shut down prematurely. The fusion technology program was reduced drastically. The broader objectives and the schedule associated with the former goal of practical fusion energy have recently been delayed, replaced by the more limited objective of exploring the underlying science.
If the United States does not support ITER, it will be abandoning the centerpiece of its program and the Tokamak concept at a time when advanced operating modes for achieving enhanced performance and more attractive reactor prospects are rapidly developing. By necessity, the emphasis would shift to alternative confinement concepts for which a state-of-the-art facility is more affordable. Unfortunately, the reason that the cost is lower is that these concepts are at least 20 years behind the Tokamak.
The arguments for federal support of fusion research seem compelling. Fusion promises to be the ultimate energy source for mankind because its fuel supply is virtually limitless. The conceptual designers of future commercial fusion plants project electricity costs in the same range as those projected for nuclear and fossil fuels 50 years from now, although projections so far into the future are not very reliable for either. Of all possible energy sources, fusion seems to have the least potential for adverse environmental impact. There are also numerous spinoff applications of fusion R&D. In short, fusion would seem to be the type of long-term high-payoff R&D that Congress should fund adequately.
But after supporting a successful program that led the world for most of the past 30 years, the federal government is no longer maintaining a first-rank national fusion program. It is not clear whether this is simply because competing claims for scarcer resources have attracted stronger support in Congress or because fusion has fallen out of favor.
One criticism is that "fusion is always 25 years away." There is some truth in this complaint. Fusion plasmas have turned out to be more complex than anticipated by the pioneers of the field. On the other hand, the R&D program proposed by research managers in the 1970s to demonstrate fusion power early in the next century was never funded at anywhere near the level required to achieve such an ambitious objective.
Another criticism is that nobody would want Tokamaks even if they worked because they would be too big and complex to be practical. It is true that if one simply extrapolated from the design of the existing experiments, the result would be a large expensive commercial reactor. For many years, researchers paid little attention to optimizing performance because their focus was on understanding the physics phenomena inside Tokamaks. But researchers have recently demonstrated that the internal configuration can be controlled to achieve substantially improved performance that suggests that more compact reactors may turn out to be practical. The very complexity of the interacting physics phenomena that govern Tokamak performance creates numerous opportunities where further improvements may be achieved in the future.
The ITER project
A landmark in fusion development occurred in the 1980s, when the United States joined with the European Union, Japan, and the USSR in the International Tokamak Reactor (INTOR) Workshop (from 1979 to 1988), and since 1988 in the ITER project, to work collaboratively toward designing and building a large experimental reactor. Since 1992, the partners have been collaborating on an engineering design that could serve as a basis for government decisions to proceed with construction of ITER beginning in 1998. The design and R&D are being coordinated by an international joint central team of about 150 scientists and engineers plus support staff. A much larger number of laboratory, university, and industrial scientists and engineers are members of "home teams" in Europe, Japan, Russia, and the United States. The most recent design report runs to thousands of pages, including detailed drawings of all systems and plant layouts. A final design report is scheduled for July 1998, and the procurement and construction schedule supports initial operation of ITER in 2008.
Technology R&D to confirm the ITER design is being performed in the laboratories and industries of the four ITER collaborators under the direction of the ITER project team. Total expenditures for this R&D over the six years of the design phase will be about $850 million in 1995 dollars. The cost (in 1995 dollars) of constructing ITER is estimated at $6 billion for the components, $1.3 billion for the buildings and other site facilities, $1.16 billion for project engineering and management, and $250 million for completion of component testing. Thus, with an allowance for uncertainty, ITER's total construction cost is estimated at about $10 billion. Subsequent operating costs are estimated at $500 million per year.
After construction, ITER would operate for 20 years as an experimental facility. Initially, the emphasis would be on investigating new realms of plasma physics. ITER would be the first experiment in the world capable of definitively exploring the physics of burning plasmas-plasmas in which most of the power that maintains the plasma at thermonuclear temperatures is provided by the deuterium-tritium fusion events themselves. The second broad objective of ITER is to use the reactorlike plasma conditions to demonstrate the technological performance necessary for practical energy-producing fusion. The superconducting magnet, heating, fueling, tritium handling, and most other systems of ITER will be based on technology that can be extrapolated to a prototypical fusion reactor.
Future fusion reactors must be capable of replenishing the tritium fuel they consume, but this technology will not be sufficiently developed to incorporate into ITER at the outset. Similarly, more environmentally benign advanced structural materials that are capable of handling higher heat fluxes are also being developed, but not in time for use in constructing ITER. Thus, the third major objective of ITER is to provide a test facility for nuclear and materials science and technology development.
After ITER would follow a fusion demonstration reactor (DEMO) intended to establish the technological reliability and economic feasibility of fusion for producing electrical power. The national plans have been for the DEMO to follow 15 to 25 years after ITER initial operation in order to exploit the information developed in ITER. Each party presumably would build its own DEMO as a prototype of the system it plans to commercialize, but further collaboration at the DEMO stage is also possible.
A Tokamak DEMO will be smaller than ITER for two reasons. First, ITER is an experimental device that must include extra space to ensure flexibility and to allow for diagnostics and test equipment. Second, and more important, advanced Tokamak modes of plasma operation can be explored in ITER and subsequently used to design a DEMO based on improved performance characteristics. A recent study showed that the DEMOs could be designed at about half the ITER volume.
It is not widely recognized that the plasma performance and technology demonstrated in ITER will be sufficient for the construction of large-volume neutron sources that could meet several national needs, including neutron and materials research, medical and industrial radioisotope production, tritium production, surplus plutonium disposition, nuclear waste transmutation, and energy extraction from spent nuclear fuel. Recent studies have shown that it would be possible to use a fusion neutron source based on ITER physics and technology for such applications.
Time to decide
The time for decisions about moving into the ITER construction phase, about the identity and contributions of the parties to that phase, and about the siting of ITER is close at hand. The four partners are currently involved in internal discussions and informal interparty explorations. The prime minister of the Russian Federation has already authorized negotiations on ITER. The chairman of the Japan Industry Council has called publicly for locating ITER in Japan, and a group of prominent Japanese citizens is working to develop a consensus on siting. In 1996, the European Union Fusion Evaluation Board, an independent group of fusion researchers, declared that "starting the construction of ITER is therefore recommended as the first priority of the Community Fusion Program" and that "ITER should be built in Europe, as this would maintain Europe's position as world leader in fusion and would be of great advantage to European industry and laboratories."
To date, the United States has been the least forthcoming. Reductions in the fusion budget have already forced the United States to trim its annual contribution to the ITER design phase from its promised $85 million to $55 million. Officials in the U.S. Department of Energy (DOE) have discussed informally with their foreign counterparts the possibility of participating in ITER construction with a $55 million annual contribution, which would cover about 5 percent of the total construction cost. It is unlikely that the ITER construction can go forward with this minimal U.S. contribution.
In fact, this U.S. position has been a major factor contributing to the inability of the sponsoring governments to move toward an agreement to ensure that construction can begin as planned in July 1998, when the present ITER design agreement ends. As a result, informal discussions about a three-year transition period between the end of the design phase and the formal initiation of construction have recently intensified. Such a transition phase, if adequately funded, could accomplish many of the tasks that would normally be accomplished in the first years of the construction phase but would inevitably have an impact on the momentum, schedule, and cost of the project.
Part of the decision about building ITER is selecting a site. To date, Japan, Canada, France, Sweden, and Italy have informally indicated an interest in playing host to ITER, whereas the United States has indicated that it will not offer a site.
The United States should reconsider. The Savannah River Site (SRS) in South Carolina satisfies all ITER site requirements with no need for design modifications, and other government nuclear laboratories such as Oak Ridge in Tennessee also meet the site requirements. SRS's extensive facilities, which include sea access for shipping large components, would result in a site credit (a cost for a new site that would be unnecessary because of existing facilities)] of about $1 billion. SRS's existing expertise and infrastructure are directly relevant to ITER needs and would complement the fusion expertise of the ITER project team. This SRS expertise and infrastructure must be maintained in any case for national security; they could be used by ITER for little additional real cost.
There are at least two tangible advantages to hosting ITER. First, fusion engineering expertise and infrastructure will be established at the host site. The host country subsequently will be able to use this residual expertise and infrastructure for building and operating one or more fusion neutron source facilities and/or to construct a DEMO. Second, estimates suggest that ITER will contribute $6 billion to the local economy over a period of 30 years.
A bonanza of benefits
Scientific and technical. The primary objective of the U.S. fusion program is to study the science that underlies fusion energy development. ITER offers the United States a way of participating in the investigation of the leading plasma science issues of the next two decades for a fraction of the cost of doing it alone. ITER will provide the first opportunity to study the plasma regime found in a commercial fusion energy reactor, the last major frontier of fusion plasma science. Under the present budget, participation in ITER would seem to be the only way in which the United States can maintain significant participation in the worldwide Tokamak experimental program, which is far advanced by comparison with other confinement configurations. In short, participation in ITER is actually the only opportunity for the United States to remain at the forefront of experimental fusion plasma science over the next few decades.
Fusion energy also requires the development of plasma technology and fusion nuclear science and technology. ITER will demonstrate plasma and nuclear technologies that are essential to a fusion reactor in an integrated system, and it will provide a facility for fusion nuclear and materials science investigations. Participation in ITER not only allows the United States to share the costs of these activities but is the only opportunity for the United States to be involved in essential fusion energy technology development. These ITER studies of the physics of burning plasmas and nuclear and materials science, plus the technology demonstrations, are relevant not just to the Tokamak but also to alternate concepts of magnetic confinement.
Industrial. Many of the ITER components will require advances in the state of the art of design and fabrication. Involvement in this process would enhance the international competitiveness of several U.S. high-tech industries and would surely result in a number of spinoff applications, as well as positioning U.S. firms to manufacture such components for future fusion devices. The participation of U.S. firms in ITER device fabrication would be proportional to the U.S. contribution to ITER construction (excluding site costs) and would be independent of site location.
Political. Two decades ago, the countries of the European Community joined forces to build and operate the successful Joint European Torus fusion experiment, which served the larger political purpose of a major collaborative project at the time of the formation of the European Community. ITER could provide a similar prototype for collaboration on scientific megaprojects among the countries of the world, leading to enormous savings in the future. ITER is perhaps unique among possible large collaborative science projects in that it has been international from the outset. ITER characteristics and objectives were defined internationally, its design has been carried forward by an international team, and the supporting R&D has been performed internationally. ITER represents an unprecedented international consensus.
The U.S. ITER Steering Committee recently completed a study of possible options for continued U.S. participation in ITER. It concluded: "The U.S. fusion program will benefit from a significant participation in ITER construction, operation and testing, and particularly from a level of participation that would enable the U.S. to influence project decisions and have an active project role." An important finding of this study is that, by concentrating contributions in its areas of strength, the U.S. could play so vital a role in the project that it might be able to obtain essentially full benefits while contributing as little as $120 million annually (one-sixth of the ITER construction cost, exclusive of site costs), provided that the other three parties would agree to such a distribution of effort.
The ITER design is based on extrapolation of a large body of experimental physics and engineering data and on detailed engineering and plasma physics analyses. The overall design concept and the designs for the various systems have evolved over 25 years. The physics extrapolation from the present generation of large Tokamaks to ITER is no larger than extrapolations from the previous to present generations of Tokamaks: a factor of four in plasma current and a factor of three in the relevant size parameter.
A large fraction of the world's fusion scientists and engineers, in addition to some 250 who are full-time members of the ITER joint central team and the home teams of the four partners, have helped develop the technological basis for the ITER design and also reviewed that design and the supporting R&D. Perhaps a thousand fusion scientists and engineers in the national fusion programs of the ITER participants are involved part-time. Aspects of the design have been presented and discussed in hundreds of papers at technical meetings. International expert groups make recommendations to the ITER project in several areas of plasma physics. An ITER technical advisory committee of 16 prominent senior fusion scientists and engineers who are not otherwise involved in the ITER project meet two to four times per year to review the design and supporting R&D. Each of the four ITER parties has one or more ITER technical advisory committees.
The ITER conceptual design (1990) was reviewed by about 50 U.S. fusion scientists and engineers independent of ITER; similar reviews were held by the other three ITER parties. The ITER interim design (1995) was reviewed by the ITER technical advisory committee, by formal review committees within the other three parties, and by various groups within the United States.
The ITER detailed design (1996) was recently subjected to a four-month in-depth review by a panel of the U.S. Fusion Energy Science Advisory Committee (FESAC). The report of the FESAC panel, which was made up of about 80 scientists and engineers, most of whom were not involved in ITER, concluded: "Our overall assessment is that the ITER engineering design is a sound basis for the project and for the DOE to enter negotiations with the Parties regarding construction. There is high confidence that ITER will be able to study long pulse burning plasma physics under reduced conditions as well as provide fundamental new knowledge on plasma confinement at near-fusion-reactor plasma conditions. The panel would like to reaffirm the importance of the key elements of ITER's mission-burning plasma physics, steady-state operation, and technology testing. The panel has great confidence that ITER will be able to make crucial contributions in each of these areas."
An independent review of the detailed design by a large committee in the European Union concluded that "The ITER parameters are commensurate with the stated objectives, and the design provides the requisite flexibility to deal with the remaining uncertainties by allowing for a range of operating conditions and scenarios for the optimization of plasma performance." A similar Russian review noted that "the chosen ITER physics parameters, operation regimes and operational limits seem to be optimal and sufficiently substantiated." Japan is also carrying out a similar technical review.
We must keep in mind, however, that ITER is an experiment. Its very purpose is to enter unexplored areas of plasma operation and to use technologies not yet proven in an integrated fusion reactor system; by definition, there are some unresolved issues. Moreover, a major project such as ITER, which would dominate the world's fusion R&D budgets for three decades, is a natural lightning rod for criticism by scientists with a variety of concerns and motivations. Some scientists have raised questions about ITER. Their concerns generally fall into one of two categories: They suggest either that the plasma performance in ITER may not be as good as has been projected or that ITER is too ambitious in trying to advance the state of the art in plasma physics and technology simultaneously. These concerns are being addressed in the ITER design and review process. In sum, the preponderance of informed opinion to date is that the ITER design would meet its objectives.
The right choice
Alternatives to ITER have been discussed. For example, the idea of addressing the various plasma, nuclear, and technology issues separately in a set of smaller, less costly experiments is appealing and has been suggested many times. This idea was undoubtedly in the minds of the President's Council of Advisors on Science and Technology (PCAST) when they recently suggested, in the face of the then-impending cut in the fusion budget, that the United States propose to its ITER partners that they collaborate on a less ambitious and less costly fusion plasma science experiment. A subsequent study by a U.S. technical team estimated that PCAST's proposed copper magnet experiment would cost half as much as ITER but would accumulate plasma physics data very slowly and would not address many of the plasma technology issues nor any of the nuclear science and technology issues. The PCAST suggestion was informally rejected by the other ITER partners. Other manifestations of a copper magnet experiment with purely fusion plasma science objectives have been rejected in the past, formally and informally, as a basis for a major international collaboration.
The ITER technical advisory committee and the four ITER partners, acting through their representatives to the ITER Council, recently once again endorsed the objectives that have determined the ITER design: "The Council reaffirmed that a next step such as ITER is a necessary step in the progress toward fusion energy, that its objectives and design are valid, that the cooperation among four equal Parties has been shown to be an efficient framework to achieve the ITER objectives and that the right time for such a step is now." The report of the independent 1996 European Union Fusion Evaluation Board states "Fusion R&D has now reached a stage where it is scientifically and technically possible to proceed with the construction of the first experimental reactor, and this is the only realistic way forward." In sum, there is broad international agreement that ITER is the right next step.
What is to be done
Given the present federal budget climate, considerable leadership will be needed to realign the evolving government position on ITER and the national fusion program with what would seem to be the long-term national interest. I suggest the following actions:
- The U.S. government should commit to participation in ITER construction and operations as a full partner and should announce in 1997 its willingness to enter formal ITER negotiations. The U.S. contribution to ITER should be increased from the present $55 million annually for the design phase to $100 to $150 million annually by the start of the construction phase. ITER construction funding should be budgeted as a line item separate from the budget of the U.S. national fusion program in order to ensure the continued strength of the latter.
- The U.S. government should support the initiation of the ITER construction phase immediately after the end of the Engineering Design Activities agreement in July 1998. If a transition phase proves at this point to be a political necessity, the U.S. government should work to ensure that the transition phase activities are adequately supported to minimize delay in the project schedule.
- At least $300 to $350 million annually is necessary to allow the United States to benefit from the opportunity provided by ITER for plasma physics and fusion nuclear and materials science experimentation and for fusion technology development, as well as to carry out a strong national program of fusion science investigations. This would make total annual U.S. fusion spending $400 to $500 million (in 1995 dollars) during the ITER construction period.
- The U.S. government should prepare a statement of intent offering to host ITER and transmit it to its partners by the due date of February 1998. One of the government nuclear laboratory sites should be identified for this purpose. The site costs for ITER are estimated at $1.3 billion, and site credit for existing infrastructure and facilities at a site such as SRS could be near $1 billion. Because it has suitable existing facilities, the United States could host ITER as a significant part of its contribution to the project without a major up-front cash outlay.
R. W. Conn et al., Review of the International Thermonuclear Reactor (ITER) Detailed Design Report, panel report to Fusion Energy Sciences Advisory Committee (1997).
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J. Peerenboom et al., Economic Impacts on the United States of Siting Decisions for the International Thermonuclear Experimental Reactor. Report ANL/DIS-2, Argonne National Laboratory, Argonne, Ill., 1996).
P. H. Rutherford, The Physics Role of ITER. Princeton Plasma Physics Laboratory report PPPL-3246 (1997).
W. M. Stacey, The ITER Decision. Georgia Institute of Technology report GTFR-133 (1997).
Weston M. Stacey is the Callaway Regents' Professor of Nuclear Engineering at the Georgia Institute of Technology. He has chaired the U.S. ITER Steering Committee since 1990.