D
Fusion Community Recommendations
The fusion community has been involved in many assessments of the best path for fusion science as it moves toward developing fusion as an energy source. Most recently these assessments have involved the publication of the DOE Fusion Energy Sciences Advisory Committee (FESAC) Review of Burning Plasma Physics (September 2001); the convening of a community workshop in Snowmass, Colorado (July 2002); the commissioning of a FESAC report, A Burning Plasma Program Strategy to Advance Fusion Energy (September 2002); and another FESAC report, A Plan for the Development of Fusion Energy (March 2003). The most prescient elements and recommendations of these efforts are presented in this appendix as summaries prepared by the committee, with excerpts from the respective reports as appropriate.
FREIDBERG REPORT
In October 2000, FESAC was charged with carrying out a review of burning plasma physics. Reporting in September 2001, the FESAC panel led by Jeffrey Freidberg of the Massachusetts Institute of Technology produced a report with five recommendations.1 The panel concluded that “NOW is the time for the U.S. Fusion Energy
Sciences Program to take the steps leading to the expeditious construction of a burning plasma experiment” and that “funds for a burning plasma experiment should arise as an addition to the base Fusion Energy Sciences budget.”2 The report suggested that the program should establish what the panel called “a proactive U.S. plan on burning plasma experiments.”3 To that end, the report said, a workshop should be held for the critical scientific and technological examination of proposed burning plasma experimental designs and to provide crucial community input and endorsement to the planning activities undertaken by FESAC. Specifically, the report said, the workshop “should determine which of the specific burning plasma options are technically viable but should not select among them” and “confirm that a critical mass of fusion scientists believe that the time to proceed is now and not some undefined time in the future.”4 The panel also suggested that the DOE charge FESAC with the mission of forming an “action” panel to select among the technically viable burning plasma experimental options and initiate a review by a National Research Council panel with the goal of determining the desirability as well as the scientific and technological credibility of the burning plasma experiment design by the fall of 2003.
In summary, the panel believed that “understanding burning plasmas would be an immense physics accomplishment of wide scientific significance and would be a huge step toward the development of fusion energy.”5 The panel suggested a course of action that it believed would enable the presentation of an optimal burning plasma experimental plan to the nation no later than July 2004.
SNOWMASS WORKSHOP
Following the FESAC plan, a fusion summer study was organized in Snowmass, Colorado, to take place July 8-19, 2002. The study carried out a critical assessment of major next steps in the fusion energy sciences program in both magnetic fusion energy (MFE) and inertial fusion energy (IFE). The resulting report describes the summer study and its outcomes:
The conclusions of this 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 U.S. and 30 foreign fusion physicists and engineers. The objectives of the Fusion Summer Study were three-fold:
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Review the scientific issues in burning plasmas, address the relation of burning plasma in tokamaks to innovative MFE confinement concepts, and address the relation of ignition in IFE to integrated research facilities.
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Provide a forum for critical discussion and review of proposed MFE burning plasma experiments (IGNITOR, FIRE, and ITER) and assess the scientific and technological research opportunities and prospective benefits of these approaches to the study of burning plasmas.
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Provide a forum for the IFE community to present plans for prospective integrated research facilities, assess the present status of the technical base for each, and establish a timetable and technical progress necessary to proceed for each.6
Here, only the elements of the workshop dealing with MFE are considered. At the end of the 2 weeks the participants completed their task and reached consensus on a set of five conclusions:
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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.
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The three experiments proposed [ITER, FIRE, and IGNITOR] to achieve burning plasma operation range from compact, high field, copper magnet devices to a reactor-scale superconducting-magnet device. These approaches address a spectrum of both physics and fusion technology, and vary widely in overall mission, schedule and cost.
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IGNITOR, FIRE, and ITER would enable studies of the physics of burning plasma, advance fusion technology, and contribute to the development of fusion energy. The contributions of the three approaches would differ considerably.
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IGNITOR offers an opportunity for the early study of burning plasmas aiming at ignition for about one current redistribution period.
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FIRE offers an opportunity for the study of burning plasma physics in conventional and advanced tokamak configurations under quasi-stationary conditions (several current redistribution time periods) and would contribute to plasma technology.
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ITER offers an opportunity for the study of burning plasma physics in conventional and 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.
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R. Bangerter, G. Navratil, and N. Sauthoff, 2002 Fusion Summer Study Report, 2003, available online at http://www.pppl.gov/snowmass_2002/snowmass02_report.pdf, p. 2. Accessed September 1, 2003. |
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There are no outstanding engineering-feasibility issues to prevent the successful design and fabrication of any of the three options. However, the three approaches are at different levels of design and R&D. There is confidence that ITER and FIRE will achieve burning plasma performance in H-mode based on an extensive experimental database. IGNITOR would achieve similar performance if it either obtains H-mode confinement or an enhancement over the standard tokamak L-mode. However, the likelihood of achieving these enhancements remains an unresolved issue between the assessors and the IGNITOR team.
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The development path to realize fusion power as a practical energy source includes four major scientific elements [see Figure D.1 in this appendix]:
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Fundamental understanding of the underlying science and technology, and optimization of magnetic configurations
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Plasma physics research in a burning plasma experiment
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High performance, steady-state operation
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Development of low-activation materials and fusion technologies.7
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PRAGER REPORT
Following the Freidberg report’s strategy, in February 2002 the DOE Office of Science’s Acting Director, James Decker, charged FESAC to establish a high-level panel to recommend a strategy for burning plasma experiments. The 47-member panel, chaired by Stewart Prager of the University of Wisconsin at Madison, met in Austin, Texas, August 6-8, 2002, and its strategy recommendation report was adopted by FESAC on September 5, 2003.8 The panel based its recommendations on the Snowmass assessment, with the aim of presenting a strategy to enable the United States to “proceed with this crucial next step in fusion energy science.”9 The report states:
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
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R. Bangerter, G. Navratil, and N. Sauthoff, 2002 Fusion Summer Study Report, 2003. Available online at http://www.pppl.gov/snowmass_2002/snowmass02_report.pdf, pp. 3-8. Accessed September 1, 2003. |
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Fusion Energy Sciences Advisory Committee, A Burning Plasma Program Strategy to Advance Fusion Energy, Washington, D.C.: U.S. Department of Energy, 2002 (hereafter referred to as FESAC, A Burning Plasma Program Strategy to Advance Fusion Energy). |
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FESAC, A Burning Plasma Program Strategy to Advance Fusion Energy, p. 3. |
burning plasma program, providing the necessary knowledge base and scientific work force.10
The panel made two primary findings:
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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.
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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.11
With this background, the panel put forth the following strategy recommendations:
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Since ITER is at an advanced stage, has the most comprehensive science and technology program, and is supported internationally, [the United States] 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.
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.
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Since FIRE is at an advanced pre-conceptual design stage, and offers a broad scientific program, [it] 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.
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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.
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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.
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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.
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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.
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A burning plasma science program should be initiated by the OFES with additional funding in FY04 sufficient to support this strategy.12
GOLDSTON REPORT
With the completion of the FESAC part of the Freidberg report’s plan of action, and with the continuing work of this National Research Council committee, DOE charged FESAC to develop a plan for the deployment within 35 years of a fusion demonstration power plant, leading to the commercial application of fusion energy by midcentury. The plan was developed by a committee under the leadership of Robert Goldston of Princeton Plasma Physics Laboratory. It dealt with development paths for both MFE and IFE, although the present discussion focuses only on the MFE aspects of the report.
The Goldston report,13 adopted by FESAC on March 5, 2003, goes well beyond the DOE plan for a magnetic fusion burning plasma experiment envisioned in the charge of the NRC’s Burning Plasma Assessment Committee (BPAC), including the consideration of inertial fusion energy. Therefore, many aspects of the plan are
not relevant to the charge before BPAC, although aspects of the MFE development plan as laid out in the Goldston panel report are relevant to this committee’s work.
According to the Goldston report, key elements of its plan are as follows:
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To develop fusion energy on the 35-year timescale, it is “imperative to have a strong balanced program that develops fusion science and technology in parallel.”14
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The report also says that “additional funding” is needed to “participate in the construction and utilization of ITER, or, if ITER does not advance to construction, to complete the design of and to construct the domestic FIRE experiment.”15
Objectives selected from the report that are relevant to the implementation of a U.S. plan for a burning plasma experiment include these:
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From the present to 2009
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Begin construction of ITER, and develop science and technology to support and utilize this facility. If ITER does not move forward to construction, then complete the design and begin construction of the domestic FIRE experiment.
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Test fusion technologies in non-fusion facilities in preparation for early testing in ITER, including first blanket modules, and to support configuration optimization.16
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From 2009 to 2019
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Demonstrate burning plasma performance in NIF and ITER (or FIRE).
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Obtain plasma and fusion technology data for MFE CTF [Component Test Facility] design, including initial data from ITER test blanket modules.
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Demonstrate efficient long-life operation of IFE and MFE systems, including liquid walls.17
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The report finds that the U.S. fusion energy sciences program is still suffering from the budget cuts of the mid-1990s and the loss of what it terms “a clear national commitment to develop fusion energy,”18 with concomitant increasing difficulty in retaining technical expertise in key areas. The Goldston plan also estimates that the fusion budget needs to double over the next 5 years to begin to implement the development path foreseen in the report.