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Introduction

Fusion energy offers the prospect of abundant, virtually unlimited energy, and the United States and many nations around the world have made enormous progress toward achieving fusion energy. Many of the complex physical processes of magnetically confined plasma are now understood, and the first phase of construction for the International Thermonuclear Experimental Reactor (ITER) is more than half complete. With the initial operation of ITER scheduled to begin within a decade and with the expectation, 10 years later, that controlled fusion will be demonstrated, now is the right time for the United States to develop plans to benefit from its investment in burning plasma research and take steps toward developing fusion electricity for the nation’s future energy needs.

This report of the Committee on a Strategic Plan for U.S. Burning Plasma Research of the National Academies of Sciences Engineering, and Medicine presents guidance on a strategic plan for a U.S. research program of burning plasma science and technology directed toward realizing economical fusion energy. It builds on the committee’s interim report,¹ which provided assessments of the importance of burning plasma research to the development of fusion energy and of the current status of burning plasma research in the United States. Although significant scientific and engineering challenges are described, the committee concluded that the knowledge developed through decades of fusion research is now sufficiently advanced to propose a path to demonstrate fusion-generated electricity within the next several decades. This strategy requires continued partnership in the international effort and strengthened research within the United States. Many technical details of the proposed strategy need further development and input from

the U.S. fusion energy science community. Nevertheless, based on the advanced state of understanding the science of magnetic confinement, new developments in superconducting magnets and advanced manufacturing methods, the considerable expert input received, and the committee’s expertise, the committee concludes that a research pathway that includes study of a burning plasma and leads to the construction of a compact fusion pilot plant at the lowest possible capital cost is technically sound and strategically warranted. This strategic guidance can be developed for two scenarios: if the United States continues as a partner in the ITER project, or if it does not. However, if the United States decides to withdraw from the ITER project, the United States would need to design, license, and construct an alternative means to gain experience creating and controlling an energy-producing burning plasma. Without ITER participation, the scale of research facilities within the United States would become larger and the achievement of electricity production from fusion in the United States would be delayed.

The following introduction is organized into four sections: (1) a brief background, (2) a summary of the committee’s approach to its task, (3) a summary of the committee’s assessments within the interim report, and (4) an outline and guide to the overall structure of this final report, including the committee’s findings and recommendations.

BACKGROUND

Fusion is the process that powers the Sun and thereby enables life on Earth to exist. It occurs when hydrogen-like particles at extremely high temperature fuse to make a heavier element, like helium. In this process energy is released, eventually appearing as heat. Fusion electrical power plants would produce no carbon-based pollutants, have minimal long-lived radioactive waste, and benefit from an almost limitless fuel supply. The most successful concept and the subject of this report is a fusion power plant consisting of a steadily burning plasma confined by a very strong magnetic force field within a donut-shaped vessel. In order for more power to be released by fusion reactions than needed to maintain the temperature of the burning plasma, above 100 million K, the burning plasma must have sufficiently large size and strong magnetic field so that the energy released by fusion reactions provides most of the power needed to keep the plasma hot. Although significant fusion power has been generated for short periods in the laboratory, a burning plasma, which is heated predominately by fusion reactions, has never been created. This requires construction of a burning plasma experiment such as the ITER. While ITER is a science and technology experiment, a future fusion power system will be built with additional advanced technologies that will allow uninterrupted operation, guide escaping plasma heat from the burning plasma out of the vessel in a controlled way, produce the fusion fuel in blankets that surround the burning

plasma, and convert the radiating energy from fusion to electricity in the same way as in existing power plants.

The United States became an ITER partner in 2007 after signing a binding international agreement² with China, the European Union, India, Japan, the Republic of Korea, and Russia to build and operate a burning plasma experiment at the scale of a power plant. ITER is a large and ambitious project that integrates multiple advanced technologies and combines the scientific and engineering expertise, industrial capacity, and financial resources of several nations. As a burning plasma experiment, ITER is a critical step along the path to advance the science and technology of a fusion power source. The first phase of ITER construction is now more than half complete. The ITER Organization plans for initial operation of the facility by the end of 2025.

The decision to construct ITER was a milestone in fusion energy research. Fusion scientists had successfully built, operated, and studied a series of experiments with strong magnetic fields and increasing size. Using these experiments, they learned how to confine and control high-pressure plasma at temperatures exceeding 100 million K. In the largest experiments,^3,4 significant fusion power was produced for seconds, and some of the processes expected in a burning plasma were studied at the temperatures and pressures required for fusion energy. The 2004 report of the the Burning Plasma Assessment Committee, Burning Plasma: Bringing a Star to Earth,⁵ concluded that the global fusion community was technically and scientifically ready to undertake a burning plasma experiment like ITER. Since that report, research has further increased confidence that ITER will achieve its scientific mission and allow scientific studies of burning plasma at the power plant scale.⁶

When fully completed, ITER will be capable of producing energy comparable to the output of a power plant and will allow study of many of the interconnected science and technology issues needed to develop magnetic fusion energy as a practical source of power. Scientists will use ITER to test methods to control plasma stability, plasma interactions with first wall materials, plasma confinement, and fusion power output. Theoretical predictions of energetic particles produced by fusion reactions and methods to sustain a burning plasma for pulses longer than 5 minutes will be explored and validated. Equally important are gains in fusion engineering science and industrial capability that are resulting from assembly and operation of large superconducting magnets, safe management and recovery of tritium, remote handling of in-vessel components, progress in evaluating fusion blanket options, and experience with large-scale project management.

While experiments with ITER will lead to major gains along the path to fusion energy, additional science and engineering challenges need to be addressed before fusion power can be produced in a reliable, economical, and socially acceptable way. In a commercial system, the fusion power density would need to increase and uninterrupted operation should be available for more than a year. Energetic

neutrons impinging on the surrounding wall and the escaping heat from the plasma need to be handled reliably. The lithium-containing blankets that surround the plasma need to safely produce unprecedented quantities of tritium, the heavy isotope of hydrogen. Technology innovations should be encouraged and developed to simplify maintenance and lower construction cost. Any strategic plan for fusion power requires both study of a burning plasma experiment and research beyond what will be done in a burning plasma experiment to improve and fully enable commercial fusion power.

National strategic plans leading to the demonstration of fusion power have been adopted by our international partners. Similar strategies have been discussed within the United States in the past. However, for more than a decade, the United States has not had a long-term strategic plan for fusion energy. This report provides guidance for such a plan for the United States.

The U.S. Department of Energy’s (DOE’s) Office of Fusion Energy Sciences (FES) presented its current vision for fusion research to Congress in 2015.⁷ The overall mission is to “expand the fundamental understanding of matter at very high temperatures and densities and build the scientific foundation needed to develop a fusion energy source.” U.S. fusion research emphasizes two frontiers in burning plasma science: “the physics of self-heated burning plasma state” using ITER as the vehicle for gaining access to this state, and the “great scientific challenge for fusion is to develop materials that can tolerate the extreme conditions created by burning plasma in a fusion reactor.” The majority of the DOE/FES program budget contributes to developing the predictive understanding needed for ITER operations and providing solutions to high-priority ITER research needs. A smaller element, called “Discovery Plasma Science,” represents about 15 percent of the annual fusion budget and supports research that advances fundamental understanding of ionized matter, or plasma, in support of non-fusion applications. Nevertheless, these fundamental plasma studies inform both non-fusion and fusion applications. As applied to fusion energy science, they develop and test underlying concepts that underpin fusion plasma theory and simulation efforts and assist in the development of validated simulation capabilities to predict fusion plasma performance and behavior. The DOE Office of Science has not presented a plan for research and technology programs needed to progress beyond ITER to a source of fusion power.

The U.S. research focus on ITER has resulted in significant burning plasma research advances and improved confidence in ITER burning plasma performance. Examples of new progress include improved understanding and modeling of plasma confinement, demonstration of long-pulse magnetic confinement, achievement of high plasma pressure comparable to values expected in ITER, improved understanding of plasma exhaust processes, and successful demonstration of several techniques to control transients. However, other fusion energy science and technology efforts within the United States that did not directly support ITER have

been reduced or eliminated. Fusion technology efforts were reduced and domestic experimental facilities were closed, limiting scientific and engineering opportunities within the United States and weakening the potential to build expertise in fusion science and technology and guide needed research alongside ITER.

The absence of a long-term research strategy for the United States is particularly evident when compared to the plans of our international partners. The Committee to Review the U.S. ITER Science Participation Planning Process observed in its 2009 National Research Council report that “international partners in ITER are explicitly organized toward developing fusion energy and a demonstration fusion power plant (DEMO). This focus gives them a clear goal for their development of fusion power.”⁸ The 2009 report further recommended that “existing gaps in planning for a demonstration power plant” should be addressed in further development of U.S. DOE planning. EUROfusion (the consortium agreement of research organizations and universities from 26 European Union countries plus Switzerland, Ukraine, and formerly the European Fusion Development Agreement) is guided by a roadmap to supply fusion electricity to the grid by the 2050s.⁹ Similar national roadmaps leading to the demonstration of fusion power guide research in China¹⁰ and Japan.¹¹ This committee’s interim report also noted the importance of strategic planning to guide national research and innovation programs, engage industrial partners, and set national priorities and concluded, “if the United States seeks to continue its pursuit for abundant fusion power, the development of a national strategic plan for fusion energy that spans several decades is necessary.”¹²

Since joining the ITER project, the U.S. fusion community and its advisory committee, DOE’s Fusion Energy Sciences Advisory Committee (FESAC),¹³ have responded to requests from the Office of Science to identify the issues arising in a path to fusion demonstration, with ITER as a central part of that effort, and to prioritize the additional interconnected scientific and technical questions to be answered. Appendix C presents a summary of these strategic planning activities conducted from 2001 to 2018. Fourteen FESAC reports and four community workshops sponsored by the DOE Office of Science are summarized. These reports recommended programs of research to address all of the scientific challenges of fusion energy including fusion engineering, materials science, and plasma physics.

One difficulty for recent U.S. fusion energy strategic planning has been the substantial growth in ITER construction costs and schedule slippage. In response to cost and schedule concerns, the ITER Council charged an independent team, chaired by William Madia, former director of Oak Ridge National Laboratory and Stanford University vice president for the SLAC National Accelerator Laboratory, to determine the causes for ITER’s cost increases and schedule delays and to make management recommendations. These recommendations resulted in significant management improvements by the ITER Council and the appointment of Bernard Bigot as the new ITER director in March 2015. The ITER Council approved a

new updated long-term schedule to first plasma in June 2016, and DOE was able to approve the project execution plan for U.S. contributions to ITER in January 2017.¹⁴ A measure of the success of ITER’s management reforms is the fact that 2 years after the creation of the updated long-term schedule, the project remains on schedule for first plasma in 2025, and since January 2016, has achieved all 33 scheduled project milestones.¹⁵

The preceding paragraphs and the additional background within Appendix C present the context for the committee’s study and its strategic guidance for burning plasma science and technology directed toward realizing fusion energy. On the one hand, the U.S. fusion energy science program has made leading advances in burning plasma science that have substantially improved our confidence in the success of ITER and our ability to learn a great deal from its operation. On the other hand, the interconnected science and technology needed for fusion are not fully developed. Many challenging questions still need to be answered through scientific discovery and dedicated interdisciplinary study in plasma physics, materials science, fusion nuclear technology, and engineering science. New research facilities and initiatives need to be designed and constructed to carry out the additional research needed to realize fusion electricity. Long-term goals should be set so that priority choices can be made. The U.S. research portfolio will need to evolve in time as existing research facilities are phased out as new ones are implemented.

To be compelling, a new strategy should incorporate technical innovations and insights that enable a lower cost development path than was proposed in past strategic plans. Also, a compelling plan should take into consideration ITER’s updated management and schedule and allow cost-effective study of both a burning plasma experiment and the research and technology programs needed beyond what is done in a burning plasma experiment. After adopting a nationally endorsed strategic plan for delivery of fusion energy, the United States can better set research priorities, promote innovation in fusion science and technology targeted to improve the fusion power system as a commercial energy source, and attract the talented scientists and engineers who will drive research toward commercially viable fusion reactor designs. Describing the elements of this compelling plan is the purpose of this final report.

COMMITTEE APPROACH

In the course of developing its strategic guidance, the committee considered past strategic plans proposed for the United States, the strategic plans of other nations, recent developments, and the input from community experts. The committee first worked to understand whether the science and technology of magnetic fusion has advanced sufficiently to justify adopting a national plan toward realizing fusion power for the United States and how a national strategic plan developed today is

different from past strategic plans. This required understanding the progress and challenges for magnetic fusion energy, the status and schedule of the ITER project, the potential contributions from other international research activities, and the opportunities for progress within the Unites States. The committee then set out to define the steps required to realize economical fusion energy for the United States in the long term.

As required by the committee’s statement of task (reprinted in Appendix A), the focus of this final report is the advancement of magnetic confinement fusion energy given the U.S. strategic interest in realizing economical fusion energy in the long term. As a consequence, the committee did not comment on questions of program balance within the DOE Office of Science between non-fusion plasma science and research in support of magnetic fusion energy. As this report was being written, the committee noted the start of a new decadal assessment of plasma science by the National Academies¹⁶ that will provide valuable information and guidance on issues that pertain to plasma science to the federal agencies and policy makers in both Congress and the administration.

Past strategic plans¹⁷ proposed for U.S. development of fusion energy consisted of the following four elements: (1) magnetic confinement systems, (2) understanding and controlling a burning plasma, (3) developing materials systems that can withstand the energetic fusion neutrons and the escaping plasma heat impinging on the inner wall, and (4) fusion nuclear technology consisting of a fusion “blanket” that both converts the energy released from fusion reactions to electricity and also creates from lithium the heavy isotope of hydrogen, tritium, which should be safely recovered and used as fusion fuel. Figure 1.1 illustrates one strategic pathway as presented in the 2004 Burning Plasma report.¹⁸ Research from all four elements needs to be completed to inform a future “decision point” leading to the demonstration of fusion power and construction of a DEMO facility. A DEMO would produce electricity, operate routinely, and eliminate all technical barriers to the commercialization of fusion power. Prior to a DEMO decision, both nonnuclear and nuclear fusion research occurs. Nonnuclear research in magnetic confinement systems aims to understand and predict how plasma pressure can be confined by configuring the magnetic pressure imposed from strong superconducting magnets. Nonnuclear technology research includes enabling systems that heat and control a burning plasma, the engineering sciences for strong superconducting magnets, and the techniques to handle the escaping heat from the plasma.

The remaining activities in Figure 1.1 are fusion nuclear facilities: a burning plasma experiment, like ITER; a source of 14 MeV neutrons that would advance scientific understanding of radiation effects phenomena in the materials that will surround a fusion plasma; and a fusion component test facility that will test and develop the lithium-containing fusion “blankets” necessary to create the fusion fuel, tritium, and convert energetic neutron energy into useful heat. Because they

are fusion nuclear facilities, they operate with nuclear operating licenses, like the first-of-a-kind basic nuclear fusion license given to ITER by French Order of February 7, 2012.¹⁹

All strategic plans for fusion energy contain the elements depicted in Figure 1.1. But, today, the sequence of activities can be quite different from Figure 1.1 for several reasons. First, the international fusion research community is now much stronger, having made good progress toward fusion. The ITER international partners have demonstrated world-record achievements in long-pulse plasma confinement and have successfully constructed and operated leading research facilities with superconducting magnets. These experiments have provided increased confidence in the prospect for sustained, uninterrupted fusion power. Second, while past plans required the design, siting, and construction of a burning plasma experiment, today’s planning can build upon the continued progress of the ITER project and the significant investment of the international community already under way. With the schedule of the ITER project newly baselined and on track, strategic plans can

expect that burning plasma studies using ITER will inform the next steps in the development of fusion energy. Third, fusion strategic planning is also different today because of advances in the theoretical understanding of toroidal magnetic confinement and plasma control that provide integrated solutions to optimize the burning plasma regime. Finally, remarkable new technologies, largely developed outside the fusion research effort, promise to reduce the size and cost of future facilities that will demonstrate the production of fusion electricity. Unlike the pathway shown in Figure 1.1, a large DEMO device no longer appears to be the best long-term goal for the U.S. program. Instead, science and technology innovations and the growing interest and potential for private-sector ventures to advance fusion energy concepts and technologies suggest that smaller, more compact facilities would better attract industrial participation and shorten the time and lower the cost of the development path to commercial fusion energy.

The committee reviewed past strategic plans, the advancement in magnetic fusion confinement science, and the recent breakthroughs in fusion-relevant technologies with the goal to develop a new lower-cost roadmap for the United States. The committee asked the following questions:

• Has the science and technology of magnetic fusion advanced sufficiently to justify adopting a national plan toward realizing economical fusion power for the United States?
• With the expected start of ITER experiments within the next decade, will U.S. researchers be ready to benefit from burning plasma experiments and begin the next steps, beyond ITER, toward the demonstration of fusion electricity?
• How can the U.S. program develop a unique research strategy that benefits from the large international effort and avoids the cost of duplicated effort?
• Can advances in modeling, prediction, and simulation be used to make wise facility investments and improve overall research effectiveness?
• Finally, can new technologies, like high magnetic field and high critical temperature superconductors, and new material designs and advanced fabrication, like additive manufacturing, lower the cost of fusion development and provide an affordable plan that builds upon the ITER research experience and is consistent with appropriate long-term funding scenarios leading to fusion electricity?

The committee answered these questions through deliberation and through detailed consideration of technical input from the fusion research community.

COMMUNITY AND EXPERT INPUT

In the course of developing its strategic guidance, the committee placed high value on community and expert input and the considerable scientific progress reported in scientific and technical journals.²⁰ In addition to the review of past studies on magnetic fusion energy strategy and research needs, the committee heard from representatives from the European Union, China, Japan, and the Republic of Korea who addressed the committee and described near-term and long-term research plans. The committee conducted visits to the national fusion research facilities at General Atomics and the Princeton Plasma Physics Laboratory and walked through the ITER construction site located beside the Cadarache research center of the French Alternative Energies and Atomic Energy Commission. More than 50 technical white papers were received; more than 2 dozen technical lectures were presented to the committee during seven open meetings (Appendix B); and references to more than 300 technical and scientific papers were cited to illustrate the progress in fusion energy science research.

The committee also benefited from two independent strategic planning activities (Appendix F). The first was a series of community workshops titled “U.S. Magnetic Fusion Research Strategic Directions.”²¹ The goals of the workshops were to discuss, debate, and develop critical technical information required for the development of a strategic plan, including program mission and goals, and to present and discuss opportunities to achieve those goals through the pursuit of various scientific and technical programs. These workshops were highly successful and involved hundreds of researchers across the country. Workshop participants prepared detailed technical reports on nine strategic research program elements, descriptions of various strategic approaches to fusion research planning, and summaries of important working group topics such as the impact of ITER access to U.S. fusion scientists and the requirements for attractive fusion power systems. The second activity supporting magnetic fusion strategic planning was the work of the DOE FESAC Subcommittee on Transformative Enabling Capabilities Toward Fusion Energy. FESAC released the subcommittee’s report in February 2018,²² which identified “the most promising transformative enabling capabilities (TEC) for the U.S. to pursue that could promote efficient advance toward fusion energy, building on burning plasma science and technology.” The report identified several technologies (advanced computer algorithms, high magnetic field and high critical temperature superconductors, advanced materials and manufacturing, novel technologies for tritium fuel cycle control, and fast flowing liquid metals) each with “tremendous opportunity to accelerate fusion science and technology toward power production” and with the potential to transform fusion power systems to become more economically attractive for commercialization.

ASSESSMENTS FROM THE INTERIM REPORT

This final report builds on the committee’s seven assessments of the status and importance of U.S. burning plasma research to the development of fusion power presented in the interim report.²³ These are as follows:

The first two assessments address the importance of burning plasma research to the development of fusion energy science and describe the achievements of the U.S. research program contributing to increased confidence in burning plasma studies to be conducted with the ITER device. The next three assessments describe programmatic shortfalls in the U.S. program that threaten the health of the field

and hamper progress in necessary fusion technology research to improve and fully enable fusion power. The last two assessments from the interim report deserve emphasis because they directly relate to the committee’s strategic guidance.

As explained in Assessment 6, as an ITER partner, the United States benefits from the long-recognized value of international cooperation to combine the scientific and engineering expertise, industrial capacity, and financial resources necessary to create and study burning plasma at the scale of a power plant (i.e., ITER). Because burning plasma research in support of ITER and in preparation for ITER experiments is a primary focus of the international and U.S. research programs, ITER is more than a construction project. ITER plays a central role in today’s U.S. burning plasma research activities, and participation in the ITER project provides formal mechanisms for U.S. scientists to take leading roles in the international effort to develop fusion energy. Additionally, because the vast majority (approximately 80 percent) of U.S. ITER construction funding remains within the U.S. supply chain, participation in ITER has resulted in significant advances in U.S. domestic industrial capabilities and capacities that would not have happened without ITER participation.

A decision by the United States to withdraw from the ITER project as the primary experimental burning plasma component within a balanced long-term strategic plan for fusion energy could isolate U.S. fusion scientists from the international effort and would require the United States to develop a new approach to study a burning plasma. The impact of a decision to withdraw from ITER would be disruptive. Because there is currently no mature burning plasma experiment as an alternative to ITER, the design, construction, and licensing of such an alternative to ITER would require significant development by the U.S. program, as well as a new approach to avoid isolation from the international fusion energy research effort.

The committee’s study in preparation for this final report has reinforced its conclusion that continuation as a partner in the ITER project best serves the nation’s strategic plan for fusion energy. For this reason, the primary guidance within this report assumes continued U.S. participation in ITER and presents a strategy for the demonstration of fusion electricity that benefits from ITER operation and from new developments in technologies that will lower fusion’s development costs. The committee did not find any reasonable or compelling strategy for fusion power development without ITER participation, and no such strategy was presented to the committee that could provide a technical basis for recommended guidance. What the committee does provide, nevertheless, is a generic plan if the United States decides to withdraw from ITER, which has similar goals but requires a larger commitment of resources for longer periods of time.

As explained in Assessment 7, if the United States wishes to maintain scientific and technical leadership in this field, the committee concludes that the United States needs to develop its own long-term strategic plan for fusion energy. This

assessment reinforces the recommendations of the 2009 report²⁴ and echoes the recommendations of congressional leaders and a 2014 Government Accountability Office report.²⁵ After adopting such a plan, the United States can better set research priorities and attract the talented scientists and engineers who will drive research toward commercially viable fusion reactor designs. Indeed, now is the right time to expand the U.S. effort beyond the study of a burning plasma and include the accompanying research to fully enable fusion power. If the United States is to profit from its share of the ITER investment, a strategic research plan directed toward realizing fusion energy in the long term is necessary.

As a result of research progress and the potential for new technologies to improve the economic attractiveness of fusion power and lower the cost of fusion development, the committee’s guidance presents a plan for the United States to benefit from its investment in burning plasma research and take steps toward the development of fusion electricity for the nation’s future energy needs. Four elements important to the committee’s guidance are as follows:

• Continued progress toward the construction and operation of a burning plasma experiment leading to the study of burning plasma,
• Research beyond what is done in a burning plasma experiment to improve and fully enable commercial fusion power,
• Innovation in fusion science and technology targeted to improve the fusion power system as a commercial energy source, and
• A mission for fusion energy research that engages the participation of universities, national laboratories, and industry in the realization of commercial fusion power for the nation.

Today, there is little doubt that fusion energy can be produced in the laboratory. The questions now being asked are different than before and cannot be answered by science alone. Whether fusion can be done in a reliable, economical, and socially acceptable way requires finding inventive solutions to challenges that intersect science, technology, and engineering and combining the talents of plasma scientists and skilled engineers. These remaining challenges are by no means trivial. Fusion research and development would need to be sustained for several more decades, and major new test facilities will need to be carefully designed and constructed. Needless to say, fusion research, like any grand undertaking, will be most successful when guided by a national strategic plan that sets priorities, supports decision-making, and establishes a long-term goal by which to measure progress.

STRUCTURE OF THE FINAL REPORT

The following five chapters describe the committee’s guidance for a strategic plan leading to the production of electricity from a compact fusion pilot plant:

• Chapter 2 describes scientific and technical progress and how this progress has improved confidence that a burning plasma experiment, like ITER, will succeed. Chapter 2 provides three findings about this progress and further developments needed to progress beyond ITER toward fusion electricity.
• Chapter 3 describes the important burning plasma science to be learned from participation in ITER and how the United States can benefit from ITER participation and inform the design of a compact pilot plant. Chapter 3 concludes with three findings: a description of the scientific and technical benefits from ITER, the importance of ITER in the U.S. program, and how advancements in understanding magnetic confinement point to improvements beyond the ITER baseline and with two recommendations for how DOE/FES should conduct both the near-term and long-term ITER research. Chapter 3 also includes two findings describing research needs if the U.S. withdraws from the ITER project and states the committee’s recommendation that the United States should not withdraw. However, even in the scenario without ITER participation, DOE/FES should still initiate a plan leading toward the construction of a compact fusion pilot plant. In the scenario without ITER, an alternate means to study a burning plasma and to engage the international community would be required.
• Chapter 4 describes the interconnected science and technology research within the new national program. It describes research building upon ITER results and reaching the lowest possible capital cost for the compact pilot plant. Chapter 4 concludes with a detailed finding itemizing the technical and scientific support motivating a new national research program leading to the construction of a compact pilot plant. Chapter 4 also concludes with four recommendations to DOE and planning of its new program of accompanying research and technology leading to the compact pilot plant. These include resolving five critical research needs, planning for the construction of new research facilities, and the adoption of a two-phase approach to its plans for the compact pilot plant so that scientific and technical risks can be addressed cost effectively.
• Chapter 5 reviews the foregoing chapters and summarizes the committee’s strategic guidance for U.S. burning plasma research. The committee’s two main recommendations are elaborated. This chapter summarizes program elements, an approximate research timeline, a response to a decision to withdraw from ITER, and budget implications of the committee’s guidance.

• Chapter 6 discusses organizational structure, program management, and other management goals to further strengthen U.S. fusion research with partnerships with related efforts within DOE, with industry, and with the international research community. Chapter 6 concludes with five findings and seven recommendations aimed to guide the implementation of an expanded DOE/FES research program and strengthen community participation in the burning plasma science, materials science, fusion nuclear sciences, and engineering sciences needed to realize an economical pathway to fusion electricity for the nation.

The following chapters contain many technical details of the proposed strategy based on study and deliberation. However, the committee expects its guidance will need further technical development and further input from the U.S. fusion energy science community. Nevertheless, based on the advanced state of understanding the science of magnetic confinement, new developments in superconducting magnets and advanced manufacturing methods, the considerable expert input received by the committee, and the committee’s expertise, this report provides a technically sound pathway that gains experience with a burning plasma at the scale of a power plant and that also starts a national plan for the accompanying research and technology leading to the construction of a compact pilot plant at the lowest possible capital cost and the production of electricity from fusion.

NOTES

8. NRC, 2009, A Review of the DOE Plan for U.S. Fusion Community Participation in the ITER Program, Washington, DC: The National Academies Press, https://doi.org/10.17226/12449, p. 16.

9. European Fusion Development Agreement (EFDA), 2012, Fusion Electricity: A Roadmap to the Realization of Fusion Energy, November, https://www.euro-fusion.org/wpcms/wp-content/uploads/2013/01/JG12.356-web.pdf.

10. Y. Wan, J. Li, Y. Liu, X. Wang, V. Chan, C. Chen, X. Duan, et al., 2017, Overview of the present progress and activities on the CFETR, Nuclear Fusion 57:102009.

11. H. Yamada, R. Kasada, A. Ozaki, R. Sakamoto, Y. Sakamoto, H. Takenaga, T. Tanaka, H. Tanigawa, K. Okano, K. Tobita, O. Kaneko, and K. Ushigusa, 2016, Japanese endeavors to establish technological bases for DEMO, Fusion Engineering and Design 109:1318-1325.

12. NASEM, 2018, Interim Report, p. 4.

13. The Fusion Energy Sciences Advisory Committee (FESAC) is the chartered FACA committee to provide independent advice to the Director of the Office of Science on complex scientific and technological issues that arise in the planning, implementation, and management of the fusion energy sciences program. The FESAC Charter and membership are available at https://science.energy.gov/fes/fesac.

14. DOE, 2017, Project Execution Plan for U.S. ITER Subproject-1, DOE Project No. 14-SC-60, Office of Science, Fusion Energy Sciences, Washington, DC, January.

15. ITER Council, 2018, “22nd ITER Council affirms project progress to achieve First Plasma in 2025,” press release, June 21, https://www.iter.org/doc/www/content/com/Lists/list_items/Attachments/777/2018_06_IC-22.pdf.

16. See current activities of the Board on Physics and Astronomy at http://sites.nationalacademies.org/BPA/BPA_048421.

17. S.O. Dean, 2017, Historical perspective on the United States fusion program, Fusion Science and Technology 47(3):291-299, doi:10.13182/FST05-A708.

18. NRC, 2004, Burning Plasma, p. 152.

19. P. Wouters, G. Serra, J. Furlan, and Ph. Jucker, 2017, Implementation at ITER of the French Order of 7 February 2012, Concerning Basic Nuclear Installations within the European Domestic Agency, Nuclear Fusion 57:100401.

20. Appendixes B through F provide the agendas for committee meetings and site visits, bibliography of past studies consulted, and summary of input received from the fusion research community.

21. See website for community workshops on U.S. Magnetic Fusion Research Strategic Directions at https://sites.google.com/site/usmfrstrategicdirections/home.

22. DOE, 2018, Transformative Enabling Capabilities for Efficient Advance Toward Fusion Energy, report of the U.S. DOE FESAC, Washington, DC, February. https://science.energy.gov/~/media/fes/fesac/pdf/2018/TEC_Report_1Feb20181.pdf.

23. NASEM, 2018, Interim Report.

24. NRC, 2009, Review of the DOE Plan.

25. U.S. Government Accountability Office, 2014, Fusion Energy: Actions Needed to Finalize Cost and Schedule Estimates for U.S. Contributions to an International Experimental Reactor, Report to Congress, GAO-14-499, Washington, DC, June.