Executive Summary

Fusion energy offers the prospect of 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 construction phase of the ITER fusion reactor (formerly, the International Thermonuclear Experimental Reactor) 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 the development of fusion electricity for the nation’s future energy needs.

This report of the Committee on a Strategic Plan for U.S. Burning Plasma Research describes a strategic plan for fusion research to guide implementation of the committee’s two main recommendations:

• First, the United States should remain an ITER partner as the most cost-effective way to gain experience with a burning plasma at the scale of a power plant.
• Second, the United States should start a national program of accompanying research and technology leading to the construction of a compact pilot plant that produces electricity from fusion at the lowest possible capital cost.

ITER is a burning plasma experiment and the critical next step in the development of fusion energy. It is a large and ambitious project that integrates multiple

advanced technologies and combines the scientific and engineering expertise, industrial capacity, and financial resources of many nations. As a partner, the United States receives full benefit from the technology developed for ITER while providing only a fraction of the financial resources. Methods to control the plasma and extract the electricity-producing heat will be tested and developed. U.S. industry is building major systems for ITER and thereby gaining expertise in fusion engineering science and building industrial capabilities.

Although the United States provides only part of the cost of ITER, if the United States is to profit from its share of the ITER investment, the nation’s strategic plan for fusion should combine its ITER experience with the additional science and engineering research needed to realize reliable and economical fusion electricity. Without this additional research, the United States risks being overtaken as other nations advance the science and technology required to deliver a new and important source of energy.

Recent advances motivate a new national research program leading to the construction of a compact fusion pilot plant. Significant progress in predicting and creating the high-pressure plasma required for such a reactor has been made. Opportunities to develop technologies for fusion, such as high-temperature superconducting magnets and advanced materials, now make a compact device possible. A focus on a compact device will accelerate the fusion development path, making it affordable and attractive for industrial participation. Finally, by starting now, a national research program aimed toward a compact pilot plant and critical science and technology research can be ready in time to use the knowledge learned from ITER operation to demonstrate electricity production by mid-century.

The committee envisions a U.S. pilot plant producing power similar to that expected in ITER but in a device much smaller in size and cost and employing design improvements that would allow net electricity production. This compact burning plasma fusion pilot plant would be a pre-commercial research facility. In addition to the production of fusion electricity, it would ultimately be capable of uninterrupted operation for weeks and produce tritium, the heavy isotope of hydrogen in fusion fuel. As a pilot plant, its purpose will be learning, but the knowledge obtained would be sufficient to design the first commercial fusion power systems.

A new national focus on developing a compact pilot plant in the long term will help set priorities for the near- and mid-term fusion program. Research needs to show how to increase the fusion power density beyond that obtainable in ITER. Uninterrupted operation should be demonstrated while researchers learn how to handle reliably the high levels of heat escaping from the plasma. New program elements should begin immediately to develop the materials and technologies needed to extract the heat and recirculate tritium and to promote the industrial development of very-high-field superconducting magnets for fusion. Finally, technology

innovations should be encouraged and developed to simplify maintenance and lower construction cost.

The committee recognizes that there are risks involved in developing a compact fusion pilot plant. Resolving these risks will necessitate the design and operation of new facilities. One of the greatest risks is the control of a continuous high-pressure compact plasma, which will require the design and construction of a new intermediate-scale research facility in the United States, or a significant upgrade to an existing facility, to establish its feasibility. Another significant risk is the qualification of the materials and components that surround the plasma and are exposed to fusion irradiation. The committee’s proposed strategic plan also includes other recommendations aimed at improving and reducing the cost of fusion as a source of electricity through the development of promising innovations in burning plasma science and fusion engineering science.

The committee expects that the implementation of its recommendations, including both continued participation in ITER and the start of a national research program for a compact pilot plant, will require additional funding, rising to nearly $200 million beyond the recently enacted annual funding levels. This funding would need be sustained for several decades. Although the funding remains level, the research portfolio evolves over time, and existing research facilities are phased out as new ones are implemented.

The committee was also tasked to recommend strategic guidance if the United States decides to withdraw from the ITER project. This withdrawal would significantly disrupt the national research effort, isolate U.S. researchers from the international effort, and eliminate the benefit of sharing the cost of producing burning plasma at the power plant scale. Nevertheless, if the United States decides to withdraw from the ITER project, the committee recommends that the United States continue research toward the construction of a compact fusion pilot plant. However, without ITER participation, U.S. progress will necessitate a significantly larger commitment of resources for a longer time. Without ITER, the United States would need to design, license, and construct an alternative means to gain experience in creating and controlling an energy-producing burning plasma. The scale of research facilities within the United States would become larger, more ambitious, and more expensive. As a result, producing net electricity from fusion in the United States would be delayed.