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Fall 2003 Vol. 3 No. 3

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Burning Plasma

Bringing the Power of the Sun to Earth

Scientists have been trying for six decades to produce energy the same way the sun does: by converting hydrogen into helium in a process called nuclear fusion. Unlike nuclear fission, in which nuclei of atoms are split to create power or a massive explosion, fusion -- as the name implies -- fuses, or brings together, atomic nuclei. Fusion could provide an inexhaustible supply of energy, lessening our dependence on fossil fuels. And while it leaves behind some low-level radioactive waste, fusion eliminates the risk of a catastrophic accident that is possible in a traditional nuclear reactor.

For fusion to occur, atomic nuclei need to be heated to an extremely high temperature -- on the sun, it is 10 million to 15 million degrees Celsius. To reach such incredible temperatures here on Earth, scientists have devised experiments using lasers or powerful magnets to create a state of matter that is neither a solid, liquid, nor gas, but a very hot plasma -- a mixture of fast-moving nuclei and electrons.

But to produce sustainable fusion, scientists need to create a "burning" plasma, where fusion itself provides much of the heat required. The most promising experiment of this type is an international effort called the International Thermonuclear Experimental Reactor (ITER). Fusion researchers sponsored by the U.S. Department of Energy are scientifically and technically ready to -- and should -- undertake a burning plasma experiment, preferably by participating in ITER, says a new report from the National Research Council.

ITER began as a joint U.S.-Soviet program in 1988, but the United States withdrew 10 years later amid cost concerns. Now scientists from Russia, Canada, Japan, and the European Union are preparing to build this facility, which is "the most mature design and both sound and carefully planned," the report says. It calls ITER "the best opportunity for the United States to engage in a burning plasma experiment."

In the past year, the Bush administration has announced its willingness to rejoin ITER, and negotiations of the U.S. role in the construction of the $5 billion project are under way. Regardless of whether those negotiations succeed, the U.S. fusion program should be strengthened and diversified, the report says.

DOE officials should map out a multiyear strategic plan that includes a balanced portfolio of theoretical and experimental research that could be conducted in parallel with ITER, the report adds. If the negotiations to participate in this project fail, the United States should pursue a burning plasma experiment with other international partners.   -- Patrice Pages & Bill Kearney

Burning Plasma: Bringing a Star to Earth. Burning Plasma Assessment Committee, Board on Physics and Astronomy, Division on Engineering and Physical Sciences (2003, approx. 185 pp.; ISBN 0-309-09082-2; available from the National Academies Press, tel. 1-800-624-6242; $39.00 plus $4.50 shipping for single copies).

The committee was co-chaired by John F. Ahearne, director of the Ethics Program at the Sigma Xi Center in Research Triangle Park, N.C., and Raymond J. Fonck, nuclear engineering and engineering physics professor at the University of Wisconsin, Madison. The study was funded by the U.S. Department of Energy.

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Copyright 2003 by the National Academy of Sciences