Washington, D.C. (5 December 1996) -- The multibillion-dollar International Thermonuclear Experimental Reactor (ITER) -- billed as the world's best hope for proving that fusion can be a reliable and efficient source of abundant power -- probably won't work, according to a new theory discussed in a 6 December Science news report by James Glanz.
If construction is completed as planned before 2010, ITER will be a building-sized, donut-shaped device called a "tokamak" that is threaded with spiraling magnetic fields. The fields would cage superhot ions long enough for them to fuse and, designers hope, become the world's first controlled, self-sustaining fusion burn, releasing huge amounts of power. The $10 billion megaproject is sponsored by the United States, Russia, Europe and Japan.
Recently, however, fusion researchers have been buzzing with a new theory about plasma turbulence that lets them know with a greater degree of certainty how much heat loss occurs during such a process. Science has learned that the theory's two creators -- William Dorland and Michael Kotschenreuther of the University of Texas at Austin -- have warned ITER scientists that, according to their calculations, ITER "wouldn't work, and by a substantial margin."
A computer model based on their theory shows that turbulence within ITER could shorten the energy confinement to the point where, far from generating the 1.5 billion watts in fusion power that ITER's official documents project, it may give back no more than a few times the energy used to heat the plasma in the first place -- much too little to ignite a fusion burn. In a sidebar, ITER scientists admit that their own official estimates are flawed.
Copies of this news report are available. Please contact Karissa Sparks by phone at 202/326-6414, fax at 202/789-0455, or email at ksparks@aaas.org. You can also see an embargoed copy of the news report in the Bench Notes section of EurekAlert! (http://www.eurekalert.org/).