tokyo

The International Thermonuclear Experimental Reactor (ITER), a proposed US$10 billion project to build a next-generation fusion facility, faces significant scaling down after its council last week adopted new design parameters for a smaller, cheaper version.

At a meeting in Tokyo, council members of the ITER partners — the United States, Europe, Japan and Russia — approved proposals by its working group to reduce costs by modifying some of its technical objectives.

The working group, set up in February to explore less expensive designs for the reactor, proposed in May that the cost could be cut by up to half by reducing the radius of the doughnut-shaped confinement vessel from 8 metres to 6 metres (see Nature 393, 406; 1998), and by reducing its output from 1.5 GW to 0.7 GW.

Although the new design would alleviate budgetary constraints, the reactor's ignition — required to generate a self-sustaining thermonuclear burn — is likely to be lost. But officials from the Japanese Atomic Energy Research Institute (JAERI), which put forward the plans for the scaled-down version, say that ignition may not be essential for carrying out successful nuclear fusion.

“Although some of ITER's aims have been relaxed, the proposed changes are not viewed as a compromise,” says Hiroshi Kishimoto, an executive director.

Japan is the most likely candidate to host the site, as it is expected to put up the largest share of the cost for the international project.

At a meeting earlier this month, Japan's Atomic Energy Council decided to present ITER's design team with detailed data on Japan's regional characteristics, such as information on earthquake prevalence and maps of coastal areas adequate for placing fusion reactors.

Although it declined to look into sites, the council created a subcommittee on fusion energy development that will discuss Japan's future effort in nuclear-fusion research and the possibility of collaboration with industry. But the government says it will not make any decision about ITER's location for two years because of the nation's current economic crisis.