Tokyo

Off line: refurbishment of Japan's JT-60 fusion reactor could take up to ten years.

The Japan Atomic Energy Research Institute (JAERI) plans to overhaul its JT-60 tokamak fusion reactor at a cost of ¥35 billion (US$325 million). The task will take between five and ten years.

The reactor will be shut down in autumn of next year so that its magnetic coils can be replaced with superconducting ones. According to Masato Nakamura, director of the fusion development office at the Science and Technology Agency, of which JAERI is part, the goal is to increase the reactor's normal operation time from 15 to 100 seconds.

But what looks to be a boost for fusion might actually indicate that budgets for such research are growing tight in Japan, some observers say. The tokamak's closure will save a large part of its ¥10 billion annual operating costs — so the reconstruction could save the government money if it takes long enough. A completion date for the project has not been announced. And the Science and Technology Agency's budget request for 2001 includes only ¥2.3 billion for the reconstruction.

Fusion researchers are far from enthusiastic at the prospect of the reactor being shut down for up to ten years. “In terms of technology, replacing the coils should take three or four years and we hope this is what happens,” says Shinzaburo Matsuda, director of JAERI's Naka Fusion Research Establishment.

Nakamura defends the plan, arguing that reconstructing the reactor will make it more economical and stable.

Both Nakamura and Matsuda insist that the plan will not affect Japan's commitment to the proposed International Thermonuclear Experimental Reactor (ITER) project. “We believe that siting ITER in Japan is essential for the project's success,” says Nakamura.

According to Nakamura, savings from the suspended operation of JT-60 will make it easier for Japan to increase its contribution to the ITER project.

Matsuda adds that, in its long term plan for fusion research, the Japanese Atomic Energy Comission defined an experimental reactor like ITER as the “core reactor” while designating “other tokamak devices” for advanced research to support the core machine during both the experimental and demonstration phases.

But Steve Dean of Fusion Power Associates, which lobbies for fusion research in Washington, expressed surprise at the plan. Although Japanese officials had said they could do both, outsiders had assumed that Japan would decide either to refurbish JT-60 or to proceed with ITER, he said.