Washington

Friends and foes of nuclear power in the United States are battling over a proposal to spend up to $1.1 billion on an 'intrinsically safe' fission-reactor design.

Supporters of the plan, led by Senator Pete Domenici (Republican, New Mexico), have allocated $30 million for it in the Senate version of next year's funding bill for the Department of Energy. But the House version makes no such provision, and the project's immediate fate will be determined at a conference between the two sides in the next few weeks.

The proposed reactor at the Idaho National Environmental and Engineering Laboratory near Idaho Falls would burn pellets of uranium fuel just 0.5 millimetres in diameter. Some five billion of the pellets would either be fused into billiard-ball-sized graphite spheres or encased in a honeycomb-like graphite structure. The system would be cooled by helium circulating at nearly 1,000 °C, which could directly drive turbogenerators. Advocates of the design claim that the helium could also be used to generate hydrogen for use as fuel.

“This new reactor will also be inherently safe,” says Jim Lake, associate director of nuclear energy at the Idaho lab. In the event of coolant loss, the core will reach 15,000 °C but will not melt down, he says, because of graphite's high heat tolerance.

Critics counter that the design has other safety problems. “Graphite can't melt, but it can catch fire,” says David Lochbaum, a nuclear engineer with the Union of Concerned Scientists, a non-profit environmental group.

Chris Paine of the Natural Resources Defense Council, another environmental group, doubts that generating large quantities of flammable hydrogen at a nuclear reactor will ever be safe or economic. “The capital costs of generating hydrogen from a nuclear reactor are absurdly high,” he says. “It makes no sense.”

Andy Kadak, a nuclear engineer at the Massachusetts Institute of Technology, says that a graphite fire is unlikely, and that hydrogen could be generated in buildings a safe distance from the reactor at off-peak times.

An energy bill that would recommend spending $1.1 billion on the project over the next five years is being held up by disputes over unrelated issues, such as energy regulation.