Transmutex and Copenhagen Atomics are among companies working on a nuclear reactor that uses the thorium fuel cycle. "You get thorium from rare earth refining, but it's considered a nuisance material," says John Kutsch, executive director of the Thorium Energy Alliance, who notes that thorium is "easier to handle than uranium, we burn it in a pure cycle, we have much less waste and you can't make a bomb out of it."