‘It’s an efficient machine to destroy nuclear waste’: nuclear future powered by thorium beckons

At COP28 over 20 countries pledged to triple the world’s nuclear energy capacity by 2050 in another step towards net zero. For many, this was a controversial declaration: the devastating consequences of nuclear accidents are well-documented and the fission process generates worrying quantities of long-lived radioactive waste with the potential for use in chemical weapons.

But, according to developers behind new thorium reactor technologies, the nuclear of the future is very different from this historical picture. ‘You get thorium from rare earth refining, but it’s considered a nuisance material,’ says John Kutsch, executive director of the Thorium Energy Alliance in the US. ‘It should be the civilian nuclear fuel – it’s 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.’

Conventional nuclear reactors use enriched uranium-235, the fissile minor isotope that makes up just 0.7% of natural uranium reserves on Earth. The major uranium-238 isotope is non-fissionable and significant pre-reactor processing is required to raise the percentage of uranium-235 to around 5%. Within the reactor core, these unstable nuclei fission spontaneously to release heat and neutrons, the latter then bombarding neighbouring nuclei and inducing further fission, sustaining the nuclear chain reaction.