Edited by Clive Cookson
Supporters of reactors based on thorium say the chemical element is safer and more powerful than uranium
A relatively safe and clean form of nuclear energy, first developed and tested in the US in the late 1960s but neglected by the commercial nuclear industry, may be about to gain a new lease of life.
Supporters of reactors based on thorium, rather than uranium, are trying to re-awaken interest in this forgotten chemical element. Thorium should be safer than uranium because thorium reactors would shut down without any human intervention. Nor would they need mechanical cooling systems to remove excess heat, eliminating the possibility of accidents such as Fukushima.
“Not all nuclear power is equal. Thorium is inherently safer,” says Baroness Bryony Worthington, the Labour peer and campaigner for climate change. “It offers very low-cost, sustainable, safe forms of nuclear power.”
Baroness Worthington is patron of the Weinberg Foundation, a new organisation set up to campaign for the development of thorium technology. “It’s a fuel that no one has heard of, that everyone needs to hear of,” she says.
The organisation is named after the nuclear physicist Alvin Weinberg, who pioneered thorium energy in the US in the 1960s. Bob Cywinski, a physicist at the University of Huddersfield, believes thorium may have been ignored at that time because it would not have provided the plutonium useful for nuclear weapons.
“It’s an unfortunate fact that civil nuclear power has always had a link to the military. And thorium does not produce plutonium,” he says.
Cywinski believes it is time to look again at the technology. “Thorium has an energy density far greater than any other element in the periodic table: one tonne of thorium is equivalent to 200 tonnes of uranium. It’s 100 per cent useable; it doesn’t need processing or enriching. It’s an enormous untapped resource,” he says.
Thorium is more abundant than uranium, with enough thorium deposits to power the world for many thousands of years, and it generates much less radioactive waste when burned in reactors. It can even be mixed with waste from conventional reactors to burn it up.
The main obstacle is that the nuclear industry has a huge reactor and fuel infrastructure based on uranium and plutonium. An enormous additional investment would be needed to shift to thorium.
But Baroness Worthington believes we should be planning to start developing the technology now on a modest scale to prove the concept, and then scale up.
She suggests that one of the sites allocated for new nuclear reactors in the UK could be set aside for an innovative thorium project.