The Chinese Academy of Sciences (CAS) has initiated a research and development programme that will investigate using thorium as a fuel in next-generation nuclear power plants. The programme, which aims to be complete by 2030, will involve building a research complex that will include a prototype reactor. Its goal is for China to become a world leader in thorium-based nuclear power generation, allowing the country to own relevant intellectual property and to export its technology worldwide.

China currently obtains about 1.8% of its electricity needs from nuclear power. This is done via second- and third-generation reactors that use uranium as a fissile fuel. Thorium, on the other hand, cannot on its own sustain a chain reaction whereby neutrons released by thorium fission go on to split another thorium nucleus. However, if bathed in an external supply of neutrons, a thorium-232 nucleus can capture a neutron and transmute into uranium-233, which is fissile.

China is currently building a prototype of a thorium–uranium molten salt reactor (MSR), which is one of six international designs for “fourth-generation” nuclear power plants that would be rolled out in the next 20 – 30 years (Physics World October 2010 pp30–35). The MSR is a “thermal” reactor that uses a moderator to slow neutrons down enough to produce fission, with a molten salt such as uranium fluoride used as a coolant. As the thorium nuclear fuel is dissolved into the molten salt coolant, there is no need to use fuel rods or pellets.

“Developing this kind of nuclear power is very important,” says Zhang Huanqiao, a nuclear physicist at the China Institute of Atomic Energy in Beijing. The country has already fired up a prototype “fast-neutron” reactor that can create more fissile material than it consumes (Physics World September 2010 p9) and Zhang believes that if its thorium programme succeeds, within the next 10–15 years the country will be in a position to choose which approach better serves its needs. “In my opinion, we will be able to make a further evaluation on practical and economic grounds,” he says.