https://www.nature.com/articles/d41586-021-02459-w
NEWS
09 September 2021
Correction 10 September 2021
China prepares to test thorium-fuelled nuclear reactor
If China’s experimental reactor is a success it could lead to commercialization and help the nation meet its climate goals.
Smriti Mallapaty
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A panoramic view of phase I, II and III units of the Tianwan Nuclear Power Plant in China.
China has more than 50 conventional nuclear power plants, such as this, but the experimental thorium reactor in Wuwei will be a first.Credit: Costfoto/Barcroft Media/Getty
Scientists are excited about an experimental nuclear reactor using thorium as fuel, which is about to begin tests in China. Although this radioactive element has been trialled in reactors before, experts say that China is the first to have a shot at commercializing the technology.
The reactor is unusual in that it has molten salts circulating inside it instead of water. It has the potential to produce nuclear energy that is relatively safe and cheap, while also generating a much smaller amount of very long-lived radioactive waste than conventional reactors.
Construction of the experimental thorium reactor in Wuwei, on the outskirts of the Gobi Desert, was due to be completed by the end of August — with trial runs scheduled for this month, according to the government of Gansu province.
Thorium is a weakly radioactive, silvery metal found naturally in rocks, and currently has little industrial use. It is a waste product of the growing rare-earth mining industry in China, and is therefore an attractive alternative to imported uranium, say researchers.
Powerful potential
“Thorium is much more plentiful than uranium and so it would be a very useful technology to have in 50 or 100 years’ time,” when uranium reserves start to run low, says Lyndon Edwards, a nuclear engineer at the Australian Nuclear Science and Technology Organisation in Sydney. But the technology will take many decades to realize, so we need to start now, he adds.
China launched its molten-salt reactor programme in 2011, investing some 3 billion yuan (US$500 million), according to Ritsuo Yoshioka, former president of the International Thorium Molten-Salt Forum in Oiso, Japan, who has worked closely with Chinese researchers.
Operated by the Shanghai Institute of Applied Physics (SINAP), the Wuwei reactor is designed to produce just 2 megawatts of thermal energy, which is only enough to power up to 1,000 homes. But if the experiments are a success, China hopes to build a 373-megawatt reactor by 2030, which could power hundreds of thousands of homes.
These reactors are among the “perfect technologies” for helping China to achieve its goal of zero carbon emissions by around 2050, says energy modeller Jiang Kejun at the Energy Research Institute of the National Development and Reform Commission in Beijing.
The naturally occurring isotope thorium-232 cannot undergo fission, but when irradiated in a reactor, it absorbs neutrons to form uranium-233, which is a fissile material that generates heat.
Thorium has been tested as a fuel in other types of nuclear reactor in countries including the United States, Germany and the United Kingdom, and is part of a nuclear programme in India. But it has so far not proved cost effective because it is more expensive to extract than uranium and, unlike some naturally occurring isotopes of uranium, needs to be converted into a fissile material.
Some researchers support thorium as a fuel because they say its waste products have less chance of being weaponized than do those of uranium, but others have argued that risks still exist.
MOLTEN-SALT REACTOR. Graphic showing how a molten-salt nuclear reactor works.
Source: US Department of Energy/International Atomic Energy Agency
Blast from the past