In August 2021, China announced the completion of its first experimental thorium-based nuclear reactor. Built in the middle of the Gobi Desert in the country’s north, the reactor over the next few years will undergo testing. If the experiment proves successful, Beijing plans to construct another reactor potentially capable of generating electricity for more than 100 000 homes.
China is not alone in its intentions to reap thorium's unique properties. In the past, India, Japan, the United Kingdom, the United States of America and other countries have demonstrated enthusiasm for research into the possible application of thorium in nuclear power. The appeal of this metal is its potential to be a more abundant and efficient substitute for uranium, the dominant nuclear fuel.
However, using thorium for energy production is not without challenges, and these are discussed in a new IAEA publication Near-Term and Promising Long-Term Options for the Deployment of Thorium-Based Nuclear Energy. Comprehensively summarising the results of a four-year IAEA coordinated research project focused on the possibilities of developing thorium-based nuclear energy, the report examines the benefits and the challenges of using thorium as a fuel and analyses its application in different types of reactors — from the most commonly deployed water-cooled reactors to molten-salt reactors.
“Many countries consider thorium as both a viable and very attractive option for generating power and meeting their growing energy needs,” said Kailash Agarwal, a Nuclear Fuel Cycle Facilities Specialist at the IAEA and one of the authors of the report. “Our research project helped share valuable knowledge and experience among national laboratories and research institutions in the use of thorium, culminating in this publication.”
Thorium is a silvery, slightly radioactive metal commonly found in igneous rocks and heavy mineral sands. It was named after Thor, the god of thunder in Norse mythology. It is three to four times more abundant in nature than uranium but historically has found little use in industry or power generation. This is partly because thorium in itself is not a nuclear fuel, but it can be used to create one. Thorium-232, the only naturally occurring isotope of thorium, is a fissionable material but not a fissile one, meaning that it needs high-energy neutrons to undergo fission — the splitting of atomic nuclei which releases energy that is used for electricity generation. However, when irradiated, thorium-232 undergoes a series of nuclear reactions, eventually forming uranium-233, a fissile material that can be burned up as fuel in nuclear reactors.
