The Shanghai Institute of Applied Physics (SINAP) of the Chinese Academy of Sciences will begin construction of a demonstration 10-MW thorium molten salt reactor in the new year. The pilot reactor project was put into operation in 2021, which predetermined the fate of the direction – there will be thorium reactors! The project has shown its success and will be repeated at a new level.
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The creation of a network of thorium reactors will allow China and a number of other countries to get rid of their dependence on uranium fuel. There is more than enough thorium on Earth for hundreds or more years of burning in nuclear reactors to produce energy, which cannot be said about uranium, the reserves of which are unlikely to last more than 500 years. In addition, thorium is found in excess in waste from the extraction of rare earth elements. China is a leader in the processing of such ores and has already accumulated an unimaginable amount of waste, the processing of which is waiting in the wings.
The difficulty with thorium is that it does not undergo nuclear fission and must be converted into a suitable isotope of uranium. To do this, thorium-232 is loaded into a molten salt breeder reactor. Thorium fluoride melts in the reactor core, and the thorium-232 isotope becomes thorium-233 during irradiation. The half-life of thorium-233 is about 20 minutes, after which half of this substance decays to the isotope protactinium-233. The latter has a longer half-life of 27.4 days, during which it decays into uranium-233, a suitable fuel for fission reactions. During the decay to uranium-233, protactinium is removed from the reactor and returned to it in the form of uranium fuel. The Chinese pilot project has shown its efficiency, although the economic feasibility of the process is still in question.
Let us remind you that the pilot project was implemented in the Gobi Desert. A 2 MW molten salt reactor with an electrical power of 1 MW was built there. The SINAP institute responsible for the project assessed the project as promising and planned to build a 60-MW reactor there in 2025 with an electrical power of 10 MW (the rest is heat, which can also be used). A more powerful molten salt thorium reactor should be commissioned in 2030. If successful, it will be scaled up another order of magnitude – up to the generation of 100 MW of electrical energy.
Before the start of thorium reactors in China, the only facility of this kind created in the world was the reactor at the Oak Ridge National Laboratory in the USA (ORNL). It was stopped in 1969. Since then, no one has created thorium reactors. Today, interest has arisen in them not only in China. Many countries are starting to design molten salt reactors as a safer alternative to classic nuclear power plants. There is some concern that radioactive fuel must remain outside the reactor for some time until it “reaches condition”, and this is a threat of uncontrolled spread. Therefore, there are projects in which protactinium does not leave the reactor and forms uranium in the core, which cannot be reached.
Be that as it may, thorium reactors are now being designed in the countries of the European Union, the USA, Japan and India. China has shown that this path can be followed and intends to continue to remain ahead of the rest. While others are drawing plans, he confidently builds.