Three years ago, the world’s first thorium molten salt nuclear reactor was built in China. Its thermal power was 2 MW. It did not produce electricity. The experiment was successful, which created the basis for the construction in China of the world’s first nuclear power plant using molten thorium salts. Construction of the nuclear power plant and reactor with a thermal capacity of 60 MW will start in 2025. It will be able to generate 10 MW of electrical power, which will be the first such solution in the world.
Image Source: Chinase Academy of Sciences
The first experimental thorium molten salt reactor was built in the USA about 60 years ago. The solution was interesting, but difficult to operate due to the high corrosion of pipes for transporting molten salt. The United States found this solution unprofitable and soon dismantled the reactor. But the beneficial aspects of molten salt reactors have not gone away either.
Fuel is supplied to molten salt reactors in a mixture with a coolant, which is the melts themselves. Such a reactor will not be able to explode during an emergency shutdown like a water reactor. The salt will simply cool down without a significant release of radioactive material, even if there is a breakthrough in the primary circuit. Until now, the mass production of such reactors was stopped by the lack of materials resistant to oxidation at high temperatures. By building and operating a 2-MW reactor in the Gobi Desert (about 120 km northwest of Wuwei, Gansu Province), China has proven that a breakthrough is possible in this area.
Some revolutionary technologies have been tested in practice, including high-temperature alloys that can withstand high temperatures, radiation and chemical corrosion. The small reactor received operating approval from China’s Nuclear Safety Administration in June last year and achieved a critical (sustained) nuclear chain reaction in October.
A new and more powerful thorium reactor with a thermal power of 60 MW and an electrical power of 10 MW will be built near the first reactor on a site smaller than a football field. The molten fuel after passing through the reactor core will heat the second circuit, also with molten salt. The second circuit will drive the turbine using carbon dioxide.
Completion of construction of the facility and its commissioning is expected in 2029. For China, the use of thorium as the main component of the fuel will be of no small importance (uranium or other radioactive materials will still have to be added there) – its reserves in the country will be enough for 20 thousand years of operation of nuclear power plants using molten salts, while China has its own uranium for everything is missing.
In the USA, by the way, they are also trying to revive that ancient project at a new level. This is the work of Bill Gates’ company TerraPower, which is building a reactor using molten sodium salts.