China is putting the finishing touches on the world’s first thorium nuclear reactor

China is pushing the development of an experimental reactor that would be the first of its kind in the world but could prove key to the pursuit of cleaner and safer nuclear energy. According to local news, the Chinese government plans to complete the construction of a prototype molten salt nuclear reactor in the desert city of Wuwei in the coming months, followed by a number of larger plants in similar environments.

With their ability to generate electricity while producing very minimal CO2 emissions, nuclear reactors have a clear advantage when it comes to sustainable energy production. However, there are very compelling reasons why the technology is not widespread around the world, many of which stem from reliance on uranium and plutonium for fuel.

Not only is uranium expensive and rare, it can also be used to build nuclear weapons. These reactors also generate radioactive waste that needs to be safely stored and carry the very real risk of a catastrophic meltdown like the one observed in Fukushima in 2011.

Since the 1940s, scientists have been researching an alternative known as molten salt reactors, which promises to be a far safer route. Instead of uranium and plutonium, these reactors use the widely used silvery metal thorium, which cannot easily be used to make bombs. In addition, these reactors would be operated in a manner that does not present the same hazards as conventional reactors.

Instead of solid fuel rods, thorium is dissolved in a molten salt that flows through the reactor at a high temperature. In this form, the liquid salt acts as a coolant and no high pressure water cooling systems are required, and if the fuel is exposed to air in an accident, it cools quickly and solidifies. Compared to a conventional nuclear reactor, which can quickly cover large areas with radioactive material, this significantly limits the potential contamination of the environment.

Despite his promise, the advancement of the technology behind the molten salt reactors has been slow. Experiments were carried out in the US in the 1960s and 1970s, then in Asia and Europe. Recently, in the Netherlands, we saw a research group doing experiments aimed at turning the technology into an industrial-scale energy source.

More recently, China has led the indictment. In 2011, the government approved plans for a thorium molten salt reactor in the desert city of Wuwei, Gansu Province, and commissioned its scientists to develop the technology for its operation. Now, as the South China Morning Post reports, construction of the two-megawatt reactor prototype should be completed next month and the first tests could begin as early as September.

If these plans are implemented, the plant would be the world’s first operational thorium smelting salt reactor. Government scientists hope to use it as a stepping stone to the development of larger thorium molten salt reactors, up to 100 MW, planned for several other desert locations, each capable of supplying 100,000 residents with electricity. Construction of the first commercial reactor is expected to be completed by 2030.

The plans are big, but the fine details remain open, particularly regarding the technical obstacles that have plagued the technology in the past. A major problem that molten salt reactors have to contend with is corrosion, with the radioactive molten salt tending to corrode piping or other components.

Another concerns the processes that drive energy production. Conventional nuclear reactors are capable of fissioning uranium atoms in a way that causes a chain reaction and continuous energy production, while thorium does not contain enough fissile material to do this on its own. This means that it has to be mixed with uranium or other materials anyway that will help trigger the necessary reactions.

This means that a thorium nuclear reactor has never been proven on a commercial scale and many have doubts that it ever will be. In any case, China’s scientists have spearheaded research and development in this area since the project started a decade ago, so maybe they are finally ready to show their hand.

Source: South China Morning Mail