China designs nuclear reactor without cooling water

A molten salt nuclear reactor that uses thorium instead of uranium could be built in the desert and provide electricity for 100,000 people.

A research group working for the Chinese government has released a design for a commercial reactor, which promises to be the world's first reactor without cooling water, allowing the system to be built in areas where water is not needed. remote deserts to provide electricity to more densely populated areas.

The molten salt reactor works on liquid thorium instead of uranium , which is safer than a traditional reactor, releasing less radiation into the environment. Construction of the first commercial reactor will be completed by 2030. China is planning to build several reactors in the deserts and plains of the central and western regions. It is also considering building reactors in a number of countries under the agreement under the Belt and Road Initiative because unlike uranium, thorium cannot be used to make nuclear weapons.

Molten salt nuclear reactors can be built in water-scarce deserts. (Photo: Reuters).

"Small-scale reactors have big advantages in terms of efficiency, flexibility and economy. They can play an important role in the transition to clean energy in the future. Small-scale reactions will be widely deployed in the next few years , " said Professor Yan Rui and colleagues at the Shanghai Institute of Applied Physics, in a study published in the Chinese journal Nuclear Engineering this week. prior to. "The molten salt reactor has the advantages of being multi-purpose, small in size and highly flexible, and easy to design. In recent years, the potential of small-scale molten salt reactors is growing. attracted the attention of the international community".

An important impetus for the molten salt reactor program came from President Xi Jinping's announcement last year that China would be carbon neutral by 2060, according to the scientists involved in the project. According to the official plan, the reactor in the remote western part of the country will provide clean and stable electricity to the more densely populated eastern region, combined with wind and solar power plants.

The technology could also provide new power sources for China's warships as well as aircraft carriers and submarines. The idea of ​​a reactor operating on molten salt instead of coils of solid fuel dates back to the 1940s. In the following decade, the United States began an experimental program to build bombers powered by magnetism. this technology.

During the 1960s, the United States built a facility to test the technology's ability to produce electricity, while other countries such as France, the Soviet Union, and Japan conducted similar programs. The idea is intriguing because the liquid fuel acts as a self-cooling agent, eliminating the need for water, and thorium's lower radioactivity reduces the risk of nuclear proliferation.

The initial projects above all failed because they could not solve problems such as pipes cracking easily under the erosion effect of radioactive molten salt. But researchers have learned a lot from the experiments. In recent times, researchers in this field have received steady support from the Chinese government. In 2011, Beijing approved a plan to build a prototype thorium molten salt reactor (TMSR) in Wuwei, a desert city in Gansu province.

Many research groups across the country have also been mobilized to solve technical problems that have caused previous attempts to fail, such as developing alloys that can withstand radiation from thorium salts at temperatures close to 1,000 degrees Celsius. The project is behind schedule, partly due to Covid-19, construction of the TMSR will be completed next month, and testing of the device could begin as early as September 2021.

Although the prototype can only produce 2 megawatts (MW), if successful, this will be the first time the idea has turned into reality. The commercial reactor designed by Yan and colleagues can provide up to 100 MW, less than a uranium reactor but enough to power a residential area that includes 100,000 residents. Although the power plant needs other equipment such as steam turbines, the reactor itself is only 3 meters high and 2.5 meters wide, about the size of a bathroom.

The reactor works through letting thorium pass through the furnace, participate in a nuclear chain reaction and transfer heat to an external steam generator before returning to the reactor to start a new cycle. The technology is safer than traditional nuclear reactors because in the event of an accident, molten salt will be dumped into an underground storage tank. With a high melting point, the molten salt will rapidly cool and harden without the direct release of solid and liquid waste, thereby preventing radioactive dispersion into the environment.

China has some of the largest reserves of thorium in the world. It is a weakly radioactive silver-like metal. Some scientists calculate the country has enough thorium reserves to meet energy needs for at least 20,000 years. In contrast, the country's uranium reserves are the lowest among nuclear weapons states. Although China is set to put seven or eight new nuclear power plants into operation in the next few years, authorities are still concerned that a fuel shortage could affect their energy security.