In early December 2023, Japanese authorities officially opened the largest tokamak-type thermonuclear reactor on the planet, the JT-60SA. This is an improved version of the Torus-60 (JT-60) project, which has undergone modernization, the implementation of which has been taking place in the country for more than 50 years.
The new version of the reactor, weighing 370 tons, was built as a result of Tokyo’s cooperation with the European Union in the energy sector.
Delving into history, it is worth noting that the development of tokamaks was initially carried out by Soviet researchers and scientists. In simple terms, tokamaks are toroidal reactors that are the leading contenders for commercially viable fusion power plants. This type of reactor includes a large donut-shaped chamber that is surrounded by magnetic coils. During operation, the plasma of hydrogen isotopes is compressed using a powerful magnetic field until it reaches temperatures and pressures comparable to the interior of the Sun.
Since 1970, the Torus-60 (JT-60) project has been implemented in Japan. And the JT-60SA tokamak serves as the newest and largest iteration of this program. Initially, the reactor was repeatedly improved and changes were made to its operation as new technologies appeared in the world.
In 2013, it was decided to completely disassemble it and reassemble it. Construction and installation work was completed in 2020, but a year later a major short circuit occurred, necessitating costly and time-consuming repairs that took another two years.
The grand opening and launch of the JT-60SA tokamak after repairs was held on December 1 of this year. At the same time, the researchers note that the improved reactor is still far from being a practical energy generator, but it will be actively used in Japan in research activities, when testing various materials and procedures that will be an integral part of commercial fusion power plants of the future.