Japan inaugurates an experimental nuclear fusion reactor, partner of the French Iter program

The JT-60SA project is the result of agreements between Japan and the European Union. It uses magnetic technology to confine the plasma needed for nuclear fusion.

A vast Japanese-European experimental nuclear fusion project, called “star energy”, was inaugurated in Japan on Friday December 1st. The kick-off was given on a partner and complementary site of the Iter program in France, which is accumulating setbacks and delays. Installed in the Naka Fusion Institute, about a hundred kilometers northeast of Tokyo, the JT-60SA is currently the largest tokamak (experimental nuclear fusion reactor) operational in the world.

The result of agreements between Japan and the European Union signed in 2007, the construction of this tokamak 15.5 meters high and 13.5 meters in diameter lasted from 2013 to 2020. The JT-60SA is intended to address essential physics questions to better prepare for the operation of Iter, and in the longer term commercial applications of nuclear fusion. “Japan and Europe are positioning themselves as world leaders in fusion research” by magnetic confinement, welcomed the European Commissioner for Energy, Kadri Simson.

The fusion of light atomic nuclei is the energetic process at work in stars, like our Sun. It is considered a very promising future energy source, because it does not generate greenhouse gases, produces less radioactive waste than current nuclear power plants, and is safe according to scientists.

Nuclear fusion with megamagnets

At the end of October, this tokamak succeeded for the first time in producing plasma, a very low density gas essential for nuclear fusion. This is only possible by heating the plasma to extremely high temperatures – more than a hundred million degrees Celsius. To prevent this material from cooling and remaining stable, it must be isolated, for example using mega-magnets in the case of JT-60SA and Iter. Above all, for this energy source to be viable, it will be necessary to ensure that the energy produced exceeds that used to cause the reaction.

Using another plasma confinement technology, using an ultra-powerful laser, the United States was the first to achieve a net energy gain with nuclear fusion a year ago, and reissued this feat last summer by improving performance. Encouraged by these successes, the American government now hopes to launch the commercial exploitation of nuclear fusion within the next ten years.

The French Iter site is accumulating setbacks, leading to delays and additional costs, notably due to defective essential parts. Originally planned for 2025, its first plasma production could be postponed for several years.