A large Japanese-European experimental nuclear fusion project, “the energy of the stars”, which raises many hopes, was inaugurated this Friday in Japan at a site associated and complementary to the Iter program in France, which is accumulating setbacks and delays.
Installed at the Naka Fusion Institute, about a hundred kilometers northeast of Tokyo, the JT-60SA is currently the largest operational “tokamak” (experimental nuclear fusion reactor) in the world, awaiting completion by its older brother Iter .
This machine “brings us closer to fusion energy, combining high and sustained performance. It is the result of a collaboration between more than 500 scientists and engineers and more than 70 companies in Europe and Japan,” stressed Sam Davis, deputy head of the JT-60SA.
As a result of the 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. And on October 23, it was achieved for the first time. produce plasma. , a very low density gas essential for nuclear fusion.
The JT-60SA “will have to be used to carry out various experiments before Iter is completed,” Masahito Moriyama, Japanese Minister in charge of Science and Technology, recalled on Friday.
Therefore, the lessons learned from this reactor should be valuable for the Iter reactor, which will be about twice the size and have almost five times the plasma volume.
A future “key component of the energy mix”?
The fusion of two light atomic nuclei (hydrogen) to create a heavy one (helium) generates energy, and it is this process that occurs in stars like our Sun.
It differs from fission, a technique currently used in nuclear power plants, which consists of breaking the bonds of heavy atomic nuclei.
Fusion 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, unlike the latter, would be safe, according to scientists.
However, obtaining this energy is only possible by heating the plasma to extremely high temperatures (more than one hundred million degrees Celsius). To prevent this material from cooling and ensure that it remains stable, it must be confined, for example using megamagnets in the case of JT-60SA and Iter.
Above all, for this energy source to be viable it will be necessary to guarantee 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 from nuclear fusion a year ago, and repeated this feat last summer, while improving performance.
Encouraged by these successes, the US government now hopes to begin commercial exploitation of nuclear fusion within the next ten years.
Iter’s pharaonic facility in Cadarache (southern France) is accumulating setbacks causing delays and additional costs, in particular due to defective essential parts. Initially scheduled for 2025, its first plasma production could be postponed for several years.
Source: BFM TV
