Japan commissions test reactor for nuclear fusion research
Published: Friday, Dec 1st 2023, 11:10
Retour au fil d'actualité
The world's largest test facility for a nuclear fusion reactor has officially been in operation in Japan since Friday. The JT-60SA fusion plant in Naka north of Tokyo, a Japanese-European cooperation project, will "bring mankind closer to fusion energy", said deputy project manager Sam Davis at the commissioning ceremony.
It is "the result of a collaboration between more than 500 scientists and engineers and more than 70 companies throughout Europe and Japan".
EU Energy Commissioner Kadri Simson explained that until the international test reactor Iter, which is being built in Cadarache in the south of France, goes into operation, the plant in Japan will be the largest and "most advanced" tokamak-type reactor in the world. Its commissioning is a "milestone in the history of nuclear fusion". Switzerland is also involved in the Iter project.
In nuclear fusion, atomic nuclei are fused together at extremely high temperatures. This releases enormous amounts of energy. Conventional nuclear power plants, on the other hand, generate energy by splitting atomic nuclei.
Smaller than future reactor in France
The fusion plant in Japan is significantly smaller than the Iter test reactor in southern France, which is still under construction. It consists of a donut-shaped container, the tokamak, in which plasma is heated to 200 million degrees Celsius. This is intended to cause hydrogen nuclei to fuse and release energy.
A considerable amount of energy is therefore required to bring about nuclear fusion. Although dozens of experimental reactors have been built since the 1950s, only one facility has so far succeeded in generating more energy than is needed. In December last year, the National Ignition Facility (NIF) in Livermore, California, reported a "net energy gain" during tests. However, the US facility uses a different technology to JT-60SA and Iter.
Controversial technology
According to its supporters, nuclear fusion could become a clean alternative to the combustion of fossil fuels and controversial nuclear fission in the long term. Nuclear fusion has the potential "to become a key component of the energy mix in the second half of this century", explained EU Commissioner Simson.
However, nuclear fusion is also controversial: environmentalists criticize it as inefficient, complex and expensive. As nuclear fusion is still decades away from being ready for the market, renewable energies such as solar energy are the better alternative for the energy transition. In addition, nuclear fusion also produces radioactive waste, albeit to a much lesser extent than nuclear fission.
©Keystone/SDA
French 
English 
German 
Spanish 
Arabic