World's largest experimental reactor put into operation in Japan
In nuclear fusion, atomic nuclei are not split, but fused. The JT-60SA experimental reactor, a Japanese-European collaboration, has now been officially inaugurated in Japan.
The world's largest experimental nuclear fusion reactor was officially inaugurated in Japan at the beginning of December 2023. The JT-60SA plant in Naka, north of Tokyo, is a Japanese-European cooperation project and the result of collaboration between more than 500 experts from research and engineering and more than 70 companies. The project will "bring mankind closer to fusion energy", said deputy project manager Sam Davis at the commissioning ceremony, according to the AFP news agency. The aim of the JT-60SA reactor is to explore the feasibility of fusion as a safe, large-scale and carbon-free net energy source.
Nuclear fusion is seen as a virtually inexhaustible, emission-free source of energy without the risk of catastrophic accidents and without the need for final disposal of long-lived radioactive waste. The idea of imitating on Earth what the sun has been doing for five billion years has been fuelling research since the 1950s. Nuclear fusion differs from nuclear fission in that two atomic nuclei are fused together instead of splitting one nucleus into two. Inside stars such as our sun, the atomic nuclei of hydrogen fuse to form helium nuclei, releasing vast amounts of energy. However, all terrestrial attempts to date have fallen far short of efficiently generating energy using this principle.
EU Energy Commissioner Kadri Simson stated, according to AFP, that until the international test reactor ITER, which is currently under construction in Cadarache in the south of France, the plant in Japan is the largest and "most advanced" tokamak-type reactor in the world. Its commissioning is a "milestone in the history of nuclear fusion." The reactor consists of a donut-shaped container, the tokamak, in which a hydrogen plasma is heated to 200 million degrees Celsius.
Technology still has many hurdles to overcome
So far, only one facility has succeeded in generating more energy than is needed to ignite the plasma. In December last year, the National Ignition Facility (NIF) in Livermore, California, reported a "net energy gain" during trials. However, the US facility uses a different technology to the new Japanese reactor and ITER - so-called inertial confinement fusion. There, almost 200 lasers are used to transfer energy to a pea-sized gold cylinder containing a frozen pellet of the hydrogen isotopes deuterium and tritium. However, nuclear fusion could only be maintained for fractions of a second - it would take hours to generate electricity.
Although critics say that expectations are overestimated and environmentalists describe nuclear fusion as inefficient, complex and expensive, governments and investors around the world are pouring a lot of money into research into the technology. A growing number of start-ups have raised billions in private investment. German politicians and Research Minister Bettina Stark-Watzinger have also pledged additional money for fusion research in recent months.
Spectrum of Science
We are a partner of Spektrum der Wissenschaft and want to make well-founded information more accessible to you. Follow Spektrum der Wissenschaft if you like the articles.
[[small:]]
Cover picture: © dpa / picture alliance (detail) View of the tokamak container of the experimental nuclear fusion reactor JT-60SA in Naka north of Tokyo.
Experts from science and research report on the latest findings in their fields – competent, authentic and comprehensible.
From the latest iPhone to the return of 80s fashion. The editorial team will help you make sense of it all.
Show all