What Europe and Japan have just achieved in nuclear fusion is extremely important for the future of energy

The JT-60SA experimental nuclear fusion reactor is an essential stop on the way to ITER (International thermonuclear experimental reactor), a massive fusion reactor being built by an international consortium Led by Europe In Cadarache (France). Like the latter, the JT-60SA is a reactor Tokamak Fusion through magnetic confinement, although not hosted in Europe; He lives in Naka, a small city not far from Tokyo (Japan).

Its construction began in January 2013, but it was not done from scratch; It did so from the JT-60 reactor, a device that became operational in 1985 and that over more than three decades has achieved very important milestones in fusion energy. Assembly of the JT-60SA was completed in early 2020, and the intention of the scientists involved in its development was to begin plasma testing as soon as possible.

Important note: In the commissioning and operation of the JT-60SA reactor, Europe and Japan go hand in hand. It is a joint project that ultimately seeks experiments with the potential to provide extremely valuable knowledge ITER is paying off. This is exactly the importance of the Naka machine. Fortunately, this collaboration has so far met the itinerary that was set on time. This confirms the new achievement reached by European and Japanese technicians.

The first plasma is here

Over the past few months, the JT-60SA experimental reactor has given us many interesting things. The latest of them all, and perhaps also the most important, arrived at the beginning of last August. The engineers working on developing this machine were able to successfully cool the reactor’s magnetic motor. It was not easy because the temperatures that must be reached for the magnets and central solenoid of nuclear fusion reactors to achieve superconductivity are very low.

If we stick to the JT-60SA reactor, the working temperature of the coils is 5.15 K (-268 °C); Central solenoid 17.15 K (-256 °C); Finally, the 18 toroidal field coils and 6 9.15 K (-264 °C) stabilization coils. The next step to be taken was also very important because it required starting the reactor to implement it First plasma test. This crucial test was performed a few days ago by the engineers operating the reactor, and fortunately, it was successful. Over the next few weeks, they will continue to study their results and conduct more tests, but this first experiment went smoothly. Whatever the case, they will announce their final analysis on December 1st.

This achievement opens the door wide for the first phase of experiments using the JT-60SA reactor, which aims to prove that the superconducting magnets responsible for confining plasma at very high temperatures behave stably when supplied with very high current. During this phase the researchers will also perform other fundamental checks, among which we can highlight monitoring the shape of the plasma and analyzing the impurities that accumulate in the reactor core.

On a very large scale, the next phase aims to study the behavior of the plasma, so it will be very important to determine whether the stabilization strategies to be implemented at ITER are suitable or not. When fully operational, the JT-60SA reactor will be able to sustain a deuterium nuclei plasma for 100 seconds with The maximum current is 5.5 mA. The ITER will be larger than the JT-60SA, which will theoretically allow it to reduce energy losses in the reactor core and contribute to plasma stabilization.

The third experimental phase of the Naka fusion reactor will attempt to recreate working conditions as similar as possible to those of ITER in order to accurately predict how the plasma will behave in the experimental reactor in Cadarache (France). This stage is similar to the previous one, but now researchers will monitor very specific parameters that determine the behavior of the plasma, such as, for example, its internal rotation or the effects of particle energy on the stabilization and confinement of the plasma.

The fourth stage of the JT-60SA reactor experiment aims, in general, to find the optimal operating parameters to improve the behavior of the plasma in real time, reduce energy loss and solve the impurity transfer problem with guarantees. Finally, the fifth stage continues Mitigating potential risks Derived from the ITER process. If all goes according to EUROfusion’s plans, low-energy tests using hydrogen and helium in this last experimental reactor will begin in 2028, and high-energy tests in 2032. The JT-60SA reactor will be an extremely valuable ally, without which ITER will certainly be unable to do so. Much more difficult.

Cover Photo: F4E/QST

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