Nuclear fusion reactor for 30 seconds

Nuclear fusion is the primary function of our sun. Unlike fission, which powers nuclear power plants, fusion has the advantage that it does not produce waste, but has the drawback that requires conditions that are difficult to reproduce outside our star: the confluence of deuterium and tritium nuclei, which “fuse” in helium nuclei, requires a temperature of at least 100 million degrees. Plasma is then formed, a state of matter whose density must be sufficient and permanent – so that other atomic nuclei continually meet and fuse. Theoretically, we then get an inexpensive and inexhaustible power supply.

It is recognized that the experimental power plants that conducted nuclear fusion – under the name tokamak– there since the sixties. But for a long time, each of these experiments was measured in fractions of seconds. In 2019, the experimental South Korean KSTAR reactor (Korea’s superconducting research developed Tokamak) set a new record in 8 seconds. It has grown to 20 seconds in 2020. Now with 30 seconds at a temperature of at least 100 million degrees Celsius, confirmed That the problem is increasingly fading from the hands of physicists for these engineers: How do we support this activity to become a sustainable source of energy?

longer periods Affected elsewhere in the worldbut not in a high confinement mode as here: an essential initial step for a potential reactor capable of operating continuously.

The difficulty lies not only in heating the plasma, but in confining it so that it does not come into contact with the walls of the reactor. Magnetic fields play this role, but their control remains, even today, a major challenge. ITER reactor (International Thermonuclear Experimental Reactor), which is an international cooperation under construction In southern France, which should theoretically create its first plasma in 2027, it will follow in the footsteps of KSTAR: trying to achieve a balance between temperature and magnetic fields, a balance that ensures the stability of the process and, as a result, the production of electricity.

The new findings, which were detailed by South Korean researchers at article Published by the magazine on September 7. temper nature, they suggest that their approach, which consists in obtaining a lower plasma density, makes it possible to maintain the reaction for a longer time. The fact remains that we are only talking about 30 seconds, and that the ultimate goal, if it is to be reached, It always lies in the future for decadesAnd not years…

Photo: South Korea’s KSTAR Project.