Still at the experimental stage, nuclear fusion gives us hope of being able to produce low-carbon energy in large quantities and on an almost continuous basis. It would generate very little waste, which would also be considerably less radioactive.
For the same quantity of material, nuclear fusion would make it possible to produce 4 million times more energy than fossil fuels: oil, gas and coal.
Representing a real technological challenge, this process requires the confinement of heat at a temperature of 150 million degrees. The reactors have to prevent the walls from melting while maintaining fusion for as long as possible.
Two methods are used to achieve the fusion of atoms: inertial confinement and magnetic confinement.
With inertial confinement, the nuclear fusion is triggered by focusing high-power laser beams onto a fuel capsule, which contains a mixture of deuterium and tritium.
Heated to very high temperatures, these two isotopes of hydrogen atoms then collide and fuse into heavier helium atoms, producing a colossal volume of energy.
Today, there are only two places in the world where experiments are being conducted with this type of fusion, one of which is based in France: the Megajoule Laser (Laser Mégajoule – LMJ) near Bordeaux.
The method of magnetic confinement transforms the deuterium and tritium atoms into plasma, causing them to fuse under the effect of a magnetic field. Experimental reactors are able to reproduce this type of nuclear fusion. These are tokamaks, whose ring-shaped core enables the hydrogen gas to be transformed into plasma, under the influence of extreme temperature and pressure.
The magnetic coils around the wall are used to control the plasma particles.
One of the flagship projects in fusion energy is ITER, also located in France. The tokamak has to be capable of containing a temperature of 150 million degrees. The objective of this project is to open the way for the harnessing, production and industrial commercialization of hydrogen fusion.
In China, the EAST tokamak nuclear fusion reactor broke a record in January 2022, by maintaining a temperature of 70 million degrees (equivalent to four times the temperature at the core of the Sun) for over 17 minutes.
The Chinese reactor was also successful in containing 120 million degrees for 101 seconds and 160 million degrees for 20 seconds.
Even if nuclear fusion reactors are promising and have key role to play in our energy future, they are not expected to be in industrial operation before 2050.
Find out more about fusion in this explainer video: