On Tuesday, December 13, 2022, the United States announced a historic scientific breakthrough in this field, which could within decades revolutionize energy production on Earth by providing abundant clean energy.
“For the first time, an experiment has succeeded in producing an amount of energy greater than that used by lasers causing the reaction,” Lawrence Livermore National Laboratory in California announced in a statement. The achievement will go“ into the history books,” Energy Secretary Jennifer Granholm said at a news conference.
Nuclear fission, nuclear fusion ? How it works…
Nuclear fission consists of projecting a neutron onto an unstable heavy atom (uranium 235 or plutonium 239). This neutron absorbs the atom, causing it to split into two lighter atoms: this produces energy, radioactive radiation and two or three neutrons. These new neutrons will then be able in turn to cause fission: the operation is repeated ad infinitum. Today, fission is used in nuclear power plants to produce electricity.
Conversely, nuclear fusion brings together two hydrogen atoms (deuterium and tritium) at temperatures of several million degrees. When these atoms fuse, the new nucleus created is in an unstable state: it ejects a helium atom and a neutron with a lot of energy.
This reaction, found at the heart of stars, is reproduced inside a tokamak: an experimental reactor that confines a fusion plasma.
In stars, as in fusion machines, plasmas constitute a medium in which hydrogen atoms can fuse and generate energy. The electrically charged particles that make up the plasma can be confined and controlled by powerful magnetic fields generated by superconducting magnets.
In order to maintain the superconducting state of these magnets, Absolut System uses cryogenic technologies by cooling them to temperatures below -250°C (~20K).
Thanks to this, the magnets can generate the very intense magnetic fields necessary for the confinement and stabilization of the plasma.
“Superconducting magnets could not, with current superconductor technologies, function without cryogenics and thus provide the magnetic fields necessary for plasma confinement in nuclear fusion experiments. It is fascinating to imagine these magnets maintained at temperatures so close to absolute zero while in proximity to a material, the plasma, which is levitating at several million degrees. The challenge of developing such systems is colossal and Absolut System is proud to participate in the design and supply of the cooling systems! “ Matthieu Dalban, Absolut System Project Engineer
It will still take time to implement, but nuclear fusion remains the hope for abundant energy and a better environmental future for our planet.