The United States announced Tuesday, December 13 a historic scientific breakthrough in the field of nuclear fusion, which could within a few decades revolutionize the production of energy on Earth by providing clean energy in abundance.
For decades, researchers around the world have sought to develop nuclear fusion, which, according to its defenders, could allow humanity to break its dependence on fossil fuels, responsible for global warming.
A discovery “in the history books”?
An experiment carried out last week “produced more energy from the fusion than the energy of the lasers used” to provoke the reaction, explained the Lawrence Livermore National Laboratory (LLNL), located in California and which depends on the American Department of Energy.
This success will be found “in the history books”, said Energy Minister Jennifer Granholm. The announcement, which had already been leaked to the press for a few days, provoked the enthusiasm of the scientific community throughout the world.
Lasers ultrapuissants
Currently, nuclear power plants use fission, which works by splitting the nucleus of a heavy atom, releasing energy. Nuclear fusion, on the contrary, causes the fusion of two light nuclei, to form a heavier one.
This reaction is what powers the stars, including our Sun. Thanks to the extreme heat and pressure conditions that prevail there, the hydrogen atoms fuse to form helium, producing an immense amount of energy in the process.
On Earth, this process can be achieved using ultra-powerful lasers. At the National Ignition Facility (NIF), which depends on the Californian laboratory, no less than 192 lasers are pointed at a target as small as a thimble, where the light hydrogen atoms to be fused are placed. The scientists thus produced about 3.15 megajoules of energy, originally delivering 2.05 megajoules via the lasers, according to the statement.
Decades to complete
Such a result finally provides proof of a physical principle imagined decades ago. Fusion has many advantages over fission: it carries no risk of nuclear accident and produces less radioactive waste. Above all, compared to coal or gas power plants, it does not generate any greenhouse gases.
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However, there is still a long way to go before this solution becomes viable on an industrial and commercial scale. Probably ” decades “, said Kim Budil, the director of the LLNL, on Tuesday. The challenges are technological, the experience must in particular be able to be repeated multiple times per minute, she explained.
Other nuclear fusion projects are in development, in particular the international Iter project, currently under construction in France. Instead of lasers, the so-called magnetic confinement technique will be used: the hydrogen atoms will be heated in a huge reactor, where they will be confined using the magnetic field of magnets.