The United States on Tuesday announced a historic scientific breakthrough in nuclear fusion that could revolutionize energy production on Earth within decades.
For decades, researchers around the world have sought to develop nuclear fusion, which, according to its defenders, would allow humanity to break its dependence on fossil fuels, which are responsible for global warming.
An experiment last week succeeded for the first time in producing more energy than the lasers used to cause the reaction, the Lawrence Livermore National Laboratory (LLNL) in California announced in a press release. US Department of Energy.
Energy Minister Jennifer Granholm announced at a press conference that the victory would go down “in the history books.”
The announcement, which had already been leaked in the press for a few days, sparked excitement in the scientific community around the world.
Currently, nuclear power plants use fission, which works by splitting the nucleus of a heavy atom to release energy. Nuclear fusion, in contrast, is 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 there, hydrogen atoms combine to form helium, producing immense amounts of energy in the process.
150 million degrees
On Earth, this process can be achieved using high-powered lasers.
The National Ignition Facility (NIF), based at the California lab, is the largest laser system in the world, the size of a sports stadium.
At 1 a.m. on December 5, no fewer than 192 lasers were aimed at a target as small as a finger, which contained a small capsule made of diamond and containing isotopes of hydrogen (deuterium and tritium).
The photons produced temperatures of about 150 million degrees, ten times the temperature of the Sun, causing hydrogen atoms to fuse together. The reaction takes only a fraction of a second.
The scientists thus produced about 3.15 megajoules of energy, compared to 2.05 megajoules initially delivered via lasers, the report said.
However, operating the lasers required 300 megajoules of energy taken from the electrical grid — still a loss of overall functionality. But according to scientists, it will eventually be possible to overcome this problem.
“Our calculations suggest that with a large-scale laser system, an output of several hundred megajoules can be achieved”Kim Puddle, director of the Lawrence Livermore National Laboratory, explained. “But we’re still a long way from that.”
Decades to achieve
He said it would take another “decades” (but less than five) to make this solution viable on an industrial and commercial scale.
Many technical improvements are still needed: not only to increase the net energy gain produced, but also to allow the experiment to be repeated many times per minute.
However, all climatologists insist that it is necessary to reduce greenhouse gas emissions as much as possible today in order to control global warming.
After all, such a result finally provides proof of a physical principle that was envisioned decades ago.
Fusion has several advantages over fission: it carries no risk of nuclear accident and produces less radioactive waste. Best of all, it produces no greenhouse gases, compared to coal or gas-fired power plants.
Other nuclear fusion projects are under development, notably the international ITER project, currently under construction in France.
Instead of lasers, a so-called magnetic confinement technique will be used: hydrogen atoms will be heated in a large reactor, where they will be confined using the magnetic field of magnets.
Experts stressed that more research is needed for these two techniques — lasers and magnetic confinement.
“What we want to do is maximize the potential paths to success, so we want to continue these different approaches to see what works.” NIF physicist Tommy Ma said Tuesday. “Connectivity is very important to humanity.”
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