A historic scientific breakthrough achieved by an American laboratory

The US has made history in the field of nuclear fusion. A scientific breakthrough announced Tuesday could revolutionize energy production on Earth within decades.

For decades, researchers around the world have tried to develop nuclear fusion, which, according to its proponents, could allow humanity to end its dependence on fossil fuels, which are responsible for global warming.

A historic success

Last week’s experiment marked the first time that lasers were able to produce more energy than they used to cause a reaction, the Lawrence Livermore National Laboratory (LLNL) in California announced in a press release. US Department of Energy. Energy Minister Jennifer Granholm stated at a press conference that this success will be found in the “history books”.

The announcement, leaked to the press for several days, has caused the excitement of the entire world scientific community.

At least 192 lasers pointed at a small target

Currently, nuclear power plants use fission, which works by breaking apart the nucleus of a heavy atom to release energy. Nuclear fusion, on the other hand, is the fusion of two lighter nuclei into a heavier one. This reaction powers the stars, including our Sun. Due to the extreme heat and pressure conditions prevailing there, hydrogen atoms fuse together to form helium, releasing large amounts of energy in the process. On Earth, this process can be achieved using ultra-powerful lasers.

The National Ignition Facility (NIF), based out of a California laboratory, is the world’s largest sports stadium-sized laser system. At around 1 a.m. on December 5, at least 192 lasers were aimed at a small thimble-like target made of diamond and containing a small capsule containing hydrogen isotopes (deuterium and tritium).

The lasers created temperatures of about 150 million degrees, or 10 times the temperature of the Sun, causing the hydrogen atoms to fuse together. The reaction takes only a fraction of a second.

The solution is not yet complete

According to the statement, the scientists thus produced about 3.15 megajoules of energy, compared to 2.05 megajoules initially delivered by lasers. However, powering the lasers required 300 megajoules of power drawn from the mains, which still made the operation a total loss. But according to scientists, eventually it will be possible to overcome this problem.

“Our calculations show that with a large-scale laser system it is possible to achieve a yield of several hundred megajoules,” said Kim Budil, director of the Lawrence Livermore National Laboratory. “But we are still far from it. It will take another “decades” (but less than five) to implement this solution on an industrial and commercial scale, he said.

What possible improvements?

Many technological improvements are still required: not only to increase the net energy gain produced, but also to allow the experiment to be repeated several times per minute. However, it is absolutely necessary to reduce greenhouse gas emissions as much as possible today to limit global warming, all climate experts insist. Nevertheless, such a result finally provides proof of a physical principle that was imagined decades ago.

Fusion has many advantages over fission: it does not carry the risk of a nuclear accident and produces less radioactive waste. First of all, it does not produce any greenhouse gases compared to coal or gas power plants.

“Fusion is very important for humanity. »

Other nuclear fusion projects are under development, notably the international ITER project currently under construction in France. Instead of lasers, a method called magnetic confinement will be used: hydrogen atoms will be heated in a giant reactor, where they will be confined using the magnetic field of magnets.

Experts stressed that further research is needed for these two techniques, lasers and magnetic caps. “What we want is to maximize the potential pathways to success, so we want to keep trying these different approaches to see what works,” NIF physicist Tammy Ma said Tuesday. “Fusion is very important for humanity. »

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