he Lawrence Livermore National Laboratory LLNL, in California, was able to put its name in history by generating too much energy in December 2022 in its reactor at the National Ignition Center (NIF) to cause a fusion reaction, the same reaction that occurs in stars and promises to be a clean, safe and reliable source. Almost depleted in the coming decades. Since then, NIF scientists have not remained idle: they have worked to recreate, and even improve, the performance of their experiment. Last July they achieved a new milestone: generating twice as much energy.
This is what they say in five studies (which can be consulted). here, here, here, here And here) was published in the journal Physical Review Letters in which they give an account of their (successful) experiments, as in the first half of last year they accumulated several failed experiments that led to concerns that this achievement was in part a happy experiment by a coincidence of factors.
The researchers noted in a statement, “This achievement is the culmination of more than five decades of research and demonstrates that laboratory-controlled fusion energy based on basic physical principles is possible.” launch. Because scientists have been trying for decades to control the energy of stars, but only their reactor has shown that humanity is capable. Although there are still many steps to take in order for this source to power our microwaves and refrigerators.
Fission vs. fusion
Current nuclear power plants rely on fission reactions, where atoms break apart to release energy and smaller particles. However, nuclear fusion works in the opposite way: In this reaction, hydrogen molecules clump together and collide with each other at enormous temperatures and pressures inside, creating a heavier element, helium. This method is safer because it does not produce radioactive waste as fission does; Moreover, the raw materials from which they are made are very simple; On the other hand, fusion reactions extinguish on their own without harm. The problem is the part about recreating it, controlling it and extracting the energy here, on Earth, without the massive gravity and high temperatures of the Sun: that part is a huge challenge.
Currently, the only reactor that has been able to generate more energy than necessary to catalyze the reaction is NIF. It did this thanks to inertial confinement in an experiment that involved 192 lasers directed at a small gold capsule the size of a peppercorn, filled with deuterium and tritium (forms of hydrogen). Thanks to the enormous pressure exerted on this “ball” (to which the rays were directed with a margin of error less than the thickness of a hair), a reaction was generated, which lasted millionths of a second, though long enough as it were to prove it. Once again, the system works and the tremendous energy that “powers” the stars can be replicated here.
Specifically, studies reveal that this reactor generated net profit for the first time on December 5, 2022, although three other experiments conducted in the following months were also successful, including one that managed to generate 1.9 times the power it originally fired. . Three pieces of evidence that the achievement achieved was not the result of chance.
Technology in diapers
Although these experiments prove that the results that left the world speechless “were not a matter of a single moment,” he points out. NewScientist Richard Towne, one of the NIF officials, says there is still a long way to go before these reactions become, in fact, a vital source of energy on a daily basis. Because each shot requires approximately a month of preparation, and calibration of each laser millimetrically; Not only that, but it is also necessary for the deuterium and tritium sphere to be perfect – if not, the interactions will be much weaker.
Furthermore, to maintain a constant reaction over time, one ball after another must be fired continuously, i.e. about 10,000 balls per day. On the other hand, although the reaction generates more energy than is required to start, this is actually theoretical, since starting the laser would require the expenditure of 500,000 million watts, or a thousand times more energy than the energy produced by the US National Power Grid. . At any time.
However, Towne is optimistic, and maintains that if the laser is improved, the interactions can be improved: “A bigger hammer always helps,” he points out to the scientific journal. If the technology was more advanced, I think we could achieve profits of close to 10%.
However, the NIF was never built to be a commercial reactor prototype nor was it optimized to increase the throughput of the reactions, only to prove that this method was viable to achieve (and study). In fact, its main mission is to provide important information to the US nuclear weapons program, exposing nuclear bombs to radiation that could occur in the event of a nuclear war.
Efforts of other countries
But the United States is not alone in the race to get energy from the stars. Other countries such as Japan, South Korea and China are investigating this matter. And so is Europe, which with its accession to the European Union (JET) has achieved some interesting milestones (although it will soon be closed, despite voices calling for continued experiments with this reactor). In addition, the International Thermonuclear Experimental Reactor (ITER) is currently being jointly developed, a huge project involving the European Union, Japan, the United States, South Korea, India, Russia and China.
In 2006, they all signed an agreement to create the largest reactor prototype ever built in Cadarache (France). It differs from NIF, above all, in its way of recreating the pressure and temperature conditions of stars in our laboratories: while the North American commitment relies on an inertial confinement system, ITER uses enormous and powerful magnets – magnetic confinement. To control the burning plasma in a huge donut-shaped container in which the required power source is generated.
Although the project is currently only accumulating delays, the idea is to improve the profit generated by the NIF by up to tenfold and extend it over time. It is estimated that in 2025 ITER will begin its first tests with plasma, which is the main and most important stage. Three years later, low-energy tests using hydrogen and helium will begin, and in 2032, high-energy tests. In 2035, deuterium and tritium tests will be launched, which will complete the process carried out by ITER. If all goes well, the project will be succeeded by another experimental reactor, the Pilot Reactor, which should prove its economic feasibility and serve as a prototype for a commercial reactor. The first commercial fusion reactor is expected to emerge from this massive prototype. But this, for now, is just a promise.
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