Nature reports that the Joint European Torus (JET) fusion reactor near Oxford in the United Kingdom has produced the highest sustained energy level ever from atomic fusion. The “Tokamak” reactor produced 59 megajoules of energy during a five-second fusion pulse on December 21, 2021, more than double what it achieved in 1997.
“These landmark results bring us one big step closer to tackling one of our greatest scientific and engineering challenges,” said Ian Chapman, president of the Culham Center for Fusion Energy (CCFE).
The JET reactor is the high-end experimental instrument of the EU-funded European Fusion Program (EUROfusion). It is possible to describe it as a kind of power source. It draws attention with its system, which is similar to the sun’s heat dissipation process.
JET is primarily driving future experiments of the much larger ITER reactor built in France to begin fusion testing in 2025; It was designed to help scientists prove their modeling was correct. “JET really did deliver on what was predicted. The same modeling now shows that ITER will work,” said fusion physicist Josefine Proll, unrelated to JET, in a conversation with Nature.
CCFE plasma scientist Fernanda Rimini said the experiment pushed the reactor to “absolute maximum”. JET used a mixture of deuterium (aka heavy water) and tritium, the same fuel mix to power the ITER. The researchers also modified the Tokamak’s inner wall to reduce tritium waste.
The JET reached a Q of 0.33, which means it produces about a third of the energy expended. The highest Q value ever achieved by the U.S. Department of Energy’s National Ignition Facility is 0.7, but this figure was only achieved in a time of 4 billionths of a second.
The aim of ITER is defined as achieving a Q factor target of 10 or higher while generating 500 MW of power for long 400 to 600 second pulses. ITER will not generate net energy in the form of electricity, but will pave the way for machines that can generate it in the future.
But before that happens, researchers need to solve a few tough problems. In principle, the heat generated in the exhaust zone of the ITER has to be dissolved, since it will be proportionally much larger than the JET reactor. Still, the success of this experiment allowed the team to gather a wealth of information that could be analyzed over the next few years.
“If we can keep the fusion going for five seconds, we can do it in five minutes and five hours later when we scale up our operations on future machines,” says Tony Donne, program manager for EUROfusion…
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