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Arthur T Knackerbracket has processed the following story:
The UK’s 40-year-old fusion reactor achieved a world record for energy output in its final runs before being shut down for good, scientists have announced.
The Joint European Torus (JET) in Oxfordshire began operating in 1983. When running, it was temporarily the hottest point in the solar system, reaching 150 million°C.
The reactor’s previous record was a reaction lasting for 5 seconds in 2021, producing 59 megajoules of heat energy. But in its final tests in late 2023, it surpassed this by sustaining a reaction for 5.2 seconds while also reaching 69 megajoules of output, using just 0.2 milligrams of fuel.
[...] JET forged together atoms of deuterium and tritium – two stable isotopes of hydrogen – in plasma to create helium, while also releasing a vast amount of energy. This is the same reaction that powers our sun. It was a type of fusion reactor known as a tokamak, which contains plasma in a donut shape using rings of electromagnets.
Scientists ran the last experiments with deuterium-tritium fuel at JET in October last year and other experiments continued until December. But the machine has now been shut down for good and it is being decommissioned over the next 16 years.
“It’s great that it’s gone out with a little flourish,” says Matthews. “It’s got a noble history. It’s served its time and they’re going to squeeze a bit more information out of it during its decommissioning period as well. So it’s not something to be sad about; it’s something to be celebrated.”
A larger and more modern replacement for JET, the International Thermonuclear Experimental Reactor (ITER) in France, is nearing completion and its first experiments are due to start in 2025.
[...] Another reactor using the same design, the Korea Superconducting Tokamak Advanced Research (KSTAR) device, recently managed to sustain a reaction for 30 seconds at temperatures in excess of 100 million°C.
(Score: 4, Informative) by Rosco P. Coltrane on Monday February 12 2024, @11:38AM (2 children)
69 MJ is the same energy as half a gallon of gasoline. The whole site probably goes through that in 5 seconds too just to keep the lights on.
In other words, while it was probably a great technical success, it's nowhere near unity.
(Score: 4, Interesting) by VLM on Monday February 12 2024, @12:58PM (1 child)
Yeah that Q value is relative solely to heating current. Its a arc welding transformer, pretty much, where the heater coils have many turns and the donut is a single shorted turn. IIRC the heating coils run around "forty KW" max.
You'll notice the tokamak people VERY carefully avoid reporting the highest Q ever was at JET IIRC and was well under 1 whereas the laser-boys have been running above 1 for "some time". Of course the secret squirrel bomb people have been running WAY over a Q value of 1 for some decades now, although the instantaneous peak would be an engineering challenge to contain LOL.
(Score: 1) by khallow on Monday February 12 2024, @04:27PM
Keep in mind that there's huge power inefficiency in the lasers that aren't being reported in that Q value. They presently run well under Q=1 too. Still these values are nice in that if they were to greatly reduce the inefficiencies in the ignition/containment systems, they'd be running close or even above Q=1.