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China’s nuclear fusion reactors continue to achieve important milestones in pursuit of controlled and boundless energy production. On December 30, the Experimental Advanced Superconducting Tokamak (EAST) kept plasma at fusing temperatures of 120 million degrees Celsius (216 million degrees Fahrenheit) for an incredible 1,056 seconds, breaking its own record set just seven months before.
Announced by the Institute of Plasma Physics, Chinese Academy of Sciences (ASIPP), this is the longest length of time high-temperature plasma has been confined for. It was also a phenomenal achievement for the reactor itself. Its previous record was 10 times shorter; tests in May saw the reactor maintain 120 million degrees Celsius for 101 seconds.
The reactor has reached higher temperatures before, but for a much shorter time. In May it also saw the creation of plasma at 160 million degrees Celsius for 20 seconds.
Those temperatures are incredible. To give a sense of them, the core of the Sun, where hydrogen fusion takes place, sits at a temperature of 15 million degrees Celsius (27 million degrees Fahrenheit). These reactors handle temperature at least six times hotter.
In fact, the magic number in fusion is 100 million degrees Celsius. That’s what’s needed in reactors on Earth to make fusion happen. While at the core of the Sun, incredible pressures keep the hydrogen confined so temperatures can be lower. Nuclear fusion reactors can’t create those pressures, so they use strong magnetic fields to keep the plasma together and let it fuse into heavier elements. The fusion process releases incredible quantities of energy, and that’s what researchers hope to extract and turn into electricity.
A tokamak is one of the two common designs for nuclear fusion reactors, the other being a stellarator. A tokamak can be imagined as a big empty donut (technically speaking a torus). Plasma of deuterium and tritium (a version of hydrogen with extra neutrons) is injected into the donut and kept there by the magnetic fields. There it is superheated and begins fusing, releasing energy.
That is a very simplified explanation, which doesn’t do justice to the enormous and complex task of achieving these milestones. Every aspect of nuclear fusion in the lab has been an incredible engineering feat and still much more work will need to be carried out before self-sustaining nuclear power plants are a reality.
“ASIPP has a perfect team. We will face up to difficulties no matter how hard it is!” Professor Yuntao Song, Director-General of ASIPP, said in a statement.
The work done at EAST will be instrumental in informing the operation of ITER, the international collaboration funded by the European Union with contributions from China, India, Japan, South Korea, Russia, and the United States. ITER will be a full-size nuclear fusion reactor whose goal is to test technology that will one day be used in commercial facilities.
