China’s Experimental Advanced Superconducting Tokamak (EAST) fusion reactor on 28 May achieved another world record by maintaining a plasma temperature at 120 million decrees Celsius for 101 seconds and at 160 million Celsius for 20 seconds, a major step toward the test run of the fusion reactor. EAST is located at the Hefei Institutes of Physical Science of the Chinese Academy of Science (ASIPP) in Hefei. It is one of three major domestic tokamaks now in operation in China. China’s HL-2M tokamak fusion reactor at CNNC’s Southwestern Institute of Physics (SWIP) in Chengdu, Sichuan was commissioned in December 2020 – an upgrade the previous model, the HL-2A. The third is J-TEXT at the Huazhong University of Science and Technology (HUST).

The latest achievement breaks the record set by South Korea’s KSTAR (Korea Superconducting Tokamak Advanced Research) which in December 2020 maintained 100 million C for 20 seconds.

The researchers at EAST have also surpassed their colleagues at the HL-2M which late last year kept a 150 million degree hot plasma stable for a period of 10 seconds.

According to Li Miao, director of the physics department of the Southern University of Science and Technology in Shenzhen, this is a milestone in reaching the goal of keeping the temperature at a stable level for a long time. "The breakthrough is significant progress, and the ultimate goal should be keeping the temperature at a stable level for a long time," he told the Global Times, adding that the next milestone might be to maintain the stability for a week or more. However, Lin cautioned that as the technology is still in the experimental stage and still needs at least 30 years to mature. "It's more like a future technology that's critical for China's green development push."

The results from EAST will feed into the International Thermonuclear Experimental Reactor (ITER) facility under construction in France that is being jointly constructed by the EU, Russia, China, India, Japan, South Korea and the USA. At ITER, which is aiming for first plasma in 2025, researchers are seeking to hold a plasma heated to a temperature of 150 million Kelvin for 400 seconds. 

EAST has been operating since 2006 and during this time has set several records for the duration of confinement of an increasingly hot plasma. It is one of the few thermonuclear installations in the world with a fully superconducting magnetic system based on niobium-titanium conductors. 

As well as supporting ITER, China’s fusion facilities all pave the way for the China Fusion Engineering Testing Reactor (CFETR), the preliminary conceptual design of which was finished in 2015 and engineering design started in 2017. CFETR is intended for steady-state operation, as well as tritium self-sustainment. In phase one it should have 200MW fusion power and in phase two it should have power of 1GW. It aims to bridge the fusion experiments between ITER and DEMO – the proposed nuclear fusion power station expected to build upon ITER. DEMO is seen as the next step towards a "first of a kind" commercial station. CFETR aims to provide DEMO validation.

Image: China’s Experimental Advanced Superconducting Tokamak (EAST) fusion reactor