China’s ‘artificial sun’ galaxies away from solving Earth’s energy needs, scientist says

Chinese scientists announced this week that a nuclear fusion reactor in the southeast of the country had achieved a temperature exceeding 100 million degrees Celsius, more than six times those found at the centre of the sun.

But despite the achievements at the Experimental Advanced Superconducting Tokamak (EAST) reactor in Hefei, capital of Anhui province, a scientist said it might still be some time before China is able to tap the energy produced by the fusion process.

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In a commentary published on Thursday by state news agency Xinhua, Zhang Tiankan poured cold water on Monday’s celebrations, saying that achieving the 100 million degree mark was just a milestone and that scientists still had a long way to go.

One of the biggest hurdles to overcome was working out a way to constrain reactions within a restricted space for an extended period, he said.

Another was achieving a sufficiently high plasma density. Only when that was high enough and the plasma temperature exceeded 100 million degrees could a sizeable number of particles with sufficient kinetic energy overcome the repulsion between the nuclei, allowing nuclear fusion reactions to take place, Zhang said.

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The scientists in Hefei said that the EAST reactor, dubbed “China’s artificial sun”, had reached a plasma temperature of more than 100 million degrees, with a discharge pulse of more than 100 seconds.

But Zhang said that to achieve sustained fusion energy, scientists would need to raise the temperature to “hundreds of millions of degrees” and lengthen the pulse to “thousands of seconds”.

More research was also needed to enhance the controllability of the reaction and realise the goal of creating energy using the same process that powers the sun.

Fusion power has the potential to solve the world’s energy problems as it creates massive amounts with only a small impact on the environment.

EAST has so far managed to achieve an electrical output of 10 million watts, equivalent to the energy needed to power 200,000 light bulbs.

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“EAST is like an oven, but to achieve temperatures high enough for nuclear fusion, you need to either make the oven hotter or slow the heat radiation,” said Wan Baonian, director of the Institute of Plasma Physics at the Chinese Academy of Sciences, which runs the reactor.

“It is harder to achieve such temperatures at EAST as it’s small compared with its peers,” he said. “[By comparison] the ITER will in the future be able to achieve temperatures of 200 million degrees.”

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He was referring to the International Thermonuclear Experimental Reactor, a cooperative project between Europe, the United States, China, India, Japan, Russia and South Korea that involves the construction of a prototype fusion reactor to generate electricity. Construction began in 2013 and the reactor is set to go into operation in 2025.