Southwest Jiaotong University recently announced plans to build a so-called stellarator fusion reactor, joining the worldwide search for alternative, cleaner sources of energy.

The university, located in southwestern China’s Sichuan province, signed an agreement with Japan’s National Institute for Fusion Science (NIFS) on July 3, reported state media outlet China News Service. NIFS already operates a similar reactor in Japan called the Large Helical Device.

Fusion power is created when two or more atoms become one and release energy. Compared with nuclear fission, the atom-splitting process behind present-day nuclear reactors, fusion relies on more abundant fuels while producing less waste and no radiation, said Sheng Zhengmao, a physics professor at Zhejiang University in eastern China. However, the promising source of energy is also exceedingly difficult to control because the atoms need to be heated to more than 100 million degrees Celsius.

“The sun is powered by fusion energy, thus we call [creating a fusion reactor] building an artificial sun,” Sheng told Sixth Tone. “It’s very difficult.”

Many fusion reactors resemble doughnuts. Known as the tokamak design, they suspend the plasma of superheated particles in a double, circular magnetic field. Stellarators, on the other hand, twist a single magnetic field into a helix, which stabilizes the plasma but also complicates the design.

A diagram of the Wendelstein 7-X fusion stellarator in Greifswald, Germany, shows a magnetic coil system (blue) wrapped around a helical plasma source (yellow), with a green line running through the plasma to represent the magnetic field. From the Max Planck Institute for Plasma Physics, licensed under CC BY 3.0.

Chinese researchers have made considerable progress with tokamak designs, thanks to government investment in recent decades, said Sheng. Earlier this month, the Experimental Advanced Superconducting Tokamak (EAST), located in Anhui province, also in eastern China, broke its own world record for longest sustained plasma burn. Due to their complexity, stellarator designs have fewer success stories.

Southwestern Jiaotong University started its fusion science institute in 2014. Its project will receive support from the Institute of Plasma Physics, the division of the Chinese Academy of Sciences that operates EAST, and the Southwestern Institute of Physics, which in the 1970s attempted to build a stellarator called Lingyun. The head of the recently announced project declined Sixth Tone’s interview request.

The cooperation with Japan’s NIFS marks the second time this year a Chinese school has announced an international fusion project. In April, the University of South China, a school in Hunan province with a strong nuclear research program, reached an agreement to work with the Australian National University in Canberra to research fusion energy and import a stellarator from Australia.

Sun Xuan, a physics professor at the University of Science and Technology of China in Anhui, told Sixth Tone that collaborating with countries that have a rich background in fusion research can help Chinese scientists catch up with international fusion research.

Together with the European Union, Japan, the United States, and other countries, China joined the ITER program to build a tokamak reactor in France. The country also has plans to build another new fusion reactor called the Chinese Fusion Engineering Test Reactor — which would be even bigger than ITER — by 2030.

Sun hopes that international cooperation can help speed up fusion research, as there is still a long way to go before arriving at commercially viable fusion energy. Currently, no reactor has managed to generate more energy than is needed to produce the plasma.

“The challenge is big,” Sun said. A joke nuclear scientists like to make is that fusion energy will always be 30 years away. “It’s self-mockery by the scientists, but it’s true,” he said.

Editor: Kevin Schoenmakers.

(Header image: A view of the tokamak fusion reactor in Hefei, Anhui province, Jan. 15, 2008. VCG)