Tungsten: Vital metal for 'artificial sun'

Tungsten has become the vital material for the 'artificial sun'. It is reported that the all-superconducting Experimental Advanced Superconducting Tokamak (EAST) reactor, known as the 'artificial sun' by the Hefei Institute of Material Science, Chinese Academy of Sciences, will soon complete a new round of upgrades to a core electron temperature of 100 million degrees Celsius. The new scientific research goal of 100-second pulse tungsten plasma material launched a challenge, and push the world's controllable nuclear fusion energy research to a new era.

artificial sun china temperature record image

The operating principle of EAST is to add a small amount of hydrogen isotope deuterium or tritium into the vacuum chamber of the device, generate plasma through a principle similar to a transformer, and then increase its density and temperature to cause a fusion reaction, which generates huge energy during the reaction. The raw materials required for nuclear fusion reactions are quite inexhaustible on the earth. The products are also relatively friendly to the ecological environment which effectively alleviate the usage of fossil fuels.

Since its establishment, EAST has carried out more than 96,000 experiments. In September 2006, its first plasma discharge was successful. In 2012, it broke the world record and obtained 20 million degrees high-parameter divertor plasma for more than 400 seconds, and at the same time, it obtained stable high-confinement plasma discharge for more than 30 seconds.

In November 2016, a completely non-inductive current-driven high-confinement plasma was obtained for more than 60 seconds. In July 2017, a stable 101.2-second steady-state long pulse high-confinement plasma operation was achieved, creating a new record. In 2018, under the coordinated heating of electron cyclotron and low clutter, the electron temperature in the plasma center reached 100 million degrees Celsius and the plasma continued to operate for 20 seconds.

Starting from July 2020, EAST has launched a new round of upgrades, implementing a series of major improvements in cutting-edge materials, key components, and main subsystems. Jiefeng Wu, director of the Research and Development Center of the Institute of Plasma Physics, Chinese Academy of Sciences, said, "The artificial sun is quite complicated. It requires a high temperature of hundreds of millions of degrees Celsius and a low temperature of minus 269 degrees Celsius to coexist within 1 meter. There are tens of thousands of parts and components with a little flaw."

China's tungsten industry has made a great contribution to EAST manufacturing. Tungsten plasma-oriented materials are one of the key factors for the ‘artificial sun’ to advance towards the 100-million-degree Celsius 100-second goal.

Thanks to the transition of metal tungsten, a breakthrough in the performance of the traditional 'artificial sun' shows a possibility. W has the advantages of high melting point, high thermal conductivity, low hydrogen adsorption, low physical sputtering rate, high sputtering threshold energy, low fuel retention, low evaporation rate, and no radioactivity. It is recognized as the plasma-oriented material of EAST.

Xianzu Gong, director of the Tokamak Physics Laboratory of the Institute of Plasma Physics, Chinese Academy of Sciences, introduced that the EAST upgrade and transformation work is progressing smoothly. It is expected that the transformation will be completed at the end of April and will launch an impact on the new target of ‘100 million degrees Celsius for 100 seconds.’

 

WeChat