This photo taken on Oct. 1, 2025 shows the base of the Burning Plasma Experimental Superconducting Tokamak (BEST) in Hefei, east China's Anhui Province. (Xinhua/Zhou Mu)

The Burning Plasma Experimental Superconducting Tokamak (BEST), a compact fusion experiment device under construction in Hefei, east China's Anhui Province, has reached a major milestone with the successful installation of its first key component, the Dewar base, marking progress toward the world's first electricity generation from fusion power.

Fusion energy, often hailed as the ideal "ultimate energy source," seeks to replicate the nuclear fusion process that powers the sun. Unlike previous fusion experimental devices, BEST is designed to demonstrate actual "burning" of deuterium-tritium plasma. Since the project's full-scale assembly began in May this year, the facility has attracted significant public attention.

At the heart of BEST lies the Dewar, a core component that functions like a giant high-vacuum thermos flask. It insulates the superconducting magnets, which must operate at minus 269 degrees Celsius, enabling them to confine plasma heated to over 100 million degrees.

A drone photo taken on Oct. 1, 2025 shows the construction site of the Burning Plasma Experimental Superconducting Tokamak (BEST) in Hefei, east China's Anhui Province. (Xinhua/Zhou Mu)

Huang Xiongyi, associate researcher with the Chinese Academy of Sciences' Institute of Plasma Physics, said on Wednesday that the Dewar base serves as the foundation of BEST and will eventually support more than 6,000 tonnes of equipment.

Weighing over 400 tonnes, measuring about 18 meters in diameter and 5 meters in height, the Dewar base is not only the heaviest single component of BEST's main machine, but also the largest vacuum component ever produced in China's fusion research field.

According to Huang, the development of the Dewar base required breakthroughs in multiple advanced technical areas, including high-precision forming and welding, millimeter-scale deformation control, and ultra-high vacuum sealing. These challenges were successfully overcome, resulting in millimeter-level precision during installation.

With the Dewar base successfully installed, other core components of the main machine will be gradually assembled, and the BEST device is scheduled for completion by the end of 2027.