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China has achieved a significant breakthrough in its ambitious “artificial sun” program by developing and scaling up production of a critical component that previously had to be imported, researchers announced Tuesday. A team at the Institute of Metal Research (IMR) under the Chinese Academy of Sciences successfully developed a domestic purification technology for Hastelloy (C276) metallic substrates. This component is essential for building the powerful “super magnets” at the heart of a nuclear fusion device. According to Professor Rong Lijian, who led the research, this solves a major strategic bottleneck. While China is a leader in superconducting materials, the nation has long relied on costly and uncertain imports for the C276 substrates, as reported by Global Times. This breakthrough provides a crucial, domestically-sourced material for the Burning Plasma Experimental Superconducting Tokamak, the “artificial sun” currently under construction in Hefei. For this, China’s Foreign Ministry spokesperson Mao Ning said, “The Burning Plasma Experimental Superconducting Tokamak (#BEST) is set for completion in 2027 and could become the first in human history to generate electricity from fusion.” Quest for a stable foundation Controlled nuclear fusion devices work by confining plasma at temperatures exceeding 100 million degrees Celsius. This requires immensely powerful magnetic fields, which are generated by second-generation high-temperature superconducting tapes. The IMR’s statement explains that the C276 substrate acts as the “foundation of a building” for these tapes. The superconducting material must “grow” layer by layer on top of this substrate. It not only provides the mechanical strength for the tape but also serves as the essential base for the entire superconducting structure’s stability. “Our team has accumulated nearly 20 years of experience in developing high-purity materials,” said Rong, noting it took them less than two years to overcome the specific processing challenges for this substrate. China’s next-gen nuclear fusion device The new domestically-produced alloy is described as “ultra-pure,” with impurity levels for elements like carbon, oxygen, and sulfur falling below those found in similar imported materials. They overcame the processing challenge, producing a metallic strip over 2,000 meters long yet just 0.046 millimeters thick, with a mirror-like surface roughness of less than 20 nanometers. When cooled with liquid nitrogen, the material’s tensile strength surpasses 1,900 MPa. To illustrate, this means a fingernail-sized piece could support the weight of 190 tons. It also demonstrated excellent thermal stability, retaining high strength even after being heated to 900°C (1,652 degree Fahrenheit). Earlier, China’s next-generation nuclear fusion research device, BEST, entered a new construction phase involving the assembly of its main machine. According to the project team, the successful installation of the Dewar base provides the foundation for assembling the reactor’s core systems. For context, the Dewar is a large, vacuum-insulated vessel designed to maintain the cryogenic temperatures required for the device’s powerful superconducting magnets to operate. Notably, the BEST device is one of several major global fusion projects and is intended to be the first to demonstrate electricity generation practically.
