440-ton field coil box delivered for world’s largest fusion magnet system

Shanghai Electric has successfully delivered the world’s largest toroidal field magnet coil box, a critical component for China’s fusion energy efforts. Weighing approximately 880,000 pounds and made from ultra-low-temperature austenitic steel, the coil box surpasses similar components used in France’s ITER project in both size and weight. The development process took five years and involved overcoming significant technical challenges, including advanced welding techniques on steel up to 14 inches thick, combining high-thickness laser welding with ultra-deep narrow-gap tungsten inert gas welding and phased array non-destructive testing to ensure precision. This achievement not only advances China’s capabilities in fusion technology but also supports the establishment of a comprehensive industrial supply chain for fusion energy. The innovations derived from this project have potential applications beyond fusion, including aerospace, energy equipment, shipbuilding, and offshore engineering. Additionally, the Institute of Plasma Physics at the Chinese Academy of Sciences is nearing completion of the Comprehensive Research Facility for Fusion Technology (CRAFT), designed to address