Recently, EAST team fabricated full-scaled Vacuum Vessel (VV) sector for China Fusion Engineering Test Reactor (CFETR) and developed key technologies in the manufacturing process of VV. This research was conducted by researchers led by Prof. WU Jiefeng from the Institute of Plasma Physics, Hefei Institutes of Physical Science. 

The VV is one of the most critical components of the CFETR facility. It provides an ultra-vacuum environment for high-temperature plasma and the initial shield for nuclear radiation.

The team successfully completed the fabrication of the VV mock up. At the same time, the key technologies were developed such as the high-precision forming of the hyperbolic shell, the welding deformation control of 50mm-thick full penetration structure, the nondestructive testing of the complex welds by full volume covering, the establishment of high-precision 3D measurement fiducial network and the high-precision assembly of the VV sector.

Based on the current design, the VV was toroidally divided into eight 45° sectors. Each sector was a double-walled steel component weighing 300 tons and measuring 19.4m in height and 7.5m in width, with multiple port extensions. The allowance fabrication tolerance for 45° sector was specified to be less than ±8 mm.

Due to the large scale and tight manufacturing tolerances, the researchers began the fabrication and testing of a full-scaled VV sector mockup to ensure the structural integrity of the CFETR VV.

The study was supported by the Comprehensive Research Facility for Fusion Technology Program of China and the China National Magnetic Confinement Fusion Science Program.

The VV sector mockup (Image by the research team)