The key technology research of electron beam welding in CFETR vacuum vessel collar

Chinese Fusion Engineering Testing Reactor(CFETR) is a fully superconducting magnet Tokamak, and the key components of CFETR have been studied. As one of the pre-research projects, 1/8 full-scale vacuum vessel(VV) aims to grasp the key technology of molding, welding, non-destructive testing and measurement in the aspect of building a large-scale vacuum vessel, and accumulate experience for the formal construction of CFETR. The project has been officially launched by Institute of Plasma Physics Chinese Academy of Sciences(ASIPP) in 2015. In the manufacturing process of 1/8 full-scale VV, the electron beam welding is adopted at the VV collar in order to reduce welding deformation. As a large-scale electron beam welding (EBW) system set up in ASIPP, the research work of electron beam welding technology has been carried out, with periodical achievements obtained. This paper will introduce the key technology and research progress of the electron beam welding for the VV collar in detail.