Some technology issues for the general assembly of EAST superconducting Tokamak

Abstract

The construction of experimental advanced superconducting Tokamak (EAST) was completed at the Institute of Plasma Physics of Chinese Academy of Sciences (CASIPP) in January of 2006 after challenging techniques over the period of 8 years. The followed cooling-down test was also successfully performed and all superconducting magnets including two current leads and seven bus lines entered the cryogenic superconducting state smoothly. Total 260 shots have been fired. The longest TF current duration was 5000 s and the highest TF current was 8200 A (2T). All the testing results showed that the EAST machine and its sub-systems have been successfully built. EAST machine is a fully superconducting Tokamak. It consists of more 20,000 parts and possesses the configuration of 7600 mm in diameter, 6600 mm in height and the weight of 400 tonnes. The complicated general assembly of EAST began in July of 2003 and nearly took two and half years. During the process, not only a series of common difficulties for a large Tokamak but also many technique problems for a superconducting Tokamak itself needed to be solved properly. This paper emphasizes on some key technology issues that were faced and solved in EAST assembly process including optimization of assembly procedure, survey and alignment, ensuring of thermal insulation gap, installation of unique parts, treatment of electric insulation, improvement on heat conduction, control on deformation of vacuum vessel, etc. Besides, the quality control (QC), which made important contributions to the general assembly is also described.