Achievement of precise assembly of the JT-60SA superconducting tokamak

Abstract

The JT-60 Super Advanced (JT-60SA) tokamak was constructed with very tight tolerances for assembly and handling of heavy components in an enclosed space. Millimetre-order precision was required for the tokamak assembly, not only to avoid mechanical interference, but also to obtain good plasma performance by keeping the magnetic error field low. This effort entailed the development of numerous unique procedures. This paper reports on these procedures, focusing on assembly and testing of the final sector of the vacuum vessel, the central solenoid, top parts of the tokamak, and the in-vessel components.