Assembly of the superconducting tokamak EAST

EAST is a new machine, Experimental Advanced Superconducting Tokamak, being built in CASIPP. Steady-state operation is a main mission for this machine and the superconducting magnets were all poloidal field and toroidal field systems, constituting an engineering mission to establish the technology basis of chosen to be full superconducting Tokamak to investigate a future fusion device. The parameters of EAST are: the main radius is 1.7 m and the minor radius is 0.4 m, with a maximum toroidal magnetic field of 3.5 Tesla at the plasma center. The plasma current is 1 MA, the pulse length is 1000 s, elongation is about 1.6 - 2.0, and triangularity is about 0.4 - 0.6. The EAST device has a large number of components to be assembled at the main building since June 18, 2003. These include: support structure, cryostat, thermal shields, vacuum vessel, toroidal field magnets, poloidal field magnets, current leads and joints, cooling tubes and insulators, first wall and other auxiliary systems. In this device the required assembly should maintain gaps and insulation blocks between toroidal field magnets, thermal shields and vacuum vessel. It was required to meet the tolerances for accurate positioning of the components in the radial, toroidal, poloidal and vertical directions, to ensure that the machine satisfied the requirements and to minimize subsequent corrective operations. This paper presents a brief description of the device in terms of design, fabrication, testing and assembly.