The HT-7U Project and its preliminary engineering design

The HT-7U superconducting tokamak is an advanced steady state plasma experimental device to be built in the Institute of Plasma Physics, the Chinese Academy of Sciences (ASIPP). The mission of the HT-7U Project is to develop scientific issues on the sustainment of a nonburning plasma scenario for the steady-state operation and engineering issues on establishing technology basis of superconducting tokamak. HT-7U will have a long pulse (60-1000 s) capability, a flexible poloidal field system, and auxiliary heating and current drive systems, and will be able to accommodate divertor heat loads that make it an attractive test. The engineering conceptual design and the R and D program for prototypes of HT-7U has begun in 1995. The design of HT-7U incorporates superconducting magnet systems of the toroidal field (TF) and poloidal field (PF). In the beginning of this year, some developments in tokamak design have been made. The R&D programs, including prototype coils of TF and central solenoid (CS), the coordinate test facilities, are being readied. In this paper, an overview of the HT-7U Project and a brief introduction of the general tokamak system with the emphasis on the features structures of TF system, PF system, vacuum vessel, radiation shields and cryostat vessel are provided. The R&D program status are introduced, also