Design assessment of heliotron reactor

摘要

Helical reactor designs are studied on the basis of the physics and engineering concept of the Large Hclical Device (LHD), which is characterized by two advantages: an efficient, closed helical divertor and a simplified continuous coil syste. First, optimization studies of lota=2 conventional LHD type reactors (LHD-R) have been carried out. One point plasma modelling, in addition to 3-D equilibrium/1-D transport analysis, has clarified the D-T ignition condition. An accessible design window for reactor parameters is found by using physics and engineering constrains. A cost estimate suggests the importance of the compact design in reducing the cost of electricity. Second, a new reactor design candidate, the modular heliotron reactor (MHR), is proposed; it is focused on the advantage of an efficient helical divertor that is compatible with the modular helical coil system. A special coil winding system permits an appropriate coil gap for reactor module maintenance, and makes good plasma confinement and an efficient helical divertor configuration compatible with each other. Two MHR design options are selected on the basis of the LHD-R system analysis. Third, by making use of the advantage of the simplified continuous coil design, a high field force free helical reactor (FFHR) is proposed in order to reduce the electromagnetic force by adopting an lota=3 force free like continuous coil system. The molten salt FLiBe, LiF-BeF_2, is selected in FFHR as a self-cooling tritium breeder, from the viewpoint of safety and compatibility with the high magnetic field design.