Prospects of fusion energy system

Nuclear fusion energy that collects large expectation as the energy system of 21st century adopts the tokamak with DT fuel as the main line to advance the research and development, and succeeded in the confinement of plasma that nearly satisfies the condition of zero power output. However, as for nuclear fusion energy, other various generation and utilization forms are conceivable. At present, there are many subjects before the practical use, but as to nuclear fusion energy system which is considered to contribute greatly to mankind when it will be practically used in future, it is significant to clarify the present state of the research and the subjects of the research for the realization. Tokamak type fusion reactor, helical type fusion reactor, D-He-3 FRC fusion reactor, inertial fusion reactor,fusion-fission hybrid reactor, nuclear fusion rocket, muon catalytic nuclear fusion, normal temperature nuclear fusion and so on are described. As the final summary, on the basis of the concepts of individual nuclear fusion reactors, what possibility nuclear fusion energy has as a whole is considered, and the way of advancing the development hereafter is summarized. (K.I.)