Status and problems of fusion reactor development

Thermonuclear fusion of deuterium and tritium constitutes an enormous poten tial for a safe, environmentally compatible and sustainable energy supply. The fuel source is practically inexhaustible. Further, the safety prospects of a fusion reactor are quite favourable due to the inherently self-limiti ng fusion process, the limited radiologic toxicity and the passive cooling property. Among a small number of approaches, the concept of toroidal magne tic confinement of fusion plasmas has achieved most impressive scientific a nd technical progress towards energy release by thermonuclear burn of deute rium-tritium fuels. The status of thermonuclear fusion research activity wo rld-wide is reviewed and present solutions to the complicated physical and technological problems are presented. These problems comprise plasma heatin g, confinement and exhaust of energy and particles, plasma stability, alpha particle heating, fusion reactor materials, reactor safety and environment al compatibility. The results and the high scientific level of this interna tional research activity provide a sound basis for the realisation of the I nternational Thermonuclear Experimental Reactor (ITER), whose goal is to de monstrate the scientific and technological feasibility of a fusion energy s ource for peaceful purposes.