Present status of high heat flux experiments in relation to fusion reactors

Many researches and developments related to high heat flux machinery and equipment such as the first wall, diverter-limiter and beam dump of a fusion reactor have been in progress. For the purpose of elucidating the effect that unsteady thermal load exerts on the machinery and equipment at the time of disruption, the simulation experiments using electron beam or ion beam as heat sources have been carried out. Regarding high heat flux heat removal, there are many experiments on beam dumps. As the materials for high heat flux machinery and equipment, the use of bonded materials is promising, and the research and development of graphite-metal bonded materials for the first walls and limiters, and W-Cu bonded material for diverter walls have been advanced. In this paper, the present status of these research and development is outlined. In the research and development of nuclear fusion, the attainment of critical plasma is imminent, and the next stage apparatuses are investigated concretely. Their main mission is to attain self ignition and long burning. The first wall and the diverter-limiter are used under severe environment, and their reliability and soundness demand the research and development hereafter. The loading condition and problems of the machinery and equipment around plasma are discussed. (Kako, I.)