Current status of nuclear fusion development and progress of technology in Hitachi

Recently, the technical development for realizing nuclear fusion reactors has achieved conspicuous progress such as the construction of a critical plasma experimental apparatus. In this paper, by outlining the construction of various experimental apparatuses and the main development of elemental technology by Hitachi Ltd., the recent trend of development is discussed. As the development of nuclear fusion shifts from scientific verification phase to technological verification phase, the role achieved by industrial circles increases. For future nuclear fusion reactors, a wide range of the technological research is required, and through the design studies, the subjects of development become clear. Besides the attempt to realize steady tokamak reactors applying high frequency heating techniques and the technical advance of superconducting magnets and second stage plasma heating, also the new movement such as the improved tokamak system to make the apparatuses compact is seen. As for the increase of apparatus size, the magnetic energy of main coils grew by about 1000 times for 15 years. JT-60, Heliotron E, TRIAM-1M, JIPP T-2U, REPUTE-1 and others are described. (Kako, I.)