Annual report of Naka Fusion Research Establishment from April 1, 2002 to March 31, 2003

This annual report provides an overview of research and development (R and D) activities at Naka Fusion Research Establishment, including those performed in collaboration with other research establishments of JAERI, research institutes, and universities, during the period from 1 April, 2002 to 31 March, 2003. The activities in the Naka Fusion Research Establishment are highlighted by high performance plasma researches in JT-60 and JFT-2M, research and development of fusion reactor technologies towards ITER and fusion power demonstration plants, and activities in support of ITER design and construction. JT-60 program has continued to produce fruitful knowledge and understanding necessary to achieve reactor relevant performances of tokamak fusion devices. JFT-2M has made contributions in more basic areas of tokamak plasma research and development in pursuit of high performance plasma. The objectives of JT-60 research have been more shifted to physics R and Ds in support of the International Thermonuclear Experimental Reactor (ITER) and establishment of physics basis for a steady state tokamak fusion reactor like SSTR as a fusion power demonstration plant. In JFT-2M, the advanced material tokamak experiment program has been carried out to test the low activation ferritic steel for development of the structural material for a fusion reactor. In the area of theories and analyses, significant progress has been made in understanding of the ITB, energy confinement scaling in ITB plasmas, MHD equilibrium in the current hole region, asymmetric feature of divertor plasmas and the divertor detachment. In addition, through the project of numerical experiment on tokamak, the mechanism of the ion temperature gradient mode was clarified by particle simulations. The physics of divertor plasma was also studied by particle simulations. R and Ds of fusion reactor technologies have been carried out both to further improve technologies necessary for ITER construction, and to accumulate technological database to assure the design of fusion power demonstration plants, which include the development of Blanket Test Modules to be tested by ITER, reduced activation structural materials, and their neutron irradiation facility, now called the International Fusion Materials Irradiation Facility (IFMIF). In the ITER Program, Canada made the first site proposal to host ITER in June 2001 and three additional site offers including Japanese Rokkasho proposal were submitted in June 2002. Fourteen years after the inception of ITER, construction of ITER has come close to a reality. JAERI as the main implementation institute of the ITER program in Japan, has made major technical contributions in preparing the Japanese site proposal and licensing procedures. JAERI has also coordinated scientific and technical activities in support of ITER collaborating with universities and other research institutions in Japan. (J.P.N.)