Research and development studies for fusion reactor materials are briefly reviewed. The emphasis of this paper is to explain importance of heavy irradiation effects in the fusion environment and to introduce recent efforts on heavy irradiation effects for fusion reactor materials. The strategy of Japanese materials research group and future plans for irradiation experiments are briefly mentioned.
A number of conceptual designs of fusion reactors have been proposed. The larger the fusion reactors are, the more important the structural engineering is in order to ensure the integrity of the fusion reactor. In this paper, from such viewpoint as the structural engineering, the method of the structural analysis for fusion reactors is presented and the examples of the structural analysis, including the thermal stress analysis and the electormagnetic field analysis, are illustrated.
Maintenance is an important technology element in a fusion reactor. Design is dominated by maintenance in some meaning. Content of the maintenance applied to a fusion reactor is described first and then hardware available to the maintenance is introduced.
From particle orbit point of view, a tokamak is a combined confinement configuration where a closed toroidal volume is surrounded by an open confinement system like a magnetic mirror. By eliminating a cold halo plasma, the energy loss from the plasma becomes convective. The H-mode in diverted tokamaks is an example. Because of the favorable scaling of the energy confinement time with temperature, the performance of the tokamak may be significantly improved by taking advantage of this effect.
Methods are studied for reconstructing the radiation intensity distribution of plasma from its projection in a direction tangential to torus. The adaptation of spline function model to the image in poloidal plane gives a good result by determining knots adequately in number and location with the Akaike information criterion assisted by spatial derivative estimation. A nonlinear optimization is adopted for the guarantee of nonnegative intensity estimate. The method, which is also applicable to the tomography with cross-sectional projections, is compared with the ART and MEM in analyzing numerically generated projections and X-ray imaging data of tokamak.