Recent progress in wall material development and of surface technology for fusion devices at the Japan Atomic Energy Research Institute

Abstract

The research and development of materials and material processes associated with the plasma–wall interaction in magnetically confined fusion devices includes current and near-term problems which must be solved to advance plasma confinement research. The major elements to be considered for the materials and processes are (a) impurity release and surface modification; (b) hydrogen isotope recycling, retention, and permeation; (c) high heat flux removal and thermomechanical response; and (d) the effects of plasma disruptions. The development of wall materials and processes and the associated plasma–wall interaction study at the Japan Atomic Energy Research Institute have been carried out primarily from the device-oriented standpoint. The weight is laid on the development and performance tests of new materials and processes for plasma-interactive components. In the JT-60 tokamak, TiC-coated molybdenum and TiC-coated Inconel tiles are currently used as most plasma-interactive components. The JAERI coating program also includes the development of in situ coating techniques for TiC and C. For the near-term devices, actively cooled components will be developed. The major technical issues are to improve ceramic materials and to develop ceramic–metal bondings which satisfy the requirements specific to fusion devices.