61. 臨界プラズマ試験装置の試作開発,(II)

The present peport describes the research and development (R & D) of poloidal field coils in the JAERI large tokamak JT-60. The R & D is classified into two development stages of basic techniques and of fabrication procedures. The first stage includes the development of the demountable mechanical joint, the turn-to-turn connection, the welding process of copper conductors, the insulation system and the cooling system. The most suitable mechanical joint is selected from about 30 types of joint structures. The turn-to-turn connection chosen is a pin-jointed one using FRP insulation. A welding process without preheating is chosen for the connection of conductors. A resinrich mica-epoxy insulation system is adopted for the most part of the conductor, while the mechanical joint is insulated with a unique insulation system using FRP covers and resin-rich mica tapes. The contact resistance of the mechanical loint and its temperature distribution when a current is driven through it are measured before and after the application of cyclically loaded mechanical forces simulating the electromagnetic forces. In the second development stage, a full scale two-turn ohmic heating coil and a full scale 90° magnetic limiter coil sector are fabricated using the basic fabrication techniques mentioned above and tested to examine their mechanical, electrical and thermal properties. It is found that the developed techniques and procedures are applicable to the construction of JT-60 poloidal field coils.