Developments in coil insulation technology for nuclear fusion equipment

In this paper we report on developments in coil insulation systems for use with nuclear fusion apparatus. Insulation systems for high voltage equipment use mica tape, but mica insulation systems have less than adequate properties with respect to large bending strain. For this reason, mica tape is upgraded with the addition of mica flakes and polyimide film. We report on the actual machine insulation systems developed by Hitachi for the Heliotron E, which is a heliotron nuclear fusion device being constructed at Kyoto University. Finally we also report on the insulation systems of the large Tokamak machine JT-60 reactor plasma grade device currently being constructed at the Japan Atomic Energy Research Institute (JAERI). (author)