Design of JT-60SA thermal shield and cryodistribution

Kamiya, Koji; Onishi, Yoshihiro; Ichige, Toshikatsu; Furukawa, Masato; Murakami, Haruyuki; Kizu, Kaname; Tsuchiya, Katsuhiko; Yoshida, Kiyoshi; Mizumaki, Shoichi*

The JT-60 plans to be upgraded to a full-superconducting tokamak referred as the JT-60 Super Advance (JT-60SA) as one of the JA-EU broader approach projects. In the JT-60SA, the superconducting magnets are surrounded by thermal shield cooled at 80 K, which is categorized into 3 groups; the vacuum vessel thermal shield (VVTS), the port thermal shield (PTS) and the cryostat thermal shield (CTS). In this study, seismic analysis was conducted for the thermal shield to confirm the soundness of the latest design, taking the dynamical analysis into account. Trial manufacturing of a 10 degree outer VVTS was also conducted. The outer VVTS was subsequently assembled with already existing inner VVTS to measure the total tolerance (manufacturing plus assembly). It was found that the total tolerance was 5.2 mm which is less than the target tolerance of 10 mm. Finally, concept and the current status of the JT-60SA cryodistribution design are reported.