Series Production of ITER TF Coil in Japan- Double-Pancake and Winding Pack Insulation

Quantum and Radiological Science and Technology (QST), a Japan Domestic Agency in ITER, is responsible for procuring nine ITER Toroidal Field coils. QST developed an optimized manufacturing plan to solve technical issues in double-pancake (DP) fabrication and winding pack (WP) fabrication, such as optimization of inter-DP glass fabric thickness to avoid damage of DP and WP insulation and degradation of conductor near joint due to glass fabric compression during WP insulation and impregnation. To this purpose, DP thickness was successfully increased by 3 mm by putting glass fabric during DP insulation. Then, this compensates local distortion, which is originated by cover plate (CP) welding and difficult to correct. This DP expansion made it easier to achieve tight tolerance in the WP height. The series production of DP and WP then proceeded and 31 DP winding, 15 DP impregnation, and curing of first WP impregnation was completed in Japan.