Development of Central Solenoid for JT-60SA

Several components for central solenoid (CS) of JT-60 Super Advanced (JT-60SA) were newly developed and tested. The butt-type joint, the electrical resistance of which is about 2 nΩ, was developed to increase the winding diameter. The insulation system, which consists of Glass/Kapton/Glass tape and Bisphenol A diglycidyl ether (DGEBA) epoxy, showed sufficient tensile strength after the irradiation of 100 kGy. Insulation characteristics of 4 × 4 winding stack sample after the compression of 705 kN 36 000 times was able to withstand voltages larger than 21 kV. The heat treatment and transfer of the CS model coil with superconductor were conducted. The pancake temperature during flat top was maintained at 923 ± 4 K. The maximum temperature difference in the pancake was 30 K. All manufacturing processes were confirmed so that the mass production of CS will be started in 2013.