AbstractThe TOKI-MC (called “Module Coil” before), a superconducting solenoid, is one of the R&D coils for the Large Helical Device (LHD). The coil was made of one of the candidate conductors for the helical coils on its actual size. Being rated at 20 kA operating current and 11 MJ stored energy, the coil was designed to simulate almost all major parameters of the helical coils, i.e., conductor torsional rate, electromagnetic force of 10 MN/m, operating current, magnetic field of 7.7 T, current density in the winding of 40 A/mm2, and pool-boiling cooling method. The conductors had 19 mm square cross sections and are a composite of NbTiCu compacted cable, aluminum stabilizer, and copper mechanical sheath. The conductors were wound with a maximum torsional rate of 36°/m on a three-dimensionally shaped stainless-steel winding form. The coil forming was operated in twist-and-wind way piece by piece. Seven conductors were wound in layers with 0.4 m inner diameter, 0.7 m outer diameter, and 0.4 m height. The finished winding was canned into a stainless-steel coil case, having a mass of 5300 kg altogether.
A continuous winding scheme for superconducting tokamak coils with cable-in-conduit conductor