Manufacture of the Winding Pack and Development of Key Parts for the JT-60SA Poloidal Field Coils

Manufacture of poloidal field (PF) coil system in JT-60SA is progressing. Recently, fabrication of the winding machines for equilibrium field (EF) coils and central solenoid (CS) were completed and the winding with the superconducting conductor was started for an EF coil (EF4). A few double pancake (DP) coils for EF4 were fabricated, and it was realized that the error of circularity for DP coils became less than the designed value. Design of the conductor end structure was also progressed. This part had the role of restraining the conductor end to prevent its separation from the winding pack. It was confirmed by the structural analysis that the conductor end structure for CS, which receives the large electromagnetic (EM) force, had sufficient mechanical strength. It was also checked by the cold test that this structure satisfied the designed performance for the electrical isolation in addition to the mechanical performance. Regarding the design of the inlet for CS, mechanical reinforcement was considered for its structure. Final design of CS inlet was determined by structural analysis to confirm the sufficient mechanical strength against the vertical compression induced by EM forces.