AC loss analysis and calculation of superconducting joints for EAST TF coils

EAST is a full superconducting Tokamak with superconducting toroidal field (TF) and poloidal field (PF) magnets designed with NbTi cable-in-conduit conductors. Superconducting joints have been used due to the limitations of conductor piece length and connections between magnets. The overlap joint twin box type is developed for the TF coil outer joints to connect 16 D shape TF magnets. The 17 TF coil outer joints constitute a loop parallel to the PF coil systems, so the rapid variation of magnetic field will induce high AC losses in the TF coil outer joints. In this paper, AC losses and Joule heating of these joints during a plasma scenario are analyzed and calculated, and the temperature rise of helium in joints is also estimated by a simple heat balance.