Performance of JT-60SA toroidal field coils in light of strand and conductor test results

The Toroidal Field system of the JT-60SA tokamak is composed of 18 NbTi superconducting coils all individually tested in the Cold Test Facility (CTF, CEA/IRFU Saclay, France). The test program includes for each coil a progressive operating temperature increase at nominal current (25.7 kA) up to quench followed by a safety discharge. To account for the heat coming from the casing to the winding pack (WP), a transient test procedure was settled so as to trigger the quench at peak field in the coil; nevertheless the quench location was identified on a side double-pancake in the first two tested coils. We present the CEA analyses for the quench test of the second coil which showed similar behavior as the first one but received a more extensive instrumentation. The coil performance is analyzed in light of the NbTi strand superconducting properties coming from the strand characterization program and of the full size conductor tests carried out by CEA in the SULTAN facility. These analyses involve cable thermal and electrical modelling developed at CEA and already used in ITER R&D, design and characterization programs. (C) 2017 Published by Elsevier B.V.