Impact of Axial and Bending Effective Strain on the Tcs of ITER TF Conductors

Given the intrinsic brittleness and strain-sensitive electromechanical behaviour of Nb3Sn, significant efforts have been made in the past to investigate the effects of strain on Nb3Sn based Cable in Conduit Conductors (CICCs). An extensive test campaign was conducted at the SULTAN facility (Villigen, CH) on the ITER TF qualification and production samples. A dedicated campaign was carried out to study the impact of electromagnetic and thermal cycling loads on TF conductors. Finally, a TF conductor sample was tested at the SULTAN facility under conditions relevant to the operation of an ITER TF coil in standalone configuration. These conditions are foreseen for the Magnet Cold Test Bench (MCTB), currently under development at ITER. In this work, the evolution of the current sharing temperature during cyclic loading is analyzed with an approach which distinguishes between the contributions of axial and bending strain, rather than considering one single axial effective strain.