Investigation of Strand Bending in the He-Inlet During Reaction Heat Treatment for ITER TF Coils

To evaluate presences of performance degradation due to strand bending in Nb3Sn cables, methods for investigating strand bending in Nb3Sn cables were developed by JAEA and demonstrated for the He-inlets of the ITER toroidal field coils. Conductor elongation and residual strain during the reaction heat treatment were measured. In addition, high-resolution X-ray computerized tomography was used to visually search for strand bending in the Nb3Sn cable. As a result, no large strand bending was observed.