Properties of Toroidal Field Nb3Sn Strands Made for the ITER Chinese Domestic Agency

Abstract

China was responsible for supplying 7.5% of ITER toroidal field (TF) Nb 3 Sn conductors. It has delivered all the required conductors unit lengths and fulfilled the TF conductor package. The conductor package delivery consisted of four phases, in terms of phase I (call for tender), II (qualification process), III (pre-production process), and IV (production process). This paper focuses on work from phases II to IV. The Superconducting Strand Test Laboratory of the Institute of Plasma Physics Chinese Academy of Sciences (ASIPP) was the reference laboratory of the Chinese Domestic Agency and undertook the task of Nb 3 Sn strands verification based on the requirements of ITER procurement arrangements. The verification results showed that the strands properties fulfill ITER specifications. In addition, in order to know well the strand properties and supply essential data for conductors' performance prediction and analysis, the mechanical properties and critical current Ic as a function of axial strain, temperature, and magnetic field for the TF strands have been tested and summarized.