Test and Analysis of China's First Short Conductor Sample for ITER Toroidal Field Coils

In the framework of the ITER qualification tests, the first China TF conductor sample (CNTF1) was tested at the SULTAN facility. The sample was made of two TF conductor sections manufactured from identical internal stannum strands provided by the Oxford Superconducting technology company (OST). In order to evaluate the conductor performance, the current sharing temperature (Tcs) was measured at specified electromagnetic load cycling steps. Both conductor sections of the CNTF1 sample showed identical performance. Tcs was 7.2 K before cycling loading, and 6.9 K even after 950 cycles, without significant degradation, which substantially exceeds the ITER requirement of 5.7 K. The tests of the CNTF1 conductor sample showed that the electromagnetic cyclic load exhibited a negligible effect on the conductor performance. The coupling time constant θ for AC loss was 214 ms and 71.52 ms before and after the cycling load, respectively. The test results of the sample are compared with the strand performance and parameter model analysis.