Performance of ITER Correction Busbar Conductor Samples CBCN2 and CBCN3

The correction busbar (CB) conductors for the ITER project are being produced in China. The second China CB conductor sample (CBCN2, Phase II of conductor testing) and the third CB conductor sample (CBCN3, Phase III testing) were made of the WST NbTi strands, cabled by Changtong, jacketed at ASIPP, and tested in the SULTAN facility. The current sharing (Tcs) test results show that the conductor sections of CBCN2 and CBCN3 have high Tcs performance. Using the electrical method, the Tcs of both CBCN2 and CBCN3 samples was 7.50 K at 10 kA /2.9 T (maximum operating field) before and after electromagnetic loading. AC loss measurement was performed before any electromagnetic loading of the sample and the measurements were repeated after 1000 or 2000 cyclic loads. The AC loss measurements were performed at 2 T background field, without transport current. The AC loss of the CBCN2 and CBCN3 conductors slightly differs at ±0.2T AC field and various frequencies. According to the SULTAN test result, Tcs of CBCN2 and CBCN3 conductor samples meet the ITER acceptance criteria of 7.0 K at Bpeak field is 2.9 T and 10 kA.