Test Results and Investigation of Tcs Degradation in Japanese ITER CS Conductor Samples

Japan Atomic Energy Agency (JAEA) has fabricated and tested the four conductor samples composed of high performance strands manufactured by the bronze-route process for the ITER Central Solenoid (CS) conductor. The current sharing temperature (Tcs) electrically assessed at 45.1 K and 10.85 T along the cycling loading at 48.8 kA and 10.85 T initially were 6.0 K and 6.1 K, and then 5.3 K and 5.5 K after 6000 cycles for the first SULTAN sample named JACS01, respectively. As results of second SULTAN sample named JACS02, the Tcs values initially were 7.2 K and 6.8 K, and then 6.6 K and 6.1 K after 10000 cycles for each conductor, respectively. The Tcs degradation was not saturated at the end of the test campaign. From the destructive observation, the large bending at the low transverse loading side in the high field zone was observed. The strand buckling and accumulating by slipping between the cable and the jacket are considered.