Performance of first insert coil with REBCO CICC sub-size cable exceeding 6 kA at 21 T magnetic field

• Published in: Superconductor science & technology Vol. 35; no. 11; pp. 114003 - 114010
• Main Authors: Zhou, Chao, Jin, Huan, Fang, Zhen, Xiao, Guanyu, Ma, Hongjun, Liu, Fang, Liu, Huajun, Ma, Tao, Tan, Yunfei, Chen, Wenge, Wu, Zuojiafeng, Kanazawa, Shintetsu, Nijhuis, Arend, Devred, Arnaud, Li, Jiangang, Qin, Jinggang
• Format: Journal Article
• Language: English
• Published: IOP Publishing 01.11.2022
• Subjects: electromagnetic load; high field; REBCO insert solenoid; warm-up-cool-down treatment
• ISSN: 0953-2048; 1361-6668
• DOI: 10.1088/1361-6668/ac8cbc

Abstract The Institute of Plasma Physics at the Chinese Academy of Sciences is developing the REBCO cable in conduit conductor (CICC) technology for applications in next-generation nuclear fusion devices. The aim is to develop a CICC comprised of six REBCO sub-cables to satisfy the requirements of operation with a current of around 40 kA and a peak field of up to 20 T. To qualify the performance of the sub-size REBCO cable to be used in the CICC, two 25-turn insert solenoids have been designed, manufactured and tested at a current exceeding 6 kA subjected in a background field supplied by a water-cooled resistive magnet. The insert solenoid, wound from a 11.5 m long REBCO CORC ® cable, was designed to investigate its current carrying capacity under high field and electromagnetic (EM) load at 4.2 K. Tests were performed under a background magnetic field up to 18.5 T, resulting in a peak magnetic field on the innermost layer turns of around 21.1 T at an operating current of 6.3 kA. The effects of operation with cyclic EM loads were tested by repeated current ramps to around 95% of the critical current. Moreover, the V – I characteristics were measured at 77 K and the self-field, to check the effects from warm-up and cool-down (WUCD) cycles between room temperature and 77 K with liquid nitrogen. The results show no obvious degradation after dozens of high-current test cycles in background fields ranging from 10 T to 18.5 T. The insert solenoid demonstrates the stable operation of the REBCO sub-size cable for CICC with EM loads of about 90 kN m −1 and WUCD cycles between room temperature and 77 K. These promising results indicate the potential of this technology for further applicationsin particular, for full-size CICC for high-performance fusion magnets.