The Comprehensive Research Facility for Fusion Technology (CRAFT) project has been launched in 2019, for developing the essential engineering technologies for Chinese Fusion Engineering Testing Reactor (CFETR). Within this project, a full-size toroidal field (TF) coil will be built as the prototype coil for CFETR. Based on design of CFETR magnet system, the TF coil will operate at 95.6 kA in a peak field of 14.5 T. The high-Jc Nb3Sn strand is taken into consideration due to the critical current density of ITER-grade Nb3Sn is too low at 14.5 T. Considering that it will be the first time to apply the high-Jc Nb3Sn strand in the large-scale cable-in-conduit conductor (CICC) for fusion magnet, a conductor sample made of high-Jc Nb3Sn strand with short twist pitch (STP) cable pattern was manufactured in ASIPP and tested in SULTAN facility, to investigate the feasibility. The test campaign focuses on the impact of cyclic electromagnetic (EM) loading and warm-up cool-down (WUCD) to the performance of the conductor, the strain distribution of the conductor before and after EM cycles was measured by inductive method to make a deeper insight of the conductor performance evolution. AC losses tests have also been carried out, providing relevant information for further coil design.
中国聚变工程测试反应堆（CFETR）的关键工程技术研究项目（CRAFT）已于2019年启动，旨在开发CFETR所需的关键工程技术。在该项目框架内，将建造一个全尺寸的环向场（TF）线圈作为CFETR的原型线圈。根据CFETR磁体系统的设计，该TF线圈将在14.5 T的峰值磁场下以95.6 kA的电流运行。由于ITER级Nb3Sn超导股线在14.5 T下的临界电流密度不足，因此考虑采用高Jc Nb3Sn超导股线。考虑到这是高Jc Nb3Sn超导股线首次应用于聚变磁体的大型电缆导体（CICC），在ASIPP制造了一个采用短节距（STP）电缆结构的导体样品，并在SULTAN装置上进行了测试，以评估其可行性。测试重点研究了循环电磁（EM）载荷和冷热循环（WUCD）对导体性能的影响，并通过感应法测量了EM循环前后导体的应变分布，以深入了解导体性能的演变规律。此外，还进行了交流损耗测试，为后续线圈设计提供了相关信息。