On July 14, the independently developed CRAFT 100kA high-temperature superconducting (HTS) current lead, designed and manufactured by the Institute of Plasma Physics, Chinese Academy of Sciences (ASIPP), successfully passed extreme-condition performance testing, achieving a steady-state current-carrying capacity exceeding 100kA and setting a new world record.

High-temperature superconducting current leads serve as the "energy arteries" of superconducting magnet systems in fusion devices, integrating multiple disciplines including superconductivity, cryogenics, vacuum technology, mechanical engineering, measurement and control, and power supply. They perform the critical task of connecting room-temperature power sources to high-current superconducting magnets. Due to their unique position spanning from room temperature to ultra-low temperature (4.2K), the performance of current leads directly determines the operational efficiency and stability of the entire fusion device. As a key component of the Comprehensive Research Facility for Fusion Technology (CRAFT), a national major science and technology infrastructure project under China's "13th Five-Year Plan," the 100kA HTS current lead presented enormous design difficulty, complex manufacturing processes, stringent quality requirements, and extremely demanding test conditions. It must simultaneously satisfy three critical characteristics: high current capacity, low heat leak, and long loss-of-flow accident (LOFA) safety time.

Relying entirely on independent R&D, the project team achieved full domestic development across the entire chain: design, materials, fabrication, and testing. Test results show that the CRAFT 100kA HTS current lead requires only approximately 6.5g/s of 50K helium coolant flow, exhibits 0.4nΩ joint resistance at the 5K terminal, provides a 9-minute LOFA time, and offers a 27-second overheat safety margin. All performance indicators significantly exceed design requirements, establishing a new world record for steady-state 100kA operation.

Over the past decade, the Institute of Plasma Physics has fully mastered the complete set of core technologies for the design, R&D, manufacturing, and testing of ultra-high-current high-temperature superconducting current leads. It has successively delivered 13 pairs of 14kA HTS current leads for EAST, 66 HTS current leads of 10kA, 52kA, and 68kA for ITER, CRAFT 60kA and 100kA HTS current leads, and completed technology and product exports to Russia's National Research Center "Kurchatov Institute" (multiple batches of 12kA and 6kA), strong magnetic field facilities (16.5kA), and high-energy physics institutes (10kA).

The successful development of the 100kA high-temperature superconducting current lead lays a solid technical foundation for the construction and operation of large-scale fusion device superconducting magnet systems.