Japan’s Kyoto Fusioneering (KF) and Fujikura have completed Phase One of their joint R&D project on high-temperature superconducting (HTS) magnets. The project was awarded by the UK Atomic Energy Authority’s (UKAEA), as part of its STEP (Spherical Tokamak for Energy Production) programme. The programme is led by its wholly owned subsidiary, UK Industrial Fusion Solutions (UKIFS), which was established to commercialise fusion energy.
The project aims to improve HTS magnet design, with a focus on understanding and minimising AC loss – a key challenge in developing high-performing HTS coils for fusion applications. The insights gained from a wide range of experimental data are vital for the successful design, analysis, and manufacturing of the HTS magnets that will be incorporated in UKIFS’s STEP programme.
The project kicked off with the design and fabrication of prototype coils to collect critical performance data. Working closely with UKIFS, the team identified key specifications, structural parameters, and testing protocols – ensuring alignment with the physical properties and geometries relevant to HTS magnet systems. Fujikura leveraged its advanced manufacturing capabilities to produce seven high-quality prototype coils with distinct internal structures.
In parallel, a custom-built testing environment was developed to match the specific requirements of the prototype coils. Rigorous tests conducted at cryogenic temperatures revealed that the coils’ current-carrying performance, the current-voltage characteristics of the superconductivity, closely matched KF’s simulation predictions, validating the consistency of Fujikura’s HTS wire performance.
HTS wire can now be fabricated into a variety of test coil structures without compromising its superconducting properties. The testing also produced reliable data on AC losses, reinforcing the strength of the overall design and the integrity of the experimental process. The project concluded with the successful delivery of core performance data to UKIFS, marking a strong finish to Phase One.
