Feasibility analysis of partially insulated Nb3Sn EU DEMO toroidal field coil

Abstract The advent of no-insulation (NI) winding technique in high temperature superconducting magnets has marked a milestone, demonstrating enhanced thermal stability and mechanical integrity in various high-field applications. There have been reports on numerical and experimental results of the application of NI-class winding techniques to low temperature superconducting (LTS) magnets, showing improved thermal stability such as significant reduction of training, stable behavior during over-current operations, and even recovery after heater-fired quench as a result of current bypass near a hot spot. Thus, the NI approach might offer potential advantage to large scale LTS fusion magnet such as reduction of peak coil terminal voltage or decrease of the copper fraction within the conductor to achieve a more compact design. However, it is essential to firstly assess the potential risks ass…