Nuclear technology and potential ripple effect of superconducting magnets for fusion power plant

In a fusion reactor plant, a neutral beam injector (NBI) will be operated for a long time, and it will allow neutron streaming from NBI ports to outside of the plasma vacuum vessel. This fact requires that the superconducting magnets develop nuclear technology to maintain high performance and to reduce activation of the magnet components. In this report, the background of the necessity and the elements of the nuclear technology of the superconducting magnets for fusion application are discussed, and some typical investigation results are presented. Examples include the Tc shift of about 0.6 K in RHQ Nb3Al wire after 14 MeV neutron irradiation of about 2 × 1020 n/m2 and no remarkable change in Tc in RHQ and annealed Nb3Al and Nb3Sn wires, the development of low activation superconducting wire, and the new design concepts to protect the magnets from the streaming. In addition, recent activities in high energy particle physics are introduced and the potential ripple effect of the technology of the superconducting magnets is described briefly.