Study on neutron irradiation effect of superconductors and installation of 15.5 T magnet in hot laboratory at IMR in Tohoku University

A fusion reactor will yield a lot of high energy neutrons, and some of them will stream out of a plasma vacuum vessel and penetrate a blanket system and reach superconducting magnets which provide high magnetic field to confine high energy ionized particles. Under the neutron irradiation, the magnet materials will be activated and the properties will change. In this study, a research network on study of the irradiation effects is introduced and some data recently obtained are presented. By neutron irradiation, the critical current of the Nb3Sn wire increased and the critical field did not change. The organic insulation materials were degraded at neutron fluence of 1 x 1022 n/m2. In addition, the outline of an installation plan of 15.5 T superconducting magnet into radiation control area is described and study issues are explained. The project is undergoing as a program of Nuclear Basic Infrastructure Strategic Study Initiative.