Neutron irradiation effects on the superconducting performance of REBCO coated conductors

Michael Eisterer

TU Wien, Atominstitut, Vienna, Austria

Tuesday, May 24, 2022


NW17-218 Hypbrid

PSFC Seminars

At present, coated conductors are the obvious choice for superconducting high-field fusion magnets. The toroidal field coils will suffer from neutron radiation that harms the superconductor. Neutrons introduce a large variety of defects that are beneficial by pinning vortices, thus enhancing the critical current. On the other hand, they suppress the transition temperature and superfluid density. The latter effects decrease the critical current. While the beneficial introduction of pinning centers dominates at low neutron fluences, the critical currents severely degrade at high fluences, which potentially limits the lifetime of fusion magnets. I will review our findings of neutron irradiation experiments in our in-house research reactor over the last 15 years. After having established the peak in critical current as a function of neutron fluence, we investigated the universality of this behavior followed by attempts to explain it by the competing effects of added pinning centers and reduced superfluid density. Recently, we started annealing experiments to devise mitigation strategies against the adverse effects of neutron radiation.