Critical currents in REBaCuO superconducting tapes in response to neutron irradiation

Electromagnetic performance of superconducting REBaCuO tapes from several manufacturers was investigated in response to neutron irradiation. The aim was to test the feasibility of using these tapes for wiring high-T-c superconducting magnets for fusion reactors. Magnetic induction was employed to determine critical currents. In non-irradiated SuNAM, SuperOx, and SuperPower tapes without additional pinning centers, the normalized pinning force density as a function of the normalized magnetic field, h, exhibited the commonly observed single peak at about h = 0.2 in the whole temperature range 10 K-80 K. In the non-irradiated AP (advanced pinning) SuperPower tapes this dependence developed an extraordinary shape below 70 K. This feature changed with increasing neutron fluence. The effect of neutron irradiation on critical currents was found to be rather complex. In all samples, neutron irradiation by a total fluence of 8.03x10(22) m(-2) caused a critical current degradation at low magnetic fields in the temperature range 10 K-77 K. At high magnetic fields, the effect varied depending on the tape's initial pinning structure, temperature, and neutron fluence. At 77 K, the current decreased and the irreversibility field was reduced in all the samples. At intermediate temperatures the critical current nearly did not change, while at temperatures below 30 K the critical current increased.