Nondestructive evaluation of neutron irradiation damage on type 316 stainless steel by measurement of magnetic properties

The relationships between neutron irradiation damage parameters, dose and He content, and the magnetic properties evaluated from the magnetic curves measured by a new developed vibrating sample magnetometer were investigated on type 316 stainless steel. A fast neutron reactor, JOYO, and a thermal neutron reactor, JRR-3, were used for irradiation. In addition to irradiation in each of the reactors, irradiations using the both of them, the coupling irradiation, were also conducted in this study. Irradiation in different reactor and especially the coupling irradiation enabled us to evaluate the effects of dose and He content to the magnetic properties individually in a wide irradiation damage range hardly obtained by irradiation in only one reactor. As the result, it was revealed that the magnetic parameters, especially magnetization at 0.5/μ _{0} A/m and coercive force, have close relationships with dose. Furthermore, the comparison with the result of tensile test showed that these magnetic properties are related to irradiation hardening. On the other hand, any magnetic properties investigated in this study are not dependent on He content. These results show the possibility of nondestructive evaluation of dose and irradiation hardening based on the magnetic properties.