This paper describes the characteristics of magnetic Barkhausen noise (MBN) and permeability on neutron irradiated Fe and Fe-Cu alloys. The plates made of pure Fe and Fe-1 wt.% Cu alloys were prepared with and without cold-rolling. Those plates were irradiated by neutron with a total fluence of 1× 10
^{24}
n/m
^{2}
. Then MBN properties and impedance were measured using magnetic-yokes, a MBN sensor and a pick-up coil. The MBN rms voltage decreases with neutron irradiation, and the impedance increases after irradiation for cold-rolled specimen. On the other hand, the MBN properties and the impedance at lower frequency have no significant changes after irradiation for undeformed specimen. Contrary, the impedance at higher frequency for undeformed Fe-Cu alloy decreases after irradiation. The relations between those magnetic properties and the microstructure of irradiated materials were also discussed. Those results show the potential of nondestructive evaluation for neutron irradiation embrittlement in reactor pressure vessels.
