Neutron Radiation-Induced Demagnetization Effect of Sm(Co_0.82，Fe_0.1，Cu_0.06，Zr_0.02)_7.2 Permanent Magnetic Materials

The permanent magnet applied in reactor is in the adverse circumstances of neutron radiation-induced demagnetization, and the functions of permanent magnet will be influenced by irradiation. To investigate the performance of permanent magnetic materials under neutron radiation, the activation calculations of Sm(Co_0.82，Fe_0.1，Cu_0.06，Zr_0.02)_7.2 permanent magnet after 2 a neutron radiation were carried out with the European activation system EASY-2007. Then the magnetic attenuation can be predicted by analyzing the changes of elemental composition. The result shows that Fe content changes little after neutron radiation, but Sm content decreases significantly, which makes coercivity decrease seriously.