Investigation on radiation interactions with some quenched alloys used in nuclear reactors

This study presents the investigation of the radiation interaction properties for SS304 and Incoloy 800H alloys, which are widely used in PWRs and HTGRs. First of all, theoretical and MC simulation evaluations are performed, then experiments are conducted for further analysis. The findings indicate no significant difference in mass attenuation coefficients (MAC) and gamma-ray radiation protection efficiencies (RPE) between the two alloys. Additionally, both SS304 and Incoloy 800H exhibit similar neutron shielding capabilities, with comparable effective removal cross-sections and numbers of transmitted neutrons at different neutron energies (0.025 eV, 100 eV and 4.5 MeV). The study also examines secondary radiation generated by neutron interactions. The impact of thermal treatment (300 °C, 500 °C, 700 °C and 1000 °C) and cooling approaches (quenching and self-cooling) on these alloys were further experimentally examined. Notably, thermal treatment changes the MAC values, particularly at 1000 °C, with SS304 showing a more distinct change than Incoloy 800H. Besides, quenched samples have higher MAC values compared to self-cooled samples, especially at 1000 °C. However, the microhardness values remained largely unaffected by heat treatment, except at 1000 °C, where both alloys exhibited reduced microhardness. The study underscores that there is no significant difference in microhardness between quenching and self-cooling techniques. These results provide valuable insights for enhancing the safety and efficiency of radiation shielding materials in nuclear reactors.