A potential candidate structural material for molten salt reactor: ODS nickel-based alloy

The commercialisation of molten salts reactors (MSRs) is hindered by the lack of structural materials capable of withstanding the corrosive environment therein. To address this problem, we herein prepared 1 wt% Y2O3 dispersion-strengthened NiMo-based alloys using powder metallurgy and evaluated their potential as structural materials for MSRs based on their mechanical properties, He swelling behaviour, and molten salt corrosion resistance. In view of the strengthening provided by homogenously dispersed Y2O3 particles, all NiMo-Y2O3 samples exhibited ultimate tensile strengths and yield strengths exceeding those of the Hastelloy N alloy, a state-of-the-art structural material for MSRs. Moreover, the volume fraction of He bubbles in the NiMo Y2O3 samples (similar to 0.3%) was lower than that in the Hastelloy N alloy (0.58%), which showed that the introduction of Y2O3 nanoparticles effectively inhibited He swelling. All NiMo-Y2O3 samples showed excellent resistance to molten salt corrosion (as reflected by the absence of obvious holes therein), thus holding great promise for the development of irradiation- and molten salt corrosion-resistant structural materials for high-temperature MSRs. (C) 2021 Published by Elsevier Ltd on behalf of Chinese Society for Metals.