The Corrosion Behavior of Carbon Steel Materials Used at Nuclear Power Plants During Deactivation and Decommissioning Processes

This study is focused on the corrosion behavior of carbon steel A106 B in a static water environment, which simulated the decommissioning transition phase of BWR power plants. When the autoclave was filled with stagnant water, the corrosion rates of carbon steel pipe for the cold-drawn and hot-rolled samples were 23 μm/year and 19 μm/year, respectively. When the autoclave was not completely filled with water, leaving the samples fully submerged, the corrosion rate for the hot-rolled sample increased to 88 μm/year. In an autoclave with periodic water flow, the corrosion rate for the cold-drawn sample decreased to 11 μm/year. When the autoclave was not completely filled with water, the sample positioned at the air–water interface exhibited the highest corrosion rate of approximately 102 μm/year. These results indicate that the influence of ion concentration on the corrosion rate outweighed that of dissolved oxygen. Sufficient oxygen concentration facilitated the formation of FeOOH or Fe2O3, while an oxygen-deficient environment favored the formation of Fe3O4.