RESEARCH TRENDS ON MICRO AND NANO-SCALE MATERIALS DEGRADATION IN NUCLEAR POWER PLANT

The recent research status of materials degradation in nuclear power plant (NPP) has been analyzed. The main research progresses include: kinetics of corrosion electrochemistry in high temperature pressurised water, preferential intergranular oxidation and the degradation of grain boundary strength, special grain boundary optimized materials corrosion resistance, tight crack of stress corrosion cracking, nano-scale atom cluster formation and effects. The research trends and key problems have been proposed, such as kinetics of corrosion electrochemistry in high temperature high pressure water, especially the effect of contaminating species on micro-process of corrosion; characterization of microstructure, physical, chemical and mechanical properties of surface film and near-surface materials, repassivation behavior of passive film, especially ion diffusion micro-process in the surface film arid near-surface materials; the effects of as-received surface and water chemistry on crack incubation and initiation; application of materials degradation mechanisms. In order to characterize the material environmental behavior, it is important to control the research and environment condition, and to develop new test methods in simulated NPP environment.