Structural Components with Corrosion Resistant Surface Layers for Advanced Nuclear Reactor Systems

Advanced high temperature nuclear reactor systems that utilize liquid coolants such as molten fluorides require structural components that are also corrosion resistant to the coolant. The current structural components approved for use in ASME Code Sec III Div 5 have insufficient corrosion resistance for long lifetimes. This problem will be addressed by the incorporation of thick, corrosion resistant surface layers using a unique hot pressing technique in which pressure can be applied with one or more metallic components in the molten state. This is enabling for producing highly adherent layers with no to minimal residual porosity. In Phase I, screening studies will be performed including corrosion testing in molten fluoride salts to identify preferred surface layer compositions that will be incorporated on stainless steel and nickel superalloys and subjected to longer term corrosion testing. Assessment of the samples will involve weight measurements, microstructural analyses with elemental mapping, and mechanical property testing including after thermal cycling. In addition to the nuclear applications, the coated materials developed in this program could be commercialized for concentrated solar cell systems, supercritical carbon dioxide systems, and high temperature, oxidation resistant components for aerospace, defense, and industrial applications.