New Refractory-Multiple Principal Element Alloy (R-MPEA) coatings and components for molten-salt nuclear reactor system valves and pumps

The Department of Energy (DOE) seeks the application of revolutionary cross-cutting materials science and manufacturing technologies to advance the state-of-the-art in nuclear fission reactors. These advancements in nuclear reactor technology will enhance performance and reduce cost of new construction and major component replacements, resulting in the deployment of clean, affordable, and long-life domestic energy sources. Precision Materials Engineering LLC (PRIME) propose to leverage Ames National Laboratory groundbreaking research & development (R&D) in Refractory-Multiple Principal Element Alloy (R-MPEA) modeling, manufacturing, and testing for nuclear-system component (e.g., valves and pumps) applications. This unique material family, consisting of non-equiatomic niobium (Nb)-tantalum (Ta)-vanadium (V)-titanium (Ti), was developed using Ames’s fundamental density-functional theory (DFT)-based alloy design framework. Alloy design predictions were validated in the form of a castable single-phase, refractory alloy exhibiting an unprecedented combination of material properties: 1) melting temperature of about 2250?C, 2) tensile yield strength of over 1 GPa (145 ksi), 3) moderate modulus of about 113 GPa (16.4 msi), 4) room-temperature tensile ductility of >25%, and 5) cold-rolling deformation up to a 60% thickness reduction without cracking. This unique property set suggests this R-MPEA material could be formed into MSR flow-valve components, e.g., shafts, seals, and bushings/seats for use in extreme environments like molten-salt nuclear-fission reactors (MSRs). In Phase I, PRIME will obtain material from Ames for: 1) Molten-salt screening exposures at Idaho National Laboratory, 2) Feasibility demonstration of R-MPEA sputter-coating deposition onto valve structural materials, 3) Elevatedtemperature oxidation exposure to examine the generation of beneficial, non-galling oxides, 4) Roomtemperature galling tests on as-cast, sputter-coated, and oxidized R-MPEA material, and 5) Characterization of sputter-coated material including scratch adhesion and indentation toughness. In addition, we will investigate with a major valve manufacturer, e.g., Flowserve, potential applications for this material. A commercialization plan will be developed to define the coating and component opportunities for the RMPEA material in fission and fusion energy systems, as well as for aeronautic and aerospace systems (e.g., turbine engine blades, blisks), and waste-recycling systems (e.g., biomass burners / incinerators and superheater tubes).