Designing Nuclear Fuels with a Multi-Principal Element Alloying Approach

Previous research has shown that multi-principal element alloys (MPEAs) using chromium, molybdenum, niobium, tantalum, titanium, vanadium, and zirconium can form stable body-centered-cubic (BCC) structures across a large temperature region (25°C to 1000°C). This is the same crystal structure as γ-uranium (U), which desirable thermal irradiation behavior in previous alloy fuel research. It hypothesized then MPEA alloying approach be used produce BCC uranium-bearing retain its stability throughout anticipated operating regimes of power-producing reactors. Candidate elements were assessed Monte Carlo N-Particle (MCNP) analysis determine uranium densities necessary make an economically viable compared conventional forms. Following neutronic considerations, materials property databases empirical predictors compositions with high potential solid solution alloy. The final four MoNbTaU2, MoNbTiU2, NbTaTiU2, NbTaVU2, cast arc melting raw elemental foils chunks. Characterization fabricated included scanning electron microscopy, X-ray diffraction, energy dispersive spectroscopy, transmission microscopy. results showed two-phase system U-rich matrix phase surrounding refractory precipitates. U was found contain varying concentrations γ-U phase. These warrant further identify ideal for use advanced fuel.