Development of LaYO3 as a reaction-preventing material for metal fuel casting

This study investigates the potential of LaYO3 as a crucible material to prevent interactions between a U-10 wt% Zr melt containing highly reactive lanthanide elements and the substrate during casting. The stability of LaYO3 phases at casting temperature was evaluated based on reaction phenomenon, chemical and physical properties. Sintered pellets were fabricated using both La2O3 and Y2O3 powders and structure of bodies were investigated using X-ray diffraction. The reaction behaviors of UZr and U-Zr-RE melts with the LaYO3 and Y2O3 specimens were investigated using sessile drop method, and microstructures of the interfaces were studied using scanning electron microscopy and energy-dispersive X-ray spectroscopy. The thermodynamics of LaYO3 were analyzed to demonstrate its reaction-preventing effect. Results indicate that LaYO3 is more effective than Y2O3 in reducing the interaction between the substrate and the melt, and it significantly decreases the partial reduction of the reaction-preventing layer. These findings suggest that LaYO3 has the potential to be an effective crucible material for preventing interactions during casting. •A novel reaction-preventing material, LaYO3, has been developed for metal fuel casting applications.•LaYO3 was fabricated using sintering, resulting in a perovskite structure that prevents reactions during casting.•The LaYO3 enhanced the reaction-preventing effect more than the conventional material Y2O3.•The interaction behavior of both LaYO3 and Y2O3 was investigated using sessile drop tests and thermodynamic analysis.