Novel ternary U–N–O compounds: Potential candidates for accident tolerant fuels

The UN–UO₂ composite fuel has attracted much attention due to its higher oxidation resistance compared to UN and enhanced thermal conductivity and uranium density compared to traditional UO₂. However, the interaction between UO₂ and UN leads to undesired α-U₂N₃, which seriously affects the service performance. Herein, a high-throughput computational method was employed to systematically screen the entire U–N–O ternary system for potential accident-tolerant fuels. Five novel stable ternary U–N–O compounds were identified. A comprehensive exploration of the electronic, mechanical, and thermal properties of compounds within the U–N–O system unveiled a discernible composition-structure-property relationship. Through comprehensive analysis, P4/nmm-UNO emerged as a highly promising candidate for accident tolerant fuel, boasting superior stability, mechanical strength, melting point, thermal conductivity, and excellent corrosion resistance. Our study provides valuable insights for the further development of these potential accident tolerant fuels.