Current status of studies on point defect structures of uranium carbide nuclear fuels

Abstract Background: Uranium carbide has attracted extensive attention as a potential candidate for the fourth generation nuclear fuel, and it is crucial to understand its structures, bulk properties and defect formation to learn the impact of fission products on the performance of the fuels as the fission reaction proceeds for the purpose of proper and safety operation. Purpose: This study aims to help clarify the serving behaviors of uranium carbide as well as provide valuable clues for fuel designers. Methods: Irradiation in experiments and first-principles in theory are mostly used in the literature to analyze the point defect structures of uranium carbide nuclear fuels. Results: The theoretical and experimental studies for uranium carbides (UC, UC₂ and U₂C₃) are reviewed, chemical and mechanical properties of defective structures are analyzed emphatically and recommendations for further studies are provided. Conclusion: All these provide new insight into the properties of carbide nuclear fuels. (authors)