烧结成型的UO2陶瓷燃料微观力学性能研究进展

作为反应堆的核心，UO2陶瓷燃料的力学性能与其安全可靠性、经济性紧密相关，一直是国内外的研究热点。当前学者已针对未辐照UO2燃料开展了大量研究，结果表明，UO2燃料的力学性能受晶粒尺寸、晶体取向、气孔率、O/U比、应变量、掺杂相类型及掺杂量等多种因素影响，并且还与测试温度密切相关，但这些影响因素对其力学性能的耦合作用尚不清楚。近年来国外研究者还通过先进的纳米力学测试技术，对辐照后的UO2陶瓷燃料进行了研究，为其设计制备和寿期内性能预测提供了关键数据支撑。首先介绍了UO2微观力学性能研究手段，并对未辐照以及辐照后UO2陶瓷燃料微观力学性能研究进展进行了综述，总结了现有的不足并提出了后续研究的建议:在服役温度以及事故温度下对不同燃耗的UO2燃料开展研究，获得实际工况和事故工况下UO2燃料微观力学性能随燃耗的演变规律及机制，为燃料元件持续优化改进提供支撑。

Research Progress on Micromechanical Properties of Sintered UO2 Ceramic Fuel

As the core of the reactor, the mechanical performance of UO2 ceramic fuel is closely related to its safety, reliability and economy, and has been a hot research topic at home and abroad. Numerous studies have been conducted by previous scholars on unirradiated UO2 fuels. The results show that the mechanical properties of UO2 fuels are affected by various factors such as grain size, crystal orientation, porosity, O/U ratio, strain, doping phase type and doping amount, and are also closely related to the test temperature, but the coupling effect of these influencing factors on their mechanical properties is not clear. In recent years, foreign researchers have also conducted studies on irradiated UO2 ceramic fuels through advanced nanomechanical testing techniques, providing key data to support their design, preparation and lifetime performance prediction. Firstly, this paper introduces the research methods of UO2 micromechanical properties, and reviews the progress of micromechanical properties of unirradiated and irradiated UO2 ceramic fuels, summarizes the existing shortcomings, and proposes recommendations for follow-up research:research on UO2 fuels with different burnups under service temperature and accident temperature, and obtain the evolution law and mechanism of UO2 fuel micromechanical properties with burnup under actual working conditions and accident conditions, to provide support for the continuous optimization and improvement of fuel elements.