This work describes the microstructural evolution of prototypical monolithic U-Mo fuel plates analyzed via scanning electron microscopy and electron backscattered diffraction (EBSD). The understanding of the microstructural and textural evolution of nuclear fuel from as-fabricated to post-irradiation is important in assessing changes in material properties during irradiation. In our work it was observed that the typical fabrication techniques applied in U-10Mo monolithic fuel plates develop features associated with a cold-rolled body-centered cubic (bcc) texture and development of α and γ fiber (parallel to the rolling and normal direction). After irradiation, a loss of the fabrication-induced preferred orientation was observed with an increased spread of grain-boundary misorientation as burnup increases. Grain subdivision was observed in the irradiated samples with the formation of submicron grains (200–500 nm). Evidence for polygonization as the mechanism leading to grain subdivision was detected. This has been observed for the first time for U-Mo monolithic fuel via EBSD and has been associated to formation of low-angle grain boundaries (<15 degrees) at the site of the submicron grains. Such analyses of the microstructural and textural evolution of fuel (from fabrication to after irradiation) have the potential to help develop and validate microstructural physics-based models and provide a key feedback loop to further understand the interplay between fabrication processes and fuel performance.

这项工作描述了通过扫描电子显微镜和电子背散射衍射（EBSD）分析的典型整体式U-Mo燃料板的微观结构演变。对核燃料从预制辐射到辐射后的微观结构和组织演变的理解，对于评估辐射过程中材料特性的变化非常重要。在我们的工作中，观察到在U-10Mo整体式燃料板上使用的典型制造技术具有与冷轧的体心立方（bcc）织构以及α和γ纤维的发展相关的特征（平行于轧制方向和法线方向） ）。辐照后，随着燃耗的增加，观察到了制造诱导的优选取向的损失，晶界取向错误的扩散也增加了。在被辐照的样品中观察到晶粒细分，形成亚微米晶粒（200–500 nm）。检测到多边形化作为导致晶粒细分的机制的证据。这是首次通过EBSD对U-Mo整体式燃料进行观察，并与在亚微米晶粒处形成低角度晶界（<15度）有关。燃料的微观结构和组织演变（从制造到辐照后）的这种分析有可能帮助开发和验证基于微观结构物理学的模型，并提供关键的反馈回路，以进一步了解制造过程与燃料性能之间的相互作用。检测到多边形化作为导致晶粒细分的机制的证据。这是首次通过EBSD对U-Mo整体式燃料进行观察，并与在亚微米晶粒处形成低角度晶界（<15度）有关。燃料的微观结构和组织演变（从制造到辐照后）的这种分析有可能帮助开发和验证基于微观结构物理学的模型，并提供关键的反馈回路，以进一步了解制造过程与燃料性能之间的相互作用。检测到多边形化作为导致晶粒细分的机制的证据。这是首次通过EBSD对U-Mo整体式燃料进行观察，并与在亚微米晶粒处形成低角度晶界（<15度）有关。燃料的微观结构和组织演变（从制造到辐照后）的这种分析有可能帮助开发和验证基于微观结构物理学的模型，并提供关键的反馈回路，以进一步了解制造过程与燃料性能之间的相互作用。