This work describes the microstructural evolution of textured alpha uranium (α-U) specimens under different reactor transients achieving very low burn-up. The understanding of the behavior of this single phase will provide important information to further the material knowledge of metallic fuels (e.g. U-Pu-Zr, U-10Zr). Such alloys are of interest for their application in advanced reactor concepts. In metallic fuels α-U is, indeed, a relevant phase. Moreover, data on fuel behavior during early-stage irradiation are generally lacking and are important to validate and develop modelling and simulation tools. Characterization of grain boundaries, texture evolution, and phase transformation were obtained through scanning electron microscopy coupled with electron backscattered diffractometry and transmission electron microscopy .The data obtained indicates that phase transformation and microstructural change (e.g. recrystallization/grain growth) can occur during rapid transient even at low burn up. It is likely that the residual strain in the as-fabricated α-U specimens and the thermal strain introduced by reactor transients played an important role in the recrystallization of the α-U phase, as well as retaining the β-U phase at room temperature.

这项工作描述了在不同的反应堆瞬态下，达到极低燃耗的织构化α铀（α-U）标本的微观结构演变。对单相行为的理解将为进一步了解金属燃料（例如U-Pu-Zr，U-10Zr）的材料知识提供重要信息。此类合金因其在高级反应堆概念中的应用而受到关注。在金属燃料中，α-U实际上是一个相关相。而且，通常缺乏早期辐射期间的燃料行为数据，这对于验证和开发建模和仿真工具很重要。通过扫描电子显微镜，电子背散射衍射和透射电子显微镜对晶界，织构演化和相变进行了表征。获得的数据表明，即使在低燃耗下，在快速瞬变过程中也可能发生相变和微观结构变化（例如，重结晶/晶粒生长）。制备后的α-U标本中的残余应变和反应堆瞬态引入的热应变可能在α-U相的重结晶以及将β-U相保持在室温下发挥了重要作用。