Abstract UO2 single crystals with (100), (110) and (111) oriented faces were dissolved in 2 mol.L−1 HNO3 at room temperature. The evolution of the topography of the surface was monitored and reliable dissolution rates corresponding to the three crystallographic orientations were determined under controlled hydrodynamic and chemical conditions. The dissolution tests of UO2 polished single crystals showed two different kinetic steps. During the first uncatalysed kinetic regime, the enhanced reactivity of the surface at defect sites was demonstrated. The second kinetic step was attributed to a catalysed dissolution mechanism involving species produced at the solid/solution interface during the first step.

中文翻译：

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表面取向对二氧化铀单晶在硝酸中溶解速率和表面动力学的影响

摘要 在室温下将具有 (100)、(110) 和 (111) 取向面的 UO2 单晶溶解在 2 mol.L-1 HNO3 中。监测表面形貌的演变，并在受控的流体动力学和化学条件下确定对应于三种晶体取向的可靠溶解速率。UO2 抛光单晶的溶解测试显示了两个不同的动力学步骤。在第一个未催化的动力学状态期间，证明了缺陷位点表面的增强反应性。第二个动力学步骤归因于催化溶解机制，涉及在第一步期间在固/溶液界面产生的物质。