We propose a model describing the HBS formation and the progressive intra-granular xenon depletion in UO2. The HBS formation is modeled employing the Kolmogorov-Johnson-Mehl-Avrami (KJMA) formalism for phase transformations, which has been fitted to experimental data on the restructured volumetric fraction as a function of the local effective burnup. To this end, we employed available experimental data and novel data extracted in this work. The HBS formation model is coupled to a description of the intra-granular fission gas behavior, allowing to estimate the evolution of the retained xenon in order to consistently compute fission gas retention and its effect on the fuel matrix swelling. The satisfactory agreement of the model predictions to experimental data and state-of-the-art models’ results, in terms of both xenon depletion and fuel matrix swelling as a function of the local burnup, paves the way to the inclusion of the model in fuel performance codes.

我们提出了一个模型，描述了HBS的形成和UO2中颗粒内氙的逐步消耗。HBS的形成采用Kolmogorov-Johnson-Mehl-Avrami（KJMA）形式主义进行相变建模，该形式已被拟合为关于重组体积分数作为局部有效燃耗函数的实验数据。为此，我们采用了可得的实验数据和这项工作中提取的新颖数据。HBS形成模型与颗粒内裂变气体行为的描述相结合，可以估算保留的氙的演变，以便一致地计算裂变气体的保留及其对燃料基体膨胀的影响。模型预测与实验数据和最新模型结果的令人满意的一致性，