Dry storage and ultimate disposal of irradiated nuclear fuel in a power reactor are important problems to address in the nuclear industries. These problems involve the volume oxidation phenomenon that makes difficult the investigation of oxidation process of the uranium dioxide pellets in the air. In this study, a mathematical model is developed for this phenomenon at temperatures below 727 K, which simulates the diffusion of oxygen within the pores of the pellet and oxidation of the pellet body, simultaneously. Coupled equations of heat and mass transfers within this pellet with variation of its properties are solved for this simulation. Approving the predictions of this model using the experimental data approves the accuracy of the presented model and also the numerical calculations.

动力反应堆中辐照核燃料的干式储存和最终处置是核工业需要解决的重要问题。这些问题涉及体积氧化现象，这使得二氧化铀球团在空气中的氧化过程的研究变得困难。在这项研究中，针对低于 727 K 的温度下的这种现象开发了一个数学模型，该模型同时模拟了颗粒孔隙内的氧气扩散和颗粒主体的氧化。在该模拟中求解了该颗粒内的热和质量传递及其性质变化的耦合方程。使用实验数据批准该模型的预测证实了所提出模型的准确性以及数值计算。