气泡相互作用对燃料颗粒应力分布的影响

本工作建立了受气泡内压作用的双气泡UO2模型，利用有限元方法得到燃料颗粒受气泡内压作用、不同气泡间距条件下的燃料颗粒应力分布结果，并讨论了气泡间距、气泡半径和气泡内压对气泡之间相互作用的影响。研究结果表明，受气泡相互作用的影响，燃料颗粒内部产生了应力集中，应力集中倍率与气泡间距和气泡半径的比值（距径比）有关，与气泡内压无关。当距径比等于1时，应力集中倍率约为未考虑气泡相互作用影响时的2倍。当气泡尺寸不同时，应力集中主要发生在靠近小气泡的燃料基体处。

Effect on Stress Distribution of Fuel Particle Under Interaction of Bubbles

The UO₂ dual bubbles model under bubble internal pressure was proposed, and the stress distribution of fuel particles under different intra-bubble distances was calculated by using the finite element method. The effects of intra-bubble distance, bubble radius and bubble internal pressure on the interaction of bubbles were discussed. The results show that when the interaction of bubbles is considered, stress concentration occurs and locates at the fuel particles between bubbles. The rate of stress concentration is related to the ratio of intra-bubble spacing to bubble radius (spacing radius ratio, SRR) but unrelated to the bubble internal pressure. When SRR equals 1, the stress concentration rate is about twice that when the interactions of bubbles are ignored. When the sizes of bubbles are different, the stress concentration occurs primarily at the fuel near the small bubbles.