弥散燃料颗粒裂纹起源的有限元模拟分析

通过建立含多气泡的燃料颗粒模型,采用有限元方法分析了燃料颗粒在裂变气体气泡内压作用下的应力分布,统计了燃料颗粒内部气泡位置对气泡内壁处的最大拉应力的影响,并结合实验结果探寻了弥散燃料颗粒在辐照后退火时的裂纹起源。结果表明:当弥散燃料颗粒内部含有多个裂变气体气泡时,受气泡内压作用,气泡内壁径向应力为压应力,环向应力为拉应力;气泡位置距燃料颗粒心部越远,气泡内壁处的最大环向拉应力越大;表层气泡的最大环向拉应力远大于心部气泡的;燃料颗粒裂纹起源于表层气泡内壁。

Analysis of Finite Element Simulation of Crack Initiation in Dispersion Fuel Particle

With the finite element method, the mutli-bubble fuel particle model was established and the stress distribution of the fuel particle was analyzed under the pressure of the fission gas bubbles (FGBs). The effect of the bubble location on the max tensile stress was summarized at the inner-border of bubble. And the crack initial location was found out while associated with the annealing result of the irradiated dispersion fuel particle. The results show that when the dispersion fuel particle suffers the pressure of the mutli-FGBs, the radius stress at the inner-border of bubble is the compress stress and the circular stress is the tensile stress. The farther the bubble location is relative to the center of the fuel particle, the bigger the max circular tensile stress is at the inner-border of bubble. The max circular tensile stress at the inner-border of the external bubble is much bigger than the central bubble’s. The crack of the dispersion fuel particle initiates at the inner-border of the external bubble.