中文摘要：

基于合金中沉淀相粗化机制,建立了裂变气泡（FGB）长大的数学模型,以铀合金和陶瓷UO_2燃料为例,计算了在不同辐照温度和外压约束下气孔率、平均孔径随燃耗深度的变化。对UO_2燃料,当外压约束相同时,在700°C下的气孔率增长速度比400°C下的约快25%;外压约束对FGB的长大有一定抑制作用,但影响相对较小。由于金属燃料易于发生塑性变形,在同样的燃耗下,气孔率和平均孔径都显著大于陶瓷燃料。

英文摘要：

Based on the Ostwald ripening process, a mechanistic model for the fission gas bubble growth has been proposed in this paper. Taking U-Zr alloy and UO_2 ceramic fuel as samples, the variation of FGB porosity and mean bubble size with the burn-up at different irradiation temperature and external restraint have been investigated in detail. For ceramic UO_2, the porosity increase rate with the burn-up at 700°C is 25% faster than that at 400°C. The external restraint impedes the growth of FGB, but it is not very significant. The porosity and mean bubble size in U-Zr alloy for the same irradiation parameters are much greater than that in the ceramic UO_2 because the plastic deformation takes place very easy and quickly for U-Zr alloy during irradiation.