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辐照过程中,燃料颗粒内部会产生裂变气体形成气孔,将对其热/力学性能造成显著影响。采用带屏蔽的金相显微镜(OM)、扫描电镜(SEM)和能谱仪(EDS)对辐照后U_3Si_2-Al弥散型燃料中U_3Si_2燃料颗粒的显微组织进行了观察,统计分析了燃料颗粒内气孔的形貌、尺寸及分布,获得气孔平均尺寸及孔隙率随燃耗深度的变化规律。结果表明,裂变密度在2.34×10~(27)~3.74×10~(27)m~(-3)范围内时,U_3Si_2-Al燃料颗粒中的裂变气体气孔的形貌未发生较大改变,均呈球状。而裂变气体气孔平均尺寸以及孔隙率均随着裂变密度的增加而增大,存在两个阶段:裂变密度在2.34×10~(27)~3.19×10~(27)m~(-3)范围内,稳态增长;裂变密度在3.19×10~(27)~3.74×10~(27)m~(-3)范围内,加速增长。
During the irradiation, fission gas is formed inside the fuel particles to form pores, which will have a significant impact on the thermal / mechanical properties. The microstructure of U_3Si_2 fuel particles in U_3Si_2-Al dispersed fuel after irradiation was observed by means of OM, SEM and EDS. The statistical analysis of the fuel particles The shape, size and distribution of the inner pores, the average pore size and porosity with the fuel consumption depth changes. The results show that the morphology of fission gas pores in U 3 Si 2 -Al fuel particles does not change significantly when the fission density is in the range of 2.34 × 10 27 to 3.74 × 10 27 m -3, All spherical. However, the average pore size and porosity of fission gas increase with the increase of fission density. There are two stages: the fission density is in the range of 2.34 × 10 ~ (27) ~ 3.19 × 10 ~ (27) m ~ (-3) And the steady state increased. The fission density increased rapidly in the range of 3.19 × 10 ~ (27) ~ 3.74 × 10 ~ (27) m ~ (-3).