国产压水堆核电站40 GW•d/tU乏燃料棒金相检验

为评价国产燃料棒在较高燃耗水平下的辐照性能，在中国原子能科学研究院燃料与材料检验设施（303热室）对燃耗为40 GW•d/tU的国产压水堆核电站乏燃料棒进行了金相检验。检验内容包括芯块宏观与微观组织、包壳水侧腐蚀与氢化物分布、芯块-包壳相互作用状况等。金相检验结果表明：40 GW•d/tU燃耗下，芯块未发生明显的轮廓变化，气孔率为3.3%～5.8%，晶粒组织为等轴晶，平均晶粒尺寸为7.2 μm；Zr合金最大水侧氧化膜厚度为23 μm，氢化物分布和含量正常，最大氢含量约为150 μg/g，同时不同部位的包壳氢含量与水侧氧化膜厚度基本呈线性关系，水侧腐蚀处于正常水平；包壳内壁有局部轻微腐蚀，包壳与芯块之间存在间隙，未发生包壳与芯块相互作用情况。

Metallographic Test of Domestic PWR Nuclear Station Spent Fuel Rod of 40 GW•d/tU Burnup

In order to evaluate the radiation performance of domestic fuel rods at high burnup level, the metallographic test of a domestic pressurized-water reactor (PWR) nuclear station spent fuel rod with the burnup of 40 GW•d/tU was done in the Fuel and Material Examination Facility (303 hot cell) of China Institute of Atomic Energy (CIAE). The contents of the metallographic test include macro- and micro-structure examination of fuel pellets, waterside oxidation and hydride distribution of cladding, pellet-cladding interaction (PCI) and so on. The test and analysis results show that under the burnup of 40 GW•d/tU, the shape of the pellets is not changed obviously, the range of fuel porosity is 3.3%-5.8%, the grains of fuel are equiaxed crystal, and the average size of these grains is 7.2 μm. Waterside oxidation of the cladding is normal, and the maximum thickness of waterside oxide film is 23 μm. The content and distribution of hydride are normal, the maximum hydrogen content is 150 μg/g and the hydrogen content keeps a proportional relation with the thickness of waterside oxide film nearly. There is a slight localized corrosion in the inner wall of the cladding. The gap of pellets and cladding is existent and the PCI phenomenon is not found.