轻水堆含钆燃料棒稳态辐照行为分析

摘要

In the latest design of PWR fuel assemblies ,urania‐gadolinia (UO2‐Gd2 O3 ) fuel is widely adopted as burnable poison to control the initial reactivity and flatten the power profile in reactor .And the performance of gadolinia doped fuel rods is different from ordinary fuel rods .In this study ,the performance of gadolinia doped fuel rods , which were tested in BR3 reactor ,was analyzed by using the fuel performance code FRAPCON‐3.5 .The results show that the calculated values agree with the experiment values .In addition ,the self‐shielding effect of gadolinia doped fuel rods is enhanced at the initial period of radiation ,which has a significant influence on the radial power distribution of fuel rods .Besides ,if the average power density is same ,the thermal conductivity of gadolinia doped fuel is lower which results in higher pellet temperature . The fission gas release fraction and the deformations of fuel and cladding are different with the weight fraction of gadolinia in fuel .%国内外的压水堆燃料组件最新设计中，广泛采用钆燃料（UO2‐Gd2 O3）作为可燃毒物来控制初始反应性和展平堆芯功率分布。钆燃料棒的性能与普通燃料棒存在较大差异，本文利用燃料元件性能分析程序FRAPCON‐3.5对BR3堆内含钆燃料棒性能进行计算，并与实验测量值进行比较。结果表明：FRAPCON‐3.5对含钆燃料棒的计算结果与实验测量值符合较好；含钆燃料棒在辐照初期强化了燃料棒自屏效应，对燃料的径向功率分布影响显著；在平均功率密度相同的情况下，燃料中加入钆会导致热导率降低，芯块温度升高；钆含量不同，裂变气体释放及燃料和包壳的变形略有差异。