一、引言在反应堆芯部添加少量可燃毒物,不仅能加深燃耗,延长寿期;还能起到展平功率分布、减少控制棒及其驱动机构数量的作用。硼和钆都是良好的可燃毒物。它们都有很高的中子俘获截面,在俘获中子以后转变成小截面的稳定元素。因此,硼元素早已广泛地用作可燃毒物了。此外,钆元素还有良好的温度效应和燃耗充分等特性。对钆的研究 I. INTRODUCTION Adding a small amount of flammable poison to the reactor core not only deepens the burnup and prolongs the lifetime, but also helps to flatten the power distribution and reduce the number of control rods and driving mechanisms. Boron and gadolinium are good flammable poison. They all have high neutron capture cross sections that transform into small cross-section stable elements after capturing neutrons. Therefore, boron has long been widely used as a burnable poison. In addition, gadolinium also has good temperature effects and burn-full features. Research on gadolinium