堆芯跌落事故下水力缓冲性能分析研究

Buffering Effect Analysis for Secondary Supports in Reactor Vessel Internals under Assumption Accident of Core Drop

对采用"水力缓冲+机械缓冲"技术的反应堆堆内构件二次支承结构缓冲性能进行分析,研究假想堆芯跌落事故(吊篮断裂)下反应堆堆内构件二次支承结构对吊篮组件的水力缓冲作用机理。基于Fluent动网格技术对吊篮组件跌落过程进行数值模拟,分析不同竖直间隙、冷却剂温度及初始流速下吊篮组件跌落过程的运动规律;基于LS-DYNA非线性动力分析程序分析跌落末端的冲击过程,研究二次支承结构水力缓冲作用效果。分析显示,堆芯跌落事故下,水力缓冲可以吸收缓解大部分跌落冲击能量,与传统缓冲结构相比,缓冲效果更佳,确保了反应堆压力容器(RPV)的结构完整性和堆芯稳定性。

To research the buffering effect of secondary supports in reactor vessel internals under the assumption accident of core drop(core barrel broken down), a buffering effect analysis of secondary supports is performed, based on the technology of water buffering and mechanical buffering. In this paper, the process for core drop is numerically modeled, and the core barrel movement mechanism under different vertical gap, coolant temperature and initial flow rate is analyzed based on Fluent. The impact process in the end of core drop is analyzed and the water buffering effect of the secondary support is studied based on LS-DYNA. The analysis results show that, using the technology of water buffering and mechanical buffering, the secondary supports can bearing the impact energy of the core drop, and the coolant can buffer most of the impact energy. The buffering effect of secondary supports in this paper is better than that of the traditional support structure, to ensure the integrity of the reactor pressure vessel(RPV).