严重事故下堆芯围板及吊篮熔融行为研究

Research on Melting Behavior of the Core Shroud and Barrel During a Severe Accident

为支撑堆芯熔融物压力容器内滞留有效性评估,采用计算流体动力学方法,建立了某先进压水堆堆芯辐射传热数值模型,对严重事故下围板及吊篮的熔融行为及其影响因素进行了研究。研究结果表明,在靠近堆芯燃料组件轴向功率分布因子峰值的节点,围板及吊篮的熔融行为较为显著;在同一节点处,围板的熔融并不是均衡发展的,最先熔穿的区域多发生在外围多个燃料组件交汇处,而吊篮的熔融则呈现出由内向外均衡扩展的变化趋势;压力容器外壁面的换热条件对堆芯围板及吊篮的熔融行为的影响并不显著,而燃料组件发射率的设置对堆芯围板及吊篮的熔融行为具有显著影响。可以为堆芯熔融物压力容器内滞留有效性评估提供技术支持。

In order to support the elevating of the validity of the In-Vessel Retention(IVR),the method of computational fluid dynamics(CFD)has been used to establish a numerical model of the core radiation heat transfer of an advanced PWR.The melting behavior of the shroud and barrel during a severe accident has been studied and some influencing facts have been analyzed.The results show that the melting of the shroud and barrel is most obvious at the node where the axial power factor is close to the peak value;the earliest melting through of the shroud occurs mostly where several fuel assemblies converge while the melting of the barrel spreads uniformly;the influence of the heat transfer outside the pressure vessel on the melting behavior of the shroud and barrel is not obvious while the influence of the emissivity of the fuel assembly is obvious.This research can offer technical support for the validity analysis of IVR.