高温熔融物与金属堆腔相互作用实验研究

为掌握船用反应堆严重事故工况下压力容器失效初期堆芯熔融物热冲击对金属堆腔的破坏效应，开展了堆芯熔融物与金属堆腔相互作用机理实验。根据相似准则设计缩比金属堆腔实验装置，利用已有高温熔融物实验平台制备2 700 ℃高温氧化锆熔融物，通过特制卸料机构将高温熔融物卸料到实验段，对热冲击下实验段温度和变形响应特性及主要影响因素进行了研究。实验结果表明，高温熔融物进入金属堆腔初期，热冲击导致的金属堆腔最高温度为601 ℃，最大塑性变形量为0.44 mm，高温熔融物未导致金属堆腔热失效及断裂失效，金属堆腔实验段能保持完整。由于船用反应堆金属堆腔材料、结构和外部冷却条件更有利于保持金属堆腔完整性，基于实验结果推断，严重事故下压力容器下封头失效初期热冲击导致金属堆腔失效的风险较低。

Experimental Study on Interaction between High Temperature Molten Oxide and Metallic Cavity

An experimental study was performed to understand the interaction mechanism and the thermal shock effect of the molten oxide and metallic cavity, when the reactor pressure vessel failure occurred in the core molten accident for the marine nuclear propulsion reactor. In this work, a scaled metallic cavity test section was designed on the basis of similarity criterion for the heat transfer progress, the zirconium oxide was melted at around 2 700 ℃ by using the cold crucible technique, and then the molten zirconium oxide was discharged into the metallic cavity. The temperature and deformation response characteristics and main influencing factors of the metallic cavity under thermal shock were obtained and studied. The experimental results show that the peak temperature of the metallic cavity caused by thermal shock is 601 ℃ and the maximum plastic deformation is 0.44 mm, neither thermal failure nor structural failure occurrs, and the integrity of the metallic cavity can be maintained in the early stage. The experimental results infer that the material, the structure and the coolant heat transfer conditions for the marine nuclear propulsion reactor are more conducive to maintaining the integrity of the metallic cavity, and the failure of the metallic cavity in the early stage is a very low probability event.