本项目研究核反应堆严重事故下堆芯高温熔融物的凝固机理并开发高温熔融物的凝固模型。高温熔融物凝固过程对核反应堆事故进程及后果有极大的影响，是决定事故进程恶化的关键过程，对评估事故工况下堆芯燃料残留量以及评估事故后再临界风险尤为重要。但是目前其机理及关键因素尚不清楚，相应的模型不能准确地描述实际情况，熔融物凝固的控制途径和安全判据还未建立起来。通过本项目的研究，采用实验与理论相结合的方法，解明高温熔融物凝固机理、凝固壳的形成及形态，分析系统特征参数的定量影响，相关研究对开发相应多相热物理分析工具具有理论意义。对考虑经济性与安全性相结合的工程安全系统的设计，指导相关系统结构安全方面的改进具有实际应用价值。

Solidification mechanism of molten core under severe accidents for the nuclear power plants is studied with developing the Solidification model. Solidification process of high-temperature melt core has a great impact on the progression of nuclear reactor severe accidents and consequences, which determines the key process of deterioration of the accident process. Research on solidification is particularly important to the assessment of accident conditions, fuel residues in the core and the critical risk of the accidents. However, the mechanism and key factors are not clear and the corresponding model can not accurately describe the actual situation, the control method and Safety Criteria for solidification of the melt has not yet established. Through this project, make clear the high temperature melt solidification mechanism of the formation and morphology of the solidified shell, and analyze the quantitative impact of the system characteristic parameters with combining experimental and theoretical studies, which has theoretical significance to the development of the corresponding multi-phase thermophysical analysis tools. The research also has practical value to the Engineering Safety Features design and structure improvements for the safety consideration.