MOCKA Experiments on MCCI of Metal and Oxide Melt with Siliceous Concrete

摘要

Safety assessment of nuclear power plants requires detailed understanding of the interaction of the corium with the concrete. MCCI is characterized by intense coupling of complex phenomena, such as: 1. High temperature behavior of the concrete and its decomposition; 2. Thermal hydraulics and heat transfer of the corium pool agitated by gas bubbles; 3. Physical chemistry of the multi-component melt as influenced by the changes in material composition through admixture of molten concrete and oxidation of metals; 4. Solidification processes and the behavior of interfacial crusts. Identification and quantification of these phenomena with respect to their importance for accident analysis requires a variety of integral experiments, separate effect tests and development of models and their verification. Even though extensive research has been undertaken over several years in the area of corium-concrete interaction, several subjects need further investigations. An important issue concerns the distribution of the heat flux to the concrete in the lateral and axial directions during the long-term 2-dimensional concrete erosion by a core melt. The knowledge of this partition is important in the evaluation of the consequences of a severe reactor accident.