From melt jet break-up to debris bed formation: A review of melt evolution model during fuel-coolant interaction.

• The models of the melt evolution and the main factors affecting the jet-breakup length were introduced. • The experimental and simulation research on the morphology of debris bed were extensively summarized. • The models that can be applied to the code and the future development direction were prospected. When a severe accident occurs in a nuclear reactor, fuel–coolant interaction (FCI) may occur and cause steam explosion. Energetic FCI or steam explosion will threaten the integrity of the containment and even cause radioactive leakage. Therefore, the research and evaluation of the morphology and development of the melt in the FCI process is very important. In recent decades, many scholars have conducted theoretical and experimental research on this phenomenon, and formed a large number of mathematical and physical models for the degradation, evolution and relocation of the melt. This study retrospects and summarizes the experimental and theoretical research on the FCI phenomenon, and describes the behavior of the melt in the entire evolution process from the melt jet to debris bed. In addition, on the basis of literature review, the models of each stage are classified according to the formation mechanisms and applicable conditions. Finally, in the present study, the future development direction is prospected on the ground of the previous research results. [ABSTRACT FROM AUTHOR]