активна зона, важка аварія, відмова корпусу, моделювання, розплав, феноменологія, CFD, CFX, RELAP5.


The process of a severe accident at a nuclear power plant is characterized by its complexity, versatility and wide relationships. When modeling the in-vessel phase of a severe accident, there are significant uncertainties, primarily related to the movement of materials of the destroyed core to the lower part of the reactor vessel, as well as its subsequent heating and accompanying high-temperature physical processes. A detailed comprehensive study of these processes will allow us to reliably predict the dynamics of a severe accident and correctly determine the time of failure of the reactor vessel and justify more effective actions of personnel in managing severe accidents and emergency response.

The article presents an analysis of the course of a severe accident, identifies and analyzes the main phases of the in-vessel phase of a severe accident. The analysis of processes and phenomena characteristic of these phases is carried out. The main uncertainties that arise when modeling the processes of a severe accident within the reactor vessel are considered. To eliminate/reduce uncertainty, an approach to conjugate severe accident modeling using the ANSYS CFX CFD code and the RELAP5/Mod 3.2 system thermohydraulic code is proposed.


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