Analysis of the mechanical effects of sudden depressurization in a nuclear reactor cooling circuit

This work studies the behavior of the internal structures of a pressurized water reactor and analyzes the three-dimensional phenomena of fluid-structure interaction during the first phase of a depressurization accident. The calculation gives the displacements and pressures at each point of the vessel, as well as the reaction forces on the core shroud. This calculation is carried out by the Plexus code, which uses the finite element method to solve a system of thermal-hydraulic equations, taking account of thermodynamic imbalance. HDR (superheated steam reactor) test results were used to validate the Plexus code. (author)