NUMERICAL AND EXPERIMENTAL INVESTIGATION OF NUCLEAR REACTOR CORE MODELED BY A POROUS MEDIA

摘要

This study is about the safety of nuclear reactor core when it is subjected to seismic loading. In order to reduce the uncertainty margin of present day codes, we propose to develop a numerical code including the nonlinear behavior of the structure and the coupling with fluid flow. The challenge of this work is to find out a tractable model taking the structure complexity into account. In this paper we model the nuclear reactor core mechanical behavior including the dynamics of both fuel assemblies and fluid. Each rod bundle is considered as a deformable porous media, so the velocity field of the fluid and the displacement field of the structure are defined in the whole domain space. Fluid part and structure part are first of all considered separately, and secondly, the two parts are coupled. The motion equations of the structure are obtained by a Lagrangian formulation, and to allow fluid structure coupling, the motion equations of the fluid are obtained by an Arbitrary Lagragian Eulerian formulation. The finite elements method is applied to spatially discretize the equations. 2D numerical simulations are compared with experimental data.