Dynamics of a Nuclear-Reactor Shell Structure in an Incompressible Fluid

Abstract

In this paper, a numerical model of dynamical interactions of structures with fluids in a pressurized water reactor (PWR) vessel is described. The present investigation forms part of a more extended experimental and theoretical program in which the former HDR-reactor is used as a test facility [1, 2]. Similar fluid-solid interaction simulations are described in [3, 4]. The goal of the computation is to determine the stresses which are induced in the core barrel during a blowdown accident which is assumed to be initiated by break of one of the cold legs of the primary coolant circuits, see Fig. 1. It has been argued [1, 2] that the computed stresses are significantly reduced if the elasticity of the (rather thin) core barrel is taken into account (the vessel itself is assumed to be rigid). The calculation of the fluid motion during a blow-down is a hard problem on its own because of the complicated three-dimensional (3D) geometry and diversity of physical effects involved (inertia, friction, evaporation, compressibility etc.).