Effect of the fluid structure interaction on the dynamic response of a PWR reactor core

The criterion retained for the design of the fuel assembly mixing grids under accidental dynamic loads (earthquake and LOCA) consists of checking that the maximum impact force on the grids does not exceed their resistance to dynamic buckling. The first stage in design is therefore the calculation of the reaction of the core to these accidental stresses. This article describes the approach which determines lateral loading on the fuel assembly mixing grids during earthquake. In this formulation, forces induced by the fluid structure interaction are taking into account. And a comparison between the dynamic response of the core with or without taking into account the fluid structure interaction is presented