Mechanical interaction of bowed hexagonal fuel assemblies in PWR core

Abstract

Due to the lateral and axial forces or irradiation growth, nuclear fuel assemblies (FAs) are prone to bowing during reactor operation. In some cases, FAs can even mutually contact. The paper focuses on the modelling of the bowed hexagonal FAs in mutual interaction considering complex operation conditions given by coolant pressure pulsations. The multi-stage modelling is used to describe the behaviour of the chosen FA in the reactor core. A possible contact between FA and reactor core–shell is also taken into account. All the analyses are performed with respect to the fuel burn-up that significantly influences FAs dynamic behaviour.