Modeling of fragments relocation during depressurization of a nuclear fuel rod

Details

Supervisors

Legat, Vincent ; Lambrechts, Jonathan

Faculty

Ecole polytechnique de Louvain

Degree label

Master [120] : ingénieur civil mécanicien, à finalité spécialisée

Abstract

A two-dimensional numerical simulation of fuel fragment relocation during a Loss of Coolant Accident (LOCA) was conducted. The Migflow software is utilized to model the problem as a granular flow, solved using CFD-DEM, providing a more accurate representation of the interactions between the fluid and the fragments. An algorithm is presented to generate an initial configuration of particles that matches experimental results, and some examples of this algorithm are provided. A new model that includes a numerical computation of the pressure in the cladding and an estimation of the fluid's compressibility is introduced. This model is compared to more traditional models and is used to demonstrate results based on parameters such as break size and pressure gradient. These findings suggest that using an accurate model in CFD-DEM simulation enables a more precise analysis of the relocation problem and opens up possible improvements such as considering compressibility effects or using a three-dimensional representation.