Implementation of a microstructural densification model in the DIONISIO nuclear fuel simulation code

Abstract

A model to evaluate the nuclear fuel pellets densification under the combined effects of temperature and irradiation has been formerly elaborated and subjected to several separate tests which were exposed in a previous work of this team. The model considers the point defects diffusion to and from the lattice defects and the interaction between the fission fragments and the fabrication pores to give a microscopic description of the densification process. The model was recently included as a subroutine of the fuel performance code DIONISIO 3.0 and a new module, DIONISIO-FEM, was developed to simulate the sole effect of temperature during re-sintering tests. These incorporations have allowed a more detailed and precise description of the processes that take place in the fuel pellets during densification proving a very good agreement with the experimental data obtained in the open literature.