PhD opportunities

Multi-scale modelling of the restructuring mechanisms of restructuring of UO2 fuel at high burn-up combustion rate

Thesis proposal

Area of expertiseMécanique numérique et Matériaux
Doctoral SchoolSFA - Sciences Fondamentales et Appliquées
SupervisorBERNACKI Marc
Research unitCentre de Mise en Forme des Matériaux
Keywordsphysical notions, mathematical concepts
AbstractIn nuclear fuels, when the accumulation of irradiation
of irradiation defects is accompanied by a limited possibility of
In nuclear fuels, when the accumulation of irradiation defects is accompanied by a limited possibility of restoration, a profound change can occur in the microstructure. Micrometric grains are
gradually replaced by pristine nanoscale grains
grains surrounded by micrometric pores of spherical shape.
spherical pores. This new microstructure, called High
Burnup Structure (HBS), impacts the behaviour of the
nuclear fuel under irradiation, modifying important
properties of the fuel, such as thermal conductivity and elastic properties.
The new porosity associated with HBS induces additional swelling of the fuel
of the fuel, aggravating the mechanical interaction
interaction, and can lead to the release of fission gas stored in the
The new porosity associated with HBS induces additional fuel swelling, aggravating the mechanical pellet-cladding interaction, and can lead to the release of stored fission gas in accidental transients, such as loss of coolant accidents (LOCA) or nuclear power plants.
(LOCA) or rapid reactivity insertion (RRI) accidents, which can
(RIAs), which can compromise the integrity of the rod.
This thesis work aims to identify the mechanisms behind
This thesis aims to identify the mechanisms behind the restructuring of uranium oxide fuel, using a combination of
using a combination of critical analysis of pre-existing experimental data, theoretical and numerical studies with the
and numerical studies with the aim of developing a model for
model for the formation of HBS and to include it in the
the CEA's nuclear fuel irradiation simulation platform
irradiation platform, PLEIADES.
ProfileMaster's degree in physics or materials, engineering school.
FundingFinancement d'une association ou fondation