The Laboratory for the Analysis of Radioelement Migration (LAMIR) at the Institute for Research on Nuclear Systems (IRESNE) of the CEA Cadarache has developed a set of measurement methods to characterize the release of fission products from nuclear fuel during transient thermal transients. For these transients, it is important to simulate the mechanical stresses associated with temperature changes that could lead to fracturing of the tested fuel samples . This thesis focuses on modeling hypothetical and very rapid accidental power transients. Its objective is to implement a new model based on the thermodynamics of irreversible processes (TIP).

The first part of this thesis will aim to validate the thermomechanical coupling model in TIP, which was proposed in our laboratory (https://www.mdpi.com/2813-4648/3/4/33). This will be an essentially analytical approach to establish the orders of magnitude of the various mechanisms involved. The second part will apply this formalism to experimental results obtained during rapid heating experiments using laser beams.

One of the main challenges of numerical simulation with TIP is calculating the temperature and stress fields simultaneously, rather than sequentially as in current models. We will start with a 1D program (in Python or another language) that will be progressively refined. Comparing the results obtained with TIP and with current models will help us identify situations in which TIP-specific couplings must be taken into account to achieve accurate predictions.

The PhD candidate will benefit from the support of experts in thermodynamics, mechanics, and programming. The research will lead to scientific publications and conference presentations. Owing to the diversity of the fields involved, this thesis topic offers excellent career prospects in both industry and academic research.