Steam generators are essential components of nuclear reactors whose main function is heat exchange. The chemical species present in steam generators are the cause of many parasitic phenomena (clogging, fouling, sludge deposition, etc.). Numerical simulation of species transport, taking into account the migration of chemical species and exchanges between species, both intra- and inter-phase, will allow a better understanding and better management of these problems. Numerical resolution of species transport systems presents real difficulties, in particular the management of the appearance and total disappearance of certain species, high void rates, as well as rapidly excessive calculation times.

While relying on the new code for nuclear components developed at STMF, the thesis will address the following three main scientific issues:
• Upstream, the analysis of numerical methods allowing in particular the management of evanescence, as mentioned above, and thermo-hydraulic modeling at high void rates. For this, we will rely on the PolyMAC and PolyVEF numerical schemes, already implemented in the component code.
• The physical modeling of a steam generator in the new component code, via the addition (in C++) of correlations specific to steam generators, the completion of the state laws already available, etc..
• The determination of the major chemical species to be transported, in order to be able to take into account both thermo-hydraulics and chemistry. The algorithmic coupling between thermo-hydraulics and chemistry, taking into account feedback, being the long-term objective.

While benefiting from the existing parallelization of the component code, the thermo-hydraulic and chemical modeling will be done taking into account the constraints on computation times.