The technical issue underpinning this thesis topic is the mitigation of the consequences of a loss of primary coolant accident in a pressurized water reactor with loops. It is of the utmost importance to minimize the flow of water leaving the vessel and to manage the available cold water reserves for safety injections as effectively as possible, in order to prevent or delay core flooding, overheating, and possible core degradation. To this end, the use of passive devices operating on the principle of hydraulic diodes, such as vessel flow limiters or advanced accumulators, is being considered. The subject of this thesis is the geometric optimization of this type of device, described by an immersed boundary, in order to maximize its service efficiency.
Several recent theses have shown how to introduce the Penalized Direct Forcing (PDF) immersed boundary method into the TRUST/TrioCFD software, under various spatial discretizations and for laminar and turbulent regimes. Similarly, they have ruled on the possibilities of deterministic geometric optimization in the finite-element context during simulations, based on the use of the PDF method.
After a bibliographic study of this kind of method, we will focus on the possibilities of implementation in finite volume discretization, the consideration of constraints, and the comparison to reference calculations. The latter will be carried out on academic and industrial configurations (accumulators and flow limiters).
The doctoral student will work in a R&D unit on innovative nuclear system within the IRESNE Institute (CEA Cadarache. He will develop skills in fluid mechanics and numerical methods.