New simulation controls for the molten salt reactors related neutronic evolution code REM

The in-house precision-driven material evolution code REM has been developed since the early 2000s at CNRS/LPSC Grenoble for the study and optimisation of molten salt reactors (MSR). In recent years, a particular family of these reactors has been of great interest to many players in the industry, such as the Orano group: MSRs operated as plutonium and minor actinide converters. Depletion simulation purposes has led to the development of new methods for managing supplies and the addition of new constraint parameters to the REM code. These new developments have made it possible to add new physico-chemical constraints of interest in the study of burner MSRs, such as control of the alkali or alkaline-earth fraction, or control of the volume by constraining the supply or by adding a dynamic expansion tank. These new perspectives have led to work on the numerical stabilisation of the system and the especially supplies, which has smoothed out some reactor characteristics and opened the way to interesting new research possibilities. Finally, chemical considerations on the valency of the elements and the electroneutrality of the salt raise questions about the different feeding strategies to be studied and could lead to the development of a new model for extracting materials.