Definition and characterization of refueling equilibrium for batch-operated molten salt reactors

Abstract

International audienceThis paper presents a definition of the refueling equilibrium for batch-operated molten salt reactors (MSR). Batch-operated MSR are molten salt reactors for which the refueling option considered is not continuous but batch-wise. In the present work, the molten salt reactor considered is the ARAMIS-A burner reactor, developed within the ISAC (Innovative System for Actinide Conversion) project. This project involves the main contributors of the French nuclear field: CEA, CNRS, EDF, Framatome and Orano. The study of the equilibrium cycle is relevant to evaluate a certain loading strategy for a specific reactor design, notably in terms of fuel fabrication, operating costs, fuel cycle analysis and waste management. Refueling equilibrium is reached when, for a fixed feed-salt, full end of cycle (EOC) in-salt atomic compositions do not vary one from another. In this paper, it is demonstrated that equilibrium compositions depend only on feed-salt properties and a direct method for equilibrium computation is studied. Last, data-sets of equilibrium composition are generated and deep learning models (multilayer perceptrons, a.k.a MLP) are trained so as to provide satisfactory estimation of the equilibrium associated to the fuel composition in the feed-salt. Such MLP models provide precise estimations for dynamic fuel cycle simulation analysis