First-principles molecular dynamics study of the behavior of tritium in molten LiF-BeF2 eutectic

Abstract

Molten LiF–BeF2 (FLiBe) eutectic (67 mol% LiF and 33 mol% BeF2) plays the fundamental role in the molten salt reactors (MSRs). However, the residual 6Li nuclides capture neutrons and generate the radioactive tritium nuclides, thus the tritium management is essential for the safe operation of MSRs. In this work, first-principles molecular dynamics (FPMD) simulations are applied to the investigation of the behavior of tritium in molten FLiBe. It is proved that the calculated temperature dependence of density and the coordination structure of molten FLiBe agree well with the available experimental information. Thus, it is confident that FPMD can be applied to the investigation of behavior of tritium in molten FLiBe. Finally, the coordination and electronic structures, as well as transport characteristics of various tritium moieties are studied for the understanding of the behavior of tritium in molten FLiBe.