Development of a Green Analytical Methodology for the Compositional Analysis of Actinides in Fluoride-Based Molten Salt Fuel Using X-ray Fluorescence

A Molten Salt Reactor (MSR) employs a high-temperature molten salt that serves as both a fuel carrier and a coolant, providing high efficiency, inherent safety, and low-pressure operations. The fuel employed in an MSR is typically based on fluoride salt, and precise knowledge of the fuel salt composition is crucial for safe and stable reactor performance. In this work, an X-ray Fluorescence (XRF)-based green analytical methodology has been developed for the direct analysis of actinide concentrations in fluoride-based salts. In this paper, we introduce a detailed analysis of Compton and Rayleigh scattering peaks for normalization, which is the first of its kind in these sample matrices. The present research further illustrates that, until a specific concentration level of 3 wt % of U/Th is reached, the matrix effect is absent when employing the established methodology. A comprehensive sample preparation technique was outlined, enabling the analysis of these types of fuel salt samples in their solid state without the necessity of burdensome dissolution procedures. This novel methodology was also implemented on some real fuel salt samples.