Exploring the Complex Chemistry of Uranium within Molten Chloride Salts

Abstract

Harsh environments represent a unique opportunity to explore new frontiers in chemistry while developing novel tools to meet global needs. Exploring the chemistry of uranium within molten salts is a key example. Actinide chemistry within the highly ionic environment of a molten salt is poorly understood, particularly in the presence of common salt impurities or without active oxidation state control. Delving into this chemistry can provide new insight into actinide and f-electron interactions. Furthermore, expanding our chemical knowledge can also enable advances in the deployment of molten salt reactors or molten salt recycle schemes. Both molten salt applications aim toward providing green and reliable energy as well as critical materials for the world. Here, the utilization of visible absorbance and Raman spectroscopies to understand and quantify U within chloride-based salt eutectics is discussed. Furthermore, machine learning techniques in the form of chemometric modeling are developed and described, providing advanced analytical tools to quantify and characterize the U present. These tools are then leveraged to monitor and explore the dynamic fundamental chemistry of U within chloride-based salt melts without active oxidation state control.