A Review of Electrochemical and Non-Electrochemical Approaches to Determining Oxide Concentration in Molten Fluoride Salts

Abstract

The design of reactor core and heat transfer systems for molten salt reactors (MSRs) and fluoride-salt cooled high temperatures reactors (FHR) necessitates a precise understanding of oxide contribution to thermophysical and chemical properties of the molten salt medium [1]. The dissolved oxide content in the melt can vary during reactor operation due to transmutation or migration to/from outside the core. Therefore, it is important to develop capabilities to quantify the oxide concentration at reactor conditions such as temperatures exceeding 500 oC. As part of the oxide sensor design process, a literature review of electrochemical and non-electrochemical approaches to determining oxide concentration in molten fluoride salts was conducted and an evaluation of various methodologies is presented here. This evaluation was the basis for selecting electrochemistry as the most promising technique with which to develop an oxide sensor.