Technical Challenges in the Implementation of Particle Image Velocimetry Measurements for Molten Chloride Salts

Abstract

Molten salts have garnered interest as heat transfer fluids in Gen IV nuclear reactor designs, concentrated solar power, and thermal energy storage due to their high operating temperatures and low cost. However, there is a lack of experimental data for radiation-induced convection mechanisms in these fluids, introducing a significant source of uncertainty into designs. Particle image velocimetry (PIV) has recently been implemented for flow visualization in nitrates, which are of interest in intermediate heat transport systems and thermal energy storage. Several challenges still need to be addressed in order to extend this technique to molten chlorides, which are more chemically aggressive but are of greater interest as fuel carrier and coolant salts. Chlorides are optically semi-transparent, resulting in a strong coupling of radiation and convection at high temperature. This paper outlines ongoing work in the implementation of this technique, including optical window material compatibility and salt selection.