Effect of Fission Products on Molten Salt Corrosion for Nuclear Reactor Applications

Abstract

Molten halide salts are used in various technologically important applications like molten salt reactors and concentrated solar power. A major challenge of molten salts is their corrosivity towards structural materials. However, most of the complex interfacial phenomena related to molten salt corrosion are not well understood, primarily due to the complex impact of salt chemistry on structural material interface. Structural material corrosion is influenced by salt redox potential, fission product buildup, presence of impurities and moisture. Given the huge dependence of operations on salt chemistry, understanding the interactions between soluble fission products and structural alloys is of great importance. EuCl3 is one of the primary fission products and shown EuCl3 to cause accelerated corrosion of structural alloys in molten chloride salts. Given the more positive formal oxidation potential of Eu(III)/Eu(II) compared to nickel, iron, and chromium that are major components of the structural alloys, Eu(III) species act as a strong oxidant to cause the dissolution of these metals. This talk will highlight utilization of novel in situ optical spectroscopy technique to study time-dependent evolution of corrosion damage of metals in presence of EuCl3 as well as the EELS technique to identify changes in oxidation states of dissolved alloying elements.