Abstract
The universal shift towards carbon neutrality has led to an increased significance in clean energy technologies. The U.S. has shown great interest in molten salt reactors (MSRs) and
concentrated solar power (CSP) plants as possible steps forward. Both of which are targeting
the use of high temperature molten chloride salts as energy generation or thermal energy
storage (TES) materials. High carbon stainless steel 316 (SS316H) is a potential low−cost
candidate structural material for energy storage and production using molten chloride salts. In
this study, the corrosion rate of SS316H in NaCl−MgCl2 salts at 700 °C was determined
through immersion testing up to 500 hours. FeCl2 was observed as the major corrosion product
while Cr and Mg accumulate on the surface of the alloy due to the formation of MgCr2O4 and
MgO. Based on the experimental results, the long−term corrosion behavior of the structural
alloy was modeled through intergranular corrosion (IGC) rates and IGC evolution (up to 500
hours) studies in COMSOL. The IGC rates reach a near steady state after 30 hours due to the
consumption of the initial moisture in the salts. However, predicting IGC rates up to a decade
reveals a negligible corrosion rate is reached once each dissolving species equilibrium potential
matches the electrode potential (Erode), which is further verified with a minor local current
density (iloc) in the channel at 10 years.