The effect of long-term corrosion on a molten salt pump

Abstract

Solar thermal plants commonly plan their operation for a 25 years period, therefore, it is important to accurately predict and evaluate the damage and faults occuring for that long period. Among all components, we find that choosing the heat storage medium (molten salt) and the material (steel) used in the equipment and pipping plays a crucial role in the plant’s design. We tested the long-term corrosion effect of the stainless steel used in the molten salt pump (AISI 316L) having a low melting point ternary mixture composed of 30wt.%LiNO3 + 57wt.%KNO3 +13 wt.%NaNO3 tested over a period of more than 6 years, corresponding to 30,000 hours of operation in a pilot experimental facility at the University of Antofagasta (Chile).