A Study on the Corrosion Behavior of Stainless Steel and Heat-Resistant Alloy in Molten Salts of LiCl and LiCl-Li_2O

摘要

In the development of the advanced spent fuel management process based on the molten salt technology, it is essential to choose the optimum material for the process equipment handling molten salt. The corrosion behavior of SUS 304L, SUS 316L, More 1 and Super 22H in molten salts was investigated in the temperature range of 650-850 deg C. In a molten salt of LiCl, a dense protective oxide scale of LiCrO_2 was formed, following growth of oxide scale with parabolic kinetics. But in a mixed molten salt of LiCl-Li_2O, a porous non-protective scale of Li_x(Cr, Ni, Fe)_(2-X)O-2 was formed, following growth of oxide scale with linear kinetics. As the increase of the temperature up to 850 deg C, the corrosion rate increased slightly in molten salt of LiCl. But in a mixed molten salt of LiCl-Li_2O, the corrosion rate increased rapidly above 750 deg C. The corrosion behaviors of SUS 304L and SUS 316L was similar to those of More 1 and Super 22H. But SUS 304L and SUS 316L showed higher corrosion resistance than More 1 and Super 22H.