Study On Corrosion Behaviors Of Three Types Of Stainless Steel In Molten LiCl-Li₂O

A lithium reduction technique has been developed as an effective method for reducingthe volume and radiation of the spent nuclear fuel, which can benefit to the disposal andmanagement of the spent nuclear fuel. In this process, structural materials used in thetechnique undertake serious corrosion in molten LiCl-Li₂O, which delayed the application ofthe new technique. To date, there have been few studies on the corrosion behavior ofmaterials in molten LiCl-Li₂O.In this paper, the temperature and Li₂O concentration inexperiment are changed to study the corrosion behaviors of three types of stainless steel,1Cr13, 1Cr17 and 1Cr18Ni9, in molten LiCl-Li₂O. Immersion experiments are used tosimulate service environment of structural material in the lithium reduction process. X-rayDiffraction (XRD) and Electron Probe Microanalysis (EPMA) are used to investigate thecorrosion behavior of these samples. It primarily discussed the corrosion mechanism andprovides useful results and testing data for selecting materials and protective coatings underthese conditions.The corrosion products of 1Cr13 stainless steel after corroded in molten LiCl and LiCl-3%Li₂O for 50h are LiCrO₂, LiFe₅O₈ and LiFeO₂. When the concentration of the Li₂Oachieved 5% and 10%, the corrosion products are LiCrO₂ and LiFeO₂. The 1Cr13 stainlesssteel suffered more severe attack in the molten LiCl-Li₂O with higher Li₂O concentration.At 650℃, the products of 1Cr13 stainless steel after corroded in molten LiCl-5%Li₂O for20h are LiCrO₂, LiFe₅O₈ and LiFeO₂. At 700℃and 750℃, the products are the same: LiFeO₂and LiCrO₂. The weight loss of the three conditions increased with increasing temperature.This can be seen that increasing temperature also speeds up the corrosion.After corrosion in LiCl-5%Li₂O at 700℃for 50h, 1Cr18Ni9 and 1Cr13 have the samecorrosion products: LiFeO₂ and LiCrO₂. 1Cr17's products also include LiFe₅O₈. The weightloss rate of 1Cr13 was significantly more than that of 1Cr18Ni9 and 1Cr17, and the weightloss rate of 1Cr17 was close to that of 1Cr18Ni9.Cr plays an important role in anti-corrosion.