Corrosion Study of Selected Nickel-based Alloys in a High Temperature Oxidizing Molten Salt Electrolyte

摘要

Argonne National Laboratory's Chemical Engineering Division is investigating advanced structural materials for use in the electrolytic reduction step for the treatment of spent nuclear fuel. The technology includes an electrolytic reduction process that involves the liberation of oxygen in a molten lithium chloride electrolyte. This results in a chemically aggressive environment that is too corrosive for typical structural materials. A principal objective of this effort is to assess and select commercially available candidate materials for service in the electrolytic reduction process vessel. Alloys were chosen for this study based on their expected performance under the process-simulated conditions of up to 6 percent lithium oxide in lithium chloride molten salt, a temperature range of 625 deg C to 725 deg C, and up to 10 percent oxygen in an argon sparge gas. Results for selected nickel-based alloys will be discussed as well as microstructural changes associated with corrosion, possible corrosion mechanisms, and those alloying agents related to corrosion resistance.