Corrosion performance of ferrous and refractory metals in molten salts under reducing conditions

A lithium reduction technique to condition spent fuel for disposal has been developed at the Argonne National Laboratory. There is a need to ensure ad equate vessel longevity through corrosion testing and, if necessary, materi als development. Several ferrous alloys and tantalum specimens were submitt ed to a corrosion test at 725 degrees C for thirty days in an argon atmosph ere, using a lithium-chloride salt saturated with lithium metal and contain ing small amounts of lithium oxide and lithium nitride. The samples did not show dimensional or weight change, nor could corrosion attack be detected metallographically. The lithium-saturated salt system did not show any beha vior similar to that of liquid lithium corrosion. From testing in other gas compositions, it appears that the presence of oxygen in the system is nece ssary to produce severe corrosion.