High-temperature oxidation and corrosion of structural materials in moltenchlorides

A molten salt-based process for treatment of spent oxide fuels is under dev elopment at the Argonne National Laboratory. A major part of the developmen t effort involves identification of corrosion-resistant structural material s for the process vessels. Coupons of two stainless steels, tantalum, and t wo Inconel alloys were submitted to a corrosion test in an argon atmosphere with 10% oxygen. The coupons were partially immersed in molten lithium chl oride salt containing small amounts of lithium metal, lithium oxide, and li thium nitride. Two sets of coupons were tested, the first at 750 degreesC f or 30 days and the second at 650 degreesC for 6 days. Coupons of the first set corroded completely. In the second set of coupons, all corroded to some extend, but Inconel 600 showed the best performance overall. The salt-expo sed region generally showed the greatest corrosion in the other coupons. On e of the 316L SS coupons was welded and the weld area was severely attacked .