Corrosion Resistance of 316L Stainless Steel in HCL and FeCl3

Stainless steel containers made from annealed 316L are used for storing radioactive laboratory wastes including disposable gloves, polyvinylchloride (PVC) bags, and paper Kimwipes. Radiolysis of the PVC bags stored in the containers can form several by-products, including HCl acid. The question is whether the HCl acid can significantly attack the stainless steel and reduce the planned lifetime of the containers. This research is aimed at estimating the lifetime of the 316L stainless steel containers when exposed to the vapors of HCl or immersed in varying concentrations of HCl (12 M, 10 M, 1 M, 0.1 M) and 1.5 M FeCl3). The test methods included weight loss, thickness loss, potentiodynamic polarization, and electrochemical impedance spectroscopy. The preliminary test results indicate that the "uniform" corrosion occurs in concentrated HCl (12 M), but pitting occurs in FeCl3. The corrosion rate starts slowly and increases with time in HCl while the opposite happens in FeCl3.