Date of download: 10/21/2017 Copyright © ASME. All rights reserved. From: The Effect of Alkali Metal and Alkaline Earth Metal Impurities on the Iodine-Induced Corrosion of CANDU Fuel Sheathing ASME J of Nuclear Rad Sci. 2017;3(4):041004-041004-11. doi:10.1115/1.4037115 Figure Legend: Photographs of slotted ring surfaces after the rings were stressed, heated, and exposed to iodine and various metal oxides. Compared with rings exposed to iodine only ((a), top), rings exposed to MgO and iodine formed a consistent rustlike layer on their surfaces ((a), bottom). (b) On the other hand, when Na2O was present, the Na2O accumulated preferentially along the inner surface of the ring, providing a potential chemical barrier. Gray or black oxide films were commonly observed on rings exposed to iodine only, as well as on rings exposed to iodine with the presence of Na2O or (c) CaO. Both the rustlike and gray/black oxide layers were readily removed upon cleaning with water and methanol.