Laboratory tests were conducted on iron, nickel, titanium, and cobalt base alloys and zirconium 702, primarily at temperatures of 95 deg to 400 deg C for exposure periods of 15 days in a 60 vol % H2O, 40 vol % HCl gaseous mixture. The alloys were also exposed for a period of 66 days. Field tests were conducted in a rotary calciner and a fluidized bed decomposer using the more corrosion-resistant alloys from the laboratory tests. For the laboratory tests, titanium and cobalt base alloys showed the lowest corrosion rates at 140 deg to 380 deg C, and the Ti-O2 Pd alloy exhibited the lowest corrosion rates at 95 deg to 140 deg C. The conditions for field tests were found to be less severe than for the laboratory tests, resulting in lower corrosion rates. Element profiles obtained with auger electron spectroscopy indicated that the most prevalent corrosion-resistance process for most nickel base alloys was gaseous oxidation involving O2. The major process opposing this was HCl attack, which resulted in thinning of the oxide portion of the film and the formation of nickel chloride. Titanium buildup at the film-metal interface of rene 41 samples helped give rene 41 an extremely low rate of corrosion.