Alloy 22 disks and U-bend samples were tested in high-ionic-strength acidic and basic environments containing a variety of potentially aggressive additives, including both metal ions (e.g., lead and mercury) and anions (e.g., thiosulfate and sulfide). In acidic solutions, temperatures of 210-250°C, for test periods of 2-8 weeks, U-bend samples in the presence of Pb or Hg exhibited significant pitting and, in one case in the presence of Pb, catastrophic cracking. At temperatures around 160°C, some samples exposed to acidic media containing Pb and Hg exhibited localized corrosion. Enhanced dissolution in acidic solution was observed in the presence of thiosulfate and sulfide. Sulfur species caused noticeable oxide spalling and flaking, in addition to strongly enhanced dissolution of Alloy 22. The aggressive dopants attack or disrupt the multiple protective layers on the Alloy 22 surface.