William H. Howland¹, Richard W. Smith¹, Bruce F Kammenzind¹, Mikael Christensen², Volker Eyert², Erich Wimmer²; ¹Naval Nuclear Laboratory, ²Materials Design, Inc.

A typical composition of nuclear-grade zirconium alloys is more than 98 percent zirconium and less than 2 weight percent of tin, niobium, iron, chromium, nickel and other metals. A percentage of these impurities go into solution in the corrosion based zirconium oxide film. The alloying elements in zirconia solution will demand a response from intrinsic point defects such as oxygen anion vacancies and conduction band electrons. Additionally, contaminants such as Nitrogen can greatly enhance corrosion rates as point defects in zirconia by both influencing transport of corrosion species through the protective oxide barrier layer, by influencing corrosion transition, or both. To this end, this work determines the influence of Nitrogen on the transport properties of oxygen anion vacancies and conduction band electrons and the mitigating effects of common alloying elements such as Sn and Nb. The evolution of these point defects under irradiation is discussed.