Electrical conductivity, oxygen potentials and defect structures of pure UO2+x and UO2+x doped with various cations

The electrical conductivity and the oxygen potentials of pure UO2+x and UO2+x doped with various cations are reviewed. Both the electrical conductivity σ and the oxygen potentials Δanti GO2 of UO2+x doped with lower (or higher) valent cations are increased (or decreased), since lower (or higher) valent dopants can act effectively as hole (or electron) donors and can also increase (or decrease) the oxidation state of the remaining uranium ions. From the oxygen partial pressure PO2 dependences of σ and x in (U, M)O2+x (M≡metal) the defect structures are discussed, with the complex defect model consisting of oxygen vacancies and interstitial oxygen. (orig.)