MODEL FOR THE ELECTRONIC CONTRIBUTION TO THE THERMAL AND TRANSPORT PROPERTIES OF THO2, UO2, AND PUO2 IN THE SOLID AND LIQUID-PHASES

Using existing experimental information, a unified model for the electronic density of states of ThO2, UO2, and PuO2 is formulated. Using this model we find that a unique contribution to the thermal and transport properties of solid UO2 may be attributed to the presence of quasilocalized 5f electrons lying ≈2.3 eV below the conduction band of UO2. The corresponding electron states in ThO2 and PuO2 are expected to be relatively unimportant. Estimates are made of the change in thermal conductivity as UO2 passes through its melting point. We find that at high temperatures the solid phase thermal conduction is primarily due to thermally excited electrons while in the liquid phase radiative thermal transport dominates. © 1979.