Electrical conductivity and thermoelectric power in irradiated UO2 + x

Two kinds of UO_{2 + x}, the O/U ratios of which were 2.002 and 2.004, respectively, were irradiated to a dose range between 1.14 × 10¹⁴ and 1.90 × 10¹⁸ fissions/cm³, and electrical conductivity changes were measured. A steep decrease in conductivity was observed with increasing dose up to 1 × 10¹⁵ fissions/cm³, a gradual increase followed between 1 × 10¹⁵ and 1 × 10¹⁸ fissions/cm³ and above this dose the conductivity abruptly increased. Thermoelectric power measurements were also carried out for the specimens irradiated in the dose range up to 1.90 × 10¹⁸ fissions/cm³. It might be suggested that p-type conduction contributes to the electrical conductivity in irradiated specimens up to 1.90 × 10¹⁸ fissions/cm³.