Measurements of thermal conductivity for near stoichiometric (U0.7-zPu0.3Amz)O2 (z = 0.05, 0.10, and 0.15)

Abstract

The thermal conductivities of near stoichiometric (U0.7-zPu0.3Amz)O2 solid solutions (z = 0.05, 0.10, and 0.15) have been measured between room temperature (RT) and 1473 K under oxygen partial pressure controlled atmosphere. Thermal conductivities were obtained from the thermal diffusivity measured by the laser flash method. From the oxygen partial pressures during the thermal diffusivity measurements, the oxygen to metal ratios of the specimens were maintained between 1.999 and 2.000. The thermal conductivities decreased with increasing Am content, and could be expressed by the classical phonon transport model (λ=1/(A+BT)) up to about 1473 K. In this equation, Coefficient A values increased linearly with increasing Am content while B values were independent of Am content. The coefficients obtained from experiments could be described by the phonon scattering model theoretically, assuming cations of U4+, U5+, Pu4+, and Am3+ in the stoichiometric composition.

Keywords

• Thermal conductivity
• Nuclear fuel
• Minor actinide-bearing MOX
• Ceramics