Dependence of the thermal conductivity of (U, Pu) N on porosity and plutonium content

The dependence of the thermal conductivity of (U, Pu)N on porosity and plutonium content was investigated from 680 to 1600 K. The modified Maxwell-Eucken equation was applied to the experimental results for (U 0.8Pu 0.2)N pellets with 82–95% of theoretical density. The coefficients β in the equation were separately estimated for the pellets sintered at different temperatures and for those sintered with pore former particles. The plutonium content dependence was examined by use of ( U 1− x Pu x ) N pellets with x = 0, 0.2, 0.35, 0.6, 0.8 and 1.0. Prominent decrease in thermal conductivity with plutonium content was found in the UN-rich region and the temperature dependence diminished with the increase of plutonium content.