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 (U0.8Pu0.2)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 (U1-xPux)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. (orig.)