MEASURED EFFECTIVE THERMAL CONDUCTIVITY OF URANIUM OXIDE POWDER IN VARIOUS GASES AND GAS MIXTURES

摘要

As a part of an investigation of the effective thermal conductivities of powders, this study was undertaken to determine the effective conduc¬tivity of uranium oxide UO2 powder with a density of 59.5 percent of the density of the solid uranium oxide at temperatures between 200° and 1500° F. Helium, argon, and nitrogen gases and mixtures of helium-argon and xenon-krypton gases were introduced into the powder void, and the experimental effective thermal conductivities of the gas-powder mixtures were determined. All tests were performed at a gas pressure above the breakaway pressure, where the thermal conductivity is independent of pressure.nA method for determination of the relative thermal conductivity of the solid was devised from knowledge of the effective conductivity of the powder and the conductivity of the gases used in the two-phase sys¬tem. This method was applied to the uranium oxide used in this investi¬gation to determine its relative thermal conductivity through the 200 to 1500° F temperature range.