Thermophysical properties of uranium hexafluoride. Properties in the rarefied-gas region

Updated results of experimental studies of the thermophysical properties of uranium hexafluoride $(\rm UF_6)$ in the rarefied-gas region in the temperature range from $287$ to $368$ K, the range of pressures from $53$ to $750$ Torr, and the range of gas densities from $0.00188$ to $0.0118$ g/cm$^3$ were obtained by processing the author’s previous data using the Origin-$8$ graphic-mathematical program. Updated $\rm UF_6$ state parameter values in the region of vapor-solid equilibrium and updated data for the heat of sublimation were obtained. On the basis of $P$–$V$–$T$ data, an equation of state for $\rm UF_6$ was constructed that provides twice the approximation to the experimental pressure data with a standard deviation of $0.53$ Torr as compared to the previous equation and $0.12\%$ over the entire range of state parameters studied. Data were updated for the second virial coefficient. We used uranium hexafluoride with a natural content of uranium isotopes and a purity of $99.98$ vol $\%$. A description of the experimental equipment and methods of research and processing of experimental data are given.