Prediction of the critical constants and the saturation vapor pressure of tritium oxide

By means of a modified corresponding states principle developed by the present authors for the vapor pressures of H/sub 2/O isotopes, a few experimental data for the vapor pressure of tritium oxide (T/sub 2/O), available at lower temperatures, have been extrapolated to the critical temperature. By the use of the extrapolated saturation curve and an empirical relationship between the critical pressure P /sub C/ and the critical temperature T /sub C/, the location of the critical point of T/sub 2/O on the P-T plane has been estimated. The critical density p/sub C/ has also been estimated on the assumption that the critical molar densities are identical among the H/sub 2/O isotopes. The critical constants thus obtained are T/sub C/ = 641.7 K, P/sub C/ = 21.41 MPa, and p/sub C/ = 393 kg/m/sup 3/. An equation for the saturation vapor pressure of T/sub 2/O has been developed. The uncertainty of this equation has been developed. The uncertainty of this equation has been estimated at +-0.4% in the entire temperature range.