Thermophysical Properties of Materials
The thermophysical properties of uranium hexafluoride: Properties in the region of dense gas and liquid
V. V. Malyshev I. V. Kurchatov Institute of Atomic Energy
Abstract:
Updated results of experimental studies of the thermophysical properties of uranium hexafluoride
$(\rm UF_6)$ were obtained by processing the author's data using the Origin-
$8$ program. Updated
$\rm UF_6$ state parameter values in the area of vapor–liquid equilibrium and updated data for the heat of vaporization were obtained. A physical and mathematical method for determining the critical temperature from experimental data on the boundary curve (binodal) has been developed, which made it possible to refine the critical parameters of
$\rm UF_6: T_c = 504.6 \pm 0.5$ K,
$\rho_c = 1.385 \pm 0.0015$ g/cm
$^3{,}~P_c = 45.5 \pm 0.3$ bar. Using
$P$–
$V$–
$T$ data two virial equations of state for a dense and highly compressed
$\rm UF_6$ gas were constructed. One of them describes the experimental data for a dense gas in the entire studied range of state parameters with a standard deviation
$MSD$ of
$0.47$ bar and
$0.56\%$. The second equation provides the definition of pressure for
$\rm UF_6$ with
$MSD = 0.16$ bar and
$0.36\%$ in the entire subcritical region. The data for the second virial coefficient for
$\rm UF_6$ in the temperature range
$310$–
$592$ K were updated. The equation of state for liquid
$\rm UF_6$ is presented for the first time, which describes the experimental data with
$MSD$ less than
$7$ bar and
$6\%$ in the temperature range
$453$–
$493$ K, density from
$\rho_l$ at the phase boundary up to
$2.9$–
$3.1$ g/cm
$^3$ and pressures up to
$200$–
$240$ bar. The description of the experimental high-pressure equipment and the methodology for conducting research and determining the parameters of the state of
$\rm UF_6$ is given.
UDC:
536.71
Received: 30.03.2021
Revised: 07.09.2021
Accepted: 28.09.2021
DOI:
10.31857/S0040364422030139
Fulltext:
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