CONDENSATION OF URANIUM HEXAFLUORIDE IN SUPERSONIC LAVAL NOZZLE-FLOW

Condensation, by homogeneous nucleation, of UF6 carried in a mixture o f argon and methane was studied experimentally in a continuously opera ting supersonic Laval nozzle. The onset of condensation was detected b y Rayleigh light scattering. Measurements of static pressure in the no zzle, together with the equations of isentropic flow, permitted the de termination of the relation between the pressure of UF6, P-k, and the temperature, T-c, at the observed onset of condensation. The experimen ts addressed conditions of condensation onset in the range 80 < T-c < 160 K and 0.1 P-k < 3.0 Torr. We found that there was no influence of the pressure of the carrier gas argon, which ranged from 3.5 to 68 Tor r at onset points, on the onset of condensation. The dependence of the supersaturation ratio on temperature at the onset could be expressed by a straight line as deduced by P.P. Wegener and B.J.C. Wu from the c lassical theory of homogeneous nucleation [Adv. Colloid Interface Sci. 7, 325 (1977)]. These results indicate that supersonic expansion in t he nozzle formed single-component droplets of UF6 in a mixture of UF6, CH4, and Ar under the experimental conditions studied herein.