The Calculation of the Kinetic Rate Constants for LiF and BeF2

Abstract

In the HYLIFE inertial confinement fusion reactor occurs in pulses several times every second. X-rays ablate material from the molten LiF-BeF[sub 2] salt (Flibe) jets used to protect the reactor vessel, generating a hot dissociated partially ionized vapor. Further evaporation occurs as the vapor radiates to the jets. Eventually the vapor must be condensed to restore sufficient vacuum for the next shot. Rate of condensation determines the permissible fusion repetition rate. Analysis here shows that recombination will be fast making it possible to assume quasi-equilibrium in vapor phase. Scaling shows that convective transport in the reactor dominates over diffusive transport over length scales the order of salt droplet diameters, and thus no significant separation or concentration of species will occur, except in very thin (micron scale) layers next to condensing surfaces. Without diffusion, the local stoichiometry of the mixture will remain fixed at the initial composition of 33%BeF[sub 2] and 67%LiF, with traces of tritium, helium, and other species. The gas dynamics in the reactor cavity depend upon the equation of state of gaseous Flibe. Because the chemical kinetics are fast, and the stoichiometry is fixed, a single relationship between pressure, temperature, and specific volume can be used to describemore » the state of the vapor phase, even at high temperatures where dissociation and ionization occur.« less