Predictive calculations of volatilities of metals and oxides in steam-containing environments

Predictive methods are developed for estimating the bond energies and free energy functions of volatile species having the general formula MO/sub x/ (OH)/sub y/, in order to shed some light on the mechanisms and extent of steam accelerated volatilization processes. A specific example of applying the data is illustrated for the case of a proposed underground radioactive waste disposal process, where oxides of radionuclides are allowed to equilibrate with 100 atm steam and 10-2 atm oxygen at 1000 to 2000K. Vapor species found to have high volatilities include Cs2(OH)2, CsOH, AmO2(OH)2, AmO(OH)3, UO2(OH)2, NbO(OH)3, PuO2(OH)2, CeO(OH)2, Ba(OH)2, and Eu(OH)3. Thermodynamic data are tabulated for all possible monomeric species for this specific example