Transpiration studies on the volatilities of PuO3(g) and PuO2(OH)2(g) from PuO2(s) in the presence of steam and oxygen and application to plutonium volatility in mixed-waste thermal oxidation processors

Abstract Transpiration experiments have been carried out to study the volatility of PuO 2 (s) in the presence of oxygen and steam. Vapor pressures have been measured for PuO 3 (g) and PuO 2 (OH) 2 (g) and thermodynamic data established for them. Thus, Δ f H 298 0 is determined to be −(562.8 ± 5.0) kJ/mol for PuO 3 (g) and −(1,018.2 ± 3.3) kJ/mol for PuO 2 (OH) 2 (g). In applying the Pu volatility data to a pilot scale mixed waste (containing both radioactive and hazardous constituents) incinerator with primary and secondary combustion chambers, it is found that Pu volatilization makes a negligible contribution to air emissions if the temperature in the secondary combustor is maintained at less than 1600 K. Chlorine- and fluorine-induced volatilities of plutonium are not considered in this analysis.