Volatile molecule PuO3 observed from subliming plutonium dioxide

Mass spectrometric measurements of effusing vapours over PuO2 and (U, Pu)O- 2 indicate the presence of volatile PuO3 (g) molecules. The formation of pl utonium trioxide vapour is due to a chemical process involving oxygen adsor bed during oxidation of the sample. Although in the examined samples, the f raction of trioxide effusing in vacuo was of the order of 0.02 ppm of the p lutonium content, under steady-state oxidation conditions it has been shown that the process can have a relevant effect on the sublimation rate of the dioxide. (C) 2000 Elsevier Science B.V. All rights reserved.