Waste/rock interaction technology. Solubility of plutonium compounds and their behavior in soils

The solubilities of 239PuO2(c) and 239Pu(OH)4(am) under natural environmental conditions were determined. These data were then used to predict the (1) nature of the solid phases present in contaminated soils, and (2) total concentration of Pu that can be expected in soil solutions when these Pu solids are present. Based upon solubility measurements, an estimated value of the log K/sup c/ for the dissolution of 239PuO2(c) [PuO2(c) reversible PuO2 + e-] was found to be -14.8. The estimated value of the log K/sup c/ for the dissolution of 239Pu(OH)4(am) [Pu(OH)4(am) reversible PuO2 + 2 H2O + e-] was found to be -12.8. Comparison of Pu concentration in equilibrium solutions of contaminated Hanford soils with the PuO2(c) and Pu(OH)4(am) solubility lines suggested that Pu(OH)4(am) was absent from all the samples and that two of the samples contained PuO2(c). The presence of PuO2(c) was also confirmed by X-ray diffraction of Pu particles isolated from one of the samples