Solubility Of Uranium And Plutonium In Alkaline Savannah River Site High Level Waste Solutions

Five actual Savannah River Site tank waste samples and three chemically-modified samples were tested to determine solubility limits for uranium and plutonium over a one year time period. Observed final uranium concentrations ranged from 7 mg U/L to 4.5 g U/L. Final plutonium concentrations ranged from 4 (micro)g Pu/L to 12 mg Pu/L. Actinide carbonate complexation is believed to result in the dramatic solubility increases observed for one sample over long time periods. Clarkeite, NaUO2(O)OH · H2O, was found to be the dominant uranium solid phase in equilibrium with the waste supernate in most cases.