Sorption and Precipitation of Plutonium in the Presence of Goethite at Elevated Temperatures

Technical Report · Fri Jan 28 04:00:00 EST 2011

DOI:https://doi.org/10.2172/1068294· OSTI ID:1068294

Zavarin, Mavrik ^[1]; Zhao, Pihong ^[1]; Carroll, Susan A. ^[1]; Kersting, Annie B. ^[1]

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1. Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)

We have examined the behavior of aqueous Pu(IV) and intrinsic Pu(IV) nano-colloids and interaction with goethite at 25 and 80°C and over a range of concentrations from undersaturated to oversaturated with respect to PuO₂(am, hyd). In the presence or absence of goethite, temperature does not appear to greatly affect Pu concentrations in solution. The strong affinity of aqueous Pu(IV) for the goethite surface is explained by the epitaxial growth of bcc Pu₄O₇ nano-colloids on the goethite substrate. The behavior is affected minimally by temperature. This strong affinity cannot be achieved when intrinsic Pu(IV) nano-colloids are reacted with goethite over 103 days. The results indicate that the fate of Pu is dependent on its initial form and its subsequent stability under changing geochemical conditions. Epitaxial growth of Pu₄O₇ on the goethite surface will produce a strong association between Pu and goethite, which could also lead to significant colloid-facilitated transport. Both intrinsic colloids and those sorbed to goethite have the potential to be transported with groundwater. The long-term stability and desorption characteristics of these forms of colloidal Pu will be the focus of ongoing research in FY12. A comprehensive characterization of Pu sorbed to other minerals, such as, clays is the subject of ongoing research in FY11 and FY12.

• Research Organization: Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
• Sponsoring Organization: USDOE Office of Nuclear Energy (NE), Office of Spent Fuel and Waste Disposition
• DOE Contract Number: W-7405-ENG-48; AC52-07NA27344
• OSTI ID: 1068294
• Report Number(s): LLNL--TR-468731
• Country of Publication: United States
• Language: English

Related Subjects

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY