Direct Extraction of Uranium-Lanthanide Oxides in Tributyl Phosphate
- Savannah River National Laboratory (SRNL), Aiken, SC (United States)
Abstract Direct extraction of used nuclear fuel (UNF) in an organic solution could be more efficient than the previous practice with aqueous solutions. However, the UNF would need to be treated via voloxidiation before being processed using solvent extraction. The voloxidation process can form oxide and/or nitrate compounds. This work investigated the dissolution of uranium/lanthanide oxides in 30 vol % TBP diluted in dodecane (pre-equilibrated with 4 M nitric acid) in a glass reactor with air sparging to ascertain the uranium/lanthanide oxide dissolution behavior prior to scaling the process. The uranium/lanthanide oxides were prepared by co-precipitating uranium/lanthanide nitrates with hydroxide and then calcined to form a mixed oxide. While the relative concentrations of the lanthanides are not representative of used nuclear fuel, the neodymium and erbium allowed ease of tracking dissolution with visible spectroscopy. Cerium was used as a surrogate for plutonium. The dissolution rate of the oxides was similar but incomplete. A miniscule amount of cerium, as cerium oxide, took several months to slowly dissolve; however, when co-precipitated with uranium and other lanthanides, a significant amount of cerium dissolved readily.
- Research Organization:
- Savannah River National Laboratory (SRNL), Aiken, SC (United States)
- Sponsoring Organization:
- USDOE Office of Environmental Management (EM); USDOE Office of Nuclear Energy (NE). Material Recovery and Waste Form Development (MRWFD) program
- Grant/Contract Number:
- 89303321CEM000080
- OSTI ID:
- 2557435
- Report Number(s):
- SRNL-STI--2024-00074
- Journal Information:
- Separation Science and Technology, Journal Name: Separation Science and Technology
- Country of Publication:
- United States
- Language:
- English
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