Development of the process for the recovery and conversion of (UF6)-U-233 chemisorbed in NaF traps from the molten salt reactor remediation project

The Molten Salt Reactor Experiment (MSRE) site at Oak Ridge National Labora tory is being cleaned up and remediated. The removal of similar to 37 kg of fissile U-233 is the main activity. Of that inventory, similar to 23 kg ha s already been removed as UF6 from the piping system and chemisorbed in 25 NaF traps. This material is in temporary storage while it awaits conversion to a stable oxide. The planned recovery of similar to 11 kg of uranium fro m the fuel salt will generate another 15 to 19 NaF traps. The remaining 2 t o 3 kg of uranium are present in activated charcoal beds, which are also sc heduled to be removed from the reactor site. Since all of these materials ( NaF traps and the uranium-laden charcoal) are not suitable for longterm sto rage, they, will be converted to a uranium oxide (U3O8), which is suitable for long-term storage. The conversion of the MSRE material into an oxide presents unique problems, such as criticality, concerns, a large radiation field caused by the daugh ters of U-232 (an impurity, isotope in the U-233), and the possible spread of the high-radiation field from the release of Rn-220 gas. To overcome the se problems, a novel process was conceived and developed. This process was specially tailored for providing remote operations inside a hot cell while maintaining full containment at all times to avoid the spread of contaminat ion. This process satisfies criticality concerns, maximizes the recovery of uranium, mini. mi. zes any radiation exposure to operators, and keeps wast e disposal to a minimum.