Fluidized-Bed Fluoride Volatility Processing of Irradiated UO₂Fuels

Nitrogen Trifluoride-Based Fluoride- Volatility Separations Process: Initial Studies

“…Isothermal testing to provide a more precise thermal reaction profile and to develop kinetic models are needed. Chilenskas (1968) found that 44 to 71 percent of the ruthenium was volatilized when they treated irradiated UO 2 with BrF 5 and that fluorine treatment released 3.2 to 14 percent of the total ruthenium. The complexity of the ruthenium fluorination reaction with fluorine was highlighted by investigations of Corbin et al (1980) Our initial studies indicate that NF 3 will fluorinate and oxidize RuO 2 to a volatile fluoride.…”

“…Similar behavior can be expected for technetium compounds. Chilenskas (1968) found in several experiments that < 51 to 76 percent of the molybdenum was released during fluidized-bed treatment with BrF 5 of irradiated UO 2 . In contrast, Table 5-1 shows that molybdenum is not volatilized by voloxidation even at 1500ºC.…”

“…Without the 550°C isotherm, the niobium volatilization would not have been obvious. Chilenskas (1968) reports that using bromine pentafluoride (BrF 5 ) removed 0 to 1.9% of the niobium in irradiated UO 2 in five fluidized bed experiments and molecular fluorine removed 0 to 5.8% of the niobium from the heel remaining after BrF 5 treatment to remove the uranium.…”

“…Fluorination technologies have been used historically to convert various uranium feedstocks to uranium hexafluoride (UF 6 ) for 235 U isotope enrichment (Schmets 1970;Shatalov et al 2001;Kamoshida et al 2000) and have been discussed for nuclear-fuel recycling (Chilenskas 1968;Jonke 1965;Levitz et al 1969), nuclear materials separations (Galkin et al 1990), purification (Schmets 1970;Stephenson et al 1967), and U.S. Department of Energy (DOE) site decontamination (Scheele et al 2006;Del Cul et al 2002). The separations processes rely on the ability of some actinides and fission products to form volatile or semi-volatile fluorides to effect separations from other nuclear fuel constituents that do not form volatile fluorides or oxyfluorides.…”

A Conceptual Design Study of a Fluoride-Volatility Plant for Reprocessing LMFBR Fuels.

“…Data (for example, Ref. 70) indicate that complete removal of a fission product by volatilization from the bed of fluorinator A is unlikely. CBeta plus gamma energy, assumed to be completely converted to heat.…”