Conversion of uranium dioxide and real spent nuclear fuel into nitrates

Gas-Phase Conversion of the U(VI), Sr, Mo, and Zr Oxides in Nitrating Atmosphere

“…It is stated in [9] that U and Pu in the course of the gasphase conversion will transform into water-soluble compounds, whereas the fission products, in particular, Tc, will remain in the oxide form. Bondin et al [10] studied the conversion of the real irradiated fuel from a WWER-1000 reactor and of its simulants in the N 2 O 4 -H 2 O system. The possibility of the conversion of real SNF to obtain nitric acid solutions with high uranium concentration was demonstrated.…”

Uranium extraction from TRISO-coated fuel particles using supercritical CO2 containing tri-n-butyl phosphate

“…To further reduce the waste, a new method that converts uranium oxides into solid nitrate using liquid N 2 O 4 followed by the extraction of the converted nitrate with supercritical CO 2 containing TBP was recently developed [23][24][25]. After the conversion reaction, the remaining N 2 O 4 (b.p.…”

Conversion of Ceramic UO2Pellets for HTR-10 Fuel Elements into Nitrate with N2O4

“…Recently, liquid N 2 O 4 was used to convert actinide and lanthanide oxides into their nitrates in solid form, and then the nitrates were extracted with TBP in supercritical CO 2 . , This novel method provides a potential prospect for reprocessing of SNF from HTGR to reduce generation of secondary liquid waste. Especially, the conversion process with N 2 O 4 is attractive because once SNF are converted into solid nitrates there are other low-water technologies to recover uranium and plutonium from solid nitrates, such as ionic liquid extraction, electrodeposition, and so forth, besides supercritical fluid extraction. − Although there are several researches about conversion of actinide and lanthanide oxides with N 2 O 4 into their nitrates, but the ceramic UO 2 pellet is ceramic material with large particle size and low chemical activity, its reaction behavior with N 2 O 4 is unknown.…”