An advanced purex process based on salt-free reductants

Abstract

An advanced plutonium and uranium recovery process has been established based on two organic reductants, , -dimethylhydroxylamine (DMHAN) and methylhydrazine (MH), as U/Pu separation reagents. This Advanced Purex process based on Organic Reductants (APOR) is composed of three cycles, including U/Pu codecontamination/separation cycle, uranium purification cycle and plutonium purification cycle. Using DMHAN and MH as plutonium stripping reagents in the U/Pu codecontamination/separation cycle and plutonium purification cycle, the APOR process exhibits high performance with following highlights: 1) the process is much simpler because of the elimination of Tc scrubbing operation and the supplement extraction operation, 2) high efficiency of U/Pu separation can be achieved in the first cycle, 3) plutonium product solution of high concentration can be obtained in the Pu purification cycle with a simple extraction operation instead of circumfluent extraction or evaporation of the plutonium solution.

Theoretical Insights into the Reduction Mechanism of Np(VI) with Phenylhydrazine

“…More importantly, its isotope ( 237 Np) is the raw material for 238 Pu, which can be used to prepare nuclear power batteries . For Advanced PUREX (Plutonium Uranium Reduction EXtraction) − and SUPERPUREX, the Np separation can be achieved in the PUREX process according to the extraction difference of tributyl phosphate (TBP) for three oxidation states (Np­(VI) > Np­(IV) ≫ Np­(V)). Some highly efficient and green free-salt reductants have been studied to reduce Np­(VI) in the experiment such as aldehydes, − hydroxylamine, − oximes, , hydrazine, − and their derivatives.…”

Unveiling the Reduction Mechanism of Pu(IV) by Acetaldoxime

“…The studies on the reduction of Pu­(IV) have been explored in experiments using various reductants, including the combination of U­(IV) with hydrazine − and salt-free reductants such as formo- and acetohydroxamic acid, − tert -butyl hydroquinone, − aldehydes, , hydroxylamines, − hydroxyurea, − hydrazine, − oximes, − and their derivatives. Of these, oxime derivatives reduce Pu­(IV) to Pu­(III) in HNO 3 solution with excellent stability, fast nitrous acid scavenging, and kinetics. ,− ,− Koltunov et al first reported the reduction of Pu­(IV) by acetaldoxime in nitric acid and obtained the activation energy with the value of 87.7 ± 9.8 kJ mol –1 at 298 K .…”