Countercurrent Actinide Lanthanide Separation Process (ALSEP) Demonstration Test with a Simulated PUREX Raffinate in Centrifugal Contactors on the Laboratory Scale

Abstract

An Actinide Lanthanide Separation Process (ALSEP) for the separation of trivalent actinides (An(III)) from simulated raffinate solution was successfully demonstrated using a 32-stage 1 cm annular centrifugal contactor setup. The ALSEP solvent was composed of a mixture of 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (HEH[EHP]) and N,N,N′,N′-tetra-(2-ethylhexyl)-diglycolamide (T2EHDGA) in n-dodecane. Flowsheet calculations and evaluation of the results were done using the Argonne’s Model for Universal Solvent Extraction (AMUSE) code using single-stage distribution data. The co-extraction of Zr(IV) and Pd(II) was prevented using CDTA (trans-1,2-diaminocyclohexane-N,N,N′,N′-tetraacetic acid) as a masking agent in the feed. For the scrubbing of co-extracted Mo; citrate-buffered acetohydroxamic acid was used. The separation of An(III) from the trivalent lanthanides (Ln(III)) was achieved using citrate-buffered diethylene-triamine-N,N,N′,N″,N″-pentaacetic acid (DTPA), and Ln(III) were efficiently back extracted using N,N,N′,N′-tetraethyl-diglycolamide (TEDGA). A clean An(III) product was obtained with a recovery of 95% americium and curium. The Ln(III) were efficiently stripped; but the Ln(III) product contained 5% of the co-stripped An(III). The carryover of Am and Cm into the Ln(III) product is attributed to too few actinide stripping stages, which was constrained by the number of centrifugal contactors available. Improved separation would be achieved by increasing the number of An strip stages. The heavier lanthanides (Pr, Nd, Sm, Eu, and Gd) and yttrium were mainly routed to the Ln product, whereas the lighter lanthanides (La and Ce) were mostly routed to the raffinate.

Effect of metal complexation on diglycolamide radiolysis: a comparison between ex situ gamma and in situ alpha irradiation

“…The ethyl hexyl derivative, T2EHDGA (tetra 2-ethyl hexyl diglycolamide), and methylated derivatives of TODGA have also been under investigation for nuclear fuel reprocessing. [22][23][24][25][26][27][28][29][30][31][32] Radiolytic and hydrolytic degradation of DGA has been under recent investigation. Many studies have utilized external gamma irradiation sources to irradiate TODGA under different solvent conditions to induce degradation.…”

“…The ethyl hexyl derivative, T2EHDGA (tetra 2-ethyl hexyl diglycolamide), and methylated derivatives of TODGA have also been under investigation for nuclear fuel reprocessing. 22–32…”

Lanthanide‐Based Complexes Containing a Chiral trans‐1,2‐Diaminocyclohexane (DACH) Backbone: Spectroscopic Properties and Potential Applications

“…In the field of lanthanide and actinides ion extraction, the well‐known hydrophilic complexing agent CDTA (trans‐1,2‐DACH‐N,N,N’,N’‐tetraacetic acid), used as a “masking agent”, is able to suppress the interference caused by the co‐extraction of Zr(IV) and Pd(II), even in highly acidic conditions, when extracting lanthanides (Ln(III)) and minor actinides (An(III)), such as americium and curium [19,20] …”

Synthese und Charakterisierung von sp2-, sp3- und Pyrocarbonaten

“…Furthermore, this phase may be suitable for the solidification of actinide and lanthanide rich aqueous nitrate solution received from Actinide Lanthanide Separation (ALSEP) like processes, employed in the recycling procedures of spent nuclear fuel. [105,106] C arbonates play a fundamental role in the global carbon cycle and have therefore been extensively studied. 1,2 In nature, trigonal calcite (CaCO 3 ), one of its high-pressure polymorphs, orthorhombic aragonite, and the "double carbonate" dolomite [CaMg(CO 3 ) 2 ], dominate.…”

“…Actinoid-haltige Nitratlösungen, welche einer Ausfällung bedürfen. [105,106] Diese könnten dann über die Synthese von Ba 0.9 Ca 1.1 [CO 3 ] 2 kristallisiert werden.…”