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Actinide Lanthanide Separation Process – ALSEP

Journal Article · · Industrial and Engineering Chemistry Research, 53(4):1624-1631
DOI:https://doi.org/10.1021/ie403569e· OSTI ID:1130192
Separation of the minor actinides (Am, Cm) from the lanthanides at an industrial scale remains a significant technical challenge for closing the nuclear fuel cycle. To increase the safety of used nuclear fuel (UNF) reprocessing, as well as reduce associated costs, a novel solvent extraction process has been developed. The process allows for partitioning minor actinides, lanthanides and fission products following uranium/plutonium/neptunium removal; minimizing the number of separation steps, flowsheets, chemical consumption, and waste. This new process, Actinide Lanthanide SEParation (ALSEP), uses an organic solvent consisting of a neutral diglycolamide extractant, either N,N,N',N'-tetra(2 ethylhexyl)diglycolamide (T2EHDGA) or N,N,N',N'-tetraoctyldiglycolamide (TODGA), and an acidic extractant 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (HEH[EHP]), dissolved in an aliphatic diluent (e.g. n-dodecane). The An/Ln co-extraction is conducted from moderate-to-strong nitric acid, while the selective stripping of the minor actinides from the lanthanides is carried out using a polyaminocarboxylic acid/citrate buffered solution at pH anywhere between 3 and 4.5. The extraction and separation of the actinides from the fission products is very effective in a wide range of HNO3 concentrations and the minimum separation factors for lanthanide/Am exceed 30 for Nd/Am, reaching > 60 for Eu/Am under some conditions. The experimental results presented here demonstrate the great potential for a combined system, consisting of a neutral extractant such as T2EHDGA or TODGA, and an acidic extractant such as HEH[EHP], for separating the minor actinides from the lanthanides.
Research Organization:
Pacific Northwest National Laboratory (PNNL), Richland, WA (US)
Sponsoring Organization:
USDOE
DOE Contract Number:
AC05-76RL01830
OSTI ID:
1130192
Report Number(s):
PNNL-SA-100140; AF5805010
Journal Information:
Industrial and Engineering Chemistry Research, 53(4):1624-1631, Journal Name: Industrial and Engineering Chemistry Research, 53(4):1624-1631
Country of Publication:
United States
Language:
English

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