Abstract
Organic solutions comprising the Actinide Lanthanide Separation Process (ALSEP) solvent consisting of 0.5 M 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester (HEH[EHP]) and 0.05 M N,N,N’,N’-tetra(2-ethylhexyl)diglycolamide (T2EHDGA) in n-dodecane were subjected to low LET and high LET irradiation before and after equilibration with an aqueous phase of 3 M HNO3. Degradation dose constants revealed greater ligand degradation due to gamma irradiation than alpha irradiation for both ligands. Furthermore, equilibration with nitric acid did not have a significant impact on ligand degradation for either irradiation source. Identified degradation products were similar for both gamma and alpha irradiation and occurred mostly through the rupture of the N–Ccarbonyl and C–Oether bonds for T2EHDGA and the C–Oether bond in HEH[EHP]. Acid contact appears to alter the degradation pathway by favoring the formation of higher molecular weight recombination products. Mixed T2EHDGA-HEH[EHP]-NO3 complexes were formed with Nd(III) after extraction from 3 M HNO3, and low LET gamma irradiation of the Nd(III) loaded organic solution produced similar degradation products as the organic solution absent of Nd(III). Interestingly, and likely due to the greater radiolytic susceptibility of T2EHDGA than HEH[EHP], a HEH[EHP]-Nd(III) complex appears to form as the T2EHDGA degrades with increasing absorbed dose.
Original language | English |
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Pages (from-to) | 449-482 |
Number of pages | 34 |
Journal | Solvent Extraction and Ion Exchange |
Volume | 41 |
Issue number | 4 |
DOIs | |
State | Published - 2023 |
Funding
This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under contract [DE-AC52-07NA27344].
Funders | Funder number |
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U.S. Department of Energy | |
Lawrence Livermore National Laboratory | DE-AC52-07NA27344 |
Keywords
- ALSEP
- gamma irradiation
- gamma irradiation
- radiolysis
- solvent extraction