Radiolytic degradation is an important aspect to consider when developping a ligand or a complexant for radionucleides. Diglycolamide extractants (DGAs) have been playing an important role in many partition processes...

Diglycolamide extractants, and in particular N,N,N’N’- tetraoctyl diglycolamide (TODGA), are currently under investigation for use in nuclear fuel reprocessing by liquid-liquid separations. Several processes, such as ARTIST, i-Sanex, and EURO-GANEX...

The use of microfluidics technology and the miniaturization of analytical techniques is of high interest for the chemical and nuclear industries. In the latter, the reduction of effluents deriving from actinides concentration monitoring along R&D and pilot-scale purification processes is a permanent concern. lndeed, the extremely harsh operation conditions limit the imple mentation of standard analytical techniques and methodologies, and in this regard, the use of spectrophotometric techniques for effluents characterization becomes advantageous in terms of robustness, implementation and sensitivity at the microfluidic scale. In this work, we report a study of the effect of exposure to different chemicals used in hydrometallurgical processes, and to gamma radiation typical of the Plutonium and Uranium Refining by Extraction process, on the optical and structural properties of different polymeric materials commonly used for the fabrication of microfluidic and optofluidic systems. This study shows that low-cost castable and/or engravable materials (e.g. polydimethylsiloxane and poly-methyl methacrylate) are ideal for the study and development of Photonic Lab on a Chip systems that will be used in a nuclear environment.

The radiolytic degradation of three N,N-dialkyl amide ligands relevant to nuclear fuel reprocessing was studied. The degradation of these ligands: N,N di-2-ethyhexylbutyramide (DEHBA), N,N di-2-ethyhexylisobutyramide (DEHiBA) and N,N di-2-ethyhexyl-3-dimethylbutanamide (DEHDMBA) was examined to evaluate the effect of the structure on the formation of degradation products as well as to compare alpha induced degradation to gamma induced degradation. In situ alpha radiolysis by introduction of plutonium(iv) as the alpha source in the solution and ex situ gamma radiolysis with Co as the gamma source were compared. Upon identification of the main degradation products, a degradation scheme was proposed. The effects of radiation on the stability of Pu-monoamide complexes were discussed. Theoretical calculations were also performed to determine bond dissociation energy and estimate the relative strength of the bond in the molecule. The results show that neither the type of radiation (alpha vs. gamma) nor the structure modification (introduction of branching on the alkyl chain off the carbonyl carbon) of the molecule significantly impact the formation of degradation products under the conditions studied. Moreover, it was observed that the overall stability of the monoamide remains good and that Pu complexation is not greatly affected by either alpha or gamma irradiation.

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