Dominic Maertens, Koen Binnemans and Thomas Cardinaels of the Dept. of Chemistry, KU Leuven, have published a new article entitled Demonstration of Uranium(VI)/Plutonium(IV) Separation via Solvent Extraction by D2EHiBA in Annular Centrifugal Contactors. The article is published in the journal Solvent Extraction and Ion Exchange.
The use of N,N-dialkylamides as alternatives for tri-n-butyl phosphate (TBP) as extractants in the reprocessing of spent nuclear fuel has been investigated since the 1960s. N,N-di-2-ethylhexyl isobutyramide (D2EHiBA) and N,N-di-2-ethylhexyl n-butyramide (D2EHBA) can selectively extract hexavalent and tetravalent actinides from nitric acid spent nuclear fuel solutions. Annular centrifugal contactors (ACCS) have been designed specifically for counter-current multi-stage solvent extraction in the nuclear sector. Their main advantages are a high stage efficiency, the ability to work at short residence times (seconds), and a small liquid hold-up. In the present study, a new D2EHiBA-based separation of hexavalent uranium from tetravalent plutonium was investigated using ACCs, where for safety and practical reasons the use of hydrazine or other reductant/complexant is avoided altogether. The extraction behavior of technetium-99 m, ruthenium-103, and americium-241 was also monitored under those process conditions. It was demonstrated that uranium(VI) can be quantitatively extracted and purified from plutonium(IV) using the D2EHiBA extractant. A U(VI)/Pu(IV) decontamination factor of more than 6000 was obtained. The excellent performance of the modified lab-scale BXP012 annular centrifugal contactors was demonstrated, and these contactors have proven to be a valuable tool in the upscaling of solvent extraction processes at the Belgian Nuclear Research Center (SCK CEN).
Reference
Maertens, D., Binnemans, K., & Cardinaels, T. (2024). Demonstration of Uranium(VI)/Plutonium(IV) Separation via Solvent Extraction by D2EHiBA in Annular Centrifugal Contactors. Solvent Extraction and Ion Exchange, 1–15. https://doi.org/10.1080/07366299.2024.2440495
Acknowledgement
The authors would like to thank Jolan De Peuter for synthesis and purification of the D2EHiBA extractant and assistance in performing the solvent extraction experiments, Felice Mastroleo for Q-ToF QC measurements of D2EHiBA, Bart Van Houdt for producing 103Ru at the BR1 reactor, Melissa Crabbé for coordinating the 99mTc shipment from the hospital of Geel, and Jef Leysen for the design and engineering work on the BXP012 annular centrifugal contactors.
