The reprocessing of spent nuclear fuel could become safer and more efficient in future after international researchers found a way to modify the structure of molecules to remove radioactive materials.
It has been known for some time that molecules called triazines are capable of extracting minor actinides such as americium, curium and neptunium from spent nuclear fuel in a highly selective way.
However, new research led by Northumbria University in the UK has gained insights into how modifying certain parts of these molecules can influence their ability to bind to minor actinides on a molecular level.
The researchers changed the size of the aliphatic rings in the established benchmark molecules from 6-membered rings to 5-membered rings.
They found that this small but subtle change had unexpected effects on how efficiently the molecules bind and extract the minor actinides compared to the benchmark molecules.
The exact reasons for these effects were then determined at the molecular level using a range of experimental techniques.
“The findings are significant as they could allow better molecules to be designed in a more rational way, rather than simply by trial and error,” said Dr Frank Lewis, senior lecturer in organic chemistry in Northumbria University’s Department of Applied Sciences, who led the study published in Chemistry A European Journal.
“The knowledge and insights we have gained by tuning the cyclic aliphatic part of these molecules could pave the way for the rational design of improved actinide selective ligands for reprocessing spent nuclear fuels."
"Modifying these molecules in different ways to improve their extraction properties could make future reprocessing more efficient and could be essential if they are to be used industrially in future,” he added.
A paper, exploring the Subtle Effect of Aliphatic Ring Size on Minor Actinide Extraction Properties and Metal Ion Speciation in Bis-1,2,4-Triazine Ligands, has been published in Chemistry A European Journal.
The research was led by Dr Lewis with colleagues from Northumbria University (UK); the University of Newcastle (UK); the Institute of Energy and Climate Research at Research Centre Jülich (Germany); the Karlsruhe Institute of Technology’s Institute for Nuclear Waste Disposal and the Physical Chemistry Institute at Heidelberg University (Germany).
Photo: La Hague reprocessing plant in France
