Russian scientists develop organic compound to make used fuel reprocessing more efficient
13 December 2023
A team of Russian scientists from several large scientific centres have created an organic compound that helps to more effectively separate and components of used fuel during reprocessing, the press service of Lomonosov Moscow State University reported. This supports research to develop the technologies needed for the transition to a closed nuclear fuel cycle which will expand the nuclear fuel base and significantly reduce the need to mine natural uranium in large volumes. Radiochemical reprocessing of used fuel and extraction of valuable nuclear materials, primarily plutonium and uranium, is a key stage necessary for closing the fuel cycle.
A widely used method for separating chemical elements in the nuclear industry is extraction. The efficiency of the process directly depends on the selection of the extraction agent. In radiochemistry, compounds based on the nitrogen-containing polycyclic compound phenanthroline have long been used to separate used fuel components, the press release noted.
At the same time, for the extraction of metals in chemistry, macrocycles are often used – large ring molecules that can bind to a metal atom. The more closely the size of the metal particle matches that of the cavity formed by the molecular ring, the higher the selectivity – the degree of extraction of this metal from solutions.
Researchers at the Faculty of Chemistry of Moscow State University, as well as the National Research Centre Kurchatov Institute, Peoples' Friendship University of Russia and Sechenov University proposed combining two classes of compounds.
“We decided to create a new ligand in the form of a macrocycle based on phenanthroline diamides and test whether this would produce a synergistic effect,” said Ulyana Leksina, one of the authors of the work from the Department of Radiochemistry at the Faculty of Chemistry of Moscow State University. “The new compound has interesting properties: we can quantitatively carry out extraction in a highly alkaline environment, in which other known phenol-based macrocycles, calixarenes, no longer work. The selectivity also increased by 10-15 times compared with known extractants.”
She added that most research is devoted to the extraction of waste components from acidic environments, since, in the nuclear industry, used fuel is most often dissolved in nitric acid. However, some specialised enterprises store a large amount of nuclear legacy alkaline waste, which also needs to be processed. “Currently there is not much work in this direction, so our compound can become a starting point for the creation of new ligands for alkaline media,” noted Leksina.
Image: Faculty of Chemistry, Moscow State University
