Radiation chemistry at the core of the spent nuclear fuel recycling
In the current energetic context, nuclear energy plays an important role as a carbon emission abating energy source : a wave of renewed interest has been observed worldwide. To develop a clean and sustainable energy and obtain the general public acceptance, management of the nuclear waste has been optimized by recycling valuable elements such as uranium and plutonium.
Since its first industrial implementation in 1954, the PUREX (Plutonium Uranium Redox Extraction) process has been at the center of nuclear industry as a reference for spent nuclear fuel reprocessing. This process is still under development, aiming at recovering the minor actinides, but it always relies on the use of the tributylphosphate (TBP) ion in hydrocarbon solvents and nitric acid as extractant media. For further enhancement of extraction efficiency, separation factors and effective storage of nuclear waste, a predictive understanding of the radiolytic degradation of these solvents is required. This paper presents the ionizing radiation induced chemical processes on these ligands, and the issues posed by the presence of highly reactive intermediate species and/or the generation of degradation products that control for instance the solvent extraction efficiency.