The PDRA project will seek to develop laser-based methods for characterisation of degraded spent nuclear fuel materials in situ. The techniques, including time-resolved laser fluorescence (TRLFS), Raman and laser-induced breakdown (LIBS) spectroscopy, provide direct speciation, structural and compositional information on uranium-containing compounds and solutions. Moreover, they offer the potential for ‘hands-off’ deployment, which is essential in high dose environments.
The corrosion of spent nuclear fuel leads to poorly defined, amorphous and non-stoichiometric solid phases together with colloidal suspensions and actinide-containing solutions, typically of high pH, as is the case with Magnox ponds. Fluorescence spectra and decay lifetimes of uranium (and several other species, such as europium and curium) are hypersensitive to the type and number of ligands surrounding the actinide ion, enabling identification of the species on thin films or in solution down to millimolar concentrations. State of the art TRLFS and Raman systems have been established at UoS and a LIBS capability is being developed. The set-up is sufficiently flexible to allow corrosion or mixing experiments to be conducted online and in real time. Substantial effort is now required to compile a comprehensive database that will provide a characterisation profile unique to each species. Type mineral samples on loan from national reference collections together with bespoke samples prepared at UoS and partner laboratories are being used to derive the necessary data.
The feasibility of in-situ deployment will be explored in collaboration with the University of Bristol who have extensive experience with miniaturised fibre-optic coupled probes. The Bristol group (Scott/Springell) is also capable of supplying single-crystal thin films of U phases with a precisely defined surface orientation.
Academic Lead: David Read
Researcher: Victoria Frankland
Location: University of Surrey