GREENCDT Development of an in-situ monitoring tool for Actinides ions

The safe characterisation, retrieval, and treatment of materials both during processing and for the purposes of decommissioning is a major challenge faced by the nuclear industry. For example, decommissioning of plants such as high hazard ponds present at a number of civil nuclear sites (e.g. Sellafield, Harwell, Winfrith) requires the full and accurate characterization of the supernatant with minimum involvement from human operators to minimise their radiological exposure. Likewise, fuel reprocessing in countries employing closed fuel cycles would benefit from the fast and in-situ monitoring of key actinide ions such as Uranium, Neptunium and Plutonium to help track progress of extraction stages. A device capable of in-situ analysis of those environments is therefore desirable.

The Micro-Optical Ring Electrode (MORE) is a photo-electrochemical sensor consisting of a central fibre optic light guide, which allows for the delivery of light to the test environment, triggering a series of photochemical reactions and a concentric gold ring microelectrode capable of detecting the very small amounts of the products of those photochemical reactions.

A mathematical model exists that correlates the electrochemical signal output to the concentration of the analyte present in the bulk solution. Previous studies in model systems have shown that the MORE is capable of distinguishing analyte based on their (i) photophysical and (ii) electrochemical properties and can therefore be used as a multi-analyte characterisation tool.

This project builds on previous work to further our understanding of the behaviour of the MORE in mixtures, extract key photophysical and electrochemical parameters of actinide target analytes and develop a standard operating procedure for multiple analyte detection. Experimental work will be conducted in inactive and active facilities on the Lancaster campus as well as through the NNL Academic Access procedure.