Characterising legacy spent nuclear fuel pond materials using microfocus X-ray absorption spectroscopy.
Analysis of a radioactive, coated concrete core from the decommissioned, spent nuclear fuel cooling pond at the Hunterston-A nuclear site (UK) has provided a unique opportunity to study radionuclides within a real-world system. The core, obtained from a dividing wall and sampled at the fill level of the pond, exhibited radioactivity (dominantly (137)Cs and (90)Sr) heterogeneously distributed across both painted faces. Chemical analysis of the core was undertaken using microfocus spectroscopy at Diamond Light Source, UK. Mapping of Sr across the surface coatings using microfocus X-ray fluorescence (μXRF) combined with X-ray absorption spectroscopy showed that Sr was bound to TiO2 particles in the paint layers, suggesting an association between TiO2 and radiostrontium. Stable Sr and Cs sorption experiments using concrete coupons were also undertaken to assess their interactions with the bulk concrete in case of a breach in the coating layers. μXRF and scanning electron microscopy showed that Sr was immobilized by the cement phases, whilst at the elevated experimental concentrations, Cs was associated with clay minerals in the aggregates. This study provides a crucial insight into poorly understood infrastructural contamination in complex systems and is directly applicable to the UK's nuclear decommissioning efforts.
Research Centre for Radwaste Disposal, School of Earth and Environmental Sciences, The University of Manchester, Oxford Road, Manchester M13 9PL, UK; National Nuclear Laboratory, Chadwick House, Warrington Road, Birchwood Park, Warrington, WA3 6AE, UK; Centre for Radiochemistry Research, Chemistry Building, The University of Manchester, Brunswick Street, Manchester M13 9PL, UK.
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Bower
Research Centre for Radwaste Disposal, School of Earth and Environmental Sciences, The University of Manchester, Oxford Road, Manchester M13 9PL, UK.
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Morris
Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, UK.
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Mosselmans
National Nuclear Laboratory, Chadwick House, Warrington Road, Birchwood Park, Warrington, WA3 6AE, UK.
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Thompson
National Nuclear Laboratory, Chadwick House, Warrington Road, Birchwood Park, Warrington, WA3 6AE, UK; School of Chemical Engineering and Analytical Science, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK.
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Banford
Centre for Radiochemistry Research, Chemistry Building, The University of Manchester, Brunswick Street, Manchester M13 9PL, UK.
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Law
Research Centre for Radwaste Disposal, School of Earth and Environmental Sciences, The University of Manchester, Oxford Road, Manchester M13 9PL, UK. Electronic address: richard.pattrick@manchester.ac.uk.
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Pattrick
Concrete; Contamination; Decommissioning; Legacy materials; Microfocus spectroscopy; Spent fuel pond; X-ray absorption