Non-destructive characterisation of low radioactive particles from Irish Sea sediment by micro X-ray synchrotron radiation techniques: micro X-ray fluorescence (mu-XRF) and micro X-ray absorption near edge structure (mu-XANES) spectroscopy

Three radioactive uranium- rich particles were isolated from an Irish Sea sediment core using solid state nuclear track detection. Bulk analysis of the 24 - 26 cm core layer showed environmentally significant Pu and Am activities and concentrations. Morphology, elemental composition and uranium oxidation states of the particles were studied with electron microscopy and X- ray applications mu- XRF and mu- XANES. The results indicated that two of the particles were nuclear fuel debris, and one of them was of natural origin. The uranium in the particles was found to be in two oxidation states at different percentages: 60 - 66% as U-IV and 34 - 40% as U-VI.