Physico-Chemical Characterisation of Inhalable MOX Particles According to the Industrial Process

The physico-chemical properties of inhalable MOX powders made according to two different industrial processes (COCA and MIMAS) have been characterised. This was done using both a Scanning Transmission Electron Microscope (STEM) at 200 kV interfaced with Energy Dispersive X ray Spectrometry (EDS), and autoradiography. For particles containing more than 2% (w/w) Pu/U+Pu, EDS showed heterogeneity in the physico-chemical composition due to the presence of both single particles of 'pure' UO 2 , 'pure' PuO 2 , mixed oxides at different Pu/U+Pu ratios, and the presence of aggregates. The presence of Pu in particles containing less than 2% Pu/U+Pu, was estimated from quantitative autoradiography and shows more than 25% of the particles emitting α tracks contained less than 0.4% Pu.