Chemical composition of inhalable MOX powders prepared according to a SOLGEL process: energy dispersive X-ray analysis of individual particles

Abstract We have characterized the homogeneity of inhalable (U,Pu)O 2 (MOX) powders made according to an experimental SOLGEL process by co-precipitation of soluble forms of U and Pu. These powders contained 5.3 wt.% Pu/U+Pu. In order to study inhaled particles, we have exposed rats to the MOX aerosol, and alveolar macrophages were extracted by pulmonary lavage 3 days later. Chemical analyses were performed on entire cells, using a scanning transmission electron microscope (STEM) at 200 kV interfaced with energy dispersive X-ray spectrometry (EDS). The raster analysis showed the particles contained 6.6% Pu (SD=0.9, n =20). The homogeneity was confirmed in a range of a few nanometers in each particle analysed by element mapping using a 7-nm nanoprobe. These results demonstrate that the chemical composition of the SOLGEL powders is `homogeneous' enough, so that they could be used as reference compounds for the toxicological studies after inhalation exposure to industrial MOX powder.