Radioactivity distribution in fuel-containing materials (Chernobyl “lava”) and aerosols from the Chernobyl “Shelter”

Homogeneity of the radioactivity distribution, composition and structure of radioactive phases were investigated for several samples of Chernobyl fuel-containing materials (Chernobyl “lava”) collected in different parts of the destroyed reactor building. The spatial distribution of the α- and of the total activity is homogeneous on the scale of tens microns. XAFS results suggest that the major fraction of U is dissolved in a glassy matrix. At the same time, SEM-EDX and X-ray tomography reveal a high concentration of inclusions and bubbles in the lava samples. The process of lava disintegration continues with different rates depending on environmental conditions around a particular lava stream in the reactor building.