X-ray electron investigation of samples of fuel-containing masses formed as a result of Chernobyl NPP accident

Method of X-ray electron spectroscopy was used to analyze six samples (1-6) of fuel-containing masses (FCM), formed in result of Chernobylsk-4 reactor accident. It was established that ions of elements (U, Zr, Si, N, C) in analyzed samples were in chemically nonequilibrium states, typical for different oxidation degrees. Relative percentage of uranium ions of different oxidation degrees in analyzed FCM samples was determined. It was revealed, that samples 1-4 represented melts of oxygen-containing compounds, including additional ions of elements with lower oxidation degree, as compared to the most stable oxides (ZrO2, SiO2, UO2 etc). It is noted that intensive chemical processes of further oxidation of uranium ions and ions of after elements with release of heat can take place in result of contact with air and rain water. This fact should be taken into account when monitoring neutron fluxes and at temperature control of nuclear fuel. 9 refs., 2 figs., 1 tab