Mass spectrometric determination of uranium and thorium traces in aerosols, collected over Russian territory after "Fukushima-1" accident

Secondary Ion Mass-Spectrometry was used to detect the isotopes U-238 and Th-232 in aerosols, sampled after damage of the "Fukusima-1" atomic station. The isotopes present only on the surface of the particles, so, fuel assemblages were melted, and they penetrated into environment through the gaseous phase without leakage of a solid substance in the form of primary aerosols. The presence of Th-232 is treated as a sign of U-233 production.