[en] It is determined that two types of high-active particles are characteristic for the nearest zone of the Chernobyl NPP (up to 4-5 km) and for western trace of fall-outs equal to 20 km distance from the damaged unit. The first one consists of particles of the irradiated fuel, the second type - substances containing uranium and zirconium oxides. The second type is more characteristic for the nearest zone and minor degree of leaching is observed here. One should expect primary disintegration of first type particles into microunits of readily migrating hot particles