Physical rationality of the universal model of radioactive depositions after the Chernobyl accident

A possibility of developing a universal model for the Chernobyl depositions is substantiated. The model relates radionuclides specifications and correlation ratios of activities in depositions and characteristics of preaccidental fuel and the accident circumstances. Within the model, consideration is given to two main groups of radionuclides in terms of their volatility. One group consists of non-volatile refractory radionuclides (zirconium, niobium, cerium, europium, neptunium, plutonium) and the second - radionuclides having both fuel and free activity components in the depositions (cesium, strontium, antimony, ruthenium, barium and others). The physical and chemical differences in the two deposition species dictate the search of regularities in formation of each of them, in particular deriving correlation ratios of radionuclides in the fuel and condensation components of the radioactive contamination.