According the design documentation for the Chernobyl NPP Cooling Pond (CP) decommissioning a forecast of possible radioactive contamination of the territory of Belarus and Russia due to radionuclides resuspension followed a tornado passage over the CP drained part are made. The calculations were performed using a set of models, including the conceptual model of a tornado, the mesoscale atmospheric diffusion model of pollutant transport LEDI and dosimetric models. The activity raised by a tornado vortex of intensity F3 from the CP drained part was assessed as 13.9 TBq 137Cs, 2,47 TBq 90Sr, 0.0248 TBq Pu. Depending on the chosen meteorological scenario an maximal additional density deposition on the territory of Belarus (in Polesye State Radiation Ecological Reserve) was assessed as 35 kBq m-2 137Cs, 6 kBq m-2 90Sr and 0,06 kBq m-2 Pu, whereas in the nearest settlements of Belarus and Russia - 5 - 9 kBq m-2 137Cs, 1.0 - 1.7 kBq m-2 90Sr and 10 - 17 Bq m-2 Pu, i.e. it isn't exceed 1-2 % of the actual one. The radiation dose to the people of Belarus will not exceed 1 mSv, Russia - 10-2 mSv. Hence, the safety analysis showed that a tornado passage over the CP will not result in an unacceptable dose to individuals in Belarus and Russia.
Keywords: cooling pond of the Chernobyl nuclear power plant, tornado, radionuclides atmospheric transport model, radioactive aerosols, transboundary transport.
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