ABSTRACT
The phenomenon of fast radionuclide occurring in topographic depressions within the highly contaminated area of Chernobyl exclusion zone is studied by means of a three-dimensional flow and transport model. The relative increase of vertical infiltration and mass transport rate within the central part of a typical fast migration zone as compared to its background area is assessed. Observation data taken from a real depression situated within the Chernobyl exclusion zone are used for the calibration of the numerical model. Simulation results show that the role of the active zones is of fundamental importance in radioactive contamination of the upper Quaternary aquifer in the Chernobyl region.
