A probabilistic dispersion model applied to the long-range transport of radionuclides from the Chernobyl accident

Long-range atmospheric transport of radionuclides from the Chernobyl accident is modelled as an Eulerian diffusion process. From observations of the gross deposition pattern of particulate radiocaesium an effective long-range Eddy diffusivity K of the order of 106 m2 s−1 is inferred. A corresponding effective deposition length for caesium, RCs, defined as the effective distance from Chernobyl to where the aerosols have been deposited, is found to be RCs≈1000 km. From the observations of the regional variability of the Chernobyl fallout a simple probabilistic assessment method is proposed for the long-range radiological consequences of nuclear accidents