Simulation of caesium-137 (137Cs) local diffusion as a consequence of the Chernobyl accident using hotspot

The accident at the Chernobyl nuclear reactor in 1986 is considered as the most severe event that has ever occurred in the nuclear power industry, due to the considerable amounts of radioactive material released into the environment. The main purpose of this work is to simulate the dynamics of the local diffusion of caesium-137 (137Cs) in the area strictly close to the Chernobyl reactor. Among the released radionuclides, we selected 137Cs as it was responsible for most of the radiation exposure received by the general population. In order to simulate its local dispersion, HotSpot was used, being a user friendly freeware, and allowing to obtain data in terms of total effective dose equivalent (TEDE) and ground deposition. Two scenarios were simulated (General Fire and General Explosion) using boundary conditions selected from literature data. The obtained output data for the ground depositions were compared with the real ones, demonstrating that HotSpot allows for the simulation of radionuclide local release and diffusion due to the Chernobyl accident, even if only at a low scale. In fact, the relative proportions for the ground depositions values were respected and the measured TEDE values were in good agreement with the literature data.