A Software Tool for Estimating the Absorbed Dose Rate in Pine Stands in the Case of Accidental Radioactive Fallout

The results of development of a software tool for assessing the dynamics of the absorbed dose rate of external β- and γ-radiation by the height of the pine stands during first year after accidental radioactive fallout, taking into account the dynamics of their redistribution between compartments of the “crown surface of woody plants–surface soil layer” system, are presented. The main assumptions of the software implementation using mathematical modeling methods are formulated. The estimation of radionuclide deposition on the Earth’s surface is based on the Gaussian model of atmospheric diffusion. The model (compartment) approach to the dynamics of redistribution of radionuclide activity from the composition of radioactive emissions is represented by a system of linear differential equations of the first order. The calculation of the absorbed dose rate is based on integration of the dose attenuation function of a point source. The determining contribution of β-radiation from radionuclides located on surface of the studied components of the system is established. A methodical approach that takes into account the dynamics of the distribution of radionuclides in the “crown surface of woody plants–surface soil layer” system and the associated doses of external β- and γ-irradiation by the height of pine stands during the first year after accidental radioactive fallout is implemented as a software tool and can be applied in solving problems of ensuring the radiation safety of the environment.