Forecasting the Radiation Situation and External Exposure of Forestry Workers at a Soil Pollution Density of ¹³⁷Cs 37-185 kBq/m²

Introduction. Thirty-five years after the Chernobyl accident, approximately 662 thousand hectares of forest plantations in the Russian Federation are growing in the areas affected by radioactive contamination, which requires ensuring radiation safety in forestry operations. The purpose of the study is to predict the radiation situation and external radiation doses to workers in forest plantations where the ¹³⁷Cs contamination density of soil varies within the range of 37–185 kBq/m². Objects and methods. The object of the study is a conditional district forestry that has an area of 10,000 hectares and includes 100 forest compartments. The density of soil pollution with ¹³⁷Cs was modeled in the range from 50 to 180 kBq/m². For the 2024 to 2084 period, forecast calculations of the density of soil pollution with ¹³⁷Cs were made along with the distribution of forest compartments according to the zones and subzones of radioactive contamination, the ambient dose equivalent rate of external gamma radiation, and the radiation dose to workers. Results. It has been established that by 2054, 7,700 hectares will be located on the territory of the district forestry with the ¹³⁷Cs contamination density of soil varying from 37 to 74 kBq/m². By 2084, around 80 per cent of the territory will have been categorized as conditionally uncontaminated, the density of soil contamination with ¹³⁷Cs ranging from 18 to 37 kBq/m². Conclusion. In the district forestry plantations, the inter-compartment interval of the ambient dose equivalent rate of external gamma radiation is predicted to decrease from 95–125 nSv/h in 2024 to 50–60 nSv per hour in 2054, and to 25–35 nSv per hour in 2084. The range of the external radiation dose to workers will decrease from 0.12–0.15 mSv per year in 2024 to 0.03–0.04 mSv per year in 2084, which is more than six times lower than the national Radiation Safety Standards NRB-99/2010. Radiometric control of by-use products is recommended at the ¹³⁷Cs contamination density of soil varying within the range of 18–37 kBq/m².