Assessment of the radiation dose rate for a terrestrial mollusk during chronic Sr-90 irradiation

摘要

Radiation dose rate for a terrestrial mollusk Fruticicola fruticum was assessed under chronic Sr-90 irradiation in field conditions by three methods. The study-site is the territory nearby the radioactive waste storage facility in the Kaluga region. Due to a loss of integrity in one of the storage capacities, there was a leakage of radionuclides in 1998. Specific activities of Sr-90 in soil, plant and shells of terrestrial mollusk used as the input parameters for calculating the radiation dose rate are: 20±3 - 5203±785 Bq/kg; 22.3±13.4 - 10596 ± 195 Bq/kg, 76±11 - 17640±2646 Bq/kg, respectively. As a result of the calculations, the following radiation dose rates were obtained: from 10±2 to 1634±245 mGy/year with the J. Levinger and L.D. Marinelli formula, from 0.012±0.001 to 2.1±0.2 mGy/year with the Erica Assessment Tool, from 0.32±0.07 to 76±9 mGy/year by the Monte Carlo method. The Monte Carlo method gives the most adequate estimates, because the application of this method allows taking into account the maximum possible scenarios of mollusk irradiation, the maximum number of input parameters, including the weight and geometry of the organism, the dosimetric and physical features of the source of irradiation.