Evaluation of workers’ internal exposure because of inhalation of radioactive aerosols in a plasma melting facility by using IMBA and TAURUS codes

The bursting of gas bubbles during the melting process in nuclear decommissioning generates radioactive aerosols, causing the internal exposure of workers. In contrast to external exposure, real-time measurements and visual management cannot be applied to internal exposure cases. This study evaluated the degree of internal exposure of workers at the Kozloduy Nuclear Power Plant plasma melting facility by analyzing the data on nuclides and concentrations collected from a HEPA filter. The radiation exposure scenario was selected considering the working environment, nuclides, concentrations, working time, activity median aerodynamic diameter, and chemical form. Workers’ internal-exposure dose rates were evaluated using the IMBA (integrated modules for bioassay analysis) code.