Study On Movement And Deposition Of Uranium Dust In Human Respiratory Tract And Inhalation Exposure Risk Assessment

Uranium dust contains large amounts of long-lived ? radionuclides, and has high contribution rate of to internal irradiation dose. As an important parameter, mask filter efficiency is often in a neglected state in the process of internal irradiation dose calculation, and there is little research on influence of this to internal irradiation dose calculation. To explore the laws of movement and deposition of uranium dust filtered by masks in human respiratory tract and inhalation exposure risk assessment, this paper carried out researches on these questions with the human body in different respiration rate at the typical workplace in uranium mine, by combining theoretical research with experimental research. Research results are as follows,(1) the uranium dust mass concentration and size distribution data were obtained, by conducting air quality monitoring at the typical workplace in uranium mine.(2) the filtering efficiencies of two kinds of masks to PM10 and PM2.5 were tested, and the classification filtering efficiency, mass concentration and size distribution data of uranium dust filtered by masks were also obtained, by carrying out field testing of mask filtering characteristics.(3) the flow distributions within the human respiratory tract were simulated with the human body in different respiration rate, through using FLUENT software. The laws of movement and deposition of uranium dust were also simulated by using DPM model, with the data of mass concentration and size distribution data of uranium dust filtered by masks as boundary conditions.(4) the inhalation exposure risk assessment model was established and used to evaluate the inhalation exposure risk, and the inhalation exposure dose and exposure index were calculated.