Characteristics Of Radon Exhalation And Analyses Of Radiation Dose From Some In-situ Leaching Uranium Mine Of Xinjiang

Compared with traditional uranium mining, in-situ leaching uranium mining technology reduces the pollution of tailings dam and waste rock on the ground, has obvious advantages in environmental protect, but the impact on the environment has its own characteristics, which the effect of radiation can not be ignored and brings uranium workers and the public to potential radiation risk, caused by the process of radon exhalation from in-situ leaching uranium, the exposure pathway is internal radiation, which forms a long-term radioactive hazard. Therefore, study on characteristics of radon exhalation and analyses of radiation dose from in-situ leaching uranium, in order to provide scientific basis for radiation protection of in-situ leaching uranium, which is of great significance to protect the environment and the health of people.In this paper, some in-situ leaching uranium was taken as research object, the radon concentrations and radon exhalation rate in the ambient air were investigated and measured through in-situ leaching uranium, The distribution of radon concentration values, public individual dose, public collective dose as well as the 5 kilometers range of public individual dose equivalent in each area at the range of 20 kilometers around, caused by leaching pool and evaporation pool, were simulated by utilizing UAIR-FINE, and analysis of the influence of radon exhalation around the staff and the public. There are some conclusions as following:(1)The radon measurements showed that the measured values were below the standard of constraint value, the hydrometallurgy workshop on the second floor of radon concentration was significantly higher than other floors, maximum of radon concentration was 438Bq/m3, the second floor of liquid and uranium solution in the adsorption tower were most, it easily lead to radon release; the main sources of radon exhalation are leaching pool in the in-situ leaching uranium mine, and the increase of temperature can promote radon exhalation on the surface of the leaching liquid; Through safety estimation, the amount of radon in the in-situ leaching uranium mine is far less than that of the traditional mine.(2)The maximum personal radiation dose of hydrometallurgy workshop on staff was estimated at about 2.01 m Sv/a, lower than the national standard limit, and the radiation dose has little impact for staff.(3)The results of radon concentration and dose distribution showed that, the radon concentration was reduced as the increase of the distance in the same direction, and when the distance was within 5 kilometers, the descend gradient was comparatively large; Due to the influence of wind frequency, the public dose equivalent line is dispersed in the west and northwest, and the descend gradient was comparatively small; The leaching pool and evaporation pool are located on the downwind of the prevailing wind direction, the residential area are located on the upwind, and the residents of the downwind are located 10 km outside, Uranium mine reduced the impact of pollution for public by reasonable geographical layout. The maximum of radon concentration and individual dose all appeared in the W orientation of the leaching pool, the maximum public individual dose of residential areas were A village and the value was 0.00171 m Sv/a, which located in the east of leaching pool and within 2 to 3 kilometers; Moreover, the public collective dose was 4.55×10-3Sv/a, the values were lower than standard limit, and it has little influence for public with meeting the requirements of radiation protection.(4)According to the characteristics of the in-situ leaching uranium, reasonable suggestions of radon exhalation were proposed.