Preliminary Study On Contribution Of Polonium-210in Surrounding Air By Coal-fired Power Plant

Coal palys an increasingly important role to cover the energy needs of China.More than1.3billion tons coal bruned in coal power plants every years in Chinafrom2009. It is can not be ignored that the pollution of coal-fired power plant. Andhere, the physical and chemical behavior of Po-210in high temperature processes isdescribed, that can explain how does Po-210transform, enrich and discharge duringcoal combustion. It is also predicts a stabilization of the specific activity for smallerradius of the particles up to a maximum value. UNSCEAR1993shows that theaverage enrichment factor of polonium-210on fly ash is17, specific activity is1700Bq/kg. There are a lot of papers have proved the high enrichment factor on fly ash.In order to find out the activity concentration of²¹⁰Po in air around coal-firedpower plant, the aerosol sampling plan had been worked out base on the fieldsampling conditions. Three sampling sites were chosen in this paper: two sitesaround Gao Jing coal-fired power plant and one comparative site at Radiation safetycenter in Beijing. Through literature research and experimental research, we workedout the radiochemistry processing and measurement procedures of²¹⁰Po in aerosolsamples. The aerosol samples from three sites were processed. The measuring resultof²¹⁰Po in the atmosphere of one year show, the²¹⁰Po concentration in atmospherevaried between0.079and1.37mBq/m³, with a geometric mean of0.42mBq/m³.This paper analyzed the measurement data of²¹⁰Po around coal-fired powerplant combined with meteorological data, include the temperature, wind speed, wind direction and other weather conditions. The²¹⁰Po escaped from power plant willdeposit in the wind. The measuring results from the three sampling sites show theconcentration of²¹⁰Po in winter is higher than in summer, and EML（EnvironmentalMeasurements Laboratory） data showed the similar results. Finally according to theexperimental results, we estimated the effective does according²¹⁰Po inhalation ofsurrounding residents. Effective doses of an adult caused by inhalation of²¹⁰Po is14μSv/a, a child is13μSv/a. Collective dose of the residents in shijingshan District is8.57man·Sv.In view of the coal-fired power plant emissions of²¹⁰Po, this paper do thesampling investigation and preliminary research, found that the amount of the²¹⁰Podischarged from coal-fired power plants to the environment can not be ignored. Thedetermination method of²¹⁰Po in aerosol samples and the research methods of thisarticle are laid the groundwork for further research.