西安灞桥燃煤电厂周围土壤天然放射性水平

Natural Radioactivity Level in Soil Around Baqiao Coal-fired Power Plant

应用低本底多道γ能谱仪测定了燃煤电厂周围土壤中天然放射性核素226Ra、232Th和40K的比活度,评价了其辐射危害。测定结果表明,土壤中226Ra、232Th和40K的比活度分别为27.60～48.78、44.39～61.39和640.19～992.25 Bq/kg,平均值分别为36.07、51.13和733.91 Bq/kg。电厂周围土壤中226Ra比活度大于陕西土壤平均水平,稍小于全国土壤平均值;232Th和40K比活度均大于陕西省土壤和全国土壤平均水平。在距离电厂1 000 m范围内,土壤中226Ra和232Th无明显空间差异,而40K比活度在距电厂100 m处土壤中明显低于400 m和1 000 m处。等效镭活度、空气吸收剂量率和年有效剂量率评价结果表明,燃煤发电对灞桥电厂周围土壤放射性有一定影响,但放射性水平处于正常。

Natural radioactivity in soil around Baqiao coal - fired power plant had been measured by using a NaI （T1） 5＇ -ray spectrometry. The results show that the specific activity of 226Ra, 232Th and 40K in soil samples ran- ges from 27.60 to 48.78, 44.39 to 61.39 and 640.19 to 992.25 Bq/kg with an average of 36.07, 51.13 and 733.91 Bq/kg, respectively. The average activity of 226Ra in soil around the power plant is greater than the av- erage of Shaanxi soil, while slightly less than the average of Chinese soil. The average activity of 232Th and 4~K in the studied soil samples are higher than the average level of Shaanxi soil and Chinese soil. The concentrations of 226Ra and 232Th in soil samples collected within 1000 m sites to coal - fired power plant boundary show no sig- nificantly spatial differences, whereas 4~K concentration in soil samples collected from 100 m sites is less than from 400 m and I 000 m sampling sites. The evaluation results of radium equivalent activity, air absorbed dose rate and annual effective dose rate show that coal -fired power plant affected the natural radioactivity level of surrounding soil, but natural radioactivity of soil is in normal level.