大连市区地表天然放射性水平调查  

INVESTIGATION ON THE NATURAL RADIOACTIVITY LEVEL OF GROUND SURFACE IN DALIAN URBAN AREA

作　　者：韩志滨 马宏伟[2] 杜广仁 N Zhi-bin;MA Hong-wei;DU Guang-ren(No.240 Institute of Nuclear Industry,Shenyang 110032,China;Shenyang Center of China Geological Survey,Shenyang 110034,China)

机构地区：[1]核工业240研究所,辽宁沈阳110032 [2]中国地质调查局沈阳地质调查中心,辽宁沈阳110034

出　　处：《地质与资源》2020年第5期483-489,共7页Geology and Resources

基　　金：中国地质调查局项目“大连海岸带陆海统筹综合地质调查”(编号DD20189504).

摘　　要：利用ARD型γ能谱仪对辽宁省大连市区地表天然放射性核素238U、232Th、40K含量进行了现场测量.调查结果显示,大连市区238U、232Th、40K比活度平均值分别为23.09 Bq/kg(范围值1.24~151.91 Bq/kg)、18.99 Bq/kg(范围值0.41~92.57 Bq/kg)、386.39 Bq/kg(范围值31.30~1095.50 Bq/kg),均显著低于全国和世界的平均值.在测得的238U、232Th、40K含量基础上,计算了距地面1 m高处空气中γ辐射吸收剂量率、外照射指数、内照射指数和年有效剂量等参数,并据此对大连市区天然放射性水平进行了评价.空气中γ辐射吸收剂量率(Dr)平均值为39.04 nGy/h,远低于全国(81.5 nGy/h)和世界(80 nGy/h)平均水平.外照射指数、内照射指数平均值分别为0.23、0.12,均远小于国家对建筑材料外照射指数的限值1.年有效剂量为0.048 mSv,远低于世界年平均有效剂量(0.46 mSv)以及公众外照射年有效剂量(1.0 mSv)的限值.评价结果表明,大连市区地表天然放射性辐射处于安全的水平.The contents of natural radionuclide such as 238U,232Th and 40K on the ground surface of Dalian City,Liaoning Province,are surveyed with the ARDγ-ray spectrometer.The results show that the average specific radioactivity of 238U is 23.09 Bq/kg(ranging from 1.24 to 151.91),232Th 18.99 Bq/kg(0.41-92.57),and 40K 386.39 Bq/kg(31.30-1095.50),which are all significantly lower than the national and world averages.On the basis of measured radionuclide concentration,the parameters including the absorbed dose rate ofγradiation(Dr)at 1 m above the ground,external exposure index(Ir),internal exposure index(IRa)and annual effective dose(Daed)are calculated,and then the natural radioactivity level are evaluated.The average Dr of 39.04 nGy/h is far lower than the national average(81.5 nGy/h)and world average(80 nGy/h).The average values of Ir and IRa are 0.23 and 0.12 respectively,much less than the national limit(1)for external exposure index of building materials.The Daed of 0.048 mSv is far below the world average annual effective dose(0.46 mSv)and limit of annual effective dose for external public exposure(1.0 mSv).The evaluation results show that the natural radioactive radiation of surface in Dalian urban area is at a safe level.

关 键 词：天然放射性核素 天然放射性水平 外照射指数 年有效剂量 大连市 

分 类 号：P631.6[天文地球—地质矿产勘探]