中国核动力院外围空气中^(7)Be、^(40)K、^(60)Co、^(131)I、^(137)Cs分布特征及所致公众年有效剂量评价

Distribution characteristics of ^(7)Be,^(40) K,^(60)Co,^(131)I and ^(137)Cs in the ambient air of China Nuclear Power Institute and annual effective dose evaluation for the public

基于2015—2017年中国核动力院外围空气中^(7)Be、^(40)K、^(60)Co、^(131)I、^(137)Cs监督性监测数据,对综合楼、南坝工会和木城水厂监测点附近居民组三种途径的有效剂量进行了粗略估算。结果表明:随距核设施距离增加,^(60)Co、^(131)I、^(137)Cs平均年摄入量和所致年有效剂量减小;综合楼附近居民组中成人、青少年、儿童、幼儿、婴儿经吸入^(7)Be、^(40)K、^(60)Co、^(131)I、^(137)Cs平均年摄入量分别为29.25、26.48、20.16、11.49、6.79 Bq/a;综合楼附近居民组中青少年、儿童、成人、幼儿、婴儿,经吸入、浸没和地面沉积途径^(60)Co、^(131)I、^(137)Cs所致年有效剂量分别为133.58、130.98、128.61、120.20、118.61 nSv/a,^(60)Co所致剂量分数达到95.6%,其次是^(137)Cs;地面沉积途径所致剂量分数达到54%,其次是吸入;综合楼附近居民组中青少年组成员^(60)Co、^(131)I、^(137)Cs所致有效剂量最大为133.58 nSv/a,但此有效剂量也仅占评价剂量目标值(0.25 mSv)的1‰以下。由此可以得出,核基地核设施正常运行工况下,^(60)Co、^(131)I、^(137)Cs对核基地外围空气的影响很小。

Based on monitoring data of ^(7)Be,^(40) K,^(60)Co,^(131)I and ^(137)Cs in the ambient air around the China Nuclear Power Institute from 2015 to 2017,the effective doses of residents near the monitoring points of comprehensive building,Nanba Trade Union and Mucheng water plant were roughly estimated.The results showed that the average annual intake of ^(60)Co,^(131)I and ^(137)Cs as well as the induced annual effective doses decreased with the increase of the distance from the nuclear facilities;the average annual intakes of adults,teenagers,children,infants and newborns of residents near the comprehensive building by inhalation of ^(7)Be,^(40) K,^(60)Co,^(131)I and ^(137)Cs are 29.25,26.48,20.16,11.49 and 6.79 Bq/a,respectively;the annual effective doses of teenagers,children,adults,infants and newborns of residents near the comprehensive building caused by inhalation,immersion in the air and ground deposition of ^(60)Co,^(131)I and ^(137)Cs are 133.58,130.98,128.61,120.20 and 118.61 nSv/a,respectively;the dose fraction caused by ^(60)Co reached 95.6%,followed by 137 Cs;the dose fraction caused by surface deposition reached 54%,followed by inhalation;the maximum effective dose caused by ^(60)Co,^(131)I and ^(137)Cs in the youth group of residents near the comprehensive building is 133.58 nSv/a,but this effective dose is only less than 1‰of the target value of the evaluation dose(0.25 mSv).It can be concluded that ^(60)Co,^(131)I and ^(137)Cs have little influence on the ambient air of the nuclear base under normal operating conditions.