中国核动力院核基地外围空气CO2中14C分布特征及所致公众年有效剂量评价

基于2014—2017年中国核动力院核基地外围环境空气中¹⁴C的监督性监测数据,对关键居民组各种途径的待积有效剂量进行了粗略的估算。结果表明:综合楼与南坝工会空气中¹⁴C活度浓度差异有统计学意义,综合楼与木城水厂空气中¹⁴C活度浓度差异有统计学意义,南坝工会与木城空气中¹⁴C活度浓度差异无统计学意义,表明排放出来的¹⁴CO₂在空气中扩散混合很快。综合楼附近居民组中成人、青少年、儿童、幼儿经各途径的¹⁴C年平均摄入量分别为40.55、40.52、29.10、19.80 kBq/a;年待积有效剂量分别为23.31、22.91、23.08、19.44 μSv/a。其中成人组成员所受¹⁴C致待积有效剂量最大为23.31 μSv/a,但此待积有效剂量也仅占评价剂量目标值(0.25 mSv)的9.3%以下。由此可以得出,核基地核施设正常运行工况下,¹⁴C对核基地外围环境的影响很小。

Distribution characteristics of 14C in the ambient air (CO2) of the nuclear base of China Nuclear Power Institute and annual effective dose evaluation for the public

Based on the monitoring data of ¹⁴C in the surrounding air of the nuclear base of China Nuclear Power Institute, from 2014 to 2017, the effective dose to be accumulated for key residential groups in various ways was roughly estimated. The conclusion shows that the difference of ¹⁴C activity concentration in the air between the comprehensive building and the labor union of Nanba is statistically significant; the difference of ¹⁴C activity concentration in the air between the comprehensive building and the water works of Mucheng is statistically significant; while the difference of ¹⁴C activity concentration between the labor union of Nanba and the water works of Mucheng is not statistically significant. The above discussed results indicat that emitted ¹⁴CO₂ diffuses and mixes rapidly in the air. The average annual ¹⁴C intakes of adults, teenagers, children and children in the residential groups near the comprehensive building were 40.55,40.52,29.10 and 19.80 kBq/a, respectively, and the relevant annual effective doses to be accumulated were 23.31, 22.91, 23.08 and 19.44 μSv/a. The maximum effective dose of ¹⁴C in adult group was 23.31 μSv/a, but it only accounted for 9.3% of the target dose (0.25 mSv). It can be concluded that the influence of ¹⁴C on the surrounding environment of nuclear base is very small under normal operation conditions of the nuclear base.