三门湾宁波区域核电站运行前放射性本底的监测分析

Monitoring and analysis of radioactive background in Ningbo area of Sanmen bay nuclear power plant before operation

目的了解三门湾宁波区域核电站运行前环境辐射水平和环境介质放射性水平,建立环境本底分布基线资料。方法通过现场监测和实验室检测获取核电站宁波区域30 km范围内环境γ外照射剂量率和生物介质(水源水、农产品、水产品和晨尿)的放射性水平基线数据。结果原野环境γ外照射剂量率的平均值为86.47 n Gy/h±5.25 n Gy/h,距核电站10 km监测区域环境γ外照射剂量率低于10 km以上的区域。不同季节原野γ外照射剂量率比较差异无统计学意义(P>0.05)。居民晨尿中放射性核素3H和137Cs监测值分别为1.716 Bq/L±0.654 Bq/L和1.037 Bq/L±0.038 Bq/L,农产品检出值均远小于国家标准中对食品中放射性物质的限值要求,水源水样品总放射性指标符合国家饮用水标准。结论建立监测区域核电站运行前放射性本底背景值,为核电站运行后三门湾宁波区域的长期监测和数据比对提供参考。

Objective To understand environmental radiation level and the environmental medium radioactivity level in Ningbo area of Sanmen bay nuclear power plant before operation, establish baseline data of environmental background distribution. Methods Obtain baseline data for terrestrial γ radiation dose rate and radioactivity levels of biological media （ source water, agricultural products, aquatic products and human＇ s morning urine specimens） through field monitoring and laboratory testing. Results The average γ external exposure dose rate in the field environment was 86.47 nGy/h ＋ 5.25 nGy/h. The average external exposure dose rate within 10 km of the regional was less than regions of 10 km away. There was no significant difference in the dose rate of γ radiation in the different seasons （ P 〉 0.05 ）. Radionuclides monitored values of 3 H and 137 Cs were 1. 716 Bq/L ＋ 0. 654 Bq/L and 1. 037 Bq/L ＋ 0. 038 Bq/L in residents morning urine; the radioactive detection values of agri- cultural products are far less than the national standard, and the total radioactive indicators of source water samples meet the national drinking water standards. Conclusion Establishing baseline data for the radioactive background before operation in Ningbo area of Sanmen bay nuclear power plant can provide reference for long - term monitoring and data comparison after operation in Ningbo area of Sanmen bay nuclear power plant.