美国内陆核电厂放射性液态流出物累积影响的评估

Long Term Cumulative Radiological Impact Assessment to Liquid Effluent of American Inland NPPs

调研美国38个典型内陆核厂2005—2011年的环境监测资料,分析其液态放射性流出物受纳水体沉积物中放射性核素浓度水平。研究表明,近年来美国内陆核电厂运行排放的液态放射性流出物未对受纳水体沉积物造成明显的累积影响,少数核电厂在局限于厂址排放口附近或局域范围内检测到来自核电厂排放的放射性物质,而这些放射性物质与沉积物中的天然放射性核素浓度相比,是非常微量的,个别核电厂监测到来自核电厂排放的放射性核素浓度略高,与核电厂受纳水体水文条件较差有关。岸边沉积物外照射剂量估算结果表明,公众受核电厂排放液态放射性物质造成的剂量水平与美国公众受到的天然本底辐射剂量水平以及NRC对核电厂流出物规定的剂量约束值相比是可以忽略的。相应结论可为我国内陆核电厂的选址、建设和运行提供参考借鉴。

The annual radioactivity monitoring reports （2005--2011） for 38 typical inland nuclear power plants in US were investigated, and the artificial radioactivity levels in the sediments of receiving water of liquid effluent were analyzed. It was indicated that the long term operation of these NPPs had no obvious cumulative impacts on sediment, only at a few of which were found radioactivity originated from liquid effluents around discharge points, and much lower than the natural radioactivity concentrations. Only a very few NPPs had an effect with relatively higher concentration levels of radioactivity in sediment, which was due to the poor hydrological conditions of the receiving water for the dilution of radioactive liquid effluents. According to the dose assessments of artificial radioactivity in sediment to public individuals, all American typical inland NPPs had negligible impacts on public health compared to the natural public background and the personal dose constraint of liquid effluent regulated by NRC.