压水堆核电厂气态流出物环境累积效应研究

核电厂运行寿期内放射性气载流出物通过烟囱向环境排放，其中部分放射性物质会沉降并在环境中累积。为评估其累积效应，本文选取³H、¹⁴C和以气溶胶形式存在的⁸⁸Kr/⁸⁸Rb、⁶⁰Co、¹³¹I和¹³⁷Cs作为代表性核素，采用³H、¹⁴C平衡模型和气溶胶迁移扩散模型，分析了核电厂运行寿期内各核素的环境累积活度浓度。分析结果表明：代表性核素显示出了环境累积效应，绝大多数代表性核素的环境累积活度浓度远小于0.1 Bq/kg，但³H和¹⁴C的环境累积活度浓度略高，分别达2.51 Bq/kg和2.35 Bq/kg；各核素环境累积活度浓度预测结果远低于EPR-RSR给出的相应限值，不会对土地再利用造成影响；以气溶胶形式存在的放射性核素的环境浓度表现出较明显的累积增长趋势，增长趋势与半衰期和放射性核素在环境中的迁移行为相关。根据研究结果，对我国核电厂环境影响评价中典型核素的环境累积效应预测和环境监测提出了建议。

Environment Accumulation Effect from Gaseous Effluent of Pressurized Water Reactor Plant

During the operation of nuclear power plant (NPP), gaseous radioactive effluent discharges into the environment via the stack, and some of them will deposit and accumulate in the environment. In this paper, ³H, ¹⁴C and ⁸⁸Kr/⁸⁸Rb, ⁶⁰Co, ¹³¹I and ¹³⁷Cs were selected as the representative nuclides to analyze their environment accumulation effect. The result reveals the environment accumulation effect of representative nuclide. Accumulative concentrations of most nuclides are less than 0.1 Bq/kg, while those of ³H and ¹⁴C are slightly high, which are 2.51 Bq/kg and 2.35 Bq/kg respectively. Accumulative concentration of individual nuclide is still far less than relative criteria in EPR-RSR. Therefore accumulation of these nuclides in the local environment will not affect the land reuse. The environmental concentration of aerosols shows a clear cumulative growth trend which is relevant to half-life of nuclides and their migration in the environment media. Based on this study, some recommendations are put forward for the prediction of environment accumulation effects of typical nuclide and environmental monitoring for the environmental impact assessment in China.