Abstract:

This study examined the total α and total β radioactivity in aerosols surrounding the Ningde Nuclear Power Plant to investigate the spatial-temporal distribution characteristics, periodic patterns, and correlations with various influencing factors of total atmospheric radioactivity in the vicinity of nuclear power plants. Revealing the periodic patterns and coupling mechanisms of these data has significant application value for improving atmospheric environmental risk early warning systems for nuclear power plants. This study employed wavelet transformation to analyze atmospheric monitoring data around the Ningde Nuclear Power Plant and utilized the wavelet coherence spectrum to study the correlation between total α and total β radioactivity concentration and meteorological factors (precipitation and humidity), and inhalable particulate matter factors (PM_2.5 and PM₁₀). The results indicate that: 1) The total α activity concentration in aerosols around the Ningde Nuclear Power Plant was slightly higher than that of other domestic nuclear power plants, but was still within the normal environmental level range. 2) The total α and total β activity concentrations in aerosols both exhibited a primary cycle of approximately 18 months and a secondary cycle of approximately 40 months, whereas the periodicity of the total α and total β activity concentrations in aerosols around similar foreign nuclear power plants was not significant. 3) Overall, the time series of the total α and total β activity concentrations in aerosols demonstrated strong synchronicity with a positive correlation, particularly evident at medium and high frequency scales. Total α and total β exhibited negative correlations with precipitation and humidity, with conjugate cycles primarily distributed at medium and low scales. The correlation between total α, total β, PM_2.5, and PM₁₀ was not strong, particularly with no correlation observed at low scales. However, locally, total α and total β preceded PM_2.5 and PM₁₀ by approximately 1/8-1/4 cycle.

Key words: nuclear power plant, wavelet transformation, total radioactivity, influencing factors, aerosol

摘要： 以宁德核电厂周边气溶胶中总α、总β为研究对象，探讨核电厂周边大气环境总放射性的时空分布特征、周期性规律以及与各种影响因子的关联性，揭示数据的周期性规律和耦合机制，对完善核电厂大气环境风险预警体系具有重要应用价值。研究利用小波变换对宁德核电厂周边的大气监测数据进行分析，并运用小波相干谱研究了总α、总β放射性活度浓度与气象因子（降水、湿度）及可吸入颗粒物因子（PM_2.5、PM₁₀）的相关性。结果表明：1）宁德核电厂周边气溶胶中总α活度浓度监测结果较国内其他核电稍偏高，但依然处于正常环境水平范围之内；2）气溶胶总α、总β活度浓度均存在18个月左右的主周期与40个月左右的次周期，同时国外同类型的核电厂气溶胶总α、总β活度浓度周期性并不明显；3）气溶胶总α与总β间活度浓度时间序列具有较强的同步性，存在正相关关系，尤其在中、高时频尺度上这种关系较明显。而总α、总β与降水、湿度呈现负相关性，共轭周期主要分布在中、低尺度上。总α、总β与PM_2.5、PM₁₀两个因子相关性不强，尤其在低尺度上未见任何相关性，但局部总α、总β约比PM_2.5、PM₁₀提前1/8－1/4周期。

关键词: 核电厂, 小波变换, 总放射性, 影响因素, 气溶胶