压水堆核电厂液态流出物中55Fe的排放与监测方法

本文调研分析压水堆核电厂液态流出物中排放⁵⁵Fe的来源、排放的统计参考值和⁵⁵Fe的分析方法,提出开展核电厂液态流出物中⁵⁵Fe监测的建议。统计分析了美国41座压水堆核电厂在2005～2017年液态流出物中⁵⁵Fe的排放量,其发电量归一化排放量的几何平均值范围为5.18×10^-6～8.14×10^-5 GBq/GWh,所有压水堆电厂液态流出物中⁵⁵Fe排放量的几何平均值为1.52×10^-5 GBq/GWh,各年度⁵⁵Fe排放量在液态流出物中占比在12%以上,排第1至第4位。根据我国典型压水堆核电厂液态流出物排放体积,估算了液态流出物中⁵⁵Fe的排放浓度,约10.7 Bq/L。建议推进核电厂液态流出物中⁵⁵Fe监测方法的建立和完善。通过对⁵⁵Fe监测方法的调研,推荐采用固相萃取树脂的快速分析方法。

An investigation on discharge and analytical methods of 55Fe in liquid effluents from PWRs of nuclear power plants

This paper focuses on sources investigation of ⁵⁵Fe in liquid effluents from pressurized water reactors (PWRs) in nuclear power plants and relative analytical methods and provides some suggestions on development of ⁵⁵Fe monitoring in liquid effluents of nuclear power plants. The discharge amounts were statistically analyzed by extracting the data from public annual effluent reports of 41 US PWRs during 2005-2017 (total 871 reactor-years), which would help us to understand the necessity of ⁵⁵Fe monitoring in liquid effluents in discharge supervision of nuclear power plants. The statistical results showed that the electricity normalized discharge amounts (geometric averages) for each PWR mainly ranged from 5.18×10^-7 to 8.14×10^-5 GBq/GWh with an average of 1.52×10^-5 GBq/GWh, with above 12% of the total fission and activation radionuclides which ranked from the first to the forth. From a typical discharge volume of a Gigawatt scale PWR, the estimated discharge concentration of ⁵⁵Fe about 10.7 Bq/L would be deduced. Meanwhile, the analytical methods of ⁵⁵Fe were extensively investigated and the monitoring method standardization of ⁵⁵Fe in liquid effluents is suggested, especially for a rapid analytical method of chromatography separation and liquid scintillation measurement.