AP1000核电站~(106)Ru正常运行源项研究

AP1000核电站一回路中~(106)Ru的现实源项远远高于其设计源项,其一回路活度浓度与131I相当,既从理论计算分析不可信,又与电厂实际测量数据不符。一回路~(106)Ru活度浓度过高,使得电厂液态流出物中106Ru及其子体~(106)Rh占到除氚和碳-14外放射性年排放量预期值的一半以上,严重背离电厂运行经验,而且对AP1000电厂流出物监测、环境监测和环境影响评价造成了误导。本文分析了ANSI/ANS-18.1中现实源项计算方法存在的问题,研究提出了从一回路主要核素活度浓度出发计算~(106)Ru现实源项的方法,其计算结果与M310/CPR1000、VVER-1000等国内压水堆电厂的现实源项基本一致,能客观反映压水堆电厂~(106)Ru源项,可供国内AP1000核电厂源项计算时参考。

A study on106Ru realistic source term of AP1000

The expected activity of 106Ru in primary coolant for AP1000 nuclear power plant is dramatically higher than its design value and reaches the same level of 131I,which is both theoretically irrational and far away from the operational experience.The deduced annual releases of 106Ru and its daughter nuclide 106Rh in liquid effluent together contribute over the half of the total releases of liquid effluent except Tritium and Carbon-14.This conclusion severely deviates from the feedback of operating plants and would mislead the effluents monitoring,environmental monitoring and environmental impact evaluation either.Here we analyze the model and parameters provided in ANSI/ANS-18.1 and develop a new approach to calculate the realistic source term of 106Ru in primary coolant from that of other key radionuclides.The results are consistent with that of other reactor types,such as M310/CPR1000 and VVER-1000,and could be referenced in plant design.