压水堆核电厂源项控制实践与改进

本文分析了福清核电厂1号机组停堆沉积源项调查发现的一回路管道内壁⁵⁸Co和⁶⁰Co表面活度水平、剂量率贡献以及随机组运行时间发生的变化情况,并介绍了压水堆核电厂活化腐蚀产物的形成、沉积及存在形式。通过分析201大修主泵停运对氧化运行效果及蒸汽发生器(SG)下封头辐射水平的影响,结合酸性氧化环境下腐蚀产物溶解度变化的特点,提出改进主泵停运时机以提高氧化运行效果的建议。另外,还分析了阀门密封面维修导致向一回路系统引入含钴金属颗粒对机组源项的影响,建议严格控制阀门维修过程以减少⁵⁹Co进入一回路系统。

Practice and improvement of source term control in a PWR nuclear power plant

According to the investigation of outage deposition source term of Unit 1 of Fuqing NPP, the surface activity, dose-rate contribution of ⁵⁸Co and ⁶⁰Co on the inner wall of primary loop pipeline and their variation with time are analyzed. Meanwhile, the formation, deposition and existence form of activated corrosion products in this PWR are introduced. By analyzing the influence of the main pump shutdown on the oxidation operation effect and the radiation level of the SG channel head during the outage 201, combined with the characteristics of the solubility change of the corrosion products in the acidic oxidation environment, a suggestion for improving the shutdown timing of the main pump to improve the oxidation operation effect is proposed. In addition, the influence on source term by the introduction of cobalt metal particles into the primary loop system caused by valve seal face maintenance is analyzed. It is suggested that strict measures should be taken to control the valve seal face maintenance process to reduce ⁵⁹Co entering into the primary loop system.