【摘要】 压水堆大修时活化腐蚀产物源项控制是降低集体剂量最有力的手段，冷却剂辐解的影响必须予以考虑。本文基于水辐解反应动力学原理，构建了冷却剂辐解动力学模型，根据该模型计算得到了主要辐解产物H₂O₂、O₂和H₂在各工况的生成情况，并讨论了微观反应机理。结果表明：（1）在停堆下行过程中，冷却剂温度从310℃逐步下降到60℃，溶解氢浓度逐步降为0，一回路从还原性转为氧化性，H₂O₂和O₂的生成显著上升；（2）温度、B/Li浓度、溶解氢浓度、H₂O₂和O₂初始浓度等多种因素均会影响辐解产物的浓度；（3）H₂O₂和O₂是相互促进生成的关系，H₂可以显著抑制H₂O₂和O₂的生成，但高浓度的H₂O₂会保护H₂免遭·OH的消耗。本文研究结果将为压水堆大修下行工况参数的选择以及活化腐蚀产物源项控制提供参考和指导。更多还原

【Abstract】 The control of radioactive source of the activated corrosion products during the shutdown of PWRs is one of the most effective means to reduce the CRE. The effect of coolant radiolysis should be taken into account. In this paper, a coolant radiolysis kinetic model was developed based on water radiolysis reaction kinetics. The main radiolysis products such as H₂O₂, O₂ and H₂ under different conditions were obtained through the kinetic calculations. The reaction mechanism was also discussed. The results showed that:（1） during the shutdown, as the temperature of coolant decreases from 310℃ to 60℃, and the concentration of dissolved H₂ decreased to 0, the coolant changes from reductive to oxidative. The radiolysis generation of H₂O₂ and O₂ is significantly promoted;（2） the generation of radiolysis products is affected by the chemical parameters, such as concentrations of B/Li, dissolved H₂, dissolved O₂ and H₂O₂;（3） the generation of H₂O₂ and O₂ are mutually promoted by each other. The presence of H₂ can inhibit the generation of H₂O₂ and O₂ to some extent. The presence of high concentration of H₂O₂ will protect H₂ from the consumption of ·OH. The results in this paper may provide important references and guidances for the selection of operating parameters under different conditions during the shutdown of PWRs and the control of activated corrosion products.更多还原