【作者】 郭子方； 张扬； 李一帆； 刘春雨； 林子健； 杜香怡； 林铭章；

【Author】 GUO Zi-fang;ZHANG Yang;LI Yi-fan;LIU Chun-yu;LIN Zi-jian;DU Xiang-yi;LIN Ming-zhang;School of Nuclear Science and Technology,University of Science and Technology of China;China Nuclear Power Technology Research Institute Co.,Ltd.;

【机构】 中国科学技术大学核科学技术学院； 中广核研究院有限公司；

【摘要】 冷却剂中加入氨可以有效抑制辐解产生的氧化性物质（·OH、O₂和H₂O₂）,从而缓解结构材料的腐蚀。本文建立了含氨冷却剂辐射分解模型并验证了其可靠性,计算与实验结果的最大相对误差小于20%。使用辐解模型研究了主要因素包括温度、初始氨浓度及溶解氧浓度等对含氨冷却剂辐解行为的影响。由室温升至300℃过程中,氨分解速率大幅放缓,H₂的浓度随之降低。室温下30 ppm的氨水溶液吸收剂量为18.0 kGy时氨分解比例达到45%,而300℃下吸收剂量为8.6×10⁶ kGy时才能达到该分解比例（45%）。初始氨浓度的提升加快了氨分解速率,但降低了其分解比例,初始氨浓度由5 ppm^①增至50 ppm,分解比例从80.2%下降至40.5%（吸收剂量为1.0×10⁷ kGy）,辐解产生的H₂表现出对氨浓度降幅的线性依赖。冷却剂中存在溶解氧时,氨水的辐解过程明显加强,H₂的浓度同时降低,吸收剂量为1.0×10⁷ kGy时,无氧氨水中氨损失比例为45.5%,而溶解有8 ppm O₂的氨水溶液中氨损失率为57.9%,因此清除冷却剂中初始溶解的O₂是必要的。更多还原

【Abstract】 Ammonia added in the reactor’s primary circuit can effectively suppress the oxidizing substances（·OH,O₂,and H₂ O₂） produced by the coolant’s radiolysis to mitigate the corrosion of structural materials.In the present work,a model to simulate aqueous ammonia radiolysis is established.The model was validated by comparing the calculation results to the experimental data,in which,the maximum relative error between the calculation result and the experimental data is less than 20%.The model was applied to study the effect of several factors（temperature,initial ammonia concentration,and dissolved oxygen） on ammoniacontaining coolant radiolysis.The consumption of ammonia slows down significantly when the temperature rises from 25℃ to300℃.The fraction of ammonia loss reaches 45% when the absorbed dose is 18 kGy at 25℃,whereas the corresponding absorbed dose is 8.6×10⁶ kGy in the same case when the temperature is 300℃.Differently,the concentration of H₂ displays a drop as the temperature increases.Growth of initial concentration enhances the radiolysis ratio of ammonia,however,the radiolysis ratio of ammonia decreases from 80.2% to 40.5% when initial ammonia concentration increases from 5 ppm to 50 ppm（at1.0×10⁷ kGy）.Besides,H₂ exhibits a positive linear dependence on ammonia loss.The presence of dissolved oxygen in the coolant promotes the radiolysis of ammonia solution but suppresses the concentration of H2.The proportion of ammonia loss is45.5% in the oxygen-free aqueous ammonia when the absorbed dose is 1.0 × 10⁷ kGy,whereas that value is 57.9% in the ammonia solution dissolving 8 ppm oxygen.Besides,H₂ exhibits a negative linear dependence on O₂ concentration.Therefore,it is necessary to remove the initially dissolved O₂ in the coolant.更多还原