某核电厂循环水管牺牲阳极工艺保护电位异常分析  

Analysis on the Abnormal Protection Potential of Sacrificial Anode Process for Circulating Water Pipeline in a Nuclear Power Plant

作　　者：张瑞祥[1] 姚尧 余俨 孙文钊 左创举 武方杰 ZHANG Rui-xiang;YAO Yao;YU Yan;SUN Wen-zhao;ZUO Chuang-ju;WU Fang-jie(Xi’an Thermal Power Research Institute Co.,Ltd.,Xi’an 710000,China)

机构地区：[1]西安热工研究院有限公司,陕西西安710000

出　　处：《材料保护》2021年第12期187-190,共4页Materials Protection

基　　金：华能集团总部科技项目“NHKJ20-H15核电站建设全周期设备防腐及保养技术研究”资助。

摘　　要：某核电厂循环水管道外表面防腐蚀采用双层环氧煤沥青涂层和镁合金牺牲阳极工艺,从2018年起开始对牺牲阳极4个测试桩进行定期检测,发现牺牲阳极保护电位在-0.70 V左右,保护电位发现异常现象,说明循环水管道处于欠保护状态,循环水管道有潜在的腐蚀风险。为此,在核电厂现场开挖了1个循环水管的镁合金阳极块,从管道特性阳极系统的设计核算,镁合金阳极块的化学成分和电化学性能等方面进行了测试分析。结果表明:阳极设计符合标准要求,镁阳极块的化学成分和电化学性能均不合格。最后分析了保护电位异常的可能原因,提出了相应的建议。The double-layer epoxy coal tar pitch coating and magnesium alloy sacrificial anode process are used for the corrosion protection of the external surface of the circulating water pipeline in a nuclear power plant.When four test piles of the sacrificial anode were inspected regularly since 2018,it was found that the protective potential of the sacrificial anode was about-0.70 V,abnormal phenomena found in protection potential,which indicated that the circulating water pipeline was under-protection and the circulating water pipeline had potential corrosion risk.Therefore,the magnesium alloy anode blocks of 10 circulating water pipes were excavated at the site of nuclear power plant.The pipeline characteristics,design and accounting of anode system,chemical composition and electrochemical properties of magnesium alloy anode block were tested and analyzed.Results showed that the anode design met the standard requirements,however,the chemical composition and electrochemical properties of magnesium anode block were unqualified.Finally,the possible causes of the abnormal protective potential were analyzed and the corresponding suggestions were put forward.

关 键 词：核电厂 循环水管道 镁阳极 特殊阳极 外加电流法 

分 类 号：TG172[金属学及工艺—金属表面处理]