泡核沸腾对高温富氧水中Zr合金腐蚀行为的影响  

Effect of Nucleate Boiling on Corrosion Behavior of Zirconium Alloy in Oxygen-enriched High Temperature Water

作　　者：曾奇锋 刘妍洁[3] 张乐福 司胜义[4] 李聪 卢俊强[2] 刘庆冬[3] ZENG Qifeng;LIU Yanjie;ZHANG Lefu;SI Shengyi;LI Cong;LU Junqiang;LIU Qingdong(Institute of Nuclear Science and Engineering,Shanghai Jiao Tong University,Shanghai 200240;Shanghai Nuclear Engineering Research&Design Institute Co.,Ltd.,Shanghai 200233;School of Materials Science and Engineering,Shanghai Jiao Tong University,Shanghai 200240;Nuclear Power Operations Research Institute,Shanghai 200120)

机构地区：[1]上海交通大学核科学与工程学院,上海200240 [2]上海核工程研究设计院股份有限公司,上海200233 [3]上海交通大学材料科学与工程学院,上海200240 [4]核电运行研究(上海)有限公司,上海200120

出　　处：《机械工程学报》2024年第24期199-210,共12页Journal of Mechanical Engineering

基　　金：企业能力建设课题资助项目(20YW016)。

摘　　要：为了揭示空泡份额对高温富氧水中Zr合金表面水垢沉积和腐蚀行为的影响规律,采用高温高压动水回路试验,对Zr-4和SZA-4合金包壳管开展42 d腐蚀行为的对比评价研究。通过扫描电镜(SEM)和透射电镜(TEM)对Zr合金氧化膜及水垢的显微组织进行了观察,采用氢含量分析仪对吸氢量进行测定。结果表明,随着沿包壳管轴向温度和空泡份额的提高,两种Zr合金氧化膜厚度均表现出增加趋势,氧化膜/基体(O/M)界面的起伏程度加剧,同时吸氢量随之增加。腐蚀42 d时,两种Zr合金均处于腐蚀转折前的早期阶段,氧化膜保持良好的致密性及保护性,外层为等轴晶区,内层为柱状晶区,分布着较多尚未被完全氧化的第二相析出粒子(SPPs),同时O/M界面存在明显的过渡层。包壳管表面水垢主要由不同晶粒尺寸的Fe的氧化物组成,可分为“疏松区”和“致密区”,其中疏松区的晶粒细小,存在大量孔洞。含Nb的SZA-4合金的氧化膜厚度大于无Nb的Zr-4合金,高温富氧水中的耐腐蚀性能较差,证实了Nb元素增加富氧环境中Zr合金腐蚀速率的事实,而这与常规压水堆环境中的腐蚀规律相反。In order to understand the effect of void fraction on CRUD deposition and corrosion behavior of zirconium alloy in high temperature water with dissolved oxygen,a 42-days corrosion test was carried out on Zr-4 and SZA-4 alloy cladding tubes in high temperature and high pressure water loop system.The microstructures of oxide and CRUD were analyzed by scanning electron microscope(SEM)and transmission electron microscope(TEM).The hydrogen absorbed by Zr metal substrate was examined by a hydrogen analyzer.The results show that,with the increase of temperature and void fraction along the cladding tube,the oxide film thickness of the two Zr alloys generally grow,the oxide-metal interface become uneven and hydrogen absorption increase accordingly.After corrosion for 42 days,both Zr-4 and SZA-4 alloys are still in the early corrosion stage before transition.The oxide consists of outer equiaxed grains and inner columnar grains,which is dense and totally protectable.There are several second phase particles(SPPs)without full oxidization distributing across the whole oxide,and a transition layer was observed at the oxide andα-Zr matrix(O/M)interface.The CRUD is mainly composed of iron oxide crystals with different grain sizes,and can be divided into loose and dense region,and there are a lot of holes in the loose region with small grain size.The oxide thickness for Nb-containing SZA-4 alloy is greater than that of Zr-4 alloy without Nb,indicating the inferior corrosion resistance of SZA-4 alloy in oxygen-enriched high temperature water.The phenomena confirm that Nb element increases the corrosion rate of Zr alloy when some dissolved oxygen is present in water,which is contrary to the corrosion behavior in conventional pressurized water reactor environment.

关 键 词：ZR合金 腐蚀 氧化膜 溶解氧 空泡份额 水垢 

分 类 号：TL341[核科学技术—核技术及应用]