添加Zn^2+对ZIRLO合金在模拟压水堆一回路含LiOH和H3BO3水溶液工况下耐腐蚀性能的影响

对ZIRLO合金在360℃,18.6 MPa,含LiOH和H3BO3溶液的高温高压釜中进行了水侧腐蚀实验;并通过在其中的一个高压釜中加入乙酸锌,从而对比研究了加Zn对ZIRLO合金耐腐蚀性能的影响。结果表明:在腐蚀介质溶液中添加50μg/kg乙酸锌对ZIRLO合金的腐蚀增重情况、氧化膜厚度、氧化膜中第二相种类及大小、氧化膜表层元素的种类、分布及价态并无显著影响,但降低了氧化膜表层沉积物中Fe的含量,并抑制了国产新锆合金腐蚀过程中的吸氢。

Effect of Zn(CH3COO)2 Addition on Corrosion of ZIRLO Alloy in Simulated PWR Primary Loop Medium with LiOH and H3BO3

Zn(CH3COO)2 injection in PWR primary loop can slow down the corrosion of structural materials.During the running time of PWR,the water-side corrosion of Zr-based alloy,as fuel element cladding material,may result in significant hydrogen uptake,embrittlement and cracking etc.of the Zr-based alloy,and finally the invalidation of cladding material.In this study,the corrosion behavior of ZIRLO alloy was assessed in LiOH and H3BO3 containing aqueous solution at 360℃/18.6 MPa with addition of 50μg/kg Zn(CH3COO)2 via an autoclave test set,as well as weight change measurement,metalloscopy,XPS and TEM with EDS.The results show that the Zn(CH3COO)2 addition has no significant effect on the weight gain and scale thickness,while the type,valence state and distribution of elements in the formed oxide scale of the tested ZIRLO alloy,but can remarkably reduce the Fe content of the deposits on top of the formed oxide scale,and correspondingly restrain the hydrogen absorption of the ZIRLO alloy.