在不同碱化剂溶液中TU48C钢的均匀腐蚀及流动加速腐蚀速率

Uniform Corrosion and Flow Accelerated Corrosion Rates of TU48C Steel in Different Alkalizer Solutions

利用高温高压釜及自主研发的模拟核电二回路环境材料评估试验平台,研究了压水堆核电厂二回路用TU48C钢在氨(NH_3)、乙醇胺(ETA)碱化剂溶液中的均匀腐蚀速率以及在NH_3、ETA、质量比为1∶1的ETA+NH_3等3种碱化剂溶液中的流动加速腐蚀(FAC)速率。结果表明:在150℃下,TU48C钢在ETA和NH_3溶液中的均匀腐蚀速率相近,均随腐蚀时间的延长而降低;在给水pH(25℃)为9.7条件下,以NH_3作为碱化剂时,TU48C钢的FAC速率最大,以ETA为碱化剂时的最小,以ETA+NH_3为碱化剂的介于上述两者之间,且接近以ETA为碱化剂时的值;采用ETA或ETA+NH_3代替NH_3作碱化剂可以大幅度降低核电厂二回路汽水分离再热器疏水管的FAC速率。

Using the high-temperature autoclave and independently developed material evaluation test platform that can simulate the second circuit environment of the nuclear power plant,the uniform corrosion rates in NH3 and ethanolamine（ETA）alkalizer solutions and the flow accelerated corrosion rates in NH3,ETA,and in 1∶1 mass ratio of ETA and NH3 alkalizer solutions of TU48C steel,which was used for the second circuit of the pressurized water reactor of nuclear power plant,were researched,respectively.The results show that at 150 ℃,the uniform corrosion rate of TU48 Csteel in ETA solution was similar to that in NH3 solution,and both decreased with the increase of soaking time.When the pH（25 ℃）value of feeding water was 9.7,the FAC rate of TU48C steel was the highest with NH3 as alkalizer while the lowest with ETA as alkalizer.The FAC rate with ETA and NH3 as alkalizer was between those with the above two alkalizers,which was close to that with ETA as alkalizer.Substituting ETA or ETA＋NH3 for NH3 can significantly reduce the FAC rate of the hydrophobic pipe of the moisture separator reheater in the second circuit of nuclear power plant.