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

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 TU48C steel 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.