Film forming amine maintenance effect on steam generator feed water pipe of PWR nuclear power plant

Abstract Octadecylamine was investigated focusing on the inner wall of steam generator feed water pipe of PWR nuclear power plant. The maintenance process and adsorption mechanism of octadecylamine on A515-60 carbon steel were examined using material interface characterization methods. High-temperature and high-pressure de oxidation electrochemical test circuit was constructed to simulate the service environment of SG feed pipe inner wall carbon steel. Various analytical techniques including Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), Transmission Electron Microscopy (TEM), Electrochemical Impedance Spectroscopy (EIS), Partial Discharge (PD), contact angle measurements, and corrosion weight loss analysis were employed to characterize the surface morphology, elemental composition, maintenance effect, and corrosion rate of bare A515-60 carbon steel after film formation in octadecylamine solution. The study delved into the effects of film formation concentration, temperature, time, and dosing method on film formation efficacy. The following key conclusions were drawn: 1) Various concentrations of octadecylamine solution will create a hydrophobic film on the top of A515-60 carbon steel. When the concentration of octadecylamine was below 10mg/L, it might promote localized corrosion of carbon steel; however, when the concentration exceeded 20mg/L, it effectively inhibited carbon steel corrosion, with maintenance effects stabilizing after an 8-hour film formation period. 2) Under the condition of one-time dosing, a concentration of 20mg/L was recommended as optimal for application in the maintenance of carbon steel within the inner wall of SG feed pipes, with an 8-hour film formation period being the most effective. 3) Continuous dosing processes were identified as an essential area for further research.