Thin layer activation for probing flow accelerated corrosion of carbon steel

Carbon steel feeder elbows and feeder piping of the primary coolant system of pressurized heavy water reactors undergo significant wall thinning due to flow accelerated corrosion. The rate of corrosion in certain locations exceeds the design corrosion allowance. Corrosion rate is dependent on several parameters like pH, temperature, dissolved oxygen, chromium content in material, pipe geometry, etc. Thin layer activation, utilizing the 57Fe(p,n)57Co reaction, enabled rapid online measurement of wall thinning in a simulated straight feeder pipe. Significant velocity and pH dependence was observed for corrosion rates and the same were compared with the predictions by Sanchez-Caldera model.

► Corrosion rate in certain locations of feeder piping exceeds the design allowance.
► Online measurement of localized wall thinning in a short time.
► Velocity and pH dependence of corrosion rates predicted by Sanchez-Caldera model.
► Surface roughness corrections mandatory for extrapolation of experimental results.