配管分岐合流部における流れ加速型腐食の減肉特性

抄録

Flow Accelerated Corrosion (FAC) is a pipe wall thinning phenomena to be monitored and managed in the power plants with high priority. Its management has been conducted with conservative evaluation of the thinning rate and the residual lifetime of the piping based on the wall thickness measurements. However, noticeable case of the wall thinning was occurred in the tee tube. It is a problem to manage the section beneath the reinforcing plate of the tee tube; the region where measurement is difficult to conduct with ordinary ultrasonic testing device. In this study, numerical analysis for the tee tube was conducted, and the wall thinning profile due to the FAC was evaluated by calculating the mass transfer coefficient. In the case of the union flow, the wall thinning profile showed the tendency of increase at the junction in association with decreasing of branch pipe’s diameter.