Pipe-Thickness Measurement Technology Using EMAT and Fiber Optic Sensors

In the piping system in power plants, the pipe elbows and lower reaches of orifices are prone to damage from flow-accelerated corrosion and erosion. Conventionally, an ultrasonic meter is used to measure the thickness of the main pipes and detect corrosion loss. However, this involves the time and cost of shutting down the plant to dismantle and reassemble the heat-insulating jackets of the pipes. Therefore, we developed a new measurement technology that combines the use of electromagnetic acoustic transducers (EMATs) and fiber optic sensors. The sensor device can be placed between the pipe and the heat insulator, allowing online measurement and monitoring of pipe thickness. This report describes the detection of liquid droplet impingement (LDI) erosion on the inner surface of pipes using the EMAT and fiber optic sensor method.