Abstract
Many industrial infrastructures was built more than 40 years ago, needs are increasing that pipe corrosion should inspect reasonably. There are many piping inspection technology for piping installed on the ground and high altitude, but for piping installed in underground are in the minority. We focused on the ultrasonic guided waves technology, start development of the high-powered guided waves technology corresponding to the strong attenuation in underground. We introduce the results of verification tests for underground piping using the inspection equipment we developed.