Flexible micro magnetic sensor array for nondestructive evaluation

A flexible micro magnetic sensor array has been developed for nondestructive evaluation in nuclear power plants, and its fundamental characteristics are investigated. The flexible micro eddy current testing (ECT) probe consists of a pancake-shaped exciting coil and a flexible micro magnetic sensor array. The array has sixteen micro coils made of copper formed on a flexible polyimide film by photolithography. Each coil has 40 turns within the area of 2×2 mm². The flexible sensor array can be applied to the micro ECT probe of any geometric configuration. The detection and reconstruction of flaws in the conductive tubing of the steam generator of a pressurized nuclear power reactor by using the flexible micro ECT probe are considered. The flaws are caused by mechanical stress and fatigue, chemical corrosion or radiation damage