Development of Phased Array Ultrasonic Inspection Techniques for Testing Welded Joints in Plastic (PE) Pipes

Polyethylene (PE) pipes have been used for gas and water pipework for decades, and have also been incorporated into some non-safety piping systems in nuclear power stations. Due to the material being immune to water corrosion and highly resistant to fouling, it is considered to replace coated carbon steel in safety-critical applications in nuclear power stations. However, the regulatory bodies require the welded joints to be inspected volumetrically and currently such a system is not available. Consequently, there is a need for a reliable NonDestructive Testing (NDT) approach for the inspection of different polyethylene (PE) pipe joints in various material grades and pipe sizes. In this paper the progress of developing the inspection techniques for two types of pipe joints and different sizes is presented. The joints require several different techniques to fully cover the weld fusion zones. Detection results from the pipe samples and initial evaluation of the capability of the inspection techniques are presented. Keyword: Phased array ultrasound, plastic pipe inspection, butt fusion, electrofusion