Eddy current testing of heat transfer tubes in industrial cooling water heat exchangers of a power plant

When conducting eddy current testing on the heat transfer tubes of an industrial cooling water heat exchanger in a power plant, it was found that multiple heat transfer tubes had external wall defects, all located at the limit rods. After pipe pulling, it was verified that they were all wear defects of the limit rods. Due to the special structure of the equipment, there was a point contact between the limit rods and the heat transfer tubes. Based on the characteristics of the eddy current signals generated, the authors conducted a comparative study on the analysis and quantitative methods of these defects and provided practical experience for eddy current testing of similar equipment.