Ultrasonic Inspection & Data Analysis for Failed Fuel Assembly

To safely, effectively, and accurately locate failed fuel assemblies in nuclear power plants through ultrasonic inspection methods, this study utilizes the characteristic that the medium state of the inner wall of the fuel cladding before and after damage will cause differences in the attenuation of circumferential Lamb wave energy in the cladding. The propagation path of the Lamb wave in the fuel cladding during the movement of the ultrasonic probe in the gap between fuel assemblies is analyzed theoretically, and the propagation sound path is analyzed and calculated. The deviation between the calculated results and the measured values is within ±2%. Based on the principle of ultrasonic detection and the characteristics of sound beam propagation, the automatic identification algorithm and data analysis software of fuel rod cladding echo signal are developed, which can realize the rapid analysis and screening of detection data. The test results of simulated fuel assemblies and field application verify that the detection method is fast, safe and effective in detecting the damaged location of leaking rods in fuel assemblies, and the automatic signal identification algorithm and data analysis software are accurate and reliable, which can provide a basis for the targeted repair of damaged fuel assemblies in the future and improve the utilization rate of nuclear fuel.