Study on In-Service Inspection of Nuclear Fuel Assembly Failure Using Ultrasonic Plate Wave

Abstract

As protection for nuclear power plants is quite necessary, the nuclear fuel is sealed in zirconium alloy thin wall cladding. During in service, fuel rods might be damaged, such as wall-thickness thinning, cladding corrosion and cracking, etc. However, current diagnostic methods have limitations due to special structure of fuel assembly, underwater and radioactive environment. In this paper, a novel inspection method is proposed to recognize the failure of fuel rod by using the ultrasonic plate wave. The inspection model and process algorithm are proposed for in-service inspection. The relationship between signal and scanning position is established and analyzed. Both ultrasound field simulation and experiment have been carried out for validation. The corresponding results illustrate that the failed nuclear fuel rod of the whole fuel assembly (including the internal rods) can be effectively detected without influence of near-field region by using the proposed method.

Keywords: Ultrasonic plate wave, Nuclear failed rod, In-Service Inspection