Realization of ultrasonic images of immersed metallic structures using a digital beamforming system. Experimental study

The CEA and EDF (French electricity utility) have identified fast ultrasound imaging in sodium as an important part of the research and development program concerning in-service inspection of Fast Breeder Reactors (FBR). In order to improve existing inspection systems, it was decided to design an ultrasound imaging system capable of taking into account the additional information provided by the backscattering due to rough metallic surfaces. This system, based on an orthogonal imaging concept, is comprised of two linear arrays of 128 elements laid out orthogonality and operating at a centre frequency of 1.6 MHz. Ultrasound images of metallic structures similar to those found in FBRs were produced using an experimental configuration immersed in water.