A new ultrasonic inspection system for non-destructive examination of precision tubes

A system based upon a rotating water chamber with eight ultrasonic transducers is described which has been designed for the fast, stringent and automatic inspection of the dimensions of, and defects in, precision tubes such as those used for fuel encapsulation in water-cooled nuclear reactors. The principles incorporated in the system are summarized as follows; both dimension and defect measurements are made using the same system, an ultrasonic pulse-echo technique is used which requires no contacts, measurements of inner diameters are made from the outside of the tube, the spiral scan used is achieved by rotating the transducers instead of rotating the tubes, and results are registered and evaluated by computer. Evaluation and development work on the system that has been carried out, based on practical tube inspection experience, is described. (U.K.)