Abstract: A method of repairing a heat exchanger tube in a steam generator includes the step of removing a degraded tube segment from an operative heat exchanger tube in a steam generator. A weld metal ring is then positioned between the operative heat exchanger tube and a new tube segment. The weld metal ring is then welded to the operative heat exchanger tube and the new tube segment to form a linking tube section. The linking tube section is then heat treated. The new tube segment is then expanded toward a steam generator tubesheet. Finally, the new tube segment is welded to the tube sheet.

Abstract: Guided ultrasonic waves are used for the detection of defective tubes in a heat exchanger or steam generator by using a transducer which generates a guided wave at predetermined parameters of phase velocity and frequency to operate at a point on a dispersion curve which minimizes leakage of ultrasonic energy to fluid surrounding the tube. Various techniques of generating ultrasonic waves of various phase velocities such as a comb type filter allow phase velocity points on a dispersion curve to be freely selected.