General Electric Company

Kurt D Ellis

David Grey Smith

Harold B King

Michael Kent Cueman

Frederick C Schoenig, Jr

James D Landry

John A Kervinen

David K Underwood

A combined ultrasonic and eddy-current method and apparatus for non-destructively determining the liner thickness of a zirconium liner provided at the inner surface of a zirconium alloy nuclear fuel rod tube utilizes dimensional data acquired via conventional ultrasonic measurement techniques and impedance data acquired through electromagnetic techniques to calculate liner thickness in accordance with a specific formula. The apparatus utilizes a computer or programmable arithmetic unit with associated memory and I/O devices connected to electromagnetic and ultrasonic measurement subsystems. A particular eddy-current probe arrangement consisting of a differential coil pair is employed to obtain impedance measurements from the outside of the cladding tube. Calibrated reference impedance values for various different inner and outer tube diameters having a constant liner thickness are measured and retained in a memory. Calibrated reference impedance values for tubes of various liner thicknesses with the same inside and outside diameter dimensions are also measured and stored. A specimen cladding tube is tested and an inside diameter is computed using conventional electromagnetic techniques. The specimen tube inside diameter is also measured ultrasonically and a specific calculation of liner thickness is performed based on the difference between the inside diameter as determined by ultrasonic technique and the inside diameter as measured by eddy-current technique. The specific method of calculation utilized corrects for the erroneous effect that variations in cladding tube liner thickness can have on dimensions computed via conventional electromagnetic eddy-current techniques alone.

Combined ultrasonic and eddy-current method and apparatus for

A method and apparatus measure squareness of an end of a rod relative to a longitudinal centerline axis thereof without requiring rotation of the rod. The apparatus includes a flat plate mounted substantially perpendicularly to the rod centerline axis. The method positions the plate in abutting contact with the rod end, and a tilt angle of the plate in abutting contact with the rod end is measured for determining squareness of the rod end.

Method and apparatus for measuring rod end squareness

A method for operating a computer to control the manufacture process of zirconium tubes in a pilger mill operation, the computer including an electronic memory and being coupled to the pilger mill to receive, as input, data related to the operation of the mill. The method comprising, in one embodiment, the steps of storing in the computer memory respective test signals, each test signal corresponding to a signal obtained by inspecting a tube manufactured by the mill with a respective, known defective operation condition, inspecting a zirconium tube finished by the manufacture process and generating a signal representative of the physical dimensions and material configuration of the tube, comparing the generated representative signal of the zirconium tube with the stored test signals, alerting an operator if the generated representative signal of the zirconium tube correlates to a stored test signal, and identifying the defective operation condition which corresponds to the correlated stored test signal.

Method for controlling the manufacture of zirconium tubes

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Wilmington, NC, United States of America

Kurt D Ellis