System and procedure for inspection of the surface of a nuclear fuel rod for the automatic detection, location and characterization of defects

A system for inspection of a surface of a nuclear fuel rod for automatic detection, location and characterization of surface defects, the rod having a longitudinal axis, the system comprising:

• a plurality of point cloud acquisition systems, for obtaining a plurality of profiles, along a Y-axis which coincides with the longitudinal axis of the rod, the profiles defining a point cloud, each acquisition system being composed of:
• a linear laser beam,
• an optical sensor,
• and a point cloud acquisition card;
• wherein the number of acquisition systems, No. Adq.Syst., is given by the relationship:
• No. Adq.Syst.=f(Ørod)=└3+0.1Ørod┐,
• wherein └. . . ┐ denotes rounding to the nearest integer;
• wherein Ørod is the diameter of the nuclear fuel rod to be inspected;
• translation means for the nuclear fuel rod;
• wherein the system also comprises a processor capable of:
• transforming the point cloud into a height map representing a Z coordinate along a Z-axis perpendicular to a Y axis,
• carrying out a local thresholding for a segmentation of the height map, and obtaining a plurality of discontinuities in said map;
• classifying the plurality of discontinuities in different geometric shapes to obtain defects, wherein obtaining the defects comprises obtaining area, length, width, position and orientation of the defects,
• projecting the defects on the Y-axis to obtain a depth of the defects,
• calculating, starting from the projection of the defects on the Y-axis, -an equivalent function and a second derivative thereof to obtain points where the depth of the defect is maximized.