Method and device for measuring the diameter of a peripheral pencil of a nuclear reactor fuel assembly

摘要

The diameter of a segment of a peripheral rod (2) in a fuel assembly is measured between two successive spacer grids (3). A measuring tool (14) is positioned at a level situated between the two successive spacer grids (3), the tool comprising two measuring fingers (18) that are free to move relative to each other in a first horizontal direction (X) and that are urged towards each other by resilient return means, and that extend in a second horizontal direction (Y) perpendicular to the first horizontal direction (X). The measuring fingers (18) are moved in the second horizontal direction (Y) towards a rod (2) so as to put two contact pieces of the measuring fingers (18) into contact with two zones of the rod segment. The measuring fingers (18) are moved in the vertical axial direction of the rod along its segment situated between the two spacer grids (3) and an electromagnetic sensor is used to measure the distance between the measuring fingers (18) in the first horizontal direction while the measuring fingers (18) are being moved axially.