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

Abstract: 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.

Abstract: A measuring tool (10) comprising two jaws (15b, 15c) which can be moved one with respect to the other in a first horizontal direction and moved back towards each other by an elastic means, is set up level with the spacer-grid (3) of the fuel assembly. The measuring tool (10) is displaced in a second horizontal direction perpendicular to the first horizontal direction and to a front face (6a) of the spacer-grid (3) such that the jaws (15b, 15c) each come into contact with a lateral face (6b, 6c) of the spacer-grid (3) and the distance between the jaws (15b, 15c) is measured in the first horizontal direction. The tool (10) is mounted so as to rotate freely about an axis parallel to the vertical longitudinal direction of the fuel assembly (1) such that the measuring tool (10) is oriented freely with respect to the front face (6a) of the spacer-grid (3), when the measuring tool is displaced in the second horizontal direction.