Method of inspecting the welding of a sealed closure plug of a nuclear reactor fuel element

A method of inspecting welding of a sealed closure plug of a fuel element for a nuclear reactor, the fuel element having a tubular sleeve enclosing a plurality of nuclear fuel pellets stacked in an axial direction of the sleeve and two sealed closure plugs having a cylindrical part inserted coaxially into an axial end part of the sleeve, the plug welded in a welding station by melting the sleeve and the plug along a circular line in a joint plane perpendicular to the axial direction of the sleeve and the plug through welding directed radially relative to the circular line in the joint plane of the sleeve and the plug, which are coupled to a rotation arrangement for rotation about a common axis, inspection effected by processing digitized optical images of areas of the fuel element adjoining the circular line and distributed along a periphery of the fuel element, the method comprising:

• rotating the sleeve and the plug about the common axis with aid of the rotation arrangement before welding the plug and the sleeve, the plug and the sleeve configured in a welding position at the welding station, wherein images are taken along the periphery of the fuel element to obtain the digitized optical images which are analyzed to determine a position of the joint plane, and a rotation of the fuel element is verified;
• deducing at least one of to perform the welding or not to perform the welding;
• and
• taking images, if the welding is performed after welding the plug to the sleeve of the fuel element of the fuel in the position at the welding station, along a circumference of the external surface of the fuel element in a vicinity of the line to obtain the digitized optical images, the digitized optical images analyzed to check a conformance of as weld a long the line.