Abstract: The present invention relates to a method for refurbishing an atomic fuel assembly storage rack the partitions (10) of which include a layer (14) of neutron-absorbing material between a wall (16) and a more or less rectangular piece of sheet metal (18) welded onto said wall. In this method the sheet metal is cut along each of the four sides. Once the short sides of sheet metal (18) have been cut by cutting the welding spots or by cutting it into sections the long sides are cut using a cutting head (20) that includes one to four blade-blade support assemblies (22) or one to four blades. Each blade (24) and blade support (26) is either fixed or movable.

Abstract: A nuclear fuel rod assembly storage rack comprises a rigid structure delimiting vacant spaces of square, cross-section and neutron-absorbing units also having a square cross-section prearranged before introduction into all or part of the vacant spaces between the shroud tubes. Each neutron-absorbing unit is made up of four flat plates of neutron-absorbing material, surrounded by at least two support grids. The support grids may comprise two units assembled together, for example by welding.

Abstract: A storage rack for nuclear fuel assemblies and its manufacturing process.A storage rack for nuclear fuel assemblies is formed by assembling main plates (12), spacer plates (14), two end plates (16) and a base plate (18), preferably by welding. Once a first main plate (12(1)), a first end plate (16(1)) and the base plate (18) have been mounted on a tooling, a first series of housings (10) is formed by securing a first row of spacer plates (14(1)) to the first main plate (12(1)), and then mounting a second main plate (12(2)). The other rows of housings (10) are obtained in the same manner. The rack is completed by mounting the second end plate.

Abstract: Process for the renovation of a nuclear fuel assembly storage rack.For the renovation of a nuclear fuel assembly storage rack, whereof the bulkheads (10) incorporate a neutrophage material sheet held between the partition (16) and a plate (18) welded to said partition, the plate (18) is cut, the sheet extracted and is replaced by a new neutrophage material sheet. This process obviates the need for replacing the rack when the sheets have dissolved in the water of the pool containing the rack.

Abstract: A sealing device comprising a supporting assembly (9) containing sealing members (16) supporting the instrument column (5), and an assembly (17, 18) for lifting the instrument column (5) in sealing engagement with the supporting members (16). The sealing members (16) supporting the instrument column (5) include a clamping ring (28) and at least one O-ring seal (29, 30). Axial movement of the instrument column (5) enables clamping of the inner seal (30) via the clamping ring (28). When axial movement of the instrument column (5) is restricted, the seals may be clamped by means of a suitably sized clamping ring (28).

Abstract: System, device and process for inspection of a thermal neutron absorption wall. The device comprises a fast neutron source and an arrangement for thermal neutron detection comprising at least one pair of oblong, substantially parallel thermal neutron detectors placed side by side, and substantially perpendicular to the direction of displacement of the device along the neutron absorption wall.

Abstract: The instrumentation column (5) comes to bear via a bearing surface and a sealing gasket (16) inside a bearing element including a tubular length (8) and a closure cover (11) joined together by screwed assembly means. The tubular length (8) and the cover (11) each include a bearing surface (33a, 34) which is symmetrical of revolution about the axis of the instrumentation column (5). The bearing surface (33a) of the cover (11) and the bearing surface (34) of the tubular length (8) between them, through direct metal-to-metal contact, provide sealing against the pressurized water of the reactor.

Abstract: An installation, designed to stock both nuclear fuel assemblies of square section and control bars of cruciform shape taken from a boiling water nuclear reactor, comprises vertical housings of square section, each able to accommodate a control bar and four assemblies. The housings are formed in and between encasing tubes (22) which rest upon a lower plate (10). After placing a control bar in the housing, a removable unit (30) is inserted which comprises a baseplate (34) surrounding the tip of the bar, four holders (32) resting on this baseplate, and spacer wedges (36) separating the holders. One assembly is then placed in each holder (32).

Abstract: The detection device includes at least one thermocouple (10) arranged aligned with the bottom head of the vessel of the nuclear reactor, having a first branch (9) made of a first metallic material and at least one second branch (11) made of a second metallic material, different from the first material, welded to a point on the first branch constituting a hot junction of the thermocouple (10). The first branch (9) of the thermocouple has the form of an elongate hollow section. The device furthermore includes means for analyzing the measurements taken by the thermocouples (10).

Abstract: A device for treating cerebral lesions by gamma radiation, comprising an approximately semi-spherical source-collimator assembly having a large number of gamma ray sources associated with channels directed to the same focal point. Each gamma ray source is associated with a group of channels arranged in the manner of a cone, the apex of which is at the focal point.