Abstract: For passing stepwise bottles (F, F') in front of different stations, in order to more particularly take liquid samples, the bottles are placed in receptacles formed on a plate (24). The rotation of the plate is ensured by a lifting support action using compressed air delivered by injectors (18). Immediate rotation stoppage is obtained when a hole (38) formed in plate (24) faces the end of an optical fiber, whereof the opposite end issues onto an optical detector. Associated with an automatic sampling and dilution system, the assembly can be advantageously installed in a glove box or shielded enclosure in the nuclear industry.

Abstract: A hairpin spring for holding a fuel rod in a fuel assembly grid consists of a metal strip bent to form two mutually confronting legs arranged to be welded together locally. At least in a zone which bears on the other leg, one of the legs is U-shaped and straddles the other leg through a respective window of the grid. The legs of the U may be formed as appendices bent substantially at 90.degree.. The arms may also close up slightly so that the other leg can snap thereinto or flare for self-centering of the other arm.

Abstract: Package for shipping dangerous materials to ensure the containment of these materials under conditions of severe accident. A containment enclosure of austenitic stainless steel, constituted by a single part devoid of orifices and of joints other than welds, has the shape of a cylinder of revolution closed at its two ends which are of convex shape. The wall of this enclosure is of a substantially uniform thickness without sudden variations including the area of the welds. Two axial shock absorbers, each formed by a section of metal tube preferably of the same cross-section as the above enclosure, are positioned on the end of the latter so that they are coaxial therewith. A support ensures the storage and the handling of the assembly are provided, as well as if necessary, removable means adapted to ensure the wedging of the dangerous materials inside the enclosure.

Abstract: Fuel assembly for the core of a nuclear reactor comprising spacing grids situated in the upper part of the assembly arranged at smaller intervals from one another than the grids situated in the lower part of the assembly. The upper grids ensure a more intense mixing of the coolant downstream than the lower grids, so as to reduce corrosion at the upper part and the temperature difference between the top of the sheath and the coolant.

Abstract: The invention relates to an apparatus for the regeneration of active carbon comprising particularly:a hopper for introducing the active carbon;a reactor (7) delimited by an elongated shaped sheath;a continuous Archimedes screw (10) situated inside the reactor to transport the active carbon to be regenerated;structure for heating by resistances (8), arranged inside the sheath of the reactor;structure situated above the unload end of the reactor (19) and in communication with the reactor, particularly for removing the gases;a coffer into which the Arichmedes screw unloads;structure for communication with the reactor and situated on the one hand close to the input of the reactor and on the other hand along the reactor to regulate the pressure inside the reactor and to inject steam.This apparatus for regenerating active carbon enables the powder active carbon to be regenerated efficiently.

Abstract: During the dismantling of a nuclear reactor fuel assembly, there is a simultaneous gripping of all the rods (a) arranged in square grid form in said assembly using a device (10) which effects a clamping or locking at the end of the rows of rods. For this purpose, device (10) has passageways (26) penetrated by the ends of two adjacent rows of rods (a). In said passage ways are trapped mobile members (34, 34') arranged in such a way that each rod is placed between two adjacent members. By applying a locking force on the mobile end members in each passageway (26), each rod is gripped between two members (34, 34'). Preferably, the mobile members (34, 34') are provided with abutments limiting the locking or clamping force individually applied to each rod. For filling the gaps of the grid of rods (a) corresponding to the locations occupied by the guide tubes in the assemblies, rollers (78) are placed in the passageways (26) at the corresponding locations.

Abstract: In order to transfer a bundle of rods of or from a nuclear fuel assembly into a storage case, the bundle is placed in a waiting position above a cassette provided with recesses. The rods are then introduced into the recesses by lowering them by gravity. When the cassette is full, it is brought into the extension of the case by interposing a transformation member. By simultaneously exerting a thrust on all the rods, the latter are compactly transferred into the case.

Abstract: A nuclear fuel assembly comprising a plurality of fuel elements, a structure having an upper end piece and a lower end piece rigidly connected together by tie rods and a plurality of spacing grids. The plurality of spacing grids comprises two end grids, one being connected to the fuel elements and secured to the tie rods and the other being connected to the fuel elements and slidably received by the tie-rods, and a plurality of intermediate grids secured to the tie-rods and slidably received by the fuel elements. The bundle of fuel elements can extend and retract from the end grid which is secured to the tie rods while being maintained and supported by the structure.

Abstract: A machine for handling nuclear fuel assemblies includes a horizontally movable platform having a vertical telescopic mast whose lower part has a gripper for gripping the upper end piece of the assembly. The mast has several vertical rigid elements ending with segments which bear laterally each on a face of the lower part of the assembly to be inserted. The shoes are independently retractable. They index and center the assembly during reloading already irradiated assemblies. The machine may be used for reloading fuel assemblies into a nuclear reactor.

Abstract: A grid for use in a PWR assembly includes a peripheral girdle and at least two sets of parallel plates. The plates of one set are at an angle with respect to those of the other set so that the sets defined cells for the fuel rods. The parallel plates are distributed in at least two beds spaced apart in the longitudinal direction of the assembly. In a fuel assembly having a triangular array of fuel rods, three successive beds of mutually parallel plates are provided.

Abstract: For sampling a section of a tube in a nuclear fuel assembly comprising a skeleton formed by two end-pieces joined by tubes fixed to the end-pieces an opening for the extraction of the section through the upper end-piece is cut out with a milling cutter. Through the inside and by means of a cutting tool, the spacer tube is cut off at a level beneath the junction with the upper end-piece by means of a rotary tool introduced through the upper end-piece and the latter is extracted through the opening.

Abstract: The device for coupling two pipes comprises a variable length assembly formed from two tubular parts, whereof the internal diameter corresponds to the internal diameter of the pipes. The tight coupling of this assembly to the ends of the pipes is brought about by compressing O-rings between a planar surface and a spherical surface by means of two nuts. The two tubular parts are then tightly joined by actuating a nut compressing a third O-ring.

Abstract: A spacing grid for a nuclear fuel assembly, particularly a water cooled assembly, includes two spaced sets of plates. Each set is formed of plates parallel to each other and fixed at their ends to a polygonal belt in the form of a strip having fins along one longitudinal edge at least. Each corner of the belt is free of openings. Two at least of the corners are rounded and located inside of imaginary extensions of the flat lateral faces of the belt. They are connected to the edges of the lateral faces by gussets sloping radially inwardly.

Abstract: The invention relates to a process for decontaminating and adjusting the pH of uraniferous solutions to render them compatible with the natural environment into which they may be discharged. This process is characterized in that the solutions to be treated having a natural pH from about 2.5 to about 6.5 and containing from about 1 to about 100 mg/l of uranium, are supplemented with an aluminum salt, such as sodium aluminate, in a sufficient amount for the final pH to be from about 5.5 to about 8.5 and for there to be precipitation, coagulation and adsorption of about 90% of the uranium initially contained in the solution and for the uranium content remaining in the final solution obtained to be equal to or less than about 1.8 mg/l.

Abstract: In order to seal an opening formed in a vertical wall, a removable partition is formed, which is constituted by at least two dry-stacked brick layers. Each layer is formed from several rows of bricks, each constituted by bricks which, in cross-section, are shaped like a parallelogram, arranged in opposite directions on either side of a central locking brick which, in cross-section, is shaped like an isosceles trapezium. Each row of bricks behaves like a fictitious funicular arc when exposed to a horizontal force normal to the partition. Thus, the earthquake resistance is ensured without adding a reinforcing framework to the two faces of the partition.

Abstract: A glove box having an air admission device (6) and an air exhaust device. The air admission advice (6) includes a moving mechanism (60, 76) of which at least a portion is situated inside of the valve body (44), this moving mechanism acting on the one hand on a regulating valve (94) and, on the other hand, on a low-vacuum safety device (98) adapted for plugging an exhaust pipeline (54) opening into the valve body (44).

Abstract: The invention relates to an air-tight, shielded enclosure equipped for emission spectrometry. The air-tight enclosure (4) outside of which the high-frequency generator (1) and the spectrometer (3) are located, contains the inductor plasma source (2). The enclosure is provided with an insulating and biologically protective high-frequency lead-through (6), a Faraday cage (16), an air removing hood (17), and a baffle output (24) of the image of the plasma. This equipment makes it possible to apply emission spectrometry to the analysis of radioactive elements.

Abstract: The device is applicable to the connection of two enclosures, each having a door closing and opening formed in a flange. One of the doors supports a rotary control member having three series of slots forming cams. V-shaped levers articulated to the doors simultaneously cooperate with slots and with the bolts in order to displace the latter between locking and unlocking positions under the action of rotating the member. The configuration of the slots makes it possible to control the locking of the doors to one another and to the flanges in a sequential manner. Preferably, the bolts are inclined in the direction aiding sealing.

Abstract: A transfer device between a container and a confinement enclosure comprises a chamber having an opening issuing to the outside and an opening issuing into the enclosure. These openings are closed by doors constituting with an external door and an internal door of the container, to double door transfer systems. In order to permit the engagement of the chamber door on the inner door of the container following the removal of the first double door, the opening is formed on a mobile skirt connected by a sealing bellows to the enclosure wall.

Abstract: The invention relates to a process for recovering and purifying the molybdenum from a solution containing more molybdenum than vanadium.The process of the invention comprises the step of contacting the solution which contains molybdenum and vanadium, originally at a pH at least equal to 11 with an excess of an ammonium salt sufficient to precipitate the greatest part of vanadium in the form of solid ammonium vanadate, this excess being yet hot higher than a value such that after precipitation of vanadium, the quantity of ammonium having not reacted with the vanadate would be over a concentration which would account for risks of precipitating also molybdenum which is contained in the liquid phase of the supernatant.The molybdenum which is obtained is of industrial grade.