Abstract: A procedure for transferring an object along an axis, from a contaminated and radioactive zone to a clean zone without breaking the confinement when the zones are separated by a slab is disclosed. The slab contains a plug and the object can be secured to the plug with the use of a stationary pre-enclosure (43) equipped with two plugs (44 and 46) and of a movable transfer enclosure (47) equipped with one plug (48). The enclosure and pre-enclosure are placed in alignment with the transfer axis.

Abstract: A grid for supporting and spacing nuclear fuel rods, particularly at the nodes of a triangular array, has a peripheral frame of regular polygonal, typically hexagonal, shape and at least two beds of wires spaced in the longitudinal direction of the fuel assembly. Each bed has at least two series of mutually parallel wires secured to said frame at the end thereof, the wires of a same one of said series being parallel to two opposed side of said frame and all said wires defining passages for said fuel elements.

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: A manufacturing installation having several fixed work stations and a handling device, said work stations being disposed along at least one handling bay. It further comprises a handling device having, on the one hand, an overhead transporter movable along the handling bay and having means for grasping, transporting and setting down a batch of a given number of objects and, on the other hand, at right angles to each work station, an intermediate take up and storage device having an upstream station for setting down by the transporter, a downstream station for taking up by the transporter and a conveyor capable of grasping the batch of objects as a whole at the upstream station, presenting the objects one by one at the work station and placing them as a whole in the downstream station, so as to completely decouple the operation of the transporter from each work station.

Abstract: A sipping test for detecting defective sheaths in a nuclear fuel assembly is carried out by increasing the pressure of the gases within the sheaths by increasing the temperature. The fission products are released in case of sheath failure. A mixture of water and inert gas is introduced into a hood containing the fuel assembly. Gas and water are separated at the upper portion of the hood and are circulated in distinct loops for continuous detection of the water-soluble fission products and the gas-driven fission products.

Abstract: This invention relates to a centrifugal decanter comprising a rotor connected to a motor for driving in rotation by a vertical shaft suspended in pendulous manner by a swivel joint supported by a fixed connected seat. Springs for returning the shaft into vertical position are provided, in the form of compression springs arranged so as to relieve the swivel joint of the weight of the rotating system that it supports.

Abstract: A device is provided for transferring nuclear fuel element sheaths to a fixed pellet filling station. This device comprises a sheath transfer assembly. This latter comprises a first transporter for taking as a whole a layer of several sheaths placed on the laying rack of the first means associated with the first transporter and intended for changing the spacing pitch of the sheaths in the layer and for presenting the layer at the position for simultaneous filling of several sheaths by the vibrating table machine (50) for inserting fuel pellets, second pitch change means for bringing the sheaths back to the original pitch, a transporter cooperating with a second pitch change means for bringing the layer of sheaths as a whole onto a take up rack and means for the automatic synchronized control of the components of the assembly ensuring the movements of the sheaths always in the same direction.

Abstract: The apparatus is for welding grids, particularly for a nuclear fuel assembly, constituted by two sets of strips at right angles and whose terminal portions are made fast to a belt. It comprises, in an enclosure with a controlled atmosphere provided with a lock, a double cross movement table bearing at least one orientation device and which is capable of bringing each surface and each side of the grid in its turn into an orientation perpendicular to the firing line of a radiation welding member and to move the frame in two directions perpendicular to the firing line, so as to bring each spot to be welded in its turn opposite the firing line. The orientation device and the table are provided with control motors and constitute an automation for presenting all the weld spots to be formed successively opposite the firing line.

Abstract: A nuclear reactor has a stationary horizontal core plate and a plurality of upright nuclear fuel assemblies all having the same cross-section and located side by side in a regular polygonal network. Each fuel assembly either has two locations for elongated plug elements or is adjacent a fuel assembly having such locations. A device for holding down the fuel assemblies comprises a plurality of locking sets each having at least one deformable locking member and a rigid member one of which is carried by a fuel assembly and the other by the core plate. The deformable locking member is so located with respect to a location and with the associated rigid member that insertion of an elongated element into the location forces the deformable locking member into positive engagement with the associated rigid member.

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 apparatus is for dismounting nuclear fuel assemblies comprising a skeleton having an upper end piece, a lower end piece, guide tubes connecting the end pieces and fuel rods maintained by grids between the end pieces. The apparatus comprises a cell displaceable vertically in a water tank and provided, at its upper part, with a base plate having an opening for passage of one said fuel assembly and provided with means for gripping an upper part of the bundle of fuel rods. A centering unit is operable by a handling tool and is arranged for gripping the upper end piece of a fuel assembly. The guide tubes may be disconnected from the upper end piece while the bundle of fuel rods is retained in the cell.

Abstract: Device for inserting hair pin springs with two legs astride a plate having windows for locally welding the legs against one another. It comprises movable modules which receive one plate at a time in the vertical position and move it in the lengthwise direction for bringing it into successive positions each corresponding to the arrival of one of the spring reception zones in an insertion position where centering means temporarily hold the plate in said successive positions. A vibrating rail guides the springs to a take up position where a gripper takes each spring in turn by the end of one of its legs, then moves in a plane perpendicular to the plate along a path for introducing the other leg of the spring in the plate.

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: The device of the invention allows a hair-pin spring with two legs to be inserted astride a plate having windows for locally welding the legs together. This device receives one plate at a time and moves it lengthwise, and a corridor guides each spring in turn, the spring being moved along the corridor towards its insertion position. A mask movable parallel to the plane of the plate from the edge furthest from the zone through which the introduction takes place allows the window to be covered furthest from the zone through which the introduction takes place so as to avoid jamming.

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 assembly comprises fuel elements carried and retained by a structure comprising tie rods and end parts. Dismantable holding devices for the plug of at least one element are provided at one end part and comprise a threaded connection. They are actuatable without applying a high torque to the sheath of the fuel element and enable the element to be extracted across an end part.

Abstract: For welding a grid formed by sets of plates disposed orthogonally and whose endmost parts are secured to a surround, it is placed in a shaping and mechanically holding frame allowing access to the point to be welded. The frame containing the grid is then placed on a revolving device belonging to a roundabout, at a first welding position and welding is carried out therein on at least one face of the grid by means of a welding member movable in two perpendicular directions for bringing it at right angles to each of the welding points on the face. The frame is then brought to a second welding position in which the plates are welded to the surround by means of a second welding member movable in only one direction, after rotation through 90.degree. of the frame by means of the revolving device; and the operations are repeated as necessary until the whole of the welds have been executed.

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.

Abstract: Apparatus and means for assembling strips in grilles, comprising a carriage (24) displaceable vertically on a sub-frame, and a device (26) displaceable horizontally on the sub-frame parallel to the slots in the strips, and comprising a table equipped for receiving and centering a strip, and for enabling a frame forming an assembly jig to be retained in successive predetermined positions in which the slots in the strips carried by the frame face the path of the strip carried by the movable device.

Abstract: The invention relates to a method for the separation in an induction furnace of a metallic phase and scoriae in a crucible 1 essentially transparent to an electromagnetic field. The method consists of subjecting materials in a first zone 14 to an electromagnetic field of frequency enabling the direct coupling of the inductor 10 with the scoriae, then in a second zone to an electromagnetic field of reduced frequency enabling, under the effect of the centripetal forces produced, the assembling of the metallic phase 28 in the axial region of the crucible.