Abstract: The present invention relates to a method of transforming plutonium oxalate into plutonium oxide by drying and then calcining. In said method, in a characteristic manner, the operations of drying and calcining are implemented continuously, in the presence of oxygen and with gas extraction, in two adjacent zones of a single apparatus, e.g. of the screw oven type, that is maintained at negative pressure. The present invention also provides apparatus suitable for implementing said method.

Abstract: The subject of the present invention is:

Abstract: A device for the controlled admission of a noxious powder into a box which includes a body having an open lower part that terminates in a sealing skirt. The body is connected to a powder inlet pipe and to a gas extraction pipe. A movable valve is disposed in the body. The valve is controlled by a magnetic device, and cooperates with the sealing skirt. A housing is fixed on the lower part of the body. The housing is open in its central part to allow the passage of the box therethrough and comprises a retractable device which ensures grip and transfer of the lid of the box. The device also includes means for detecting the quantity of powder in the box, and at least one ventilation circuit ensuring, at the level of the circumference of the opening of said housing and/or at the level of the sealing skirt, evacuation towards a treatment unit of that part of the powder which might be located at those levels.

Abstract: The device comprises a moving assembly (24) designed to be placed in an operating position in which said assembly (24) is over the opening (12e) of a receptacle (12) filled with a viscous material, first motor means (32) and a first guide system (30a, 34a, 42) serve to impart vertical translation movement to said assembly (24) relative to said receptacle (12), and variable-speed, second motor means (48) and a second guide system (54) serve to impart rotary motion to a moving subassembly (26) belonging to said assembly (24). Said subassembly (26) has a vertical shaft whose top portion (46a) is secured to said second motor means (48), and a rule (22) connected to the bottom portion (46b) of said shaft, the length of the rule being substantially equal to the radius of said opening (12e) and the rule having a bottom surface presenting a horizontal longitudinal portion designed to level the top surface (14a) of the viscous material.

Abstract: The present invention provides a vapor-liquid (V-L) ejector with a removable nozzle (2) in which the internal structure has been modified and improved concerning the clearance that exists to enable said nozzle (2) to be engaged in the body (10) of said ejector (1). The invention also provides a nozzle (2) for such an ejector (1).

Abstract: The powder homogenizing apparatus of the invention comprises a cylindrical shell with a circular section and a substantially horizontal axis, an assembly of cylindrical drums disposed inside the shell and comprising an inner drum and an outer drum, the external face of the cylindrical wall of said outer drum being overlaid with blades, which drum assembly can homogenize the powder contained in the annular space formed between the outer drum and the shell, a space of revolution being formed between said inner and outer drums, and a shaft on which said cylindrical drum assembly is mounted in integral manner, said shaft being hollow and connected outside the shell to a cold air supply system and also connected to an air exhaust system outside the shell; drive means for rotating said shaft are also provided.

Abstract: The present invention relates to a method for the continuous separation of caesium, strontium and transuranium elements contained in sodium waste which comprises the use of NaTPB, and to a device for the implementation of this method. The method of the invention comprises, in line, the following steps: (a) filling at least one of at least two feed tanks with the waste; (b) analysis of the content of Cs+, Sr++, Na+ and transuranium elements in the waste; (c) pre-treatment, adapted in relation to analysis results, of the solution in the feed tank intended to insolubilise the strontium and transuranium elements; (e1) a first caesium separation treatment; and e1a) a second caesium separation treatment, the method being conducted in continuous manner by means of the alternate use of the feed tanks.

Abstract: The stirrer comprises a driving magnetic portion (13) and a driven magnetic portion (14). The driven portion is for placing on the bottom of a receptacle (51) containing a liquid to be stirred. The driving portion (13) is controlled so as to drive the driven portion (14) in rotation about a predetermined axis of rotation (81) by means of magnetic coupling with the driving portion. The stirrer is characterized in that the driving and driven portions are configured in such a manner as to encourage the field lines (15) that result from the magnetic coupling to extend substantially perpendicularly to the axis of rotation in the vicinity of the driven portion. Axial attraction between the driving and driven portions is thus considerably reduced for given torque transmission to the driven portion, such that the driven portion (14) and the bottom of the receptacle (51) are subject to less wear during rotation of the driven portion.

Abstract: The scales include a tray (1) placed on a base (3) and lifted by an air cushion, with no mechanical connection with the base (3). The weight of an object (21) laid on the tray (1) varies the air cushion pressure, and the measurement of this pressure by an external sensor (19) is straightforward and gives the weight of the object (21) once a law of correlation has been determined. Lateral pipes enable gas to be blown against a flange (2) of the tray (1) and thus horizontal displacements of the tray and friction to be avoided. Several vertical pipes are generally provided so as to reduce tray (1) tipping after the object (21) has been thrown off centre, the weight being then given by the sum of the measurements of each vertical pipe.

Abstract: The present invention relates to a method and apparatus for rectifying cylindrical articles, in particular nuclear fuel pellets. In said method, in characteristic manner, the dust generated by the rectification by a working grind wheel acting on said pellets remains confined and practically all of it is entrained beside said working grind wheel so as to be taken away by forced suction.

Abstract: The present invention relates to a rotating device for continuously filtering a liquid such as a solution containing a precipitate.

Abstract: A vertical flow path in a pipe is delimited by channels (3) disposed at an angle. The inclined channels produce a zigzag flow in a mixture of powders which follow the flow path. The zigzag flow causes stirring to maintain homogeneity of the mixture even if its components have very different physical characteristics.

Abstract: The present invention relates to a degreasing composition, to a liquid, to a gel and to a degreasing foam which comprise said composition. The composition according to the invention comprises a base, a polyethoxylated fatty alcohol, saturated or unsaturated, a copolymer of ethylene oxide and propylene oxide, and water. The invention also relates to a degreasing and/or decontamination process of a surface using said composition, said liquid, said gel, and/or said degreasing foam.

Abstract: The liquid to be measured flows through a flow-pipe and bathes the end (1) of a pivoting probe in a spectrophotometric cell (2). One measuring surface (15) of the probe (2) remains immersed in the liquid whose level is advantageously assured by an overflow barrier (19); but when the probe has pivoted, the measuring surface opens onto a duct (23) in which a rinsing liquid flows and leads into the flow-pipe and cleans it. This rinsing is quick and safe and requires no dismounting of the probe. The invention applies in particular to liquids containing radioactive products such as uranium and/or plutonium.

Abstract: The powder mixing apparatus comprises a circular section cylindrical body having a longitudinal axis that is substantially horizontal, the body being leakproof and having two disk-shaped walls and an annular wall, the apparatus having a disk placed coaxially inside said body, the edge of said disk being substantially in contact with the annular wall so as to subdivide said body into two cylindrical compartments of substantially equal volume, said disk being provided on each of its faces with at least one blade for guiding said powder during rotation of said disk to a transfer orifice passing through said disk so as to enable at least a portion of the powder contained in one compartment to pass into the other compartment on each revolution of the disk, said blades being angularly offset, a horizontal drive shaft secured to the center of said disk serving to rotate said disk, and motor means serving to drive said drive shaft.

Abstract: A rotary powder dispenser disposed between a top inlet pipe and at least two bottom outlet pipes includes a casing (1) connected at its top to an inlet via which the flow of powder is taken in, and at its bottom to outlets via which the flow is delivered, the casing (1) being formed of a shell (2) and of a removable base (3); a rotary plug (8) that is disposed in the casing, that is of generally cylindrical shape, and that can turn about its own axis, the plug being provided with an internal duct (11) that slopes relative to its axis so as to enable the powder to flow through it under gravity, with a ring of gear teeth (12) that co-operates with a worm screw (12a) to rotate said plug, and with a cam (13) that co-operates with at least one pusher (14, 15) external to the plug to determine the exact position of the plug; and at least one sealing system (9, 10) disposed between the plug (8) and the casing (1).

Abstract: In order to control the perpendicularity of a component (10) such as a nuclear fuel pellet, this component is placed upon a support plane and measurements are taken, by means of two pairs of laser micrometers (A1, A2; B1, B2), of the distances separating diametrically opposed generators of the component from a rod of reference (T, T′), at two different levels and in two measuring planes (P, P′) perpendicular to each other. From this is derived a maximum out-of-true perpendicularity of the component being controlled.

Abstract: Process and device for controlling force applied on a fuel assembly in a transport container.

Abstract: The present invention relates to a method for the continuous separation of caesium, strontium and transuranium elements contained in sodium waste which comprises the use of NaTPB, and to a device for the implementation of this method.

Abstract: This invention relates to an electrolytic method for the selective recovery and recycling of silver from a nitric acid solution containing it in the form of Ag(I), this method comprising successive steps of electro-deposition of the silver in the form of silver metal Ag(0), and then of redissolution of the deposited silver Ag(0), to give a final solution of Ag(I) in which the step of electro-deposition is carried out at a prescribed current and the successive steps of electro-deposition of the silver and of redissolution of the deposited silver are carried out in the same apparatus. The invention is applicable particularly to the selective recovery of Ag(I) by reduction to Ag metal from nitric acid solutions arising from the processing of plutonium containing waste in plants for the reprocessing of nuclear fuels and to the redissolution of the silver metal to form Ag(I) with the purpose of recycling it to an upstream point of the method.