Abstract: A method with which uranium from a natural uranium concentrate may be purified, including a) extracting the uranium present as uranyl nitrate in an aqueous phase A1 resulting from the dissolution of the natural uranium concentrate in nitric acid, by means of an organic phase which contains an extractant in an organic diluent; b) washing the organic phase obtained at the end of step a), with an aqueous phase A2; and c) stripping the uranyl nitrate of the organic phase obtained at the end of step b), by circulating this organic phase in an apparatus, as a counter current against an aqueous phase A3. The extractant is an N,N-dialkylamide and the ratio between the flow rate at which the organic phase obtained at the end of step b) and the aqueous phase A3 circulate in the apparatus where step c) occurs, is greater than 1.

Abstract: A conveyor device has a sequence of two vibrating screens vertically separated (d) from each other and supplying an alignment bowl, to eliminate chips and residue from nuclear fuel pellets stored in bulk in a boat and to align them in order to fill fuel rods. Due to these two screens, pellets are set aside and turned over, and chips are efficiently separated in a pot, without any congestion of the system.

Abstract: A stabilized foam formed from a foaming aqueous solution comprising from 0.1 to 7 mol of one or more decontamination, stripping and/or degreasing reactants per liter of solution and from 0.01 to 15% by weight of a solid stabilizing agent of solid particles type, with respect to the total weight of the solution, and a process for the preparation of said stabilized foam, to its use in decontaminating, stripping and/or degreasing a surface and to a process for decontaminating, stripping and/or degreasing a surface.

Abstract: Angular sectors of a cylindrical wall of a crucible for vitrification of waste, built in steel and subject to high temperatures, are coated with a mixture of mainly glass and ceramic, the coating being subject to a heat treatment comprising a step between 650° C. and 850° C. so as to perform surface melting of the mixture filling the open porosity, improving dielectric strength and the cohesion of the coating, but without producing any excessive thermal expansion or oxidation of the substrate which would lead to fast flaking of the coating.

Abstract: A method with which americium may be selectively recovered from a nitric aqueous phase containing americium, curium and fission products including lanthanides and yttrium, but which is free of uranium, plutonium and neptunium or which only contains these three last elements in trace amounts. The method is applicable for treatment and recycling of irradiated nuclear fuels, in particular for removing americium from raffinates stemming from methods for extracting and purifying uranium and plutonium such as the PUREX and COEX™ methods.

Abstract: A method for regenerating a solid filter containing iodine in the form of silver iodide and/or iodate and possibly molecular iodine physisorbed, in a solid filter containing silver in the form of nitrate. The iodine is extracted from the filter by putting the filter into contact with a basic aqueous solution containing a reducing agent. The extraction is achieved at room temperature, and then the filter is separated from this basic aqueous solution. Next, silver is extracted from the filter by putting the filter into contact with an acid aqueous solution. The filter is then separated from the acid aqueous solution. Finally, the filter is impregnated with silver by putting the filter into contact with a silver nitrate solution and then drying the filter. This method can be used in nuclear installations, notably factories for reprocessing used nuclear fuels.

Abstract: A machine comprising two rollers for ovalizing a nuclear fuel cladding to crush the content thereof allowing its easy release even if the pellets are arranged in the cladding with little clearance. The opposite inclinations of the rollers promote automatic forward travel of the claddings. The opening and the inclination of the claddings lead to release of the crushed fuel. The rollers are biconical, with an input portion of increasing diameter and an output portion of decreasing diameter, to apply sufficient ovalizations to crush the fuel while restoring rotundity to the cladding when it leaves the machine, to facilitate the outflow of debris.

Abstract: A spring mounting device in a cladding tube for nuclear fuel, comprising a spring distributor, a spring loader in the cladding tube, the distributor supplying the springs to the loader, said loader comprising a longitudinal slide to receive the spring, a pusher in order to set the spring into place in the cladding tube and is able to move in the slide, means of displacement of said pusher, said device comprising mechanical means in order to associate the actuation of the means of displacement with that of the spring distributor.

Abstract: The present invention relates to a vacuumable gel and the gel use to decontaminate surfaces, for example, radioactive decontamination. The gel is composed of a colloidal solution comprising: from 5 to 25 wt % of an inorganic viscosity modifier; from 0.01 to 0.2 wt % of a surfactant, preferably, a surfactant in an amount strictly below 0.1 wt %, wt % relative to the total weight of the gel; from 0.5 to 7 mol, per liter of gel, of an inorganic acid or base; and optionally from 0.05 to 1 mol, per liter of gel, of an oxidizer having a standard redox potential Eo greater than 1.4 V in a strong acid medium or of the reduced form of this oxidizer; the remainder being water. The gel may be applied, by spraying, to a surface to be decontaminated, and removed in the form of dry residues by suction or brushing after drying.

Abstract: Method for producing a uranium concentrate in the form of solid particles, by precipitation from a uranium-containing solution using a precipitating agent, in a vertical reactor comprising a base, a top, a central part, an upper part, and a lower part, the solid particles of the uranium concentrate forming a fluidized bed under the action of a rising liquid current which circulates from the base towards the top of the reactor successively passing through the lower part, the central part and the upper part of the reactor, and which is created by introducing a liquid recycling current (flow) at the base of the reactor, said liquid recycling current being tapped at a first determined level (A) in the upper part of the reactor and sent back without settling to the base of the reactor, excess liquid being also evacuated via an overflow located at a second determined level (B) in the upper part of the reactor; a method in which the upper limit (C) of the fluidized bed of solid particles is controlled so that it is

Abstract: A method for treating a nitric aqueous liquid effluent containing nitrates of metals or metalloids, comprising a step for calcination of the effluent in order to convert the nitrates of metals or metalloids into oxides of said metals or metalloids, at least one compound selected from the nitrates of metals or metalloids and the other compounds of the effluent leading upon calcination to a tacky oxide, and a dilution adjuvant leading upon calcination to a non-tacky oxide being added to the effluent prior to the calcination step, a method wherein the dilution adjuvant comprises aluminium nitrate and at least one nitrate selected from iron nitrate and rare earth nitrates.

Abstract: Pellet fabrication device comprising a powder distributor and a table provided with cavities to be filled with powder, on which the distributor moves. The distributor comprises two assemblies of rollers cooperating with rails fixed on the table on each side of the distributor displacement zone, a set of rollers being used to guide displacement of the distributor and a set of rollers being used to press the distributor in contact with the table.

Abstract: An installation for welding top plugs on to nuclear fuel rods comprising a device for axially holding said rod and setting it in rotation and a weld chamber, where said device comprises a gripper and means to close the gripper on the rod, where said means comprise a pusher to apply an axial force on to the gripper, a linear actuator of axis parallel to the lengthways axis of the device, a yoke translationally secured to said pusher, and able to rotate freely around a fixed axis orthogonal to the lengthways axis which is not secant with the latter, where said yoke is connected and able to pivot relative to the linear actuator around a fixed axis parallel to the orthogonal axis such that the linear actuator causes the yoke to rotate around the first orthogonal axis and causes the pusher to slide, closing the gripper on the rod.

Abstract: A cask for loading at least one nuclear fuel assembly in a transport container, including a body with a longitudinal axis (X) capable of sealably covering an upper end of a container, at least one aperture (10) for letting through a fuel assembly, at least one means for connecting to pneumatic confinement means and at least one means (56) capable of maintaining a means (58) for sealing a chamber of the container inside the cask and at a distance from an entrance of said chamber during loading, wherein the maintaining means (56) includes a first arm (60) rotationally mobile around a first axis and a second arm (62) attached to the first arm (60) and rotationally mobile relatively to the first arm, said cask also including external means for controlling the arms (68,86), and wherein the second arm (62) includes a housing (76) for receiving the sealing means.

Abstract: A process which allows separation of americium present in an acid aqueous phase or in an organic phase from the other metal elements also found in this phase, by complexation of the americium with a water-soluble ethylenediamine derivative; and a process for selective recovery of americium from an acid aqueous phase containing, in addition to americium, other metal elements, which comprises the application of this separation process.

Abstract: A method inhibits the formation of zirconium molybdate precipitate in an aqueous solution containing the element molybdenum and the element zirconium by adding a chemical element selected from plutonium, tellurium, antimony and mixtures thereof with the aqueous solution. The method can be used for reprocessing used fuels with the element molybdenum and the element zirconium.

Abstract: A method for measuring the uranium concentration of an aqueous solution including the following successive steps: a) electrochemical reduction towards valence IV, of the uranium present in the aqueous solution with a valence greater than IV, this reduction being implemented at pH<2 and by passing an electrical current in the solution; b) measurement of the absorbance of the solution obtained on completion of step a) at a chosen wavelength between 640 and 660 nm, and preferably 652 nm; and c) determination of the uranium concentration of the aqueous solution by deduction of the uranium concentration of valence (IV) present in the aqueous solution obtained on completion of step a) from measurement of the absorbance obtained in step b).

Abstract: An improved melting furnace including a crucible and a plurality of parallel conductors of identical height surrounding the crucible having at least one descending portion (9) and one ascending portion (10). The benefit from this arrangement is that the conductors all have a portion located at each heating height which guarantees density uniformity of the currents flowing in the conductors even if the load of the crucible has superimposed regions for which the electrical resistivity is different.

Abstract: Equipment to transfer powder from a drum into a tank comprising at least one handling device and one hopper assembly (T) connected to a tank (4). The handling device comprises a hollow cylindrical body intended to surround a drum (2) and to immobilise it to enable it to be turned upside-down, where the drum (2) is open and the powder is contained in at least one sealed bag. The hopper assembly (T) comprises a hopper (60) and a sealed enclosure (62) installed on the upstream end of the hopper, where said enclosure (62) comprises an aperture to enable the hollow cylindrical body loaded with the drum (2) and of the sack of powder to enter, and then, after removal of the hollow cylindrical body loaded with the empty drum (2), to be closed, and to allow the bag to be opened to allow the powder to flow into the hopper (60).

Abstract: The invention relates to a device (1) for the insertion, guidance and evacuation of cylindrical parts to be ground in a centreless grinder (10). According to the invention, micrometric means (4, 40, 41) for adjustment of the alignment of the guides at the entry (3) to and the exit (5) from the guide chute (2) are provided and these micrometric adjustment means are independent from each other. The invention enables very precise adjustment of the alignment and prevents any shift of the parts.