Abstract: The invention relates to a device for dressing a grinding wheel, comprising a sleeve to hold a corundum rod laterally and to guide it along its longitudinal axis, a ram to apply constant thrust force onto the corundum rod held in place and guided in the sleeve, to bring it into contact with the grinding wheel, means of rigidly connecting the ram shaft to the end of the corundum rod, and linear guide means for the sleeve for translating the corundum rod parallel to the axis of the grinding wheel while keeping the rod pressed against the grinding wheel with a constant force. Application to a centerless grinder in which the grinding wheel is used to grind nuclear fuel pellets.

Abstract: A system for filling a jar with powdery material, for example for the manufacture of nuclear fuel, including a device for connection between the jar and a material feed system, where the device includes: a stationary connection portion connected to the feed system, a connection portion which moves relative to the stationary connection portion intended to be connected to the container's filling orifice, where the moving connection portion includes in the area of a downstream end a lip seal to achieve a tight connection by contact with the contours of the jar's filling orifice and where the said downstream end is connected to the stationary connection portion by a bellows so as to provide mechanical disengagement between the downstream end of the moving connection portion and the stationary connection portion.

Abstract: A nuclear fuel assembly tie plate is provided. The nuclear fuel assembly tie plate is formed by intersecting strips delimiting between them tubular guide cells each for allowing a fuel rod to extend through the tie plate. The strips delimit between them tubular flow cells separate from the guide cells, each flow cell for allowing coolant flow through the tie plate. Guide cells and flow cells are arranged at nodes of a lattice defined by a repeating pattern comprising four corner nodes in a square lattice arrangement and a central node at the center of the four corner nodes, with one guide cell at each corner nodes, separated by a pair of parallel spaced strips intersecting a pair of parallel spaced strips, the two pairs of strips delimiting a four-walled central flow cell at the center node.

Abstract: The invention relates to the use of a mixture comprising erbium and praseodymium as a radiation attenuating composition, i.e. as a composition that can attenuate ionizing radiation, in particular X- and gamma-type electromagnetic radiation. The invention also relates to a radiation attenuating material comprising an erbium- and praseodymium-based composition, as well as a protective article which provides group or individual protection against ionizing radiation and comprises said material. The invention is suitable for use in nuclear medicine (scintigraphy, radiotherapy, etc.), radiology, medical imaging, the nuclear industry, etc.

Abstract: A method for producing synthetic hydrocarbons from at least one carbonaceous material is provided. The method includes evaluating the resources of the carbonaceous material available on a determined territory; determining from the resources a total production capacity of synthetic hydrocarbons; determining from the total production capacity, a number of elementary production units required for obtaining the total production capacity, each elementary production unit having an elementary production capacity between a 100 and a 1,000 barrels a day of synthetic hydrocarbons; building the number of elementary production units on the territory; transporting the carbonaceous material from the territory as far as the elementary production units; producing the synthetic hydrocarbons in the elementary production units from the transported carbonaceous material.

Abstract: A method of operating a nuclear reactor is provided. The method includes defining a layer increment of a deposit layer modeling a deposit on a heat transfer surface of the nuclear reactor; periodically updating a thickness of the deposit layer by adding the layer increment to the deposit layer; recalculating properties of the deposit layer after each layer increment is added to the deposit layer; determining a temperature related variable of the heat transfer surface as a function of the recalculated properties of the deposit layer; and altering operation of the nuclear reactor when the temperature related variable of the heat transfer surface reaches a predetermined value. A method of modeling a deposit on a heat transfer surface of a nuclear reactor is also provided.

Abstract: Method of stabilizing radium present in radium-containing effluent, in which the effluent and a metal chloride are mixed, then the previously obtained mixture is reacted with a sulfate ion to obtain effluent containing stabilized radium. The chloride can be a barium, strontium or lead chloride. The sulfate ion can be supplied by the addition of sulfuric acid, sulfuric anhydride, soluable sulfate or soluble sulfate salt. The method applies in particular to the treatment of solid radium-containing effluents or effluents containing substances in suspension coming from chemistry or metallurgy of zirconium or treatment of uranium-containing minerals.

Abstract: A method for manufacturing a bi-material sleeve is provided. The sleeve includes an annular outer sleeve and an annular inner sleeve bonded to each other. The bottom pouring of the outer sleeve is carried out in a casting space delimited by a wall of a first ingot mold and by an outer upwardly moveable wall of a second ingot mold concentric with the first. The moveable wall of the second ingot mold is raised so as to uncover the skin of the outer sleeve which has solidified thereagainst. The bottom pouring and the solidification of the inner sleeve are carried out in a casting space delimited by said skin and an inner stationary wall of said second ingot mold, the bonding of both sleeves being effected by diffusion between said sleeves. Forging and/or machining of one of said bonded sleeves are optionally carried out. A device for using this method and a sleeve produced by this method are also provided.

Abstract: A nuclear power plant with an improved cooling system using nanoparticles in solid or fluid form is provided. The nanoparticles are delivered in locations such as the cold leg accumulator and high and low pressure pumps of an emergency core cooling system. Motor driven valves and pressurization can aid in the delivery. Methods for providing the nanoparticles are also provided.

Abstract: A device for changing the electrode of an electrode-holder tool of a welding device, with a first part configured to house an electrode-holder tool and including means to prevent the electrode-holder tool from moving, and a second part installed around the first part and covering the part of the electrode protruding outside the first part, where the second part can be separated from the first part by sliding along the electrode, and is able to rotate relative to the fixed part when it surrounds it, and where the second part is configured to tighten or untighten the mandrel and to attach the electrode and the second part, enabling it to be removed from the mandrel when the first part and the second part are separated.

Abstract: An assembly for producing at least one synthetic hydrocarbon from at least one inflowing stream of carbon monoxide and one inflowing stream of carbon dioxide is provided. The assembly includes an electrolyzer provided for producing a first stream of hydrogen, a first conversion unit provided for producing an intermediate stream of carbon monoxide from at least one portion of the inflowing stream of carbon dioxide and hydrogen, a reactor for synthesizing said synthetic hydrocarbon; a second conversion unit provided for producing a second stream of hydrogen from carbon monoxide and water, the second hydrogen stream being directed towards the synthesis reactor; a guide assembly provided for selectively distributing the inflowing stream of carbon monoxide between the second conversion unit and the synthesis reactor, and for selectively distributing the first hydrogen stream between the first conversion unit and the synthesis reactor; a control unit provided for controlling the guide assembly.

Abstract: Using crystalline silica, mixed with cement powder, to reduce the heating of the cement paste caused by the hydration of said powder, during a process of packaging of radioactive waste, a formulation for the packaging of radioactive waste by cementing, which comprises such silica, a method for packaging radioactive waste implementing this formulation, and a package for packaging of radioactive waste which is obtained by this method.

Abstract: A fuel element handling system having a gripping device, the structure of which can be pushed in the horizontal position and uncoupled from the handling system if a failure occurs, uncoupling releasing the load formed by the fuel elements and their gripped support and putting them in a safe situation.

Abstract: The invention relates to a method for optimizing the conductivity provided by the displacement of H+ protons and/or OH? ions in a conductive membrane made of a material permitting the insertion of steam into said membrane, wherein said method comprises the step of inserting under pressure gaseous flow containing the steam into said membrane in order to force said steam into said membrane under a certain partial pressure so as to obtained the desired conductivity at a given temperature, said partial pressure being higher than or equal to 1 bar, a drop in the operational temperature being compensated by an increase in said partial pressure in order to obtain the same desired conductivity. The invention can be used in particularly interesting applications in the fields of high-temperature water electrolysis for producing hydrogen, of the manufacture of fuel cells using hydrogen fuel, and of hydrogen separation and purification.

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: A method for preparing an oxalate of one or more actinides for processing and recycling nuclear fuel, comprising: the precipitation of said actinide or the coprecipitation of said actinides in the form of oxalate particles by bringing into contact an aqueous solution containing the actinide(s) with an aqueous solution of oxalic acid or of an oxalic acid salt; and the collection of the resulting oxalate particles; characterized in that the precipitation or coprecipitation is carried out in fluidized bed.

Abstract: A pressurizer is for a pressurized water nuclear power plant and it includes an upper cap provided with a tube; an end piece connected to the tube using a weld; and a sleeve protecting the weld, disposed inside the tube. The protective sleeve is mounted in a removable manner, such that the thermal sleeve is removed.

Abstract: The container is comprised of a side wall of which the end edges are each provided with a blocking member, of which at least one is inserted in order to close an opening. The peripheral outline of the inserted blocking member and the interior outline of the associated end edge of the side wall have generally complementary shapes on at least one portion of their respective heights, in such a way that said inserted blocking member comes to be housed on at least one portion of its height in the space defined by said end edge of the side wall and comes to bear against said end edge by adjusting lugs in recesses of complementary shape. The inclined joining surfaces form an angle from 20° to 40° with the axis of the container.

Abstract: The present invention provides a drain plug assembly that prevents significant quantities of corium from entering the drain line. By protecting the drain line, essentially no high-activity fission products would be released to the reactor building or the environment during a severe accident. The ceramic drain plug assembly includes a drain plug base and a drain plug supported by a steel pedestal. The lower surface of the plug has a spherical shape such that the plug can be positioned within the base to block access to the drain opening provided in a central portion of the base. During normal operation conditions, the plug is retained above the base by the pedestal. During a severe accident, when corium comes into contact with the pedestal, it will melt rapidly and the drain plug will drop by gravity, effectively closing the sump drain opening and preventing the flow of corium into the drain line.

Abstract: A device for measuring and correcting a parallelism error of an upper plug end of a nuclear fuel rod comprising mechanisms for measuring a parallelism error and for correcting said error, and a mechanism for positioning said device on the fuel rod and cooperating with a rack on which the fuel rod is stored, said correction means being arranged opposite the measuring mechanism relative to the location of the fuel rod, in order to allow a measurement of the parallelism error during correction of said error.