Abstract: A method for the cryogenic grinding of at least one powder comprising the following steps: (a) introducing a cryogenic fluid into an attrition mill comprising attrition means, (b) introducing the powder or powders into the attrition mill, and (c) setting the attrition mill in rotational motion, and wherein—the ratio VMA/(VMA+VFC) of the volume of the attrition means VMA to the sum of the volume of the attrition means VMA and the volume of the cryogenic fluid VFC is comprised between 0.2 and 0.8, and the rotational speed of the attrition mill during step (c) is between 100 rpm and 20,000 rpm. Further, particles of metal or metal alloy, to the use thereof, to a coating method employing them and to the use of such a coated material.

Abstract: A device for granulating powders by cryogenic atomisation, characterised in that it comprises: a device for mixing powders by cryogenic fluid, comprising at least one chamber for mixing powders, comprising a cryogenic fluid; and a device for atomising a suspension of powders mixed by the device for mixing powders in order to allow a granulation of the powders, comprising a way of fractionating the suspension of powders making it possible to adjust the size of the droplets of powders to be atomised, and a method for adjusting the moisture of the mixed powders and/or the moisture of the atomisation atmosphere.

Abstract: A device for mixing powders by cryogenic fluid, characterised in that it comprises at least: a chamber for mixing powders, comprising a cryogenic fluid; a chamber for supplying powders in order to allow the powders to be introduced into the mixing chamber; means for agitation in the mixing chamber so as to allow the mixing of the powders placed in suspension in the cryogenic fluid.

Abstract: A device for mixing powders by a cryogenic fluid, characterised in that it comprises: a chamber for mixing the powders, comprising a cryogenic fluid, provided with means for forming a fluidised powder bed; a chamber for supplying powders in order to allow the powders to be introduced into the mixing chamber; a chamber for supplying cryogenic fluid in order to allow the cryogenic fluid to be introduced into the mixing chamber; a system for generating vibrations in the fluidised powder bed; and a system for controlling the system for generating vibrations.

Abstract: A device for transferring a given powder or a mixture of given powders contained in a container including a side wall and at least one discharge opening, the container with axisymmetric shape having an axis of rotation being arranged in the transfer device such that the discharge opening thereof is located in a lower portion of the container, the transfer device including rotating the container about the axis thereof, on which the discharge opening is located and control for controlling the rotation such that the to rotation imposes on at least one portion of the side wall of the container, referred to as movable portion, a first moving phase wherein an acceleration no lower than a minimum acceleration is capable of causing the powder to slide relative to the movable portion.

Abstract: A device for mixing powders by cryogenic fluid, characterised in that it comprises at least: a chamber for mixing powders, comprising a cryogenic fluid; a chamber for supplying powders in order to allow the powders to be introduced into the mixing chamber; means for agitation in the mixing chamber so as to allow the mixing of the powders placed in suspension in the cryogenic fluid.

Abstract: A device for mixing powders by a cryogenic fluid, characterised in that it comprises: a chamber for mixing the powders, comprising a cryogenic fluid, provided with means for forming a fluidised powder bed; a chamber for supplying powders in order to allow the powders to be introduced into the mixing chamber; a chamber for supplying cryogenic fluid in order to allow the cryogenic fluid to be introduced into the mixing chamber; a system for generating vibrations in the fluidised powder bed; and a system for controlling the system for generating vibrations.

Abstract: A device for granulating powders by cryogenic atomisation, characterised in that it comprises: a device for mixing powders by cryogenic fluid, comprising at least one chamber for mixing powders, comprising a cryogenic fluid; and a device for atomising a suspension of powders mixed by the device for mixing powders in order to allow a granulation of the powders, comprising a way of fractionating the suspension of powders making it possible to adjust the size of the droplets of powders to be atomised, and a method for adjusting the moisture of the mixed powders and/or the moisture of the atomisation atmosphere.

Abstract: The invention relates to a jet spouted bed reactor, comprising a cylindrical area, a gas injection pipe at the base of the cylindrical area, and a transition area, connecting the upper end of the pipe to the base of the cylindrical area, this transition area having a convex profile in a plane extending through the axis (YY?) of flow of a fluid in the pipe.

Abstract: A process for generating droplets with a modulatable droplet size distribution, comprises: making a stream of liquid strike a support with a given relative impact velocity; making said support vibrate at at least one vibration frequency; heating said support to a impact temperature such that the liquid film formed by the impact and made to vibrate is heated to a principal temperature to form in combination what are called principal droplets from said film; and transporting said droplets via a transfer/braking/sorting system to a liquid for precipitating the principal droplets, said transportation being carried out at a transportation temperature, all of these parameters, namely the relative impact velocity, the vibration frequency, the principal temperature and the transportation temperature allowing the droplet size of said formed principal droplets and the velocity of the latter to be modulated. A device allowing the process to be implemented is also provided.

Abstract: A device for transferring a given powder or a mixture of given powders contained in a container including a side wall and at least one discharge opening, the container with axisymmetric shape having an axis of rotation being arranged in the transfer device such that the discharge opening thereof is located in a lower portion of the container, the transfer device including rotating the container about the axis thereof, on which the discharge opening is located and control for controlling the rotation such that the rotation impose on at least one portion of the side wall of the container, referred to as movable portion, a first moving phase wherein an acceleration no lower than a minimum acceleration is capable of causing the powder to slide relative to the movable portion.

Abstract: A process for chemical stabilization of a uranium carbide composite material: UCx+yC with x?1 and y>0, placed in a stabilization chamber, comprises: a rise in chamber internal temperature for oxidation of the compound based on uranium carbide between approximately 380° C. and 550° C., the chamber being fed with a neutral gas; isothermal oxidative treatment at the oxidation temperature, the chamber being placed under O2 partial pressure; controlling completion of stabilization of the compound, comprising monitoring the amount of molecular oxygen consumed and/or carbon dioxide or carbon dioxide and carbon monoxide given off, until achievement of an input set-point value for the amount of molecular oxygen, of a minimum threshold value for the amount of carbon dioxide or minimum threshold values for the carbon dioxide and carbon monoxide. A device implements the process.

Abstract: The present invention relates to a method for preparation of a powder comprising at least one carbide of at least one metal, comprising the steps consisting of: (a) preparing a solution comprising at least one organic gelling agent and at least one inorganic salt of at least one metal in a solvent; (b) modifying the pH of the solution prepared in step (a) in such a way as to precipitate said at least one metal and to obtain a colloidal suspension comprising nanoparticles of oxyhydroxides of said at least one metal; (c) removing the solvent from the colloidal suspension obtained in step (b) by which means a precursor of at least one carbide of at least one metal is obtained; and (d) subjecting the precursor obtained in step (c) to a thermal treatment in order to transform same into a powder comprising at least one carbide of at least one metal. The present invention also relates to the powder thus prepared and the various uses thereof.

Abstract: The invention relates to a powder of an alloy based on uranium and molybdenum in a metastable ? phase, which is formed of particles which have an elongation index at least equal to 1.1, a non-zero closed porosity value and which are composed of grains having a molybdenum content, for which the variations within the same grain are of at most 1% by mass. It also relates to a method allowing preparation of this alloy powder as well as to the use of said powder for manufacturing nuclear fuels and targets for producing radioisotopes. Applications: Manufacturing of nuclear fuels, notably for experiment nuclear reactors; manufacturing of targets for producing radioisotopes, notably for the medical industry.

Abstract: A composition filled with actinide powder, comprising an organic matrix and an actinide powder or a mixture of actinide powders, comprises at least: a plasticizer comprising an alkane whose longest radical chain comprises at least a few tens of carbon atoms and is in a volume content of between 20% and 70% of the total volume of the organic compounds alone; a binder comprising at least one polyolefinic polymer and which is in a volume content of between 20% and 50% of the total volume of the organic compounds alone; a dispersant comprising a carboxylic acid or salts thereof, the volume content of which is less than 10% of the total volume of the organic compounds alone; said actinide powder or said mixture of actinide powders represent between 40% and 65% of the volume of the filled matrix.

Abstract: A method for preparing a powder of an alloy based on uranium and molybdenum in a metastable ? phase is provided, which comprises: a) putting at least one first reagent selected from uranium oxides and mixtures thereof, uranium fluorides and mixtures thereof, into contact with a second reagent consisting in molybdenum and a third reagent consisting in a reducing metal, the first, second and third reagents being in a divided form; b) reacting the reagents at a temperature?the melting temperature of the third reagent and under an inert atmosphere, whereby this reaction leads to the formation of the alloy comprising uranium and molybdenum in the form of a powder, for which the particles are covered with a reducing metal oxide or fluoride layer; c) cooling the so formed powder at a rate at least equal to 450° C./hour; and d) removing the reducing metal oxide or fluoride layer which covers the particles of the powder of the alloy comprising uranium and molybdenum.

Abstract: A supplemented nuclear fuel comprises a nuclear fuel of oxide type which generates fission products such as tellurium, cesium and iodine, which generate via chemical interaction species that are potentially corrosive, supplemented with at least one redox system comprising a first and second species comprising a common element having a different degree of oxidation in each of the two species, the system having an oxygen potential curve as a function of the temperature that is within an interval delimited by: an upper limit: the curve of coexistence of the chemical species I2Te (g) and CsI (g) at the same partial pressure imposed by the equilibrium between CsI (l) and CsI (g), approximated between 1000° C. and 2000° C. by a straight line segment whose ends PO2/11 and PO2/12 have the coordinates: PO2/11 (T=1000° C.)??370 kJ/molO2 and PO2/12 (T=2000° C.)??230 kJ/molO2; and a lower limit: the curve of oxygen potential of the system (Cs2MoO4/Cs+Mo) approximated between 1000° C. and 2000° C.

Abstract: A composition filled with actinide powder, comprising an organic matrix and an actinide powder or a mixture of actinide powders, comprises at least: a plasticizer comprising an alkane whose longest radical chain comprises at least a few tens of carbon atoms and is in a volume content of between 20% and 70% of the total volume of the organic compounds alone; a binder comprising at least one aromatic polymer and/or polymethyl methacrylate and which is in a volume content of between 20% and 50% of the total volume of the organic compounds alone; a dispersant comprising a carboxylic acid or salts thereof, the volume content of which is less than 10% of the total volume of the organic compounds alone; said actinide powder or said mixture of actinide powders represent between 40% and 65% of the volume of the filled matrix.

Abstract: A process for generating droplets with a modulatable droplet size distribution, comprises: making a stream of liquid strike a support with a given relative impact velocity; making said support vibrate at at least one vibration frequency; heating said support to a impact temperature such that the liquid film formed by the impact and made to vibrate is heated to a principal temperature to form in combination what are called principal droplets from said film; and transporting said droplets via a transfer/braking/sorting system to a liquid for precipitating the principal droplets, said transportation being carried out at a transportation temperature, all of these parameters, namely the relative impact velocity, the vibration frequency, the principal temperature and the transportation temperature allowing the droplet size of said formed principal droplets and the velocity of the latter to be modulated. A device allowing the process to be implemented is also provided.

Abstract: The invention relates to a jet spouted bed reactor, comprising a cylindrical area, a gas injection pipe at the base of the cylindrical area, and a transition area, connecting the upper end of the pipe to the base of the cylindrical area, this transition area having a convex profile in a plane extending through the axis (YY?) of flow of a fluid in the pipe.