Abstract: An apparatus (1) for thermal denitration of a uranyl nitrate hydrate to uranium trioxide UO3. The apparatus (1) comprises a burner (114) and a reaction chamber (110) configured to carry out thermal denitration of uranyl nitrate hydrate and to form uranium trioxide UO3 in the form of particles. The apparatus also comprises a separating chamber (120) suitable for separating UO3 particles from the gases resulting from the thermal denitration carried out in the reaction chamber (110), and at least one filter (130) configured for purifying the gases. The separating chamber (120) is a decanting chamber into which the reaction chamber (110) directly opens out. The filter (130) is capable of performing the separation at a temperature greater than or equal to 350° C. The invention also relates to use of such an apparatus, to a thermal denitration process and to UO3 particles obtained by such a process.

Abstract: The invention relates to a smoothing tool (3) configured for smoothing glass frit in a radioactive environment, in an induction-melting cold crucible. Smoothing tool (3) comprising a rod (30), a grid (50) configured to be in contact with glass frit (7) to be smoothed, and at least one vibrator (37, 55, 56) configured to make the grid (50) vibrate. The grid (50) is mechanically connected to the rod (30).

Abstract: A method to activate U3O8 for conversion of this uranium oxide to hydrated UO4 via reaction with hydrogen peroxide H2O2, wherein the following successive steps are performed: a) an aqueous suspension is prepared containing a powder of U3O8 and hydrogen peroxide; b) the aqueous suspension containing a powder of U3O8 and hydrogen peroxide is contacted with ozone, whereby an aqueous suspension is obtained of a powder of activated U3O8; c) optionally the powder of activated U3O8 is separated from the aqueous suspension. A method to convert U3O8 to hydrated UO4 of formula UO4, nH2O where n is 2 or 4, comprising at least one step at which hydrogen peroxide H2O2 is added to the aqueous suspension of a powder of activated U3O8 obtained at the end of step b) of the activation method or to an aqueous suspension prepared by placing in suspension in water the powder of activated U3O8 obtained at the end of step c) of the activation method.

Abstract: Position-indexed storage device comprising a support and a basket installed on the support, the basket comprising a plurality of compartments distributed around a longitudinal axis, the basket comprising a central passage with a longitudinal axis, the support comprising a shaft with a longitudinal axis, the shaft being housed in the passage such that relative displacement is possible between the basket and the support along the longitudinal axis, and mechanical means for displacement of the basket relative to the support by a given angle about the longitudinal axis are supported by the internal surface of the passage and the external surface of the shaft, said mechanical displacement means being actuated in each cycle, each cycle comprising a relative separation or approach displacement along the longitudinal axis of the basket and the support.

Abstract: The present invention relates to a process for sintering a compacted powder of at least one oxide of a metal selected from an actinide and a lanthanide, this process comprising the following successive steps, carried out in a furnace and under an atmosphere comprising an inert gas, dihydrogen and water: (a) a temperature increase from an initial temperature TI up to a hold temperature TP, (b) maintaining the temperature at the hold temperature TP, and (c) a temperature decrease from the hold temperature TP down to a final temperature TF, in which the P(H2)/P(H2O) ratio is such that: 500<P(H2)/P(H2O)?50 000, during step (a), from TI until a first intermediate temperature Ti1 between 1000° C. and TP is reached, and P(H2)/P(H2O)?500, at least during step (c), from a second intermediate temperature Ti2 between TP and 1000° C., until TF is reached.

Abstract: A method for controlling the gain and zero of a multiple pixel photon counter device, and light-measuring system implementing said method. Signals provided by the device are acquired for predefined periods, until a predefined total measurement time is reached, an amplitude histogram is formed from the acquired signals, the positions of two consecutive peaks, measurable on the histogram, are determined, an error signal is produced, which is equal to the deviation between both peaks and, by means of the same, the voltage supplying the device is regulated, so as to keep the deviation equal to a predefined set point.

Abstract: A basket for incinerating waste inside an incinerator for a duration longer than fifteen minutes with no need for waste to be molten earlier, particularly when waste is introduced inside the incinerator. The basket includes mainly of a glass fiber envelope: it is preferably stiffened by a lightweight metal structure located inside or outside the envelope or built into it. A gripping handle is installed on top of the assembly that is stiffened at the top by a metal tube to which a lightweight metal structure is fixed and by a base formed from a drip pan fixed to the base of the lightweight metal structure.

Abstract: The invention relates to gels for detecting and locating radioactive surface contamination of a solid material substrate, particularly via change in the colour of the gels within the visible range or via attenuation, fading, of the colour of the gels, i.e. decoloration of the gels. The invention also relates to a method for detecting and locating radioactive surface contamination of a solid material substrate that uses said gels.

Abstract: A device for measurement of the radiological activity in the bottom of an aqueous medium, comprising a sealed case for a radiological detector, means forming a truncated cone containing a material that allows radiation to be measured by said radiological detector to pass through it, comprising a short base and a long base, the long base forming an input face for the radiation to be measured, this cone being assembled to said case in a sealed manner, the short base being placed on the side of the detector input face, and the long base being designed to be placed facing the bottom of this aqueous medium.

Abstract: A method for sorting, in a continuous flow, contaminated materials, which includes: conveying materials from a point (A) to a point (B) by means of a conveyor; measuring the radioactive activity by means of a first sensor between the points (A) and (B) on the top surface (FSUP) of the first conveyor; and sorting the materials by means of a sorting device. The method may include measuring the radioactive activity of the contaminated material by means of a second sensor, either on the top surface (FSUP) of the conveyor and upstream from the point (A), or below the bottom surface (FINF) of said conveyor; calculating a differential measurement between a measurement from the second sensor and from the first sensor; and restricting the sorting to the comparison between a threshold value and the measurement from the first sensor or the differential measurement.

Abstract: The melting induction furnace comprises, together with a casing (7) to which a lower sole plate (11) is added to form the central part of the structure, a removable inner crucible (1) composed of an internal layer (4) resisting heat and aggressiveness of the molten bath (20), an external layer (6) delimiting the crucible and an insulating intermediate layer (5). The crucible (1) is a disposable crucible and can be stored with its charge in an appropriate container. Heat losses are low, even when the casing (7) is cooled. Stresses due to differential thermal expansions are also very much reduced.

Abstract: The handling device for cases and boxes contained in the cases, comprising a housing intended to receive a case, said housing being closed at a first longitudinal end and open at a second longitudinal end, a holding device (14) mounted at the level of the second end of the housing, the latter comprising two clamping jaws, said clamping jaws applying a clamping force to the case (E), an actuator for opening and closing said jaws, two stop jaws (36, 38), each (36, 38) being supported by a clamping jaw and being articulated in a free manner about and relative to the clamping jaw, springs (40) connecting said stop jaws (36, 38), such that opening of the clamping jaws causes opening of the stop jaws (36, 38) and the stop jaws (36, 38) can be opened independently of the clamping jaws.

Abstract: Device for handling objects in a glove box comprising a carriage (2) to support the objects to be handled, a base (6) relative to which the carriage (2) can be moved along a horizontal axis (X), means of driving the carriage (2) along the first axis (X), these drive means comprising an electric motor (14) arranged such that its drive shaft is orthogonal to the axis (X) and projects opposite the base (6), a transmission shaft (18) parallel to the motor (14), a rack (22) fixed to the base (6) along the axis (X) and a pinion (24) directly fixed in rotation to the transmission shaft (18) and engaging with the rack (22), a transmission belt (20) mechanically connecting the drive shaft of the motor (14) to the transmission shaft (18), the electric motor (14) being declutchable and the carriage possibly being moved manually along the axis (X).

Abstract: A process is described for synthesizing a mixed peroxide or hydroxo-peroxide of an actinyl and at least one cation X1, wherein the actinyl is a uranyl or neptunyl and the at least one cation X1 is a di-, tri- or tetra-charged metal cation. This process includes the reaction in a solvent of a salt of the at least one cation X1 with a compound C2 selected from mixed peroxides and hydroxo-peroxides of the actinyl and of at least one singly charged cation X2, whereby compound C2 is converted to the peroxide or hydroxo-peroxide by replacement of the at least one cation X2 by said at least one cation X1. Also disclosed is a process for synthesizing a mixed oxide of an actinide selected from uranium and neptunium, and of at least one metal able to form a di-, tri- or tetra-charged cation, which implements the preceding synthesis process.

Abstract: A method for processing a spent nuclear fuel is disclosed which includes a step for decontaminating uranium(VI) from one or more actinides(IV) and more specially from neptunium and/or plutonium, by complexing this (these) actinide(s)(IV). This method includes a step for decontaminating uranium (VI) from at least one actinide(IV), which decontaminating step comprises at least one operation for stripping the actinide(IV) from an organic phase, not miscible with water, and wherein uranium(VI) and the actinide(IV) are present, by putting the organic phase into contact with an aqueous phase comprising nitric acid and at least one complexing agent which more strongly complexes actinides(IV) than uranium(VI), and then separating the organic phase from the nitric aqueous phase, wherein the at least one complexing agent is a diglycolamide.

Abstract: The invention relates to a method for preparing a powder of a solid solution of dioxide of uranium and of at least one other actinide and/or lanthanide element comprising a step for combustion of a solution comprising uranyl nitrate and at least one nitrate of the other actinide and/or lanthanide element and nitrogen-containing fuel used according to a specific predetermined amount so as to form at the end of this step, said solid solution.

Abstract: An installation for welding top plugs on to nuclear fuel rods comprising a device for axially holding the rod and setting it in rotation and a weld chamber, where the device comprises a gripper and structure to close the gripper on the rod, where the structure 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 the pusher, and able to rotate freely around a fixed axis orthogonal to the lengthways axis which is not secant with the latter, where the 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: Device for removing an electrode from an electrode holder and/or fitting an electrode into an electrode holder, said electrode holder forming part of a welding device, said device comprising a spent electrode receptacle provided with an orifice and an assembly mounted on said orifice, said assembly comprising a through passage with a longitudinal axis connecting a housing to hold one end of the electrode holder forming a mandrel, and the receptacle, said longitudinal axis being designed to be approximately vertical, means of tightening or loosening an electrode holder mandrel, means of fixing the electrode to said device and means of enabling or disabling dropping of the spent electrode into the receptacle.

Abstract: A method using diglycolamide for increasing the separation factor between americium and curium and/or between lanthanides during an extraction operation. The operation comprising putting an acid aqueous phase, in which are found the americium, curium and/or lanthanides, in contact with an organic phase non-miscible with water, containing at least one extractant in an organic diluent. The aqueous and organic phases are then separated, and the diglycolamide is added to the aqueous phase.

Abstract: A device for measurement of the radiological activity in the bottom of an aqueous medium, comprising a sealed case for a radiological detector, means forming a truncated cone containing a material that allows radiation to be measured by said radiological detector to pass through it, comprising a short base and a long base, the long base forming an input face for the radiation to be measured, this cone being assembled to said case in a sealed manner, the short base being placed on the side of the detector input face, and the long base being designed to be placed facing the bottom of this aqueous medium.