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 fixed cluster for the core of pressurized-water nuclear reactor including rods and a holder for rods. The holder includes: an upper head; fins extending radially towards the outside from the upper head; systems for mounting the rods and distributed on the fins; and at least two abutment elements on the upper plate of the core, each of the abutment elements protruding longitudinally from a respective fin beyond the mounting systems so as to be vertically oriented towards the top when the fixed cluster is provided on a nuclear fuel assembly.

Abstract: A process of cleaning resin out of an electrical generator parallel ring is provided. The process includes inserting a cleaning ball mounted on a shaft into the parallel ring; verifying a location of the cleaning ball; rotating the shaft; measuring a rotational speed of the cleaning ball with a tachometer; and removing resin with the cleaning ball.

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 leak detecting apparatus for detecting flaws in a surface submerged in liquid is provided that includes a vacuum head for contacting the surface and forming a vacuum chamber filled with liquid between the surface and the vacuum head, the vacuum head including a multi-surface elastomer seal for contacting the surface; and a vacuum generator for pulling gas through a flaw in the surface into the vacuum head and to the gas separation chamber so as to displace the liquid from the gas separation chamber. A method for detecting flaws in a surface submerged in liquid is also provided.

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: The present invention provides a method of operating a Boiling Water Reactor, having the steps of analyzing LPRM signals for oscilliatory behavior indicative of neutron-flux-coupled density wave oscillations, determining if oscilliatory behavior is present in the signals; initiating a reactor protective corrective action if the oscilliatory behavior is determined, and in addition, initiating corrective actions if neutron uncoupled oscillations are possible. Detecting the later is performed through analytically determined exclusion zone on the power flow map or by on-line stability calculations for several high power channels.

Abstract: A method for design of a fuel assembly for nuclear reactors, including structural components made from zirconium alloy: the mean uniaxial tensile or compressive stress to which the components are subjected during the assembly life is calculated, the zirconium alloy of which the components are made is selected according to the following criteria: those components subjected to an axial or transverse compressive stress of between ?10 et ?20 MPa are made from an alloy with a content of Sn between Sn=(=0.025??0.25)% and Sn=?0.05?%: those components subjected to such a stress of between 0 et ?10 MPa are made from an alloy the Sn content of which is between Sn=traces and Sn=(0.05?+1)%: those components subjected to such a stress of between 0 and +10 MPa are made from an alloy the Sn content of which is between Sn=0.05% and Sn=(0.07?+1)%: and those components subjected to such a stress of between +10 and +20 MPa are made from an alloy the content of SN of which is between 0.05% and 1.70%.

Abstract: A process of collecting and manipulating data to measure the gap between structural components of a piece of equipment or a system is disclosed and claimed. The technique uses ultrasonic zero degree longitudinal waveforms to measure the gap. The technique subtracts the average of two adjacent waveforms from the waveform being processed to remove data from reflections from the components to reveal the reflections generated by the gap.

Abstract: A fuel assembly for a light water reactor contains a fuel rod cluster and a spacer that has a number of cells, bounded by webs for laterally holding fuel rods. A damaged region including at least one damaged cell is present in an edge region of a spacer. There being fastened above or below the damaged region on the spacer with the aid of at least one connecting part is a replacement assembly that contains at least a number of cells that corresponds to the number of the damaged cells, at least a portion of the cells being traversed by fuel rods. A method for repairing the light water reactor fuel assembly in the case of which fixed above or below the damaged region on the spacer is a replacement assembly that takes over the holding function at least of one defective cell.

Abstract: A nuclear power station component is provided. The nuclear power station includes a metal structure having an external surface; at least one marking placed on the external surface and encoding information related to the component. The marking includes a plurality of luminescent nanoparticles, each provided to emit optical radiation having a certain emission wavelength when said luminescent nanoparticle is excited with optical radiation having a certain emission wavelength.

Abstract: A position measuring system detects an extreme position of a guide rod which extends along a path that is rectilinear relative to a guide system and can be moved along the rectilinear path, wherein the system operates reliably, and requires a minimum of electrical lines. The position measuring system is equipped with a plurality of sensor elements and a magnetic element, wherein the magnetic element is configured to form a magnetic field. The magnetic element is connected to the guide rod. Each sensor element is configured to detect a magnetic field within a detection region, a field strength of the magnetic field being greater at the location of the sensor element than a predefined threshold value. At least one sensor element is connected to the guide system and is arranged in an environment of the path. A corresponding measuring method uses the position measuring system to detect the extreme positions.

Abstract: A motor operated valve diagnostic data acquisition system including: a motor operated valve assembly; a transmitter, the transmitter being permanently connected in a housing of a motor operated valve assembly; a receiver, the transmitter transmitting signals to the receiver via motor operated valve cables, the cables being existing motor operated valve cables; and electronic circuitry connected to the receiver, the electronic circuitry processing the signals received by the receiver.

Abstract: The invention is principally directed to a reduced order model, XEDOR, facilitating the prediction of and the diagnostics of pellet-clad interaction stress-corrosion-cracking failure of nuclear fuel rods. The invention more particularly relates to assessment of susceptibility to PCI failure for guidance in the design of fuel loading in nuclear reactors. The invention additionally relates to the protection against PCI failure by providing operational information to operators of a nuclear reactor during power maneuvering, including predictive calculations prior to executing power maneuvers. Additionally, the invention relates to the diagnostics of an event suggesting a possible PCI cladding failure.

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 nuclear fuel assembly spacer grid defining a lattice of cells for receiving fuel rods is provided. The spacer grid includes a peripheral band composed of at least one peripheral strip delimiting a portion of the peripheral contour of the spacer grid, and at least one spacer grid positioning spring elastically deformable and formed in the peripheral band.

Abstract: A method for machining a sealing seat of a shut-off valve in a power generating or industrial plant. An upper valve part and the internal housing fittings are removed from the housing of the shut-off valve to thereby expose a housing opening. A clamping device with a counter-bearing is introduced through the housing opening into the connection pipe and fastened to its inner wall. A machine tool with a bearing is introduced through the housing opening and mounted with its bearing on the counter-bearing. A machining step is carried out with the machine tool on the sealing seat. Then the machine tool is detached and removed through the housing opening. The clamping device is detached from the connection pipe and removed through the housing opening. Then, the upper valve part and the internal fittings are reattached to the housing.

Abstract: A method for recycling AgInCd control rod absorber bar material from a used control rod from a nuclear power plant includes sectioning AgInCd absorber bar from a used control rod into a first section and a second section, the first section having a higher radioactivity than the second section; and recycling the material of the second section of the AgInCd absorber bar.

Abstract: A method of evacuating hot gases produced in a current breaking operation by a high voltage circuit breaker (1) which comprises a metal outer tank (2) filled with insulating gas, a casing (3) having gas outlet ports (30) and arranged inside the metal outer tank (2), with which it is in communication via the said ports, characterized in that insulating gas (GI) is aspirated from inside the casing (3) in a direction parallel to the flow of the hot gases (GC) produced by the current breaking operation, so as to mix the gases inside the casing (3) before they are evacuated, through the said gas outlet ports (30) of the casing, into the interior of the metal outer tank (2). The invention also relates to an associated high voltage circuit breaker, which includes means (5) for aspirating insulating gas from the interior of the casing (3), in a direction parallel to the hot gas stream.

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.