Abstract: This method comprises the steps of: transmitting a beam of light onto a surface (17) of an element (1) comprising a fissile material, passing the beam of light reflected by the surface into a polarisation analyser (27) having a modifiable analysis direction, transmitting the beam from the polarisation analyser (27) to a device (31) for acquiring digital images, acquiring at least one digital image (31) of the surface (17) of the element (1) and processing the digital image acquired in order to measure the anisotropy. Use, for example, in controlling particles of nuclear fuel for an HTR/VHTR type reactor.

Abstract: An electric switch including a stationary contact that is annular. The switch comprises a gastight enclosure, a conductor bar of axis (D), a stationary contact presenting a contact zone of substantially annular shape, a switch element, e.g. on the conductor bar, that is movable in the axial direction of the axis (D) between a first position in which it penetrates in part into the stationary contact to establish electrical contact between the conductor bar and the stationary contact, and a second position in which it interrupts said contact. The stationary contact, which is in the form of a ring that is circular or elongate, such as elliptical, surrounds the conductor bar, at least in part.

Abstract: The present invention relates to the use of lithium salts and/or magnesium salts for the precipitation of aluminum oxides present in aqueous media.

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.

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: An antiseismic support pad having a base for supporting and holding the pad on a support surface, at least one spherical rolling element mounted to rotate freely about a center of rotation in a bearing secured to the support base, and a support plate resting on the spherical rolling element via a concave bearing surface, the pad being characterized by the fact that the support base comprises a soleplate secured to at least one bearing, configured to rest freely on the support surface and to hold the pad in place on the support surface without a fastener, and that the support pad includes an arrangement configured to suspend the support base from the support plate and move the base resiliently in radial directions about a support plate axis that is substantially perpendicular to the soleplate, the arrangement connected firstly to the support plate and secondly to the support base comprising the soleplate and the bearing.

Abstract: A method of repairing a vessel bottom head penetration of a nuclear reactor is presented, said penetration comprising a tube fastened to the internal wall of the vessel bottom head by an internal weld bead and emerging outside the vessel bottom head, forming a groove. The method consists inter alia in preparing a mock-up representative of the vessel bottom head penetration to be repaired and in depositing this mock-up on site in an irradiation-free zone, in fastening two half-inserts to this mock-up in the groove, each half-insert having a profile corresponding to the half-profile of the groove, in forming, again on this mock-up, automatically and by remote control, a weld bead in the groove, in carrying out a dimensional check and, after validation of this weld bead, in carrying out the steps of fastening the two half-inserts and forming a weld bead automatically, directly in the groove of the vessel bottom head penetration to be repaired.

Abstract: A nuclear fuel assembly bottom nozzle, of the type including a perforated plate to allow water to pass through it, the nozzle having lateral faces, and at least one anti-debris element positioned on a lateral face to block out debris likely to infiltrate between the bottom nozzle and another adjacent bottom nozzle, characterized in that, in the free state, the or each anti-debris element permanently projects from the lateral face on which it is positioned, the or each anti-debris element being elastically deformable so as to retract towards the lateral face in the event of a force being exerted on the anti-debris element towards the lateral face.

Abstract: The present invention relates to the use of lithium salts and/or magnesium salts for the precipitation of aluminum oxides present in aqueous media.

Abstract: A current-interrupting chamber is filled with a dielectric fluid and includes a moving assembly. The moving assembly is mounted to move axially between a position at the start of a circuit-breaker opening operation and a position at the end of a circuit-breaker opening operation. The moving assembly has a first compression chamber whose volume decreases between the start position and a position in which the first chamber is open; a first arcing contact designed to co-operate with a second arcing contact; and a second compression chamber communicating with the first compression chamber. The volume of the second compression chamber decreases between the start position and the end position. The second compression chamber is designed to inject fluid into the first compression chamber, between the open position and the end position, when the pressure in the first chamber is lower than the pressure in the second chamber.

Abstract: An assembly of the type having a water channel extending along a longitudinal axis and having an upper section of larger cross-section area than a lower section and at least one fuel rod receiving groove extending longitudinally on the outer surface of the lower section, fuel rods extending longitudinally and disposed around the water channel and fixing members for fixing at least one fuel rod to the water channel in the at least one groove below the upper section. According to one aspect of the invention, the at least one groove extends along the upper section such that a fuel rod received in fixing members is longitudinally extractable or insertable from the upper end side of the fuel assembly.

Abstract: Methods and systems for generating steam using solar energy are provided here. The methods and systems can be used to generate steam of a desired quality, e.g. about 70%, or superheated steam. Some methods for producing steam of a desired quality comprise flowing water into an inlet of receiver in a linear Fresnel reflector system, wherein the receiver comprises multiple parallel tubes ti connected in parallel, and i=1,k, and irradiating each tube ti along its respective length Li with solar radiation so that solar radiation absorbed at each tube generates thermal input along its length and so that water begins to boil in at least one of the tubes at a point ?i along its length. The methods comprise using one or more temperatures Ti in an economizer region of a tube ti or one or more changes in length of the tubes as input to a controller that controls mass flow of water into each of the multiple tubes, thereby controlling quality of steam exiting the receiver.

Abstract: A reflector element carrier structure is disclosed for use in a solar energy reflector system. The structure comprises a reflector element (11), a corrugated platform (12) which carries the reflector element and a skeletal frame structure (13) which supports the platform. The frame structure comprises hoop-like end members (14) that are supported by rollers (18) and the rollers accommodate turning of the carrier structure about an axis of rotation that lies substantially coincident with a longitudinal axis of the reflector element (11). The combination of the corrugated platform (12), the frame structure (13) and the hoop-like end members (14) of the frame structure provide the carrier structure with a torsional stability that permits the application of turning drive from one end of the structure.

Abstract: A method for removing corrosion products from a system, the method including: adjusting the system temperature to between 115° F. to 212° F.; injecting a cleaning dissolution solvent into the system; injecting a gas into the system after the system is filled with the cleaning dissolution solvent; the gas mixing with the solvent in the system; draining the solvent from the system after a predetermined period of time of dissolution; injecting a passivation composition into the system; injecting a gas into the system, the gas mixing the passivation composition; draining the system of the composition after a predetermined period of time of passivation; rinsing the system with a low volume solution; and rinsing the system at with a full volume solution.

Abstract: A method for the surface tribological decontamination of nuclear fuel rods automates surface wiping by one or more bands of fabric. The band is distant from the axis of the rod, the rod is placed facing the band, and then the band is tensioned around the surface of the rod and moved. The rod may be immobile, moved in pure translation along its axis or with a wide-step helical movement. Preferably, the decontamination is carried by two bands simultaneously, so as to cover the total surface in one pass of the rod.

Abstract: A method including placing around the shoulder of the lid a ring-shaped gasket formed by a metal strip maintained on the vertical wall of the shoulder by self-maintaining members firmly attached to the strip, placing the lid bearing the ring-shaped gasket above the vessel by positioning it at a determined height, carrying out a cleanliness inspection of the gasket plane, lowering and laying the lid on the vessel so that the end side edges of the strip will come into contact with a horizontal wall of the lid and of the vessel flange respectively and attaching this lid on the vessel.

Abstract: An assembly for a grounding disconnector, a grounding disconnector including the assembly and a method of manufacturing a grounding disconnector are described. The assembly includes a stationary grounding contact (12), a phase contact (14) suitable for being connected electrically to a busbar (8), moving connection means (16) suitable for putting the stationary grounding contact (12) and the phase contact (14) into electrical contact with each other, the stationary grounding contact (12), the phase contact (14) and the moving connection means (16) being mounted on a mounting plate (6).

Abstract: The subject of the present invention is: a casing internal part (1) suitable for the dry intermediate storage of at least one irradiated fuel element. Said casing internal part (1) has a tiered structure which comprises at least two superposed modules (M1, M2, M3, M4), each of said modules (M1, M2, M3, M4), made of a material that is a good conductor of heat, with compartment(s) (2a, 2b) for accommodating said fuel element(s) in the central part and with at least one hollowed-out peripheral heat sink (3a, 3b), being arranged on a support plate (4) that is perforated to allow said fuel element(s) through; the perforated support plates (4) of said structure being positioned and assembled by means of a retaining system (5?+5+5?), with a clearance (J) left between the top of the module of one tier (Mi) and the perforated support plate (4) of the tier (Mi+1) immediately above; a temporary storage casing (10) equipped with such a casing internal part (1); and the corresponding temporary storage method.

Abstract: A dry conversion reactor for converting uranium hexafluoride to uranium dioxide, the dry conversion reactor including a gas-phase reaction segment and a fluidized bed segment, wherein at least one of the gas-phase reaction segment and the fluidized bed segment is a replaceable segment. A method for operating a dry conversion reactor utilizing a uranium hexafluoride to uranium dioxide conversion process, the method including replacing at least one conversion reactor segment.

Abstract: Checking apparatus for checking operation of a densimeter for medium-voltage or high-voltage equipment having metal casing (4) that is filled with a dielectric gas under pressure; the apparatus comprises a closed chamber (8) suitable for being put into communication with an internal space (5) of the casing (4), and isolation means (10) for isolating the chamber (8) in gastight manner from the internal space (5), in which apparatus said closed chamber (8) has a volume that can be caused to vary, and in which apparatus the densimeter is suitable for detecting at least one pressure threshold in said chamber.