Abstract: A servomotor includes a motor unit generating movement of a mechanical component, a position-detecting unit detecting the position of the mechanical component, and a control unit manually controlling the mechanical component. The manual control unit is inside a main enclosure, the manual control unit is actuated by an actuator located outside the main enclosure, and the main enclosure is connected to the motor unit and to the position-detecting unit, The position-detecting unit and the motor unit are located inside first and second enclosures that are distinct from the main enclosure and are removably connected to the main enclosure. The manual control unit can be actuated when the first and second enclosures are separated from the main enclosure.

Abstract: A method for assessing sealing of a housing of a servomotor. The method includes lowering the pressure inside the housing, from an initial pressure to a set pressure, by fluid suction through an opening in the housing, the opening being normally sealed by a plug. When the pressure inside the housing is equal to the set pressure, pressure variation inside the housing, for a predetermined time interval, is determined. The fluid suction prevents any fluid exchange with the housing in a direction opposite a fluid suction direction. The sealing of the housing of the servomotor is assessed based on the pressure variation determined.

Abstract: A device for connecting a servomotor to at least one electrical cable includes an external housing with at least one cable input, blocked by the cable in operation, and an opening closed by an electrical connection element and forming an interface with the servomotor. The electrical connection element includes a wall of an insulating material and elongate electrical contacts that extend through the wall in a direction substantially orthogonal to the wall, each electrical contact including an inner end inside the device for connection to an electrical cable, and outer end outside the device for being connecting to a corresponding electrical contact of the servomotor. The external housing includes an opening for draining fluid from inside the device in the operational configuration device, and the wall of the electrical connection element extends along a portion of the inner end of the electrical contacts.

Abstract: A servomotor includes a motor unit generating movement of a mechanical component, a position-detecting unit detecting the position of the mechanical component, and a control unit manually controlling the mechanical component. The manual control unit is inside a main enclosure, the manual control unit is actuated by an actuator located outside the main enclosure, and the main enclosure is connected to the motor unit and to the position-detecting unit, The position-detecting unit and the motor unit are located inside first and second enclosures that are distinct from the main enclosure and are removably connected to the main enclosure. The manual control unit can be actuated when the first and second enclosures are separated from the main enclosure.

Abstract: A method for assessing sealing of a housing of a servomotor. The method includes lowering the pressure inside the housing, from an initial pressure to a set pressure, by fluid suction through an opening in the housing, the opening being normally sealed by a plug. When the pressure inside the housing is equal to the set pressure, pressure variation inside the housing, for a predetermined time interval, is determined. The fluid suction prevents any fluid exchange with the housing in a direction opposite a fluid suction direction. The sealing of the housing of the servomotor is assessed based on the pressure variation determined.

Abstract: A device for connecting a servomotor to at least one electrical cable includes an external housing with at least one cable input, blocked by the cable in operation, and an opening closed by an electrical connection element and forming an interface with the servomotor. The electrical connection element includes a wall of an insulating material and elongate electrical contacts that extend through the wall in a direction substantially orthogonal to the wall, each electrical contact including an inner end inside the device for connection to an electrical cable, and outer end outside the device for being connecting to a corresponding electrical contact of the servomotor. The external housing includes an opening for draining fluid from inside the device in the operational configuration device, and the wall of the electrical connection element extends along a portion of the inner end of the electrical contacts.

Abstract: A device for the detachable fixing of an internal structure to a circular wall of a pipe or container.The device comprises one or more deformable annular members having blocks regularly distributed over its periphery. The application of radial forces between the blocks reduces the diameter level therewith and makes it possible to fit and remove the device.Application more particularly to the fixing of internal structures in the primary circuit of pressurized water reactors.

Abstract: The present invention relates to a nuclear boiler comprising a vessel whose top is closed by a dismountable cover, a cage bearing the core of the reactor and separating the vessel into an inner hot zone and an outer cold zone, at least one steam generator disposed outside the vessel and comprising a tight enclosure, a tube plate, separating the enclosure into a primary part, or water box, and a secondary part, and bearing U-shaped tubes whose ends open into two concentric zones of the water box separated by an internal structure, at least one hot connecting pipe and one cold connecting pipe respectively connecting the hot zone and the cold zone of the vessel to each of the concentric zones of the water box, wherein the tube plate, the tubes and the secondary part of the enclosure of the steam generator define a sub-assembly dismountable from the primary part of the enclosure, the hot connecting pipe being dismountably mounted between the cage and the internal structure of the water box, this strucutre itself

Abstract: Refuelling of a nuclear reactor and especially a PWR is carried out in the steps which consist in removing and storing the reactor closure head, in moving the control rods from a bottom position to the top position and securing the rods to the upper internal structure, in removing and storing the assembly constituted by the upper internal structure and the control rods, in replacing the spent fuel and in re-positioning the upper internal structure and the closure head.

Abstract: A device for guiding control rods of the absorber-pin cluster type and placed above the reactor core comprises a rigid top plate applied against the reactor vessel and provided with openings joined to long vertical tubes in which the control rod assembly is slidably mounted, an intermediate plate below coolant outlets for the sliding displacement of each absorber pin through corresponding apertures in said plate, and short connecting tubes which preferably provide a mechanical connection between the intermediate plate and a bottom plate and serve to guide the absorber pins, or alternatively short connecting tubes which guide the absorber pins and support members rigidly connected between the plates.

Abstract: Two cylindrical shells having different diameters and covered with a metallic heat-insulation are disposed respectively within the lower and upper portions of a pressure vessel, the upper shell being closed by a lid. A chamber filled with fluid in liquid phase up to the liquid-vapor interface and with gas above said level is formed by the shells between the vaporizable fluid and the internal vessel wall, a cold liquid seal being formed by the overlapping portion of the shells. Radial expansion of the shells is permitted by supporting means at the level of at least three through-passages and is absorbed by leak-tight means placed opposite to the through-passages.

Abstract: Closure elements uniformly spaced at the periphery of a concrete plug are each applied at one end against the top face of the plug and at the other end against the corbel of a prestressed concrete pressure vessel. Each closure element is constituted by a hydraulic jack whose closed extremity is coupled to a first articulated bearing shoe. Adjustable mechanical means within the jack body maintain this latter in contact with an annular shoulder of the jack piston in all relative positions, the emergent extremity of the piston being coupled to a second articulated bearing shoe.

Abstract: The invention relates to a device for inspecting at a distance walls which are difficult of access such as metal walls forming a nuclear reactor vessel. The device comprises a detector secured to a slide movable along guide rails attached to a frame. Probes bearing on the metal walls are secured to a plate on the frame, each probe transmitting a signal proportional to the distance between the guide rails and the place where the probe bears on the part of the wall to be checked. The device includes two motors secured to a second frame and which are controlled by electrical signals from the probes. Each motor actuates a pinion engaging the racks secured by pivots to the first frame and the two ends of the guide rails. A potentiometric monitoring device stops the motors when the signals proportional to the distance between the wall and guide rails as measured by the probes are equal to one another and to a controlled value. The detector preferably comprises an assembly of transducers and ultrasonic receivers.