Abstract: Removable and lockable guide ring in an orifice passing through a plate and its use for a guide tube of a nuclear reactor. The guide ring comprises a tubular body (25), one part (25a) of which is introduced into the orifice (22) in the plate (20). A second part (25b) of the tubular body (25) comes up against the plate (20), and claws (40) having the form of being levers, for attaching the ring (21) to the edges of the orifice (22), are mounted freely in the tubular body (25). A spring (45) makes it possible to return the claws (40) into the attachment position. The invention applies particularly to a guide tube of a pressurized-water nuclear reactor.

Abstract: A device and process for fixing two parts with a captive screw (5) engaged in a threaded hole (3) machined in at least one of the two parts (1,2). The screw (5) comprises over its whole length a bore (6) communicating with at least one radially directed hole (10) opening out on the outer side surface of the screw (5) in its threaded part (5a) and enclosing a component (11) movable in the hole (10). A maneuvering rod (14) is engaged in the bore (6) for locking the screw (5) in place in the threaded hole (3), by placing a part of the rod with larger diameter to coincide with the component (11) which then crushes the threading of the part (3a) of the hole (3). The rod (14) is crimped over the screw (5) by virtue of strips (18). The disclosure applies in particular to the assembly of two walls of a partitioning of the core of a pressurized water nuclear reactor.

Abstract: The invention concerns a method and apparatus for eliminating leakage spaces between the partitions (1) surrounding the core of a pressurized water nuclear reactor, after it is brought into operation.Operations are carried out under water, during shutdown of the reactor. The defective joins (12) between the partitions (1) are identified. For each join, the partitions (1) are pierced, the hole inside a partition (1) is screw-threaded, the swarf is recovered, a screw with diametrical expansion is introduced and screwed into the hole and the screw is expanded by displacement of a rod in the longitudinal direction of the screw. Moving location, the operations are repeated for each defective join (12). The apparatus comprises a case (25) containing a drum (36) bearing tools for boring (54-65), screw-threading, and screwing, a cleaning tube and a punch for locking the screw.The invention is applicable to work on pressurized water nuclear reactors, after they have been brought into operation.

Abstract: A method and apparatus for eliminating leakage spaces between the partitions (1) surrounding the core of a pressurized water nuclear reactor, after it is brought into operation. Operations are carried out under water, during shutdown of the reactor. The defective joins (12) between the partitions (1) are identified. For each join, the partitions (1) are pierced, the hole inside a partition (1) is screw-threaded, the swarf is recovered, a screw with diametrical expansion is introduced and screwed into the hole and the screw is expanded by displacement of a rod in the longitudinal direction of the screw. Moving location, the operations are repeated for each defective join (12). The apparatus comprises a case (25) containing a drum (36) bearing tools for boring (54-65), screw-threading, and screwing, a cleaning tube and a punch for locking the screw.

Abstract: The invention relates to a temporary sealing obturation panel, inside a vessel accessible only through a manhole, of a passage provided on its periphery with a support collar. It is constituted by: panels articulated by flexible fluid-tight hinges, bordered by lines of latching pins, stiffeners comprising lines of holes conjugate with the lines of pins, a frame in at least two articulated parts, with means for gripping the ends of the panels and the stiffeners against the support collar. The invention is applicable to the closing of primary circuit ducts opening into the water box of a steam generator of a pressurized water nuclear boiler.

Abstract: The subject of the invention is a device for checking the disconnexion of the actuating rods of the control clusters before the removal of the internal equipment of a nuclear reactor, comprising, within a pit (10) forming a cooling pond, a vessel (1) closed by a removable cover and containing the core and a set of control clusters fitted slidably in the upper internal equipment forming a guide structure above the core, each cluster being fixed to the lower part (32) of an actuating rod (3) capable of being detached from the corresponding cluster, after opening the cover, by means of a disconnecting tool suspended from a charging crane (2) transportable above the cooling pond (10).

Abstract: A positioning and removal device for a checking means or a tool in a receiver installation, in a medium inaccessible to an operator. The device comprises a flexible guide track fixed to the receiver installation, a carriage movable over the track including a drive motor and a gear wheel, a loading sleeve fast to the carriage closed by a part and including a cam and a groove, a tool support unit provided with catches and an arrangement for hooking the support unit on a complementary arrangement borne by the installation. The forward movement of the carriage permits the opening of the hooking arrangement and hooking of the support unit onto the sleeve at the level of the groove by the catches, when the part is in out-of-service position. When the part is in service position on the sleeve, the forward movement of the carriage permits the transportation and hooking of the support unit of the tool to the receiver installation.

Abstract: A fixing device for detachably fixing a heating element to a sleeve welded to the body of the pressurizer of a nuclear reactor comprises an assembly of members with a symmetry of revolution, the axes of the members being coaxial with the heating element. The members comprise a gasket-carrying collar made integral with the heating rod and which bears on the outer face of a shoulder on the sleeve, a two-part ring which bears on the inner face of the shoulder on the sleeve, a screw-threaded nut and a screw-threaded tubular collar which are threaded together and bear respectively on the collar and the ring. The nut is provided with an opening for water leaking from the pressurizer and a zone of reduced thickness along which the nut can be cut in the event of seizure of the nut and tubular collar.

Abstract: The invention relates to a temporary sealing obturation panel, inside a vessel accessible only through a manhole, of a passage provided on its periphery with a support collar. It is constituted by: panels articulated by flexible fluid-tight hinges, bordered by lines of latching pins, stiffeners comprising lines of holes conjugate with the lines of pins, a frame in at least two articulated parts, with means for gripping the ends of the panels and the stiffeners against the support collar. The invention is applicable to the closing of primary circuit ducts opening into the water box of a steam generator of a pressurized water nuclear boiler.