Abstract: An assembly for acting on the outer surface of a tube, and corresponding method are provided. The assembly includes a carrier; at least one inspection or maintenance tool; the carrier includes at least one rolling body; an actuator. The carrier further includes a device for connecting the carrier to the tube, arranged so that the tube absorbs at least 50% of the weight of the carrier and the tool.

Abstract: An assembly for acting on the outer surface of a tube, and corresponding method are provided. The assembly includes a carrier; at least one inspection or maintenance tool; the carrier includes at least one rolling body; an actuator. The carrier further includes a device for connecting the carrier to the tube, arranged so that the tube absorbs at least 50% of the weight of the carrier and the tool.

Abstract: The invention concerns a method for repairing guide rails (27) of an assembly (10) radially maintaining a core supporting plate (5), which consists in measuring the spacing between the spans of the lateral branches of the guide rail (27) to be repaired, cutting and removing at least one lateral branch of said guide rail (27) to be repaired, measuring the dimensions of said lateral branch and machining with identical dimensions at least one substitution lateral branch, mounting and fixing said substitution lateral branch and measuring the spacing between the spans of the lateral branches of the repaired guide rail.

Abstract: The invention concerns a method for repairing guide rails (27) of an assembly (10) radially maintaining a core supporting plate (5), which consists in measuring the spacing between the spans of the lateral branches of the guide rail (27) to be repaired, cutting and removing at least one lateral branch of said guide rail (27) to be repaired, measuring the dimensions of said lateral branch and machining with identical dimensions at least one substitution lateral branch, mounting and fixing said substitution lateral branch and measuring the spacing between the spans of the lateral branches of the repaired guide rail.

Abstract: A device for handling a guide tube assembly. The assembly has an upper tube and a lower tube in each of which there are fixed horizontal guide plates arranged such that they are spaced apart in an axial direction. The handling device itself includes a gripper having a tubular body and two opposing arms located at one end of the tubular body and moveable between a retracted position and a deployed position, the arms bearing against a lower surface of a contacted guide plate when in the deployed position. A control member is located at an opposite end of the tubular body for controlling the arms. The length of the tubular body of the gripper selected to be: a) greater than the distance between an upper end of the upper tube and a first guide plate of the lower tube; and b) less than the distance between the upper end of the upper tube and a third guide plate of the second tube.

Abstract: The invention relates to a method for handling a nuclear reactor upper internals guide tube (15), in which method a gripper (30) equipped, at a first end, with two opposed arms (32) that can be moved between a retracted position and a deployed position and, a second end, with a control member (37) for controlling the said arms is introduced into horizontal guide plates (24) of the upper tube (16) of the guide tube (15), the first end of the gripper (30) is placed under one (25A) of the two upper guide plates of the lower tube, the two arms are deployed, the two arms are applied under this guide plate and the gripper (30) is used to simultaneously raise the two tubes of the guide tube (15).

Abstract: The apparatus for positioning a fuel assembly (10) comprises, on a respective side of the core support plate (19) and the upper core plate (9) directed towards an endpiece (15, 14) of the fuel assembly (10) at least two projecting positioning pins (16, 22) adapted to engage in openings in the lower endpiece (15) or upper endpiece (14). Each of the positioning pins (16, 22) is fixed in a blind opening (24) comprising a threaded bore and a support surface perpendicular to the axis of the blind opening (24) and comprises a flange adapted to come into contact with the support surface when the positioning pin (16, 22) is screwed into the threaded bore. A gudgeon enables the positioning pin to be locked to secure it against unscrewing. The invention also relates to a process and apparatus for replacing damaged positioning pins on the core support plate (19) or on the upper core plate (9).

Abstract: The apparatus for positioning a fuel assembly (10) comprises, on a respective side of the core support plate (19) and the upper core plate (9) directed towards an endpiece (15, 14) of the fuel assembly (10) at least two projecting positioning pins (16, 22) adapted to engage in openings in the lower endpiece (15) or upper endpiece (14). Each of the positioning pins (16, 22) is fixed in a blind opening (24) comprising a threaded bore and a support surface perpendicular to the axis of the blind opening (24) and comprises a flange adapted to come into contact with the support surface when the positioning pin (16, 22) is screwed into the threaded bore. A gudgeon enables the positioning pin to be locked to secure it against unscrewing. The invention also relates to a process and apparatus for replacing damaged positioning pins on the core support plate (19) or on the upper core plate (9).

Abstract: The invention relates to a method for handling a nuclear reactor upper internals guide tube (15), in which method a gripper (30) equipped, at a first end, with two opposed arms (32) that can be moved between a retracted position and a deployed position and, a second end, with a control member (37) for controlling the said arms is introduced into horizontal guide plates (24) of the upper tube (16) of the guide tube (15), the first end of the gripper (30) is placed under one (25A) of the two upper guide plates of the lower tube, the two arms are deployed, the two arms are applied under this guide plate and the gripper (30) is used to simultaneously raise the two tubes of the guide tube (15). The invention also relates to a handling device for implementing this method.

Abstract: The apparatus for positioning a fuel assembly (10) comprises, on a respective side of the core support plate (19) and the upper core plate (9) directed towards an endpiece (15, 14) of the fuel assembly (10) at least two projecting positioning pins (16, 22) adapted to engage in openings in the lower endpiece (15) or upper endpiece (14). Each of the positioning pins (16, 22) is fixed in a blind opening (24) comprising a threaded bore and a support surface perpendicular to the axis of the blind opening (24) and comprises a flange adapted to come into contact with the support surface when the positioning pin (16, 22) is screwed into the threaded bore. A gudgeon enables the positioning pin to be locked to secure it against unscrewing. The invention also relates to a process and apparatus for replacing damaged positioning pins on the core support plate (19) or on the upper core plate (9).

Abstract: The apparatus for positioning a fuel assembly (10) comprises, on a respective side of the core support plate (19) and the upper core plate (9) directed towards an endpiece (15, 14) of the fuel assembly (10) at least two projecting positioning pins (16, 22) adapted to engage in openings in the lower endpiece (15) or upper endpiece (14). Each of the positioning pins (16, 22) is fixed in a blind opening (24) comprising a threaded bore and a support surface perpendicular to the axis of the blind opening (24) and comprises a flange adapted to come into contact with the support surface when the positioning pin (16, 22) is screwed into the threaded bore. A gudgeon enables the positioning pin to be locked to secure it against unscrewing. The invention also relates to a process and apparatus for replacing damaged positioning pins on the core support plate (19) or on the upper core plate (9).

Abstract: To repair the internal thread (2b) of a large diameter orifice, an added thread is screwed into the orifice in a form wound on a threaded part of the surface of a drum screwed into an internally threaded centering ring engaged in the entry part (2a) of the orifice (2). The thread is laid against the internal thread (2b) and fastened in place by installing a pin passing through the thread and engaged in the wall of the orifice (2). The process is used for repairing the internal threads of orifices (2) machined in the flange of a pressurized-water nuclear reactor vessel, allowing the vessel cover to be bolted down sealingly.

Abstract: The centering device comprises a centering plate (23) mounted on a carrier member (21) for rotation about an axis parallel to the axis of the steam generator tubes and carrying two radial expansion fastening grippers (39), and a drive (22, 27, 28) for orientation of the plate (23) about its axis. The fastening grippers (39) are disposed on the plate in relative positions corresponding to openings provided in the tube plate (18) for the passage of the tubes (13).

Abstract: The body (4) of the plug (3) is rebored in the direction of its end wall (6) and the clamp block (7) is drilled by an electric machining process, over a substantial part of the length of the plug. The wall of the plug body (4) is relieved of stress with the aid of a welding torch introduced into the bore made by electric machining, and a gripping tool is introduced into the bore in order to extract from the tube the plug body (4) which has been relieved of stress.