FR2585501A1 - Automatic devices for maintenance or repair of steam generators of nuclear reactors - Google Patents

Abstract

A mechanical unit for remotely controlled operations on the exchanger tubes of steam generators of pressurised water nuclear power stations. This device comprises: - a remote-control locating manipulator arm (or positioner) 901 in the water box (bowl) parallel to the tube plate; - a lift 902 mounted on the positioner, serving as a slide for a rack 903 responsible for the positioning 904 on the tube plate or else on a stationary delivery station 905; on this rack, a set of stationary 906 and mobile 907 clamps for the vertical introduction of the tools and/or sleeves 908 into the tubes; - a transfer (conveyor) 909 with a stationary loading station, a rail 912 with its trolley 910 with a clamp 911, a delivery station 905 in the bowl; - lastly, a manipulating robot 913 essentially intended for locating the sleeves on the tool placed on the trolley 910.

Description

INTERVENTION AUTOMATISMS FOR NUCLEAR REACTOR STEAM GENERATORS
The invention relates to a mechanical remote control assembly intended for multiple interventions (checks, repairs, etc.) on the exchanger tubes of steam generators (steam generators) of pressurized water nuclear power plants.

The most important of these interventions concerns the cracks which appear on the exchanger tubes, in particular in an area corresponding to the end of the expansion of the tubes in the tube plate and / or to the thickness of a deposit of solidified sludge in the circuit. secondary.

The repair principle commonly adopted consists in introducing a cuff into the offending tube and in assembling this cuff in a leaktight manner by mechanical and / or metallurgical processes, covering the deteriorated area.

The viability of this device requires that it be applicable to a large number of tubes, and that each type of operation can be carried out at an industrial rate compatible with the times allocated to the periodic shutdowns of nuclear power plants (unit shutdowns).

This device is characterized in that it is composed of a series of automata installed in and near the water boots, complementary to each other, namely: - a presentation remote manipulator (or positioner) in the water boot ( bowl) parallel to the tubular plate - and sweeping it in its entirety, - a lifting device mounted on the preceding positioner, and responsible for vertically introducing tools and / or sleeves into the tubular plate and into the exchanger tubes, - a server automaton of the previous device for the introduction into the bowl of tools and / or cuffs, - finally a handling robot, essentially intended for the presentation of cuffs on the server automaton.

The positioner and the elevator are assembled inside the water boot, manually and simply by an operator operating in the contaminated bowl, in a period of time compatible with its safety.

The server and its charger are installed outside the GV, near the manhole accessing the water box.

In the following, the invention is explained in more detail using drawings representing only one embodiment.

Figure 1 locates the water boots of the Steam Generators (GV) of pressurized water reactors.

The GV water boot is a half sphere formed by two chambers 901 separated by a vertical plate 904; these chambers are overhung by the tubular plate (PT) 902 from which leave and where terminate the exchanger tubes 903 mounted in a pin. Each chamber (bowl) has two openings: the access manhole 905 with a diameter of 400mm. approximately, and the tubing 906 of the primary circuit.

Figure 2 as a whole describes the configuration of the device in and near a water boot.

The positioner 910 consists of an arm-beam rolling on a rail fixed on the periphery of the tubular plate and supported by a fixed base free to rotate against the partition plate of the bowl, as described in an earlier patent (Application N084 01588 February 2, 1984: Remote manipulator for steam generators in nuclear power plants).

This beam-arm carries a self-propelled carriage on which the lifting device is mounted.

The elevator is characterized in particular in that it is provided with two indexing heads: one intended for fine centering on the tube plate, the other for alignment with the transfer machine.

For this purpose the elevator has a base 911 interface with the carriage, on which slides vertically a frame 912 provided with two centering indexing systems): - The upper head 915 for centering, controlled in rotation, is used for precise alignment of the elevator on the tube to be treated by the engagement of two pins in the tube plate on either side of this tube. I1 thus takes reference according to the network of tubes, in the tube plate.

- The lower finger 916, fixed under the chassis, ensuring docking and fine positioning on the delivery station of the transfer machine.

The lifting device proper, which carries the chassis 912, consists in the high position of a fixed guide member 914, in the low position of a clamp 913 also fixed, and of a clamp 917 movable vertically between the two preceding elements .

The transfer of load between the two clamps allows the introduction into the tubes of tools and / or cuffs, by successive lengths of the value of the stroke of the movable clamp 917.

The transfer device (or server) 920 is positioned outside the GV.

 I1 consists of a fixed loading station 921, a conveyor rail 922, and a fixed delivery station 923 in the bowl of the GV.

Between these two stations circulates on the rail a transfer carriage 924 equipped with a clamp 925 for gripping the tools.

In the case of sleeving, the tool for positioning the cuff in the tubes also serves to transfer the latter. At the fixed loading station 921, this tool 926 is gripped by the clamp 925 of the transfer carriage and receives a cuff 927 threaded onto its rigid head by the handling robot 930.

The role of this loading robot 930 is limited to presenting a tool to the transfer cart 924, or even cuffs on a tool head, for their transfer to the elevator in the bowl of the GV.

Figures 3, 4 and 5 show schematically the kinematics of setting up a cuff.

Figures 3a, b represent the loading phase of the elevator: - The cuff 927 at the end of the positioning tool 926 is brought into the bowl by the transfer carriage 924, while the positioner manipulator 910 came to present the lift for indexing its chassis 912 on the delivery station 923.

- The rail 922 ending in a vertical straight section, the stroke of the transfer carriage 924 engages the cuff and its tool - in the fixed clamp 913, the movable clamp 917 in the low position, the fixed guide member 914 and the head centering 915.

- The mobile clamp 917 takes up the tool 926, which is released by the clamp 925 of the transfer carriage, and the chassis 912 uncouples from the delivery station.

FIGS. 4a, b represent the operating principle of the elevator for the introduction of the cuffs into the tubular plate: - The frame 912 is brought into contact on the tubular plate for engagement of the pins of the centering head 915 on the one hand and other side of the tube to be sleeved, then the movable clamp 917 performs its vertical engagement stroke.

- When the movable clamp is in the high position on the chassis, the fixed clamp 913 in turn grasps the body of the tool 926 to allow the loose movable clamp to descend.

- The mobile gripper then takes up the tool for a new engagement stroke, until the cuff is positioned at the desired height.

Figures 5a, b represent the return of the tool to the loading station outside the GV to receive a new cuff: - The remote manipulator 910 comes to present the elevator again for its indexing at the delivery station where the clamp 925 of the transfer carriage comes to take up tool 926 in a reverse sequence to the first.

- The transfer cart is brought back to the loading station 921 to receive a new cuff served by the handling robot 930.

Claims (1)

CLAIMS: Claim 1: Automated mechanical remote control assembly in the water boots of steam generators, characterized in that it comprises: a) a positioner (or presentation manipulator) bringing the tools (and / or the sleeves) facing the holes in the plate the tube plate, b) a lifting device introducing the tools and / or the cuffs into the tubes, transported by the positioner, c) a transfer (or conveyor) system introducing the tools and / or cuffs to the fixed station, inside of the water boot. Claim 2: Device for conveying tools and sleeves according to claim 1, characterized by: a) a fixed position for loading the sleeves outside the GV, b) a fixed position for delivering the sleeves inside the water boot from the GV, c) a connecting rail on which a transfer carriage circulates. Claim 3: Device according to claim 2, wherein the delivery station is located below the lowest level of the lifting device. Claim 4: Device according to 2 where the cuffs are presented on the transfer cart by a handling robot Claim 5: Lifting device according to claims 1 and 3, characterized in that it comprises two precision indexing devices: a) one working in relation to the tube plate, b) the other in relation to the delivery station of the transfer device. It includes a base 911 fixed on the positioner, base on which slides vertically a chassis 912 provided with two indexing heads: an upper head 915 carrying pins coming to engage in the tubes of the plate, tubular, and a lower finger 916 ensuring fine positioning on the delivery station. Claim 6: Lifting device according to claim 5 characterized in that the chassis 912 carries in the haunted position a fixed guide member 914 through which the sleeves and the tools pass, in the low position a clamp 913 also fixed, and a clamp 917 movable moving vertically between the two previous elements. Claim 7: Automatic cuff positioning device according to claim 6, characterized in that the cuff 927 is loaded on a tool 926 which is loaded on the transfer carriage 924; that the tool 926 during the introduction is held by the clamp 925 of the carriage, that it is gripped at the delivery station by the movable clamp 9L7 of the elevator, that the chassis is indexed on the tubular plate at the 'chosen place, that by alternating maneuvers between fixed clamp 913 and movable clamp 917, the tool with its cuff is introduced into the tubular plate at the desired height. Claim 8: Automatic cuff installation device according to claim 1, characterized in that the tool which immobilizes the cuff in the tube concerned, serves as a conveyor for the cuff. Also characterized in that: at each operation, this tool is in turn secured to the transfer carriage, then secured to the elevator; this tool returns to the delivery station where it is picked up by the transfer cart, to descend to the non-GV loading station where it receives a new cuff.