JP2014028373A - Shroud installation device and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shroud installation device for shortening a work construction period, by securing sound welding quality of an installation part.SOLUTION: An embodiment comprises: an inside traveling carriage 7a for traveling along an inside rail 5 installed along an inner periphery of a shroud 3; a welding device 7 mounted on an inside traveling carriage 7a and welding between a support cylinder 2 and a lower end groove part of the shroud 3; an outside traveling carriage 8a for traveling along an outside rail 6 installed along an outer periphery of the shroud 3; and a control part 16. A monitoring device 8 mounted on the outside traveling carriage 8a and monitoring a welding state by the welding device 7 and the control device 16, are provided with a movement control part for controlling a traveling speed of the inside traveling carriage 7a and the outside traveling carriage 8a so that the welding device 7 and the monitoring device 8 synchronously move and a welding control part for controlling a welding condition of the welding device 7 based on the welding state monitored by the monitoring device 8.

Description

  Embodiments described herein relate generally to a shroud installation apparatus and method for performing welding on a shroud installation portion that is narrow and difficult to access in a boiling water reactor.

  A boiling water reactor is a cylindrical structural member having a diameter of about 4 m and a thickness of about 50 mm (1.1 million kW) slightly smaller than a reactor pressure vessel called a shroud inside a reactor pressure vessel (RPV). Is stored. Various devices such as fuel and control rods are installed in the shroud.

  The existing shroud needs to be replaced with a new shroud for preventive maintenance and extension of the operation period. The welding operation for installing this new shroud is performed in a reactor pressure vessel. This welding operation is performed from the inside of the shroud by an automatic TIG welding (Tungsten Inert Gas welding) machine. The weld groove shape is a narrow groove on one side in order to reduce the welding amount. This one side narrow groove is difficult to control the welding conditions.

  On the other hand, the narrow part between the outer side of the shroud and the reactor pressure vessel is called an annulus part, and is a space that is difficult to access in which the diffuser and the sensing line of the jet pump are arranged. When repair work occurs at the time of welding and it is necessary to construct the repair work from the outside of the shroud, which is difficult to access, the welding worker cannot cope with it, which affects the work period.

  As a method for replacing the shroud, for example, there is a technique described in Patent Document 1. In this technique, a setup work and a welding method in installing a shroud are proposed, and the work procedure is simplified and the removal work after use is reduced.

  The technique described in Patent Document 2 also describes a setup operation and a welding method in the installation of the shroud, which shortens the installation process of the in-furnace structure and reduces the exposure of the operator. is there.

JP-A-8-297192 JP-A-8-105990

  By the way, in the techniques described in Patent Documents 1 and 2, in order to install a new shroud, a method for specifically controlling the welding conditions such as the bead width is proposed when welding is performed from the inside of the shroud by an automatic TIG welder. It has not been. Therefore, there is a possibility that sound welding quality cannot be maintained.

  Moreover, in the technique described in patent document 1 and 2, when the repair of a welding part is needed, the construction method is not proposed.

  Embodiments of the present invention have been made in view of such circumstances, and an object of the present invention is to provide a shroud installation device and method that ensure sound welding quality of the installation portion and shorten the work period. And

In order to achieve the above object, a shroud installation apparatus according to an embodiment of the present invention is a shroud installation apparatus that installs a new shroud on a support cylinder installed in a reactor pressure vessel by welding. An inner traveling carriage that travels along an inner rail installed along an inner periphery, and a welding device that is mounted on the inner traveling carriage and welds between the support cylinder and a lower end groove portion of the shroud;
An outer traveling cart that travels along an outer rail installed along the outer periphery of the shroud, a monitoring device that is mounted on the outer traveling cart and monitors a welding state by the welding device, the welding device, and the monitoring device And a welding control for controlling the welding conditions of the welding apparatus based on the welding state monitored by the monitoring device. And a section.

  A shroud installation method according to an embodiment of the present invention is a shroud installation method in which a new shroud is installed on a support cylinder installed in a reactor pressure vessel by welding, and is installed along the inner circumference of the shroud. A welding step of moving along an inner rail to weld between the support cylinder and a lower end groove portion of the shroud by a welding device; and the welding device along an outer rail installed along an outer periphery of the shroud And a monitoring step of monitoring a welding state by the welding device by a monitoring device, and a welding control for controlling a welding condition of the welding device based on the welding state monitored by the monitoring device after the monitoring step And a step.

  According to the embodiment of the present invention, it is possible to ensure sound welding quality and shorten the construction period.

It is an elevational sectional view showing a shroud and its peripheral devices installed by applying the first embodiment of the present invention. It is an expanded vertical sectional view which shows the welding part of the shroud of FIG. FIG. 3 is an elevational view seen from the direction of arrow III in FIG. 2. It is a plane sectional view which shows the welding state of the shroud of FIG. It is a flowchart which shows the welding method using the welding apparatus of FIG. It is a front view which shows the repair apparatus etc. which are installed in the shroud outer peripheral side in 2nd Embodiment of this invention.

  Hereinafter, embodiments of a shroud installation device according to the present invention will be described with reference to the drawings. In the following embodiment, a case where a new shroud is installed after an existing shroud is removed will be described.

(First embodiment)
FIG. 1 is an elevational sectional view showing a shroud and its peripheral devices installed by applying the first embodiment of the present invention. FIG. 2 is an enlarged vertical sectional view showing a welded portion of the shroud of FIG. FIG. 3 is an elevation view seen from the direction of arrow III in FIG. 4 is a cross-sectional plan view showing a welded state of the shroud of FIG. FIG. 5 is a flowchart showing a welding method using the welding apparatus of FIG.

  As shown in FIG. 1, a cylindrical support cylinder 2 is installed in the reactor pressure vessel 1. A new cylindrical shroud 3 is installed on the upper end of the support cylinder 2 by welding. A welded portion 4 shown in FIGS. 2 and 3 is formed between the upper end of the support cylinder 2 and the lower end groove portion of the shroud 3. The welded portion 4 shown in FIGS. 2 and 3 is in a state at the time of initial layer welding, and is built up by a plurality of welding times.

  As shown in FIG. 1, the shroud 3 is provided with an inner rail 5 on the inner peripheral side. On the outer peripheral side of the shroud 3, an outer rail 6 is formed integrally with the outer peripheral surface of the shroud 3 at substantially the same height as the inner rail 5. The outer rail 6 may be newly installed on the outer peripheral side of the shroud 3.

  As shown in FIG. 4, an inner traveling carriage 7 a is installed on the inner rail 5 so as to be able to travel in the circumferential direction. Further, an outer traveling carriage 8a is installed on the outer rail 6 so as to be able to travel in the circumferential direction. An automatic TIG welding device 7 that can be operated remotely is mounted on the inner traveling carriage 7a. A CCD camera 8 as a monitoring device is mounted on the outer traveling carriage 8a. Since the outer traveling carriage 8a and the CCD camera 8 have a width within 50 mm, they can travel on the outer rail 6 even in a narrow place.

  A control panel 15 is installed on an operation floor (not shown). The control panel 15 includes a control device 16, an input device 19, and a display device 20. The control device 16 has a CPU 17 and a database 18 such as a hard disk. In addition to driving or stopping the inner traveling carriage 7a and the outer traveling carriage 8a, the input device 19 sends an input signal for driving or stopping the automatic TIG welding apparatus 7 to each part. The control device 16 functionally includes a movement control unit and a welding control unit.

  The control device 16 controls the traveling speed so that the inner traveling carriage 7a and the outer traveling carriage 8a move in synchronization. That is, the control device 16 has a function as a movement control unit, and controls the moving speed so that the automatic TIG welding device 7 and the CCD camera 8 move in synchronization.

  The control device 16 has a function as a welding control unit, and controls the welding conditions of the automatic TIG welding device 7 based on the welding state monitored by the CCD camera 8. Specifically, the welding state photographed by the CCD camera 8 includes the bead width, groove width, and melted area of the first layer welded portion. This welding state is displayed on the display device 20. The welding conditions of the automatic TIG welding apparatus 7 include a welding current, a welding voltage, a welding speed, a wire supply speed, and the like.

  In the present embodiment, the welding current, welding voltage, and welding conditions of the automatic TIG welding apparatus 7 are calculated from the bead width, groove width, and melted area of the backside weld of the first layer welded portion photographed by the CCD camera 8. The welding speed and the wire supply speed are recorded in the database 18 in advance.

  That is, in this embodiment, the optimum welding current, welding voltage, welding speed, wire supply speed, etc. from the welding state such as the bead width, groove width, and melted area of the back layer of the first layer welded portion in advance. Welding conditions are stored in a database, appropriate welding conditions are selected from the above welding conditions, and the welding conditions are fed back to the automatic TIG welding apparatus 7 that moves in the circumferential direction on the inner rail 5 attached to the inside of the shroud 3. I am doing so.

  Next, the operation of this embodiment will be described.

  For preventive maintenance of the reactor and extension of the operation period, fuel (not shown) is taken out of the reactor pressure vessel 1 when the reactor operation is stopped, and the existing shroud is removed. Next, the top surface of the support cylinder 2 is shaped, and a new shroud 3 is suspended and centered.

  Then, the automatic TIG welding apparatus 7 welds between the upper end of the support cylinder 2 and the lower end groove part of the shroud 3 in step S1 of FIG.

  Next, the welding state of the automatic TIG welding apparatus 7 is monitored at step S2. Specifically, the CCD camera 8 is moved in synchronization with the automatic TIG welding apparatus 7, and the bead width, groove width, and melting of the back wave of the first layer welded portion welded by the automatic TIG welding apparatus 7 are melted. The area is monitored by the CCD camera 8.

  Furthermore, welding control is performed in step S3. Specifically, the control device 16 determines the welding current, welding voltage, and welding of the automatic TIG welding device 7 based on the bead width, groove width, and melted area of the welded first layer weld. Control speed and wire feed rate.

  As described above, according to the present embodiment, the automatic TIG welding apparatus 7 and the CCD camera 8 are moved synchronously, and the welding conditions of the automatic TIG welding apparatus 7 are controlled based on the welding state monitored by the CCD camera 8. Since it is possible to ensure the sound welding quality of the installation part, the repair work is eliminated, and the work period can be shortened.

  In the present embodiment, an example in which the CCD camera 8 is used as the imaging device has been described. However, the present invention is not limited to this, and a TV camera, for example, may be used.

(Modification of the first embodiment)
In the modification of the first embodiment, a laser measuring instrument or a height sensor is used as a monitoring device instead of the CCD camera 8 of the first embodiment. This laser measuring instrument or height sensor detects the shape of the back wave that is in a welded state. Other configurations and operations are the same as those in the first embodiment, and thus description thereof is omitted.

  As described above, according to the present modification, the shape of the back wave is detected by the laser measuring instrument or the height sensor, and the welding condition of the automatic TIG welding apparatus 7 is controlled based on the shape of the back wave, whereby the first As in the first embodiment, it is possible to ensure sound welding quality of the installation portion and shorten the work period.

(Second Embodiment)
FIG. 6 is a front view showing a repair device and the like installed on the outer periphery side of the shroud in the second embodiment of the present invention. The same parts as those in the first embodiment are denoted by the same reference numerals, and only different configurations and operations will be described.

  As shown in FIG. 6, in this embodiment, a grinder 10 that can be remotely operated is mounted on the outer traveling carriage 8a, and a welding torch 12 and a wire supply device 13 that can be remotely operated are mounted on the other outer traveling carriage 8b. Is installed. The grinder 10, the welding torch 12, and the wire supply device 13 constitute the repair device of this embodiment.

  Therefore, in this embodiment, when a defect occurs during welding and the necessity of polishing from the outer peripheral side of the shroud 3 occurs, the defective part is polished by the grinder 10, and the welding torch 12 and the wire supply are supplied as necessary. Repair welding is performed by the device 13.

  As described above, according to the present embodiment, when a defect occurs in the welded portion welded by the automatic TIG welding device 7, it is possible to repair by a remote operation using the grinder 10, the welding torch 12, and the wire supply device 13. .

(Other embodiments)
Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  For example, the automatic TIG welding device 7 may be mounted on the inner traveling carriage 7a and the backing metal 11 may be attached to the outer traveling carriage 8a as in the above embodiments. Then, by moving the automatic TIG welding device 7 and the backing metal 11 in synchronization and performing welding, it is possible to perform more sound welding.

  Further, in each of the above embodiments, welding is performed by mounting the penetrant flaw test (PT: Penetrant Testing) penetrant jet head, cleaning liquid jet head, hot air dryer, black light, and CCD camera on the inner traveling carriage 7a. Later, it is possible to remotely perform the penetrant inspection work and the visual inspection work.

  DESCRIPTION OF SYMBOLS 1 ... Reactor pressure vessel, 2 ... Support cylinder, 3 ... Shroud, 4 ... Welding part, 5 ... Inner rail, 6 ... Outer rail, 7 ... Automatic TIG welding apparatus, 7a ... Inner traveling cart, 8 ... CCD camera (monitoring) Device), 8a ... outer traveling cart, 8b ... outer traveling cart, 10 ... grinder, 11 ... backing metal, 12 ... welding torch, 13 ... wire supply device, 15 ... control panel, 16 ... control device (movement control device, Welding control device), 17 ... CPU, 18 ... database, 19 ... input device, 20 ... display device

Claims (5)

A shroud installation device for installing a new shroud by welding on a support cylinder installed in a reactor pressure vessel,
An inner traveling carriage that travels along an inner rail installed along the inner periphery of the shroud;
A welding device mounted on the inner traveling carriage for welding between the support cylinder and a lower end groove portion of the shroud;
An outer traveling carriage that travels along an outer rail installed along an outer periphery of the shroud;
A monitoring device mounted on the outer traveling carriage and monitoring a welding state by the welding device;
A movement control unit for controlling the traveling speed of the inner traveling carriage and the outer traveling carriage so that the welding apparatus and the monitoring apparatus move in synchronization;
A welding control unit that controls welding conditions of the welding device based on a welding state monitored by the monitoring device;
A shroud installation device comprising:   2. The shroud according to claim 1, wherein the monitoring device monitors a welding state of any of a back bead width, a back wave shape, a groove width, and a melted area by the welding device. Installation device.   The shroud installation according to claim 1 or 2, wherein the welding control unit controls a welding current, a welding voltage, a welding speed, and a wire supply speed based on the welding state so as to satisfy an appropriate welding condition. apparatus.   The shroud installation device according to any one of claims 1 to 3, wherein the welding device is an automatic TIG welding device, and the monitoring device is a CCD camera. A shroud installation method in which a new shroud is installed on a support cylinder installed in a reactor pressure vessel by welding,
A welding step of moving along an inner rail installed along the inner periphery of the shroud and welding between the support cylinder and a lower end groove portion of the shroud by a welding device;
A monitoring step of moving in synchronization with the welding device along an outer rail installed along the outer periphery of the shroud and monitoring a welding state by the welding device with a monitoring device;
After the monitoring step, a welding control step for controlling welding conditions of the welding device based on a welding state monitored by the monitoring device;
A shroud installation method characterized by comprising:

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