JP2009031013A - Method for surface treatment of weld zone in nuclear reactor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for giving a highly efficient and low-cost surface treatment to members such as a reactor pressure vessel and in-pile structures constituting a reactor. <P>SOLUTION: The water jet peening on a weld zone 6 is carried out by a self-propelled water jet peening device 21 mounted on rails 11a and 12a for guiding welding equipment used to weld the weld zone 6. The water jet peening on a weld zone 7 is also carried out by a self-propelled water jet peening device 21 mounted on rails 11b and 12b for guiding welding equipment used to weld the weld zone 7. Additionally, the water jet peening on a weld zone 8 is carried out by a self-propelled water jet peening device 21 mounted on rails 11c and 12c for guiding welding equipment used to weld the weld zone 8. The present method can also be applied to other surface treatments including laser property modification. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a surface treatment method for a welded portion of a reactor constituent member including a reactor pressure vessel and a reactor internal structure, and in particular, efficiency improvement such as water jet peening and laser modification performed before the operation of the reactor. About.

  Most of the reactor pressure vessel, reactor internal structure and piping, etc. constituting the nuclear reactor (in the present specification, these are collectively referred to as “reactor constituent members”) are made of austenitic stainless material. Since it is manufactured and exposed to a high-temperature corrosive environment, a surface treatment for preventing the occurrence of stress corrosion cracking is applied to predetermined portions before the operation of the nuclear reactor. This surface treatment includes methods for improving residual stress, such as water jet peening, shot peening, shot blasting, sand blasting, and cryoblast, which leave compressive stress in the weld, and surface treatment by irradiating the treatment with a laser beam. The surface modification method etc. which perform this are proposed conventionally (for example, refer patent documents 1, 2).

  The welded parts of the nuclear reactor components include welded parts welded at the factory and welded parts welded at the power plant site. The welded parts welded at the factory are stored in a surface treatment facility installed in the factory. The required surface treatment is performed, and the welded portion welded at the power plant site is subjected to the required surface treatment at the power plant site.

  As an example of a water jet peening facility provided in a factory, FIG. 4 of Patent Document 1 shows a device holding frame provided in a water storage tank and a device suspended from above the water storage tank. A high-pressure water injection nozzle disposed opposite to the welded portion of the retained nuclear reactor component, and while rotating the nuclear reactor component by the equipment holding frame, along the required weld from the high-pressure water injection nozzle It has been disclosed that cavitation bubbles are generated by jetting high-pressure water and an impact pressure associated with the collapse of the cavitation bubbles is applied to the weld.

On the other hand, as a surface treatment method of the welded portion performed at the power plant site, a method of hanging a self-propelled robot equipped with a surface treatment device from above the reactor pressure vessel has been proposed.
JP-A-8-105994 JP-A-11-90830

  As described above, the conventional surface treatment method for a reactor weld portion requires a water storage tank equipped with an equipment holding gantry that can rotationally drive the reactor structural members and a robot with a special structure. There is a problem. Moreover, since the head device for surface treatment such as a high-pressure water jet nozzle has to be remotely operated, it is difficult to accurately position the head device with respect to the welded portion, and the surface treatment of the welded portion is appropriately and efficiently performed. There is also a problem that it is difficult to do.

  The present invention has been made to eliminate such deficiencies in the prior art, and its problem is to enhance the surface treatment applied to members such as the reactor pressure vessel and the reactor internal structure that constitute the reactor. The object is to provide an efficient and low-cost method.

  In order to solve the problems of the prior art, the present invention provides a surface treatment method for a reactor weld that firstly performs a surface treatment on a weld of a reactor constituent member including a reactor pressure vessel and a reactor internal structure. In the welding of the nuclear reactor structural member, a surface treatment apparatus is mounted on a welding apparatus guide means provided on the nuclear reactor structural member or outside the nuclear reactor structural member, and the surface treatment is performed on the welded portion. And

  Since the welding device guide means guides the welding device along the required welded portion, if the surface treatment device is attached to the welding device guide means, the positioning of the surface treatment device with respect to the welded portion can be facilitated. It is possible to optimize the surface treatment for the welded portion and increase the efficiency. In addition, since it is not necessary to equip the surface treatment equipment with an equipment holding base capable of rotating and driving the nuclear reactor components, or to newly provide guide means dedicated to the surface treatment, the equipment cost for the surface treatment can be suppressed. .

  Secondly, in the surface treatment method of the first nuclear reactor welded portion, the present invention attaches the surface treatment device to a welding device guide means provided in the immediate vicinity of the welded portion to be surface treated. It is characterized by that.

  According to such a configuration, the surface treatment apparatus can be positioned more easily and accurately with respect to the welded portion to be subjected to the surface treatment, so that the surface treatment on the welded portion can be performed more appropriately and efficiently.

  Thirdly, the present invention is characterized in that, in the surface treatment method of the first reactor weld portion, a welding apparatus guide rail attached to the reactor constituting member is used as the welding apparatus guide means.

  Reactor structural members such as a core shroud and a shroud support are formed by combining a plurality of tubular bodies, and are manufactured by welding connection portions of the respective tubular bodies. And welding of each tubular body installs a ring-shaped welding apparatus guide rail along the inner peripheral surface and outer peripheral surface of one tubular body, and this welding apparatus guide rail can run a welding apparatus including a welding torch. Mounting is performed by driving the welding apparatus while traveling along the welding apparatus guide rail. Thereby, welding of each tubular body can be performed automatically, and a required nuclear reactor structural member can be manufactured efficiently. The welding device guide rail is usually removed after the welding of a required welded portion is completed. If a surface treatment device such as a water jet peening device or a laser reforming device is attached to the welding device guide rail so as to be able to run, the surface of the welding device guide rail is removed. Surface treatment of welded parts can be performed automatically without the equipment holding rack that can rotate the reactor components in the treatment equipment, or without the addition of rails dedicated to surface treatment to the tubular body. The equipment cost can be suppressed. Further, when the surface treatment device is attached to the welding device guide rail, the distance between the welding device guide rail and the welded portion is known, and therefore the positioning of the surface treatment device with respect to the welded portion is facilitated. Can be optimized and efficient.

  Fourth, the present invention is characterized in that a welding robot is used as the welding device guide means in the surface treatment method of the first reactor weld.

  For reactor components that are welded by a welding robot, a surface treatment device such as a high-pressure water jet nozzle is attached to the tip of the welding robot in place of the welding torch so that the surface treatment device can be accurately applied to the weld. Therefore, the surface treatment for the welded portion can be performed easily and appropriately.

  Fifth, according to the present invention, in the surface treatment method for the first reactor weld portion, the surface treatment for the required weld portion is performed in a manufacturing plant of the reactor pressure vessel or the reactor internal structure. It is characterized by that.

  According to such a configuration, since welding of a required portion and surface treatment for the welded portion can be performed in the manufacturing plant, the amount of work at the power plant site can be reduced, and the reactor can be efficiently constructed. be able to.

  Sixth, the present invention is characterized in that, in the surface treatment method for the first reactor weld portion, the surface treatment for the required weld portion is performed at a power plant site where the reactor pressure vessel is installed. To do.

  According to such a configuration, since the surface treatment for the welded portion can be performed even at the power plant site, the number of places where the surface treatment is performed can be increased, and the stress corrosion cracking resistance of the nuclear reactor can be improved.

  Hereinafter, the surface treatment method for the reactor weld according to the embodiment will be described with reference to FIGS. 1 to 7 by taking the surface treatment method for the weld of the core shroud as an example. 1 is a cross-sectional view of a core shroud to which a self-propelled water jet peening apparatus is attached via a welding apparatus guide rail, FIG. 2 is an enlarged cross-sectional view of part A of FIG. 1, and FIG. 3 is a view of the core shroud when the pool is shallow 4 is a cross-sectional view showing a first stage of the manufacturing procedure, FIG. 4 is a cross-sectional view showing a second stage of the manufacturing procedure of the core shroud when the pool is shallow, and FIG. 5 is a third stage of the manufacturing procedure of the core shroud when the pool is shallow. FIG. 6 is a cross-sectional view showing a state in which the welding apparatus guide rail is attached to the lower end portion of the core shroud, and FIG. 7 is a cross-sectional view of a principal part showing water jet peening for the welded portion of the core shroud and the shroud support. .

  As shown in FIG. 1, a core shroud 1, which is a reactor internal structure, includes an upper flange 2, an upper trunk 3, a lower flange 4, and a lower trunk 5, and includes a lower end of the upper flange 2 and an upper end of the upper trunk 3. Welding the butting portion, the butting portion between the lower end of the upper barrel 3 and the upper end of the lower flange 4, and the butting portion between the lower end of the lower flange 4 and the upper end of the lower barrel 5 from the outer peripheral side and the inner peripheral side. Are integrated. The welded portion 6 between the upper flange 2 and the upper body 3 is not shown on the outer peripheral rail 11a and the inner peripheral rail 12a for guiding the ring-shaped welding device installed by spot welding or the like on the outer surface and inner surface near the lower side of the upper flange 2. A self-propelled automatic welding apparatus is attached, and welding is performed by driving the self-propelled automatic welding apparatus along the rails 11a and 12a. Similarly, the welded portion 7 between the upper body 3 and the lower flange 4 is provided with a self-propelled automatic welding device on the outer rail 11b and the inner rail 12b for guiding the welding device installed on the outer surface and the inner surface near the lower side of the upper shell 3. The welded portion 8 of the lower flange 4 and the lower body 5 is welded by being attached to the outer peripheral rail 11c and the inner peripheral rail 12c for guiding the welding apparatus installed on the outer surface and the inner surface of the lower flange 4 on the lower side. It is welded by attaching an automatic welding device. Welding of the welded parts 6, 7, and 8 can be performed simultaneously at a plurality of locations by attaching a plurality of self-propelled automatic welding apparatuses to different welding apparatus guide rails, or one self-propelled automatic welding apparatus. Can be performed for each location by sequentially replacing the rails with other welding apparatus guide rails. Other specific welding methods are well-known matters and are not the gist of the present invention, and thus description thereof will be omitted.

  The outer peripheral rails 11a to 11c and the inner peripheral rails 12a to 12c for guiding the welding apparatus are formed to have the same width and thickness so that a self-propelled automatic welding apparatus having the same configuration can be attached. In addition, each of these rails is detachably installed on the core shroud 1 by spot welding or the like so that it can be removed after completion of required welding work and surface treatment work. Each of these rails can be installed at each part of the core shroud 1 at the same time, or can be replaced with another part every time welding and surface treatment for one welded part are completed.

  As shown in FIG. 1, the welded core shroud 1 is installed in a pool 13 and water jet peening is performed on the welds 6, 7, and 8. The water level 14 of the pool 13 is adjusted to a position where a weld to be subjected to water jet peening is submerged. Water jet peening for the welded portion 6 is performed by a self-propelled water jet peening device 21 attached to the welding device guide rails 11a and 12a left in the core shroud 1 even after the end of welding. Similarly, the water jet peening for the welded portion 7 is performed by the self-propelled water jet peening device 21 attached to the welding device guide rails 11 b and 12 b remaining in the core shroud 1. Peening is performed by a self-propelled water jet peening apparatus 21 attached to the welding apparatus guide rails 11c and 12c left in the core shroud 1.

  In this way, the water jet peening of the welded portion 6 is performed by the self-propelled water jet peening apparatus 21 attached to the rails 11 a and 12 a used for welding the welded portion 6, and the rail 11 b used for welding the welded portion 7. The self-propelled water jet peening device 21 attached to the rails 11c and 12c used for welding the welded portion 8 is implemented by the self-propelled water jet peening device 21 attached to the welded portion 8. When the water jet peening of the welded portion 8 is performed by the above, the distances from the rails 11a to 11c and 12a to 12c to the welded portions 6, 7, and 8 are known and are the shortest, so the surface treatment is performed. Easier and more accurate positioning of surface treatment equipment with respect to welded parts Ukoto can, it is possible to perform the surface treatment for the weld proper and efficient. In addition, when the self-propelled water jet peening device 21 is attached to the rails 11a to 11c and 12a to 12c used for welding the welded portions 6, 7, and 8, the apparatus holding device capable of rotating and driving the nuclear reactor components in the surface treatment facility. Since it is not necessary to provide a gantry or a new guide means dedicated to the surface treatment, the equipment cost for the surface treatment can be suppressed.

  As shown in FIG. 2, the self-propelled water jet peening apparatus 21 includes a carriage portion 22, a vertical guide roller 23 and a horizontal guide roller that attach the carriage portion 22 to rails 11 a to 11 c and 12 a to 12 c for guiding a welding apparatus. 24, a traveling roller 25 that travels the carriage unit 22 along the rails 11a to 11c and 12a to 12c for guiding the welding apparatus, a drive unit 26 of the traveling roller 25 provided in the carriage unit 22, and the carriage unit 22 as well. And a high-pressure water jet nozzle 28 for water jet peening that is fixed to the nozzle mounting portion 27 and whose nozzle tip is directed to a required welded portion. Cables 29 including signal cables are connected, and a water supply hose 30 is connected to the high-pressure water injection nozzle 28. The mounting of the self-propelled water jet peening device 21 to the required welding device guide rail, the driving / stopping of the self-propelled water jet peening device 21 and the like are performed remotely from the pool side.

  The water jet peening for the welds 6, 7, and 8 is performed by driving the traveling roller 25 by the drive unit 26 and causing the self-propelled water jet peening device 21 to travel along the required welding device guide rails. By spraying high pressure water from the nozzle 28 toward the required welds 6, 7, 8, by causing the impact pressure generated when the cavitation bubbles generated thereby are applied to the required welds 6, 7, 8, Do. Since the compressive stress remains in the welds 6, 7, and 8 due to the impact pressure, the stress corrosion cracking resistance is improved as compared with the case where the tensile stress due to welding remains.

  In addition, when the depth of the pool 13 is shallower than the full length of the core shroud 1, after welding the upper flange 2 and the upper trunk | drum 3, as shown in FIG. The body is installed in the pool 13, and the water jet peening device 21 is attached to the rails 11 a and 12 a installed on the upper trunk 3 to perform water jet peening of the welded portion 6. Similarly, after welding the lower flange 4 and the lower body 5, as shown in FIG. 4, the connecting body of the lower flange 4 and the lower body 5 is installed in the pool 13, and the rail 11 c installed on the lower body 5. , 12c, a water jet peening apparatus 21 is attached, and water jet peening of the welded portion 8 is performed. Thereafter, the upper shell 3 connected to the upper flange 2 and the lower flange 4 connected to the lower shell 5 are welded to form a core shroud 1, and the welded core shroud 1 is pooled 13 as shown in FIG. The water jet peening device 21 is attached to the rails 11b and 12b installed on the upper body 3 and the welded portion 7 is subjected to water jet peening. Thereby, the required core shroud 1 in which the water jet peening is applied to the welds 6, 7, and 8 is manufactured.

  After the water jet peening for the welds 6, 7, and 8 is completed, all the rails 11 a to 11 c and 12 a to 12 c used for the welding of the welds 6, 7, and 8 and the water jet peening are removed from the core shroud 1.

  This core shroud 1 is transported to the power plant site and welded to the shroud support in the reactor pressure vessel installed at the power plant site. Prior to transport to the power plant site, as shown in FIG. A ring-shaped outer rail 11d for welding apparatus and an inner rail 12d are installed on the outer surface and the inner surface of the lower shell 5 constituting the core shroud 1 by means of spot welding or the like. As the rails 11d and 12d, any of the rails 11a to 11c and 12a to 12c used for the welding work of the welded portions 6, 7, and 8 and the water jet peening work can be used.

  Welding work of these welded parts 6, 7, 8; water jet peening work for the welded parts 6, 7, 8; removing work of the rails 11a to 11c and 12a to 12c from the core shroud 1, and rail 11d for the core shroud 1. The installation work of 12d is performed in the manufacturing factory of the core shroud 1. As a result, the amount of work at the power plant site can be reduced, and the construction of the reactor can be made more efficient.

  As shown in FIG. 7, the core shroud 1 transported to the power plant site is arranged concentrically with the shroud support 32 provided in the reactor pressure vessel 31 and is automatically welded (not shown) attached to the rails 11d and 12d. Welded by the device. Next, after the automatic welding device is removed from the rails 11d and 12d, and the self-propelled water jet peening device 21 is attached to the rails 11d and 12d, water is poured into the reactor pressure vessel 31 and the core shroud 1 and the shroud support 32 are supplied. In this state, the self-propelled water jet peening apparatus 21 is driven to perform water jet peening on the weld 33. The self-propelled water jet peening device 21 is attached to the rails 11d and 12d, and the self-propelled water jet peening device 21 is driven and stopped from a work deck (not shown) provided above the reactor pressure vessel 31. This is done by remote control. After the water jet peening for the welded portion 33 is completed, the rails 11d and 12d are removed from the core shroud 1. This work is also performed by remote control from the work deck.

  Thus, in the manufacturing plant of the core shroud 1, the rails 11d and 12d are installed on the outer surface and the inner surface of the lower shell 5 constituting the core shroud 1, so that water jet peening for the welded portion 33 welded at the power plant site is performed. Can be performed easily and appropriately, and the reliability of the nuclear reactor can be further enhanced.

  In the above-described embodiment, the water jet peening method for the welds 6, 7, and 8 for manufacturing the core shroud 1 and the weld 33 for connecting the core shroud 1 and the shroud support 32 has been described as an example. The gist of the present invention is not limited to this, and can also be applied to water jet peening for welds applied to in-core structures other than the core shroud 1 and various pipes.

  Examples of the reactor internal structure other than the core shroud 1 include a control rod guide tube, a core support plate, an upper lattice plate, a steam separator, and a steam dryer. Among these in-furnace structures, those that are welded using a welding robot equipped with a welding torch at the tip of the welding apparatus guide arm are submerged in the furnace structure after welding and welding is performed. Water jet peening is performed on a required weld by attaching a water jet peening device to the tip of the welding device guide arm instead of the torch. Thereby, the water jet peening of the welded portion can be easily and appropriately performed on the in-furnace structure having a non-cylindrical complicated shape.

  Moreover, in the said embodiment, although demonstrated by taking water jet peening as an example of the surface treatment method of a welding part, the summary of this invention is not limited to this, The structure of a welding part is irradiated by laser irradiation. It can also be applied to laser modification to improve the resistance to stress corrosion cracking.

It is sectional drawing of the core shroud in which the self-propelled water jet peening apparatus was attached via the welding apparatus guide rail. It is the A section expanded sectional view of FIG. It is sectional drawing which shows the 1st step of the manufacturing procedure of a core shroud in case a pool is shallow. It is sectional drawing which shows the 2nd step of the manufacturing procedure of a core shroud in case a pool is shallow. It is sectional drawing which shows the 3rd step of the manufacturing procedure of a core shroud in case a pool is shallow. It is sectional drawing which shows the attachment state of the welding apparatus guide rail to the lower end part of a core shroud. It is principal part sectional drawing which shows the water jet peening with respect to the welding part of a core shroud and a shroud support.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Core shroud 2 Upper flange 3 Upper trunk 4 Lower flange 5 Lower trunk 6, 7, 8, 33 Welded part 11a-11c, 12a-12c Rail 21 Self-propelled water jet peening apparatus 22 Cart part 23 Vertical guide roller 24 Horizontal guide Roller 25 Traveling roller 26 Drive part 27 Nozzle mounting part 28 Nozzle 29 Cables 30 Water supply hose 31 Reactor pressure vessel 32 Shroud support

Claims (6)

In the surface treatment method of the reactor weld that applies a surface treatment to the weld of the reactor constituent member including the reactor pressure vessel and the reactor internal structure,
A surface treatment device is mounted on a welding device guide means provided on or outside the reactor component when welding the reactor component, and the surface treatment is performed on the welded portion. Surface treatment method for reactor welds.   2. The surface treatment method for a reactor weld according to claim 1, wherein the surface treatment apparatus is attached to a welding apparatus guide means provided in the immediate vicinity of a weld to be subjected to the surface treatment.   2. The surface treatment method for a reactor weld according to claim 1, wherein a welding apparatus guide rail attached to the reactor constituting member is used as the welding apparatus guiding means.   The surface treatment method for a reactor weld according to claim 1, wherein a welding robot provided outside the reactor constituent member is used as the welding apparatus guiding means.   The surface treatment method for a reactor weld according to claim 1, wherein the surface treatment for the weld is performed in a manufacturing factory of the reactor constituent member. The surface treatment method for a reactor weld according to claim 1, wherein the surface treatment for the weld is performed at a power plant site where a reactor pressure vessel is installed.

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