JP4045635B2 - Method for joining piping in reactor pressure vessel and groove aligning jig used in the method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a joining technique between a pipe in a reactor pressure vessel and a structure in the reactor pressure vessel, and particularly relates to a joining technique in an environment where it is difficult for humans to approach.
[0002]
[Prior art]
No technology has been implemented to replace the jet pump riser pipe, which is a pipe in the reactor pressure vessel joined to the nozzle of the reactor pressure vessel, with a new pipe without removing the shroud in the reactor pressure vessel.
[0003]
If this is to be done, the old jet pump riser tube is removed from the nozzle and removed, and the weld groove of the new jet pump riser tube carried into the reactor pressure vessel is aligned with the weld groove of the nozzle. The place where the jet pump riser pipe is equipped is a narrow space between the inner wall of the reactor pressure vessel and the shroud in the reactor pressure vessel, and under a high radiation environment. Due to the disaster, the work of aligning the welding groove and the welding joint work could not be performed.
[0004]
Even if the shroud is removed from the reactor pressure vessel to secure a large working space, there is a proposal that a person can directly access the vicinity of the nozzle using hiring and perform groove alignment and spot welding.
[0005]
[Problems to be solved by the invention]
The above prior art proposal is effective when there is no or low radiation dose received from the pipe for groove alignment and the surrounding equipment, etc., and it is effective when sufficient welding groove alignment time can be secured. If the amount of radiation received from the piping to be used and surrounding equipment is high, the possibility that the operator will be exposed to a large amount of radiation cannot be denied, and it is difficult to perform welding groove alignment and welding joint work in the reactor pressure vessel. It was.
[0006]
Accordingly, a first object of the present invention is to provide a method that facilitates welding groove alignment and welding joint work in a reactor pressure vessel, and a second object is to open a weld in a reactor pressure vessel. An object of the present invention is to provide a groove alignment jig that facilitates the alignment.
[0007]
[Means for Solving the Problems]
A first means for achieving the first object of the present invention is to move a suspended support pipe in a reactor pressure vessel in which a liquid is contained, so that a welding groove of the pipe is moved to the reactor pressure vessel. The welded groove of the installed tubular structure is brought close to the welded groove of the structure, and the welded groove of the pipe is connected to the welded groove of the structure from the outside of the reactor pressure vessel. Through the tubular structure This is a method of joining piping in a reactor pressure vessel in which the two welding grooves are aligned by pulling and then welding the two welding grooves, and the suspended piping is a reactor in which liquid is stretched. The inside of the pressure vessel is moved toward the tubular structure to be joined, the weld groove of the pipe approaches the weld groove of the tubular structure, and then the pipe is connected to the tubular structure from the outside of the reactor pressure vessel. The two welds of the pipe and the tubular structure are brought together and then welded between the two welds, and the welding groove alignment and welding are performed at the reactor pressure. Since the liquid is stretched in the vessel, the liquid functions to shield radiation, making it easier for workers to approach and aligning the welding groove and welding joints in the reactor pressure vessel. The effect of being easy to perform is obtained.
[0008]
Similarly, in the first means, the first means replaces the inside of the tubular structure and the pipe with gas, and then passes the welding means through the inside of the tubular structure from the outside of the reactor pressure vessel. In the reactor pressure vessel piping method in which both the weld grooves are welded together, and in addition to the effects of the first means, the inside of the piping and the tubular structure is There is an effect that the work of feeding the welding means to the welding groove and the welding joint work itself can be easily achieved in a gas atmosphere.
Similarly, the third means is the second means, wherein the tubular structure is a horizontal nozzle provided in a reactor pressure vessel, and the pipe is bent in the horizontal direction with the pipe axis direction directed vertically. The old jet pump riser pipe, which was previously installed according to the nozzle, is placed above the liquid level in the reactor pressure vessel. In Cutting and discharging the liquid contained in the old jet pump riser pipe and the nozzle and replacing it with the gas flowing in from the cut end of the old jet pump riser pipe after the cutting. In addition, an end of the nozzle outside the reactor pressure vessel is connected to a remote underwater groove aligning jig in which an axial adjustment block is incorporated so as to be movable in the length direction of the nozzle and is provided with a drainage channel that can be opened and closed. And then the liquid level in the reactor pressure vessel is raised to allow the liquid that has risen in the reactor pressure vessel to flow from the cut end of the old jet pump riser pipe after the cutting. , Separating the nozzle and the old jet pump riser pipe, removing the separated old jet pump riser pipe from the nozzle side, and then forming a weld groove on the nozzle. After that, a new jet pump riser pipe having a weld groove formed at the lower end is suspended to lower the new jet pump riser pipe into the reactor pressure vessel so that the two weld grooves approach each other. Extending the axial adjustment block to the inside of the new jet pump riser pipe, hooking the axial adjustment block horizontally on the new jet pump riser pipe, and pulling the axial adjustment block toward the nozzle Welding operation of the welding groove is performed, and then the nozzle and the new jet pump riser pipe are temporarily fixed so that the two welding grooves are not displaced, Take measures to stop the inundation, and then open the drainage channel to remove the liquid in the new jet pump riser pipe and the nozzle. Reacting with water, replacing with gas, and then removing the remote underwater groove aligning jig from the nozzle, and then inserting welding means into the nozzle to weld-join between the two weld grooves This is a method for joining piping in a pressure vessel, and the effect of the first means and the second means can be achieved by using the jet pump riser pipe in the reactor pressure vessel as a pipe and the nozzle as a tubular structure. The effect that the replacement | exchange operation | work of the jet pump riser pipe | tube in a pressure vessel can be achieved easily is acquired.
[0009]
A fourth means for achieving the second object of the present invention includes a closing plate that is detachably attached to an outer end of the reactor pressure vessel of a nozzle provided in the reactor pressure vessel and closes the end of the nozzle. An axial adjustment block drive shaft which is mounted on the closing plate and can be moved in the length direction of the nozzle to engage with a pipe in the reactor pressure vessel, and mounted on the closing plate. Groove fitting for use in a method of joining a piping in a reactor pressure vessel having a moving operation portion of the axial direction adjustment block drive shaft disposed on the opposite side of the engagement plate with the engagement portion This jig is used by attaching a closing plate to the end of the nozzle facing the outside of the reactor pressure vessel so as to close the end, and moving from the outside of the reactor pressure vessel. To adjust the axial adjustment block drive shaft Move in the direction of the pipe existing in the furnace pressure vessel, engage the pipe with the engaging section of the axial adjustment block drive shaft, and drive the axial adjustment block by operating the moving operation section By returning the shaft back to the inside of the nozzle, the pipe is pulled toward the nozzle side, and the action of aligning both the welding groove between the pipe and the nozzle is obtained. This action eliminates the need for workers to access the reactor pressure vessel. It is possible to easily achieve welding groove alignment between piping and nozzles in the reactor pressure vessel from the outside of the reactor pressure vessel, and to reduce radiation exposure of workers.
[0010]
Similarly, the fifth means is the groove aligning jig used in the method of joining the piping in the reactor pressure vessel, characterized in that in the fourth means, the closing plate is provided with an openable / closable drainage flow path. In addition to the effects of the fourth means, the nozzle closed with the closing plate, the liquid in the pipe combined with the nozzle is drained by opening the drainage channel, and at the time of welding joining work in a gas atmosphere, etc. The effect that it can contribute to the operation | work which replaces the atmosphere of a nozzle or piping with a gas atmosphere is acquired.
[0011]
Similarly, the sixth means is the fifth means according to the fifth means, wherein a holding plate is mounted on the groove alignment holding block so as to be movable back and forth in the radial direction of the pipe or nozzle, and the groove alignment holding block is mounted on the closing plate. A groove alignment holding block drive shaft that can be operated to move in the length direction of the nozzle, and the groove that is mounted on the closing plate and is arranged on the opposite side of the holding plate with the closing plate interposed therebetween. A groove aligning jig used in a joining method of piping in a reactor pressure vessel having a moving operation portion of a matching holding block drive shaft. In addition to the operation and effect of the fifth means, a groove is formed from the outside of the reactor pressure vessel. Move the groove holding block drive shaft to the pipe and nozzle welding groove alignment section by operating the alignment holding block drive shaft moving operation section, and then move the holding plate to the pipe or nozzle. Give effect to determine the radial position of the two weld groove against the vicinity welding GMA alignment advancing direction, precise welding GMA alignment effect is obtained.
[0012]
Similarly, the seventh means includes a purge balloon that communicates with the pressure supply flow path, and a purge balloon drive that is mounted on the closing plate and is operable to move the purge balloon in the length direction of the nozzle. A shaft, a moving operation portion of the purge balloon drive shaft which is mounted on the closing plate and is disposed on the opposite side of the purge balloon with respect to the closing plate, and a shield into the nozzle on the closing plate A groove aligning jig used in a method of joining a reactor pressure vessel pipe having a gas inlet, and purging by operating a moving operation portion of a purge balloon drive shaft outside the reactor pressure vessel. Advance the balloon drive shaft into the piping to position the purge balloon in the piping, then inflate the purge balloon, and then put the shield gas into the nozzle from the inlet, drainage flow path By opening and draining, the liquid can be drained from the area extending from the weld groove joint between the nozzle and the pipe to the nozzle, and the penetration of the liquid can be suppressed by a sealing function with a purge balloon, and the area from the weld groove joint to the nozzle can be controlled. The gas atmosphere with the shielding gas is replaced, and the effect that the temporary welding of both welding grooves in the state where the back side is shielded with the shielding gas can be performed reliably from the inside of the reactor pressure vessel is obtained. The effect of being able to improve the conditions of main welding by fixing the state of groove alignment with temporary fixing.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
In the reactor pressure vessel 2 in the nuclear power plant, when replacing the piping in the reactor pressure vessel, the upper end plate is removed so that the operator 31 can see the inside of the reactor pressure vessel from the work platform 30. Is done.
[0014]
In order to suppress the radiation exposure of the worker 31, water is extended to the pool above the reactor pressure vessel 2 and the radiation shielding function by water is used. Since this water is transparent, the operator 31 has a view in the reactor pressure vessel 2.
[0015]
In this reactor pressure vessel 2, a cylindrical shroud 1 surrounding the core is provided. In a narrow space between the shroud 1 and the inner wall of the reactor pressure vessel 2, a jet pump riser pipe (hereinafter simply referred to as an in-vessel piping 3) of a jet pump for circulating cooling water in the reactor pressure vessel via the reactor core. ) Exists as piping in the reactor pressure vessel. The jet pump riser pipe is connected to the inside of the reactor pressure vessel of the nozzle attached horizontally to the reactor pressure vessel, and a main circulation pipe (hereinafter simply referred to as an outside vessel pipe 5) is provided outside the reactor pressure vessel of the nozzle. It is connected as piping outside the reactor pressure vessel.
[0016]
The existing in-vessel piping 3 shown in FIG. 2 is removed from the reactor pressure vessel as the old in-vessel piping, but when removing it, consider the convenience when removing the existing outer vessel piping 5 Then do as follows.
[0017]
First, as shown in FIG. 2, the upper part of the existing in-vessel pipe 3 is cut to lower the water level in the reactor pressure vessel 2 by about 50 cm from the upper end of the existing in-vessel pipe 3. And the water in the existing pipe 5 outside the container is drained through the path of the existing pipe 5 outside the container.
[0018]
When such a drainage operation is performed, the inside of the existing in-container piping 3, the nozzle 4, and the existing out-of-container piping 5 is replaced from a liquid to a gaseous atmosphere.
[0019]
After such an atmosphere replacement operation, water, alcohol, or the like is poured into the existing vessel piping 3 from the upper part of the existing vessel piping 3 remaining in the reactor pressure vessel 2, The inside of the pipe 3, the nozzle 4 and the existing pipe 5 outside the container is cleaned, and decontamination is performed using cloth, sponge, etc., and the radiation exposure amount of the worker in the subsequent work is reduced.
[0020]
Next, as shown in FIG. 2, the vicinity of the joint portion 6 between the nozzle 4 and the existing container outer pipe 5 is cut with a grinder 7 or the like, and the existing container outer pipe 5 is separated from the nozzle 4. At the end of the cut nozzle 4 outside the reactor pressure vessel 2, a weld groove for welding the outer vessel pipe 5 again is processed.
[0021]
An operator engaged in such a cutting operation or a welding groove processing operation approaches the reactor pressure vessel 2, but the reactor pressure vessel 2 is filled with water having a function of shielding radiation. In addition, since the existing internal pipe 3 and nozzle 4 and the existing external pipe 5 are subjected to radiation decontamination by cleaning and decontamination, it is possible to minimize the radiation exposure of the worker. This makes it easy to perform cutting work and welding groove working work. After welding groove processing, the existing pipe 3 in the container 3 and the inside of the nozzle 4 are cut using cloth, sponge, etc. and the chips scattered in the existing pipe 3 in the container and nozzle 4 in the welding groove processing work. It collects and decontaminates, and reduces the radiation exposure of the worker in the subsequent work.
[0022]
Next, as shown in FIG. 1, a remote underwater groove aligning jig 9 is inserted into the nozzle 4 from the outside of the reactor pressure vessel 2, and the welding groove surface 8 outside the reactor pressure vessel of the nozzle 4 is attached to the jig. 9 so that it is covered with the closing plate 60.
[0023]
The edge portion facing the nozzle 4 of the flange portion 61 of the remote underwater groove alignment jig 9 is chamfered so that the flange portion 61 can be easily set on the nozzle 4.
[0024]
When the weld groove surface 8 and the inner surface of the flange portion 61 of the remote underwater groove aligning jig 9 are in contact with each other, the bolt 10 of the flange portion 61 is screwed to the nozzle 4 side to cause the remote underwater groove aligning jig 9 to move to the nozzle 4. Install in.
[0025]
An axial adjustment block drive shaft 11, a groove alignment holding block drive shaft 12, a purge balloon drive shaft 14, a shield gas inlet 15, and a drain cock 16 constituting the remote underwater groove alignment jig 9 are a closing plate 60. Is equipped. The axial adjustment block drive shaft 11, the groove alignment holding block drive shaft 12, and the purge balloon drive shaft 14 are rotatably installed on the closing plate 60 and are watertightly installed using the O-ring 22 as a sealing means. The adjusting male screw 17 is provided as a moving operation portion, the adjusting male screw 11a is screwed to the drive shaft adjusting female screw 17, the shaft section 11b having a polygonal cross section fixed to the inner end of the nozzle 4 of the adjusting male screw 11a, A cylindrical portion that fixes the guide portion 11c between the guide portion 11c and the closing plate 60 so that the guide portion 11c does not rotate. The structure 11d is provided.
[0026]
Since the drive shaft adjusting female screw 17 is prevented from moving in the axial direction of the nozzle 4 by the E-shaped retaining ring 18 or the like so as not to move in the axial direction of the nozzle 4 from the closing plate 60, it moves in the axial direction of the nozzle 4 It is only possible to rotate without it.
[0027]
Since the shaft section 11b having a polygonal cross section is inserted through a through-hole having the same cross section as the polygonal section formed in the guide section 11c, when the drive shaft adjusting female screw 17 is rotated, the adjusting male screw 11a is screwed to the in-container pipe 3 side. The shaft portion 11b can be moved to the in-container piping 3 side without rotation.
[0028]
An axial direction adjustment block 35 is fixed from the in-container pipe 3 of the shaft portion 11b of the axial direction adjustment block drive shaft 11 as shown in FIG. The axial adjustment block 35 has a bowl shape so as to serve as an engagement means with the in-container piping 3.
[0029]
The groove alignment holding block 37 includes a holding plate 45, and a groove holding arm 13 that extends and contracts the holding plate 45 with a pressure cylinder in the radial direction of the nozzle 4 has three points at an angular pitch of 120 degrees in the circumferential direction of the nozzle 4. The nozzle 4 is attached at two locations in the axial direction, that is, six locations in total. A groove holding plate 45 is attached to the tip of the groove holding arm 13. By extending the groove holding arm 13 with a pressure cylinder, the holding plate 45 aligns the groove alignment portion of the in-container pipe 3 and the nozzle 4. It has a structure that can be held in a heated state. Such a groove alignment holding block 37 has the same structure as that of the axial adjustment block drive shaft 11 and is supported by the groove alignment holding block drive shaft 12 attached to the closing plate 60, and the tip of the shaft portion 11b. It is fixed to.
[0030]
The purge balloon drive shaft 14 having the same structure as the axial adjustment block drive shaft 11 and attached to the closing plate 60 has a high pressure hose that allows the inside of the shaft portion 11b and the adjustment male screw 11a to enter and exit the purge balloon 20 from the outside. A hollow 19 structure connected to 62 is used as a gas path when the purge balloon 20 is inflated and deflated. A purge balloon 20 is provided at the tip of the hollow shaft portion 11b so as to communicate with the hollow 19 structure portion.
[0031]
Further, a pipe having both ends opened as a shield gas injection port 15 is fixed to the closing plate 60, and an inert gas supply source is communicated to one end of the pipe via a high-pressure hose 62a.
[0032]
Furthermore, although not shown in the figure, any cylindrical structure 11d is equipped with an internal monitoring camera via a pan head whose imaging direction is variable, and the imaging result of the internal monitoring camera is the reactor pressure vessel. 2 It has a configuration that can be displayed on an external monitor.
[0033]
After the remote underwater groove aligning jig 9 is installed in the nozzle 4 as shown in FIG. 1, the water level in the reactor pressure vessel 2 is raised from the upper end of the in-vessel piping 3, so that the in-vessel piping 3 and the nozzle 4 are placed inside. The water in the reactor pressure vessel 2 is drawn from the upper end of the vessel piping 3 and filled with water up to the closing plate 60 to increase the water shielding thickness of the radiation, so that the radiation from the central portion of the reactor pressure vessel to the nozzle 4 side is reduced. The shielding rate is improved, and the radiation exposure of workers who work near the nozzle 4 outside the reactor pressure vessel 2 is reduced.
[0034]
Even if water enters the nozzle 4, leakage of water is prevented by the closing plate 60, and water leakage is further ensured by the O-ring 21 attached to the flange portion 61 and the O-ring 22 attached to the closing plate 60. The structure can be blocked.
[0035]
Next, as shown in FIG. 3, the reactor pressure vessel 2, the in-vessel piping 3 and the nozzle 4 are filled with water in a state where the remote underwater groove aligning jig 9 is installed in the nozzle 4. The remote underwater grinder device 24 is installed in the vicinity 25 of the joint between the nozzle 4 and the in-container pipe 3 while monitoring the vicinity 25 of the joint between the nozzle 4 and the in-container pipe 3 using the monitoring camera 23. When installing the remote submersible grinder device 24 in the vicinity of the joint 25, the remote submersible grinder is suspended using a lifting machine such as an overhead crane or a chain block that moves above the reactor pressure vessel 2 as necessary. By operating the pole attached to the device 24, the insertion and installation work is performed on the narrow portion between the reactor pressure vessel 2 and the shroud 1. The remote underwater grinder device 24 may be installed and fixed using any one of the reactor pressure vessel 2, the in-vessel piping 3, and the nozzle 4, or a plurality of locations.
[0036]
The control lines and the like of the remote underwater grinder device 24 are installed without touching water to the air position above the reactor pressure vessel 2 through the inside of an operation pole attached to the device, and are connected to the control device. By adopting a hydraulic rotary motor as a drive source of the remote underwater grinder device 24, it is not necessary to provide a waterproof structure for the rotary shaft related part, and the structure of the entire device can be simplified and reduced in weight.
[0037]
The operator confirms the cutting position and the installation position of the remote underwater grinder device 24 as needed with the monitoring camera 23 or the like, and cuts the vicinity 25 of the joint between the in-container pipe 3 and the nozzle 4.
[0038]
The existing in-vessel piping 3 cut from the nozzle 4 side is removed from the reactor pressure vessel 2 by being suspended and moved by an overhead crane or a chain block.
[0039]
After that, as shown in FIG. 4, the remote underwater groove processing device 26 is operated from the upper part of the reactor pressure vessel 2 using the monitoring camera 23 without changing the water level in the vessel, and is installed near the cutting portion. .
[0040]
When installing the remote underwater groove processing device 26 in the container, if necessary, suspend it using an overhead crane, chain block, etc., and operate the pole attached to the remote underwater groove processing device 26. Then, the reactor pressure vessel 2 and the narrow portion of the shroud 1 are inserted and installed. The remote underwater groove processing device 26 is installed by fitting the inner surface of the guide flange 63 of the remote underwater groove processing device 26 to the nozzle 4 side while making contact with the outer surface of the cutting portion. The rotation center axis of the cutting blade 64 of the processing device 26, that is, the rotation drive shaft 65 is aligned. The inner surface of the guide flange 63 is inclined so that the inner diameter of the guide flange 63 on the nozzle 4 side is large and the inner diameter becomes smaller toward the inside of the reactor pressure vessel 2 so that the inner surface of the guide flange 63 can be smoothly fitted.
[0041]
The setting block 67 is brought into contact with the outer wall side of the shroud 1 by rotating the setting shaft 66 after aligning the shaft centers of the nozzle 4 and the remote underwater groove processing device 26 as described above using the guide flange 63. The inner surface of the guide flange 63 is fitted to the outer surface of the nozzle 4 so that the inner wall side of the reactor pressure vessel 2 and the guide flange 63 come into contact with each other. The remote underwater groove processing device 26 is connected to the outer wall of the shroud 1 and the inner wall of the reactor pressure 2. , And the rotational drive shaft 65 of the remote underwater groove processing device 26 is aligned with the central axis of the nozzle 4.
[0042]
In order to realize such a movement, links 70 and 71 are connected between the setting block 67 and the nuts 68 and 69 so as to be rotatable up and down around the shaft, and the nut 68 and the setting shaft 66 are connected to the setting shaft 66. The nut 69 and the setting shaft 66 are screwed together with the left screw formed on the setting shaft 66, and the setting shaft 66 is inserted into the processing device main body 72 of the remote underwater groove processing device 26. When the built-in setting shaft drive motor is driven in the same rotation direction, the nuts 68 and 69 are screwed in directions approaching each other, the links 70 and 71 are rotated in the horizontal direction, and the setting block 67 is pressed against the shroud 1. With this reaction force, the guide flange 63 fixed integrally with the processing apparatus main body 72 is pressed against the inner wall of the reactor pressure vessel 2. When the setting shaft 66 is rotated in the reverse direction, the above-mentioned pressing is released, and the remote underwater groove processing device 26 can be hung with an overhead crane or the like and removed from the spot.
[0043]
In the processing device main body 72 of the remote underwater groove processing device 26, a mechanism for moving the rotational drive shaft 65 in the axial direction of the shaft and a motor for rotationally driving the rotational drive shaft 65 are incorporated.
[0044]
The control lines and the like of each motor and mechanism in the processing apparatus main body 72 are guided to the upper part of the reactor pressure vessel 2 through the inside of the operation pole 73 attached to the processing apparatus main body 72 without touching water and connected to the control apparatus. Each motor and mechanism in the processing apparatus main body 72 can be controlled by the control device. By adopting a hydraulic rotary motor as the motor in the processing apparatus main body 72, the processing apparatus main body 72 is not required to have a waterproof structure, and the structure of the remote underwater groove processing apparatus 26 can be simplified and reduced in weight. .
[0045]
The operator confirms the groove processing position, the position of the cutting blade 64, and the like from time to time with the monitoring camera 23, the internal monitoring camera, and the like, and performs a groove processing operation for processing the welding groove on the left end of the nozzle 4. When processing the welding groove, in the state of FIG. 4, the rotary drive shaft 65 is advanced to the nozzle 4 side while rotating the rotary drive shaft 65 with a motor, and the cutting blade 64 is pressed against the left end of the nozzle 4. The left end of the nozzle 4 is cut with a cutting blade 64 to process a weld groove.
[0046]
When the groove working operation of the welding groove of the nozzle 4 is completed, the stretch of the remote underwater groove working device 26 that has been stretched between the shroud 1 and the reactor pressure vessel 2 is released, and the remote underwater is removed with an overhead crane or the like. The groove processing device 26 is hung and removed from the spot.
[0047]
Next, as shown in FIG. 5, the wire 28 is attached to the new in-vessel pipe 27, and the weight of the new in-vessel pipe 27 is attached to the overhead crane 29 in the reactor building or the chain block attached to the work platform 30. Hold. The operator 31 on the work platform 30 tied to the lower end of the new in-vessel piping 27 in order to carry the new in-vessel piping 27 into a predetermined position in the narrow portion between the reactor pressure vessel 2 and the shroud 1. While operating the guide rope 32 and using a monitoring camera or the like to check the groove portion, the guide rope 32 is smoothly moved to the nozzle 4 side. Since the weight of the new in-container pipe 27 is held by the overhead crane 29 or the chain block, the operation with respect to the new in-container pipe 27 by the guide rope 32 can be performed with a relatively small force. This method can also be applied to the above-described remote underwater grinder device 24, the remote underwater groove processing device 26, and the below-mentioned remote underwater welding device 42.
[0048]
This new in-container pipe 27 is used as a jet pump riser pipe by replacing the existing in-container pipe 3, and its lower part is smoothly bent at a right angle. The processed welding groove and the welding groove to be grooved are processed in advance before being carried into the reactor pressure vessel 2.
[0049]
As shown in FIG. 6, a rough guide 34 is attached to the outer periphery of the new container pipe 27 in the vicinity of the welding groove of the new container pipe 27. As shown in FIG. 6, the rough guide 34 is chamfered so that the nozzles can easily receive the nozzles 4 at the four side ends. Although the rough guide 34 has an annular structure as a whole, the structure divided into two is connected by bolts to form an annular shape as a whole. Therefore, the rough guide 34 can be removed from the new in-container pipe 27 by removing the bolt.
[0050]
Furthermore, a dedicated guide 33 is fixed to the inside of the new in-container pipe 27 and to the portion from the welding groove. The dedicated guide 33 has a shape that hooks with the axial adjustment block 35.
[0051]
Such a dedicated guide 33 and rough guide 34 are also installed in the new vessel piping 27 in advance before the new vessel piping 27 is carried into the reactor pressure vessel 2.
[0052]
As shown in FIG. 6, a welding groove corresponding to the nozzle 4 side of the new internal pipe 27 is operated by operating the overhead crane 29 and the guide rope 32 through the new internal pipe 27 in the reactor pressure vessel 2 filled with water. Is opposed to the left end of the nozzle 4.
[0053]
Next, in order to match the weld groove of the new in-vessel piping 27 and the nozzle 4 in the water in the reactor pressure vessel 2, the groove alignment operation is performed as follows.
[0054]
First, as shown in FIG. 6, when the welding groove existing at the lower end of the new container pipe 27 approaches the welding groove at the left end of the nozzle 4 and temporarily moves downward by about 100 mm, the remote underwater groove alignment jig is used. 9, the axial adjustment block 35 is extended into the new in-container pipe 27 by rotating the axial adjustment female screw 17 as a moving operation portion of the drive shaft 11.
[0055]
As described above, the axial adjusting female screw 17 is fixed by the E-shaped retaining ring or the like so as not to move in the nozzle 4 axis direction on the closing plate 60, and therefore can only rotate without moving in the nozzle 4 axis direction. It has become. On the other hand, the shaft portion 11b integrated with the adjusting male screw 11a screwed with the axial adjusting female screw 17 is only allowed to pass through the polygonal guide hole of the guide portion 11c and not be rotated and guided in the nozzle axial direction. Therefore, if the axial direction adjustment internal thread 17 is rotated, the adjustment external thread 11a is screwed and the shaft portion 11b is sent to the inside of the new in-container pipe 27. If the axial direction adjusting female screw 17 is reversed, the shaft portion 11b can move in the direction of returning to the nozzle 4 side.
[0056]
In this way, the axial adjustment block 35 moves the shaft portion 11 b of the axial adjustment block drive shaft 11 through the dedicated guide 33 inside the new container pipe 27 and further into the new container pipe 27. Since the dedicated guide 33 has a left-upward slope on the side facing the nozzle 4, the axial direction adjustment block that has moved when the axial direction adjustment block 35 coming from the right is moved into the inside of the new container pipe 27. Even if 35 slightly interferes with the dedicated guide 33, it has a shape that easily moves over the upper part of the dedicated guide 33 and into the pipe. Further, since the dedicated guide 33 has a protrusion directed toward the center of the reactor pressure vessel, and the axial adjustment block 35 has a protrusion opposite to the direction of the protrusion, the axial adjustment block 35 is once dedicated. The special guide 33 and the axial adjustment block 35 are structured so as not to easily come off when the upper part of the guide 33 is overcome.
[0057]
Next, as shown in FIG. 7, the overhead crane 29 and the guide rope 32 are placed with the axial adjustment block 35 located on the left side, that is, on the inner side and the upper side of the dedicated guide 33 inside the new container pipe 27. By operating, the new container inner pipe 27 is pulled up and brought close to the height relation state where the axial direction adjustment block 35 and the dedicated guide 33 inside the new container inner pipe 27 are engaged.
[0058]
Here, if the new in-container pipe 27 is pulled up too much, the axial adjustment block 35 interferes with the inner lower part of the new in-container pipe 27 or the shaft portion 11b to which the axial adjustment block 35 is fixed interferes with the dedicated guide 33. . Which of the interferences depends on the inclination of the new in-container pipe 27, but when it is vertical, the interference occurs only when the new in-container pipe 27 is pulled up too much. When pulling up the new in-container pipe 27, the operator 31 who operates the new in-container pipe 27 from the work platform 30 keeps the new in-container pipe 27 in a vertical posture by the image from the monitoring camera 23. It operates, confirming the welding groove position of the piping 27 and the nozzle 4 in a new container.
[0059]
Further, the operator who operates the remote underwater groove aligning jig 9 observes the vicinity of the welding groove position by the internal monitoring camera and grasps the axial direction adjusting female screw 17, so that the axial direction adjusting block driving shaft 11 is operated. Vibration that can be felt by the hand of the worker who is gripping the axial adjustment female screw 17 by being transmitted to the axial adjustment female screw 17 when the axial part 11b or the axial adjustment block 35 interferes with the dedicated guide 33 or the new pipe 27 in the container. Thus, the positional relationship between the dedicated guide 33 and the axial adjustment block 35 can be sensed. The worker 31 on the work platform 30 and the operator who operates the remote underwater groove alignment jig 9 perform the groove alignment operation while confirming the operation status of each other using a transceiver or the like.
[0060]
When the distance from the worker 31 on the work platform 30 to the position for groove alignment is large, it is better to use the rough guide 34. However, since the outer surface of the rough guide is covered with the synthetic resin material, the nozzle 4 Even if it contacts the side groove surface, the possibility of damage is low, and the groove surface on the new container pipe 27 side is not damaged.
[0061]
However, when the rough guide 34 is used, it is difficult to monitor the groove alignment portion from the outer surface of the new in-container pipe 27. Therefore, when the rough guide 34 is used, it is determined whether or not the rough guide 34 can be used by performing examination tests such as mock-up in the factory.
[0062]
After the state of FIG. 7 is secured, as shown in FIG. 8, the overhead crane 29, the guide rope 32, etc. are placed in a state where the axial direction adjustment block 35 is located inside the dedicated guide 33 inside the new in-container pipe 27. By operating the pipe 27 in the new container to be vertical, and further rotating the axial direction adjusting female screw 17 of the axial direction adjusting block drive shaft 11 in the reverse direction to move the shaft portion 11b back to the nozzle 4 side, the dedicated guide 33 is caught by the axial adjustment block 35, and the new in-container pipe 27 is hooked by the axial adjustment block drive shaft 11. In this state, when the shaft portion 11b of the axial direction adjustment block drive shaft 11 is further moved back to the nozzle 4 side, the lower end of the new container pipe 27 is drawn toward the left end of the nozzle 4 and the rough guide 34 is moved to the nozzle 4. The welding groove at the lower end of the new in-container pipe 27 and the welding groove at the left end of the nozzle 4 are aligned with each other.
[0063]
When the new container pipe 27 is pulled toward the nozzle 4 side, the overhead crane 29, the guide rope 32, etc. are operated in synchronism with the amount of the pull so that the upper end of the new container pipe 27 is also on the nozzle 4 side. The new in-container pipe 27 is moved in the vertical direction by moving to the position, so that it is possible to eliminate the tilting defect from the vertical posture of the welded groove when the welded groove is aligned, thereby contributing to highly accurate groove alignment.
[0064]
When the rough guide 34 is used, it is necessary to match the outer surface of the weld groove at the left end of the nozzle 4 with the inner surface of the rough guide 34, but the inner diameter of the right end of the rough guide 34 is larger than the outer surface of the nozzle 4. Since it is 30 mm larger and is inclined so as to be 5 mm larger in diameter than the outer surface of the nozzle 4 on the side closer to the weld groove of the new inner pipe 27, the central axis of the nozzle 4 and the new inner pipe 27 If the displacement is 10 mm or less, the inclined surface where the new guide pipe 27 and the nozzle 4 are welded to the rough guide 34 by aligning the new guide pipe 27 and the nozzle 4 by pulling the new guide pipe 27 to the nozzle 4 side. It can be performed as a guide surface.
[0065]
The confirmation of the groove alignment state is mainly based on the image from the inside of the nozzle 4 by the monitoring camera 23 from the outside of the pipe and the internal monitoring camera equipped in the remote underwater groove alignment jig 9. During the adjustment work of the adjustment female screw 17, the distance from the rearmost end (right end) of the adjustment female screw 17 to the rearmost end (right end) of the adjustment male screw 11a is measured with a caliper or the like in a state where the adjustment has been completed to the groove alignment position in advance. On the other hand, the working time is shortened by checking the numerical value recorded as optimum and operating the adjustment female screw 17 of the axial adjustment block drive shaft 11 so as not to exceed the recorded value.
[0066]
After the groove aligning operation has progressed in this way, as shown in FIG. 9, the groove aligning holding block 37 is opened to the new in-container pipe 27 side by rotating the adjusting female screw 17 of the groove aligning holding block drive shaft 12. Move toward the point-to-point section.
[0067]
As described above, the adjustment female screw 17 of the groove alignment holding block drive shaft 12 is the E-shaped retaining ring so that it does not move in the axial direction of the nozzle 4 on the closing plate 60, like the adjustment female screw 17 of the axial adjustment block drive shaft 11. It is possible to rotate only without moving in the nozzle 4 axis direction. Similar to the axial adjustment block drive shaft 11, when the adjustment female screw 17 of the groove alignment holding block drive shaft 12 is rotated, the adjustment male screw 11 a is screwed, and the shaft portion 11 b integrated with the adjustment male screw 11 a is the axial direction of the nozzle 4. Can be moved to. Along with this movement, the groove alignment holding block 37 integral with the shaft portion 11b can also move in the same direction.
[0068]
Here, the holding block 37 is moved to the position shown in FIG. 9 so that the holding plate 45 on the new inner pipe 27 side faces the groove aligning portion, and then all the holding plates 45 are moved as shown in FIG. Press with pressure cylinder.
[0069]
Here, since the holding block 37 on the new container pipe 27 side is pressed across the end of the new container pipe 27 and the end of the nozzle 4, the welding groove at the lower end of the new container pipe 27 and the left end of the nozzle 4 are welded. The groove is regulated in the radial direction of the pipe.
[0070]
When the adjustment female screw 17 is rotated when the groove alignment holding block 37 is moved, the rear end (right end) of the adjustment female screw 17 in the state where the movement to the groove alignment position has been completed in advance is the last end ( The working time is shortened by operating the adjusting female screw so as not to exceed the recorded value while checking the recorded value by measuring the distance to the right end) with a caliper or the like.
[0071]
At this time, as shown in FIG. 10, the holding plate 45 attached to the holding arm 39 is pressed against the inner surface of the nozzle 4 so that the groove alignment holding block drive shaft 12 is moved between the closing plate 60 on the right end side of the nozzle 4 and the nozzle 4. Since it can be fixedly supported at two points near the left end, the groove alignment accuracy in the radial direction of the nozzle 4 can be reliably improved.
[0072]
In this way, after supporting the groove alignment holding block drive shaft 12 at two points in the longitudinal direction of the groove alignment holding block drive shaft 12, the holding plate 45 attached to the holding arm 40 is then welded to the groove alignment portion. By pressing against the straddled portion, the groove can be accurately aligned, and the state where the groove is aligned can be stably held.
[0073]
Finally, in confirming the groove alignment state, the monitoring camera 23 from the outside of the pipe 27 in the new container and the internal monitoring camera installed in the remote underwater groove alignment jig 9 are used to monitor the monitoring camera from the inside and outside of the groove. Use video.
[0074]
In FIG. 11, the purge balloon 20 is moved into the new container pipe 27 by rotating the adjusting female screw 17 of the purge balloon drive shaft 14.
[0075]
Since the purge balloon drive shaft 14 has a drive mechanism similar to that of the axial adjustment block drive shaft 11 described above, the purge balloon drive shaft 14 is rotated when the adjustment female screw 17 of the purge balloon drive shaft 14 is rotated to feed the adjustment male screw 11a. The shaft portion 11b moves toward the new container pipe 27, and the purge balloon 20 reaches the bent part of the new container pipe 27. Here, the high pressure gas is supplied to the purge balloon 20 through the hollow portion of the high pressure hose 62 and the purge balloon drive shaft 14 to inflate the purge balloon 20, thereby partitioning the inside of the new container pipe 27 so that water and gas cannot pass therethrough. .
[0076]
Regarding the rotational adjustment of the adjusting female screw 17 for moving the purge balloon, it is necessary to push the purge balloon 20 into the inside of the new container pipe 27 as much as possible, so that a caliper or the like is moved from the adjusting female screw 17 to a position where the adjusting male screw 11a cannot be removed. Adjust the rotation while using and checking.
[0077]
After partitioning in the new container pipe 27 by the purge balloon 20, the shield gas is filled into the new container pipe 27 and the nozzle 4 from the shield gas inlet 15 via the high-pressure hose 62a. At this time, since the shielding gas is lighter than the water inside the new container pipe 27 and the nozzle 4, the shield gas is collected above the inside of the new container pipe 27 and the nozzle 4. In order to prevent the internal pressure inside the new container pipe 27 and the nozzle 4 from becoming too large due to the injection of the shielding gas, the drain cock 16 can be opened to discharge the water inside and adjust the internal pressure. Is possible.
[0078]
The shield state is also confirmed by video through a monitoring camera lowered from above into the new container pipe 27 and an internal monitoring camera attached to the remote underwater groove fitting jig 9.
[0079]
Next, the bolt that has tightened the half-rough guide 34 is lowered by removing the jig from above and removed to divide the rough guide 34 into two parts and removed from the pipe 27 in the new container. As shown in FIG. Make sure that the alignment part appears on the outside.
[0080]
Thereafter, as shown in FIG. 12, the remote underwater spot welder 42 is lowered from above, and the remote underwater spot welder 42 of the remote underwater spot welder 42 is placed on the outer surface of the groove joint portion between the pipe 27 in the new container and the nozzle 4. The chamber part 43 is brought into close contact, and three or more spot weldings are performed above the groove alignment part from the back side of the welding groove on the outer surface side of the pipe, and both welding grooves of the pipe 27 in the new container and the nozzle 4 are pointed. Temporarily weld by welding.
[0081]
When installing the remote underwater spot welding machine 42 to the welding groove, it is suspended using an overhead crane 29, a chain block, etc. as necessary, and the pole attached to the remote underwater spot welding machine 42 is attached. By operating, the insertion and installation are performed in the narrow part between the reactor pressure vessel 2 and the shroud 1. When the remote underwater spot welder 42 is held, the remote underwater spot welder 42 is light in weight, so it is possible to simply fix the pole by hand.
[0082]
When the rough guide 34 is used, a step for removing the remote underwater spot welding machine 42 is added before the remote underwater spot welding machine 42 is installed. However, this interferes with the adhesion of the remote underwater welder chamber 43 to the outer surface of the groove alignment portion. When the rough guide 34 as shown in FIG. 21 is used, the work of removing the bolt 74 and splitting the rough guide 34 in two may be performed after the spot welding is completed.
[0083]
The above-mentioned spot welding is performed after the inside of the remote underwater welder chamber 43 in close contact with the groove alignment portion is filled with a shielding gas. In addition, since the groove alignment part may be submerged from the surroundings, the shielding gas begins to flow 30 minutes before spot welding, and the monitoring camera disposed inside the chamber indicates that the outer surface of the pipe inside the chamber has completely dried. Perform spot welding after confirmation. When it is desired to shorten the drying time, it can be realized by heating with a heater or the like on the side where the shielding gas flowing inside the chamber is supplied from above the container.
[0084]
At the time of spot welding, the purge balloon 20 is inflated in the pipe 27 in the new container as described above, and the region between the purge balloon 20 and the closing plate 60 is filled with the shielding gas, so that the inside of the groove is filled. Is not oxidized, and the subsequent main welding can be easily performed. Further, when the groove is dried, the shielding gas is present in the upper part on the inner side, so that the drying is easy.
[0085]
After completion of the spot welding from the back side of the groove, the water level in the reactor pressure vessel 2 is lowered from the upper end of the new vessel piping 27, the purge balloon 20 is contracted as shown in FIG. 17 is reversed to return the purge balloon 20 to the initial position in the nozzle 4. After returning the holding plate 45 to the original position, the adjustment female screw 17 of the groove alignment holding block drive shaft 12 is reversed to return the groove alignment holding block 37 to the original position.
[0086]
Next, the water in the new container pipe 27 and the nozzle 4 is discharged to the outside by opening the drain cock 16, and the drain cock 16 is closed again. If the discharged water is contaminated by radiation, it must be collected in a dedicated container.
[0087]
At this point, water is present outside the new container pipe 27, but the weld groove joint between the new container pipe 27 and the nozzle 4 is spot welded from the outside of the pipe to open both weld grooves. In order to prevent water from entering the inside of the pipe as much as possible, in the unlikely event of spotted water, the pipe internal water so that the purge chamber is in close contact with the outer surface of the groove alignment pipe as shown in FIG. The prevention device 44 is installed so as to cover the groove alignment portion from the outer periphery of the groove alignment portion. Similarly to the rough guide, the pipe internal water immersion prevention device 44 is assembled so as to cover the groove aligning portion from the outer periphery by hanging the pipe internal water immersion prevention device 44 divided into two parts and fastening them with bolts.
[0088]
The inside of the pipe internal flood prevention device 44 is filled with a shielding gas to prevent water from entering the interior. After confirming that the inside is not flooded by an internal monitoring camera or the like equipped in the remote underwater groove adjusting jig 9, the remote underwater groove adjusting jig 9 is removed.
[0089]
In the removal operation, first, the adjustment female screw 17 of the axial adjustment block drive shaft 11 is rotated to separate the axial adjustment block 35 from the dedicated guide 33 to the left as shown in FIG.
[0090]
Next, as shown in FIG. 14, the bolt 10 of the flange portion 61 of the closing plate 60 is loosened to remove the remote underwater groove aligning jig 9 from the nozzle 4, and the right side of FIG. Pull out as long as 35 does not interfere. The operation is performed while confirming the state with an internal monitoring camera or the like equipped in the remote underwater groove alignment jig 9.
[0091]
Next, as shown in FIG. 15, the adjustment female screw 17 of the axial adjustment block drive shaft 11 is further rotated to move the axial adjustment block 35 away from the dedicated guide 33 to the left side.
[0092]
This state is checked while checking with an internal monitoring camera or the like equipped in the remote underwater groove fitting jig 9.
[0093]
Next, as shown in FIG. 16, the remote underwater groove aligning jig 9 is further pulled out from the nozzle 4 to the right side within the range where the dedicated guide 33 and the axial direction adjustment block 35 do not interfere with each other, and then the dedicated guide 33 and the axial direction adjustment are performed. The remote underwater groove aligning jig 9 is set to an obliquely upwardly inclined posture so that the block 35 does not interfere with the entire remote underwater groove aligning jig 9 and is completely extracted out of the nozzle 4 and removed. This operation is also performed while checking with an internal monitoring camera or the like attached to the remote underwater groove alignment jig 9 so that the constituent parts of the remote underwater groove alignment jig 9 do not interfere with the inner surface of the nozzle 4.
[0094]
After removing the remote underwater groove aligning jig 9 from the nozzle 4, clean the piping 27 in the new container and the inside of the nozzle 4, and when decontaminated water adheres to the inside, the decontamination is also included. Do.
[0095]
Thereafter, as shown in FIG. 17, the inner surface welding device 46 is inserted, the bolt 47 of the flange portion 77 of the shielding plate 76 is tightened, and the inner surface welding device 46 is installed in the nozzle 4.
[0096]
The inner surface welding device 46 has the following configuration.
[0097]
That is, the shielding plate 76 is equipped with a cylindrical circumferential drive shaft 49 so as to be rotatable about the same axis as the central axis of the nozzle 4 as a rotation axis. A motor 78 is connected to the circumferential drive shaft 49 via a gear, and the motor 78 is attached to the shielding plate 76. For this reason, when the motor 78 is driven, the circumferential drive shaft 49 can rotate about the same axis as the central axis of the nozzle 4 via the gear. A frame 80 is fixed in the hollow portion of the circumferential drive shaft 49, and an axial drive shaft 48 and two guide rods 79 are combined with the frame 80 so as to be movable in the axial direction of the nozzle 4.
[0098]
The axial drive shaft 48 is formed with a female screw, and the female screw is engaged with a nut that is given only a degree of freedom of rotation to the frame 80. A gear is fixed to the outer periphery of the nut, and a gear attached to the rotational drive shaft of the motor 81 is engaged with the gear. The motor 81 is fixedly installed on the frame 80.
[0099]
The left ends of the axial drive shaft 48 and the two guide rods 79 are fixed to a support frame 82 of the welding head. The support frame 82 is equipped with a welding torch 83 of the welding equipment so as to be movable in the radial direction of the nozzle 4 by the arc length adjustment drive unit 50. Furthermore, although not shown, the internal monitoring camera can also freely take the photographing direction. It is equipped via a pan head so that it can be changed.
[0100]
Such an inner surface welding device 46 is closed by covering the right end of the nozzle 4 with the shielding plate 76 so as to fit the right end of the nozzle 4 inside the flange portion 77 and closing the bolt 47 as shown in FIG. The bolt end is attached to the nozzle 4 so as not to come off.
[0101]
After the inner surface welding device 46 is mounted on the nozzle 4, when the motor 81 is operated and the rotational driving force of the motor 81 is transmitted to the nut via the gear, the nut rotates and the axial drive shaft 48 is moved to the left side (new pipe in the container). Project in the direction of 27). At this time, the two guide rods 79 project in the same direction as the projecting direction of the axial drive shaft 48 while preventing the axial drive shaft 48 and the support frame 82 from rotating.
[0102]
As shown in FIG. 18, when the welding torch 83 reaches the position in the axial direction that coincides with the welding line 52 of the welding groove, as shown in FIG. 18, the motor 81 is stopped. Subsequently, as shown in FIG. 18, the welding torch 83 is moved so as to approach the welding line 52 by the arc length adjustment driving device 50 so that an appropriate welding arc length can be obtained.
[0103]
Thereafter, an arc is generated from the welding torch 83 and the main welding of the welding groove between the new in-container pipe 27 and the nozzle 4 is performed from the inside of the new in-container pipe 27 and the nozzle 4. In this main welding, the motor 78 is operated to rotate the circumferential drive shaft 49, whereby the welding torch 83 is moved around along the welding line 52 and the entire circumference is welded.
[0104]
The first layer welding in the main welding is performed at least in the outer surface purge state by the pipe internal water leakage prevention device 44, so that the groove portion is completely melted. In the remaining layer welding, the pipe internal water leakage prevention device 44 is used. It is also possible to improve the residual stress due to welding by removing the outer water-cooling welding.
[0105]
When the above main welding is completed, the motor 81 is reversed to draw the axial drive shaft 48 and the two guide rods 79 into the axial drive shaft 49, and then the bolt 47 is loosened to remove the shielding plate 76 from the nozzle 4. The entire inner surface welding device 46 is extracted from the nozzle 4.
[0106]
After that, the dedicated guide removing grinder device 53 having the same structure as the welding torch of the inner surface welding device 46 is replaced with the grinder 55 is attached to the right end of the nozzle 4 in the same manner as the inner surface welding device 46, and the motor 81 is operated to be used exclusively. The grinder 55 is fed to a position reaching the guide 33, and the circumferential drive shaft 49 is rotated by the operation of the motor 78 to move in the circumferential direction, and the arc length adjusting drive device 50 moves in the radial direction of the new pipe 27 in the container. Is applied to the grinder 55, and the dedicated guide 33 is not cut by the grinder 55.
[0107]
The dedicated guide removing grinder device 53 replaces the grinder 55 with the welding torch portion of the inner surface welding device 46 and shares the remaining mechanism portion, but may be newly prepared without sharing.
[0108]
Thereafter, the dedicated guide removal grinder device 53 is extracted from the nozzle 4 in the same manner as the inner surface welding device 46.
[0109]
By changing the mounting angle of the grinder 55 to the arc length adjusting drive device 50, the dedicated guide removing grinder device 53 can also be used as a repair device for the welded portion of the welding groove.
[0110]
Next, the shavings by the grinder device 55 are cleaned and removed.
[0111]
Finally, as shown in FIG. 20, the vessel outer pipe 5, which has a weld groove at the left end in advance, is aligned with the right end of the nozzle 4, and the weld groove between the container outer pipe 5 and the nozzle 4 is aligned.
[0112]
Thereafter, the welding groove between the container outer pipe 5 and the nozzle 4 is welded from the outside of the pipe by a welding machine 84.
[0113]
When the container outer pipe 5 is also desired to be a new outer pipe, the new outer pipe is welded to the right end of the nozzle 4.
[0114]
In this way, the pipe replacement work is completed.
[0115]
When this method is applied to a reactor pressure vessel, a pipe inside the vessel is used as a jet pump riser pipe, a nozzle is used as a recirculation system piping inlet nozzle, and a pipe outside the vessel is used as a recirculation system piping, Compared to the case where the operator adjusts the groove in the air by draining the water in the pressure vessel, the surrounding water shields the radiation, so the amount of radiation exposed to the worker can be drastically reduced. Become.
[0116]
Also, in this construction method, a groove aligning jig is arranged outside the pipe, spot welding is performed from the inside of the pipe, and main welding is performed by underwater welding from the outside of the pipe. In comparison, it is possible to reduce the exposure amount of the worker.
[0117]
For this reason, in the pipe replacement of the narrow portion in the reactor pressure vessel, it becomes possible to perform groove alignment of the narrow portion that uses water for shielding and is difficult for humans to access under high radiation.
[0118]
【The invention's effect】
According to the invention of claim 1, each operation of welding groove alignment and welding joining of the piping and the tubular structure in the reactor pressure vessel is performed in a state where a liquid is stretched in the reactor pressure vessel. The liquid exhibits the function of shielding the radiation, making it easy for the operator to approach, and obtaining the effects of facilitating welding groove alignment and welding joining work in the reactor pressure vessel.
[0119]
According to the invention of claim 2, in addition to the effect of the invention of claim 1, the work of feeding the welding means to the welding groove and the welding joint work itself are performed by making the inside of the pipe and the tubular structure a gas atmosphere. The effect that it can be easily achieved is obtained.
[0120]
According to the invention of claim 3, the effect that the replacement work of the jet pump riser pipe in the reactor pressure vessel can be easily achieved is obtained.
[0121]
According to the fourth aspect of the present invention, it is possible to easily achieve the weld groove alignment between the pipe and the nozzle in the reactor pressure vessel from the outside of the reactor pressure vessel without requiring the operator to access the reactor pressure vessel. The effect that the radiation exposure of workers can also be reduced is obtained.
[0122]
According to the invention of claim 5, in addition to the effect of the invention of claim 4, the nozzle and the liquid in the pipe combined with the nozzle are drained by opening the drainage flow path, and welding joining work in a gas atmosphere The effect of easily replacing the atmosphere of the nozzles and piping necessary for the operation with a gas atmosphere can be obtained.
[0123]
According to the invention of claim 6, in addition to the effect of the invention of claim 5, the radial position of the pipe in the reactor pressure vessel is corrected with respect to the nozzle, and both the weld groove of the pipe and the nozzle are welded. Thus, it is possible to accurately perform the positioning in the radial direction and to improve the accuracy of welding groove alignment.
[0124]
According to the invention of claim 7, in addition to the effect of the invention of claim 6, the state of accurate groove alignment by the holding plate is fixed by temporary fixing, and the condition of the main welding after temporary fixing can be improved. The effect that it can be obtained.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing a state in which a remote underwater groove alignment jig according to an embodiment of the present invention is set on a nozzle of a reactor pressure vessel.
FIG. 2 is a longitudinal cross-sectional view schematically showing a state of cutting a joint portion between a nozzle and a container outer pipe by a grinder in an embodiment of the present invention.
FIG. 3 is a longitudinal sectional view schematically showing a state of cutting a joint portion between a nozzle and a container inner pipe by a remote underwater grinder in the embodiment of the present invention.
FIG. 4 is a longitudinal sectional view showing a state of a nozzle groove working operation using a remote underwater groove working machine according to an embodiment of the present invention.
FIG. 5 is a longitudinal cross-sectional view showing the operation of carrying in the new vessel piping into the reactor pressure vessel in the embodiment of the present invention.
FIG. 6 is a longitudinal sectional view showing a first stage of preparation for drawing the piping in the new container toward the nozzle in the embodiment of the present invention.
FIG. 7 is a longitudinal sectional view showing a second stage of preparation for drawing the piping in the new container to the nozzle side in the embodiment of the present invention.
FIG. 8 is a longitudinal cross-sectional view showing a state after drawing the pipe in the new container to the nozzle side in the embodiment of the present invention.
FIG. 9 is a longitudinal sectional view showing an operation state of the remote underwater groove aligning jig in the first stage after drawing the pipe in the new container to the nozzle side in the embodiment of the present invention.
FIG. 10 is a longitudinal sectional view showing an operation state of the remote underwater groove aligning jig in the second stage after drawing the new in-container piping toward the nozzle in the embodiment of the present invention.
FIG. 11 is a longitudinal sectional view showing a state of shielding in the pipe by the remote underwater groove aligning jig after aligning the groove in the new container and the nozzle in the embodiment of the present invention.
FIG. 12 is a conceptual diagram of a situation of remote underwater spot welding work in an embodiment of the present invention.
FIG. 13 is a longitudinal sectional view showing a first stage of the removal work of the remote underwater groove alignment jig in the embodiment of the present invention.
FIG. 14 is a longitudinal sectional view showing a second stage of the removal work of the remote underwater groove alignment jig in the embodiment of the present invention.
FIG. 15 is a longitudinal sectional view showing a third stage of removal work of the remote underwater groove alignment jig in the embodiment of the present invention.
FIG. 16 is a longitudinal sectional view showing the final stage of the removal work of the remote underwater groove alignment jig in the embodiment of the present invention.
FIG. 17 is a longitudinal sectional view showing a setting state of the inner surface welding apparatus to the nozzle in the embodiment of the present invention.
FIG. 18 is a longitudinal sectional view showing an inner surface welding operation state in the embodiment of the present invention.
FIG. 19 is a longitudinal sectional view showing a dedicated guide removing operation situation in the embodiment of the present invention.
FIG. 20 is a longitudinal sectional view showing a welding work situation between the nozzle and the pipe outside the container in the embodiment of the present invention.
FIG. 21 is a perspective view showing a modified rough guide adopted in the embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Shroud, 2 ... Outer vessel (reactor pressure vessel), 3 ... In-vessel piping, 4 ... Nozzle, 5 ... Outer vessel piping, 6 ... Nozzle and outer vessel junction, 9 ... Remote underwater groove alignment jig DESCRIPTION OF SYMBOLS 10 ... Bolt of a flange part, 11 ... Axial direction adjustment block drive shaft, 12 ... Groove alignment holding block drive shaft, 14 ... Purge balloon drive shaft, 15 ... Shield gas injection port, 16 ... Drain cock, 17 ... Drive shaft Adjustment female screw, 20 ... purge balloon, 24 ... remote underwater grinder device, 26 ... remote underwater groove processing device, 27 ... pipe in new container, 33 ... dedicated guide, 34 ... rough guide, 35 ... axial adjustment block, 44 ... Piping internal flooding prevention device, 46 ... inner surface welding device, 53 ... dedicated guide removal grinder device.

Claims (7)

The suspended support pipe is moved in the reactor pressure vessel in a liquid state, and the weld groove of the pipe is brought close to the weld groove of the tubular structure equipped in the reactor pressure vessel, The welded groove of the pipe is drawn from the outside of the reactor pressure vessel through the tubular structure to the welded groove of the structure, and the two welded grooves are aligned. Method of piping in reactor pressure vessel that welds and welds. In Claim 1, after replacing the inside of the tubular structure and the inside of the pipe with gas, the welding means is fed in the direction approaching both welding grooves through the inside of the tubular structure from the outside of the reactor pressure vessel, Then, a method for joining the piping in the reactor pressure vessel, in which both the weld grooves are welded together. 3. The jet pump riser according to claim 2, wherein the tubular structure is a horizontal nozzle provided in a reactor pressure vessel, and the pipe has a pipe axis direction directed vertically and a lower end bent horizontally. a tube, and cutting the old jet pump riser pipe which has Toritsui than before to the nozzle at above the liquid level in the reactor pressure vessel, contains the old jet pump riser pipe and the inner nozzle The discharged liquid is discharged and replaced with the gas flowing in from the cutting end of the old jet pump riser pipe after the cutting, and then the axial adjustment block is assembled to be movable in the length direction of the nozzle. And a remote underwater groove aligning jig provided with an openable and closable drainage channel, the outer end portion of the reactor pressure vessel of the nozzle is closed, and then the reactor The liquid level in the power vessel is raised and the rising liquid in the reactor pressure vessel is introduced from the cut end of the old jet pump riser pipe after the cutting, and the nozzle and the old jet pump riser pipe And disconnect the old jet pump riser pipe from the nozzle side, and after forming a weld groove in the nozzle, suspend a new jet pump riser pipe having a weld groove formed at the lower end. The new jet pump riser tube is lowered into the reactor pressure vessel so that the weld grooves approach each other, and then the axial adjustment block is extended to the inside of the new jet pump riser tube to Hook the new jet pump riser pipe horizontally with the direction adjustment block and pull the axial adjustment block toward the nozzle side. After performing the groove alignment operation of the two welding grooves, the nozzle and the new jet pump riser pipe are temporarily fixed to prevent the two welding grooves from being displaced, and then the two welding grooves are aligned. And then, the drainage channel is opened to drain the liquid in the new jet pump riser pipe and the nozzle and replace it with gas, and then the remote underwater groove is aligned from the nozzle. A method for joining piping in a reactor pressure vessel, characterized in that after removing a jig, a welding means is placed in the nozzle and the two welding grooves are welded together. Removably attached to an outer end of the reactor pressure vessel of a nozzle provided in the reactor pressure vessel, and a closing plate for closing the end of the nozzle, and attached to the closing plate, the inside of the reactor pressure vessel An axial adjustment block drive shaft that can be operated to move the engagement portion that can be engaged with the pipe in the length direction of the nozzle, and the engagement portion that is mounted on the closing plate and is opposite to the engagement portion with the closing plate interposed therebetween A groove aligning jig used in a method for joining a piping in a reactor pressure vessel having a moving operation portion of the axial direction adjusting block drive shaft arranged on the side. 5. A groove aligning jig according to claim 4, wherein the closing plate is provided with an openable / closable drainage flow path. The length of the nozzle according to claim 5, wherein the holding plate is attached to the groove alignment holding block so as to be movable back and forth in the radial direction of the pipe or nozzle, and the groove alignment holding block is attached to the closing plate. A groove alignment holding block drive shaft that is movable in a direction, and a groove alignment holding block drive shaft that is mounted on the closing plate and is disposed on the opposite side of the holding plate with respect to the holding plate. A groove aligning jig used in a method for joining piping in a reactor pressure vessel having a moving operation unit. 7. The purge balloon communicated with a pressure supply passage, the purge balloon drive shaft attached to the closure plate and capable of moving the purge balloon in the length direction of the nozzle, and the closure plate And a purge balloon drive shaft moving operation unit disposed on the opposite side of the purge plate from the purge balloon, and a shield gas injection port into the nozzle on the closure plate A groove aligning jig used in a method for joining piping in a reactor pressure vessel.

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