JP2017009309A - Piping removal method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a piping removal method with no liquid left inside the piping capable of preventing a contaminant inside the piping from spreading into a surrounding environment while the piping is cut and cut piping is transported, and implementing the removal in a short period of time.SOLUTION: A piping removal method to separately remove a portion 1a of piping 1 with no liquid left inside the piping, comprises: a first process to drill through holes 2 and 3 on cutoff points 30 and 31 of the piping; a second process to spray liquid concentrate 20 of urethane foam on an inner periphery of the piping with a spray nozzle 11 inserted into the piping through the through hole; a third process to seal an interior of the portion of the piping with sealing plugs 21 and 22 made by allowing the liquid concentrate of the urethane foam to expand and solidify at the cutoff points; a fourth process to cut the portion of the piping including the sealing plugs at the cutoff points; and a fifth process to apply a coating material 23 to cut surfaces of the piping.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a method for removing a pipe, and more particularly, to a method for removing a pipe having a contaminant inside.

  When discarding the pipes laid in the plant, the pipes are generally cut, divided into several parts, and removed. At that time, for example, when the piping in the nuclear power plant is discarded, the inside of the piping is contaminated with radioactive substances, and therefore it is necessary to prevent the inside pollutants from diffusing into the surrounding environment when the piping is cut. .

  As a method of cutting a pipe in which contaminants are present, Patent Document 1 discloses that “a method of cutting a pipe filled with liquid inside, the step of making a hole in the side of the pipe, And a step of curing at least a part of the liquid by inserting a spray nozzle into the pipe and injecting a chemical solution into the pipe through the spray nozzle, and a step of cutting the pipe. “Pipe cutting method” is disclosed.

  Further, in Patent Document 2, “in a pipe cutting method for cutting a pipe containing fluid, a hole is formed in a pipe at a position to be cut, and high-pressure air is blown into the pipe from the hole to After the fluid is blown and moved to the left and right in the axial direction of the position to be cut in the pipe, a backup material is injected from the hole, and high pressure air is blown from the hole before the backup material is cured to pivot the backup material. By blowing left and right in the direction, a gap is formed at a position to be cut between the backup materials, and after the backup material is cured, the filler is injected and cured from the hole, and then the piping is cut. A pipe cutting method characterized by the above is disclosed.

  Further, in Patent Document 3, “in a pipe cutting method for cutting a pipe in which a fluid is present, a first hole is formed at a position to be cut in the pipe, and both axial sides of the first hole are formed. A second hole is formed in the pipe, and a bag is inserted into the pipe from the second hole, and the bag is inflated by injecting a backup material into the bag to partition the pipe. Then, a pipe cutting method characterized by injecting a filler into the pipe between the bags from the first hole and cutting the pipe after the filler is cured is disclosed.

  Further, Patent Document 4 states that “a small hole is formed at an appropriate position of a workpiece whose inner space is radioactively contaminated, and a synthetic resin solution that has a high curing speed and has no air permeability is filled into the workpiece from the small hole. A method for cutting a cut object whose internal space is radioactively contaminated is characterized in that the inside of the cut object is closed and the central part of the cut object and the cured synthetic resin liquid is cut after the synthetic resin is cured. '' ing.

JP2013-13909A Japanese Patent Laid-Open No. 9-297196 Japanese Patent Laid-Open No. 9-297197 JP 59-32899 A

  However, the pipe cutting method described in Patent Literature 1 is applicable to pipes filled with liquid inside, and cannot be applied to the removal work of pipes that do not have fluid inside such as steam pipes.

  On the other hand, the pipe cutting methods described in Patent Document 2 and Patent Document 3 are applicable to pipes in which no fluid is present, and include a process for retaining the filler at the cutting position of the pipe, and Since it takes time to cure the filler, there is a problem that the working time becomes long. In particular, when piping is removed in a nuclear power plant, the working environment is a high dose, and therefore, it is desired to apply a removal method that can be performed in a short number of steps and in a short time.

  In addition, although the pipe cutting method described in Patent Document 4 is applied to a pipe that does not have a fluid inside, “when the pipe (7) is inclined or along a vertical line, the pipe is cut. (7) It is necessary to form a weir using a balloon-type or diaphragm-type stopper below or above the injection site so that the synthetic resin liquid (9) stays at the cut site in Patent Document 2 and Patent Similar to Reference 3, there is a problem that the process time is increased because it involves a step for retaining the filler (synthetic resin liquid) at the cut site and it takes time to cure the filler.

  Furthermore, in the pipe cutting methods described in Patent Document 2 to Patent Document 4, during transportation of the divided pipe, the filler that seals the opening of the pipe peels off, so that pollutants inside the pipe are surrounded. There is also a risk of spreading to the environment.

  The present invention has been made in view of the above-described problems, and its object is to apply piping that does not have fluid inside, and pollutants inside the piping are present when the piping is cut and during transportation of the divided piping. It is intended to provide a pipe removal method that can prevent diffusion to the surrounding environment and can be carried out in a short time.

  In order to solve the above problems, the present invention is a pipe removal method for dividing and removing a part of a pipe in which no fluid is present, and a first step of drilling a through hole at a cutting position of the pipe; In the cutting position, a spray nozzle is inserted into the through-hole, and a foaming / curing material is sprayed onto the inner peripheral surface of the pipe, and the foaming / curing material is foam-cured to form a sealing plug. A third step of closing the inside of the pipe, a fourth step of cutting the pipe together with the sealing plug at the cutting position, and a fifth step of applying a paint to the cut surface of the pipe. Shall be.

  According to the present invention, the cutting position of the pipe is closed by the foam-curing material that foams and cures in a short time, and the paint is applied to the cut surface of the pipe, thereby removing the pipe that does not have fluid inside. It becomes possible to carry out in a short time without diffusing pollutants inside the pipe to the surrounding environment when cutting the pipe and during the transportation of the divided pipe.

It is an external view of the steam piping laid in the nuclear power plant and the inside was radioactively contaminated. In the piping removal method which concerns on 1st Example of this invention, it is a figure which shows the process of inserting the spray nozzle of foaming urethane spray in a through-hole, and spraying the foaming urethane stock solution on the internal peripheral surface of piping. In the piping removal method which concerns on 1st Example of this invention, it is a figure which shows the process of obstruct | occluding the inside of piping in the cutting position of piping by foam-curing a foaming hardening material and forming a sealing plug. It is a figure which shows a mode that the removal piping part is isolate | separated from the remaining piping part in the piping removal method which concerns on 1st Example of this invention. In the piping removal method which concerns on 1st Example of this invention, it is a figure which shows the state which sprayed the coating material on the both-side cut surface of a removal piping part, and the cutting surface of a residual piping part, respectively. In the piping removal method which concerns on 1st Example of this invention, it is a figure which shows a mode that a coating material is sprayed through the spray nozzle of a coating material spray to the lower cut surface of the removal piping part. In the piping removal method which concerns on 2nd Example of this invention, it is a figure which shows the process of inserting the spray nozzle of foaming urethane spray in the through-hole of piping, and spraying the foaming urethane stock solution on the internal peripheral surface of piping. In the pipe removal method concerning the 3rd example of the present invention, it is a figure showing the process of inserting the spray nozzle of foaming urethane spray into the penetration hole of piping, and spraying the stock solution of foaming urethane to the inner peripheral surface of piping.

  Embodiments of the present invention will be described below with reference to the drawings. In addition, in each figure, the same code | symbol is attached | subjected to the same member and the overlapping description is abbreviate | omitted suitably.

  Hereinafter, the pipe removing method according to the first embodiment of the present invention will be described. FIG. 1 is an external view of a steam pipe laid in a nuclear power plant and radioactively contaminated inside. In the present embodiment, as shown in FIG. 1, a method of removing a part of the pipe 1 along the vertical line (hereinafter referred to as “removed pipe part”) 1a will be described.

  First, as shown in FIG. 1, both end positions of the removed piping portion 1 a are set as cutting positions 30 and 31 of the piping 1, and through holes 2 and 3 having small diameters are respectively formed on the outer peripheral surfaces of the piping 1 at the cutting positions 30 and 31. Perforate.

  Next, the inner peripheral surface of the pipe 1 near the cutting positions 30 and 31 is cleaned by injecting water from the through holes 2 and 3.

  Next, as shown in FIG. 2, the spray nozzle 11 of the foamed urethane spray 10 is inserted into the through holes 2 and 3, and the foamed urethane stock solution 20 is sprayed onto the inner peripheral surface of the pipe 1. The foamed urethane stock solution 20 adhering to the inner peripheral surface of the pipe 1 is foamed and cured in a short time, and as shown in FIG. 3, the sealing plugs 21 and 22 block the inside of the pipe 1 at the cutting positions 30 and 31. Form. Here, the material of the sealing plugs 21 and 22 is not limited to urethane foam, and polystyrene foam, polystyrene foam, or the like can also be used. In this way, the sealing plugs 21 and 22 are formed at the cutting positions 30 and 31 regardless of the posture of the pipe 1 by forming the sealing plugs 21 and 22 with the foam curing material that foams and cures in a short time. Is possible.

  Next, as shown in FIG. 3, the pipe 1 is cut together with the sealing plug 21 at the cutting position 30 with the removed pipe portion 1 a fixed by the pipe fixing tool 40, and the pipe 1 is sealed at the cutting position 31. 22 and cut. By closing the pipes 1 at the cutting positions 30 and 31 with the sealing plugs 21 and 22, it is possible to prevent the contaminants inside the pipe 1 from diffusing into the surrounding environment when the pipe 1 is cut. Further, by fixing the removed pipe portion 1a with the pipe fixture 40 when the pipe 1 is cut, it is possible to prevent the removed pipe portion 1a from dropping after the pipe 1 is cut.

  Next, as shown in FIG. 4, the removed piping portion 1 a is separated from the remaining piping portions (hereinafter referred to as “remaining piping portions”) 1 b and 1 c.

  Next, as shown in FIG. 5, the coating material 23 is sprayed on the both side cut surfaces of the removed pipe portion 1a and the cut surfaces of the remaining pipe portions 1b and 1c. FIG. 6 is a view showing a state in which the paint 23 is sprayed to the lower cut surface of the removal pipe portion 1 a through the spray nozzle 13 of the paint spray 12. As the coating material 23 used here, a coating material having airtightness, waterproofness and anticorrosion properties such as a lining material is desirable. Thus, by spraying the coating material 23 on the both side cut surfaces of the removed pipe portion 1a, it is possible to prevent the sealing plugs 21 and 22 from peeling off from the both side cut surfaces of the removed pipe portion 1a. Moreover, by spraying the coating material 23 on the cut surfaces of the remaining pipe portions 1b and 1c, the sealing plugs 21 and 22 can be prevented from peeling off from the cut surfaces of the remaining pipe portions 1b and 1c, respectively.

  According to the pipe removing method according to the present embodiment, the foamed urethane stock solution 20 sprayed on the inner peripheral surface of the pipe 1 is foamed and cured in a short time to form the sealing plugs 21 and 22. Regardless of the case, the pipe 1 can be closed at the desired cutting positions 30 and 31. In addition, since a process for retaining the filler at the cutting positions 30 and 31 is not required, the operation time can be shortened.

  Furthermore, since the sealing plugs 21 and 22 can be prevented from peeling off from the both-side cut surfaces of the removal pipe portion 1a by spraying the paint 23 on the both-side cut surfaces of the removal pipe portion 1a, the posture of the removal pipe portion 1a is changed. Regardless, the removed piping portion 1a can be transported with the contaminants sealed inside.

  Furthermore, since the coating plugs 23 are sprayed on the cut surfaces of the remaining pipe portions 1b and 1c, respectively, the sealing plugs 21 and 22 can be prevented from peeling off from the cut surfaces of the remaining pipe portions 1b and 1c, respectively. It is possible to prevent the contaminants from diffusing from the cut surfaces of the remaining pipe portions 1b and 1c during the transportation of.

  Hereinafter, the pipe removing method according to the second embodiment of the present invention will be described. In the pipe removing method according to the first embodiment, air or the like when blowing the foamed urethane stock solution 20 to the inner peripheral surface of the pipe 1 winds up pollutants in the pipe 1, and the spray nozzle 11 and the through holes 2, 3. There is a risk of leakage into the surrounding environment from the gap. The pipe removal method according to this embodiment is an improvement of this point.

  FIG. 7 shows a process of inserting the spray nozzle 11 of the foamed urethane spray 10 into the through holes 2 and 3 of the pipe 1 and spraying the foamed urethane stock solution 20 onto the inner peripheral surface of the pipe 1 in the pipe removing method according to the present embodiment. FIG. This embodiment differs from the first embodiment (see FIG. 2) in that a flange member 14 is attached to the outer peripheral surface of the spray nozzle 11 of the urethane foam spray 10 as shown in FIG.

  The outer diameter of the flange member 14 is larger than the inner diameter of the through holes 2 and 3, and when the spray nozzle 11 is inserted into the through holes 2 and 3, the flange member 14 is brought into close contact with the outer peripheral surface of the pipe 1, thereby 2 and 3 are closed. The shape of the flange member 14 may be any shape as long as the through holes 2 and 3 can be closed when the spray nozzle 11 is inserted into the through holes 2 and 3. The method of closing the gap between the spray nozzle 11 and the through holes 2 and 3 is not limited to the above method. For example, the spray nozzle 11 and the through holes 2 and 3 are inserted after the spray nozzle 11 is inserted into the through holes 2 and 3. Alternatively, a method of filling a clay-like member into the gap may be used.

  According to the pipe removing method according to the present embodiment, in addition to obtaining the same effect as the first embodiment, the gap between the spray nozzle 11 and the through holes 2 and 3 is blocked by the flange member 14, When the foamed urethane stock solution 20 is sprayed onto the inner peripheral surface of the pipe 1, it is possible to prevent contaminants inside the pipe 1 from leaking into the surrounding environment from the gap between the spray nozzle 11 and the through holes 2 and 3.

  Hereinafter, the pipe removing method according to the third embodiment of the present invention will be described. In the pipe removal method according to the first embodiment, since the foamed urethane stock solution 20 is sprayed only on one place on the inner peripheral surface of the pipe 1, when applied to a pipe having a large inner diameter, The uneven distribution with respect to the axial center of the pipe 1 creates a gap between the inner peripheral surface of the pipe 1 and the sealing plugs 22 and 22 at the cutting positions 30 and 31, and internal pollutants leak to the surrounding environment during cutting. There is a risk. The pipe removal method according to this embodiment is an improvement of this point.

  FIG. 8 is a cross-sectional view of the pipe 1 at the cutting positions 30, 31. The spray nozzle 11 of the foamed urethane spray 10 is inserted into the through holes 2, 3 of the pipe 1, and the urethane foam stock solution is placed on the inner peripheral surface of the pipe 1. 20 is shown. As shown in FIG. 8, this embodiment is a first embodiment in that a nozzle head 15 in which a plurality of ejection holes are formed is attached to the tip of the spray nozzle 11 of the urethane foam spray 10. 2).

  The foamed urethane stock solution 20 sprayed from the foamed urethane spray 10 is sprayed from a plurality of spray holes of the nozzle head 15 and sprayed to a plurality of locations on the inner peripheral surface of the pipe 1. The foamed urethane stock solution 20 sprayed to the plurality of locations expands toward the axial center of the pipe 1, thereby forming sealing plugs 21 and 22 that are not biased with respect to the axial center.

  According to the pipe removing method according to the present embodiment, since the foamed urethane stock solution 20 is sprayed onto a plurality of locations on the inner peripheral surface of the pipe 1, the inside of the pipe 1 having a large inner diameter can be closed without a gap. The same effect as in the first embodiment can be obtained regardless of the size of the inner diameter of 1.

(Other)
The present invention is not limited to the above-described embodiments, and includes various modifications. For example, in the above-described embodiment, an example in which a part of the steam pipe is divided and removed has been described. However, the present invention is not limited to this, and even if the pipe has fluid in the pipe 1 during plant operation. As long as there is no fluid at least near the cutting position of the pipe at the time of cutting, it can be applied to any pipe.

  The above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Further, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, or the configuration of another embodiment can be added to the configuration of one embodiment. Furthermore, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

DESCRIPTION OF SYMBOLS 1 ... Piping, 1a ... Removal piping part, 1b, 1c ... Remaining piping part, 2, 3 ... Through-hole, 10 ... Urethane foam spray, 11 ... Spray nozzle, 12 ... Paint spray, 13 ... Spray nozzle, 14 ... Flange member , 15 ... Nozzle head, 20 ... Foam urethane stock solution, 21, 22 ... Seal plug, 23 ... Paint, 30, 31 ... Cutting position, 40 ... Piping fixture

Claims (4)

A pipe removal method that divides and removes part of a pipe that does not have fluid inside,
A first step of drilling a through hole at a cutting position of the pipe;
A second step of inserting a spray nozzle into the through hole and spraying a foam hardened material on the inner peripheral surface of the pipe;
A third step of closing the inside of the pipe at the cutting position by foaming and curing the foam-curing material to form a sealing plug;
A fourth step of cutting the pipe together with the sealing plug at the cutting position;
A pipe removing method, comprising: a fifth step of applying a paint to a cut surface of the pipe. A pipe removing method according to claim 1,
In the second step, the spray nozzle is inserted into the through hole, and a foamed and hardened material is sprayed on the inner peripheral surface of the pipe in a state where the gap between the spray nozzle and the through hole is closed. How to remove piping. A pipe removing method according to claim 1 or 2,
The spray nozzle has a nozzle head in which a plurality of ejection holes are formed,
In the second step, the foam removing material is sprayed onto the plurality of locations on the inner peripheral surface of the pipe from the plurality of ejection holes of the nozzle head. It is a piping removal method of Claim 1 thru | or 3, Comprising:
In the fourth step, the pipe removing method, wherein the pipe is cut together with the sealing plug at the cutting position in a state where a part of the pipe is fixed by a pipe fixing tool.

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