JP2013167564A - Closing member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a closing member capable of reliably closing a pipeline penetrating through a radiation shielding wall at a desired position.SOLUTION: A closing member 10 is, for example, used for closing pipelines 12a to 12d penetrating through a radiation shielding wall 24 for isolating a reactor body 20 from the outside, and is a member for closing a pipeline 12a by expansion due to pouring of fluid for expansion. The closing member 10 partitions an internal space as a plurality of balloons 40a and 40b, the balloons 40a and 40b have injection ports 41a and 41b of fluid, respectively, and the respective balloons 40a and 40b can be expanded independently from each other.

Description

  The present invention relates to a closing member for closing a pipe installed so as to penetrate a radiation shielding wall that shields a nuclear reactor main body or the like having a high radioactivity level.

  At the nuclear power plant, in order to shield the area with high radiation level from the outside, such as the area where the reactor main body consisting of the pressure vessel and the containment vessel is installed, a configuration in which this area is partitioned by a radiation shielding wall is adopted. . Therefore, piping such as a gas duct that communicates devices installed in the inside and outside spaces of the area is provided through the shielding wall.

  When such nuclear power plants are decommissioned or when periodic inspections are performed, it is necessary to hermetically close the above piping at a desired position in order to ensure airtightness and prevent radiation leakage. In general, there is a mechanism in which the piping can be closed by closing the existing valves in each part of the piping.

  However, at present, no countermeasure is provided for an old nuclear power plant or a case where airtightness in a pipe is required at an unexpected location that cannot be handled by existing valves. Although a method of directly closing the inside of the pipe by accessing from inside the pipe is conceivable, there is a problem of the exposure dose received by the worker. Although it is conceivable to use a remote dismantling device to close the piping, an optimum device having such a function has not been developed at this stage.

  Therefore, in Japanese Patent Application Laid-Open No. H10-260260, the applicant of the present invention has introduced a flexible bag body into the pipe as a pipe cutting method for cutting the pipe communicating with the radiation source, and has a fluid flow into the bag body. A method for closing the inside of a pipe by expanding the pipe has been proposed.

JP 2010-32253 A

  By the way, in the said patent document 1, although the structure which uses water etc. as a fluid for expansion | swelling of a bag body is disclosed, when liquids, such as water, are inject | poured, a bag body deform | transforms by the influence of gravity and piping. It may be difficult to securely seal the inside.

  The present invention has been made in view of the above-described problems of the prior art, and an object thereof is to provide a closing member that can reliably close a pipe penetrating a radiation shielding wall at a desired position.

  A closing member according to the present invention is a closing member that is installed in a pipe that penetrates a radiation shielding wall and expands when a fluid is injected to close the pipe. And each of the bags is provided with an inlet for the fluid.

  According to such a configuration, the inner space of the inflatable closing member is divided into a plurality of parts, and each bag body is provided with a fluid inlet, whereby each bag body is inflated independently. Can do. For this reason, it is possible to suppress as much as possible the occurrence of a problem that the blocking member expands in a distorted state due to the influence of gravity at the time of injection and the piping cannot be completely blocked. In addition, since the internal space is partitioned into a plurality of parts, crushing due to aging weight is reduced, and a stable airtight state can be maintained over a long period of time.

  When at least two of the closing members are provided so that the bags are stacked in the vertical direction in a state where they are installed in the pipe, durability against crushing and distortion due to their own weight can be further improved.

  When the inclusion bag body including the respective bag bodies is provided, the inclusion bag body serves as an outer skin to prevent the damage of each bag body, which is particularly effective for long-term piping closing. In addition, since the rigidity can be borne by the inclusion bag, any shape of the bag can satisfy the required shape, and versatility is improved. Therefore, the inclusion bag body is preferably configured to have a higher strength than the bag body.

  According to the present invention, the internal space of the inflatable closing member is divided into a plurality of parts, and each bag is provided with a fluid inlet, whereby each bag can be independently expanded. . For this reason, it is possible to suppress as much as possible the occurrence of a problem that the blocking member expands in a distorted state due to the influence of gravity at the time of injection and the piping cannot be completely blocked.

FIG. 1 is an explanatory diagram illustrating a configuration example of a nuclear reactor facility provided with piping to be blocked by a blocking member according to an embodiment of the present invention. FIG. 2 is a flowchart illustrating an example of a procedure of a method for closing a shielding wall through pipe using a closing member according to an embodiment of the present invention. FIG. 3 is an explanatory view showing a state in which work equipment is installed in a part of the piping and an opening is formed. FIG. 4 is an explanatory view showing a state in which the closing member is inserted into the pipe through the opening from the state shown in FIG. FIG. 5 is an explanatory view showing a state in which a fluid is introduced into the lower balloon and inflated from the state shown in FIG. FIG. 6 is an explanatory diagram showing a state in which the closing member is completely inflated by allowing a fluid to flow into the upper balloon from the state shown in FIG. FIG. 7 is a perspective view of the closed member according to the embodiment of the present invention in an expanded state. 8 is a view showing the closing member shown in FIG. 7, FIG. 8 (A) is a side view, and FIG. 8 (B) is a front view. FIG. 9 is an explanatory view showing a state in which the closing member shown in FIG. 7 is contracted and rounded.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a closing member according to the present invention will be described in detail with reference to the accompanying drawings by giving preferred embodiments in relation to a closing method for a shielding wall through pipe using this member.

  FIG. 1 is an explanatory diagram illustrating a configuration example of a nuclear reactor facility 14 including a pipe 12a (12b to 12d) to be closed by a closing member 10 (see FIG. 7) according to an embodiment of the present invention.

  As shown in FIG. 1, the nuclear reactor equipment 14 includes a reactor main body 20 having a reactor pressure vessel 16 and a reactor containment vessel 18 surrounding the reactor pressure vessel 16. It is provided and configured in the reactor building 22 made of manufactured or the like. The periphery of the reactor main body 20 is covered by a radiation shielding wall (shielding wall) 24 that constitutes a part of the reactor building 22, and the radiation shielding wall 24 radiates the inside (reactor main body 20 side). A high-activity level radioactively contaminated area is separated from a clean area free from or low in radioactive contamination.

  A plurality (four in FIG. 1) of pipes 12a, 12b, 12c, and 12d pass through the radiation shielding wall 24. Each piping 12a-12d is a gas duct for communicating the reactor main body 20 in a radiation pollution area | region, and the apparatuses 25 and 26 (for example, heat exchanger) in a clean area, for example.

  The closing member (sealing member, airtight member) 10 according to the present embodiment, for example, airtightly connects the pipe 12a penetrating the radiation shielding wall 24 that isolates the radiation-contaminated region from the clean region at a desired position. Effectively used to occlude. In the following, while exemplifying a method (blocking method of the shielding wall through pipe), the piping 12a is closed by the blocking member 10 in the vicinity of the wall surface of the radiation shielding wall 24 (a portion surrounded by a broken circle in FIG. 1). A specific configuration of the closing member 10 will be described.

  FIG. 2 is a flowchart showing an example of the procedure of the blocking method for the shielding wall through pipe using the blocking member 10 according to the embodiment of the present invention. Moreover, FIGS. 3-6 is operation | movement explanatory drawing which shows an example of the obstruction | occlusion procedure of the piping 12a by the obstruction | occlusion method of the shielding wall penetration piping shown in FIG.

  In step S1 in FIG. 2, first, an opening 28 is formed through a part of the pipe 12a, here near the wall surface outside the radiation shielding wall 24 (opposite to the reactor body 20 side) (see FIG. 3). ). For example, when the pipe 12a is a carbon steel having a plate thickness of 22 mm and a diameter of 1800 mm, the opening 28 may be cut into one side of the pipe 12a as a square having a side of about 500 mm.

  Prior to the formation of such an opening 28, work facilities such as a work floor 30, a shielding plate 32, a barrier 34, and a ventilation facility 36 are installed in a place serving as a work area around the site where the opening 28 is formed. . The work floor 30 is laid on the upper surface of the pipe 12 a, and the shielding plate 32 is provided so as to be in close contact with the outer surface of the radiation shielding wall 24. The barrier 34 is a shielding member that surrounds the space outside the opening 28 in order to prevent the gas in the pipe 12 a from leaking outside through the opening 28, and the gas inside the barrier 34 is ventilated by the ventilation facility 36. .

  Subsequently, as shown in FIG. 4, after the closing member 10 in a contracted and rounded (or folded) state is inserted into the pipe 12 a from the opening 28 (step S <b> 2), using a compressor or the like (not shown). Air is pumped into the closing member 10, and the closing member 10 is inflated to some extent and installed at a desired closing position (step S3).

  Here, with reference to FIGS. 7-9, the structural example of the closure member 10 which concerns on this embodiment is demonstrated.

  As shown in FIGS. 7, 8 </ b> A, and 8 </ b> B, the closing member 10 has a shape (for example, a diameter of 1800 mm and an axial length) that matches the shape of the internal space of the pipe 12 a in a fully expanded state. It is a flexible bag-like member manufactured in a 2000 mm cylindrical shape. The closing member 10 is provided with inlets 41a and 41b for inflating (expanding) fluid, and a pair of balloons (bags) 40a and 40b whose inner spaces are independent from each other are stacked in the vertical direction, and the outer periphery thereof is arranged. The reinforcing bag body (included bag body) 44 is included. The reinforcing bag body 44 preferably has a structure having higher strength than the balloons 40a and 40b, for example, pressure resistance performance and shape retention performance, by appropriately selecting the material, shape, and the like.

  More specifically, the closing member 10 has a cylindrical shape in a completely inflated state, and balloons (balloon tubes) 40a and 40b, which are two tube-shaped bag bodies having a semicircular cross section, are moved up and down. By bonding or integrally molding, the internal space is partitioned as a plurality of bag bodies (balloons 40a and 40b), and the outer peripheral surface is included so as to make a round with the reinforcing bag body 44. That is, in the case of this embodiment, the end surfaces on both ends in the axial direction of the balloons 40a and 40b are not included in the reinforcing bag body 44, and only the outer peripheral surfaces of the balloons 40a and 40b are cylindrical reinforcing bag bodies 44. The balloons 40a and 40b and the reinforcing bag 44 are cut off. Of course, the entire surface of the balloons 40a and 40b may be included in the reinforcing bag 44.

  For example, a pair of injection ports 41a of the lower balloon 40a is provided at one end surface of the balloon 40a, and a pair of injection ports 41b of the upper balloon 40b is provided at the top of the outer peripheral surface of the balloon 40b, for example. Injection hoses 42a and 42b are connected to the injection ports 41a and 41b, respectively (see FIGS. 4 to 6).

  As shown in FIG. 9, the closing member 10 can be contracted and compactly rolled in a state where a fluid for expansion (expansion) (for example, mortar) is not injected therein. Therefore, in the step S2, the closed blocking member 10 in a rolled state can be easily inserted into the pipe 12a from the small opening 28. In step S3, air is pumped into the closing member 10 in a compactly folded state using the injection hoses 42a and 42b for fluid injection, so that the closing member 10 is expanded to some extent in the pipe 12a. It is a process for installing in a predetermined position and making it possible to smoothly carry out fluid (mortar) injection in the next process. In other words, it may be difficult to smoothly inflate the closing member 10 even if the expansion fluid is injected in a state in which the closing member 10 is folded several times. By sending air into the member 10, the closed member 10 is removed from the rounded state and is in a state of extending flatly to prepare for the next fluid inflow.

The material of the closing member 10 is not particularly limited, but as the balloons 40a and 40b, urethane, for example, thermoplastic polyurethane (for example, polyether type) which is a high molecular compound having a urethane bond (—NHCOO—) in the molecule. A softening temperature of 150 ° C., a flash point of 240 ° C., and a specific gravity of about 1.1) may be used, and the composition is, for example, (—O—R′—OCO—NH—R—NHCO—) n. Here, R ′ is a polyether (ether bond —O—). On the other hand, the reinforcing bag 44 is represented by a chemical formula of ultra high molecular weight polyethylene (ultra high strength polyethylene fiber), for example, (CH ₂ —CH ₂ ) n, and is made of carbon (C) and hydrogen (H). (Eg, Dyneema (registered trademark), softening temperature 130 ° C., flash point 400 ° C., specific gravity about 0.97) may be used.

  Needless to say, the shape of the closing member 10 may be appropriately designed in accordance with the shape of the internal space of the pipe 12a to be closed. In short, it can be easily inserted into the pipe 12a from the opening 28 by contracting. In addition, any shape may be used as long as it can be surely expanded in the pipe 12a, tightly adhered to the inner surface of the pipe 12a, and hermetically closed so as to block the gas flow in the pipe 12a.

  Returning to FIG. 2, in step S4, mortar, which is an expansion fluid, is injected into the closing member 10 disposed at a predetermined position in the pipe 12a by using a mortar pump and injection hoses 42a and 42b (not shown). (See FIGS. 5 and 6). As a result, the closing member 10 is completely inflated, and is tightly contacted with the entire inner circumference of the pipe 12a, thereby closing the inside of the pipe 12a in an airtight state (see FIG. 6).

  In the present embodiment, as described above, the closing member 10 having the upper and lower two-stage structure using the two balloons 40a and 40b is used. First, one injection hose 42a is communicated with the injection port 41a. Mortar is injected into the lower balloon tube 40a (see FIG. 5), and then the other injection hose 42b is communicated with the injection port 41b to inject mortar into the upper balloon tube 40b (see FIG. 6). ). When the occluding member 10 is configured in two upper and lower layers and mortar is injected sequentially from the lower balloon 40a in this way, the occluding member 10 expands in a distorted state due to the influence of gravity at the time of injection, and the inside of the pipe 12a is completely removed. It is possible to suppress as much as possible the occurrence of a problem that makes it impossible to block, and the crushed due to its own weight over time is reduced. Of course, the internal space of the closing member 10 may be divided into three or more layers. In this case, three or more balloons may be provided in multiple layers in the vertical direction.

  Since the mortar injected into the closing member 10 condenses, the inside of the pipe 12a is completely closed by the closing member 10 whose inside is solid, so in the subsequent step S5, the injection hoses 42a and 42b are removed. The opening 28 is completely closed. What is necessary is just to join the board | plate material etc. of the same material as the piping 12a by welding etc., for the opening part 28 to close. Thereby, the closing member 10 in which the mortar is condensed inside and solidified is installed in the pipe 12a in a state where the pipe passage is airtightly closed.

  Therefore, in step S6, the work equipment used for insertion / expansion of the closing member 10, for example, the work floor 30, the shielding plate 32, the barrier 34, the ventilation equipment 36, and the like are removed, and then in step S7, the nuclear reactor is removed. In a state in which leakage of radioactivity is prevented from occurring from the main body 20 via the pipe 12a, other operations such as the operation of decommissioning the nuclear reactor facility 14 and the periodic inspection of predetermined equipment can be performed.

  As described above, the closing member 10 according to the present embodiment is installed in the pipe 12a (12b to 12d) penetrating the radiation shielding wall 24, and is expanded when the fluid is injected to close the pipe 12a. The internal space is partitioned as a plurality of balloons 40a and 40b, and the fluid inlets 41a and 41b are provided in the balloons 40a and 40b, respectively.

  Thus, in the closing member 10, the inside of the inflatable closing member 10 is divided into a plurality of layers, so that the closing member 10 expands in a distorted state due to the influence of gravity at the time of injection, and the inside of the pipe 12 a is expanded. It is possible to suppress as much as possible the occurrence of problems that cannot be completely blocked. In addition, since the interior is partitioned into a plurality of layers, it is possible to reduce crushing due to its own weight over time and maintain a stable airtight state over a long period of time. For this reason, since the opening part 28 is formed in the vicinity of the site | part which wants to obstruct | occlude the piping 12a, and the inside of the piping 12a can be obstruct | occluded and airtight only by inserting the obstruction | occlusion member 10 and expanding it, Even in an unexpected location that cannot be handled by an existing valve, the pipe 12a penetrating the radiation shielding wall 24 can be easily closed at a desired location, for example, It is possible to prevent the leakage of radiation from the pipe 12a at the time of another work such as a periodic inspection, and to carry out the work smoothly.

  In this case, when at least two closing members 10 are provided so that the balloons 40a and 40b are stacked in the vertical direction in the state where they are installed in the pipe 12a, the durability against crushing and distortion due to their own weight is further improved. Can do.

  In the closing member 10, it is also effective to provide a reinforcing bag body 44 that collectively includes the balloons 40a and 40b arranged in a stacked manner. As a result, the reinforcing bag body 44 becomes an outer skin to prevent the balloons 40a and 40b from being damaged, which is particularly effective for long-term closing of the pipe 12a. In addition, since the rigidity can be borne by the reinforcing bag 44, the required shape can be satisfied regardless of the shape of the balloons 40a and 40b, and versatility is improved. For this reason, it is preferable that the reinforcing bag body 44 is configured to have higher strength than the balloons 40a and 40b.

  Further, by using mortar as the fluid for expanding the closing member 10, since the density of the mortar is higher than that of water, it is possible to obtain a high radiation shielding effect in the pipe 12a and to reduce the exposure dose of the worker. Can do. Moreover, since the mortar condenses and solidifies after the injection, the inside of the pipe 12a can be stably closed, and even if the closing member 10 is broken thereafter, the airtightness is not affected, and the pipe 12a is kept for a long time. It can be stably blocked over the period.

  In addition, it is also effective to use a weight mortar instead of a normal mortar as the fluid for expanding the closing member 10. By using a weight mortar having a density higher than that of the mortar, the radiation shielding effect in the pipe 12a can be further improved.

  It is also effective to use water as the fluid for expanding the closing member 10. Water is easier to handle than mortar and can reduce costs, while at the same time providing a sufficient radiation shielding effect in the pipe 12a. If water is used, after the separate operation in step S7 is completed and the closing request for the pipe 12a is released, the water in the closing member 10 can be absorbed and removed so that the closing member 10 can be easily removed. For example, it is particularly effective when it is desired to temporarily close the inside of the pipe 12a as in a periodic inspection. In this case, the complete closing of the opening 28 in step S5 may be kept at the primary closing (temporary closing).

  It is also effective to freeze water that is a fluid for expansion in the closing member 10. Then, since the inside of the closing member 10 can be solidified, compared to the case where water is stored in the closing member 10 as it is, the ease of handling and the cost reduction effect are maintained, and in a more stable state. The pipe 12a can be airtightly closed. At this time, after the completion of another operation in step S7 and the request for closing the pipe 12a being canceled, the ice in the closing member 10 can be removed by absorbing water and the closing member 10 can be easily removed. Therefore, it is particularly effective when, for example, it is desired to temporarily close the inside of the pipe 12a as in a periodic inspection.

  It should be noted that the present invention is not limited to the above-described embodiment, and it is needless to say that the present invention can be freely changed without departing from the gist of the present invention.

  For example, a fluid other than the mortar, weight mortar, and water may be used as the fluid for expanding the closing member 10, but a material having a certain level of radiation shielding performance is preferably used. It is more preferable to use a material that is in the form of a solid and can be solidified after injection.

DESCRIPTION OF SYMBOLS 10 Closure member 12a-12d Piping 20 Reactor main body 24 Radiation shielding wall 28 Opening part 40a, 40b Balloon 41a, 41b Inlet 42a, 42b Injection hose 44 Reinforcing bag

Claims (4)

A blocking member that is installed in a pipe that penetrates the radiation shielding wall and expands when the fluid is injected to close the pipe.
An occlusion member characterized in that an internal space is partitioned as a plurality of bags and an inlet for the fluid is provided in each bag. The closure member according to claim 1,
The closure member is provided with at least two such closure members so that the bags are stacked in the vertical direction in a state of being installed in the pipe. The closure member according to claim 1 or 2,
An occlusion member provided with an inclusion bag that collectively includes each bag. The closure member according to claim 3,
The closure member characterized in that the inclusion bag body has higher strength than the bag body.

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