JP2015184226A - Radiation shielding body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radiation shielding body that allows in-reactor apparatuses in a boiling water type nuclear reactor plant to be easily taken out.SOLUTION: A radiation shielding body comprises a plurality of mutually connected radiation shielding bags 101 fixed to a support member 107, and each of the plurality of radiation bags 101 internally includes a contractable member 102 that connects one side of a vertical direction of the radiation shielding bag 101 or lateral direction thereof to other side thereof facing the one side. Each of the plurality of radiation bags 101 is configured to be inflated when a liquid having an effect of shielding radiation is injected, and be contracted while being guided by the contractable member 102 when the liquid is discharged.

Description

  The present invention relates to a radiation shield, and more particularly, to a bag-shaped radiation shield used when carrying out in-core equipment and fuel in a boiling water nuclear power plant.

  As a background technique related to this technique, there is a technique described in Patent Document 1. Patent Document 1 discloses a reactor that has been activated in a large-scale construction in which a reactor pressure vessel used for nuclear power generation is moved from its installation location for replacement work or the like. A radiation shielding method for shielding radiation such as gamma rays from the internal structure is described. In this method, before the reactor pressure vessel is carried out, a shielding material that has fluidity at the time of filling and solidifies with the passage of time is filled in the bottom space in the reactor pressure vessel, and radiation at the time of carrying out the reactor pressure vessel is emitted. Shielding is described.

  Non-Patent Document 1 describes a method for taking out fuel debris in a boiling water nuclear power plant. In this Non-Patent Document 1, in order to fill the inside of the reactor containment vessel and remove the fuel debris, a leakage location investigation inside the reactor containment vessel is conducted in advance to repair the specified leakage location. A method is described in which the water is stopped, and then the inside of the reactor containment vessel is filled with water, the core is submerged, and the fuel debris is carried out after conducting an investigation or the like.

  Patent Document 2 describes a radiation shield that uses a shielding liquid in a bag.

JP 2000-155195 A Japanese Patent Laid-Open No. 9-230090

"Medium-to-long-term roadmap for decommissioning of TEPCO's Fukushima Daiichi Nuclear Power Station Units 1 to 4 (summary version)", [online], December 16, 2011, Ministry of Economy, Trade and Industry, [ Search on February 17, 2014], Internet <http://www.meti.go.jp/earthquake/nuclear/pdf/111221_01a.pdf>

  In large-scale construction where the reactor pressure vessel is moved from its installation location, the top cover of the reactor pressure vessel provided in the reactor pressure vessel, the RPV heat insulating material, the air provided inside the reactor pressure vessel It may be necessary to carry out the water separator and steam dryer separately. When carrying out the steam-water separator and steam dryer provided inside the reactor pressure vessel individually, as shown in Non-Patent Document 1, the inside of the reactor containment vessel can be filled with water, It is necessary to take out after giving a radiation shielding effect by performing water filling in advance, but if there is a water leaking place inside the reactor containment vessel, it takes a lot of time to prepare for water filling, There is room for further improvement in this technology.

  In order to efficiently carry out the in-reactor equipment in the boiling water reactor plant, a method using a radiation shield that is easy to install as described in Patent Document 2 is also conceivable. However, conventional radiation shields such as the radiation shield described in Patent Document 2 are not sufficient for installation locations and work processes required for such work, and are sufficient for workers and the surrounding environment. While providing a safe working environment, it is not always possible to work efficiently.

  An object of this invention is to provide the radiation shield which enables carrying out of the equipment in a reactor in a boiling water reactor plant efficiently.

  The radiation shield according to the present invention has the following features. A plurality of radiation shielding bags connected to each other and fixed to a support member, each of the plurality of radiation shielding bags includes one side in the vertical direction or the lateral direction of the radiation shielding bag and the other side facing the one side. And a member that can be expanded and contracted is provided inside. Each of the plurality of radiation shielding bags expands when a liquid having a radiation shielding effect is injected, and contracts by being retracted by the extendable member when the liquid is discharged.

  When the radiation shield according to the present invention is used, the in-core equipment in the boiling water reactor plant can be efficiently carried out.

The figure showing the outline | summary of a boiling water nuclear power plant. FIG. 3 is a diagram illustrating a radiation shield according to the first embodiment. The front view at the time of liquid injection of the shielding bag which comprises the radiation shielding body by Example 1. FIG. The front view at the time of draining of the shielding bag which comprises the radiation shielding body by Example 1. FIG. The front view at the time of liquid injection of the shielding bag which comprises the radiation shield of another structure by Example 1. FIG. The front view at the time of the drainage of the shielding bag which comprises the radiation shield of another structure by Example 1. FIG. FIG. 6 is a top view of a radiation shield according to Embodiment 2. The front view which showed a mode that each part of the radiation shielding body by Example 2 was replaced and installed. The front view at the time of liquid injection of the shielding bag which comprises the radiation shielding body by Example 2. FIG. The front view at the time of the drainage of the shielding bag which comprises the radiation shielding body by Example 2. FIG. The figure explaining the procedure which replaces a shield plug with a radiation shield. The figure explaining the procedure which replaces a shield plug with a radiation shield. The figure explaining the procedure which replaces a shield plug with a radiation shield. The figure explaining the procedure which replaces a shield plug with a radiation shield. The figure explaining the procedure which replaces a shield plug with a radiation shield. The figure explaining the procedure which replaces a shield plug with a radiation shield. The figure explaining the procedure which replaces a shield plug with a radiation shield. The figure explaining the procedure which replaces a shield plug with a radiation shield. The figure explaining the procedure which replaces a shield plug with a radiation shield. The figure which shows the state which expand | deployed the radiation shield by Example 3 on the reactor well from DSP. The figure explaining the procedure which expand | deploys a radiation shield on a reactor well from DSP. The figure explaining the procedure which expand | deploys a radiation shield on a reactor well from DSP. The figure explaining the procedure which expand | deploys a radiation shield on a reactor well from DSP. The figure explaining the procedure which expand | deploys a radiation shield on a reactor well from DSP. The figure explaining the procedure which expand | deploys a radiation shield on a reactor well from DSP. The figure explaining the procedure which expand | deploys a radiation shield on a reactor well from DSP. The front view at the time of the drainage of the shielding bag which comprises the radiation shielding body by Example 4. FIG. The front view at the time of liquid injection of the shielding bag which comprises the radiation shielding body by Example 4. FIG. The figure explaining the procedure which replaces a shield plug with a radiation shield in Example 4. FIG. The figure explaining the procedure which replaces a shield plug with a radiation shield in Example 4. FIG. The figure explaining the procedure which replaces a shield plug with a radiation shield in Example 4. FIG. The figure explaining the procedure which replaces a shield plug with a radiation shield in Example 4. FIG. In Example 4, the top view of a reactor well and DSP. The figure explaining the raw material of the shielding bag which comprises the radiation shielding body by the Example of this invention. The figure explaining another raw material of the shielding bag which comprises the radiation shielding body by the Example of this invention.

  The radiation shield according to the present invention is used particularly when carrying out in-core equipment and fuel in a boiling water nuclear power plant. The radiation shield according to the present invention includes a plurality of radiation shielding bags (hereinafter also simply referred to as “shielding bags”) that are connected to each other and can be expanded and contracted vertically or laterally by liquid injection and drainage. Each of the shielding bags is fixedly arranged on the support member and connected to each other. Each of the shielding bags can contain a liquid for shielding, expands due to the injection pressure when injected, shrinks when discharged, and can expand or contract in the vertical direction or the horizontal direction. Each of the shielding bags includes a member that can be expanded and contracted by connecting one side in the vertical direction or the lateral direction of the shielding bag and the other side facing the one side. The extendable member is constituted by, for example, a bar-shaped member or a combination of a winding spring and a linear member, and guides the shielding bag to shrink in the vertical direction or the horizontal direction. For example, a cylinder or a spring can be used as the rod-shaped member constituting the extendable member, and for example, a tension wire can be used as the linear member.

  Each of the shielding bags includes a shape maintaining member on the outer surface. The shape maintaining member is made of, for example, a metal wire or plate, or fiber reinforced plastic (FRP), maintains the shape of the shielding bag in a direction other than the expansion direction, and the shielding bag expands in a direction other than the expansion direction. Suppress. The radiation shield according to the present invention can easily install and remove the radiation shield by expanding and contracting the shielding bag in the vertical direction or the horizontal direction, and can efficiently carry out the in-core equipment in the boiling water reactor plant. It can be carried out.

As the liquid contained in the shielding bag, a liquid having a radiation shielding effect such as water can be used. In addition to water, for example, a material having fluidity at room temperature and having a specific gravity of at least concrete (2.15 g / cm ³ ) or more can be used in order to ensure sufficient shielding against radiation. For example, a material in which barium sulfate is dispersed in a solution is used as a medical material and is not harmful to the human body, becomes liquid at room temperature, and has a specific gravity of about 4.5 g / cm ³ . Suitable as a shielding material.

  The liquid inside the shielding bag may be discharged into the reactor containment vessel (PCV). By discharging the liquid from the shielding bag, it is possible to reduce the weight of the equipment to be carried out of the furnace, thereby improving work efficiency.

  Hereinafter, radiation shields according to embodiments of the present invention will be described. In the following description, the same elements are denoted by the same reference numerals, and repeated description thereof may be omitted.

  First, a schematic structure of a boiling water nuclear power plant in which a radiation shield according to an embodiment of the present invention is used will be described with reference to FIG.

  FIG. 1 is a diagram showing an outline of a boiling water nuclear power plant. The boiling water nuclear power plant 1 includes a nuclear reactor 2 and a reactor containment vessel (hereinafter referred to as PCV 3). The PCV 3 is installed in the reactor building 4 and is sealed with a PCV upper lid 5 attached to the upper end. The PCV 3 includes a dry well 6 formed inside and a pressure suppression chamber 7 in which a pressure suppression pool filled with cooling water is formed. One end of the vent passage 8 connected to the dry well 6 is immersed in the cooling water of the pressure suppression pool in the pressure suppression chamber 7. A shield plug 9, which is a radiation shielding body divided into a plurality of parts, is disposed directly above the PCV upper lid 5, and these shield plugs 9 are installed on the operation floor of the reactor building 4.

  A nuclear reactor 2 includes a reactor pressure vessel (hereinafter referred to as RPV 11) configured with an RPV top cover 10, a core 12 loaded with a plurality of fuel assemblies containing nuclear fuel materials, a steam separator 13 and steam drying. A container 14 is provided. The core 12, the steam separator 13 and the steam dryer 14 are arranged in the RPV 11. A core shroud 15 installed in the RPV 11 surrounds the core 12. Each fuel assembly 16 loaded in the core 12 has a lower end supported by the core support plate 17 and an upper end held by the upper lattice plate 18. The steam separator 13 is disposed above the upper lattice plate 18 located at the upper end of the core 12. The steam dryer 14 is disposed above the steam / water separator 13.

  A plurality of control rod guide tubes 19 are arranged below the core 12, and the lower portion of the core 12 is constituted by a plurality of control rod guide tubes 19 and a shroud support cylinder. Control rods 20 that are taken in and out between the fuel assemblies 16 in the core 12 and control the reactor power are disposed in the control rod guide tubes 19. A plurality of control rod drive mechanism housings 21 are attached to the lower mirror 22 of the RPV 11. A control rod drive mechanism (not shown) is installed in each control rod drive mechanism housing 21 and connected to the control rod 20 in the control rod guide tube 19. The steam / water separator 13, the steam dryer 14, the core shroud 15, the upper lattice plate 18, the core support plate 17, the support cylinder, the control rod guide tube 19, and the core shroud lower shell installed in the RPV 11 are in-core structure. It is a thing.

  The RPV 11 is installed on a cylindrical pedestal 24 provided on a concrete mat 23 provided at the bottom of the PCV 3. A cylindrical γ-ray shield 25 is installed at the upper end of the pedestal 24 and surrounds the RPV 11.

  The reactor building 4 includes a reactor separator 26 and a separator / separator storage pool (hereinafter referred to as “DSP” 27) and a spent fuel storage pool (hereinafter referred to as “SFP”) that temporarily stores used fuel. "28") is provided. The DSP 27 is used as a place for temporarily placing in-furnace structures such as the steam separator 13 and the steam dryer 14 during periodic inspection. Further, an RPV heat insulating material is provided on the upper portion of the RPV upper lid 10.

  As a preparatory work before carrying out the work of carrying out the in-reactor equipment and the fuel, a work house, which is an area for installing various devices, is installed on the operation floor of the reactor. In this embodiment, a radiation shield installed in the work house will be described.

  The radiation shield according to this embodiment will be described with reference to FIGS. 2, 3A, and 3B. FIG. 2 is a diagram showing the radiation shield 100 according to the present embodiment. An upper view of FIG. 2 is a top view of the radiation shield 100, and a lower view is a front view of the radiation shield 100 during drainage. FIG. 3A is a front view of the shielding bag 101 constituting the radiation shield 100 at the time of liquid injection, and FIG. 3B is a front view of the shielding bag 101 at the time of drainage.

  The radiation shield 100 according to the present embodiment includes a plurality of shielding bags 101 connected to each other. Each of the shielding bags 101 is directly fixed to the support member 107 with a bolt or the like. Each of the shielding bags 101 can contain a liquid, expands upward due to the injection pressure when injected, contracts downward when discharged, and can expand and contract vertically. Each of the shielding bags 101 has a rod-like member 102 that can be expanded and contracted by connecting the upper and lower portions of the shielding bag 101, a supply / drainage pipe 104 that can be expanded and contracted for injection and drainage, and a submersible pump 105. Prepare. The rod-shaped member 102 is configured by, for example, a cylinder or a spring and can be expanded and contracted, and guides the shielding bag to expand and contract in the vertical direction. The supply / drainage pipe 104 is formed by spiraling a tubular member made of resin, and can expand and contract as a whole. As the resin used for the supply / drain pipe 104, for example, polyurethane resin and polyamide resin (nylon) can be used in consideration of radiation resistance. Each of the shielding bags 101 includes a shape maintaining member 103 on the outer surface (not including the upper surface and the lower surface). The shape maintaining member 103 is made of, for example, a metal wire or plate or fiber reinforced plastic (FRP), maintains the shape of the shielding bag in the lateral direction, and suppresses the expansion of the shielding bag in the lateral direction.

  The radiation shield 100 is placed on a support member 107, and an upper lid 106 is installed on the top. The plurality of shielding bags 101 are connected to each other with a gap 108 provided in part. This gap is for passing the wire rope of the lifting balance 109.

  As shown in FIG. 3A, the supply / drainage pipe 104 is connected to an external pump (not shown), and the liquid pumped by the external pump flows. When the liquid is injected from the supply / drainage pipe 104, the shielding bag 101 expands due to the injection pressure. At this time, the expansion of the shielding bag 101 in the lateral direction is suppressed by the shape maintaining member 103, and the shielding bag 101 is guided by the rod-shaped member 102 to expand upward. The radiation shield 100 provides a radiation shielding effect.

  As shown in FIG. 3B, when the liquid inside the shielding bag 101 is pumped by the submersible pump 105 and discharged through the supply / drainage pipe 104, the inner pressure of the shielding bag 101 decreases and is guided by the rod-shaped member 102. Scale down. Although the shielding bag 101 has a fold, since the rod-like member 102 is composed of, for example, a cylinder or a spring, the shielding bag 101 can be forcibly reduced according to the drainage. By reducing the shielding bag 101 downward, the gap between the radiation shield 100 and the overhead crane can be narrowed when the in-furnace equipment is lifted, and the lifting height can be secured as much as possible.

  4A and 4B, another configuration of the radiation shield according to the present embodiment will be described. 4A is a front view of the shielding bag 151 that constitutes the radiation shield 100 when liquid is injected, and FIG. 4B is a front view of the shielding bag 151 that is drained. The shielding bag 151 does not include the supply / drain liquid pipe 104 and the submersible pump 105 inside, and includes the supply / drain liquid hole 110 on the lower surface. The support member 107 includes a manifold 111 connected to the supply / drainage hole 110 of the shielding bag 151. Further, a drainage pump 112 connected to the manifold 111 is installed at the bottom of the shielding bag 151, and a supply / drainage pipe 113 is connected to the drainage pump 112. An external pump (not shown) is connected to the supply / drainage pipe 113.

  As shown in FIG. 4A, when liquid is injected into the manifold 111 through the supply / drain pipe 113 by an external pump (not shown), the shielding bag 151 is expanded from the manifold 111 and expands upward due to the injection pressure. .

  As shown in FIG. 4B, when the drainage pump 112 drains the liquid in the manifold 111 to the supply / drainage pipe 113, the liquid inside the shielding bag 151 is discharged through the manifold 111, and the inner pressure of the shielding bag 151 decreases. Then, it is guided by the rod-shaped member 102 and contracts downward.

  As shown in FIGS. 4A and 4B, the structure of the shielding bag 151 can be simplified and the weight of the shielding bag 151 can be reduced if the supply / drain pipe 104 and the submersible pump 105 are not provided inside the shielding bag 151. There is an effect.

  In the work of carrying out the reactor equipment and the fuel, the shield plug 9 is carried out after the work house is installed on the operation floor of the reactor. In this embodiment, a radiation shield used for carrying out the shield plug 9 and replacing the shield plug 9 will be described.

  FIG. 5A is a top view of the radiation shield 200 according to the present embodiment. The radiation shield 200 according to the present embodiment includes three parts: a first shield 200A, a second shield 200B, and a third shield 200C. Each of the first shield 200A, the second shield 200B, and the third shield 200C includes a plurality of shielding bags 201. When viewed from above, the first shield 200A and the third shield 200B have a shape surrounded by a circular arc and a straight line, and the second shield 200C has a quadrangular shape with two sides formed by a circular arc, and the first shield 200A. When the second shield 200B and the third shield 200C are combined, a circular shape is obtained. The first shield 200A, the second shield 200B, and the third shield 200C use a flat plate corresponding to each shape as the support member 207, and are fixed to the lower surface of the flat plate with a hanging tool.

  FIG. 5B is a front view showing a state in which each part of the radiation shield 200 is replaced with the shield plug 9 after the shield plug 9 is carried out. The shield plug 9 is divided into three parts, a right side part, a central part, and a left side part, toward the front of the PCV, and each part is pulled up to the upper surface of the reactor well 26 by a shield plug pulling jack and is carried out. . The radiation shield 200 is installed at the position of the shield plug 9 pulled up. The first shield 200A is positioned at the right side of the shield plug 9, the second shield 200B is positioned at the left side of the shield plug 9, and the third shield 200C is positioned at the center of the shield plug 9. , Each installed. When installing the radiation shield 200, a retractor provided in a shield plug pulling jack is used.

  FIG. 6A is a front view of the shielding bag 201 constituting the radiation shield 200 at the time of liquid injection, and FIG. 6B is a front view of the shielding bag 201 at the time of draining. The shielding bag 201 includes a shape maintaining member 103, a supply / drainage pipe 104, and a submersible pump 105, similar to the shielding bag 101 shown in FIGS. 3A and 3B. The radiation shield 200 is provided with an upper lid 106 at the top. A winding spring 202 is installed on the upper lid 106, and a tension wire 205 that is a linear member is connected to the winding spring 202. The tension wire 205 has one end connected to the winding spring 202 and the other end connected to the lower part of the shielding bag 201. The winding spring 202 and the tension wire 205 constitute an extendable member that connects one side of the shielding bag 201 and the other side facing the one side, and guides the shielding bag 201 to shrink. In addition, the radiation shield 200 is suspended from the suspension 203 provided on the support member 207 by a protrusion provided on the upper surface of the upper lid 106. The support member 207 has a seating ring 204 and is installed via the seating ring 204 at a position where the shield plug 9 is installed, that is, at the circumference (outer peripheral surface) of the reactor well 26.

  As shown in FIG. 6A, the supply / drainage pipe 104 is connected to an external pump (not shown), and the liquid pumped by the external pump flows. When the liquid is injected from the supply / drainage pipe 104, the shielding bag 201 expands due to the injection pressure. At this time, the expansion of the shielding bag 201 in the lateral direction is suppressed by the shape maintaining member 103 and expands downward due to the weight of the liquid. With this radiation shield 200, even if the shield plug 9 is removed, the radiation shielding effect can be obtained.

  As shown in FIG. 6B, when the liquid inside the shielding bag 201 is pumped by the submersible pump 105 and discharged through the supply / drain liquid pipe 104, the inner pressure of the shielding bag 201 decreases. Then, the shielding bag 201 is forcibly contracted upward by the action of the elastic force of the winding spring 202 in accordance with the reduction in the weight of the liquid due to the drainage. The tension wire 205 pulls up the lower part of the shielding bag 201 and guides the shielding bag 201 to shrink upward. The spring constant of the winding spring 202 is determined according to the weight of the liquid injected into the shielding bag 201.

  A procedure for replacing the shield plug 9 with the radiation shield 200 will be described with reference to FIGS. 7A to 7I. For installation of the radiation shield 200 (the first shield 200A, the second shield 200B, and the third shield 200C), a retracting device provided in a shield plug pulling jack is used.

  As shown in FIG. 7A, after the right side portion 206A of the shield plug 9 is pulled up to the upper surface of the reactor well 26 by a shield plug pulling jack (not shown), the first shield 200A of the radiation shield 200 is pulled up. 9 is inserted at the position where the right side portion 206A is located.

  Next, as shown in FIG. 7B, the first shield 200 </ b> A is seated on the position (the outer peripheral surface of the reactor well 26) where the right side portion 206 </ b> A of the shield plug 9 has been installed.

  Next, as shown in FIG. 7C, liquid is injected into the first shield 200A, the first shield 200A is expanded downward, and shielding by the first shield 200A is performed. Thereby, even if the right side portion 206A of the shield plug 9 is removed, the radiation shielding effect can be obtained.

  Next, as shown in FIG. 7D, the left side portion 206B of the shield plug 9 is pulled up to the upper surface of the reactor well 26 by a shield plug pulling jack (not shown), and then the second shield 200B of the radiation shield 200 is pulled up. The shield plug 9 is inserted into the left side portion 206B.

  Next, as shown in FIG. 7E, the second shield 200B is seated at the position (the outer peripheral surface of the reactor well 26) where the left side portion 206B of the shield plug 9 was installed.

  Next, as shown in FIG. 7F, liquid is injected into the second shield 200B, the second shield 200B is expanded downward, and shielding by the second shield 200B is performed. Thereby, even if the left side portion 206B of the shield plug 9 is removed, a radiation shielding effect can be obtained.

  Next, as shown in FIG. 7G, the central portion 206C of the shield plug 9 is pulled up to the upper surface of the reactor well 26 by a shield plug pulling jack (not shown), and then the third shield 200C of the radiation shield 200 is pulled up. The shield plug 9 is inserted into the center 206C at a position.

  Next, as shown in FIG. 7H, the third shield 200C is seated on the position (the outer peripheral surface of the reactor well 26) where the central portion 206C of the shield plug 9 was installed.

  Next, as shown in FIG. 7I, liquid is injected into the inside of the third shield 200C, the third shield 200C is expanded downward, and shielding by the third shield 200C is performed. Thereby, even if the center part 206C of the shield plug 9 is removed, the radiation shielding effect can be obtained.

  Even if all the shield plugs 9 are removed by the above-described procedure described with reference to FIGS. 7A to 7I, they are shielded by the radiation shield 200 (the first shield 200 </ b> A, the second shield 200 </ b> B, and the third shield 200 </ b> C). An effect is obtained.

  In the present embodiment, a radiation shield used for carrying out the PCV upper lid 5 will be described. The radiation shield according to the present embodiment is a deployable radiation shield developed from the DSP 27 onto the reactor well 26.

  FIG. 8 is a view showing a state in which the radiation shield 300 according to the present embodiment is deployed from the DSP 27 onto the reactor well 26. The upper view of FIG. 8 is a top view, and the lower view is a front view. The radiation shield 300 according to the present embodiment includes three parts, a first shield 200A, a second shield 200B, and a third shield 200C, like the radiation shield 200 according to the present embodiment according to the second embodiment. . The DSP 27 is provided with an auxiliary house as a work area, and the radiation shield 300 is installed in the auxiliary house. The first shield 200A, the second shield 200B, and the third shield 200C are inserted into the reactor well 26 from the auxiliary house using a slide mechanism 301 such as a rail, and liquid is injected into the shield bag 201. The The radiation shield 300 can shield the radiation from the inside of the nuclear reactor 2 by the expansion of the shielding bag 201 by the liquid injection.

  In the radiation shield 300 according to the present embodiment, each of the shielding bags 201 is directly fixed to the lower surface of the support member 304 with a bolt or the like. Further, as shown in FIG. 8, the radiation shield 300 according to the present embodiment includes a link arm 302 that is a link member, and an extrusion cylinder 303. The link arm 302 is provided on the upper part of the shielding bag 201, and the extrusion cylinder 303 is provided on the support member 304 that fixes the shielding bag 201. The pushing cylinder 303 applies a pushing force to the link arm 302 with the support member 304 as a starting point.

  The link arm 302 is for finely adjusting the gaps between the first shield 200A, the second shield 200B, the third shield 200C, and the reactor well 26, and a plurality of plate-like members are provided. It is configured to be axially connected to each other (for example, a plurality of plate-like members are configured to be connected in a pantograph shape). As each plate-like member rotates about the axis, the link arm 302 can expand and contract as a whole. The shielding bag 201 of the first shielding body 200A, the second shielding body 200B, and the third shielding body 200C expands somewhat in addition to the expansion / contraction direction (downward) due to the liquid injection. The link arm 302 uses this expansion, and expands in accordance with the change in the width direction (lateral direction) of the shielding bag 201 by the pressure when the shielding bag 201 is expanded. The link arm 302 extends to bring the shielding bags 201 of the first shielding body 200A, the second shielding body 200B, and the third shielding body 200C into close contact with each other, or the first shielding body 200A and the second shielding body. 200B and the third shield 200C are brought into close contact with each other, or the first shield 200A, the second shield 200B, and the third shield 200C are brought into close contact with the reactor well 26.

  A procedure for deploying the radiation shield 300 from the DSP 27 onto the reactor well 26 will be described with reference to FIGS. 9A to 9F. 9A to 9F, the upper diagram is a top view of the reactor well 26 and the DSP 27, and the lower diagram is a front view.

  As shown in FIG. 9A, first, the radiation shield 300 (first shield 200A, second shield 200B, and third shield 200C) is installed on the DSP 27. In order to improve work efficiency, the second shield 200B is installed below the first shield 200A, and the third shield 200C is installed below the second shield 200B.

  Next, as shown in FIG. 9B, the first shield 200 </ b> A is moved to the reactor well 26 by the pushing cylinder 303. The moved first shield 200 </ b> A is located at the center of the reactor well 26. After the movement of the first shield 200A, the second shield 200B is lifted by a lift to move the first shield 200A to the position where the first shield 200A is located, and the third shield 200C is lifted by a lift, and the second shield 200B. Move to the position where there was.

  Next, as shown in FIG. 9C, the first shield 200 </ b> A is moved to one end side of the reactor well 26 by the pushing cylinder 303.

  Next, as shown in FIG. 9D, similarly to the first shield 200 </ b> A, the second shield 200 </ b> B is moved to the reactor well 26 by the push-out cylinder 303 and moved to the other end side of the reactor well 26. After the movement of the second shield 200B, the third shield 200C is lifted and moved to the position where the first shield 200A was originally located.

  Next, as shown in FIG. 9E, the third shield 200 </ b> C is moved to the reactor well 26 by the push-out cylinder 303. The third shield 200C is located between the first shield 200A and the second shield 200B.

  Next, as shown in FIG. 9F, the first shielding body 200A, the second shielding body 200B, and the third shielding body 200C are respectively poured into the shielding bags 201, and the first shielding body 200A and the second shielding body 200B. , And the third shield 200C is expanded downward, and shielding by the radiation shield 300 is performed. The first shield 200A, the second shield 200B, and the third shield 200C are brought into close contact with each other by the link arm 302. Further, the first shield 200 </ b> A, the second shield 200 </ b> B, the third shield 200 </ b> C, and the reactor well 26 are also brought into close contact with each other by the link arm 302.

  Thereby, when carrying out the PCV upper cover 5, the radiation from the inside of the nuclear reactor 2 can be shielded. The liquid inside the shielding bag 201 can be discharged by being pumped by the submersible pump 105 as described in the second embodiment. The shielding bag 201 reduced by discharging the liquid is pulled back to the auxiliary house in the DSP 27 by using the slide mechanism 301.

  In the above embodiment, the radiation shield that expands and contracts in the vertical direction has been described. In this embodiment, a sliding radiation shield 400 that expands and contracts in the horizontal direction (one direction in the horizontal direction) will be described. The radiation shield 400 according to the present embodiment can be used for the unloading operation of the shield plug 9 described in the second embodiment, the unloading operation of the PCV upper lid 5 described in the third embodiment, and the like. Further, after the replacement with the shield plug 9, it can be used to shield radiation from the inside of the nuclear reactor 2 when carrying out the PCV upper lid 5, the RPV upper lid 10 or the like as needed. The radiation shield 400 according to the present embodiment includes a plurality of shielding bags 401.

  FIG. 10A is a diagram when the shielding bag 401 constituting the radiation shield 400 according to the present embodiment is drained, and FIG. 10B is a diagram when the shielding bag 401 is injected. 10A and 10B, the upper diagram is a front view of the shielding bag 401, and the lower diagram is a bottom view of the shielding bag 401, showing the support member 404 of the shielding bag 401.

  The shielding bag 401 in the present embodiment corresponds to the shielding bag 201 (see FIGS. 6A and 6B) constituting the radiation shielding body 200 according to the embodiment 2 in which the vertical direction and the horizontal direction are interchanged. The shielding bag 401 includes a shape maintaining member 103 on an upper surface, a lower surface, and a side surface parallel to the expansion / contraction direction (lateral direction), and includes a supply / drainage pipe 104, a submersible pump 105, and a winding spring 202. The expansion of the shielding bag 401 in the vertical direction and the direction perpendicular to the expansion / contraction direction is suppressed by the shape maintaining member 103, and the shielding bag 401 is guided by a link mechanism 404A and a traveling wheel 404B, which will be described later, and expands in one lateral direction. The winding spring 202 is provided on one end side in the horizontal direction (stretching direction) of the shielding bag 401 and is fixed to the lower portion of the shielding bag 401. A tension wire 205 that is a linear member is connected to the winding spring 202. The tension wire 205 has one end connected to the winding spring 202 and the other end connected to the other end side in the lateral direction of the shielding bag 401 (the side opposite to the winding spring 20 in the telescopic direction). The winding spring 202 and the tension wire 205 constitute an expandable member that connects one side of the shielding bag 401 and the other side facing the one side, and guides the shielding bag 401 to shrink.

  The shielding bag 401 is installed on the support member 404. The support member 404 includes a link mechanism 404A and traveling wheels 404B at the bottom. The link mechanism 404A is configured by connecting a plurality of plate-shaped members so as to be axially rotatable (for example, configured by connecting a plurality of plate-shaped members in a pantograph shape). As each plate-like member rotates about its axis, the link mechanism 404A can expand and contract in the horizontal direction (one direction in the horizontal direction) as a whole. The link mechanism 404A moves so as to expand or contract as a whole in accordance with the expansion and contraction of the shielding bag 401, and the traveling wheel 404B rotates in accordance with the movement of the link mechanism 404A. The expansion / contraction direction of the shielding bag 401 is the traveling direction of the traveling wheel 404B. In this way, the shielding bag 401 slides in the horizontal direction and expands and contracts. Further, the traveling wheel 404B is connected to a motor (not shown) and serves also as a traveling part of the radiation shield 400. Therefore, the radiation shield 400 according to the present embodiment can be moved on the reactor well 26 by the rotation of the traveling wheel 404B and the movement of the link mechanism 404A, and can be shielded at a target position.

  A procedure for replacing the shield plug 9 with the radiation shield 400 will be described with reference to FIGS. 11A to 11D.

  As shown in FIG. 11A, the radiation shield 400 is installed on the operation floor of the nuclear reactor 2. The radiation shield 400 is in a state of draining and is contracted. The radiation shield 400 is installed at a position corresponding to the right side portion 206A, the left side portion 206B, and the central portion 206C of the shield plug 9 at the time of shielding. Therefore, the three radiation shields 400 are previously arranged on the operation floor of the nuclear reactor 2 at positions that are easy to be installed at these positions during shielding (expansion).

  Next, as shown in FIG. 11B, the right side portion 206A of the shield plug 9 is pulled up to the upper surface of the reactor well 26 by a shield plug pulling jack (not shown), and then the position corresponding to the right side portion 206A of the shield plug 9 is shielded. The solution is injected into the shielding bag 401 of the radiation shielding body 400. Since the shielding bag 401 expands and slides in the lateral direction (the direction toward the center of the reactor well 26 and leftward in FIG. 11B), the radiation shield 400 expands in the lateral direction and performs shielding. Thereby, even if the right side portion 206A of the shield plug 9 is removed, the effect of shielding the radiation from the reactor well 26 can be obtained.

  Next, as shown in FIG. 11C, the left side portion 206B of the shield plug 9 is pulled up to the upper surface of the reactor well 26 by a shield plug pulling jack (not shown), and then the position corresponding to the left side portion 206B of the shield plug 9 is shielded. The solution is injected into the shielding bag 401 of the radiation shielding body 400. Since the shielding bag 401 expands and slides in the lateral direction (the direction toward the center of the reactor well 26 and rightward in FIG. 11C), the radiation shield 400 expands in the lateral direction and performs shielding. Thereby, even if the right side portion 206B of the shield plug 9 is removed, the effect of shielding the radiation from the reactor well 26 can be obtained.

  Next, as shown in FIG. 11D, the central portion 206C of the shield plug 9 is pulled up to the upper surface of the reactor well 26 by a shield plug pulling jack (not shown), and the position corresponding to the central portion 206C of the shield plug 9 is shielded. The solution is injected into the shielding bag 401 of the radiation shielding body 400. Since the shielding bag 401 expands and slides laterally (towards the center of the reactor well 26), the radiation shield 400 expands laterally to perform shielding. Thereby, even if the central portion 206C of the shield plug 9 is removed, the effect of shielding the radiation from the reactor well 26 can be obtained.

  Even if all the shield plugs 9 are removed by the above-described procedure described with reference to FIGS. 11A to 11D, the radiation shield 400 can obtain the effect of shielding the entire open portion of the reactor well 26.

  Next, an example in which the radiation shield 400 according to this embodiment is used for carrying out the PCV upper lid 5 will be described with reference to FIG.

  FIG. 12 is a top view of the reactor well 26 and the DSP 27. A plurality of radiation shields 400 are arranged on the upper surface of the reactor well 26. The radiation shield 400 is arranged to slide toward the center of the reactor well 26 (in the direction of the arrow in FIG. 12) when the shielding bag 401 is expanded. When liquid is injected into the shielding bag 401 of the radiation shield 400, the shielding bag 401 expands and slides in the lateral direction (towards the center of the reactor well 26), so that the radiation shield 400 expands in the lateral direction. To shield. Thereby, the effect of shielding the radiation from the reactor well 26 is obtained.

  In the present embodiment, the material of the shielding bag constituting the radiation shield according to the present invention will be described.

  FIG. 13 is a diagram for explaining the material of the shielding bag constituting the radiation shielding body according to the embodiment of the present invention. The shielding bag is formed of a polyurethane film 1100, an aramid fiber sheet 1110 as a reinforcing material, and a stainless fiber sheet 1120. As shown in FIG. 13, two aramid fiber sheets 1110 are disposed between two polyurethane films 1100, and one stainless fiber sheet 1120 is disposed between two aramid fiber sheets 1110. Arrange to form a shielding bag. The shielding bag formed in this way has an advantage that it is resistant to radiation, can maintain a necessary strength by a reinforcing material, and does not break even if it contacts a structure or the like.

  When there is a low possibility of contact with a structure or the like, without using the stainless fiber sheet 1120, two polyurethane films 1100 and one aramid fiber sheet 1110 disposed therebetween A shielding bag may be formed. The shielding bag having such a configuration has an advantage that the weight can be reduced.

  FIG. 14 is a diagram for explaining another material of the shielding bag constituting the radiation shielding body according to the embodiment of the present invention. The shielding bag is formed of a polyurethane rubber sheet 1130, an aramid fiber sheet 1110 as a reinforcing material, and a stainless fiber sheet 1120. As shown in FIG. 14, two aramid fiber sheets 1110 are arranged between two polyurethane rubber sheets 1130, and one stainless fiber sheet 1120 is interposed between two aramid fiber sheets 1110. To form a shielding bag. The shielding bag formed in this way has the advantage that the extensibility is improved in addition to the advantage of the shielding bag shown in FIG.

  When the possibility of contact with a structure or the like is low, two sheets of polyurethane rubber sheet 1130 and one sheet of aramid fiber 1110 disposed therebetween are used without using the stainless fiber sheet 1120. A shielding bag may be formed from the above. The shielding bag having such a configuration has an advantage that the weight can be reduced.

  In addition, this invention is not limited to said Example, Various modifications are included. For example, the above-described embodiments are described in detail for easy understanding of the present invention, and the present invention is not necessarily limited to an aspect including all the configurations described. In addition, a part of the configuration of a certain embodiment can be replaced with the configuration of another embodiment. It is also possible to add the configuration of another embodiment to the configuration of one embodiment. Further, with respect to a part of the configuration of each embodiment, the configuration of another embodiment can be added, deleted, or replaced.

  DESCRIPTION OF SYMBOLS 1 ... Boiling water type nuclear power plant, 2 ... Reactor, 3 ... Reactor containment vessel (PCV), 4 ... Reactor building, 5 ... PCV upper cover, 6 ... Dry well, 7 ... Pressure suppression room, 8 ... Vent passageway, DESCRIPTION OF SYMBOLS 9 ... Shield plug, 10 ... RPV top cover, 11 ... Reactor pressure vessel (RPV), 12 ... Core, 13 ... Steam separator, 14 ... Steam dryer, 15 ... Core shroud, 16 ... Fuel assembly, 17 ... Core support plate, 18 ... upper lattice plate, 19 ... control rod guide tube, 20 ... control rod, 21 ... control rod drive mechanism housing, 22 ... lower mirror, 23 ... concrete mat, 24 ... pedestal, 25 ... gamma ray shield , 26 ... Reactor well, 27 ... Dryer separator storage pool (DSP), 28 ... Spent fuel storage pool (SFP), 100 ... Radiation shield, 101 ... Shielding bag, 102 ... Bar-shaped member, 103 ... Shape maintenance part , 104 ... Feed / drain pipe, 105 ... Submersible pump, 106 ... Upper lid, 107 ... Support member, 108 ... Gap, 109 ... Lifting balance, 110 ... Feed / drain hole, 111 ... Manifold, 112 ... Drain pump, 113 ... Supply / drain pipe, 151 ... shielding bag, 200 ... radiation shielding body, 200A ... first shielding body, 200B ... second shielding body, 200C ... third shielding body, 201 ... shielding bag, 202 ... winding spring, 203 ... hanging 204, seating ring, 205 ... tension wire, 206A ... right side of shield plug, 206B ... left side of shield plug, 206C ... central part of shield plug, 207 ... support member, 300 ... radiation shield, 301 ... slide Mechanism 302 ... Link arm 303 ... Extrusion cylinder 304 ... Supporting member 400 ... Radiation shield 401 ... Shielding bag 404 ... Support member, 404A ... link mechanism, 404B ... running wheel, 1100 ... polyurethane film, 1110 ... aramid fiber sheet, 1120 ... stainless fiber sheet, 1130 ... polyurethane rubber sheet.

Claims (11)

A plurality of radiation shielding bags connected to each other and fixed to the support member;
Each of the plurality of radiation shielding bags includes therein a member that can be expanded and contracted by connecting one side in the vertical direction or the lateral direction of the radiation shielding bag and the other side facing the one side,
Each of the plurality of radiation shielding bags expands when a liquid having a radiation shielding effect is injected, and shrinks while being guided by the extendable member when the liquid is discharged.
A radiation shield characterized by that. The extendable member is a rod-like member that connects the upper and lower portions of the radiation shielding bag,
Each of the plurality of radiation shielding bags further includes an expandable / contractible supply / drainage pipe and a submersible pump inside, and is placed on the support member,
Each of the plurality of radiation shielding bags expands upward when the liquid is injected from the supply / drainage pipe, and when the liquid is discharged from the supply / drainage pipe by the submersible pump, The radiation shield according to claim 1, wherein the radiation shield is reduced in a downward direction while being guided by the member. A manifold installed under the radiation shielding bag, and a drainage pump connected to the manifold,
The extendable member is a rod-like member that connects the upper and lower portions of the radiation shielding bag,
Each of the plurality of radiation shielding bags further includes a supply / drainage hole on the lower surface, and is placed on the support member,
The manifold is connected to each of the supply and drainage holes of the radiation shielding bag,
Each of the plurality of radiation shielding bags expands upward when the liquid is injected from the manifold, and is guided to the rod-shaped member when the liquid is discharged from the manifold by the drain pump. The radiation shield according to claim 1, which shrinks downward. The extendable member is a winding spring provided on the upper part of the radiation shielding bag, and a linear member having one end connected to the winding spring and the other end connected to the lower part of the radiation shielding bag,
Each of the plurality of radiation shielding bags further includes an expandable / contractible supply / drainage pipe and a submersible pump inside, and is suspended from the support member,
Each of the plurality of radiation shielding bags expands downward when the liquid is injected from the supply and drainage pipe, and when the liquid is discharged from the supply and drainage pipe by the submersible pump, the hoisting is performed. The radiation shield according to claim 1, wherein the radiation shield is guided by the linear member by an action of a spring and contracts upward. A link member provided on the plurality of radiation shielding bags;
The radiation shield according to claim 4, wherein the link member includes a plurality of plate-like members connected to each other so as to be axially rotatable, is extensible as a whole, and extends in accordance with the expansion of the radiation shielding bag. . The extendable member includes a winding spring provided on one end side in the lateral direction of the radiation shielding bag, one end connected to the winding spring, and the other end connected to the other end side in the lateral direction of the radiation shielding bag. A linear member,
Each of the plurality of radiation shielding bags further includes an expandable / contractible supply / drainage pipe and a submersible pump inside, and is placed on the support member,
The support member includes a link mechanism that can expand and contract in the lateral direction at the bottom,
The link mechanism is configured such that a plurality of plate-like members are connected to each other so as to be axially rotatable, and can expand and contract in the lateral direction as a whole,
Each of the plurality of radiation shielding bags expands in the lateral direction when the liquid is injected from the supply / drain pipe, and when the liquid is discharged from the supply / drain pipe by the submersible pump, The radiation shield according to claim 1, wherein the radiation shield is guided by the linear member by the action of a winding spring and contracts in the lateral direction.   6. The radiation shield according to claim 2, wherein each of the plurality of radiation shielding bags includes a member formed of a metal wire or plate, or fiber reinforced plastic on an outer surface.   The radiation shielding body according to claim 6, wherein each of the plurality of radiation shielding bags includes a member made of a metal wire or plate or fiber reinforced plastic on an upper surface, a lower surface, and a side surface parallel to the lateral direction. .   The radiation shielding body according to any one of claims 1 to 6, wherein the radiation shielding bag includes a polyurethane film and an aramid fiber sheet disposed between the polyurethane films.   The radiation shielding body according to claim 1, wherein the radiation shielding bag includes a polyurethane rubber sheet and an aramid fiber sheet disposed between the polyurethane rubber sheets.   The radiation shielding body according to claim 9 or 10, wherein the radiation shielding bag further includes a stainless fiber sheet disposed between the aramid fiber sheets.

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