JP6933837B2 - Vent structure of container - Google Patents

Description

The present invention relates to a vent structure of a container for containing radioactive substance-containing waste.

Due to the accident at the Fukushima Daiichi Nuclear Power Station caused by the Great East Japan Earthquake, the contaminated water accumulated inside the reactor building is being treated by multiple purification facilities, including a multi-nuclide removal facility. To date, all purification treatments for highly contaminated water containing strontium, excluding the water remaining at the bottom of the storage tank, have been completed.
The used adsorbents and sedimentation products generated from the multi-nuclide removal equipment during the treatment of contaminated water are stored in a high-performance polyethylene container (hereinafter referred to as HIC). .. In the future, it will be necessary to treat and dispose of radioactive material-containing waste generated during the decommissioning work in parallel with the treatment of some contaminated water.
The form and storage procedure of these radioactive material-containing wastes have not yet been decided, but they have different specifications from the polyethylene HIC and can be stably stored and stored in various environments. If there is a container (hereinafter referred to as a storage container), the range of processing and disposal methods will be expanded.

Conventionally, a concrete storage container has been used to store radioactive substance-containing waste. For example, Patent Document 1 describes a storage container having an inner can for storing radioactive substance-containing waste and a metal outer can in which the inner can is loaded and sealed. This inner can contains cement and a group of powdery or spherical small steel balls having an average particle size of 100 to 250 μm added in the range of 1 to 4 and a weight ratio of 1 to 4 to cement. It is composed of a group of powdered or spherical large steel balls having an average particle size of 600 to 850 μm and a radiation shielding concrete having ^{a density of 4.0 g / cm 3 or more after hardening.} This storage container has a two-layer structure of an inner can and an outer can, the density of the inner can is high, and small steel balls and large steel balls are uniformly distributed, so that high radiation shielding ability can be uniformly exhibited. can.

Japanese Unexamined Patent Publication No. 2009-276194

Radioactive material-containing waste contained in a storage container may generate gas (for example, hydrogen gas). If the amount of this hydrogen generated is large, the storage container may be damaged by the hydrogen pressure. If the storage container is damaged, there is a problem that radioactive substance-containing waste leaks to the outside. Therefore, the storage container needs a gas discharge port (vent structure) for discharging the gas generated inside to the outside.

When the storage container is provided with a gas discharge port, when the storage container is exposed to rain, rainwater enters the inside of the storage container through the discharge port. Then, if rainwater collects inside the storage container and the amount of rainwater exceeds the permissible amount, there is a possibility that rainwater in contact with radioactive substance-containing waste is discharged from the storage container to the outside.
Therefore, there is a demand for a vent structure in which rainwater (liquid) does not enter the storage container for radioactive substance-containing waste from the outside and the gas inside is discharged to the outside.

Therefore, an object of the present invention is to provide a vent structure in which the gas inside the container is discharged to the outside of the container and the liquid does not enter the inside of the container from the outside.

The vent structure of the present invention includes a communication hole that communicates the inside and the outside of the container in which the radioactive substance-containing waste is stored, and a vent member provided in the communication hole, and the liquid on the outside of the container passes through the vent member. It is characterized in that the gas inside the container does not penetrate inside and the gas inside the container is discharged to the outside of the container via the vent member.

The vent structure of the present invention is characterized in that the vent member is a pipe, and the tip of the pipe is formed so as to face downward in the height direction of the container.

The vent structure of the present invention is characterized in that the vent member is a pipe and a covering member is provided at an opening of the pipe.

The vent structure of the present invention is characterized in that the vent member is made of a gas permeable material in which a liquid cannot move and a gas can move.

In the vent structure of the present invention, the container is an inner container in which radioactive substance-containing waste is stored, an outer container in which the inner container is arranged inside, and a filler filled between the inner container and the outer container. The communication hole is an inner communication hole formed in the inner container and an outer communication hole formed in the outer container.

In the vent structure of the present invention, the liquid on the outside of the container does not enter the inside through the vent member, and the gas inside the container is discharged to the outside of the container through the vent member in the communication hole. Therefore, even when the container is exposed to rain, it is possible to prevent rainwater from accumulating inside the container and flowing out radioactive substance-containing waste to the outside, and in addition, a gas (for example, hydrogen) generated from the radioactive substance-containing waste. It is possible to prevent the container from being damaged by the pressure of.

The vent structure of the present invention includes an inner container in which radioactive substance-containing waste is contained and a communication hole is formed, an outer container in which the inner container is arranged inside and an outer communication hole is formed, and an inner container. It can also be applied to a container provided with a filler to be filled between the outer container.

It is a figure which shows the radioactive substance-containing waste storage container provided with the vent structure which concerns on 1st Embodiment of this invention. (A) sectional view, (b) bottom view It is a figure which shows the outer container which constitutes the radioactive substance-containing waste storage container provided with the vent structure which concerns on 1st Embodiment of this invention. (A) Cross-sectional view, (b) Plan view of outer lid portion, (c) Plan view of outer side wall portion It is a figure which shows the inner container of the radioactive substance-containing waste storage container provided with the vent structure which concerns on 1st Embodiment of this invention. (A) Cross-sectional view, (b) Plan view of inner lid, (c) Plan view of small lid, (d) Plan view of inner side wall It is sectional drawing which shows the state which the reinforcing bar is contained in the inner container provided with the vent structure which concerns on 1st Embodiment of this invention. It is a figure which shows the state which the filler is provided in the radioactive substance-containing waste storage container provided with the vent structure which concerns on 1st Embodiment of this invention. (A) sectional view, (b) top view It is a figure for demonstrating the vent structure which concerns on 1st Embodiment of this invention. It is a figure which shows the vent structure which concerns on the 2nd Embodiment of this invention. It is a figure which shows the vent structure which concerns on the 3rd Embodiment of this invention.

The vent structure of the present invention can be provided in a single-layered container or a multi-layered container. In the first to third embodiments, the vent structure provided in the container having the three-layer structure will be described with reference to FIGS. 1 to 8.

[First Embodiment]
As shown in FIG. 1A, the radioactive material-containing waste storage container 1 (hereinafter referred to as the storage container 1) provided with the vent structure 100 according to the present embodiment has a three-layer structure. The storage container 1 is a filler filled between the inner container 30 in which radioactive substance-containing waste is stored, the outer container 10 in which the inner container 30 is arranged, and the inner container 30 and the outer container 10. It has 50 and. The strength of the filler 50 is designed to be smaller than that of the inner container 30 and the outer container 10.
Hereinafter, the configurations of the outer container 10, the inner container 30, the filler 50, and the vent structure 100 will be described in order. In addition, in FIGS. 1 to 5, the description of the vent structure 100 is omitted, and the details will be described with reference to FIGS. 6 to 8.

[Outer container 10]
As shown in FIG. 2A, the outer container 10 has an outer lid portion 11, an outer side wall portion 12, and an outer bottom portion 13. The outer container 10 is a metal cylindrical container, and for the outer container 10, for example, a stainless steel plate can be used.
As shown in FIG. 2B, the outer lid portion 11 has a circular shape, and a lid-side flange portion 16 is formed at the lower end of the outer lid portion 11. The lid-side flange portion 16 is formed with a plurality of through holes 15 penetrating the upper and lower portions at equal intervals (12 in the present embodiment).
As shown in FIG. 2C, a side wall side flange portion 18 is formed at the upper end of the outer side wall portion 12. The side wall side flange portion 18 overlaps with the lid side flange portion 16 of the outer lid portion 11. A plurality of through holes 19 penetrating the upper and lower sides are formed in the side wall side flange portion 18. The through holes 19 are formed at positions corresponding to the through holes 15 of the outer lid portion 11.

Two sets of connecting portions 17 facing each other are formed on the upper outer circumference of the outer side wall portion 12 (FIG. 2 (c)). These connecting portions 17 are provided at equal intervals. The connecting portion 17 has a plate shape having a flat surface portion 17A, and one through hole 17B penetrating the flat surface portion 17A is formed (FIG. 2A). Further, the connecting portion 17 has a substantially trapezoidal shape, and the lower side portion thereof is connected to the outer container 10. The shape of the connecting portion 17 is not limited to a trapezoidal shape, and may be a rectangular shape or a triangular shape.
Further, the connecting portion 17 also plays a role of a hanging portion, a wire is connected to the through hole 17B formed in the connecting portion 17, and the storage container 1 is transported by a crane.

The outer bottom portion 13 is a disk having a diameter larger than the diameter of the outer side wall portion 12, and its outer edge is wound around the lower end of the outer side wall portion 12 and is coupled to the outer side wall portion 12. An annular cushioning member 20 is attached and fixed to the lower surface of the outer bottom portion 13 separately from the outer container 10 (FIG. 1 (b)). The cushioning member 20 has an annular shape and is attached along the circumference of the lower surface of the outer bottom portion 13. The cushioning member 20 is made of metal, and for the cushioning member 20, for example, a stainless steel plate can be used. The cushioning member 20 is fixed to the outer bottom portion 13 by welding. The length of the cushioning member 20 in the height direction is designed to be 2 cm to 20 cm.
The strength of the outer container 10 is higher than that of the inner container 30, and the yield strength of the outer container 10 is preferably 205 MPa or more and 400 MPa or less.
Further, in order to prevent the storage container 1 from tipping over, the aspect ratio, which is the ratio of the height of the outer container 10 to the diameter of the outer container 10, is preferably 1.2 to 0.3.

[Inner container 30]
The inner container 30 is arranged inside the outer container 10 and contains radioactive-containing waste. As shown in FIG. 3A, the inner container 30 has an inner lid portion 31, an inner side wall portion 32, and an inner bottom portion 33, and an inner bottom portion 33 is provided between the inner side wall portion 32 and the inner bottom portion 33. The haunch portion 35 is formed so that the inner diameter and the outer diameter of the inner container 30 become smaller. That is, the inside of the inner side wall portion 32 is inclined from the upper side to the lower side and is formed in a tapered shape.
The haunch portion 35 is inclined on both the inner and outer sides of the inner container 30.
Further, the outer diameter of the inner container 30 is smaller than the inner diameter of the outer container 10, and the height of the inner container 30 is designed to be lower than the height of the outer container 10.
The inner container 30 is a cylindrical container, and the inner container 30 includes polymer impregnated concrete (hereinafter referred to as PIC) or steel fiber reinforced polymer impregnated concrete (hereinafter referred to as PIC). , SFPIC.) Is used.
The thickness of the inner container 30 is designed to be 100 mm or less.

As shown in FIG. 3B, the inner lid portion 31 has a circular shape, and the inner container 30 is sealed by being fitted to the inner side wall portion 32. A plurality of through holes 36 penetrating the upper and lower parts are formed on the circumference of the upper surface of the inner lid portion 31 (12 in this embodiment). Further, in the center of the inner lid portion 31, a window portion 37 that vertically penetrates the lid portion 31 is formed. A plurality of holes 42 are formed around the window portion 37. A small lid 38 is attached to the window portion 37.
As shown in FIG. 3C, the small lid 38 is formed with a plurality of through holes 43 penetrating the upper and lower parts, and is attached to the window portion 37 by bolts or the like through the through holes 43.
As shown in FIG. 3D, a plurality of holes 34 are formed on the upper end surface of the inner side wall portion 32. The hole 34 is formed at a position corresponding to the through hole 36.
Further, as the inner container 30, as shown in FIG. 4, a container containing the reinforcing bar 39 can also be used. The reinforcing bar 39 is spirally provided inside the inner side wall portion 32, and is provided in a mesh shape inside the inner bottom portion 33.
The compressive strength of the inner container 30 is preferably 120 MPa or more and 250 MPa or less.

[Filler 50]
As shown in FIG. 5A, the filler 50 fills the gap formed between the outer container 10 and the inner container 30. As the filler 50, one in which the strength of the layer of the filler 50 is smaller than that of the outer container 10 and the inner container 30 is used. For the filler 50, for example, mortar can be used.
The mortar filler 50 is filled in the gap between the outer container 10 and the inner container 30 and then cured to form a layer. As shown in FIG. 5B, the filler 50 is provided in the gap between the outer container 10 and the inner container 30, and is arranged in an annular shape between the outer container 10 and the inner container 30. The compressive strength of the filler 50 is preferably 15 MPa or more and 60 MPa or less.
The width of the gap between the outer container 10 and the inner container 30 is preferably 2 cm to 15 cm, and the width of the gap is appropriately changed depending on the type of the filler 50 used.
In addition to mortar, a corrugated metal plate, a bubble paste, a foamed resin body, and a rubber elastic material can be used as the filler 50.

[Vent structure 100]
The vent structure 100 (106) is formed on the inner lid portion 31 and the outer lid portion 11 as shown in FIG. 6 (a). Specifically, as shown in FIG. 6B, the vent structure 100 is formed in the inner lid portion 31 and has an inner communication hole 101 that communicates the inside and the outside of the inner container 30 and an inner communication hole 101. It includes a liquid-resistant gas permeation member 102 provided inside, and an outer communication hole 103 formed in the outer lid portion 11 that communicates the inside and the outside of the outer container 10. The upper part of the storage container 1 has a triple structure in which a filler 50 is not filled between the outer container 10 and the inner container 30, that is, a space is formed between the outer lid portion 11 and the inner lid portion 31. Is doing.
The outer communication hole 103 is provided at a position deviated from the inner communication hole 101 in the radial direction.
The liquid-resistant gas permeation member 102 cannot allow the liquid to enter from the outside of the inner container 30, and the gas is discharged to the outside from the inside of the inner container 30. For the liquid-resistant gas permeation member 102, for example, a hydrophobic porous membrane made of ceramic, silicon rubber, or polyethylene terephthalate can be used. In the present embodiment, the liquid-resistant gas permeation member means a member made of a material in which the liquid cannot move and the gas can move.

A pipe member 104 is provided in the outer communication hole 103. One end of the pipe member 104 protrudes to the outside of the outer lid portion 11, and the other end is fitted into the outer communication hole 103. Further, the pipe member 104 is provided with a cap member 105 as a covering member from above. The cap member 105 is fixed to the upper surface of the outer lid portion 11, and the opening of the pipe member 104 is covered by the cap member 105.
For the cap member 105, for example, full-shaped steel (manufactured by SUS) can be used. The cap member 105 is composed of a flat ceiling wall 105A and a pair of side walls 105B connected to the ceiling wall 105A, and an opening 105C is formed between the side walls 105B. The cap member 105 is installed on the upper surface of the outer lid portion 11 so that the ceiling wall 105A faces the top-bottom direction (upper side) of the pipe member 104.
In addition to the above, the cap member 105 may have a structure in which a through hole is formed in the side wall of the box-shaped member, for example.

Further, as another example, the vent structure 106 shown in FIG. 6 (c) can be used. In this vent structure 106, a liquid-resistant gas permeation member 102 is provided inside the inner communication hole 101, and a pipe 107 having a flange portion is provided on the upper surface of the outer lid portion 11. A lid 108, which is a cylindrical member having a flange portion, is attached to the pipe 107.
A sheet-shaped liquid-resistant gas permeation member 102 is provided between the pipe 107 and the lid 108 so as to cover the opening, and the pipe 107 and the lid 108 are fixed by fastening the flange portions to each other with bolts. Will be done.

Next, the action and effect of the vent structure 100 (106) according to the first embodiment will be described.
In the vent structure 100 according to the present embodiment, the cap member 105 is provided from the upper side of the pipe member 104, and the opening of the protruding pipe member 104 is covered by the cap member 105. Therefore, even when the storage container 1 stored outdoors is exposed to rain, it is possible to prevent rainwater (liquid) from entering from the outside to the inside of the outer container 10 through the pipe member 104. Further, since the liquid-resistant gas permeation member 102 provided in the inner communication hole 101 is a material that does not allow liquid to enter from the outside of the inner container 30, even if rainwater invades from the outside of the outer container 10. Rainwater does not enter the inside of the inner container 30 through the inner communication hole 101.
As described above, in the storage container 1 of the present embodiment, rainwater is discharged from the outside of the storage container 1 to the inside of the inner container 30 in which the radioactive substance-containing waste is stored by the cap member 105 and the liquid-resistant gas permeation member 102. It can be surely prevented from invading.

Further, since the vent structure 100 according to the present embodiment is provided with the liquid-resistant gas permeation member 102 through which the gas can permeate in the inner communication hole 101, the gas (for example, hydrogen) generated inside the inner container 30 is resistant. It passes through the liquid / gas permeation member 102 and is discharged to the outside of the inner container 30 (arrow).
This gas is discharged to the outside of the outer container 10 via the pipe member 104, and is discharged to the outside of the storage container 1 through the opening 105C.

Further, in the vent structure 106 according to the present embodiment, the opening of the pipe 107 provided above the opening of the outer communication hole 103 is closed by the lid 108. A liquid-resistant gas permeation member 102 is provided between the pipe 107 and the lid 108. Then, even when the storage container 1 is exposed to rain, the liquid-resistant gas permeation member 102 prevents rainwater from entering, so that it is possible to prevent rainwater from entering the inside of the outer container 10 through the pipe 107. ..

From the above, by providing the vent structures 100 and 106 according to the present embodiment in the storage container 1, rainwater collects inside the inner container 30 even when the storage container 1 is exposed to rain, and waste containing radioactive substances on the outside. In addition to being able to prevent objects from flowing out, it is possible to prevent the inner container 30 (container container 1) from being damaged by the pressure of the gas generated from the radioactive substance-containing waste.

[Second Embodiment]
Next, the vent structure 120 according to the second embodiment will be described with reference to FIG. 7.
The vent structure 120 according to the first embodiment is provided with a pipe 121 in the inner communication hole 101 instead of the liquid resistant gas permeation member 102 described in the first embodiment. Unlike (106), other structures are the same as the vent structure 100 (106) of the first embodiment. Therefore, the explanation will be focused on the different parts, and the description of the similar parts will be omitted as appropriate.

As shown in FIG. 7A, the vent structure 120 is provided with a pipe 121 in the inner communication hole 101. The pipe 121 is provided in the outer communication hole 103 so that one end protrudes to the outside of the inner lid portion 31. At this time, the tip of the pipe 121 is arranged in the gap between the outer lid portion 11 and the inner lid portion 31. The pipe 121 is in close contact with the inner communication hole 101 by the epoxy resin adhesive 109.
As another example, the vent structure 122 shown in FIG. 7 (b) can be used. The vent structure 122 has a structure in which, in the vent structure 106 according to the first embodiment, a pipe 121 is provided in place of the liquid-resistant gas permeation member 102 in the inner communication hole 101 that communicates the inside and the outside of the inner container 30. Have. The pipe 121 is also provided in the outer communication hole 103 so that one end protrudes to the outside of the inner lid portion 31. At this time, the tip of the pipe 121 is arranged in the gap between the outer lid portion 11 and the inner lid portion 31. The pipe 121 is in close contact with the inner communication hole 101 by the epoxy resin adhesive 109.

Next, the action and effect of the vent structure 120 (122) according to the present embodiment will be described.
In the vent structure 120 (122) according to the present embodiment, the tip of the pipe 121 provided in the inner communication hole 101 is provided so as to protrude from the inner lid portion 31. Therefore, if rainwater (liquid) invades along the upper surface of the inner lid portion 31, the tip portion of the pipe 121 becomes an obstacle and the rainwater does not reach the opening of the pipe 121.
Therefore, the vent structure 120 (122) of the present embodiment can prevent rainwater from entering the inside of the inner container 30 from the outside of the inner container 30.

[Third Embodiment]
Next, the vent structure 130 according to the third embodiment will be described with reference to FIG.
The vent structure 130 according to the present embodiment is different from that of the first embodiment and the second embodiment in that a pipe member 131 penetrating the inner communication hole 101 and the outer communication hole 103 is provided. Hereinafter, the characteristic portion of the vent structure 130 according to the present embodiment will be mainly described.

The inner communication hole 101 and the outer communication hole 103 constituting the vent structure 130 of the present embodiment have substantially the same diameter and are provided at the same position in the radial direction.
The pipe member 131 is composed of a semicircular curved portion 132 and a straight portion 133 connected to the curved portion 132.
The pipe member 131 is provided so that the straight portion 133 is in contact with the inner walls of the inner connecting hole 101 and the outer connecting hole 103, and the curved portion 132 is arranged outside the outer container 10. The opening 134 of the curved portion 132 is formed so as to face downward in the height direction.

The opening 135 of the straight portion 133 and the inside of the inner container 30 are in communication with each other. Therefore, the inside of the inner container 30 and the outside of the outer container 10 are communicated with each other via the pipe member 131.
Further, the straight portion 133 and the inner wall of the inner lid portion 31 are in close contact with each other with the epoxy resin adhesive 109.

In the vent structure 130 according to the present embodiment, the opening 134 of the curved portion 132 arranged on the outside of the outer container 10 is provided downward in the height direction. Therefore, even if the storage container 1 is exposed to rain, rainwater does not enter through the opening 134.
Further, in the vent structure 130 of the present embodiment, since the pipe member 131 communicates between the inside of the inner container 30 and the outside of the outer container 10, the gas generated inside the inner container 30 is passed through the pipe member 131. It can be discharged to the outside of the storage container 1.

Although the present embodiment has been described above, other than this, the configuration described in the above embodiment can be selected or changed as appropriate without departing from the gist of the present invention. ..
For example, in the vent structure 120 (122) of the second embodiment, the liquid-resistant gas permeation member 102 can be provided inside the pipe 121, and in the vent structure 130 of the third embodiment, the liquid-resistant gas permeation member 102 can be provided inside the pipe member 131. By doing so, even if rainwater invades the inside of the pipe 121 or the pipe member 131, it is possible to reliably prevent the rainwater from invading the inside of the inner container 30.
Further, the shape of the curved portion 132 of the pipe member 131 constituting the vent structure 130 of the third embodiment is not limited to a semicircular shape, and the opening 134 may be formed downward in the height direction. Just do it. Further, the pipe member 131 may not be provided so as to communicate with the inner communication hole 101. In this case, the curved portion 132 is provided in the outer communication hole 103, and the liquid-resistant gas permeation member 102 can be provided in the inner communication hole 101.

1 Radioactive material-containing waste storage container (containment container)
10 Outer container 11 Outer lid 12 Outer side wall 13 Outer bottom 15 Through hole 16 Lid side flange 17 Connecting part 17A Flat part 17B Through hole 18 Side wall side flange 19 Through hole 20 Cushioning member 30 Inner container 31 Inner lid 32 Inner side wall 33 Inner bottom 34 Hole 35 Haunch 36 Through hole 37 Window 38 Small window 39 Reinforcing bar 40 Dam ring 41 Reinforcing material 42 Hole 43 Through hole 44 Bolt 45 Epoxy resin adhesive 50 Filling material 100, 106, 110, 120 , 122, 130 Vent structure 101 Inner communication hole 102 Liquid resistant gas permeation member 103 Outer communication hole 104 Pipe member 105 Cap member 105A Ceiling wall 105B Side wall 105C Opening 107 Pipe 108 Lid 109 Epoxy resin adhesive 121 Pipe 131 Pipe member 132 Curved Part 133 Straight part 134 Opening 135 Opening

Claims (7)

A communication hole that communicates the inside and outside of a container having an inner container for containing radioactive substance-containing waste and an outer container in which the inner container is arranged.
A vent member provided in the communication hole is provided.
The communication hole is composed of an inner communication hole formed in the inner container and an outer communication hole formed in the outer container, and the inner communication hole and the outer communication hole are formed in the inner container and the outer side. It opens in the space formed between the container and
The liquid on the outside of the container does not enter the inside through the vent member, and the gas inside the container is discharged to the outside of the container through the vent member.
Vent structure characterized by that. The inner communication hole and the outer communication hole are formed at positions shifted in the radial direction.
The vent structure according to claim 1. The vent member provided in the inner communication hole is a pipe, and the tip of the pipe protrudes to the outside of the inner container and is arranged in the space.
The vent structure according to claim 1 or 2 , wherein the vent structure is characterized in that. The vent member provided in the outer communication hole is a pipe, and the tip of the pipe is formed so as to face downward in the height direction of the container.
The vent structure according to any one of claims 1 to 3, wherein the vent structure is characterized in that. The vent member provided in the outer communication hole is a pipe, and a covering member is provided in the opening of the pipe.
The vent structure according to any one of claims 1 to 3 , wherein the vent structure is characterized in that. The vent member has a hydrophobic porous membrane in which a liquid cannot move and a gas can move.
The vent structure according to any one of claims 1 to 5, wherein the vent structure is characterized in that. A filler provided between the inner container and the outer container.
The vent structure according to any one of claims 1 to 6, wherein the vent structure is characterized in that.

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