JP2003130987A - Air-tight vessel for radioactive material and its assembling method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the deformation of an air-tight vessel body for radioactive materials during welding a primary lid to the vessel body, and obtain a good contact of the vessel body and the lid by welding, by reducing the thickness of weld beat for contacting compared with the conventional ones. SOLUTION: The vessel comprises a vessel body 12 having an open upper end and made of metal wherein radioactive material is contained, a support member 13 attached to the inner surface of peripheral wall of the vessel body, a shield lid 14 arranged inside the vessel body and supported by the support member for putting on, a primary lid 15 positioning the upside of the shield lid, arranged inside the vessel body and contacted to the vessel body by welding, a secondary lid 16 positioning the upside of the primary lid, arranged parallel to the vessel body and contacted to the vessel body by welding, and a screw rod 21 (fixing means) for fixing the primary lid to the vessel body.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a closed container for radioactive material and a method for assembling the same.

[0002]

2. Description of the Related Art Spent nuclear fuel (radioactive material) generated at a nuclear power plant is stored in a closed container, transported to an intermediate treatment facility and stored for a predetermined period, and then transported to a retreatment facility for reprocessing. As a result, it is used again as fuel. The closed container for storing the spent nuclear fuel is classified into an external container made of concrete (concrete cask) and an integrated container (metal cask).

The former type of closed container is a container body made of metal having an open upper end and containing a radioactive substance, a supporting member attached to the inner peripheral surface of the peripheral wall of the container body, and the inside of the container body. A shield lid that is horizontally disposed on the support member and supported by the support member, and a primary lid that is located above the shield lid and that is disposed inside the container body and is welded to the container body and joined thereto. And a secondary lid which is located above the primary lid and is horizontally arranged in the container body and welded to and joined to the container body.

[0004]

In the conventional closed container for containing the spent nuclear fuel, there is a problem in joining the container body and the lid for closing the container body.

That is, in order to join the primary lid with the container body, the TIG has a predetermined joining strength and sealability.
Larger weld bead thickness (eg 1
6 mm) is used for welding, and as a result, a large amount of heat is input to the container body during welding. For this reason, a large thermal deformation occurs in the container body made of metal after welding to the primary lid, and when the secondary lid is subsequently placed inside the container body to join the container body, the thermally deformed container The cross-sectional shape of the main body does not match the outer shape of the secondary lid. Therefore, in order to satisfactorily bond the secondary lid to the container body, it is necessary to cut and correct the inner peripheral surface of the container body or the outer peripheral surface of the secondary lid by machining, which requires a great deal of labor and cost. Will be. Since this machining must be carried out locally such as at a nuclear power plant that stores the spent fuel in a closed container, there are significant problems in terms of cost and processing accuracy.

In the process of inserting the spent nuclear fuel into the container body in the assembly of this closed container, the container body is placed upright inside the pool in which water is stored, and the nuclear fuel is hung from above and the upper end of the container body is suspended. Insert it from the open part,
Then, the shielding lid is hung from above and inserted into the inside of the container main body from the upper end open portion for fitting, and then the container main body is taken out from the pool. In this process, since the work of inserting the shield lid into the container body is performed underwater, it is very difficult to insert the shield lid into the container body so that the shield lid is aligned with the upper end opening portion and does not collide with the peripheral wall portion. Therefore, the gap between the outer peripheral surface of the shielding lid and the inner surface of the peripheral wall portion of the container body is set to be sufficiently large (5 to 10 mm) to allow a margin, and when the shielding lid is inserted into the container body, I try to avoid a collision.

By the way, if the outer container containing the container body falls due to a virtual accident such as an earthquake, the peripheral wall of the container body made of metal is deformed (elliptical) and collides with the outer peripheral surface of the shielding lid. However, the cross-sectional deformation amount corresponds to the size of the gap between the peripheral wall portion of the container body and the outer peripheral surface of the shielding lid. Therefore, if the size of the gap between the peripheral wall portion of the container body and the outer peripheral surface of the shielding lid is large, the amount of sectional deformation of the container body is large, and if the amount of sectional deformation of the container body is large, the container body is above the shielding lid. The joints formed by welding the primary lid and the secondary lid arranged inside may be deformed, and the stress at the joints between these lids and the container body may increase and the degree of sealing may decrease.

Therefore, in these circumstances, in the conventional closed container, it is demanded to obtain a good joint between the container body and the lid by welding.

According to the present invention, the weld bead thickness for welding and joining the primary lid to the container body is made smaller than that of the conventional one, and deformation of the container body is prevented when welding and joining the primary lid to the container body. However, it is an object of the present invention to provide a closed container for radioactive material, which can obtain a welded joint between the container body and the lid in a good form.

According to the present invention, the size of the gap between the shielding lid and the container body is made smaller than that of the conventional one (0 to 1 m), and the deformation of the container body when the outer container is virtually tumbled is suppressed to be small. It is an object of the present invention to provide a method for assembling a closed container for radioactive substances, which enables a welded joint between a main body and a lid to be obtained.

[0011]

According to a first aspect of the present invention, there is provided a closed container for radioactive material, comprising: a container body made of metal having an open upper end and containing a radioactive substance; and an inner peripheral surface of a peripheral wall portion of the container body. A supporting member attached to the container body; a shielding lid disposed inside the container body and mounted and supported on the supporting member; and a shielding lid located above the shielding lid and disposed inside the container body to the container body. A primary lid welded and joined, and a secondary lid positioned above the primary lid and disposed in the container body and welded and joined to the container body,
And a lid fixing means for fixing the primary lid to the container body.

According to a second aspect of the present invention, in the closed container for radioactive material according to the first aspect, the lid fixing means is inserted from the peripheral portion of the primary lid through the peripheral portion of the shielding lid in the vertical direction. In addition, the lower end is fixed to the support member, and the upper end is a bar member that presses the primary lid.

According to a third aspect of the present invention, in the closed container for radioactive material according to the first aspect, the lid fixing means is formed on a screw portion formed on an inner surface of the container body and on an outer peripheral surface of the primary lid. And a threaded portion that is screwed into the threaded portion.

In the method for assembling the closed container for radioactive material according to the fourth aspect of the present invention, the container main body is made of metal with the upper end opened and the radioactive material is stored inside, and the container main body is attached to the inner peripheral surface of the peripheral wall portion. A support member, a shield lid that is disposed inside the container body and is placed and supported by the support member, and welding is performed on the container body that is located above the shield lid and that is disposed inside the container body. In a closed container including a lid joined together, when the shielding lid is inserted into the inside of the container body from the upper end opening portion, the shielding lid is detachably attached to the supporting member and is upwardly moved from the upper end opening portion of the container body. A plurality of projecting guide rods are provided upright inside the container body, and the shield lid is lowered while guiding the guide rods through a plurality of holes formed through the shield lid in the up-down direction. Book Characterized by inserting from the upper opening to the interior of the container body.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a cross-sectional view showing an airtight container and an outer container, FIG. 2 is a plan view showing an arrangement of support members in the airtight container, and FIG. 3 is an enlarged cross-sectional view showing a lid joint portion of the airtight container.

In FIG. 1, reference numeral 1 denotes an external container, which is fitted into a container main body 2 made of concrete in the form of a vertical cylinder having an upper end formed therein, and an upper end opening of the container main body 2. Disc-shaped concrete lid 3
And a closed container 11 is stored inside. An air inlet 4 is formed at the lower end of the container body 2 and an air outlet 5 is formed at the upper end of the container body 2. External air is taken in from the air inlet 4 of the container body 2 2 is heated by the heat generated from the spent nuclear fuel housed in the closed container 11 housed inside 2, and rises inside the container body 12 to flow out from the air outlet 5 to the outside to radiate heat. There is.

The closed container 11 is provided with a container body 12 made of metal such as stainless steel which forms an upright cylindrical body with an open upper end. Inside the container body 12, a plurality of spent nuclear fuels are used. 101 is stored and arranged in an upright state. A shield lid 14, a primary lid 15 and a secondary lid 16 supported by a support member 13 are fitted and arranged in the upper open portion of the container body 12 so as to be horizontally overlapped from the lower side.

The support member 13 is made of a metal such as stainless steel, and a plurality of (for example, four or eight,
8 pieces are prepared here. These plural supporting members 1
3 is a position on the inner peripheral surface of the container body 12 at equal intervals in the circumferential direction of the container body as shown in FIG. 2, and the height at which the respective lids 14 to 16 are arranged is drawn from the upper end of the container body. The support members 13 are horizontally arranged at positions, and the outer peripheral surfaces of the respective support members 13 are welded and fixed to the inner peripheral surface of the peripheral wall portion of the container body 12.

The shielding lid 14 is a circular lid made of metal such as stainless steel, and is used as the spent nuclear fuel 101.
It has the thickness necessary to shield the radiation emitted from the. The shielding lid 14 is inserted into the inside of the container main body 12 from the open upper end, is lowered, and is horizontally placed and supported on the support member 13. The outer peripheral surface of the shielding lid 14 and the container body 1
A gap S exists between the inner peripheral surface of the peripheral wall portion 2 and the inner peripheral surface of the peripheral wall portion 2 as a clearance when the shielding lid 14 is inserted into the container body 12 in water.

The primary lid 15 and the secondary lid 16 are the container body 1
The upper end opening of 2 is sealed, and it is a disk made of metal such as stainless steel. The primary lid 15 and the secondary lid 16 do not need to be inserted into the container body 12 in water, and Since the main body 12 is sealed, the outer peripheral surface comes into contact with the inner peripheral surface of the peripheral wall portion of the container main body 12. The primary lid 15 is inserted into the inside of the upper end opening of the container body 12, lowered, horizontally arranged above the shielding lid 14 and brought into contact with the upper surface thereof, and subjected to welding such as TIG welding by the welding beat 17. The outer peripheral surface is the container body 1
It is joined to the inner peripheral surface of the peripheral wall portion 2. The secondary lid 16 is inserted into the inside of the container main body 12 from the open upper end, is lowered, is horizontally arranged above the primary lid 15, and is brought into contact with the upper surface thereof.
The outer peripheral surface is joined to the inner peripheral surface of the peripheral wall portion of the container body 12 by welding such as TIG welding and a welding beat 18.

The primary lid 15 is fixed to the container body 12 by a lid fixing means. In this embodiment, a rod member, that is, a screw rod 21 is used as the lid fixing means. That is, a plurality of screw holes 22 are formed in the support member 13 side by side in the circumferential direction, and the screw holes 22 are drilled at an appropriate depth from the upper surface of the support member 13 in the vertical direction. A plurality of through holes 23 are formed in the outer peripheral edge portion of the shielding lid 14 side by side in the circumferential direction at the same positions as the screw holes 22 of each support member 13, and the through holes 23 form the upper surface and the lower surface of the shielding lid 14. It is formed so as to penetrate along the vertical direction. A plurality of through holes 24 are formed in the outer peripheral edge portion of the primary lid 15 side by side in the circumferential direction at the same positions as the screw holes 22 of each support member 13. The through holes 24 connect the upper surface and the lower surface of the primary lid 15. It is formed so as to penetrate along the vertical direction, and a large-diameter recess 24a is formed at the upper end.

A bolt is used for the screw rod 21, and the lower end 2
A screw portion 21a is formed on the la and a hexagonal head portion 21b is formed on the upper end. The length of this screw rod 21 is 1
5 and the thickness of the shielding lid 14 are different depending on the screw hole 2 of the supporting member 13.
It is the size obtained by adding the depth of 2. The same number of screw rods 21 as the screw holes 22 of the support member 13 are used.

The screw rod 21 is provided with a through hole 24 in the primary lid 15 and a through hole 2 in the shielding lid 14 from the upper side of the primary lid 15.
3, the threaded portion 21a at the lower end projects to the lower side of the shielding lid 14 and is screwed into the screw hole 22 of the support member 13, and the head portion 21b enters the recess 24a of the primary lid 15. There is. That is, the screw portion 21a is screwed into the screw hole 22.
The lower surface of the head portion 21b firmly presses the lower surface of the concave portion 24a from the upper side by screwing the screw rod 21 into the screw rod 21 and rotating the screw rod 21 in the tightening direction to descend. In other words, the screw rod 21 is fixed to the support member 13 attached to the container body 12 via the shielding lid 14. A plurality of screw rods 21 screwed into the screw holes 22 formed in the support members 13 and attached to the support members 13 disperse and press the outer peripheral portion of the primary lid 15 in the circumferential direction. It is fixed to the support member 13. As a result, the outer peripheral portion of the primary lid 15 has a plurality of screw rods 2 serving as lid fixing means.
It is fixed to the container body 12 with a joint strength equivalent to that in the case of welding by 1 and joining to the container body 12.

Therefore, a large welding bead is provided between the outer peripheral surface of the primary lid 15 and the inner peripheral surface of the container body 12 in order to join the primary lid 15 to the container body 12 with the required strength as in the prior art. It is not necessary to perform welding to form (for example, 16 mm), and it is only necessary to fill the gap between the outer peripheral surface of the primary lid 15 and the inner peripheral surface of the container body 12 by sealing them. Welds have been applied to form small weld beats 17. That is, the thickness of this welding beat 17
T is about 2 mm, which is a very small value as compared with the conventional welding bead thickness of 16 mm for joining and fixing welding.

Therefore, the primary lid 15 is fixed to the container body 12 by the lid fixing means, and the primary lid 15 for the container body 12 is fixed.
The primary lid 15 is attached to the container body 12 to secure the fixing strength of the container.
It is possible to reduce the thickness of the weld beet to be weld-bonded to the container body 12 as compared with the conventional case, and it is possible to suppress the deformation of the container body 12 when the primary lid 15 is weld-bonded to the container body 12. Then, the secondary lid 16 is attached to the container body 12
It is not necessary to perform mechanical processing on the container body 12 when welding and joining are performed, and it is possible to suppress the occurrence of economic loss due to the mechanical processing.

In this embodiment, as the lid fixing means, a plurality of bolt type screw rods 21 penetrating the primary lid 15 and the shielding lid 14 and fixed to the respective support members 13 are used to surround the shielding lid 14. It can be reliably fixed to the container body 12 over the entire direction.

The screw rod 21 has the screw portion 21a screwed into the screw hole 22 of each support member 13 to be mounted.
In addition to this, welding may be applied to each of the support members 13 so that the support members 13 are more firmly attached. Further, a bar material having no screw is used as the lid fixing means in place of the screw bar, a hole having no screw is formed in each support member 13, and the bar material is inserted into the hole and welded and joined. Is also good. Further, the screw rod 21 may not be provided with a hexagonal head portion 21b similar to a bolt, and instead, a screw portion may be formed at a position of the head portion and a nut may be screwed to hold the primary lid 15.

Further, in order to improve the drainage at the contact portion between the shield lid 14 and the primary lid 15, a large number of grooves 14a are formed along the radial direction on the upper surface of the shield lid 14, and the primary lid 15 is formed.
In order to improve drainage at the contact portion between the secondary lid 16 and the secondary lid 16, a large number of grooves 15a extending in the radial direction and a large number of grooves 15b extending in the circumferential direction are formed on the upper surface of the primary lid 15.

In this embodiment, an assembling method for inserting the shielding lid 14 into the container body 12 will be described with reference to FIG. FIG. 7 shows this assembling method.

When the shield lid 14 is inserted into the inside of the container body 12 from the upper end open portion, the guide rods 31 are prepared in a number corresponding to the number of the support members 13, for example. These guide rods 31 are made of metal such as stainless steel, and have a length equal to or greater than the height from the support member 13 to the open upper end of the container body 12 plus the thickness of the shielding lid 14. ing. A threaded portion 31a is formed at one end of each of the guide rods 31. These guide rods 31 should be vertical and the container body 1
2 is inserted into the inside from the upper end open portion, and the screw portion 31a is screwed into the screw hole 22 and attached to the support member 13. In this way, each guide rod 31 is set upright in each screw hole 22 of each support member 13. In this case, the upper portion of each guide rod 31a projects upward from the upper end open portion of the container body 12.

Next, in this state, the container main body 12 is submerged inside the pool in which water is stored. The spent nuclear fuel is inserted into the container body 12. Then, the container body 1
2 is raised until the upper portion of the guide rod 13 projects above the water surface, the shielding lid 14 is positioned horizontally above the container body 12, and then descends and is formed on the outer peripheral portion of the shielding lid 14. The support member 1 of the container body 12 is provided in the through hole 23.
The upper part of each guide rod 31 attached to 2 is inserted. Accordingly, the shielding lid 14 is positioned right above the upper end opening of the container body 12 at a position where the outer peripheral surface does not collide with the inner peripheral surface of the peripheral wall portion of the container body 12. When the shield lid 14 is lowered in this state, the shield lid 14 is inserted into each guide rod 31 through each through hole 23.
Being guided vertically to the container body 12, the container cover 12 is inserted into the container body 12 without colliding with the upper end open portion thereof, and the shielding lid 14 descends without colliding with the inner peripheral surface of the container body 12. Reach the upper surface of each support member 13. afterwards,
Each guide rod 31 is removed from the screw hole 22 of the support member 13.
As shown in FIGS. 3 and 7, when the outer peripheral edge of the lower end surface of the shielding lid 14 is cut off to form a tapered portion 32 that widens toward the upper side, when the shielding lid 14 is inserted into the container body 12, the shielding lid 14 is inserted. The outer peripheral portion of the lower end surface of 14 is the container body 1
In this assembling method, the shielding lid 14 can be easily and stably inserted into the container body 12 without being damaged by colliding with the upper end open portion of 2, and the shielding lid 14 is vertically penetrated. Since the shielding lid 14 is lowered while being guided through the plural holes 22 through the guide rod 31 and inserted into the container body 12 from the upper end opening portion, the shielding lid 14 and the container body 12 are
Even if the size of the gap S between and is smaller than that of the conventional case, the shielding lid 14 is easily and accurately aligned with the upper end opening portion of the container body 12 in water without collision with the container body 12. It is possible to insert and arrange inside 12,
The size of the gap S between the shielding lid 14 and the peripheral wall portion of the container body 12 can be made smaller than in the conventional case. For this reason, the size of the diameter of the shielding lid 14 is set so that the size of the gap S between the outer peripheral surface of the shielding lid 14 and the inner peripheral surface of the peripheral wall portion of the container body 12 becomes smaller than in the conventional case. Therefore, the deformation of the container body 12 when the outer container 1 is tumbled can be suppressed to a small level, and the container body 12 and the primary lid 15 and the secondary lid 16 can be joined by welding in a good form. In addition,
In this assembling method, the screw hole 22 of the support member 13 and the shield lid 14 are configured to fix the primary lid 15 to the container body 12.
Of the through holes 23 are effectively used.

FIG. 4 is a sectional view showing another embodiment of the structure for fixing the shield lid 14 to the container body 12. In this embodiment, as the lid fixing means, the screw portion 41 is formed on the outer peripheral surface of the primary lid 15, and the screw portion 41 formed on the outer peripheral surface of the primary lid 15 at the primary lid disposition position on the inner peripheral surface of the peripheral wall portion of the container body 12. Is formed with a threaded portion 42. That is, by inserting the primary lid 15 into the inside of the container body 12 from the upper end open portion and screwing the screw portion 41 into the screw portion 42 of the container body 12 while rotating, the primary lid 1
5 can be fixed to the container body 12.

In this embodiment, since the screw structure is adopted as the lid fixing means, the primary lid 15 can be fixed to the container body 12 by a simple operation of rotating the primary lid 15 in the circumferential direction. . As shown in FIG. 4, the threaded portion 42 may be formed continuously from the open upper end portion of the container body 12. In this case, the outer peripheral portion of the secondary lid 16 is also threaded to be screwed. .

FIG. 5 and FIG. 6 show that the shielding lid 14 is used for the container body 1.
FIG. 5 is a plan view and FIG. 6 is a cross-sectional view showing another embodiment relating to the structure of fixing to FIG. In this embodiment, a plurality of engaging claws 51 are formed on the outer peripheral edge of the primary lid 15 at intervals in the circumferential direction, and the primary lid placement position (the same height position) on the inner circumferential surface of the peripheral wall portion of the container body 12 is positioned. The engaging claws 51 of the primary lid 15 are formed with the same number of engaging groove portions 52 as the engaging claws 51 that are engageably and disengageably engaged with each other in the circumferential direction. The engaging claws 51 of the primary lid 15 are arcuately drawn with a radius larger than the outer peripheral surface of the primary lid 15 with the central axis of the primary lid 15 as the center, and have the same circumferential length and are equally spaced. Is formed. The engagement groove portion 52 of the container body 12 has a diameter with which the engagement claw 51 of the primary lid 15 can engage with the center axis of the container body 12 as a center. The dimensions are such that the engaging claws 51 of the primary lid 15 can be inserted. In addition,
The inner peripheral surface of the peripheral wall portion of the container body 12 is a cylinder whose portion from the upper end opening portion to the engaging groove portion 52 is drawn with the same diameter as the engaging groove portion 52, and the portion below the engaging groove portion 52 is the primary lid 15. Has the same diameter as the outer peripheral surface. The outer peripheral surface of the shielding lid 14 has the same diameter as the primary lid 15, and the secondary lid 16 has the same diameter as the engaging claws 51 of the primary lid 15.

When the primary lid 15 is assembled into the container body 12, the primary lid 15 is inserted into the container body 12 from the upper end open portion and lowered, so that the engaging claws 51 of the primary lid 15 are inserted into the container body 12. 12 are made to fit into the gaps between the engaging grooves 52, and then the primary lid 15 is rotated to displace the engaging claws 51 in the circumferential direction so as to enter the inside of the engaging grooves 52 of the container body 12. Engage. Thereby, the primary lid 15 is fixed to the container body 12.

In this embodiment, since the screw structure is adopted as the lid fixing means, the primary lid 15 can be fixed to the container body 12 by a simple operation of rotating the primary lid 15 in the circumferential direction. .

The present invention is not limited to the above-mentioned embodiments, but can be modified in various ways.

[0038]

According to the airtight container for radioactive substances of the first aspect of the present invention, since the primary lid is fixed to the container body by the lid fixing means, the fixing strength of the primary lid to the container body is secured.
The weld bead thickness for welding and joining the primary lid to the container body can be made smaller than before, and deformation of the container body when welding and joining the primary lid to the container body is prevented, A welded joint with the lid can be obtained in good form.

According to the second aspect of the present invention, as the lid fixing means, a plurality of bolt type rod members which penetrate the primary lid and the shielding lid and are fixed to the supporting member are used, and the shielding lid is provided in the entire circumferential direction. It can be securely fixed to the container body.

According to the third aspect of the present invention, since the screw structure is adopted as the lid fixing means, the primary lid can be fixed to the container body by a simple operation of rotating the primary lid in the circumferential direction.

According to the method for assembling the closed container for radioactive substances of the fourth aspect of the present invention, the shield lid is lowered while guiding the shield lid by using the plurality of guide rods, and the shield lid is inserted into the interior of the container body from the upper end opening. Therefore, even if the size of the gap between the shielding lid and the container body is made smaller than in the conventional case, the shielding lid can be easily and accurately aligned with the upper end opening of the container body and collide with the container body in water. It is possible to insert and arrange it inside the container body Io without using it, and it is possible to make the gap between the shielding lid and the container body smaller than before, so that the deformation of the container body when the external container falls The size of the container body can be suppressed to a small value, and the joining of the container body and the lid by welding can be obtained in a good form.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a closed container according to an embodiment of the present invention.

FIG. 2 is a plan view showing the arrangement of support members in the closed container of the same embodiment.

FIG. 3 is an enlarged cross-sectional view showing a lid joint portion in the closed container of the same embodiment.

FIG. 4 is a sectional view showing a closed container according to another embodiment.

FIG. 5 is a plan view showing a lid joint portion in a closed container according to another embodiment.

FIG. 6 is a cross-sectional view showing a lid joint portion in a closed container according to another embodiment.

FIG. 7 is an explanatory view showing a method of assembling the closed container.

[Explanation of symbols]

1 ... External container 2 ... container body 3 ... Lid 11 ... Airtight container 12 ... Container body 13 ... Support member 14 ... Shielding lid 15 ... Primary lid 16 ... Secondary lid 17 ... Welding beet 18 ... Welding beet 21 ... Screw rod (lid fixing means) 22 ... Screw hole 23 ... Through hole 24 ... Through hole 31 ... Guide rod 41 ... screw part (lid fixing means) 42 ... screw part (lid fixing means) 51 ... Engaging claw (lid fixing means) 52 ... Engaging groove claw (lid fixing means)

Continued front page    (72) Inventor Kazuo Murakami             1-1 1-1 Wadasaki-cho, Hyogo-ku, Kobe-shi, Hyogo             No. Mitsubishi Heavy Industries, Ltd.Kobe Shipyard (72) Inventor Iwaji Abe             1-1 1-1 Wadasaki-cho, Hyogo-ku, Kobe-shi, Hyogo             No. Mitsubishi Heavy Industries, Ltd.Kobe Shipyard (72) Inventor Mitsuhiro Irino             2-19-13 Takanawa, Minato-ku, Tokyo Ryoyu Co., Ltd.             Within system technology (72) Inventor Masahiro Okada             7-1-14 Wadamiyadori, Hyogo-ku, Kobe-shi, Hyogo             Issue Nishiryo Engineering Co., Ltd.

Claims (4)

[Claims] 1. A container main body made of a metal having an open upper end and containing a radioactive substance therein, a support member attached to an inner peripheral surface of a peripheral wall portion of the container main body, and a container disposed inside the container main body. A shielding lid placed and supported on the support member,
A primary lid that is located above the shielding lid and that is disposed inside the container body and that is joined by welding to the container body; and a container that is located above the primary lid and that is disposed in the container body. A closed container for radioactive material, comprising: a secondary lid joined by welding to a main body; and a lid fixing means for fixing the primary lid to the container main body. 2. The lid fixing means is inserted from the peripheral portion of the primary lid through the peripheral portion of the shielding lid in the vertical direction, the lower end portion is fixed to the support member, and the upper end portion is the primary portion. The sealed container for radioactive material according to claim 1, wherein the sealed container is a rod member for pressing a lid. 3. The lid fixing means has a screw portion formed on an inner surface of the container body, and a screw portion formed on an outer peripheral surface of the primary lid and screwed to the screw portion. The airtight container for radioactive substances according to claim 1. 4. A container main body made of metal having an open upper end and containing a radioactive substance therein, a support member attached to an inner peripheral surface of a peripheral wall portion of the container main body, and a container disposed inside the container main body. A shielding lid placed and supported on the support member,
In a closed container, which is located above the shielding lid and is disposed inside the container body, and which is joined by welding the container body, the shielding lid is provided inside from an upper end opening portion of the container body. When it is inserted into the container body, a plurality of guide bars that are detachably attached to the support member and project upward from the upper end opening portion of the container body are provided upright inside the container body, and penetrate the shield cover in the vertical direction. Assembling of a closed container for radioactive material, characterized in that the shielding lid is lowered while being guided through the plurality of holes formed through the guide rod and inserted into the inside of the container main body from the upper end opening portion of the container main body. Method.