JP2005283135A - Basket for recycle fuel assembly storage, and recycle fuel assembly storage container - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To manufacture efficiently even when a material which is difficult to be extruded such as B-Al material is used. <P>SOLUTION: This basket 1a for recycle fuel assembly storage has a constitution equipped with square pipe steels 3 arrayed in the lattice shape for storing the recycle fuel assemblies inside, square pipe steels 20 for spacers arranged between each square pipe steel 3 for storage and abutting on the outside surfaces of the square pipe steels 3 for storage, and support members 10 with square-shaped sections arranged on the square part outside of the square pipe steels 3 for storage. The support member 10 is provided with a through hole penetrating in the longitudinal direction, and fulfills a flux trapping function together with the square pipe steel 20 for the spacer. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a recycled fuel assembly storage basket for storing a recycled fuel assembly, and more specifically, a recycled fuel assembly that can be efficiently manufactured even when a hard-extrusion material such as a B-Al material is used. The present invention relates to a storage basket and a radioactive substance storage container.

  A nuclear fuel assembly at the end of the nuclear fuel cycle that cannot be used after combustion is called a recycled fuel assembly. Since the recycled fuel assembly contains a highly radioactive substance such as FP and needs to be cooled thermally, it is cooled in a cooling pit of a nuclear power plant for a predetermined period (5 to 15 years). Then, it is stored in a cask that is a shielding container, and is transported and stored in a reprocessing facility by a vehicle or ship. When the recycled fuel assembly is stored in the cask, a holding frame having a lattice-like cross section called a recycled fuel assembly storage basket is used. The recycled fuel assemblies are inserted one by one into cells that are a plurality of storage spaces formed in the recycled fuel assembly storage basket. This ensures an appropriate holding force against vibration during transportation. As a conventional example of such a cask, various types of cask are disclosed in, for example, Patent Document 1 and Non-Patent Document 1.

Japanese Patent Laid-Open No. 64-086098 "Nuclear Nuclear Eye" (issued April 1, 1998: Nikkan Kogyo Publishing Production)

  By the way, when transporting and storing the recycled fuel assembly, the recycled fuel assembly is brought close to and stored in the basket. For this reason, the recycled fuel assembly storage basket is required to have a function of absorbing neutrons (hereinafter referred to as neutron absorption capability) so that the stored recycled fuel assembly does not reach criticality. In order to achieve this subcritical function, in recent years, the basket is often made of a B-Al material. In this case, a member constituting the basket may be manufactured by extruding a B-Al powder sintered material. The member manufactured in this manner exhibits excellent mechanical strength and neutron absorption ability because B and the like are uniformly dispersed in the base material. However, since such a material has high hardness B or B compound dispersed in an Al base material, the extrusion die is likely to be worn.

  In addition, since fuel for PWR (Pressurized Water Reactor) has a high burnup, the recycle fuel assembly storage basket that stores the recycle fuel assembly is required to have a function to reliably prevent the criticality of the fuel. The For this reason, the member used for the recycle fuel assembly storage basket for storing the PWR recycle fuel assembly has a flux trap on its wall surface. Since such a member has a large surface area, the load on the extrusion die is increased accordingly. As a result, the wear of the extrusion die becomes severe, and the production efficiency is reduced. Moreover, since the surface area of the member having a complicated shape increases, the extrusion pressure also increases, and the production by extrusion molding is inefficient. Furthermore, since B-Al material containing B or B compound with high hardness is a difficult-to-cut material, tool wear is severe and machining is difficult. For this reason, when additional processing after extrusion molding is required, the production efficiency was poor.

  Therefore, the present invention has been made in view of the above, and a recycled fuel assembly storage basket and a recycled fuel assembly that can be efficiently manufactured even when a difficult-to-extrusion material such as a B-Al material is used. An object is to provide a body storage container.

  In order to solve the above-described problems and achieve the object, a recycled fuel assembly storage basket according to the present invention is arranged in a lattice shape, and the storage square pipe for storing the recycled fuel assembly therein, And a spacer disposed between the storage square pipes.

  The recycled fuel assembly storage basket is configured by combining a storage square pipe for storing the recycled fuel assembly and a spacer disposed between the storage square pipes. Thereby, since the dimension of each member which comprises the recycle fuel assembly accommodation basket can be made small, even if it is a difficult extrusion material like a B-Al material, extrusion pressure can be suppressed low and it can manufacture efficiently.

  The basket for storing recycled fuel assemblies according to the present invention is arranged in a lattice pattern, and is disposed between the storage square pipes for storing the recycled fuel assemblies therein and between the storage square pipes. And a spacer square pipe abutting on an outer surface of the storage square pipe, and a support member having a quadrangular cross section disposed outside the corner of the storage square pipe.

  In this recycled fuel assembly storage basket, the square pipes for storing the recycled fuel assemblies are arranged in a lattice pattern, and the spacer square pipe and the support member for the storage square pipe are disposed between the storage square pipes. Deploy. With such a configuration, the dimensions of the individual members constituting the recycled fuel assembly storage basket can be reduced. Therefore, even a difficult-to-extrusion material such as a B-Al material can be efficiently manufactured with a low extrusion pressure. . In addition, since all the constituent members of the recycled fuel assembly storage basket can be manufactured by extrusion molding, cutting after molding is unnecessary. As a result, when a material containing boron or boron compound with high hardness is used, the labor required for cutting can be omitted, so even difficult-to-cut materials such as B-Al materials can be manufactured efficiently with low extrusion pressure. it can.

  The recycled fuel assembly storage basket according to the present invention is characterized in that in the recycled fuel assembly storage basket, the support member is formed with a through hole extending in the longitudinal direction.

  Since the recycled fuel assembly storage basket has the configuration of the recycled fuel assembly storage basket, the recycled fuel assembly storage basket exhibits the functions and effects exhibited by the recycled fuel assembly storage basket. Further, in this recycled fuel assembly storage basket, when the basket is configured, a support member disposed outside the corner portion of the storage square pipe is provided with a through hole extending in the longitudinal direction. As a result, the through hole functions as a flux trap that shields neutrons, thereby improving the subcritical performance of the basket according to the present invention.

  The recycled fuel assembly storage basket according to the present invention is characterized in that in the recycled fuel assembly storage basket, the support member and the spacer square pipe are connected.

  Since the recycled fuel assembly storage basket has the configuration of the recycled fuel assembly storage basket, the recycled fuel assembly storage basket exhibits the functions and effects exhibited by the recycled fuel assembly storage basket. Further, the recycled fuel assembly storage basket connects the support member disposed outside the corner portion of the storage square pipe and the spacer square pipe disposed between the storage square pipes. As a result, the square pipe for spacer and the support member are firmly coupled, so that the entire basket for storing recycled fuel assemblies has a robust structure. As a result, durability against an impact force when the cask storing the basket inside falls is improved.

  In the recycled fuel assembly storage basket according to the present invention, in the recycled fuel assembly storage basket, a concave portion that extends in the longitudinal direction of the support member is formed outside the corner portion of the support member. A corner outer side of the storage square pipe is fitted into the recess.

  Since the recycled fuel assembly storage basket has the configuration of the recycled fuel assembly storage basket, the recycled fuel assembly storage basket exhibits the functions and effects exhibited by the recycled fuel assembly storage basket. Further, the recycled fuel assembly storage basket includes a recess in the longitudinal direction outside the corner of the support member, and the recess and the corner outside of the storage square pipe are fitted together. Thereby, when the basket is assembled, the support member and the storage square pipe can be positioned, so that the basket can be easily assembled.

  The recycled fuel assembly storage basket according to the next aspect of the present invention is characterized in that, in the recycled fuel assembly storage basket, the square pipe for spacer projects a long side end portion.

  Since the recycled fuel assembly storage basket has the configuration of the recycled fuel assembly storage basket, the recycled fuel assembly storage basket exhibits the functions and effects exhibited by the recycled fuel assembly storage basket. Further, the recycled fuel assembly storage basket includes a projecting portion at the longitudinal end of the spacer square pipe. As a result, a flux trap is formed in the vicinity of the support member, so that the subcritical function of the recycled fuel assembly storage basket can be further improved.

  In the recycled fuel assembly storage basket according to the present invention, in the recycled fuel assembly storage basket, the spacer square pipe has a short portion in a cross section perpendicular to the longitudinal direction of the spacer square pipe. A rib parallel to the side is provided.

  Since the recycled fuel assembly storage basket has the configuration of the recycled fuel assembly storage basket, the recycled fuel assembly storage basket exhibits the functions and effects exhibited by the recycled fuel assembly storage basket. Further, the recycled fuel assembly storage basket includes a rib inside the square pipe for spacer. As a result, the strength of the spacer square pipe is improved, so that the basket as a whole has a robust structure. Further, since the area of the heat passage is increased by the rib, the heat transfer performance of the decay heat of the recycled fuel assembly is improved.

  A basket for storing a recycled fuel assembly according to the present invention is arranged in a lattice shape, a storage square pipe for storing the recycled fuel assembly therein, a flat plate, both surfaces of the flat plate, and the flat plate. A spacer member configured to include a rib provided in a direction orthogonal to the rib, and the rib abuts against an outer surface of the storage square pipe, and the spacer member is disposed between the storage square pipes. It is arrange | positioned between.

  The recycled fuel assembly storage basket is configured by combining a storage square pipe for storing the recycled fuel assembly and a spacer member disposed between the storage square pipes. Thereby, since the dimension of each member which comprises the basket for recycled fuel assembly accommodation can be made small, even if it is a difficult extrusion material like a B-Al material, it can suppress efficiently and can manufacture efficiently. In addition, since this spacer member does not have a hollow pipe structure, a core is not required when the spacer member is extruded. As a result, it can manufacture more efficiently.

  The recycled fuel assembly storage basket according to the present invention is arranged in a lattice shape, storage square pipes for storing the recycled fuel assemblies therein, and first flat plate portions arranged in parallel and alternately, The first ribs are orthogonal to the first flat plate portion and include first ribs that connect the first flat plate portions that are alternately arranged, and are arranged in a specific direction between the storage square pipes. First spacer members that are arranged, second flat plate portions that are arranged in parallel and alternately, and second ribs that are orthogonal to the second flat plate portions and that connect the alternately arranged second flat plate portions. A second spacer member disposed between the storage square pipes so that the second flat plate portion is orthogonal to the first flat plate portion of the first spacer member, and The 1 flat plate portion and the second flat plate portion are The long side length in the cross section perpendicular to the axis of the second spacer member is in contact with the outer surface of the storage square pipe and is longer than the long side length in the cross section perpendicular to the axial direction of the first spacer member. It is large.

  The recycled fuel assembly storage basket is configured by combining a storage square pipe for storing the recycled fuel assembly, and first and second spacer members disposed between the storage square pipes. Thereby, since the dimension of each member which comprises the basket for recycled fuel assembly accommodation can be made small, even if it is a difficult extrusion material like a B-Al material, it can suppress efficiently and can manufacture efficiently. Further, since the first and second spacer members do not have a hollow pipe structure, a core is not required when the spacer members are extruded. This makes manufacturing more efficient.

  The recycle fuel assembly storage basket according to the present invention includes a storage square pipe for storing the recycle fuel assembly in the recycle fuel assembly storage basket, which is arranged in a lattice shape and stores the recycle fuel assembly therein. A plate-like spacer member that is disposed between the square pipes and has a through-hole inside, and the long-side end portions are formed in a step shape, and the long-side end portions of the spacer members are It is characterized by being combined.

  The recycled fuel assembly storage basket is configured by combining a storage square pipe for storing the recycled fuel assembly and a plate-like spacer member disposed between the storage square pipes. Thereby, since the dimension of each member which comprises the basket for recycled fuel assembly accommodation can be made small, even if it is a difficult extrusion material like a B-Al material, it can suppress efficiently and can manufacture efficiently. Moreover, since this plate-shaped spacer member combines the long side edge parts formed in the step shape, it can position spacer members correctly. Further, since the contact area of the long side end of the spacer member is increased, the impact force when the cask storing the basket is dropped can be transmitted efficiently, and a robust basket can be obtained.

  A recycled fuel assembly storage basket according to the present invention includes a storage square pipe for storing the recycled fuel assembly therein, and a cross-section perpendicular to the longitudinal direction having a cross shape, and the longitudinal direction in the interior. A cross member in which a hole toward the surface is formed, and a long side end of the cross member are butted together to form a lattice-like space for arranging the storage square pipe, and the lattice-like space is formed in the lattice-like space. The storage square pipe is arranged.

  This recycled fuel assembly storage basket is configured by combining a storage square pipe for storing the recycled fuel assembly and a cross member having a cross-shaped cross section disposed between the storage square pipes. Thereby, since the dimension of each member which comprises the basket for recycled fuel assembly accommodation can be made small, even if it is a difficult extrusion material like a B-Al material, it can suppress efficiently and can manufacture efficiently.

  The recycled fuel assembly storage basket according to the next aspect of the present invention is the recycled fuel assembly storage basket, wherein the cross member includes the long-side end portion in which a concave portion is formed and the convex portion. A long side end portion, and the concave portion and the convex portion are combined.

  Since the recycled fuel assembly storage basket has the configuration of the recycled fuel assembly storage basket, the recycled fuel assembly storage basket exhibits the functions and effects exhibited by the recycled fuel assembly storage basket. Furthermore, since this recycle fuel assembly storage basket is combined with a concave portion and a convex portion formed at the end portion on the long side, the positioning accuracy of the cross member is improved, and the displacement between the cross members can be suppressed. The basket can be easily assembled. Moreover, since a recessed part and a convex part are combined, the contact area of long side side edge parts becomes large. Thereby, since heat conduction between cross members improves, heat transfer performance improves also as the whole basket.

  In the recycled fuel assembly storage basket according to the next aspect of the present invention, in the recycled fuel assembly storage basket, the cross member includes a long side end portion in which a cross section perpendicular to the longitudinal direction is formed in a step shape. The long side end portions are combined with each other.

  Since the recycled fuel assembly storage basket has the configuration of the recycled fuel assembly storage basket, the recycled fuel assembly storage basket exhibits the functions and effects exhibited by the recycled fuel assembly storage basket. Furthermore, in this recycled fuel assembly storage basket, since the long side end portions formed in a stepped cross section are combined, the positioning accuracy of the cross members is improved, and the displacement of the cross members can be suppressed. The basket can be easily assembled. Further, since the long-side end portions having a step-like cross section are combined, the contact area between the long-side end portions increases. Thereby, since heat conduction between cross members improves, heat transfer performance improves also as the whole basket.

  A recycled fuel assembly storage basket according to the present invention includes a recycled fuel assembly storage in which square pipes for storing the recycled fuel assemblies are arranged in a space formed by alternately stacking square pipe-like members in a plurality of stages. A first square pipe-like member arranged in the same direction every other step, and a first square pipe-like member arranged in the same direction every other step and stacked perpendicularly to the first square pipe-like member. A square pipe-shaped member, and a storage square pipe that is disposed in a space surrounded by the first square pipe-shaped member and the second square pipe-shaped member and accommodates a recycled fuel assembly therein. At least one of the first square pipe-shaped member and the second square pipe-shaped member is arranged such that its tube axis is inclined with respect to the bottom surface of the recycled fuel assembly storage basket. Characterized by location.

  The recycled fuel assembly storage basket is configured by combining a storage square pipe for storing the recycled fuel assembly, a first square pipe member, and a second square pipe member. Accordingly, the size of each member constituting the recycled fuel assembly storage basket can be reduced, and each member can be configured in a simple square pipe shape. As a result, even a difficult-to-extrusion material such as a B-Al material can be efficiently manufactured with a low extrusion pressure. Furthermore, since at least one of the first square pipe-shaped member or the second square pipe-shaped member is arranged so that the tube axis thereof is inclined with respect to the bottom surface of the basket, the drainage performance of the basket is improved.

  A recycled fuel assembly storage basket according to the present invention is a recycled fuel assembly storage basket configured by combining plate-like members, a notch is formed at the end on the long side, and the longitudinal direction The plate-like members are stacked in a plurality of stages by combining plate-like members having through-holes penetrating through the notches and combining the notches with each other, and the plate-like member is a bottom surface of the recycled fuel assembly storage basket. The recycled fuel assembly is housed in a lattice-like space surrounded by the plurality of plate-like members.

  The recycled fuel assembly storage basket is configured by combining and laminating plate members, and the plate members are inclined with respect to the bottom surface of the recycled fuel assembly storage basket. Thereby, water and air remaining inside the plate-like member can be easily discharged.

  The recycled fuel assembly storage basket according to the next aspect of the present invention is the recycled fuel assembly storage basket, wherein the long side end of the first square pipe-shaped member or the long side of the second square pipe-shaped member is used. A drainage passage is formed in at least one of the side end portions.

  Since the recycled fuel assembly storage basket has the configuration of the recycled fuel assembly storage basket, the recycled fuel assembly storage basket exhibits the functions and effects exhibited by the recycled fuel assembly storage basket. Further, in this recycled fuel assembly storage basket, a drainage passage is formed in at least one of the long side end of the first square pipe member or the long side end of the second square pipe member. . This drainage passage further improves the drainage performance of the basket. In addition, it is preferable to form the drainage passage at least on the long side end located on the upper side in the vertical direction.

  The recycled fuel assembly storage basket according to the next aspect of the present invention is the above-mentioned recycled fuel assembly storage basket, wherein a storage square pipe for storing the recycled fuel assembly is formed, and a drain passage is formed at the end on the long side. A square pipe-like member, and stacking the square pipe-like member alternately in a plurality of stages in an orthogonal manner, and arranging the storage square pipe in a lattice-like space surrounded by the square pipe-like member. Features.

  The recycled fuel assembly storage basket is configured by combining a storage square pipe for storing the recycled fuel assembly and a square pipe member having a drainage passage formed at the end on the long side. Accordingly, the size of each member constituting the recycled fuel assembly storage basket can be reduced, and each member can be configured in a simple square pipe shape. As a result, even a difficult-to-extrusion material such as a B-Al material can be efficiently manufactured with a low extrusion pressure. Further, since the drainage passage is formed at the long side end of the square pipe member, it is not necessary to process the drain hole in the square pipe member. Thereby, even if it is a difficult-to-cut material such as a B-Al material, the cutting process is not necessary, so that the manufacturing becomes efficient.

  The recycle fuel assembly storage basket according to the present invention is the recycle fuel assembly storage basket, wherein the storage square pipe, the spacer, the spacer square pipe, the support member, and the like, the recycled fuel assembly. The constituent member of the body storage basket is an aluminum alloy containing boron or a boron compound, or an aluminum alloy, and at least one of the constituent members is an aluminum alloy containing boron or a boron compound. .

Since the storage basket has a subcritical function, a sufficient subcritical function can be achieved when a PWR fuel having a high burnup is stored. Here, boron is B ¹⁰ that contributes to neutron absorption. Here, the constituent members of the recycled fuel assembly storage basket are: storage square pipe, spacer, spacer square pipe, support member, spacer member, first spacer member, second spacer member, cross member, first square pipe. A member constituting a recycled fuel assembly storage basket, such as a shaped member, a second square pipe-like member, and a square pipe-like member.

  A recycle fuel assembly storage container according to the present invention includes a trunk having an opening and a cavity, a lid attached to the opening and sealing the cavity, and the recycling fuel container being disposed in the cavity. And a fuel assembly storage basket.

  Since this recycled fuel assembly storage container includes the recycled fuel assembly storage basket, it can be efficiently manufactured even if the basket is made of a difficult-to-extrusion material such as a B-Al material.

  The recycled fuel assembly storage basket and the recycled fuel assembly storage container according to the present invention have an effect that they can be efficiently manufactured even when a difficult-to-extrusion material such as a B-Al material is used.

  Hereinafter, the present invention will be described in detail with reference to the drawings. The present invention is not limited to the best mode for carrying out the invention. In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art or that are substantially the same. The recycled fuel assembly storage basket described below is mainly used for transport and storage cask, but is not limited to this. For example, it can be used as a concrete cask for storage, or a rack of a canister or a recycled fuel assembly storage pool. Hereinafter, the recycled fuel assembly storage basket is abbreviated as a basket as necessary.

  The recycled fuel assembly storage basket according to the first embodiment is arranged in a lattice pattern, and includes a storage square pipe for storing the recycled fuel assembly therein, abutting against an outer surface of the storage square pipe, and storage. A square pipe for spacers disposed between the square pipes for use, and a support member having a quadrangular cross section that is disposed outside the corners of the square pipes for storage and combined with the square pipes for spacers. There are features. In the first embodiment, the spacer square pipe and the support member function as spacers for the storage square pipe.

  FIG. 1 is a plan view illustrating a part of a recycled fuel assembly storage basket according to the first embodiment. In this basket 1 a, storage square pipes 3 are arranged in a lattice shape, and a recycled fuel assembly is stored inside the storage square pipe 3. Between the storage square pipes 3 arranged in a lattice shape, a spacer square pipe 20 is arranged, and a support member 10 is arranged outside the corner of the storage square pipe 3.

FIGS. 2-1 and 2-2 are explanatory views showing a storage square pipe for storing the recycled fuel assembly. Accommodating square pipes 3 for accommodating the recycled fuel assemblies therein, the length in the tube axis Zp direction is L _1, the length is the length substantially the same as the length of the recycled fuel assemblies. The storage square pipe 3 has a substantially square cross-sectional shape perpendicular to the tube axis Zp direction, the length of one side thereof is l ₁ , and the wall thickness is t. The dimension of the storage square pipe 3 in the cross section perpendicular to the tube axis Zp direction is (l ₁ −2 × t), and this dimension is set to be slightly larger than the outer dimension of the recycled fuel assembly. The storage square pipe 3 is made of an Al (aluminum) material containing B ¹⁰ (boron) (hereinafter referred to as a B-Al material) in order to ensure a subcritical function and reduce the weight. For example, it can be manufactured by hot extruding a billet of B-Al manufactured by powder metallurgy.

FIGS. 3-1 to 3-3 are explanatory views illustrating the support member according to the first embodiment. As shown in these drawings, the length of the support member 10 in the tube axis Zm (corresponding to the longitudinal direction in this example) is L ₂ , and this length is in the tube axis Zp direction of the storage square pipe 3. The length is substantially the same as the length L ₁ at. On the corner outer side 10 co of the support member 10, a recess is formed in the direction of the tube axis Zm of the support member 10. And when comprising the basket 1a, as shown in FIG. 1, it combines with the corner | angular part outer side 3co of the storage square pipe 3. As shown in FIG. With this configuration, the force in the direction orthogonal to the tube axis Zp of the storage square pipe 3 is transmitted to the adjacent storage square pipe 3 via the support member 10. According to this configuration, particularly when the basket 1a is stored in the transport cask of the recycled fuel assembly, the impact force generated when the cask falls can be effectively received. Further, when the basket 1a is assembled, the corner portion outside 10co of the support member 10 and the corner portion outside 3co of the storage corner pipe 3 can be combined to position each other, so that the assembly is facilitated.

  As shown in FIGS. 3-1 to 3-3, the support member 10 is provided with a through-hole 10h having a diameter d penetrating in the tube axis Zm direction (corresponding to the longitudinal direction in this example). When the basket 1a is assembled, the through-hole 10h functions as a flux trap that ensures the subcriticality of the recycled fuel assembly stored in the storage square pipe 3 adjacent in the oblique direction (FIG. 1). Thereby, when a PWR fuel with a high burnup is stored, a sufficient subcritical function can be achieved. The support member 10 is preferably manufactured from a B—Al material. Even when the support member is manufactured with a material to which boron is not added, a neutron shielding material may be inserted or filled into the through hole 10h. Examples of such a neutron shielding material include cadmium, hafnium, rare earth elements, etc. in addition to the B-Al material. Note that when a rare earth element is used, an oxide such as europium, dysprosium, samarium, or gadolinium can be used.

In Example 1, the depth of the recess formed in the corner outside 10co of the support member 10 is t _1. This size is not particularly limited and can be appropriately changed according to the specifications of the basket 1a. For example, the depth of the recess may be made larger than the wall thickness t _{1 of} the storage square pipe 3 to support the storage square pipe 3 more reliably. Moreover, as shown to FIGS. 3-2, the cross-sectional shape perpendicular | vertical to the tube axis Zm of the supporting member 10 is a shape by which the square corner outer side was dropped. The outer dimension of the cross-sectional shape is l _2, and (l ₂ −2 × t ₁ ) corresponds to the distance between adjacent storage square pipes 3.

  FIGS. 4-1 and FIGS. 4-2 are explanatory drawings which show the square pipe for spacers concerning Example 1. FIGS. As shown in FIGS. 4A and 4B, the spacer square pipe 20 is provided with a through hole 20h penetrating in the tube axis Zs direction. When the basket 1a is assembled, the through hole 20h is a flux trap that ensures the subcriticality of the recycled fuel assembly stored in the storage square pipe 3 adjacent in the direction perpendicular to the outer surface 3s of the storage square pipe 3 It fulfills the function as (Fig. 1). Thereby, when a PWR fuel with a high burnup is stored, a sufficient subcritical function can be achieved. The support member 10 is preferably manufactured from a B—Al material. Even when the support member is manufactured with a material to which boron is not added, a neutron shielding material may be inserted or filled into the through hole 10h. Examples of such a neutron shielding material include cadmium, hafnium, rare earth elements, etc. in addition to the B-Al material. Note that when a rare earth element is used, an oxide such as europium, dysprosium, samarium, or gadolinium can be used.

The length of the spacer square pipe 20 in the tube axis Zs direction is L _3, which is the length L ₁ of the storage square pipe 3 in the tube axis Zp direction and the length of the support member 10 in the tube axis Zm direction. it is approximately the same length as the L _2. In Example 1, the thickness of the spacer square pipe 20 is t ₂ , and the thickness t ₂ can be arbitrarily changed according to the specifications of the basket 1 a.

The outer shape in a cross section perpendicular to the tube axis Zs (corresponding to the longitudinal direction in this example) of the spacer square pipe 20 is a rectangle, and the outer dimension on the long side (hereinafter referred to as the cross section long side) side in the cross section is l. ₃ , the outer dimension on the short side (hereinafter referred to as the short side of the cross section) of the cross section is l ₄ . The outer dimension l ₄ on the short side of the cross section corresponds to the distance between adjacent storage square pipes 3. If l ₄ is expressed by using the external dimension l _{2 in the} cross section perpendicular to the tube axis Zm of the support member 10 and the depth t ₁ of the corner outer side 10co of the support member 10, l ₄ = (l ₂ −2 × t ₁ ).

When the basket 1 a is assembled, the spacer square pipe 20 is disposed between the storage square pipes 3 adjacent to each other in the direction perpendicular to the outer surface 3 s of the storage square pipe 3. The outer side surface 20s ₁ on the long side of the cross section of the spacer square pipe 20 is in contact with the outer surface 3s of the storage square pipe and receives a force in a direction perpendicular to the outer surface 3s of the storage square pipe 3. At the same time, the heat released from the recycled fuel assembly stored in the storage square pipe 3 is transmitted to the outside of the basket 1a. In the basket 1a, sectional long side outer surface 20s ₁ spacer for square pipes 20, since the outer surface 3s of accommodating square pipe of abutting structure may take the contact area therebetween increases. Thereby, since the heat transfer area can be increased, sufficient heat transfer performance can be ensured when storing a recycled fuel assembly for PWR that generates a large amount of heat.

In addition, an outer surface on the short side of the cross section (hereinafter referred to as an outer surface on the short side of the cross section) 20s ₂ in a cross section perpendicular to the tube axis Zs of the spacer square pipe 20 faces the outer surface 10s of the support member 10. If the outer dimension l ₃ on the long side of the cross section of the square pipe for spacer 20 is (l ₁ −2 × t ₁ ), the short side outer surface 20s ₂ and the outer surface 10s of the support member 10 are in contact with each other. It becomes like this. Here, l ₁ is the length of one side of the storage square pipe 3, and t ₁ is the depth of the recess formed in the corner outer side 10 co of the support member 10. The contact area between the storage square pipe 3 and the spacer square pipe 20 can be increased as the outer dimension l ₃ on the long side of the cross section of the spacer square pipe 20 is increased. For this reason, if the heat transfer between the storage square pipe 3 and the spacer square pipe 20 is taken into consideration, it is preferable to increase the outer dimension l ₃ as much as possible.

  FIG. 5A is a perspective view illustrating the whole basket according to the first embodiment. As described above, the basket 1 a is configured by combining the storage square pipe 3, the support member 10, and the spacer square pipe 20. As a whole, for example, as shown in FIG. The recycled fuel assembly is stored in the storage square pipe 3 and stored in a storage pool in a nuclear facility, or stored in a cask or canister.

  FIG. 5-2 is a perspective view illustrating an outline of a cask that is an example of a recycled fuel assembly storage container. FIG. 5C is a plan view of the cask shown in FIG. As shown in FIG. 5B, the cask 200 includes a lid 200T and a trunk 200B, and after the recycled fuel assembly is accommodated in the trunk 200B, the cask 200 is sealed by the lid 200T. As shown in FIG. 5C, the trunk 200 </ b> B of the cask 200 includes a cylindrical trunk body 201, a heat transfer fin 207 attached to the outer periphery of the trunk body 201, and the other long side end of the heat transfer fin 207. And an outer cylinder 205 attached to the section. The trunk body 201 is made of carbon steel or stainless steel having a sufficient thickness in order to exhibit the function of shielding γ rays. In addition, when manufacturing the trunk | drum main body 201 with carbon steel, in order to exhibit sufficient gamma ray shielding function, the thickness of the trunk | drum main body 201 shall be 20-30 cm.

  The bottom plate can be attached to the barrel main body 201 by welding to the barrel main body 201. Also, by inserting a metal billet into a container having an internal shape that matches the outer shape of the trunk body 201, and hot expanding the metal billet with a perforated punch having an outer shape that matches the inner shape of the trunk body 201 You may shape | mold the trunk | drum main body 201 and a baseplate integrally. Furthermore, you may manufacture the trunk | drum main body 201 by casting.

  The interior of the trunk body 201 serves as a cavity 201c in which the basket 1a that stores the recycled fuel assembly is stored. The internal shape of the cross section perpendicular to the axial direction (direction indicated by Z in the figure) of the cavity 201c is circular, but has an internal shape of the cross section such as an octagon, a substantially cross shape, or a staircase shape according to the specifications of the cask 200. A cavity can also be used. Since the cavity 201c has a circular shape in the cross section, when the basket 1a having a polygonal outer shape is stored, the first basket support 202a and the second basket support 202b are connected to each other between the basket 1a and the cavity 201c. The basket 1a is positioned in the cavity 201c with a gap therebetween.

After the recycled fuel assembly is housed in the cavity 201c, the primary lid 200T ₁ and the secondary lid 200T ₂ (FIG. 5-2) are opened to the cylinder in order to prevent radioactive material from leaking from the cylinder body 201. Attached to the part 200Bo, the cavity 201c is double sealed. In order to ensure sealing performance, a metal gasket is provided between the primary lid 200T ₁ and the secondary lid 200T ₂ and the trunk body 201.

  A plurality of heat transfer fins 207 made of a plate-like member are radially attached to the outer periphery of the trunk body 201. The heat transfer fins 207 are made of a heat conductive material such as an aluminum plate or a copper plate, and are joined to the outer periphery of the trunk body 201 by welding or other joining means. An outer cylinder 205 made of carbon steel having a thickness of several centimeters is attached to the outside of the heat transfer fin 207 by welding or other joining means. The recycled fuel assembly housed in the cavity 201c generates decay heat. The decay heat is transmitted to the outer cylinder 205 through the heat transfer fins 207 after being transmitted through the basket 1 a and the trunk body 201, and is released into the atmosphere from the surface of the outer cylinder 205.

  A space 209 surrounded by the trunk body 201, the outer cylinder 205, and the two heat transfer fins 207 is filled with a material having a neutron shielding function in order to absorb neutrons. As a material having such a function, a polymer material containing a large amount of hydrogen, such as resin, polyurethane, silicon, or other neutron absorbing material can be used. With this neutron absorbing material, neutrons emitted from the recycled fuel assembly are shielded, and neutrons leaking to the outside of the cask 200 are reduced below the regulation value.

  The cask 200 is used for transporting and storing after storing the recycled fuel assembly. When transporting the cask, shock absorbers are attached to both ends in the axis Z direction of the cask so that sufficient sealing performance can be ensured even in the event of a fall accident of the cask 200 or the like.

(Modification 1)
Next, a basket according to a first modification of the first embodiment will be described. This basket has substantially the same configuration as that of the basket according to the first embodiment, except that the long-side end of the spacer square pipe is projected. Since other configurations are the same as those of the first embodiment, description thereof is omitted. FIG. 6A is a plan view of a part of the basket according to the first modification of the first embodiment. FIG. 6B is a plan view of the spacer square pipe according to the first modification of the first embodiment.

  In the spacer square pipe 21 used in the basket 1b, a rib 21r is disposed between two plate-like members 21p substantially perpendicularly to them. The rib 21r is disposed closer to the axis Zs than the end on the long side of the plate-like member 21p (corresponding to the end 21tt of the projecting portion 21t in this example). For this reason, the protruding portion 21t protrudes from the outside of the rib 21r. Thus, the spacer square pipe 21 has a shape in which the end portion on the long side is projected. A space surrounded by the two ribs 21r and the two plate-like members 21p is a through hole 21h that extends in the axis Zs direction (corresponding to the longitudinal direction in this example) of the spacer square pipe 21. This through hole 21h serves as a flux trap.

When the basket 1b is configured by combining the spacer square pipe 21, the storage square pipe 3, and the support member 10, the side surface 10s (FIG. 3-2) of the support member 10 and the end portion 21tt of the overhang portion 21t Face each other. And the space A (FIG. 6-1) enclosed by the two overhang | projection parts 21t and the side surface 10s of the supporting member 10 is formed. Since the space A forms a flux trap in the vicinity of the support member 10, the subcritical function can be further improved. Further, since the strength of the spacer square pipe 21 is improved by the rib 21r, the force in the direction parallel to the rib 21r can be more reliably received and the safety when the cask is dropped can be improved. Further, since the outer side surface 21s _{1 of the} long side of the spacer square pipe and the outer side surface 3s of the storage square pipe 3 are in contact with each other, the heat transfer performance of the basket 1b can also be improved.

  A rib may be further added in the through hole 21h in parallel with the rib 21r. If it does in this way, the intensity | strength of the square pipe 21 for spacers can further be improved. Further, the heat transfer area between the plate-like members 21p can be increased by increasing the number of ribs. Thereby, since the heat transfer efficiency of the whole basket 1b can be improved, it is suitable for storing a recycle fuel assembly for PWR having a high burnup.

(Modification 2)
Next, a basket according to a second modification of the first embodiment will be described. This basket has substantially the same configuration as the basket according to the first embodiment, but a rib is provided in the through hole of the spacer square pipe to connect the long side of the cross section in the cross section perpendicular to the axis of the spacer square pipe. Different points. Since other configurations are the same as those of the first embodiment, description thereof is omitted. FIG. 7-1 is a plan view illustrating a part of the basket according to the second modification of the first embodiment. FIG. 7B is a plan view of the spacer square pipe according to the second modification of the first embodiment. 7-3 is a plan view illustrating another spacer square pipe according to a second modification of the first embodiment. FIG.

As shown in FIG. 7A and FIG. 7B, with respect to the short side 22p ₂ in the cross section perpendicular to the tube axis Zs direction (here, corresponding to the longitudinal direction) of the spacer square pipe 22 used in the basket 1c. Ribs 22r are provided substantially in parallel. That is, the spacer square pipe 22 has a cross-section structure in which a rib 22r is provided inside a rectangular pipe having a rectangular cross section. Rib 22r is provided between the cross-sectional long side side plate member 22p ₁ two, are disposed substantially perpendicular to the plate-like member 22p. Thereby, since the rigidity of the square pipe 22 for spacers improves, the intensity | strength of the basket 1c whole can be improved. The through hole of the spacer square pipe 22 is partitioned by ribs 22r, the through-hole 22h ₁ and 22h _2. These serve as flux traps. The thickness t ₃ of the rib 22r may be the same as or different from the thickness t ₂ of the spacer square pipe 22. In this example, ribs 22r are positioned at a substantially central portion of the cross-sectional long side side plate member 22p ₁ spacer for square pipes 22. That is, the distance of the outer side surface of the cross-section short side in a cross section perpendicular to the tube axis Zs of the spacer square pipe 22 (hereinafter sectional short side outer surface) 22s ₂ to ribs 22r becomes l _3/2. Incidentally, the ribs 22r may be disposed in a portion other than the substantially central portion of the cross-sectional long side side plate member 22p _1.

When the basket 1c is configured by combining the spacer square pipe 22, the storage square pipe 3, and the support member 10, the side surface 10s (FIG. 3-2) of the support member 10 and the short cross section of the spacer square pipe are formed. The side outer surface 22s ₂ faces each other. In addition, since the outer side surface 22s ₁ on the long side of the cross section of the square pipe 22 for spacer and the outer side 3s of the storage square pipe 3 are in contact, the heat transfer performance of the basket 1b is improved. Furthermore, the heat transfer between the plate-like members 22p is improved by the ribs 22r.

In addition, it is good also as the character shape of the cross section which made the number of ribs 22r 'two like the square pipe 22' for spacers shown to FIGS. 7-3. The number of ribs is not limited to one or two, and may be three or more. When two or more ribs are arranged, the interval between the ribs 22r ′ and the interval between the short-side plate member 22p ₂ ′ and the rib 22r ′ may be equal or different.

(Modification 3)
Next, a basket according to a third modification of the first embodiment will be described. This basket has substantially the same configuration as the basket according to the first embodiment, except that the spacer square pipe and the support member are connected by a connecting structure. Since other configurations are the same as those of the first embodiment, description thereof is omitted. FIG. 8 is a plan view illustrating a part of a basket according to a third modification of the first embodiment. FIG. 9A is a plan view illustrating a support member according to a third modification of the first embodiment. FIG. 9-2 is an enlarged view illustrating a connecting portion of the support member according to the third modification of the first embodiment. FIG. 10A is a plan view of the spacer square pipe according to the third modification of the first embodiment. FIG. 10-2 is an enlarged view showing a connecting portion of the spacer square pipe according to the third modification of the first embodiment.

  The spacer square pipe 23 and the support member 13 constituting the basket 1d are structured to be connected to each other. As shown in FIG. 9A, four outer side surfaces 13 s of the support member 13 are provided with concave connection portions 13 j, respectively. As shown in FIG. 9-2, the connecting portion 13j includes a connecting portion inlet 13ji and a connecting portion inside 13jj. And the opening length hi of the connection part inlet_port | entrance 13ji is formed smaller than the internal length hj of the connection part inside 13jj. Further, the support member 13 is provided with a through hole 13h having a diameter d penetrating in the direction of the tube axis Zm. When the basket 1d is assembled, it functions as a flux trap.

As shown in FIG. 10A, a convex protrusion 23j is formed on the outer surface 23s ₂ on the short side of the cross section (hereinafter referred to as the short side outer surface) in the cross section perpendicular to the tube axis Zs of the spacer square pipe 23. Is provided. As shown in FIG. 10-2, the protruding portion 23j includes a shaft portion 23ji and a flange portion 23jj. The width ki of the shaft portion 23ji is formed smaller than the width kj of the flange portion 23jj. Further, since the flange portion 23jj is fitted into the connecting portion inside 13jj of the connecting portion 13j of the support member 13, the width kj of the flange portion 23jj is slightly smaller than the internal length hj of the connecting portion inside 13jj. Similarly, the width ki of the shaft portion 23ji is configured to be slightly smaller than the opening length hi of the connecting portion inlet 13ji.

  When the basket 1d is assembled, the protrusion 23j is fitted with the connecting portion 13j of the support member 13. Then, the flange portion 23jj of the protrusion 23j of the spacer square pipe 23 is engaged with the connection portion inlet 13ji provided in the connection portion 13j of the support member 13, so that the spacer square pipe 23 and the support member 13 are connected. Thereby, since the square pipe 23 for spacers and the support member 13 are couple | bonded firmly, the basket 1d whole becomes a firm structure. As a result, the durability of the basket 1d against the impact force when the cask is dropped is improved. Further, by connecting the spacer square pipe 23 and the support member 13, the contact portion between the two is increased, so that the heat transfer performance is also improved.

In the above example, the concave connecting portion is provided on the support member 13 and the convex protrusion is provided on the spacer square pipe 23 side. However, the concave connecting portion is provided on the spacer square pipe 23 side. Protrusions may be provided on the support member 13. Moreover, you may provide a concave connection part in the support member 13 and the square pipe 23 for spacers alternately. Further, a plurality of connecting portions may be formed on one of the outer surfaces 13 s ₁ of the support member 13. For example, one concave connecting portion and one convex protruding portion are formed on one of the outer surfaces 13s _1, a plurality of concave connecting portions are formed, or a plurality of convex protruding portions are formed. be able to.

  FIGS. 11A and 11B are plan views illustrating another connection structure according to the third modification of the first embodiment. As shown in FIG. 11A, the connecting structure of the spacer square pipe 23a and the support member 13a may be constituted by a dovetail groove 13aj and a protrusion 23aj fitted in the dovetail groove 13aj. Further, as shown in FIG. 11-2, the flange portion 23bjj constituting the connection portion 23bj of the spacer 23b is formed into a circular cross section, and the connection portion inside 13bjj constituting the connection portion 13bj of the support member 13b into which the flange portion 23b is fitted is It is good also as a shape matched with the cross-sectional shape of the part 23bjj.

  As mentioned above, according to Example 1 and its modification, the storage square pipe, the support member, and the spacer square pipe are combined to constitute the basket for storing the recycled fuel assembly. Thereby, since each structural member can be extrusion-molded with a small extrusion thrust, even if it is a case where a difficultly extruded material like a B-Al material is used, it can manufacture efficiently. In Example 1 and its modification, the support member and the spacer square pipe may be manufactured from an Al alloy having excellent thermal conductivity, or manufactured from a B-Al alloy having a neutron shielding function. Also good. Further, the support member and the spacer square pipe may be fixed by a joining means such as FSW (Friction Stirred Welding) or welding. Furthermore, the support member and the spacer square pipe may be coupled by screws or other fastening means. The portion where the support member and the spacer square pipe come into contact with the cavity of the cask may be fixed by screws or other fastening means.

  The recycled fuel assembly storage basket according to the second embodiment is arranged in a lattice shape, contacts a storage square pipe that stores the recycled fuel assembly therein, an outer surface of the storage square pipe, and And a spacer member arranged between the storage square pipes. In the second embodiment, the spacer member functions as a spacer of the storage square pipe.

FIG. 12-1 is an explanatory diagram of the recycled fuel assembly storage basket according to the second embodiment. FIG. 12-2 is an explanatory diagram of a combination of spacer members of the recycled fuel assembly storage basket according to the second embodiment. As shown in FIG. 12A, the basket 1e according to the second embodiment is configured by disposing spacer members 30 each having a plurality of protrusions on both surfaces of a flat plate between the storage square pipes 3 arranged in a lattice shape. Is done. The first end portion 30t ₁ of the first projection 30r ₁ formed in the spacer member 30, and a second second end 30t ₂ of projections 30r ₂ abuts against the outer side surface 3s of accommodating square pipe 3 .

FIG. 13A and FIG. 13B are explanatory views of the spacer member constituting the basket according to the second embodiment. As shown in FIG. 13A, the spacer member 30 has a first protrusion 30r ₁ and a second protrusion 30r ₂ formed on both surfaces of the flat plate 30p. In this example, four first protrusions 30r ₁ and second protrusions 30r ₂ are formed, but the number is not limited to this. 13-2, the space C ₁ surrounded by the two first protrusions 30r ₁ and the outer side surface 3s of the storage square pipe 3 and the two second protrusions 30r ₂ and the storage corners. A space C ₂ surrounded by the outer surface 3 s of the pipe 3 serves as a flux trap.

As shown in FIG. 13-2, the distance between the outer side surfaces 3s of the storage square pipe 3 is a, which corresponds to the distance between the first end 30t ₁ and the second end 30t ₂ of the spacer member 30. To do. Further, the length of the first protrusion 30r ₁ is different from the length of the second protrusion 30r ₂ . Specifically, the length of the first protrusion 30r ₁ is a / 2−t ₅ and the length of the second protrusion 30r ₂ is a / 2. Thereby, in the cross section perpendicular to the axis Zs of the spacer member 30, the flat plate 30 p is located at a location offset from the intermediate position between the outer surfaces 3 s of the storage square pipe 3. 12B, when the spacer members 30 are combined, the end portions 30pt of the flat plate 30p are combined so as to contact the end side surface 30ts of the other flat plate 30p. Thereby, when assembled as the basket 1e, the shift | offset | difference of the spacer member 30 can be suppressed.

  As mentioned above, since the spacer member which comprises the basket which concerns on Example 2 is a structure in which several protrusion is each formed in both surfaces of a flat plate, a core is unnecessary in the case of extrusion molding. For this reason, when using the B-Al material which is a hardly extrudable material, it can be molded with a relatively low extrusion pressure. As a result, the basket according to Example 2 can be manufactured relatively efficiently even when the B content is increased, and thus it is easy to ensure the subcritical function. Further, since the core is not necessary when the spacer member constituting the basket according to the second embodiment is extruded, it can be manufactured at a lower cost. In addition, the spacer member of the basket which concerns on Example 2 can also be manufactured by cutting. Furthermore, since the basket can be constituted by the storage square pipe and the spacer member, the types of members constituting the basket are reduced. Thereby, the manufacturing cost of a basket can further be reduced.

(Modification 1)
Next, a basket according to a first modification of the second embodiment will be described. This basket has substantially the same configuration as that of the basket according to the second embodiment, but is different in that the basket is configured by using two types of large and small spacer members. Since other configurations are the same as those of the first embodiment, description thereof is omitted. FIG. 14 is a plan view illustrating a part of a basket according to a first modification of the second embodiment. FIGS. 15A and 15B are plan views of the spacer member constituting the basket according to the first modification of the second embodiment.

In the basket 1f, a first spacer member 31 and a second spacer member 32 having a larger width are arranged between the storage square pipes 3 arranged in a lattice pattern. As shown in FIG. 14, the first outer side surface 31 s ₁ of the first spacer member 31 abuts on the outer side surface 3 s of the storage square pipe 3. The first spacer members 31 are arranged in a specific direction. For example, the first outer side surfaces 31s _{1 of} all the first spacer members 31 are arranged so as to be orthogonal to one specific direction (here, the X direction) of the basket 1f. The second spacer member 32 is orthogonal to the first outer surface 31 s ₁ of the first spacer member 31, that is, the flat plate portion 32 p of the second spacer member is orthogonal to the flat plate portion 31 p of the first spacer member 31. To be arranged.

The first spacer member 31 and the second spacer member 32 have a shape in a cross section perpendicular to the axis Zs, which is obtained by bending a single plate into a wave shape. As shown in FIG. 15A, the first spacer members 31 are arranged in parallel and alternately with the first flat plate portions 31p, and the first spacer members 31 are orthogonal to the first flat plate portions 31p and alternately arranged with the first flat plate portions 31p. And a first rib 31r that connects the flat plate portion 31p. In addition, a first open rib 31 r ′ is provided at the long side end of the spacer member 31. Then, the first outer surface 31s ₁ of the first flat plate portion 31p and the rib end portion 31rt ′ of the first opening rib 31r ′ are in contact with the outer surface 3s of the storage square pipe 3. Further, the second outer side surface 31s _{2 of} the first rib 31r abuts on and supports the second spacer member 32. The long side length l ₁ of the cross section in the cross section perpendicular to the axis Zs direction of the first spacer member 31 is equal to the length of one side of the storage square pipe 3, and the short side length a of the cross section is the basket 1f. It is equal to the distance between the outer side surfaces 3s of the storage square pipe 3 to constitute.

As shown in FIGS. 14 and 15-2, the cross-section long side length L ₃ in the cross section perpendicular to the axis Zs of the second spacer member 32 is the cross section in the cross section perpendicular to the axis Zs direction of the first spacer member 31. It is larger than the long side length l ₁ and larger than the length of one side of the storage square pipe 3. Accordingly, the plurality of storage square pipes 3 can be supported by the single second spacer member 32. The long side length L ₃ of the cross section of the second spacer member 32 can be determined as appropriate depending on manufacturing restrictions and the like, but is sufficient to support all the storage square pipes 3 arranged in one row of the basket 1f. It is preferable to use a length.

The second spacer members 32 are parallel to and alternately arranged second flat plate portions 32p and second ribs 32r that are orthogonal to the second flat plate portions 32p and connect the alternately arranged second flat plate portions 32p. It is comprised including. The first outer side surface 32s ₁ of the second flat plate portion 32p abuts on the outer side surface 3s of the storage square pipe 3 to support the storage square pipe 3. The short side length a of the cross section in the cross section perpendicular to the axis Zs direction of the second spacer member 32 is equal to the distance between the outer side surfaces 3s of the storage square pipe 3 of the basket 1f.

  As mentioned above, since the spacer member which comprises the basket which concerns on the 1st modification of Example 2 is the structure which bent the sheet | seat of 1 sheet in the shape of a wave, a core is unnecessary in the case of extrusion molding. For this reason, when using the B-Al material which is a hardly extrudable material, it can be molded with a relatively low extrusion pressure. As a result, the basket according to Example 2 can be manufactured relatively efficiently even when the B content is increased, and thus it is easy to ensure the subcritical function. Further, since this basket has a structure in which a large number of ribs are arranged in a direction perpendicular to the outer surface of the storage square pipe, the entire basket can be made to have a strong structure. Moreover, since a core is unnecessary when the spacer member which comprises the basket which concerns on the 1st modification of Example 2 is extrusion-molded, it can manufacture by that much inexpensively. In addition, the spacer member of the basket which concerns on Example 2 can also be manufactured by cutting.

(Modification 2)
Next, a basket according to a second modification of the second embodiment will be described. This basket has substantially the same configuration as that of the basket according to the second embodiment, but a plate-like spacer member having long side ends formed in a step shape is disposed between storage square pipes arranged in a lattice shape. And the point which comprises the long side edge part of the said spacer member combining is different. Since other configurations are the same as those of the first embodiment, description thereof is omitted.

  FIG. 16A is a plan view illustrating a part of a basket according to a second modification of the second embodiment. FIG. 16-2 is a plan view of the spacer constituting the basket according to the second modification of the second embodiment. As shown in FIG. 16A, the basket 1 g is configured by combining the storage square pipes 3 arranged in a lattice shape and a plate-like spacer member 33.

The spacer member 33 is a hollow plate having a through hole extending in the axis Zs direction and is partitioned by ribs 33r extending in the axis Zs direction. The two through holes 33h ₁ and 33h ₂ partitioned by the rib 33r serve as a flux trap. The length of the spacer member 33 in the axis Zs direction is substantially equal to the length L ₁ (see FIG. 2-1) of the storage square pipe 3 in the tube axis Zp direction. When the spacer member 33 is viewed from the direction orthogonal to the first outer side surface 33s ₁ , the projected image of the spacer member 33 is rectangular. In this case, the end on the long side of the spacer member 33 is referred to as a long side end (33s _{2 in} FIG. 16-2).

As shown in FIG. 16B, the long side end portion 33s ₂ of the spacer member 33 is formed in a step shape by providing a projection 33t having a square cross section. The shape of the cross section perpendicular to the axis Zs of the spacer member 33 is point-symmetric with respect to the axis Zs. In the cross section perpendicular to the axis Zs of the spacer member 33, the short side length of the cross section is a. Moreover, the cross-sectional shape of the protrusion 33t is a square having a side length of a / 2.

When assembling the basket 1g is long side end portion 33s ₂ between the spacer member 33 are combined (the portion indicated by D in FIG. 16-1). At this time, the first end surface 33St ₁ long side end 33s _2, a second end surface 33St ₂ other long side edge portion 33s ₂ abuts. At the same time, the third end surface 33St ₃ on the long side end 33s _2, and the fourth end surface 33St ₄ other long side edge portion 33s ₂ abuts. The first outer surface 33s ₁ of the spacer member 33 abuts the outer surface 3s of accommodating square pipe 3.

As described above, in the second modified example of the second embodiment, the plurality of spacer members 33 are combined at the long side end portion 33s ₂ with the above configuration, so that the spacer members 33 can be accurately positioned. Further, the contact area of the long side end portion 33s ₂ of spacer member 33 is increased, can be transmitted to the impact force when the cask falls efficiently. Thereby, the basket 1g is comprised firmly. Furthermore, since the heat transfer area between the storage square pipe 3 and the spacer member 33 can be increased and the heat transfer area between the spacer members 33 can be increased, the heat transfer performance of the basket 1g as a whole is also improved. In addition, since the spacer member 33 has a relatively small size, when the B-Al material which is a hardly extrudable material is used, the spacer member 33 can be formed with a relatively small extrusion pressure. Thereby, the basket which concerns on the 2nd modification of Example 2 can be manufactured comparatively efficiently even when the B-Al material which is a difficult-to-extend material is used.

  In Example 2 and modifications thereof, the spacer member may be manufactured from an Al alloy having excellent thermal conductivity, or may be manufactured from a B—Al alloy having a neutron shielding function. Further, the spacer members may be fixed by a joining means such as FSW (Friction Stirred Welding) or welding. Further, the spacer members may be coupled by screws or other fastening means. Further, the portion where the spacer member contacts the cavity of the cask may be fixed by a screw or other fastening means.

  In the basket according to the third embodiment, a cross member whose cross section perpendicular to the axial direction is formed by combining cross-shaped cross members at the long side ends thereof to form a lattice-shaped space, and a storage square pipe is provided in the space. There is a feature in the point to arrange. In the following description, the description of the same configuration as in the first and second embodiments is omitted. In Example 3, the cross member functions as a spacer for the storage square pipe.

FIG. 17A is a plan view of a part of the basket according to the third embodiment. FIG. 17-2 is a plan view of the cross member constituting the basket according to the third embodiment. The basket 1 h according to the third embodiment is configured by combining a cross member 40 having a cross-shaped cross section and a storage square pipe 3. As shown in FIG. 17-2, the cross member 40 has a substantially cross-shaped shape in a cross section perpendicular to the tube axis Zm direction (corresponding to the longitudinal direction here), and the four arms 40a have a cross-shaped central portion 40c. Cross at. Protruding length of the arm 40a is l _6/2, set slightly larger than half of the one side outside the length l ₁ accommodating square pipes 3. The thickness of the arm 40a is a, which corresponds to the distance between the outer side surfaces 3s of the adjacent storage square pipes 3 when the basket 1h is assembled.

First through hole 40h ₁ diameter d towards the tube axis Zm direction is provided in the central portion 40c. Each arm 40a is also provided with a second through-hole 40h ₂ extending in the tube axis Zm direction. When the basket 1 h is assembled, the first through hole 40 h ₁ functions as a flux trap that shields neutrons emitted in the direction of the corners of the storage square pipe 3. Note that the first through-hole 40h _1, may be placed neutron absorbing material as needed. The second through hole 40h ₂ functions as a flux trap that shields neutrons emitted in the direction perpendicular to the outer surface 3s of the storage square pipe 3.

  When the basket 1h is assembled, the cross members 40 are combined with the long-side end portions 40t (open ends of the arms 40a) being butted together. At this time, a space surrounded by the outer side surfaces 40s of the four cross members 40 is formed. This space has a substantially square cross-sectional shape perpendicular to the tube axis Zm, and the storage square pipe 3 is disposed here.

  As described above, in the basket according to the third embodiment, the storage square pipe is arranged in a space formed by combining cross members having a cross-shaped cross section. Thereby, the contact area of a cross member and a storage square pipe can be enlarged, and the heat transfer performance of the whole basket can be improved. In addition, since the dimensions of the cross member are relatively small, even a difficult-to-extrusion material such as a B-Al material has a relatively low extrusion pressure and relatively little wear on the extrusion die, so that it can be manufactured relatively efficiently. it can.

(Modification 1)
Next, a basket according to a first modification of the third embodiment will be described. This basket has substantially the same configuration as the basket according to the third embodiment, but includes a cross member provided with an arm having a convex portion formed at the end on the long side and an arm formed with a recess at the end on the long side. The long side edge part in which the convex part was formed and the long side edge part in which the recessed part was formed differ. Since other configurations are the same as those of the third embodiment, description thereof is omitted.

FIG. 18 is a plan view illustrating a part of a basket according to a first modification of the third embodiment. The first arm 41a ₁ provided in the cross member 41 constituting the basket 1i has a convex portion having a substantially triangular cross section at the first long side end portion 41t ₁ . Further, the second arm 41a ₂ provided in the cross member 41 has a concave portion having a substantially triangular cross section at the second long side end portion 41t ₂ . When the basket 1i is assembled, the first long side end 41t ₁ and the second long side end 41t ₂ of the cross member 41 are brought into contact with each other, and a plurality of cross members 41 are combined.

As described above, since the concave portion and the convex portion formed at the end portion on the long side are combined, the positioning accuracy of the cross member 41 can be improved and the displacement of the cross members 41 can be suppressed. It becomes easy. Further, since the concave portion and the convex portion having a substantially triangular cross section are combined, the contact area between the first long side end 41t ₁ and the second long side end 41t ₂ is increased. Thereby, since heat conduction between the cross members 41 is improved, the heat transfer performance of the entire basket 1i is also improved.

Further, the impact force at the time of cask fall is transmitted from the long side end of the cross member 41 adjacent the contact of the first lateral side edge by the structure 41 t ₁ and the second lateral side edge 41 t ₂ Since the area is increased, the impact stress generated on the contact surface between the long side end portions can be reduced. Thereby, durability as the basket 1i whole can be improved. Further, since the concave portion and the convex portion having a substantially triangular cross section are combined, if the cross member 41 is made of a material having a neutron absorbing ability such as a B-Al material, it passes through the butted portion at the end portion on the long side. Neutrons can also be suppressed.

(Modification 2)
Next, a basket according to a second modification of the third embodiment will be described. This basket has substantially the same configuration as that of the basket according to the third embodiment, except that it includes an arm having long side end portions formed in a step shape, and the long side end portions are combined with each other. Since other configurations are the same as those of the third embodiment, description thereof is omitted.

FIG. 19 is a plan view illustrating a part of a basket according to a second modification of the third embodiment. The first arm 42a ₁ provided in the cross member 42 constituting the basket 1j has a first long-side end portion 42t ₁ formed in a step shape in a cross section perpendicular to the tube axis Zm direction. Further, the second arm 42a ₂ provided in the cross member 42 has a second long side end portion 42t ₂ formed in a step shape in a cross section perpendicular to the tube axis Zm direction. As shown in the lower left cross member 42 in FIG. 19, in the cross section perpendicular to the tube axis Zm of the cross member 42, the first arm 42a ₁ is arranged symmetrically with respect to the tube axis Zm, and the second arm 42a _{2 is} also arranged point-symmetrically with respect to the tube axis Zm. When assembling the basket 1j, the second long side end 42t ₁ and the second long side end 42t ₂ of the cross member 42 are brought into contact with each other, and a plurality of cross members 42 are combined.

As described above, since the long side end portions formed in a staircase shape are combined with each other, the positioning accuracy of the cross member 42 is improved and the displacement of the cross members 42 can be suppressed, so that the assembly of the basket 1j is facilitated. . In addition, since the long-side end portions formed in a step shape are combined, the contact area between the first long-side end portion 42t ₁ and the second long-side end portion 42t ₂ is increased. Thereby, since the heat conduction between the cross members 42 is improved, the heat transfer performance of the entire basket 1i is also improved.

Further, the impact force when the cask is dropped is transmitted from the long side end of the adjacent cross member 42, but the contact between the first long side end 42t ₁ and the second long side end 42t ₂ by the above configuration. Since the area is increased, the impact stress generated on the contact surface between the long side end portions can be reduced. Thereby, durability as the whole basket 1j can be improved. Furthermore, since the long side end portions formed in a staircase shape are combined, if the cross member 42 is made of a material having a neutron absorbing ability such as a B-Al material, it passes through the butted portion at the long side end portion. It is also possible to suppress neutrons.

  In Example 3 and its modifications, the cross member may be manufactured from an Al alloy having excellent thermal conductivity, or may be manufactured from a B—Al alloy having a neutron shielding function. Further, the cross members may be fixed by a joining means such as FSW (Friction Stirred Welding) or welding. Further, the cross members may be coupled by screws or other fastening means. Further, the portion where the spacer member contacts the cavity of the cask may be fixed by a screw or other fastening means.

  In the basket according to the fourth embodiment, the square pipe-shaped members are stacked perpendicularly to each other and inclined with respect to the bottom surface of the basket so that the long side end portions are in contact with each other, and are surrounded by the square pipe-shaped members. It is characterized in that a square pipe for storage is arranged in a shaped space. In Example 4, the square pipe-shaped member functions as a spacer for the storage square pipe.

  FIG. 20A is a plan view of the basket according to the fourth embodiment. 20-2 is a side view seen from the direction of arrow A in FIG. 20-1. 20-3 is a side view seen from the direction of arrow B in FIG. 20-1. FIG. 21A is an explanatory diagram of a first square pipe-shaped member that constitutes the basket according to the fourth embodiment. FIG. 21-2 is an explanatory diagram of a second square pipe-shaped member that constitutes the basket according to the fourth embodiment. FIG. 21C is an explanatory diagram of a wedge-shaped spacer that constitutes the basket according to the fourth embodiment.

As shown in FIGS. 20-1 to 20-3, the basket 1l has long side end portions 53t ₁ , 54t so that the first square pipe member 53 and the second square pipe member 54 are orthogonal to each other. ₁ are brought into contact with each other and stacked in the tube axis Zp direction of the storage square pipe 3. At this time, as shown in FIG. 20B, the first square pipe-shaped member 53 is disposed such that the tube axis Zs is inclined by the inclination angle θ with respect to the bottom 201b of the basket 11. For this reason, as shown to FIGS. 21-1, when the 1st square pipe-shaped member 53 is seen from a side surface direction, the 1st square pipe-shaped member 53 becomes parallelogram shape.

Further, the second square pipe-shaped member 54 combined with the first square pipe-shaped member 53 has an outer cross-sectional shape perpendicular to the axis Zs inclined with respect to the bottom 201b of the basket 11 so that the inclination angle θ can be maintained. The parallelogram is inclined by an angle θ (see FIG. 21-2). In order to maintain this inclination angle θ, a wedge-shaped spacer 55 is provided between the bottom 201b of the basket 11 and the long side end 53t _{1 of} the first square pipe-shaped member 53 as shown in FIG. Is placed. The storage square pipe 3 is arranged in a lattice-like space surrounded by the first square pipe-like member 53 and the second square pipe-like member 54 thus combined.

  With the above configuration, the first square pipe-shaped member 53 is inclined with respect to the bottom 201b of the basket 11 so that the water in the basket 11 can be easily drained. Moreover, since it is not necessary to form a drain hole in the 1st square pipe-shaped member 53 and the 2nd square pipe-shaped member 54, the manufacturing process of a double square pipe-shaped member can be simplified. In addition, by making the cross-sectional shape perpendicular | vertical to the axial direction of the 1st square pipe-shaped member 53 into a parallelogram shape, the 2nd square pipe-shaped member 54 is also inclined and arrange | positioned with respect to the bottom part 201b of the basket 1l. Also good. If it does in this way, the water of basket 1l can be drained more easily.

  Further, since air from the first rectangular pipe-shaped member 53 and the second rectangular pipe-shaped member 54 is easily removed, the air remaining in the first and second rectangular pipe-shaped members 53 and 54 can be reduced. Thereby, it becomes easy to ensure subcriticality, and the distance of the flux trap and the thickness of the neutron absorption layer can be set to the minimum. As a result, a compact and lightweight basket 11 can be obtained. Moreover, if the mass is the same as that of the conventional basket, a safer basket 11 can be configured.

(Modification)
In the basket according to the modification of the fourth embodiment, the plate-like members are combined so as to be orthogonal to each other and stacked in a plurality of stages, and the plate-like member is inclined with respect to the bottom surface of the basket, and the long-side end of the plate-like member It is characterized in that it is configured by combining notch portions provided between the portions.

  FIG. 22-1 is a perspective view illustrating a basket according to a modification of the fourth embodiment. FIG. 22-2 is a perspective view of a basket according to another modification of the fourth embodiment. The basket 300 shown in FIG. 22A is configured by combining a plate member 310 having a through hole 311 penetrating in the longitudinal direction and being laminated by a plurality of stages while being partitioned by a rib 313. A plurality of cutout portions 312 are formed at the long side end portion 310lt of the plate member 310, and the cutout portions 312 are combined with each other by making the plate members 310 orthogonal to each other.

  When assembling the basket 300, first, the plate-like members 310 constituting the first stage are arranged in parallel. Then, the plate-like member 310 constituting the second stage is made orthogonal to the plate-like member 310 constituting the first stage, and the notch portions 312 of the plate-like member 310 of the first stage and the second stage are combined. . This is sequentially repeated, and the plate-like member 310 is laminated to a required height, whereby the basket 300 is completed. The basket 300 includes a lattice-shaped space surrounded by a plurality of plate-like members 310. This space is called a cell, and the recycled fuel assembly is stored in this cell.

  The basket 301 shown in FIG. 22-2 is substantially the same as the basket 300 shown in FIG. 22-1, but the long-side end 310lt of the plate-like member 310a constituting the basket 301 has a protrusion 315 and The difference is that a recess 316 is formed. When the basket 301 is assembled, the convex portion 315 and the concave portion 316 of the plate-like member 310a that are stacked with the long side end portions 310lt aligned in the same direction are combined. By combining the convex portion 315 and the concave portion 316, the number of neutrons passing through the contact surfaces of the long side end portions 310lt of the plate-like member 310a can be reduced. Since the difference between the basket 300 and the basket 301 is only the point described above, the basket 300 is taken as an example in the following description.

  FIG. 22C is a side view of the plate-like member that constitutes the basket according to the modification of the fourth embodiment. FIG. 22-4 is a side view illustrating the notch portion of the plate-like member that constitutes the basket according to the modification of the fourth embodiment. FIG. 22-5 is a side view of the basket according to the modification of the fourth embodiment. As shown in FIG. 22C, the rib 313 provided inside the plate-like member 310 is inclined with respect to the bottom 201 b of the basket 300 by an angle θ. Further, as shown in FIG. 22-4, the cut direction of the notch 312 formed in the long side end 310lt of the plate-like member 310 is (90 ° −θ) with respect to the long side end 310lt. ) Just tilted. That is, the side surface 312s of the cutout portion 312 is inclined by (90 ° −θ) with respect to the long side end portion 310lt. Further, the bottom surface 312b of the cutout portion 312 is inclined by θ with respect to the bottom portion 201b of the basket 300, similarly to the long side end portion 310lt.

  When the basket 300 is assembled using the plate-like member 310 having such a notch 312, as shown in FIG. 22-5, the long-side end 310 lt and the rib 313 of the plate-like member 310 are formed on the basket 300. It is comprised so that it may incline with respect to the bottom part 201b. Thereby, the water in the plate-shaped member 310 can be easily drained. Further, since air in the plate-like member 310 is easily removed, the air remaining in the plate-like member 310 can be reduced. Thereby, it becomes easy to ensure subcriticality, and the distance of the flux trap and the thickness of the neutron absorption layer can be set to the minimum. As a result, a compact and lightweight basket 300 can be obtained. Moreover, if it is the same mass as the conventional basket, the safer basket 300 can be comprised.

  When the structure of the basket 300 according to the modified example of the reduction example 4 is not adopted, it is necessary to drill water drain holes in the plate member. When drilling a drain hole in a plate-shaped member, it is necessary to drill a long distance with respect to the hole diameter, and it is difficult to maintain the position of the hole, and the wear of the tool becomes severe. In addition, a large number of drain holes are required, and the number of plate-like members that perforate the drain holes is also large. Therefore, it is necessary to avoid providing drain holes in the plate-like member as much as possible. If the structure of the basket 300 which concerns on the modification of Example 4 is employ | adopted, since it is not necessary to provide a drain hole in the plate-shaped member 310, the said problem can be eliminated and the plate-shaped member 310 can be manufactured easily.

  22-6 is a cross-sectional view illustrating another configuration example of the plate-shaped member included in the basket according to the modification example of Example 4. FIG. The plate-like member 310 ′ shown in FIG. 22-6 has a parallelogram shape in cross section perpendicular to the longitudinal direction. The through hole 311 also has a parallelogram shape in cross section perpendicular to the longitudinal direction. The long side end portion 310lt ′ and the rib 313 ′ of the plate-like member 310 ′ are inclined with respect to the bottom portion 201b of the basket. With such a configuration, water and air can easily flow through the through hole 311, so that the water and air in the plate-like member 310 ′ can be discharged more easily.

  In the basket according to the fifth embodiment, the rectangular pipe-shaped members are stacked with the long-side end portions in contact with each other so as to be orthogonal to each other, and the storage square pipes are placed in a lattice-shaped space surrounded by the rectangular pipe-shaped members. Further, there is a feature in that a drainage passage is formed at the long side end of the square pipe member. In Example 5, the square pipe-shaped member functions as a spacer of the storage square pipe.

FIG. 23A is a perspective view of a part of the basket according to the fifth embodiment. FIG. 23-2 is a plan view of a part of the basket according to the fifth embodiment. FIG. 23-3 is an explanatory diagram illustrating a square spacer that constitutes the basket according to the fifth embodiment. Figure 23-1, as shown in Figure 23-2, the basket 1k is the long side end 50s ₂ is brought into contact so that the square pipe member 50 perpendicular to each other, the tube axis of the housing for square pipe 3 Stacked in the Zp direction. The storage square pipe 3 is disposed in a lattice-like space surrounded by the square pipe-like members 50. When the basket 1 k is assembled, a part of the side surface 50 s ₁ of the square pipe-shaped member 50 comes into contact with the outer side surface 3 s of the storage square pipe 3.

A long-side end portion 50s ₂ of square pipe-like member 50, the long side edge portion 50s ₂ and abutting portions of other square pipe-like member 50, the through hole 50h ₁ are formed. The square pipe member 50 is fixed to the through hole 50h ₁ by, for example, penetrating a bolt. In addition, the long side edge portion 50s ₂ of square pipe-like member 50, the water drain passage 50w are formed, during drainage in basket 1k discharges the water in the basket 1k through the drainage passage. At the same time, the water in the square pipe-like member is discharged from the opening 50h at the short side end.

  Due to the drainage passage 50w, it is not necessary to provide a drainage hole in the square pipe member 50. In the case where a drain hole is separately provided, processing for that is necessary. However, since the square pipe-like member 50 can integrally form the drain passage 50w by extrusion molding, the labor of such processing can be omitted. Moreover, since this square pipe-shaped member 50 has a simple structure, the extrusion pressure is relatively small even when a B-Al material, which is a hardly extrudable material, is used. For this reason, even if the content of B is increased, extrusion can be performed relatively efficiently, so that the subcritical function can be easily secured.

  FIGS. 24-1 and 24-2 are explanatory views showing other square pipe members applicable to the basket of the fifth embodiment. The square pipe-like member 51 shown in FIG. 24-1 has a substantially cross-shaped structure in which two ribs 51r are arranged perpendicularly to the flat plate 51p between two flat plates 51p. A portion surrounded by the rib 51r and the two flat plates 51p protruding from the rib 51r toward the long-side end 51t is a drainage passage 51w. Even with such a configuration, the drain hole of the square pipe-shaped member can be made unnecessary. Moreover, since the cross-sectional area of the water drainage passage 51w in the cross section perpendicular to the longitudinal direction of the square pipe member 51 can be increased, the water in the basket 1k can be discharged quickly and reliably. Furthermore, since the strength of the square pipe member 51 is improved by the two ribs 51r, the strength of the entire basket 1k is also improved.

  A square pipe-like member 52 shown in FIG. 24-2 chamfers a corner of a rectangular pipe having a rectangular cross section, and is provided with a chamfer 52c. The chamfered portion 52c serves as a water drainage passage so that water in the basket 1k can escape. Even with such a configuration, the drain hole of the square pipe-shaped member can be made unnecessary. In addition, these square pipe-shaped members 51 and 52 can be manufactured by extrusion molding.

  As mentioned above, in the basket of Example 5, since the drainage passage was provided in the long-side end part of the square pipe-shaped member, the water in a basket can be discharged | emitted efficiently. Moreover, since it is not necessary to provide a drain hole in the square pipe member by this drain passage, the manufacturing process of the square pipe member can be simplified. In addition, although the effect of efficiently draining the water in the basket can be obtained even with the structure of the basket according to the fifth embodiment alone, if the structure of the basket according to the fifth embodiment is applied to the structure of the basket according to the fourth embodiment, the water is further increased. The discharge efficiency can be improved.

  In Examples 4 and 5, the square pipe-shaped member may be manufactured from an Al alloy having excellent thermal conductivity, or may be manufactured from a B—Al alloy having a neutron shielding function. Further, the square pipe-shaped members may be fixed by a joining means such as FSW (Friction Stirred Welding) or welding. Further, the square pipe-shaped members may be coupled by screws or other fastening means. Further, the portion where the square pipe-shaped member contacts the cavity of the cask may be fixed by a screw or other fastening means.

  The basket according to the sixth embodiment has substantially the same configuration as that of the third embodiment, except that a spacer having a substantially L-shaped cross section and a storage square pipe are combined and the combination of the two is arranged in a lattice pattern. Other configurations are the same as those of the third embodiment. In Example 6, the spacer having a substantially L-shaped cross section functions as a spacer for a storage square pipe.

  FIG. 25 is a plan view illustrating a part of the basket according to the sixth embodiment. This basket 1m is configured by combining a storage square pipe 3 for storing a recycled fuel assembly and a spacer 60 having a substantially L-shaped cross section, and arranging the combination of both in a lattice pattern. The spacer 60 includes a plurality of protrusions 60t on the inner surface, and the outer surface 3s of the storage square pipe 3 and the protrusions 60t come into contact with each other. In addition, a recess is formed inside the corner portion of the spacer 60 in the longitudinal direction of the spacer 60 (in the tube axis Zp direction of the storage corner pipe 3), and is combined with the outer corner portion of the storage corner pipe 3 to be combined. (Part indicated by F in FIG. 25). As a result, the storage square pipe 3 and the spacer 60 are positioned.

The outer measurement surface 60s ₁ of the spacer 60 abuts on the outer surface 3s of the storage square pipe 3 disposed adjacently and the end surface 60s _{2 of the} spacer 60 disposed adjacently. Further, a through hole 60f extending in the longitudinal direction of the spacer 60 is formed inside the corner of the spacer 60, and this functions as a flux trap. A neutron shielding material may be inserted into the through hole 60f.

FIG. 26 is a plan view illustrating a basket according to a first modification of the sixth embodiment. Of the projections provided on the inner surface of the spacer 61 constituting the basket 1n, the projections 61t ₂ ends, the flared portion 61t ₃ is provided. Then, the flared portion 61t ₃ abuts the outer surface 3s of accommodating square pipe 3. Further, a protruding portion 61t ₁ of the outer side surface 3s Toko of accommodating square pipe 3 abuts. Thereby, the storage square pipe 3 and the spacer 61 are positioned.

Corners outside 61co of the spacer 61 is formed in a concave shape, when assembled basket 1n is said flared portion 61t ₃ and the corner portion outward 61co abuts. Thereby, the positioning of the adjacent spacers 61 can be facilitated. Further, two of the flared portion 61t _3, a space surrounded by the corner portions outside 61co is flux trap. A neutron shielding material may be inserted into this space.

FIG. 27 is a plan view illustrating a basket according to a second modification of the sixth embodiment. Basket 1o according to the second modification is substantially the same structure as the basket 1n according to a first modification of the embodiment 6, the corner outside 62co of the spacer 62 constituting the basket 1o, is fitted extending portion 62t ₃ The difference is that a step 62d is provided. When assembling the basket 1o, overhang 62t ₃ provided in the projections 62t ₂ of the end of the spacer 62, so fitted to the stepped portion 62d, the spacer 62 positioned between it is facilitated. Further, the basket 1o can be easily assembled.

FIG. 28 is a plan view illustrating a basket according to a third modification of the sixth embodiment. The basket 1p according to the third modified example has substantially the same configuration as the basket 1m according to the sixth embodiment, but differs from this in the following points. That is, the step portion 63d is provided on the corner outer side 63co of the spacer 63 constituting the basket 1p. When the end projection 63t ₂ of the spacer 63 is extended beyond the width of the storage square pipe 3 and the basket 1p is assembled, the end projection 63t ₂ and the stepped portion 63d are fitted together. With this arrangement, when assembling the basket 1p, since the end projections 63t ₂ of the spacer 63 and the stepped portion 62d is fitted, positioned between the spacer 63 is facilitated. In addition, the basket 1p can be easily assembled.

  FIGS. 29A to 29C are plan views illustrating a basket according to a fourth modification of the sixth embodiment. The basket 1q has a staggered arrangement of the first cells 66a formed by the storage square pipe 3 and the first element 64 having an L-shaped cross section, and a space surrounded by the first element 64 and the second element 65. The difference is that the recycled fuel assembly is stored inside the storage square pipe 3.

  As shown in FIG. 29-2, the first cell 66 a is formed by combining the outer surface 3 s of the storage square pipe 3 and the first element 64. Also, as shown in FIG. 29C, the second cell 66b is made up of two first elements 64 and one second element 65. As can be seen from FIG. 29-1, the first cells 66a are arranged in a staggered manner, and the second cells 66b are arranged next to the first cells 66a. That is, the second cells 66b are also arranged in a staggered manner.

Here, the first element 64 has an L-shaped cross section perpendicular to the longitudinal direction, and the first element 64 has a longitudinal direction on the inner side surface (the side where the storage square pipe 3 is disposed in the first element 64). A protrusion 64t directed in the direction is provided. Further, on the outer side of the corner portion of the first element 64, the first step portion 64d ₁ into which the end protrusion 65t ₂ of the second element 65 fits, and the second step portion 64d _{2 in which} the outer side of the corner portion of the storage corner pipe 3 fits. And are formed. On the other hand, the second element 65 also has an L-shaped cross section perpendicular to the longitudinal direction, but the second element 65 has a longitudinal shape on the outer side surface (the side where the storage square pipe 3 is disposed in the second element 65). A first protrusion 65t ₁ is provided in the direction. The first element 64 and the second element 65 are both made of a B—Al material in order to have a function of shielding neutrons.

When assembling the basket 1q, the first step portion 64d _1, which is formed at the corner portions outside of the first element 64, the end projection 65 t ₂ of the second element 65 is fitted. At the same time, the outer corner portion of the storage corner pipe 3 is fitted into the second step portion 64d ₂ formed outside the corner portion of the first element 64. Accordingly, the movement of the first and second elements 64 and 65 is restricted, and the movement of the first element 64 and the storage square pipe 3 is restricted. As a result, the assembly of the basket 1q becomes easy and the structure of the basket 1q becomes stronger.

The recycled fuel assembly is stored in the storage square pipe 3 constituting the first cell 66a and in the second cell 66b, that is, in a space surrounded by the two first elements 64 and one second element 65. Is done. In this space, the cross-sectional shape perpendicular to the longitudinal direction matches the outer shape of the recycled fuel assembly. The space surrounded by the projection 64t provided on the inner surface of the first element 64 and the storage square pipe 3, and the first projection 65t ₁ and end projection 65t _{2 of} the second element 65, and the storage square pipe 3 The space surrounded by the circle forms a flux trap. This flux trap shields neutrons emitted from the recycled fuel assemblies housed in the cells 66a and 66b.

  The basket 1q for storing the recycled fuel assembly stores the recycled fuel assembly in the storage square pipe 3 and a space surrounded by the two first elements 64 and the second element 65. For this reason, the number of storage square pipes 3 to be used can be halved. Further, in the basket 1q, the storage square pipes 3 are arranged in a staggered manner, so that the storage square pipes 3 are arranged every other piece in the direction perpendicular to the outer side surface 3s. Therefore, the number of storage square pipes 3 can be reduced. Thereby, the dimension in the direction orthogonal to the longitudinal direction of the basket 1q can be reduced. As a result, the external dimensions of the recycled fuel assembly storage container for storing the basket 1q can be made smaller than before. This means that the outer diameter of the shock absorber attached to a spent fuel storage container such as a cask can be kept small. Therefore, the weight of the cask can be reduced, and if the outer shape of the buffer body is the same, the crushing allowance of the buffer body can be increased, so that safety can be increased. Further, if the crushing amount of the buffer body is the same, the size of the buffer body can be reduced, so that it becomes easy to cope with the size limitation when the cask is transported on land. Further, if the outer dimensions of the spent fuel storage container remain the same, the number of recyclable fuel assemblies that can be stored can be increased.

  As described above, in the basket according to the sixth embodiment and the modified example thereof, the square pipe that stores the recycled fuel assembly and the spacer having the L-shaped cross section provided with the protruding portion on the inner surface are combined, and the combination of both is formed in a lattice shape. It is arranged and arranged. For this reason, since the surface areas of the square pipe and the spacer do not increase unnecessarily, they can be sufficiently manufactured even if the thrust of the extruder is not so large. Further, since the shape of the spacer is not so complicated, the life of the extrusion die can be secured. As a result, the recycled fuel assembly storage basket for PWR can be efficiently manufactured, and the manufacturing cost can be kept low. In particular, the effect of the present invention is remarkable when the recycled fuel assembly storage basket is formed of a hard-to-extrusion material such as an Al material containing B or a B compound.

(Manufacturing method for storage square pipe, etc.)
Here, a method for manufacturing the storage square pipe 3 will be briefly described. Note that the same manufacturing method can be applied to the case where the B-Al material is used as the component member of the basket, such as the spacer square pipe 20 and the support member 10. FIG. 30 is a flowchart showing a method for manufacturing a storage square pipe according to the present invention. First, Al or an Al alloy powder is prepared by a rapid solidification method such as an atomizing method (Step S201), and a powder of B or B compound is prepared (Step S202). In addition, the order with S202 of step S201 is not ask | required. These two particles are mixed by MA (Mechanical Alloying) described below (step S203). Mixing may be performed in an argon atmosphere. The reason why B or B compound is added to Al or Al alloy is that the basket 1a or the like needs to have a function of preventing the inserted recycled fuel assembly from reaching criticality.

Here, natural boron includes B ¹⁰ that contributes to neutron absorption and B ¹¹ that does not contribute to neutron absorption. Therefore, the use of concentrated boron enriched for B ¹⁰ having neutron absorbing capability, ability to absorb neutrons natural boron if the addition amount of the same boron only as it becomes often to B ¹⁰ compared to the use amount can be higher . Therefore, when concentrated boron is used, if the same neutron absorption capacity is used, a square pipe having a thinner plate thickness than that when natural boron is used as it is can be used. For this reason, when concentrated boron is used, the same neutron absorption ability can be obtained with a thinner plate pressure. Therefore, when it is desired to reduce the weight of the recycled fuel assembly storage basket, it is preferable to use concentrated boron. On the other hand, neutron absorption capacity can be increased by adding the same amount of concentrated boron as when natural boron or B ₄ C is used as it is. Therefore, even when storing highly burned recycled fuel assemblies, safety against criticality is ensured. Enough can be secured.

For the Al or Al alloy, pure aluminum ingot, Al-Cu aluminum alloy, Al-Mg aluminum alloy, Al-Mg-Si aluminum alloy, Al-Zn-Mg aluminum alloy, Al-Fe aluminum An alloy or the like can be used. Further, B ₄ C, B ₂ O ₃ or the like can be used for the B or B compound. Here, the addition amount of boron based on B ₄ C with respect to aluminum is preferably 1.5% by mass or more and 9% by mass or less. This is because sufficient neutron absorption capacity cannot be obtained when the content is 1.5% by mass or less, and elongation with respect to tension decreases when the content exceeds 9% by mass. Furthermore, from the viewpoint of improving workability, it is preferable that the amount of boron added is 7% by mass or less. Needless to say, more concentrated B ¹⁰ can be added if concentrated boron is used.

  As the neutron absorbing material other than B, a material having a large neutron absorption cross section such as cadmium, hafnium, rare earth element, etc. can be used in addition to boron. As the rare earth element, oxides such as europium, dysprosium, samarium, and gadolinium can be used. Here, in the case of a boiling water reactor (BWR), B or a B compound is mainly used, but in the case of a pressurized water reactor (PWR), an Ag—In—Cd alloy is used. The composition of the Ag-In-Cd alloy is generally 15% by mass of In and 5% by mass of Cd.

In this production example, high energy ball milling (mechanical alloying, hereinafter referred to as MA) is used for mixing Al or Al alloy powder and B or B compound powder. Thereby, the Al powder and the B ₄ C powder were refined, and the B ₄ C powder was dispersed as uniformly as possible in the Al powder. As a result, the strength of the storage square pipe 3 can be improved while suppressing segregation of the B ₄ C powder. A general rolling mill, a rocking mill, and an attritor mill can be used for the high energy ball milling.

In the process of MA, the introduced Al is crushed and folded by receiving the impact of the ball used for MA to become a flat shape. On the other hand, the B ₄ C powder is crushed by ball milling, and its particle size is reduced to about 0.5 μm to 1.0 μm and is uniformly rubbed into the Al matrix. For this reason, since fine dispersed particles are uniformly dispersed in the base material, the Al alloy obtained by sintering this powder has excellent strength. After the completion of MA, the mixed powder is taken out from the container, and the process proceeds to a hot press process and an extrusion process to form the storage square pipe 3 and the like.

If MA is used in this way, the B ₄ C powder can be refined and homogenized and dispersed in the matrix of Al powder, so that the strength of the storage square pipe 3 and the like can be improved. Specifically, the strength can be improved by about 1.2 to 1.5 times as compared with a storage square pipe or the like manufactured by a normal mixer. For this reason, it is particularly useful when used as a square pipe of a PWR cask having a large recycled fuel assembly mass. Furthermore, since the B ₄ C powder having high hardness is finely and uniformly dispersed in the matrix, thereby preventing the aggregation of the B ₄ C powder, the extrudability can be improved. For this reason, there is also an effect of reducing wear of the extrusion die. Furthermore, when performing MA, you may make it throw in organic solvents, such as alcohol. By doing in this way, the compound of an organic solvent and aluminum is added, and the effect that the intensity | strength and ductility of the square pipe 3 for accommodation can also be acquired.

  According to MA, as a result of improving the strength as described above, extrusion molding becomes more difficult. Therefore, when the basket 1a or the like according to the present invention is manufactured using B-Al material by MA, the storage square pipe 3, the spacer square pipe 20, the support member 10 and the like having a relatively easy shape are extruded. It is desirable that the basket 1a and the like be formed by combining them. In particular, since the strength of the B-Al material by MA is high, it is extremely difficult to actually extrude the PWR square pipe provided with the flux trap using this material. Accordingly, the basket for storing the recycled fuel assembly for PWR can hardly be manufactured at present unless the basket is structured as in the basket 1a (see FIG. 1) according to the present invention. For this reason, the basket 1a and the like according to the present invention are extremely significant.

  Next, the mixed powder is put in a rubber case and sealed, and a high pressure is applied uniformly from all directions at room temperature by CIP (Cold Isostatic Press) to perform powder molding (step S204). By applying pressure uniformly from all directions by CIP, a high-density molded product with little variation in molding density can be obtained. Moreover, it can replace with CIP and a preforming body can also be shape | molded by the high pressure press of a uniaxial direction. According to this, it is not necessary to put the mixed powder in the rubber case and evacuate it, and it is sufficient to put the mixed powder in the mold and press the mold, so that it can be preformed relatively easily.

Next, the preform is placed in a sintering furnace, evacuated, and sintered under no pressure and in a vacuum state (step S205). The degree of vacuum during vacuum sintering is, for example, about 10 ⁻¹ Torr, and the temperature is 550 ° C. to 600 ° C. Further, the sintering temperature is stepped up at a predetermined temperature pitch while deaeration. The powders temporarily hardened by this vacuum sintering are fused to form a neck, which becomes a billet for extrusion. Moreover, since it vacuum-sinters in a non-pressurized state, it is not pressurized like HIP or hot press. Therefore, the mass density of the sintered body is almost the same as that at the time of preforming. Furthermore, the billet is prevented from being oxidized by vacuum sintering and canning can be omitted, so that the cost of cans can be saved, and cutting processes such as external cutting and end face cutting for removing cans are not necessary, and the accompanying cans Manufacturing processes such as encapsulation can be omitted.

  When manufacturing the storage square pipe 3, the billet after sintering is hot-extruded using a porthole extruder (step S206). As the extrusion conditions in this case, the heating temperature is, for example, 500 ° C to 520 ° C. The porthole extruder is equipped with a high frequency coil for induction heating around the container. By flowing an RF (Radio Frequency) current through the high frequency coil, the billet in the die can be induction heated. The induction heating is performed by generating an induced current in the billet. However, since the billet to be heated is in a state where the mixed powders are fused in the vacuum sintering step, the induced current is generated in the entire billet. Can be efficiently heated. In addition, the efficiency of induction heating is dramatically increased by vacuum sintering, and the advantage that the billet extrusion speed can be improved is obtained.

  The billet induction-heated in the container is pushed from behind by a punch and pushed out as a storage square pipe 3 having a predetermined extrusion shape by a die. Since the voids between the billet powder particles are crushed by the extrusion molding, the mass density of the storage square pipe 3 becomes approximately 100% after the extrusion molding. After extrusion molding, tensile correction is performed (step S207), and the unsteady part and the evaluation part are cut (step S208) to obtain a product. The completed storage square pipe 3 has a quadrangular cross section as shown in FIG. In this description, a porthole extruder having a high compression ratio and suitable for extrusion of a complex material such as aluminum is used. However, the extruder is not limited to this. For example, a fixed or moving mandrel method may be employed. In addition to direct extrusion, hydrostatic extrusion may be performed, and can be appropriately selected within the range possible for those skilled in the art. Furthermore, although the production efficiency is low, the billet may be batch-processed in a heating furnace instead of the induction heating. In addition, the spacer square pipe 20 and the support member 10 (see FIG. 1 and the like) can be manufactured in the same manner as the storage square pipe 3 by changing the extrusion die.

  As described above, the recycled fuel assembly storage basket and the recycled fuel assembly storage container according to the present invention are useful for transporting and storing the recycled fuel assembly, and are particularly difficult to extrude such as B-Al material. It is suitable for efficient production even when materials are used.

FIG. 3 is a plan view showing a part of a recycled fuel assembly storage basket according to the first embodiment. It is explanatory drawing which shows the square pipe for accommodation which accommodates a recycle fuel assembly. It is explanatory drawing which shows the square pipe for accommodation which accommodates a recycle fuel assembly. FIG. 5 is an explanatory diagram illustrating a support member according to the first embodiment. FIG. 5 is an explanatory diagram illustrating a support member according to the first embodiment. FIG. 5 is an explanatory diagram illustrating a support member according to the first embodiment. It is explanatory drawing which shows the square pipe for spacers concerning Example 1. FIG. It is explanatory drawing which shows the square pipe for spacers concerning Example 1. FIG. 1 is a perspective view illustrating an entire basket according to Example 1. FIG. It is a perspective view which shows the cask which is an example of a recycle fuel assembly storage container. FIG. 6 is a plan view of the cask shown in FIG. 6 is a plan view showing a part of a basket according to a first modification of Example 1. FIG. FIG. 6 is a plan view showing a spacer square pipe according to a first modification of the first embodiment. 6 is a plan view showing a part of a basket according to a second modification of Example 1. FIG. 6 is a plan view showing a spacer square pipe according to a second modification of Example 1. FIG. It is a top view which shows the other square pipe for spacers which concerns on the 2nd modification of Example 1. FIG. 6 is a plan view showing a part of a basket according to a third modification of Example 1. FIG. FIG. 10 is a plan view showing a support member according to a third modification of Example 1. 6 is an enlarged view showing a connecting portion of a support member according to a third modification of Example 1. FIG. FIG. 6 is a plan view showing a square pipe for spacers according to a third modification of Example 1. It is an enlarged view which shows the connection part of the square pipe for spacers which concerns on the 3rd modification of Example 1. FIG. FIG. 12 is a plan view showing another connection structure according to a third modification of Example 1. FIG. 12 is a plan view showing another connection structure according to a third modification of Example 1. 6 is an explanatory view showing a recycled fuel assembly storage basket according to Embodiment 2. FIG. It is explanatory drawing which shows the combination of the spacer member of the basket for recycled fuel assembly storage which concerns on Example 2. FIG. It is explanatory drawing of the spacer member which comprises the basket which concerns on Example 2. FIG. It is explanatory drawing of the spacer member which comprises the basket which concerns on Example 2. FIG. 10 is a plan view showing a part of a basket according to a first modification of Example 2. FIG. 6 is a plan view of a spacer member that constitutes a basket according to a first modification of Example 2. FIG. 6 is a plan view of a spacer member that constitutes a basket according to a first modification of Example 2. FIG. 10 is a plan view showing a part of a basket according to a second modification of Example 2. FIG. 10 is a plan view of a spacer that constitutes a basket according to a second modification of Example 2. FIG. 6 is a plan view showing a part of a basket according to Embodiment 3. FIG. FIG. 6 is a plan view of a cross member that constitutes a basket according to a third embodiment. 10 is a plan view showing a part of a basket according to a first modification of Example 3. FIG. 10 is a plan view showing a part of a basket according to a second modification of Example 3. FIG. 10 is a plan view showing a basket according to Embodiment 4. FIG. It is the side view seen from the arrow A direction of FIGS. It is the side view seen from the arrow B direction of FIGS. It is explanatory drawing which shows the 1st square pipe-shaped member which comprises the basket which concerns on Example 4. FIG. It is explanatory drawing which shows the 2nd square pipe-shaped member which comprises the basket which concerns on Example 4. FIG. It is explanatory drawing which shows the wedge-shaped spacer which comprises the basket which concerns on Example 4. FIG. FIG. 10 is a perspective view showing a basket according to a modification of Example 4. FIG. 10 is a perspective view showing a basket according to another modification example of the fourth embodiment. FIG. 10 is a side view showing a plate-like member that constitutes a basket according to a modification of Example 4; FIG. 10 is a side view showing a notch portion of a plate-like member that constitutes a basket according to a modification of Example 4. FIG. 10 is a side view showing a basket according to a modified example of the fourth embodiment. FIG. 10 is a cross-sectional view showing another configuration example of a plate-like member provided in a basket according to a modification example of Example 4. 10 is a perspective view showing a part of a basket according to Embodiment 5. FIG. 10 is a plan view showing a part of a basket according to Embodiment 5. FIG. It is explanatory drawing which shows the square spacer which comprises the basket which concerns on Example 5. FIG. It is explanatory drawing which shows the other square pipe-shaped member applicable to the basket of Example 5. FIG. It is explanatory drawing which shows the other square pipe-shaped member applicable to the basket of Example 5. FIG. 10 is a plan view showing a part of a basket according to Embodiment 6. FIG. 10 is a plan view showing a basket according to a first modification of Example 6. FIG. FIG. 29 is a plan view showing a basket according to a second modification example of the sixth embodiment. FIG. 22 is a plan view showing a basket according to a third modification of Example 6. FIG. 16 is a plan view showing a basket according to a fourth modification of Example 6. FIG. 16 is a plan view showing a basket according to a fourth modification example of Example 6. FIG. 16 is a plan view showing a basket according to a fourth modification of Example 6. It is a flowchart which shows the manufacturing method of the square pipe for storage concerning this invention.

Explanation of symbols

1a, 1b, 1c, 1d, 1e, 1f, 1g, 1h, 1i, 1j, 1k, 1l, 1m, 1n, 1o, 1p, 1q, basket 3 storage square pipe 10, 13 support member 20, 21, 22, 23, 23a Square pipe for spacer 30, 31, 32, 33 Spacer member 40, 41, 42 Cross member 50, 51, 52 Square pipe member 53 First square pipe member 54 Second square pipe member 55 Wedge spacer 200 Cask

Claims (19)

Storage square pipes arranged in a grid and storing the recycled fuel assemblies inside,
A spacer disposed between the storage square pipes;
A basket for storing a recycled fuel assembly, comprising: Storage square pipes arranged in a grid and storing the recycled fuel assemblies inside,
A spacer square pipe disposed between the storage square pipes and abutting against an outer surface of the storage square pipe;
A support member having a quadrangular cross section disposed outside the corner of the storage square pipe;
A basket for storing a recycled fuel assembly, comprising:   The recycled fuel assembly storage basket according to claim 2, wherein the support member has a through hole extending in a longitudinal direction thereof.   The recycled fuel assembly storage basket according to claim 2, wherein the support member and the spacer square pipe are connected to each other.   3. The concave portion toward the longitudinal direction of the support member is formed outside the corner portion of the support member, and the corner outer side of the storage square pipe is fitted into the concave portion. 4. The recycled fuel assembly storage basket according to 3.   The recycled fuel assembly storage basket according to any one of claims 2, 3, and 5, wherein the spacer square pipe has a longitudinal end projecting therefrom.   7. The rib parallel to the short side in the cross section perpendicular to the longitudinal direction of the square pipe for spacers is provided inside the square pipe for spacers. Recycled fuel assembly storage basket described in 1. Storage square pipes arranged in a grid and storing the recycled fuel assemblies inside,
A spacer member including a flat plate and ribs provided on both sides of the flat plate in a direction perpendicular to the flat plate;
And the rib is in contact with the outer surface of the storage square pipe, and the spacer member is disposed between the storage square pipes. Storage square pipes arranged in a grid and storing the recycled fuel assemblies inside,
The first flat plate portions arranged in parallel and alternately, and the first ribs orthogonal to the first flat plate portion and connecting the first flat plate portions arranged alternately, and further including the storage A first spacer member arranged in a specific direction between the square pipes;
The second flat plate portions arranged in parallel and alternately, and the second ribs orthogonal to the second flat plate portion and connecting the second flat plate portions arranged alternately, and further including the second flat plate portions, A second spacer member disposed between the storage square pipes such that two flat plate portions are orthogonal to the first flat plate portion of the first spacer member;
The first flat plate portion and the second flat plate portion are in contact with the outer side surface of the storage square pipe, and the long side length in a cross section perpendicular to the axis of the second spacer member is the first flat plate portion. A recycled fuel assembly storage basket, wherein the length is longer than the long side length in a cross section perpendicular to the axial direction of one spacer member. Storage square pipes arranged in a grid and storing the recycled fuel assemblies inside,
A plate-like spacer member that is disposed between the storage square pipes and has a through-hole inside, and a long side end is formed in a step shape,
And a recycle fuel assembly storage basket, wherein the long side ends of the spacer member are combined. A storage square pipe that stores the recycled fuel assembly inside,
A cross member whose cross section perpendicular to the longitudinal direction has a cross shape, and a hole in the longitudinal direction is formed inside,
A cross-shaped space for arranging the storage square pipe is configured by abutting end portions on the long side of the cross member, and the storage square pipe is disposed in the lattice-shaped space. Recycled fuel assembly storage basket.   The said cross member is provided with the said long side side edge part in which the recessed part was formed, and the said long side side edge part in which the convex part was formed, The said recessed part and a convex part are combined, It is characterized by the above-mentioned. Recycled fuel assembly storage basket described in 1.   The recycle fuel assembly according to claim 11, wherein the cross member includes a long side end portion having a cross section perpendicular to a longitudinal direction formed in a step shape, and the long side end portions are combined with each other. Storage basket. A recycled fuel assembly storage basket in which square pipes for storing recycled fuel assemblies are arranged in a space formed by alternately stacking a plurality of stages of rectangular pipe-like members,
First square pipe-like members arranged in the same direction every other stage;
A second square pipe-like member arranged in the same direction every other stage and stacked perpendicularly to the first square pipe-like member;
A storage square pipe that is disposed in a space surrounded by the first square pipe-shaped member and the second square pipe-shaped member and stores a recycled fuel assembly therein;
Recycling characterized in that at least one of the first rectangular pipe-shaped member and the second rectangular pipe-shaped member is disposed such that its tube axis is inclined with respect to the bottom surface of the recycled fuel assembly storage basket. Fuel assembly storage basket.   The drainage passage is formed in at least one of the long side end of the first square pipe member or the long side end of the second square pipe member. Recycled fuel assembly storage basket described in 1. Recycled fuel assembly storage basket configured by combining plate members,
The plate-like members are stacked in a plurality of stages by combining plate-like members having notches formed at the long side end portions and having through-holes penetrating in the longitudinal direction and orthogonal to each other. The recycle fuel assembly is stored in a lattice-like space surrounded by a plurality of the plate members, the plate member being inclined with respect to the bottom surface of the recycled fuel assembly storage basket. Fuel assembly storage basket. A storage square pipe for storing the recycled fuel assembly;
A square pipe-like member having a drainage passage formed at the end on the long side,
Recycled fuel assembly storage basket, wherein the square pipe-like members are alternately stacked in a plurality of stages, and the storage square pipes are disposed in a lattice-like space surrounded by the square pipe-like members. .   The storage square pipe, the spacer, the spacer square pipe, the support member, and other constituent members of the recycled fuel assembly storage basket are boron or an aluminum alloy containing a boron compound, or an aluminum alloy. The recycled fuel assembly storage basket according to any one of claims 1 to 17, wherein at least one of the constituent members is an aluminum alloy containing boron or a boron compound. A torso comprising an opening and a cavity;
A lid attached to the opening to seal the cavity;
The recycled fuel assembly storage basket according to any one of claims 1 to 18, which is disposed in the cavity.
A recycled fuel assembly storage container, comprising:

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