JP2024014105A - Basket for metal cask - Google Patents

Abstract

An object of the present invention is to provide a basket for a metal cask that can achieve low material costs and keep the product price of the metal cask low. [Solution] A first basket plate group 21A consisting of a plurality of basket plates 21 arranged parallel to each other in one direction, and a plurality of baskets arranged parallel to each other in a direction perpendicular to the one direction. A second basket plate group 21B consisting of plates 21 is provided, and is configured as a laminate in which these plates are alternately stacked in the axial direction. The laminate includes a basket plate 21 formed of a boron-added steel plate to which boron is added, and a basket plate 21 formed of a boron-free steel plate to which boron is not added. [Selection diagram] Figure 1

Description

The present invention relates to a metal cask basket that can reduce the usage rate of neutron absorbing material.

Conventionally, a storage method using metal casks has been known as a method for stably storing spent fuel within or outside the premises of a nuclear power plant. The metal cask includes a basket inside the barrel body for storing the spent fuel assembly.
The basket includes a plurality of lattice-shaped compartments and is configured to partition and store spent fuel assemblies one by one.
Conventionally, as a structure for fixing a basket to a trunk body, the structure disclosed in Patent Document 1 is known. In the metal cask of Patent Document 1, a plurality of grooves are formed on the inner surface of the barrel body, and the basket is fixed to the barrel body by inserting the end of the basket plate forming the basket into each groove. The basket plate of Patent Document 1 is made of the same boron-added steel plate containing boron as a neutron absorbing material.

On the other hand, it is also known that a basket is constructed by combining a basket plate formed of a boron-added steel plate and a basket plate formed of a boron-free steel plate to which boron is not added (for example, see Patent Document 2). .

Japanese Patent Application Publication No. 2007-171135 Japanese Patent Application Publication No. 2007-212385

In general, boron is a rare resource, and boron-added steel sheets are special materials, so material availability is low and prices are high. In the metal cask basket of Patent Document 2, a boron-free steel plate to which boron is not added is used in part, but the basket plate forming the basket extends throughout the axial direction of the barrel body. Due to the large size, the locations where the boron-free steel plate can be used may be limited, and as a result, the material cost may become expensive.

An object of the present invention is to provide a basket for a metal cask that can solve the above-mentioned problems, reduce material costs, and keep the product price of the metal cask low.

In order to solve the above problems, the metal cask basket of the present invention is provided in the main body of a cylindrical metal cask for storing or transporting spent fuel, and has a plurality of lattices for storing the spent fuel. A basket for a metal cask forming a plurality of compartments, the first basket plate group consisting of a plurality of basket plates aligned parallel to each other in a direction, and a direction orthogonal to the first direction. a second basket plate group consisting of a plurality of basket plates arranged parallel to each other toward It is composed of a laminate, and the laminate includes the basket plate formed of a boron-added steel plate to which boron is added, and the basket plate formed of a boron-free steel plate to which boron is not added. It is characterized by becoming.

According to the metal cask basket according to the present invention, material costs can be reduced, and the product price of metal casks can be kept low.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic cross-sectional view showing a barrel body and a basket to which a metal cask basket according to a first embodiment of the present invention is applied. FIG. 2 is a diagram showing a barrel body and a basket to which the metal cask basket according to the first embodiment of the present invention is applied, and is a schematic longitudinal sectional view taken along the line II-II in FIG. 1. FIG. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded perspective view showing a part of the structure of a barrel body and a basket to which a metal cask basket according to a first embodiment of the present invention is applied. 2 is a diagram showing a barrel body and a basket to which a metal cask basket according to a second embodiment of the present invention is applied, and is a schematic vertical sectional view corresponding to a cross section taken along line II-II in FIG. 1. FIG. 2 is a diagram showing a barrel body and a basket to which a metal cask basket according to a third embodiment of the present invention is applied, and is a schematic vertical sectional view corresponding to a cross section taken along line II-II in FIG. 1. FIG. 2 is a diagram showing a barrel body and a basket to which a metal cask basket according to a fourth embodiment of the present invention is applied, and is a schematic vertical sectional view corresponding to a cross section taken along line II-II in FIG. 1. FIG. 2 is a diagram showing a barrel body and a basket to which a metal cask basket according to a fifth embodiment of the present invention is applied, and is a schematic vertical cross-sectional view corresponding to a cross section taken along line II-II in FIG. 1. FIG.

Embodiments of the present invention will be described in detail below with reference to the drawings as appropriate. In each embodiment, the same parts are given the same reference numerals, and redundant explanations will be omitted. In the description of each embodiment, the term "axial direction" refers to a direction parallel to the central axis of the cylindrical metal cask, and the term "radial direction" refers to the axial direction. shall represent the direction perpendicular to . Note that in FIGS. 2 and 4 to 7, the cross section of the basket plate on the side perpendicular to the plane of the paper is shown as a partial cross section of the portion that engages with the slit.

(First embodiment)
As shown in FIG. 1, the metal cask 10 is used to store or transport spent fuel assemblies 11 (hereinafter referred to as "fuel assemblies 11"; see FIG. 4). The metal cask 10 has a metal cask basket 20 (hereinafter simply referred to as a “basket 20 ).

The trunk body 12 has a function of shielding radiation (gamma rays) generated from the fuel assembly 11. The trunk body 12 is, for example, a bottomed cylindrical container made of carbon steel. The outer periphery of the trunk body 12 is filled with a neutron shielding material (not shown). As shown in FIG. 3, a plurality of grooves 15 (see FIG. 3) are formed on the inner surface of the trunk body 12, extending in the direction of the axis O1 of the trunk body 12 (see FIG. 2). The plurality of grooves 15 function as insertion grooves for the basket plate 21 that constitutes the basket 20.
Note that the upper opening of the trunk body 12 is closed by a plurality of lid members (not shown).

Next, the basket 20 will be explained. The basket 20 has a criticality prevention function and a shielding function. As shown in FIGS. 2 and 3, the basket 20 is constructed by assembling a plurality of plate-shaped basket plates 21 orthogonally in a lattice shape to form a plurality of compartments 13 (see FIG. 1). Each partition 13 has a square cylindrical opening when viewed in cross section (viewed from the axis O1 direction of the trunk body 12), and has a size that allows the fuel assembly 11 to be accommodated therein.

As shown in FIG. 3, the basket 20 includes a first basket plate group 21A and a second basket plate group 21B, which are stacked alternately in the direction of the axis O1 of the trunk body 12 to form a laminate ( It is composed of a laminated structure. As shown in FIGS. 1 to 3, the first basket plate group 21A includes a plurality of basket plates 21 (in this embodiment, 10 sheets (indicated by reference numerals 21a to 21j). The second basket plate group 21B includes a plurality of basket plates 21 (10 in this embodiment, reference numerals 21k to 21k in this embodiment) arranged parallel to each other in a direction perpendicular to the first direction (horizontal direction on the paper surface of FIG. 1). 21t). Note that, hereinafter, the basket plates 21a to 21j and 21k to 21t may be simply referred to as the basket plate 21 (one by one).

As shown in FIGS. 2 and 3, the first basket plate group 21A and the second basket plate group 21B engage each other with cut grooves 23 formed at the intersection of the basket plates 21 facing each other in the direction of the axis O1. By doing this, they are assembled into a grid. Below, each group of the first basket plate group 21A to be stacked will be described from the lower side (bottom side) in the axis O1 direction of the trunk body 12 to the upper side (opening side) in the axis O1 direction, as shown in FIG. The stacked second basket plate groups 21B are referred to as odd-numbered A1 groups to A9 groups in the stacking order, and the even-numbered groups B2 to B8 are also referred to as even-numbered groups in the stacking order from the bottom side to the opening side. It is called a group.

Of the first basket plate group 21A, the basket plates 21a to 21j of the A9 group (only the one with reference numeral 21f is shown in FIG. 2, and the same applies hereinafter) arranged at the top in the direction of the axis O1 are the basket plates of the A3 group to the A7 group. The height dimension is approximately 1/2 that of the plates 21a to 21j. Further, among the first basket plate group 21A, the basket plates 21a to 21j of the A1 group, which are arranged at the bottom in the direction of the axis O1, have a somewhat smaller height than the basket plates 21a to 21j of the A3 groups to A7 groups. It has dimensions.

On the other hand, of the second basket plate group 21B, the basket plates 21k to 21t of the B4 group to B8 group (only the one with the reference numeral 21p is shown in FIG. 2, the same applies hereinafter) are the A3 group to A7 group of the first basket plate group 21A. It has the same height dimension as the basket plates 21a to 21j. Furthermore, among the second basket plate group 21B, the basket plates 21k to 21t of the B2 group, which are disposed at the bottom in the direction of the axis O1, have a somewhat larger height than the basket plates 21k to 21t of the B4 groups to B8 groups. It has the following dimensions.
In addition, in the first basket plate group 21A and the second basket plate group 21B, the height dimensions of the respective basket plates 21a to 21j and 21k to 21t can be changed and set as appropriate for each group.

Each basket plate 21 has a rectangular shape and is provided with a plurality of cut grooves 23 (see FIGS. 2 and 3) for engagement at equal intervals in the longitudinal direction. The interval between each cut groove 23 corresponds to the width of the cross section of the fuel assembly 11 to be accommodated. The depth of each cut groove 23 is set to an appropriate dimension, for example, approximately 1/2 to 1/2 of the height of each basket plate 21, so that the basket plates 21 of each group can be stacked without gaps in the direction of the axis O1. It is set to 1/4 the size.

The basket plate 21 of this embodiment is formed of a boron-added steel plate made of a stainless steel plate containing boron (boron with high absorption capacity as a neutron absorbing material) and a boron-free steel plate made of a stainless steel plate that does not contain boron. There are two types: That is, the laminate that constitutes the basket 20 is composed of a basket plate 21 made of a boron-added steel plate and a basket plate 21 made of a boron-free steel plate. The amount of boron added in the boron-added steel sheet is preferably about several percent by mass.
In this embodiment, as shown in FIG. 1, basket plates 21 made of boron-free steel plates are arranged in the radial direction from the axis O1 of the trunk body 12 in each first basket plate group 21A and each second basket plate group 21B. This is applied to the basket plates 21a, 21j, 21k, and 21t that are arranged at the farthest positions on the outside. The other basket plates 21 are made of boron-added steel plate.
That is, by forming the basket plates 21a, 21j, 21k, and 21t, which are arranged at positions that do not easily affect the criticality prevention function and shielding function of the basket 20, from boron-free steel plates, material costs can be reduced. ing.
Note that the boron-added steel plate is not limited to being made of a stainless steel plate, and can be made of various materials.
Here, the boron-added steel plate has a stamp indicating that boron is added. Note that boron-free steel sheets are not stamped and can be visually distinguished from boron-added steel sheets.

When assembling the basket 20 to the trunk body 12, the basket plates 21 of the A1 group are inserted into the inner surface of the trunk body 12 along the grooves 15 (see FIG. 3) of the trunk body 12. Thereafter, each basket plate 21 is inserted in the order of B2 group, A3 group, B4 group to A9 group, and the respective cut grooves 23 are engaged with each other. As a result, the basket plates 21 of each group are stacked in the direction of the axis O1, and the basket 20 is assembled within the trunk body 12.

According to the metal cask basket 20 of this embodiment described above, since the basket plates 21a, 21j, 21k, and 21t are formed of boron-free steel plates, the entire basket plate 21 is made of boron-added steel plates. It is possible to achieve lower material costs compared to the case where the structure is configured. Thereby, the product price of the metal cask 10 can be kept low.

In addition, the basket plates 21a, 21j, 21k, and 21t formed of boron-free steel plates are disposed at the farthest positions radially outward from the axis O1 of the trunk body 12, so that the criticality prevention function of the basket 20 is improved. And the shielding function can be suitably maintained.

Further, since the boron-added steel plate is stamped, and the boron-free steel plate is not stamped, when assembling the basket 20, the basket plate 21 can be assembled in the proper position while visually checking these. Therefore, incorrect assembly can be prevented and the assembly is excellent.

(Second embodiment)
A metal cask basket according to a second embodiment will be described with reference to FIG. 4. FIG. 4 is a diagram showing a barrel body and a basket to which a metal cask basket according to a second embodiment of the present invention is applied, and is a schematic vertical sectional view corresponding to a cross section taken along line II-II in FIG. be. The metal cask basket 20 of this embodiment differs from the first embodiment in that a basket plate 21 made of a boron-free steel plate is arranged to correspond to the configuration of the fuel assembly 11, and other configurations are changed. There isn't.

As shown in FIG. 4, the fuel assembly 11 includes a fuel effective portion 11a that is a region filled with fuel, and a non-fuel effective portion 11b that is located above and below the fuel effective portion 11a and does not correspond to the fuel effective portion 11a. , 11b. A line marked with the symbol BO in the figure indicates the boundary between the fuel effective portion 11a and the non-fuel effective portion 11b.

In this embodiment, the basket plate 21 made of a boron-free steel plate is used as the basket plate 21a to 21j of the A7 group and the A9 group (see FIGS. 1 and 2, In FIG. 4, only the one with reference numeral 21f is shown, the same applies hereafter), and the basket plates 21k to 21t of the B8 group (see FIGS. 1 and 2; in FIG. 4, only the one with reference numeral 21p is shown, the same below). In FIG. 4, dark dot patterns are added to make the A7 group, A9 group, and B8 group clear.
The basket plates 21 arranged in the other groups A1 to A5 and groups B2 to B6 are made of boron-added steel plates, except for the basket plates 21a, 21j, 21k, and 21t (boron-free steel plates).

In addition, since each basket plate 21 of the B6 group is a plate disposed across the boundary BO between the non-fuel effective part 11b and the fuel effective part 11a on the upper side, the criticality prevention function and the shielding function are taken into consideration. It is made of boron-added steel sheet. In addition, even in the case of straddling the boundary BO in this way, if the shielding function can be ensured, each basket plate 21 in the straddling portion can be made of a boron-free steel plate.

According to the metal cask basket 20 of the present embodiment described above, each basket plate 21 disposed corresponding to the non-fuel effective portion 11b on the upper side of the fuel assembly 11 is made of a boron-free steel plate. Cost reduction can be achieved. Thereby, the product price of the metal cask 10 can be kept low.

Moreover, since the basket plate 21 formed of a boron-free steel plate is disposed in the non-fuel effective portion 11b on the upper side of the fuel assembly 11, the criticality prevention function and shielding function of the basket 20 can be suitably maintained.

(Third embodiment)
A metal cask basket according to a third embodiment will be described with reference to FIG. FIG. 5 is a diagram showing a barrel body and a basket to which a metal cask basket according to a third embodiment of the present invention is applied, and is a schematic vertical sectional view corresponding to a cross section taken along line II-II in FIG. be. The difference between the metal cask basket 20 of this embodiment and the second embodiment is that, in conjunction with the structure of the fuel assembly 11, a basket plate 21 (hereinafter referred to as "added steel") is formed of a boron-added steel plate with a different boron addition rate. The only difference is that basket plates 21 with different ratios are arranged, but the other configurations are unchanged. In FIG. 5, groups in which basket plates 21 having different addition rates are arranged are marked with a thin dot pattern.

As shown in FIG. 5, the basket plates 21 having different addition rates are arranged on the upper side of the basket 20 at a position straddling the boundary BO between the fuel effective portion 11a and the non-fuel effective portion 11b of the fuel assembly 11. This is applied to the basket plates 21k to 21t of the B6 group (see FIGS. 1 and 2; in FIG. 5, only the one designated by the reference numeral 21p is shown, and the same applies hereinafter). Furthermore, the basket plates 21 having different addition rates are the basket plates 21a to 21j of the A1 group (Fig. 1 and 2; in FIG. 5, only the reference numeral 21f is shown; the same applies hereafter). In other words, the basket plates 21 with different addition rates are arranged in the boundary BO between the fuel effective part 11a and the non-fuel effective part 11b of the fuel assembly 11, and in the area near the boundary BO (the area where the neutron dose equivalent rate is relatively small). ).

The basket plates 21 having different addition rates have a lower boron addition rate (lower boron addition amount) than the basket plates 21 made of other boron-added steel plates in the fuel effective portion 11a. The basket plates 21 with different addition rates are marked with markings different from the markings given on the boron-added steel plates, so that they can be visually distinguished during assembly.

According to the metal cask basket 20 of the present embodiment described above, each basket plate 21 disposed corresponding to the non-fuel effective portion 11b on the upper side of the fuel assembly 11 is made of a boron-free steel plate; The basket plates 21 of the B6 group and the A1 group, which are arranged at positions straddling the boundary BO between the upper and lower sides, are made of boron-added steel plates with different (lower) addition rates. Therefore, it is possible to achieve a reduction in material costs while suitably achieving a shielding function in a region where the neutron dose equivalent rate is relatively small near the boundary portion BO between the upper side and the lower side, while maintaining the criticality prevention function. Thereby, the product price of the metal cask 10 can be kept lower.

(Fourth embodiment)
A metal cask basket according to a fourth embodiment will be described with reference to FIG. 6. FIG. 6 is a diagram showing a barrel body and a basket to which a metal cask basket according to a fourth embodiment of the present invention is applied, and is a schematic vertical sectional view corresponding to a cross section taken along line II-II in FIG. be. The difference between the metal cask basket 20 of the present embodiment and the first to third embodiments is that the first basket plate group 21A and the second basket plate group 21B correspond to the boundary BO of the fuel assembly 11. There is no change in the other configurations except for the fact that the stacking boundary has been set with In FIG. 6, a group in which basket plates 21 made of boron-free steel plates are arranged is marked with a dark dot pattern.

As shown in FIG. 6, the first basket plate group 21A includes basket plates 21a to 21j of the A3a group and A3 group to A7a group corresponding to the fuel effective portion 11a of the fuel assembly 11 (see FIGS. 1 and 2, FIG. 21f is shown in the figure, and the same applies hereafter). In addition, the first basket plate group 21A includes basket plates 21a to 21j of the A1a group corresponding to the non-fuel effective portion 11b on the lower side of the fuel assembly 11 (see FIGS. 1 and 2; only the basket plate 21f is shown in FIG. 6). , hereinafter the same). Furthermore, the first basket plate group 21A includes basket plates 21a to 21j of the A9a group and A11a group corresponding to the non-fuel effective portion 11b on the upper side of the fuel assembly 11 (see FIGS. 1 and 2, and the reference numeral 21f in FIG. 6). (Only those shown in the diagram, the same applies hereafter).

On the other hand, the second basket plate group 21B includes basket plates 21k to 21t (see FIGS. 1 and 2) of the B4b group to B6 group corresponding to the fuel effective portion 11a of the fuel assembly 11, and only the one with reference numeral 21p is shown in FIG. , hereinafter the same). Further, the second basket plate group 21B includes basket plates 21k to 21t of the B2b group corresponding to the non-fuel effective portion 11b on the lower side of the fuel assembly 11 (see FIGS. 1 and 2, only the one with reference numeral 21p is shown in FIG. 6). , hereinafter the same). Furthermore, the second basket plate group 21B includes basket plates 21k to 21t (see FIGS. 1 and 2) of the B8b group corresponding to the non-fuel effective portion 11b on the upper side of the fuel assembly 11, and only the basket plate 21p in FIG. (as shown in the figure, the same applies hereafter).

The basket plates 21a to 21j of the A3a group and the A7a group corresponding to the fuel effective portion 11a of the fuel assembly 11 have a height dimension that is approximately 1/2 that of the basket plates 21a to 21j of the A3 group to A5 group. ing. Note that the basket plates 21k to 21t of the B4b group to B6 group corresponding to the fuel effective portion 11a are the same as the basket plates 21 of the A3 group to A5 group.

On the other hand, the basket plates 21 of the A1a group, A9a group, A11a group, B2b group, and B8b group corresponding to the non-fuel effective portion 11b of the fuel assembly 11 have a height corresponding to the area of the non-fuel effective portion 11b. The dimensions are set accordingly. With this configuration, the lamination boundary between the first basket plate group 21A and the second basket plate group 21B is made to coincide with the boundary portion BO.

In this embodiment, the basket plates 21 made of a boron-free steel plate are arranged in the basket plates 21a to 21j arranged in the A9a group, the A11a group, and the B8b group, which are arranged corresponding to the non-fuel effective portion 11b on the upper side. This is applied to the basket plates 21k to 21t arranged in the. In addition, basket plates 21 made of a boron-free steel plate are arranged in basket plates 21a to 21j arranged in the A1a group and basket plates 21a to 21j arranged in the B2b group, which are arranged corresponding to the non-fuel effective portion 11b on the lower side. Applies to 21k to 21t. In FIG. 6, these A9a group, A11a group, B8b group, A1a group, and B2b group are given a dark dot pattern so that they can be clearly seen. Note that each of the basket plates 21 arranged in the other groups A3a to A7a and groups B4b to B6 is made of boron-added steel plates, except for the basket plates 21a, 21j, 21k, and 21t (boron-free steel plates).

According to the metal cask basket 20 of the present embodiment described above, since the lamination boundary between the first basket plate group 21A and the second basket plate group 21B and the boundary portion BO match, the boron-free steel plate and The basket plate 21 made of a boron-added steel plate can be efficiently arranged. Thereby, it is possible to achieve a reduction in material costs, and the product price of the metal cask 10 can be kept low.

Further, since the basket plate 21 made of a boron-free steel plate is arranged in the non-fuel effective portions 11b on the upper and lower sides of the fuel assembly 11, the criticality prevention function and the shielding function of the basket 20 can be suitably maintained.

(Fifth embodiment)
A metal cask basket according to a fifth embodiment will be described with reference to FIG. 7. FIG. 7 is a diagram showing a barrel body and a basket to which a metal cask basket according to a fifth embodiment of the present invention is applied, and is a schematic vertical cross-sectional view corresponding to a cross section taken along line II-II in FIG. be. The metal cask basket 20 of this embodiment differs from the fourth embodiment in that basket plates 21 with different addition rates are arranged, and the other configurations are the same. In FIG. 7, groups in which basket plates 21 having different addition rates are arranged are marked with a thin dot pattern.

As shown in FIG. 7, the basket plates 21 having different addition rates are the basket plates 21a to 21j of the A3a group and A7a group (FIG. 1, 2, only the reference numeral 21f is shown in FIG. 7, and the same applies hereafter). That is, the basket plates 21 having different addition rates are arranged in a region near the boundary BO of the fuel assembly 11 (a region where the neutron dose equivalent rate is relatively small).

The basket plates 21 having different addition rates have a lower boron addition rate (lower boron addition amount) than the basket plates 21 made of other boron-added steel plates in the fuel effective portion 11a. The basket plates 21 with different addition rates are marked with markings different from the markings given on the boron-added steel plates, so that they can be visually distinguished during assembly.

According to the metal cask basket 20 of the present embodiment described above, each basket plate 21 arranged corresponding to the non-fuel effective portion 11b of the fuel assembly 11 is made of a boron-free steel plate, and in addition, the Each basket plate 21 of the A3a group and the A7a group adjacent to part BO is made of boron-added steel plates with different (lower) addition rates. Therefore, it is possible to achieve a reduction in material cost while suitably achieving a shielding function in a region where the neutron dose equivalent rate is relatively small near the boundary portion BO, and maintaining a criticality prevention function. Thereby, the product price of the metal cask 10 can be kept lower.
In addition, if the shielding function can be ensured, it is also possible to set the basket plates 21 of the B4b group and B6 group adjacent to the boundary part BO to be boron-added steel plates with different addition rates.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and each component can be modified as appropriate without departing from the spirit of the present invention.
For example, in the first, second, and fourth embodiments, one type of basket plate 21 made of boron-added steel plate is used, but the present invention is not limited to this, and the basket plate 21 has a different addition rate for each group. One or more types of plates 21 may be used. Further, in the third and fifth embodiments, groups in which basket plates 21 with different addition rates are arranged are provided, but in addition to this, one or more types of basket plates 21 with different addition rates are used for each group. It's okay. In these cases, it is preferable to arrange basket plates 21 with different addition rates corresponding to the neutron dose equivalent rates of the fuel assemblies 11 to be accommodated.
By configuring in this way, it is possible to suitably achieve a shielding function, maintain a criticality prevention function, and more preferably achieve a reduction in material costs.

Further, in the second to fifth embodiments, the basket plates 21a, 21j, 21k, and 21t are made of boron-free steel plates, but are not limited to this, and can be made of boron-added steel plates or with a different addition rate. Different basket plates 21 may be used.

Further, in each embodiment, the number of installed basket plates 21 in each group, height dimensions, etc. can be set as appropriate.

10 Metal cask 11 Fuel assembly (spent fuel assembly)
11a Fuel effective part 11b Non-fuel effective part 12 Trunk body 13 Compartment part 20 Basket for metal cask (basket, laminate)
21 Basket plate 21A First basket plate group 21B Second basket plate group BO Boundary portion O1 Axial center

Claims (11)

A basket for a metal cask, which is provided within the body of a cylindrical metal cask for storing or transporting spent fuel, and forms a plurality of lattice-shaped compartments for storing a plurality of the spent fuels, the basket comprising:
a first basket plate group consisting of a plurality of basket plates aligned parallel to each other in one direction;
a second basket plate group consisting of a plurality of basket plates aligned parallel to each other in a direction perpendicular to the first direction;
The first basket plate group and the second basket plate group are configured as a laminate in which the first basket plate group and the second basket plate group are alternately stacked in the axial direction,
The laminate is for a metal cask, characterized in that the basket plate is formed of a boron-added steel plate to which boron is added, and the basket plate is formed of a boron-free steel plate to which boron is not added. basket. The metal cask basket according to claim 1,
The basket plate for a metal cask, wherein the basket plate disposed at a position furthest radially outward from the axis of the metal cask among the plurality of basket plates is made of the boron-free steel plate. The metal cask basket according to claim 1,
A basket for a metal cask, wherein the boron-added steel plate has a different boron addition rate for each of the first basket plate group and the second basket plate group. The metal cask basket according to claim 1,
The spent fuel includes a fuel effective portion filled with fuel and a non-fuel effective portion that does not correspond to the fuel effective portion,
The plurality of basket plates of the first basket plate group and the second basket plate group, which are arranged at positions corresponding to the fuel effective portion, are made of the boron-added steel plate,
For a metal cask, wherein the plurality of basket plates of the first basket plate group and the second basket plate group, which are arranged at positions corresponding to the non-fuel effective portion, are made of the boron-added steel plate. basket. The metal cask basket according to claim 4,
The plurality of basket plates of the first basket plate group and the second basket plate group are arranged at positions corresponding to the boundary between the fuel effective part and the non-fuel effective part,
A basket for a metal cask, wherein the plurality of basket plates are made of a boron-added steel plate having a lower boron addition rate than the plurality of basket plates disposed at positions corresponding to the fuel effective portion. The metal cask basket according to claim 1,
The spent fuel includes a fuel effective portion filled with fuel and a non-fuel effective portion that does not correspond to the fuel effective portion,
For a metal cask, characterized in that a lamination boundary between the first basket plate group and the second basket plate group is set to correspond to a boundary between the fuel effective part and the non-fuel effective part. basket. The metal cask basket according to claim 6,
The plurality of basket plates of the first basket plate group and the second basket plate group, which are arranged at positions corresponding to the fuel effective portion, are made of the boron-added steel plate,
For a metal cask, wherein the plurality of basket plates of the first basket plate group and the second basket plate group, which are arranged at positions corresponding to the non-fuel effective portion, are made of the boron-added steel plate. basket. The metal cask basket according to claim 7,
The plurality of basket plates made of the boron-added steel plates disposed at positions corresponding to the fuel effective portions have different boron addition rates for each of the first basket plate group and the second basket plate group. Features a basket for metal casks. The metal cask basket according to claim 7,
Among the plurality of basket plates of the first basket plate group and the second basket plate group, which are arranged at positions corresponding to the fuel effective part, the plurality of basket plates adjacent to the boundary part are other than the plurality of basket plates. A basket for a metal cask, characterized in that the basket is made of a boron-added steel plate having a lower boron addition rate than the plurality of basket plates disposed at positions corresponding to the fuel effective portion. The metal cask basket according to claim 7,
Among the plurality of basket plates of the first basket plate group and the second basket plate group arranged at positions corresponding to the fuel effective portion, arranged at a position furthest radially outward from the axis of the metal cask. A basket for a metal cask, wherein the basket plate is made of the boron-free steel plate. The metal cask basket according to claim 1,
A basket for a metal cask, characterized in that the boron-added steel plate has a stamp indicating that boron is added.

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