JP2019191193A - Container for used nuclear fuel, and method for forming the container for used nuclear fuel - Google Patents

Abstract

To provide a container for used nuclear fuel and a method of forming the container for used nuclear fuel, which can efficiently suppress loads on inner parts to be added when a neutron blocking member thermally expands.SOLUTION: A container 1 for used nuclear fuel includes: a main body 2 in a practically cylindrical shape; an outer casing 3 over the main body 2; and a plurality of neutron blocking members 41 arranged between the main body 2 and the outer casing 3. The neutron blocking members 41 contain hollow parts 42, respectively, which extend in the axial direction of the main body 2. When the respective neutron blocking members 41 thermally expand, their expansion allowances are formed near the sides of the hollow parts 42, respectively.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a spent nuclear fuel container provided with a neutron shield having a hollow portion formed therein, and a method for producing a spent nuclear fuel container.

  Conventionally, a spent nuclear fuel container including an inner cylinder, an outer cylinder arranged so as to cover the inner cylinder, and a neutron shield disposed between the inner cylinder and the outer cylinder is known. The spent nuclear fuel container is stored in a state where the spent nuclear fuel is accommodated inside the inner cylinder. In the spent nuclear fuel container, neutrons are mainly shielded by a neutron shield in the radiation emitted from the spent nuclear fuel to be accommodated.

  As this kind of spent nuclear fuel container, a spent nuclear fuel container in which a neutron shield is divided into a plurality of parts in the axial direction of the inner cylinder and a gap (hollow part) is provided between the plurality of neutron shields has been proposed. (For example, see Patent Document 1 below).

In this spent nuclear fuel container, the neutron shield is formed of a resin material. When heat is generated in the spent nuclear fuel container, the neutron shield is thermally expanded. At this time, the neutron shield thermally expands so as to enter the hollow portion.
Thus, in this spent nuclear fuel container, the hollow portion between the plurality of neutron shields is a region that accommodates the elongation allowance when the neutron shield is thermally expanded.

JP 2006-226787 A

  In the conventional spent nuclear fuel container as described above, the hollow portion is arranged between a plurality of neutron shields arranged separately in the axial direction of the inner cylinder. On the other hand, the neutron shield is disposed outside the peripheral surface of the inner cylinder and extends from one end of the inner cylinder to the other end in the axial direction. Therefore, since the volume of the neutron shield changes so as to swell at all parts from one end to the other end in the axial direction of the inner cylinder, when the extension of the neutron shield is absorbed by the hollow portion, the inner cylinder Moreover, force may be applied to the outer cylinder. And in order to endure the force, an inner cylinder and an outer cylinder are thickened, and a weight may increase.

  The present invention has been made in view of the above circumstances, and a spent nuclear fuel container and a spent nuclear fuel container that can efficiently suppress the load on internal components when the neutron shield thermally expands. It aims at providing the manufacturing method of.

(1) A spent nuclear fuel container according to the present invention includes a main body, an outer cylinder, a plurality of heat transfer fins, and a plurality of neutron shields. The main body has a cylindrical shape capable of containing spent nuclear fuel. The outer cylinder covers the main body so as to face the outer peripheral surface of the main body with a space therebetween. The plurality of heat transfer fins extend from the outer peripheral surface of the main body toward the inner peripheral surface of the outer cylinder. The plurality of neutron shields are disposed between the plurality of heat transfer fins, and a hollow portion is formed therein. The hollow portion extends along an axial direction in which the axis of the main body extends in each of the plurality of neutron shields.

According to such a configuration, the hollow portion is formed inside each neutron shield and extends along the axial direction.
For this reason, when each neutron shield is thermally expanded, it is possible to efficiently secure a region of a hollow portion that becomes an expansion allowance of each neutron shield.
As a result, when each neutron shield is thermally expanded, it is possible to efficiently suppress the load on the main body, the heat transfer fin, and the outer cylinder.

(2) Moreover, the manufacturing method of the container for spent nuclear fuel which concerns on this invention includes an outer cylinder installation process, a type | mold arrangement | positioning process, and a shield formation process. In the outer cylinder installation step, spent nuclear fuel can be accommodated inside, and the outer cylinder is covered so as to cover the outer side with respect to the cylindrical main body in which a plurality of heat transfer fins extend outward from the outer peripheral surface. Put on. In the mold arranging step, the axis of the main body extends to each of a plurality of filling regions formed between the plurality of heat transfer fins between the outer peripheral surface of the main body and the inner peripheral surface of the outer cylinder. A mold member extending along the axial direction is disposed. In the shielding body forming step, a plurality of neutron shielding bodies in which hollow portions extending along the axial direction are formed are formed by filling each of the plurality of filling regions with a resin material.

According to such a method, the hollow part extended along an axial direction is formed in each neutron shield.
For this reason, when the neutron shield is thermally expanded, it is possible to efficiently secure a region of the hollow portion that becomes an expansion allowance of the neutron shield.
As a result, when the neutron shield is thermally expanded, it is possible to efficiently suppress the load on the main body, the heat transfer fin, and the outer cylinder.

(3) Moreover, at the said mold arrangement | positioning process, you may arrange | position the mold member in which the hollow part extended along the said axial direction was formed in each of these filling area | regions.

According to such a method, the mold member in which the hollow portion is formed is disposed in each of the plurality of filling regions, and the resin material is filled in each of the plurality of filling regions, thereby along the axial direction. A plurality of neutron shields in which extending hollow portions are formed can be formed.
Therefore, a hollow part can be formed inside each neutron shield without providing a step of removing the mold member.

(4) Further, in the mold arranging step, a soluble mold member may be arranged in each of the plurality of filling regions. In the shielding body forming step, after filling the resin material into each of the plurality of filling regions, the hollow portion may be formed by dissolving the mold member.

  According to such a method, the mold member can be easily removed, and a hollow portion can be formed inside each neutron shield.

(5) Moreover, in the said mold arrangement | positioning process, you may arrange | position the mold member containing a porous body in each of these filling area | regions.

According to such a method, it is possible to allow a large number of holes in the mold member to function as hollow portions only by disposing the mold member in each of the plurality of filling regions.
Therefore, a hollow part can be formed inside each neutron shield without providing a step of removing the mold member.

(6) Moreover, in the said mold arrangement | positioning process, you may arrange | position the said mold member of the state which covered the coating body on the outer surface in each of these filling area | regions. In the shielding body forming step, after filling each of the plurality of filling regions with a resin material, the hollow member may be formed by pulling out the mold member while leaving the covering body in each of the plurality of filling regions. Good.

According to such a method, a hollow part can be formed by easily pulling out the mold member from each of the plurality of filling regions.
Therefore, a hollow part can be formed inside each neutron shield by a simple method.

  According to the present invention, since the hollow portion is formed so as to extend along the axial direction inside each neutron shield, when each neutron shield is thermally expanded, a load is applied to the main body, the heat transfer fin, and the outer cylinder. Can be efficiently suppressed.

1 is a perspective view showing a spent nuclear fuel container according to a first embodiment of the present invention, which is a spent nuclear fuel container in a stored state. It is the perspective view which showed the state in which the container for spent nuclear fuel of FIG. 1 is conveyed. It is the plane sectional view which showed the container for spent nuclear fuel of FIG. It is the sectional side view which showed the container for used nuclear fuel of FIG. It is the plane sectional view which showed the main body of FIG. 4, a heat-transfer fin, an outer cylinder, and a neutron shield. It is a plane sectional view for demonstrating the manufacturing method of the container for used nuclear fuel of FIG. It is a plane sectional view for explaining a manufacturing method of a spent nuclear fuel container concerning a 2nd embodiment of the present invention. It is a plane sectional view for explaining a manufacturing method of a spent nuclear fuel container concerning a 3rd embodiment of the present invention. It is a plane sectional view for explaining a manufacturing method of a spent nuclear fuel container concerning a 4th embodiment of the present invention. It is a plane sectional view for explaining a manufacturing method of a spent nuclear fuel container concerning a 5th embodiment of the present invention. It is a plane sectional view for explaining a manufacturing method of a spent nuclear fuel container concerning a 6th embodiment of the present invention.

1. FIG. 1 is a perspective view showing a spent nuclear fuel container 1 according to a first embodiment of the present invention, which is a spent nuclear fuel container 1 in a stored state. In FIG. 1, a portion of the spent nuclear fuel container 1 is cut away.
The spent nuclear fuel container 1 is for containing spent nuclear fuel, and includes a main body 2, an outer cylinder 3, a shield 4, a basket 5, and a lid 6.

  The main body 2 is formed in a substantially cylindrical shape, and is made of, for example, low alloy steel or carbon steel. The main body 2 is closed at one end in the axial direction, and has an opening 2A at the other end in the axial direction.

The outer cylinder 3 is disposed outside the main body 2. The outer cylinder 3 is formed in the substantially cylindrical shape which shares an axis with the main body 2, for example, consists of carbon steel or stainless steel. That is, the outer cylinder 3 covers the main body 2 so as to face the outer peripheral surface of the main body 2 with a space therebetween.
The shield 4 is disposed between the main body 2 and the outer cylinder 3. As will be described later, the shield 4 is configured to shield radiation (neutrons).

The basket 5 is accommodated in the main body 2. The basket 5 is configured by stacking a plurality of thick plate-shaped blocks, and a plurality of storage chambers 5A are formed therein.
The lid body 6 is attached to the other end portion of the main body 2. The lid body 6 is formed in a disc shape and covers the opening 2A of the main body 2 so as to be sealed.

In the spent nuclear fuel container 1, spent nuclear fuel is accommodated in the accommodation chamber 5 </ b> A of the basket 5. The spent nuclear fuel container 1 is stored in a state in which the opening 2A of the main body 2 is sealed by the lid 6, the axis of the main body 2 is along the vertical direction, and the lid 6 is disposed above. Thus, the spent nuclear fuel container 1 accommodates the spent nuclear fuel in the main body 2 via the basket 5. Further, radiation (neutrons) emitted from the spent nuclear fuel stored in the main body 2 (basket 5) is shielded by the shield 4.
The used nuclear fuel container 1 is also used as a transport container for transporting used nuclear fuel.

FIG. 2 is a perspective view showing a state in which the spent nuclear fuel container 1 of FIG. 1 is transported. In FIG. 2, a part of the spent nuclear fuel container 1 is cut away.
When the spent nuclear fuel is transported, the buffer body 7 is attached to both ends of the main body 2 in the spent nuclear fuel container 1 in a state where the spent nuclear fuel is accommodated. The spent nuclear fuel container 1 is transported so that the axis of the main body 2 is kept in the horizontal direction. In addition, even if the spent nuclear fuel container 1 is dropped during transportation, the shock transmitted to the main body 2 is weakened by the buffer 7, so that the spent nuclear fuel container 1 can be transported safely.

2. Detailed Configuration of Shield and Member Surrounding Shield FIG. 3 is a plan sectional view showing the spent nuclear fuel container 1 of FIG.
In the following description, the spent nuclear fuel container 1 will be described with reference to a state where the container 1 is placed on a horizontal plane.
In the spent nuclear fuel container 1, a plurality of heat transfer fins 11 are arranged between the main body 2 and the outer cylinder 3.

  Each heat transfer fin 11 is formed in a plate shape extending in the vertical direction (the axial direction of the main body 2), and is made of a material having high thermal conductivity such as copper, for example. Each heat transfer fin 11 extends from the outer peripheral surface of the main body 2 toward the inner peripheral surface of the outer cylinder 3. That is, each heat transfer fin 11 extends in a direction orthogonal to the axial direction of the main body 2. More specifically, each heat transfer fin 11 extends in a direction inclined with respect to the radial direction of the main body 2. The plurality of heat transfer fins 11 are arranged at intervals in the circumferential direction of the main body 2.

  FIG. 4 is a side sectional view showing the spent nuclear fuel container 1 of FIG. As shown in FIG. 3 and FIG. 4, in the spent nuclear fuel container 1, a plurality of filling regions between the plurality of heat transfer fins 11 between the outer peripheral surface of the main body 2 and the inner peripheral surface of the outer cylinder 3. 12 is formed. Specifically, each filling region 12 is formed by the outer peripheral surface of the main body 2, the inner peripheral surface of the outer cylinder 3, and opposing surfaces of the adjacent heat transfer fins 11 that face each other. Each filling region 12 extends in the vertical direction.

  The shield 4 is composed of a plurality of neutron shields 41. Each neutron shield 41 is filled in each filling region 12. Each neutron shield 41 is made of a resin material that shields radiation such as neutrons. A hollow portion 42 is formed inside each neutron shield 41.

FIG. 5 is a plan sectional view showing the main body 2, the heat transfer fins 11, the outer cylinder 3, and the neutron shield 41 of FIG. 4. As shown in FIGS. 4 and 5, each hollow portion 42 has a long hole shape that extends in a direction perpendicular to the radial direction of the main body 2 when viewed in the vertical direction, and extends along the vertical direction. Yes. Each hollow portion 42 is disposed at the center of each neutron shield 41 when viewed in the vertical direction. The edge part of each hollow part 42 is arrange | positioned at intervals with the outer peripheral surface of the main body 2, the inner peripheral surface of the outer cylinder 3, and each heat-transfer fin 11. FIG. Each hollow portion 42 is arranged from the upper end portion to the lower end portion of each neutron shield 41.
In addition, each hollow part 42 should just be arrange | positioned inside each neutron shield 41. FIG. For example, each hollow part 42 may be arrange | positioned at the outer cylinder 3 side, and may be arrange | positioned at the main body 2 side.
Specifically, as shown in FIG. 5, in each hollow portion 42, the dimension L1 in the radial direction (width direction) of the main body 2 is, for example, not less than 0.5 cm and not more than 2.0 cm. In addition, each hollow portion 42 has a dimension L2 in a direction orthogonal to the radial direction of the main body 2, for example, 10 cm or more and 13 cm or less. Moreover, as shown in FIG. 4, each hollow part 42 has a vertical dimension L3 of, for example, not less than 400 cm and not more than 500 cm.

3. FIG. 6 is a cross-sectional plan view for explaining a method of manufacturing the spent nuclear fuel container 1 of FIG. In addition, in FIG. 6, the mold member mentioned later is shown schematically.

  When manufacturing the spent nuclear fuel container 1, first, a plurality of heat transfer fins 11 are attached to the outer peripheral surface of the main body 2 by welding. And the outer cylinder 3 is covered so that the outer side of the main body 2 from which the some heat-transfer fin 11 is extended toward the outward from the outer peripheral surface may be covered.

Next, the plurality of heat transfer fins 11 are attached to the inner peripheral surface of the outer cylinder 3 by welding. In this manner, a plurality of filling regions 12 are formed by the outer peripheral surface of the main body 2, the inner peripheral surface of the outer cylinder 3, and the plurality of heat transfer fins 11.
Thereafter, the mold member 13 is disposed in each filling region 12.
The mold member 13 is a long member made of a resin material. The mold member 13 includes a pair of split members 131.
Each divided member 131 is formed in a long plate shape. Each split member 131 is formed with a recess 131A.

  The recess 131 </ b> A is recessed inward from one surface of the dividing member 131. The recess 131A is formed from one end to the other end of the dividing member 131 in the longitudinal direction.

  And this pair of division member 131 is joined in the state where 131 A of recessed parts mutually opposes. Furthermore, one end part of a pair of recessed part 131A is obstruct | occluded with the resin material. In this way, the mold member 13 is formed. In the mold member 13, a region covered by the pair of recesses 131 </ b> A is formed as the hollow portion 42.

  Further, the mold member 13 is arranged in each filling region 12 so that the longitudinal direction thereof is along the axial direction of the main body 2. Each mold member 13 is held by a holding member (not shown) so as to maintain a fixed position in each filling region 12.

At this time, when viewed in the axial direction of the main body 2, each mold member 13 is disposed at the center of each filling region 12. In addition, the mold member 13 is disposed in each filling region 12, and in the axial direction of the main body 2, one end thereof is disposed at substantially the same position as the one end of the main body 2, and the other end is disposed in the main body 2. 2 is disposed at substantially the same position as the other end portion of 2.
Each mold member 13 only needs to be arranged inside each filling region 12. For example, each mold member 13 may be disposed on the outer cylinder 3 side or may be disposed on the main body 2 side.
Thereafter, the axis of the main body 2 is in a state along the vertical direction. At this time, the main body 2 is turned upside down with respect to FIG.
In this state, each filling region 12 is filled with a liquid resin material. The resin material filled in each filling region 12 is a resin material containing a lot of hydrogen atoms, and is a resin material such as an epoxy resin, for example.

Then, as the filled resin material is cured, the resin material and the mold member 13 are formed as each neutron shield 41 as shown in FIG. In this way, a plurality of neutron shields 41 in which hollow portions 42 extending in the axial direction of the main body 2 are formed are formed.
After that, the main body 2 is turned upside down to be in the state shown in FIG. 4, and the spent nuclear fuel container 1 is configured by appropriately attaching the members constituting the spent nuclear fuel container 1 described above.

As shown in FIG. 1, heat is generated in the spent nuclear fuel container 1 while the spent nuclear fuel container 1 manufactured in this way is stored. And as shown in FIG. 5, each neutron shield 41 is thermally expanded in each filling area | region 12 with the heat. At this time, each neutron shield 41 expands with each hollow portion 42 side as an expansion allowance.
In the above description, one mold member 13 extending in the axial direction of the main body 2 is arranged in each filling region 12. However, the mold member 13 is divided in advance in the axial direction of the main body 2, The divided members may be sequentially arranged in each filling region 12, and the mold member 13 may be configured in each filling region 12.

4). Effects (1) In the present embodiment, as shown in FIG. 4, the hollow portion 42 is formed inside each neutron shield 41. The hollow portion 42 extends in the axial direction of the main body 2.
Therefore, when each neutron shield 41 is thermally expanded, it is possible to efficiently secure a region of the hollow portion 42 that serves as an expansion allowance for each neutron shield 41.
As a result, when each neutron shield 41 is thermally expanded, it is possible to efficiently suppress the load on the main body 2, each heat transfer fin 11, and the outer cylinder 3.

(2) Moreover, in this embodiment, as shown in FIG. 6, the mold member 13 in which the hollow part 42 was formed is arrange | positioned in each filling area | region 12. As shown in FIG. In this state, the hollow portion 42 is disposed along the axial direction of the main body 2.

Therefore, by arranging the mold member 13 in each filling region 12 and filling each filling region 12 with a resin material, a plurality of neutron shields 41 having hollow portions 42 extending in the axial direction of the main body 2 are formed. it can.
As a result, the hollow portion 42 extending in the axial direction of the main body 2 can be formed inside each neutron shield 41 without providing a step of removing the mold member 13.

5. Second Embodiment Another embodiment of the present invention will be described with reference to FIGS. In the following description, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

In the first embodiment described above, the mold member 13 disposed in each filling region 12 includes a pair of split members 131. A recess 131 </ b> A is formed in each divided member 131.
On the other hand, in 2nd Embodiment, as shown in FIG. 7, in the mold member 14 arrange | positioned in each filling area | region 12, the recessed part 141A is formed only in the 1st mold member 141. FIG.
Specifically, in the second embodiment, a mold member 14 is disposed in each filling region 12 instead of the mold member 13.
The mold member 14 is a long member made of a resin material. The mold member 14 includes a first mold member 141 and a second mold member 142.

  The first mold member 141 is formed in a comb shape when viewed in the longitudinal direction. The first mold member 141 has a plurality of recesses 141A.

Each concave portion 141 </ b> A has a rectangular shape when viewed in the longitudinal direction, and is recessed inward from one surface of the first mold member 141. Each concave portion 141 </ b> A is formed from one end to the other end in the longitudinal direction of the first mold member 141. The plurality of recesses 141 </ b> A are arranged at intervals from each other in a direction orthogonal to the longitudinal direction.
The second mold member 142 is formed in a long plate shape.

The second mold member 142 is joined to the first mold member 141 so as to cover the plurality of concave portions 141A. Furthermore, the one end part of each recessed part 141A is obstruct | occluded with the resin material. In this way, the mold member 14 is formed. In the mold member 14, a plurality of concave portions 141 </ b> A covered with the second mold member 142 are formed as hollow portions.
At this time, each concave portion 141 </ b> A (hollow portion) extends in the axial direction of the main body 2. In addition, in the state where the hollow portion extends in the axial direction of the main body 2, each concave portion 141 </ b> A (hollow portion) continuously extends in the axial direction of the main body 2 and each concave portion 141 </ b> A (hollow portion) includes Both include a state where the main body 2 extends intermittently close to each other in the axial direction.

The mold member 14 is disposed in each filling region 12 such that the longitudinal direction thereof is along the axial direction of the main body 2.
Thereafter, each filling region 12 is filled with a liquid resin material.
According to this embodiment, the same effect as that of the first embodiment can be obtained.

Further, in this embodiment, as shown in FIG. 7, the mold member 14 is formed by joining the plate-shaped second mold member 142 to the first mold member 141 in which the plurality of concave portions 141A are formed. . In the mold member 14, a plurality of concave portions 141 </ b> A covered with the second mold member 142 are formed as hollow portions.
Therefore, in the mold member 14, a hollow portion composed of a plurality of regions can be easily formed.

6). Third Embodiment In the first embodiment described above, the mold member 13 disposed in each filling region 12 is made of a resin material and formed by joining a pair of divided members 131.
On the other hand, in 3rd Embodiment, as shown in FIG. 8, the mold member 15 which consists of metal materials is arrange | positioned in each filling area | region 12. As shown in FIG.
Specifically, in the third embodiment, a mold member 15 is disposed in each filling region 12 instead of the mold member 13.

The mold member 15 is a flat and long cylindrical member, and one end thereof is closed. The mold member 15 is made of a metal material, for example, a material having low rigidity such as aluminum. In the mold member 15, the internal space 15A is formed as a hollow portion.
The mold member 15 is disposed in each filling region 12 such that the longitudinal direction thereof is along the axial direction of the main body 2.
Thereafter, each filling region 12 is filled with a liquid resin material.
According to this embodiment, the same effect as that of the first embodiment can be obtained.
Further, in this embodiment, as shown in FIG. 8, a hollow portion is formed inside each filling region 12, and a mold member 15 made of a metal material is disposed.
Therefore, the simply formed mold member 15 can be disposed in each filling region 12.

7). Fourth Embodiment In the first embodiment described above, a mold member 13 having a hollow portion 42 formed therein is disposed in each filling region 12.
On the other hand, in 4th Embodiment, as shown in FIG. 9, the mold member 16 formed of a soluble material is arrange | positioned in each filling area | region 12. As shown in FIG.
Specifically, in the fourth embodiment, a mold member 16 is disposed in each filling region 12 instead of the mold member 13.
The mold member 16 is a long plate-shaped member. The mold member 16 is made of a soluble material, for example, a material that can be melted by heat, such as paraffin. However, the mold member 16 may be made of a material that can be melted by means other than heat, such as a solvent.
The mold member 16 is disposed in each filling region 12 such that the longitudinal direction thereof is along the axial direction of the main body 2.
Thereafter, each filling region 12 is filled with a liquid resin material in a state where the axis of the main body 2 is along the vertical direction.
After the resin material in each filling region 12 is cured, the mold member 16 is heated and melted. The melted mold member 16 is removed from the spent nuclear fuel container 1. At this time, the melted mold member 16 may be removed by turning the spent nuclear fuel container 1 upside down.
And in each neutron shield 41, the area | region where the mold member 16 was arrange | positioned is formed as a hollow part by removing the mold member 16. FIG.
According to this embodiment, the same effect as that of the first embodiment can be obtained.

In the present embodiment, as shown in FIG. 9, a mold member 16 made of a soluble material is disposed in each filling region 12. And after filling each filling area | region 12 with a resin material and hardening | curing the resin material, a hollow part is formed by melt | dissolving the mold member 16. FIG.
Therefore, the mold member 16 can be easily removed and a hollow portion can be formed inside each neutron shield 12.

8). Fifth Embodiment In the first embodiment described above, a mold member 13 having a hollow portion 42 formed therein is disposed in each filling region 12.
On the other hand, in the fifth embodiment, as shown in FIG. 10, a mold member 17 made of a porous body is disposed in each filling region 12.
Specifically, in the fifth embodiment, a mold member 17 is disposed in each filling region 12 instead of the mold member 13.

The mold member 17 is a long plate-shaped member. The mold member 17 is made of a porous body having a large number of holes, and is made of an elastic body such as silicon rubber sponge, for example. In the mold member 17, a large number of holes therein are formed as hollow portions.
The mold member 17 is disposed in each filling region 12 such that the longitudinal direction thereof is along the axial direction of the main body 2.
Thereafter, each filling region 12 is filled with a liquid resin material.

Then, heat is generated in the spent nuclear fuel container 1 and each neutron shield 41 is thermally expanded. At this time, each neutron shield 41 expands with the hollow portion (porous region) side as an expansion allowance, whereby the mold member 17 is elastically deformed.
According to this embodiment, the same effect as that of the first embodiment can be obtained.
Further, in this embodiment, as shown in FIG. 10, a mold member 17 made of a porous body is disposed in each filling region 12.
Therefore, only by disposing the mold member 17 in each filling region 12, a large number of holes in the mold member 17 can function as hollow portions.
Therefore, a hollow portion can be formed inside each neutron shield 41 without providing a step of removing the mold member 17.

9. Sixth Embodiment In the first embodiment described above, a mold member 13 having a hollow portion 42 formed therein is disposed in each filling region 12.
On the other hand, in the sixth embodiment, as shown in FIG. 11, a mold member 18 having no hollow portion formed therein is disposed in each filling region 12.
Specifically, in the sixth embodiment, a mold member 18 is disposed in each filling region 12 instead of the mold member 13.
The mold member 18 is a long plate-shaped member. The mold member 18 is covered with a covering 19 on its outer surface.

The covering 19 is formed in a thin film shape and is in close contact with the outer surface of the mold member 18. The covering 19 is made of, for example, a flexible material such as sponge or a soluble material.
Then, the mold member 18 covered with the covering body 19 is disposed in each filling region 12.
Thereafter, each filling region 12 is filled with a liquid resin material.

  After the resin material in each filling region 12 is cured, the covering 19 is left in each filling region 12 and the mold member 18 is pulled out. And the area | region where the mold member 18 was arrange | positioned is formed as a hollow part.

Then, heat is generated in the spent nuclear fuel container 1 and each neutron shield 41 is thermally expanded. At this time, each neutron shield 41 expands with the hollow portion side as an expansion allowance, so that the covering 19 is deformed.
According to this embodiment, the same effect as that of the first embodiment can be obtained.

In the present embodiment, as shown in FIG. 11, the mold member 18 covered with the covering body 19 is disposed in each filling region 12. When the resin material is filled in each filling region 12 and the resin material is cured, the covering member 19 is left in each filling region 12 and the mold member 18 is pulled out. And the area | region where the mold member 18 was arrange | positioned is formed as a hollow part.
Therefore, the covering body 19 can be easily pulled out from each filling region 12 to form a hollow portion.
As a result, a hollow portion can be formed inside each neutron shield 41 by a simple method.

DESCRIPTION OF SYMBOLS 1 Used nuclear fuel container 2 Main body 3 Outer cylinder 11 Heat transfer fin 12 Filling area 13-18 Mold member 19 Covering body 41 Neutron shielding body 42 Hollow part

Claims (6)

A cylindrical body capable of containing spent nuclear fuel inside;
An outer cylinder that covers the main body so as to face the outer peripheral surface of the main body with a space therebetween;
A plurality of heat transfer fins extending from the outer peripheral surface of the main body toward the inner peripheral surface of the outer cylinder;
A plurality of neutron shields disposed between the plurality of heat transfer fins and having hollow portions formed therein,
The said hollow part is a spent nuclear fuel container characterized by extending along the axial direction where the axis of the said main body extends in each of these neutron shields. An outer cylinder installation step of covering an outer cylinder so as to cover an outer side of a cylindrical main body in which a spent nuclear fuel can be accommodated and a plurality of heat transfer fins extend outward from an outer peripheral surface; ,
Between the outer peripheral surface of the main body and the inner peripheral surface of the outer cylinder, each of a plurality of filling regions formed between the plurality of heat transfer fins extends along an axial direction in which the axis of the main body extends. A mold placement process for placing mold members;
A shielding body forming step of forming a plurality of neutron shielding bodies in which hollow portions extending along the axial direction are formed by filling a resin material into each of the plurality of filling regions. A method for producing a spent nuclear fuel container.   3. The spent nuclear fuel according to claim 2, wherein in the mold arranging step, a mold member in which a hollow portion extending along the axial direction is formed is arranged in each of the plurality of filling regions. Container manufacturing method. In the mold arrangement step, a soluble mold member is arranged in each of the plurality of filling regions,
3. The spent nuclear fuel according to claim 2, wherein in the shielding body forming step, a hollow portion is formed by melting the mold member after filling each of the plurality of filling regions with a resin material. Container manufacturing method.   3. The method for producing a spent nuclear fuel container according to claim 2, wherein in the mold arranging step, a mold member including a porous body is arranged in each of the plurality of filling regions. In the mold arranging step, the mold member in a state where a covering is covered on the outer surface of each of the plurality of filling regions is arranged,
In the shielding body forming step, after filling the resin material in each of the plurality of filling regions, the hollow member is formed by pulling out the mold member while leaving the covering body in each of the plurality of filling regions. The method for producing a spent nuclear fuel container according to claim 2, wherein:

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