JP3441248B2 - Cask storage - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cask storage box for storing casks containing spent fuel generated in a nuclear power plant.

[0002]

2. Description of the Related Art Spent fuel generated as a result of operating a nuclear reactor at a nuclear power plant is taken out of the nuclear reactor and immediately stored in a fuel storage pool installed in the reactor building.

After the decay heat generated from the spent fuel is cooled with pool water during this temporary storage, it is stored in a cask of a container for separately storing it in small amounts, and the cask storage in a separate building is used for reprocessing facilities. Store until delivered. Figure 11
As shown in the side sectional view of FIG. 1, the cask storage 1 comprises a surrounding building wall 2, an upper shed 3 and a foundation 4, and further,
On the foundation 4, a cask base 6 for storing a large number of casks 5 upright independently is provided over a plurality of rows.

An overhead crane 8 is movably mounted on the runway 7 constructed above the building wall 2. The cask 5 containing the spent fuel is trailer 9 from the reactor building of the nuclear power plant in the cask storage 1.
When it is carried in, the overhead crane 8
It is hung up by, and carried to the cask stand 6 and stored.

At this time, the cask 5 has a trailer 9
However, it is carried in the horizontal position, but when it is lifted by the overhead crane 8 in the cask storage 1, it is placed in the vertical position. Normally, the central passage or the cask 5 on the cask base 6 is used in the back space to store it in the back position. It is stored in order from the front to the front. In addition, when carrying out the products, since they are sequentially taken out from the front side, they are first in and last out.

[0006]

The radiation leaking from a large number of casks 5 stored in the cask storage cabinet 1 is completely shielded by the building wall 2 and the shed 3 of the cask storage cabinet 1. For this reason, since it is particularly necessary to thicken the concrete of the shed 3, the weight of the shed 3 becomes large and in order to maintain the strength, not only the shed 3, but also the building wall 2 and the foundation 4
There was an obstacle to the large-scale building structure.

Further, when the weight of the shed 3 is large, the center of gravity of the building becomes high, and the seismic resistance tends to deteriorate. In order to install the overhead crane 8 above the cask storage 1, the overhead crane 8 runs. In order to support the runway 7, the building wall 2 is made thick, and the height is high, so that the construction structure is large-scale and many materials are required.

Further, the heat generated from the cask 5 during storage can be cooled by replacing the air in the cask storage 1 with the outside air. At this time, the radiation leaked from the cask 5 is transferred to the outside of the cask storage 1. It was necessary to install an intake and exhaust mechanism that would not leak.

An object of the present invention is to install a radiation shielding hatch for each cask to be stored in the cask storage, to shield radiation and to promote cooling by natural convection to reduce the weight of the shed. It is to provide a cask storage that is possible.

[0010]

In order to achieve the above-mentioned object, a cask storage according to the invention of claim 1 is a building wall constructed around the building wall, a roof covering the building wall, and a plurality of casks inside. And a cask storage room provided with a plurality of rows of cask mounts to store them upright, and an inner wall surrounding the cask storage room is provided to form a building ventilation passage and the inner wall and the building wall A ventilation hole that opens in a maze position, a hatch that is detachably installed on the top of the cask stored in the cask stand to allow ventilation, and that shields radiation from the cask, and is supported by the building wall and the inner wall.
Is lifting consists of a traveling freely gantry crane between the cask vault and adjacent cask transport room, the C
The base has an opening in the center and the opening of this base
Fit the support leg that has an open perimeter and the top of this support leg.
It is characterized by being assembled with a hatch lid which is worn to shield radiation .

A large number of casks stored in the cask storage chamber by a crane are covered with a hatch for each cask to shield the radiation leaking from the cask, and to cool the cask by natural convection. It does not interfere with distribution. The hatches are structural parts to be formed
Since the weight of the dispersion, hand upon storage of the cask, carry-out
Installed by assembling the hatch when entering and disassembling
The handling work for removal becomes easier .

In addition, the cask is cooled by introducing the outside air to the lower part of the cask through a building ventilation passage consisting of a building wall and an inner wall forming a maze against radiation, cooling the cask and storing it from the hatch. Although it flows into the room, after that, it is discharged to the outside from the exhaust port provided in the upper part of the shed.

Furthermore, the portal crane is designed to have a long leg.
Lowering the height of building walls that are more runways
And the portal crane and the lifted
Since the weight of the disc is distributed between the building wall and the inner wall,
Also, the thickness of the inner wall can be reduced .

In the cask storage according to the second aspect of the present invention, a hatch is installed for each cask. As a result, it is possible to easily manage the radiation shielding and heat radiation for each stored cask, and to reduce the exposure in the cask storage.

According to the third aspect of the present invention, the cask storage cabinet is installed on a support column provided with a hatch in which the hatch is planted in the cask storage chamber and the inner wall. This allows
Since the weight of the hatch is dispersed and supported by the support column and the inner wall via the support member, the thickness of the inner wall and the building wall can be reduced.

According to the fourth aspect of the present invention, the cask storage cabinet is installed on a support column provided with a hatch in the cask storage chamber and a support column installed in the cask storage chamber. As a result, the weight of the hatch is dispersed and supported by the support pillars and the building wall via the supporting member, so that the thickness of the building wall can be reduced.

In the cask storage according to the fifth aspect of the present invention, a step is provided at the fitting portion of the hatch with the support member. Thereby, when the hatch is installed on the support member,
The positioning is easy, and the gap with the support member is not opened, and the radiation shielding effect is high.

In the cask storage according to the sixth aspect of the present invention, the position guide is projected on the support member for installing the hatch. The hatch that is hung by the crane can be easily positioned by installing it on the support member along the position guide.

In the cask storage according to the invention of claim 7, the shed in the cask storage in which the gate crane is installed is a lightweight shed without radiation shielding ability. Radiation leaking from the cask stored in the cask storage is blocked by a hatch. Furthermore, in the case of a gate-type crane, the position of the runway can be lowered, so there is no need to burden the roof with radiation shielding capability and load, so a lightweight roof can be created, and the burden on the building walls that support this can be reduced. To be done.

In the cask storage according to the invention of claim 8 , an exhaust port is provided in the roof of the cask storage. The cask stored in the cask storage is cooled by the introduced outside air, and the air whose temperature has risen rises. This rising air is discharged to the outside from the exhaust port provided in the roof, and natural convection occurs.

In the cask storage according to the invention of claim 9 , the child roof is installed on the uppermost part of the shed and an exhaust port is provided by a gallery. As a result, the air whose temperature has risen due to cooling of the cask ascends and reaches the small roof at the top of the shed, and is discharged from the galleries. Since the wind blows less wind and rain from the outside and the exhaust gas is promoted by the wind, this exhaust effect increases the amount of outside air introduced into the cask storage cabinet, thereby improving the cooling effect of the cask storage cabinet.

In the cask storage according to the invention of claim 10 , the hatch is a multiple hatch in which a plurality of support legs and a hatch lid are installed on one base. This multiple hatch improves the efficiency of storage work because the lids and the opening are performed collectively for a plurality of casks.

In the cask storage according to the eleventh aspect of the present invention, a hatch and a multiple hatch are integrally formed with a base having a central opening, a support leg having a peripheral opening, and a hatch lid. This reduces the man-hours for installing and removing the hatch on the cask, and enables quick work.

In the cask storage according to the invention of claim 12, the support member for installing the hatch is supported by the inner wall surrounding the cask storage chamber. The inside of the cask storage can be widely used, and it becomes easy to secure a transportation path for the cask.

According to the thirteenth aspect of the present invention, in the cask storage cabinet, the support member for installing the hatch is supported by the inner wall surrounding the cask storage chamber and the support wall planted in the cask storage chamber. Since the weight of the hatch is distributed to the inner wall and the support wall via the support member, the burden on the support member, the inner wall and the support wall is reduced.

In the cask storage according to the invention of claim 14 , the hatch is supported by an inner wall surrounding the cask storage chamber and a support wall planted in the cask storage chamber. Since the hatch is directly installed on the inner wall and the support wall without using the support member, the configuration is simplified and the support member can be reduced.
It is especially effective for applying multiple hatches.

The cask storage according to the invention of claim 15 does not have a shed covering the upper part of the cask storage. Since there is no roof in the cask storage, cooling of the cask is good, and the burden on the building walls and foundations that support the roof is reduced, which reduces the construction man-hours and the amount of materials.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. It should be noted that the same reference numerals are given to the same constituent parts as those in the conventional art, and detailed description thereof will be omitted. The first embodiment relates to claims 1 to 8. As shown in the side sectional view of FIG. 1 and the internal plan view of FIG. 2, a cask storage box 11 has a building wall 12 built around it and The upper part is covered with a lightweight shed 13 having no radiation shielding ability, and inside is provided a cask storage room 14 having a plurality of rows of cask mounts 6 for storing a plurality of casks 5 standing upright on a foundation 4.

In the cask storage room 14, a building wall 12 and an inner wall 15 are formed to form a building ventilation passage 16 for ventilation with an opening at a key point, and the building ventilation passage 16 is a gate-type on the top as a runway. It is equipped with a crane 17. Further, a cask loading / unloading chamber 19 provided with an inspection table 18 adjacent to the cask frame 6
Is provided.

In the cask storage chamber 14, a support column 20 is planted between the inner walls 15, and a support member 21 is provided so as to partition the cask 5 supported by the cask 5 and stored in the cask base 6 at the upper part. Install side by side. The support member 21 is
It can also be supported by the building wall 12 and support columns 20.

Above this is the hatch shown in the enlarged plan view of FIG.
22 is detachably installed and each of the stored casks 5 is covered. A cross-shaped position guide 23 is provided on the upper surface of the support member 21 so as to project from the hatch.
The positioning of 22 on the support member 21 is facilitated.

As shown in the vertical sectional view of FIG. 4, the hatch 22 is a base 24 having a rectangular periphery and a circular hole at the center.
A plurality of vertical plates are attached to the periphery of the base opening 24a, the upper and lower sides of which are annular, and the supporting legs 25 are provided with openings between them. Further, by fitting on the support leg 25 to cover the base opening 24a and the leg opening 25a of the support leg 25,
It consists of a disk-shaped hatch lid 26 of sufficient thickness and diameter to shield the radiation leaking from the cask 5 located below 24.

It is to be noted that an opening step 24b for facilitating fitting with the support leg 25 is provided at an upper end of the base opening 24a, and a fitting with the supporting member 21 is facilitated around a lower end of the base 24. It forms a base step 24c. The support leg 25,
The upper and lower annular members are formed by welding a plurality of vertical plate members in the middle thereof, and the upper and lower annular members are fitted to the stepped portion 26a of the hatch lid 26 and the stepped portion 24b of the base opening 24a of the base 24, respectively. To meet.

The leg openings 24a are formed between the plurality of vertical plate members of the support leg 24, and together with the base 24, the base opening 23a, and the hatch lid 26 form a radiation maze, which cools the cask 5. It also serves as a ventilation passage for cooling air.

As shown in the front sectional view of FIG. 5, the building wall is
In a building ventilation passage 16 formed between the inner wall 15 and the inner wall 15, an intake port 12a for introducing outside air is provided in the building wall 12, and this intake port 12
A ventilation port 15a is provided in the inner wall 15 at a position where it becomes a maze with a. Furthermore, an exhaust port 13 is provided on the upper side surface of the lightweight shed 13.
a is provided.

Next, the operation of the above configuration will be described. A cask 5 loaded by a trailer 9 from a reactor building (not shown) into the cask loading / unloading chamber 19 of the cask storage 11.
Is taken down from the trailer 9 to the inspection table 18, stands upright for inspection, and is then suspended by the portal crane 17 using the suspenders 10.

The gate crane 17 is a conventional overhead crane 8
When the number of stored casks 5 is small, the space on the cask base 6 where the cask 5 is not stored is used as a transportation path, and the cask 5 is located in front of the cask base 6 in the back in order. Carry it in.

In the gate type crane 17, since the hoisting height can be easily obtained due to the design of the leg length, a large number of casks 5 are stored in the cask storage room 14, and the cask base 6 on the cask base 6 is stored. If there is no space and a transportation route cannot be secured, or if the cask 5 farther from the cask carry-in / out chamber 19 is carried out, carry the cask 5 over the other hatch 22 to the cask carry-in / out chamber 19. You can That is, the cask 5 can be carried in and out regardless of the storage position.

After storing the cask 5, the portal crane 17 mounts the base 24 on the supporting member 21 above the cask 5 with the position guide 23 as a guide. Further, the support leg 25 and the hatch cover 26 are carried in this order and stacked on top of each other, and the hatch 22 formed thereby covers the cask 5 so as not to prevent ventilation for cooling the cask 5 from above the cask 5. The radiation that leaks into it is blocked.

At this time, with a base step provided on the base 24
24c supports the support member 21, and 24b with stepped openings supports the legs.
By assembling the hatch 22 with the lower part of 25 and by fitting the stepped portion 26a of the hatch cover 26 on the upper part of the support leg 25, the hatch 22 can be assembled and installed on the support member 21 with certainty.

The hatch 22 includes the base 24 and the support leg 2
Since the 5 and the hatch lid 26 are manufactured separately, the weight of each structural portion is small and the handling is easy. In the following, a large number of casks 5 are carried into the cask storage chamber 14 and stored by installing a hatch 22 on the upper portion and covering the hatches.

Radiation leaking from the periphery of each cask 5 is shielded by the adjacent cask 5 in the cask 5 in the cask storage chamber 14 after a part of the cask 5 is carried in and after all the casks have been carried in, and the inner wall at the outermost peripheral part. 15 and building wall 1
2, shielded by inner wall 15 or building wall 12.

The upper portion is shielded by the base 24 and the hatch lid 26 which form the hatch 22. Shielding by the hatch 22, for storing the cask 5 units, because it is carried out, all of the cask 5 and stored in the cask storage chamber 14, by a lid with the hatch 22, the radiation leaks into the cask depot 11 There is no such thing.

Regarding the dissipation of the heat generated from the cask 5 stored in the cask storage 11, the outside air having a low temperature is supplied from the intake port 12a formed in the building wall 12 of the cask storage 11 to the building ventilation passage 16 The outside air is introduced into the cask storage chamber 14 from the ventilation port 15a formed in the inner wall 15 at a position that is a labyrinth of radiation away from the intake port 12a of the building ventilation channel 16.

The outside air flowing into the cask storage room 14 is
Ascending from the bottom of the cask 5 along the outer circumference in the space between the casks 5 takes heat from the cask 5 and warms it up.
Hatch 22 forming a radiation maze for natural convection
The base opening 24a, the leg openings 25a, and the hatch cover 26 pass under and flow upward.

The air whose temperature has risen is stored in the cask storage cabinet.
Gathered at the upper part of 11 and discharged to the outside through the exhaust port 13a of the lightweight shed 13. As a result, a negative pressure is generated around the cask 5, and cold outside air flows into the cask storage chamber 14 via the building ventilation passage 16 to cool the cask 5.

According to the first embodiment, the load of the gate-type crane 17 suspending the cask 5 is supported by both the building wall 12 and the inner wall 15 of the cask storage case 11 in comparison with the conventional one.
Both the building wall 12 and the inner wall 15 can be made thin. Further, since the gate type crane 17 has long legs, it is not necessary to increase the height of the building wall 12, and in order to shield the radiation from the cask 5 together with the inner wall 15, the height of the cask 5 is almost the same. Is enough.

Further, since the roof of the cask storage 11 does not need the function of shielding radiation, various facilities and equipment such as the cask 5 and the gate crane 17 are protected from wind and snow and the ventilation conditions are maintained. Since it is sufficient to construct the lightweight shed 13 for the construction, the scale of the shed becomes simple. Therefore, since the weight of the lightweight roof 13 is reduced, the thickness of the building wall 12 supporting the weight can be further reduced, so that both the number of construction steps and the amount of materials can be reduced.

The second embodiment relates to claim 11 , wherein the hatch 22 is prefabricated in advance with the base 24 and the support legs 25,
The hatch lid 26 is integrally formed by welding or the like. As a result, the unit weight of the hatch 22 is increased, but since the hatch 22 can be quickly attached and detached when the cask 5 is stored, this workability is improved and the radiation dose leaking upward from the cask 5 is improved. It can be reduced.

The third embodiment relates to claim 10 , and FIG.
As shown in the enlarged plan view of FIG. 2, the multiple hatch 27 covers two or several casks 5 together, and here, the two hatches will be described as an example. In the multiple hatch 27, two multiple base openings 28a are opened in one multiple base 28, and two sets of the support leg 25 and the hatch cover 26 are provided for the base opening 28a.
Is installed and configured.

Further, the position guide 23 having the same structure as that of the above-mentioned first embodiment is installed on the upper surface of the multiple base 28 so as to project, and an opening step 28b (not shown) is provided at the upper end of the base opening 28a and the lower end periphery. By providing the base stepped portion 28c, the same operation and effect as in the first embodiment can be obtained in this multiple hatch 27 as well. In addition, this multiple hatch
In 27, as in the first embodiment, the work efficiency can be increased by preliminarily fixing the two sets of the support legs 25 and the hatch cover 26 to the multiple base 28 by welding or the like.

The fourth embodiment relates to claim 12 , and FIG.
As shown in the enlarged plan view of FIG. 1, the cask storage 29 has a support member 21 for installing a hatch 22 that covers the upper portion of the cask 5.
Building ventilation passage 16 with the building wall 12 provided in the cask storage room 14
It is configured to be supported by the inner wall 15 forming the. As a result, it is not necessary to plant the support columns 20 in the cask storage room 14, so the number of construction steps and the amount of materials can be reduced. In addition,
The other structure is the same as that shown in the first embodiment, and therefore the same operation and effect can be obtained .

The fifth embodiment relates to claim 13 , and FIG.
As shown in the enlarged plan view of FIG. 1, the cask storage 30 has a support wall 31 planted in the center of the cask storage chamber 14, and an inner wall forming a building ventilation passage 16 with the support wall 31 and the building wall 12.
The support member 21 for mounting the hatch 22 for covering the upper portion of the cask 5 is supported by the member 15.

According to this structure, since the support member 21 having the hatch 22 is supported by the support wall 31 which is continuous in the center, it is easy to secure the strength. Further, the support wall 31 shields radiation leaking from the cask 5. The rest of the configuration and action are similar to those of the first embodiment, and the same action and effect can be obtained.

The sixth embodiment relates to claim 14 , and FIG.
As shown in the enlarged plan view of FIG. 3, the cask storage 32 has a support wall 31 which is divided into the center of the cask storage chamber 14 and the four casks 5 without partitioning the support member 21. In addition, the multiple hatch 27 is installed on the support wall 31 and the inner wall 15. The function of this configuration is that the support member
Since 21 is not used, the structure is simplified and can be used for a single-unit hatch 22, but it is particularly effective when a multiple hatch 27 having a large base 28 is applied.

The seventh embodiment relates to claim 9 , and FIG.
As shown in the vertical cross-sectional view, the roof of the lightweight shed 34 in the cask storage 33 is a double-flow roof 36 with a small roof 35, and the small roof 35 is provided with a gallery 37 as an exhaust port. The operation of the above configuration has a drawback that the double roof 36 has a height higher than that of a flat roof having a horizontal upper portion.

[0057] However, good stream of rain and snow, the cask 5 is cooled by the cask depot 33, the air temperature becomes high rises by natural convection,
Since it reaches the top of both floating roofs 36 and is further discharged from the gallery 37 of the small roof 35, the air having a high temperature does not stay in the cask storage box 33, and the exhaust effect is high.

The eighth embodiment relates to claim 15, and although not shown, the cask 5, the hatch 22 for covering the cask 5, and various equipments such as the gate crane 17 are outdoor type so that a cask storage is provided. A structure without a roof is also acceptable. As a function and an effect of this, although various equipments such as the cask 5 are contaminated by dust, heat dissipation becomes good, construction of a roof is unnecessary, and construction man-hours and material amount are reduced.

Although the above embodiment has been described by using the gate crane 17 for transporting the cask 5, even if an overhead crane is used as in the conventional case, except for the effect on the building wall 12, There is no hindrance to the transportation of the cask 5.

[0060]

As described above, according to the present invention, since the radiation shielding of the stored cask is individually controlled, the inside of the cask storage can be cooled and the required roof can be constructed with a reduced weight, so that the center of gravity of the building is reduced. It becomes lower and the earthquake resistance is improved. In addition, the weight of the shed is significantly reduced, which has the effect of significantly reducing the construction man-hours and the amount of materials.

[Brief description of drawings]

FIG. 1 is a side sectional view of a cask storage case according to a first embodiment of the present invention.

FIG. 2 is a plan view of the inside of the cask storage cabinet according to the first embodiment of the present invention.

FIG. 3 is a front sectional view of the cask storage according to the first embodiment of the present invention.

FIG. 4 is an enlarged plan view of a hatch portion according to the first embodiment of the present invention.

FIG. 5 is a vertical cross-sectional view of a hatch portion of an embodiment according to the present invention.

FIG. 6 is an enlarged plan view of a hatch portion according to a third embodiment of the present invention.

FIG. 7 is a plan view of the inside of a cask storage cabinet according to the fourth embodiment of the present invention.

FIG. 8 is a plan view of the inside of a cask storage cabinet according to the fifth embodiment of the present invention.

FIG. 9 is a plan view of the inside of the cask storage cabinet according to the sixth embodiment of the present invention.

FIG. 10 is a vertical sectional view of a cask storage shed roof according to a seventh embodiment of the present invention.

FIG. 11 is a side sectional view of a conventional cask storage.

[Explanation of symbols]

1,11,29,30,32,33 ... Cask storage, 2,12 ... Building wall, 3 ... Shelf, 4 ... Foundation, 5 ... Cask, 6 ... Cask mount, 7 ... Runway, 8 ... Overhead crane, 9 ... Trailer, 10 ... Lifting equipment, 12a ... Intake port, 13, 34 ... Lightweight shed,
13a ... Exhaust port, 14 ... Cask storage room, 15 ... Inner wall, 15a ...
Ventilation port, 16 ... Building ventilation passage, 17 ... Gate crane, 18 ... Inspection table, 19 ... Cask loading / unloading room, 20 ... Support pillar, 21 ... Support member, 22 ... Hatch, 23 ... Position guide, 24 ... Base, 24a ，
28a ... Base opening, 24b ... Opening step, 24c ... Base stepping, 25 ... Support leg, 25a ... Leg opening, 26 ... Hatch lid, 26a
… With a lid, 27… Multiple hatches, 28… Multiple bases, 31… Support walls, 35… Small roofs, 36… Double roofs, 37… Gallery.

Front Page Continuation (72) Inventor Akira Asano 8 Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa Toshiba Corporation Yokohama Works (56) Reference JP-A-61-158570 (JP, A) JP-A-63-30791 (JP-A-63-30791) JP, A) JP 58-131595 (JP, A) JP 61-126499 (JP, A) Fukukaihei 4-126199 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G21C 19/06 G21F 7/005 G21F 7/015 G21F 9/36 531

Claims (15)

(57) [Claims] 1. A cask storage room provided with a building wall built around it, a shed covering the building wall, a cask storage room in which a plurality of rows of cask stands for vertically storing a plurality of casks are installed, and a cask storage room. An inner wall that surrounds the building is provided to form a building ventilation path with the building wall, and the inner wall and the building wall can be attached to and detached from the vents that are opened at positions where they become mazes with each other and the upper portion of the cask stored on the cask base. a hatch for shielding radiation from ventilation is possible cask installed in the
Building block is supported by the wall and the inner wall consists of a traveling freely gantry crane <br/> over down between the cask vault and adjacent cask transport room, it said hatch based center is opened
And a support leg with an open perimeter that fits into the opening in this base
And a hatch that fits over this support leg to block radiation
A cask storage cabinet characterized by being assembled with a lid . 2. The cask storage cabinet according to claim 1, wherein the hatch is installed for each cask. 3. The cask storage as claimed in claim 1, wherein the hatch is installed on a support column which is planted in a cask storage chamber and a support member which is arranged on the inner wall. 4. The cask storage cabinet according to claim 1, wherein the hatch is installed on a support column which is planted in a cask storage chamber and a support member which is arranged on the building wall. 5. The cask storage box according to claim 1, wherein the hatch is provided with a step at a fitting portion with a support member on which the hatch is installed. 6. The cask storage according to claim 1, wherein the support member is provided with a position guide of a hatch installed on the upper surface. 7. The cask storage according to claim 1, wherein the storage of the cask storage in which the gate-type crane is installed is a lightweight roof without radiation shielding ability. 8. The cask storage according to claim 1, wherein an exhaust port is provided in a roof of the cask storage. 9. The cask storage box according to claim 1, wherein a child roof is installed at the uppermost part of the shed and an exhaust port is provided by a gallery. 10. The cask storage according to claim 1, wherein the hatch is a multiple hatch in which a plurality of support legs and a hatch lid are installed on one base. 11. The hatch and the multiple hatch according to claim 1, wherein a base having an opening in the center, a support leg having an opening in the periphery, and a hatch lid are integrated with each other. Cask storage. 12. The cask storage cabinet according to claim 1, wherein a support member for installing the hatch is supported by an inner wall surrounding the cask storage chamber. 13. The cask storage cabinet according to claim 1, wherein the support member for installing the hatch is supported by an inner wall surrounding the cask storage chamber and a support wall planted in the cask storage chamber. 14. The cask storage cabinet according to claim 1, wherein the hatch is supported by an inner wall surrounding the cask storage chamber and a support wall embedded in the cask storage chamber. 15. The cask storage according to claim 1, wherein the cask storage is not provided with a roof covering an upper portion.