JP2004219151A - Spent fuel storage facility and its maintenance method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce worker's dose in maintenance of a spent fuel storage facility. <P>SOLUTION: The spent fuel storage facility has a storage room 2 storing in the air, a plurality of canisters 1 containing spent nuclear fuel and surrounded by walls having radiation shield function, an intake tunnel 8 for taking air in the storage room, an exhaust tunnel 9 for exhausting air in the storage room, and a canister carriage room 3 arranged adjacent to the storage room and letting the canister pass for carrying a plurality of canisters to a specific location in the storage room. The storage room is partitioned into a plurality of cells 35a, 35b and 35c by partitioning walls 15 having radiation shield function, and each of cells is connected with both the intake tunnel and the exhaust tunnel. A maintenance method for the spent fuel storage facility has a moving process for moving the canister in a part of a plurality of cells to other cell. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention takes out a canister (storage container) containing spent fuel from a transport cask in a storage facility of spent nuclear fuel (hereinafter, also simply referred to as “spent fuel”) taken out of a nuclear power generation facility, The present invention relates to a (vault-type) dry fuel storage facility for storing this in the air in a room surrounded by concrete or the like in a building.
[0002]
[Prior art]
A conventional vault storage type intermediate storage facility will be described with reference to FIGS. A conventional vault storage type intermediate storage facility includes a storage room 2 in which a plurality of canisters 1 each of which contains used fuel are stored side by side, and an upper portion thereof for transporting the canisters 1 to a predetermined position in the storage room 2. The transfer chamber 3 is provided, and has a room configuration vertically divided by a transfer chamber floor (storage room ceiling) 33. The storage room 2 is designed to minimize the size of the building as one space in which the canisters 1 are densely arranged in a lattice or staggered manner. The entire intermediate storage facility has a semi-underground structure so that the storage room 2 is located below the ground 31.
[0003]
The canister 1 may be stored in a storage tube and stored, or may be directly installed on a canister foundation 5 on the floor of the storage room 2. In the example of FIG. 14 (a), as shown in FIG. 14 (b), a method of installing a steel pipe 6 around the canister 1 for heat removal and installing it directly on the foundation 5 on the floor of the storage room 2 Is shown.
[0004]
As another example, as shown in FIG. 14 (c), there is a structure in which the upper end of a storage pipe 4 in which a canister 1 is stored is supported from the ceiling of the storage room 2 and the lower end is swung by the two floors of the storage room.
[0005]
In order to cool the generated heat from the spent fuel, the storage chamber 2 is supplied with air from one wall, and a cooling air path having an opening communicating with the outside is provided to exhaust air from the other wall. Is configured to cool the canister 1 by natural circulation.
[0006]
That is, the air taken in from the air supply opening 7 opened to the outside of the building is guided to the storage room 2 through the air supply passage 8 from the storage room entrance 50 at the lower part of the storage room 2, and cools the heat generated from the canister 1. I do. The warmed air having a reduced density is guided from the storage room outlet 52 at the upper part of the storage room 2 to the exhaust air passage 9, rises in the exhaust air passage 9, and is discharged from the exhaust port 10 to the outside of the building. The exhaust port 10 is located higher than the intake port 7. This produces a natural circulation force (chimney effect) based on the difference in air density. Due to this chimney effect, the inside of the storage room 2 is supplied with natural air by natural ventilation, so that the cooling air is secured.
[0007]
Here, in the storage tube method, heat generated from the canister 1 is cooled by an air flow through the storage tube 4. Although there is a method of performing forced ventilation using a fan or the like, natural ventilation that can be performed without requiring external power is preferable from the viewpoint of safety, reduction of maintenance work, and economy.
[0008]
Further, radiation such as neutrons and gamma rays emitted from the spent fuel sealed inside the canister 1 in the storage room 2 is shielded around the storage room 2 or the transfer room 3 above the storage room 2 and around the site. Therefore, the wall of the storage room 2 and the ceiling 33 are surrounded by a frame having a shielding performance. An opening 18 having a hatch cover 11 having shielding performance is installed at a position directly above each canister 1 for loading and unloading the canister 1 from the storage room ceiling 33, and the hatch cover 11 is opened when the canister 1 is loaded and unloaded. I do.
[0009]
Further, in order to shield radiation from the storage room 2 to the outside through the supply air passage 8 and the exhaust air passage 9, a plurality of shielding floors 12 are alternately arranged in a labyrinth manner in the middle of each air passage. There is a method.
[0010]
As described above, the canister transfer chamber floor (storage room ceiling) 33 is provided with openings 18 by the number of canisters 1 that can be stored, and the transfer chamber floor 33 is provided with a considerable amount of openings 18. become. In addition, since the peripheral wall of the storage room 2 supports the transfer room floor 33, the support span of the transfer room floor 33 is generally long. For this reason, the transfer chamber floor 33 is structurally severe against a large overload, and the transfer device is provided with a large crane 13 or the like over the entire storage portion of the canister 1 by setting a large crane 13 or the like in the main direction (FIG. The canister 1 is moved to a predetermined storage position by a trolley 14 or the like that moves on a gutter of a crane 13 in a direction perpendicular to this direction.
[0011]
Further, in order to shield the radiation from the canister 1 being transported in the transport chamber 3, the canister 1 is housed and moved in the shield, and the hatch cover 11 is covered by covering the opening 18 with the shield at the storage position of the canister 1. After opening, the canister 1 is lowered into the storage room 2 for storage, and the hatch cover 11 is closed to complete the transfer.
[0012]
[Problems to be solved by the invention]
The dry storage method has only a short history, and in Japan, the method of storing a canister 1 sealed in a cask, generally called a cask storage method, is mainly used. The vault system is a system in which a storage room 2 in a building is securely shielded and a canister 1 is stored therein, instead of a cask, and various concepts have been proposed.
[0013]
In the vault storage method, the radiation dose is extremely high due to neutrons and gamma rays from spent fuel. For this reason, once the canister 1 is stored in the storage room 2, it is not preferable from the viewpoint of exposure that personnel directly enter the room. On the other hand, since the inside of the storage room 2 is cooled by natural ventilation by the outside air, there is a concern that the inside of the storage room 2 may be condensed, and not only various facilities in the storage room 2 but also the painting of floors and walls of the building may be left for a long time. If this occurs, deterioration may be a concern.
[0014]
Further, there is a similar problem in the maintenance / inspection of the inside of the supply air passage 8 or the exhaust air passage 9 facing the storage room 2 or the opening 18 and the hatch cover 11 of the transfer room floor 33 of the storage room 2. For this reason, during the storage period of the canister 1, the worker is required to inspect or maintain the floor, walls, ceiling, and facilities of the storage room 2 and the building in the air supply / exhaust air passage connected to the storage room 2 or to repair a defect found in the inspection. There was a strong need for measures to reduce the dose received.
[0015]
In addition, although the canister 1 is made of a material having excellent weather resistance, a method of monitoring for leakage should be considered. One of them is a method of monitoring the internal gas from each of the storage pipes 4 storing the canister 1. In this case, not only the storage pipe 4 but also an internal gas circulation device such as a pipe or a fan is required. In addition, since each storage pipe 4 needs to be inspected at all times, an alternative that is economically efficient and has a small burden on monitoring work has been desired.
[0016]
Further, as described above, in order to shield radiation from the storage room 2 through the supply air passage 8 and the exhaust air passage 9, a method of alternately installing a shielding floor 12 in a labyrinth shape in each air passage may be considered. However, in order to shield not only gamma rays but also neutrons circling around the floor, it is general that the number of shielded floors 12 to be combined is large. Become.
[0017]
On the other hand, since the pressure loss due to the flow of the cooling air can be reduced as the number of the shielding floors 12 decreases, the cooling air amount required to have a small number of floors in terms of cooling performance is secured, or the exhaust air passage 9 and the supply air This is preferable because the height difference of the passage 8 can be reduced, and as a result, the height of the exhaust air passage 9 can be reduced. Furthermore, since the structure has a high center of gravity due to the high exhaust air path 9 and the floors and walls that need to be shielded, it has been strongly desired that the height and the weight of the air path be reduced in terms of seismic design.
[0018]
Further, as described above, the transfer device in the transfer chamber 3 above the storage room 2 does not apply a load to the transfer room floor 33 which has many openings 18 and has a large span. It can be considered that the crane 13 is provided and supported. In this case, the opening and closing device of the canister 1 and the hatch cover 11 is hung by a wire, and it is necessary to manually perform positioning. In addition, there is an example in which a bridge-type device straddles the transfer chamber floor 33. However, if the span is large, the bridge height required for strength increases. For this reason, measures such as reducing the number of rows of storage canisters to suppress the span of the storage room 2 have been made. In this case, however, the storage room 2 is elongated and the seismic resistance of the building is deteriorated, and economical efficiency is also reduced. And the rational transport concept was required.
[0019]
The present invention has been made in view of such circumstances, and (1) equipment and structures such as a storage room of a spent fuel storage facility, facilities and structures in an air path leading to the storage room, a storage room ceiling and openings, and the like. The radiation dose from the storage canister during maintenance and repair of the building is reduced, and the dose received by workers is reduced. (2) In the event of leakage from the canister, storage pipes and many pipes, fans, etc. An object of the present invention is to provide a dry fuel storage facility that enables simple monitoring without requiring additional equipment. Preferably, the present invention also provides (3) a dry fuel storage facility configured to reduce the shielding height of the air supply / exhaust air path and to reduce the dose received by an operator during inspection and maintenance. Further, (4) the present invention provides a configuration in which the transfer device is downsized and the transfer chamber is made compact.
[0020]
[Means for Solving the Problems]
The present invention has been made in view of the above-mentioned object, and the invention according to claim 1 accommodates a plurality of canisters accommodating spent nuclear fuel in air and is surrounded by a wall having a radiation shielding function. A storage chamber, an air supply path for taking in air into the storage chamber, an exhaust air path for discharging air from the storage chamber, and a plurality of canisters arranged adjacent to the storage chamber, and A canister transfer chamber through which the canister passes when transported to a position, wherein the storage chamber is divided into a plurality of cells by a partition wall having a radiation shielding function, and the plurality of cells are divided into a plurality of cells. Are connected to both the supply air path and the exhaust air path.
[0021]
According to a ninth aspect of the present invention, a plurality of canisters for storing spent nuclear fuel are stored in the air, and a storage room surrounded by a wall having a radiation shielding function, and a supply chamber for taking air into the storage room. An air path, an exhaust path for discharging air from the storage chamber, and a canister transfer chamber disposed adjacent to the storage chamber and passing through the canister when transferring the plurality of canisters to a predetermined position in the storage chamber. In the spent fuel storage facility having, the storage room is divided into a plurality of cells by a partition wall having a radiation shielding function, and each of the plurality of cells is in both the supply air passage and the exhaust air passage. In the maintenance method for maintaining the connected spent fuel storage facility, a moving step of moving a canister in some of the plurality of cells to another cell, After the transfer step, characterized in that it and a step of performing maintenance within the part of the cell.
[0022]
Further, according to the present invention, a plurality of canisters for storing spent nuclear fuel are stored in air, and a storage room surrounded by a wall having a radiation shielding function, and a supply chamber for taking air into the storage room. An air path, an exhaust path for discharging air from the storage chamber, and a canister transfer chamber disposed adjacent to the storage chamber and passing through the canister when transferring the plurality of canisters to a predetermined position in the storage chamber. In the spent fuel storage facility having, the storage room is divided into a plurality of cells by a partition wall having a radiation shielding function, and each of the plurality of cells is in both the supply air passage and the exhaust air passage. In the maintenance method for maintaining the connected spent fuel storage facility, the temporary storage device may include a temporary ventilation device or a ventilation air conditioning device for some of the plurality of cells. And having a step of performing ventilation or ventilation air conditioning in Le, a step of performing maintenance in the cell, the.
[0023]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of a spent fuel storage facility or a maintenance method thereof according to the present invention will be described with reference to the drawings. Here, the same reference numerals are given to portions common or similar to the related art, or portions common or similar to the embodiments, and redundant description is omitted.
[0024]
[First Embodiment]
First, a first embodiment will be described with reference to FIGS. FIG. 1 is a vertical sectional view of the first embodiment of the present invention, FIG. 2 is a plan sectional view taken along line AA of FIG. 1 with the trolley 20 removed, and FIG. 3 is a line BB of FIG. It is an arrow flat sectional view. The storage room 2 is divided into a plurality of cells 35a to 35d by a plurality of mutually upright partition walls 15 having a shielding function. In FIG. 1, the upper end 15 a of the partition wall 15 on the supply air passage 8 side is near the lower end position of the supply air passage 8. Further, the upper end 15 b of the partition wall 15 on the exhaust air passage 9 side is near the lower end position of the exhaust air passage 9. The cold outside air taken in from the supply air passage 8 flows into each of the cells 35a to 35d, cools the heat generated from the canister 1 stored therein, and is discharged from the exhaust air passage 9.
[0025]
As shown in FIG. 2, in this example, partition walls 15 are arranged for each of the three rows of canisters 1. However, the number of columns is not limited to three.
Further, a sampling pipe 16 connected to a detector is provided near the entrance of the exhaust air passage 9 of each of the cells 35a to 35d so as to detect radioactive substances of the exhaust of the cell. When radioactive material leaks, it can be detected immediately.
[0026]
In the present embodiment, the storage room 2 is divided into a plurality of cells 35a to 35d, and sampling is performed for each cell, so that the group of canisters in which leakage has occurred can be limited to those in the cell. This facilitates the work of identifying the leaked canister.
[0027]
As shown in FIG. 1, a rail 19 is arranged on a ceiling 33 of a storage room, and a trolley 20 is placed on the rail 19, thereby moving the canister 1 in the storage room 2 to the transfer room 3 Can be moved through.
[0028]
FIG. 3 shows the arrangement of the rails 19 on the floor 33 of the transfer chamber of the canister 1 arranged above the storage room 2. However, illustration of the cart 20 is omitted in this figure. An opening 18 is provided on the floor 33 in accordance with the arrangement of the canister in the lower storage room 2, and the opening 18 is closed by an openable and closable hatch cover 11 having a shielding function. As can be seen from FIG. 3, the floor 33 is supported by the partition wall 15 thereunder, so that the span of one side is greatly reduced, and as a result, the strength of the floor 33 is improved. Therefore, by arranging the rails 19 of the transfer device in a direction perpendicular to the partition wall 15, the load of the carriage 20 of the transfer device can be easily supported by the floor 33 or the like.
[0029]
The rails 19 are installed between the hatches so that the carriage 20 can travel directly on any floor on the floor 33. As a result, the positioning of the transfer device becomes easy, and workability is greatly improved. In addition, the carriage 20 of the transfer device can be reduced in height as compared with a crane 13 (FIG. 14A) or a bridge type device that straddles the entire storage room 2, and the entire facility can be made compact.
[0030]
Further, the span of the crane 13 does not limit the span of the storage room 2, and the storage room 2 having a reasonable width, and thus the building dimensions can be planned. Further, when the canister 1 in the cells 35a to 35d to be maintained is moved to another cell, if the cells are arranged in the same manner, the target canister 1 is moved to another cell by moving the carriage 20 on the same rail 19. And the workability is greatly improved.
[0031]
Since the bogie 20 with the canister 1 mounted thereon has a high center of gravity, the bogie 20 is designed to have a large width in order to avoid overturning. In the example of FIG. 1, the wheels of the bogie 20 (shown in FIG. 1) are simultaneously mounted on four rails. ) Is to ride and run. In this way, the weight of the truck 20 carrying the canister can be dispersed and supported, so that the reinforcement of the structure that supports the rail 19 can be reduced. From the viewpoint of preventing the truck 20 with the canister 1 from falling, it is not necessary to provide wheels on two rails from the center of the truck 20.
[0032]
In FIG. 1, the outer wheels do not appear to ride on the rails 19 when the bogie 20 comes to the position of the endmost canister 1, but this is simply an illustration of the rails at both ends omitted. It is.
[0033]
When the carriage 20 is moved in a direction perpendicular to the direction of the rail 19 (the left-right direction in FIGS. 1 to 3), the carriage 20 is moved to an end position of the rail 19, and then moved to a lateral movement rail (not shown). The vehicle is mounted on a mounted laterally moving carriage and laterally moved along the laterally moving rail.
[0034]
FIGS. 4A to 4D schematically show different examples of the relationship between the rail 19 and the floor 33 of the transport device of the present invention. FIG. 4A shows an example in which the rail 19 is directly installed on the floor 33. FIG. 4B is an example in which a mold steel 43 is arranged on the floor 33 and the rail 19 is installed on the mold steel 43. In this case, the load is received by the floor 33 or the mold steel 43, but the partition walls 15 that partition the cells of the lower storage room 2 similarly support each other. FIG. 4C shows an example in which a mold steel 43 is buried in the floor 33 and the rail 19 is arranged on the mold steel.
[0035]
Further, FIG. 4D shows an example in which a mold steel 43 that bears the floor strength is embedded in the floor 33. In this case, it is possible that the steel floor 43 and the reinforced concrete of the floor 33 can bear the floor strength in combination. Become. For this reason, it is possible to reduce the width of the portion that bears the strength of the floor 33, and it is also possible to reduce the interval between the canister carrying-in / out openings 18. And the space of the storage canister 1 in the storage room 2 can be made small, and the facility can be downsized.
[0036]
Next, a maintenance method for the spent fuel storage facility will be described. In the spent fuel storage facility, facilities and structures such as canister foundations 5 and steel pipes 6 inside the cells 35a to 35d, cleaning and drainage of floor frame skeletons, openings 18 of the storage room ceiling 33, hatch covers 11, and the like. In order to perform inspection, cleaning, repair, and the like (hereinafter, also referred to as “maintenance”), an operator needs to enter the cells 35a to 35d. At this time, it is preferable that the dose received by the worker be kept as low as possible. As shown in FIG. 14C, in a structure in which the upper end of the storage tube 4 storing the canister 1 is supported from the ceiling of the storage room 2 and the lower end is swung by the two floors of the storage room, the storage tube 4 and the storage Equipment such as pipe steady rests is also included in the scope of maintenance.
[0037]
FIG. 2 shows a state where all the canisters 1 of this cell 35b have been moved to the other cells 35a, 35c, 35d in order to perform maintenance of one cell 35b. In other words, cleaning and drainage of equipment and structures such as the canister foundation 5 and the steel pipe 6 for heat removal in the cell 35b, and maintenance of the opening 18 and the hatch cover 11 of the storage room ceiling 33, etc. Even if the worker enters the cell 35b to perform the operation, the dose from the storage canister 1 such as the other cells 35a and 35c is shielded by the partition wall 15 having a shielding function, and the dose received by the worker is reduced. And safe work is possible.
[0038]
When the maintenance of the cell 35b is completed, for example, the maintenance of the cell 35c is performed. At this time, the canister 1 stored in the cell 35c is moved to the cell 35b whose maintenance has been completed. Thereby, the canister 1 in the cell 35c can be eliminated, and similarly to the maintenance of the cell 35b, the dose received by the worker can be reduced, and safe work can be performed. If the canister is moved and maintenance is sequentially performed for each cell as described above, the entire storage room 2 can be maintained, and it is easy to manage the entire storage facility for a long period of time.
[0039]
Also, instead of moving the canister of the cell to be maintained next to the cell for which maintenance has been completed sequentially, a spare cell is set, and the canister stored in the cell to be maintained is moved to the spare cell, and maintenance is performed. Upon completion, maintenance may be performed by a method of storing the canister from the spare cell back to the original cell.
[0040]
For example, if the spare cell is the cell 35a, the canister 1 stored in the cell 35b is moved to the cell 35a, and the cell 35b is maintained. After the maintenance of the cell 35b is completed, the canister 1 of the cell 35a is moved to the original cell 35b. Similarly, when the cell 35c is maintained, the canister 1 stored in the cell 35c is temporarily moved to the cell 35a during the maintenance.
[0041]
In this way, the same canister is stored in each cell before and after maintenance. For this reason, it is possible to easily grasp which spent fuel is stored in which cell, and it is possible to easily manage the spent fuel.
[0042]
Further, by maintaining the same amount of canisters that can be stored in each cell, canisters can be moved between cells without any excess or shortage during maintenance, and the space of the storage facility can be used without waste.
[0043]
[Second embodiment]
Next, a second embodiment will be described with reference to FIG. This embodiment is similar to the first embodiment, except that a partition wall 15 having a shielding function is provided not only in the storage room 2 but also in a range where the supply air passage 8 and the exhaust air passage 9 need to be shielded. It has been extended. That is, the upper end 15 a of the partition wall 15 on the supply air passage 8 side is at the upper end position of the supply air passage 8, and the upper end 15 b of the partition wall 15 on the exhaust air passage 9 side is at the upper end position of the exhaust air passage 9.
[0044]
In this way, the partition wall 15 of the supply air passage 8 and the exhaust air passage 9 is arranged continuously with the partition wall 15 of the storage room 2. Thus, a series of storage and cooling from the supply air passage 8 to the storage room 2 and the exhaust air passage 9 can be performed. The maintenance of the air passage at the same time as the storage room 2 receives the worker. The dose is reduced and safe work is possible. In addition, it is possible to easily manage a healthy storage facility over a long period of time. Further, sampling of exhaust gas for leakage of the canister 1 can be performed in the exhaust air passage 9.
[0045]
[Third Embodiment]
Next, a third embodiment will be described with reference to FIG. This embodiment is similar to the first and second embodiments, but the supply air passage 8 and the exhaust air passage 9 are different from these embodiments. That is, in this embodiment, a plurality of mutually parallel shielding plates 17 are arranged below each of the supply air passage 8 and the exhaust air passage 9, and a shielding floor 12 forming a labyrinth is provided above the supply air passage 8. 8 and two in the exhaust air passage 9. As shown, each shielding plate 17 is arranged upright and is parallel to the walls 37, 39 at the boundary between the supply air passage 8 and the exhaust air passage 9 and the storage room 2 or the transfer room 3, that is, used. It is arranged parallel to the outer wall 41 of the fuel storage facility.
[0046]
In order to secure the shielding effect while keeping the pressure loss in the air passage small, a plurality of parallel shielding plates 17 with a small interval between each other are used, so that the height of the air passage can also be reduced. A plurality of shielding floors 12 are arranged in a labyrinth structure above the shielding plate 17, and the same waterproofing and drainage as that of the roof are performed on the shielding floor 12, so that the lower shielding plate 17, the air passage, and the storage room 2 are provided. It is possible to suppress rainwater from entering, or to suppress a problem that foreign matter enters from outside and blocks the air path.
[0047]
For example, as shown in FIG. 7 and FIG. 8, waterproof coating or asphalt 60 is laid on the upper surfaces of the uppermost shielding floor 12 and the lower shielding floor 12 to make them waterproof and to be inclined to one side. A side groove 62 is installed on the side where the upper surface of the 12 is inclined and lowered, and a collecting funnel for collecting rainwater in the side groove 62 and a drain pipe 64 for draining rainwater from the collecting funnel are installed to drain rainwater. I do.
[0048]
It should be noted that the height of the shield plate 17 itself can be further reduced by providing the floor above the shield plate 17 with a shielding function, so that the height of the air passage that needs to be shielded as a whole can be reduced. In this embodiment, not only the height of the exhaust air passage 9 can be reduced, but also the upper portion can be made to have a lightweight structure by making the required height of shielding equal to or less than that of the roof of the transfer chamber 3. Thus, the earthquake resistance of the wind path can be improved, and safer facilities can be provided at low cost.
[0049]
At this time, the height of the shielding plate 17 and the number of shielding floors 12 can be appropriately changed according to the amount of heat generated in the storage chamber 2 and the temperature of the supply air, which are determined by the number of storage bodies of the canisters.
[0050]
In addition, since the upper ends 15a and 15b of the partition walls of the air passage are extended to the shield floor 12 above the shield plate 17, the dose received by the worker at the time of maintenance of the air passage such as the storage room 2 and the shield plate 17 is reduced. As mentioned above, as a result of proper maintenance, the soundness of the entire storage facility can be ensured over a long period of time.
[0051]
[Fourth Embodiment]
Next, a fourth embodiment will be described with reference to FIGS. This embodiment is similar to the third embodiment, but the air supply port 7 communicates with the transfer chamber 3 instead of opening to the outside air, and the transfer chamber 3 communicates with the outside. An air intake port 29 is provided.
[0052]
The air supply to the storage chamber 2 enters the transfer chamber 3 once from the air intake port 29, is further guided to the air supply port 7 from here, and is supplied to the storage chamber 2 via the air supply air passage 8. Once the air supply route is supplied through the transfer room 3, the ventilation of the transfer room 3 can also be naturally ventilated. Therefore, the whole storage facility can be ventilated by natural force, and the ventilation equipment for the transfer room 3 is not required, which is economical. Excellent. Further, rainwater and foreign matters are less likely to enter the storage room 2, which is preferable in radiation management of water and waste.
[0053]
[Fifth Embodiment]
Next, a fifth embodiment will be described with reference to FIG. This embodiment is similar to the fourth embodiment (FIGS. 9 and 10), except that the arrangement direction of the shielding plate 17 is rotated by 90 ° from that of the fourth embodiment so that it is parallel to the partition wall 15. It was done. Also in this case, the shielding plate 17 is parallel to the direction of air flow (vertical direction), and the same effect as in the fourth embodiment can be obtained.
Further, even if the shielding plate 17 of the third embodiment (FIG. 6) is the same as the arrangement direction of the shielding plate 17 of the present embodiment, the same effect as that of the third embodiment can be obtained.
[0054]
[Sixth Embodiment]
Next, a sixth embodiment will be described with reference to FIG. This embodiment is similar to the fourth embodiment (FIG. 9), except that a temporary ventilation or air conditioner 21 is installed, for example, in the transfer room 3 during maintenance of the spent fuel storage facility of the present invention. Then, ventilation or air-conditioning in the storage room 2 or in the cell where the worker enters as a maintenance target in the air passage is performed. However, illustration of the cart 20 is omitted in FIG. In the example of FIG. 12, a temporary ventilation or air conditioner 21 is installed in the transfer room 3 above the storage room 2, and the air in the storage room 2 is circulated through the opening 18 to perform air conditioning while removing dust and the like.
[0055]
In this case, a part of the air in the storage room 2 is ventilated. If the suction side of the temporary ventilation or air conditioning device 21 is opened to the transfer chamber 2 and the opening 18 on the temporary ventilation or air conditioning device 21 shown in FIG. The exhausted air is exhausted through the exhaust air passage 9.
[0056]
[Seventh Embodiment]
Next, a seventh embodiment will be described with reference to FIG. This embodiment is similar to the third embodiment (FIG. 6), except that a temporary ventilation or air conditioner 21 is provided at the outlet of the air supply passage 8. In this case, air is forcibly supplied through the supply air passage 8 and exhausted through the exhaust air passage 9.
[0057]
[Other embodiments]
The arrangement of the canisters 1 is not limited to the above-described embodiment, and the number of rows of the canisters 1 can increase the degree of freedom with respect to performance such as cooling. Alternatively, the canisters 1 can also be arranged in a staggered arrangement instead of a square arrangement. Further, the canisters 1 can be stacked in a plurality of stages in the vertical direction, and as a stacking method, the canisters 1 in a plurality of stages can be directly stacked, or a horizontal support plate may be arranged between the upper and lower canisters 1. . The same effects as those of the above-described embodiment can be obtained for these.
[0058]
Further, the features of the above-described embodiments can be combined in various ways. For example, the sixth and seventh embodiments show examples in which a temporary ventilation or air conditioner 21 is applied to the fourth and third embodiments, respectively, but are applied to other embodiments. It is also possible. Further, the combination structure of the transfer chamber floor 33 and the rail 19 described in the first embodiment (FIG. 4) can be applied to other embodiments. Furthermore, the maintenance method for the spent fuel storage facility described in the first embodiment (FIG. 2) can also be applied to other embodiments.
[0059]
【The invention's effect】
As described above, according to the present invention, in a spent fuel storage facility of a vault storage method, a radiation dose from a storage canister during maintenance of a structure or the like in a storage room is reduced, and a dose received by an operator is reduced. And simple monitoring of the leakage of the canister is possible. Thus, it is possible to provide a dry fuel storage facility excellent in economy, safety, earthquake resistance, and long-term soundness, and a maintenance method thereof.
[Brief description of the drawings]
FIG. 1 is a vertical sectional view of a first embodiment of a spent fuel storage facility according to the present invention.
FIG. 2 is a plan sectional view taken along line AA of FIG. 1;
FIG. 3 is a plan sectional view taken along the line BB in a state where the bogie of FIG. 1 is removed.
FIG. 3 is a vertical sectional view of a second embodiment of the spent fuel storage facility according to the present invention.
FIG. 4 is an enlarged sectional view showing a transfer chamber floor and a rail portion of FIG. 1, wherein (a) to (d) show different embodiments.
FIG. 5 is an elevational sectional view of a second embodiment of the spent fuel storage facility according to the present invention.
FIG. 6 is a vertical sectional view of a third embodiment of the spent fuel storage facility according to the present invention.
FIG. 7 is an enlarged vertical sectional view of a portion C in FIG. 6;
FIG. 8 is an enlarged vertical sectional view of a portion D in FIG. 6;
FIG. 9 is a vertical sectional view of a fourth embodiment of the spent fuel storage facility according to the present invention.
FIG. 10 is a cross-sectional plan view taken along line EE in a state where the bogie of FIG. 9 is removed.
FIG. 11 is a plan sectional view of a fifth embodiment of the spent fuel storage facility according to the present invention, and is a view corresponding to FIG. 10;
FIG. 12 is a vertical sectional view of a sixth embodiment of the spent fuel storage facility according to the present invention.
FIG. 13 is a vertical sectional view of a seventh embodiment of the spent fuel storage facility according to the present invention.
14A and 14B are views showing a conventional spent fuel storage facility, wherein FIG. 14A is an elevational sectional view, FIG. 14B is an enlarged perspective view showing the canister and the steel pipe of FIG. () Is a partially enlarged vertical sectional view showing another example of the canister storage method.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Canister, 2 ... Storage room, 3 ... Transport room, 4 ... Storage pipe, 5 ... Canister base, 6 ... Steel pipe, 7 ... Air supply port, 8 ... Air supply path, 9 ... Exhaust air path, 10 ... Exhaust port , 11 ... hatch cover, 12 ... shielding floor, 13 ... crane, 14 ... trolley, 15 ... partition wall, 16 ... sampling piping, 17 ... shielding plate, 18 ... opening, 19 ... rail, 20 ... truck, 29 ... air intake Mouth, 31 ... ground, 33 ... transfer room floor (storage room ceiling), 35a, 35b, 35c, 35d ... cell, 37 ... boundary wall, 39 ... boundary wall, 41 ... outer wall, 43 ... steel, 50 ... storage room entrance 52, storage chamber outlet, 60, waterproof paint or asphalt, 62, gutter, 64, drain pipe.

Claims (11)

A storage room surrounded by walls that stores a plurality of canisters that store spent nuclear fuel in the air and has a radiation shielding function,
An air supply passage for taking air into the storage chamber,
An exhaust air passage for discharging air in the storage chamber;
A canister transfer chamber that is disposed adjacent to the storage chamber and passes through the canisters when transferring the plurality of canisters to a predetermined position in the storage chamber.
A spent fuel storage facility having
The storage room is partitioned into a plurality of cells by a partition wall having a radiation shielding function, and each of the plurality of cells is connected to both the supply air passage and the exhaust air passage.
A spent fuel storage facility. The spent fuel storage facility according to claim 1, wherein the plurality of cells are arranged in parallel in a horizontal direction, and the canister transfer chamber is disposed right above the plurality of cells. Facility. 3. The spent fuel storage facility according to claim 2, wherein an air intake is arranged in the canister transfer chamber, and the air supply passage is connected to the canister transfer chamber. . 4. The spent fuel storage facility according to claim 2, wherein a rail on which a transport device that transports the canister to the plurality of cells can run is arranged in the canister transport chamber in a direction intersecting the partition wall. 5. Spent fuel storage facility characterized by the following. The spent fuel storage facility according to any one of claims 1 to 4, further comprising a detector for monitoring exhaust gas of each of the plurality of cells. The spent fuel storage facility according to any one of claims 1 to 5, wherein at least a part of the supply air passage and the exhaust air passage is partitioned by a partition wall having a radiation shielding function in accordance with the partition of the cell. A spent fuel storage facility. 7. The spent fuel storage facility according to claim 1, wherein a plurality of shielding floors have a radiation shielding function while forming a bent air path in at least one of the supply air path and the exhaust air path. A spent fuel storage facility, wherein 8. The spent fuel storage facility according to claim 7, wherein a plurality of parallel shielding plates having a radiation shielding function are arranged substantially vertically below the shielding floor. A plurality of canisters for storing spent nuclear fuel are stored in the air, a storage room surrounded by a wall having a radiation shielding function, an air supply passage for taking air into the storage room, and discharging air in the storage room. An exhaust air passage that is disposed adjacent to the storage chamber, and a canister transfer chamber that passes the canister when transferring the plurality of canisters to a predetermined position in the storage chamber. The storage facility, wherein the storage room is divided into a plurality of cells by a partition wall having a radiation shielding function, and each of the plurality of cells is connected to both the supply air passage and the exhaust air passage. In the maintenance method for maintaining
A moving step of moving a canister in some of the plurality of cells to another cell,
After the moving step, a step of performing maintenance in the partial cells;
A maintenance method for a spent fuel storage facility, comprising: The method for maintaining a spent fuel storage facility according to claim 9, wherein the other cell to which the canister is moved in the moving step is a spare cell, and after the step of performing maintenance in some of the cells, A method for maintaining a spent fuel storage facility, further comprising a step of returning a canister in the spare cell to the cell in which maintenance has been performed. A plurality of canisters for storing spent nuclear fuel are stored in the air, a storage room surrounded by a wall having a radiation shielding function, an air supply passage for taking air into the storage room, and discharging air in the storage room. An exhaust air passage that is disposed adjacent to the storage chamber, and a canister transfer chamber that passes the canister when transferring the plurality of canisters to a predetermined position in the storage chamber. The storage facility, wherein the storage room is divided into a plurality of cells by a partition wall having a radiation shielding function, and each of the plurality of cells is connected to both the supply air passage and the exhaust air passage. In the maintenance method for performing maintenance, ventilation or ventilation air conditioning in the cells is performed by a temporary ventilation device or a ventilation air conditioning device in some of the plurality of cells. And a step,
Performing maintenance in the cell;
A maintenance method for a spent fuel storage facility, comprising:

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