JPS58176594A - Storage facility of container for radioactive material - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to storage equipment for containers of radioactive materials. In this invention, the term "container" refers to a container with various shapes and dimensions that has the necessary performance as a radiation shielding container, and includes both cases in which radioactive material is contained and cases in which it is not contained. However, in the following, cask (c
a s k ). Furthermore, shielding as used in the present invention means blocking or reducing radiation leakage.

In recent years, with the development of methods for utilizing radioactive materials, the need for transporting radioactive materials has increased. For example, a large amount of radioactive material is used as nuclear fuel in a nuclear power plant, and this use requires transporting the nuclear fuel in and out. When carrying in and out, nuclear fuel is stored in casks and
transported. The same applies to spent nuclear fuel reprocessing plants. In order to smoothly transport radioactive materials between factories that handle these materials, it is absolutely necessary to store casks that may or may not contain radioactive materials. The present invention aims to provide storage equipment used for such storage, which is far superior to conventional equipment in terms of safety against earthquakes, site area utilization, ease of loading and unloading work, etc. The purpose is

11 Kihe Sufu are manufactured in various shapes, but they must have the ability to shield radiation from the radioactive materials stored inside, and they are usually of a certain size and weight. For example, those used to transport nuclear fuel for nuclear power plants:
Diameter 73-. 2.3; m1 length! ~7m・Weight 70~
A cask weighing around 720 tons will be used.

If radioactive materials are still stored inside the cask, even if the cask itself has the ability to shield radiation, due to the nature of radiation itself, it is impossible to completely prevent radiation from leaking outside the cask. Otherwise, it will be necessary to handle the cask with some radiation leakage.

Therefore, it is impossible to completely eliminate the radiation exposure of workers when handling this compost, so it is possible to simplify the work and shorten the working time by means such as automation or remote control. It is important to reduce the amount of radiation that people are exposed to. For the same reason, in order to reduce the amount of radiation exposed to living organisms that permanently live around the cask storage facility, it is necessary that the storage facility itself has sufficient radiation shielding performance, and that this shielding performance is It needs to be maintained even in the face of such natural phenomena.

Due to the above-mentioned requirements, a storage facility shown in FIG. 7 has been used in the past. Figure 1 is a schematic plan view near the floor of a conventional facility consisting of pillars and walls and having a rectangular horizontal cross section, showing the right half of the facility that is symmetrical with respect to the central vehicle passage 2 as an axis. . In this figure, / is the outer wall that has a radiation shielding ability, -2 is a column that has a radiation shielding effect on the outer wall (hereinafter referred to as an outer column), 3 is a column that is inside the outer wall (hereinafter referred to as an inner column), and Il is a cask in storage,
S is the lower ventilation]-1, /7 is the auxiliary shielding wall to shield the radiation leaking from this vent, and B is the entrance and exit of the cask or the vehicle carrying it [1]. The conventional equipment shown in FIG. 1 has the following drawbacks. This type of storage facility is particularly superior in terms of its ability to withstand earthquakes (hereinafter referred to as earthquake resistance), and the outer walls and pillars, as well as the roof (not shown), are shielded from radiation. It is necessary to provide performance, and the weight of the roof is extremely large. Therefore, in the case of conventional equipment with a rectangular horizontal cross-section, it is necessary to install a large number of inner columns 3 to improve earthquake resistance, or to install a special high-strength structure on the outer wall/and outer column 2 without providing inner columns 3. No matter which method is adopted, the disadvantage is that the foundation of the equipment, the materials and man-hours required for constructing the building will increase. In addition, in the conventional equipment shown in Fig. 1, a child truck is loaded onto a transportation vehicle, and both the cask and the pallet on which the cask is placed are loaded on the child car, and the vehicle enters passage 2, so that only the child truck carries the cask. After loading the pallets and entering the auxiliary passageway, . This is a facility where casks are carried in (in the case of cask removal, the procedure is reversed). In this example, inner column 3
If there is a passageway 9 and the auxiliary passageway 2.2, it is necessary to install the passageway 9 and the auxiliary passageway 2.2 while avoiding the inner column, resulting in a disadvantage that the number of casks stored is reduced compared to the floor space. Furthermore, if the outer wall needs to be opened to cool the casks during storage and to ventilate the building, there is also the drawback that it becomes more difficult to maintain the earthquake resistance of the building. In short, it is difficult to realize this type of equipment that uses a building with a rectangular horizontal cross section, has sufficient seismic resistance against seismic waves coming from all directions, and is highly efficient in the use of floor space. Therefore, conventional devices have a large portion with no moon and are expensive.

The purpose of this invention is to eliminate the various drawbacks of these conventional facilities.The gist of this invention is to make the shape of the horizontal section of the building circular or polygonal, so that it can be highly earthquake resistant without installing inner pillars. It has a building structure, and a turning platform for vehicles loaded with casks is installed in the center of the circular or polygonal building floor, and a vehicle road is installed radially from this turning platform to the vicinity of the outer wall, This equipment simplifies the various operations involved in carrying in or transporting casks (liquid ζ) and improves the efficiency of floor space utilization.

The specific content of this invention will be explained with reference to FIGS. 2 and 3. Both figures are examples of the equipment of the present invention based on the above technical considerations, and the present invention is not limited by these figures. FIG. 2 is a schematic plan view of the vicinity of the floor surface of this specific example. FIG. 3 still shows a vertical section through the installation of FIG. 1, taken in the direction of the arrow A--A in FIG. In both figures, / is an outer wall with a circular horizontal cross section that has a radiation shielding effect, supports the weight of the upper part, and serves as a load-bearing wall against earthquake forces. , 2 is the outer column 2 in Fig. 1
It is a load-bearing wall with a similar function. No inner columns are used, and all the upper weight and seismic forces are supported by these two load-bearing walls. G is the cask mounted on a pallet, S is the lower ventilation hole, and O is the entrance of the cask loading vehicle.

In addition, 7 is a turning table 9g of this vehicle, which is a door that may or may not have a radiation shielding effect and is installed depending on the contents of the various facilities installed adjacent to the entrance B, and 9 is a door from the outer periphery of the turning table 7. The vehicle path /θ leading to the outside of the outer wall / is a radial vehicle path extending from the outer periphery of the turntable 7 to the vicinity of the outer wall /. That is, this example has a structure in which a transport vehicle entering from the passage 2 can change direction on the turning platform 7 and then enter or leave any of the 77 radial passages 10, and is used in the following operating procedure. In other words, a vehicle loaded with casks on a pallet enters and exits from outside the building [1. When arriving at B, the door is first opened, and the vehicle is placed on the turntable 7. move forward until Next, the pallet lifting device installed on the vehicle is driven to increase the loading height of the pallet, and then the direction change table is rotated horizontally to select a desired radial path and enter the radial path. At this time, the situation is as follows:
0 arrow? W, ++ 7th figure as seen in the direction of -11
Show the diagram.

Figure 7 is an example in which a railway vehicle is used as the Φ vehicle.
A fixed loading platform from a rail that is fixed on a turning platform.
FIG. 2 is a vertical cross-sectional view of a state in which a transport vehicle having a vehicle carrying a vehicle has entered over a radial path. This vehicle is equipped with a fixed loading platform/2, a loading platform/3 that can be raised and lowered, and a driving device/da for raising and lowering the loading platform/3. /3, and this elevating cargo platform arrives on the direction change platform 7 in a lowered state. While the direction change table 7 is rotating horizontally, the drive device /g is driven to raise the lifting platform 3, and after stopping the horizontal rotation of the direction change table 7 at a desired position, the elevated state of the lifting platform is The vehicle moves along the desired radial path/
Enter θ. Figure 9 shows the situation after the approach is completed, and /S
This is a cask pedestal fixed on the floor of tobacco equipment.

Here, if the drive device/da is driven to lower the lifting/lowering platform/3 to the lowered position, the pallet/O is placed in a stable state on the cask pedestal/S with the cask on it.
The upper surface of the lifting platform/3 and the lower part of the pallet/B are separated. The vehicle which has completed the unloading of the casks in this manner is able to change direction using the turntable 7 in the reverse order as described above, and then drive out of the facility through the vehicle entrance/exit 6. Furthermore, when carrying out a cask in storage to the outside of the facility, the cask can be carried out of the facility by following the procedure reverse to the above. The above operations can also be performed automatically or by a remote party.

The radioactive material contained in the cask undergoes some degree of nuclear fission reaction, so the cask that contains the radioactive material usually generates some heat. Therefore, in this type of storage facility, the casks may be stored while being cooled. For example, in the case of a cask that stores spent nuclear fuel in a nuclear power plant and has a diameter of -2 m and a length of about 6 m, the equation is approximately 1 < WIV, and the cask can be cooled by air cooling. FIGS. 2 and 3 show examples in which this cooling is performed by natural ventilation. In FIGS. 3 and 3, a lower vent S is installed in the lower part of the outer wall near the end of each radial vehicle 1 route. The lower ventilation port S is shown as an opening j indicated by a dotted line in FIG. In order to shield radiation leaking from each of these lower vents, in this example, auxiliary shielding walls /7 are installed outside the outer wall /7 at a desired distance from the outer wall, the same number as the number of lower vents. However, in this specific example, rainwater is prevented from flowing into the inside of this facility,
In addition, in order to maintain the aesthetic appearance, the outer periphery /g is made of a material that does not require a special radiation shielding effect between each auxiliary shielding wall / 7 and between each auxiliary shielding wall and the eaves part of the roof 2θ, 2 /. An air intake louver /9 is provided on the outer periphery of the upper part of the auxiliary shielding wall /7.

However, this outer circumference/g and air intake louver/9 are not essential in this invention. On the other hand, a partial ventilation [2] and a wind shield plate 23 are installed in a part of the roof θ.

” The two-part vent has a structure that can also shield radiation leaking outside the cask from any of the casks during storage (details later)
It becomes.

As described above, by installing the lower and upper vents, the air flowing into the building from the galley/9 reaches the outer periphery of the radial vehicle passage from the lower part of the building and passes through the gap between the pallet/6 and the cask. At the same time, the cask heats up slightly due to the heat generated, and the natural circulation continues as it rises and flows out of the building through the upper vent, and the cask is sufficiently cooled by this natural circulation. However, these ventilation [1st Gala IJ]
The upper ventilation 0.2 mm and the wind shield plate 23 on the outer periphery are not essential to the present invention.

The first advantage obtained by this invention is that the number of casks that can be stored per unit floor area can be increased.
゜For example, the diameter is 2.3m.

Length 7? ? 7 small fireflies/, 2θ tons of casks/θ~//
In a facility capable of storing approximately 1,000 pieces, the required floor area of the facility of the present invention is f! It may be about 7θ of i. The second advantage is that the weight of the building is reduced and, concomitantly, the foundation of the building is also lighter, resulting in a concrete versus steel frame.

Compared to conventional equipment, the y-required amount of materials such as reinforcing bars and the number of man-hours required for construction are less than the 7θ coefficient, making the equipment cheaper overall. These advantages are mainly due to the use of buildings with circular or polygonal horizontal cross sections for the outer walls, which improves the distribution of stress that occurs in the main parts of the building during an earthquake, and allows for the use of relatively small amounts of building material without the need for inner columns. It has become possible to construct buildings with sufficient earthquake resistance through the use of casks, and as a result of eliminating the need for internal columns, casks being stored in circular or polygonal buildings can be arranged radially at small intervals. This was obtained as a combined effect with the fact that However, when providing ventilation 1 on the outside wall to store the cask while cooling it as described above, the seismic resistance of the conventional building with a square horizontal cross section is significantly impaired, whereas the circular shape of the present invention Alternatively, for polygonal buildings, the reduction in seismic resistance due to the installation of these ventilation holes is extremely small, and can be easily countered by slightly increasing the thickness of the load-bearing walls. As a result, the inventive installation is particularly advantageous when carrying out ventilation cooling of casks.

There are many embodiments of this invention. The main aspects of the embodiment will be described below. In addition to self-propelled vehicles capable of traveling on ordinary roads (e.g., trucks, L-railer trucks), the vehicles for transporting casks in this invention fIII include self-propelled vehicles that travel on railway rails, or traction vehicles. Jll can. 2) Middle wheel entry/exit passageway, middle wheel turning platform 7, and radial vehicle passageway in the figure/
θ can be installed using the well-known structure A and L method so that seven or more of the above-mentioned vehicles can pass alone or in common. In the case of a self-propelled Φ vehicle, after changing direction on the turning platform, the center shaft usually enters the radiator or passage in either a forward or backward state. Self-propelled A:, LIT f In the case of a toxic towing medium wheel, many well-known methods θ can be used as a method to pull the vehicle into a radial path, but for example, / on a turning platform.
A simple method is to install wire winding equipment such as a winch in a corner, use the winch to wind up the wire that is permanently placed in each radial passage, and then move the towing vehicle into the radial passage.

Furthermore, although the example shown in Fig. 3 has been explained with regard to the storage position of casks in the equipment of this invention, in this invention, the storage position of casks is not only on the radial passages, but also on the radial passages. The cask pedestal/Jl can be moved in the direction perpendicular to the transfer roll or transverse rail installed on J-1- and the radial 4-way passage installed on the cask pedestal. It is also possible to use a reciprocating oil 1 device or the like to move both the pallet A and the cask containers placed on it in a direction perpendicular to the radial passage and store them on both sides of the radial passage. By such means, the number of casks that can be stored can be increased.

In this invention, many shapes of the outer wall and the roof can be adopted. In other words, in addition to the Mt. Fuji shape shown in Figure 3, roof shapes with a circular horizontal cross section include truncated conical, hemispherical, and bell-shaped roofs.
Preferred shapes having a polygonal horizontal cross section include polygonal pyramids and truncated polygonal pyramids having at least five interior angles. In this invention, the outer wall does not necessarily have to be upright. In other words, the example in Figure 3 shows the case where the outer wall is an upright cylindrical shape, but as an upright case, a polygonal cylindrical shape having at least five internal angles can be used, or in other cases where it is not compatible. Each of the described (using the lower part of the Φ-shaped one as the outer wall) 1 can be used. The outer wall may have a structure using outer columns for convenience, but it may also be a structure without columns (so-called / L structure), and in the case where the cross section is polygonal. It is desirable to use a regular polygon, such as a g-gon or larger, in order to distribute stress against seismic forces applied from all directions.For the shape and structure of the roof and outer walls, it is possible to use a combination of the shapes and structures described in 1-1. However, it is particularly advantageous to construct the roof and the outer walls as a seven-piece structure symmetrical about a vertical axis passing through the center of the turning platform of the transport vehicle, and furthermore, to construct the roof and the outer walls as a seven-piece structure symmetrical to a vertical plane that includes said vertical axis. The structure is constructed as a seven-body structure with a curved surface formed by a curved line having a slope suitable for the roof and the outer wall when the vertical axis is rotated.For example, FIG. This is an example of a seven-body structure in the shape of an inner truncated pyramid. Figure 7 is a horizontal sectional view taken along the A-A arrow in Figure 6. Both figures are shown in Figure 2.3.5. The parts that have the same function as the example are numbered, and the explanation will be omitted as it is thought to be easily understood. The structure as a whole is significantly simpler than the example shown in Figure S, with a good appearance, and has a higher earthquake resistance.If the horizontal section of the outer wall is triangular or q-gonal, The stress dispersion within the building against the seismic force applied from the JJ direction is insufficient, making it easy for the building to collapse, and it is also disadvantageous as it tends to create floor surfaces that are difficult to use near the apex of each interior corner. It is necessary to install at least three such passages, and if the number is less than this,
It is difficult to fully realize the advantages of this invention.

It is desirable that the upper vent installed at a high position on the roof have a structure that can prevent radiation leakage, as in the previous JL. Radiation leaking from each cask travels linearly in all directions. Of this leakage radiation, the radiation that reaches the upper ventilation [] people [] (located inside the building) is
If the +ni product is on or the angle between the direction of radiation propagation and the central axis of the internuclear I] is small, even if the area of each vent opening is small, the angle between the direction of radiation and the central axis of the internuclear I is This will result in leakage to. Generally, it is necessary to provide a lid at a certain distance from the discharge end of the vent to shield leakage radiation that does not obstruct ventilation. The need for such a lid can be explained by providing a large number of vents [] with small opening areas, by increasing the length of the vent hole, or by making the angle between the central axis of the vent [-1] and the radiation line a dog. It can be reduced by such methods. For example, when a large number of ventilation holes with small opening areas are arranged in parallel, the need for the lid is almost eliminated when the central axis of each ventilation hole is horizontal or the ventilation direction is below horizontal. Conversely, the need for this lid increases as the area of the opening for ventilation increases. These lids can also be used as wind shields to prevent wind from interfering with ventilation.

However, the relaxation of the opening area of each ventilation section increases as the required amount of ventilation increases. Said sixth and seventh
The example shown in the figure is one in which a large number of upper ventilation holes with a large area of 1-1 are installed in order to sufficiently cool the cask by increasing the amount of airflow through natural convection. This is an example in which a plate 23 is provided.

Although the ventilation method using natural convection was explained above as a ventilation method for the ridge, it is also possible to use a method using forced convection. It is convenient to install an air blower appropriately between the auxiliary shielding walls and to perform the push-in and blow-off. In the case of using such a forced ventilation method, the relaxation of the opening area of the upper ventilation hole can be reduced. There are no particular restrictions on the construction materials for the trench, the building according to the present invention, its foundation, floor, etc., and for example, well-known concrete, reinforcing bars, steel frames, etc. may be used. Further, as concrete, it is possible to use concrete whose radiation shielding effect is enhanced by mixing a small amount of a boron-containing compound. The foundations, walls, and roofs of buildings can be constructed in a variety of well-known structures, such as reinforced concrete structures, prestressed concrete structures, steel frame structures, and steel reinforced concrete structures.

[Brief explanation of drawings]

FIG. 1 is a schematic plan view of the vicinity of the floor of a conventional cask storage facility, FIG. 2 is a schematic plan view of the vicinity of the floor of a cask storage facility according to the present invention, and FIG. is a vertical cross-sectional view taken along arrow A-A of the equipment according to FIG. 2, and FIG. 9 is a vertical cross-sectional view taken along arrow B-B. Fig. S is a front view seen from the vehicle entrance/exit direction in Figs. 2 and 3, Fig. 6 is a schematic vertical sectional view of another example according to the present invention, and Fig. 7 is a view taken in the direction of the arrow in Fig. 6. It is a horizontal cross-sectional view taken along AA. /Outer wall 2 Pillar on the outside wall (outer pillar) 3 Pillar on the inside of the outside wall (inner pillar) q Cask S Lower ventilation port 6 Cask and vehicle entrance/exit 7 Direction change platform for transportation tonkomas g Radiation shielding effect Door sow Vehicle entrance/exit passage 10 Radial vehicle passage // Shi - Lua, 2 fixed loading platform/3 Elevating platform/G Same as above, Drive device/S Cask pedestal/B Pallet/7 Auxiliary shielding wall 7g Parts other than the auxiliary shielding wall Perimeter of / 2 Air intake louver, 20 Roof, 2/ [1" upper part of roof, 2.2 Auxiliary passage, 23 Wind shielding board 2q, J = ventilation 11 Figure 3 Figure Figure 4 Figure Figure 5 Sai・6 figure

Claims (1)

[Claims] ■ An outer wall that has a radiation shielding effect and whose horizontal cross-sectional shape is circular or a polygon of J-gon or more, and a roof that has a radiation shielding effect that covers at least the upper part of the inner space of the outer wall. , a turning platform for a transport vehicle located in the sixth part of the floor within the outer wall, three or more radial vehicle passages extending from the 9th circumference of the turning stand to the vicinity of the outer wall, and the turning table; 1. A storage facility for radioactive material containers, characterized by comprising a vehicle passageway extending radially from the outer periphery of the building through the outer wall and leading to the outside of the outer wall. Q) A group of lower ventilation holes provided at desired locations on the lower part of the PF outer wall, 1 fl.
Claim 1: A group of auxiliary shielding walls installed inside or outside of the air vents at a desired distance from each ventilation hole, and an upper ventilation hole installed at a desired high position on the roof. Radioactive material container storage equipment as described. (2) A storage facility for radioactive substance containers according to claim 2, which has the upper vent provided with means for shielding radiation emitted from the group of containers.