JPH10332894A - Storage facility or radioactive material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a storage facility of radioactive material which is capable of efficiently cooling the radioactive material, increasing the storage capacity of storage vessel and storage density and is not necessary to get a site for constructing a storage facility. SOLUTION: In a storage facility 2, a floating type storage room 9 is constituted so as to layer steel storage vessels 3 in vertical direction and a lifter 18 is provided to move a cask for transportation 20 having carried steel storage vessels 3 from a reactor power station 1 in two directions of up and down and horizontally in the passage of the float type storage room 9. The steel storage vessel 3 is contained and stored in an overpack filled with either of helium gas, nitrogen gas or air arranged in the float type storage room 9. Around this overpack, either of pure water, sea water or air is filled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a facility for storing radioactive materials such as spent fuel and high-level radioactive waste generated from a nuclear power plant.

[0002]

2. Description of the Related Art A conventional radioactive material storage facility is disclosed, for example, in Japanese Patent No. 2502121 (registered March 13, 1996).
As shown in the horizontal modular type spent fuel storage system disclosed in Japanese Patent Application Laid-Open (JP-A) No. 2000-214, the system was premised on being installed on the ground, and therefore had the following problems.

[0003] Since radioactive materials such as spent fuel and high-level radioactive waste are cooled by air, the cooling capacity is limited, and when storing spent fuel that generates a large amount of heat, the temperature rise of the spent fuel is suppressed. Therefore, the number of fuels that can be stored in one storage container (canister) is limited. Even if a general anticipated seismic load is applied, the storage facility must have a rigid structure to maintain the integrity of the storage containers (canisters) and radioactive materials such as spent fuel and high-level radioactive waste. For this reason, it was difficult to increase the number of layers, and in order to construct a storage facility with a large storage capacity, a large site was required. Because the building (concrete module) shields radioactive materials, the wall thickness of the building (concrete module) is required to be greater than the required earthquake-resistant thickness, which increases the physical quantity and increases construction costs. I was In order to prevent radiation exposure around the site, it was necessary to take measures such as constructing a storage facility in a place with mountains and hills around it or covering the surroundings with embankments. In particular, in the case of storing spent fuel, there is a possibility that the concrete temperature rises due to radiant heat from the storage container (canister), and that the soundness of the concrete is impaired.

[0004]

SUMMARY OF THE INVENTION Accordingly, the present invention is capable of efficiently cooling a radioactive substance, increasing the storage capacity of a storage container (canister), and making a high-height storage. Multi-layer storage of storage containers (canisters) is possible, storage density can be increased, and it is not necessary to increase the thickness of storage facility walls more than necessary, and it is necessary to secure a site for storage facility construction. In addition, it aims to provide a storage facility for radioactive materials that does not require any measures such as constructing a storage facility in a place with mountains and hills around it, or covering the surroundings with earth embankment.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a radioactive material storage facility of the present invention is provided on a sea surface for horizontally storing a steel storage container sealed with radioactive materials generated from a nuclear power plant. A floating floating storage, wherein the surroundings of the storage are configured to cool radioactive materials by natural convection of seawater or air.

[0006] In the above-mentioned radioactive material storage facility of the present invention, it is preferable that the floating storage is configured to store the steel storage containers in a vertically stacked manner. Further, it is preferable to provide a lifter that can move the transport cask that has transported the steel storage container from the nuclear power plant in two directions, up and down and horizontal, in the passage of the floating storage. Further, it is preferable that the steel storage container is stored and stored in an overpack that is filled with any one of helium gas, nitrogen gas, and air disposed in a floating storage. Also, around this overpack,
It is preferable that any one of pure water, seawater, and air is filled. Further, it is preferable that a floating storage is connected to the land by a bridge.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a radioactive material storage facility according to the present invention will be described with reference to the drawings. In FIG. 1, reference numeral 1 denotes a nuclear power plant, and 2 denotes a spent fuel or a high level generated from the nuclear power plant 1. This is a floating storage facility that horizontally stores a steel storage container (canister) 3 that stores and seals radioactive materials of radioactive waste, and this storage facility 2 is floated on the sea surface spreading around the nuclear power plant 1. , Land 4
And a breakwater 5 moored by a mooring line 6 and connected to the land 4 by a bridge 7. The storage facility 2 is provided with storages 9, 9 comprising pure water tanks opposed to each other with a central passage 8 therebetween, and a storage shelf 10 for storing a steel storage container (canister) 3 in both storages 9, 9. Figure 2
As shown in FIG. 3, a plurality of stages are provided in the vertical direction.
A total of 27 steel storage containers (canisters) 3 can be stored in a row, a plurality of rows in the horizontal direction, 9 rows in the illustrated example, and each storage shelf 10 is provided with helium gas as shown in FIG. , Nitrogen gas, or air, and each overpack 11 is supported by a structure (not shown). Overpack 11
Is a steel cylindrical container, as shown in FIG. 4, which is hermetically attached to a partition 9a between a central passage 8 and a storage tank 9 of a pure water tank, and a flange 11 of an overpack 11 is provided on the passage 8 side.
a, the lid 12 is attached by a bolt 12 through a flange 12a. The bolt is automatically removed, and the lid 12 is lifted and removed by a crane (not shown), thereby opening the passage 8 side of the overpack 11. In addition, a steel reservoir (canister) 3 in which a radioactive substance (spent fuel, high-level radioactive waste, or the like) 13 is stored and sealed can be stored. Note that a cover is attached to the lid 12 as necessary. Seawater introduction tanks 14 and 14 are formed on the bottom and outside of the storages 9 and 9 as shown in FIGS.
Ballast tanks 15, 15 are formed outside the seawater introduction tanks 14, 14. This ballast tank 1
Circulating channels 16, 17 for circulating the seawater in the seawater introduction tanks 14, 14 and the external seawater are provided at the upper and lower portions of the seawater 5, 15 respectively.
Are formed. A lifter 18 is provided in the passage 8 between the storages 9 and 9 so as to be movable in two directions, up and down and horizontal, and a steel storage container (canister) 3 is provided at an upper end of the passage 8.
A loading / unloading path 19 is provided to protrude upward, and a loading / unloading port 21 of a transport cask 20 for storing and transporting the steel storage container (canister) 3 is provided on a side surface of the projection. A shutter type door or a double door 22 is provided. The door or the door 22 is provided with watertightness to prevent rainwater and waves from entering in order to prevent the passage 8 from being submerged in the event of a storm. The transport cask 20 is mounted on a trailer 23, the lid 24 is opened, and the telescopic arm 2 of the canister loading machine 25 is opened.
6, the steel storage container (canister) 3 in the transport cask 20 is taken in and out. The lid 24 is attached to the cask main body with bolts. The transport cask 20 can be opened by automatically removing the bolts and lifting and removing the lid 24 with a crane (not shown).

In the radioactive material storage facility 2 of the embodiment configured as described above, the radioactive material 13 such as spent fuel or high-level radioactive waste generated from the nuclear power plant 1 shown in FIG. The steel storage container (canister) 3 is stored in the transport cask 20 on the trailer 23, the lid 24 is closed, and the trailer 23 travels to carry the bridge 7 to the floating storage facility 2. , Stops in front of the carry-in / out entrance 21 of the transport cask 20. Next, the door or door 22 of the entrance 21 is opened,
As shown in FIG. 2, the trailer 23 is run and placed on the lifter 18 that has been waiting at a predetermined level position in the carry-in / out path 19 in advance, and the door 22 of the carry-in / out entrance 21 is closed. Next, the lifter 18 descends to the passage 8 between the storages 9, 9,
The lifter 18 is moved vertically and horizontally in the passage 8 and stops in front of the required storage shelf 10. After that, FIG.
After opening the lid 12 of the overpack 11 of the storage shelf 10 and the lid 24 of the cask 20 for transportation shown in FIG.
The steel storage container (canister) 3 in the transport cask 20 is pushed out by the extension of the telescopic arm 26 of the canister loading machine 25 shown in (1) and stored in the overpack 11 of the storage shelf 10, and the lid 12 is closed. In this way, the steel storage container (canister) 3 stored in the overpack 11 of the storage shelf 10 is heat-removed because the outside of the overpack 11 is water-cooled with pure water. And since the steel storage container (canister) 3 does not come into direct contact with seawater,
It does not corrode, and the stored radioactive material 13 such as spent fuel or high-level radioactive waste does not leak into seawater. Pure water whose temperature has risen by water-cooling the outside of the overpack 11 is radiated to the seawater in the seawater introduction tanks 14, 14, and the seawater in the seawater introduction tanks 14, 14 passes through the circulation passages 16, 17 and is supplied to the outside seawater. It circulates by natural convection, so it does not rise in temperature and is radiated to external seawater.
Thus, the radioactive substance 13 such as the spent fuel or high-level radioactive waste shown in FIG. 4 in the steel storage container (canister) 3 is cooled by natural convection of seawater. FIG.
When the steel storage container (canister) 3 is stored in the storage shelf 10 of the storage 9 on the left side in FIG.
Is mounted on the lifter 18 by running in the opposite direction.

In the storage facility 2, the storage shelves 10
Although pure water 12 is filled around the overpack 11 and heat is radiated to the seawater through the pure water, seawater may be introduced directly around the overpack 11 to radiate heat. In addition, when storing a steel storage container (canister) 3 in which a radioactive substance 13 such as a spent fuel or a high-level radioactive waste that generates a small amount of heat is stored and sealed, a cooling method is used instead of pure water in accordance with the heat removal amount. Air may be used, and this air may be replaced with external air by natural convection.

However, as in the above embodiment, the storage facility 2
Is a floating type floating on the sea, so that seawater can be used as a coolant, and the radioactive material 13 such as spent fuel or high-level radioactive waste shown in FIG. 4 is efficiently cooled. The storage capacity of the steel storage container (canister) 3 can be increased. Further, since cooling is performed by natural convection of seawater, a dynamic device such as a pump is not required, and safety is high and maintenance is easy. In addition, since the effect of the earthquake is small on the sea, a high storage facility 2 can be constructed,
The storage 9 is multi-layered, and the storage density is increased. In addition, since the transport cask 20 that has transported the steel storage container (canister) 3 is moved in the storage facility 2 using the lifter 18 that can move vertically and horizontally, the steel storage container (canister) 3 is used. 3 multilayer storage is realized. Further, since the storage facility 2 is constructed by utilizing the sea surface extending near the nuclear power plant 1, there is no need to secure a site for constructing the storage facility 2, and the storage facility 2 is further surrounded by mountains and hills. There is no need to take measures such as constructing the building in a location or covering the surroundings with embankment. Further, by constructing the storage facility 2 at a shipyard or the like and towing the storage facility 2 in the sea area near the nuclear power plant 1, the amount of local construction can be significantly reduced. In addition, since the shielding of the radioactive substance 13 can be performed by the surrounding seawater, the wall thickness of the floating storage facility 2 may be set to a thickness necessary for structural strength.
There is no need to increase the wall thickness more than necessary.

[0011]

As can be understood from the above description, the radioactive material storage facility of the present invention can use seawater as a coolant, and can efficiently cool the radioactive material.
The storage capacity of the steel storage container can be increased. In addition, since cooling is performed by natural convection of seawater or natural convection of air, safety is high and maintenance is easy. Also,
Since the effect of the earthquake is small, the storage can be multi-layered and the storage density can be increased. Further, multilayer storage of a steel storage container is realized by a lifter that can be moved in two directions, up and down and horizontally. In addition, there is no need to secure a site for the construction of a storage facility, and there is no need to specify a construction site, as long as it is in the sea area near the nuclear power plant. The required thickness may be used, and there is no need to increase the wall thickness more than necessary.

[Brief description of the drawings]

FIG. 1 is a schematic longitudinal sectional view showing one embodiment of a radioactive substance storage facility of the present invention.

FIG. 2 is an enlarged vertical sectional view of the storage facility of FIG. 1;

FIG. 3 is a vertical sectional view taken along line AA of FIG. 2;

FIG. 4 is an enlarged vertical sectional side view of an overpack of a storage shelf in the storage facility of FIG. 3;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Nuclear power plant 2 Storage facility 3 Steel storage container 4 Onshore 7 Bridge 8 Passage 9 Storage 10 Storage shelf 11 Overpack 14 Seawater introduction tank 16, 17 Seawater circulation channel 18 Lifter 20 Transport cask

Claims (6)

[Claims] 1. A floating-type storage container for horizontally storing a steel storage container sealed with radioactive materials generated from a nuclear power plant, which floats on the sea surface, and the periphery of the storage device is a natural convection of seawater or air. A storage facility for radioactive material, characterized in that it is configured to cool radioactive material. 2. The radioactive substance storage facility according to claim 1, wherein the floating type storage is configured to store the steel storage containers in a vertically stacked manner. Storage facility. 3. The radioactive material storage facility according to claim 1, wherein the transport cask transporting the steel storage container from the nuclear power plant is moved vertically and horizontally in two directions in the passage of the floating type storage. A storage facility for radioactive materials, comprising a lifter that can be moved to the area. 4. The radioactive material storage facility according to claim 1, wherein the steel storage container is filled with one of helium gas, nitrogen gas, and air disposed in a floating storage. A storage facility for radioactive materials, wherein the facility is stored in a pack. 5. The radioactive material storage facility according to claim 4, wherein one of pure water, seawater, and air is filled around the overpack in the storage. . 6. The radioactive substance storage facility according to claim 1, wherein a floating storage is connected to the land by a bridge.