Used nuclear fuel storage facility and spacer member used for the facility

Abstract

To provide a used nuclear fuel storage facility and a used nuclear fuel storage method such that even if an earthquake, etc., take place at a facility where used fuel storage containers are laid horizontally and stored, the storage containers never collide against each other.SOLUTION: A used nuclear fuel storage facility comprise: storage containers which store used nuclear fuel; a support frame on which the storage container is mounted; a transport vehicle travel groove where the transport vehicle having the storage container mounted on the support frame can travel; a support frame bearing part which is provided at an edge of the transport vehicle travel groove and bears at least a part of the support frame; and a spacer member which is long enough to maintain a distance at which storage containers mounted on support frames do not come into contact with each other in a length direction of the storage containers.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a storage facility for storing spent fuel storage containers, and more particularly to a storage facility for storing spent nuclear fuel storage containers in a horizontal position, and a spacer member used in the facility. [Background technology]

[0002] Spent nuclear fuel assemblies generated at nuclear power plants are stored in dedicated storage containers and transported to storage facilities for storage. The mainstream storage method is dry storage, which does not use water or electricity, but cools the storage container by natural convection generated by heat emitted from the spent fuel storage container. The present invention relates to a spent nuclear fuel storage facility that employs dry storage, but in the following explanation, the term "dry" will be omitted.

[0003] Storage containers are generally transported horizontally to reduce the risk of tipping over when transporting them from the reactor building to the storage facility. Conventional storage facilities mainly use a method in which storage containers that have been transported horizontally are erected and stored vertically.

[0004] While vertical storage has the advantage of being able to store a greater number of items per unit area, it has the drawback that storage containers that have been transported horizontally must be erected by a crane and moved to the designated location, necessitating the installation of a crane in the storage building, which results in the storage facility becoming larger.

[0005] To solve this problem, Patent Document 1 discloses a horizontal-laying storage building and storage method in which a platform for erecting storage containers is placed on the platform of a cart, the storage containers are placed on the platform and transported, the cart is moved to the storage facility, and at a specified position, a lifting function of the platform is used to lower the platform onto the floor of the storage facility for storage. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2003-75584 A Summary of the Invention [Problem to be solved by the invention]

[0007] In the horizontal storage facility described in Patent Document 1, spent nuclear fuel storage containers are installed along the transport vehicle path, so when storing multiple containers, the containers are placed in a long facility such as a tunnel with the lid and bottom facing each other. With this placement method, there is a concern that in the event of an earthquake or other disaster, the support racks for the placed storage containers may slide along the transport vehicle path, causing the storage containers placed on the support racks to collide with each other. In nuclear facilities where safety is the top priority, it is necessary to avoid compromising the containment function of the storage containers due to collisions.

[0008] The object of the present invention is to provide a spent nuclear fuel storage facility that stores spent nuclear fuel storage containers horizontally and that can prevent the storage containers from colliding with each other even if an earthquake or the like occurs, and a spacer member for use in the facility. [Means for solving the problem]

[0009] The present invention has the following configuration for solving the above-mentioned problems.

[0010] A spent nuclear fuel storage facility comprising: a storage container for storing spent nuclear fuel; a support stand on which the storage container is placed; a transport vehicle running groove along which a transport vehicle carrying the storage container on the support stand can run; a support stand receiving portion provided on the edge of the transport vehicle running groove for receiving at least a part of the support stand; and a spacer member having a length in the longitudinal direction of the storage container that maintains a distance such that the storage containers placed on the support stand do not come into contact with each other. Effect of the Invention

[0011] The present invention makes it possible to provide a spent nuclear fuel storage facility that stores spent nuclear fuel storage containers horizontally and that can prevent the storage containers from colliding with each other even if an earthquake or the like occurs, and a spacer member for use in the facility. [Brief description of the drawings]

[0012] [Figure 1] Conceptual diagram of loading the storage container from the reactor building onto a transport vehicle [Diagram 2] Schematic diagram (side view) of transporting storage containers from the reactor building to the storage facility [Diagram 3] Conceptual diagram of transporting storage containers from the reactor building to the storage facility (top view) [Figure 4] Front view of a transport vehicle traveling within a storage facility [Diagram 5] FIG. 1 is a perspective view of a storage container placed on a storage facility using the spacer member according to the present invention; [Figure 6] FIG. 1 is a top view of a storage container placed on a storage facility using the spacer member according to the present invention; [Figure 7] FIG. 1 is a top view of a storage container placed on a storage facility using the spacer member according to the present invention; [Figure 8] FIG. 1 is a side view of a transport vehicle when transporting a storage container with the spacer member according to the present invention attached thereto from a reactor building to a storage facility. [Figure 9] FIG. 1 is a top view of a storage container placed on a storage facility using a spacer member formed by extending a portion of a support stand according to the present invention; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] After the spent nuclear fuel is loaded into the reactor building, storage containers for radioactive materials such as spent nuclear fuel are loaded sideways onto a storage container transport vehicle (cask trailer) at the large item entrance (see Figure 1). The reason for transporting the containers sideways is to reduce the risk of tipping over during transport, as the storage containers are heavy.

[0014] Figure 2 shows a side view of the transport vehicle used for transporting the spent nuclear fuel storage container from the reactor building to the storage facility. A support stand 3 is installed on the transport vehicle 1 so that the spent nuclear fuel storage container 2 can be supported sideways. The spent nuclear fuel storage container 2 is loaded sideways on the support stand 3 loaded on the transport vehicle 1.

[0015] The loading platform 11 of the transport vehicle 1 has a lifting and lowering function, and bolt holes are provided so that the support frame 3 can be fixed to the transport vehicle 1. In addition, the spent nuclear fuel storage containers 2 are fitted with shock absorbing buffers 5 to prevent the containers from being damaged even when the containers come into contact with each other. The buffers may be made of any elastic material, such as rubber, plastic, wood, flexible metal, resin, etc.

[0016] 3 is a top view of a transport vehicle used for transporting fuel from the reactor building to the storage facility. The transport vehicle 1 runs on roads within the nuclear power plant using wheels attached to the vehicle.

[0017] Fig. 4 shows a front view of a transport vehicle traveling within a storage facility. The storage facility 6 is composed of a transport vehicle running groove 7 (sometimes referred to as a vehicle running section), a support frame receiving section 8, and a shielding wall 9. Here, the width (a) of the support frame 3 is wider than the vehicle width (b) of the transport vehicle 1, and the height (c) of the support frame 3 from the running surface when traveling in the transport vehicle running groove 7 is higher than the height (d) of the support frame receiving section 8. EXAMPLES

[0018] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. However, the present invention is not limited to the embodiment.

[0019] FIG. 5 is a perspective view showing a state in which a storage container is placed on a storage facility using a substantially I-shaped steel material as the spacer member 4 according to the present invention.

[0020] If different spent nuclear fuel storage containers 2 are stored in contact with each other, there is a risk that the containers will be damaged by pushing against each other in the event of an earthquake, etc. In addition, as described below, a pressure gauge (not shown) is installed on the lid of the spent nuclear fuel storage container 2 to measure the internal pressure, and work using the pressure gauge on the lid is periodically carried out. It is necessary to install the spent nuclear fuel storage containers 2 apart from each other to ensure work space.

[0021] On the other hand, if the spent nuclear fuel storage containers are spaced apart, there is a risk that in the event of an earthquake or other disaster, the spent nuclear fuel storage containers 2 may shift sideways and come into contact with each other, resulting in damage. In addition, there is a possibility that the components related to the maintenance of the storage container, such as the pressure gauge, may be damaged.

[0022] By providing the spacer members 4 according to the present invention, even if a force that would cause the spent nuclear fuel storage containers 2 to shift laterally is applied during an earthquake, the horizontal stress acting on the support cradles 3 will cause the support cradles 3 to push against each other through the spacer members 4, thereby reducing the risk of the spent nuclear fuel storage containers 2 colliding with each other. In other words, since the compressive stress of the spacer members 4 is far greater than the horizontal stress due to an assumed earthquake, the possibility of the spacer members 4 being compressed and causing the spent nuclear fuel storage containers 2 to come into contact with each other is extremely low.

[0023] In addition, this configuration eliminates contact between the spent nuclear fuel storage containers 2, eliminating the need to attach the buffer 5 in the axial direction of the spent nuclear fuel storage containers 2. Alternatively, a smaller buffer will suffice. The I-shaped steel material in this embodiment may be made of solid material, but since solid material is heavy and difficult to handle and expensive, it may be manufactured by welding or the like using general steel materials such as H-shaped steel or square steel pipes.

[0024] The material and shape of the spacer member 4 can be designed in any way as long as the compressive stress of the spacer member 4 is greater than the horizontal stress caused by the expected earthquake. The shape of the surface of the spacer member 4 that comes into contact with the support frame 3 is preferably the same as the cross-sectional shape of the legs of the support frame, but it can also be a shape similar to the "combination of a mortise and tenon protrusion" used in woodworking. This shape has the added effect of preventing the storage container from shifting in the direction perpendicular to its long axis (the support frame receiving part 8 described below basically prevents the storage container from shifting in the direction perpendicular to its long axis, but if you want to minimize the amount of shift, it is worth choosing a shape similar to the "combination of a mortise and tenon protrusion").

[0025] The spent nuclear fuel storage container 2 generates heat as the stored spent nuclear fuel gradually undergoes nuclear decay. The storage container is equipped with a structure that transfers the generated heat to the outer surface and removes it from the outer surface, but there is a concern that the heat removal performance will decrease if the buffer body 5 is attached because of its large area.

[0026] Furthermore, a pressure gauge is installed on the lid of the spent nuclear fuel storage container 2 to measure the internal pressure. As the pressure gauge is required to be calibrated periodically, calibration work is expected to be performed on the lid. During calibration work, there is a concern that the attachment of the buffer body 5 may reduce access to the lid and workability. For the above reasons, it is desirable not to attach the buffer body 5 in the axial direction of the spent nuclear fuel storage container 2, but by providing the spacer member 4, it is possible to provide a facility configuration that does not interfere with the heat removal function of the spent nuclear fuel storage container 2 or the calibration work.

[0027] A plan view of the storage facility is shown in Figure 6. In the case of horizontal storage, since no crane is used, the spent nuclear fuel storage containers 2 are transported only in the direction of travel of the transport vehicle, so when multiple containers are stored in the storage facility 6, the facility configuration is long in the axial direction of the transport vehicle 1.

[0028] In the case of this facility configuration, if there are no spacer members 4, the support racks 3 on which the spent nuclear fuel storage containers 2 are placed may slide when an earthquake occurs, causing the spent nuclear fuel storage containers 2 to collide with each other. If the spent nuclear fuel storage containers 2 collide with each other and the lids are damaged, there is a possibility that the containment function, which is one of the safety functions of the spent nuclear fuel storage containers 2, may be lost. For this reason, the buffer bodies 5 attached to the spent nuclear fuel storage containers 2 are attached to the top and bottom, and are attached in the axial direction of the spent nuclear fuel storage containers 2.

[0029] The storage facility 6 is provided with a support frame receiving section 8, and after traveling through the storage facility 6, the transport vehicle 1 is released from the fastening of the support frame 3 and spacer member 4 at a specified storage position, the loading platform of the transport vehicle 1 is lowered, and the support frame 3 and spacer member 4 are installed on the support frame receiving section 8. At this time, since the support frame 3 and spacer member 4 are at the same height on the transport vehicle 1, when the support frame 3 is transferred to the support frame receiving section 8, the spacer member 4 is also transferred to the support frame receiving section 8 at the same time.

[0030] In addition, the support frame receiving portion 8 is shaped by carving out the edge of the transport vehicle running groove so that it is at a different height from the passageway 10, so that the spent nuclear fuel storage container 2 will not move laterally (in a direction perpendicular to the transport vehicle running groove) without being fixed in place, even in the event of an earthquake.

[0031] The second spent nuclear fuel storage container 2 is transported to the storage facility 6 using a similar method, and then the second support frame 3 is installed so as to be in contact with the spacer member 4 of the first container. In this case, the spacer members may be connected to each other, or may be installed with a gap between them. If the gap is too large, the storage containers may gain momentum in the event of an earthquake or the like and collide with each other. If there is a gap, it is preferable that the gap be about a few centimeters.

[0032] 7 shows a state in which the storage container to which the spacer members 4 are attached is being transported by a transport vehicle 1. The spacer members 4 can be transported by the transport vehicle 1 in a state in which they are attached to a support frame.

[0033] The spacer member 4 in Fig. 6 has an I-shape (or H-shape) when viewed from above. In terms of its function of simply maintaining a constant distance between storage containers, if it has a width large enough to rest on the support frame receiving parts 8 at the edge of the transport vehicle running groove 7, the risk of spent nuclear fuel storage containers 2 colliding with each other during an earthquake is reduced. However, the spacer member 4 needs to be transported loaded onto the transport vehicle 1 to the storage container storage site.

[0034] Since the width (b) of the transport vehicle is narrower than the width (a) of the support frame 3, in order to mount the spacer member 4 on the transport vehicle 1, a member that connects the two straight members and is wide enough to be placed on the support frame receiving portion 8 is required. Considering ease of manufacture, it is preferable that the spacer member 4 is I-shaped (or H-shaped) when viewed from above. However, as long as it can be mounted on a transport vehicle for transport, it does not have to be I-shaped or H-shaped.

[0035] For example, it may have a structure in which two straight members each having a width sufficient to rest on the support frame receiving portion 8 are connected by a plurality of straight members in a direction perpendicular to the straight line. In this case, the connecting straight members must have a strength sufficient to support the weight of the two straight members.

[0036] It may have a structure like an I-shape with a hollowed-out center as shown in Fig. 7. The member connecting two straight members wide enough to rest on the support stand receiving portion 8 is useful for an operator to stand on and work on, for example, the calibration work of the pressure gauge for measuring the pressure inside the storage container, so it is preferable that the upper surface of the member has a flat shape so that an operator can stand on it and work. EXAMPLES

[0037] In this embodiment, instead of using a spacer member 4 configured separately from the support member, an example is shown in which a portion of the support frame 3 placed on the support frame receiving portion 8, extended in the transport vehicle travel direction (the direction in which the vehicle travel groove extends) functions as the spacer member. Figure 8 shows a plan view of a storage facility using an extended support frame. When a separate spacer member 4 is not used, a facility configuration in which the spent nuclear fuel storage containers 2 do not come into contact with each other can be provided by using a support frame 3' in which the support frame 3 has been previously extended in the axial direction.

[0038] The spacer member of Example 1 has the characteristic that it can be applied to existing storage facilities where the shape and the like of the support stand 3 are fixed. In addition, by manufacturing it separately from the support stand 3, it is expected that the individual weight will be small and easy to handle. On the other hand, the configuration of Example 2 can be applied when a new support stand is made, and it is expected that ease of manufacturing will be achieved by manufacturing it as a single unit. [Explanation of symbols]

[0039] 1...transport vehicle, 2...spent nuclear fuel storage container, 3...support frame, 4...spacer member, 5...buffer, 6...storage facility, 7...transport vehicle running groove, 8...support frame receiving portion, 9...shielding wall, 10...passageway

Claims

1. a storage vessel for storing spent nuclear fuel; A support stand on which the storage container is placed; a transport vehicle running groove along which a transport vehicle carrying the storage container on the support frame can run; A support frame receiving portion provided on an edge portion of the transport vehicle running groove and receiving at least a part of the support frame; a spacer member having a length in a longitudinal direction of the storage containers such that the storage containers placed on the support stand are spaced apart from each other without contacting each other; A spent nuclear fuel storage facility comprising:

2. 2. The spent nuclear fuel storage facility according to claim 1, A spent nuclear fuel storage facility characterized in that the spacer member comprises two straight sections extending in a direction parallel to the transport vehicle running groove on top of the support frame receiving portions at both ends of the transport vehicle running groove, and a connecting portion connecting the two straight sections.

3. 3. The spent nuclear fuel storage facility according to claim 2, A spent nuclear fuel storage facility, characterized in that the two straight sections and the connecting section connecting the two straight sections are a single structure having an approximately I-shape when viewed from above the transport vehicle running groove.

4. 2. The spent nuclear fuel storage facility according to claim 1, A spent nuclear fuel storage facility characterized in that at least a portion of the support frame comprises a portion extending in a direction parallel to the transport vehicle running groove above the support frame receiving portion at both ends of the transport vehicle running groove.

5. The spacer member, which is used in the spent nuclear fuel storage facility according to any one of claims 1 to 4.

6. a storage vessel for storing spent nuclear fuel; A support stand on which the storage container is placed; A transport vehicle including a lifting mechanism for lifting and lowering the support frame; a transport vehicle running groove that is provided by being dug below the floor surface of a building, the transport vehicle being provided by being dug below the floor surface of the building, and the transport vehicle running on the transport vehicle; a placement area in which the width of the support frame in a direction substantially perpendicular to the transport vehicle running groove is wider than the width of the transport vehicle running groove, and an end of the support frame is placed on a support frame receiving part provided on an edge of the transport vehicle running groove and receiving at least a part of the support frame, so that the support frame is placed so as to cover the transport vehicle running groove; A spent nuclear fuel storage facility, comprising: placing the support frame on which the storage container is loaded onto a loading platform of the transport vehicle; raising the loading platform by the lifting mechanism so that the height of the support frame placed on the loading platform is higher than the floor surface; causing the transport vehicle to travel along the transport vehicle running groove to the placement area; lowering the loading platform in the placement area by the lifting mechanism; and placing ends of the support frame on both edges of the transport vehicle running groove, thereby moving the storage container to the placement area and storing the storage container in this placement area, A spent nuclear fuel storage facility characterized in that in the placement area, multiple storage containers are installed along the transport vehicle running groove with spacer members provided in the longitudinal direction of the storage containers, the spacer members having a length sufficient to maintain a distance such that the storage containers placed on the support frames do not come into contact with each other.

7. 7. The spent nuclear fuel storage facility according to claim 6, A spent nuclear fuel storage facility characterized in that the spacer member comprises two straight sections extending in a direction parallel to the transport vehicle running groove on top of the support frame receiving portions at both ends of the transport vehicle running groove, and a connecting portion connecting the two straight sections.

8. The spent nuclear fuel storage facility according to claim 7, A spent nuclear fuel storage facility, characterized in that the two straight sections and the connecting section connecting the two straight sections are a single structure having an approximately I-shape when viewed from above the transport vehicle running groove.

9. 7. The spent nuclear fuel storage facility according to claim 6, A spent nuclear fuel storage facility characterized in that at least a portion of the support frame comprises a portion extending in a direction parallel to the transport vehicle running groove above the support frame receiving portion at both ends of the transport vehicle running groove.

10. The spacer member, which is used in the spent nuclear fuel storage facility according to any one of claims 6 to 9.

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