JPH0444958B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to cask storage equipment.

At a nuclear power plant, spent nuclear fuel is removed from the reactor and loaded into a transport container called a cask, which is then stored in an on-site storage facility for one hour until it is transported.
Stored for a period of time. This cask can radiate heat generated from the spent nuclear fuel loaded inside into the atmosphere through its surface or fins protruding from it, and can also shield radiation from the spent nuclear fuel. Their weight ranges from several tens of tons to a hundred tons.

An example of conventional cask storage equipment is shown in Fig. 1, in which 01 is a cask, 02 is a trailer, 03 is a lifting device, 04 is a crane, 05 is a crane rail, 06 is a wall, and 07 is a ceiling. , 08 indicates the exhaust port, 09 indicates the intake port, and 010 indicates the ground. Since this storage facility requires a radiation shielding function, the walls 06 and ceiling 07 are made of concrete, and the thickness (d) is several times the thickness required for the strength of the structure. The thickness is, for example, 50 cm or more. In order to cool the heat radiated from the surface of cask 01 by natural convection, the height (H) of ceiling 07 is normally set.
Since the length is 20m or more, the amount of concrete used and the amount of reinforcing bars and steel frames to support it are large, which not only increases the construction cost but also increases the need for the crane 04 on the ceiling 07.
is constantly exposed to hot air from cask 01,
There was a problem with the electrical equipment having a short lifespan.

The present invention was invented to solve the above problems, and its gist is that the floor of the building is formed below the ground, and the cask storage room located at a lower level than the ground is A downward air path extending from the ground to the floor of the storage room is formed between a shielding side wall that is formed above the floor surface and surrounds the storage room and the outermost wall of the floor of the building, and is surrounded by the shielding side wall. an upper shielding wall with different levels is disposed above the storage room in which the air passes through, defining a zigzag passage for air; a tower is provided above the upper shielding wall; and the downward air passage through which a density flow of air flows; The cask storage facility is characterized in that the zigzag passage and the tower cooperate to form a thermosyphon passage.

In the present invention, an upper shielding wall is provided at the top of the cask storage room, which can shield the radiation emitted from the cask. Since there is no need to shield radiation, the exhaust tower above the upper shielding wall can be constructed of lightweight and inexpensive materials such as steel frames, iron plates, and slate.

This upper shielding wall was made at different levels to limit the zigzag air path of the air that passes around the cask and rises due to natural convection, so that the air that cools the cask can be powered by natural convection. It can be flowed through without any problem.

In addition, in the present invention, the cask is mounted on a trolley and transported to the cask storage room, so there is no need for an overhead crane as in the past, and the electric components of the overhead crane are exposed to hot air, which shortens their lifespan. Nor.

Hereinafter, the present invention will be specifically explained with reference to an embodiment shown in FIGS. 2 to 5.

Figure 2 is a schematic cross-sectional view showing the cask storage room, where 1 is the floor, 4 is the side wall, and 3a and 3b are the upper shielding walls, which not only function as strength members of the building but also shield from radiation. The cask storage room 20 is made of concrete and has a required wall thickness, forming a semi-underground cask storage room 20. 2 is steel frame, steel plate,
It is a lightweight tower made of slate or the like, and a ceiling opening 19 is provided at the top. Outside air is introduced through the louver 17 of the outside air intake port 6 and passes through the air passage 7 to the cask 10 installed in the cask storage room 20.
The air rises around the air, passes through a zigzag maze-like air path formed by upper shielding walls 3a and 3b arranged at different levels, and is discharged from the ceiling opening 19 of the tower building 2.

The cask 10 is transported to the cask loading chamber 2 by a trailer 15 as shown in FIGS. 4 and 5.
5 onto the floor 16, where it is lifted down by the overhead crane 14 and transferred via the hatch 24 onto the parent-child type carts 8 and 9. The parent truck 9 travels on the rails 13 and is transported to the cask storage room 20 on the left side of FIG. As shown in FIG. 2, the parent truck 9 stops in front of each storage room 20, and the child truck 8 riding on the parent truck 9 moves in a direction perpendicular to the moving direction of the parent truck 9. It is designed to move and advance into the storage room 20. This child truck 8 is provided with a lifter 8a that can push up the cask 10 through the pallet 11.
After the child truck 8 has advanced to a predetermined position, when the lifter 8a is lowered as shown in FIG.
is supported by the pallet 11 and the pallet receiver 22a extending from the floor 22. In this state, the child truck 8 passes under the pallet 11 and returns to the parent truck 9. Under the pallet 11 is the child truck 8.
A rail 12 and an inlet air passage 7 are installed. When the surface of the cask 10 is hot, the air around it is warmed and expands, creating buoyancy. This hot air rises as shown by the arrow and exits into the atmosphere through the upper opening 19.

Since the cask storage chamber 20 is surrounded by a thick side wall 4 and upper shielding walls 3a and 3b, radiation leakage to the outside can be prevented. Since the upper shielding walls 3a and 3b are arranged at different levels, it is possible to limit the zigzag natural convection air path for cooling the cask 10 while blocking radiation emission.
By providing the upper shielding walls 3a and 3b directly above the cask 10, there is no need to consider radiation shielding above them, and a lightweight and inexpensive structure such as a steel frame or slate is sufficient. Since the upper part of the cask storage room 20 is made into an exhaust tower and the parent and child carts 8 and 9 are used to transfer the cask 10 to the storage room 20 from a horizontal direction, the overhead crane 14 is exposed to hot air from the cask 10. There will be no more
Eliminates adverse thermal effects on electrical components, etc.

Furthermore, by forming the cask storage room 20 under the ground 18, the soil itself also functions as a radiation shield, so the side wall 4 located underground does not need to shield radiation by itself. , the wall thickness can be reduced, and the height required to obtain the required thermal draft, that is, the height of the tower 2 can be reduced. Furthermore, the height of the overhead crane 14 is sufficient to suspend the cask 10.

[Brief explanation of drawings]

FIG. 1 is a schematic sectional view showing one example of conventional cask storage equipment, and FIGS.
2 is an abbreviated sectional view showing a cask storage room, FIG. 3 is a sectional view taken along the line - in FIG. 2, and FIG. 4 is a schematic sectional view showing a cask loading room. FIG. 5 is a partially cutaway perspective view. Cask...10, Cask storage room...20,
Upper shielding wall...3a, 3b, trolley...8,9.

Claims (1)

[Claims] 1 The floor of the building is formed below the ground, and a cask storage room located lower than the ground is formed above the floor, between a shielding side wall surrounding the storage room and the outermost wall of the floor of the building. A downward air passage extending from the ground to the bottom of the storage room is formed, and an upper shielding wall with different levels is arranged above the storage room surrounded by the shielding side wall to define a zigzag air passage. , a cask storage characterized in that a tower is provided above the upper shielding wall, and the downward air passage through which the density flow of air flows, the zigzag passage and the tower cooperate to form a thermosyphon passage. Facility.