JPH0314711B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a support structure that can immediately detect leakage of liquid in a tank from its bottom plate and can safely and reliably support the bottom plate.

[Technical background of the invention and its problems]

For example, laundry waste liquid from washing work clothes and the like used within a nuclear power plant is stored in a laundry waste liquid tank provided within the power plant. Conventionally, such tanks have been installed so as to be directly supported on a concrete foundation surface. However, in such a conventional support structure, a crack occurs in the bottom plate of the tank, and when laundry waste liquid containing radioactive substances flows out from the crack, the waste liquid soaks into the concrete foundation surface to some extent. And it is difficult to predict where it will leak out next. Therefore, there is a possibility that it will take a relatively long time until leakage of waste liquid is discovered. In addition, the bottom plate of a large tank is made by welding a plurality of plate materials, but the welding causes distortion in the bottom part. The center is often a slightly raised bottom plate. In that case, a space will be created between the concrete foundation surface and the lower surface of the bottom plate, and the center of the bottom plate will not be supported. Then, when waste liquid or the like is stored in the tank, the bottom surface is deformed by the water pressure of the waste liquid. Then, the bottom surface would move up and down depending on the amount of waste liquid, and there was a risk that the bottom surface would be fatigued and damaged.

[Purpose of the invention]

In view of the above problems, the present invention has been developed to easily and reliably detect liquid leakage from the bottom of a tank, and to detect all parts of the bottom even if there is a space between the bottom and the concrete foundation. To provide a support structure capable of supporting. Furthermore, the condition of the underside of the tank can be inspected.

[Means to solve the problem]

In the support structure of the present invention, a support plate 2 that does not absorb liquid is placed on a foundation concrete surface 1, and an annular support 3 is placed on the support plate 2. After the annular support 3 is completed, the peripheral edge of the lower surface of the tank is removably placed on the support 3. At the same time, the space between the tank bottom surface, the receiving plate 2, and the annular support 3 is filled with sand 5 for supporting the tank bottom surface. The tank is constructed so that it can be separated from the receiving plate 2 so that the tank can be lifted up as a whole after installation and the underside of the tank can be inspected. In addition to the above configuration, the detection head of the leak detection device 6 is located within the sand 5 or on the receiving plate 2, or is provided in communication therewith. Therefore, the entire bottom surface of the tank is supported by the filled sand 5. In addition, waste liquid and the like leaking from the bottom of the tank are reliably caught by the receiving plate 2, and the receiving plate 2 can reliably detect leakage from the tank by means of a leak detection device 6 provided within the sand 5 or the like.

[Embodiments of the invention]

Next, one embodiment of the present invention will be described based on the drawings. FIG. 1 is a vertical cross-sectional elevational view of a tank having a support structure according to the present invention. As shown in the figure, in the support structure of the present invention, first, a dish-shaped receiving plate 2 made of a steel plate or the like that does not absorb liquid is placed on a foundation concrete surface 1. Then, the grout material is molded and solidified in an annular shape along the periphery inside the receiving plate 2 to form the annular support 3. When drilling, the drain pipe 7 is passed through the rising part of the receiving plate 2 and penetrated into the grout material, and the anchor bolt 8 is fixed in advance through the foundation concrete surface 1, the receiving plate 2, and the annular support 3. I'll keep it. The bottom plate 9 of the tank 4 is then placed on the sand 5 and the annular support 3, and the tank 4 is constructed.
In addition, when the bottom plate 9 is formed by welding a plurality of plate materials, if distortion occurs in the bottom plate 9, holes are drilled at several places in the bottom plate 9, and new sand is filled through the holes.
The hole may be closed. Alternatively, as shown in FIG. 2, a horizontal hole is bored in the annular support 3, and a supply pipe 10 for sand filling is inserted into the horizontal hole. And the supply pipe 1
0 to a conventionally known sound blast device. That is, the compressor 12 applies pressure to the baked sand in the hopper 13 and supplies it to the filling gun 11. At the same time, compressed air is combined with the filling gun 11 to fill the space under the bottom plate with sand together with the compressed air. Next, connect the other end of the drain pipe 7, one end of which is disposed on the receiving plate 2, to the drain pot 14.
lead to. A detection head of a leak detection device 6 is provided within the drain pot 14. It should be noted that the present invention is of course not limited to the above-mentioned embodiment, and for example, the detection head of the leakage detection device 6 may be provided directly on the receiving plate 2 or may be provided within the sand 5. Further, the receiving plate 2 may be provided slightly inclined toward the drain pipe 7 side. Thereby, leaked waste liquid can be guided to the drain pipe 7 quickly and reliably.
At the same time, it is possible to prevent liquid from accumulating on the receiving plate 2.

[Action of invention. effect〕

The tank support structure of the present invention has the above configuration and has the following functions and effects.

In particular, in the support structure of the present invention, after the annular support 3 is completed, the peripheral edge of the bottom surface of the tank is removably placed on the support 3, and the tank can be lifted up as a whole after installation to inspect the bottom surface of the tank. Since the tank and the receiving plate are constructed separately, it is possible to check the corrosion state of the underside of the tank as needed, and this has the effect of preventing liquid leakage. Furthermore, in the support structure of the present invention, sand 5 is filled between the bottom plate 9 of the tank and the foundation concrete surface 1 with a receiving plate 2 interposed therebetween. Therefore, even if the bottom plate 9 is not flat at all, the entire tank bottom can be supported by the filled sand 5. Therefore, the bottom plate 9 is hardly deformed by the liquid contained in the tank. Therefore, it is possible to prevent cracks from occurring in the bottom plate 9 due to the deformation. In addition, since the receiving plate 2 does not absorb liquid, liquid leaking from cracks in the bottom plate 9, etc. will be absorbed by the receiving plate 2.
It can be detected by the leak detection device 6. Therefore, it is possible to reliably detect leakage from the tank bottom plate and quickly deal with it. Further, the support structure of the present invention allows the receiving plate 2 to contain leaked liquid and prevent it from flowing outside. That is, with this support structure, the tank has a double bottom, which has the effect of preventing waste liquid containing radioactive substances from inadvertently leaking outside due to cracks in the bottom plate of the tank body.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional elevational view of the tank support structure of the present invention, and FIG. 2 is an explanatory view showing an example of filling the space between the receiving plate 2 and the bottom plate 9 with second 5. 1... Foundation concrete surface, 2... Receiving plate, 3...
...Annular support, 4...tank, 5...sand, 6...
Leak detection device, 7...Drain pipe, 8...Anchor bolt, 9...Bottom plate, 10...Supply pipe, 11...
Filling gun, 12... Compressor, 13... Hopper, 14... Drain pot, P... Pressure gauge.

Claims (1)

[Scope of Claims] 1. A receiving plate 2 placed on a foundation concrete surface 1 that does not absorb liquid, an annular support 3 placed on the receiving plate 2, and after completion of the supporting plate 3, 3, a tank 4 on which the peripheral edge of the tank lower surface is removably mounted, and sand 5 for supporting the tank lower surface filled in a space between the tank lower surface, the receiving plate 2, and the annular support 3; 1. A support structure for a tank, characterized in that it can be separated from a receiving plate 2 so that the bottom surface of the tank can be inspected by lifting the entire structure after installation. 2. The structure according to claim 1, comprising a leakage detection device 6 for tank liquid, which has a detection head located within the sand 5 or on the receiving plate 2, or in a position communicating therewith.