JPH04309890A - Repair of inner surface of fluid accommodation device - Google Patents

Abstract

PURPOSE:To obtain a repairing method for the inner surface of an accommodation device for radioactive fluid with which the work can be carried out in simple manner in a short time, only a necessary min. quantity of tools are used, and the danger of exposure is reduced. CONSTITUTION:A thin plate 6 is attached by an adhesive on a plate to be repaired on a metal plate 3 which constitutes the inner surface of a fluid accommodation device. The place to be repaired consists of the butt welded part 4 of the metal plate, cock welded part 5, and the metal plate 3 itself, and the adhesive is made of the two-liquid type silicone rubber, hardening type epoxi resin, etc., and when the thickness of the metal plate 3 is T, the min. width of the adhesion-covered region of the plate 6a is 3T-10T.

Description

[Detailed description of the invention]

0001

[Industrial Field of Application] The present invention relates to a method for repairing the inner surface of a fluid storage device, and more particularly, to a method for repairing the inner surface of a fluid storage device, and more particularly to a lining tank used in a pool of a nuclear power plant or a nuclear fuel reprocessing facility.
The present invention also relates to a method for repairing pinholes and cracks in welded parts of metal plates that constitute the inner surface of devices for flowing or storing fluids, and in the metal plates themselves.

0002

[Prior Art] As is well known, lined tanks used in pools of nuclear power plants and nuclear fuel reprocessing facilities, such as spent fuel pools, fuel handling pools, radioactive waste treatment and storage pools, and other vessels for flowing and storing fluids. The inner surface of the storage tank, etc. that is used to store the water is made of metal plates.

By the way, as the lining tank and the like are used over time, pinholes or cracks may occur in the butt-welded parts or plug-welded parts of the metal plates, or in the metal plates themselves. Defects are likely to occur in the welded portions of the butt welds and plug welds, depending on conditions such as temperature, humidity, material, etc. at the time of welding.

[0004] Conventionally, these repair methods have involved cleaning the area around where pinholes or cracks have occurred, scraping off defects such as pinholes or cracks using a manual grinder, and then performing repair welding or replacing the metal plate itself. It was something.

[0005]

According to the above-mentioned prior art, defective parts such as pinholes and cracks are removed and the removed parts are welded to repair them in the same way as normal welded parts.

[0006] However, the metal plate itself and the welding area are installed in the equipment, and if a tool such as a manual grinder is used or welding is performed there, the working time tends to be long. Furthermore, the working environment is often a radiation-controlled area, and although safety is considered, there is a problem in that there is a risk of exposure to radioactivity if the worker stays there for a long time.

[0007] Furthermore, since it is a radiation-controlled area, the time spent in the area is limited, and it requires skill to work with tools limited to the minimum necessary, and furthermore, the qualifications of welders are limited by law. Therefore, there was a problem that it was difficult to secure personnel.

[0008]

[Objective] Therefore, the object of the present invention is to make the work simple, quick, require minimal tools, reduce the risk of radiation exposure, and require no skill to perform the work. The present invention provides a method for more completely repairing the inner surface of a fluid containing device.

[0009]

[Means for Solving the Problems] In order to achieve the above object, the present invention has the following technical means. That is, to explain this using the reference numerals in the attached drawings corresponding to the embodiments, the present invention provides a method for repairing a metal plate constituting the inner surface of a fluid containing device. The thin plate 6 is bonded to the area to be repaired using an adhesive 7, and the minimum width of the area where the thin plate 6 is adhesively covered is from 3T to 10T, where T is the thickness of the metal plate 3. This is a method for repairing the inner surface of a fluid containing device.

0010

[Operation] Based on the above configuration, this repair method
Since the thin plate 6 is simply glued to the area to be repaired with the adhesive 7, the work is easy, and the worker only needs to bring the thin plate 6 and the adhesive 7, and the work can be completed in a short time. be.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In an embodiment of the present invention, the fluid containing device is a lined tank. As shown in FIG. 1, the lining tank has a concrete layer 1, inside which a metal plate 3 is attached and supported by a backing metal 2 on the concrete 1. Furthermore, since the interior of the lining tank cannot be constructed from a single metal plate, it is constructed from a plurality of metal plates 3. Therefore,
One metal plate 3a and the other metal plate 3b are connected by butt welding. Furthermore, plug welding 5 is applied to the metal plate 3 as required. Note that the metal plate 3 is made of iron-based metal.

[0013] If the above-mentioned lining tank is used for a long period of time, defects such as cracks and pinholes will occur. In particular, the strength of the butt weld 4 and the plug weld 5 varies depending on the conditions such as temperature and humidity when welding, and defects are likely to occur and cracks and pinholes may occur. Furthermore, defects may occur in the metal plate 3 itself.

[0014] Then, a thin plate 6 is bonded to the defective portion 8 using an adhesive 7 to repair it. The thin plate 6 is a thin metal plate such as stainless steel, titanium, or aluminum, or a thin resin plate such as acrylic, glass fiber, or vinyl chloride, and the adhesive 7 is a two-component silicone rubber type, hardening type epoxy resin, etc. An example of the adhesive 7 is one that hardens in 30 minutes at 30 degrees. Next, a specific example of the above repair method will be described.

As a specific example 1, a method for repairing the butt weld 4 will be described. First, it is assumed that a crack 8 has occurred in the butt weld 4, as shown in FIG. Therefore, a thin plate 6a is prepared which is press-formed to match the welded shape of the butt welded portion 4. Then, as shown in FIG. 3, adhesive 7 is uniformly applied to the back surface of the thin plate 6a. Next, as shown in FIG. 4, adhesion is performed, and the product is completed as shown in FIG. FIG. 6 is a cross-sectional view of FIG. 5, in which the minimum width of the thin plate 6a is eight times the thickness of the metal plate 3. Immediately after bonding, fluid is stored in the lining tank, and when water pressure is applied to the thin plate 6a, the adhesive 7 may be pushed into the crack 8 depending on the size of the crack 8.

Although the minimum width of the thin plate 6a in Example 1 was eight times the thickness of the metal plate 3, as described above, water pressure is applied to the thin plate 6 to push the adhesive 7 into the defective portion 8. For this reason, it is preferable that the minimum width of the thin plate 6 is 3 to 10 times the thickness of the metal plate 3.

Next, as a second specific example, a method for repairing the plug weld 5 will be described. First, as shown in FIG. 7, a pinhole 8 is formed in the plug welded portion 5. Therefore, a thin plate 6b that is pressed to match the welded shape of the plug welded portion 5 is prepared. Then, as shown in FIG. 8, adhesive 7 is uniformly applied to the back surface of the thin plate 6b. Next, as shown in FIG. 9, adhesion is performed, and the repair is completed as shown in FIG.

Note that the metal plate 3 is not a welded part as described above.
In some cases, cracks or pinholes may be formed in the thin plate 6, in which case the thin plate 6 is bonded while remaining flat.

Further, although the shape of the thin plate 6 is rectangular in the first embodiment and circular in the second embodiment, various other shapes are conceivable that can repair the defective portion 8 more reliably.

Further, although the adhesive 7 is applied to the back surface of the thin plate 6, it can also be applied to the metal plate 3 side. In this case, it is necessary to tape the area other than the area where the thin plate 6 is to be adhesively coated.

As described above, the above repair method uses the thin plate 6 and adhesive 7 and does not involve welding, so there is no need to bring in large tools such as a welder, and there is no need to use open flames. It can be used in a working environment and does not cause new defects due to welding heat. Furthermore, in the event that a large crack or multiple defective parts in close proximity occur, a large area can be repaired all at once. Furthermore, since the work is simple and can be completed in a short time, there is less risk of radiation exposure. When the fluid is contained after the repair, the thin plate 6 receives water pressure, and since the adhesive 7 has elastic recovery properties, the adhesive 7 comes into pressure contact with the defective part 8 and seals it, making it more firmly bonded and completing the repair more completely. This is the result.

[0022]

Effects of the Invention As detailed above, claims 1, 2, 3, and 4
According to the invention, the work is simple, can be done in a short time, requires a minimum number of tools, has less risk of radiation exposure, and has the advantage that defective parts can be repaired more completely. Furthermore, the lamellae are bonded to the inner surface of the fluid containment device with an adhesive so that during use, the pressure of the fluid pushes the lamina closer together, resulting in a better seal.

Further, according to the fifth aspect of the invention, since the adhesive has elastic recovery properties, the adhesive layer is compacted when fluid is contained after repair, but it is restored to its original state when the fluid is subsequently removed. Since it is prevented from forming a hard plate-like layer regardless of whether water is present, it is highly durable for repeated use, and the invention according to claim 6 According to the above, although the adhesive layer does not have elastic recovery properties, in this case, large water pressure is not applied to the upper part of the fluid containing device in the direction of gravity, so it is effective for repairing areas where such large water pressure is not applied. .

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of a fluid storage device.

FIG. 2 is a diagram showing a procedure for repairing a butt welded portion.

FIG. 3 is a diagram showing a procedure for repairing a butt welded portion.

FIG. 4 is a diagram showing a procedure for repairing a butt welded portion.

FIG. 5 is a diagram showing a procedure for repairing a butt welded portion.

6 is a sectional view taken along line XX in FIG. 5. FIG.

FIG. 7 is a diagram showing a procedure for repairing a plug welded portion.

FIG. 8 is a diagram showing a procedure for repairing a plug welded portion.

FIG. 9 is a diagram showing a procedure for repairing a plug welded portion.

FIG. 10 is a diagram showing a procedure for repairing a plug welded portion.

[Explanation of symbols]

1. Concrete 2. Back deposit 3. Metal plate 4. Butt welding part 5. Plug welding part 6. Thin plate 7. Adhesive 8. Defect part

Claims (6)

[Claims] 1. In a method of repairing a metal plate constituting the inner surface of a fluid containing device, the repair method includes bonding a thin plate 6 to a portion of the metal plate 3 to be repaired with an adhesive 7, and A method for repairing an inner surface of a fluid containing device, characterized in that, where T is the wall thickness of the plate 3, the minimum width of the area where the thin plate 6 is adhesively coated is from 3T to 10T. [Claim 2] The area to be repaired is one metal plate 3.
2. The method of repairing an inner surface of a fluid containing device according to claim 1, wherein the portion 4 is a portion 4 where the metal plate 3a and the other metal plate 3b are butt welded. 3. The method of repairing an inner surface of a fluid containing device according to claim 1, wherein the location to be repaired is a plug welded location 5. 4. The method for repairing an inner surface of a fluid storage device according to claim 1, wherein the portion to be repaired is the metal plate 3 itself. 5. The adhesive 7 is a two-component silicone rubber-based adhesive that has elastic recovery properties after hardening. Repair method. 6. The method for repairing the inner surface of a fluid containing device according to claim 1, wherein the adhesive 7 is a hardening type epoxy resin.