Leakage stoppage method

Abstract

We provide leak-stopping technology that allows for the repair of tanks while the liquid remains stored inside. [Solution] The leak-stopping method includes the steps of: sandwiching a water-stopping member 15 with an excitation means at a position that seals the leak location 12 from the inside of the tank 11; exciting the excitation means to magnetize the tank; welding the periphery of the leak location and the water-stopping member from the outside of the tank; and demagnetizing the excitation means, separating it from the tank, and recovering it.

Description

Technical Field

[0001] Embodiments of the present invention relate to a leakage prevention technique for a tank storing a liquid.

Background Art

[0002] Radioactive contaminated water generated during the severe accident treatment of a nuclear reactor and staying within the nuclear reactor facility is stored in a steel tank after removing and purifying radionuclides.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Assuming that the purified water stored leaks due to the aging deterioration of this steel tank, leakage prevention measures are being considered. Generally, when a leakage of the tank is confirmed, after discharging the stored liquid, repair work for stopping the leakage at the leakage point is carried out. However, discharging or transferring the stored liquid reduces the efficiency of the repair work of the tank.

[0005] Embodiments of the present invention have been made in consideration of such circumstances, and an object thereof is to provide a leakage prevention technique for repairing a tank while storing a liquid.

Means for Solving the Problems

[0006] In the leakage prevention method according to the embodiment, a step of sandwiching a water stop member with excitation means at a position closing the leakage point from the inside of the tank, a step of exciting the excitation means to magnetize the tank, a step of welding the periphery of the leakage point and the water stop member from the outside of the tank, and a step of demagnetizing the excitation means and separating and recovering it from the tank are provided.

Effects of the Invention

[0007] Embodiments of the present invention provide a leak-stopping technology for repairing a tank while retaining liquid. [Brief explanation of the drawing]

[0008] [Figure 1] (A)(B)(C)(D) Explanatory diagrams of the steps of a leak-stopping device and a leak-stopping method according to an embodiment of the present invention. [Figure 2] (A)(B) A longitudinal cross-sectional view of a leak-stopping device according to the first embodiment. [Figure 3] (A)(B)(C)(D) Functional diagrams illustrating the support means for mechanically supporting the water-stopping member with the excitation means. [Figure 4] (A) A longitudinal cross-sectional view of a leak-stopping device according to the second embodiment, and (B) the same, a horizontal cross-sectional view. [Figure 5] (A)(B)(C) Functional diagrams of the sealing member according to the embodiment. [Figure 6] (A)(B)(C)(D) Explanatory diagrams of the steps of the leak-stopping device and leak-stopping method according to the third embodiment. [Modes for carrying out the invention]

[0009] Hereinafter, embodiments of the present invention will be described based on the attached drawings. Based on the ZX longitudinal cross-sectional view in Figures 1(A), 1(B), 1(C), and 1(D), the steps of the leak-stopping device 10 and the leak-stopping method according to the present invention will be described.

[0010] As shown in Figure 1(A), the leak-stopping device 10 includes an excitation means 20 that magnetizes the tank 11, which is made of a magnetic material, by sandwiching a water-stopping member 15 between the inside of the tank 11 at a position that seals the leak point 12. Here, the "sandwiched" aspect refers to the state in which the water-stopping member 15 is inserted into the gap formed between the inner surface of the tank 11 and the excitation means 20. The size of the gap formed between the inner surface of the tank 11 and the excitation means 20 is such that the gap is closed by magnetic force alone when the excitation means 20 is excited. Furthermore, there is no particular limitation on whether or not the water-stopping member 15 is in surface contact with this gap before excitation.

[0011] Furthermore, while the example given for tank 11 is the storage of purified water (liquid 16) from which radioactive nuclides have been removed from radioactive contaminated water, the liquid 16 to be stored is not particularly limited. Also, the material of tank 11 is generally iron or an iron alloy, but there is no particular limitation, and any material that can be magnetized by the excitation means 20 can be used as appropriate.

[0012] The leak point 12 is where liquid 16 leaks from the inside to the outside due to the aging deterioration of the tank 11. To prevent such leaks, repairs are carried out by sealing the leak point 12 from the inside of the tank 11 with a water-sealing member 15. The shape of this water-sealing member 15 is pre-processed so that it makes surface contact with the inner surface of the tank 11 where the leak point 12 is located.

[0013] In this embodiment, the repair of the side of the tank 11 is illustrated as an example, but there are no particular limitations on the location of the leak point 12 to be repaired. For example, the bottom surface or bottom edge of the tank 11 can also be repaired. Furthermore, there are no particular limitations on the shape of the tank 11, and any shape is applicable, including cylinders, rectangular parallelepipeds, cubes, etc. Regardless of the location of the repair on a tank of various shapes, the shape of the water-stopping member 15 is pre-processed so that it makes surface contact with the inner surface where the leak point 12 is located.

[0014] Furthermore, while the material of the water-sealing member 15 is generally the same as that of the tank 11, considering that it will be welded in a later process, there are no particular limitations. The material of the water-sealing member 15 does not particularly need to be magnetized by the excitation means 20, and may be an organic material (such as resin) or a composite material of organic and inorganic materials.

[0015] The excitation means 20 uses an electromagnet with a coil wound around it, and by turning the current ON / OFF, the generation of magnetic flux is turned ON / OFF, switching between excitation and demagnetization. In this way, the maintenance / demagnetization of the nearby tank 11 is also switched according to the external magnetic field generated by the excitation means 20. When the tank 11 is magnetized, a pressing force is applied to the water-stopping member 15 sandwiched between the excitation means 20. Although the excitation means 20 is exemplified as being an electromagnet, other means such as permanent magnets can be used as long as the maintenance / demagnetization of the nearby tank 11 can be switched.

[0016] Furthermore, if the material of the water-sealing member 15 is a material that can be magnetized by the excitation means 20 (for example, an iron plate), the water-sealing member 15 can also be magnetically attracted to the tank 11 by the excitation means 20, thereby making the adhesion of the water-sealing member 15 stronger. Also, if the material of the water-sealing member 15 is an elastic material such as rubber that cannot be magnetized by the excitation means 20, the attractive force will decrease, but the adhesion can be improved.

[0017] Next, the procedure for stopping the leak will be explained. As shown in Figure 1(A), the water-stopping member 15 and the excitation means 20 are added to the liquid 16 stored in the tank 11. Both methods of adding the two components are possible: adding them separately or combining them beforehand. Then, as shown in Figure 1(B), the leak point 12 in the tank 11 is sealed from the inside with the water-stopping member 15. Note that the water-stopping at the leak point 12 by the water-stopping member 15 does not need to be perfect; it is sufficient to stop the leak to the extent that subsequent repair work can be carried out.

[0018] Next, as shown in FIG. 1(C), excitation means 20 is arranged at a position sandwiching the water stop member 15 and excited to magnetize the tank 11. As a result, the water stop member 15 is brought into close contact at a position closing the leakage point 12. In this state, the peripheral edge of the leakage point 12 and the water stop member 15 are welded from the outside of the tank 11 by the welding means 21. At this time, in order to optimize the welding state, the energization amount to the electromagnet (excitation means 20) may be changed dynamically or statically.

[0019] Next, as shown in FIG. 1(D), the leakage point 12 is closed without a gap by the welding member 22 with the water stop member 15, and the external leakage of the liquid 16 stored in the tank 11 stops. Then, the excitation means 20 is demagnetized and separated from the tank 11 for recovery.

[0020] (First Embodiment) Next, the first embodiment of the present invention will be described with reference to FIGS. 2 and 3. FIGS. 2(A) and 2(B) are longitudinal sectional views of the leakage water stop device 10A (10) according to the first embodiment. In the leakage water stop device 10A according to the first embodiment as described above, as means for introducing the excitation means 20 into the liquid 16 stored in the tank 11, a crane 25 and a horizontal rail 26 are provided. In FIGS. 2 and 3, parts having the same configuration or function as those in FIG. 1 are denoted by the same reference numerals, and duplicate descriptions are omitted.

[0021] The crane 25 suspends the excitation means 20 and displaces it in the vertical direction. The horizontal rail 26 displaces the crane 25 in the horizontal direction. The horizontal rail 26 is arranged above the tank 11 and can move the crane 25 in one axis or two axes. In the case of a one-axis horizontal rail 26, it is assumed that the fixed positions at both ends can be set at arbitrary positions on the upper edge of the tank 11. Further, the axial rotation angle of the crane 25 may be arbitrarily adjusted so that the direction of the magnetic flux generated by the excitation means 20 can be adjusted. Thereby, the excitation means 20 can be introduced into the liquid 16 from an arbitrary position and accurately approximated to the leakage point 12.

[0022] Figures 3(A), 3(B), 3(C), and 3(D) are functional diagrams illustrating the support means 27 that mechanically supports the water-stopping member 15 on the excitation means 20 in an embodiment. As shown in Figure 3(A), a protruding support means 27 is erected on the upper part of the excitation means 20. On the other hand, as shown in Figure 3(B), the water-stopping member 15 is provided with a locking member 28 that engages with the support means 27 and locks the water-stopping member 15 to the excitation means 20. The excitation means 20, in its non-excited state, supports the water-stopping member 15 and is integrated with it when it approaches the leak point 12 of the tank 11.

[0023] Then, as shown in Figure 3(C), the excitation means 20, which has switched from the de-excited state to the excited state, makes close contact with the inner surface of the tank 11 and holds the water-sealing member 15. Furthermore, as shown in Figure 3(D), the water-sealing member 15 completely seals the leak point 12 with the welded member 22, and then the excitation means 20 is switched from the excited state to the de-excited state.

[0024] As a result, the integrated excitation means 20 can be separated from the water-sealing member 15 and recovered independently. Although the support means 27 is illustrated in Figure 3, the system is not limited to this, and any mechanism that allows the excitation means 20 and the water-sealing member 15 to be detachably integrated when the excitation means 20 is in a de-excited state can be appropriately adopted.

[0025] (Second Embodiment) Next, a second embodiment of the present invention will be described with reference to Figure 4. Figure 4(A) is a vertical cross-sectional view of the leak-stopping device 10B(10) according to the second embodiment, and Figure 4(B) is a horizontal cross-sectional view thereof. As shown above, the leak-stopping device 10B according to the second embodiment is provided with a vertical rail 29 that displaces the excitation means 20 in the vertical direction as a means for introducing the excitation means 20 into the liquid 16 stored in the tank 11. Note that in Figure 4, parts having the same configuration or function as those in Figure 1 are indicated by the same reference numerals, and redundant explanations are omitted.

[0026] The vertical rail 29 displaces the excitation means 20, which is fixed to the holder, in the vertical direction. The horizontal rail 26 is positioned near the leak point 12 on the inside of the side of the tank 11, allowing the crane 25 to move on a single axis. The single-axis vertical rail 29 can have its fixed positions at both ends set to arbitrary positions close to the side of the tank 11. This allows the excitation means 20 to be introduced into the liquid 16 from directly above the leak point 12, bringing it precisely close to the leak point 12.

[0027] Figures 5(A), 5(B), and 5(C) are explanatory diagrams of the function of the sealing member 18 according to the embodiment. As shown in Figure 5(A), the sealing member 18 is provided on the contact surface of the water-stopping member 15 that is in contact with the tank 11, so as to surround the leak location 12. The sealing member 18 is an elastic material such as rubber. The water-stopping member 15 with the sealing member 18 and the excitation means 20 in a non-excited state are brought close to the leak location 12 of the tank 11.

[0028] Then, as shown in Figure 5(B), the excitation means 20, which has switched from a de-excited state to an excited state, adheres tightly to the inner surface of the tank 11 and clamps the water-sealing member 15. At this time, the sealing member 18 elastically deforms and seals the area around the leak point 12 on the inner surface of the tank 11. Furthermore, as shown in Figure 5(C), the water-sealing member 15 seals the leak point 12 without any gaps using the welding member 22, and then the excitation means 20 is switched from an excited state to a de-excited state, separating the excitation means 20 from the water-sealing member 15 and recovering it separately. As a result, the hydrostatic pressure of the stored liquid is applied to the sealing member 18 but not to the welding member 22. This improves the integrity of the repaired leak point 12 against external leakage of the stored liquid.

[0029] (Third embodiment) Next, a third embodiment of the present invention will be described with reference to Figure 6. Figures 6(A), 6(B), 6(C), and 6(D) are explanatory diagrams of the steps of the leak-stopping method according to the third embodiment. In Figure 6, parts that have the same configuration or function as those in Figure 1 are indicated by the same reference numerals, and redundant explanations are omitted.

[0030] As shown in Figure 6(A), the water-stopping member 15 and the excitation means 20 are added to the liquid 16 stored in the tank 11. Both methods of adding the two components are possible: adding them separately or adding them pre-assembled. In the third embodiment, since the water-stopping member 15 is to be recovered at the end, the water-stopping member 15 and the excitation means 20 may be integrated to prevent separation.

[0031] Then, as shown in Figure 6(B), the leak point 12 of the tank 11 is sealed from the inside with a water-stopping member 15. Note that the water-stopping member 15 does not need to completely seal the leak point 12; it is sufficient if it seals the water to the extent that welding of the repair member 23 can be performed afterward.

[0032] Next, as shown in Figure 6(C), the excitation means 20 is placed on either side of the water-stopping member 15 and energized to magnetize the tank 11. As a result, the water-stopping member 15 is tightly attached to the leak point 12. In this state, the repair member 23 is placed on the outside of the tank 11 to cover the leak point 12. Then, the outer circumference of the repair member 23 is welded by the welding means 21.

[0033] Next, as shown in Figure 6(D), the leak point 12 is sealed completely by the repair member 23 with the welded member 22, stopping the external leakage of the liquid 16 stored in the tank 11. Then, the excitation means 20 is demagnetized and separated from the tank 11 together with the water-stopping member 15 for recovery.

[0034] Although not shown in the illustration, the welding means 21 may first weld a water-stopping member 15 that is in close contact with the leak location 12 from the inside of the tank 11, and then weld a repair member 23 that is placed at the leak location 12 from the outside of the tank 11. Furthermore, although not shown in the illustration, a sealing member 18 (see Figure 5) may also be provided on the contact surface of the repair member 23 so as to surround the leak location 12.

[0035] According to the leak-stopping device of at least one embodiment described above, by arranging the excitation means 20 on either side of the water-stopping member 15 at a position that blocks the water-stopping member 15 from the inside relative to the leak location 12, it becomes possible to repair the tank 11 while retaining the liquid.

[0036] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These embodiments can be carried out in a variety of other forms, and various omissions, substitutions, modifications, and combinations are possible without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims and their equivalents. [Explanation of Symbols]

[0037] 10 (10A, 10B)... Leakage stopper, 11... Tank, 12... Leak location, 15... Stopper member, 16... Liquid, 18... Sealing member, 20... Excitation means, 21... Welding means, 22... Welding member, 23... Repair member, 25... Crane, 26... Horizontal rail, 27... Support means, 28... Locking member, 29... Vertical rail.

Claims

1. The process involves sandwiching a water-stopping member with an excitation means at a position that seals the leak from the inside of the tank, A step of exciting the excitation means and magnetizing the tank, A step of welding the periphery of the leak location and the water-stopping member from the outside of the tank, A method for stopping water leakage, comprising the step of demagnetizing the excitation means, separating it from the tank, and recovering it.

2. The leak-stopping method according to claim 1, wherein a sealing member is provided on the contact surface of the water-stopping member that is in contact with the tank, so as to surround the leak location.

3. The process involves sandwiching a water-stopping member with an excitation means at a position that seals the leak from the inside of the tank, A step of exciting the excitation means and magnetizing the tank, A step of welding a repair member to the outside of the tank at a position that seals the leak location, A method for stopping water leakage, comprising the step of demagnetizing the excitation means, separating it from the tank, and recovering it.

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