Method and apparatus for dismantling a calandria container underwater

Abstract

The present invention provides a method and apparatus for the underwater dismantling of a calandria vessel, which allows for the safe dismantling of the calandria vessel and fuel pipes in an underwater environment while reducing worker exposure, using various types of devices that can be detachably attached to an operating device provided on a concrete bolt. [Solution] A method for dismantling a calandria container underwater is provided, comprising: a filling step of filling the inside of a concrete bolt on which a calandria container is provided with water; an installation step of installing an operating device on the concrete bolt; an opening step of dismantling the RM-deck and opening the concrete bolt; an upper part dismantling step of using the operating device to cut and dismantle the upper part of the calandria container and the fuel pipes located inside the upper part of the calandria container; and a lower part dismantling step of using the operating device to cut and dismantle the lower part of the calandria container and the fuel pipes located inside the lower part of the calandria container.

Description

[Technical Field]

[0001] The present invention relates to an underwater dismantling method and apparatus for a calandria tank. More specifically, the present invention relates to an underwater dismantling method and apparatus for a calandria tank that enables safe dismantling of the calandria tank and fuel pipes in an underwater environment while reducing exposure of workers by using various types of apparatuses detachably attached to a manipulator installed in a concrete vault. [Background Art]

[0002] Generally, among nuclear facilities used for nuclear power generation, a heavy water reactor facility includes a calandria, a calandria vault that houses the calandria therein, and known structures located inside and outside the calandria. Conventionally, while there have been cases where some of the structures located inside and outside the calandria have been replaced, there has been no case where the entire heavy water reactor facility including the calandria has been dismantled.

[0003] When dismantling a reactor of a heavy water reactor type nuclear facility, radiation exposure occurs due to the dismantling. Therefore, it is required to prevent such exposure, and reduce or prevent the occurrence of contamination due to diffusion of radioactive contaminants. However, at present, there is a problem that countermeasures for stable and effective dismantling of heavy water reactor type nuclear power plants either do not exist or are insufficient. [Summary of the Invention] [Problem to be Solved by the Invention]

[0004] An object of the present invention is to provide an underwater dismantling method and apparatus for a calandria tank that enables safe dismantling of the calandria tank and fuel pipes in an underwater environment while reducing exposure of workers by using various types of apparatuses detachably attached to a manipulator installed in a concrete vault.

[0005] The technical problems that this invention aims to solve are not limited to those described above, and other technical problems not mentioned will be clearly understood by those with ordinary skill in the art to which this invention pertains from the following description. [Means for solving the problem]

[0006] To solve the above problems, one embodiment of the present invention provides a method for dismantling a calandria container underwater, comprising: a filling step of filling the inside of a concrete vault on which a calandria container is provided with water; an installation step of installing an operating device on the concrete vault; an opening step of dismantling the RM-deck (Reactivity-Mechanism deck) and opening the concrete vault; an upper part dismantling step of using the operating device to cut and dismantle the upper part of the calandria container and the fuel pipes located inside the upper part of the calandria container; and a lower part dismantling step of using the operating device to cut and dismantle the lower part of the calandria container and the fuel pipes located inside the lower part of the calandria container.

[0007] Depending on the embodiment, the upper dismantling step may include a first container dismantling step in which at least a portion of the upper part of the calandria container is cut using a first cutting device attached to the operating device, and at least a portion of the cut upper part is grasped and lifted using a first handling device attached to the operating device, and a first fuel pipe dismantling step in which both ends of the fuel pipe exposed after the first container dismantling step are cut using a second cutting device attached to the operating device, and the cut fuel pipe is grasped and lifted using a second handling device.

[0008] Depending on the embodiment, the first container dismantling step and the first fuel pipe dismantling step may be repeated on a portion of the upper part of the calandria container.

[0009] Depending on the embodiment, after the first container dismantling step and before the first fuel pipe dismantling step, the first cutting device and the first handling device may be separated from the operating device and the second cutting device may be attached.

[0010] Depending on the embodiment, the lower dismantling step may include: a second container dismantling step in which a portion of the lower part of the calandria container is cut using a first cutting device attached to the operating device, and the cut portion of the lower part is grasped and lifted using a first handling device attached to the operating device; a second fuel pipe dismantling step in which both ends of the fuel pipe exposed after the second container dismantling step are cut using a second cutting device attached to the operating device, and the cut fuel pipe is grasped and lifted using a second handling device; a third fuel pipe dismantling step in which both ends of the fuel pipe located inside the last remaining portion of the lower part of the calandria container are cut using a second cutting device attached to the operating device, and the cut fuel pipe is grasped and lifted using a second handling device; and a third container dismantling step in which the last remaining portion of the lower part of the calandria container is grasped and lifted using a first handling device attached to the operating device.

[0011] Depending on the embodiment, the second container dismantling step and the second fuel pipe dismantling step may be repeated on a portion of the lower part of the calandria container.

[0012] Depending on the embodiment, the second cutting device may be separated from the operating device after the first fuel pipe dismantling step and before the second container dismantling step, and the first cutting device and the first handling device may be attached.

[0013] Depending on the embodiment, in the first container dismantling step and the second container dismantling step, the calandria container may be cut by a thermal cutting method.

[0014] Depending on the embodiment, in the first fuel pipe dismantling step, the second fuel pipe dismantling step, and the third fuel pipe dismantling step, the fuel pipe may be cut by a mechanical cutting method.

[0015] To solve the above problems, one embodiment of the present invention provides an underwater dismantling device for a calandria container, characterized in that the calandria container includes an operating device provided on concrete bolts located inside the container, a first cutting device and a first handling device are attached to the operating device when dismantling the calandria container, and a second cutting device is attached to the operating device when dismantling the fuel pipes located inside the calandria container.

[0016] Depending on the embodiment, the operating device may include a main body provided on the concrete bolt, a pair of extensions extending from the main body into the interior of the concrete bolt and having adjustable length, and a pair of mounting parts provided on each of the pair of extensions.

[0017] Depending on the embodiment, when dismantling the calandria container, a first cutting device for cutting the calandria container may be attached to one of the pair of mounting parts, and a first handling device for gripping and lifting the cut calandria container may be attached to the other.

[0018] Depending on the embodiment, when the fuel pipe is dismantled, a pair of second cutting devices for cutting the fuel pipe may be attached to each of the pair of mounting portions.

[0019] Depending on the embodiment, the pair of second cutting devices may be arranged parallel to each other and spaced apart so as to correspond to both ends of the fuel pipe.

[0020] Depending on the embodiment, a second handling device for gripping and lifting the severed fuel pipe may be further included. [Effects of the Invention]

[0021] According to the present invention, various types of devices detachably attachable to an operating device provided on a concrete bolt can be used to safely dismantle a calandria container and fuel pipes in an underwater environment while reducing exposure of workers. In particular, it is safe because the operating device is installed before the RM-deck is opened, and after the RM-deck is opened, the operating device is used to dismantle the calandria container and the fuel pipes in an underwater environment.

[0022] Further, a device suitable for the operating device is attached according to the work process, and the device is detachable and easily replaceable, so a plurality of operations can be easily performed using one operating device. Specifically, when dismantling the calandria container, a first cutting device and a first handling device may be attached to the operating device, and when dismantling the fuel pipe, a second cutting device may be attached to the operating device.

[0023] The effects of the present invention are not limited to the above effects, and it should be understood to include all effects that can be inferred from the configuration of the invention described in the detailed description of the present invention or the claims. [BRIEF DESCRIPTION OF THE DRAWINGS]

[0024] [Figure 1] FIG. 1 is a diagram illustrating an underwater dismantling method for a calandria container according to an embodiment of the present invention. [Figure 2] FIG. 2 is a diagram illustrating in detail an upper part dismantling step and a lower part dismantling step of FIG. 1. [Figure 3] FIG. 3 is a diagram showing a state after a water filling step in FIG. 1. [Figure 4] FIG. 4 is a diagram showing a state after an installation step and an opening step in FIG. 1. [Figure 5-1] FIGS. 5a and 5b are diagrams showing a calandria container dismantled by the upper part dismantling step of FIG. 2. [Figure 5-2] FIG. 5c is a diagram showing a calandria container dismantled by the upper part dismantling step of FIG. 2. [Figure 6-1] FIG. 6a is a diagram illustrating in detail a calandria container and a fuel pipe dismantled by the lower part dismantling step of FIG. 2. [Figure 6-2] Figure 6b is a detailed view of the calandria vessel and fuel pipes being dismantled by the lower dismantling step shown in Figure 2. [Figure 6-3] Figures 6c and 6d show in detail the calandria vessel and fuel pipes being dismantled by the lower dismantling step in Figure 2. [Figure 6-4] Figures 6e and 6f show in detail the calandria vessel and fuel pipes that are dismantled by the lower dismantling step in Figure 2. [Figure 7] This figure shows the state of cutting a calandria container using the first cutting device. [Figure 8] This diagram shows the handling of a calandria container using the first handling device. [Figure 9] This diagram shows the installation of a second cutting device and a second handling device for dismantling the fuel pipe channel. [Figure 10] This diagram shows the state of cutting both ends of the fuel pipe using the second cutting device. [Figure 11] This diagram shows the handling of the fuel pipe using the second handling device. [Modes for carrying out the invention]

[0025] Hereinafter, preferred embodiments of the underwater dismantling method and apparatus for a calandria container of the present invention will be described with reference to the attached drawings.

[0026] Furthermore, the terms described below are defined in consideration of the functions of the present invention, and these may vary depending on the intent or practice of the user or operator. The following embodiments do not limit the scope of the rights of the present invention, but are merely illustrative of the components presented in the claims of the present invention.

[0027] To clearly illustrate the present invention, irrelevant parts have been omitted, and the same or similar reference numerals are used throughout the specification for identical or similar components. Wherever a part of the specification is described as "including" a component, this does not mean that other components are excluded, unless otherwise stated.

[0028] Furthermore, throughout the specification, components referred to as "~part" may be two or more components combined into one, or one component may be subdivided into two or more based on more detailed functions. In addition, each of the components described below may perform some or all of the functions performed by other components, in addition to its own main function, and it goes without saying that some of the functions of the main function performed by each component may be exclusively performed by other components.

[0029] A method for dismantling a calandria container underwater according to one embodiment of the present invention includes a water filling step (S1), an installation step (S2), an opening step (S3), an upper dismantling step (S4), and a lower dismantling step (S5).

[0030] In the filling step (S1), the inside of the concrete bolt 100, which is equipped with a calandria container 200, is filled with water. Figure 3 shows the state after the filling step (S1), showing that the calandria container 200 is completely submerged in water. The concrete bolt 100 is closed off by the RM-deck (Reactivity-Mechanism deck) 10 covering the top.

[0031] In the installation step (S2), the actuator 400 is installed on the concrete bolt 100. The actuator 400 is located on the top of the concrete bolt 100 and may extend into the interior of the concrete bolt 100 after the release step (S3). The detailed structure of the actuator 400 will be discussed in detail below.

[0032] In the opening step (S3), the RM-deck 10 is dismantled and the concrete bolts 100 are opened. In this way, the operating device 400 is installed before the concrete bolts 100 are opened, and the concrete bolts 100 are opened after the inside of the concrete bolts 100 are filled with water. As a result, radioactive contaminants inside the concrete bolts 100 do not spread, and the exposure of workers to radiation can be reduced.

[0033] After the RM-deck 10 is dismantled in the opening step (S3), a vertical reactivity structure dismantling step (S6) can be performed to dismantle the vertical reactivity structure, which includes a vertical reactivity controller 20 that is inserted into the protruding lugs 210 of the calandria vessel 200 and extends to the RM-deck 10.

[0034] Figure 4 shows the state after the installation step (S2), the release step (S3), and the vertical reactivity structure dismantling step (S6).

[0035] Subsequently, the calandria container 200 and the fuel pipes 300 located inside it are dismantled. First, an upper dismantling step (S4) is performed in which the upper part of the calandria container 200 and the fuel pipes 300 located inside the upper part of the calandria container 200 are cut and dismantled using an operating device 400. Then, a lower dismantling step (S5) is performed in which the lower part of the calandria container 200 and the fuel pipes 300 located inside the lower part of the calandria container 200 are cut and dismantled using an operating device 400.

[0036] Specifically, the upper dismantling step (S4) includes a first container dismantling step (S4-1) in which at least a portion of the upper part of the calandria container 200 is cut using a first cutting device 500 attached to the operating device 400, and at least a portion of the cut upper part is grasped and lifted using a first handling device 600 attached to the operating device 400, and a first fuel pipe dismantling step (S4-2) in which both ends of the fuel pipe 300 exposed after the first container dismantling step (S4-1) are cut using a second cutting device 700 attached to the operating device 400, and the cut fuel pipe is grasped and lifted using a second handling device 800.

[0037] In this case, if the entire upper part of the calandria container 200 is cut and dismantled, and then the fuel pipe 300 of the entire upper part is cut and dismantled, the first container dismantling step (S4-1) and the first fuel pipe dismantling step (S4-2) will be performed once each. However, in some cases, the first container dismantling step (S4-1) and the first fuel pipe dismantling step (S4-2) may be repeated for each portion of the upper part of the calandria container 200.

[0038] In this embodiment, the upper part of the calandria container 200 is divided into two parts and dismantled in halves. Therefore, as shown in Figure 2, first, area A, which corresponds to 1 / 2 of the upper part of the calandria container 200, is cut and dismantled, then the fuel pipe 300 in the exposed area A is cut and dismantled, and then area B, which corresponds to the remaining 1 / 2 of the upper part of the calandria container 200, is cut and dismantled, and then the fuel pipe 300 in the exposed area B is cut and dismantled. Here, as shown in Figure 5a, area A corresponds to 1 / 2 of the upper part in the height direction from the top of the calandria container 200, and area B corresponds to the remaining 1 / 2 of the upper part in the height direction from the end point of area A, as shown in Figure 5b.

[0039] When dismantling the upper part of the calandria container 200, the fuel pipe 300 is located inside the calandria container 200, and because the calandria container 200 has a cylindrical shape, the fuel pipe 300 cannot be dismantled due to interference unless the calandria container 200 is dismantled first.

[0040] In the first container dismantling step (S4-1), the first cutting device 500 and the first handling device 600 are attached to the operating device 400, and in the first fuel line dismantling step (S4-2), the second cutting device 700 is attached to the operating device 400. Therefore, after the first container dismantling step (S4-1) and before the first fuel line dismantling step (S4-2), the first cutting device 500 and the first handling device 600 may be separated from the operating device 400, and the second cutting device 700 may be attached. Conversely, when transitioning from the first fuel line dismantling step (S4-2) to the first container dismantling step (S4-1), the second cutting device 700 will be separated from the operating device 400, and the first cutting device 500 and the first handling device 600 will be attached.

[0041] The lower section dismantling step (S5) includes a second container dismantling step (S5-1) in which a portion of the lower section of the calandria container 200 is cut using a first cutting device 500 attached to the operating device 400, and the cut portion of the lower section is grasped and lifted using a first handling device 600 attached to the operating device 400, and a second fuel pipe dismantling step (S5-2) in which both ends of the fuel pipe 300 exposed after the second container dismantling step (S5-1) are cut using a second cutting device 700 attached to the operating device 400, and the cut fuel pipe is grasped and lifted using a second handling device 800. Furthermore, the lower section dismantling step (S5) further includes a third fuel pipe dismantling step (S5-3) in which the ends of the fuel pipe 300 located inside a portion of the lower section of the last remaining calandria container 200 are cut using a second cutting device 700 attached to the operating device 400, and the cut fuel pipes are grasped and lifted up using a second handling device 800, and a third container dismantling step (S5-4) in which a portion of the lower section of the last remaining calandria container 200 is grasped and lifted up using a first handling device 600 attached to the operating device 400.

[0042] When dismantling the lower part of the calandria container 200, it is desirable to dismantle the calandria container 200 first, and then dismantle the exposed fuel pipe 300, in order to minimize interference with the calandria container 200. However, in the end, since it is not possible to dismantle the remaining lower part unless the fuel pipe 300 is removed first, the fuel pipe 300 is dismantled first, and then the calandria container 200 is dismantled.

[0043] For this purpose, the lower part of the calandria container 200 is dismantled in increments of at least 1 / 2. In this case, the second container dismantling step (S5-1), the second fuel pipe dismantling step (S5-2), the third fuel pipe dismantling step (S5-3), and the third container dismantling step (S5-4) will each be performed once. However, in some cases, if the lower part of the calandria container 200 is dismantled in increments of 1 / 3, 1 / 4, or smaller portions, the second container dismantling step (S5-1) and the second fuel pipe dismantling step (S5-2) may be repeated for each portion of the lower part of the calandria container 200. Even in this case, the third fuel pipe dismantling step (S5-3) and the third container dismantling step (S5-4) will be performed only once at the end.

[0044] In this embodiment, the lower part of the calandria container 200 is divided into three parts and dismantled in 1 / 3 increments. Therefore, as shown in Figure 2, first, the C region corresponding to 1 / 3 of the lower part of the calandria container 200 is cut and dismantled, then the fuel pipe 300 in the exposed C region is cut and dismantled, then the D region corresponding to 1 / 3 of the lower part of the calandria container 200 is cut and dismantled, then the fuel pipe 300 in the exposed D region is cut and dismantled. After that, the fuel pipe 300 located in the E region, which corresponds to the last remaining 1 / 3 of the lower part of the calandria container 200, is cut and dismantled, and then the last remaining E region of the calandria container 200 is dismantled. Here, as shown in Figure 6a, the C region corresponds to 1 / 3 of the lower part in the height direction from the halfway point of the calandria container 200, the D region corresponds to 1 / 3 of the lower part in the height direction from the end point of the C region, as shown in Figure 6c, and the E region corresponds to the remaining 1 / 3 of the lower part in the height direction from the end point of the D region, as shown in Figure 6e.

[0045] Figures 5c and 6a show the state where the upper part of the calandria container 200 has been dismantled and the lower part remains. Figure 6b shows the state where region C of the lower part of the calandria container 200 has been dismantled, Figure 6c shows the state where the fuel pipe 300 in region C has been dismantled, Figure 6d shows the state where region D of the lower part of the calandria container 200 has been dismantled, Figure 6e shows the state where the fuel pipe 300 in region D has been dismantled, and Figure 6f shows the state where the fuel pipe 300 in region E has been dismantled and only region E of the lower part of the calandria container 200 remains.

[0046] In the first to third fuel pipe dismantling steps (S4-2, S5-2, S5-3), the fuel pipes 300 may be cut and dismantled one by one. Also, in the first and second container dismantling steps (S4-1, S5-1), it was explained that one region of the calandria container 200 to be dismantled is cut and dismantled at once, but in some cases it may be cut into multiple pieces and dismantled. Similarly, in the third container dismantling step (S5-4), it was explained that the calandria container 200 is dismantled without cutting, but in some cases it may be cut into multiple pieces and dismantled.

[0047] In the first fuel line dismantling step (S4-2), the second cutting device 700 is attached to the operating device 400, and in the second container dismantling step (S5-1), the first cutting device 500 and the first handling device 600 are attached to the operating device 400. Therefore, after the first fuel line dismantling step (S4-2) and before the second container dismantling step (S5-1), the second cutting device 700 may be separated from the operating device 400, and the first cutting device 500 and the first handling device 600 may be attached.

[0048] Similarly, when transitioning from the second container dismantling step (S5-1) to the second fuel line dismantling step (S5-2), the first cutting device 500 and the first handling device 600 will be separated from the operating device 400, and the second cutting device 700 will be attached. Conversely, when transitioning from the second fuel line dismantling step (S5-2) to the second container dismantling step (S5-1), the second cutting device 700 will be separated from the operating device 400, and the first cutting device 500 and the first handling device 600 will be attached.

[0049] In the first container dismantling step (S4-1) and the second container dismantling step (S5-1), the calandria container 200 may be cut by a thermal cutting method, such as a laser cutting method. Since the calandria container 200 is made of stainless steel, a thermal cutting method is applicable, and since the work needs to be done from the RM-deck 10 to a depth of 15 m, a non-contact cutting method can be applied.

[0050] Furthermore, in the first fuel tube dismantling step (S4-2), the second fuel tube dismantling step (S5-2), and the third fuel tube dismantling step (S5-3), the fuel tube 300 may be cut by a mechanical cutting method. Since the fuel tube 300 is made of Zircaloy alloy, its brittleness is increased by neutrons, and a mechanical cutting method that can be operated at a low speed can be applied. Although the fuel tube 300 can also be cut with a laser, it is preferable to use a mechanical cutting method considering spatial problems and the fact that the fuel tube 300 is a double tube including a calandria tube and a pressure tube located inside the calandria tube, making cutting underwater difficult.

[0051] After the lower section demolition step (S5), a drainage step (S7) is performed to drain the inside of the concrete bolt 100. Subsequently, steps to demolish other structures within the concrete bolt 100 can be performed, such as a feeder / end fitting demolition step (S8) to demolish the feeder and end fitting, and a horizontal reactivity structure demolition step (S9) to demolish the horizontal reactivity structure.

[0052] Next, with reference to Figures 4 and 7 to 11, we will examine in detail a method for dismantling a calandria container 200 and fuel pipes 300 using an underwater dismantling apparatus for a calandria container according to one embodiment of the present invention.

[0053] The underwater dismantling device for the calandria vessel includes an operating device 400 attached to a concrete bolt 100. When dismantling the calandria vessel 200, a first cutting device 500 and a first handling device 600 are attached to the operating device 400, and when dismantling the fuel pipe 300, a second cutting device 700 is attached to the operating device 400.

[0054] Specifically, the operating device 400 may include a main body 410 provided on the concrete bolt 100, a pair of length-adjustable extensions 420 extending from the main body 410 into the interior of the concrete bolt 100, and a pair of mounting parts 430 provided on each of the pair of extensions 420.

[0055] As shown in Figures 7 and 8, when dismantling the calandria container 200, a first cutting device 500 for cutting the calandria container 200 is attached to one of the pair of mounting parts 430, and a first handling device 600 for gripping and lifting the cut calandria container 200 is attached to the other. The first cutting device 500 and the first handling device 600 are detachably attached to the pair of mounting parts 430.

[0056] As a result, in the first container dismantling step (S4-1) and the second container dismantling step (S5-1), the calandria container 200 can be cut using the first cutting device 500, as shown in Figure 7. In this embodiment, the first cutting device 500 is a laser cutting device. The calandria container 200 is cut using the first cutting device 500 according to the designed cutting plan.

[0057] Furthermore, in the first container dismantling step (S4-1) and the second container dismantling step (S5-1), as shown in Figure 8, the cut calandria container 200 can be gripped and lifted using the first handling device 600. In this embodiment, the first handling device 600 is a gripper in which two straight fingers 610, which can be inserted into a protruding lug 210 into which the vertical reactivity controller 20 is inserted, move in parallel. As a result, one of the two straight fingers 610 is inserted into the protruding lug 210, and the other moves in parallel to grip the protruding lug 210 from the outside, thereby allowing the calandria container 200 to be stably gripped and lifted.

[0058] As shown in Figures 9 to 11, when dismantling the fuel pipe 300, a pair of second cutting devices 700 for cutting the fuel pipe 300 are attached to each of the pair of mounting sections 430. The underwater dismantling apparatus for the calandria vessel may further include a second handling device 800 for gripping and lifting the cut fuel pipe 300. In this embodiment, the second handling device 800 is not attached to the pair of mounting sections 430, but is provided on a separate structure in an adjustable length manner. However, it is not limited to this, and in some cases, the second handling device 800 may also be provided on the operating device 400. The second cutting devices 700 are detachably attached to the pair of mounting sections 430.

[0059] As a result, in the first fuel pipe dismantling step (S4-2), the second fuel pipe dismantling step (S5-2), and the third fuel pipe dismantling step (S5-3), both ends of the fuel pipe 300 can be cut using the second cutting device 700, as shown in Figure 10. In this embodiment, the second cutting device 700 is a diamond wheel saw. At this time, the pair of second cutting devices 700 are arranged parallel to each other and spaced apart so as to correspond to both ends of the fuel pipe 300, so that both ends of the fuel pipe 300 can be cut.

[0060] Furthermore, in the first fuel pipe dismantling step (S4-2), the second fuel pipe dismantling step (S5-2), and the third fuel pipe dismantling step (S5-3), as shown in Figure 11, the cut fuel pipe 300 can be gripped and lifted using the second handling device 800. In this embodiment, the second handling device 800 may be a gripper equipped with two curved fingers 810 at both ends, which are angle-adjustable to surround the fuel pipe 300. This allows the two curved fingers 810 to completely surround the cut fuel pipe 300 at two positions, enabling a stable grip and lifting of the fuel pipe 300.

[0061] The present invention is not limited to the specific embodiments and descriptions described above, and various modifications can be carried out by a person with ordinary skill in the art to which the present invention belongs without departing from the gist of the invention claimed in the claims, and such modifications are within the scope of protection of the present invention. [Explanation of Symbols]

[0062] S1: Water filling step S2: Installation step S3: Opening step S4: Upper section dismantling step S4-1: First container dismantling step S4-2: First fuel line dismantling step S5: Lower part dismantling step S5-1: Second container dismantling step S5-2: Second fuel pipe dismantling step S5-3: Third fuel pipe dismantling step S5-4: Third container dismantling step S6: Vertical reactivity structure dismantling step S7: Drainage step S8: Feeder / end fitting dismantling step S9: Horizontal Reactivity Structure Demolition Step 10: RM-deck 20: Vertical reactivity controller 100: Concrete bolts 200: Calandria containers 210: Protruding lug 300: Fuel pipe 400: Operating device 410: Main unit 420: Extension part 430: Mounting part 500: First cutting device 600: First handling device 610: Straight finger 700: Second cutting device 800: Second handling device 810: Curved finger

Claims

1. A filling step involves filling the inside of a concrete vault equipped with a calandria container with water, Installation step of installing the operating device on the concrete bolt, An opening step to dismantle the RM-deck (Reactivity-Mechanism deck) and release the concrete bolts, Using the aforementioned operating device, the upper part dismantling step involves cutting and dismantling the upper part of the calandria container and the fuel pipes located inside the upper part of the calandria container, A method for dismantling a calandria container underwater, comprising: a lower dismantling step of using the operating device to cut and dismantle the lower part of the calandria container and the fuel pipes located inside the lower part of the calandria container.

2. The aforementioned upper part dismantling step is, A first container dismantling step involves using a first cutting device attached to the operating device to cut at least a portion of the upper part of the calandria container, and using a first handling device attached to the operating device to grasp and lift up at least a portion of the cut upper part, A method for dismantling a calandria container underwater according to claim 1, comprising: a first fuel pipe dismantling step of using a second cutting device attached to the operating device to cut both ends of the fuel pipe exposed after the first container dismantling step, and using a second handling device to grasp and lift the cut fuel pipe.

3. The method for dismantling a calandria container underwater according to claim 2, wherein the first container dismantling step and the first fuel pipe dismantling step are repeated in portions of the upper part of the calandria container.

4. The method for dismantling a calandria vessel underwater according to claim 2, wherein after the first vessel dismantling step and before the first fuel pipe dismantling step, the first cutting device and the first handling device are separated from the operating device and the second cutting device is attached.

5. The aforementioned lower part dismantling step is, A second container dismantling step involves using a first cutting device attached to the operating device to cut a portion of the lower part of the calandria container, and using a first handling device attached to the operating device to grasp and lift the cut portion of the lower part, A second fuel pipe dismantling step is to use a second cutting device attached to the operating device to cut both ends of the fuel pipe exposed after the second container dismantling step, and to use a second handling device to grasp and lift the cut fuel pipe, A third fuel pipe dismantling step involves using a second cutting device attached to the aforementioned operating device to cut both ends of the fuel pipe located inside the last remaining lower part of the calandria container, and using a second handling device to grasp and lift the cut fuel pipe, A method for dismantling a calandria container underwater according to any one of claims 2 to 4, comprising: a third container dismantling step of using a first handling device attached to the operating device to grasp and lift up a portion of the lower side of the last remaining calandria container.

6. The method for dismantling a calandria container underwater according to claim 5, wherein the second container dismantling step and the second fuel pipe dismantling step are repeated in portions of the lower part of the calandria container.

7. The method for dismantling a calandria vessel underwater according to claim 5, wherein after the first fuel pipe dismantling step and before the second vessel dismantling step, the second cutting device is separated from the operating device and the first cutting device and the first handling device are attached.

8. The method for dismantling a calandria container underwater according to claim 5, wherein in the first container dismantling step and the second container dismantling step, the calandria container is cut by a thermal cutting method.

9. The method for dismantling a calandria vessel underwater according to claim 8, wherein in the first fuel pipe dismantling step, the second fuel pipe dismantling step, and the third fuel pipe dismantling step, the fuel pipes are cut by a mechanical cutting method.

10. The calandria container includes an operating mechanism attached to a concrete bolt located inside, An underwater dismantling apparatus for a calandria container, wherein a first cutting device and a first handling device are attached to the operating device when dismantling the calandria container, and a second cutting device is attached to the operating device when dismantling the fuel pipes located inside the calandria container.

11. The underwater dismantling apparatus for a calandria container according to claim 10, wherein the operating device includes a main body provided on the concrete bolt, a pair of extensions extending from the main body into the interior of the concrete bolt and having adjustable length, and a pair of mounting parts provided on each of the pair of extensions.

12. The underwater dismantling apparatus for a calandria container according to claim 11, wherein, when dismantling the calandria container, a first cutting device for cutting the calandria container is attached to one of the pair of mounting parts, and a first handling device for gripping and lifting the cut calandria container is attached to the other.

13. The underwater dismantling apparatus for a calandria container according to claim 11 or 12, wherein, when dismantling the fuel pipe, a pair of second cutting devices for cutting the fuel pipe are attached to each of the pair of mounting portions.

14. The underwater dismantling apparatus for a calandria container according to claim 13, wherein the pair of second cutting devices are arranged parallel to each other and spaced apart so as to correspond to both ends of the fuel pipe.

15. The underwater dismantling apparatus for a calandria vessel according to claim 13, further comprising a second handling device for gripping and lifting the severed fuel pipe.

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