Apparatus and method for separating shielding ball

Abstract

An apparatus and a method for separating a shielding ball are disclosed. An apparatus for separating a shielding ball comprises: an end shield which is installed in a spinning structure of a heavy water reactor facility and includes a fueling tubesheet and a calandria tubesheet facing each other and multiple shielding balls for filling a space between the calandria tubesheet and the fueling tubesheet; as a device for removing the shielding balls from a lattice tube connected to the calandria tube by being connected to the calandria tubesheet through the fueling tubesheet, a magnetic force applying unit inserted into the lattice tube in a direction of the fueling tubesheet to apply a magnetic force for fixing positions of the multiple shielding balls positioned within a first distance from the calandria tubesheet; a mover for moving the magnetic force applying unit in a direction of the lattice tube; and a storage rack for separately storing, inside the end shield, the shielding balls positioned within the first distance from the calandria tubesheet and shielding balls positioned at a distance greater than the first distance.

Description

Shielding ball separation device and method

[0001] The present invention relates to a shield ball separation device and method for separating and removing shield balls inside a terminal shield according to low-level or medium-level states.

[0002] Typically, the shielding ball is a ball inserted inside the end shield installed on both sides of the calandria.

[0003] The shielding balls are made of carbon steel, measure 9.5 to 12.5 mm, and weigh approximately 88 tons per terminal shield. The shielding balls within the terminal shield, along with the water, serve to shield radiation generated by the nuclear fuel.

[0004] Additionally, the shielding ball part close to the nuclear fuel channel in contact with the calandria side tube sheet due to long-term operation was evaluated as intermediate-level radioactive waste, and the outer shielding ball part close to the fuel exchanger side tube sheet was evaluated as low-level radioactive waste.

[0005] These shielding balls must be removed before dismantling the end shield.

[0006] There have been no practical applications of this method for removing the shielding balls. While domestic and international proposals involve removing the upper grid tube and extracting the shielding balls for collection, this method does not meet domestic radioactive waste classification standards, which classify them into intermediate-level and low-level radioactive waste.

[0007] One embodiment of the present invention provides a shielding ball separation device and method that collects shielding balls in a terminal shield body by position, such as medium-level shielding balls in a calandria-side tube sheet region and low-level shielding balls in a fuel exchanger-side tube sheet region, using an electromagnet, and separates radioactive waste by level according to the position.

[0008] One embodiment of the present invention is a device for removing shield balls from a lattice tube that is installed in a radioactive structure of a heavy water reactor facility and includes a fueling tube sheet and a calandria tube sheet facing each other, an end shield that fills a space between the fueling tube sheet and the calandria tube sheet, and a device for removing the shield balls from a lattice tube that penetrates the fueling tube sheet and is connected to the calandria tube sheet, the device comprising: a magnetic force applying unit that applies a magnetic force to fix the positions of a plurality of shield balls positioned within a first distance from the calandria tube sheet by being inserted into the lattice tube in the direction of the fueling tube sheet; a moving unit that moves the magnetic force applying unit in the direction of the lattice tube; and a storage rack that separately stores the shield balls positioned within the first distance from the calandria tube sheet and the shield balls positioned at a distance greater than the first distance within the end shield.

[0009] The magnetic force applying unit may include a fixed unit that is inserted and fixed into the moving unit, and an electromagnet that is installed on one side of the fixed unit and inserted into the interior of the grid tube to apply a magnetic force to fix the positions of a plurality of shielding balls within a first distance from the calandria tube sheet.

[0010] The fixed part may include a fixed pipe inserted and fixed into the moving part, and an angle cylinder rotatably connecting the fixed pipe and the electromagnet.

[0011] The mobile device may include a mobile body that is installed to be movable at a work site, and an insert fixing part that is installed on the mobile body and fixes a fixed pipe.

[0012] The above shield ball separation device may further include a withdrawal device that withdraws a plurality of shield balls located at a first distance or more from the calandria tube sheet and moves and stores them in a storage rack.

[0013] The first distance may be 200 mm from the calandria tubesheet.

[0014] One embodiment of the present invention may include the steps of: (a) inserting a magnetic force applying unit into the interior of a grid tube in the direction of the fueling tube sheet; (b) applying a magnetic force to an electromagnet of the magnetic force applying unit of step (a) to fix the positions of a plurality of shielding balls positioned within a first distance from a calandria tube sheet; (c) installing a withdrawer in the inner direction of the terminal shield to separate and remove the plurality of shielding balls positioned at a distance greater than the first distance from the calandria tube sheet and the plurality of shielding balls positioned within the first distance; and (d) storing the shielding balls separated in step (c) in the storage rack.

[0015] The first distance may be 200 mm from the calandria tubesheet.

[0016] According to one embodiment of the present invention, a plurality of shielding balls installed within a terminal shielding body can be separated into low-level and intermediate-level states and stored separately in storage racks. Therefore, stable processing of radioactive waste materials, such as intermediate-level shielding balls, is possible, thereby minimizing worker exposure and ensuring safety during the radioactive waste processing process.

[0017] According to one embodiment of the present invention, the shield ball processing operation can be fully automated, thereby minimizing human accidents and minimizing the work schedule, and effectively reducing the cost of dismantling work.

[0018] According to one embodiment of the present invention, it is possible to extract shielding balls from the terminal shield by location and separate them into intermediate-level and low-level radioactive waste according to the results of the computer simulation radiation evaluation, thereby enabling efficient radioactive waste management.

[0019] Figure 1 is a schematic perspective view of a conventional heavy water reactor facility.

[0020] Figure 2 is a schematic side view of the heavy water reactor facility of Figure 1.

[0021] Figure 3 is an enlarged view of part A of Figure 2.

[0022] FIG. 4 is a schematic drawing showing a state in which an electromagnet is installed inside a grid tube by a shield ball separation device according to one embodiment of the present invention.

[0023] FIG. 5 is a side view schematically illustrating a state in which a magnetic force applying unit is installed by a moving unit of a shield ball separation device according to one embodiment of the present invention.

[0024] Fig. 6 is a schematic perspective view of the main body of the moving device of Fig. 5 with the shielding ball separation device installed.

[0025] Fig. 7 is a side view schematically illustrating a state in which the moving device of Fig. 6 moves and the electromagnet of the magnetic force application unit is installed inside the grid tube.

[0026] Figure 8 is a perspective view schematically illustrating a magnetic force applying unit according to one embodiment of the present invention.

[0027] FIG. 9 is a schematic drawing of a storage rack according to one embodiment of the present invention.

[0028] Figure 10 is a flowchart schematically illustrating a shield ball separation method according to one embodiment of the present invention.

[0029] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings so that those skilled in the art can easily implement the present invention. However, the present invention may be implemented in various different forms and is not limited to the embodiments described herein. In the drawings, parts irrelevant to the description have been omitted to clearly explain the present invention, and the same reference numerals have been used throughout the specification to refer to identical or similar components.

[0030] The shielding ball separation device (100) using an electromagnet described below is installed in a radioactive structure of a heavy water reactor facility and refers to a device for removing shielding balls from an end shield including a fueling tubesheet (13a) and a calandria tubesheet (13b) facing each other, and a plurality of shielding balls filling a space between the calandria tubesheet (13b) and the fueling tubesheet (13a).

[0031] That is, the shielding ball separation device (100) using an electromagnet described below is a device for separating and storing shielding balls in a contaminated state expected to be intermediate-level radioactive waste and shielding balls in a low-level state in a storage rack. This will be described in detail below with reference to the drawings.

[0032] FIG. 1 is a schematic perspective view of a conventional heavy water reactor facility, FIG. 2 is a schematic side view of the heavy water reactor facility of FIG. 1, and FIG. 3 is an enlarged view of part A of FIG. 2.

[0033] As illustrated in FIGS. 1 to 3, a heavy water reactor facility may include a calandria (10), a calandria vault (20) that houses the calandria (10) within its interior (21), a cover assembly (30) including a reaction device deck (31) located on the upper portion (22) of the calandria vault (20) and covering the calandria (10), and a reactor tube (40) installed in the calandria (10).

[0034] Calandria (10) may include a main shell (11) located at the center, a sub-shell (12) connected to both ends of the main shell (11), and an end shield (13) connected to the sub-shell (12).

[0035] Internal structures such as a guide tube (51) and a poison injection tube (52) may be installed inside the calandria (10). The guide tube (51) is a pipe for guiding a reactivity control and monitoring device, and the poison injection tube (52) is a pipe for injecting poison for reactor shutdown.

[0036] The terminal shield (13) may include a fueling tubesheet (13a) and a calandria tubesheet (13b) facing each other, a plurality of shielding balls (13c) filling a space between the calandria tubesheet (13b) and the fueling tubesheet (13a), and shielding water (13d). The shielding balls (13c) may be balls made of carbon steel, and the shielding water (13d) may be hard water.

[0037] A calandria vault (20) can support the end shield (13) of a calandria (10) and store the calandria (10) inside (21).

[0038] A shielding slab (50) can be installed at the boundary between the calandria bolt (20) and the terminal shield (13).

[0039] A shielding slab (50) is installed at the boundary between the calandria bolt (20) and the terminal shield (13). This shielding slab (50) is installed to more completely shield the radiation emitted from the calandria (10). The shielding slab (50) may include a plurality of sub-slabs and a fastening member that fastens the plurality of sub-slabs to the calandria bolt (20).

[0040] The cover assembly (30) may include a reactivity mechanism deck (31) that is supported on the upper part of the calandria bolt (20) and covers the calandria (10), an upper guide tube (32) that vertically connects the reactivity mechanism deck (31) and the calandria (10), a side guide tube (33) that is horizontally connected to the calandria (10), pressure relief pipes (34) that are connected to the upper part of the calandria (10) and release the pressure inside the calandria (10) to the outside, and a moderator pipe (35) that is connected to the side and the lower part of the calandria (10) and through which a moderator is introduced and discharged. Control devices such as a control rod and an absorption rod may be inserted into the upper guide tube (32) and the side guide tubes (33).

[0041] The reactor tube (40) may include a coolant feeder tube (41) that supplies coolant to the calandria (10), a pressure tube (42) that horizontally penetrates the calandria (10), a calandria tube (43) that surrounds the pressure tube (42) and is connected to a terminal shield (13), and an end fitting part (44) that is connected to one surface of the terminal shield (13). The coolant feeder tube (41) may be connected to both ends of the pressure tube (42) to supply coolant to the pressure tube (42).

[0042] The calandria tube (43) can be connected to the calandria tube sheet (13b) of the terminal shield (13).

[0043] The upper guide tube (32) is connected to the upper end of the guide tube (51) vertically arranged inside the calandria (10), and the side guide tube (33) can be connected to one end of the poison injection tube (52) horizontally arranged inside the calandria (10).

[0044] The guide pipe (51) is a pipe for guiding the reaction control and monitoring device, and the poison injection pipe (52) is a pipe for injecting poison for stopping the reactor.

[0045] An insulating material (90) may be installed on both sides of the calandria (10). The insulating material (90) may cover the surface of the end fitting part (44) exposed to the outside of the calandria (10) for nuclear fuel replacement. The insulating material (90) may be made of aluminum or the like, but is not necessarily limited thereto.

[0046] In these heavy water reactor facilities, a shield ball separation device (100) of the present embodiment is installed for separation and removal of the shield ball (13c). This will be described in detail below with reference to the drawings.

[0047] FIG. 4 is a schematic drawing showing a state in which an electromagnet is installed inside a grid tube by a shielding ball separation device according to an embodiment of the present invention, and FIG. 5 is a side view schematically showing a state in which a magnetic force application unit is installed by a moving unit of a shielding ball separation device according to an embodiment of the present invention. FIG. 6 is a perspective view schematically showing a state in which a shielding ball separation device is installed in the moving unit of FIG. 5, and FIG. 7 is a side view schematically showing a state in which the moving unit of FIG. 6 moves and an electromagnet of a magnetic force application unit is installed inside a grid tube.

[0048] As illustrated in FIGS. 4 to 7, a shield ball separation device (100) using an electromagnet according to one embodiment of the present invention includes a magnetic force applying unit (110) that applies a magnetic force to fix the positions of a plurality of shield balls (13c) positioned within a first distance from a calandria tube sheet (13b) by being inserted into the interior of a grid tube (13e) in the direction of a fueling tube sheet (13a), a moving unit (130) that moves the magnetic force applying unit (110) in the direction of the grid tube (13e), and a storage rack (150) that separately stores the shield balls (13c) positioned within the first distance from the calandria tube sheet (13b) and the shield balls positioned at a distance greater than the first distance within the interior of the terminal shield (13).

[0049] The magnetic force application unit (110) can be inserted into the interior of the grid tube (13e) while installed in the moving unit (130) described later.

[0050] That is, the magnetic force applying unit (110) is inserted into the interior of the grid tube (13e) in the direction of the fueling tube sheet (13a), and can apply a magnetic force to fix the positions of a plurality of shielding balls (13c) located within a first distance from the calandria tube sheet (13b).

[0051] In this way, the magnetic force applying unit (110) is inserted into the inside of the fueling tube sheet (13a) to fix the current positions of the plurality of shielding balls (13c) located within the first distance from the calandria tube sheet (13b), in order to first remove the plurality of shielding balls (13c) located at a distance greater than the first distance from the calandria tube sheet (13b) from the terminal shield (13).

[0052] That is, the shielding ball (13c) located within the first distance from the calandria tube sheet (13b) corresponds to intermediate-level radioactive waste, and the shielding ball (13c) located beyond the first distance from the calandria tube sheet (13b) corresponds to low-level radioactive waste. Therefore, it is possible to sequentially separate and remove the shielding ball (13c) corresponding to intermediate-level radioactive waste and the shielding ball (13c) corresponding to low-level radioactive waste.

[0053] Figure 8 is a perspective view schematically illustrating a magnetic force applying unit according to one embodiment of the present invention.

[0054] As illustrated in FIG. 8, the magnetic force applying unit (110) may include a fixed unit (11) that is inserted and fixed into a moving unit (130), and an electromagnet (113) that is installed on one side of the fixed unit (11) and inserted into the interior of a grid tube (13e) to apply a magnetic force to fix the positions of a plurality of shielding balls (13c) within a first distance from a calandria tube sheet (13b).

[0055] The fixed part (11) is formed in a cylindrical shape and is inserted and fixed into the inside of the moving part (130), and can be detachably fixed to the moving part (130).

[0056] This fixed part (11) may include a fixed pipe (111a) that is inserted and fixed into a moving part (130), and an angle cylinder (111b) that rotatably connects between the fixed pipe (111a) and an electromagnet (113).

[0057] The fixed pipe (111a) is a cylindrical pipe shape that is detachably fixed while inserted into the inside of the moving device (130), and an angle cylinder (111b) can be installed on one side in a state where the angle can be adjusted.

[0058] The angle cylinder (111b) is connected to a fixed pipe (111a) on one side and is rotatably connected to an electromagnet (113) on the other side, so that a magnetic force can be easily applied to fix the position of the shield ball (13c), and the shield ball (13c) can be easily withdrawn by the magnetic force when withdrawn.

[0059] The electromagnet (113) is installed at the end of the angle cylinder (111b), and can be installed so that the electromagnet can be selectively applied by the operator's control while inserted into the interior of the grid tube (13e). The electromagnet (113) can be separated from the angle cylinder (111b) while inserted into the interior of the grid tube (13e).

[0060] This electromagnet (113) is inserted into the interior of the grid tube (13e) from the side of the fueling tube sheet (13a), and can apply magnetic force to a plurality of shielding balls (13c) located within a first distance from the calandria tube sheet (13b) inside the terminal shield (13).

[0061] Accordingly, multiple shielding balls (13c) corresponding to intermediate-level waste can be fixed at a position within a first distance from the calandria tube sheet (13b), and the shielding balls (13c) corresponding to low-level waste can be made to be preferentially removable from the inside of the terminal shield (13).

[0062] These electromagnets (113) are individually taken out while being stored in multiple units in the initial storage unit (120) and connected by an angle cylinder (111b), and can be inserted into the interior of the grid tube (13e) by the operation of the moving unit (130) described later.

[0063] The storage unit (120) can be divided into multiple storage spaces so that multiple electromagnets (113) can be stably inserted and stored inside.

[0064] The aforementioned magnetic force application unit (110) can be moved while installed in the moving unit (130) and inserted into the interior of the grid tube (13e).

[0065] The mobile device (130) may include a mobile body (131) that is installed to be movable at a work site, and an insertion fixing part (133) that is installed on the mobile body (131) and fixes the magnetic force applying part (110).

[0066] The moving body (131) is installed so as to be movable by receiving a predetermined driving force from the work site, and can be installed so as to be movable while the magnetic force applying unit (110) is fixed.

[0067] An insertion fixing part (133) for fixing the magnetic force applying part (110) can be installed in this moving body (131).

[0068] The insertion fixing part (133) can be installed on one side of the moving body (131) and fixed with the fixing pipe (111a) of the magnetic force applying part (110) inserted inside.

[0069] Accordingly, the magnetic force application unit (110) is stably moved while installed on the moving unit (130), so that the electromagnet (113) can be inserted and fixed inside the grid tube (13e).

[0070] Meanwhile, by the operation of the magnetic force application unit (110) and the moving unit (130) described above, the shielding balls (13c) inside the terminal shield (13) can be separated into low-level and medium-level states and stored in the storage rack (150).

[0071] Here, the low-level shield ball (13c) can be separated from the terminal shield (13) by the extractor (140).

[0072] The extractor (140) can be installed inside the terminal shield (13) in the direction of the calandria tube sheet (13b) to extract a plurality of shield balls (13c) in a low-level state to the outside of the terminal shield (13).

[0073] The extractor (140) may include a magnetic member that applies a magnetic force to extract the shield ball (13c) inside the terminal shield (13). Alternatively, the extractor (140) may also include a vacuum suction device that provides suction pressure for extracting the terminal shield (13).

[0074] The extractor (140) can be installed so that the terminal shield (13) can be selectively inserted into the interior of the terminal shield (13) in the direction of the calandria tube sheet (13b) or the direction of the fueling tube sheet (13a), thereby enabling proper collection of the terminal shield (13) in a low-level or medium-level state.

[0075] FIG. 9 is a schematic drawing of a storage rack according to one embodiment of the present invention.

[0076] As illustrated in Fig. 9, the storage rack (150) has a plurality of compartment spaces formed therein, and can store a plurality of shielding balls (13c) separately according to low-level and medium-level states. Alternatively, the storage rack (150) can be installed in multiple units to store a plurality of shielding balls (13c) separately according to low-level and medium-level states.

[0077] As described above, the shielding ball separation device (100) of the present embodiment can separate a plurality of shielding balls (13c) installed inside the terminal shield (13) into low-level and medium-level states and store them separately in a storage rack (150). Therefore, stable processing of radioactive waste materials such as medium-level shielding balls is possible, and processing work can be performed in a state where worker exposure to radiation is minimized and safety is ensured during the radioactive waste processing process.

[0078] In addition, since the shield ball processing work can be fully automated, human accidents and work schedules can be minimized, effectively reducing dismantling work costs.

[0079] In addition, it is possible to separate the shielding balls (13c) from the terminal shield (13) by location and separate them into intermediate-level and low-level radioactive waste according to the classified computer simulation radiation evaluation results, thereby enabling efficient radioactive waste management.

[0080] Figure 10 is a flowchart schematically illustrating a shield ball separation method according to one embodiment of the present invention. The same reference numbers as in Figures 1 to 9 denote identical or similar components with identical or similar functions. Detailed descriptions of identical reference numbers are omitted below.

[0081] First, the magnetic force application part (110) is inserted into the inside of the grid tube (13e) in the direction of the fueling tube sheet (13a) (S10).

[0082] (S10) In the step, the magnetic force applying unit (110) can be inserted into the interior of the end shield (13), i.e., the interior of the grid tube (13e), in the direction of the fueling tube sheet (13a) by the moving operation of the moving unit (130) while the magnetic force applying unit (110) is fixed to the moving unit (130).

[0083] Next, by applying magnetic force to the electromagnet of the magnetic force applying unit (110) of step (S10), the positions of the plurality of shielding balls (13c) located within a first distance from the fueling tube sheet (13a) are fixed (S20).

[0084] (S20) The first distance of the step may be within 200 mm from the calandria tube sheet (13b). (S20) The current position may be fixed by applying a magnetic force to a metal shielding ball (13c) located within 200 mm from the calandria tube sheet (13b).

[0085] Next, the extractor (140) is installed in the inner direction of the terminal shield (13), and a plurality of shielding balls (13c) positioned within a first distance from the calandria tube sheet (13b) and a plurality of shielding balls (13c) positioned at a distance greater than the first distance from the calandria tube sheet (13b) are separated and removed (S30).

[0086] (S30) Step is to separate and remove the shielding ball (13c) located within the first distance from the calandria tube sheet (13b) and the shielding ball (13c) located at a distance greater than the first distance from the calandria tube sheet (13b).

[0087] That is, the shielding ball (13c) located closer to the calandria tube sheet (13b) is in a relatively medium-level state, and the shielding ball (13c) located closer to the fueling tube sheet (13a) is in a low-level state. This is to separate and remove the shielding balls (13c) in the medium-level and low-level states.

[0088] (S30) Step changes the installation position of the extractor (140) so that the shielding ball (13c) located close to the fueling tube sheet (13a) and the shielding ball (13c) located close to the calandria tube sheet (13b) can be sequentially separated and collected.

[0089] Next, the separated shield ball (13c) of step (S30) is stored (S40).

[0090] That is, step (S40) can separate the low-level and medium-level shielding balls (13c) inside the terminal shielding body (13) and store them separately in the storage rack (150).

[0091] Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications can be made within the scope of the claims, the detailed description of the invention, and the attached drawings, and it is obvious that this also falls within the scope of the present invention.

Claims

1. A device for removing the shield balls from an end shield including a fueling tubesheet and a calandria tubesheet facing each other, a plurality of shield balls filling a space between the fueling tubesheet and the calandria tubesheet, and a lattice tube that penetrates the fueling tubesheet and is connected to the calandria tubesheet and is connected to the calandria tube, which is installed in a radioactive structure of a heavy water reactor facility, A magnetic force applying unit inserted into the interior of the grid tube in the direction of the fueling tube sheet and applying a magnetic force to fix the positions of the plurality of shielding balls located within a first distance from the calandria tube sheet; A moving device that moves the magnetic force applying unit in the direction of the grid tube; and A storage rack for separately storing the shielding balls located within a first distance from the calandria tube sheet and the shielding balls located at a distance greater than the first distance within the terminal shield; A shielding ball separation device including:

2. In paragraph 1, The above magnetic force application part is, A fixed part inserted and fixed into the above moving device; and An electromagnet installed on one side of the fixed portion and inserted into the interior of the grid tube to apply magnetic force to fix the positions of the plurality of shielding balls within a first distance from the calandria tube sheet; A shielding ball separation device including:

3. In paragraph 2, The above fixed part, A fixed pipe inserted and fixed into the above moving device; and An angle cylinder rotatably connecting the fixed pipe and the electromagnet; A shielding ball separation device including:

4. In paragraph 3, The above mobile device, A movable body installed so as to be moved at the work site; and An insert fixing part installed on the above moving body to fix the above fixed pipe; A shielding ball separation device including:

5. In paragraph 4, A shielding ball separation device further comprising a withdrawal device for withdrawing the plurality of shielding balls located at a first distance or more from the calandria tube sheet and moving and storing them in the storage rack.

6. In paragraph 5, The above first distance is a shield ball separation device, which is a distance of 200 mm from the calandria tube sheet. 7.(a) A step of inserting the magnetic force applying part of any one of the first to fifth clauses into the interior of the grid tube in the direction of the fueling tube sheet; (b) a step of applying a magnetic force to the electromagnet of the magnetic force applying unit of step (a) to fix the positions of the plurality of shielding balls located within a first distance from the calandria tube sheet; (c) a step of installing the extractor in the inner direction of the terminal shield, separating and removing the plurality of shielding balls located at a first distance or more from the calandria tube sheet and the plurality of shielding balls located within the first distance; and (d) a step of storing the separated shielding balls of step (c) in the storage rack; A method for separating a shield ball, comprising:

8. In paragraph 7, A method for separating a shield ball, wherein the first distance is a distance of 200 mm from the calandria tube sheet.

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