Chip collection device and method

Abstract

To improve safety against exposure in a chip collection device and method.SOLUTION: The underwater machining device includes an underwater pump for sucking chips generated by underwater machining of a reactor vessel or an in-reactor structure together with in-reactor water, a separator provided on a suction side of the underwater pump to separate the chips from the in-reactor water, and a recovery container detachably provided on the separator to store the chips separated from the in-reactor water by the separator.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to chip collection devices and methods. [Background technology]

[0002] In nuclear power plants, various structures of the reactor must be inspected periodically to ensure sufficient safety and reliability. After various inspections are performed on the reactor structures, necessary parts are repaired. During repair work on the inner surface of the reactor vessel or the reactor internal structures, radioactive chips are generated by cutting work, and it is necessary to safely collect the generated chips. Technologies for collecting chips include those described in Patent Documents 1 and 2, for example. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Unexamined Patent Publication No. 59-129643 [Patent Document 2] Patent No. 3827874 Summary of the Invention [Problem to be solved by the invention]

[0004] The chip collection device includes a collection hose, a pump, and a filter. The chip collection device operates the pump to apply suction to the collection hose, sucking chips from the water into the collection hose and collecting them in the filter. In this case, the chips sucked into the collection hose pass through the pump, which can become clogged. Therefore, it is considered to attach a separator to the collection hose to collect the chips. However, since chips are radioactive waste generated by cutting the inner surface of the reactor vessel or key parts of the reactor internals, there is a possibility of workers being exposed to radiation when processing the separator that collects the radioactive waste chips.

[0005] The present disclosure is intended to solve the above-mentioned problems, and aims to provide a chip collection device and method that improves safety against radiation exposure. [Means for solving the problem]

[0006] In order to achieve the above-mentioned objectives, the chip collection device of the present disclosure comprises an underwater pump that sucks in chips generated by underwater processing of a reactor vessel or reactor internal structures together with reactor water, a separator provided on the suction side of the underwater pump that separates the chips from the reactor water, and a collection container that is detachably provided on the separator and contains the chips separated from the reactor water by the separator.

[0007] In addition, the chip collection method disclosed herein includes the steps of using an underwater pump to suck in chips generated by underwater processing of a reactor vessel or reactor internal structures together with reactor water, separating the chips from the sucked in reactor water using a separator, storing the chips separated from the reactor water by the separator in a collection container, stopping the underwater pump, and removing the collection container containing the chips from the separator and closing the connection to the separator with a lid member. [Effects of the Invention]

[0008] The chip collection device and method disclosed herein can improve safety against radiation exposure. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a block diagram showing the chip collection device of this embodiment. [Figure 2] FIG. 2 is a schematic diagram showing the chip collection device of this embodiment. [Figure 3] FIG. 3 is a vertical cross-sectional view of the collection container. [Figure 4] FIG. 4 is a schematic diagram showing the chip collecting method of this embodiment. [Figure 5] FIG. 5 is a schematic diagram showing the chip collecting method of this embodiment. [Figure 6] FIG. 6 is a schematic diagram showing the chip collecting method of this embodiment. [Figure 7] FIG. 7 is a schematic diagram showing the chip collecting method of this embodiment. [Figure 8] FIG. 8 is a vertical cross-sectional view of a collection container illustrating the chip collection method of this embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Preferred embodiments of the present disclosure will be described in detail below with reference to the drawings. Note that the present disclosure is not limited to these embodiments, and when there are multiple embodiments, the present disclosure also includes configurations that combine the embodiments. Furthermore, the components in the embodiments include those that can be easily imagined by a person skilled in the art, those that are substantially identical, and those that are within the so-called equivalent range.

[0011] <Outline of chip collection device> FIG. 1 is a block diagram showing the chip collection device of this embodiment.

[0012] The chip collection device 10 has a submersible pump 11, a separator 12, a collection container 13, and a wastewater treatment device 14. In the chip collection device 10, the separator 12 is connected to the suction side of the submersible pump 11, and the wastewater treatment device 14 is connected to the discharge side of the submersible pump 11. In addition, in the chip collection device 10, a cutting device (processing device) 15 is connected upstream of the separator 12.

[0013] A first suction hose (suction piping) 21 is connected to the suction side of the separator 12, and the cutting device 15 is connected via the first suction hose 21. The upstream end of the first suction hose 21 may not be connected to the cutting device 15, but may instead have a suction section at the upstream end, with the suction section being located near the cutting device 15. A second suction hose (suction piping) 22 is connected to the suction side of the submersible pump 11, and the separator 12 is connected via the second suction hose 22. A discharge hose (discharge piping) 23 is connected to the discharge side of the submersible pump 11, and the wastewater treatment device 14 is connected via the discharge hose 23.

[0014] The cutting device 15 is capable of underwater cutting of the inner surface of the reactor vessel 111 or key parts of the reactor internals 112 (see FIG. 4 ), which generates chips (activated chips) from the reactor vessel 111 and the reactor internals 112. The submersible pump 11 sucks in chips from the reactor vessel 111 and the reactor internals 112 together with reactor water through a first suction hose 21, a separator 12, and a second suction hose 22. The separator 12 separates the chips from the reactor water sucked in through the first suction hose 21. The recovery container 13 is detachably attached to the separator 12. The recovery container 13 stores the chips separated from the reactor water by the separator 12.

[0015] The wastewater treatment device 14 treats the in-furnace water from which the chips have been separated by the separator 12. Specifically, the wastewater treatment device 14 collects foreign matter such as fine chips that could not be separated by the separator 12. The wastewater treatment device 14 has, for example, a filter 14a and a strainer 14b (see FIG. 4).

[0016] <Specific configuration of chip collection device> FIG. 2 is a schematic diagram showing the chip collection device of this embodiment.

[0017] As shown in Figure 2, the submersible pump 11 has a joint 31 on the suction side, to which a second suction hose 22 is connected. The submersible pump 11 also has a joint 32 on the discharge side, to which a discharge hose 23 is connected. Although not shown, the submersible pump 11 may have a motor and impeller disposed therein, for example. The motor rotates the impeller of the submersible pump 11, generating a water flow from the suction side to the discharge side.

[0018] Separator 12 has a cylindrical portion 41 formed vertically above and a conical portion 42 formed conically below. Cylindrical portion 41 and conical portion 42 are formed integrally. Cylindrical portion 41 has an upper end closed by a ceiling portion 43, and conical portion 42 has an open lower end with a discharge portion 44. Separator 12 has a joint portion 45 on the suction side of cylindrical portion 41, and first suction hose 21 is connected to joint portion 45. Separator 12 also has a joint portion 46 on the discharge side of cylindrical portion 41, and second suction hose 22 is connected to joint portion 46.

[0019] The separator 12 has a baffle plate 47 disposed inside the cylindrical portion 41. The baffle plate 47 is disposed vertically, with its upper end connected to the ceiling portion 43 and its side connected to the cylindrical portion 41. The baffle plate 47 is disposed so as to face the joint portion 45 on the suction side and the joint portion 46 on the discharge side. The separator 12 also has an on-off valve 48 provided in the discharge portion 44.

[0020] Therefore, in the separator 12, the reactor water containing chips flows from the first suction hose 21 through the joint 45 into the cylindrical portion 41. The reactor water that has flowed into the cylindrical portion 41 collides with the baffle plate 47, and the chips contained in the reactor water descend due to gravity separation and flow toward the discharge portion 44. At this time, if the opening / closing valve 48 of the discharge portion 44 is open, the chips are collected from the discharge portion 44 into the collection container 13. Meanwhile, the reactor water from which the chips have been separated flows below the baffle plate 47 and is discharged from the joint 46 to the second suction hose 22.

[0021] The first suction hose 21 is arranged upstream of the submersible pump 11 and the separator 12, so that in-furnace water containing chips flows through it. Furthermore, the first suction hose 21 and the second suction hose 22 are arranged upstream of the submersible pump 11, so that suction pressure acts on them, creating a negative pressure state. On the other hand, the discharge hose 23 is arranged downstream of the submersible pump 11, so that in-furnace water not containing chips flows through it. Furthermore, the discharge hose 23 is arranged downstream of the submersible pump 11, so that discharge pressure acts on them, creating a negative pressure state.

[0022] Therefore, first suction hose 21 and second suction hose 22 are made of a material (for example, a polyurethane-based material) whose inner surface has higher slipperiness than discharge hose 23. On the other hand, discharge hose 23 is made of a material (for example, a polyvinyl chloride-based material) whose pressure resistance is higher than first suction hose 21 and second suction hose 22.

[0023] Additionally, the submersible pump 11 and the separator 12 are provided with tapered sections that reduce steps on the inner circumferential surfaces of the joints 31, 32, 45, 46 with the hoses (pipes) 21, 22, 23. For example, as shown in FIG. 2, the separator 12 is connected by fitting the end of the second suction hose 22 onto the outside of the joint 46. The joint 46 is provided with a tapered section 46a at its tip. The tapered section 46a may be flat or curved, and is a surface that seamlessly connects the inner surface of the joint 46 and the inner surface of the second suction hose 22.

[0024] <Configuration of collection container> FIG. 3 is a vertical cross-sectional view of the collection container.

[0025] 2 and 3, the collection container 13 has a container body 51 and a lid member 52. The container body 51 has a collection port (connecting portion) 61 to which the discharge portion 44 of the separator 12 is connected. A sealing member 62 such as an O-ring is attached to the collection port 61 of the container body 51. The container body 51 is made of a radiation shielding material. For example, iron or lead is used as the radiation shielding material, and the container body 51 has a wall portion with a predetermined thickness.

[0026] The lid member 52 is fixed to the container body 51 so as to close the recovery port 61 of the container body 51. The lid member 52 has a plug 63 and a lid body 64. The plug 63 and the lid body 64 are made of radiation shielding material. The plug 63 fits into the recovery port 61 of the container body 51, and can be waterproofed by the sealing member 62. The lid body 64 is disposed at the upper end of the container body 51, and can be fastened to the upper end of the container body 51 with a plurality of bolts (not shown). Fastening the lid body 64 to the upper end of the container body 51 prevents the plug 63 from falling off.

[0027] The recovery container 13 (container body 51) is provided with a discharge channel (discharge port) 71 for discharging reactor water at the bottom in the vertical direction. The discharge channel 71 is provided by penetrating the wall of the container body 51 from the inside to the outside. A drain pipe 72 is connected to the discharge channel 71 outside the container body 51, and an opening / closing valve 73 and a filter 74 are provided in the drain pipe 72.

[0028] The collection container 13 (container body 51) is provided with a supply channel (supply port) 75 for supplying dry gas at the top in the vertical direction. The supply channel 75 is provided so as to penetrate the wall of the container body 51 from the inside to the outside. A supply pipe 76 is connected to the supply channel 75 outside the container body 51, and an opening / closing valve 77 is provided on the supply pipe 76.

[0029] With the lid member 52 removed from the container body 51, the separator 12 and the collection container 13 are connected by fitting the discharge portion 44 of the separator 12 into the collection port 61. With the separator 12 and the collection container 13 in a connected state, chips separated by the separator 12 can be stored in the collection container 13. Meanwhile, with the discharge portion 44 of the separator 12 removed from the collection port 61, the collection container 13 is sealed by fitting the plug 63 into the collection port 61 of the container body 51 and fastening the lid body 64 to the container body 51. With the lid member 52 attached to the container body 51, the collection container 13 can store the collected chips as radioactive material in a shielded state.

[0030] However, the collection container 13 is not limited to this configuration. As shown in Fig. 3, the collection container may be a cage 13A having a mesh shape that can contain chips and allow furnace water to pass through. In this case, the cage 13A has an opening at the upper end, and the separator 12 is detachably connected to the cage 13A by inserting the discharge part 44 of the separator 12 into the opening. The cage 13A can be transported by being housed in a shielded container such as the collection container 13.

[0031] <Chip collection method> 4 to 7 are schematic diagrams showing the chip collecting method of this embodiment, and FIG. 8 is a vertical cross-sectional view of a collecting container showing the chip collecting method of this embodiment.

[0032] As shown in FIG. 4, a reactor building 101 is provided with a cavity 102 capable of storing cooling water, and a reactor vessel (reactor) 111 is suspended and supported by a reactor pool 103. A temporary equipment storage pool 104 is provided adjacent to the reactor pool 103 in the cavity 102. A crane device 105 is installed in the air in the reactor building 101. The reactor vessel lid is removed from the reactor vessel 111, exposing the reactor internals 112. A cutting device 15 performs repair work on the inner surface of the reactor vessel 111 and the reactor internals 112 underwater in the cavity 102. A chip recovery device 10 recovers chips from the reactor internals 112 that are generated during this process. For example, the cutting device 15 performs repair work on the reactor internal structure 112 that has been removed from the reactor vessel 111 into the cavity 102 and disassembled to a predetermined size, or performs repair work on the inner surface of the reactor vessel 111 from which the reactor internal structure 112 has been removed. Note that the following description will be given of a case where the cutting device 15 performs repair work on the reactor internal structure 112.

[0033] The submersible pump 11, separator 12, and collection container 13 that make up the chip collection device 10 are installed underwater in the cavity 102, the wastewater treatment device 14 is installed in the air in the reactor building 101, and the cutting device 15 is installed underwater near the reactor internals 112. The submersible pump 11, separator 12, wastewater treatment device 14, and cutting device 15 are connected by a first suction hose 21, a second suction hose 22, and a discharge hose 23. The collection container 13 is left with only the container body with the lid member 52 removed, and the separator 12 is attached.

[0034] When the cutting device 15 performs cutting work on the reactor internal structure 112 underwater in the cavity 102, chips are generated from the reactor internal structure 112. The chip collection device 10 operates the submersible pump 11 to suck the chips generated by the underwater machining of the reactor internal structure 112 together with the reactor water through the first suction hose 21. Then, the reactor water containing the chips sucked into the first suction hose 21 flows into the separator 12. The separator 12 separates the chips from the reactor water by gravity.

[0035] The chips separated from the reactor water by the separator 12 descend inside the separator 12 and are collected from the discharge section 44 into the collection container 13 by opening the on-off valve 48. At this time, the collection container 13 contains the chips and the reactor water. Meanwhile, the reactor water from which the chips have been separated is discharged into the second suction hose 22, passes through the submersible pump 11, and flows into the wastewater treatment device 14. The wastewater treatment device 14 reprocesses the reactor water and returns it to the cavity 102.

[0036] The capacity of the collection container 13 is set according to the radiation dose of the chips. When the radiation dose of the chips stored in the collection container 13 reaches a set value, the collection container 13 is replaced. As shown in FIG. 5, first, the operation of the submersible pump 11 is stopped. Next, the on-off valve 48 is closed, and then the first suction hose 21 and the second suction hose 22 are removed from the separator 12. In this state, the separator 12 is lifted using the crane device 105 and removed from the collection container 13. The removed separator 12 is transported by the crane device 105 and supported on a temporary storage stand in the temporary equipment storage pool 104.

[0037] As shown in FIG. 6, a lid member 52 is transported by a crane apparatus 105 to the recovery container 13 from which the separator 12 has been removed, and the lid member 52 is fastened to the container body 51 to seal the recovery container 13. The sealed recovery container 13 is transported by the crane apparatus 105 and placed in the air of the reactor building 101. Then, as shown in FIG. 7, a new, empty recovery container 13 (container body 51) is transported by the crane apparatus 105 and installed in the cavity 102. Next, the separator 12 supported on the temporary equipment storage pool 104 is transported by the crane apparatus 105 and attached to the recovery container 13 (container body 51) in the cavity 102. In this state, the submersible pump 11 is operated, and chip collection work is resumed.

[0038] As shown in FIG. 8 , the collection container 13 placed in the air drains the furnace water W therein and dries the chips C. The drying of the chips C may also be performed underwater. The on-off valve 73 provided on the drain pipe 72 of the collection container 13 is opened, and the on-off valve 77 provided on the supply pipe 76 is also opened. An air supply device (not shown) is then connected to the supply pipe 76 (on-off valve 77) and activated to supply dry air from the supply pipe 76 (on-off valve 77) through the supply path 75 into the collection container 13. This increases the internal pressure of the collection container 13, forcing the furnace water into the drain path 71 and then through the drain pipe 72, the on-off valve 73, and the filter 74 to be discharged to the outside. The furnace water discharged from the collection container 13 is returned to the cavity 102.

[0039] Then, when all of the furnace water W inside the collection container 13 has been drained and the chips C have been dried, the air supply device is stopped, and the drying operation of the chips C is completed. Also, the on-off valve 73 provided on the drain pipe 72 of the collection container 13 is closed, and the on-off valve 77 provided on the supply pipe 76 is closed. Then, the collection container containing the chips C is carried out by the crane device 105 and stored in a designated storage facility.

[0040] [Effects of this embodiment] The chip recovery device of the first embodiment comprises an underwater pump 11 that sucks in chips generated by underwater processing of a reactor vessel 111 or an internal structure 112 together with reactor water, a separator 12 that is provided on the suction side of the underwater pump 11 and separates the chips from the reactor water, and a recovery container 13 that is detachably provided on the separator 12 and stores the chips separated from the reactor water by the separator 12.

[0041] In the chip collection device according to the first aspect, the submersible pump 11 is operated to suck in chips together with reactor water, and the separator 12 separates the chips from the reactor water, and the separated chips are stored in the collection container 13. Since the chips are radioactive waste, they are safely stored in the collection container 13. Because the separator 12 and the collection container 13 are detachable, the separator 12 can remove the collection container 13 containing the chips (radioactive waste), and store it in a safe storage location. As a result, safety against radiation exposure can be improved.

[0042] The chip collection device according to the second aspect is the chip collection device according to the first aspect, and further, the collection container 13 is made of a radiation shielding material, which allows the chips, which are radioactive waste, to be collected safely.

[0043] The chip collection device according to the third aspect is the chip collection device according to the first or second aspect, and further includes collection container 13 having container body 51 with collection port 61 to which the separator is connected, and lid member 52 fixed to container body 51 so as to close collection port 61. This allows chips to be collected, contained, and stored appropriately.

[0044] The chip recovery device according to a fourth aspect is the chip recovery device according to any one of the first to third aspects, and further, recovery container 13 is provided with a discharge path (discharge port) 71 for discharging in-furnace water at a lower portion in the vertical direction, and discharge path 71 is provided with an on-off valve 73 and a filter 74. This allows the in-furnace water recovered inside recovery container 13 together with the chips to be discharged to the outside.

[0045] The chip recovery device according to the fifth aspect is the chip recovery device according to the fourth aspect, and further, recovery container 13 is provided with a supply path (supply port) 75 for supplying dry gas at the upper part in the vertical direction, and an opening / closing valve 77 is provided in supply path 75. This allows furnace water inside recovery container 13 to be quickly discharged to the outside.

[0046] The chip collecting device according to a sixth aspect is the chip collecting device according to any one of the first to fifth aspects, and further, the collecting container is a mesh-shaped basket 13A that contains chips and allows furnace water to pass through. This simplifies the collecting container.

[0047] The chip recovery device according to the seventh aspect is the chip recovery device according to any one of the first to sixth aspects, and further includes a wastewater treatment device 14 that treats the reactor water from which the chips have been separated by the separator 12. This makes it possible to suppress contamination of the reactor water that is returned to the cavity.

[0048] The chip collection device according to the eighth aspect is the chip collection device according to any one of the first to seventh aspects, and further comprises suction hoses (suction piping) 21, 22 connected to the suction side of the submersible pump 11, and the suction hoses 21, 22 have separators 12 disposed in their midsections, with the suction portions extending to the vicinity of the cutting position of the reactor vessel 111 or the reactor internal structure 112. Therefore, chips generated by the operation of the cutting device 15 can be properly collected by the suction hoses 21, 22.

[0049] The chip recovery device according to the ninth aspect is the chip recovery device according to any one of the first to eighth aspects, and further comprises submersible pump 11, with suction hoses (suction piping) 21, 22 connected to the suction side and discharge hose (discharge piping) 23 connected to the discharge side, and suction hoses 21, 22 made of a material with a higher inner surface slipperiness than discharge hose 23. This allows the in-furnace water containing chips to flow stably.

[0050] The chip collection device according to the tenth aspect is the chip collection device according to any one of the first to ninth aspects, and further comprises a submersible pump 11, with suction hoses (suction piping) 21, 22 connected to the suction side and a discharge hose (discharge piping) 23 connected to the discharge side, the discharge hose 23 being made of a material with higher pressure resistance than the suction hoses 21, 22. Therefore, damage to the discharge hose 23 can be suppressed and the submersible pump 11 can properly move the chips.

[0051] The chip recovery device according to an eleventh aspect is the chip recovery device according to any one of the first to tenth aspects, and further includes tapered sections that reduce steps on the inner circumferential surfaces of the joints 31, 32, 45, 46 of the submersible pump 11 and the separator 12 with the hoses (pipes) 21, 22, 23. This allows the chips and furnace water to flow stably.

[0052] The chip collection method according to the twelfth aspect includes the steps of: sucking chips generated by underwater machining of a reactor vessel 111 or a reactor internal structure 112 together with reactor water using a submersible pump 11; separating the chips from the sucked reactor water using a separator 12; storing the chips separated from the reactor water by the separator 12 in a collection container 13; stopping the submersible pump 11; and removing the collection container 13 containing the chips from the separator 12 and closing the collection port (connecting portion) 61 with a lid member 52. This allows the separator 12 to remove the collection container 13 containing the chips (radioactive waste) and store it in a safe storage location. As a result, safety against radiation exposure can be improved. [Explanation of symbols]

[0053] 10. Chip collection device 11 Submersible pump 12 Separator 13 Collection container 14 Wastewater treatment equipment 15 Cutting equipment 21 First suction hose (suction piping) 22 Second suction hose (suction piping) 23 Discharge hose (discharge piping) 31,32 Joint 41 Cylindrical part 42 Cone section 43 Ceiling 44 Discharge section 45,46 Joint 46a Tapered section 47 Baffle plate 51 Container body 52 Cover member 61 Collection port (connection) 62 Sealing material 63 Plug 64 Lid body 71 Discharge channel (discharge port) 72 Drain pipe 73 On-off valve 74 filters 75 Supply channel (supply port) 76 Supply pipe 77 On-off valve 101 Reactor Building 102 Cavity 103 Reactor Pool 104 Temporary Equipment Storage Pool 105 Crane equipment 111 Reactor Vessel 112 Furnace internals

Claims

1. a submersible pump that sucks in chips generated by underwater processing of the reactor vessel or reactor internals together with reactor water; a separator provided on the suction side of the submersible pump to separate chips from the furnace water; a collection container detachably provided on the separator for storing chips separated from the furnace water by the separator; A chip collection device equipped with:

2. The collection container is made of a radiation shielding material. The chip recovery device according to claim 1.

3. The collection container includes a container body having a collection port to which the separator is connected, and a lid member fixed to the container body so as to close the collection port. The chip recovery device according to claim 1.

4. the recovery container is provided with a discharge port for discharging reactor water at a lower portion in a vertical direction, and an on-off valve and a filter are provided at the discharge port; The chip recovery device according to claim 1.

5. The recovery container has a supply port for supplying dry gas at an upper portion in a vertical direction, and an on-off valve is provided at the supply port. The chip recovery device according to claim 4.

6. The collection container has a mesh shape that accommodates chips and allows furnace water to pass through. The chip recovery device according to claim 1.

7. A wastewater treatment device is provided to treat the water in the furnace from which the chips have been separated by the separator. The chip recovery device according to claim 1.

8. The submersible pump has a suction pipe connected to its suction side, the separator is disposed in the middle of the suction pipe, and the suction portion is extended to the vicinity of the cutting position. The chip recovery device according to claim 1.

9. The submersible pump has a suction pipe connected to the suction side and a discharge pipe connected to the discharge side, and the suction pipe is made of a material having a higher inner surface slip resistance than the discharge pipe. The chip recovery device according to claim 1.

10. The submersible pump has a suction pipe connected to its suction side and a discharge pipe connected to its discharge side, and the discharge pipe is made of a material with higher pressure resistance than the suction pipe. The chip recovery device according to claim 1.

11. The submersible pump and the separator are provided with a tapered portion that reduces a step on the inner circumferential surface of the joint portion with the piping. The chip recovery device according to claim 1.

12. a step of sucking chips generated by underwater machining of the reactor vessel or reactor internals together with reactor water by a submersible pump; Separating chips from the sucked in furnace water by a separator; collecting the chips separated from the furnace water by the separator into a collection container; stopping the submersible pump; removing the collection container containing the chips from the separator and closing a connection portion between the collection container and the separator with a lid member; A chip recovery method comprising:

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