Method and apparatus for recovering radioactive waste

Abstract

To provide a method and apparatus for collecting radioactive waste, which simplify radioactive waste collection work to aim for improvement in workability of the collection work.SOLUTION: A radioactive waste collection method for collecting radioactive waste including fuel melt-solidified inside a nuclear reactor containment vessel is provided, the method comprising filling a collection container with cooling water containing radioactive waste, dewatering the radioactive waste filling the collection container, and closing off the radioactive waste dewatered in the collection container.SELECTED DRAWING: Figure 1

Description

Technical Field

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[0001] The present disclosure relates to a method and an apparatus for recovering radioactive waste formed by melting core fuel.

Background Art

[0002] For example, in a nuclear power plant, when the core fuel disposed inside a reactor pressure vessel melts, the structures inside the reactor containment vessel also melt and solidify, becoming debris as radioactive waste. Therefore, it is necessary to recover and process radioactive waste such as debris from the reactor containment vessel. As a technique for recovering debris inside the reactor containment vessel, for example, there is one described in Patent Document 1 below.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The technique described in Patent Document 1 is to crush the debris inside the reactor containment vessel, recover the debris together with water, and hold it on a filter for recovery. However, Patent Document 1 does not describe a specific method for treating the debris held on the filter. Further, the technique of Patent Document 1 requires replacement of the filter for recovering the debris.

[0005] The present disclosure solves the above-described problems, and an object thereof is to provide a method and an apparatus for recovering radioactive waste that improve the workability of the recovery operation by simplifying the recovery operation of radioactive waste.

Means for Solving the Problems

[0006] A radioactive waste recovery method of this disclosure for achieving the above objectives is a radioactive waste recovery method for recovering radioactive waste including fuel that has been molten and solidified inside a reactor containment vessel, comprising the steps of: filling a recovery container with cooling water containing the radioactive waste; dewatering the radioactive waste filled in the recovery container; and closing the recovery container to seal off the radioactive waste that has been dewatered.

[0007] Furthermore, the radioactive waste recovery apparatus of this disclosure is a radioactive waste recovery apparatus for recovering radioactive waste including fuel that has been molten and solidified inside a reactor containment vessel, and comprises a filling device for filling a recovery container with cooling water containing the radioactive waste, a dewatering device for dewatering the radioactive waste filled in the recovery container, and a closing device for closing the radioactive waste that has been dewatered in the recovery container. [Effects of the Invention]

[0008] The radioactive waste recovery method and apparatus described herein can improve the efficiency of the recovery work by simplifying the radioactive waste recovery process. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a schematic diagram illustrating the radioactive waste recovery method according to the first embodiment. [Figure 2] Figure 2 is a cross-sectional view of the internal collection container. [Figure 3] Figure 3 is a cross-sectional view of the external collection container. [Figure 4] Figure 4 is a schematic diagram showing the main components of a radioactive waste recovery device. [Figure 5] Figure 5 is a schematic diagram illustrating the process from filtration and dewatering of debris to storage in the radioactive waste recovery method. [Figure 6] Figure 6 is a schematic diagram illustrating the process from drying to transport of radioactive waste in the recovery method. [Figure 7] Figure 7 is a schematic diagram showing the processing line in a radioactive waste recovery method. [Figure 8] Figure 8 is a schematic diagram showing a modified processing line in a radioactive waste recovery method. [Figure 9] Figure 9 is a schematic diagram representing a boiling water reactor. [Figure 10] Figure 10 is a schematic diagram showing the process from debris processing to filling in the radioactive waste recovery method of the second embodiment. [Figure 11] Figure 11 is a schematic diagram illustrating the debris filling process in the radioactive waste recovery method. [Figure 12] Figure 12 is a schematic diagram illustrating the filtration and dewatering treatment of debris in the radioactive waste recovery method. [Figure 13] Figure 13 is a schematic diagram illustrating the storage and processing of debris in radioactive waste recovery methods. [Figure 14] Figure 14 is a schematic diagram illustrating the drying process of debris in radioactive waste recovery methods. [Figure 15] Figure 15 is a schematic diagram illustrating the hydrogen generation measurement process and weight measurement process of debris in a radioactive waste recovery method. [Figure 16] Figure 16 is a schematic diagram illustrating the process from debris containment to transportation in the radioactive waste recovery method. [Figure 17] Figure 17 is a schematic diagram showing a modified example of the process from debris processing to filling in a radioactive waste recovery method. [Modes for carrying out the invention]

[0010] Preferred embodiments of the present disclosure will be described in detail below with reference to the drawings. However, these embodiments do not limit the present disclosure, and where there are multiple embodiments, they may be combinations of these embodiments. Furthermore, the components in the embodiments include those readily conceivable by those skilled in the art, those that are substantially identical, and those that are equivalent.

[0011] [First Embodiment] <Boiling water reactor> Figure 9 is a schematic diagram showing a boiling water reactor.

[0012] As shown in Figure 9, the boiling water reactor 100 is configured such that a reactor 102 is housed inside a reactor containment vessel 101. The reactor containment vessel 101 is installed inside a reactor building 103 and is sealed by attaching an upper lid 104 to its upper end. The reactor containment vessel 101 has a dry well 105 formed inside and a plurality of pressure suppression chambers 106 formed inside with a pressure suppression pool filled with cooling water. The dry well 105 is connected to the pressure suppression chambers 106 via a vent passage 107, and the tip of the vent passage 107 is immersed in the cooling water of the pressure suppression pool.

[0013] The reactor building 103 supports the reactor containment vessel 101, and a plurality of shield plugs 108 that are divided into a plurality of parts above the upper lid 104 and function as radiation shields are arranged. The reactor containment vessel 101 is hermetically held by the plurality of shield plugs 108.

[0014] The reactor 102 is composed of a reactor vessel 110 to which an upper lid 109 is attached, a reactor core 111 loaded with a plurality of fuel assemblies containing nuclear fuel material, a steam separator 112, a steam dryer 113, and the like. The reactor core 111, the steam separator 112, and the steam dryer 113 are arranged inside the reactor vessel 110. A core shroud 114 is arranged inside the reactor vessel 110 and surrounds the reactor core 111. The reactor core 111 is loaded with a plurality of fuel assemblies inside, and each fuel assembly is supported at its lower end by a core support plate 115 and held at its upper end by an upper grid plate 116. The steam separator 112 is arranged above the upper grid plate 116, and the steam dryer 113 is arranged above the steam separator 112.

[0015] Multiple control rods 117 are arranged to be inserted into the reactor core 111 from below. The multiple control rods 117 are located within control rod guide tubes (not shown) and are movable vertically, and are moved in and out between fuel assemblies located inside the reactor core 111 to control the reactor output. A control rod drive mechanism 118 is attached to the lower end of the reactor vessel 110 and is connected to each control rod 117 in the control rod guide tube.

[0016] The reactor vessel 110, as a core structure, contains not only the core 111 but also a steam-water separator 112, a steam dryer 113, a core shroud 114, a core support plate 115, an upper grid plate 116, control rods 117, and other components arranged inside.

[0017] The reactor vessel 110 is installed on a cylindrical pedestal 120, which is placed on a concrete mat 119 located at the bottom of the reactor containment vessel 101. A cylindrical gamma-ray shield 121 is then installed at the upper end of the pedestal 120, surrounding the outside of the reactor vessel 110.

[0018] Incidentally, in a nuclear power plant, if the core 111 and other parts inside the reactor vessel 110 melt, the molten fuel and other molten materials accumulate at the bottom of the reactor vessel 110, or the reactor vessel 110 itself melts and falls onto the concrete mat 119. The reactor containment vessel 101 is cooled by the supply of cooling water to its interior, and the molten materials are cooled and solidified by the cooling water stored in the pedestal 120. The solidified molten materials are subject to recovery as radioactive waste (hereinafter referred to as debris) M.

[0019] The radioactive waste treatment device 130 is used for investigating and recovering debris M located inside the reactor containment vessel 101. The reactor building 103 has the reactor containment vessel 101 supporting the reactor 102 (reactor vessel 110) in the center, and a room 131 is provided outside the reactor containment vessel 101. Room 131 is a space that workers can safely enter without exposure to radiation when the reactor 102 is operating normally. Room 131 is partitioned by concrete walls 132. Room 131 has a work opening 134 that penetrates the concrete structural wall and communicates with the inside of the reactor containment vessel 101.

[0020] The radioactive waste treatment device 130 is installed in room 131 in the reactor building 103. The radioactive waste treatment device 130 has an enclosure 140. The enclosure 140 is connected to the working opening (penetration) 134 of the reactor containment vessel 101 via a connecting pipe 135. The recovery device 10 is located inside the enclosure 140.

[0021] <Outline of methods for recovering radioactive waste> The radioactive waste recovery method and apparatus of the first embodiment involves processing the debris M inside the reactor containment vessel 101, filling a recovery container with cooling water containing the debris M, transporting the recovery container filled with cooling water containing the debris M from inside the reactor containment vessel 101 to outside the reactor containment vessel 101, and performing various treatments on the debris M inside the enclosure 140.

[0022] Figure 1 is a schematic diagram illustrating the radioactive waste recovery method according to the first embodiment.

[0023] As shown in Figure 1, the radioactive waste recovery method includes processing 11, filling 12, filtration and dewatering 13, storage 14, drying 15, hydrogen generation amount measurement 16, weight measurement 17, sealing 18, and transport 19.

[0024] Processing 11 is a process in which the debris M is processed by a processing device inside the reactor containment vessel 101. The processing device is, for example, a cutting device or a crushing device, which cuts or crushes the debris M to produce granular material.

[0025] The filling process 12 is a process of filling a recovery container with cooling water containing the debris M processed by the processing device. In the first embodiment, the debris M is processed inside the reactor containment vessel 101, a pump device acting as a filling device is activated, and the cooling water containing the debris M is filled into the recovery container.

[0026] Filtration and dewatering treatment 13 is a process for dewatering the debris M filled in the recovery container. The recovery container, filled with cooling water containing the debris M, is transported by a conveying device to the enclosure 140 (see Figure 9) of the reactor containment vessel 101. The debris M inside the recovery container is filtered and dewatered using a filtration device and a dewatering device installed inside the enclosure 140.

[0027] The collection container comprises an inner collection container and an outer collection container. The filling process 12 fills the inner collection container with cooling water containing the debris M processed by the processing device. The storage process 14 stores the inner collection container, which is filled with cooling water containing the debris M, into the outer collection container, for example, using a conveyor or a work robot.

[0028] Drying treatment 15 is a process to dry the debris M that has been dehydrated in the recovery container. Drying treatment 15 dries the debris M by removing moisture using a heating device, a vacuum device, or other drying equipment.

[0029] The hydrogen generation measurement process 16 is a process for measuring the amount of hydrogen generated from the debris M that has been dried in the recovery container. Since the debris M contains nuclear fuel material, hydrogen is generated when residual moisture and organic matter are decomposed by radiation from the debris M itself. In the hydrogen generation measurement process 16, the amount of hydrogen generated from the debris M in the recovery container is measured using a hydrogen meter. If the amount of hydrogen generated from the debris M exceeds a predetermined regulatory value, it is preferable to perform the drying process 15 again.

[0030] Weight measurement process 17 is a process for measuring the weight of debris M that has been dried in the recovery container. Since debris M contains nuclear fuel material, it is necessary to limit its storage to a volume (weight) that will not cause criticality, and to control the amount that can be transported to the outside. Weight measurement process 17 measures the weight of debris M in the recovery container using a weighing scale.

[0031] Closing process 18 is the process of covering the recovery container containing the debris M, whose hydrogen generation amount and weight have been measured. The recovery container has an outer recovery container, which has a container body and a lid. Closing process 18 is performed, for example, by using a work robot to place the inner recovery container containing the debris M into the container body of the outer recovery container, and then attaching the lid to the container body to close it.

[0032] The transport process 19 involves sealing the debris M contained in the recovery container by the sealing process 18 into a transport container, storing it there, and transporting it to the outside. The recovery container containing the debris M is then stored in a designated processing facility after the transport process 19.

[0033] <Collection container> Figure 2 is a cross-sectional view of the inner collection container, and Figure 3 is a cross-sectional view of the outer collection container.

[0034] As shown in Figures 2 and 3, the recovery container 20 has an inner recovery container 21 and an outer recovery container 31. The inner recovery container 21 is filled with cooling water containing debris M. The outer recovery container 31 houses the inner recovery container 21. The outer recovery container 31 stores the debris M by housing the inner recovery container 21 containing the debris M.

[0035] As shown in Figure 2, the internal recovery container 21 comprises a container body 22, a first filter 23, and a second filter 24. The container body 22 has a hollow box shape. The container body 22 has a filling port 22a at the top and a drain port 22b at the bottom. A ring-shaped sealing member 22c is fixed to the outer circumference of the filling port 22a, and a ring-shaped sealing member 22d is fixed to the outer circumference of the drain port 22b. When a cooling water supply pipe and discharge pipe are connected to the internal recovery container 21, water leakage is prevented by the sealing members 22c and 22d. In addition, since the drain port 22b is used for dewatering from the internal recovery container 21, multiple drain ports 22b may be provided. A plate-shaped guide member 25 is arranged inside the container body 22, facing the filling port 22a. A flow path 26 is formed between the top of the container body 22 and the guide member 25.

[0036] The first filter 23 filters the cooling water containing debris M. The second filter 24 filters the cooling water containing debris M that has been filtered by the first filter 23. The first filter 23 is located inside the container body 22, below the guide member 25. The first filter 23 filters the cooling water that has flowed through the flow path 26 from the filling port 22a. Furthermore, the guide member 25 prevents clogging of the first filter 23 by ensuring that the cooling water containing debris M flows along the surface of the first filter 23. Note that when cooling water containing large-grained debris M flows, the guide member 25 may not be provided in order to ensure a wide flow path 26. The second filter 24 is located inside the container body 22, below the first filter 23, and closes the drain port 22b. The first filter 23 is preferably composed of at least one of a wedge wire screen, a bag filter, or a mesh filter. The second filter 24 is preferably composed of filter paper. However, the configuration is not limited to a first filter 23 and a second filter 24; it is sufficient if the filtration performance (beta value β) of the second filter 24 is higher than that of the first filter 23.

[0037] As shown in Figure 3, the outer collection container 31 has a container body 32 and a lid 33. The container body 32 has a hollow box shape with an opening 34 formed at the top. The container body 32 has a volume large enough to accommodate the inner collection container 21. The lid 33 has a flat plate shape. The lid 33 is attached to the container body 32 over the opening 34 to close the opening 34 and close the inside of the container body 32. In addition, the outer collection container 31 is provided with a guide 35 inside. The guide 35 guides the lower outer circumference of the inner collection container 21, allowing the inner collection container 21 to be positioned in the center of the outer collection container 31. Therefore, positioning of the inner collection container 21 relative to the outer collection container 31 during operations such as removal and transport can be easily performed.

[0038] <Radioactive waste recovery device> Figure 4 is a schematic diagram showing the main components of the radioactive waste recovery device, Figure 5 is a schematic diagram showing the process from filtration and dewatering of debris to storage in the radioactive waste recovery method, and Figure 6 is a schematic diagram showing the process from drying of debris to transport in the radioactive waste recovery method.

[0039] As shown in Figures 4 to 6, the recovery device 10 includes a processing device 41, a filling device 42, a filtration / dewatering device 43, a storage device 44, a drying device 45, a hydrogen generation amount measuring device 46, a weight measuring device 47, a closing device 48, and a conveying device 49.

[0040] As shown in Figure 4, the recovery unit 50 includes a processing device 41, a filling device 42, a filtration / dewatering device 43, and an internal recovery container 21. The unit body 51 has the processing device 41 located at its lower part. The processing device 41 includes a housing 41a and a processing tool 41b. The housing 41a separates the interior from the exterior, and the processing tool 41b is supported inside so as to be rotatable or linearly movable. The processing tool 41b can process the debris M by rotating or moving linearly, and is preferably composed of a cutter, grinding wheel, chisel, hammer, etc. The housing 41a can accommodate the processed granular debris M together with cooling water.

[0041] The unit body 51 is equipped with an internal recovery container 21 at its top. The internal recovery container 21 is located inside the unit body 51. The unit body 51 is equipped with a filling device 42. The filling device 42 has a water supply pipe 42a, a recovery pipe 42b, and a pump 42c. The water supply pipe 42a supplies cooling water, which will become processing water, from outside the unit body 51 to the cutting portion of the debris M by the processing tool 41b inside the housing 41a of the processing device 41. The recovery pipe 42b is equipped with a pump 42c. By driving the pump 42c, cooling water containing the debris M near the cutting portion of the debris M by the processing tool 41b inside the unit body 51 is supplied to the internal recovery container 21 via the recovery pipe 42b. As the cooling water inside the housing 41a of the processing device 41 is discharged via the recovery pipe 42b, the cooling water is drawn into the housing 41a via the water supply pipe 42a. The internal recovery container 21 is filled with cooling water containing debris M when cooling water is supplied from the recovery pipe 42b.

[0042] The filtration and dewatering device 43 is provided in the internal recovery container 21. The filtration and dewatering device 43 consists of a drain port 22b, a first filter 23, and a second filter 24 (see Figure 2) provided in the internal recovery container 21. The internal recovery container 21 is located inside the unit body 51, and the drain port 22b communicates with the outside. The internal recovery container 21 is also movable relative to the unit body 51 and is detachable. A moving device 52 is provided in the unit body 51 and can move the internal recovery container 21 between an internal position and an external position of the unit body 51. When the moving device 52 moves to the external position, the internal recovery container 21, which is inside the unit body 51, is discharged from the unit body 51 and removed. The filtration and dewatering device 43 may be provided separately from the internal recovery container 21 and located outside.

[0043] As shown in Figure 5, the recovery unit 50 is transported to the enclosure 140, where the internal recovery container 21 is removed from the unit body 51. Maintenance and replacement work is performed inside the enclosure 140 on the recovery unit 50, which includes the processing device 41 and the filling device 42. The recovery unit 50 is placed on the transport platform 53, and the internal recovery container 21 is moved to an external position relative to the unit body 51 by the moving device 52 and removed, so that it is placed on the transport platform 53.

[0044] The transport platform 53 is provided with a drainage section 54, and a roller conveyor 55 is provided on the drainage section 54. The internal recovery container 21 is placed on the roller conveyor 55 such that the drain port 22b is located vertically downward. As the internal recovery container 21 moves along the drainage section 54 on the roller conveyor 55, the cooling water inside is filtered by its own weight as it passes through the first filter 23 and the second filter 24. As the cooling water is drained from the drain port 22b into the drainage section 54, the granular debris M remains inside the internal recovery container 21 and is dewatered. Alternatively, pressure may be applied to the cooling water inside the internal recovery container 21 by applying compressed air or compressed gas from the filling port 22a of the internal recovery container 21, thereby filtering the cooling water inside as it passes through the first filter 23 and the second filter 24.

[0045] The transport platform 53 is provided with a storage section 56, and a roller conveyor 57 is provided in the storage section 56. The transport platform 53 is capable of loading the outer recovery container 31 into the storage section 56. The transport platform 53 is equipped with a work robot (crane) 58 as a storage device 44. The work robot 58 holds and moves the inner recovery container 21 located in the drainage section 54, and transports the inner recovery container 21 above the outer recovery container 31 located in the storage section 56. At this point, the inner recovery container 21 is lowered by the moving device 52, moving into the interior of the outer recovery container 31.

[0046] As shown in Figure 6, the transport table 53 is provided with a drying section 59. The drying section 59 has a first drying section 59a consisting of a lid 60 that can be opened and closed at the top, piping 61, and a vacuum pump 62, and a second drying section 59b consisting of a heating device (e.g., heater) 63. By operating the vacuum pump 62, the drying section 59 is depressurized and the inside is dried. The heating device 63 heats the inner recovery container 21 via the outer recovery container 31 and dries the inside. The inside of the drying section 59 is contaminated by the evaporation of cooling water containing debris M, so a cleaning device may be provided inside the drying section 59. Alternatively, it may consist of either the first drying section 59a or the second drying section 59b.

[0047] The transport platform 53 is equipped with a measuring section 64, and a roller conveyor 65 is provided extending downstream from the measuring section 64. The measuring section 64 is equipped with a stopper 67 operated by a drive device 66, which stops the outer recovery container 31 at the measuring section 64. The measuring section 64 is also equipped with a closing lid 68 that is movable by a moving device 69 above it. The outer recovery container 31, which houses the inner recovery container 21, stops at the measuring section 64. At this point, the closing lid 68 is lowered by the moving device 69, closing the opening of the outer recovery container 31. Then, the amount of hydrogen generated from the debris M inside the inner recovery container 21 is measured by a hydrogen meter, which is a hydrogen generation amount measuring device 46. When the measurement of the amount of hydrogen generated from the debris M is completed, the closing lid 68 is raised by the moving device 69. In addition, the weight of the debris M inside the inner recovery container 21 is measured by a weighing scale, which is a weight measuring device 47. Once the measurement of the amount of hydrogen generated and the weight of the debris M is complete, the drive unit 66 lowers the stopper 67, moving the external recovery container 31.

[0048] The transport platform 53 is provided with a closing section 70. The closing section 70 is equipped with a stopper 72 that is operated by a drive device 71, which stops the outer recovery container 31 at the closing section 70. The transport platform 53 is capable of carrying the lid 33 into the closing section 70. The outer recovery container 31, which contains the inner recovery container 21, stops at the closing section 70. At this point, the work robot, acting as a closing device 48, holds the lid 33 and attaches the lid 33 to the outer recovery container 31 containing the inner recovery container 21, thereby containing the inner recovery container 21, i.e., the debris M. Once the closing process for the debris M is complete, the drive device 71 lowers the stopper 72, and the outer recovery container 31 moves.

[0049] The transport platform 53 is equipped with a transport section 73. The transport section 73 transports the recovery container 20 to the external container 74 using a work robot or a transport conveyor as a transport device 49. The recovery container 20 transported to the external container 74 is sealed by placing a lid on the external container 74 and then transported outside the enclosure 140.

[0050] <Recovery line for recovery device> Figure 7 is a schematic diagram showing the processing line in a radioactive waste recovery method, and Figure 8 is a schematic diagram showing a modified version of the processing line in a radioactive waste recovery method.

[0051] As shown in Figure 7, the recovery device 10 is provided with a container loading line L2, a lid loading line L3, and an external transport line L4 that intersect the main transport line L1 horizontally. The main transport line L1, the container loading line L2, the lid loading line L3, and the external transport line L4 are, for example, composed of roller conveyors capable of transporting the recovery containers 20 horizontally.

[0052] The main transport line L1 consists of a drainage section 54, a storage section 56, a drying section 59, a measuring section 64, a closing section 70, and a transport section 73, all arranged in a straight line horizontally. The container loading line L2 is a line that loads the outer recovery container 31 into the storage section 56 along the horizontal direction. The lid loading line L3 is a line that loads the lid 33 into the closing section 70 along the horizontal direction. The external transport line L4 is a line that transports the recovery container 20 to the outside along the horizontal direction.

[0053] The processing line is not limited to the configuration described above. As shown in Figure 8, the recovery device 10 is provided with a container loading line L12, a lid loading line L13, and an external transport line L14 that intersect the main transport line L11 in a vertical direction. The main transport line L11 is composed of, for example, a roller conveyor capable of transporting the recovery containers 20 in a horizontal direction. The container loading line L12, the lid loading line L13, and the external transport line L14 are composed of, for example, lifters capable of transporting the recovery containers 20 in a vertical direction.

[0054] The main transport line L11 consists of a drainage section 54, a storage section 56, a drying section 59, a measuring section 64, a closing section 70, and a transport section 73, all arranged in a straight line horizontally. The container loading line L12 is the line for loading the outer recovery container 31 into the storage section 56 from above in a vertical direction. The lid loading line L13 is the line for loading the lid 33 into the closing section 70 from above in a vertical direction. The external transport line L14 is the line for transporting the recovery container 20 to the outside along a horizontal direction. When the outer recovery container 31 and lid 33 are loaded from the outside, they are transported upward in a vertical direction and supplied to the container loading line L12 and the lid loading line L13.

[0055] [Second Embodiment] The radioactive waste recovery method and apparatus of the second embodiment has the same basic configuration as the radioactive waste recovery method and apparatus of the first embodiment. That is, as shown in Figure 1, it includes a processing process 11, a filling process 12, a filtration and dewatering process 13, a storage process 14, a drying process 15, a hydrogen generation amount measurement process 16, a weight measurement process 17, a sealing process 18, and a transport process 19.

[0056] However, the radioactive waste recovery method and apparatus of the second embodiment involves processing the debris M inside the reactor containment vessel 101, recovering the cooling water containing the debris M from inside the reactor containment vessel 101 to the enclosure 140 outside the reactor containment vessel 101, filling the cooling water containing the debris M into a recovery container, and performing various treatments on the debris M.

[0057] The second embodiment of the radioactive waste recovery method and apparatus will be described in detail below, but components having the same function as those in the first embodiment described above will be denoted by the same reference numerals and detailed descriptions will be omitted.

[0058] Figure 10 is a schematic diagram showing the process from debris processing to filling in the radioactive waste recovery method of the second embodiment.

[0059] As shown in Figure 10, the recovery device 10A includes a processing device 41, a filling device 42, a filtration / dewatering device 43, a storage device 44, a drying device 45, a hydrogen generation amount measuring device 46, a weight measuring device 47, a shut-off device 48, and a conveying device 49, in addition to a concentration device (concentration treatment) 80. The processing device 41, filling device 42, filtration / dewatering device 43, storage device 44, drying device 45, hydrogen generation amount measuring device 46, weight measuring device 47, shut-off device 48, and conveying device 49 are the same as in the first embodiment, and their description is omitted.

[0060] In the recovery device 10A, the processing device 41 is located inside the reactor containment vessel 101, while the other devices, including the enrichment device 80, are located in the enclosure 140. The processing device 41 has a housing 41a and a processing tool 41b. The filling device 42 has a feedwater pipe 42a, a recovery pipe 42b, and a pump 42c. The recovery pipe 42b is equipped with the pump 42c, its upstream side is connected to the processing device 41, and its downstream side is connected to the internal recovery container 21 via the enrichment device 80. That is, the recovery pipe 42b is laid from the reactor containment vessel 101 to the enclosure 140.

[0061] The concentration device 80 includes a first cyclone 81, a second cyclone 82, and a microbubble separator 83. The first cyclone 81 is connected to a first branch pipe 83a that branches off from the recovery pipe 42b, and the second cyclone 82 is connected to a second branch pipe 83b that branches off from the recovery pipe 42b. The first branch pipe 83a is equipped with a first on-off valve 84a, and the second branch pipe 83b is equipped with a second on-off valve 84b. Furthermore, the first cyclone 81 is connected to a first debris recovery pipe 86a that discharges the separated debris M at its lower end, and the second cyclone 82 is connected to a second debris recovery pipe 86b that discharges the separated debris M at its lower end. The first debris recovery pipe 86a is equipped with a first on-off valve 87a, and the second debris recovery pipe 86b is equipped with a second on-off valve 87b. Then, the first debris collection pipe 86a and the second debris collection pipe 86b converge downstream and are connected to the internal collection container 21.

[0062] Furthermore, the first cyclone 81 is connected to a first drain pipe 88a at its top for discharging separated cooling water, and the second cyclone 82 is connected to a second drain pipe 88b at its top for discharging separated cooling water. The first drain pipe 88a is equipped with a first on-off valve 89a, and the second drain pipe 88b is equipped with a second on-off valve 89b. The first drain pipe 88a and the second drain pipe 88b are then combined and connected to a microbubble separator 83.

[0063] The microbubble separator 83 separates the fine granular particles of debris M by supplying microbubbles to the cooling water mixed with debris M, causing the debris M to float to the surface. The microbubble separator 83 is connected to a third debris recovery pipe 86c at its top for discharging the separated debris M, and its downstream side is connected to the internal recovery container 21. The third debris recovery pipe 86c is equipped with a third on-off valve 87c. The cooling water from which the debris M has been separated is returned to the reactor containment vessel 101. The debris recovery pipes 86a, 86b, and 86c are connected to a backwash pipe 90 equipped with an on-off valve 90a. A fourth on-off valve 87d is provided downstream of the confluence of the first debris recovery pipe 86a, the second debris recovery pipe 86b, and the third debris recovery pipe 86c.

[0064] In processing 11, the processing device 41 processes the debris M. In filling 12, the filling device 42 supplies cooling water containing the debris M to the concentration device 80. In the concentration process, the cooling water containing the debris M recovered through the recovery pipe 42b is supplied to the first cyclone 81 and the second cyclone 82. The first cyclone 81 and the second cyclone 82 separate the debris M from the cooling water by centrifugal separation. The separated debris M is filled into the internal recovery container 21 by the first debris recovery pipe 86a and the second debris recovery pipe 86b. Meanwhile, the cooling water from which the debris M has been separated is supplied to the microbubble separator 83 by the first drain pipe 88a and the second drain pipe 88b. The microbubble separator 83 supplies microbubbles to the cooling water to float and separate the fine granular particles of the debris M. Debris M, separated from the cooling water, is filled into the internal recovery container 21 via the third debris recovery pipe 86c. Meanwhile, the cooling water from which debris M has been separated is returned to the reactor containment vessel 101.

[0065] Figure 11 is a schematic diagram illustrating the debris filling process in the radioactive waste recovery method. As shown in Figure 11, in the filling process 12, the cooling water containing the debris M, which has been processed by the processing device 41 and concentrated by the concentration device 80, is filled into the internal recovery container 21.

[0066] Figure 12 is a schematic diagram illustrating the filtration and dewatering treatment of debris in the radioactive waste recovery method. As shown in Figure 12, in the filtration and dewatering treatment 13, the cooling water containing the debris M, which is filled into the internal recovery container 21, is filtered and dewatered within the internal recovery container 21.

[0067] Figure 13 is a schematic diagram illustrating the debris storage process in the radioactive waste recovery method. As shown in Figure 13, in the storage process 14, the inner recovery container 21, which is filled with cooling water containing the debris M, is moved into the outer recovery container 31 by a work robot or the like and stored inside.

[0068] Figure 14 is a schematic diagram illustrating the drying process of debris in a radioactive waste recovery method. As shown in Figure 14, in the drying process 15, the cooling water containing the debris M filled in the inner recovery container 21 is dried by heating and depressurizing it through the outer recovery container 31.

[0069] Figure 15 is a schematic diagram illustrating the hydrogen generation measurement process and weight measurement process of debris in the radioactive waste recovery method. As shown in Figure 15, in the hydrogen generation measurement process 16, the amount of hydrogen generated by the debris M stored in the internal recovery container 21 is measured by a hydrogen meter. In addition, in the weight measurement process 17, the weight of the debris M stored in the internal recovery container 21 is measured by a weighing scale.

[0070] Figure 16 is a schematic diagram illustrating the process from debris containment to transport in the radioactive waste recovery method. As shown in Figure 16, in containment process 18, the inner recovery container 21 containing the debris M is placed inside the outer recovery container 31 and the lid 33 is fixed and closed. Subsequently, in transport process 19, the debris M contained in the recovery container 20 is transported to the outside.

[0071] Note that the enrichment device 80 is not limited to the configuration described above. Figure 17 is a schematic diagram showing a modified example of the process from debris processing to filling in the radioactive waste recovery method.

[0072] As shown in Figure 17, the concentration device 80A includes a first cyclone 81, a second cyclone 82, a microbubble separator 83, a storage tank 91, and a belt conveyor 92. The first cyclone 81, the second cyclone 82, and the microbubble separator 83 are configured as described above. The storage tank 91 has an open top and an inclined shape. The first debris recovery pipe 86a, the second debris recovery pipe 86b, and the downstream side of the third debris recovery pipe 86c are connected to the top of the storage tank 91. A belt conveyor 92 is provided in the storage tank 91. The belt conveyor 92 transports the debris M that settles in the storage tank 91 to the outside.

[0073] During the concentration process, the cooling water containing the debris M recovered through the recovery pipe 42b is supplied to the first cyclone 81 and the second cyclone 82. The first cyclone 81 and the second cyclone 82 separate the debris M from the cooling water by centrifugal separation. The separated debris M is transported to the storage tank 91 by the first debris recovery pipe 86a and the second debris recovery pipe 86b. Meanwhile, the cooling water from which the debris M has been separated is supplied to the microbubble separator 83 by the first drain pipe 88a and the second drain pipe 88b. The microbubble separator 83 supplies microbubbles to the cooling water to float and separate the fine granular particles of the debris M. The debris M separated from the cooling water is transported to the storage tank 91 by the third debris recovery pipe 86c. The belt conveyor 92 transports the debris M settling in the storage tank 91 to the outside and fills it into the internal recovery container 21.

[0074] [Effects of this embodiment] The first embodiment of the method for recovering radioactive waste includes the steps of: filling a recovery container 20 with cooling water containing debris (radioactive waste) M; dewatering the debris M filled in the recovery container 20; and closing the recovery container 20 to remove the dewatered debris M.

[0075] According to the radioactive waste recovery method of the first embodiment, the debris M inside the reactor containment vessel 101 is recovered together with the cooling water and filled into the recovery container 20 in a filling process 12. After the debris M is filled into the recovery container 20, the debris M is subjected to a filtration and dewatering process 13 and a sealing process 18. Then, after being filled into the recovery container 20, the debris M is subjected to disposal, storage, or analysis. Therefore, the efficiency of the recovery work can be improved by simplifying the radioactive waste recovery process.

[0076] The second embodiment of the radioactive waste recovery method is the first embodiment of the radioactive waste recovery method, further comprising measuring the amount of hydrogen generated from the dehydrated debris M in the recovery container 20. This ensures safety.

[0077] The third embodiment of the radioactive waste recovery method is the radioactive waste recovery method according to the first or second embodiment, further comprising dewatering the debris M filled in the recovery container 20 and then drying the debris M. This can accelerate the drying of the debris M.

[0078] The fourth aspect of the radioactive waste recovery method is the third aspect of the radioactive waste recovery method, further comprising measuring the weight of the debris M dried in the recovery container 20. This makes it possible to control the amount of debris M filled in the recovery container 20.

[0079] The fifth embodiment of the radioactive waste recovery method is the first or second embodiment of the radioactive waste recovery method, further comprising an inner recovery container 21 filled with cooling water containing debris M and an outer recovery container 31 that houses the inner recovery container 21, and the debris M is contained by housing the inner recovery container 21 in the outer recovery container 31. This makes it possible to easily carry out the debris M containment work. In addition, it is possible to minimize the spread of contamination to the outside of the outer recovery container 31.

[0080] The sixth embodiment of the radioactive waste recovery method is a radioactive waste recovery method according to any one of the first to fifth embodiments, further comprising an internal recovery container 21 having a container body 22 with a filling port 22a and a drain port 22b, and filters 23 and 24 for filtering the cooling water containing the debris M. This allows filtration and dewatering to be performed simply by filling the internal recovery container 21 with the cooling water containing the debris M, thereby improving work efficiency.

[0081] The radioactive waste recovery method according to the seventh embodiment is a radioactive waste recovery method according to the sixth embodiment, further comprising a first filter 23 for filtering the cooling water containing debris M, and a second filter 24 for filtering the cooling water containing debris M filtered by the first filter 23. This allows for proper filtration and dewatering simply by filling the cooling water containing debris M into the internal recovery container 21.

[0082] The eighth aspect of the radioactive waste recovery method is a radioactive waste recovery method according to any one of the first to fourth aspects, further comprising processing the debris M inside the reactor containment vessel 101 and filling the recovery container 20 with cooling water containing the debris M. This eliminates the need to transport the cooling water containing the debris M to the outside of the reactor containment vessel 101, thus eliminating the need for drainage facilities.

[0083] The radioactive waste recovery method according to the ninth aspect is the radioactive waste recovery method according to the fifth aspect, further comprising removing the recovery container 20 filled with cooling water containing debris M from inside the reactor containment vessel 101 to outside the reactor containment vessel 101, and then dewatering the debris M. This makes it possible to remove the debris M easily and safely.

[0084] The radioactive waste recovery method according to the tenth embodiment is a radioactive waste recovery method according to any one of the first to ninth embodiments, further comprising processing the debris M inside the reactor containment vessel 101, recovering the cooling water containing the debris M to the outside of the reactor containment vessel 101, and then filling the cooling water containing the debris M into a recovery container 20. This eliminates the need to transport the recovery container 20, which is filled with the cooling water containing the debris M, between the reactor containment vessel 101 and the enclosure 140, thus eliminating the need for transport equipment.

[0085] The radioactive waste recovery method according to the 11th embodiment is a radioactive waste recovery method according to any one of the first to seventh embodiments, further comprising concentrating the cooling water containing debris M recovered outside the reactor containment vessel 101, and then filling the recovery container 20 with the cooling water containing debris M. This reduces the amount of cooling water to be filled into the recovery container 20, and simplifies the filtration / dewatering process 13 and the drying process 15.

[0086] The radioactive waste recovery device according to the 12th embodiment comprises a filling device 42 for filling a recovery container 20 with cooling water containing debris M, a filtration / dewatering device 43 for dewatering the debris M filled in the recovery container 20, and a closing device 48 for closing the recovery container 20 to stop the dewatered debris M.

[0087] According to the radioactive waste recovery device of the 12th embodiment, the debris M inside the reactor containment vessel 101 is recovered together with the cooling water and filled into the recovery container 20. After the debris M is filled into the recovery container 20, the debris M is filtered, dewatered, and the container is sealed. Then, after being filled into the recovery container 20, the debris M is subjected to disposal, storage, or analysis. Therefore, the efficiency of the recovery work can be improved by simplifying the radioactive waste recovery process.

[0088] In the embodiments described above, the radioactive waste recovery method includes a processing process 11, a filling process 12, a filtration / dewatering process 13, a storage process 14, a drying process 15, a hydrogen generation amount measurement process 16, a weight measurement process 17, a sealing process 18, and a transport process 19, but is not limited to this configuration. The radioactive waste recovery method only needs to include at least a filling process 12, a filtration / dewatering process 13, and a sealing process 18. However, it is preferable that the radioactive waste recovery method includes a weight measurement process 17.

[0089] Furthermore, in the embodiments described above, the order of each process in the radioactive waste recovery method is not limited to each embodiment. For example, the storage process 14 may be performed simultaneously with or before the closure process 18. [Explanation of Symbols]

[0090] 10,10A Recovery device 11. Processing 12. Filling process 13. Filtration and dehydration process 14. Storage Processing 15. Drying process 16. Hydrogen generation amount measurement process 17. Weight measurement process 18 Closing process 19. Conveying process 20 Collection containers 21 Internal collection container 31 External collection container 41 Processing equipment 42 Filling equipment 43 Filtration / dehydration equipment 44 Storage device 45 Drying equipment 46. ​​Hydrogen generation amount measuring device 47 Weight measuring device 48 Closing device 49 Conveying device 80,80A concentrator 101 Reactor containment vessel 130. Radioactive waste disposal equipment 140 Enclosure M Debris (radioactive waste)

Claims

1. In a method for recovering radioactive waste, which recovers radioactive waste containing molten and solidified fuel inside a reactor containment vessel, A step of filling a recovery container with cooling water containing the aforementioned radioactive waste, A step of dewatering the radioactive waste filled in the collection container, A step of drying the radioactive waste that has been filled into the collection container and dewatered, A step of sealing the dewatered radioactive waste in the aforementioned collection container, It has, The aforementioned recovery container comprises an inner recovery container filled with cooling water containing the radioactive waste, and an outer recovery container that houses the inner recovery container. Dewatering is performed on the internal recovery container which is filled with cooling water containing the radioactive waste. After dewatering, the inner recovery container is placed in the outer recovery container. The inner recovery container is dried while it is stored inside the outer recovery container. The radioactive waste is sealed off by attaching a lid to the external collection container. Methods for collecting radioactive waste.

2. The amount of hydrogen generated from the radioactive waste dehydrated in the aforementioned recovery container is measured. The method for recovering radioactive waste according to claim 1.

3. The weight of the radioactive waste dried in the aforementioned collection container is measured. The method for recovering radioactive waste according to claim 1.

4. The aforementioned internal recovery container comprises a container body having a filling port and a drain port, and a filter for filtering the cooling water containing the radioactive waste. The method for recovering radioactive waste according to claim 1.

5. The filter comprises a first filter for filtering the cooling water containing the radioactive waste, and a second filter for filtering the cooling water containing the radioactive waste that has been filtered by the first filter. The method for recovering radioactive waste according to claim 4.

6. The radioactive waste is processed inside the reactor containment vessel, and the cooling water containing the radioactive waste is filled into the recovery container. The method for recovering radioactive waste according to claim 1.

7. After the recovery container, which is filled with cooling water containing the radioactive waste, is removed from inside the reactor containment vessel to outside the reactor containment vessel, the radioactive waste is dewatered. The method for recovering radioactive waste according to claim 6.

8. After processing the radioactive waste inside the reactor containment vessel and recovering the cooling water containing the radioactive waste to the outside of the reactor containment vessel, the cooling water containing the radioactive waste is filled into the recovery container. The method for recovering radioactive waste according to claim 1.

9. After concentrating the cooling water containing the radioactive waste recovered outside the reactor containment vessel, the cooling water containing the radioactive waste is filled into the recovery container. The method for recovering radioactive waste according to claim 1.

10. In a radioactive waste recovery device that recovers radioactive waste, including fuel that has molten and solidified inside the reactor containment vessel, A filling device for filling a recovery container with cooling water containing the aforementioned radioactive waste, A dewatering device for dewatering the radioactive waste filled in the aforementioned collection container, A drying apparatus for drying the radioactive waste that has been filled into the collection container and dewatered, A closing device for sealing the radioactive waste that has been dewatered in the aforementioned collection container, Equipped with, The aforementioned recovery container comprises an inner recovery container filled with cooling water containing the radioactive waste, and an outer recovery container that houses the inner recovery container. The dewatering device dewaters the internal recovery container, which is filled with cooling water containing the radioactive waste. The drying apparatus performs drying after dewatering, with the inner recovery container stored in the outer recovery container. The sealing device seals the radioactive waste by attaching a lid to the external collection container. A device for collecting radioactive waste.

11. The system includes a hydrogen generation amount measurement process for measuring the amount of hydrogen generated from the radioactive waste that has been dewatered in the aforementioned recovery container. A radioactive waste recovery device according to claim 10.

12. The collection container has a weight measuring device for measuring the weight of the radioactive waste that has been dried in the collection container. A radioactive waste recovery device according to claim 10.

13. The aforementioned internal recovery container comprises a container body having a filling port and a drain port, and a filter for filtering the cooling water containing the radioactive waste. A radioactive waste recovery device according to claim 10.

14. The filter comprises a first filter for filtering the cooling water containing the radioactive waste, and a second filter for filtering the cooling water containing the radioactive waste that has been filtered by the first filter. A radioactive waste recovery device according to claim 13.

15. The radioactive waste is processed inside the reactor containment vessel, and the cooling water containing the radioactive waste is filled into the recovery container. A radioactive waste recovery device according to claim 10.

16. After the recovery container, which is filled with cooling water containing the radioactive waste, is removed from inside the reactor containment vessel to outside the reactor containment vessel, the radioactive waste is dewatered. A radioactive waste recovery device according to claim 15.

17. After processing the radioactive waste inside the reactor containment vessel and recovering the cooling water containing the radioactive waste to the outside of the reactor containment vessel, the cooling water containing the radioactive waste is filled into the recovery container. A radioactive waste recovery device according to claim 10.

18. After concentrating the cooling water containing the radioactive waste recovered outside the reactor containment vessel, the cooling water containing the radioactive waste is filled into the recovery container. A radioactive waste recovery device according to claim 10.

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