JP6338446B2 - Fuel debris retrieval device and fuel debris retrieval method - Google Patents

Description

  The present invention relates to a fuel debris retrieval device and a fuel debris retrieval method, and more particularly to a fuel debris retrieval device and a fuel debris retrieval method suitable for application to a boiling water nuclear power plant.

  In a nuclear power plant such as a boiling water nuclear power plant and a pressurized water nuclear power plant, a sealed fuel assembly containing a nuclear fuel material is loaded into a core in a reactor pressure vessel. The fuel assembly loaded in the core is taken out of the reactor pressure vessel as a spent fuel assembly after experiencing the operation of the nuclear power plant in a predetermined number of operation cycles from the time of loading in the core. Instead of the spent fuel assembly, a new fuel assembly having a burnup of 0 GWd / t is loaded into the core in the reactor pressure vessel.

  For example, in a boiling water nuclear power plant, an emergency core cooling device having multiple cooling systems is provided so that each fuel assembly loaded on the core in the reactor pressure vessel is always cooled. . The installation of an emergency core cooling system prevents the occurrence of core melting accidents. However, although the probability is very low, the function of the emergency core cooling device may be lost, and the fuel assembly loaded in the core may be melted. Studies have been conducted on a method for taking out the molten nuclear fuel material when the fuel assembly is melted.

  Japanese Patent Application Laid-Open No. 2013-19875 describes a method for taking out molten nuclear fuel material from a reactor pressure vessel in an atmospheric environment using a boring device attached to a support device installed in the reactor pressure vessel. . In this molten nuclear fuel material removal method, two work houses are stacked and placed on the operation floor of the reactor building so as to cover the reactor well, and a shield plug is installed on the operation floor so as to cover the reactor well, Using a boring device installed on the shield plug, the reactor containment head, the top cover of the reactor pressure vessel, and the steam dryer and steam separator in the reactor pressure vessel are perforated. The state of the core is observed by a camera inserted into the core through this hole, and when the fuel assembly in the core is melted, a granular radiation shield is filled into the core through the hole.

  Thereafter, the reactor containment vessel head surrounding the reactor pressure vessel is cut by a cutting device arranged in the work house. The cut head is carried out. The top cover of the reactor pressure vessel is also removed. Further, the steam dryer and the steam separator in the reactor pressure vessel are also carried out after being cut by a cutting device arranged in the work house.

  In the method for taking out the molten nuclear fuel material described in Japanese Patent Application Laid-Open No. 2013-19875, a support device provided with a boring device is inserted into a reactor pressure vessel, and this support device is installed on the inner surface of the reactor pressure vessel. The support device has a circular base, a turntable, four cylinders, and a slide base. The turntable is pivotally attached to the upper surface of the base, and the four cylinders are attached to the side surface of the base at equal intervals in the circumferential direction. A piston rod is attached to the piston disposed in each cylinder, and a pressing member is attached to the tip of each piston rod. Two guide rails are installed on the upper surface of the turntable and extend in the radial direction of the turntable. A slide base is movably attached to the guide rail, and a boring device is attached to the upper surface of the slide base.

  A support device installed with a boring device, suspended from an overhead crane installed in the lower work house installed on the operation floor, is lowered to a predetermined position in the reactor pressure vessel, and four cylinders To press the pressing member at the tip of each piston rod against the inner surface of the reactor pressure vessel. As a result, the support device is held on the inner surface of the reactor pressure vessel. Thereafter, the molten nuclear fuel material present at the bottom of the reactor pressure vessel is taken out using a boring device.

  FIG. 37 of Japanese Patent No. 5249176 describes a robot arm that bends in all directions.

JP 2013-19875 A Japanese Patent No. 5249176

  In the method for taking out the molten nuclear fuel material described in Japanese Patent Application Laid-Open No. 2013-19875, the turntable of the support device installed in the reactor pressure vessel is directed from the center of the turntable toward the outer peripheral surface of the turntable. An elongated through hole is formed in the radial direction. A cutting device of a boring device installed on the slide base extends below the turntable through the through hole. When the molten nuclear fuel material present at the bottom of the reactor pressure vessel is being taken out using the boring device, radioactive dust is placed between the through holes and the circular base and the inner surface of the reactor pressure vessel. There is a risk of rising through the formed annular gap and reaching the work house installed on the operation floor.

  The air in the work house is purified by a ventilation air conditioning system provided in the work house to remove radioactive dust that has reached the work house. In order to inspect and repair the failed equipment in the work house, an operator needs to enter the work house. Although the radioactive dust is removed by the ventilation air conditioning system, if the radioactive dust adheres to the inner surface of the work house or the like, there is a possibility of being exposed by radiation from the radioactive dust.

  For this reason, in order to prevent molten nuclear fuel material by the boring device, specifically, radioactive dust generated by cutting fuel debris from rising to the work house, gaps formed between the constituent members constituting the above-described support device, and a circular shape It is conceivable to seal an annular gap formed between the base of the reactor and the inner surface of the reactor pressure vessel.

  However, since the reactor pressure vessel is a welded structure, even if an annular sealing member is attached to the side surface of the circular base of the support device, an annular ring formed between the circular base and the inner surface of the reactor pressure vessel is formed. It is difficult to completely seal the gap with the annular sealing member.

  An object of the present invention is to provide a fuel debris retrieval device and a fuel debris retrieval method that can suppress the outflow of radioactive dust from a reactor pressure vessel during the recovery of fuel debris.

In order to achieve the above object, the present invention is characterized in that a base portion, a first working arm having a cutting tool and a second working arm having a gripping tool provided on the base portion, and a lower end portion are attached to the base portion. And a cylindrical expansion / contraction seal member with a fixing member attached to the upper end thereof, and an opening into which the gripping tool of the second work arm is inserted is located below the base portion on the side wall. The storage container holding member that holds the storage container that is formed and disposed inside is attached to the base portion and extends downward from the base portion .

Since it has a cylindrical expansion / contraction seal member with a fixing member attached to the upper end, the fixing member can be attached to the upper end of the reactor pressure vessel while maintaining airtightness when collecting fuel debris. A space between the base portion and the fixing member located in the furnace pressure vessel can be sealed with an expansion seal member. For this reason, the outflow of the radioactive dust which goes upwards from a reactor pressure vessel can be suppressed. Further, a storage container holding portion for holding a storage container in which an opening into which the gripping tool of the second work arm is inserted is formed on the side wall below the base portion and is disposed inside is attached to the base portion. Since the storage container can be held in the storage container holding member, the cut piece of the fuel debris that is the cut object can be gripped by the grip of the second work arm. And can be easily stored in the storage container through the opening.

  According to the present invention, it is possible to suppress the outflow of radioactive dust from the reactor pressure vessel during the recovery of fuel debris.

It is a longitudinal cross-sectional view of the reactor building of a boiling water nuclear power plant. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a configuration diagram of a fuel debris retrieval device according to embodiment 1, which is a preferred embodiment of the present invention. The storage container storing the fuel debris pieces cut by the fuel debris cutting tool of the fuel debris retrieval device shown in FIG. 2 is raised to above the swivel table of the fuel debris retrieval device through the passage in the storage container holding member of the fuel debris retrieval device. It is explanatory drawing which shows the state made to do. It is explanatory drawing which shows the state which closed the channel | path in a storage container holding member, after raising a storage container to the upper direction of a turning table. It is explanatory drawing which shows the state which pulls up the carrying-out container which accommodated the storage container. It is explanatory drawing which shows the cutting state of the fuel debris by the fuel debris extraction device lowered to near the bottom of the reactor pressure vessel. It is explanatory drawing which shows the fuel debris extraction method of Example 2 which is another suitable Example of this invention. It is a block diagram of the fuel debris extraction apparatus of Example 3 which is another suitable Example of this invention. It is a block diagram of the fuel debris extraction apparatus of Example 4 which is another suitable Example of this invention. It is explanatory drawing which shows cutting of the fuel debris using the fuel debris extraction apparatus shown in FIG. It is a block diagram of the fuel debris extraction apparatus of Example 5 which is another suitable Example of this invention. It is an enlarged view of the XII part of FIG. It is explanatory drawing which shows the state of the sealing apparatus when the fuel debris holding tool shown by FIG. 12 is pulled up. It is a XIV-XIV arrow line view of FIG. It is XV-XV sectional drawing of FIG. It is XVI-XVI sectional drawing of FIG. It is a block diagram of the fuel debris extraction apparatus of Example 6 which is another suitable Example of this invention. It is an enlarged view of the X section of FIG. It is explanatory drawing which shows the connection and descent | fall of the seal | sticker cylindrical part of the fuel debris extraction apparatus shown in FIG.

  Examples of the present invention will be described below.

  A fuel debris retrieval device according to embodiment 1, which is a preferred embodiment of the present invention, will be described with reference to FIG.

  A schematic configuration of a boiling water nuclear power plant in which fuel debris is extracted using the fuel debris extraction device of the present embodiment will be described with reference to FIG.

  The boiling water nuclear power plant 1 includes a nuclear reactor 2 and a reactor containment vessel 17. The reactor containment vessel 17 is installed in the reactor building 22, and a head 18 as an upper lid is attached to an upper end portion of the reactor containment vessel 17 and is sealed. The reactor containment vessel 17 has a dry well 19 formed inside and a pressure suppression chamber 20 in which a pressure suppression pool filled with cooling water is formed. One end of the vent passage communicated with the dry well 19 is immersed in the cooling water of the pressure suppression pool in the pressure suppression chamber 20.

  A shield plug 28, which is a radiation shield divided into a plurality of parts, is disposed immediately above the head 18, and these shield plugs 28 are disposed in the reactor well 24 and installed on the operation floor 23 of the reactor building 22. ing. An equipment temporary storage pool (dryer separator pool) 25 and a fuel storage pool 26 are disposed adjacent to the reactor well 24 and surrounded by the operation floor 23. The temporary storage pool 25 and the reactor well 24 and the fuel storage pool 26 and the reactor well 24 are partitioned by a removable gate member (not shown), respectively.

  The nuclear reactor 2 includes a reactor pressure vessel 3 configured with an upper lid 4 attached thereto, a reactor core 7 loaded with a plurality of fuel assemblies 8 including nuclear fuel materials, a steam separator 11 and a steam dryer 12. ing. The core 7, the steam / water separator 11, and the steam dryer 12 are disposed in the reactor pressure vessel 3. A core shroud 6 installed in the reactor pressure vessel 3 surrounds the core 7. Each fuel assembly 8 loaded in the core 7 has a lower end supported by the core support plate 9 and an upper end held by the upper lattice plate 10. The steam / water separator 11 is disposed above the upper lattice plate 10 located at the upper end of the core 7, and the steam dryer 12 is disposed above the steam / water separator 11.

  A plurality of control rod guide tubes 13 are arranged below the core support plate 9 in the reactor pressure vessel 3. Control rods (not shown) that are taken in and out between the fuel assemblies 8 in the core 7 and control the reactor power are arranged in the control rod guide tubes 13. A plurality of control rod drive mechanism housings 14 are attached to the lower mirror portion 5 of the reactor pressure vessel 3. A control rod drive mechanism (not shown) is installed in each control rod drive mechanism housing 14 and connected to the control rod in the control rod guide tube 13.

  The core shroud 6, the core support plate 9, the upper lattice plate 10, the steam separator 11, the steam dryer 12, and the control rod guide tube 13 installed in the reactor pressure vessel 3 are reactor internal structures.

The reactor pressure vessel 3 is mounted on a cylindrical pedestal 15 provided on the concrete mat 16 provided on the bottom of the reactor containment vessel 1 in 7. A cylindrical γ-ray shield 21 is installed at the upper end of the pedestal 15 and surrounds the reactor pressure vessel 3.

In such a boiling water nuclear power plant 1, in a state where the reactor is scrammed and the reactor power is reduced, all the power sources for supplying the current of the boiling water nuclear power plant 1 are temporarily lost and used in an emergency. Assume that a situation has occurred in which the core cooling system has not been activated. When all the power supplies are lost and the pumps of the emergency core cooling system do not operate and the cooling of the fuel rods included in the fuel assemblies 8 in the core 7 is impaired, the fuel rods The contained nuclear fuel material is melted, and the structural members of the fuel assembly 8, such as the fuel rod cladding, the channel box of the fuel assembly 8, the upper tie plate, and the lower tie plate are melted by the melting of the nuclear fuel material. The fuel debris 35, which is a melt of nuclear fuel material and structural members of the fuel assembly 8, may fall onto the inner surface of the lower mirror portion 5 that is the bottom of the reactor pressure vessel 3. In some cases, the fuel debris 35 includes a melt of a reactor internal structure such as the core support plate 9. The molten fuel debris 35 is cooled and solidified.

  In the event that such fuel debris 35 falls to the bottom of the reactor pressure vessel 3, the solidified fuel debris 35 is carried out of the reactor pressure vessel 3. Decommissioning treatment is carried out for the boiling water nuclear power plant 1 that has fallen.

  Next, the configuration of the fuel debris retrieval device 40 of this embodiment will be described with reference to FIG. The fuel debris retrieval device 40 includes a base portion 41, a turning table 42, a telescopic seal member 44, a plurality of clamp devices 45, work arms 48 </ b> A and 48 </ b> B, a pair of work arm drive devices 49, and a ring-shaped fixing member 57. . The base part 41 and the turning table 42 are made of a radiation shielding material. Both the working arms 48A and 48B have a robot arm structure having two actuator units 200 'described in FIG. 37 of Japanese Patent No. 5249176, for example. The working arm 48A has a cutting tool 36 attached to the tip of the robot arm. The work arm 48B has a gripping tool 37 attached to the tip of the robot arm.

The turning table 42 is attached to the ring-shaped base portion 41 using a bearing 50 so as to be turnable. Between the inner surface of the outer surface and the base portion 41 of the turn table 42 above the bearing 50 is provided an annular sealing member 51A, while the turn table 42 and the base portion 41 by a bearing 5 0 is sealed. A seal member 51 </ b> B is also installed between the inner surfaces of the base portion 41 and the bearing 50 and the inner surface of the turning table 42. A plurality (e.g., eight) the clamping device 45 is attached to the lower surface of the turntable 4 2. The clamp device 45 includes a cylinder 46, a piston rod 47, and the like. The cylinder 46 is attached to the lower surface of the base portion 41, and the piston rod 47 is attached to a piston (not shown) disposed in the cylinder 46. The cylinder 46 and the piston rod 47 are arranged in the radial direction of the base portion 41. A pressing member is attached to the tip of the piston rod 47.

  A cylindrical support portion 65 is installed on the upper surface of the base portion 41. A plate-shaped ring member 43 is attached to the upper end of the cylindrical support portion 65. The inner diameter of the ring member 43 is smaller than the inner diameter of a fixing member 57 described later. The lower end of the bellows-like cylindrical expansion / contraction seal member 44 is attached to the upper surface of the ring member 43, and the upper end of the expansion / contraction seal member 44 is attached to the lower surface of the ring-shaped fixing member 57. The stretchable seal member 44 is configured by integrating an aramid fiber and a polyurethane sheet with an aramid fiber sandwiched between the polyurethane sheets. The cylindrical expansion / contraction seal member 44 has a bellows shape in the axial direction of the expansion / contraction seal member 44, and can expand and contract in the axial direction.

  The work arms 48 </ b> A and 48 </ b> B are separately inserted into two through holes formed in the turning table 42 and installed on the turning table 42. A cutting tool 36 is provided at the tip of the working arm 48A. A gripping tool 37 is provided at the tip of the work arm 48B. A work arm driving device 49 is separately attached to the upper end of each of the work arms 48A and 48B. The annular gaps between each of the work arms 48A and 48B and the turning table 42 are each sealed with a seal member (not shown). The turning table 42 is provided with a storage container holding member 54 in addition to the work arms 48A and 48B. The storage container holding member 54 has a bottom plate portion on which the storage container 55 is placed, and penetrates the turning table 42. The storage container holding member 54 is a portion facing the through hole on the side wall of the turning table 42, and an opening for inserting the work arm 48 </ b> B is formed between the bottom plate portion and the lower surface of the turning table 42. . The storage container holding member 54 is formed with a passage extending from the opening to the upper surface of the turntable 42. The shape of the cross section of the side wall of the storage container holding member 54 is an arc shape except for the opening at the position where the opening is formed. The carry-out container 56 is disposed immediately above the storage container holding member 54 and is removably attached to the upper surface of the turntable 42. A lower end portion of the carry-out container 56 is opened to a passage in the storage container holding member 54. A hoist (storage container transfer device) 66 is disposed in the carry-out container 56 and attached to the ceiling portion of the carry-out container 56. The passage in the storage container holding member 54 is covered and sealed by the carry-out container 56.

  A shutter member 53 made of a radiation shielding material is attached to the lower surface of the turntable 42 so as to be movable in the horizontal direction. The shutter member 53 opens and closes the passage in the storage container holding member 54. A pair of shutter members 52 made of a radiation shielding material are attached to the lower surface of the turntable 42 so as to be movable in the horizontal direction. These shutter members 53 are used to seal each through hole formed in the turntable 42 into which the work arms 48A and 48B were inserted when the work arms 48A and 48B were removed from the turntable 42. Is done.

  In the boiling water nuclear power plant 1, as described above, the nuclear fuel material in the fuel rods of the fuel assembly 8 loaded on the core 7 is melted, and the generated fuel debris 35 is placed on the lower mirror 5 of the reactor pressure vessel 3. Assuming that it is falling. The fuel debris retrieval method of the present embodiment using the fuel debris retrieval device 40 will be described in detail below with reference to FIGS. In the fuel debris retrieval method in the present embodiment, the fuel debris 35 falling on the lower mirror portion 5 of the reactor pressure vessel 3 is retrieved using the fuel debris retrieval device 40.

  Before starting the operation of taking out the fuel debris 35, the work house 29 is installed on the operation floor 23 of the reactor building 22 so as to cover the reactor well 24 (see FIG. 1). The overhead crane 32 is installed on a traveling rail provided near the ceiling of the work house 29 in the work house 29. The overhead crane 32 has a traveling carriage 33 that moves along the traveling rail and two transverse carriages 34 that are movably installed on the traveling carriage 33. A hook (not shown) is suspended from each traversing carriage 34. A shutter 30 that opens and closes is installed on one side surface of the work house 29 (for example, the side surface on the equipment temporary storage pool 25 side).

Using the overhead crane 32 in the work house 29, the shield plug 28 covering the reactor well 24, the head 18 of the reactor containment vessel 17, the upper lid 4 of the reactor pressure vessel 3, and the reactor pressure vessel 3 are used. the steam dryer 12 and steam-water separator 11 that the installed, for example, by the method described in JP 2013-19875, sequentially removed and carried to the outside through the space 31 of the working House 2 9.

  Thereafter, the fuel debris retrieval device 40 is suspended in the reactor pressure vessel 3 using the overhead crane 32. The suspension operation of the fuel debris retrieval device 40 will be described.

  The fuel debris retrieval device 40 and the lifting device 59 are loaded into the space 31 in the work house 29 with the shutter 30 opened, and placed on the operation floor 23 in the work house 29.

The lifting device 59 includes a base portion 60 and rotating drums 61 and 62. The rotating drums 61 and 62 are installed on the base portion 60. In FIG. 2, only two rotary drums, that is, the rotary drums 61 and 62 are illustrated, but actually three base drums are provided in the base portion 60. Wires 63 and 64 wound around the rotary drums 61 and 62 are attached to the ring member 43 of the fuel debris retrieval device 40. A wire (not shown) wound around another rotating drum (not shown) (not shown) is also attached to the ring member 43. The attachment positions of the three wires such as the wires 63 and 64 to the ring member 43 are arranged at equal intervals in the circumferential direction of the ring member 43. As a result, the fuel debris retrieval device 40 is held on the lifting device 59 by three wires.

  With the fuel debris retrieval device 40 attached to each wire wound around three rotary drums such as the rotary drums 61 and 62 of the lifting device 59, the lifting device 59 is suspended by the overhead crane 32 in the work house 29. The base portion 60 of the elevating device 59 is lowered to the position of the upper surface of the stepped portion 27 existing at the lowest position among the stepped portions formed on the inner surface of the reactor well 24 and supporting the shield plug 28. The base portion 60 of the lifting device 59 is held by the step portion 27. At this time, the fuel debris retrieval device 40 is held by the lifting device 59 by three wires such as wires 63 and 64 and is present in the reactor well 24 above the reactor pressure vessel 3. The three rotating drums such as the rotating drums 61 and 62 are rotated to rewind three wires such as the wires 63 and 64 wound around the rotating drums. By rewinding these wires, the fuel debris retrieval device 40 gradually descends in the reactor well 24, and eventually the ring-shaped fixing member 57 of the fuel debris retrieval device 40 is attached to the upper end of the reactor pressure vessel 3. It is lowered to the position of the upper surface of the existing flange. The fixing member 57 is fixed to the flange of the reactor pressure vessel 3 with a plurality of bolts in a state where the seal member 58 is disposed between the fixing member 57 and the flange of the reactor pressure vessel 3.

  At this time, the fuel debris retrieval device 40 is located in the reactor pressure vessel 3. Three wires such as the wires 63 and 64 attached to the ring member 43 are present inside the cylindrical expansion / contraction seal member 44 of the fuel debris retrieval device 40. By rotating three rotating drums such as the rotating drums 61 and 62 and rewinding the three wires such as the wires 63 and 64 wound around the rotating drums, the fuel debris retrieval device 40 is moved to the reactor pressure vessel 3. Further down. When the lower end portion of the storage container holding member 54 of the fuel debris retrieval device 40 is lowered to the vicinity of the upper lattice plate 10 in the reactor pressure vessel 3, the driving of the rotary drums 61, 62, etc. is stopped (see FIG. 2).

  Thereafter, hydraulic pressure (for example, water pressure) is applied to each cylinder 46 of the eight clamp devices 45 provided on the base portion 41 to move the piston in each cylinder 46 toward the inner surface of the reactor pressure vessel 3. . As a result, the piston rod 47 is pushed out of the cylinder 46, and the pressing portion attached to the tip of the piston rod 47 is pressed against the inner surface of the reactor pressure vessel 3. The base portion 41 is also held on the inner surface of the reactor pressure vessel 3 by each clamp device 45, and the turning table 42 is held by the base portion 41.

  One work arm driving device 49 for operating the work arm 48B is driven, and the gripping tool 37 of the work arm 48B grips the upper lattice plate 10. The other work arm driving device 49 for operating the work arm 48A is driven, and the cutting tool 36 of the work arm 48A cuts the portion of the upper lattice plate 10 gripped by the gripping tool 37. The movements of the work arms 48A and 48B are photographed by a monitoring camera (not shown) provided on the lower surface of the swivel table 42 and displayed on a display device (not shown) placed outside the reactor building 22. . The operator can monitor the movement of the work arms 48A and 48B and the cutting work outside the work house 29 by viewing the video displayed on the display device. In addition, the operator operates an operation panel (not shown) while watching the video displayed on the display device to control the respective work arm drive devices 49 of the work arms 48A and 48B, and the work arms 48A and 48B are disconnected. The cutting operation of the upper lattice plate 10 using the tool 36 and the gripping tool 37 is performed smoothly.

  After the periphery of the portion of the upper grid plate 10 gripped by the gripping tool 37 is cut by the cutting tool 36, the work arm drive device 49 is controlled to bend the work arm 48B, and the cut piece of the upper grid plate 10 is gripped. The gripping tool 37 is moved through the opening on the side wall of the storage container holding member 54 and directly above the storage container 55 placed on the bottom plate in the storage container holding member 54 (see FIG. 2). By opening the gripping tool 37, the cut piece of the upper lattice plate 10 falls into the storage container 55 and is stored in the storage container 55. The upper lattice plate 10 is cut using the work arms 48A and 48B, the cutting tool 36 and the gripping tool 37 and the upper lattice plate 10 is cut until a predetermined amount of the cut pieces of the upper lattice plate 10 are stored in the storage container 55. The operation of moving the piece into the storage container 55 is continuously performed. The fact that a predetermined amount of the cut pieces of the upper lattice plate 10 has been stored in the storage container 55 means that an image taken by another monitoring camera installed on the side wall of the storage container holding member 54 is placed outside the reactor building 22. This can be known by displaying on another display device (not shown).

  When a predetermined amount of cut pieces of the upper lattice plate 10 are stored in the storage container 55, the gripper 37 is moved to the outside of the storage container holding member 54, and the storage container 55 in the storage container holding member 54 is moved to the hoist 66. Driven and lifted from inside the storage container holding member 54 to the inside of the carry-out container 56 (see FIG. 3). After the storage container 55 reaches the inside of the carry-out container 56, the shutter member 53 is moved in the horizontal direction, and the passage in the storage container holding member 54 is blocked by the shutter member 53 (see FIG. 4). The closed shutter member 53 prevents the space in the carry-out container 56 from communicating with the space below the turntable 42.

  The carry-out container 56 storing the storage container 55 suspended from the hoist 66 is removed from the turning table 42 and lifted up to the space 31 in the work house 29 by the overhead crane 32 in the work house 29 (see FIG. 5). ). The carry-out container 56 is suspended by a wire 67 attached to the overhead crane 32. The carry-out container 56 lifted in the space 31 of the work house 29 is pulled up above the operation floor 23 by the overhead crane 32 and is suspended and held by the overhead crane 32. The hoist 66 in the carry-out container 56 is driven, and the storage container 55 in which the cut pieces of the upper lattice plate 10 are stored in the carry-out container 56 is lowered onto the operation floor 23 and placed on the operation floor 23. The storage container 55 is removed from the hoist 66, sealed with a lid, and transferred to a predetermined storage location outside the work house 29.

  The carry-out container 56 is hung by the overhead crane 32 and lowered to the upper surface of the swivel table 42 with the empty storage container 55 suspended from the internal hoist 66 so as to cover the passage in the storage container holding member 54. Thus, it is detachably attached to the upper surface of the turntable 42. The shutter member 53 is moved in the horizontal direction so that the passage in the storage container holding member 54 communicates with the space in the carry-out container 56. The hoist 66 is driven to lower the empty storage container 55, and the storage container 55 is placed on the bottom plate portion of the storage container holding member 54.

  Thereafter, as described above, the working container 48A, 48B, the cutting tool 36, and the gripping tool 37 are used to cut the upper lattice plate 10 and the storage container in the storage container holding member 54 of the cut piece of the upper lattice plate 10. Then, the upper grid plate 10 is removed. The storage container 55 that stores the cut pieces of the upper lattice plate 10 is transferred from the storage container holding member 54 to a predetermined storage location as described above. After the removal of the upper lattice plate 10 is completed, the core shroud 6 is similarly cut, and the storage container 55 storing the cut pieces of the core shroud 6 is also transferred to a predetermined storage location.

  When the core shroud 6 is cut and the core shroud 6 cannot be cut by the cutting tool 36 of the work arm 48A, hydraulic pressure is applied to the cylinders 46 of the clamp device 45 so that the pistons in the cylinders 46 are atomized. The reactor is moved toward the center of the reactor pressure vessel 3, and the pressing portion attached to the tip of the piston rod 47 is separated from the inner surface of the reactor pressure vessel 3. Each rotary drum such as the rotary drum 61 of the lifting device 59 is driven to rewind the wire from each rotary drum, and the base portion 41 of the fuel debris retrieval device 40 is lowered in the reactor pressure vessel 3. As the base portion 41 is lowered, the turning table 42 is also lowered. Since the fixing member 57 is fixed to the flange of the reactor pressure vessel 3, when the base portion 41 is lowered, the bellows-like cylindrical expansion / contraction seal member 44 is extended in the axial direction of the reactor pressure vessel 3. After the telescopic seal member 44 is lowered to some extent, the rotation of each rotating drum is stopped to stop the rewinding of the wire. For this reason, the descent of the base portion 41 stops. Thereafter, hydraulic pressure is applied to the cylinders 46 of the eight clamping devices 45 provided on the base 41 to move the pistons in the cylinders 46 toward the inner surface of the reactor pressure vessel 3. As a result, the pressing portion attached to the tip of the piston rod 47 is pressed against the inner surface of the reactor pressure vessel 3, and the base portion 41 is also held on the inner surface of the reactor pressure vessel 3 by each clamping device 45.

  Using the working arms 48A, 48B, the cutting tool 36 and the gripping tool 37, the core shroud 6 is cut and the cut pieces of the core shroud 6 are transferred into the storage container 55 held by the storage container holding member 54. Do. Further, the core support plate 9 and the control rod guide tube 13 are also cut and removed in the same manner using the work arms 48A and 48B, the cutting tool 36, and the gripping tool 37. If necessary in the cutting and removal, as described above, each rotating drum is rotated and the base portion 41 is lowered.

Fuel debris 35 is present on the inner surface of the lower mirror section 5 in the reactor pressure vessel 3. After these reactor internals in the reactor pressure vessel 3 are removed, each rotary drum of the lifting device 59 is driven so that the lower surface of the storage vessel holding member 54 is positioned near the surface of the fuel debris 35. The base part 41 is lowered (see FIG. 6). Then, the base portion 41 is held in the reactor pressure vessel 3 using each clamp device 45.

The cutting tool 36 of the working arm 48A first cuts the surface portion of the fuel debris 35. The gripping tool 37 of the working arm 48B grips the cut piece of the fuel debris 35. The cut pieces of the fuel debris 35 are transferred into the storage container 55 held by the storage container holding member 54 by operating the work arm 48B. In this way, the cutting of the fuel debris 35 existing on the inner surface of the lower mirror portion 5 by the cutting tool 36 of the work arm 48A is continuously performed, and the cut piece of the fuel debris 35 is stored by the gripping tool 37 of the work arm 48B. It is transferred into the storage container 55 held by the container holding member 54. As shown in FIGS. 3, 4 and 5, the storage container 55 in which the cut pieces of the fuel debris 35 are stored is transferred from the storage container holding member 54 into the work house 29 and further to a predetermined storage location. Be transported. Eventually, all the fuel debris 35 existing on the inner surface of the lower mirror part 5 is cut and removed.

  In the present embodiment, since the lower end portion of the elastic seal member 44 having the fixing member 57 attached to the upper end portion is attached to the upper surface of the base portion 41, the fixing member 57 is provided on the upper end portion of the reactor pressure vessel 3. When the base part 41 of the fuel debris retrieval device 40 is disposed in the reactor pressure vessel 3 below the upper end of the reactor pressure vessel 3, the expansion seal member 44 is attached to the upper surface of the flange. The space between the furnace pressure vessel 3 and the base portion 41 is sealed. Therefore, in the space below the base portion 41 in the reactor pressure vessel 3, when cutting the internal structure such as the upper lattice plate 10 and the core shroud 6 by the cutting tool 36 and cutting the fuel debris 35. The radioactive dust generated in the reactor reaches the space above the operation floor 23, for example, the space 31 in the work house 29, through an annular gap formed between the inner surface of the reactor pressure vessel 3 and the outer surface of the base portion 41. This can be prevented. Without being affected by the state of the inner surface of the reactor pressure vessel 3, the expandable seal member 44 can reliably eliminate the radioactive duct that passes between the reactor pressure vessel 3 and the base portion 41 and reaches the upper part of the operation floor 23.

  The cutting point of the object to be cut (internal reactor structure, fuel debris 35, etc.) by the cutting tool 36 of the work arm 48A comes to be positioned further downward, and the base portion 41 is lowered in the reactor pressure vessel 3. However, the expansion / contraction seal member 44 is only extended in the axial direction of the reactor pressure vessel 3, and the sealing performance of the radioactive dust by the expansion / contraction seal member 44 is not impaired.

Since the fixing member 57 for holding the upper end portion of the elastic seal member 44 is attached to a flange provided at the upper portion of the reactor pressure vessel 3, the fixing of the reactor pressure vessel 3 at the upper end of the elastic seal member 44 It can be done easily. A plurality of screw holes for bolts for attaching the upper lid 4 to the flange are formed in the flange of the reactor pressure vessel 3, and a plurality of bolts for fixing the fixing member 57 are engaged with these screw holes to fix the fixing member. 57 can be easily attached to the reactor pressure vessel 3.

  The fuel debris retrieval device 40 includes seal members 51A and 51B, and further, seal members are disposed between the working arms 48A and 48B and the turning table 42. Of the radioactive dust generated by the cutting work by the cutting tool 36 of the work arm 48A, the amount of radioactive dust reaching the space above the operation floor 23 can be remarkably suppressed.

  Since the work arms 48A and 48B are attached to the swivel table 42 that can swivel, the cutting work at different positions in the radial direction and the circumferential direction of the reactor pressure vessel 3 in the reactor pressure vessel 3 can be easily performed. Can do.

  In this embodiment, the storage container holding member 54 having an opening on the side wall and a bottom plate at the lower end is attached to the turntable 42 and disposed below the turntable 42, so that the storage container 55 is stored. It can be placed in the container holding member 54 and placed on the bottom plate portion, and the cut piece of the cutting object cut by the cutting tool 36 of the work arm 48A can be easily stored using the work arm 48B. 55 can be stored.

Passage in the container holding member 54, i.e., the presence of the transportable output container 56 covers formed in the container holding member 54 space, so attached to the upper surface of the turntable 42, beneath the turntable 42 by the cutter 36 When cutting the object to be cut, radioactive dust generated by the cutting reaches the upper part of the swivel table 42 through the space formed in the storage container holding member 54, and further enters the space above the operation floor 23. Reaching can be prevented. When transportable out container 56 covers the space in the mounted by the container holding member 54 to the turntable 42, transportable exits the container 56 serves as a seal member of the space in the accommodating container holding member 54.

For transportable out vessel 56 which is also used as a transport container of the storage container 55 to the cut pieces were accommodated in the cut object, through to the operation floor 23 that the container 55 within the reactor pressure vessel 3 and reactor well within 24 It can be easily transferred. Elevating mechanism container 55 accommodating the cut pieces of the workpiece to be cut is placed on transportable out container 56 (e.g., hoist 66) it is possible to house the hung on transportable out vessel 56, transportable out vessel The storage container 55 can be easily transferred onto the operation floor 23 by lifting 56 with the overhead crane 32 in the work house 29. By lowering by a transportable exits vessel 56 empty container 55 in a state of suspended to the hoist 66 overhead crane 32, placing the empty container 55, on the bottom plate in the container holding member 54 Can be easily done.

Since the transportable out vessel 56 inside in the receiving container 55 removably attached to the upper surface of the turn table 42 is suspended to the hoist 66 installed in the container 56 out transportable, the bottom plate in the container holding member 54 the in which container 55 is filled with cut pieces of cutting the object is placed on top of, can be easily pulled transportable out container 5 6 by driving the hoist 66, also transportable out vessel 5 6 The empty storage container 55 can be easily lowered onto the bottom plate portion in the storage container holding member 54 by driving the hoist 66. The container 55 is suspended to the hoist 66 installed in the container 56 out transportable is between the bottom plate portion of the operation floor 23 container holding member 54, realizes easy transport of the container 55 One factor.

The container 55 accommodating the cut pieces of the workpiece to be cut after the step of transferring the hoist 66 from the storage container holding member 54 to the transportable out vessel 56, is transportable out vessel 56 to raise transportable exits vessel 56 from the turntable 42 before being removed, the shutter member 53 is inserted into the container holding member 54 from the opening of the side wall of the container holding member 54, to block the passage in the housing container holding member 54 which communicates with the transportable out vessel 56 . Therefore, transportable out container 56 cut pieces container 55 accommodating the are placed inside the cutting object, when pulled is detached from the turntable 42, the reactor pressure vessel 3 at a lower than turntable 42 The radioactive dust existing inside is prevented from reaching upward through the passage in the storage container holding member 54 by the shutter member 53 that blocks the passage in the storage container holding member 54.

  A fuel debris retrieval method according to embodiment 2, which is another preferred embodiment of the present invention, will be described with reference to FIG.

  In the fuel debris retrieval method of the present embodiment, the fuel debris retrieval device 40 and the radiation shield 68 used in the fuel debris retrieval method of the first embodiment are used. The radiation shielding body 68 is a radiation shielding body in which water 69 is filled in a bag.

In the fuel debris retrieval method of this embodiment, the base portion 60 of the lifting device 59 is installed on the stepped portion 27 formed on the side wall of the reactor well 24 as in the first embodiment. The ring member 43 of the fuel debris retrieval device 40 is attached to three wires such as the wires 63 and 64 wound around the three rotating drums such as the rotating drums 61 and 62 attached to the base portion 60, and the fuel debris is removed. base unit 41 and the turning table 4 2 of the take-out device 40 is arranged in the reactor pressure vessel 3. The fixing member 57 is attached to the upper surface of the flange at the upper end portion of the reactor pressure vessel 3, and the lower end portion of the expansion / contraction seal member 44 having the upper end portion attached to the fixing member 57 is attached to the ring member 43. Turning table 4 2 attached working arms 48A, 48B, by using the cutting tool 36 and gripper 37, in the same manner as in Example 1, a reactor pressure vessel 3 the top guide 10 and the like core shroud 6 The in-furnace structure is cut and removed. FIG. 7 shows a state in which such a reactor internal structure is removed and the base portion 41 is lowered to the vicinity of the fuel debris 35 existing on the inner surface of the lower mirror portion 5 in the reactor pressure vessel 3. The pressing member of each clamp device 45 attached to the base portion 41 is in contact with the inner surface of the reactor pressure vessel 3, and the base portion 41 is held on the inner surface of the reactor pressure vessel 3 by each clamp device 45.

  In the present embodiment, the radiation shielding body 68 is disposed inside the expandable seal member 44 in the reactor pressure vessel 3 with the bag filled with water 69. The radiation shielding body 68 is suspended from two traversing carts 34 of the overhead crane 32 in the work house 29 by wires 71 and 72. The radiation shielding body 68 is located immediately above the base portion 41 and the turntable 42. The bag of the radiation shielding body 68 is made of a material obtained by integrating an aramid fiber and a polyurethane sheet with an aramid fiber sandwiched between polyurethane sheets, like the stretchable sealing member 44.

  The supply of water 69 into the bag of the radiation shield 68 will be described. The upper surface of the bag is attached to the two wires 71 and 72 attached to the hooks of the two traversing carts 34, and the empty bag is attached to the reactor pressure inside the elastic seal member 44 by the two traversing carts 34. The container 3 is lowered to the position of the upper end portion (position shown in FIG. 7). When reaching a predetermined position, the descent of the bag is stopped, and a water supply pump (not shown) installed on the operation floor 23 is driven to supply water 69 into the bag through the water supply hose 70. The supply of water 69 causes the bag to expand, and the side surface of the bag comes into contact with the inner surface of the stretchable seal member 44 (see FIG. 7). At this time, the supply of water 69 into the bag is stopped. The bag filled with water functions as a radiation shield 68.

  Three wires, such as wires 63 and 64, which are wound around three rotary drums such as the rotary drums 61 and 62 attached to the base portion 60 and attached to the ring member 43, cause the radiation shield 68 to move in the vertical direction. It penetrates. In order to prevent leakage of the water 69 in the bag of the radiation shielding body 68 to the outside and to facilitate the movement of the three wires when the base portion 41 is moved in the vertical direction, the radiation shielding body 68 3 First hollow tubes (not shown) extending in the axial direction of the reactor pressure vessel 3 are disposed inside the bag at three locations through which the wires pass, and both ends of each first hollow tube are on the upper surface of the bag. And attached to the lower surface while maintaining airtightness. Both ends of each first hollow tube are open to the outside of the bag. Each of the three wires passes separately through each such first hollow tube.

Also in this embodiment, in the same manner as in Example 1, the transportable exit container 56 hung container 55 filled with cut pieces of object to be cut inside the hoist 66, it is necessary to lift up the working House 29. Therefore, the thick second hollow tube having an inner diameter of transportable out container 56 can pass is, similarly to the first hollow tube, is arranged in the bag, both ends maintain the airtightness in the upper and lower surfaces of the bag It is attached as follows. By placing the second hollow tube into the bag of the radiation shield 68, transportable and exits vessel 56 accommodating therein the container 55 by another overhead crane that is installed in the working house 29, working House 29 The water 69 in the radiation shield 68 can be prevented from leaking.

Using the work arm 48A having the cutting tool 36, the work arm 48B having the gripping tool 37, and the like, the cutting object such as the in-furnace structure is cut and the cut piece is put into the storage container 55, as in the first embodiment. storage, and transport of transportable out container 56 accommodating the storage container 55 is made of. In particular, in the state shown in FIG. 7, the fuel debris 35 is cut by using the work arm 48 </ b> A having the cutting tool 36 and the work arm 48 </ b> B having the gripping tool 37 provided on the turning table 42. The cut pieces are stored in a storage container 55 disposed in the storage container holding member 54. In this way, the fuel debris 35 in the reactor pressure vessel 3 is removed.

In the present embodiment, each effect produced in the first embodiment can be obtained. Furthermore, in this embodiment, the radiation shield 68 filled with water 69 is disposed above the base portion 41 and the turntable 42 in the reactor pressure vessel 3, so that the base portion 41 and the turntable 42 are moved upward from below. The incoming radiation can be shielded by the radiation shield 68. For this reason, the exposure of the worker who is on the operation floor 23 can be reduced. Incidentally, the radiation shield 68, there is a possibility that in the second hollow tube is provided for forming a passageway transportable out container 56 moves through the second hollow tube radiation was filled with water 69 By installing the radiation shielding body 68, the amount of radiation reaching the operation floor 23 can be significantly reduced.

  In addition, since the radiation shielding body 68 filled with water 69 is installed in the reactor pressure vessel 3, it is easy to install the radiation shielding body in the reactor pressure vessel 3.

  A fuel debris retrieval device according to embodiment 3, which is another preferred embodiment of the present invention, will be described with reference to FIG.

  The fuel debris retrieval device 40A according to the present embodiment has a configuration in which a radiation shield 74 is added to the fuel debris retrieval device 40 according to the first embodiment. The annular radiation shielding body 74 has a bag made of a material obtained by integrating an aramid fiber and a polyurethane sheet by sandwiching the aramid fiber between polyurethane sheets. The radiation shield 74 surrounds the cylindrical support portion 65 and is attached to the cylindrical support portion 65 and the base portion 41. A plurality of water supply hoses 75 are arranged inside the elastic seal member 44 and attached to the cylindrical support portion 65, and communicated with the inside of the bag of the radiation shield 74. The other configuration of the fuel debris retrieval device 40A is the same as that of the fuel debris retrieval device 40.

  In the fuel debris retrieval method using the fuel debris retrieval device 40 </ b> A of the present embodiment, the base portion 41 to which the annular bag of the radiation shield 74 is attached is inserted into the reactor pressure vessel 3. The base portion 60 of the lifting device 59 is installed on the step portion 27 formed on the side wall of the reactor well 24. Each wire wound around three rotating drums installed in the base portion 60 is attached to the ring member 43 of the fuel debris retrieval device 40A, and the base portion 41 is held by the lifting device 59. As a result, the turning table 42, the work arm 48 </ b> A having the cutting tool 36, and the work arm 48 </ b> B having the gripping tool 37 are also held by the lifting device 59. Further, the base portion 41 is held on the inner surface of the reactor pressure vessel 3 by each clamp device 45 as in the first embodiment. At this time, the fixing member 57 is attached to the upper surface of the flange at the upper end portion of the reactor pressure vessel 3, and the lower end portion of the elastic seal member 44 having the upper end portion attached to the fixing member 57 is attached to the ring member 43. Yes. The plurality of water supply hoses 75 are disposed inside the elastic seal member 44 and connected to a water supply pump (not shown) installed on the operation floor 23.

  When the base portion 41 is held by the elevating device 59 and held by the clamping device 45 on the inner surface of the reactor pressure vessel 3, the water supply pump is driven into the radiation shielding body 74 bag through each water supply hose 75. Supply water. This bag expands in a donut shape around the cylindrical support portion 65 by supplying water. For this reason, an annular radiation shielding body 74 filled with water is disposed in the annular space between the cylindrical support portion 65 and the reactor pressure vessel 3, and more than the base portion 41 and the swivel table 42 in the reactor pressure vessel 3. Radiation directed upward through the annular space between the base portion 41 and the reactor pressure vessel 3 from below is shielded by the radiation shield 74.

Using the work arm 48A having the cutting tool 36, the work arm 48B having the gripping tool 37, and the like, the cutting object such as the in-furnace structure is cut and the cut piece is put into the storage container 55, as in the first embodiment. storage, and transport of transportable out container 56 accommodating the storage container 55 is made of. In particular, in the state shown in FIG. 8, the fuel debris 35 is cut using the work arm 48 </ b> A having the cutting tool 36 and the work arm 48 </ b> B having the gripping tool 37 provided on the turning table 42. The cut pieces are stored in a storage container 55 disposed in the storage container holding member 54. In this way, the fuel debris 35 in the reactor pressure vessel 3 is removed.

  In the present embodiment, each effect produced in the first embodiment can be obtained. Further, in the present embodiment, the radiation shielding body 74 filled with water is arranged so as to cover the annular space formed between the base portion 41 and the reactor pressure vessel 3. Further, the radiation that is released from the radioactive material existing below and passes upward between the base portion 41 and the reactor pressure vessel 3 can be shielded by the radiation shield 74.

  A fuel debris retrieval device according to embodiment 4, which is another preferred embodiment of the present invention, will be described with reference to FIG.

  The fuel debris retrieval device 40B of the present embodiment has a configuration in which the base portion 41 and the turning table 42 are changed to the base portion 76 in the fuel debris retrieval device 40 described above. Substantially, the base portion 76 has a configuration in which the base portion 41 and the turntable 42 are integrated. The base portion 76 is made of a radiation shielding material. The working arm 48 </ b> A having the cutting tool 36 and the working arm 48 </ b> B having the gripping tool 37 are separately inserted into two through holes formed in the base part 76 and installed on the base part 76. The annular gaps between each of the work arms 48A and 48B and the base portion 76 are sealed with seal members (not shown). The lengths of the working arms 48A and 48B used in the present embodiment are the same as those of the working arms 48A and 48B used in the fuel debris retrieval device 40 because the fuel debris retrieval device 40B does not have the swivel table 42. It is longer than the length of. The other structure of the fuel debris retrieval device 40B is the same as that of the fuel debris retrieval device 40.

  In the fuel debris retrieval method using the fuel debris retrieval device 40B according to the present embodiment, the fuel debris retrieval device 40B is used. However, similarly to the fuel debris retrieval method using the fuel debris retrieval device 40 according to the first embodiment, cutting is performed. Using the work arm 48A having the tool 36 and the work arm 48B having the gripping tool 37, the cutting object such as the in-furnace structure is cut and the cut piece is stored in the storage container 55. In particular, in the state shown in FIG. 10, the fuel debris 35 is cut using the work arm 48 </ b> A having the cutting tool 36 and the work arm 48 </ b> B having the gripping tool 37 provided on the base portion 76. The cut pieces are stored in a storage container 55 disposed in the storage container holding member 54. In this way, the fuel debris 35 in the reactor pressure vessel 3 is removed.

  In the present embodiment, each effect produced in the first embodiment can be obtained. Furthermore, in this embodiment, since the turning table 42 and the seal members 51A and 51B are not required, the structure of the fuel debris retrieval device 40B can be simplified.

  A fuel debris retrieval device according to embodiment 5, which is another preferred embodiment of the present invention, will be described with reference to FIG.

The fuel debris retrieval device 40C according to the present embodiment has a configuration in which a blocking device 103 is provided instead of the shutter member 52 in the fuel debris retrieval device 40B according to the fourth embodiment. In the fuel debris retrieval device 40 </ b> C, the cylindrical portion 77 is installed at a position where each of the working arm 48 </ b> A having the cutting tool 36 and the working arm 48 </ b> B having the gripping tool 37 penetrates the base portion 76. Each cylinder 7 7 penetrates the base portion 76. A working arm 48 </ b> A having the cutting tool 36 is inserted into one cylindrical portion 77 and is detachably attached to the cylindrical portion 77. A work arm 48 </ b> B having a gripping tool 37 is inserted into another cylindrical portion 77 and is detachably attached to the cylindrical portion 77.

  The blocking device 103 is attached to the lower end surface of each cylindrical portion 77. The configuration of the blocking device 103 will be described with reference to FIGS. 13, 14, 15, and 16. The sealing device 103 shown in FIG. 14 has the sealing device 103 attached to the lower end surface of the cylindrical portion 77 in a state where the working arm 48B is pulled out from the cylindrical portion 77 and not inserted into the cylindrical portion 77 from below. The configuration when viewed is shown. The sealing device 103 has eight sealing plates 80 having an isosceles triangular shape, and each sealing plate 80 is attached to a rotating shaft 84 attached to a support member 83 attached to the lower end surface of the cylindrical portion 77. It is done. Each blocking plate 80 is formed of a radiation shielding body. A structure for attaching the sealing plate 80 to the lower end surface of the cylindrical portion 77 will be described with reference to FIGS. 15 and 16. The rotating shaft 84 is rotatably attached to a support member 83 attached to the lower end surface of the cylindrical portion 77 (see FIG. 15). A support member 83 is disposed in a notch 81 formed in the blocking plate 80. Both end portions of the rotating shaft 84 rotatably attached to the support member 83 are inserted into through holes formed in boss portions 82 formed on both sides of the notch portion 81 at the end portion of the sealing plate 80 ( (See FIG. 16). Both end portions of the rotation shaft 84 are fixed to boss portions 82 formed on both sides of the notch portion 81. For this reason, the rotating shaft 84 fixed to the blocking plate 80 rotates in the through-hole formed in the support member 83, and the blocking plate 80 also rotates. The other seven sealing plates 80 have the same configuration, and a rotation shaft 84 attached to the boss portion 82 of the sealing plate 80 is formed on each support member 83 attached to the lower end surface of the cylindrical portion 77. Rotate in the through hole.

  Eight hole portions 78 opened at the lower end surface of the cylindrical portion 77 are arranged at equal intervals in the circumferential direction of the cylindrical portion 77. A compression spring 85 is disposed in each hole 78. One end of the compression spring 85 is fixed to the bottom of the hole 78, and the other end of the compression spring 85 is attached to a surface of the sealing plate 80 that faces the lower end surface of the cylindrical portion 77. When the tip of the gripping tool 37 of the work arm 48B is positioned above the lower end of the cylindrical portion 77, the respective sealing springs 80 are pulled to the lower end surface side of the cylindrical portion 77 by the action of the compression springs 85. The through-hole into which the work arm 48B is inserted is blocked by eight blocking plates 80 (see FIG. 13).

  When the working arm 48B is inserted into the through-hole of the cylindrical portion 77 and the working arm 48B protrudes downward from the lower end surface of the cylindrical portion 77, each blocking plate 80 is pushed down by the gripping tool 37 of the working arm 48B. The work arm 48B can move downward from the lower end surface of the cylindrical portion 77 (see FIG. 12).

  A cylindrical portion 77 for the working arm 48A having the cutting tool 36 and having the sealing device 103 attached to the lower end surface is also a cylindrical portion 77 for the working arm 48B having the cutting tool 36 and having the sealing device 103 attached to the lower end surface. In the same manner, the base portion 76 is attached to the base portion 76 through the base portion 76.

  In the fuel debris retrieval method using the fuel debris retrieval device 40C according to the present embodiment, the fuel debris retrieval device 40C is used. However, similarly to the fuel debris retrieval method using the fuel debris retrieval device 40B according to the fourth embodiment, cutting is performed. Using the work arm 48A having the tool 36 and the work arm 48B having the gripping tool 37, cutting of the object to be cut such as the in-furnace structure and the fuel debris 35, and the storing of the cut pieces in the storage container 55 can be performed. Done.

  In the present embodiment, each effect produced in the fourth embodiment can be obtained.

  In the fuel debris retrieval devices 40, 40 </ b> A and 40 </ b> B described above, the shutter member 52 may be removed, and the cylindrical portion 77 and the sealing device 103 provided in the fuel debris retrieval device 40 </ b> C may be attached to the turning table 42 instead of the shutter member 52. Good. The pair of cylindrical portions 77 having the sealing device 103 attached to the lower end surface penetrate the turning table 42 in the vertical direction and are attached to the turning table 42. The working arm 48 </ b> A is inserted into one cylindrical part 77, and the working arm 48 </ b> B is inserted into another cylindrical part 77.

  A fuel debris retrieval device according to embodiment 6, which is another preferred embodiment of the present invention, will be described with reference to FIG.

  The fuel debris retrieval device 40D of the present embodiment has a configuration in which a cylindrical seal device 86 is provided instead of the expandable seal member 44 in the fuel debris retrieval device 40B of the fourth embodiment. The cylindrical seal device 86 includes a plurality of cylindrical seal members 87, a seal lifting device 93, and a lifting device turning mechanism 98. The other structure of the fuel debris retrieval device 40D is the same as that of the fuel debris retrieval device 40B.

  A detailed configuration of the cylindrical seal member 87 will be described with reference to FIG. The cylindrical seal member 87 includes a cylindrical portion 88, an upper flange 89, a lower flange 90, a ring member 91, and a ring-shaped seal member 104. The upper flange 89 is attached to the upper end of the cylindrical portion 88 by welding, and the lower flange 90 is attached to the lower end of the cylindrical portion 88 by welding. The ring member 91 is attached to the cylindrical portion 88 by welding between the upper flange 89 and the lower flange. The ring member 91 is disposed near the upper flange 89. The upper flange 89 is formed with an annular groove that is open over the front surface of the side surface, and a ring-shaped seal member 104 is mounted in the groove.

Specifically, the cylindrical portion 88 includes a first cylindrical portion 88A and a second cylindrical portion 88B. The axial length of the first cylindrical portion 88A is shorter than the axial length of the second cylindrical portion 88B. More specifically, the upper flange 89, the lower flange 90, and the ring member 91 are joined to the cylindrical portion 88. The upper flange 89 is at the upper end of the first cylindrical portion 88A, and the ring member 91 is at the lower end of the first cylindrical portion 88A. The upper end of the second cylindrical portion 88B and the lower flange 90 are respectively attached to the lower end of the second cylindrical portion 88B by welding. The cylindrical portions 88, 88A and 88B, the upper flange 89, the lower flange 90, and the ring member 91 are made of metal (for example, made of stainless steel or carbon steel).

  The cylindrical seal member 87 located at the lowest position in the cylindrical seal device 86 is attached to the upper surface of the base portion 76. The lower end of the cylindrical portion 88 of the cylindrical seal member 87, that is, the lower end of the second cylindrical portion 88B is attached to the upper surface of the base portion 76 by welding. As described above, the seal member 104 is attached to the upper flange 89 of the cylindrical seal member 87.

The seal lifting device 93 includes a cylinder 94, a piston 95, a piston rod 96 and a holding member 97. A gear (not shown) is attached to the outer surface of the lower end portion of the cylinder 94 so as to surround the cylinder 94. Eight seal elevating devices 93 are arranged at equal intervals in the circumferential direction of the ring-shaped fixing member 57 and are rotatably installed on the support member 101 attached to the upper surface of the fixing member 57. A cylinder 94 is installed on the support member 101, and a piston 95 is disposed in the cylinder 94 . A piston rod 96 attached to the lower surface of the piston 95 extends downward and penetrates the support member 101 and the fixing member 57. The holding member 97 is disposed below the lower surface of the fixing member 57 and is attached to the lower end of the piston rod 96.

  The lifting / lowering device turning mechanism 98 is disposed corresponding to each seal lifting / lowering device 93 and includes a motor 99 and a speed reduction device 100. Each of the motor 99 and the speed reducer 100 is installed on the upper surface of the support member 101. The rotation shaft of the motor 99 is connected to the reduction gear 100. The final stage gear of the reduction gear 100 meshes with the above-described gear that surrounds the outer surface of the cylinder 94.

  A metal cylindrical outer cylinder portion 102 disposed inside the eight seal elevating devices 93 is attached to the base portion 76. The outer cylinder portion 102 is machined including the inner surface.

  The fuel debris retrieval method of the present embodiment using the fuel debris retrieval device 40D will be described below. As in the first embodiment, the shield plug 28, the head 18, the upper lid 4, the steam dryer 12, and the steam / water separator 11 are removed.

In the work house 29, the lifting device 59 is operated while the fixing member 57 of the fuel debris retrieval device 40D is attached to each wire wound around three rotating drums such as the rotating drums 61 and 62 of the lifting device 59. Suspended by the overhead crane 32 in the house 29, the base portion 60 of the lifting device 59 is lowered to the position of the upper surface of the step portion 27 formed on the side wall of the reactor well 24 and placed on the step portion 27. . One cylindrical seal member 87 attached to the base portion 76 of the fuel debris retrieval device 40 </ b> D is held by four seal lifting devices 93 among the eight seal lifting devices 93 provided on the base portion 76 . One each is arranged between the four seal lifting devices 93. The four seal lifting devices 93 having the holding members 97 holding the cylindrical seal members 87 are referred to as a first group of seal lifting devices 93 for convenience. The remaining seal elevating device 93 does not hold the cylindrical seal member 87. The remaining four seal lifting devices 93 are referred to as a second group of seal lifting devices 93 for convenience.

  The holding of the one cylindrical seal member 87 by the four seal lifting devices 93 of the first group will be described. Respective holding members 97 provided at the lower ends of the piston rods 96 of the four seal lifting devices 93 in the first group are arranged toward the center of the cylindrical seal member 87. When the lower surface of the ring member 91 of the cylindrical seal member 87 is placed on these holding members 97, the cylindrical seal member 87 is held by these holding members 97. As a result, the base portion 76 of the fuel debris retrieval device 40D, to which the storage container holding member 54, the carry-out container 56, and the work arms 48A and 48B are attached, is held by the fixing member 57 by the seal elevating device 93.

  The three rotating drums of the lifting device 59 placed on the stepped portion 27 are rotated to rewind three wires (for example, the wire 63) wound around these rotating drums, and the fixing member 57 And the base part 76 is lowered. Eventually, the fixing member 57 and the base portion 76 are inserted into the reactor pressure vessel 3, and the fixing member 57 is seated on the upper surface of the flange of the reactor pressure vessel 3. The fixing member 57 is detachably fixed to the flange of the reactor pressure vessel 3 by a plurality of bolts. Thereafter, the other plurality of cylindrical seal members 87 are coupled onto the cylindrical seal member 87 held by the holding member 97 until the base portion 76 is lowered to a predetermined position in the reactor pressure vessel 3.

  The other cylindrical seal member 87 to be coupled is suspended by another overhead crane installed in the work house 29 and lowered onto the cylindrical seal member 87 held by the holding member 97. When the lower surface of the lower flange 90 of the former cylindrical seal member 87 contacts the upper surface of the upper flange 89 of the latter cylindrical seal member 87, a plurality of bolts 92 attached to the lower flange 90 of the former cylindrical seal member 87 are removed. In use, the lower flange 90 of the former cylindrical seal member 87 is attached to the upper flange 89 of the latter cylindrical seal member 87. As a result, the cylindrical seal members 87 are connected (see “the state at the time of connection” on the right side of FIG. 19). These cylindrical seal members 87 are disposed inside the outer cylinder portion 102.

The latter cylindrical sealing member 87 of the ring member 91 while decreasing the fluid pressure in the lower region than the piston 9 5 of each cylinder 94 to have four sealing lifting device of the first group 93 holds the cylinder 94 of the piston 9 5 than adding the liquid pressure in the upper region. And each of the pistons 9 5 descent of the sealing lifting device 93, the piston 9 5 to the piston rod 96 the support members 97 which are connected in is lowered (see "status under Futoki" on the left side of FIG. 19). When their piston 9 5 has been lowered to the lowest position, to stop the supply of hydraulic pressure to the cylinder 94 of each seal lifting apparatus 93 of the first group. At this time, the piston 95 by supplying hydraulic pressure to the lower region than the piston 9 5 of each cylinder 94 of the four sealing lifting device 93 of the second group, the four sealing lifting device of the second group 93 The upper surface of each holding member 97 is raised until it contacts the lower surface of the ring member 91 of the former cylindrical seal member 87. When each holding member 97 comes into contact with the lower surface of the ring member 91 , supply of hydraulic pressure to the cylinders 94 of the four seal lifting devices 93 in the second group is stopped.

Then, the motor 99 of the raising / lowering device turning mechanism 98 provided corresponding to the four seal raising / lowering devices 93 of the first group is driven. The rotational speed of the motor 99 is decelerated by the reduction gear 100 and then transmitted to the cylinder 94 by a gear, and the cylinder 94 rotates by 90 °. As a result, each of the holding members 97 of the four seal lifting devices 93 of the first group facing the center of the cylindrical seal member 87 is rotated by 90 °, and these holding members 97 are rotated by the latter cylindrical seal member 87. The ring member 91 is not held. By ring member 91 of the cylindrical sealing member 87 located above is held by each holding member 9 7 four sealing lifting device 93 of the second group, the base portion 76 and two cylindrical sealing member 87, the It is held by two groups of four seal lifting devices 93.

  The above operation is repeated until the base portion 76 is lowered to a predetermined position in the reactor pressure vessel 3, and the cylindrical seal members 87 are sequentially connected. When the base portion 76 is lowered to a predetermined position in the reactor pressure vessel 3, the working arm 48A having the cutting tool 36 and the working arm 48B having the gripping tool 37 provided on the base portion 76 are used. 4, the in-core structure such as the upper grid plate 10 and the core shroud 6 in the reactor pressure vessel 3 and the fuel debris 35 are cut, and these cut pieces are stored in the storage container 55. Thereafter, the carry-out container 56 containing the storage container 55 filled with the cut pieces is lifted up to the work house 29 and transferred to a predetermined storage location. When the base portion 76 is lowered to a predetermined position, the base portion 76 is held on the inner surface of the reactor pressure vessel 3 by each clamp device 45 provided on the base portion 76. Thereby, the rolling of the base part 76 at the time of the cutting | disconnection of a cutting target object can be prevented. The outer surface of the seal member 104 attached to the upper flange 89 of the uppermost cylindrical seal member 87 is in contact with the inner surface of the outer cylinder portion 102, and the connected cylindrical seal member 87 and the reactor pressure vessel The radioactive dust which exists in the annular space between 3 reaches | attains above the operating floor 23, and is prevented.

  In the present embodiment, each effect produced in the fourth embodiment can be obtained. Since the inner surface of the outer cylinder portion 102 that has been machined contacts the seal member 104 attached to the upper flange 89, radioactive dust is generated in the operation floor more than when the seal member contacts the inner surface of the reactor pressure vessel 3. Reaching above 23 can be suppressed.

  The cylindrical seal device 86 in the present embodiment can be applied to the fuel debris retrieval devices 40 and 40A having the turning table 42.

DESCRIPTION OF SYMBOLS 1 ... Boiling water type nuclear power plant, 2 ... Reactor, 3 ... Reactor pressure vessel, 6 ... Core shroud, 7 ... Core, 17 ... Reactor containment vessel, 22 ... Reactor building, 23 ... Operation floor, 24 ... Atom Furnace well, 29 ... work house, 35 ... fuel debris, 36 ... cutting tool, 35 ... gripping tool, 40, 40A, 40B, 40C, 40D ... fuel debris removal device, 41, 60, 76 ... base part, 42 ... swivel Table, 43, 91 ... Ring member, 44 ... Telescopic seal member, 45 ... Clamp device, 48A, 48B ... Work arm, 49 ... Work arm drive device, 51A, 52A, 57, 58, 104 ... Seal member, 52, 53 ... Shutter member, 54 ... Storage container holding member, 55 ... Storage container, 56 ... Unloading container, 57 ... Fixing member, 59 ... Lifting device, 61, 62 ... Rotating drum, 65 ... Cylindrical support part, 6 8 , 74: Radiation shield, 70, 75 ... Water supply hose, 79 ... Cylindrical portion, 80 ... Sealing plate, 83 ... Supporting member, 84 ... Rotating shaft, 85 ... Compression spring, 86 ... Cylindrical seal device, 87 ... Cylindrical Seal member 88 ... Cylindrical part 89 ... Upper flange 90 ... Lower flange 93 ... Seal lifting device 98 ... Lifting device turning mechanism 103 ... Sealing device

Claims (14)

A base part, a first work arm having a cutting tool and a second work arm having a gripping tool provided on the base part, and a lower end part attached to the base part and disposed above the base part, and an upper end A cylindrical expansion and contraction sealing member with a fixing member attached to the part,
A storage container holding member for holding a storage container in which an opening into which the gripping tool of the second working arm is inserted is formed in a side wall below the base part and is disposed inside is attached to the base part. And a fuel debris retrieval device extending downward from the base portion.   An unloading container that covers the upper portion of the storage container holding member and forms a space for storing the storage container therein is disposed above the base portion, and the discharge container is detachably attached to the base portion. 2. The fuel debris retrieval device according to 1. A pivot table attached to the base portion so as to be pivotable; the first work arm and the second work arm are attached to the pivot table; and the storage container holding member is attached to the pivot table and extends downwardly of the swivel table, the housing and loading container covering above of the container holding member is disposed above the turntable, according to claim 1, wherein the discharge vessel is releasably attached to the turntable Fuel debris retrieval device. The fuel debris retrieval device according to claim 2 or 3 , wherein a storage container moving device for moving the storage container in the vertical direction is attached in the carry-out container. Shutter member for opening and closing the container passes paths of the container holding the member, according to any one of claims 1 is attached to the base portion to be movable in the horizontal direction 3 Fuel debris retrieval device.   A first cylindrical portion and a second cylindrical portion that are attached to the base portion through the base portion and have through holes formed therein, respectively, and the first working arm is formed in the through hole of the first cylindrical portion. A lower end surface of the first cylindrical portion having a plurality of rotatable first sealing plates that are opened when inserted and closed when the first working arm is pulled out from the through hole of the first cylindrical portion. A first closing device provided on the second cylindrical portion, and the second working arm is opened when the second working arm is inserted into the through hole of the second cylindrical portion, and the second working arm is pulled from the through hole of the second cylindrical portion. 2. The fuel debris retrieval device according to claim 1, further comprising a second sealing device provided on a lower end surface of the second cylindrical portion, the second sealing plate having a plurality of rotatable second sealing plates that are closed when pulled out. A first working arm having a cutting tool and a second working arm having a gripping tool provided on the base part; a cylindrical member attached to the base part and extending upward; and passing through the cylindrical member. A plurality of cylindrical seal members that are connected to each other in the axial direction of the reactor pressure vessel and disposed in the reactor pressure vessel; A first holding member that holds a first ring member provided on the cylindrical seal member located below the cylindrical seal member, and is disposed in a circumferential direction of the cylindrical member so as to surround the cylindrical member; A plurality of first seal elevating devices attached to a ring-shaped fixing member attached to the upper end of the reactor pressure vessel, and the other located above the two cylindrical seal members A second holding member for holding a second ring member provided on the cylindrical seal member; and a plurality of second mounting members attached to the fixing member, which surround the cylindrical member and are arranged in a circumferential direction of the cylindrical member. 2 seal lifting device,
A fuel debris retrieval device, wherein a lower end portion of the cylindrical seal member located at a lowermost position among the plurality of cylindrical seal members is attached to the base portion. A first elevating device turning mechanism for rotating the first seal elevating device within a predetermined angle range is attached to the fixing member for each of the first seal elevating devices, and rotates the second seal elevating device within a predetermined angle range. The fuel debris retrieval device according to claim 7 , wherein a second lifting device turning mechanism is attached to the fixing member for each second seal lifting device. A fuel debris retrieval method for retrieving fuel debris from a reactor pressure vessel using the fuel debris retrieval device according to claim 1,
The fixing member is detachably attached to the upper surface of the flange at the upper end of the reactor pressure vessel in a sealed state,
Lowering the base and placing it in the reactor pressure vessel;
Cutting the fuel debris present in the reactor pressure vessel using the cutting tool of the first working arm;
The fuel debris cut piece cut by the cutting tool is gripped by the gripping tool of the second working arm and stored in the storage container in the storage container holding member through the opening. Debris retrieval method. A carry-out container that covers the upper part of the storage container holding member and forms a space for storing the storage container therein is disposed above the base part, and the carry-out container is detachably attached to the base part. ,
The container in which the cut pieces are housed and transported from the container holding member in the space of the discharge vessel, the discharge vessel which accommodates the container to claim 9 taken out from the reactor pressure vessel The fuel debris retrieval method described. The storage container is transferred from the storage container holding member into the space of the carry-out container using a storage container transfer device provided in the carry-out container, and the reactor pressure vessel of the carry-out container removal from the extraction method of fuel debris of claim 1 0, wherein the container is performed in a state held by the container transfer device. After the container has been transferred to the unloading container from the container holding member, the passage which is connected to the carry-out containers of the container holding the member, according to claim 1 0, which is blocked by the shutter member To take out fuel debris. A fuel debris retrieval method for retrieving fuel debris from a reactor pressure vessel using the fuel debris retrieval device according to claim 7 ,
The fixing member is disposed on the upper surface of the flange at the upper end of the reactor pressure vessel, and in a sealed state, is removably attached to the flange.
The plurality of cylindrical seal members including the cylindrical seal member are sequentially connected to each other upward from the lowest cylindrical seal member having a lower end attached to the base portion, and the base portion is Lowering in the reactor pressure vessel and placing the base in the reactor pressure vessel;
A fuel debris retrieval method, characterized in that the fuel debris present in the reactor pressure vessel is cut using the cutting tool of the first work arm. A first elevating device turning mechanism for rotating the first seal elevating device within a predetermined angle range is attached to the fixing member for each of the first seal elevating devices, and rotates the second seal elevating device within a predetermined angle range. A second lifting device turning mechanism is attached to the fixing member for each second seal lifting device;
A state in which the first ring member of the first cylindrical seal member, which is the cylindrical seal member located below the two cylindrical seal members, is held by the first holding members of the plurality of first seal lifting devices. Then, the second cylindrical seal member, which is the other cylindrical seal member positioned above the two cylindrical seal members, is placed on the first cylindrical seal member, and the first cylindrical seal member and the second cylinder are placed on the first cylindrical seal member. Connect the seal members,
The first seal lifting device lowers the first cylindrical seal member together with the connected second cylindrical seal member,
Holding the second ring member of the second cylindrical seal member with the second holding member of each of the plurality of second seal elevating devices;
Thereafter, the first lifting and lowering device turning mechanism is driven to rotate each of the plurality of first seal lifting and lowering devices, and the first holding member of each of the plurality of first seal lifting and lowering devices causes the first extraction method of fuel debris of claim 1 3 for releasing the holding of the first cylindrical seal the first ring member of the member.

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