JP2010071823A - Method for handling control rod drive mechanism - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for handling a control rod drive (CRD) mechanism which makes it possible to reduce exposure doses further. <P>SOLUTION: A CRD cart 41 accommodates an inside tank 43 filled with water 82 in an outside tank 42. A CRD 3 removed from a CRD housing in a reactor pressure vessel is stowed in the inside tank 43 filled with the water 82 and is submerged in it. The inside tank 43 where the CRD 3 is submerged in the water 82 and the outside tank 42 accommodating the inside tank 43 are transported to a CRD repair room. The inside tank 43 is pulled out of the outside tank 42 to the extent of the existence of one end of the former in the latter. The water 82 is filled into the inside tank 43 and the outside tank 42, and the CRD 3 is submerged in the water 82. In this state, the CRD 3 is disassembled and inspected. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for handling a control rod drive mechanism, and more particularly to a method for handling a control rod drive mechanism suitable for application to a control rod drive mechanism used in a boiling water reactor.

  In a boiling water reactor, a reactor core loaded with a plurality of fuel assemblies is disposed in a reactor pressure vessel. The reactor power is controlled by performing a pulling operation (or inserting operation) of the control rod inserted into the core. Such control rod operation is performed by a control rod drive mechanism installed in a control rod drive mechanism housing provided at the bottom of the reactor pressure vessel.

  The control rod drive mechanism is removed from the control rod drive mechanism housing once every few years for inspection after the reactor is shut down. Removal of the control rod drive mechanism from the control rod drive mechanism housing and attachment to the housing is performed using a handling device for the control rod drive mechanism. Examples of this handling apparatus are described in Japanese Patent Application Laid-Open Nos. 11-202085 and 1-97900. Japanese Patent Laid-Open No. 1-97900 further transfers the control rod drive mechanism removed by the control rod drive mechanism handling device to the transport cart, and the control rod drive mechanism is attached to the outside of the reactor containment vessel using the transport cart. It is described to be taken out. The removed control rod drive mechanism is inspected for disassembly. The control rod drive mechanism that has been overhauled is placed in a transport cart and transported to a space in the pedestal that supports the reactor pressure vessel. In this space, the control rod drive mechanism is attached to the control rod drive mechanism housing by the control rod drive mechanism handling device.

  When disassembling and checking the control rod drive mechanism, the control rod drive mechanism is disassembled and cleaned. An example of a control rod drive mechanism disassembly and cleaning apparatus is described in Japanese Patent Application Laid-Open No. 58-60288. This decomposition cleaning apparatus has a decomposition cleaning tank filled with water, a tube holding unit, and a movable carriage. The moving carriage is movably installed in the disassembly and cleaning tank.

JP-A-11-202085 JP-A-1-97900 Japanese Patent Laid-Open No. 58-60288

  The control rod drive mechanism removed from the control rod drive mechanism housing is activated. For this reason, radiation is emitted from the control rod drive mechanism while the removed control rod drive mechanism is transported from the space in the pedestal to the control rod drive mechanism repair chamber for inspection and in the control rod drive mechanism repair chamber. .

  Workers working in the vicinity of the transport path of the control rod drive mechanism and in the control rod drive mechanism repair room are managed so that the exposure dose does not exceed the allowable dose. However, it is also desirable for workers to further reduce the exposure dose.

  Removal of the control rod drive mechanism from the control rod drive mechanism housing and conveyance to the control rod drive mechanism repair chamber of the removed control rod drive mechanism are performed by a handling device of the control rod drive mechanism. It is desired to further reduce the exposure due to the radiation emitted from the control rod drive mechanism during conveyance and the control rod drive mechanism in the control rod drive mechanism repair chamber.

  The objective of this invention is providing the handling method of the control-rod drive mechanism which can further reduce an exposure dose.

  The above-described feature of the present invention is that the inner tank of the control rod drive mechanism transport device having the outer tank and the inner tank that is housed in the outer tank so that it can be pulled out from the outer tank and is filled with water. The control rod drive mechanism removed from the control rod drive mechanism housing of the furnace pressure vessel is housed, and the control rod drive mechanism transport device is connected to the control rod drive mechanism while the control rod drive mechanism is immersed in water in the inner tank. There is to move to the repair room.

  The control rod drive mechanism removed from the control rod drive mechanism housing is transferred to the control rod drive mechanism repair room while being immersed in the water in the inner tank. Is shielded by. Therefore, it is possible to further reduce the exposure dose of the area where the control rod driving device is removed, the area where the control rod driving mechanism is transferred, and the workers around these areas. Further, the control rod drive mechanism removed in the inner tank of the control rod drive mechanism transport device having an outer tank and an inner tank that is housed in the outer tank so that it can be pulled out from the outer tank and is filled with water. Since it is stored, the control rod drive mechanism can be inspected in a state where it is immersed in water in the outer tub and the inner tub drawn from the outer tub. For this reason, since the control rod drive mechanism is not exposed to the outside of the water, the exposure dose of the worker can be further reduced.

  According to the present invention, exposure due to radiation emitted from the control rod drive mechanism removed from the reactor pressure vessel can be further reduced.

  A method for handling a control rod drive mechanism, which is a preferred embodiment of the present invention, will be described below with reference to the drawings. The method of handling the control rod drive mechanism of this embodiment is an example applied to a boiling water reactor. Before explaining this handling method, the schematic structure of the boiling water reactor to which the present embodiment is applied and the structure of the control rod drive mechanism handling apparatus used in the present embodiment will be described first.

  As shown in FIG. 1, the boiling water reactor includes a reactor pressure vessel 1 in which a core (not shown) loaded with a plurality of fuel assemblies is disposed, and a plurality of control rod drive mechanism housings ( (Hereinafter referred to as CRD housing) 4 is installed at the bottom of the reactor pressure vessel 1. A control rod drive mechanism (hereinafter referred to as CRD) 3 is inserted into the CRD housing 4, and a flange 78 of the CRD 3 is attached to a flange 5 provided at a lower end portion of the CRD housing 4 by bolts 6 (FIGS. 2 and 2). 3). A control rod 2 inserted between the fuel assemblies in the core and controlling the reactor power is connected to the upper end of each CRD 3. The CRD 3 that performs each operation of pulling out the control rod 2 from the core and inserting it into the core varies depending on the electrical output of the nuclear power plant having the boiling water reactor, but is provided in the order of a hundred to 200. ing.

  The reactor pressure vessel 1 is installed on a cylindrical pedestal 7. A space 8 formed in the pedestal 7 below the reactor pressure vessel 1 is controlled by a CRD transfer passage 9 and provided outside the reactor containment vessel (not shown) surrounding the reactor pressure vessel 1. Contact is made to a rod drive mechanism repair room (hereinafter referred to as CRD repair room) 10. A guide rail 75 is installed on the ceiling in the CRD repair room 10, and the hoist 11 is movably provided on the guide rail 75.

  A handling device 20 for the control rod drive mechanism is disposed in the space 8. The control rod drive mechanism handling device 20 includes a mast 21, an elevating device 24, a platform (swivel device) 36, and a control rod drive mechanism cart (hereinafter referred to as a CRD cart) 41. The CRD cart 41 is a control rod drive mechanism transport device.

  The platform 36 is placed in a space 8 and placed on a circular rail 65 installed on a plurality of brackets 68 protruding inward from the inner surface of the pedestal 7 (see FIG. 1). At least three wheels 65 provided on the platform 36 are placed on the circular rail 65. As shown in FIG. 4, the platform 36 is formed with an elongated opening 64 passing through the center. A pair of rails 39 arranged with the opening 64 interposed therebetween is installed on the platform 36. A pair of rails 37 and a pair of rails 38 are arranged in parallel with the rails 39 and are installed on the platform 36. A drive device (not shown) for rotating the wheel 65 to turn the platform 36 along the circular rail 65 is provided on the platform 36.

  The mast 21 is provided on the platform 36. Specifically, the mast 21 has a moving carriage (not shown) that is inserted into the opening 64 and moves along the rail 39. The mast 21 is installed on the movable carriage so that it can rotate from a horizontal state to a vertical state. A driving device (not shown) that rotates the mast 21 as described above is installed in the moving carriage of the mast 21. The mast 21 has a space where the CRD cart 41 can be mounted.

  The structure of the lifting device 24 will be described with reference to FIGS. It has movable carriages 25 and 26, support columns 27A and 27B, winches 28 and 29, pulleys 30 and 31, and wires 32 and 33. The movable carriage 25 is movably installed on the rail 37. The movable carriage 25 has wheels placed on the rails 37 and has a driving device (not shown) that rotates the wheels. A support 27 </ b> A and a winch 28 are provided on the movable carriage 25. The support column 27A extends upward from the movable carriage 25. A pulley 30 is provided at the upper end of the column 27A. A wire 32 wound around the winch 28 is hung on the pulley 30 and hangs downward, and a hook 34 is attached to the tip of the wire 32 (see FIG. 6).

  The movable carriage 26 is movably installed on the rail 38. A column 27 </ b> B and a winch 29 are provided on the movable carriage 26. The column 27 </ b> B extends upward from the movable carriage 26. A pulley 31 is provided at the upper end of the column 27B. A wire 33 wound around the winch 29 is hung on the pulley 31 and hangs downward, and a hook 35 is attached to the tip of the wire 33 (see FIG. 6).

  The CRD cart 41 will be described with reference to FIGS. The CRD cart 41 includes an outer tub 42, an inner tub 43, a support plate 46, and electromagnets 47 and 48. The inner tub 43 is disposed in the outer tub 42, and the outer tub 42 and the inner tub 43 have a rectangular cylindrical shape. A lid 44 having a handle 45 that can be opened and closed is provided at one end of the inner tank 43. An inner tank flange 54 is provided on the outer surface of the inner tank 43 at the other end of the inner tank 43 (see FIG. 8). A seal member (for example, an O-ring) 55 is provided around the inner tank flange 54. When the inner tub 43 is present in the outer tub 42, the seal member 55 is in contact with the three inner surfaces of the outer tub 42 and maintains airtightness on these three surfaces.

  A lid 79 is detachably attached to the end surface of the outer tub 42 on the lid 44 side. A side plate 80 disposed at a position on the upper surface of the outer tub 42 in a roll-over state is also detachably attached to the outer tub 42. An end surface of the outer tub 42 on the inner tub flange 54 side is sealed with a rectangular plate member 83. A pin 76 having a stopper 67 </ b> A and a pin 77 having a stopper 67 </ b> B are attached to the plate member 83, and extend into the inner tub 43 accommodated in the outer tub 42. In a state where the inner tank 43 is completely stored in the outer tank 42, the tip portions of the pins 76 and 77 and the stoppers 67 </ b> A and 67 </ b> B are located in the inner tank 43. Wheels 51 </ b> A, 51 </ b> B, and 51 </ b> C are rotatably provided at a portion of the outer tub 42 that is on the lower side when it is rolled over. The wheels 51A, 51B and 51C are arranged outside the outer tub 42.

  The end of the inner tub 43 provided with the inner tub flange 54 is open, and the inner tub 43 communicates with a region in the outer tub 42 formed between the inner tub flange 54 and the plate member 83. Yes.

  A water supply pipe 58 provided with a water supply valve 59, a drain pipe 60 provided with a drain valve 61, and a vent pipe 62 provided with a vent valve 63 are provided on the plate member 83. The water supply pipe 58, the drain pipe 60, and the vent pipe 62 are connected to a region in the inner tank 43. In a state where the CRD cart 41 rolls over, the water supply pipe 58 and the vent pipe 62 are attached to the upper end portion of the plate member 83, and the drain pipe 60 is attached to the lower end portion of the plate member 83. Electromagnets 47 and 48 are provided on the outer surface of the outer tub 42 on the plate member 83 side of the outer tub 42.

  A support plate 46 that supports the CRD flange 78 in a state where the CRD cart 41 is upright is disposed in the inner tank 43. An opening is formed in the support plate 46 so that a portion of the CRD 3 below the CRD flange 78 is inserted. In a state where the support plate 46 holds the lower end portion of the CRD 3, the pins 76 and 77 penetrate the support plate 46, and the support plate 46 is in contact with the stoppers 67A and 67B. Wheels 52A, 52B, 52C and wheels 53A, 53B, 53C are provided outside the inner tank 43. In a state where the CRD cart 41 is rolled over, the wheels 52A, 52B, and 52C are located on the lower side, and are in contact with the inner surface of the lower portion of the outer tub 42. In this state, the wheels 53 </ b> A, 53 </ b> B, and 53 </ b> C are located on the upper side and are in contact with the inner surface of the upper portion of the outer tub 42. The wheels 52 </ b> A and 53 </ b> A, the wheels 52 </ b> B and 53 </ b> B, and the wheels 52 </ b> C and 53 </ b> C are pressed against the corresponding inner surface of the outer tub 42 by the spring member 66. The electromagnets 47 and 48 are arranged so as to face the support plate 46 in a state where the pins 76 and 77 are inserted.

  In a state where the CRD cart 41 rolls over, a plurality of pedestals 57 that support the CRD 3 housed in the inner tank 43 are installed side by side on one inner surface of the inner tank 43. The pedestal 57 is attached to a torsion coil spring 56 installed on the inner surface of the inner tank 43 as shown in FIG. When a pushing force is applied to the cradle 57 (see FIG. 9A), the cradle 57 is tilted to the inner surface side of the inner tank 43 by the action of the torsion coil spring 56 (see FIG. 9B). When the pushing force does not act on the cradle 57, the cradle 57 is returned to the original state, that is, the state perpendicular to the inner surface of the inner tank 43 (see FIG. 9A) by the torsion coil spring 56. It is. A side plate 81 disposed at a position on the upper surface of the inner tub 43 in a roll-over state is detachably attached to the inner tub 43.

  When the CRD flange 78 hits the cradle 57 when the mast 21 to which the CRD cart 41 is mounted is in an upright state and the CRD 3 removed from the CRD housing 4 is inserted into the inner tub 43, the cradle 57 is twisted by the torsion coil spring 56. It is brought down to the inner surface side of the inner tank 43 by the action. This greatly contributes to smooth storage of the CRD 3 in the inner tank 43. After the CRD flange 78 passes, the cradle 57 is returned to a state perpendicular to the inner surface of the inner tank 43 by the action of the torsion coil spring 56. In a state where the CRD cart 41 is rolled over, the CRD 3 in the inner tub 43 is supported by the cradle 57. When inserting the CRD 3 into the CRD housing 4 from the inner tub 43 with the mast 21 in the upright state, the cradle 57 is pushed upward by the CRD flange 78. At this time, the cradle 57 falls to the opposite side to the case where it is pushed downward, and after the CRD flange 78 passes, it returns to the original state by the action of the torsion coil spring 56.

  A method of handling the control rod drive mechanism of this embodiment using the control rod drive mechanism handling device 20 will be described below. In a boiling water reactor, a periodic inspection is usually performed after the operation of one operation cycle is completed and the operation of the reactor is stopped. The work item of this periodic inspection includes an overhaul of CRD3. In performing the overhaul of the CRD 3, it is necessary to remove the CRD 3 attached to the CRD housing 4 and transport it to the CRD repair room 10. Removal and conveyance of the CRD 3 are performed by the handling device 20 of the control rod drive mechanism.

  A CRD car and 41 that do not store the CRD 3 in the inner tank 43 are placed in the CRD repair room 10 (see FIG. 11). The inner tank 43 accommodated in the outer tank 42 has a lid 44 and a side plate 81 attached thereto. A lid 79 and a side plate 80 are also attached to the outer tub 42 to seal the outer tub 42. The vent valve 63 is opened and the drain valve 61 is closed. The water supply hose 69 is connected to the water supply pipe 58 and the water supply valve 59 is opened. Water 82 is supplied into the inner tank 43 through the water supply hose 69 and the water supply pipe 58. When the water 82 overflows from the vent pipe 62, the supply of the water 82 is stopped and the water supply valve 59 and the vent valve 63 are closed.

  While the mast 21 is turned over, the platform 36 is turned so that the mast 21 is aligned with the CRD transport passage 9 (see FIG. 12). At this time, the lifting / lowering device 24 exists at an arbitrary position on the rails 37 and 38 apart from the mast 21. The CRD cart 41 in which the water 82 is filled in the inner tank 43 is stored in the mast 21 through the CRD carry-in / out passage 10 (see FIG. 13). A pair of power supply connectors 22 is provided at the bottom of the mast 21 (see FIG. 6). When the CRD cart 41 is mounted on the mast 21, each connector 49 (see FIG. 6) provided on the electromagnets 47 and 48 of the CRD cart 41 is connected to each power supply connector 22. Each power connector 22 is connected to a power source by a cable 23.

  The driving device provided on the moving carriage of the mast 21 is driven to rotate the mast 21 so that the overturned mast 21 is brought into an upright state. Thereafter, the moving carriage of the mast 21 is moved along the rail 39, and the mast 21 in the upright state is moved to a position just below the CRD 3 to be removed and positioned (see FIG. 14). The lid 79 installed at the upper end of the outer tub 42 and the lid 44 installed at the upper end of the inner tub 43 are removed. Water 82 is filled in the inner tank 43 and between the inner tank 43 and the outer tank 42. Water may be supplied in the inner tank 43 and between the inner tank 43 and the outer tank 42 so as to be full.

  The movable carriages 25 and 26 are moved along the rails 37 and 38, and the lifting device 24 is moved to the side of the mast 21 that is positioned (see FIGS. 15A and 15B). The wire 32 wound around the winch 28 is unwound by the rotation of the winch 28 and is hung from the pulley 30 into the inner tank 43 of the CRD cart 41. The hook 34 attached to the tip of the wire 32 descends to the lower end in the inner tank 43. When the hook 34 is lowered into the inner tank 43, in order to prevent the hook 34 from interfering with the support plate 46, an electric current is supplied to the electromagnet 47 to activate the electromagnet 47, and the hook 34 is moved inside the inner tank 43. Pull to the side. The hook 34 is lowered to the lower end portion of the inner tank 43 without interfering with the support plate 46 while being attracted to the electromagnet 47 side.

  The wire 33 wound around the winch 29 is also unwound by the rotation of the winch 29 and is hung from the pulley 31 into the inner tank 43 of the CRD cart 41. The hook 35 attached to the tip of the wire 33 descends to the lower end in the inner tank 43. Similarly to the hook 34, the hook 35 is lowered to the lower end portion of the inner tank 43 without interfering with the support plate 46 while being attracted to the electromagnet 48 operating in the inner tank 43.

  When the hooks 34 and 35 are lowered to the lower end of the inner tank 43, the supply of current to the electromagnets 47 and 48 is stopped. Since the electromagnets 47 and 48 are not functioning, the hooks 34 and 35 are completely suspended.

  By rotating the winches 25 and 26, the wires 32 and 33 are wound up, and the hooks 34 and 35 in a freely suspended state are raised. By this operation, the hooks 34 and 35 are hooked on both ends of the support plate 46, respectively. By further winding the wires 32 and 33 with the winches 25 and 26, the support plate 46 is lifted and disengaged from the pins 76 and 76 (see FIG. 16). When the hooks 34 and 35 are hooked on the support plate 46, the load of the support plate 46 is applied to the wires 32 and 33, and a tensile force is generated on the wires 32 and 33. By detecting this pulling force, it can be known that the hooks 34 and 35 are reliably hooked on the support plate 46. The tensile force can be detected by installing a load meter (not shown) on the winches 28 and 29 (or the pulleys 30 and 31). By further winding the wires 32 and 33 by the winches 28 and 29, the support plate 46 is further raised, and the support plate 46 eventually comes into contact with the CRD flange 78 of the CRD 3 attached to the CRD housing 4 (FIG. 17). reference). When the support plate 46 comes into contact with the CRD flange 78, the winding of the wires 32 and 33 by the winches 28 and 29 is stopped, and the ascent of the support plate 36 is stopped.

  With the support plate 46 in contact with the CRD flange 78, the bolt 6 connecting the CRD 3 and the CRD housing 4 is removed. The removal work of the bolt 6 is performed by an operator. When all the bolts 6 are removed, the load of the CRD 3 is applied to the support plate 46, and a further tensile force is applied to the wires 32 and 33. This tensile force can be measured by a load meter provided on the winches 28 and 29. The winches 28 and 29 are rotated to rewind the wires 32 and 33. By this operation, the support plate 46 is lowered, the CRD 3 is pulled out from the CRD housing 4, and the pulled out CRD 3 is inserted into the inner tank 43 of the CRD cart 41 (see FIG. 18). The inner tank 43 of the CRD cart 41 is filled with water 82, and the extracted CRD 3 is immersed in the water 82 in the inner tank 43.

  By further rotating the winches 28 and 29 to rewind the wires 32 and 33, the support plate 46 and the CRD 3 are further lowered. When the support plate 46 comes into contact with the stoppers 67A and 67B provided on the pins 76 and 77, the CRD 3 completely extracted from the CRD housing 4 is stored in the CRD cart 41, that is, the inner tank 43. (See FIG. 19). After the support plate 46 comes into contact with the stoppers 67A and 67B provided on the pins 76 and 77, the winches 28 and 29 until the hooks 34 and 35 are released from the support plate 46 until the wires 32 and 33 are loosened. Rotation stops driving. For this reason, the hooks 34 and 35 are detached from the support plate 46.

  A current is supplied to the electromagnets 47 and 48 to make the electromagnets 47 and 48 work. As a result, the hook 34 is pulled toward the electromagnet 47 in the inner tank 43, and the hook 35 is pulled toward the electromagnet 48 in the inner tank 43. The winches 28 and 29 are rotated to wind the wires 32 and 33 while the hooks 34 and 35 are pulled toward the corresponding electromagnets. The hooks 34 and 35 are smoothly pulled up in the inner tank 43 without being interfered with the support plate 46. Eventually, the hooks 34 and 35 are pulled out from the CRD cart 41.

  When the hooks 34 and 35 are completely pulled out from the CR cart 41, the winding of the wires 32 and 33 by the winches 28 and 29 is stopped. Thereafter, the upper end of the inner tank 43 is sealed with a lid 44, and the upper end of the outer tank 42 is also sealed with a lid 79 (see FIG. 20). As a result, the activated CRD 3 is enclosed in the CRD cart 41 while being immersed in the water 82 in the inner tank 43 of the CRD cart 41. For this reason, the radiation emitted from the CRD 3 is shielded by the water 82. Since the radiation is shielded by the water 82, the operation of attaching the lid 79 to the outer tub 42 can be performed by an operator.

  After the lid 79 is attached to the outer tub 42, the lifting device 24 is moved along the rail 39 from the side of the mast 21 to a position where it does not interfere with the subsequent work (see FIG. 21). The platform 36 is turned so that the opening 64 of the platform 36 is aligned with the CRD loading / unloading passage 9 (see FIG. 21). The mast 21 is turned over and the CRD cart 41 is taken out of the mast 21. The CRD cart 41 is moved to the CRD repair room 10 through the CRD carry-in / out passage 9 (see FIG. 22). The CRD cart 41 is lifted by the hoist 11, stacked, and stored in the CRD repair room 10 (see FIG. 23). Thus, the activated CRD 3 is stored without being taken out of the CRD cart 41 and confined in the CRD cart 41.

  The overhaul of CRD3 in the CRD repair room 10 is demonstrated using FIG.24 and FIG.25. The overhaul of the CRD 3 in this embodiment is performed while the CRD 3 is stored in the CRD cart 41.

  The CRD cart 41 containing the CRD 3 in the filled water 82 is placed horizontally on the support base (or floor) 84 (see FIG. 24A). The vent valve 63 is opened, and then the drain valve 61 is opened. As a result, water existing between the inner tank 43 and the outer tank 42 is discharged through the drain pipe 60. Thereafter, the side plate 80 of the outer tub 42 is removed, and the side plate 81 of the inner tub 43 is also removed. The lid 79 is removed from the outer tub 42. As shown in FIG. 25, the water supply hose 69 connected to the pump 71 is connected to the water supply pipe 58.

  Thereafter, the worker holds the handle 45 of the lid 49 attached to one end of the inner tank 43 and pulls it horizontally to pull out the inner tank 43 containing the CRD 3 from the outer tank 42 (see FIG. 24B). ). When the inner tank 43 is pulled out from the outer tank 42, the wheels provided in the inner tank 43 such as the wheels 52 </ b> C are pressed against the upper surface of the support base 84 by the action of the spring member 66. Since the wheels 52A, 52B, and 52C are provided, the inner tank 43 can be easily pulled out from the outer tank 42 in the horizontal direction. When the inner tank 43 is pulled out, the water supply hose 68 and the water supply pipe are driven by driving the pump 71 in order to avoid that the water level of the water 82 in the outer tank 42 and the inner tank 43 is lowered and the CRD 3 is exposed on the water surface. Water is supplied into the outer tub 42 through 58. The supplied water 82 is also supplied into the inner tank 43 from the open end of the inner tank 43 provided with the inner tank flange 54. A water level meter is installed in the inner tank 43, and the water level of the inner tank 43 in a horizontally placed state is measured with this water level meter using the measured value of the water level gauge. It is also possible to control the water level in the outer tub 42 and the inner tub 43 to a predetermined value by controlling the opening of the water supply valve 59 using. Since the sealing member 55 provided on the inner tank flange 54 secures the sealing property between the inner surface of the outer tank 42, the water 82 in the outer tank 42 and the inner tank 43 flows between the outer tank 42 and the inner tank 43. Leakage to the outside through the gap is prevented. When the inner tank flange 54 hits a stopper (not shown) provided at the end of the outer tank 42 to which the lid 79 is attached, the drawing operation of the inner tank 43 is stopped.

  The support plate 46 supporting the end of the CRD 3 on the CRD flange 78 side is moved in the horizontal direction in the outer tub 42. The CRD 3 moves by sliding on the cradle 57, and the CRD 3 can be arranged at any position in the inner tank 43 and the outer tank 42 (see FIG. 24C). The CRD 3 is immersed in the water 82 in the outer tank 42 and the inner tank 43. In this state, the worker performs an overhaul of the CRD 3 in the CRD cart 41 extended as described above. After the overhaul of the CRD 3 is completed, the inner tank 43 in which the overhauled CRD 3 is accommodated is moved toward the outer tank 42 and is accommodated in the outer tank 42. While the inner tank 43 is housed in the outer tank 42, the vent valve 61 is opened and the water in the outer tank 42 is discharged through the vent pipe 60. As shown in FIG. 25, the vent pipe 60 is connected to a drain hose 72 connected to a tank 73. The discharged water 82 is discharged to the tank 73. The water 82 is discharged so that the water level of the water 82 in the inner tank 43 is maintained at a predetermined value at which the CRD 3 is not exposed on the water surface. After the inner tank 43 is stored in the outer tank 42, the side plate 81 is attached to the inner tank 43, and the lid 79 and the side plate 80 are attached to the outer tank 42. The CRD 3 that has been disassembled and inspected is immersed in the water 82 in the inner tank 43.

  The operation of attaching the CRD 3 to the CRD housing 4 after the overhaul is completed is performed in the reverse order of the above-described removal process of the CRD 3 from the CRD housing 4 and the transport process of the CRD cart 41 to the CRD repair room 10. The CRD 3 that has been disassembled and inspected is moved to a position just below the CRD housing 4 to be attached by the CRD cart 41 and the mast 21 while being immersed in the water 82 in the inner tank 43.

  When the CRD repair room 10 is used for other purposes and the CRD 3 removed from the CRD housing 4 cannot be immediately disassembled and checked in the CRD repair room 10, the CRD 3 is stored for a certain period of time. The storage of the CRD 3 in this case will be described.

  The removed CRD 3 is stored in the CRD repair room 10 while being stored in the CRD cart 41. During storage of the CRD 3, the water supply pipe 58 provided in the outer tub 42 is connected to the water supply hose 69 and connected to the pump 71. The drain pipe 60 is connected to a drain hose 72 and connected to a tank 73. The water supply valve 59 and the drain valve 61 are opened and the pump 71 is driven to supply water into the inner tank 43. The water in the inner tank 43 is discharged into the tank 73 through the drain pipe 60 and the drain hose 72. Thus, since water is supplied into the inner tank 43 during storage of the CRD 3, the CRD 3 in the inner tank 43 can be stored in a clean state. When the CRD 3 can be overhauled in the CRD repair room 10, the CRD 3 stored in the CRD cart 41 is extended in the CRD repair room 10 as shown in FIG. The cart 41 is overhauled and inspected.

  In this embodiment, the activated CRD 3 removed from the CRD housing 4 is stored in a CRD cart 41 filled with water 82, specifically, an inner tank 43 and immersed in water 82. Therefore, the radiation emitted from the stored CRD 3 can be shielded by the water 82 in the inner tank 43. For this reason, while the CRD cart 41 containing the CRD 3 falls from the upright state and is transported to the CRD repair room 10, each worker working in the surrounding area is exposed to radiation emitted from the removed CRD 3. Can be prevented. In addition, each worker is exposed to radiation emitted from the CRD 3 even while the CRD 3 that has been disassembled is stored in the CRD cart 41 and transported directly from the CRD repair chamber 10 to the CRD housing 4 to be attached. Can be prevented.

  In this embodiment, the CRD cart 41 has an outer tub 42 and an inner tub 43, and the outer tub 42 and the inner tub 43 are pulled out from the outer tub 42 without separating the outer tub 42 and the inner tub 43. The CRD 3 is immersed in water 82 filled in the tank 43 and the CRD 3 is inspected for disassembly. For this reason, the CRD 3 that has been immersed and transported in the water 82 in the inner tank 43 can be disassembled and inspected in the extended CRD cart 41 without taking it out into the air. Therefore, it is possible to further reduce the exposure of workers in the overhaul of the CRD 3 in the CRD repair room 10. If a space for extending the inner tank 43 from the outer tank 42 can be secured by using the CRD cart 41 having the outer tank 42 and the inner tank 43, a plurality of CRD carts 41 are arranged and a plurality of CRDs 3 are inspected in parallel. Can be done. Since a plurality of CRDs 3 can be disassembled and inspected in parallel, the period required for disassembling and inspection can be shortened.

  In this embodiment, the electromagnets 47 and 48 are attached to the CRD cart 41, but the electromagnets 47 and 48 may be attached to the mast 21. In this case, the electromagnets 47 and 48 are always connected to the power supply connector 22.

It is a block diagram of the handling apparatus of the control-rod drive mechanism used for the handling method of the control-rod drive mechanism in a boiling water reactor which is one suitable Example of this invention. It is explanatory drawing which shows the attachment state of the control-rod drive mechanism to the control-rod drive mechanism housing of a boiling water reactor. It is a block diagram when the control rod drive mechanism shown in FIG. 2 is viewed from below. It is a top view of the platform shown in FIG. It is a front view of the raising / lowering apparatus shown in FIG. It is an enlarged view of the V section of FIG. FIG. 2 is a configuration diagram of the control rod drive mechanism cart shown in FIG. 1, (A) is a plan view of the control rod drive mechanism cart, and (B) is a front view of the control rod drive mechanism cart. (C) is a side view of the control rod drive mechanism cart. FIG. 8 is an enlarged view of a portion VIII in FIG. It is an enlarged view of the IX part of Drawing 7 (B). FIG. 8 is an enlarged view of a portion X in FIG. It is explanatory drawing which shows the state by which the control-rod drive mechanism cart filled with water was placed in the control-rod drive mechanism repair room. It is explanatory drawing which shows the state which turned the mast rolled over by the turning of a platform in the direction of the control-rod drive mechanism conveyance path. It is explanatory drawing which shows the state which mounted | wore the mast with the control-rod drive mechanism cart. It is explanatory drawing which shows the state which rotated the mast with which the control-rod drive mechanism cart was mounted to the upright state. (A) is a front view of a state where the lifting device is positioned beside the mast, and (B) is a side view in any state. It is explanatory drawing which shows the state which wound up the wire to which the hook is attached, and moved the support plate which mounts a control-rod drive mechanism upward. It is explanatory drawing which shows the state which made the support plate contact the control-rod drive mechanism flange. It is explanatory drawing in the middle stage which lowered | hung the control-rod drive mechanism removed from the control-rod drive mechanism housing. It is explanatory drawing which shows the state which accommodated the removed control rod drive mechanism completely in the control rod drive mechanism cart filled with water. It is explanatory drawing which shows the state which sealed the upper end of the control-rod drive mechanism cart which accommodated the control-rod drive mechanism. It is explanatory drawing which shows the state which separated | separated the raising / lowering apparatus from the mast which mounted | wore with the control rod drive mechanism cart which accommodated the control rod drive mechanism. It is explanatory drawing which shows the state which rolled over the mast which mounted | wore with the control rod drive mechanism cart, and moved this control rod drive mechanism cart to the control rod drive mechanism repair room. It is explanatory drawing which shows the state which has transferred the control-rod drive mechanism cart which accommodated the control-rod drive mechanism in the control-rod drive mechanism repair room using the hoist. It is explanatory drawing which shows the decomposition | disassembly inspection of a control rod drive mechanism, (A) is explanatory drawing which shows the state which put the control rod drive mechanism cart which accommodated the control rod drive mechanism on the support stand, (B) is control rod drive Explanatory drawing which shows the state which pulled out the inner tank which accommodated the mechanism to the exterior of an outer tank, (C) is the state which has arrange | positioned the control-rod drive mechanism which performs a disassembly inspection in the inner tank and the outer tank in the appropriate position. It is explanatory drawing shown. It is explanatory drawing which shows the storage state of the control-rod drive mechanism cart which accommodated the control-rod drive mechanism.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Reactor pressure vessel, 2 ... Control rod, 3 ... Control rod drive mechanism, 4 ... Control rod drive mechanism housing, 7 ... Pedestal, 9 ... Control rod drive mechanism carrying-in / out passage, 10 ... Control rod drive mechanism repair room, DESCRIPTION OF SYMBOLS 20 ... Handling apparatus of control rod drive mechanism, 21 ... Mast, 24 ... Elevating device, 25, 26 ... Moving cart, 27A, 27B ... Strut, 28, 29 ... Winch, 30, 31 ... Pulley, 32, 33 ... Wire, 34, 35 ... hook, 36 ... platform, 41 ... control rod drive mechanism cart, 42 ... outer tub, 43 ... inner tub, 44, 79 ... lid, 46 ... support plate, 47, 48 ... electromagnet, 51A, 51B, 51C , 52A, 52B, 52C ... wheels, 57 ... cradle, 59 ... water supply valve, 61 ... drain valve, 63 ... vent valve, 82 ... water.

Claims (6)

  A control rod for a reactor pressure vessel in the inner tub of the control rod drive mechanism transport device having an outer tub and an inner tub that is housed in the outer tub and is filled with water so that it can be pulled out from the outer tub The control rod drive mechanism removed from the drive mechanism housing is housed, and the control rod drive mechanism transport device is moved to the control rod drive mechanism repair chamber in a state where the control rod drive mechanism is immersed in the water in the inner tank. A method of handling a control rod drive mechanism, wherein the control rod drive mechanism is moved.   The inner tank filled with the water in the control rod drive mechanism repair chamber is pulled out from the outer tank leaving a part, and the control rod drive mechanism in the outer tank and the water in the inner tank The handling method of the control-rod drive mechanism of Claim 1 which performs disassembly inspection of this.   Water is supplied into the inner tank of the control rod drive mechanism transfer device moved to the control rod drive mechanism repair room, and the control rod drive mechanism transfer device is stored by discharging the water in the inner tank. The method of handling a control rod drive mechanism according to claim 1.   In the control rod drive mechanism repair chamber, the inner tank filled with the water of the stored control rod drive mechanism transport device is withdrawn from the outer tank, leaving a part of the inner tank and the inner tank. The method of handling a control rod drive mechanism according to claim 1, wherein the control rod drive mechanism is disassembled and inspected in the water in the tank. The mast that rotates from the horizontal state to the vertical state of the swivel device arranged below the reactor pressure vessel is housed in the outer tank and filled with water so that it can be pulled out from the outer tank. A control rod drive mechanism carrying device having an inner tank is mounted,
The control rod drive mechanism removed from the control rod drive mechanism housing of the reactor pressure vessel is accommodated in the water in the inner tank of the control rod drive mechanism transfer device which is in a state perpendicular to the swivel device. And
With the mast overturned, with the control rod drive mechanism immersed in the water in the inner tank, the control rod drive mechanism transport device is removed from the mast,
A method of handling a control rod drive mechanism, wherein the control rod drive mechanism transport device taken out of the mast is moved to a control rod drive mechanism repair chamber.   The inner tank filled with the water in the control rod drive mechanism repair chamber is pulled out from the outer tank leaving a part, and the control rod drive mechanism in the outer tank and the water in the inner tank The method for handling a control rod drive mechanism according to claim 5, wherein an overhaul is performed.

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