JP6793212B2 - How to carry out nuclear fuel material in a nuclear plant - Google Patents

Description

The present invention relates to a method for carrying out nuclear fuel material in a nuclear power plant, and more particularly to a method for carrying out nuclear fuel material in a nuclear power plant suitable for application to a boiling water reactor and a pressurized water reactor.

In nuclear power plants such as boiling water reactors and pressurized water reactors, a plurality of fuel assemblies containing nuclear fuel material are loaded into the core of a nuclear reactor. The fuel assembly that has experienced the operation of the reactor in a predetermined number of operation cycles after being loaded in the core is carried out from the inside of the reactor as a spent fuel assembly to the outside of the reactor.

An example of a method for carrying out a spent fuel assembly from a nuclear reactor in a boiling water reactor is described in Japanese Patent Application Laid-Open No. 8-262182. The spent fuel assembly is taken out of the reactor using a refueling machine movably installed on the cab inside the reactor building and transported to the fuel storage pool formed inside the reactor building.

Japanese Unexamined Patent Publication No. 8-262182

In the method of transporting the used fuel assembly from the reactor described in JP-A-8-262182, the nuclear fuel material in the reactor of the boiling water reactor is present in the sound fuel assembly. In some cases, this is a method of carrying out the spent fuel assembly from the core. However, in the unlikely event that the nuclear fuel material contained in the fuel assembly loaded in the core of the nuclear reactor melts, as in the nuclear plant of the Three Mile Nuclear Power Station, this melted nuclear fuel material It is extremely difficult to carry out the nuclear fuel material from the nuclear reactor, and it takes a long time to carry out the melted and solidified nuclear fuel material.

An object of the present invention is to provide a method for carrying out nuclear fuel material in a nuclear power plant, which can carry out the molten nuclear fuel material in a shorter time.

The feature of the present invention that achieves the above-mentioned object is formed in a rotating body provided on the front surface with a plurality of cutter devices for cutting nuclear fuel material, a propulsion unit having a plurality of propulsion jacks for advancing the rotating body, and a propulsion unit. Using a shield cutting device with a transfer passage for transferring the cut nuclear fuel material, the cutting of the nuclear fuel material in the nuclear fuel material presence area in the reactor vessel is performed by multiple cutter devices that are swiveled by the rotation of the rotating body. The advancement of the rotating body is carried out by multiple propulsion jacks, and the cut nuclear fuel material is transferred through the transfer passage.

The cutting of the nuclear fuel material in the area where the nuclear fuel material exists in the reactor vessel is performed by multiple cutter devices that are swiveled by the rotation of the rotating body of the shield cutting device, and the advancing of the rotating body is performed by multiple propulsion jacks. Since the cut nuclear fuel material is transferred through the transfer passage, even if the nuclear fuel material in the core is melted, the nuclear fuel material can be carried out in a shorter time.

According to the present invention, the molten nuclear fuel material can be carried out in a shorter time.

It is explanatory drawing which shows the installation state of the house and the crane apparatus used for the method of carrying out the nuclear fuel material in the nuclear power plant of Example 1, which is a preferable example of this invention. It is a top view of the bottom of the house shown in FIG. FIG. 5 is an explanatory diagram showing a state in which the boring device is arranged on the opening / closing type shielding member in the house in the first embodiment. FIG. 3 is a sectional view taken along line IV-IV of FIG. FIG. 5 is an explanatory view showing a state in which a power connector is connected to the boring device and a hole is formed in the upper lid of the reactor pressure vessel in the first embodiment. It is a detailed block diagram of the boring apparatus shown in FIG. It is a top view of the boring apparatus shown in FIG. FIG. 6 is an enlarged view of the vicinity of the inner blade shaft drive socket of the boring device shown in FIG. 6 is an enlarged vertical sectional view of a cutting device and an extension tube used in the boring device shown in FIG. 6, FIG. 6A is an enlarged vertical sectional view of the cutting device, and FIG. 6B is an enlarged vertical sectional view of the extension tube. FIG. 6 is an enlarged vertical sectional view showing a connection state and a separated state of the cutting device and the extension pipe of the boring device shown in FIG. 6, and FIG. 6A is an enlarged vertical sectional view showing the separated cutting device and the extension pipe, (B). ) Is an enlarged vertical sectional view showing a connected cutting device and an extension pipe. It is explanatory drawing which shows the state which held the extension tube by the extension tube moving device of the boring device shown in FIG. It is explanatory drawing which shows the process of the first half of the procedure of connecting an extension pipe to a cutting apparatus. It is explanatory drawing which shows the process of the latter half of the procedure of connecting an extension pipe to a cutting apparatus. It is explanatory drawing which shows the process of the first half of the procedure of pulling out a rotary shaft from each outer cylinder of the cutting apparatus and extension pipe which are inserted and connected in a reactor pressure vessel. It is explanatory drawing which shows the latter half of the procedure of pulling out a rotary shaft from each outer cylinder of a cutting apparatus and an extension pipe which are inserted and connected in a reactor pressure vessel. FIG. 5 is an explanatory diagram showing a state in which a camera is inserted into the upper end of a reactor pressure vessel and holes are made in a steam dryer and a steam separator using a boring device in the first embodiment. FIG. 5 is an explanatory diagram showing a state in which a camera is inserted between the steam separator and the core through holes formed in the steam dryer and the steam separator in the first embodiment. It is explanatory drawing which shows the state which iron ball and iron powder were injected into the core. It is explanatory drawing which shows the process of the first half of the procedure of pulling out each outer cylinder which is inserted and connected in a reactor pressure vessel from a reactor pressure vessel. It is explanatory drawing which shows the latter half of the procedure of pulling out each outer cylinder which is inserted and connected into a reactor pressure vessel from a reactor pressure vessel. It is explanatory drawing which shows the state which installed the guide rail and the turntable on the bottom of the house shown in FIG. It is explanatory drawing which shows the carrying-out of the upper lid of the reactor containment vessel performed in Example 1. FIG. It is explanatory drawing which shows the cutting process of the upper cover in the process of carrying out the upper cover of the reactor containment vessel shown in FIG. It is explanatory drawing which shows the carrying-out process of the upper lid in the carrying-out process of the upper lid of the reactor containment vessel shown in FIG. It is explanatory drawing which shows the carry-out of the steam separator performed in Example 1. FIG. It is explanatory drawing which shows the cutting of the steam separator in the carry-out process of the steam separator shown in FIG. It is explanatory drawing which shows the carry-out of the water supply spurger performed in Example 1. FIG. It is a detailed block diagram of the elastic water jet apparatus used for cutting the constituent member performed in Example 1. FIG. FIG. 5 is an explanatory diagram showing a state in which another type of boring device is installed in a reactor pressure vessel in the first embodiment. It is a detailed block diagram of the boring apparatus shown in FIG. It is a top view of the boring apparatus shown in FIG. FIG. 30 is an enlarged vertical sectional view of a cutting device used in the boring device shown in FIG. It is a top view of the boring apparatus shown in FIG. FIG. 9 is a cross-sectional view taken along the line XX shown in FIG. It is explanatory drawing which shows the process of connecting an extension pipe to the cutting apparatus shown in FIG. It is explanatory drawing which shows the carry-out of the nuclear fuel material existing in the core performed in Example 1. FIG. It is explanatory drawing which shows the injection state of iron powder (shielding powder) into the core performed after the nuclear fuel material is carried out from the core in Example 1. FIG. It is explanatory drawing which shows the boring performed toward the furnace bottom part using the boring apparatus in Example 1. FIG. It is explanatory drawing which shows the injection state of the iron powder on the molten nuclear fuel material which fell to the furnace bottom part performed in Example 1. FIG. It is explanatory drawing which shows the cutting of the core shroud performed after the iron powder injection shown in FIG. 39. It is explanatory drawing which shows the carry-out of the nuclear fuel material which fell to the furnace bottom part performed in Example 1. FIG. It is explanatory drawing which shows the injection state of iron powder to the furnace bottom part performed after the nuclear fuel material was carried out from the furnace bottom part performed in Example 1. FIG. It is explanatory drawing which shows each state of boring performed downward from the reactor pressure vessel and iron powder injection performed below the reactor pressure vessel using the boring device in Example 1. It is explanatory drawing which shows the cutting of the core shroud lower body performed in Example 1. FIG. It is explanatory drawing which shows the carry-out of the nuclear fuel material which fell to the bottom of the reactor containment vessel performed in Example 1. FIG. It is explanatory drawing which shows the cutting and carrying-out of the reactor pressure vessel performed in Example 1. FIG. It is explanatory drawing which shows the state after carrying out the reactor pressure vessel in Example 1. FIG. It is explanatory drawing which shows the boring of the reactor pressure vessel by the boring apparatus performed at the time of carrying out the nuclear fuel material when the nuclear fuel material in the reactor pressure vessel and the structure in the reactor are melted in Example 1. FIG. It is explanatory drawing which shows the injection state of iron powder on the molten nuclear fuel material of the furnace bottom part performed at the time of carrying out the nuclear fuel material when the nuclear fuel material in a reactor pressure vessel and the structure in a furnace are melted in Example 1. FIG. .. It is explanatory drawing which shows the unloading of the equipment which remains in a reactor pressure vessel performed at the time of carrying out the nuclear fuel material in the case where the nuclear fuel material in a reactor pressure vessel and the structure in a reactor are melted in Example 1. FIG. FIG. 5 is an explanatory diagram showing the removal of the molten nuclear fuel material existing at the bottom of the reactor, which is performed at the time of carrying out the nuclear fuel material when the nuclear fuel material and the structure inside the reactor are melted in the first embodiment. It is explanatory drawing which shows the unloading of the molten nuclear fuel material which fell to the bottom of the reactor containment vessel performed at the time of carrying out the nuclear fuel material when the nuclear fuel material in a reactor pressure vessel and the structure in a reactor are melted in Example 1. FIG. .. It is explanatory drawing which shows the state in which the boring device which is performed in the method of carrying out the nuclear fuel material in the nuclear power plant of Example 2 which is another Example of this invention is arranged on the opening and closing type shielding member. FIG. 2 is an explanatory diagram showing a state in which a camera is inserted into the upper end of a reactor pressure vessel and holes are made in a steam dryer and a steam separator using a boring device in the second embodiment. It is explanatory drawing which shows the state in which the camera is inserted between the steam separator and the core through the hole made in the steam dryer and the steam separator in Example 2. FIG. It is explanatory drawing which shows the installation state of the house and the crane apparatus used in Example 2. FIG. It is explanatory drawing which shows the installation state of the shield excavation apparatus used for the method of carrying out the nuclear fuel material in the nuclear power plant of Example 3 which is another Example of this invention. It is explanatory drawing which shows the cutting of the structure in the reactor pressure vessel by using the shield excavator in Example 3. FIG. FIG. 5 is an explanatory diagram showing a state in which cutting of a structure in a reactor pressure vessel is completed using a shield excavator in the third embodiment.

Examples of the present invention will be described below.

A method for carrying out the nuclear fuel material in the nuclear power plant of Example 1 applied to a boiling water reactor, which is a preferred embodiment of the present invention, will be described with reference to FIGS. 1 to 52.

First, a schematic structure of a boiling water reactor to which the method for carrying out nuclear fuel material in the nuclear power plant of this embodiment is applied will be described with reference to FIG. The boiling water reactor includes a reactor 1 and a reactor containment vessel (hereinafter referred to as PCV) 9. The PCV 9 is installed in the reactor building 14, and the upper lid 10 is attached to the upper end thereof and sealed. The PCV 9 has a dry well 11 formed inside, and a pressure suppression chamber 12 in which a pressure suppression pool filled with cooling water is formed. One end of the vent passage connected to the dry well 11 is immersed in the cooling water of the pressure suppression pool in the pressure suppression chamber 12.

A shield plug 15 which is a radiation shield divided into a plurality of parts is arranged directly above the upper lid 10, and these shield plugs 15 are installed on the operation floor of the reactor building 14.

The reactor 1 includes a reactor pressure vessel (hereinafter referred to as RPV) 2 to which an upper lid 3 is attached, a core 4 loaded with a plurality of fuel assemblies containing nuclear fuel material, an air-water separator 6, and steam drying. It is equipped with a vessel 7 and the like. The core 4, the steam separator 6 and the steam dryer 7 are arranged in the RPV 2. A core shroud 116 installed in the RPV 2 surrounds the core 4. Each fuel assembly loaded in the core 4 has a lower end supported by a core support plate 5 and an upper end held by an upper grid plate (not shown). The steam separator 6 is arranged above the upper lattice plate located at the upper end of the core 4, and the steam dryer 7 is arranged above the steam separator 6.

A plurality of control rod guide pipes 8A are arranged below the core 4, and a support cylinder 8 including the plurality of control rod guide pipes 8A is formed. Control rods (not shown) that are taken in and out of the fuel assembly in the core 4 to control the reactor output are arranged in each control rod guide pipe 8A. A plurality of control rod drive mechanism housings 39 are attached to the lower mirror of the RPV2. Control rod drive mechanisms (not shown) are installed in the respective control rod drive mechanism housings 39 and are connected to the control rods in the control rod guide pipe 8A.

Air-water separator 6, steam dryer 7, shroud 87 (described later), upper lattice plate, core shroud 116, core support plate 5, support cylinder 8, control rod guide tube 8A, core shroud lower body installed in RPV2 116A is a core structure.

The RPV2 is installed on a tubular pedestal 37 provided on a concrete mat 38 provided at the bottom of the PCV9. A tubular γ-ray shield 120 is installed at the upper end of the pedestal 37 and surrounds the RPV2.

In such a boiling water reactor, when the reactor is scrummed and the reactor output is reduced, all the power supplies that supply the current of the boiling water reactor are temporarily lost, and the emergency core cooling is performed. It is assumed that a state has occurred in which the system did not operate. If all the power is lost and the pumps of the emergency core cooling system do not operate and the cooling inside each fuel assembly in the core 4 is impaired, the nuclear fuel material contained in the fuel assembly melts and the nuclear fuel material is melted. The molten nuclear fuel material can fall to the bottom of the RPV2.

In the unlikely event that such a molten nuclear fuel material falls to the bottom of the RPV2, the molten nuclear fuel material will be carried out of the RPV2 and the boiling water reactor in which the molten nuclear fuel material has fallen. , Decommissioning is carried out.

In this embodiment, the nuclear fuel material is melted, for example, the nuclear fuel material in a boiling water reactor is carried out of RPV2. The method of carrying out the nuclear fuel material in the nuclear power plant of this embodiment will be described below.

First, obstacles are removed when the nuclear fuel material is carried out (step S1). For example, if there are obstacles on the operating floor of the damaged reactor building when carrying out the nuclear fuel material, these obstacles can be removed by using a crawler crane (not shown) or the like. Will be removed.

A traveling crane is installed above the reactor building (step S2). As shown in FIG. 1, a plurality of support members 29A are installed on the outside of one side wall of each of the opposite side walls of the reactor building 14. A guide rail 31A is installed at the upper end of these support members 29A. A plurality of support members 29B are installed on the outside of the other side wall of each side wall. A guide rail 31B is installed at the upper end of these support members 29B. The facing support members 29A and 29B are connected by a beam 30 placed on the operating floor of the reactor building 14. The gantry traveling crane 32 is installed on the guide rails 31A and 31B using a crawler crane. The traveling crane 32 includes a traveling carriage 33 that moves along the guide rails 31A and 31B, and traversing carriages 34A and 34B that are provided on the traveling carriage 33 and move on the traveling carriage 33 in a direction orthogonal to the guide rails 31A and 31B. Have. Each of the traversing carriages 34A and 34B is provided with hooks 35A and 35B that move up and down by a wire winding device (not shown).

The house is installed on the operating floor of the reactor building (step S3). The work house 16A is suspended from the hooks 35A and 35B of the traveling crane 32, moved onto the operating floor, and installed on the operating floor so as to cover the shield plug 15 (see FIG. 1). The preparation house 16B is suspended from the hooks 35A and 35B of the traveling crane 32, moved above the work house 16A, and installed on the work house 16A (see FIG. 1). In order to maintain the airtightness between the internal spaces 17A and 17B and the outside, a seal is provided between the driver's floor and the floor of the work house 16A, and between the ceiling of the work house 16A and the floor of the preparation house 16B, respectively.

The work house 16A is surrounded by four side walls on all sides, and a floor 22 (see FIG. 2) is attached to the lower end of these side walls, and a ceiling is attached to the upper end of these side walls. Inside the work house 16A, an internal space 17A surrounded by four side walls, a floor and a ceiling is formed. A large opening 23 is formed on the floor 22 of the work house 16A, as shown in FIG. The opening 23 is arranged directly above the shield plug 15, and an opening (not shown) is also formed on the ceiling of the work house 16A directly above the opening 23. The hydraulic pump / control panel 25 is arranged in the internal space 17A and installed on the floor 22. A space 24 on which the carry-out container is placed is secured on the floor 22. The overhead crane 18A is installed near the ceiling in the internal space 17A. The overhead crane 18A has a traveling carriage 19A and a trolley 20A provided on the traveling carriage 19A and movable along the longitudinal direction of the traveling carriage 19A. A hook 21A is hung from the trolley 20A. A ventilation and air conditioning system 36A is provided in the work house 16A, and a plurality of cameras 27A and a dosimeter 28A are installed in the internal space 17A of the work house 16A. A mobile multi-axis robot 26A equipped with a camera for observation is placed on the floor of the work house 16A.

The preparation house 16B is also surrounded by four side walls on all sides, and a floor is attached to the lower ends of these side walls and a ceiling is attached to the upper ends of these side walls. Inside the preparation house 16B, an internal space 17B surrounded by four side walls, a floor and a ceiling is formed. The floor and ceiling of the preparation house 16B also have openings (not shown) directly above the openings 23. This opening does not have to be located directly above the opening 23. Although not shown, the hydraulic pump / control panel 25 is arranged in the internal space 17B and installed on the floor of the preparation house 16B. The overhead crane 18B is installed near the ceiling in the internal space 17B. The overhead crane 18B has a traveling carriage 19B and a trolley 20B provided on the traveling carriage 19B and movable along the longitudinal direction of the traveling carriage 19B. A hook 21B is hung from the trolley 20B. The ventilation and air conditioning system 36B is provided in the preparation house 16B, and a plurality of cameras 27B and a dosimeter 28B are installed in the internal space 17B of the preparation house 16B. A mobile multi-axis robot 26B equipped with a camera for observation is placed on the floor of the preparation house 16B.

After the work houses 16A and 16B are installed, an external power source is connected to the hydraulic pump / control panel 25 in each house. Devices and appliances such as an overhead crane 18A, a ventilation air conditioning system 36A, a camera 27A, and a dose meter 28A provided in the work house 16A are operated by being supplied with electricity from a hydraulic pump / control panel 25 in the work house 16A. Devices and appliances such as an overhead crane 18B, a ventilation air conditioning system 36B, a camera 27B, and a dose meter 28B provided in the work house 16B are operated by being supplied with electricity from a hydraulic pump / control panel 25 in the work house 16B.

The hydraulic pumps / control panel 25 hydraulic pumps installed in the work houses 16A and 16B operate the arms provided on the arms of the mobile multi-axis robots 26A and 26B placed in the work houses 16A and 16B, respectively. Cylinders for use, and mobile multi-axis robots 26A and 26B, cutting and dismantling devices 88, which are connected to each cylinder provided in the cutting and dismantling device 88 and the dismantling grapple device 93 shown in FIG. And control each operation of the dismantling grapple device 93.

The opening / closing door 78 is slidably installed on the upper surface of the ceiling of the preparation house 16B, and opens and closes the opening formed in the ceiling. An opening / closing door 77 (see FIG. 23) is slidably installed on the upper surface of the floor of the preparation house 16B to open / close the opening formed in the floor. The opening / closing operation of the opening / closing doors 77 and 78 is performed by a motor (not shown).

The boring device is carried into the work house (step S4). The boring device 43 is suspended from the hook 35A of the traveling crane 32 (see FIG. 3), and the internal space of the work house 16A is passed through the ceiling and floor of the preparation house 16B and each opening formed in the floor of the work house 16A. It is carried into 17A and placed on the opening / closing shielding member 15A (see FIGS. 3 and 4). At this time, the opening / closing doors 78 and 77 are open. The plug 41 is also suspended from the hook 35A of the traveling crane 32 and carried into the internal space 17A of the work house 16A.

The structure of the opening / closing type shielding member 15A will be described with reference to FIG. The opening / closing type shielding member 15A is arranged below the opening 23 and above the shield plug 15 and has a pair of shielding doors 40A and 40B made of a radiation shielding material. The shielding doors 40A and 40B are movably installed along the rails provided on the pair of beams 30 placed on the driver's floor. The shielding doors 40A and 40B are opened and closed by a motor. The shielding doors 40A and 40B are closed. The plug 41 is installed in the hole 42 formed at the joint of the shielding doors 40A and 40B. After the boring device 43 and the plug 41 are brought into the work house 16A, the opening / closing doors 78 and 77 are closed when the hook 35A is pulled up above the preparation house 16B.

Boring is performed (step S5). The mobile multi-axis robot 26A connects the connector of the power cable 141 connected to the hydraulic pump / control panel 25 in the work house 16A to the boring device 43 in the work house 16A (see FIG. 5). When the boring device 43 is carried out from the work house 16A, the mobile multi-axis robot 26A removes the connector of the power cable 141 from the boring device 43. The description of the work of connecting and disconnecting the power cable 141 and the boring device 43 (or the boring device 43A described later) will be omitted below. After the power cable 141 is connected to the boring device 43, the boring process on the top lid 10 of the PCV 9 and the top lid 3 of the RPV 2 is performed using the boring device 43.

Before explaining these boring processes, the structure of the boring device 43 will be described with reference to FIGS. 6, 7, 9, 10, and 11.

The boring device 43 includes a cutting device 44, a support stand 51, clamp devices 52, 54B, and an extension pipe supply device 60. The support stand 51 has a base 51A and a mast member 51B that is attached to the base 51A and extends upward. A clamp device 52 having an inner blade shaft clamp 52A and an outer blade shaft clamp 52B is fixed to the lower end portion of the mast member 51B. The inner blade shaft clamp 52A is arranged above the outer blade shaft clamp 52B. The moving table 53A is attached to the mast member 51B so as to be movable in the vertical direction. The support member 54 is attached to the moving table 53A. The motors 56A and 56B are attached to the upper surface of the support member 54. The drive socket 54A is connected to the rotating shaft of the motor 56A via a gear mechanism (not shown).

As shown in FIG. 8, the moving table 53B is arranged below the support member 54 and is movably attached to the moving table 53A in the vertical direction. The connector portion 57 provided with the rotating shaft 57A inside is fixed to the moving table 53B. The rotating shaft 57A penetrates the upper end portion of the connector portion 57, and the penetrating portion of the connector portion 57 is sealed to maintain airtightness. A cylindrical clamp device 54B is rotatably attached to the moving table 53B through the moving table 53B. A gear 57C rotatably attached to the moving table 53B meshes with the outer surface of the clamp device 54B. A seal is also provided between the clamp device 54B and the moving table 53B. The cutting device 44 is detachably attached to the clamp device 54B and is gripped by the clamp device 54B. Specifically, the clamp device 54B grips the outer cylinder 45 (described later) of the cutting device 44.

As shown in FIG. 9A, the cutting device 44 has an outer cylinder (outer blade shaft) 45, an outer blade 46, an inner blade 47, and a rotating shaft (inner blade shaft) 48. The rotating shaft 48 is arranged in the outer cylinder 45. A plurality of inner blades 47 are arranged in an annular shape and attached to the lower end of the rotating shaft 48. The plurality of outer blades 46 surround the plurality of inner blades 47 attached to the lower ends of the rotating shaft 48, and are attached to the lower ends of the outer cylinder 45. As shown in FIG. 9A, the width of the outer cylinder 45 of the outer cylinder 45 in the radial direction is larger than the wall thickness of the outer cylinder 45. Two elongated support plates 48A extend from the rotation shaft 48 on the opposite side of 180, and each support plate 48A is rotatably attached to the outer surface of the rotation shaft 48 in the vertical direction. A stopper member (not shown) that prevents the support plate 48A from rotating above the horizontal is fixed to the rotating shaft 48 immediately above the respective mounting positions of the support plate 48A with the rotating shaft 48. The ring member 45A is fixed to the inner surface of the outer cylinder 45 and projects from the inner surface of the outer cylinder 45 toward the rotation shaft 48. The inner diameter of the ring member 45A is larger than the outer diameter of the inner blade 47, and the length of the support plate 48A in the radial direction of the outer cylinder 45 is longer than 1/2 of the inner diameter of the ring member 45A. .. Further, each support plate 48A has a weak spring force sufficient to support its own weight of the support plate 48A, and is pressed against the lower surface of the corresponding stopper member by each spring member (not shown) attached to the rotating shaft 48. There is. Therefore, when the inner blade 47 is inserted into the outer cylinder 45 from the upper end of the outer cylinder 45 to hold the rotating shaft 48 in the outer cylinder 45, the inner blade 47 passes through the ring member 45A and is more than the ring member 45A. Reaching downward, the tip of the support plate 48A is supported on the upper surface of the ring member 45A. Since each support plate 48A does not rotate upward from the horizontal due to the stopper member, each support plate 48A is supported by the ring member 45A, and as a result, the rotating shaft 48 is supported by the outer cylinder 45. An annular passage 50 through which the recovered material (for example, cutting chips) passes is formed between the rotating shaft 48 and the outer cylinder 45.

The rotating shaft 48 is longer than the outer cylinder 45 by the dimension L, and the upper end portion of the rotating shaft 45 projects upward by the dimension L from the upper end of the outer cylinder 45.

As shown in FIG. 8, the rotating shaft 57A is connected to the drive socket 54A with the upper end thereof inserted into the drive socket 54A. The upper end of the outer cylinder 45 is inserted into the clamp device 54B and gripped by the clamp device 54B. The clamp device 54B is a drive socket for rotating the outer cylinder 45. The gear 57C that rotates the clamp device 54B is connected to the rotation shaft of the motor 56B and meshes with a rotational force transmission mechanism (not shown) provided on the support member 54. This rotational force transmission mechanism can disengage the mesh with the gear 57C when the moving table 53B is moved along the moving table 53A.

When the upper end of the outer cylinder 45 is gripped by the clamp device 54B, the upper end of the rotating shaft 48 of the cutting device 44 is connected to the lower end of the rotating shaft 57A.

The recovered material discharge port 58 is provided in the connector portion 57 and is connected to the annular passage 57B formed between the connector portion 57 and the rotating shaft 57A (see FIG. 8). The annular passage 57B is connected to the annular passage 50 in the cutting device 44. A flexible transfer duct 59 connected to the recovered material discharge port 58 is connected to a recovery container (not shown) placed on the base 51A.

The extension pipe supply device 60 includes an extension pipe support member 61 and an extension pipe moving device 63. The extension pipe support member 61 has an extension pipe holding portion 62 at the upper end portion (see FIG. 6). A plurality of extension pipe suspension portions 64 are provided in the extension pipe holding portion 62. As shown in FIG. 11, each extension pipe suspension portion 64 has chuck holders 64A and 64B. The chuck holders 64A and 64B can be moved in the vertical direction separately. With the plurality of extension pipes 66 suspended from the extension pipe holding portion 62, the upper end of the rotation shaft (inner blade shaft) 48 of the extension pipe 66 is gripped by the chuck holder 64A, and the outer cylinder (outer) of the extension pipe 66 is held. The upper end of the blade shaft) 66A is gripped by the chuck holder 64B.

As shown in FIG. 9B, the extension pipe 66 is provided with a rotating shaft (inner blade shaft) 48 in the outer cylinder 66A (outer blade shaft). Similar to the cutting device 44, the extension pipe 66 also has two elongated support plates 48A rotatably attached to the rotating shaft 48 in the vertical direction. Further, a stopper member (not shown) that prevents the support plate 48A from rotating above the horizontal is fixed to the rotating shaft 48, and the ring member 66C is the inner surface of the outer cylinder 45 as in the ring member 45A. It is fixed to. The inner diameter of the ring member 66C is larger than the outer diameter of the inner blade 47. In the extension pipe 66 as well, as in the cutting device 44, each support plate 48A is pressed against the lower surface of the corresponding stopper member by each spring member (not shown) attached to the rotating shaft. Therefore, the rotating shaft 48 of the extension pipe 66 is supported by the outer cylinder 66A by the support plate 48A and the ring member 66C, and the annular passage 50A through which the recovered material (for example, cutting chips) passes between the rotating shaft 48 and the outer cylinder 66A. Is formed. In the extension pipe 66, the lower end of the rotating shaft 48 is located above the lower end of the outer cylinder 66A by the dimension L, and the upper end of the rotating shaft 48 protrudes above the upper end of the outer cylinder 66A by the dimension L.

The extension tube moving device 63 has a rotating body 63A, an arm 65C, and a grip portion 65 (see FIG. 7). The rotary shaft 62A is rotatably attached to the extension pipe holding portion 62 and extends downward from the extension pipe holding portion 62. The rotating body 63A is attached to the rotating shaft 62A. The arm 65C is attached to the rotating body 63A, and the grip portion 65 is provided at the tip end portion of the arm 65C. By turning the rotating body 63A in the horizontal direction, the arm 65C also turns in the horizontal direction. The grip portion 65 has arm clamps 65A and 65B provided at the tip end portion of the arm 65C (see FIG. 11). The arm clamp 65A is located above the arm clamp 65B.

The boring process of the upper lids 10 and 3 will be described. The boring device 43 is mounted on the shielding door 40B of the closed shielding doors 40A and 40B, and the outer blade 46 and the inner blade 47 of the cutting device 44 are formed in the shielding door 40B in one hole 42. It is located directly above. The moving table 53A is lowered to insert the outer blade 46 and the inner blade 47 into the hole 42. When the motor 56A rotates, the drive socket 54A is rotated, the rotating shafts 57A and 48 connected to the drive socket 54A are rotated, and the inner blade 47 is rotated. When the motor 56B rotates, the gear 57C and the clamp device 54B, which is a drive socket, are rotated, the outer cylinder 45 connected to the clamp device 54B is rotated, and the outer cylinder 46 is rotated. With the inner blade 47 and the outer blade 46 rotated, the moving table 53A is gradually lowered along the mast member 51B. The shield plug 15 is gradually cut by the rotation of the inner blade 47 and the outer blade 46, and eventually a through hole is formed in the shield plug 15. The cut piece (a type of recovered material) of the shield plug 15 is driven by a suction device (not shown) provided in the transfer duct 59, and passes through the annular passages 50 and 57B, the recovered material discharge port 58, and the transfer duct 59. It is collected in the collection container. When the outer cylinder 45 is rotating, the clamp device 52 (specifically, the outer blade shaft clamp 52B) does not grip the outer cylinder 45.

When the shield plug 15 is cut by the cutting device 44 that rotates while lowering the moving table 53A and the clamping device 54B is lowered to the position of the clamping device 52 (see FIG. 12A), the lowering of the moving table 53A is stopped. The rotation of the motors 56A and 56B is stopped. Then, the upper end portion of the outer cylinder 45 is gripped by the outer blade shaft clamp 52B. When the clamp device 54B is lowered to the position of the clamp device 52, the inner blade shaft clamp 52A and the outer blade shaft clamp 52B are arranged around the clamp device 54B without contacting the moving base 53B and the clamp device 54B. .. The transfer duct 59, which has flexibility and is connected to the recovered material discharge port 58, also descends as the moving table 53A descends.

Next, the clamp device 54B holding the outer cylinder 45 was opened, and the moving table 53B was turned upward so that the upper end of the rotating shaft 48 of the cutting device 44 was exposed while maintaining the position of the moving table 53A. And move it by a predetermined size. The inner blade shaft clamp 52A grips the upper end portion of the rotating shaft 48 which is connected to the rotating shaft 57A and exposed (see FIG. 12B).

The moving table 53A is raised along the mast member 51B so that the clamp device 54B is above the extension pipe suspension portion 64 provided in the extension pipe holding portion 62. Since the rotation shaft 57A is pulled up by the movement of the movement table 53A, the rotation shaft 57A is separated from the rotation shaft 48. The grip portion 65 grips one extension pipe 66 suspended from the extension pipe suspension portion 64. At this time, the upper end of the rotating shaft 48 of the extension pipe 66 is gripped by the arm clamp 65A, and the upper end of the outer cylinder 66A is gripped by the arm clamp 65B (see FIG. 12C).

The rotating shaft 62A is rotated to rotate the rotating body 63A. The arm 65C rotates in the horizontal direction, and the extension pipe 66 gripped by the arm clamps 65A and 65B is moved to a position directly above the cutting device 44 gripped by the clamp device 52 (see FIG. 12D). Then, the moving table 53A is lowered, and the upper end portion of the rotating shaft 48 of the extension pipe 66 is connected to the lower end portion of the rotating shaft 57A. After connecting the rotary shaft 48 to the rotary shaft 57A, the arm clamp 65A is separated from the upper end of the rotary shaft 48 of the extension pipe 66.

The moving table 53B is moved downward, the upper end portion of the outer cylinder 66A of the extension pipe 66 is inserted into the clamp device 54B, and the upper end portion is gripped by the clamp device 54B (see FIG. 13A). At this time, the rotating shaft 48 of the extension pipe 66 is connected to the rotating shaft 57A. After gripping the outer cylinder 66A with the clamp device 54B, the arm clamp 65B is separated from the upper end portion of the outer cylinder 66A.

The moving table 53B is moved upward on the moving table 53A without moving the moving table 53A (see FIG. 13B). As a result, the outer cylinder 66A is lifted upward.
The moving table 53A is moved downward, and the lower end of the rotating shaft 48 of the extension pipe 66 is connected to the upper end of the rotating shaft 48 of the cutting device 44, which is gripped by the inner blade shaft clamp 52A (FIG. 13). (C)). The lower end of the rotary shaft 48 of the extension pipe 66 and the upper end of the rotary shaft 48 of the cutting device 44 are connected by a known detachable connection structure. After connecting the two rotating shafts 48, the inner blade shaft clamp 52A is separated from the upper end of the rotating shaft 48 of the cutting device 44.

The moving table 53B is moved downward without moving the moving table 53A, and the lower end of the outer cylinder 66A is connected to the upper end of the outer cylinder 45 gripped by the outer blade shaft clamp 52B. After that, the outer blade shaft clamp 52B is separated from the upper end portion of the outer cylinder 45 (see FIG. 13 (D)).

As described above, the connection of the extension pipe 66 to the cutting device 44 is completed.

The connection between the lower end portion of the outer cylinder 66A and the upper end portion of the outer cylinder 45 will be specifically described with reference to FIG. A plurality of pin-shaped connecting members 45B are provided at the connecting portion at the upper end of the outer cylinder 45 (see FIG. 10A). These connecting portions 45B are provided at equal intervals in the circumferential direction of the outer cylinder 45. Each connecting member 45B is pressed by a spring from the inside to the outside of the outer cylinder 45. The surface of the outer tip of each connecting member 45B is processed into a hemispherical shape. A plurality of through holes 66D having an inner diameter of the same size as the outer diameter of the connecting member 45 are formed in the circumferential direction at the connecting portion at the lower end of the outer cylinder 66A. These through holes 66D are formed in the circumferential direction of the outer cylinder 66A at the same interval as the circumferential interval of the connecting member 45B provided on the outer cylinder 45. A curved surface is formed on the inner surface of the lower end portion of the outer cylinder 66A from the lower end of the outer cylinder 66A toward the through hole 66D.

The outer cylinder 66A moves downward as the movement base 53B is lowered, and the upper end portion of the outer cylinder 45 is inserted into the lower end portion of the outer cylinder 66A. When the curved surface formed on the inner surface of the lower end of the lower outer cylinder 66A comes into contact with the hemispherical outer surface of the connecting member 45B provided on the upper end of the outer cylinder 45, the curved surface is formed as the outer cylinder 66A is lowered. Presses the connecting member 45B toward the inside of the outer cylinder 45, overcomes the pressing force on the outside by the spring, and the connecting member 45B moves toward the inside of the outer cylinder 45. When the through hole 66D is lowered to the position of the connecting member 45B, the connecting member 45B pressed outward by the spring is inserted into the through hole 66D. As a result, as shown in FIG. 10B, each connecting member 45B is inserted into each through hole 66D, and the outer cylinder 45 and the outer cylinder 66A are connected.

After that, while rotating the motors 56A and 56B, the moving table 53A is gradually lowered from the state shown in FIG. 13D, and the cutting of the shield plug 15 by the inner blade 47 and the outer blade 46 is restarted. When the clamp device 54B is lowered to the position of the inner blade shaft clamp 52A again, the additional operation of the extension pipe 66 shown in FIGS. 12 (A) to 12 (D) and 13 (A) to 13 (D) is performed. Is repeated, each of the upper lids 10 and 3 is cut by the inner blade 47 and the outer blade 46, and through holes are formed in each of the upper lids 10 and 3 (see FIG. 5). When the through hole is formed in the upper lid 3, the rotation of the motors 56A and 56B and the lowering of the moving table 53A are stopped.

The inner blade is pulled out to retract the boring device (step S6). In step S5, the outer cylinders 45 and 66A of the cutting device 44 and the extension pipe 66 which are connected by cutting the shield plug 15 and the upper lids 10 and 3 through the shield plug 15 and the upper lids 10 and 3 are shielded. The rotating shaft 48 of the cutting device 44 and the rotating shaft 48 of the extension pipe 66 are pulled out, leaving the plug 15 and the upper lids 10 and 3 penetrating. The drawing operation of these rotating shafts 48 will be described with reference to FIGS. 14 and 16.

It is assumed that the lowered moving table 53A is in the state shown in FIG. 14A when the cutting of the upper lid 3 by the cutting device 44 is completed. In this state, the outer blade shaft clamp 52B grips the upper end of the outer cylinder 66A of the extension pipe 66 located at the uppermost position in the shield plug 15.

The clamp device 54B is separated from the outer cylinder 66A, and the moving table 53B is moved upward without raising the moving table 53A. Due to this movement, the clamp device 54B moves upward while being separated from the outer cylinder 66A (see FIG. 14B). At this time, since the rotating shaft 48 of the extension pipe 66 is connected to the rotating shaft 57A, the rotating shaft 48 also moves upward by the amount of increase of the moving base 53B.

As shown in FIG. 14C, the moving table 53A is raised along the mast member 51B until it is located above the arm 65C. The rotating shaft 48 of the extension pipe 66 is pulled out from the outer cylinder 66A, and the rotating shaft 48 of the cutting device 44 connected to the rotating shaft 48 also rises to reach the inside of the outer cylinder 66A from the inner cylinder 45. As described above, the support plate 48A is installed on each rotating shaft 48 so that it can rotate in the vertical direction, and the length of the outer cylinder of each stopper member attached to each rotating shaft in the radial direction is For example, the length is 1/4 of the inner diameter of the ring members 45A and 66C. Therefore, when the rotating shaft 48 of the extension tube 66 located at the uppermost position in the shield plug 15 is pulled out, when the support plate 45A of the cutting device 44 hits the ring member 66C of the extension tube 66 located at the upper position, it moves downward. Each of the support plates 45A of the cutting device 44 can rotate and easily pass through the ring member 66C, and each stopper member of the cutting device 44 can also easily pass through the ring member 66C. When a plurality of extension pipes 66 are connected to the cutting device 44 in step S5, when the rotation shaft 48 of the extension pipe 66 located at the uppermost position in the shield plug 15 is pulled out, the other extension pipes 66 located below Each support plate 48A provided on the rotating shaft 48 also rotates downward and upward together with each stopper provided on the rotating shaft 48 of the other extension pipe 66, similarly to the support plate 48A of the cutting device 44. It can easily pass through the ring member 66C of the extension pipe 66 located.

Therefore, as described above, the rotating shaft 48 of the extension pipe 66 located at the uppermost position in the shield plug 15 can be pulled out from the outer cylinder 66A, and the rotating shaft 48 of the cutting device 44 can also be pulled out from the outer cylinder 45. .. After raising the moving table 53A to a position above the arm 65C, a plurality of rotating shafts 48 (or in step S5 other than the cutting device 44) project to the cutting device 44 protruding above the upper end of the outer cylinder 66A. When the extension pipe 66 is connected, the upper end of the rotation shaft 48) of the other extension pipe 66 is gripped by the inner blade shaft clamp 52A (see FIG. 14C).

The rotating shaft 48 of the extension pipe 66, which is pulled out from the outer cylinder 66A by raising the moving table 53A, and the rotating shaft 48 of the cutting device 44 (or the rotating shaft 48 of another extension pipe 66) existing in the outer cylinder 66A. Is released from the connected state (see FIG. 14 (D)). After that, the rotary shaft 62A and the arm 65C are rotated to rotate the arm clamp 65A to the position of the pulled-out rotary shaft 48, and the arm clamp 65A grips the upper end portion of the rotary shaft 48. The state of connection between the rotating shaft 48 of the extension pipe 66 pulled out from the outer cylinder 66A and the rotating shaft 48 of the cutting device 44 (or the rotating shaft 48 of another extension pipe 66) existing in the outer cylinder 66A is After being released, the rotating shaft 48 of the cutting device 44 (or other extension pipe 66) existing in the outer cylinder 66A located at the uppermost position in the shield plug 15 is located at the uppermost position by the pair of support plates 48A. It is held by the ring member 66C of the outer cylinder 66A located at. Therefore, the rotating shaft 48 existing in the outer cylinder 66A left in the shield plug 15 or the like is prevented from falling.

The moving table 53A is further raised. As the moving table 53A rises, the rotary shaft 57A rises together with the drive socket 54A, and the connection between the rotary shaft 48 gripped by the arm clamp 65A and the rotary shaft 57A is released (see FIG. 15A).

The rotary shaft 62A is rotated to rotate the arm 65C toward the extension pipe supply device 60, and the upper end portion of the rotary shaft 48 gripped by the inner blade shaft clamp 52A is suspended by the extension pipe holding portion 62. It is moved to the position of the lowering portion 64. The upper end of the rotating shaft 48 is gripped by the chuck holder 64A of the extension pipe hanging portion 64 (see FIG. 15B). The inner blade shaft clamp 52A is separated from the rotating shaft 48.

Rotation in which the moving table 53A is lowered so that the lower end of the rotating shaft 57A protrudes upward from the upper end of the outer cylinder 66A whose upper end is gripped by the outer blade shaft clamp 52B and is gripped by the inner blade shaft clamp 52A. It is connected to the upper end of the shaft 48 (see FIG. 15C). Then, the inner blade shaft clamp 52A is separated from the rotating shaft 48.

When a plurality of extension pipes 66 are sequentially connected to the cutting device 44 in step S5, the rotation shafts shown in FIGS. 14 (A) to 14 (D) and FIGS. 15 (A) to 15 (C). The pulling procedure of 48 is repeated until the rotating shaft 48 of the cutting device 44 is gripped by the chuck holder 64A of the extension pipe suspending portion 64.

As described above, the drawing of all the rotating shafts 48 from the outer cylinder is completed. After that, the boring device 43 located on the opening / closing type shielding member 15A moves on the floor of the work house 16A and is retracted to the corner of the work house 16A.

Observe the inside of the RPV (step S7). As shown in FIG. 16, the pipe 68A connected to the ventilation air conditioning / water injection system 69 is connected to the upper end of the outer cylinder 66A located at the uppermost position in the shield plug 15. The connected outer cylinders 66A and 45 penetrate the shield plug 15 and the upper lids 10 and 3. The lower end of the outer cylinder 45 located at the lowermost part reaches the inside of RPV2. After the gas in the RPV2 is sucked and processed by the ventilation air conditioning / water injection system 69, the camera and the dosimeter 68 are inserted into the RPV2 through the pipe 68A and the outer cylinders 66A and 45 (see FIG. 16), and the inside of the RPV2 is inserted. The video information obtained by photographing and the dosimetry value in RPV2 are output. The output video information and dosimetry values are displayed on a display device (not shown) installed in a safe place outside the work house 16A.

The boring object in the RPV is determined (step S8). Since the steam dryer 7 is shown on the display device, the operator first determines the steam dryer 7 and the steam separator 6 as boring objects, and performs boring processing by the boring device 43 for these. Decide that. Then, the operator inputs a command to execute the boring process to the hydraulic pump / control panel 25 from the control room provided on the ground.

Boring to the core is carried out (step S9). The plug 41 installed in the hole 42 formed at the joint of the shielding doors 40A and 40B is pulled out by the mobile multi-axis robot 26A. A drive command is output from the hydraulic pump / control panel 25 (particularly the control panel 25) to the boring device 43, and the boring device until the inner blade 47 and the outer blade 46 of the boring device 43 are located directly above the holes 42. 43 is moved. Similar to step S5, the motors 56A and 56B are rotated to lower the moving table 53A, and while the extension pipe 66 is added, the inner blade 47 and the outer blade 46 are rotated to rotate the shield plug 15 along the central axis of the RPV2. Boring is performed on the upper lids 10 and 3, the steam dryer 7 and the steam separator 6 (see FIG. 16). When the inner blade 47 and the outer blade 46 reach the lower part of the steam separator 6, the rotation of the motors 56A and 56B and the lowering of the moving table 53A are stopped.

The inner blade is pulled out to retract the boring device (step S10). Similar to step S6, the pulling procedure of the rotating shaft 48 shown in FIGS. 14 (A) to 14 (D) and FIGS. 15 (A) to 15 (C) is repeated, and each rotating shaft 48 and the inner blade are repeated. 47 is pulled out from the outer cylinder 66A located at the uppermost position in the shield plug 15, and then the boring device 43 is retracted in the work house 16A. By pulling out each rotating shaft 48 and inner blade 47, each outer cylinder 66A and outer cylinder 45 connected to each other are centered on the RPV2 from the shield plug 15 between the lower end of the steam separator 6 and the upper end of the core 4. It remains aligned along the axis (see Figure 16).

Observe the inside of the core (step S11). The camera and the dosimeter 68 are inserted through the outer cylinders 66A and the outer cylinders 45 arranged in the steam separator 6 and the steam dryer 7 and the like to the position below the steam separator 6 (FIG. 17). reference). The situation of the core 4 is photographed by the camera and the dosimeter 68, and the dose of the core 4 is measured. The video information obtained by the imaging and the measured dose are displayed on the above-mentioned display device installed outside the work house 16A. Since the display device shows the state in which the core 4 is melted, the operator determines that it is necessary to carry out the molten nuclear fuel material. The plug 41 is installed by the mobile multi-axis robot 26A at the upper end of the outer cylinder 66A located at the uppermost position among the outer cylinders 66A arranged on the central axis of the RPV2, and closes the outer cylinder 66A. Based on the measured dose, the amount of shield injected in the next step S12 is determined.

The shield is injected into the core (step S12). The shield supply device 71 is suspended from the hook 35A of the traveling crane 32, and is carried into the internal space 17B of the preparation house 16B through the opening of the ceiling of the preparation house 16B in which the opening / closing door 78 is opened and opened. After the shield supply device 71 is carried into the internal space 17B, the opening / closing door 78 is closed. The shield supply device 71 is suspended from the hook 21B of the overhead crane 18B in the internal space 17B by the mobile multi-axis robot 26B existing in the internal space 17B. After that, the opening / closing door 77 is opened, and the shield supply device 7 suspended from the hook 21B opens the opening / closing door 77 to open the floor opening of the preparation house 16B and the ceiling opening of the work house 16A. It is carried into the internal space 17A of the work house 16A through. After the shield supply device 71 is carried into the internal space 17B, the opening / closing door 78 is closed. The shield supply device 71 is suspended from the hook 21A of the overhead crane 18A by the mobile multi-axis robot 26A, transported to a predetermined place on the floor of the work house 16A, and installed at that place (see FIG. 18). .. The mobile multi-axis robot 26A removes the plug 41 installed in the outer cylinder 66A arranged on the central axis of the RPV2. The injection pipe 72 connected to the shield supply device 71 is connected to the upper end of the outer cylinder 66A arranged at the uppermost position in the shield plug 15 arranged along the central axis of the RPV 2. Two isolated regions are formed in the shield supply device 71, one region is filled with a small iron ball 70A which is a granular shield, and iron powder 70B which is a powder shield is filled in another region. It is filled.

The iron ball 70A is injected into the core 4 from the shield supply device 71 through the injection pipe 72 and the connected outer cylinders 66A and 45 arranged along the central axis of the RPV2. The injected iron balls 70A are filled between the fuel assemblies remaining in the core 4 and in the region where the nuclear fuel material is melted and the fuel assemblies are melted. When a predetermined amount of iron ball 70A is injected and reaches the upper end of the core 4, the injection of iron ball 70A is stopped, and the iron powder 70B ejects the outer cylinders 66A and 45 from the shield supply device 71. Through, it is injected onto the packed bed of iron balls 70A formed in the core 4 (see FIG. 18). An amount of iron powder 70B corresponding to an iron plate having a thickness of 500 mm is injected. The injection status of the iron ball 70A and the iron powder 70B is photographed by the camera 78, and the radiation dose at the time of injection of the iron ball 70A and the iron powder 70B is measured by the dosimeter 68. The injection status of the shield can be monitored by the image output from the camera 78, the radiation shielding effect of the injected shield can be confirmed based on the measured radiation amount, and the core 4 is based on the radiation shielding effect. Adjust the amount of shield injected into the inward. The camera and dosimeter 78 are protected from the shield being injected.

The outer cylinder is collected and the boring device is carried out (step S13). The pipes 82 and 68 are removed using the mobile multi-axis robot 26A. The boring device 43 is arranged on the outer cylinder 66A arranged on the central axis of the RPV2, and the outer cylinder 66A is sequentially pulled up by the boring device 43 and collected in the extension pipe supply device 60, and finally, the outer cylinder 45 Pull up and collect.

The work of collecting the outer cylinders 45 and 66A will be described with reference to FIGS. 19 and 20. For the sake of clarity, each outer cylinder 66A located at the uppermost position in the seal plug 15 (arranged on the central axis of RPV2 in FIG. 18) from which all the rotating shafts 48 were pulled out in steps S6 and S10. It is assumed that the upper ends of the outer cylinder 66A and the other outer cylinder 66A) arranged at positions away from the central axis of the RPV2 are in the state shown in FIG. 19A. In this state, the outer blade shaft clamp 52B grips the upper end portion of the outer cylinder 66A located at the uppermost position in the shield plug 15 on the central axis of the RPV 2.

The moving table 53A is lowered, and the upper end portion of the outer cylinder 66A protruding above the shield plug 15 is gripped by the clamp device 54B (see FIG. 19B). Separate the outer blade shaft clamp 52B from the outer cylinder 66A.

As shown in FIG. 19C, the moving table 53A is raised along the mast member 51B until it is located above the arm 65C. The outer cylinder 66A gripped by the clamp device 54B is pulled out from the shield plug 15, and the lower end of the outer cylinder 66A reaches above the outer blade shaft clamp 52B. In this state, the outer cylinder 45 connected to the outer cylinder 66A (or, when a plurality of extension pipes 66 are connected to the cutting device 44 in step S10, the other outer cylinder 66A) is outside around the upper end portion. There is a blade shaft clamp 52B. The outer blade shaft clamp 52B grips the upper end of the outer cylinder 45 (or another outer cylinder 66A).

The moving table 53A is further raised while the outer blade shaft clamp 52B grips the upper end of the outer cylinder 45 (or another outer cylinder 66A). The lower end of the outer cylinder 66A gripped by the clamp device 54B and the upper end of the outer cylinder 45 (or another outer cylinder 66A) gripped by the outer blade shaft clamp 52B are released from the connected state, and are gripped by the clamp device 54B. The outer cylinder 66 is separated from the outer cylinder 45 (or another outer cylinder 66A) gripped by the outer blade shaft clamp 52B (see FIG. 19 (D)). After that, the rotating shaft 62A and the arm 65C are rotated to rotate the arm clamp 65B to the position of the pulled out outer cylinder 66A, and the arm clamp 65B grips the upper end portion of the outer cylinder 66A.

Specifically, using FIG. 10B, the outer cylinder 66A gripped by the clamp device 54B and the outer cylinder 45 (or another outer cylinder 66A) gripped by the outer blade shaft clamp 52B are released from the connected state. explain. The connecting member release clamp 52C is arranged above the outer blade shaft clamp 52B and attached to the outer blade shaft clamp 52B. As shown in FIG. 19C, when the outer blade shaft clamp 52B grips the upper end of the outer cylinder 45 (or another outer cylinder 66A), the connecting member release clamp 52C faces each connecting member 45B. When the outer blade shaft clamp 52B comes into contact with the outer surface of the outer cylinder 45 (or another outer cylinder 66A), the hemispherical tip of each connecting member 45B is gripped by the connecting member release clamp 52C by the clamping device 54B. It is pushed into the through hole 66D formed in. In this state, when the moving table 53A is raised as shown in FIG. 19D, the tip portion of each connecting member 45B is hemispherical, so that the outer cylinder 66A that is gripped by the clamp device 54B and rises is raised. Each connecting member 45B is further moved inward. Therefore, the tip of each connecting member 45B comes out from each through hole 66D of the outer cylinder 66A, the outer cylinder 66A gripped by the clamping device 54B is moved upward, and the lower end of the outer cylinder 66A is eventually clamped by the outer blade shaft. It reaches above the upper end of the outer cylinder 45 (or another outer cylinder 66A) gripped by the 52B. In this way, the connection state between the outer cylinder 66A gripped by the clamp device 54B and the outer cylinder 45 (or another outer cylinder 66A) gripped by the outer blade shaft clamp 52B is released.

The clamp device 54B is separated from the outer cylinder 66A to further raise the moving table 53A. As the moving table 53A rises, the clamp device 54B also rises, and the clamp device 54B reaches above the upper end of the outer cylinder 66A gripped by the arm clamp 65B (see FIG. 20A).

The rotating shaft 62A is rotated to rotate the arm 65C toward the extension pipe supply device 60, and the upper end portion of the outer cylinder 66A gripped by the outer blade shaft clamp 52B is suspended by the extension pipe holding portion 62. It is moved to the position of the lowering portion 64. The upper end of the outer cylinder 66A is gripped by the chuck holder 64B of the extension pipe suspension portion 64 (see FIG. 20B). The moving table 53A is lowered, and the clamp device 54B grips the upper end of the outer cylinder 45 (or another outer cylinder 66A) whose upper end is gripped by the outer blade shaft clamp 52B and projects upward from the shield plug 15 ( (See FIG. 20B). Separate the outer blade shaft clamp 52B from the outer cylinder 45 (or another outer cylinder 66A). Then, the inner blade shaft clamp 52A is separated from the outer cylinder 66A suspended by the extension pipe suspension portion 64.

When a plurality of extension pipes 66 are sequentially connected to the cutting device 44 in step S5, the outer cylinders shown in FIGS. 19 (A) to 19 (D) and 20 (A) to 20 (C). The pulling procedure is repeated until the outer cylinder 45 of the cutting device 44 is gripped by the chuck holder 64A of the extension pipe suspension portion 64.

Fitting plugs 79A and 79B (see FIG. 22) having screws formed on the side surfaces are inserted into through holes formed in the upper lids 10 and 3 on the central axis of the RPV2, and screws are inserted into the upper lids 10 and 3, respectively. Can be attached by. The boring device 43 is moved onto the other outer cylinder 66A mounted on the shield plug 15, and the boring device 43 is used to move the above-mentioned FIGS. 19 (A) to 19 (D) and 20 (A) to 20 (A). According to the procedure for pulling out the outer cylinder shown in FIG. 20C, the outer cylinder 66A and the outer cylinder 45 are sequentially pulled up from the shield plug 15 and collected. After that, as described above, the fitting plugs 79A and 79B are inserted into the other through holes formed in the upper lids 10 and 3, respectively, and attached to the upper lids 10 and 3, respectively.

After that, the opening / closing door 77 is opened, the boring device 43 is suspended from the hook 21B of the overhead crane 18B using the mobile multi-axis robot 26A, and the winding device (not shown) provided in the trolley 20B is driven. The boring device 43 is raised into the internal space 17B. The boring device 43 is placed on the floor of the preparation house 16B. The opening / closing door 77 is closed, the opening / closing door 78 is opened, and the boring device 43 in the internal space 17B is suspended from the hook 35A of the traveling crane 32 by using the mobile multi-axis robot 26A. By raising the hook 35A, the boring device 43 is carried out of the preparation house 16B. After carrying out the boring device 43, the opening / closing door 78 is closed.

The shield plug is carried out (step S14). The shielding doors 40A and 40B of the opening / closing type shielding member 15A are opened. Similar to the boring device 43 in step S13, the shield plug 15 is carried out of the preparation house 16B from the work house 16A through the preparation house 16B by using the overhead crane 18B and the traveling crane 32. After the removal of the shield plug 15 is completed, the shielding doors 40A and 40B are closed.

The top lid of the PCV is cut and carried out (step S15). Before cutting the PCV top lid 10, four additional floors 73 and one turntable 75 are installed, as shown in FIG. Each additional floor 73 is provided with a 1/4 circular guide rail 74 on the upper surface thereof, and a 1/4 circular arc cutout portion 73A is formed inside the guide rail 74. Similar to the loading of the shield supply device 71 into the work house 16A in step S12, each additional floor 73 and turntable 75 sequentially opens and closes the opening / closing doors 78 and 77 by using the traveling crane 32 and the overhead crane 18B in sequence. Then, it is carried into the work house 16A via the preparation house 16B. Within the work house 16A, each additional floor 73 is suspended and moved by an overhead crane 20A, and is installed on the floor of the work house 16A so that the guide rail 74 is located on the opening 23 side. When the installation of the four additional floors 73 is completed, the guide rails 74 of the four additional floors 73 are connected to form one circle, which is arranged concentrically with the opening 23. The turntable 75 moved by the overhead crane 20A is movably installed on the guide rail 74 along the guide rail 74.

The cutting operation of the upper lid 10 of the PCV 9 and the carrying out of the cut piece 10A of the cut upper lid 10 will be specifically described with reference to FIGS. 22, 23 and 24.

The storage container 80 (see FIG. 22) containing the cutting device 81 is suspended from the hook 35B of the traveling crane 32, and the opening / closing door 78 is opened and opened. The preparation house is opened through an opening formed in the ceiling of the preparation house 16B. It is carried into the internal space 17B of 16B. After the hook 35B is pulled up, the opening / closing door 78 is closed. After that, the storage container 80 suspended from the overhead crane 18B is carried into the work house 16A in the same manner as the shield supply device 71 in step S12. Using the mobile multi-axis robot 26A, the lid of the storage container 80 is opened and the cutting device 81 in the storage container 80 is suspended from the overhead crane 18A. The cutting device 81 is lifted from the storage container 80 by the overhead crane 18A and placed on the turntable 75 in the work house 16A.

The cutting device 81 has a carriage 82, a telescopic tube 84, an arm 85, and a cutter 86 (see FIG. 23). The mast member 83 is installed on the carriage 82 and extends upward. An expansion / contraction tube 84 that can be expanded and contracted in the axial direction is attached to the mast member 83 and extends downward. A refractable arm 85 is attached to the lower end of the telescopic tube 84, and a cutter 86 is attached to the tip of the arm 85.

An electromagnet 87 is suspended from each hook 21A of the two trolleys 20A provided on the overhead crane 18A. Each hook 21A is lowered to attract each electromagnet 87 to the upper surface of the upper lid 10 of the PCV 9. With the upper lid 10 attracted to each electromagnet 87 suspended from each hook 21A, the telescopic tube 84 and the arm 85 are operated to bring the cutter 86 to the cutting position on the upper surface of the upper lid 10 (see FIG. 23). The cutter 86 is pressed against the cutting position to move the turntable 75 on which the cutting device 81 is mounted along the guide rail 74. By moving the turntable 75, the ceiling portion of the upper lid 10 is cut by the cutter 86.

By driving a take-up device (not shown) provided in each trolley 20A and pulling up each hook 21A, the cut circular cut piece 10A of the upper lid 10 moves to the internal space 17A of the work house 16A. (See FIGS. 22 and 24). An opening 10B is formed in the upper lid 10 from which the cut piece 10A is pulled up. The pulled-up cut piece 10A is housed in a carry-out container 76 placed on the floor of the work house 16A, and each electromagnet 87 is removed from the cut piece 10A. A lid is attached to the unloading container 76 by the mobile multi-axis robot 26A, and the unloading container 76 is suspended from the hook 21A of the overhead crane 18A. The carry-out container 76 is moved to the central axis of the RPV2 and suspended from the hook 21B of the overhead crane 20B. As the hook 21B rises, the carry-out container 76 containing the cut piece 10A is pulled up into the preparation house 16B and placed on the floor of the preparation house 16B. The opening / closing door 77 is closed and the opening / closing door 78 is opened. The carry-out container 76 containing the cut pieces 10A in the preparation house 16B is suspended from the hook 35A of the traveling crane 32 and carried out of the preparation house 16B (see FIG. 22).

The top lid of the RPV is carried out (step S16). If the bolt (not shown) that attaches the upper lid 3 to the RPV 2 cannot be removed, the electromagnet 87 is attracted to the upper surface of the upper lid 3 and the upper lid 3 is removed by using the cutting device 81 as in the case of the upper lid 10 in step S15. After cutting, the circular cut piece of the upper lid 3 is stored in the carry-out container and carried out from the work house 16A through the preparation house 16B to the outside of the preparation house 16B. Although not shown, after carrying out the cut piece of the upper lid 3, the cutting device 81 was housed in the storage container 80 using the overhead crane 18A in the work house 16A, and the cutting device 81 was housed by being sealed with the lid. The storage container 80 is moved by using the overhead crane 18B and the traveling crane 32, and is carried out of the preparation house 16B.

The steam dryer is carried out (step S17). Carrying out the steam dryer 7 will be specifically described with reference to FIGS. 25 and 26. Similar to the loading of the cutting device 81 in step S15, the cutting / dismantling device 88 and the dismantling grapple device 93 are separately stored in the storage container, and each storage container in which the cutting / dismantling device 88 and the dismantling grapple device 93 are separately stored is stored. It is sequentially suspended from the hook 35B and carried into the preparation house 16B, and further suspended from the hook 21B of the overhead crane 18B and carried into the work house 16A.

The cutting and dismantling device 88 is installed on one turntable 75 that moves on the guide rail 74, and the dismantling grapple device 93 is installed on another turntable 75 that moves on the guide rail 74. The other turntable 75 is also carried into the work house 16A in the same manner as the former turntable 75.

Each structure of the cutting and dismantling device 88 and the dismantling grapple device 93 will be described with reference to FIG. The cutting / disassembling device 88 includes a support member 89A, a moving table 90A, a main body 91A, an arm 92A, and a cutter 94A. The support member 89A is installed on one turntable 75 and extends upward. The moving table 90A is attached to the support member 89A so as to be movable in the vertical direction along the support member 89A. The main body 91A is installed on the moving table 90A, and the arm 92A is attached to the main body 89A. The cutter 94A is attached to the tip of the arm 91A.

The dismantling grapple device 93 includes a support member 89B, a moving table 90B, a main body 91B, an arm 92B, and a grapple 94B. The support member 89B is installed on another turntable 75 and extends upward. The moving table 90B is attached to the support member 89B so as to be movable in the vertical direction along the support member 89B. The main body 91B is installed on the moving table 90B, and the arm 92B is attached to the main body 89B. The cutter 94B is attached to the tip of the arm 91B.

Each of the moving tables 90A and 90B is lowered to the lowest position along each of the support members 89A and 89B. The arms 92A and 92B are also extended downward. The steam dryer 7 is cut with the cutter 94A while sandwiching the steam dryer 7 with the grapple 94B. The cut piece 7A of the steam dryer 7 is gripped by the grapple 94C suspended from the trolley 20A of the overhead crane 18A. The grapple 94B is separated from the cutting piece 7A, and the grapple 94C is pulled up to move the cutting piece 7A into the work house 16A. The cut piece 7A is stored in the carry-out container 76A placed on the floor of the work house 16A by moving the trolley 20A (see FIG. 25). In this way, the steam dryer 7 is sequentially cut by using the cutter 94A and the grapple 94B, and the cut piece 7A produced by this cutting is grasped by the grapple 94C and stored in the transport container 76A. After all the cut pieces 7A of the steam dryer 7 are stored in the storage container 76A, the storage container 76A containing the cut pieces 7A is sealed with a lid and an overhead crane as in the case of carrying out the storage container 76 in step S15. It is carried out of the preparation house 16B by 18A, 18B and the traveling crane 32.

The steam separator is carried out (step S18). Similar to the removal of the steam dryer 7 in step S17, the steam separator 6 is cut by using the cutting and dismantling device 88 and the dismantling grapple device 93, and the cut pieces of the steam separator 6 are stored in the transport container. It is carried out of the preparation house 16B. After the delivery of the steam separator 6 is completed, the cutting / dismantling device 88 and the dismantling grapple device 93 are stored in separate storage containers, and are carried out from the preparation house 16B using a traveling crane 32 or the like.

The shroud is carried out (step S19). A shroud 87 with a water supply spurger (not shown) and a core spray header mounted inside is provided at the upper end of the core shroud 116 surrounding the core 4 (see FIG. 27). The cutting device 81A used for cutting the shroud 87 is housed in the storage container 80A, and the storage container 80A holds the traveling crane 32 and the overhead crane 18B in the same manner as the storage container 80 containing the cutting device 81 in step S15. It is carried into the work house 16A by using it. The cutting device 81A taken out from the storage container 80A is suspended from the hook 21A of the overhead crane 18A and lowered into the RPV2. When the cutting device 81A descends to the vicinity of the upper end of the shroud 87, the cutting device 81A is fixed to the inner surface of the RPV2 by using the support device 106 provided therein, similarly to the boring device 43A in step S20. The structure of the support device 106 has the same structure as the support device 106 provided in the bowling device 43A shown in FIG. 29, which will be described later.

The structure of the cutting device 81A will be described with reference to FIG. The cutting device 81A attaches the elastic water jet head 95 to the mast member 83 so as to be movable in the vertical direction. In the abrasive water jet head 95, a support member 96 is provided in an outer cylinder 103A having an outer blade 103B attached to the lower end portion, and a support plate 101 forming a horizontal hole 101A is attached to the lower end of the support member 96, and a nozzle is provided. It has a head 97 to which 98 is attached. The cylinder 97 is attached to the support member 96, and one end of the link 100 is connected to a piston rod (not shown) connected to a piston (not shown) arranged in the cylinder 96. The other end of the link 100 is connected to the head 97 by a pin that is inserted into the horizontal hole 101A and can move along the horizontal hole 101A. The high-pressure water supply hose 102A and the elastic supply hose 102B arranged in the outer cylinder 103A are connected to the head 97. The inner blade 104 is attached to the support member 96 by the support rod. When the piston in the cylinder 99 moves upward, the pin inserted in the horizontal hole 101A moves along the horizontal hole 101A (moves from left to right in FIG. 28), and the head 97 And the nozzle 98 moves to the right. Conversely, when the piston is pushed down, the pin moves from right to left, and the head 97 and nozzle 98 also move in the same direction.

The high-pressure water supplied from the high-pressure water supply hose 102A into the head 97 and the abrasive water supplied from the abrasive supply hose 102B into the head 97 are mixed in the head 97, and the high-pressure water containing the abrasive is injected into the nozzle 98. Is jetted from. The injection port of the nozzle 98 is arranged so as to face the cutting position of the shroud 87. High-pressure water containing abrasives injected from this injection port is ejected toward the shroud 87, and the shroud 87 is cut by the action of the abrasive. Since the turntable provided in the support device 106 turns, the cutting device 81 moves in the circumferential direction of the shroud 87 while injecting high-pressure water containing abrasive from the nozzle 98. In this way, the shroud 87 is cut over the entire circumference.

The cut shroud 87 is grabbed by each grapple 94C suspended from two trolleys 20A provided on the overhead crane 18A and raised into the work house 16A. The shroud head 87 is housed in the carry-out container 76B in the work house 16A. The carry-out container 76B containing the shroud 87 is carried out from the work house 16A to the outside of the preparation house 16B via the preparation house 16B by using the overhead crane 16B and the traveling crane 32.

The boring device is installed in the RPV (step S20). The nuclear fuel material is melted in a part of the plurality of fuel assemblies loaded in the core 4. The boring device 43A is used for transporting the nuclear fuel material in the core 4. Similar to the boring device 43 in step S4, the boring device 43A is carried into the work house 16A by using the traveling crane 32 and placed on the floor of the work house 16A.

The structure of the boring device 43A will be described with reference to FIGS. 29 to 34. In the boring device 43A, the cutting device 44 is replaced with the cutting device 44A (nuclear fuel cutting device), the clamping device 54B is replaced with the clamping device 55, the extension pipe 66 is replaced with the extension pipe 66B, and the movement base 53B is deleted. It has a configuration in which a separation device 113 and a shield supply device 114 are newly provided. Other configurations of the bowling device 43A are substantially the same as the bowling device 43.

The boring device 43A includes a cutting device 44A, a support stand 51, clamp devices 52, 55, and an extension pipe supply device 60. Unlike the boring device 43, the clamp device 52 fixed to the lower end of the mast member 51B is not provided with the inner blade shaft clamp 52A and the outer blade shaft clamp 52B, and has one clamp. The support member 54 provided with the drive socket 54A is installed on the moving table 53 attached to the mast member 51B so as to be movable in the vertical direction. A is attached to the mast member 51B so as to be movable in the vertical direction. The support member 54 is attached to the moving table 53A. The drive socket 54A is connected to the rotating shaft of the motor 56A via a gear mechanism (not shown). A connector portion 57 provided with a rotating shaft 57A inside is attached to the lower surface of the support member 54. The rotating shaft 57A is connected to the drive socket 54A.

The electric collecting cable 25A and the hydraulic collecting cable 25B connected to the hydraulic pump / control panel 25 installed on the floor of the work house 16A are connected to the boring device 43A.

Similar to the clamp device 54B, the cylindrical clamp device 55 is rotatably attached to the non-rotating connector portion 57 and has a function of a drive socket. Similar to the clamp device 54B, the clamp device 55 is connected to the rotation shaft of the motor 56B and meshes with a rotational force transmission mechanism (not shown) provided on the support member 54 and the connector portion 57. The outer cylinder 45 (described later) of the cutting device 44A is detachably and rotatably connected to the lower end of the connector portion 57, and is gripped by the clamp device 55.

As shown in FIG. 32, the cutting device 44A has a configuration in which the cutting device 44 is provided with a spiral screw 105. The screw 105 is arranged in the outer cylinder 45 and attached to the rotating shaft 48, but is not attached to the outer cylinder 45. The screw 105 exists between the lower end of the rotary shaft 48 and the upper end thereof, and is attached to the rotary shaft 48 so as to be wound around the outer surface of the rotary shaft 48. A spiral passage 50A through which the recovered material passes is formed between the rotating shaft 48 and the outer cylinder 45. The upper end portion of the rotating shaft 48 is connected to the lower end portion of the rotating shaft 57A in the connector portion 57. The spiral passage 50A is connected to an annular passage formed in the connector portion 57 and connected to the recovered material discharge port 58.

The extension pipe supply device 60 of the boring device 43A has a configuration in which the extension pipe moving device 63 of the boring device 43A is replaced with the extension pipe moving device 63B. Other configurations of the extension pipe supply device 60 of the boring device 43A are the same as the configuration of the extension pipe supply device 60 of the boring device 43A. The extension tube moving device 63B has a rotating body 63A, an arm 65C, and a grip portion 65D (see FIG. 31). The grip portion 65D does not have the arm clamps 65A and 65B as in the grip portion 65 shown in FIG. 7, but has one clamp. The rotating body 63A is attached to the rotating shaft 62A rotatably attached to the extension tube holding portion 62, the arm 64 is attached to the rotating body 63A, and the grip portion 65D is provided at the tip end portion of the arm 65C.

The extension pipe 66B suspended from each extension pipe suspension portion 64 provided in the extension pipe holding portion 62 of the extension pipe supply device 60 has a configuration in which the extension pipe 66 is provided with a spiral screw 105. Other configurations of the extension tube 66B are the same as those of the extension tube 66. In the extension pipe 66B, the spiral screw 105 is arranged in the outer cylinder 66A and exists between the lower end of the rotary shaft 48 and the upper end thereof, and is wound around the outer surface of the rotary shaft 48, similarly to the cutting device 44A. Is attached to the rotating shaft 48. A spiral passage 50A is also formed in the extension pipe 66B by the screw 105.

A transfer duct 59 that is flexible and communicates with the recovered material discharge port 58 is connected to the separation device 113, and the shield supply device 114 is connected to the separation device 113.

The structure of the support device 106 that supports the bowling device 43A in the RPV2 will be described with reference to FIG. The support device 106 includes a turntable 107, a base 108, a cylinder 109, and a pressing member 111. The four cylinders 109 are arranged at 90 ° intervals in the circumferential direction of the circular base 108 and are attached to the side surfaces of the base 108, respectively. Each cylinder 109 extends from the base 108 in all directions, and a pressing member 111 is attached to the tip of a piston rod 110 connected to a piston (not shown) arranged in each cylinder 109. A turntable 107 arranged above the base 108 is rotatably attached to the base 108. The turntable 107 is turned by a motor (not shown) provided on the base 108.

The two guide rails 112 extend in parallel with each other in the radial direction of the RPV 2 and are installed on the upper surface of the turntable 107. The slide base 51C is movably attached to each guide rail 112. The support stand 51 and the extension pipe supply device 60 of the boring device 43A are installed on the upper surface of the slide base 51C. The shield supply device 114 is installed on the upper surface of the turntable 107 as the separation device 113. Between the two guide rails 112, the turntable 107 is formed with an elongated through hole 115 into which the cutting device 44A of the boring device 43A and the extension pipe 66B are inserted. The through hole 115 extends in the radial direction from the center of the turntable 107. Although not shown, the base 108 is also formed with an elongated through hole into which the cutting device 44A and the extension pipe 66B are inserted, facing the through hole 115 formed in the turntable 107. This elongated through hole formed in the base 108 reaches the center of the base 108.

The installation work of the boring device 43A using the support device 106 in the RPV2 will be described. When the boring device 43A is placed on the floor of the work house 16A, a mobile multi-axis robot 26A is used to move four winches 113A and four pulleys 114A around the central axis of the RPV2 in the work house. It is installed on the upper surface of the floor of 16A. The four winches 113A and the pulley 114A are arranged at 90 ° intervals in the circumferential direction of the RPV2. The wire 115A wound around each winch 113A is attached to the suspension ring 107A attached to the base 108 by the mobile multi-axis robot 26A. In the suspension ring 107A, the wires 115A are attached at four positions at 90 ° intervals in the circumferential direction of the suspension ring 107A. The suspension ring 107A surrounds the turntable 107, and the suspension ring 107A and the turntable 107 are separated from each other.

With the four wires 115A attached to the suspension ring 107A and the boring device 43A mounted on the support device 106, the boring device 43A is suspended from the hook 21A of the overhead crane 18A, and the boring device 43A and the support device 106 are attached. Move to the level of the cab just above RPV2. After that, the hook 21A is removed from the boring device 43A, each winch 113A is driven to rewind the wire 115A, and the boring device 43A and the support device 106 are lowered in the RPV2. When the support device 106 reaches the vicinity of the upper end of the core 4, the lowering of the hook 21A is stopped. Flood control is applied to the four cylinders 109 to move the pistons in each cylinder 109 toward the inner surface of the RPV2. Therefore, each piston rod 110 is also moved toward the inner surface of the RPV2, the respective pressing members 111 are brought into contact with the inner surface of the RPV2, and the respective pressing members 111 are pressed against the inner surface of the RPV2. When the pressing member 111 is pressed against the inner surface of the RPV 2 at a predetermined pressure, the supply of oil into each cylinder 109 is stopped. Each pressing member 111 is pressed against the inner surface of the RPV 2 in all directions. In this way, the boring device 43A is installed in the RPV2.

The nuclear fuel material in the core is carried out (step S21). The export of the nuclear fuel material will be described with reference to FIGS. 29 to 36. A boring device 43A is used to carry out the nuclear fuel material. The support member 54 is lowered along the support stand 51, and the lower end of the cutting device 44A is inserted into the through hole 115. The radial position of the RPV2 of the cutting device 44A is adjusted by moving the slide base 51C along the guide rail 112 in the radial direction of the RPV2. When the nuclear fuel material is carried out from the peripheral part of the core 4, the cutting device 44A is located in the peripheral part of the core 4, and when the nuclear fuel material is carried out from the central part of the core 4, the cutting device 44A is placed in the central part of the core 4. To be located in.

When the lower end portion of the cutting device 44A, that is, the outer blade 46 and the inner blade 47 reaches the upper surface of the layer of the iron powder 70B filled in the core 4, in the boring device 43A as in the boring device 43 in step S5. The motors 56A and 56B are rotated to rotate the rotating shaft 48 and the outer cylinder 45, respectively. With the outer blade 46 and the inner blade 47 swiveled, the support member 54 is further lowered, and the swiveled outer blade 46 and the inner blade 47 are lowered from the layer of the iron powder 70B to the region filled with the nuclear fuel material. Let me.

The iron powder 70B and iron ball 70A existing in the core 4, the nuclear fuel material cut by the outer blade 46 and the inner blade 47, and the cutting chips of the metal members constituting the fuel assembly are spirally formed in the outer cylinder 45. Enter the passage 50A. The spiral screw 105 rotating together with the rotating shaft 48 exerts the function of a screw feeder, and removes iron powder 70B, iron ball 70A, and cutting chips of nuclear fuel material and metal members that have entered the spiral passage 50A. It is transferred toward the upper end of the spiral passage 50A, and further transferred to the separation device 113 through the annular passage in the connector portion 57, the collected material discharge port 58, and the transfer duct 59. The screw 105 constitutes a transfer device for the cut nuclear fuel material and the like. In the separating device 113, the iron powder 70B and the iron ball 70A are separated from the nuclear fuel material and the cutting chips of the metal member by using an electromagnet. Since the iron powder 70B and the iron ball 70A are magnetic materials and the cutting chips of the nuclear fuel material and the metal member are non-magnetic materials, the iron powder 70B and the iron ball 70A are cut into the nuclear fuel material and the metal member by using an electromagnet. It can be easily separated from the waste. The metal member of the fuel assembly is made of a zirconium alloy and is a non-magnetic material. The separated iron powder 70B and iron ball 70A are guided into the shield supply device 114. The nuclear fuel material from which the iron powder 70B and the iron ball 70A have been removed and the cutting chips of the metal member are stored in the fuel cask 115A placed on the turntable 107 on the side of the separating device 113. When the fuel cask 115A is filled with cutting chips, the separation device 113 supplies the cutting chips of the nuclear fuel material and the metal member into the empty fuel cask 115A placed next to the fuel cask 115A.

The fuel cask 115A filled with cutting chips is lifted by the hook 21A of the overhead crane 18A and stored in the carry-out container 76D in the work house 16A. When the fuel cask 115A transferred from the turntable 107 and filled with cutting chips is stored in the carry-out container 76D with a predetermined number of units, the carry-out container 76D is the same as the carry-out of the storage container 76 in step S15. , Sealed with a lid, and carried out of the preparation house 16B by the overhead cranes 18A and 18B and the traveling crane 32.

When the clamping device 55 holding the outer cylinder 45 is lowered to the vicinity of the clamping device 52 by cutting the nuclear fuel material and the metal member of the fuel assembly in the core 4, the moving table 53 is lowered and the motors 56A and 56B are rotated. Is stopped, and the extension pipe 66B is connected to the cutting device 44A of the boring device 43A in the same manner as the connection of the extension pipe 66A to the cutting device 44 of the boring device 43 in step S5.

The work of connecting the extension pipe 66B to the cutting device 44A will be specifically described with reference to FIG. 35.

When the nuclear fuel material and the metal member of the fuel assembly are cut by the cutting device 44A that rotates while lowering the moving table 53 and the clamping device 55 is lowered to the vicinity of the clamping device 52 (see FIG. 35 (A)), the moving table The descent of 53 is stopped, and the rotation of the motors 56A and 56B is stopped. The clamp device 52 grips the outer cylinder 45 of the cutting device 44A, and the clamp device 55 holding the outer cylinder 45 is released. After that, the moving table 53 is raised to a position above the extension pipe supply device 60 (see FIG. 35 (B)). The rotating body 63A is swiveled in a state where one extension pipe 66B suspended from the extension pipe suspension portion 64 is gripped by the grip portion 65D of the extension pipe moving device 63B. The arm 65C turns in the horizontal direction, and the extension pipe 66B gripped by the grip portion 65D is moved to a position directly above the cutting device 44 gripped by the clamp device 52 (see FIG. 35 (C)). The moving table 53 is lowered, and the upper end portion of the extension pipe 66B gripped by the grip portion 65D is gripped by the clamp device 55. The grip portion 65D is separated from the extension tube 66B, and the arm 65C is swiveled back to its original position (see FIG. 35 (D)). At this time, the outer cylinder 66A of the extension pipe 66B is detachably connected to the connector portion 57, the upper end portion of the extension pipe 66B rotating shaft 48 is connected to the lower end portion of the rotating shaft 57A, and is gripped by the clamp device 55. Specifically, the clamp device 55 grips the upper end portion of the outer cylinder 66A of the extension pipe 66B. Further, the moving table 53 is lowered to connect the lower end of the outer cylinder 66A of the extension pipe 66B to the upper end of the outer cylinder 45 held by the clamp device 52, and the lower end of the rotating shaft 48 of the extension pipe 66B is connected to the cutting device 44A. It is connected to the upper end of the rotating shaft 48 (FIG. 35 (E)). The clamp device 52 is released, and the gripping of the outer cylinder 45 by the clamp device 52 is released.

After that, the motors 56A and 56B are rotated, the moving table 53 is gradually lowered from the state shown in FIG. 35 (E), and the nuclear fuel material and the metal member of the fuel assembly in the core 4 by the inner blade 47 and the outer blade 46 are used. Cutting is resumed. When the moving table 53 descends to the vicinity of the clamping device 52, the additional operation of the extension pipe 66B shown in FIGS. 35 (A) to 35 (E) is repeated, and the nuclear fuel material existing at a deeper position in the core 4 is removed. It can be collected in the fuel cask 115A while being cut by the cutting device 44A. When the outer blade 46 and the inner blade 47 of the cutting device 44A reach the lower end of the core 4 while cutting the nuclear fuel material or the like, the lowering of the moving table 53 and the rotation of the motors 56A and 56B are stopped.

After that, while performing the operation from FIG. 35 (E) to FIG. 35 (A), the extension pipes 66B added to the cutting device 44A are separated one by one, and these extension pipes 66B are sequentially inserted into the extension pipe supply device 60. Store in. When the cutting device 44A rises to the upper end of the packed bed of iron 70B, the slide base 51C is slightly moved in the radial direction of the turntable 107, and at a different position from the previous time, the core 4 is used by using the cutting device 44A as described above. The nuclear fuel material inside is cut and recovered in the fuel cask 115A. By repeating such work, all the nuclear fuel materials existing in the core 4 are collected, stored in the fuel cask 115A, and carried out of the preparation house 16B. All shields such as iron balls 70A existing in the core 4 are collected by the shield supply device 114. A part of the iron powder 70B and the iron ball 70A collected by the shield supply device 114 is housed in the shield cask 115B placed on the turntable 107. The shield cask 115B is stored in the carry-out container 76D and carried out of the preparation house 16B in the same manner as the fuel cask 115A.

A shield is injected into the core after the removal of the nuclear fuel material (step S22). After the nuclear fuel material in the core 4 is removed by the boring device 43A, a shield such as iron powder 70B (which may contain iron balls 70A) is removed from the shield supply device 114 installed on the turntable 107. It is injected onto the core support plate 5 in the core 4 (see FIG. 37). When the thickness of the injected shield such as iron powder 70B reaches a predetermined thickness on the core support plate 5, the injection of the shield such as iron powder 70B from the shield supply device 114 into the core 4 is stopped. To. A shield layer 117 such as iron powder 70B is formed on the core support plate 5.

The boring device is carried out (step S23). Flood control is applied to each cylinder 109 of the support device 106 in the opposite direction. As a result, each piston rod 110 moves toward the center of the turntable 107, and each pressing member 111 is separated from the inner surface of the RPV 2. In this state, the four winches 113A are driven to wind the wire 115A. Further, the hook 21A is raised. The boring device 43A and the support device 106 are raised to reach the inside of the work house 16A. Similar to the removal of the boring device 43 in step S13, the boring device 43A is carried out of the preparation house 16B, and the opening / closing door 78 is closed.

The core shroud is carried out (step S24). The cutting device 81A is installed on the inner surface of the RPV2 by using the support device 106 as in step S19. The core shroud 116 is cut over the entire circumference using the cutting device 81A in the same manner as in step S19, above the layer of the shield such as iron powder 70B filled on the core support plate 5. An upper grid plate is attached to the cut core shroud. After cutting the core shroud 116, the cutting device 81A is carried out of the preparation house 16B. After that, the cut core shroud to which the upper grid plate is attached is transferred into the work house 16A and stored in the carry-out container in the work house 16A, similarly to the cut shroud 87 in step S19. This carry-out container containing the cut core shroud is carried out from the work house 16A through the preparation house 16B to the outside of the preparation house 16B by using the overhead crane 16B and the traveling crane 32.

Boring up to the bottom of the furnace is carried out (step S25). The boring device 43 is attached to the support device 106, is carried into the work house 16A in the same manner as in step S20, and is further installed on the inner surface of the RPV 2 by using the support device 106. The axial installation position of the RPV2 of the support device 106 is a position slightly above the upper end of the core shroud 116 remaining at this point.

Similar to step S5, the outer blade 46 and the inner blade 47 of the cutting device 44 are swiveled to lower the moving table 53A, and the control rods constituting the core support plate 5 and the support cylinder 8 existing below the core support plate 5 are formed. The guide pipe 8A is cut (see FIG. 38). When the boring position of the core support plate 5 by the cutting device 44 is located directly above the inner region of the control rod guide pipe 8A, the control rod guide pipe 8A by the outer blade 46 and the inner blade 47 No cutting is done. If necessary, as described above, the extension pipe 66 is added to the upper end of the cutting device 44.

The inner blade is pulled out to retract the boring device (step S26). Similar to step S6, the rotary shaft 48 and the inner blade 47 are pulled out, and the outer cylinder 45 is left below the core support plate 5 (when the extension pipe 66 is used, the outer cylinder 66A is also left). The boring device 43 is retracted to near the inner surface of the RPV2 by moving the slide base 51C.

Observe the bottom of the furnace (step S27). The camera and the dosimeter 68 are inserted into the bottom of the core through the outer cylinder 45 or the like left in the RPV2 through the core support plate 5 (see FIG. 39). With this camera and dosimeter 68, the situation of the bottom of the furnace in RPV2 is photographed, and the dose of the bottom of the furnace is measured. Based on the image information and the radiation amount obtained by the camera and the dosimeter 68 displayed on the above display device, the operator determines the presence or absence of the molten nuclear fuel material that has fallen to the bottom of the furnace. Since the molten nuclear fuel material existing at the bottom of the furnace is shown on the display device, it is necessary to cover the molten nuclear fuel material 13 at the bottom of the furnace with a shield and then carry out the molten nuclear fuel material.

The shield is injected into the bottom of the furnace in the RPV (step S28). The boring device 43 is carried out from the preparation house 16B in the same manner as described above, and the boring device 43A attached to the support device 106 is carried into the work house 16A from the outside. Then, as in step S20, the bowling device 43A is installed on the inner surface of the RPV2 using the support device 106. The shield supply device 114 installed on the turntable 107 of the support device 106 is connected to the outer cylinder 45 (or the outer cylinder 66A) penetrating the core support plate 5. Iron powder, which is a shield in the shield supply device 114, is injected into the bottom of the furnace in RPV2 through its outer cylinders 45 (or outer cylinders 66A and 45). The injected iron powder falls from the core 4 and is deposited on the molten nuclear fuel material 13 existing at the bottom of the reactor in the RPV 2, and a shield layer 118 covering the upper part of the molten nuclear fuel material 13 is formed (FIG. 39). reference).

The shield on the core support plate is recovered (step S29). A shield such as iron powder 70B existing on the core support plate 5 is recovered by using the cutting device 44A of the boring device 43A. The motor 56A is rotated to rotate the rotating shaft 48 and the screw 105, and a shield such as iron powder 70B existing on the core support plate 5 is guided into the spiral passage 50A. Since the screw 105 becomes a screw feeder, the shield is guided into the shield cask 115B via the transfer duct 59 and the separating device 113. At this time, the shield cask 115B is connected to the separating device 113. In this way, the shield such as iron powder 70B existing on the core support plate 5 is collected in the shield cask 115B. As described in step S21, the shield cask 115B is transferred into the work house 16A, stored in the carry-out container, and carried out of the preparation house 16B. After the recovery of the shield such as iron powder 70B existing on the core support plate 5 is completed, the boring device 43A is carried out of the preparation house 16B as described above.

The core shroud is carried out (step S30). The storage container 80B containing the cutting device 81A is carried into the work house 16A by using the traveling crane 32 and the overhead crane 18B in the same manner as in step S19. Then, the cutting device 81A taken out from the storage container 80B is suspended from the overhead crane 16A, lowered in the RPV2, and installed on the inner surface of the RPV2 by the support device 106 near the upper end of the core shroud 116 remaining in the RPV2. Will be done. The core shroud 116 uses the cutting device 81A at a position slightly above the core support plate 5, a position slightly below the core support plate 5, and a position below the support cylinder 8, respectively, as in step S19. It is cut over the entire circumference (see FIG. 40). After cutting the core shroud 116 in this way, the cutting device 81A is carried out of the preparation house 16B. After the above cutting, the portion of the core shroud 116 above the core support plate 5, the core support plate 5 and the support cylinder 8 are sequentially transferred into the work house 16A in the same manner as the cut shroud 87 in step S19. To. In the work house 16A, the core shroud 116 is cut and stored in the carry-out container 76E by using the overhead crane 18A, the core support plate 5 is stored in the carry-out container 76F, and the support cylinder 8 is stored in the carry-out container 76G. (See FIG. 40). These carry-out containers 76E, 76F, and 76G are sequentially carried out of the preparation house 16B by using the overhead cranes 18A and 18B and the traveling crane 32.

The molten nuclear fuel material existing at the bottom of the furnace is carried out (step S31). Similar to step S20, the boring device 43A is carried into the work house 16A and further installed on the inner surface of the RPV 2 using the support device 106. In the boring device 43A, similarly to step S21, the outer cylinder 45 and the rotating shaft 48 of the cutting device 44A are rotated to move the moving table 53 downward while rotating the outer blade 46 and the inner blade 47, and further, the extension pipe. The 66B is connected to the upper end of the cutting device 44A, and the moving table 53 is moved downward while turning the outer blade 46 and the inner blade 47. The molten nuclear fuel material 13 existing at the bottom of the furnace is cut by the swirling outer blade 46 and inner blade 47 (see FIG. 41). The iron powder of the shield layer 118 and the cutting chips of the molten nuclear fuel material 13 that have entered the spiral passage 50A are transferred into the outer cylinder 45 by the rotating screw 105, and further, through the transfer duct 59 to the separating device 113. Be transferred. In the separation device 113, as described above, the cutting chips and the iron powder of the molten nuclear fuel material 13 are separated. The separated iron powder is stored in the shield supply device 114. The cutting chips of the molten nuclear fuel material 13 from which the iron powder has been separated are stored in the fuel cask 115A from the separation device 113. The fuel cask 115A filled with the cutting chips of the molten nuclear fuel material 13 is transferred into the work house 16A and stored in the carry-out container 76D. Similar to the removal of the storage container 76 in step S15, the storage container 76 is sealed with a lid and is carried out of the preparation house 16B by the overhead cranes 18A and 18B and the traveling crane 32. When the lower end of the cutting device 44A reaches the bottom surface of the RPV2, the cutting device 44A is pulled up in the same manner as in step S21. When the lower end of the cutting device 44A reaches the upper end of the shield layer 118, the position of the RPV2 of the cutting device 44A in the radial direction is changed, and the cutting device 44A is lowered again to cut the molten nuclear fuel material 13. By repeating the above, all the iron powder and the molten nuclear fuel material existing at the bottom of the furnace in RPV2 are removed by the cutting device 44A.

A shield is injected into the bottom of the furnace after the removal of the nuclear fuel material (step S32). After the nuclear fuel material at the bottom of the furnace is removed by the boring device 43A, iron powder, which is a shield, is injected into the lower body 116A of the core shroud at the bottom of the furnace from the shield supply device 114 installed on the turntable 107. See FIG. 42). When the thickness of the injected iron powder reaches a predetermined thickness on the bottom surface of the RPV2, the injection of the iron powder from the shield supply device 114 to the bottom of the furnace is stopped. An iron powder shield layer 119 is formed on the bottom surface of the RPV2.

After the injection of the shield in step S32 is completed, the boring device 43A is transferred from the RPV2 into the work house 16A, and further carried out from the preparation house 16B to the outside.

Boring to the bottom of the PCV is performed (step S33). As described above, the bowling device 43 attached to the support device 106 is carried into the RPV2 and installed on the inner surface of the RPV2 using the support device 106. In the same manner as in step S5, the outer blade 46 and the inner blade 47 of the cutting device 44 of the boring device 43 are swiveled to lower the moving table 53A, and the bottom portion (lower mirror) of the RPV 2 and the control rod drive mechanism housing 39 are cut. (See FIG. 43). When the boring position of the bottom of the RPV2 by the cutting device 44 is located directly above the inner region of the control rod drive mechanism housing 39, the control rod drive mechanism housing 39 by the outer blade 46 and the inner blade 47 Is not cut. If necessary, as described above, the extension pipe 66 is added to the upper end of the cutting device 44.

The inner blade is pulled out to retract the boring device (step S34). Similar to step S6, the rotating shaft 48 and the inner blade 47 are pulled out, leaving the core shroud lower body 116A and the outer cylinders 66A and 45 connected below the bottom of the RPV2. The boring device 43 is retracted to near the inner surface of the RPV2 by moving the slide base 51C.

Observe the bottom of the PCV (step S35). The camera and dosimeter 68 are inserted into the bottom of the PCV9 through the outer cylinders 66A, 45 (see FIG. 43). The camera and the dosimeter 68 capture the situation at the bottom of the PCV9 and measure the dose at the bottom of the PCV9. Based on the image information and the radiation amount obtained by the camera and the dosimeter 68 displayed on the above display device, the operator determines the presence or absence of the molten nuclear fuel material that has fallen to the bottom of the PCV9. The image displayed on the display device does not include the image of the molten nuclear fuel material that has fallen to the bottom of the PCV9, but includes the image of the iron powder 121 that is the shield that has fallen through the damaged part of the furnace bottom of the RPV2. Imagine a case. The measured dose is also much lower than the dose in the presence of molten nuclear fuel material. Therefore, the operator determines that there is almost no molten nuclear fuel material at the bottom of the PCV9 and iron powder, which is a fallen shield, is present. Therefore, it is necessary to recover the iron powder existing at the bottom of the PCV9. If the molten nuclear fuel material that has fallen to the bottom of the PCV9 is transferred to the display device, this molten nuclear fuel material must be carried out. In this case, as shown in FIG. 52, the molten nuclear fuel material existing at the bottom of the PCV9 is carried out. If the molten nuclear fuel material and the shield that have fallen to the bottom of the PCV 9 are not present, the operations of steps S36, S37, and S38 described later are performed. Here, the recovery of the iron powder existing at the bottom of the PCV9 will be described.

Before recovering the iron powder present at the bottom of the PCV9, the shield existing at the bottom of the furnace is recovered (step S36). The boring device 43 and the support device 106 used in step S34 are carried out through the work house 16A and the preparation house 16B. Instead of the boring device 43, the boring device 43A attached to the support device 106 is carried into the RPV2 via the preparation house 16B and the work house 16A. The boring device 43A is installed on the inner surface of the RPV2 by using the support device 106. The iron powder (shield) existing at the bottom of the furnace is recovered by using the cutting device 44A of the boring device 43A in the same manner as in step S29. The recovered shield is collected in the shield cask 115B. As described in step S21, the shield cask 115B is transferred into the work house 16A, stored in the carry-out container, and carried out of the preparation house 16B. After that, the boring device 43A is carried out of the preparation house 16B as described above.

The lower body of the core shroud and the bottom of the reactor pressure vessel are carried out (step S37). Carrying out the bottom of the furnace will be described with reference to FIG. The storage container containing the cutting device 81A is carried into the work house 16A by using the traveling crane 32 and the overhead crane 18B in the same manner as in step S19. The cutting device 81A taken out from the storage container is suspended by the overhead crane 16A and lowered in the RPV2, and the support device 106 is used in the vicinity of the upper end of the core shroud lower body 116A existing in the RPV2 as described above. Is installed on the inner surface of the RPV2.

In the vicinity of the welded portion with the bottom of the RPV2, the core shroud lower body 116A is cut over the entire circumference by using the cutting device 81A as in step S19. After cutting the core shroud lower body 116A, the cutting device 81A is lifted by the overhead crane 18A and placed on the floor of the work house 16A. The cut core shroud lower body 116A is transferred into the work house 16A and stored in the carry-out container 76H in the work house 16A, similarly to the cut shroud 87 in step S19.

The cutting device 81A is suspended from the overhead crane 16A again to lower the inside of the RPV2, and is installed near the bottom of the furnace on the inner surface of the RPV2 by using the support device 106 as described above. With the plurality of control rod drive mechanisms 39 attached, the bottom of the RPV2 is cut into smaller blocks using the cutting device 81A inside the mounting portion of the RPV2 to the pedestal 37, as in step S19. And drop it on the bottom of PCV9. A plurality of furnace bottom pieces 2A that have been cut and to which the control rod drive mechanism housing 39 is attached are pulled up into the work house 16A by using a grapple or the like attached to the overhead crane 18A, and into the carry-out container 76I in the work house 16A. It is stored.

The carry-out container 76H containing the cut shroud 87 and the carry-out container 76I containing the furnace bottom piece 2A are prepared from the work house 16A via the preparation house 16B using the overhead cranes 16A and 16B and the traveling crane 32, respectively. It is carried out of the house 16B.

The shield at the bottom of the PCV is collected (step S38). The support device 106 in which the separation device 113 is installed on the turntable 107 is carried into the work house 16A in the same manner as the support device 106 of the boring device 43A in step S20, and further lowered in the RPV2 to the RPV2 at a predetermined position. It is installed on the inner surface of the (see FIG. 45). A suction hose 142 is connected to the separation device 113. When the support device 106 is installed on the inner surface of the RPV2, the lower end of the suction hose 142 reaches into the layer of iron powder 121 present at the bottom of the PCV9.

The suction pump connected to the separation device 113 is driven, and the iron powder 121 existing at the bottom of the PCV 9 is sucked and guided to the separation device 113 through the suction hose 142. In the separating device 113, the iron powder 121 and other substances are separated, the separated iron powder 121 is stored in the shield cask 115B, and the other substances are stored in the fuel cask 115A. The shield cask 115B filled with iron powder 121 is transferred into the work house 16A and stored in the carry-out container 76J. When there is no substance such as iron powder 121 on the bottom of the PCV9, the suction of the substance using the suction hose 142 ends. The fuel cask 115A in which other substances are stored is also transferred into the work house 16A and stored in the carry-out container 76D. The carry-out container 76J containing the shield cask 115B and the fuel cask 115A containing other substances are carried out of the preparation house 16B by using the overhead cranes 18A and 18B and the traveling crane 32. After the suction of the iron powder 121 is completed, the support device 106 is also pulled up into the work house 16A, stored in the storage container, transferred, and carried out of the preparation house 16B.

The RPV is carried out (step S39). Carrying out RPV2 will be described with reference to FIG. The storage container containing the cutting device 81A is carried into the work house 16A by using the traveling crane 32 and the overhead crane 18B in the same manner as in step S19. The cutting device 81A taken out of the storage container is installed on the inner surface of the RPV2 by using the support device 106 as described above, below the cutting position at the uppermost position of the RPV2. Since the RPV2 is large, the RPV2 is cut at 6 points in the axial direction for easy unloading. In order to reduce the time required to carry out the RPV2, the support device 106 is arranged below the cutting position of the RPV2 in each cutting operation.

The cutting portion located at the uppermost position of the RPV2 is cut by the action of the abrasive contained in the high-pressure water ejected from the nozzle 98 of the cutting device 81A supported by the support device 106. As the turntable 107 turns, the RPV2 is cut at the cutting point over the entire circumference in the circumferential direction. With the cutting device 81A placed in the RPV2, the cut RPV2B is transferred into the work house 16A and stored in the carry-out container 76L in the work house 16A in the same manner as the cut shroud 87 in step S19. .. The carry-out container 76L containing the cut RPV2B is carried out of the preparation house 16B in the same manner as each of the above-mentioned carry-out containers.

After releasing the pressing of the RPV2 on the inner surface by the pressing member 11, the cutting device 81A is moved downward by the overhead crane 18A, and is installed on the inner surface of the RPV2 by the support device 106 at a position below the next cutting position. Then, the turntable 107 is swiveled as described above, and the RPV2 is cut using the cutting device 81A. The cut RPV2B is stored in the carry-out container 76L as described above and is carried out of the preparation house 16B. In this way, the RPV2 is cut at each cutting point from above and carried out of the preparation house 16B. The lowermost cutting point is a position slightly above the upper end of the support portion for mounting the RPV2 on the pedestal 37. When cutting the RPV2 at this position, the support device 106 is installed on the inner surface of the pedestal 37.

After the removal of the RPV2 is completed, the cutting device 81A is transferred and carried out of the preparation house 16B as described above.

When the removal of the RPV2 and the cutting device 81A is completed, the inside of the reactor building 14 is in the state shown in FIG. 47.

When each of the above steps S1 to S39 is completed, the method for carrying out the nuclear fuel material in the nuclear power plant of this embodiment is completed.

It is assumed that the above steps S1 to S6 are carried out and the observation in RPV2 in step S7 is carried out. At this time, the state in the RPV 2 is that the melting of the nuclear fuel material in the core 4 melts the in-core structures such as the steam dryer 7 and the air-water separator 6, and the nuclear fuel material and the melt 13A of the in-core structure are released. It is assumed that it has fallen to the bottom of the furnace in RPV2. In step S7, the image displayed on the display device and the measured dose obtained by using the camera and the dosimeter 68 indicate that the inside of the RPV2 is in the above state (see FIG. 48). There is. The operator who sees the information displayed on the display device determines the solidified melt 13A existing at the bottom of the furnace as the boring object (step S8). Then, the operations of steps S40 to 41, S14 to S16, S42, S43, S32 to S37, S44 and S39 shown below are executed in order.

A shield is injected into the bottom of the furnace in the RPV (step S40). Using the boring device 43, the cutting device 44 is lowered while adding the extension pipe 66 in the same manner as in step S5. When the lower end of the cutting device 44 reaches the vicinity of the melt 13A at the bottom of the furnace, the lowering of the cutting device 44 is stopped. Then, using the boring device 43, each rotating shaft 48 is pulled out from each extension pipe 66 inserted into the RPV 2 and the cutting device 44 in the same manner as in step S6. As a result, each outer cylinder 66A and the outer cylinder 45 are left in the RPV2 in a connected state.

Injection of the shield (for example, iron powder 121) into the bottom of the furnace is performed in the same manner as in step S12. As shown in FIG. 49, the injection pipe 72 is connected to the shield supply device 71 which is carried and installed in the work house 16A, and is the most of the outer cylinders 66A and 45 which are further connected. It is connected to the upper end of the outer cylinder 66A arranged above. The iron powder 121 is injected into the RPV2 from the shield supply device 71 through the injection pipes 72 and the outer cylinders 66A and 45 arranged in the RPV2, and covers the melt 13A existing at the bottom of the furnace.

The outer cylinder is collected and the boring device is carried out (step S41). Here, in the same manner as in step S13, the outer cylinders 66A and 45 arranged in the RPV2 are collected, and the boline device 43 is carried out from the preparation house 16B.

After the work in step S41 is completed, the above-mentioned operations in steps S14 to S16 are carried out.

The residual equipment in the RPV is carried out (step S42). After the work in step S16 is completed, the cutting device 81A is stored in the storage container and carried into the work house 16A by using the traveling crane 32 and the overhead crane 18B in the same manner as in step S19. Then, the cutting device 81A taken out from the storage container is suspended by the overhead crane 16A and lowered in the RPV2, and is raised by the support device 106 above the residual equipment (internal structure) 122 remaining in the RPV2. It is installed on the inner surface of the RPV2 (see FIG. 50). The residual equipment 122 is cut using the cutting device 81A, and the cut residual equipment 122 is carried into the work house 16A. The residual equipment 122 is stored in the carry-out container 76M in the work house 16A, and is carried out from the preparation house 16B in the same manner as each of the above-mentioned carry-out containers.

The melt is carried out (step S43). Carrying out the melt 13A will be described with reference to FIG. 51. The melt 13A is carried out in this step in substantially the same manner as the carried out of the molten fuel material existing at the bottom of the furnace in step S31. Similar to step S20, the boring device 43A is carried into the work house 16A and further installed on the inner surface of the RPV 2 using the support device 106. In the boring apparatus 43A, similarly to step S21, the outer cylinder 45 and the rotating shaft 48 are rotated to move the outer blade 46 and the inner blade 47 downward while rotating, and the molten nuclear fuel material and the molten furnace existing at the bottom of the furnace. The melt 13A containing the internal structure is cut. If the length of the cutting device 44A is insufficient, the extension pipe 66B is further added to the upper end of the cutting device 44A to cut the melt 13A by the cutting device 44A, as in step S21. The cutting chips of the melt 13A and the iron powder 121 generated by this cutting enter the outer cylinder 45, are pushed out by the rotating screw 105, and are transferred to the separation device 113 through the transfer duct 59.

The cutting chips of the melt 13A and the iron powder 121 are separated by the separating device 113, and the cutting chips of the separated melt 13A are guided to the fuel cask 115A. Further, the separated iron powder 121 is guided into the shield supply device 114.

Similar to step S21, the position of the cutting device 44A in the radial direction of the RPV2 is changed to cut the melt 13A by the cutting device 44A, and all the melts 13A existing at the bottom of the furnace in the RPV2 are used as a plurality of fuel cask. Collect within 115A. Each fuel cask 115A filled with the cutting chips of the melt 13A is transferred to the work house 16A and stored in the carry-out container 76D. The carry-out container 76D containing the fuel cask 115A is carried out from the preparation house 16B.

After that, the above-mentioned operations of steps S32 to S35 are executed in order. In the work of step S35, the situation at the bottom of the PCV9 is photographed by the camera and the dosimeter 68, and the dose at the bottom of the PCV9 is measured. The information displayed on the display device indicates that the melt 13A has fallen to the bottom of the PCV9. The melt 13A existing at the bottom of the PCV 9 is referred to as a melt 13B to distinguish it from the melt 13A existing at the bottom of the furnace. The operator sees the information reported on the display device and determines that the melt 13B at the bottom of the PCV 9 needs to be recovered. After that, the operations of steps S36 and S37 are performed.

The melt at the bottom of the PCV is carried out (step S44). Similar to step S20, the boring device 43A is carried into the work house 16A and further installed on the inner surface of the RPV2 using the support device 106 (see FIG. 52). Similar to the removal of the molten nuclear fuel material 13 at the bottom of the furnace in step S31, the melt 13B existing at the bottom of the PCV 9 is cut by using the cutting device 44A, and the cutting chips of the iron powder 121 and the melt 13B are rotated. It is transferred by 105 and transferred to the separation device 113 through the transfer duct 59. The cutting chips of the melt 13B separated by the separating device 113 are stored in the fuel cask 115A. Further, the iron powder 121 separated by the separating device 113 is stored in the shield cask 115B. The fuel cask 115A filled with the cutting chips of the melt 13B and the shield cask 115B filled with the iron powder 121 are each transferred to the work house 16A. A plurality of fuel cask 115A is housed in the carry-out container 76D, and a plurality of shield cask 115B are housed in the carry-out container 76J. The carry-out containers 76D and 76J are carried out from the preparation house 16B (see FIG. 52).

After that, the RPV2 in step S39 is carried out.

As a result, each work of the nuclear fuel material of the core and the method of carrying out the nuclear fuel material in the nuclear power plant when the internal structure is in a molten state in RPV2 is completed.

In this embodiment, the cutting device 44A is used to cut the molten nuclear fuel material existing in the RPV2 and discharge the cut molten nuclear fuel material, so that the time required to carry out the cut molten nuclear fuel material is shortened. Can be done. In particular, the outer blade 46 provided at the tip of the outer cylinder 45 and the inner blade 47 provided at the tip of the rotating shaft 48 arranged in the outer cylinder 45 are swiveled to rotate the molten nuclear fuel material in the reactor 1. Since the cut molten nuclear fuel material is transferred using the transfer passage formed between the rotating shaft 48 and the outer cylinder 45, the time required to carry out the cut molten nuclear fuel material is reduced. It can be shortened. Since the screw 105 attached to the rotating shaft 48 is rotated around the rotating shaft 48, the cut molten nuclear fuel material can be easily transferred. In particular, in this embodiment, since the screw 105 is provided on the rotating shaft 48 arranged in the outer cylinder 45 in the cutting device 44A, the cutting debris of the nuclear fuel material can be more easily transferred by the screw 105. ..

In this embodiment, after the boring process by the boring device 43 is completed, the outer cylinder 45 of the cutting device 44 and the outer cylinder 66A of the extension pipe 66 are left in the reactor 1 and the rotating shaft 48 in these outer cylinders is pulled out. Therefore, the granular shield (for example, iron ball 70A) and the powder shield (for example, iron powder 70B) can be easily injected into the reactor 1 by using their outer cylinders as injection pipes.

In the cutting device 44 of the boring device 43, the inner blade 47 is attached to the lower end of the rotating rotating shaft 48, and is attached to the lower end of the rotating outer cylinder 45 that surrounds the rotating shaft 48 to surround the inner blade 47. Since 46 is arranged, in a structure in which the rotating shaft 48 is pulled out from the outer cylinder 45, a hole into which the rotating shaft 48 and the outer cylinder 45 can be inserted is formed by the inner blade 47 and the outer blade 46 to shield plug 15, upper lids 10, 3 and steam. It can be formed in a dryer 7 or the like.

When the outer cylinders 45 and 66A are pulled out together with the rotating shaft 48, a part of the injected granular shield and powder shield is inside the air-water separator 6 and the shroud head in which the steam dryer 7 is installed. It accumulates on the upper surface of the surface and interferes with the injection of the granular shield and the powder shield into the core 4, and it takes a long time to inject a predetermined amount of the granular shield and the powder shield. In this embodiment, since the outer cylinders 45 and 66A are left in the steam separator 6 and the steam dryer 7, all the injected granular shields and powder shields pass through the outer cylinders. , Can be injected directly into the core 4.

In addition, those outer cylinders left in the reactor 1 can be used as a guide tube for inserting a camera and a dosimeter 68 for checking the situation inside the reactor 1 into the reactor 1, and the camera and the dose can be used. A total of 68 can be smoothly inserted into the reactor 1, and the situation inside the reactor 1 can be confirmed in a short time.

Based on the information in the reactor 1 (images in the reactor 1 etc.) obtained by the camera and the dosimeter 68 inserted into the reactor 1 through those outer cylinders, the object to be cut in the reactor is appropriately selected. Can be decided. Therefore, the work process for cutting the object to be cut can be appropriately determined. As a result, it is possible to avoid carrying out extra work and shorten the time required to carry out the molten nuclear fuel material.

In this embodiment, since the granular shield and the powder shield are injected into the core, the granular shield and the powder shield filled in the core 4 with the radiation emitted from the nuclear fuel material and the molten nuclear fuel material 13 in the core 4 are injected. It can be shielded by the body. For example, when the equipment used in this embodiment (for example, the boring device 43A) breaks down in the work house 16A, it is necessary for the worker to enter the work house 16A and inspect the failed equipment to confirm the failure status. There is. In some cases, the failed equipment must be repaired in the workhouse 16A. Since the granular shield and the powder shield injected into the core 4 described above shield the radiation, it is possible to suppress the exposure of the workers working in the work house 16A.

In this embodiment, when cutting the molten nuclear fuel material in the core 4 and the molten nuclear fuel material 13 existing at the bottom of the RPV2, the boring device 43A has a pressing device (cylinder 109, pressing member 111, etc.). Since the support device 106 is used to install the boring device 43A on the inner surface of the RPV2, the boring device 43A can be arranged near the existing area above the existing area of the nuclear fuel material to be cut in the RPV2. Therefore, the number of extension pipes 66 to be added can be reduced. Reducing the number of extension pipes 66 to be added brings about a reduction in the time required for addition of the extension pipe 66 and an increase in the turning torque of the outer blade 46 and the inner blade 47. The shortening of the time required for the addition of the extension pipe 66 directly leads to the reduction of the time required for the cutting work of the molten nuclear fuel material. The increase in the turning torque can improve the cutting efficiency of the molten nuclear fuel material by the outer blade 46 and the inner blade 47, and further shorten the time required for cutting the molten nuclear fuel material.

In particular, when cutting the molten nuclear fuel material in the core 4 in the RPV2, before this cutting, the in-core structures (steam dryer 7, air-water separator 6, etc.) existing in the RPV2 above the core 4 Since the shroud 87) is cut and carried out of the RPV2, the boring device 43A is installed on the inner surface of the RPV2 by using the support device 106 above the core 4 in which the nuclear fuel material to be cut is present and near the core 4. can do. Further, when cutting the molten nuclear fuel material 13 existing at the bottom of the RPV2, other internal structures (core shroud 116, core support plate 5, support cylinder 8 and the like) are cut and carried out of the RPV2. , The boring device 43A can be installed on the inner surface of the RPV2 by using the support device 106 near the core portion where the molten nuclear fuel material 13 to be cut exists.

In this embodiment, the boring device 43 is a first rotating device (motor 56A and drive socket 54A) that rotates the rotating shaft 48 and the cutting device 44 on a moving table 53A movably attached to the mast member 51B in the vertical direction. ) Is provided, and a clamp device 54B, which is a second rotating device for rotating the outer cylinder 45 of the cutting device 44 and is a gripping device for the outer cylinder, is attached to the moving table 53B movably attached to the moving table 53A in the vertical direction. A clamp device 52 having an inner blade shaft clamp 52A and an outer blade shaft clamp 52B is attached to the mast member 51B below the first and second rotating devices, and an extension pipe support member 61 and arm clamps 65A and 65B are provided. Since the extension pipe supply device 60 having the extension pipe moving device 63 is provided, as described above, the extension pipe 66 can be added to the cutting device 44 to form a deeper hole, and the atom of the cutting device 44 can be formed. Each rotating shaft 48 of the extension pipe 66 and the cutting device 44 can be pulled out from the outer cylinder 45 and the outer cylinder 66A of the extension pipe 66 left in the furnace 1, and further, the extension pipe 66 left in the reactor 1 can be pulled out. The outer cylinder 66A and the outer cylinder 45 of the cutting device 44 can be pulled out.

In this embodiment, the boring device 43A is a first rotating device (motor 56A and drive socket 54A) for rotating the rotating shaft 48 and the cutting device 44 on a moving table 53 movably attached to the mast member 51B in the vertical direction. ) Is provided, and the support portion 57 attached to the moving table 53 is provided with a second rotating device for rotating the outer cylinder 45 of the cutting device 44A and a clamping device 55 which is a gripping device for the outer cylinder. A clamp device 52 is attached to the mast member 51B below the two-rotating device, and an extension tube supply device 60 having an extension tube support member 61 and an extension tube moving device 63 provided with a grip portion 65D is provided. As described above, the extension pipe 66B can be easily added to the cutting device 44, and the extension pipe 66B and the cutting device 44 can be easily recovered.

In this embodiment, the work house 16A and the preparation house 16B are installed on the operating floor of the reactor building 14, and the internal structures in the reactor (air-water separator 6, steam dryer 7, core shroud 166, etc.) and RPV2 in RPV2 are installed. The respective cutting chips of the molten nuclear fuel material inside and the shields (iron balls 70A and iron powder 70B) injected into the RPV2 are stored in the carry-out container and externally via the work house 16A and the preparation house 16B. It is being carried out to. For this reason, for example, when the unloading container containing the cutting chips and the shield is transferred from the RPV2 to the work house 16A, the radioactive material existing in the work house 16A from the RPV2 is discharged to the external environment. It can be prevented from being done. This is provided with an opening formed in the ceiling of the work house 16A and the floor of the preparation house 16B, which connects the internal space 17A of the work house 16A and the internal space 17B of the preparation house 16B, on the floor of the preparation house 16B. The opening that can be closed by the opening / closing door 77 and that connects the internal space 17B of the preparation house 16B and the external environment formed on the ceiling of the preparation house 16B is closed by the opening / closing door 78 provided on the ceiling of the preparation house 16B. This is because the ventilation and air conditioning systems 36A and 36B for removing radioactive substances are provided in the work house 16A and the preparation house 16B. These ventilation and air conditioning systems can purify the air inside each of the work house 16A and the preparation house 16B, and can remove radioactive substances contained in the respective air in the internal spaces 17A and 17B.

In this embodiment, iron balls 70A and iron powder 70B are used as shields to be injected into RPV2, but tungsten balls and tungsten powder may be used as shields instead of iron balls 70A and iron powder 70B. Since tungsten is not a magnetic material, when separating cutting chips such as nuclear fuel material by the separator 113, the specific gravity of tungsten is higher than that of the cutting waste of the nuclear fuel material and the structural members of the fuel assembly, instead of using an electromagnet. Since it is very large, this difference in specific gravity can be used to separate the cutting chips of the nuclear fuel material and the structural members of the fuel assembly from the tungsten balls and the tungsten powder.

The method of carrying out the nuclear fuel material in the nuclear power plant of Example 2 applied to the boiling water reactor, which is another embodiment of the present invention, will be described with reference to FIGS. 53 to 56.

In the case where the reactor internal structures such as the air-water separator 6 and the steam dryer 7 in the RPV2 are not melted, the method for carrying out the nuclear fuel material in the nuclear power plant of the present embodiment is the step S4 implemented in the first embodiment. Each work of ~ S13 is performed without installing the traveling crane 32 and without installing the work house 16A and the preparation house 16B on the operating floor of the reactor building 14, and after the work of step S13 is completed, the work of step S2 (running). (Installation of the crane 32) and the work of step S3 (installation of the work house 16A and the preparation house 16B) are performed, and then the operations of steps S13 to S39 performed in the first embodiment are performed in order. Further, in the case where the reactor internal structures such as the air-water separator 6 and the steam dryer 7 in the RPV2 are melted, the method for carrying out the nuclear fuel material in the nuclear power plant of the present embodiment is carried out in the first embodiment. The operations of steps S4 to S8, S40 and S41 are performed without installing the traveling crane 32 above the reactor building 14 and further without installing the work house 16A and the preparation house 16B on the operating floor of the reactor building 14. After the work of step S41 is completed, the work of step S2 (installation of the traveling crane) and the work of step S3 (installation of the work house 16A and the preparation house 16B) are performed, and then steps S14 to S16 and S42 performed in the first embodiment. Each of the operations of ~ S43, S32 to S37, S44 and S39 is performed in order.

The obstacle in step S1 is removed. Obstacles on the operating floor of the reactor building are removed using a crawler crane (not shown).

The boring device is installed on the opening / closing type shielding member 15A provided on the operating floor of the reactor building (step S45). The work of step S45 is the work corresponding to step S4 of the first embodiment. The boring device 43 is suspended by a crawler crane installed on the ground and placed on an openable and closable shielding member 15A provided on the operation floor of the reactor building 14 (see FIG. 53).

Boring is performed (step S46). The work of step S46 is the work corresponding to step S5 of the first embodiment. A mobile multi-axis robot 26A placed on the driver's floor 143 connects the connector of the power cable to the boring device 43 on the driver's floor 143. When the boring device 43 is lowered from the driver's floor 143 to the ground, the mobile multi-axis robot 26A also removes the connector of the power cable from the boring device 43. The description of the connection and disconnection work between the power cable and the boring device 43 (or the boring device 43A described later) will be omitted below. The boring process on the upper lid 10 of the PCV 9 and the upper lid 3 of the RPV 2 is performed using the boring device 43 in the same manner as in step S5 of the first embodiment.

The inner blade is pulled out to retract the boring device (step S47). The work in step S47 corresponds to step S6 in the first embodiment. Of the cutting device 44 and extension pipe 66 arranged so as to penetrate the shield plug 15 and the upper lids 10 and 3, the rotating shafts 48 of the cutting device 44 and the extension pipe 66 are used, and the boring device 43 on the cab 143 is used. In the same manner as in step S6, the outer cylinders 45 and 66A connected to each other are pulled out. These outer cylinders 45 and 66A are left in a state of penetrating the shield plug 15 and the upper lids 10 and 3. The boring device 43 moves on the driver's floor 143 and is retracted to the corner of the driver's floor 143.

Observe the inside of the RPV (step S48). The work of step S48 is the work corresponding to step S7 of the first embodiment. As shown in FIG. 54, the pipe 68A connected to the ventilation air conditioning / water injection system 69 installed on the driver's floor 143 is connected to the upper end of the outer cylinder 66A located at the uppermost position through the shield plug 15. .. A camera and a dosimeter 68 inserted into the RPV2 through the pipe 68A and the outer cylinders 66A and 45 display the video information in the RPV2 and the dosimetry value in the RPV2 in a safe place on the ground (shown). Is output to.

The boring object in the RPV is determined (step S49). Since the image displayed on the display device includes the image of the steam dryer, the operator determines the steam dryer 7 and the steam separator 6 as boring objects. The operator who targets these determines the steam dryer 7 and the steam separator 6 as boring objects, and decides to perform boring processing for these.

Boring to the core is carried out (step S50). The work of step S50 corresponds to step S9 of the first embodiment. Similar to step S9, the boring device 43 lowers the cutting device 44 while adding the extension pipe 66, and the rotation of the inner blade 47 and the outer blade 46 causes the shield plug 15 and the upper lids 10, 3 along the central axis of the RPV 2. , The steam dryer 7 and the steam separator 6 are subjected to boring processing (see FIG. 54).

The inner blade is pulled out to retract the boring device (step S51). The work of step S51 is the work corresponding to step S10 of the first embodiment. Similar to step S6, each rotating shaft 48 and the inner blade 47 are pulled out, and the boring device 43 is retracted on the cab 143. The connected outer cylinders 45 and 66A are arranged from the shield plug 15 between the lower end of the steam separator 6 and the upper end of the core 4 along the central axis of the RPV2 (FIG. 55). reference).

Observe the inside of the core (step S52). The work of step S52 is the work corresponding to step S11 of the first embodiment. An image and a dosimetry value in the core 4 can be obtained by a camera and a dosimeter 68 (see FIG. 55) inserted into the core 4 through the connected outer cylinders 45 and 66A. The operator grasps that the nuclear fuel material in the core 4 is melted based on this image and the dosimetry value.

The shield is injected into the core (step S53). The work in step S53 corresponds to step S12 in the first embodiment. The iron balls 70A and the iron powder 70B are arranged along the central axis of the RPV2 from the shield supply device 71 installed on the driver's floor 143 and connected to each other, respectively 45, 66A, as in step S12. It is injected into the core 4 through the core 4 (see FIG. 56). The iron ball 70A is injected before the iron powder 70B.

After the injection of the iron ball 70A and the iron powder 70B in step S53 is completed, the outer cylinder is collected and the boring device is removed (step S54). The work of step S54 is the work corresponding to step S13 of the first embodiment. The boring device 43 that has collected the outer cylinders 45 and 66A is removed from the operation floor 143 using a crawler crane and lowered to the ground.

After the end of step S54, the work of step S2 (installation of the traveling crane 32) and the work of step S3 (installation of the work house 16A and the preparation house 16B) performed in the first embodiment are performed (see FIG. 56). By these operations, as in the first embodiment, the traveling crane 32 is installed across the reactor building 14, and the work house 16A is installed on the operating floor 143 of the reactor building 14 so as to cover the shield plug 15. Then, the preparation house 16B is installed on the work house 16A. After that, each of the operations of steps S14 to S39 performed in the first embodiment is performed.

The method of carrying out the nuclear fuel material of this embodiment when the in-core structures such as the steam separator 6 and the steam dryer 7 are melted in the RPV2 will be described below.

Each of the operations of steps S45 to S48 is performed, and the video information and the dose measurement value in RPV2 obtained by the camera and the dosimeter 68 in step S48 are the furnaces such as the steam separator 6 and the steam dryer 7 in RPV2. It shows that the internal structure and the nuclear fuel material are melted. Therefore, the operator determines the solidified melt 13A (see FIG. 48) existing at the bottom of the furnace in the RPV2 as the boring object. After that, steps S40 and S41 carried out in the first embodiment further install the work house 16A and the preparation house 16B on the operating floor 143 of the reactor building 14 without installing the traveling crane 32 above the reactor building 14. It is done without.

In the work of step S40 performed in this embodiment, the iron powder 121 is introduced from the shield supply device 71 installed on the driver's floor 143 to the injection pipe 72, and each outer cylinder 45 connected and arranged in the RPV2. This is done by injecting into RPV2 through 66A. The melt 13A present at the bottom of the RPV2 is covered with the injected iron powder 121. In step S41, after the outer cylinders 45 and 66A arranged in the RPV2 are collected by the boring device 43, the boring device 43 is lowered from the operation floor 143 by a crawler crane to the ground.

After the work in step S41 is completed, the work in step S2 (installation of the traveling crane 32) and the work in step S3 (installation of the work house 16A and the preparation house 16B) are performed. The traveling crane 32 is installed so as to straddle the upper part of the reactor building 1, and the work house 16A and the preparation house 16B are installed on the operation floor 143. , S32 to S37, S44 and S39 are executed in order.

In this example, each effect produced in Example 1 can be obtained. Further, in this embodiment, each of the operations of steps S45 to S54, S40 and S41 does not install the traveling crane 32 above the reactor building 14, and further the work house 16A and the preparation house 16B are placed on the operating floor 143 of the reactor building 14. Since it is carried out without being installed in the reactor, the time required for carrying out the nuclear fuel material in the present embodiment can be shortened as compared with the first embodiment. This means that in each of the operations of steps S45 to SS48, S50 to S54, S40 and S41 of this embodiment, the necessary equipment is brought into the work houses 16A and 16B performed in the first embodiment, and the equipment is carried from these houses. This is because it is not necessary to carry it out.

The method of carrying out the nuclear fuel material in the nuclear power plant of Example 3 applied to the boiling water reactor, which is another embodiment of the present invention, will be described with reference to FIGS. 57 to 59.

In the method for carrying out the nuclear fuel material of this embodiment, in Examples 1 and 2, the nuclear fuel material is cut and carried out by using the shield device 123 instead of the boring device 43A. The structure of the shield device 148 will be described with reference to FIG. 57. The shield device 148 includes a shield cutting device 123, a recovery pipe attachment / detachment portion, and a recovery pipe supply device 137.

The shield cutting device 123 has a cutting portion and a propulsion portion. The cutting portion has a rotating body 124 and a plurality of cutters 125, and the plurality of cutters 125 are attached to the front surface of the rotating body 124. The propulsion unit has a tubular body portion 126 and a plurality of propulsion jacks 127. The propulsion jacks 127 are arranged at predetermined intervals in the circumferential direction of the tubular body portion 126, and are attached to the tubular body portion 126. The tubular body portion 126 is attached to the front surface of the housing body portion 123A of the shield cutting device 123. The rotating body 124 is rotatably attached to the front surface of the tubular body 126, and is rotated by a first motor (not shown) installed in the tubular body 126. The recovery pipe 128 is fixed to the housing body 123A. Although not shown, a cutting waste transfer passage is formed inside each of the tubular body portion 126 and the housing body portion 123A, and this cutting waste transfer passage is connected to the above-mentioned recovery pipe 128. A screw feeder (not shown) is installed in this cutting waste transfer passage.

The recovery pipe attachment / detachment portion includes a clamp device 135, a recovery pipe holding member 136, a clamp moving device, and a support frame 131. The support frame 131 has two support members 132A and 132B, a connecting member 133, and a base member 144 in which a penetrating opening 145 is formed. The lower ends of the two support members 132A and 132B are attached to the upper surface of the base member 144 installed on the driver's floor 143, and extend upward while being separated from each other. The upper ends of the support members 132A and 132B are connected by the connecting member 133. The recovery pipe holding member 136 is slidably attached to each of the support members 132A and 132B at the upper ends of the support members 132A and 132B.

The clamp moving device includes a pair of rod-shaped rotating members 134A and 134B, a second motor (not shown), and a rotation transmitting mechanism (not shown). The rotating members 134A and 134B each have screws formed on their outer surfaces. The rotating member 134A is arranged along the supporting member 132A, and the rotating member 134B is arranged along the supporting member 132B. The lower end of the rotating member 134A is rotatably attached to the base member 144, and the upper end of the rotating member 134A is rotatably attached to the connecting member 133. The lower end of the rotating member 134B is rotatably attached to the base member 144, and the upper end of the rotating member 134B is rotatably attached to the connecting member 133. A second motor for rotating the rotating members 134A and 134B is installed at the center of the connecting member 133. A rotation transmission mechanism for transmitting a rotational force from the second motor to the rotating member 134A is attached to the connecting member 133, and a rotation transmitting mechanism for transmitting a rotational force from the second motor to the rotating member 134B is attached to the connecting member 133.

The clamp device 135 has a clamp mechanism 146 and support portions 147A and 147B. The support portions 147A and 147B are attached to the clamp mechanism 146 and face 180 ° in opposite directions. Each of the support portions 147A and 147B has a threaded hole. The rotating member 134A penetrates the screw hole of the support portion 147A, and the screws of the support portion 147A and the rotating member 134A are in mesh with each other. The rotating member 134B penetrates the screw hole of the support portion 147B, and the screws of the support portion 147B and the rotating member 134B are in mesh with each other. The clamp device 135 is thus held by the rotating members 134A, 134B.

The recovery pipe supply device (extension pipe supply device) 137 has a grip portion (not shown) for gripping the recovery pipe (extension pipe) 139, and is rotatably attached to the support member 132B in the horizontal direction.

The method of carrying out the nuclear fuel material of this embodiment will be described below. Each of the operations of steps S1 to S7 performed in the first embodiment is performed in order, and in step S8, it is determined that the boring object (cutting object) in the RPV 2 is the steam dryer 7 and the steam separator 6. Then, each of the operations of steps S9 to S14 is performed in order. After the work in step S14 is completed, the work house 16A and the preparation house 16B installed on the operation floor 143 are removed from the operation floor 143 and transferred to the ground by using the traveling crane 32 (or a crawler crane). ..

Install the shield device (step S55). The traveling crane 32 is used to transport all the parts constituting the shield device 148 onto the cab 143. Then, in the following steps, the shield device 148 is installed on the driver's floor 143. A traveling crane 32 is used to install the shield device 148. The base member 144 is installed on the driver's floor 143 so that the opening is located directly above the RPV2. Other members of the shield device 148 are assembled with reference to the base member 144. The lower ends of the support members 132A and 132B are attached to the base member 144, and the lower ends of the rotating members 134A and 134B are rotatably attached to the base member 144. The clamp device 135 is attached to the rotating members 134A and 134B, and the recovery tube holding member 136 is attached to the supporting members 132A and 132B, respectively. The recovery tube supply device 137 is attached to the support member 132B as described above. The connecting member 133 on which the motor and the rotation transmission mechanism are installed is attached to the upper ends of the support members 132A and 132B, respectively, and the upper ends of the rotating members 134A and 134B are rotatably attached to the connecting member 133.

The recovery pipe 129 to which the nuclear fuel material transfer pipe 130 is connected is connected to the recovery pipe 128. The recovery tube holding member 136 grips the recovery tube 129. The nuclear fuel material transfer pipe 130 is installed from the driver's floor 143 to the nuclear fuel material recovery building (not shown) installed on the ground.

The nuclear fuel material is carried out (step S56). The recovery pipe holding member 136 is lowered to lower the shield cutting device 123, and the cutter 125 of the shield cutting device 123 is brought closer to the upper lid 10 of the PCV 9. The recovery pipe holding member 136 is lowered, for example, by the hydraulic cylinders installed in the holding members 132A and 132B, respectively. The clamp device 135 is also lowered so that the recovery tube holding member 136 does not come into contact with the clamp device 135. When the cutter 125 does not come into contact with the upper surface of the upper lid 10 due to the lowering of the recovery pipe holding member 136, the recovery pipe 139 held by the recovery pipe supply device 137 is connected to the recovery pipe 128 fixed to the housing body 123A. To do.

The connection of the recovery pipe 139 to the recovery pipe 128 is performed as follows. The chuck of the chuck mechanism 146 is expanded to rotate the second motor, and the rotating members 134A and 134B are rotated, respectively. The clamp device 135 is lowered by the rotation of the rotating members 134A and 134B. When the clamp mechanism 146 descends to the position of the recovery pipe 128, the rotation of the rotating members 134A and 134B is stopped, and the descending of the clamp device 135 is stopped. The expanding clamp mechanism 146 is narrowed and the recovery tube 128 is gripped by the clamp mechanism 146. Then, the connection between the recovery tube 128 and the recovery tube 129 is released, and the recovery tube holding member 136 is raised to move the recovery tube 129 upward. When the distance between the recovery pipe 128 and the recovery pipe 129 becomes equal to or greater than the length of the recovery pipe 139, the rise of the recovery pipe holding member 136 is stopped. The recovery pipe supply device 137 that grips the recovery pipe 139 to be connected swivels to position the recovery pipe 139 between the recovery pipe 128 and the recovery pipe 129 directly above the recovery pipe 128. The rotation of the rotating members 134A and 134B raises the clamp device 135 to bring the upper end of the recovery tube 128 into contact with the lower end of the recovery tube 139 gripped by the recovery tube supply device 137. In this state, the recovery pipe 128 and the recovery pipe 139 are connected. The recovery tube holding member 136 is lowered to bring the lower end of the recovery tube 129 into contact with the upper end of the recovery tube 139, and the recovery tube 129 and the recovery tube 139 are connected. At this time, the chuck mechanism 146 is expanded to separate the chuck mechanism 146 from the recovery tube 128.

The recovery pipe holding member 136 is lowered with the recovery pipe 139 connected until the cutter 125 comes into contact with the upper surface of the upper lid 10. If the cutter 125 does not come into contact with the upper surface of the upper lid 10 even if one collection pipe 139 is connected, the required number of pipes can be obtained by the above operation until the cutter 125 comes into contact with the upper surface of the upper lid 10. The recovery pipe 139 is further added. When the cutter 125 comes into contact with the upper surface of the upper lid 10, the lowering of the recovery pipe holding member 136 is stopped.

A plurality of propulsion jacks 127 are driven to move the rotating body 124 toward the front surface in the axial direction of the shield cutting device 123, and the plurality of cutters 125 are pressed against the upper surface of the upper lid 10. The first motor is rotated to rotate the rotating body 124. As a result, the plurality of cutters 125 rotate to cut the upper lid 10. Each propulsion jack 127 is also a guide member, and the outer surface of each propulsion jack 127 facing the inner surface of the RPV2 comes into contact with the inner surface of the RPV2, assisting the movement of the cutting portion and the propulsion portion within the RPV2. The reaction force generated during cutting by the plurality of cutters 125 is received by the recovery pipe holding member 136.

The cutting chips of the upper lid 10 generated by cutting the cutter 125 are collected by the rotation of the screw feeder installed in the cutting waste transfer passage, the cutting waste transfer passage in the shield cutting device 123, and the connected collection pipes 128, 139, It is transferred to the nuclear fuel material recovery building through 129 and the nuclear fuel material transfer pipe 130. The transferred cutting chips are collected in a cutting waste storage tank installed in the nuclear fuel material recovery building. The cutting waste storage tank is surrounded by a radiation shield.

By advancing the rotating body 124 driven by the propulsion jack 127, the upper lid 10 is cut to form an opening 10B penetrating the upper lid 10 (see FIG. 58). The inner diameter of the opening 10B is sized so that the shield cutting device 123 can pass through. When the cutting of the upper lid 10 by the cutter 125 is completed, the driving of the propulsion jack 127 is stopped, and the recovery pipe holding member 136 is lowered by the hydraulic cylinder until the cutter 125 comes into contact with the upper surface of the upper lid 3 of the RPV 2. The propulsion jack 127 is driven again to rotate the rotating body 124, and the upper lid 3 is cut by a plurality of rotating cutters 125. The cutting chips of the upper lid 3 are also transferred to the nuclear fuel material recovery building through the cutting waste transfer passage in the shield cutting device 123, the connected recovery pipes 128, 139, 129 and the nuclear fuel material transfer pipe 130, and air is transferred by the separation device. Is separated from. The separated cutting chips of the upper lid 3 are also collected in the cutting waste storage tank.

When the cutting of the upper lid 3 by the cutter 125 is completed, the drive of the propulsion jack 127 is stopped, and the recovery pipe holding member 136 is lowered by the hydraulic cylinder until the cutter 125 contacts the upper end of the steam dryer 7 in the RPV 2. .. The upper lid 3 that has been cut is also formed with an opening having a size that allows the shield cutting device 123 to pass through. In the middle of the lowering of the recovery tube holding member 136, a new recovery tube 139 is inserted between the recovery tube 129 and the recovery tube 139 directly connected to the recovery tube 129, and these recovery tubes are inserted. It is connected to 129 and 139, respectively.

When the cutter 125 comes into contact with the upper end of the steam dryer 7, the lowering of the recovery pipe holding member 136 is stopped, the propulsion jack 127 is driven, and the rotating body 124 is also rotated. The steam dryer 7 is cut from the upper end to the lower end by the swivel cutter 125. When the rotating body 124 is moved downward by a predetermined distance by driving the propulsion jack 127, the rotating body 124 is moved upward by a predetermined distance by moving the propulsion jack 127 in the opposite direction. After that, the recovery pipe holding member 136 is moved downward by the distance by the hydraulic cylinder and stopped. The propulsion jack 127 is driven again, and the steam dryer 7 is cut by the swirling cutter 125. Such driving of the propulsion jack 127 and lowering of the recovery pipe holding member 136 are repeatedly performed, the steam dryer 7 is cut to the lower end by the cutter 125, and the steam dryer 7 is completely cut. As described above, the cutting chips of the steam dryer 7 are also transferred in the cutting waste transfer passage in the shield cutting device 123, the connected recovery pipes 128, 139, 129 and the nuclear fuel material transfer pipe 130, and store the cutting waste. It is collected in the tank.

The propulsion jack 127 is driven and the recovery pipe holding member 136 is repeatedly lowered, the recovery pipe 139 is repeatedly added as necessary, and the steam separator 6 is cut by the swivel cutter 125 (FIG. FIG. 58). The cutting chips of the steam separator 6 are also collected in the cutting waste storage tank.

Further, the propulsion jack 127 is repeatedly driven and the recovery pipe holding member 136 is repeatedly lowered, and the recovery pipe 139 is repeatedly replenished as necessary. The swirling cutter 125 causes the upper lattice plate and the nuclear fuel in the core 4 to be replenished. Each fuel assembly containing the material, the core shroud 116, the core support plate 5, the support cylinder 8, the plurality of control rod guide pipes 8A, the molten nuclear fuel material 13 that has fallen to the bottom of the RPV2, and the bottom of the RPV2 are sequentially cut. These cutting chips are also transferred to the nuclear fuel material recovery building through the insides of the shield cutting device 123, the recovery pipes 128, 139, 129 and the nuclear fuel material transfer pipe 130, and are collected in the cutting waste storage tank. When cutting the bottom of the RPV2, a plurality of control rod drive mechanism housings 39 attached to the bottom of the RPV2 fall to the bottom of the PCV9, but the shield cutting device 123 is lowered to the vicinity of the bottom of the PCV9, so that the dropped control rods The drive mechanism housing 39 is also cut by the cutter 125.

As a result, all the operations of the method for transporting the nuclear fuel material of this embodiment are completed. The cutting chips collected in the cutting waste storage tank are stored in the fuel cask as needed and transferred to the fuel cask storage building.

When it is determined that the boring object (cutting object) in the RPV2 is the melt 13A existing at the bottom of the RPV2 based on the observation information in the RPV2 in step S7, the shield device 148 in step S55 described above. Is installed on the cab 143, and the melt 13A containing the nuclear fuel material in step S56 is carried out. In this step S56, the shield cutting device 123 of the shield device 148 cuts the molten nuclear fuel material 13 existing at the bottom of the furnace in the RPV2, and the cutting chips of the molten nuclear fuel material 13A are collected in the cutting waste storage tank. .. The cutter 125 of the shield cutting device 123 cuts the bottom of the RPV2 and the control rod drive housing 39. However, since the melt 13A contains the melted nuclear fuel material and the structure inside the furnace, the inside structure such as the steam dryer 7 and the steam separator 6 is not cut by the shield cutting device 123.

In this example, each effect produced in Example 1 can be obtained. Further, in this embodiment, since the in-core structure and the molten nuclear fuel material in the RPV2 are cut and carried out by using the shield device 148 having the shield cutting device 123, the nuclear fuel material is carried out in a shorter time than in the first embodiment. It can be performed.

When the method for carrying out the nuclear fuel material using the shield device 148 having the shield cutting device 123 is applied to the second embodiment, the method for carrying out the nuclear fuel material in the nuclear plant is as follows. When each of the operations of steps S1 and S45 to S48 of the second embodiment is carried out, and it is determined in step S49 that the boring object (cutting object) in the RPV is the steam dryer 7 and the steam separator 6. After the operations of steps S50 to S54, S2, S3 and S14 are performed, the operations of steps S55 and S56 performed in the third embodiment are performed. Further, when the operations of steps S1 and S45 to S48 of the second embodiment are carried out and it is determined in step S49 that the boring object in the RPV is the melt 13A existing in the bottom of the reactor in the RPV2. , Steps S40 and S41 carried out in the first embodiment do not install the traveling crane 32 above the reactor building 14 and do not further install the work house 16A and the preparation house 16B on the operating floor 143 of the reactor building 14. After that, the operations of steps S55 and S56, which are carried out in the third embodiment, are performed.

In this embodiment, each effect produced in Example 1 can be obtained, and further, since the shield device 148 is used, the time required for carrying out the nuclear fuel material can be shortened as compared with Example 2.

Each of the above-described embodiments can be applied not only to a boiling water reactor but also to a pressurized water reactor.

The concepts of the other inventions in this application will be described below.
(A1) Before cutting the nuclear fuel material in the nuclear fuel material presence region in the reactor vessel, the powder shield is injected into the reactor vessel and the nuclear fuel material presence region is injected into the powder shield. Cover with
The nuclear fuel cutting device is placed above the nuclear fuel material presence area covered with the powder shield in the reactor vessel.
The nuclear fuel material in the nuclear fuel material presence region is cut by the nuclear fuel cutting device, and the nuclear fuel material is cut.
A method for carrying out nuclear fuel material in a nuclear power plant that transfers the cut nuclear fuel material.
(A2) Before cutting the nuclear fuel material, a granular shield is injected into the reactor vessel, and after the injection of the granular shield into the reactor vessel is stopped, the nuclear fuel material is cut. Before, the powdery shield was injected into the reactor vessel, and the injected powdery shield was placed on the layer of the injected granular shield covering the nuclear fuel material existence region. The method for carrying out nuclear fuel material in the nuclear power plant according to (A1) covered with a body.
(A3) The work house is installed directly above the reactor vessel on the operating floor of the reactor building in which the reactor vessel is installed inside, and after the work house is installed on the operating floor, the powder shield is provided. The method for carrying out nuclear fuel material in a nuclear power plant according to (A1), wherein the injection into the reactor vessel is carried out.
(A4) The work house is installed directly above the reactor vessel on the operating floor of the reactor building in which the reactor vessel is installed inside, and after the work house is installed on the operating floor, the granular shield The method for carrying out nuclear fuel material in a nuclear power plant according to (A2), wherein the injection into the reactor vessel is carried out.
(A5) The nuclear fuel in the nuclear plant according to (A3) or (A4), wherein the nuclear fuel cutting device is lowered from the work house into the reactor vessel, and the nuclear fuel material is cut by the nuclear fuel cutting device. How to carry out the substance.
(A6) As the nuclear fuel cutting device, a nuclear fuel cutting device having a cutting portion for rotating and cutting the nuclear fuel material and a transfer passage for transferring the cut nuclear fuel material is used.
The cutting of the nuclear fuel material in the nuclear fuel material presence region is performed by the cutting portion that rotates the cutting portion while moving the cutting portion toward the lower end of the nuclear fuel material presence region.
The transfer of the cut nuclear fuel material is carried out by transferring the cut nuclear fuel material through the transfer passage, and carrying out the nuclear fuel material in the nuclear power plant according to any one of (A1) to (A4). Method.
(A7) The movement of the cutting portion toward the lower end of the nuclear fuel material presence region is performed by adding an extension pipe to the upper end of the transfer passage.
The method for carrying out nuclear fuel material in a nuclear power plant according to (A6), wherein the transferred nuclear fuel material is transferred through the transfer passage and the extension pipe.
(A8) Before injecting the granular shield, a photographing device is inserted into the reactor vessel to photograph the inside of the reactor vessel, and the image information in the reactor vessel photographed by the photographing device is captured. The method for carrying out nuclear fuel material in a nuclear plant according to (A2) or (A4) to be displayed on a display device.

1 ... Reactor, 2 ... Reactor pressure vessel, 4 ... Core, 9 ... Reactor containment vessel, 13 ... Molten nuclear fuel material, 13A, 13B ... Melt, 14 ... Reactor building, 16A ... Work house, 16B ... Preparation House, 18A, 18B ... Overhead crane, 43,43A ... Boring device, 44,44A ... Cutting device, 45,66A ... Outer cylinder, 46 ... Outer blade, 47 ... Inner blade, 48 ... Rotating shaft, 52A ... Inner blade shaft Clamp, 52B ... Outer blade shaft clamp, 53, 53A, 53B ... Moving table, 60 ... Extension pipe supply device, 61 ... Extension pipe support member, 63, 63B ... Extension pipe moving device, 65, 65D ... Grip part, 65A, 65B ... Arm clamp, 66, 66B ... Extension tube, 81.81A ... Cutting device, 123 ... Shield cutting device, 124 ... Rotating body, 125 ... Cutter, 126 ... Cylindrical body 127 ... Propulsion jack, 131 ... Support frame , 134A, 134B ... Rotating member, 135 ... Clamping device, 136 ... Recovery pipe holding member, 137 ... Recovery pipe supply device, 146 ... Clamping mechanism.

Claims (4)

A rotating body provided with a plurality of cutter devices for cutting the nuclear fuel material on the front surface, a propulsion unit having a plurality of propulsion jacks for advancing the rotating body, and a unit for transferring the cut nuclear fuel material formed in the propulsion unit. Using a shield cutting device having one transfer passage, the cutting of the nuclear fuel material in the region where the nuclear fuel material exists in the reactor vessel is performed by the plurality of cutter devices that are swiveled by the rotation of the rotating body, and the rotating body is used. A method for carrying out nuclear fuel material in a nuclear power plant, wherein the advancement is performed by the plurality of propulsion jacks, and the cut nuclear fuel material is transferred through the first transfer passage. The shield cutting device is moved in the reactor vessel from the top of the reactor vessel toward the bottom of the reactor vessel, and at the time of this movement, the shield cutting device moves the nuclear fuel in the nuclear fuel material presence region. besides material, the top of the front Kihara child reactor vessel, method for carrying out nuclear fuel material in the nuclear power plant according to claim 1 for cutting reactor internal component of the reactor vessel. An extension pipe having a second transfer passage formed therein is added to the shield cutting device so that the second transfer passage is connected to the first transfer passage, and the nuclear fuel cut by the plurality of cutter devices is added. The method for carrying out nuclear fuel material in a nuclear power plant according to claim 1 or 2, wherein the material is transferred from the first transfer passage to the second transfer passage. The method for carrying out nuclear fuel material in a nuclear power plant according to claim 3, wherein the extension pipe is added to the shield cutting device by using the extension pipe supply device.

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