JP6916239B2 - Reactor building overall cover device and reactor building preparation work method - Google Patents

Description

The present invention relates to the entire reactor building cover device and the reactor building preparation work method, and in particular, the entire reactor building cover device of the nuclear reactor building in which the core melting accident has occurred, and the atom of the nuclear plant in which the core melting accident has occurred. Reactor building preparation work method for opening the reactor pressure vessel and removing fuel debris .

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 inside the reactor pressure vessel. The fuel assembly loaded in the core is taken out of the reactor pressure vessel as a spent fuel assembly after experiencing the operation of the nuclear power plant in a predetermined number of operation cycles from the time when the fuel assembly is loaded in the core. Instead of the spent fuel assembly, a new fuel assembly with a burnup of 0 GWd / t is loaded into the core in the reactor pressure vessel.

For example, in a boiling water reactor, an emergency core cooling system equipped with multiple cooling systems is provided so that each fuel assembly loaded in the core in the reactor pressure vessel is constantly cooled. .. The installation of an emergency core cooling system prevents the occurrence of a core meltdown accident. However, with a very low probability, the function of the emergency core cooling system may be lost and the fuel assembly loaded in the core may melt. A method for taking out the molten nuclear fuel material when such a melting of the fuel assembly occurs is being studied.

Japanese Unexamined Patent Publication No. 2013-1975 describes a method for extracting molten nuclear fuel material from a reactor pressure vessel in an aerial environment. In this method of extracting molten nuclear fuel material, two work houses, which are isolation houses that prevent the scattering of radioactive nuclei into the external environment, are stacked and placed on the operating floor of the reactor building so as to cover the reactor wells, and are shielded. The plug is installed on the cab so as to cover the reactor well, and the reactor containment head, the reactor pressure vessel top lid, and the steam drying inside the reactor pressure vessel are used by the boring device installed on the shield plug. A hole is made in the vessel and the air-water separator. A camera inserted into the core through this hole observes the state of the core, and when the fuel assembly in the core is melting, a granular radiation shield is filled into the core through the hole.

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

In the method for taking out the molten nuclear fuel material described in Japanese Patent Application Laid-Open No. 2013-1985, four additional floors in which guide rails forming a 1/4 arc of one circle are attached to the upper surfaces of the guide rails are installed on the driver's floor. NS. By installing additional floors on the driver's floor, the guide rails on each additional floor are connected to form a single circular guide rail. An electromagnet suspended from an overhead crane in the isolation house is attached to the outer surface of the head of the reactor containment vessel, and the cutting device is provided at the lower end of the expansion tube of the cutting device while moving along the above guide rail. The head of the reactor containment vessel is cut with a cutting device attached to the tip of the arm. The cut head is pulled up into the isolation house by pulling up its electromagnet suspended from an overhead crane and carried out. For the upper lid of the reactor pressure vessel, the bolt fixing the upper lid to the reactor pressure vessel is removed, and then the upper lid is attracted by an electromagnet and pulled up into the isolation house. If the bolt that secures the top lid to the reactor pressure vessel is stuck and cannot be removed, the electromagnet suspended from the overhead crane in the isolation house is attached to the reactor pressure vessel, similar to the head of the reactor containment vessel. The top lid is cut into a circle with a cutting device that is attached to the outer surface of the top lid and moved along the guide rail described above, and the cut top lid is pulled up into the isolation house.

The steam dryer and the steam separator installed in the reactor pressure vessel are cut, and the cut pieces are taken out into the isolation house. In Japanese Patent Application Laid-Open No. 2013-1985, the fuel debris existing at the bottom of the reactor pressure vessel is subsequently taken out by using a boring device.

Further, Japanese Patent Application Laid-Open No. 2014-70946 has an opening formed in the side wall of the reactor building, and radiation is directed toward the control rod drive mechanism hatch formed in the biological shield surrounding the reactor containment vessel through the opening. It is described that an access passage is formed by a shield, and fuel debris that has fallen to the bottom of the reactor containment vessel is taken out through this access passage. In this fuel debris extraction method, a radiation shielding chamber is formed in the reactor building adjacent to the outer surface of the ecological shield and connected to the access passage, and the articulated arm of the articulated access device arranged in the radiation shielding chamber. The crusher attached to the tip of the pedestal crushes the fuel debris that has fallen to the bottom of the reactor containment vessel in the pedestal, and the crushed pieces of the fuel debris are grasped by the grip attached to the tip of the articulated arm and inside the pedestal. It is taken out from the radiation shield room and stored in the storage container in the radiation shield room.

Further, in Japanese Patent Application Laid-Open No. 2012-255742, in a nuclear power plant where the core fuel is melted and the reactor is decommissioned, the reactor building is covered with a secondary shielding tent, and the secondary shielding tent is further covered with a primary shielding tent. It is covered with a shield tent. Crane units are placed across the reactor building in the secondary shielding tent. This crane unit runs on guide rails installed on a plurality of columns installed outside the reactor building. Cut pieces such as furnace structures cut using a working device are stored in a storage container, and this storage container is placed on a transport trolley on a temporary storage table by a crane unit and transferred to a predetermined storage building.

Japanese Unexamined Patent Publication No. 2013-1975 Japanese Unexamined Patent Publication No. 2014-70946 Japanese Unexamined Patent Publication No. 2012-255742

In the method for extracting molten nuclear fuel material described in Japanese Patent Application Laid-Open No. 2013-1985, an isolation house is installed on the operating floor of the reactor building so as to cover the reactor well, and the reactor is installed at the upper end of the reactor well. The shield plug blocking the well is removed.

When removing the shield plug, the containment head in good condition is attached to the upper end of the reactor containment, so the airtightness of the reactor containment is maintained and the reactor containment vessel is maintained even in the event of a core melting accident. The radioactive material inside is not released into the reactor well formed above the containment head. However, if the containment head is impaired in airtightness, radioactive material in the containment may have been released into the reactor wells that are sealed with a shield plug. In such a case, by removing the shield plug that seals the reactor well, the radioactive material released into the reactor well invades the isolation house, and the inside of the isolation house is contaminated with the radioactive material. For this reason, radioactive substances accumulate in the isolation house itself and become a pollution source, which increases the dose equivalent rate of the surroundings and prevents workers from approaching the isolation house. In addition, since various equipment installed in the isolation house is also contaminated, it is necessary to decontaminate all the equipment in and out of the isolation house, which causes a decrease in workability.

In addition, when a hydrogen explosion occurs inside the reactor building due to a core meltdown accident, rubble and structural members to which radioactive substances that are supposed to be scattered on the operating floor of the reactor building 1 are attached. Work to remove falling objects such as pieces is carried out. Therefore, the method of removing the fallen object affects various operations thereafter.
In addition, there is a possibility of radioactive material leaking from the reactor containment vessel due to the effect of the hydrogen explosion, and there is a concern that this may be leaking from the reactor building.
Described method of JP 2012-255742 discloses, the primary, in order to cover the work area by the secondary shielding tent, after dismantling of the falling object, and an open working reactor pressure vessel is the next task There is a problem that it is not possible to secure a work area where the spent fuel unloading work can be performed in parallel.

An object of the present invention is to provide a reactor building whole cover device and a reactor building preparation work method for facilitating the work of opening the reactor pressure vessel and taking out fuel debris of a nuclear power plant in which a core meltdown accident has occurred. There is.

The entire reactor building cover device of the present invention is an entire reactor building cover device that covers the entire reactor building of a nuclear reactor in which a core meltdown accident has occurred, and includes columns provided at least at four corners of the reactor building. The upper surface of the space surrounded by the columns provided at the four corners and the isolation sheet for separating the radioactive substances provided so as to cover the four side surfaces are provided.

In the entire reactor building cover device of the present invention, frame members are provided on the upper portions of the columns provided at the four corners, and a traveling carriage having an article carry-in entrance is provided on the frame members on the operating floor of the reactor building. It is desirable that a traveling member and a traversing member that are moved two-dimensionally in the portion are attached.

The reactor building preparation work method of the present invention is a reactor building preparation work method for opening the reactor pressure vessel of a nuclear plant in which a core melting accident has occurred and taking out fuel debris, and is the entire reactor building preparation work method. This is done by covering the entire reactor building with a cover device.

According to the present invention, it becomes easy to open the reactor pressure vessel of a nuclear power plant in which a core meltdown accident has occurred and to take out fuel debris.

It is a vertical sectional view of the reactor building of a boiling water reactor. It is a top view of the operation floor of the reactor building. Is a flowchart illustrating some steps of the extraction process of fuel debris applied to boiling Agamizu reactor plant. Is a flowchart showing the remaining steps of the extraction process of fuel debris. It is explanatory drawing which shows the state which installed the whole cover device which covers the whole reactor building mainly on the upper part from the operation floor which removes a fallen object. It is explanatory drawing which shows the working concept of removing a fallen object using a separating film. It is explanatory drawing which shows the work concept of removing a fallen object by using the device inclusion container without using the isolation film. It is explanatory drawing which shows the state which installed the radiation shielding container in the dryer separator pool. It is explanatory drawing which shows the carry-in state of the drilling apparatus into the radiation shielding container installed in the dryer separator pool. It is explanatory drawing which shows the state of the drilling device installed in the front surface of the throttle plug to be drilled in a radiation shielding container. It is explanatory drawing which shows the state which punches a throttle plug using a drilling device. It is explanatory drawing which shows the state which took out the cut block of a throttle plug. It is explanatory drawing which shows the installation state of the handrail removal device in a radiation shielding container. It is explanatory drawing which shows the removal work of the handrail of the containment vessel head arranged in the reactor well using the handrail removal device. It is explanatory drawing which shows the installation state of the decontamination apparatus in a radiation shielding container. It is explanatory drawing which shows the decontamination work in the reactor well using the decontamination apparatus. It is explanatory drawing which shows the installation state of the radiation shield installation device in a radiation shield container. It is explanatory drawing which shows the work of carrying the radiation-shielding bag into the reactor well using the radiation-shielding body installation device. It is explanatory drawing which shows the state of the radiation bag which was carried into the reactor well and expanded by the water supply to the inside. It is explanatory drawing which shows the state which covered the containment vessel head by a plurality of radiation shielding bags arranged in a reactor well and expanded by water supply. It is explanatory drawing which shows the state which installed the isolation house which covers the dryer separator pool and the reactor well on the operation floor of the reactor building. It is explanatory drawing which shows the removal work of a shield plug. It is explanatory drawing which shows the state which the removed shield plug is stored in the carry-out container arranged on the upper surface of the radiation shielding container in the isolation house. It is explanatory drawing which shows the removal work of a slot plug. It is explanatory drawing which shows the state in the process of transporting the removed slot plug. It is explanatory drawing which shows the state which the removed slot plug is stored in the carry-out container arranged on the upper surface of the radiation shielding container in the isolation house. It is explanatory drawing which shows the state which removed the side wall on the reactor well side of the radiation shielding container installed in the dryer separator pool. The isolation wall that divides the inside of the isolation house into the first area directly above the dryer separator pool and the second area directly above the reactor well, and the installation state of the new side wall of the radiation shielding container to the reactor well side, and It is explanatory drawing which shows the mounting state of each of the new side wall of the radiation shielding container to the reactor well side, and the work of carrying out the radiation shielding bag in the reactor well. It is explanatory drawing which shows the cutting of the containment vessel head by the cutting recovery device provided in the radiation shielding container, and the pool fuel take-out process is shown. It is explanatory drawing which shows the cutting of the heat insulating material by the cutting recovery device provided in the radiation shielding container. It is explanatory drawing which shows the removal of a baffle plate, and the attachment work of a pressure vessel support and a radiation shield plate. It is explanatory drawing which shows the investigation process which examines the inside of the reactor containment vessel. It is explanatory drawing which shows the state which arranged the isolation vessel covering the pressure vessel head inside each of the reactor well and the 2nd area in the isolation house. It is explanatory drawing which shows the state which the pressure vessel head is lifted in the isolation vessel. It is explanatory drawing which shows the decontamination work of the inner surface of the pressure vessel head lifted in the isolation vessel. It is explanatory drawing which shows the carry-out of the decontaminated pressure vessel head out of the isolation vessel. It is explanatory drawing which shows the removal work of the steam dryer in the isolation container. It is explanatory drawing which shows the removal of the removed steam dryer to the outside of the isolation container. It is explanatory drawing which shows the carry-in of the removed steam dryer into the radiation shielding container installed in the dryer separator pool. It is explanatory drawing which shows another example of the removal work of the steam dryer in the isolation container. It is explanatory drawing which shows the cutting operation of the structure in the reactor in the reactor pressure vessel by the rotary cutting apparatus. It is a side view of the rotary cutting apparatus shown in FIG. 39. It is a YY arrow view of FIG. 40. It is explanatory drawing which shows the carry-out of the carry-out container through the water-sealed area in the containment vessel head cutting of FIG. 27. It is explanatory drawing which shows the other figure of the investigation process which examines the inside of the reactor containment vessel of FIG. It is explanatory drawing which shows the shredding process which is another figure of the removal process of the pressure vessel head of FIGS. 31 to 34. It is explanatory drawing which shows the shredding in the radiation shielding container which is a separate view of the removal process of the steam dryer of FIGS. 35 to 37.

The extraction method of removing method and the fuel debris drop under product will be described below with reference to FIGS. Fuel debris extraction method is applied to a boiling water nuclear power plant. Fuel debris extraction method includes removal of the opening and the fuel debris of the reactor pressure vessel.

Opening a portion at which the reactor pressure vessel of fuel debris extraction method method, preparatory work shown in FIG. 3 (including the steps of steps S1 to S6) and the reactor opened operations (step S7~S13 Includes each step). This fuel debris removal method includes a fuel debris removal operation (including each step of steps S14 to S16) that has fallen to the bottom of the reactor containment vessel shown in FIG.

Before describing the fuel debris extraction method, a schematic configuration of the fuel debris boiling water nuclear power plant extraction method is applied will be described with reference to FIGS.

The boiling water reactor 1 includes a reactor 2 and a reactor containment vessel 17. The reactor containment vessel 17 is installed in the reactor building 23, and the containment vessel head 18 which is a lid is attached to the upper end thereof and is sealed. The reactor containment vessel 17 has a dry well 19 formed inside and a pressure suppression chamber 21 in which a pressure suppression pool filled with cooling water is formed. One end of the vent passage connected to the dry well 19 is immersed in the cooling water of the pressure suppression pool in the pressure suppression chamber 21. The reactor containment vessel 17 is surrounded by a biological shield 100 that becomes a part of the reactor building 23.

Shield plugs 28, which are radiation shields divided into a plurality of parts, are arranged directly above the containment vessel head 18, and these shield plugs 28 are arranged in the reactor well 25 and are placed on the operating floor 24 of the reactor building 23. is set up. The shield plug 28 seals the reactor well 25. A dryer separator pool (temporary equipment storage pool) 26 and a fuel storage pool 27 are arranged adjacent to the reactor well 25 and surrounded by a working floor 24. The dryer separator pool is hereinafter referred to as DSP. The DSP 26, the reactor well 25 and the fuel storage pool 27 are arranged in a straight line as shown in FIG. The DSP 26 and the reactor well 25 are connected by a water channel, which is blocked by a plurality of throttle plugs (gate members) 29A at least during the operation of the boiling water reactor 1. These throttle plugs 29A are stacked on the upper surface of a concrete protrusion 57 formed at the bottom of the water channel. The reactor well 25 and the fuel storage pool 27 are also connected by a water channel, which is blocked by a plurality of stacked throttle plugs (gate members) 29B at least during the operation of the boiling water reactor 1.

The reactor 2 includes a reactor pressure vessel 3 to which a pressure vessel head 4 which is a lid is attached, a core 7 loaded with a plurality of fuel assemblies 8 containing nuclear fuel material, an air-water separator 11, and steam drying. It is equipped with a vessel 12 and the like. The core 7, the steam separator 11, and the steam dryer 12 are arranged in the reactor pressure vessel 3. A core shroud 6 installed in the reactor pressure vessel 3 surrounds the core 7. The lower end of each fuel assembly 8 loaded in the core 7 is supported by the core support plate 9, and the upper end is held by the upper grid plate 10. The steam separator 11 is arranged above the upper grid plate 10 located at the upper end of the core 7, and the steam dryer 12 is arranged above the steam separator 11.

A plurality of control rod guide pipes 13 are arranged below the core support plate 9 in the reactor pressure vessel 3.
Control rods (not shown) that are taken in and out of the fuel assembly 8 in the core 7 to control the reactor output are arranged in each control rod guide pipe 13. A plurality of control rod drive mechanism housings 14 are attached to the lower mirror portion 5 of the reactor pressure vessel 3. Control rod drive mechanisms (not shown) are installed in the respective control rod drive mechanism housings 14 and are connected to the control rods in the control rod guide pipe 13.

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

The reactor pressure vessel 3 is installed on a cylindrical pedestal 15 provided on a concrete mat 16 provided at the bottom of the reactor containment vessel 7. A tubular γ-ray shield 22 is installed at the upper end of the pedestal 15 and surrounds the reactor pressure vessel 3. A lower plenum 20 is formed in the pedestal 15 below the reactor pressure vessel 3.

In such a boiling water reactor 1, in a state where the reactor is scrammed and the reactor output is reduced, all the power supplies supplied to the boiling water reactor 1 are temporarily lost to cool the emergency core. 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 stop working and the cooling of each fuel rod contained in each fuel assembly 8 in the core 7 is impaired, these fuel rods will be affected. The nuclear fuel material contained therein is melted, and the melting of the nuclear fuel material also melts the structural members of the fuel assembly 8, for example, the cladding of the fuel rods, the channel box of the fuel assembly 8, and the upper and lower tie plates.
Fuel debris 39A, which is a melt of the nuclear fuel material and the structural members of the fuel assembly 8, may fall on the inner surface of the lower mirror portion 5 which is the bottom of the reactor pressure vessel 3. The fuel debris 39A may contain a melt of a reactor internal structure such as a core support plate 9. The fuel debris 39A that has melted and dropped onto the inner surface of the lower mirror portion 5 is cooled and solidified.

In the unlikely event that the fuel debris 39A falls to the bottom of the reactor pressure vessel 3, the solidified fuel debris 39A is carried out of the reactor pressure vessel 3, and the fuel debris 39A is further discharged. Decommissioning is carried out for the boiling water reactor 1 in which the fall has occurred. Further, a part of the fuel debris 39A that has fallen to the bottom of the reactor pressure vessel 3 is located at the bottom of the reactor containment vessel 17 in the pedestal 15, that is, concrete, further below the lower mirror portion 5 of the reactor pressure vessel 3. It may fall on the mat 16. The fuel debris that has fallen to the bottom of the reactor containment vessel 17 in the pedestal 15 is referred to as fuel debris 39B.

When a core meltdown accident occurs in which the nuclear fuel material in the core 7 melts, as shown in FIG. 5, nothing exists in the DSP 26, and the DSP 26 and the reactor well 25 are separated by a plurality of slot plugs 29A. ing. Further, a handrail 31 is provided on the top of the containment vessel head 18, and the pressure vessel head 4 is covered with a heat insulating material 30. A baffle plate 76 that becomes a part of the bottom of the reactor well 25 is arranged between the reactor pressure vessel 3 and the reactor containment vessel 17, and the baffle plate 76 is the reactor pressure vessel 3 and the reactor containment vessel 17. It is attached to. It is assumed that a gas containing radioactive substances (for example, Cs-137, etc.) has flowed into the reactor well 25 through the damaged portion of the containment vessel head 18 due to the occurrence of the core meltdown accident.

First, when a hydrogen explosion occurs inside the reactor building due to a core meltdown accident, rubble and structural members to which radioactive substances that are supposed to be scattered on the operating floor of the reactor building 1 are attached. The reactor building preparation work mainly for removing fallen objects such as pieces will be described with reference to FIGS. 5A to 5C.
In the reactor building preparation work, first, the building cover that had been erected on the operating floor 24 of the existing reactor building 23 at a place that needs to be removed for each work is dismantled (step ST1).

After that, as shown in FIG. 5A, an overall cover device that covers the entire reactor building 23 is installed, mainly above the operation floor 24 for removing falling objects (step ST2). FIG. 5A (a) is a view of the entire cover device 300 as viewed from above. 5A (b) is a side sectional view of the entire cover device including the reactor building 1 in FIG. 5A (a). As shown in FIG. 5A (a), the overall cover device 300 has columns erected at least at the four corners of the reactor building 1 and is isolated so as to cover the upper surface of the device and its four sides in order to isolate radioactive materials. Sheets 303A and 303B are provided. The overall cover device 300 is provided with a traveling member and a traversing member that two-dimensionally move the traveling carriage 301 having the article carry-in entrance 301A on the upper part of the driver's floor 24 to the frame member that defines the shape thereof.

According to this overall cover device, a sufficient work space can be formed between the traveling carriage 301 and the driver's floor 24, and after the fallen object removal work is completed, for example, a plurality of works can be performed independently and in parallel. can.

FIG. 5B is a diagram showing a work concept of removing a falling object 310 using the isolation film 309. In this example, as shown in FIG. 5B (a), the load device 306 is provided on the upper side of the article carry-in port 301A, and the gripping tool 308 is provided so as to be able to move up and down from the traveling carriage 307 of the load device 306. Have.

First, the article carry-in inlet 301A is moved to the upper part of the position where the falling object 310 exists based on, for example, a survey conducted in advance, and the picking tool 308 is conveyed to the upper part of the article carry-in entrance 301A (FIG. 5B (a)). After that, the picking tool 308 is lowered and inserted from the article carry-in entrance 301A to grip the falling object 310 (FIG. 5B (b)). Next, the falling object 310 is pulled up through the article carry-in entrance 301A, the picking tool 308 is rotated, the falling object 310 being gripped is wrapped with the isolation film 309, and the rotated and squeezed position is fused. Separate (Fig. 5B (c)). After that, the fallen object wrapped in the isolation film 309 is moved to the position of the container cradle 312 where the carry-out container 311 is located and stored (FIG. 5B (d)). After that, the hook of the crawler crane 305 is moved to the position of the container cradle 312, the carry-out container 311 is carried out to a predetermined place, and the article carry-in inlet 301A is closed (FIG. 5B (e)).
In this example, the traveling carriage 307 is used, but the picking tool 308 may be raised and lowered by a crane that moves integrally with the article carry-in entrance 301A.

FIG. 5C is a diagram showing a work concept of removing a falling object 310 by using an apparatus inclusion container 313 without using the isolation film 309. FIG. 5C (a) in this example shows a state in which the device inclusion container 313 is placed on the article carry-in port 301A without the isolation film 309. A traveling carriage 307 and a picking tool 308 are built in the device inclusion container 313. Further, an opening / closing sheet 314 that can be opened / closed is provided on the lower surface of the device inclusion container 313 and the upper surface of the article carry-in entrance 301A.

First, the article carry-in inlet 301A is moved to the upper part of the position where the falling object exists based on, for example, a survey conducted in advance, and then the device inclusion container 313 is placed on the article carry-in inlet 301A (FIG. 5C (a)). .. Next, both opening / closing sheets 314 are opened, the picking tool 308 is lowered and inserted from the article carry-in entrance 301A, and the falling object 310 is gripped (FIG. 5C (b)). After that, the fallen object 310 is collected in the device inclusion container 313, and both opening / closing sheets 314 are closed (FIG. 5C (c)). Then, for example, the crawler crane 305 lifts the device-encapsulating container 313 that has collected the fallen object 310 (FIG. 5C (d)), moves it to the position of the container cradle 312 where the carry-out container 311 is located, opens the open / close sheet, and stores the fallen container. The thing is moved to the carry-out container (Fig. 5C (e)). After that, the device inclusion container 313 is lifted again by the crawler crane 305 and moved to the next collection position. After the movement, the carry-out container 311 is lifted by another crawler crane 305 and carried out to a predetermined place (FIG. 5C (f)).
In this example, the device inclusion container 313 is placed on the article carry-in inlet 301A to collect the fallen object, but a traveling trolley for moving the device inclusion container 313 and the device inclusion container 313 is provided below the article carry-in inlet 301A. May be.

After performing the above-mentioned reactor building preparatory work, the overall cover device installed in the work space formed between the traveling carriage 301 and the driver's floor 24 has an exhaust device (not shown) connected to the inside thereof. Since airtightness can be ensured by controlling the negative pressure, it can be commonly used for the subsequent opening work of the reactor pressure vessel and the spent fuel unloading work. Further, as will be described later, in the opening work of the reactor pressure vessel, the carry-out container containing the take-out equipment of the equipment in the reactor well can be used for carrying out from the article carry-in inlet 301A. Further, even in the spent fuel unloading work from the fuel storage pool 27, the article loading port 301A can be used for loading and unloading the contaminated equipment used in the pool, and can contribute to performing both operations in parallel. In addition, since it covers the entire reactor building, if radioactive material leaks from the reactor containment vessel 17 and leaks from the reactor building, the entire cover device will spread it to the surrounding environment. Can be prevented.

As a result, after removing the rubble on the operation floor, it is not necessary to replace the dedicated cover according to the subsequent work, and it is not necessary to sequentially perform the reactor pressure vessel opening work and the spent fuel unloading work. , The time required for reactor dismantling work can be further shortened.

Next, the extraction method of fuel debris below. First described preparation in a method of releasing the reactor pressure vessel is part of a fuel debris extraction method. This preparatory work is a preparatory work for the reactor opening work.

As an example for preparing the equipment temporary storage pool as an isolation area for shielding and preventing the diffusion of radioactive substances, a radiation shielding container is installed in the DSP (step S1). A mobile crawler crane (not shown) installed outside the reactor building 23 is used to lift the radiation shielding container 32 and install it inside the DSP 26 (see FIG. 6). It should be noted that this crane may be any one that can carry in and out heavy objects such as a gantry crane and a tower crane. In the radiation shielding container 32, the radiation shielding plate 33 having the opening 36A formed is attached to the radiation shielding container 32 as a ceiling member, and the opening 36B is formed on the side wall on the reactor well 25 side. A mobile door 34 that opens and closes the opening 36A is attached to the radiation shielding container 32. Further, a mobile door 35 for opening and closing the opening 36B is attached to the inner surface of the side wall on the reactor well 25 side. The opening 36B is closed by the door 34, and the opening 36B is closed by the door 35.

A through hole is formed in the throttle plug (step S2). The isolation chamber 40 in which the drilling device 41 is housed is suspended by a crawler crane and carried into the space 37 in the radiation shielding container 32 through the opening 36A (see FIG. 7). At this time, the door 34 is open. A carriage 40A is attached to the lower surface of the isolation chamber 40, and an opening 40E is formed on one side wall of the isolation chamber 40. The opening 40E is opened and closed by a door 40B movably attached to the inner surface of its side wall. An annular sealing device 40C surrounding the opening 40E is attached to the outer surface of its side wall of the isolation chamber 40.

The drilling device 41 is arranged in the space 40D in the isolation chamber 40 and is movably attached to the upper end of the support member 42 attached to the bottom surface of the isolation chamber 40. After the isolation chamber 40 is carried into the radiation shielding container 32, the door 34 is closed, and the isolation chamber 40 is moved by the carriage 40A to the side wall of the radiation shielding container 32 on the reactor well 25 side. The sealing device 40C is pressed against the inner surface of the side wall of the radiation shielding container 32 where the opening 36B is formed by the movement of the isolation chamber 40 so as to surround the opening 36B (see FIG. 8). The door 35 is opened after the sealing device 40C is pressed against the side wall. The opening 36B communicates with the opening 40E formed in the isolation chamber 40, and communicates with the space 40D in the isolation chamber 40 by opening the door 40B.

The throttle plug 29A is cut into blocks by driving a drilling device (for example, a wire saw) 41 and moving the drilling device 41 toward one throttle plug 29A made of concrete. The cutting position of the throttle plug 29A using the drilling device 41 is a position lower than the lower surface of the shield plug 28 located at the lowest position among the shield plugs 28 blocking the reactor well 25 (see FIG. 9). .. The block 44 of the shield plug 28 carved out by the drilling device 41 is carried into the isolation chamber 40 (see FIG. 10). As a result, a through hole 43 is formed in the shield plug 28, the space in the reactor well 25 and the isolation chamber 40 communicate with each other, and the gas containing radioactive substances existing in the reactor well 25 passes through the through hole 43 and the opening. It flows into the isolation chamber 40 through 36B and 40E. The door 40B is then closed to close the opening, and immediately the door 35 is closed to close the opening.

The isolation chamber 40, which is sealed with the door 35 closed and contains a gas containing radioactive substances, is carried out from the inside of the DSP 32 to the ground by a crawler crane through the opening 36A. After that, the isolation chamber 40 containing the drilling device 41 is disposed of. At the time of this disposal, the gas containing radioactive substances in the isolation chamber 40 is supplied to the purification device and removed by the purification device.

The handrail provided on the containment vessel head is removed (step S3). Another isolation chamber 40 in which the handrail removing device 45 is housed is carried into the space 37 in the radiation shielding container 32 through the opening 36A as in the step S2. After the isolation chamber 40 is brought in, the door 34 is closed. The isolation chamber 40 is moved within the radiation shielding vessel 32 until the sealing device 40C contacts the inner surface of the side wall of the radiation shielding vessel 32 on the reactor well 25 side (see FIG. 11). The door 35 is opened after the sealing device 40C is pressed against the side wall.

The handrail removing device 45 has a slide mechanism 45B attached to the upper end portion of the support member 42, a telescopic pipe 45A installed on the slide mechanism 45B, and two working arms 45C attached to the tip end portion of the telescopic pipe 45A. A gripper (not shown) is attached to the tip of one work arm 45C, and a cutter (pipe cutter) is attached to the tip of another work arm 45C. These working arms 45C have multiple joints and can be freely bent up, down, left and right. The working arm 45C is composed of, for example, a plurality of actuators 200'connected to each other as described in Japanese Patent Application Laid-Open No. 2011-106529.

The door 40B opens and the space 40D in the isolation chamber 40 communicates with the reactor well 25. The expansion tube 45A is inserted into the through hole 43 by the movement of the slide mechanism 45B, and the expansion tube 45A is further extended toward the reactor well 25. The handrail 31 attached to the containment vessel head 18 is grasped by the gripping tool of one working arm 45C and cut by the cutter of the other working arm 45C (see FIG. 12). The cut piece of the handrail 31 gripped by the above-mentioned gripping tool is moved into the isolation chamber 40 by the movement of the slide mechanism 45B and the expansion / contraction tube 45A, and is housed in the isolation chamber 40. In this way, the handrail 31 is sequentially cut. After all the handrails 31 have been removed, the work arm 45C of the handrail removal device 45 is housed in the isolation chamber 40 and the doors 40B and 35 are closed. The isolation chamber 40 containing the handrail removing device 45 and the cut pieces of the handrail 31 is suspended by a crawler crane and transported from the radiation shielding container 32 to the ground through the opening 36A.

A camera (not shown) is attached to the tip of the telescopic tube 45A to which the work arm 45C is attached, and the camera captures the work in the reactor well 25 (for example, cutting the handrail 31). The image taken by the camera is transmitted to the monitor of the operation floor of the reactor building 23 or the operation room installed in the annex building, and is monitored by the workers. This camera is also attached to the tip of each telescopic tube 45A of the decontamination device 46 and the shield transfer device 47 used in steps S4 and S5 described later.

The inside of the reactor well is decontaminated (step S4). Another isolation chamber 40 in which the decontamination device 46 is housed is carried into the radiation shielding container 32 through the opening 36A as in the step S2, and then the door 34 is closed. The sealing device 40C of the isolation chamber 40 is brought into contact with the inner surface of the side wall of the radiation shielding container 32 on the reactor well 25 side (see FIG. 13). The door 35 is opened after the sealing device 40C is pressed against the side wall.

Similar to the handrail removing device 45, the decontamination device 46 has a slide mechanism 45B, a telescopic tube 45A, and a working arm 45C attached to the upper end of the support member 42. The injection nozzle 46A is attached to the tip of the work arm 45C.

The door 40B opens and the space 40D in the isolation chamber 40 communicates with the reactor well 25. As the slide mechanism 45B and the telescopic pipe 45A move toward the reactor well 25, the working arm 45C and the injection nozzle 46A are inserted between the containment vessel head 18 and the shield plug 28 in the reactor well 25. Washing water is injected from the injection nozzle 46A, and for example, the lower surface of the shield plug 28 is decontaminated (see FIG. 14). The wash water is supplied by a water supply hose (not shown) installed along the telescopic pipe 45A and the work arm 45C. This water supply hose extends from the inside of the isolation chamber 40 to the outside of the radiation shielding container 32 and is connected to the make-up water system. The expansion and contraction tube 45A is expanded and contracted, and the work arm 45C is bent up, down, left and right to decontaminate the outer surface of the containment vessel head 18 and the inner surfaces of the throttle plugs 29A and 29B. After the decontamination in the reactor well 25 is completed, the working arm 45C and the injection nozzle 46A of the decontamination device 46 are housed in the isolation chamber 40, and the doors 40B and 35 are closed. The isolation chamber 40 containing the decontamination device 46 is suspended by a crawler crane and transported from the radiation shielding container 32 to the ground through the opening 36A.

The cleaning water that was sprayed from the injection nozzle 46A toward the lower surface of the shield plug 28 during decontamination and dropped was received by a cleaning water tray (not shown) attached to the work arm 45C and connected to the cleaning water tray. It is stored in a drainage tank (not shown) provided in the isolation chamber 40 through a drainage hose. The wash water used for decontaminating the outer surface of the containment vessel head 18 and the inner surfaces of the throttle plugs 29A and 29B cannot be received by the wash water tray and falls on the upper surface of the baffle plate 76 in the reactor well 25. .. The wash water that has fallen on the upper surface of the baffle plate 76 is drained by driving a pump (not shown) connected to the drain tank of the isolation chamber 40 and sucking it with a drain hose (not shown) connected to this pump. It is stored in the tank. The water stored in the drainage tank is also transported to the ground together with the isolation chamber 40.

A first radiation shield is installed in the reactor well (step S5). Another isolation chamber 40 containing the shield transfer device 47 and the folded shield bag 48 is carried into the radiation shield container 32 through the opening 36A as in the step S2, and then the door. 34 is closed. The shielding bag 48 is a bag made of a composite sheet composed of a sheet having elastic properties and a fiber that maintains strength, and is folded. This sheet may incorporate fibers having high strength, high elasticity, and high ductility, if necessary. The shielding bag 48 may be made of elastic rigid rubber. The sealing device 40C of the isolation chamber 40 is brought into contact with the inner surface of the side wall of the radiation shielding container 32 on the reactor well 25 side (see FIG. 15). The door 35 is opened after the sealing device 40C is pressed against the side wall.

The shield body transport device 47 has a slide mechanism 45B, a telescopic pipe 45A, and a work arm 45C attached to the upper end portion of the support member 42, similarly to the handrail removal device 45. The gripper 47A is attached to the tip of the work arm 45C.

The door 40B opens and the space 40D in the isolation chamber 40 communicates with the reactor well 25. In the space 40D, the gripper 47A grabs one shielding bag 48 existing in the space 40D. As the slide mechanism 45B and the telescopic pipe 45A move toward the reactor well 25, the work arm 45C and the gripper 47A holding the shielding bag 48 move in the reactor well 25 to contain the containment vessel head 18 and the shield plug 28. Is inserted between. The shielding bag 48 gripped by the gripping tool 47A is moved above the containment vessel head 18 to a predetermined position in the reactor well 25 (see FIG. 16). After that, a water supply hose (not shown) installed along the telescopic pipe 45A and the work arm 45C is connected to a check valve provided in the bag 48, and the water supplied by the water supply hose is equipped with a check valve. It is supplied into the shielding bag 48 via a one-touch coupler. The shielding bag 48 expands due to the supply of water, covers a part of the containment vessel head 18, and is arranged between the containment vessel head 18 and the shield plug 28 (see FIG. 17).

The water supply hose installed along the working arm 45C is removed from the one-touch coupler with the check valve, and the gripping tool 47A is returned to the space 40D in the isolation chamber 40 by the movement of the slide mechanism 45B and the telescopic pipe 45A. Here, the gripping tool 47A grabs the other shielding bag 48, moves again to a predetermined position in the reactor well 25, and transfers the shielding bag 48 to the predetermined position. Water is also supplied into the shielding bag 48, and the shielding bag 48 expands. As described above, the required number of shielding bags 48 are transferred into the reactor well 25 and expanded by water, so that the containment vessel head 18 is arranged between the containment vessel head 18 and the shield plug 28. It is covered with a plurality of water-inflated shielding bags 48 (see FIG. 18). These shielding bags 48 filled with water serve as a radiation shielding body (first radiation shielding body).

Since the through hole 43 is formed in the throttle plug 29A, the containment vessel head 18 and the shield plug 28 are passed through the through hole 43 from the radiation shielding container 32 installed in the DSP 26 by using the shield transfer device 47 in the isolation chamber 40. Can be easily transferred between. Therefore, the water-filled shielding bag 48, that is, the first radiation shielding body, which covers the containment vessel head 18, can be easily installed.

By arranging these shielding bags 48 filled with water between the containment vessel head 18 and the shield plug 28, radiation from below the containment vessel head 18 is emitted from these shielding bags 48 filled with water. It can be shielded. As a result, by accessing the decontamination work in the contaminated reactor well and the installation work of the shield from the equipment temporary storage pool side, the diffusion of radioactive materials and the leakage of radiation from the reactor well are installed in the equipment temporary storage pool. It can be suppressed by the radiation shielding container, and it is possible to prevent the leakage of radioactive dust and dose directly to the driver's floor. Further, as will be described later, even when the shield plug 28 is removed, the dose on the driver's floor 24 can be reduced. Further, since the shielding bags 48 filled with water are arranged in the reactor well 25, the air flow in the reactor well 25 is obstructed and the diffusion of radioactive substances can be prevented.

After the installation of a predetermined number of shield bags filled with water in the reactor well 25 is completed, the work arm 45C and the gripper 47A of the shield transfer device 47 are housed in the isolation chamber 40, and the doors 40B and 35 are housed in the isolation chamber 40. Is closed. The isolation chamber 40 accommodating the shield transport device 47 is suspended by a crawler crane and transported from the radiation shield container 32 to the ground through the opening 36A.

During each of the steps S1 to S6, the upper surface of the shield plug 28 that seals the reactor well 25 is covered with the curing sheet 38. The curing sheet 38 suppresses the leakage of radionuclides from between the shield plugs 28.

The isolation house is installed on the operating floor of the reactor building (step S6). The isolation house 49 is transported onto the operating floor 24 of the reactor building 23 using a crawler crane, and the isolation house 49 is installed on the operating floor 24 (see FIG. 19). The isolation house 49 covers the DSP 26, that is, the radiation shielding vessel 32 and the reactor well 25. An opening (not shown) that serves as an entrance to the inside and outside of the isolation house 49 is formed on the side wall of the isolation house 49, and a door (not shown) that opens and closes the opening is movably attached. Workers can enter the space 53 in the isolation house 49 from above the driver's floor 24 through the door-opened opening formed in the side wall of the isolation house 49. An overhead crane 50 including a traveling carriage and a traversing carriage is movably installed on a guide rail 51 installed near the ceiling in the space 53 in the isolation house 49. A rotary drum (not shown) for winding and rewinding the wire 56 attached to the grip 52 is attached to the traversing carriage of the overhead crane 50.

As described above, each step of the preparatory work in the method of opening the reactor pressure vessel is completed. Next, the reactor opening operation in the method of opening the reactor pressure vessel will be described.

Remove the shield plug (step S7). An annular isolation film storage container 73 is arranged in the isolation house 49 on the radiation shielding container 32, the driver's floor 24, and the throttle plug 29B so as to surround the throttle plug 29A and the shield plug 28. The isolation film 54 taken out from the isolation film storage container 73 is arranged so as to cover above the throttle plug 29A and the shield plug 28. The gripping tool 52 of the overhead crane 50 grips a hanging tool (not shown) attached to one shield plug 28 from above the isolation film 54 (see FIG. 19). The wire 56 is wound up and the shield plug 28 is lifted to a predetermined position (see FIG. 20). Then, the lifted shield plug 28 is wrapped with the isolation film 54, the isolation film 54 is welded at the position X shown in FIG. 20 which is wrapped and squeezed, and the isolation film 54 is cut at the welded portion.

After that, the overhead crane 50 is moved, and the shield plug 28 wrapped in the isolation film 54 is made of the radiation shield material placed on the radiation shield plate 33 attached to the radiation shield container 32 in the isolation house 49. It is stored in the carry-out container 55 (see FIG. 21). The carry-out container 55 containing the shield plug 28 is carried out onto the driver's floor 24 through the above-mentioned opening in which the door is opened, is further carried to the ground using a crawler crane, and is further carried to a predetermined storage location. .. The remaining shield plug 28 is also conveyed in the same manner.

Remove the throttle plug (step S8). Although all the shield plugs 28 have been removed, since the containment vessel head 18 is covered with a water-filled shield bag 48, radiation from below the containment vessel head 18 is a water-filled shield. It is shielded by the bag 48 and does not reach the space 53 in the isolation house 49. The isolation film 54 taken out from the isolation film storage container 73 is arranged so as to cover the throttle plug 29A and the upper part of the water-filled shield bag 48 in the reactor well 25. The grip 52 of the overhead crane 50 grips a suspension (not shown) attached to one throttle plug 29A from above the isolation film 54 (see FIG. 22). The wire 56 was wound up, the throttle plug 29A was lifted to a predetermined position, the lifted throttle plug 29A was wrapped with the isolation film 54, and the isolation film 54 was welded and welded at the wrapped and squeezed position in the same manner as the shield plug 28. The isolation film 54 is cut at the portion (see FIG. 23).

Then, the overhead crane 50 is moved, and the shield plug 28 wrapped in the isolation film 54 is stored in the carry-out container 55 arranged in the isolation house 49 (see FIG. 24). The carry-out container 55 containing the throttle plug 29A is transported to the ground and further to a predetermined storage location in the same manner as the carry-out container 55 containing the shield plug 28. The remaining throttle plug 29A is also conveyed in the same manner.

After that, each step S8A to S8D, which is a part of the reactor opening operation and is not shown in FIG. 3, is carried out. Each step of steps S8A to S8E will be described below.

The side wall of the radiation shielding container 32 on the reactor well 25 side is removed (step S8A). The side wall of the radiation shielding container 32 on the reactor well 25 side is removed from the radiation shielding container 32 with the door 35 attached, and is lifted by the overhead crane 50 and transferred to the space 53 in the isolation house 49. Further, this side wall is transferred from the inside of the isolation house 49 onto the driver's floor 24 outside the isolation house 49, and is transported to the ground. If necessary, the side wall is cut into a plurality of cut pieces and transferred for each cut piece. FIG. 25 shows a state in which the side wall is removed.

The protrusion formed at the bottom of the channel connecting the DSP and the reactor well is removed (step S8B). The isolation chamber 40 in which the drilling device 41 used in step S2 is housed is transported from the ground onto the operation floor 24 by a crawler crane, and is moved into the isolation house 49 through the above-mentioned opening formed in the isolation house 49. NS. Although not shown in FIG. 25, the isolation chamber 40 is carried into the radiation shielding container 32 through the opening 36A suspended from the overhead crane 50 and opened. Further, the isolation chamber 40 moves toward the reactor well 25 along the bottom surface of the radiation shielding vessel 32 and is stopped near the protrusion 57 formed at the bottom of the channel connecting the DSP 26 and the reactor well 25. .. A drilling device (eg, a wire saw) 41 is used to cut the protrusion 57 without damaging the water-filled bag 48 covering the containment head 18. A plurality of blocks (not shown) of the cut protrusions 57 are housed in the space 40D in the isolation chamber 40. The isolation chamber 40 accommodating these blocks is carried into the isolation house 49 through the opening 36A, and is further transported onto the driver's floor 24 outside the isolation house 49 and to the ground, contrary to the case of carrying in. .. As shown in FIG. 26, a flat bottom surface 57A is formed in a portion of the water channel from which the protrusion 57 has been removed.

The removal of the protrusion 57 facilitates the installation of the carry-in / out airlock 89 (see FIG. 31), which will be described later, without being disturbed by the protrusion 57. Therefore, by using the carry-in / out airlock 89, it is possible to easily secure a carry-out route into the radiation shielding container 32 of the reactor internal structure removed in the reactor pressure vessel 3.

A new side wall of the radiation shielding container 32 is installed (step S8C). There are two doors 64A, 64B moving between the work house 49 and the opening to form the opening 36B between the radiation shielding vessel 32 and the reactor well 25. Further, the opening 60A is also formed in the isolation wall 60 that divides the work house 49, which will be described later, by the two doors. The two doors 64A and 64B are set at the positions where the throttle plugs are removed, and are located at the dimensional discontinuity that is the boundary between the circular reactor well and the square equipment temporary storage pool 26. The width dimension of 64B is different. The door 64A has the width dimension of the isolation house 49, and the door 64B corresponds to the throttle plug installation width of the equipment temporary storage pool. As for the installation of the dimensional discontinuity portion, by removing the throttle plug first as described above, the installation of the two doors 64A and 64B serving as the partition of the boundary surface becomes easy. In FIG. 25, the door 64B moves to the uppermost position, and the door 64A moves to near the height of the radiation shielding plate 33 to form the opening 36B. This mechanism has the advantage of being able to form the openings required for the work to be performed. The doors 64A and 64B are sealed so that radioactive substances do not move between the rooms due to the movement.

The overhead crane installed in the isolation house is removed, and two overhead cranes and an isolation wall are newly installed in the isolation house (step S8D). The overhead crane 50 installed in the isolation house 49 is removed, and guide rails 51A and 51B are newly installed in the isolation house 49 near the ceiling of the isolation house 49. Then, the overhead cranes 50A and 50B are installed on the guide rails 51A and 51B (see FIG. 26). A traveling crane carried into the isolation house 49 is used for removing the overhead crane 50 and installing the overhead cranes 51A and 51B. After the overhead cranes 50A and 50B are installed, the isolation wall 60, in which the opening 60A is formed and the door for opening and closing the opening 60A is movably attached, is carried into the isolation house 49 and the radiation shielding container 32 is installed. It stands near the end of the reactor well 25 side and is attached to the inner surface of the isolation house 49 by welding (see FIG. 26).

By attaching the isolation wall 60, two spaces 53A and 53B are formed in the isolation house 49. The overhead crane 50A and the guide rail 51A are arranged in the space 53A formed directly above the reactor well 25, and the overhead crane 50B and the guide rail 51B are arranged in the space 53B formed directly above the radiation shielding container 32. Is placed. A grip 52A is attached to the wire 56A attached to the overhead crane 50A, and a grip 52B is attached to the wire 56B attached to the overhead crane 50B. The openable and closable isolation sheet 62 attached to the inner surface of the isolation house 49 is arranged closer to the space 53B than the door 61. A plate-shaped floor member 58 forming the bottom surface of the space 53A is attached to the lower end of the isolation house 49. The floor member 58 is formed with an opening 58A having the same size as the inner diameter of the reactor well 25.

A second radiation shield is installed (step S9). The radiation shield (second radiation shield) 59, which also serves as a platform, can be removed from the top of the stepped surface of the reactor well wall surface after removing the throttle plug 29A and the throttle plug 29B using the overhead crane 50A. (See FIG. 26). The platform 59 with a radioactive shield has a rail (not shown) moving in the circumferential direction on the lower surface, a drive carriage (not shown), and a suspension portion (not shown) on the lower surface of the drive carriage. By setting various work devices (for example, the first muscle robot 204, which will be described later) on the suspension portion from the storage pool side, subsequent cutting and handling work in the reactor well can be performed. In addition, the central part has a removable inner circle and an outer circle, and when conducting a survey inside the reactor pressure vessel, which will be described later, it is used for passing a drill that provides a through hole in the pressure vessel head. When removing the inner circle and setting the isolation vessel for removing the equipment inside the reactor pressure vessel, remove the outer circle and use it for passing through the isolation vessel. An openable and closable isolation sheet 54 housed in the isolation film storage container 73 is arranged so as to cover the platform 59 that also serves as a second radiation shield installed so as to cover the reactor well 25 after installation. The platform 59, which also serves as a second radiation shield, is transported by a crawler crane to the outside of the isolation house 49 on the driver's floor 24, and further to the space 53A via the space 53B. The platform 59, which also serves as a second radiation shield, is suspended from the overhead crane 50A and placed on the uppermost stage of the wall surface of the reactor well through the opening of the opening / closing isolation sheet 54, and is placed on the floor by the above-mentioned driving device. It is installed so as to cover the opening 58A of the member 58.

The equipment in the reactor well is removed and carried out (step S10). The removal and unloading of the equipment arranged in the reactor well 25, for example, the containment head 18 attached to the upper end of the reactor containment vessel 17 and arranged in the reactor well 25, is shown in FIGS. 26 and 27. Will be described using. First, in order to make it easy to remove the equipment in the reactor well, the shield bag 48 is carried out (see FIG. 26).

Carrying out the shield bag 48 is performed in the reverse step of carrying in the shield bag 48 described in step S5, except for carrying in and out of the shield transport device 47. In the shield transport device 47, another isolation chamber 40 in which the shield transport device 47 and the folded shield bag 48 are housed is placed in the radiation shield container 32 through the opening 36A as in the step S2. It is carried in and then the door 34 is closed. The isolation chamber 40 comes into contact with the protrusion on the reactor well 25 side of the radiation shielding container 32 and stops. The shield body transport device 47 has a slide mechanism 45B, a telescopic pipe 45A, and a work arm 45C attached to the upper end portion of the support member 42, similarly to the handrail removal device 45. The gripper 47A is attached to the tip of the work arm 45C.

The working arm 45C and the gripper 47A holding the shielding bag 48 are inserted into the reactor well 25. Then, a water supply hose (not shown) installed along the telescopic pipe 45A and the work arm 45C is extended and connected to the one-touch coupler provided in the shield bag 48 with the non-return function released, and is connected to the inside of the shield bag 48. Water is drained. After that, the expansion tube 45A and the working arm 45C are contracted to collect the shielding bag 48. This step is sequentially performed on the left and right shielding bags 48, and then the shielding bag 48 is carried out of the radiation shielding container 32 through the opening 36A.

Next, the steps of removing and carrying out the containment vessel head 18 will be described with reference to FIG. 27. First, the first muscle robot 204, which is an articulated manipulator, is carried into the reactor well 25.
The first muscle robot is carried into the space 37 in the radiation shielding container 32 by the isolation chamber 40 in the same manner as the shielding body conveying device 47. In the isolation chamber 40, the first muscle robot 204 is hung on the tip side having a step by the amount of elevation, the first muscle robot 204 is carried into the reactor well 25, and the first muscle robot 204 is moved up and down to be fitted into the swivel portion 79A. Has an arm. The swivel portion 79A has a function of orbiting the back surface of the second radiation shield on the reactor well 25 side.

The first muscle robot 204 includes a telescopic portion that changes the arm length, a posture portion that changes the tip posture three-dimensionally, a camera (not shown) provided at the tip of the posture portion, and a cutting device as a work effector. And have. Further, the first muscle robot 204 has a mounting portion 204A that fits with the swivel portion 79A, a wire is variably attached to the mounting portion 204A, and a gripper 72B is attached to the tip of the wire. Be done.

With this configuration, the operator grasps a convex portion such as a hook provided on the containment vessel head 18 by monitoring by a camera, operates the first muscle robot 204, and includes an arbitrary range including the hook. You can cut the range.

After installing the first muscle robot 204 in the reactor well 25, the isolation chamber 40 in which the cutting and recovery device 70 is housed, and the loading and unloading chamber 75 in which the storage container 206 capable of storing the shredded pieces are carried in and out. Are sequentially suspended by a crawler crane and carried into the space 37 of the radiation shielding container 32 through the opening 36A (see FIG. 27).

The cutting / recovery device 70 includes a slide-type stand 205 for collecting cut pieces of the containment vessel head cut to a predetermined size by the first muscle robot 204, and a second muscle robot 208 for further shredding the collected cut pieces. And a horizontal moving portion 209 that moves the second muscle robot left and right so that it can be efficiently shredded and collected in the storage container 206.

The slide type gantry 205 has a slide portion 205A that can be carried in and out of the reactor well 25 through the opening 70B provided at the position of the cutting recovery device 70 corresponding to the opening 36B of the radiation shielding container 32.
The second muscular robot 208 is provided at the telescopic portion provided on the root side for changing the arm length, two posture portions fixed to the telescopic portion that can be postured three-dimensionally, and the tip of each posture portion. It has a gripper and a cutting device (not shown) as a work effector.

The isolation chamber 40 and the carry-in / out chamber 75 each have an openable / closable opening (not shown) provided adjacent to each other, and for example, the storage container 206 has a moving means 206A that can move between the two through the opening. Further, the carry-in / out chamber 75 has an opening 75A that can be opened / closed at a position corresponding to the opening 36A of the radiation shielding container 32.

With these configurations, the cutting / recovering device 70 can further shred the cut piece 18A of the PCV head 18 collected by the slide portion 205A, grab the fine piece, and store it in the storage container 206. Then, the small pieces stored in the storage container 206 are transferred to the space 53B of the isolation house 49 by the overhead crane 50B through the opening 75A and the opening 36, and further transported on the operation floor 24 outside the isolation house 49. , Dropped on the ground.

The above procedure shows that the containment vessel head 18 is removed after installing the isolation house on the operating floor after removing the shield plug, but the containment vessel head 18 may be removed before removing the shield plug. At this time, the apparatus has the same structure as the decontamination apparatus 46 in the reactor well shown in FIG. 14, and has a slide mechanism 45B, a telescopic pipe 45A, and a working arm 45C attached to the upper end portion of the support member 42. Using this device, the containment vessel head 18 is cut into small pieces in the same manner as the removal of the handrail of the containment vessel head 18, and the cut pieces are drawn into the isolation chamber 40, stored in the storage container in the isolation chamber 40, and carried out. do. The storage container may be carried out by connecting the carry-in / out chamber 75 shown in FIG. 27. This method is the same for the heat insulating material described later.

As a method of carrying out the storage container 206, another method of preventing leakage of radioactive substances via the water storage chamber 301 will be described with reference to FIG. 42. The water storage chamber 301 has a partition in the center, and this partition has a passage on the lower surface through which the storage container 206 can pass. The water surface is located above the passage on the lower surface. The water storage chamber 301 has a carry-in port 302 and a carry-out port 303 of the storage container 206, and a lifting machine (not shown) is attached above the carry-in port 302, and the storage container 206 carried in from the carry-in port 302 is installed. It is possible to install it on the transportation means 206A provided below the surface of the water. The carry-in inlet 302 of the water storage chamber 301 is connected to the carry-out outlet of the storage container 206 of the isolation chamber 40 used as a shredding area, and the space between them is airtight with a seal structure. The carry-out port 303 of the water storage chamber 301 is located on the lower surface of the opening 34 of the radiation shielding container 32 installed in the equipment temporary storage pool. Next, the procedure for carrying out the storage container 206 will be described. The storage container 206 shredded and stored in the isolation chamber 40 is lifted by a lifting machine (not shown) arranged along the rail of the second muscle robot 208 located at the upper end of the isolation chamber 40. , Handed over to the lifting machine (not shown) on the water storage chamber 301 side.
After that, it is hung below the water surface, installed on the moving means 206A provided on the lower surface, passes through the passage provided on the surface, and moves to the carry-out port 303 side. An overhead crane 50B from the isolation house is placed above the carry-out port 303, and is lifted to the surface of the water and carried out. As a result, when the storage container 206 is carried out, the radioactive material existing in the isolation chamber 75 is suppressed from diffusing on the water surface, and it is possible to prevent the radioactive material from flowing out from the carry-out port 303 of the water storage chamber 301 into the radioactive shielding container 32.

Next, the heat insulating material 30 is removed and carried out (FIG. 28). The details are the same as the removal and unloading of the PCV head 18, and can be explained by paraphrasing the containment vessel head 18 with the heat insulating material 30, so detailed description thereof will be omitted. Reference numeral 4A is a cut piece of the heat insulating material 30.

The containment vessel head 18 and the heat insulating material 30 described above were taken out and carried out after the second radiation shield 59 was provided. On the other hand, the dismantling approach may be performed from the 32 side inside the radiation shielding container, or the first muscle robot may be configured more compactly, so that the shield plug 28 may be maintained. After that, the second radiation shield 59 may be installed for the subsequent work. As a method of carrying out the storage container 206, the above-mentioned water storage chamber 301 may be used in the same manner instead of the carry-in / out chamber 75.

From the above, the containment vessel head 18 and the heat insulating material 30 are contaminants, and in particular, the heat insulating material 30 has a complicated shape, so that decontamination is difficult and the heat insulating material 30 has a high radiation equivalent rate. Pulling these structures from the reactor well onto the working floor significantly worsens the working environment on the working floor and interferes with other parallel work. On the other hand, cutting and unloading the equipment in the reactor well and storing it in the unloading container with a shield and carrying it out in the reactor well and on the temporary storage pool side will increase the radiation equivalent rate on the operating floor and carry it out. It can be expected to prevent the diffusion of radioactive dust and maintain a working environment that workers can approach.

As a result, the removal and unloading of the equipment in the reactor well in step S10 is completed.
In FIG. 27, in addition to step S10 in which the equipment in the reactor well is removed and carried out, the spent fuel rod 203 is moved from the fuel storage pool 27 to, for example, a shared pool outside the reactor building 23 by the fuel extraction device 201. The pool fuel extraction step (step SF1) to be transferred is described. The spent fuel rod 203 is taken out from the fuel rack 202 by the expansion pipe 201B of the fuel take-out device 201, and is transferred to the common pool by the moving function of the main body 201A of the fuel take-out device.

The pool fuel removal step is performed not only at the time of taking out and carrying out the containment vessel head 18, but also in parallel with the opening work of the reactor pressure vessel for a long period of time, for example, one year from step S1 shown in FIG. Therefore , the overall work time can be significantly shortened as compared with the conventional method in which both operations are sequentially performed.

Next, the baffle plate 76 is removed, and the pressure vessel support and the radiation shield plate 79 are attached (step S11). When the pool fuel removal work is not completed, this step is carried out in parallel with the containment vessel head and heat insulating material removal. The reason for removing the baffle plate 76 is that the baffle plate 76 does not have the ability to support the pressure vessel 4. In consideration of future work in the pressure vessel 4, a support beam member 80 having a high support capacity is laid. Step S11 will be described with reference to FIG. 29.

In the step of step S11, the cutting / recovery device 70, the loading / unloading chamber 75, the storage container 206, and the like in the isolation chamber 40 used for removing and carrying out the equipment in the reactor well of step S10 are used.
As shown in FIG. 29, the radiation shielding plate 79 and the support beam member 80 are placed on the sliding pedestal 205 in the isolation chamber 40 via the loading / unloading chamber 75. After that, the door 64 in the isolation chamber 40 is opened, the slide portion 205A is carried into the nuclear well 25, the radiation shielding plate 79 is grasped by the gripper 72B, and the slide portion 205A is moved above the baffle plate 76 in the reactor well 25. Then, the radiation shielding plate 79 is placed on the baffle plate 76. The support beam member 80 in the isolation chamber 40 is also similarly gripped by the gripper 72B and placed on the baffle plate 76 as well. However, nothing is placed on the baffle plate 76 at one place, and only the radiation shielding plate 79 is placed on the baffle plate 76 adjacent to the baffle plate 76.

The baffle plate 76 on which nothing is placed is gripped by the gripper 72B and removed. Each of the removed baffle plates 76 is carried out via the isolation chamber 40 and the carry-in / out chamber 75. Next, the radiation shielding plate 79 on the adjacent baffle plate 76 is gripped by the gripper 72B and lowered to the region between the reactor pressure vessel 3 and the reactor containment vessel 17, and then the reactor pressure vessel 3 and It is attached to the reactor containment vessel 17. Next, the support beam member 80 installed on the baffle plate 76 adjacent to the baffle plate 76 on which nothing is placed is gripped by the gripper 72B and lowered, and the reactor is placed above the radiation shielding plate 79. It is installed in the pressure vessel 3 and the biological shield 100. The state at this time is the radiation shielding plate 79 and the support beam member 80 existing on the right side of FIG. 29. The above processing is performed on the baffle plate 76 on which nothing is placed one after another. Finally, the shortage of the radiation shielding plate 79 and the support beam member 80 are procured from the slide portion 205A. As a method of carrying out the storage container 206 or the like for storing the removed waste such as the baffle plate, the above-mentioned water storage chamber 301 may be similarly used instead of the carry-in / out chamber 75.

A plurality of radiation shielding plates 79 arranged in the region between the reactor pressure vessel 3 and the reactor containment vessel 17 and attached to the reactor pressure vessel 3 and the reactor containment vessel 17 are the reactor pressure vessel 3 and the reactor. The area between the containment vessels 17 is blocked to block the radiation from the reactor containment vessel 17 toward the reactor well 25, and further prevent the rise of radioactive dust from the reactor containment vessel 17 toward the reactor well 25. do. The plurality of support beam members 80 arranged in the region between the reactor pressure vessel 3 and the bioshield 100 and attached to the reactor pressure vessel 3 and the bioshield 100 are the reactor pressure vessel 3 and the bioshield 100. The area between them is closed, and the reactor pressure vessel 3 is supported from the biological shield 100. This is to prevent the reactor pressure vessel 3 from falling downward as a countermeasure in case the strength of the concrete support of the pedestal 15 supporting the reactor pressure vessel 3 is hindered.

The inside of the reactor containment vessel is investigated (step S11.5). When the pool fuel removal work is not completed, this step is carried out in parallel with the containment vessel head and heat insulating material removal. The investigation process for investigating the inside of the reactor containment vessel will be described with reference to FIG. In this investigation step, a through hole is made in the pressure vessel head 4, a camera is inserted through the through hole, and the state inside the reactor containment vessel is investigated. For that purpose, first, the head investigation jig 210 having the built-in drill 210A is transferred to the isolation chamber 40 through the carry-in / out chamber 75, and is carried into the reactor well 25 using the slide portion 205A of the slide type gantry 205. After that, it is installed on the head of the pressure vessel head 4 by using the first muscle robot 204 and the gripper 72B. The motor 210B is driven, and the drill tool 210A built in the inner cylinder on the tip side of the head investigation jig 210 is rotated while being extended, and a through hole 4B is formed in the pressure vessel head 4 as shown in FIG.

After that, the head investigation jig 210 is once returned to 49 of the isolation house, a camera is newly attached instead of the drill tool 210A, and the camera is installed again on the head of the pressure vessel head 4 in the same manner as in the case of the drill tool. The motor 210B is driven to insert the camera into the pressure vessel through the through hole 4B, and the state of the inside of the nuclear pressure vessel 3, particularly the vicinity of the pressure vessel head 4 and the steam dryer 12 is grasped. By grasping the state of the steam dryer 12, it can be reflected in the removal work of the steam dryer 12.

Further, if the state of the steam dryer 12 is solid, a through hole is made in the steam dryer 12 in the same manner, the state of the steam separator 11 is similarly grasped, and the steam dryer is taken out. Can be reflected.

An alternative method to the investigation process for investigating the inside of the reactor containment vessel will be described with reference to FIG. 43. In this investigation step, a through hole is made in the pressure vessel head 4, a camera is inserted through the through hole, and the state inside the reactor containment vessel is investigated. For that purpose, first, the head investigation jig 210 having a built-in drill 210A is housed in the investigation container 310 having a shield, and is set on the upper surface of the platform 59 also used as the second radiation shield through the isolation house 49. As a procedure at that time, the investigation container 310 is once installed on the upper surface of the isolation film 54, and after wrapping the investigation container 310 from below, it is set on the lower surface of the isolation film 54 by fusing and welding on the upper surface of the investigation container 310. After that, the inner circle portion located at the center of the platform 59 that also serves as the second radiation shield is removed by the working device (not shown) contained in the survey container 310, and the platform that also serves as the second radiation shield is placed on the lower surface of the survey device 310. A passage is formed through which the drill penetrating the 59 is passed. The motor 210B is driven, and the drill tool 210A built in the inner cylinder on the tip side of the head investigation jig 210 is rotated while being extended, and a through hole 4B is formed in the pressure vessel head 4 as shown in FIG. 43.

After that, the head investigation jig 210 is once returned to the investigation container 310, a camera is newly attached instead of the drill tool 210A, and the head investigation jig 210 is installed on the head of the pressure vessel head 4 again in the same manner as in the case of the drill tool. The motor 210B is driven to insert the camera into the pressure vessel through the through hole 4B, and the state of the inside of the nuclear pressure vessel 3, particularly the vicinity of the pressure vessel head 4 and the steam dryer 12 is grasped. By grasping the state of the steam dryer 12, it can be reflected in the removal work of the steam dryer 12.
As a survey method, the head survey jig is hung down by the elevating device 83, a through hole is provided in the pressure vessel head 4, and the inside of the pressure vessel head 4 is surveyed by a camera in the state of the isolation vessel described with reference to FIG. You may.

An isolation container is installed (step S12). After the step of step S11 is completed, the isolation vessel 81 is arranged from the reactor well 25 over the space 53A (see FIG. 31). The configuration of the isolation container 81 will be described with reference to FIG. The isolation container 81 has an upper cylindrical member 81A, an intermediate cylindrical member 81B, and a lower cylindrical member 81C, and the upper end of the upper cylindrical member 81A is sealed by a cover member 81D which is a disk. The lower cylindrical member 81C in which the shielding bag 86 is installed is installed on the support beam member 80 in the reactor well 25. An intermediate cylindrical member 81B having a shielding bag 85 installed inside is placed at the upper end of the lower cylindrical member 81C and is coupled to the lower cylindrical member 81C. The upper cylindrical member 81A sealed by the cover member 81D on which the holding member 82 and the supporting member 82A are arranged is placed at the upper end of the intermediate cylindrical member 81B and coupled to the intermediate cylindrical member 81B. A radiation shield plate 91 having an opening through which the intermediate cylindrical member 81B passes is installed on the floor member 58, and the radiation shield plate 91 has an opening 58A formed in the floor member 58 except for the portion of the intermediate cylindrical member 81B. Covering. The intermediate portion of the second radiation shield 59 has a diameter slightly wider than the outer diameter of the opening 58A.

Further, the carry-in / out airlock 89 is arranged in the reactor well 25, and one end of the carry-in / out airlock 89 is attached to the side wall 63 of the radiation shielding container 32. An opening / closing door 89A is attached to one end of the carry-in / out airlock 89 on the radiation shielding container 32 side. The other end of the carry-in / out airlock 89 is attached to the lower cylindrical member 81C. An opening / closing door 89B is attached to the other end of the carry-in / out airlock 89 on the lower cylindrical member 81C side. The space 89C in the carry-in / out airlock 89 is connected to the inside of the radiation shielding container 32 by opening the opening / closing door 89A, and is connected to the inside of the lower cylindrical member 81C by opening the opening / closing door 89B.

The carry-in / out airlock 90 is arranged on the radiation shielding plate 91 in the space 53A, and one end of the carry-in / out airlock 90 is attached to the intermediate cylindrical member 81B. An opening / closing door 90A is attached to one end of the carry-in / out airlock 90 on the intermediate cylindrical member 81B side. An opening / closing door 89B is attached to the other end of the carry-in / out airlock 90. The space 90C in the carry-in / out airlock 90 is connected to the inside of the intermediate cylindrical member 81B by opening the opening / closing door 90A, and is connected to the space 53A in the isolation house 49 by opening the opening / closing door 90B.

A watering device (not shown) is installed near the top of the inner surface of the carry-in / out airlock 89, and a watering device (not shown) is installed near the top of the inner surface of the carry-in / out airlock 90. Further, an air replacement device (not shown) for replacing the air in the space 89C is installed in the carry-in / out airlock 89, and an air replacement device (not shown) for replacing the air in the space 90C is also installed in the carry-in / out airlock 90. Is installed.

The upper cylindrical member 81A, the intermediate cylindrical member 81B, and the lower cylindrical member 81C sealed by the cover member 81D are combined as described above, and further, the opening / closing door 89A of the carry-in / out airlock 89 and the opening / closing door 90A of the carry-in / out airlock 90 are further connected. A sealed space 93 is formed in the isolation container 81 formed by connecting the upper cylindrical member 81A, the intermediate cylindrical member 81B, and the lower cylindrical member 81C.

Each of the intermediate cylindrical member 81B and the lower cylindrical member 81C is carried into the reactor well 25 and the space 53A in a state where the shielding bags 85 and 86 are not filled with water. Since the shielding bags 85 and 86 are not filled with water, the intermediate cylindrical member 81B and the lower cylindrical member 81C become lighter, and the intermediate cylindrical member 81B and the lower cylindrical member 81C can be easily carried into the reactor well 25 and the space 53A. Is. Water is supplied into the shield bags 85 and 86 by using a water supply hose connected to a make-up water system existing outside the isolation house 49 after the isolation vessel 81 is assembled in the reactor well 25 and the space 53A. Is done. Each of the shield bags 85 and 86 filled with water is a radiation shield. The shielding bag 85 filled with water is arranged so as to face the opening / closing door 90A of the air lock 90 for loading and unloading in the isolation container 81, and the shielding bag 86 filled with water is carried out in the isolation container 81. It is arranged so as to face the opening / closing door 89B of the incoming airlock 89 and cover the pressure vessel head 4. Similar to the shield bag 48, through holes 85A and 86A are formed in each of the shield bags 85 and 86 filled with water, respectively. The through hole 85A is surrounded by a member of the shielding bag 85, and the water in the shielding bag 85 does not flow out into the through hole 85A. The through hole 85A is closed by a shield bag 85 filled with water and expanded. The through hole 86A of the shielding bag 86 has a similar structure.

The rod-shaped support member 82A is arranged in the horizontal direction and attached to the inner surface of the upper cylindrical member 81A. The holding member 82 is installed on the support member 82A. The isolation sheet 84 is attached to the lower end of the upper cylindrical member 81A to isolate the space in the upper cylindrical member 81A from the space in the intermediate cylindrical member 81B. The elevating device (for example, a hoist) 83 is held by the wire 128 on the holding member 82. The wire 128 penetrates the isolation sheet 84, and the wire 128 and the isolation sheet 84 are sealed to maintain airtightness. This isolation sheet is folded into a bellows shape and has a structure that can be expanded and contracted as the wire descends and rises.

The pressure vessel head is removed (step S13). Since the pressure vessel head 4 is attached to the flange of the reactor pressure vessel 3 by a plurality of bolts, it is necessary to remove those bolts in order to remove the pressure vessel head 4 from the reactor pressure vessel 3. The outline of the removal of those bolts will be described. A Statvolt tensioner is used to remove these bolts. Although not shown, an isolation chamber 40 containing a stat bolt tensioner, a pair of half-split guide rails and a manipulator device (not shown) opens and closes through an opening 36A and a space 37 within a radiation shielding vessel 32. By opening the door 89A, the material is carried into the space 89C inside the carry-in / out airlock 89. At this time, the opening / closing door 89B is closed. The manipulator device has substantially the same configuration as the shield transfer device 47 used in step S5. The manipulator device includes a slide mechanism 45B, a telescopic tube 45A, and an articulated work arm 45C attached to the upper end of the support member 42. The gripper 47A is attached to the tip of the work arm 45C.

After grasping one of the guide rails in the isolation chamber 40 with the gripping tool 47A, the opening / closing door 89B is opened, and the slide mechanism 45B and the telescopic tube 45A are filled with water in the lower cylindrical member 81C. Moved downwards. The work arm 45C is bent and extended, and the half-split guide rail gripped by the gripper 47A is placed below the shielding bag 86 and above the flange of the pressure vessel head 4 to the inner surface of the lower cylindrical member 81C and the pressure vessel. It is arranged between the outer surfaces of the head 4 and at a position 180 ° opposite to the opening / closing door 89B. A plurality of support members are attached to the lower surface of the half-split guide rail, and the guide rail is supported on the support beam member 80 by these support members. The other half guide rail is also arranged by the manipulator device below the shielding bag 86 between the inner surface of the lower cylindrical member 81C and the outer surface of the pressure vessel head 4 at a position on the opening / closing door 89B side. The two half guide rails are connected to each other. Using the manipulator device, the guide rail is fitted with a moving device having a holding portion for the statvolt tensioner, to which the statvolt tensioner is mounted. By driving the moving device, the stat bolt tensioner is transferred above the bolt connecting the pressure vessel head 4 and the reactor pressure vessel 3, and this bolt is removed by the stat bolt tensioner. In this way, the bolts connecting the pressure vessel head 4 and the reactor pressure vessel 3 are sequentially removed. Then, the connection between the pressure vessel head 4 and the reactor pressure vessel 3 is released. Each removed bolt is collected in the isolation chamber 40 by a manipulator device. After that, the slide mechanism 45B and the telescopic tube 45A are contracted, and the gripper 47A is also housed in the isolation chamber 40.

The opening / closing door 89B is closed, and the door provided in the isolation chamber 40 is also closed. The air replacement device of the carry-in / out airlock 89 discharges the air in the space 89C to the outside and supplies the clean air from the outside into the space 89C. The air replacement device includes a purification device, and the radioactive substances contained in the air discharged from the space 89C are removed by the purification device. Water is poured from the watering device in the carry-in / out airlock 90 to the isolation chamber 40 to wash away the adhering radioactive substances. This water is discharged to a drainage device provided in the carry-in / out airlock 89. Then, the isolation chamber 40 is transferred to the space 37 in the radiation shielding container 32 by opening the opening / closing door 89A, closed the opening / closing door 89A, and then transported to the outside of the isolation house 49 through the opening 36A or the like.

While removing the bolt connecting the pressure vessel head 4 and the reactor pressure vessel 3, a gripper (not shown) is attached to the tip of the wire 87 wound around the lifting device 83. The wire 87 reaches the vicinity of the top of the pressure vessel head 4 through the through hole 85A of the water-filled bag 85 and the through hole 86A of the water-filled bag 86, and is attached to the wire 87. The tool grips the hanger 88 attached to the top of the pressure vessel head 4.

After the connection between the pressure vessel head 4 and the reactor pressure vessel 3 is released, the elevating device 83 is driven to wind the wire 87, so that the pressure vessel head 4 rises and the shield bag 86 filled with water is filled. It is inserted into the through hole 86A of the (see FIG. 32). As the pressure vessel head 4 rises in the through hole 86A, the water existing above the pressure vessel head 4 in the shield bag 86 moves below the pressure vessel head 4 in the shield bag 86. Therefore, the pressure vessel head 4 can easily rise in the through hole 86A of the shield bag 86 filled with water, and the position of the lower end of the shield bag 86 descends to the vicinity of the upper end of the steam dryer 12. The water-filled shielding bag 86 shields radiation from the inside of the reactor pressure vessel 3 below the steam dryer 12.

When the pressure vessel head 4 is filled with water in the sealed space 93 and rises between the shielding bag 85 and the shielding bag 86, the decontamination of the inner surface (lower surface) of the pressure vessel head 4 is performed by the decontamination device. It is carried out by 71 (see FIG. 33). The decontamination device 71 has a telescopic tube and a working arm like the shield transfer device 47, and has an injection nozzle at the tip thereof instead of the gripping tool 47A (see FIG. 16). Similar to the shield transport device 47, the isolation chamber 40 accommodating the decontamination device 71 is carried into the radiation shielding container 32 through the opening 36A, and further, the opening / closing door 89A is opened to enter the carry-in / out airlock 89. It is moved into the space 89C of. The opening / closing door 89A is closed, and the upper end portion which is a part of the opening / closing door 89B is opened. In the decontamination device 71, an expansion tube is inserted between the pressure vessel head 4 and the shielding bag 86 in the space 93. The work arm is operated to make the injection nozzle face the inner surface of the pressure vessel head 4, and water is injected from the injection nozzle. The inner surface of the pressure vessel head 4 is decontaminated by operating the expansion tube and the working arm while injecting water from the injection nozzle (see FIG. 33). The water that hits the inner surface of the pressure vessel head 4 and falls is received by a washing water tray (not shown) attached to the work arm, and is collected in a drain tank in the isolation chamber 40 as described above. The decontamination of the pressure vessel head 4 may be performed on the lower surface of the shielding bag 86. In this case, when the lower surface of the pressure vessel head 4 is pulled above the upper end of the dryer 12 in consideration of the space where the decontamination device 71 can be inserted, a work arm is set on the lower surface and decontamination is performed by the injection nozzle. do. After that, it passes through the shield bag 86 and is pulled up. After the decontamination of the inner surface of the pressure vessel head 4 is completed, the expansion tube, the working arm and the injection nozzle are housed in the isolation chamber 40, and the opening / closing door 89B is completely closed. The isolation chamber 40 is transported to the ground from the space 89C in the carry-in / out airlock 89 through the opening 36A.

A part of the water in the shield bag 85 is discharged to reduce the thickness of the shield bag 85 in a state where water is present inside. The elevating device 83 is driven to raise the pressure vessel head 4 to a position facing the opening / closing door 90A (see FIG. 34). After that, the opening / closing door 90A is opened, the pressure vessel head 4 is transferred into the space 89C, and the opening / closing door 89A is closed. By opening the opening / closing door 90A, radioactive material may flow into the space 89C. Therefore, the air replacement device of the carry-in / out airlock 90 discharges the air in the space 90C to the outside and supplies the clean air from the outside into the space 90C. The air replacement device includes a purification device, and the radioactive substances contained in the air discharged from the space 90C are removed by the purification device. The pressure vessel head 4 is decontaminated before being carried into the space 90C, but after being carried into the space 90C, water is sprinkled on the pressure vessel head 4 again from the sprinkler device in the carry-in / out airlock 90 and adhered. Rinse away any radioactive material. This water is discharged to a drainage device provided in the carry-in / out airlock 90. Then, the opening / closing door 90B is opened to transfer the pressure vessel head 4 into the space 53A, and the pressure vessel head 4 is stored in a predetermined storage location. The opening / closing door 90B is closed.

The space 53A of the nuclear reactor well 25 and the isolation house 49, the pressure vessel head 4 arranged isolation container 81 so as to cover the pressure vessel head 4 removal by reactor opening the interior volume of small isolation container 81 of Even if the radioactive material is released from the reactor pressure vessel 3 from which the pressure vessel head 4 has been removed, the area contaminated by the radioactive material is limited to the isolation vessel 81, and a large volume atom is used. It is possible to prevent the inside of the reactor well 25 and the isolation house 49 from being contaminated by the radioactive substance.

Since the shielding bags 85 and 86 filled with water are arranged in the isolation vessel 81, the radiation radiated from the reactor pressure vessel 3 can be shielded by the shielding bags 85 and 86. Therefore, the dose in the isolation house 49, for example, the dose in the space 53A can be suppressed to a low value without being affected by the radiation from the reactor pressure vessel 3. The exposure of workers working in space 53A can be significantly reduced.

Since the equipment inside the isolation container 81 (for example, the pressure vessel head 4 or the like) is carried out of the isolation container 81 and the article is carried into the isolation container 81 through the carry-in / out airlocks 89 and 90, the isolation container is used. It is possible to prevent the release of the air containing the radioactive substance in 81 to the external environment. In particular, since each of the carry-in / out airlocks 89 and 90 is provided with a watering device and an air replacement device, it is possible to prevent the release of radioactive substances into the external environment.

Further, as another method of taking out the pressure vessel head 4, there is also a method of shredding before setting the isolation vessel 81 as in the case of removing the containment vessel head 18. FIG. 44 shows a state when the pressure vessel head 4 is shredded. The details are the same as the removal and unloading of the PCV head 18, and can be explained by paraphrasing the containment vessel head 18 to the pressure vessel head 4, so detailed description thereof will be omitted. Reference numeral 4A is a cut piece of the pressure vessel head 4. As a method of carrying out the storage container 206, the above-mentioned water storage chamber 301 may be used in the same manner instead of the carry-in / out chamber 75.

As described above, the reactor opening work in the method of opening the reactor pressure vessel is completed, and all the steps of the method of opening the reactor pressure vessel are completed.

Taking out the steam dryer and the steam separator will be described. After the removal of the pressure vessel head 4 (step S13) is completed, the steam dryer and the steam separator are taken out (step S14). First, the removal of the steam dryer 12 when the steam dryer 12 can be easily removed from the reactor pressure vessel 3 will be described below with reference to FIGS. 35 to 37.

Although not shown in FIG. 35, the isolation chamber 40 accommodating the manipulator device used in step S13 and the suspension balance 92 is carried into the space 37 in the radiation shielding container 32 through the opening 36A, and further opened and closed. Open the door 89A and transfer it into the carry-in / out airlock 89. After the isolation chamber 40 is transferred into the carry-in / out airlock 89, the opening / closing door 89A is closed and the opening / closing door 89B is opened. The suspension balance 92 in the isolation chamber 40 is grasped by the gripping tool 47A of the manipulator device, and then the slide mechanism 45B and the telescopic tube 45A are extended to carry the suspension balance 92 into the space 93 in the isolation container 81. After placing the suspension balance 92 on the steam dryer 12, the gripping tool 47A is separated from the suspension balance 92, and the gripping tool 47A grips and lifts the suspending tool of the suspension balance 92. A gripper attached to a wire 87 connected to the lifting device 83 grips the suspender of the suspension balance 92.

After the work arm 45C and gripper 47A of the manipulator device are housed in the isolation chamber 40, the open / close door 89B is closed, the air in the space 89C is replaced with clean air by the air replacement device, and the carry-in / out airlock. The water jetted from the sprinkler in 89 is hung on the outer surface of the isolation chamber 40 to wash away the adhering radionuclides. The opening / closing door 89A is opened, the isolation chamber 40 is transferred to the space 37, and the opening / closing door 39A is closed.
The isolation chamber 40 is transported to the ground through the opening 36A.

After the steam dryer 12 is removed from the reactor pressure vessel 3, the lifting device 83 is driven to wind the wire 87 (see FIG. 35). Further, when the wire 87 is wound up, the steam dryer 12 rises. When the lower end of the steam dryer 12 rises to the position of the carry-in / out airlock 89, the rise of the steam dryer 12 is stopped and the opening / closing doors 89A and 89B are opened. The sliding carriage 92, which has been carried into the radiation shielding container 32 and placed on the bottom surface of the radiation shielding container 32, is moved into the lower cylindrical member 81C through the carry-in / out airlock 89. By driving the elevating device 83 and rewinding the wire 87, the steam dryer 12 is placed on the sliding carriage 92 in the lower cylindrical member 81C (see FIG. 36). Since the opening / closing doors 89A and 89B are open, the radionuclides in the lower cylindrical member 81C may diffuse into the carry-in / out airlock 89 and the radiation shielding container 32.

By moving the sliding carriage 92, the steam dryer 12 is transferred through the carry-in / out airlock 89 to the space 37 in the radiation shielding container 32 (see FIG. 36). The opening / closing doors 89A and 89B are closed. As described above, the air in the space 89C in the carry-in / out airlock 89 is replaced, and the inside of the carry-in / out airlock 89 is washed by sprinkling water. A watering device (not shown) is installed on the lower surface of the radiation shielding plate 33 in the radiation shielding container 32, and an air replacement device (not shown) is installed on the radiation shielding plate 33. After the steam dryer 12 is transferred to the space 37 in the radiation shielding container 32 and the opening / closing doors 89A and 89B are closed, the air in the radiation shielding container 32 is replaced with clean air by the air replacement device, and the air in the radiation shielding container 32 is replaced with clean air from the sprinkler. The steam dryer 12 and the sliding trolley 92 of the radiation shielding container 32 are washed by the jetted water. The steam dryer 12 and the sliding carriage 92 of the radiation shielding container 32 are transported to the ground through the opening 36A.

The air-water separator 11 attached to the core shroud 6 in the reactor pressure vessel 3 is also taken out from the reactor pressure vessel 3 and transported to the ground through the opening 36A in the same manner as the steam dryer 12.

As a countermeasure after taking out the steam dryer 12, there is also a means of shredding in the space inside the radioactive shielding container 32 installed in the equipment temporary storage pool. The shredding procedure of the steam dryer 12 will be described with reference to FIG.
The steam dryer 12 is shredded remotely in water to reduce radiation and prevent the diffusion of radioactive dust generated during cutting. In that case, the radiation shielding container 32 arranged in the equipment temporary storage pool is modified before the steam dryer 12 is taken out. A movable underwater work arm 321 is attached to the entire surface of the radioactive shielding container 32 for newly performing shredding work on the lower surface of the radioactive shielding container 32. Next, the carry-in / out airlock 89A of the radiation shielding container 32 is removed, a new partition 322 is attached to the upper surface of the radiation shielding container 32, and then a new opening / closing device 323 is attached to the upper opening. The steam dryer 12 and the air-water separator 11 are removed from the reactor pressure vessel in the same manner as in the procedure shown in FIG. 35, and are sequentially carried into the newly modified radiation shielding vessel 32 by a pull-in device 320 having a conveyor function. do. After that, water is filled in the radiation shielding container 32, and shredding is performed remotely underwater. The shredding work is cut and handled by the underwater work arm 321 and stored in the storage container 206. The storage container 206 has a moving means 206A on the lower surface, moves through the passage on the lower surface of the partition 322, and is located at the carry-out port. After that, it is pulled up to the surface of the water by an overhead crane 50B and carried out. At this time, the height of the water surface of the radiation shielding container 32 is set higher than the lower end of the partition 322, so that dust containing radioactive substances generated at the shredded place is prevented from diffusing by the partition 322, and the carry-out port of the radiation shielding container Prevent outflow to the side. This idea is the same as that of the water storage chamber 301 shown in FIG. 42. The dust containing radioactive substances generated at the shredded place is ventilated by a ventilation device (not shown) connected to the radiation shielding container 32 and collected by a filter (not shown). Further, the suspended particles and sedimented particles extracted into water are similarly purified by a water purification device (not shown) with a filter connected to the radiation shielding container 32.
Since the above-mentioned shredding work of the steam generator 12 and the steam separator 11 is carried out in the equipment temporary storage pool, the fuel debris extraction work is performed in parallel without causing interference with the work on the reactor pressure vessel side. Can be carried out.

If the steam dryer 12 cannot be removed from the reactor pressure vessel 3 when the steam dryer 12 is taken out, the steam dryer 12 shown in FIG. 38 can be used as an alternative to the above-mentioned removal of the steam dryer 12. Removal is carried out. The steam dryer 12 is taken out as a cut piece by cutting the steam dryer 12. The alternative will be described with reference to FIG. 38.

The dismantling device 94 is carried into the lower cylindrical member 81C from the space 37 in the radiation shielding container 32 through the carry-in / out airlock 89. The door 34 of the radiation shielding container 32 is closed. The manipulator device described above is used for this delivery. The dismantling device 94 is suspended from a gripper of the elevating device 83 and installed on the upper flange of the reactor pressure vessel 3.

The configuration of the dismantling device 94 will be described below. The dismantling device 94 has four columns 94B, which are connected by each of the four horizontally arranged connecting members 94A. The articulated arm 94C provided with a cutting machine 94D at the tip and the articulated arm 94E provided with a gripping tool 94F at the tip are movably attached to a connecting member 94A extending in the horizontal direction. It is attached to the mobile trolley. The four columns 94B are installed on the upper flange of the reactor pressure vessel 3.

Further, the storage container transport device 95 is carried in from the space 37 in the radiation shielding container 32 to the space 89C in the carry-in / out airlock 89. The storage container transport device 95 includes a storage unit 95E that also serves as a support member, a pair of support members 95B that are attached to a horizontal member (not shown) attached to the upper end of the storage unit 95E across the storage unit 95E, and It has a guide arm 95A that is attached to the upper end of these support members 95B and extends in the horizontal direction. The suspension device 95C is attached to the guide arm 95A so as to be movable along the guide arm 95A. The wire 95D is attached to the suspension device 95C, and a hanger (not shown) is attached to the wire 95D.

In the dismantling device 94, the cut portion of the steam dryer 12 is grasped by using the gripping tool 94F at the tip of the arm 94E attached to the moving carriage moving along the connecting member 94A, and the arm 94C attached to the moving carriage. The cut portion is cut using the cutting machine 94D at the tip of the above. The cut piece of the steam dryer 12 gripped by the gripper 94F is suspended by the suspension device 95 that moves along the guide arm 95A of the storage container transport device 95 by the operation of the arm 94E, and is inside the lower cylindrical member 81C. It is stored in the storage container 96 located in. The cut pieces of the steam dryer 12 that are sequentially generated by cutting by the cutting machine 94D are grasped by the gripping tool 94F and sequentially stored in the storage container 96 suspended by the hanging device 95.

When the storage container 96 is filled with those cut pieces, the hanging device 95 moves directly above the storage unit 95E and suspends the storage container 96 suspended in the storage unit 95E, and the storage unit 95E is suspended. Store inside. When a predetermined number of storage containers 96 in which the cut pieces of the steam dryer 12 are stored are stored in the storage unit 95E, the opening / closing door 89A is opened and the storage container transport device 95 shields radiation from the carry-in / out airlock 89. It is moved to the space 37 in the container 32. Using the suspension device 95C, all the storage containers 96 in the storage unit 95E are sequentially transferred into a plurality of transport containers (not shown) placed on the bottom surface of the radiation shielding container 32. When the storage container 96 in the storage unit 95E is exhausted, the storage container transport device 95 is moved into the carry-in / out airlock 89 again. The steam dryer 12 is cut in the lower cylindrical member 81C, the cut pieces are stored in the storage container 96 suspended by the suspension device 95C, and the storage container 96 is stored in the storage unit 95E. .. Then, the storage container 96 in which the cut pieces are stored is stored in the transport container in the radiation shielding container 32. Such a series of operations is performed until the cutting of the steam dryer 12 is completed. The transport container cleaned by the watering device in the radiation shielding container 32 is transported to the outside through the opening 36A.

After the steam dryer 12 has been cut and carried out, the steam dryer 94 and the storage container transport device 95 cut and carry out the steam separator 11 in the reactor pressure vessel 3 in the same manner as the steam dryer 12.

The reactor internal structure and fuel debris in the reactor pressure vessel are cut (step S15). As shown in FIG. 39, the core shroud 6, the core support plate 9, the upper lattice plate 10, the control rod guide pipe 13, and other core structures existing in the reactor pressure vessel 3 are cut. It is cut by the device 99.

The support member 131 is attached to the inner surface of the intermediate cylindrical member 81B below the water-filled shield bag 85, and a pair of winding devices 97A and 97B are installed on the upper surface of the support member 96. The wire 98A wound on the winding device 97A and the wire 98B wound on the winding device 97B are attached to the upper ends of the main body 99A of the cutting device 99, respectively. The cutting device 99 arranged in the reactor pressure vessel 3 is supported by wires 98A and 98B. The cutting device 99 and the support member 131 are taken in and out of the reactor pressure vessel 3 through the carry-in / out airlock 89.

The configuration of the cutting device 99 will be described with reference to FIGS. 40 and 41. The cutting device 99 has a main body 99A, a rotating body 99B to which a plurality of cutting blades 99C are attached to the lower surface, and a fishing head 99D. A rotating body 99B connected to a motor (not shown) installed in the main body 99A is rotatably attached to the main body 99A. A groove 99E that is opened downward is formed in the rotating body 99B so as to pass through the rotation center of the rotating body 99B. The fishing head 99D is attached to a moving table 99I arranged in the groove 99E and movably movable in the radial direction and attached to the rotating body 99B. Although not shown, the moving table 99I is provided with a rotating mechanism for rotating the hanging head 99D and a moving mechanism for moving the hanging head 99D in the rotation axis direction of the rotating body 99B. An injection nozzle 99F and a laser head 99G for a water jet or an abstract water jet are attached to the lower surface of the fishing head 99D.

The rotating body 99B of the cutting device 99 is rotated in the reactor pressure vessel 3, and each of the above-mentioned in-core structures is cut by a plurality of cutting blades 99C. The cutting of the internal structure is carried out while driving the winding devices 97A and 97B to rewind the wires 98A and 98B, respectively, and lowering the cutting device 99. When cutting the structure inside the furnace with the cutting blade 99C, the fishing head 99D exists in the groove 99E so as to be located above the lower surface of the rotating body 99B.

When the cutting device 99 advances the cutting of the internal structure in the reactor pressure vessel 3, the cutting device 99 approaches the lower mirror unit 5. Eventually, the fuel debris 39A existing in the vicinity of the lower mirror portion 5 in the reactor pressure vessel 3 begins to be cut by the cutting device 99. A mixture of a substance similar to ceramic and a metal melt exists on the surface of the fuel debris 39A, and the high altitude of this mixture makes it difficult to cut with the cutting blade 99C of the cutting device 99. Therefore, instead of the cutting blade 99C, the fuel debris 39A is pulled from the surface by using either the injection nozzle 99F or the laser head 99G provided on the fishing head 99D. When an injection nozzle 99F for a water jet or an aggressive water jet is used, the water jet or the absolute water jet is injected from the injection nozzle 99F toward the fuel debris 39A, and the fuel debris 39A is suspended by the water jet or the absolute water jet. .. When the laser head 99G is used, the surface of the fuel debris 39A is irradiated with a laser from the laser head 99G and the surface of the fuel debris 39A is hung.

In order to efficiently lift the fuel debris 39A by the injection nozzle 99F or the laser head 99G, the fishing head 99D is moved in the rotation axis direction of the rotating body 99B so that the water jet or the aggressive water jet or the laser does not hit the cutting blade 99C. It is moved to the cutting blade 99C side so that the injection nozzle 99F or the laser head 99G comes out ahead of the cutting blade 99C. In such a state, the fuel debris 39A of the water jet or the abstract water jet is injected or the fuel debris 39A of the laser is irradiated. The injection of the water jet or the abstract water jet or the irradiation of the laser is performed while rotating the fishing head 99D.

By slowly rotating the rotating body 99B while moving the fishing head 99D in the longitudinal direction of the groove 99E, the fuel debris 39A by the injection nozzle 99F or the laser head 99G can be used at any position in the radial and circumferential directions of the reactor pressure vessel 3. The structure inside the reactor and the cut pieces of the fuel debris 39A generated by cutting with the cutting device 99 capable of chipping are carried out of the reactor pressure vessel 3 (step S16). For the cutting piece, for example, a cavity is provided in the center of the cutting device 99, and the cutting piece is sucked from the cavity by a suction device provided in the radiation shielding container 32 and stored in the storage container. This storage container is transferred to a predetermined area in the radioactive waste treatment building and stored.
After the cutting of the reactor internal structure in the reactor pressure vessel 3 by the cutting device 99 is started, the cutting and the unloading are substantially performed in parallel.

The processing time can be shortened by cutting and carrying out the furnace structure and the fuel debris 39 described above.

The above-mentioned method of opening the reactor pressure vessel and the method of extracting fuel debris can be summarized as follows.
The first object of the above-mentioned method of opening the reactor pressure vessel is to provide a method of opening the reactor pressure vessel and carrying out the spent fuel unloading work in parallel.
Another object of the above-mentioned method of opening the reactor pressure vessel is to provide a method of opening the reactor pressure vessel capable of reducing the risk of exposure.
The feature to achieve the first purpose mentioned above is that the reactor wells connected to the equipment temporary storage pool and the equipment temporary storage pool are formed on the cab of the reactor building, and the reactor wells are covered with a shield plug. , The passage connecting the temporary storage pool of equipment and the reactor well is blocked by a throttle plug, and the reactor containment vessel is placed inside the reactor building. The reactor pressure placed in the reactor containment vessel in the nuclear plant. It is a method of opening the vessel, and is to secure a work space where the work of opening the reactor pressure vessel can be performed in parallel with the work of removing used fuel from the fuel storage pool.
It is possible to shorten the time required for the entire series of operations from the removal of falling objects to the removal of fuel debris.
Another feature that achieves the first and second objectives described above is that the reactor wells connected to the equipment temporary storage pool and the equipment temporary storage pool are formed on the cab of the reactor building, and the reactor wells are shield plugs. The passage connecting the temporary equipment pool and the reactor well is blocked by a throttle plug, and the reactor containment vessel is placed inside the reactor building. It is a method of opening the reactor pressure vessel to be used.
Establish an isolated area in the equipment temporary storage pool in consideration of airtightness and shielding.
A first through hole is formed in the throttle plug from the isolated area in the equipment temporary storage pool,
A platform for dismantling work, which also serves as a second radiation shield, was installed above the reactor well.
The purpose is to dismantle the equipment in the reactor well through the first through hole and carry it out of the equipment temporary storage pool.
An isolation area will be created in the equipment temporary storage pool on the opposite side of the fuel storage pool and the reactor well, and the equipment in the reactor well will be carried out through the isolation area to open the reactor pressure vessel. By performing the work of removing the fuel rods from the upper part of the fuel storage pool and the upper part of the temporary storage pool of equipment on the opposite side via the reactor well, the work of opening the reactor pressure vessel is parallel to the work of removing used fuel from the fuel storage pool. You can secure a work area that can be done.
In addition, since radiation from below the containment vessel head can be shielded by a platform for dismantling work that also serves as a second radiation shield, prevention of diffusion of radioactive dust from the inside of the reactor well and reduction of dose are temporary equipment. It will be handled in an isolated area installed in the containment pool, and it will be possible to prevent the diffusion of radioactive dust and the leakage of radiation on the operating floor of the reactor building.
Another feature that achieves the second purpose described above is that all the equipment in the reactor well that covers the pressure vessel head attached to the reactor pressure vessel is disassembled, carried out of the radiation shielding vessel, and then the pressure vessel. A second through hole is made in the head, a camera is inserted through the second through hole, the inside of the pressure vessel head is inspected, and then the equipment inside the nuclear pressure vessel is carried out to the outside of the reactor erection.
Since the state inside the reactor pressure vessel can be grasped in advance, it is possible to shorten the time required for carrying out the equipment inside the reactor pressure vessel, and it is possible to prevent the radiation duct and the dose from leaking.
In addition, leakage of radioactive materials from the reactor building can be prevented by installing a cover on the entire reactor building and controlling negative pressure, and this cover can be used for removing fallen objects from the reactor building. By using this in combination, it is possible to standardize the cover on the operating floor of the reactor building in each work step of removing fallen objects, taking out spent fuel, and taking out fuel debris.
In addition, the technical ideas of the method of opening the reactor pressure vessel and the method of extracting fuel debris described above are further summarized as follows.
(1) The equipment temporary storage pool and the reactor well connected to the equipment temporary storage pool are formed on the operating floor of the reactor building, and the reactor well is covered with a shield plug to form the equipment temporary storage pool. The passage connecting the reactor wells is blocked by a throttle plug, and the reactor containment vessel is arranged in the reactor building. It is arranged in the reactor containment vessel in the nuclear plant where the core melting accident has occurred. A method of opening the reactor pressure vessel,
By establishing an isolated area in the equipment temporary storage pool where radiation and radioactive materials do not leak to the driver's floor, the work of opening the reactor pressure vessel can be performed in parallel with the work of removing spent fuel from the fuel storage pool. A method of opening the reactor pressure vessel to secure space.
(2) The equipment temporary storage pool and the reactor well connected to the equipment temporary storage pool are formed on the operating floor of the reactor building, and the reactor well is covered with a shield plug to form the equipment temporary storage pool. The passage connecting the reactor wells is blocked by a throttle plug, and the reactor pressure vessel arranged in the reactor containment vessel in the nuclear plant in which the reactor containment vessel is arranged in the reactor building is opened. How to do
Secure a work space where the work of opening the reactor pressure vessel can be performed in parallel with the work of removing spent fuel from the fuel storage pool.
The work space is maintained in an isolated area where the upper surface of the equipment temporary storage pool is closed with a shield and an airtight lid so that radiation and radioactive substances do not leak to the operation floor, and the reactor well and the equipment temporary storage pool are provided. A reactor realized by forming a first through hole in the throttle plug that seals the reactor, disassembling the equipment in the reactor well through the first through hole, and carrying it out through the prepared equipment temporary storage pool. How to open the pressure vessel.
(3) As the maintenance of the isolated area in the equipment temporary storage pool, the equipment temporary storage pool has a function of having a shield that opens and closes on the upper surface and a function of making it airtight when closed, and a function of having a shield that opens and closes on the throttle plug side and airtightness. The method for opening the reactor pressure vessel according to (1) or (2).
(4) The inside of the reactor well sealed with the shield plug is decontaminated from the temporary storage pool of the equipment through the first through hole, and then the first radiation shield is transferred to the atom below the shield plug. The reactor pressure vessel according to (2), wherein the containment vessel head of the reactor containment vessel is covered with the first radiation shield to reduce contamination and radiation in the reactor well before disassembling the equipment in the reactor well. How to open.
(5) The first radiation shield is transferred from the temporary storage pool of the equipment into the reactor well sealed by the shield plug through the first through hole, and the reactor containment vessel is stored below the shield plug. A second radiation shield that also serves as a platform for disassembling the equipment in the reactor well instead of the shield plug in a state where the vessel head is covered with the first radiation shield and covered with the first radiation shield. The method of opening the reactor pressure vessel according to (2), wherein the equipment in the reactor well is replaced and disassembled.
(6) The platform that also serves as the second radiation shield is described in (5), wherein a dismantling work arm is attached to the lower surface so that the dismantling work arm can be moved in the circumferential direction, the radial direction, and the vertical direction in the reactor well. How to open the reactor pressure vessel.
(7) The equipment temporary storage pool and the reactor well connected to the equipment temporary storage pool are formed on the operating floor of the reactor building, and the reactor well is covered with a shield plug to form the equipment temporary storage pool. The passage connecting the reactor wells is blocked by a throttle plug, and the reactor pressure vessel arranged in the reactor containment vessel in the nuclear plant in which the reactor containment vessel is arranged in the reactor building is opened. How to do
The upper surface of the equipment temporary storage pool is closed with a shield and an airtight lid to maintain an isolated area where radiation and radioactive substances do not leak to the driver's floor.
A first through hole is formed in the throttle plug from the equipment temporary storage pool to form a first through hole.
After the first radiation shield is provided on the upper part of the equipment in the reactor well, the shield plug and the platform that also serves as the second radiation shield are replaced.
An airtight shredded area is formed in which the equipment temporary storage pool is shredded and a storage container for storing the shredded pieces is arranged.
A method in which the equipment in the reactor well is shredded and stored in a shredded area in the equipment temporary storage pool through the first through hole, and the reactor pressure vessel carried out of the equipment temporary storage pool is opened. ..
(8) The reactor pressure according to (7). How to open the container.
(9) As a method of carrying out the storage container in the shredded area arranged in the equipment temporary storage pool,
It has a container that can store water, a partition inside the container, and a passage through which the storage container can pass on the lower surface of the partition. The method for opening the reactor pressure vessel according to (7) or (8), which carries out through a water storage container having a carry-in inlet on one side and a carry-out port on the other side.
(10) After providing the first radiation shield on the upper part of the equipment in the reactor well, the shield plug and the throttle plug were removed.
An isolation house was set up on the operating floor of the equipment temporary storage pool and the reactor well.
Install a partition in the passage where the throttle plug that connects the temporary equipment pool and the reactor well was removed.
Partitions were installed in the equipment temporary storage pool and the isolation house on the operating floor of the reactor well.
Partitions will be installed on the operating floor of the equipment temporary storage pool and the reactor well.
The reactor according to (2) or (7), wherein the equipment temporary storage pool and the reactor well, the isolation house on the equipment temporary storage pool, and the isolation house on the reactor well are each independently divided into airtight chambers. How to open the pressure vessel.
(11) The partition that independently divides the equipment temporary storage pool and the reactor well, the isolation house on the equipment temporary storage pool, and the isolation house on the reactor well into airtight chambers has a function of shielding radiation. The method for opening the reactor pressure vessel according to (10).
(12) The method for opening the reactor pressure vessel according to (4), (5), (7) or (10), wherein a shield bag filled with water is used as the first radiation shield.
(13) After disassembling all the equipment in the reactor well covering the pressure vessel head attached to the reactor pressure vessel and carrying it out through the equipment temporary storage pool, the second device is attached to the pressure vessel head. A through hole is made, a camera is inserted through the second through hole, the inside of the pressure vessel head is inspected, and then the equipment inside the reactor pressure vessel is carried out to the outside of the reactor building (2) or (7). The method of opening the reactor pressure vessel described in.
(14) The method for opening the reactor pressure vessel according to (13), wherein the means for forming the second through hole and the camera are carried in through the equipment temporary storage pool.
(15) A means for forming a second through hole and a shielded container containing a camera are installed on the upper surface of the platform that also serves as a second radiation shield through an isolation house installed on the reactor well.
The means for forming the second through hole is provided by providing a removable stopper in advance in the passage hole for passing the means for forming the second through hole in the platform that also serves as the second radiation shield. A second through hole is made in the pressure vessel head attached to the reactor pressure vessel, the camera is inserted through the second through hole, and the inside of the pressure vessel head is investigated. After that, the method of opening the reactor pressure vessel according to (7), wherein the equipment in the reactor pressure vessel is carried out to the outside of the reactor building.
(16) The method for opening the reactor pressure vessel according to (13) or (15), which is reflected in the subsequent work of carrying out the equipment in the reactor pressure vessel based on the result of the investigation.
(17) The equipment temporary storage pool and the reactor well connected to the equipment temporary storage pool are formed on the operating floor of the reactor building, and the reactor well is covered with a shield plug to form the equipment temporary storage pool. The passage connecting the reactor wells is blocked by a throttle plug, and the reactor pressure vessel arranged in the reactor containment vessel in the nuclear plant in which the reactor containment vessel is arranged in the reactor building is opened. How to do
An isolation house was set up on the operating floor of the equipment temporary storage pool and the reactor well.
After removing the equipment in the reactor well,
An isolation vessel covering the pressure vessel head attached to the reactor pressure vessel was placed in the reactor well and the isolation house.
A method of opening a reactor pressure vessel in which the pressure vessel head removed from the reactor pressure vessel and the equipment in the reactor pressure vessel are removed in the isolation vessel.
(18) In the means for installing the isolation vessel covering the pressure vessel head attached to the reactor pressure vessel in the reactor well and the isolation house.
A removable closure plug is provided in advance in the passage hole through which the isolation container passes on the platform that also serves as the second radiation shield.
Described in (17), wherein when installing the isolation vessel, the isolation vessel is set by using the passage hole from which the closing plug has been removed, and the radiation shielding of the reactor well surface is carried out on the platform also used as the second radiation shielding body. How to open the reactor pressure vessel.
(19) The equipment temporary storage pool and the reactor well connected to the equipment temporary storage pool are formed on the operating floor of the reactor building, and the reactor well is covered with a shield plug to form the equipment temporary storage pool. The passage connecting the reactor wells is blocked by a throttle plug, and the reactor pressure vessel arranged in the reactor containment vessel in the nuclear plant in which the reactor containment vessel is arranged in the reactor building is opened. How to do
Secure a work space where the work of opening the reactor pressure vessel can be performed in parallel with the work of removing spent fuel from the fuel storage pool.
A whole cover device having a first sheet surrounding the side surface of the reactor building and a second sheet arranged above the operating floor of the reactor building and covering the upper surface having the first opening has been used from the fuel storage pool. It is configured to form the space required for the work performed in parallel with the fuel unloading work, and the gripper of the crane is moved below the overall cover device through the first opening to be placed on the operating floor of the reactor building. The falling object is grasped by the gripper and moved above the overall cover device through the first opening, the first opening is closed, and the reactor pressure vessel is opened after the removal work of the falling object. A method of opening the reactor pressure vessel in which the work is carried out.
(20) The method for opening a reactor pressure vessel according to (19), wherein the overall cover device can also be used for removing falling objects scattered on the operating floor inside the reactor building.
(21) The second sheet is a stretchable sheet, and a storage container in which the equipment in the reactor well or the equipment in the reactor pressure vessel is disassembled and stored is carried out from the first opening (21). 19) The method for opening the reactor pressure vessel according to the above.
(22) A device-encapsulating container having another crane provided with a gripping tool and an opening / closing sheet for opening / closing the collecting surface on the collecting surface of the fallen object is placed in the first opening or the space, and the opening / closing sheet is placed. While opening and closing the crane, the device in the reactor well or the device in the reactor pressure vessel is disassembled and stored in the carry-out container, and the disassembled piece is stored in the device inclusion container. The method for opening the reactor pressure vessel according to (19).
(23) The reactor according to any one of (2) to (22), wherein the equipment in the reactor well is a containment vessel head and a heat insulating material, or a containment vessel head and a heat insulating material, and a pressure vessel head. How to open the pressure vessel.
(24) The method for opening the reactor pressure vessel according to any one of (15) to (22), wherein the apparatus in the reactor pressure vessel is a steam separator or a steam dryer.
(25) After performing the work of opening the reactor pressure vessel by the method of opening the reactor pressure vessel according to any one of (1) 1 to (24), the fuel debris at the bottom of the reactor pressure vessel is removed. How to take out fuel debris to be disassembled and carried out to the outside of the reactor building.

2 ... Reactor, 3 ... Reactor pressure vessel, 4 ... Pressure vessel head, 5 ... Inferior mirror, 6 ... Core shroud, 7 ... Core, 9 ... Core support plate, 10 ... Upper lattice plate, 11 ... Air-water separation Vessel, 12 ... Steam dryer, 17 ... Reactor containment vessel, 18 ... Containment vessel head, 23 ... Reactor building, 24 ... Reactor floor, 25 ... Reactor well, 26 ... Dryer separator pool, 28 ... Shield plug, 29A , 29B ... Throttle plug, 30 ... Heat insulating material, 32 ... Radiation shielding container, 40 ... Isolation chamber, 41 ... Drilling device, 46 ... Decontamination device, 47 ... Shield body transport device, 48 ... Shielding bag, 49 ... Isolation house, 54 ... Isolation film, 70 ... Cutting and recovery device, 75 ... Carry-in / out chamber, 81 ... Isolation vessel, 81A ... Upper cylindrical member, 81B ... Intermediate cylindrical member, 81C ... Lower cylindrical member, 89, 90 ... Carry-in / out air lock, 94 ... Dismantling device, 95 ... Containment vessel transport device, 99 ... Cutting device, 100 ... Bio-shielding body, 210 ... Head investigation jig, 300 ... Overall cover device.

Claims (3)

It is a reactor building covering device that covers the entire reactor building of a nuclear power plant where a core meltdown accident occurred.
At least the columns installed at the four corners of the reactor building,
An isolation sheet for separating radioactive substances provided so as to cover the upper surface and the four side surfaces of the space surrounded by the columns provided at the four corners, and
Reactor building overall cover device An entire reactor building cover device equipped with an exhaust device that manages the inside of the reactor building to a negative pressure. In the reactor building entire cover device according to claim 1,
Frame members are provided on the upper parts of the columns provided at the four corners.
The frame member run line truck the reactor building operation floor top by two-dimensionally moved to the traveling member and the transverse member is being reactor building entire cover device mounted with an article entrance to. This is a reactor building preparation work method for opening the reactor pressure vessel and removing fuel debris from a nuclear power plant where a core meltdown accident occurred.
A method for preparing a reactor building for covering the entire reactor building by using the entire reactor building covering device according to claim 1 or 2.

Images