JP2016206154A - Method for opening reactor pressure vessel, and method for taking out fuel debris - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for taking out fuel debris, capable of reducing a risk of exposure to radiation.SOLUTION: The method comprises following steps: S1, setting a radiation shielding vessel in a dryer separator pool (DSP); S2, forming, from the radiation shielding vessel, a through hole in a throttle plug disposed at a passage connecting the DSP and a reactor well; S4, washing inside of the reactor well from the through hole, carrying-in a shielding bag through the through hole into the reactor well, and supplying water into the shielding bag; S5, covering the upper part of a storage vessel head with the shielding bag filled with the water in the reactor well shielded by a shield plug; S6, installing an isolation house for covering the reactor well on an operation floor to complete preparatory work and proceed to reactor opening work; S7, S8, removing the shield plug and the throttle plug; S9, disposing an isolation vessel in the reactor well and the insulation house; S12, covering a pressure vessel head with the isolation vessel; and S13, removing the pressure vessel head.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a method for opening a reactor pressure vessel and a method for taking out fuel debris, and more particularly, a method for opening a reactor pressure vessel suitable for application to a boiling water nuclear power plant and a method for taking out fuel debris. About.

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

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

  Japanese Patent Application Laid-Open No. 2013-19875 describes a method for extracting molten nuclear fuel material from a reactor pressure vessel in an atmospheric environment. In this molten nuclear fuel material removal method, two work houses, which are isolated houses that prevent the scattering of radionuclides to the external environment, are placed on the operation floor of the reactor building so as to cover the reactor well and are shielded. The plug is installed on the operation floor so as to cover the reactor well, and the reactor containment vessel head, the top cover of the reactor pressure vessel, and the steam drying in the reactor pressure vessel are performed using a boring device installed on the shield plug. A hole is made in the vessel and the steam separator. The state of the core is observed by a camera inserted into the core through this hole, and when the fuel assembly in the core is melted, a granular radiation shield is filled into the core through the hole.

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

  In the method for taking out molten nuclear fuel material described in Japanese Patent Application Laid-Open No. 2013-19875, four additional floors each having a guide rail that is an arc of a quarter of a circle are attached to the upper surface of each of them are installed on the operation floor. The By installing additional floors on the operation floor, the guide rails on each additional floor are connected to form a guide rail that becomes one circle. The electromagnet suspended from the overhead crane in the isolation house is attached to the outer surface of the reactor containment head, and the cutting device is moved along the guide rail while being provided at the lower end of the expansion tube of the cutting device. The head of the containment vessel is cut with a cutting device attached to the tip of the arm. The cut head is lifted into the isolation house by pulling up the electromagnet suspended from the overhead crane, and is carried outside. For the upper lid of the reactor pressure vessel, the bolt that fixes 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 by the overhead crane in the isolation house is attached to the reactor pressure vessel as with the reactor containment head. The upper lid is cut into a circular shape by the cutting device attached to the outer surface of the upper lid and moved along the guide rail, and the cut upper lid is pulled up into the isolation house.

  Each of the steam dryer and the steam separator installed in the reactor pressure vessel is cut, and the cut pieces are taken out into the isolation house. In Japanese Unexamined Patent Publication No. 2013-19875, fuel debris present at the bottom of the reactor pressure vessel is subsequently taken out using a boring device.

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

  Japanese Patent Application Laid-Open No. 2011-106529 describes a robot arm type robot. The robot arm type robot described in paragraphs 0189 to 0200 of JP 2011-106529 A connects a plurality of actuators 200 ′ that can bend freely in the vertical and horizontal directions, and bends in only one direction by hydraulic pressure and a wire mechanism. A plurality of actuators 100 ′ that cannot be mounted are attached to the actuator 200 ′ at the tip.

  JP 2013-217705 describes a method for removing damaged fuel. In this damaged fuel removal method, nitric acid is supplied into the reactor pressure vessel in which the fuel debris has fallen to the bottom, the fuel debris is dissolved and liquefied with nitric acid, and the liquid in which the fuel debris is dissolved is removed from the reactor pressure vessel. It is taken out from.

JP 2013-19875 A JP 2014-70946 A JP 2011-106529 A JP 2013-217705 A

  In the method of taking out molten nuclear fuel material described in JP2013-198575A, an isolated house is installed on the operation floor of the reactor building so as to cover the reactor well, and installed at the upper end of the reactor well. The shield plug that seals the well is removed.

  When the shield plug is removed, the containment head in a healthy state is attached to the upper end of the containment vessel, so that the containment of the containment vessel is maintained and even if a core melting accident occurs, the containment vessel The radioactive material within is not released into the reactor well formed above the containment head. However, when the airtightness by the containment vessel head is impaired, the radioactive substance in the reactor containment vessel may be released to the reactor well sealed with the shield plug. In such a case, by removing the shield plug that seals the reactor well, the radioactive material released into the reactor well enters the isolation house, and the isolation house is contaminated with the radioactive material. For this reason, radioactive material accumulates in the isolation house itself and becomes a pollution source, and the surrounding dose equivalent rate rises, preventing the worker from approaching the isolation house. In addition, since various equipment installed in the isolation house is contaminated, it is necessary to decontaminate all equipment in and out of the isolation house, which causes a reduction in workability.

  Further, it is desired to further reduce the time required for taking out fuel debris.

  It is a first object of the present invention to provide a method for opening a reactor pressure vessel that can reduce the risk of exposure.

  Another object of the present invention is to provide a fuel debris retrieval method that can further reduce the time required for fuel debris retrieval.

A feature of the present invention that achieves the first object described above is that the equipment temporary storage pool and the reactor well communicated with the equipment temporary storage pool are formed on the operation floor of the reactor building, and the reactor well is covered with a shield plug. The passage connecting the equipment temporary storage pool and the reactor well is sealed with a throttle plug, and is placed in the reactor containment vessel in the nuclear power plant where the reactor containment vessel is placed in the reactor building. A method of opening a reactor pressure vessel,
Install a radiation shielding container in the equipment temporary pool,
A first through hole is formed in the throttle plug from inside the radiation shielding container,
The first radiation shielding body is transferred from the radiation shielding container into the reactor well sealed by the shield plug through the first through hole, and the containment head of the containment vessel is moved by the first radiation shielding body below the shield plug. There is to cover.

  With the reactor well sealed with a shield plug, the first radiation shield is transferred from the radiation shielding container installed in the equipment temporary storage pool into the reactor well through the first through hole formed in the throttle plug. Since the containment vessel head can be covered with the first radiation shielding body and the shield plug can be removed, and radiation from below the containment vessel head can be shielded by the first radiation shielding body, so Prevention of radioactive dust diffusion and dose reduction will be handled by a radiation shielding container installed in the equipment temporary storage pool, and diffusion of radioactive dust and leakage of dose can be prevented on the operation floor of the reactor building.

Another feature of the present invention that achieves the first object described above is that the equipment temporary storage pool and the reactor well communicated with the equipment temporary storage pool are formed on the operation floor of the reactor building, and the reactor well is a shield plug. The passage connecting the equipment temporary storage pool and the reactor well is sealed with a throttle plug, and placed in the reactor containment vessel in a nuclear power plant where the reactor containment vessel is placed in the reactor building. A method of opening a reactor pressure vessel, comprising:
An isolation house covering the reactor well is installed on the operation floor,
Remove the shield plug with the containment head covered with the first radiation shield,
An isolation vessel covering the pressure vessel head attached to the reactor pressure vessel is placed in the reactor well and the isolation house,
In the isolation vessel, the pressure vessel head removed from the reactor pressure vessel is transferred upward.

  The isolation vessel covering the pressure vessel head attached to the reactor pressure vessel with the shield plug removed is placed in the reactor well and the isolation house, and the pressure vessel head removed from the reactor pressure vessel in the isolation vessel Since the radioactive material from the reactor pressure vessel is diffused into the small-capacity isolation vessel by removing the pressure vessel head, the area contaminated by the radioactive material is limited in the isolation vessel. can do. For this reason, radionuclides from the reactor pressure vessel are not diffused into the isolated house on the operating floor, so that it is possible to prevent an increase in dose on the operating floor due to contamination of the isolated house, and also prevent contamination of equipment used in the isolated house. it can.

Another feature of the present invention that achieves the second object described above is to open the reactor pressure vessel by removing the pressure vessel head attached to the reactor pressure vessel,
Forming a second through hole in the bottom of the reactor pressure vessel;
In the reactor pressure vessel, the reactor internal structure and fuel debris in the reactor pressure vessel are cut,
Each of the pieces of the reactor internal structure and the fuel debris is discharged through the second through hole to a region surrounded by the reactor pressure vessel support member below the reactor pressure vessel.

  A second through-hole is formed in the bottom of the reactor pressure vessel, and the internal structure and fuel debris cut in the reactor pressure vessel are cut below the reactor pressure vessel through the second through-hole. Since it is discharged to the area surrounded by the reactor pressure vessel support member, it is possible to carry out the cutting operation in the reactor and the operation of storing the generated cut pieces in the storage container and carrying out the storage container in parallel, It is possible to shorten the time required for taking out the reactor internal structure and fuel debris in the reactor pressure vessel out of the reactor pressure vessel.

  According to the present invention, the risk of exposure to workers can be reduced.

It is a longitudinal cross-sectional view of the reactor building of a boiling water nuclear power plant. It is a top view of the operation floor of a nuclear reactor building. It is a flowchart which shows a part of procedure of the removal method of the fuel debris of Example 1 applied to the boiling water nuclear power plant which is one suitable Example of this invention. It is a flowchart which shows the remainder of the procedure of the removal method of the fuel debris of Example 1. It is explanatory drawing which shows each state of the dryer separator pool and reactor well formed in the reactor building before starting the opening of the reactor pressure vessel included in the procedure of the fuel debris retrieval method. 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 carrying-in state of the punching apparatus in the radiation shielding container installed in the dryer separator pool. It is explanatory drawing which shows the state of the drilling apparatus installed in the front surface of the throttle plug of a drilling object in a radiation shielding container. It is explanatory drawing which shows the state which punches a throttle plug using a punching apparatus. It is explanatory drawing which shows the state which took out the block which the throttle plug cut | disconnected. It is explanatory drawing which shows the installation state of the handrail removal apparatus in a radiation shielding container. It is explanatory drawing which shows the removal operation | work of the handrail of the containment vessel head arrange | positioned in the nuclear reactor well using the handrail removal apparatus. 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 operation | work in a reactor well using a decontamination apparatus. It is explanatory drawing which shows the installation state of the radiation shielding body installation apparatus in a radiation shielding container. It is explanatory drawing which shows the carrying-in operation | work of the radiation shielding bag in a reactor well using a radiation shielding body installation apparatus. It is explanatory drawing which shows the state of the radiation shielding bag carried in in 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 with the some radiation shielding bag arrange | positioned in the nuclear reactor well, and was expanded by water supply. It is explanatory drawing which shows the state which installed the isolation house which covers a dryer separator pool and a reactor well on the operation floor of a reactor building. It is explanatory drawing which shows the removal operation | work of a shield plug. It is explanatory drawing which shows the state which accommodates the removed shield plug in the carrying-out container arrange | positioned in the isolation house on the upper surface of a radiation shielding container. It is explanatory drawing which shows the removal operation | work of a slot plug. It is explanatory drawing which shows the state in the middle of conveyance of the removed slot plug. It is explanatory drawing which shows the state which accommodates the removed slot plug in the carrying-out container arrange | positioned on the upper surface of the radiation shielding container in an isolation house. It is explanatory drawing which shows the state which removed the side wall by the side of the reactor well of the radiation shielding container installed in the dryer separator pool. The isolation wall which divides the inside of the isolation house into the first area just above the dryer separator pool and the second area just above the reactor well, and the attachment state of the new side wall to the reactor well side of the radiation shielding container are shown. It is explanatory drawing. It is explanatory drawing which shows the state which carried in the 2nd area directly above the reactor well in an isolation house of the containment vessel head suspension device provided with the containment vessel head cutting device. It is explanatory drawing which shows attachment of the storage container head suspension apparatus to a storage container head, and cutting | disconnection of the storage container head by a storage container head cutting device. It is explanatory drawing which shows the decontamination operation | work of the inner surface of the storage container head cut | disconnected and hung up. It is explanatory drawing which shows the carrying-out operation | work of the container container head decontaminated. It is explanatory drawing which shows the removal operation | work of a baffle plate. It is explanatory drawing which shows each operation | work of the removal of another baffle plate, and the radiation shielding plate installation between a reactor pressure vessel and a reactor containment vessel. It is explanatory drawing which shows each operation | work of installation of the other radiation shielding plate and support beam member installation between a reactor pressure vessel and a reactor containment vessel. It is explanatory drawing which shows the installation operation | work of another support beam member. It is explanatory drawing which shows the state which has arrange | positioned the isolation container which covers a pressure vessel head inside each of a reactor well and the 2nd area in an isolation house. It is explanatory drawing which shows the state which lifts a pressure vessel head within an isolation container. It is explanatory drawing which shows the decontamination operation | work of the inner surface of the pressure vessel head hung up in the isolation container. It is explanatory drawing which shows carrying out the decontaminated pressure vessel head out of the isolation container. It is explanatory drawing which shows the removal operation | work of the steam dryer in an isolation container. It is explanatory drawing which shows carrying out to the isolation container of the removed steam dryer. It is explanatory drawing which shows carrying in in the radiation shielding container installed in the dryer separator pool of the removed steam dryer. It is explanatory drawing which shows the other example of the removal operation | work of the steam dryer in an isolation container. It is explanatory drawing which shows the through-hole formation work to the lower mirror part of a reactor pressure vessel. It is explanatory drawing which shows the cutting operation | work of the reactor internal structure in the reactor pressure vessel by a rotary cutting device. It is a side view of the rotary cutting device shown in FIG. It is a YY arrow line view of FIG. It is explanatory drawing which shows the collection | recovery operation | work of the cutting piece of the fuel debris dropped from the reactor pressure vessel to the area | region inside a pedestal. It is explanatory drawing which shows the state which has arrange | positioned the carrying-out apparatus which carries out the cutting piece of the fuel debris which fell to the area | region inside the pedestal outside the pedestal in the opening part of a pedestal. It is a top view of the carrying-out apparatus shown in FIG. It is explanatory drawing which shows operation | movement of supply of the cutting piece of a fuel debris into the storage container by the carrying-out apparatus shown in FIG. 48, and supply stop. It is explanatory drawing which shows the other example of the collection | recovery operation | work of the cutting piece of the fuel debris dropped from the nuclear reactor pressure vessel to the area | region inside a pedestal. It is a flowchart which shows a part of procedure of the extraction method of the fuel debris of Example 2 applied to the boiling water nuclear power plant which is another suitable Example of this invention. It is explanatory drawing which shows the state which removed the some radiation shielding bag which was arrange | positioned in the reactor well and covered the containment vessel head, and was expanded by the water supply. It is explanatory drawing which shows the state which carried in the 2nd area directly above the reactor well in an isolation house of the containment vessel head suspension device provided with the containment vessel head cutting device. It is explanatory drawing which shows the cutting operation of the storage container head by the storage container head cutting device attached to the storage container head suspension apparatus. It is explanatory drawing which shows the decontamination operation | work of the inner surface of the storage container head cut | disconnected and hung up. It is explanatory drawing which shows the carrying-out operation | work of the container container head decontaminated. It is explanatory drawing which shows the example which operates remotely the operation | work in a furnace and the carrying out operation | work of the debris which fell to the area | region inside the pedestal by the operation operation room.

  Examples of the present invention will be described below.

  A method of taking out fuel debris of Example 1, which is a preferred embodiment of the present invention, will be described below with reference to FIGS. The fuel debris retrieval method of this embodiment is applied to a boiling water nuclear power plant. The fuel debris retrieval method of this embodiment includes opening of the reactor pressure vessel and fuel debris retrieval.

  The method for opening the reactor pressure vessel, which is a part of the fuel debris retrieval method of the present embodiment, includes the preparatory work (including steps S1 to S6) and the reactor open work (step S7) shown in FIG. -Each process of S13 is included. Further, this fuel debris retrieval method includes the operation of removing fuel debris that has fallen to the bottom of the reactor containment vessel shown in FIG. 4 (including steps S17 to S20) and the fuel debris that has fallen to the bottom of the reactor containment vessel. Extraction work (including steps S14 to S16 and S21 to S24).

  Before describing the fuel debris retrieval method of this embodiment, the schematic configuration of a boiling water nuclear power plant to which this fuel debris retrieval method is applied will be described with reference to FIGS. 1 and 2.

  The boiling water nuclear power plant 1 includes a nuclear reactor 2 and a reactor containment vessel 17. The reactor containment vessel 17 is installed in the reactor building 23, and a containment vessel head 18 that is a lid is attached to the upper end portion of the reactor containment vessel 17 and 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 shielding body 100 that becomes a part of the reactor building 23.

  A shield plug 28, which is a radiation shielding body divided into a plurality of parts, is disposed directly above the containment vessel head 18, and these shield plugs 28 are disposed in the reactor well 25 and are placed on the operation floor 24 of the reactor building 23. is set up. The shield plug 28 seals the reactor well 25. A dryer separator pool (equipment temporary storage pool) 26 and a fuel storage pool 27 are disposed adjacent to the reactor well 25 and surrounded by the operation 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, and the water channel is sealed by a plurality of throttle plugs (gate members) 29A at least during the operation of the boiling water nuclear power plant 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, and the water channel is sealed by a plurality of stacked throttle plugs (gate members) 29B at least during the operation of the boiling water nuclear power plant 1.

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

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

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

  The reactor pressure vessel 3 is installed on a cylindrical pedestal 15 provided on a concrete mat 16 provided at the bottom in the reactor containment vessel 7. A cylindrical gamma 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 nuclear power plant 1, in a state where the reactor is scrammed and the reactor power is reduced, all the power sources for supplying the current of the boiling water nuclear power plant 1 are temporarily lost and used in an emergency. Assume that a situation has occurred in which the core cooling system has not been activated. When all the power supplies are lost and the pumps of the emergency core cooling system do not operate and the cooling of the fuel rods included in the fuel assemblies 8 in the core 7 is impaired, the fuel rods The contained nuclear fuel material is melted, and the structural members of the fuel assembly 8, such as the fuel rod cladding, the channel box of the fuel assembly 8, the upper tie plate, and the lower tie plate are melted by the melting of the nuclear fuel material. There is a possibility that the fuel debris 39 </ b> A, which is a melt of nuclear fuel material and structural members of the fuel assembly 8, will fall on the inner surface of the lower mirror portion 5 that is the bottom of the reactor pressure vessel 3. In some cases, the fuel debris 39A includes a melt of a reactor internal structure such as the core support plate 9 or the like. The fuel debris 39A that has melted and dropped onto the inner surface of the lower mirror portion 5 is cooled and hardened.

  In the event that such 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 removed. Decommissioning treatment is carried out for the boiling water nuclear power plant 1 that has fallen. Further, a part of the fuel debris 39A that has fallen to the bottom of the reactor pressure vessel 3 is the bottom of the reactor containment vessel 17 in the pedestal 15, further below the lower mirror portion 5 of the reactor pressure vessel 3, that is, concrete. There is also a possibility of dropping onto the mat 16. The fuel debris that has dropped to the bottom of the reactor containment vessel 17 in the pedestal 15 is referred to as fuel debris 39B.

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

  The fuel debris retrieval method of this embodiment will be described below. First, preparation work in a method of opening a reactor pressure vessel, which is a part of the fuel debris retrieval method of the present embodiment, will be described. This preparatory work is a work prior to the reactor opening work.

  A radiation shielding container is installed in the DSP (step S1). Using a mobile crawler crane (not shown) installed outside the reactor building 23, the radiation shielding container 32 is lifted and installed in the DSP 26 (see FIG. 6). In addition, this crane should just be what can carry in and out heavy goods, such as a portal crane and a tower crane. The radiation shielding container 32 is attached to the radiation shielding container 32 with the radiation shielding plate 33 having the opening 36A formed as a ceiling member, and the opening 36B is formed on the side wall on the reactor well 25 side. A movable door 34 that opens and closes the opening 36 </ b> A is attached to the radiation shielding container 32. A movable door 35 that opens and closes the opening 36B is attached to the inner surface of the side wall on the reactor well 25 side. The opening 36B is sealed by the door 34, and the opening 36B is sealed by the door 35, respectively.

  A through hole is formed in the slot plug (step S2). The isolation chamber 40 in which the punching 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 40 </ b> A is attached to the lower surface of the isolation chamber 40, and an opening 40 </ b> E is formed on one side wall of the isolation chamber 40. The opening 40E is opened and closed by a door 40B that is movably attached to the inner surface of the side wall. An annular sealing device 40C surrounding the opening 40E is attached to the outer surface of the side wall of the isolation chamber 40.

  The punching device 41 is disposed in the space 40D in the isolation chamber 40 and is attached to the upper end portion of the support member 42 that is movably 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 to the side wall of the radiation shielding container 32 on the reactor well 25 side by the carriage 40A. 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 immediately before 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 piercing device (for example, a wire saw) 41 is driven, and the piercing device 41 is moved toward one slot plug 29A made of concrete, thereby cutting the slot plug 29A into blocks. The cutting position of the slot plug 29A using the drilling device 41 is a position below the lower surface of the shield plug 28 positioned at the lowest position among the shield plugs 28 sealing the reactor well 25 (see FIG. 9). . The block 44 of the shield plug 28 cut out by the punching 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 communicates, and the gas containing the radionuclide 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. Thereafter, the door 40B is 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 in which a gas containing a radioactive substance exists, is carried out from the DSP 32 to the ground by the crawler crane through the opening 36A. Thereafter, the isolation chamber 40 containing the perforation device 41 is disposed. At the time of this disposal, the gas containing the radioactive substance in the isolation chamber 40 is supplied to the purification device and removed by the purification device.

  The handrail provided on the storage container 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, similarly to the step S2. After the isolation chamber 40 is carried in, the door 34 is closed. The isolation chamber 40 is moved in the radiation shielding container 32 until the sealing device 40C comes into contact with the inner surface of the side wall on the reactor well 25 side of the radiation shielding container 32 (see FIG. 11). The door 35 is opened immediately before the sealing device 40C is pressed against the side wall.

  The handrail removing device 45 includes a slide mechanism 45B attached to the upper end of the support member 42, an extendable tube 45A installed on the slide mechanism 45B, and two work arms 45C attached to the distal end of the extendable tube 45A. A gripping tool (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 a multi-joint and can be freely bent vertically and horizontally. The work arm 45 </ b> C includes, for example, a plurality of actuators 200 ′ described in JP 2011-106529 A and connected to each other.

  The door 40B is opened and the space 40D in the isolation chamber 40 is communicated with the reactor well 25. The extension tube 45A is inserted into the through hole 43 by the movement of the slide mechanism 45B, and the extension tube 45A is further extended toward the reactor well 25. The handrail 31 attached to the storage container head 18 is gripped by a gripping tool of one work arm 45C and cut by a cutter of another work arm 45C (see FIG. 12). The cut piece of the handrail 31 gripped by the gripping tool is moved into the isolation chamber 40 by the movement of the slide mechanism 45B and the telescopic tube 45A, and stored in the isolation chamber 40. In this way, the handrail 31 is sequentially cut. After all the handrails 31 are removed, the work arm 45C of the handrail removing device 45 is housed in the isolation chamber 40, and the doors 40B and 35 are closed. The isolation chamber 40 storing the handrail removing device 45 and the cut pieces of the handrail 31 is suspended from the crawler crane and conveyed from the radiation shielding container 32 to the ground through the opening 36A.

  A camera (not shown) is attached to the distal end portion of the telescopic tube 45A to which the work arm 45C is attached, and work (for example, cutting of the handrail 31) in the reactor well 25 is photographed by this camera. The video imaged by the camera is transmitted to the operation floor of the reactor building 23 or the monitor of the operation operation room 140 (see FIG. 58) installed in a separate building, and is monitored by a worker. This camera is also attached to the distal end portion of each telescopic tube 45A of the decontamination device 46 and the shield transport 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, and the door 34 is closed thereafter, as in the step S2. The sealing device 40C of the isolation chamber 40 is brought into contact with the inner surface of the side wall on the reactor well 25 side of the radiation shielding container 32 (see FIG. 13). The door 35 is opened immediately before the sealing device 40C is pressed against the side wall.

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

  The door 40B is opened and the space 40D in the isolation chamber 40 is communicated with the reactor well 25. As the slide mechanism 45B and the telescopic tube 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 sprayed from the spray nozzle 46A, and, for example, decontamination of the lower surface of the shield plug 28 is performed (see FIG. 14). The cleaning water is supplied by a water supply hose (not shown) installed along the telescopic tube 45A and the work arm 45C. The water supply hose extends from the isolation chamber 40 to the outside of the radiation shielding container 32 and is connected to the makeup water system. The telescopic tube 45A is expanded and contracted to bend the working arm 45C vertically and horizontally to decontaminate the outer surface of the storage container 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 apparatus 46 are accommodated in the isolation chamber 40, and the doors 40B and 35 are closed. The isolation chamber 40 that houses the decontamination device 46 is suspended from the crawler crane and conveyed from the radiation shielding container 32 to the ground through the opening 36A.

  The cleaning water sprayed and dropped from the spray nozzle 46A toward the lower surface of the shield plug 28 at the time of decontamination is received by a cleaning water tray (not shown) attached to the work arm 45C and connected to the cleaning water tray. The water is stored in a drain tank (not shown) provided in the isolation chamber 40 through the drain hose. The cleaning water used for decontamination of the outer surface of the containment head 18 and the inner surfaces of the throttle plugs 29 </ b> A and 29 </ b> B cannot be received by the cleaning water tray and falls to the upper surface of the baffle plate 76 in the reactor well 25. . The washing water dropped on the upper surface of the baffle plate 76 is driven by a pump (not shown) connected to the drain tank of the isolation chamber 40 and sucked by a drain hose (not shown) connected to this pump. Stored in the tank. The water stored in the drain 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 in which the shielding body transfer device 47 and the folded shielding bag 48 are accommodated is carried into the radiation shielding container 32 through the opening 36A, and then the door is opened. 34 is closed. The shielding bag 48 is a bag made of a composite sheet composed of a sheet having stretch properties and fibers that maintain strength, and is folded. This sheet may incorporate fibers having high strength, high elasticity, and high ductility as required. The shielding bag 48 may be made of elastic elastic rubber. The sealing device 40C of the isolation chamber 40 is brought into contact with the inner surface of the side wall on the reactor well 25 side of the radiation shielding container 32 (see FIG. 15). The door 35 is opened immediately before the sealing device 40C is pressed against the side wall.

  Similarly to the handrail removing device 45, the shielding body transport device 47 includes a slide mechanism 45B, an extendable tube 45A, and a work arm 45C attached to the upper end portion of the support member 42. A gripping tool 47A is attached to the tip of the work arm 45C.

  The door 40B is opened and the space 40D in the isolation chamber 40 is communicated with the reactor well 25. In the space 40D, the gripping tool 47A grips one shielding bag 48 existing in the space 40D. The slide mechanism 45B and the telescopic tube 45A move toward the reactor well 25, so that the work arm 45C and the gripping tool 47A that holds the shielding bag 48 are contained in the reactor well 25 and the containment vessel head 18 and the shield plug 28. Inserted between. The shielding bag 48 grasped by the grasping tool 47A is moved to a predetermined position in the reactor well 25 above the containment head 18 (see FIG. 16). Thereafter, a water supply hose (not shown) installed along the telescopic tube 45A and the work arm 45C is connected to a check valve provided in the shielding bag 48, and the water supplied by the water supply hose has a check valve. It is supplied into the shielding bag 48 through the one-touch coupler. The shielding bag 48 is inflated by supplying water, covers a part of the storage container head 18, and is disposed between the storage container head 18 and the shield plug 28 (see FIG. 17).

  The water supply hose installed along the work arm 45C is removed from the one-touch coupler with a 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 tube 45A. Here, the gripping tool 47A grips 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 necessary number of shielding bags 48 are transferred into the reactor well 25 and expanded by water, so that the containment vessel head 18 is disposed between the containment vessel head 18 and the shield plug 28. It is covered with a plurality of shielding bags 48 inflated with water (see FIG. 18). These shielding bags 48 filled with water serve as radiation shielding bodies (first radiation shielding bodies).

  Since the through hole 43 is formed in the throttle plug 29A, the storage container 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 shielding body transport device 47 in the isolation chamber 40. It can be easily transferred between. For this reason, it is possible to easily install the shielding bag 48 filled with water, that is, the first radiation shielding body covering the storage container head 18.

  By arranging these shielding bags 48 filled with water between the storage container head 18 and the shield plug 28, radiation from the lower side of the storage container head 18 is absorbed by these shielding bags 48 filled with water. Can be shielded. As a result, decontamination in the contaminated reactor well and installation of shields are accessed from the equipment temporary pool side, so that the diffusion of radioactive dust from the reactor well and leakage of dose are installed in the equipment temporary storage pool. Therefore, it is possible to prevent leakage of radioactive dust and dose directly on the operation floor. Further, as will be described later, even when the shield plug 28 is removed, the dose on the operation floor 24 can be reduced. In addition, since the shielding bags 48 filled with water are disposed in the reactor well 25, the flow of air in the reactor well 25 is inhibited, and the diffusion of radioactive dust can be prevented.

  After the installation of a predetermined number of shielding bags filled with water into the reactor well 25 is completed, the work arm 45C and the gripping tool 47A of the shielding body transport device 47 are accommodated in the isolation chamber 40, and the doors 40B and 35 are provided. Is closed. The isolation chamber 40 that houses the shielding body transport device 47 is suspended from the crawler crane and transported from the radiation shielding container 32 to the ground through the opening 36A.

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

  An isolation house is installed on the operation floor of the reactor building (step S6). The isolation house 49 is transported to the operation floor 24 of the reactor building 23 using a crawler crane, and the isolation house 49 is installed on the operation floor 24 (see FIG. 19). The isolation house 49 covers the DSP 26, that is, the radiation shielding container 32 and the reactor well 25. On the side wall of the isolation house 49, an opening (not shown) serving as an entrance into and out of the isolation house 49 is formed, and a door (not shown) for opening and closing the opening is attached to be movable. An operator can enter the space 53 in the isolation house 49 from the operation floor 24 through the opening formed in the side wall of the isolation house 49 and having the door opened. 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 a space 53 in the isolation house 49. A rotating drum (not shown) that winds and unwinds the wire 56 attached to the gripper 52 is attached to the traversing carriage of the overhead crane 50.

  Thus, each step of the preparation work in the method for opening the reactor pressure vessel is completed. Next, the reactor opening operation in the method of opening the reactor pressure vessel will be described.

  The shield plug is removed (step S7). An annular isolation film storage container 73 is disposed on the radiation shielding container 32, the operation floor 24 and the throttle plug 29B so as to surround the throttle plug 29A and the shield plug 28 in the isolation house 49. The isolation film 54 taken out from the isolation film storage container 73 is disposed so as to cover the throttle plug 29A and the shield plug 28. The gripping tool 52 of the overhead crane 50 grips a lifting 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 shield plug 28 that has been lifted is wrapped with the isolation film 54, and the isolation film 54 is welded at the position X shown in FIG. 20 that is wrapped and squeezed, and the isolation film 54 is cut at the welded portion.

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

  The throttle plug is removed (step S8). Although all the shield plugs 28 have been removed, the containment head 18 is covered with a shielding bag 48 filled with water, so that radiation from below the containment head 18 is shielded with water. 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 shielding bag 48 filled with water in the reactor well 25. The gripping tool 52 of the overhead crane 50 grips a lifting tool (not shown) attached to one throttle plug 29A from above the isolation film 54 (see FIG. 22). The wire 56 is wound up, the throttle plug 29A is lifted up to a predetermined position, the lifted throttle plug 29A is wrapped in the isolation film 54, and the isolation film 54 is welded and welded at the position where it is wrapped and squeezed in the same manner as the shield plug 28. The isolation film 54 is cut at a portion (see FIG. 23).

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

  Thereafter, steps S8A to S8D that are not shown in FIG. 3 and are part of the nuclear reactor opening operation are performed. Each process of step S8A-S8E is demonstrated below.

  The side wall on the reactor well 25 side of the radiation shielding container 32 is removed (step S8A). The side wall on the reactor well 25 side of the radiation shielding container 32 is detached from the radiation shielding container 32 with the door 35 attached, lifted by the overhead crane 50, and transferred to the space 53 in the isolation house 49. Further, the side wall is transferred from the inside of the isolation house 49 onto the operation 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 is 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 water channel connecting the DSP and the reactor well is removed (step S8B). The isolation chamber 40 in which the punching device 41 used in step S2 is accommodated is conveyed from the ground onto the operation floor 24 by the crawler crane, and is moved into the isolation house 49 from the opening formed in the isolation house 49. The Although not shown in FIG. 25, the isolation chamber 40 is carried into the radiation shielding container 32 through the opening 36 </ b> A that is 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 container 32 and is stopped near the protrusion 57 formed at the bottom of the water channel connecting the DSP 26 and the reactor well 25. . Using a piercing device (eg, a wire saw) 41, the protrusion 57 is cut so as not to damage the water-filled shielding bag 48 covering the containment head 18. The plurality of blocks (not shown) of the cut protrusions 57 are accommodated in the space 40D in the isolation chamber 40. The isolation chamber 40 storing these blocks is transferred into the isolation house 49 through the opening 36 </ b> A contrary to the time of loading, and further transferred onto the operation floor 24 outside the isolation house 49 and to the ground. . As shown in FIG. 26, a flat bottom surface 57A is formed in the portion of the water channel from which the protruding portion 57 is removed.

  The removal of the protrusion 57 facilitates installation of a carry-in / out air lock 89 described later (see FIG. 35) without being obstructed by the protrusion 57. For this reason, using the carry-in / out air lock 89, a carry-out route into the radiation shielding container 32 of the reactor internal structure removed in the reactor pressure vessel 3 can be easily secured.

  A new side wall of the radiation shielding container is installed (step S8C). A side wall 63 having an opening 63A formed on the lower side and doors 64A and 64B for opening and closing the opening 63A is movably attached to the ceiling crane 50 and is suspended from the space 53 in the isolation house 49. Lowered into the furnace well 25. The side wall 63 is attached to the end of the radiation shielding vessel 32 on the reactor well 25 side by welding. An open / close type isolation sheet 65 attached to the inner surface of the radiation shielding container 32 is disposed closer to the radiation shielding container 32 than the side wall 63. The side wall 63 may be manufactured by welding a plurality of steel plates in the isolation house 49.

  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 51A and 51B are installed on the guide rails 51A and 51B (see FIG. 26). A traveling crane carried into the isolation house 49 is used to remove the overhead crane 50 and install the overhead cranes 51A and 51B. After the overhead cranes 51A and 51B 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. Is attached to the inner surface of the isolation house 49 by welding (see FIG. 26).

  By attaching the isolation wall 60, two spaces 53 </ b> A and 53 </ b> B are formed in the isolation house 49. An overhead crane 50A and a guide rail 51A are disposed in a space 53A formed immediately above the reactor well 25, and an overhead crane 50B and a guide rail 51B are disposed in a space 53B formed immediately above the radiation shielding container 32. Is placed. A gripping tool 52A is attached to the wire 56A attached to the overhead crane 50A, and a gripping tool 52B is attached to the wire 56B attached to the overhead crane 50B. An openable / closable isolation sheet 62 attached to the inner surface of the isolation house 49 is disposed closer to the space 53 </ b> B than the door 61. A plate-like floor member 58 that forms the bottom surface of the space 53 </ b> A is attached to the lower end portion of the isolation house 49. In the floor member 58, an opening 58A having the same size as the inner diameter of the reactor well 25 is formed.

  A second radiation shield is installed (step S9). In the isolation house 49, a radiation shielding body (second radiation shielding body) 59 constructed by connecting a plurality of radiation shielding plates so as to be folded together covers the reactor well 25 using the overhead crane 50A. It is removably installed on the floor member 58 that forms the bottom surface of the space 53A (see FIG. 26). The radiation shielding body 59 includes a driving device that folds and extends a plurality of radiation shielding plates. In addition, this radiation shielding board is good also as a structure which can arrange | position several water shielding bags, can be folded by water injection or drainage, and can also be opened and closed. An openable isolation sheet 54 stored in the isolation film storage container 73 is disposed so as to cover the radiation shielding body 59 installed so as to cover the reactor well 25. The radiation shield 59 is conveyed on the operation floor 24 outside the isolation house 49 by the crawler crane in a folded state, and further transferred into the space 53A via the space 53B. The folded radiation shielding body 59 is suspended from the overhead crane 50A and placed on the floor member 58 through the opening of the openable / closable isolation sheet 54, and the opening 58A of the floor member 58 is driven by the driving device described above. It is stretched to cover.

  The equipment in the reactor well is removed and carried out (step S10). 27. FIG. This will be described with reference to FIGS. 29 and 30. FIG.

  Similar to the radiation shielding body 59, the suspension balance 66 is carried into the space 53 </ b> A in the isolation house 49. To the suspension balance 66, a suspension bar 68A having a gripping tool 67A attached to the lower end portion and a suspension rod 68B having a gripping tool 67B attached to the lower end portion are respectively attached downward, and a cutting device 70 is further attached. The cutting device 70 includes a moving device 78, a telescopic tube 77 that extends downward and is attached to the transfer device 78, and a cutting machine 69 that is attached to the lower end of the telescopic tube (see FIG. 27). A ring-shaped guide rail (not shown) for turning the cutting device 70 around the storage container head 18 is attached to the lower surface of the suspension balance 66 which is a disc, and the moving device 78 is below the guide rail. It is movably attached to the side. The outer diameter of the suspension balance 66 is slightly smaller than the inner diameter of the opening 58A so that the fishing balance 66 passes through the opening 58A.

  Each shielding bag 48 filled with water and inflated is formed with a through hole 48A penetrating in the vertical direction. The through hole 48A is surrounded by the member of the shielding bag 48, and the water in the shielding bag 48 does not flow into the through hole 48A. The through-hole 48A is sealed by a shielding bag 48 that is filled with water and expanded.

  The radiation shield 59 covering the upper part of the reactor well 25 is folded by the above-described driving device and removed from the floor member 58 using the overhead crane 50A. After that, the suspension balance 66 is suspended from the overhead crane 50A, lowered from the space 53A toward the reactor well 25, and opened between the isolation sheets 54 opened and opened and through the opening 58A. Is lowered into. As the suspension balance 66 is lowered, the grippers 67A and 67B and the suspension rods 68A and 68B are inserted into the through holes 48A formed in the respective shielding bags 48 filled with water (see FIG. 28). . Then, each hanging tool provided on the top of the storage container head 18 is held by the holding tools 67A and 67B (see FIG. 28).

  Although not shown in FIGS. 27 and 28, a cylinder device (not shown) having a piston that moves pneumatically is provided on the outer periphery of the suspension balance 66. Three or more cylinder devices are provided in the circumferential direction of the suspension balance 66. A support member is attached to the piston rod of each cylinder device. This support member provided for each cylinder device is pushed out of the reactor well 25 by the supply of high-pressure air to the cylinder device after the suspension balance 66 passes through the opening 58A, and the shield plug It reaches on the stepped portion of the reactor well 25 supporting the 28. For this reason, as shown in FIG. 28, the suspension balance 66 is supported by the step part of the reactor well 25 by these support members.

  Thereafter, the telescopic tube 77 is extended downward, and the cutting machine 69 is lowered to the cutting position of the side wall of the storage container head 18 (position at the lower end of the storage container head 18) (see FIG. 28). The telescopic tube 77 is located outside the shielding bag 48 filled with water. When the moving device 78 moves along the above-described ring-shaped guide rail provided on the suspension balance 66, the lower end portion of the side wall of the storage container head 18 is entirely removed from the side wall of the storage container head 18 by the cutting machine 69. It is cut over the circumference. After the storage container head 18 is cut, the cut storage container head 18 is pulled up by the overhead crane 50 </ b> A with the shielding bag 48 filled with water placed thereon. When a predetermined space is formed between the lower end of the storage container head 18 and the top of the heat insulating material 30 because the lower end of the storage container head 18 reaches above the top of the heat insulating material 30 covering the pressure container head 4. The raising of the storage container head 18 is stopped (see FIG. 29).

  Another isolation chamber 40 in which the decontamination device 71 is housed is carried into the radiation shielding container 32 through the opening 36A, as in the step S2. The decontamination device 71 includes an extendable tube 71B and a work arm 71C attached to the upper end of the support member 42. The injection nozzle 71D is attached to the tip of the work arm 71C. As described above, the isolation chamber 40 has the opening 40E that is opened and closed by the door 40B. After the isolation chamber 40 is moved to the vicinity of the side wall 63, the doors 40B, 64A, and 64B are moved, and the openings 40E and 63A are opened.

  The telescopic tube 71B is extended toward the reactor well 25 through the openings 40E and 63A, and the working arm 71C and the injection nozzle 71D reach between the lower end of the containment vessel head 18 and the top of the heat insulating material 30 in the reactor well 25. . The work arm 71C is operated so that the ejection port of the ejection nozzle 71D faces the inner surface of the storage container head 18. Water is ejected from the ejection nozzle 71D, and the inner surface of the storage container head 18 is decontaminated while operating the telescopic tube 71B and the work arm 71C (see FIG. 29). Further, the surface of the heat insulating material 30 is decontaminated with water sprayed from the spray nozzle 71D. The cleaning water sprayed from the spray nozzle 71 </ b> D falls on the baffle plate 76 while cleaning the inner surface of the storage container head 18 and the surface of the heat insulating material 30, and accumulates on the baffle plate 76. As described above, the water accumulated on the baffle plate 76 is collected in a drain tank in the isolation chamber 40 using a pump and a drain hose.

  After the decontamination of the storage container head 18 or the like is completed, the work arm 71C and the injection nozzle 71D of the decontamination apparatus 71 are housed in the isolation chamber 40, and the doors 40B, 64A, and 64B are closed. The isolation chamber 40 containing the decontamination apparatus 71 is suspended from the overhead crane 50B, pulled up to the space 53B, moved to the operation floor 24 outside the isolation house 49, and then transported to the ground by the crawler crane. .

  The decontaminated storage container head 18 is moved to the space 53A by the overhead crane 50A. Thereafter, a plurality of radiation shields 59 are detachably installed on the bottom surface of the space 53A in the isolation house 49 so as to cover the reactor well 25 as in step S9 (see FIG. 30). Water in each shielding bag 48 covering the storage container head 18 is discharged into the space 53A (see FIG. 30). In the space 53A, the cut storage container head 18 and the suspension balance 66 are wrapped with the isolation film 54 (see FIG. 30), and the wrapped isolation film 54 is welded, and the isolation film 54 is cut at the welded portion. The storage container head 18 and the suspension balance 66 wrapped in the isolation film 54 are transferred into the space 53B through the opening 60A, and further transferred onto the operation floor 24 outside the isolation house 49 and lowered to the ground.

  Next, the removal and carry-out of the heat insulating material 30 which is equipment arranged in the reactor well 25 will be described. For removing and carrying out the heat insulating material 30, a radiation shielding suspension balance device 74 for the heat insulating material 30 as shown in FIG. 54 is used instead of the suspension balance 66.

  The detailed structure of the radiation shielding suspension balance device 74 will be described with reference to FIG. The radiation shielding suspension balance device 74 includes a radiation shielding cover 74A, grips 75C and 75D, and a cutting machine 125. The radiation shielding cover 74A includes a ceiling portion 74B and a cylindrical side wall portion 74C attached to the ceiling portion 74B. The ceiling portion 74B and the cylindrical side wall portion 74C of the radiation shielding cover 74A are respectively spaces, and these spaces are filled with water. By filling each space with water, the radiation shielding cover 74A has a radiation shielding function. The cutting machine 125 is movably attached to a ring-shaped guide rail (not shown) attached to the lower surface of the cylindrical side wall portion 74C. Since the horizontal width of the heat insulating material 30 is smaller than the outer diameter of the storage container head 18, the inner diameter of the cylindrical side wall 74C in the radiation shielding suspension balance 74 for the heat insulating material 30 is as shown in FIG. 18 is smaller than the inner diameter of the cylindrical side wall portion 74C in the radiation shielding suspension balance device 74.

  The radiation shielding suspension balance device 74 is carried into the space 53A and is suspended from the overhead crane 50A as shown in FIG. After that, the radiation shielding suspension balance device 74 is suspended from the overhead crane 50A, lowered toward the reactor well 25 from the space 53A, and passed through the isolation sheet 54 that is opened and closed and opened in the reactor well 25. Is lowered. Further, the radiation shielding suspension balance 74 is lowered until the lower surface of the cylindrical side wall portion 74C reaches the vicinity of the baffle plate 76, and the heat insulating material 30 is inserted into the cylindrical side wall portion 74C. At this time, each of the gripping tools 75C and 75D grips a pair of suspension tools (not shown) provided on the top of the heat insulating material 30. The heat insulating material 30 is covered with a radiation shielding suspension balance device 74. The cutting machine 125 cuts the heat insulating material 30 in the vicinity of the baffle plate 76 while moving along a ring-shaped guide rail attached to the lower surface of the cylindrical side wall portion 74C of the radiation shielding suspension balance device 74. When the cutting machine 125 goes around the ring-shaped guide rail, the lower end portion of the heat insulating material 30 is completely cut.

  Since the radiation shielding suspension balance device 74 covers the heat insulating material 30 while the heat insulating material 30 is cut, the radiation radiated upward from the reactor pressure vessel 3 is filled with water. The suspension balance 74 is shielded. For this reason, the dose in the spaces 53A and 53B can be reduced.

  After the cut heat insulating material 30 is moved to the space 53A by the overhead crane 50A, the heat insulating material 30 and the radiation shielding suspension balance device 74 are wrapped with the isolation film 54, and the wrapped and squeezed isolation film 54 is welded and the welded part Then, the isolation film 54 is cut. The heat insulating material 30 and the radiation shielding suspension balance device 74 encased in the isolation film 54 are transferred into the space 53B through the opening 60A, and further transferred to the operation floor 24 outside the isolation house 49 and lowered to the ground. .

  Thus, the removal and unloading of the equipment in the reactor well in step S10 are completed.

  Removal of the baffle plate and attachment of the pressure vessel support beam and the radiation shielding plate are performed (step S11). In the process of step S11, a suspension balance device 127 is used. The suspension balance device 127 includes the radiation shielding suspension balance device 74 and the suspension balance 66 described above. The suspension balance 66 is suspended by the radiation shielding suspension balance device 74. The suspension balance 66 is disposed in the cylindrical side wall portion 74C below the ceiling portion 74B, and each of a pair of suspension devices provided on the upper surface of the suspension balance 66 is provided in the radiation shielding suspension balance device 74. It is gripped by the gripping tool 75C of 75A and the gripping tool 75D of the suspension device 75B. The suspension balance 66 is attached with a suspension device 66A with a gripping tool 67A attached at the lower end and a suspension device 66B with a gripping tool 67B attached at the lower end.

  The suspension balance device 127 is carried into the space 53A from the outside of the isolation house 49 via the space 53B and is suspended by the overhead crane 50A. Similar to the radiation shielding suspension balance device 74 in step S10, the suspension balance device 127 is lowered to the reactor well 25 by the overhead crane 50A until the lower surface of the cylindrical side wall 74C reaches the vicinity of the baffle plate 76 (FIG. 31). At this time, the radiation shielding suspension balance device 74 covers the pressure vessel head 4 in the reactor well 25.

  In the state where the suspension balance device 127 is disposed in the reactor well 25 as shown in FIG. 31, the carried-in isolation chamber 40 containing the radiation shielding plate 79 and the support beam member 80 is not shown. It is carried into the shielding container 32. In the isolation chamber 40, a telescopic tube and a gripping device (not shown) in which a gripping tool is attached to the distal end of the telescopic tube are housed. With this gripping tool, the radiation shielding plate 79 is gripped, the doors 64A and 64B in the isolation chamber 40 are opened, the telescopic tube of the gripping device is extended, and the gripping tool gripping the radiation shielding plate 79 is baffled in the reactor well 25. Move to above 76. The radiation shielding plate 79 is placed on the baffle plate 76. The support beam member 80 in the isolation chamber 40 is also gripped by the gripper and similarly transferred into the dry well 25 and placed on the baffle plate 76.

  A part of the installed baffle plate 76 is gripped by the gripping tool 67B and removed (see FIG. 31). The radiation shielding plate 79 on the installed baffle plate 76 is grasped by the gripper 67B and lowered to the area between the reactor pressure vessel 3 and the reactor containment vessel 17, and the reactor pressure vessel 3 and the atom It is attached to the furnace containment vessel 17 (see FIG. 32). The other baffle plate 76 is also gripped by the gripping tool 67A and removed. Each removed baffle plate 76 is gripped by a gripping tool of a gripping device in the isolation chamber 40, transferred into the isolation chamber 40, and stored in the isolation chamber 40. The radiation shielding plate 79 gripped by the gripping tool 67A is lowered to the region between the reactor pressure vessel 3 and the reactor containment vessel 17 at the position of the baffle plate 76 gripped by the gripping tool 67A and removed. A radiation shielding plate 79 is attached to the reactor pressure vessel 3 and the reactor containment vessel 17 (see FIG. 33). Further, the support beam member 80 on the installed baffle plate 76 is lowered by being grasped by the gripper 67B, and is installed on the reactor pressure vessel 3 and the biological shield 100 above the radiation shielding plate 79 (see FIG. 33). At the position of the baffle plate 76 gripped by the gripping tool 67A, the support beam member 80 gripped by the gripping tool 67A is lowered, and the support beam member 80 is positioned above the radiation shielding plate 79 and the reactor pressure vessel 3. And it installs in the biological shield 100 (refer FIG. 34).

  A plurality of radiation shielding plates 79 disposed in the region between the reactor pressure vessel 3 and the containment vessel 17 and attached to the reactor pressure vessel 3 and the reactor containment vessel 17 are connected to the reactor pressure vessel 3 and the reactor. The region between the containment vessels 17 is sealed, and the radiation from the reactor containment vessel 17 toward the reactor well 25 is shielded, and further, the rise of radioactive dust from the reactor containment vessel 17 toward the reactor well 25 is prevented. To do. A plurality of support beam members 80 disposed in the region between the reactor pressure vessel 3 and the biological shield 100 and attached to the reactor pressure vessel 3 and the biological shield 100 are composed of the reactor pressure vessel 3 and the biological shield 100. And the reactor pressure vessel 3 is supported from the biological shield 100. This is intended to prevent the reactor pressure vessel 3 from falling down as a countermeasure in the event that the strength of the concrete support of the pedestal 15 that supports the reactor pressure vessel 3 is impaired.

  An isolation container is installed (step S12). After the step S11 is completed, the isolation container 81 is disposed from the reactor well 25 to the space 53A (see FIG. 35). The configuration of the isolation container 81 will be described with reference to FIG. The isolation container 81 includes 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 with a cover member 81D that is a disk. A lower cylindrical member 81 </ b> C in which a shielding bag 86 is installed is installed on the support beam member 80 in the reactor well 25. An intermediate cylindrical member 81B in which a shielding bag 85 is installed is placed on the upper end of the lower cylindrical member 81C and coupled to the lower cylindrical member 81C. An upper cylindrical member 81A in which a holding member 82 and a supporting member 82A are disposed and sealed with a cover member 81D is placed on the upper end of the intermediate cylindrical member 81B and coupled to the intermediate cylindrical member 81B. A radiation shielding plate 91 in which an opening through which the intermediate cylindrical member 81B passes is formed on the floor member 58, and the radiation shielding plate 91 has an opening 58A formed in the floor member 58 except for the portion of the intermediate cylindrical member 81B. Covering.

  Further, a carry-in / out air lock 89 is disposed in the reactor well 25, and one end of the carry-in / out air lock 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 air lock 89 on the radiation shielding container 32 side. The other end of the carry-in / out air lock 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 air lock 89 on the lower cylindrical member 81C side. The space 89C in the carry-in / out air lock 89 communicates with the inside of the radiation shielding container 32 by opening the opening / closing door 89A, and communicates with the inside of the lower cylindrical member 81C by opening the opening / closing door 89B.

  The carry-in / out air lock 90 is disposed on the radiation shielding plate 91 in the space 53A, and one end of the carry-in / out air lock 90 is attached to the intermediate cylindrical member 81B. An open / close door 90A is attached to one end of the carry-in / out air lock 90 on the intermediate cylindrical member 81B side. An opening / closing door 890 </ b> B is attached to the other end of the carry-in / out air lock 90. The space 90C in the carry-in / out air lock 90 communicates with the intermediate cylindrical member 81B by opening the opening / closing door 90A, and communicates with 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 air lock 89, and a watering device (not shown) is installed near the top of the inner surface of the carry-in / out air lock 90. Further, the carry-in / out air lock 89 is provided with an air exchange device (not shown) that exchanges air in the space 89C, and the carry-in / out air lock 90 also exchanges air in the space 90C (not shown). 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 the open / close door 89A of the carry-in / out air lock 89 and the open / close door 90A of the carry-in / out air lock 90 are combined. Are attached, the sealed space 93 is formed in the isolation container 81 formed by combining the upper cylindrical member 81A, the intermediate cylindrical member 81B, and the lower cylindrical member 81C.

  The intermediate cylindrical member 81B and the lower cylindrical member 81C are 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 it is easy to carry the intermediate cylindrical member 81B and the lower cylindrical member 81C into the reactor well 25 and the space 53A. It is. Water is supplied into the shielding bags 85 and 86 using a water supply hose connected to a makeup water system existing outside the isolation house 49 after the isolation container 81 is assembled in the reactor well 25 and the space 53A. Done. Each of the shielding bags 85 and 86 filled with water is a radiation shielding body. The shielding bag 85 filled with water is disposed in the isolation container 81 so as to face the opening / closing door 90A of the carry-in / out air lock 90, and the shielding bag 86 filled with water is carried out in the isolation container 81. The pressure vessel head 4 is disposed so as to face the open / close door 89 </ b> B of the inlet air lock 89. Similar to the shielding bag 48, through holes 85A and 86A are formed in the shielding bags 85 and 86, respectively, filled with water. The through hole 85A is surrounded by the member of the shielding bag 85, and the water in the shielding bag 85 does not flow into the through hole 85A. The through-hole 85A is sealed by a shielding bag 85 that is filled with water and expanded. The through-hole 86A of the shielding bag 86 has a similar structure.

  A rod-like support member 82A is disposed 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. An isolation sheet 84 is attached to the lower end of the upper cylindrical member 81A and isolates the space in the upper cylindrical member 81A from the space in the intermediate cylindrical member 81B. The lifting device (for example, hoist) 83 is held by the holding member 82 by the wire 128. The wire 128 passes through the isolation sheet 84, and the wire 128 and the isolation sheet 84 are sealed in order to maintain airtightness. This isolation sheet is folded in a bellows shape, and has a structure that can expand and contract 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, in order to remove the pressure vessel head 4 from the reactor pressure vessel 3, it is necessary to remove those bolts. An outline of removing these bolts will be described. A stat bolt tensioner is used to remove these bolts. Although not shown, an isolation chamber 40 containing a stat bolt tensioner, a pair of half guide rails, and a manipulator device (not shown) is opened and closed through the opening 36A and the space 37 in the radiation shielding container 32. By opening the door 89 </ b> A, it is carried into the space 89 </ b> C in the carry-in / out air lock 89. At this time, the open / close door 89B is closed. The manipulator device has substantially the same configuration as the shielding body transport device 47 used in step S5. The manipulator device includes a slide mechanism 45B attached to the upper end portion of the support member 42, a telescopic tube 45A, and an articulated work arm 45C. A gripping tool 47A is attached to the tip of the work arm 45C.

  After gripping one half of the guide rail in the isolation chamber 40 with the gripping tool 47A, the open / close door 89B is opened, and the sliding mechanism 45B and the telescopic tube 45A are shielded with water in the lower cylindrical member 81C. Is moved downward. The working arm 45C is bent and extended, and the half of the guide rail gripped by the gripping tool 47A is below the shielding bag 86 and above the flange of the pressure vessel head 4 and 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 opposite to the opening / closing door 89B by 180 °. A plurality of support members are attached to the lower surface of the half guide rail, and the guide rail is supported on the support beam member 80 by these support members. The other half of the 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 and on the opening / closing door 89B side. The two half guide rails are connected to each other. Using the manipulator device, a moving device having a holding portion for the stat bolt tensioner is attached to the guide rail, and the stat bolt tensioner is attached to the holding portion. 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 coupling 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 the manipulator device. Thereafter, the slide mechanism 45B and the telescopic tube 45A are contracted, and the gripping tool 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 exchange device of the carry-in / out air lock 89 discharges the air in the space 89C to the outside and supplies the clean air outside to the space 89C. The air exchange device includes a purification device, and the radioactive substance contained in the air discharged from the space 89C is removed by the purification device. Water is applied to the isolation chamber 40 from the watering device in the carry-in / out air lock 90 to wash away the adhering radioactive material. This water is discharged to a drainage device provided in the carry-in / out air lock 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, and after closing the opening / closing door 89A, the isolation chamber 40 is transferred out of the isolation house 49 through the opening 36A and the like.

  While the bolts connecting the pressure vessel head 4 and the reactor pressure vessel 3 are being removed, a gripping tool (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 shielding bag 85 filled with water and the through hole 86A of the shielding bag 86 filled with water, and is attached to the wire 87. The tool grips a 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 lifting and lowering device 83 is driven to wind the wire 87, whereby the pressure vessel head 4 is raised and the shielding bag 86 filled with water is filled. Is inserted into the through hole 86A (see FIG. 36). As the pressure vessel head 4 moves up in the through hole 86 </ b> A, the water existing above the pressure vessel head 4 in the shielding bag 86 moves below the pressure vessel head 4 in the shielding bag 86. For this reason, the pressure vessel head 4 can easily rise in the through hole 86 </ b> A of the shielding bag 86 filled with water, and the position of the lower end of the shielding bag 86 is lowered to the vicinity of the upper end of the steam dryer 12. The shielding bag 86 filled with water shields radiation from inside 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 to the space between the shielding bag 85 and the shielding bag 86, the inner surface (lower surface) of the pressure vessel head 4 is decontaminated. (See FIG. 37). Similarly to the decontamination of the inner surface of the storage container head 18 shown in FIG. 29, the isolation chamber 40 containing the decontamination device 71 is carried into the radiation shielding container 32 through the opening 36A, and is further opened and closed. 89A is opened and moved into the space 89C in the carry-in / out air lock 89. The opening / closing door 89A is closed, and the upper end portion which is a part of the opening / closing door 89B is opened. The telescopic tube 71 </ b> B of the decontamination device 71 is inserted in the space 93 between the pressure vessel head 4 and the shielding bag 86. The work arm 71C is operated so that the spray nozzle 71D is opposed to the inner surface of the pressure vessel head 4, and water is sprayed from the spray nozzle 71D. The inner surface of the pressure vessel head 4 is decontaminated by operating the telescopic tube 71B and the work arm 71C while jetting water from the jet nozzle 71D (see FIG. 37). The water that falls upon hitting the inner surface of the pressure vessel head 4 is received by a washing water tray (not shown) attached to the work arm 71C, and is collected in the 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 up to an upper position considering the space in which the decontamination device 71 can be inserted from the upper end of the dryer 12, the work arm 71C is set on the lower surface and the injection nozzle 71D Decontaminate. Thereafter, it passes through the shielding bag 86 and is pulled up. After the decontamination of the inner surface of the pressure vessel head 4 is completed, the telescopic tube 71B, the work arm 71C, and the injection nozzle 71D are accommodated in the isolation chamber 40, and the open / close door 89B is completely closed. The isolation chamber 40 is transported from the space 89C in the carry-in / out air lock 89 to the ground through the opening 36A.

  A part of the water in the shielding bag 85 is discharged, and the thickness of the shielding bag 85 is reduced 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 open / close door 90A (see FIG. 38). Thereafter, 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. There is a possibility that a radioactive substance flows into the space 89C by opening the open / close door 90A. For this reason, the air exchange device of the carry-in / out air lock 90 discharges the air in the space 90C to the outside and supplies clean air outside to the space 90C. The air exchange device includes a purification device, and 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 again applied to the pressure vessel head 4 from the watering device in the carry-in / out airlock 90, and the pressure vessel head 4 is attached. Wash away radioactive material. This water is discharged to a drainage device provided in the carry-in / out air lock 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 open / close door 90B is closed.

  In this embodiment, the isolation vessel 81 is disposed in the space 53A in the reactor well 25 and the isolation house 49 so as to cover the pressure vessel head 4, and the reactor is opened by removing the pressure vessel head 4 to reduce the internal volume. Since the radioactive substance is released from the reactor pressure vessel 3 from which the pressure vessel head 4 has been removed because the operation is performed in the isolation vessel 81, the region contaminated by the radioactive material is limited in the isolation vessel 81, It is possible to prevent the nuclear reactor well 25 and the isolation house 49 having a large volume from being contaminated by the radioactive material.

  Since the shielding bags 85 and 86 filled with water are disposed in the isolation container 81, the radiation radiated from the reactor pressure vessel 3 can be shielded by the shielding bags 85 and 86. For this reason, the dose in the isolation house 49, for example, the dose in the space 53A, is not affected by the radiation from the reactor pressure vessel 3, and can be suppressed to a low value. The exposure of workers who work in the space 53A can be significantly reduced.

  Since the equipment (for example, the pressure vessel head 4) in the isolation container 81 is carried out of the isolation container 81 and the articles are carried into the isolation container 81, the isolation containers are used. The release of air containing radioactive material in 81 to the outside environment can be prevented. In particular, since each of the carry-in / out air locks 89 and 90 includes the watering device and the air exchange device, it is possible to prevent the radioactive material from being released to the external environment.

  Thus, the reactor opening operation in the method for opening the reactor pressure vessel is completed, and all the steps of the method for opening the reactor pressure vessel are completed.

  Each process other than each process of the method for opening the reactor pressure vessel described above in the fuel debris retrieval method will be described below with reference to FIG. These steps include the steps of taking out fuel debris that has fallen to the bottom of the reactor containment vessel and taking out fuel debris in the reactor. Steps S17 to S20 relating to the removal operation of the fuel debris that has fallen to the bottom of the reactor containment vessel and steps S21 and S22 of the removal operation of the fuel debris in the reactor are taken out of the fuel debris in the reactor. The operation must be completed before the process of step S15 (formation of a through hole in the lower mirror portion of the reactor pressure vessel 3) is started. For this reason, the operation of taking out the fuel debris that has fallen to the bottom of the reactor containment vessel is performed in parallel with the aforementioned reactor opening operation. Further, in some cases, the operation of step S17 for extracting the fuel debris that has fallen to the bottom of the reactor containment vessel must be started in the preparation operation before the reactor opening operation.

  The operation for removing fuel debris that has fallen to the bottom of the reactor containment vessel will be described. In this fuel debris retrieval operation, the construction of the first radiation shielding chamber described in JP-A-2014-70946 (step S1), the movement of the drilling device into the first radiation shielding chamber (step S2), and atoms Formation of the opening part (step S3) which penetrated to the side wall of the furnace building 23 is implemented sequentially.

  Thereafter, the interference in the reactor building in the present embodiment shown in FIG. 4 is removed (step S17). In the process of step S17, the same operation as the operation of removing the interference in the reactor building (step S4) described in paragraphs 0031 and 0032 of JP 2014-70946 A is performed. A work house 101 (corresponding to the second radiation shielding chamber 47 and the room 48 described in Japanese Patent Application Laid-Open No. 2014-70946) facing the control rod drive mechanism hatch 104 (see FIG. 47) formed on the biological shielding body 100 is provided. Interfering substances that obstruct the assembly in the reactor building 23 are removed using an interference removing apparatus described in Japanese Patent Application Laid-Open No. 2014-70946. The storage container storing the removed interference is transferred to a predetermined area in the radioactive waste processing building, for example (paragraph 0033).

  A work house is installed in the reactor building (step S18). In the process of step S18 of this embodiment, each operation described in paragraphs 0034 to 0040 of JP 2014-70946 A is performed, and the work house 101 is installed in the reactor building 23. The work house 101 installed in step S18 of the present embodiment will be described with reference to FIG. The work house 101 is constructed using an iron plate that is a radiation shielding material. A work house 101 having spaces 101 </ b> A and 101 </ b> B therein is constructed in the vicinity of the control rod drive mechanism hatch 104 formed in the biological shield 100 in the reactor building 23. The work house 101 is composed of two radiation shielding bodies (not shown) made of iron plates on opposite side walls, a radiation shielding body 101F made of iron plates on the ceiling, and a radiation shielding body (not shown) made of iron plates on the floor. These radiation shields are joined together. Spaces 101 </ b> A and 101 </ b> B are formed by partitioning an inner region surrounded by these radiation shielding bodies with a radiation shielding body 101 </ b> D that is an iron plate having an opening formed in a lower portion. The radiation shielding body 101D faces the outer surface of the biological shielding wall 100, and is joined to each radiation shielding body that becomes both side walls, a ceiling, and a floor by welding. A carry-in / out air lock 101E provided with a decontamination device (not shown) is attached to the opening of the radiation shielding body 101D. The carry-in / out air lock 101E is provided with an open / close door (not shown) at each end of the spaces 101A and 101B. A radiation shielding body 101C, which is an iron plate, is arranged facing the radiation shielding body 101D, and the radiation shielding body 101C is joined to each radiation shielding body to which the radiation shielding body 101D is attached by welding.

  A space 101B communicated with the control rod drive mechanism hatch 104 is formed between the radiation shielding body 101D and the biological shielding wall 100, and a space 101A is formed between the radiation shielding body 101D and the radiation shielding body 101C. A transport device 102 including a guide rail 102A and a suspension device 102B that moves along the guide rail 102A is installed in the space 101A in the vicinity of the radiation shield 101F. A guide rail 102A is attached to the radiation shielding bodies 101C and 101D. A conveyance device 103 including a guide rail 103A and a suspension device 103B that moves along the guide rail 103A is installed in the space 101B in the vicinity of the radiation shielding body 101F. The guide rail 103A is attached to the radiation shielding body 101C and the biological shielding wall 100. An access passage described in Japanese Patent Laid-Open No. 2014-70946 is connected to the radiation shield 101C (see paragraph 0040).

  An access route in the reactor containment vessel is secured (step S19). In the process of step S19 of the present embodiment, the articulated access device described in Japanese Patent Application Laid-Open No. 2014-70946 is moved to the space 101B through the access path. The articulated arm of this articulated access device is inserted into the reactor containment vessel 17 through the control rod drive mechanism hatch 104. Falling objects (part of equipment and heat insulating materials, etc.) scattered in the region where the transfer device 106 (see FIG. 47) in the reactor containment vessel 17 is installed using a gripping tool attached to the tip of the articulated arm. Then, the interference that hinders the operation of the multi-joint arm in the reactor containment vessel 17 and the interference that disturbs the installation of the transfer device 106 shown in FIG. 47 in the reactor containment vessel 17 are removed. A fallen object or an interference object is grasped by a gripping tool attached to the articulated arm, taken out into the space 101B, and stored in the transport container 113. The transport container 113 is transferred to a predetermined area in the radioactive waste disposal building through the access passage via the carry-in / out air lock 101E and the space 101A. In this way, all fallen objects existing in that region of the transfer device 106 in the reactor containment vessel 17 are transferred to the predetermined region.

  The fuel debris that has fallen to the bottom of the reactor containment vessel in the pedestal is taken out (step S20). Pedestal openings formed in the control rod drive mechanism hatch 104 and the pedestal 15 by alternately attaching a crusher and a gripper to the tip of the articulated arm of the articulated access device existing in the space 101B. Each of 105 is inserted into lower plenum 20. The fuel debris 39B (see FIG. 1) that has fallen to the bottom of the reactor containment vessel 17 in the lower plenum 20 is crushed by a crusher attached to the tip of the articulated arm. After the fuel debris 39B is crushed to some extent, the crusher attached to the tip of the articulated arm is replaced with a gripping tool, and the crushed piece of the fuel debris 39B is gripped by this gripping tool, and this crushed piece is transferred from the lower plenum 20 to the space 101B. Take out and store in the transport container 113 in the space 101B. The transport container 113 in which the fragments of the fuel debris 39B are stored is transported to a predetermined storage area through the transport-in / out air lock 101E, the space 101A, and the above-described access passage. The removal of the fuel debris 39B that has dropped onto the bottom of the reactor containment vessel 17 in step S20 is specifically described in paragraphs 0046 to 0054 of JP-A-2014-70946.

  Thus, the operation for removing the fuel debris that has fallen to the bottom of the reactor containment vessel is completed. In this fuel debris retrieval operation, each effect produced in Example 1 of Japanese Patent Application Laid-Open No. 2014-70946 can be obtained. Thereafter, the fuel debris removal work in the reactor is started.

  After the process of step S20 is complete | finished, a conveying apparatus is installed in a nuclear reactor containment vessel (step S21). In step S21, the transfer device 106 shown in FIG. 47 is installed outside the pedestal 15 in the reactor containment vessel 17 from which the fallen objects and interferences have been removed in step S19.

  As shown in FIG. 47, the transport device 106 includes a plurality of connecting members 106A, at least four columns 106C, a guide rail 160D, and a suspension device 106B. Each column 106 </ b> C is installed on a horizontal beam 133 disposed in the reactor containment vessel 17 near the control rod drive mechanism hatch 104 and the pedestal opening 105. The upper ends of the columns 106C are coupled to each other by a plurality of connecting members 106A. The guide rail 160D is attached to one connecting member 10A, and the suspension device 106B is movably attached to the guide rail 160D. Such assembly of the transfer device 106 in the reactor containment vessel 17 is performed by using an articulated access device existing in the space 101B. The belt conveyor 112 is installed in the control rod drive mechanism hatch 104, and extends from the installation location of the transfer device 106 in the reactor containment vessel 17 to the space 101B.

  A shock absorber and a carry-out device are installed (step S22). The shock absorber 109 is grasped by using a gripping tool attached to the tip of the multi-joint arm of the multi-joint access device existing in the space 101B, and the shock absorber 109 is operated by operating the multi-joint arm to control rod drive mechanism hatch 104 and pedestal. It is carried into the lower plenum 20 through the opening 105. The buffer device 109 is a bag for injecting water, and the bag is not filled with water when it is carried into the lower plenum 20. Since the water is not filled, the buffer device 109 can be easily carried into the lower plenum 20. After the shock absorber 109 is carried into the lower plenum 20, the shock absorber 109, that is, the bag is filled with water. As a result, the shock absorber 109 filled with water is installed at the bottom of the reactor containment vessel 17 in the lower plenum 20 as shown in FIG. An inclined surface 107 that is inclined toward the pedestal opening 105 is formed on the upper surface of the shock absorber 109 filled with water.

  An unloading device 116 is installed in the reactor containment vessel 17 on the outer surface side of the pedestal 15 in the vicinity of the pedestal opening 105 (see FIGS. 47 and 48). The carry-out device 116 includes a support member 110, a cart 114, branch carts 115 </ b> A to 115 </ b> C, and a storage container cradle 119. The cart 114 is disposed in a pedestal opening 105 formed in the pedestal 15 and attached to the pedestal 15. The cart 114 is inclined at the same angle as the inclined surface 107 from the lower plenum 20 toward the outside of the pedestal 15. Each of the branch carts 115 </ b> A to 115 </ b> C is disposed inside the reactor containment vessel 17 outside the pedestal 15, and is installed at the distal end portion of the cart 114 so as to be rotatable and bent. Openable / closable shutters (not shown) are attached to the outlets of the branch carts 115A to 115C, and the shutters open and close the outlets of the branch carts 115A to 115C. A plate-like support member 110 is attached to the outer surface of the pedestal 15 below the pedestal opening 105. A storage container cradle 119 on which the storage container 111 is placed is attached to the upper surface of the support member 110 via a spring 120. In the carry-out device 116, pulleys 117A and 117B are rotatably attached to the lower surface of a support member attached to the tip portion of the cart 114. A wire 118 is hung on the pulleys 117A and 117B, and one end of the wire 118 is stored. The other end of the wire 118 is attached to the branch cart 115A. The pulleys 117A and 117B, the wires 118, the storage container cradle 119, and the spring 120 are similarly provided for the branch carts 115B and 115C, respectively. The storage container cradle 119 is disposed directly under the outlet of each of the branch carts 115A to 115C. The carry-out device 116 is assembled using an articulated access device existing in the space 101 </ b> B, similarly to the transfer device 106, and arranged so that the transfer of the storage container 11 is entrusted to the transfer device 106.

  A pair of opposing guide members are arranged on the inclined surface 107 of the shock absorber 109 so that the width gradually decreases toward the pedestal opening 105. By installation of these guide members, the cut pieces of the reactor internal structure dropped on the inclined surface from the reactor pressure vessel 3 are smoothly moved to the cart 114.

  Next, taking out of 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 removed (step S14). First, taking out of the steam dryer 12 when the steam dryer 12 can be easily detached from the reactor pressure vessel 3 will be described with reference to FIGS. 39 to 41.

  Although not shown in FIG. 39, the manipulator device used in step S13 and the isolation chamber 40 containing the suspension balance 92 are carried into the space 37 in the radiation shielding container 32 through the opening 36A, and further opened and closed. The door 89 </ b> A is opened and transferred into the carry-in / out air lock 89. After the isolation chamber 40 is transferred into the carry-in / out air lock 89, the door 89A is closed and the door 89B is opened. The suspension balance 92 in the isolation chamber 40 is gripped by the gripper 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 the suspension balance 92 is placed on the steam dryer 12, the gripping tool 47A is separated from the suspension balance 92, and the lifting tool of the suspension balance 92 is grasped and lifted by the gripping tool 47A. A gripping tool attached to a wire 87 connected to the lifting device 83 grips the lifting tool of the lifting balance 92.

  After the working arm 45C and the gripping tool 47A of the manipulator device are accommodated 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 changer, and the carry-in / out air lock In 89, the water sprayed from the water sprinkler is hung on the outer surface of the isolation chamber 40, and the attached radionuclide is washed away. 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 conveyed to the ground through the opening 36A.

  After the steam dryer 12 is removed from the reactor pressure vessel 3, the elevating device 83 is driven to wind the wire 87 (see FIG. 39). 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 air lock 89, the rise of the steam dryer 12 is stopped and the open / close doors 89A and 89B are opened. The slidable carriage 92 that 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 81 </ b> C through the carry-in / out air lock 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. 40). Since the open / close doors 89 </ b> A and 89 </ b> B are open, the radionuclide in the lower cylindrical member 81 </ b> C may diffuse into the carry-in / out air lock 89 and the radiation shielding container 32.

  By moving the sliding carriage 92, the steam dryer 12 is transferred to the space 37 in the radiation shielding container 32 through the carry-in / out air lock 89 (see FIG. 40). The open / close doors 89A and 89B are closed. As described above, the air in the space 89C in the carry-in / out air lock 89 is replaced, and the inside of the carry-in / out air lock 89 is washed by watering. 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 exchange 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 open / close doors 89A and 89B are closed, the air in the radiation shielding container 32 is replaced with clean air by the air exchange device. The steam dryer 12 and the sliding carriage 92 in the radiation shielding container 32 are washed by the water jetted. The steam dryer 12 and the sliding carriage 92 of the radiation shielding container 32 are conveyed to the ground through the opening 36A.

  Similarly to the steam dryer 12, the steam 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 conveyed to the ground through the opening 36A.

  When 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. 42 is taken out as an alternative to taking out the steam dryer 12 described above. The 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.

  The dismantling device 94 is carried into the lower cylindrical member 81 </ b> C through the carry-in / out air lock 89 from the space 37 in the radiation shielding container 32. The door 34 of the radiation shielding container 32 is closed. The above-mentioned manipulator device is used for this carry-in. The dismantling device 94 is suspended from the gripping tool of the lifting device 83 and is installed on the upper flange of the reactor pressure vessel 3.

  The configuration of the dismantling device 94 will be described below. The disassembling apparatus 94 has four support columns 94B, and these support columns 94B are connected to each other by four connecting members 94A arranged in the horizontal direction. A multi-joint arm 94C provided with a cutting machine 94D at the tip and a multi-joint 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 cart. Four struts 94 </ b> B are installed on the upper flange of the reactor pressure vessel 3.

  Further, the storage container transport device 95 is carried into the space 89 </ b> C in the carry-in / out air lock 89 from the space 37 in the radiation shielding container 32. The storage container transport device 95 includes a storage portion 95E that also serves as a support member, a pair of support members 95B attached to a horizontal member (not shown) attached to the upper end of the storage portion 95E across the storage portion 95E, and A guide arm 95A 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. A wire 95D is attached to the suspension device 95C, and a suspension tool (not shown) is attached to the wire 95D.

  In the disassembling apparatus 94, the cutting portion of the steam dryer 12 is grasped 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 cutting portion is cut by using a cutting machine 94D for the tip portion. The cut piece of the steam dryer 12 gripped by the gripping tool 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 the inside of the lower cylindrical member 81C. Is stored in a storage container 96 positioned in the position. Cut pieces of the steam dryer 12 that are sequentially generated by cutting by the cutting machine 94D are gripped by the gripping tool 94F and sequentially stored in the storage container 96 suspended by the suspension device 95.

  When the storage container 96 is filled with the cut pieces, the suspension device 95 is moved directly above the storage part 95E to suspend the storage container 96 suspended in the storage part 95E, and the storage part 95E. Store inside. When a predetermined number of storage containers 96 storing the cut pieces of the steam dryer 12 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 air lock 89. It is moved to the space 37 in the container 32. 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 using the suspension device 95C. When the storage container 96 in the storage unit 95E runs out, the storage container transport device 95 is moved again into the carry-in / out air lock 89. The steam dryer 12 is cut in the lower cylindrical member 81C, and the cut piece is 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 work is performed until the cutting of the steam dryer 12 is completed. The transport container cleaned by the sprinkler 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-water separator 11 in the reactor pressure vessel 3 is cut and carried out by the dismantling device 94 and the storage container transport device 95 in the same manner as the steam dryer 12.

  A through hole is formed in the lower mirror part of the reactor pressure vessel (step S15). After the step S22 is completed, the step S15 is started. A boring device 129 is used to form the through hole 129C in the lower mirror part 5 of the reactor pressure vessel 3 (see FIG. 43). As the boring device 129, the boring device described in paragraphs 0034 to 0043 of FIG. A first rotary table (not shown) is rotatably attached to the upper surface of a disk-shaped support device 130A disposed in the reactor pressure vessel 3, and a second rotary table (not shown) is rotated first. Mounted eccentrically on the table. The boring device 129 is installed on the upper surface of the second rotary table. A cylindrical member 130B surrounds the first and second rotary tables and is attached to the upper surface of the support device 130A. A pair of ring-shaped seal members 130C for sealing the outer surface of the cylindrical member 130B and the inner surface of the reactor pressure vessel 3 are attached to the outer surface of the cylindrical member 130B. Water that shields radiation from below is filled inside the cylindrical member 130B on the support device 130A. Seals are provided between the support device 130A and the first rotary table and between the first rotary table and the second rotary table so that the water does not leak.

  A support member 96 is attached to the inner surface of the intermediate cylindrical member 81B, and a pair of winding devices 97A and 97B are installed on the upper surface of the support member 96. The wire 98A taken up by the take-up device 97A and the wire 98B taken up by the take-up device 97B penetrate the through-hole formed in the shielding bag 85 filled with water installed on the inner surface of the lower cylindrical member 81C. Then, it reaches below the shielding bag 85 and is attached to the upper surface of the cylindrical member 130B. Support device 130A is supported by wires 98A and 98B.

  The boring device 129 includes a cutting device 129C, a support stand 129A, a pair of first and second clamping devices (not shown), and an extension pipe supply, as described in paragraph 0034 of JP2013-19855A. A device (not shown) is provided. The support stand 129A is installed on the rotary table. The first clamping device is fixed to the lower end portion of the mast member of the support stand 129A. The second clamping device is attached to a moving table attached to the mast member so as to be movable in the vertical direction. The cutting device 129 </ b> C includes an outer cylinder (outer blade shaft), an outer blade, an inner blade, and a rotating shaft (inner blade shaft) as described in paragraph 0036 of JP2013-19855. The outer cutter is provided at the lower end of the outer cylinder, and the inner cutter is provided at the lower end of the rotating shaft arranged in the outer cylinder. A plurality of extension pipes 129B are sequentially connected to the upper end of the cutting apparatus 129C by the extension pipe supply apparatus, and the cutting apparatus 129C is lowered to the lower mirror portion 5 of the reactor pressure vessel 3. The uppermost extension tube 129B is detachably gripped by a third clamp device rotatably attached to a support member attached to the moving table.

  The third clamp device is rotated by the motor installed on the support member attached to the moving table, and the extension tube 129B is rotated. As a result, the outer cylinder and the rotation shaft of the cutting device 129C are rotated, and the lower mirror portion 5 is cut downward by the outer blade and the inner blade, so that a through hole 132 (see FIG. 47) is formed in the lower mirror portion 5. The When the fuel debris 39A exists on the lower mirror portion 5, the through hole 132 is also formed in the fuel debris 39A. A plurality of through holes 132 are formed through the fuel debris 39 </ b> A and the lower mirror part 5.

  The boring device 129 and the support device 130 </ b> A are taken in and out from the radiation shielding container 32 through the carry-in / out air lock 89.

  The reactor internal structure and fuel debris in the reactor pressure vessel are cut (step S16). As shown in FIG. 44, the in-core structures such as the core shroud 6, the core support plate 9, the upper lattice plate 10, and the control rod guide tube 13 which are the in-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 shielding bag 85 filled with water, and a pair of winding devices 97A and 97B are installed on the upper surface of the support member 96. A wire 98A wound around the winding device 97A and a wire 98B wound around the winding device 97B are attached to the upper end of the main body 99A of the cutting device 99, respectively. The cutting device 99 disposed 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 a carry-in / out air lock 89.

  The configuration of the cutting device 99 will be described with reference to FIGS. 45 and 46. The cutting device 99 includes a main body 99A, a rotating body 99B having a plurality of cutting blades 99C attached to the lower surface, and a suspension 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. In the rotating body 99B, a groove 99E opened downward is formed so as to pass through the rotation center of the rotating body 99B. The suspension head 99D is attached to a moving table 99I which is disposed in the groove 99E and attached to the rotating body 99B so as to be movable in the radial direction. Although not shown, this moving table is provided with a rotating mechanism for rotating the suspension head 99D and a moving mechanism for moving the suspension head 99D in the direction of the rotation axis of the rotating body 99B. A jet nozzle 99F for water jet or abrasive water jet and a laser head 99G are attached to the lower surface of the suspension head 99D.

  The rotary body 99B of the cutting device 99 is rotated in the reactor pressure vessel 3, and the above-described reactor internals are cut by the plurality of cutting blades 99C. Cutting of the furnace internal structure is performed while driving the winding devices 97A and 97B to rewind the wires 98A and 98B and lowering the cutting device 99, respectively. When cutting the in-furnace structure with the cutting blade 99C, the suspension head 99D is present in the groove 99E so as to be positioned above the lower surface of the rotating body 99B. A cut piece of the reactor internal structure generated by cutting with the cutting blade 99C falls in the reactor pressure vessel 3 toward the lower mirror part 5.

  The reactor internal structure piece and the fuel debris piece are each carried out from the reactor pressure vessel to the lower plenum (step S23). The cut pieces of the in-furnace structure dropped further onto the inclined surface 107 of the shock absorber 109 in the lower plenum 20 inside the pedestal 15 from the plurality of through holes 132 formed in the lower mirror part 5. In this way, the cut pieces of the reactor internal structure are carried out of the reactor pressure vessel 3.

  Each of the in-furnace structure piece and the fuel debris piece is carried out of the pedestal (step S24). The cutting piece that has fallen on the inclined surface 107 slides on the inclined surface 107 and moves toward the pedestal opening 105. As needed, the cutting piece dropped on the inclined surface 107 is pushed out toward the pedestal opening 105 side by the shovel traveling device 108 traveling on the inclined surface 107. A cut piece of the in-furnace structure that slides on the inclined surface 107 reaches one branch cart 115 </ b> A via the cart 114. The shutter at the exit of the branch cart 115A is open, and the cut pieces of the in-furnace structures that have reached the branch cart 115A are stored in the storage container 111 placed on the storage container cradle 119 immediately below the outlet of the branch cart 115A. Fall into. Since the shutters at the outlets of the branch carts 115B and 115C are closed, the cut pieces do not fall from the outlets of the branch carts 115B and 115C. The supply state of the cutting piece to the storage container 111 placed on the storage container cradle 119 is monitored by a camera 135 attached to the transport device 106.

  When a predetermined amount of cut pieces are stored in the storage container 111 immediately below the outlet of the branch cart 115A, the supply of the cut pieces to the storage container 111 is stopped. The supply stop of the cutting piece to the storage container 111 will be described with reference to FIG.

  When the cutting piece is stored in the storage container 111 placed on the storage container cradle 119, the weight of the storage container 111 increases, and the storage container cradle 119 supported by the spring 120 is set to the weight. Corresponding descent. When a predetermined amount of cutting pieces are stored in the storage container 111, the storage container pedestal 119 is lowered to the position shown in FIG. 50 by the weight of the stored cutting pieces, so that the wire attached to the storage container pedestal 119 118 is also lowered. As a result, as shown in FIG. 50, the outlet of the branch cart 115A moves upward from the position of the lower end of the cart 114, and the cutting pieces are automatically supplied from the outlet of the branch cart 115A to the storage container 111. Stopped.

  When the outlet of the branch cart 115A moves above the position of the lower end of the cart 114, the shutter of the outlet is closed and the shutter of the outlet of the branch cart 115B is opened. For this reason, the cutting piece in the cart 114 is supplied from the outlet of the branch cart 115B into the storage container 111 on the storage container receiving base 119 located directly below the outlet. When a predetermined amount of cutting pieces are supplied into the storage container 111, as described above, the outlet of the branch cart 115B is lifted by the lowering of the storage container receiving base 119, and the cutting pieces from the branch cart 115B to the storage container 111 are lifted. Is stopped, and the exit shutter of the branch cart 115B is closed. At this time, the shutter at the exit of the branch cart 115C is opened. The cutting pieces in the cart 114 are supplied from the outlet of the branch cart 115C into the storage container 111 on the storage container cradle 119 located immediately below the outlet. The supply of the cutting piece from the branch cart 115C to the storage container 111 is stopped when the outlet of the branch cart 115B is lifted up like the branch carts 115A and 115B. At that time, the shutter at the exit of the branch cart 115A is opened.

  The storage container 111 in which a predetermined amount of cutting pieces is stored just below the outlet of the branch cart 115A is suspended by the suspension device 106B of the transport device 106 and moved toward the control rod drive mechanism hatch 104, and the belt It is placed on the conveyor 112. The storage container 111 passes through the control rod drive mechanism hatch 104 by driving the belt conveyor 112 and reaches the space 101B. In the space 101 </ b> B, the storage container 111 is suspended in the suspension device 103 </ b> B of the transport apparatus 103 surrounded by the radiation shielding body and stored in the transport container 113. Each storage container 111 in which a predetermined amount of cutting pieces are stored just below the outlets of the branch carts 115B and 115C is also transferred and stored in the transport container 113 in the space 101B. The transport container 113 storing the predetermined number of storage containers 111 storing the cutting pieces is transferred into the space 101A through the carry-in / out air lock 101E, and through the access passage communicated with the space 101A. It is transferred to a predetermined area inside the radioactive waste processing building outside the furnace building 23 and stored.

  The time required for the storage container 111 on the storage container cradle 119 to be transferred to the belt conveyor 112 by the suspension device 106B and the suspension device 106B return from directly above the belt conveyor 112 to just above the storage container cradle 119. It is possible to shorten the opening / closing cycle of the shutters at the outlets of the branch carts 115A, 115B, and 115C in consideration of the total time required for the operation.

  After the cutting of the in-reactor structure in the reactor pressure vessel 3 by the cutting device 99 is started, the steps S16, S23, and S24 are substantially performed in parallel.

  A camera 134 installed on the inner surface of the pedestal 15 monitors the state of the cutting piece on the inclined surface 107. The video imaged by the camera 134 is displayed on a display device (not shown) installed outside the reactor building 23, and the operator monitors the video image displayed on the display device. When the amount of cutting pieces deposited on the inclined surface 107 increases, the amount of cutting pieces falling from the reactor pressure vessel 3 is larger than the amount of cutting pieces supplied to the storage container 111. Show. In this case, the lowering speed of the cutting device 99 is reduced by reducing the rotational speeds of the winding devices 97A and 97B installed on the support member 131. On the contrary, when the amount of the cutting piece on the inclined surface 107 decreases, the descending speed of the cutting device 99 is increased. The descending speed is monitored by an operator on the operation panel 140 installed in the operation operation room 140 shown in FIG. 58, and a cut piece of the in-furnace structure on the inclined surface 107 (when the fuel debris described later is cut, the fuel is reduced). The lowering speed of the cutting device is adjusted according to the accumulation state of the debris cutting pieces). Alternatively, a load meter 141 (see FIG. 58) is installed under the inclined surface of the shock absorber 109, and a predetermined amount of a cut piece of the in-furnace structure measured by the load meter 141 (at the time of cutting fuel debris described later) The cutting speed of the cutting device 99 is controlled by a control device (not shown) provided on the operation panel in the operation operation room 140 based on the load when the fuel debris cutting pieces are deposited on the inclined surface. Also good.

  By lowering the cutting device 99 in the reactor pressure vessel 3 while the rotating body 99B rotates, the in-furnace structure to be cut becomes the in-furnace structure close to the lower mirror part 5. The cut pieces of the in-furnace structure also fall on the inclined surface of the shock absorber 109 from the respective through holes 132 formed in the lower mirror part 5, pass through the cart 114, and enter the storage container 111 on the storage container receiving base 119. Supplied. An empty storage container 111 is placed on the storage container cradle 119 to which the storage container 111 has been transported.

  For example, the necessary number of empty storage containers 111 are transported in the reactor containment vessel 17 using the joint access device disposed in the space 101B before the through-hole 132 is formed in the lower mirror unit 5. Is placed in advance in a region around the conveying device 106 on a grating (not shown) on the horizontal beam 133 on which is installed. A multi-joint access device (not shown) that can run on the grating is carried into the reactor containment vessel 17 in advance, and a gripping tool attached to the tip of the multi-joint arm of this multi-joint access device. The empty storage container 111 placed on the grating is grasped, and the empty storage container 111 is placed on the storage container receiving base 119 on which the storage container 111 is not placed.

  When the cutting of the in-reactor structure is advanced by the cutting device 99 in the reactor pressure vessel 3, the cutting device 99 approaches the lower mirror unit 5. Eventually, the fuel debris 39A existing near the lower mirror part 5 in the reactor pressure vessel 3 starts 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 height of the mixture is high, so that it is 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 picked up from the surface using either the injection nozzle 99F or the laser head 99G provided in the picking head 99D. When the injection nozzle 99F for the water jet or the abrasive water jet is used, the water jet or the abrasive 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 abrasive water jet. . When the laser head 99G is used, a laser is irradiated from the laser head 99G onto the surface of the fuel debris 39A so as to hold the surface of the fuel debris 39A.

  In order to efficiently suspend the fuel debris 39A by the injection nozzle 99F or the laser head 99G, the suspension head 99D is moved in the direction of the rotation axis of the rotating body 99B so that the water jet, the abrasive water jet, or the laser does not hit the cutting blade 99C. It moves 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, a water jet or an abrasive water jet is injected into the fuel debris 39A or a laser is irradiated onto the fuel debris 39A. The jetting of the water jet or the abrasive water jet or the laser irradiation is performed while rotating the suspension head 99D.

  By slowly rotating the rotating body 99B while moving the suspension 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 rotated at any position in the radial direction and circumferential direction of the reactor pressure vessel 3. Can be hung. The suspended pieces (cut pieces) of the fuel debris 39A generated by this suspension fall on the inclined surface 107 of the shock absorber 109 below the reactor pressure vessel 3 through the respective through holes 132 formed in the lower mirror 5, and Similarly to the cut piece of the in-furnace structure, it is stored in the storage container 111 placed on the storage container cradle 119 outside the pedestal 15. As described above, the storage container 111 is transported to and stored in a predetermined area in the radioactive waste treatment building.

  In the present embodiment, the reactor internal structure and the fuel debris 39A cut pieces existing in the reactor pressure vessel 3 are dropped into the lower plenum 20 in the pedestal 15 through the through-holes 132 formed in the lower mirror part 5; In order to transport the fallen cut pieces out of the pedestal 15 and store them in the storage container 111 for transport, the cut pieces of the reactor internal structure and fuel debris 39A are stored in the storage container and placed above the reactor pressure vessel 3. Compared with the case of transferring to the operation floor 24, it can be transferred from the reactor pressure vessel 3 to the outside in a short time.

  In addition, each piece of the reactor internal structure and the fuel debris 39A is dropped from the reactor pressure vessel 3 onto the inclined surface 107 of the shock absorber 109 located below the reactor pressure vessel 3, so that it is positioned at the pedestal 15. The storage container 111 can be stored substantially continuously.

  In the present embodiment, a storage container cradle 119 that descends according to the weight of a cut piece in the storage container 111, a branch cart (second cart) 115A that is rotatably attached to a cart (first cart) 114, and a storage container. Since a cutting piece supply stop device having a lifting mechanism for lifting the outlet portion of the branch cart 115A as the receiving table 119 descends is provided, a predetermined amount of cutting pieces are supplied into the storage container 111 on the storage container receiving table 119. When it does, supply of the cut piece to this storage container 111 can be stopped. For this reason, a predetermined amount of cut pieces can be stored in each storage container 111 without overflowing the cut pieces.

  Other proposals for storing the internal structure of the reactor falling to the lower plenum 20 in the pedestal 15 through the through-hole 132 formed in the lower mirror portion 5 of the reactor pressure vessel 3 and the cut pieces of the fuel debris 39A in the storage vessel 111. Will be described with reference to FIG. In this scheme, the support plate 121 is disposed on the shock absorber 109 with the top surface disposed in the lower plenum 20 in the pedestal 15 being horizontal, and a large number of storage containers 111 are disposed on the support plate 121. In FIG. 51, the pressing device disposed on the right side on the inner surface of the pedestal 15 pushes a number of storage containers 111 on the support plate 121 to the left side. When one storage container 11 is taken out, a large number of storage containers 11 are pressed to the left by the pressing device, so that each storage located on the right side fills the area where the storage container 111 is disposed. The container 111 moves to the left side. A work arm 121 having a multi-joint is disposed above each storage container 111 in the pedestal 15 and attached to the inner surface of the pedestal 15. Another working arm 122 having a multi-joint is installed outside the pedestal 15 in the vicinity of the region where the transfer device 106 in the reactor containment vessel 17 is disposed. A belt conveyor 124 is installed in the pedestal opening 105. When one storage container 11 is taken out, an empty storage container 111 is added to the rightmost side of the pedestal 15 in FIG.

  Cutting pieces that fall from the through holes 132 formed in the lower mirror 5 of the reactor pressure vessel 3 are supplied into the storage vessels 111 on the support plate 121. As a result of monitoring by the camera 134, the storage container 111 in which the cutting pieces are stored up to the upper end is gripped and lifted by the work arm 121 and placed on the belt conveyor 124. The storage container 111 passes through the pedestal opening 105 and reaches the installation area of the transfer device 106 in the reactor storage container 17 outside the pedestal 15. The storage container 111 is gripped by the work arm 122 and suspended from the suspension device 106B of the transport device 106, and placed on the belt conveyor 112. As described above, the storage container 111 passes through the spaces 101B and 101A and is transported to a predetermined storage location outside the reactor building 23.

  Even in the plan shown in FIG. 51, each cut piece of the reactor internal structure and fuel debris 39 </ b> A is dropped from the reactor pressure vessel 3 to the lower plenum 20, and this fallen cut piece is stored in the storage container 111. Similarly to the method of carrying out the cut pieces shown in FIG. 47, the cut pieces of the reactor internal structure and the fuel debris 39A can be transported from the reactor pressure vessel 3 to the outside in a short time.

  A method for removing fuel debris according to embodiment 2, which is another preferred embodiment of the present invention, will be described with reference to FIG. The fuel debris retrieval method of the present embodiment is applied to a boiling water nuclear power plant, and a step S25 is added in the reactor opening operation, and step S10 in the first embodiment is replaced with step S10A. Other steps performed in the fuel debris retrieval method of the present embodiment are the same as those performed in the fuel debris retrieval method of the first embodiment.

  The fuel debris retrieval method of the present embodiment will be described focusing on steps S25 and S10A. Also in the fuel debris retrieval method of this embodiment, the steps S1 to S9 are performed. Thereafter, the first radiation shield is removed (step S25). A water shield 59 disposed between the containment head 18 and the shield plug 28 in the reactor well 25 with the radiation shield 59 disposed on the floor member 58 above each shield bag 48 filled with water. Each of the shielding bags 48 filled with is removed using the shielding body transfer device 47. Before removing the shielding bag 48, the water inside is drained out of the shielding bag 48. The slide mechanism 45B and the telescopic tube 45A of the shield transfer device 47 existing in the isolation chamber 40 carried into the radiation shield container 32 are moved toward the reactor well 25, and the work arm 45C is operated to hold the gripper 47A. Thus, the shielding bag 48 from which the water has been discharged is grasped. The gripping tool 47A is moved into the isolation chamber 40 and the shielding bag 48 is released. The remaining shielding bag 48 is also collected in the chamber 40 in the same manner. The water discharged from the shielding bag 48 in the dry well 25 is collected in the drain tank in the isolation chamber 40 by the pump and the drain hose as in step S4. The doors 64A and 64B are closed, and the isolation chamber 40 in the radiation shielding container 32 is transferred to the outside.

  Thereafter, the equipment in the reactor well is removed and carried out (step S10A). In Step 10 of the first embodiment, the cut storage container head 18 is covered with a shielding bag 48 filled with water and carried out. On the other hand, in Step 10A of the present embodiment, the radiation shielding suspension balance device 74 used for removing the heat insulating material in Embodiment 1 is used instead of the shielding bag 48 filled with water. The structure of the radiation shielding suspension balance device 74 has already been described in the removal of the heat insulating material.

  The radiation shielding suspension balance device 74 is carried into the space 53A and suspended from the overhead crane 50A (see FIG. 54). As described above, the radiation shielding suspension balance device 74 is filled with water in each of the ceiling portion 74B and the side wall portion 74C. Before the radiation shielding suspension balance device 74 is lowered, the radiation shielding body 59 installed on the floor member 58 is removed. After that, the radiation shielding suspension balance device 74 is suspended from the overhead crane 50A, lowered toward the reactor well 25 from the space 53A, and passed through the isolation sheet 54 that is opened and closed and opened in the reactor well 25. Is lowered. Further, the radiation shielding suspension balance 74 is lowered until the lower surface of the cylindrical side wall portion 74C reaches the vicinity of the baffle plate 76, and the storage container head 18 is inserted into the cylindrical side wall portion 74C (see FIG. 55). . At this time, each of the gripping tools 75C and 75D grips a pair of suspension tools provided on the top of the storage container head 18. The storage container head 18 is covered by a radiation shielding suspension balance device 74. The cutting machine 125 attached to the ring-shaped guide rail on the lower surface of the cylindrical side wall 74C cuts the side wall of the storage container head 18 near the baffle plate 76 while moving along the guide rail. When the cutting machine 125 goes around the ring-shaped guide rail, the lower end portion of the side wall of the storage container head 18 is completely cut (see FIG. 55).

  While the containment head 18 is cut, the radiation shielding suspension balance device 74 covers the containment head 18, so that the radiation emitted upward from the reactor pressure vessel 3 is filled with water. It is shielded by a radiation shielding suspension balance device 74. For this reason, the dose in the spaces 53A and 53B can be reduced.

  After cutting the storage container head 18, the cut storage container head 18 is pulled up by the overhead crane 50 </ b> A while being covered with the radiation shielding suspension balance device 74. When a predetermined space is formed between the lower end of the storage container head 18 and the top of the heat insulating material 30 because the lower end of the storage container head 18 reaches above the top of the heat insulating material 30 covering the pressure container head 4. The raising of the storage container head 18 is stopped (see FIG. 56).

  The expansion / contraction tube 71B of the decontamination apparatus 71 carried into the radiation shielding container 32 is extended toward the reactor well 25, and the work arm 71C and the injection nozzle 71D are insulated from the lower end of the containment vessel head 18 and the temperature inside the reactor well 25. Reach between the tops of the material 30. Water is sprayed from the spray nozzle 71D toward the inner surface of the storage container head 18, the inner surface of the storage container head 18 is washed by this water (see FIG. 56), and the attached radionuclides are washed away. As described above, the water dropped downward after the cleaning is collected in the drain tank in the isolation chamber 40 using the pump and the drain hose.

  After the decontamination of the storage container head 18 is completed, the spray nozzle 71D of the decontamination apparatus 71 is accommodated in the isolation chamber 40. The isolation chamber 40 is transported from the radiation shielding container 32 to the ground.

  The decontaminated storage container head 18 is moved to the space 53A by the overhead crane 50A. Then, the radiation shielding body 59 is installed on the floor member 58, and the water in the radiation shielding suspension balance device 74 is discharged. The lightened radiation shielding suspension balance 74 and the cut storage container head 18 are conveyed to the outside.

  The heat insulating material 30 covering the pressure vessel head 4 is also cut in the same manner as the storage vessel head 18 and conveyed to the outside.

  After the process of step S10A is completed, the processes of steps S11 to S13 are performed, and the method for opening the reactor pressure vessel is completed. Further, each step of Steps S17 to S20 performed in Example 1 (removal operation of fuel debris dropped on the bottom of the reactor containment vessel), and each step of Steps S14 to S16, S23 and S24 (fuel in the reactor) Debris retrieval work) is carried out.

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

  DESCRIPTION OF SYMBOLS 2 ... Reactor, 3 ... Reactor pressure vessel, 4 ... Pressure vessel head, 5 ... Lower mirror part, 6 ... Core shroud, 7 ... Core, 9 ... Core support plate, 10 ... Upper lattice plate, 11 ... Air-water separation 12 ... Steam dryer, 17 ... Reactor containment vessel, 18 ... Containment vessel head, 23 ... Reactor building, 24 ... Operation floor, 25 ... Reactor well, 26 ... Dryer separator pool, 28 ... Shield plug, 29A ... Throttle plug, 32 ... radiation shielding container, 40 ... isolation chamber, 41 ... perforation device, 46 ... decontamination device, 47 ... shielding body transport device, 48 ... shield bag, 49 ... isolation house, 54 ... isolation film, 70 ... Cutting device 74 ... Radiation shield suspension balance device 81 ... Isolation container 81A ... Upper cylindrical member 81B ... Intermediate cylindrical member 81C ... Lower cylindrical member 89, 90 ... Carry-in / out air lock, 94 ... Dismantling 95, storage container transport device, 99 ... cutting device, 99B ... rotating body, 99C ... cutting blade, 99D ... hanging head, 99F ... injection nozzle, 99G ... laser head, 100 ... biological shield, 101A, 101b, 106 DESCRIPTION OF SYMBOLS ... Conveying device, 104 ... Control rod drive mechanism hatch, 105 ... Pedestal opening, 107 ... Inclined surface, 109 ... Shock absorber, 111 ... Storage container, 114 ... Cart, 115a, 115b, 115c ... Branch cart, 121, 122 ... Working arm, 129 ... boring device, 132 ... through hole.

Claims (24)

An equipment temporary storage pool and a reactor well communicated with the equipment temporary storage pool are formed on an operation floor of a reactor building, and the reactor well is covered with a shield plug, the equipment temporary storage pool and the reactor In a method of opening a reactor pressure vessel arranged in the reactor containment vessel in a nuclear power plant in which a passage connecting the wells is sealed with a throttle plug and a reactor containment vessel is arranged in the reactor building There,
Install a radiation shielding container in the equipment temporary pool,
Forming a first through hole in the throttle plug from within the radiation shielding container;
The first radiation shielding body is transferred from the radiation shielding container into the reactor well sealed with the shield plug through the first through hole, and the containment vessel head of the reactor containment vessel is placed under the shield plug. A method of opening a reactor pressure vessel characterized by covering with the first first radiation shielding body.   The method for opening the reactor pressure vessel according to claim 1, wherein a shielding bag filled with water is used as the first radiation shielding body.   3. The cleaning of the shield plug and the containment vessel head in the reactor well is performed through the first through hole before the first radiation shield is transferred into the reactor well. 4. Opening the reactor pressure vessel.   The isolation house which covers the said reactor well is installed on the said operation floor, The said shield plug is removed in the state which covered the said containment vessel head with the said 1st 1st radiation shielding body. A method of opening the reactor pressure vessel described in 1.   5. The method of opening a reactor pressure vessel according to claim 4, wherein the containment head covered with the first radiation shield is removed from the containment vessel and the removed containment head is transferred into the isolation house. .   After removing the shield plug, a second radiation shield is disposed on the operation floor above the first radiation shield, and the containment in the reactor well is in a state where the second radiation shield is disposed. 5. The method of opening a reactor pressure vessel according to claim 4, wherein the first radiation shield covering the vessel head is removed.   The containment vessel head is covered with a radiation shield suspension balance device, the containment vessel head is suspended from the radiation shield suspension balance device, the containment vessel head is removed from the reactor containment vessel, and the removed containment vessel head is removed from the radiation containment vessel. The method for opening the reactor pressure vessel according to claim 6, wherein the reactor pressure vessel is transferred to the isolation house in a state of being covered with a shield suspension balance device.   The method for opening the reactor pressure vessel according to claim 5 or 7, wherein after removing the containment vessel head, the pressure vessel head attached to the reactor pressure vessel is removed. An equipment temporary storage pool and a reactor well communicated with the equipment temporary storage pool are formed on an operation floor of a reactor building, and the reactor well is covered with a shield plug, the equipment temporary storage pool and the reactor In a method of opening a reactor pressure vessel arranged in the reactor containment vessel in a nuclear power plant in which a passage connecting the wells is sealed with a throttle plug and a reactor containment vessel is arranged in the reactor building There,
An isolation house covering the reactor well is installed on the operation floor,
Removing the shield plug with the containment vessel head covered with a first radiation shield;
An isolation vessel covering a pressure vessel head attached to the reactor pressure vessel is disposed in the reactor well and the isolation house,
A method of opening a reactor pressure vessel, wherein the pressure vessel head removed from the reactor pressure vessel is transferred upward in the isolation vessel.   The reactor pressure according to claim 9, wherein the method for opening the reactor pressure vessel according to any one of claims 1 to 3 is implemented before removing the shield plug before placing the isolation vessel. How to open the container.   The pressure vessel head that moves upward in the isolation container is transferred into the isolation house through a first airlock attached to the isolation container at the position of the isolation house. Opening the reactor pressure vessel.   When the pressure vessel head is moved upward in the isolation vessel, the pressure vessel head to be moved upward is formed in a shielding bag filled with water disposed above the pressure vessel head. The method for opening a reactor pressure vessel according to any one of claims 9 to 11, wherein the reactor pressure vessel ascends in the formed through hole.   After the pressure vessel head is removed, the steam dryer removed from the reactor pressure vessel is taken out from the reactor pressure vessel into the isolation vessel, and the radiation shielding vessel installed in the equipment temporary storage pool The method of opening a reactor pressure vessel according to any one of claims 9 to 12, wherein the reactor pressure vessel is transferred into the radiation shielding vessel through a second airlock attached to the isolation vessel at a position of.   After the shield plug is removed and before the isolation container is placed, the containment head covered with the first radiation shield is removed from the reactor containment, and the removed containment head is isolated. The method for opening a reactor pressure vessel according to any one of claims 9 to 13, which is transferred into a house.   Before the isolation container is placed after the shield plug is removed, the second radiation shield is placed on the operation floor above the first radiation shield and the second radiation shield is placed. The method of opening a reactor pressure vessel according to any one of claims 9 to 13, wherein the first radiation shield covering the containment vessel head in the reactor well is removed. A reactor containment vessel that is installed in a reactor building and surrounded by a biological shielding body that is a part of the reactor building, and a cylindrical reactor pressure vessel support member installed in the reactor containment vessel A fuel debris retrieval method comprising a reactor pressure vessel supported and surrounded by the reactor containment vessel,
Removing the pressure vessel head attached to the reactor pressure vessel and opening the reactor pressure vessel;
Forming a second through hole in the bottom of the reactor pressure vessel;
In the reactor pressure vessel, the reactor internal structure and fuel debris in the reactor pressure vessel are cut,
Each piece of the reactor internal structure and the fuel debris is discharged to a region surrounded by the reactor pressure vessel support member below the reactor pressure vessel through the second through hole. To remove fuel debris.   The fuel debris according to claim 16, wherein the cut piece discharged through the second through hole is transferred to the reactor pressure vessel support member through a first opening formed in the reactor pressure vessel support member. Extraction method. The first opening formed in the reactor pressure vessel support member of the shock absorber disposed in the region surrounded by the reactor pressure vessel support member, the cut piece discharged through the second through hole. Fall on an inclined surface inclined toward
The fuel according to claim 16, wherein the fallen cut piece is lowered along the inclined surface and supplied to a storage container placed outside the reactor pressure vessel support member through the first opening. Debris retrieval method.   Prior to forming the second through hole in the bottom of the reactor pressure vessel, the fuel debris that has fallen from the reactor pressure vessel to the region surrounded by the reactor pressure vessel support member is removed from the reactor pressure vessel support member. The removal of fuel debris according to claim 16, wherein the fuel debris is transferred to the outside of the reactor containment vessel through the first opening formed in the body and the second opening formed in the biological shield surrounding the periphery of the reactor containment vessel. Method.   The opening of the reactor pressure vessel is performed by performing the method of opening the reactor pressure vessel according to any one of claims 1 to 8. How to retrieve fuel debris.   The opening of the reactor pressure vessel is performed by performing the method of opening the reactor pressure vessel according to any one of claims 9 to 15. How to retrieve fuel debris. The first opening formed in the reactor pressure vessel support member of the shock absorber disposed in the region surrounded by the reactor pressure vessel support member, the cut piece discharged through the second through hole. Fall on an inclined surface inclined toward
Monitor the amount of the fallen piece,
The fuel debris retrieval method according to claim 16, wherein the amount of the cut piece discharged through the second through hole is adjusted based on the amount of the cut piece deposited on the inclined surface.   The amount of the cut pieces discharged through the second through hole is adjusted by adjusting a descending speed of a cutting device that is disposed in a reactor pressure vessel and cuts the in-core structure and the fuel debris. The fuel debris retrieval method according to claim 22.   The amount of the cut piece discharged through the second through-hole is adjusted based on a load applied to the inclined surface measured by a load meter, and is arranged in a reactor pressure vessel and The fuel debris retrieval method according to claim 22, wherein the fuel debris retrieval method is performed by adjusting a descending speed of a cutting device that cuts the fuel debris.

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