JP4055156B2 - Reactor pressure vessel replacement method - Google Patents

Description

  The present invention relates to a method for replacing a reactor pressure vessel installed in a reactor building.

The nuclear power plant can extend the life of the nuclear power plant by extending the reactor pressure vessel. With regard to carrying out the reactor pressure vessel from the reactor building and carrying it into the reactor building, a method has been proposed in which an opening is provided on the roof of the reactor building and the reactor pressure vessel is carried out and carried in through this opening. (See Patent Document 1).
Also, the reactor pressure vessel placed outside the reactor building is lifted and transported in a lying state, and the reverse of the method of raising the pressure vessel above the opening of the reactor containment vessel and carrying it into the reactor containment vessel. There has been proposed a method for carrying out the reactor pressure vessel to the outside of the reactor building according to the procedure (see Patent Document 2).
JP 2003-215294 A JP-A-57-151892

However, in the former technique, since a vertically long reactor pressure vessel is carried in and out while standing, it is necessary to provide a huge gate-type support structure that straddles the reactor building. In addition, it is necessary to take measures in the building so that it does not fall to the spent fuel pool when the reactor pressure vessel is suspended. However, if the measure is taken, the overhead crane in the building will not be able to travel, and incidental work will be delayed. There is a problem.
On the other hand, in the latter technique, the procedure for lifting and loading the reactor pressure vessel in a lying state is shown, but for the specific reactor equipment configuration required to carry out the reactor pressure vessel, Not proposed. In other words, when carrying out the reactor pressure vessel, it is necessary to prevent the radioactive material from being scattered outside, so it is sufficient to simply remove the reactor pressure vessel in the reverse order of the loading method. There are problems such as being unable to secure. In particular, there is a problem that interference with the pool gate or the like must be avoided when the attitude of the reactor pressure vessel is changed in the vicinity of the reactor well.

  The present invention has been made in view of the above-described circumstances, and when replacing the reactor pressure vessel installed in the reactor building, sufficiently ensure the safety of carrying out and carrying in the reactor pressure vessel. The purpose of this is to propose a reactor pressure vessel replacement method.

The reactor pressure vessel replacement method according to the present invention employs the following means in order to solve the above problems.
Reactor pressure vessel replacement method according to the present invention The present invention includes a step of storing a steam dryer and shroud head removed from a reactor pressure vessel in a water-filled equipment pool, and the steam dryer in the equipment pool. And a step of covering the shroud head with a shielding material, a step of draining water stretched on the equipment pool, an unloading of the steam dryer and the shroud head covered with the shielding material from the equipment pool, and Moving the reactor pressure vessel to a region that does not interfere with the reactor pressure vessel, removing a pool gate that partitions the reactor well and the equipment pool, and moving the reactor pressure vessel from above the reactor well to above the equipment pool. characterized by chromatic and step of changing the posture from the standing state is moved to the side to lying state, the.
According to the present invention, it is possible to change the attitude of the reactor pressure vessel without interfering with peripheral equipment such as a pool gate without lifting the reactor pressure vessel to a position above the reactor well.
Further, when the steam dryer and shroud head removed from the reactor pressure vessel are exposed, a large amount of radiation from these devices can be shielded to prevent excessive exposure. Furthermore, it is possible to avoid interference between the reactor pressure vessel and peripheral equipment. In addition, since the reactor pressure vessel does not move to the spent fuel pool side, interference between the reactor pressure vessel and the spent fuel pool pool gate is avoided, and radiation from spent fuel due to pool water loss is avoided. Release of active substances can be prevented.

Further, in the case where the shielding member is composed of at least two members which form an internal space for accommodating the steam dryer or the shroud head by being combined, the steam dryer and the shroud are provided in the water-filled equipment pool. The head can be accommodated inside the shielding material.

According to the present invention, the following effects can be obtained.
The present invention relates to a reactor pressure vessel replacement method including a step of changing the posture of a reactor pressure vessel from a standing state to a lying state or from a lying state to a standing state in the vicinity of the reactor well. The pool gate that divides the equipment pool was removed, and the attitude of the reactor pressure vessel was changed. For this reason, it becomes possible to change the attitude of the reactor pressure vessel without interfering with peripheral equipment such as a pool gate. Therefore, there is no need to take measures in the building that do not fall to the spent fuel pool side when suspended, so that the extension of construction period and costs due to the measures can be suppressed.
In addition, a large amount of radiation from the steam dryer and shroud head can be shielded, and the release of radioactive materials from the spent fuel due to the loss of spent fuel pool water can be prevented. Radiation exposure can be avoided.

Hereinafter, an embodiment of a reactor pressure vessel replacement method of the present invention will be described with reference to the drawings.
FIG. 1 is a longitudinal sectional view showing a configuration of a nuclear reactor facility 1 which is a part of a boiling water nuclear power plant (BWR plant). FIG. 2 is a longitudinal sectional view showing a detailed configuration of the reactor pressure vessel 4.
The nuclear reactor facility 1 includes a nuclear reactor building 2, an attached building 20, and a crossing passage 30 that connects the nuclear reactor building 2 and the attached building 20.

The reactor building 2 is erected on the ground and includes a reactor containment vessel 3 (Primary Containment Vessel) inside.
The reactor containment vessel 3 is a building important for safety of the reactor, and houses the reactor pressure vessel 4 and structures such as cooling system equipment. Generally, it is made of light bulb-shaped or bell-shaped steel or reinforced concrete, and has an airtight and pressure-resistant structure, and radioactive materials are released to the outside in the event of an accident such as a reactor accident or damage to the reactor cooling system. It serves to prevent. In addition, in this embodiment, it forms in a bell shape.
The reactor pressure vessel 4 (reactor pressure vessel) is a vertical cylindrical shape with a hemispherical top and bottom, and includes a reactor pressure vessel upper lid (RPV upper lid 53) and a reactor vessel shell 4b. The reactor pressure vessel 4 is installed on the pedestal 9 and is fixed by a foundation bolt and is self-supporting. Note that the pedestal 9 is a structure of concrete and a steel plate frame or a reinforcing bar because it serves as the foundation of the reactor pressure vessel 4.
A reactor shielding wall 5 for shielding radiation from the reactor is provided outside the reactor pressure vessel 4. The reactor shielding wall 5 is an iron plate frame concrete structure having a thickness of 600 to 700 mm.
The RPV upper lid 53, which is the upper lid of the reactor pressure vessel 4, is fixed to the flange 4c of the reactor pressure vessel body 4b by bolts. In addition, a nozzle such as a main steam outlet nozzle 80 is attached to the reactor pressure vessel 4 and is connected to piping outside the reactor pressure vessel 4.

  At the top of the reactor containment vessel 3, when the structure in the fuel assembly 10 or the reactor pressure vessel 4 is exchanged or taken out, the reactor well 6 is filled with shielding water that shields radiation from the fuel assembly 10 or the like. Is provided. When exchanging the reactor pressure vessel 4, the reactor pressure vessel 4 is unloaded from the reactor well 6 and loaded.

FIG. 3 is a plan layout view of the operation floor 11 of the reactor building 2.
The operation floor 11 in the reactor building 2 includes a spent fuel pool 7 for storing the spent fuel assembly 10 and an equipment pool 8 for storing the reactor internal structure taken out from the reactor. Are arranged symmetrically with respect to the reactor well 6. The spent fuel pool 7 is filled with water to shield radiation from the spent fuel assembly.

A traveling rail 12 is laid on the operation floor 11 so as to straddle the reactor well 6, the spent fuel pool 7, and the equipment pool 8. A portal crane 13 that suspends and conveys the reactor pressure vessel 4 is placed on the traveling rail 12.
A first opening 41 through which the portal crane 13 can pass is provided on the side wall 2a on the equipment pool 8 side of the reactor building 2, and a first hermetic door 42 is further provided in the first opening 41. . Thereby, it is prevented that a radioactive substance is discharged | emitted from the reactor building 2 outside at the time other than passage of the portal crane 13. FIG.

Returning to FIG. 1, the attached building 20 is connected to the reactor building 2 through the transfer passage 30. The attached building 20 is a facility used to carry out and carry in the reactor pressure vessel 4, and is erected at substantially the same height as the reactor building 2, and its inside is hollow.
The traveling rails 12 are also laid in the attached building 20 and the crossing passage 30. Therefore, the portal crane 13 can reciprocate through the passage 30 between the reactor building 2 and the attached building 20.
In addition, a second opening 43 through which a heavy goods transporting vehicle 22 (see FIG. 10) loaded with the reactor pressure vessel 4 can pass is provided on the ground floor 21 of the annex building 20, and this second opening is further provided. A second hermetic door 44 is provided at 43. The second hermetic door 44 is interlocked so as not to be opened simultaneously with the first hermetic door 42. Thereby, when the reactor pressure vessel 4 is carried out, the inside of the reactor building 2 can be maintained at a negative pressure, and the radioactive substance is prevented from being released to the outside.

In the space between the reactor building 2 and the accessory building 20, in other words, in the space between the reactor building 2 and the accessory building 20, the reactor well 6 A device storage area 60 is provided for storing the device 50 to be removed from the inside or the reactor pressure vessel 4, for example, the PCV top head 51, the RPV upper lid heat insulating material 52, the RPV upper lid 53, and the like (see FIG. 4). Normally, these devices 50 are temporarily placed on the operation floor 11 of the reactor building 2, but there are not a few cases where these devices 50 get in the way when the reactor pressure vessel 4 is carried out. For this reason, the safety | security of carrying out work may be impaired. Therefore, by storing these devices 50 in the device storage area 60, the safety of the unloading work is ensured.
The device storage area 60 includes a plurality of levels 61. The floor surface 62 of each floor 61 is configured to be openable and closable. That is, by closing the floor surface 62 of each level 61, a plurality of devices 50 removed from the reactor well 6 or the reactor pressure vessel 4 can be accommodated so as to be stacked.

Next, replacement work of the reactor pressure vessel 4 will be described with reference to FIGS.
This step is a step of carrying out and carrying in the reactor pressure vessel 4 and a part of the reactor shielding wall 5 as one body.
Specifically, disassembly process, unloading preparation process, reactor pressure vessel unloading process, reactor shield wall inner surface cleaning process, new reactor pressure vessel loading process, reactor pressure vessel peripheral recovery process, fuel reloading process, It consists of an entry process.

First, in the disconnection process, the reactor well cover 14 is removed, and then the PCV top head 51, the RPV upper lid heat insulating material 52, the RPV upper lid 53, etc. are removed from the reactor well 6.
As shown in FIG. 4, these devices are accommodated from the lower floor of the device accommodating region 60 in the order of removal from the reactor well 6 or the reactor pressure vessel 4. Specifically, the floor surface 62 other than the lowest floor in the device accommodation area 60 is opened, and the PCV top head 51 is accommodated in the lowest hierarchy 61. Next, the floor surface 62 immediately above the lowest floor 61 is closed to accommodate the RPV upper lid heat insulating material 52. Similarly, the RPV upper lid 53 and the like are accommodated so as to be stacked on the uppermost layer 61.
Subsequently, the reactor well 6 and the equipment pool 8 are filled with water, and the in-furnace structures such as the steam dryer 81 and the shroud head 83 (see FIG. 2) are removed from the furnace and transferred to the equipment pool 8. Note that an L-shaped member 91 is placed in the equipment pool 8 in advance, and a steam dryer 81, a shroud head 83, and the like are placed on the L-shaped member 91 (see FIG. 5).
Then, the pool gate 15 of the spent fuel pool 7 is opened, and the fuel assembly 10 is taken out from the furnace and transferred to the spent fuel pool 7.

In the carry-out preparation step, first, all the in-furnace structures such as the control rod guide tube 86 and the control rod drive mechanism 87 (see FIG. 2) are removed.
Next, as shown in FIG. 5, the steam dryer 81 and the shroud head 83 placed in the equipment pool 8 are covered with a shielding material 90 made of an iron plate or the like.
The shielding member 90 forms a shielded internal space 90a by combining the L-shaped member 91 and the inverted L-shaped member 92, and the steam dryer 81 or the shroud head 83 or the like is accommodated in the internal space 90a. The release of radioactive substances from the steam dryer 81 and the shroud head 83 is prevented.
Specifically, an inverted L-shaped member 92 is mounted on an L-shaped member 91 on which the steam dryer 81, the shroud head 83, etc. are placed, and is fixed by a fastening member such as a screw. Thereby, the steam dryer 81, the shroud head 83, and the like are accommodated in an internal space 90a formed by the L-shaped member 91 and the inverted L-shaped member 92. Note that a radiation seal (not shown) is provided at the joint between the L-shaped member 91 and the inverted L-shaped member 92. The shielding member 90 is provided with a drain 90c for draining water.
Next, it is confirmed that the water level of the reactor well 6 is lower than the flange 4c of the reactor pressure vessel 4, the water is drained from the equipment pool 8, and the pool gate 16 is removed. The removed pool gate 16 is placed at a predetermined location in the equipment pool 8. Here, although not essential, since it is effective in reducing the exposure of workers, it is desirable to carry out chemical decontamination on the reactor pressure vessel 4 and the connecting piping.
Thereby, there is no obstacle between the reactor well 6 and the equipment pool 8, and it is easy to change the posture above the reactor well 6 when the reactor pressure vessel 4 is carried out and carried in (FIG. 8). If there is still a possibility that the shroud head 83 or the like housed in the shielding material 90 interferes with the reactor pressure vessel 4 whose posture is being changed, the transition passage is further accommodated in the state in which these devices are housed in the shielding material 90. It is preferable to transport to the equipment storage area 60 under the floor 30 or the operation floor 11. Even when there is no possibility of interference, it is preferable to transport the equipment pool 8 to the equipment storage area 60 or the operation floor 11 in consideration of using the equipment pool 8 for incidental work.
Next, before draining the reactor pressure vessel 4, an internal shield (not shown) is attached to the top of the core shroud 84.
Then, the piping connected to the reactor pressure vessel 4 and the supporting structure thereof are removed in a necessary minimum range.
A shielding lid 70 is attached to the flange 4 c of the reactor pressure vessel 4. Since the reactor pressure vessel 4 and the reactor containment vessel 3 are connected via the bulkhead 76 and the like, the part that interferes when the reactor pressure vessel 4 is carried out is removed from the bulkhead 76 and the like.
Next, the stabilizer 77 (see FIG. 2) is removed, and the reactor pressure vessel 4 is separated from the reactor shielding wall 5. The stabilizer bracket 4d (see FIG. 2) of the reactor pressure vessel 4 and the reactor shielding wall 5 are fixed using a predetermined fixture. The reactor pressure vessel 4 is fixed so as to support the reactor shielding wall 5 in an upright state. Further, it is fixed so that the reactor shielding wall 5 can support the reactor pressure vessel 4 in the upright state, and further, the reactor pressure vessel 4 can support the reactor shielding wall 5 in the lying state.
Further, the opening of the reactor shielding wall 5 is also closed with an iron plate. The fixed part edge of the metal heat insulating material (not shown) attached to the lower inner wall of the reactor shielding wall 5 is cut. Also, the metal heat insulating material is cut off at the upper part and the lower part. Subsequently, the reactor shielding wall 5 is cut and separated into an upper part and a lower part.

Next, in the reactor pressure vessel unloading process, first, the portal crane 13 is moved from the attached building 20 to the upper portion of the reactor well 6.
Then, after cutting the pipes connected to the four main steam outlet nozzles 80 of the reactor pressure vessel 4, the suspension pins 71 are fitted into each of the main steam outlet nozzles 80 and fixed by welding. The suspension pin 71 is attached in a direction substantially perpendicular to the traveling direction of the portal crane 13. If the orientation of the main steam outlet nozzle 80 is not appropriate, a hole may be provided in the reactor pressure vessel body 4b and the suspension pin 71 may be attached. Moreover, the method of attaching two suspension metal fittings in the opposite direction perpendicular | vertical to the running direction of the portal crane 13 using the implantation bolt hole of the flange 4c may be sufficient.
When the four suspension pins 71 are located at substantially the same height, when the reactor pressure vessel 4 is placed in a horizontal (horizontal) state, the wire 73 that is hung on the lower suspension pin 71 is suspended on the upper side. It will interfere with the pin 71. Therefore, the protruding length of the hanging pin 71 on the lower side is made longer than that of the hanging pin 71 on the upper side.
Then, the wire 73 is hung on the four suspension pins 71 to separate the reactor pressure vessel 4 from the pedestal 9.

The reactor pressure vessel 4 and a part (upper part) of the reactor shielding wall 5 are lifted together. When the lower end of the reactor shielding wall 5 is pulled up above the bulkhead 76, the lifting operation is temporarily stopped.
Then, as shown in FIG. 6, the cradle 18 is placed on the dry well flange 75 of the reactor containment vessel 3, and the reactor pressure vessel 4 is temporarily placed on the cradle 18.
Next, the suspension pins 72 are attached to the two existing nozzles (recirculation inlet nozzle 85 is optimal) located below the center of gravity of the entire reactor pressure vessel 4 to be carried out and on the spent fuel pool 7 side. The attachment method of the suspension pin 72 is the same as that of the suspension pin 71. Further, the suspension pin 72 is also attached in a direction substantially perpendicular to the traveling direction of the portal crane 13. When the direction of the nozzle is not appropriate, a hole is made in the reactor pressure vessel body 4b and the suspension pin 72 is attached.
And the suspension position of the wire 73 of the portal crane 13 is changed. Specifically, the wire 73 is removed from the two suspension pins 71 on the spent fuel pool 7 side among the four suspension pins 71, and the wires 73 are hung on the two suspension pins 72 (see FIG. 7).
Then, as shown in FIG. 8, the lifting of the reactor pressure vessel 4 is resumed, and the reactor pressure vessel 4 becomes an interference (opening of the bulkhead 76, the wall surface of the reactor well 6 on the spent fuel pool 7 side, The reactor pressure vessel 4 is gradually tilted toward the equipment pool 8 side while moving the portal crane 13 so as not to interfere with the portal crane 13 main body, the ceiling truss of the reactor building 2, and the like. Since the pool gate 16 of the equipment pool 8 is removed, the reactor pressure vessel 4 can be easily tilted. Furthermore, since the steam dryer 81, the shroud head 83, and the like placed in the equipment pool 8 are accommodated in the shielding material 90 and moved to the equipment accommodating area 60 in advance, they interfere with the reactor pressure vessel 4. There is no. Thereby, the attitude | position change of the reactor pressure vessel 4 can be performed safely and reliably.
Then, when the reactor pressure vessel 4 becomes substantially horizontal (horizontal) with respect to the operation floor 11, the reactor is covered with an unloading sheet or the like, and after measuring surface contamination and surface dose rate, the portal crane 13 is attached to the attached building 20. (See FIG. 9).
Next, the first airtight door 42 of the first opening 41 is opened, and the portal crane 13 is passed through and moved to the crossing passage 30. The first hermetic door 42 is closed immediately after passing through the portal crane 13 to prevent the radioactive material from diffusing out of the reactor building 2.
Then, after the reactor pressure vessel 4 is moved to the annex building 20, the wire is extended again, and the reactor pressure vessel 4 is hung down to the ground floor 21 while lying down (see FIG. 10). At this time, on the ground floor 21 of the annex building 20, the heavy material transporting vehicle 22 is put on standby and the suspended reactor pressure vessel 4 is mounted.
Then, the wires are removed from the suspension pins 71, 72, and the heavy goods transporting vehicle 22 loaded with the reactor pressure vessel 4 is moved out of the attached building 20 from the second opening 43.

  In the reactor shielding wall inner surface care process, a metal heat insulating support (not shown) is removed for the inner surface maintenance of the reactor shielding wall 5 remaining after the reactor pressure vessel 4 is carried out. Subsequently, the inner surface of the reactor shielding wall 5 is painted.

In the new reactor pressure vessel carrying-in process, first, the new reactor pressure vessel 4 and the reactor shielding wall 5 (only the whole or only the upper part) are brought into the attached building 20 by the heavy material transporting vehicle 22.
Then, the portal crane 13 lifts four points of the reactor pressure vessel 4 and the reactor shielding wall 5 in a horizontal (horizontal) state, and carries them into the operation floor 11. The reactor pressure vessel 4 may be the main body alone, but it is preferable to carry in the reactor after installing the reactor internals such as the jet pump 88, the core shroud 84, and the control rod drive mechanism housing 89 at the factory.
The existing nozzles (the main steam outlet nozzle 80 and the recirculation inlet nozzle 85) may be used for the four-point suspension position, as in the case of carrying out. In addition, a dedicated suspension pin may be attached near an existing nozzle in advance at the factory.
Subsequently, the reactor pressure vessel 4 and the reactor shielding wall 5 are erected above the reactor well 6 and suspended in the reactor containment vessel 3.
Then, when the lower end of the reactor shielding wall 5 moves to above the bulkhead 76, the suspension operation is temporarily stopped. Then, the cradle 18 is placed on the dry well flange 75 of the reactor containment vessel 3. Then, the reactor pressure vessel 4 is temporarily placed on the cradle 18.
Next, the two wires below the center of gravity of the reactor pressure vessel 4 are removed, and the wire 73 is re-wired to the dedicated suspension pin attached at or near the main steam outlet nozzle 80. Two suspension fittings may be attached using the stud bolt holes of the flange 4c of the reactor pressure vessel 4 and used.
When the wiring is completed, the reactor pressure vessel 4 and the reactor shielding wall 5 are slightly lifted, the cradle 18 placed on the dry well flange 75 is removed, and the reactor pressure vessel 4 is suspended to the pedestal 9.
Then, the reactor pressure vessel 4 is installed at a predetermined position and fixed with a foundation bolt. In addition, the reactor shielding wall 5 is installed and fixed. Further, the jig material that has fixed the reactor pressure vessel 4 and the reactor shielding wall 5 is removed.

In the reactor pressure vessel periphery restoration process, a metal heat insulating material (not shown) and a stabilizer 77 are attached between the reactor pressure vessel 4 and the reactor shielding wall 5. Further, the bulkhead 76 that connects the reactor pressure vessel 4 and the reactor containment vessel 3 is restored. Furthermore, piping is connected to the existing nozzle of the reactor pressure vessel 4 to restore the piping structure.
Moreover, the pool gate 16 of the equipment pool 8 is attached, and the equipment pool 8 is filled with water. Then, the steam dryer 81, the shroud head 83, and the like are returned from the device storage area 60 to the device pool 8. Then, the steam dryer 81 and the shroud head 83 are removed from the shielding material 90. Specifically, the inverted L-shaped member 92 is removed from the shielding material 90.
Subsequently, in-furnace structures such as the control rod guide tube 86 and the control rod drive mechanism 87 are attached. Coordination adjustment with the reactor pressure vessel 4 of the shroud head 83 and the steam dryer 81 is also performed.
The RPV upper lid 53 is attached and the pressure resistance test is performed to confirm the soundness of the reactor pressure boundary before use. Also, the RPV upper lid 53 is removed to prepare for fuel loading.

In the fuel reloading process, the reactor well 6 is filled with water, the pool gate 15 of the spent fuel pool 7 is opened, and the fuel assembly 10 is loaded into the reactor pressure vessel 4.
Subsequently, the pool gate 16 of the equipment pool 8 is removed, and the in-furnace structures such as the shroud head 83 and the steam dryer 81 are restored.
After the reactor is restored, the RPV upper lid 53 is attached and the reactor pressure boundary leakage test is performed. Subsequently, the RPV upper lid heat insulating material 53 and the PCV top head 51 are mounted and the opening of the reactor containment vessel 3 such as the equipment hatch is closed, and then the whole leakage rate test of the reactor containment vessel boundary is performed.
Then, the reactor well cover 14 is attached, and the restoration work of the operation floor 11 is completed.

In the merging process, various tests and system configuration of the reactor building 2 necessary for restarting the startup are performed, the startup is started, the power generation is restarted, and the startup is performed.
When disassembling the attached building 20 or the crossing passage 30, the portal crane 13 is suspended, and it is carried out after confirming that there is no contamination. In addition, the attached building 20 and the like are decontaminated and disassembled. The first opening 41 is sealed.
Through the above steps, the replacement operation of the reactor pressure vessel 4 is completed.

  As described above, according to the present invention, when changing the posture of the reactor pressure vessel 4 from the standing state to the recumbent state or from the recumbent state to the standing state in the vicinity of the reactor well 6, The pool gate 16 that divides the well 6 and the equipment pool 8 was removed, and the attitude of the reactor pressure vessel 4 was changed. For this reason, it becomes possible to change the attitude of the reactor pressure vessel 4 without interfering with peripheral equipment such as the pool gate 16 without lifting the reactor pressure vessel 4 above the reactor well 6. Work safety can be ensured.

  It should be noted that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the present invention.

Longitudinal sectional view showing the configuration of nuclear reactor facility 1 Longitudinal sectional view showing the detailed structure of the reactor pressure vessel 4 Plan view of the operation floor 11 of the reactor building 2 The figure explaining the exchange work of the reactor pressure vessel 4 Replacement work diagram following FIG. Replacement work diagram following FIG. Replacement work diagram following FIG. Replacement work diagram following FIG. Replacement work diagram following FIG. Replacement work diagram following FIG.

Explanation of symbols

4 Reactor pressure vessel 6 Reactor well 8 Equipment pool 11 Operating floor (area)
16 Pool gate 60 Equipment storage area (area)
81 steam dryer 83 shroud head 90 shielding material 90a internal space 91 L-shaped member (member)
92 Inverted L-shaped member

Claims (2)

Storing the steam dryer and shroud head removed from the reactor pressure vessel in an equipment pool filled with water;
Covering the steam dryer and the shroud head with a shielding material in the equipment pool;
Draining water from the equipment pool;
Unloading the steam dryer and shroud head covered with the shielding material from the equipment pool and moving them to a region that does not interfere with the reactor pressure vessel;
Removing a pool gate that divides the reactor well and the equipment pool;
Moving the reactor pressure vessel from above the reactor well to above the equipment pool to change the posture from a standing state to a lying state;
A reactor pressure vessel replacement method characterized by comprising: 2. The reactor pressure vessel replacement method according to claim 1 , wherein the shielding material is composed of at least two members that form an internal space for housing the steam dryer or the shroud head by being combined. .

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