JP2000162388A - Replacement method for reactor pressure vessel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a replacement method for a reactor pressure vessel capable of sufficiently ensuring the strength of reactor shield walls, shortening the construction period and reducing cost. SOLUTION: In a replacement method by cutting in the circumference direction, the existing reactor shield wall at a specific elevation and replacing the cut reactor shield wall and the reactor pressure vessel, the reactor shield wall and the reactor pressure vessel are carried out in one body, a connection lid is attached on the reactor shield wall, the column, the inner steel plate and the outer steel plate of the reactor shield wall and the connection lid are welded, and mortar is filled between the reactor shield wall and the connection lid. Then a new reactor shield wall and a new reactor pressure vessel are carried in, the column at the lower end of the new reactor shield wall and the connection lid are welded, the outer steel plate of the new reactor shield wall is attached, the new inner steel plate and the new outer steel plate and the connection lid are welded and mortar is filled in the lower part of the new reactor shield wall.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for replacing a reactor pressure vessel, and more particularly to a method for carrying out a reactor pressure vessel and a reactor shield wall from a reactor building, and a new reactor pressure vessel and a reactor shield. The present invention relates to a method for replacing a reactor shield wall when a wall is carried in and installed.

[0002]

2. Description of the Related Art Nuclear power plants are designed with their service lives determined in advance, and are discarded (decommissioned) in principle after their service lives. When a nuclear power plant reaches the end of its useful life, it must be dismantled and decommissioned, so in order to supplement the power generation capacity of the decommissioned nuclear power plant and meet the ever-increasing power demand ,
A new nuclear power plant needs to be built.

[0003] However, to construct a new nuclear power plant,
It takes a long construction time and enormous costs. In addition, it is necessary to clear various issues such as selection of location candidates satisfying the conditions and obtaining consent of nearby residents. Therefore, extending the useful life of the currently operating nuclear power plants has become an important issue.

[0004] Actual nuclear power plants are designed and constructed with a sufficient margin for a determined service life, so that life can be extended by replacing only equipment and parts whose life has expired. . The reactor pressure vessel (RPV) is the most important equipment of a nuclear power plant, and the service life of the nuclear power plant generally depends on the design life of the reactor pressure vessel and the equipment in the reactor. At nuclear power plants, repair of equipment and equipment,
Replacements are made in a timely manner, and countermeasures are taken against aging.

[0005] However, deterioration over time within the service life also occurs,
For example, there is a case where an important core shroud is replaced in the furnace internals. Thus, even in-furnace equipment for which replacement measures have not been taken so far, there is a possibility that the equipment may deteriorate over time within its useful life.

[0006] For these reasons, it has become necessary to provide a method for collectively replacing the reactor pressure vessel and the reactor internals. At that time, there are issues such as shielding of highly activated facilities and equipment, shortening of plant downtime, and cost reduction.

[0007] The method of replacing the reactor pressure vessel is disclosed in Japanese Patent Application Laid-Open Nos. 8-62368 and 8-62.
No. 369 discloses that a large-scale hoist is used to install a reactor internal structure and a control rod drive mechanism housing (CRD) in a reactor pressure vessel.
Reactor shielding wall (RSW) with housing) attached
2 shows a method of unloading and loading the reactor pressure vessel. Similarly, Japanese Unexamined Patent Publication No. 9-145882 discloses that a large lifting machine is used to remove and shield a reactor shield wall and to carry out and carry in a reactor pressure vessel with a reactor internal structure and a control rod drive mechanism housing attached. Shows how to do it.

[0008] Japanese Patent Application Laid-Open No. 10-39077 discloses that
A method is shown in which the reactor shield wall is cut into an upper part and a lower part, and the reactor pressure vessel and the upper part of the reactor shield wall are simultaneously taken out and carried in. The cutting position in this example is the lower side position of the lower nozzle opening. The upper part of the new reactor shield wall to be carried in is formed up to the upper side of the lower nozzle opening, and a temporary receiving material is provided on the lower part of the reactor shield wall left in the reactor containment vessel (PCV), and the new After placing the upper part of the reactor shield wall and aligning it, a connection wall connecting the upper part of the reactor shield wall and the lower part of the reactor shield wall is installed on site, and a new reactor shield wall is being constructed.

Further, Japanese Patent Application Laid-Open No. 8-285991 discloses that an existing reactor pressure vessel is carried out, a reactor shielding wall is divided into an upper part and a lower part, and the existing reactor shielding wall upper part is carried out and cut in advance. The upper part of the new reactor shield wall, which is divided into multiple parts so that the surface is vertical and radially oriented, is carried into the reactor containment vessel, and a position that does not become an obstacle to loading the new reactor pressure vessel inside the reactor containment vessel A plurality of new reactor shield walls are temporarily placed on the new reactor pressure vessel, and a new reactor pressure vessel is loaded and installed. Discloses a method of welding a plurality of new reactor shield upper portions to each other and welding these reactor shield upper portions and lower shield walls.

[0010]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
The method of replacing the reactor shield wall disclosed in Japanese Patent No. 077 has the following problems. 1. There is no description of the connection between the old and new parts of the column, which is the strength member of the reactor shield wall. 2. It is unknown how much the manufacturing and installation errors when the old and new reactor shield walls are overlaid can be absorbed. 3. Assembling the opening of the lower nozzle is a so-called on-site matching operation, which is a complicated operation.

The method for replacing a reactor shield wall disclosed in Japanese Patent Application Laid-Open No. 8-285991 has the following problems. 1. First, the existing reactor pressure vessel is taken out alone, so it is necessary to take additional radiation shielding measures. 2. The new upper part of the reactor shield wall, which is divided into multiple parts, is carried into the reactor containment vessel, and a plurality of new reactor shield upper parts are placed inside the reactor containment vessel at a position where there is no obstacle to loading a new reactor pressure vessel. However, it is difficult to secure a temporary storage space in the containment vessel. 3. After the reactor pressure vessel is carried in, the upper part of the reactor shield wall and the lower part of the shield wall divided into a plurality of pieces are aligned with each other, and it is difficult to obtain necessary installation accuracy. 4. After the reactor pressure vessel is carried in, the upper part of the new reactor shield wall divided into multiple pieces is welded together, and the upper part of the reactor shield wall and the lower part of the shield wall are welded. The volume is enormous and the working efficiency is extremely poor.

An object of the present invention is to provide a method of replacing a reactor pressure vessel, which can shorten the construction period and reduce the cost while sufficiently securing the strength of the reactor shield wall.

[0013]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention relates to a reactor shield wall and a reactor pressure vessel which are obtained by cutting an existing reactor shield wall in a circumferential direction at a predetermined height and cutting the reactor shield wall. In the method of replacing the reactor pressure vessel, the reactor pressure vessel and the reactor shield wall are unified and carried out, and the connection lid for connecting the columns of the reactor shield wall on the reactor shield wall left as a base. The column, inner steel plate and outer steel plate of the reactor shield wall left as the base were welded to the connection lid, and mortar was filled between the reactor shield wall left as the base and the connection lid, The reactor shield wall and the new reactor pressure vessel are carried in, the column at the lower end of the new reactor shield wall and the connection lid are welded, and the inner steel plate and outer steel plate of the new reactor shield wall and the connection lid are welded. Mortar at the bottom of the new reactor shield wall We propose a method replacement of the reactor pressure vessel to be filled.

In this case, since the reactor pressure vessel and the reactor shield wall are carried out as a unit, it is not necessary to take a separate radiation shielding measure. Also, since a new cylindrical reactor shield wall is carried in, there is no need for a temporary storage space.
Furthermore, it is easy to align the cylindrical new reactor shield wall with the reactor shield wall left as the base, and the columns of the new and old reactor shield walls can be accurately adjusted while securing the column strength of the old and new reactor shield walls. Will be able to connect to

The present invention also provides a method for replacing a reactor pressure vessel, which comprises cutting an existing reactor shield wall in a circumferential direction at a predetermined height and replacing the cut reactor shield wall with a reactor pressure vessel. The reactor pressure vessel and the reactor shield wall are unified and carried out, and a connection lid for connecting the columns of the reactor shield wall is attached on the reactor shield wall left as a base, and the reactor shield wall left as a base Weld the column, inner steel plate and outer steel plate with the connection lid, fill the mortar between the reactor shield wall and the connection lid left as the base, and then replace the new reactor shield wall with the new reactor pressure vessel. Before welding, the column at the lower end of the new reactor shield wall and the connection lid are welded, the inner steel plate and the outer steel plate of the new reactor shield wall are welded to the connection lid, and the lower part of the new reactor shield wall is welded. Removal of reactor pressure vessel to fill mortar We propose a method example.

In this case, the new reactor shield wall is carried in before the new reactor pressure vessel, the column at the lower end of the new reactor shield wall and the connection lid are welded, and the outside of the new reactor shield wall is welded. Since the steel plates can be attached and the new inner steel plate and the new outer steel plate can be welded to the connection lid, in addition to the advantages of the above solution, a wider working space can be obtained and work in the reactor containment can be facilitated.

The predetermined height for cutting the existing reactor shield wall is lower than the lower nozzle opening of the reactor pressure vessel and higher than the radial beam in the existing reactor shield wall. However, it is desirable from the viewpoint of reducing the total amount of construction work.

By prefabricating the new reactor shield wall up to the lower nozzle opening as an integrated structure at the factory or on site, the amount of work in the reactor containment vessel in which various pipes, supports, etc. are complicated is greatly increased. Can be reduced.

In any case, the inside diameter of the ring formed by the connection lid is smaller than the inside diameter of the ring formed by the column of the reactor shield wall, and the outside diameter of the ring formed by the connection lid is When the diameter is larger than the outer diameter of the ring formed by the column of the shielding wall, the column can be easily aligned.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, referring to FIGS.
An embodiment of the reactor pressure vessel replacement method according to the present invention will be described.

FIG. 1 is a flow chart showing an embodiment of a procedure for carrying out / in a reactor pressure vessel and a reactor shield wall in the method for replacing a reactor pressure vessel according to the present invention. Step A: Extract existing fuel and the like. Step B: Disconnect piping connected to the existing reactor pressure vessel. Step C: Cut the existing reactor shield wall. Step D: Unload the existing reactor pressure vessel and the existing reactor shield wall. Step E: Remove the upper surface of the reactor shield wall left as a base. Step F: Attach the connection lid on the reactor shield wall left as the base. Step G: Weld the column, inner steel plate, outer steel plate, and connection lid of the reactor shield wall left as the base. Step H: Fill mortar between the reactor shield wall left as the base and the connection lid. Step I: Carry in the new reactor shield wall and the reactor pressure vessel. Step J: The column of the new reactor shield wall and the connection lid are welded. Step K: Weld the inner steel plate and the outer steel plate of the new reactor shield wall and the connection lid. Step L: Fill the lower part of the new reactor shield wall with mortar. Step M: Weld the piping connected to the new reactor pressure vessel. Step N: Attach fuel and the like.

FIG. 2 is a longitudinal sectional view showing an example of the arrangement of the reactor pressure vessel and the reactor shield wall to be carried in / out of the reactor inside the reactor building. In step A, existing fuel and the like are extracted. The removal operation of the fuel and the like in step A is a critical operation necessary for extracting all the fuel from the core, which is the same as the operation performed in the regular periodic inspection. The operation of removing fuel and the like in step A mainly includes an operation of removing the reactor containment vessel lid, that is, the reactor containment vessel head 4, an operation of removing the reactor pressure vessel cover, that is, the reactor pressure vessel head 5, and a steam dryer. That is, the operation of removing the dryer 6 and the steam-water separator, that is, the separator 7
And the operation of removing all of the fuel loaded in the core from the core and moving it to the spent fuel rack 9 of the spent fuel pool 8.

When the reactor pressure vessel head 5, the dryer 6, and the separator 7 are reused, the reactor pressure vessel head 5, the dryer 6, and the separator 7 are all removed together with the reactor pressure vessel head 5, the separator 6, and the reactor pressure vessel 2. In the case of replacement, it is attached to the reactor pressure vessel 2 again.

If there is a control rod (CR), a CR guide tube, a support bracket, a neutron flux measurement guide tube (ICM), a control rod drive mechanism (CRD), etc. that are to be reused in the furnace, at this stage It may be removed from the reactor pressure vessel, or may be carried out in parallel with Step B (cutting the existing reactor pressure vessel connection pipe) and Step C (cutting the existing reactor shield wall) described later. You may.

FIG. 3 is a longitudinal sectional view showing the positional relationship between the reactor shield vessel and the reactor pressure vessel, the nozzle and the connection pipe in the reactor containment vessel. The reactor pressure vessel 2 is provided with a main steam nozzle 11, a water supply nozzle 12, a core spray nozzle 13, a recirculated water inlet nozzle 14, a recirculated water outlet nozzle 15, various instrumentation nozzles, and a drain / vent nozzle. The main steam pipe 16, the water supply pipe 17, the core spray pipe 18, the recirculated water inlet pipe 19, the recirculated water outlet pipe 20, various instrumentation pipes, and drain / vent pipes are connected.

In step B, the various pipes connected to the existing reactor pressure vessel are cut. At this time, the bulkhead plate 21 separating the reactor well and the inside of the reactor containment vessel 10 is cut and removed, and the reactor containment stabilizer 22 of the seismic support connecting the reactor containment vessel 10 and the reactor shield wall 2 is connected. And the fuel exchange bellows 23 are cut and removed, and a carry-out port to the upper part in the reactor containment vessel 10 is secured.

Further, the base bolt 24 of the reactor pressure vessel 2
The removal operation may be performed after the cutting operation of the reactor shield wall in the next step C.

FIG. 4 is a perspective view showing the entire structure of the reactor shield wall, FIG. 5 is a developed view showing the reactor shield wall of FIG. 4 cut out in the vertical direction, and FIG. FIG. 5 is a plan sectional view taken along line AA of FIG. 5. The reactor shield wall 3 is formed by filling concrete 26 between a steel plate 24 inside the reactor shield wall and a steel plate 25 outside the reactor shield wall, and a column 27 is installed about every 30 degrees. The column 27 includes a steel plate 24 inside the reactor shield wall and a steel plate 25 outside the reactor shield wall.
And welded connection.

In Step C, the existing reactor shield wall is cut. At this time, if the column 27 is cut, there is a problem that the vertical load transfer function of the reactor shield wall is lost and the column strength is reduced. Therefore, it is necessary to surely restore the vertical load transfer function between the column of the reactor shield wall left as the base and the column of the new reactor shield wall mounted thereon.

As shown in FIG. 5, the reactor shield wall 3 has
Nozzle openings 28 and 29 of various nozzles are provided. The core region in the reactor pressure vessel 2 is located above the lower nozzle opening 29. Therefore, when the reactor pressure vessel 2 is replaced and the reactor pressure vessel and the reactor shield wall are unified and carried out, the reactor pressure vessel 2 is cut off at a position below the lower nozzle opening 29, and the reactor pressure vessel 2 above the lower nozzle opening 29 is cut off. When carried out integrally with the shielding wall, the core region in the reactor pressure vessel 2 can be shielded, so that a sufficient shielding effect can be expected.
On the other hand, a radial beam 37 is provided below the reactor shield wall 3.
When the radial beam 37 is also removed and restored again, the work inside the containment vessel increases. Therefore, as shown in FIG. 5, a range 30 of a desired cutting position from the upper side of the radial beam 37 to the lower side of the lower nozzle opening 29 is provided.
At any one of the positions.

In parallel with the cutting operation, various supports connected to the reactor pressure vessel 2 and the reactor shield wall 3 are cut off, and the reactor pressure vessel and the reactor shield wall in the next step D are connected. Prepare for removal.

FIG. 7 is a longitudinal sectional view showing a state in which an existing reactor pressure vessel and a reactor shield wall are integrated and carried out of a reactor building. In Step D, the existing reactor pressure vessel and the existing reactor shield wall are unloaded. Large lifting machine 3
1, the reactor shield wall 3 and the reactor pressure vessel 2 above the cut lower nozzle opening are connected to the reactor building opening 32
Out of the reactor building 33 as a unit.

FIG. 8 is a perspective view for explaining the hanging operation of the upper surface of the reactor shield wall left as a base. Step E
Then, the upper surface of the reactor shield wall left as a base is removed.

FIG. 9 is a view showing a state in which a plurality of connection lids are welded to the upper surface of the reactor shield wall after suspension. In step F, a connection lid is mounted on the reactor shield wall left as a base. That is, as shown in FIG. 9, a plurality of connection lids 35 forming one segment between two columns are formed on a reactor shield wall 34 having a flattened cut surface left in the reactor containment vessel 10. Install. The connection lid 35
It is an iron plate. The inner diameter of the connection lid is smaller than the inner diameter of the reactor shield wall, and the outer diameter of the connection lid is larger than the outer diameter of the reactor shield wall. The side surface of the connection lid 35 may have any shape as long as the upper surface of the column and the side surface of the connection lid can be connected by welding.

In step G, the column, the inner steel plate, the outer steel plate, and the connection lid of the reactor shield wall left as the base are welded. The plurality of connection lids 35 are welded to the column 27 of the reactor shield wall 34 left as a base. Also, a plurality of connection lids 35 and a reactor shield wall 34 left as a base.
Is welded to the steel plate 24 inside the reactor shield wall and the steel plate 25 outside the reactor shield wall.

FIG. 10 is a longitudinal sectional view for explaining the operation of filling the mortar into the lower space of the connection lid. In step H, mortar is filled between the reactor shield wall left as the base and the connection lid. Since the cut surface of the upper surface of the reactor shield wall left as a base has irregularities, mortar is filled through a hole 38 formed in the connection lid 35, and the space under the connection lid 35 is filled and flattened.

In step I, the new reactor shield wall and the reactor pressure vessel are loaded. The new reactor shield wall 3 and the new reactor pressure vessel 2 formed up to the lower nozzle opening 29 are integrally carried into the containment vessel 10. The new reactor shield wall is manufactured in advance at a factory or on site up to the lower nozzle opening 29 and is formed as an integrated structure. That is, at the bottom of the new reactor shield wall, there is a portion that is not filled with concrete so that the column and the connection lid of the new reactor shield wall can be welded in the next step J.

In step I, the new reactor shield wall and the reactor pressure vessel are integrally loaded, but the new reactor shield wall is loaded and fixed on the reactor shield wall left as a base. After that, the new reactor pressure vessel may be carried in.

FIG. 11A is a longitudinal sectional view of the inner steel plate, the outer steel plate, and the concrete portion of the connected new and old reactor shield walls, and FIG. 11B is a vertical sectional view of the connected new and old reactor shield walls. It is a longitudinal cross-sectional view of a column part. In Step J, the column of the new reactor shield wall and the connection lid are welded. The new reactor shield wall 36 is placed on the existing reactor shield wall 34 to which the plurality of connection lids 35 are welded and joined, and the plurality of connection lids 35 and the columns 27 of the new reactor shield wall 36 are welded.

Further, the plurality of connection lids 35 and the steel plate 24 inside the reactor shield wall and the steel plate 25 outside the reactor shield wall of the new reactor shield wall 36 are welded. In this embodiment, the outer steel plate 25 at the lower end of the column of the new reactor shield wall is attached after the welding of the connection lid and the column is completed, and only this portion needs to be filled with mortar.

In step K, the outer steel plate of the new reactor shield wall is attached. After welding the connection lid 35 and the column of the new reactor shield wall 36, the steel plate 25 outside the reactor shield wall at the lower end of the new reactor shield wall is attached.

In step L, the lower part of the new reactor shield wall is filled with mortar.

In the conventional method for constructing the new reactor shield wall 36, the outer steel plate 25 and the inner steel plate 24 are connected to the existing reactor shield wall 34, and then the concrete is placed in both steel plates in the reactor containment vessel. 26 was working. In this conventional construction method, concrete for the entire length of the reactor shield wall is poured into the reactor containment vessel, and the work inside the reactor containment vessel becomes complicated and large-scale, and the concrete filling work requires days. In addition, the work inside the reactor containment vessel 10 is prolonged, for example, the work of welding the structure to the reactor shield wall cannot be performed for about two weeks until the concrete hardens, and the method of replacing the reactor pressure vessel 2 is critical. Had become a pass.

Therefore, in the present invention, the new reactor shield wall 36 which has been poured into concrete and hardened in a factory or the like beforehand.
Is manufactured and delivered as an integral structure, installed on the connection lid and adjusted in position. The connection lid, column, inner steel plate and outer steel plate are welded only at the lower end of the new reactor shield wall, and only this part is welded. Since the mortar is filled, it can be constructed efficiently.

FIG. 12 is a perspective view showing the structure of the entire reactor shield wall after the new reactor shield wall has been welded and connected to the reactor shield wall left as a base. Here, the illustration of the reactor pressure vessel 2 is omitted.

In step M, various pipes connected to the new reactor pressure vessel are welded. Weld and connect each nozzle of the reactor pressure vessel to each system piping and restore.

In step N, fuel and the like are attached.
This work is a reverse procedure of the work of taking out fuel and the like in Step A, and is a work of returning all the fuel to the core as performed in the periodic inspection. After returning all the fuel to the core, the separator 7 is attached, the dryer 6 is attached, the reactor pressure vessel head 5 is attached, and the reactor containment head 4 is attached.

With the above operation procedure, the operation of replacing the reactor pressure vessel and the reactor shield wall has been completed.

According to this embodiment, it is possible to easily align the new reactor shield wall with the reactor shield wall left as a base while securing the column strength of the reactor shield wall, thereby shortening the construction period. At the same time, costs can be reduced.

[0050]

According to the present invention, since the reactor pressure vessel and the reactor shielding wall are carried out as a single unit, it is not necessary to take a separate radiation shielding measure. Also, since a new cylindrical reactor shield wall is carried in, there is no need for a temporary storage space.
Furthermore, it is easy to align the cylindrical new reactor shield wall with the reactor shield wall left as the base, and while maintaining the column strength of the old and new reactor shield walls, the new and old reactor shield wall columns can be Can connect.

When the new reactor shield wall is to be carried in separately from the new reactor pressure vessel, the new reactor shield wall is carried in before the new reactor pressure vessel, and the lower end of the new reactor shield wall is placed. Of the new reactor shield wall and the connection lid can be welded to the connection lid with the inner steel plate and the outer steel plate of the new reactor shield wall. Work in the container becomes easier.

The predetermined height at which the existing reactor shield wall is cut should be lower than the lower nozzle opening of the reactor pressure vessel and higher than the radial beam in the existing reactor shield wall. However, it is desirable from the viewpoint of reducing the total amount of construction work.

If the parts up to the lower nozzle opening of the shield wall of the new reactor are manufactured in advance as an integrated structure at a factory or on site, the amount of work in the reactor containment vessel in which various pipes and supports are complicated is greatly increased. Can be reduced.

In any case, the inside diameter of the ring formed by the connection lid is smaller than the inside diameter of the ring formed by the column of the reactor shielding wall, and the outside diameter of the ring formed by the connection lid is When the diameter is larger than the outer diameter of the ring formed by the column of the shielding wall, the column can be easily aligned.

As a result, the construction period can be shortened and the cost can be reduced while securing the column strength of the reactor shield wall.

[Brief description of the drawings]

FIG. 1 is a flowchart showing one embodiment of a work procedure for unloading / loading a reactor pressure vessel and a reactor shield wall in a method for replacing a reactor pressure vessel according to the present invention.

FIG. 2 is a longitudinal sectional view showing an example of an arrangement of a reactor pressure vessel and a reactor shield wall to be loaded / unloaded in a reactor building.

FIG. 3 is a longitudinal sectional view showing a positional relationship among a reactor shield wall, a reactor pressure vessel, a nozzle and a connection pipe in a reactor containment vessel.

FIG. 4 is a perspective view showing the entire structure of a reactor shield wall.

FIG. 5 is a development view showing the reactor shield wall of FIG. 4 cut out in a vertical direction.

FIG. 6 is a plan sectional view taken along the line AA of FIG. 5;

FIG. 7 is a longitudinal sectional view showing a state in which an existing reactor pressure vessel and a reactor shield wall are integrally carried out outside a reactor building.

FIG. 8 is a perspective view illustrating a hanging operation of the upper surface of the reactor shield wall left as a base.

FIG. 9 is a view showing a state in which a plurality of connection lids are welded to the upper surface of the reactor shield wall after suspension.

FIG. 10 is a longitudinal sectional view for explaining a mortar filling operation into a lower space of the connection lid.

FIG. 11 (A) is a longitudinal sectional view of the inner steel plate, the outer steel plate, and the concrete portion of the connected new and old reactor shielding walls,
(B) is a longitudinal sectional view of the column portion of the new and old reactor shield walls connected.

FIG. 12 is a perspective view showing the entire structure of the reactor shield wall after a new reactor shield wall is welded and connected to the reactor shield wall left as a base.

[Explanation of symbols]

A Fuel removal process B Reactor pressure vessel connection pipe disconnection process C Reactor shield wall cutting process D Transport process of reactor shield wall and reactor pressure vessel E Suspension process of existing reactor shield wall upper surface F Existing reactor Connection lid installation process on shielding wall G Connection lid and column welding process H Existing reactor shielding wall mortar filling process I New reactor shielding wall and reactor pressure vessel loading process J New reactor shielding wall column and connection lid Welding process K Welding process of connection and lid with inner steel plate and outer steel plate of new reactor shield wall L Filling process of mortar under lower part of new reactor shield wall M Welding process of reactor pressure vessel connection pipe N Installation process of fuel 2 Nuclear reactor Pressure vessel 3 Reactor shielding wall 4 Reactor containment vessel head 5 Reactor pressure vessel head 6 Steam dryer 7 Steam-water separator 8 Spent fuel pool 9 Spent fuel rack 10 Raw Reactor containment vessel 11 Main steam nozzle 12 Water supply nozzle 13 Core spray nozzle 14 Recirculated water inlet nozzle 15 Recirculated water outlet nozzle 16 Main steam pipe 17 Water supply pipe 18 Core spray pipe 19 Recirculated water inlet pipe 20 Recirculated water outlet pipe 21 Bulkhead plate 22 Reactor containment stabilizer 23 Refueling bellows 24 Steel plate inside reactor shield wall 25 Steel plate outside reactor shield wall 26 Concrete 27 Column 28 Nozzle opening 29 Lower nozzle opening 30 Desired cutting position range 31 Large lifting machine 32 Reactor building opening 33 Reactor building 34 Existing reactor shield wall 35 Connection lid 36 New reactor shield wall 37 Radial beam 38 hole

Claims (5)

[Claims] 1. A method for replacing a reactor pressure vessel, wherein an existing reactor shield wall is cut in a circumferential direction at a predetermined height and the cut reactor shield wall is replaced with a reactor pressure vessel. The container and the reactor shield wall are unloaded as a unit, and a connection lid for connecting between the columns of the reactor shield wall is mounted on the reactor shield wall left as the base, and the reactor shield wall left as the base is mounted on the reactor shield wall. Column, inner steel plate,
The outer steel plate is welded to the connection lid, mortar is filled between the reactor shield wall left as a base and the connection lid, and the new cylindrical reactor shield wall and the new reactor pressure vessel are loaded. Welding the column at the lower end of the new reactor shield wall and the connection lid; welding the inner steel plate and the outer steel plate of the new reactor shield wall to the connection lid; A method for replacing a reactor pressure vessel, characterized by filling a mortar into a mortar. 2. A method of replacing a reactor pressure vessel, wherein an existing reactor shield wall is cut at a predetermined height in a circumferential direction and the cut reactor shield wall is replaced with a reactor pressure vessel. The container and the reactor shield wall are unloaded as a unit, and a connection lid for connecting between the columns of the reactor shield wall is mounted on the reactor shield wall left as the base, and the reactor shield wall left as the base is mounted on the reactor shield wall. Column, inner steel plate,
Welding the outer steel plate and the connection lid, filling the mortar between the reactor shield wall left as the base and the connection lid, and connecting the cylindrical new reactor shield wall with the new reactor pressure vessel Welding the column at the lower end of the new reactor shield wall and the connection lid; welding the inner steel plate and the outer steel plate of the new reactor shield wall to the connection lid; A method for replacing a reactor pressure vessel, characterized by filling a lower portion of a wall with mortar. 3. The reactor pressure vessel replacement method according to claim 1, wherein a predetermined height at which an existing reactor shielding wall is cut is lower than a lower nozzle opening of the reactor pressure vessel. A method for replacing a reactor pressure vessel, wherein the position is higher than a radial beam in the existing reactor shielding wall. 4. The method for replacing a reactor pressure vessel according to claim 3, wherein the portion up to the lower nozzle opening of the new reactor shield wall is manufactured in advance in a factory or on site as an integrated structure. How to replace the furnace pressure vessel. 5. The reactor pressure vessel replacement method according to claim 1, wherein an inner diameter of a ring formed by the connection lid is formed by a column of the reactor shield wall. A method of replacing a reactor pressure vessel, wherein the outer diameter of the ring formed by the connection lid is smaller than the inner diameter of the ring, and the outer diameter of the ring formed by the column of the reactor shield wall is larger than the outer diameter of the ring. .