JP2001305263A - Mounting method of shroud support - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mounting method of shroud support capable of facilitating the mounting within a nuclear reactor pressure vessel. SOLUTION: A shroud support 10 for supporting a shroud within the nuclear reactor pressure vessel is carried into the reactor vessel as a plurality of split bodies 22 divided in vertical cutting faces 18 on the outside of the nuclear reactor pressure vessel, and the cutting faces 18 of the split bodies 22 are mutually fixed within the nuclear reactor pressure vessel and formed into the integrated shroud support 10. The integrated shroud support 10 is fixed within the nuclear reactor pressure vessel.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shroud support mounting method for supporting a shroud (isolation wall) in a reactor pressure vessel.

[0002]

2. Description of the Related Art FIG. 6 is a longitudinal sectional view showing an example of a reactor pressure vessel, in which a lid 3 is attached to the upper part of a reactor pressure vessel 1 via a flange 2, and 1, a steam dryer 6 is provided by brackets 4 and 5.
And a steam-water separator 7 and the like, and a fuel assembly 8 extends below the steam-water separator 7. Further, a control rod 8a is provided below the fuel assembly 8.

[0005] A cylindrical shroud 9 for surrounding the outer periphery of the fuel assembly 8 and partitioning the inside of the reactor pressure vessel 1 into and out of the reactor is supported by a shroud support 10.

The shroud support 10 has a cylindrical cylinder portion 11 having an axis in a vertical direction, and a ring-shaped support member fixed to a lower end portion of the cylinder portion 11 and extending horizontally from the outer periphery of the cylinder portion 11. Plate 1
2 and a plurality of legs 13 projecting downward from the lower end of the cylinder portion 11. Further, as shown in FIG. 6, a ring 14 for welding and fixing the different material shroud 9 to the cylinder portion 11 or water outside the shroud 9 is supplied to the reactor pressure vessel 1 from between the legs 13 as shown by arrows. Support plate 12 so that it circulates
In some cases, a hole 15 for mounting a jet pump adapter 16 for a jet pump fixed to a plurality of holes is provided.

FIG. 7 shows a general shroud support 10.
7 (A) shows a ring 14, FIG. 7 (B) shows a cylinder part 11 composed of a plurality of arc-shaped members, and FIG. 7 (C) shows a cylinder part 11 as shown in FIG. After welding the ring 14 to the upper end of 11 as necessary,
A support plate 12 having a shape obtained by dividing a ring into a plurality of parts as shown in (D) is welded to the outer periphery of the lower end of the cylinder part 11 as shown in (E), and then the lower end of the cylinder part 11 is made as shown in (F). A plurality of strip-shaped legs 13 extending downward from the section
To weld.

As shown in FIGS. 7 (D), (E) and (F), a large number of holes 15 are formed in the support plate 12, and these holes 15 are formed as shown in FIG. 7 (G). In some cases, the pipe-shaped jet pump adapter 16 is inserted and welded to the support plate 12. Thus, the shroud support 10 is completed.

FIG. 7 (H) shows a reactor pressure vessel 1 manufactured separately, which has the above-mentioned support plate 12 (D).
Is set so as to match the inner diameter of the inner surface of the reactor pressure vessel 1, and the outer periphery of the support plate 12 is in close contact with the inner surface of the reactor pressure vessel 1. Shroud support 1 completed as shown in (G)
0 from the upper opening of the reactor pressure vessel 1
The inner periphery of the support plate 12 that is in close contact with the inner surface of the reactor pressure vessel 1 is welded to the inner surface of the reactor pressure vessel 1 while the lower end of the leg 13 is inserted into the reactor pressure vessel 1 as shown in FIG. Is welded to the lower end plate 17 having a spherical shape, whereby the assembly of the shroud support 10 is completed.

In recent years, in order to use the nuclear reactor for as long as possible, the equipment contained in the reactor pressure vessel 1, that is, the steam dryer 6 and the steam separator shown in FIG. The replacement of the fuel assembly 8, the shroud 9, the shroud support 10, and the like with new ones is under study. To replace these devices, the lid 3 is removed from the reactor pressure vessel 1, the upper part of the reactor pressure vessel 1 is opened, and the equipment that has been used up to that time is sequentially replaced from the upper devices by the reactor pressure vessel 1. Then, the new equipment is carried into the reactor pressure vessel 1 and installed and fixed inside the reactor pressure vessel 1.

[0009]

However, as described above, the outer diameter of the ring-shaped support plate 12 of the shroud support 10 is set to match the inner diameter of the inner surface of the reactor pressure vessel 1. As shown in FIG. 6, brackets 4 and 5 for supporting the steam dryer 6 and the steam separator 7 protrude from the inner surface of the reactor pressure vessel 1 above the shroud support 10. For this reason, the support plate 12 interferes with the brackets 4 and 5, and the shroud support 10 cannot be taken in and out. Further, in the case of the ABWR type reactor pressure vessel 1, the support plate 12 also interferes with the flange 2 because the flange 2 at the upper part of the reactor pressure vessel 1 protrudes inward.

When the shroud support 10 of a nuclear reactor which has been used up to now is carried out of the reactor pressure vessel 1, the shroud support 10 is set inside the reactor pressure vessel 1.
When the new shroud support 10 is carried into the reactor pressure vessel 1, the support plate 12 is attached to the brackets 4, 5 and even the flange 2. Because of the interference, the completed shroud support 10 cannot be carried into the lower part of the reactor pressure vessel 1 as shown in FIG.

When a new reactor pressure vessel 1 is manufactured, A
Since the upper flange 2 of the BWR type reactor pressure vessel 1 protrudes inward, the shroud support 10 cannot be installed after the final annealing of the reactor pressure vessel 1, so the lid 3 is attached to the reactor pressure vessel. After the shroud support 10 is detached from the reactor pressure vessel 1 and the upper part of the reactor pressure vessel 1 is opened, the shroud support 10 is assembled and attached inside the reactor pressure vessel 1, and then the final annealing is performed. Is subjected to SR heat treatment,
Although the strain is not released, there is a problem that heat is applied to the material and the material is deteriorated, and a stainless steel member cannot be used for the shroud support 10 because the heat of annealing is applied.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a shroud support mounting method that can be easily installed inside a reactor pressure vessel.

[0013]

According to a first aspect of the present invention, there is provided a shroud support mounting method, comprising: a cylindrical cylinder having a vertical axis; A method of mounting a shroud support that includes a ring-shaped support plate that protrudes horizontally, and a plurality of legs that protrude downward from a lower end of the cylinder portion, and that supports the shroud inside the reactor pressure vessel. Then, it is carried into the reactor pressure vessel as a divided body divided into a plurality of parts by a vertical cut surface outside the reactor pressure vessel, and the cut surfaces of the divided bodies are fixed and integrated together inside the reactor pressure vessel. It is characterized in that the shroud support is formed into an integrated shroud support, and the integrated shroud support is fixed inside the reactor pressure vessel.

In the shroud support mounting method according to a second aspect of the present invention, after the integrated shroud support is manufactured outside the reactor pressure vessel, the shroud support is cut into a plurality of pieces by a vertical cut surface. The shroud support mounting method according to claim 1, wherein the divided body is formed by doing so.

Further, in the shroud support mounting method according to the third aspect of the present invention, a divided body having a shape divided into a plurality of sections by a vertical cut surface is manufactured outside the reactor pressure vessel. Item 1 is the shroud support mounting method.

Further, in the shroud support mounting method according to a fourth aspect of the present invention, the cylindrical shroud having a vertical axis, a ring-shaped support plate protruding horizontally from the outer periphery of the cylinder, A method of mounting a shroud support that includes a plurality of legs projecting downward from a lower end of the cylinder portion and that supports a shroud inside a reactor pressure vessel, wherein a vertical Manufacture a divided plate divided into a plurality at the cut surface and carry the divided plate into the reactor pressure vessel,
After fixing the support plate integrated with the divided plate inside the reactor pressure vessel to the inner surface of the reactor pressure vessel,
The assembly assembled by the cylinder portion and the plurality of legs outside the reactor pressure vessel is carried into the reactor pressure vessel, the outer periphery of the cylinder portion is fixed to the integrated support plate, and the leg is attached to the reactor. The shroud support is fixed to the inside of the reactor pressure vessel by being fixed to the pressure vessel.

In any of the shroud support mounting methods according to the first to third aspects of the present invention, the divided shroud support is inserted into the reactor pressure vessel without being hindered by protrusions inside the reactor pressure vessel. It can be carried in and can be installed integrally in the reactor pressure vessel.

In the shroud support mounting method according to the fourth aspect of the present invention, since the support plate having the largest diameter of the shroud support is divided, the reactor pressure vessel is not hindered by a protrusion inside the reactor pressure vessel. And can be installed integrally in the reactor pressure vessel.

[0019]

Embodiments of the present invention will be described below.

FIG. 1 is a plan view showing an example of an embodiment of cutting the shroud support of the method of the present invention, and FIG.
It is a longitudinal cross-sectional view which shows an example of embodiment which fixes the shroud support inside a reactor pressure vessel by the method of this invention, and the part with the same code | symbol as FIG. 6 and FIG. Represents.

In the method of the present invention, a shroud support 10 is manufactured outside the reactor pressure vessel 1 as shown in FIG. The shroud support 10 of FIG. 1 manufactured at this time is exactly the same as the shroud support 10 shown in FIG. 7 (G), and has a ring-like shape from the lower periphery of a cylindrical cylinder portion 11 having a vertical axis. The support plate 12 projects horizontally, and a plurality of legs 1 projecting downward from the lower end of the cylinder portion 11.
3 are integrally manufactured.

Next, the integrally manufactured shroud support 10 is cut (fused) outside the reactor pressure vessel 1 into a plurality of pieces, for example, into three sections at a vertical cutting surface 18 shown in FIG. ) To form the divided body 22.

The divided body 22 thus divided into a plurality of
It can be carried into the lower part of the reactor pressure vessel 1 without interference with members such as the brackets 4 and 5 (see FIGS. 2 and 6) protruding from the inner surface of the reactor pressure vessel 1. Then, the divided body 22 of the shroud support 10 carried into the lower part inside the reactor pressure vessel 1 is assembled as shown in FIG.
After the cut surfaces 18 (see FIG. 1) are welded to each other and formed into an integrated shroud support 10, the lower end of the leg 13 is welded 19 to the lower head plate 17 of the reactor pressure vessel 1 and the inner surface of the reactor pressure vessel 1 is formed. When the outer periphery of the support plate 12 which is in close contact is welded 20 to the inner surface of the reactor pressure vessel 1, the mounting work of the shroud support 10 is completed.

According to another embodiment of the present invention, when the shroud support 10 is manufactured outside the reactor pressure vessel 1, the shroud support 10 is divided into a plurality of parts, for example, three parts by a vertical cut surface 18 shown in FIG. Divided body 2 designed to be separated
2 are individually manufactured, and the divided bodies 22 produced by the division are temporarily assembled outside the reactor pressure vessel 1 to confirm the manufacturing accuracy of the entire shroud support 10.
2 and the divided bodies 22 are individually carried into the lower part of the reactor pressure vessel 1. At this time, the divided body 22 can be carried into the lower part of the reactor pressure vessel 1 without being interfered by members such as the brackets 4 and 5 projecting from the inner surface of the reactor pressure vessel 1.

Each of the divided bodies 22 carried into the lower part of the reactor pressure vessel 1 is assembled as shown in FIG. 2, and the cut surfaces 18 are connected to each other to form an integrated shroud support 10, and then the legs 13 When the welding 19 on the lower end and the welding 20 on the outer periphery of the support plate 12 are performed, the mounting operation of the shroud support 10 is completed.

Next, another embodiment of the present invention will be described.

In this embodiment, the inner diameters of the inner ends of the brackets 4 and 5 shown in FIG. 6 and the inner end of the flange 2 projecting inward in the case of the ABWR type reactor pressure vessel 1 are cylindrical. Focusing on the fact that the outer diameter of the cylindrical cylinder 11 is generally larger than the outer diameter of the cylinder, the cylindrical cylinder 11 having a vertical axis shown in FIG.
Is manufactured integrally (cylindrical) without being divided outside the reactor pressure vessel 1, and a plurality of legs 13 are fixed to the lower portion of the cylinder portion 11 by welding to form an assembly 23 as shown in FIG. It is formed outside the reactor pressure vessel 1. Then, as shown in FIG. 3, the ring-shaped support plate 12 is divided into a plurality of parts, such as three parts, on the vertical cut surface 18 outside the reactor pressure vessel 1, thereby forming a divided plate 12a. The cut surface 18 at this time is the hole 1
When it is set at a location where 5 is drilled, the cutting length is shortened, and the welding length described later is also shortened.

The divided plate 12a can be carried into the lower part of the reactor pressure vessel 1 without being interfered by members protruding from the inner surface of the reactor pressure vessel 1. Split plate 1 down to the inside
After carrying in the reactor pressure vessel 1a, as shown in FIG.
The split plate 12a is welded 20 to a predetermined position on the inner surface, and can be finished into a ring-shaped integral support plate 12 whose outer periphery is closely fixed to the inner surface of the reactor pressure vessel 1.

Next, an assembly 23 consisting of the cylinder portion 11 and the plurality of legs 13 which are integrally formed without being divided outside the reactor pressure vessel 1 is carried into the reactor pressure vessel 1. As described above, the inner diameters of the inner ends of the brackets 4, 5, the flange 2, and the like projecting toward the inside of the reactor pressure vessel 1 are generally larger than the outer diameter of the cylinder portion 11. Then, the cylinder portion 11 is carried into the lower part of the reactor pressure vessel 1 without being interfered by the members protruding from the inner surface of the reactor pressure vessel 1, and is moved to a predetermined position on the inner face of the reactor pressure vessel 1 as described with reference to FIG. The assembly 23 is fitted on the inner diameter side of the support plate 12 fixed by welding 20, and the outer periphery of the lower end of the cylinder portion 11 is welded 2 as shown in FIG.
1 can be fixed to the support plate 12. Subsequently, the lower ends of the plurality of legs 13 fixed to the lower end of the cylinder portion 11 are connected to the lower head 1 of the reactor pressure vessel 1.
When welding 19 is carried out on 7, the mounting work of the shroud support 10 is completed.

The method of the present invention is applied to the existing reactor pressure vessel 1.
The present invention is applicable not only to the case where the inside shroud support 10 is replaced with a new one, but also to the case where the shroud support 10 is attached inside the newly manufactured reactor pressure vessel 1.

[0031]

As described above, according to the first to third aspects of the present invention, since the shroud support is divided, the shroud support can be inserted into the reactor pressure vessel without being hindered by protrusions inside the reactor pressure vessel. There is an effect that the shroud support can be easily carried in and attached.

According to the fourth aspect of the present invention, since the support plate having the largest diameter of the shroud support is divided, the shroud support can be easily provided in the reactor pressure vessel without being hindered by a protrusion inside the reactor pressure vessel. There is an effect that can be carried in and attached.

[Brief description of the drawings]

FIG. 1 is a plan view showing an example of an embodiment for cutting a shroud support according to the method of the present invention.

FIG. 2 is a longitudinal sectional view showing an example of an embodiment in which a shroud support is fixed inside a reactor pressure vessel by the method of the present invention.

FIG. 3 is a plan view showing an example of an embodiment in which a support plate is divided by the method of the present invention.

FIG. 4 is a longitudinal sectional view showing an example of an embodiment in which a support plate is integrated and fixed inside a reactor pressure vessel by the method of the present invention.

FIG. 5 is a longitudinal sectional view showing another example of the embodiment in which the shroud support is fixed inside the reactor pressure vessel by the method of the present invention.

FIG. 6 is a longitudinal sectional view showing an example of a reactor pressure vessel.

FIG. 7 (A) (B) (C) (D) (E) (F) (G)
(H) (I) is a process drawing showing a general shroud support manufacturing procedure and mounting to a reactor pressure vessel.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Reactor pressure vessel 9 Shroud 10 Shroud support 11 Cylinder part 12 Support plate 12a Dividing plate 13 Leg 18 Cutting surface 22 Dividing body 23 Assembly

Continued on the front page (72) Inventor Takashi Ishii 1 Shin-Nakahara-cho, Isogo-ku, Yokohama-shi, Kanagawa Prefecture Inside the Yokohama Engineering Center, Ishikawajima-Harima Heavy Industries, Ltd. (72) Inventor Akio Okabe Shin-Nakahara-cho, Isogo-ku, Yokohama-shi, Kanagawa No. 1 Ishi Kawashima Harima Heavy Industries, Ltd. Yokohama Engineering Center

Claims (4)

[Claims] 1. A cylindrical cylinder portion having a vertical axis, a ring-shaped support plate projecting horizontally from the outer periphery of the cylinder portion, and protruding downward from a lower end portion of the cylinder portion. A method of mounting a shroud support comprising a plurality of legs and supporting a shroud inside a reactor pressure vessel, wherein the reactor pressure vessel is divided into a plurality of divided bodies by a vertical cut surface outside the reactor pressure vessel. It is carried into the reactor pressure vessel, and the cut surfaces of the divided bodies are fixed to each other inside the reactor pressure vessel to form an integrated shroud support, and the integrated shroud support is fixed inside the reactor pressure vessel. Characteristic shroud support mounting method. 2. A split body is formed by manufacturing an integrated shroud support outside a reactor pressure vessel and then cutting the shroud support into a plurality of pieces at a vertical cut surface. Shroud support mounting method described in. 3. The shroud support mounting method according to claim 1, wherein a divided body having a shape divided into a plurality of sections by a vertical cut surface is manufactured outside the reactor pressure vessel. 4. A cylindrical cylinder portion having a vertical axis, a ring-shaped support plate projecting horizontally from the outer periphery of the cylinder portion, and protruding downward from a lower end portion of the cylinder portion. A method for mounting a shroud support that includes a plurality of legs and supports a shroud inside a reactor pressure vessel, wherein a split plate divided into a plurality of pieces is formed on a vertical cut surface outside the reactor pressure vessel to produce the split plate. The plate is carried into the reactor pressure vessel, and the support plate, in which the divided plates are integrated inside the reactor pressure vessel, is fixed to the inner surface of the reactor pressure vessel. The assembly assembled with the plurality of legs is carried into the reactor pressure vessel, and the outer periphery of the cylinder portion is fixed to the integrated support plate, and the legs are connected to the reactor pressure vessel. A shroud support mounting method, characterized in that the shroud support is fixed to a power vessel and the shroud support is fixed inside the reactor pressure vessel.