JPS5863891A - Method of constructing diaphragm floor of reactor container - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Regarding the construction method of A, in particular, when the diaphragm floor is completely made of steel and it is constructed in the containment vessel together with the ring bellows, the diaphragm floor is divided into an axial core floor and a peripheral floor. A method for constructing a diaphragm floor for a nuclear reactor containment vessel, which shortens the construction period and facilitates the installation of the seal bellows by welding and fixing the peripheral floor and the seal bellows in advance. Regarding.

In general, a nuclear reactor containment vessel 1, commonly referred to as a MARK-1 model, as shown in FIG. 1, is known as a nuclear reactor containment vessel. This containment vessel 1 is formed in the shape of a bottomed cylinder with a substantially conical upper part, and a reactor pressure vessel 2 is located in the center of the containment vessel 1.
A pedestal 3 is erected to support the. Inside this containment vessel 1, one end is supported by the pedestal 3 and an intermediate part is supported by a columnar and JP-to 12, and a seal bellows 4 is provided between the other end and the inner wall 1a of the containment vessel 1. Sealed diaphragm floor 5
It is divided into an upper dry well 6 and a lower subregion chamber 7. As shown in FIG. 2, this diaphragm floor 5 has a beam 8 extending radially between the pedestal 3 and the inner wall 1a of the containment vessel to support the weight of the diaphragm floor 5, and a seal plate 9 attached to the upper part of the beam 8. The peripheral edge 5a of the diaphragm 5 and the inner wall 1a of the containment vessel 1 are provided with a seal between the dry well 6 and the subregion chamber 7 along the circumferential direction. A closed annular metallic seal bellows 4 is formed.

By the way, when constructing the diaphragm floor 5 and the seal bellows 4, conventionally, the pedestal 3 and the vertical portion 11a of the containment vessel side wall 11 are first formed, and then one end of the beam 8 is supported by the pedestal 3, and the other is attached to the bottom of the containment vessel. The beam 8 is supported by a column support 12 erected from the base. Then, the containment vessel 101
In order to begin construction work on the erecting of the inclined portion 11b of the first wall 11, the ring-shaped seal pase 14 is lifted up by a crane or the like and temporarily installed on the beam 8, and then the inclined portion 11 of the containment vessel side wall 11 is raised. part 11b and the other end of the beam 8 is connected to the containment vessel inclined part 11 by a Franz 13.
It is supported by the inner wall 1a of b. Thereafter, the seal bellows 4 temporarily installed on the beam 8 is appropriately lifted up, and the seal grating 9 is stretched over the beam 8, and the ends of the seal bellows 4 are attached thereto. Then,
The other end of the bellows 4 is placed on the inner wall 1a of the sloped portion 11b of the containment vessel 1'', and a reinforced concrete slab 10 is cast. After curing the concrete for a considerable period of time, a pressure test was conducted and the diaphragm 70A5 was tested.
had completed its construction.

However, this type of structure and construction method requires time-consuming concrete work such as reinforcing, pouring, and curing.
After the installation work of the seal bellows 4 was completed, the concrete work could not begin until after the installation work of the seal bellows 4 was completed, which forced the construction period of the diamond slam floor 5 to be extended.

Furthermore, when assembling and standing up the sloped part 11b of the containment vessel, the end part 8a of the beam 8 was already located inside the sloped part 11b, so it was very difficult to assemble and stand up the sloped part 11b. .

Furthermore, when welding the one end of the seal bellows 4 to the peripheral edge 5a of the diaphragm floor 5, performing it on-site is much more effective in terms of sealing performance than when welding with high precision in a factory. The welding work itself was difficult.

Therefore, a method of attaching the seal bellows 4 by dividing it into a plurality of parts may be considered, but in this case, the performance of the seal grating 4 would be extremely degraded by welding, so it has not been put into practice.

In view of the above-mentioned problems, the present invention was devised to effectively solve the problems.The purpose of the present invention is to make the diaphragm floor completely made of steel, and to connect the diaphragm floor to the shaft core floor and the peripheral edge. The diaphragm of the reactor containment vessel can be formed separately into a peripheral floor and a seal bellows by welding and fixing the peripheral floor and the seal bellows in advance to shorten the construction period and facilitate the installation of the seal bellows. Provides instructions on how to construct floors.

Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

First, as shown in No. 34, the cylindrical containment vessel 1 is assembled up to the vertical portion 11a of the side wall 11 of the containment vessel, and a cylindrical pedestal for supporting the reactor pressure vessel is installed in the center of the containment vessel 1. 3 will be erected. Next, the peripheral edge portion 14&, to which one end 4a of the annularly shaped metal seal bellows 4 is welded and fixed, is suspended by a crane or the like and temporarily installed on the bottom 1b of the containment vessel 1 or on the temporary stand 20. This peripheral floor 14a constitutes a part of the diaphragm floor 14, and is made of a steel material such as a shaped steel 15a and a thick steel plate 17a stretched thereon in advance in a factory or the like. Axis core floor 1 that will be assembled in the future
4b, and is formed into a ring shape as a separate body, and one end 4a of the seal bellows 4 described above is welded and fixed to this along the circumferential direction, and seal inspection etc. have already been carried out at the factory. ing.

Once the peripheral floor 14a to which the seal bellows 4 is integrally attached is temporarily installed on the bottom 1b or the temporary stand 20, the pedestal 3 is then installed as shown in FIG.
Attach the shaft center floor 14b to. Specifically, one end of a shaped steel 15b constituting the shaft core floor 14b is supported by the pedestal 3, and the other end is supported by a column support 16 erected at the bottom 1b of the containment vessel. They are attached radially, and a thick steel plate 17b is integrally welded and fixed thereon along the circumferential direction of the containment vessel 1. If this shaft center floor 14b is installed, or at the same time as this installation work, the inclined portion 1
Start up and build 1b as appropriate.

At this time, the upper and lower 7 rungs 18a and 18b that support the edge of the peripheral floor 14a, and the upper 7 rungs 1
Only part 8a will be fixed by welding so that it will not become an obstacle to the lifting and installation work of the peripheral floor 14a that will be done in the future. Further, since there are no obstacles inside the inclined portion 11b of the containment vessel side wall 11 and the working space S is formed, this construction work can be easily carried out.

Once the construction of the inclined portion 11b of the side wall 11 of the containment vessel is completed, the peripheral floor 14a integrated with the seal bellows 4 on the bottom 1b of the containment vessel 1 or on the temporary stand 20, as shown in FIG. For installation, use a crane or the like to lift it up to the specified position, and weld the first section steel 15a and the working section steel 15b of the shaft core floor 14b to each other, and also weld the steel plates 17a and 17b attached thereto. Then, the shaft core floor 14b and the peripheral edge floor 14a are attached. At this time, the tangential surfaces of the shaped steels 15a, 15b and the steel plates 17a, 17b are welded together, so that they are tightly attached and firmly attached. (Incidentally, these may be fixed with bolts.) At the same time, the upper end portion 4b of the seal bellows 4 is welded and fixed to the inner wall 1a of the inclined portion 11b of the side wall 11 of the containment vessel along its circumferential direction. The construction of the entire diamond 7 ram floor 14 is completed by attaching the lower 7 flange 18b to the inclined portion 11b to support the peripheral floor 14a in the horizontal direction.

Note that a partition wall made of a steel plate may be provided on the lower surface of the diaphragm floor 14 to form an air heat insulating layer within the diaphragm floor 14.

With the structure and method described above, the diaphragm 70A1
4, firstly, the diaphragm floor 14 can be constructed only from steel, and all concrete work such as reinforcing reinforcement, pouring, and curing, which were conventionally required, can be made unnecessary.

In addition, when constructing the diaphragm floor 14, the diaphragm floor 14 is cut and separated into a shaft core floor 14b and a peripheral floor 14a in advance at a factory or the like, and the peripheral floor 14a and the seal bellows 4 are welded and sealed. Since inspection is performed, these can be joined more accurately than on-site welding, and construction can be performed more easily. Therefore, there is no need to wait for the construction of the diamond slam floor to install the seal bellows as in the prior art.

Furthermore, the peripheral portion 70a14 to which the seal bellows 4 is attached
a on the bottom 1b of the containment vessel 1 or on the temporary stand 20 at the beginning of the diaphragm floor 14m erection process, it is possible to start the erection work of the inclined part 11b of the containment vessel side wall 11 at an early stage, and Since there are no obstacles inside this inclined portion 11b, start-up work can be easily performed.

In addition, when welding and joining the shaft center floor 14b and the peripheral floor 14°, for example, cross sections of the same shaped steel are butted and welded, so it is possible to easily and reliably join them. I can do it.

For the reasons described above, the construction period for the diaphragm floor 14 can be significantly shortened.

In short, the method according to the present invention can exhibit the following excellent effects.

(1) Since the peripheral floor and the seal bellows are welded together in advance at a factory or the like, they can be joined more easily and reliably than on-site welding, and reliability can be improved.

(2) Therefore, the peripheral floor and the seal bellows can be attached without waiting for the construction of the diaphragm floor as in the conventional example.

(3) Since the peripheral floor to which the sole bellows was attached was decided to be temporarily installed at the bottom of the containment vessel or on the temporary platform at an early stage, the erection work of the sloped part of the side wall of the containment vessel could be carried out earlier. Furthermore, this work can be done easily and quickly since there are many obstacles inside.

(4) When welding the shaft core floor and the peripheral floor, welding together cross sections of the same steel material,
These can be easily and reliably joined.

(5) The diaphragm floor can be completely made of steel, eliminating the need for concrete work.

(6) Due to the reasons described above, the construction period for the diaphragm floor can be greatly shortened.

[Brief explanation of the drawing]

The first quotient is a schematic vertical cross section showing the inside of the reactor containment vessel, the second quotient is a vertical sectional view to explain the conventional construction method of the diaphragm floor and the 7-level bellows, and the 30th to 54th quotient are the main sections. FIG. 3 is a process diagram for explaining a method for constructing a diaphragm floor according to the invention. Note that 1 is the reactor containment vessel, 1a is the inner wall of the containment vessel,
1b is the bottom of the containment vessel, 3 is the (destal), 4 is the seal bellows, 14 is the diaphragm floor, 14a is the peripheral floor, 14b is the shaft floor, 16 is the concrete, 2
0 is a temporary stand. Patent applicant: Ishikawajima Harima Heavy Industries Co., Ltd. agent, patent attorney Nobuo Kinutani-5:

Claims (1)

[Claims] A diaphragm supported at one end by a pedestal and supported by a column the port in the middle, and with a seal bellows installed between the other end and the inner wall of the containment vessel to form upper and lower divisions within the reactor containment vessel. In the floor construction method, the diaphragm floor is divided into a core floor and a peripheral floor, and one end of the 7-rubellows is attached to the peripheral floor. Temporarily installed at the bottom of the containment vessel or on temporary platform,
Next, after installing the shaft core part 70a on the pedestal and column support in the containment vessel, the peripheral floor is lifted from the bottom or a temporary stand and joined to the shaft core floor, and the other end of the seal bellows is attached to the shaft core part 70a. A method for constructing a diaphragm floor for a nuclear reactor containment vessel, characterized in that the diaphragm floor is constructed by fixing to the inner wall of the containment vessel.