JPS5870196A - 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 The present invention relates to a diaphragm floor of a nuclear reactor containment vessel.
In particular, the diaphragm floor is made entirely of steel, and a sealed air insulation layer is formed within this structure.
This invention relates to a diaphragm floor regulation for a nuclear reactor containment vessel that can improve the heat insulation effect, simplify assembly work, and significantly shorten the construction period.

Generally, as a nuclear reactor containment vessel, a reactor containment vessel 1 shown in FIG. 1 and commonly referred to as a MARK-II type is known. The containment vessel 1 is formed into a bottomed cylindrical shape 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. The inside of the containment vessel 1 includes a dry well 4 that accommodates the reactor pressure vessel 2, a subregion chamber 5 for suppressing the pressure inside the dry well 4, and a diaphragm floor 6.
The air-water mixture generated at this time is transferred to the sub-region chamber 5 through a vent pipe 7 in case of loss of coolant in the dry well 4. The dry well 4 is guided into the cooling water W inside the dry well 4, where it is cooled and condensed to suppress a rise in pressure inside the dry well 4.

By the way, the diaphragm floor 6 needs to be firmly assembled so as to be able to withstand the large pressure difference that will occur between the dry well 4 and the subregion chamber 5 in the event that the coolant in the dry well 4 is lost. Therefore, it is constructed of steel and concrete as shown in Figure 4. That is, this diaphragm floor 6 is provided by a column support 8 that extends between the inner wall 1a of the containment vessel 1a and the pedestal 3 at appropriate intervals along their circumferential direction, and is erected from the bottom of the containment vessel 1. The main components are the supported beams 9 and the horizontal beams 9a that connect them, and after the seal plate 10 is stretched over these beams, a first insulating concrete 11 and a strong reinforced concrete slab 12 are poured on top of them. The whole structure is constructed by sequentially laminating the second heat insulating concrete 13.

The rigidity of the beam 9, the horizontal beam 9a, and the reinforced concrete slab 12 makes it possible to withstand the differential pressure that would occur between the dry well 4 and the subregion chamber 5 in the event of an accident such as the one described above. .

In addition, 14 is the containment vessel inner wall 1a and the diaphragm floor 6.
QJ! It is an annular seal bellows arranged along the direction.

However, in such a structure, in order to prevent the strength of the reinforced concrete slab 12, which is weak against heat, from deteriorating due to heat transfer from the dry well 4 side, second insulating concrete is installed above and below the reinforced concrete slab 12. 13 and the first heat insulating concrete 11, it also requires a seal plate 10 for pouring these concretes, making the construction work complicated.

In addition, the first and second insulating concrete 11.13
also has the function of a heat insulating material for heating the gap between the dry well 4 and the subregion chamber 5, but since a large load is applied to these, they must be formed with a certain level of strength. Therefore, it has been difficult to create a structure that sufficiently functions as the above-mentioned heat insulating material.

Furthermore, in the above-mentioned concrete work, a series of operations such as reinforcing reinforcement, pouring, and curing must be performed.In particular, if the last step, concrete curing, is not performed sufficiently, the next work step, tz6, must be carried out. It was not possible to move on to the installation of structures inside the drywell, such as the Ipwhip structure, resulting in a prolonged assembly of the diaphragm floor 6 and the resulting damage to the entire facility. Construction period. I was forced to prolong the process.

Moreover, the concrete diaphragm floor 6 cannot avoid deterioration due to long-term use, resulting in the occurrence of cracks, etc., which deteriorates the health of the nuclear facility. there were.

The present invention has been devised to effectively solve the above-mentioned problems, and its purpose is to make the diaphragm floor completely made of steel, and to incorporate To provide a diaphragm floor for a nuclear reactor containment vessel, which forms a hermetically divided air heat insulating layer, thereby improving the heat insulating effect, simplifying assembly work, and greatly shortening the construction period.

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

First, as shown in FIGS. 3 to 5, 3 is a cylindrical pedestal erected at the center of the reactor containment vessel 1 to support the reactor pressure vessel. A diaphragm floor 15, which is a feature of the present invention, is installed between the pedestal slide 3 and the inner wall 1a of the containment vessel. , and a subregion chamber 5 below this.

To explain this specifically, the beam body 16 constituting the diaphragm floor 15 is made of H-beam steel, and one end 16a of this is supported by the mounting part 3a of the pedestal 3, and the other end 16b
are supported on the inner wall 1a of the containment vessel via brackets 17, and are arranged radially along the circumferential direction of the pedestal 3 and the containment vessel 1 at appropriate intervals. Beam body 16
is reliably supported by a column support 8 erected at the bottom of the containment vessel 1. Cross beams 18 are provided between these beam bodies 16 at appropriate intervals along the radial direction of the containment vessel 1. These cross beams 18...
- is made of, for example, H-shaped steel or T-shaped steel, and is welded and fixed to the beam body 16, respectively.

Further, between these cross beams 18, auxiliary beams 19 are arranged along the longitudinal direction at appropriate intervals.
・The gate has been handed over. These auxiliary beams 19 are the horizontal beams 1
8. Web 19. The overall frame C is formed by welding and fixing slightly shorter H-beams or T-beams to the cross beams 18, respectively.

The containment vessel 1 is placed on the frame C or the beam body 16.
A floor 2 made of approximately 40-thick steel plate for forming a vertically sealed section inside the dry well 4 and subregion chamber 5.
0 is integrally welded and fixed, and the rigidity of this steel plate floor 20 and the frame or beam body 16 can withstand the differential pressure between the dry well 4 and the subregion chamber 5 that would occur in the event of an accident. It looks like this @And this steel plate floor 2
Perimeter of 0 $20. An annular seal bellows 1 is attached along the circumferential direction between the container and the inner wall 1a of the containment vessel.
4 is formed to reliably block air convection between the dry well 4 and the subregion chamber 5 through the steel plate floor 20.

On the other hand, the beam body 16 to the frame C also have an air insulation layer 22. Specifically, between the lower flanges 16c of the beam bodies 16 and between the lower flanges 1 of the cross beams 18.
A partition wall 23 made of a steel plate is hung between the two walls 8a, and is fixed by welding, and a sealed air insulation layer 22 is formed between the partition wall 23 and the steel plate floor 20 over the entire area. There is.

This air insulation layer 22 is a web 18b of the cross beam 18.
The box structure is divided into multiple parts along the radial direction of the containment vessel 1, and the space between the dry well 4 and the subregion chamber 5 can be completely insulated. In addition, instead of extending the steel plate floor 20 on the beam body 16, the upper flange 16d of the beam body 16 and the steel plate floor 20 are fixed by butt welding, so that the upper flange 1
6d may be a part of the steel plate floor 20. Furthermore, the strength can be increased by making the bulkhead 23 forming the air heat insulating layer 22 thicker. The diaphragm floor 15 constructed in this manner is appropriately provided with a vent pipe 21 extending through the diaphragm floor 15 and extending from the dry well 4 into the cooling water W in the subregion chamber 5. In addition, the fourth
In the figure, reference numeral 24 denotes a jet defleter for softening the force of the jet flow when the pipe breaks in the dry well 4.

In the event of an accident in the diaphragm floor 15 configured as described above, a mixture of air and water will be generated in the dry well 4, and a large pressure difference will be generated between the interior of the dry well 4 and the subregion chamber 5. Beam 1 for differential pressure
The rigidity of the frame C and the thick steel plate floor 20 can make it durable.

In addition, a steel plate floor 20 integrally welded and fixed to the upper surface of the frame C and a seal bellows 14 installed along the peripheral edge 20a of the floor 20 are provided between the dry well 4 and the subregion chamber 5. are completely sealed and can block air convection between them, and also form an air insulation layer 22 on the diaphragm floor 15, which improves the insulation effect between the dry well 4 and the subregion chamber 5. can be improved.

In addition, since the air insulation layer 22 is formed in the beam body 16 and the frame C structure to form an integrated structure, there is no need to separately form insulation material as in the conventional example, and the construction period can be shortened. .

Furthermore, since the diaphragm floor 15 is completely made of steel, concrete work that was previously required, such as reinforcing, pouring, etc.
It is possible to eliminate the need for curing.

In particular, since there is no longer a need for concrete curing, the diaphragm floor 15 can be cleaned immediately after assembly.
Installation work for structures inside the dry well, such as pipe tube structures, can be started immediately, and the construction period for nuclear facilities can therefore be greatly shortened.

In summary, according to the present invention, the following excellent effects can be achieved.

(1) The diaphragm floor is completely made of steel, and an air insulation layer is built into the beam or frame structure, making these into an integrated structure, making it possible to perform conventional concrete work such as reinforcing, pouring, and curing. This eliminates the need for a series of time-consuming operations such as the above, as well as the need for extensive construction work to form a heat insulating layer, thereby simplifying the assembly work.

(2) In on-site construction, there is no need to adjust the timing of steel structure construction and concrete construction, and construction management and schedule management can be easily performed.

(3) In particular, since there is no longer a need for concrete curing, immediately after the diaphragm floor assembly is completed,
Construction work inside the drywell can begin immediately.

(4) Structures within the dry well, such as pipe tube structures, can be directly welded and fixed to the steel plate floor, making it possible to simplify and rationalize the connection structure.

(5) Therefore, for the reasons stated above, the construction period for nuclear facility construction can be significantly shortened.

(6) The dry well and subregion chamber are airtightly partitioned with a thick steel plate floor to block air convection between them, and an air insulation layer is formed on the diaphragm floor, resulting in excellent insulation effect. can be improved as much as possible.

(7) Unlike conventional concrete diaphragm floors, there is no risk of deterioration and cracking, and the health of nuclear facilities can be improved as much as possible.

(8) Since the structure is simple, it can be easily adopted without making any major changes to the conventional design.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing the inside of the reactor containment vessel, FIG. 2 is a longitudinal sectional view showing a conventional diaphragm floor in the reactor containment vessel, and FIG. 3 is a diaphragm floor according to a preferred embodiment of the present invention. FIG. 4 is a cross-sectional view taken along the line ■--■ in FIG. 3, and FIG. 5 is a cross-sectional view taken along the line ■--V in FIG. In addition, in the figure, 1 is the reactor containment vessel, 1a is the inner wall of the containment vessel,
2 is a reactor pressure vessel, 3 is a pedestal, 4 is a dry well, 5 is a subregion chamber, 15 is a diaphragm floor, 16 is a beam body, 20 is a steel plate floor, 22 is an air insulation layer, and 23 is a partition wall. Patent Applicant: Nobuo Kinutani, Patent Attorney, Ishikawajima-Harima Heavy Industries Co., Ltd.

Claims (1)

[Claims] Inside the reactor containment vessel, which has a pedestal erected in the center to support the reactor pressure vessel, is a dry well that accommodates the reactor pressure vessel, and a subregion chamber that suppresses the pressure within the dry well. In the diaphragm floor, which is divided into two sections, a steel beam is provided between the inner wall of the containment vessel and the pedestal, and a steel beam is integrally welded and stretched over the beam. A steel plate floor is provided at the lower part of the beam body to block air convection between the well and the sub-region chamber and to form a hermetically sealed compartment, and the dry cell is sealed between the steel plate floor and the dry cell. A diaphragm floor for a nuclear reactor containment vessel, comprising a partition wall made of a steel plate that partitions and forms an air insulation layer for insulating between a well and a subregion chamber.