JPS6318155B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for constructing a diaphragm floor in a nuclear reactor containment vessel.

First, the conventional construction method will be explained with reference to the attached drawings. The diaphragm floor 8 in the reactor containment vessel has a structure as shown in FIG. That is, a reactor containment vessel 3 is provided in a reactor building 1 of a nuclear power plant to house a nuclear reactor 2 and equipment piping for a primary reactor system. The reactor containment vessel 3 is divided into two spaces, an upper and a lower space, with a nuticle section 4 as a boundary. The lower space is called the suppression pool 5, and the upper area is called the dry well 6, which has the role of guiding reactor main steam released during an accident into the dry well to the suppression pool through the vent pipe 7 and condensing it. . The diaphragm floor 8 has the role of separating the suppression pool and the dry well.

Next, a conventional method of constructing a diaphragm floor will be explained. FIGS. 2 and 3 are diagrams showing the structure of the diaphragm floor. Construction of the diaphragm floor consists of reactor containment vessel 3 and reactor foundation 9.
This will be carried out at the same time as the assembly and construction of. In other words, the knuckle portion 4 of the reactor containment vessel 3 and the diaphragm floor support 10 have been completed, and the reactor foundation 9 has been completed.
The diaphragm floor beam 11 is attached when the lower part 9a and part of the upper part 9b are completed. Next, the seal plate 12 is welded over the entire surface of the beam. In this case, there is a vent pipe 7 installed in advance, and a portion of this pipe is cut out and welded. On the other hand, the reactor containment vessel 3 and the reactor foundation upper part 9b will be assembled and constructed further upward and will be completed one by one.

Once welding of the seal plate 12 is completed, it undergoes a predetermined inspection. Next, place the first
Concrete 13 having layered heat insulation properties is poured. After concrete curing is completed, reinforcing steel assembly 1
4. Install the drain pipe 15 and the embedded hardware 16, and then pour the second layer of concrete 17. After curing of the concrete is completed, a second heat insulating material 18 is attached with an adhesive, and then a third heat insulating material 19 is poured. The surface of the concrete 19, which is the third heat insulating material, has a floor slope for drainage of oil and water, so when pouring concrete, set a number of slope rulers and use a trowel etc. to slope the surface according to the slope. The settings are being made. Concrete is poured from the outside of the reactor building through a concrete pressure pipe and pumped by a pump truck into the reactor containment vessel 3. At the same time as the diaphragm floor was completed, the reactor containment vessel 3 was assembled.
Construction of the reactor foundation 9 has been completed, and pressure tests and leakage tests of the entire reactor containment vessel will be conducted.

The conventional method of constructing a diaphragm floor in a reactor containment vessel was as described above, but such a method had the following problems.

In other words, in this conventional method, construction must be carried out in a limited and extremely narrow space within the reactor containment vessel 3, and in addition, the opening at the top of the reactor containment vessel is small due to the structure, so the diaphragm Since mechanical power such as large tower cranes could not be used for the work on the floor, the construction period had to be extremely long because it had to rely on human power.

In addition, it is not desirable from a safety point of view, as it requires simultaneous assembly of the reactor containment vessel and construction of the reactor foundation, as well as up and down work over a long period of time. In addition, a large amount of man-hours and costs are required to install temporary protective structures as a safety measure.

The purpose of the present invention is to eliminate such defects and to provide a method for constructing a diaphragm floor in a reactor containment vessel that significantly shortens the construction period, significantly reduces the number of man-hours, and improves work safety and efficiency. be. The feature of the present invention is that once the diaphragm floor beam in the reactor containment vessel and the seal plate welded to its upper part are completed, the fan-shaped or semicircular block-shaped diaphragm floor manufactured in the factory or on-site can be used for assembly of the reactor containment vessel. A diaphragm floor is constructed by using the gap to transport the block onto the seal plate using a large tower crane, welding the blocks together, and filling only the gaps between the joints and vent pipes with concrete, filling, and installing insulation. It's a method.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 4 is a perspective view of one embodiment of a blocked diaphragm floor 21 used in the present invention.

For example, a fan-shaped formwork (not shown) is assembled and disassembled at another location on the construction site to produce a structure that can be used many times, and the first layer of insulating concrete 13A is first applied to this formwork. Next, reinforcing bars 14A, embedded hardware 16A, hanging ears 24, and connecting members 23 are incorporated, and second layer concrete 17A is poured. Then the second
A second heat insulating material 18A and a third heat insulating concrete 19A are constructed in this order on the layered concrete 17A.

Next, the block-shaped diaphragm floor 2
An example of a construction method using 1 will be explained. FIG. 5 is an explanatory diagram showing a method for constructing a diaphragm floor in a reactor containment vessel according to the present invention.

() First, as mentioned above, a block diaphragm floor is manufactured at a prefabricated factory on the construction site or at an off-site manufacturing factory, and then transported to the installation site according to the process procedure.

() In contrast to () above, at the construction site, the reactor containment vessel was assembled, and the diaphragm floor beam 1 was assembled after the diaphragm floor support 10 and part of the reactor foundation upper part 9b were completed.
1 is lifted by a large tower crane, and then the seal plate 12 is welded onto the diaphragm floor beam. The seal plate undergoes a final inspection.

() Next, place the block diaphragm floor 21 completed in () on the diaphragm floor seal plate completed in () above with hanging ears 2.
Using 4, hang and line up in order. Once all the blocks have been mounted, the connecting members 23 between the blocks are fixed by welding to complete the whole as one diaphragm floor. Drain piping 15, concrete 26, heat insulating material 18B, and heat insulating concrete 19B are installed in the gap 25 between the connections between the blocks and the gap between the vent pipe 7 and the blocked diaphragm floor 21.
The diaphragm floor assembly is completed by incorporating and filling the diaphragm floor.

() During this time, the reactor containment vessel and the reactor foundation will be assembled and constructed at the same time, but since it is an extremely short period of time, the work can be done while temporarily adjusting the area, so there will be almost no problems. Become.

As explained above, the construction period of the diaphragm floor can be significantly shortened by the method of constructing the diaphragm floor in the reactor containment vessel using the blocked diaphragm floor.

As a result, whereas previously the assembly of the reactor containment vessel, the assembly of the reactor foundation, and the construction of the diaphragm floor had to be done in parallel up and down, the construction period has been significantly shortened, so only temporary area adjustments are needed. Be able to perform work safely and efficiently.
In addition, because the opening at the top of the reactor containment vessel was small, large-scale lifting equipment could not be used for work on the diaphragm floor at the bottom. Large lifting equipment can be used to perform work with high efficiency in a short period of time when there is a large opening at a low level.

The construction method using fan-shaped blocked diaphragm floors has been explained above, but the blocked diaphragm floors may also be semicircular, and the method of connecting the blocked diaphragm floors is not partial connection but block diaphragm floors. The periphery of the diaphragm floor may be surrounded by steel material, and the steel material of adjacent blocks may be used all around the diaphragm floor.

[Brief explanation of the drawing]

Figure 1 is a vertical cross-sectional view showing the positional relationship between the conventional reactor building and the reactor containment vessel, Figures 2 and 3 are explanatory diagrams showing the diaphragm floor being constructed using the conventional construction method, and Figure 4 is the main FIG. 5 is a perspective view showing a block-shaped diaphragm floor according to the invention, and FIG. 5 is an explanatory view showing the construction method according to the invention. 1... Reactor building, 3... Reactor containment vessel, 8
...Diaphragm floor, 10...Diaphragm floor support, 12...Seal plate, 21
...Blocked diaphragm floor.

Claims (1)

[Claims] 1. In the construction of a diaphragm floor in the reactor containment vessel of a nuclear power plant, after assembling and welding the diaphragm floor beam and seal plate on the reactor lower foundation and the diaphragm floor support of the reactor containment vessel, two or more The diaphragm floor is constructed by suspending the block-formed diaphragm floor, connecting them, and then filling the connecting parts and gaps in other penetration parts with concrete and installing heat insulating material. Method of constructing a diaphragm floor in a reactor containment vessel.