JPH01169397A - Building foundation structure of nuclear power generation plant - Google Patents

Abstract

PURPOSE:To facilitate setting/anchoring work of a building, by providing a hollow section on a building foundation integrated with a float caison. CONSTITUTION:A foundation base 5 with a hollow section 7 set to reduce the weight thereof carries a nuclear reactor primary containment vessel 8, a reactor pressure vessel pedestal 11, a temporarily built steel frame 10 and the like and is introduced to a building stalling position within a site 2 of a power plant via marine transport from a dock. Here, sea water is injected into a foundation hollow section 7 to increase the overall weight of a building, which is settled and anchored. After the completion of a main construction, the periphery of the building is filled with a filling soil 12 so as to act as a counter weight of the foundation base. This makes the building foundation base concurrently serve as a float caison, thereby facilitating the settling and anchoring work of the building in construction on site with a reduction in the weight of a building body itself during the transportation thereof.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to the foundation structure of an offshore nuclear power plant building, and in particular, the building foundation is constructed by integrating a building foundation and a concrete caisson and installing a hollow part in the building foundation. This article relates to a building foundation structure that facilitates towing and installation, and facilitates transportation during decommissioning after the in-service period.

[Conventional technology]

At a nuclear power plant, excavation and construction work for the building begins once the civil engineering work such as site preparation is completed, and once the construction work reaches a certain stage, generally, the plant equipment is removed once the building foundation work is completed. Installation begins.

In order to shorten this construction work, one effective means is to carry out on-site work such as site preparation work and plant equipment work in parallel.

FIG. 3 shows a conventional method for constructing a nuclear power plant aimed at shortening construction work. 1 is a nuclear power plant building carrying equipment, 2 is a power plant site, 3 is a foundation rock, and 4 is a hollow floating caisson that carries 1 and a building foundation plate 5 and provides buoyancy. FIG. 4 similarly shows a method of providing buoyancy during offshore transportation of the building by enlarging the width of the building base plate 5.

Here, the building frame structure and equipment 1 of the nuclear power plant are installed at a factory or at a dock on the ocean, and then transported on the ocean. Meanwhile, at the power plant site 2, excavation is being carried out to install the building frame structure, and in order to guide it to the building installation position, waterways etc. are used to move the installation position to a state where it is filled with seawater 6. Keep it. After the transported building is guided to a predetermined location, it is transported inside a floating caisson, or, in the case of transporting on the building foundation plate, by injecting seawater 6 onto the foundation plate and then filling it with concrete. The power plant building will be sunk and fixed onto the foundation rock. Therefore, this floating caisson and expanded building foundation ensure the buoyancy of the building, and also serve as a weight by pouring seawater and concrete during sinking and fixing. Furthermore, since the foundation supporting the building will be fixed on the bedrock at the final stage, it will have the same strength and weight as the existing nuclear power plant building foundation from an earthquake-resistant design perspective, and the building frame will also be similar to the existing nuclear power plant building foundation. be equivalent. Therefore, in order to expand the installation range of plant equipment in factories or offshore docks, it is necessary to increase the planar dimensions of the building, or to reduce the weight of the building itself and take measures against buoyancy during transportation. , this point was not taken into account.

[Problem that the invention seeks to solve]

In the conventional nuclear power plant building structure, in order to transport the building frame and equipment constructed at an offshore dock by sea, a concrete or steel caisson is installed at the bottom of the body layer, or a building foundation is installed in place of the caisson installation. It is necessary to increase the size of the plate itself to give it buoyancy for sea transportation, and to consider expanding the transportation route to the site and the power plant construction site. On the other hand, from the perspective of shortening the construction period,
Expanding the range of installation of building frames and equipment at the dock as much as possible will shorten the on-site construction period, thereby shortening the overall construction period. However, expanding the installation range of the building frame and equipment will lead to an increase in the weight loaded during sea transportation.
The conventional method of installing caissons results in excessive caisson dimensions, and the latter method of enlarging the dimensions of the building foundation slab itself increases the stress on the foundation slab due to the increased dimensions of the foundation slab, resulting in an increase in strength. In order to take measures against this problem, the amount of reinforcing bars in the foundation plate increased, which caused a contradiction in that the foundation plate itself became heavier. The relationship between the stress applied to the building foundation and the foundation dimension Q is shown below. This formula also shows that reducing the building foundation dimensions leads to a reduction in stress and a lighter weight of the foundation plate.

ρ: Density of seawater Mmax: Maximum bending moment Qmax: Maximum shearing force Also, in conventional building construction methods, concrete is poured inside the caisson or onto the building foundation in order to sink and fix the building on the bedrock. The building, which requires complicated work such as It doesn't take advantage of its characteristics.

The purpose of the present invention is to reduce the weight of the building frame when the building is transported by sea, and to further shorten the construction period by expanding the range of equipment installation on the upper part of the building. In addition to providing the structure, it also enables a suitable construction method for the on-site construction of the power plant.
Another object of the present invention is to provide a nuclear power plant building basic structure that maintains the stability of the building during its service life and makes use of the building transportation concept at the time of construction even during the decommissioning transportation stage after its service life.

[Solve the problem. means for

The above object is achieved by integrating the nuclear power plant building structural plate and the caisson that provides buoyancy during transportation of the building, and by installing a hollow part in the building foundation plate.

Building foundations in nuclear power plants are, for example, 5 to 7 m thick for reactor buildings and 2 to 3 m thick for turbine buildings, and are solid foundations filled with concrete and reinforcing bars. The thickness of this building foundation slab is determined primarily by the strength of the building during an earthquake, but it also serves as a counterweight to the building overturning moment during an earthquake. On the other hand, when a building is transported by sea, a bending moment and shearing force are applied depending on the building foundation dimensions and the maximum wave height during sea transport, as shown in the above formula, but these stresses are After the building is fixed, the bridge can be supported by reinforcing bars to ensure the strength of the building in the event of an earthquake, specifically the upper and lower reinforcing bars installed within the building foundation. Therefore, the main purpose of the building foundation is determined by the earthquake-resistant design of the building. The foundation plate structure can be achieved by the cross-sectional force of the foundation plate and the tensile strength of the reinforcing bars, and when the building is transported, the maximum wave height during transportation and the stress according to the building foundation dimensions are determined by seismic design. It can be handled by In addition, the role of the building foundation plate as a secondary building is mainly during the service life of the nuclear power plant, and in this regard, it is not limited to the conventionally used concrete, but also any material that enhances the effect of the foundation plate as a counterweight. It is sufficient.

[Effect]

In order to facilitate the transportation of seawater to the building, to mount as many equipment as possible on the building roof for the purpose of shortening the construction process, and to minimize the increase in the building foundation dimensions, it is necessary to reduce the weight of the building frame itself. It is important to aim for For this reason, by creating a building foundation structure that integrates the building frame and a caisson that gives buoyancy to the building, and by installing a hollow section in this building foundation, the building foundation itself can serve as ballast. . Furthermore, since this building's foundation has already been designed to be earthquake resistant, no new construction work such as reinforcement work will be required during building construction. In addition, the work of sinking and fixing the main building after transporting the building to the construction site can be done easily by injecting seawater etc. into the hollow part installed in the building's foundation structure as described above to reduce the weight of the building to more than its buoyancy. You can proceed with your work. After the building has been sunk and fixed, parts of the building frame and equipment that were outside the scope of installation at the factory and dock may be constructed, or in some cases, all installation has been completed at the factory and dock. will enter commercial operation after trial run. After the nuclear power plant is in service, the building will be able to be transported by reversing the procedure used during construction, and the main structures within the power plant, such as the high bends and foundation plates, will not remain, so it will be difficult to decommission the reactor. New power generation facilities can be constructed by reusing the site later.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 and 2, taking a nuclear reactor building as an example.

Figure 1 shows the packaging during transportation to the reactor building. 5 shows the reactor building foundation plate, 7 shows the hollow part installed in the foundation bottle, 9 shows the reactor building upper structure, and Figure 2 shows a cross-sectional view of the reactor building after sinking, fixing, and construction are completed. show.

The reactor building foundation plate 5 will be constructed in a dock separate from the power plant site 2. At this time, a hollow portion 7 is installed in the base plate 5 to take measures to reduce the overall weight.

Reactor-fireway containment vessel 8 and reactor pressure vessel pedestal 11. By reducing weight, it is possible to shorten the construction period and improve constructability. Temporary steel frames 10, etc. can be mounted on the foundation. The base plate carrying these equipment will be transported from the dock by sea to the building installation location within the power plant site 2.

As shown in Figure 2, once the building has been brought to the installation position, seawater is injected into the hollow foundation 7 to increase the weight of the entire building, and the building is sunk and fixed. Furthermore, after the completion of this construction work, the central part of the building will be reclaimed using reclaimed earth, leaving the site conditions exactly the same as those of conventional power plants. The hollow portion 7 of the base bottle is kept filled with seawater even during the period of service, and serves as a counterweight for the base plate. In addition, when decommissioning the reactor after the in-service period, a part of the upper building is dismantled and then the seawater in the hollow part 7 of the base plate is discharged. is easily achieved.

According to this example, since the building foundation plate and the floating caisson are used together, it is possible to reduce the weight of the building frame itself during building transportation, and the construction process for the upper part of the foundation plate can be further shortened. Equipment can be installed. Furthermore, during the on-site construction stage, the building can be easily sunk and secured by injecting seawater into the hollow part of the foundation bottle, and this foundation plate can be used as it is as the building foundation plate during the power plant's service life. Furthermore, after the power plant has been in service, transportation at the time of decommissioning after the in-service period can be easily accomplished by following the steps in reverse to the construction sequence.

〔Effect of the invention〕

According to the present invention, the weight of the building itself during offshore transportation is reduced, and the work of sinking and fixing the building during on-site construction of the building becomes easier.

[Brief explanation of the drawing]

Figures 1 and 2 are cross-sectional views of a building according to an embodiment of the present invention;
FIG. 4 is a diagram showing the ocean transportation of a building according to the prior art. 1...Nuclear power plant building. ≠ 1 of 11 - Machi 90,000 = Ne8, Shigote people 1 and 1z・ Landfill eel 3 eyes

Claims (1)

[Claims] 1. Integrate the nuclear power plant building foundation and floating caisson into one,
A nuclear power plant building foundation structure characterized by a hollow section installed in the building foundation.