JPH01296195A - Reactor building - Google Patents

Abstract

PURPOSE:To improve the safety of a reactor building at the time of an earthquake and make possible the installation of a small-sized reactor on the weak ground by making recess structure of the shape of a reactor building foundation. CONSTITUTION:The shape of a reactor building foundation 4 of a city and suburb type small-sized reactor building 1 is made recess structure. Because the building 1 is buried on the Quaternary period layer ground 6 deeply, frictional force 11 of side face soil is reversely generated against reactor building maximum overturning moment 10 which is generated by an earthquake between the building 1 and the ground 6 by earthquake force 9 which is generated by earthquake energy. The moment 10 which is generated in the building 1 by the frictional force 11 reduces the influence on the building 1. Ground reaction 12 is uniformly applied thereon by making recess structure of the shape of the building, the foundation 4 can obtain high earthquakeproof in structure strength and its stability can be improved even if there is the nature of the soil which is weak.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a nuclear reactor building, and is particularly suitable for improving the stability of a nuclear reactor building in the event of an earthquake in a location on soft ground (Quaternary layer). Regarding the shape of the reactor building foundation with high earthquake resistance.

[Conventional technology]

In conventional nuclear power generation facilities. The basic shape of the reactor building was either a flat plate or a structure with a protruding central part to improve the ground contact ratio, as described in the Atomic Crab Science Test Center PR pamphlet and shown in Figure 2.

[Problem to be solved by the invention]

The above-mentioned conventional technology has a rock mass (third
It is assumed that important nuclear power generation equipment, especially the reactor building 1, will be installed on the 7th layer, but the ground supporting the reactor building foundation 4 is soft and subject to large deformation during earthquakes. No consideration was given to the location of the ground where such behavior would occur, and there was a problem that the stability of the reactor building 1 would be reduced in the event of an earthquake. In Fig. 2, 2 is the containment vessel, 3 is the pressure vessel, 5 is the surface ground, and 8 is the spent fuel pool.

The purpose of the present invention is to improve the safety of reactor buildings in the event of an earthquake, and to construct highly earthquake-resistant reactor buildings in small reactors installed in urban areas where it is difficult to obtain rock with sufficient hardness and spread. The purpose is to provide a basic shape and make it possible to install a small furnace in soft ground (Quaternary layer).

[Means to solve the problem]

The above objective is achieved by ensuring the stability of the reactor building in the event of an earthquake by making the reactor building foundation a concave structure and burying the reactor building (semi-underground type).

[Effect]

The operation of the present invention for solving the problems in the conventional example will be specifically explained below.

The nuclear reactor building of the small urban reactor that is the subject of this invention is made of reinforced concrete, which is extremely strong compared to general buildings due to radiation interference among the various facilities of a nuclear power plant. The weight will increase accordingly. Therefore, the foundation ground supporting the reactor building is required to have a large allowable strength.

However, in the suburbs of cities where small reactors are to be installed, it is extremely difficult to find rock such as Tertiary layered ground, and it is necessary to install the small reactor on soft ground such as Quaternary layered ground.

Figures 4 and 5 show the concept of considering the stability of conventional reactor buildings during earthquakes. The conventional reactor building 1 is installed on the rock called the Tertiary layer ground 7, and when it receives a horizontal seismic force, as shown in Fig. 5, the reactor building maximum overturning moment M+10 generated by the seismic force 9 As shown in FIG. 4, there were cases in which the reactor building 1 lifted up and the stability of the reactor building 1 was impaired. In this case, in order to reduce the maximum overturning moment MslO of the reactor building that occurs during an earthquake, a measure was adopted to widen the foundation shape of the reactor building 1, and the reactor building of the current 1100 MeW class nuclear power generation facility has a size of approximately 80 m x 80 m. ing.

Next, FIGS. 6 and 7 show the concept of studying the stability during an earthquake when a conventional reactor building is installed on soft ground called the Quaternary layer 6. When receiving a horizontal seismic force, the reactor building 1 rises as shown in FIG. 6 due to the reactor building maximum overturning moment hM210 generated by the seismic force 9 as shown in FIG. 7. In this case, since the foundation ground that supports the reactor building 1 is soft ground, the allowable bearing capacity of the ground is low, the supporting ground causes elastic deformation, and the reactor building 1 is prone to overturn, resulting in poor stability during an earthquake. The problem arises that it is lower than in the Tertiary layer location.

In order to solve such problems in the location of the Quaternary layer (soft ground), in the present invention, the building foundation has a concave structure,
By burying the reactor building 1 (semi-underground type), we are trying to increase the safety of the building in the event of an earthquake. FIG. 3 shows the concept of studying the stability of the reactor building 1 during an earthquake in the present invention.

In the reactor building 1 according to the present invention, the reactor building foundation has a concave structure and is buried, so when an earthquake force acts, a maximum overturning moment Mo1O of the reactor building occurs, and the building is about to overturn. Also, the frictional resistance force 11 generated between the building and the ground acts on the side of the building in the opposite direction to the overturning direction, reducing the overturning force. In addition, by making the building shape a concave PT structure, the shape itself is difficult to overturn, and by expanding the bottom area of the building foundation, the required building foundation bottom area for the maximum overturning moment Mo of the reactor building is reduced. However, because the building foundation has a concave structure, even if the supporting ground is elastically or plastically deformed, the ground reaction force can be evenly received by the building foundation, which has a concave structure, and the reactor building will be protected during an earthquake. Control foundation uplift.

〔Example〕

Below, embodiments of the present invention will be explained based on the above principle of operation with reference to the drawings.

FIG. 1 shows the installation situation of a reactor building of a small suburban reactor according to the present invention.

In this figure, a reactor building 1, a reactor containment vessel 2, a reactor pressure vessel 3. The spent fuel pool 8 is supported by the reactor building foundation 4.

Further, the reactor building 1 is installed semi-underground in the quaternary layered ground 6 on the tertiary layered ground 7 which has sufficient rigidity. In the suburbs of cities, the Tertiary layer ground is often located deeper than the ground surface, resulting in the building-ground configuration shown in this figure.

Therefore, during an earthquake, the energy of the earthquake is transferred to the Tertiary layer ground7.
, propagates to the Quaternary layer ground 6 and the surface ground 5, and is input from the reactor building foundation 4 and the side of the reactor building 1,
It is transmitted to the reactor containment vessel 2 and the reactor pressure vessel 3.

Figure 3 shows the reactor building 1 and reactor building foundation 4 in Figure 1.
and surface ground 5, Quaternary layered ground 6, and Tertiary layered ground 7
Focusing on the behavior of the building-ground during an earthquake, the maximum overturning moment of the reactor building is 10, and the frictional resistance force on the side surface is 11.
, and the ground reaction force 12 are used.

In the event of an earthquake, the energy of the earthquake propagates to the tertiary layer ground 7, the quaternary layer ground 6, and the surface layer 5, and is input from the reactor building foundation 4 and the side of the reactor building 1, Equipment installed on reactor building foundation 4 and reactor building 1
It spreads to equipment installed on each floor of the building.

These seismic energies input into the reactor building 1 act as seismic force 9 on the center of gravity of the reactor building 1 .

The earthquake force 9 generated in this way generates a maximum overturning moment 10 in the reactor building 1, which acts to rotate the reactor building 1 like a weight. Since the Quaternary layer ground 6, which is the supporting ground, is a soft ground, it easily undergoes elastic deformation or plastic deformation depending on the magnitude of seismic energy.

This deformation of the Quaternary layer ground 6 makes the reactor building 1 more likely to fall over, but since the shape of the reactor building foundation 4 is a concave structure, the shape itself makes it difficult to fall over.

■Ground reaction force 12 is applied evenly.

■The area of contact between the reactor building foundation 4 and the Quaternary layer ground 6 has been expanded.

■Earthquake load is reduced by expanding the contact area.

This provides the effect of increasing the resistance of the reactor building foundation 4 to seismic energy.

In addition, since the reactor building 1 is deeply embedded in the Quaternary layer ground 6, the seismic force 9 generated by seismic energy causes an earthquake to occur between the reactor building 1 and the Quaternary layer ground 6. The maximum overturning moment of the reactor building generated by
On the contrary, a frictional resistance force 11 of the side soil is generated. This frictional resistance force 11 on the side surface reduces the influence of the reactor building maximum overturning moment 10 generated in the reactor building 1 on the reactor building 1.

Furthermore, due to the shape and concave structure of the 1M sub-reactor building foundation 4, the ground reaction force 12 is evenly applied. By applying the ground reaction force 12 evenly, the reactor building foundation 4 has high earthquake resistance in terms of structure and strength, and the reactor building 1 can maintain its function as an important facility during an earthquake. This is possible even in the soft ground of the Quaternary period layer 6.

In this way, by making the shape of the reactor building foundation 4 of the reactor building 1 of a small urban reactor into a concave structure, (1) the quaternary layer ground 6 of the soft ground that is the supporting ground and the reactor building By equalizing the ground reaction force with the foundation 4, the stability of the reactor building 1 in the event of an earthquake is increased, and the structural
It has high earthquake resistance in terms of strength.

(2) By increasing the resistance of the reactor building foundation 4 against the reactor building maximum overturning moment 10 during an earthquake, and by the frictional resistance force 11 of the side soil acting in the opposite direction to the reactor building maximum overturning moment 10, during an earthquake The stability of the reactor building 1 is improved.

Next, a study will be presented of the building stability during an earthquake of a reactor building with a foundation shape according to the present invention and a reactor building with a conventional foundation shape.

FIG. 8 shows that the reactor building 1 having the basic shape according to the present invention is subjected to a maximum overturning moment 10 due to an earthquake force. The foundation of the reactor building 1 has an upper diameter of 13, a radius of curvature of 15, and is installed on the Tertiary layer ground 7.

FIG. 9 shows that the reactor building 1 with the conventional foundation shape is experiencing a maximum overturning moment 1o due to the earthquake force. The foundation of the reactor building 1 has a diameter of 13, and is installed on the Tertiary layer ground 7 with a planar structure.

In the figure, 14 is the spherical part (diameter) of the building foundation [1].

Here, in order to study and compare the building stability during an earthquake, the reactor building foundation + 11 diameter 13, Tertiary layer ground 7, and reactor building maximum overturning moment 10 are considered as the same conditions.

Calculation formula for grounding ratio (Architectural foundation structure design standards/Explanation PP,
187-188) is as follows: a) Rectangular foundation j) When the neutral axis is outside the base Figure 19.4. In (b), in order for oXn≧L obtained from equation (19, 3), eiL<1/6,
Also, from equation (19.4), it can be seen that α increases linearly with the eccentricity eiL.

ii) When the neutral axis is within the bottom surface, that is, when eiL>1/6, as is clear from Figure 19.4(c), the load P acts at a point x0/3 from the compression edge. So, G,=B xnl/2. It is obtained from A=BL.

Here, the grounding ratio, which indicates the stability of the building during an earthquake, is (19,
From formula 5), the ground contact ratio η = x n / Q xn: Neutral axis distance (m) Q: Ground contact length (m).

Here, if the ground contact length Q is found.

Overturning moment Mc = -NQ N: Vertical force (fon) Eccentricity e = Mc / N Neutral axis distance Xn is: When the neutral axis is outside the bottom surface When the neutral axis is inside the bottom surface MC when the vertical axis is outside the bottom surface N when the neutral axis is inside the bottom surface Therefore, in order to increase the ground contact ratio even when the neutral axis is shifted outside the bottom surface or inside the bottom surface, the ground contact length Q should be set large.

Here, when the bottom areas of the reactor buildings shown in FIGS. 8 and 9 are determined and the resulting equivalent lengths Q' are compared, the results are as follows.

From Figure 9, the floor area of the conventional reactor building is S o =
-Lφ work.

From FIG. 8, the bottom area of the reactor building with the basic shape of the present invention is: S+=knee (L911-L912) 10 The area N of the SMSM 2 dihedral surface is indicated by the symbol shown in FIG. 10, SM=2π
It becomes rh.

If all are expressed using the radius of curvature R, φ ρo""-R, and Qo'<Ql'. By adopting the basic shape according to the present invention, it is possible to provide a nuclear reactor building with improved ground contact ratio. I can do it.

〔Effect of the invention〕

According to the present invention, it is possible to provide a small urban reactor that can reduce the maximum overturning moment of a building during an earthquake in a site with soft ground.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing the TSM-ground of a nuclear reactor according to an embodiment of the present invention, FIG. 2 is a longitudinal cross-sectional view showing the building-ground of a conventional nuclear reactor, and FIG. Reactor Building - An explanatory diagram showing the behavior of the reactor building during a ground earthquake; Figures 4 to 7 are explanatory diagrams showing the behavior of the foundation of a conventional reactor building;
Figures 8 and 9 are detailed explanatory diagrams of the conventional type and the present invention, and Figure 10
The figure is an explanatory diagram for determining the area of the spherical portion when the present invention is adopted. 1... Reactor building, 2... Reactor containment vessel, 3...
・Reactor pressure vessel, 4... Reactor building foundation, 5... Surface ground, 6... Quaternary layered ground, 7... Tertiary layered ground. Figure 1 Figure 2 Figure 3 Figure 4 Concave Country 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10

Claims (1)

[Scope of Claims] 1. A reactor building of a nuclear power generation facility containing a reactor pressure vessel, a reactor containment vessel, and a spent fuel pool, characterized in that a reactor building foundation with a concave structure is provided. Furnace building.