Reactor containment vessel

Abstract

To provide a nuclear reactor storage container that can prevent bending of an inside steel plate because of the back pressure of vapor from a concrete layer between an inside steel plate and an outside steel plate.SOLUTION: The nuclear reactor storage container includes: a first layer made of a steel plate; a second layer made of concrete, provided on the outside of the first layer; and a third layer made of a steel plate, provided on the outside of the second layer. There is a space unit with its upper part released, between a first layer and a second layer of a part in the inside of the nuclear reactor storage container which is in contact with an upper dry well.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a reactor containment vessel having an SC structure.

Background Art

[0002] In next-generation reactors, it is promising to adopt an SC structure containment vessel (SCCV) in which an SC structure integrating a steel plate and concrete with studs is applied to the reactor containment vessel from the viewpoints of labor saving in on-site construction and shortening of the construction period.

[0003] Patent Document 1 aims to provide a reactor containment vessel that can improve workability during construction and reduce the occurrence of cracks and fractures in the inner steel plate even during an accident, thereby ensuring safety. Specifically, in the reactor containment vessel of Patent Document 1, a concrete layer is sandwiched between an inner steel plate and an outer steel plate, and grooves are formed in the inner steel plate. By the deformation of these grooves, the thermal stress generated in the inner steel plate is alleviated, and the occurrence of cracks and fractures in the inner steel plate and the concrete is prevented.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In SCCV, the temperature conditions during an accident are severe (about 200°C), and the inner steel plate in the upper drywell part may buckle due to the thrust force of the steel plate. Therefore, there are problems that the pitch of the studs needs to be narrowed, a steel plate with higher strength needs to be used, and a steam venting mechanism is required to prevent the buckling of the inner steel plate due to the back pressure of steam from the concrete layer between the inner steel plate and the outer steel plate.

[0006] In the reactor containment vessel of Patent Document 1, as described above, since grooves are formed in the inner steel plate, the thermal strain generated in the inner steel plate can be alleviated. However, in the reactor containment vessel of Patent Document 1, since the space between the inner steel plate with grooves formed therein and the concrete layer is a closed space, the back pressure of the steam from the concrete layer cannot be released, and there is a risk that buckling may occur in the inner steel plate due to the back pressure of the steam.

[0007] In order to solve the above-described problems, the present invention provides a reactor containment vessel capable of preventing buckling of the inner steel plate due to the back pressure of steam from the concrete layer between the inner steel plate and the outer steel plate.

[0008] Also, the above object of the present invention and other objects and novel features of the present invention will be clarified by the description of this specification and the accompanying drawings.

Means for Solving the Problems

[0009] The reactor containment vessel of the present invention is a reactor containment vessel including a first layer composed of a steel plate, a second layer provided outside the first layer and composed of concrete, and a third layer provided outside the second layer and composed of a steel plate. And, in the reactor containment vessel of the present invention, there is a space portion with an open upper part between the first layer and the second layer at a portion in contact with the upper drywell inside the reactor containment vessel. There exists, and the first layer in the portion in contact with the upper dry well is separated from the second layer due to the existence of a space portion and is not in contact with the second layer. The first layer in the portion other than the portion in contact with the upper dry well is in contact with the second layer.

Effects of the Invention

[0010] According to the reactor containment vessel of the present invention described above, since there is a space portion with an open upper part between the first layer and the second layer at a portion in contact with the upper drywell, the back pressure of the steam from the concrete of the second layer can be released from the space portion. Thereby, the occurrence of buckling of the inner steel plate due to the back pressure of the steam can be prevented.

[0011] In addition, problems, configurations, and effects other than those described above will be clarified by the description of the following embodiments.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Modes for Carrying Out the Invention

[0013] Hereinafter, embodiments and examples according to the present invention will be described with reference to the text or drawings. However, the structures, materials, and other specific various configurations shown in the present invention are not limited to the embodiments and examples taken up here, and can be appropriately combined and improved without changing the gist. In addition, elements not directly related to the present invention are omitted from the illustration.

[0014] The reactor containment vessel of the present invention is a reactor containment vessel including a first layer made of a steel plate, a second layer provided outside the first layer and made of concrete, and a third layer provided outside the second layer and made of a steel plate. That is, the reactor containment vessel of the present invention has the aforementioned SC structure composed of a steel plate, concrete, and a steel plate.

[0015] And, in the reactor containment vessel of the present invention, there is a space part with an open upper part between the first layer in contact with the upper drywell inside the reactor containment vessel and the second layer.

[0016] According to the configuration of the reactor containment vessel of the present invention, since there is a space part with an open upper part between the first layer in contact with the upper drywell and the second layer, the back pressure of the steam from the concrete of the second layer can be released from the space part. Thereby, the occurrence of buckling of the inner steel plate due to the back pressure of the steam can be prevented.

[0017] In the above-described reactor containment vessel, a sand cushion may be connected below the space outside the first layer, and a drain pipe extending to the outside of the reactor containment vessel may be connected to the sand cushion. In this configuration, the steel plate of the first layer can be cooled with cooling water from the outside, and the used cooling water can be discharged to the outside of the reactor containment vessel through the sand cushion and the drain pipe.

[0018] In the above-described reactor containment vessel, CT steel or FB steel may be arranged outside the first layer so that the steel plate of the first layer is reinforced. In this configuration, the steel plate of the first layer can be reinforced by the CT steel or FB steel arranged outside the first layer, and the seismic performance can be improved.

[0019] In the above-described reactor containment vessel, the space may be provided above the upper dry well and communicate with a cooling pool for storing cooling water. In this configuration, cooling water can be flowed from the cooling pool to the space to cool the steel plate of the first layer.

[0020] In the above configuration, a connection part that can be opened and closed may be further provided between the cooling pool and the space. In this configuration, by controlling the opening and closing of the connection part, the flow rate of the cooling water flowing into the space and the presence or absence of cooling of the steel plate of the first layer by the cooling water can be adjusted.

Example

[0021] Subsequently, a specific example of the reactor containment vessel will be described.

[0022] (Example 1) Hereinafter, the reactor containment vessel of Example 1 will be described with reference to FIGS. 1 to 2. FIG. 1 is a schematic cross-sectional view of the reactor containment vessel of Example 1. FIG. 1 schematically shows a cross-sectional view of a reactor building including the reactor containment vessel 3. Further, FIG. 2 is an enlarged cross-sectional view of the main part of FIG. 1.

[0023] As shown in FIG. 1, the reactor containment vessel 3 of this embodiment has a reactor pressure vessel 2 containing a reactor core 1 therein, and has a three-layer structure including an inner steel plate 11 of the inner first layer, a concrete 12 of the middle second layer, and an outer steel plate 13 of the outer third layer. That is, this reactor containment vessel 3 has the aforementioned SC structure. The inner steel plate 11 of the first layer and the outer steel plate 13 of the third layer are each formed in a cylindrical shape, although not shown in the figure.

[0024] The space between the reactor pressure vessel 2 and the reactor containment vessel 3 is divided into a lower suppression pool 4 and an upper drywell 5, and the suppression pool 4 and the upper drywell 5 are isolated by a diaphragm floor 6 provided therebetween. Cooling water 7 is accommodated at the bottom of the suppression pool 4.

[0025] Further above the upper drywell 5, cooling pools 8, 9, and 10 for accommodating water are provided. Adjacent cooling pools 8, 9, and 10 are isolated by concrete. The cooling pools 8, 9, and 10 are used, for example, as a suppression pool, a spent fuel pool, an equipment temporary placement pool, etc.

[0026] In particular, as shown in FIGS. 1 to 2, the reactor containment vessel 3 of this embodiment has a space portion 14 provided between the inner steel plate 11 of the first layer in contact with the upper drywell 5 and the concrete 12 of the second layer. The space portion 14 has a substantially uniform thickness in the portion within the range shown in the enlarged cross-sectional view of FIG. 2, and becomes thicker towards the top as the diameter of the reactor containment vessel 3 decreases in the upper part. Further, the space portion 14 is different from the closed space portion of the configuration of Patent Document 1 in that the upper part is open.

[0027] In addition, in the reactor containment vessel 3, in the portion in contact with the suppression pool 4 other than the portion in contact with the upper dry well 5, the inner steel plate 11 of the first layer and the concrete 12 of the second layer are in contact with each other without providing a space portion. Further, as shown in FIGS. 1 to 2, the inner steel plate 11 of the first layer is an integral steel plate in which the portion in contact with the upper dry well 5 and the portion in contact with the suppression pool 4 are continuously formed.

[0028] Furthermore, in this embodiment, a connection portion 15 is provided that penetrates the concrete below the cooling pool 9 above the upper dry well 5 and connects the cooling pool 9 and the space portion 14. This connection portion 15 is configured to be openable and closable, such as a valve. Through this connection portion 15, the cooling pool 9 and the space portion 14 communicate with each other.

[0029] By opening the connection portion 15, as shown by the arrow W, the water in the cooling pool 9 can flow along the inner steel plate 11 into the space portion 14, and the inner steel plate 11 can be cooled by this water W. Thereby, in the event of an accident, water can be flowed from the cooling pool 9 to cool the inner steel plate 11. Also, by controlling the opening and closing of the connection portion 15, the flow rate of the water W flowing into the space portion 14 and the presence or absence of cooling of the inner steel plate 11 of the first layer by the water W can be adjusted. In addition, in order to discharge the water that has flowed into the space portion 14, it is preferable to provide a discharge port in the space portion 14 at a location not shown.

[0030] Also, by flowing the water W through the space portion 14, it is possible to cool and seal the penetration portion where the reactor containment vessel 3 (such as the inner steel plate 11) above the diaphragm floor 6 is penetrated by piping (not shown).

[0031] According to this embodiment, since the space portion 14 is provided between the inner steel plate 11 and the concrete 12, the inner steel plate 11 is independent of the concrete 12. As a result, even when the inner steel plate 11 is exposed to a high temperature of about 200 ° C. in the upper dry well, it can be freely deformed with respect to thermal strain, so that buckling due to thermal deformation of the inner steel plate 11 can be prevented. And in this embodiment, since it is not necessary to perform processing such as the groove portion of the configuration of Patent Document 1 on the inner steel plate 11, the manufacturing cost of the inner steel plate 11 can be reduced as compared with the configuration of Patent Document 1 in which the groove portion is provided on the inner steel plate.

[0032] Further, according to this embodiment, since the space portion 14 is provided between the inner steel plate 11 and the concrete 12, the back pressure of the steam from the concrete 12 does not directly act on the inner steel plate 11, so that buckling of the inner steel plate 11 due to the back pressure of the steam can be prevented. In particular, since the space portion 14 is different from the closed space portion of the configuration of Patent Document 1 and the upper portion is widened and released, the back pressure of the steam from the concrete 12 can be released upward.

[0033] Further, according to this embodiment, since the cooling pool 9 provided above the upper dry well 5 for storing cooling water and the space portion 14 communicate with each other through the connection portion 15, the water W in the cooling water pool 9 can be flowed into the space portion 14 through the connection portion 15 to cool the inner steel plate 11.

[0034] Since the above-described operational effects can be obtained, according to this embodiment, it is possible to provide the nuclear containment vessel 3 having all of the heat resistance performance, pressure resistance performance, and cooling performance.

[0035] (Embodiment 2) Next, the nuclear reactor containment vessel of Embodiment 2 will be described. FIG. 3 shows an enlarged cross-sectional view of a main part of the nuclear reactor containment vessel of Embodiment 2. In FIG. 3, the same reference numerals are given to the same components as those of the nuclear reactor containment vessel 3 of Embodiment 1.

[0036] As shown in Fig. 3, the reactor containment vessel 3 of this embodiment is provided with a sand cushion 18 below the space portion 14 in order to discharge the water W that has flowed into the space portion 14, and a drain pipe 19 extends from the sand cushion 18 to the outside of the reactor containment vessel 3. Also, similar to the reactor containment vessel 3 of Embodiment 1 shown in Fig. 2, the space portion 14 has a substantially uniform thickness in the portion within the range shown in the enlarged cross-sectional view of Fig. 2. Since other configurations are the same as those of Embodiment 1 shown in Figs. 1 to 2, duplicate explanations are omitted.

[0037] According to this embodiment, similar to Embodiment 1, a space portion 14 is provided between the inner steel plate 11 and the concrete 12 in the portion facing the upper dry well 5, and the space portion 14 communicates with the cooling pool 9 shown in Fig. 1 via the connection portion 15. Thereby, according to this embodiment, similar to Embodiment 1, a nuclear power containment vessel 3 having all of heat resistance performance, pressure resistance performance, and cooling performance can be provided.

[0038] Also, according to this embodiment, since a sand cushion 18 is provided below the space portion 14 and a drain pipe 19 extends from the sand cushion 18 to the outside of the reactor containment vessel 3, the water that has entered the space portion 14 can be easily discharged through the sand cushion 18 and the drain pipe 19.

[0039] (Modification example) As a modification of the above-described embodiment, a configuration may be adopted in which CT steel or FB steel is provided outside the inner steel plate of the first layer to reinforce the inner steel plate. In the case of this configuration, there is a space portion between the CT steel or FB steel provided outside the inner steel plate of the first layer and the concrete of the second layer. The CT steel or FB steel may be in contact with the inner steel plate or may have a space portion between it and the inner steel plate. By reinforcing the outside of the inner steel plate with CT steel or FB steel, the seismic resistance of the reactor containment vessel can be improved.

[0040] In addition, in Example 1 and Example 2, although the thickness of the space portion 14 was substantially uniform in the portion within the range of the enlarged cross-sectional views of FIGS. 2 and 3, the configuration is not limited to one in which the thickness of the space portion is substantially uniform. For example, it is also possible to adopt a configuration in which the interface between the space portion and the concrete is an inclined surface such that the upper part is thick and the lower part is thin. In the case of this configuration, since the upper part of the space portion is thick, steam can easily escape. Further, since the interface is an inclined surface, similar to the configurations of Example 1 and Example 2 in which the interface is a surface perpendicular to the horizontal plane, the flow of the cooling water is not hindered.

[0041] Also, as another modification to the above-described embodiments, instead of the configuration in which water W is flowed into the space portion 14 through the cooling pool 9 and the connection portion 15, it is also possible to adopt a configuration in which water is flowed into the space portion by another configuration. For example, a configuration in which water is supplied to the space portion through a water supply pipe from another cooling pool or water supply facility is also possible. When the configuration in which water W is flowed into the space portion 14 through the cooling pool 9 and the connection portion 15 is adopted as in the above-described embodiments, it has the advantage that the speed and flow rate of water W can be increased.

[0042] Note that the present invention is not limited to the above-described embodiments and examples, and includes various modifications. For example, each of the above-described embodiments and examples has been described in detail for easy understanding of the present invention, and is not necessarily limited to those having all the configurations described.

Explanation of Reference Numerals

[0043] 1... Core, 2... Reactor Pressure Vessel, 3... Reactor Containment Vessel, 4... Suppression Pool, 5... Upper Drywell, 6... Diaphragm Floor, 7... Cooling Water, 8, 9, 10... Cooling Pools, 11... Inner Steel Plate, 12... Concrete, 13... Outer Steel Plate, 14... Space Portion, 15... Connection Portion, 18... Sand Cushion, 19... Drain Pipe, W... Water

Claims

1. a first layer composed of a steel plate, a second layer provided outside the first layer and composed of concrete, a third layer provided outside the second layer and composed of a steel plate, and a reactor containment vessel comprising: a space portion with an open upper part exists between the first layer and the second layer at a portion in contact with an upper drywell inside the reactor containment vessel, the first layer at the portion in contact with the upper drywell is separated from the second layer due to the existence of the space portion and is not in contact with the second layer, the first layer at a portion other than the portion in contact with the upper drywell is in contact with the second layer Reactor containment vessel.

2. The reactor containment vessel according to claim 1, wherein a sand cushion is connected under the space portion, and a drain pipe extending to the outside of the reactor containment vessel is connected to the sand cushion.

3. The reactor containment vessel according to claim 1, wherein the third layer is in contact with the second layer, and the first layer, the second layer, and the third layer at a portion other than the portion in contact with the upper drywell are integrated.

4. The reactor containment vessel according to claim 1, wherein the space portion communicates with a cooling pool provided above the upper drywell for storing cooling water.

5. The reactor containment vessel according to claim 4, wherein a connectable connection portion is provided between the cooling pool and the space portion.

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