JPH1164565A - Reactor containment vessel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To further improve the soundness of a nuclear reactor by suppressing the internal pressure rise of a container generated by temperature stratification in a pressure suppression chamber pool caused by high temperature gas flowing in from a reactor dry well through a vent pipe at the time of LOCA. SOLUTION: A vent pipe 10 communicated with a dry well 2 and having an opening part in water in a pressure suppression pool 3 is formed in double pipe structure with an outer pipe 10b is arranged outside an external wall of an inner pipe 10a. The upper end 12 and lower end 13 of a void part 11 formed on the outside of the inner pipe 10a and on the inside of the outer pipe 10b are closed, and inert gas or heat insulating material 14 is filled inside. The lower end of the external wall of the outer pipe 10b is provided with a member bent in relation to the outer pipe 10b, or the void part 11 is provided with a void supporting member connected to the external wall of the inner pipe 10a and the internal wall of the outer pipe 10b. Instead of this, it can also be so formed that the upper end of the void part 11 is closed and the lower end is opened into water in the pressure suppression pool 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to a pressure-suppressed type containment vessel in a light water reactor nuclear power plant, and more particularly to a vertical vent in which pool water in a pressure-suppressed chamber can be effectively used as a heat sink even when coolant of a reactor flows out. The present invention relates to a containment vessel having a tube.

[0002]

2. Description of the Related Art FIG. 11 is a schematic sectional view of a conventional Mark-II type reactor containment vessel. The containment vessel is the core 8
Pressure vessel 1, a dry well 2 surrounding the reactor pressure vessel, and a suppression chamber 4 provided below the dry well 2 and having a suppression pool 3 therein.
It is composed of The dry well 2 and the pressure suppression chamber 4 are separated by a diaphragm floor 6. A vertical vent pipe 5 having an open upper end on the upper surface of the diaphragm floor 6 and having a lower end opened in the water of the pressure suppression pool 3 of the pressure suppression chamber 4 is provided. 4 are in contact. A vacuum break valve 7 which is normally closed and is opened when the pressure inside the dry well suddenly rises and exceeds a set value is arranged in the gas phase portion of the vertical vent pipe 5. The arrows in the figure indicate the flow of uncondensed vapor or non-condensable gas.

In such a pressure-suppressed type reactor containment vessel, an event (loss of coolant accumulation) in which coolant flows out of the reactor pressure vessel 1 for some reason.
nt; hereinafter referred to as LOCA. ) Occurs, a large amount of a mixture of high-temperature steam and water is released into the dry well 2,
This mixture is led into the cooling water of the suppression pool 3 in the suppression chamber 4 through the vent pipe 5. Here, the high-temperature steam in the mixture is cooled and condensed, so that an increase in the internal pressure of the containment vessel can be effectively suppressed.

[0004] Safety equipment such as an emergency core cooling system and a containment vessel cooling system provided in a multiplex manner with respect to the reactor containment vessel prevents the core fuel inside the reactor pressure vessel 1 from being damaged even during LOCA. At the same time, it is designed to suppress the temperature rise in the vessel due to decay heat generated in the core for a long time. Furthermore, even if fisson products (hereinafter referred to as FP) are released from the reactor core, the integrity of the containment vessel is maintained high and the leakage of FP to the environment is suppressed to a very small amount by It is designed to ensure high reactor safety.

[0005] Further, although it is an extremely rare phenomenon in terms of probability, even in the event that the cores are damaged or melted due to the failure of a plurality of the safety equipment provided in the above-described manner, the viewpoint of the deep protection. Therefore, the cooling of the damaged core and the suppression of the increase in the internal pressure of the containment vessel are carried out by alternately injecting or spraying the reactor pressure vessel 1 and the dry well 2 using the common system equipment. In this way, it is designed to maintain high safety by maximizing the existing equipment in addition to the safety equipment.

[0006]

In a serious situation such as damage to the reactor core, a certain dry well spray flow rate is required to cool the molten core discharged outside the reactor pressure vessel 1 with water. And However, if a sufficient dry well spray flow rate cannot be ensured, the steam is discharged into the suppression pool water via the vent pipe without being condensed. In this case, the gas discharged from the dry well to the vent pipe has a smaller flow rate and a higher water vapor concentration in the gas than at the time of LOCA.

FIG. 12 is an enlarged sectional view of the vent pipe 5 of the conventional containment vessel shown in FIG. In the conventional containment vessel, the dry well 2
A vertical steel vent pipe is submerged directly into the suppression pool to prevent backflow of gas into the pool. That is, the lower end opening of the vent pipe is set to be lower than the normal water level of the pressure suppression pool. At this time, a part of the gas in the dry well discharged through the vent pipe is condensed on the inner wall surface of the vent pipe because the inner wall of the vent pipe is cooled by the pressure suppression pool water. It is also conceivable that a part of this gas is condensed into high-temperature water, and a part of this water rises along the outer wall surface of the vent pipe.
It is also conceivable that the heat of the condensed high-temperature water adhering to the inner wall surface of the vent pipe is discharged to the suppression pool through the vent pipe, particularly near the water surface of the suppression pool.

As a result, especially when the cooling of the suppression pool water by the residual heat removal system is insufficient, excessive temperature stratification occurs in the suppression pool 3. That is, as the condensation near the inner wall of the vent pipe and the rise of the condensed water rise, the temperature near the water surface of the pressure suppression pool water becomes locally high. FIG. 13 is a graph schematically showing the temperature distribution in the depth direction in the pressure suppression pool near the vertical vent pipe 5 in this case. This shows the relationship between water depth and temperature at a point at a certain distance from the vertical vent pipe 5. According to this, it can be seen that only the surface of the suppression pool water has an excessively high temperature, and the temperature does not rise so much at a point deeper than a certain depth. In this situation, it cannot be said that the entire amount of the suppression pool water is effectively functioning effectively as a heat sink (heat removing means). If the surface of the pool water becomes extremely high due to temperature stratification, steam may be generated on the surface of the pool water, which may cause an increase in the internal pressure of the containment vessel.

According to the current structure of the containment vessel, the integrity of the reactor is maintained sufficiently high even by these events. However, in order to maintain the high soundness of the reactor even higher than the current one, a structure that suppresses such excessive temperature stratification is required.

SUMMARY OF THE INVENTION The present invention has been made in view of these problems, and in a pressure-suppressed reactor containment vessel having a vertical vent pipe, water vapor condensation on the inner wall surface of the vent pipe is suppressed as much as possible, and condensed high-temperature water The purpose of the present invention is to promote thermal diffusion in the process of ascending the inside of the vent pipe, thereby suppressing the temperature stratification of the suppression pool, and efficiently using the entire amount of the suppression pool water as a heat sink.

[0011]

In order to achieve the above object, the present invention provides a reactor pressure vessel containing a reactor core, a dry well surrounding the reactor pressure vessel, and a position below the dry well. A containment chamber containing a pressure suppression pool, and a vent tube communicating with the drywell and having an opening in the suppression pool water, wherein the vent tube is a first tube; A nuclear reactor containment vessel having a double-pipe structure including a second pipe covering a first pipe. This allows
By suppressing heat transfer inside and outside the vent pipe as compared with a conventional vent pipe, water vapor condensation on the inner wall of the vent pipe is suppressed.

A vent pipe having the double pipe structure is
The configuration is as follows. (1) An upper end and a lower end of a gap formed in a gap between the first pipe and the second pipe are closed, and an inert gas is sealed in the gap. (2) The upper end and the lower end of the gap formed in the gap between the first pipe and the second pipe are closed, and the gap is filled with a heat insulating material. (3) The upper end of the gap formed in the gap between the first pipe and the second pipe is closed and the lower end is opened into the suppression pool water. According to these configurations, heat exchange between the first pipe contacting the high-temperature gas flowing in at the time of LOCA and the second pipe contacting the suppression pool water or the atmosphere in the suppression chamber located above the suppression pipe. Suppress and further suppress water vapor condensation inside the vent pipe.

In the above three cases, by providing a member provided at the lower end of the outer wall of the second pipe and bending the second pipe, most of the pressure suppression pool water is used as a heat sink.

Furthermore, in the above three cases, by providing the gap with a gap support member connected to the outer wall of the first pipe and the inner wall of the second pipe, heat convection in the gap is suppressed and the heat insulating effect is provided. Enhance. Alternatively, by setting the distance between the outer wall of the first pipe and the inner wall of the second pipe at the upper end of the gap larger than the distance at the lower end of the gap,
The heat transfer inside and outside the vent pipe in the gas phase part of the pressure suppression chamber is suppressed, and the formation of a high-temperature water tank near the water surface of the pressure suppression pool is prevented.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below. In this embodiment, the vertical vent pipe has a double-pipe structure in the pressure-suppressed reactor containment vessel shown in FIG. 11, and the inside of the outer pipe of the double pipe and the inner pipe of the double pipe are used. A void is formed on the outside. FIG.
FIG. 2 is an enlarged cross-sectional view illustrating a configuration of a vent pipe according to the containment vessel of the present embodiment. FIG. 2 is a cross-sectional view of FIG.
It is an expanded sectional view of the direction of arrow A.

The vertical vent pipe 10 according to the present embodiment comprises two steel pipes 10a and 10b, and surrounds the inner pipe 10a to form an outer pipe.
A space 11 formed outside the inner tube 10a and inside the outer tube 10b is closed at an upper end 12 and a lower end 13, respectively. An inert gas having a low thermal conductivity is sealed therein. In this case, it is preferable to use, for example, nitrogen gas as the inert gas, but it is not particularly limited to nitrogen gas, and any gas that does not easily condense even at a high temperature may be used.

According to the present embodiment, even when a high-temperature gas containing water vapor or a non-condensable gas flows into the vertical vent pipe 10 from the dry well 2 during the LOCA, the inner pipe 10a of the vent pipe 10
The inner wall, i.e., the contact surface between the inner tube 10a and the hot gas, is not directly cooled by the suppression pool 3. Therefore, the high temperature gas flowing into the vent pipe 10 is hardly cooled when passing through the inner pipe 10a of the vent pipe 10,
Is released into the water of the pressure suppression pool 6 through the lower end of the pool, where it is cooled and condensed for the first time.

In other words, the inert gas sealed in the gap 11 causes the outer pipe 10b of the vent pipe to be cooled by the water in the low-pressure suppression pool 3 and the inner pipe 10a of the vent pipe to be heated by the high-temperature gas flowing in. Block heat transfer between them. On the other hand, in the conventional case shown in FIG. 9, heat is transferred when the gas flows through the vent pipe 5 by the low-temperature pool water outside the vent pipe 5 and the high-temperature gas flowing inside the vent pipe 5. 5
When the high temperature gas is condensed near the inner wall of the vent, and the gas contains a large amount of water vapor, a part of the water vapor may be liquefied and water droplets may adhere to the inner wall of the vent pipe. In the present embodiment, the water vapor condensation on the inner wall of the vent pipe is strictly prevented, and the high-temperature gas is cooled and condensed only in the water in the pressure suppression pool 3 to enhance the cooling effect of the pressure suppression pool 3.
The effective heat sink area of the suppression pool 3 can be increased as compared with the related art.

FIG. 3 shows a vertical vent pipe 5 according to this embodiment.
5 is a graph schematically showing a temperature distribution in the depth direction in the pressure suppression pool in the vicinity of. In the graph, the solid line 31 is for the case of the present embodiment, and the broken line 32 is for the conventional case shown in FIG. According to this, the phenomenon of the temperature stratification in which the surface of the pressure suppression pool 3 conventionally generated by the condensation of the water vapor on the inner wall of the vent pipe becomes excessively high in temperature is sufficiently improved.

That is, in the present embodiment, the vent pipe
10 By preventing water vapor condensation on the inner wall, it prevents the rise of the outside wall of the vent pipe due to the conventional condensed water or the heat transfer to the pool water due to the condensed water on the inner wall of the vent pipe, and suppresses the rise in water temperature near the surface of the pool water can do.
In addition, since the high-temperature steam flows into the pressure suppression pool 3 and is cooled for the first time and diffuses in the pool water, there is almost no temperature difference near and below the surface of the pool water, and the temperature is substantially uniform in the depth direction. Make a distribution.

Therefore, by equalizing the temperature of the pressure suppression pool and preventing the water surface from becoming excessively hot,
It is possible to significantly delay the increase in the pressure inside the containment vessel compared to the related art.

Hereinafter, a second embodiment of the present invention will be described. This embodiment is different from the first embodiment in that
In a horizontal vent pipe having a double pipe structure, a heat insulating material is provided in a gap formed by an outer pipe and an inner pipe of a double pipe. FIG. 4 is an enlarged cross-sectional configuration view showing a vent pipe according to the containment vessel of the present embodiment.

The vertical vent pipe 10 in the present embodiment is composed of two steel pipes 10a and 10b, and surrounds the inner pipe 10a and the outer pipe.
10b, and the gaps 11 formed outside the inner tube 10a and inside the outer tube 10b have upper ends 12b respectively.
The lower end 13 is closed, and the gap 11 is filled with a heat insulating material 14. As the heat insulating material 14,
For example, it is preferable to use asbestos, but other materials having low thermal conductivity may be used.

The heat insulating material 14 prevents heat transfer between the vent pipe outer pipe 10b cooled by water in the low-pressure suppression pool 3 and the vent pipe inner pipe 10a heated by the flowing high-temperature gas. . In this case, a higher heat insulating effect can be obtained as compared with the first embodiment using an inert gas having a low thermal conductivity. Therefore, the effect similar to or more than that of the first embodiment can be obtained by substantially the same operation as that of the first embodiment. By expanding the effective heat sink area of the pressure suppression pool, the pressure inside the containment vessel can be reduced. The rise can be greatly suppressed.

Hereinafter, a third embodiment of the present invention will be described. This embodiment is different from the first embodiment in that
In a horizontal vent pipe having a double pipe structure, a lower end of a gap formed by an outer pipe and an inner pipe of a double pipe is opened to a pressure suppression pool water. FIG. 5 is an enlarged cross-sectional configuration view showing a vent pipe according to the containment vessel of the present embodiment.

The vertical vent pipe 10 in the present embodiment is composed of two steel pipes 10a and 10b, and surrounds the inner pipe 10a and the outer pipe.
A gap 11 formed outside the inner tube 10a and inside the outer tube 10b has an upper end 12 closed, while a lower end 15 is open to water in the pressure suppression pool 3. Have been.

According to the present embodiment, at the initial stage when a high-temperature gas containing water vapor flows into the vent pipe 10 from the dry well 2 during the LOCA, the inside of the gap 11 formed by the inner pipe 10a and the outer pipe 10b. The low-temperature water flowing from the lower end opening 15 causes gas condensation near the inner wall of the vent pipe inner pipe 10a. At this time, since the heat of the high-temperature condensed water near the inner wall of the inner tube 10a is absorbed by the water in the gap 11, the rise in the temperature of the outer wall of the outer tube 10b is suppressed. That is, the high-temperature gas flowing near the inner wall of the inner pipe 10a does not directly contribute to the heating of the suppression pool 3 in the course of the circulation, and as a result, the temperature stratification in the suppression pool 3 does not occur.

That is, by opening the lower ends 15 of the inner pipe 10a and the outer pipe 10b, the vent pipe outer pipe 10b cooled by the water in the low-pressure suppression pool 3 by the water located in the gap 11; The heat transfer between the inside of the vent pipe 10a, which becomes high in temperature due to the inflowing high-temperature gas, is prevented. In this case, a higher heat insulating effect can be obtained as compared with the first embodiment in which an inert gas having a low thermal conductivity is sealed. Therefore, the first
The effect similar to or greater than that of the first embodiment can be obtained by the operation substantially similar to that of the first embodiment. Therefore, it is possible to greatly suppress the rise in the internal pressure of the containment vessel by expanding the effective heat sink area of the pressure suppression pool. Can be.

Hereinafter, a fourth embodiment of the present invention will be described. This embodiment is different from the third embodiment in that
In a horizontal vent pipe having a double pipe structure, a plate is provided at the lower end of the outer wall of the pipe outside the double pipe, the plate being bent outward with respect to this pipe. FIG. 6 is an enlarged sectional view showing a vent pipe according to the containment vessel of the present embodiment, and FIG.
FIG. 7 is a sectional view taken in the direction of arrows BB in FIG. 6.

The vertical vent pipe 10 in the present embodiment is composed of two steel pipes 10a and 10b, and surrounds the inner pipe 10a to form an outer pipe.
10b. At the lower end of the outer wall of the outer tube 10b, there is provided a plate 16 which is bent outward at a substantially right angle to the outer tube 10b. As shown in FIG. 7, the plate 16 is inscribed in the outer tube 10b and is formed in a substantially donut shape. 6 and 7, the plate 16 is connected to the lower end 15 of the vent pipe 10.
Applied to the vent pipe according to the third embodiment that is opened into the water of the suppression pool 3,
Alternatively, it is needless to say that the present invention can be applied to the vent pipe according to the second embodiment. Further, the shape of the plate 16 may be any shape as long as it has a circular hole corresponding to the outer tube 10b inside, and is not particularly limited to a donut shape.

According to the present embodiment, the high-temperature gas containing water vapor flowing into the vent pipe 10 from the dry well 2 at the time of LOCA flows in the direction shown by the arrow in the drawing, and flows out into the water in the pressure suppression pool 3. Suppression pool from vent pipe 10
The high-temperature gas flowing into the inside 3 diffuses around the vent pipe 10 along the plate 16, and in the pressure suppression pool 3,
Diffusion and rise with distance. Thereby, it is possible to prevent the high temperature gas from rising along the outer wall of the vent pipe outer tube 10a, and to condense the high temperature gas while performing heat exchange using a wide range of pool water in the suppression pool 3. Do.

Therefore, the same effect as that of the third embodiment can be obtained, and the same effect as that of the third embodiment can be obtained. In addition, the effective heat sink area of the pressure suppression pool is smaller than that of the third embodiment. By being expanded more,
An increase in the pressure inside the containment vessel can be significantly suppressed.

Hereinafter, a fifth embodiment of the present invention will be described. The present embodiment is directed to a horizontal vent pipe having a double pipe structure according to the first embodiment, in which a gap support is provided in contact with an inner wall of an outer pipe and an outer wall of an inner pipe of the double pipe. A member is formed. FIG. 8 is an enlarged cross-sectional configuration view showing a vent pipe according to the containment vessel of the present embodiment. FIG. 9 is an enlarged cross-sectional view in the direction of arrows CC in FIG.

The vertical vent pipe 10 in the present embodiment is composed of two steel pipes 10a and 10b, and the gaps 11 formed by the inner pipe 10a and the outer pipe 10b are closed at the upper end 12 and the lower end 13, respectively. Is filled with an inert gas having a low thermal conductivity. Further, the inner wall of the outer tube 10b and the inner tube 10
A plurality of gap support members 17 that are in contact with the outer wall of FIG. As shown in FIGS. 8 and 9, the gap support members 17 are provided at a plurality of points in the axial direction along the circumferential direction. In the drawing, the gap support members 17 are provided at four locations in each stage over five stages in the axial direction, but the number of the gap support members 17 is not limited to this.

FIG. 9 shows the gap support members 17a, 17b, 17c, and 17d provided in the cross section in the direction of the arrows CC in FIG. Holes 18a, 18b, 18c, 18d are provided between the gap supporting members 17a, 17b, 17c, 17d. Hole 18
are provided, the internal pressure of the air gap 11a immediately above the four air gap support members 17a,.

The convection of the inert gas between the space 11a immediately above and the space 11b immediately below is prevented to some extent by the space supporting members 17a. That is, in the first embodiment having no gap support member shown in FIG.
The hot gas flowing into the vertical vent pipe during OCA raises the temperature of the inert gas in the void. As a result, convection occurs in the gap 11, and high-temperature gas accumulates above the gap 11,
It is conceivable that the heat insulating effect by the inert gas in this area is reduced. However, in the present embodiment, heat exchange, that is, convection between the spaces 11a, 11b,... In the gap 11 divided by the gap support member hardly occurs.

Therefore, in this embodiment, the same operation and effect as those of the first embodiment can be obtained, and at the same time, in particular, the space 11a
In this case, the rise in the temperature of the inert gas can be suppressed, and the heat insulation effect of the inert gas can be maintained high even during the LOCA. Therefore, the rise in the internal pressure of the containment vessel can be delayed more than in the first embodiment.

The gap supporting member of the present embodiment is
The present invention is also applicable to the second embodiment in which a heat insulating material is provided in 11. Also in this case, substantially the same operation and effect as described above can be expected by suppressing the heat transfer in the vertical direction of the gap 11.

Hereinafter, a sixth embodiment of the present invention will be described. This embodiment is formed inside the outer pipe of the double pipe and outside the inner pipe in the horizontal vent pipe having the double pipe structure in the first embodiment shown in FIG. The thickness of the gap portion 11 is set so as to decrease as going downward. FIG. 10 is an enlarged cross-sectional configuration view showing a vent pipe according to the containment vessel of the present embodiment.

The vertical vent pipe 10 in the present embodiment is composed of two steel pipes 10a and 10b, and the gaps 11 formed by the inner pipe 10a and the outer pipe 10b are closed at the upper end 12 and the lower end 13, respectively. Has a heat insulating material 14 sealed therein. In the figure, the thickness at the gap portion, that is, at the upper end 12 of the heat insulating material 14 is d ₁ , and the lower end 13 is
Is d ₂ . Also, the thickness of the closed portion of the upper end 12 (the distance between the outer wall of the inner tube 10a and the inner wall of the outer tube 10b) is f ₁ ,
The thickness of the lower end 13 closed portion is set to f _2. In the present embodiment, d ₁ > d ₂ and a gap portion, that is, a heat insulating material
The total volume of 14 is set to be substantially equal to that of FIG.

As compared with the second embodiment shown in FIG. 4, d ₁ is set slightly larger than the thickness in FIG.
d ₂ is set smaller than that in FIG. In this embodiment also, the thickness of the inner tube 10a and an outer tube 10b is because it is similar in the upper and lower as in the case of FIG. 4, and has a f _1> f _2.

According to this configuration, the void portion located above the water level of the pressure suppression pool 3, that is, the volume of the heat insulating material is larger than that in the case of FIG. In this way, by increasing the heat insulating effect of the vent pipe 10 particularly on the upper surface of the suppression pool 3, the atmosphere located immediately above the water surface of the suppression pool 3 is suppressed from becoming hot, and only the vicinity of the water surface of the suppression pool is outstanding. And the stratification of the pool water, which becomes high in temperature, can be further suppressed.

It should be noted that the change of the thickness of the gap portion in the present embodiment is not limited to the third embodiment, but can be applied to each of the above embodiments. Also in this case, by suppressing the temperature rise of the atmosphere just above the water surface of the pressure suppression pool 3, the same operation and effect as described above can be expected.

[0044]

As described above, according to the present invention, when a gas having a low flow rate and a high water vapor concentration flows from a dry well into a pressure suppression pool through a vent pipe at the time of an accident, the present invention has been described in connection with the present invention. Because it can prevent water vapor condensation and perform heat exchange with a wide range of suppression pool water, it prevents the formation of a warm water layer near the surface of the suppression pool water and effectively uses the pool water as a heat sink. Suppression of pressure in the containment vessel. Thus, the FP leakage to the environment is suppressed to a sufficiently small amount, so that the soundness of the reactor can be maintained even higher.

[Brief description of the drawings]

FIG. 1 is an enlarged sectional view showing a vent pipe according to a reactor containment vessel according to a first embodiment of the present invention.

FIG. 2 is an enlarged sectional view taken in the direction of arrows AA in FIG.

FIG. 3 is a graph schematically showing a temperature distribution in a depth direction in a pressure suppression pool near a vent pipe according to the first embodiment of the present invention.

FIG. 4 is an enlarged sectional view showing a vent pipe according to a reactor containment vessel according to a second embodiment of the present invention.

FIG. 5 is an enlarged sectional view showing a vent pipe according to a reactor containment vessel of a third embodiment of the present invention.

FIG. 6 is an enlarged sectional view showing a vent pipe according to a reactor containment vessel according to a fourth embodiment of the present invention.

FIG. 7 is an enlarged sectional view taken in the direction of arrows BB in FIG. 6;

FIG. 8 is an enlarged sectional view showing a vent pipe according to a reactor containment vessel according to a fifth embodiment of the present invention.

9 is an enlarged cross-sectional view in the direction of arrows CC in FIG. 8;

FIG. 10 is an enlarged sectional view showing a vent pipe according to a reactor containment vessel according to a sixth embodiment of the present invention.

FIG. 11 is a schematic sectional view of a conventional pressure-suppressed reactor containment vessel.

FIG. 12 is an enlarged sectional view of a vent pipe of the conventional reactor containment vessel shown in FIG.

FIG. 13 is a graph schematically showing a temperature distribution in a depth direction in a pressure suppression pool near a vent pipe of a conventional containment vessel.

[Explanation of symbols]

1 ... Reactor pressure vessel, 2 ... Dry well, 3 ... Suppression pool, 4 ... Wet well, 5,10 ... Vent pipe, 6 ...
Diaphlom floor 7 ... Vacuum release valve, 8 ... Reactor core, 10a ... Vent pipe inner pipe, 10b ... Vent pipe outer pipe, 11 ... Void, 12 ... Top of double vent pipe, 13 ... Bottom of double vent pipe, 14 ... Insulation material, 15: Double vent pipe lower end open part, 16: Plate, 17, 17a, 17b, 17c, 17
d: gap support member, 18a, 18b, 18c, 18d: hole

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Tomohisa Kurita, 1st Toshiba Research and Development Center, Komukai Toshiba, Kawasaki-shi, Kanagawa Prefecture (72) Ryoichi Hamasaki, Ryoichi Hamasaki 8 Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa Address: Toshiba Yokohama Office

Claims (8)

[Claims] 1. A reactor pressure vessel containing a reactor core, a dry well surrounding the reactor pressure vessel, a suppression chamber located below the dry well and containing a suppression pool, and the dry well. A reactor containment vessel in communication with a vent tube having an opening in said suppression pool water, said vent tube comprising a first tube and a second tube covering said first tube. A containment vessel having a tube structure. 2. The containment vessel according to claim 1, wherein an upper end and a lower end of the gap formed in the gap between the first pipe and the second pipe are closed. 3. The containment vessel according to claim 2, wherein an inert gas is sealed in the gap. 4. The containment vessel according to claim 2, wherein a heat insulating material is filled in the gap. 5. A gap formed in a gap between the first pipe and the second pipe, wherein an upper end is closed and a lower end is opened into the pressure suppression pool water. Item 7. A containment vessel according to item 1. 6. The reactor containment vessel according to claim 2, wherein a member that bends with respect to the second pipe is provided at a lower end of an outer wall of the second pipe. 7. The reactor containment according to claim 2, further comprising a gap support member connected to an outer wall of the first pipe and an inner wall of the second pipe in the gap. container. 8. The distance between the outer wall of the first pipe and the inner wall of the second pipe at the upper end of the gap is larger than the distance at the lower end of the gap. The containment vessel according to claim 5.