JPH02115793A - Atomic reactor containing facility - Google Patents

Abstract

PURPOSE:To eliminate the deflection of the center of gravity of the title facility so as to improve the stability of the structure by separately constituting a pressure suppressing room and upper pool up and down. CONSTITUTION:A reactor pressure vessel 22 houses a reactor core 21 and is surrounded by a dry well 23. An annular upper pool 24 having a rectangular cross section is provided above the dry well 23 and emergency cooling water is stored in the lower section 25 of the dry well 23, with an empty space 26 being formed on the cooling water. The bottom surface 27 of the pool 24 is set to a level higher than the reactor core 21 and the pool 24 and pressure vessel 22 are connected with each other by means of the pipeline 28 of an emergency reactor core cooling system through a valve. A pressure suppressing chamber 29 is provided below the dry well 23 and pressure suppressing water is stored in the lower section 30 of the chamber, with an empty space section 31 being formed on the water. The lower section 30 and dry well 23 are connected with each other through a bent pipe 32 and the space sections 26 and 31 are connected with each other through a connecting pipe 33. Since this atomic reactor containing facility 20 is constituted in such way, the facility 20 has no heavy section at the top and can be reduced in diameter.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a nuclear reactor containment facility installed in a nuclear power plant and accommodating a reactor pressure vessel.

(Prior Art) Generally, a nuclear reactor pressure vessel that houses a reactor core equipped with fuel is housed in a dry well of a nuclear reactor containment vessel. A hypothetical accident within this dry well is a rupture of the primary system piping. In the event of a rupture accident in the secondary system piping, steam and water released into the dry well surrounding the reactor pressure vessel are introduced into the pressure suppression chamber water through the vent pipe. and,
By condensing and cooling steam etc. in this water, energy is absorbed and pressure rise within the dry well is suppressed.

Furthermore, in the case of such an accident, coolant flows out from inside the reactor pressure vessel, exposing the reactor core, which may cause core burnout. For this reason, emergency core cooling equipment is usually provided to inject cooling water into the reactor pressure vessel from a separate route to prevent core burnout. This emergency core equipment normally uses a power source such as a pump to inject cooling water into the reactor pressure vessel, but on the other hand, emergency core equipment uses gravity to inject cooling water without relying on a power source. The concept of a reactor containment vessel equipped with core cooling equipment is shown in Japanese Patent Publication No. 38-16198.

This reactor containment vessel will be explained using FIG. 10. The reactor containment vessel 1 is provided with a dry well 3 housing a reactor pressure vessel 2 and a pressure suppression chamber 4. In the lower part 5 of this pressure suppression chamber 4, a bear is provided at a position higher than the reactor core 8. The pressure suppression chamber 4 and the reactor pressure vessel 2 are connected through a valve 9 and a core cooling system piping 10 .

In such a reactor containment vessel 1, if a rupture accident occurs in the secondary system piping, the steam released into the dry well 3 is introduced into the water via the vent pipe 6 and condensed and cooled. Suppress pressure rise in well 3.

Furthermore, the water stored in the pressure suppression chamber 4 is also used as emergency core cooling water. That is, when coolant flows out from the reactor pressure vessel 2, the valve 9 of the core cooling system piping 10 is opened to introduce cooling water into the reactor pressure vessel 2, thereby preventing burnout of the reactor core 8. At this time, since the bottom part 7 of the pressure suppression chamber 4 is installed higher than the reactor core 8, the introduction is carried out by gravity simply by opening the valve 9, and there is no need for a power source and consideration is given to the failure of these power sources. You can do without it.

(Problem to be Solved by the Invention) However, the amount of water stored in the pressure suppression chamber 4 is limited to the amount used to condense steam released from the dry well 3 in the event of an accident, and the amount used as cooling water for the emergency core cooling equipment. Since it satisfies both the amount to be injected into the pressure vessel 2, the amount is extremely large. Therefore, the reactor containment vessel 1 holds a large amount of weight at the top, resulting in an unstable structure with a high center of gravity.
The seismic load due to the acceleration acting on the geological formation also increases, which poses a safety problem. In addition, in order to compensate for this, the 10 legs of the reactor containment vessel and the base of the reactor building must have a strong structure.

On the other hand, during periodic inspection of the nuclear coupler, operations such as loading and unloading of fuel from the upper cover 11 of the reactor pressure vessel 2 are carried out, and the pressure suppression chamber 4 is used as this work area. However, access to the pressure suppression chamber 4 is environmentally problematic due to many restrictions such as radioactive contamination. In addition, since the working floor level indicated by the symbol A in Fig. 1 is far from the reactor core 8, there was a problem that both workability and reliability were poor during the above-mentioned work. In order to lower the pressure and secure water in the pressure suppression chamber 4, it is necessary to increase the diameter of the reactor containment vessel 1. However, increasing the diameter is disadvantageous against pressure in the event of an accident, and in order to ensure equivalent pressure resistance, the plate thickness of the reactor containment vessel must be increased.

An object of the present invention is to eliminate the unstable structure with a high center of gravity and to obtain a nuclear reactor containment facility with excellent structural soundness and high reliability.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above object, the present invention includes a reactor pressure vessel accommodating a reactor core, a dry well surrounding this reactor pressure vessel, and an outside of this dry well and a an upper pool that is located at a higher position than the reactor core, stores water in the lower part, and has a space in the upper part; emergency core cooling system piping that connects the lower part of the upper pool to the reactor pressure vessel; and the dry well. a pressure suppression chamber located below that stores water in the lower part and has a space in the upper part; a vent pipe that connects the lower part of the pressure suppression chamber to the dry well; and the space in the pressure suppression chamber and the upper pool. A nuclear reactor containment facility is provided, characterized in that it consists of a communication pipe that connects the space between the reactor and the reactor containment facility.

(Function) Since the pressure suppression chamber and the upper pool, which is an emergency core cooling facility, are separated into upper and lower sections, a stable structure can be achieved with no imbalance in the center of gravity.

On the other hand, in the event of a rupture accident in the secondary system piping, the steam released into the drywell is introduced into the water in the pressure suppression chamber from the vent pipe, and the pressure rise is suppressed by condensation cooling.
The non-condensable gas is discharged into the space of the pressure suppression chamber without being condensed. The space of this pressure suppression chamber is connected to the space of the upper pool by a connecting pipe and the space is shared, so the pressure of the non-condensable gas is also transmitted to the space of the upper pool, increasing the pressure effectively. is suppressed. Further, the pressure of the non-condensable gas transmitted to the space of the upper pool through the communication pipe acts like a driving pressure when water from the upper pool is injected into the reactor pressure vessel.

(Example) Hereinafter, an example of the present invention will be described with reference to FIGS. 1 to 9.

FIG. 1 is a longitudinal sectional view showing a first embodiment.

The reactor containment facility 20 is placed in a reactor building (not shown) and has a substantially cylindrical shape with a reactor pressure vessel in the center. Reactor pressure vessel 22 accommodates reactor core 21 and is surrounded by dry well 23 . Above the dry well 23, an upper pool 24 is provided in an annular shape with a rectangular cross section. Emergency core cooling water is stored in the lower part 25 of the upper pool 24, and the upper part of this cooling water forms a space 26. The bottom surface 27 of the upper pool 24 is located higher than the reactor core 21, and the upper pool 24 and the reactor pressure vessel 22 are connected to each other.

It is connected to the emergency core cooling system piping 28 via a valve (not shown). A pressure suppression chamber 29 is provided below the dry well 23 . Water for pressure suppression is stored in the lower part 30 of this pressure suppression chamber 29, and the upper part of this water is a space 31. The lower part 30 of this pressure suppression chamber 29 and the dry well 23 are connected by a vent pipe 32. The space 26 of the upper pool 24 and the space 31 of the pressure suppression chamber 29 are connected by a communication pipe 33.

In the reactor containment facility 20 configured in this way,
A pressure suppression chamber 29 and an upper pool 24 are provided above and below.

Since it is a girder, it is possible to create a stable structure with a lower center of gravity without having to have a large beam at the top. Further, since the diameter of the nuclear reactor containment facility 20 can be made smaller, the construction period can be shortened and restrictions on the site can be reduced. Furthermore, the work floor level B on which work is performed during periodic inspections and the like is closer to the upper cover 34 of the reactor pressure vessel 22, which not only improves work efficiency but also allows work to be performed outside the reactor containment facility 20.

In addition, in the event that an accident occurs in which the coolant in the reactor pressure vessel 22 flows out due to a rupture of the primary system piping (not shown) connected to the reactor pressure vessel 22, the emergency core cooling system piping 28 is equipped with a By opening the valve, the emergency core cooling water stored in the upper pool 24 is injected into the reactor pressure vessel 22 by gravity. At this time, the pressure of steam released into the dry well 23 at the time of the accident is transferred to the upper pool 23 through the vent pipe 32 and further through the connection 4W33.
4 and acts as a driving pressure for injection, so
Injection can be performed more reliably than only by gravity.

Furthermore, since the space 26.31 between the pressure suppression chamber 29 and the upper pool 29 is shared by the communication pipe 33, the space in the pressure suppression chamber 29 is not condensed and cooled by the water stored in the pressure suppression chamber 29. The pressure increase of the non-condensable gas discharged into the section 31 can be efficiently suppressed.

Next, a second embodiment will be described with reference to FIG.

FIG. 2 is a longitudinal sectional view showing the second embodiment.

In the reactor containment facility 20a of the first embodiment, the emergency core cooling water injected into the reactor pressure vessel 22 at the time of the accident leaked into the dry well 23 from a break in the piping. Flooding level of emergency core cooling water in case C
The end of the vent Irf 39 on the dry well 23 side is set higher than that of the vent Irf 39. Since the submergence level C is set higher than the core 21,
can remain submerged at all times. Further, the emergency core cooling water that has flowed into the dry well 23 can be prevented from flowing into the pressure suppression chamber 29 through the vent pipe 39. Therefore, the water capacity of the upper pool 24 can be minimized.

FIG. 3 is a longitudinal sectional view showing the third embodiment.

The reactor containment facility 20b is constructed by lowering the reactor pressure vessel 22 so that the reactor core 21 is lower than the water level of the water contained in the pressure suppression chamber 29 in the reactor containment facility 20 of the first embodiment. Become. Thereby, radiation shielding of the core 21 can be effectively performed by water.

FIG. 4 is a longitudinal sectional view showing the fourth embodiment.

In the reactor containment facility 20c of the first embodiment, the reactor pressure vessel 22 is lowered so that the reactor core 21 is below the water surface of the pressure suppression chamber 29, and at the same time the control rod drive device (not shown) is lowered. It is arranged at the upper part of the reactor pressure vessel 22. Therefore, the water in the pressure suppression chamber 29 causes the core to
1. Radiation shielding can be effectively performed.

FIG. 5 is a longitudinal sectional view showing the fifth embodiment.

In the reactor containment facility 20 of the first embodiment, the reactor containment facility 20d includes a dry well spray 34 that directly sprays the dry well 23 with the emergency core cooling water stored in the upper pool 24. This dry well spray 34 includes a pipe 35 whose one end is connected to the lower part 25 of the upper pool 24 and the other end is connected to the upper part of the dry well 23, a valve (not shown) disposed in the middle of this pipe 35, and and a spray nozzle 36 arranged at the tip on the dry well 23 side.

If emergency core cooling water is sprayed into the dry well 23 by the dry well spray 34 at the time of an accident, the pressure increase in the dry well 23 can be suppressed. A vacuum break valve 37 connecting the space 31 of the pressure suppression chamber 29 and the dry well 23 is provided in the vent pipe 32d, and when the pressure in the dry well 23 falls below a specified value, non-condensable gas is released from the pressure suppression chamber 29 to the dry well 23. to be introduced.

FIG. 6 is a longitudinal sectional view showing the third embodiment.

In the reactor containment facility 20e, the height of the upper pool 24e is lowered, and the diameter is increased to ensure the required volume. Further, the bottom surface 27e of the upper pool 24e is set lower than the top surface 38 of the dry well 23. As a result, the working floor level D is raised to the upper cover 34 of the reactor pressure vessel 22.
Since it can be brought close to , work efficiency can be further improved.

As described above, in the first to sixth embodiments, the upper pool and the pressure suppression chamber are formed in an annular shape along the circumference of the dry well, but the present invention is not limited to this shape. Further, the shape of the reactor containment facility is not limited to a cylindrical shape. For example, a part of an annular upper pool may be sectioned off and used as a fuel pool. Also,
One or more rectangular shapes may be installed.

Next, a seventh embodiment will be described with reference to FIG. In the reactor containment facility 20f, the upper pool 24 is made of steel,
It is installed above the dry well 23. Therefore, it is effective in shortening the construction period. Also.

The communication pipe 33f is connected through the outside of the dry well 23.

FIG. 8 is a longitudinal sectional view showing the eighth embodiment.

In the reactor containment facility 20g, the upper pool 24g is made of steel, and the drywell 23g is made of drywell 2.
The upper surface 38 is shaped like a smaller truncated cone than the bottom surface 40 of 3g. Therefore, since the dry well 23g becomes smaller, the capacity of the pressure suppression chamber 29 can be increased.

FIG. 9 is a longitudinal sectional view showing the ninth embodiment.

In the reactor containment facility 20h, the upper pool 24h is made of steel, and the outer walls of the dry well 23h and pressure suppression chamber 29h are made of steel, and the outside is surrounded by a biological shielding wall 4I that is a part of the reactor building for shielding. It is something.

Although the steel upper pool shown in the seventh to ninth embodiments is annular, the shape is not limited to this, and various types such as horizontal tanks, vertical tanks, and split tanks are also available. Available for use.

The present invention is not limited to the embodiments described above, and the dry well, pressure suppression chamber, and upper pool can be realized with various shapes and materials, and it is also possible to configure each embodiment by combining them.

〔Effect of the invention〕

According to the present invention, it has a stable structure, and also has good workability.
It is possible to provide a nuclear reactor containment facility with excellent reliability.

[Brief explanation of the drawing]

1 to 9 are longitudinal cross-sectional views showing first to ninth embodiments of the reactor containment facility according to the present invention, and FIG. 10 is a longitudinal cross-sectional view showing a conventional reactor containment vessel. 20, 20a, 20b, 20c, 20d
, 20e, 20f, 20g, 20h・
... Reactor containment facility 21 ... Core 22 ... Reactor pressure vessel 23, 23h ... Dry well 24, 24e, 24f, 24g, 24h - Upper pool 28 ... Emergency core cooling system piping substitute Person Patent Attorney Nori Ken Chika Yudo Ken Daishimaru

Claims (3)

[Claims] (1) A reactor pressure vessel that houses the reactor core, a dry well that surrounds the reactor pressure vessel, and a dry well that is located outside the dry well and at a higher position than the reactor core, with water stored in the lower part and a space in the upper part. an upper pool having an upper pool, emergency core cooling system piping connecting a lower part of the upper pool to the reactor pressure vessel, and a pressure suppression chamber disposed below the dry well, storing water in the lower part and having a space in the upper part. A nuclear reactor comprising: a vent pipe that connects a lower part of the pressure suppression chamber to the dry well; and a communication pipe that connects a space of the pressure suppression chamber and a space of the upper pool. Storage facility. (2) The nuclear reactor containment facility according to claim 1, wherein the end opening of the vent pipe on the dry well side is set at a position higher than the flood level of the dry well at the time of an accident. (3) The nuclear reactor containment facility according to claim 1, further comprising a dry well spray having one end connected to the lower part of the upper pool and the other end connected to the upper part of the dry well.