JPH02129590A - Nuclear reactor storage containment - Google Patents

Abstract

PURPOSE:To eliminate top heavy structure by providing a back flow preventing mechanism to the outlet of a vent pipe and also providing communication pipes between the cooling water in a dry well and a pressure suppression chamber, and the space part of an upper pool. CONSTITUTION:The space part of the pressure suppression chamber 4 is an airtight space, and the back flow preventing mechanism 11 is provided to the outlet of the vent pipe 5. Further, the space part of the dry well 3 and the space part of the supper pool 8, and the underwater part of the pressure suppression chamber 6 and the space part of the pool 8 are communicated by the communication pipe 12 and 2nd communication pipe 13. If a piping breakage accident occurs in the dry well 3, uncondensed gas discharged from the dry well 3 to the suppression chamber 4 through the communication pipe 12, the spaced part of the pool 8, and the communication pipe 13 produces a pressurized state in the space part of the suppression chamber 4. However, as the upper pool water 9 is injected into the nuclear reactor pressure containment 2 from the pool 8, the cooling water flows out of the piping breaking opening into the dry well 3 and vapor filling the dry well 3 is condensed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a pressure-suppressed reactor containment vessel for a nuclear power plant.

(Prior art) The reactor containment vessel has a dry well that houses the reactor pressure vessel that houses the reactor core containing fuel, etc., and a hypothetical accident in which the piping that connects to the reactor pressure vessel inside this dry well ruptures. , while reducing the pressure inside the reactor containment vessel,
It consists of a pressure suppression chamber that houses water, which acts as a heat sink to absorb the decay heat of the reactor core.

In the event of a hypothetical rupture of the piping connected to the reactor pressure vessel in the dry well, core cooling water would overflow from the reactor pressure vessel, which would eventually lead to core damage. To prevent this, emergency core cooling system equipment is provided that injects cooling water into the reactor pressure vessel using a pump from a pressure suppression chamber containing a large amount of water and a separate water source.

Recently, a simple structure that removes dynamic equipment such as pumps from the emergency core cooling system equipment and injects water from the water source above the core into the reactor pressure vessel using gravity has been attracting attention, as shown in Figure 2. The concept of a nuclear reactor containment vessel equipped with a simple emergency core cooling system facility as shown in 2007 has been disclosed.

In FIG. 2, a pressure suppression chamber 4 is provided in the lower part of a dry well 3 containing a reactor pressure vessel 2 having a reactor core 1, and in the event of a pipe rupture accident, pressure is suppressed from the dry well 3 through a vent pipe 5. A pressure suppression chamber pool water 6 is provided as a heat sink for condensing steam released into the chamber 4.

In addition, the upper pool 8 above the reactor core 1 is connected to the dry well 3.
The upper pool 8 has an upper pool water 9 that serves as a water source for the emergency core cooling system. The upper pool water 9 can be injected into the reactor pressure vessel 2 by gravity through the emergency core cooling system piping 7.

The space of the pressure suppression chamber 4 and the space of the upper pool 8 are connected by a communication pipe 10. dry well 3
In the event of a pipe rupture accident within the dry well 3 to pressure suppression chamber 4
The pressure in the space of the pressure suppression chamber 4 due to the non-condensable gas released during the operation is transmitted to the upper pool 8, and the upper pool water 9 as an emergency core cooling system is injected into the reactor pressure vessel 2. It is designed to play the role of driving pressure.

(Problem to be Solved by the Invention) By the way, the upper pool water 9 is used as an emergency core cooling system to inject water into the reactor pressure vessel 2 through the emergency core cooling system piping 7, and the amount of water is It is necessary to cover the entire amount of water that overflows into the dry well 3, and a large amount of water is required. Furthermore, water in the dry well 3 that has exceeded the top of the vent pipe 5 overflows into the pressure suppression chamber 4 . Therefore, because the reactor containment vessel has a large amount of water in its upper part, it has a top-heavy structure, and the seismic load due to its own weight or acceleration acting on the upper part during an earthquake is large, and pressure and heat are added in the event of an accident. Therefore, the reactor containment vessel legs must have a solid structure. For the reactor building that will be combined with this, a top-heavy structure is also disadvantageous in terms of stability in the event of an earthquake, and requires a wide foundation.

The present invention has been made to solve the above problems, and provides a reactor containment vessel that eliminates the top-heavy structure, further improves structural soundness, and is also excellent in economic efficiency.

[Structure of the Invention] (Means for Solving the Problems) The reactor containment vessel of the present invention includes a dry well containing a reactor pressure vessel having a reactor core and a coolant therein, and a heat sink surrounding the dry well. a pressure suppression chamber having cooling water, and an upper pool having cooling water as an emergency core cooling system arranged around the dry well above the reactor core, and a pipe communicating between the upper pool and the reactor pressure vessel. In the reactor containment vessel having a passageway, the pressure suppression chamber space is an airtight space, a backflow prevention mechanism is provided at the outlet of the vent pipe that communicates the cooling water of the drywell and the pressure suppression chamber, and the drywell and the upper pool are provided with a backflow prevention mechanism. The present invention is characterized in that first and second communication pipes are provided which communicate between the cooling water of the pressure suppression chamber and the space of the upper pool.

(Function) In the event of a pipe rupture accident in the dry well, non-condensable gas is released from the dry well into the pressure suppression chamber through the vent pipe, the first connecting pipe, the upper pool space, and the second connecting pipe. As a result, the space in the pressure suppression chamber becomes pressurized. As the upper pool water is injected into the reactor pressure vessel from the upper pool, cooling water flows into the dry well from the piping break, and the steam filling the dry well is condensed. As a result, an excessive pressure difference generated between the dry well and the pressure suppression chamber is suppressed.

(Example) An example of a reactor containment vessel of the present invention will be described with reference to FIG.

In FIG. 1, a pressure suppression chamber 4 is provided below or around a dry well 3. This pressure suppression chamber 4 is used as a heat sink to condense steam released from the dry well 3 into the pressure suppression chamber 4 in the event of a pipe rupture accident, and a pressure suppression chamber for the amount of water that overflows into the dry well 3 from the pipe rupture port. It has pool water 6. Further, an upper pool 8 is provided above or around the dry well 3 above the core 1 . The upper pool 8 has an amount of upper pool water 9 that is sufficient to serve as cooling water to be injected into the reactor pressure vessel 2 as an emergency core cooling system. The upper pool water 9 can be injected into the reactor pressure vessel 2 through the emergency core cooling system piping 7.

Here, the space of the pressure suppression chamber 4 is made an airtight space, and a backflow prevention mechanism 11 is provided at the outlet of the vent pipe 5, and between the space of the dry well 3 and the space of the upper pool 8,
The underwater part of the pressure suppression chamber pool water 6 and the space part of the upper pool 8 are connected by a first communication pipe 12 and a second communication pipe, respectively.
They are connected by a connecting pipe 13. In the event of a pipe rupture accident in the dry well 3, non-containing gas is discharged from the dry well 3 into the pressure suppression chamber 4 through the vent pipe 5 and the first connecting pipe 12 → the space of the upper pool 8 → the second connecting pipe 13. The space of the pressure suppression chamber 4 is pressurized by the WI compressible gas. However, as the upper pool water 9 is injected into the reactor pressure vessel 2 from the upper pool 8, cooling water flows out from the piping break into the dry well 3.
The steam filling inside is condensed. As a result, the pressure in the space of the pressure suppression chamber 4 becomes higher than the pressure in the dry well 3, that is, the pressure in the space of the upper pool 8, and the pressure suppression chamber pool water 6 passes through the second communication pipe 13 to the upper pool. 8 and becomes the water source for the emergency core cooling system equipment, and the pressure suppression chamber pool water 6 decreases, causing the pressure in the pressure suppression chamber 4 to drop, resulting in an excess pressure occurring between the dry well 3 and the pressure suppression chamber 4. Suppress differential pressure.

[Effect of the invention] According to the present invention, there are the following effects.

■ The upper pool water 9 stores the minimum amount of water required to cool the reactor pressure vessel 2. The impact of the load on the substructure materials is alleviated, improving structural integrity and economic efficiency.

■ As the initial operating pressure of the upper pool water 9, (static head)
10 (dry well pressure) is given, improving the health of Toyono as an emergency core cooling system facility.

■ After a pipe breakage accident in the dry well 3, the upper pool water 9 that leaked into the dry well 3 from the pipe break is returned to the pressure suppression chamber 5 through the vent pipe 5, and the pressure in the pressure suppression chamber 4 due to decay heat is reduced. As it rises, it is pushed up again into the pool 8, improving the functionality of the emergency core cooling system equipment.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view showing an embodiment of the reactor containment vessel according to the present invention, and FIG. 2 is a longitudinal cross-sectional view showing a conventional reactor containment vessel. 1...Reactor core 2...Reactor pressure vessel 3...Dry well 4...Suppression chamber 5...Vent pipe 6...Suppression chamber pool water 7...Emergency core cooling system Piping 8... Upper pool 9... Upper pool water 10... Communication pipe 11... Backflow prevention mechanism 12... First communication pipe 13... Second communication pipe (8733) agent Patent attorney Yoshiaki Inomata (baka)
1 person) Figure Figure

Claims (1)

[Claims] (1) A dry well containing a reactor pressure vessel with a reactor core and coolant inside, a pressure suppression chamber having cooling water as a heat sink around this dry well, and a space around the dry well above the core. In a reactor containment vessel having an upper pool having cooling water as an emergency core cooling system and having a pipe line communicating between the upper pool and the reactor pressure vessel, the pressure suppression chamber space is an airtight space, A backflow prevention mechanism is provided at the outlet of the vent pipe that communicates the cooling water of the pressure suppression chamber with the dry well, and between the dry well and the space of the upper pool and between the cooling water of the pressure suppression chamber and the space of the upper pool. A nuclear reactor containment vessel characterized by having first and second communication pipes communicating therebetween.