JPH04351996A - Reactor container - Google Patents

Abstract

PURPOSE:To lower the volume of water source for emergency to lower the load of a container at the time of an earthquake and improve the stability of a plant building by installing a flow preventing means for cooling water which flows at the time of an accident in a vent pipe. CONSTITUTION:In the case that a pipeline 6 is ruptured and water pours itself into a pressure container 3 by a water pouring system 10 from a water source 11 for emergency, since the upper end part of a vent pipe 9 is extruded from a diaphragm floor 15, the cooling water 14 overflowing out of the ruptured part of the pipeline 6 does not flow in the pressure suppressing chamber 8. Consequently, it is not necessary to store water in the amount equivalent to the cooling water 13 of the chamber 8 in the water source 11 and thus the volume of the water source 11 can be lessened. a nuclear reactor container-lower part dry well communicating pipeline 16 which is communicated with a lower part dry well 5 and has a valve 8 is installed in the container 3. As a result, the cooling water 12 flowing in and stored in the dry well 5 flows to the container 3 through the valve 8 opened by an accident signal and the pipeline 16 and the water levels of the container 3 and the dry well 5 are balanced and the nuclear core 2 is submerged.

Description

[Detailed description of the invention]

[Purpose of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nuclear reactor containment vessel, and more particularly to a nuclear reactor containment vessel equipped with an emergency water injection system having a separate emergency water source.

0002

2. Description of the Related Art FIG. 4 is a schematic longitudinal cross-sectional view showing the general structure of a boiling water nuclear reactor. In this figure, a reactor pressure vessel (hereinafter referred to as RPV) 3 containing a reactor core 2 is arranged within a reactor containment vessel (hereinafter referred to as PCV) 1. PCV1 is the upper dry well (hereinafter referred to as U/D) 4
and a lower dry well (hereinafter referred to as L/D) 5, and piping 6 connected to the RPV 3 within these dry wells.
It has a pressure suppression chamber (hereinafter referred to as S/P) 8 that reduces the pressure inside the PCV 1 when the PCV 1 ruptures. This S/
P8 stores cooling water 7, and communicates the gas phase region with the inside of the dry well through a vent pipe 9.

[0003] Furthermore, in the event of a rupture accident in the pipe 6 connected to the RPV 3 in the dry well, the coolant for the core 2 will overflow from the RPV 3, and if left as it is, the core 2 will overheat. In order to prevent this overheating, the PCV 1 is provided with a water injection system 10 for injecting a large amount of cooling water into the RPV 3 and an emergency water source 11 thereof.

In the boiling water reactor having the above configuration, when the pipe 6 breaks and water is injected from the emergency water injection system 10 into the RPV 3, a portion of the cooling water is absorbed into the pipe 6 as shown in FIG. 14. It flows out into PCV1 from the point and flows through the upper part of diaphragm lower (hereinafter referred to as D/F) 15 to L.
/ Flows into D5 and is stored here (cooling water 12 in the figure)
). Also, from the opening of the vent pipe 9 to the vent pipe 9
It also flows into the S/P8 (shown as cooling water 13 in the figure).

[0005] Furthermore, the reactor core 2 must be submerged in water for a long period of time after the accident to remove decay heat from the reactor core 2, but the emergency water source 11 not only has the amount of water necessary to inject into the RPV 3 and submerge the reactor core 2, but also Inside L/D5 and S/P
It must be possible to store a large amount of water to cover the cooling water 12, 13 flowing into and stored in the cooling water tank 8.

[0006]

[Problems to be Solved by the Invention] As mentioned above, in the conventional boiling water reactor, the emergency water source 11 of the emergency water injection system 10 is only the water that is injected into the RPV 3 and into the reactor core 2. It was necessary to have a large capacity to store water that flows into L/D5 and S/P8 and is not involved in cooling the reactor core 2 or flooding. Providing the large-capacity emergency water source 11 in the PCV1 in this way simply means that the PCV1
Not only would this be a design limitation, but it would also lead to a top-heavy state of PCV1, which would place a large earthquake load on the legs of PCV1, and could potentially impair the stability of the plant building during an earthquake.

[0007] The present invention was made based on the above circumstances, and suppresses the flow of cooling water injected into the RPV into the S/P for cooling the reactor core and flooding during an accident, thereby reducing the capacity of the emergency water source. The purpose is to provide a PCV that can [Structure of the invention]

[0008]

[Means for Solving the Problems] The reactor containment vessel of the present invention includes an upper dry well, a lower dry well, and a pressure suppression chamber that communicates with the gas phase region of the upper dry well via a vent pipe, and separate In the reactor pressure vessel containing the reactor core, which is equipped with a standalone emergency water source, and which surrounds the reactor pressure vessel housing the reactor core, means for preventing cooling water that has flowed from the reactor pressure vessel into the upper dry well in the event of an accident from flowing into the vent pipe. It is characterized by having the following.

[0009]

[Function] In the reactor containment vessel of the present invention having the above configuration, the upper end of the vent pipe is provided with a means for preventing the inflow of cooling water, so that the pressure of the cooling water overflowing from the broken part of the pipe is suppressed. It does not flow into the room, and there is no need to store the amount of water that flows into and is stored in the pressure suppression chamber in the separate emergency water source as in the conventional case, and the capacity of the emergency water source can be reduced. This solves the problems caused by conventional large capacity emergency water sources.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1, in which the same parts as in FIG. 4 are denoted by the same reference numerals, is a schematic longitudinal cross-sectional view of a main part of a first embodiment of the present invention. In this figure, the upper end of the vent pipe 9 protrudes from the upper wall of the S/P 8, that is, the D/F 15. Also, R
The PV3 is provided with an RPV-L/D communication pipe 16 having a valve 18 at an end between the L/D5 and the communication history L/D5.

As mentioned above, the upper end of the vent pipe 9 is connected to the D/F1
5 protrudes from the top surface, so the cooling water 14 overflowing from the broken part of the pipe 6 does not flow into the S/P8, and instead is sent to the emergency water source 11, which corresponds to the cooling water 13 in the S/P8 in Fig. 4. There is no need to store water, and the capacity of the emergency water source 11 can be reduced.

[0012] As a result, the conventional large-capacity emergency water source 1
The various problems caused by 1 can be solved. In addition, the cooling water 12 that has flowed into and stored in the L/D5 flows into the RPV6 via the valve 18 opened by the accident signal and the RPV-L/D communication pipe 16, and is connected to the RPV3 and the L/D5.
/ Balances the water level in D5 and contributes to flooding of core 2.

FIG. 2, in which the same parts as in FIGS. 1 and 4 are denoted by the same reference numerals, is a schematic vertical sectional view of the main part of a second embodiment of the present invention. In this figure, the vent pipe 9 is opened in the side wall of the S/P 8. Therefore, the cooling water 14 that has flowed down onto the upper surface of the D/F 15 does not flow into the vent pipe 9, and the same effect as in the first embodiment can be obtained.

FIG. 3, in which the same parts as those in the previous figures are given the same reference numerals, is a schematic longitudinal sectional view of the main part of a third embodiment of the present invention. In this figure, the vent pipe 9 is opened to the D/F 15 similarly to the conventional vent pipe shown in FIG. 4, and a cylindrical weir 17 is provided around the opening. Weir 17 above
Since this prevents the cooling water that has flowed down to the D/F 15 from flowing into the vent pipe 9, the same effects as in the previous embodiment can be obtained in this embodiment as well.

It should be noted that the present invention is not limited to the above embodiments. For example, the installation of the RPV-L/D communication piping 16 may be omitted. Furthermore, the shape and structure of the PCV are not limited to those illustrated.

[0016]

Effects of the Invention As is clear from the above, in the reactor containment vessel of the present invention, when emergency cooling water is injected into the reactor pressure vessel in the event of a pipe rupture accident, the reactor containment vessel Since the cooling water that flows into the reactor does not flow into the pressure suppression chamber, the emergency water source only needs to have a capacity that stores enough water to cool the core and contribute to flooding. Therefore, the weight of the emergency water source can be reduced and the top-heavy condition of the reactor containment vessel will not occur, so that excessive loads on the reactor containment vessel legs during an earthquake can be avoided. It is also possible to improve the stability of nuclear plant buildings.

[Brief explanation of drawings]

FIG. 1 is a schematic vertical cross-sectional view of the main parts of a first embodiment of the present invention.

FIG. 2 is a schematic vertical cross-sectional view of the main parts of a second embodiment of the present invention.

FIG. 3 is a schematic longitudinal cross-sectional view of the main parts of a third embodiment of the present invention.

FIG. 4 is a schematic vertical cross-sectional view showing the schematic configuration of a boiling water reactor.

[Explanation of symbols]

Claims (1)

[Claims] 1. An upper dry well, a lower dry well, a pressure suppression chamber communicating with the gas phase region of the upper dry well via a vent pipe, and a separate emergency water source,
In the reactor pressure vessel surrounding the reactor core containing the reactor core, the vent pipe is provided with means for preventing cooling water flowing out from the reactor pressure vessel into the upper dry well in the event of an accident. Reactor containment vessel.