JPH08211181A - Reactor containment cooling device - Google Patents

Abstract

PURPOSE: To provide a reactor containment cooling device preventing the lowering of condensation heat transfer function in a heat exchanger and suppressing pressurization in the reactor containment by increasing the storage capacity of non-condensible gas in a non-condensible gas vent pipe with a low pressure vessel. CONSTITUTION: A reactor containment cooling device sucks steam and non- condensible gas contained in a reactor containment 2 and cools and condenses the steam with a gravity feed type core cooling system pool 6 and also exhaust the non-condensible gas through a non-condensible gas vent pipe 18 to a suppression pool 17. To the non-condensible gas vent pipe 18, a low pressure vessel 23 is connected by way of a switch valve 22.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to cooling of a nuclear reactor containment vessel in the event of loss of coolant in a nuclear reactor, and more particularly, to the decay heat of the nuclear reactor to the outside of the nuclear reactor containment vessel in a gravity drop type core cooling system. The present invention relates to a cooling device for a containment vessel that cools by removing heat.

[0002]

2. Description of the Related Art In a nuclear power plant, an emergency core cooling system that cools the core promptly is provided as an engineering safety facility in anticipation of a coolant loss accident, and multiple nuclear reactors are installed. Covered by container.

Further, the reactor containment vessel is provided with a cooling device for the reactor containment vessel for removing decay heat generated from the core for a long period of time after the accident occurs to the outside of the reactor containment vessel. .

A conventional reactor containment vessel cooling device has been to start a pump to send cooling water when an accident occurs, but recently, a natural phenomenon without using a rotating device such as a pump or the like. Is being used to develop a cooling device aiming to further improve safety and reliability.

This is called a static containment vessel cooling system, and the longitudinal sectional view of FIG. 4 shows a cooling system for a reactor containment vessel, which mainly shows piping paths in a heat exchanger. A reactor pressure vessel 4 accommodating a core 3 is stored in a reactor containment vessel 2 constructed in a reactor building 1, and a main steam pipe 5 is connected to the reactor pressure vessel 4. The main steam is sent to a turbine (not shown).

At the upper part of the reactor containment vessel 2, there is provided a gravity drop type core cooling system pool 6 for feeding cooling water to the reactor pressure vessel 4 after depressurization by a gravity head difference. The liquid level of the gravity-falling type core cooling system pool 6 is at the same pressure as the reactor containment vessel 2, and the gravity-falling type core cooling system pool 6 is cooled by a cooling water pipe 7 to form the reactor pressure vessel 4. Connected with.

A cooling water pool 8 is provided outside the reactor containment vessel 2 at a position higher than the gravity drop core cooling system pool 6, and a heat exchanger 9 is installed in the pool water of the cooling water pool 8. Has been done.

This heat exchanger 9 is composed of a group of vertical heat transfer tubes 10 immersed in water. A steam chamber 11 is provided above the heat transfer tubes 10 and a water chamber 12 is provided below the heat transfer tubes 10. In addition, the steam chamber 11 is connected to a steam supply pipe 14 that opens to the dry well 13 in the upper part of the reactor containment vessel 2.

In the water chamber 12 below the heat exchanger 9, a condensed water return pipe 15 opening into the gravity-falling core cooling system pool 6 and a suppression pool in the pressure suppression chamber 16 therebelow. A non-condensable gas vent pipe 18 connected to 17 is provided.

The condensed water return pipe 15 is provided with an inlet from the bottom of the water chamber 12, and the noncondensable gas vent pipe 18 is provided with an inlet slightly above the bottom. The operation of this static containment cooling system includes, for example, steam flowing out into the reactor containment vessel 2 and the pressure inside the reactor pressure vessel 4 rising abnormally.
As a result, a pressure reducing valve (not shown) opens or the main steam pipe 5
When is broken, the coolant in the reactor pressure vessel 4 is lost.

In this case, the pressure of the reactor pressure vessel 4 is lowered, and the cooling water 6a stored in the gravity drop type core cooling system pool 6 passes through the cooling water pipe 7 and the reactor pressure vessel 4
Supplied to

As a result, the core 3 is kept submerged by the cooling water 6a, but the pressure in the reactor pressure vessel 4 continues to rise. For further long-term cooling, the core 3 in the reactor pressure vessel 4 continues to generate decay heat, so if left without further cooling means, the pressure in the reactor containment vessel 2 will be reduced. It rises and exceeds the design pressure.

Therefore, by using the heat exchanger 9 in the cooling water pool 8, the steam in the reactor containment vessel 2 is supplied to the steam supply pipe 14
Through the heat transfer tube 10 of the heat exchanger 9 and is cooled and condensed by the surrounding pool water to suppress an increase in pressure.

This is the cooling system for the reactor containment vessel. This static containment cooling system performs the cooling phenomenon by utilizing a natural phenomenon called condensation. In this cooling system, the non-condensable property which is enclosed in the reactor containment vessel 2 for the purpose of fire prevention and the like. Heat transfer tube with gas and steam at the same time 10
Is sucked in.

This non-condensable gas is the heat transfer tube 10 of the heat exchanger 9.
When a non-condensable gas concentration boundary layer is formed in the vicinity of the heat transfer surface by flowing into the group, this becomes thermal resistance and reduces the condensing performance of the heat exchanger 9.

That is, when the pressure of the dry well 13 in the atomic storage container 2 rises, the mixture of vapor and non-condensable gas naturally flows through the vapor supply pipe 14 to the heat exchanger 9
Is sucked into the steam chamber 11 above.

Steam flows from the steam chamber 11 to the heat transfer tube 10 of the heat exchanger 9.
And is cooled by the pool water of the cooling water pool 8 during that time, most of it condenses into water, and the condensed water enters the water chamber 12 of the heat exchanger 9 and returns to the condensed water by gravity. It flows down through the pipe 15 into the gravity-falling core cooling system pool 6.

Condensed water that has flowed down into the gravity drop type core cooling system pool 6 together with the cooling water 6a that was initially stored is
This also flows through the cooling water pipe 7 due to the head differential pressure and is supplied to the reactor pressure vessel 4.

On the other hand, the non-condensable gas that does not condense in the heat exchanger 9 is discharged to the suppression pool 17 through the non-condensable gas vent pipe 18. At this time, the non-condensable gas is
The pressure suppression vent pipe 19 and the non-condensable gas vent pipe 18 are discharged due to the pressure difference due to the depth of submersion in the suppression pool 17.

The temperature of the cooling pool water in the cooling water pool 8 gradually rises due to the release of latent heat from the heat exchanger 9 and eventually starts to boil, but the steam generated at that time is released into the atmosphere. It is released and the water level decreases.

In the conventional static containment cooling system, the cooling water 6a in the gravity drop type core cooling system pool 6 is gradually reduced by supplying the cooling water to the reactor pressure vessel 4, and finally the liquid level is cooled. Since it reaches the nozzle height of the water pipe 7,
The flow rate of the cooling water flowing into the reactor pressure vessel 4 from the gravity drop type core cooling system pool 6 sharply decreases.

Since this cooling water is subcooled water, while this cooling water is flowing into the reactor pressure vessel 4, a part of the decay heat generated in the reactor core 3 has a heat quantity that makes the subcooled water saturated water. Although consumed, when the supply of cooling water is stopped, the flow rate of steam generated in the reactor pressure vessel 4 increases rapidly, and the pressures in the reactor pressure vessel 4 and the reactor containment vessel 2 rise rapidly.

Therefore, along with this, the reactor containment vessel 2
The flow rate of steam flowing into the steam chamber 11 of the heat exchanger 9 also rapidly increases, and the whole amount of the steam flowing into the heat transfer tube 10 cannot be condensed, and a large amount of uncondensed steam partially passes through the noncondensable gas vent tube 18. Is discharged to the suppression pool 17.

After that, when the amount of condensation in the heat transfer tube 10 recovers so as to exceed the amount of inflow steam, the pressure in the reactor containment vessel 2 turns to a reduced pressure, and the pressure in the water chamber 12 of the heat exchanger 9 gradually decreases. .

When the pressure in the water chamber 12 below the heat exchanger 9 becomes lower than the pressure corresponding to the depth (called sub-magence) in which the non-condensable gas vent pipe 18 is submerged in the suppression pool 17, the non-condensable gas vent is provided. The flow of the non-condensable gas discharged through the pipe 18 into the suppression pool 17 is stopped.

[0026]

[Problems to be Solved by the Invention] Suppression pool
When the discharge of the non-condensable gas into the interior of the non-condensable gas 17 is stopped, the non-condensable vapor is accumulated in the non-condensable gas vent pipe 18 in the vapor state together with a large amount of the non-condensable gas.

Further, although the flow rate of the non-condensable gas from the reactor containment vessel 2 to the heat exchanger 9 is still small, the non-condensable gas is stored in the heat transfer pipe 10 of the heat exchanger 9. Are accumulated again and the condensation heat transfer in the heat transfer tube 10 is deteriorated, which reduces the amount of vapor condensation and causes the pressure inside the reactor containment vessel 2 to rise again.

In the characteristic diagram of FIG. 5, the dry well pressure in the reactor containment vessel 2 and the pressure in the pressure suppression chamber 16 at the time of the main steam pipe breakage accident are shown by curves 20 and 21, respectively. Both pressures are temporarily reduced by the pool water from the cooling system pool 6 after the occurrence of the accident, but then gradually rise.

The object of the present invention is to increase the storage capacity of the non-condensable gas in the non-condensable gas vent pipe by means of the low-pressure container, thereby preventing the condensation heat transfer function of the heat exchanger from deteriorating. An object of the present invention is to provide a reactor containment vessel cooling device that suppresses an increase in temperature and pressure of the containment vessel.

[0030]

In order to achieve the above object, a cooling device for a reactor containment vessel according to the invention of claim 1 is provided with a gravity drop type core cooling system pool and is included in the reactor containment vessel. In the cooling device that sucks the vapor and the non-condensable gas into the heat exchanger to cool and condense the vapor and discharge the non-condensable gas to the suppression pool through the non-condensable gas vent pipe, It is characterized in that a low-pressure container is connected via an on-off valve.

A cooling device for a reactor containment vessel according to a second aspect of the present invention is characterized in that a low-pressure vessel connected to a non-condensable gas vent pipe is installed in a dry well of the reactor containment vessel.

A cooling device for a reactor containment vessel according to a third aspect of the present invention is characterized in that a low pressure vessel connected to a non-condensable gas vent pipe is installed in a pressure suppression chamber of the reactor containment vessel.

According to a fourth aspect of the present invention, there is provided an apparatus for cooling a reactor containment vessel, wherein an on-off valve in which a low pressure vessel is connected to a non-condensable gas vent pipe is provided with a pressure suppression chamber pressure which is constant for a predetermined time after a loss of coolant accident occurs. It is characterized by opening when it becomes.

According to a fifth aspect of the present invention, there is provided a cooling device for a reactor containment vessel, wherein an opening / closing valve connecting the low pressure vessel to a noncondensable gas vent pipe is opened at a preset time after a loss of coolant accident. To do.

According to a sixth aspect of the present invention, there is provided an apparatus for cooling a reactor containment vessel, wherein an on-off valve connecting a low pressure vessel to a non-condensable gas vent pipe is used, and the cooling water in the gravity drop core cooling system pool is emptied. It is characterized by opening when you open it.

According to a seventh aspect of the present invention, there is provided a cooling device for a reactor containment vessel, wherein the volume of the low pressure vessel connected to the non-condensable gas vent pipe corresponds to the volume of the heat transfer pipe in the heat exchanger. To do. A cooling device for a reactor containment vessel according to an eighth aspect of the present invention is characterized in that a low pressure vessel connected to a non-condensable gas vent pipe is previously set to a negative pressure.

[0037]

According to the first aspect of the present invention, of the steam and the noncondensable gas contained in the reactor containment vessel at the time of the loss of coolant, the steam is cooled and condensed in the heat exchanger. However, although the non-condensable gas is initially discharged from the heat exchanger through the non-condensable gas vent pipe to the suppression pool,
It is stored in the non-condensable gas vent pipe and the heat exchanger to hinder the heat exchange in the heat exchanger and the cooling and condensing function of steam, and the temperature and pressure of the reactor containment vessel rise.

However, when the non-condensable gas is stored in the non-condensable gas vent pipe, if the opening / closing valve is opened, the non-condensable gas is sucked into the low-pressure container, and the non-condensable gas stored in the heat exchanger is removed. Since the heat is discharged, the heat exchange function of the heat exchanger is favorably maintained, and the temperature and pressure increase in the reactor containment vessel can be suppressed.

According to the second aspect of the present invention, maintenance is facilitated by installing the low-pressure vessel for sucking the non-condensable gas in the dry well of the reactor containment vessel. By covering the low-pressure container with a heat insulating material, it is possible to secure an effective capacity of the low-pressure container without being affected by an increase in ambient temperature even when a coolant loss accident occurs.

According to the third aspect of the present invention, since the low-pressure vessel for sucking the non-condensable gas is installed in the pressure suppression chamber of the reactor containment vessel, the ambient temperature does not rise even when a loss of coolant accident occurs, The effective capacity of the low-pressure container can be easily ensured.

According to the fourth aspect of the present invention, when the coolant loss accident occurs, the fact that the non-condensable gas is stored in the non-condensable gas vent pipe is detected by the pressure suppression chamber pressure being kept constant for a predetermined time. Then, the on-off valve is opened to suck the non-condensable gas into the low pressure container.

According to the fifth aspect of the present invention, when a loss-of-coolant accident occurs, the fact that the non-condensable gas is stored in the non-condensable gas vent pipe is set in advance according to the elapsed time from the occurrence of the accident. After the set time, the on-off valve is opened to suck the non-condensable gas into the low pressure container.

In the sixth aspect of the present invention, when the non-condensable gas is stored in the non-condensable gas vent pipe in the occurrence of the loss of coolant accident, the cooling water in the gravity-falling core cooling system pool becomes empty. Since it almost coincides with the time, the time when the cooling water in the gravity drop type core cooling system pool is emptied is detected, the on-off valve is opened, and the non-condensable gas is sucked into the low pressure vessel.

According to a seventh aspect of the present invention, the volume of the low-pressure container connected to the noncondensable gas vent pipe is formed to correspond to the volume of the heat transfer pipe in the heat exchanger, so that the noncondensable gas is stored in the heat transfer pipe. Suppress.

In the eighth aspect of the present invention, since the low-pressure container for sucking the non-condensable gas is set to a negative pressure in advance, the available effective capacity thereof increases, so that the non-condensable gas can be sucked effectively. If the volumes are the same, the low-pressure container can be downsized.

[0046]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. It should be noted that the same components as those of the above-described conventional technique are denoted by the same reference numerals and detailed description thereof will be omitted. In the first embodiment, as shown in the cross-sectional view of the main part of the reactor pressure vessel of FIG. 1 omitted, after decompression, the upper part of the reactor containment vessel 2 (not shown) built in the reactor building 1 Reactor pressure vessel 4
A gravity-falling-type core cooling system pool 6 for feeding the cooling water 6a by a gravity head difference is provided in the.

The gravity drop type core cooling system pool 6
The liquid surface of the reactor is made to have the same pressure as the reactor containment vessel 2, and the gravity drop type core cooling system pool 6 is connected to the reactor pressure vessel 4 by a cooling water pipe 7.

Further, a cooling water pool 8 is provided outside the reactor containment vessel 2 at a position higher than the gravity drop core cooling system pool 6, and a heat exchanger 9 is installed in the pool water of the cooling water pool 8. Has been done.

This heat exchanger 9 is composed of a group of vertical heat transfer tubes 10 immersed in water. A steam chamber 11 is provided above the heat transfer tubes 10 and a water chamber 12 is provided below the heat transfer tubes 10. In addition, the steam chamber 11 is connected to a steam supply pipe 14 that opens to the dry well 13 in the upper part of the reactor containment vessel 2.

In the water chamber 12 below the heat exchanger 9, a condensed water return pipe 15 that opens into the gravity-falling core cooling system pool 6 and a suppression pool inside the pressure suppression chamber 16 are provided. A non-condensable gas vent pipe 18 connected to 17 is connected.

The condensed water return pipe 15 is provided with a lead-in port from the bottom of the water chamber 12, the non-condensable gas vent pipe 18 is provided slightly above the bottom, and the non-condensable gas vent pipe 18 is further provided with: Open / close valve 22 installed in drywell 13
A low-pressure vessel 23 having the same pressure as the reactor containment vessel during normal operation is connected via the.

Next, the operation of the above configuration will be described. A reactor coolant loss accident occurred, the pressure in the drywell 13 of the reactor containment vessel 2 increased, and the steam supply pipe
The inflow amount of steam and noncondensable gas from 14 to the heat exchanger 9 increases, and the heat exchanger 9 and the inside of the noncondensable gas vent pipe 18 increase.
When non-condensable gas accumulates in the heat transfer tube 10 of
The condensing heat transfer at the point becomes worse, and as a result, the amount of vapor condensing decreases and the temperature in the reactor containment vessel 2 rises, so that the pressure further rises.

At this time, by a pressure detector (not shown),
When the on-off valve 22 is opened upon detecting a pressure increase in the non-condensable gas vent pipe 18 or the pressure suppression chamber 16, the heat transfer pipe of the heat exchanger 9 is opened.
A large amount of non-condensable gas accumulated in the non-condensable gas vent pipe 18 together with 10 is sucked into the low-pressure container 23 via the opening / closing valve 22.

As a result, the pressure in the heat transfer tube 10 and the noncondensable gas vent tube 18 of the heat exchanger 9 decreases, the noncondensable gas in the heat transfer tube 10 is discharged, and the noncondensable gas is accumulated. Since this is prevented, the heat exchange and vapor condensing performance in the heat exchanger 9 can be favorably maintained.

Further, since the on-off valve 22 and the low pressure container 23 are installed in the dry well 13, maintenance is easy. When the low-pressure container 23 is affected by the temperature in the dry well 13 that rises when an accident occurs and the temperature of the low-pressure container 23 rises, the internal pressure also rises and the pressure difference between the non-condensable gas vent pipe 18 decreases. Since the effective capacity for sucking the non-condensable gas decreases, it is preferable to enclose it in advance with a heat insulating material in order to avoid the influence of ambient temperature.

In the second embodiment, the on-off valve 22 and the low pressure container 23 are arranged in the pressure suppression chamber 16 as shown in the sectional view of the essential structure of FIG. According to this configuration, the temperature of the pressure suppression chamber 16 is lower than that of the dry well 13 at the time of the accident,
The low-pressure container 23 does not need to be covered with a heat insulating material. In addition, about the other effect | action, the thing similar to the said 1st Example is obtained.

As a third embodiment, in the above first and second embodiments, the timing for opening the on-off valve 22 and sucking the non-condensable gas in the non-condensable gas vent pipe 18 into the low pressure container 23 is cooling. When a material loss accident occurs, the pressure in the dry well 13 rises and vapor and non-condensable gas enter the heat exchanger 9, as shown by the curve 20 in the characteristic diagram of FIG.

When the steam is condensed in the heat exchanger 9, the pressure in the water chamber 12 becomes low, and the noncondensable gas starts to accumulate in the noncondensable gas vent pipe 18. At this time, the pressure in the pressure suppression chamber 16 changes almost in the same manner as the pressure in the dry well 13, as shown by the curve 21.

After that, the time change of the pressure in the pressure suppression chamber 16 becomes constant for a while at the time of arrow 24. Therefore, a pressure detector (not shown) is installed in the pressure suppression chamber 16, detects that there is no pressure change within a predetermined time, opens the on-off valve 22 at this point, and accumulates in the noncondensable gas vent pipe 18. The generated non-condensable gas is sucked into the low pressure container 23.

When the on-off valve 22 is opened and the non-condensable gas is sucked into the low pressure container 23, the pressure difference between the non-condensable gas vent pipe 18 and the low pressure container 23 disappears, but the non-condensable gas is stored. Since the capacity is increased, the noncondensable gas in the heat exchanger 9 easily flows to the noncondensable gas vent pipe 18 side.

The time and the number of times the open / close valve 22 is kept open depend on the pressure difference between the state in which the non-condensable gas is accumulated in the non-condensable vent pipe 18 and the pressure in the low-pressure container 23. You may perform it suitably.

In the fourth embodiment, as the timing for opening the on-off valve 22, the time point indicated by the arrow 24 in FIG. 3 is confirmed as the elapsed time from the occurrence of the accident by experiments or the like, and the preset time is set. When an accident occurs, the open / close valve 22 is controlled to be opened with a simple mechanism at an appropriate timing so that the noncondensable gas accumulated in the noncondensable gas vent pipe 18 can be sucked into the low-pressure container 23.

In the fifth embodiment, the time when the cooling water 6a in the gravity-falling type core cooling pool 6 is emptied and the time when the noncondensable gas is accumulated in the noncondensable gas vent pipe 18 are almost the same.

Therefore, when the gravity drop type core cooling pool water 6a is emptied, it is detected by a water level detector (not shown) and the on-off valve 22 arranged in the non-condensable gas vent pipe 18 is opened, The non-condensable gas accumulated in the condensable gas vent pipe 18 can be appropriately sucked into the low pressure container 23.

The sixth embodiment is to remove the non-condensable gas accumulated in the heat transfer tube 10 as much as possible in order to make the heat exchange function sufficiently in the heat exchanger 9. The volume of the container 23 may be equivalent to the volume of the heat transfer tube 10.

An example of the heat transfer tube 10 is one having an inner diameter of 0.05 m, a height of 1.8 m, and about 500 tubes per unit. Therefore, the volume of this heat transfer tube 10 is 0.05 ² × π
Since /4×1.8×500=1.6 (m ³ ), the storage capacity of the noncondensable gas can be doubled by installing the low-pressure container 23 having such a volume.

As a seventh embodiment, by preliminarily setting the low pressure container 23 to a negative pressure, the available effective capacity can be increased. At this time, the opening / closing valve 22 is opened a plurality of times for a short time to obtain the differential pressure between the noncondensable gas vent pipe 18 and the low-pressure container 23 each time.

Further, by effectively utilizing the effective capacity, a large amount of non-condensable gas can be sucked from the non-condensable gas vent pipe 18 to the low pressure container 23. Furthermore, if the low-pressure container 23 has the same volume, it is easy to make it compact.

[0069]

As described above, according to the present invention, the non-condensable gas that has flowed into the heat transfer tube of the heat exchanger is discharged well, and the steam condensing function in the heat exchanger is improved so that the reactor pressure vessel and the reactor containment are improved. Since it suppresses the rise of pressure as well as the temperature of the vessel, it has the effect of improving the safety and reliability of reactor operation.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of the essential parts of a cooling device for a reactor containment vessel according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of the essential parts of a cooling device for a reactor containment vessel according to a second embodiment of the present invention.

FIG. 3 is a pressure characteristic diagram of a dry well and a pressure suppression chamber at the time of a loss of coolant accident in one embodiment according to the present invention.

FIG. 4 is a sectional view showing the configuration of a conventional cooling device for a reactor containment vessel.

FIG. 5 is a pressure characteristic diagram of a dry well and a pressure suppression chamber at the time of a loss of coolant accident.

[Explanation of symbols]

1 ... Reactor building, 2 ... Reactor containment vessel, 3 ... Reactor core, 4 ...
Reactor pressure vessel, 5 ... Main steam piping, 6 ... Gravity drop type core cooling system pool, 6a ... Cooling water, 7 ... Cooling water piping, 8 ... Cooling water pool, 9 ... Heat exchanger, 10 ... Heat transfer tube, 11 … The steam room,
12 ... Water chamber, 13 ... Dry well, 14 ... Steam supply pipe, 15 ... Condensate return pipe, 16 ... Pressure suppression chamber, 17 ... Suppression pool, 18 ... Non-condensable gas vent pipe, 19 ... Pressure suppression vent pipe, 20 … Drywell pressure curve, 21… Pressure suppression chamber pressure curve, 22… Open / close valve, 23… Low pressure container, 24… Pressure suppression chamber pressure temporary certain point (arrow).

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location G21C 9/004 GDB 13/00 GDB

Claims (8)

[Claims] 1. A gravity-drop type core cooling system pool is provided, and steam and non-condensable gas contained in the reactor containment vessel are sucked into a heat exchanger to cool and condense the steam and to prevent non-condensable gas from being condensed. In a cooling device for discharging to a suppression pool via a condensable gas vent pipe, a low-pressure container via an open / close valve is connected to the non-condensable gas vent pipe. 2. The cooling device for a reactor containment vessel according to claim 1, wherein the low pressure container connected to the non-condensable gas vent pipe is installed in a dry well of the reactor containment vessel. 3. The cooling device for a reactor containment vessel according to claim 1, wherein the low-pressure container connected to the non-condensable gas vent pipe is installed in a pressure suppression chamber of the reactor containment vessel. 4. The on-off valve, which connects the low-pressure container to the non-condensable gas vent pipe, opens when the pressure in the pressure suppression chamber becomes constant for a predetermined time after the occurrence of a loss of coolant accident. The cooling device for the reactor containment vessel according to claim 3. 5. The reactor containment vessel according to claim 1, wherein the on-off valve connecting the low-pressure vessel to the non-condensable gas vent pipe is opened at a preset time after a loss of coolant accident. Cooling system. 6. The on-off valve, which connects the low-pressure vessel to a non-condensable gas vent pipe, is opened when the cooling water in the gravity-drop core cooling system pool is emptied. Item 3. A cooling device for a reactor containment vessel according to Item 3. 7. The reactor containment vessel according to claim 1, wherein the volume of the low-pressure vessel connected to the non-condensable gas vent pipe corresponds to the volume of the heat transfer tube in the heat exchanger. Cooling system. 8. The low-pressure container connected to the non-condensable gas vent pipe is set to a negative pressure in advance.
The cooling device for the reactor containment vessel according to claim 3.