JP2001083275A - Reactor containment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively suppress pressurization in a reactor containment even in the case of generation of a major accident accompanied by core damage. SOLUTION: A lower drywell 4 surrounded by nearly cylindrical pedestal 3 supporting the lower part of a reactor containment 2 is provided. The lower drywell 4 stores pool water for damaged core cooling during discharge of the damaged core in accidents from the reactor pressure vessel 2. A pressure suppression chamber 7 surrounding the pedestal and storing pressure suppression pool water 6 at the bottom is provided. Above it, an upper drywell 5 surrounding the pressure vessel 2 is provided. In the lower drywell 4, at least one lower drywell cooling unit 12A constituted so that the atmosphere in the lower drywell 4 and pool water for damaged core cooling are coolable is arranged.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a containment vessel for a nuclear power plant, and more particularly to a structural improvement for improving safety in the event of an accident.

[0002]

2. Description of the Related Art A conventional reactor containment vessel shown in FIG. 1 has a reactor pressure vessel 2 containing a reactor core 1 and a substantially cylindrical pedestal supporting a lower portion of the reactor pressure vessel 2.
3 is provided. The containment vessel includes a lower dry well 4 surrounded by the pedestal 3. The lower drywell 4 stores the damaged core cooling pool water when the damaged core is released from the reactor pressure vessel 2 due to a core damage accident.

A pressure suppression chamber 7 is provided around the pedestal 3. The suppression chamber 7 stores the suppression pool water 6 at the bottom. Further, an upper dry well 5 is provided above the pressure suppression chamber 7 so as to surround the reactor pressure vessel 2. The upper dry well 5 and the lower dry well 4 are communicated with each other by a communication hole 8. Each of the dry wells 4 and 5 and the suppression chamber 7 are connected by a main vent pipe 9 extending into the suppression pool water 6.

[0004] In the upper drywell 5, a plurality of drywell cooling units 12B are provided.
These drywell cooling units 12B include a heat exchanger 10 and a casing 11 that houses the heat exchanger 10. Among them, the heat exchanger 10 is configured to be able to cool gas passing outside the cooling coil by a cooling coil connected to a cooling water system.

In the upper dry well 5, a blower 13 and a duct 14 corresponding to each dry well cooling unit 12B are provided. And this blower 13
As a result, the casing 1 of the corresponding cooling unit 12B
While sucking the atmosphere of the upper dry well 5 into 1,
The gas cooled by the heat exchanger 10 is blown through the duct 14 to each of the dry wells 4 and 5. Thus, the atmosphere in each of the dry wells 4 and 5 during normal operation can be cooled to a specified state.

[0006] The pressure suppression pool water 6 is guided into the reactor containment vessel by the pump P, and the residual heat removal heat exchanger 16 is provided.
After the heat is removed from the spray header 17, a containment vessel cooling system for spraying and spray cooling from the spray header 17 is provided.

In such a reactor containment vessel, the LOCA in the reactor pressure vessel 2
When (Loss of Coolant Accident) occurs, a large amount of a mixture of high-temperature steam and water is discharged into each of the dry wells 4 and 5. In this case, a mixture of high-temperature steam and water is supplied to the suppression chamber 7 through the main vent pipe 9.
The water is guided into the pressure suppression pool water 6 in the inside, so that an increase in the internal pressure of the containment vessel is suppressed.

Further, the core 1 in the reactor pressure vessel 2 is sufficiently cooled by the multiple emergency core cooling systems, and generated in the core 1 by the containment vessel cooling systems P, 16 and 17. The decay heat is designed to be removed outside the containment vessel for a long time. In the unlikely event that core fuel is used, FP (Fission Products: fission products)
Even if is released, it is designed to maintain the integrity of the reactor containment vessel at a high level, suppress FP leakage to the environment to a very small amount, and ensure high safety of the reactor.

[0009] Furthermore, although it is an extremely rare event in terms of probability, a serious accident in which a plurality of safety equipment provided as described above fails and the reactor core 1 is damaged (melted) can be assumed. . Therefore, even in the case of such a serious accident, from the viewpoint of defense in depth, the water supply to the reactor pressure vessel 2 and each of the dry wells 4 and 5 is performed and spraying is performed by using a normal system equipment to replace the damaged core. It is designed so that the cooling and the condensing of the steam generated at that time suppress the rise in the temperature and pressure of the containment vessel.

As described above, the conventional containment vessel is
It is designed to maintain a high level of safety by making full use of existing service equipment in addition to emergency safety equipment.

[0011]

As described above, the reactor pressure vessel 2 is damaged by a serious accident such as core damage (melting).
If the damaged safety core is released to the outside and the original safety equipment does not recover quickly, use normal equipment to inject or spray cooling water introduced from an external water source into the reactor containment vessel. Then, the inside of the damaged core and each of the dry wells 4 and 5 are cooled.

However, if cooling water is continuously introduced from an external water source for a long period of time, a large amount of water is stored in the reactor containment vessel, thereby compressing the gas phase volume and conversely increasing the internal pressure of the reactor containment vessel. There is a possibility.

The present invention has been made in view of these problems, and even in the event of a serious accident such as damage to the reactor core, the internal pressure of the containment vessel is effectively suppressed from rising, and safety is improved. It is an object of the present invention to provide a reactor containment vessel capable of further improving the reactor containment.

[0014]

A first means is a reactor pressure vessel containing a reactor core, a substantially cylindrical pedestal supporting a lower portion of the reactor pressure vessel, and is surrounded by the pedestal. A lower drywell for storing the damaged core cooling pool water when the damaged core is released from the reactor pressure vessel, a pressure suppression chamber provided surrounding the pedestal and storing the pressure suppression pool water at the bottom, An upper dry well provided above the reactor and surrounding the reactor pressure vessel, and at least one unit provided in the lower dry well and configured to cool a fluid in the lower dry well. A reactor containment vessel comprising a lower drywell cooling unit.

According to the first means, when the damaged core is released from the reactor pressure vessel, the damaged core cooling pool water stored in the lower drywell is directly cooled by the lower drywell cooling unit. it can. This allows sufficient cooling of the reactor pressure vessel without introducing a large amount of cooling water from an external water source.

A second means is the first means, wherein the lower drywell cooling unit is disposed above a maximum deposition height of a melt deposited in the lower drywell when the damaged core is discharged. It is.

According to the second means, in the first means, it is possible to prevent the lower drywell cooling unit from being damaged by the melt deposited in the lower drywell when the damaged core is discharged.

The third means is the first or second means, wherein the lower drywell cooling unit houses a heat exchanger for cooling a fluid in the lower drywell and the heat exchanger. A casing, and at least two opposing surfaces of the casing are formed with openings for sucking the atmosphere in the lower drywell.

According to the third means, when the pool water for cooling the damaged core is cooled by the lower drywell cooling unit in the first or second means, the pool water is effectively introduced into the casing from the opening. To promote cooling of the damaged core cooling pool water by the heat exchanger in the casing.

The fourth means is a reactor pressure vessel containing a reactor core, a substantially cylindrical pedestal supporting a lower part of the reactor pressure vessel, and a pedestal which is surrounded by the pedestal and receives the pressure from the reactor pressure vessel. A lower drywell for storing pool water for cooling the damaged core when releasing the damaged core;
A pressure suppression chamber provided surrounding the pedestal and storing a suppression pool water at the bottom; an upper dry well located above the suppression chamber and provided surrounding the reactor pressure vessel; and At least one upper drywell cooling unit provided in the drywell and configured to be able to cool the atmosphere in the upper drywell, and from the inside of the upper drywell cooling unit to the pressure suppression pool water of the pressure suppression chamber. And a gas vent pipe communicating with the reactor vessel.

Here, when the atmosphere in the upper drywell is cooled by the upper drywell cooling unit, water vapor in the atmosphere is condensed. Thereby, the atmosphere in the upper drywell containing the non-condensable gas is sucked into the upper drywell cooling unit.

According to the fourth means, the non-condensable gas sucked into the upper drywell cooling unit can be discharged into the suppression pool water of the suppression chamber by the gas vent pipe. As a result, in the upper drywell cooling unit, deterioration of water vapor condensation due to accumulation of non-condensable gas can be avoided, and the heat removal effect can be enhanced.

Fifth means is the fourth means, further comprising a main vent pipe communicating from inside the upper drywell and the lower drywell to the water in the suppression pool in the suppression chamber. In the water
The gas vent pipe is open at a position higher than the main vent pipe.

According to the fifth means, in the fourth means, the non-condensable gas sucked into the upper drywell cooling unit can be efficiently discharged to the pressure suppression chamber through the gas vent pipe.

According to a sixth aspect, in the fourth or fifth aspect, the gas vent pipe is provided with a check valve for preventing a flow from the pressure suppression chamber side to the upper drywell cooling unit side. is there.

According to the sixth means, in the fourth or fifth means, it is possible to prevent the pressure suppression pool water from being sucked into the upper drywell cooling unit through the gas vent pipe.

A seventh means is the first or fourth means, wherein a cooling water system indirectly cooled by seawater is used as a cooling means in each drywell cooling unit; A cooling water system is provided to be switchable.

According to the seventh means, in the first or fourth means, even if the normal cooling water system becomes unusable for some reason, the cooling by each drywell cooling unit is ensured by the spare cooling water system. be able to.

[0029]

Next, an embodiment of the present invention will be described with reference to the drawings. 1 to 6 are views showing an embodiment of a containment vessel according to the present invention. In addition,
In the embodiment of the present invention shown in FIGS.
The same components as those of the conventional example shown in FIG.

[First Embodiment] First, a first embodiment of the present invention will be described with reference to FIGS.

<Structure> In FIG. 1, a reactor containment vessel according to the present embodiment comprises a reactor pressure vessel 2 having a reactor core 1 therein.
And a substantially cylindrical pedestal 3 that supports a lower portion of the reactor pressure vessel 2. The containment vessel has a lower drywell 4 surrounded by the pedestal 3. The lower drywell 4 stores the damaged core cooling pool water when the damaged core is released from the reactor pressure vessel 2 due to a core damage accident.

A pressure suppression chamber 7 is provided surrounding the pedestal 3. The suppression chamber 7 stores the suppression pool water 6 at the bottom. Further, an upper dry well 5 is provided above the pressure suppression chamber 7 so as to surround the reactor pressure vessel 2. The upper dry well 5 and the lower dry well 4 are communicated with each other by a communication hole 8. Each of the dry wells 4 and 5 and the suppression chamber 7 are connected to each other by a main vent pipe 9 extending into the suppression pool water 6.

Here, the containment vessel of the present embodiment is:
At least one lower drywell cooling unit 12A provided in the lower drywell 4 and at least one upper drywell cooling unit 12B provided in the upper drywell 5 are provided.

The former lower dry well cooling unit 12
A is configured to be able to cool the fluid in the lower dry well 4, that is, the atmosphere in the lower dry well 4 or the pool water for cooling the damaged core. The upper dry well cooling unit 12B is configured to be able to cool the atmosphere in the upper dry well 5.

These dry well cooling units 12
A and 12B each have a heat exchanger 10 and a casing 11 that houses the heat exchanger 10 (FIG. 2).
(See (a) and (b)). Among them, the heat exchanger 10 has a cooling coil (not shown) connected to a cooling water system, and by flowing cooling water into a pipe of the cooling coil, a fluid passing outside the pipe of the cooling coil is cooled. I can do it.

In the upper dry well 5, a blower 13 and a duct 14 corresponding to each of the dry well cooling units 12A and 12B are provided. In FIG. 1,
Only the blower 13 and the duct 14 corresponding to one lower drywell cooling unit 12A are shown, and the blowers 13 and the duct 14 corresponding to the other drywell cooling units 12A and 12B are omitted.

During normal operation of the reactor, the blower 1
3, each dry well cooling unit 12A, 12A
By sucking the atmosphere of the corresponding dry wells 4 and 5 into the casing 11 of B, and blowing the air cooled by the heat exchanger 10 through the duct 14 to various places in the upper dry well 5, The inside atmosphere is cooled to a specified state.

In this case, the atmosphere in the lower dry well 4 is circulated through the following route. That is, the atmosphere in the lower dry well 4 sucked into the lower dry well cooling unit 12A is
Is sent into the upper dry well 5 and blown out from the duct 14 into the upper dry well 5. On the other hand, the atmosphere in the upper dry well 5 flows into the lower dry well 4 through the communication hole 8 and is sucked into the lower dry well cooling unit 12A again.

Here, as shown in FIG. 2, the upper drywell cooling unit 12B is configured to suck the atmosphere from the opening 11a formed on one surface of the casing 11 (FIG. 2B). On the other hand, the lower drywell cooling unit 12A is configured to suck the atmosphere from openings 11a, 11a formed on two opposing surfaces of the casing 11 (FIG. 2A).

In this case, as shown in FIG. 3, the openings 11a in the casing 11 of the lower drywell cooling unit 12A are, for example, vertically opposed to each other.
It may be formed on a surface (FIG. 3A), or may be formed on two surfaces facing each other in the horizontal direction (FIG. 3B).

Here, as shown in FIG. 1, the lower drywell cooling unit 12A is disposed above the maximum deposition height H of the molten material deposited in the lower drywell 4 when the damaged core is discharged. The maximum deposition height H of this melt is
The deposition height (liquid level) when the entire amount of the core 1 and other structures in the reactor pressure vessel 2 is melted and deposited in the lower dry well 4.

The reactor containment vessel has a containment vessel cooling system that guides the pressure suppression pool water 6 by the pump P, removes the heat in the residual heat removal heat exchanger 16, and then sprays and cools the spray from the spray header 17. Is provided. In the event that LOCA occurs for some reason and a large amount of a mixture of high-temperature steam and water is discharged into each of the dry wells 4 and 5, the mixture of high-temperature steam and water is removed from the main vent. The water is guided into the suppression pool water 6 in the suppression chamber 7 through the pipe 9, and the internal pressure of the containment vessel is suppressed from rising.

Further, if a serious accident involving core damage (melting) occurs and the damaged core is discharged out of the reactor pressure vessel 2, cooling of the damaged core using an external water source and cooling of generated steam are performed. A spray for condensation is performed, and pool water for cooling the damaged core is stored in the lower dry well 4.

<Function and Effect> Next, the function and effect of the present embodiment having the above-described configuration will be described. First, in the reactor containment vessel of the present embodiment, when the damaged core is released outside the reactor pressure vessel 2, as described above, water injection or the like is performed using an external water source, and the damaged inside the lower dry well 4 is damaged. Core cooling pool water is stored. Then, steam is generated from the damaged core cooling pool water by the decay heat of the damaged core.

According to the present embodiment, the water injection and the like are continued, the water level of the damaged core cooling pool water in the lower dry well 4 rises, and the lower dry well cooling unit 1
When 2A is submerged, the lower drywell cooling unit 12
A directly cools the pool water (in this case,
The blower 13 has already been stopped by the isolation signal at the time of the accident).

As a result, the generation of steam from the damaged core cooling pool water is suppressed, and the amount of water injected and sprayed by the external water source can be reduced. That is,
It is possible to sufficiently cool the containment vessel without introducing a large amount of cooling water from an external water source.

Accordingly, it is possible to avoid excessive water storage in the containment vessel, and as a result, it is possible to suppress an increase in the internal pressure of the containment vessel. Therefore, even if a serious accident such as damage to the reactor core occurs, the increase in the internal pressure of the containment vessel can be effectively suppressed, and safety can be further improved.

The lower drywell cooling unit 12
Since A is disposed above the maximum deposition height H of the melt that deposits in the lower dry well 4 when the damaged core is discharged, the lower dry material is deposited by the melt that deposits in the lower dry well 4 when the damaged core is released. Well cooling unit 12A
Can be prevented from being damaged.

Further, the lower drywell cooling unit 1
2A has openings 11 on two opposing surfaces of casing 11.
Since the pool water for cooling the damaged core is cooled by the lower drywell cooling unit 12A, the high-temperature pool water heated by the damaged core is introduced into the casing 11 through the openings 11a and 11a. The pool water is cooled down by the heat exchanger 10 in the casing 11 while the pool water is effectively introduced.
The water flows out of 1a, 11a (see FIG. 2 (a)), and the cooling of the damaged core cooling pool water by the heat exchanger 10 in the casing 11 can be promoted.

The lower drywell cooling unit 12
The casing 11 of A may have openings 11a formed on other surfaces in addition to the two opposing surfaces as described above.

[Second Embodiment] Next, a second embodiment of the present invention will be described with reference to FIG. In the present embodiment shown in FIG. 4, the same components as those in the first embodiment shown in FIG. 1 are denoted by the same reference numerals, and detailed description will be omitted.

<Structure> As shown in FIG. 4, the reactor containment vessel of this embodiment has at least one (usually plural) upper dry well cooling unit 12B in the upper dry well 5, and Upper drywell cooling unit 12
A blower 13 and a duct 14 corresponding to B are provided.

Further, the containment vessel of the present embodiment is provided with the pressure suppression chamber 7 from inside the upper drywell cooling unit 12B.
Gas vent pipe 1 that communicates with the pressure suppression pool water 6
8 is provided. The tip opening 1 of the gas vent pipe 18
8a is opened in the suppression pool water 6 at a position higher than the opening 9a of the main vent pipe 9. The gas vent pipe 18 is provided with a check valve 19 for preventing a flow from the pressure suppression chamber 7 toward the upper drywell cooling unit 12B.

<Function and Effect> Next, the function and effect of this embodiment having the above-described configuration will be described. First, in the reactor containment vessel of the present embodiment, when the atmosphere in the upper dry well 5 is cooled by (the heat exchanger 10 of) the upper dry well cooling unit 12B, water vapor in the atmosphere is condensed. As a result, the atmosphere in the upper dry well containing the non-condensable gas such as nitrogen gas is sucked into the upper dry well cooling unit 12B.

According to this embodiment, the non-condensable gas sucked into the upper drywell cooling unit 12B can be discharged into the suppression pool water 6 of the suppression chamber 7 by the gas vent pipe 18. . Thereby, in the upper drywell cooling unit 12B,
Avoid deterioration of water vapor condensation due to accumulation of non-condensable gas,
The heat removal effect can be enhanced.

Therefore, as shown in FIGS. 7 (a) and 7 (b), in the event that a serious accident such as damage to the reactor core occurs, the pressure of the reactor containment vessel is reduced to condense the generated steam. In response to the rise, the time to start spraying from the external water source into the drywell can be delayed as compared with the conventional case, and even if the spray flow rate is reduced, the rise in the reactor containment pressure can be suppressed, so the reactor containment Excessive water storage in the container (suppression pool) can be avoided.

Therefore, even if a serious accident such as damage to the reactor core occurs, the internal pressure of the containment vessel can be effectively suppressed from increasing, and safety can be further improved.

Further, the distal end opening 18 of the gas vent pipe 18 is provided.
a is opened at a position higher than the opening 9a of the main vent pipe 9 in the pressure suppression pool water 6, the non-condensable gas sucked into the upper drywell cooling unit 12B is removed by the gas vent pipe 18 Thus, it can be efficiently discharged to the pressure suppression chamber.

Further, the gas vent pipe 18 is provided with a check valve 19 for preventing the flow from the pressure suppression chamber 7 side to the upper drywell cooling unit 12B side.
It is possible to prevent the pressure suppression pool water 6 from being sucked into the upper drywell cooling unit 12B through the gas vent pipe 18.

[Third and Fourth Embodiments] Next, third and fourth embodiments of the present invention will be described with reference to FIGS.

<Structure> First, the third embodiment shown in FIG. 5 uses a "normal cooling water system" in which ordinary cooling water indirectly cooled by seawater is used as cooling means in the lower drywell cooling unit 12A. And a “preliminary cooling water system” that directly uses seawater is provided in a switchable manner, and other configurations are the same as those of the first embodiment shown in FIGS. 1 to 3. .

The fourth embodiment shown in FIG. 6 is different from the fourth embodiment in that the above-mentioned “normal cooling water system” and the “preliminary cooling water system” are switchably provided as cooling means in the upper drywell cooling unit 12B. Unlike the second embodiment, other configurations are the same as those of the second embodiment shown in FIG.

As described above, the heat exchanger 10 in each of the drywell cooling units 12A and 12B has a cooling coil (not shown) connected to a cooling water system, and allows cooling water to flow through the tubes of the cooling coil. Thus, the fluid that passes outside the cooling coil can be cooled.

Therefore, in the third and fourth embodiments, in each of the drywell cooling units 12A and 12B, the cooling water flowing through the cooling coil of the heat exchanger 10 is used.
It is configured to be able to switch between normal cooling water from the “normal cooling water system” and seawater from the “preliminary cooling water system”.

More specifically, as shown in FIG. 5 or FIG. 6, the “common cooling water system” includes a common cooling line 20A connected to the heat exchanger 10 of each of the drywell cooling units 12A and 12B. A cooling seawater system 20B for cooling the cooling water flowing through the service cooling line 20A.

The former ordinary cooling line 20A is provided with a pump P2 for circulating cooling water and connected to a cooling load other than the drywell cooling units 12A and 12B. In the latter cooling seawater system 20B, a seawater heat exchanger 22 for indirectly cooling the cooling water flowing through the service cooling line 20A with seawater, and a pump P1 for flowing seawater to the seawater heat exchanger 22 are provided. Are provided.

The "preliminary cooling water system" is formed by bypassing the normal cooling line 20A and the cooling seawater system 20B with the preliminary cooling line 21. That is, the "preliminary cooling water system" is configured to flow seawater directly (by the action of the pump P1) to the service cooling line 20A via the preliminary cooling line 21.

From the viewpoint of promptly and accurately switching between the “normal cooling water system” and the “preliminary cooling water system” and proper operation, the auxiliary cooling line 21 is provided with a motorized valve capable of controlling flow rate and remote control. 24 (for outbound and return)
It is arranged.

<Operation and Effect> Next, the operation and effect of the third and fourth embodiments having the above-described configuration will be described. According to the third and fourth embodiments, in each of the first and second embodiments, even when the service water system becomes unusable for some reason, each dry well cooling unit 12A is used by the auxiliary water system. , 12B. For this reason, safety in the reactor containment vessel can be further ensured.

[Other Embodiments] The first to fourth embodiments of the containment vessel according to the present invention have been described above. However, from the viewpoint of pursuing higher safety, these first to fourth embodiments are described. A reactor containment vessel in which the above embodiments are appropriately combined may be used.

[0071]

According to the first to third aspects of the present invention, when the damaged core is released from the reactor pressure vessel, the damaged core cooling pool water stored in the lower dry well is supplied to the lower dry well cooling unit. By performing direct cooling, it is possible to sufficiently cool the reactor pressure vessel without introducing a large amount of cooling water from an external water source. For this reason,
Even if a serious accident such as damage to the reactor core occurs, the internal pressure of the containment vessel can be effectively suppressed from increasing and safety can be further improved.

According to the present invention, the non-condensable gas sucked into the upper drywell cooling unit can be discharged into the suppression pool water of the suppression chamber by the gas vent pipe. This allows
In the upper drywell cooling unit, deterioration of water vapor condensation due to accumulation of non-condensable gas can be avoided, and the heat removal effect can be enhanced. Therefore, even if a serious accident such as damage to the reactor core occurs, the increase in the internal pressure of the containment vessel can be effectively suppressed, and safety can be further improved.

[Brief description of the drawings]

FIG. 1 is a schematic longitudinal sectional view showing a schematic configuration of a first embodiment of a containment vessel according to the present invention.

2A is a schematic diagram of a lower drywell cooling unit in the reactor containment vessel shown in FIG. 1, and FIG. 2B is a schematic diagram of an upper drywell cooling unit.

FIG. 3 is a schematic perspective view showing an arrangement variation of a casing opening in a lower drywell cooling unit of the containment vessel shown in FIG. 1;

FIG. 4 is a schematic longitudinal sectional view showing a schematic configuration of a second embodiment of the containment vessel according to the present invention.

FIG. 5 is a schematic longitudinal sectional view showing a schematic configuration of a third embodiment of the containment vessel according to the present invention.

FIG. 6 is a schematic longitudinal sectional view showing a schematic configuration of a fourth embodiment of the containment vessel according to the present invention.

7A and 7B are graphs for explaining the operation and effect of the containment vessel according to the present invention, wherein FIG. 7A is a graph showing the relationship between the elapsed time after the accident and the containment pressure, and FIG. The graph which shows the relationship between the elapsed time after an accident and the water level of the suppression pool.

FIG. 8 is a schematic longitudinal sectional view showing a schematic configuration of a conventional reactor containment vessel.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Reactor core 2 Reactor pressure vessel 3 Pedestal 4 Lower dry well 5 Upper dry well 6 Suppression pool water 7 Suppression chamber 8 Communication hole 9 Main vent pipe 10 Heat exchanger 11 Casing 12A Lower drywell cooling unit 12B Upper drywell cooling Unit 13 Blower 14 Duct 18 Gas vent pipe 19 Check valve 20A Service cooling line 20B Cooling seawater system 21 Pre-cooling line

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Seiichi Yokobori 1 Koko Toshiba-cho, Saiwai-ku, Kawasaki-shi, Kanagawa Prefecture Toshiba R & D Center (72) Inventor Ryoichi Hamasaki Isogo-ku, Yokohama-shi, Kanagawa 8 Shin-Sugita-cho F-term in Toshiba Yokohama Office (reference) 2G002 AA03 BA01 BA07 CA01 DA01 EA01

Claims (7)

[Claims] 1. A reactor pressure vessel containing a reactor core, a substantially cylindrical pedestal supporting a lower portion of the reactor pressure vessel, and release of a damaged reactor core from the reactor pressure vessel while being surrounded by the pedestal A lower drywell for storing pool water for cooling the sometimes damaged core, a pressure suppression chamber provided surrounding the pedestal and storing a pressure suppression pool water at the bottom, and a reactor located above the pressure suppression chamber, An upper dry well provided surrounding the pressure vessel; and at least one lower dry well cooling unit provided in the lower dry well and configured to cool a fluid in the lower dry well. A reactor containment vessel characterized by the above. 2. The atom according to claim 1, wherein said lower drywell cooling unit is disposed above a maximum deposition height of a melt deposited in said lower drywell when said damaged core is discharged. Furnace containment vessel. 3. The lower drywell cooling unit has a heat exchanger for cooling a fluid in the lower drywell, and a casing for accommodating the heat exchanger. The containment vessel according to claim 1 or 2, wherein an opening for sucking an atmosphere in the lower drywell is formed in the surface. 4. A reactor pressure vessel having a reactor core therein, a substantially cylindrical pedestal supporting a lower portion of the reactor pressure vessel, and a damaged core being released from the reactor pressure vessel while being surrounded by the pedestal. A lower drywell that sometimes stores pool water for cooling the damaged core, a pressure suppression chamber that is provided surrounding the pedestal, and stores a pressure suppression pool water at the bottom. An upper dry well provided around the pressure vessel, at least one upper dry well cooling unit provided in the upper dry well and configured to cool an atmosphere in the upper dry well; A gas vent pipe communicating from inside the well cooling unit to the water in the suppression pool of the suppression chamber. Paid container. 5. The apparatus according to claim 5, further comprising a main vent pipe communicating from inside the upper drywell and the lower drywell to the suppression pool water in the suppression chamber, wherein the gas vent pipe is connected to the main vent pipe in the suppression pool water. The containment vessel according to claim 4, wherein the containment vessel is open at a position higher than the vent pipe. 6. The reactor containment according to claim 4, wherein a check valve for preventing a flow from the pressure suppression chamber side to the upper drywell cooling unit side is provided in the gas vent pipe. container. 7. The cooling means in each drywell cooling unit is provided so as to be switchable between a normal cooling water system using cooling water indirectly cooled by seawater and a preliminary cooling water system using seawater directly. Claim 1 or 4
A containment vessel as described.