JP2005062059A - Boiling water type nuclear power plant - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a boiling water type nuclear power plant which reduces partition walls constituting each building, and improves economy and safety by making a large space around a reactor pressure vessel (1). <P>SOLUTION: By combining a reactor building 18 and a turbine building 30, a reactor turbine containment vessel 117 is made and the reactor pressure vessel 1 and ECCS and a turbine equipment are contained together. A rigid sealed large space is made with a cylindrical large containment vessel wall 116, an openable containment vessel seal lid 201 and an openable containment structure lid 202. The openable containment vessel seal lid 201 and an openable containment structure lid 202 are fastened with bolts 204 by an openable containment vessel strap 203 to the large containment vessel wall 116 to be opened. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention particularly relates to a containment vessel for a boiling water nuclear power plant.

FIG. 1 is an example of the layout of buildings that contain the devices that constitute a boiling water nuclear power plant. Waste building for processing radioactive waste generated during operation of boiling water nuclear power plant, reactor pressure vessel (1) housed in containment vessel (15) to provide sealed space, emergency core cooling system (ECCS) ) Containing a nuclear reactor building (18), a ventilation machine room, a high pressure turbine (103), a low pressure turbine (104), a generator (102), and a turbine building containing a condenser (105) (105). 30), comprising a control room for controlling each device including the nuclear reactor.
The reactor building (18) and the turbine building (30) are separated to prevent the reactor pressure vessel (1) from being damaged by the kinetic energy when the turbine, which is a dynamic device, fails. In order to cope with the thermal expansion of the steam pipe (13) for guiding the steam generated in the reactor pressure vessel (1) to the high-pressure turbine (103), it is conceivable to secure a distance for routing the pipe.
FIG. 2 is a schematic view showing the inside of the reactor building (18). The reactor pressure vessel (1) includes a recirculation pump drive motor (2) for containing nuclear fuel and circulating water as a coolant, and a control rod drive mechanism (3) for controlling the reactor output.
Above the reactor pressure vessel (1) are a storage pool (5) for storing spent nuclear fuel and a working pool (4) for temporarily storing the internal structure of the reactor at the time of inspection.
When the steam pressure in the reactor pressure vessel (1) becomes excessively high, excess steam opens the relief safety valve (6) in the middle of the steam pipe (13), passes through the relief valve pipe (7), and the pressure suppression pool ( 9) Enter and cool. The pressure suppression pool (9) consists of a pool wall (10), a horizontal vent (11) and a weir (12).
The containment vessel (15) is sealed with a sturdy containment vessel wall (16) and contains a reactor pressure vessel (1), a pressure suppression pool (9), and ECCS. The water in the pressure suppression pool (9) is also the water source for ECCS.
The reactor building (18), which protects the reactor pressure vessel (1) from the external natural environment, is covered with a relatively sturdy reactor building wall (17) and, together with the containment vessel (15), Making radioactivity confinement stronger. When the level of radiation in the reactor building (18) increases, the atmosphere in the reactor building (18) is slowly released from the stack (20) to the outside air through the ventilation system (19) with a filter. .
When the inside of the containment vessel (15) is inspected, the inspection access hatch (21) that is closed during the operation of the nuclear reactor is opened, and objects and people enter and exit.
Gamma rays and radiant heat from the reactor pressure vessel (1) are shielded by the iron shielding wall (22).
The containment vessel (15) and the reactor building (18) are fixed on the foundation concrete (23) dug in the soil (25) and laid on the hard ground (24) below.
FIG. 3 is an overview of a conventional turbine building (30). Steam generated in the reactor pressure vessel (1) passes through the steam pipe (13), enters the high-pressure turbine (103), passes through the low-pressure turbine (104), is cooled by the condenser (105), becomes water, and becomes a water supply pipe. Return to reactor pressure vessel (1) through (14).
The generator (102) is rotated by a high pressure turbine (103) and a low pressure turbine (104) to generate electric power.
The condenser (105) is cooled by seawater introduced by the seawater circulation pump (161) and the seawater circulation pipe (160), and converts low-temperature and low-pressure steam emitted from the low-pressure turbine (104) into water. The warm seawater returns to the sea from the discharge channel.

In the boiling water nuclear power plant, the steam generated in the reactor pressure vessel (1) goes to the turbine facility and returns to the reactor pressure vessel (1) as water.
Steam and water in the reactor pressure vessel (1) and steam and water in the turbine equipment are directly connected, so steam leakage due to a failure in the turbine equipment causes a loss of coolant from the reactor pressure vessel (1). Is the same. Therefore, the turbine building (30) also has the same robustness and sealing performance as the reactor building (18).
At the beginning of the reactor development, the reactor building (18) and the turbine building (due to the lack of construction technology for large, robust buildings and the difficulty in routing the steam pipe (13) and water supply pipe (14) ( And 30) were built separately. Even now that construction technology and piping materials have advanced, it has been followed to build separately to respect the achievements.
In preparation for leakage of coolant from the steam pipe (13) and water supply pipe (14) having a long distance from the steam outlet of the reactor pressure vessel (1) to the water supply inlet, there are many isolation valves and walls in the middle. Is provided. This causes not only high construction and manufacturing costs, but also costs due to the necessity of frequent inspections and repairs, resulting in high power generation costs.
In addition, life extension of existing power plants is being researched due to difficulties in location and demands for reducing power generation costs. In the replacement of a large structure, a part of the reactor building (18) is broken to extend the life by replacement. The complexity and duration of the work will be considerable, and the power generation cost will naturally increase. A nuclear power plant that presupposes frequent replacement is desired.

FIG. 4 is a layout view of the building of the present invention including the devices constituting the boiling water nuclear power plant. Previously separated reactor building (18) and turbine building (30) are combined into a reactor turbine containment vessel (117), and contain reactor pressure vessel (1), ECCS and turbine equipment together. To do.
FIG. 5 is a schematic view of the inside of the reactor turbine containment vessel (117). A large cylindrical containment vessel wall (116) made of reinforced concrete or prestressed concrete, an openable containment container sealing lid (201), and an openable containment container structural lid (202) provide a sturdy sealed large space. The openable storage container sealing lid (201) and the openable storage container structure lid (202) can be bolted (204) to the large storage container wall (116) by the storage container band (203).
As a coolant adjusting device when the steam pressure in the reactor pressure vessel (1) becomes excessive, the relief valve pipe (7) connected from the relief safety valve (6) to the pressure suppression pool (9) is an upper relief valve pipe. (113) and the working pool (4) so that excess steam escapes to the surface layer, and a pipe (114) with a water check valve is attached to the lower layer of the storage pool (5) connected to the working pool (4). When the internal pressure of the storage pool (5) connected to the pool (4) becomes the same as the internal pressure of the reactor pressure vessel (1), the lower level of the storage pool (5) is the internal pressure of the reactor pressure vessel (1) due to the head differential. Therefore, the water in the storage pool (5) was dropped and injected into the reactor pressure vessel (1) from the pipe with a water check valve (114). The pipe with a water check valve (114) is connected to the water supply pipe (14) or the reactor pressure vessel (1). The isolation valve attached to the steam pipe (13) was one electric isolation valve for stopping the turbine equipment. The valve attached to the water supply pipe (14) was also one check valve for stopping the turbine equipment. In order to increase reliability, the number is set to two. In addition, as a pipe whip countermeasure, it can be prevented by spirally winding the periphery of the pipe with glass fiber reinforced plastic.
The reactor pressure vessel (1) was surrounded by a reinforced concrete cylindrical wall (108) that protected the reactor pressure vessel (1) from turbine missiles and supported the work pool (4) and the storage pool (5). The cylindrical wall (108) is provided with a doorless opening inspection access cylinder (121) through which the steam pipe (13) and the water supply pipe (14) pass, and objects and people enter and exit during the inspection. The atmosphere around the reactor pressure vessel (1) in the cylindrical wall (108) is connected to the entire reactor turbine containment vessel (117) even during operation.
A shield water tank (122) was provided inside the cylindrical wall (108) instead of the conventional shield wall (22), and a steam passage was formed between the reactor and the reactor pressure vessel (1). Steam leaked due to damage to the reactor pressure vessel (1) passes through a steam passage formed between the shielding water tank (122) and the reactor pressure vessel (1), and there is no door provided on the cylindrical wall (108). Waste building in the nuclear power plant site management area flows out from the open inspection access cylinder (121) to the entire reactor turbine containment vessel (117) and from the downward exhaust pipe (120) through the ventilation system with a filter (19) Or it is discharged into a freshwater pond in a greenhouse dome or a reactor building in a decommissioning reactor. The noncondensable gas in the condenser (105) is discharged from the downward exhaust pipe (120) through the ventilation system (19).
When steam leaks from the reactor pressure vessel (1) into the cylindrical wall (108), the reactor pressure vessel (1) is cooled because it is cooled by adiabatic expansion. When steam leaks from the doorless opening inspection access cylinder (121) into the reactor turbine containment vessel (117), the cylindrical wall (108) is cooled because it is cooled by adiabatic expansion. The steam that has leaked into the reactor turbine containment vessel (117) is discharged from the down stack (120) into the nuclear power plant site management area through the ventilation system (19), and therefore, inside the reactor turbine containment vessel (117). Heat removal and pressure reduction.
The turbine equipment was installed on a concrete stack (140) for height adjustment. Cooling for converting the steam from the reactor pressure vessel (1) that has entered the condenser (105) into water is performed by a fresh water pool (150) constituted by a fresh water pool wall (151) and a large containment vessel wall (116). ) By cold fresh water pumped from near the bottom by a condensate circulation pump (153) and a condensate pipe (152). Water is discharged on the surface of the freshwater pool (150). Arrows indicate the direction of steam or water flow.
Seawater for cooling the freshwater pool (150) is pumped up by the seawater circulation pump (161) and discharged into the sea through the water discharge channel.
The water in the fresh water pool (150) is also used as a water source for the ECCS and the shielding water tank (122). It is also used as the water source and discharge destination of the control rod drive mechanism (3).
A hydrous porous body (130) was placed under the reactor pressure vessel (1).
An emergency water inlet (170) was provided below the large containment vessel wall (116). When the water in the fresh water pool (150) is insufficient, the fresh water pool (150) is appropriately replenished with water from the emergency water injection port (170) even during normal times.

Although the conventional containment vessel (15) shown in FIG. 2 was a small space around the reactor pressure vessel (1), the reactor turbine containment vessel (117) of the present invention shown in FIG. ) + Conventional reactor building (18) + conventional turbine building (30). As a result, the partition walls constituting each building were reduced and the economy was improved. Even if the reactor pressure vessel (1) and the turbine equipment are installed in the reactor vessel containment vessel (117) of the same vessel, the steam pipe (13) or the water supply pipe (14) is damaged and the coolant leaks. Since it can be managed in the nuclear reactor turbine (117), it is only necessary to provide one isolation valve for the steam pipe (13) and one check valve for the water supply pipe (14) for stopping the turbine, thus improving the economy. .
Furthermore, even if the reactor pressure vessel (1) is damaged, the destructive force such as steam pressure is reduced by the large space, and safety is improved.
In the present invention, because of the soundness of the nuclear reactor containment vessel (117) that contains highly radioactive solid or liquid fission products, the high-temperature and high-pressure steam that leaked due to an accident failure is directed downward through the purification system (19) with a filter. Although it is discharged from the stack (120) into the site management area of a nuclear power plant such as a waste building, the water quality management of the boiling water reactor is aimed at pure water, so there are few impurities, so the radioactivity is low and nuclear power generation. There is no strong radioactivity outside the site. As safety increases, consideration of wide area damage countermeasure costs will decrease and power generation costs will be reduced.
In the unlikely event that the reactor pressure vessel (1) breaks and the high temperature melt falls, the hydrous porous body (130) provided at the bottom of the reactor pressure vessel (1) Since it can be cooled and solidified, the soundness of the reactor turbine containment vessel (117) can be secured. Therefore, it is possible to improve safety by preventing the fission product of solid or liquid having high radioactivity from being scattered outside the site of the nuclear power plant. You can build as many nuclear power plants as you need.
Although the conventional condenser (105) cooling was seawater, in the present invention, the condenser (105) cooling uses fresh water from a fresh water pool (150) installed in the reactor turbine containment vessel (117). Since there is less risk of seawater entering the reactor pressure vessel (1), water quality management becomes easier and costs are reduced. In addition, the water in the fresh water pool (150) also becomes a water source for ECCS, and the conventional pressure suppression pool (9) is not required, thereby reducing costs.
In the present invention, when the steam suddenly increases due to an abnormality in the reactor pressure vessel (1), the excess steam escaped from the relief safety valve (6) to the work pool (4) through the upper relief valve pipe (113). . The working pool (4) in operation was useless space and water, but it could be used effectively. The water with a water check valve (114) connected to the adjacent storage pool (5) can effectively use the water in the storage pool (5) as make-up water to the reactor pressure vessel (1), resulting in cost reduction.
Since the ceiling of the reactor turbine containment vessel (117) is opened and closed by the openable containment vessel sealing lid (201) and the openable containment vessel structure lid (202), the upper lid and the trunk of the shroud or the reactor pressure vessel (1) Such large parts became easy to replace every few decades. It can be used for a long time without leaving the nuclear power plant.

If the pressure in the reactor pressure vessel (1) rises excessively, excess steam enters the work pool (4) from the top relief valve pipe (113) and is cooled to water. When the amount of steam is large and the pressure in the work pool (4) rises, the pressure in the storage pool (5) communicating with the work pool (4) also rises, and the pressure in the reactor pressure vessel (1) At the same time, since the pressure of the water head difference is applied to the pipe (114) with a water check valve at the bottom of the storage pool (5), the water in the storage pool (5) is put into the reactor pressure vessel (1). It falls and water is poured. The amount of cooling water in the reactor pressure vessel (1) is automatically adjusted.
If a part of the reactor pressure vessel (1) breaks and water leaks, the ECCS operates and receives water supply as before, but the leaked water is provided inside the cylindrical wall (108). It leaks into the steam passage formed by the shielding water tank (122) and the reactor pressure vessel (1). The reactor pressure vessel (1) is cooled by the adiabatic expansion at that time. The steam released into the space in the cylindrical wall (108) is released from the opening inspection access cylinder (121), which is partially open during operation, to the entire reactor turbine containment vessel (117). At this time, the cylindrical wall (108) is cooled by adiabatic expansion. Vapor in the reactor turbine containment vessel (117) passes through a ventilation system (19) with a filter and is directed downward from the stack (120) to the waste building, decommissioning building, and greenhouse dome in the nuclear power plant site management area. Steam is released into the inner freshwater aqua pond, and heat removal and pressure reduction in the reactor turbine containment vessel (117) can be achieved. The water quality management of boiling water reactors is managed with pure water as the target, and the development of nuclear fuel rods has led to almost no damage in recent years, so steam and water in boiling water reactors have little radioactivity. Because of the low radioactivity of steam, it can be released into the site management area of nuclear power plants.
Even if there is no cooling water in the reactor pressure vessel (1) and the nuclear fuel rod is damaged on a large scale, the reactor turbine containment vessel (117) is still at the pressure of the fission product volatile gas accumulated in the nuclear fuel rod. Will not break down, so that radioactive solid or liquid fission products will be trapped in the reactor turbine containment (117). The radioactivity of volatile gases is weakened in a short time and the amount is not large, so it can be discharged through a filter to a waste building in a nuclear power plant site management area, a decommissioning building, or a freshwater aquaculture pond in a greenhouse dome. The surrounding environment can be prevented from being contaminated by compressing and storing it in a cylinder. Since the steam in the reactor turbine containment vessel (117) can be released to the outside from the time when the radioactivity level does not rise from the time when the steam leakage occurs, the soundness of the reactor turbine containment vessel (117) can be ensured.
When the nuclear fuel rod is heated excessively and melts on a large scale, and the reactor pressure vessel (1) is also melted, the high-temperature melt falls into the hydrous porous body (130) under the reactor pressure vessel (1). . Since the contact area between the high-temperature melt and water is limited by the porous body, the contact area between the high-temperature melt and water is reduced, and the high-temperature melt is cooled and solidified by evaporation without causing a large-scale vapor explosion. The steam cools the reactor pressure vessel (1) while passing through the passage between the shielding wall (108) and the reactor pressure vessel (1), and lowers the temperature inside. As the water-containing porous material, for example, a water containing an antiseptic is included in a porous material of alumina brick or zirconia brick, a hollow fiber membrane, agar, straw, polyurethane, or sodium acrylate polymer. For further water supply to the water-containing porous body (130), a water tank may be installed under the concrete laminate (140).
Although the condenser (105) is conventionally cooled with seawater, in the present invention, the cold water at the bottom of the fresh water pool (150) built in the reactor turbine containment vessel (117) is used as a condensate pipe. The water is pumped up by the condensate circulation pump (153) through (152) and cooled. The water is discharged near the surface. Since it is fresh water, there is no risk of salt water entering the condenser (105), so there is no concern that salt water will be brought into the reactor pressure vessel (1). No damage to nuclear fuel rods or equipment due to salt damage. The water in the fresh water pool (150) is used not only for cooling the condenser (105) but also as a water source for ECCS, the control rod drive mechanism (3) and the fire hydrant.
The freshwater pool (150) is cooled by pumping seawater with a seawater circulation pump (161).
Final cooling of the reactor pressure vessel (1) is achieved by water injection from the emergency water injection port (170) to the reactor turbine containment vessel (117). Water injection from fire engines and freshwater ponds in the greenhouse dome is also possible.
The ceiling of the cylindrical large containment vessel wall (116) can be opened and closed by an open / close type containment container sealing lid (201) and bolts (204) fixed to the containment belt band (203) and an open / close type containment vessel structure lid (202). did.
The cylindrical wall (108) serves to protect the reactor pressure vessel (1) from turbine missiles due to turbine failure. Since the turbine system becomes long, it is preferable to arrange it at the center of the reactor turbine containment vessel (117).
The shielding water tank (122) shields radiant heat and gamma rays from the reactor pressure vessel (1) and protects the soundness of the structure including the cylindrical wall (108). Since the main component is water, the amount of radioactive waste is reduced, and in the event of an emergency, the reactor turbine containment vessel (117) is also cooled.
In addition, since the low pressure turbine (104) was accommodated in the reactor turbine containment vessel (117), there was a margin for the failure of the low pressure turbine (104) and the steam temperature entering the low pressure turbine (104) was 280. Since the temperature is less than C, the body and blades of the low-pressure turbine (104) can use inexpensive polyimide resin or glass fiber reinforced plastic.

FIG. 6 shows an example in which the present invention is partially applied to a boiling water nuclear power plant in which a reactor building (18) and a turbine building (30) currently in operation are separated. Only the reactor building (18) is applicable.
The relief valve pipe (7) from the relief safety valve (6) is an upper relief valve pipe (113) that is allowed to escape to the work pool (4), and the water injection check valve-attached pipe (114) is provided in the storage pool (5). Provided. The outlet of the upper relief valve pipe (113) was positioned higher than the inlet of the pipe with a water check valve (114).
Excess steam in the reactor pressure vessel (1) is discharged from the top relief valve pipe (113) to the working pool (4). When the discharge steam becomes excessive and the pressure in the storage pool (5) communicating with the work pool (4) becomes the same as the pressure in the reactor pressure vessel (1), the inlet pressure of the water injection check valve pipe (114) Therefore, the water in the storage pool (5) drops and is poured into the reactor pressure vessel (1) through the pipe (114) with a water check valve. Even if the water in the storage pool (5) is exhausted, the decay heat of the spent nuclear fuel that has passed a periodic inspection time of 10 days or more is sufficiently small, so the storage pool passes through the pipe (114) with a water injection check valve. Even if the water in (5) runs out, there is no problem if the period is short.
A hydrous porous body (130) is laid at the bottom of the reactor pressure vessel (1).
Unlike pools, the area of contact with water is limited by the porous material, so even if a high-temperature melt falls, the water will gradually evaporate without a large-scale steam explosion. The heat of 1) is discharged from the outside through the vent pipe (8) into the pressure suppression pool (9). For further water supply to the hydrous porous body (130), water in the pressure suppression pool (9) is supplied from the weir (12) through the horizontal vent (11).
Ultimate cooling of the reactor building (18) is accomplished by water injection from the emergency water injection port (170).
When part of the reactor building (18) is broken and large equipment such as a shroud is replaced, in order to facilitate the next replacement, the containment belt (203) and open / close type storage in the reactor building (18) after the repair is completed The reactor building (18) is modified by the container sealing lid (201) and the openable containment vessel structure lid (202).

This is an example in which the present invention is applied to a conventional nuclear reactor building (18).
The inspection access hatch (21) is partially open during operation. When steam leaks from the reactor pressure vessel (1) due to an accident and the internal pressure of the containment vessel (15) increases, the steam is insulated from the inspection access hatch (21), which is partially open, into the reactor building (18). The reactor pressure vessel (1) is cooled by expansion and cooling. Vapor is released from the ventilation system (19) through the down stack (120) to the waste building or decommissioning building in the nuclear power plant site management area, the surface bag, or the freshwater aquaculture pond in the newly established greenhouse dome . The conventional exhaust pipe (20) is plugged.
It is possible to suppress the influence of radioactivity as far as possible to a populated place far away from the nuclear power plant. Environmental pollution in the nuclear power plant is minimal because the steam released from the point that the water quality management of boiling water reactors targets pure water is low.

About 20 boiling water nuclear power plants have been built and are operating in Japan. Construction is planned in the future and the number of bases is expected to continue to increase, but the accident probability of the entire nuclear power plant will inevitably increase, and there will be a need to increase the safety of individual nuclear power plants. On the other hand, it is necessary to increase the price competitiveness of nuclear power generation as the power generation costs such as thermal power generation have started to fall. Therefore, safety must be improved while reducing the construction cost of nuclear power plants.
Since the boiling water nuclear power plant using the nuclear reactor containment vessel (117) of the present invention improves the safety while reducing the construction cost, the applicability is very high. Moreover, since a new material is not required for the present invention, the development period is considered to be as short as several years.
Furthermore, due to the technical problems such as the upper relief valve pipe (113), the water injection check valve pipe (114), the water-containing porous body (130) and the openable / container containment cover (202) incorporated in the present invention The concept of protecting the containment vessel (15) by escaping the steam leaked from the reactor pressure vessel (1) into the nuclear power plant site management area through the downward stack (120) is the boiling water type currently in operation. It can also be applied to nuclear power plants.

The example of arrangement | positioning of the building which encloses the apparatus which comprises the conventional boiling water nuclear power plant. Overview of the conventional reactor building (18) Overview of conventional turbine building (30) The example of arrangement | positioning of the building which includes the apparatus which comprises the boiling water nuclear power plant of this invention. Overview of the reactor turbine containment vessel (117) of the present invention The Example at the time of applying this invention in the conventional nuclear reactor building (18).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Reactor pressure vessel 2 Recirculation pump drive motor 3 Control rod drive mechanism 4 Work pool 5 Storage pool 6 Relief safety valve 7 Relief valve tube 8 Vent tube 9 Pressure suppression pool 10 Pool wall 11 Horizontal vent 12 Weir 13 Steam piping 14 Water supply piping DESCRIPTION OF SYMBOLS 15 Containment vessel 16 Containment vessel wall 17 Reactor building wall 18 Reactor building wall 19 Ventilation system 20 Exhaust pipe 21 Inspection access hatch 22 Shielding wall 23 Foundation concrete 24 Ground 25 Earth 30 Turbine building 102 Generator 103 High-pressure turbine 104 Low-pressure turbine 105 Recovery Water vessel 108 Cylindrical wall 113 Upper relief valve tube 114 Water injection check valve tube 116 Large containment vessel wall 117 Reactor turbine containment vessel 120 Downward exhaust cylinder 121 Opening inspection access cylinder 122 Shielded water tank 130 Hydrous porous body 140 Concrete layer 150 Fresh water Pool 15 DESCRIPTION OF SYMBOLS 1 Freshwater pool wall 152 Condensate piping 153 Condensate circulation pump 160 Seawater piping 161 Seawater circulation pump 170 Emergency water injection port 201 Opening and closing type containment vessel sealing lid 202 Opening and closing type containment vessel structure lid 203 Containment vessel belt 204 bolt (204)

Claims (6)

  In a boiling water nuclear power plant, the reactor pressure vessel (1), ECCS, and turbine equipment are enclosed by a large cylindrical containment vessel wall (116) made of reinforced concrete or prestressed concrete. ) And an open / close-type containment vessel structure lid (202) are bolted (204) to the containment vessel band (203) so that the ceiling can be opened and closed (117).   Excess steam in the reactor pressure vessel (1) escapes from the relief safety valve (6) through the upper relief valve pipe (113) to the work pool (4), and communicates with the work pool (4) when the amount of steam further increases. The water in the storage pool (5) falls into the reactor pressure vessel (1) by using the water head difference from the pipe (114) with a water injection check valve located at the bottom of the storage pool (5). A coolant adjusting device characterized by that.   The reactor pressure vessel (1) is surrounded by a cylindrical wall (108) made of reinforced concrete that supports the work pool (4) and the storage pool (5), and a shielding water tank (122) is provided inside the reactor pressure vessel (1). ) Is formed, and the cylindrical wall (108) is provided with a doorless opening inspection access cylinder (121) that is open even during operation, and leaked steam from the reactor pressure vessel (1) is removed from the reactor turbine containment vessel (1). 117) The steam discharged to the whole and discharged into the reactor turbine containment vessel (117) passes through the ventilation system (19) with a filter and is disposed from the down stack (120) in the site management area of the nuclear power plant. An apparatus for promoting cooling of a reactor pressure vessel (1), characterized in that steam is discharged to a building building, a decommissioning building, or a freshwater pond in a greenhouse dome.   A condensate circulation pump (153) and a condensate pipe (152) are formed from near the bottom of the fresh water pool (150) constructed in the reactor turbine containment vessel (117) by the fresh water pool wall (151) and the large containment vessel wall (116). Cold water is pumped to the condenser (105) and discharged to the surface of the freshwater pool (150). The freshwater pool (150) is cooled by pumping seawater with the seawater circulation pump (161) and discharging it to the sea through the discharge channel. The cooling device of the condenser (105) characterized.   A reactor containment vessel characterized in that a hydrous porous body (130) is provided under the reactor pressure vessel (1) in order to cool the high-temperature molten fallen material from the reactor pressure vessel (1).   Reactor building characterized in that water is injected from an emergency water injection port (170) as cooling in the reactor building (18).

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