JPH05203778A - Static system for controlling concentration of burnable gas - Google Patents

Abstract

PURPOSE:To efficiently reduce hydrogen gas generating within a reactor containment, by effectively utilizing the stream of the atmosphere of the space within the containment, at time of an accident. CONSTITUTION:The primary piping 4 of a reactor passes through an upper dry well 6 through a separation valve 5 from a pressure vessel 3 incorporating the reactor 1 and the primary cooling water 2 of the reactor. A lower dry well 7 is set below the vessel 3, and communicates with the vessel 3 through the space of the side of the vessel 3. The bottom part of the well 6 consists of a diaphragm floor 8, and the space part 10 of a pressure control chamber having a pressure control pool 9 is set below it. The well 6 and the pool 9 communicate by a vent pipe 11, and openings 12 in water of the pipe 11 to the pool 9 are horizontally set, separated into vertical three stages.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for reducing the hydrogen gas concentration in a closed container, and is particularly effective when the container is a pressure suppression reactor containment vessel of a light water nuclear power plant. The present invention relates to a device for reducing the hydrogen gas concentration in the reactor containment vessel.

[0002]

2. Description of the Related Art In a light water nuclear power plant, hydrogen and oxygen are generated in a nuclear reactor due to radiolysis of water as a coolant in the event of a loss of coolant. Further, when the temperature of the fuel cladding is increased, hydrogen gas is generated by the water-metal reaction between zirconium in the fuel cladding and steam. These hydrogen gases are released into the reactor containment vessel from the breakage portion of the reactor primary coolant boundary, and the hydrogen gas concentration in the reactor containment vessel gradually rises. If this state is left unattended, it becomes flammable in an atmosphere with a hydrogen gas concentration of 4 vol% or more and an oxygen gas concentration of 5 vol% or more, and if the hydrogen gas concentration further increases, there is a danger of explosion. -Type nuclear power plant draws an atmosphere containing hydrogen gas from the containment vessel with a blower, heats it with an electric heater to recombine hydrogen and oxygen into water, cools the remaining atmosphere gas with a cooler, and then returns it to the containment vessel. A recombinable flammable gas concentration control system is used.

In some nuclear power plants having a large containment vessel, a strong ignition system called an igniter is adopted.

Recently, it has been proposed that the existing blowers, heaters and the like which do not use strong driving force or electricity are disclosed in Japanese Patent Laid-Open No. 62-
As described in 202802 or Japanese Patent Laid-Open No. 1-176045, a catalyst-type hydrogen adsorbent is spirally wound in a closed container, or a blind-folded one is hung in the air in a containment vessel as necessary. Sometimes the airtight container is opened, and the catalytic hydrogen adsorbent inside is hung down in the atmosphere of the containment vessel, a blind shape is extended downward, or something like a brand that hangs down. Invented.

The International Topical Meeting of the A. N. S Portland / Oregon USS, Jurai 21-25-19
91 safety of thermal reactor (Internatio
nal Topical Meeting of the A.NS Portland / Oregon,
USA, July 21-25-1991 Safety of Therma
l Reactors) has announced a hydrogen gas concentration suppressor for large dry containment vessels that uses a ceiling-suspended catalytic hydrogen adsorbent.

As described above, in these recent examples, those which require a large space in the vertical direction and those which are always hung from the ceiling are static (without using power or electric power) combustible gas concentration control system. Although it can be installed in a large-sized storage container, there is a drawback in that it cannot be installed in a small-sized storage container such as a pressure suppression type storage container because there is no space.

Further, since the suspension system is used, there is a drawback that it is a hindrance when working, especially in a small-sized storage container at the time of rating.

[0008]

The present invention is suitable for a relatively small containment vessel such as a pressure suppression type reactor containment vessel, and effectively reduces the hydrogen gas concentration without using power or electric power. It is to provide a static combustible gas concentration control system.

[0009]

The present invention comprises two methods,
And a method relating to combining them.

One of the inventions is claims 1 to 6 and 11.
It is solved by a device having various characteristics. This device focuses on the long-term atmospheric flow between the drywell and the pressure suppression chamber in the event of a loss of coolant in the pressure suppression reactor containment vessel, and is designed to absorb hydrogen gas effectively and efficiently. I have to. Particularly, when the system has a system for returning the atmosphere in the dry well to the pressure suppression pool while cooling it with an IC (isolation condenser), the present invention enhances the cooling effect (vapor condensation effect) of the IC, and the dry well atmosphere to the IC It is focused on having another effect of further promoting the containment vessel cooling effect by the IC because it has a function of increasing the suction flow rate.

Further, in the case of a containment vessel having a containment vessel vent system (extraction system) used in the unlikely event of an excessively large containment vessel internal pressure, hydrogen gas released from the containment vessel to the outside of the containment vessel. However, in order to prevent the risk of explosion outside the containment vessel by mixing with oxygen gas in the outside air, hydrogen gas in the atmosphere inside the containment vessel that flows into the vent system should be effectively and efficiently absorbed. There is.

The second point of the invention is that the flow of the dry well and the pressure suppression chamber or the flow of the vent from the storage container is not expected, that is, there is no flow between the partitioned spaces. Even in such a case, the atmospheric gas containing hydrogen gas is efficiently brought into contact with the catalytic hydrogen adsorbent by the natural circulation flow in the dry well or in the pressure suppression chamber. This is achieved by a device having the features of claims 7-11. This device can be installed on a vertical wall, a ceiling wall, anywhere due to space limitations or natural circulation, at any angle, and along a wall that does not interfere when not in use. Keep it in place to prevent dust and oil dust from adhering to the catalytic hydrogen adsorbent, which could reduce the performance of the catalytic hydrogen adsorbent, and automatically or manually when necessary, in a prescribed position at a prescribed orientation. The catalyst type hydrogen adsorbent can be set.

Furthermore, the combination of the above two inventions and the simultaneous implementation thereof are achieved by the constitution having the features of claim 11.

[0014]

[Function] If the reactor primary cooling system piping or the like connected to the reactor pressure vessel breaks, high-temperature and high-pressure reactor primary coolant is discharged to the drywell of the reactor containment vessel, and the drywell internal pressure / temperature is Rises sharply. The high-temperature and high-pressure reactor primary coolant discharged to this drywell is mixed with the atmosphere inside the drywell, is discharged into the pressure suppression pool water through the vent pipe, and is cooled from the reactor pressure vessel. Most of the energy released from the will be absorbed in the pressure suppression pool.

The pressure suppression pool water is injected into the reactor pressure vessel by the emergency core cooling system to cool the core, and in the long term, this injected water absorbs decay heat from the core and is dried from the fracture opening. It will continue to flow into the wells. As a result, the pressure and temperature inside the drywell will always remain higher than that in the pressure suppression chamber.Therefore, a pipe system with a discharge port shallower than the discharge opening water depth of the vent pipe should be installed from this drywell into the water of the pressure suppression pool. After installation, the flow from the drywell to the pressure suppression chamber will always pass through this piping system in the unlikely event of a reactor primary system breakage. Further, the middle of the piping is passed through another cooling pool water outside the containment vessel for cooling, and the long-term core decay heat is released to the outside of the containment vessel.
It is C.

Since this piping system functions as a vent pipe immediately after the accident, it suffices to secure a flow passage corresponding to the steam vapor amount due to long-term decay heat, and a large flow passage area is not required.

As described above, in the pressure suppression reactor containment vessel, if the piping system as described above which communicates from the drywell to the pressure suppression pool water is installed, the flow of the atmosphere from the drywell to the pressure suppression chamber is continuously performed. Paying attention to something, by arranging a catalytic hydrogen absorbing material in the middle of this piping system or in the suction part of the drywell, it will occur in the reactor containment vessel after the accident of a primary reactor piping breakage accident. The hydrogen gas can be effectively reduced.

Particularly in the case where the IC is arranged in the above-mentioned pipe, not only the pressure difference between the dry well and the pressure suppression chamber but also the water vapor in the fluid is condensed and decompressed by the IC, so that the dry well Although it has the effect of increasing the suction flow rate, by disposing the catalytic hydrogen absorbing material on the drywell side of the IC of the pipe of this IC configuration or on the drywell suction part, the differential pressure between the drywell and the pressure suppression chamber In addition to the generated flow, decompression is generated by the amount of absorption of hydrogen gas in the fluid, which has the effect of increasing the suction force of the drywell atmosphere. In addition, the IC cooling effect (vapor condensation effect)
It is generally known that the smaller the amount of non-condensable gas, the better the efficiency. Furthermore, the reaction when absorbing hydrogen with the catalytic hydrogen absorbing material has an exothermic action, and it is also possible to utilize the atmosphere rising force due to this, and this generated heat can be cooled by the IC, so heat is accumulated in the storage container. Can be effectively prevented (claim 1
Through 4).

The hydrogen gas generated in the reactor pressure vessel is transferred to the dry well and can be effectively reduced by the above-mentioned invention, but in the unlikely event that FP (nuclear row product) in the reactor is in the pressure suppression pool water. When released into the water, hydrogen and oxygen are generated in the pressure suppression pool water due to radiation water decomposition. These hydrogen
It is considered that oxygen migrates from the water surface of the pressure suppression pool to the space of the pressure suppression chamber, and the hydrogen gas concentration also rises in the pressure suppression chamber.

Under such a condition, the hydrogen gas concentration in the space of the pressure suppression chamber is reduced by the effect that the atmosphere acts as a catalytic hydrogen absorbing material against natural convection in the space due to the temperature rise of the pressure suppression pool water. It is important to arrange and configure such that they are in contact with each other (claim 7). However, the same thing can be said in the dry well, but immediately after the reactor primary system rupture, the projection force due to the jet force of the high temperature and high pressure fluid in the dry well and the pressure suppression chamber or the swell phenomenon of the pressure suppression pool water. Since a large load on the etc. is conceivable, it is necessary to arrange them on the wall surface or the like in a form with a low resistance for several minutes after the break (claims 7 to 11).

It is considered that the amount of hydrogen gas generated in the dry well is particularly remarkable, but since the reactor pressure vessel is hot, it is possible to expect sufficient running water in the atmosphere in the dry well due to natural convection. However, the drywell of the pressure suppression type containment vessel is small, and it is necessary to effectively utilize the limited space. As in the present invention, it is necessary to be able to install it on a lateral wall, a ceiling, etc., and also to be able to install the catalytic hydrogen absorber at an arbitrary angle along the direction of convection. The same applies to the pressure suppression chamber space (claim 7).

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS.

A reactor primary system piping 4 from a pressure vessel 3 having a reactor 1 and a reactor primary cooling water 2 inside penetrates an upper dry well 6 through an isolation valve 5. Pressure vessel 3
There is a lower dry well 7 below and is connected via a space on the side of the pressure vessel 3. Below the upper dry well 6, a diaphragm floor 8 is formed, and below that is a pressure suppression chamber space 10 having a pressure suppression pool 9. The upper dry well 6 and the pressure suppression pool 9 are communicated with each other by a vent pipe 11, and the pressure suppression pool 9 and the underwater opening 12 of the vent pipe 11 are opened horizontally in three stages. .. Above the upper dry well 6 is cooling water 1
2 and FIG. 3, a pipe 15 that extends into the pressure suppression pool 9 water is arranged. The water depth of the opening of the pipe 15 in the water of the pressure suppression pool 9 is set to be shallower than the water depth of the uppermost opening of the vent pipe opening 12.

In FIG. 4, a pipe 15 that penetrates the upper wall of the upper dry well 6 and extends in the cooling water 13 through the heat exchanger (isolation condenser: IC) 14 into the pressure suppression pool 9 is arranged. Has been done. This piping 1
The water depth of the opening of the pressure suppression pool 9 of 5 is set to be shallower than the water depth of the uppermost opening of the vent pipe opening 12.

The vent pipe inlet of FIG. 1 and the piping system 3 of FIG.
3, the hydrogen concentration reducer storage portion 34 outside the containment vessel in the piping system 33 in FIG. 3, and the dry well 6 in the piping 15 in FIG.
A hydrogen concentration reducer 32, that is, a catalytic hydrogen absorber having a structure shown in FIGS. 6 to 8 is installed in the opening and the wet well opening in FIG.

The structure of the catalytic hydrogen absorbing material will be described below with reference to FIGS. 6 to 8.

FIG. 6 shows a state of being housed on the ceiling surface, and the ceiling surface corresponds to the wall 16. When it is arranged on the side wall, it is convenient to deploy it by utilizing gravity so that it is accommodated in the side wall so that (A part) of FIG. 6 faces downward. The pipe 15 penetrates the wall 16 of the upper drywell 6 and is connected to the movable suction pipe 17 in the upper drywell 6 via a bearing 18 (shown in FIG. 8). Piping 1
5 and the connecting portion of the movable suction pipe 17 are shown in FIG. 6 and FIG. 7 showing a state in which the movable suction pipe 17 is opened in the atmosphere of the upper dry well 6 during operation.
As shown in FIG. 6, in either state of FIG. 6 or FIG. 7, the atmosphere in the upper dry well 6 can flow into the pipe 15. At this time, in the case of the state of FIG. 7, the inflow is possible only from the movable suction pipe 17.
A catalyst-type hydrogen absorption plate 19 formed in a plate shape or set in a plate shape is connected to the movable suction pipe 17 via a rotary shaft 20, and a supporting rod arranged substantially parallel to the movable suction pipe 17. 21 is connected to the catalytic hydrogen absorbing plate 19 via a rotary shaft 22. This support rod 21 is a wall 16
And a rotary shaft 23.

In the state of FIG. 6, all the catalytic hydrogen absorbing plates 18 of the bearing 18 and the rotating shafts 20, 22, 23 are superposed, and in the state of FIG. 7, all the catalytic hydrogen absorbing plates 1 are arranged.
9 are arranged so as to be substantially parallel to each other with a gap 24. The movable suction pipe 17 is provided with openings 25 in the same direction at intervals 24. The direction of this opening is set to face the upstream direction of the natural convection flow in the upper dry well.

A cover 26 is provided on the outer side (tip side) of the catalytic hydrogen absorbing plate 18 located at the tip of the movable suction pipe 17, and a lock mechanism 27 is provided on the side in contact with the wall surface 16 in the state of FIG. There is a hook 28. Lock mechanism 27
Is fixed to the wall surface 16 and can be unlocked by a control system (not shown). In addition, it is configured so that it can be manually locked or unlocked on-site for periodic inspections.

Further, the spring mechanism 31 enables unlocking and the catalytic hydrogen absorbing plate 19 mechanism after unlocking can be smoothly opened.

On the other hand, a discharge pipe 29 is installed from above the side wall in the pressure suppression chamber 10 shown in FIGS. 1 to 5 to the containment vessel vent system (not shown) via the isolation valve 30. The opening of the discharge pipe 29 in the pressure suppression chamber 10 has the same structure as that of FIGS. 6 to 8. However, in this case, the movable suction pipe 17 and the catalytic hydrogen absorbing plate 18 are arranged so as to be stored above the pipe 15 of FIG. 6 corresponding to the discharge pipe 29.

In this embodiment, when the work is carried out in the upper dry well of the containment vessel during a regular periodic inspection, etc., the workability is excellent in terms of space because it is stored in the manner of sticking to the wall surface as shown in FIG. ing. Figure 6 during normal plant operation
In this state, it is possible to prevent the performance of the catalytic hydrogen absorbing material from being deteriorated due to the adhesion of dust or oil dust in combination with the effect of the cover 26. Since a hook 28 for holding the catalytic hydrogen absorbing material on the wall surface is provided on the cover 26 by the lock mechanism 27, the catalytic hydrogen absorbing plate 19 and the movable suction pipe 17 are held on the wall surface. It also serves as a necessary strength member.

Should the reactor primary system piping 4 break,
The internal pressure of the upper dry well 6 and the lower dry well 7 rises due to the high-temperature, high-pressure water and steam released from the pressure vessel. Then, the water surface in the vent pipe 11 is pushed down so that the atmosphere of the dry wells 6 and 7 becomes the opening 1 of the vent pipe 11.
2 is discharged into the pressure suppression pool 9 water, water vapor is condensed, and the rest (non-condensable gas) is the pressure suppression chamber space 1
Move to 0 and increase the internal pressure. At this point in time, there is a jet flow of water or water vapor discharged from the breakage port in the upper dry well 6, so that the catalytic hydrogen absorbing plate 19 and its mechanism arranged in the upper dry well 6 avoid an excessive external force. From the point of view, it is preferable that it is attached to a wall or the like.
Also, in the pressure suppression chamber space 10, there is a phenomenon of rising of the pressure suppression pool 9 (pool swell) due to the sudden release of the drywell 6, 7 atmosphere from the opening 12 of the vent pipe 11, It is preferable that the catalytic hydrogen absorbing plate 19 and its mechanism arranged in the pressure suppression chamber space 10 are attached to a wall surface or the like in order to avoid a water surface collision load due to pool swell and a drag load due to rising water.

When the primary cooling water is continuously discharged from the breakage port,
The internal pressure of the pressure vessel 3 also decreases, and the behavior of the atmosphere in the dry wells 6 and 7, the pressure suppression pool 9, and the pressure suppression chamber space 10 also suppresses a drastic flow phenomenon and becomes a convection phenomenon due to natural circulation due to the altitude difference. And transition. From this point in time, the hydrogen gas concentration in the pressure vessel 3 and in the pressure suppression chamber space 10 gradually rises due to the radiolysis of water and the water-metal reaction in the core. Then, it is necessary to take measures to reduce the concentration of hydrogen gas or oxygen gas approximately one day after the occurrence of the fracture accident. Therefore, after the rupture accident occurs, the operator manually operates the lock mechanism 2 from the central control room by the control system.
It is also possible to cancel (operate) 7. However, from the standpoint of not annoying the operator, by detecting an increase in the internal pressure of the dry wells 6 and 7 or a decrease in the water level of the reactor primary cooling water 2 in the pressure vessel 3 (LOCA signal), the above-mentioned dry Wells 6 and 7 and pressure suppression chamber space 10
It is also effective from the viewpoint of reducing the burden on the operator and avoiding a human error by using a system in which the lock mechanism is automatically released after, for example, 10 minutes, when the extreme flow phenomenon in (3) is completed.

When the lock mechanism 27 is released, the rotary shaft 1
The movable suction pipe 17 rotates about the fulcrum 8 by gravity or spring force, and at the same time, by the action of the support rod 21, the catalytic hydrogen absorbing plate 19 has a gap 24 from the wall surface at an angle parallel to the wall surface (ceiling surface). It can be placed in multiple steps away from each other.

Normally, the atmosphere in the upper dry well 6 and the pressure suppression chamber space 10 circulates convectively along the wall surface or ceiling surface, so that the atmosphere is parallel to the wall surface or ceiling surface as shown in FIG. 7 or FIG. 8 of the present invention. Since the catalyst type hydrogen absorbing plates 19 are arranged in multiple stages so that the circulating flow is not prevented and the catalyst has a lot of contact with the atmosphere, it is possible to effectively absorb the hydrogen gas in the atmosphere. Is.

The flow of the atmosphere may not always be parallel to the wall surface or the ceiling surface depending on the shape of the wall or ceiling or the installation location of the present invention. In this case, the length of the support rod 21 may be adjusted. The catalytic hydrogen absorbing plate 19 can be adjusted to be parallel to the flow of the atmosphere. Further, it is possible to arrange the catalyst type hydrogen absorbing plate 19 such that the direction of the flow is changed or the flow is made to impinge on the catalytic hydrogen absorbing plate 19 at a constant angle without intentionally being parallel to the flow of the atmosphere.

Next, the effect after the lock mechanism 27 is released and the catalytic hydrogen absorbing plate 19 is opened to the upper dry well 6 and the pressure suppression chamber space 10 will be described.

At about 10 minutes after the rupture accident,
Air existing in the upper dry well 6 (mainly nitrogen gas)
Is almost pushed out to the pressure suppression chamber space 10 by the water / water vapor from the breakage opening. Then, since the reactor primary cooling water 2 evaporated by the decay heat of the core 1 is continuously discharged into the upper dry well 6 from the breakage port, the atmosphere in the upper dry well 6 which is almost water vapor is opened in the movable suction pipe 17. Pipe 25 from section 25
And is condensed at the IC 14 portion because it is cooled, and the inflow atmosphere is decompressed. This reduced pressure further contributes to the suction of the atmosphere from the upper dry well 6. After the depressurization, the pressure control chamber 9 finally moves to the pressure control pool 9 while maintaining the balance between the internal pressure of the pressure control chamber space 10 and the head pressure of water immersion into the pressure control pool water. IC14 at this time
The cooling efficiency due to is worse as the amount of non-condensable gas in the fluid in the pipe 15 is larger, which is a major cause of deterioration in the performance of the IC 14.

Therefore, the hydrogen gas newly and continuously generated in the upper dry well 6 as in the present invention is supplied to the pipe 1
It is very important for ensuring the performance of the IC 14 that it is effectively absorbed / reduced before it is sucked into the IC 5 or before flowing into the IC 14, and the present invention enables this.

In addition, by installing the catalytic hydrogen absorbing plate 19 mechanism of the present invention in the suction portion of the vent system discharge pipe 29 of the storage container of the pressure suppression chamber space 10, the atmosphere in the storage container should be released ( Even at the time of venting, the risk of explosion outside the containment vessel can be avoided.

Further, in addition to the effect of the IC 14 and the containment vessel vent system, the catalytic hydrogen absorbing plate 19 can be effectively arranged for natural convection in the dry wells 6 and 7 and the pressure suppression chamber space 10. The hydrogen gas concentration in the dry wells 6, 7 and the pressure suppression chamber space 10 can be efficiently reduced.

[0043]

According to the present invention, in the pressure suppression type containment vessel, the hydrogen gas generated in the containment vessel is effectively reduced by effectively utilizing the flow of the atmosphere in the space inside the containment vessel in the event of an accident. can do. Moreover, when applied to a piping system having an IC, the cooling effect rate by this IC can be further improved.

According to the second and third aspects, at the time of venting the atmosphere in the containment vessel, the danger of explosion due to hydrogen gas in the vent system and near the discharge can be avoided.

According to claims 4 to 7, natural convection in the containment vessel can be effectively utilized in the event of an accident, and the hydrogen gas concentration in the containment vessel can be effectively reduced.

According to claim 8, it is possible to provide a system capable of achieving all the effects of claims 1 to 7.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment in a pressure suppression reactor containment vessel according to the present invention.

FIG. 2 is a sectional view of a second embodiment in the pressure suppression reactor containment vessel according to the present invention.

FIG. 3 is a sectional view of a third embodiment in a pressure suppression reactor containment vessel according to the present invention.

FIG. 4 is a sectional view of a fourth embodiment of the pressure suppression reactor containment vessel according to the present invention.

FIG. 5 is a sectional view of a fifth embodiment in a pressure suppression reactor containment vessel according to the present invention.

FIG. 6 is an explanatory view showing an embodiment of a suction portion in a storage container according to the present invention in a lateral state in which the suction portion is stored so as to be stuck to a wall surface.

FIG. 7 is an explanatory view of a lateral state opened apart from the wall surface.

FIG. 8 is a view on arrow BB in FIG. 7.

[Explanation of symbols]

1 ... Reactor, 2 ... Reactor primary cooling water, 3 ... Pressure vessel, 4
... Reactor primary system piping, 5 ... isolation valve, 6 ... upper drywell, 7 ... lower drywell, 8 ... diaphragm floor, 9 ...
Pressure suppression pool, 10 ... pressure suppression chamber space, 11 ... vent pipe, 12 ... vent pipe underwater opening.

Claims (11)

[Claims] 1. A pressure suppression containment vessel having a dry well surrounding a pressure container having a hydrogen generation factor, a pressure suppression chamber having a pressure suppression pool, and a vent pipe communicating the pressure suppression pool with the dry well. A static combustible gas concentration control system, wherein a hydrogen gas concentration reducer is arranged in the vent pipe communicating from the dry well to the pressure suppression pool. 2. A pressure suppression type containment container having a dry well surrounding a pressure container having a hydrogen generation factor, a pressure suppression chamber having a pressure suppression pool, and a vent pipe communicating the pressure suppression pool with the dry well. A position where a piping system communicating from the dry well to the pressure suppression pool is installed, and an outlet position of the piping system communicating from the dry well to the pressure suppression pool is submerged in a position shallower than the vent pipe outlet position. A static combustible gas concentration control system, characterized in that a hydrogen gas concentration reducer is disposed in the pipe system communicating with the pressure suppression pool from the dry well. 3. The pipe system facility according to claim 2, wherein the pipe system communicating from the dry well to the pressure suppression pool is arranged outside a containment vessel, and the pipeline system is installed at an inlet of the pipe system or outside the containment vessel. Static flammable gas concentration control system with hydrogen gas concentration reducer. 4. A pressure suppression containment vessel having a dry well surrounding a pressure container having a hydrogen generation factor, a pressure suppression chamber having a pressure suppression pool, and a vent pipe communicating the pressure suppression pool with the dry well. In the pressure suppression containment vessel having a piping system for communicating with the pressure suppression pool or a separately installed cooling pool via a cooler installed separately from the vent pipe communicated from the drywell to the pressure suppression pool, A static combustible gas concentration control system, wherein a hydrogen gas concentration reducer is arranged in the drywell portion of the piping system, or particularly in the piping system having the cooler, in the piping system on the drywell side of the cooler. 5. A dry well surrounding a pressure container having a hydrogen generation factor, a pressure suppression chamber having a pressure suppression pool, and a vent pipe communicating the pressure suppression pool with the dry well are provided from the pressure suppression chamber space portion. In the pressure suppression type containment vessel having a vent system for extracting an atmosphere outside the pressure suppression type containment vessel, a hydrogen gas concentration reducer is arranged in a space of the pressure suppression chamber of the vent system. Static flammable gas concentration control system. 6. The method according to claim 1, 2, 3, 4 or 5.
A static combustible gas concentration control system using a catalytic hydrogen absorbing material in the hydrogen gas concentration reducer. 7. A catalyst-type hydrogen adsorbent installed in the containment vessel for suppressing the hydrogen gas concentration in the containment vessel, a support structure provided via a wall surface of the containment vessel or an alternative wall surface and a rotary shaft. An object, the support structure, and the catalyst-type hydrogen adsorbent formed in a plate shape via a rotary shaft, and the plate is formed when the support structure forms a certain angle with the wall surface. A static combustible gas concentration control system, characterized in that a catalytic hydrogen adsorbent formed in a shape is arranged in the atmosphere inside the containment vessel in parallel or at a predetermined angle with respect to the wall surface. 8. A support structure according to claim 7, wherein a second support structure is installed substantially parallel to the support structure installed via the rotary shaft with respect to the wall surface, and the second support structure is the wall surface. And a static combustible gas concentration control system connected to the plate-shaped catalytic hydrogen adsorbent through a rotating shaft. 9. The method according to claim 7 or 8, wherein when not in use, the plurality of catalytic hydrogen adsorbents formed in the plate shape are locked on the wall surface in an overlapping state, and unlocked manually or automatically. The support structure installed via the wall surface and the rotating shaft by its own weight or the force of a spring spreads to a certain angle with the wall surface, and at the same time, the plate-shaped catalytic hydrogen adsorbent is formed on the wall surface. Static flammable gas concentration control system configured to be parallel or at a predetermined angle. 10. The static combustible gas concentration control system according to claim 9, wherein the lock is released with a time delay of about 10 minutes after the drywell pressure high or pressure vessel water level low signal. 11. The catalyst type hydrogen adsorption device according to claim 1, 2, 3, 4, 5 or 6, wherein the hydrogen gas concentration reducer has the structure according to any one of claims 7 to 10. Atmosphere of the dry well or pressure suppression chamber space flowing near the material, in the opening of the dry well or pressure suppression chamber space of the static combustible gas concentration control system after contact with the catalytic hydrogen adsorbent Static flammable gas concentration control system configured to be guided.