JP3402915B2 - Combustible gas concentration control device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nuclear power generation facility in which an accident such as loss of reactor coolant material occurs.
When hydrogen generated by radiolysis of water or reaction between fuel cladding and water fills the reactor containment vessel, it is possible to control the flammable gas concentration control device so that hydrogen does not exceed the flammable limit concentration ( Hereinafter, referred to as an FCS device) and a reactor containment vessel equipped with this FCS device.

[0002]

2. Description of the Related Art Generally, in a conventional boiling water nuclear power plant, a reactor pressure vessel for accommodating a core is accommodated in a reactor containment vessel made of steel or reinforced concrete. Further, an FCS device for safely processing hydrogen, which is a combustible gas generated in the event of a loss of cooling water, is provided outside the reactor containment vessel. Hereinafter, a conventional reactor containment vessel, a hydrogen generation mechanism at the time of a loss of coolant accident, and a conventional FCS device will be described with reference to FIG.

The reactor containment vessel 1 in a nuclear power plant is an important structure for accommodating a reactor pressure vessel 80 that accommodates a core 91. The reactor containment vessel 1 is mainly composed of an upper dry well 2, a lower dry well 3 and a suppression pool 4, and the suppression pool 4 has a suppression pool gas phase portion 41. The upper dry well 2, the lower dry well 3, and the suppression pool 4 are connected to each other via a connecting pipe 40a.

The suppression pool 4 serves to reduce the pressure increase caused by the steam or other condensable gas generated in the reactor containment vessel 1 by condensation. Further, a drywell spray pipe 95 is provided in the upper part of the reactor containment vessel 1, and cooling is performed from the spray nozzle 96 so that the pressure in the reactor containment vessel 1 is not excessively increased by the steam generated at the time of the loss of coolant. By releasing water, the pressure is reduced by condensation.

In addition, in the suppression pool 4, there is provided a tunnel called an access tunnel 97 from the outside of the reactor containment vessel 1 to the lower drywell 3, and during the periodic inspection, equipment is carried in and out and workers are passed. Is used for.

In the loss of coolant accident, the piping 92 constituting the system in the reactor containment vessel 1 is broken for some reason, and the coolant (water) of the reactor, that is, the reactor water 94 is discharged from the broken portion 93. The reactor water 94 in the reactor pressure vessel 80 is reduced and caused.

At the time of this loss of coolant accident, not only the generation of water vapor but also the core 91 housed in the reactor pressure vessel 80.
(Combustible gas) produced by the reaction of zirconium, which is the material of the fuel rod cladding tube, and the steamed reactor water 94
Occurs and is released into the reactor containment vessel 1 from the breakage portion 93 that causes the loss of the coolant. Further, since water is used as the coolant, water is decomposed by radiation from the radioactivity contained in the reactor water 94 at the time of an accident, and hydrogen and oxygen are generated.

Hydrogen and oxygen produced by radiolysis of this water are
It is generated in the lower dry well 3 and the suppression pool 4 via the portion into which the reactor water 94 flowing out from the breakage portion 93 flows, that is, the upper dry well 2 in the reactor containment vessel 1.

When these hydrogen and oxygen are accumulated in the reactor containment vessel 1 and the hydrogen / oxygen concentration exceeds the explosive limit value for forming a flammable atmosphere, that is, 4 vol% of hydrogen and 5 vol% of oxygen, hydrogen and oxygen are separated. The recombination reaction of may occur. When the hydrogen / oxygen recombination reaction occurs, heat and pressure generated at that time may impair the soundness of the reactor containment vessel 1.

Therefore, the FCS device 90 takes out and heats the gas body in the reactor containment vessel 1 so that the inside of the reactor containment vessel 1 does not become a flammable atmosphere after the coolant loss accident, and is contained in the gas body. By chemically combining hydrogen and oxygen and converting them into steam or water, the concentration of hydrogen and oxygen contained in the atmosphere inside the reactor containment vessel 1 is lowered.

The FCS device 90, as shown in FIG.
A transfer pipe 82 for extracting and transferring a gas body in the dry well 81 of the nuclear reactor containment vessel 1, a blower 83 as a drive source for transferring the gas body, and a heating pipe 8 for heating the gas body.
4, a reactor 85 for combining hydrogen, which is a combustible gas contained in a gas body, with oxygen, a cooler 86 for cooling the processing gas discharged from the reactor 85, and a secondary side of the cooler 86. The steam / water separator 87 is provided, and the reflux pipe 88 for returning the processing gas from the steam / water separator 87 to the suppression pool gas phase portion 41.

Here, the blower 83, the heating pipe 84, the reactor 85, the cooler 86, the steam separator 87, and the flow rate adjusting valve 89.
Are assembled in a package in a single device frame to form the FCS device 90.

The FCS device 90 has electrical components and the like, and is installed outside the reactor containment vessel because the environmental conditions of the installation place are limited. Therefore, a place for this and a power source for a heating pipe, a blower and the like are required, which is a large facility.

On the other hand, on the other hand, F which does not require a power source
An FCS device using a catalyst has been developed as a CS device. An example of this FCS device is shown in FIG. Although there are FCS devices shown in FIGS. 16 (a) and 16 (b) depending on the shape of the catalyst, the configuration and the operating principle are the same in both examples as described below. FCS
The apparatus has a casing 71 and a cartridge 73 containing a catalyst 72 in which a catalyst such as platinum or palladium is supported on alumina. Gas inlet 7 at the bottom of casing 1
Hydrogen contained in the gas introduced from No. 4 combines with oxygen by the action of the catalyst, and the reaction heat at that time heats the catalyst and the surrounding gas. The gas having a high temperature is discharged from the discharge port 75, including water vapor which is a reaction product of hydrogen and oxygen. Such an FCS device is installed in the reactor containment vessel to reduce the hydrogen gas concentration in the reactor containment vessel. It should be noted that in FIG. 16A, the cartridge 73 is configured to fit into the lower portion of the casing 71 in a drawer shape.

Further, although the FCS device shown in FIG. 16 has a different structure, such an FCS device is also disclosed in Japanese Patent Laid-Open No. 5-203778. The FCS device described in this publication effectively utilizes the flow of the atmosphere in the space inside the containment vessel in the event of an accident.

[0016]

DISCLOSURE OF THE INVENTION In the reactor containment vessel having the FCS device using the above-mentioned conventional catalyst, the reacted gas is discharged at a high temperature, so that the gas circulation in the reactor containment vessel If the flow is not properly formed, the reacted gas may accumulate in the upper part of the reactor containment vessel and stratify. When the amount of treated gas increases and reaches the inlet of the catalytic FCS unit, the catalyst
There is also a possibility that the recombination reaction due to will be stopped and stopped, and unprocessed hydrogen gas will remain in the lower part of the reactor containment vessel.

Further, the FCS device disclosed in Japanese Patent Laid-Open No. 5-203778 also discloses a device for absorbing hydrogen by utilizing natural convection by a heat source centering on a reactor pressure vessel, but the FCS device. This is not used in consideration of the heat generated by itself.

[0018]

Therefore, an object of the present invention is to efficiently utilize the heat generated by the FCS device itself, avoid generation of a portion in which hydrogen gas having a high concentration remains in the reactor containment vessel, and to achieve a higher safety margin. To provide an FCS device that secures the

[0020]

In order to achieve the above object, in the reactor containment vessel of the present invention, in the invention according to claim 1, an opening for sucking hydrogen and oxygen and the hydrogen and oxygen are reused. In a combustible gas concentration control device having a release part for accommodating a catalyst to be combined and discharging the processing gas after recombining, a plurality of the openings are provided in a vertical direction and a movable joint
The lid that can be opened and closed with your hands and the end of this lid
A tension part that fixes the part and opens the lid part by tension.
And is provided in the middle of this tension part and melts at a predetermined temperature
And a metal part .

A combustible gas concentration controller according to a second aspect of the present invention is the combustible gas concentration controller according to the first aspect,
Within 1m from the diaphragm floor inside the reactor containment vessel
It was high and was installed on the inner wall of the reactor containment vessel.
Of.

[0022]

[0023]

[0024]

[0025]

[0026]

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION A first embodiment (corresponding to claim 1 ) of an FCS device according to the present invention will be described below with reference to FIG. The inlet pipe 60 of the FCS device 6 has a plurality of openings 61a and 61b. A lid 62 is attached to the openings 61a and 61b via a movable joint 63, and is supported in an open state by a wire 65 connected by a molten metal 64. As a result of the operation of the FCS device 6, when a high-temperature gas with a low hydrogen concentration is discharged from the discharge port 5, if the surrounding gas is not sufficiently agitated and mixed, the gas is stratified and the gas is stratified from above the dry well or suppression pool. Gradually stays downward.

However, when the high temperature gas reaches the vicinity of the uppermost opening 61a, the molten metal 64a melts because of the high temperature and the lid 62a falls by its own weight to close the opening 61a. As a result, even when the FCS device 6 is surrounded by the stratified gas that has been treated, the opening 61a in that portion is formed.
Is automatically closed, so the opening 61b below it is
It is possible to take in gas from and continue the hydrogen treatment.

By thus providing a plurality of openings 61a and 61b to prevent the re-intake of the stratified gas having a low hydrogen concentration at a high temperature, it is possible to prevent the gas from being re-inhaled. In 6, it is possible to process hydrogen gas having a higher concentration.

Next, a reference example of the FCS device according to the present invention will be described with reference to FIG. In this reference example , FCS
The device 6 has an inlet pipe 13 and is provided with a plurality of openings 14 in the inlet pipe 13.

In the opening 14, a plate-like member 17 and a float 18 which can rotate around a shaft 22 provided in the upper portion of the opening 14 are connected by a wire-like member 19 through a pulley 20. The plate member 1 is provided between the plate member 17 and the inlet pipe 13.
An elastic body 2 for exerting a force in the opening direction on 7, namely a repulsive force
It has a structure in which 1 is placed.

In this embodiment, the inlet pipe 1 of the FCS device 6 is used.
No. 3 is installed in the water of the suppression pool or in the lower dry well where the coolant may be stored.

When the water level in the space in which the FCS device such as the lower drywell and the suppression pool is placed rises, the float 18 floats to relax the force applied to the elastic body 21, and the plate member 17 is lifted upward. Opening 1
4 opens.

When the water level further rises, the opened opening 14 is submerged in water, but in that case, the opening 14 above it is opened. According to this structure, the opening 14 near the water surface among the plurality of openings 14 opens, and the opening 14 of the inlet pipe 13 above the opening 14 has the weight of the float 18 downward from the wire-shaped member 19. It is sealed by the plate member 17 for pulling. Further, the opening 14 below the opening 14 is submerged and is sealed with water. Therefore, considering the case where the water level of the lower drywell and suppression pool is increased by providing this inlet pipe 13 at the intake 12 of the FCS device 6, the FCS device 6 is higher than the lower drywell, floor of the suppression pool, or the water surface. Even when installed in a position, it is possible to efficiently suck in hydrogen gas generated from a place near the water surface.

In the present embodiment, it is possible to provide the FCS device capable of efficiently processing the hydrogen gas even when the water level in the suppression pool or the lower dry well is increased.

Next, a second embodiment (corresponding to claim 4) of the FCS device according to the present invention will be described with reference to FIGS. 3 and 4. It is desirable that the treated gas discharged from the discharge port of the FCS device be mixed homogeneously with the surrounding atmosphere.
The FCS device 6 is installed at a low position in the upper dry well 2, the lower dry well 3, and the suppression pool 4 in order to efficiently use the mixing effect that can be expected while the high-temperature treated gas rises in the space. It is considered preferable to do this.

In this embodiment, it is arranged on the wall surface in the upper dry well 2 of the reactor containment vessel 1 within 1 m of the diaphragm floor 7. This installation height is based on the result of obtaining the inlet flow velocity when the hydrogen treatment capacity of the FCS apparatus using the catalyst is atmospheric pressure and 4% hydrogen atmosphere. Specifically, for example, the FCS shown in FIG.
Since the maximum is about 4.3 kg / h in the device and about 2.5 kg / h in the FCS device in Fig. 14 (b), the distance from the gas inlet is used as a variable and the inlet flow velocity is calculated to correspond to the distance from the gas inlet. The flow rate of the suction gas flow is as shown in FIG. It can be seen from FIG. 4 that the flow velocity of the gas toward the inlet decreases as the distance from the gas inlet increases. Therefore, in order to effectively take in the gas near the diaphragm floor 7, it is necessary to consider the installation location of the FCS device 6 so that the suction gas flow rate near the diaphragm floor 7 does not extremely decrease. The installation height is determined within 1m.

In FIG. 3, the FCS device 6 can be installed by fixing it to the wall surface with anchor bolts 30 or by suspending it from a support member 31. By installing the FCS device 6 within 1 m from the diaphragm floor 7, the gas flow in the upper dry well 2 is
A natural convection indicated by an arrow 32 is generated by the heat generated by itself, and a flow that mixes the atmosphere is formed in the upper dry well 2.

In the present embodiment, particularly by using the FCS apparatus described in claim 1, natural convection can be expected to occur even when stratification by the high temperature treated gas occurs. It goes without saying that it is possible to improve the processing capacity of hydrogen gas.

Further, the FCS device according to the present inventionReference example
Will be described with reference to FIG. BookReference exampleIn the sub
It is arranged in the recession pool 4,Reference exampleTo
Also, as in the embodiment of FIG. 3, the FCS device is on the water surface.
Nori is also located within 1m.

Next, a reference example of the FCS device according to the present invention will be described with reference to FIGS. 6 and 7. FIG. 7 is a sectional view taken along the line AA shown in FIG. In this reference example , the FCS device 6 is installed with an attachment jig 9 on the outer surface of an access tunnel 8 connecting the lower dry well 3 and the outside of the reactor containment vessel 1. In FIG. 7, a plurality of FCS devices are installed with their backs aligned. This installation enables the FCS device 6 to be arranged near the water surface of the suppression pool 4.

In the fourth embodiment, it is installed only on the wall surface of the suppression pool 4, but according to the present embodiment, since it is installed in the access tunnel 8, hydrogen gas is also provided near the center of the suppression pool 4. Can be processed.

A reference example of the FCS device according to the present invention will be described with reference to FIGS. 8 and 9. In the present reference example , the connecting pipe opening 40 provided in the diaphragm floor 7 is located at the upper end of the connecting pipe 40a that connects the upper dry well 2 and the suppression pool 4 in the reactor containment vessel 1. It is installed within 1m. Suppression pool water is one of the hydrogen gas generation sources at the time of an accident. In this case, however, hydrogen is accumulated in the suppression pool gas phase part 41 due to hydrogen generation from the water held in the suppression pool 4 (suppression pool water). , The pressure increases. Therefore, a check valve 42 is provided to release the pressure to the drywell side, and the hydrogen gas 43 in the suppression pool gas phase portion 41 enters the connecting pipe through the check valve 42 and goes to the upper drywell 2 side. Moving. Therefore, FC is provided in the vicinity of the connecting pipe opening 40, which is a hydrogen gas discharge port.
If the S device 6 is installed, hydrogen gas can be effectively treated.

As the installation form, the one shown in FIGS. 3 and 5 mounted on a wall is described, but an example of installation on the floor is shown in FIG. This is composed of the FCS device 6 and the support legs 11, and is installed on the diaphragm floor 7 of the upper dry well 2. In this embodiment, the gas flow 32 is generated from between the support legs 11 toward the gas inlet 74.

Next, a reference example of the FCS device according to the present invention will be described with reference to FIG. In FIG. 10, the lower dry well 3 can also be installed on the floor surface of the lower dry well 3 (within 1 m from the floor) as shown in FIGS. 3 and 5. However, if the water level in the suppression pool 4 rises in the event of an accident, or if cooling water such as reactor coolant (reactor water) or drywell spray water flows into the upper drywell 2, the water will flow through the return line opening 10 to the lower drywater. Since it may flow into the well 3, F
If the CS device is placed near the floor, it may be submerged.

Therefore, in the plant having the lower D / W as in this case, the possibility can be reduced by disposing the FCS device 6 above the return line opening 10 and as low as possible. However, in this embodiment, natural convection due to the heat generated by the FCS device 6 itself is possible only at the upper part of the return line opening 10.
In a situation where coolant or the like flows in through the return line opening 10, even if installed above the floor surface, the FCS
It is likely that the device 6 will be overwhelmed with coolant and it may be desirable to install it above the return line opening 10.

Next, a reference example of the FCS device according to the present invention will be described with reference to FIG. Reference explained using FIG.
As described in the example , water for cooling the reactor and the reactor containment vessel may flow into the reactor containment vessel 1, especially in the lower dry well 3 and the suppression pool 4 in the event of a reactor accident. Therefore, it is better to install the FCS device 6 at a higher position in the lower dry well 3 and the suppression pool 4 in consideration of this inflow water. However, F
It is advantageous to provide the intake port of the CS device 6 at a low space for the reason described with reference to FIGS. 3 and 4. This is a reference example for simultaneously solving these conflicting requirements.

In the present embodiment, as shown in FIG. 11, the FCS device 6 installed in the lower dry well 3 or the suppression pool 4 in the reactor containment vessel 1, and from the intake 12 of the FCS device 6 downward. The installed inlet pipe 13 and a plurality of openings 1 provided on the inlet pipe
It consists of 4. The water level gradually rises due to the water flowing into the lower dry well 3 and the suppression pool 4 at the time of the accident.

Here, the FCS device 6 is installed at a high position of the lower dry well 3 or the suppression pool 4 in order to escape submersion in water, but the atmosphere gas containing hydrogen at the lower position of the lower dry well 3 or the suppression pool 4 is FC from the opening 14 provided in the inlet pipe 13
It is configured to be sucked into the S device 6.

In this embodiment having such a structure, even if the opening 14 below the inlet pipe 13 is submerged in water, hydrogen gas is sucked from the upper opening to process the hydrogen gas. You can In particular, the FCS device 6 provided in the lower dry well 3 is not covered with inflow water. Moreover, since the water level rises as the amount of inflowing water increases, it is possible to inhale a large amount of generated hydrogen and improve the efficiency.

Further, by providing the FCS apparatus according to the first aspect, even if the stratification of the high temperature gas occurs, the hydrogen gas treatment can be performed with higher efficiency. A reference example of the FCS device according to the present invention will be described with reference to FIGS. 12 and 13. The FCS device 6 is installed along the wall surface of the upper part of the upper dry well 2 and the upper part of the suppression pool 4, or is installed on the side or below the reactor containment vessel spray 45 by being suspended by a support. The hot gas 46 after the hydrogen / oxygen reaction is discharged horizontally or upward as shown in FIG. At this time, since the reactor containment vessel spray 45 is operating, as shown in FIG.
An entrained flow 48 of the atmospheric gas is generated along the circumference. Therefore, the exhaust gas of the FCS device 6 can be combined with the entrained flow 48, and at the same time, the treated gas is uniformly mixed in the reactor containment vessel, and the reacted gas is cooled by the spray water. It

Here, the detailed installation location of the FCS device 6 will be described with reference to FIG. The reactor containment vessel spray 45 shown in FIG. 12 has a spray pipe 101, a nozzle body 102, and a nozzle tip 1 as shown in FIG.
03a, b. Nozzle tip 103a, 10
A plurality of 3b are mounted on the nozzle body 102 and spray water can be sprayed over a wide range. Nozzle body 102
The spray pipe 101 to which is attached is configured in an annular shape, and is suspended by a support from the ceiling of the upper dry well and the suppression pool. The direction of the nozzle body may be vertically downward, the one facing the outside of the reactor containment vessel, the one facing the center direction of the reactor containment vessel, and the direction of the water sprinkled by the reactor containment vessel spray 45. Can be arbitrarily determined.

Nozzle tip 10 covers the spraying range of spray water.
It is determined as the sum of the watering ranges of 3a and 103b. The limit line of the watering range is determined to be a predetermined range depending on the width of the reactor containment vessel 1 or the cooling capacity of the reactor containment vessel spray 45. When the installation location of the FCS device 6 is within the water spray limit line 104, the catalyst stored in the FCS device 6 may get wet with water, which may adversely affect the performance such as the starting characteristic. Therefore, it is installed outside the water spray limit line 104 as shown in FIG. 13 and in the vicinity of the water spray limit line 104.

According to the FCS device 6 thus installed, the catalyst contained in the FCS device 6 does not get wet with water, and the entrainment flow 48 due to the operation of the reactor containment spray 45 is utilized. Thus, the hydrogen gas processing capacity can be improved.

A reference example of the FCS device according to the present invention is shown in FIG.
It will be explained based on. In this reference example , the casing 51 (indicated by reference numeral 71 in FIG. 16) of the FCS device 6 is mounted between the wall surfaces 50 of the reactor containment vessel by the mounting bolts 52 via the shielding member 15 having a small thermal conductivity. Therefore, the radiant heat generated by the casing 51 of the FCS device 6 can be prevented from being transmitted to the wall surface 50 of the reactor containment vessel. The heat shield member 15 is fixed to the mounting bolt 52 by a nut 53 and a washer 54.

Further, in order to prevent the heat of the FCS device 6 from being transferred to the wall surface 50 of the reactor containment vessel through the mounting bolts 52, the heat shield ring 16 formed of a substance having a small thermal conductivity such as ceramics is provided with the nut 55. And washer 5
By inserting the casing 51 with 6, the casing 51
Support. The mounting bolts 52 are connected to the wall surface 50 of the containment vessel by welding. The heat shielding ring 16 can prevent heat from being transferred between the high temperature casing 51 and the mounting bolt 52, so that the mounting bolt 52 can be prevented from reaching a high temperature.

[0057]

As described above, in the FCS device of the present invention, a plurality of openings are provided and the effective openings are selected.
Since it is possible to inhale highly concentrated hydrogen gas,
Higher concentration in FCS equipment with
It is possible to efficiently process the hydrogen gas, and to avoid generation of a portion where the hydrogen gas having a high concentration remains in the reactor containment vessel, thereby ensuring a higher safety margin.

[0058]

[Brief description of drawings]

FIG. 1 is an external view showing a first embodiment of a combustible gas concentration control device according to the present invention.

FIG. 2 is an external view showing a reference example of a combustible gas concentration control device according to the present invention.

FIG. 3 is an external view showing a second embodiment of a combustible gas concentration control device according to the present invention.

FIG. 4 is a characteristic diagram showing a relationship between a distance from a gas inlet and an intake flow velocity in a combustible gas concentration control device using a catalyst.

FIG. 5 is a longitudinal sectional view showing a reference example of a combustible gas concentration control device according to the present invention.

FIG. 6 is a longitudinal sectional view showing a reference example of a combustible gas concentration control device according to the present invention.

7 is a cross-sectional view taken along the line AA shown in FIG.

FIG. 8 is a longitudinal sectional view showing a reference example of a combustible gas concentration control device according to the present invention.

FIG. 9 is an external view showing a reference example of a combustible gas concentration control device according to the present invention.

FIG. 10 is a reference of the combustible gas concentration control device according to the present invention.
The longitudinal cross-sectional view showing an example .

FIG. 11 is a reference of the combustible gas concentration control device according to the present invention.
The longitudinal cross-sectional view showing an example .

FIG. 12: Reference of flammable gas concentration control device according to the present invention
The longitudinal cross-sectional view showing an example .

FIG. 13 is a reference of the combustible gas concentration control device according to the present invention.
In the example , a conceptual diagram for explaining the watering limit line of the reactor containment vessel spray.

FIG. 14 is a reference of the combustible gas concentration control device according to the present invention.
The longitudinal cross-sectional view showing an example .

FIG. 15 is a system configuration diagram showing a conventional example of a combustible gas concentration control device.

16 (a) and 16 (b) are outline views each showing a conventional example of a combustible gas concentration control device with a part thereof cut away.

[Explanation of symbols]

1 ... Reactor containment vessel 2 ...
Upper dry well 3 ... Lower dry well 4 ...
Suppression pool 6 ... Static flammable gas control device 7 ...
Diaphragm floor 8 ... Access tunnel 9 ...
Mounting jig 10 ... Return line opening 11 ...
Support legs 12 ... Intake 13 ...
Inlet pipe 14 ... Opening 15 ...
Heat shield member 16 ... Heat shield ring 17 ...
Plate member 18 ... Float 19 ...
Wire-shaped member 20 ... Pulley 21 ...
Elastic body 22 ... Shaft 30 ...
Anchor bolt 31 ... Supporting member 32 ...
Gas flow 40 ... Communication pipe opening 40a ...
Communication pipe 41 ... Suppression pool gas phase part 42 ... Check valve 43 ... Hydrogen gas 45 ...
Reactor containment vessel spray 46 ... High temperature gas 47 ...
Spray flow 48 ... Entrainment flow 50 ...
Wall of reactor containment vessel 53 ... Nut 54 ...
Washer 55 ... Nut 56 ...
Washer 60 ... Inlet pipe 61a, 61b ...
Opening 62 ... Lid 63 ...
Movable joint 64 ... Molten metal 65 ...
Wire 71 ... Casing 72 ...
Catalyst 73 ... Cartridge 74 ...
Gas inlet 75 ... Outlet 81 ...
Drywell 82 ... Transfer piping 83 ...
Blower 84 ... Heating tube 85 ...
Reactor 86 ... Cooler 87 ...
Steam separator 87 ... Steam separator 88 ...
Reflux pipe 89 ... Flow control valve 90 ...
FCS device 91 ... Reactor core 101 ...
Spray pipe 102 ... Nozzle bodies 103a, 103b ... Nozzle tip 104 ... Sprinkling limit line

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Claims (2)

(57) [Claims] 1. A flammable gas concentration control device comprising: an opening for sucking hydrogen and oxygen; and a discharge portion for accommodating a catalyst for recombining hydrogen and oxygen, and for discharging a processing gas after recombination. A plurality of the openings are provided in the vertical direction and the movable joint is
The lid that can be opened and closed with your hands and the end of this lid
A tension part that fixes the part and opens the lid part by tension.
And is provided in the middle of this tension part and melts at a predetermined temperature
A combustible gas concentration control device comprising a metal part . 2. The flammable gas concentration control device is installed on an inner wall surface of the reactor containment vessel at a height within 1 m from a diaphragm floor in the reactor containment vessel. 1. The flammable gas concentration control device according to 1.