KR20230170174A - Hydrogen depletion system in nuclear facilities - Google Patents

Abstract

The present invention relates to a hydrogen abatement system for nuclear power plants. The hydrogen abatement system for nuclear power plants according to the present invention includes a housing formed with an inlet through which air flows in and an outlet through which air is discharged, and the inside of the housing being coated so that the incoming air is included. A passive catalytic hydrogen recombiner including a catalyst that removes hydrogen by inducing a chemical reaction with hydrogen, and a thermoelectric generator that generates electricity using heat generated by the catalytic reaction in the passive catalytic hydrogen recombiner, and is supplied with power from an external source. It is characterized by reducing hydrogen without supply.

Description

Hydrogen abatement system in nuclear facilities {HYDROGEN DEPLETION SYSTEM IN NUCLEAR FACILITIES}

The present invention relates to a hydrogen reduction system in nuclear facilities. More specifically, when a serious accident occurs in a nuclear facility such as a nuclear power plant, even if there is no external power source, electricity is produced using an internal system and hydrogen is actively produced using this. This relates to a hydrogen reduction system for nuclear power plants that reduces hydrogen to prevent hydrogen explosion.

When a serious accident occurs in a nuclear power plant's reactor, hydrogen can be generated for a variety of reasons, and this hydrogen can proceed into an explosive reaction even at a small concentration, so a means to lower the hydrogen concentration in advance is needed. If these means do not operate properly and the hydrogen concentration in the containment vessel exceeds 10%, the hydrogen may explode simply by applying a small amount of energy, resulting in damage to the containment building and large-scale leakage of radioactive materials. A similar situation occurred in the Fukushima nuclear power plant accident in Japan in 2011, resulting in a large amount of radioactive material leaking.

Nuclear power plants are equipped with hydrogen ignitors or passive autocatalytic recombiners (PAR) to prevent hydrogen explosions that may occur inside the containment vessel in the event of a serious accident.

A hydrogen igniter is a device that burns hydrogen little by little and turns it into water. Hydrogen can be burned when the hydrogen concentration is more than 5%. At this time, an external power source is required to operate the hydrogen igniter. When power is lost due to a serious accident at a nuclear power plant, power must generally be supplied from an emergency diesel generator. Hydrogen igniter has very high hydrogen removal performance because it uses an external power source, but it has the problem of not being able to operate in the event of an accident such as the Fukushima accident where the external power source is completely lost.

PAR is a highly reliable device because it consists only of driven devices that do not require external power and can operate without power or other support systems. Oxygen and hydrogen generally recombine through rapid combustion at temperatures above 593℃, but catalytic combustion occurs at temperatures lower than 0℃ by catalytic materials such as palladium or platinum, and oxygen and hydrogen atoms or Adsorption occurs due to the attractive force between molecules. This reaction between hydrogen and oxygen on the catalyst surface can be used to prevent the hydrogen concentration from increasing.

PAR allows air to flow from the outside to the inside through circulation caused by natural convection, and for this purpose, it is formed in the shape of a metal box that allows air to pass from the bottom to the top. In order to maintain a continuous catalytic reaction, the reaction heat generated from the surface of the catalyst metal installed at the bottom must increase the gas temperature to cause a circulation effect by natural convection, which requires a large volume and height.

Therefore, although the reliability of the PAR device is high, the size of the device is large and there is a problem that multiple devices must be provided in the containment container. Figure 1 shows the location of PAR within the containment vessel of a nuclear power plant. As shown, PAR is installed at multiple locations within the containment vessel of a nuclear power plant to reduce hydrogen in the event of an accident.

Republic of Korea Patent Publication No. 10-2016-0049454

Therefore, the purpose of the present invention is to solve such conventional problems, by converting the heat generated by the catalytic reaction inside the driven catalytic hydrogen combiner into electricity through a thermoelectric generator (TEG) and using it to external By allowing electricity to be used even without a power supply, the aim is to provide a hydrogen reduction system for nuclear power plants that can improve the reliability of the hydrogen reduction device, improve hydrogen removal performance, and miniaturize the device.

The problems to be solved by the present invention are not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the description below.

The above object includes, according to the present invention, a housing formed with an inlet through which air flows in and an outlet through which air is discharged, and a catalyst coated on the inside of the housing to induce a chemical reaction with hydrogen contained in the introduced air to remove hydrogen. A passive catalyst type hydrogen material combiner; and a thermoelectric generator that generates electricity using heat generated by the catalyst reaction in the passive catalytic hydrogen recombiner, and reduces hydrogen without supplying power from the outside. This can be achieved by a hydrogen reduction system for nuclear power plants. there is.

Here, it further includes a fan that induces air supply within the housing, and the fan can operate using electricity generated from the thermoelectric generator.

Here, a heat pipe disposed between the passive catalytic hydrogen material combiner and the thermoelectric generator may further include a heat pipe that transfers heat generated by a catalytic reaction of the passive catalytic hydrogen material combiner to the thermoelectric generator.

Here, it further includes a hydrogen igniter that removes hydrogen from the air by burning hydrogen, and the hydrogen igniter can operate using electricity generated from the thermoelectric generator.

Here, the hydrogen igniter may be formed on the outer surface of the housing.

Here, a hydrogen concentration sensor that measures the concentration of hydrogen in the air; And a control unit that receives the hydrogen concentration in the air measured from the hydrogen concentration measuring sensor and controls the operation of the hydrogen igniter, wherein the control unit receives the hydrogen concentration in the air input from the hydrogen concentration measuring sensor when the hydrogen concentration in the air exceeds a threshold value. When doing so, the hydrogen igniter can be operated.

Here, it further includes a hydrogen igniter that removes hydrogen from the air by burning hydrogen, and the hydrogen igniter can operate using electricity generated from the thermoelectric generator.

Here, a hydrogen concentration sensor that measures the concentration of hydrogen in the air; And it may further include a control unit that receives the hydrogen concentration in the air measured from the hydrogen concentration measurement sensor and controls the operation of the fan.

Here, a temperature measuring sensor that measures the temperature around the catalyst; and a control unit that receives the temperature measured from the temperature measurement sensor and controls operation of the fan, wherein the control unit operates the fan to maintain the temperature of the air received from the temperature measurement sensor below a set threshold. You can do it.

Here, a capacitor that stores electricity generated by the thermoelectric generator may be further included.

According to the hydrogen reduction system for nuclear power plants of the present invention as described above, the heat generated by the catalytic reaction inside the passive catalytic hydrogen recombiner is converted into electricity through a thermoelectric generator and used to reduce hydrogen in nuclear power plants without supplying external power. The advantage is that the system can be operated, ensuring the reliability of the device even if external power is completely lost in a serious accident.

In addition, electricity generated from the thermoelectric generator can be used to operate a fan to supply air to the driven catalytic hydrogen combiner, thereby increasing hydrogen reduction efficiency compared to circulation by natural convection, and miniaturizing the size of the driven catalytic hydrogen combiner. There is also the advantage of being able to do it.

In addition, there is an advantage that hydrogen can be removed by operating a hydrogen igniter using electricity generated from a thermoelectric generator as well as a passive catalytic hydrogen combiner, thereby improving hydrogen removal performance.

In addition, the heat generated by the catalyst reaction inside the passive catalytic hydrogen combiner is converted into electricity through a thermoelectric generator and removed to passively control the temperature of the surrounding gas so that it does not rise above the natural ignition temperature of the catalyst. It also has the advantage of improving stability compared to a catalytic hydrogen recombiner.

In addition, there is an advantage that an optimal hydrogen concentration control method can be established by constructing an intelligent system by operating a fan or hydrogen igniter according to the hydrogen concentration measured by the sensor.

Figure 1 shows the location of PAR within the containment vessel of a nuclear power plant.
Figure 2 is a plan view of a hydrogen reduction system for a nuclear power plant according to an embodiment of the present invention.
Figure 3 is a cross-sectional view taken in the direction a of Figure 2.
FIG. 4 is a cross-sectional view taken in the b direction of FIG. 2.
Figure 5 is a diagram explaining the structure and operating principle of a hydrogen reduction system for nuclear power plants according to an embodiment of the present invention.

Specific details of the embodiments are included in the detailed description and drawings.

The advantages and features of the present invention and methods for achieving them will become clear by referring to the embodiments described in detail below along with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below and may be implemented in various different forms. The present embodiments are merely provided to ensure that the disclosure of the present invention is complete and to be understood by those skilled in the art. It is provided to fully inform those who have the scope of the invention, and the present invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout the specification.

Hereinafter, the present invention will be described with reference to drawings for explaining a hydrogen reduction system for nuclear power plants according to embodiments of the present invention.

FIG. 2 is a plan view of a hydrogen reduction system for a nuclear power plant according to an embodiment of the present invention, FIG. 3 is a cross-sectional view in the direction a of FIG. 2, FIG. 4 is a cross-sectional view in the b direction of FIG. 2, and FIG. This is a diagram explaining the structure and operating principle of a hydrogen reduction system for nuclear power plants according to an embodiment of the present invention.

The hydrogen reduction system for nuclear power plants according to an embodiment of the present invention may include a passive catalytic hydrogen recombiner (100) and a thermoelectric generator (TEG) (200). In addition, it may further include a fan 150, a hydrogen ignitor 300, and a capacitor 500.

The passive catalytic hydrogen material combiner 100 has a housing 110 formed with an inlet 101 through which air flows in and an outlet 102 through which the introduced air is discharged, and the inside of the housing 110 is coated to form a chemical reaction between the hydrogen contained in the air and the It may be configured to include a catalyst 120 that induces a reaction to remove hydrogen.

The housing 110 is formed in a box shape that penetrates up and down, allowing air to flow from bottom to top through the inlet 101 formed on the lower side and the outlet 102 formed on the upper side.

The catalyst 120 coated on the inside of the housing 110 may be palladium or platinum. Hydrogen and oxygen in the air react by the catalyst 120 to generate water and remove hydrogen. In the drawing, the catalyst 120 is shown coated on the inner surface of the housing 110. However, a plurality of slits (not shown) may be provided inside the lower end of the housing 110 and the catalyst may be coated on the slit surface. there is.

Oxygen and hydrogen are generally recombined through rapid combustion at a high temperature of 593°C or higher, but when the above catalyst 120 material is present, combustion by the catalyst 120 occurs at a temperature lower than 0°C, and the catalyst 120 Adsorption occurs due to attractive forces between oxygen and hydrogen atoms or molecules on the metal surface. Using this reaction between hydrogen and oxygen on the surface of the catalyst 120, hydrogen in the air can be removed to reduce the hydrogen concentration.

The catalyst 120 reaction as described above is an exothermic reaction. Accordingly, the reaction heat generated on the metal surface of the catalyst 120 heats the surrounding air, causing a circulation effect by natural convection, allowing air to continuously circulate from the lower part of the housing 110 to the upper part.

The thermoelectric generator 200 generates electricity using heat generated by a catalytic reaction in the driven catalytic hydrogen material combiner 100. The thermoelectric generator 200 is a power conversion system utilizing a thermoelectric element 205 and is a device that generates power using the Seebeck effect, which generates a potential difference inside a closed circuit due to a temperature difference.

In the thermoelectric generator 200, a high temperature portion may be disposed on one side of the thermoelectric element 205 and a low temperature portion may be disposed on the other side of the thermoelectric element 205. The thermoelectric generator 200 can generate electricity by the temperature difference between the high-temperature section and the low-temperature section. The larger the temperature difference between the high-temperature section and the low-temperature section, the higher the electricity generation efficiency.

As shown, the thermoelectric generator 200 may be disposed on the outer surface of the housing 110 of the driven catalytic hydrogen material combiner 100. At this time, the high temperature part may be formed on the side in contact with the housing 110 of the driven catalytic hydrogen material combiner 100, and the low temperature part may be the cooling fin 210 formed on the outer surface of the thermoelectric generator 200.

Alternatively, the thermoelectric generator 200 may be formed in a separate location from the driven catalyst-type hydrogen material combiner 100.

In this case, a heat pipe 400 is disposed between the driven catalytic hydrogen combiner 100 and the thermoelectric generator 200 and transfers the heat generated by the catalytic reaction of the driven catalytic hydrogen combiner 100 to the thermoelectric generator 200. More may be included.

The heat pipe 400 is a known device that performs heat transfer by utilizing the phase change and capillary phenomenon of a working fluid within a metal pipe. In the evaporation section of the heat pipe 400, the working fluid receives heat and evaporates, and the evaporated gas releases heat as the working fluid condenses in the condensation section on the other side. The condensed working fluid moves back to the evaporation unit along the porous structure by capillary action. Therefore, heat can be passively transferred from the evaporation unit to the condensation unit without the need for a device such as a pump to force the fluid to flow. At this time, the working fluid in the evaporation part of the heat pipe 400 receives heat from the driven catalyst type hydrogen material combiner 100, and transfers heat to the thermoelectric element 205 through the working fluid in the condensation part of the heat pipe 400. It will be delivered.

In the present invention, hydrogen in the air is reduced using electricity generated by the thermoelectric generator 200 without external power supply, and hydrogen can be reliably removed from the facility even in the event of a serious accident.

As an example, the driven catalytic hydrogen material combiner 100 is provided with a fan 150 that guides air supply toward the inside of the housing 110, and the fan 150 uses electricity generated by the thermoelectric generator 200. It can work. As shown, the fan 150 may be placed on the inlet side of the housing 110.

By operating the fan 150 to artificially supply external air into the housing 110, hydrogen reduction efficiency by catalytic reaction can be increased compared to circulation by natural convection. In addition, since air is artificially circulated inside the housing 110 by the fan 150, the size of the housing 110 can be miniaturized compared to the existing passive catalytic hydrogen material combiner 100.

As another example, a hydrogen igniter 300 is provided to remove hydrogen by burning hydrogen in the air, and the hydrogen igniter 300 can operate using electricity generated by the thermoelectric generator 200. The hydrogen igniter 300 is a device that burns hydrogen little by little to change it into water, and can burn hydrogen when the hydrogen concentration is 5% or more. At this time, power is required to operate the hydrogen igniter 300, and in the present invention, the hydrogen igniter 300 can be operated using electricity generated by the thermoelectric generator 200 described above.

In this way, since hydrogen can be reduced using not only the driven catalyst type hydrogen material combiner 100 but also the hydrogen igniter 300, hydrogen reduction efficiency can be increased.

At this time, the hydrogen igniter 300 may be formed integrally with the driven catalytic hydrogen material coupler 100 on the outer surface of the housing 110 of the driven catalytic hydrogen material coupler 100, as shown.

In addition, it may further include a hydrogen concentration measurement sensor 600 that measures the concentration of hydrogen in the air.

In addition, the present invention may further include a temperature measuring sensor (not shown) that measures the temperature around the catalyst of the driven catalyst type hydrogen material combiner 100.

The control unit (not shown) is a control device consisting of a CPU and a storage device and controls the operation of the hydrogen reduction system of the nuclear power plant.

The control unit may receive the hydrogen concentration in the air measured from the hydrogen concentration measurement sensor 600 and control the operation of the hydrogen igniter 300 based on this. For example, when the hydrogen concentration in the air exceeds a preset threshold, the hydrogen igniter 300 may be operated. In general, the hydrogen removal performance of the hydrogen igniter (300) is superior compared to the passive catalytic hydrogen recombiner (100). In the present invention, when the concentration of hydrogen in the air is high, the hydrogen igniter (300) is operated to immediately remove hydrogen before hydrogen explosion. It can lower the concentration of hydrogen in the air.

Additionally, the control unit may receive the hydrogen concentration in the air measured from the hydrogen concentration measurement sensor 600 and control the operation of the fan 150 based on this. For example, if the hydrogen concentration value in the air is high, the rotation speed of the fan 150 can be increased to increase the hydrogen reduction rate, and if the hydrogen concentration in the air is low, the hydrogen reduction rate can be lowered by relatively lowering the rotation speed of the fan 150. there is.

The control unit may receive the temperature around the catalyst 120 measured from a temperature sensor and control the operation of the fan 150 based on this.

In the present invention, the temperature around the catalyst 120 can be lowered by the operation of the thermoelectric generator 200. However, despite the operation of the thermoelectric generator 200, the ambient temperature becomes too high due to the exothermic reaction of the catalyst 120, and the catalyst 120 ), a problem in which the catalyst 120 ignites may occur if the temperature becomes higher than the natural ignition temperature.

Accordingly, in the present invention, the speed of the fan 150 can be controlled so that the temperature of the surrounding gas does not become higher than the spontaneous ignition temperature of the catalyst 120. If the temperature value around the catalyst 120 measured from the temperature measurement sensor is high, the rotation speed of the fan 150 is lowered to reduce the amount of reaction by the catalyst 120, and if the temperature value measured from the temperature measurement sensor is low, the catalyst (120) is lowered. The rotation speed of the fan 150 can be increased to increase the amount of reaction by 120).

As such, the present invention also has the advantage of establishing an optimal hydrogen concentration control method by constructing an intelligent system by operating a fan or hydrogen igniter according to the hydrogen concentration measured by the sensor or the temperature around the catalyst.

In addition, it may further include a capacitor 500 that stores electricity generated by the thermoelectric generator 200. The electricity generated by the thermoelectric generator 200 can be used immediately, but the fan 150, hydrogen igniter 300, control unit, hydrogen concentration measurement sensor 600, etc. can be operated using electricity stored in the capacitor.

The scope of the present invention is not limited to the above-described embodiments, but may be implemented in various forms of embodiments within the scope of the appended claims. It is considered to be within the scope of the claims of the present invention to the extent that anyone skilled in the art can make modifications without departing from the gist of the invention as claimed in the claims.

100: Passive catalyst type hydrogen material combiner
101: inlet
102: outlet
110: housing
120: catalyst
150: fan
200: Thermoelectric generator
205: thermoelectric element
210: Cooling fin
300: Hydrogen igniter
400: heat pipe
500: Capacitor
600: Hydrogen concentration measurement sensor

Claims (10)

A passive catalytic hydrogen recombiner comprising a housing formed with an inlet through which air flows in and an outlet through which air is discharged, and a catalyst coated on the inside of the housing to induce a chemical reaction with hydrogen contained in the introduced air to remove hydrogen; and
A thermoelectric generator that generates electricity using heat generated by the catalytic reaction in the passive catalytic hydrogen material combiner,
A hydrogen reduction system for nuclear power plants, characterized in that hydrogen is reduced without supplying power from the outside. According to claim 1,
Further comprising a fan that induces air supply within the housing,
The fan is a hydrogen reduction system for nuclear power plants that operates using electricity generated from the thermoelectric generator. According to claim 1,
A hydrogen reduction system for a nuclear power plant, further comprising a heat pipe disposed between the passive catalytic hydrogen combiner and the thermoelectric generator to transfer heat generated by a catalytic reaction of the passive catalytic hydrogen combiner to the thermoelectric generator. According to claim 1,
It further includes a hydrogen igniter that removes hydrogen from the air by burning hydrogen,
The hydrogen igniter is a hydrogen reduction system for nuclear power plants that operates using electricity generated from the thermoelectric generator. According to clause 4,
The hydrogen igniter is a hydrogen reduction system for nuclear power plants formed on the outer surface of the housing. According to clause 4,
Hydrogen concentration sensor that measures the concentration of hydrogen in the air; and
It further includes a control unit that receives the hydrogen concentration in the air measured from the hydrogen concentration measurement sensor and controls the operation of the hydrogen igniter,
The control unit operates the hydrogen igniter when the hydrogen concentration in the air received from the hydrogen concentration measurement sensor exceeds a threshold. According to clause 2,
It further includes a hydrogen igniter that removes hydrogen from the air by burning hydrogen,
The hydrogen igniter is a hydrogen reduction system for nuclear power plants that operates using electricity generated from the thermoelectric generator. According to clause 7,
Hydrogen concentration sensor that measures the concentration of hydrogen in the air; and
A hydrogen reduction system for a nuclear power plant further comprising a control unit that receives the hydrogen concentration in the air measured from the hydrogen concentration measurement sensor and controls the operation of the fan. According to clause 2,
A temperature sensor that measures the temperature around the catalyst; and
It further includes a control unit that receives the temperature measured from the temperature measurement sensor and controls the operation of the fan,
The control unit operates the fan to maintain the temperature of the air input from the temperature measurement sensor below a set threshold. According to claim 1,
A hydrogen reduction system for nuclear power plants, further comprising a capacitor for storing electricity generated from the thermoelectric generator.

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