Hydrogen countermeasure purge system inside reactor building

Abstract

To enable direct hydrogen processing to a small room in a reactor building, have a self-standing property usable even when a power source is lost, and enable suppressing an increase in temperature in the small room.SOLUTION: A hydrogen countermeasure purge system in a reactor building comprises: a gas supply unit that supplies purge-purpose gas for reducing the hydrogen concentration in a reactor building; a temperature measurement unit that measures a temperature increase in the small room; a hydrogen concentration estimation unit that estimates the hydrogen concentration in the small room on the basis of the temperature increase in the small room measured by the temperature measurement unit; and an adjustment unit that adjusts an amount of supply of the purge-purpose gas by the gas supply unit in accordance with the hydrogen concentration estimated by the hydrogen concentration estimation unit. The purge system is configured to supply the purge-purpose gas adjusted by the adjustment unit from the gas supply unit to the small room to dilute the hydrogen concentration in the small room in accordance with the hydrogen concentration, and thereby make the hydrogen concentration in the small room less than a combustible limit.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a purge system for preventing hydrogen contamination in a reactor building, and more particularly to a purge system for preventing hydrogen contamination in a reactor building that is suitable for installation in a small room in a reactor building that has a smaller volume than a reactor pressure vessel. [Background technology]

[0002] In general, in a nuclear power plant, if an accident occurs in which the reactor core located inside the reactor pressure vessel melts (hereinafter referred to as a severe accident), hydrogen gas may be generated inside the reactor containment vessel due to a metal-water reaction, and hydrogen and oxygen gas may be generated due to radioactive decomposition of water. The concentration of flammable gases such as hydrogen generated inside the reactor containment vessel is designed to be controlled below the flammable limit by a flammable gas concentration control system.

[0003] However, in the event of a serious accident, flammable gases such as hydrogen generated inside the reactor containment vessel may leak into a small room inside the reactor building. If a leakage of flammable gases such as hydrogen were to occur in an amount far greater than anticipated, hydrogen would accumulate in the small room and there is a non-zero possibility of combustion occurring.

[0004] As a measure against hydrogen inside a reactor building, for example, Patent Document 1 proposes exhausting the gas by an emergency gas treatment system.

[0005] According to Patent Document 1, by activating the emergency gas treatment system, hydrogen that has leaked from the reactor containment vessel into the reactor building can be released into the outside air from the main steam stack, preventing hydrogen from burning inside the reactor building.

[0006] Furthermore, as a method for treating hydrogen inside a reactor building, for example, there is a technique described in Patent Document 2.

[0007] According to Patent Document 2, by installing a catalytic recombination device inside the reactor building, the combustible gases hydrogen and oxygen generated inside the reactor containment vessel are recombined into water by the catalytic layer contained in the catalyst. As a result, the combustible gas concentration is suppressed below the flammable limit, making it possible to passively prevent the combustion of combustible gas even in the event of a total power loss. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] JP 2015-232492 A [Patent Document 2] JP 2011-174773 A Summary of the Invention [Problem to be solved by the invention]

[0009] However, in the above-mentioned Patent Document 1, when treating hydrogen that has leaked into a small room inside a reactor building, it is necessary to indirectly vent the hydrogen inside the small room via a duct from a location away from the target small room, which poses the problem that direct hydrogen treatment is not possible.

[0010] In addition, in the above-mentioned Patent Document 2, if a catalytic recombination device is installed in a small room inside the reactor building, the volume of the small room is small, so the temperature inside the small room is likely to rise due to the reaction heat of hydrogen combustion or recombination, which may have an adverse effect on workers entering the room and on equipment.

[0011] The present invention has been made in consideration of the above-mentioned points, and an object of the present invention is to provide a purge system for hydrogen countermeasures within a reactor building that can directly treat hydrogen in a small room within the reactor building, is autonomous so that it can be used even in the event of a power loss, and can suppress a temperature rise within the small room. [Means for solving the problem]

[0012] In order to achieve the above object, the present invention provides a purge system for hydrogen countermeasures in a reactor building, which comprises a reactor pressure vessel, a reactor containment vessel installed on the outer periphery of the reactor pressure vessel at a predetermined distance, and a small room which communicates with the inside of the reactor containment vessel via a penetration and has a smaller volume than the reactor pressure vessel, and which suppresses the concentration of hydrogen leaking from the reactor containment vessel to the small room, The hydrogen countermeasure purge system includes a gas supply unit that supplies a purge gas for reducing a hydrogen concentration inside the small room, a temperature measurement unit that measures a temperature rise inside the small room, a hydrogen concentration estimation unit that estimates a hydrogen concentration inside the small room based on the temperature rise inside the small room measured by the temperature measurement unit, and an adjustment unit that adjusts the amount of the purge gas supplied by the gas supply unit in accordance with the hydrogen concentration estimated by the hydrogen concentration estimation unit, and supplies the purge gas from the gas supply unit adjusted by the adjustment unit into the small room to dilute the hydrogen concentration inside the small room in accordance with the hydrogen concentration, thereby making the hydrogen concentration inside the small room less than the flammable limit. The hydrogen countermeasure purge system comprises an air conditioner which is the gas supply unit installed inside the small room, a purge gas pipe which is connected to the air conditioner at one end and which ejects the purge gas from the air conditioner from the other end into the small room, a temperature measurement and hydrogen concentration estimator having the functions of the temperature measurement unit and the hydrogen concentration estimation unit, and an adjustment valve which is installed midway along the purge gas pipe and has the function of the adjustment unit, and which ejects the purge gas from the air conditioner which has been adjusted by the adjustment valve into the small room to dilute the hydrogen concentration in the small room in accordance with the hydrogen concentration, thereby making the hydrogen concentration in the small room less than the flammability limit. It is characterized by: Effect of the Invention

[0013] According to the present invention, hydrogen treatment can be performed directly in a small room inside a reactor building, the room is self-sustaining and can be used even in the event of a power loss, and temperature rise inside the small room can be suppressed. [Brief description of the drawings]

[0014] [Figure 1] 1 is a cross-sectional view of the inside of a reactor building according to a first embodiment of a purge system for dealing with hydrogen inside a reactor building of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view of the inside of a small room in a reactor building according to a first embodiment of the purge system for dealing with hydrogen in a reactor building of the present invention. [Diagram 3] FIG. 11 is a cross-sectional view of the inside of a small room in a reactor building according to a second embodiment of the purge system for dealing with hydrogen in a reactor building of the present invention. [Figure 4]FIG. 11 is a cross-sectional view of the inside of a small room in a reactor building according to a third embodiment of the purge system for dealing with hydrogen in a reactor building of the present invention. [Diagram 5] FIG. 11 is a cross-sectional view of the inside of a small room in a reactor building according to a fourth embodiment of the purge system for dealing with hydrogen in a reactor building of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] The hydrogen countermeasure purge system for use in a reactor building according to the present invention will be described below based on the illustrated embodiments. In each embodiment, the same components are designated by the same reference numerals, and duplicated explanations will be omitted. EXAMPLES

[0016] A first embodiment of the hydrogen countermeasure purge system in a reactor building of the present invention will be described with reference to Figures 1 and 2. Figure 1 is a cross-sectional view of the inside of a reactor building 1 according to the first embodiment of the hydrogen countermeasure purge system in a reactor building of the present invention, and Figure 2 is a cross-sectional view of the inside of a small room 5 in the reactor building 1 according to the first embodiment of the hydrogen countermeasure purge system in a reactor building of the present invention.

[0017] As shown in FIG. 1, a reactor building 1 contains a reactor pressure vessel 2, a reactor containment vessel 3 installed at a distance from the outer periphery of the reactor pressure vessel 2, and a small room 5 which is connected to the inside of the reactor containment vessel 3 via a penetration 4 and has a smaller volume than the reactor pressure vessel 2. The hydrogen countermeasure purge system in the reactor building in this embodiment is intended to suppress the concentration of hydrogen leaking from the reactor containment vessel 3 to the small room 5.

[0018] As shown in FIG. 2, the hydrogen countermeasure purge system in the reactor building in this embodiment is roughly composed of a gas cylinder 7 which is installed inside the small room 5 and serves as a gas supply unit that supplies purge gas to reduce the hydrogen concentration inside the small room 5, a purge gas pipe 10 which is connected at one end to the gas cylinder 7 and sprays the purge gas in the gas cylinder 7 from the other end into the small room 5, a temperature measurement and hydrogen concentration estimator 9 which has the function of a temperature measurement unit that measures the temperature rise inside the small room 5 and the function of a hydrogen concentration estimation unit that estimates the hydrogen concentration inside the small room 5 based on the temperature rise inside the small room 5 measured by the temperature measurement unit, and an adjustment valve 8 which is installed midway through the purge gas pipe 10 and has the function of an adjustment unit that adjusts the amount of purge gas supplied by the gas cylinder 7 in accordance with the hydrogen concentration estimated by the temperature measurement and hydrogen concentration estimator 9.

[0019] The hydrogen countermeasure purge system in the reactor building of this embodiment described above sprays purge gas from the gas cylinder 7, which is regulated by the regulating valve 8, into the small room 5, diluting the hydrogen concentration in the small room 5 in accordance with the hydrogen concentration, thereby suppressing the hydrogen concentration in the small room 5 to below the flammability limit.

[0020] The hydrogen countermeasure purge system for use in a reactor building according to this embodiment will now be described in detail.

[0021] For example, in the event of a serious accident such as melting of the reactor core located in the reactor pressure vessel 2, if hydrogen generated in the reactor containment vessel 3 leaks from the penetration 4 into a small room 5 in the reactor building 1, the temperature measurement and hydrogen concentration estimator 9 will detect the temperature rise and hydrogen concentration due to the hydrogen leakage in the small room 5.

[0022] The temperature measurement and hydrogen concentration estimator 9 may, for example, use a number of catalytic combustion sensors, some with a catalyst and some without a catalyst (note that the catalyst reacts with hydrogen, and the presence of hydrogen in the small chamber 5 can be detected by the reaction of the catalyst with hydrogen).

[0023] In this catalytic combustion sensor, the temperature of the sensor equipped with a catalyst rises as it reacts with hydrogen, and as the temperature of the sensor rises, the resistance value increases, causing an unbalanced current to flow between the sensor equipped with a catalyst and the sensor equipped with no catalyst. Since the magnitude of this unbalanced current is proportional to the hydrogen concentration below the flammable limit concentration, it is possible to estimate the hydrogen concentration by knowing the magnitude of the unbalanced current, and it is hardly affected by the environmental temperature and humidity.

[0024] The opening of the regulating valve 8 is adjusted according to the hydrogen concentration estimated by this temperature measurement and hydrogen concentration estimator 9, and the amount of purge gas sprayed from the gas cylinder 7 via the purge gas piping 10 is passively adjusted.

[0025] The purge gas in the gas cylinder 7 may be, for example, an inert gas such as nitrogen, argon, or carbon dioxide. In addition, when considering the entry of workers into the small room 5, air may be used.

[0026] Furthermore, the amount of purge gas ejected from the gas cylinder 7 via the purge gas piping 10 is sufficient to suppress the hydrogen concentration below the flammability limit (to reduce the hydrogen concentration below the flammability limit), and the amount of purge gas ejected is adjusted according to the hydrogen concentration (for example, if the hydrogen concentration is high, the amount of purge gas ejected is increased, and if the hydrogen concentration is low, the amount of purge gas ejected is decreased), so that the hydrogen concentration in the small room 5 can be suppressed below the flammability limit even if hydrogen leakage continues for a long period of time from inside the reactor containment vessel 3.

[0027] Although not shown, a detector installed in the small room 5 detects that the hydrogen concentration in the small room 5 is below the flammable limit.

[0028] The hydrogen purged by the purge gas ejected from the gas cylinder 7 via the purge gas piping 10 is exhausted to the outside of the small chamber 5 through an opening 11 in the small chamber 5 or a piping (not shown) and disposed of.

[0029] Incidentally, even in places where hydrogen is likely to accumulate locally, such as recesses in the small chamber 5, the hydrogen concentration can be uniformly diluted by the effect of convection caused by the purge gas.

[0030] As a result, even in the event of a power loss, the hydrogen concentration in small chamber 5 can be passively suppressed to below the flammable limit, preventing combustion.

[0031] Therefore, according to this embodiment, hydrogen treatment can be performed directly in the small room 5 inside the reactor building 1, the small room 5 is self-sustaining and can be used even when power is lost, and the temperature rise inside the small room 5 can be suppressed.

[0032] The small room 5 may be a room that has the potential for hydrogen leakage from the reactor containment vessel, such as the hatch room for carrying in equipment, the airlock room for personnel, the suppression chamber entrance room, etc., and rooms adjacent to these. The volume of these rooms is about 100 m. 3 This is the same in each of the embodiments described below. EXAMPLES

[0033] FIG. 3 shows the inside of a small room 5 in a reactor building 1 according to a second embodiment of the purge system for dealing with hydrogen in a reactor building of the present invention.

[0034] Example 2 shown in Fig. 3 is a modified example of Example 1, and in this example shown in Fig. 2, the gas cylinder 7 is installed outside the small room 5, and a purge gas pipe 10 for spraying the purge gas into the small room 5 is installed so as to connect the outside to the inside of the small room 5. The rest of the configuration is the same as that of Example 1 shown in Fig. 2.

[0035] As a result, the purge gas is ejected from the gas cylinder 7 through the purge gas pipe 10 into the small room 5. The amount of ejected gas is adjusted according to the hydrogen concentration estimated by the temperature measurement and the hydrogen concentration estimator 9, so that the hydrogen concentration in the small room 5 can be suppressed below the flammable limit.

[0036] In addition, by installing a gas cylinder 7 outside the small room 5, when the gas in the gas cylinder 7 runs low, it is possible to supply purging gas to the small room 5 for a long period of time by switching to another gas cylinder.

[0037] The hydrogen concentration in the small room 5 can also be suppressed below the flammable limit by connecting the purge gas piping 10 to an inert gas system that can supply inert gas instead of the gas cylinder 7. This is possible because the inert gas system is located outside the small room 5, and is not possible with the configuration of Example 1 in FIG.

[0038] Even with such a configuration of this embodiment, the effects are the same as those of the first embodiment. EXAMPLES

[0039] FIG. 4 shows the inside of a small room 5 in a reactor building 1 according to a third embodiment of the purge system for dealing with hydrogen in a reactor building of the present invention.

[0040] Example 3 shown in Fig. 4 is a modified example of Example 1, and in this example shown in Fig. 4, a catalytic recombination device 13 for suppressing reaction heat during hydrogen treatment is installed in the center of the lower part inside the small chamber 5. The rest of the configuration is the same as that of Example 1 shown in Fig. 2.

[0041] By installing the above-mentioned catalytic recombination device 13 at the bottom inside the small chamber 5, hydrogen and oxygen are recombined into water by the catalytic layer contained in the catalyst. In addition, the opening of the regulating valve 8 is adjusted according to the hydrogen concentration estimated by the temperature measurement and hydrogen concentration estimator 9, and purge gas is sprayed from the gas cylinder 7 through the purge gas piping 10 into the small chamber 5.

[0042] This makes it possible to dilute the hydrogen concentration in the small chamber 5 and suppress the reaction heat generated during hydrogen processing by the catalytic recombination device 13, thereby enabling hydrogen to be processed without adversely affecting the equipment 6 in the small chamber 5.

[0043] Furthermore, by combining purging with gas from the gas cylinder 7 and hydrogen processing using the catalytic recombination device 13, more efficient hydrogen processing is possible, and the hydrogen concentration in the small chamber 5 can be kept below the flammable limit, preventing combustion.

[0044] Even with such a configuration of this embodiment, the effects are the same as those of the first embodiment. EXAMPLES

[0045] FIG. 5 shows the inside of a small room 5 in a reactor building 1 according to a fourth embodiment of the purge system for dealing with hydrogen in a reactor building of the present invention.

[0046] Example 4 shown in FIG. 5 is a modified example of Example 1. In this example shown in FIG. 5, an air conditioner 12 is installed in the small room 5 instead of the gas cylinder 7, assuming that the emergency power supply is restored.

[0047] The hydrogen countermeasure purge system inside the reactor building in this embodiment is similar to the configuration of embodiment 1 in Figure 2 in that it comprises a purge gas piping 10 connected at one end to an air conditioner 12 and spraying purge gas from the air conditioner 12 into the small room 5 from the other end, a temperature measurement and hydrogen concentration estimator 9 having the functions of the temperature measurement section and the hydrogen concentration estimation section described above, and an adjustment valve 8 installed midway along the purge gas piping 10 and having the functions of the adjustment section described above.

[0048] The air conditioner 12 may be installed anywhere in the small room 5, but is preferably installed in a location that facilitates convection.

[0049] By configuring this embodiment as described above, the amount of purge gas supplied from the air conditioner 12 can be adjusted by the regulating valve 8 in accordance with the hydrogen concentration estimated by temperature measurement and the hydrogen concentration estimator 9, thereby suppressing the hydrogen concentration in the small room 5 below the flammable limit.

[0050] Furthermore, in this embodiment, the gas cylinder 7 as in the above-mentioned embodiments 1-3 is not necessary, and when a power source is available, it is advisable to use the air conditioner 12 of this embodiment.

[0051] Even with such a configuration of this embodiment, the effects are the same as those of the first embodiment.

[0052] The present invention is not limited to the above-described embodiments, and includes various modified examples. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to those including all of the configurations described. In addition, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. In addition, it is possible to add, delete, or replace a part of the configuration of each embodiment with another configuration. [Explanation of symbols]

[0053] 1...reactor building, 2...reactor pressure vessel, 3...reactor containment vessel, 4...penetration, 5...small room, 6...equipment, 7...gas cylinder, 8...regulating valve, 9...temperature measurement and hydrogen concentration estimator, 10...purge gas piping, 11...opening, 12...air conditioner, 13...catalytic recombination device.

Claims

1. A hydrogen countermeasure purge system for a reactor building that contains a reactor pressure vessel, a reactor containment vessel installed on the outer periphery of the reactor pressure vessel at a predetermined interval, and a small room that communicates with the inside of the reactor containment vessel through a penetration and has a smaller volume than the reactor pressure vessel, the purge system being configured to suppress a hydrogen concentration leaked from the reactor containment vessel to the small room, The hydrogen countermeasure purge system includes a gas supply unit that supplies a purge gas for reducing a hydrogen concentration in the small room, a temperature measurement unit that measures a temperature rise in the small room, a hydrogen concentration estimation unit that estimates a hydrogen concentration in the small room based on the temperature rise in the small room measured by the temperature measurement unit, and an adjustment unit that adjusts the amount of the purge gas supplied by the gas supply unit in accordance with the hydrogen concentration estimated by the hydrogen concentration estimation unit, The purge gas from the gas supply unit adjusted by the adjustment unit is supplied into the small chamber to dilute the hydrogen concentration in the small chamber in accordance with the hydrogen concentration, and the hydrogen concentration in the small chamber is made to be less than the flammable limit, The hydrogen countermeasure purge system comprises an air conditioner which is the gas supply unit installed inside the small room, a purge gas pipe which is connected to the air conditioner at one end and which sprays the purge gas from the air conditioner from the other end into the small room, a temperature measurement and hydrogen concentration estimator having the functions of the temperature measurement unit and the hydrogen concentration estimation unit, and an adjustment valve which is installed midway along the purge gas pipe and has the function of the adjustment unit, A hydrogen countermeasure purge system in a reactor building, characterized in that the purge gas from the air conditioner regulated by the regulating valve is sprayed into the small room to dilute the hydrogen concentration in the small room in accordance with the hydrogen concentration, thereby making the hydrogen concentration in the small room below the flammability limit.

2. A purge system for hydrogen countermeasures in a reactor building according to claim 1, the temperature measurement and hydrogen concentration estimation device is a catalytic combustion sensor having a plurality of sensors, some of which include a catalyst and some of which do not include a catalyst; The catalytic combustion sensor is a hydrogen countermeasure purge system for use in a reactor building, characterized in that the temperature of the catalytic combustion sensor rises as the sensor equipped with a catalyst reacts with hydrogen, and as the temperature of the sensor rises, its resistance value increases, causing an unbalanced current to flow between the sensor equipped with a catalyst and the sensor equipped with no catalyst, and the hydrogen concentration can be estimated by determining the magnitude of this unbalanced current.

3. A purge system for hydrogen countermeasures in a reactor building according to claim 2, A purge system for dealing with hydrogen in a reactor building, characterized in that the opening of the regulating valve is adjusted in accordance with the temperature measurement and the hydrogen concentration estimated by the hydrogen concentration estimator, and the amount of the purge gas sprayed from the air conditioner through the purge gas piping is adjusted.

4. A purge system for hydrogen countermeasures in a reactor building according to claim 3, A purge system for dealing with hydrogen in a reactor building, characterized in that if the hydrogen concentration is high, the amount of purge gas ejected is increased, and if the hydrogen concentration is low, the amount of purge gas ejected is decreased.

5. A purge system for hydrogen countermeasures in a reactor building according to claim 4, 1. A purge system for hydrogen countermeasures in a reactor building, wherein the small room has an opening or a pipe for discharging purged hydrogen to the outside of the small room.

6. A purge system for hydrogen countermeasures in a reactor building according to any one of claims 1 to 5, A purge system for hydrogen countermeasures in a reactor building, wherein the small room in the reactor building is any of rooms that have the potential for hydrogen leakage from the reactor containment vessel, such as an equipment entrance hatch room, an airlock room for personnel, and a suppression chamber entrance room, or rooms adjacent to these.

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