Post-treatment system for hydrogen risk accident of small-space containment and control method of post-treatment system

Abstract

The invention relates to the technical field of nuclear power facility safety treatment, and discloses a hydrogen risk accident post-treatment system for a small-space containment and a control method thereof.The system comprises an inert gas supply device, an oxygen supply device, a gas mixing device, a hydrogen reaction device, a tail gas treatment device and a processor; the inert gas supply device, the oxygen supply device and the containment are respectively connected to the gas mixing device, a first valve is arranged between the containment and the gas mixing device, the hydrogen concentration detection device and the first valve are both connected to the processor, and the processor can detect the hydrogen concentration according to the hydrogen concentration detected by the hydrogen concentration detection device. The opening degree of the first valve is controlled, so that the hydrogen concentration in the gas mixing device is lower than a set value; the gas mixing device is connected with a hydrogen reaction device which is connected with a tail gas treatment device. According to the invention, high-concentration hydrogen in the small-space containment in the later stage of a serious accident can be safely output and treated, and potential safety hazards are eliminated.

Description

Technical Field

[0001] The present invention relates to the technical field of safe processing of nuclear power facilities, and in particular to a post-processing system for a small-space containment hydrogen risk accident and a control method thereof. Background Art

[0002] During a serious accident in a small or medium-sized nuclear reactor, metal materials such as zirconium alloy and stainless steel within the reactor core undergo oxidation reactions. This chemical process produces large amounts of hydrogen. After being released into the containment vessel through a breach in the primary circuit boundary, a safety valve, or a pressure relief valve, the hydrogen migrates and diffuses within the containment vessel, mixing with the water vapor released from the primary circuit and the air within the containment vessel, forming a cloud of flammable mixed gas. When the hydrogen concentration within the containment vessel reaches a certain proportion, under certain conditions (such as temperature, pressure, and oxygen concentration), hydrogen combustion or explosion may occur. The small containment vessels used in small and medium-sized light-water reactors are relatively small. An explosion of the flammable mixed gas could damage safety equipment and systems, undermine the integrity of the containment vessel, and result in a large release of radioactive material.

[0003] Regarding the hydrogen risk control under severe accidents of small and medium-sized nuclear reactors, in the early stage of a severe accident, a passive hydrogen recombiner or igniter is used to consume all the oxygen in the containment, and the hydrogen oxidation reaction gradually stops. As the accident further develops, the hydrogen released from the primary circuit will further accumulate in the containment. In the later stage of a severe accident, the high concentration of hydrogen in the small space containment needs to be further treated to completely eliminate the risk of hydrogen combustion and explosion in the small space containment.

[0004] Small and medium-sized nuclear reactors generally use small-space containment with low manufacturing costs. The devices in the small-space containment are compactly arranged and the free space is small, which makes it difficult to layout conventional hydrogen removal equipment. At the same time, in the middle and late stages of a serious accident, when the oxygen in the small-space containment is exhausted, a high concentration of hydrogen accumulates in the small-space containment. In the absence of oxygen, it is difficult for the hydrogen removal equipment to carry out the hydrogen removal reaction. Summary of the Invention

[0005] The present invention addresses the problem that in the middle and late stages of a serious accident, when the oxygen in a small space containment is exhausted, a high concentration of hydrogen accumulates in the small space containment, and at the same time, factors such as the small space of the containment make it difficult for conventional hydrogen removal equipment to implement the hydrogen removal reaction. The present invention provides a post-processing system and control method for hydrogen risk accidents in a small space containment, which can safely output and process the high concentration of hydrogen in the small space containment, so as to eliminate the possibility that the high concentration of hydrogen accumulated in the small space containment may leak out of the containment, thereby causing the hydrogen risk to further expand to more places.

[0006] The present invention is achieved through the following technical solutions:

[0007] A post-processing system for a hydrogen risk accident in a small space containment, comprising an inert gas supply device, an oxygen supply device, a gas mixing device, a hydrogen reaction device, an exhaust gas treatment device and a processor, wherein the inert gas supply device, the oxygen supply device and the containment are respectively connected to the gas mixing device, a first valve is provided between the containment and the gas mixing device, a hydrogen concentration detection device is provided in the gas mixing device, the hydrogen concentration detection device and the first valve are both connected to the processor, and the processor can control the opening of the first valve according to the hydrogen concentration detected by the hydrogen concentration detection device so that the hydrogen concentration in the gas mixing device is lower than the set value; the gas mixing device is connected to the hydrogen reaction device, and the hydrogen reaction device is connected to the exhaust gas treatment device.

[0008] Optionally, a gas heater is further connected between the inert gas supply device and the gas mixing device.

[0009] Optionally, the oxygen supply device includes a blower connected to an air delivery pipe, and the blower is connected to the gas mixing device.

[0010] Optionally, the hydrogen reaction device includes a hydrogen reaction chamber, in which a hydrogen recombiner is provided.

[0011] Optionally, the exhaust gas treatment device includes an exhaust gas cooling box, in which cooling water and a cooler for cooling the cooling water are provided, and the exhaust gas in the exhaust gas cooling box is passed into the gas mixing device.

[0012] The control method for a small space containment hydrogen risk accident post-processing system comprises the following steps:

[0013] Step 1: Turn on the inert gas supply device and introduce the inert gas into the gas mixing device through the gas heater and the second valve in sequence;

[0014] Step 2: Turn on the fan, open the third valve, and extract air from the atmospheric environment through the air delivery pipe and deliver it to the gas mixing device;

[0015] Step 3: After the gas transported in steps 1 and 2 is stabilized, the first valve is opened to connect the pipeline between the containment vessel and the gas mixing device;

[0016] Step 4: monitoring the hydrogen concentration of the gas mixing device measured by the hydrogen concentration detection device, adjusting the opening of the first valve according to the read hydrogen concentration, and controlling the hydrogen concentration of the gas mixing device to be below 3%;

[0017] Step 5: After being mixed in the gas mixing device, the mixed gas is introduced into the hydrogen reaction chamber. The hydrogen recombiner recombines hydrogen and oxygen at room temperature to produce water or water vapor. The water vapor condenses on the wall of the hydrogen reaction chamber. The condensed water flows to the bottom of the hydrogen reaction chamber and then flows to the gas mixing device located at the bottom of the hydrogen reaction chamber.

[0018] Step 6: The combined exhaust gas flows from the hydrogen reaction chamber to the cooling water in the exhaust gas cooling box. Water vapor condenses in the cooling water, and the non-condensable gas in the exhaust gas flows to the gas mixing device. The cooler is used to cool the cooling water in the exhaust gas cooling box to maintain the cooling water temperature below 50°C.

[0019] Step 7: After the tail gas flows back to the gas mixing device, it is mixed with the inert gas from the inert gas supply device, the hydrogen from the containment, and the air from the air delivery pipe, and then continues to enter the hydrogen reaction chamber;

[0020] Step 8: Open the drain valve regularly to discharge the wastewater from the gas mixing device into the waste liquid treatment plant;

[0021] Step 9: Repeat steps 5 to 8 until the hydrogen concentration in the containment vessel is less than 0.5%.

[0022] The present invention also provides another technical solution:

[0023] A post-processing system for a hydrogen risk accident in a small space containment, comprising an inert gas supply device, an oxygen supply device, a gas mixing device, a hydrogen reaction device, an exhaust gas treatment device, and a processor. The inert gas supply device, the oxygen supply device, and the containment are respectively connected to the gas mixing device, the gas mixing device is connected to the hydrogen reaction device, the hydrogen reaction device is connected to the exhaust gas treatment device, and the exhaust gas treatment device is further connected to the gas mixing device.

[0024] Among them, the gas mixing device includes a gas mixer, a gas temporary chamber and a gas storage chamber in sequence. The gas mixer is respectively connected to the inert gas supply device, the oxygen supply device and the exhaust gas treatment device, and is used to mix the inert gas, oxygen and exhaust gas; a piston plate is provided in the gas temporary chamber, and a first one-way valve is provided on the piston plate. The first one-way valve is placed near the outer periphery of the piston plate. The piston plate is connected to a linear drive mechanism, which can drive the piston plate to fit with one end of the gas temporary chamber close to the gas mixer, thereby closing the gas mixer. The gas temporary chamber is provided with a hydrogen concentration detection device, and a gas compensation device is also provided between the gas temporary chamber and the gas storage chamber. The gas compensation device is respectively connected to the inert gas supply device and the containment shell.

[0025] Optionally, the gas compensation device includes a connecting pipe, the connecting pipe is provided with an air inlet hole connecting the inert gas supply device and the containment shell in a radial direction, the connecting pipe is further provided with a rotating body, one end of the rotating body is provided with an embedded portion, the embedded portion is provided with a docking hole, the embedded portion can be inserted into the air inlet hole so that the docking hole and the air inlet hole are docked, the rotating body is connected to a rotary drive mechanism, the rotary drive mechanism can drive the rotating body to rotate so that the docking hole of the rotating body can switch between the air inlet hole of the inert gas supply device, the air inlet hole of the containment shell, and a non-docking hole position;

[0026] A valve plate is also provided in the middle of the connecting pipe, on which a second one-way valve is provided. The air inlet of the inert gas supply device and the air inlet of the containment are both located on the side of the second one-way valve close to the gas temporary storage chamber.

[0027] Optionally, the first one-way valve and the second one-way valve both adopt a structure formed by a plurality of conical plates, and the back of the conical plates is connected to an elastic supporting component.

[0028] Optionally, the gas mixer includes a mixer body, which adopts a tubular structure with an intermediate cavity, and the intermediate cavity is connected to the inert gas supply device. A number of annular cavities arranged at intervals are provided on the tube wall of the mixer body, and the annular cavities are connected to the oxygen supply device, the exhaust gas treatment device and the containment shell at intervals. The annular cavity is also provided with a number of inclined holes to connect the intermediate cavity.

[0029] The technical solution of the present invention has at least the following beneficial effects:

[0030] The present invention provides a post-processing system for a hydrogen risk accident in a small space containment and a control method thereof. By providing an inert gas supply device, an oxygen supply device, and a gas mixing device outside the containment, the hydrogen in the containment is mixed with a high-concentration inert gas and air in the gas mixing device. A hydrogen reaction device is then provided to react the mixed gas in the hydrogen reaction device, thereby eliminating the hydrogen. Continuous operation can eliminate the high-concentration hydrogen accumulated in the small space containment, thereby reducing the potential risk of high-concentration hydrogen accumulated in the small space containment. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a principle block diagram of a post-processing system for a small space containment hydrogen risk accident according to Example 1 of the present invention;

[0032] Figure 2 A half-sectional view of a gas mixing device according to embodiment 2 of the present invention;

[0033] Figure 3 for Figure 2 Magnified view of part A.

[0034] Reference numerals:

[0035] 1- inert gas supply device, 2- containment vessel, 3- first valve, 4- blower, 5- air delivery pipe, 6- gas heater, 7- second valve, 8- third valve, 9- hydrogen concentration detection device, 10- hydrogen reaction chamber, 11- hydrogen recombiner, 12- gas mixing device, 13- tail gas cooling box, 14- cooler, 15- drain valve;

[0036] 121-gas mixer, 1211-annular chamber, 122-gas temporary storage chamber, 1221-linear drive mechanism, 1222-first one-way valve, 1223-piston plate, 123-gas storage chamber, 124-gas compensation device, 1241-rotating body, 1242-rotating drive mechanism, 1243-air inlet, 1244-second one-way valve. DETAILED DESCRIPTION

[0037] Example 1

[0038] Reference Figure 1 The present invention provides a post-processing system for a hydrogen risk accident in a small space containment vessel 2, comprising an inert gas supply device 1, an oxygen supply device, a gas mixing device 12, a hydrogen reaction device, an exhaust gas treatment device and a processor. The inert gas supply device 1, the oxygen supply device and the containment vessel 2 are respectively connected to the gas mixing device 12. The containment vessel 2 and the gas mixing device 12 are provided with a first valve 3. By opening the first valve 3, the gas in the containment vessel 2 can be passed into the gas mixing device 12.

[0039] In addition, a gas heater 6 and a second valve 7 are connected between the inert gas supply device 1 and the gas mixing device 12. The inert gas supply device 1 can use bottled nitrogen. By opening the second valve 7, the bottled nitrogen can be heated by the gas heater 6 and then passed into the gas mixing device 12.

[0040] The oxygen supply device includes a blower 4 connected to an air delivery pipe 5. The blower 4 is connected to a gas mixing device 12 through a third valve 8. When the blower 4 and the third valve 8 are turned on, air in the atmospheric environment can be introduced into the gas mixing device 12.

[0041] The gas mixing device 12 is provided with a hydrogen concentration detection device 9. Both the hydrogen concentration detection device 9 and the first valve 3 are connected to a processor, which can be a conventional PLC processor or a processor with similar control functions. The processor controls the opening of the first valve 3 based on the hydrogen concentration detected by the hydrogen concentration detection device 9, so that the hydrogen concentration in the gas mixing device 12 is below a set value, which in this embodiment is below 3%.

[0042] The gas mixing device 12 is connected to the hydrogen reaction device, which includes a hydrogen reaction chamber 10, within which is disposed a hydrogen recombiner 11. This recombiner 11 utilizes conventional technology in the art. The gases mixed by the gas mixing device 12 are passed into the hydrogen reaction chamber 10, where the hydrogen recombiner 11, under the action of a catalyst, causes hydrogen and oxygen to undergo a hydrogen-oxygen recombination reaction. Gases within the gas mixing device 12 enter the bottom of the hydrogen reaction chamber 10 and, after the reaction, are discharged through a pipe at the top. The chimney-like shape of the hydrogen reaction chamber 10 facilitates the flow of heated gas from the bottom of the gas mixing chamber to the outlet, creating a chimney effect where gas flows naturally.

[0043] Water vapor generated in the hydrogen reaction chamber 10 may condense therein, and the condensed water may flow into the gas mixing device 12 . The gas mixing device 12 is connected to a drain valve 15 for regularly draining the water accumulated in the gas mixing device 12 .

[0044] The hydrogen reaction device is connected to the exhaust gas treatment device, which includes an exhaust gas cooling box 13. The exhaust gas cooling box 13 is provided with cooling water and a cooler 14 for cooling the cooling water. The gas generated in the hydrogen reaction chamber 10 is passed into the exhaust gas cooling box 13 and cooled by the cooling water. The exhaust gas in the exhaust gas cooling box 13 is passed into the gas mixing device 12 for circulation treatment.

[0045] The control method for the small space containment 2 hydrogen risk accident post-processing system of this embodiment includes the following steps:

[0046] Step 1: Open the inert gas supply device 1 and sequentially introduce the inert gas into the gas mixing device 12 through the gas heater 6 and the second valve 7;

[0047] Step 2: Turn on the fan 4, open the third valve 8, and draw air from the atmosphere through the air delivery pipe 5 to the gas mixing device 12;

[0048] Step 3: After the gas transported in steps 1 and 2 is stabilized, the first valve 3 is opened to connect the pipeline between the containment vessel 2 and the gas mixing device 12;

[0049] Step 4: Monitor the hydrogen concentration of the gas mixing device 12 measured by the hydrogen concentration detection device 9, and adjust the opening of the first valve 3 according to the read hydrogen concentration to control the hydrogen concentration of the gas mixing device 12 to be below 3%;

[0050] Step 5: After being mixed in the gas mixing device 12, the mixed gas is introduced into the hydrogen reaction chamber 10. The hydrogen recombiner 11 recombines the hydrogen and oxygen at room temperature to generate water or water vapor. The water vapor condenses on the wall of the hydrogen reaction chamber 10. The condensed water flows to the bottom of the hydrogen reaction chamber 10 and then flows to the gas mixing device 12 located at the bottom of the hydrogen reaction chamber 10.

[0051] Step 6: The combined exhaust gas flows from the hydrogen reaction chamber 10 to the cooling water in the exhaust gas cooling box 13. Water vapor condenses in the cooling water, and the non-condensable gas in the exhaust gas flows to the gas mixing device 12. The cooler 14 is used to cool the cooling water in the exhaust gas cooling box 13 to maintain the cooling water temperature below 50°C.

[0052] Step 7: After the tail gas flows back to the gas mixing device 12, it is mixed with the inert gas from the inert gas supply device 1, the hydrogen from the containment 2 and the air from the air delivery pipe 5, and then continues to enter the hydrogen reaction chamber 10;

[0053] Step 8: Regularly open the drain valve 15 to discharge the wastewater in the gas mixing device 12 into the waste liquid treatment plant;

[0054] Step 9: Repeat steps 5 to 8 until the hydrogen concentration in the containment vessel 2 is less than 0.5%.

[0055] Example 2:

[0056] This embodiment further defines the gas mixing device 12 based on the embodiment 1.

[0057] The gas mixing device 12 includes a gas mixer 121, a gas temporary chamber 122 and a gas storage chamber 123 in sequence. The gas mixer 121 is respectively connected to the inert gas supply device 1, the oxygen supply device and the exhaust gas treatment device, and is used to mix the inert gas, oxygen and exhaust gas; a piston plate 1223 is provided in the gas temporary chamber 122, and a first one-way valve 1222 is provided on the piston plate 1223. The first one-way valve 1222 is placed near the outer periphery of the piston plate 1223. The piston plate 1223 is connected to a linear drive mechanism 1221, which can drive the piston plate 1223 to fit with one end of the gas temporary chamber 122 close to the gas mixer 121, thereby closing the gas mixer 121. The gas temporary chamber 122 is provided with a hydrogen concentration detection device 9. A gas compensation device 124 is also provided between the gas temporary chamber 122 and the gas storage chamber 123. The gas compensation device 124 is respectively connected to the inert gas supply device 1 and the containment shell 2.

[0058] The gas mixer 121 includes a mixer body. The mixer body adopts a tubular structure with a middle cavity. The middle cavity is connected to the inert gas supply device 1. The tube wall of the mixer body is provided with a plurality of spaced annular cavities 1211. The annular cavities 1211 are spaced apart and connected to the oxygen supply device, the tail gas treatment device and the containment shell 2. The annular cavity 1211 is also provided with a plurality of inclined holes to connect the middle cavity. The inert gas is first introduced into the structure of the middle cavity. This is based on the fact that the content of the inert gas is large and can provide the main supply. Then, the various gases connected to the plurality of annular cavities 1211 are then fed into the middle cavity through the inclined holes at a nearly tangential angle, which can form a better mixture with the inert gas. Moreover, the spaced arrangement can make the gas mixing more uniform.

[0059] After the mixed gas enters the gas temporary storage chamber 122, where it briefly remains. After accumulating to a certain amount, the linear drive mechanism 1221 drives the piston plate 1223 to move. The linear drive mechanism 1221 in this embodiment uses a motor-driven screw reciprocating mechanism to drive the piston plate 1223 to move. The piston plate 1223 is also equipped with several guide rods to ensure smooth linear movement. The mixed gas passes through the first one-way valve 1222 on the piston plate 1223 and reaches the other side of the piston plate 1223. At this time, the hydrogen concentration in the mixed gas is detected by the hydrogen concentration detection device 9. The tail gas is mixed with the mixed gas, and the hydrogen concentration in the tail gas is uncertain, resulting in the hydrogen concentration being unstable after mixing. The method of controlling the valve opening of the containment shell 2 has the problem of slow response. Therefore, the present embodiment accurately measures the hydrogen concentration by storing the mixed gas in the gas temporary storage chamber 122, which has a higher measurement accuracy. When the measured hydrogen concentration exceeds 3%, the gas compensation device 124 is required to supplement a portion of inert gas to reduce the hydrogen concentration and ensure the safety of the reaction; when the measured hydrogen concentration is lower than 2%, the gas compensation device 124 is required to supplement a portion of hydrogen to increase the hydrogen concentration and improve the efficiency of the reaction.

[0060] The gas compensation device 124 includes a connecting pipe, which is provided with an air inlet 1243 along the radial direction for connecting the inert gas supply device 1 and the containment shell 2. The connecting pipe is also provided with a rotating body 1241. An embedded portion is provided at one end of the rotating body 1241, and the embedded portion is provided with a docking hole. The embedded portion can be inserted into the air inlet 1243 so that the docking hole and the air inlet 1243 are docked. The rotating body 1241 is connected to a rotary drive mechanism 1242. The rotary drive mechanism 1242 can drive the rotating body 1241 to rotate, so that the docking hole of the rotating body 1241 can switch between the air inlet 1243 of the inert gas supply device 1, the air inlet 1243 of the containment shell 2, and a non-docking hole position. The rotary drive mechanism 1242 uses a motor, gears, and a ring gear arranged on the rotating body 1241. The motor output drives the gear to rotate, and the rotation of the gear drives the ring gear and the rotating body 1241 to rotate.

[0061] A valve plate is also provided in the middle of the connecting pipe, on which a second one-way valve 1244 is provided. The air inlet 1243 of the inert gas supply device 1 and the air inlet 1243 of the containment shell 2 are both located on the side of the second one-way valve 1244 close to the gas temporary storage chamber 122 .

[0062] The first one-way valve 1222 and the second one-way valve 1244 are both constructed by combining a plurality of conical plates, and the backs of the conical plates are connected to elastic supporting components, such as springs.

[0063] When the compensating gas enters the connecting pipe, the piston plate 1223, driven by the linear drive mechanism 1221, returns to compression and presses the mixed gas into the gas storage chamber 123. At this time, the gas passing through the second one-way valve 1244 forms a short high pressure due to the small pipe diameter, which can bring the compensating gas into the gas storage chamber and enter a mixed state at the same time.

Claims

1. A post-processing system for hydrogen risk accidents in small space containment, characterized by: The invention comprises an inert gas supply device, an oxygen supply device, a gas mixing device, a hydrogen reaction device, an exhaust gas treatment device and a processor. The inert gas supply device, the oxygen supply device and the containment shell are respectively connected to the gas mixing device. A first valve is provided between the containment shell and the gas mixing device. A hydrogen concentration detection device is provided in the gas mixing device. The hydrogen concentration detection device and the first valve are both connected to the processor. The processor can control the opening of the first valve according to the hydrogen concentration detected by the hydrogen concentration detection device so that the hydrogen concentration in the gas mixing device is lower than the set value; the gas mixing device is connected to the hydrogen reaction device, and the hydrogen reaction device is connected to the exhaust gas treatment device.

2. The post-processing system for hydrogen risk accidents in small space containment according to claim 1 is characterized in that: A gas heater is further connected between the inert gas supply device and the gas mixing device.

3. The post-processing system for hydrogen risk accidents in small space containment according to claim 1 is characterized in that: The oxygen supply device includes a blower connected to an air delivery pipe, and the blower is connected to the gas mixing device.

4. The post-processing system for hydrogen risk accidents in small space containment according to claim 1 is characterized in that: The hydrogen reaction device comprises a hydrogen reaction chamber, in which a hydrogen recombiner is arranged.

5. The post-processing system for hydrogen risk accidents in small space containment according to claim 1 is characterized in that: The tail gas treatment device includes a tail gas cooling box, in which cooling water and a cooler for cooling the cooling water are arranged, and the tail gas in the tail gas cooling box is passed into the gas mixing device.

6. A post-processing system for hydrogen risk accidents in small space containment, characterized in that: The system comprises an inert gas supply device, an oxygen supply device, a gas mixing device, a hydrogen reaction device, an exhaust gas treatment device and a processor. The inert gas supply device, the oxygen supply device and the containment shell are respectively connected to the gas mixing device, the gas mixing device is connected to the hydrogen reaction device, the hydrogen reaction device is connected to the exhaust gas treatment device, and the exhaust gas treatment device is further connected to the gas mixing device. Among them, the gas mixing device includes a gas mixer, a gas temporary chamber and a gas storage chamber in sequence. The gas mixer is respectively connected to the inert gas supply device, the oxygen supply device and the exhaust gas treatment device, and is used to mix the inert gas, oxygen and exhaust gas; a piston plate is provided in the gas temporary chamber, and a first one-way valve is provided on the piston plate. The first one-way valve is placed near the outer periphery of the piston plate. The piston plate is connected to a linear drive mechanism, which can drive the piston plate to fit with one end of the gas temporary chamber close to the gas mixer, thereby closing the gas mixer. The gas temporary chamber is provided with a hydrogen concentration detection device, and a gas compensation device is also provided between the gas temporary chamber and the gas storage chamber. The gas compensation device is respectively connected to the inert gas supply device and the containment shell.

7. The post-processing system for hydrogen risk accidents in small space containment according to claim 6 is characterized in that: The gas compensation device includes a connecting pipe, the connecting pipe is provided with an air inlet hole connecting the inert gas supply device and the containment shell in a radial direction, the connecting pipe is further provided with a rotating body, one end of the rotating body is provided with an embedded portion, the embedded portion is provided with a docking hole, the embedded portion can be inserted into the air inlet hole so that the docking hole and the air inlet hole are docked, and the rotating body is connected to a rotary drive mechanism, the rotary drive mechanism can drive the rotating body to rotate so that the docking hole of the rotating body can switch between the air inlet hole of the inert gas supply device, the air inlet hole of the containment shell, and a non-docking hole position; A valve plate is also provided in the middle of the connecting pipe, on which a second one-way valve is provided. The air inlet of the inert gas supply device and the air inlet of the containment are both located on the side of the second one-way valve close to the gas temporary storage chamber.

8. The post-processing system for hydrogen risk accidents in small space containment according to claim 7 is characterized in that: The first one-way valve and the second one-way valve both adopt a structure formed by a plurality of conical plates, and the back of the conical plates is connected to an elastic supporting component.

9. The post-processing system for hydrogen risk accidents in small space containment according to claim 6 is characterized in that: The gas mixer includes a mixer body, which adopts a tubular structure with a middle cavity. The middle cavity is connected to the inert gas supply device. A plurality of annular cavities arranged at intervals are provided on the tube wall of the mixer body. The annular cavities are connected to the oxygen supply device, the exhaust gas treatment device and the containment shell at intervals. The annular cavities are also provided with a plurality of inclined holes to connect the middle cavity.

10. The control method for a small space containment hydrogen risk accident post-processing system according to any one of claims 1 to 5, characterized in that: The following steps are involved: Step 1: Turn on the inert gas supply device and introduce the inert gas into the gas mixing device through the gas heater and the second valve in sequence; Step 2: Turn on the fan, open the third valve, and extract air from the atmospheric environment through the air delivery pipe and deliver it to the gas mixing device; Step 3: After the gas transported in steps 1 and 2 is stabilized, the first valve is opened to connect the pipeline between the containment vessel and the gas mixing device; Step 4: monitoring the hydrogen concentration of the gas mixing device measured by the hydrogen concentration detection device, adjusting the opening of the first valve according to the read hydrogen concentration, and controlling the hydrogen concentration of the gas mixing device to be below 3%; Step 5: After being mixed in the gas mixing device, the mixed gas is introduced into the hydrogen reaction chamber. The hydrogen recombiner recombines hydrogen and oxygen at room temperature to produce water or water vapor. The water vapor condenses on the wall of the hydrogen reaction chamber. The condensed water flows to the bottom of the hydrogen reaction chamber and then flows to the gas mixing device located at the bottom of the hydrogen reaction chamber. Step 6: The combined exhaust gas flows from the hydrogen reaction chamber to the cooling water in the exhaust gas cooling box. Water vapor condenses in the cooling water, and the non-condensable gas in the exhaust gas flows to the gas mixing device. The cooler is used to cool the cooling water in the exhaust gas cooling box to maintain the cooling water temperature below 50°C. Step 7: After the tail gas flows back to the gas mixing device, it is mixed with the inert gas from the inert gas supply device, the hydrogen from the containment, and the air from the air delivery pipe, and then continues to enter the hydrogen reaction chamber; Step 8: Open the drain valve regularly to discharge the wastewater from the gas mixing device into the waste liquid treatment plant; Step 9: Repeat steps 5 to 8 until the hydrogen concentration in the containment vessel is less than 0.5%.

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