Containment depressurization system, reactor building and containment depressurization method

Abstract

The invention discloses a containment pressure reduction system, a reactor building and a containment pressure reduction method, which can realize pressure relief of a containment and simplify the structure of the containment pressure reduction system. The containment depressurization system comprises a heat exchange pool and a discharge depressurization loop. The discharge depressurization loop comprises a leading-out pipeline and a flow guide cover. The first end of the leading-out pipeline is communicated with the interior of the containment, and the second end of the leading-out pipeline extends into the heat exchange water tank, is positioned below the liquid level of cooling water in the heat exchange water tank and is used for leading the radioactive gas in the containment into the cooling water in the heat exchange water tank, so that radioactive substances in the radioactive gas are removed through the cooling water. The flow guide cover is arranged over the second end of the guiding-out pipeline in an inverted buckling mode, the top of the flow guide cover is located above the liquid level of cooling water in the heat exchange water pool, the bottom of the flow guide cover is submerged below the liquid level of the cooling water in the heat exchange water pool, and the flow guide cover is used for receiving the gas with the radioactive substances removed.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of nuclear power safety, and particularly relates to a containment depressurization system, a reactor building and a containment depressurization method. BACKGROUND

[0002] In the field of nuclear power design, in order to ensure that the structural strength of the containment can withstand the air pressure in the containment under accident conditions, the design pressure of the containment is usually set according to the peak pressure calculated by accident analysis plus a 10% margin.

[0003] However, the analysis and calculation of the peak pressure are carried out by selecting typical accidents and considering appropriate assumption conditions. In special cases, there is still a possibility that the pressure of radioactive gas in the containment will exceed the design pressure of the containment, leading to a containment accident.

[0004] In the prior art, in order to avoid the pressure of radioactive gas in the containment exceeding its carrying capacity, a set of three or four levels of filtration and discharge systems are generally provided to realize the depressurization of the containment. However, this system has a complex structure, resulting in a large system size, high procurement cost of equipment in the system, and the need to build a supporting concrete building, which has high construction, operation and maintenance costs. SUMMARY

[0005] The technical problem to be solved by the present application is to solve the above-mentioned deficiencies existing in the prior art, and to provide a containment depressurization system, a reactor building and a containment depressurization method, which can realize the depressurization of the containment and simplify the structure of the containment depressurization system.

[0006] In a first aspect, the embodiments of the present application provide a containment depressurization system, which comprises a heat exchange pool and a discharge depressurization circuit. The heat exchange pool is arranged outside the containment and stores cooling water therein. The discharge depressurization circuit comprises a discharge pipeline and a flow guide cover. The first end of the discharge pipeline is in communication with the inside of the containment, and the second end of the discharge pipeline extends into the cooling water in the heat exchange pool below the liquid level of the cooling water in the heat exchange pool, for guiding the radioactive gas in the inside of the containment to the cooling water in the heat exchange pool, so as to remove radioactive substances in the radioactive gas by the cooling water. The flow guide cover is arranged upside down above the second end of the discharge pipeline, the top of the flow guide cover is above the liquid level of the cooling water in the heat exchange pool, and the bottom of the flow guide cover is submerged below the liquid level of the cooling water in the heat exchange pool, for receiving the gas after the removal of radioactive substances; the top of the flow guide cover is provided with an exhaust hole, and the exhaust hole is used for discharging the gas in the flow guide cover to the gas space in the heat exchange pool.

[0007] In some embodiments, the opening of the second end of the discharge pipeline faces upward. The exhaust pressure relief circuit further comprises a sleeve vertically arranged in the cooling water in the heat exchange pool, the lower end of the sleeve is sleeved outside the second end of the discharge pipeline, and the upper end of the sleeve extends into the flow guide cover and is below the liquid level of the cooling water.

[0008] In some embodiments, a plurality of through holes are formed in the side wall of the top of the sleeve.

[0009] In some embodiments, the discharge pipeline comprises a main pipeline and a plurality of branch pipelines; the main pipeline is in communication with the inside of the containment vessel, the plurality of branch pipelines are horizontally submerged below the liquid level of the cooling water in the heat exchange pool and are in communication with the main pipeline; a plurality of exhaust pipes are arranged on each of the branch pipelines, and the pipe openings of the exhaust pipes face upward; the radioactive gas entering the main pipeline is discharged into the cooling water in the heat exchange pool through the plurality of exhaust pipes on the branch pipelines. The number of sleeves is a plurality, and the plurality of sleeves are arranged one-to-one corresponding to the plurality of exhaust pipes, and the lower end of each sleeve is sleeved outside the pipe opening of the corresponding exhaust pipe. The number of flow guide covers is one, and the upper end of each sleeve extends into the flow guide cover and is below the liquid level of the cooling water.

[0010] In some embodiments, the discharge pipeline comprises a main pipeline and a plurality of branch pipelines; the main pipeline is in communication with the inside of the containment vessel, the plurality of branch pipelines are horizontally submerged below the liquid level of the cooling water in the heat exchange pool and are in communication with the main pipeline; a plurality of exhaust pipes are arranged on each of the branch pipelines, and the pipe openings of the exhaust pipes face upward; the radioactive gas entering the main pipeline is discharged into the cooling water in the heat exchange pool through the plurality of exhaust pipes on the branch pipelines. The number of sleeves is a plurality, and the plurality of sleeves are arranged one-to-one corresponding to the plurality of exhaust pipes, and the lower end of each sleeve is sleeved outside the pipe opening of the corresponding exhaust pipe. The number of flow guide covers is a plurality, and the plurality of flow guide covers are arranged one-to-one corresponding to the plurality of branch pipelines, and the upper end of the sleeve corresponding to the plurality of exhaust pipes on the branch pipeline extends into the flow guide cover corresponding to the branch pipeline and is below the liquid level of the cooling water.

[0011] In some embodiments, the containment pressure relief system further comprises a heat conduction pressure relief circuit. The heat conduction pressure relief circuit comprises a heat exchange device arranged inside the containment vessel and connected to the inside of the heat exchange pool through a circulating pipeline, so that the cooling water in the heat exchange pool can circulate between the heat exchange pool and the heat exchange device, and the heat in the containment vessel is discharged into the heat exchange pool through the circulation of the cooling water.

[0012] In some embodiments, the containment depressurization system further includes a waste liquid return pipeline. The waste liquid return pipeline includes a drain pipe, one end of which is connected to the bottom of the hot water exchange tank, and the other end of which is connected to the interior of the containment, for discharging cooling water from the hot water exchange tank that has absorbed radioactive substances from the radioactive gas into the containment.

[0013] In some embodiments, the containment depressurization system further includes a control component. The control component includes a barometer, a controller, a first shut-off valve, a second shut-off valve, and a third shut-off valve. The barometer is disposed within the containment and is used to acquire the real-time air pressure within the containment. The controller is electrically connected to the barometer and is used to acquire the real-time air pressure and control the first, second, and third shut-off valves based on the real-time air pressure. The first shut-off valve is disposed on the outlet pipe of the discharge depressurization circuit and is electrically connected to the controller, used to control the opening and closing of the outlet pipe under the control of the controller. The second shut-off valve is disposed on the circulation pipe of the heat conduction depressurization circuit and is electrically connected to the controller, used to control the opening and closing of the circulation pipe under the control of the controller. The third shut-off valve is disposed on the drain pipe of the waste liquid return line and is electrically connected to the controller, used to control the opening and closing of the drain pipe under the control of the controller.

[0014] Therefore, the containment depressurization system provided in this embodiment of the invention, by setting up a hot water exchange tank and an outlet pipe, with the first end of the outlet pipe connected to the interior of the containment and the second end of the outlet pipe extending into the hot water exchange tank and located below the cooling water surface in the hot water exchange tank, can export the high-temperature, high-pressure radioactive gas inside the containment to the cooling water in the hot water exchange tank after a containment accident, and remove the radioactive substances from the radioactive gas through the cooling water, retaining the radioactive substances in the cooling water in the hot water exchange tank; by setting up a guide shroud and placing the guide shroud upside down directly above the second end of the outlet pipe. The top of the deflector is positioned above the cooling water surface in the hot water exchange tank, while the bottom is submerged below. The deflector prevents radioactive gas ejected from the second end of the outlet pipe from breaking through the cooling water and directly entering the gas space within the hot water exchange tank. It also performs gas-liquid separation on the gas entering the deflector to remove water mist, thereby reducing the amount of water mist discharged into the gas space within the hot water exchange tank. This prevents reflective substances trapped in the water mist from entering the gas space, thus retaining more radioactive material in the cooling water of the hot water exchange tank. In summary, the containment depressurization system in this embodiment can discharge radioactive gas from the containment to relieve pressure on the containment and retain radioactive material in the cooling water of the hot water exchange tank, achieving the goal of reducing or preventing the release of radioactive material into the external environment. Furthermore, this containment depressurization system has a simple structure, simplifying the overall design of containment depressurization systems.

[0015] In a second aspect, the embodiments of the present application further provide a reactor building, which comprises a containment and the containment depressurization system in the first aspect. The containment is internally provided with a loop system.

[0016] In a third aspect, the embodiments of the present application further provide a containment depressurization method, which uses the containment depressurization system in the first aspect, and the method comprises: monitoring a real-time air pressure in the containment; comparing the real-time air pressure with a first threshold air pressure to obtain a first comparison result, and if the first comparison result is that the real-time air pressure is greater than the first threshold air pressure, then the radioactive gas in the containment is guided out to the cooling water in the heat exchange pool through the guide-out pipeline, so as to remove the radioactive substances in the radioactive gas by the cooling water.

[0017] In some embodiments, in the case that the containment depressurization system comprises the heat-conducting depressurization loop. After the real-time air pressure in the containment is monitored, and before the real-time air pressure is compared with the first threshold air pressure to obtain the first comparison result, the method further comprises: comparing the real-time air pressure with a second threshold air pressure to obtain a second comparison result, and if the second comparison result is that the real-time air pressure is greater than the second threshold air pressure, then the cooling water in the heat exchange pool is enabled to circulate between the heat exchange pool and the heat exchange device through the circulating pipeline, and the heat in the containment is guided out to the heat exchange pool through the circulation of the cooling water; wherein the second threshold air pressure is less than the first threshold air pressure.

[0018] In some embodiments, in the case that the containment depressurization system comprises the waste liquid return pipeline. After the radioactive gas in the containment is guided out to the cooling water in the heat exchange pool through the guide-out pipeline, the method further comprises: discharging the cooling water in the heat exchange pool after absorbing the radioactive substances in the radioactive gas to the containment through the liquid discharge pipeline.

[0019] The reactor building and the containment depressurization method provided by the embodiments of the present application have the same beneficial effects as the above-mentioned containment depressurization system, and will not be described here. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 FIG. 1 is a structural diagram of a reactor building provided by an embodiment of the present application;

[0021] Figure 2 FIG. 2 is a structural diagram of a fairing and a sleeve provided by an embodiment of the present application;

[0022] Figures 3-6 FIG. 3 is a schematic diagram of a first fairing, a branch pipe and an exhaust pipe arrangement provided by an embodiment of the present application;

[0023] Figures 7-10 : the second kind of fairing, branch pipe and exhaust pipe arrangement provided for the embodiment of the present application;

[0024] Figures 11-12 : the third kind of fairing, branch pipe and exhaust pipe arrangement provided for the embodiment of the present application.

[0025] 1-heat exchange pool; 2-safety shell; 3-lead-out pipe; 4-fairing; 5-sleeve; 6-main pipe; 7-branch pipe; 8-exhaust pipe; 9-heat exchange device; 10-circulation pipe;

[0026] 11-drainage pipe; 12-first stop valve; 13-second stop valve; 14-third stop valve;

[0027] 15-air valve. DETAILED DESCRIPTION

[0028] In order for those skilled in the art to better understand the technical solutions of the present application, the present application will be further described in detail below in combination with the drawings and embodiments.

[0029] Embodiment 1:

[0030] As shown in Figure 1 and Figure 2 , the present application provides a safety shell pressure reduction system, which is applied to a reactor building and used for depressurizing a reactor.

[0031] As shown in Figure 1 and Figure 2 , the safety shell pressure reduction system comprises a heat exchange pool 1 and a discharge pressure reduction circuit. The heat exchange pool 1 is arranged outside the safety shell 2 and stores cooling water therein. The discharge pressure reduction circuit comprises a lead-out pipe 3 and a fairing 4. The first end of the lead-out pipe 3 is in communication with the inside of the safety shell 2, and the second end of the lead-out pipe 3 extends into the heat exchange pool 1 and is below the liquid level of the cooling water in the heat exchange pool 1, for leading radioactive gas (usually including gaseous components, radioactive aerosols and radioactive elemental particles) in the safety shell 2 to the cooling water in the heat exchange pool 1, so as to remove radioactive substances in the radioactive gas by the cooling water. The fairing 4 is arranged upside down above the second end of the lead-out pipe 3, the top of the fairing 4 is above the liquid level of the cooling water in the heat exchange pool 1, and the bottom of the fairing 4 is submerged below the liquid level of the cooling water in the heat exchange pool 1, for receiving the gas after the removal of radioactive substances; the top of the fairing 4 is provided with an exhaust hole for discharging the gas in the fairing 4 to the gas space in the heat exchange pool 1.

[0032] Exemplarily, the heat exchange pool 1 can also be a heat exchange tank, which can be arranged on the outer surface of the containment 2. The heat exchange pool 1 can contain 1500 cubic meters of cooling water. The cooling water in the heat exchange pool 1 does not fill the entire heat exchange pool 1, and part of the gas space is reserved in the heat exchange pool 1. As shown in Figure 1 The top of the heat exchange pool 1 is provided with an air valve 15, which is normally closed. When the air valve 15 is opened, the gas space in the heat exchange pool 1 is in communication with the external atmosphere.

[0033] Exemplarily, the air valve 15 can be connected with a temperature control switch, which is arranged at the top of the heat exchange pool 1. The temperature control switch is used to open the air valve 15 when the temperature of the gas in the heat exchange pool 1 is sensed to be increased to 80°C.

[0034] The materials of the discharge pipeline 3 and the flow guide cover 4 can be stainless steel. The discharge pipeline 3 and the flow guide cover 4 can be fixed on the side wall of the heat exchange pool 1.

[0035] Exemplarily, as shown in Figure 1 The first end of the discharge pipeline 3 penetrates the side wall of the containment 2 and extends into the containment 2. The second end of the discharge pipeline 3 can penetrate the side wall of the heat exchange pool 1 and extend into the heat exchange pool 1, or can penetrate the top wall of the heat exchange pool 1 and extend into the heat exchange pool 1.

[0036] Exemplarily, the shape of the flow guide cover 4 can be cylindrical.

[0037] When the containment vessel is caused to have a temperature rise (e.g. to 150℃) and a pressure rise (e.g. to 0.52 MPa, the pressure values herein are absolute pressure values) due to an accident, the high-temperature and high-pressure radioactive gas in the containment vessel can be guided out through the guide-out pipe 3 to the cooling water inside the heat exchange pool 1, the heat in the containment vessel can be guided out to the cooling water, and the radioactive substances (e.g. including radioactive aerosols and radioactive elements) in the radioactive gas can also be dissolved by the cooling water and retained in the cooling water, the gas (e.g. including gas components and water vapor) after removal of the radioactive substances rises into the flow guide cover 4 and is discharged from the exhaust hole at the top of the flow guide cover 4 to the gas space inside the heat exchange pool 1, and when the air valve 15 at the top of the heat exchange pool 1 is opened, the gas in the gas space inside the heat exchange pool 1 is discharged to the atmosphere. The flow guide cover 4 can also prevent the radioactive gas sprayed from the second end of the guide-out pipe 3 from penetrating the cooling water and being directly sprayed into the gas space inside the heat exchange pool 1, thereby avoiding the radioactive substances in the radioactive gas from being retained by the cooling water and entering the gas space inside the heat exchange pool 1 and then being discharged to the outside atmosphere; on the other hand, the flow guide cover 4 can also play a role in gas-liquid separation, so that the water mist in the gas entering the flow guide cover 4 is retained in the flow guide cover 4 after colliding with the inner wall of the flow guide cover 4, thereby reducing the water mist discharged by the flow guide cover 4 to the gas space inside the heat exchange pool 1, so as to avoid the reflective substances retained in the water mist from entering the gas space inside the heat exchange pool 1, thereby retaining more radioactive substances in the cooling water inside the heat exchange pool 1, and further reducing the amount of radioactive substances discharged to the external environment.

[0038] Therefore, through the above arrangement, the radioactive gas in the containment vessel can be guided out to depressurize the containment vessel, and the radioactive substances in the radioactive gas can be removed by the cooling water in the heat exchange pool 1, and the flow guide cover 4 reduces the water mist discharged to the external air to avoid the water mist with radioactive substances from being discharged, thereby achieving the purpose of avoiding the radioactive substances from being discharged to the external environment. Moreover, the containment vessel depressurization system provided by the embodiment of the present application has a simple structure and can reduce the construction, operation and maintenance costs of the containment vessel depressurization system.

[0039] Thus, the containment pressure relief system provided by the embodiment of the present application can, after an accident of the containment 2, guide the high-temperature and high-pressure radioactive gas in the containment 2 to the cooling water in the heat exchange pool 1, and remove the radioactive substances in the radioactive gas through the cooling water, so as to retain the radioactive substances in the cooling water in the heat exchange pool 1; the flow guide cover 4 is arranged upside down above the second end of the guide-out pipeline 3, the top of the flow guide cover 4 is above the liquid level of the cooling water in the heat exchange pool 1, and the bottom of the flow guide cover 4 is submerged below the liquid level of the cooling water in the heat exchange pool 1, so that the flow guide cover 4 prevents the radioactive gas sprayed from the second end of the guide-out pipeline 3 from directly spraying into the gas space in the heat exchange pool 1 by breaking through the cooling water, and separates the gas and liquid to remove the water mist in the gas, so as to reduce the water mist discharged by the flow guide cover 4 into the gas space in the heat exchange pool 1, avoid the reflective substances retained in the water mist from entering the gas space in the heat exchange pool 1, and thus retain more radioactive substances in the cooling water in the heat exchange pool 1.

[0040] In summary, the containment pressure relief system in the embodiment of the present application can guide the radioactive gas in the containment 2 to relieve the pressure of the containment 2, and retain the radioactive substances in the radioactive gas in the cooling water in the heat exchange pool 1, so as to reduce or avoid the radioactive substances from being discharged into the external environment. Moreover, the containment pressure relief system has a simple structure, and simplifies the structure of the containment pressure relief system.

[0041] In some embodiments, the guide-out pipeline 3 is internally provided with radioactive adsorption substances, such as sodium hydroxide, sodium thiosulfate, etc.

[0042] When the radioactive gas is guided out of the containment to the heat exchange pool 1, the radioactive gas will carry the radioactive adsorption substances to the cooling water in the heat exchange pool 1, and the radioactive adsorption substances dissolved in the cooling water can react with the radioactive substances absorbed in the cooling water, so as to increase the retention effect of the cooling water in the heat exchange pool 1 on the radioactive substances.

[0043] In some embodiments, as shown in Figure 2 the opening of the second end of the guide-out pipeline 3 faces upward. The discharge pressure relief circuit further comprises a sleeve 5 vertically arranged in the cooling water in the heat exchange pool 1, the lower end of the sleeve 5 is sleeved outside the second end of the guide-out pipeline 3, and the upper end of the sleeve 5 extends into the flow guide cover 4 and is below the liquid level of the cooling water.

[0044] For example, the opening of the second end of the guide-out pipeline 3 is provided with a spray head.

[0045] The material of the sleeve 5 can be stainless steel, and the sleeve 5 can be fixed on the outlet pipe 3.

[0046] As shown in Figure 2 The second end of the outlet pipe 3 sprays radioactive gas into the cooling water in the heat exchange pool 1 to form a jet, and the cooling water in the sleeve 5 continuously overflows from the top end of the sleeve 5, while the cooling water in the heat exchange pool 1 will flow into the sleeve 5 from the bottom end of the sleeve 5 to replenish the overflow and evaporation loss in the sleeve 5, finally achieving replacement of the cooling water containing radioactive substances in the sleeve 5, reducing the concentration of radioactive substances in the sleeve 5, and further improving the retention efficiency of radioactive substances.

[0047] By setting the sleeve 5, the jet formed by the radioactive gas can be limited in the sleeve 5, and the pressure fluctuation caused by the jet formed by the radioactive gas is also limited in the sleeve 5, blocking the propagation of the pressure fluctuation to the surrounding. In the process of releasing the heat of the radioactive gas in the containment 2 to the cooling water in the heat exchange pool 1, the latent heat release of the steam (water vapor) in the radioactive gas accounts for 85% of the overall energy release. By limiting the jet formed by the radioactive gas in the sleeve 5, the temperature of the cooling water in the sleeve 5 will rapidly rise to the saturation temperature under this state when the radioactive gas is discharged, at which time the steam in the radioactive gas only releases superheat and will not condense due to the rapid temperature drop, thereby avoiding the release of latent heat in the condensation process and effectively avoiding the rapid rise of the temperature of the cooling water in the heat exchange pool 1.

[0048] As shown in Figure 2 A plurality of through holes are formed in the side wall of the top of the sleeve 5.

[0049] Exemplarily, the plurality of through holes are uniformly distributed along the circumferential direction of the side wall of the sleeve 5.

[0050] The gas flow rate discharged through these small holes is higher, and the water mist therein is more likely to hit the side wall of the flow guide cover 4 to form liquid droplets falling back into the cooling water, which is more conducive to gas-liquid separation at the outlet of the top of the sleeve 5, and can as much as possible return the water mist containing radioactive substances to the cooling water in the heat exchange pool 1, avoiding the radioactive substances retained in the water mist from being finally discharged to the external environment.

[0051] When the total amount of radioactive gas to be discharged in the containment vessel is large, if the radioactive gas is discharged from one outlet, the radioactive material in the radioactive gas may not be effectively retained and discharged into the flow guide cover 4 due to the excessive flow of the radioactive gas, affecting the retention efficiency of the radioactive material in the radioactive gas by the cooling water, at which time the structure and arrangement of the discharge pipe 3, the flow guide cover 4 and the sleeve pipe 5 need to be reasonably set. The present inventors have studied the jet flow pattern and retention efficiency under different structures and arrangements of the discharge pipe 3, the flow guide cover 4 and the sleeve pipe 5 through experiments, and propose the structure and arrangement of the discharge pipe 3, the flow guide cover 4 and the sleeve pipe 5 in the following embodiments.

[0052] In some embodiments, as shown in Figures 3-6 , the discharge pipe 3 comprises a main pipe 6 and a plurality of branch pipes 7; the main pipe 6 is in communication with the inside of the containment vessel 2, and the plurality of branch pipes 7 are horizontally immersed below the cooling water liquid level in the heat exchange pool 1 and are in communication with the main pipe 6; a plurality of exhaust pipes 8 are arranged on each branch pipe 7, and the pipe openings of the exhaust pipes 8 are upward; the radioactive gas entering the main pipe 6 is discharged into the cooling water in the heat exchange pool 1 through the plurality of exhaust pipes 8 on the branch pipes 7. The number of sleeve pipes 5 is multiple, and the plurality of sleeve pipes 5 are arranged one by one corresponding to the plurality of exhaust pipes 8, and the lower end of each sleeve pipe 5 is sleeved outside the pipe opening of the corresponding exhaust pipe 8. The number of flow guide covers 4 is one, and the upper ends of all sleeve pipes 5 extend into the flow guide cover 4 and are below the cooling water liquid level.

[0053] It should be noted that, Figures 3-12 all are schematic diagrams, and the sleeve pipes 5 are not shown in the drawings.

[0054] For example, the number of branch pipes 7 can be two, three or five, etc.

[0055] For example, Figure 3 and Figure 5 two branch pipes 7 are shown in Figure 3 , the downward arrow in indicates the flow direction of the radioactive gas in the main pipe 6. The branch pipes 7 are arranged on opposite sides of the main pipe 6, respectively.

[0056] In combination with Figure 3 and Figure 4 , at this time the flow guide cover 4 and the branch pipe 7 are arranged at the side wall of the heat exchange pool 1, which can facilitate the installation of the flow guide cover 4 and the branch pipe 7.

[0057] For example, as shown in Figure 6 , the exhaust pipes 8 are arranged in two rows and are uniformly distributed on each branch pipe 7.

[0058] For example, in combination with Figure 4 and Figure 6The dimensions of the fairing 4 are 12000mm × 400mm, the inner diameter of the exhaust pipe 8 is 8mm, and the adjacent exhaust pipe 8 ( Figure 6 The longitudinal spacing (indicated by black dots) is 200mm, and the transverse spacing is 250mm. Verification has shown that this spacing avoids interference between the jets of radioactive gas emitted from adjacent exhaust pipes 8, and keeps the flow velocity of the radioactive gas from exhaust pipe 8 within a reasonable range, preventing the radioactive gas from breaking through the cooling water surface. At this time, if... Figure 6 As shown, 16 exhaust pipes 8 can be evenly distributed over a distance of 2000mm, so 96 exhaust pipes 8 can be evenly arranged within the entire fairing 4.

[0059] In this example, the deflector 4 and branch pipe 7 are installed on the side wall of the heat exchange tank 1. All the gas emitted from the branch pipe 7 can be collected and discharged by a single deflector 4, facilitating gas collection. Furthermore, this design concentrates the deflector 4 and branch pipe 7 on the side wall, reducing the overall footprint of the containment depressurization system within the heat exchange tank 1. The gas collected by the deflector 4 is discharged into the gas space within the heat exchange tank 1 through two exhaust ports at the top of the deflector 4. Figure 3 The upward arrow indicates the direction of gas flow from the deflector 4.

[0060] In another example, such as Figures 7-10 As shown, in another configuration of the fairing 4, branch pipes 7, and exhaust pipe 8, the fairing 4 is cylindrical, and there are six branch pipes 7 extending outward from the center of the fairing 4, with an included angle of 60° between adjacent branch pipes 7. The diameter of the fairing 4 is 2500 mm, and the inner diameter of the exhaust pipe 8 is 8 mm. Figure 10 As shown, on each branch pipe 7, two, four, four, and six exhaust pipes 8 are distributed sequentially in the direction away from the center. Figure 10 (Indicated by black dots), that is, each branch pipe 7 has a total of 16 exhaust pipes 8, and the six branch pipes 7 have a total of 96 exhaust pipes 8.

[0061] In this example, radioactive gas can be evenly distributed from the main pipe 6 to each branch pipe 7. Figure 7 The downward arrow indicates the airflow direction in the main pipe 6, making the flow rate of radioactive gas discharged from each exhaust pipe 8 more uniform. The gas collected by the guide shroud 4 is discharged into the gas space inside the hot water exchange tank 1 through a horizontally set exhaust hole at the top of the guide shroud 4. Figure 7 The horizontal arrow in the image indicates the direction of the airflow exiting from the deflector 4.

[0062] In other embodiments, such as Figure 11 and Figure 12As shown, there are multiple flow guides 4, and multiple flow guides 4 are set one-to-one with multiple branch pipes 7. The upper ends of the sleeves 5, which are set corresponding to multiple exhaust pipes 8 on a branch pipe 7, all extend into the flow guide 4 corresponding to that branch pipe 7 and are below the cooling water level.

[0063] For example, such as Figure 11 and Figure 12 As shown, the main pipe 6 and the branch pipe 7 can also be connected by a transition pipe. Figure 11 The downward arrow indicates the direction of radioactive gas flow in main pipe 6. Figure 11 The upward arrow indicates the direction of gas flow from the deflector 4.

[0064] Figure 11 and Figure 12 In the middle, there are two branch pipes 7 and two flow guides 4. Each flow guide 4 is used to collect the gas discharged from the exhaust pipe 8 on the corresponding branch pipe 7.

[0065] With the above settings, the configuration and size of the branch pipe 7 and the exhaust pipe 8 can be flexibly set according to the amount of radioactive gas that the containment 2 needs to discharge. On the one hand, it can prevent the cooling water in the sleeve 5 from being quickly evaporated, and on the other hand, it can ensure that the solution that absorbs radioactive substances in the sleeve 5 can be carried out of the sleeve 5, thereby realizing the replacement of the cooling water in the sleeve 5.

[0066] In some embodiments, a hydrogen elimination device may be provided within the containment, before the inlet of the outlet pipe 3.

[0067] In some embodiments, such as Figure 1 As shown, the containment depressurization system also includes a heat-conducting depressurization circuit. The heat-conducting depressurization circuit includes a heat exchanger 9, which is located inside the containment 2 and is connected to the interior of the heat exchange tank 1 through a circulation pipe 10, so that the cooling water in the heat exchange tank 1 can circulate between the heat exchange tank 1 and the heat exchanger 9, and the heat inside the containment 2 is transferred to the heat exchange tank 1 through the circulation of the cooling water.

[0068] For example, the heat exchange device 9 can be a general plate heat exchanger or a shell and tube heat exchanger.

[0069] For example, the circulation pipe 10 includes a first pipe and a second pipe. The first pipe connects the inlet of the hot water exchange tank 1 and the heat exchange device 9, and the second pipe connects the outlet of the hot water exchange tank 1 and the heat exchange device 9.

[0070] When high-temperature gas is generated in the containment vessel 2 due to an accident, the high-temperature gas warms up the cooling water in the heat exchange device 9, and the cooling water in the heat exchange device 9 and the cooling water in the heat exchange pool 1 circulate due to the temperature difference. Further, a circulating pump can also be arranged on the circulating pipeline 10 to drive the cooling water in the heat exchange device 9 and the cooling water in the heat exchange pool 1 to circulate.

[0071] Through the above arrangement, the heat in the containment vessel 2 can be taken away by the circulation of the cooling water, the temperature in the containment vessel 2 is reduced, and the air pressure in the containment vessel 2 is further reduced to achieve pressure relief in the containment vessel 2.

[0072] In some embodiments, as shown in Figure 1 The containment vessel pressure relief system further includes a waste liquid return pipeline. The waste liquid return pipeline includes a liquid discharge pipeline 11, one end of the liquid discharge pipeline 11 is in communication with the bottom of the heat exchange pool 1, and the other end is in communication with the inside of the containment vessel 2, and is used to discharge the cooling water in the heat exchange pool 1 after absorbing radioactive substances in radioactive gas into the containment vessel 2.

[0073] It can be understood that after the cooling water in the heat exchange pool 1 absorbs radioactive substances, the cooling water in the heat exchange pool 1 is radioactive. Through the above arrangement, the cooling water in the heat exchange pool 1 after absorbing radioactive substances in radioactive gas can be discharged into the containment vessel 2 for treatment, so as to avoid the release of the radioactive cooling water to the external environment.

[0074] In some embodiments, the containment vessel pressure relief system further includes a control assembly. The control assembly includes a pressure gauge, a controller, a first shut-off valve 12, a second shut-off valve 13, and a third shut-off valve 14. The pressure gauge is arranged in the containment vessel 2 and is used to obtain the real-time air pressure in the containment vessel 2. The controller is electrically connected with the pressure gauge and is used to obtain the real-time air pressure and control the first shut-off valve 12, the second shut-off valve 13, and the third shut-off valve 14 according to the real-time air pressure. The first shut-off valve 12 is arranged on the discharge pipeline 3 of the pressure relief circuit and is electrically connected with the controller, and is used to control the opening and closing of the discharge pipeline 3 under the control of the controller. The second shut-off valve 13 is arranged on the circulating pipeline 10 of the heat conduction pressure relief circuit and is electrically connected with the controller, and is used to control the opening and closing of the circulating pipeline 10 under the control of the controller. The third shut-off valve 14 is arranged on the liquid discharge pipeline 11 of the waste liquid return pipeline and is electrically connected with the controller, and is used to control the opening and closing of the liquid discharge pipeline 11 under the control of the controller.

[0075] For example, the controller can be a general programmable logic controller, such as a programmable logic controller produced by Siemens Company with a model number of S7-200.

[0076] For example, the first shut-off valve 12, the second shut-off valve 13, and the third shut-off valve 14 can all be electrically controlled valves. As Figure 1As shown, the number of the first stop valves 12 can be two, and the two first stop valves 12 are respectively arranged on the inner and outer sides of the containment vessel 2; the number of the second stop valves 13 is two, and the two second stop valves 13 are respectively arranged on two sections of the circulating pipeline 10 (for example, the first pipeline and the second pipeline mentioned above). The number of the third stop valves 14 is two, and the two third stop valves 14 are respectively arranged on the inner and outer sides of the containment vessel 2.

[0077] For example, the design pressure of the containment vessel 2 is 0.52 MPa, and the ultimate bearing capacity of the containment vessel is 0.77 MPa. When the pressure gauge monitors that the real-time pressure in the containment vessel 2 is 0.24 MPa, the controller controls the second stop valve 13 to open, and the heat-conducting pressure relief circuit starts to work, and the heat in the containment vessel 2 is taken away by the circulating cooling water to reduce the temperature and pressure in the containment vessel 2, thereby depressurizing the containment vessel 2. If the pressure gauge monitors that the real-time pressure in the containment vessel 2 continues to rise to 0.52 MPa, the controller controls the first stop valve 12 to open, and the discharge pressure relief circuit starts to work, and the radioactive gas in the containment vessel 2 is discharged through the discharge pipeline 3, so as to continue to depressurize the containment vessel 2. When the pressure gauge monitors that the real-time pressure in the containment vessel 2 falls to 0.31 MPa, the controller closes the first stop valve 12, and at this time, only the heat-conducting pressure relief circuit is used to depressurize the containment vessel. If the pressure gauge monitors that the real-time pressure in the containment vessel 2 is reduced to 0.1 MPa, it indicates that the containment vessel 2 has been depressurized, and the controller controls the third stop valve 14 to open, and the waste liquid return pipeline starts to work, and the cooling water in the heat exchange pool 1 after absorbing radioactive substances is discharged into the containment vessel 2.

[0078] Through the above arrangement, the automatic control of the first stop valve 12, the second stop valve 13 and the third stop valve 14 can be realized.

[0079] In some examples, the controller can also realize the control of the first stop valve 12, the second stop valve 13 and the third stop valve 14 under the operation of the operator, so that the operator can realize the control of the first stop valve 12, the second stop valve 13 and the third stop valve 14 in the remote master control room.

[0080] In some embodiments, the number of the heat exchange pool 1, the discharge pressure relief circuit, the heat-conducting pressure relief circuit and the waste liquid return pipeline is multiple, and they are arranged one by one.

[0081] For example, Figure 1 In the embodiment, the number of the heat exchange pool 1, the discharge pressure relief circuit, the heat-conducting pressure relief circuit and the waste liquid return pipeline is two.

[0082] Through the above arrangement, the depressurization capacity of the containment vessel depressurization system to the containment vessel 2 can be improved.

[0083] Embodiment 2:

[0084] The embodiment of the present application also provides a reactor building, which can be a reactor building in a nuclear power plant, and the reactor building comprises a containment 2 and the containment depressurization system in the embodiment 1. The containment 2 is internally provided with a loop system.

[0085] The containment depressurization system can depressurize the containment 2 in the case of an accident of the containment 2, avoid overpressure of the containment 2, improve the safety of the containment 2, and further improve the safety of the reactor building, and reduce the emission of radioactive substances into the external environment when the containment 2 is depressurized.

[0086] Embodiment 3:

[0087] The embodiment of the present application also provides a containment depressurization method, which uses the containment depressurization system in the embodiment 1, and the method comprises the following steps: S100-S200.

[0088] S100, monitoring the real-time air pressure of the atmosphere in the containment 2.

[0089] For example, the containment 2 is internally provided with an air pressure gauge, and the real-time air pressure of the atmosphere in the containment 2 is monitored by the air pressure gauge.

[0090] S200, comparing the real-time air pressure with a first threshold air pressure to obtain a first comparison result, and if the first comparison result is that the real-time air pressure is greater than the first threshold air pressure, then the radioactive gas in the containment 2 is guided out into the cooling water in the heat exchange pool 1 through the guide pipeline 3, so that the radioactive substances in the radioactive gas are removed by the cooling water.

[0091] For example, the first threshold air pressure can be set according to the limit bearing capacity of the containment 2 and the site conditions.

[0092] For example, when the limit bearing capacity of the containment 2 is 0.77Mpa, the first threshold air pressure can be set to 0.52Mpa.

[0093] In this case, when the real-time air pressure of the atmosphere in the containment 2 is greater than 0.52Mpa, the radioactive gas in the containment 2 is guided out into the cooling water in the heat exchange pool 1 through the guide pipeline 3, and the radioactive substances in the radioactive gas are retained in the cooling water, thereby depressurizing the containment 2.

[0094] In some embodiments, in the case that the containment depressurization system comprises a heat conduction depressurization loop. After monitoring the real-time air pressure in the containment 2, before comparing the real-time air pressure with the first threshold air pressure to obtain a first comparison result, the method further comprises: comparing the real-time air pressure with a second threshold air pressure to obtain a second comparison result, if the second comparison result is that the real-time air pressure is greater than the second threshold air pressure, enabling the cooling water in the heat exchange pool 1 to circulate between the heat exchange pool 1 and the heat exchange device 9 through the circulating pipeline 10, and conducting the heat in the containment 2 to the heat exchange pool 1 through the circulation of the cooling water; wherein the second threshold air pressure is less than the first threshold air pressure.

[0095] For example, the second threshold air pressure can be set according to the ultimate bearing capacity of the containment 2 and the first threshold air pressure.

[0096] For example, when the ultimate bearing capacity of the containment 2 is 0.77Mpa and the first threshold air pressure is 0.52Mpa, the second threshold air pressure is 0.24Mpa.

[0097] In this case, when the real-time air pressure in the containment 2 is greater than 0.24Mpa, the heat conduction depressurization loop first starts to work, and the heat in the containment 2 is conducted to the heat exchange pool 1 through the circulation of the cooling water in the circulating pipeline 10, thereby reducing the temperature of the atmosphere in the containment 2 and achieving the depressurization of the containment 2. If the heat conduction depressurization loop can complete the depressurization of the containment 2, the real-time air pressure in the containment 2 no longer rises to the second threshold air pressure, at this time, the radioactive gas in the containment can be discharged through the discharge pipeline 3, so that all the radioactive substances can be confined in the containment 2.

[0098] In some embodiments, in the case that the containment depressurization system comprises a waste liquid return pipeline. After the radioactive gas in the containment 2 is discharged into the cooling water in the heat exchange pool 1 through the discharge pipeline 3, the method further comprises: discharging the cooling water in the heat exchange pool 1 after absorbing the radioactive substances in the radioactive gas to the containment 2 through the liquid discharge pipeline 11.

[0099] After the radioactive gas in the containment 2 is discharged into the cooling water in the heat exchange pool 1 through the discharge pipeline 3, the cooling water absorbs the radioactive gas and becomes radioactive.

[0100] After the cooling water in the heat exchange pool 1 after absorbing the radioactive substances in the radioactive gas is discharged to the containment 2 through the liquid discharge pipeline 11, the radioactive substances can be contained in the containment 2 as much as possible.

[0101] After the containment vessel is depressurized by using the containment vessel depressurization method in the embodiment, it is analyzed that the level of radioactivity released into the environment is less than the general optimized intervention level specified in GB18871, that is, during the entire accident duration, the effective dose received by the public outside the radius of five kilometers centered on the containment vessel 2 is lower than the evacuation general optimized intervention level (50 mSv), the effective dose received by the public outside the radius of 10 kilometers is lower than the shelter general optimized intervention level (10 mSv), and the thyroid equivalent dose received by the public outside the radius of 10 kilometers is lower than the iodine protection general optimized intervention level (100 mGy), which can meet the basic standards of GB18871 Ionizing Radiation Protection and Radiation Source Safety.

[0102] Further, during the process of depressurizing the containment vessel 2 by using the method, after the radioactive gas is led out to the cooling water in the heat exchange pool 1 through the leading-out pipeline 3, the pressure of the atmosphere in the containment vessel 2 needs to be continuously monitored, and the leading-out pipeline 3 is closed when the pressure of the atmosphere in the containment vessel 2 drops to 0.31 MPa, at which time the containment vessel 2 is depressurized only by the circulation of the cooling water in the heat conduction depressurization loop, so as to as little as possible discharge the radioactive gas into the heat exchange pool 1.

[0103] It can be understood that the above embodiments are only exemplary embodiments for illustrating the principles of the present application, and the present application is not limited thereto. Various modifications and improvements can be made by those of ordinary skill in the art without departing from the spirit and essence of the present application, and these modifications and improvements are also considered to be within the protection scope of the present application.

Claims

1. A containment pressure relief system characterized by, The application relates to a radioactive gas discharge and pressure reduction system. The radioactive gas discharge and pressure reduction system comprises a heat exchange pool (1) arranged outside a safety shell (2) and storing cooling water, and a discharge pressure reduction circuit comprising a discharge pipeline (3) and a flow guide cover (4). The first end of the discharge pipeline (3) is communicated with the inside of the safety shell (2), the second end of the discharge pipeline (3) is inserted into the heat exchange pool (1) and is below the liquid level of the cooling water in the heat exchange pool (1), the radioactive gas in the safety shell (2) is discharged into the cooling water in the heat exchange pool (1) through the discharge pipeline (3), and the radioactive substance in the radioactive gas is removed by the cooling water. The flow guide cover (4) is arranged upside down above the second end of the discharge pipeline (3), the top of the flow guide cover (4) is above the liquid level of the cooling water in the heat exchange pool (1), the bottom of the flow guide cover (4) is below the liquid level of the cooling water in the heat exchange pool (1), and the gas after the radioactive substance is removed is received by the flow guide cover (4); the top of the flow guide cover (4) is provided with an exhaust hole, and the exhaust hole is used for discharging the gas in the flow guide cover (4) into the gas space in the heat exchange pool (1). The opening of the second end of the discharge pipeline (3) faces upwards.

2. The containment depressurization system of claim 1, wherein, The discharge pressure reduction circuit further comprises a sleeve (5) vertically arranged in the cooling water in the heat exchange pool (1), the lower end of the sleeve (5) is sleeved outside the second end of the discharge pipeline (3), and the upper end of the sleeve (5) is inserted into the flow guide cover (4) and is below the liquid level of the cooling water. A plurality of through holes are formed in the side wall of the top of the sleeve (5).

3. The containment depressurization system of claim 2, wherein, The discharge pipeline (3) comprises a main pipeline (6) and a plurality of branch pipelines (7); the main pipeline (6) is communicated with the inside of the safety shell (2), the plurality of branch pipelines (7) are horizontally immersed below the liquid level of the cooling water in the heat exchange pool (1) and are communicated with the main pipeline (6); a plurality of exhaust pipes (8) are arranged on each branch pipeline (7), and the pipe openings of the exhaust pipes (8) face upwards; the radioactive gas entering the main pipeline (6) is discharged into the cooling water in the heat exchange pool (1) through the plurality of exhaust pipes (8) on the branch pipelines (7).

4. The containment pressure relief system of claim 2, wherein, The number of the sleeves (5) is plural, the plurality of sleeves (5) are arranged in one-to-one correspondence with the plurality of exhaust pipes (8), and the lower end of each sleeve (5) is sleeved outside the pipe opening of the corresponding exhaust pipe (8). The number of the flow guide cover (4) is one, and the upper ends of all the sleeves (5) are inserted into the flow guide cover (4) and are below the liquid level of the cooling water. ​ 5. The containment pressure relief system of claim 2, wherein, The outlet pipe (3) includes a main pipe (6) and multiple branch pipes (7); the main pipe (6) is connected to the interior of the containment vessel (2), and the multiple branch pipes (7) are horizontally submerged below the cooling water surface in the hot water exchange tank (1) and are all connected to the main pipe (6); each branch pipe (7) is provided with multiple exhaust pipes (8), and the outlet of the exhaust pipe (8) faces upward; the radioactive gas entering the main pipe (6) is discharged into the cooling water in the hot water exchange tank (1) through the multiple exhaust pipes (8) on the branch pipes (7); The number of sleeves (5) is multiple, and the multiple sleeves (5) are arranged one-to-one with the multiple exhaust pipes (8). The lower end of each sleeve (5) is sleeved outside the opening of the corresponding exhaust pipe (8). The number of the flow guides (4) is multiple, and the multiple flow guides (4) are arranged one-to-one with the multiple branch pipes (7). The upper end of the sleeve (5) arranged corresponding to the multiple exhaust pipes (8) on one branch pipe (7) extends into the flow guide (4) corresponding to the branch pipe (7) and is below the cooling water surface.

6. The containment pressure relief system according to any one of claims 1-5, wherein, It also includes a heat-conducting voltage-reducing circuit; The heat conduction and pressure reduction circuit includes a heat exchange device (9), which is located inside the containment vessel (2) and connected to the heat exchange pool (1) via a circulation pipe (10) so that the cooling water in the heat exchange pool (1) can circulate between the heat exchange pool (1) and the heat exchange device (9), and the heat in the containment vessel (2) is transferred to the heat exchange pool (1) through the circulation of the cooling water.

7. The containment depressurization system of claim 6, wherein, It also includes waste liquid return pipelines; The waste liquid return pipeline includes a drain pipe (11), one end of which is connected to the bottom of the hot water exchange tank (1) and the other end is connected to the interior of the containment vessel (2), for discharging the cooling water in the hot water exchange tank (1) that has absorbed the radioactive substances in the radioactive gas into the containment vessel (2).

8. The containment pressure relief system of claim 7, wherein, It also includes control components; The control component includes: A barometer is installed inside the containment (2) to obtain the real-time air pressure inside the containment (2); The controller is electrically connected to the barometer and is used to acquire the real-time air pressure and control the first shut-off valve (12), the second shut-off valve (13), and the third shut-off valve (14) according to the real-time air pressure. The first shut-off valve (12) is installed on the outlet pipe (3) of the discharge pressure reduction circuit and is electrically connected to the controller, and is used to control the opening and closing of the outlet pipe (3) under the control of the controller. A second shut-off valve (13) is installed on the circulation pipe (10) of the heat conduction and pressure reduction circuit and is electrically connected to the controller, for controlling the opening and closing of the circulation pipe (10) under the control of the controller; and, The third shut-off valve (14) is installed on the drain pipe (11) of the waste liquid return pipeline and is electrically connected to the controller. It is used to control the opening and closing of the drain pipe (11) under the control of the controller.

9. A reactor building, characterized in that include: A containment vessel (2) internally provided with a loop system; and, The containment vessel depressurization system according to any one of claims 1-8.

10. A containment pressure reduction method, characterized by, The method using the containment vessel depressurization system according to any one of claims 1-8, the method comprising: monitoring a real-time air pressure in the containment vessel (2); comparing the real-time air pressure with a first threshold air pressure to obtain a first comparison result, and if the first comparison result is that the real-time air pressure is greater than the first threshold air pressure, then discharging radioactive gas inside the containment vessel (2) into cooling water in the heat exchange pool (1) through the discharge pipeline (3) to remove radioactive substances in the radioactive gas by the cooling water.

11. The containment pressure reduction method of claim 10, wherein, The containment vessel depressurization system is the containment vessel depressurization system according to any one of claims 6-8; After the monitoring of the real-time air pressure in the containment vessel (2), before the comparing of the real-time air pressure with the first threshold air pressure to obtain the first comparison result, the method further comprises: comparing the real-time air pressure with a second threshold air pressure to obtain a second comparison result, and if the second comparison result is that the real-time air pressure is greater than the second threshold air pressure, then enabling the cooling water in the heat exchange pool (1) to circulate between the heat exchange pool (1) and the heat exchange device (9) through the circulation pipeline (10), and discharging heat in the containment vessel (2) to the heat exchange pool (1) through the circulation of the cooling water; wherein the second threshold air pressure is less than the first threshold air pressure.

12. The containment pressure reduction method of claim 11, wherein, The containment vessel depressurization system is the containment vessel depressurization system according to claim 7 or 8; After the discharging of the radioactive gas inside the containment vessel (2) into the cooling water in the heat exchange pool (1) through the discharge pipeline (3), the method further comprises: discharging the cooling water in the heat exchange pool (1) after absorbing the radioactive substances in the radioactive gas into the containment vessel (2) through the liquid discharge pipeline (11).

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