Reactor shutdown system and reactor pressure vessel pressure stabilizing system

Abstract

The utility model discloses a reactor shutdown system and a reactor pressure vessel pressure stabilizing system. The reactor shutdown system comprises a reactor pressure vessel, a storage tank, a high-pressure gas cylinder group and a pipeline, a cadmium nitrate solution is stored in the storage tank; high-pressure nitrogen is stored in the high-pressure gas cylinder group; the high-pressure gas cylinder group, the storage tank and the reactor pressure vessel are sequentially communicated through a pipeline; according to the utility model, the cadmium nitrate solution in the storage tank is pushed into the reactor pressure vessel by using the high-pressure nitrogen in the high-pressure gas cylinder group, so as to realize shutdown of the reactor pressure vessel; a passive injection mode is adopted, so that the reliability of the system is improved, a reactor shutdown system can still be executed under the condition that a power supply is completely lost, the diversified requirements of the reactor shutdown system means are met, and the reliability of the system is improved; a novel injection material is used, existing pipelines in the system are utilized, a large number of devices are reduced, and the requirement for spatial arrangement is reduced.

Description

Technical Field

[0001] This utility model relates to the field of nuclear power, and in particular to a reactor shutdown system and a reactor pressure vessel pressure stabilization system. Background Technology

[0002] Conventional pressurized water reactor nuclear power plants typically require two reactor shutdown systems. These two systems must be independent of each other and differ as much as possible in their methods or principles to reduce the probability of common-cause failures. The most common method for the first reactor shutdown system is lowering or raising control rods, while the second reactor shutdown system mostly still uses the movement of control rods as a secondary shutdown method. If both reactor shutdown systems are identical in method or principle, it does not ideally meet the requirement of diversity.

[0003] Alternatively, the secondary reactor shutdown system could employ active boric acid injection as a secondary shutdown method. Traditional active boric acid injection relies on active equipment, rendering this secondary shutdown method ineffective in the event of a power outage. Active boric acid injection also requires additional pump sets to perform the injection function, and the active equipment occupies a significant amount of space, making it unsuitable for projects with high space requirements. The substance injected in the secondary shutdown method is always boric acid. Furthermore, due to the physical properties of concentrated boric acid, it is highly prone to crystallization, thus requiring heating or stirring equipment to ensure the stability of the concentrated boric acid solution. Heating or stirring equipment further increases the space requirements of this system. Utility Model Content

[0004] The technical problem to be solved by this invention is to provide a reactor shutdown system.

[0005] The technical solution adopted by this utility model to solve its technical problem is:

[0006] A reactor shutdown system, comprising:

[0007] Reactor pressure vessel;

[0008] The storage tank contains a cadmium nitrate solution.

[0009] High-pressure gas cylinder assembly, which stores high-pressure nitrogen gas; and

[0010] Pipelines are used to sequentially connect the high-pressure gas cylinder group, the storage tank, and the reactor pressure vessel, and the high-pressure nitrogen gas from the high-pressure gas cylinder group is used to transport the cadmium nitrate solution in the storage tank to the reactor pressure vessel.

[0011] Furthermore, in the aforementioned reactor shutdown system, preferably the altitude of the storage tank is higher than that of the reactor pressure vessel, the storage tank has an air inlet, the air inlet is connected to the high-pressure gas cylinder group through the pipeline, and the air inlet is higher than the highest liquid level of the cadmium nitrate solution in the storage tank.

[0012] Furthermore, in the aforementioned reactor shutdown system, a valve assembly is preferably installed on the pipeline connecting the storage tank to the reactor pressure vessel.

[0013] Furthermore, in the aforementioned reactor shutdown system, the valve assembly preferably includes at least one set of first valves and second valves connected in series.

[0014] Furthermore, in the aforementioned reactor shutdown system, a third valve is preferably installed on the pipeline between the storage tank and the valve assembly.

[0015] Furthermore, in the aforementioned reactor shutdown system, the first valve is preferably a check valve, the second valve is a shut-off valve, and the third valve is an isolation valve.

[0016] Furthermore, in the aforementioned reactor shutdown system, preferably multiple high-pressure gas cylinder groups are arranged in parallel, and the high-pressure gas cylinder groups are interconnected, with a fourth valve provided between the multiple high-pressure gas cylinder groups.

[0017] Furthermore, in the aforementioned reactor shutdown system, it is preferable that the high-pressure gas cylinder group is connected to a compressor.

[0018] A reactor pressure vessel pressurization system includes a pressurizer adapted to the reactor shutdown system, wherein the pressurizer stores primary coolant and nitrogen gas covering the primary coolant.

[0019] The reactor pressure vessel is connected to the pressurizer through a first flow pipe, which is inserted into the lowest point of the primary loop water level.

[0020] The high-pressure gas cylinder group is connected to the pressure regulator through a second flow tube, which is inserted into the pressure regulator at the highest point of the nitrogen gas level.

[0021] Furthermore, in the aforementioned reactor pressure vessel pressure stabilization system, preferably, multiple pressure stabilizers are provided.

[0022] The present invention has the following advantages: it uses high-pressure nitrogen gas from the high-pressure gas cylinder group to push cadmium nitrate solution from the storage tank into the reactor pressure vessel, thereby shutting down the reactor pressure vessel; it adopts a passive injection method, which improves the reliability of the system, and the reactor shutdown system can still be executed even in the event of a complete power loss, meeting the diverse requirements of reactor shutdown system methods and improving the reliability of the system; it uses a new injection material and utilizes existing pipelines in the system, reducing the addition of a large number of equipment and reducing the space requirements. Attached Figure Description

[0023] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings:

[0024] Figure 1 This is a schematic diagram of the structure of the reactor shutdown system and reactor pressure vessel stabilization system assembly in some embodiments of this utility model;

[0025] Figure 2 yes Figure 1 The diagram shows the structure of the reactor shutdown system.

[0026] Figure 3 yes Figure 1 The diagram shows the structure of the reactor shutdown system and the reactor pressure vessel pressurization system assembly. Detailed Implementation

[0027] To provide a clearer understanding of the technical features, objectives, and effects of this utility model, the specific embodiments of this utility model are now described in detail with reference to the accompanying drawings. In the following description, it should be understood that the orientations or positional relationships indicated by terms such as "front," "rear," "upper," "lower," "left," "right," "longitudinal," "horizontal," "vertical," "horizontal," "top," "bottom," "inner," "outer," "head," and "tail" are based on the orientations or positional relationships shown in the accompanying drawings, and are constructed and operated in a specific orientation. They are only for the convenience of describing this technical solution and do not indicate that the device or component referred to must have a specific orientation; therefore, they should not be construed as limitations on this utility model.

[0028] It should also be noted that, unless otherwise explicitly specified and limited, terms such as "installation," "connection," "joining," "fixing," and "setting" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. When an component is referred to as being "on" or "below" another component, the component can be located "directly" or "indirectly" on the other component, or there may be one or more intermediary components. The terms "first," "second," "third," etc., are only for the convenience of describing this technical solution and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, features defined with "first," "second," "third," etc., may explicitly or implicitly include one or more of that feature. For those skilled in the art, the specific meaning of the above terms in this utility model can be understood according to the specific circumstances.

[0029] In the following description, specific details such as particular system structures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of the present invention. However, those skilled in the art will understand that the present invention can be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods are omitted so as not to obscure the description of the present invention with unnecessary detail.

[0030] The technical solution adopted by this utility model to solve its technical problem is:

[0031] like Figure 1 and Figure 2As shown, some embodiments of this utility model disclose a reactor shutdown system. In some embodiments, this reactor shutdown system may include: a reactor pressure vessel 10, a storage tank 20, a high-pressure gas cylinder group 30, and pipelines 40. The storage tank 20 is connected to the reactor pressure vessel 10 via pipeline 40 and stores cadmium nitrate solution inside. The high-pressure gas cylinder group 30 is connected to the storage tank 20 via pipeline 40 and stores high-pressure nitrogen gas inside. The high-pressure nitrogen gas inside the high-pressure gas cylinder group 30 pushes the cadmium nitrate solution in the storage tank 20 to the reactor pressure vessel 10, thereby shutting down the reactor pressure vessel 10. On one hand, a passive injection method is used, utilizing high-pressure thrust injection, which allows for shutdown even in the event of a complete power outage. On the other hand, a novel injection material is used, eliminating the need for easily crystallizing solutions such as boric acid, reducing the need for heating or stirring equipment, and thus reducing space requirements. Furthermore, considering the overall design of a small reactor, the system fully utilizes the equipment and pipelines of other systems, achieving the reactor shutdown system function through valve opening and closing with minimal addition of equipment.

[0032] Continue to refer to Figure 1 In some embodiments, pipeline 40 may include a first pipeline, a second pipeline, and a third pipeline. One end of the first pipeline is connected to the reactor pressure vessel 10, one end of the second pipeline is connected to the other end of the first pipeline, and the other end of the second pipeline is connected to the storage tank 20. The first pipeline and the second pipeline are interconnected, and the reactor pressure vessel 10 is connected to the storage tank 20 through the first and second pipelines, so that the cadmium nitrate solution in the storage tank 20 can flow into the reactor pressure vessel 10. The two ends of the third pipeline are connected to the storage tank 20 and the high-pressure gas cylinder group 30, respectively. High-pressure nitrogen gas in the high-pressure gas cylinder group 20 enters the storage tank 20 through the third pipeline and enters the top of the storage tank 20 to force the cadmium nitrate solution at the bottom of the storage tank 20 into the reactor pressure vessel 10.

[0033] In some embodiments, the second conduit is also connected to other equipment in the reactor primary loop, so that the other equipment can be connected to the reactor pressure vessel 10. This increases the utilization of existing systems and conduits, reduces the need for new equipment, and saves money.

[0034] In some embodiments, the storage tank 20 is at an altitude higher than the reactor pressure vessel 10. The storage tank 20 is set at a higher altitude than the reactor pressure vessel 10 so that the cadmium nitrate solution in the storage tank 20 can flow into the reactor pressure vessel 10 from the higher altitude, making full use of its own gravity (height difference) to enter the reactor pressure vessel 10, reducing the use of high-pressure nitrogen and saving resources.

[0035] The pipeline 40 connecting the high-pressure gas cylinder assembly 30 to the storage tank 20 is positioned above the highest liquid level of the cadmium nitrate solution in the storage tank 20. In other words, the second pipeline is connected to the storage tank 20 above the highest liquid level of the cadmium nitrate solution in the storage tank 20. That is, the second pipeline is connected to the top or near the top of the storage tank 20, and the high-pressure nitrogen in the high-pressure gas cylinder assembly 30 fills the top of the storage tank 20 so that the high-pressure nitrogen covers the cadmium nitrate solution, using pressure to rapidly force the cadmium nitrate solution into the reactor pressure vessel 10.

[0036] In other words, the storage tank 20 has an air inlet, which is connected to the high-pressure gas cylinder group 30 via a pipeline 40. The air inlet is higher than the highest liquid level of the cadmium nitrate solution in the storage tank 20 so that high-pressure nitrogen gas covers the cadmium nitrate solution.

[0037] Continue to refer to Figure 1 The reactor shutdown system also includes a valve assembly 50 installed on the pipeline 40 connecting the storage tank 20 to the reactor pressure vessel 10 to control the flow between the storage tank 20 and the reactor pressure vessel 10. That is, the flow between the first pipeline and / or the second pipeline. The reactor shutdown system is opened and closed by controlling the valves, and non-kinetic energy injection is used, so shutdown injection can be achieved even in the event of power loss.

[0038] Valve assembly 50 includes at least one set of first valves 51 and second valves 52 installed in series on the first pipeline (pipeline 40). The first valves 51 and second valves 52 are respectively a check valve and a gate valve, used to ensure that fluid flows only in one direction and to stop flow when necessary. A check valve, also known as a non-return valve, is an automatically opening and closing valve used to prevent reverse flow of fluid. A gate valve, on the other hand, is a valve that can be completely closed to control the flow of fluid. This combination provides additional safety by preventing backflow and accidental leakage.

[0039] In other embodiments, the valve assembly 50 includes two sets of first valves 51 and second valves 52 connected in series. If one set of first valves 51 and second valves 52 fails, the other set can be used to increase the safety of the pipeline 40.

[0040] The reactor shutdown system also includes a third valve 60 installed on the second pipeline (pipeline 40). The third valve 60 is an isolation valve to control the flow between the storage tank 20 and the reactor pressure vessel 10. When a shutdown is required, the isolation valve is opened, allowing the cadmium nitrate solution in the storage tank 20 to flow into the reactor pressure vessel 10. When a shutdown is not required, the isolation valve is normally closed to prevent the cadmium nitrate solution in the storage tank 20 from flowing into the reactor pressure vessel 10.

[0041] Continue to refer to Figure 1In some embodiments, multiple high-pressure gas cylinder groups 30 are provided, which are interconnected. A fourth valve 32 is provided between the multiple high-pressure gas cylinder groups 30 to control the flow between them. When the pressure of the high-pressure gas cylinder group 30 supplying high-pressure nitrogen to the storage tank 20 is unstable, the other high-pressure gas cylinder groups 30 can inject their internal high-pressure nitrogen into the high-pressure gas cylinder group 30 supplying high-pressure nitrogen to the storage tank 20 to ensure the injection of cadmium nitrate solution. The fourth valve 32 controls the flow between the multiple high-pressure gas cylinder groups 30.

[0042] In some embodiments, the high-pressure gas cylinder group 30 is also connected to a compressor 90. When the pressure inside the high-pressure gas cylinder group 30 is insufficient, the compressor 90 can replenish the high-pressure gas cylinder group 30 with high-pressure nitrogen to ensure that the cadmium nitrate solution is injected from the storage tank 20 into the reactor pressure vessel 10. In some embodiments, the high-pressure gas cylinder group 30 may also be equipped with a first pressure gauge 31 for detecting the pressure inside the high-pressure gas cylinder group 30.

[0043] like Figure 1 and Figure 3 As shown, the reactor pressure vessel stabilization system in some embodiments includes a pressurizer 70, which is adapted to the reactor shutdown system to ensure the pressure stability of the primary loop of the reactor pressure vessel 10.

[0044] In some embodiments, the pressurizer 70 stores primary loop water and nitrogen gas covering the primary loop water. The reactor pressure vessel 10 is connected to the pressurizer 70 via a first flow pipe 80, which is inserted to the lowest point of the primary loop water level. The high-pressure gas cylinder group 30 is connected to the pressurizer 70 via a second flow pipe 81, which is connected to the inner top wall of the pressurizer 70 (the second flow pipe 81 is inserted to the highest point of the nitrogen gas level in the pressurizer 70). During use, the temperature of the reactor pressure vessel 10 changes. The water in the reactor pressure vessel 10 expands due to heat and enters the pressurizer 70 through the first flow pipe 80. As the amount of primary loop water inside the pressurizer 70 increases, the nitrogen gas inside is forced into the high-pressure gas cylinder group 30 to ensure the stability of the internal pressure of the reactor pressure vessel 10. Conversely, when the volume or amount of water in the reactor pressure vessel 10 decreases, the primary loop water in the pressurizer 70 will enter the reactor pressure vessel 10; when the nitrogen inside the pressurizer 70 decreases, the nitrogen in the high-pressure gas cylinder group 30 will enter the pressurizer 70.

[0045] In some embodiments, a fifth valve 82 may be installed on the second flow pipe 81. Specifically, the fifth valve 82 includes an isolation valve and a quick-closing valve (isolation valve), and the quick-closing valve needs to perform the function of quick closing.

[0046] Continue to refer to Figure 1In some embodiments, multiple pressurizers 70 can be installed. These multiple pressurizers 70 are connected to the reactor pressure vessel 10 via first flow pipes 80, and are further connected to multiple sets of high-pressure gas cylinder groups 30 via multiple second flow pipes 81. On the one hand, from the perspective of improving the safety and reliability of nuclear power, redundancy needs to be considered. In the event of an accident, damage, or the need for regular maintenance, the pressurizer 70 can be switched at any time, allowing the reactor pressure vessel 10 to continue operating safely and stably. On the other hand, from a space perspective, stability requires a fixed total water and gas capacity. Therefore, by using multiple pressurizers 70 instead of a single one, surrounding corner spaces can be utilized, significantly improving space utilization. Furthermore, from an accident mitigation perspective, the pressurizer 70 can act as an isolation device; if one part is lost, the remaining parts can still be used.

[0047] In some embodiments, the second flow tube 81 may also be equipped with a second pressure gauge 83 for measuring the pressure between the high-pressure gas cylinder group 30 and the pressure regulator 70. The pressure regulator 70 may be equipped with a level gauge 71 inserted into the primary circuit water for measuring the level of the primary circuit water inside the pressure regulator 70.

[0048] The reactor shutdown system will be further explained below in conjunction with its usage.

[0049] When the reactor shutdown system is in use: valve assembly 50 and third valve 60 are opened simultaneously, and high-pressure gas cylinder group 30 uses high-pressure nitrogen to push cadmium nitrate solution in storage tank 20 into reactor pressure vessel 10 to shut down reactor pressure vessel 10.

[0050] When the reactor shutdown system is not in use: the third valve 60 is closed, disconnecting the flow between the storage tank 20 and the reactor pressure vessel 10. Valve assembly 50 may remain open to allow flow between other systems and the reactor pressure vessel 10 via valve assembly 50.

[0051] It should be noted that, for those skilled in the art, without departing from the concept of this utility model, the above-mentioned technical features can be freely combined, and several modifications and improvements can be made, all of which fall within the protection scope of this utility model.

Claims

1. A reactor shutdown system, characterized in that, include: Reactor pressure vessel (10); Storage tank (20) contains cadmium nitrate solution; High-pressure gas cylinder assembly (30), which stores high-pressure nitrogen gas; and The pipeline (40) connects the high-pressure gas cylinder group (30), the storage tank (20) and the reactor pressure vessel (10) in sequence, and the cadmium nitrate solution in the storage tank (20) is transported to the reactor pressure vessel (10) through the high-pressure nitrogen gas in the high-pressure gas cylinder group (30).

2. The reactor shutdown system according to claim 1, characterized in that, The altitude of the storage tank (20) is higher than that of the reactor pressure vessel (10). The storage tank (20) has an air inlet, which is connected to the high-pressure gas cylinder group (30) through the pipeline (40). The air inlet is higher than the highest liquid level of the cadmium nitrate solution in the storage tank (20).

3. The reactor shutdown system according to claim 2, characterized in that, A valve assembly (50) is provided on the pipeline (40) connecting the storage tank (20) to the reactor pressure vessel (10).

4. The reactor shutdown system according to claim 3, characterized in that, The valve assembly (50) includes at least one set of first valves (51) and second valves (52) connected in series.

5. The reactor shutdown system according to claim 4, characterized in that, A third valve (60) is provided on the pipeline (40) between the storage tank (20) and the valve assembly (50).

6. The reactor shutdown system according to claim 5, characterized in that, The first valve (51) is a check valve, the second valve (52) is a shut-off valve, and the third valve (60) is an isolation valve.

7. The reactor shutdown system according to claim 1, characterized in that, Multiple high-pressure gas cylinder groups (30) are arranged in parallel, and the high-pressure gas cylinder groups (30) are connected to each other. A fourth valve (32) is provided between the multiple high-pressure gas cylinder groups (30).

8. The reactor shutdown system according to claim 1, characterized in that, The high-pressure gas cylinder group (30) is connected to a compressor (90).

9. A reactor pressure vessel pressure stabilization system, characterized in that, Includes a pressurizer (70), the pressurizer (70) being adapted to the reactor shutdown system according to any one of claims 1 to 8, the pressurizer (70) storing primary loop water and storing nitrogen gas covering the primary loop water; The reactor pressure vessel (10) is connected to the pressurizer (70) through a first flow pipe (80), and the first flow pipe (80) is inserted into the lowest point of the primary loop water level; The high-pressure gas cylinder group (30) is connected to the pressure regulator (70) through a second flow tube (81), and the second flow tube (81) is inserted into the pressure regulator (70) at the highest point of the nitrogen gas level.

10. The reactor pressure vessel stabilization system according to claim 9, characterized in that, The voltage regulator (70) is provided in multiple forms.

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