Nuclear power plant equipment cooling water system

Abstract

This utility model discloses a cooling water system for nuclear power plant equipment, comprising a swaying water tank, a buffer container, a first pipe, and a first liquid level measuring device. The first liquid level measuring device is used to measure the liquid level in the swaying water tank. The height of the swaying water tank along the vertical direction is less than its width along the horizontal direction. The buffer container is at least partially located above the swaying water tank. The opposite ends of the first pipe are connected to the swaying water tank and the buffer container, respectively, and the buffer container and the swaying water tank are connected through the first pipe. Because a buffer container is installed above the swaying water tank and the buffer container and the swaying water tank are connected through the first pipe, it can be ensured that the swaying water tank is always full of water. Excess water is stored through the buffer container. The liquid level change caused by tilting and swaying in a full swaying water tank is very small, thereby reducing the impact of tilting and swaying in the marine environment on the liquid level measurement results.

Description

Technical Field

[0001] This utility model relates to the field of nuclear power technology, and in particular to a cooling water system for nuclear power plant equipment. Background Technology

[0002] The equipment cooling water system of a nuclear power plant provides cooling for users of the nuclear island system (including nuclear auxiliary systems and dedicated safety systems) under various normal operating conditions and performs certain safety functions under accident conditions. The tumbler tank in the equipment cooling water system is used to ensure the net positive suction head of the equipment cooling water pumps and to withstand volume changes in the equipment cooling water system due to temperature variations and leaks. In other words, the tumbler tank plays a safety role; to ensure the availability of the equipment cooling water system and the net positive suction head of the equipment cooling water pumps, the tumbler tank needs to be maintained at a safe liquid level. Therefore, the liquid level measurement of the tumbler tank is particularly important. Traditional technology uses a level gauge inserted into the tumbler tank for level measurement. However, in marine nuclear power systems, the tumbler tank is easily affected by the ship's rolling motion, resulting in tilting and swaying, making it impossible for the level gauge to accurately measure the liquid level. This phenomenon is particularly pronounced for "short and wide" tumbler tanks, and can even lead to one side of the tumbler tank being empty, causing the level gauge to fail and falsely triggering protection signals. This could then lead to the erroneous isolation of the equipment cooling water system, resulting in reactor shutdown and other problems. Utility Model Content

[0003] The technical problem to be solved by this utility model is to provide an improved cooling water system for nuclear power plant equipment, addressing at least one deficiency mentioned in the background art.

[0004] The technical solution adopted by this utility model to solve its technical problem is: to provide a cooling water system for nuclear power plant equipment, which includes a fluctuating water tank, a buffer container, a first pipeline and a first liquid level measuring element;

[0005] The first liquid level measuring device is used to measure the liquid level in the fluctuating water tank;

[0006] The height of the wave-shaped water tank along the vertical direction is less than the width of the wave-shaped water tank along the horizontal direction.

[0007] The buffer container is located at least partially above the undulating water tank, and the opposite ends of the first pipe are respectively connected to the undulating water tank and the buffer container, and the buffer container and the undulating water tank are connected through the first pipe.

[0008] In some embodiments, the bottom surface of the buffer container is higher than the top surface of the wave tank.

[0009] In some embodiments, the height of the buffer container along the vertical direction is greater than the length of the buffer container along the horizontal direction.

[0010] In some embodiments, a second pipe is further included, one end of which is connected to the buffer container, and the other end of which is used for drainage.

[0011] In some embodiments, a third pipe is further included, one end of which is connected to the bottom of the fluctuating water tank, and the first liquid level measuring element is mounted on the third pipe.

[0012] In some embodiments, the first liquid level measuring element is a differential pressure liquid level gauge.

[0013] In some embodiments, a device cooling water pump is also included, with the other end of the third pipe connected to the device cooling water pump.

[0014] In some embodiments, a heat exchanger and a fourth pipe are also included, the heat exchanger and the device cooling water pump being connected via the fourth pipe.

[0015] In some embodiments, a second liquid level measuring element is further included, which is used to measure the liquid level in the buffer container.

[0016] In some embodiments, the second level measuring element is a non-safety level gauge, and the first level measuring element is a safety level gauge.

[0017] This invention has at least the following beneficial effects: Since a buffer container is set above the wave tank and the buffer container and the wave tank are connected through a first pipe, it can be ensured that the wave tank is always full of water. Excess water is stored in the buffer container. The liquid level change caused by tilting and swaying of the full wave tank is very small, thereby reducing the impact of tilting and swaying in the marine environment on the liquid level measurement results and greatly reducing the risk of liquid level gauge failure caused by empty water on one side of the wave tank. Attached Figure Description

[0018] To more clearly illustrate the technical solution of this utility model, the following will further describe this utility model in conjunction with the accompanying drawings and embodiments. In the drawings:

[0019] Figure 1 This is a schematic diagram of the structure of a nuclear power plant equipment cooling water system in some embodiments of this utility model. Detailed Implementation

[0020] 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, 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; a mechanical connection or an electrical connection; a direct connection or an indirect connection through an intermediate medium; or a connection within two elements or an interaction between two elements. When an element is referred to as being "on" or "below" another element, the element can be located "directly" or "indirectly" on the other element, or there may be one or more intermediary elements. The terms "first," "second," and "third," etc., are used 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. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0021] Please see Figure 1 This utility model discloses a cooling water system for nuclear power plant equipment. This cooling water system is suitable for nuclear power systems in marine environments. Specific details regarding nuclear power systems in marine environments can be found in existing technology. The cooling water system includes a wave tank 1, a buffer container 2, a first pipe 31, and a first liquid level measuring element 41. The first liquid level measuring element 41 is used to measure the liquid level within the wave tank 1. The height H1 of the wave tank 1 along the vertical direction is less than the width W of the wave tank 1 along the horizontal direction. The vertical line refers to the line connecting the center of gravity of an object to the center of gravity of the Earth. The vertical direction can be referenced to direction AA in the figure, and the horizontal direction can be referenced to directions BB and CC in the figure. The width W of the wave tank 1 along the horizontal direction refers to its minimum horizontal dimension. For example, in… Figure 1In the illustrated embodiment, the wave tank 1 is a cuboid, with its dimension along the BB direction being smaller than its dimension along the CC direction. Therefore, the dimension of the wave tank 1 along the BB direction is also its width W along the horizontal direction. Of course, in other embodiments, the wave tank 1 may also be cylindrical or other shapes. Since the height H1 of the wave tank 1 along the vertical direction is smaller than its width W along the horizontal direction, the wave tank 1 is "short and stout" in operation. This "short and stout" shape poses a greater risk of tilting and swaying in nuclear power systems in marine environments, leading to liquid level measurement failure. To address this problem, the buffer container 2 is at least partially located above the wave tank 1. That is, the buffer container 2 can be entirely or partially located above the wave tank 1. In other words, the buffer container 2 is at least partially located on the side of the wave tank 1 furthest from the ground. The opposite ends of the first pipe 31 are connected to the wave tank 1 and the buffer container 2, respectively, and the buffer container 2 and the wave tank 1 are connected through the first pipe 31. In operation, the fluctuating water tank 1 is always full of water, and excess water flows to the buffer container 2 above.

[0022] In summary, because a buffer container 2 is installed above the undulating water tank 1 and connected to the undulating water tank 1 via a first pipe 31, it can be ensured that the undulating water tank 1 is always full of water. Excess water is stored in the buffer container 2. The liquid level change caused by tilting and swaying of the full-water undulating water tank 1 is very small (even negligible), thereby reducing the impact of tilting and swaying in the marine environment on the liquid level measurement results and greatly reducing the risk of liquid level gauge failure due to empty water on one side of the undulating water tank 1. Furthermore, this solution does not require modification of the inherent shape of the undulating water tank 1 ("short and stout"), and can be promoted and applied in existing engineering projects, demonstrating good economic efficiency and practicality.

[0023] like Figure 1 As shown, in some embodiments, the bottom surface 20 of the buffer container 2 is higher than the top surface 10 of the wave tank 1. That is, the buffer container 2 can be entirely located above the wave tank 1. When the water level in the wave tank 1 drops, under the action of gravity, the water in the higher-positioned buffer container 2 naturally flows into the wave tank 1 as a supplementary flow, which can ensure that the wave tank 1 remains full of water for a long time.

[0024] like Figure 1 As shown, in some embodiments, the nuclear power plant equipment cooling water system further includes a second pipe 32, one end of which is connected to the buffer container 2, and the other end of which is used for drainage. Specifically, the second pipe 32 can be used to drain excess water exceeding the maximum volume of the buffer container 2.

[0025] like Figure 1As shown, in some embodiments, the nuclear power plant equipment cooling water system further includes a third pipe 33, a fourth pipe 34, an equipment cooling water pump 5, and a heat exchanger 6. One end of the third pipe 33 is connected to the bottom of the undulating water tank 1. The bottom of the undulating water tank 1 is also the side of the undulating water tank 1 facing away from the buffer container 2. The other end of the third pipe 33 is connected to the equipment cooling water pump 5. The equipment cooling water pump 5 provides power for the water circulation of the nuclear power plant equipment cooling water system. The heat exchanger 6 and the equipment cooling water pump 5 are connected via a fifth pipe 35. Typically, the equipment cooling water system includes two equipment cooling water loops, each of which includes a undulating water tank 1, an equipment cooling water pump 5, and a heat exchanger 6. Figure 1 The diagram illustrates one of the equipment cooling water loops. The inlet of equipment cooling water pump 5 is connected to nuclear power unit 7 via a sixth pipe 36, receiving high-temperature water generated by heat exchange at nuclear power unit 7. The outlet of equipment cooling water pump 5 is connected to heat exchanger 6 via a fourth pipe 34. The medium passing through heat exchanger 6 ultimately exchanges heat with the ocean, transferring and dissipating the heat into the ocean. Heat exchanger 6 is connected to nuclear power unit 7 via a fifth pipe 35, supplying cooling water to nuclear power unit 7. After heat exchange at nuclear power unit 7, the cooling water regenerates into high-temperature water, which then enters equipment cooling water pump 5 via the sixth pipe 36, completing one heat exchange cycle to remove heat generated by heat exchangers and other components of nuclear power unit 7, as well as residual heat from the reactor core. Two equipment cooling water loops are connected to the same nuclear power unit 7, and the two equipment cooling water loops serve as backups for each other.

[0026] In the event of a leak in heat exchanger 6, excess water flows to the fluctuating water tank 1 and the buffer container 2, and is discharged through the second pipe 32, thereby preventing overpressure in the equipment cooling water system.

[0027] The first liquid level measuring element 41 is installed on the third pipe 33. Exemplarily, the first liquid level measuring element 41 can be a differential pressure level gauge or other existing liquid level measuring instruments. Unlike conventional technologies that insert the level gauge into the fluctuating water tank 1 for measurement, this solution places the first liquid level measuring element 41 on the third pipe 33 at the bottom of the fluctuating water tank 1, i.e., on the downstream pipeline of the fluctuating water tank 1. This allows for both measuring the liquid level in the fluctuating water tank 1 and indicating whether the downstream pipeline (i.e., the third pipe 33) is empty. When the downstream pipeline of the fluctuating water tank 1 is empty, the downstream equipment cooling water pump 5 is promptly shut down, and another backup equipment cooling water pump 5 is activated. This provides more sensitive and direct protection for the equipment cooling water pump 5. Alternatively, in other embodiments, the first liquid level measuring element 41 can also be installed on the fluctuating water tank 1. For example, the first liquid level measuring element 41 can also be an insertion-type liquid level transmitter. The sensor portion of the insertion-type liquid level transmitter can be directly inserted into the interior of the fluctuating water tank 1. Since the fluctuating water tank 1 can remain full of water for a long time, even if an insertion-type level transmitter is used to measure the liquid level in the fluctuating water tank 1, the phenomenon of the fluctuating water tank 1 tilting and swaying will not have a significant impact on the measurement results.

[0028] In some embodiments, a first threshold and a second threshold can be set for the liquid level of the fluctuating water tank 1. When the first liquid level measuring device 41 detects that the liquid level of the fluctuating water tank 1 is lower than or equal to the first threshold, an alarm signal is issued to remind the staff to check for leaks. When the first liquid level measuring device 41 detects that the liquid level of the fluctuating water tank 1 is lower than or equal to the second threshold, it indicates that all the water in the fluctuating water tank 1 has been lost, and the corresponding equipment cooling water pump 5 needs to be stopped immediately and another standby equipment cooling water pump 5 needs to be started.

[0029] like Figure 1 As shown, in some embodiments, the cooling water system of the nuclear power plant equipment further includes a second liquid level measuring element 42, which is used to measure the liquid level in the buffer container 2. Specifically, as... Figure 1 In the illustrated embodiment, the second level measuring element 42 is disposed on the buffer container 2. The second level measuring element 42 can be an insertion-type level transmitter, the sensor portion of which can be directly inserted into the interior of the buffer container 2. Alternatively, in other embodiments, the second level measuring element 42 can also be installed on the first pipe 31, which is the downstream pipeline of the buffer container 2. The second level measuring element 42 can also be a differential pressure level gauge.

[0030] In some embodiments, a third threshold can be set for the liquid level of the buffer container 2. When the second liquid level measuring element 42 detects that the liquid level of the buffer container 2 is lower than or equal to the third threshold, an alarm signal is issued to remind the staff to manually add water to the buffer container 2.

[0031] Since the fluctuating water tank 1 is directly connected to the cooling water pump, the liquid level information of the fluctuating water tank 1 is more important than that of the buffer container 2. Therefore, in some embodiments, the second liquid level measuring element 42 is a non-safety grade liquid level gauge, and the first liquid level measuring element 41 is a safety grade liquid level gauge. The safety grade liquid level gauge must meet international standards (such as IEC 61226) and nuclear safety regulations (such as HAF102) to ensure reliable operation under design-baseline accidents (such as LOCA loss-of-coolant accidents, earthquakes, and high radiation). The non-safety grade liquid level gauge only needs to meet general industrial standards (such as SH / T 3005), and does not need to consider reliability under accident conditions, resulting in lower cost.

[0032] like Figure 1 As shown, in some embodiments, the height H2 of the buffer container 2 along the vertical direction is greater than the length L of the buffer container 2 along the horizontal direction. The vertical direction can be referenced to direction AA in the figure, and the horizontal direction can be referenced to directions BB and CC in the figure. The length L of the buffer container 2 along the horizontal direction refers to its maximum dimension along the horizontal direction. For example, in... Figure 1 In the illustrated embodiment, the buffer container 2 is a cuboid, with its dimension along the BB direction being smaller than its dimension along the CC direction. Therefore, the dimension of the buffer container 2 along the CC direction is also its length L along the horizontal direction. Of course, in other embodiments, the buffer container 2 may also be cylindrical or other shapes. Since the height H2 of the buffer container 2 along the vertical direction is greater than its length L along the horizontal direction, it means that the buffer container 2 is "elongated" in its working state. The "elongated" type of buffer container 2 experiences less liquid level change due to tilting or swaying in a nuclear power system in a marine environment, thus reducing the risk of liquid level measurement failure.

[0033] It is understood that the above embodiments only illustrate preferred embodiments of the present utility model, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present utility model patent. It should be noted that for those skilled in the art, the above technical features can be freely combined, and several modifications and improvements can be made without departing from the concept of the present utility model, all of which fall within the protection scope of the present utility model. Therefore, all equivalent transformations and modifications made within the scope of the claims of the present utility model should fall within the coverage of the claims of the present utility model.

Claims

1. A nuclear power plant equipment cooling water system characterized by, It includes a wave tank (1), a buffer container (2), a first pipe (31), and a first liquid level measuring device (41); The first liquid level measuring device (41) is used to measure the liquid level in the fluctuating water tank (1); The height (H1) of the wave tank (1) along the vertical direction is less than the width (W) of the wave tank (1) along the horizontal direction; The buffer container (2) is at least partially located above the wave tank (1), and the opposite ends of the first pipe (31) are respectively connected to the wave tank (1) and the buffer container (2), and the buffer container (2) and the wave tank (1) are connected through the first pipe (31).

2. The nuclear power plant equipment cooling water system in accordance with claim 1, wherein, The bottom surface (20) of the buffer container (2) is higher than the top surface (10) of the wave tank (1).

3. The nuclear power plant equipment cooling water system in accordance with claim 1, wherein, The height (H2) of the buffer container (2) along the vertical direction is greater than the length (L) of the buffer container (2) along the horizontal direction.

4. The nuclear power plant equipment cooling water system in accordance with claim 1, wherein, It also includes a second pipe (32), one end of which is connected to the buffer container (2), and the other end of which is used for drainage.

5. The nuclear power plant equipment cooling water system in accordance with claim 1, wherein, It also includes a third pipe (33), one end of which is connected to the bottom of the fluctuating water tank (1), and the first liquid level measuring element (41) is installed on the third pipe (33).

6. The nuclear power plant equipment cooling water system in accordance with claim 5, wherein, The first liquid level measuring device (41) is a differential pressure liquid level gauge.

7. The nuclear power plant equipment cooling water system in accordance with claim 5, wherein, It also includes a device cooling water pump (5), and the other end of the third pipe (33) is connected to the device cooling water pump (5).

8. The nuclear power plant equipment cooling water system of claim 7, wherein, It also includes a heat exchanger (6) and a fourth pipe (34), the heat exchanger (6) and the equipment cooling water pump (5) being connected through the fourth pipe (34).

9. The nuclear power plant equipment cooling water system in accordance with claim 1, wherein, It also includes a second liquid level measuring device (42) for measuring the liquid level in the buffer container (2).

10. The nuclear power plant equipment cooling water system of claim 9, wherein, The second liquid level measuring device (42) is a non-safety grade liquid level gauge, while the first liquid level measuring device (41) is a safety grade liquid level gauge.

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