Nuclear reactor steam generator secondary side water supply ring pipe foreign matter real flow visual motion experiment system and method

Abstract

The invention discloses a nuclear reactor steam generator secondary side water supply ring pipe foreign matter real flow visual motion experiment system and method. The system comprises a main loop adjusting and monitoring module, an experiment section module and an image acquisition module, and the main loop adjusting and monitoring module is composed of a water storage tank, a water supply pump, a flow conveying pipeline, a loop valve and a foreign matter collection filter; the experiment section module is composed of a modeling steam generator water supply ring pipe experiment section. The image acquisition module is realized through high-speed camera shooting and experimental data storage. According to the system, modular design is adopted, experimental loop transportation work is completed under the conditions that experimental equipment is protected as much as possible and experimental loops are disassembled as little as possible, and the invention further provides an experimental method of the system. According to the invention, the requirement of visual experiment research on the motion law of the foreign matters on the secondary side of the nuclear reactor steam generator under the condition of large flow can be met, and meanwhile, system parameters can be simply, conveniently and quickly adjusted.

Description

Technical Field

[0001] This invention belongs to the technical field of nuclear power equipment performance verification experimental research, specifically relating to a real-flow visualization experimental system and method for foreign object movement in the secondary side feedwater ring pipe of a nuclear reactor steam generator. Background Technology

[0002] The steam generator in a nuclear power system is a key piece of equipment connecting the primary and secondary loops of a nuclear power plant. It also serves as a heat exchange boundary, a pressure boundary, and a radiation protection barrier. Therefore, ensuring the integrity of the steam generator and its internal structure is of paramount importance.

[0003] During the operation of a nuclear power system, foreign matter can enter the secondary loop water and participate in the circulation due to reasons such as the detachment of secondary loop equipment components and external intrusion during maintenance. This foreign matter remains in the secondary side of the steam generator for extended periods, and the fluid impact during system operation can cause wear and tear on structures such as heat transfer tubes, increasing the risk of heat transfer tube breakage and threatening the safe operation of the nuclear power system. While existing maintenance methods can remove some foreign matter by grabbing, some foreign matter buried in sludge or stuck in components remains difficult to detect and remove. Existing maintenance methods are insufficient to meet the needs of nuclear power plant maintenance and repair.

[0004] Since the nuclear power plant began operation, there have been multiple cases of wear on the secondary side heat transfer tubes of the steam generator caused by foreign objects. These foreign objects pose significant hidden dangers to the safe operation of the nuclear power system and also cause substantial economic losses to the nuclear power plant.

[0005] To investigate the motion trajectory and migration distribution of different foreign objects on the secondary side of the steam generator, as well as the force behavior between the foreign objects and the feedwater ring pipe, it is necessary to conduct a live fluid experiment on the foreign objects on the secondary side of the steam generator.

[0006] For example, Chinese patent application publication number CN105938074B discloses a hydraulic flushing experimental system and method for the lower tube seat of a nuclear reactor fuel assembly. This system can meet the needs of visual experimental research on the hydraulic flushing performance of the reactor lower tube seat under high flow rates. However, the experimental setup focuses on the lower tube seat filter structure, not the secondary feedwater ring structure of the steam generator, as their structural characteristics differ. Secondly, this experimental setup focuses on and measures pressure drop characteristics, filtration efficiency, resistance to scour damage, and the impact of foreign object blockage on the downstream flow field. In contrast, the performance indicators of the secondary feedwater ring pipe of a steam generator are the movement and distribution patterns of foreign objects. Therefore, this detection method, device, and system are not suitable for testing the movement and distribution of foreign objects in the secondary feedwater ring pipe of a steam generator. Summary of the Invention

[0007] To address the limitations of the aforementioned experimental setup in meeting the needs of nuclear engineering for experimental research on the motion patterns of foreign matter on the secondary side of a steam generator, the present invention aims to provide a visualization experimental system and method for the motion of foreign matter in the secondary feedwater ring of a nuclear reactor steam generator. This system enables the visualization of the motion patterns of foreign matter in the experimental section, while also allowing for convenient and rapid adjustment of system parameters. It can obtain experimental parameters such as pressure and flow rate, and utilize high-speed imaging technology to capture the motion state and trajectory of the foreign matter, facilitating in-depth research on the motion patterns of foreign matter in the steam generator.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: A real-time visualization motion experimental system for foreign matter in the secondary feedwater loop of a nuclear reactor steam generator includes a double-suction pump 1 and a bypass valve 2 connected in parallel with the double-suction pump in the main circulation loop, a first Y-type filter 8 on the upstream pipe of the double-suction pump 1, a water tank 7 on the upstream pipe of the first Y-type filter 8, a pressure gauge 6 installed on the inlet pipe of the water tank 1, a water injection valve 71 at the bottom of the water tank, and a level gauge 72 on one side of the water tank 7. The functions of the above components in the loop are to provide circulation power, regulate flow, filter the inlet fluid of the pump, stabilize the pressure of the liquid storage, monitor the pressure of the main circulation loop, replenish the water tank level, and monitor the water tank level, respectively. The above components constitute the main loop regulation and monitoring module of the system. A main valve 3 is connected to the downstream pipeline of the double-suction pump 1, which controls the opening and closing of the flow transmission in the entire loop. A flow meter 31 is installed downstream of the main valve 3 to monitor the flow in the corresponding experimental section. A second Y-type filter 32 is installed downstream of the flow meter 31 to filter the fluid entering the experimental section and prevent the backflow and loss of foreign objects during the experiment. Downstream of the second Y-type filter 32, there is a foreign object inlet consisting of a lower foreign object inlet valve 322 and an upper foreign object inlet valve 321, an experimental section inlet hose 341, a visual water supply loop experimental section 33, and an experimental section outlet hose 341. 42, wherein the foreign object inlet is equipped with a lower foreign object inlet valve 322 and an upper foreign object inlet valve 321 in the vertical direction to prevent leakage of the circuit water when the valve is opened to put in foreign objects; the experimental section drain valve 332, the experimental section exhaust valve 331 and the experimental section outlet valve 34 installed on the experimental section outlet hose 342 are installed on the experimental section drainage pipe experimental section 33. The above system pipes and connectors together form the experimental section module. The experimental section 33 of the visual feedwater loop pipe is used to simulate the secondary side feedwater loop pipe of the nuclear reactor steam generator. Downstream of the third flow regulating valve 34, there is a foreign matter collection tank 4 and a third Y-type filter 5, which are used to collect foreign matter leaving the experimental section during the circulation. The system's image acquisition module consists of a high-speed camera 9, a local area network computer 10, and a storage device 11 connected together. The high-speed camera 9 records the process of foreign objects entering and leaving the water supply ring pipe in the experimental section. The local area network computer 10 is connected to the high-speed camera 9 and can provide timely feedback on the shooting results of the high-speed camera 9 and save the shooting results in the storage device 11, which facilitates the recording and archiving of experimental results and the post-processing of experimental data.

[0009] Preferably, the test section 33 of the visualized water supply ring pipe is made of plexiglass, including an air vent valve 331, a drain valve 332, a top cover 333, a cylinder 334, a base 335, a descending section 336, a central pipe 337, and a water supply ring assembly composed of a water supply ring pipe 338 and an inverted J-shaped pipe 339. The top cover 333 is located at the top of the cylinder 334, serving to seal the test section, and has an air vent valve 331 at its top. The base 335 is located at the bottom of the cylinder 333 and has a drain valve 332. The central pipe 337 is located at the center of the cylinder 334, and together with the cylinder 334, separates the descending section 336, allowing water to flow through the ring. The water ring pipe 338 surrounds the central pipe, and the upper part is equipped with inverted J-shaped pipes 339. The inlet and outlet of the visual water supply ring pipe test section require additional flange structures to connect with the main circulation loop pipe. Foreign objects enter from the inlet of the water supply ring pipe 338, pass through the inverted J-shaped pipe 339 and enter the descending section 336. Larger foreign objects sink to the bottom of the cylinder, while smaller foreign objects leave the test section through the central pipe 337. In actual installation, in order to ensure the stability of the test section, the structure in the visual water supply ring pipe test section is fixed with acrylic glue. Considering the disassembly and installation requirements, the top cover and base are designed as plate structures.

[0010] The high-speed camera 9 can be easily moved to clearly record the process of foreign objects entering and leaving the water supply ring pipe in the experimental section.

[0011] Before the experiment, the main circulation loop was filled with water for leak detection and anti-destruction test to ensure that the main circulation loop had no leakage under high flow and that the test section was intact and undamaged. When the main circulation loop is started, keep the main valve 3, the test section outlet valve 34, and the test section exhaust valve 331 in the open state, and keep the bypass valve 2, the test section drain valve 332, the upper foreign object inlet valve 321, and the lower foreign object inlet valve 322 in the closed state. Start the double suction pump 1, and close the test section exhaust valve 331 when the test section is filled with water. When adjusting the circulation flow of the main circulation loop, turn on the double suction pump 1 and adjust the frequency of the double suction pump inverter according to the reading of the flow meter 31 until the design flow is reached. When adjusting the flow rate of the bypass circuit, open bypass valve 2 and adjust its opening degree; When conducting the experiment on the movement of foreign objects in the secondary feedwater loop of a nuclear reactor steam generator, after opening the main circulation loop, closing the bypass loop, and adjusting the fluid flow rate to the required level as described above, and once the main circulation loop is running stably, the experimental foreign object element is introduced. Simultaneously, the high-speed camera 9 is turned on to record the experimental process. When introducing the experimental foreign object element, the lower foreign object inlet valve 322 is closed, and the upper foreign object inlet valve 321 is opened. The foreign object is then introduced into the upper foreign object inlet, allowing it to fall into the inlet pipe. The upper foreign object inlet valve 321 is then closed, and the lower foreign object inlet valve 322 is opened, allowing the foreign object to fall into the circulating water loop pipe and enter the experimental section along with the circulating water. Simultaneously, the high-speed camera 9 is turned on, and the movement of the foreign object in the feedwater loop is observed and recorded using the local area network computer 10. After the experiment, the double-suction pump 1 is turned off, the captured results are archived in the storage device 11, and the foreign objects are collected, organized, and documented in writing. The recovered foreign objects include those at the bottom of the experimental section sleeve and those in the experimental section outlet foreign object collection tank.

[0012] Compared with the prior art, the present invention has the following advantages: 1. The experimental system and method described in this invention realizes the actual flow visualization motion experiment of foreign objects in the secondary side feedwater ring pipe of a nuclear reactor steam generator. By placing foreign objects into the experimental system, the motion trajectory experiment of foreign objects in the feedwater ring pipe can be carried out, realizing a comprehensive study on the motion distribution law of foreign objects on the secondary side of the steam generator. 2. The experimental system features a modular design, facilitating disassembly and transportation, as well as the placement and replacement of experimental components and the recovery of foreign objects; 3. The experimental section is made of plexiglass, which, while meeting the strength requirements of the experiment, has high transparency, thus enabling the visualization of the experimental process. 4. The experimental section is the water supply loop area, made of transparent material, which is easy to disassemble and facilitates recording the movement trajectory of foreign objects and recovering them; 5. High-speed photography technology is used to record the experimental process in real time. The complete image data is beneficial for comparing and observing the results under different experimental conditions after the experiment, and for further in-depth research on the experimental phenomena and processes. Attached Figure Description

[0013] Figure 1 This is a system diagram of the experimental system of the present invention.

[0014] Figure 2a To visualize the front sectional view of the test section of the water supply loop pipe, Figure 2b This is a top view of the water supply loop pipe. Figure 2c A cross-sectional view of the inverted J-shaped pipe at the top of the water supply ring pipe and a diagram showing the fit between the inverted J-shaped pipe and the water supply ring pipe. Detailed Implementation

[0015] The present invention will now be described in detail with reference to the accompanying drawings and embodiments: like Figure 1 As shown, this invention relates to a visualization experimental system and method for the actual flow of foreign matter in the secondary feedwater loop of a nuclear reactor steam generator. The system includes a double-suction pump 1 and a bypass valve 2 connected in parallel with the double-suction pump in the main circulation loop; a first Y-type filter 8 on the upstream pipe of the double-suction pump 1; a water tank 7 on the upstream pipe of the first Y-type filter 8; a pressure gauge 6 installed on the inlet pipe of the water tank 1; a water injection valve 71 at the bottom of the water tank; and a level gauge 72 on one side of the water tank 7. The functions of these components in the loop are respectively to provide circulation power, regulate flow rate, filter the inlet fluid of the pump, stabilize the pressure of the stored liquid, monitor the pressure of the main circulation loop, and replenish the fluid. The water tank level and its monitoring constitute the main loop regulation and monitoring module of the system. A main valve 3 is connected to the downstream pipe of the double-suction pump 1, controlling the flow rate of the entire loop. A flow meter 31 is installed downstream of the main valve 3 to monitor the flow rate of the corresponding experimental section. A second Y-type filter 32 is installed downstream of the flow meter 31 to filter the fluid entering the experimental section and prevent backflow and loss of foreign objects during the experiment. Downstream of the second Y-type filter 32 is a foreign object inlet consisting of a lower foreign object inlet valve 322 and an upper foreign object inlet valve 321, and an experimental section inlet hose 341. The experimental section consists of a visual feedwater loop test section 33 and an experimental section outlet hose 342. The foreign object inlet is vertically fitted with a lower foreign object inlet valve 322 and an upper foreign object inlet valve 321 to prevent loop water leakage when a foreign object is introduced. The experimental section also includes an experimental section drain valve 332, an experimental section vent valve 331, and an experimental section outlet valve 342. These piping and connectors together form the experimental section module. The visual feedwater loop test section 33 is used to simulate a nuclear reactor. The steam generator has a secondary side feedwater ring pipe; downstream of the third flow regulating valve 34, there is a foreign matter collection tank 4 and a third Y-type filter 5, which are used to collect foreign matter leaving the experimental section during circulation; the connected high-speed camera 9, local area network computer 10 and storage device 11 form the system's image acquisition module, in which the high-speed camera 9 records the process of foreign matter entering and leaving the feedwater ring pipe in the experimental section, and the local area network computer 10 is connected to the high-speed camera 9, which can promptly provide feedback on the shooting results of the high-speed camera 9 and save the shooting results in the storage device 11, which is convenient for recording and archiving experimental results and post-processing of experimental data.

[0016] like Figure 2a , Figure 2b and Figure 2cAs shown, the visualized water supply ring test section 33 is made of plexiglass, which offers good safety and allows for visualization. The visualized water supply ring test section 33 includes an air vent valve 331, a drain valve 332, a top cover 333, a cylinder 334, a base 335, a descending section 336, a central pipe 337, and a water supply ring assembly composed of a water supply ring pipe 338 and an inverted J-shaped pipe 339. The top cover 333 is located at the top of the cylinder 334, sealing the test section, and has an air vent valve 331 on its upper part. The base 335 is located at the bottom of the cylinder 333 and has a drain valve 332. The central pipe 337 is located at the center of the cylinder 334, and together with the cylinder 334, it separates the descending section 336, allowing for water supply... The water ring pipe 338 surrounds the central pipe, and the upper part is equipped with inverted J-shaped pipes 339. The inlet and outlet of the visual water supply ring pipe test section require additional flange structures to connect with the main circulation loop pipe. Foreign objects enter from the inlet of the water supply ring pipe 338, pass through the inverted J-shaped pipe 339 and enter the descending section 336. Larger foreign objects sink to the bottom of the cylinder, while smaller foreign objects leave the test section through the central pipe 337. In actual installation, in order to ensure the stability of the test section, the structure in the visual water supply ring pipe test section is fixed with acrylic glue. Considering the disassembly and installation requirements, the top cover and base are designed as plate structures, and an exhaust valve 331 and a drain valve 332 are added to the test section.

[0017] like Figure 1As shown, this invention provides a visualization experiment scheme for the movement of foreign objects on the secondary side of a nuclear reactor steam generator. Before the experiment begins, the main circulation loop is filled with water for leak detection and anti-destruction tests to ensure that there are no leaks in the main circulation loop under high flow rates and that the experimental section remains intact and undamaged. When the main circulation loop is opened, the main valve 3, the experimental section outlet valve 34, and the experimental section exhaust valve 331 are kept open, while the bypass valve 2, the experimental section drain valve 332, the upper foreign object inlet valve 321, and the lower foreign object inlet valve 322 are kept closed. The double-suction pump 1 is started, and the experimental section exhaust valve 331 is closed after the experimental section is filled with water. When adjusting the circulation flow rate of the main circulation loop, the double-suction pump 1 is started, and the frequency of the frequency converter of the double-suction pump is adjusted according to the reading of the flow meter 31 until the design flow rate is reached. When adjusting the flow rate of the bypass loop, the bypass valve 2 is opened and its opening degree is adjusted. When conducting the experiment on the movement of foreign objects in the feedwater ring pipe of the nuclear reactor steam generator secondary side, the above steps are followed. After starting the main circulation loop, closing the bypass loop, and adjusting the fluid flow rate to the required experimental parameters, and once the main circulation loop is running stably, the experimental foreign object component is introduced. Simultaneously, the high-speed camera 9 is turned on to record the experimental process. When introducing the experimental foreign object component, the lower foreign object inlet valve 322 is closed, and the upper foreign object inlet valve 321 is opened. The foreign object is then introduced into the upper foreign object inlet, allowing it to fall into the inlet pipe. The upper foreign object inlet valve 321 is then closed, and the lower foreign object inlet valve 322 is opened, allowing the foreign object to fall into the circulating water loop pipe and enter the experimental section along with the circulating water. Simultaneously, the high-speed camera 9 is turned on, and the movement of the foreign object in the feed water ring pipe is observed and recorded using the local area network computer 10. After the experiment, the double-suction pump 1 is turned off, the shooting results are archived in the storage device 11, and the foreign objects are collected, organized, and documented in writing. The recovered foreign objects include those at the bottom of the experimental section sleeve and those in the experimental section outlet foreign object collection tank.

Claims

1. A real-time visualization and motion experimental system for foreign matter in the secondary feedwater loop of a nuclear reactor steam generator, characterized in that: The system includes a double-suction pump (1) on the main circulation loop and a bypass valve (2) connected in parallel with the double-suction pump, a first Y-type filter (8) on the upstream pipe of the double-suction pump (1), a water tank (7) on the upstream pipe of the first Y-type filter (8), a pressure gauge (6) installed on the inlet pipe of the water tank (1), a water injection valve (71) at the bottom of the water tank, and a level gauge (72) on one side of the water tank (7). The functions of the above components in the loop are to provide circulation power, regulate flow, filter the inlet fluid of the pump, stabilize the pressure of the liquid storage, monitor the pressure of the main circulation loop, replenish the water tank level, and monitor the water tank level. The above components constitute the main loop regulation and monitoring module of the system. A main valve (3) is connected to the downstream pipeline of the double-suction pump (1). The main valve (3) controls the flow of the entire circuit. A flow meter (31) is installed downstream of the main valve (3) to monitor the flow of the corresponding experimental section. A second Y-type filter (32) is installed downstream of the flow meter (31) to filter the fluid entering the experimental section and prevent the backflow and loss of foreign objects during the experiment. Downstream of the second Y-type filter (32) are a foreign object inlet consisting of a lower foreign object inlet valve (322) and an upper foreign object inlet valve (321), an experimental section inlet hose (341), a visual water supply loop experimental section (33), and an experimental section outlet. The hose (342) has a lower foreign object inlet valve (322) and an upper foreign object inlet valve (321) installed in the vertical direction to prevent leakage of the loop water when the valve is opened to put in foreign objects; the experimental section drain valve (332), the experimental section exhaust valve (331) and the experimental section outlet valve (34) installed on the experimental section outlet hose (342) are installed on the experimental section of the visual feedwater loop test section (33). The above system pipes and connectors together form the experimental section module. The visual feedwater loop test section (33) is used to simulate the secondary side feedwater loop of the nuclear reactor steam generator. Downstream of the third flow regulating valve (34) is a foreign matter collection tank (4) and a third Y-type filter (5) for collecting foreign matter leaving the experimental section during the circulation; The system's image acquisition module consists of a high-speed camera (9), a local area network computer (10), and a storage device (11) connected together. The high-speed camera (9) can be easily moved to clearly record the process of foreign objects entering and leaving the water supply ring pipe in the experimental section. The local area network computer (10) is connected to the high-speed camera (9) and can promptly provide feedback on the shooting results of the high-speed camera (9) and save the shooting results in the storage device (11) to facilitate the recording and archiving of experimental results and the post-processing of experimental data.

2. The experimental system for visualizing the flow of foreign matter in the secondary feedwater ring pipe of a nuclear reactor steam generator according to claim 1, characterized in that: The visualized water supply ring test section (33) is made of plexiglass and includes an air vent valve (331), a drain valve (332), a top cover (333), a cylinder (334), a base (335), a descending section (336), a central pipe (337), and a water supply ring assembly composed of a water supply ring pipe (338) and an inverted J-shaped pipe (339). The top cover (333) is located at the top of the cylinder (334) and serves to seal the test section. An air vent valve (331) is located at the top of the cylinder. The base (335) is located at the bottom of the cylinder (333) and has a drain valve (332). The central pipe (337) is located at the center of the cylinder (334), and together with the cylinder (334) separates the descending section (336). The water supply ring pipe (338) surrounds the central pipe, and the upper part is covered with inverted J-shaped pipes (339). The inlet and outlet of the visualized water supply ring pipe experimental section require additional flange structures to connect with the main circulation loop pipe. Foreign objects enter from the inlet of the water supply ring pipe (338), pass through the inverted J-shaped pipe (339) and enter the descending section (336). Foreign objects with larger mass sink to the bottom of the cylinder, and foreign objects with smaller mass leave the experimental section from the central pipe (337).

3. The experimental system for visualizing the flow of foreign matter in the secondary feedwater ring pipe of a nuclear reactor steam generator according to claim 2, characterized in that: In actual installation, to ensure the stability of the experimental section, the structure in the visualized water supply ring pipe experimental section is fixed with acrylic adhesive.

4. The experimental system for visualizing the flow of foreign matter in the secondary feedwater ring pipe of a nuclear reactor steam generator according to claim 2, characterized in that: To accommodate disassembly and installation requirements, the top cover and base are designed as plate structures.

5. The experimental system for visualizing the flow of foreign matter in the secondary feedwater ring pipe of a nuclear reactor steam generator according to claim 1, characterized in that: The high-speed camera (9) can be easily moved to clearly record the process of foreign objects entering and leaving the water supply ring pipe in the experimental section.

6. The experimental method corresponding to the experimental system according to any one of claims 1 to 5, characterized in that: Before the experiment, the main circulation loop was filled with water for leak detection and anti-destruction test to ensure that the main circulation loop had no leakage under high flow and that the test section was intact and undamaged. When the main circulation loop is opened, keep the main valve (3), the test section outlet valve (34), and the test section exhaust valve (331) in the open state, and keep the bypass valve (2), the test section drain valve (332), the upper foreign object inlet valve (321), and the lower foreign object inlet valve (322) in the closed state. Start the double suction pump (1), and close the test section exhaust valve (331) when the test section is filled with water. When adjusting the main circulation loop flow rate, turn on the double suction pump (1) and adjust the frequency of the double suction pump according to the reading of the flow meter (31) until the design flow rate is reached; When adjusting the flow rate of the bypass circuit, open the bypass valve (2) and adjust its opening degree; When conducting an experiment on the movement of foreign objects in the secondary feedwater loop of a nuclear reactor steam generator, after opening the main circulation loop and closing the bypass loop as described above, and adjusting the fluid flow rate to the required level, once the main circulation loop is running stably, the experimental foreign object element is placed in the loop. Simultaneously, the high-speed camera (9) is turned on to record the experimental process. When placing the experimental foreign object element, the lower foreign object placement valve (322) is closed, and the upper foreign object placement valve (321) is opened. The foreign object is then placed into the upper foreign object placement port, allowing it to fall into the placement port pipe. Then close the upper foreign object inlet valve (321) and open the lower foreign object outlet valve (322) to let the foreign object fall into the circulating water loop pipe and enter the experimental section with the circulating water; at the same time, turn on the high-speed camera (9) and use the local area network computer (10) to observe and record the movement process of the foreign object in the water supply ring pipe; after the experiment, turn off the double suction pump (1), archive the shooting results in the storage device (11), collect and sort the foreign objects and make written records; the recovered foreign objects include the foreign objects at the bottom of the experimental section sleeve and the foreign objects in the experimental section outlet foreign object collection tank.

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