A system and method for verifying a full-process nuclear power non-active pulse cooling

Abstract

The application discloses a system and method for verifying a whole-process nuclear power passive pulse cooling, and relates to the technical field of nuclear power, and can simulate a whole-plant power loss superimposed with a main feedwater loss accident of a nuclear power plant and verify a whole-process nuclear power passive pulse cooling process.

Description

Technical Field

[0001] This invention relates to the field of verification technology for severe accident mitigation measures in nuclear power plants, and in particular to a system and method for verifying passive pulse cooling throughout the entire nuclear power process. Background Technology

[0002] To address the issue that existing state-guided accident procedures (SOPs) for Generation II nuclear power plants are often only applicable to isolated plant-wide power outages (SBO) or loss of main feedwater (TLFW) accidents, and are insufficient to handle complex situations involving both, patent CN111370153A discloses a passive pulse cooling method. This method proposes a novel passive pulse cooling approach, dividing the evaporator into a powered evaporator (SG1, SG3) and a cooling evaporator (SG2). The cooling evaporator is depressurized, and high-pressure steam from the steam pipes and powered evaporator is used as a passive driving force to inject water stored in the depressurized cooling evaporator. This achieves the injection of high-temperature, high-pressure water into the steam generator to cool the primary loop, mitigating accident hazards and reducing the likelihood of core meltdown.

[0003] This method has high novelty and practical implementation potential, but the actual modification of nuclear power plants still requires rigorous experimental verification under a standardized scale to prove the reliability of the method. Currently, there is a lack of verification schemes, which makes it difficult to transform this engineering concept into practical applications. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a system and method for verifying passive pulse cooling of the entire nuclear power process.

[0005] The technical solution adopted by this invention to solve its technical problem is: constructing a system for verifying passive pulse cooling of the entire nuclear power process, comprising: The primary loop system is used to provide high-temperature, high-pressure water; At least three steam generator simulators, each of which has its primary side connected to the primary loop system and its secondary side equipped with a discharge valve and a steam pipe; The secondary loop system includes a deaerator, the outlet of which is connected to the secondary side of each steam generator simulator via a water supply pipe, and the steam pipe is connected to the secondary side of the steam generator simulator and the pressurization port of the deaerator. At least one of the steam generator simulators is configured as a cooling steam generator, and the rest are configured as power steam generators. The high-pressure steam generated on the secondary side of the power steam generator enters the deaerator through the steam pipe, driving the feedwater in the deaerator to be injected into the secondary side of the cooling steam generator. The injected feedwater is heated and vaporized, causing the secondary side pressure to rise. Together with the continuous pressure relief of the discharge valve, a cyclic pulse process of feedwater injection, interruption, and injection is formed. The measurement system is used to collect pressure, temperature, and flow data of the system used to verify the passive pulse cooling process of the entire nuclear power plant.

[0006] Furthermore, the primary loop system is a closed loop, comprising a first pressurized water tank, a shielded pump, a throttling orifice plate, a preheating section, a primary side branch of each of the steam generator simulators, and a condenser connected in sequence, and flowing back to the first pressurized water tank; The cooling side of the condenser is connected to a cooling system for cooling the high-temperature, high-pressure water of the primary loop system during non-pulse phases to maintain the stability of the experimental conditions.

[0007] Furthermore, in the dual-loop system, a one-way check valve is provided on the water supply pipeline between the outlet of the deaerator and the secondary inlet of the steam generator simulator to prevent steam backflow and ensure the unidirectionality of the passive drive path; a pressure reducing valve is provided on the steam pipeline between the secondary outlet of the power steam generator and the pressurization port of the deaerator to adjust the steam pressure to match the verification operating conditions.

[0008] Furthermore, the secondary loop system also includes a second pressurized water tank for supplying water to the deaerator; the deaerator is equipped with a heating rod to heat the water to saturation; the pressurization port of the deaerator is located at the upper end of the deaerator to achieve gas-side pressurization, or at the lower end of the deaerator to achieve water-side pressurization.

[0009] Furthermore, all the steam generator simulation components are set at the same horizontal height and located at the highest position in the closed loop of the primary loop system, while the preheating section is located at the lowest position in the closed loop of the primary loop system, in order to establish the height difference required for natural circulation and to verify the natural circulation cooling effect under the power failure condition of the entire plant.

[0010] Furthermore, the steam generator simulator is equipped with a U-shaped tube made of stainless steel or Inconel material; the opening degree of the discharge valve is adjustable to simulate the opening state of different numbers of bypass atmospheric discharge valves in a nuclear power plant.

[0011] Furthermore, the measurement system includes: Pressure measurement unit, temperature measurement unit and flow measurement unit are installed in the primary loop system; Pressure measurement unit, temperature measurement unit and flow measurement unit are installed on the primary side of each of the steam generator simulators; Pressure measurement unit, temperature measurement unit and flow measurement unit are installed in the dual-loop system; Pressure and temperature measurement units are installed on the secondary side of each of the steam generator simulators; Temperature measurement units are installed on the pipe walls of each of the steam generator simulators; The pressure measuring unit before and after the pressure reducing valve.

[0012] This invention also constructs a method for verifying passive pulse cooling of the entire nuclear power process, using the system for verifying passive pulse cooling of the entire nuclear power process described in any of the above claims, comprising the following steps: S10: A high-temperature and high-pressure water circulation is established through a primary loop system, so that the primary side of each of the steam generator simulation components reaches the preset temperature and pressure; S20: Configure at least one of the steam generator simulators as a cooling steam generator and the rest as power steam generators, and open the discharge valve of the cooling steam generator to release pressure; S30: Feedwater is injected into the secondary side of the power steam generator through the secondary loop system, and the feedwater is heated by the high temperature and high pressure water flowing through the primary side of the power steam generator, so that the feedwater is vaporized to generate high pressure steam. S40: Through the secondary loop system, the high-pressure steam generated by the power steam generator is introduced into the deaerator through the steam pipeline, and the feedwater in the deaerator is injected into the secondary side of the cooling steam generator through the feedwater pipeline. S50: The measurement system collects pressure, temperature and flow data in real time, observes and records the cooling process of the primary loop system, the steam generation and driving process of the power steam generator, and the cyclic pulse process of secondary side water injection, interruption and injection of the cooling steam generator.

[0013] Furthermore, in step S10, the high-temperature and high-pressure water circulation is established by forced circulation or natural circulation; The forced circulation is to start the shielded pump of the primary loop system to drive water circulation; The natural circulation involves creating a height difference between the preheating section of the primary loop system and the steam generator simulator, with the preheating section at a low position and the steam generator simulator at a high position. Cooling is provided to the secondary side of the steam generator simulator by the secondary loop system. Once the water temperature of the primary loop system reaches a predetermined temperature, the shielded pump is stopped, and circulation is maintained by density difference.

[0014] Furthermore, the data collected by the measurement system in step S50 includes: The pressure, temperature, and flow rate of the primary loop system; Pressure, temperature, and flow rate on the primary side of each of the aforementioned steam generator simulators; The pressure, temperature, and flow rate of the dual-loop system; Pressure and temperature on the secondary side of each of the steam generator simulators; The temperature of the pipe wall of each of the steam generator simulators; The pressure before and after the pressure reducing valve on the steam pipeline.

[0015] By implementing this invention, the following beneficial effects are achieved: This invention provides a system for verifying the passive pulse cooling process of a nuclear power plant throughout the entire process. It provides high-temperature, high-pressure water through the primary loop system to simulate the core thermal conditions under accident scenarios. At least three steam generator simulators are used, with at least one configured as a cooling steam generator and the rest as power steam generators. This accurately simulates the steam output of the power steam generators, the cooling effect of the cooling steam generators, and the interaction and feedback between them, realistically reflecting the prototype parameters. A passively driven feedwater transmission path is established through the deaerator, feedwater pipeline, and steam pipeline of the secondary loop system. Pressure, temperature, and flow data of the entire system are collected through a measurement system to verify the passive pulse cooling process of the entire nuclear power plant. This invention can simulate a nuclear power plant-wide power outage coupled with the loss of main feedwater, serving as an engineering experimental device to directly verify the feasibility of the passive pulse cooling method in nuclear power plants, providing methodological feasibility support for the retrofitting and operation of existing Generation II nuclear power plants.

[0016] The present invention verifies the passive pulse cooling method for the entire nuclear power plant process. It establishes a high-temperature, high-pressure water circulation in the primary loop system, bringing the primary side of each steam generator simulator to a preset temperature and pressure to simulate the core thermal conditions under accident conditions. At least one steam generator simulator is configured as a cooling steam generator, and the rest as power steam generators. The exhaust valve of the cooling steam generator is opened to release pressure, establishing the pressure differential required for drive. Feedwater is injected into the secondary side of the power steam generators through the secondary loop system. The high-temperature, high-pressure water flowing through the primary side of the power steam generator heats the feedwater, causing it to vaporize and generate high-pressure steam, converting the heat from the primary loop into passive driving force. The high-pressure steam generated by the power steam generator is introduced into the deaerator, increasing the internal pressure and driving the feedwater in the deaerator to inject into the secondary side of the cooling steam generator, achieving passive feedwater control. Data is collected in real time through a measurement system to observe and record the cooling process of the primary loop system, the steam generation and driving process of the power steam generator, and the cyclic pulse process of feedwater injection, interruption, and injection into the secondary side of the cooling steam generator. This method fully reproduces the cyclic pulse process of feedwater injection, interruption, and injection. The key data collected by the measurement system can directly verify the reliability of the passive pulse cooling method, providing experimental support for the improvement of the SOP procedures of existing second-generation nuclear power plants. Attached Figure Description

[0017] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings: Figure 1 This is a schematic diagram of the first loop of the system for verifying the passive pulse cooling of the entire nuclear power plant process according to Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of the secondary loop of the system for verifying the passive pulse cooling of the entire nuclear power plant process according to Embodiment 1 of the present invention; Figure 3 This is a schematic diagram of a gas-side pressurization structure according to an embodiment of the present invention; Figure 4 This is a schematic diagram of a water-side pressurization structure according to an embodiment of the present invention; Among them: 1-1, First steam generator simulator; 1-2, Second steam generator simulator; 1-3, Third steam generator simulator; 2-1, First pressure sensor; 2-2, Second pressure sensor; 2-3, Third pressure sensor; 2-4, Fourth pressure sensor; 2-5, Fifth pressure sensor; 2-6, Sixth pressure sensor; 2-7, Seventh pressure sensor; 2-8, Eighth pressure sensor; 2-9, Ninth pressure sensor; 2-10, Tenth pressure sensor; 2-11, Eleventh pressure sensor; 2-12, Twelfth pressure sensor; 2-13, Thirteenth pressure sensor; 2-14, Fourteenth pressure sensor; 2-15, Fifteenth pressure sensor; 2-16, Sixteenth pressure sensor; Pressure sensor; 2-17, Seventeenth pressure sensor; 3-1, First thermocouple; 3-2, Second thermocouple; 3-3, Third thermocouple; 3-4, Fourth thermocouple; 3-5, Fifth thermocouple; 3-6, Sixth thermocouple; 3-7, Seventh thermocouple; 3-8, Eighth thermocouple; 3-9, Ninth thermocouple; 3-10, Tenth thermocouple; 3-11, Eleventh thermocouple; 3-12, Twelfth thermocouple; 4-1, First electric shut-off valve; 4-2, Second electric shut-off valve; 4-3, Third electric shut-off valve; 5, Condenser; 6-1, First pressurized water tank; 6-2, Second pressurized water tank; 7-1, First regulating valve; 7-2, Second regulating valve; 7-3, Third regulating valve; 7-4, Fourth regulating valve Valves; 7-5, Fifth regulating valve; 7-6, Sixth regulating valve; 7-7, Seventh regulating valve; 7-8, Eighth regulating valve; 7-9, Ninth regulating valve; 7-10, Tenth regulating valve; 7-11, Eleventh regulating valve; 7-12, Twelfth regulating valve; 7-13, Thirteenth regulating valve; 7-14, Fourteenth regulating valve; 7-15, Fifteenth regulating valve; 7-16, Sixteenth regulating valve; 7-17, Seventeenth regulating valve; 7-18, Eighteenth regulating valve; 7-19, Nineteenth regulating valve; 7-20, Twentieth regulating valve; 7-21, Twenty-first regulating valve; 7-22, Twenty-second regulating valve; 7-23, Twenty-third regulating valve; 7-24, Twenty-fourth regulating valve; 8, Shielded pump; 9, Preheating section; 10-1, First liquid mass flow meter; 10-2, Second liquid mass flow meter; 10-3, Third liquid mass flow meter; 10-4, Fourth liquid mass flow meter; 10-5, Fifth liquid mass flow meter; 10-6, Sixth liquid mass flow meter; 10-7, Seventh liquid mass flow meter; 11, Open water tank; 12, Circulating pump; 13, Filter; 14, Cooling tower; 15-1, First discharge valve; 15-2, Second discharge valve; 15-3, Third discharge valve; 16-1, First gas mass flow meter; 16-2, Second gas mass flow meter; 16-3, Third gas mass flow meter; 17, Pressure reducing valve; 18, Deaerator; 19, Orifice plate; 20-1, First one-way check valve;20-2, Second one-way check valve; 20-3, Third one-way check valve. Detailed Implementation

[0018] To provide a clearer understanding of the technical features, objectives, and effects of the present invention, specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0019] Example 1: See Figures 1 to 4 One embodiment of the present invention discloses a system for verifying passive pulse cooling of the entire nuclear power process, including a primary loop system, at least three steam generator simulators, a secondary loop system, and a measurement system.

[0020] like Figure 1 As shown, the primary loop system provides high-temperature, high-pressure water to simulate the reactor coolant system of a nuclear power plant. The primary loop system is a closed-loop system, comprising, in sequence, a first pressurized water tank 6-1, a shielded pump 8, an orifice plate 19, a preheating section 9, a primary side branch of each steam generator simulator, and a condenser 5. The outlet of the condenser 5 is connected to the inlet of the first pressurized water tank 6-1. The first pressurized water tank 6-1 is used to stabilize the primary loop water supply; its design pressure is above 17 MPa, its effective volume is above 2 m³, and it has built-in electric heating rods to simulate the function of the pressurizer in the prototype nuclear power plant. The shielded pump 8 drives the water circulation in the primary loop system; its design pressure is above 17 MPa. The orifice plate 19 is used to regulate the pressure drop in the primary loop. Given the power of the preheating section 9 and the saturation temperature and flow rate of the feedwater injected into the steam generator simulator, the mass flow rate of the primary loop is adjusted through the orifice plate 19 to match the experimental conditions with the prototype. Preheating section 9 is used to simulate the heat source of core decay, heating the primary circuit water to a preset temperature. Its design pressure is above 17MPa and the maximum operating temperature is 400℃.

[0021] A cooling system is connected to the cooling side of condenser 5 to cool the high-temperature, high-pressure water of the primary loop system during non-pulse phases, thereby maintaining the stability of the experimental conditions. The high-temperature, high-pressure water here refers to the primary loop high-temperature, high-pressure water flowing out from the primary side outlet of the steam generator simulator. This system can cool the primary loop high-temperature, high-pressure water even when deaerator 18 is not supplying water to the steam generator simulator, ensuring that the canned pump 8 operates within its permissible operating temperature range. The cooling system includes an open water tank 11, a circulating pump 12, and a cooling tower 14 connected in sequence. The inlet of the open water tank 11 is connected to the outlet of the cooling tower 14, forming a closed cooling loop.

[0022] The number of steam generator simulators is at least three, for example, a first steam generator simulator 1-1, a second steam generator simulator 1-2, and a third steam generator simulator 1-3. The primary side of each steam generator simulator is connected to the primary loop system, and the secondary side of each simulator is equipped with a vent valve and steam piping. Each steam generator simulator contains a U-tube made of stainless steel or Inconel. Stainless steel is less expensive, while Inconel better reflects the heat transfer of the prototype and allows for additional examination of the structural strength of the steam generator during extreme pulse cooling. The vent valve opening is adjustable and is used to simulate the bypass atmospheric vent valves of a nuclear power plant. By adjusting the opening, different states of opening of 0 to 7 bypass atmospheric vent valves in the prototype nuclear power plant can be simulated.

[0023] like Figure 2 As shown, the secondary loop system includes a deaerator 18, a second pressurized water tank 6-2, a water supply pipeline, and a steam pipeline. The second pressurized water tank 6-2 supplies water to the deaerator 18, with a design pressure of 2 MPa or higher and an effective volume of 5 m³ or higher. The deaerator 18 is equipped with a heating rod to heat the water to saturation. The outlet of the deaerator 18 is connected to the secondary side of each steam generator simulator via water supply pipelines. One-way check valves are installed on the water supply pipelines to prevent steam backflow into the deaerator 18 when the pressure inside the steam generator simulator increases, ensuring the unidirectional nature of the passive drive path. The steam pipelines connect the secondary side of the steam generator simulator to the pressurization port of the deaerator 18. Pressure reducing valves 17 are installed on the steam pipelines to regulate the steam pressure entering the deaerator 18 to match the verification operating conditions.

[0024] The pressurization port of deaerator 18 has two settings: such as Figure 3 As shown, it is positioned at the upper end of the deaerator 18 to achieve gas-side pressurization, that is, saturated steam is injected from the upper end of the deaerator 18 and directly introduced into the saturated steam space at the upper end of the deaerator 18. Or as... Figure 4 As shown, a water-side pressurization system is installed at the lower end of the deaerator 18, meaning that saturated steam is injected from the lower end of the deaerator 18 and directly enters the saturated water space at the lower end of the deaerator 18. These two driving methods, gas-side pressurization and water-side pressurization, provide a basis for adapting to different nuclear reactor building modifications and enrich the verifiable operating conditions.

[0025] In this embodiment, at least one steam generator simulator is configured as a cooling steam generator, such as the third steam generator simulator 1-3, while the others are configured as power steam generators, such as the first steam generator simulator 1-1 and the second steam generator simulator 1-2. High-pressure steam generated on the secondary side of the power steam generator enters the deaerator 18 through a steam pipeline, driving the feedwater in the deaerator 18 to inject into the secondary side of the cooling steam generator. The feedwater injected into the secondary side of the cooling steam generator is heated by the high-temperature, high-pressure water from the primary loop and vaporizes, causing an increase in secondary side pressure. This, combined with the continuous pressure relief from the discharge valve, forms a cyclic pulse process of feedwater injection, interruption, and injection. This pulse process achieves passive cooling, verifying that under the condition of a plant-wide power outage and loss of main feedwater, the coordinated operation of multiple steam generators can effectively remove residual core heat.

[0026] The high-pressure steam generated on the secondary side of the power steam generator enters the deaerator 18 through the steam pipeline, driving the feedwater in the deaerator 18 to be injected into the secondary side of the cooling steam generator. The injected feedwater is heated and vaporized, causing the secondary side pressure to rise. Together with the continuous pressure relief of the discharge valve, a cyclic pulse process of feedwater injection, interruption, and injection is formed.

[0027] To achieve accurate measurement and verification of the above process, this system also includes a measurement system for collecting pressure, temperature, and flow data of the system used to verify the entire passive pulse cooling process of nuclear power plants. The measurement system includes: Pressure, temperature, and flow measurement units installed in the primary loop system are used to monitor the pressure, temperature, and flow rate of the primary loop main pipeline to verify the cooling effect. Pressure, temperature, and flow measurement units installed on the primary side of each steam generator simulator are used to monitor the pressure, temperature, and flow rate entering and leaving the primary side of each steam generator to verify flow distribution and heat transfer characteristics. Pressure, temperature, and flow measurement units installed in the secondary loop system are used to monitor the pressure, temperature, and flow rate of the feedwater pipeline to verify passive drive conditions. Pressure and temperature measurement units installed on the secondary side of each steam generator simulator are used to monitor the internal pressure and temperature of the secondary side to capture pulse phenomena. Temperature measurement units installed on the pipe wall of each steam generator simulator are used to monitor the U-tube wall temperature to evaluate heat transfer effect and structural safety. Pressure measurement units installed before and after pressure reducing valve 17 are used to monitor the pressure before and after pressure reducing valve 17 to verify whether the pressure regulation of the driving steam meets the requirements.

[0028] The temperature measurement unit includes thermocouples, which can be high-temperature resistant thermocouples, with a temperature measurement range covering 0℃ to 300℃. The pressure measurement unit includes pressure sensors; the primary pressure sensor has a pressure measurement range covering 0MPa to 15MPa, and the secondary pressure sensor has a pressure measurement range covering 0MPa to 2MPa. The flow measurement unit includes flow meters; depending on the type of fluid being monitored, liquid mass flow meters and gas mass flow meters can be used to measure water flow and steam flow, respectively.

[0029] The following is a specific application of the system for verifying the passive pulse cooling process of nuclear power plants in this embodiment: like Figure 1 and Figure 2 As shown, the system for verifying the passive pulse cooling of the entire nuclear power plant process includes three steam generator simulators: the first steam generator simulator 1-1, the second steam generator simulator 1-2, and the third steam generator simulator 1-3. The first steam generator simulator 1-1 and the second steam generator simulator 1-2 serve as power steam generators, while the third steam generator simulator 1-3 serves as a cooling steam generator.

[0030] like Figure 1 As shown, the primary loop system is specifically configured as follows: The outlet of the first pressurized water tank 6-1 is connected to the inlet of the canned motor pump 8 via a pipeline, on which a first regulating valve 7-1 is installed. The outlet of the canned motor pump 8 is connected to the inlet of the orifice plate 19, and a second regulating valve 7-2 is installed on the pipeline between them. The outlet of the orifice plate 19 is connected to the inlet of the preheating section 9. The outlet of the preheating section 9 is branched into three branches via a main pipeline, which are respectively connected to the primary side inlet of the first steam generator simulator 1-1, the primary side inlet of the second steam generator simulator 1-2, and the primary side inlet of the third steam generator simulator 1-3. A second electric shut-off valve 4-2 is installed on the main pipeline to control the flow path of the main pipeline at the outlet of the preheating section 9. A third regulating valve 7-3 and a fourth regulating valve 7-4 are installed in parallel on the primary side inlet branch of the first steam generator simulator 1-1. A fifth regulating valve 7-5 and a sixth regulating valve 7-6 are installed in parallel on the primary side inlet branch of the second steam generator simulator 1-2. The primary inlet branch of the third steam generator simulator 1-3 is equipped with a seventh regulating valve 7-7 and an eighth regulating valve 7-8 connected in parallel. The primary outlets of the first steam generator simulator 1-1, the second steam generator simulator 1-2, and the third steam generator simulator 1-3 are merged into a main pipeline via branch pipes, which connects to the inlet of the condenser 5. A first electric shut-off valve 4-1 is installed on the merged main pipeline. The outlet of the condenser 5 is connected to the inlet of the first pressurized water tank 6-1, and the outlet of the first pressurized water tank 6-1 is connected to the inlet of the canned motor pump 8, forming a closed loop.

[0031] The cooling side of the condenser 5 is connected to a cooling system, which includes an open water tank 11, a circulating pump 12, a third electric shut-off valve 4-3, a filter 13, a ninth regulating valve 7-9, and a cooling tower 14. Room temperature water in the open water tank 11 is driven by the circulating pump 12, filtered by the filter 13, and enters the condenser 5 to cool the high-temperature, high-pressure water in the first loop. After flowing out of the condenser 5, the water reaches the cooling tower 14 to exchange heat with the environment and then returns to the open water tank 11, forming a closed cooling loop.

[0032] The specific configuration of the two-loop system is as follows: The outlet of the second pressurized water tank 6-2 is connected to the water supply inlet of the deaerator 18 via a pipeline. The outlet of the deaerator 18 is connected to the twenty-fourth regulating valve 7-24 via a water supply pipeline, and then splits into three branch pipes, which are respectively connected to the secondary side inlet of the first steam generator simulator 1-1, the secondary side inlet of the second steam generator simulator 1-2, and the secondary side inlet of the third steam generator simulator 1-3. The secondary side inlet branch pipe of the first steam generator simulator 1-1 is equipped with a tenth regulating valve 7-10 and an eleventh regulating valve 7-11 connected in parallel. The secondary side inlet branch pipe of the second steam generator simulator 1-2 is equipped with a twelfth regulating valve 7-12 and a thirteenth regulating valve 7-13 connected in parallel. The secondary side inlet branch pipe of the third steam generator simulator 1-3 is equipped with a fourteenth regulating valve 7-14 and a fifteenth regulating valve 7-15 connected in parallel. One-way check valves are installed on the water supply pipes between the outlet of the deaerator 18 and the secondary side inlet of each steam generator simulator to prevent steam backflow. These include a first one-way check valve 20-1 at the secondary side inlet of the first steam generator simulator 1-1, a second one-way check valve 20-2 at the secondary side inlet of the second steam generator simulator 1-2, and a third one-way check valve 20-3 at the secondary side inlet of the third steam generator simulator 1-3.

[0033] The secondary outlet of the first steam generator simulator 1-1 is connected to the first steam pipeline. The first steam pipeline is equipped with a first discharge valve 15-1 and a sixteenth regulating valve 7-16, and a seventeenth regulating valve 7-17 connected in parallel with the sixteenth regulating valve 7-16 for standby. The secondary outlet of the second steam generator simulator 1-2 is connected to the second steam pipeline. The second steam pipeline is equipped with a second discharge valve 15-2 and an eighteenth regulating valve 7-18, and a nineteenth regulating valve 7-19 connected in parallel with the eighteenth regulating valve 7-18 for standby. The secondary outlet of the third steam generator simulator 1-3 is connected to the third steam pipeline. The third steam pipeline is equipped with a third discharge valve 15-3 and a twentieth regulating valve 7-20, and a twenty-first regulating valve 7-21 connected in parallel with the twentieth regulating valve 7-20 for standby. The first, second, and third steam pipelines merge into a main steam pipeline. The main steam pipeline is equipped with a pressure reducing valve 17, and the outlet of the pressure reducing valve 17 is connected to the pressurization port of the deaerator 18 via a pipeline. The main steam pipeline is equipped with a twenty-second regulating valve 7-22 before the pressure reducing valve 17 and a twenty-third regulating valve 7-23 after the pressure reducing valve 17, for regulating the steam flow.

[0034] The measurement system is specifically configured as follows: like Figure 1 As shown, the pressure measurement unit, temperature measurement unit, and flow measurement unit installed in the primary loop system include: a fourth pressure sensor 2-4 and a fifth thermocouple 3-5 installed at the outlet of the preheating section 9; a first liquid mass flow meter 10-1 installed on the main pipeline of the primary loop system, preferably located at the outlet of the preheating section 9; and a fourth thermocouple 3-4 installed at the outlet of the orifice plate 19. The fourth pressure sensor 2-4 is used to monitor the outlet pressure of the preheating section 9, the fifth thermocouple 3-5 is used to monitor the outlet temperature of the preheating section 9, the first liquid mass flow meter 10-1 is used to measure the total flow rate of the primary loop system, and the fourth thermocouple 3-4 is used to monitor the outlet temperature of the orifice plate 19.

[0035] like Figure 1As shown, the pressure measurement unit, temperature measurement unit, and flow measurement unit installed on the primary side of each steam generator simulator include: a fifth pressure sensor 2-5 and a sixth thermocouple 3-6 installed at the primary side inlet of the first steam generator simulator 1-1, and a first pressure sensor 2-1 and a first thermocouple 3-1 installed at the primary side outlet of the first steam generator simulator 1-1; and a second liquid mass flow meter 10-2 installed at the primary side inlet of the first steam generator simulator 1-1. Specifically, the fifth pressure sensor 2-5 monitors the primary side inlet pressure of the first steam generator simulator 1-1, the sixth thermocouple 3-6 monitors the primary side inlet temperature of the first steam generator simulator 1-1, the first pressure sensor 2-1 monitors the primary side outlet pressure of the first steam generator simulator 1-1, the first thermocouple 3-1 monitors the primary side outlet temperature of the first steam generator simulator 1-1, and the second liquid mass flow meter 10-2 measures the flow rate flowing into the primary side of the first steam generator simulator 1-1.

[0036] A sixth pressure sensor 2-6 and a seventh thermocouple 3-7 are installed at the primary side inlet of the second steam generator simulator 1-2, and a second pressure sensor 2-2 and a second thermocouple 3-2 are installed at the primary side outlet of the second steam generator simulator 1-2; a third liquid mass flow meter 10-3 is installed at the primary side inlet of the second steam generator simulator 1-2. The sixth pressure sensor 2-6 monitors the primary side inlet pressure of the second steam generator simulator 1-2, the seventh thermocouple 3-7 monitors the primary side inlet temperature of the second steam generator simulator 1-2, the second pressure sensor 2-2 monitors the primary side outlet pressure of the second steam generator simulator 1-2, the second thermocouple 3-2 monitors the primary side outlet temperature of the second steam generator simulator 1-2, and the third liquid mass flow meter 10-3 measures the flow rate flowing into the primary side of the second steam generator simulator 1-2.

[0037] A seventh pressure sensor 2-7 and an eighth thermocouple 3-8 are installed at the primary side inlet of the third steam generator simulator 1-3, and a third pressure sensor 2-3 and a third thermocouple 3-3 are installed at the primary side outlet of the third steam generator simulator 1-3; a fourth liquid mass flow meter 10-4 is installed at the primary side inlet of the third steam generator simulator 1-3. The seventh pressure sensor 2-7 monitors the primary side inlet pressure of the third steam generator simulator 1-3, the eighth thermocouple 3-8 monitors the primary side inlet temperature of the third steam generator simulator 1-3, the third pressure sensor 2-3 monitors the primary side outlet pressure of the third steam generator simulator 1-3, the third thermocouple 3-3 monitors the primary side outlet temperature of the third steam generator simulator 1-3, and the fourth liquid mass flow meter 10-4 measures the flow rate flowing into the primary side of the third steam generator simulator 1-3.

[0038] like Figure 2 As shown, the pressure measurement unit, temperature measurement unit, and flow measurement unit installed in the secondary loop system include: an eighth pressure sensor 2-8 and a ninth thermocouple 3-9 installed on the feedwater pipeline at the outlet of the deaerator 18; a twelfth pressure sensor 2-12 installed before the pressure reducing valve 17 on the main steam pipeline; a thirteenth pressure sensor 2-13 installed after the pressure reducing valve 17 on the main steam pipeline; and a fourteenth pressure sensor 2-14 installed inside the deaerator 18. Specifically, the eighth pressure sensor 2-8 is used to monitor the feedwater pipeline pressure, the ninth thermocouple 3-9 is used to monitor the feedwater temperature, the twelfth pressure sensor 2-12 is used to monitor the pressure before the pressure reducing valve 17, the thirteenth pressure sensor 2-13 is used to monitor the pressure after the pressure reducing valve 17, and the fourteenth pressure sensor 2-14 is used to monitor the internal pressure of the deaerator 18.

[0039] like Figure 2 As shown, the pressure measurement unit and flow measurement unit installed on the secondary side of each steam generator simulator include: A ninth pressure sensor 2-9 and a first gas mass flow meter 16-1 are installed on the first steam pipe at the secondary side outlet of the first steam generator simulator 1-1; a fifteenth pressure sensor 2-15 is installed inside the secondary side of the first steam generator simulator 1-1; and a fifth liquid mass flow meter 10-5 is installed on the secondary side inlet branch pipe of the first steam generator simulator 1-1. Specifically, the ninth pressure sensor 2-9 monitors the pressure of the first steam pipe; the first gas mass flow meter 16-1 measures the steam flow rate at the secondary side outlet of the first steam generator simulator 1-1; the fifteenth pressure sensor 2-15 monitors the internal pressure of the secondary side of the first steam generator simulator 1-1; and the fifth liquid mass flow meter 10-5 monitors the water flow rate at the secondary side inlet of the first steam generator simulator 1-1.

[0040] A tenth pressure sensor 2-10 and a second gas mass flow meter 16-2 are installed on the second steam pipe at the secondary side outlet of the second steam generator simulator 1-2; a sixteenth pressure sensor 2-16 is installed inside the secondary side of the second steam generator simulator 1-2; and a sixth liquid mass flow meter 10-6 is installed on the secondary side inlet branch pipe of the second steam generator simulator 1-2. Specifically, the tenth pressure sensor 2-10 monitors the pressure of the second steam pipe; the second gas mass flow meter 16-2 measures the steam flow rate at the secondary side outlet of the second steam generator simulator 1-2; the sixteenth pressure sensor 2-16 monitors the internal pressure of the secondary side of the second steam generator simulator 1-2; and the sixth liquid mass flow meter 10-6 monitors the secondary side inlet water flow rate of the second steam generator simulator 1-2.

[0041] Eleventh pressure sensor 2-11 and third gas mass flow meter 16-3 are installed on the third steam pipe at the secondary side outlet of the third steam generator simulator 1-3; seventeenth pressure sensor 2-17 is installed inside the secondary side of the third steam generator simulator 1-3; and seventh liquid mass flow meter 10-7 is installed on the secondary side inlet branch pipe of the third steam generator simulator 1-3. The eleventh pressure sensor 2-11 monitors the pressure of the third steam pipe; the third gas mass flow meter 16-3 measures the steam flow rate at the secondary side outlet of the third steam generator simulator 1-3; the seventeenth pressure sensor 2-17 monitors the internal pressure of the secondary side of the third steam generator simulator 1-3; and the seventh liquid mass flow meter 10-7 monitors the secondary side inlet water flow rate of the third steam generator simulator 1-3.

[0042] like Figure 2 As shown, the temperature measurement unit installed on the tube wall of each steam generator simulator includes: a tenth thermocouple 3-10 installed at the contact position between the U-tube and the tube sheet of the first steam generator simulator 1-1; an eleventh thermocouple 3-11 installed at the contact position between the U-tube and the tube sheet of the second steam generator simulator 1-2; and a twelfth thermocouple 3-12 installed at the contact position between the U-tube and the tube sheet of the third steam generator simulator 1-3. The tenth thermocouple 3-10 is used to monitor the U-tube wall temperature of the first steam generator simulator 1-1, the eleventh thermocouple 3-11 is used to monitor the U-tube wall temperature of the second steam generator simulator 1-2, and the twelfth thermocouple 3-12 is used to monitor the U-tube wall temperature of the third steam generator simulator 1-3.

[0043] like Figure 2 As shown, the pressure measuring unit installed before and after the pressure reducing valve includes a twelfth pressure sensor 2-12 installed before the pressure reducing valve 17 on the main steam pipeline and a thirteenth pressure sensor 2-13 installed after the pressure reducing valve 17 on the main steam pipeline. The twelfth pressure sensor 2-12 monitors the pressure before the pressure reducing valve 17, and the thirteenth pressure sensor 2-13 monitors the pressure after the pressure reducing valve 17 to verify whether the pressure regulation of the driving steam meets the requirements.

[0044] For the specific application method of this embodiment, please refer to Embodiment 2.

[0045] Example 2: This invention also constructs a method for verifying passive pulse cooling of the entire nuclear power process, using the system for verifying passive pulse cooling of the entire nuclear power process described in Embodiment 1 above, including the following steps: S10: A high-temperature, high-pressure water circulation is established through a primary loop system, enabling the primary side of each steam generator simulator to reach the preset temperature and pressure. The high-temperature, high-pressure water circulation can be established through forced circulation or natural circulation.

[0046] Forced circulation involves starting the canned motor pump of the primary loop system to drive water circulation. Specifically, the first regulating valve 7-1 at the outlet of the first pressurized water tank 6-1 is opened, the canned motor pump 8 is started, and the speed of the canned motor pump 8 is adjusted to a preset value, allowing the primary loop water to enter the preheating section 9 through the orifice plate 19. The preheating section 9 is started, and its power is gradually increased in steps to heat the primary loop water to the preset temperature. By adjusting the regulating valves on the primary side inlet branch pipes of each steam generator simulator, the flow distribution of each branch is made to meet the experimental operating conditions. After heat exchange on the primary side of each steam generator simulator, the primary loop water enters the condenser 5 through the first electric shut-off valve 4-1, is cooled by the cooling system, and then flows back to the first pressurized water tank 6-1, completing the closed loop. During this process, the pressure and temperature at the outlet of preheating section 9 are monitored by the fourth pressure sensor 2-4 and the fifth thermocouple 3-5 installed at the outlet of preheating section 9. The total flow rate of the primary loop is monitored by the first liquid mass flow meter 10-1 installed on the main pipeline of the primary loop system. The inlet parameters of each branch are monitored by the pressure sensor, temperature sensor and flow meter installed at the primary side inlet of each steam generator simulator. The outlet parameters of each branch are monitored by the pressure sensor and temperature sensor installed at the primary side outlet of each steam generator simulator. When the pressure, temperature and flow rate of the primary loop and each branch reach the preset steady-state value, the forced cycle is established.

[0047] Natural circulation creates a height difference between the preheating section 9 and the steam generator simulator in the primary loop system, placing the preheating section 9 at a lower position and the steam generator simulator at a higher position. Cooling is supplied to the secondary side of the steam generator simulator by the secondary loop system. Once the water temperature in the primary loop system reaches a predetermined temperature, the canned pump 8 is stopped, and circulation is maintained by density difference. Specifically, a high-pressure primary loop environment is first established by the canned pump 8. The preheating section 9 is then started to gradually increase the water temperature in the primary loop system. Simultaneously, feedwater is injected into the secondary side of the power steam generator through the secondary loop system. The steam generated by the power steam generator is discharged through the exhaust valve, allowing the steam generator simulator to act as a cold source absorbing heat from the primary loop. The outlet pressure and temperature of the preheating section 9 are monitored by a fourth pressure sensor 2-4 and a fifth thermocouple 3-5 located at the outlet of the preheating section 9. The inlet and outlet pressure and temperature differences of each steam generator simulator's primary side are monitored by pressure and temperature sensors located at the inlet and outlet of each simulator. When the thermal power of the preheating section 9 and the cold power of the power steam generator reach equilibrium, the frequency of the shielded pump 8 is gradually reduced until it stops. The water circulation is maintained by the density difference formed by the height difference between the preheating section 9 and the steam generator simulator. The natural circulation flow rate is monitored by the first liquid mass flow meter 10-1 installed on the main pipeline of the primary loop system, the flow distribution of each branch is monitored by the flow meter installed on the primary side branch of each steam generator simulator, and the pressure change on the secondary side is monitored by the pressure sensor installed inside the secondary side of each steam generator simulator to confirm that the natural circulation is stably established.

[0048] S20: Configure at least one steam generator simulator as a cooling steam generator and the rest as power steam generators, and open the discharge valve of the cooling steam generator to release pressure.

[0049] Specifically, the first steam generator simulator 1-1 and the second steam generator simulator 1-2 are configured as power steam generators, and the third steam generator simulator 1-3 is configured as a cooling steam generator. The first discharge valve 15-1 on the secondary side of the first steam generator simulator 1-1 and the second discharge valve 15-2 on the secondary side of the second steam generator simulator 1-2 are closed, and the third discharge valve 15-3 on the secondary side of the third steam generator simulator 1-3 is opened to release pressure, so that the pressure on the secondary side of the cooling steam generator drops to near atmospheric pressure, establishing a low-pressure side. Simultaneously, the sixteenth regulating valve 7-16 and the seventeenth regulating valve 7-17 on the secondary side outlet steam pipe of the first steam generator simulator 1-1 are closed; the eighteenth regulating valve 7-18 and the nineteenth regulating valve 7-19 on the secondary side outlet steam pipe of the second steam generator simulator 1-2 are closed; and the twentieth regulating valve 7-20 and the twenty-first regulating valve 7-21 on the secondary side outlet steam pipe of the third steam generator simulator 1-3 are closed, so that the steam generated by the power steam generator is temporarily not output, and the steam generated by the cooling steam generator is discharged through the third exhaust valve 15-3. The pressure change on the secondary side is monitored by the seventeenth pressure sensor 2-17 installed inside the secondary side of the third steam generator simulator 1-3 to confirm that the pressure relief is complete.

[0050] S30: Feedwater is injected into the secondary side of the power steam generator through the secondary loop system. The high-temperature and high-pressure water flowing through the primary side of the power steam generator heats the feedwater, causing it to vaporize and generate high-pressure steam.

[0051] Specifically, water is supplied to the deaerator 18 through the second pressurized water tank 6-2, and the heating rods inside the deaerator 18 are activated to heat the water inside the deaerator 18 to a saturated state. The internal pressure, feedwater pressure, and temperature of the deaerator are monitored by the fourteenth pressure sensor 2-14 installed inside the deaerator 18, the eighth pressure sensor 2-8 installed on the feedwater pipe at the outlet of the deaerator 18, and the ninth thermocouple 3-9 to confirm that the deaerator has reached a saturated state. Then, the twenty-fourth regulating valve 7-24 is opened to control the total flow rate of the feedwater at the outlet of the deaerator 18. At the same time, at least one of the tenth regulating valve 7-10 and the eleventh regulating valve 7-11 on the secondary side inlet branch pipe of the first steam generator simulator 1-1, and at least one of the twelfth regulating valve 7-12 and the thirteenth regulating valve 7-13 on the secondary side inlet branch pipe of the second steam generator simulator 1-2, are opened to inject the preset feedwater volume into the secondary side of the power steam generator through the secondary loop system. The injection feedwater flow rate is then monitored by the fifth liquid mass flow meter 10-5 located on the secondary side inlet branch pipe of the first steam generator simulator 1-1 and the sixth liquid mass flow meter 10-6 located on the secondary side inlet branch pipe of the second steam generator simulator 1-2. Once the preset feedwater volume is reached, the aforementioned regulating valve is closed. The high-temperature, high-pressure water flowing through the primary side of the first steam generator simulator 1-1 and the second steam generator simulator 1-2 heats the secondary side feedwater through a U-tube, causing the feedwater to vaporize and generate high-pressure steam. Finally, the internal pressure of the secondary side is monitored by the fifteenth pressure sensor 2-15 located inside the secondary side of the first steam generator simulator 1-1 and the sixteenth pressure sensor 2-16 located inside the secondary side of the second steam generator simulator 1-2. When the pressure rises to a preset value (e.g., 1.5 MPa ~ 2.0 MPa), the generation of high-pressure steam is confirmed to be complete.

[0052] S40: Through the secondary loop system, the high-pressure steam generated by the power steam generator is introduced into the deaerator through the steam pipeline, increasing the internal pressure of the deaerator and driving the feedwater in the deaerator to be injected into the secondary side of the cooling steam generator through the feedwater pipeline.

[0053] Specifically, at least one of the sixteenth regulating valve 7-16 and the seventeenth regulating valve 7-17 on the secondary side outlet steam pipe of the first steam generator simulator 1-1, and at least one of the eighteenth regulating valve 7-18 and the nineteenth regulating valve 7-19 on the secondary side outlet steam pipe of the second steam generator simulator 1-2, is opened to allow the high-pressure steam generated by the power steam generator to merge into the main steam pipe via the first steam pipe and the second steam pipe. The twenty-second regulating valve 7-22 on the main steam pipe is then opened, and the high-pressure steam is reduced to a preset pressure (e.g., 0.8MPa~1.0MPa) via the pressure reducing valve 17. The pressure before and after the pressure reducing valve 17 is monitored by the twelfth pressure sensor 2-12 located before the pressure reducing valve 17 and the thirteenth pressure sensor 2-13 located after the pressure reducing valve 17, and the pressure reducing valve 17 is adjusted to stabilize the outlet pressure. After opening the pressure reducing valve 17, the twenty-third regulating valve 7-23 is used to introduce the pressure-reduced high-pressure steam into the pressurization port of the deaerator 18 through the main steam pipeline (either upper gas-side pressurization or lower water-side pressurization can be selected), increasing the internal pressure of the deaerator 18. The fourteenth pressure sensor 2-14 installed inside the deaerator 18 monitors the increase in internal pressure. When the internal pressure of the deaerator rises above the secondary side pressure of the cooling steam generator, the fourteenth regulating valve 7-14 and the fifteenth regulating valve 7-15 on the secondary side inlet branch pipe of the third steam generator simulator 1-3 are opened, driving the saturated feedwater in the deaerator 18 to be injected into the secondary side of the third steam generator simulator 1-3 through the feedwater pipeline and the third one-way check valve 20-3. The injection feedwater flow rate is monitored by the seventh liquid mass flow meter 10-7 installed on the secondary side inlet branch pipe of the third steam generator simulator 1-3, and the internal pressure change on the secondary side is monitored by the seventeenth pressure sensor 2-17 installed inside the secondary side of the third steam generator simulator 1-3.

[0054] S50: The measurement system collects data in real time to observe and record the cooling process of the primary loop system, the steam generation and driving process of the power steam generator, and the cyclic pulse process of secondary side feedwater injection, interruption, and injection of the cooling steam generator.

[0055] The data collected by the measurement system includes: pressure, temperature, and flow rate of the primary loop system; pressure, temperature, and flow rate of the primary side of each steam generator simulator; pressure, temperature, and flow rate of the secondary loop system; pressure and temperature of the secondary side of each steam generator simulator; temperature of the pipe wall of each steam generator simulator; and pressure before and after the pressure reducing valve on the steam pipeline. See the section on specific connection locations of the measurement system in Example 1.

[0056] Specifically: The cooling process of the primary loop system: The temperature change of the primary loop is monitored by the fourth pressure sensor 2-4 and the fifth thermocouple 3-5 installed at the outlet of the preheating section 9; the circulation flow is monitored by the first liquid mass flow meter 10-1 installed on the main pipeline of the primary loop system; and the pressure difference and temperature difference at the inlet and outlet of each branch are monitored by the pressure sensors and temperature sensors installed at the inlet and outlet of the primary side of each steam generator simulator. The cooling rate and heat removal of the primary loop system are calculated.

[0057] Steam generation and driving process of the power steam generator: The pressure changes inside the secondary side are monitored by the fifteenth pressure sensor 2-15 inside the secondary side of the first steam generator simulator 1-1 and the sixteenth pressure sensor 2-16 inside the secondary side of the second steam generator simulator 1-2. The steam generation pressure and flow rate are monitored by the ninth pressure sensor 2-9 and the first gas mass flow meter 16-1 on the first steam pipeline, the tenth pressure sensor 2-10 and the second gas mass flow meter 16-2 on the second steam pipeline. The adjustment of the driving steam is monitored by the twelfth pressure sensor 2-12 before the pressure reducing valve 17 and the thirteenth pressure sensor 2-13 after the pressure reducing valve 17.

[0058] The cyclic pulse process of feedwater injection, interruption, and injection on the secondary side of the cooling steam generator: The feedwater injection flow rate is monitored by the seventh liquid mass flow meter 10-7, which is installed on the secondary side inlet branch pipe of the third steam generator simulator 1-3. When feedwater is injected, the flow meter displays a positive value. The injected feedwater is heated and vaporized by the high-temperature and high-pressure water in the primary loop, causing the internal pressure on the secondary side of the third steam generator simulator 1-3 to rise. The pressure rise is monitored by the seventeenth pressure sensor 2-17 installed inside. When the pressure rises to a certain level, feedwater injection is blocked, and the flow rate displayed by the seventh liquid mass flow meter 10-7 drops to zero or close to zero. At the same time, the third discharge valve 15-3 continuously releases pressure, and the secondary side pressure gradually decreases. When the pressure drops below the deaerator pressure, feedwater injection resumes, and the seventh liquid mass flow meter 10-7 displays the flow rate again, forming a cyclic pulse process of feedwater injection, interruption, and injection. Simultaneously, the pressure and flow rate of the discharged steam are monitored by the eleventh pressure sensor 2-11 and the third gas mass flow meter 16-3 installed on the third steam pipeline, and the temperature change of the tube wall is monitored by the twelfth thermocouple 3-12 installed at the contact position between the U-shaped tube and the tube sheet of the third steam generator simulator 1-3, to evaluate the heat transfer effect. The frequency, amplitude, and duration of the above-mentioned cyclic pulse process are observed and recorded until the primary loop system cools down to the preset safe temperature or the deaerator feedwater is exhausted, at which point the pulse process ends.

[0059] By implementing this invention, the following beneficial effects are achieved: This invention provides a system for verifying the passive pulse cooling process of a nuclear power plant throughout the entire process. It provides high-temperature, high-pressure water through the primary loop system to simulate the core thermal conditions under accident scenarios. At least three steam generator simulators are used, with at least one configured as a cooling steam generator and the rest as power steam generators. This accurately simulates the steam output of the power steam generators, the cooling effect of the cooling steam generators, and the interaction feedback between them, realistically reflecting the prototype parameters. A passively driven feedwater transmission path is established through the deaerator, feedwater pipeline, and steam pipeline of the secondary loop system. Pressure, temperature, and flow data of the entire system are collected by a measurement system to verify the passive pulse cooling process of the entire nuclear power plant. This invention uses a primary loop system to divert water to multiple steam generator simulators, replacing multiple loops in the prototype nuclear power plant, saving experimental costs and reducing experimental complexity. It can be used as an engineering experimental device to directly verify the feasibility of the passive pulse cooling method in nuclear power plants, providing methodological feasibility support for the retrofitting and operation of existing Generation II nuclear power plants.

[0060] The present invention verifies the passive pulse cooling method for the entire nuclear power plant process. It establishes a high-temperature, high-pressure water circulation in the primary loop system, bringing the primary side of each steam generator simulator to a preset temperature and pressure to simulate the core thermal conditions under accident conditions. At least one steam generator simulator is configured as a cooling steam generator, and the rest as power steam generators. The exhaust valve of the cooling steam generator is opened to release pressure, establishing the pressure differential required for drive. Feedwater is injected into the secondary side of the power steam generators through the secondary loop system. The high-temperature, high-pressure water flowing through the primary side of the power steam generator heats the feedwater, causing it to vaporize and generate high-pressure steam, converting the heat from the primary loop into passive driving force. The high-pressure steam generated by the power steam generator is introduced into the deaerator, increasing the internal pressure and driving the feedwater in the deaerator to inject into the secondary side of the cooling steam generator, achieving passive feedwater control. Data is collected in real time through a measurement system to observe and record the cooling process of the primary loop system, the steam generation and driving process of the power steam generator, and the cyclic pulse process of feedwater injection, interruption, and injection into the secondary side of the cooling steam generator. This method fully reproduces the cyclic pulse process of feedwater injection, interruption, and injection. The key data collected by the measurement system can directly verify the reliability of the passive pulse cooling method, providing experimental support for the improvement of the SOP procedures of existing second-generation nuclear power plants.

[0061] It is understood that the above embodiments only illustrate preferred embodiments of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that for those skilled in the art, the above embodiments or technical features can be freely combined, and several modifications and improvements can be made without departing from the concept of the present invention. These all fall within the protection scope of the present invention. That is, the embodiments described "in some embodiments" can be freely combined with any of the embodiments above and below. Therefore, all equivalent transformations and modifications made within the scope of the claims of the present invention should fall within the scope of the claims of the present invention.

Claims

1. A system for verifying passive pulse cooling throughout the entire nuclear power process, characterized in that, include: The primary loop system is used to provide high-temperature, high-pressure water; At least three steam generator simulators, each of which has its primary side connected to the primary loop system and its secondary side equipped with a discharge valve and a steam pipe; The secondary loop system includes a deaerator, the outlet of which is connected to the secondary side of each steam generator simulator via a water supply pipe, and the steam pipe is connected to the secondary side of the steam generator simulator and the pressurization port of the deaerator. At least one of the steam generator simulators is configured as a cooling steam generator, and the rest are configured as power steam generators. The high-pressure steam generated on the secondary side of the power steam generator enters the deaerator through the steam pipe, driving the feedwater in the deaerator to be injected into the secondary side of the cooling steam generator. The injected feedwater is heated and vaporized, causing the secondary side pressure to rise. Together with the continuous pressure relief of the discharge valve, a cyclic pulse process of feedwater injection, interruption, and injection is formed. The measurement system is used to collect pressure, temperature, and flow data of the system used to verify the passive pulse cooling process of the entire nuclear power plant.

2. The system for verifying passive pulse cooling of the entire nuclear power plant process according to claim 1, characterized in that, The primary loop system is a closed loop, comprising a first pressurized water tank, a shielded pump, a throttling orifice plate, a preheating section, a primary side branch of each steam generator simulator, and a condenser connected in sequence, with the outlet of the condenser connected to the inlet of the first pressurized water tank; The cooling side of the condenser is connected to a cooling system for cooling the high-temperature, high-pressure water of the primary loop system during non-pulse phases to maintain the stability of the experimental conditions.

3. The system for verifying passive pulse cooling of the entire nuclear power process according to claim 1, characterized in that, In the dual-loop system, the water supply pipeline is equipped with a one-way check valve to prevent steam backflow and ensure the one-way nature of the passive drive path; the steam pipeline is equipped with a pressure reducing valve to regulate the steam pressure to match the verification operating conditions.

4. The system for verifying passive pulse cooling of the entire nuclear power plant process according to claim 1, characterized in that, The secondary loop system also includes a second pressurized water tank for supplying water to the deaerator; the deaerator is equipped with a heating rod to heat the water to saturation; the pressurization port of the deaerator is located at the upper end of the deaerator to achieve gas-side pressurization, or at the lower end of the deaerator to achieve water-side pressurization.

5. A system for verifying passive pulse cooling of the entire nuclear power process according to claim 2, characterized in that, All of the steam generator simulators are positioned at the same horizontal level and at the highest point in the closed loop of the primary loop system, while the preheating section is located at the lowest point in the closed loop of the primary loop system, in order to establish the height difference required for natural circulation and to verify the natural circulation cooling effect under the condition of power failure throughout the plant.

6. A system for verifying passive pulse cooling of the entire nuclear power plant process according to any one of claims 1 to 5, characterized in that, The steam generator simulator is equipped with a U-shaped tube made of stainless steel or Inconel material; the opening degree of the discharge valve is adjustable to simulate the opening state of different numbers of bypass atmospheric discharge valves in a nuclear power plant.

7. A system for verifying passive pulse cooling of the entire nuclear power process according to claim 3, characterized in that, The measurement system includes: Pressure measurement unit, temperature measurement unit and flow measurement unit are installed in the primary loop system; Pressure measurement unit, temperature measurement unit and flow measurement unit are installed on the primary side of each of the steam generator simulators; Pressure measurement unit, temperature measurement unit and flow measurement unit are installed in the dual-loop system; Pressure and temperature measurement units are installed on the secondary side of each of the steam generator simulators; Temperature measurement units are installed on the pipe walls of each of the steam generator simulators; The pressure measuring unit before and after the pressure reducing valve.

8. A method for verifying passive pulse cooling throughout the entire nuclear power process, characterized in that, The system for verifying passive pulse cooling of the entire nuclear power plant process according to any one of claims 1 to 7 includes the following steps: S10: A high-temperature and high-pressure water circulation is established through a primary loop system, so that the primary side of each of the steam generator simulation components reaches the preset temperature and pressure; S20: Configure at least one of the steam generator simulators as a cooling steam generator and the rest as power steam generators, and open the discharge valve of the cooling steam generator to release pressure; S30: Feedwater is injected into the secondary side of the power steam generator through the secondary loop system, and the feedwater is heated by the high temperature and high pressure water flowing through the primary side of the power steam generator, so that the feedwater is vaporized to generate high pressure steam. S40: Through the secondary loop system, the high-pressure steam generated by the power steam generator is introduced into the deaerator through the steam pipeline, increasing the internal pressure of the deaerator and driving the feedwater in the deaerator to be injected into the secondary side of the cooling steam generator through the feedwater pipeline. S50: The measurement system collects pressure, temperature and flow data in real time, observes and records the cooling process of the primary loop system, the steam generation and driving process of the power steam generator, and the cyclic pulse process of secondary side water injection, interruption and injection of the cooling steam generator.

9. The method for verifying passive pulse cooling of the entire nuclear power plant process according to claim 8, characterized in that, In step S10, the high-temperature and high-pressure water circulation is established by either forced circulation or natural circulation. The forced circulation is to start the shielded pump of the primary loop system to drive water circulation; The natural circulation involves creating a height difference between the preheating section of the primary loop system and the steam generator simulator, with the preheating section at a low position and the steam generator simulator at a high position. Cooling is provided to the secondary side of the steam generator simulator by the secondary loop system. Once the water temperature of the primary loop system reaches a predetermined temperature, the shielded pump is stopped, and circulation is maintained by density difference.

10. The method for verifying passive pulse cooling of the entire nuclear power plant process according to claim 8, characterized in that, The data collected by the measurement system in step S50 includes: The pressure, temperature, and flow rate of the primary loop system; Pressure, temperature, and flow rate on the primary side of each of the aforementioned steam generator simulators; The pressure, temperature, and flow rate of the dual-loop system; Pressure and temperature on the secondary side of each of the steam generator simulators; The temperature of the pipe wall of each of the steam generator simulators; The pressure before and after the pressure reducing valve on the steam pipeline.

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