A miniaturized test system for fuel rod in pile testing

Abstract

The application relates to the technical field of nuclear fuel in-pile testing, in particular to a miniaturized test system for fuel rod in-pile testing, which comprises an in-pile test device, a primary water circulation system, a water quality adjusting system, a gas supply system and an emergency water injection system; the primary water circulation system is connected with the in-pile test device; the water quality adjusting system is connected with the primary water circulation system to adjust the chemical parameters of water in the primary water circulation system to expected values; the gas supply system is connected with the in-pile test device to introduce a heat insulation medium into the in-pile test device; and the emergency water injection system is connected with the in-pile test device to introduce cooling water into the in-pile test device. On the basis of meeting the indexes of temperature, pressure, water chemical environment parameters, flow rate and the like of nuclear fuel, the application can reduce system complexity and construction cost and improve the in-pile testing capacity of nuclear fuel.

Description

Technical Field

[0001] This application relates to the field of nuclear fuel in-reactor testing technology, and more specifically to a miniaturized test system for in-reactor testing of fuel rods. Background Technology

[0002] During the development of nuclear fuel, its comprehensive performance must be verified through in-reactor testing to support safety assessments and design finalization. Current technologies employ two methods: in-reactor testing and loop testing. In-reactor testing is easy to implement, but it can only simulate the neutron flux and temperature parameters of nuclear fuel, failing to simulate pressure, water chemistry parameters, flow rate, and other parameters, thus lacking representativeness and being used only for exploratory scientific research. Loop testing can achieve these parameters, but test loop resources are scarce, and test loop systems are complex, costly to construct, and difficult to operate and maintain. Therefore, limitations in existing in-reactor testing capabilities prevent large-scale in-reactor testing of nuclear fuel, hindering the development process. Summary of the Invention

[0003] This application addresses at least one of the technical problems mentioned in the background art by providing a miniaturized test system for in-reactor testing of fuel rods. While meeting the requirements for nuclear fuel temperature, pressure, water chemistry environmental parameters, flow rate, and other indicators, it reduces system complexity and construction costs, and improves the in-reactor testing capability of nuclear fuel.

[0004] This application is achieved through the following technical solution:

[0005] A miniaturized test system for in-reactor testing of fuel rods includes:

[0006] In-core testing apparatus;

[0007] A primary water circulation system, which is connected to the in-pile test apparatus;

[0008] A water quality conditioning system, which is connected to the primary water circulation system to adjust the chemical parameters of the water in the primary water circulation system to a desired value;

[0009] A gas supply system, which is connected to the in-pile test apparatus to supply an insulating medium to the in-pile test apparatus;

[0010] An emergency water injection system is connected to the in-pile test apparatus to supply cooling water to the in-pile test apparatus.

[0011] In some optional embodiments, the in-pile testing apparatus includes:

[0012] A central component, which is connected to the primary water circulation system and the emergency water injection system;

[0013] A connecting section is sleeved on the central component and one end of the connecting section is connected to the flange of the central component. A first through-air pipe and a second through-air pipe communicating with the interior of the connecting section are connected to the connecting section.

[0014] An isolation tube, which is sleeved on the central assembly and connected to the flange at the other end of the connecting section;

[0015] The port of the first penetrating trachea within the connecting segment is located at a position flush with the end of the central component away from the connecting segment.

[0016] In some alternative embodiments, the central component includes:

[0017] The test section has upper and lower supports arranged at intervals;

[0018] A fuel rod, one end of which engages with the lower support, and the other end of which engages with the upper support via a spring.

[0019] In some alternative embodiments, the primary water circulation system includes:

[0020] A heat exchanger connected to the in-pile test apparatus to supply primary water to the in-pile test apparatus or to receive primary water from the in-pile test apparatus.

[0021] A cooler connected to the heat exchanger;

[0022] A first filter is connected to the cooler;

[0023] A sealed water tank, which is connected to the first filter and also to the heat exchanger.

[0024] In some alternative embodiments, an ion exchange module is connected between the first filter and the sealed water tank.

[0025] In some alternative embodiments, a heater is connected between the heat exchanger and the in-pile test apparatus to heat the primary water discharged from the heat exchanger.

[0026] In some alternative embodiments, a fuel breakage monitoring unit is connected between the cooler and the first filter.

[0027] In some optional embodiments, the water quality conditioning system includes:

[0028] A reagent dispensing module, wherein the reagent dispensing module is connected to the primary water circulation system;

[0029] A gas injection module, which is connected to the primary water circulation system;

[0030] A water quality monitoring unit is used to monitor primary water in a primary water circulation system. The water quality monitoring unit includes one or more of the following modules: pH detection module, conductivity detection module, calcium ion concentration detection module, magnesium ion concentration detection module, silicon ion concentration detection module, sodium ion concentration detection module, potassium ion concentration detection module, lithium ion concentration detection module, and boron ion concentration detection module.

[0031] In some alternative embodiments, the gas supply system includes:

[0032] High-pressure gas cylinders;

[0033] A low-pressure gas storage tank, which is connected between the high-pressure gas cylinder and the in-pile test device;

[0034] The exhaust gas tank is connected to the in-pile test device.

[0035] In some alternative embodiments, the emergency water injection system includes an emergency water injection tank connected to the in-pile test apparatus via two parallel shut-off valve assemblies.

[0036] Compared with the prior art, this application has the following advantages and beneficial effects:

[0037] 1. The miniaturized test system for in-reactor testing of fuel rods provided in this application allows the outer diameter of the in-reactor test device to be controlled within 60 mm, enabling tests to be conducted in any irradiation channel, thus improving the flexibility of the test and expanding its application scope.

[0038] 2. The miniaturized test system for fuel rod reactor testing provided in this application, through the setting of a primary water circulation system, can utilize the pressure difference between the high pressure in the main pipeline and the low pressure in the sealed water tank for filtration and ion exchange, eliminating the need for an additional charging pump and simplifying equipment configuration; the heat exchanger in the primary water circulation system can achieve heat exchange by heating the inlet water and cooling the outlet water, maximizing the utilization of the system's own thermal energy, and further supplemented by coolant and heaters for adjustment, reducing the system's consumption of external energy and saving energy and operating costs.

[0039] 3. The miniaturized test system for in-reactor testing of fuel rods provided in this application can supply heat insulation medium to the in-reactor test device through the setting of the gas supply system, thereby achieving heat insulation between high-temperature components and low-temperature components. At the same time, the parameters of the heat insulation medium are easy to detect, thereby facilitating the determination of whether the pressure boundary has been damaged, and ensuring the safety of the research reactor and fuel rods. Attached Figure Description

[0040] To more clearly illustrate the technical solutions of the exemplary embodiments of this application, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this application and should not be considered as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort. In the drawings:

[0041] Figure 1 A schematic diagram of a miniaturized test system for in-reactor testing of fuel rods provided in an embodiment of this application;

[0042] Figure 2 This is a schematic diagram of the in-pile testing device provided in an embodiment of this application;

[0043] Figure 3 This is a schematic diagram of a fuel damage monitoring system provided in an embodiment of this application.

[0044] The attached diagram shows the markings and corresponding component names:

[0045] 1-1. In-core test apparatus; 1-2. Heat exchanger; 1-3. Cooler; 1-4. Fuel damage monitoring unit; 1-5. First filter; 1-6. Main pipeline check valve; 1-7. Electric valve; 1-8. First ion exchange column; 1-9. Shut-off valve; 1-10. Electric valve; 1-11. Second ion exchange column; 1-12. Shut-off valve; 1-13. Electric valve; 1-14. Third ion exchange column; 1-15. Shut-off valve; 1-16. Second filter; 1-17. First electric shut-off valve; 1-18. Second electric shut-off valve; 1-19. Third electric shut-off valve; 1-20. Fourth electric shut-off valve; 1-21. First pressure reducing valve; 1-22. Second pressure reducing valve; 1-23. Sealed water tank; 1-24. Shut-off valve; 1-25. First booster pump; 1-26. Check valve; 1-27. Shut-off valve; 1-28. Second booster pump; 1-29. Check valve; 1-30. Pressure stabilizing tank; 1-31. Flow meter; 1-32. Flow regulating valve; 1-33. Heater; 1-34. Outlet flange; 1-35. Inlet flange;

[0046] 1-1-1 Outlet flange; 1-1-2 Inlet flange; 1-1-3 Emergency water inlet; 1-1-4 First penetrating air pipe; 1-1-5 Second penetrating air pipe; 1-1-6 Isolation pipe; 1-1-7 Connecting section; 1-1-8, Test Section; 1-1-9, Inlet Pipe; 1-1-10, Outlet Pipe; 1-1-11, First Instrument Tee; 1-1-12, Emergency Injection Pipe; 1-1-13, Top Cover; 1-1-14, Second Instrument Tee; 1-1-15, Second Temperature Measuring Instrument; 1-1-16, Second Pressure Measuring Instrument; 1-1-17, First Temperature Measuring Instrument; 1-1-18, First Pressure Measuring Instrument; 1-1-19, Neutron Flux Measuring Instrument; 1-1-20, Second Temperature Measuring Instrument Probe; 1-1-21, First Temperature Measuring Instrument Probe; 1-1-22, Neutron Flux Measuring Instrument Probe; 1-1-23, Upper Support; 1-1-24, Spring; 1-1-25, Lower Support; 1-1-26, Central Flow Channel; 1-1-27, Outer Annular Gap Flow Channel;

[0047] 1-2-1, Hot end inlet of heat exchanger; 1-2-2, Hot end outlet of heat exchanger; 1-2-3, Cold end inlet of heat exchanger; 1-2-4, Cold end inlet of heat exchanger;

[0048] 1-4-1 Gamma Detection Device; 1-4-2 Delayed Neutron Detection Device; 1-4-3 Nuclide Monitoring Device; 1-4-4 First Electric Valve of Fuel Damage Monitoring Unit; 1-4-5 Second Electric Valve of Fuel Damage Monitoring Unit; 1-4-6 Third Electric Valve of Fuel Damage Monitoring Unit; 1-4-7 Fourth Electric Valve of Fuel Damage Monitoring Unit; 1-4-8 Fifth Electric Valve of Fuel Damage Monitoring Unit; 1-4-9 Sixth Electric Valve of Fuel Damage Monitoring Unit; 1-4-10 Seventh Electric Valve of Fuel Damage Monitoring Unit;

[0049] 1-23-1, First takeover; 1-23-2, Second takeover; 1-23-3, Third takeover; 1-23-4, Fourth takeover; 1-23-5, Fifth takeover; 1-23-6, Sixth takeover;

[0050] 2-1, First isolation valve; 2-2, Second isolation valve; 2-3, Water quality monitoring unit; 2-4, Peristaltic pump; 2-5, Peristaltic pump check valve; 2-6, Third isolation valve; 2-7, Fourth isolation valve; 2-8, First metering pump check valve; 2-9, First metering pump; 2-10, First solvent tank; 2-11, Second metering pump check valve; 2-12, Second metering pump; 2-13, Second solvent tank; 2-14, Fifth isolation valve; 2-15, Sixth isolation valve; 2-16, High-pressure gas cylinder; 2-17, Gas storage tank inlet electric valve; 2-18, Low-pressure gas storage tank; 2-19, First gas pressure monitoring gauge; 2-20, First safety valve; 2-21, Seventh isolation valve; 2-22, Eighth isolation valve;

[0051] 3-1. High-pressure inert gas cylinder; 3-2. Electric inlet valve for inert gas storage tank; 3-3. Inert gas storage tank; 3-4. Second gas pressure monitoring gauge; 3-5. Second safety valve; 3-6. Ninth isolation valve; 3-7. Tenth isolation valve; 3-8. Gas supply system pressure monitoring gauge; 3-9. Gas supply system temperature monitoring gauge; 3-10. Gas supply system humidity monitoring gauge; 3-11. Third safety valve; 3-12. Eleventh isolation valve; 3-13. Twelfth isolation valve; 3-14. Tail gas tank; 3-15. Third gas pressure monitoring gauge;

[0052] 4-1 Emergency water tank; 4-2 Fifth electric shut-off valve; 4-3 Sixth electric shut-off valve; 4-4 First solenoid valve; 4-5 Second solenoid valve; 4-6 Water tank level monitor. Detailed Implementation

[0053] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the embodiments and accompanying drawings. The illustrative embodiments and descriptions of this application are only for explaining this application and are not intended to limit this application.

[0054] This application provides a miniaturized test system for in-reactor testing of fuel rods, such as... Figures 1-3 As shown, the miniaturized test system for in-reactor testing of fuel rods includes an in-reactor test device 1-1, a primary water circulation system, a water quality conditioning system, a gas supply system, and an emergency water injection system; the entire system is designed with a pressure of 17.2 MPa, a temperature of 350°C, and a heat exchange power of no more than 100 kW.

[0055] The primary water circulation system, gas supply system, and emergency water injection system are connected to the in-core test device 1-1. The gas supply system mainly supplies the in-core test device with heat insulation medium, while the emergency water injection system supplies cooling water into the in-core test device 1-1.

[0056] In actual implementation, the inlet flange 1-1-2 of the in-core test device 1-1 is connected to the outlet flange 1-34 of the primary water circulation system, and the outlet flange 1-1-1 of the in-core test device 1-1 is connected to the inlet flange 1-35 of the primary water circulation system, forming a closed circulation loop. The heat released from the fuel rods in the in-core test device 1-1 is removed through the primary water circulation. The circulation method can be that the primary water first flows through the outer annular channel 1-1-27 of the in-core test device 1-1, then reverses at the bottom of the in-core test device 1-1 and enters the central channel 1-1-26 of the in-core test device 1-1. After being heated by the fuel rods in the central channel 1-1-26, it flows to the outlet of the in-core test device 1-1.

[0057] The water quality conditioning system is connected to the closed water tank 1-23 of the primary water circulation system. This system monitors the chemical parameters of the water in the closed water tank 1-23 and adjusts the water quality by adding appropriate chemical reagents and gases based on the monitoring results. Therefore, the water quality conditioning system can include a monitoring module and a conditioning module. The conditioning module controls the flow rate, volume, and pressure of the chemical reagents and gases based on the monitoring results. The inlet of the monitoring module in the water quality conditioning system is connected to the second connecting pipe 1-23-2 of the closed water tank 1-23 of the primary water circulation system, and the return outlet is connected to... The third connector 1-23-3 of the sealed water tank 1-23 in the secondary water circulation system is connected to form a circulation monitoring loop for continuous online monitoring of water chemical parameters. The water quality conditioning system includes a first reagent dispensing module, a second reagent dispensing module, and a gas dispensing module. The outlets of the first and second reagent dispensing modules are connected to the fourth connector 1-23-4 of the water tank in the primary water circulation system to form a liquid chemical reagent dispensing branch. The outlet of the gas dispensing module is connected to the fifth connector 1-23-5 of the water tank in the primary water circulation system to form a gas dispensing branch. The gas supply system includes a gas source branch and an exhaust branch. The gas source branch is connected to the first through-pipe 1-1-4 of the in-core test device, and the exhaust branch is connected to the second through-pipe 1-1-5 of the in-core test device. The emergency water injection system is connected to the emergency water injection port 1-1-3 of the in-pile test device 1-1. The water tank 4-1 of the emergency water injection system is located higher than the emergency water injection port 1-1-3, so the emergency water injection system can adopt gravity flow to reduce the need for safety pumps and high-pressure gas cylinders in traditional high-temperature and high-pressure circuits, thus optimizing the system setup.

[0058] In some optional embodiments, the in-core test apparatus 1-1 includes an isolation pipe 1-1-6, a connecting section 1-1-7, and a central assembly. In operation, the isolation pipe 1-1-6 is sealed to the top flange hole of the research reactor to ensure the integrity of the research reactor's pressure boundary, thus isolating the in-core test apparatus 1-1 from the research reactor. The lower flange of the connecting section 1-1-7 is sealed to the upper flange of the isolation pipe 1-1-6, and the upper flange of the connecting section 1-1-7 is sealed to the flange of the central assembly. The aforementioned sealing connection can be achieved, for example, by using a sealing ring to ensure good sealing performance inside the in-core test apparatus 1-1. The connecting section 1-1-7 has a first through hole and a second through hole, through which the first through gas pipe 1-1-4 passes. The first through-hole extends through the connecting section 1-1-7 to the bottom of the in-core test device 1-1, meaning that the port of the first through-hole gas pipe 1-1-4 in the in-core test device 1-1 is flush with the lower end of the central assembly. The second through-hole gas pipe 1-1-5 passes through the wall of the connecting section 1-1-7 through the second through-hole, thus forming an air intake and exhaust channel. This ensures that the pure gas supplied by the gas supply system can completely replace the existing gas inside the in-core test device 1-1. The central assembly may specifically include the test section 1-1-8, the water inlet pipe 1-1-9, the water outlet pipe 1-1-10, the emergency water injection pipe 1-1-12, the top cover 1-1-13, the first instrument tee 1-1-11, and the second instrument tee 1-1-1-1. 14. First temperature measuring instrument 1-1-17, second temperature measuring instrument 1-1-15, first pressure measuring instrument 1-1-18, second pressure measuring instrument 1-1-16, and neutron flux measuring instrument 1-1-19; Test section 1-1-8 is connected to the top cover 1-1-13 as a whole through inlet pipe 1-1-9, outlet pipe 1-1-10, and emergency water injection pipe 1-1-12, facilitating overall installation and disassembly; First instrument tee 1-1-11 and second instrument tee 1-1-14 are respectively connected to the top of inlet pipe 1-1-9 and outlet pipe 1-1-10 to form instrument lead wire channels; First temperature measuring instrument 1-1-17 is installed at the bottom inside inlet pipe 1-1-9, and the lead wire runs along the inlet pipe. The inner wall of 1-1-9 extends out from the first instrument tee 1-1-11. The second temperature measuring instrument 1-1-15 is installed at the bottom inside the water outlet pipe 1-1-10. The lead wire extends out from the second instrument tee 1-1-14 along the inner wall of the water outlet pipe. The pressure tap of the first pressure measuring instrument 1-1-18 is directly connected to the first instrument tee 1-1-11. The pressure tap of the second pressure measuring instrument 1-1-16 is directly connected to the second instrument tee 1-1-14. The neutron flux measuring instrument 1-1-19 is installed near the middle of the inner wall of the annular channel outside the in-core test device 1-1 to make the monitoring value more representative. The lead wire of the neutron flux measuring instrument 1-1-19 extends out from the first instrument tee 1-1-11 along the water inlet pipe.The fuel rods are positioned between the lower support 1-1-25 and the upper support 1-1-24 of test section 1-1-8. The fuel rods are connected to the upper support 1-1-24 by a spring 1-1-23, which presses the fuel rods firmly against the lower support 1-1-25, thus achieving fuel rod positioning and pre-tightening. The first temperature measuring instrument 1-1-17, the second temperature measuring instrument 1-1-15, the first pressure measuring instrument 1-1-18, the second pressure measuring instrument 1-1-16, and the neutron flux measuring instrument 1-1-19 of the central assembly respectively perform online measurement of temperature, pressure, and neutron flux. During the test, the fuel rods operate at high temperatures, causing the central assembly to also operate at high temperatures. A heat-insulating medium, typically an inert gas, is introduced into the gas supply system through the first through-gas pipe 1-1-4 to insulate the central assembly and prevent heat from being transferred from the isolation pipe to the reactor's cooling water, thus affecting the reactor's thermal characteristics.

[0059] Compared to traditional circuits, where the outer diameter of the in-core test device is over 100 mm, tests can only be conducted in a limited number of large-sized channels, thus limiting the application conditions of the tests. In contrast, the miniaturized test system for in-core testing of fuel rods provided in this application has miniaturized the in-core test device, allowing the outer diameter to be configured within 60 mm. This enables tests to be conducted in any irradiation channel, improving the flexibility of the tests and expanding the scope of applications.

[0060] In some optional embodiments, the primary water circulation system may specifically include an inlet flange 1-35, a heat exchanger 1-2, a cooler 1-3, a fuel damage monitoring unit 1-4, a first filter 1-5, a main pipeline check valve 1-6, a first ion exchange column module, a second ion exchange column module, a third ion exchange column module, a second filter 1-16, a first electric shut-off valve 1-17, a second electric shut-off valve 1-18, a third electric shut-off valve 1-19, a fourth electric shut-off valve 1-20, a first pressure reducing valve 1-21, a second pressure reducing valve 1-22, a sealed water tank 1-23, a first booster pump module, a second booster pump module, a flow regulating valve 1-32, a pressure stabilizing tank 1-30, a flow meter 1-31, and a heating element. Heat exchanger 1-2 is connected to the outlet flange 1-1-1 and inlet flange 1-1-2 of the in-pile test device 1-1 via inlet flange 1-35 and outlet flange 1-34, respectively. The outlet flange 1-34 is connected to heat exchanger 1-2 via heater 1-33 to heat the water flowing out of heat exchanger 1-2. Cooler 1-3 is connected to heat exchanger 1-2. Cooler 1-3, fuel damage detection unit 1-4, first filter 1-5, main pipeline check valve 1-6, first electric shut-off valve 1-17, third electric shut-off valve 1-19, and first pressure reducing valve 1-21 are connected in sequence. The first electric shut-off valve 1-17 is connected to the first ion exchange column module. The first, second, and third ion exchange column modules are connected in parallel. After being connected in parallel, these modules are connected to one end of the first electrically operated shut-off valve 1-17 via the second filter 1-16. The first electrically operated shut-off valve 1-17 and the second electrically operated shut-off valve 1-18 are connected in parallel to form the first parallel valve group. The third electrically operated shut-off valve 1-19 is connected in series with the first pressure reducing valve 1-21. The fourth electrically operated shut-off valve 1-20 is connected in series with the second pressure reducing valve 1-22. The series branch formed by the third electrically operated shut-off valve 1-19 and the first pressure reducing valve 1-21, and the series branch formed by the fourth electrically operated shut-off valve 1-20 and the second pressure reducing valve 1-22 are connected in parallel to form the second parallel valve group. The first parallel valve group and the second parallel valve group are connected in series. The reliability of the main pipeline flow path is ensured by the first parallel valve group and the second parallel valve group. Even if one valve fails to open normally, the other branch can still work normally. Moreover, the series connection between the first parallel valve group and the second parallel valve group ensures that there are two isolation valves on the high-pressure side and the low-pressure side of the main pipeline, ensuring the reliability of the pressure boundary. The first pressure reducing valve 1-21 is connected to the first connecting pipe 1-23-1 on the sealed water tank 1-23. The first booster pump module may include a shut-off valve 1-24, a first booster pump 1-25 and a check valve 1-26. The second booster pump module may include a shut-off valve 1-27, a second booster pump 1-28 and a check valve 1-29.The sixth connecting pipe 1-23-6 of the sealed water tank 1-23 is connected to the shut-off valve 1-24 and the shut-off valve 1-27 respectively. The shut-off valve 1-27 is connected to the second booster pump 1-28, the check valve 1-29 and the flow meter 1-31 in sequence and then connected to the cold end inlet 1-2-3 of the heat exchanger. The shut-off valve 1-24 is connected to the first booster pump 1-25, the check valve 1-26 and the flow meter 1-31 in sequence and then connected to the cold end inlet 1-2-3 of the heat exchanger. The outlet side of the check valves 1-26 and 1-29 is connected to the pressure stabilizing tank 1-30. One end of the outlet flange 1-34 is connected to the inlet flange 1-1-2 of the in-core test device 1-1, and the other end is connected to the hot end inlet 1-2-1 of the heat exchanger. After primary water undergoes first-stage cooling in the heat exchanger 1-2, it is discharged from the hot end outlet 1-2-2 and then enters the cooler 1-3 for second-stage cooling. After the temperature is reduced to the target temperature by adjusting the secondary cooling water flow rate of the cooler 1-3, fuel damage monitoring is performed in the fuel damage monitoring unit 1-4. Then, it is sent to the first filter 1-5 for filtration to remove suspended solids and solid impurities. Depending on the water quality, if it is necessary to add an ion exchange column module, the first electric shut-off valve 1-17 and the second electric shut-off valve 1-18 are closed, and one or more of the first, second, and third ion exchange column modules are opened. After the ion exchange column module is added, it returns to the main pipeline through the second filter 1-16. If no addition is required... The water entering the ion exchange column module is discharged directly through the first electric shut-off valve 1-17 and the second electric shut-off valve 1-18, then through the third electric shut-off valve 1-19, the fourth electric shut-off valve 1-20, the first pressure reducing valve 1-21, and the second pressure reducing valve 1-22 into the sealed water tank 1-23. The water quality adjustment system adds reagents or injects gas according to monitoring results to adjust the water quality parameters in the sealed water tank 1-23 to meet the requirements of the test water quality indicators. Then, the water in the sealed water tank 1-23 is sent to the cold end inlet 1-2-3 of the heat exchanger at a specific flow rate through the first booster pump module / second booster pump module. After the first stage of heating in the heat exchanger 1-2, the water is discharged from the cold end outlet 1-2-4 and enters the heater 1-33 for a second heating. After adjusting the power of the heater 1-33 to reach the test temperature, the water enters the in-pile test device 1-1 through the outlet flange 1-34.

[0061] In this embodiment, the system achieves control of test pressure, flow rate, temperature, and other indicators; it organically combines the functions of the main cooling system, purification system, and breaking and probing system of the traditional high-temperature and high-pressure loop, simplifying the system workflow and reducing system complexity; it fully utilizes the pressure difference from the high pressure in the main pipeline to the low pressure in the sealed water tank for filtration and ion exchange, eliminating the need for an additional charging pump and simplifying equipment configuration; and it uses heat exchanger 1-2 to perform the first heat exchange by heating the inlet water and cooling the outlet water, maximizing the utilization of the system's own thermal energy, supplemented by coolant and heater 1-33 for further adjustment, reducing the system's consumption of external energy and saving energy and operating costs.

[0062] In some optional embodiments, the fuel damage monitoring unit may specifically include one or more of the following: gamma detection device 1-4-1, delayed neutron detection device 1-4-2, and nuclide monitoring device 1-4-3. When the outlet water temperature of the cooler 1-3 exceeds the operating temperature range of the fuel damage monitoring unit, the first electric valve 1-4-4 of the fuel damage monitoring unit is opened, and the second electric valve 1-4-5, the third electric valve 1-4-6, the fourth electric valve 1-4-7, the fifth electric valve 1-4-8, the sixth electric valve 1-4-9, and the seventh electric valve 1-4-10 of the fuel damage monitoring unit are closed; when ... seventh electric valve 1-4-10 of the fuel damage monitoring unit is closed. When the outlet water temperature meets the operating temperature range of the fuel damage monitoring unit, the first electric valve 1-4-4 of the fuel damage monitoring unit is closed, and the second, third, fourth, fifth, sixth, and seventh electric valves 1-4-5, 1-4-6, 1-4-7, 1-4-8, 1-4-9, and 1-4-10 of the fuel damage monitoring unit are opened to introduce primary water into each monitoring unit. This fuel damage monitoring unit employs a combination of methods to achieve fuel damage monitoring, improving the diversity of monitoring and ensuring the reliability of monitoring results.

[0063] In some optional embodiments, the first ion exchange column module may specifically include electric valve 1-7, first ion exchange column 1-8, and shut-off valve 1-9; the second ion exchange column module may specifically include electric valve 1-10, second ion exchange column 1-11, and shut-off valve 1-12; and the third ion exchange column module may specifically include electric valve 1-13, third ion exchange column 1-14, and shut-off valve 1-15. The activation method is to close the first electric shut-off valve 1-17 and the second electric shut-off valve 1-18 on the main pipeline, and open electric valves 1-7, 1-10, and 1-13. Electric valves 1-7, 1-10, and 1-13 have a temperature interlock protection function; when the cooler outlet water temperature exceeds the temperature range of the first ion exchange column 1-8, the second ion exchange column 1-11, and the third ion exchange column 1-14, electric valves 1-7, 1-10, and 1-13 are not allowed to open. The exchange resins in the first ion exchange column 1-8, the second ion exchange column 1-11, and the third ion exchange column 1-14 can be anion exchange resins, cation exchange resins, or mixed ion exchange resins.

[0064] In some optional embodiments, the first booster pump 1-25 and the second booster pump 1-28 are naturally cooled plunger pumps. The two plunger pumps are powered by two different low-voltage power supplies, and both are connected to a UPS for reliable operation, with one pump in use and the other as a backup. A flow meter 1-31 is connected to the pump outlet. The flow rate entering the heat exchanger 1-2 can be controlled by the flow regulating valve 1-32 on the pump outlet return pipeline. Excess flow from the pump outlet returns to the sealed water tank through either the first pressure reducing valve 1-21 or the second pressure reducing valve 1-22. Compared to traditional high-temperature, high-pressure loop main pumps, naturally cooled plunger pumps do not require an additional main pump cooling water source, simplifying system setup. Furthermore, the excess flow from the pump returns to the sealed water tank 1-23 using the system's pressure reducing valves, eliminating the need for a dedicated return pipeline and further simplifying the system.

[0065] The water quality conditioning system is used for online monitoring and conditioning of the water quality in the sealed water tanks 1-23 to achieve the required water quality parameters for the experiment. In some optional embodiments, the monitoring module of the water quality conditioning system may specifically include a first isolation valve 2-1, a second isolation valve 2-2, a water quality monitoring unit 2-3, a peristaltic pump 2-4, a peristaltic pump check valve 2-5, a third isolation valve 2-6, and a fourth isolation valve 2-7; the water quality monitoring unit 2-3 may further include a pH monitoring module, a conductivity monitoring module, a calcium ion concentration monitoring module, a magnesium ion concentration monitoring module, a silicon ion concentration monitoring module, a sodium ion concentration monitoring module, a potassium ion concentration monitoring module, and a lithium ion concentration monitoring module. One or more measuring instruments from the concentration monitoring module and the boron ion concentration monitoring module are connected in sequence to the second connecting pipe 1-23-2 on the sealed water tank 1-23, which is then connected to the first isolation valve 2-1, the second isolation valve 2-2, the water quality monitoring unit 2-3, the peristaltic pump 2-4, the peristaltic pump check valve 2-5, the third isolation valve 2-6, and the fourth isolation valve 2-7, and then connected to the third connecting pipe 1-23-3 on the sealed water tank 1-23; the first reagent dispensing module includes the first solvent tank 2-10, the first metering pump 2-9, and the first metering pump check valve. The first reagent filling module includes a second solvent tank 2-13, a second metering pump 2-12, and a second metering pump check valve 2-11. The first and second reagent filling modules are connected to the fourth connecting pipe 1-23-4 of the sealed water tank via the manifold at the rear ends of the first and second metering pump check valves 2-8 and 2-11, respectively, through the fifth isolation valve 2-14 and the sixth isolation valve 2-15. The gas filling module of the water quality conditioning system may specifically include a high-pressure gas cylinder 2-16 and a low-pressure gas storage tank 2-18. The gas storage tank inlet electric valve 2-17, the first gas pressure monitoring gauge 2-19, the first safety valve 2-20, the seventh isolation valve 2-21 and the eighth isolation valve 2-22 are connected in sequence to the fifth connecting pipe 1-23-5 on the sealed water tank 1-23. The low-pressure gas storage tank 2-18 is equipped with the first gas pressure monitoring gauge 2-19 and the first safety valve 2-20.

[0066] The gas supply system is used to supply inert gas to the in-core test device 1-1 to achieve thermal insulation between high-temperature and low-temperature components, and at the same time to monitor the gas parameters inside the in-core test device 1-1 in order to determine whether the pressure boundary has been damaged. In some optional embodiments, the gas supply system includes a gas source branch and an exhaust branch. The gas source branch includes an inert gas high-pressure cylinder 3-1, an inert gas storage tank 3-3, an inert gas storage tank inlet electric valve 3-2, a second gas pressure monitoring gauge 3-4, a second safety valve 3-5, a ninth isolation valve 3-6, and a tenth isolation valve 3-7. The inert gas high-pressure cylinder 3-1, the inert gas storage tank inlet electric valve 3-2, the inert gas storage tank 3-3, the ninth isolation valve 3-6, and the tenth isolation valve 3-7 are sequentially connected and then connected to the in-core test device 1-1. The second gas pressure monitoring gauge 3-4 and the second safety valve 3-5 are configured on the inert gas storage tank 3-3. The exhaust branch may specifically include a tail gas tank 3-14, a third gas pressure monitoring gauge 3-15, a third safety valve 3-11, an eleventh isolation valve 3-12, a twelfth isolation valve 3-13, and a gas supply system pressure monitoring gauge 3-8. Gas supply system temperature monitoring gauge 3-9, gas supply system humidity monitoring gauge 3-10, eleventh isolation valve 3-12, and twelfth isolation valve 3-13 are sequentially connected to tail gas tank 3-14. Among them, eleventh isolation valve 3-12 is connected to in-core test device 1-1. Gas supply system pressure monitoring gauge 3-8, gas supply system temperature monitoring gauge 3-9, and gas supply system humidity monitoring gauge 3-10 are installed on the gas passage between eleventh isolation valve 3-12 and in-core test device 1-1. Third safety valve 3-11 is installed between tail gas tank 3-14 and in-core test device 1-1. Third gas pressure monitoring gauge 3-15 is installed on tail gas tank 3-14. During operation, if pressure, temperature, humidity, etc. exceed the standard, it indicates that there is a leak in isolation pipe 1-1-6 of in-core test device 1-1 or the pressure boundary of high temperature water. The test must be stopped immediately to ensure the safety of the research reactor and fuel rods.

[0067] In the event of a breach in the in-core test apparatus 1-1 or the primary water circulation system, the emergency water injection system supplies cooling water to the annular flow channel of the test section. In some optional embodiments, the emergency water injection system may specifically include an emergency water injection tank 4-1, a fifth electrically operated shut-off valve 4-2, a sixth electrically operated shut-off valve 4-3, a first solenoid valve 4-4, and a second solenoid valve 4-5. The fifth electrically operated shut-off valve 4-2 and the sixth electrically operated shut-off valve 4-3 are connected in series to form a first water injection channel, and the first solenoid valve 4-4 and the second solenoid valve 4-5 are connected in series to form a second water injection channel. The first and second water injection channels are connected in parallel. The emergency water injection tank 4-1 is equipped with a water level monitor 4-6. Each water injection channel forms a dual-valve isolation system, ensuring the integrity of the pressure boundary in the high-pressure section within the reactor. Furthermore, the use of two water injection channels with different valve types effectively prevents conjugate failures of the equipment, ensuring the reliability of the emergency cooling water for the in-core test apparatus. The fifth electric shut-off valve 4-2, the sixth electric shut-off valve 4-3, the first solenoid valve 4-4, and the second solenoid valve 4-5 are interlocked with the first pressure measuring instrument 1-1-18 and the second pressure measuring instrument 1-1-16 of the in-core test device 1-1. When the signals of the first pressure measuring instrument 1-1-18 and the second pressure measuring instrument 1-1-16 simultaneously drop to a specific value, the fifth electric shut-off valve 4-2, the sixth electric shut-off valve 4-3, the first solenoid valve 4-4, and the second solenoid valve 4-5 are fully opened, injecting water into the annular flow channel 1-1-27 of the test section 1-1-8 until the fuel rods are submerged. This embodiment of the application uses gravity flow to reduce the need for traditional high-temperature and high-pressure loop safety injection pumps and high-pressure gas cylinders, optimizing the system setup. Simultaneously, through a conservative design of the emergency water tank capacity, sufficient emergency cooling water supply is ensured, guaranteeing the safety of the fuel rods.

[0068] In some alternative embodiments, the in-core test apparatus 1-1, the primary water circulation system, the emergency water injection system, and the pipes and valves used in the system are configured to nuclear safety level, while the water quality conditioning system and the inert gas system are configured to non-nuclear safety level, with at least two valves used to isolate the different safety levels.

[0069] The specific embodiments described above illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. Although the description of this application is presented in conjunction with some embodiments, this does not mean that the features of this application are limited to this embodiment. On the contrary, the purpose of describing the application in conjunction with embodiments is to cover other options or modifications that may be derived based on the claims of this application. To provide a thorough understanding of this application, many specific details are included in the above description. This application may also be implemented without using these details. Furthermore, to avoid confusion or obscuring the focus of this application, some specific details will be omitted in the description. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other.

[0070] It should be noted that in this specification, similar reference numerals and letters in the above figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the figures, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. In the description of this application, it should be noted that unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two elements. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0071] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A miniaturized test system for in-reactor testing of fuel rods, characterized in that, include: In-pile test apparatus (1-1), wherein the outer diameter of the in-pile test apparatus (1-1) is not greater than 60 mm; A primary water circulation system is connected to the in-pile test apparatus (1-1); A water quality conditioning system, which is connected to the primary water circulation system to adjust the chemical parameters of the water in the primary water circulation system to a desired value; A gas supply system is connected to the in-pile test device (1-1) to supply a heat insulation medium to the in-pile test device (1-1) to achieve heat insulation between high-temperature components and low-temperature components and to monitor the integrity of pressure boundaries; An emergency water injection system is connected to the in-pile test device (1-1) by gravity flow to supply cooling water to the in-pile test device (1-1) to reduce the need for safety injection pumps and high-pressure gas cylinders. The primary water circulation system includes a sealed water tank (1-23). ​​The primary water circulation system is configured to use the pressure difference between the high pressure of the main pipeline and the low pressure of the sealed water tank (1-23) for filtration and ion exchange, thereby eliminating the need to install a charging pump. The in-pile test apparatus (1-1) includes: A central component, connected to the primary water circulation system and the emergency water injection system, includes a test section (1-1-8) and a fuel rod. The test section (1-1-8) has an upper support (1-1-23) and a lower support (1-1-25) arranged at intervals. One end of the fuel rod engages with the lower support (1-1-25), and the other end engages with the upper support (1-1-23) via a spring (1-1-24). A connecting section (1-1-7) is sleeved on the central component and one end of it is connected to the flange of the central component. A first through-pipe (1-1-4) and a second through-pipe (1-1-5) communicating with the interior of the connecting section (1-1-7) are connected to it. An isolation tube (1-1-6) is fitted onto the central assembly and connected to the flange at the other end of the connecting section (1-1-7); Wherein, the port of the first penetrating trachea (1-1-4) within the connecting section (1-1-7) is located at a position flush with the end of the central component away from the connecting section (1-1-7).

2. The miniaturized test system for in-reactor testing of fuel rods according to claim 1, characterized in that, The primary water circulation system includes: A heat exchanger (1-2) is connected to the in-pile test apparatus (1-1) to supply primary water to the in-pile test apparatus (1-1) or to receive primary water from the in-pile test apparatus (1-1); Cooler (1-3), the cooler (1-3) is connected to the heat exchanger (1-2); The first filter (1-5) is connected to the cooler (1-3); A sealed water tank (1-23) is connected to the first filter (1-5) and to the heat exchanger (1-2).

3. The miniaturized test system for in-reactor testing of fuel rods according to claim 2, characterized in that, An ion exchange module is connected between the first filter (1-5) and the sealed water tank (1-23).

4. The miniaturized test system for in-reactor testing of fuel rods according to claim 2, characterized in that, A heater (1-33) is connected between the heat exchanger (1-2) and the in-pile test device (1-1) to heat the primary water discharged from the heat exchanger (1-2).

5. The miniaturized test system for in-reactor testing of fuel rods according to claim 2, characterized in that, A fuel damage monitoring unit (1-4) is connected between the cooler (1-3) and the first filter (1-5).

6. The miniaturized test system for in-reactor testing of fuel rods according to claim 1, characterized in that, The water quality regulation system includes: A reagent dispensing module, wherein the reagent dispensing module is connected to the primary water circulation system; A gas injection module, which is connected to the primary water circulation system; A water quality monitoring unit (2-3) is used to monitor primary water in a primary water circulation system. The water quality monitoring unit (2-3) includes one or more of the following modules: pH detection module, conductivity detection module, calcium ion concentration detection module, magnesium ion concentration detection module, silicon ion concentration detection module, sodium ion concentration detection module, potassium ion concentration detection module, lithium ion concentration detection module, and boron ion concentration detection module.

7. The miniaturized test system for in-reactor testing of fuel rods according to claim 1, characterized in that, The gas supply system includes: High-pressure gas cylinders (2-16); A low-pressure gas storage tank (2-18) is connected between the high-pressure gas cylinder (2-16) and the in-pile test device (1-1); The exhaust gas tank (3-14) is connected to the in-pile test device (1-1).

8. The miniaturized test system for in-reactor testing of fuel rods according to claim 1, characterized in that, The emergency water injection system includes an emergency water injection tank (4-1), which is connected to the in-pile test device (1-1) through two parallel shut-off valve groups.

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