Pressurized water reactor fuel cladding damage release rule loop experiment system

Abstract

The utility model discloses a pressurized water reactor fuel cladding damage release rule loop experiment system which comprises a main loop device used for simulating a reactor primary loop circulation pipeline, a fuel cladding damage release simulation experiment device and a sampling measurement device. The fuel cladding breakage and release simulation experiment device comprises a single-flow-channel simulation piece, a simulation experiment rod used for simulating a broken fuel cladding and an air inlet control mechanism. The single-flow-channel simulation piece is connected in the main loop device, and the simulation experiment rod is inserted in the single-flow-channel simulation piece in a penetrating mode; the gas inlet control mechanism is connected with the simulation experiment rod and provides experiment gas including fuel cladding integrity indication nuclide substances and helium. And the sampling and measuring device is connected with the main loop device and is used for sampling and measuring. According to the utility model, the experiment research on the release of the nuclide krypton-xenon gas at the crevasse of the simulated fuel cladding and the migration behavior in the loop can be realized by the real fuel cladding integrity indication nuclide krypton-xenon gas.

Description

Technical Field

[0001] This utility model relates to the field of nuclear fuel cladding damage testing technology, and in particular to an experimental system for the release loop of pressurized water reactor fuel cladding damage. Background Technology

[0002] During nuclear power plant operation, the fuel cladding may be damaged by various physicochemical factors such as abrasion and chemical corrosion. Fission products within the fuel rods can then enter the primary coolant through the breach, potentially increasing radiation dose levels for operation and maintenance personnel and even necessitating reactor shutdown for repairs. As the first line of defense against radioactive nuclides, the integrity monitoring of the fuel cladding is a crucial component of radiochemical technical specifications. If damage occurs, the extent of the damage and the severity of the accident must be assessed promptly based on monitoring data to determine whether a reactor shutdown is necessary. To accurately assess damage, extensive experiments are required to determine the relationship between the degree of damage and the monitoring indicator nuclides in the coolant. Currently, most international experiments are conducted on experimental reactors, where experimental variables are relatively fixed, and the results lack scalability.

[0003] The published paper, "Study on the Release Law of Fission Gas from Cladding Gap to Coolant under Pressurized Water Reactor Cladding Failure Conditions," discloses a reactor cladding failure simulation experimental loop. This loop uses oxygen instead of fuel cladding to simulate the release of fission gas, and uses changes in oxygen concentration within the loop to simulate changes in fission gas concentration. The experimental loop consists of a degassing section, a pressurization section, an experimental section, a measurement section, and a main loop. The pressurization section is responsible for pressurizing and stabilizing the loop. Partial oxygen removal is performed in the degassing section to observe changes in oxygen concentration. Oxygen release is simulated in the experimental section to simulate fission gas release. The measurement section uses a dissolved oxygen meter to measure the released dissolved oxygen to simulate fission gas measurement. The main loop primarily uses pumps and heaters to achieve loop circulation and control of the loop medium temperature. However, the experimental circuit has the following shortcomings: (1) The experimental circuit uses oxygen instead of fuel cladding fission gas, and can only perform oxygen release and measurement, but cannot measure the release behavior of real fission gas components; (2) The air intake device only mentions oxygen heating through the heating device in the simulated fuel rod, and cannot perform experimental gas mixing, heating and pressurization with different component ratios at the front end, so the working conditions of fission gas release in the fuel rod that can be simulated are limited; (3) The dissolved oxygen signal measurement process using the dissolved oxygen meter will be affected by gas current signal interference, and wavelet transformation is required to eliminate interference, so direct and real measurement results cannot be obtained. Utility Model Content

[0004] The technical problem to be solved by this invention is to provide an improved experimental system for the release loop of fuel cladding failure in pressurized water reactors.

[0005] The technical solution adopted by this utility model to solve its technical problem is: to provide a pressurized water reactor fuel cladding failure and release law loop experimental system, including a main loop device for simulating the primary loop circulation pipeline of the reactor, a fuel cladding failure and release simulation experimental device, and a sampling and measurement device.

[0006] The fuel cladding failure and release simulation experimental device includes a single-channel simulator, a simulation experimental rod for simulating fuel cladding failure, and an air intake control mechanism; the single-channel simulator is connected in the main loop device, and the simulation experimental rod is inserted into the single-channel simulator; the air intake control mechanism is connected to the simulation experimental rod and provides the simulation experimental rod with an experimental gas including fuel cladding integrity indicator nuclides and helium.

[0007] The sampling and measuring device is connected to the main circuit device to sample and measure liquids and / or gases, and to obtain the composition and / or radioactivity of the liquids and / or gases.

[0008] In one embodiment, the main circuit device includes a main circuit for the flow of a coolant medium therein, a pressure regulating unit for regulating the pressure of the coolant medium in the main circuit, a temperature regulating unit for regulating the temperature of the coolant medium in the main circuit, and a gas purging unit for charging and purging the main circuit; the pressure regulating unit, the temperature regulating unit, and the gas purging unit are respectively connected to the main circuit.

[0009] In one embodiment, the main circuit includes a loop pipe and a circulation pump disposed on the loop pipe;

[0010] The pressure control unit includes a water tank, a booster pump, a buffer tank, a pressure regulator, and a pressure gauge. The inlet of the booster pump is connected to the water tank. The buffer tank is connected between the outlet of the booster pump and the loop pipe. The pressure regulator and the pressure gauge are located at the output end of the buffer tank and connected to the loop pipe.

[0011] The temperature control unit includes a heater and a temperature instrument. The heater is connected to the circuit pipe, and the temperature instrument is located at the output end of the heater.

[0012] The gas purging unit includes a gas storage tank, an inlet pipe connecting the gas storage tank and the return pipe, a gas valve and a flow meter installed on the inlet pipe.

[0013] In one embodiment, the main circuit device further includes a wastewater collection and treatment unit connected to the main circuit pipeline for collecting and treating wastewater after the experiment.

[0014] In one embodiment, the fuel cladding failure and release simulation experimental device further includes a transmission mechanism;

[0015] The simulated experimental rod includes an outer shell and an end plug. The outer shell has at least one experimental hole. The end plug fits inside the outer shell. The transmission mechanism is connected to and drives the end plug to move back and forth along the axial direction of the outer shell to close the experimental hole. The air intake control mechanism is connected to the outer shell.

[0016] In one embodiment, the single-channel simulator includes a single-channel housing and a simulated channel bar;

[0017] Both the simulated flow channel rod and the simulated experimental rod are vertically installed inside the single-flow channel housing; the lower end of the single-flow channel housing is provided with a medium inlet, and the upper end of the single-flow channel housing is provided with a medium outlet; the medium inlet and the medium outlet are respectively connected to the main circuit of the main circuit device.

[0018] In one embodiment, the air intake control mechanism includes an air supply tank, an air delivery pipe connected between the air supply tank and the test hole, and an air delivery valve disposed on the air delivery pipe; the air supply tank is provided with an air supply heating unit, and the air supply tank is connected to a pressurization unit.

[0019] In one embodiment, the sampling and measuring device includes a sampling branch, a cooling unit, a sampling unit, and a measuring unit; the sampling branch is connected to the main circuit device at the rear end of the fuel cladding failure and release simulation experimental device; the cooling unit is disposed on the sampling branch to cool and depressurize the coolant medium to be measured; the sampling unit is connected to the sampling branch to perform liquid or gas sampling; and the measuring unit is connected to the sampling unit to measure the compositional characteristics of the liquid or gas sample.

[0020] In one embodiment, the cooling unit includes a heat exchanger connected to the sampling branch and a chiller connected to the heat exchanger.

[0021] In one embodiment, the sampling unit includes a gas-liquid separation unit, a liquid sampling section and a gas sampling section connected to the gas-liquid separation unit.

[0022] In one embodiment, the measuring unit includes a measuring instrument, which includes at least one of ion chromatography, gas chromatography, and ICP-MS.

[0023] In one embodiment, the pressurized water reactor fuel cladding failure and release law loop experimental system further includes an electrical and instrumentation control system, which connects to and controls the operation of the main loop device, the fuel cladding failure and release simulation experimental device, and the sampling and measurement device, as well as performs data acquisition.

[0024] The beneficial effects of this invention are: This invention enables experimental research on the release and migration behavior of krypton-xenon gas, a real indicator of fuel cladding integrity, at simulated fuel cladding breaches. Attached Figure Description

[0025] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings:

[0026] Figure 1 This is a schematic diagram of the connection structure of an experimental system for the release law loop of pressurized water reactor fuel cladding failure according to an embodiment of this utility model;

[0027] Figure 2 yes Figure 1 Schematic diagram of the main circuit device;

[0028] Figure 3 yes Figure 1 Schematic diagram of the experimental device for simulating fuel cladding failure and release;

[0029] Figure 4 yes Figure 1 A schematic diagram of the sampling and measuring device. Detailed Implementation

[0030] To provide a clearer understanding of the technical features, objectives, and effects of this utility model, the specific embodiments of this utility model will now be described in detail with reference to the accompanying drawings.

[0031] like Figure 1 As shown, an embodiment of the pressurized water reactor fuel cladding failure and release law loop experimental system includes a main loop device 1, a fuel cladding failure and release simulation experimental device 2, a sampling and measuring device 3, and an electrical instrumentation and control system 4.

[0032] The main loop device 1 simulates the primary loop circulation pipeline of a reactor, through which the coolant medium flows. The fuel cladding breach release simulation device 2 is connected to the main loop device 1, and the coolant medium flows along the main loop device 1 while simultaneously entering and exiting the fuel cladding breach release simulation device 2. The sampling and measurement device 3 is connected to the main loop device 1 to sample and measure liquids or gases, obtaining the composition and / or radioactivity of the liquids or gases.

[0033] The electrical and instrumentation control system 4 connects to and centrally controls the operation of relevant electrical control components in the main circuit device 1, the fuel cladding failure and release simulation experimental device 2, and the sampling and measurement device 3. It also enables remote measurement and control, as well as the display, acquisition, and storage of operating parameters. The electrical and instrumentation control system 4 mainly consists of an electrical system and an instrumentation control system. The electrical system mainly includes a low-voltage distribution cabinet, an uninterruptible power supply, and cables. The instrumentation control system mainly includes a host computer, a control cabinet, an operating console, and cables.

[0034] See Figure 1 and Figure 2 The main circuit device 1 includes a main circuit for the flow of coolant medium, a pressure regulating unit 12 for regulating the pressure of coolant medium in the main circuit, a temperature regulating unit 13 for regulating the temperature of coolant medium in the main circuit, and a gas purging unit 14 for charging and purging the main circuit; the pressure regulating unit 12, the temperature regulating unit 13 and the gas purging unit 14 are respectively connected to the main circuit.

[0035] Specifically, the main loop is the core of the experimental loop, used to simulate the primary loop circulation piping of a reactor. The main loop further includes a loop pipe 11 and a circulation pump 110 installed on the loop pipe 11; the circulation pump 110 provides power to drive the coolant medium in the loop pipe 11 to circulate along the main loop.

[0036] The main circuit also includes a flow meter 111 installed on the circuit pipe 11 to display the flow rate of the coolant medium in the main circuit. The circulating pump 110 adjusts the flow rate of the main circuit through a combination of frequency conversion and bypass to ensure that the coolant flow rate in the sub-channel of the experimental apparatus reaches the experimental set value.

[0037] The pressure control unit 12 is connected to the loop pipe 11 and is located at the outlet end of the circulating pump 110, specifically between the outlet end of the circulating pump 110 and the inlet side of the fuel cladding failure and release simulation experimental device 2. The pressure control unit 12 may further include a water tank 121, a booster pump 122, a buffer tank 123, a pressure regulator 124, and a pressure gauge 125. The inlet end of the booster pump 122 is connected to the water tank 121. The buffer tank 123 is connected between the outlet end of the booster pump 122 and the loop pipe 11. The pressure regulator 124 and the pressure gauge 125 are located at the output end of the buffer tank 123 and connected to the loop pipe 11. The water tank 121 is also connected to the main loop via a pipe and a shut-off valve 126.

[0038] The pressure regulation unit 12 is used for the pressure regulation and control of the coolant medium. The water tank 121 stores a sufficient amount of coolant medium. The booster pump 122 sequentially delivers the coolant medium from the water tank 121 to the buffer tank 123 and the main circuit, thereby increasing the pressure in the main circuit. When the main circuit pressure is high, the shut-off valve 126 can be opened to pump the coolant medium from the main circuit pipeline to the water tank 121, thus depressurizing the main circuit. The buffer tank 123 is used to mitigate coolant medium pressure fluctuations in the branch of the pressure regulation unit 12, and the pressure regulator 124 is used to stabilize the pressure in the main circuit and prevent drastic pressure fluctuations. The pressure in the main circuit is measured by the pressure gauge 125. The pressure gauge 125 transmits measurement data to the electrical control system 4, enabling temperature data acquisition and control. This is primarily achieved by: when the pressure in the main circuit is lower than the set pressure, the electrical control system 4 activates the booster pump 122 to increase the pressure of the coolant medium in the main circuit; once the pressure reaches the set pressure, the electrical control system 4 disconnects the booster pump 122 to maintain the coolant medium pressure in the main circuit at the set value. This method keeps the coolant medium in the main circuit at the set pressure. The circuit's operating status can also be detected by reading the pressure gauge 125.

[0039] The temperature control unit 13 is used for regulating and controlling the temperature of the coolant medium in the main circuit. This temperature control unit 13 further includes a heater 131 and a temperature instrument 132. The heater 131 is connected to the circuit pipe 11, and the temperature instrument 132 is located at the output end of the heater 131. The heater 131 can raise the temperature of the coolant medium in the main circuit. The temperature instrument 132 is selected from any precision temperature measuring instrument suitable for high-temperature media, such as a thermocouple. It is mainly used for measuring the temperature of the coolant medium in the main circuit, and temperature data can be collected through the electrical control system 4. The measurement data of the temperature instrument 132 can be transmitted to the electrical control system 4 to realize temperature data acquisition and control. Specifically, when the temperature of the coolant medium in the main circuit is lower than the set temperature, the electrical control system 4 turns on the heater 131 to raise the temperature of the coolant medium in the main circuit; after the temperature reaches the set temperature, the electrical control system 4 disconnects the heater 131 to maintain the coolant medium temperature at the set value. This method maintains the coolant medium in the main circuit at the set temperature. The circuit operating status can also be detected by reading the temperature instrument 132.

[0040] The gas purging unit 14 is used for pre-charging the experimental gas to saturation and purging the experimental circuit to dryness after evacuation. The gas purging unit 14 may include at least one gas storage tank 141, an inlet pipe 142 connected between the gas storage tank 141 and the circuit pipe 11, a gas valve 143 and a flow meter 144 installed on the inlet pipe 142. Each gas storage tank 141, its connected inlet pipe 142, the gas valve 143 and the flow meter 144 installed on the inlet pipe 142 form a gas purging pipeline. The gas purging unit 14 may include one or more parallel gas purging pipelines.

[0041] Gas storage tank 141 contains gases such as argon, krypton, and xenon, with the type and purity depending on experimental requirements. Krypton and xenon are primarily used to pre-charge the coolant medium in the main circuit before experiments, ensuring the main circuit is saturated with experimental gases. This allows for sampling and measurement of the released experimental gases in the main circuit even at low concentrations. Argon is mainly used for purging and drying the main circuit after the experiment is completed and the circuit is emptied, to mitigate oxidation and corrosion of the experimental apparatus.

[0042] Flow meter 144, such as a mass flow meter, is used for precise control of gas mass flow rate and is employed for gas flow measurement. Gas mass flow rate data can be collected through the electrical control system 4. Gas valve 143 is used to close the inlet pipe 142. Flow measurement data can be transmitted to the electrical control system 4 to achieve gas mass flow rate data acquisition and control. Specifically, when the gas mass flow rate or total volume in the main circuit is lower than the set flow rate or total volume, the electrical control system 4 opens gas valve 143 to deliver specific gas from storage tank 141 into the main circuit; when the gas mass flow rate or total volume reaches the set flow rate or total volume, the electrical control system 4 closes gas valve 143 to stop the delivery of specific gas from storage tank 141 into the main circuit. This method achieves the delivery of specific gas with a specific gas mass flow rate or total volume into the main circuit.

[0043] In one embodiment, the main loop device 1 further includes a wastewater collection and treatment unit 15 connected to the main loop pipeline for collecting, detecting, and treating wastewater after the experiment. The wastewater collection and treatment unit 15 further includes a wastewater collection tank 151, a wastewater sampling module 152 connected to the wastewater collection tank 151, a chemical injection module 153, and a filtration module 154. After the experiment, the drain valve of the main loop is opened to transport the wastewater in the main loop to the wastewater collection tank 151. The wastewater sampling module 152 mainly includes a sampling container and a valve. By opening the valve, wastewater samples are taken into the sampling container and sent for wastewater characteristic testing. The wastewater composition determines whether it should be directly discharged or further treated. The chemical injection module 153 mainly includes a chemical injection tank and an injection valve. Chemicals are added to the wastewater collection tank 151 through the injection valve for chemical treatment of the wastewater. The filtration module 154 mainly includes a purification filter element and a circulation pump. The circulation pump circulates and filters the wastewater through the purification filter element.

[0044] See Figure 1 and Figure 3 The fuel cladding failure and release simulation experimental device 2 includes a single-channel simulation component 21, a simulation experimental rod 22, a transmission mechanism 23, and an intake control mechanism 24; the single-channel simulation component 21 is connected in the main circuit device 1, and the simulation experimental rod 22 is inserted inside the single-channel simulation component 21.

[0045] The single-channel simulator 21 includes a single-channel housing 211 and a simulated flow channel rod 212. Both the simulated flow channel rod 212 and the simulated experimental rod 22 are vertically mounted inside the single-channel housing 211 via mounting components. The single-channel housing 211 and the simulated flow channel rod 212 form the frame at the location of the single flow channel. The mounting components facilitate the installation and sealing of the simulated experimental rod 22 and the simulated flow channel rod 212 within the single-channel simulator 21. The lower end of the single-channel housing 211 has a medium inlet (not shown), and the upper end has a medium outlet (not shown). The medium inlet and the medium outlet are respectively connected to the main loop of the main loop device 1, specifically to both ends of the connection loop pipe 11, ensuring that the flow channel where the simulated flow channel rod 212 is located is similar to the actual reactor core flow channel. The medium inlet communicates with the medium outlet through the internal space of the single-channel housing 211, forming a single flow channel. The coolant medium of the main loop enters the single-channel simulator 21 from the medium inlet and flows out from the medium outlet back to the main loop.

[0046] The simulation test rod 22 further includes a test rod housing 221 and an end plug 222. The side wall of the test rod housing 221 is provided with at least one test hole (not shown) for simulating damaged fuel cladding. The end plug 222 is movably fitted inside the test rod housing 221 for opening and closing the test hole. A transmission mechanism 23 is connected to the end plug 222 and drives the end plug 222 to move back and forth along the axial direction of the test rod housing 221, thereby closing or opening the test hole.

[0047] The transmission mechanism 23 includes a transmission rod and a drive unit. The transmission rod can enter the experimental rod housing 221 from the open top and connect to the transmission interface on the end plug 222. The drive unit connects to and drives the transmission rod to move up and down, causing the end plug 222 to move back and forth longitudinally within the experimental rod housing 221. The drive unit may include a motor, and the transmission rod uses a ball screw to convert the rotational motion of the motor into linear motion, thereby driving the end plug 222 to move longitudinally. The electrical control system 4 connects to and controls the drive unit to realize the movement control of the transmission rod and obtain the movement distance and position of the end plug 222.

[0048] The air intake control mechanism 24 is connected to the experimental rod shell 221 and provides experimental gas to the experimental rod shell 221. When the experimental hole is open, the experimental gas in the experimental rod shell 221 is released into the single-channel shell 211.

[0049] In one embodiment, the gas intake control mechanism 24 includes a gas supply tank 241, a gas delivery pipe 242 connecting the gas supply tank 241 and the experimental port, and a gas delivery valve 243 installed on the gas delivery pipe 242. The gas supply tank 241 primarily stores krypton, xenon, and other fuel cladding integrity indicator nuclides, as well as carrier gases such as helium. The gas delivery valve 243 controls the opening and closing of the gas delivery pipe 242 and is also used to regulate the mass flow rate of the experimental gas. The gas supply tank 241 is equipped with a gas supply heating unit 244 for heating the experimental gas to a set temperature. The gas supply tank 241 is connected to a pressurization unit 245 for pressurizing the internal components of the gas supply tank 241; this pressurization unit 245 includes, but is not limited to, a booster pump. The gas supply tank 241 is equipped with pressure gauges and temperature gauges to monitor the internal pressure and temperature of the gas supply tank 241 in real time. The gas delivery pipe 242 is also equipped with a mass flow meter for monitoring and displaying the mass flow rate of the delivered experimental gas.

[0050] The intake control mechanism 24 described above, through the gas supply heating unit 244, pressurization unit 245, and gas delivery valve 243, achieves the regulation and control of experimental gas composition, temperature, pressure, and mass flow rate, as well as the closing control of the experimental gas transport switch. The intake control mechanism 24 is connected to the electrical instrumentation and control system 4, and the monitored data such as temperature, pressure, and mass flow rate can be transmitted to the electrical instrumentation and control system 4 to realize data acquisition and control of the electrical instrumentation and control system 4.

[0051] The intake control mechanism 24 may further include at least one gas distribution tank 246 connected to the gas supply tank 241. Depending on experimental requirements, each gas distribution tank 246 may store a single gas or a gas mixture in a specific proportion, facilitating the adjustment and control of the type and content of the intake gas components. The gas distribution tank 246 can quantitatively deliver the required specific gas to the gas supply tank 241.

[0052] See Figure 1and Figure 4 The sampling and measuring device 3 is mainly connected to the loop pipe 11 at the rear end (medium outlet) of the fuel cladding failure and release simulation experimental device 2, and is used to sample and measure the coolant medium flowing through the fuel cladding failure and release simulation experimental device 2.

[0053] In one embodiment, the sampling and measuring device 3 includes a sampling branch 31, a cooling unit 32, a sampling unit 33, and a measuring unit 34. The sampling branch 31 is a branch extending from the pipeline behind the fuel cladding failure and release simulation experimental device 2, with both its inlet and outlet located behind the device. The cooling unit 32 is installed on the sampling branch 31 to cool and depressurize the coolant medium entering the sampling branch 31 and to ensure the safety of subsequent sampling and measurement. The sampling unit 33 is connected to the sampling branch 31 and is located downstream of the cooling unit 32, performing liquid or gas sampling of the coolant medium within the sampling branch 31. The measuring unit 34 is connected to the sampling unit 33 and measures the compositional characteristics of the liquid or gas sample.

[0054] Specifically, the cooling unit 32 includes a heat exchanger 321 and a chiller 322; the heat exchanger 321 is connected to the sampling branch 31, and the coolant medium of the sampling branch 31 enters the heat exchanger 321 for heat exchange; the chiller 322 is connected to the heat exchanger 321 and provides a cold source for the heat exchanger 321.

[0055] The sampling unit 33 is located on an independent pipeline extending from the rear end of the sampling branch 31. It may include a gas-liquid separation unit 331, a liquid sampling section 332 connected to the gas-liquid separation unit 331, and a gas sampling section 333, and is mainly used for sampling liquid and gas samples. The gas-liquid separation unit 331 separates the coolant medium entering it into gas and water. The separated liquid sample enters the liquid sampling section 331 from the lower end of the gas-liquid separation unit 331, and the separated gas enters the gas sampling section 333 from the upper end of the gas-liquid separation unit 331.

[0056] The gas-liquid separation unit 331 mainly consists of a pressure-stabilizing water tank and a gas-liquid separator, primarily used for pressure-assisted stabilization and gas sample drying. The pressure-stabilizing water tank is mainly used for pressure stabilization; gas is injected into the tank through the gas sampling interface to reach the set pressure, ensuring that the coolant pressure in the tank and related pipelines remains relatively stable. The gas-liquid separator is mainly used to filter moisture from the gas phase, ensuring that the sampled gas at the downstream end is dry.

[0057] The liquid sampling section 332 can be composed of a liquid sampling valve, a liquid sampling tank, and a liquid sampling interface. The liquid sampling valve is used for closing the main liquid sampling switch, and multiple liquid sampling tanks and liquid sampling interfaces are connected in parallel at its rear end. Each liquid sampling tank, liquid sampling interface, and liquid sampling valve is equipped with a liquid sampling switch. The liquid sampling tank is mainly used for collecting liquid samples for easy external transportation, and the liquid sampling interface can be used to connect to the measurement unit 34.

[0058] The gas sampling section 333 can be composed of a gas sampling valve, a gas sampling canister, and a gas sampling interface. The gas sampling valve is located after the gas-liquid separation unit 331 and is used for closing the main gas sampling switch. Multiple gas sampling canisters and gas sampling interfaces are connected in parallel at its rear end. Each gas sampling canister, gas sampling interface, and gas sampling valve is connected to a gas sampling switch. The gas sampling canister is mainly used for collecting gas samples for easy external transport, and the gas sampling interface can be used to connect to the measurement unit 34.

[0059] The measurement unit 34 is located at the rear end of the liquid sampling interface and the gas sampling interface. It mainly includes measuring instruments, including at least one of ion chromatography, gas chromatography, and ICP-MS, which are used to measure the composition characteristics of the liquid and gas samples to be measured. The specific configuration of the instruments is adjusted according to the experimental requirements.

[0060] This invention enables experiments on the release behavior of krypton-xenon gas, an indicator of fuel cladding integrity. The breach release and loop migration behavior of krypton-xenon gas can realistically reflect the release behavior of krypton-xenon gas in a reactor. The gas intake control mechanism can regulate and control the composition, temperature, and pressure of the experimental gas, effectively reproducing the composition of fission gases within the fuel rods under different burn-up cycles and operating conditions. The gas purging unit serves two purposes: firstly, it allows for pre-charging of the loop to saturate it with experimental gas, enabling sampling and measurement of the released gas even at low concentrations; secondly, after the experiment and purging of the main loop, it purges and dries the main loop to mitigate oxidation and corrosion of the experimental apparatus. The sampling and measurement device enables continuous sampling and measurement of the released experimental gas. The wastewater collection and treatment unit enables the collection, detection, and treatment of wastewater after the experiment.

[0061] The above description is merely an embodiment of this utility model and does not limit the patent scope of this utility model. Any equivalent structural or procedural transformations made based on the description and drawings of this utility model, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this utility model.

Claims

1. An experimental system for the release loop of fuel cladding failure in a pressurized water reactor, characterized in that, This includes a main loop device for simulating the primary loop circulation pipeline of a reactor, a fuel cladding failure and release simulation experimental device, and a sampling and measurement device; The fuel cladding failure and release simulation experimental device includes a single-channel simulator, a simulation experimental rod for simulating fuel cladding failure, and an air intake control mechanism; the single-channel simulator is connected in the main loop device, and the simulation experimental rod is inserted into the single-channel simulator; the air intake control mechanism is connected to the simulation experimental rod and provides the simulation experimental rod with an experimental gas including fuel cladding integrity indicator nuclides and helium. The sampling and measuring device is connected to the main circuit device to sample and measure liquids and / or gases, and to obtain the composition and / or radioactivity of the liquids and / or gases.

2. The experimental system for the release loop of pressurized water reactor fuel cladding failure according to claim 1, characterized in that, The main circuit device includes a main circuit for the flow of coolant medium therein, a pressure regulating unit for regulating the pressure of the coolant medium in the main circuit, a temperature regulating unit for regulating the temperature of the coolant medium in the main circuit, and a gas purging unit for charging and purging the main circuit; the pressure regulating unit, the temperature regulating unit and the gas purging unit are respectively connected to the main circuit.

3. The experimental system for the release loop of pressurized water reactor fuel cladding failure according to claim 2, characterized in that, The main circuit includes a circuit pipe and a circulation pump installed on the circuit pipe; The pressure control unit includes a water tank, a booster pump, a buffer tank, a pressure regulator, and a pressure gauge. The inlet of the booster pump is connected to the water tank. The buffer tank is connected between the outlet of the booster pump and the loop pipe. The pressure regulator and the pressure gauge are located at the output end of the buffer tank and connected to the loop pipe. The temperature control unit includes a heater and a temperature instrument. The heater is connected to the circuit pipe, and the temperature instrument is located at the output end of the heater. The gas purging unit includes a gas storage tank, an inlet pipe connecting the gas storage tank and the return pipe, a gas valve and a flow meter installed on the inlet pipe.

4. The experimental system for the release loop of pressurized water reactor fuel cladding failure according to claim 2, characterized in that, The main circuit device also includes a wastewater collection and treatment unit connected to the main circuit pipeline for collecting and treating wastewater after the experiment.

5. The experimental system for the release loop of pressurized water reactor fuel cladding failure according to claim 1, characterized in that, The fuel cladding failure and release simulation experimental device also includes a transmission mechanism; The simulated experimental rod includes an outer shell and an end plug. The outer shell has at least one experimental hole. The end plug fits inside the outer shell. The transmission mechanism is connected to and drives the end plug to move back and forth along the axial direction of the outer shell to close the experimental hole. The air intake control mechanism is connected to the outer shell.

6. The experimental system for the release loop of pressurized water reactor fuel cladding failure according to claim 5, characterized in that, The single-channel simulation component includes a single-channel housing and a simulated flow channel bar; Both the simulated flow channel rod and the simulated experimental rod are vertically installed inside the single-flow channel housing; the lower end of the single-flow channel housing is provided with a medium inlet, and the upper end of the single-flow channel housing is provided with a medium outlet; the medium inlet and the medium outlet are respectively connected to the main circuit of the main circuit device.

7. The experimental system for the release loop of pressurized water reactor fuel cladding failure according to claim 5, characterized in that, The air intake control mechanism includes an air supply tank, an air supply pipe connected between the air supply tank and the test hole, and an air supply valve installed on the air supply pipe; the air supply tank is equipped with an air supply heating unit, and the air supply tank is connected to a pressurization unit.

8. The experimental system for the release loop of pressurized water reactor fuel cladding failure according to claim 1, characterized in that, The sampling and measurement device includes a sampling branch, a cooling unit, a sampling unit, and a measurement unit. The sampling branch is connected to the main circuit device at the rear end of the fuel cladding failure and release simulation experimental device. The cooling unit is located on the sampling branch to cool and depressurize the coolant medium to be measured. The sampling unit is connected to the sampling branch to sample liquids or gases. The measurement unit is connected to the sampling unit to measure the compositional characteristics of the liquid or gas samples.

9. The experimental system for the release loop of pressurized water reactor fuel cladding failure according to claim 8, characterized in that, The cooling unit includes a heat exchanger connected to the sampling branch and a chiller connected to the heat exchanger; The sampling unit includes a gas-liquid separation unit, a liquid sampling section and a gas sampling section connected to the gas-liquid separation unit; The measurement unit includes a measuring instrument, which includes at least one of ion chromatography, gas chromatography, and ICP-MS.

10. The experimental system for the release loop of pressurized water reactor fuel cladding failure according to any one of claims 1-9, characterized in that, The pressurized water reactor fuel cladding failure and release law loop experimental system also includes an electrical and instrumentation control system, which connects to and controls the operation of the main loop device, the fuel cladding failure and release simulation experimental device, and the sampling and measurement device, as well as performs data acquisition.

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