Device and method for simulating migration of fission products in liquid lead bismuth fluid

Abstract

The invention discloses a device and method for simulating migration of fission products in liquid lead bismuth fluid, the device is composed of a shell and a sealing cover, the shell of the device comprises a gas injection pipeline, a lead bismuth valve, a gas injection port, an exhaust pipeline, an exhaust valve, an exhaust port, a gas supply pipeline, a gas supply valve, a gas supply port, a heating wire, a liquid level meter, a liquid level measuring hole, a thermocouple and a temperature measuring hole, the sealing cover comprises a pressure gauge interface and a connecting screw hole. The lead bismuth valve is used for cutting off gas and liquid lead bismuth, the gas supplementing pipeline, the gas supplementing valve and the gas supplementing port are used for supplementing gas into the device to replace original gas, the pressure gauge connector in the sealing top cover is used for containing a pressure gauge, and the connecting screw hole is used for connecting the sealing top cover and the device shell. The device provided by the invention can meet the experimental research on the migration characteristics of gas or aerosol in liquid lead bismuth fluid with different crevasse sizes, different crevasse shapes and different heights, and can obtain the gas release speed and the aerosol release share under different pressures and crevasse parameters.

Description

Technical Field

[0001] The present invention belongs to the technical field of fission product migration research in liquid lead-bismuth fluid, and in particular relates to a device and method for simulating the migration of fission products in liquid lead-bismuth fluid. Background Art

[0002] When the reactor is in operation, the core fuel assembly will produce a large amount of radioactive fission products during the fission process. However, the fuel cladding may be damaged due to micro-abrasion, foreign body abrasion, chemical corrosion, irradiation creep and swelling, and the high pressure of fission products in the fuel cladding, thereby releasing fission products into the coolant. In addition to the common fission gases, the fission products released from the breach also include solid fission products and liquid fission products. In the program calculation, liquid and solid fission products are generally simulated by aerosol particles. At present, in the process of conducting the source term analysis of the lead-bismuth reactor mechanism, the aerosol fraction released from the breach is assumed to have an assumed value, which introduces uncertainty into the source term calculation results. Therefore, it is urgent to conduct relevant experimental research on the complex physical process of the release of fission products from fuel elements to liquid lead-bismuth alloy coolant in the lead-bismuth fast reactor to obtain the key parameters of the fission product migration process, such as the gas release rate and the total release fraction of the aerosol after the release, to provide support for model development and source term analysis calculation. Summary of the invention

[0003] In order to solve the above-mentioned problems existing in the prior art, the purpose of the present invention is to provide a device and method for simulating the migration of fission products in liquid lead-bismuth fluid, which can be used to study the aerosol washing behavior characteristics of different rupture shapes and sizes, different gas injection pressures, and different liquid lead-bismuth heights.

[0004] In order to achieve the above object, the present invention is implemented by the following technical solutions:

[0005] A device for simulating the migration of fission products in a liquid lead-bismuth fluid, the device comprising a shell 1-1, a liquid level measuring hole 1-2, a liquid level gauge 1-3, a temperature measuring hole 1-4, a thermocouple 1-5, a heating wire 1-6, an exhaust port 1-7, an exhaust pipeline 1-8, an exhaust valve 1-9, an air supply port 1-10, an air supply pipeline 1-11, an air supply valve 1-12, an air injection port 3-1, an air injection pipeline 3-2, a lead-bismuth valve 3-3, a sealing cover 2-1, a pressure gauge interface 2-2, and a connecting screw hole 2-3;

[0006] The shell 1-1 is used as a container for carrying liquid lead and bismuth and as a place for experiments, and the upper part of the shell 1-1 is a gas space;

[0007] The gas injection port 3-1 and the gas injection pipeline 3-2 are located at the bottom of the shell, and are used to connect the high-pressure gas cylinder and the device, and are used to inject aerosol into the device to replace the fission products in the lead-bismuth pile;

[0008] The lead-bismuth valve 3-3 is located on the gas injection pipeline 3-2 and is used to cut off the gas and prevent liquid lead-bismuth from flowing back into the gas injection pipeline;

[0009] The exhaust port 1-7 is located in the upper gas space of the housing 1-1, the exhaust pipe 1-8 is connected to the exhaust port 1-7 outside the device, and the exhaust valve 1-9 is located on the exhaust pipe 1-8, which is used to exhaust the gas in the upper gas space of the device as a whole;

[0010] The gas replenishment port 1-10 is located in the gas space above the housing 1-1, the gas replenishment pipeline 1-11 is connected to the gas replenishment port 1-10 outside the device, and the gas replenishment valve 1-12 is located on the gas replenishment pipeline 1-11, and is used to replenish gas into the device to meet the gas flow requirement of the measuring instrument when the gas injection flow rate is small, and at the same time can replace the gas originally existing in the gas space above the device;

[0011] The heating wire 1-6 surrounds the entire outer shell 1-1 and is used to heat and keep the entire device warm;

[0012] The liquid level measuring hole 1-2 and the liquid level meter 1-3 are arranged on the housing 1-1 and are used to measure the liquid level height of the liquid lead and bismuth in the device;

[0013] The temperature measuring hole 1-4 and the thermocouple 1-5 are arranged on the inner wall of the housing 1-1 and are used to measure the temperature of the liquid lead and bismuth in the device;

[0014] The pressure gauge interface 2-2 on the sealing cover is used to place a pressure gauge, which is located at the top of the entire device and is used to measure the pressure of the gas space inside the device to prevent overpressure;

[0015] The connecting screw hole 2-3 is used to connect the sealing cover 2-1 and the housing 1-1.

[0016] The shell 1-1 is a cylindrical box, including a lower liquid area and an upper gas space. The diameter of the upper gas space is three times that of the lower liquid area. The box is made of metal material and has good pressure and temperature resistance.

[0017] The metal material is high temperature resistant stainless steel.

[0018] The bottom of the shell 1-1 is prefabricated with multiple gas injection ports 3-1 of different sizes in the circumferential direction, and multiple gas injection ports 3-1 of the same size are prefabricated in the axial direction. The unused gas injection ports are blocked with lead-bismuth valves 3-3, which are opened when in use to meet the different gas injection port parameters.

[0019] The gas injection port 3 - 1 is prefabricated in different shapes and sizes according to specific needs, including circular, rectangular or diamond-shaped.

[0020] The exhaust pipe 1-8 is also used as a sampling pipe to extract the gas washed with liquid lead and bismuth for measurement.

[0021] Based on the above background technology, the technical problems solved by the present invention are:

[0022] 1. The device of the present invention has the ability to measure the particle concentration of fission products after passing through the lead-bismuth coolant, which solves the problem that it is difficult to measure the release ratio of the fission products of the lead-bismuth pile in the coolant;

[0023] 2. The device of the present invention solves the problem of gas injection and sampling measurement in liquid lead and bismuth.

[0024] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0025] 1. The device of the present invention can obtain the migration characteristics of aerosol in lead-bismuth fluid under different gas injection pressures and breach parameters, and provide experimental data support for the source term research of lead-bismuth pile mechanism;

[0026] 2. The device shell is designed to be stainless steel that can withstand high temperatures, similar to the actual lead-bismuth pile. The device is designed with a heating wire that can meet the temperature conditions of the lead-bismuth fluid;

[0027] 3. The device is designed with gas injection ports of different heights and sizes, which can realize experiments with different breach parameter conditions;

[0028] 4. The diameter of the gas space designed at the top of the device is three times that of the liquid area at the bottom, which constructs a larger gas space and can prevent the hidden danger of pressurization caused by excessive gas entering.

[0029] 5. The device has a compact structure and is easy to manufacture. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of this application, and do not constitute a limitation of the embodiments of the present invention. In the drawings:

[0031] Figure 1 It is a front view and a cross-sectional view of the device of the present invention.

[0032] Figure 2 It is a top view of the device of the present invention.

[0033] Figure 3 The invention discloses a gas injection port design for the device of the present invention.

[0034] 1-1-housing, 1-2-liquid level measuring hole, 1-3-liquid level gauge, 1-4-temperature measuring hole, 1-5-thermocouple, 1-6-heating wire, 1-7-exhaust port, 1-8-exhaust pipe, 1-9-exhaust valve, 1-10-air supply port, 1-11-air supply pipe, 1-12-air supply valve, 2-1-sealing cover, 2-2-pressure gauge interface, 2-3-connecting screw hole, 3-1-air injection port, 3-2-air injection pipe, 3-3-lead-bismuth valve. DETAILED DESCRIPTION

[0035] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0036] like Figure 1 , Figure 2 and Figure 3 As shown, the present invention is a device for simulating the migration of fission products in a liquid lead-bismuth fluid, the device comprising a shell 1-1, a liquid level measuring hole 1-2, a liquid level gauge 1-3, a temperature measuring hole 1-4, a thermocouple 1-5, a heating wire 1-6, an exhaust port 1-7, an exhaust pipeline 1-8, an exhaust valve 1-9, an air supply port 1-10, an air supply pipeline 1-11, an air supply valve 1-12, an air injection port 3-1, an air injection pipeline 3-2, a lead-bismuth valve 3-3, a sealing cover 2-1, a pressure gauge interface 2-2, and a connecting screw hole 2-3;

[0037] The shell 1-1 is used as a container for carrying liquid lead and bismuth and as a place for experiments, and the upper part of the shell 1-1 is a gas space;

[0038] The gas injection port 3-1 and the gas injection pipeline 3-2 are located at the bottom of the shell, and are used to connect the high-pressure gas cylinder and the device, and are used to inject aerosol into the device to replace the fission products in the lead-bismuth pile;

[0039] The lead-bismuth valve 3-3 is located on the gas injection pipeline 3-2 and is used to cut off the gas and prevent liquid lead-bismuth from flowing back into the gas injection pipeline;

[0040] The exhaust port 1-7 is located in the upper gas space of the housing 1-1, the exhaust pipe 1-8 is connected to the exhaust port 1-7 outside the device, and the exhaust valve 1-9 is located on the exhaust pipe 1-8, which is used to exhaust the gas in the upper gas space of the device as a whole;

[0041] The gas replenishment port 1-10 is located in the gas space above the housing 1-1, the gas replenishment pipeline 1-11 is connected to the gas replenishment port 1-10 outside the device, and the gas replenishment valve 1-12 is located on the gas replenishment pipeline 1-11, and is used to replenish gas into the device to meet the gas flow requirement of the measuring instrument when the gas injection flow rate is small, and at the same time can replace the gas originally existing in the gas space above the device;

[0042] The heating wire 1-6 surrounds the entire outer shell 1-1 and is used to heat and keep the entire device warm;

[0043] The liquid level measuring hole 1-2 and the liquid level meter 1-3 are arranged on the housing 1-1 and are used to measure the liquid level height of the liquid lead and bismuth in the device;

[0044] The temperature measuring hole 1-4 and the thermocouple 1-5 are arranged on the inner wall of the housing 1-1 and are used to measure the temperature of the liquid lead and bismuth in the device;

[0045] The pressure gauge interface 2-2 on the sealing cover is used to place a pressure gauge, which is located at the top of the entire device and is used to measure the pressure of the gas space inside the device to prevent overpressure;

[0046] The connecting screw hole 2-3 is used to connect the sealing cover 2-1 and the housing 1-1.

[0047] Preferably, Figure 1 As shown, the housing 1-1 is a cylindrical box, including a lower liquid area and an upper gas space, the diameter of the upper gas space is three times that of the lower liquid area, and a larger gas space is constructed to prevent the hidden danger of pressurization caused by excessive gas entering. The box is made of metal material and has good pressure and temperature resistance.

[0048] Preferably, the metal material is made of high temperature resistant stainless steel, which is similar to the actual lead-bismuth pile.

[0049] Preferably, a plurality of gas injection ports 3-1 of different sizes are prefabricated circumferentially at the bottom of the shell 1-1, and a plurality of gas injection ports 3-1 of the same size are prefabricated axially. Unused gas injection ports are blocked with lead-bismuth valves 3-3, which are opened when in use to meet the different gas injection port parameters.

[0050] Preferably, the gas injection port 3 - 1 is prefabricated in different shapes and sizes according to specific needs, including circular, rectangular or diamond-shaped.

[0051] Preferably, the exhaust pipe 1-8 is also used as a sampling pipe to extract the gas washed with liquid lead and bismuth for measurement. Such a one-pipe-for-multiple-purpose design can save space in the experimental device and ensure the simplicity and beauty of the device.

[0052] The method for using the device for simulating the migration of fission products in liquid lead-bismuth fluid comprises the following steps:

[0053] First, assemble the entire device and check to ensure that all parts are working properly, all connections are well sealed, there is no obvious damage or leakage, and the gas supply meets the demand;

[0054] Add solid lead-bismuth blocks into the housing 1-1 of the device, at which time the sealing cover 2-1 is not sealed, turn on the heating wire 1-6 to a predetermined power and maintain it for a preset time to melt the lead-bismuth in the device, and determine whether the liquid lead-bismuth has reached a specified height by using the lead-bismuth liquid level data measured by the liquid level meter 1-3. After reaching the specified height, adjust the power of the heating wire 1-6 to a heat preservation state;

[0055] After the lead and bismuth melt and reach the preset height, let it stand for a preset time to observe whether there is liquid leakage in the entire device, especially the gas injection port 3-1. If there is, the entire device needs to be reassembled and sealed; if not, it means that the entire device is well sealed and meets the subsequent requirements;

[0056] Connect the sealing cover 2-1 and the housing 1-1 to seal the entire device; open the exhaust valve 1-9 and the air supply valve 1-12, connect the air supply pipeline 1-11 to the external high-pressure gas cylinder, and inject gas into the upper gas space of the device for replacement. After all the gas in the upper gas space is replaced, close the exhaust valve 1-9 and the air supply valve 1-12;

[0057] Connect an external aerosol gas injection device to a designated gas injection pipeline 3-2, start the aerosol gas injection device and open the lead-bismuth valve 3-3 to inject aerosol with a known particle concentration into the device, and open the exhaust valve 1-9 to exhaust the gas outwards, select the designated exhaust pipeline as a sampling pipeline to sample the washed gas, use an external particle size spectrometer to measure its particle concentration, and compare the particle concentration before and after aerosol washing to obtain the washing efficiency of the fission product migration process, thereby obtaining the release share of the fission product through the lead-bismuth coolant; during the gas injection process, it is necessary to pay attention to the gas pressure in the device at all times. If there is a significant increase, it is necessary to open more exhaust pipelines for exhaust;

[0058] After the injection and measurement phases, turn off the aerosol injection device and the measuring equipment, clean the residual aerosol in the experimental system, and record and organize the experimental data; according to the different working conditions set, change different injection pressures and injection ports, and conduct the experiment in the same way.

[0059] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A device for simulating the migration of fission products in liquid lead-bismuth fluid, It is characterized in that The device comprises a housing (1-1), a liquid level measuring hole (1-2), a liquid level meter (1-3), a temperature measuring hole (1-4), a thermocouple (1-5), a heating wire (1-6), an exhaust port (1-7), an exhaust pipeline (1-8), an exhaust valve (1-9), an air supply port (1-10), an air supply pipeline (1-11), an air supply valve (1-12), an air injection port (3-1), an air injection pipeline (3-2), a lead-bismuth valve (3-3), a sealing cover (2-1), a pressure gauge interface (2-2), and a connecting screw hole (2-3); The shell (1-1) serves as a container for carrying liquid lead and bismuth and a place for experiments, and the upper part of the shell (1-1) is a gas space; The gas injection port (3-1) and the gas injection pipeline (3-2) are located at the bottom of the shell, and are used to connect the high-pressure gas cylinder and the device, and are used to inject aerosol into the device to replace the fission products in the lead-bismuth pile; The lead-bismuth valve (3-3) is located on the gas injection pipeline (3-2) and is used to cut off the gas and prevent liquid lead-bismuth from flowing back into the gas injection pipeline; The exhaust port (1-7) is located in the upper gas space of the housing (1-1); the exhaust pipe (1-8) is connected to the exhaust port (1-7) outside the device; the exhaust valve (1-9) is located on the exhaust pipe (1-8), and is used as a whole to exhaust gas from the upper gas space in the device; The gas supply port (1-10) is located in the gas space above the housing (1-1); the gas supply pipeline (1-11) is connected to the gas supply port (1-10) outside the device; the gas supply valve (1-12) is located on the gas supply pipeline (1-11) and is used to supply gas to the device when the gas injection flow rate is small to meet the gas flow requirement of the measuring instrument, and at the same time, can replace the gas originally existing in the gas space above the device; The heating wire (1-6) surrounds the entire outer surface of the housing (1-1) and is used to heat and keep the entire device warm; The liquid level measuring hole (1-2) and the liquid level meter (1-3) are arranged on the housing (1-1) and are used to measure the liquid level height of liquid lead and bismuth in the device; The temperature measuring hole (1-4) and the thermocouple (1-5) are arranged on the inner wall of the housing (1-1) and are used to measure the temperature of liquid lead and bismuth in the device; The pressure gauge interface (2-2) on the sealing cover is used to place a pressure gauge, which is located at the top of the entire device and is used to measure the pressure of the gas space inside the device to prevent overpressure; The connecting screw hole (2-3) is used to connect the sealing cover (2-1) and the outer shell (1-1).

2. The device for simulating the migration of fission products in liquid lead-bismuth fluid according to claim 1, It is characterized in that The shell (1-1) is a cylindrical box body, including a lower liquid area and an upper gas space, the diameter of the upper gas space is three times that of the lower liquid area, and the box body is made of metal material and has good pressure and temperature resistance.

3. The device for simulating the migration of fission products in liquid lead-bismuth fluid according to claim 2, It is characterized in that The metal material is high temperature resistant stainless steel.

4. The device for simulating the migration of fission products in liquid lead-bismuth fluid according to claim 1, It is characterized in that The bottom of the shell (1-1) is prefabricated with a plurality of gas injection ports (3-1) of different sizes in the circumferential direction, and a plurality of gas injection ports (3-1) of the same size are prefabricated in the axial direction; unused gas injection ports are blocked with lead-bismuth valves (3-3); the lead-bismuth valves (3-3) are opened when in use, thereby meeting the requirements of different gas injection port parameters.

5. The device for simulating the migration of fission products in liquid lead-bismuth fluid according to claim 3, It is characterized in that The gas injection port (3-1) is prefabricated in different shapes and sizes according to specific needs, including circular, rectangular or diamond shapes.

6. The device for simulating the migration of fission products in liquid lead-bismuth fluid according to claim 1, It is characterized in that The exhaust pipe (1-8) is also used as a sampling pipe to extract the gas washed with liquid lead and bismuth for measurement.

7. A method for using the device for simulating the migration of fission products in liquid lead-bismuth fluid as claimed in any one of claims 1 to 6, It is characterized in that The method comprises the following steps: First, assemble the entire device and check to ensure that all parts are working properly, all connections are well sealed, there is no obvious damage or leakage, and the gas supply meets the demand; A solid lead-bismuth block is added into the housing (1-1) of the device, at which time the sealing cover (2-1) is not sealed, the heating wire (1-6) is turned on to a predetermined power and maintained for a preset time to melt the lead-bismuth in the device, and the lead-bismuth liquid level data measured by the liquid level meter (1-3) is used to determine whether the liquid lead-bismuth has reached a specified height, and after reaching the specified height, the power of the heating wire (1-6) is adjusted to a heat preservation state; After the lead and bismuth melt and reach a preset height, the device is left to stand for a preset time to observe whether there is any liquid leakage in the entire device, especially the gas injection port (3-1). If there is, the entire device needs to be reassembled and sealed; if not, it means that the entire device has good sealing performance and meets subsequent requirements; Connect the sealing cover (2-1) and the housing (1-1) to seal the entire device; open the exhaust valve (1-9) and the air supply valve (1-12), connect the air supply pipeline (1-11) to the external high-pressure gas cylinder, inject gas into the upper gas space of the device for replacement, and after all the gas in the upper gas space is replaced, close the exhaust valve (1-9) and the air supply valve (1-12); Connect an external aerosol gas injection device to a designated gas injection pipeline (3-2), start the aerosol gas injection device and open the lead-bismuth valve (3-3) to inject aerosol with a known particle concentration into the device, and open the exhaust valve (1-9) to exhaust the gas outward, select the designated exhaust pipeline as a sampling pipeline to sample the gas after washing, use an external particle size spectrometer to measure its particle concentration, and compare the particle concentration before and after aerosol washing to obtain the washing efficiency of the fission product migration process, thereby obtaining the release share of the fission product through the lead-bismuth coolant; during the gas injection process, it is necessary to pay attention to the gas pressure in the device at all times, and if there is a significant increase, it is necessary to open more exhaust pipelines for exhaust; After the injection and measurement phases, turn off the aerosol injection device and the measuring equipment, clean the residual aerosol in the experimental system, and record and organize the experimental data; according to the different working conditions set, change different injection pressures and injection ports, and conduct the experiment in the same way.

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