CN114999682B - Passive residual heat hydraulic test device and method for polar environment nuclear power device - Google Patents

Abstract

The test device comprises an ice making circulation loop and a pool type passive waste heat discharging system test loop, wherein the ice making loop in the ice making circulation loop is connected with a centrifugal pump through a check valve to form a test heat exchange water pool inlet, and an outlet pipeline of the heat exchange water pool is connected with the centrifugal pump and then enters the ice making loop inlet to form a circulation loop. The outlet pipeline of the electric heating evaporator in the test loop of the pool type passive waste heat discharging system is connected with the upper inlet of the tube bundle type heater, the outlet pipeline of the tube bundle type heat exchanger is connected with the shell side inlet of the shell type cooling system, and the shell side outlet pipeline of the shell type cooling system is connected with the inlet of the electric heating evaporation system to form a loop. The invention can simulate the thermal hydraulic characteristics of the passive waste heat discharging system of the nuclear power plant under the environment of motion and extreme low temperature superposition, and provides an effective test device for the related research of the thermal hydraulic characteristics of the passive waste heat discharging system in the environment of extreme low temperature.

Description

Thermal-hydraulic test device and method for passive residual exhaust of nuclear power plant in polar environment

technical field

The invention belongs to the thermal-hydraulic characteristic test field of a passive waste heat discharge system of a nuclear power plant in a polar environment, and specifically relates to a thermal-hydraulic test device and a method for a passive waste heat discharge thermal-hydraulic test device and method of a nuclear power plant in a polar environment.

Background technique

With global climate change, there is a longer summer ice-free period in the seas of the Arctic region. Compared with conventional powered ships, nuclear power devices have the advantages of strong endurance, high energy density, and small fuel volume, and can operate in the harsh environment of the polar regions. Various navigation missions. At present, my country's polar nuclear power plants started relatively late, and most of them are based on active safety systems. In the event of a safety accident, they must rely on external power input to drive pumps and other mechanical devices to provide sufficient cooling water for the reactor to prevent the core temperature from being too high. High occurrence of meltdown accidents. The three major nuclear accidents in history all reflect the great limitations of active safety devices. The purpose of the passive safety design is to inject the coolant into the core for cooling for a period of time by relying only on gravity, natural circulation of the coolant, expansion of compressed air and other natural forces without relying on external energy input, and then export the heat of the coolant , to ensure sufficient and continuous cooling of the core. The passive waste heat removal system is put into operation after the failure of the normal waste heat removal system, and uses the process of coolant evaporation and condensation to realize the natural circulation in the system loop to export the core decay waste heat. In the low-temperature environment, due to the solid ice crystals mixed in the seawater, it is easy to block the seawater system of the ship under the condition of poor heat transfer performance, resulting in the inability of cooling water to flow in and the effect that the heat exchanger cannot be effectively cooled.

Chinese Patent Application Publication No. CN106653109A discloses a test and research device for secondary side passive waste heat removal system, including three water tank simulation bodies, evaporator simulation body and other devices, which are used to simulate secondary side passive waste heat in third-generation reactor technology Reliability of discharge system design. The simulation object of this invention is the static reactor passive safety system on land, and it is impossible to simulate the influence of the ocean movement environment on the passive waste heat removal system. At the same time, the invention uses liquid water for cooling, which is not suitable for simulating waste heat removal and heat transfer under low temperature conditions. Heat transfer flow test of ice-water mixture.

Chinese patent application publication number CN209149828U discloses a multi-loop coupled passive waste heat removal system test device. The condensing pipe at the inlet of the passive waste heat removal system is connected to the steam outlet on the secondary side of the steam generator, which can simulate the natural circulation conditions of the three circuits. This device also uses the liquid water in the water tank to conduct heat exchange tests on the waste heat discharge heat exchanger. Without an ice making circuit, it is impossible to conduct heat exchange simulation tests under low temperature conditions.

Chinese Patent Application Publication No. CN201589481U discloses a system for producing fluidized ice using seawater. The device is mainly composed of cooling compressors, condensers, ice-making heat exchangers, drying filters and other equipment, and can use seawater crystallization technology. The principle can continuously make a mixture of seawater and ice crystals, but the system loop cannot regulate the proportion of ice crystals in seawater, so it is not suitable for research that requires precise control of the proportion of ice crystals for heat transfer experiments in low-temperature environments.

Contents of the invention

In view of the requirement that the above-mentioned inventive device is not applicable to the thermal-hydraulic characteristic test of nuclear power equipment under the superimposed state of ocean motion and low temperature conditions, a thermal-hydraulic test device and method for passive residual exhaust of nuclear power plant in polar environment are proposed. The present invention can simulate the motion working condition encountered by the ship on the ocean through the corresponding motion platform equipment, and study the influence of the tilting and rocking motion on the flow and heat transfer characteristics of the system. The simulation of low temperature heat transfer conditions is realized by coupling the ice making loop with the passive waste heat removal system loop. Among them, the ice-making circuit can adjust the proportion of ice crystals in the prepared ice-water mixture to meet the needs of testing the influence of different ice crystal concentrations on heat transfer characteristics.

In order to meet the above test purpose, the present invention adopts the following technical solutions:

A thermal-hydraulic test device for passive residual heat removal of a nuclear power plant in a polar environment, including an ice-making circulation loop and a pool-type passive waste heat removal system test loop, wherein the ice-making circulation loop includes an ice-making loop 11 and a six-degree-of-freedom motion heat exchange The pool 12 and the ice making circuit 11 mainly include an ice maker 1 , an ice storage and heat preservation container 2 connected to the ice maker and a low-temperature water tank 301 . The main function of the low-temperature water tank 301 is to deploy seawater to provide sufficient water source for the ice machine, and at the same time, it can also inject low-temperature seawater into the ice storage and heat preservation container 2 to prepare the ice-water mixture with the proportion of ice crystals required for the test.

The ice-making circuit 11 is located upstream of the ice-water mixture circulation circuit, and its output pipeline is connected to the first centrifugal pump 401 through the second check valve 802, and the prepared fixed ratio mixture is injected into the circulation circuit pipeline, and the downstream outlet pipeline of the first centrifugal pump 401 The third control valve 703 is connected with the first flow monitoring instrument 901 for controlling the flow input of the inlet pipe of the test heat exchange pool and detecting the flow upstream of the test circulation loop. A first temperature monitoring instrument 1001 is installed at the inlet of the test heat exchange pool 5 to monitor the temperature parameters of the inlet fluid. The bottom of the test heat exchange pool 5 is connected to the upper support surface of the six-degree-of-freedom motion platform, which is fixed with bolts. The lower support surface of the six-degree-of-freedom movement platform is also fixed on the ground with bolts, and the upper and lower support surfaces are connected by six piston hydraulic rods. The second temperature monitoring instrument 1002 located at the outlet of the test heat exchange pool bottom monitors the temperature parameters of the outlet fluid of the test heat exchange pool, and the outlet pipe of the test heat exchange pool is connected with the second flow monitoring instrument 902 and the fourth control valve 704 for monitoring The downstream flow of the test heat exchange pool and the adjustment of the output flow of the test heat exchange pool are connected with a differential pressure sensor 18 between the inlet and outlet pipes of the test heat exchange pool to measure the pressure difference change of the fluid passing through the test heat exchange pool. The downstream outlet pipeline of the fourth control valve 704 is connected to the second centrifugal pump 402 to provide sufficient driving force to realize the flow circulation of the ice-water mixture fluid. The downstream of the second centrifugal pump 402 is connected to the inlet pipeline of the ice storage and heat preservation container to form a circulation loop.

The test circuit of the pool-type passive waste heat removal system includes an electric heating evaporation system 13 , a tube-bundle heat exchanger 14 , a shell-and-tube heat exchange system 17 and a water supply tank 303 . The main function of the electric heating evaporation system 13 is to heat the liquid water in the water supply tank 303 into the steam required for the test, and control the corresponding steam parameters according to the test requirements. The downstream pipeline of the electric heating evaporation system 13 is connected to the fifth control valve 705 and the third control valve 705. The flow meter 903 is used to monitor and control the steam flow. The downstream pipeline of the third flowmeter 903 is connected to the upper tube side inlet of the tube bundle heat exchanger 14, and the tube side inlet pipeline is provided with a third temperature sensor 1003 to monitor the temperature parameters of the steam entering the tube side inlet of the tube bundle heat exchanger. The tube-bundle heat exchanger 14 is immersed in the ice-water mixture fluid in the test heat exchange pool 5 for heat exchange, and the heat exchange characteristics with the low-temperature fluid are studied. The outlet pipe of the tube-bundle heat exchanger is located at the lower end of the tube-bundle heat exchanger 14. There is a certain height difference from the entrance to facilitate the formation of natural circulation. The outlet pipe at the lower end of the tube bundle heat exchanger 14 is connected to the fourth flowmeter 904 and the sixth control valve 706 to control and monitor the fluid flow rate at the outlet of the heat exchanger for waste heat discharge, and at the same time, the outlet pipe at the lower end is provided with a fourth temperature sensor 1004 to monitor the fluid temperature at the outlet of the tube bundle parameter. The downstream of the sixth control valve 706 is connected to the shell-side inlet of the shell-and-tube heat exchange system 17. The shell-and-tube heat exchange system 17 is used to condense the incompletely condensed steam in the pipeline into liquid water for reheating into steam. When the fluid temperature is too high, it is cooled to prevent accidents. In the shell-and-tube heat exchange system 17, the shell side downstream of the electric heating evaporator 15 is connected to the inlet of the electric heating evaporation system 13, and the condensed fluid is reintroduced into the electric heating evaporator for heating to form a circulation loop. In the shell-and-tube heat exchange system 17, the tube side of the electrically heated evaporator 15 passes through the seventh control valve 707, the water pump 16, and the cooling water tank 302 to form a closed loop in sequence, so that the shell-side fluid circulates and the heat of the tube-side fluid is exported.

The ice-making circuit 11 can control the content of ice crystals in the ice-water mixture.

A baffle plate is used in the test heat exchange pool 5 to divide the flow space into two parts, and the outlet is located at the bottom of the test heat exchange pool 5 .

The surfaces of the connecting pipes in the ice-making circulation loop are all covered with thermal insulation materials, which can maintain the operating temperature of the loop within the range of -5°C to 0°C.

The outside of the tube bundle heat exchanger 14 is in direct contact with the ice-water mixture at -5°C-0°C, and the steam at 320°C-350°C flows inside the tube.

The test heat exchange pool 5 in the six-degree-of-freedom motion heat exchange pool has a transparent observation window for observing the flow pattern change of the ice-water mixture.

The six-degree-of-freedom motion bench 6 has multiple piston support rods connecting the upper support surface and the lower support surface, and the test heat exchange pool 5 and the upper support surface are fixed by bolts.

According to the test method of the thermal-hydraulic test device for the passive residual discharge of the nuclear power plant in the polar environment, the ice-making circulation loop is turned on when the polar low-temperature environment simulation test is carried out, and the electric heating evaporator 15 is turned on at the same time to generate 320°C-350°C Steam, so that high-temperature steam passes through the tube bundle heat exchanger tube 14, and the outside of the tube contacts the ice-water mixture at -5°C-0°C, and the passive waste heat removal system is simulated by adjusting the horizontal angle of the support surface on the six-degree-of-freedom motion platform 6 The thermal-hydraulic characteristic process under the polar low temperature environment superimposed ocean tilting conditions, the flow, temperature and pressure parameters of each circulation loop in the process are measured by the first to fourth flow monitoring instruments, the first to fourth temperature monitoring instruments, differential The pressure sensor 18 measures; during the test process, the ice-water mixture is extracted from the ice storage and heat preservation container 2 to detect and determine the content of ice crystal particles, and the flow pattern change of the ice-water mixture is observed and measured through the observation window of the test heat exchange pool 5. In the test heat exchange pool 5 Sampling at the inlet and outlet respectively to detect the content change of ice crystal particles before and after the heat exchange process, so as to study the dynamic characteristics of ice crystal particles during the heat exchange process.

Compared with the prior art, the present invention has the following advantages:

1. The test system and method of the present invention can simulate the thermal-hydraulic characteristics of the passive waste heat removal system of the nuclear power plant under the superimposed state of the ocean motion environment and the low temperature environment, and conduct an investigation on the performance and reliability of the passive waste heat removal system in a special environment. Sufficient experimental research;

2. The ice-making circulation circuit of the present invention can study the influence of flow pattern characteristics of different ice-water mixtures on the heat transfer characteristics, and the melting of ice crystals during heat transfer by testing the transparent observation window of the heat transfer pool and the sampling data in the ice storage insulation container. The dynamic behavior characteristics of the process.

3. Realize the simulation of the ship's working conditions in the ocean through the motion platform. The six-degree-of-freedom motion platform can simulate the roll, pitch, heel, and trim of the ship along the different coordinate axes of the coordinate system in the ocean by tilting and swinging. Effect of isomotion on passive waste heat removal system.

Description of drawings

Figure 1 is a system diagram of the ice making cycle loop.

Figure 2 is a diagram of the passive waste heat removal system.

Detailed ways

The present invention is described in detail below in conjunction with accompanying drawing and example:

As shown in Fig. 1 and Fig. 2, the present invention is a thermal-hydraulic test device for passive residual discharge of a nuclear power plant in a polar environment. The main function of the low-height ice storage and heat preservation container 2 is to inject the low-temperature seawater configured in the low temperature water tank 301 into the ice storage heat preservation container 2 by gravity to adjust the ratio of ice crystal particles and water. The outlet of the low-temperature water tank 301 passes through the first control valve 701 through the insulation pipe and then connects to the inlet pipe of the ice maker 1 at a lower height to provide the ice maker 1 with seawater required for ice making. During the test, the first control valve 701 between the low-temperature water tank 301 and the ice maker 1 is preferentially opened to inject low-temperature seawater into the ice maker 1 to start making ice. When the ice crystal particles in the ice maker meet the basic requirements of the test, open The output port of the ice maker allows the mixture fluid to enter the ice storage and heat preservation container 2, and measures the ice crystal content of the ice-water mixture therein. During this process, the second control valve 702 of the outlet pipeline of the low-temperature water tank 301 is opened to inject low-temperature seawater into the ice storage and heat preservation container 2 to further regulate the ice crystal content. A first check valve 801 is provided on the insulation pipeline between the ice maker 1 and the ice storage and insulation container 2 to prevent the ice-water mixture from flowing back.

As shown in Figure 1, the downstream of the outlet pipeline of the ice storage and heat preservation container 2 is connected with the second check valve 802 and the first centrifugal pump 401, and the outlet of the ice storage and heat preservation container 2 is closed during the preparation of the ice-water mixture. After the test requirement, open the output port of the ice storage and heat preservation container 2, the third control valve 703 and the first centrifugal pump 401 to introduce the ice-water mixture into the ice-making circulation circuit pipeline, and keep the state of controlling the opening of the third control valve 703, and keep the fourth Control the closed state of the valve 704. When the water level of the ice-water mixture fluid in the test heat exchange pool 5 reaches the test requirement, adjust the opening degree of the fourth control valve 704 and the power of the second centrifugal pump 402 to make the test heat exchange pool 5 The inlet and outlet flows are kept in balance, and the internal water level is always within the range required by the test. In the process of keeping the water level stable, the first flow monitoring instrument 901 and the second flow monitoring instrument 902 record the flow data at the inlet and outlet of the test heat exchange pool 5, and the first temperature monitoring instrument 1001 and the second temperature monitoring instrument 1002 record the test exchange flow data. The temperature data of the fluid at the inlet and outlet of the hot water pool 5 is recorded by the differential pressure sensor 18 as the pressure drop data after the fluid passes through the test heat exchange pool.

Figure 2 is the test circuit of the pool-type passive waste heat removal system. During the test operation, the seventh control valve 707 and the water pump 16 are opened in sequence to circulate the cooling water on the tube side of the shell-and-tube heat exchange system 17. When the ice-making circulation circuit can maintain the water level in the heat exchange pool stable, open the eighth control valve 708 to inject the corresponding amount of water into the water supply tank 303 according to the steam parameter requirements of the test, and then keep the fifth control valve 705 and the sixth control valve 706 open , gradually increase the power of the electric heating evaporator to generate steam, record the flow data displayed by the third flowmeter 903 and the fourth flowmeter 904, and turn off the independent loop water pump 16 of the shell-and-tube heat exchange system 17 when the steam demand reaches the required parameters of the test. The steam in the pipe is cooled by the test heat exchange pool 5 and a natural circulation is established. After the test device is fully started, observe the ice crystal melting phenomenon through the transparent window of the test heat exchange pool 5, judge the flow pattern characteristics of the ice-water mixture, record the test heat exchange pool 5 and the tube bundle heat exchanger 14, the inlet and outlet flow rates through each monitoring system, Pressure, temperature parameters change. During the shutdown stage of the test, the independent loop water pump 16 of the shell-and-tube heat exchange system 17 was turned on for additional condensation, and the power of the electric heating evaporation system 13 was gradually reduced. After the electric heating evaporation system 13 is completely closed, close the ice maker 1 and the second control valve 702 of the low-temperature pool, and at the same time close the first control valve 701 and the first centrifugal pump 401, and keep the fourth control valve 704 and the second centrifugal pump 402 until all the ice-water mixture in the loop pipeline is pumped into the ice storage and heat preservation container 2, and finally close the fourth control valve 704 and the second centrifugal pump 402 to clean up the residual debris at the bottom of the test heat exchange pool.

Claims (8)

1. A thermal-hydraulic test device for passive residual heat removal of a nuclear power plant in a polar environment, including an ice-making cycle circuit and a pool-type passive waste heat removal system test circuit; The ice-making circulation loop includes an ice-making loop (11) and a six-degree-of-freedom motion heat exchange pool (12), and the ice-making loop (11) includes an ice maker (1) connected by an insulation pipeline, an ice storage insulation container (2) and the low-temperature water tank (301), the ice crystals in the ice-storage insulation container (2) are used to store the ice-water mixture input by the ice machine (1), between the ice machine (1) and the ice-storage insulation container (2) The first check valve (801) is set on the insulation pipeline to prevent the ice-water mixture from flowing back; The first control valve (701) and the second control valve (702) on the pipeline control the flow; the ice-water mixture output from the ice storage container (2) enters the output pipeline and passes through the second check valve (802). A centrifugal pump (401) is driven into the main pipeline of the ice-making circulation circuit; the six-degree-of-freedom motion heat exchange pool (12) is composed of a six-degree-of-freedom motion bench (6), and the test set on the six-degree-of-freedom motion bench (6) The heat exchange pool (5) consists of a differential pressure sensor (18) installed between the inlet and outlet of the test heat exchange pool (5); the ice-water mixture output by the first centrifugal pump (401) upstream of the six-degree-of-freedom movement heat exchange pool (12) After entering the main pipeline of the ice-making circulation loop, it passes through the third control valve (703), the first flow monitoring instrument (901) and the first temperature monitoring instrument (1001) in sequence, and then enters the wall inlet pipeline of the test heat exchange pool (5); The fluid output from the outlet pipe on the bottom surface of the heat exchange pool (5) enters the main pipe of the ice making circulation circuit and then passes through the second temperature monitoring instrument (1002), the second flow monitoring instrument (902), the fourth control valve (704) and the second The centrifugal pump (402) enters into the ice storage heat preservation container (2) to form a circuit; The test circuit of the pool type passive waste heat removal system includes an electric heating evaporation system (13), a tube bundle heat exchanger (14), a shell and tube heat exchange system (17) and a water supply tank (303); the electric heating evaporation system ( 13) The main function is to heat the liquid water in the water supply tank (303) into the steam required for the test, and control the corresponding steam parameters according to the test requirements. The downstream pipeline of the electric heating evaporation system (13) is connected to the fifth control valve (705) And the third flowmeter (903), used to monitor and control the steam flow; the downstream pipeline of the third flowmeter (903) is connected to the tube side inlet on the upper end of the tube bundle heat exchanger (14), and the tube side inlet pipeline is provided with a third temperature sensor (1003), monitoring the steam temperature parameter entering the tube side inlet of the tube bundle heat exchanger; the tube bundle heat exchanger (14) is immersed in the ice-water mixture fluid in the test heat exchange pool (5) for heat exchange, and research and The heat transfer characteristics of the low-temperature fluid, the outlet pipe of the tube bundle heat exchanger is located at the lower end of the tube bundle heat exchanger (14), and there is a certain height difference from the inlet to facilitate the formation of natural circulation; the outlet pipe at the lower end of the tube bundle heat exchanger (14) is connected to the second The four flowmeters (904) and the sixth control valve (706) control and monitor the outlet fluid flow rate of the waste heat discharge heat exchanger, and at the same time, the fourth temperature sensor (1004) is installed on the outlet pipe at the lower end to monitor the temperature parameters of the outlet fluid of the tube bundle; the sixth control The downstream of the valve (706) is connected to the shell-side inlet of the shell-and-tube heat exchange system (17). When the fluid temperature in the test loop is too high, it is cooled to prevent accidents; in the shell-and-tube heat exchange system (17), the shell side of the electric heating evaporator (15) is connected to the inlet of the electric heating evaporation system (13) downstream, and the condensed The fluid is re-introduced into the electric heating evaporation system for heating to form a circulation loop; in the shell-and-tube heat exchange system (17), the tube side of the electric heating evaporator (15) passes through the seventh control valve (707), the water pump (16) and the cooling water tank ( 302) A closed circuit is formed, so that the fluid on the shell side circulates and the heat of the fluid on the tube side is exported. 2. A thermal-hydraulic test device for passive residual exhaust of a nuclear power plant in a polar environment according to claim 1, wherein the ice-making circuit (11) can control the ice crystal content in the ice-water mixture. 3. The thermal-hydraulic test device for passive residual exhaust of a nuclear power plant in a polar environment according to claim 1, wherein a baffle plate is used in the test heat exchange pool (5) to divide the flow space into two parts. part, the outlet is located at the bottom of the test heat exchange pool (5). 4. The thermal-hydraulic test device for passive residual discharge of a nuclear power plant in a polar environment according to claim 1, wherein the surfaces of the connecting pipes in the ice-making circulation loop are covered with heat-insulating materials to enable the loop to run The temperature is maintained in the range of -5°C to 0°C. 5. The thermal-hydraulic test device for passive residual exhaust of a nuclear power plant in a polar environment according to claim 1, characterized in that the tube-bundle heat exchanger (14) is connected with ice water at -5°C-0°C outside the tube The mixture is in direct contact, and steam at 320°C-350°C flows in the tube. 6. A kind of thermal-hydraulic test device for passive residual discharge of nuclear power plant in polar environment according to claim 1, characterized in that, the test heat exchange pool (5) in the six-degree-of-freedom motion heat exchange pool has a transparent observation window. To observe the change of flow pattern of ice-water mixture. 7. A kind of thermal-hydraulic test device for passive residual discharge of nuclear power plant in polar environment according to claim 1, characterized in that, the six-degree-of-freedom motion bench (6) has multiple piston support rods connected to the upper support surface and The lower support surface, the test heat exchange pool (5) and the upper support surface are fixed by bolts. 8. The test method of a passive residual exhaust thermal-hydraulic test device for a nuclear power plant in a polar environment according to any one of claims 1 to 7, characterized in that: the ice-making circulation loop is opened when performing a simulation test of a polar low-temperature environment, At the same time, the electric heating evaporator (15) is turned on to generate steam at 320°C-350°C, so that high-temperature steam passes through the tube bundle heat exchanger (14), and the outside of the tube contacts the ice-water mixture of -5°C-0°C. The horizontal angle of the support surface on the high-degree motion platform (6) simulates the thermal-hydraulic characteristic process of the passive waste heat removal system in the polar low-temperature environment superimposed on the ocean tilting condition. In this process, the flow, temperature and pressure parameters of each circulation loop are passed The first to fourth flow monitoring instruments, the first to fourth temperature monitoring instruments, and the differential pressure sensor (18) measure; during the test process, the ice-water mixture is extracted from the ice storage and heat preservation container (2) to detect and determine the content of ice crystal particles. Through the observation window of the test heat exchange pool (5), observe and measure the flow pattern change of the ice-water mixture, take samples at the entrance and exit of the test heat exchange pool (5), and detect the content change of ice crystal particles before and after the heat exchange process, so as to study the effect of ice crystal particles on heat exchange. Kinetic characteristics of the process.

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