Experimental Device and Method for the Flow Resistance Characteristics of the Continuous Phase in the Rod Bundle Channel of a Nuclear Reactor

Abstract

Experimental device and method for the flow resistance characteristics of the continuous phase in the rod bundle channel of a nuclear reactor. The experimental device includes a gas supply system, a support table, an experimental section cylinder, a rod bundle channel, an upper top cover, a crucible, a sealing plug, a high-speed camera, and a simulated working fluid preparation system; the gas supply system can provide air with different flow rates and pressures; the support table provides support and fixation for the experimental section cylinder and the rod bundle channel; the experimental section cylinder is an integrated acrylic glass cylinder; the rod bundle channel simulates the 2×2 rod bundle structure arrangement of a nuclear reactor; the upper top cover provides positioning for the crucible and the rod bundle; after the combination of the crucible and the sealing plug, the simulated working fluid can be released into the rod bundle channel; the liquid flow front is tracked by a high-speed camera to measure the liquid velocity; simulated working fluids with different physical properties are prepared through the simulated working fluid preparation system; the present invention also provides an experimental method; by conducting experiments on the flow resistance characteristics of the continuous phase in the rod bundle channel of a nuclear reactor, the present invention provides key data for the safety design of nuclear reactors.

Description

Technical Field

[0001] The present invention relates to the technical field of research on the flow resistance characteristics of the continuous phase in the rod bundle channel of a nuclear reactor, and specifically relates to an experimental device and method for the flow resistance characteristics of the continuous phase in the rod bundle channel of a nuclear reactor. Background Art

[0002] After a core meltdown accident occurs in a nuclear reactor, with the large-scale melting of core materials, local molten pools will form in some areas of the core. When the solidification shell at the bottom cannot support the weight of the molten material above, the solidification shell fails, and the molten pool migrates downward and flows in the rod bundle channel in the form of a continuous phase. The molten material migration process has a great impact on the progress of the core meltdown accident. Currently, the experiments carried out on the molten material migration process are all integrated whole-process experiments, and various factors (including steam cooling, cladding oxidation, molten material oxidation, etc.) are considered during the experiment, which is not conducive to the analysis of individual influencing factors during the model development process and cannot accurately obtain the wall friction resistance relationship and gas friction resistance relationship of the continuous phase in the rod bundle channel. Therefore, it is necessary to focus on carrying out single-effect experiments to study the flow resistance characteristics of the continuous phase in the rod bundle channel of a nuclear reactor. Summary of the Invention

[0003] In order to overcome the problems existing in the above-mentioned prior art, the purpose of the present invention is to provide an experimental device and method for the flow resistance characteristics of the continuous phase in the rod bundle channel of a nuclear reactor, so as to provide an experimental device and method for the study of the single-effect mechanism of the flow resistance of the continuous phase in the rod bundle channel of a nuclear reactor.

[0004] To achieve the above purpose, the present invention adopts the following technical solutions:

[0005] Experimental device for the flow resistance characteristics of the continuous phase in the rod bundle channel of a nuclear reactor, comprising a gas supply system 1, a carrier 2, an experimental section cylinder 3, a rod bundle channel 4, an upper top cover 5, a crucible 6, a sealing plug 7 and a high-speed camera 8; the gas supply system 1 compresses air into a steel gas cylinder through an air compressor, and the steel gas cylinder is connected to the gas inlet ferrule 31 of the experimental section cylinder through a valve 101 and corresponding pipelines, and a flowmeter 201 and a pressure gauge 301 are installed on the pipelines to monitor the gas flow rate and pressure; the carrier 2 is composed of a stainless steel base 21, a stainless steel gland 22 and a sealing ring 23, the stainless steel base 21 provides support and fixation for the experimental section cylinder 3, and the stainless steel gland 22 realizes axial sealing and fixation of the rod bundle channel 4 by pressing the sealing ring 23; the experimental section cylinder 3 is installed in the top groove of the stainless steel base 21, and the enclosed space forms a gas flow channel. A circular through hole is opened at the bottom of the experimental section cylinder 3 and connected to an inlet pipe 32, and the inlet pipe 32 is connected to the gas supply system 1 through a gas inlet ferrule 31; the rod bundle channel 4 is arranged in a 2×2 rod bundle structure to simulate the rod bundle distribution of a nuclear reactor. The top of each simulation rod is connected to the bottom of the crucible 6, and the bottom penetrates through the stainless steel base 21 and is fixed and sealed through the stainless steel gland 22 and the sealing ring 23; the upper top cover 5 is matched with the top boss of the experimental section cylinder (3) and is sealed through a rubber ring; the upper part of the crucible 6 is an annular container, and a simulated working medium is placed in the crucible 6; a circular through hole is opened at the bottom of the crucible 6 to release the simulated working medium into the rod bundle channel 4; a sealing plug 7 is plugged on the circular through hole of the crucible 6 to control the loading and release of the simulated working medium; the high-speed camera 8 is supported and fixed by a tripod and horizontally shoots the flow condition of the simulated working medium in the rod bundle channel 4; the experimental system also includes a supporting simulated working medium preparation system 9.

[0006] The experimental section cylinder 3 is a square sleeve 33, and the upper top cover 5 is square and is matched with the top boss of the square sleeve 33.

[0007] The square sleeve 33 is made of acrylic glass as the processing material, which is convenient for observing the flow condition of the simulated working medium in the internal rod bundle channel through the high-speed camera 8.

[0008] The simulation rods of the rod bundle channel 4 are made of Zr-4 alloy material as the processing material to simulate the surface properties of the nuclear reactor cladding.

[0009] The simulated working medium preparation system 9 mainly includes glycerol, an ultrapure water machine, a beaker, a high-precision electronic balance and a rubber dropper. Deionized water is prepared by the ultrapure water machine, and glycerol aqueous solutions with different mass fractions are prepared through the beaker, the high-precision electronic balance and the rubber dropper, and liquids with different viscosities are simulated through glycerol aqueous solutions with different mass fractions.

[0010] Four through holes are provided at the outer periphery of the bottom of the stainless-steel gland 22, and it is connected to the stainless-steel base 21 through four bolts. Four through holes are provided in the middle of the stainless-steel gland 22, and the simulated rod bundle of the rod bundle channel 4 passes through these through holes. There is a boss at the top of the stainless-steel gland 22 for pressing the sealing ring 23 in the groove of the stainless-steel base 21 to achieve axial sealing and fixing of the rod bundle channel 4.

[0011] Four special-shaped through holes are provided at the four corners of the upper top cover 5 and are connected to the atmosphere to prevent the pressure in the gas flow channel from being too high, resulting in the inability of the chemical working medium in the crucible 6 to be released into the rod bundle channel 4 through the circular through holes.

[0012] The bottom of the crucible 6 is a two-stage boss. The first-stage boss is placed on the upper top cover 5, and the second-stage boss is inserted into the gas flow channel of the experimental section cylinder 3 through the circular through hole of the upper top cover 5. Four grooves are dug at the bottom of the second-stage boss for fixing the top of the simulated rod of the rod bundle channel 4. A circular through hole is provided at the bottom of the crucible 6 to release the chemical working medium into the rod bundle channel 4.

[0013] The experimental method of the experimental device for studying the continuous-phase flow resistance characteristics in the rod bundle channel of a nuclear reactor. The experimental method is realized through the following steps:

[0014] Before the experiment starts, all valves are kept closed. The surface of the simulated rod bundle of the rod bundle channel 4 is cleaned with alcohol and dried. The sealing plug 7 is tightly plugged into the through hole at the bottom of the crucible 6. After preparing glycerol aqueous solutions with different mass fractions using the beaker, high-precision electronic balance, and rubber dropper of the chemical working medium preparation system 9, a preset volume of glycerol aqueous solution is poured into the crucible 6. Adjust the focal length, height, and distance of the high-speed camera 8 and adjust it to be horizontal.

[0015] When studying the continuous-phase wall friction resistance in the rod bundle channel of a nuclear reactor, turn on the high-speed camera 8. Vertically pull out the sealing plug 7 and stop the experiment when all the chemical working medium in the crucible 6 flows into the bottom of the rod bundle channel 4. Turn off the high-speed camera 8 and study the continuous-phase wall friction resistance characteristics in the rod bundle channel of a nuclear reactor through the captured flow process.

[0016] When studying the continuous-phase gas friction resistance in the rod bundle channel of a nuclear reactor, open the valve 101 of the gas supply system 1, monitor the gas flow rate and pressure through the flow meter 201 and the pressure gauge 301, and adjust the valve 101 to the preset gas flow rate and pressure. Turn on the high-speed camera 8. Vertically pull out the sealing plug 7 and stop the experiment when all the chemical working medium in the crucible 6 flows into the bottom of the rod bundle channel 4. Turn off the high-speed camera 8 and study the continuous-phase gas friction resistance characteristics in the rod bundle channel of a nuclear reactor through the captured flow process.

[0017] Compared with the prior art, the present invention has the following advantages:

[0018] 1. The experimental device of the present invention is simple to install and disassemble, highly operable in experiments, and adopts a 2×2 rod bundle arrangement of the nuclear reactor, which can effectively simulate the flow process of the continuous-phase melt in the rod bundle channel;

[0019] 2. The experimental device of the present invention uses a glycerol aqueous solution, a room-temperature substitute material, as the modeling working fluid to study the flow resistance characteristics of the continuous phase in the nuclear reactor rod bundle channel. The material is easily obtained, the cost can be saved, the experimental temperature is low, and the experimental operability is high. Other factors such as heat transfer and oxidation can be excluded from affecting the flow and migration process of the continuous phase in the nuclear reactor rod bundle channel;

[0020] 3. The experimental device of the present invention has a wide range of experimental parameter conditions. The gas flow rate ranges from 0 to 20 m 3 / h, and the viscosity range of the modeling working fluid is 0.1 - 1 Pa·s. The flow resistance characteristics of the continuous phase in the nuclear reactor rod bundle channel can be obtained under different gas flow velocity conditions and different liquid Reynolds numbers;

[0021] 4. The experimental device of the present invention adopts a scheme of a visualization sleeve plus a high-speed camera to record the whole experimental process, and can record in real time data such as the flow pattern and position change of the continuous phase in the nuclear reactor rod bundle channel during the experiment. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the experimental device for the flow resistance characteristics of the continuous phase in the nuclear reactor rod bundle channel of the present invention.

[0023] Figure 2 It is a schematic diagram of the experimental section of the experimental device for the flow resistance characteristics of the continuous phase in the nuclear reactor rod bundle channel of the present invention.

[0024] Figure 3 It is a schematic diagram of the stainless steel gland of the experimental device for the flow resistance characteristics of the continuous phase in the nuclear reactor rod bundle channel of the present invention.

[0025] Figure 4 It is a schematic diagram of the upper top cover of the experimental device for the flow resistance characteristics of the continuous phase in the nuclear reactor rod bundle channel of the present invention.

[0026] Figure 5 It is a schematic diagram of the crucible of the experimental device for the flow resistance characteristics of the continuous phase in the nuclear reactor rod bundle channel of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0027] The present invention will be described in detail below in conjunction with the drawings and specific embodiments:

[0028] As Figure 1As shown in the figure, the present invention is an experimental device for the flow resistance characteristics of the continuous phase in the rod bundle channel of a nuclear reactor. The experimental device includes a gas supply system 1, a carrier table 2, an experimental section cylinder 3, a rod bundle channel 4, an upper top cover 5, a crucible 6, a sealing plug 7, and a high-speed camera 8. The gas supply system 1 compresses air into a steel gas cylinder through an air compressor. The steel gas cylinder is connected to the gas inlet ferrule 31 of the experimental section cylinder 3 through a valve 101 and corresponding pipelines. A flowmeter 201 and a pressure gauge 301 are installed on the pipelines to monitor the gas flow rate and pressure. The simulated working fluid preparation system 9 mainly includes glycerol, an ultrapure water machine, a beaker, a high-precision electronic balance, and a rubber dropper. Deionized water is prepared by the ultrapure water machine, and glycerol aqueous solutions with different mass fractions are prepared through the beaker, the high-precision electronic balance, and the rubber dropper. The glycerol aqueous solutions with different mass fractions are used to simulate liquids with different viscosities as the simulated working fluid, and the viscosity range of the simulated working fluid is 0.1 - 1 Pa·s.

[0029] As Figure 2 shown, the carrier table 2 is composed of a stainless steel base 21, a stainless steel gland 22, and a sealing ring 23. The stainless steel base 21 provides support and fixation for the experimental section cylinder 3. The stainless steel gland 22 realizes axial sealing and fixation of the rod bundle channel 4 by pressing the sealing ring 23. A square sleeve 33 is installed in the top groove of the stainless steel base 21, and the enclosed space forms a gas flow channel. A circular through-hole is opened at the bottom of the square sleeve 33 and connected to an air inlet pipe 32. The air inlet pipe 32 is connected to the gas supply system 1 through the gas inlet ferrule 31. The rod bundle channel 4 is arranged in a 2×2 rod bundle structure to simulate the rod bundle distribution in a nuclear reactor. The top of each simulated rod is connected to the bottom of the crucible 6, and the bottom penetrates through the stainless steel base 21 and is fixed and sealed by the stainless steel gland 22 and the sealing ring 23. The upper top cover 5 is square and matches with the top boss of the square sleeve 33 and is sealed by a rubber ring. The upper part of the crucible 6 is an annular container, and the simulated working fluid is placed in the crucible 6. A circular through-hole is opened at the bottom of the crucible 6 to release the simulated working fluid into the rod bundle channel 4. A sealing plug 7 is plugged on the circular through-hole of the crucible 6 to control the loading and release of the simulated working fluid. The high-speed camera 8 is supported and fixed by a tripod and horizontally shoots the flow condition of the simulated working fluid in the rod bundle channel 4.

[0030] As a preferred embodiment of the present invention, the square sleeve 33 is made of acrylic glass as the processing material, which is convenient for observing the flow condition of the simulated working fluid in the internal rod bundle channel through the high-speed camera 8.

[0031] As a preferred embodiment of the present invention, the simulated rods of the rod bundle channel 4 are made of Zr-4 alloy material as the processing material to simulate the surface properties of the nuclear reactor cladding.

[0032] As Figure 3As shown, as a preferred embodiment of the present invention, four through holes are opened in the outer periphery of the bottom of the stainless steel gland 22 and are connected to the stainless steel base 21 through four bolts; four through holes are opened in the middle of the stainless steel gland 22, and the simulated rod bundles of the rod bundle channel 4 pass through these through holes; there is a boss at the top of the stainless steel gland 22 for pressing the sealing ring 23 in the groove of the stainless steel base 21 to achieve axial sealing and fixing of the rod bundle channel 4.

[0033] As Figure 4 shown, as a preferred embodiment of the present invention, four special-shaped through holes are opened at the four corners of the upper top cover 5 and are connected to the atmosphere to prevent the pressure in the gas flow channel from being too high, resulting in the inability of the chemical working medium in the inner mold of the crucible 6 to be released into the rod bundle channel 4 through the circular through holes.

[0034] As Figure 5 shown, as a preferred embodiment of the present invention, the bottom of the crucible 6 is a two-stage boss. The first-stage boss is placed on the upper top cover 5, and the second-stage boss is inserted into the gas flow channel of the square sleeve 33 through the circular through hole of the upper top cover 5. Four grooves are dug at the bottom of the second-stage boss for fixing the top of the simulated rod of the rod bundle channel 4; a circular through hole is opened at the bottom of the crucible 6 to release the chemical working medium into the rod bundle channel 4.

[0035] For the experimental device for the characteristics of the continuous phase flow resistance in the rod bundle channel of the nuclear reactor of the present invention, the specific experimental operation process is as follows:

[0036] Before the experiment starts, all valves are kept closed; the surface of the simulated rod bundle of the rod bundle channel 4 is cleaned with alcohol and dried; the sealing plug 7 is tightly plugged into the bottom through hole of the crucible 6. After preparing glycerol aqueous solutions with different mass fractions by using the beaker, high-precision electronic balance and rubber head dropper of the chemical working medium preparation system 9, a preset volume of glycerol aqueous solution is poured into the crucible 6; the focal length, height and distance of the high-speed camera 8 are adjusted and it is adjusted to be horizontal.

[0037] When studying the wall friction resistance of the continuous phase in the rod bundle channel of the nuclear reactor, the high-speed camera 8 is turned on; the sealing plug 7 is vertically pulled out. When all the chemical working medium in the crucible 6 flows into the bottom of the rod bundle channel 4, the experiment is stopped, the high-speed camera 8 is turned off, and the wall friction resistance characteristics of the continuous phase in the rod bundle channel of the nuclear reactor are studied through the photographed flow process.

[0038] When studying the gas friction resistance of the continuous phase in the rod bundle channel of the nuclear reactor, the valve 101 of the gas supply system 1 is opened, and the gas flow rate and pressure are monitored through the flowmeter 201 and the pressure gauge 301. The gas flow rate range is 0-20m 3 / h, adjust the valve 101 to the preset gas flow rate and pressure; turn on the high-speed camera 8; vertically pull out the sealing plug 7, and stop the experiment when all the molten working fluid in the crucible 6 flows into the bottom of the rod bundle channel 4. Then turn off the high-speed camera 8, and study the friction resistance characteristics of the continuous-phase gas in the nuclear reactor rod bundle channel through the photographed flow process.

[0039] The above content is a further detailed description of the present invention in combination with specific principles. It cannot be determined that the specific implementation of the present invention is limited to this. For those skilled in the art to which the present invention pertains, any simple deduction or substitution made without departing from the concept of the present invention should be within the protection scope of the present invention.

Claims

1. An experimental device for the flow resistance characteristics of the continuous phase in the rod bundle channel of a nuclear reactor, characterized in that: It includes a gas supply system (1), a carrier table (2), an experimental section cylinder (3), a rod bundle channel (4), an upper top cover (5), a crucible (6), a sealing plug (7) and a high-speed camera (8); the gas supply system (1) compresses air into a steel gas cylinder through an air compressor, and the steel gas cylinder is connected to the gas inlet ferrule (31) of the experimental section cylinder through a valve (101) and corresponding pipelines. A flowmeter (201) and a pressure gauge (301) are installed on the pipelines to monitor the gas flow rate and pressure; the carrier table (2) is composed of a stainless steel base (21), a stainless steel gland (22) and a sealing ring (23). The stainless steel base (21) provides support and fixation for the experimental section cylinder (3), and the stainless steel gland (22) realizes axial sealing and fixation of the rod bundle channel (4) by pressing the sealing ring (23); the experimental section cylinder (3) is installed in the top groove of the stainless steel base (21), and the enclosed space forms a gas flow channel. A circular through hole is opened at the bottom of the experimental section cylinder (3) and connected to an inlet pipe (32), and the inlet pipe (32) is connected to the gas supply system (1) through the gas inlet ferrule (31); the rod bundle channel (4) is arranged in a 2×2 rod bundle structure to simulate the rod bundle distribution of a nuclear reactor. The top of each simulation rod is connected to the bottom of the crucible (6), and the bottom penetrates through the stainless steel base (21) and is fixed and sealed by the stainless steel gland (22) and the sealing ring (23); the upper top cover (5) cooperates with the top boss of the experimental section cylinder (3) and is sealed by a rubber ring; the upper part of the crucible (6) is an annular container, and the simulated working fluid is placed in the crucible (6); a circular through hole is opened at the bottom of the crucible (6) to release the simulated working fluid into the rod bundle channel (4); a sealing plug (7) is plugged on the circular through hole of the crucible (6) to control the loading and release of the simulated working fluid; the high-speed camera (8) is supported and fixed by a tripod and horizontally shoots the flow of the simulated working fluid in the rod bundle channel (4); this experimental device also includes a supporting simulated working fluid preparation system (9).

2. The experimental device for the continuous phase flow resistance characteristics in the rod bundle channel of a nuclear reactor according to claim 1, wherein: The experimental section cylinder (3) is a square sleeve (33), and the upper top cover (5) is square and cooperates with the top boss of the square sleeve (33).

3. The experimental device for the continuous-phase flow resistance characteristics in the nuclear reactor rod bundle channel according to claim 2, characterized in that: The square sleeve (33) is made of acrylic glass as the processing material, which is convenient for observing the flow of the simulated working fluid in the internal rod bundle channel through the high-speed camera (8).

4. The experimental device for the continuous-phase flow resistance characteristics in the nuclear reactor rod bundle channel according to claim 1, wherein: The simulation rods of the rod bundle channel (4) are made of Zr-4 alloy material as the processing material to simulate the surface properties of the cladding of a nuclear reactor.

5. The experimental device for the continuous phase flow resistance characteristics in the nuclear reactor rod bundle channel according to claim 1, characterized in that: The simulated working fluid preparation system (9) includes glycerol, an ultrapure water machine, a beaker, a high-precision electronic balance and a dropper; deionized water is prepared by the ultrapure water machine, and glycerol aqueous solutions with different mass fractions are prepared by the beaker, the high-precision electronic balance and the dropper. Different mass fractions of glycerol aqueous solutions are used to simulate liquids with different viscosities as the simulated working fluid, and the viscosity range of the simulated working fluid is 0.1-1 Pa·s.

6. The experimental device for the continuous-phase flow resistance characteristics in the nuclear reactor rod bundle channel according to claim 1, wherein: The bottom periphery of the described stainless-steel gland (22) is provided with four through holes and is connected to the stainless-steel base (21) through four bolts; four through holes are opened in the middle of the stainless-steel gland (22), and the simulated rod bundles of the rod bundle channel (4) penetrate through these through holes; there is a boss at the top of the stainless-steel gland (22) for pressing the sealing ring (23) in the groove of the stainless-steel base (21) to achieve axial sealing and fixing of the rod bundle channel (4).

7. The experimental device for the continuous phase flow resistance characteristics in the nuclear reactor rod bundle channel according to claim 1, characterized in that: Four special-shaped through holes are opened at the four corners of the described upper top cover (5) and are connected to the atmosphere to prevent the chemical working medium in the crucible (6) from being unable to be released into the rod bundle channel (4) through the circular through hole due to excessive pressure in the gas flow channel.

8. The experimental device for the continuous phase flow resistance characteristics in the nuclear reactor rod bundle channel according to claim 1, characterized in that: The bottom of the described crucible (6) is a two-stage boss. The first-stage boss is placed on the upper top cover (5), and the second-stage boss is inserted into the gas flow channel of the experimental section cylinder (3) through the circular through hole of the upper top cover (5). Four grooves are dug at the bottom of the second-stage boss for fixing the tops of the simulated rods of the rod bundle channel (4).

9. The experimental method of the experimental device for the continuous phase flow resistance characteristics in the nuclear reactor rod bundle channel according to any one of claims 1 to 8, characterized in that: The described experimental method is realized through the following steps: Before the experiment starts, all valves are kept closed; the surface of the simulated rod bundle of the rod bundle channel (4) is cleaned with alcohol and dried; the sealing plug (7) is tightly plugged into the through hole at the bottom of the crucible (6), and after preparing glycerol aqueous solutions with different mass fractions by using the beaker, high-precision electronic balance and rubber head dropper of the chemical working medium preparation system (9), a preset volume of glycerol aqueous solution is poured into the crucible (6); the focal length, height and distance of the high-speed camera (8) are adjusted and it is adjusted to be horizontal. When studying the wall friction resistance of the continuous phase in the rod bundle channel of the nuclear reactor, the high-speed camera (8) is turned on; the sealing plug (7) is vertically pulled out. When all the chemical working medium in the crucible (6) flows into the bottom of the rod bundle channel (4), the experiment is stopped, the high-speed camera (8) is turned off, and the wall friction resistance characteristics of the continuous phase in the rod bundle channel of the nuclear reactor are studied through the photographed flow process. When conducting the research on the friction resistance of the continuous-phase gas in the rod bundle channel of a nuclear reactor, open the valve (101) of the gas supply system (1), monitor the gas flow rate and pressure through the flowmeter (201) and the pressure gauge (301), and the gas flow rate range is 0 - 20 m 3 / h. Adjust the valve (101) to the preset gas flow rate and pressure; turn on the high-speed camera (8); vertically pull out the sealing plug (7), and stop the experiment when all the molten chemical working fluid in the crucible (6) flows into the bottom of the rod bundle channel (4). Then turn off the high-speed camera (8), and study the friction resistance characteristics of the continuous-phase gas in the rod bundle channel of the nuclear reactor through the captured flow process.

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