Reactor Core Heat Transfer Test Device

Abstract

The present invention discloses a reactor core heat exchange test device, which includes a test body. The test body includes an internal component and an external component. The internal component includes a flow channel and a core rod bundle. The core rod bundle is arranged in the flow channel and extends along the extension direction of the flow channel. The core rod bundle is a heating rod. The external component includes an upper shell, a core shell and a lower shell which are connected in sequence. The upper shell has an upper chamber, the lower shell has a lower chamber, the inner cavity of the core shell is communicated with the upper chamber and the lower chamber, the core shell is sleeved on the flow channel, and the upper end of the core rod bundle extends out of the upper chamber for connecting a power supply. The reactor core heat exchange test device according to the embodiment of the present invention has high structural strength and high test accuracy, can reproduce the geometric structure of the pressurized water reactor core to the greatest extent, and the test data obtained is closer to the actual situation of the core under the accident conditions of the prototype power station.

Description

Technical Field

[0001] The present invention relates to the technical field of nuclear power plants, and in particular, to a reactor core heat exchange test device. Background Art

[0002] With the development of nuclear power, higher requirements are put forward for the thermal-hydraulic and structural optimization design of nuclear reactor cores. The fuel assembly is the main component of the reactor core. The fuel assembly includes fuel rods and spacer grids. The fuel rods are usually arranged in a square rod bundle structure, and the spacer grids are arranged at different positions in the axial direction of the rod bundle structure to position the fuel rods. The coolant flows through the rod bundle area to cool the fuel rods and remove decay heat.

[0003] The flow channels of the rod bundle have geometric complexity, and at the same time, heat and mass transfer phenomena can occur between the rod sub-channels through the rod gaps. Therefore, the flow and heat transfer characteristics of the coolant in the rod bundle channels are more complex than those in simple channels. In addition, due to the presence of the grids, the flow field downstream of the rod bundle channel grids is prone to strong mixing, thereby enhancing the heat transfer downstream of the grids and making the flow and heat transfer characteristics of the rod bundle channels more complex.

[0004] The thermal-hydraulic performance of the rod bundle channels directly affects the safety, reliability and economy of nuclear power plants. Although the pressurized water reactor is a single-phase flow under normal operating conditions, a certain degree of boiling is usually allowed when increasing the thermal output power. In addition, boiling phenomena also occur in other accidents such as loss of coolant accidents in pressurized water reactors. How to ensure that the fuel cladding temperature is lower than the safety limit even in the case of a loss of coolant accident in the primary coolant system is one of the main tasks of the reactor thermal-hydraulic safety design. Therefore, it is necessary to conduct research on the core heat exchange performance under accidents, and then support the design improvement and the verification of safety analysis software. However, it is difficult to conduct such research on prototype reactors, resulting in difficulties in conducting tests on the core heat exchange performance under accidents. Summary of the Invention

[0005] The present invention aims to solve at least one of the technical problems in the related art to some extent.

[0006] To this end, an embodiment of the present invention provides a reactor core heat exchange test device.

[0007] The reactor core heat exchange test device according to the embodiment of the present invention includes a test body, and the test body includes:

[0008] Internal components, the internal components include flow channels and a core rod bundle, the core rod bundle is arranged in the flow channels and extends along the extension direction of the flow channels, and the core rod bundle is a heating rod;

[0009] External component, the external component includes an upper shell, a core shell and a lower shell which are connected in sequence. The upper shell has an upper chamber, the lower shell has a lower chamber, the inner cavity of the core shell communicates with the upper chamber and the lower chamber, the core shell is sleeved on the flow channel, and the upper end of the core rod bundle extends out of the upper chamber for connecting a power source.

[0010] In the reactor core heat transfer test device according to the embodiment of the present invention, by sleeving a core shell outside the flow channel to form a double-layer structure, the pressure resistance of the test body is improved. The core rod bundle is an electric heating rod, and the upper end of the core rod bundle is connected to a power source to heat the core rod bundle, ensuring that the test data is close to the real test data of the prototype nuclear power plant and improving the accuracy of the test. Moreover, the electric heating rod is easy to obtain and easy to operate. In addition, the structure of the test body is simple, reducing the test cost.

[0011] In some embodiments, the test body further includes a pressure balance pipe. One end of the pressure balance pipe is arranged on the core shell and communicates with the upper chamber, and the other end of the pressure balance pipe extends in a direction away from the core shell.

[0012] In some embodiments, the test body further includes a sleeve, a pressure guiding pipe and a ferrule. The sleeve is arranged on the core shell and communicates with the inner cavity of the core shell. One end of the pressure guiding pipe is connected to the flow channel, and the other end of the pressure guiding pipe extends out of the sleeve. The ferrule is arranged on the sleeve, and the ferrule seals and connects the sleeve and the pressure guiding pipe.

[0013] In some embodiments, the test body further includes a clamp. The clamp is sleeved on the flow channel.

[0014] In some embodiments, there are multiple clamps, and the multiple clamps are arranged at intervals along the axial direction of the flow channel.

[0015] In some embodiments, the test body further includes a support member. The support member is arranged between two adjacent clamps and is connected to the clamps. The support member is in an arc shape protruding away from the flow channel.

[0016] In some embodiments, the upper shell further has a gas-liquid mixture inlet, a subcooled water inlet and a gas-liquid mixture outlet that communicate with the upper chamber. The gas-liquid mixture inlet and the gas-liquid mixture outlet are arranged opposite to each other.

[0017] In some embodiments, the test body further includes a water distributor and a support plate. The water distributor is arranged in the upper chamber, and the support plate is arranged at the lower end of the flow channel to support the lower end of the core rod bundle.

[0018] In some embodiments, the lower housing further has a lower pipe orifice and a thermocouple penetrator that communicate with the lower chamber. The lower pipe orifice is used to discharge the gas-liquid mixture or inject cooling water, and the thermocouple penetrator is for threading a thermocouple wire bundle for measuring the temperature of the flow channel wall surface.

[0019] In some embodiments, the reactor core heat transfer test device further includes a test bench, an upper tower hoop, and a lower tower hoop. The upper tower hoop is provided at the upper end of the test body to connect the upper end of the test body to the test bench, and the lower tower hoop is detachably provided at the lower end of the test body to connect the lower end of the test body to the test bench. Brief Description of the Drawings

[0020] Figure 1 is an overall schematic diagram of the reactor core heat transfer test device according to an embodiment of the present invention.

[0021] Figure 2 is a schematic diagram of a partial structure of the reactor core heat transfer test device according to an embodiment of the present invention.

[0022] Figure 3 is Figure 2 an enlarged schematic diagram of part A in

[0023] Figure 4 is a sectional view of the upper structure of the reactor core heat transfer test device according to an embodiment of the present invention.

[0024] Figure 5 is a sectional view of the lower structure of the reactor core heat transfer test device according to an embodiment of the present invention.

[0025] Reference Numerals: 100, test body; 200, upper tower hoop; 300, lower tower hoop; 1, internal component; 11, flow channel; 12, core rod bundle; 2, external component; 21, upper housing; 211, upper chamber; 212, gas-liquid mixture inlet; 213, subcooled water inlet; 214, gas-liquid mixture outlet; 215, upper flange cover; 22, core housing; 23, lower housing; 231, lower chamber; 232, lower pipe orifice; 233, thermocouple penetrator; 234, lower flange cover; 3, pressure balance pipe; 41, sleeve; 42, pressure guiding pipe; 5, ferrule; 6, clamp; 7, support member; 8, water distributor; 9, support plate. Detailed Description of the Embodiments

[0026] The embodiments of the present invention will be described in detail below. The examples of the embodiments are shown in the drawings. The embodiments described below with reference to the drawings are exemplary and are intended to explain the present invention and should not be construed as limiting the present invention.

[0027] As Figures 1-5As shown in the figure, the reactor core heat transfer test device of the embodiment of the present invention includes a test body 100, and the test body 100 includes an internal member 1 and an external member 2. The internal member 1 includes a flow channel 11 and a core rod bundle 12. The core rod bundle 12 is arranged in the flow channel 11 and extends along the extension direction of the flow channel 11. The upper end of the core rod bundle 12 extends out of the upper end of the flow channel 11. The core rod bundle 12 is a heating rod, preferably an electric heating rod, to simulate the reactor core, and the length of the heating section of the electric heating rod is the same as the length of the real core heating section. A large number of thermocouple rods are arranged on the wall surface of the core rod bundle 12 to monitor the wall temperature and provide data for core heat transfer research. Specifically, the cross-sectional area of the flow channel 11 is square.

[0028] The external member 2 includes an upper shell 21, a core shell 22, and a lower shell 23 that are connected in sequence. The upper shell 21 has an upper chamber 211, the lower shell 23 has a lower chamber 231, the inner cavity of the core shell 22 communicates with the upper chamber 211 and the lower chamber 231, the core shell 22 is sleeved on the flow channel 11, and the upper end of the core rod bundle 12 extends out of the upper chamber 211 for connecting a power supply externally. Specifically, the upper end of the core rod bundle 12 is connected to a DC power supply.

[0029] For the reactor core heat transfer test device of the embodiment of the present invention, by sleeving the core shell 22 outside the flow channel 11 to form a double-layer structure, the pressure resistance of the test body 100 is improved. The core rod bundle 12 is an electric heating rod, and the upper end of the core rod bundle 12 is connected to a power supply to heat the core rod bundle 12, ensuring that the test data is close to the real test data of the prototype nuclear power plant and improving the accuracy of the test. Moreover, the electric heating rod is easy to obtain and operate. In addition, the structure of the test body 100 is simple, reducing the test cost.

[0030] Specifically, the flow channel 11 is formed by splicing four stainless steel plates. First, three of the stainless steel plates are welded, and the last stainless steel plate is connected by screws. A sealing gasket (not shown) is arranged on the inner wall surface of the flow channel 11. Preferably, the sealing gasket is a high-temperature resistant sealing gasket made of SF300 material to improve the sealing performance and prevent the liquid in the flow channel 11 from leaking into the annular cavity between the flow channel 11 and the core shell 22.

[0031] Specifically, the test body 100 further includes a spacer grid (not shown). The spacer grid uses a positioning grid that is the same as the typical grid element of the prototype grid to position the core rod bundle 12. The spacer grid is sleeved on the core rod bundle 12 to limit the core rod bundle 12 and ensure the stability of the structure of the core rod bundle 12. There is at least one spacer grid, and at least one spacer grid is arranged at intervals along the extension direction of the core rod bundle 12.

[0032] In some embodiments, the test body 100 further includes a pressure balance pipe 3. One end of the pressure balance pipe 3 is provided on the core housing 22 and communicates with the upper chamber 211, and the other end of the pressure balance pipe 3 extends in a direction away from the core housing 22.

[0033] Specifically, the pressure balance pipe 3 is located at the upper end of the core housing 22 and communicates with the upper chamber 211 through an external pipeline to eliminate the pressure difference between the flow channel 11 and the core housing 22 and prevent the unpressurized flow channel 11 in the design from being damaged by an excessive pressure difference.

[0034] In some embodiments, the test body 100 further includes a sleeve 41, a pressure guiding pipe 42, and a ferrule 5. The sleeve 41 is provided on the core housing 22 and communicates with the inner cavity of the core housing 22. One end of the pressure guiding pipe 42 is connected to the flow channel 11, and the other end of the pressure guiding pipe 42 extends out of the sleeve 41. The pressure guiding pipe 42 is used to measure the pressure and pressure difference in the flow channel 11. The ferrule 5 is provided on the sleeve 41, and the ferrule 5 seals and connects the sleeve 41 and the pressure guiding pipe 42.

[0035] Specifically, there are multiple sleeves 41, and the multiple sleeves 41 are arranged at intervals along the axial direction of the core housing 22. There are multiple pressure guiding pipes 42, and the multiple pressure guiding pipes 42 are arranged at intervals along the axial direction of the flow channel 11, and the multiple pressure guiding pipes 42 correspond to the multiple sleeves 41 one by one. The sleeve 41 is used to lead out the pressure guiding pipe 42 provided on the flow channel 11. There are also multiple ferrules 5, and the multiple ferrules 5 correspond to the multiple sleeves 41 one by one to ensure the sealing performance between the pressure guiding pipe 42 and the sleeve 41.

[0036] In some embodiments, the test body 100 further includes a clamp 6, and the clamp 6 is sleeved on the flow channel 11. Specifically, the flow channel 11 is designed to be relatively long and have a small wall thickness. The clamp 6 is sleeved on the flow channel 11 to increase the structural strength of the flow channel 11 and prevent the flow channel 11 from deforming during the hoisting process.

[0037] In some embodiments, there are multiple clamps 6, and the multiple clamps 6 are arranged at intervals along the axial direction of the flow channel 11, further increasing the structural strength of the flow channel 11 and ensuring the structural stability of the flow channel 11 during the movement process.

[0038] In some embodiments, the test body 100 further includes a support member 7. The support member 7 is provided between two adjacent clamps 6 and is connected to the clamps 6. The support member 7 is in an arc shape protruding away from the flow channel 11.

[0039] Specifically, there are multiple support members 7. The multiple support members 7 are divided into multiple groups, and the multiple groups of support members 7 are arranged at intervals along the axial direction of the flow channel 11. Each group includes multiple support members 7, and the multiple support members 7 in each group are arranged at intervals along the circumferential direction of the flow channel 11. One end of the support member 7 is connected to one of the clamps 6, and the other end of the support member 7 is connected to an adjacent other clamp 6. The convex arc surface of the support member 7 contacts the inner wall surface of the core housing 22, preventing the flow channel 11 from undergoing horizontal displacement within the inner cavity of the core housing 22, ensuring the stability of the installation of the flow channel 11. Moreover, it also avoids the collision between the flow channel 11 and the inner wall surface of the core housing 22, ensuring the structural stability of the flow channel 11.

[0040] In some embodiments, the upper housing 21 further has a gas-liquid mixture inlet 212, a subcooled water inlet 213, and a gas-liquid mixture outlet 214 that communicate with the upper chamber 211, for the inflow and outflow of the working medium during different test stages. Among them, the gas-liquid mixture inlet 212 and the gas-liquid mixture outlet 214 are arranged opposite to each other.

[0041] Specifically, an upper flange cover 215 is connected to the top of the upper housing 21 for sealing. The upper end of the core rod bundle 12 extends out through the upper flange cover 215, and a graphite compression seal is provided between the core rod bundle 12 and the upper flange cover 215. In order to increase the sealing space and ensure the strength of the upper flange cover 215, the rod pitch of the core rod bundle 12 is enlarged in the upper chamber 211.

[0042] In some embodiments, the test body 100 further includes a water distributor 8 and a support plate 9. The water distributor 8 is arranged in the upper chamber 211 to make the fluid entering the upper chamber 211 evenly distributed in the upper chamber 211. The support plate 9 is arranged at the lower end of the flow channel 11 and supports the lower end of the core rod bundle 12.

[0043] In some embodiments, the lower housing 23 further has a lower pipe orifice 232 and a thermocouple penetration 233 that communicate with the lower chamber 231. The lower pipe orifice 232 is used to discharge the gas-liquid mixture or inject cooling water. The thermocouple penetration 233 is arranged on the bottom surface of the lower housing 23 and communicates with the lower chamber 231. A thermocouple wire bundle for measuring the wall temperature of the flow channel 11 is arranged inside the thermocouple penetration 233.

[0044] Specifically, the lower housing 23 and the lower end of the flow channel 11 are hermetically connected through a lower flange cover 234. The support plate 9 is arranged between the top of the lower housing 23 and the lower end of the flow channel 11 to support the lower end of the core rod bundle 12 inside the flow channel 11. The lower pipe orifice 232 is arranged on the bottom surface of the lower housing 23 and can be used as the outlet of the gas-liquid mixture in the spray discharge or reflooding test or the injection port of the cooling water in the reflooding test.

[0045] It is understandable that the reactor core heat transfer test device according to the embodiments of the present invention is provided with a rich injection nozzle and measuring instruments, so that the test device can study the core heat transfer phenomena in various stages such as high, medium and low pressure blowdown, refilling, reflooding and long-term cooling during a large break accident, and has perfect functions.

[0046] In some embodiments, the reactor core heat transfer test device further includes a test bench (not shown), an upper tower hoop 200 and a lower tower hoop 300. The upper tower hoop 200 is welded to the upper end of the test body 100 to connect the upper end of the test body 100 with the test bench. The lower tower hoop 300 is detachably connected to the lower end of the test body 100 to connect the lower end of the test body 100 with the test bench. The lower tower hoop 300 can limit the displacement of the test body 100 in the horizontal direction without restricting its displacement in the vertical direction, which can effectively avoid the test body 100 from bearing excessive stress due to thermal expansion and contraction during the temperature rise and fall process, and improve the safety of the test device.

[0047] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by terms such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0048] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, "a plurality" means at least two, such as two, three, etc., unless otherwise specifically and clearly defined.

[0049] In the present invention, unless otherwise clearly specified and limited, the terms such as "installation", "connection", "connection", "fixation" and other terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection, an electrical connection or communication with each other; it can be directly connected, or indirectly connected through an intermediate medium, and can be the communication inside two elements or the interaction relationship between two elements, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0050] In the present invention, unless otherwise clearly specified or limited, a first feature being "on" or "under" a second feature may mean that the first and second features are in direct contact, or the first and second features are indirectly in contact via an intermediate medium. Also, a first feature being "above", "over" and "on top of" a second feature may mean that the first feature is directly above or obliquely above the second feature, or merely indicates that the horizontal height of the first feature is higher than that of the second feature. A first feature being "under", "below" and "beneath" a second feature may mean that the first feature is directly below or obliquely below the second feature, or merely indicates that the horizontal height of the first feature is less than that of the second feature.

[0051] In the present invention, the terms "an embodiment", "some embodiments", "an example", "a specific example", or "some examples", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, without contradiction, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0052] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. A reactor core heat exchange test device, characterized in that, Comprising a test body (100), the test body (100) includes: An internal component (1), the internal component (1) includes a flow channel (11) and a core rod bundle (12), the core rod bundle (12) is arranged in the flow channel (11) and extends along the extension direction of the flow channel (11), and the core rod bundle (12) is a heating rod; An external component (2), the external component (2) includes an upper shell (21), a core shell (22) and a lower shell (23) connected in sequence, the upper shell (21) has an upper chamber (211), the lower shell (23) has a lower chamber (231), the inner cavity of the core shell (22) is communicated with the upper chamber (211) and the lower chamber (231), the core shell (22) is sleeved on the flow channel (11), and the upper end of the core rod bundle (12) extends out of the upper chamber (211) for connecting a power supply; The test body (100) further includes a pressure balance pipe (3), one end of the pressure balance pipe (3) is arranged on the core shell (22) and communicated with the upper chamber (211) to eliminate the pressure difference between the flow channel and the core shell, and the other end of the pressure balance pipe (3) extends in a direction away from the core shell (22); The test body (100) further includes a clamp (6), and the clamp (6) is sleeved on the flow channel (11); The test body (100) further includes a support member (7), the support member (7) is arranged between two adjacent clamps (6) and connected to the clamp (6), and the support member (7) is in an arc shape protruding away from the flow channel (11).

2. The reactor core heat exchange test device according to claim 1, wherein The test body (100) further includes a sleeve (41), a pressure guiding pipe (42) and a ferrule (5), the sleeve (41) is arranged on the core shell (22) and communicated with the inner cavity of the core shell (22), one end of the pressure guiding pipe (42) is connected to the flow channel (11), the other end of the pressure guiding pipe (42) extends out of the sleeve (41), the ferrule (5) is arranged on the sleeve (41), and the ferrule (5) seals and connects the sleeve (41) and the pressure guiding pipe (42).

3. The reactor core heat exchange test device according to claim 1, characterized in that, There are multiple clamps (6), and the multiple clamps (6) are arranged at intervals along the axial direction of the flow channel (11).

4. The reactor core heat transfer test device according to claim 1, wherein The upper shell (21) further has a gas-liquid mixture inlet (212), a subcooled water inlet (213) and a gas-liquid mixture outlet (214) communicated with the upper chamber (211), and the gas-liquid mixture inlet (212) and the gas-liquid mixture outlet (214) are arranged opposite to each other.

5. The reactor core heat transfer test device according to claim 4, characterized in that, The test body (100) further includes a water distributor (8) and a support plate (9), the water distributor (8) is arranged in the upper chamber (211), and the support plate (9) is arranged at the lower end of the flow channel (11) to support the lower end of the core rod bundle (12).

6. The reactor core heat transfer test device according to claim 1, wherein The lower housing (23) further has a lower pipe orifice (232) and a thermocouple penetrator (233) that communicate with the lower chamber (231). The lower pipe orifice (232) is used for discharging the gas-liquid mixture or injecting cooling water, and a thermocouple wire bundle (234) for measuring the wall temperature of the flow channel (11) is disposed inside the thermocouple penetrator (233).

7. The reactor core heat exchange test device according to claim 1, characterized in that, It further includes a test bench, an upper tower hoop (200), and a lower tower hoop (300). The upper tower hoop (200) is provided at the upper end of the test body (100) to connect the upper end of the test body (100) to the test bench, and the lower tower hoop (300) is detachably provided at the lower end of the test body (100) to connect the lower end of the test body (100) to the test bench.

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