Lower reactor internals and supercritical water cooled reactor

Abstract

The invention provides a lower reactor internal and a supercritical water cooled reactor, the lower reactor internal comprises a hanging basket cylinder and a reactor core lower plate, the top of the hanging basket cylinder is connected with an upper reactor internal flange, the outer side of the hanging basket cylinder and the inner side of a pressure vessel form an annular cavity, and a fast heating fuel isolation cylinder is also arranged in the hanging basket cylinder; the reactor core lower plate is mounted at the bottom of the hanging basket barrel, one end of the fast-heating fuel isolation barrel is mounted on the reactor core lower plate, and at least one fast neutron fuel assembly located in the fast-heating fuel isolation barrel and at least one thermal neutron fuel assembly located outside the fast-heating fuel isolation barrel are arranged on the reactor core lower plate; a circulation cavity is formed in the middle of the reactor core lower plate, a lower cavity is formed between the bottom of the reactor core lower plate and the pressure container, and one end of the thermal neutron fuel assembly and one end of the fast neutron fuel assembly are communicated with the circulation cavity and the lower cavity respectively. According to the lower reactor internals, the circulation cavity stirs two paths of coolants entering the fast neutron fuel assembly, the flow is reasonably distributed, and the flow distribution uniformity is improved.

Description

Technical Field

[0001] The invention relates to the technical field of supercritical water-cooled reactor flow channel design, and in particular to a lower reactor internal component and a supercritical water-cooled reactor. Background Art

[0002] The supercritical water-cooled reactor is the only water-cooled reactor among the six reactor types identified by the International Forum on Generation IV Nuclear Energy Systems. Currently, research on reactor structures with single-flow, dual-flow, and triple-flow coolants has been carried out.

[0003] The function of the lower internals structure in a supercritical water-cooled reactor is to provide support, positioning and guidance for the fuel assembly and related components, guide the flow of a flow of coolant through the core, and reasonably distribute the flow; provide radiation shielding for the reactor pressure vessel to reduce the core radiation damage it suffers; and guide the coolant into the core under the hypothetical loss of coolant accident. However, the lower internals of the current reactor type cannot separate the coolant entering the thermal neutron fuel and the fast neutron fuel, and cannot meet the uniformity requirements of the above fuel assembly flow distribution.

[0004] Based on this, the inventor of the present application proposes a lower reactor internal component and a supercritical water-cooled reactor in order to solve the above technical problems. Summary of the invention

[0005] The technical problem to be solved by the present invention is to overcome the defect in the prior art that the lower core plate cannot meet the flow distribution uniformity requirement of a supercritical water-cooled reactor, and to provide a lower core internal component and a supercritical water-cooled reactor.

[0006] The present invention solves the above technical problems through the following technical solutions:

[0007] The present invention provides a lower internal component, which is characterized by comprising:

[0008] The top of the hanging basket cylinder is connected to the flange of the upper internal component of the pile, the outer side of the hanging basket cylinder and the inner side of the pressure vessel form an annular cavity, and the hanging basket cylinder is also provided with a fast-heating fuel isolation cylinder;

[0009] The core lower plate is installed at the bottom of the hanging basket cylinder, one end of the fast thermal fuel isolation tube is installed on the core lower plate, and the core lower plate is provided with at least one fast neutron fuel assembly located in the fast thermal fuel isolation tube and at least one thermal neutron fuel assembly located outside the fast thermal fuel isolation tube; wherein,

[0010] A flow cavity is opened in the middle of the core lower plate, a lower chamber is formed between the bottom of the core lower plate and the pressure vessel, and one end of the thermal neutron fuel assembly and the fast neutron fuel assembly are respectively connected to the flow cavity and the lower chamber.

[0011] According to one embodiment of the present invention, a first flow hole and at least one second flow hole are provided at the bottom of the thermal neutron fuel assembly, wherein the first flow hole is provided at one end of the thermal neutron fuel assembly extending to the lower chamber and communicates with the lower chamber;

[0012] At least one of the second flow holes is located in the flow cavity;

[0013] The bottom of the fast neutron fuel assembly is provided with a first inlet and at least one second inlet, wherein the first inlet is provided at one end of the fast neutron fuel assembly extending to the lower chamber, and the at least one second inlet is located in the flow chamber.

[0014] According to one embodiment of the present invention, the number of the second flow holes is at least two, and at least two of the second flow holes are arranged at intervals around the circumference of the thermal neutron fuel assembly;

[0015] The number of the second inlets is at least two, and at least two of the second inlets are spaced apart around the circumference of the fast neutron fuel assembly.

[0016] According to one embodiment of the present invention, at least two third flow holes are further provided at the bottom of the core lower plate, and the third flow holes are communicated with the flow cavity;

[0017] At least two of the third flow holes are arranged at intervals along a direction from the thermal neutron fuel assembly to the fast neutron fuel assembly.

[0018] According to one embodiment of the present invention, one end of the fast-heat fuel isolation tube is welded to the core lower plate.

[0019] According to one embodiment of the present invention, an isolation ring is further provided on the outside of the hanging basket cylinder, the isolation ring is located in the ring cavity and the two ends of the isolation ring are respectively connected to the outer wall of the hanging basket cylinder and the inner wall of the pressure vessel, and the isolation ring is used to separate the lower chamber and the inlet connecting pipe arranged on the pressure vessel.

[0020] According to an embodiment of the present invention, a flow gap is provided on the isolation ring, and at least part of the coolant flowing in through the inlet pipe flows to the lower chamber through the flow gap.

[0021] According to one embodiment of the present invention, the core lower plate is provided with at least one stirring mechanism in the flow cavity, and the stirring mechanism is used to stir the coolant flowing out of the thermal neutron fuel assembly before flowing into the fast neutron fuel assembly.

[0022] According to one embodiment of the present invention, the turbulence mechanism is a spoiler block, and the spoiler block is arranged on the top wall of the flow chamber;

[0023] The number of the spoiler blocks is at least two, and at least two of the spoiler blocks are arranged at intervals along the radial direction of the lower core plate.

[0024] The present invention also provides a supercritical water-cooled reactor, which is characterized in that it includes the lower reactor internals as described above.

[0025] The positive and progressive effects of the present invention are:

[0026] The lower internal component of the present invention has a flow cavity in the middle of the lower core plate. The coolant flowing out of the thermal neutron fuel assembly and the coolant in the lower chamber are mixed in the flow cavity and then flow into the fast neutron fuel assembly. The flow cavity can mix the coolants of the two paths and reasonably distribute the flow, thereby improving the uniformity of flow distribution and reducing the resistance to the coolant, simplifying the on-site installation process. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The above and other features, properties and advantages of the present invention will become more apparent through the following description in conjunction with the accompanying drawings and embodiments, in which:

[0028] Figure 1 It is a schematic diagram of the structure of the supercritical water-cooled reactor of the present invention;

[0029] Figure 2 It is a schematic structural diagram of the lower internal components of the present invention;

[0030] Figure 3 for Figure 2 Schematic diagram of flow channel distribution at the lower plate of the middle core;

[0031] Figure 4 for Figure 2 Schematic diagram of the structure of the lower core plate;

[0032] Figure 5 for Figure 4 A cross-sectional view of an embodiment of a lower core plate in FIG.

[0033] Figure 6 for Figure 4 A cross-sectional view of another embodiment of the lower core plate in FIG.

[0034] Figure 7 It is a structural schematic diagram of another embodiment of the lower internal component of the present invention;

[0035] Figure 8 for Figure 7 Schematic diagram of flow channel distribution at the lower plate of the middle core;

[0036] Fig. 9 for Figure 7 Schematic diagram of the structure of the lower plate of the middle core;

[0037] Fig.10 for Figure 7 Cross-section of the lower core plate.

[0038] 1. Basket cylinder; 11. Quick-heat fuel isolation cylinder; 12. Isolation ring; 121. Flow gap;

[0039] 2. Top cover;

[0040] 3. pressure vessel; 31. annular cavity; 32. lower chamber;

[0041] 4. lower core plate; 41. flow cavity; 42. third flow hole; 43. stirring mechanism;

[0042] 5. thermal neutron fuel assembly; 51. first flow hole; 52. second flow hole;

[0043] 6. Fast neutron fuel assembly; 61. First inlet; 62. Second inlet. DETAILED DESCRIPTION

[0044] The present invention is further described below in conjunction with specific embodiments and drawings. More details are elaborated in the following description to facilitate a full understanding of the present invention. However, the present invention can obviously be implemented in a variety of other ways different from the description herein. Those skilled in the art can make similar generalizations and deductions based on actual application situations without violating the connotation of the present invention. Therefore, the protection scope of the present invention should not be limited by the content of this specific embodiment.

[0045] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0046] Please refer to Figures 1 to 10 The present invention proposes a lower internal component, including a hanging basket cylinder 1 and a core lower plate 4, the top of the hanging basket cylinder 1 extends to the top cover 2 of the pressure vessel 3, the outer side of the hanging basket cylinder 1 and the inner side of the pressure vessel 3 form an annular cavity 31, and a fast thermal fuel isolation tube 11 is also provided in the hanging basket cylinder 1; the core lower plate 4 is installed at the bottom of the hanging basket cylinder 1, and one end of the fast thermal fuel isolation tube 11 is installed on the core lower plate 4, and at least one fast neutron fuel assembly 5 located in the fast thermal fuel isolation tube 11 and at least one thermal neutron fuel assembly 6 located outside the fast thermal fuel isolation tube 11 are provided on the core lower plate 4. Among them, a flow cavity 41 is opened in the middle of the core lower plate 4, and a lower chamber 32 is formed between the bottom of the core lower plate 4 and the pressure vessel 3, and one end of the thermal neutron fuel assembly 5 and the fast neutron fuel assembly 6 are respectively connected to the flow cavity 41 and the lower chamber 32.

[0047] The top of the basket cylinder 1 is connected to the upper internal component flange through a flange, for example, the top flange of the basket cylinder 1 is hung on the upper surface of the upper internal component flange and connected through a positioning piece. The fast thermal fuel isolation cylinder 11 in the basket cylinder 1 is used to separate the hot and cold coolants of the first and second processes. One end of the basket cylinder 1 is welded to the lower core plate 4. A plurality of fast neutron fuel assemblies 6 are located in the fast thermal fuel isolation cylinder 11, and a plurality of thermal neutron fuel assemblies 5 are located in the space between the outside of the fast thermal fuel isolation cylinder 11 and the basket cylinder 1.

[0048] Please refer to Figures 1 to 3 After the coolant flows into the pressure vessel 3 through the inlet pipe, the first-flow coolant flows from top to bottom through the hanging basket thermal neutron fuel assembly 5 to the flow chamber 41 and the lower chamber 32. The coolant in the flow chamber 41 and the lower chamber 32 is evenly mixed in the flow chamber 41 and then heated upward from the fast neutron fuel assembly 6 as the second-flow coolant, and finally discharged to the outside of the pressure vessel 3 from the outlet pipe.

[0049] A flow cavity 41 is provided in the core lower plate 4 so that the coolant flowing from the lower chamber 32 and the thermal neutron fuel assembly 5 into the flow cavity 41 can be agitated, so that the flow distribution of the coolant entering the fast neutron fuel assembly 6 is more uniform.

[0050] Please refer to Figures 3 to 5 A first flow hole 51 and at least one second flow hole 52 are provided at the bottom of the thermal neutron fuel assembly 5. The first flow hole 51 is provided at one end of the thermal neutron fuel assembly 5 extending to the lower chamber 32 and is connected to the lower chamber 32; the at least one second flow hole 52 is located in the flow cavity 41; a first inlet 61 and at least one second inlet 62 are provided at the bottom of the fast neutron fuel assembly 6. The first inlet 61 is provided at one end of the fast neutron fuel assembly 6 extending to the lower chamber 32, and the at least one second inlet 62 is located in the flow cavity 41.

[0051] That is, the thermal neutron fuel assembly 5 is hollow and has two flow channels at the bottom. Part of the coolant flowing out of the thermal neutron fuel assembly 5 flows to the lower chamber 32 through the first flow hole 51, and the other part of the coolant flows into the flow cavity 41 through the second flow hole 52. The coolant in the lower chamber 32 and the coolant in the flow cavity 41 are evenly mixed in the flow cavity 41 and then transported upward to the outlet pipe through the fast neutron fuel assembly 6.

[0052] Specifically, the number of the second flow holes 52 is at least two, and at least two second flow holes 52 are arranged at intervals around the circumference of the thermal neutron fuel assembly 5; the number of the second inlets 62 is at least two, and at least two second inlets 62 are arranged at intervals around the circumference of the fast neutron fuel assembly 6.

[0053] In order to improve the uniformity of the coolant flowing into the circulation cavity 41 through the thermal neutron fuel assembly 5 , a plurality of second circulation holes 52 are provided, and the plurality of second circulation holes 52 are evenly spaced around the circumference of the thermal neutron fuel assembly 5 .

[0054] Similarly, a plurality of second inlets 62 are provided around the circumference of the fast neutron fuel assembly 6 , thereby improving the uniformity of the coolant flowing into the fast neutron fuel assembly 6 .

[0055] Please continue to refer to Figure 4 and Figure 5 At least two third flow holes 42 are also provided at the bottom of the core lower plate 4 , and the third flow holes 42 are connected to the flow cavity 41 ; at least two third flow holes 42 are arranged at intervals along the direction from the thermal neutron fuel assembly 5 to the fast neutron fuel assembly 6 .

[0056] That is, the coolant in the lower chamber 32 flows into the fast neutron fuel assembly 6 through the first inlet 61, and at the same time, flows into the flow cavity 41 through the third flow hole 42 and converges with the coolant flowing out of the thermal neutron fuel assembly 5 in the flow cavity 41 and then further flows into the fast neutron fuel assembly 6 through the second inlet 62, thereby improving the uniformity of flow distribution.

[0057] Please refer to Figure 5 and Figure 6 The size and number of the third flow holes 42 can be adjusted according to actual needs and are not limited here.

[0058] It can be seen that one end of the fast thermal fuel isolation tube 11 is welded to the core lower plate 4. For example, the fast thermal fuel isolation tube 11 can be formed by welding a C-type plate and a W-type plate, and fixed to the upper surface of the core lower plate 4 by welding, and cooperate with the upper internal components to realize the separation of the thermal neutron fuel heat exchange area and the fast neutron fuel heat exchange area, thereby improving the comprehensive utilization rate of fuel heat.

[0059] Please continue to refer to Figure 2 and Figure 3 An isolation ring 12 is also provided on the outside of the hanging basket cylinder 1. The isolation ring 12 is located in the ring cavity 31 and the two ends of the isolation ring 12 are respectively connected to the outer wall of the hanging basket cylinder 1 and the inner wall of the pressure vessel 3. The isolation ring 12 is used to separate the lower chamber 32 and the inlet pipe arranged on the pressure vessel 3.

[0060] Furthermore, a flow gap 121 is provided on the isolation ring 12 , and at least a portion of the coolant flowing in through the inlet pipe flows to the lower chamber 32 through the flow gap 121 .

[0061] Specifically, one end of the isolation ring 12 is welded to the outer wall of the hanging basket cylinder 1, and the other end is abutted against the inner wall of the pressure vessel 3. Alternatively, the isolation ring 12 is divided into two parts, one of which is arranged on one side of the hanging basket cylinder 1, and the other is arranged on one side of the inner wall 3 of the pressure vessel, and the two cooperate to form a flow gap 121. The isolation ring 12 is used to divide the annular cavity 31 into two parts, and the upper part of the annular cavity 31 is connected to the inlet pipe of the pressure vessel 3, so that the low-temperature coolant can enter the thermal neutron fuel assembly 5 from the upper water flow hole of the hanging basket cylinder 1. The lower part of the annular cavity 31 is connected to the lower chamber 32, which is used to receive part of the coolant to cool the inner wall of the pressure vessel 3.

[0062] The flow gap 121 is provided on the isolation ring 12 so that part of the coolant can flow through the flow gap 121 through the lower part of the annular cavity 31 to reach the lower chamber 32, so that the inner wall of the pressure vessel 3 can be cooled by heat exchange to ensure that the temperature inside the pressure vessel 3 does not exceed the temperature it can withstand.

[0063] Moreover, an isolation ring 12 is provided on the outside of the hanging basket cylinder 1, and the flow velocity through the isolation ring 12 to the lower chamber 32 is lower, which is beneficial to reduce the flow-induced vibration influence of the lower internal components.

[0064] Please refer to Figures 7 to 10 The stirring mechanism 43 is a spoiler block, which is arranged on the top wall of the flow chamber 41; the number of the spoiler blocks is at least two, and at least two spoiler blocks are arranged at intervals along the radial direction of the lower plate 4 of the core.

[0065] Providing a turbulent block in the flow cavity 41 is beneficial to agitating the coolant in the flow cavity 41 , so that the flow of the coolant entering the fast neutron fuel assembly 6 is more uniform.

[0066] Specifically, the size and quantity of the spoiler blocks can be adjusted according to actual needs, for example, the sizes can be consistent (refer to Fig. 9 ) and are uniform in the flow chamber 41, or the size may be partially different (refer to Figure 8 ) can be randomly arranged in the flow cavity 41, and no limitation is made here.

[0067] The present invention also provides a supercritical water-cooled reactor, comprising the above-mentioned lower reactor internals.

[0068] The supercritical water-cooled reactor also includes an upper internal component located at the upper part of the hanging basket cylinder 1. The upper internal component and the lower internal component cooperate with each other to complete the design of the dual-flow channel.

[0069] Among them, the lower internal components are used to guide a flow of coolant through the core, and the core lower plate 4 adopts a double-layer plate structure and a flow cavity 41 is set in the middle, so that the coolant can be stirred at the inlet of the fast neutron fuel assembly 6 and the flow can be reasonably distributed. The structure of the core lower plate 4 is simpler, the flow distribution is more uniform, and the resistance of the coolant is small, which simplifies the on-site installation process.

[0070] Furthermore, an isolation ring 12 is provided on the outside of the hanging basket cylinder 1, and the flow velocity flowing through the isolation ring 12 to the lower chamber 32 is lower, thereby reducing the flow-induced vibration influence on the lower internal components.

[0071] The core lower plate 4 constrains the position of the thermal neutron fuel assembly 5 and the fast neutron fuel assembly 6 through holes, eliminates the fuel assembly positioning pins, reduces the number of fasteners, and further reduces the risk of fasteners of the internal components falling off.

[0072] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "install", "connect", "connect", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can also be a mechanical connection. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0073] The present application uses specific words to describe the embodiments of the present application. For example, "one embodiment", "an embodiment", and / or "some embodiments" refer to a certain feature, structure or characteristic related to at least one embodiment of the present application. Therefore, it should be emphasized and noted that "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or multiple times in different positions in this specification does not necessarily refer to the same embodiment. In addition, some features, structures or characteristics in one or more embodiments of the present application can be appropriately combined.

[0074] Although the present invention is disclosed as above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications without departing from the spirit and scope of the present invention. Therefore, any modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope defined by the claims of the present invention.

Claims

1. A lower internal component, characterized in that: include: The top of the hanging basket cylinder is connected to the flange of the upper internal component of the pile, the outer side of the hanging basket cylinder and the inner side of the pressure vessel form an annular cavity, and the hanging basket cylinder is also provided with a fast-heating fuel isolation cylinder; The core lower plate is installed at the bottom of the hanging basket cylinder, one end of the fast thermal fuel isolation tube is installed on the core lower plate, and the core lower plate is provided with at least one fast neutron fuel assembly located in the fast thermal fuel isolation tube and at least one thermal neutron fuel assembly located outside the fast thermal fuel isolation tube; wherein, A flow cavity is opened in the middle of the core lower plate, a lower chamber is formed between the bottom of the core lower plate and the pressure vessel, and one end of the thermal neutron fuel assembly and the fast neutron fuel assembly are respectively connected to the flow cavity and the lower chamber.

2. The lower internals according to claim 1, characterized in that: A first flow hole and at least one second flow hole are provided at the bottom of the thermal neutron fuel assembly, wherein the first flow hole is provided at one end of the thermal neutron fuel assembly extending to the lower chamber and is in communication with the lower chamber; At least one of the second flow holes is located in the flow cavity; The bottom of the fast neutron fuel assembly is provided with a first inlet and at least one second inlet, wherein the first inlet is provided at one end of the fast neutron fuel assembly extending to the lower chamber, and the at least one second inlet is located in the flow chamber.

3. The lower internals according to claim 2, characterized in that: The number of the second flow holes is at least two, and at least two of the second flow holes are spaced apart around the circumference of the thermal neutron fuel assembly; The number of the second inlets is at least two, and at least two of the second inlets are spaced apart around the circumference of the fast neutron fuel assembly.

4. The lower internals according to claim 1, characterized in that: At least two third flow holes are also formed at the bottom of the core lower plate, and the third flow holes are connected to the flow cavity; At least two of the third flow holes are arranged at intervals along a direction from the thermal neutron fuel assembly to the fast neutron fuel assembly.

5. The lower internals according to claim 1, characterized in that: One end of the fast-heat fuel isolation tube is welded to the core lower plate.

6. The lower internals according to claim 1, characterized in that: An isolation ring is also provided on the outside of the hanging basket cylinder. The isolation ring is located in the ring cavity and the two ends of the isolation ring are respectively connected to the outer wall of the hanging basket cylinder and the inner wall of the pressure vessel. The isolation ring is used to separate the lower chamber and the inlet pipe provided on the pressure vessel.

7. The lower internals according to claim 6, characterized in that: The isolating ring is provided with a flow gap, and at least part of the coolant flowing in through the inlet pipe flows to the lower chamber through the flow gap.

8. The lower internals according to claim 1, characterized in that: The core lower plate is provided with at least one stirring mechanism in the flow cavity, and the stirring mechanism is used to stir the coolant flowing out of the thermal neutron fuel assembly before flowing into the fast neutron fuel assembly.

9. The lower internals according to claim 8, characterized in that: The stirring mechanism is a spoiler block, and the spoiler block is arranged on the top wall of the flow chamber; The number of the spoiler blocks is at least two, and at least two of the spoiler blocks are arranged at intervals along the radial direction of the lower core plate.

10. A supercritical water-cooled reactor, characterized in that: It comprises the lower internals as described in any one of claims 1 to 9.

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