Reactor core structure for improving passive self-flowing capacity

Abstract

The invention relates to the technical field of nuclear reactor structures, in particular to a reactor core structure capable of improving passive self-flowing capacity, which mainly comprises an upper seal head, a lower seal head and a barrel arranged between the upper seal head and the lower seal head, a plurality of fuel assembly sleeves are arranged between a limiting plate and a resistance adjusting plate, and the resistance adjusting plate is arranged between the limiting plate and the resistance adjusting plate. A resistance adjusting part is arranged at the joint of the resistance adjusting plate and the fuel assembly sleeve and is used for adjusting resistance of an inlet of the fuel assembly sleeve, flow distribution of the fuel assembly can be conveniently adjusted through the structure, a reactor core chlorophytum comosum and a descending annular cavity are omitted, 180-degree turning of coolant flowing is eliminated, and the flow distribution efficiency is improved. The flowing resistance of the coolant in and out of the reactor core is reduced. The combined action of the two can improve the natural circulation potential of the reactor so as to improve the self-flowing capacity of the reactor. Meanwhile, the in-reactor structure is greatly simplified, most of in-reactor components are omitted, the manufacturing difficulty and cost of the reactor core are reduced, and the total weight of the reactor core is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of nuclear reactor structures, and in particular to a core structure capable of improving passive self-flow capability. Background Art

[0002] The structure of a nuclear reactor includes the reactor core, control rods, coolant, pressure vessel, etc. The reactor core is the core area where nuclear fission reaction takes place, and the control rods control the reaction rate by adjusting the neutron absorption rate. The coolant is responsible for taking away the heat generated by the reaction and maintaining the safe operation of the reactor.

[0003] In order to improve the nuclear safety level of nuclear power plants, third-generation nuclear power plants, such as the Hualong One nuclear power plant independently developed by my country, generally introduce natural circulation to achieve the removal of residual heat from the core in the event of a power outage. Since natural circulation is an automatic physical process that does not rely on the drive of the main pump, it is called a passive self-flow heat transfer process.

[0004] Due to the complexity of the existing reactor structure, there is a problem of extremely large core flow resistance (accounting for more than 40% of the total resistance of a single loop). At the same time, the uneven distribution of core power leads to a large coolant enthalpy rise factor, which limits the improvement of the reactor's natural circulation capacity. As a result, it can only be used for passive residual heat removal under accident conditions and cannot be used for rated design conditions. Summary of the invention

[0005] The purpose of the present invention is to provide a core structure with improved passive self-flow capability to solve the above problems existing in the prior art.

[0006] The present invention is achieved through the following technical solutions:

[0007] A core structure for improving passive self-flowing capacity, comprising an upper head, a lower head and a cylinder arranged between the upper head and the lower head;

[0008] A limit plate is provided at one end of the cylinder body close to the upper end cap, and a resistance adjustment plate is provided at one end close to the lower end cap. A plurality of fuel assembly sleeves are provided between the limit plate and the resistance adjustment plate, and two ends of the fuel assembly sleeves are rotatably connected to the limit plate and the resistance adjustment plate respectively.

[0009] A resistance adjusting portion is provided at the connection between the resistance adjusting plate and the fuel assembly sleeve, and the resistance adjusting portion and the resistance adjusting plate are rotatably matched to adjust the resistance of the inlet of the fuel assembly sleeve.

[0010] Preferably, one end of the fuel assembly sleeve is provided with an outflow hole, and the other end is provided with a through-flow hole, the resistance adjustment part includes an assembly limiting groove opened on the resistance adjustment plate and a semicircular baffle plate arranged in the through-flow hole, the end of the fuel assembly sleeve with the semicircular baffle is located in the assembly limiting groove and rotates, and a plurality of through-flow holes are opened on the assembly limiting groove, and the coverage area of ​​the through-flow holes is smaller than the area of ​​the through-flow hole.

[0011] Preferably, a plurality of outflow holes are arranged around one end of the fuel assembly sleeve.

[0012] Preferably, a rotating tool is provided at one end of the fuel assembly sleeve close to the outflow hole.

[0013] Preferably, the limiting plate is provided with a plurality of limiting holes, and one end of the fuel assembly sleeve is located in the limiting hole and rotates.

[0014] Preferably, the limiting plate is also provided with a plurality of reflux holes.

[0015] Preferably, a plurality of first bolt holes are formed on the edge of the limiting plate, and the limiting plate is bolted to the cylinder through the first bolt holes.

[0016] Preferably, a plurality of second bolt holes are provided on the edge of the resistance adjustment plate, and the lower head is bolted to the lower head through the second bolt holes.

[0017] Preferably, a core outlet is provided on the side of the upper head.

[0018] Preferably, a core inlet is provided at the bottom of the lower head.

[0019] The technical solution of the embodiment of the present invention has at least the following advantages and beneficial effects:

[0020] The structure provided by the present invention relates to a core structure that improves the passive self-flowing capacity. The structure provided by the present invention mainly includes an upper head, a lower head and a cylinder arranged between the upper head and the lower head. A plurality of fuel assembly sleeves are arranged between the limit plate and the resistance adjustment plate. A resistance adjustment part is provided at the connection between the resistance adjustment plate and the fuel assembly sleeve. The resistance adjustment part is used to adjust the resistance of the fuel assembly sleeve inlet. Through the above structure, the fuel assembly flow distribution can be conveniently adjusted. Secondly, the core hanging plant and the descending annular cavity are eliminated, the 180° turn of the coolant flow is eliminated, and the flow resistance of the coolant in and out of the core is reduced. The combined effect of these two can improve the natural circulation potential of the reactor and thus improve the self-flowing capacity of the reactor. At the same time, the internal structure of the reactor is greatly simplified, most of the internal components of the reactor are eliminated, the difficulty and cost of core manufacturing are reduced, and the total weight of the core is reduced.

[0021] The core inlet resistance can be adjusted by the flow holes, and the flow distribution between different components can also be adjusted. The various parts of the core are connected by bolts, which is convenient for installation and operation and maintenance. The top limit plate is provided with a reflux hole so that the coolant can completely fill the area between the components in the core to achieve the moderation function. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0023] Figure 1 It is a schematic cross-sectional view of the core of the present invention;

[0024] Figure 2 The fuel assembly sleeve of the present invention is a cross-sectional schematic diagram and an axial schematic diagram of the fuel assembly sleeve;

[0025] Figure 3 It is a schematic diagram and a cross-sectional diagram of the resistance adjustment plate of the present invention;

[0026] Figure 4 Schematic diagram and cross-sectional diagram of the limiting plate of the present invention;

[0027] Figure 5 It is a schematic diagram of the principle of the resistance adjustment plate and the fuel assembly sleeve of the present invention cooperating with each other to achieve the flow distribution adjustment of the fuel assembly;

[0028] Figure 6 It is a schematic diagram of the coolant flow path in the core of the present invention.

[0029] Icons: 1-upper head, 2-cylinder, 3-lower head, 4-core inlet, 5-resistance adjustment plate, 6-flow hole, 7-outflow hole, 8-reflux hole, 9-limiting plate, 10-core outlet, 11-first bolt hole, 12-second bolt hole, 13-fuel assembly sleeve, 14-flow hole, 15-semicircular baffle, 16-assembly limiting groove, 17-limiting hole. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0031] Please refer to Figure 1-Figure 6 The present invention provides a core structure for improving the passive self-flowing capacity, comprising an upper head 1, a lower head 3 and a cylinder 2 arranged between the upper head 1 and the lower head 3;

[0032] The upper head 1 and the lower head 3 are both hemispherical in shape, and the barrel 2 is cylindrical in shape. A core outlet 10 is provided at the upper head, and a core inlet 4 is provided at one end of the lower head 3 .

[0033] A limit plate 9 is provided at one end of the cylinder 2 close to the upper end cap 1, and a resistance adjustment plate 5 is provided at one end close to the lower end cap 3. A plurality of fuel assembly sleeves 13 are provided between the limit plate 9 and the resistance adjustment plate 5. Both ends of the fuel assembly sleeves 13 are rotatably connected to the limit plate 9 and the resistance adjustment plate 5 respectively.

[0034] A resistance adjusting portion is provided at the connection between the resistance adjusting plate 5 and the fuel assembly sleeve 13 . The resistance adjusting portion and the resistance adjusting plate 5 are rotatably matched to adjust the resistance at the entrance of the fuel assembly sleeve 13 .

[0035] In an exemplary embodiment of the present invention, a fuel assembly sleeve 13 is provided with an outflow hole 7 at one end and a through-flow hole 14 at the other end. The resistance adjustment portion includes an assembly limiting groove 16 opened on the resistance adjustment plate 5 and a semicircular baffle 15 arranged in the through-flow hole 14. The end of the fuel assembly sleeve 13 with the semicircular baffle 15 is located in the assembly limiting groove 16 for rotation. A plurality of through-flow holes 6 are opened on the assembly limiting groove 16, and the coverage area of ​​the through-flow holes 6 is smaller than the area of ​​the through-flow hole 14.

[0036] Specifically, the fuel assembly sleeve 13 is a cylindrical hollow structure with one end closed and the other end open. The open end is a flow hole 14. A plurality of outflow holes 7 are provided on the side of the closed end of the fuel assembly sleeve 13. In the present embodiment, the size of the semicircular baffle 15 is half of the flow hole 14, and the area covered by the co-flow holes is also half of the flow hole 14. In actual use, it can be set according to different situations and is not limited to the setting example provided in the present embodiment. Secondly, the size of the flow hole 6 can also be changed. The outflow hole 7 is used for coolant to flow out of the fuel assembly sleeve 13.

[0037] When the structure is in use, the number of the flow holes 6 can be controlled by rotating the fuel assembly sleeve 13 and shielding the flow holes 6 with the semicircular baffle 15, thereby adjusting the flow distribution between different fuel assembly sleeves 13.

[0038] Secondly, several outflow holes 7 are arranged around one end of the fuel assembly sleeve 13. A rotating tool is arranged at one end of the fuel assembly sleeve 13 near the outflow hole 7, wherein the rotating tool is a cross-shaped protruding structure, which facilitates the rotation operation of the fuel assembly sleeve 13.

[0039] In an exemplary embodiment of the present invention, the limiting plate 9 is provided with a plurality of limiting holes, and one end of the fuel assembly sleeve 13 is located in the limiting hole for rotation.

[0040] Secondly, the limiting plate 9 is also provided with a plurality of reflux holes 8, so that the coolant can completely fill the area between the components in the core to achieve the moderation function. The edge of the limiting plate 9 is provided with a plurality of first bolt holes 11, and the limiting plate 9 is bolted to the cylinder 2 through the first bolt holes 11.

[0041] A plurality of second bolt holes 12 are formed on the edge of the resistance adjustment plate 5 , and the lower end cover 3 is bolted to the lower end cover 3 through the second bolt holes 12 .

[0042] The structure provided by the present invention mainly includes an upper head 1, a lower head 3 and a barrel 2 arranged between the upper head 1 and the lower head 3. A plurality of fuel assembly sleeves 13 are arranged between the limit plate 9 and the resistance adjustment plate 5. A resistance adjustment part is provided at the connection between the resistance adjustment plate 5 and the fuel assembly sleeve 13. The resistance adjustment part is used to adjust the resistance of the inlet of the fuel assembly sleeve 13. Through the above structure, the fuel assembly flow distribution can be conveniently adjusted. Secondly, the core hanging plant and the descending annular cavity are eliminated, the 180° turn of the coolant flow is eliminated, and the flow resistance of the coolant in and out of the core is reduced. The combined effect of these two can improve the natural circulation potential of the reactor and thus improve the self-flowing capacity of the reactor. At the same time, the internal structure of the reactor is greatly simplified, most of the internal components of the reactor are eliminated, the difficulty and cost of core manufacturing are reduced, and the total weight of the core is reduced.

[0043] Secondly, the core hanging plant and the descending annulus are eliminated, the 180° turn of the coolant flow is eliminated, and the flow resistance of the coolant in and out of the core is greatly reduced, thereby improving the natural circulation potential of the reactor. The structure of the internal components in the upper and lower heads is simplified, the manufacturing cost is reduced, and the total weight of the core is reduced;

[0044] The flow distribution between different components can also be adjusted by adjusting the resistance of the core inlet 4 through the flow holes 6. The various parts of the core are flexibly connected by bolts, which is convenient for installation and operation and maintenance. The top limit plate 9 is provided with a reflux hole 8 so that the coolant can completely fill the area between the components in the core to achieve the moderation function.

[0045] A semicircular area in the matching surface between the resistance adjustment plate 5 and the fuel assembly sleeve 13 is a solid area, and the other semicircular area is a flow area.

[0046] in, Figure 5Three different relationships are given in the figure: the flow hole is not blocked, the flow hole is half blocked, and the flow hole is completely blocked. When the solid semicircular areas of the two mating surfaces overlap, the flow capacity is maximum and the resistance is minimum. When the solid semicircular areas of the two mating surfaces correspond to the semicircular areas of the flowable fluid in another area, the fluid cannot flow through the component and the resistance is maximum.

[0047] When the solid semicircular areas of the two mating surfaces partially overlap, the resistance is related to the size of the overlapping area and can be adjusted continuously.

[0048] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A core structure for improving passive self-flow capability, characterized in that: It comprises an upper head (1), a lower head (3) and a cylinder (2) arranged between the upper head (1) and the lower head (3); A limit plate (9) is arranged at one end of the cylinder (2) close to the upper end cap (1), and a resistance adjustment plate (5) is arranged at one end close to the lower end cap (3). A plurality of fuel assembly sleeves (13) are arranged between the limit plate (9) and the resistance adjustment plate (5), and two ends of the fuel assembly sleeves (13) are rotatably connected to the limit plate (9) and the resistance adjustment plate (5) respectively. A resistance adjusting portion is provided at the connection between the resistance adjusting plate (5) and the fuel assembly sleeve (13); the resistance adjusting portion and the resistance adjusting plate (5) are rotatably matched to adjust the resistance of the inlet of the fuel assembly sleeve (13).

2. A core structure for improving passive self-flow capability according to claim 1, characterized in that: One end of the fuel assembly sleeve (13) is provided with an outflow hole (7), and the other end is provided with a through-flow hole (14); the resistance adjustment portion comprises an assembly limiting groove (16) provided on the resistance adjustment plate (5) and a semicircular baffle (15) provided in the through-flow hole (14); one end of the fuel assembly sleeve (13) with the semicircular baffle (15) is located in the assembly limiting groove (16) for rotation; a plurality of through-flow holes (6) are provided in the upper semicircular region of the assembly limiting groove (16); and the coverage area of ​​the through-flow holes (6) is smaller than the area of ​​the through-flow hole (14).

3. A core structure for improving passive self-flow capability according to claim 2, characterized in that: A plurality of outflow holes (7) are arranged around one end of the fuel assembly sleeve (13).

4. A core structure for improving passive self-flow capability according to claim 3, characterized in that: A rotating tool is provided at one end of the fuel assembly sleeve (13) close to the outflow hole (7).

5. A core structure for improving passive self-flow capability according to claim 4, characterized in that: The limiting plate (9) is provided with a plurality of limiting holes, and one end of the fuel assembly sleeve (13) is located in the limiting hole and rotates.

6. A core structure for improving passive self-flow capability according to claim 5, characterized in that: The limiting plate (9) is also provided with a plurality of reflux holes (8).

7. A core structure for improving passive self-flow capability according to claim 6, characterized in that: A plurality of first bolt holes (11) are provided on the edge of the limiting plate (9), and the limiting plate (9) is bolted to the cylinder (2) via the first bolt holes (11).

8. A core structure for improving passive self-flow capability according to claim 7, characterized in that: A plurality of second bolt holes (12) are provided on the edge of the resistance adjustment plate (5), and the lower sealing head (3) is bolted to the lower sealing head (3) via the second bolt holes (12).

9. A core structure for improving passive self-flow capability according to any one of claims 1 to 8, characterized in that: A core outlet (10) is provided on the side of the upper head (1).

10. A core structure for improving passive self-flow capability according to claim 9, characterized in that: A core inlet (4) is arranged at the bottom of the lower head (3).

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