Rod bundle grillwork of reactor core mixing reinforced structure

Abstract

The utility model relates to a rod bundle grillwork of a reactor core mixing enhancing structure, which comprises flow guide inclined surface mixing wings, longitudinal channel water flow increasing holes, rod bundle positioning support blocks and a support frame body, the flow guide inclined surface mixing wings are uniformly distributed in the grillwork in the circumferential direction, the longitudinal channel water flow increasing holes are uniformly distributed on the grillwork, and the rod bundle positioning support blocks are arranged on the support frame body. The rod bundle positioning supporting blocks are uniformly distributed on the hole wall in the center of the grillwork; the bracket frame body is connected with the flow guide inclined surface stirring and mixing wings, the longitudinal channel water flow increasing holes and the rod bundle positioning supporting blocks. The stirring and mixing grillwork disclosed by the utility model can provide a better supporting function for a fuel rod bundle in a pressurized water reactor, and the holes in the grillwork can better promote stirring and mixing of coolants among channels of a reactor core; the convection heat exchange between the wall surface of the fuel rod and the coolant is enhanced, the heat generated by the fuel rod can be more effectively led out, the temperature of the core block and the surface of the fuel rod is reduced, and the safety of a reactor core is protected; and mass, momentum and energy exchange between adjacent channels of the fuel rod bundle is promoted, so that the temperature distribution of the coolant tends to be uniform.

Description

Technical Field

[0001] The utility model relates to the field of fuel assemblies, in particular to a rod bundle grid of a core stirring and enhancing structure. Background Art

[0002] At present, the method of experimental verification is mainly used for mixing enhanced rod bundle grids, which has a long cycle, high cost, and consumes a lot of manpower and material resources. After the 1970s, especially in recent years, foreign countries have made great progress in using numerical methods to study the influence of mixing grids on the thermal and hydraulic performance of the core. They use angled welded or punched mixing wing grids. In China, research in this area has just started, and some research has been conducted mainly on the influence of the mixing blades of the mixing grid on the flow field. This research mainly focuses on the role and structure of the mixing wings of the mixing grid, such as Figure 1 The numerical method was used to study the three-dimensional flow field of a single-phase fluid in a mixing grid (referred to as the grid). The structure of this 2X2 grid is shown in Figure 2 These structural features are that the grid mixing wings are welded or punched out of the mold with angled mixing wings, the rod bundle is fixed by the mixing wings, and the mixing wings have design angle requirements, which will have the following defects:

[0003] 1. The rigidity is not good, and the mixing wings take up extra space when working.

[0004] 2. These design structures themselves bring great difficulties to machining and the processing cost is high.

[0005] 3. More time is spent in the assembly and disassembly process. The main problem is that when clamping and positioning the heating rods, threaded holes need to be opened on the grid to cooperate with the screws to tighten the rod bundle, which causes great problems in clamping and disassembly.

[0006] 4. The angle of the mixing wing in actual clamping directly affects the cross-flow mixing flow rate due to the pressure water flow during assembly or experiment, and the mixing wing produces a pressure drop during operation. Utility Model Content

[0007] In order to solve the technical problems existing in the prior art, the utility model provides a core stirring reinforcement structure rod bundle grid.

[0008] In order to achieve the above object, the technical solution of the utility model is as follows:

[0009] A core mixing enhancement structure rod cluster grid comprises a guide bevel mixing wing, a longitudinal channel water flow enhancement hole, a rod cluster positioning support block, and a support frame. The guide bevel mixing wing is evenly distributed circumferentially inside the grid, the longitudinal channel water flow enhancement hole is evenly arranged on the grid, the rod cluster positioning support block is evenly arranged on the hole wall at the center of the grid, and the support frame is connected with the guide bevel mixing wing, the longitudinal channel water flow enhancement hole and the rod cluster positioning support block.

[0010] As a preferred technical solution, the guide inclined mixing wing is an inscribed integrated inclined mixing wing.

[0011] As a preferred technical solution, the support frame includes an outer frame, a hexagonal tube and a connecting plate, and the outer frame is fixedly connected to the hexagonal tube via the connecting plate.

[0012] As a preferred technical solution, the shape of the outer frame is circular.

[0013] As a preferred technical solution, the hexagonal tube is located at the center of the grid, and the rod bundle positioning support block is fixedly arranged at the middle position of each side of the hexagonal tube.

[0014] As an optimal technical solution, a circumferentially evenly distributed convex portion is provided on the inner side of the outer frame, the longitudinal channel water flow enhancement holes are arranged on the convex portion, the guide inclined mixing wings are located on the side of the convex portion, and the convex portion is fixedly connected to the corner position of the hexagonal tube through a connecting plate.

[0015] Compared with the prior art, the beneficial effects of the utility model are:

[0016] (1) The mixing reinforced structure rod bundle grid of the utility model is convenient for machining and production in a pressurized water reactor, which can reduce costs, has better rigidity, and presents an integrated structure. Compared with the existing grid, it can provide better support function for the fuel rod bundle;

[0017] (2) The rod bundle grid of the mixing enhancement structure of the utility model can design the size of the inscribed mixing wing according to the required cross-flow mixing flow and the convection flow between the rod bundles obtained by scientific calculation, and more accurately promote the mixing of the coolant between the channels of the core according to the mixing requirements. Among them, a circumferential guide slope is designed to force the axially flowing fluid to produce a circumferential velocity component, thereby causing the fluid to rotate along the axis of the pipe. This rotational motion can cause the fluid in the pipe to mix, thereby making the temperature of the fluid in the pipe tend to be uniform.

[0018] (3) The rod bundle grid of the mixing enhancement structure of the utility model has an inscribed mixing wing that is easier to assemble and has a more accurate angle in actual use than an outbound mixing wing. The inscribed mixing wing does not take up additional space, nor does it produce a pressure drop during mixing like a general mixing wing.

[0019] (4) The rod bundle grid of the mixing enhancement structure of the utility model is simple and practical. Because of the change in the mixing wing structure, there is no need to consider and calculate the reduction caused by the mixing wing in the fluid, nor is there any need to worry about the grid positioning problem and the deformation of the mixing wing itself due to insufficient structural rigidity.

[0020] (5) The rod bundle grid of the mixing enhancement structure of the utility model is more stable when mixing the fluid, and circular holes are opened on the grid. The hole size can be adjusted in a small range, which can better cooperate with the mixing wings to obtain a uniform fluid temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic structural diagram of an angled mixing wing in the prior art of the utility model;

[0022] Figure 2 It is a structural diagram of a mixing grid in the prior art of the utility model;

[0023] Figure 3 It is a structural schematic diagram of the rod bundle grid of the core stirring enhancement structure of the utility model;

[0024] Figure 4 This is a front view of the core stirring enhancement structure of the utility model;

[0025] Figure 5 It is a cross-sectional view of the mixing structure in the core mixing enhancement structure of the utility model.

[0026] In the figure: 1. guide slope mixing wing; 2. longitudinal channel water flow enhancement hole; 3. rod bundle positioning support block; 4. bracket frame. DETAILED DESCRIPTION

[0027] The technical solution of the utility model is further described below in conjunction with specific implementation methods:

[0028] like Figure 3 As shown, a core mixing enhancement structure rod bundle grid includes a guide bevel mixing wing 1, a longitudinal channel water flow enhancement hole 2, a rod bundle positioning support block 3, and a support frame 4. The guide bevel mixing wing 1 is evenly distributed inside the grid in the circumferential direction. The guide bevel mixing wing 1 is cut out from the inside of the grid itself, mainly to better achieve lateral mixing of the fluid. The longitudinal channel water flow enhancement holes 2 are evenly arranged on the grid, so as to better achieve convective heat exchange between the fuel rod wall and the coolant, more effectively conduct the heat generated by the fuel rods, reduce the fuel rod core block and surface temperature, and protect the safety of the core. On the other hand, the mixing grid promotes the mass, momentum and energy exchange between adjacent channels of the fuel rod bundle, so that the temperature distribution of the coolant tends to be uniform, which is also more conducive to protecting the safety of the core.

[0029] The rod cluster positioning support blocks 3 are evenly arranged on the hole wall in the center of the grid, which can better constrain and support the fuel rods. The support frame 4 is connected with the guide slope mixing wing 1, the longitudinal channel water flow increase hole 2 and the rod cluster positioning support blocks 3. The support frame 4 is simple, practical and easy to process.

[0030] The flow-guiding inclined mixing wing 1 is an inscribed integrated inclined mixing wing. This structure intuitively shows the position where the fluid is converted into a lateral rotation after passing through the inclined surface, and the size of this inclined surface can be changed according to the actual lateral fluid flow calculation.

[0031] like Figure 4 As shown, the support frame 4 includes an outer frame, a hexagonal tube and a connecting plate, and the outer frame is fixedly connected to the hexagonal tube through the connecting plate.

[0032] The shape of the outer frame is circular.

[0033] The hexagonal tube is located at the center of the grid, and the rod cluster positioning support block 3 is fixedly arranged at the middle position of each side of the hexagonal tube.

[0034] The inner side of the outer frame is provided with convex parts evenly distributed in the circumference, the longitudinal channel water flow enhancement holes 2 are arranged on the convex parts, the guide inclined mixing wings 1 are located on the side of the convex parts, and the convex parts are fixedly connected to the corners of the hexagonal tubes through the connecting plates.

[0035] This embodiment is only a further explanation of the present invention, not a limitation of the present invention. After reading this specification, those skilled in the art may make non-creative modifications to this embodiment as needed, but as long as it is within the scope of the claims of the present invention, it will be protected by the patent law.

Claims

1. A core stirring reinforcement structure rod bundle grid, characterized in that: The invention comprises a flow guiding inclined mixing wing, a longitudinal channel water flow increasing hole, a rod cluster positioning support block, and a support frame. The flow guiding inclined mixing wing is evenly distributed inside the grid in the circumferential direction, the longitudinal channel water flow increasing hole is evenly arranged on the grid, the rod cluster positioning support block is evenly arranged on the hole wall in the center of the grid, and the support frame is connected with the flow guiding inclined mixing wing, the longitudinal channel water flow increasing hole and the rod cluster positioning support block.

2. The core mixing reinforcement structure rod bundle grid according to claim 1, characterized in that: The guide inclined mixing wing is an inscribed integrated inclined mixing wing.

3. The core mixing reinforcement structure rod bundle grid according to claim 1, characterized in that: The support frame comprises an outer frame, a hexagonal tube and a connecting plate, and the outer frame is fixedly connected to the hexagonal tube via the connecting plate.

4. The core mixing reinforcement structure rod bundle grid according to claim 3, characterized in that: The outer frame is circular in shape.

5. The core mixing reinforcement structure rod bundle grid according to claim 3, characterized in that: The hexagonal tube is located at the center of the grid, and the rod bundle positioning support block is fixedly arranged at the middle position of each side of the hexagonal tube.

6. The core mixing reinforcement structure rod bundle grid according to claim 3, characterized in that: The inner side of the outer frame is provided with convex parts evenly distributed in the circumference, the longitudinal channel water flow enhancement holes are arranged on the convex parts, the guide inclined mixing wings are located on the sides of the convex parts, and the convex parts are fixedly connected to the corners of the hexagonal tubes through connecting plates.

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