A rod bundle flow channel inner grid sliding device

Abstract

The application discloses a kind of rod bundle flow channel inner grid slip devices, at least including four strong magnets, support block, control rod, pin, and several rod bundles, grid and flow channel wall, support block is cylindrical and in middle reserved space of embedding strong magnet;Strong magnet is embedded in support block and keeps the upper and lower surfaces of strong magnet and support block flat;The number of several rod bundles is N*N, N is greater than or equal to two, and the rod bundle is composed of acrylic tube, the inner diameter of the acrylic tube is greater than the diameter of the cylindrical support block, and the outer diameter of the acrylic tube is less than the inner diameter of the ring of the grid;Internal thread is processed on the upper end of support block, external thread is processed on the lower end of control rod, and control rod and support block are connected by thread;Support block slides up and down along the axis of rod bundle under the drive of control rod;Rod bundle is sleeved in the ring of grid, and rod bundle is fixed in position using grid;Small holes are reserved in flow channel wall, and internal thread holes are reserved in corresponding position of grid, when control rod moves up and down and drives grid to move to predetermined position, grid is fixed on flow channel wall using pin.

Description

Technical Field

[0001] This invention relates to the field of experimental measurement technology of reactor thermal fluids, and in particular to a grid sliding device in a rod bundle flow channel. Background Technology

[0002] In nuclear power systems, fuel rods are typically installed in the reactor core in the form of rod bundles. Grids are key geometric components within the rod bundle flow channels. Positioning grids serve to position and fix the fuel rods, while mixing grids play an important role in mixing different sub-channels within the rod bundle flow channels, enhancing heat transfer, and increasing the critical heat flux density.

[0003] In reactor safety analysis and novel grid design, it is necessary to measure the flow characteristics downstream of the grid within the rod bundle flow channel, including the cold flow field, the phase field of the gas-liquid two-phase flow, the temperature distribution in the hot state, and the steam distribution.

[0004] The bar bundle structure is complex. Taking the probe and wire mesh sensor for measuring gas-liquid two-phase flow as an example, in specific experiments, the sensor is installed in the flow channel at a certain axial position. Changing the axial position of the sensor is very difficult, making it difficult to conduct precise measurements of the flow evolution downstream of the grid.

[0005] Given the need for measuring the downstream flow characteristics of the grid in reactor thermal fluid experiments, this invention proposes a grid sliding device within the rod bundle flow channel. Summary of the Invention

[0006] To overcome the shortcomings of the prior art, the present invention provides a grid sliding device in a rod bundle flow channel.

[0007] To achieve the aforementioned objectives of the invention, the technical solution adopted to solve its technical problems is as follows:

[0008] A rod bundle flow channel internal grid sliding device includes at least four strong magnets, a support block, a control rod, a pin, and several rod bundles, grids, and flow channel walls, wherein:

[0009] The support block is cylindrical, with a space reserved in the middle for embedding the strong magnet;

[0010] The strong magnet is embedded in the support block, and the upper and lower surfaces of the strong magnet and the support block are kept flat.

[0011] The number of the aforementioned rod bundles is N*N, where N is greater than or equal to two. The rod bundles are composed of acrylic tubes, the inner diameter of which is greater than the cylindrical diameter of the support block, and the outer diameter of which is smaller than the inner diameter of the grid ring.

[0012] The upper end of the support block is machined with internal threads, and the lower end of the control rod is machined with external threads. The control rod and the support block are connected by threads. The support block slides up and down along the axial direction of the rod bundle under the drive of the control rod.

[0013] The rod bundle is sleeved in the ring of the grid frame, and the rod bundle is fixed in position by the grid frame;

[0014] Small holes are pre-drilled in the flow channel wall, and internal threaded holes are pre-drilled in the corresponding positions of the grid frame. When the control rod moves up and down, it drives the grid frame to a predetermined position, and then the grid frame is fixed to the flow channel wall with pins.

[0015] Preferably, the strong magnet is first processed into an arc shape, and the diameter of the arc is equal to the diameter of the support block.

[0016] Furthermore, the grid has protrusions near the flow channel wall that contact the inner wall surface of the flow channel, in order to ensure hard contact between the grid and the flow channel and thus prevent the grid from loosening.

[0017] Furthermore, the number of the plurality of rod bundles is four, located at the four corners of the rod bundle flow channel, and each of the rod bundles is fitted with a support block containing a strong magnet.

[0018] Preferably, the strong magnets of the support blocks in different rod bundles are oriented in the same direction.

[0019] Preferably, the difference between the inner diameter of the acrylic tube and the cylindrical diameter of the support block does not exceed 0.1 mm.

[0020] Preferably, the difference between the inner diameter of the grid ring and the outer diameter of the acrylic tube does not exceed 0.1 mm.

[0021] Furthermore, pin holes are reserved on the grid corresponding to the rod bundle at the center of the four sides of the rod bundle flow channel.

[0022] Preferably, the grid is made of stainless steel.

[0023] By employing the above technical solutions, this invention has the following advantages and positive effects compared with the prior art:

[0024] This invention proposes a grid sliding device within a rod bundle flow channel. The device includes a support block mounted on the inner wall of the rod bundle and a strong magnet. The support block is connected to a control rod to allow the strong magnet to move up and down within the rod bundle. The grid is made of stainless steel, and the sliding of the strong magnet drives the grid to slide. Once the grid has moved to a certain position, it is fixed to the flow channel wall using pins. This grid sliding device within the rod bundle flow channel can be used for experimental research on the flow characteristics downstream of the grid. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In the drawings:

[0026] Figure 1 This is a cross-sectional view of a grid sliding device in a rod bundle flow channel according to the present invention;

[0027] Figure 2 This is a longitudinal cross-sectional view of a single rod of a rod bundle flow channel internal grid sliding device according to the present invention.

[0028] [Explanation of Key Symbols]

[0029] 1-Strong magnet; 2-Support block; 3-Control rod; 4-Bar bundle; 5-Grid; 6-Pin; 7-Flow channel wall. Detailed Implementation

[0030] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0032] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0033] In nuclear power systems, fuel rods are typically installed in the reactor core in the form of rod bundles, with the rods secured to each other using a grid. Studying the flow characteristics downstream of the grid within the rod bundle channels is crucial for reactor safety analysis. Due to the complexity of the rod bundle channels, it is difficult to adjust the axial position of measuring equipment such as wire mesh sensors. Therefore, it is essential to measure the downstream flow field by adjusting the axial position of the grid.

[0034] like Figure 1 and 2 As shown, this embodiment discloses a sliding device for a grid within a rod bundle flow channel, comprising at least four strong magnets 1, a support block 2, a control rod 3, a pin 6, and several rod bundles 4, a grid 5, and a flow channel wall 7, wherein:

[0035] The support block 2 is cylindrical, with a space reserved in the middle for embedding the strong magnet 1;

[0036] The strong magnet 1 is embedded in the support block 2, and the upper and lower surfaces of the strong magnet 1 and the support block 2 are kept flat. In this embodiment, in order to ensure the flatness of the cylindrical surface, strong adhesive is used to stably bond the strong magnet 1 and the support block 2.

[0037] The number of the rod bundles 4 is N*N, where N is greater than or equal to two. The rod bundles 4 are composed of acrylic tubes with a wall thickness of 2mm. The inner diameter of the acrylic tube is slightly larger than the cylindrical diameter of the support block 2, and the outer diameter of the acrylic tube is slightly smaller than the inner diameter of the ring of the grid 5.

[0038] The upper end of the support block 2 is machined with internal threads, and the lower end of the control rod 3 is machined with external threads. The control rod 3 and the support block 2 are connected by threads. The support block 2 slides up and down along the axial direction of the rod bundle 4 (acrylic tube) under the drive of the control rod 3.

[0039] The rod bundle 4 is sleeved in the ring of the grid 5, and the rod bundle 4 is fixed in position by the grid 5;

[0040] A small hole with a diameter of 3mm is reserved in the flow channel wall 7, and an internal threaded hole is reserved in the corresponding position of the grid 5. When the control rod 3 moves up and down, it drives the grid 5 to move to the predetermined position. The grid 5 is fixed to the flow channel wall 7 with a pin 6, and the sealing between the pin 6 and the flow channel is ensured by using PTFE tape.

[0041] Preferably, the strong magnet 1 is firstly machined into an arc shape, and the diameter of the arc is equal to the diameter of the support block 2.

[0042] Furthermore, the grid 5 is machined with protrusions near the flow channel wall 7 that contact the inner wall surface of the flow channel wall 7, in order to ensure hard contact between the grid 5 and the rod bundle flow channel and thus prevent the grid 5 from loosening.

[0043] Furthermore, the number of the plurality of rod bundles 4 is four, located at the four corners of the rod bundle flow channel, and each rod bundle 4 is fitted with a support block 2 for a strong magnet 1. Preferably, the strong magnets 1 in the support blocks 2 of different rod bundles 4 are oriented in the same direction.

[0044] Preferably, to ensure smooth sliding of the support block 2, the difference between the inner diameter of the acrylic tube and the cylindrical diameter of the support block 2 does not exceed 0.1 mm.

[0045] Preferably, to ensure smooth sliding of the grid 5, the difference between the inner diameter of the grid 5 ring and the outer diameter of the acrylic tube does not exceed 0.1 mm.

[0046] Furthermore, to ensure that the grid 5 is firmly fixed, pin holes are reserved on the grid 5 corresponding to the rod bundle 4 at the center of the four sides of the rod bundle flow channel.

[0047] Preferably, the grid 5 is made of stainless steel.

[0048] Figure 1 This is a cross-sectional schematic diagram of a 3×3 rod bundle flow channel internal grid sliding device. Support blocks 2, each containing a strong magnet 1, are installed within one of the four diagonally opposite rods. The diameter of the support block 2 is equal to the inner diameter of the rod bundle 4. The strong magnets 1 are installed in the same orientation within the different rod bundles 4, attracting the stainless steel grid 5 through the wall of the rod bundle 4. The support blocks 2 are connected to control rods 3, as shown... Figure 2 As shown. The up-and-down movement of the control lever 3 causes the strong magnet 1 to slide up and down, thereby realizing the up-and-down movement of the grid 5. Pin holes are reserved in the flow channel wall 7 and the grid 5. After the grid 5 slides to the predetermined position, the pin 6 is used to fix the grid 5 to the wall surface of the flow channel wall 7.

[0049] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A grid sliding device for a rod bundle flow channel, characterized in that, It includes at least four strong magnets, a support block, a control rod, pins, and several rod bundles, grids, and flow channel walls, wherein: The support block is cylindrical, with a space reserved in the middle for embedding the strong magnet; The strong magnet is embedded in the support block, and the upper and lower surfaces of the strong magnet and the support block are kept flat. The number of the aforementioned rod bundles is N*N, where N is greater than or equal to two. The rod bundles are composed of acrylic tubes, the inner diameter of which is greater than the cylindrical diameter of the support block, and the outer diameter of which is smaller than the inner diameter of the grid ring. The upper end of the support block is machined with internal threads, and the lower end of the control rod is machined with external threads. The control rod and the support block are connected by threads. The support block slides up and down along the axial direction of the rod bundle under the drive of the control rod. The rod bundle is sleeved in the ring of the grid frame, and the rod bundle is fixed in position by the grid frame; Small holes are pre-drilled in the flow channel wall, and internal threaded holes are pre-drilled in the corresponding positions of the grid frame. When the control rod moves up and down, it drives the grid frame to a predetermined position, and then the grid frame is fixed to the flow channel wall with pins.

2. The rod bundle flow channel internal grid sliding device according to claim 1, characterized in that, The strong magnet is firstly machined into an arc shape, and the diameter of the arc is equal to the diameter of the support block.

3. The rod bundle flow channel internal grid sliding device according to claim 1, characterized in that, The grid has protrusions near the flow channel wall that contact the inner wall surface of the flow channel, which are used to ensure hard contact between the grid and the flow channel and thus prevent the grid from loosening.

4. The rod bundle flow channel internal grid sliding device according to claim 1, characterized in that, The number of the aforementioned rod bundles is four, located at the four corners of the rod bundle flow channel, and each of the rod bundles is equipped with a support block containing a strong magnet.

5. The rod bundle flow channel internal grid sliding device according to claim 4, characterized in that, The strong magnets of the support blocks in different rod bundles are oriented in the same direction.

6. The rod bundle flow channel internal grid sliding device according to claim 1, characterized in that, The difference between the inner diameter of the acrylic tube and the cylindrical diameter of the support block does not exceed 0.1 mm.

7. The rod bundle flow channel internal grid sliding device according to claim 1, characterized in that, The difference between the inner diameter of the grid ring and the outer diameter of the acrylic tube shall not exceed 0.1 mm.

8. The rod bundle flow channel internal grid sliding device according to claim 1, characterized in that, Pin holes are reserved on the grid corresponding to the rod bundle at the center of the four sides of the rod bundle flow channel.

9. The rod bundle flow channel internal grid sliding device according to claim 1, characterized in that, The grid is made of stainless steel.

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