Control rod drive mechanism seismic test restraint device

Abstract

The application provides a control rod drive mechanism anti-seismic test restraint device, and relates to the technical field of control rod drive mechanism anti-seismic test. The control rod drive mechanism anti-seismic test restraint device comprises a center limiting component, a plurality of adjustable pull rod assemblies and an external fixing component. The center limiting component is configured to be sleeved or fixed on the top of the control rod drive mechanism through a mounting portion, and a plurality of hinged seats are uniformly arranged on the circumference of the center limiting component. The length of the adjustable pull rod assembly is adjustable, the inner end of each adjustable pull rod assembly is hinged to the corresponding hinged seat, and the outer end of the adjustable pull rod assembly is connected with the external fixing component. Wherein, the plurality of adjustable pull rod assemblies are uniformly distributed along the circumference of the center limiting component. The external fixing component is configured to be connected with the fixed structure or the counterforce structure of the seismic station.

Description

Technical Field

[0001] This invention relates to the field of seismic testing technology for nuclear reactor control rod drive mechanisms, and more particularly to a seismic testing constraint device for control rod drive mechanisms. Background Technology

[0002] The control rod drive mechanism is a core safety device in a nuclear reactor, responsible for raising, lowering, and holding the control rods, directly affecting the reactor's reactivity control and safe shutdown capabilities. Under extreme loads such as earthquakes, the control rod drive mechanism must maintain structural integrity and functional reliability. In seismic tests of the control rod drive mechanism, a constraint device is typically installed at the top of the drive mechanism to simulate the boundary conditions of the top support of the drive rods.

[0003] Existing constraint devices mostly employ integrated rigid plate seismic plates, which are fixed to the fixed frame or reaction frame of the test rig. These plates constrain the top of the test specimen (specifically, the control rod drive mechanism specimen), and the width of the plate creates a radial limiting clearance for the top of the control rod drive mechanism. However, this type of seismic plate has the following drawbacks: the force path of the integrated rigid plate structure extends along the plate surface. Due to the plate's stiffness, it is prone to warping deformation when the seismic station undergoes attitude deflection. Additional bending moments and lateral shear forces may appear in the constraint load and be transmitted to the test specimen and its connections, interfering with the preset test boundary conditions. Furthermore, the limiting clearance between the test specimen and the seismic station is mainly determined by the processing dimensions and installation state of the seismic plate, lacking adjustment and compensation capabilities. The constraint boundaries may differ under different assembly states, affecting the repeatability and consistency of the test results. Summary of the Invention

[0004] The purpose of this invention is at least to provide a seismic test constraint device for a control rod drive mechanism, which can improve the force mode of the constraint device, reduce the influence of additional bending load and lateral shear load on the test specimen, and improve the stability of the test boundary conditions, the accuracy and repeatability of the test data.

[0005] The following provides a brief overview of one or more aspects to offer a basic understanding of them. This overview is not an exhaustive summary of all conceived aspects, nor is it intended to identify key or decisive elements of all aspects, nor to define the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form to prepare for the more detailed descriptions that follow.

[0006] One embodiment of the present invention provides a seismic test constraint device for a control rod drive mechanism, including a central limiting component, multiple sets of adjustable tie rod assemblies, and external fixing components.

[0007] The central limiting component is configured to be fitted or fixed to the top of the control rod drive mechanism via the mounting part, and multiple hinge seats are evenly arranged around the central limiting component.

[0008] The length of the adjustable tie rod assembly is adjustable. The inner end of each adjustable tie rod assembly is hinged to the corresponding hinge seat, and the outer end of the adjustable tie rod assembly is connected to the external fixed component. Multiple adjustable tie rod assemblies are evenly distributed circumferentially along the central limiting component.

[0009] The external fixing components are configured as a fixed structure or reaction structure to connect to the seismic station.

[0010] The constraint structure, formed by a central limiting component, adjustable tie rod assembly, and external fixing components, ensures that the constraint load during minor attitude changes of the seismic station remains primarily axial tensile and compressive, reducing the probability of additional bending and lateral shear loads entering the test specimen and threaded connections, thus minimizing the risk of damage caused by non-target forces. It also reduces the disturbance of the test boundary conditions caused by the warping deformation of the constraint device itself, making the dynamic response of the test specimen closer to the preset boundary state, improving the accuracy and analyzability of the test data. Furthermore, it reduces the destructive effect of lateral shear forces on threaded pairs and connections, enhancing connection stability during multiple assembly, adjustment, and vibration tests.

[0011] In some embodiments, the hinge seat is a U-shaped fork lug seat, which has two spaced-apart fork arms, and the inner end of the adjustable pull rod assembly is located between the two fork arms of the corresponding U-shaped fork lug seat.

[0012] The two spaced fork arms of the U-shaped fork lug form a stable hinged fit with the inner end of the adjustable pull rod assembly, which helps to maintain the stress stability of the connection part.

[0013] In some embodiments, each adjustable lever assembly includes a pin and an adjusting screw. The inner end of the adjusting screw is inserted between the two fork arms of the corresponding U-shaped fork lug and is hinged to the U-shaped fork lug via the pin. The outer end of the adjusting screw is connected to an external fixing member.

[0014] The pin and adjusting screw work together to achieve a hinged connection between the adjusting screw and the U-shaped fork lug, making it easier to transmit the constraint load in axial tension and compression, and reducing the influence of additional bending load and lateral shear load.

[0015] In some embodiments, the inner end of the adjusting screw is provided with a pin hole, and the pin shaft is inserted through the pin hole and hinged to the U-shaped fork lug seat. The pin hole is arranged along the vertical plane.

[0016] The pin holes are arranged along the vertical plane, which helps to maintain the hinged motion relationship between the adjusting screw and the U-shaped fork lug, and improves the stress adaptability of the connection part during vibration.

[0017] In some embodiments, each adjustable lever assembly further includes a locking nut assembly, which includes at least two nuts that are threadedly connected to the adjusting screw and are located on the inner and outer sides of the external fixing member, respectively.

[0018] The locking nut assembly is located on the inner and outer sides of the external fixing component, which helps to reliably position the adjusting screw and improve the connection stability.

[0019] In some embodiments, multiple sets of adjustable pull rod assemblies are configured to independently adjust the extension length, and the locking nut assembly is used to lock the adjusting screw after the corresponding adjusting screw has completed the extension length adjustment.

[0020] The extension length can be independently adjusted and the adjusting screw can be locked after adjustment. This can correct the eccentricity of the test piece installation, reduce the risk of local contact, collision and off-center load, and suppress screw loosening and set value drift under vibration environment, thereby improving boundary condition stability and consistency of repeated assembly.

[0021] In some embodiments, the central limiting member is a disc-shaped structure, and its mounting portion is located at the center of the central limiting member.

[0022] The mounting section is located at the center of the disc-shaped structure, which helps to position the top support rod of the control rod drive mechanism at the center of the central limiting member, thereby improving the symmetry of the constraint arrangement.

[0023] In some embodiments, the mounting portion is a mounting hole, which is arranged in a horizontal direction.

[0024] The mounting holes are arranged horizontally, which facilitates the fitting or fixing of the top support rod of the control rod drive mechanism through the mounting holes, forming a stable top support constraint.

[0025] In some embodiments, multiple sets of adjustable tie rod assemblies are evenly and symmetrically distributed along the circumference of the central limiting member, and the multiple sets of adjustable tie rod assemblies and the central limiting member are arranged on the same horizontal plane, so that the constraint stiffness of the constraint device is consistent in all horizontal directions.

[0026] Multiple sets of adjustable tie rod assemblies are evenly and symmetrically distributed along the circumference of the central limiting component and arranged on the same horizontal plane as the central limiting component, so that the constraint stiffness in each horizontal direction is consistent, reducing the response bias caused by the difference in boundary stiffness in different directions, and improving the symmetry of the boundary conditions of the vibration test.

[0027] In some embodiments, the number of adjustable pull rod assemblies is four sets, and the four sets of adjustable pull rod assemblies are symmetrically distributed at 90° intervals along the circumference of the central limiting member.

[0028] The four sets of adjustable tie rod assemblies are symmetrically distributed at 90° intervals, which helps to jointly limit the displacement of the control rod drive mechanism in mutually orthogonal horizontal directions and form anti-torsional constraints, reduce the risk of collisions, local load concentration and test interruption caused by attitude drift, and improve the repeatability of test results. Attached Figure Description

[0029] The above-described features and advantages of the present invention will be better understood after reading the following detailed description of embodiments of the present disclosure in conjunction with the accompanying drawings. In the drawings, components are not necessarily drawn to scale, and components having similar related properties or features may have the same or similar reference numerals. Wherein: Figure 1 This is a top view of the overall structure of the control rod drive mechanism seismic test constraint device according to some embodiments.

[0030] Figure 2 This is a vertical cross-sectional view of the seismic test constraint device for the control rod drive mechanism, as shown in some embodiments.

[0031] Figure 3 This is a structural schematic diagram of the center limiting member according to some embodiments.

[0032] Figure 4 This is a schematic diagram of the structure of the adjusting screw according to some embodiments.

[0033] Explanation of reference numerals in the attached figures: 1-Center limiting component; 11-Installation Department; 12-Hinged base; 2- Adjustable pull rod assembly; 21-Adjusting screw; 211-Pin hole; 212 - External thread; 22-Pin; 23- Locking nut assembly; 3-External fixing components. Detailed Implementation

[0034] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. It should be noted that the aspects described below with reference to the accompanying drawings and specific embodiments are merely exemplary and should not be construed as limiting the scope of protection of the present invention in any way.

[0035] It is understood that the technical terms that may be used in the description of this specification, such as “center,” “longitudinal,” “lateral,” “front,” “rear,” “left,” “right,” “vertical,” “horizontal,” “top,” “bottom,” “inner,” and “outer,” indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the implementation method 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 limiting the scope of protection of the invention.

[0036] It should be noted that the use of terms such as "first" and "second" to define features in this document is merely for the purpose of distinguishing the corresponding features. Unless otherwise stated, these terms have no special meaning and should not be construed as limiting the scope of protection of this invention. As shown in this specification and claims, the terms "a," "an," "an," and / or "the" do not specifically refer to the singular and may also include the plural, unless the context clearly indicates otherwise. Generally, the terms "comprising" and "including" only indicate the inclusion of explicitly identified steps and elements, and these steps and elements do not constitute an exclusive list; the method or apparatus may also include other steps or elements.

[0037] like Figure 1 and Figure 2 As shown in the embodiments of this specification, a seismic testing constraint device for a control rod drive mechanism is proposed. The constraint device includes a central limiting member 1, multiple sets of adjustable tie rod assemblies 2, and an external fixing member 3. The constraint device is centrally symmetrically arranged. The central limiting member 1 is located at the geometric center of the constraint device. The multiple sets of adjustable tie rod assemblies 2 are radially distributed outward from the central limiting member 1 along the circumference. The inner ends of the adjustable tie rod assemblies 2 are hinged to the central limiting member 1, and the outer ends of the adjustable tie rod assemblies 2 are connected to the external fixing member 3. The external fixing member 3 is configured as a fixed structure or reaction structure connecting to the seismic station, providing an external force support point for the tie rod assemblies.

[0038] Multiple hinge seats 12 are evenly arranged around the central limiting member 1. The multiple hinge seats 12 are evenly distributed around the central limiting member 1 and face outward, serving as the connection hub between the central limiting member 1 and each adjustable pull rod assembly 2.

[0039] Figure 3The structure of the central limiting member 1 is shown. The central limiting member 1 is provided with a mounting portion 11. In some embodiments, the mounting portion 11 is located at the center of the central limiting member 1, and the mounting hole at the center facilitates preliminary alignment of the test piece (referred to as the control rod drive mechanism test piece) during assembly. The mounting portion 11 is a mounting hole arranged horizontally for fitting or fixing the top of the control rod drive mechanism under test. The horizontally arranged mounting hole facilitates fitting or fixing to the top of the test piece from a vertical direction.

[0040] Each adjustable pull rod assembly 2 has an adjustable length, with its inner end hinged to the corresponding hinge seat 12 and its outer end connected to the external fixing member 3. In some embodiments, such as Figure 1 As shown, multiple sets of adjustable tie rod assemblies 2 and central limiting components 1 are arranged on the same horizontal plane. This arrangement ensures that the constraint stiffness of the constraint device is consistent in all horizontal directions, and the constraint load forms a closed force transmission path in the horizontal plane.

[0041] In some embodiments, the number of adjustable tie rod assemblies 2 is four sets, which are symmetrically distributed at 90° intervals along the circumference of the central limiting member 1 to form a cross-shaped layout. The four sets of tie rod assemblies are respectively arranged in pairs along two mutually orthogonal horizontal directions, providing balanced constraint stiffness in the two orthogonal directions and forming a large torsional stiffness.

[0042] The embodiments in this specification are circumferentially uniformly symmetrically distributed and coplanarly arranged, ensuring consistent constraint stiffness in all directions and avoiding response bias caused by uneven stiffness. The four sets of 90° spaced cross-shaped layouts exhibit balanced performance in terms of horizontal bidirectional displacement constraint and torsional resistance, effectively preventing the test specimen from tilting and torsion under seismic loads. At the same time, the coplanar arrangement avoids additional moments caused by uneven heights, further improving the rationality of the force transmission path.

[0043] During assembly, the central limiting component 1 is first fitted onto the top support rod of the test piece via the mounting part 11; then, the inner ends of each set of adjustable tie rod assemblies 2 are hinged to the corresponding hinge seats 12, and the outer ends are connected to the external fixing component 3; the extension length of each set of adjustable tie rod assemblies 2 is adjusted to bring the central limiting component 1 to the predetermined center position; after adjustment, each set of tie rod assemblies is locked. During the test, multiple sets of tie rod assemblies jointly restrict the displacement of the test piece in the horizontal plane. When the seismic table undergoes slight attitude changes, the circumferential hinge structure between the adjustable tie rod assembly 2 and the central limiting component 1 allows the tie rod assembly to adjust its angle accordingly, so that the constraint force is mainly transmitted along the tie rod axis, reducing the influence of additional bending moment and lateral shear force on the test piece and threaded connection parts.

[0044] The embodiments in this specification replace traditional plate-type covering constraints with rod-system distributed force transmission constraints by using a central limiting component in conjunction with multiple sets of circumferentially evenly distributed hinged tie rod assemblies. This improves the force mode of the constraint device, reduces parasitic bending moments and lateral shear forces introduced by the out-of-plane warping deformation of the plate structure, and improves the accuracy of test data. At the same time, the adjustable length tie rod assemblies enable the device to adapt to test specimens of different specifications and different bench arrangements, improving its versatility.

[0045] In some embodiments, such as Figure 2 As shown, the central limiting member 1 has a disc-shaped structure. The disc-shaped central limiting member has good structural rigidity and geometric symmetry. The central limiting member 1 and the hinge seat 12 disposed on it can be integrally formed, or they can be formed separately and then fixed together. In some embodiments, the central limiting member 1 has a disc-shaped structure. The disc-shaped structure has uniform geometric characteristics in all radial directions, which is beneficial for balanced force transmission between the circumferentially evenly distributed hinge seats 12 and the adjustable tie rod assembly 2.

[0046] In some embodiments, such as Figure 3 As shown, the hinge seat 12 is a U-shaped fork lug seat, which has two fork arms spaced apart in its circumferential direction. The inner end of the adjustable pull rod assembly 2 is located between the two fork arms of the corresponding U-shaped fork lug seat. The two fork arms extend outward from the periphery of the central limiting member 1, forming a groove to accommodate the end of the pull rod assembly. The two fork arms of the U-shaped fork lug seat provide symmetrical support and limiting for the end of the pull rod assembly, which is beneficial for the uniform transmission of force at the hinge connection and improves the alignment and structural stability of the connection.

[0047] In some embodiments, such as Figure 1 As shown, each adjustable pull rod assembly 2 includes a pin and an adjusting screw 21. Figure 4 The structure of the adjusting screw 21 is shown. The adjusting screw is a long rod, the inner end of which is inserted between the two forks of the corresponding U-shaped fork lug, and is hinged to the U-shaped fork lug via a pin 22. The outer end of the adjusting screw is connected to the external fixing member 3.

[0048] In some embodiments, such as Figure 1 As shown, the inner end of the adjusting screw 21 is provided with a pin hole 211. The pin shaft 22 is laterally inserted into the two fork arms of the U-shaped fork lug and the pin hole 211 at the end of the adjusting screw 21, forming a hinge connection. The pin hole 211 is arranged along the vertical plane, that is, the axis of the pin hole 211 is along the horizontal direction and the through direction of the pin hole 211 is located in the vertical plane, so that the adjusting screw 21 can swing around the pin shaft 22 in the vertical plane.

[0049] The pin hinge allows the adjusting screw to swing around the pin when the attitude of the seismic station changes, automatically adapting to the angle change, so that the tension is always transmitted along the axis of the adjusting screw, avoiding bending stress and lateral shear force caused by rigid connection; the pin hole 211 is arranged along the vertical plane, which restricts the swing direction to the vertical plane, and maintains the horizontal constraint effect while adapting to pitch deflection.

[0050] In some embodiments, such as Figure 1 As shown, each adjustable rod assembly 2 also includes a locking nut group 23, which comprises at least two nuts. An external thread 212 is provided on the circumferential surface of the adjusting screw 21 near its outer end. At least two nuts are fitted onto the adjusting screw 21 and threadedly connected to it. The at least two nuts are located on the inner and outer sides of the external fixing member 3, respectively. The nuts located on the inner and outer sides of the external fixing member 3 form a bidirectional locking structure. By rotating the nuts, the extension length of the adjusting screw relative to the external fixing member 3 can be changed, and after adjustment, it is clamped and fixed from both sides.

[0051] In some embodiments, multiple sets of adjustable pull rod assemblies 2 are configured to independently adjust their extension lengths, and locking nut sets 23 are used to lock the corresponding adjusting screw after the extension length adjustment is completed. The operator can rotate each nut in turn to independently adjust the extension length of each adjusting screw, so that the center limiting member 1 moves precisely to the target center position; after all screws are adjusted to the correct position, each set of nuts is locked in both directions.

[0052] The embodiments in this specification achieve precise adjustment and reliable locking of the extension length of the adjusting screw through the double nut structure on the inner and outer sides of the external fixing component; the independent adjustment of each group allows the position of the central limiting component to be finely corrected on site, realizing the alignment of the seismic station, test piece and constraint device, reducing the collision risk and nonlinear error caused by installation eccentricity; the double nut locking structure has a good anti-loosening effect in vibration environment.

[0053] The basic concepts have been described above. It is clear that the detailed disclosure above is merely illustrative and does not constitute a limitation of this specification, especially for those skilled in the art. Furthermore, unless expressly stated in the claims, the order of elements and sequences, the use of numbers and letters, or other names in this specification are not intended to limit the order of the processes and methods described herein. Although various examples of currently considered useful embodiments of the invention have been discussed in the foregoing disclosure, it should be understood that such details are for illustrative purposes only, and the appended claims are not limited to the disclosed embodiments. Rather, the claims are intended to cover all modifications and equivalent combinations that conform to the substance and scope of the embodiments described herein.

Claims

1. A seismic test constraint device for a control rod drive mechanism, characterized in that, include: A central limiting member is configured to be fitted or fixed to the top of a control rod drive mechanism via an installation part, and a plurality of hinge seats are evenly arranged circumferentially on the central limiting member. Multiple sets of adjustable pull rod assemblies, the length of which is adjustable, the inner end of each set of adjustable pull rod assemblies is hinged to the corresponding hinge seat, and the outer end of each adjustable pull rod assembly is connected to an external fixing component; And external fixing components, which are configured as a fixing structure or reaction structure to connect to the seismic station; The adjustable tie rod assemblies are evenly distributed around the central limiting member.

2. The restraint device according to claim 1, characterized in that, The hinge seat is a U-shaped fork lug seat, which has two spaced-apart fork arms. The inner end of the adjustable pull rod assembly is located between the two fork arms of the corresponding U-shaped fork lug seat.

3. The restraint device according to claim 2, characterized in that, Each adjustable rod assembly includes a pin and an adjusting screw. The inner end of the adjusting screw is inserted between the two fork arms of the corresponding U-shaped fork lug and is hinged to the U-shaped fork lug via the pin. The outer end of the adjusting screw is connected to the external fixing member.

4. The restraint device according to claim 3, characterized in that, The inner end of the adjusting screw is provided with a pin hole, and the pin shaft is inserted through the pin hole and hinged to the U-shaped fork lug seat. The pin hole is arranged along the vertical plane.

5. The restraint device according to claim 3, characterized in that, Each adjustable rod assembly also includes a locking nut group, which includes at least two nuts that are threadedly connected to the adjusting screw and are located on the inner and outer sides of the external fixing member, respectively.

6. The restraint device according to claim 5, characterized in that, Each of the multiple adjustable pull rod assemblies is configured to independently adjust the extension length, and the locking nut assembly is used to lock the adjusting screw after the corresponding adjusting screw has completed the extension length adjustment.

7. The restraint device according to claim 1, characterized in that, The central limiting member is a disc-shaped structure, and its mounting part is located at the center of the central limiting member.

8. The restraint device according to claim 7, characterized in that, The mounting part is a mounting hole, which is arranged in a horizontal direction.

9. The restraint device according to claim 1, characterized in that, Multiple sets of the adjustable tie rod assemblies are evenly and symmetrically distributed along the circumference of the central limiting member, and the multiple sets of the adjustable tie rod assemblies and the central limiting member are arranged on the same horizontal plane, so that the constraint stiffness of the constraint device is consistent in all horizontal directions.

10. The restraint device according to claim 9, characterized in that, The number of adjustable pull rod assemblies is four, and the four sets of adjustable pull rod assemblies are symmetrically distributed at 90° intervals along the circumference of the central limiting member.

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