Limit device and drive mechanism for control rod drive mechanism of high-temperature gas-cooled reactor

Abstract

The present invention provides a limit device and a drive mechanism for a control rod drive mechanism of a high-temperature gas-cooled reactor, including a main body, a transmission gear, a lead screw, a first electrode, a second electrode and a third electrode; the transmission gear is arranged inside the main body, the lead screw is arranged at the output end of the transmission gear, and the transmission gear is configured to rotate under the drive of a drive assembly and drive the lead screw to rotate; the first electrode is arranged at a preset position of the lead screw; the second electrode is arranged on the lead screw and moves towards the preset position under the rotation drive of the lead screw; the third electrode is detachably arranged inside the main body and close to the preset position. One technical effect of the present invention is that the structure is reasonably designed, can accurately limit the movement of the control rod, and ensures the reliable and stable operation of the drive mechanism.

Description

Technical Field

[0001] The present invention belongs to the technical field of high-temperature gas-cooled reactors, and particularly relates to a limit device and a drive mechanism for a control rod drive mechanism of a high-temperature gas-cooled reactor. Background Art

[0002] The control rod drive mechanism of a high-temperature gas-cooled reactor is a reactor control actuator designed according to the technical characteristics of a high-temperature gas-cooled reactor. Its function is to accurately execute the commands of the reactor control system to precisely lift and lower the control rods. The role of the limit device is to reflect the upper limit of the control rod lift and the lower limit of the control rod insertion.

[0003] For example, when the control rod is lifted to the upper limit, the limit device provides an upper limit signal to the control system, thereby locking the control rod lifting function of the DCS (Distributed Control System), and at the same time, the upper limit indicator light on the mimic panel lights up to prevent damage to the mechanical structure of the control rod system when the control rod is lifted beyond its stroke range. By the same principle, when the control rod is inserted to the lower limit, a lower limit signal is provided to lock the control rod insertion function of the DCS and prevent damage to the mechanical structure of the control rod system when the control rod is inserted beyond its stroke range.

[0004] However, the current limit device has an unreasonable structural design. Under high temperature, high pressure and long-term compression states, mechanical structure damage and node adhesion failures will occur, resulting in the DCS being unable to normally lift and insert the control rods, thus increasing the difficulty of maintenance work for the drive mechanism. Summary of the Invention

[0005] The present invention aims to at least solve one of the technical problems existing in the prior art, and provides a new technical solution for a limit device and a drive mechanism for a control rod drive mechanism of a high-temperature gas-cooled reactor.

[0006] According to a first aspect of the present invention, there is provided a limit device for a control rod drive mechanism of a high-temperature gas-cooled reactor, including:

[0007] A main body;

[0008] A transmission gear and a lead screw, the transmission gear is arranged inside the main body, the lead screw is arranged at the output end of the transmission gear, and the transmission gear is configured to rotate under the drive of a drive assembly and drive the lead screw to rotate;

[0009] A first electrode, a second electrode and a third electrode, the first electrode is arranged at a preset position of the lead screw; the second electrode is arranged on the lead screw and moves towards the preset position under the drive of the rotation of the lead screw; the third electrode is detachably arranged inside the main body and close to the preset position;

[0010] When the second electrode moves towards the preset position, the second electrode contacts and presses the third electrode, and then the second electrode contacts the first electrode. The first electrode is conducted through the second electrode and the third electrode to provide a limit signal to the driving mechanism.

[0011] Optionally, the preset position includes a first preset position and a second preset position, and the first preset position and the second preset position are respectively located at opposite ends of the lead screw.

[0012] Two of the first electrodes are respectively located at the first preset position and the second preset position. Two of the second electrodes are both arranged in the middle of the lead screw and correspond to the two first electrodes one by one. Two of the third electrodes are respectively close to the first preset position and the second preset position.

[0013] When the lead screw rotates in the first direction, one of the second electrodes moves towards the first preset position. The first electrode located at the first preset position is conducted through the second electrode and the third electrode close to the first preset position to provide a first limit signal to the driving mechanism.

[0014] When the lead screw rotates in the second direction, the other second electrode moves towards the second preset position. The first electrode located at the second preset position is conducted through the second electrode and the third electrode close to the second preset position to provide a second limit signal to the driving mechanism.

[0015] Optionally, the first electrode located at the first preset position is an upper limit electrode, and the first limit signal is an upper limit signal; the first electrode located at the second preset position is a lower limit electrode, and the second limit signal is a lower limit signal.

[0016] When the upper limit electrode is conducted with the third electrode, an upper limit signal is provided to the driving mechanism.

[0017] When the lower limit electrode is conducted with the third electrode, a lower limit signal is provided to the driving mechanism.

[0018] Optionally, the limit device for the control rod drive mechanism of the high-temperature gas-cooled reactor further includes:

[0019] A guide rod, the guide rod is arranged inside the main body, and the guide rod is arranged parallel to the lead screw; the third electrode is detachably arranged on the guide rod.

[0020] Optionally, the third electrode includes an insulating housing, a spring, a conductive rod and a conductive key.

[0021] The insulating housing is fixed to the conductive rod. The spring is disposed within the insulating housing, with one end of the spring connected to the conductive rod and the other end connected to the insulating housing. The end of the conductive rod remote from the spring extends outside the insulating housing and is fixedly connected to the conductive key, and the conductive rod is connected to a wire.

[0022] When the second electrode moves towards the preset position, the second electrode contacts the conductive key and compresses the spring.

[0023] Optionally, the third electrode further includes a wire pressing bolt, a first fixing bolt, a clamping member, a clamping bolt, and a second fixing bolt.

[0024] The wire pressing bolt is fixed to the end of the conductive rod near the spring, and the wire is electrically connected to the wire pressing bolt. The spring is fixed to the conductive rod through the wire pressing bolt, and the first fixing bolt fixes the spring to the insulating housing. The clamping member and the insulating housing cooperate to form a mounting hole, the guide rod passes through the mounting hole, and the clamping bolt fixes the clamping member to the insulating housing. The second fixing bolt fixes the conductive key to the conductive rod.

[0025] Optionally, the surface of the conductive key near the second electrode protrudes from the surface of the first electrode near the second electrode.

[0026] Optionally, a guide key extending along the length direction of the conductive rod is provided on the outer surface of the conductive rod. A guide groove matching with the guide key is provided on the inner surface of the insulating housing, and the guide key is embedded in the guide groove.

[0027] According to the second aspect of the present invention, a driving mechanism is provided, including:

[0028] The above-mentioned limiting device;

[0029] A driving component, the driving component includes a stepping motor and a coupling, and the transmission gear is installed on the first output end of the stepping motor through the coupling.

[0030] A speed reduction component, the speed reduction component is installed on the second output end of the stepping motor.

[0031] A chain unit, one end of the chain unit is fixed to the output end of the speed reduction component, and the other end is fixed to the control rod.

[0032] The stepping motor rotates to drive the chain unit to wind or unwind on the output end of the speed reduction component, so as to lift or lower the control rod.

[0033] Optionally, the driving mechanism further includes:

[0034] Eddy current speed limiter, and the eddy current speed limiter is arranged on the deceleration component;

[0035] In the case where the stepping motor loses power, the eddy current speed limiter is used to reduce the descending speed of the control rod.

[0036] One technical effect of the present invention is that:

[0037] In the embodiment of the present application, the transmission gear is arranged inside the main body, the lead screw is arranged at the output end of the transmission gear, and the first electrode is arranged at a preset position of the lead screw; the second electrode is arranged on the lead screw and moves towards the preset position under the rotation drive of the lead screw; the third electrode is detachably arranged inside the main body and close to the preset position. The transmission gear rotates under the drive of the drive assembly and drives the lead screw to rotate, thereby driving the second electrode to move towards the preset position, so that the second electrode contacts and presses the third electrode, and then the second electrode contacts the first electrode. Therefore, the first electrode is conducted through the second electrode and the third electrode to form a closed node, so as to provide a limit signal to the control system, lock the control rod lifting function or the control rod inserting function of the DCS, and at the same time, the indicator light on the mimic panel lights up, preventing the control rod from exceeding its stroke range and causing damage to the mechanical structure of the control rod system.

[0038] Therefore, the limit device can not only accurately limit the movement of the control rod, with high safety, but also effectively prevent the limit device from having mechanical structure damage and node adhesion faults, ensuring the safe and stable operation of the drive mechanism. Description of the Drawings

[0039] Figure 1 Structural schematic diagram of a drive mechanism according to an embodiment of the present invention;

[0040] Figure 2 Structural schematic diagram of a limit device for a control rod drive mechanism of a high-temperature gas-cooled reactor according to an embodiment of the present invention;

[0041] Figure 3 Structural schematic diagram of a third electrode of a limit device for a control rod drive mechanism of a high-temperature gas-cooled reactor according to an embodiment of the present invention.

[0042] In the figure:

[0043] 100, limit device; 200, drive assembly; 201, stepping motor; 202, coupling; 300, deceleration component; 400, resolver; 500, chain unit; 600, chain storage box; 700, eddy current speed limiter;

[0044] 1. Main body; 2. Transmission gear; 3. Lead screw; 31. First preset position; 32. Second preset position; 4. First electrode; 5. Second electrode; 6. Third electrode; 61. Insulating housing; 62. Spring; 63. Conductive rod; 64. Conductive key; 65. Pressing bolt; 66. First fixing bolt; 67. Clamping member; 68. Clamping bolt; 69. Second fixing bolt; 7. Guide rod. Detailed implementation manners

[0045] Now, various exemplary embodiments of the present application will be described in detail with reference to the accompanying drawings. It should be noted that: unless otherwise specifically stated, the relative arrangements, numerical expressions, and numerical values of the components and steps set forth in these embodiments do not limit the scope of the present application.

[0046] The embodiments of the present application will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals indicate the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary only for explaining the present application and should not be construed as a limitation of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts fall within the scope of protection of the present application.

[0047] The terms "first" and "second" in the description and claims of the present application may explicitly or implicitly include one or more of such features. In the description of the present application, unless otherwise specified, the meaning of "a plurality" is two or more. In addition, "and / or" in the description and claims means at least one of the connected objects, and the character " / " generally means an "or" relationship between the associated objects before and after.

[0048] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present application.

[0049] In the description of the present application, it should be noted that unless otherwise clearly specified and defined, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0050] As Figure 2 and Figure 3 shown, according to the first aspect of the present invention, a limiting device 100 for a control rod drive mechanism of a high-temperature gas-cooled reactor is provided, which can accurately limit the control rod drive mechanism of the high-temperature gas-cooled reactor.

[0051] Specifically, the limiting device 100 for the control rod drive mechanism of the high-temperature gas-cooled reactor includes a main body 1, a transmission gear 2, a lead screw 3, a first electrode 4, a second electrode 5, and a third electrode 6. Among them, the main body 1 is used to carry structures such as the transmission gear 2, the lead screw 3, the first electrode 4, and the second electrode 5, and can also better protect the transmission gear 2, the lead screw 3, the first electrode 4, the second electrode 5, etc.

[0052] More specifically, the transmission gear 2 is arranged inside the main body 1, the lead screw 3 is arranged at the output end of the transmission gear 2, and the transmission gear 2 is configured to rotate under the drive of a drive assembly 200 and drive the lead screw 3 to rotate. At the same time, the lead screw 3 can also indirectly reflect the situation of the drive assembly 200 driving the control rod to move.

[0053] See Figure 1 , the first electrode 4 is arranged at a preset position of the lead screw 3; the second electrode 5 is arranged on the lead screw 3 and moves towards the preset position under the rotational drive of the lead screw 3; the third electrode 6 is detachably arranged inside the main body

[0054] 1 and close to the preset position.

[0055] It should be noted that the preset position can correspond to the upper limit position of the control rod lift. That is, when the control rod is lifted to the upper limit position by the drive assembly 200, the drive assembly 200 drives the lead screw 3 to rotate, thereby driving the second electrode 5 to move towards the preset position until it presses against the first electrode 4, so as to realize the conduction of the first electrode 4, the second electrode 5, and the third electrode 6, and provide a limit signal to the drive mechanism, then the drive assembly 200 stops lifting the control rod. At this time, the position where the control rod is located is the upper limit position of the control rod, and the position where the second electrode 5 is located is the upper limit position of the limiting device 100.

[0056] Similarly, the preset position can correspond to the lower limit position of the control rod insertion. That is, when the control rod is inserted to the lower limit position by the driving assembly 200, the driving assembly 200 drives the lead screw 3 to rotate, and then drives the second electrode 5 to move towards the preset position until it presses against the first electrode 4, so as to realize the conduction of the first electrode 4, the second electrode 5, and the third electrode 6, and provide a limit signal to the driving mechanism, then the driving assembly 200 stops inserting the control rod. At this time, the position of the control rod is the lower limit position of the control rod, and the position of the second electrode 5 is the lower limit position of the limiting device 100.

[0057] Of course, two different preset positions can also be set respectively corresponding to the upper limit position and the lower limit position of the control rod, so that the limiting device 100 can not only limit the upper limit position of the control rod, but also limit the lower limit position of the control rod.

[0058] When the second electrode 5 moves towards the preset position, the second electrode 5 contacts and presses the third electrode 6, and then the second electrode 5 contacts the first electrode 4, and the first electrode 4 is conducted through the second electrode 5 and the third electrode 6 to provide a limit signal to the driving mechanism.

[0059] In the embodiment of the present application, the transmission gear 2 is arranged inside the main body 1, the lead screw 3 is arranged at the output end of the transmission gear 2, the first electrode 4 is arranged at the preset position of the lead screw 3; the second electrode 5 is arranged on the lead screw 3 and moves towards the preset position under the rotation drive of the lead screw 3; the third electrode 6 is detachably arranged inside the main body 1 and close to the preset position. The transmission gear 2 rotates under the drive of the driving assembly 200 and drives the lead screw 3 to rotate, and then drives the second electrode 5 to move towards the preset position, so that the second electrode 5 contacts and presses the third electrode 6, and then the second electrode 5 contacts the first electrode 4. Therefore, the first electrode 4 is conducted through the second electrode 5 and the third electrode 6 to form a closed node, so as to provide a limit signal to the control system, lock the control rod lifting function or the control rod insertion function of the DCS, and at the same time, the indicator light on the mimic panel lights up to prevent the control rod from exceeding its stroke range and damaging the mechanical structure of the control rod system.

[0060] Therefore, the limiting device 100 can not only accurately limit the movement of the control rod, with high safety, but also effectively prevent the limiting device 100 from having mechanical structure damage and node adhesion faults, ensuring the safe and stable operation of the driving mechanism.

[0061] Optionally, the preset position includes a first preset position 31 and a second preset position 32, and the first preset position 31 and the second preset position 32 are respectively located at opposite ends of the lead screw 3.

[0062] The two first electrodes 4 are respectively located at the first preset position 31 and the second preset position 32. The two second electrodes 5 are both arranged in the middle of the lead screw 3 and correspond to the two first electrodes 4 one by one. The two third electrodes 6 are respectively close to the first preset position 31 and the second preset position 32. An insulating partition is arranged between the two second electrodes 5 to better protect the second electrodes 5 and effectively prevent electrical connection between the two second electrodes 5.

[0063] When the lead screw 3 rotates in the first direction, one of the second electrodes 5 moves towards the first preset position 31. The first electrode 4 located at the first preset position 31 is conducted through the second electrode 5 with the third electrode 6 close to the first preset position 31 to provide a first limit signal to the driving mechanism.

[0064] When the lead screw 3 rotates in the second direction, the other second electrode 5 moves towards the second preset position 32. The first electrode 4 located at the second preset position 32 is conducted through the second electrode 5 with the third electrode 6 close to the second preset position 32 to provide a second limit signal to the driving mechanism.

[0065] In the above embodiment, by controlling the rotation direction of the lead screw 3, it is possible to control the second electrode 5 to move towards the corresponding first electrode 4 to achieve conduction of the first motor, the second electrode 5 and the third electrode 6, that is, different limit signals can be provided to the driving mechanism, so as to stop lifting the control rod or stop inserting the control rod downward. This enables the limit device 100 to accurately limit the movement of the control rod and ensures the reliable and stable operation of the driving mechanism.

[0066] Optionally, the first electrode 4 located at the first preset position 31 is an upper limit electrode, and the first limit signal is an upper limit signal; the first electrode 4 located at the second preset position 32 is a lower limit electrode, and the second limit signal is a lower limit signal;

[0067] When the upper limit electrode is conducted with the third electrode 6, an upper limit signal is provided to the driving mechanism;

[0068] When the lower limit electrode is conducted with the third electrode 6, a lower limit signal is provided to the driving mechanism.

[0069] In the above embodiment, the upper limit electrode is electrically connected to the third electrode 6 to provide an upper limit signal to the drive mechanism; the lower limit electrode is electrically connected to the third electrode 6 to provide a lower limit signal to the drive mechanism. By rotating the lead screw 3 in different directions, different second electrodes 5 are driven to move, so that the upper limit electrode is electrically connected to the corresponding first electrode 4, or the lower limit electrode is electrically connected to the corresponding first electrode 4. This not only has a simple structure and is easy to operate, but also can stably provide a limit signal to the drive mechanism, thereby accurately limiting the movement of the control rod and being beneficial to better protecting the drive mechanism.

[0070] Optionally, the limit device 100 for the control rod drive mechanism of the high-temperature gas-cooled reactor further includes:

[0071] A guide rod 7, the guide rod 7 is disposed inside the main body 1, and the guide rod 7 is arranged in parallel with the lead screw 3; the third electrode 6 is detachably disposed on the guide rod 7.

[0072] In the above embodiment, the guide rod 7 is disposed inside the main body 1, which is beneficial to quickly and stably fixing the third electrode 6 on the guide rod 7, facilitating assembly and also facilitating ensuring the stability of the connection between the first electrode 4, the second electrode 5, and the third electrode 6.

[0073] Optionally, the third electrode 6 includes an insulating housing 61, a spring 62, a conductive rod 63, and a conductive key 64;

[0074] The insulating housing 61 is fixed to the conductive rod 63, the spring 62 is disposed inside the insulating housing 61, and one end of the spring 62 is connected to the conductive rod 63 and the other end is connected to the insulating housing 61; the end of the conductive rod 63 away from the spring 62 extends outside the insulating housing 61 and is fixedly connected to the conductive key 64, and the conductive rod 63 is connected to a wire;

[0075] When the second electrode 5 moves toward the preset position, the second electrode 5 contacts the conductive key 64 and compresses the spring 62.

[0076] In the above embodiment, the structural design of the third electrode 6 is reasonable, which is beneficial to realizing the stable connection between the second electrode 5 and the third electrode 6 through the conductive key 64 when the second electrode 5 moves, and further realizing the electrical connection of the first electrode 4, the second electrode 5, and the third electrode 6.

[0077] For example, the conductive key 64, the conductive rod 63, and the pressure bolt 65 are all made of pure copper (T1) with good electrical conductivity; the insulating housing 61 and the clamping member 67 are both made of engineering plastic (PEEK-GF30) with high temperature resistance and good insulation performance. The first fixing bolt 66 and the second fixing bolt 69 are both made of low-carbon alloy steel. This makes the structure of the third electrode 6 more stable and helps to achieve stable connections between the third electrode 6, the second electrode 5, and the first electrode 4.

[0078] Optionally, referring to Figure 3 , the third electrode 6 further includes a pressure bolt 65, a first fixing bolt 66, a clamping member 67, a clamping bolt 68, and a second fixing bolt 69;

[0079] The pressure bolt 65 is fixed to one end of the conductive rod 63 close to the spring 62, and the wire is electrically connected to the pressure bolt 65; and the spring 62 is fixed to the conductive rod 63 through the pressure bolt 65, and the first fixing bolt 66 fixes the spring 62 to the insulating housing 61; the clamping member 67 and the insulating housing 61 cooperate to form a mounting hole, the guide rod 7 passes through the mounting hole, and the clamping bolt 68 fixes the clamping member 67 to the insulating housing 61; the second fixing bolt 69 fixes the conductive key 64 to the conductive rod 63.

[0080] In the above embodiment, one end of the spring 62 can be firmly fixed to the insulating housing 61 through the first fixing bolt 66, so that the spring 62 can better buffer the movement of the conductive rod 63 and can better protect the third electrode 6. The clamping bolt 68 fixes the clamping member 67 to the insulating housing 61, which can achieve quick installation and disassembly of the third electrode 6 to the guide rod 7, the operation is very convenient, and it is also easy to stably fix the third electrode 6 on the guide rod 7. The second fixing bolt 69 fixes the conductive key 64 to the conductive rod 63, so that when the second electrode 5 presses the third electrode 6, it can maintain a good connection with the third electrode 6, which helps to achieve stable conduction of the first electrode 4 through the second electrode 5 to the third electrode 6 to provide an accurate limit signal to the driving mechanism.

[0081] It should be noted that when installing the third electrode 6, only after it is determined that the second electrode 5, the first electrode 4, and the second electrode 5 can be reliably connected, then the clamping bolt 68 is tightened to firmly fix the third electrode 6 on the guide rod 7.

[0082] Optionally, the surface of the conductive key 64 close to the second electrode 5 protrudes from the surface of the first electrode 4 close to the second electrode 5. This is conducive to the second electrode 5 contacting the third electrode 6 first when moving. When the second electrode 5 continues to move, it will squeeze the third electrode 6 until it contacts the first electrode 4, which can better achieve the conduction between the first electrode 4, the second electrode 5, and the third electrode 6, thereby facilitating the provision of an accurate limit signal to the drive mechanism.

[0083] Optionally, a guiding key extending along the length direction of the conductive rod 63 is provided on the outer surface of the conductive rod 63; a guiding groove matching with the guiding key is provided on the inner surface of the insulating housing 61, and the guiding key is embedded in the guiding groove.

[0084] In the above embodiment, the cooperation between the conductive rod 63 and the insulating housing 61 is a key connection, which effectively prevents the conductive rod 63 from rotating relative to the insulating housing 61 during the movement, ensuring that the second electrode 5 is always stably connected to the third electrode 6 through the conductive key 64 during the movement.

[0085] According to the second aspect of the present invention, as Figure 1 shown, a drive mechanism is provided, including:

[0086] The above-mentioned limiting device 100;

[0087] A drive assembly 200, the drive assembly 200 includes a stepping motor 201 and a coupling 202, and the transmission gear 2 is installed on the first output end of the stepping motor 201 through the coupling 202. The drive assembly 200 is used to drive the control rod to move, and is also used to drive the transmission gear 2 in the limiting device 100 to rotate, so as to accurately limit the movement of the control rod.

[0088] A deceleration assembly 300, the deceleration assembly 300 is installed on the second output end of the stepping motor 201, and the deceleration assembly 300 is used to decelerate the stepping motor 201 to ensure the safe, stable and uniform movement of the control rod.

[0089] A chain unit 500, one end of the chain unit 500 is fixed to the output end of the deceleration assembly 300, and the other end is fixed to the control rod. The chain unit 500 is used to fix the control rod, and the drive assembly 200 drives the chain unit 500 to move, and further drives the control rod to move through the movement of the chain unit 500, which helps to ensure the stability of the movement of the control rod.

[0090] The stepping motor 201 rotates to drive the chain unit 500 to wind or unwind around the output end of the deceleration assembly 300, so as to lift or insert the control rod, thereby enabling better control of the movement of the control rod.

[0091] In the above - mentioned embodiment, the drive structure is reasonably designed and has a simple structure. It can only accurately limit the movement of the control rod, with high safety. Moreover, it effectively prevents the limiting device 100 from suffering mechanical structure damage and node adhesion failures, ensuring the safe and stable operation of the drive mechanism.

[0092] Optionally, the drive mechanism further includes:

[0093] An eddy - current speed limiter 700, and the eddy - current speed limiter 700 is arranged on the reduction assembly 300;

[0094] When the stepping motor 201 loses power, the eddy - current speed limiter 700 is used to reduce the descending speed of the control rod, thereby reducing the impact on the drive mechanism caused by the control rod falling when power is cut off. Thus, it can better protect the control rod and the drive mechanism, ensuring the stability of the overall operation of the drive mechanism.

[0095] Optionally, the drive mechanism further includes a resolver 400 for measuring the position of the control rod, and the resolver 400 is arranged on the reduction assembly 300. During the process of the stepping motor 201 driving the control rod to lift (insert downward), the resolver 400 can reflect the height of the control rod position. At the same time, the control rod position measurement system provides upper - limit and lower - limit alarms for the operator's reference, making the movement of the control rod safer.

[0096] In a specific embodiment, when lifting the control rod, the stepping motor 201 drives the transmission gear 2 to rotate, the transmission gear 2 drives the lead screw 3 to rotate. When the lead screw 3 drives the second electrode 5 to reach the upper - limit position, it first presses the third electrode 6, and then presses the first electrode 4 to form a limit switch and ensure reliable pressing of the first electrode 4, the second electrode 5, and the third electrode 6, thereby sending out the upper - limit signal. Then, when inserting the control rod downward, the lead screw 3 drives the second electrode 5 to move and disconnect from the first electrode 4 and the third electrode 6, and the upper - limit signal is no longer sent. The lower - limit signal is sent out in the same principle. This application relies on the second electrode 5 to bridge a path between the first electrode 4 and the third electrode 6, which can be reliably separated and combined, eliminating the hidden dangers of mechanical structure damage and node adhesion of traditional travel switches.

[0097] In this application, the transmission process of the drive mechanism is as follows:

[0098] The positive (reverse) rotation of the stepping motor 201 is controlled by the control system, and then the power is transmitted to the chain unit 500 through the reduction assembly 300, and the chain unit 500 lifts (inserts downward) the control rod. For example, the chain - socket gear is arranged on the output shaft of the reduction assembly 300, and the reduction assembly 300 can drive the chain - socket gear to rotate, thereby driving the chain unit 500 fixed to the chain - socket gear to move, and then driving the control rod to move to better control the reactivity of the reactor.

[0099] For example, the endless chain unit 500 lifted by the chain socket gear is stored in the chain storage box 600, so that the endless chain unit 500 can be better protected.

[0100] The transmission process of the limit device 100 is as follows:

[0101] The stepping motor 201 drives the control rod to lift (lower insert). The stepping motor 201 drives the transmission gear 2 to rotate through the coupling 202. The transmission gear 2 drives the lead screw 3 to rotate. The lead screw 3 drives the second electrode 5 to move to the upper limit (lower limit), and conducts with the first electrode 4 and the third electrode 6, so as to send out the upper limit (lower limit) node, in order to better control the upper limit and the lower limit of the control rod.

[0102] Therefore, the limit device and the drive mechanism can ensure the reliable and stable operation of the control rod system, reduce the difficulty of maintenance work, and improve the work efficiency.

[0103] It can be understood that the above embodiments are only exemplary embodiments adopted to illustrate the principle of the present invention. However, the present invention is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also regarded as the protection scope of the present invention.

Claims

1. A limit device for a control rod drive mechanism of a high-temperature gas-cooled reactor, characterized in that, Comprising: A main body; A transmission gear and a lead screw, the transmission gear is arranged inside the main body, the lead screw is arranged at the output end of the transmission gear, and the transmission gear is configured to rotate under the drive of a drive assembly and drive the lead screw to rotate; A first electrode, a second electrode and a third electrode, the first electrode is arranged at a preset position of the lead screw; the second electrode is arranged on the lead screw and moves towards the preset position under the rotational drive of the lead screw; the third electrode is detachably arranged inside the main body and close to the preset position; When the second electrode moves towards the preset position, the second electrode contacts and presses the third electrode, and then the second electrode contacts the first electrode, and the first electrode is conducted to the third electrode through the second electrode to provide a limit signal to the drive mechanism.

2. The position-limiting device for the control rod drive mechanism of a high-temperature gas-cooled reactor according to claim 1, wherein The preset position includes a first preset position and a second preset position, the first preset position and the second preset position are respectively located at opposite ends of the lead screw; Two of the first electrodes are respectively located at the first preset position and the second preset position, two of the second electrodes are both arranged in the middle of the lead screw and correspond to the two first electrodes one by one, and two of the third electrodes are respectively close to the first preset position and the second preset position; When the lead screw rotates in a first direction, one of the second electrodes moves towards the first preset position, and the first electrode located at the first preset position is conducted to the third electrode close to the first preset position through the second electrode to provide a first limit signal to the drive mechanism; When the lead screw rotates in a second direction, the other second electrode moves towards the second preset position, and the first electrode located at the second preset position is conducted to the third electrode close to the second preset position through the second electrode to provide a second limit signal to the drive mechanism.

3. The limit device for the control rod drive mechanism of a high-temperature gas-cooled reactor according to claim 2, characterized in that, The first electrode located at the first preset position is an upper limit electrode, and the first limit signal is an upper limit signal; the first electrode located at the second preset position is a lower limit electrode, and the second limit signal is a lower limit signal; When the upper limit electrode is conducted to the third electrode, an upper limit signal is provided to the drive mechanism; When the lower limit electrode is conducted to the third electrode, a lower limit signal is provided to the drive mechanism.

4. The position-limiting device for the control rod drive mechanism of a high-temperature gas-cooled reactor according to claim 1, characterized in that, Further comprising: A guide rod, the guide rod is arranged inside the main body, and the guide rod is arranged parallel to the lead screw; the third electrode is detachably arranged on the guide rod.

5. The position-limiting device for the control rod drive mechanism of a high-temperature gas-cooled reactor according to claim 4, characterized in that, The third electrode includes an insulating housing, a spring, a conductive rod and a conductive key; The insulating housing is fixed to the conductive rod, the spring is arranged inside the insulating housing, one end of the spring is connected to the conductive rod, and the other end is connected to the insulating housing; the end of the conductive rod away from the spring extends to the outside of the insulating housing and is fixedly connected to the conductive key, and the conductive rod is connected to a wire; When the second electrode moves towards the preset position, the second electrode contacts and presses the conductive key and the spring.

6. The limit device for the control rod drive mechanism of a high-temperature gas-cooled reactor according to claim 5, characterized in that, The third electrode further includes a pressure wire bolt, a first fixing bolt, a clamping member, a clamping bolt and a second fixing bolt; The wire pressing bolt is fixed to one end of the conductive rod close to the spring, and the wire is electrically connected to the wire pressing bolt; and the spring is fixed to the conductive rod through the wire pressing bolt, and the first fixing bolt fixes the spring to the insulating housing; the clamping member and the insulating housing cooperate to form a mounting hole, the guide rod is disposed through the mounting hole, and the clamping bolt fixes the clamping member to the insulating housing; the second fixing bolt fixes the conductive key to the conductive rod.

7. The position-limiting device for a control rod drive mechanism of a high-temperature gas-cooled reactor according to claim 5, wherein The surface of the conductive key close to the second electrode protrudes from the surface of the first electrode close to the second electrode.

8. The position-limiting device for a control rod drive mechanism of a high-temperature gas-cooled reactor according to claim 5, wherein A guide key extending along the length direction of the conductive rod is disposed on the outer surface of the conductive rod; a guide groove cooperating with the guide key is disposed on the inner surface of the insulating housing, and the guide key is embedded in the guide groove.

9. A driving mechanism, characterized in that, Comprising: The position-limiting device according to any one of claims 1-5; A drive assembly, the drive assembly includes a stepper motor and a coupling, and the transmission gear is mounted on the first output end of the stepper motor through the coupling; A speed reduction assembly, the speed reduction assembly is mounted on the second output end of the stepper motor; A chain unit, one end of the chain unit is fixed to the output end of the speed reduction assembly, and the other end is fixed to the control rod; The stepper motor rotates to drive the chain unit to wind or unwind around the output end of the speed reduction assembly, so as to lift or lower the control rod.

10. The drive mechanism according to claim 9, characterized in that, Further comprising: An eddy current speed limiter, the eddy current speed limiter is disposed on the speed reduction assembly; In the case where the stepper motor loses power, the eddy current speed limiter is used to reduce the descending speed of the control rod.

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