A pebble bed high temperature gas cooled reactor fuel element counting device and method

Abstract

The application provides a kind of pebble bed high temperature gas cooled reactor fuel element counting device and method, fuel element counting device includes ball flow pipeline, first counting unit and second counting unit;The ball flow pipeline includes sequentially connected first pipeline, flow guide pipeline and second pipeline;The first counting unit is arranged in the first pipeline, for the first time counting to the spherical element passing through the first pipeline;The second counting unit includes buffer and pressure sensor, the buffer is movably arranged on the inner surface of the flow guide pipeline, the pressure sensor is arranged in the buffer, when the spherical element passing through the first pipeline falls on the buffer, the pressure that the spherical element acts on the buffer is measured by the pressure sensor, according to the measured value, the spherical element passing through the flow guide pipeline is counted second time.The technical effect of the application is that the measurement range is larger, and the measurement result is accurate.

Description

Technical Field

[0001] This invention belongs to the field of nuclear power technology, specifically relating to a counting device and method for fuel elements in a pebble bed type high-temperature gas-cooled reactor. Background Technology

[0002] The pebble bed high-temperature gas-cooled reactor (PBT) employs a continuous online refueling method without reactor shutdown. The number of fuel elements loaded, unloaded, and circulated is primarily detected and counted by fuel element counters (hereinafter referred to as pebble counters) on the pebble flow pipes of the fuel loading and unloading system. The pebble counter is a key sensing device in the PBT fuel loading and unloading system for automating fuel element circulation and transport. Its main function is to accurately judge, count, and record the dynamic information of fuel elements in each pebble flow pipe and storage container in real time, and to transmit key information to the main control system. Furthermore, the pebble counter is also a crucial measuring device for nuclear material balance calculations. While the number of fuel elements can be manually counted during loading, once the fuel elements enter the fuel loading and unloading system, the pebble counter is almost the only device for measuring the number of fuel elements.

[0003] The sphere counters currently used in the completed High-Temperature Gas-Cooled Reactor (HTR-PM) nuclear power plant demonstration project are eddy current counters. Their basic principle is to monitor the passage of fuel elements using eddy current signals from eddy current sensors surrounding the sphere tube wall. However, in actual operation, eddy current sphere counters are prone to miscounting (mainly undercounting), affecting the normal operation of the fuel loading and unloading system. Undercounting in some critical sphere counters can even lead to the reactor entering operational limitation conditions. Furthermore, from the perspective of nuclear material balance, a physical inventory of fuel elements should be conducted at the end of the nuclear material balance cycle. Currently, the fuel loading and unloading system only uses sphere counters to measure the number of fuel elements, and measurement errors frequently occur, easily leading to MUF (Material Unaccounted For), thus causing difficulties in MUF evaluation. Moreover, the measurement range of eddy current sphere counters is also limited; the fuel element velocity must be within a certain range, and the size of the damaged fuel elements that can be measured must be larger than a certain limit.

[0004] In addition, some domestic and international institutions are researching sphere counters based on the principle of radiation detection. Unirradiated fuel elements have a certain degree of radioactivity, while irradiated fuel elements have significantly increased radioactivity. Therefore, the number of fuel elements can be measured by detecting the radiation level. However, this method requires the fuel elements to remain in the measuring device for a period of time, which may affect the operation of the fuel loading and unloading system, and it cannot measure the graphite spheres used in the initial core loading. Summary of the Invention

[0005] The present invention aims to at least solve one of the technical problems existing in the prior art, and to provide a new technical solution for a fuel element counting device and method for a pebble bed type high-temperature gas-cooled reactor.

[0006] According to a first aspect of the embodiments of this application, a pebble bed type high-temperature gas-cooled reactor fuel element counting device is provided, comprising:

[0007] A ball flow pipeline, comprising a first pipeline, a guide pipeline, and a second pipeline connected in sequence, wherein a spherical element can pass through the first pipeline, the guide pipeline, and the second pipeline in sequence;

[0008] A first counting unit is disposed in the first pipeline and is used to perform a first count on the spherical element passing through the first pipeline;

[0009] The second counting unit includes a buffer and a pressure sensor. The buffer is movably disposed on the inner surface of the flow guide pipe, and the pressure sensor is disposed on the buffer. When the spherical element passing through the first pipe falls on the buffer, the pressure sensor measures the pressure exerted by the spherical element on the buffer, and performs a second count on the spherical element passing through the flow guide pipe based on the measured value.

[0010] The results of the first and second counts are compared to verify the number of balls passing through the ball flow pipeline.

[0011] Optionally, the surface of the buffer facing the first pipeline is provided with a groove, and the pressure sensor is embedded in the groove; the surface of the pressure sensor is covered with a protective thin plate.

[0012] Optionally, the protective sheet is a titanium alloy sheet with a thickness of 0.2 mm to 1 mm.

[0013] Optionally, the pebble bed type high-temperature gas-cooled reactor fuel element counting device further includes a signal processor and a DCS system, wherein the pressure sensor is connected to the signal processor; the signal processor and the first counting unit are respectively connected to the DCS system.

[0014] Optionally, the buffer includes a guide post, a first magnetic damping element, a second magnetic damping element, and a support element;

[0015] The guide post is arranged vertically, and the bottom of the guide post is fixed to the inner surface of the flow guide pipe; the first magnetic damping element is sleeved and fixed to the bottom end of the guide post, and the second magnetic damping element is movably sleeved on the top end of the guide post. The guide post is used to limit the movement of the second magnetic damping element relative to the first magnetic damping element; a repulsive force is formed between the second magnetic damping element and the first magnetic damping element.

[0016] The support member is fixed to the side of the second magnetic damping member away from the first magnetic damping member; the top of the support member is provided with a guide protrusion, and the inner surface of the flow guide pipe is provided with guide grooves distributed in the vertical direction. The guide protrusion is embedded in the guide grooves and can move in the vertical direction; the surface of the support member away from the second magnetic damping member forms an inclined surface that contacts the spherical element, and the pressure sensor is located below the inclined surface.

[0017] The spherical element falls onto the inclined surface under the action of gravity. The support is limited to move downward by the guide groove and the guide post, and the repulsive force between the second magnetic damping element and the first magnetic damping element buffers the kinetic energy of the support moving downward.

[0018] Optionally, the inner surface of the flow guide pipe has a first surface; the bottom of the support member has a second surface;

[0019] A portion of the second surface is fitted over the outside of the first surface; when the support moves downward, the first surface limits the movement of the support.

[0020] Optionally, the inclined surface of the support member and a portion of the inner surface of the guide pipe form a guide channel.

[0021] Optionally, the first counting unit is an eddy current counter.

[0022] According to a second aspect of the embodiments of this application, a method for counting fuel elements in a pebble bed type high-temperature gas-cooled reactor is provided, employing the pebble bed type high-temperature gas-cooled reactor fuel element counting device as described in the first aspect, comprising the following steps:

[0023] When the spherical element passes through the first pipe, the first counting unit performs the first count of the spherical element passing through the first pipe;

[0024] When the spherical element passing through the first pipe falls onto the buffer, the buffer cushions the kinetic energy of the spherical element, and the pressure sensor measures the pressure exerted by the spherical element on the buffer. Based on the measured value, a second count is performed on the spherical element passing through the guide pipe.

[0025] The results of the first and second counts are compared to verify the number of balls passing through the ball flow pipeline.

[0026] Optionally, a pressure sensor can be used to calculate the weight of the broken spherical element and the weight of the fragments.

[0027] One technical advantage of this invention is that:

[0028] In this embodiment, after the spherical element passes through the first pipeline and falls onto the buffer under gravity, a pressure sensor measures the pressure exerted by the spherical element on the buffer. Based on the measured value, a second count is performed on the spherical elements passing through the guide pipe. That is, the second counting unit realizes the counting measurement of the spherical elements through the pressure sensor. The pressure sensor is a contact measurement method, which is not easily affected by external environmental interference. Moreover, the pressure measurement can measure a large range of spherical element states, and the measurement results are less constrained by the detection limits of the spherical element's speed, size, etc. The measurement is very convenient and the measurement results are relatively accurate, while also ensuring the stable operation of the fuel loading and unloading system. Furthermore, by comparing the results of the first count with the results of the second count, the number of balls passing through the ball flow pipeline is checked, which significantly improves the accuracy of counting the spherical elements.

[0029] In addition, by processing and analyzing the pressure signals from the pressure sensor, the weight of the broken spherical element or fragments can be estimated. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the structure of a pebble bed type high-temperature gas-cooled reactor fuel element counting device according to an embodiment of the present invention;

[0031] Figure 2 This is a schematic diagram of the installation position of a pebble bed type high-temperature gas-cooled reactor fuel element counting device according to an embodiment of the present invention.

[0032] In the diagram: 100, counting device; 1, ball flow pipeline; 11, first pipeline; 12, guide pipeline; 121, guide groove; 122, first surface; 13, second pipeline; 2, first counting unit; 3, spherical element; 41, guide post; 42, first magnetic damping element;

[0033] 43. Second magnetic damping component; 44. Support component; 441. Guide protrusion; 442. Inclined surface;

[0034] 443. Second surface; 5. Pressure sensor; 6. Signal processor; 7. DCS system. Detailed Implementation

[0035] Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the present application.

[0036] The embodiments of this application will now be described in detail. Examples of these embodiments are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0037] The terms "first" and "second" in the specification and claims of this application may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise stated, "multiple" means two or more. Furthermore, "and / or" in the specification and claims indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0038] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and 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, and therefore should not be construed as a limitation of this application.

[0039] In the description of this application, it should be noted that, unless otherwise expressly 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 between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0040] like Figure 1 As shown, according to a first aspect of the embodiments of this application, a pebble bed type high-temperature gas-cooled reactor fuel element counting device is provided, including a pebble flow pipeline 1, a second pipeline 13, a first counting unit 2, and a second counting unit.

[0041] Specifically, the ball flow conduit 1 includes a first conduit 11, a guide conduit 12, and a second conduit 13 connected in sequence. The spherical element 3 can pass through the first conduit 11, the guide conduit 12, and the second conduit 13 in sequence. The first counting unit 2 is disposed in the first conduit 11 and is used to perform the first count of the spherical element 3 passing through the first conduit 11. For example, the material forming the structure of the guide conduit 12 is titanium alloy, and the guide conduit 12 can effectively restrict and guide the flow direction of the spherical element 3.

[0042] For example, the spherical element 3 can be a fuel element or a graphite sphere.

[0043] More specifically, the second counting unit includes a buffer and a pressure sensor 5. The buffer is movably disposed on the inner surface of the flow guide pipe 12, and the pressure sensor 5 is disposed on the buffer. When the spherical element 3 passing through the first pipe 11 falls on the buffer, the pressure sensor 5 measures the pressure exerted by the spherical element 3 on the buffer, and performs a second count on the spherical element 3 passing through the flow guide pipe 12 based on the measured value.

[0044] It should be noted that the pressure sensor 5 has properties such as high temperature resistance (approximately 350°C) and radiation resistance. For example, pressure sensors from the Honeywell 13 or 31 series can be selected.

[0045] The HTR-PM fuel loading and unloading system's ball flow pipeline 1 is divided into a descending section and an ascending section. In the descending section, the spherical element 3 moves downwards under its own weight. When it falls onto the buffer, it generates a strong force. Therefore, this force is used to detect whether any fuel elements or other spherical elements 3 have passed through, thus achieving ball counting. Some descending sections are long with significant height differences. To prevent damage or wear to the spherical element 3 when it collides with the buffer and to avoid affecting the reliability of the fuel loading and unloading system, the buffer effectively buffers the kinetic energy of the spherical element 3, thereby better protecting the spherical element 3 and preventing damage during collisions.

[0046] The results of the first count are compared with those of the second count to verify the number of balls passing through ball flow line 1.

[0047] In this embodiment, after the spherical element 3 passes through the first pipe 11 and falls onto the buffer under the action of gravity, the pressure sensor 5 measures the pressure exerted by the spherical element 3 on the buffer. Based on the measured value, a second count is performed on the spherical element 3 passing through the guide pipe 12. That is, the second counting unit realizes the counting measurement of the spherical element 3 through the pressure sensor 5. The pressure sensor 5 is a contact measurement method, which is not easily affected by the external environment. Moreover, the pressure measurement can measure a large range of states of the spherical element 3. The measurement result is less constrained by the detection limits such as the speed and size of the spherical element 3. The measurement is very convenient and the measurement result is relatively accurate. At the same time, it can also ensure the stable operation of the fuel loading and unloading system. Furthermore, by comparing the result of the first count with the result of the second count, the number of balls passing through the ball flow pipe 1 is checked, which significantly improves the accuracy of counting the spherical element 3.

[0048] In addition, by processing and analyzing the pressure signal from the pressure sensor 5, the weight of the broken spherical element 3 or fragments can be estimated.

[0049] Optionally, the surface of the buffer facing the first pipeline 11 is provided with a groove, and the pressure sensor 5 is embedded in the groove; the surface of the pressure sensor 5 is covered with a protective thin plate.

[0050] In the above embodiment, it is helpful to quickly and stably install the pressure sensor 5 on the buffer, thereby achieving accurate measurement of the pressure of the spherical element 3 falling on the buffer. The protective plate can effectively protect the pressure sensor 5.

[0051] Optionally, the protective plate is a titanium alloy plate of 0.2mm to 1mm. This allows the protective plate to both effectively protect the pressure sensor 5 and prevent it from affecting the pressure sensor 5.

[0052] For example, the protective plate is fixed to the buffer and has a certain degree of elasticity.

[0053] Optionally, the pebble bed type high-temperature gas-cooled reactor fuel element counting device further includes a signal processor 6 and a DCS system 7, wherein the pressure sensor 5 is connected to the signal processor 6; the signal processor 6 and the first counting unit 2 are respectively connected to the DCS system 7.

[0054] In the above embodiment, the signal processor 6 is connected to the pressure sensor 5 and performs signal processing functions such as detection, filtering, refining, amplification, and output. The signal processor 6 is connected to the DCS system 7 (reactor distributed control system), which automatically compares the measurement results of the pressure sensor 5 with the counting results of the first counting unit 2, and provides verification suggestions for the counting device 100, which helps to ensure the accuracy of the measurement results of the fuel element counting device of the pebble bed type high-temperature gas-cooled reactor.

[0055] Therefore, the measurement results of pressure sensor 5 are processed by signal processor 6 and transmitted to DCS system 7, and compared with the counting results of first counting unit 2 in real time. This allows for timely detection of counting measurement errors in first counting unit 2, ensuring the accuracy of the counting results.

[0056] In one specific implementation, the pressure sensor 5 is connected to the signal processor 6 via a cable. The signal processor 6 supplies power to the pressure sensor 5 and performs signal processing functions such as detection, filtering, refining, amplification, and output. Through testing, the pressure signal when a normal spherical element 3 passes through at various positions, as well as the reference pressure signal when spherical elements 3 of different sizes (masses) pass through, can be measured.

[0057] For example, the pressure sensor 5 transmits the measured signal to the DCS system 7, and the signal is analyzed and processed by a specific algorithm, including removing redundant signals generated by multiple bounces of a spherical element 3, filtering false signals caused by airflow disturbances or impacts from fine dust and debris, determining whether the spherical element 3 is damaged and estimating its size (mass), etc.

[0058] When the pressure sensor 5 records the passage of a spherical element 3, it compares the count with that of the upstream first counting unit 2. If there is a deviation, the DCS system 7 will automatically remind the user and provide a verification suggestion.

[0059] Optionally, the buffer includes a guide post 41, a first magnetic damping element 42, a second magnetic damping element 43, and a support element 44;

[0060] The guide post 41 is arranged vertically, and the bottom of the guide post 41 is fixed to the inner surface of the flow guide pipe 12; the first magnetic damping member 42 is sleeved and fixed to the bottom end of the guide post 41, and the second magnetic damping member 43 is movably sleeved on the top end of the guide post 41. The guide post 41 is used to limit the movement of the second magnetic damping member 43 relative to the first magnetic damping member; a repulsive force is formed between the second magnetic damping member 43 and the first magnetic damping member 42.

[0061] The support member 44 is fixed to the side of the second magnetic damping member 43 away from the first magnetic damping member 42; the top of the support member 44 is provided with a guide protrusion 441, and the inner surface of the flow guide pipe 12 is provided with guide grooves 121 distributed in the vertical direction. The guide protrusion 441 is embedded in the guide grooves 121 and can move in the vertical direction; the surface of the support member 44 away from the second magnetic damping member 43 forms an inclined surface 442 that contacts the spherical element 3, and the pressure sensor 5 is located below the inclined surface 442.

[0062] Under the influence of gravity, the spherical element 3 falls onto the inclined surface 442. The support member 44 is limited to move downward by the guide groove 121 and the guide post 41, and the repulsive force between the second magnetic damping member 43 and the first magnetic damping member 42 buffers the kinetic energy of the support member 44 moving downward.

[0063] In the above embodiment, the repulsive force between the first magnetic damping element 42 and the second magnetic damping element 43 is used to buffer the spherical element 3 during the collision process, and the buffering effect is good. For example, the magnetic poles of the first magnetic damping element 42 and the second magnetic damping element 43 are made of rare earth permanent magnet materials, and the matrix of the second magnetic damping element 43 is made of titanium alloy with high hardness, high strength and good plasticity, thereby ensuring the structural stability of the first magnetic damping element 42 and the second magnetic damping element 43, so that it can play a good buffering role on the support member 44.

[0064] For example, the support member 44 is provided with a clearance hole at the position corresponding to the guide post 41. The clearance hole provides clearance space for the guide post 41 when the support member 44 moves vertically downward, so as to avoid interference between the support member 44 and the guide post 41.

[0065] Optionally, the inner surface of the flow guide 12 has a first surface 122; the bottom of the support 44 has a second surface 443;

[0066] Part of the second surface 443 is fitted onto the outside of the first surface 122; when the support 44 moves downward, the first surface 122 limits the support 44.

[0067] In the above embodiment, the first surface 122 can limit the support member 44 when it moves vertically downward, ensuring the fixity and accuracy of the movement trajectory of the support member 44, thereby allowing the repulsive force between the first magnetic damping member 42 and the second magnetic damping member 43 to play a better buffering role.

[0068] Optionally, the inclined surface 442 of the support member 44 and a portion of the inner surface of the guide pipe 12 form a guide channel. This fully utilizes the structure of the buffer, allowing the spherical element 3 to pass smoothly through the guide channel, thereby optimizing the structure of the counting device 100.

[0069] Optionally, the first counting unit 2 is an eddy current counter. Eddy current counters perform non-contact continuous measurements, have high sensitivity and strong adaptability, and are thus able to perform stable measurements on the spherical element 3 passing through the first pipe 11.

[0070] In one specific implementation, a suitable type of pressure sensor 5 is selected through parameter analysis and experimental verification. The pressure sensor 5 can be Honeywell 13, 31 series, etc. In addition to meeting sufficiently high measurement accuracy, the performance requirements of the pressure sensor 5 must also meet the requirements of radiation resistance, high temperature resistance, and interference resistance. Furthermore, the size and structure of the pressure sensor 5 should be easy to install inside the buffer.

[0071] According to a second aspect of the embodiments of this application, a method for counting fuel elements in a pebble bed type high-temperature gas-cooled reactor is provided, employing the pebble bed type high-temperature gas-cooled reactor fuel element counting device as described in the first aspect, comprising the following steps:

[0072] When the spherical element 3 passes through the first pipe 11, the first counting unit 2 performs the first count on the spherical element 3 passing through the first pipe 11;

[0073] When the spherical element 3 passing through the first conduit 11 falls onto the buffer, the buffer cushions the kinetic energy of the spherical element 3, and the pressure sensor 5 measures the pressure exerted by the pressure sensor 5 on the spherical element 3 on the buffer, and performs a second count on the spherical element 3 passing through the guide conduit 12 based on the measured value.

[0074] The results of the first count are compared with those of the second count to verify the number of balls passing through ball flow line 1.

[0075] In the above embodiment, a contact measurement method is used to measure the number of spherical elements 3 passing through the flow guide pipe 12. The measurement results are not easily affected by the external environment, and the pressure measurement can measure a large range of states of the spherical elements 3. The measurement results are less constrained by the detection limits of the speed, size, etc. of the spherical elements 3, making the measurement very convenient and accurate, while also ensuring the stable operation of the fuel loading and unloading system. Furthermore, by comparing the results of the first count with the results of the second count to verify the number of balls passing through the ball flow pipe 1, the accuracy of counting the spherical elements 3 is significantly improved.

[0076] Optionally, pressure sensor 5 is used to calculate the weight of the broken spherical element 3 and the weight of the fragments. This enables rapid mass measurement of the broken spherical element 3 and the fragments.

[0077] In one specific implementation, see Figure 2 New fuel elements are loaded into a new fuel element storage device. A counting device 100 is installed on the descending section of the pipeline between the new fuel element storage device and the reactor core to measure the number of spherical elements 3 loaded into the reactor core. The spherical elements 3 in the reactor core pass through a fragmentation separator and enter a burnup measurement device, where the fragmentation separator separates the fragments and transports them to a fragmentation tank. A counting device 100 is installed on the descending section of the pipeline between the fragmentation separator and the fragmentation tank to measure the weight of the fragments. After being measured by the burnup measurement device, spherical elements 3 that meet the requirements are recycled back into the reactor core, while those that do not meet the requirements enter the spent fuel unloading storage device, then the spent fuel loading device, and finally the spent fuel tank. The use of a counting device 100 on the descending section of the pipeline between the burnup measurement device and the reactor core ensures accurate calculation of the number of spherical elements 3. Therefore, adding a counting device 100 at a critical location improves the accuracy of counting at each location and stage.

[0078] It should be noted that, given the importance of the spherical element 3 in the spherical flow path 1 for spherical counting, the accuracy of the measurement results from the counting device 100 must be guaranteed. However, currently applied and researched spherical counters are all based on non-contact measurement, and their measurement accuracy is easily affected by external interference. The pebble bed type high-temperature gas-cooled reactor fuel element counting device and method based on contact measurement provided in this application can significantly improve the accuracy of the quantity measurement of spherical elements 3, such as fuel elements. Furthermore, by comparing the results of the first and second counts to verify the number of spherical elements in the spherical flow path 1, common-mode failures that may occur with only one counting device 100 are avoided, further ensuring the accuracy of the measurement results for spherical elements in the spherical flow path 1.

[0079] It is understood that the above embodiments are merely exemplary implementations used to illustrate the principles of the present invention, and the present invention is not limited thereto. For those skilled 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 considered to be within the scope of protection of the present invention.

Claims

1. A pebble bed type high-temperature gas-cooled reactor fuel element counting device, characterized in that, include: A ball flow pipeline, comprising a first pipeline, a guide pipeline, and a second pipeline connected in sequence, wherein a spherical element can pass through the first pipeline, the guide pipeline, and the second pipeline in sequence; A first counting unit is disposed in the first pipeline and is used to perform a first count on the spherical element passing through the first pipeline; The second counting unit includes a buffer and a pressure sensor. The buffer is movably disposed on the inner surface of the flow guide pipe, and the pressure sensor is disposed on the buffer. When the spherical element passing through the first pipe falls on the buffer, the pressure sensor measures the pressure exerted by the spherical element on the buffer, and performs a second count on the spherical element passing through the flow guide pipe based on the measured value. The buffer includes a guide post, a first magnetic damping element, a second magnetic damping element, and a support element; The guide post is arranged vertically, and the bottom of the guide post is fixed to the inner surface of the flow guide pipe; the first magnetic damping element is sleeved and fixed to the bottom end of the guide post, and the second magnetic damping element is movably sleeved on the top end of the guide post. The guide post is used to limit the movement of the second magnetic damping element relative to the first magnetic damping element; a repulsive force is formed between the second magnetic damping element and the first magnetic damping element. The support member is fixed to the side of the second magnetic damping member away from the first magnetic damping member; the top of the support member is provided with a guide protrusion, and the inner surface of the flow guide pipe is provided with guide grooves distributed in the vertical direction. The guide protrusion is embedded in the guide grooves and can move in the vertical direction; the surface of the support member away from the second magnetic damping member forms an inclined surface that contacts the spherical element, and the pressure sensor is located below the inclined surface. The spherical element falls onto the inclined surface under the action of gravity. The support is limited to move downward by the guide groove and the guide post, and the repulsive force between the second magnetic damping element and the first magnetic damping element buffers the kinetic energy of the support moving downward. The results of the first and second counts are compared to verify the number of balls passing through the ball flow pipeline.

2. The pebble bed type high-temperature gas-cooled reactor fuel element counting device according to claim 1, characterized in that, The surface of the buffer facing the first pipeline is provided with a groove, and the pressure sensor is embedded in the groove; the surface of the pressure sensor is covered with a protective thin plate.

3. The pebble bed type high-temperature gas-cooled reactor fuel element counting device according to claim 2, characterized in that, The protective sheet is a titanium alloy plate with a thickness of 0.2mm to 1mm.

4. The pebble bed type high-temperature gas-cooled reactor fuel element counting device according to claim 3, characterized in that, It also includes a signal processor and a DCS system, with the pressure sensor connected to the signal processor; the signal processor and the first counting unit are respectively connected to the DCS system.

5. The pebble bed type high-temperature gas-cooled reactor fuel element counting device according to claim 4, characterized in that, The inner surface of the flow guide pipe has a first surface; the bottom of the support member has a second surface; A portion of the second surface is fitted over the outside of the first surface; when the support moves downward, the first surface limits the movement of the support.

6. The pebble bed type high-temperature gas-cooled reactor fuel element counting device according to claim 5, characterized in that, The inclined surface of the support member and part of the inner surface of the guide pipe form a guide channel.

7. The pebble bed type high-temperature gas-cooled reactor fuel element counting device according to claim 6, characterized in that, The first counting unit is an eddy current counter.

8. A method for counting fuel elements in a pebble bed type high-temperature gas-cooled reactor, characterized in that, The pebble bed type high-temperature gas-cooled reactor fuel element counting device as described in any one of claims 1 to 7 includes the following steps: When the spherical element passes through the first pipe, the first counting unit performs the first count of the spherical element passing through the first pipe; When the spherical element passing through the first conduit falls onto the buffer, the buffer cushions the kinetic energy of the spherical element, and the pressure sensor measures the pressure exerted by the spherical element on the buffer. Based on the measured value, a second count is performed on the spherical element passing through the guide conduit. The results of the first and second counts are compared to verify the number of balls passing through the ball flow pipeline.

9. The method for counting fuel elements in a pebble bed type high-temperature gas-cooled reactor according to claim 8, characterized in that, Pressure sensors are used to calculate the weight of the broken spherical component and the weight of the fragments.

Images