Spent fuel storage module aging monitoring system

Abstract

The present disclosure belongs to the technical field of nuclear power and specifically relates to a spent fuel storage module aging monitoring system. The outer wall of the plug body cooperates with the inner wall of the inserted monitoring through hole, and the first step portion of the test block plug is pressed against the second step portion of the inserted monitoring through hole, so that effective plugging of the monitoring through hole can be formed, multi-angle interception of the rays escaping from the gap is formed through the inclined surface of the plug body at different inclination angles, and the shielding effect is enhanced. The integrated structure of the hanger and the plug body simplifies the operation of putting in / taking out the test block and shielding radiation into a single operation of inserting and pulling out the test block plug, improves the operation efficiency of putting in and taking out the test block, and reduces the radiation dose of personnel. In addition, the present disclosure can flexibly select different types of test blocks to be put into the storage module according to the needs of aging monitoring, and provides a wide range of test application scenarios for the aging monitoring of the storage module.

Description

Technical Field

[0001] This invention belongs to the field of nuclear power technology, specifically relating to an aging monitoring system for spent fuel storage modules. Background Technology

[0002] In related technologies, containers for dry storage of spent heavy water reactor fuel (such as dry storage tanks) need to be periodically tested for leaks using helium mass spectrometry or pressure decay to verify their sealing performance. Thermocouples, strain gauges, or fiber optic sensors pre-embedded around the storage container can also be used to continuously track the temperature, stress, and deformation of the container. All monitoring data is transmitted to a central control room, where professionals analyze and generate reports. This allows for monitoring of material degradation caused by high temperatures and the potential for structural damage due to abnormal stress, ensuring the safety of the storage container. However, current technology only supports passive monitoring, and further improvements in risk control are urgently needed. Summary of the Invention

[0003] To overcome the problems existing in related technologies, an aging monitoring system for spent fuel storage modules is provided.

[0004] According to one aspect of the present disclosure, an aging monitoring system for a spent fuel storage module is provided. The system includes multiple test plugs, and a hollow structure of the storage module is used to store a spent fuel storage cylinder. The top plate of the storage module has multiple monitoring through holes along the axial direction, and a test plug is inserted into each monitoring through hole. A rainproof cover is fixedly installed on the opening of the monitoring through hole. Each test block plug includes a plug body and a bracket. The plug body comprises multiple segments connected end-to-end axially. The topmost segment is fixedly connected to a lifting ring for hoisting. Each segment is an inverted platform, and the tilt angles of different segments within each test block plug are different. Except for the bottommost segment, the lower end area of ​​each segment is larger than the upper end area of ​​the segment fixedly connected below, creating a circumferential first step at the connection between the lower end face of each segment and the adjacent segment below. The lower end of the bottommost segment is fixedly connected to the upper end of the bracket, and the edge of the bracket does not exceed the axial space formed by the edge of the lower end face of the bottommost segment. The bracket is used to place one or more test blocks requiring aging monitoring. Each monitoring through hole has a second step extending radially inward on its inner wall. The number and position of the second step in each monitoring through hole match the number and position of the first step in the plug. The first step of the test block plug inserted into the monitoring through hole presses against the second step at the corresponding position in the monitoring through hole. The outer wall of each test plug is fitted with the inner wall of the insertion monitoring through hole with a clearance fit, and the bracket of each test plug passes through the corresponding monitoring through hole and is exposed to the environment inside the storage module.

[0005] In one possible implementation, the test block comprises a concrete block cast concurrently with the storage module, or stainless steel and / or a coating of the same material as the storage cylinder.

[0006] In one possible implementation, the test blocks in the rack are of different types, partially the same, or all the same.

[0007] In one possible implementation, the horizontal gap between the outer wall of each test block plug and the inner wall of the inserted monitoring through hole is no more than 5 mm.

[0008] In one possible implementation, the plug body of the test block plug is an integrally cast concrete module, the plug body is wrapped with a stainless steel plate, the bracket is made of stainless steel, and the upper end of the bracket is fixedly connected to the lower end of the plug body by welding.

[0009] In one possible implementation, the bracket includes multiple angle steels and a base plate. One end of the multiple angle steels is welded around a stainless steel plate on the outside of the plug body, and the other end of the multiple angle steels is welded to the edge of the base plate. The multiple angle steels are evenly distributed around the axis of the plug body, and the test block is placed in the space enclosed by the multiple angle steels and the base plate from bottom to top.

[0010] In one possible implementation, the bracket includes a support rod and multiple test block boxes with openings at the top. The upper end of the support rod is embedded in the concrete structure of the test block plug. Each test block box is welded to the support rod from bottom to top. Each test block box is used to hold one or more test blocks. The side wall height of each test block box is greater than the height of the test block.

[0011] In one possible implementation, the support rod passes through the center of the bottom of each test block box and is welded to the center of the bottom of each test block box; or the support rod is welded to the side of each test block box.

[0012] In one possible implementation, the test block boxes are different in size and shape, partially the same, or completely the same.

[0013] In one possible implementation, the inner wall of each monitoring through hole is covered with a stainless steel plate, and multiple reinforcing ribs are arranged circumferentially on the outer side of the stainless steel plate. The multiple reinforcing ribs are pre-embedded in the top plate of the storage module.

[0014] In one possible implementation, a dam is formed circumferentially at the opening of each monitoring through hole, with a pre-set height on the upper surface of the top plate. A sealing ring is set on the top of the dam, and a rain cover is placed on the sealing ring, covering the dam inside the rain cover. An asbestos pad is laid around the connection between the top surface of the storage module and the cofferdam. The edges of the rain cover are set on the asbestos pad and welded around the outer wall of the cofferdam at the location on the top plate.

[0015] In one possible implementation, the storage module has a ventilation structure, with each monitoring through-hole opened on the top plate near the ventilation structure and the storage cylinder, such that the hanger of the test block plug inserted into the monitoring through-hole is exposed in the air outlet channel of the storage module.

[0016] The beneficial effects of this disclosure are as follows: the outer wall of the plug body fits the inner wall of the inserted monitoring through-hole with a clearance, and the first step of the plug presses against the second step of the inserted monitoring through-hole, thereby effectively sealing the monitoring through-hole. The inclined surfaces of the plug body at different angles intercept rays escaping through the gaps at multiple angles, enhancing the shielding effect. The integrated structure of the bracket and the plug body simplifies the operation of inserting / removing the test block and shielding radiation to a single operation of inserting and removing the test block plug, improving the efficiency of inserting and removing the test block and reducing personnel radiation dose. Furthermore, this disclosure allows for the flexible selection of different types of test blocks to be placed in the storage module according to the needs of aging monitoring, providing a wide range of experimental application scenarios for aging monitoring of the storage module. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of a test block plug shown in an embodiment of this disclosure.

[0018] Figure 2 This is a schematic diagram of an aging monitoring system for a spent fuel storage module, as shown in an embodiment of this disclosure.

[0019] In the picture: 1. Plug; 2. Hanging frame; 3. Top plate; 4. Rain cover; 5. Cofferdam; 6. Asbestos mat; 7. Reinforcing ribs; 11. Segmentation; 111. First step section; 31. Monitoring through hole; 32. Air outlet; 311. The second step; Detailed Implementation

[0020] The present disclosure will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0021] Unless otherwise defined, the technical and scientific terms used in this disclosure have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains; the terminology used in this disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of this disclosure; the term "comprising" and any variations thereof in this disclosure are intended to cover non-exclusive inclusion. Clearly, the embodiments described in this disclosure are only a part of the embodiments of this disclosure, and not all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of this disclosure without inventive effort are within the scope of protection of this disclosure.

[0022] In this disclosure, the reference to "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this disclosure. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0023] Figure 1 This is a schematic diagram of a test block plug according to an embodiment of this disclosure. Figure 2 This is a schematic diagram of an aging monitoring system for a spent fuel storage module, as shown in an embodiment of this disclosure. Figure 1 and Figure 2 As shown, the aging monitoring system of the spent fuel storage module includes multiple test plugs. The hollow structure of the storage module is used to store the spent fuel storage cylinder. The top plate 3 of the storage module has multiple monitoring through holes 31 along the axial direction. A test plug is inserted into each monitoring through hole 31. A rain cover 4 is fixedly covered on the opening of the monitoring through hole 31.

[0024] Each test block plug includes a plug body 1 and a hanger 2. In each test block plug, the plug body 1 has a symmetrical structure and includes multiple segments 11. Each segment 11 is connected end to end in the axial direction to form an approximately inverted cone shape. The top of the uppermost segment 11 is fixedly connected to a lifting ring for hoisting. Each segment 11 is an inverted platform. Except for the lowermost segment 11, the lower end area of ​​each segment 11 is larger than the upper end area of ​​the segment 11 fixedly connected below, so that the lower end face of each segment 11 and the connection point of the adjacent segment 11 below form a circumferential first step 111. The lower end of the lowermost segment 11 is fixedly connected to the upper end of the hanger 2. The edge of the hanger 2 does not exceed the space formed by the lower end face edge of the lowermost segment 11 in the axial direction. The hanger 2 is used to place one or more test blocks that need to be monitored for aging. The test blocks can be concrete blocks poured at the same time as the storage module, or they can be stainless steel and coatings of the same material as the storage cylinder. Monitoring personnel can select any type of test block to place in rack 2 according to the monitoring needs. The types of test blocks in rack 2 can be different, partially the same, or all the same.

[0025] The tilt angles of different segments 11 in each test block plug are different, resulting in each segment 11 having a side with a different tilt angle. The tilt angle of a platform-shaped segment 11 can be expressed as the angle between the platform's generatrix and its lower end face. For example, the tilt angles of each segment 11 can decrease sequentially from top to bottom, or increase sequentially, or vary irregularly. Figure 1As shown, the plug body 1 may include two segments 11. The tilt angle of the upper segment 11 may be between 71° and 80°, and the tilt angle of the lower segment 11 may be between 60° and 70°. The number of plug body segments and the tilt angle of the segments can be set as needed, and this disclosure does not limit them.

[0026] Each monitoring through-hole 31 has a second step portion 311 extending radially inward on its inner wall. The number and position of the second step portions 311 in each monitoring through-hole 31 match the number and position of the first step portions 111 in the plug body 1. The first step portion 111 of the test block plug inserted into the monitoring through-hole 31 presses against the corresponding second step portion 311 in the monitoring through-hole 31. The outer wall of the plug body 1 of each test block plug is clearance-fitted with the inner wall of the inserted monitoring through-hole 31, wherein the horizontal gap between the outer wall of the plug body 1 of each test block plug and the inner wall of the inserted monitoring through-hole 31 may not exceed 5 mm. The bracket 2 of each test block plug passes through the corresponding monitoring through-hole 31 and is exposed to the environment inside the storage module, so that the test block in the bracket 2 is in the same operating environment as the various components in the storage module.

[0027] The test block plug provided in this disclosure has an outer wall that fits with the inner wall of the inserted monitoring through-hole, and the first stepped portion of the test block plug presses against the second stepped portion of the inserted monitoring through-hole, thereby effectively sealing the monitoring through-hole and preventing radiation from escaping from the storage module. Because each segment of the test block plug has a slope with a different inclination angle, even if radiation escapes through the gap between the lower segment of the plug and the monitoring through-hole, it will still be intercepted and shielded by the slopes of the upper segment of the plug at different inclination angles. Thus, the slopes of the plug at different inclination angles form a multi-angle interception of radiation escaping through the gap, enhancing the shielding effect. The integrated structure of the bracket and the plug body simplifies the operation of inserting / removing the test block and shielding radiation to a single operation of inserting and removing the test block plug, improving the efficiency of inserting and removing the test block and reducing the radiation dose to personnel.

[0028] Furthermore, this disclosure allows for the flexible selection of different types of test blocks to be placed in the storage module according to the needs of aging monitoring. In other words, compared to sensor monitoring systems that can only monitor existing components and materials within the storage module, the aging monitoring of this disclosure is no longer limited to the existing resources of the storage module. Test blocks can be materials or components formed concurrently with the storage module, or materials or components that have not yet been put into actual operation. Thus, the system of this disclosure significantly expands the types and scope of aging monitoring objects while ensuring that the aging monitoring environment is consistent with the operating environment of the storage module, providing a wide range of experimental application scenarios for aging monitoring of the storage module.

[0029] In one possible implementation, the plug body 1 of the test block plug is an integrally cast concrete module. The lifting ring at the top of the plug body 1 can be pre-embedded in the plug body 1. The plug body 1 is wrapped with a stainless steel plate. The material of the bracket 2 is stainless steel. The upper end of the bracket 2 is fixedly connected to the lower end of the plug body 1 by pre-embedding.

[0030] In one possible implementation, the bracket includes a top cover, multiple angle steels, and a base plate. The connecting rod at the upper end of the top cover is embedded in the plug body. One end of the multiple angle steels is welded around the top cover, and the other end of the multiple angle steels is welded to the edge of the base plate. The multiple angle steels are evenly distributed around the axis of the plug body. The test block is placed in the space enclosed by the top cover, multiple angle steels, and base plate from bottom to top.

[0031] In one possible implementation, the rack includes a support rod and multiple open-top test block boxes. The upper end of the support rod is embedded in the concrete structure of the test block plug. Each test block box is welded to the support rod from bottom to top. Each test block box is used to hold one or more test blocks. The side wall height of each test block box is greater than the height of the test block. The support rod can pass through the center of the bottom of each test block box and be welded to the center of the bottom of each test block box. The support rod can also be welded to the side of each test block box. The size and shape of each test block box can be different, partially the same, or all the same. Since the aging monitoring cycle is usually greater than 10 years, the rack containing test block boxes of different shapes can hold test blocks of different sizes and shapes in the same batch, significantly improving monitoring efficiency. Because the test block boxes have an open-top structure and the side wall height of each test block box is greater than the height of the test block, it is convenient for monitoring personnel to put and take out test blocks, reducing personnel operation time and radiation dose, and it can also prevent test blocks from falling into the storage module, avoiding additional contamination.

[0032] In one possible implementation, such as Figure 1 As shown, the inner wall of each monitoring through hole 31 is covered with a stainless steel plate, and multiple reinforcing ribs 7 are arranged circumferentially on the outer side of the stainless steel plate. The multiple reinforcing ribs 7 are embedded in the top plate 3 of the storage module, thereby enhancing the stability of the monitoring through hole 31.

[0033] In one possible implementation, such as Figure 1 As shown, a dam 5, at a predetermined height above the upper surface of the top plate 3, is formed circumferentially at the opening of each monitoring through-hole 31. A sealing ring is installed on the top of the dam 5, and a rain cover 4 is placed on the sealing ring, enclosing the dam 5 inside the rain cover 4. An asbestos pad 6 is laid circumferentially at the connection between the upper surface of the storage module top plate 3 and the dam 5. The edges of the rain cover 4 are placed on the asbestos pad 6 and circumferentially welded to the outer wall of the dam 5 at the position on the top plate 3. In this way, the dam can prevent water accumulation on the top plate of the storage module from backflowing into the monitoring through-holes, the sealing ring can further prevent the leakage of internal radiation from the storage module, and the asbestos pad can prevent damage to the top plate of the storage module during the welding process of the edge of the rain cover.

[0034] In one possible implementation, such as Figure 1 and Figure 2 As shown, the storage module has a ventilation structure. Each monitoring through-hole 31 is located on the top plate 3 near the ventilation structure and the storage cylinder, and near the air outlet 32, so that the bracket 2 of the test block plug inserted into the monitoring through-hole 31 is exposed in the air outlet channel of the storage module. This allows the test block to have more full contact with the internal environment of the storage module, and has less impact on the integrity and stability of the structure of the top plate of the storage module.

[0035] The various embodiments of this disclosure have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or improvement of the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. An aging monitoring system for spent fuel storage modules, characterized in that, The system includes multiple test plugs, and the hollow structure of the storage module is used to store spent fuel storage cylinders; the top plate of the storage module has multiple monitoring through holes along the axial direction, and a test plug is inserted into each monitoring through hole, and a rainproof cover is fixedly installed on the opening of the monitoring through hole; Each test block plug includes a plug body and a bracket. The plug body comprises multiple segments connected end-to-end axially. The topmost segment is fixedly connected to a lifting ring for hoisting. Each segment is an inverted platform, and the tilt angles of different segments within each test block plug are different. Except for the bottommost segment, the lower end area of ​​each segment is larger than the upper end area of ​​the segment fixedly connected below, creating a circumferential first step at the connection between the lower end face of each segment and the adjacent segment below. The lower end of the bottommost segment is fixedly connected to the upper end of the bracket, and the edge of the bracket does not exceed the axial space formed by the edge of the lower end face of the bottommost segment. The bracket is used to place one or more test blocks requiring aging monitoring. Each monitoring through hole has a second step extending radially inward on its inner wall. The number and position of the second step in each monitoring through hole match the number and position of the first step in the plug. The first step of the test block plug inserted into the monitoring through hole presses against the second step at the corresponding position in the monitoring through hole. The outer wall of each test plug is fitted with the inner wall of the insertion monitoring through hole with a clearance fit, and the bracket of each test plug passes through the corresponding monitoring through hole and is exposed to the environment inside the storage module.

2. The system according to claim 1, characterized in that, Test blocks include concrete blocks poured concurrently with the storage modules, or stainless steel and / or coatings of the same material as the storage cylinder.

3. The system according to claim 1, characterized in that, The test blocks in the rack are of different types, partially the same, or all the same.

4. The system according to claim 1, characterized in that, The horizontal gap between the outer wall of each test block plug and the inner wall of the inserted monitoring through hole shall not exceed 5 mm.

5. The system according to claim 1, characterized in that, The plug body of the test block is an integrally cast concrete module, and the outside of the plug body is wrapped with a stainless steel plate. The bracket is made of stainless steel, and the upper end of the bracket is fixedly connected to the lower end of the plug body by pre-embedding.

6. The system according to claim 1, characterized in that, The bracket includes a top cover, multiple angle steels and a base plate. One end of the multiple angle steels is welded around the stainless steel plate on the outside of the plug body, and the other end of the multiple angle steels is welded to the edge of the base plate. The multiple angle steels are evenly distributed around the axis of the plug body. The test block is placed in the space enclosed by the multiple angle steels and the base plate from bottom to top.

7. The system according to claim 1, characterized in that, The bracket includes a support rod and multiple test block boxes with openings at the top. The upper end of the support rod is embedded in the concrete structure of the test block plug. Each test block box is welded to the support rod from bottom to top. Each test block box is used to hold one or more test blocks. The side wall height of each test block box is greater than the height of the test block.

8. The system according to claim 7, characterized in that, The support rod passes through the center of the bottom of each test block box and is welded to the center of the bottom of each test block box, or the support rod is welded to the side of each test block box.

9. The system according to claim 1, characterized in that, The size and shape of each test block box are different from each other, partially the same or completely the same.

10. The system according to claim 1, characterized in that, The inner wall of each monitoring through hole is covered with a stainless steel plate, and multiple reinforcing ribs are arranged circumferentially on the outer side of the stainless steel plate. These reinforcing ribs are pre-embedded in the top plate of the storage module.

11. The system according to claim 1, characterized in that, At the opening of each monitoring through hole, a circumferential dam is formed at a preset height on the upper surface of the top plate. A sealing ring is installed at the top of the dam, and a rain cover is placed on the sealing ring, covering the dam inside the rain cover. An asbestos pad is laid around the connection between the top surface of the storage module and the cofferdam. The edges of the rain cover are set on the asbestos pad and welded around the outer wall of the cofferdam at the location on the top plate.

12. The system according to claim 1, characterized in that, The storage module has a ventilation structure, with each monitoring through hole located on the top plate near the ventilation structure and the storage cylinder, so that the bracket of the test block plug inserted into the monitoring through hole is exposed in the air outlet channel of the storage module.

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