Irradiation sample well plug

Abstract

The application provides an irradiation sample hole plug, which comprises an upper cylinder, a pin, an outer spring, an inner spring, a core rod, a connecting rod, a plug body and a stopper. The stopper is fixed on the plug body through the pin and is configured to rotate around the pin shaft. The upper cylinder is installed on the plug body through two pins. The outer spring is installed between the upper cylinder and the plug body, and the upper cylinder moves up and down through the pin holes on both sides of the plug body to compress the outer spring. The inner spring is arranged at the gap between the core rod and the plug body. The core rod is connected with the connecting rod through the pin, the connecting rod is connected with the stopper through the pin, and the stopper is fixed with the plug body through the pin. The driving mode of the stopper is to rely on the core rod and the connecting rod. The application improves the structure of the hole plug, adopts mechanical self-locking, optimizes the structure under the premise of not changing the original design, adopts the connecting rod type structure, and increases the anti-impact function, so as to solve the problem of how to reduce the impact of the irradiation sample hole plug in the prior art.

Description

Technical Field

[0001] This application belongs to the field of nuclear power technology, specifically relating to an irradiated sample well plug. Background Technology

[0002] An irradiation sample holder is installed on the basket of the pressurized water reactor internals. The sample material placed in the irradiation sample holder is exactly the same as the material of the reactor pressure vessel, so that it can be removed for mechanical property testing at different stages of the reactor's life. Correspondingly, holes are made on the basket flange at the positions of the irradiation sample holder to allow for the removal of the irradiated sample using a special long-handled tool. To prevent additional bypass flow, irradiation sample plugs are placed at the opening positions to limit bypass flow during reactor operation.

[0003] In pressurized water reactor types such as CNP600, CNP1000, and Hualong One, irradiation sample well plugs are installed on the basket flanges of the lower in-reactor components. Currently, reference Figure 1 and Figure 2 The irradiation sample well plug for a pressurized water reactor (PWR) consists of an upper end 1, an optical shaft 2, a base 3, and a spring 4. The well plug has a radial clearance fit with the basket flange hole, but no axial restraint. The upper end is the upper internal reactor component. During refueling overhauls, after disassembling and tightening the upper internal reactor component holding the irradiation sample well plug in place, there are no restraining components above the plug. During reactor safety injection tests or when water is added to the reactor (i.e., water is flushed from below the plug), the plug is easily dislodged. Therefore, there is a possibility that the irradiation sample well plug could be dislodged by the primary coolant and randomly scattered throughout the reactor, posing a significant safety hazard.

[0004] The current pressurized water reactor nuclear power units all use this structure for the irradiation sample plugs, including reactor types such as CNP600, CNP1000, and Hualong One, and improvements are urgently needed.

[0005] For example, Patent 1 (application number 201910994798.9) discloses a wedge-groove self-locking irradiation sample hole plug and its implementation method. However, this irradiation sample hole plug is not suitable for use in pressurized water reactor nuclear power units because the wedge-groove self-locking irradiation sample hole plug relies on the impact pressure of water flow to generate self-locking, which is unreliable. The two ends of the irradiation sample hole plug protrude, which does not meet the requirements of the basket structure of the nuclear power unit. When installed on the conical basket, the bottom of the basket flange is not flat, making the wedge-groove self-locking irradiation sample hole plug unsuitable for use in current nuclear power units. Furthermore, the upper end of the wedge-groove self-locking irradiation sample hole plug lacks springs or other elastic components, making it unsuitable for in-reactor use. Therefore, it is not used in the nuclear power industry.

[0006] Patent 2 (application number 201310311304.5) discloses a ball-bearing conical irradiation sample well plug with a self-locking function for pressurized water reactors. However, this ball-bearing conical irradiation sample well plug is also unsuitable for use in pressurized water reactor nuclear power units. The reason is that this plug relies on the axial force generated by water flow impact, which is converted into horizontal tension through a wedge-shaped surface, generating friction between the plug and the well wall to prevent it from being ejected. This design principle is unreliable, and the risk of ejection remains. Furthermore, due to the unverifiable reliability of the technology relying on water flow impact to generate circumferential friction, it has not been applied in engineering and is not used in the nuclear power industry.

[0007] Patent 3 (application number 201910567106.2) discloses a limiting irradiation sample hole plug and a locking method. This limiting irradiation sample hole plug is also unsuitable for use in pressurized water reactor nuclear power units because the bottom of the basket is a conical surface, not a flat surface, making it unsuitable for pressurized water reactor nuclear power units; the upper end of this limiting irradiation sample hole plug lacks springs or other elastic components, making it unsuitable for in-reactor use; and the structure of this limiting irradiation sample hole plug is complex, making its use in reactors unreliable, and therefore it has not been used in the nuclear power industry.

[0008] Therefore, how to reduce the problem of the pore plug of the irradiated sample being easily blown out has become an urgent technical problem to be solved. Summary of the Invention

[0009] In view of this, the embodiments of this application are committed to providing an irradiation sample well plug. By improving the well plug structure and adopting mechanical self-locking, the structure is optimized without changing the original design. A linkage structure is adopted to increase the anti-blowout function, so as to solve the problem of how to reduce the easy blowout of the irradiation sample well plug in the prior art, which has become an urgent technical problem to be solved.

[0010] This application provides an irradiation sample well plug, which includes an upper cylinder, a pin, an outer spring, an inner spring, a core rod, a connecting rod, a plug body, and a stop block. The stop block is fixed to the plug body by the pin and is configured to rotate around the pin axis. The upper cylinder is mounted on the plug body by two pins. An outer spring is installed between the upper cylinder and the plug body, and the upper cylinder compresses the outer spring by moving up and down in the pin holes on both sides of the plug body. The inner spring is disposed in the gap between the core rod and the plug body. The core rod and the connecting rod are connected by a pin, the connecting rod and the stop block are connected by a pin, and the stop block is fixed to the plug body by a pin. The stop block is driven by the core rod and the connecting rod. When the core rod is in the upper position, the connecting rod drives the stop block to rotate clockwise around the pin axis and retract into the plug body; when the core rod is in the lower position, the connecting rod drives the stop block to rotate counterclockwise around the pin axis, and the stop block extends out of the outer surface of the plug body, interfering axially with the flange surface of the upper component to achieve self-locking.

[0011] In one specific embodiment of this application, the thickness of the irradiated sample hole plug is greater than the thickness of the basket flange.

[0012] In one specific embodiment of this application, the lower end of the plug is cone-shaped.

[0013] In one specific embodiment of this application, the irradiated sample well plug further includes a gripping operation sleeve. The gripping operation sleeve is threadedly connected to the core rod and installed at the center of the plug body to serve as a drive stop.

[0014] In one specific embodiment of this application, the gripping operation sleeve is cylindrical with multiple gaps evenly arranged in the circumferential direction.

[0015] In one specific embodiment of this application, the irradiation sample well plug also includes an end cap. The end cap is fixed to the plug body by threads.

[0016] The beneficial effects of the technical solution of this application are as follows: without changing the original design function of the irradiated sample plug, it adapts to the existing basket structure and installation interface, improves the plug structure, adds anti-explosion function, and adopts an active locking mechanical structure and a linkage structure to achieve the anti-explosion function. Attached Figure Description

[0017] Figure 1 The diagram shows a schematic of the structure of an irradiated sample plug for a pressurized water reactor.

[0018] Figure 2 As shown Figure 1 The diagram shows the usage status of the irradiated sample well plug for pressurized water reactors.

[0019] Figure 3 The diagram shown is a structural schematic of an irradiated sample pore plug provided in an embodiment of this application.

[0020] Figure 4 As shown Figure 3 The diagram shows a cross-sectional view of the irradiated sample with the stopper protruding from the irradiated sample hole plug.

[0021] Figure 5 As shown Figure 3 The diagram shows a cross-sectional view of the irradiated sample hole plug as the stopper retracts.

[0022] Figure 6 The image shown is an external view of an irradiated sample pore plug provided in an embodiment of this application.

[0023] Figure 7 As shown Figure 3 The irradiated sample plug and Figure 1 The diagram shows a comparison of the installation of the irradiated sample plug for a pressurized water reactor.

[0024] Figure 8 As shown Figure 3 The diagram shows the installation of the stopper in the irradiated sample well plug when it is retracted.

[0025] Figure 9 As shown Figure 3 The diagram shows the installation of the stopper in the irradiated sample well plug when it is extended.

[0026] Figure 10 As shown Figure 3 The diagram shows the structural schematic of the connecting rod and slider mechanism in the irradiated sample hole plug. Detailed Implementation

[0027] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0028] At least one embodiment of this application provides an irradiation sample well plug, see reference. Figures 3 to 10 The irradiated sample well plug 11 includes an upper cylinder 1, a pin 2, an outer spring 3, an inner spring 4, a core rod 5, a connecting rod 6, a plug body 7, and a stop block 10. The stop block 10 is fixed to the plug body 7 by the pin 2 and is configured to rotate around the pin axis. The upper cylinder 1 is mounted on the plug body 7 by two pins 2. An outer spring 3 is installed between the upper cylinder 1 and the plug body 7, and the upper cylinder 1 compresses the outer spring 3 by moving up and down in the pin holes on both sides of the plug body 7. The inner spring 4 is located in the gap between the core rod 5 and the plug body 7. The core rod 5 is connected to the connecting rod 6 by the pin 2, the connecting rod 6 is connected to the stop block 10 by the pin 2, and the stop block 10 is fixed to the plug body 7 by the pin 2. The stop block 10 is driven by the core rod 5 and the connecting rod 6. When the core rod 5 is in the upper position, the connecting rod 6 drives the stop block 10 to rotate clockwise around the pin shaft and retract into the plug body 7; when the core rod 5 is in the lower position, the connecting rod 6 drives the stop block 10 to rotate counterclockwise around the pin shaft, the stop block 10 extends out of the outer surface of the plug body 7 and forms axial interference with the flange surface of the upper component to achieve self-locking.

[0029] It should be noted that the irradiated sample well plug 11 is a linkage-type anti-ejection structure well plug. The plug body 7 is the main structural component of the entire irradiated sample well plug 11, providing a structural framework for other components. The stop block 10 can rotate around a fixed pin. When the core rod 5 is lifted, the stop block 10 is driven to rotate via the connecting rod 6, causing the stop block 10 to retract into the plug body 7. Continuing to lift upwards, the irradiated sample well plug 11 can be removed.

[0030] According to the technical solution provided in the embodiments of this application, by setting the core rod 5, connecting rod 6, plug body 7 and stop block 10 components in the irradiated sample plug 11, in the natural state, the stop block 10 is flattened by the compression force of the inner spring 4 and the gravity of the core rod 5 through the connecting rod 6, and the stop block 10 protrudes from the outer cylinder surface of the plug body 7. The limit of the upper component flange prevents the plug from being pushed out. At the same time, after the stop block 10 is flattened, it cannot continue to rotate downward due to the spatial structure limitation. When the water flow impacts, the force direction is also downward, which has the safety of the structural design. At the same time, by using the dual action of the inner spring and gravity of the core rod 5, the stop block 10 is extended in the natural state and protrudes from the outer cylinder surface of the plug 11. Furthermore, by setting a stop 10 in the irradiated sample plug 11, and considering the limited space below the basket flange, only one stop is needed to accommodate the unique structural dimensions of the pressurized water reactor nuclear power unit's internal components. Since one side of the internal component flange is conical and the other side is flat, the stop can only act on the flat side. Therefore, only one stop is needed, resulting in a simple structure that meets the self-locking requirements. This allows for the use of a conical structure below the flange of the lower internal components of the nuclear power unit, avoiding interference with the conical surface and simultaneously preventing axial ejection. In addition, an external spring 3 is installed at the upper end of the irradiated sample plug 11, which provides axial constraint for the irradiated sample plug 11 after installation within the internal components.

[0031] This application embodiment adopts a special mechanical structure design to change the previous hole plug structure, so that it has the function of preventing water flow out, improving the reliability of unit operation and reducing the risk of component detachment.

[0032] In at least one embodiment of this application, the thickness of the irradiated sample plug 11 is greater than the thickness of the basket flange. Thus, referring to... Figure 7 The original plug 20 is relatively short and is installed in the mounting hole of the basket flange 30 without axial constraint between it and the flange hole. However, the irradiated sample plug 11 is relatively long. The upper end of the irradiated sample plug 11 can sit on the basket flange 30, and the lower end of the irradiated sample plug 11 can penetrate the entire thickness of the basket flange. The stop block 10 is opened and protrudes from the outer cylinder surface of the plug body 7, supporting it under the basket flange, further preventing water from being flushed out.

[0033] In its natural state, the upper cylinder 1 is lifted up. After the irradiated sample plug 11 is installed, the upper internal component 40 compresses the outer spring 3 downward through the upper cylinder 1, which plays a role in axial positioning of the plug and prevents the plug from moving up and down when impacted by water flow.

[0034] In at least one embodiment of this application, the lower end of the plug 7 is cone-shaped. Thus, by employing an internal external spring and an external cone-shaped lower end structure, the original structural characteristics and design functions of the plug are maintained. This allows the irradiation sample plug for nuclear power unit irradiation sample holders to be applicable to pressurized water reactor nuclear power units, facilitating installation. It provides both installation guidance and maintains axial elastic constraint after in-core installation, thus preserving its original design functions.

[0035] In at least one embodiment of this application, reference is made to Figure 4 and Figure 5 The irradiated sample well plug 11 also includes a gripping operation sleeve 8. The gripping operation sleeve 8 is threadedly connected to the core rod 5 and installed at the center of the plug body 7 to drive the stop block 10. Thus, in its natural state, the core rod 5 is in the lower position under the action of spring force; when the gripping operation sleeve 8 is lifted upward, the gripping operation sleeve 8 drives the core rod 5 to move upward. When the gripping operation sleeve 8 is lifted, the linkage slider mechanism of "gripping operation sleeve 8 - core rod 5 - connecting rod 6 - stop block 10" plays a driving chain transmission role, causing the stop block 10 to retract, without interfering with the flange surface of the upper component and forming a self-locking mechanism. The irradiated sample well plug 11 can be smoothly removed upward and separated from the internal components, that is, the effect of the stop block 10 retracting first and then the well plug 11 being removed is achieved.

[0036] In at least one embodiment of this application, the gripping operation sleeve 8 is cylindrical, with multiple gaps evenly arranged around its circumference. Thus, by utilizing these multiple gaps, a gripping tool can be used for gripping.

[0037] For example, multiple neutral positions can be 3 neutral positions.

[0038] In at least one embodiment of this application, reference is made to Figure 4 and Figure 5 The irradiated sample well plug 11 also includes an end cap 9. The end cap 9 is fixed to the plug body 7 by threads. In this way, the core rod 5 can move up and down within a certain range at the center of the plug body 7 by the limiting action of the end cap 9 and the inner spring 4.

[0039] It should be noted that the combination of the technical features in the embodiments of this application is not limited to the combination methods described in the embodiments of this application or the combination methods described in specific embodiments. All technical features described in this application can be freely combined or combined in any way, unless they contradict each other.

[0040] As indicated in this application and claims, unless the context clearly indicates otherwise, the words "a," "an," and / or "the" do not specifically refer to the singular and may also include the plural. Generally speaking, the term "comprising" only indicates that it includes the explicitly identified steps and elements, which do not constitute an exclusive list, and the method or apparatus may also include other steps or elements.

[0041] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications or equivalent substitutions made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A plug for irradiated samples, characterized in that, Includes upper cylinder, pin, outer spring, inner spring, core rod, connecting rod, plug, gripping operating sleeve, and stop block. The stop block is fixed to the plug body by the pin and is configured to rotate around the pin shaft; the upper cylinder is mounted on the plug body by two pins; an outer spring is installed between the upper cylinder and the plug body, and the upper cylinder compresses the outer spring by moving up and down in the pin holes on both sides of the plug body; the inner spring is disposed in the gap between the core rod and the plug body, the core rod is connected to the connecting rod by the pin, the connecting rod is connected to the stop block by the pin, and the stop block is fixed to the plug body by the pin; The stop block is driven by the core rod and the connecting rod. When the core rod is in the upper position, the connecting rod drives the stop block to rotate clockwise around the pin and retract into the plug body. When the core rod is in the lower position, the connecting rod drives the stop block to rotate counterclockwise around the pin, and the stop block extends out of the outer surface of the plug body, interfering axially with the flange surface of the upper component to achieve self-locking. The gripping operation sleeve is threadedly connected to the core rod and installed at the center of the plug body to drive the stop block. The flange face of the internal component has a conical surface on one side and a flat surface on the other side. The stop can only act on the flat surface, so only one stop is set. The thickness of the irradiated sample well plug is greater than the thickness of the basket flange of the in-core component, so that the upper end of the irradiated sample well plug sits on the basket flange, the lower end of the irradiated sample well plug penetrates the entire thickness of the basket flange, and the stop block is opened, protruding from the outer cylinder surface of the plug and resting under the basket flange.

2. The irradiated sample well plug according to claim 1, characterized in that, The lower end of the plug is cone-shaped.

3. The irradiated sample well plug according to claim 1, characterized in that, The gripping operation sleeve is cylindrical, and multiple gaps are evenly arranged around its circumference.

4. The irradiated sample plug according to any one of claims 1 to 3, characterized in that, It also includes end caps, The end cap is fixed to the plug body by threads.

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