An irradiation sample hole plug for an irradiation sample rack of a nuclear power plant

Abstract

The application provides an irradiation sample hole plug for an irradiation sample frame of a nuclear power unit, which comprises an upper cylinder, a pin, an outer spring, an inner spring, a core rod, a hook claw spring, a plug body and a hook claw. 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 to compress the outer spring through the pin holes on both sides of the plug body. The inner spring is arranged at a gap between the core rod and the plug body. The hook claw is fixed on the plug body through the pin and is configured to rotate around the pin shaft, and the driving mode of the hook claw is to rely on the core rod and the hook claw spring. The application adopts mechanical self-locking, optimizes the structure without changing the original design, adopts the hook claw structure, and increases the anti-impact-out function, so as to solve the problem of how to reduce the impact-out of the irradiation sample hole plug in the prior art.

Description

Technical Field

[0001] This application belongs to the technical field of irradiated sample hole plugs for nuclear power plants, and specifically relates to an irradiated sample hole plug for use on an irradiated sample holder in a nuclear power unit. 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 hole plug for an irradiation sample holder in a nuclear power unit. It adopts a mechanical self-locking mechanism and optimizes the structure without changing the original design. It adopts a claw-type structure and adds an anti-blowout function to solve the problem of how to reduce the easy blowout of the irradiation sample hole plug in the prior art, which has become an urgent technical problem to be solved.

[0010] This application provides an irradiation sample well plug for an irradiation sample holder in a nuclear power unit, comprising an upper cylinder, pins, an outer spring, an inner spring, a core rod, a hook spring, a plug body, and hooks. The upper cylinder is mounted on the plug body via 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 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 hooks are fixed to the plug body by pins and configured to rotate around the pin axis. The hooks are driven by the core rod and the hook spring. When the core rod is in the upper position, it contacts the upper contact surface of the hook to overcome the hook spring force and retract the hook; when the core rod is in the lower position, it contacts the lower contact surface of the hook to open the hook and 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 irradiation sample well plug on the irradiation sample holder for a nuclear power unit 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 drive the claw.

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

[0015] In one specific embodiment of this application, the irradiation sample well plug on the irradiation sample holder for a nuclear power unit 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 pore plug, it adapts to the existing basket structure and installation interface, improves the pore plug structure, adds anti-explosion function, and adopts an active locking mechanical 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 schematic diagram of the structure of an irradiation sample hole plug for an irradiation sample holder in a nuclear power unit, provided in an embodiment of this application.

[0020] Figure 4 As shown Figure 3 The diagram shows a cross-sectional view of the irradiation sample hole plug on the irradiation sample holder for nuclear power units with the hooks extended.

[0021] Figure 5 As shown Figure 3 The diagram shows a cross-sectional view of the irradiation sample hole plug on the irradiation sample holder for nuclear power units with the hooks retracted.

[0022] Figure 6 The image shown is an external view of an irradiation sample hole plug for an irradiation sample holder in a nuclear power unit, according to an embodiment of this application.

[0023] Figure 7 As shown Figure 3 The irradiation sample hole plug shown is on the irradiation sample holder for nuclear power units. 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 irradiation sample hole plug on the irradiation sample holder for nuclear power units with the claws retracted.

[0025] Figure 9 As shown Figure 3 The diagram shows the installation of the irradiation sample hole plug on the irradiation sample holder for nuclear power units with the claws extended.

[0026] Figure 10 As shown Figure 3 The diagram shows the structure of the hook in the irradiation sample hole plug on the irradiation sample holder used in nuclear power units.

[0027] Figure 11 As shown Figure 3 The diagram shows the structure of the core rod in the irradiation sample hole plug on the irradiation sample holder used in nuclear power units.

[0028] Figure 12 As shown Figure 3 The diagram shows a schematic of the structure of the irradiation sample holder used in nuclear power units, which is used to grasp the operation sleeve in the irradiation sample hole plug. Detailed Implementation

[0029] 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.

[0030] At least one embodiment of this application provides an irradiation sample well plug (hereinafter referred to as well plug) for use on an irradiation sample holder in a nuclear power plant, see reference. Figures 3 to 12 The irradiation sample port plug 11 for use on an irradiation sample holder in a nuclear power unit includes an upper cylinder 1, pins 2, an outer spring 3, an inner spring 4, a core rod 5, a hook spring 6, a plug body 7, and a hook 10. The upper cylinder 1 is mounted on the plug body 7 via 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 through 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 hook 10 is fixed to the plug body 7 by pins 2 and is configured to rotate around the pin shaft. The hook 10 is driven by the core rod 5 and the hook spring 6. When the core rod 5 is in the upper position, it contacts the upper contact surface of the hook 10 to overcome the spring force of the hook 10 and cause the hook 10 to retract; when the core rod 5 is in the lower position, it contacts the lower contact surface of the hook 10, causing the hook 10 to open and achieve self-locking.

[0031] It should be noted that the plug body 7 is the main structural component of the entire plug 11, providing a structural framework for other components.

[0032] According to the technical solution provided in this application, a single hook 10 is used to adapt to the special structural dimensions of the internal components of a pressurized water reactor nuclear power unit. Since one side of the internal component is a conical surface and the other side is a flat surface, the hook can only act on the flat surface. Therefore, only one hook is set, which is simple in structure and can meet the self-locking requirements. This realizes the use of the conical structure under the flange surface of the lower internal component of the nuclear power unit, avoids interference with the conical surface, and achieves the function of axial anti-explosion. An outer spring 3 is installed at the upper end to maintain the axial constraint of the plug 11 after it is installed in the internal component. In addition, in the natural state, the upper cylinder 1 is lifted up. After the plug 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.

[0033] Furthermore, in its natural state, the hook 10 is opened by the "dual action" of the core rod 5 and the hook spring 6, hooking the flange face of the lower component to prevent it from being pushed out. After the plug is installed in place, the core rod 5 moves downward under the action of the inner spring 4. Through the cooperation of the contact surface between the core rod 5 and the hook 10, the hook 10 is opened outward. At the same time, the hook spring 6 also assists in opening the hook 10, forming a "double insurance" for opening the hook 10. That is, by using the "double insurance" of the core rod inner spring 4 and the hook spring 6, the opening of the hook 10 in its natural state is achieved.

[0034] In at least one embodiment of this application, the thickness of the irradiated sample well plug is greater than the thickness of the basket flange. (Reference) Figure 7 The upper end of the plug 11 rests on the basket flange 30, and the lower end of the plug 11 penetrates the entire thickness of the basket flange. The hook 10 is spread out, protruding from the plug body 7 and resting under the basket flange 30. Thus, the original plug 20 is shorter and installed in the mounting hole of the basket flange 30, while the plug 11 provided in this embodiment is longer. By setting the thickness of the irradiated sample plug 11 to be greater than the thickness of the basket flange 30, when the irradiated sample plug 11 is installed, the upper end of the irradiated sample plug 11 rests on the basket flange 30, and the lower end penetrates the entire thickness of the basket flange, further preventing water from being flushed out.

[0035] In at least one embodiment of this application, the lower end of the plug 7 is cone-shaped. Thus, by adopting an internal external spring and an external cone-shaped lower end structure, the structural characteristics and design functions of the original plug are maintained, making the irradiation sample plug for the irradiation sample holder of the nuclear power unit suitable for pressurized water reactor nuclear power units, easy to install, and able to both guide the installation and maintain axial elastic constraint after installation in the reactor.

[0036] In at least one embodiment of this application, reference is made to Figure 4 and Figure 5 The irradiation sample well plug for the irradiation sample holder in a nuclear power unit 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, serving to drive the hook 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 upwards, the gripping operation sleeve 8 drives the core rod 5 upwards, and the core rod 5 contacts the upper contact surface of the hook 10, causing the hook 10 to rotate counterclockwise around the pin shaft. The lower end of the hook 10 retracts, and the well plug 11 can be removed by continuing upwards. This embodiment of the application uses an interlocking structure between the gripping operation sleeve 8 and the core rod 5 to achieve the operation of the hook 10 retracting first when removing the well plug 11.

[0037] Specifically, when removing the plug 11, the claw 10 retracts first. The plug is removed remotely using a long-handled tool. The gripping tool works in conjunction with the gripping operation sleeve 8. Lifting the gripping operation sleeve 8 drives the core rod 5 to retract the claw, allowing the plug to be lifted smoothly and separated from the internal components of the reactor.

[0038] 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.

[0039] For example, multiple neutral positions are 3 neutral positions.

[0040] In at least one embodiment of this application, reference is made to Figure 4 and Figure 5 The irradiation sample well plug for the irradiation sample holder used in nuclear power units also includes an end cap 9. The end cap 9 is fixed to the plug body 7 by threads. Thus, through the limiting action of the end cap 9 and the inner spring 4, the core rod 5 can move up and down within a certain range at the center of the plug body.

[0041] 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.

[0042] 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.

[0043] 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. An irradiation sample hole plug for use in an irradiation sample holder of a nuclear power plant, characterized in that, Include upper cylinder, pin, outer spring, inner spring, core rod, hook claw spring, plug body, hook and grab operation sleeve, 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, the upper cylinder compresses the outer spring by moving up and down in the pin hole on both sides of the plug body, the inner spring is arranged at the gap between the core rod and the plug body; The hook is fixed on the plug body through the pin, and the hook is configured to rotate around the pin shaft; The grab operation sleeve is connected with the core rod through threads and is installed in the center of the plug body to drive the hook; The driving mode of the hook is to rely on the core rod and the hook spring, the core rod is in contact with the upper contact surface of the hook when it is in the upper position, so as to overcome the hook spring force and make the hook close; The core rod is in contact with the lower contact surface of the hook when it is in the lower position, so as to make the hook open and realize self-locking; The lower side of the lower part of the in-pile component is a conical surface, and the other side is a flat surface, the hook can only act on the flat surface, so only one hook is arranged; The thickness of the irradiation sample hole plug is greater than the thickness of the basket flange, so that the upper end of the irradiation sample hole plug is seated on the basket flange of the in-pile component, the lower end of the irradiation sample hole plug penetrates through the entire thickness of the basket flange, the hook is opened and protrudes from the plug body, and bears on the lower surface of the basket flange.

2. The irradiation sample hole plug according to claim 1, wherein, The lower end of the plug body is conical.

3. The irradiation sample hole plug according to claim 1, wherein, The grab operation sleeve is cylindrical, and a plurality of empty stops are uniformly arranged in the circumferential direction of the grab operation sleeve.

4. The irradiation sample well plug of any one of claims 1 to 3, wherein, Further comprising an end cover, Wherein, the end cover is fixed on the plug body through threads. Further comprising an end cover, Wherein, the end cover is fixed on the plug body through threads.

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