An irradiation sample hole plug for a pressurized water reactor irradiation sample rack

Abstract

The application provides a radiation sample hole plug for a pressurized water reactor radiation sample rack, which comprises an upper cylinder, a pin, an outer spring, an inner spring, a core rod, a wedge block and a plug body. The upper cylinder is installed on the plug body through two pins. An outer spring is installed between the upper cylinder and the plug body. The upper cylinder can move up and down in the pin hole on both sides of the plug body to compress the outer spring by moving up and down. The wedge block is installed in the square hole of the plug body and has a wedge-shaped groove in the middle, which cooperates with the wedge-shaped head of the core rod. The driving mode of the wedge block is to rely on the core rod and the inner spring. The lower end of the plug body is in the shape of a tapered head. The application improves and optimizes the structure of the plug by adapting to the existing basket structure and installation interface without changing the original design function of the radiation sample hole plug, adopts mechanical self-locking and wedge block structure, and increases the anti-impact function, so as to solve the problem of how to reduce the easy impact of the radiation sample hole plug for the pressurized water reactor in the prior art.

Description

Technical Field

[0001] This application belongs to the technical field of pressurized water reactor nuclear power units, specifically relating to an irradiation sample hole plug for an irradiation sample holder in a pressurized water reactor. 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 plugs on irradiated samples used in pressurized water reactors being easily blown out has become an urgent technical problem to be solved. Summary of the Invention

[0009] In view of this, the present application aims to provide an irradiation sample well plug for an irradiation sample holder of a pressurized water reactor. By adapting to the existing basket structure and installation interface without changing the original design function of the irradiation sample well plug, the plug structure is improved and optimized. A mechanical self-locking and wedge-type 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 for pressurized water reactor in the prior art.

[0010] This application provides an irradiation sample well plug for an irradiation sample holder of a pressurized water reactor. The irradiation sample well plug includes an upper cylinder, pins, an outer spring, an inner spring, a core rod, a wedge, and a plug body. 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. The upper cylinder can move up and down in the pin holes on both sides of the plug body to compress the outer spring. The wedge is installed in a square hole in the plug body, with a wedge-shaped groove in the middle that engages with the wedge-shaped head of the core rod. The lower end of the plug body is conical. The wedge is driven by the core rod and the inner spring. When the core rod is in the upper position, it contacts the upper contact surface of the wedge to overcome the spring force and retract the wedge; when the core rod is in the lower position, it contacts the lower contact surface of the wedge, causing the wedge to open and protrude beyond the outer cylinder surface of the plug body, achieving self-locking.

[0011] In one specific embodiment of this application, the irradiation sample holder plug for the pressurized water reactor 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, serving as a driving wedge.

[0012] In one specific embodiment of this application, the gripping operation sleeve is cylindrical with multiple gaps evenly arranged in the circumferential direction.

[0013] In one specific embodiment of this application, the irradiation sample holder plug for the pressurized water reactor also includes an end cap. The end cap is threaded onto the plug body.

[0014] The beneficial effects of this technical solution are as follows: By maintaining the structural characteristics of the original plug and adopting an internal external spring and an external plug body with a conical head structure at the lower end, it can both guide the installation and maintain the axial elastic constraint after installation in the reactor core, thus maintaining its original design function and ensuring the axial constraint of the plug after installation in the reactor core components, while also facilitating installation. Furthermore, by utilizing a single wedge to adapt to the special structural dimensions of the pressurized water reactor nuclear power unit's reactor core components, since one side of the reactor core component is a conical surface and the other side is a plane, the wedge can only act on the plane. Therefore, by adopting a structure with only one wedge, the use of a conical structure under the flange surface of the lower reactor core component of the pressurized water reactor nuclear power unit is achieved, avoiding interference with the conical surface and simultaneously achieving axial anti-ejection. The structure is simple and meets the self-locking requirements. In its natural state, relying on the compression force of the inner spring and the gravity of the core rod, the wedge block protrudes from the outer cylinder surface of the plug through the inclined contact between the core rod and the wedge block. The upper component flange limits the plug from being pushed out. At the same time, the wedge block has a spatial limiting relationship with the plug body both above and below. When water flows, the force direction is also downward, which has the safety of the structural design. Attached Figure Description

[0015] Figure 1 The diagram shows a schematic of the structure of an irradiation sample hole plug for an irradiation sample holder of a pressurized water reactor.

[0016] Figure 2 As shown Figure 1 The diagram shows the usage status of the irradiation sample hole plug for the pressurized water reactor irradiation sample holder.

[0017] Figure 3 The diagram shown is a schematic diagram of the structure of an irradiation sample hole plug for an irradiation sample holder of a pressurized water reactor according to an embodiment of this application.

[0018] Figure 4 As shown Figure 3 The diagram shows a cross-sectional view of the irradiation sample holder of a pressurized water reactor with the wedge in the irradiation sample hole plug in the extended state.

[0019] Figure 5 As shown Figure 3The diagram shows a cross-sectional view of the pressurized water reactor's irradiation sample holder with the wedge block in the irradiation sample hole plug in the retracted state.

[0020] Figure 6 As shown Figure 3 A schematic diagram of the appearance of the irradiation sample holder for the pressurized water reactor.

[0021] Figure 7 As shown Figure 3 The pressurized water reactor irradiation sample holder shown uses an irradiation sample hole plug and Figure 1 The diagram shows a comparison of the installation of irradiation sample hole plugs on the irradiation sample holder of a pressurized water reactor.

[0022] Figure 8 As shown Figure 3 The diagram shows the installation of the pressurized water reactor irradiation sample holder with the wedge in the retracted state of the irradiation sample hole plug.

[0023] Figure 9 As shown Figure 3 The diagram shows the installation of the pressurized water reactor irradiation sample holder with the wedge in the irradiation sample hole plug in the extended state.

[0024] Figure 10 As shown Figure 3 A partial structural diagram of the irradiation sample hole plug for the pressurized water reactor irradiation sample holder is shown. Detailed Implementation

[0025] 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.

[0026] At least one embodiment of this application provides an irradiation sample hole plug for an irradiation sample holder of a pressurized water reactor, see reference. Figures 1 to 10The irradiation sample holder of the pressurized water reactor uses an irradiation sample orifice plug 11 (hereinafter referred to as orifice plug 11), which includes an upper cylinder 1, pins 2, an outer spring 3, an inner spring 4, a core rod 5, a wedge block 6, and a plug body 7. 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. The upper cylinder 1 can move up and down in the pin holes on both sides of the plug body 7 to compress the outer spring 3 by moving up and down. The wedge block 6 is installed in the square hole of the plug body 7, with a wedge-shaped groove in the middle, which cooperates with the wedge head of the core rod 5. The lower end of the plug body 7 is conical. The wedge block 6 is driven by the core rod 5 and the inner spring 4. When the core rod 5 is in the upper position, it contacts the upper contact surface of the wedge block 6 to overcome the spring force of the wedge block 6 and make the wedge block 6 close; when the core rod 5 is in the lower position, it contacts the lower contact surface of the wedge block 6, causing the wedge block 6 to open and protrude from the outer cylinder surface of the plug body 7, thus achieving self-locking.

[0027] 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. In its natural state, the upper cylinder 1 is lifted up. After the plug 11 is installed, the upper internal components compress the outer spring 3 downward through the upper cylinder 1, thereby axially positioning the plug.

[0028] According to the technical solution provided in this application embodiment, by maintaining the original structural characteristics of the plug, and adopting an internal outer spring 3 and an external plug body 7 with a conical head structure at the lower end, it can both guide the installation and maintain the axial elastic constraint after installation in the reactor core, thus maintaining its original design function and ensuring the axial constraint of the plug after installation in the reactor core components, while also facilitating installation. In addition, by utilizing one wedge block 6 to adapt to the special structural dimensions of the reactor core components of the pressurized water reactor nuclear power unit, since one side of the reactor core component is a conical surface and the other side is a plane, the wedge block 6 can only act on the plane. Therefore, by adopting a structural form with only one wedge block 6, the use of a conical structure under the flange surface of the lower reactor core component of the pressurized water reactor nuclear power unit is realized, avoiding interference with the conical surface, while achieving the function of axial anti-ejection. The structure is simple and can meet the self-locking requirements. In its natural state, relying on the compression force of the inner spring 4 and the gravity of the core rod 5, the wedge 6 protrudes from the outer cylinder surface of the plug body 7 through the inclined contact between the core rod 5 and the wedge 6. The upper component flange limits the hole plug from being pushed out. At the same time, the wedge 6 has a spatial limiting relationship with the plug body 7 both above and below. When the water flow impacts, the force direction is also downward, which has the safety of the structural design.

[0029] Furthermore, see reference. Figure 7 The original plug 20 was relatively short and was installed in the mounting hole of the basket flange 30. However, the irradiation sample plug 11 used in the irradiation sample holder of the pressurized water reactor was longer, with its upper end resting on the basket flange 30 and its lower end penetrating the entire thickness of the basket flange. The wedge block 6 was spread out, protruding from the plug body 7, and resting under the basket flange to prevent water from being washed out.

[0030] In at least one embodiment of this application, the irradiation sample holder irradiation sample plug 11 of the pressurized water reactor further 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 as a driving wedge 6. 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, and the core rod 5 contacts the wedge 6, which is driven by the inclined surface of the wedge 6 to retract into the plug body 7 without protruding from the outer cylindrical surface of the plug body 7. The plug can be removed by continuing upward. That is, through the driving force transmission through the inclined surface contact between the core rod 5 and the wedge 6, the wedge 6 is retracted without interfering with the flange surface of the upper component and forming a self-locking mechanism, so that the plug can be smoothly removed upward and separated from the internal components of the reactor. In this embodiment, the core rod 5 uses a combination of internal spring and gravity to open the wedge block 6 in its natural state, protruding the outer surface of the plug. At the same time, when the plug is lifted upward, the wedge-shaped surface driving mechanism of "grabbing operation sleeve 8 - core rod 5 - wedge block 6" achieves the effect of first retracting the stop block and then removing the plug.

[0031] It should be noted that the gripping operation sleeve 8 and the core rod 5 can constitute the driving structure of the wedge 6. A schematic diagram of the wedge 6 in the retracted state is shown below. Figure 8 As shown in the diagram, the wedge 6 is installed in the extended state. Figure 9 As shown.

[0032] 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 providing multiple gaps, a gripping tool can be used to perform gripping operations.

[0033] For example, multiple neutral positions can be 3 neutral positions.

[0034] In at least one embodiment of this application, the irradiation sample holder plug 11 of the pressurized water reactor further 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 7.

[0035] 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.

[0036] 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.

[0037] 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 orifice plug for an irradiation sample holder of a pressurized water reactor, characterized in that, Includes upper cylinder, pin, outer spring, inner spring, core rod, wedge, gripping operating sleeve, and plug. 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. The upper cylinder can move up and down in the pin holes on both sides of the plug body to compress the outer spring. A wedge is installed in the square hole of the plug body, with a wedge-shaped groove in the middle that engages with the wedge head of the core rod. The wedge is driven by the core rod and the inner spring. When the core rod is in the upper position, it contacts the upper contact surface of the wedge to overcome the spring force and retract the wedge. When the core rod is in the lower position, it contacts the lower contact surface of the wedge, causing the wedge to open and protrude from the outer cylinder surface of the plug body, achieving self-locking. The lower end of the plug body is conical, and the gripping operating sleeve is connected to the core rod by a thread and installed in the center of the plug body to drive the wedge. The bottom of the internal components is a conical surface on one side and a plane on the other side. The wedge can only act on the plane, so only one wedge is set. The thickness of the irradiation sample holder's irradiation sample hole plug is greater than the thickness of the basket flange, so that the upper end of the irradiation sample holder's irradiation sample hole plug rests on the basket flange of the in-core components, and the lower end penetrates the entire thickness of the basket flange. The wedge blocks are opened up, protruding the plug body and resting under the basket flange.

2. The irradiation sample hole plug for the irradiation sample holder of the pressurized water reactor according to claim 1, characterized in that, The gripping operation sleeve is cylindrical with multiple gaps evenly arranged around its circumference.

3. The irradiation sample port plug for the irradiation sample holder of a pressurized water reactor according to claim 1 or 2, characterized in that, It also includes end caps, The end cap is fixed to the plug body by threads.

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