Solid-state reactor core control rotary drum and heat pipe micro-reactor

Abstract

A solid reactor core control drum comprises a cladding, a reflector, an absorber and end plugs, the cladding is provided with a containing cavity, the reflector and the absorber are contained in the containing cavity, and the end plugs are arranged at the two ends of the containing cavity to form a closed state; the reflector is provided with an arc-shaped reflecting surface extending along the inner wall of the containing cavity, the absorber is provided with an arc-shaped absorbing surface extending along the inner wall of the containing cavity, and at least one end plug is provided with an air chamber communicated with the containing cavity. According to the solid reactor core control drum, the reflector and the absorber can be firmly fixed and sealed for protection, and the transmutation gas generated by irradiation is accommodated through the gas chamber, so that the influence of irradiation damage on the precision and reliability of the control drum is avoided. The invention also provides a heat pipe micro-stack.

Description

Technical Field

[0001] The invention belongs to the field of nuclear power, and in particular relates to a solid core control drum and heat pipe micro-reactor. Background Art

[0002] Heat pipe micro reactor is a new type of reactor that uses heat pipes as heat transfer structures to conduct heat generated by the reactor core. Unlike pressurized water reactors that rely on control rods to adjust reactivity, heat pipe micro reactors use the rotation of a control drum to adjust the core reactivity.

[0003] Patent CN110634579A discloses a control drum, which is provided with strong neutron absorbers and drum fuel elements in the circumferential direction. As the drum rotates, when the drum fuel elements face the core active area, the reactor has the maximum reactivity, and when the strong neutron absorbers face the core active area, the reactor has the maximum shutdown depth. The drum provided by this solution can save space for the reactor control mechanism and adjust the reactivity of the reactor.

[0004] However, as the core control mechanism, the drum is under high-temperature irradiation conditions for a long time and needs to have high radiation tolerance and reliability. As the service time of the drum increases, the radiation damage of the drum itself will gradually accumulate, and the resulting radiation swelling and transmutation gas will have an adverse effect on the reliability of the drum. The existing technical solutions lack a solution to the radiation damage of the drum, resulting in the reliability of the heat pipe micro-reactor being affected. Therefore, providing a control drum with better radiation tolerance has positive significance for improving the service life and reliability of the heat pipe micro-reactor. Summary of the invention

[0005] The purpose of the present invention is to provide a solid core control drum to improve the reliability of the control drum. The present invention also provides a heat pipe micro-reactor.

[0006] According to an embodiment of one aspect of the present invention, a solid core control drum is provided. The drum comprises:

[0007] A cladding shell, wherein the cladding shell is cylindrical and has a containing cavity;

[0008] a reflector, arranged in the accommodating cavity, made of neutron reflecting material, and having an arc-shaped reflecting surface extending circumferentially along a portion of the inner wall of the accommodating cavity, wherein the edge of the arc-shaped reflecting surface extends along the generatrix of the cladding;

[0009] an absorber, arranged in the accommodating cavity, made of neutron absorbing material, and having an arc-shaped absorbing surface extending circumferentially along a portion of the inner wall of the accommodating cavity, wherein the edge of the arc-shaped absorbing surface extends along the generatrix of the cladding;

[0010] End plugs are respectively fixedly connected to the two ends of the cladding to seal the accommodating cavity, wherein at least one end plug is provided with an air chamber communicating with the accommodating cavity.

[0011] By accommodating the reflector and the absorber in the cladding, the reflector and the absorber can be contained and contained, avoiding wear and loosening of the reflector and the absorber during long-term service; a gas chamber is set in the end plug to accommodate transmutation gases such as He produced by neutron irradiation under long-term service conditions, avoiding the risks of cracking and failure caused by gas accumulation in the drum, and improving the service life of the control drum.

[0012] Furthermore, in some embodiments, the reflector is provided with a groove, the absorber is embedded in the groove, the reflector and the absorber are spliced ​​into a columnar member, and the outer contour of the columnar member matches the accommodating cavity.

[0013] The groove structure enables the reflector and the absorber to be embedded and connected, thereby preventing circumferential relative displacement during rotation, thereby improving the control accuracy of the control drum and the reliability under long-term service conditions.

[0014] Furthermore, in some embodiments, a baffle is also provided in the accommodating cavity, the baffle is fixedly connected to the end plug and extends along the axial direction of the cladding, and the baffle is conformally matched with the groove to separate the reflector from the absorber.

[0015] The baffle can further improve the stability of the absorber fixation, avoid misalignment when the reflector and the absorber swell due to radiation, prevent diffusion or radiation reaction between the reflector and the absorber under long-term radiation conditions, and further improve the reliability of controlling the drum.

[0016] Furthermore, in some embodiments, the groove is provided with a step surface, and the step surface provides circumferential limitation for the absorbent body.

[0017] The step surface can further improve the circumferential positioning accuracy of the absorbent body and improve the control accuracy of the control drum.

[0018] Furthermore, in some embodiments, the end plug is provided with a baffle groove, and the baffle is fixedly connected to the end plug via the baffle groove.

[0019] Furthermore, in some embodiments, the baffle is fixed to the baffle groove by welding.

[0020] Furthermore, in some embodiments, the central angle of the arc-shaped absorption surface is 120°-180°.

[0021] Furthermore, in some embodiments, the end plug is connected to the cladding by welding.

[0022] Furthermore, in some embodiments, at least one of the end plugs is provided with a keyway for connecting to a driving mechanism.

[0023] According to another embodiment of the present invention, a heat pipe micro-stack is provided, which includes a fuel assembly and a control drum, wherein the control drum is a solid core control drum provided in any of the above embodiments.

[0024] The control drum of the heat pipe micro-reactor has good reliability and control accuracy, and has the ability to contain transmutation gases produced by neutron irradiation under long-term service conditions, which can effectively improve the service life and maintenance-freeness of the heat pipe micro-reactor. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic diagram of the control drum structure in one embodiment;

[0026] Figure 2 This is a schematic diagram of the cross-sectional structure of a control drum in one embodiment;

[0027] Figure 3 This is a schematic diagram of a baffle structure in one embodiment;

[0028] Figure 4 Schematic diagram of the end plug structure in one embodiment.

[0029] Meaning of the reference symbols:

[0030] 1- cladding tube;

[0031] 2- reflector;

[0032] 3- absorber;

[0033] 4- baffle;

[0034] 5-front end plug;

[0035] 6- rear end plug;

[0036] 7- baffle groove;

[0037] 8-Air chamber;

[0038] 9-Stage stage.

[0039] The purpose of the above drawings is to explain the present invention in detail so that those skilled in the art can understand the technical concept of the present invention, but it is not intended to limit the present invention. For the sake of simplicity, the above drawings only schematically illustrate the structures related to the technical features of the present invention, and do not strictly follow the actual proportions to draw the complete structure and all details. DETAILED DESCRIPTION

[0040] The present invention is further described in detail below through specific embodiments in conjunction with the accompanying drawings.

[0041] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present invention. The phrase appearing in various locations in the specification does not necessarily refer to the same embodiment, nor is it limited to mutually exclusive independent or alternative embodiments. Those skilled in the art should be able to understand that the embodiments herein may be combined with other embodiments without causing structural conflicts.

[0042] In the description of this article, unless otherwise clearly specified and limited, the technical terms "installed", "connected", "connected" and the like should be understood in a broad sense, for example, it can be a movable connection, a fixed connection or an integral connection. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of this application can be understood according to specific circumstances.

[0043] In the description of this document, terms indicating orientation or positional relationships, such as "up", "down", "left", "right", "horizontal", "vertical", "height", "length", and "width", are intended to accurately describe the embodiments and simplify the description, but are not intended to limit the parts or structures involved to have a specific orientation, be installed or operate in a specific orientation, and should not be construed as a limitation on the embodiments in this document.

[0044] In the description of this article, the terms "first", "second" and the like are only used to distinguish different objects, and cannot be understood as indicating relative importance or limiting the quantity, specific order or primary and secondary relationship of the described technical features. In the description of this article, the meaning of "plurality" is at least two.

[0045] The heat pipe micro reactor is a solid core reactor that uses heat pipes as the main heat transfer element, uses the fuel assembly matrix as the heat transfer medium, and cooperates with the characteristics of the heat pipe to complete the heat release of the nuclear fuel. Unlike the rod bundle fuel assembly of the pressurized water reactor, the heat pipe micro reactor fuel assembly does not have a guide tube inside, so the conventional pressurized water reactor reactivity control components cannot be applied to the solid core fuel assembly, and need to be designed specifically according to the characteristics of the solid core fuel assembly.

[0046] The control drum is an important reactivity control component in the heat pipe micro-reactor, which is mainly used to adjust the power output of the reactor. In the design of the heat pipe micro-reactor, the control drum changes the position of the fuel in the core relative to the neutron absorber and reflector by rotating, thereby changing the neutron flux and reactivity to control the reactor power. Because of its safety importance, the control drum must be designed to be highly reliable and take into account wear and irradiation effects (such as burnup, changes in physical properties, and gas generation).

[0047] In particular, considering the application scenarios of heat pipe micro-reactors, such as temporary deployment in space, ocean or disaster areas, there is a lack of sufficient external conditions to support. In many cases, the reactor needs to be operated for a long time with only a few operators or no one, and the requirements for the long-term operation reliability of the heat pipe micro-reactor control mechanism are further increased. However, the existing control drum scheme lacks the design to improve the reliability of the control drum and reduce the impact of radiation under long-term irradiation conditions, resulting in the reliability of the control drum not being sufficient to fully meet the application requirements of heat pipe micro-reactors.

[0048] In order to solve the above problems, an embodiment of one aspect of the present invention provides a solid core control drum, which can improve the reliability of the control drum, and especially improve the service life of the solid drum under long-term neutron irradiation conditions.

[0049] The control drum structure is as follows Figure 1 As shown, the cladding tube 1 includes end plugs arranged at both ends of the cladding tube 1, wherein the end plugs include a front end plug 5 and a rear end plug 6 connected to the driving mechanism. The cladding tube 1 is a cylindrical body as a whole and can rotate around its own axis under the drive of the driving mechanism.

[0050] Combination Figure 2 A cylindrical cavity is arranged in the cladding tube 1 as a receiving cavity, and a reflector 2 and an absorber 3 are arranged in the receiving cavity.

[0051] The reflector 2 is made of neutron reflective material. In a preferred embodiment, the reflector 2 can be made of beryllium alloy or a composite material of graphite, stainless steel and beryllium alloy. The reflector 2 has an arc-shaped reflective surface extending along the inner wall of the accommodating cavity in the cladding tube 1 in the circumferential direction, and the edge of the arc-shaped reflective surface extends along the generatrix direction of the cladding tube 1.

[0052] The absorber 3 is made of neutron absorbing material, and in different embodiments, boride or boron-containing composite material, hafnium-containing composite material, etc. The absorber 3 has an arc-shaped absorbing surface extending circumferentially along the inner wall of the accommodating cavity in the cladding tube 1, and the edge of the arc-shaped absorbing surface extends along the generatrix direction of the cladding tube 1.

[0053] In a preferred embodiment, the reflector 2 is provided with a groove, and the absorber 3 is embedded in the groove to form a circumferential fixation, so that the reflector 2 and the absorber 3 are spliced ​​into a solid part, and the outer contour of the spliced ​​solid part matches the accommodating cavity of the cladding tube 1. In a further preferred embodiment, a step surface is provided on the edge of the groove, and the step surface can form a circumferential limit for the absorber 3, so that in the process of controlling the rotation of the drum, the step surface can limit the absorber 3 to rotate together with the reflector 2, avoiding circumferential slippage that affects the control accuracy of the control drum.

[0054] In a further preferred embodiment, the cladding tube 1 is further provided with Figure 3The baffle 4 shown. The baffle 4 is conformally matched with the groove of the reflector 2, and the baffle 4 is arranged in the groove to separate the reflector 2 from the absorber 3. At the same time, the two ends of the baffle 4 are fixedly connected to the front end plug 5 and the rear end plug 6 respectively. In some embodiments, the baffle 4 can be made of zirconium alloy, stainless steel, aluminum alloy or nickel-based alloy with good high temperature performance and radiation resistance, or ceramic materials such as alumina. On the one hand, the baffle 4 can form a physical isolation between the reflector 2 and the absorber 3 to prevent diffusion or reaction between the reflector 2 and the absorber 3 under long-term irradiation conditions, and can prevent mixing when fragmented particles appear in the reflector 2 or the absorber 3 under long-term neutron irradiation conditions; on the other hand, the two ends of the baffle 4 are fixedly connected to the front end plug 5 and the rear end plug 6, which can provide sufficient circumferential drive for the reflector 2 and the absorber 3 when controlling the rotation of the drum, thereby improving the control accuracy of the control drum.

[0055] In a preferred embodiment, if Figure 4 As shown, the inner end surfaces of the front plug 5 and the rear plug 6 are also provided with baffle grooves 7 matching the baffle 4, and the baffle grooves 7 can cooperate with the baffle 4 and provide position limiting. In a further preferred embodiment, the baffle 4 is fixedly connected to the baffle grooves 7 by welding.

[0056] The front end plug 5 and the rear end plug 6 are fixedly connected to the cladding tube 1 by welding, and form a seal for the accommodating cavity to prevent the external gas environment from causing oxidative corrosion to the reflector 2 and the absorber 3, and prevent the leakage of radioactive products in the cladding tube 1.

[0057] In a preferred embodiment, Figure 4 Taking the rear end plug 6 as an example, a gas chamber 8 is provided in the rear end plug 6, and the gas chamber 8 is interconnected with the accommodation cavity of the cladding tube 1. When the reflector 2 or the absorber 3 captures neutrons and releases transmuted gas under long-term neutron irradiation conditions, for example, gaseous He atoms are generated after part of the neutron absorbing material captures neutrons, and the transmuted gas can be contained in the gas chamber 8, so as to prevent the cladding tube 1 from swelling or rupture due to excessive pressure, and improve the reliability of controlling the drum.

[0058] In a preferred embodiment, a keyway is provided on the front end plug 5, and the keyway is used to connect with the drum driving mechanism to allow the driving mechanism to drive and control the overall rotation of the drum. Figure 4 The rear end plug 6 is provided with a step 9, and the front end plug 5 is correspondingly provided with a stepped shaft to cooperate with the installation of bearings so that the control drum can rotate around its own axis.

[0059] The control drum can be used for the reactivity control of the heat pipe micro-reactor. Multiple control drums are installed on the periphery of the solid core of the heat pipe micro-reactor, and the reactivity can be adjusted by rotating the control drum. When the control drum rotates to the point where the reflector 2 faces the core active area, the neutrons in the core are reflected back to the core active area, and the reactivity is improved; when the control drum rotates to the point where the absorber 3 faces the core active area, the neutrons in the core are absorbed by the absorber 3, and the reactivity is reduced. In a preferred embodiment, the central angle corresponding to the arc-shaped absorption surface of the absorber 3 is 120°, that is, the arc-shaped absorption surface occupies 1 / 3 of the circumferential range of the inner wall of the accommodating cavity in the cladding tube 1.

[0060] The control drum provided in the above embodiment has the following advantages:

[0061] Precise reactivity control: The control drum provided in the embodiment of the present invention adjusts the relative position of the fuel, absorber 3 and reflector 2 in the core by rotation, thereby precisely controlling the neutron flux and reactivity. This design makes the control of reactor power output more flexible and precise, and is particularly suitable for solid core reactors, making up for the shortcomings of conventional pressurized water reactor control components in heat pipe micro-reactors.

[0062] Reliable structure: The structural design of the control drum fully considers the fuel consumption, irradiation effect and physical property changes during operation. The absorber 3 and reflector 2 always maintain a relatively stable position through the sealing and fixation of the rear end plug 6, baffle 4, cladding tube 1 and other components. This design improves the stability and durability of the structure, and is particularly suitable for long-term operation of nuclear reactors.

[0063] High safety: The design of the control drum fully considers the nuclear safety requirements. The gas chamber 8 is set inside the end plug to accommodate the fission gas, which reduces the impact of gas expansion on the device structure and effectively improves the safety of the system. In addition, the packaging and fixation of the absorber 3 and the reflector 2 ensure that the components will not fail under extreme working conditions.

[0064] Consideration of wear and radiation effects: The design of the control drum takes into account the wear of components caused by radiation and fuel consumption during long-term operation. The design of the groove and the baffle groove 7 can effectively fix the absorber 3 and the reflector 2 to avoid vibration or looseness during operation, which is particularly important for long-term stable operation.

[0065] Structural design of absorber 3 and reflector 2: The absorber 3 is designed to be an arc of approximately 120°-180° and is embedded in the periphery of the reflector 2. This geometric structure design enables the absorber 3 to flexibly adjust its relative position to the core, thereby achieving efficient neutron absorption control and improving the accuracy of reactor power regulation.

[0066] The packaging design of the control drum cladding tube: the cladding tube 1 is a thin-walled cylindrical structure, and the absorber 3 and the reflector 2 are completely encapsulated by a welding process. This feature ensures the sealing of the components during the operation of the reactor, avoids external interference, and increases the safety and stability of the system.

[0067] End plug and baffle groove 7 design: The baffle groove 7 fixes the absorber 3 and reflector 2 in a suitable position to avoid movement or wear during operation, while providing a gas discharge space. This structural design can effectively alleviate the cumulative impact of fission gas and improve the safety and service life of the overall device.

[0068] The heat pipe micro-reactor using the solid-state core controlled drum provided by the above embodiment has better reliability and service life, can operate stably for a long time in an unmanned state, effectively improves the convenience of heat pipe micro-reactor deployment, and broadens the application scenarios of heat pipe micro-reactors.

[0069] The purpose of the above embodiments is to further explain the present invention in detail in conjunction with the accompanying drawings so that those skilled in the art can understand the technical concept of the present invention. Within the scope of the present invention, the optimization or equivalent replacement of the part structure involved, and the combination of the implementation methods in different embodiments without conflict of structure and principle, all fall within the protection scope of the present invention.

Claims

1. A solid core control drum, characterized in that: include: A cladding shell, wherein the cladding shell is cylindrical and has a containing cavity; a reflector, arranged in the accommodating cavity, made of neutron reflecting material, and having an arc-shaped reflecting surface extending circumferentially along a portion of the inner wall of the accommodating cavity, wherein the edge of the arc-shaped reflecting surface extends along the generatrix of the cladding; an absorber, arranged in the accommodating cavity, made of neutron absorbing material, and having an arc-shaped absorbing surface extending circumferentially along a portion of the inner wall of the accommodating cavity, wherein the edge of the arc-shaped absorbing surface extends along the generatrix of the cladding; End plugs are respectively fixedly connected to the two ends of the cladding to seal the accommodating cavity, wherein at least one end plug is provided with an air chamber communicating with the accommodating cavity.

2. The solid core control drum according to claim 1, characterized in that: The reflector is provided with a groove, the absorber is embedded in the groove, the reflector and the absorber are spliced ​​into a columnar member, and the outer contour of the columnar member matches the accommodating cavity.

3. The solid core control drum according to claim 2, characterized in that: A baffle is also provided in the accommodating cavity. The baffle is fixedly connected to the end plug and extends along the axial direction of the cladding. The baffle is conformally matched with the groove to separate the reflector from the absorber.

4. The solid core control drum according to claim 2 or 3, characterized in that: The groove is provided with a step surface, and the step surface provides circumferential limitation for the absorbent body.

5. The solid core control drum according to claim 2 or 3, characterized in that: The end plug is provided with a baffle groove, and the baffle is fixedly connected to the end plug through the baffle groove.

6. The solid core control drum according to claim 5, characterized in that: The baffle is welded and fixed to the baffle groove.

7. The solid core control drum according to claim 1, 2 or 3, characterized in that: The central angle of the arc-shaped absorption surface is 120°-180°.

8. The solid core control drum according to claim 1, 2 or 3, characterized in that: The end plug is connected to the cladding by welding.

9. The solid core control drum according to claim 1, 2 or 3, characterized in that: At least one of the end plugs is provided with a keyway for connection with a drive mechanism.

10. A heat pipe micro-reactor, comprising a fuel assembly and a control drum, characterized in that: The control drum is configured as a solid core control drum as claimed in any one of claims 1 to 9.

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