Core protection mechanism of pool-type research reactor, reactor cooling system and cooling method

Abstract

The present invention provides a core protection mechanism, a reactor cooling system and a cooling method for a pool-type research reactor. The core protection mechanism includes: a bubble generating device, the gas outlet of the bubble generating device is arranged in a small chamber at the bottom of the pool-type research reactor, the bubble generating device is used to generate bubbles, and the bubbles and the liquid water in the small chamber at the bottom of the reactor form a gas-liquid two-phase mixture, so that the average density on the core side is reduced, thereby increasing the static pressure difference of the fluid between the reactor pool and the core side, so that the driving force of natural circulation is increased; wherein, the core of the pool-type research reactor is immersed in the bottom of the reactor pool, the small chamber at the bottom of the reactor is located below the core and is connected to the core, and the residual heat of the core is discharged by the natural circulation of water. The present invention can be used to solve or improve the problems of flow stagnation, slow natural circulation establishment speed, and inability to quickly discharge residual heat from the core in existing research reactors.

Description

Technical Field

[0001] The present invention mainly relates to the technical field of nuclear power reactors, and in particular to a core protection mechanism of a pool-type research reactor, a reactor cooling system and a cooling method. Background Art

[0002] The pool-type research reactor is a "swimming pool" reactor for research. The core is immersed in the bottom of the reactor pool, and the residual heat of the core is discharged by the natural circulation of water. During normal operation and the initial stage of an accident, the main pump and the auxiliary pump provide forced flow driving force, and the flow direction in the core is from top to bottom. After the main pump and the auxiliary pump stop running, due to the existence of inertia, the flow direction in the core is still maintained for a period of time, but the flow rate will gradually decrease until it is close to zero. There is a certain static pressure difference between the water with lower temperature in the pool beside the reactor core and the water with higher temperature on the core side. When the inertia of the downward flow is not enough to overcome the static pressure difference, the natural circulation valve is opened, and the water in the pool beside the reactor core enters the reactor bottom chamber and mixes with the water with higher temperature on the core side. The density of the water in the reactor bottom chamber continues to increase, preventing the water with lower density in the core from entering. The flow in the core begins to reverse, and the direction changes to from bottom to top, and this direction is consistent with the buoyancy direction of the coolant (water) in the core after heating. Therefore, the circulation is established and sustainable.

[0003] In the existing technical solutions, natural circulation only relies on the static pressure difference of single-phase water between the reactor pool and the core side. The driving force is small, the establishment time is long, and flow stagnation may occur during the period. The residual heat of the core cannot be quickly discharged, which can easily cause the fuel temperature to be too high or even melted. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a core protection mechanism, a reactor cooling system and a cooling method for a pool-type research reactor, so as to solve the problem that the driving force of natural circulation in the prior art is small, resulting in the inability to quickly extract the residual heat from the core.

[0005] In order to solve the above technical problems, the present invention provides a core protection mechanism for a pool-type research reactor, comprising: a bubble generating device, wherein the gas outlet of the bubble generating device is arranged in a small chamber at the bottom of the pool-type research reactor, and the bubble generating device is used to generate bubbles, and the bubbles form a gas-liquid two-phase mixture with the liquid water in the small chamber at the bottom of the reactor, so that the average density on the core side is reduced, thereby increasing the static pressure difference of the fluid between the reactor pool and the core side, so that the driving force of natural circulation is increased; wherein, the core of the pool-type research reactor is immersed in the bottom of the reactor pool, the small chamber at the bottom of the reactor is located below the core and is connected to the core, and the residual heat of the core is discharged by the natural circulation of water.

[0006] Optionally, the reactor bottom chamber is formed by a core support structure and a reactor pool steel cladding.

[0007] Optionally, the bubble generating device includes an air source and a nozzle, the nozzle is arranged in the small chamber at the bottom of the stack, one end of the nozzle is connected to the air source, and the other end of the nozzle is provided with a plurality of air outlets.

[0008] Optionally, the gas source is arranged outside the reactor pool.

[0009] Optionally, the bubble generating device further comprises a control valve, one end of the control valve being connected to the gas outlet of the gas source, and the other end of the control valve being connected to one end of the nozzle, and the control valve being used to control the conduction or blocking between the gas source and the nozzle.

[0010] Optionally, the bubble generating device further comprises a check valve, one end of the check valve is communicated with the control valve, and the other end of the check valve is communicated with one end of the nozzle.

[0011] Optionally, the gas source includes a high-pressure gas cylinder, a gas compressor, a gas storage tank, or a combination thereof.

[0012] In order to solve the above technical problems, the present invention provides a reactor cooling system, including: a pool-type research reactor, a natural circulation valve is provided on the side wall of the bottom chamber of the pool-type research reactor, and the natural circulation valve is used to control the connection or blockage between the bottom chamber and the reactor water pool; and the core protection mechanism of the pool-type research reactor as described above.

[0013] In order to solve the above technical problems, the present invention provides a reactor cooling method, which is applied to the reactor cooling system as described above, comprising: before or at the same time as opening the natural circulation valve, opening a bubble generating device to inject bubbles into the reactor bottom chamber; the bubbles and the liquid water in the reactor bottom chamber form a gas-liquid two-phase mixture, so that the average density on the core side is reduced, thereby increasing the static pressure difference of the fluid between the reactor water pool and the core side, so that the driving force of natural circulation is increased; when the natural circulation valve is opened, under the action of the static pressure difference, the mixture is discharged upward through the core, taking away the residual heat of the core.

[0014] Compared with the prior art, the present invention has the following advantages:

[0015] The core protection mechanism, reactor cooling system and cooling method of the pool-type research reactor of the present invention utilize the negative feedback characteristic of the cavitation reactivity of the research reactor, inject bubbles into the reactor bottom chamber, and the bubbles and the liquid water in the reactor bottom chamber form a gas-liquid two-phase mixture, so that the average density on the core side is further reduced, thereby increasing the static pressure difference between the fluids between the reactor water pool and the core side, making the driving force of natural circulation greater. When the natural circulation valve is opened, under the action of the static pressure difference, the mixture is discharged upward through the core. The present invention can be used to solve or improve the problems of flow stagnation, slow natural circulation establishment speed and inability to quickly discharge residual heat from the core in existing research reactors, thereby further enhancing the safety of the research reactor. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The accompanying drawings are included to provide a further understanding of the present application. They are included and constitute a part of the present application. The accompanying drawings illustrate embodiments of the present application and together with the present specification serve to explain the principles of the present application. In the accompanying drawings:

[0017] Figure 1 is a schematic diagram of a reactor cooling system according to an embodiment of the present invention.

[0018] Figure 2 is a schematic diagram of a nozzle according to an embodiment of the present invention.

[0019] Figure 3 is a schematic diagram of a reactor cooling system according to another embodiment of the present invention.

[0020] Figure 4 is a schematic diagram of a reactor cooling system according to another embodiment of the present invention.

[0021] Figure 5 is a flow chart of a reactor cooling method according to an embodiment of the present invention.

[0022] 1 Reactor pool

[0023] 2 Free liquid surface

[0024] 3 Core

[0025] 4 small rooms at the bottom of the pile

[0026] 5Natural circulation valve

[0027] 6Core support structure

[0028] 7-pile pool steel cladding

[0029] 8 Bubble Generator

[0030] 81 nozzles

[0031] 811 air outlet

[0032] 82 Check Valve

[0033] 83 control valve

[0034] 84 High-pressure gas cylinder

[0035] 85 Gas Compressor

[0036] 86 Gas Tank DETAILED DESCRIPTION

[0037] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for the description of the embodiments. Obviously, the drawings described below are only some examples or embodiments of the present application. For ordinary technicians in this field, the present application can also be applied to other similar scenarios based on these drawings without creative work. Unless it is obvious from the language environment or otherwise explained, the same reference numerals in the figures represent the same structure or operation.

[0038] Figure 1 Schematic diagram of a reactor cooling system according to an embodiment of the present invention. Figure 1 As shown, the reactor cooling system 100 includes: a reactor water pool 1, a free liquid surface 2, a core 3, a reactor bottom chamber 4, a natural circulation valve 5, a core support structure 6, a reactor water pool steel cover 7, and a bubble generating device 8. The reactor water pool 1, the free liquid surface 2, the core 3, the reactor bottom chamber 4, the natural circulation valve 5, the core support structure 6, and the reactor water pool steel cover 7 constitute a pool-type research reactor, and the bubble generating device 8 constitutes a core protection mechanism of the pool-type research reactor.

[0039] In a pool-type research reactor, the core 3 is immersed in the bottom of the reactor pool 1, and the residual heat of the core is extracted by the natural circulation of water. As the name implies, natural circulation relies solely on the driving force of natural forces (static pressure difference caused by the density difference between the lower temperature water in the pool next to the reactor core and the higher temperature water on the core side) to establish a flow circulation. The prior art solution does not have a bubble generating device such as the present application to accelerate the establishment of the circulation. Therefore, the driving force of the natural circulation is small, the establishment time is long, and flow stagnation (zero flow) will occur during the period. The residual heat of the core cannot be quickly extracted, which can easily cause the fuel temperature to be too high or even melted.

[0040] The present application sets an outlet of the bubble generating device 8 in the reactor bottom chamber 4 to increase the density difference of the fluid between the water pool beside the reactor core and the core side, quickly establish natural circulation, shorten the flow reversal period, prevent flow stagnation, quickly remove the core waste heat, and improve the safety of the research reactor.

[0041] like Figure 1As shown, the reactor bottom chamber 4 is formed by a core support structure 6 and a reactor water pool steel cladding 7. A natural circulation valve 5 is provided on the side wall of the reactor bottom chamber 4, and the natural circulation valve 5 is used to control the connection or blocking between the reactor bottom chamber 4 and the reactor water pool 1.

[0042] The reactor bottom chamber 4 is located below the reactor core 3 and is connected to the reactor core 3. The bubble generating device 8 includes a nozzle 81 and a high-pressure gas cylinder 84. In this embodiment, the high-pressure gas cylinder 84 serves as a gas source for the bubble generating device 8. The nozzle 81 is disposed in the reactor bottom chamber 4, one end of the nozzle 81 is connected to the high-pressure gas cylinder 84, and the other end of the nozzle 81 is provided with a plurality of gas outlets. Figure 2 Schematic diagram of a nozzle according to an embodiment of the present invention. Figure 2 As shown, a plurality of gas outlets 811 are provided on the upper part of the nozzle 81. The bubble generating device 8 is used to generate bubbles, which form a gas-liquid two-phase mixture with the liquid water in the reactor bottom chamber 4, so that the average density on the core side is reduced, thereby increasing the static pressure difference of the fluid between the reactor water pool and the core side, thereby increasing the driving force of the natural circulation.

[0043] Optionally, the bubble generating device 8 further comprises a control valve 83. One end of the control valve 83 is connected to the gas outlet of the high-pressure gas cylinder 84, and the other end of the control valve 83 is connected to one end of the nozzle 81. The control valve 83 is used to control the conduction or blocking between the high-pressure gas cylinder 84 and the nozzle 81.

[0044] Optionally, the bubble generating device 8 further includes a check valve 82 . One end of the check valve 82 is communicated with the control valve 83 , and the other end of the check valve 82 is communicated with one end of the nozzle 81 .

[0045] Optionally, the check valve 82, the control valve 83 and the high-pressure gas cylinder 84 are arranged outside the reactor water pool.

[0046] Figure 3 Schematic diagram of a reactor cooling system according to another embodiment of the present invention. Figure 3 In the embodiment, the gas compressor 85 serves as the gas source of the bubble generating device 8 .

[0047] Figure 4 Schematic diagram of a reactor cooling system according to another embodiment of the present invention. Figure 4 In the embodiment, the gas compressor 85 and the gas storage tank 86 serve as the gas source of the bubble generating device 8.

[0048] The present application also provides a reactor cooling method, which is applied to the reactor cooling system of the present application. Figure 5 FIG. 1 is a flow chart of a reactor cooling method according to an embodiment of the present invention. Figure 5 As shown, the reactor cooling method 500 includes:

[0049] Step S51: before or at the same time as opening the natural circulation valve, turning on the bubble generating device to inject bubbles into the bottom chamber of the stack;

[0050] Step S52: The bubbles and the liquid water in the reactor bottom chamber form a gas-liquid two-phase mixture, which reduces the average density on the core side, thereby increasing the static pressure difference of the fluid between the reactor pool and the core side, thereby increasing the driving force of the natural circulation;

[0051] Step S53: After the natural circulation valve is opened, the mixture is discharged upward through the core under the action of the static pressure difference, taking away the residual heat of the core.

[0052] The present invention can be used to solve or improve the problems of flow stagnation, slow natural circulation establishment, and inability to quickly discharge residual heat from the core in existing research reactors, thereby further enhancing the safety of the research reactor. Secondly, the present invention utilizes the negative feedback characteristic of the cavitation reactivity of the research reactor, injects bubbles into the core, introduces negative reactivity, and makes the research reactor shutdown depth greater, further improving the safety of the research reactor.

[0053] Flowcharts are used in the present application to illustrate the operations performed by the system according to the embodiments of the present application. It should be understood that the preceding or following operations are not necessarily performed accurately in order. On the contrary, various steps may be processed in reverse order or simultaneously. At the same time, other operations may be added to these processes, or one or more operations may be removed from these processes.

[0054] The basic concepts have been described above. Obviously, for those skilled in the art, the above invention disclosure is only used as an example and does not constitute a limitation of the present application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements and amendments to the present application. Such modifications, improvements and amendments are suggested in the present application, so such modifications, improvements and amendments still belong to the spirit and scope of the exemplary embodiments of the present application.

[0055] At the same time, the present application uses specific words to describe the embodiments of the present application. For example, "one embodiment", "an embodiment", and / or "some embodiments" refer to a certain feature, structure or characteristic related to at least one embodiment of the present application. Therefore, it should be emphasized and noted that "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or more in different positions in this specification does not necessarily refer to the same embodiment. In addition, some features, structures or characteristics in one or more embodiments of the present application can be appropriately combined.

[0056] As shown in this application, unless the context clearly indicates an exception, the words "a", "an", "a kind" and / or "the" do not refer to the singular, but also include the plural. Generally speaking, the terms "include" and "comprise" only indicate the inclusion of the steps and elements that have been clearly identified, and these steps and elements do not constitute an exclusive list. The method or device may also include other steps or elements.

[0057] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps set forth in these embodiments do not limit the scope of the application. Meanwhile, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to actual proportional relationships. The technology, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be considered as a part of the specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, and therefore, once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0058] In the description of the present application, it should be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction, and therefore cannot be understood as limiting the scope of protection of the present application; the directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0059] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0060] In addition, it should be noted that the use of words such as "first" and "second" to define components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above words have no special meaning and cannot be understood as limiting the scope of protection of this application. In addition, although the terms used in this application are selected from well-known and commonly used terms, some terms mentioned in the specification of this application may be selected by the applicant at his or her discretion, and their detailed meanings are explained in the relevant parts of the description of this article. In addition, it is required to understand this application not only by the actual terms used, but also by the meaning implied by each term.

[0061] It should be understood that when a component is referred to as being "on another component," "connected to another component," "coupled to another component," or "contacting another component," it may be directly on, connected to, coupled to, or contacting the other component, or there may be intervening components. In contrast, when a component is referred to as being "directly on another component," "directly connected to," "directly coupled to," or "directly contacting" another component, there are no intervening components. Similarly, when a first component is referred to as being "electrically in contact with" or "electrically coupled to" a second component, there is an electrical path between the first component and the second component that allows current to flow. The electrical path may include capacitors, coupled inductors, and / or other components that allow current to flow, even without direct contact between conductive components.

[0062] Similarly, it should be noted that in order to simplify the description of the disclosure of this application and thus help understand one or more embodiments of the invention, in the above description of the embodiments of the present application, multiple features are sometimes combined into one embodiment, figure or description thereof. However, this disclosure method does not mean that the subject of the present application requires more features than the features mentioned. In fact, the features of the embodiment are less than all the features of the single embodiment disclosed above.

[0063] In some embodiments, numbers describing the number of components and attributes are used. It should be understood that such numbers used for the description of the embodiments are modified by the modifiers "about", "approximately" or "substantially" in some examples. Unless otherwise specified, "about", "approximately" or "substantially" indicate that the numbers are allowed to vary by ±20%. Accordingly, in some embodiments, the numerical parameters used in the specification are approximate values, which can be changed according to the required characteristics of individual embodiments. In some embodiments, the numerical parameters should take into account the specified significant digits and adopt the method of general digit retention. Although the numerical domains and parameters used to confirm the breadth of the range in some embodiments of the present application are approximate values, in specific embodiments, the setting of such numerical values ​​is as accurate as possible within the feasible range.

[0064] Although the present application has been described with reference to the current specific embodiments, ordinary technicians in this technical field should recognize that the above embodiments are only used to illustrate the present application, and various equivalent changes or substitutions may be made without departing from the spirit of the present application. Therefore, as long as the changes and modifications to the above embodiments are within the scope of the essential spirit of the present application, they will fall within the scope of the present application.

Claims

1. A core protection mechanism for a pool-type research reactor, characterized in that: include: A bubble generating device, wherein the gas outlet of the bubble generating device is arranged in the reactor bottom chamber of the pool-type research reactor, and the bubble generating device is used to generate bubbles, and the bubbles and the liquid water in the reactor bottom chamber form a gas-liquid two-phase mixture, so that the average density on the core side is reduced, thereby increasing the static pressure difference of the fluid between the reactor water pool and the core side, so that the driving force of the natural circulation is increased; The core of the pool-type research reactor is immersed in the bottom of the reactor pool, the reactor bottom chamber is located below the core and is connected to the core, and the residual heat of the core is discharged by the natural circulation of water.

2. The core protection mechanism of a pool-type research reactor according to claim 1, characterized in that: The reactor bottom chamber is formed by the core support structure and the steel covering of the reactor water pool.

3. The core protection mechanism of the pool-type research reactor according to claim 2, characterized in that: The bubble generating device comprises an air source and a nozzle, wherein the nozzle is arranged in the small chamber at the bottom of the pile, one end of the nozzle is connected to the air source, and the other end of the nozzle is provided with a plurality of air outlets.

4. The core protection mechanism of the pool-type research reactor according to claim 3, characterized in that: The gas source is arranged outside the reactor water pool.

5. The core protection mechanism of the pool-type research reactor according to claim 3, characterized in that: The bubble generating device further comprises a control valve, one end of which is connected to the gas outlet of the gas source, and the other end of which is connected to one end of the nozzle, and the control valve is used to control the conduction or blocking between the gas source and the nozzle.

6. The core protection mechanism of the pool-type research reactor according to claim 5, characterized in that: The bubble generating device further comprises a check valve, one end of which is communicated with the control valve, and the other end of which is communicated with one end of the nozzle.

7. The core protection mechanism of a pool-type research reactor according to claim 3, characterized in that: The gas source includes a high-pressure gas cylinder, a gas compressor, a gas storage tank or a combination thereof.

8. A reactor cooling system, characterized in that: include: A pool-type research reactor, wherein a natural circulation valve is provided on the side wall of a reactor bottom chamber of the pool-type research reactor, and the natural circulation valve is used to control the connection or blocking between the reactor bottom chamber and the reactor water pool; and A core protection mechanism for a pool-type research reactor as described in any one of claims 1 to 7.

9. A reactor cooling method, applied to the reactor cooling system according to claim 8, characterized in that: include: Before or at the same time as opening the natural circulation valve, the bubble generating device is turned on to inject bubbles into the bottom chamber of the reactor; The bubbles and the liquid water in the reactor bottom chamber form a gas-liquid two-phase mixture, which reduces the average density on the core side, thereby increasing the static pressure difference of the fluid between the reactor water pool and the core side, thereby increasing the driving force of the natural circulation; When the natural circulation valve is opened, the mixture is discharged upward through the core under the action of the static pressure difference, taking away the residual heat of the core.

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