Cooling circulation loop and marine natural circulation cooling system

Abstract

The present application relates to reactor cooling technical field, provide a kind of cooling circulation loop and marine natural circulation cooling system.Cooling circulation loop, comprising: first cold pipe, second cold pipe, hot pipe, heat exchanger and storage chamber;Phase-change heat storage particles with density less than seawater are provided in storage chamber;Heat exchanger is provided with riser, one end of first cold pipe is connected with the inlet end of riser, the other end of first cold pipe is used to be connected with hot hydrazine seawater, one end of second cold pipe is connected with storage chamber, the other end of second cold pipe is used to be connected with hot hydrazine seawater, storage chamber is provided with discharge port, discharge port is connected with the inlet end of riser, one end of hot pipe is connected with the outlet end of riser, the other end of hot pipe is used to be connected with hot hydrazine seawater.The cooling circulation loop and marine natural circulation cooling system provided by the present application solve the defect that the way of increasing bubble lifting device in the ascending section of natural circulation system in the prior art cannot greatly enhance the heat transfer capacity of natural circulation.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of reactor cooling, in particular to a cooling circulation loop and a marine natural circulation cooling system. BACKGROUND

[0002] After the reactor is shut down, the core will still generate residual heat, which may cause the fuel rod cladding to melt if it cannot be promptly discharged, thereby causing radioactive material leakage and threatening the safety of personnel and equipment. In order to solve the problem of residual heat discharge after the reactor is shut down, the system designs a natural circulation cooling system connected with thermal hydrazine seawater, which uses the density difference of the fluid to drive the circulation flow of the coolant to conduct the residual heat to the thermal hydrazine seawater. However, due to the limited space of the system, the height difference of the cold and hot sources of the natural circulation cooling system is insufficient, resulting in low heat transfer capacity. In addition, in the early stage of the reactor shutdown, due to the high residual heat power of the core, the natural circulation system will face a large thermal shock, and severe boiling phenomenon may occur in the loop, thereby causing large pressure pulsation and flow oscillation, which will threaten the safety of the core and affect the stability of the offshore platform.

[0003] In view of the problem of insufficient heat transfer capacity of the natural circulation system caused by the effective height difference of the cold and hot sources, the common method at present is to increase the bubble lifting device in the ascending section of the natural circulation system, which reduces the density of the fluid in the rising pipe by injecting bubbles, so as to increase the density difference of the system cold and hot pipes and enhance the heat transfer capacity of the natural circulation. However, due to the limited space in the system, the height of the ascending section of the natural circulation system is very small, which results in little effect of this method on enhancing the heat transfer capacity of the natural circulation. If bubbles are injected from the inlet of the heat exchanger, the bubbles may adhere to the heat transfer wall to cause heat transfer deterioration, which endangers the safety of the system. SUMMARY

[0004] The present application provides a cooling circulation loop and a marine natural circulation cooling system to solve the defect that the method of increasing the bubble lifting device in the ascending section of the natural circulation system cannot greatly enhance the heat transfer capacity of the natural circulation in the prior art.

[0005] In one aspect, the present application provides a cooling circulation loop, comprising: a first cold pipe, a second cold pipe, a hot pipe, a heat exchanger and a storage chamber.

[0006] The storage chamber is provided with phase change heat storage particles, the density of the phase change heat storage particles is less than that of seawater, and the phase change heat storage particles can change from solid to liquid at a set temperature.

[0007] The heat exchanger is provided with a riser pipe, one end of the first cold pipe is connected with an inlet end of the riser pipe, the other end of the first cold pipe is used for connecting with hot hydrazine seawater, one end of the second cold pipe is connected with the storage chamber, the other end of the second cold pipe is used for connecting with hot hydrazine seawater, the storage chamber is provided with a discharge port, the discharge port is connected with the inlet end of the riser pipe, so that the phase change heat storage particles in the storage chamber are sent into the riser pipe through the hot hydrazine seawater, one end of the heat pipe is connected with an outlet end of the riser pipe, and the other end of the heat pipe is used for connecting with hot hydrazine seawater.

[0008] According to the cooling circulation loop provided by the application, the first cold pipe is located above the second cold pipe, and the riser pipe is located above the storage chamber.

[0009] According to the cooling circulation loop provided by the application, the discharge port is located on a side of the storage chamber facing the riser pipe, and the inner diameter of the discharge port gradually decreases to form a necked shape, so as to guide the phase change heat storage particles.

[0010] According to the cooling circulation loop provided by the application, the ratio of the particle size of the phase change heat storage particles to the inner diameter of the riser pipe is 0.01 to 0.1.

[0011] According to the cooling circulation loop provided by the application, the phase change heat storage particles include at least one of aliphatic compounds.

[0012] According to the cooling circulation loop provided by the application, the first cold pipe is provided with a first control valve.

[0013] According to the cooling circulation loop provided by the application, the second cold pipe is provided with a second control valve.

[0014] According to the cooling circulation loop provided by the application, the heat pipe is provided with a third control valve.

[0015] According to the cooling circulation loop provided by the application, the heat exchanger is a partition wall type heat exchanger.

[0016] Another aspect of the application provides a marine natural circulation cooling system, which comprises a reactor and the cooling circulation loop as claimed in any one of the above, and the reactor is connected with the heat exchanger.

[0017] The principle of the cooling circulation loop and the marine natural circulation cooling system provided by the application is as follows.

[0018] When the marine floating platform is shut down, the marine natural circulation cooling system is put into use, the heat of the reactor is transmitted to the heat exchanger, the temperature of the fluid in the riser pipe gradually increases under the heating of the heat side of the heat exchanger, the density gradually decreases, and the thermal hydrazine seawater in the sea is driven by the density difference between the seawater and the fluid in the riser pipe to form a cooling circulation through the first cold pipe, the riser pipe and the heat pipe. At the same time, when the natural circulation cooling system is put into use at the initial stage of shutdown, the phase change heat storage particles in the storage chamber enter the riser pipe of the heat exchanger under the driving action of seawater. Since the injected phase change heat storage particles have a smaller density than seawater, the phase change heat storage particles flow into the riser pipe under the action of buoyancy and reduce the density of the mixed fluid in the heat exchange pipe. Since the density difference between the heat pipe of the heat exchanger and seawater increases, the driving force of the cooling circulation loop is enhanced, and the natural circulation flow is increased, thereby indirectly weakening the boiling phenomenon of the fluid in the riser pipe of the heat exchanger, thereby achieving the problem of inhibiting the system pressure pulsation and flow oscillation caused by the violent boiling of the heat exchanger. And since the injected phase change heat storage particles are fine solid particles, before the solid phase heat storage material melts, the solid phase heat storage material particles can disturb the near-wall heat transfer boundary layer of the riser pipe of the heat exchanger, thereby strengthening the heat exchange effect of the heat exchanger, and will not cause heat transfer deterioration phenomenon like bubbles adhering to the heat transfer wall.

[0019] The cooling circulation loop and the marine natural circulation cooling system provided by the application can inhibit the system pressure pulsation and flow oscillation caused by the violent boiling of the heat exchanger, strengthen the heat exchange effect of the heat exchanger, and solve the defect that the method of increasing the bubble lifting device in the riser pipe of the natural circulation system cannot greatly enhance the natural circulation heat transfer capacity in the prior art.

[0020] Additional aspects and advantages of the application will be described in part below, will become apparent from the following description, or will be learned by practice of the application. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are some embodiments of the application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0022] Figure 1 is a schematic diagram of the cooling circulation loop provided by the embodiment of the application.

[0023] Reference signs:

[0024] 1. first cold pipe; 2. second cold pipe; 3. heat pipe; 4. heat exchanger; 5. storage chamber; 6. phase change heat storage particles; 7. riser pipe; 8. first control valve; 9. second control valve; 10. third control valve. DETAILED DESCRIPTION

[0025] In order to make the objects, technical solutions and advantages of the present application clearer, the technical solutions in the present application will be clearly and completely described below with reference to the drawings in the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all of them. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0026] In the description of the embodiments of the present application, it should be noted that the orientations or positional relationships indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like are based on the orientations or positional relationships shown in the drawings, and are only for the purpose of facilitating the description of the embodiments of the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the embodiments of the present application. In addition, the terms "first", "second", "third" are only for the purpose of description, and cannot be understood as indicating or implying relative importance.

[0027] In the description of the embodiments of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "connected", "connected" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meaning of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0028] In the embodiments of the present application, unless otherwise explicitly specified and limited, the first feature is "on" or "under" the second feature, which can be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature "above", "above" and "above" the second feature can be that the first feature is directly above or obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "below" and "below" the second feature can be that the first feature is directly below or obliquely below the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.

[0029] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the embodiments of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, the person skilled in the art can combine and combine the different embodiments or examples described in the present specification and the features of the different embodiments or examples without contradiction.

[0030] The following will be described in combination with Figure 1 The cooling circulation loop and the marine natural circulation cooling system provided by the embodiments of the present application are described.

[0031] Referring to Figure 1 The cooling circulation loop provided by the embodiments of the present application comprises a first cold pipe 1, a second cold pipe 2, a heat pipe 3, a heat exchanger 4 and a storage chamber 5.

[0032] The storage chamber 5 is provided with phase change heat storage particles 6, the density of the phase change heat storage particles 6 is less than that of seawater, and the phase change heat storage particles 6 can change from solid state to liquid state at a set temperature.

[0033] The heat exchanger 4 is provided with a riser 7, the riser 7 is used for heat exchange with the hot side of the heat exchanger, one end of the first cold pipe 1 is connected with the inlet end of the riser 7, the other end of the first cold pipe 1 is used for connecting with hot hydrazine seawater, one end of the second cold pipe 2 is connected with the storage chamber 5, the other end of the second cold pipe 2 is used for connecting with hot hydrazine seawater, the storage chamber 5 is provided with a discharge port, the discharge port is connected with the inlet end of the riser 7, so as to send the phase change heat storage particles 6 in the storage chamber 5 into the riser 7 through the hot hydrazine seawater, one end of the heat pipe 3 is connected with the outlet end of the riser 7, and the other end of the heat pipe 3 is used for connecting with hot hydrazine seawater.

[0034] The cooling circulation loop and the marine natural circulation cooling system provided by the present application can inhibit the system pressure pulsation and flow oscillation problems caused by the violent boiling of the heat exchanger 4 in the system, and can strengthen the heat exchange effect of the heat exchanger 4, so as to solve the defect that the way of increasing the bubble lifting device in the ascending section of the natural circulation system in the prior art cannot greatly enhance the natural circulation heat transfer capacity.

[0035] Specifically, when the marine floating platform is shut down, the marine natural circulation cooling system is put into use, the heat of the reactor is transferred to the heat exchanger 4, the temperature of the fluid in the riser 7 gradually rises under the heating of the hot side of the heat exchanger 4, the density gradually decreases, and the hot hydronium seawater in the sea is driven by the density difference between the seawater and the fluid in the riser 7 to form a cooling circulation through the first cold pipe 1, the riser 7, and the heat pipe 3 and finally return to the seawater. At the same time, when the natural circulation cooling system is put into use at the initial stage of shutdown, the phase change heat storage particles 6 in the storage chamber 5 enter the riser 7 of the heat exchanger 4 under the driving action of the seawater. Since the injected phase change heat storage particles 6 have a smaller density than seawater, the phase change heat storage particles 6 flow into the riser 7 under the action of buoyancy and reduce the density of the mixed fluid in the heat pipe 3. Since the density difference between the heat pipe 3 of the heat exchanger 4 and the seawater increases, the driving force of the cooling circulation loop is enhanced, and the natural circulation flow is increased, thereby indirectly weakening the boiling phenomenon of the fluid in the riser 7 of the heat exchanger 4, thereby achieving the purpose of inhibiting the system pressure pulsation and flow oscillation problem caused by the violent boiling of the heat exchanger 4. Moreover, since the injected phase change heat storage particles 6 are fine solid particles, before the solid phase heat storage material is heated and melted, the solid phase heat storage material particles can disturb the near-wall heat transfer boundary layer of the riser 7 of the heat exchanger 4, thereby strengthening the heat exchange effect of the heat exchanger 4 and preventing the heat transfer from being deteriorated due to the bubbles adhering to the heat transfer wall.

[0036] The heat exchanger 4 is a partitioned heat exchanger 4, which includes a heating side and a riser 7 side. The heating side is used to absorb the heat of the reactor and transfer the heat to the riser 7 side, and the riser 7 side finally transfers the heat to the hot hydronium seawater, thereby achieving the purpose of reactor cooling. The partitioned heat exchanger 4 includes a shell side heat exchanger 4, a plate heat exchanger 4, a tube and shell heat exchanger 4, etc.

[0037] The phase change heat storage particles 6 can adopt at least one of aliphatic compounds (such as paraffin). That is, the phase change heat storage particles 6 can adopt any one or a mixture of any multiple of aliphatic compounds.

[0038] As a preferred embodiment, the phase change heat storage particles 6 are paraffin particles. After entering the riser 7 of the heat exchanger 4, the paraffin (mainly composed of n-alkanes, with a melting point usually between 40°C and 60°C) can be melted and mixed with seawater due to the seawater temperature in the riser 7 being higher than the melting point of the paraffin, thereby forming a mixed fluid with a smaller density than seawater.

[0039] Referring to Figure 1As shown, according to some embodiments of the present application, the first cold pipe 1 is located above the second cold pipe 2, and the riser pipe 7 is located above the storage chamber 5. Since the density of the phase change heat storage particles 6 is less than that of seawater, by locating the first cold pipe 1 above the second cold pipe 2 and locating the riser pipe 7 above the storage chamber 5, the phase change heat storage particles 6 in the storage chamber 5 can be automatically lifted into the riser pipe 7 of the heat exchanger 4 by seawater without the need of setting other driving devices.

[0040] Specifically, when the natural circulation cooling system is put into use at the initial stage of shutdown, seawater can be introduced into the storage chamber 5 by opening the valve, and when the storage chamber 5 is filled with seawater, the phase change heat storage particles 6 can be driven into the storage chamber 5 of the heat exchanger 4 under the action of buoyancy.

[0041] In specific implementation, a charging pipe communicating with the storage chamber 5 can be provided, and when the phase change heat storage particles 6 in the storage chamber 5 are used up, the storage chamber 5 can be charged by means of pressurization or the like.

[0042] Referring to Figure 1 As shown, according to some embodiments of the present application, the discharge port is located on the side of the storage chamber 5 facing the riser pipe 7, and the inner diameter of the discharge port gradually decreases to form a conical shape to guide the phase change heat storage particles 6. By setting the discharge port to have a conical shape with a gradually decreasing inner diameter, the phase change heat storage particles 6 in the storage chamber 5 can be converged, which facilitates the introduction of the phase change heat storage particles 6 into the riser pipe 7 of the heat exchanger 4.

[0043] Referring to Figure 1 As shown, according to some embodiments of the present application, the ratio of the particle size of the phase change heat storage particles 6 to the inner diameter of the riser pipe 7 is 0.01 to 0.1. By controlling the ratio of the particle size of the phase change heat storage particles 6 to the inner diameter of the riser pipe 7 to be within the range of 0.01 to 0.1, the injected phase change heat storage particles can not only strengthen the heat exchange in the heat exchange pipe, but also avoid the blockage of the flow channel.

[0044] For example, the inner diameter of the riser pipe 7 is 20 mm, and the particle size of the phase change heat storage particles 6 is 0.2 mm to 2 mm.

[0045] Referring to Figure 1 As shown, according to some embodiments of the present application, the first control valve 8 is arranged on the first cold pipe 1. By arranging the first control valve 8 on the first cold pipe 1, the conduction or shutdown of the first cold pipe 1 can be controlled. When the marine natural circulation cooling system is not put into use, the first cold pipe 1 can be closed by the first control valve 8 to prevent seawater from entering the first cold pipe 1, and when the offshore floating platform is shut down, the natural circulation cooling system is put into use, at which time the first control valve 8 can be opened to introduce seawater with a lower temperature into the first cold pipe 1. In addition, by adjusting the opening degree of the first control valve 8, the inflow of seawater can also be adjusted to adapt to the current working condition.

[0046] Referring to Figure 1 As shown, according to some embodiments of the present application, the second cold pipe 2 is provided with a second control valve 9. Similarly, by providing the second control valve 9 on the second cold pipe 2, the second cold pipe 2 can be controlled to be turned on or turned off. When the marine natural circulation cooling system is not in use, the second cold pipe 2 can be closed by the second control valve 9 to prevent seawater from entering the second cold pipe 2. When the offshore floating platform is shut down, the natural circulation cooling system is put into use, at which time the second control valve 9 can be opened to guide the seawater with a lower temperature into the second cold pipe 2. In addition, by adjusting the opening of the second control valve 9, the inflow of seawater can also be adjusted to adapt to the current working condition.

[0047] Referring to Figure 1 As shown, according to some embodiments of the present application, the heat pipe 3 is provided with a third control valve 10. By providing the third control valve 10 on the heat pipe 3, the heat pipe 3 can be controlled to be turned on or turned off. When the marine natural circulation cooling system is not in use, the heat pipe 3 can be closed by the third control valve 10 to prevent seawater from entering the heat pipe 3. When the offshore floating platform is shut down, the natural circulation cooling system is put into use, at which time the third control valve 10 can be opened to guide the seawater with a higher temperature out.

[0048] Specifically, the first control valve 8, the second control valve 9 and the third control valve 10 can all be electromagnetic valves, which are in communication connection with the control unit and can be remotely controlled by the control unit.

[0049] The marine natural circulation cooling system provided by the present application will be described below, and the marine natural circulation cooling system described below can be mutually corresponding with the cooling circulation loop described above.

[0050] The marine natural circulation cooling system provided by the embodiments of the present application comprises a reactor and the cooling circulation loop as described in any one of the above embodiments, and the reactor is connected with the heat exchanger 4.

[0051] The marine natural circulation cooling system provided by the present application can also inhibit the system pressure pulsation and flow oscillation problems caused by the severe boiling of the heat exchanger 4 in the system and strengthen the heat exchange effect of the heat exchanger 4 due to the adoption of the above cooling circulation loop, and solves the defect that the way of increasing the bubble lifting device in the ascending section of the natural circulation system in the prior art cannot greatly enhance the natural circulation heat transfer capacity.

[0052] It should be pointed out finally that the above embodiments are only used to illustrate the technical solutions of the present application, but not to limit the same; and although the present application has been described in detail with reference to the foregoing embodiments, it should be appreciated by those skilled in the art that the technical solutions recorded in the foregoing embodiments can be modified, or some technical features thereof can be replaced equivalently; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A cooling circulation loop, characterized in that, include: First cold pipe, second cold pipe, heat pipe, heat exchanger and storage chamber; The storage chamber is equipped with phase change thermal storage particles. The density of the phase change thermal storage particles is less than that of seawater. The phase change thermal storage particles can change from a solid phase to a liquid phase at a set temperature. The heat exchanger is provided with a riser pipe. One end of the first cold pipe is connected to the inlet end of the riser pipe, and the other end of the first cold pipe is used to connect to hot hydrazine seawater. One end of the second cold pipe is connected to the storage chamber, and the other end of the second cold pipe is used to connect to hot hydrazine seawater. The storage chamber is provided with a discharge port, which is connected to the inlet end of the riser pipe so as to send the phase change heat storage particles in the storage chamber into the riser pipe through hot hydrazine seawater. One end of the heat pipe is connected to the outlet end of the riser pipe, and the other end of the heat pipe is used to connect to hot hydrazine seawater. The first cold pipe is located above the second cold pipe, and the riser pipe is located above the storage chamber; The discharge port is located on the side of the storage chamber facing the riser pipe, and the inner diameter of the discharge port gradually decreases to form a constricted shape in order to guide the phase change thermal storage particles.

2. The cooling circulation loop according to claim 1, characterized in that, The ratio of the particle size of the phase change thermal storage particles to the inner diameter of the riser pipe is 0.01 to 0.

1.

3. The cooling circulation loop according to claim 1, characterized in that, The phase change thermal storage particles include at least one of aliphatic compounds.

4. The cooling circulation loop according to any one of claims 1 to 3, characterized in that, The first control valve is provided on the first cold pipe.

5. The cooling circulation loop according to any one of claims 1 to 3, characterized in that, The second cooling pipe is equipped with a second control valve.

6. The cooling circulation loop according to any one of claims 1 to 3, characterized in that, The heat pipe is equipped with a third control valve.

7. The cooling circulation loop according to any one of claims 1 to 3, characterized in that, The heat exchanger is a partition wall type heat exchanger.

8. A marine natural circulation cooling system, characterized in that, It includes a reactor and a cooling circulation loop as described in any one of claims 1 to 7, wherein the reactor is connected to the heat exchanger.

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