Cooling circulation loop and marine natural circulation cooling system

Abstract

The invention relates to the technical field of reactor cooling, and provides a cooling circulation loop and a marine natural circulation cooling system. The cooling circulation loop comprises a first cooling pipe, a second cooling pipe, a heat pipe, a heat exchanger and a storage chamber; phase change heat storage particles with the density smaller than that of seawater are arranged in the material storage chamber; the heat exchanger is provided with an ascending pipe, one end of the first cooling pipe is connected with the inlet end of the ascending pipe, the other end of the first cooling pipe is used for being connected with hot hydrazine seawater, one end of the second cooling pipe is connected with the storage chamber, the other end of the second cooling pipe is used for being connected with the hot hydrazine seawater, and the storage chamber is provided with a discharging port which is connected with the inlet end of the ascending pipe. One end of the heat pipe is connected with the outlet end of the ascending pipe, and the other end of the heat pipe is used for being connected with hot hydrazine seawater. According to the cooling circulation loop and the marine natural circulation cooling system, the defect that in the prior art, the natural circulation heat transfer capacity cannot be greatly enhanced in the mode that a bubble lifting device is additionally arranged in the ascending section of a natural circulation system is overcome.

Description

Technical Field

[0001] The invention relates to the technical field of reactor cooling, and in particular to a cooling circulation loop and a marine natural circulation cooling system. Background Art

[0002] After the reactor is shut down, the core will continue to generate residual heat. If it cannot be discharged in time, it may cause the fuel rod cladding to melt, resulting in the leakage of radioactive materials, which in turn threatens the safety of personnel and equipment. In order to solve the problem of residual heat extraction after the reactor is shut down, the system is designed with a natural circulation cooling system connected to the hot hydrazine seawater. The fluid density difference is used to drive the circulation of the coolant and transfer the residual heat to the hot hydrazine seawater. However, due to the limited system space, the height difference of the cold and hot sources of the natural circulation cooling system is insufficient, resulting in its 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 violent boiling may occur in the loop, which will cause large pressure pulsations and flow oscillations, which will pose a threat to the safety of the core and affect the stability of the offshore floating platform.

[0003] In order to solve the problem of insufficient heat transfer capacity of the system caused by the effective height difference of cold and hot sources in the natural circulation system, the common method is to add a bubble lifting device in the rising section of the natural circulation system, inject bubbles into the rising pipe to reduce the fluid density in the pipe, so as to increase the density difference between the cold and hot pipes in the system and enhance the heat transfer capacity of the natural circulation. However, due to the small space in the system, the height of the rising section of the natural circulation system is very small, which makes this method have little effect 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 surface, causing heat transfer deterioration and endangering the safety of the system. Summary of the invention

[0004] The present invention provides a cooling circulation loop and a marine natural circulation cooling system, which are used to solve the defect in the prior art that the method of adding a bubble lifting device in the rising section of the natural circulation system cannot significantly enhance the natural circulation heat transfer capacity.

[0005] One aspect of the present invention 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] Phase-change heat storage particles are arranged in the storage chamber. The density of the phase-change heat storage particles is lower than that of seawater. The phase-change heat storage particles can change from a solid state to a liquid state at a set temperature.

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

[0008] According to the cooling circulation loop provided by the present invention, the first cooling pipe is located above the second cooling pipe, and the rising pipe is located above the storage chamber.

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

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

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

[0012] According to the cooling circulation loop provided by the present invention, a first control valve is provided on the first cooling pipe.

[0013] According to the cooling circulation loop provided by the present invention, a second control valve is provided on the second cooling pipe.

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

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

[0016] Another aspect of the present invention provides a marine natural circulation cooling system, comprising a reactor and a cooling circulation loop as described in any one of the above items, wherein the reactor is connected to the heat exchanger.

[0017] The principles of the cooling circulation loop and the marine natural circulation cooling system provided by the present invention are as follows.

[0018] When the offshore floating platform is shut down, the marine natural circulation cooling system is put into use, and the heat of the reactor is transferred to the heat exchanger. Under the heating effect of the hot side of the heat exchanger, the temperature of the fluid in the riser gradually increases and the density gradually decreases. Under the driving force of the density difference between the seawater and the fluid in the riser, the hot hydrazine seawater in the ocean passes through the first cold pipe, the riser, and the heat pipe, and finally returns to the seawater to form a cooling cycle. At the same time, when the natural circulation cooling system is put into use at the initial shutdown stage, the phase change heat storage particles in the storage chamber enter the riser of the heat exchanger under the driving effect of seawater. Since the density of the injected phase change heat storage particles is less than that of seawater, the phase change heat storage particles flow into the riser under the action of buoyancy and reduce the density of the mixed fluid in the heat exchanger. Due to the increase in the density difference between the heat pipe of the heat exchanger and the seawater, the driving force of the cooling cycle loop is enhanced, and the natural circulation flow rate is increased, thereby indirectly weakening the boiling phenomenon of the fluid in the riser of the heat exchanger, thereby suppressing the system pressure pulsation and flow oscillation problems caused by the violent boiling of the heat exchanger in the system. And because 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 cause a disturbance to the heat transfer boundary layer near the wall of the heat exchanger riser, thereby enhancing the heat transfer effect of the heat exchanger and will not cause heat transfer deterioration like bubbles attached to the heat transfer wall.

[0019] The cooling circulation loop and marine natural circulation cooling system provided by the present invention, by providing a storage chamber and phase change heat storage particles in the storage chamber, can suppress the system pressure pulsation and flow oscillation problems caused by the violent boiling of the heat exchanger in the system, and enhance the heat exchange effect of the heat exchanger, thereby solving the defect in the prior art that the method of adding a bubble lifting device in the rising section of the natural circulation system cannot significantly enhance the natural circulation heat transfer capacity.

[0020] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0022] Figure 1 Schematic diagram of a cooling cycle provided by an embodiment of the present invention.

[0023] Reference numerals: 1. First cold pipe; 2. Second cold pipe; 3. Hot pipe; 4. Heat exchanger; 5. Storage chamber; 6. Phase change heat storage particles; 7. Rising pipe; 8. First control valve; 9. Second control valve; 10. Third control valve. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] In the description of the embodiments of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limitations on the embodiments of the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0026] In the description of the embodiments of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances.

[0027] In the embodiments of the present invention, unless otherwise clearly specified and limited, the first feature being "above" or "below" the second feature may mean 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 being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0028] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiment of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0029] Combine the following Figure 1 The cooling circulation loop and the marine natural circulation cooling system provided by the embodiments of the present invention are described.

[0030] See also Figure 1 As shown, the cooling circulation loop provided by the embodiment of the present invention includes: a first cold pipe 1, a second cold pipe 2, a heat pipe 3, a heat exchanger 4 and a storage chamber 5.

[0031] Phase-change heat storage particles 6 are arranged in the storage chamber 5. The density of the phase-change heat storage particles 6 is lower than that of seawater. The phase-change heat storage particles 6 can change from a solid state to a liquid state at a set temperature.

[0032] The heat exchanger 4 is provided with a riser 7, which is used to exchange heat with the hot side of the heat exchanger. One end of the first cold pipe 1 is connected to the inlet end of the riser 7, and the other end of the first cold pipe 1 is used to be connected to the hot hydrazine seawater. One end of the second cold pipe 2 is connected to the storage chamber 5, and the other end of the second cold pipe 2 is used to be connected to the hot hydrazine seawater. The storage chamber 5 is provided with a discharge port, which is connected to the inlet end of the riser 7 to deliver 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 to the outlet end of the riser 7, and the other end of the heat pipe 3 is used to be connected to the hot hydrazine seawater.

[0033] The cooling circulation loop and marine natural circulation cooling system provided by the present invention, by providing a storage chamber 5 and providing phase change heat storage particles 6 in the storage chamber 5, can suppress the system pressure pulsation and flow oscillation problems caused by the violent boiling of the heat exchanger 4 in the system, and enhance the heat exchange effect of the heat exchanger 4, thereby solving the defect in the prior art that the method of adding a bubble lifting device in the rising section of the natural circulation system cannot significantly enhance the natural circulation heat transfer capacity.

[0034] Specifically, when the marine floating platform is shut down, the ship's natural circulation cooling system is put into use, and the heat of the reactor is transferred to the heat exchanger 4. Under the heating action of the hot side of the heat exchanger 4, the temperature of the fluid in the riser 7 gradually increases and the density gradually decreases. Under the driving force of the density difference between the seawater and the fluid in the riser 7, the hot hydrazine seawater in the ocean passes through the first cold pipe 1, the riser 7, and the heat pipe 3, and finally returns to the seawater to form a cooling cycle. At the same time, when the natural circulation cooling system is put into use at the initial 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 seawater. Since the density of the injected phase change heat storage particles 6 is less than that of 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 exchange tube 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 rate is increased, thereby indirectly weakening the boiling phenomenon of the fluid in the riser 7 of the heat exchanger 4, thereby suppressing the system pressure pulsation and flow oscillation problems caused by the violent boiling of the heat exchanger 4 in the system. And because the injected phase change heat storage particles 6 are fine solid phase particles, before the solid phase heat storage material is heated and melted, the solid phase heat storage material particles can cause a disturbance to the heat transfer boundary layer near the wall of the riser 7 of the heat exchanger 4, thereby enhancing the heat exchange effect of the heat exchanger 4, and will not cause heat transfer deterioration like bubbles attached to the heat transfer wall.

[0035] The heat exchanger 4 is a partition-type 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. The riser 7 side finally transfers the heat to the hot hydrazine seawater, thereby realizing reactor cooling. The partition-type heat exchanger 4 includes a shell-side heat exchanger 4, a plate heat exchanger 4, a shell and tube heat exchanger 4, etc.

[0036] The phase-change heat storage particles 6 may be at least one of aliphatic compounds (such as paraffin), that is, the phase-change heat storage particles 6 may be any one of aliphatic compounds or a mixture of any multiple of them.

[0037] Preferably, in this embodiment, the phase change heat storage particles 6 are paraffin particles. After the paraffin (the main component is normal alkanes, and the melting point is usually between 40°C and 60°C) enters the riser 7 of the heat exchanger 4, the seawater temperature in the riser 7 is greater than the melting point of the paraffin, which can cause it to melt and mix with the seawater to form a mixed fluid with a density lower than that of seawater.

[0038] See also Figure 1As shown, according to some embodiments of the present invention, the first cold pipe 1 is located above the second cold pipe 2, and the riser 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 arranging the first cold pipe 1 above the second cold pipe 2 and arranging the riser 7 above the storage chamber 5, the phase-change heat storage particles 6 in the storage chamber 5 can be driven by seawater to automatically rise into the riser 7 of the heat exchanger 4 without the need to set up other driving devices.

[0039] 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. 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.

[0040] In a specific implementation, a feeding pipe connected to the storage chamber 5 can be provided. When the phase change heat storage particles 6 in the storage chamber 5 are used up, the storage chamber 5 can be fed with materials by means of pressurization or the like.

[0041] See also Figure 1 As shown, according to some embodiments of the present invention, the discharge port is located on the side of the storage chamber 5 facing the riser 7, and the inner diameter of the discharge port gradually decreases to form a constriction shape to guide the phase-change heat storage particles 6. By setting the discharge port to a constriction shape with a gradually decreasing inner diameter, the phase-change heat storage particles 6 in the storage chamber 5 can be gathered, so as to facilitate their introduction into the riser 7 of the heat exchanger 4.

[0042] See also Figure 1 As shown, according to some embodiments of the present invention, the ratio of the particle size of the phase-change heat storage particles 6 to the inner diameter of the riser 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 7 within the range of 0.01 to 0.1, the injected phase-change heat storage particles can not only enhance the heat exchange effect in the heat exchange tube, but also avoid blocking the flow channel.

[0043] For example, the inner diameter of the riser 7 is 20 mm, and the particle size of the phase-change heat storage particles 6 is 0.2 mm to 2 mm.

[0044] See also Figure 1 As shown, according to some embodiments of the present invention, a first control valve 8 is provided on the first cold pipe 1. By providing the first control valve 8 on the first cold pipe 1, the conduction or shutoff of the first cold pipe 1 can be controlled. When the marine natural circulation cooling system is not in 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. When the marine floating platform is shut down, the natural circulation cooling system is put into use. At this 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 of the first control valve 8, the water inflow flow of seawater can also be adjusted to adapt it to the current working conditions.

[0045] See also Figure 1 As shown, according to some embodiments of the present invention, a second control valve 9 is provided on the second cold pipe 2. Similarly, by providing the second control valve 9 on the second cold pipe 2, the conduction or shutoff of the second cold pipe 2 can be controlled. 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 marine floating platform is shut down, the natural circulation cooling system is put into use. At this time, the second control valve 9 can be opened to introduce seawater with a lower temperature into the second cold pipe 2. In addition, by adjusting the opening of the second control valve 9, the water inflow flow of seawater can also be adjusted to adapt it to the current working conditions.

[0046] See also Figure 1 As shown, according to some embodiments of the present invention, a third control valve 10 is provided on the heat pipe 3. By providing the third control valve 10 on the heat pipe 3, the conduction or shutoff of the heat pipe 3 can be controlled. When the marine natural circulation cooling system is not put into 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 marine floating platform is shut down, the natural circulation cooling system is put into use. At this time, the third control valve 10 can be opened to export the seawater with increased temperature.

[0047] Specifically, the first control valve 8, the second control valve 9 and the third control valve 10 can all be solenoid valves, which are communicatively connected with the control unit and can be remotely controlled by the control unit.

[0048] The marine natural circulation cooling system provided by the present invention is described below. The marine natural circulation cooling system described below and the cooling circulation loop described above can be referred to each other.

[0049] The marine natural circulation cooling system provided in an embodiment of the present invention comprises a reactor and a cooling circulation loop as described in any one of the above embodiments, and the reactor is connected to a heat exchanger 4 .

[0050] The marine natural circulation cooling system provided by the present invention adopts the above-mentioned cooling circulation loop, and therefore can also suppress the system pressure pulsation and flow oscillation problems caused by the violent boiling of the heat exchanger 4 in the system, and enhance the heat exchange effect of the heat exchanger 4, thereby solving the defect in the prior art that the method of adding a bubble lifting device in the rising section of the natural circulation system cannot significantly enhance the natural circulation heat transfer capacity.

[0051] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A cooling cycle, characterized in that: include: A first cold pipe, a second cold pipe, a hot pipe, a heat exchanger and a storage chamber; Phase-change heat storage particles are arranged in the storage chamber, 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; The heat exchanger is provided with a riser, one end of the first cold pipe is connected to the inlet end of the riser, the other end of the first cold pipe is used to be connected to hot hydrazine seawater, one end of the second cold pipe is connected to the storage chamber, the other end of the second cold pipe is used to be connected to hot hydrazine seawater, the storage chamber is provided with a discharge port, the discharge port is connected to the inlet end of the riser, so as to deliver the phase change heat storage particles in the storage chamber into the riser through hot hydrazine seawater, one end of the heat pipe is connected to the outlet end of the riser, and the other end of the heat pipe is used to be connected to hot hydrazine seawater.

2. The cooling circuit according to claim 1, characterized in that: The first cooling pipe is located above the second cooling pipe, and the rising pipe is located above the storage chamber.

3. The cooling circuit according to claim 2, characterized in that: The discharge port is located on a side of the storage chamber facing the riser, and the inner diameter of the discharge port gradually decreases to form a constricted shape to guide the phase-change heat storage particles.

4. The cooling circuit according to claim 1, characterized in that: The ratio of the particle size of the phase-change heat storage particles to the inner diameter of the riser is 0.01 to 0.

1.

5. The cooling cycle according to claim 1, characterized in that: The phase-change heat storage particles include at least one aliphatic compound.

6. The cooling cycle according to any one of claims 1 to 5, characterized in that: The first cooling pipe is provided with a first control valve.

7. The cooling cycle according to any one of claims 1 to 5, characterized in that: The second cooling pipe is provided with a second control valve.

8. The cooling cycle according to any one of claims 1 to 5, characterized in that: The heat pipe is provided with a third control valve.

9. The cooling cycle according to any one of claims 1 to 5, characterized in that: The heat exchanger is a partition type heat exchanger.

10. A marine natural circulation cooling system, characterized in that: The invention comprises a reactor and a cooling circulation loop as claimed in any one of claims 1 to 9, wherein the reactor is connected to the heat exchanger.

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