KR102008299B1 - Passive cooling system of nuclear power plant using solid and liquid phase change material - Google Patents

Abstract

The present invention relates to a passive cooling system of a nuclear power plant using solid and liquid phase change materials, comprising: a pipe which includes an insertion unit communicating with the inside of a cooling target and a discharge unit communicating with the outside of the cooling target, and through which a coolant is accommodated in the inside and the outside to be transferred; an inner heat exchanger connected to the pipe provided on the inside of the cooling target; and an outer heat exchanger connected to the pipe provided on the outside of the cooling target. The coolant, with a solvent accommodated in the pipe, is inserted into the cooling target through the insertion unit, is discharged to the outside of the cooling target through the discharge unit, and is circulated to the inside and the outside of the cooling target along the pipe, thereby being phase conversion materials (Na(CH_3COO)3H_2O) determined by a phase change material loop (PCM LOOP) discharging heat in the cooling target to the outside.

Description

Passive COOLING SYSTEM OF NUCLEAR POWER PLANT USING SOLID AND LIQUID PHASE CHANGE MATERIAL}

The present invention is to cool the atmosphere or fluid inside the target such as buildings (containment building, spent fuel storage tank, etc.) and equipment (reactor coolant system, passive auxiliary water supply, passive auxiliary water supply tank, etc.) that require cooling among nuclear power plants. The present invention relates to a passive cooling system for the safety of nuclear power plants.

More specifically, a large amount of energy is generated during an accident / accident of a nuclear power plant, and a test device (such as a building or a device that needs to be cooled for the safety of the nuclear power plant) is operated without a separate operator action or operation of equipment that requires on-site / external power. The phase change material (Na (CH ₃ COO) 3H ₂ O) determined by PCM LOOP, (PCM: Phase Change Material) is used to passively reduce the pressure and temperature rise, thereby maintaining the integrity of the cooling target and maintaining the integrity of the system. The present invention relates to a nuclear power plant passive cooling system using solid and liquid phase change materials that can secure the safety of a nuclear power plant by allowing the fluid to continuously function.

In terms of safety, the reactor coolant system serves to cool the core containing the fuel and keep the core in a safe state.

On the other hand, if core cooling is not performed smoothly in case of nuclear power plant accidents and accidents, the cooling function of the core and reactor coolant systems is very important for nuclear power plant safety since nuclear fuel cladding may be exposed and the core may be expanded to serious accidents.

Therefore, the system for cooling the core and reactor coolant systems indirectly cools the core and reactor coolant systems by injecting auxiliary water to the secondary side of the steam generator and the safety injection / stop cooling system that performs cooling by directly injecting coolant into the reactor coolant system. A supplementary water supply system is provided.

The containment building is also located inside the reactor core, reactor coolant system and safety-related systems / equipment and consists of reinforced concrete outer walls combined with a cylinder and a round dome.

In this context, the term 'containment' protects the reactor core, reactor coolant system and safety-related systems / equipment from external shocks, and prevents the leakage or leakage of radioactive material from inside the containment building in case of a nuclear power plant accident / incident. It is used in the sense of preventing, and is the last defense against the leakage of radioactive material in the event of an accident / accident at a nuclear power plant.

Such containment may perform the above functions, but if a nuclear accident exposes a core accident to melt the core, and if the containment integrity is impaired, a large amount of radioactive material may leak out of the containment, causing severe damage.

Therefore, securing the soundness of containment building is very important for the safety of nuclear power plants.

Currently, nuclear power plants are equipped with safety-related reactor coolant system pressure measurement equipment to prevent core melting due to exposure of reactor cores for a short period of time after accidents / incidents. Through the automatic operation of the interlocking safety injection system, boric acid water flows into the reactor coolant system, and the containment sprinkling system interlocked with the safety-related containment pressure measuring device automatically operates to condense the steam inside the containment building to condense the pressure inside the containment building. The containment temperature should be reduced to below the design value to ensure the integrity of the containment building, and then the stop cooling system and the containment sprinkling system should be continuously operated to ensure core melt and containment building integrity.

At this time, if the amount of boric acid inflow of the reactor coolant system is sufficient to cause natural circulation, the operation of the auxiliary water supply system can remove heat from the core and reactor coolant system through the steam generator. For this purpose, steam generator level monitoring should also be maintained.

However, if the stock of the reactor coolant system is not large enough to cause natural circulation in the system, or if the water level monitoring function of the steam generator is lost, or if the water in the auxiliary feed tank is depleted, the steam generator can perform heat removal. There is no limit.

In addition, the safety injection / stop cooling system and the containment water system contain automatic pumps, automatic valves, and active devices that operate in conjunction with safety-related measuring devices.If these devices fail, the main control room It is designed to allow manual operation by the operator's action (hand position operation).

Therefore, power supply is essential for the operation of these systems, and the heat generated inside the containment is transferred to the device cooling system through the stationary cooling / spray heat exchanger, and the transferred heat is transferred to the device cooling seawater system through the device cooling water heat exchanger. The transferred heat inside the containment building is discharged to the sea as the final source of heat removal through the system cooling seawater system.

In addition, the spent fuel stored in the nuclear power plant's storage is continuously generating decay heat of nuclear fuel products. Cooling is performed through heat exchangers and pumps, and the decay heat transferred through the heat exchangers is the final source of heat removal. Is released.

However, when a tsunami, such as Fukushima, causes the function of the system cooling seawater system to be lost, or the equipment cooling heat exchanger building or the like causes an accident such as an aircraft collision, the function of the system cooling system is lost. There is a problem that the cooling function cannot be performed because the heat cannot be discharged through the stationary cooling / spray heat exchanger and the device cooling water heat exchanger, and the decay heat of the nuclear fuel reservoir cannot be discharged to the sea as the final heat removal source through the reservoir cooling heat exchanger. .

In addition, since the systems include a plurality of active devices that require power supply, there is a problem in that the cooling function of the containment building cannot be performed even when an accident such as an alienated power loss or a complete power loss occurs.

For example, the Fukushima nuclear power plant accident is a complete power loss accident with the loss of the final heat source.

As an example for cooling a containment building, Korean Patent Publication No. 10-1517449 discloses a liquid metal filling system for cooling an outer wall of a reactor vessel.

1 is a schematic view showing a configuration of a liquid metal filling system for cooling a conventional reactor vessel outer wall, the configuration of which is a reactor vessel containing a core melt; A first reactor cavity 110 disposed in a shape spaced apart from the outer wall of the reactor vessel by a predetermined interval and filled with a liquid metal 111 circulated and supplied to the outer wall; A second reactor cavity (120) disposed in the form of being surrounded by a predetermined interval from the partition wall of the first reactor cavity (110) and filled with coolant (121) circulated and supplied in contact with the partition wall; And one side is disposed inside the first reactor cavity 110 and the other side is disposed inside the second reactor cavity 120 while being inserted through the partition wall of the first reactor cavity 110, and one side and the other side are disposed. Including a closed circuit structure in communication with the first heat pipe 130 to transfer the heat of the liquid metal 111 is heated to the cooling water 121; including, the first heat pipe 130 is the first reactor cavity ( 110 and the portion disposed inside the second reactor cavity 120 is bent a plurality of times or a plurality of protrusions is characterized in that formed.

The liquid metal filling system for cooling the outer wall of the conventional reactor vessel uses a coolant made of the liquid metal 111 for cooling the outer wall of the reactor vessel, thereby achieving thermal safety, and further, the inside and the first reactor cavity 110. The heated heat of the liquid metal 111 filled in the first reactor cavity 110 by the first heat pipe 130 disposed so as to span the two reactor cavity 120 of the second reactor cavity 120. By transferring to the added cooling water 121, the heated heat of the reactor vessel is cooled.

However, the prior art generally includes a first reactor cavity 110 and a first reactor cavity 110 having a large volume so that the reactor vessel can be accommodated outside of the reactor vessel having a two or three floor size of a building. Since the second reactor cavity 120 having a large volume to be provided, it takes up a large volume in the installation of the containment building, there is a problem that the construction cost is increased.

In addition, the liquid metal reservoir 112 is installed to be located above the reactor vessel, so that the liquid metal 111 is provided to the inside of the first reactor cavity 110 by gravity, but as described above, In order to install the liquid metal storage tank 112 higher than the reactor vessel having a two- and three-layer size of a building, it takes up a large volume, and there is a problem in that installation cost is not easy to install.

In addition, by adopting the filling method using gravity, it is positive that it can be operated in the event of power plant loss accident, but the liquid metal 112 stored in the liquid metal storage tank 112 is in a liquid state (about 600 ℃ or more) In order to maintain the liquid metal reservoir 112 is provided with a separate heating device, by requiring a separate power in order to maintain the continuous operation of the heating device, there is a problem that a separate operator must be always waiting.

In addition, a device is needed to prevent the heating of the fluid inside the reactor coolant system and the water introduced into the containment system during the accident / accident of the nuclear power plant. There is a problem in that the containment temperature reaches 600 ° C. and thus the containment building integrity cannot be guaranteed.

Registered Patent Publication No. 10-1517449 (2015.04.28.) Publication No. 10-2014-0000411 (January 3, 2014)

The present invention has been made to solve the above problems, the problem to be solved in the present invention is a power plant that can be caused by the temperature and pressure rise inside the building, as a lot of energy generated during the nuclear power plant accident / accident is released. In order to prevent the malfunction of the safety system and the threat of building health in advance, the test apparatus (without the use of active devices such as a stop cooling / spray system that requires external operator action or an external power source) The phase change material (Na (CH ₃ COO) 3H ₂ O) determined by 100) effectively reduces the pressure and temperature rise of the cooling target to maintain the integrity of the cooling target and to cool the fluid in the system. By using the solid and liquid phase conversion materials to ensure the safety of nuclear power plants To provide a passive cooling system for nuclear power plants.

In order to solve the above problems, the nuclear power plant passive cooling system using a solid, liquid phase conversion material according to the present invention includes an inlet communicated to the inside of the cooling target and an outlet communicated to the outside, the coolant is accommodated inside / outside Pipe that is transported; An internal heat exchanger connected to a pipe provided inside the cooling target; And an external heat exchanger connected to a pipe provided outside the object to be cooled, wherein the coolant is introduced into the object to be cooled through the inlet and the solvent contained in the pipe, and is discharged to the outside of the object to be cooled through the outlet. By being circulated to the inside and outside of the cooling target, the solid is characterized in that the phase conversion material (Na (CH ₃ COO) 3 H ₂ O) determined by the test device (PCM LOOP) for discharging the heat inside the cooling target to the outside. In order to solve the technical problem, a passive cooling system for nuclear power plants using liquid phase conversion materials is provided.

The present invention has a significant effect of passively removing heat inside a cooling target by using a phase change material (Na (CH ₃ COO) 3 H ₂ O).

In addition, the present invention has a remarkable effect of using the external atmosphere of the cooling target as the final heat removal source, so that no additional operator action such as supply of electricity or cooling water is required, that is, cooling without external power is not required. Doing.

In addition, the present invention is a natural convection circulation due to the significant density difference between the phases generated when the fluid of the cooling system containing a phase change material (Na (CH ₃ COO) 3 H ₂ O) phase conversion in the internal / external temperature range of the cooling target By doing so, it has a remarkable effect that cooling can be performed in the long term without time limitation.

In addition, the present invention uses the phase change material (Na (CH ₃ COO) 3 H ₂ O) determined by the test apparatus 100 to absorb more heat in the cooling target by high heat of fusion (264 J / g). It can be operated only when an accident occurs due to the melting temperature (58.4 ℃) higher than the normal operation temperature and lower than the accident temperature, and 78.2g / 100ml (water) at 0 ℃, and 138.8 / at 50 ℃ Due to the high solubility of 100 ml (water), many phase change materials (Na (CH ₃ COO) 3H ₂ O) are stably dissolved in water to improve fluidity due to natural convection, and the high density of 1.45kg / dm ³ It can absorb a lot of heat compared to the same volume, and it has a remarkable effect of improving natural convection enhancement by high density difference (13.28%) during phase conversion.

1 is a schematic view showing the configuration of a liquid metal filling system for cooling the outer wall of a conventional reactor vessel.
2 is a schematic diagram of a nuclear power plant passive cooling system using a solid, liquid phase change material according to the present invention.
3 and 4 are views for explaining the principle of the phase conversion material (Na (CH ₃ COO) 3 H ₂ O) in the nuclear power plant passive cooling system using a solid, liquid phase conversion material according to the present invention.
5 is a schematic view showing a test apparatus in a nuclear power plant passive cooling system using a solid, liquid phase conversion material according to the present invention.
6 is a view showing a heating unit of the test apparatus in the nuclear power plant passive cooling system using a solid, liquid phase conversion material according to the present invention.
7 is a view showing the cooling unit of the test apparatus in the nuclear power plant passive cooling system using a solid, liquid phase conversion material according to the present invention.
8 is a view showing an example in which an elastic member is provided in a test apparatus in a nuclear power plant passive cooling system using a solid, liquid phase change material according to the present invention.
Figure 9 shows the temperature distribution results and velocity distribution results of the phase conversion material (Na (CH ₃ COO) 3 H ₂ O) and water using a test apparatus in the nuclear power plant passive cooling system using a solid, liquid phase conversion material according to the present invention Drawing.
10 is a view showing an example in which heat increases due to a temperature increase inside a cooling target in a nuclear power plant passive cooling system using a solid or liquid phase change material according to the present invention.
FIG. 11 is a view illustrating an example in which a phase change material in a solid state absorbs heat inside a cooling target in a liquid state and is discharged to the outside in a nuclear power plant passive cooling system using a solid or liquid phase change material according to the present invention.

Advantages and features of the embodiments of the present invention, and methods of achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be embodied in various different forms, and the present embodiments merely make the disclosure of the present invention complete and common knowledge in the technical field to which the present invention belongs. It is provided to fully inform the person having the scope of the invention, which is defined only by the scope of the claims. Like reference numerals refer to like elements throughout.

In describing the embodiments of the present invention, if it is determined that a detailed description of a known function or configuration may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted. Terms and words used in the present specification and claims are terms defined in consideration of functions in the embodiments of the present invention, and should not be construed as being limited to ordinary or dictionary meanings. It should be interpreted as meaning and concept corresponding to the technical idea of the present invention based on the principle that the concept of the term can be properly defined in order to explain in the best way.

Therefore, the embodiments described in the specification and the drawings shown in the drawings are only the most preferred embodiments of the present invention and do not represent all of the technical idea of the present invention, various equivalents that may be substituted for them at the time of the present application It should be understood that there may be variations and examples.

Before describing the present invention with reference to the drawings, matters that are not necessary to reveal the gist of the present invention, that is, well-known configurations that can be obviously added by those skilled in the art will not be shown or described in detail. Make sure you didn't.

First, before describing various embodiments of the present invention with reference to the accompanying drawings, the orientation of the components (eg, "before", "after", "left") described in the following detailed description or shown in the drawings. , "Right", "up", "down", "up", "bottom", "lateral", "species", "front", "back", "one side", "other side", "inside" and " It does not indicate or mean simply having a specific direction with respect to terms such as " outside ") and the like, and descriptions of such directions are made to facilitate explanations between the components with reference to the accompanying drawings.

The passive cooling system for nuclear power plants using solid and liquid phase change materials according to the present invention is a measure of monitoring the state of a power plant which may be caused by a rise in temperature and pressure inside a building as a large amount of energy generated during an accident / accident of a nuclear power plant is released. In order to prevent the malfunction of the equipment and safety system and the threat of building health in advance, the image determined by the test apparatus 100 without the use of active devices such as a stop cooling / spray system requiring additional operator action or external power. By using a converting substance (Na (CH ₃ COO) 3H ₂ O), the pressure and temperature rise of the cooling target 10 are effectively reduced by passively maintaining the integrity of the cooling target 10, and the fluid in the system is cooled to Passive cooling system using a solid and liquid phase change material that can ensure the safety of the nuclear power plant as the system can be guaranteed continuously. It relates.

Hereinafter, with reference to the accompanying drawings will be described in detail the nuclear power plant passive cooling system using a solid, liquid phase conversion material according to the present invention.

Figure 2 is a schematic diagram of a nuclear power plant passive cooling system using a solid, liquid phase conversion material according to the present invention, Figures 3 and 4 is a phase conversion material in a nuclear power plant passive cooling system using a solid, liquid phase conversion material ( Figure 5 is a view for explaining the principle of Na (CH ₃ COO) 3H ₂ O), Figure 5 is a schematic diagram showing a test apparatus in a nuclear power plant passive cooling system using a solid, liquid phase conversion material according to the present invention, Figure 6 FIG. 7 is a view illustrating a heating unit of a test apparatus in a nuclear power plant passive cooling system using a solid and liquid phase change material according to the present invention, and FIG. 7 is a cooling unit of the test apparatus in a nuclear power plant passive cooling system using a solid and liquid phase change material according to the present invention. a view showing, Fig. 8 is a view showing an example in which the elastic member is provided in the testing apparatus in the nuclear power plant driven cooling system using a solid-liquid phase change materials according to the invention, Figure 9 is present to In using a test apparatus in nuclear power driven cooling system using a solid-liquid phase change materials according to the phase-change material _{(Na (CH 3 COO) 3H} 2 O) and a chart showing the temperature of the water distribution results and the velocity distribution results, 10 Is a view showing an example in which the heat is increased in accordance with the temperature rise inside the cooling target in the nuclear power plant passive cooling system using a solid, liquid phase conversion material according to the present invention, Figure 11 is a solid, liquid phase conversion material according to the present invention In the nuclear power plant passive cooling system used, the solid phase change material absorbs heat inside the cooling target in a liquid state and shows an example of discharging it to the outside.

First, in the present specification, the cooling target 10 refers to a containment building, a nuclear fuel storage tank, a reactor coolant system, a safety system of a nuclear power plant, a passive auxiliary water supply or a passive auxiliary water supply tank, and the like, which are provided in a nuclear power plant. In planning, it means a building or a device that requires a cooling function.

Nuclear power plant passive cooling system using a solid, liquid phase conversion material according to the present invention by discharging the energy flowing into the cooling target 10 when the nuclear power plant accident / accident occurs to the outside by increasing the temperature and pressure inside the cooling target 10 In order to prevent the malfunction of the measuring system and the safety system and the threat of the health of the building which may be caused, the pipe 20, the internal heat exchanger 30 and the external heat exchanger 40 are included. It is configured by.

As shown in FIG. 2, the pipe 20 includes an inlet part 21 communicating with the inside of the cooling target 10 and an outlet part 22 communicating with the outside, and the outlet part 21 is discharged from the inlet part 21. A portion of the pipe 20 is provided inside the cooling target 10 through the unit 22, and the remaining portion is provided outside the cooling target 10, so that the pipe 20 is inside the cooling target 10. It is provided to communicate with the outside.

As illustrated in the accompanying drawings, the pipe 20 is provided to connect the internal heat exchanger 30 provided inside the cooling target 10 and the external heat exchanger 40 provided outside.

At this time, the pipe 20 is excellent in corrosion resistance, does not rust well, is durable, does not easily bend or crush, has high abrasion resistance, excellent low temperature characteristics, high fire resistance and heat resistance, and provides strength even at temperatures exceeding about 1400 degrees. It can be maintained, it can be made of a material having a high oxidation resistance, excellent workability and economy.

Depending on the design conditions, the pipe 20 may be made of stainless steel.

Furthermore, the pipe 20 allows the coolant to be received and transported. At this time, the coolant accommodated in the pipe is transferred into the cooling target 10 through the inlet 21 and heat is transferred into the cooling target 10. It is transferred to the outside of the cooling target 10 through the take-off part 22 and discharges the taken heat.

Preferably, as shown in FIG. 2, the inlet 21 may be installed at a position lower than the outlet 22 based on the cooling target 10 installed on the ground.

This is a solid state through the internal heat exchanger (30) in the course of the natural convection of the phase change material (Na (CH ₃ COO) 3 H ₂ O) contained in the coolant that is received and transported in the pipe 20 along the pipe 20 Is transferred to the outside of the cooling target 10 through the discharge unit 22 while being phase-converted to the liquid state, and is converted to the solid state from the liquid state by the external heat exchanger 40 than the discharge unit 22 by gravity. It is to be smoothly transferred to the inlet portion 21 provided at a low position to be drawn into the cooling target (10).

Thus, the coolant received and transported in the pipe 20 is introduced into the cooling target 10 through the inlet 21, and is transferred to the internal heat exchanger 30 of the cooling target 10 to be inside the cooling target 10. The heat formed in the cooling target 10 is transferred to the outside of the cooling target 10 through the discharge unit 22 so that the energy inside the cooling target 10 is discharged to the outside of the cooling target 10 through the external heat exchanger 40. .

Here, the refrigerant material is a mixture consisting of water and a phase change material (Na (CH ₃ COO) 3 H ₂ O).

The phase change material (Na (CH ₃ COO) 3H ₂ O) has a phase change temperature higher than the cooling target temperature (10) during the normal operation of the reactor and lower than the maximum temperature of the cooling target (10) during the event / incident. It is mixed with water and is stable in water, and is advantageous for flow.It has a high density between phases during phase transformation so that natural convection circulation is actively performed and high latent heat of phase transformation so as to absorb a lot of internal energy of the cooling target 10 per unit volume. Can be done.

Depending on the design conditions, it can be made of a variety of phase change material in consideration of individual requirements and power plant characteristics of the nuclear power plant.

As shown in FIGS. 3 and 4, the phase change material (Na (CH ₃ COO) 3 H ₂ O) absorbs heat inside the cooling target 10 during phase conversion from a solid state to a liquid state, and in a solid state. When the phase conversion to the liquid state may be made of a material that performs the function of preventing heat to the outside of the cooling target (10).

That is, the coolant mixed with water and a phase change material (Na (CH ₃ COO) 3H ₂ O) is accommodated in the pipe 20 and transported, and after being introduced into the cooling target 10 through the inlet 21, The discharge part 22 of the cooling object 10 is discharged to the outside of the cooling object 10 along the pipe 20, and the inlet part 21 is again along the pipe 20 provided outside the cooling object 10. It is conveyed to the side and circulates.

Furthermore, the phase change material (Na (CH ₃ COO) 3 H ₂ O) is stably mixed with water, so that the phase change material is smoothly transferred even in the solid state.

At this time, the phase conversion material (Na (CH ₃ COO) 3 H ₂ O) is able to absorb more heat in the cooling target 10 by the high heat of melting, higher than the temperature during the normal operation of the cooling target 10 and in case of an accident It is desirable to have a suitable melting temperature lower than the temperature, and that most of the phase conversion material (Na (CH ₃ COO) 3 H ₂ O) is stably dissolved in water to improve fluidity by high solubility, and the same volume by high density It can absorb a lot of heat, promote natural convection by high density difference during phase change, and because of low corrosiveness, diversify material selection of pipe 20 and test apparatus 100, and by high crystal growth rate It is a material that has excellent heat dissipation effect due to rapid cooling at, and prevents secondary accidents in case of leakage due to non-toxicity. To which the lure, preferably, may be formed of a phase change material _{(Na (CH 3 COO) 3H} 2 O) as determined in the test apparatus 100.

This phase change material (Na (CH ₃ COO) 3H ₂ O) has the chemical name of sodium acetate trihydrate, the melting point (melting point) is 58 ℃, the latent heat during phase conversion is 264 J / g, the density (Density) is 1.45kg / dm ³ , Specific heat is 2.79kJ / kgK, promotes natural convection by high density difference (13.28%) during phase conversion, and 78.2g / 100ml (water) at 0 ℃ And a high solubility of 138.8 / 100 ml (water) at 50 ° C.

Here, the test apparatus 100 is to determine the characteristics of the phase change material (Na (CH ₃ COO) 3 H ₂ O) included in the coolant among the candidate group of various phase change material, to be utilized in the cooling target (10) , Heating unit 110, the first tube 120, straight tube 130, inclined tube 140, including the cooling unit 150 and the second tube 160, for each connection between the components The core flange 101, the flange connection pipe 102, the right angle elbow 103, the straight connector 104, the connector connection pipe 105 and the inclined elbow 106 are configured.

The test apparatus 100 will be described in detail with reference to FIG. 5, which includes a heating unit 110, a first tube 120, corresponding to an internal heat exchanger 30 provided in the cooling target 10. Core Flange 101, Flange Connection Pipe 102, Right Angle Elbow 103, Straight Connector 104, Connector Connection Pipe 105, Inclined Elbow 106, Inclined Tube 140, Inclined Elbow 106, Cooling unit 150 corresponding to the connector connection pipe 105, the right angle elbow 103, the flange connection pipe 102, the core flange 101, the external heat exchanger 40 provided in the cooling target 10 ), Core flange 101, second tube 160, core flange 101, flange connection pipe 102, right angle elbow 103, connector connection pipe 105, inclined elbow 106, inclined tube ( 140, inclined elbow 106, connector connecting pipe 105, straight connector 104, straight tube 130, right angle elbow 103, flange connection pipe 102 and core flange 101 are sequentially connected Been lung As it may be in the form.

By transferring the coolant in the above configuration, the phase change material Na (CH ₃ COO) 3 H ₂ O is determined.

In this case, the heating unit 110 provided in the test apparatus 100 will be described with reference to FIG. 6, and a conveying pipe through which a coolant flows is provided inside, and a heating unit housing 111 surrounding the outside thereof is provided. A plurality of steam supply pipes 112 for supplying high pressure steam are provided in the heating unit housing 111.

Preferably, the steam supply pipe 112 is provided in a radial form around the transfer pipe through which the coolant flows, and as shown in the accompanying drawings, it may be provided with eight, and the maximum flow rate of the coolant located in the center is maximum. By supplying a high-pressure steam for heat transfer, the inner space of the heating unit housing 111 is configured not to communicate with the outside, thereby minimizing heat loss, it is possible to implement a high heat transfer coefficient.

In addition, when the cooling unit 150 provided in the test apparatus 100 is described with reference to FIG. 7, a cooling pipe flowing with a coolant therein is provided, and a cooling unit housing 151 surrounding the outside thereof is provided. Cooling water supply pipe 152 for supplying forced cooling water inside the cooling unit housing 151 is provided.

Preferably, the inner space of the cooling unit housing 151 is provided in the form of surrounding the transfer pipe flowing coolant so as not to communicate with the outside, the coolant supply pipe 152 may be formed in the shape of a fin tube or coil for high heat exchange have.

In addition, the transfer pipe through which the coolant provided in each of the heating unit 110 and the cooling unit 150 flows may be formed in a copper pipe shape, and the core flange 101 may be made of copper material.

In addition, the first tube 120 may be made of pyrex glass material so as to visually check the flow of the coolant passing through the heating unit 110.

In addition, the flange connection pipe 102 is made of a copper pipe, and serves to connect the core flange 101 and the right angle elbow 103.

In addition, the right angle elbow 103, the straight connector 104 and the inclined elbow 106 may be made of a copper material, the right angle elbow 103 connects the flange connection pipe 102 and the straight tube 130 or the flange The connecting pipe 102 and the connector connecting pipe 105 performs a function, the straight connector 104 performs a function of connecting the straight tube 130 and the connector connecting pipe 105, the inclined elbow 106 ) Performs a function of connecting the connector connecting pipe 105 and the inclined tube (140).

At this time, the inclination of the inclined elbow 106 is preferably made of about 22.5 °, as shown in Figure 5, provided with a pair on each of the upper side and the lower side, the coolant passed through the heating unit 110 is relatively It may be configured to pass through the first tube 120 having a long length, and the coolant passing through the cooling unit 150 passes through the second tube 160 having a relatively short length.

In addition, the connector connecting pipe 105 performs a function of connecting the straight connector 104 and the inclined elbow 106 or the inclined elbow 106 and the right angle elbow 103, in the form of a copper pipe Can be done.

On the other hand, the test apparatus 100 is made of a copper material or pyrex glass (pyrex glass) material, the closed circuit form due to the effect of the coefficient of thermal expansion due to different temperatures in the heating unit 110 and the cooling unit 150 The volume of the test apparatus 100 is expanded in a specific portion, the heat deformation is reduced in other specific portion occurs.

At this time, the straight connector 104, the connector connecting pipe 105 and the inclined elbow 106 made of copper material accommodates deformation caused by expansion and contraction due to thermal deformation, and has a closed circuit form. The device 100 can be minimized in case of breakage or deformation.

Further, as shown in FIG. 5, the connector connecting pipe 105 is made thinner than the thickness of the straight connector 104 and the slope elbow 106, so that the connector between the straight connector 104 and the slope elbow 106 is formed. By ensuring a free space along the outer diameter of the connecting pipe 105, even if the test apparatus 100 is deformed by the soft deformation, the connector connecting pipe 105 absorbs the bending force by the free space and can flexibly cope with it. Do it.

According to the design conditions, the linear connector 104, the connector connecting pipe 105 and the inclined elbow 106 may be provided with an elastic member 170 on the outer peripheral surface.

Referring to FIG. 8, the elastic member 170 is formed in a torsion coil spring (torsion spring), and both ends thereof are coupled to and fixed to the outer circumferential surfaces of the linear connector 104 and the inclined elbow 106, respectively.

Preferably, it is coupled to the outer circumferential surface of the linear connector 104 and the inclined elbow 106, of course, may be coupled to each of the front and rear sides can be made in a pair.

At this time, the angle between the protruding ends of the elastic member 170 may be made of about 22.5 ° the inclination angle of the inclined elbow 106.

Therefore, even if bending occurs in the straight connector 104, the connector connecting pipe 105 and the inclined elbow 106 due to thermal deformation, the test apparatus 170 is returned to its original shape by the restoring force of the elastic member 170. Can be induced.

The straight tube 130 is connected between the right elbow 103 and the straight connector 104, made of a pyrex glass material can be made to visually check the flow of the coolant passed through the heating unit 110. have.

In addition, the inclined tube 140 performs a function of connecting between a pair of inclined elbow 106, made of pyrex glass material to visually check the flow of the coolant, inclined elbow 106 Likewise, the inclination of the inclined tube 140 may be about 22.5 °.

In addition, the second tube 160 may be made of pyrex glass to visually check the flow of the coolant passing through the heating unit 110.

The flange connection pipe 102, the connector connection pipe 105, the heating unit 110, the first tube 120, the straight tube 130, the inclined tube 140, cooling in the test device 100 made of such a configuration When the ratio of the length of the unit 150 and the second tube 160 is described with reference to Figure 5, it may be made of 1.5: 1: 40: 50: 20: 30.2: 40: 20.

As shown in FIG. 5, the inclined tube 140 has an inclination of about 22.5 °, thereby converting phase-converting material (Na (CH ₃₎ that absorbs heat while converting phase from solid to liquid in the heating unit 110. COO) 3H ₂ O) is passed through the inclined tube 140 through the first tube 120 and the straight tube 130, the flow is accelerated to be quickly transferred to the cooling unit 150, the same as the cooling unit ( The phase conversion material (Na (CH ₃ COO) 3H ₂ O), which emits heat absorbed as it is phase-converted from liquid to solid in 150, passes through the inclined tube 140 through the second tube 160 to accelerate the flow. It can be quickly transferred to the straight tube 130 and the heating unit 110.

Depending on the design conditions, the test apparatus 100 may be provided with a separate measuring unit (not shown in the drawing) to measure the temperature, pressure, flow rate and density between each component, preferably, visually confirmed Selected one of the first tube 120, the straight tube 130, the inclined tube 140, the second tube 160 and the heating unit 110, the cooling unit 150 made of a possible pyrex glass material It goes without saying that the measurement unit may be provided in the above configuration.

In addition, the test apparatus 100 is composed of a closed circuit in which the entire configuration is connected, so that the coolant for phase conversion from liquid to solid and phase to solid from liquid does not evaporate, so that continuous phase conversion and circulation can be achieved. Make sure

The nuclear power plant passive cooling system using the solid and liquid phase change material according to the present invention through the test apparatus 100 having such a configuration absorbs a lot of heat with a relatively small volume expansion during the phase change, Allow the phase change material (Na (CH ₃ COO) 3H ₂ O) to be released to be determined.

That is, when the phase change of the phase change material (Na (CH ₃ COO) 3H ₂ O), the volume change can be measured and based on this, the phase change density difference can be evaluated, and the temperature limit value is set to about 40 ° C. to maintain the temperature limit value. The heat removal rate can be evaluated by the maximum exothermic measurement value, and the operating time can be evaluated by measuring the time to maintain the temperature limit value (about 40 ° C.).

Therefore, measuring the driven cooling properties of the phase change materials _{(Na (CH 3 COO) 3H} 2 O) , and by predicting a natural convection force in accordance with the phase change of the phase change materials _{(Na (CH 3 COO) 3H} 2 O) , The phase change material (Na (CH ₃ COO) 3 H ₂ O) included in the coolant is determined.

Accordingly, the phase conversion material (Na (CH ₃ COO) 3 H ₂ O) determined by the test apparatus 100 is determined by the cooling performance according to the natural circulation rate and heat absorption capacity, as shown in [Equation 1] below Likewise, it is possible to obtain the natural circulation rate, and it can be seen that the driving force of the natural circulation is generated by the density difference of the phase change material (Na (CH ₃ COO) 3 H ₂ O).

[Equation 1]

,

Where C _D is the drag coefficient, A is the flow cross-sectional area of the hottest point fluid, ρ1 is the lowest temperature density and ρ2 is the highest temperature density.

As a result, the phase change material (Na (CH ₃ COO) 3 H ₂ O) has a melting temperature of about 58.4 ° C. and a density difference of 13.28% at the time of phase conversion.

That is, due to the appropriate melting temperature of about 58.4 ° C. of the phase change material (Na (CH ₃ COO) 3H ₂ O), the phase change material is higher than the normal operation in the cooling target 10 and is lower than the temperature at the time of the accident to perform phase transformation only in the event of an accident. Make sure

In addition, the heat absorption capacity at the same temperature conditions can be seen through the following [Equation 2].

[Equation 2]

Where q is the heat absorption capacity per unit weight, c _p is the average specific heat and ΔT is the difference between the highest temperature and the lowest temperature.

Looking at the heat absorption capacity per unit weight of the phase conversion material (Na (CH ₃ COO) 3 H ₂ O) using the above [Equation 2], it can be seen through the following [Equation 3].

[Equation 3]

Here, c _p1 is a specific heat when the phase conversion material (Na (CH ₃ COO) 3 H ₂ O) is in a solid state, c _p2 is a liquid phase conversion material (Na (CH ₃ COO) 3 H ₂ O) is a liquid Specific heat in the liquid state, ΔT ₁ and ΔT ₂ is 58 ℃ where the phase change of the phase change material (Na (CH ₃ COO) 3 H ₂ O) occurs when the temperature is 20 ℃ (50 ℃ ~ 70 ℃) ΔT ₁ means 8 ° C (58 ° C-50 ° C), ΔT ₂ means 12 ° C (70 ° C-58 ° C), and the phase change material (Na (CH ₃ COO) 3 H ₂ O) The phase conversion energy of is 264kJ / kg ℃.

Therefore, the heat absorption capacity q per unit weight of the phase change material (Na (CH ₃ COO) 3 H ₂ O) through [Equation 3] is 322 kJ / kg ℃ by the formula (8) + (12) + 264 Can be.

In addition, in the nuclear power plant passive cooling system using a solid, liquid phase change material according to the present invention, the coolant is a phase change material (Na (CH ₃ COO) 3H ₂ O) which is phase-converted from solid to liquid or liquid to solid with water. Since the phase conversion from the liquid to the gas that occurs about 1,000 times the volume increase is not made, the configuration is very simple, there is an advantage that can be miniaturized the passive cooling system of the nuclear power plant.

These phase change materials Looking in more detail, the volume rate of change of _{(Na (CH 3 COO) 3H} 2 O), phase change materials _{(Na (CH 3 COO) 3H} 2 O) density when the solid state is 1450kg / m ^3, and When the phase change material (Na (CH ₃ COO) 3H ₂ O) is in the liquid state, the density is 1280kg / m ^3, so the volume increase rate at the time of phase change (condition: based on 1 atm, temperature of about 58 ° C) is about It can be seen that 1.133 times.

In other words, when using a phase change material that is phase-converted into a liquid and a gas, it is possible to omit an appropriate device or equipment corresponding to a sudden volume change and pressure change, and the phase change material (Na (CH) _{By using 3} COO) 3H ₂ O), there is an advantage that the configuration of the passive cooling system of the nuclear power plant can be simplified and the cooling system can be miniaturized by minimizing the volume change during phase conversion.

At this time, the coolant contained in the test apparatus 100 includes water and a phase change material (Na (CH ₃ COO) 3 H ₂ O), but with respect to 100 parts by weight of water phase change material (Na (CH ₃ COO) 3 H ₂ O) may be composed of 70 to 200 parts by weight.

Such a coolant has a slight degree of absorbing heat inside the cooling target 10 when the phase change material (Na (CH ₃ COO) 3 H ₂ O) is less than 70 parts by weight (minimum part) with respect to 100 parts by weight of water. When the phase change material (Na (CH ₃ COO) 3H ₂ O) exceeds 200 parts by weight (maximum parts by weight) with respect to 100 parts by weight of water, a phase conversion material in a solid state is obtained. There is a problem in that the transfer is not smoothly accommodated in the pipe 20 in proportion to the water.

The phase change material (Na (CH) based on 100 parts by weight of water through such a test apparatus 100 ₃ COO) 3H ₂ O) CFD analysis (temperature distribution) results of the coolant and water containing 70 to 200 parts by weight with reference to Figure 9, when the other conditions are the same in the above [Equation 1], affects the driving force circulating naturally Looking at the difference in density, when the 20 ℃ (50 ℃ ~ 70 ℃), the density difference of water is 1%, while the phase change material (Na (CH ₃ COO) 3H ₂ The phase difference of O is 13.3%, so the phase change material Na (CH ₃ COO) 3H ₂ The natural circulation rate due to the phase transformation of O) is about 3.6 times the rate at which the water circulates, thereby significantly improving the cooling efficiency.

That is, phase change material (Na (CH ₃ COO) 3H ₂ O) has better circulation than water, and as a result, the cooling efficiency can be significantly improved. Through the above [Equation 2] and [Equation 3], the phase change material (Na (CH) ₃ COO) 3H ₂ When comparing the heat absorption capacity of O) with water, when the 20 ° C (50 ° C ~ 70 ° C) is changed, the heat absorption capacity of the water is 84 kJ / kg ° C (specific heat of water 4.2 × difference between the highest and lowest temperature 20 (70-50) ), While the phase-converting material (Na (CH) ₃ COO) 3H ₂ The heat absorption capacity of O) is 322kJ / kg ℃, so the phase change material (Na (CH) is changed when 20 ℃ (50 ℃ ~ 70 ℃) is changed. ₃ COO) 3H ₂ The heat energy that O) can absorb is about 3.8 times that of water, so that cooling can be performed more efficiently.

Accordingly, in the nuclear power plant passive cooling system using the phase change material according to the present invention, the test device 100 is a coolant made of water and a phase change material (Na (CH ₃ COO) 3H ₂ O) is accommodated therein, the heating unit The phase change material (Na (CH ₃ COO) 3 H ₂ O) passing through the 110 is phase-converted from the solid state to the liquid state, and absorbs heat in the heating unit 110. At this time, the coolant rises along the first tube 120 by buoyancy due to the significant density difference between the phases generated by the phase change material Na (CH ₃ COO) 3 H ₂ O in the heating unit 110. The straight elbow 103 passes through the straight tube 130 and the straight connector 104.

Next, the flow of the coolant is accelerated by the inclination of the inclined elbow 106 and the inclined tube 140 while passing through the inclined elbow 106 and the inclined tube 140, and is transferred to the cooling unit 150 to a liquid state. As the phase transition from the solid state to the release of the solidified and absorbed heat, a remarkable density difference between the phases again occurs to accelerate the convection of the cooling zone is transferred to the right elbow 103 along the second tube (160).

Next, while passing through the inclined elbow 106 and the inclined tube 140, the flow of the coolant is accelerated once more by the inclination of the inclined elbow 106 and the inclined tube 140, the straight connector 104, the straight tube Passed through the 130 and the right angle elbow 103 to the heating unit 110.

The test apparatus 100 having such a configuration determines the phase change material (Na (CH ₃ COO) 3 H ₂ O) available in the cooling target 10, thereby determining the phase change material (Na determined in the test device 100). (CH ₃ COO) 3H ₂ O) can be used to passively remove heat inside the cooling target 10.

In addition, by using the external atmosphere of the cooling target as the final heat removal source, there is an advantage that can be cooled without external power, because no separate operator action, such as supply of electricity or cooling water, does not require operator intervention. That is, the phase change material Na (CH ₃ COO) 3 H ₂ O is introduced into the cooling target 10 through the inlet 21 as illustrated in FIGS. 10 and 11, and It is transferred to the internal heat exchanger (30) to take heat due to the temperature rise inside the cooling target (10) is moved to the outside of the cooling target (10) through the discharge unit 22, the cooling target (10) through the external heat exchanger (40) The internal energy is discharged to the atmosphere outside the cooling target 10.

In addition, the fluid of the cooling system containing a phase conversion material (Na (CH ₃ COO) 3 H ₂ O) by natural convection circulation by a significant density difference between the phases generated during the phase conversion in the internal / external temperature range of the cooling target, There is an advantage that cooling can be performed in the long term without time limitation.

In addition, by using the phase change material (Na (CH ₃ COO) 3 H ₂ O) determined by the test apparatus 100, it is possible to absorb more heat in the cooling target by the high heat of fusion (264 J / g), Operation is possible only when an accident occurs due to the melting temperature (58.4 ℃) that is higher than the normal operation temperature and lower than the accident temperature, and 78.2g / 100ml (water) at 0 ℃, and 138.8 / 100ml (water at 50 ℃) Due to its high solubility, many phase-converting materials (Na (CH ₃ COO) 3H ₂ O) are soluble in water, improving the fluidity due to natural convection, and the high density of 1.45kg / dm3 Heat absorption is possible, and natural convection promotion can be improved by high density difference (13.28%) during phase conversion.

Meanwhile, check valves 51 and 52 are provided outside the object to be cooled 10, respectively, in the part of which the inlet part 21 is provided and the part of which the outlet part 22 is provided. Can be.

The check valves 51 and 52 allow the fluid to flow in only one direction and not in the opposite direction, and the coolant contained in the pipe 20 sequentially circulates the inlet part 21 and the outlet part 22 sequentially. So that it can flow in one direction.

However, since the installation of the check valves 51 and 52 may interfere with the flow of the coolant flowing passively, the check valves 51 and 52 may be installed only when necessary.

Depending on the design conditions, the buffer tank 60 connected to the pipe 20 may be provided.

The buffer tank 60 is connected to one side or the other side of the pipe 20, the function of the coolant to accommodate the volume change generated in the phase conversion process and to prevent impurities from flowing into the system. In addition, when the pressure or flow rate of the coolant received and transported in the pipe 20 is changed rapidly, it performs a function that does not affect the other side or one side that is the other side where the buffer tank 60 is not installed.

In this case, the buffer tank 60 may further include a relief valve 61 and an air valve 62.

The relief valve 61 allows the fluid inside the system to be ejected to the outside when the pressure in the pipe 20 and the buffer tank 60 becomes higher than the predetermined pressure, thereby preventing the system pressure from exceeding the design pressure. Maintains soundness.

The air valve 62 allows external air to flow into the buffer tank 60 and the pipe 20 to prevent negative pressure inside the system.

According to the design conditions, the gas discharge and air inflow by the buffer tank 60 may be configured to check the pressure in the pipe 20, and to be passively operated by the checked pressure value.

Accordingly, as the coolant conveyed along the pipe 20 is phase-converted to a liquid state, a solid state, or a gas state, the phase change material in the present invention may be maintained by maintaining a constant pressure even when expansion or contraction occurs. Cooling with Na (CH ₃ COO) 3H ₂ O) can be performed smoothly.

In the above description, various embodiments of the present invention have been described and described, but the present invention is not necessarily limited thereto, and a person having ordinary skill in the art to which the present invention pertains can make various changes without departing from the technical spirit of the present invention. It will be appreciated that branch substitutions, modifications and variations are possible.

10: cooling target 20: piping
21: inlet 22: outlet
30: internal heat exchanger 40: external heat exchanger
51, 52: check valve 60: buffer tank
61: relief valve 62: air valve
100: test apparatus 101: core flange
102: flange connection pipe 103: right angle elbow
104: straight connector 105: connector connection pipe
106: inclined elbow 110: heating part
111: heating unit housing 112: steam supply pipe
120: first tube 130: straight tube
140: inclined tube 150: cooling unit
151: cooling unit housing 152: cooling water supply pipe
160: second tube 170: elastic member

Claims (11)

A pipe 20 including an inlet part 21 communicating with the inside of the cooling target 10 and an outlet part 22 communicating with the outside, wherein the coolant is received and transferred inside / outside;
An internal heat exchanger 30 connected to the pipe 20 provided in the cooling target 10; And
It is configured to include; an external heat exchanger (40) connected to the pipe 20 provided outside the cooling target (10),
The coolant is
A solvent contained in the pipe 20,
It is drawn into the cooling target 10 through the inlet 21, discharged to the outside of the cooling target 10 through the discharge unit 22, and inside and outside the cooling target 10 along the pipe 20. It is characterized in that the phase conversion material (Na (CH ₃ COO) 3 H ₂ O) determined by the test device (PCM LOOP, 100) for discharging the heat inside the cooling target 10 to the outside,
The test device 100
The heating unit 110, the first tube 120, the straight tube 130, the inclined tube 140, the cooling unit 150, the second tube 160, the inclined tube 140 and the straight tube 130 are It consists of a closed circuit provided in sequence,
A heating unit 110 for supplying heat to a transfer pipe through which coolant flows;
A first tube 120 through which a phase change material (Na (CH ₃ COO) 3 H ₂ O) having undergone phase conversion in the heating part 110 rises and passes;
A straight tube 130 connected to the heating unit 110 and the first tube 120 at right angles;
An inclined tube 140 connected to the straight tube 130 in an inclined form;
A cooling unit 150 spaced apart from the heating unit 110 and cooling the transfer pipe through which coolant flows; And
And a second tube 160 through which the phase change material (Na (CH ₃ COO) 3H ₂ O) having undergone a phase change in the cooling unit 150 passes while descending. Passive cooling system for nuclear power plants using converting materials.
delete The method according to claim 1,
The heating unit 110 and the cooling unit 150 is made of a copper pipe form,
The first tube 120, the straight tube 130, the inclined tube 140 and the second tube 160 is a nuclear power plant using a solid, liquid phase change material, characterized in that made of pyrex glass material Cooling system.
The method according to claim 3,
The ratio of the length of the heating unit 110, the first tube 120, the straight tube 130, the inclined tube 140, the cooling unit 150 and the second tube 160 is 40: 50: 20 : 30.2: A nuclear power plant passive cooling system using solid, liquid phase change material, characterized in that consisting of 20: 20.
The method according to claim 4,
The angle formed by the straight tube 130 and the inclined tube 140 is made of 22.5 °, the nuclear power plant passive cooling system using a solid, liquid phase conversion material, characterized in that the inclined tube 140 is provided in an inclined form. .
The method according to claim 1,
The heating unit 110
A heating unit housing 111 surrounding the outside of the transfer pipe through which the refrigerant flows; And
The nuclear power plant passive cooling system using a solid, liquid phase conversion material, characterized in that comprises a; steam supply pipe (112) for supplying high pressure steam in the heating unit housing (111).
The method according to claim 1,
The cooling unit 150
Cooling unit housing 151 surrounding the outside of the transfer pipe flowing refrigerant; And
And a cooling water supply pipe (152) for supplying forced cooling water into the cooling unit housing (151). The nuclear power plant passive cooling system using a solid and liquid phase change material, characterized in that it comprises a.
The method according to claim 7,
The cooling water supply pipe 152
Nuclear power plant passive cooling system using a solid, liquid phase change material, characterized in that the fin tube form or coil form.
The method according to claim 1,
The test device 100
The core flange 101 is connected between the heating unit 110 and the first tube 120, the cooling unit 150 and the second tube 160,
At each end of the heating unit 110 and the first tube 120, a flange connection pipe 102 coupled to the core flange 101, a flange connection pipe 102, and a straight tube ( 130 is provided with a right angle elbow 103 for connecting at right angles,
Between the straight tube 130 and the inclined tube 140, a straight connector 104 coupled to the straight tube 130, the inclined elbow 106 of the inclined form coupled to the inclined tube 140 and the straight connector Connector connection pipe 105 for connecting the 104 and the slope elbow 106 is provided,
At the ends of each of the cooling unit 150 and the second tube 160, a flange connection pipe 102 coupled to the core flange 101 and a flange connection pipe 102 coupled to the core flange 101 are formed at right angles to the flange connection pipe 102. The right angle elbow 103 to be coupled, the connector connection pipe 105 coupled to the right angle elbow 103 and the inclined elbow 106 of the inclined shape connecting the connector connection pipe 105 and the inclined tube 140 is A passive nuclear cooling system using a solid, liquid phase conversion material, characterized in that provided.
The method according to claim 9,
The core flange 101, the flange connection pipe 102, the right angle elbow 103, the straight connector 104, the connector connection pipe 105 and the slope elbow 106 is made of a copper pipe,
The right angle elbow (103) has an inclination angle of 90 °, the inclined elbow 106 is a nuclear power plant passive cooling system using a solid, liquid phase conversion material, characterized in that configured to have an inclination angle of 22.5 °.
The method according to claim 10,
The flange connection pipe 102, the connector connection pipe 105, the heating unit 110, the first tube 120, the straight tube 130, the inclined tube 140, the cooling unit 150 and the second tube ( The ratio of the length of the 160 is composed of 1.5: 1: 40: 50: 20: 30.2: 40: 20, the nuclear power plant passive cooling system using a solid, liquid phase conversion material.

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