JP2018538509A - Post-use nuclear fuel passive cooling system using heat pipe - Google Patents

Abstract

A storage water tank filled with cooling water, a number of fuel rods, a number of guide pipes whose upper and lower ends are opened, a post-use nuclear fuel assembly stored in the storage water tank, and a number of branch pipes And a heat pipe module having a condensing part communicating with the multiple branch pipes, wherein the multiple branch pipes are respectively inserted into the multiple guide pipes. To provide a passive cooling system for nuclear fuel assemblies. According to the present invention, even when a cooling water pump of a post-use nuclear fuel storage facility does not operate due to a complete power loss accident inside or outside the power plant of the nuclear power plant, the post-use nuclear fuel decay heat is passively transferred by natural circulation of a heat pipe solvent. Therefore, it is possible to improve the safety of nuclear fuel and nuclear fuel after use by preventing serious accidents. Moreover, since the passive cooling system according to the present invention does not require complicated control of the cooling system, it is possible to simplify the design of safety equipment and to reduce the cost through this. Moreover, the passive cooling system according to the present invention can be installed in the post-use nuclear fuel storage facility on the nuclear power plant currently in operation with only a simple design change. Therefore, the safety of the post-use nuclear fuel can be reduced at a low cost. It can be greatly improved. [Selection] Figure 5

Description

The present invention relates to a passive cooling system for post-use nuclear fuel, and more specifically, by removing residual heat including decay heat of post-use nuclear fuel using a heat pipe, the inside and outside of a power plant The present invention relates to a passive cooling system for post-use nuclear fuel that can prevent serious accidents even in the event of a complete blackout.

Nuclear power generation that uses the nuclear fission energy of radioactive materials to produce electric power, despite its high economic efficiency, requires a number of engineering safety equipment such as radioactive spill prevention equipment and nuclear waste storage equipment.

However, if the functions of these safety facilities are lost due to external factors such as sudden accidents, earthquakes, and tsunamis that exceed the design standards, serious accidents such as radioactive material spills may occur, which occurred in March 2011. The Japan Fukushima nuclear accident was a typical example.

On the other hand, post-use nuclear fuel discharged after being used as fuel in a nuclear reactor continues to generate high heat and radioactivity called “decay heat”. It is essential to build a cooling system that can properly remove spill prevention equipment and decay heat.

In general, after-use nuclear fuel is stored for about 10 to 20 years in a storage facility installed in the site of the nuclear power plant, and then transferred to a permanent storage facility. Post-use nuclear fuel storage facilities are roughly divided into water-cooled wet storage facilities that are stored in storage tanks and air-cooled dry storage facilities that are stored inside dry containers (cask, silo, etc.) made of metal and / or concrete. Is done.

FIG. 1 shows a wet storage facility 10 for nuclear fuel after use, a storage tank 11 having a depth of about 12.8 m, and a rack that supports and maintains a large number of post-use nuclear fuel assemblies. 20, and a cooling water supply pipe 15 and a cooling water discharge pipe 16 that are respectively installed on one side and the other side of the storage water tank 11 and supply and discharge the cooling water 12. The inside of the storage water tank 11 is filled with the cooling water 12 at such a height that the storage table 20 can be sufficiently immersed (eg, about 12 m).

Although not shown, the cooling water supply pipe 15 and the cooling water discharge pipe 16 form a circulation loop including a pump, and the cooling water discharged to the cooling water discharge pipe 16 is cooled through the heat exchange section. Thereafter, the water is again supplied to the storage water tank 11 through the cooling water supply pipe 15.

As shown in FIG. 2, the storage base 20 includes a large number of mounting grooves formed in the vertical direction, and a post-use nuclear fuel assembly 200 is inserted into each mounting groove.

In general, as shown in FIG. 3, a nuclear fuel assembly 200 ′ installed in a nuclear reactor includes a plurality of support grid bodies 220 each including a plurality of cells and spaced apart in the longitudinal direction, and a support grid body. 220 includes a plurality of fuel rods 210 inserted for each cell, and an upper support 230 and a lower support 240 coupled to upper and lower ends of the multiple fuel rods 210, respectively.

In addition, as shown in FIG. 4, a large number of control rod guide tubes 231, 232, 233 and 234 and a measuring instrument guide tube 235 are inserted into the support grid 220 in the vertical direction, and the control rod guide tubes 231 and 232 are inserted. 233, 234 and the instrument guide tube 235 function as a frame for maintaining the form of the nuclear fuel assembly 200 ′ by being coupled to a large number of support grids 220 arranged above and below by welding or the like.

The control rod guide tubes 231, 232, 233, and 234 are provided as passages into which the control rods provided inside the nuclear reactor are inserted, and the instrument guide tube 235 is provided as a passage into which instrument cables and the like are inserted. Is done.

FIG. 4 shows that the nuclear fuel assembly 200 includes four control rod guide tubes 231, 232, 233, 234 and one measuring instrument guide tube 235. The number and positions of the guide tubes are as follows. It varies depending on the model.

Meanwhile, the upper support 230 may include guide tube nozzles corresponding to the respective guide tubes, and the lower support 230 may include a lower nozzle for supplying core cooling water. In general, the upper support 230 including the guide tube nozzle and the lower support 240 including the lower nozzle are removed from the nuclear fuel assembly 200 ′ of FIG. 3 and inserted into the storage table 20 of the storage tank.

However, in order to maintain the wet storage facility 10 as shown in FIG. 1 normally, the cooling water 12 stored in the storage water tank 11 must be forcedly circulated and cooled using a pump.

If the cooling water is not forcedly cooled, the cooling water will boil and evaporate due to the decay heat of the post-use nuclear fuel, and the post-use nuclear fuel will be exposed outside the water, causing damage to the nuclear fuel and causing radioactive materials to flow out. Sometimes. In more serious cases, the temperature may rise rapidly due to decay heat, and a large amount of hydrogen may be generated during the process of oxidizing the nuclear fuel cladding after use, resulting in a hydrogen explosion. Damage to the containment facility causes various radioactivity and pollutants to spread to the surrounding area, resulting in serious environmental pollution and human lives.

Therefore, an emergency battery capable of driving the pump even in the event of a complete power failure is always installed in the wet storage facility 10 for nuclear fuel after use. However, the emergency battery has a limited period of use, so if the disaster situation such as a power outage is long, there is a problem that the function cannot be performed, and if the power distribution system or cooling system is damaged by an earthquake etc. However, there is a problem that the above-mentioned serious accident may occur because the nuclear fuel cannot be cooled correctly after use.

For these reasons, it is necessary to prepare facilities that can maintain the safety of the nuclear fuel storage tank after use even in the event of a complete loss of power inside and outside the power plant, especially after the Fukushima nuclear power plant accident, even when power is not supplied. Research and development on a passive cooling system that can appropriately remove the decay heat of the plant and prevent serious accidents has been actively conducted internationally.

Korean Registered Patent No. 10-1494372 US Patent Application Publication No. 2015/0060018

The present invention has been devised in such a background. The purpose of the present invention is to remove the decay heat of nuclear fuel after use passively even in the event of a complete loss of power inside and outside the nuclear power plant. It is an object to provide a passive cooling system that can prevent nuclear power generation and improve the safety of nuclear power plants.

Another object of the present invention is to provide a passive cooling system that can more effectively remove the decay heat of post-use nuclear fuel stored in a storage tank or dry container using a heat pipe.

Another object of the present invention is to provide a passive cooling system for post-use nuclear fuel that does not require complicated control and has a simple configuration, so that it can be easily applied to a storage facility that is currently in operation. There is.

The uniform phase of the present invention includes a storage tank filled with cooling water, a number of fuel rods and a number of guide pipes whose upper and lower ends are open, and a post-use nuclear fuel assembly stored in the storage tank; And a heat pipe module including a condensing part communicating with the multiple branch pipes, wherein the multiple branch pipes are respectively inserted into the multiple guide pipes. A passive cooling system for post-use nuclear fuel assemblies is provided.

In the passive cooling system for a post-use nuclear fuel assembly according to the uniform phase of the present invention, the upper space of the storage tank is surrounded by a shielding wall, and the condensing part of the heat pipe module is provided outside the shielding wall. It can be located inside the air cooling section.

The air cooling unit includes an elevating unit that is installed at an upper end of the shielding wall and supports each of the plurality of heat pipe modules, and a bellows that connects a peripheral part of the elevating unit and an upper end of the shielding wall. May be coupled to the elevating unit.

Another aspect of the present invention includes an inner container, an outer container that surrounds the inner container with an air channel interposed therebetween, an inlet and an outlet that are formed in the outer container and communicate with the air channel. A post-use nuclear fuel assembly stored in the inner container, a vaporization section composed of a number of branch pipes, and the number of branch pipes. A passive cooling system for a post-use nuclear fuel assembly, wherein the multiple branch pipes are inserted into the multiple guide pipes, respectively. .

In a passive cooling system for a post-use nuclear fuel assembly according to another aspect of the present invention, the condensing part of the heat pipe module may be located inside the air flow path.

In a passive cooling system for a post-use nuclear fuel assembly according to one aspect or the other aspect of the present invention, the multiple guide tubes include a control rod guide tube and an instrument guide tube, and the number of the multiple branch tubes is: The number of the multiple guide tubes may be the same.

In the passive cooling system for a post-use nuclear fuel assembly according to the present invention, the post-use nuclear fuel assembly includes an upper assembly and a lower assembly stacked one above the other. Each of the branch pipes may be inserted into a corresponding guide pipe of the upper assembly and a corresponding guide pipe of the lower assembly.

Further, in the passive cooling system of the post-use nuclear fuel assembly according to the uniform phase or other aspects of the present invention, the multiple branch pipes are respectively inserted into the multiple guide pipes from the lower ends of the post-use nuclear fuel assemblies. Can do.

According to the present invention, even when the cooling water pump of the post-use nuclear fuel storage facility does not operate due to a complete power loss accident inside or outside the nuclear power plant, the post-use nuclear fuel decay heat is passively removed by natural circulation of the heat pipe solvent. It is possible to improve the safety of nuclear fuel and nuclear fuel after use by preventing serious accidents.

Moreover, since the passive cooling system according to the present invention does not require complicated control of the cooling system, it is possible to simplify the design of safety equipment and to reduce the cost through this.

In addition, the passive cooling system according to the present invention can be installed in a post-use nuclear fuel storage facility on the currently operating nuclear power plant with only a simple design change. Therefore, the safety of the post-use nuclear fuel can be reduced. Can be greatly improved.

It is the figure which showed the conventional post-use nuclear fuel wet containment facility schematically. It is the figure which showed the state in which the nuclear fuel after use was inserted in the containment stand. It is the figure which illustrated the nuclear fuel assembly. It is the figure which illustrated many guide tubes with which a nuclear fuel assembly was equipped. It is a block diagram of the post-use nuclear fuel passive cooling system concerning the 1st Embodiment of this invention. It is the figure which showed the heat pipe module used for the post-use nuclear fuel passive cooling system concerning the 1st Embodiment of this invention. It is the figure which showed the form with which a heat pipe module is couple | bonded with a nuclear fuel assembly after use. It is the figure which illustrated various modifications of the after-use nuclear fuel passive cooling system concerning a 1st embodiment of the present invention. It is the figure which illustrated various modifications of the after-use nuclear fuel passive cooling system concerning a 1st embodiment of the present invention. It is the figure which illustrated various modifications of the after-use nuclear fuel passive cooling system concerning a 1st embodiment of the present invention. It is the figure which showed the form which raises / lowers a heat pipe module in FIG. It is a block diagram of the post-use nuclear fuel passive cooling system concerning the 2nd Embodiment of this invention.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

For reference, when one element is “connected” or “coupled” to another component in the present specification, not only when the element is directly coupled or coupled to the other component, It includes cases where they are indirectly connected or coupled with other elements in between. However, when one component is “directly connected” or “directly coupled” with another component, it means that no other component is interposed therebetween. In addition, unless specifically stated to the contrary, “including” a component having a certain part does not exclude other components, and further includes other components, or It means that it can have. Further, in the drawings attached to the present specification, some components are exaggerated so as to be different from actual ones, but this is merely for convenience of explanation and understanding, Of course, the scope of the invention should not be limitedly analyzed or distorted.

First Embodiment A first embodiment of the present invention relates to a wet-type post-use nuclear fuel passive cooling system (hereinafter referred to as a “wet passive cooling system”).

As shown in the schematic configuration diagram of FIG. 5, the wet passive cooling system 300 according to the first embodiment of the present invention includes the storage water tank 11 in which the cooling water 12 is filled to a predetermined height, and the interior of the storage water tank 11. And a plurality of post-use nuclear fuel assemblies 200 inserted into the respective insertion holes of the storage base.

Further, a cooling water supply pipe 15 and a cooling water discharge pipe 16 installed on one side and the other side of the storage water tank 11, respectively, and a pump (not shown) connected to the cooling water supply pipe 15 and the cooling water discharge pipe 16 including. The upper space of the storage water tank 11 is surrounded by a shielding wall 18 for preventing radioactive outflow and is isolated from the outside.

On the other hand, the wet passive cooling system 300 according to the first embodiment of the present invention includes a heat pipe module 100 that transfers heat from the vaporization unit 110 to the condensing unit 130 using a phase change of the refrigerant. The vaporizing unit 110 of the pipe module 100 is characterized in that it is installed so as to be inserted into the nuclear fuel assembly 200 after use.

The heat pipe module 100 includes a vaporizing unit 110, a condensing unit 130, and a connecting unit 120 that connects the vaporizing unit 110 and the condensing unit 130. The vaporization unit 110 is a portion that is inserted into the nuclear fuel assembly 200 after use, and the condensing unit 130 is a portion that is installed inside the air cooling unit 17 provided outside the shielding wall 18 and exchanges heat with the atmosphere. is there. It is preferable that a large number of radiating fins 150 are coupled to the condensing unit 130.

A normal heat pipe is composed of a single tube. However, as shown in FIGS. 6 and 7, the heat pipe module 100 according to the embodiment of the present invention has a large number of branch pipes 111 and 112 at one end. , 113, 114, 115 have a unique structure. Also in this case, the inside of each branch pipe 111, 112, 113, 114, 115 must communicate with the inside of the connecting part 120, and the inside of the connecting part 120 must communicate with the inside of the condensing part 130. Of course.

A number of branch pipes 111, 112, 113, 114, and 115 correspond to the vaporization unit 110, and as shown in FIG. 7, control rod guide pipes 251 provided in one post-use nuclear fuel assembly 200, 252, 253, 254 and the measuring instrument guide tube 255, respectively.

That is, the post-use nuclear fuel assembly 200 and the heat pipe module 100 are installed in a one-to-one correspondence, and each branch pipe 111, 112, 113, 114, 115 of the heat pipe module 100 corresponds to the corresponding post-use nuclear fuel assembly 200. Are inserted into the control rod guide tubes 251, 252, 253, 254 and the measuring instrument guide tube 255, respectively.

When the branch pipes 111, 112, 113, 114, and 115 are inserted into the guide pipes 251, 252, 253, 254, and 255 of the post-use nuclear fuel assembly 200 in this way, the branch pipes of the heat pipe module 100 are connected to the fuel rods. This has the advantage that it can be very close to 210, thereby absorbing and removing the hot decay heat generated from the fuel rods 210 more quickly and effectively.

On the other hand, in the post-use nuclear fuel assembly 200, the lower ends of the control rod guide tubes 251, 252, 253, 254 may be clogged, and the upper end of the measuring instrument guide tube 255 may be clogged. In such a case, before storing the used nuclear fuel assembly 200 in the storage tank 11, the lower ends of the control rod guide tubes 251, 252, 253, 254 and the upper end of the instrument guide tube 255 are opened, It is preferable that both ends are opened. However, the upper end of the measuring instrument guide tube 255 may be opened when the upper support 230 shown in FIG. 3 is removed.

If both ends of each guide tube 251, 252, 253, 254, 255 are opened, not only can the cooling efficiency be improved by the flow of the cooling water, but also the post-use nuclear fuel assembly 200 is set as described later. In the case of stacking in two or more layers, there is an advantage that the decay heat of a large number of post-use nuclear fuel assemblies 200 arranged above and below can be removed simultaneously using one heat pipe module 100.

That is, in some cases, the post-use nuclear fuel assemblies 200 are loaded on the two layers 200a and 200b in the storage tank 11 as shown in FIG. 5 in order to increase the storage density. Although not shown, it is a matter of course that the used nuclear fuel assemblies 200a and 200b arranged above and below are respectively inserted into insertion holes of racks stacked vertically.

As described above, both ends of each guide tube 251, 252, 253, 254, 255 of the post-use nuclear fuel assembly 200 are open. Therefore, when the post-use nuclear fuel assemblies 200 are stacked on the two layers 200a and 200b and are accurately aligned vertically, the branch pipes 111, 112, 113, 114, and 115 of one heat pipe module 100 are assembled into the upper assembly. The corresponding guide tube of the body 200a can be inserted into the corresponding guide tube of the lower assembly 200b.

In this way, the decay heat generated from the two post-use nuclear fuel assemblies 200a and 200b can be simultaneously removed using one heat pipe module 100, thereby reducing the number of heat pipe modules 100 used. There is an advantage that the structure of the wet passive cooling system 300 can be simplified.

In the drawing, only the case where the post-use nuclear fuel assembly 200 is loaded on two layers 200a and 200b is shown, but it is needless to say that such a method can also be applied when loaded on three or more layers. It is.

Referring to FIG. 5, the air cooling unit 17 may be installed on the outer side or the upper side of the shielding wall 18 of the storage water tank 11 and may have a chimney shape. For example, the air cooling unit 17 may include a vertical pipe body through which air can flow, and an air inlet and an air outlet formed at the lower end and the upper end of the pipe body, respectively. In this case, the heat pipe module 100 is installed so as to penetrate the side wall or the ceiling of the shielding wall 18, and the condensing part 130 of the heat pipe module 100 is positioned inside the tube.

An airtight member for preventing the outflow of radioactive material can be installed in a portion where the heat pipe module 100 penetrates in the side wall or ceiling of the shielding wall 181.

Although not shown, the wet passive cooling system 300 according to the embodiment of the present invention includes a real-time monitoring system including a sensor that detects the temperature, water level, flow rate, and the like of the cooling water 12, a sensor that detects a surface radiation dose, and the like. It is preferably configured to work together.

On the other hand, a refrigerant such as ammonia, ethanol, methanol, water, or chlorofluorocarbon is sealed inside the pipe body constituting the heat pipe module 100. A wick provided as a path through which the refrigerant condensed in the condensing unit 130 returns to the vaporizing unit 110 by capillary action may be formed on the inner wall of the tube body. However, if the condensation unit 130 is positioned above the vaporization unit 110 when the heat pipe module 100 is installed, the condensed fluid can be returned to the vaporization unit 110 by gravity. In such a case, the internal wick Can be omitted.

For example, in the wet passive cooling system 300 shown in FIG. 5, since the condensing unit 130 is located at the upper part of the vaporizing unit 110, the refrigerant can be returned by gravity, and thus a wick is formed inside the heat pipe module 100. You don't have to. Of course, the heat pipe module 100 provided with the wick can also be used. The heat transfer characteristics of the heat pipe module 100 can vary depending on the type of refrigerant, the internal compressor, the wick structure, and the like. Therefore, an appropriate refrigerant, internal pressure, wick structure, and the like can be selected according to the installation environment.

Further, in this specification, in the heat pipe module 100, the portion inserted into the post-use nuclear fuel assembly 200 is the vaporization unit 110, the portion where the radiation fins 150 are attached is the condensation unit 130, the vaporization unit 110 and the condensation unit 130, The part which connects is indicated as the connecting part 120. However, it should be understood that such names are for convenience of explanation. For example, since the connecting part 120 and the condensing part 130 are continuous tubes, the boundary is not clearly divided, and the refrigerant is vaporized by heat exchange with the cooling water 12 at the connecting part 120 immersed in the cooling water 12. This is because the refrigerant can be condensed by heat exchange with the atmosphere at the connecting portion 120 exposed to the outside of the cooling water 12.

The wet passive cooling system 300 according to the first embodiment of the present invention having the above-described configuration is used for the active cooling and the post-use nuclear fuel assembly 200 for forcibly circulating and cooling the cooling water 12 using a pump during normal operation. Passive cooling through the inserted heat pipe module 100 is performed at the same time, and through this, the cooling efficiency can be greatly improved compared to the conventional case.

In particular, heat pipe modules inserted into the guide tubes 251, 252, 253, 254, and 255 of the post-use nuclear fuel assembly 200 even when a complete power failure occurs inside and outside the nuclear power plant and active cooling by a pump is not possible Since each of the 100 branch pipes 111, 112, 113, 114, 115 continuously absorbs and removes the decay heat of the fuel rod 210, a serious accident can be prevented.

On the other hand, the wet passive cooling system 300 according to the first embodiment of the present invention having the above-described configuration can be implemented by being modified or modified in various forms.

For example, it is most preferable that the number of branch pipes constituting the vaporization unit 110 of the heat pipe module 100 is the same as the number of guide pipes 251, 252, 253, 254, and 255 provided in the post-use nuclear fuel assembly 200. However, it is not necessarily limited to this.

That is, the number of branch pipes constituting the vaporization unit 110 of the heat pipe module 100 may be smaller than the number of guide pipes 251, 252, 253, 254, 255 provided in the post-use nuclear fuel assembly 200. However, of course, the number of branch pipes must be two or more.

Further, the guide tubes provided in the post-use nuclear fuel assembly 200 are not limited to the control rod guide tubes 251, 252, 253, 254 and the measuring instrument guide tube 255, but may include other types of guide tubes. Further, the number of guide tubes is not limited to that shown in the figure.

As another example, like the wet passive cooling system 300a of FIG. 8, the guide pipes 251, 252, and the like pipes 111, 112, 113, 114, 115 of the heat pipe module 100 are used from the lower end of the nuclear fuel assembly 200 after use. 253, 254, 255 can also be inserted.

Also in this case, when the post-use nuclear fuel assemblies 200 are stacked in two layers, the branch pipes 111, 112, 113, 114, 115 of one heat pipe module 100 are guided to corresponding guides of the lower assembly 200b. The tube can be inserted to the inside of the corresponding guide tube of the upper assembly 200a. Also in this case, it is preferable that the condensing part 130 of the heat pipe module 100 is located inside the air cooling part 17.

As another example, when the post-use nuclear fuel assemblies 200 are stacked in two layers as in the wet passive cooling system 300b of FIG. 9, the guide tubes of the upper assembly 200a and the lower assemblies 200b Different heat pipe modules 100a and 100b can be inserted into the guide tubes.

As still another example, as shown in the wet passive cooling system 300c of FIG. 10, an elevating unit 500 that can elevate and lower the entire heat pipe module 100 can be included. When the connecting part 12 of each heat pipe module 100 is coupled to the elevating part 500, the entire heat pipe module 100 inside the system can be raised and lowered simultaneously by the elevating movement of the elevating part 500. In this way, the heat pipe module 100 Installation work can be made easier.

As shown in FIG. 11, the periphery of the elevating unit 500 can be coupled to the upper end of the shielding wall 18 by means of a bellows 520 or the like. In this way, even if the elevating unit 500 moves up and down, The isolated state of the upper space and the external space can be maintained. Moreover, the pipe body which comprises the air cooling part 17 can be couple | bonded with the raising / lowering part 500, and when the raising / lowering part 500 raises / lowers, it can also comprise so that the air cooling part 17 may raise / lower together.

Second Embodiment A second embodiment of the present invention relates to a dry-type post-use nuclear fuel passive cooling system (hereinafter referred to as “dry passive cooling system”).

As shown in the schematic configuration diagram of FIG. 12, the dry passive cooling system 400 according to the second embodiment of the present invention includes an inner container 420 in which the post-use nuclear fuel assembly 200 is accommodated, and an outer container 420 outside the inner container 420. It includes an outer container 410 that surrounds the inner container 420 with a certain distance from the side surface, and an air flow path 430 formed between the inner container 420 and the outer container 410.

The air flow path 430 communicates with the outside through an inlet 432 and an outlet 434 formed in the lower and upper portions of the side wall of the outer container 410, respectively. Therefore, the air flowing in through the lower inlet 432 absorbs the heat generated from the inner container 420, and after being heated and raised, is discharged outside through the outlet 434.

In particular, the dry passive cooling system 400 according to the second embodiment of the present invention is installed through the inner container 420, and the heat pipe module 100 in which the vaporization unit 110 is inserted into the nuclear fuel assembly 200 after use. including.

The vaporization unit 110 of the heat pipe module 100 includes a large number of branch pipes 111, 112, 113, 114, 115, and each branch pipe 111, 112, 113, 114, 115 corresponds to the corresponding guide pipe 251 of the post-use nuclear fuel assembly 200. , 252, 253, 254, and 255, respectively, is the same as that of the first embodiment.

Although the condensing part 130 of the heat pipe module 100 is located inside the air flow path 430 and the drawing shows that the condensing part 130 is located near the discharge port 434, the condensing part 130 is located near the inlet 432 having a lower air temperature. It can also be installed. Further, the condensing unit 130 can be installed outside the external container 410.

The inner container 420 is preferably made of a metal material that can be easily kept airtight, and the outer container 410 can be made of a metal or a concrete material. In particular, it is preferable to install an airtight member capable of preventing the outflow of radioactive material at a portion where the heat pipe module 100 penetrates in the inner container 420.

On the other hand, although not shown, the dry passive cooling system 400 according to the second embodiment of the present invention includes a temperature sensor that detects the temperature of the inner container 420 and / or the outer container 410, and a radiation dose around the inner container 420. It is preferable to be configured to work with a real-time monitoring system including a sensor for detecting

According to the dry passive cooling system 400 according to the second embodiment of the present invention, when the inner container 420 is heated by the decay heat of the post-use nuclear fuel assembly 200 stored in the inner container 420, the interior of the air flow path 430 is increased. Natural convection occurs and heat on the wall surface of the inner container 420 is removed. At the same time, the high-temperature decay heat is more directly absorbed and discharged through the branch pipes 111, 112, 113, 114, 115 of the heat pipe module 100 installed close to the fuel rod, and thus the inner container 420 Can be more effectively suppressed, and through this, the safety of the dry storage facility can be greatly improved.

The dry passive cooling system 400 according to the second embodiment of the present invention can be implemented with various modifications or modifications. For example, as described in connection with the first embodiment, when two or more post-use nuclear fuel assemblies 200 are loaded in the inner container 420, each branch pipe of one heat pipe module 100 is used. 111, 112, 113, 114, 115 can be simultaneously inserted into corresponding guide tubes of the post-use nuclear fuel assembly 200 having two or more layers.

Further, the branch pipes 111, 112, 113, 114, and 115 of the heat pipe module 100 can be inserted from the lower end of the used nuclear fuel assembly 200. When two or more layers of post-use nuclear fuel assemblies 200 are loaded, each branch pipe of the first heat pipe module 100a is inserted into each guide tube of the upper assembly 200a from the upper end, and the lower assembly 200b. Each branch pipe of the second heat pipe module 100b can be inserted into each guide pipe from the lower end.

Moreover, the raising / lowering part which raises / lowers the heat pipe module 100 can be included. Further, the number of branch pipes of the heat pipe module 100 may be smaller than the number of guide pipes of the post-use nuclear fuel assembly 200.

As described above, the present invention can be implemented by being modified or modified in various forms in a specific application process, and the modified or modified embodiments are also disclosed in the scope of claims described later. Of course, the technical scope of the present invention belongs to the scope of the right of the present invention.

DESCRIPTION OF SYMBOLS 11 Storage water tank 12 Cooling water 15 Cooling water supply pipe 16 Cooling water discharge pipe 17 Air cooling part 18 Shielding wall 20 Storage stand 100 Heat pipe module 110 Vaporization part 111,112,113,114,115 1st thru | or 5th branch pipe 120 connection Unit 130 condensing unit 150 radiating fin 200 post-use nuclear fuel assembly 210 fuel rod 220 support grid 230 upper support 240 lower support 251, 252, 253, 254 first to fourth control rod guide tube 255 instrument guide tube 300 Wet passive cooling system 400 Dry passive cooling system 410 External container 420 Internal container 430 Air flow path 432 Inlet 434 Outlet 500 Lifting unit 520 Bellows

Claims (8)

A containment tank filled with cooling water;
A post-use nuclear fuel assembly comprising a number of fuel rods and a number of guide tubes open at the top and bottom, and stored in the storage tank;
A plurality of branch pipes, and a heat pipe module including a condenser section communicating with the multiple branch pipes, wherein the multiple branch pipes are respectively inserted into the multiple guide pipes. A passive cooling system for post-use nuclear fuel assemblies. The upper space of the storage tank is surrounded by a shielding wall, and the condensing part of the heat pipe module is located inside an air cooling part provided outside the shielding wall. Passive cooling system for nuclear fuel assemblies after use. An elevating part installed at an upper end of the shielding wall and supporting each of the plurality of heat pipe modules;
3. The post-use nuclear fuel assembly according to claim 2, further comprising a bellows connecting a peripheral portion of the elevating unit and an upper end of the shielding wall, wherein the air cooling unit is coupled to the elevating unit. Passive cooling system. An inner container,
An outer container surrounding the inner container with an air flow path in between;
An inlet and an outlet formed in the outer container and communicating with the air flow path;
A post-use nuclear fuel assembly comprising a number of fuel rods and a number of guide tubes open at the top and bottom, and stored in the inner vessel;
A heat pipe module including a vaporization section composed of a number of branch pipes and a condenser section communicating with the number of branch pipes, wherein the number of branch pipes are respectively inserted into the number of guide pipes. A passive cooling system for nuclear fuel assemblies after use. The passive cooling system for a post-use nuclear fuel assembly according to claim 4, wherein the condensing part of the heat pipe module is located inside the air flow path. 5. The plurality of guide tubes include a control rod guide tube and a measuring instrument guide tube, and the number of the plurality of branch tubes is the same as the number of the plurality of guide tubes. A passive cooling system for post-use nuclear fuel assemblies as described in. The post-use nuclear fuel assembly includes an upper assembly and a lower assembly stacked one above the other, and the plurality of branch pipes are respectively a guide tube corresponding to the upper assembly and a corresponding guide of the lower assembly. The passive cooling system for a post-use nuclear fuel assembly according to claim 1 or 4, wherein the system is inserted together in a tube. 5. The passive cooling system for a post-use nuclear fuel assembly according to claim 1, wherein the plurality of branch pipes are respectively inserted into the plurality of guide pipes from lower ends of the post-use nuclear fuel assembly.

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