JP4746911B2 - Method for constructing fast reactor and fast reactor facility - Google Patents

Description

  The present invention relates to a fast reactor having passive safety and a construction method of a fast reactor facility equipped with the fast reactor.

  Faster reactors are required to have a higher level of safety, and passive safety has been studied to converge the effects of disturbances without using dynamic equipment. For example, in the fast reactor disclosed in Japanese Patent Laid-Open No. 9-72980, when an abnormality such as loss of coolant flow occurs, the volume of the gas space is expanded by the outflow of coolant to promote neutron streaming from the core. The negative reactivity is inserted into the furnace.

  In a fast reactor such as Monju, fuel formed in a pellet form is filled and sealed in a fuel cladding tube to form a fuel element, and a number of fuel elements are inserted into a trumpet tube to constitute a fuel assembly. An entrance nozzle is provided at the lower part of the trumpet tube, and liquid sodium as a coolant flows into the trumpet tube through the orifice hole of the entrance nozzle, and removes heat while flowing between the fuel elements and flows out upward. That is, the outside of each fuel element is cooled with liquid sodium.

JP-A-9-72980

  However, it is important to provide multiple means with different principles and ideas for the safety of fast reactors, and further technical development is required for passive safety.

  In addition, the fast reactor such as Monju uses pellet fuel and the outside of the fuel element is cooled by liquid sodium. However, this structure is not optimal for all fast reactors. Sometimes it is better to cool the inside as well as the outside.

  Furthermore, in order to put these fast reactors into practical use, it is necessary to construct a fast reactor facility economically.

  An object of this invention is to provide the fast reactor excellent in passive safety. Another object of the present invention is to provide a fast reactor with excellent cooling performance. Furthermore, an object of the present invention is to provide a method for constructing a fast reactor facility that is excellent in economic efficiency.

To achieve this object, a fast reactor according to claim 1 includes a plurality of fuel elements having metal fuel and a liquid metal coolant for cooling the fuel elements (excluding liquid sodium). The vessel is installed in a pool that stores a quantity of water that can remove the decay heat of the core and maintain the integrity of the core when the operation is stopped , and liquid metal cooling is performed separately from the pool water during operation. A secondary cooling system for removing the heat of the material is provided .

  Therefore, the metal fuel constituting the core is cooled by the liquid metal coolant as the primary coolant. The heat of the liquid metal coolant is transferred to, for example, the secondary coolant and removed. If for some reason the heat of the liquid metal coolant can no longer be removed by the secondary coolant, the liquid metal coolant will become hot and the reactor vessel temperature will rise, but the water stored in the pool will The furnace vessel can be cooled. Also, even if liquid metal coolant (except liquid sodium) comes into contact with water in the pool, it will not react violently.

  According to a second aspect of the present invention, in the fast reactor, the fuel element includes a fuel element container whose inside is sealed, and a cooling pipe penetrating the inside of the fuel element container in the vertical direction. The inner surface of the container and the outer peripheral surface of the cooling pipe are in contact with each other, and the outer surface of the fuel element container and the inner peripheral surface of the cooling pipe are cooled by the liquid metal coolant. Therefore, the heat generated in the metal fuel is transferred to the fuel element container and the cooling pipe, and is removed by the liquid metal coolant flowing outside the fuel element container and in the cooling pipe.

  The fast reactor according to claim 3 is provided with a coolant driving mechanism for each fuel element for forcibly circulating the liquid metal coolant in the cooling pipe. Therefore, the liquid metal coolant in the reactor vessel is circulated not only by natural convection but also by the driving force generated by the coolant driving mechanism. Since the coolant driving mechanism is provided for each fuel element, the flow rate of the liquid metal coolant can be adjusted for each fuel element.

  In the fast reactor according to claim 4, the inside of the pool is pressurized. Therefore, even if a crack or the like occurs in the reactor vessel, it is possible to prevent leakage of the liquid metal coolant.

Further, in the method for constructing a fast reactor facility according to claim 5, the equipment of the reactor facility is removed from the reactor containment vessel of the existing reactor facility, The reactor vessel according to any one of claims 1 to 5 is installed, and an amount of water that can remove the decay heat of the core and maintain the integrity of the core when the operation is stopped is stored. 5 is used in the pool according to any one of claims 4 to 4, and the secondary cooling system according to any one of claims 1 to 4 is installed to provide the high speed according to any one of claims 1 to 4. A facility equipped with a furnace will be constructed.

  For example, in a plant equipped with a light water reactor, a reactor containment vessel is installed in the reactor building, and the reactor vessel is accommodated therein. The reactor containment vessel was originally intended for containment of radioactive materials and can store water inside. By diverting this reactor containment vessel as a pool, a facility equipped with the fast reactor according to any one of claims 1 to 4 can be constructed using an existing reactor facility.

In the fast reactor according to claim 1, a reactor vessel containing a plurality of fuel elements having a metal fuel and a liquid metal coolant (except for liquid sodium) for cooling the fuel elements is provided at the time of shutdown. A secondary system that removes heat from the liquid metal coolant in a separate system from the pool water during operation , while installing in a pool that stores a quantity of water that can remove decay heat and maintain the integrity of the core Since the cooling system is provided, even if the heat of the liquid metal coolant as the primary coolant cannot be removed by the secondary coolant of the secondary cooling system, the reactor vessel can be cooled by the pool water . For this reason, the passive safety of the fast reactor can be further improved. Also, the liquid metal coolant (except liquid sodium) does not react violently with water, and it is safe even if the liquid metal coolant contacts the water in the pool.

  Further, in the fast reactor according to claim 2, the fuel element includes a fuel element container sealed inside and a cooling pipe penetrating the inside of the fuel element container in the vertical direction, and the metal fuel is the fuel element at least during operation. The inner surface of the container and the outer peripheral surface of the cooling pipe are in contact with each other, and the liquid metal coolant cools the outer surface of the fuel element container and the inner peripheral surface of the cooling pipe. It is transferred to the cooling pipe and removed by liquid metal coolant flowing outside the fuel element container and in the cooling pipe. That is, the liquid metal coolant can be circulated inside and outside the metal fuel, and the metal fuel can be cooled from both the inside and outside. For this reason, cooling performance can be improved. Moreover, even if cooling from either the inner side or the outer side becomes impossible, the cooling can be performed from the other side, so that safety can be further improved.

  Moreover, in the fast reactor according to claim 3, since the coolant driving mechanism for forcibly circulating the liquid metal coolant in the cooling pipe is provided for each fuel element, the circulation of the liquid metal coolant is further improved. The cooling performance can be further improved. Further, the flow rate of the liquid metal coolant can be adjusted for each fuel element. For this reason, the core design is facilitated, the uranium resource as the fuel can be effectively used, and the life of the core can be further extended.

  In the fast reactor according to claim 4, since the inside of the pool is pressurized, it is possible to prevent the liquid metal coolant from leaking even if a crack or the like occurs in the reactor vessel. For this reason, loss of the liquid metal coolant can be prevented, and deterioration of the cooling performance can be prevented.

Further, in the method for constructing a fast reactor facility according to claim 5, after the equipment of the reactor facility is removed from the reactor containment vessel of the existing reactor facility, The reactor containment vessel according to any one of claims 1 to 4, wherein the reactor containment vessel according to any one of claims 1 to 4 is installed, wherein an amount of water that can remove the decay heat of the core and maintain the integrity of the core when the operation is stopped is stored. The fast reactor according to any one of claims 1 to 4, wherein the fast cooling system is diverted to the pool according to any one of claims 1 to 4 and the secondary cooling system according to any one of claims 1 to 4 is installed. Therefore, a fast reactor facility can be constructed using an existing nuclear reactor facility. For this reason, the cost required for the construction of the fast reactor facility can be reduced. In addition, since some of the existing nuclear reactor facilities can be used effectively, waste can be reduced by that much, which is excellent in terms of the environment. Furthermore, since the old nuclear reactor facility can be reused, the nuclear facility can be used effectively, for example, the burden of radiation management accompanying the decommissioning of the nuclear reactor can be reduced.

  Hereinafter, the configuration of the present invention will be described in detail based on the best mode shown in the drawings.

  FIG. 1 shows an example of an embodiment of a fast reactor to which the present invention is applied. The fast reactor 1 is a reactor in which a reactor vessel 5 containing a fuel element 3 having a metal fuel 2 and a liquid metal coolant (except for liquid sodium) 4 for cooling the fuel element 3 is installed in a pool 6. It is. A large number of fuel elements 3 are arranged in the nuclear reactor vessel 5 with a slight gap 7 therebetween, thereby forming a core 27. Although two fuel elements 3 are shown in FIG. 1, a large number of fuel elements 3 are actually provided. A cylindrical body 8 is provided around the assembly of fuel elements 3.

  A cross section of the fuel element 3 is shown in FIG. The fuel element 3 includes a fuel element container 9 whose inside is sealed, and a cooling pipe 10 penetrating the fuel element container 9 in the vertical direction. At least during operation, the metal fuel 2 is disposed on the inner surface of the fuel element container 9 and The outer peripheral surface of the cooling pipe 10 is in contact with the outer peripheral surface of the fuel element container 9 and the inner peripheral surface of the cooling pipe 10 by the liquid metal coolant 4. That is, when the fast reactor 1 is operated and the metal fuel 2 becomes high temperature, the metal fuel 2 expands. However, at least when the metal fuel 2 expands, the metal fuel 2 sufficiently contacts the fuel element container 9 and the cooling pipe 10, and the metal fuel 2 The generated heat can be satisfactorily transmitted to the fuel element container 9 and the cooling pipe 10.

  As the liquid metal coolant 4, a liquid metal other than liquid sodium that reacts violently with water, such as liquid lead-bismuth, is used. However, a liquid metal other than liquid lead-bismuth, such as mercury or lead, may be used as the liquid metal coolant 4.

  The fuel element container 9 is, for example, a stainless steel box. The cooling pipe 10 is, for example, a stainless steel pipe. However, these materials are not limited to stainless steel, and materials other than stainless steel may be adopted. A plurality of cooling pipes 10 penetrates the fuel element container 9 in the vertical direction.

  The metal fuel 2 is a metal fuel such as U-Zr. However, it is not limited to U-Zr, and other uranium alloys, plutonium alloys, etc. may be used, and metal uranium, metal plutonium, etc. may be used. The metal fuel 2 has a particle shape, for example, and is filled in the fuel element container 9. The fuel element container 9 is filled with the metal fuel 2 at a filling rate (smear density) of about 50 to 80%, for example, and the gap between the metal fuels 2 is filled with an inert gas such as He. Further, the upper space of the metal fuel 2 is an inert gas reservoir 11 such as He. Since the particulate metal fuel 2 is filled, the metal fuel 2 can move in the fuel element container 9, and volume expansion during operation can be released. Gases such as krypton and xenon generated by the fission of the metal fuel 2 are stored in the inert gas reservoir 11. The heat generated in the metal fuel 2 is directly transmitted to the fuel element container 9 and the cooling pipe 10 by contact, but is also transmitted by an inert gas filled in the gap.

  In practice, for example, as shown in FIG. 3, the fuel element 3 filled with the above-described metal fuel 2 is disposed at the center 27a of the core 27, and the fuel element 3 filled with blanket fuel is disposed around the periphery 27b. , Fast neutron leakage prevention and plutonium breeding.

  The fuel elements 3 are arranged, for example, with an interval of 10 mm (interval of fuel elements, pitch interval is 157 mm). The size of the fuel element 3 is, for example, 0.152 m × 0.152 m in cross section and 2 m in height. One fuel element 3 is provided with, for example, 100 cooling pipes 10 (only 25 are shown in FIG. 2). The inner diameter of the cooling pipe 10 is 11 mm, for example. The cooling pipes 10 are arranged with an interval of 15 mm, for example. However, these numerical values are examples, and are not limited to these numerical values. Design appropriately according to the required cooling capacity and output.

  In the present embodiment, a coolant driving mechanism 12 that forcibly circulates the liquid metal coolant 4 in the cooling pipe 10 is provided for each fuel element 3. The coolant driving mechanism 12 is, for example, an electromagnetic pump (EMP). The coolant driving mechanism 12 is provided at the lower end opening portion of the fuel element container 9, and sucks the liquid metal coolant 4 from under the fuel element 3 and discharges it into the cooling pipe 10. The discharge amount can be adjusted by changing the energization amount for each coolant driving mechanism 12.

  An upper portion in the reactor vessel 5 is an inert gas reservoir 13 filled with an inert gas such as He, nitrogen, or argon. The volume fluctuation accompanying the temperature change of the liquid metal coolant 4 can be absorbed by changing the volume of the inert gas reservoir 13.

  A steam generator 14 is installed in the reactor vessel 5. The steam generator 14 has, for example, a cylindrical shape, is disposed at a position close to the liquid level 4 a of the liquid metal coolant 4, and is attached to the inner peripheral surface of the reactor vessel 5. Flow paths 16 and 17 for circulating the secondary coolant 15 are connected to the steam generator 14. The secondary coolant 15 is, for example, water / steam. The steam generator 14 performs heat exchange between the liquid metal coolant 4 as the primary coolant and the water as the secondary coolant 15 to generate steam.

  On the upper surface of the reactor vessel 5, a drive mechanism 18 that drives a control rod and a safety rod is installed. In FIG. 1, the control rod and the safety rod are collectively shown as a rod 19, but actually, a plurality of control rods and a plurality of safety rods are installed, and the position is controlled by the drive mechanism 18. Control rods and safety rods are inserted into the gaps 7 between the fuel elements 3. However, a pipe penetrating the fuel element container 9 similar to the cooling pipe 10 may be provided, and a control rod or a safety rod may be inserted into the pipe.

  The reactor vessel 5 is installed in the pool 6. The pool 6 has a sufficient amount of water that can remove the decay heat of the core 27 and maintain the soundness of the core 27 even if cooling by the secondary coolant 15 becomes impossible at the time of shutdown. Is stored. A steam explosion preventing agent such as ethylene glycol is added to the water. The inside of the pool 6 is sealed with a lid 20 and pressurized. For example, the pressure is about 10 to several tens of atmospheres. The temperature of the water in the pool 6 is room temperature, for example. The lid 20 also has a function of confining radioactive materials.

  Next, the operation of the fast reactor 1 will be described.

  The liquid metal coolant 4 that is the primary coolant rises to a high temperature while cooling the core 27, and is cooled by the steam generator 14 and descends. Then, it is sucked into the coolant driving mechanism 12 and discharged toward the core 27. That is, the core 27 is cooled while circulating vertically inside and outside the cylindrical body 8. At this time, the liquid metal coolant 4 flows through the gap 7 between the cooling pipe 10 provided in each fuel element 3 and each fuel element 3 to cool the metal fuel 2 from both the inside and the outside. The fuel 2 can be cooled well and the cooling performance is excellent.

  On the other hand, the secondary coolant (water) 15 that has flowed into the steam generator 14 from the inlet-side channel 16 is heated by the liquid metal coolant 4 to become steam. And it flows out from the exit side flow path 17, for example, drives the steam turbine of the generator which is not shown in figure, and generates electric power. Thereafter, the steam is returned to a liquid state by a condenser (not shown) and circulated to the steam generator 14. Thus, during normal operation of the fast reactor 1, heat generated in the core 27 is external to the fast reactor 1 by the primary cooling system that circulates the liquid metal coolant 4 and the secondary cooling system that circulates the secondary coolant 15. The integrity of the core 27 is maintained.

  In the fast reactor 1, since the coolant driving mechanism 12 is provided for each fuel element 3, the flow rate of the liquid metal coolant 4 can be adjusted for each fuel element 3. Here, the power distribution of the core 27 changes with operation, but if the flow rate of the liquid metal coolant 4 cannot be partially adjusted, it is necessary to keep the power distribution of the core 27 substantially constant. For this reason, if the change in the power distribution becomes large to some extent, it is necessary to temporarily stop the reactor and change the position of the fuel, or to replace the fuel, so that the operation cannot be continued for a long time. In contrast, in the present invention, since the flow rate of the liquid metal coolant 4 can be adjusted for each fuel element 3, even if the change in the power distribution of the core 27 becomes large, the liquid metal cooling is performed according to this change. By adjusting the flow rate of the material 4, the operation can be continued as it is without changing the position of the fuel or replacing the fuel. For this reason, a longer-life core 27 can be configured.

  In addition, since the flow rate of the liquid metal coolant 4 can be adjusted for each fuel element 3, the core design is reduced and the core design is facilitated. For this reason, it is possible to design a core having a high breeding performance of the core 27, and further to extend the life of the core 27 and to effectively use uranium resources.

  When a malfunction occurs in the cooling system and the operation of the fast reactor 1 is stopped, the decay heat of the core 27 is removed as follows. When the coolant driving mechanism 12 is operated, the liquid metal coolant 4 is forcibly circulated by the coolant driving mechanism 12. On the other hand, when the coolant driving mechanism 12 does not operate, the liquid metal coolant 4 circulates by natural convection. Therefore, in any case, the core 27 can be cooled by circulating the liquid metal coolant 4, and the passive safety is excellent. At this time, since the liquid metal coolant 4 flows through the gap 7 between the cooling pipe 10 of each fuel element 3 and each fuel element 3 to cool the metal fuel 2 from both the inside and outside, the cooling performance is excellent. Yes. Moreover, even if one of the cooling pipe 10 and the gap 7 is blocked, for example, it becomes difficult to distribute the liquid metal coolant 4, the liquid metal coolant 4 can be distributed to the other. Therefore, cooling of the core 27 can be ensured. For this reason, it is excellent in passive safety.

  Even if the heat of the liquid metal coolant 4 cannot be transported outside the fast reactor 1 by the secondary coolant 15, the reactor vessel 5 is installed in the pool 6. The reactor vessel 5 can be cooled. Since a sufficient amount of water is stored in the pool 6 to remove the decay heat of the core 27, the liquid metal coolant 4 cooled by the water in the pool 6 is forcibly circulated by the coolant driving mechanism 12. By this, or by the natural convection of the liquid metal coolant 4, the decay heat of the core 27 can be removed and the soundness can be maintained. For this reason, it is excellent in passive safety.

  Furthermore, even if a crack or the like occurs in the reactor vessel 5, the inside of the pool 6 is pressurized, and the water pressure corresponding to the depth acts on the reactor vessel 5 in water. It is difficult for the metal coolant 4 to leak out of the reactor vessel 5. For this reason, loss of the liquid metal coolant 4 can be prevented, and generation of a vapor explosion due to contact between the high-temperature liquid metal coolant 4 and water can be prevented. For these reasons, it is excellent in safety. Further, for example, liquid lead-bismuth is adopted as the liquid metal coolant 4, and even if the liquid metal coolant 4 comes into contact with water, it does not react violently, and this point is also excellent in safety. .

  The drive mechanism 18 for driving the control rod and the safety rod is installed on the upper surface of the reactor vessel 5 and moves the control rod and the safety rod within the pressurized area in the pool 6. That is, since the control rod and the safety rod are not configured to be inserted into the pool 6 from the outside of the pool 6, the control rod and the safety rod are not moved by the pressurization in the pool 6.

  Although the facility 21 including the fast reactor 1 of the present invention may be newly constructed, the existing nuclear reactor facility 22 may be modified. That is, after the equipment of the reactor facility 22 is removed from the reactor containment vessel 23 of the existing reactor facility 22, the reactor vessel 5 is installed in the reactor containment vessel 23 and water is stored, and the reactor is stored. The fast reactor facility 21 can also be constructed by diverting the container 23 to the pool 6.

  In FIG. 4, an example of the construction method of the fast reactor facility 21 is shown. FIG. 4A shows an existing BWR (boiling light water reactor) plant 22, for example. In the BWR plant 22, a reactor containment vessel 23 is installed in the reactor building 24, and a reactor vessel 25 is installed therein. The BWR plant 22 can be modified to the fast reactor plant 21 by removing the reactor vessel 25 and other equipment from the reactor containment vessel 23, installing the reactor vessel 5 of the fast reactor 1 and storing water. (FIG. 4B). In the BWR plant 22, water is stored in the reactor containment vessel 23 and the reactor vessel 25 is submerged when the fuel is changed, so that the reactor containment vessel 23 can be diverted to the pool 6.

  For example, in the 360,000 KWe class BWR plant 22, the diameter of the internal space of the reactor building 24 is 38 m, the diameter of the internal space of the reactor containment vessel 23 is 17 m, and the diameter of the reactor vessel 25 is 9 m. In the fast reactor plant 21 of about 400,000 KWe class, the core 27 has a diameter of about 3.5 m and the reactor vessel 5 has a diameter of about 6 m, so that it can be installed in the reactor containment vessel 23. That is, the 360,000 KWe class BWR plant 22 can be remodeled to construct an about 400,000 KWe class fast reactor plant 21 with an output increased by 10%. In the vicinity of the reactor containment vessel 23, there is a pool 28 for temporarily storing spent fuel, and this pool 28 can be used as it is.

  Thus, since the latest fast reactor facility 21 can be constructed using the existing nuclear reactor facility 22, the construction of the fast reactor facility 21 is facilitated, and the construction cost can be reduced. In addition, since a part of the existing nuclear reactor facility 22 can be used effectively, waste can be reduced accordingly. Furthermore, the maintenance and management burden of the high-aged nuclear reactor will be eliminated by remodeling the high-aged light water nuclear power plant that has been built for many years to the latest fast reactor facility 21.

  The above-described embodiment is an example of a preferred embodiment of the present invention, but is not limited thereto, and various modifications can be made without departing from the scope of the present invention.

  For example, in the fast reactor 1 described above, the fuel metal container 2 is filled with the particle-shaped metal fuel 2. For example, as shown in FIG. 5, a metal tube that can be deformed between the particle-shaped metal fuel 2. 26 may be inserted, and the metal tube 26 may be deformed in accordance with the expansion / contraction associated with the temperature change of the metal fuel 2. The upper part of the metal tube 26 is opened to the inert gas reservoir 11. Further, the cross section of the metal tube 26 has an elliptical shape, for example.

  Further, instead of filling the metal fuel 2 in the form of particles, for example, the molten metal fuel 2 is poured into the fuel element container 9 to be cooled and solidified, and then a mechanical tool such as a drill is used. It is also possible to provide a gas hole.

  In the above description, the coolant driving mechanism 12 is provided for each fuel element 3 to forcibly circulate the liquid metal coolant 4. However, the coolant driving mechanism 12 is omitted and the liquid metal coolant 4 is naturally It may be convected.

  Furthermore, in the above description, the BWR plant is taken as an example of the existing nuclear reactor facility 22 and the BWR plant has been modified to the fast reactor plant 21, but the nuclear reactor facilities other than the BWR plant have been modified to the fast reactor plant 21. Of course, it may be.

  An experiment was conducted to confirm the life of the core 27 of the fast reactor 1 of the present invention. The core 27 shown in FIG. 3 was designed and its combustion characteristics were calculated. The metallic fuel 2 of the fuel element 3 to be installed within a radius of 1.2 m (region indicated by reference numeral 27a) from the center of the core 27 is a U-10% Zr alloy (Zr is 10%) using 10% enriched uranium. %, U is 90%) and the surrounding blanket (region indicated by reference numeral 27b) is a U-10% Zr alloy using 0.2% depleted uranium. The blanket fuel has a radius of 1.6 m and the core height is about 2 m.

  The result of the experiment is shown in FIG. Even when the burnup exceeded 200 GW · d / T (gigawatt day / ton), a reactivity k of 1.00 or more could be secured. In a typical light water reactor, a reactivity k of 1.00 or more can be secured at about 50 GW · d / T. As is apparent from this result, it was confirmed that the core 27 of the fast reactor 1 of the present invention has a long life.

It is a schematic block diagram which shows an example of embodiment of the fast reactor to which this invention is applied. It is sectional drawing of the fuel element of the fast reactor of FIG. It is a conceptual diagram of the core of the fast reactor of FIG. An example of embodiment of the construction method of the fast reactor facility to which this invention is applied is shown, (A) is a schematic block diagram of the existing BWR plant before remodeling, (B) is a schematic block diagram of the fast reactor plant after remodeling. is there. It is a figure which shows a mode that the metal tube was provided between the metal fuels. It is a graph which shows the combustion characteristic of the core of the fast reactor of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fast reactor 2 Metal fuel 3 Fuel element 4 Liquid metal coolant 5 Reactor vessel 6 Pool 9 Fuel element vessel 10 Cooling pipe 12 Coolant drive mechanism 23 Reactor containment vessel

Claims (5)

A reactor vessel containing a plurality of fuel elements having a metal fuel and a liquid metal coolant (excluding liquid sodium) for cooling the fuel elements is removed from the reactor core by removing the decay heat of the core when the reactor is shut down. Installed in a pool that stores a quantity of water that can maintain soundness, and has a secondary cooling system that removes the heat of the liquid metal coolant separately from the water in the pool during operation. Fast reactor characterized by   The fuel element includes a fuel element container sealed inside and a cooling pipe penetrating the fuel element container in the vertical direction, and at least during operation, the metal fuel contains the inner surface of the fuel element container and the cooling element. The fast reactor according to claim 1, wherein the fast reactor is in contact with an outer peripheral surface of the tube, and the liquid metal coolant cools the outer surface of the fuel element container and the inner peripheral surface of the cooling tube.   The fast reactor according to claim 2, wherein a coolant driving mechanism for forcibly circulating the liquid metal coolant in the cooling pipe is provided for each fuel element.   The fast reactor according to any one of claims 1 to 3, wherein the inside of the pool is pressurized. The reactor vessel according to any one of claims 1 to 4 is installed in the reactor containment vessel after the equipment of the reactor facility is removed from the reactor containment vessel of the existing reactor facility. The amount of water that can remove the decay heat of the core and maintain the integrity of the core when the operation is stopped is stored, and the reactor containment vessel is diverted to the pool according to any one of claims 1 to 4. And installing the secondary cooling system according to any one of claims 1 to 4 to construct a facility equipped with the fast reactor according to any one of claims 1 to 4. How to construct a fast reactor facility.

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