JP2020183892A - Reactor cooling device and nuclear power plant - Google Patents

Abstract

To provide a reactor cooling device that is capable of maintaining the cooling performance, even when a natural circulation passage is blocked in a passive cooling system utilizing natural convection.SOLUTION: A reactor cooling device includes: a natural circulation passage 45 of a cooling medium for cooling heat of a nuclear reactor; a backup pipe 50 connected to the natural circulation passage 45; and a turbomachine 52 provided in the backup pipe 50.SELECTED DRAWING: Figure 2

Description

The present invention relates to a nuclear reactor cooling system and a nuclear power plant.

As a technique relating to a passive cooling system for a nuclear reactor using natural convection, there is one described in Patent Document 1 below. According to this document, "In a liquid metal cooled reactor 10, ... a tubular heat collector 34 is installed between the guard vessel 19 and the silo 31. A downflow passage 35 between the heat collector 34 and the silo 31. Is formed, and an ascending flow passage 36 is formed between the heat collector 34 and the guard vessel 19. The descending flow passage 35 is an air introduction pipe as an intake passage which is buried under the ground surface and has an air introduction port 38. The upflow passage 36 is connected to the air discharge pipe 39 as an exhaust passage buried under the ground surface and provided with an air discharge port 40. These downflow passages 35 and upflow passages 35. 36, the air introduction pipe 37 and the air discharge pipe 39 constitute a cooling passage 33. "

Japanese Unexamined Patent Publication No. 2013-76675

However, in the above-mentioned passive cooling system for a nuclear reactor, if the cooling passage due to natural circulation is blocked for some reason, the amount of air circulation required to remove the heat generated in the core cannot be secured. , The cooling of the reactor becomes insufficient.

Therefore, an object of the present invention is to provide a nuclear reactor cooling device and a nuclear power plant capable of maintaining cooling performance even when a natural circulation passage in a passive cooling system using natural convection is blocked. ..

In order to solve the above problems, for example, the configuration described in the claims is adopted.
The present application includes a plurality of means for solving the above-mentioned problems. For example, a natural circulation passage of a cooling medium for cooling the heat of a nuclear reactor and an auxiliary pipe connected to the natural circulation passage. , A nuclear reactor cooling device provided with a turbomachinery provided in the auxiliary pipe.

According to the present invention, it is possible to provide a nuclear reactor cooling device and a nuclear power plant capable of maintaining cooling performance even when a natural circulation passage in a passive cooling system utilizing natural convection is blocked.
Issues, configurations and effects other than those described above will be clarified by the description of the embodiments on the following side.

It is a block diagram of the nuclear power plant which concerns on embodiment. It is a block diagram (the 1) of the reactor cooling apparatus which concerns on embodiment. It is a block diagram (No. 2) of the reactor cooling apparatus which concerns on embodiment. It is a block diagram (No. 3) of the reactor cooling apparatus which concerns on embodiment. It is a block diagram of the reactor cooling apparatus which concerns on the modification of embodiment.

Hereinafter, embodiments of the nuclear reactor cooling system and the nuclear power plant of the present invention will be described in detail with reference to the drawings. In the embodiments and modifications described below, the same components are designated by the same reference numerals, and duplicate description will be omitted.

≪Nuclear plant≫
FIG. 1 is a configuration diagram of a nuclear power plant 1 according to an embodiment, and is a configuration diagram when the present invention is applied to a nuclear power plant 1 having a tank-type fast breeder reactor as an example. The nuclear power plant 1 shown in this figure includes a nuclear reactor 10 including a primary cooling system, a secondary cooling system 20, and a water supply / main steam system 30. Further, the nuclear power plant 1 is provided with a reactor cooling device 40 that passively cools the reactor 10. These are configured as follows.

<Reactor 10>
The nuclear reactor 10 includes a core 11, an inner reactor vessel 12 that houses the core 11, and an outer reactor vessel 13 that covers the inner reactor vessel 12. Further, an intermediate heat exchanger 14 and a primary circulation pump 15 are housed inside the inner furnace container 12.

Of these, the core 11 is an aggregate of nuclear fuel and contains fissile material.

The inner reactor vessel 12 is a reactor vessel in which the primary coolant L1 is housed, and the core 11 is further housed in a state of being immersed in the primary coolant L1. As a result, the primary coolant L1 that fills the inner furnace vessel 12 is heated by the core 11. As the primary coolant L1, a liquid metal coolant such as sodium is used.

The outer furnace vessel 13 is also referred to as a guard vessel, and is arranged so as to cover the periphery of the inner furnace vessel 12 with a gap provided between the outer furnace vessel 13 and the inner furnace vessel 12. The space between the inner furnace vessel 12 and the outer furnace vessel 13 has a volume in which the core 11 is not exposed from the primary coolant L1 when the primary coolant L1 in the inner furnace vessel 12 leaks to the outer furnace vessel 13. doing. Further, when an inert gas G is filled in this space and the primary coolant L1 in the inner furnace container 12 leaks to the outer furnace container 13, oxidation of a liquid metal coolant such as sodium as the primary coolant L1 Is prevented.

The intermediate heat exchanger 14 is internally provided with a pipe structure 14a extending from the secondary cooling system 20 described below. The tube structure 14a is a portion where a liquid metal coolant such as sodium is filled as the secondary coolant L2 and the secondary coolant L2 circulates with the secondary cooling system 20. The secondary coolant L2 circulating in the pipe structure 14a is heated by the primary coolant L1 in the inner furnace vessel 12.

The primary circulation pump 15 is immersed in the primary coolant L1 in the inner furnace container 12 to circulate the primary coolant L1 in the inner furnace container 12. As a result, in the tank type fast breeder reactor, the inner furnace container 12 accommodating the intermediate heat exchanger 14 serves as a primary cooling system for circulating the primary coolant L1. For this reason, the tank-type fast breeder reactor does not require primary cooling system piping, and the entire plant can be made compact.

<Secondary cooling system 20>
The secondary cooling system 20 includes a secondary cooling pipe 21, a steam generator 22, and a secondary circulation pump 23.

Of these, the secondary cooling pipe 21 communicates between the steam generator 22 and the pipe structure 14a of the intermediate heat exchanger 14 at two locations, and is connected to the pipe structure 14a of the steam generator 22 and the intermediate heat exchanger 14. A circulation path for the secondary coolant L2 is formed between the two. The secondary cooling pipe 21 is filled with the secondary coolant L2.

The steam generator 22 has a configuration in which secondary cooling pipes 21 communicate with each other at both ends, and the inside is filled with the secondary coolant L2. A thin tube 22a is arranged inside the steam generator 22. The thin tube 22a is connected to the water supply / main steam system 30 described below, and has a configuration in which water is supplied to the inside. Such a steam generator 22 generates steam by heating the water supplied into the thin tube 22a with the secondary coolant L2.

The secondary circulation pump 23 is provided in the secondary cooling pipe 21, and circulates the secondary coolant L2 between the steam generator 22 and the pipe structure 14a of the intermediate heat exchanger 14 via the secondary cooling pipe 21. Let me.

<Water supply / main steam system 30>
The water supply / main steam system 30 includes a main steam pipe 31, a high pressure turbine 32, a low pressure turbine 33, a generator 34, a condenser 35, a feed water supply / recovery system pipe 36, a water supply pump 37, and a feed water heater 38.

Of these, the main steam pipe 31 is connected to the thin pipe 22a of the steam generator 22 and guides the steam generated by the steam generator 22 to the high-pressure turbine 32. The high-pressure turbine 32 and the low-pressure turbine 33 are arranged coaxially and are rotated by steam supplied from the steam generator 22 via the main steam pipe 31. The generator 34 is coaxially connected to the high-pressure turbine 32 and the low-pressure turbine 33, and operates by the rotation of the high-pressure turbine 32 and the low-pressure turbine 33 to generate electricity.

The condenser 35 is connected to the low pressure turbine 33, and steam is guided from the low pressure turbine 33. A cooling pipe 35a is arranged in the condenser 35, and the steam guided from the low-pressure turbine 33 is condensed and returned to water.

The water supply / recovery system pipe 36 is arranged between the condenser 35 and the steam generator 22, and communicates the condenser 35 and the thin pipe 22a of the steam generator 22.

The water supply pump 37 is provided in the water supply / recovery system pipe 36, and boosts the water condensed by the condenser 35 to the thin pipe 22a of the steam generator 22 via the water supply / recovery system pipe 36 to supply water. The feed water heater 38 heats the water to be supplied to the thin tube 22a of the steam generator 22.

<Reactor cooling device 40>
Next, the configuration of the reactor cooling device 40 for cooling the reactor 10 will be described. FIG. 2 is a configuration diagram (No. 1) of the reactor cooling device 40 according to the embodiment, in which a vertical cross section of the reactor 10 and its surroundings is connected to each pipe constituting the reactor cooling device 40. It is a figure which shows the state. Further, FIG. 3 is a configuration diagram (No. 2) of the reactor cooling device according to the embodiment, in which a horizontal cross section of the reactor 10 and its surroundings is connected to each pipe constituting the reactor cooling device 40. It is a figure which shows the state.

The reactor cooling device 40 shown in these figures has a natural circulation passage of a cooling medium for cooling the heat of the reactor 10, and in particular, the natural cooling medium for removing decay heat generated when the reactor is shut down. It has a circulation pathway. Such a reactor cooling device 40 has, for example, a reactor vessel auxiliary cooling system (Reactor Vessel Auxiliary. Cooling System: RVACS) that takes in outside air as a cooling medium and naturally circulates the outside air.

The reactor cooling device 40 includes a concrete structure 41 for accommodating the reactor 10, a tubular member 42 arranged in the concrete structure 41, a descending passage 43 and an ascending passage 44 separated by the tubular member 42. Be prepared. Further, the reactor cooling device 40 includes an introduction pipe 45 connected to the descending passage 43 and a discharge pipe 46 connected to the ascending passage 44, and the air (outside air) for cooling the heat of the reactor 10 by these is provided. A natural circulation passage is constructed. Further, the reactor cooling device 40 includes a preliminary introduction pipe 50 and a preliminary discharge pipe 60 in addition to the natural circulation passage. Hereinafter, each of these components will be described.

[Concrete structure 41]
The concrete structure 41 includes a storage portion 41a as a space for housing the reactor 10. The concrete structure 41 accommodates the reactor 10 in the accommodating portion 41a in a state where the side wall and the bottom surface portion of the accommodating portion 41a are spaced apart from the reactor 10. Such a concrete structure 41 is provided by digging under the ground surface.

[Cylindrical member 42]
The tubular member 42 is arranged in the accommodating portion 41a of the concrete structure 41 so as to surround the side circumference of the reactor 10 and is installed with a gap between it and the bottom surface portion of the accommodating portion 41a. Such a tubular member 42 functions as a heat collector to which radiant heat from the reactor 10 is transferred.

[Descent passage 43]
The descending passage 43 is a space portion between the side wall of the accommodating portion 41a and the tubular member 42 in the concrete structure 41, and is an outer space portion surrounding the tubular member 42. The descending passage 43 serves as a distribution path for the gas taken in from the introduction pipe 45, which will be described later, to flow downward.

[Ascending passage 44]
The ascending passage 44 is a space portion between the tubular member 42 and the reactor 10, and is a space portion surrounding the reactor 10. The ascending passage 44 is a portion where the gas inside the ascending passage 44 is warmed and ascended by the radiant heat from the reactor 10. Such movement of gas in the ascending passage 44 causes an inflow of gas from the descending passage 43 communicating with the ascending passage 44 at the lower end and a descending of gas in the descending passage 43.

[Introduction pipe 45]
The introduction pipe 45 is a pipe for introducing outside air provided in communication with the descending passage 43, and here, an example shows a configuration in which two introduction pipes 45 communicate with the descending passage 43. Each introduction pipe 45 is connected to the descending passage 43 at the upper end or the vicinity of the upper end of the descending passage 43. It is assumed that the connection position of each introduction pipe 45 with the descending passage 43 is buried under the ground surface. Further, in each introduction pipe 45, the end portion opposite to the connection position with the descending passage 43 is an opening end serving as an introduction port 45a for outside air, and is arranged on the ground.

The introduction port 45a is provided with a closing member 45b for closing the introduction pipe 45. The closing member 45b is, for example, an electric lid, and when the power is not turned on at all times, the introduction port 45a of the introduction pipe 45 is opened to open the introduction pipe 45. On the other hand, the closing member 45b closes the introduction port 45a of the introduction pipe 45 when the power is turned on. As a result, as shown in the following operation description, the loss of the cooling effect due to the inflow and outflow of gas into and out of the introduction pipe 45 is prevented when the power is turned on. Such a closing member 45b is powered on in conjunction with the turbomachine described below, and closes the introduction pipe 45 in conjunction with the drive of the turbo machine.

The number of introduction pipes 45 connected to the descending passage 43 is not limited to two, as long as the amount of air circulation required to remove the decay heat generated when the reactor is shut down can be secured. It may be one or a plurality of three or more.

[Discharge pipe 46]
The discharge pipe 46 is a pipe for gas discharge provided in communication with the ascending passage 44, and here exemplifies a configuration in which two discharge pipes 46 communicate with the ascending passage 44. Each discharge pipe 46 is connected to the ascending passage 44 at the upper end or the vicinity of the upper end of the ascending passage 44. It is assumed that the connection position of each discharge pipe 46 with the ascending passage 44 is buried under the ground surface. Further, each discharge pipe 46 is a stack extending upward and has an inner diameter and a height that effectively raises the gas warmed in the ascending passage 44, whereby air in the natural circulation path is provided. Achieve the natural circulation of. In each discharge pipe 46, the end opposite to the connection position with the ascending passage 44 is an open end serving as an outside air discharge port 46a, and is arranged on the ground.

The discharge port 46a is provided with a closing member 46b for closing the discharge pipe 46. The closing member 46b is, for example, an electric lid, and when the power is not turned on at all times, the discharge port 46a of the discharge pipe 46 is opened to open the discharge pipe 46. On the other hand, the closing member 46b closes the discharge port 46a of the discharge pipe 46 when the power is turned on. As a result, when the power is turned on, the loss of the cooling effect due to the inflow and outflow of the gas into the discharge pipe 46 is prevented. Such a closing member 46b is powered on in conjunction with the turbomachine described below, and closes the discharge pipe 46 in conjunction with the drive of the turbomachine.

The number of discharge pipes 46 connected to the ascending passage 44 is not limited to two, as long as the amount of air circulation required to remove the decay heat generated when the reactor is shut down can be secured. It may be one or a plurality of three or more.

[Preliminary introduction pipe 50]
The spare introduction pipe 50 is a spare pipe provided so as to communicate with the descending passage 43. The preliminary introduction pipe 50 is for introducing air into the descending passage 43 in place of the introduction pipe 45, which has a particularly strong suction force in the natural circulation passage and is easily blocked by the intrusion of foreign matter from the outside. Such a preliminary introduction pipe 50 is configured to be directly connected to the descending passage 43. Since the descending passage 43 is provided so as to cover the periphery of the reactor 10, it has a wide opening width and is difficult to close, and is suitable as a connecting portion of the preliminary introduction pipe 50. As shown in the figure, the connection portion of the preliminary introduction pipe 50 to the descending passage 43 is, for example, the side wall of the accommodating portion 41a in the concrete structure 41, preferably above the inner furnace vessel 12.

The end of the pre-introduction pipe 50 opposite to the connection position with the descending passage 43 is a pre-introduction port 50a into which gas is introduced. Such a preliminary introduction pipe 50 is provided with a first on-off valve 51, a turbomachine 52, a second on-off valve 53, and a check valve 54 in this order from the preliminary introduction port 50a side.

Of these, the first on-off valve 51 is provided close to the preliminary introduction port 50a in the preliminary introduction pipe 50, normally closes the preliminary introduction pipe 50, and interlocks with the turbo machine 52 described below to provide the preliminary introduction pipe. Open 50. As such a first on-off valve 51, for example, an electric valve is used. The first on-off valve 51 closes the preliminary introduction pipe 50 at all times when the power is not turned on, thereby preventing foreign matter from entering the preliminary introduction pipe 50. Further, by using the first on-off valve 51 as an electric valve, the spare introduction pipe 50 can be opened at the timing of driving the turbo machine 52, so that the turbo machine 52 pumps air from the spare introduction pipe 50. Can be carried out efficiently. The power of the first on-off valve 51 is turned on in conjunction with the turbomachine 52 and the closing member 45b provided on the introduction pipe 45 and the closing member 46b provided on the discharge pipe 46.

The turbomachine 52 is driven in conjunction with the first on-off valve 51, and in a state where the first on-off valve 51 opens the preliminary introduction pipe 50, gas is pumped to the introduction pipe 45 side. It is important that such a turbomachine 52 has a pumping capacity sufficient to secure the amount of air circulation required for removing the decay heat of the core 11 generated when the reactor is shut down. In such a turbo machine 52, for example, the impeller is a centrifugal type in consideration of the amount of heat of decay heat generated by the core 11, the physical properties of air used as a cooling medium, the flow velocity in the flow path, and the pressure loss in the flow path. A compressor is used. The power of such a turbomachine 52 is turned on in conjunction with the first on-off valve 51 and the closing member 45b provided on the introduction pipe 45 and the closing member 46b provided on the discharge pipe 46.

The second on-off valve 53 is provided in the preliminary introduction pipe 50 close to the connection position with the introduction pipe 45, constantly closes the preliminary introduction pipe 50, and interlocks with the drive of the turbomachine 52 to move the preliminary introduction pipe 50. Open it. As such a second on-off valve, for example, an electric valve is used. The second on-off valve 53 closes the pre-introduction pipe 50 at all times when the power is not turned on, thereby preventing the inflow of gas from the descending passage 43 into the pre-introduction pipe 50 and reducing the loss of the cooling effect due to natural circulation. To prevent. By using the second on-off valve 53 as an electric valve, the spare introduction pipe 50 can be opened at the timing of driving the turbomachine 52. Therefore, the turbomachine 52 pumps air from the spare introduction pipe 50. It can be carried out efficiently. The second on-off valve 53 may be an air-operated valve. In this case, the second on-off valve 53 is provided so as to open the preliminary introduction pipe 50 in a state where the pressure on the preliminary introduction port 50a side is higher than a predetermined value with respect to the pressure on the descending passage 43 side.

The check valve 54 is provided in the preliminary introduction pipe 50 near or at the connection position with the descending passage 43 to prevent gas from flowing into the preliminary introduction pipe 50 from the descending passage 43. This prevents loss of cooling effect due to natural circulation.

It is preferable that the preliminary introduction pipe 50 provided with the above-mentioned members is designed to have a smaller total opening area than the introduction pipe 45. Further, the preliminary introduction pipe 50 needs to slow down the flow velocity in the pipe on the upstream side of the turbomachine 52 on the downstream side. Therefore, it is assumed that the preliminary introduction pipe 50 is designed so that the inner diameter on the upstream side of the turbomachine 52 is larger than that on the downstream side.

Further, the length of the preliminary introduction pipe 50 is preferably designed so that the distance between the turbomachine 52 and the reactor 10 can be considerably separated, for example, as a countermeasure against terrorism. For example, assuming that the distance between the turbomachine 52 and the reactor 10 is about 100 m in a straight line, the length of the preliminary introduction pipe 50 is about 150 m in consideration of the layout.

The number of the spare introduction pipes 50 as described above is not limited to one, and is necessary for removing the decay heat generated when the reactor is shut down, especially when the introduction pipe 45 is blocked. As long as the amount of air circulation can be secured, a plurality of air may be used. However, since the spare introduction pipe 50 includes a power machine such as a turbo machine 52, it is preferable that the number of spare introduction pipes 50 is small. Further, the preliminary introduction pipe 50 may be branched from the introduction pipe 45.

[Preliminary discharge pipe 60]
The spare discharge pipe 60 is a spare pipe for gas discharge provided in communication with the ascending passage 44, and is configured to be directly connected to the ascending passage 44 here. Since the ascending passage 44 is provided so as to cover the periphery of the descending passage 43, the opening width is wide and it is difficult to block the ascending passage 44, and the ascending passage 44 is suitable as a connecting portion of the preliminary discharge pipe 60. As shown in the drawing, the connection portion of the preliminary discharge pipe 60 to the ascending passage 44 is, for example, a portion through which the tubular member 42 is penetrated, and is preferably above the inner furnace vessel 12. The end of the spare discharge pipe 60 opposite to the connection position with the discharge pipe 46 is a spare discharge port 60a from which gas is discharged.

The spare discharge pipe 60 as described above is provided with a first air-operated valve 61 and a second air-operated valve 62 in this order from the connection side with the rising passage 44. The first air-operated valve 61 and the second air-operated valve 62 are arranged at both ends of the preliminary discharge pipe 60, and the pressure on the connection portion side with the rising passage 44 is higher than the pressure on the preliminary discharge port 60a side. It is an on-off valve that opens the spare discharge pipe 60 in a state where it is higher than a predetermined value. These on-off valves open the spare discharge pipe 60 in the order of the first air-operated valve 61 and the second air-operated valve 62.

As described above, by providing the first air operating valve 61 on the connection side of the preliminary discharge pipe 60 with the rising passage 44, the rising passage is in a state where the discharge pipe 46 is always open when the power is not turned on. The inflow of gas from 44 to the preliminary discharge pipe 60 is prevented. As a result, the effect of raising the gas in the discharge pipe 46 is not hindered, and the cooling effect due to natural convection is maintained. Further, by providing the second air-operated valve 62 at the preliminary discharge port 60a in the preliminary discharge pipe 60, it is possible to prevent foreign matter from entering the preliminary discharge pipe 60.

The preliminary discharge pipe 60 provided with each of the above members is designed to have a smaller total opening area than the discharge pipe 46, for example, having a circular cross section and a diameter of about 1 m. The number of spare discharge pipes 60 provided with the first air-operated valve 61 and the second air-operated valve 62 as described above is not limited to one, and when the discharge pipe 46 is blocked. As long as the amount of air circulation required to remove the decay heat generated when the reactor is shut down can be secured, the number may be multiple. Further, the spare discharge pipe 60 may be branched from the discharge pipe 46.

<Operation of reactor cooling device 40>
As the operation of the reactor cooling device 40 configured as described above, the operation at all times will be described first, and then the operation in the state where the power is turned on to the reactor cooling device 40 will be described.

First, at all times, the reactor cooling device 40 is in a state where the power is not turned on. Therefore, the closing member 45b provided on the introduction pipe 45 and the closing member 46b provided on the discharge pipe 46 are in an open state, and the introduction pipe 45 and the discharge pipe 46 are in an open state. On the other hand, the first on-off valve 51 and the second on-off valve 53 provided in the preliminary introduction pipe 50 are in a state in which the preliminary introduction pipe 50 is closed.

In the above state, for example, when decay heat is generated from the reactor 10 when the reactor is shut down, the gas in the ascending passage 44 is warmed by the radiant heat. Then, the warmed gas rises in the ascending passage 44, and the warmed gas is discharged from the discharge port 46a of the discharge pipe 46 connected to the ascending passage 44. Further, when the pressure inside the ascending passage 44 becomes negative due to the rise of gas, gas is supplied to the ascending passage 44 from the descending passage 43 communicating with the ascending passage 44 at the lower end. Further, outside air taken in from the introduction port 45a of the introduction pipe 45 is supplied to the descending passage 43.

As described above, in the reactor cooling device 40, the decay heat generated in the reactor 10 is passively cooled by the natural circulation of the outside air taken in from the introduction port 45a of the introduction pipe 45.

Since the gas that has risen up the rising passage 44 and is supplied to the discharge pipe 46 is discharged from the discharge port 46a, the pressure in the discharge pipe 46 is maintained in a predetermined state. Therefore, the first air-operated valve 61 and the second air-operated valve 62 provided in the spare discharge pipe 60 connected to the discharge pipe 46 do not open.

Next, the operation when the power is turned on to the reactor cooling device 40 will be described. FIG. 4 is a configuration diagram (No. 3) of the reactor cooling device 40 according to the embodiment, and is a diagram for explaining the operation when the power is turned on to the reactor cooling device 40. As shown in this figure, when the power is turned on to the reactor cooling device 40, the closing member 45b closes the introduction port 45a, and the closing member 46b closes the discharge port 46a. On the other hand, the first on-off valve 51 and the second on-off valve 53 provided in the preliminary introduction pipe 50 open the preliminary introduction pipe 50. Further, the turbomachine 52 provided in the preliminary introduction pipe 50 operates to pump the air (for example, outside air) taken in from the preliminary introduction port 50a of the preliminary introduction pipe 50 toward the descending passage 43 side.

In such a state, when the gas in the ascending passage 44 is warmed by the radiant heat from the reactor 10, the warmed gas rises in the ascending passage 44 and is supplied to the discharge pipe 46 connected to the ascending passage 44. Will be done. However, since the discharge pipe 46 is closed by the closing member 46b, the pressure in the discharge pipe 46 and the ascending passage 44 increases. As a result, the first air-operated valve 61 of the spare discharge pipe 60 connected to the ascending passage 44 opens, and then the second air-operated valve 62 opens, whereby the spare discharge pipe 60 opens. Then, the air in the ascending passage 44 is discharged from the preliminary discharge port 60a of the preliminary discharge pipe 60.

Further, by pressure feeding from the turbomachine 52 provided in the preliminary introduction pipe 50, the gas taken in from the preliminary introduction port 50a of the preliminary introduction pipe 50 is sent to the descending passage 43 and communicates with the descending passage 43 at the lower end of the descending passage 43. Gas is sent to the rising passage 44. As a result, the decay heat generated in the reactor 10 is introduced from the pre-introduction port 50a of the pre-introduction pipe 50 and cooled by the gas (for example, air or outside air) pumped by the turbomachine 52.

<Effect of embodiment>
According to the embodiment described above, gas is supplied to the descending passage 43 by connecting the preliminary introduction pipe 50 having the turbo machine 52 to the descending passage 43 constituting the natural circulation path of air as a cooling medium. It is possible to pump. As a result, even if the natural circulation path is blocked for some reason, it is possible to continue supplying gas to the natural circulation path to the descending passage 43 and remove the decay heat of the core 11. It is possible to continue to maintain the cooling capacity required for this.

<< Modified example of the embodiment >>
FIG. 5 is a configuration diagram of a reactor cooling device according to a modified example of the embodiment, and is a diagram showing a vertical cross section of the reactor 10 and its surroundings and a connection state of each pipe, and is a reactor cooling. It is a figure for demonstrating the operation when the power is turned on to the apparatus 40'. The reactor cooling device 40'of the modified example shown in this figure has a configuration in which a moisture separator 55 is provided for the reactor cooling device 40 of the embodiment described with reference to FIGS. 2 to 4. The moisture separator 55 is arranged between the first on-off valve 51 and the turbomachinery 52 in the preliminary introduction pipe 50.

With such a configuration, if a liquid metal coolant such as sodium as the primary coolant L1 leaks out of the reactor 10 for some reason, the gas from which water has been removed by the moisture separator 55 Can be supplied to the descending passage 43 to cool the heat of the reactor 10. Further, in this case, the introduction pipe 45 is closed by the closing member 46b in conjunction with the driving of the turbo machine 52. Therefore, the introduction of outside air containing moisture is blocked. Therefore, the heat of the reactor 10 can be cooled without contacting the water with a liquid metal coolant such as sodium, which is the primary coolant L1.

The present invention is not limited to the above-described embodiments and modifications, and further includes various modifications. For example, the above-described embodiment has been described in detail in order to explain the present invention in an easy-to-understand manner, and is not necessarily limited to the one including all the described configurations. Further, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and as an example, the reactor is not limited to the tank type fast breeder reactor, and other fast breeder reactors. It may be a boiling water reactor or a pressurized water reactor. It is also possible to add the configuration of another embodiment to the configuration of one embodiment. Further, it is possible to add / delete / replace a part of the configuration of each embodiment with another configuration.

1 ... Nuclear plant 10 ... Reactor 11 ... Core 12 ... Inner reactor vessel 13 ... Outer reactor vessel 40 ... Reactor cooling device 42 ... Down passage (natural circulation passage)
44 ... Ascending passage (natural circulation passage)
45 ... Introduction pipe (natural circulation passage)
45a ... Introduction port (opening between introductions)
45b ... Closing member 46 ... Discharge pipe (natural circulation passage)
46a ... Discharge port (opening of discharge pipe)
46b ... Closing member 50 ... Spare introduction pipe (spare pipe)
50a ... Preliminary introduction port (open end of preliminary introduction pipe)
51 ... 1st on-off valve 52 ... Turbomachinery 53 ... 2nd on-off valve 54 ... Check valve 55 ... Moisture separator 60 ... Spare discharge pipe 61 ... 1st air-operated valve (on-off valve)
62 ... Second air actuated valve (open / close valve)
L1 ... Primary coolant (liquid metal coolant)
G ... Inert gas

Claims (15)

A natural circulation passage of the cooling medium for cooling the heat of the reactor,
With the spare piping connected to the natural circulation passage,
A nuclear reactor cooling device provided with a turbomachine provided in the spare pipe. The natural circulation passage
An ascending passage of the cooling medium connected to the outlet of the cooling medium and arranged so as to cover the periphery of the reactor.
It is provided with a lowering passage of the cooling medium which is connected to the introduction port of the cooling medium and is arranged so as to cover the outside of the rising passage and communicates with the rising passage at the lower end of the rising passage.
The spare pipe is connected to the descending passage as a spare introduction pipe.
The reactor cooling device according to claim 1, wherein the turbomachinery pumps a cooling medium from the preliminary introduction pipe toward the descending passage. The reactor cooling according to claim 2, wherein an on-off valve for closing the pre-introduction pipe and opening the pre-introduction pipe in conjunction with the drive of the turbomachinery is provided at the opening end of the pre-introduction pipe. apparatus. The reactor cooling device according to claim 3, wherein the on-off valve is an electric valve. Claim 2 is provided with an on-off valve that closes the preliminary introduction pipe and opens the preliminary introduction pipe in conjunction with the drive of the turbomachine on the connection portion side of the preliminary introduction pipe with the descending passage. Reactor cooling device according to. The check valve according to claim 2, wherein a check valve for preventing the inflow of the cooling medium from the descending passage side to the preliminary introduction pipe side is provided at the connection portion of the preliminary introduction pipe with the descending passage. Reactor cooling system. The natural circulation passage includes a discharge pipe connected to the upper part of the ascending passage and an introduction pipe connected to the upper part of the descending passage.
The reactor cooling device according to claim 2, wherein the openings of the introduction pipe and the discharge pipe are provided with a closing member that closes the openings in conjunction with the drive of the turbomachine. The reactor cooling device according to claim 2, wherein a preliminary discharge pipe is connected to the ascending passage. The preliminary discharge pipe is closed on the connection portion side of the preliminary discharge pipe with the ascending passage, and the pressure on the ascending passage side becomes higher than a predetermined value than the pressure on the preliminary discharge pipe side. The reactor cooling device according to claim 8, wherein an on-off valve for opening a pipe is provided. An on-off valve that closes the preliminary discharge pipe on the opening end side of the preliminary discharge pipe and opens the preliminary discharge pipe when the pressure on the ascending passage side becomes higher than a predetermined value than the pressure on the opening end side. The reactor cooling device according to claim 8, wherein the reactor cooling device is provided. The reactor cooling device according to claim 1, wherein the turbo machine is a compressor. The reactor cooling device according to claim 1, wherein the cooling medium is air. The reactor cooling device according to claim 2, wherein a moisture separator is provided on the opening end side of the pre-introduction pipe with respect to the turbomachine. Reactor and
A natural circulation passage for air that removes the heat of the reactor,
With the spare piping connected to the natural circulation passage,
A nuclear power plant equipped with a turbomachinery provided in the spare pipe. The reactor
An inner furnace vessel containing the core and liquid metal coolant,
The outer furnace vessel that houses the inner furnace vessel and
The nuclear power plant according to claim 14, further comprising an inert gas filled between the inner furnace vessel and the outer furnace vessel.

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