Reactor Systems

Abstract

To reduce the inefficiency of needing to install a nuclear power plant with a maximum manufacturing capacity.SOLUTION: A nuclear reactor system includes: a plurality of nuclear reactors using a coated fuel particle, a moderator, and a coolant; a steam generator; and a steam turbine connected to the steam generator. The plurality of nuclear reactors are connected to the single steam generator.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to nuclear reactor systems. [Background technology]

[0002] Conventionally, various nuclear power plants have been developed. For example, Patent Document 1 describes a nuclear power plant having multiple reactors installed on a site, the nuclear power plant including multiple reactor vessels each housing a multiple reactor core, multiple reactor containment vessels each housing the multiple reactor vessels, and a reactor building housing all of the multiple reactor containment vessels, the horizontal cross-sectional shape of the reactor building being approximately circular or approximately square. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 10-115692 Summary of the Invention [Means for solving the problem]

[0004] A reactor system according to a first aspect of the present invention comprises a plurality of reactors that use coated fuel particles, a moderator and a coolant, a steam generator that generates steam from thermal energy extracted from the reactors, and a steam turbine that is connected to the steam generator and converts the energy of the steam into rotational energy, and the plurality of reactors are connected to one of the steam generators.

[0005] A nuclear reactor system according to a second aspect of the present invention is the nuclear reactor system according to the first aspect, in which piping extends horizontally radially from the steam generator, and the nuclear reactor is connected to the end of the piping.

[0006] A reactor system according to a third aspect of the present invention is a reactor system according to the first aspect, wherein a pipe extending from the steam generator branches off along the way, and the reactor is connected to each of the branches.

[0007] A reactor system according to a fourth aspect of the present invention is a reactor system according to any one of the first to third aspects, wherein each of the multiple reactors and the steam generator are connected by double piping, and the double piping is composed of an inner tube and an outer tube that covers the inner tube at intervals in the circumferential direction, and high-temperature gas passing from the reactor to the steam generator passes through the inner tube, and low-temperature gas returning from the steam generator to the reactor passes through the outer tube.

[0008] A nuclear reactor system according to a fifth aspect of the present invention is a nuclear reactor system according to any one of the first to fourth aspects, wherein the reactor and / or the steam generator are supported from below by a structure that allows horizontal thermal expansion.

[0009] A nuclear reactor system according to a sixth aspect of the present invention is the nuclear reactor system according to the fifth aspect, in which the structure that allows horizontal thermal expansion is a free ball bearing.

[0010] A reactor system according to a seventh aspect of the present invention is a reactor system according to any one of the first to sixth aspects, wherein the reactor and / or the steam generator are supported by a support structure that suppresses shaking due to vibration during an earthquake.

[0011] A nuclear reactor system according to an eighth aspect of the present invention is the nuclear reactor system according to the seventh aspect, wherein the support structure is a damper.

[0012] A reactor system according to a ninth aspect of the present invention is a reactor system according to any one of the first to eighth aspects, wherein the reactor and the steam generator are arranged on a first level, and the steam turbine is arranged on a second level above the first level.

[0013] A reactor system according to a tenth aspect of the present invention is a reactor system according to any one of the first to ninth aspects, further comprising a coolant purification equipment that purifies the coolant and cools the coolant, an intake piping that connects the multiple reactors to the intake ports of the coolant purification equipment, and a discharge piping that connects the multiple reactors to the discharge ports of the coolant purification equipment, and if the reactors cannot be cooled normally, the coolant is cooled by passing it through the coolant purification equipment, and the cooled coolant is supplied to the reactors again.

[0014] A nuclear reactor system according to an eleventh aspect of the present invention is the nuclear reactor system according to any one of the first to tenth aspects, wherein the nuclear reactor is a gas-cooled reactor. Effect of the Invention

[0015] According to one aspect of the present invention, by installing multiple low-output nuclear reactors in the required number according to the power demand and connecting the thermal energy extracted from the multiple reactors to a single steam generator, it is possible to generate electricity according to the power demand, thereby improving efficiency. [Brief description of the drawings]

[0016] [Figure 1] 1 is a schematic diagram showing an example of a nuclear reactor system according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a schematic diagram showing an example of a connection mode between a steam generator and a reactor in a reactor system according to another first aspect of the present embodiment. [Figure 3A] FIG. 11 is a schematic diagram showing an example of a connection mode between a steam generator and a reactor in a reactor system according to another second aspect of the present embodiment. [Figure 3B] FIG. 11 is a perspective view showing an example of the configuration of a reactor system according to another second aspect of the present embodiment. [Figure 3C] FIG. 2 is a perspective view showing an example of a double pipe configuration of the present embodiment. [Figure 4] FIG. 2 is a schematic diagram showing an example of a support mode of a reactor in the reactor system of the present embodiment. [Diagram 5] FIG. 2 is a schematic diagram showing an example of a method for fixing a nuclear reactor. [Figure 6] FIG. 2 is a schematic diagram showing an example of the installation of components of a nuclear reactor system. [Figure 7] FIG. 2 is a schematic diagram illustrating an example of a cooling mechanism. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, each embodiment will be described with reference to the drawings. However, more detailed description than necessary may be omitted. For example, detailed description of already well-known matters or duplicate description of substantially the same configuration may be omitted. This is to avoid the following description becoming unnecessarily redundant and to facilitate understanding by those skilled in the art.

[0018] Because nuclear reactors are costly to develop, the most recently developed reactors are usually installed when building new nuclear power plants. This means that reactors with output that matches electricity demand are not selected, and there is an issue of inefficiency in that nuclear power plants with the maximum production capacity must be built even in areas where electricity demand is not that great.

[0019] In this embodiment, to address this issue, only the necessary number of small-output nuclear reactors are installed to meet the demands of the power demand areas, and the number of steam generators that generate steam from the thermal energy extracted from the nuclear reactors, steam turbines that convert the steam into power, and generators that convert the power into electricity are limited to one or a minimum number, thereby improving efficiency and solving the issue.In addition, since multiple nuclear reactors are connected to one steam generator and steam turbine using branch piping (e.g., T-shaped piping), the amount of equipment incorporated into the nuclear reactor system can be rationally reduced as much as possible, and manufacturing and construction costs can be reduced.

[0020] In addition to the above-mentioned problems, a second problem is that in the reactor system according to this embodiment, multiple reactor pressure vessels which become hot are installed, which causes large stresses (e.g., thermal stress or loads due to earthquakes, etc.) in the nozzles to which the piping connecting the reactor pressure vessels and the steam generators is attached, which may result in damage to the equipment. To address this second issue, in order to absorb the thermal displacement of the reactor pressure vessel, which becomes very hot, the reactor and / or steam generator are fitted with a structure (e.g., free ball bearings) that allows them to move horizontally in response to thermal expansion, supporting the vertical load while not restricting horizontal displacement.

[0021] In addition to the above issues, adding new equipment to improve safety poses another issue in that it worsens economic efficiency and introduces operational complexity, which brings with it concerns about new accidents, etc. To address this issue, in order to improve the safety of nuclear reactors without using additional equipment, heat dissipation via equipment that purifies the coolant helium during normal operation can be used as a cooling system in the event of an accident, thereby solving the issues of reduced economic efficiency and complicated operations.

[0022] Fig. 1 is a schematic diagram showing an example of a reactor system according to the present embodiment. As shown in Fig. 1, the reactor system S includes a reactor 1, a reactor 2, a steam generator 3 to which the reactor 1 and the reactor 2 are connected via a first pipe P1 and a second pipe P2, a steam turbine 4 in communication with the steam generator 3, a generator 5 connected to the steam turbine 4, a condenser 6 in communication with the steam turbine 4, and a circulator (Gas Circulator: GC) 7 for circulating a coolant (e.g., low-temperature helium). The steam generator 3 generates steam from thermal energy extracted from the reactor. The steam turbine 4 converts the energy of the steam into rotational energy. The generator 5 converts the rotational energy into electricity.

[0023] According to one embodiment, high-temperature helium produced in the reactors 1, 2 using heat released by nuclear fission of uranium is sent to the steam generator 3 via the first pipe P1. The steam generator 3 uses the high-temperature helium to turn water into steam, and the power of the steam turns the steam turbine 4, which generates electricity in the connected generator 5. After turning the steam turbine 4, the steam is cooled in the condenser 6 and turned back into water, and then sent to the steam generator 3. When the high-temperature helium turns water into steam in the steam generator 3, the temperature is reduced and it becomes low-temperature helium, and this low-temperature helium is sent to the reactors 1, 2 via the second pipe P2 by the circulator 7.

[0024] Reactor 1 and Reactor 2 use coated fuel particles, a moderator (e.g., graphite), and a coolant (e.g., helium gas). The moderator slows down the high-speed neutrons generated by nuclear fission in the reactor, making it easier for the next nuclear fission to occur. For example, graphite, which does not absorb neutrons easily, is used as a moderator. On the other hand, the coolant is used to extract the heat generated in the reactor.

[0025] In one example, reactor 1 and reactor 2 are gas-cooled reactors, i.e., high-temperature gas-cooled reactors, which use, for example, graphite as a moderator and helium as a coolant. Due to the high core temperature, the coated fuel particles are coated, for example, with a ceramic material.

[0026] Note that the reactors 1 and 2 are not limited to the gas-cooled reactors described above, but may be water-cooled reactors, liquid metal-cooled reactors, or molten salt reactors. Water-cooled reactors include light water-cooled reactors and heavy water-cooled reactors. In the case of light water-cooled reactors, light water (ordinary water) may be used both as a moderator and a coolant.

[0027] Fig. 2 is a schematic diagram showing an example of a connection mode between a steam generator and a reactor in a reactor system according to another first aspect of this embodiment. As shown in Fig. 2, pipes may extend radially in the horizontal direction from the steam generator 3 (specifically, for example, a plurality of nozzles of the steam generator 3), and the reactors 11, 12, 13, and 14 may be connected to the ends of the pipes. This makes it possible to adjust the output. Note that each of the reactors 11, 12, 13, and 14 may be connected to the steam generator 3 by a double pipe, which will be described later.

[0028] FIG. 3A is a schematic diagram showing an example of a connection mode between a steam generator and a reactor in a reactor system according to another second aspect of this embodiment. FIG. 3B is a perspective view showing an example of a configuration of a reactor system according to another second aspect of this embodiment. FIG. 3C is a perspective view showing an example of a configuration of a double pipe according to this embodiment. As shown in FIG. 3A and FIG. 3B, a double pipe P10 extending from a steam generator 3 (specifically, for example, a nozzle of the steam generator 3) branches on the way, and each of the branched ends is connected to one reactor (for example, the lower surface side of the reactor as shown in FIG. 3B), so that two reactors 21, 22 are connected to one steam generator 3. As shown in FIG. 3A and FIG. 3C, the double pipe P10 is composed of an inner pipe P11 and an outer pipe P12 that covers the inner pipe P11 at an interval in the circumferential direction. As shown in FIG. 3C, high-temperature gas from the reactors 21, 22 toward the steam generator 3 passes through the inner pipe P11. On the other hand, the outer tube 12 passes low-temperature gas returning from the steam generator 3 to the reactors 21 and 22 . Similarly, as shown in Figures 3A and 3B, a double pipe P20 extending from the steam generator 3 (specifically, for example, a nozzle of the steam generator 3) branches off midway, and each of the branches is connected to one reactor (for example, the underside of the reactor as shown in Figure 3B), thereby connecting two reactors 23, 24 to one steam generator 3. The double pipe P20 is composed of an inner pipe P21 and an outer pipe P22 that covers the inner pipe P21 at intervals in the circumferential direction. High-temperature gas traveling from the reactors 23, 24 to the steam generator 3 passes through the inner pipe P21. On the other hand, low-temperature gas returning from the steam generator 3 to the reactors 23, 24 passes through the outer pipe 22. As shown in Fig. 3B, circulators (Gas Circulators: GC) 71, 72 that circulate a coolant (for example, low-temperature helium) are provided and connected to the steam generator 3. The circulators 71, 72 circulate the coolant between the reactors 21-24 and the steam generator 3. By installing multiple circulators, even if one is stopped for maintenance, the remaining circulators can be operated to keep the reactors running, improving economic efficiency.

[0029] By combining one or more of these configurations in which two nuclear reactors are connected to one steam generator by branch piping (for example, T-shaped piping), it is possible to efficiently increase power output.

[0030] The nozzles, which are the parts connecting the nozzle stubs and piping installed in the steam generator 3, are subject to large stress (e.g., thermal stress or loads from earthquakes, etc.), but the more nozzles there are, the greater the stress becomes. In response to this, as described above, by connecting two reactors to one steam generator by branch piping (e.g., T-shaped piping), the number of connected reactors can be increased while the number of nozzles can be reduced relatively, thereby suppressing the increase in stress.

[0031] Fig. 4 is a schematic diagram showing an example of a support mode of the reactor in the reactor system of this embodiment. As shown in Fig. 4, the reactor 1 is supported from below by, as an example, a free ball bearing 31, which is an example of a structure that allows thermal expansion in the horizontal direction. Similarly, the reactor 2 is supported from below by, as an example, a free ball bearing 32, which is an example of a structure that allows thermal expansion in the horizontal direction. This makes it possible to alleviate stress that occurs by allowing thermal expansion in the horizontal direction even when the reactors 1 and 2 thermally expand in the horizontal direction.

[0032] In the example of Fig. 4, the reactors 1 and 2 are supported from below by free ball bearings 31 and 32, but this is not limited to the above, and in addition or instead, the steam generator 3 may be supported from below by a free ball bearing. On the other hand, the free ball bearing is not limited to being installed on the lower side (building side) of the reactor, and instead or in addition, it may be installed on the upper side (equipment side) of the reactor. In this way, all or any of the reactor and the foresteam generator are supported by a structure (e.g., a free ball bearing) that allows thermal expansion in the horizontal direction.

[0033] Fig. 5 is a schematic diagram showing an example of a method for fixing a nuclear reactor. As shown in Fig. 5, as an example, the nuclear reactor 1 is fixed to a building or structure via dampers 41, 42, 43, and 44. Here, the dampers 41, 42, 43, and 44 are an example of a support structure that suppresses vibrations caused by excitation during an earthquake. As a result, the dampers 41, 42, 43, and 44 absorb vibrations caused by excitation during an earthquake, so that the vibrations of the nuclear reactor 1 can be suppressed.

[0034] Although an example has been described here in which the reactor is supported by a support structure (e.g., a damper) that suppresses vibration due to excitation during an earthquake, in addition to or instead of this, the steam generator may be supported by a support structure (e.g., a damper) that suppresses vibration due to excitation during an earthquake. In this way, the reactor and / or the steam generator may be supported by a support structure that suppresses vibration due to excitation during an earthquake.

[0035] The reactors 1 and 2 and the steam generator 3 may be arranged on a first floor (also referred to as a lower floor), and the steam turbine 4 may be arranged on a second floor (also referred to as an upper floor) above the first floor. As one of the installation modes, an installation example in which the upper floor is above ground and the lower floor is underground will be described with reference to FIG. 6. FIG. 6 is a schematic diagram showing an installation example of components of a reactor system. In FIG. 6, the x-axis represents the horizontal direction, the z-axis represents the height direction, and the ground level (GL) which is a line on the ground surface is shown. The reactors 1 and 2, the steam generator 3, the steam turbine 4, and the generator 5 are provided in a reactor building 9. The reactors 1 and 2 and the steam generator 3 are arranged underground, and the steam turbine 4 and the generator 5 are arranged above ground.

[0036] Here, in the event of an abnormality such as an earthquake, cracks may form openings (not shown) in components such as door 54 of reactor building 9. By arranging reactors 1, 2 and steam generator 3 underground, openings in door 54, etc. can be shielded with surrounding soil 55 by construction machinery such as bulldozer 51, making it easy to take measures to prevent radioactive materials from dispersing in the event of an accident or abnormality.

[0037] In an emergency, the spread of radioactive materials can be easily suppressed by discharging water from a nozzle 53 of a hose connected to a tank of a fire engine or the like 52 capable of discharging water. In the above example, the first floor (lower floor) is described as being underground, but this is not limited thereto, and the first floor (lower floor) or the second floor (upper floor) may be semi-underground.

[0038] Fig. 7 is a schematic diagram for explaining an example of a cooling mechanism. As shown in Fig. 7, the reactor system S may further include a coolant purification facility 8 that purifies a coolant (e.g., helium) and cools the coolant, a suction pipe 61 that connects the reactors 1 and 2 to the suction ports of the coolant purification facility 8, and a discharge pipe 62 that connects the reactors 1 and 2 to the discharge ports of the coolant purification facility 8. In this case, when the reactors 1 and 2 cannot be normally cooled, the coolant (e.g., helium) is cooled through the coolant purification facility 8, and the cooled coolant is supplied to the reactors 1 and 2 again.

[0039] As a result, the coolant is cooled in the coolant purification facility 8, and the coolant is cooled in the suction pipe 61 and the discharge pipe 62, so that the coolant can be cooled and a cooling function can also be provided in the event of an abnormality.

[0040] As described above, the reactor system S of this embodiment comprises multiple reactors that use coated fuel particles, a moderator and a coolant, a steam generator 3 that generates steam from thermal energy extracted from the reactors, and a steam turbine 4 that is connected to the steam generator and converts the energy of the steam into rotational energy, with multiple reactors connected to one steam generator 3.

[0041] With this configuration, the reactors can be made smaller and multiple reactors can be installed in the number required to meet electricity demand. Furthermore, the thermal energy extracted from the multiple reactors can be connected to a single steam generator, making it possible to generate electricity in response to electricity demand and improving efficiency.

[0042] As described above, the present invention is not limited to the above-described embodiment as it is, and in the implementation stage, the components can be modified and embodied without departing from the gist of the invention. In addition, various inventions can be formed by appropriately combining the multiple components disclosed in the above-described embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, components from different embodiments may be appropriately combined. [Explanation of symbols]

[0043] 1, 11, 2, 21, 23, 25, 27 reactor 3. Steam generator 31, 32 Free ball bearing 4. Steam turbine 41 Damper 5. Generator 51 Bulldozer 52 Drainage truck 53 Nozzle 6. Condenser 61 Suction pipe 62 Discharge piping 7 Circulator 8. Coolant purification facility S Reactor System

Claims

1. a plurality of nuclear reactors using coated fuel particles, a moderator and a coolant; a steam generator that generates steam from thermal energy extracted from the nuclear reactor; a steam turbine communicating with the steam generator and converting energy of the steam into rotational energy; Equipped with the plurality of reactors are connected to only one of the steam generators; Each of the plurality of nuclear reactors and the steam generator are connected by a double pipe, the number of reactors is an even number, and each pair of reactors included in the even number of reactors are connected to the steam generator via a single joint, the branch pipes being made of double pipes connected to the respective reactors and joining together into a single double pipe; The double piping is composed of an inner pipe and an outer pipe that covers the inner pipe at a circumferential distance, the inner pipe is used for high-temperature gas flowing from the reactor to the steam generator, and the outer pipe is used for low-temperature gas flowing from the steam generator back to the reactor. The reactor and / or the steam generator are supported from below by a structure that allows for horizontal thermal expansion. Nuclear reactor systems.

2. Pipes extend horizontally radially from the steam generator, and the reactor is connected to the end of the pipes. The nuclear reactor system of claim 1 .

3. The piping extending from the steam generator branches along the way, and each branch is connected to the nuclear reactor. The nuclear reactor system of claim 1 .

4. The structure that allows for horizontal thermal expansion is a free ball bearing. The nuclear reactor system of claim 1 .

5. The reactor and / or the steam generator are supported by a support structure that suppresses vibrations caused by earthquakes. The nuclear reactor system of claim 1 .

6. The support structure is a damper. The nuclear reactor system of claim 5.

7. The nuclear reactor and the steam generator are disposed on a first level, and the steam turbine is disposed on a second level above the first level. The nuclear reactor system of claim 1 .

8. A coolant purification facility for purifying the coolant and cooling the coolant; a suction pipe connecting the plurality of reactors and a suction port of the coolant purification facility; a discharge pipe connecting the plurality of reactors and a discharge port of the coolant purification facility; Further comprising: When the reactor cannot be cooled normally, the coolant is passed through the coolant purification facility to be cooled, and the cooled coolant is supplied to the reactor again. The nuclear reactor system of claim 1 .

9. The reactor is a gas-cooled reactor. A nuclear reactor system according to any one of claims 1 to 8.

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