JP3913146B2 - Nuclear steam supply cassette and packaged reactor using the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a nuclear steam supply cassette used in a nuclear reactor, and more particularly, to a packaged atomic power source that is used as a non-network power source that is not connected to a power system network having a plurality of power supply sources and supplies independent power. The present invention relates to a furnace and a nuclear steam supply cassette used therein.
[0002]
[Prior art]
In regions where remote power sources are necessary, such as remote islands and remote areas that cannot be connected to power grids with other power sources due to geographical circumstances, the small scale required for those regions There is a need for a power supply system that supplies compact power with compact equipment.
Conventionally, diesel power generation, gas turbine power generation, and the like have been used in such areas, but attention has been focused on nuclear power generation that uses nuclear fuel that is easy to transport and costs less fuel for power generation.
[0003]
[Problems to be solved by the invention]
However, conventional nuclear power plants generally perform large power generation efficiently using large-scale equipment. For example, a reactor vessel used in a conventional nuclear power plant generally has a diameter of about 4 m and a height exceeding 10 m. Moreover, the output of nuclear power is generally several hundred thousand kW or more.
As a nuclear reactor used in such a large-scale nuclear power plant, there are various types of structures. As described in Japanese Patent Laid-Open No. 6-43279, steam is generated in addition to the core and the control rod. An integrated reactor in which a reactor is built in a reactor vessel has been proposed. FIG. 5 is a diagram schematically showing an example of the configuration of a conventional integrated nuclear reactor.
[0004]
According to this figure, the steam generator 3 is provided in the downcomer part 2 in the reactor vessel 1. Above the reactor vessel 1, a control rod driving device 6 that drives a control rod 5 inserted into the core 4 is disposed. The primary coolant 8 that circulates in the reactor vessel 1 through the downcomer section 2, the core 4, and the riser 7 is warmed by heat from nuclear fission in the core 4, and the secondary coolant (not shown) in the steam generator 3 Heat exchange between and cooled. The secondary coolant that has been deprived of heat from the primary coolant 8 and turned into steam is guided to a turbine (not shown) and is generated by a generator driven by the turbine.
However, if the steam generator 3 is built in the reactor vessel 1, the reactor vessel itself becomes even larger.
[0005]
As another type of nuclear reactor structure used in a large-scale nuclear power plant, as shown in FIG. 6, a pressure tube nuclear reactor using a pressure tube 14 incorporating a fuel body 13 has been proposed. ing. According to this, a plurality of pressure pipes 14 and control rods 15 are arranged in a cylindrical moderator tank 12 containing the moderator 11. The control rod 15 is connected to an external control rod driving device 16. The pressure pipe 14 is provided with a main steam pipe 17 and a main water supply pipe 18 and is connected to an external steam generator (not shown).
As described above, the fuel body 13 is built in the pressure pipe 14, but the steam generator is provided outside the pressure pipe 14. For this reason, it is necessary to provide a facility for an emergency breakage of the primary coolant main steam pipe 17 and the primary coolant main water supply pipe 18 through which the primary coolant circulating through the pressure pipe 14 and the external steam generator flows. Therefore, the nuclear power plant itself cannot be made compact.
[0006]
As described above, the structure of a conventional nuclear power plant has a large overall facility, and a conventional type nuclear power plant cannot be used as an energy supply source capable of generating small-scale electric power with a compact facility. There is a problem.
[0007]
The present invention has been made to solve such problems, and provides a nuclear steam supply cassette that can be used in a nuclear power plant as a non-network power source that is not connected to a power system network, and a packaged nuclear reactor using the same. The purpose is to do.
[0008]
[Means for Solving the Problems]
A nuclear steam supply cassette according to the present invention includes a pressure pipe, a core in the cassette made of a fuel body and a steam generator inside the pressure pipe, and a control rod can be disposed outside the pressure pipe. .
The pressure tube can have a reinforcing fiber layer on the outer periphery.
The nuclear steam supply cassette may include a pressure reducing valve that communicates with the inside of the pressure pipe outside the pressure pipe.
[0009]
A packaged nuclear reactor according to the present invention is configured by arranging a plurality of the above-described nuclear steam supply cassettes at intervals.
A packaged nuclear reactor can be provided with moderators and control rods between these multiple nuclear steam supply cassettes.
The packaged nuclear reactor may include a water shielding tank that stores shielding water supplied in a nuclear steam supply cassette.
The packaged nuclear reactor may include an emergency cooling water supply valve that communicates with the inside of the pressure pipe and the inside of the water shielding tank outside the pressure pipe.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
A sectional view of a nuclear steam supply cassette according to an embodiment of the present invention is shown in FIG. Moreover, the top view of the nuclear reactor using this nuclear steam supply cassette is shown in FIG. 2, and a longitudinal cross-sectional view is shown in FIG.
The nuclear steam supply cassette 21 includes a pressure tube 22, a steam generator 23 disposed from the center of the inner wall to the upper side thereof, and a cassette core 24 that is a fuel body provided below the steam generator 23. Yes.
[0011]
The pressure tube 22 is an elongated cylindrical tube having a diameter of about 50 cm and a length of several meters, for example, a pressure tube liner 25 made of a metal material such as stainless steel, and carbon fiber on the outer circumferential surface thereof. And a reinforcing fiber layer 26 that is rolled up to reinforce the strength. Between the pressure tube 22 and the core 24 in the cassette, a downcomer portion 27 in which the primary coolant 28 enclosed in the pressure tube 22 flows downward is formed. Further, a riser 29 is formed above the core 24 in the cassette to raise the primary coolant 28 heated by the core 24 in the cassette, so that the primary coolant 28 is indicated by an arrow in the pressure tube 22. It is configured to circulate.
[0012]
Next, FIGS. 2 and 3 show the structure of a packaged reactor 20 configured by combining a plurality of nuclear steam supply cassettes 21 configured as described above.
As directly shown in FIG. 3, seven nuclear steam supply cassettes 21 are arranged radially from the center in a moderator tank 31 filled with moderator 30 such as light water, heavy water, or graphite.
Around the center of the nuclear steam supply cassette 21 at the center, six control rods 32 for adjusting neutrons generated in the cassette core 24 and controlling the output of the reactor are arranged on the circumference. The control rod 32 is composed of three plate-like members extending between adjacent nuclear steam supply cassettes 21 and extends in the vertical direction along the core 24 in the cassette as shown in FIG. Are connected to the control rod drive 33.
The control rod driving device 33 controls the output of the nuclear reactor by moving the control rod 32 up and down along the in-cassette core 24 of the nuclear steam supply cassette 21. A heat insulating material 34 is wound around the outer circumferential surface of the moderator tank 31, and a water shielding tank 35 is provided outside the heat insulating material 34. The water shielding tank 35 is filled with shielding water 36, and this shielding water 36 shields neutrons and gamma rays emitted from each cassette core 24 during normal operation of the reactor 20 from the outside.
[0013]
As shown in FIG. 2, before the reactor 20 is started, the liquid level of the primary coolant 28 stored in the pressure pipe 22 is H1, and the steam generator 23 is submerged. A gas phase portion 28 a is formed on the upper portion of the pressure tube 22.
In addition, a secondary coolant pipe 44 provided with an on-off valve 41 is arranged in the middle of the upper part 21b of the nuclear steam supply cassette 21 as a supply / discharge path for the secondary coolant 43 of the steam generator 23. And connected to the pump.
Further, a pipe 39 is disposed through the upper portion 21 b of the nuclear steam supply cassette 21 and is connected to the pressure reducing valve 40 in the storage container 42.
[0014]
On the other hand, a pipe 37 penetrates the bottom 21 a of the nuclear steam supply cassette 21, and further passes through the bottom surface of the moderator tank 31 to the emergency cooling water supply valve 38 provided in the water shielding tank 35. It is connected.
When the heat generation function of the nuclear steam supply cassette 21 is lost, such as when heat exchange cannot be performed in the steam generator 23, the shield water 36 in the water shield tank 35 is transferred from the emergency cooling water supply valve 38 to the nuclear steam supply cassette 21. The core 24 in the cassette is cooled, and the steam generated in the nuclear steam supply cassette 21 is decompressed by the pressure reducing valve 40 and discharged to the outside of the nuclear steam supply cassette 21.
In addition, an air flow path 45 for air-cooling the storage container 42 is formed on the outer periphery of the storage container 42.
[0015]
Next, the operation of the package reactor using the nuclear steam supply cassette according to the embodiment of the present invention will be described.
During normal operation of the packaged reactor 20, the primary coolant 28 in the nuclear steam supply cassette 21 is naturally circulated in a single phase, warmed by the reaction heat of the core 24 in the cassette, rises the riser 29, and generates steam. In the vessel 23, heat exchange is performed with the secondary coolant. The cooled primary coolant 28 descends the downcomer portion 27 and is heated again in the cassette core 24.
In the steam generator 23, the secondary coolant 43, which has been deprived of heat from the primary coolant 28 and heated to become steam, is led to the turbine via the secondary coolant pipe 44 and is driven by the turbine. To generate electricity.
[0016]
As described above, the secondary coolant 44 is supplied as steam from each nuclear steam supply cassette 21 to the turbine and used for power generation, and a desired power generation amount can be obtained according to the number of the nuclear steam supply cassettes 21. it can.
Here, the number of the nuclear steam supply cassettes 21 can be appropriately selected according to the required output in the nuclear reactor. Therefore, a packaged nuclear reactor having a desired output can be configured according to the number of nuclear steam supply cassettes 21 accommodated in the nuclear reactor.
Further, since the pressure pipe 22 is formed with the reinforcing fiber layer 26 made of carbon fiber around the pressure pipe liner 25 made of a metal material, the nuclear steam supply cassette 21 having a compact structure and ensuring a sufficient structural strength. Can be further reduced in weight. As a result, the transportation of the nuclear steam supply cassette 21 containing the fuel to the installation site of the packaged reactor 20 is further facilitated.
Further, since the steam generator 23 is built in the nuclear steam supply cassette 21, piping for transporting the primary coolant is unnecessary, so that the primary coolant main steam pipe and the primary coolant main water supply pipe are transported. There is no need for equipment in case of a break in the piping.
Further, since the shielding water 36 is used as a shielding material for shielding neutrons and gamma rays radiated from the core 24 in the cassette without using a concrete material or the like, the radiation removal treatment for the radioactive shielding material is performed. For easy post-processing.
[0017]
On the other hand, when the steam generator 23 loses the slow heat function, the emergency cooling water supply valve 38 and the pressure reducing valve 40 are automatically opened, and the shielding water 36 is poured into the nuclear steam supply cassette 21 from the water shielding tank 35. The core 24 in the cassette is gradually heated.
Therefore, even if the primary cooling system is hindered, emergency cooling of the nuclear steam supply cassette 21 can be performed with simple equipment.
In addition, since the shielding water 36 that shields neutrons and gamma rays radiated from each cassette core 24 during normal operation of the reactor 20 can be used for emergency cooling of the cassette core 24, the equipment can be simplified. Can be further improved.
[0018]
The present invention described above is not limited to the above, and can be implemented with appropriate modifications.
As shown in FIG. 2, the height of the liquid level of the primary coolant 28 filled in the nuclear steam supply cassette 21 according to the embodiment is the position of H1, but the level of the liquid level of the primary coolant 28 is The height may be set at H2 so that the upper portion of the steam generator 23 is exposed. In this case, heat exchange is performed between the primary coolant and the secondary coolant by liquid natural convection and boiling steam.
Alternatively, the liquid level of the primary coolant 28 may be set at the position H3 so that the steam generator 23 is entirely exposed. In this case, heat exchange is performed with the secondary coolant by the primary coolant that has become boiling steam.
The pressure pipe liner 25 constituting the lining of the pressure pipe 22 may use Zircaloy instead of stainless steel. This further reduces neutron absorption in the pressure tube.
[0019]
Moreover, it can replace with the nuclear steam supply cassette 21 which concerns on embodiment mentioned above, and can also use the nuclear steam supply cassette 51 as shown in FIG.
The nuclear steam supply cassette 51 is obtained by adding a pump 52 to the bottom of the pressure pipe 22 with respect to the nuclear steam supply cassette 21. Thereby, the primary coolant 28 in the nuclear steam supply cassette 51 can be circulated efficiently, and the heat exchange efficiency of the steam generator 23 is improved.
Further, in the embodiment described above, a plurality of nuclear steam supply cassettes 21 are arranged in the moderator tank 31, but one nuclear steam supply cassette is provided in the moderator tank 31 according to the desired power generation amount. Only 21 may be arranged.
[0020]
【The invention's effect】
As described above, according to the present invention, the nuclear steam which is provided with the core in the cassette made of the fuel body and the steam generator inside the pressure pipe, and is configured so that the control rod can be arranged outside the pressure pipe. With the supply cassette, it is possible to provide a packaged nuclear reactor that can be used in a nuclear power plant as a non-network power source that is not connected to the power grid.
[Brief description of the drawings]
FIG. 1 is an elevational sectional view showing a structure of a nuclear steam supply cassette according to an embodiment of the present invention.
FIG. 2 is an elevational sectional view showing a structure of a packaged nuclear reactor using the nuclear steam supply cassette according to the embodiment.
FIG. 3 is a plan sectional view showing the structure of a packaged nuclear reactor using the nuclear steam supply cassette according to the embodiment.
FIG. 4 is an elevational sectional view showing the structure of a nuclear steam supply cassette according to another embodiment of the present invention.
FIG. 5 is a diagram showing a configuration of a conventional integrated nuclear reactor.
FIG. 6 is a diagram showing a configuration of a conventional pressure tube reactor.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 20 ... Package type reactor, 21,51 ... Nuclear steam supply cassette, 22 ... Pressure pipe, 23 ... Steam generator, 24 ... Core in cassette, 26 ... Reinforcement fiber layer, 30 ... Moderator, 32 ... Control rod, 35 ... shielding water, 36 ... water shielding tank, 38 ... emergency cooling water supply valve, 40 ... pressure reducing valve.

Claims (7)

A pressure tube;
Inside the pressure tube, a cassette core consisting of a fuel body and a steam generator are provided,
A nuclear steam supply cassette capable of disposing a control rod outside the pressure pipe. The nuclear steam supply cassette according to claim 1, wherein the pressure pipe includes a reinforcing fiber layer on an outer periphery. The nuclear steam supply cassette according to claim 1 or 2, further comprising a pressure reducing valve that communicates with the inside of the pressure pipe outside the pressure pipe. A packaged nuclear reactor in which a plurality of the nuclear steam supply cassettes according to any one of claims 1 to 3 are arranged at intervals. The packaged nuclear reactor according to claim 4, wherein a moderator and a control rod are provided between the plurality of nuclear steam supply cassettes. The packaged nuclear reactor according to claim 4 or 5, further comprising a water shielding tank for storing shielding water supplied in the nuclear steam supply cassette. The packaged nuclear reactor according to claim 6, further comprising an emergency cooling water supply valve that communicates with the inside of the pressure pipe and the inside of the water shielding tank outside the pressure pipe.

Images