JP7453062B2 - nuclear power plant - Google Patents

Description

The present invention relates to a nuclear power plant, particularly a boiling water type nuclear power plant.

A boiling water nuclear power plant (hereinafter simply referred to as a "nuclear power plant") mainly includes a reactor building where a nuclear reactor is housed and a turbine building where a steam turbine for generating electricity is housed. ing. Further, a nuclear power plant includes a reactor containment vessel inside a nuclear reactor building, and a reactor pressure vessel inside this reactor containment vessel.

A nuclear power plant uses energy generated in a reactor core loaded with fuel assemblies inside the reactor pressure vessel to boil water inside the reactor pressure vessel and generate steam. A nuclear power plant generates electricity by guiding generated steam to a steam turbine inside a turbine building through main steam piping and rotating the steam turbine with the steam. In a nuclear power plant, steam that has passed through a steam turbine is guided to the main condenser, where it is cooled and condensed by heat transfer tubes inside the main condenser and returned to water. In addition, in a nuclear power plant, water in the main condenser is returned to the inside of the reactor pressure vessel via a water supply pipe using a condensate pump and a water supply pump.

In the unlikely event that a loss of coolant accident such as a rupture of the main steam pipe occurs in a nuclear power plant, the pressure inside the reactor containment vessel will rise due to the steam released inside the reactor containment vessel, causing overload. There is a concern that this could lead to pressure conditions.

Therefore, for example, nuclear power plants described in Patent Document 1 and Patent Document 2 are provided. The nuclear power plant described in Patent Document 1 condenses steam released inside the reactor containment vessel in a pressure suppression pool installed inside the reactor containment vessel, and also converts water in the main condenser into nuclear reactors. It is designed to spray water into the reactor containment vessel to condense steam and suppress the pressure rise inside the reactor containment vessel. In addition, the nuclear power plant described in Patent Document 2 provides an outer pool outside the reactor containment vessel, and exchanges heat between the water in the outer pool and the wall surface of the reactor containment vessel, thereby generating steam inside the reactor containment vessel. This structure condenses the reactor and suppresses the rise in pressure inside the reactor containment vessel.

Japanese Patent Application Publication No. 2015-197394 Japanese Patent Application Publication No. 4-125495

However, when providing a nuclear power plant with a compact and economical reactor containment vessel without a pressure suppression pool, for example, when a loss of coolant accident occurs, the volume of the reactor containment vessel is small, so the reactor containment vessel The inside of the unit may become overpressured in a short period of time. In such nuclear power plants, the time it takes for the inside of the reactor containment vessel to reach an overpressure state is longer than the time it takes to start suppressing the pressure rise inside the reactor containment vessel with spray water injection or peripheral pools. It may be shorter.

In order to prevent the inside of the reactor containment vessel from becoming overpressurized, nuclear power plants vent the gas inside the reactor containment vessel to the atmosphere through a filter. This allows nuclear power plants to protect the reactor containment vessel and minimize the release of gas containing radioactive materials into the atmosphere. However, it is desirable to avoid venting because it releases gas containing radioactive materials into the atmosphere, albeit in small amounts.

The present invention has been made to solve the above-mentioned problems, and is a nuclear power plant that prevents the inside of the reactor containment vessel from becoming overpressured even if a loss of coolant accident occurs. The main purpose is to provide The purpose of solving other problems will be explained as appropriate in the detailed description.

In order to achieve the above object, the present invention provides a nuclear power plant that includes a reactor pressure vessel for accommodating a reactor core, a reactor containment vessel for storing the reactor pressure vessel, and a reactor containment vessel for accommodating the reactor containment vessel. a nuclear reactor building, a steam turbine housed inside a turbine building disposed outside the reactor building and driven by receiving steam generated inside the reactor pressure vessel; and the nuclear reactor. A main steam pipe that connects the pressure vessel and the steam turbine, a main condenser that condenses steam discharged from the steam turbine, and a turbine bypass pipe that connects the main steam pipe and the main condenser. , a condensing pump and water supply piping that return water generated in the main condenser to the reactor pressure vessel, and connecting the reactor containment vessel and the main condenser, or connecting the reactor containment vessel and the The reactor building includes a steam evacuation pipe that connects the turbine bypass pipe to the reactor building, and an outer circumferential pool that is disposed in the outer peripheral portion of the reactor containment vessel and that stores water, is provided with one or more valves , and the steam evacuation piping is arranged so that at least a portion thereof passes through the inside of the peripheral pool .
Other means will be described later.

According to the present invention, even if a loss of coolant accident occurs, it is possible to prevent the inside of the reactor containment vessel from becoming overpressurized.

FIG. 1 is a schematic configuration diagram of a nuclear power plant according to a first embodiment. FIG. 2 is a schematic configuration diagram of a nuclear power plant according to a second embodiment. FIG. 3 is a schematic configuration diagram of a nuclear power plant according to a third embodiment. FIG. 3 is a schematic configuration diagram of a nuclear power plant according to a fourth embodiment. It is a schematic block diagram of the nuclear power plant based on 5th Embodiment. It is a schematic block diagram of the nuclear power plant based on 6th Embodiment. It is a schematic block diagram of the nuclear power plant based on 7th Embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention (hereinafter referred to as "this embodiment") will be described in detail below with reference to the drawings. The figures are only shown schematically to provide a thorough understanding of the invention. Therefore, the present invention is not limited to the illustrated example. Further, in each figure, common or similar components are denoted by the same reference numerals, and redundant explanation thereof will be omitted.

[First embodiment]
In the first embodiment, even if a loss of coolant accident occurs and the pressure inside the reactor containment vessel increases in a short time, the inside of the reactor containment vessel will be in an overpressure state. It is intended to provide a nuclear power plant that avoids the release of gases containing radioactive materials into the atmosphere.

<Nuclear power plant configuration>
Hereinafter, with reference to FIG. 1, the configuration of a nuclear power plant 1000 according to the first embodiment will be described. FIG. 1 is a schematic configuration diagram of a nuclear power plant 1000 according to the first embodiment. This embodiment will be described assuming that the nuclear power plant 1000 is a boiling water type plant.

As shown in FIG. 1, a nuclear power plant 1000 according to the first embodiment includes a reactor building 1 in which a nuclear reactor is housed, and a turbine building 2 in which a steam turbine for generating electricity is housed.

The nuclear power plant 1000 includes a reactor containment vessel 3 inside a reactor building 1 and a reactor pressure vessel 4 inside the reactor containment vessel 3 . Inside the reactor pressure vessel 4, a reactor core 5 loaded with fuel assemblies is housed. Inside the reactor containment vessel 3, a dry well 6 is provided around the reactor pressure vessel 4. The reactor pressure vessel 4 is supported by a structure (not shown) installed inside the reactor containment vessel 3. In this embodiment, the nuclear power plant 1000 includes an outer peripheral pool 21 outside the reactor containment vessel 3 . However, the outer circumferential pool 21 is not necessarily essential and can be deleted.

The nuclear power plant 1000 also includes a high-pressure turbine 10, a moisture separator 11, a low-pressure turbine 12, a generator 13, a main condenser 14, and a condensate pump 17a inside the turbine building 2. A water supply pump 17b is provided.

The nuclear power plant 1000 uses energy generated in the reactor core 5 inside the reactor pressure vessel 4 to boil water inside the reactor pressure vessel 4 to generate (generate) steam. Steam generated inside the reactor pressure vessel 4 is sent to the turbine building 2 through the main steam pipe 7 and flows into the high-pressure turbine 10 (steam turbine). The main steam pipe 7 is a pipe that connects the reactor pressure vessel 4 and the high pressure turbine 10. A main steam isolation valve 8 for isolating the portion of the main steam pipe 7 on the reactor containment vessel 3 side and a main steam stop valve 9 for stopping the flow of steam are provided on the route of the main steam pipe 7. It is being

The steam that has passed through the high pressure turbine 10 passes through the moisture separator 11 and flows into the low pressure turbine 12 . A generator 13 is connected to the shafts of the high pressure turbine 10 and the low pressure turbine 12. The nuclear power plant 1000 generates electricity using a generator 13 by rotating a high-pressure turbine 10 and a low-pressure turbine 12 using steam.

Steam that has passed through the low pressure turbine 12 flows into the main condenser 14. The nuclear power plant 1000 includes a heat exchanger 16 inside the main condenser 14 . The heat exchanger 16 exchanges heat between the steam passing through the main condenser 14 and the seawater passing through the heat exchanger 16 . The nuclear power plant 1000 also includes a circulating water pump 15 outside the turbine building 2. The circulating water pump 15 draws seawater from the sea and circulates it inside the heat exchanger 16.

In the nuclear power plant 1000, steam discharged from the low pressure turbine 12 to the main condenser 14 is heat exchanged with seawater in the heat exchanger 16. Thereby, the nuclear power plant 1000 condenses the steam discharged from the low pressure turbine 12 to the main condenser 14 and returns it to water. Water condensed from steam inside the main condenser 14 is pressurized by a condensate pump 17a and a water supply pump 17b, and is returned to the inside of the reactor pressure vessel 4 through a water supply pipe 18.

A turbine bypass pipe 19 for bypassing and guiding steam from the main steam pipe 7 to the main condenser 14 is connected to an intermediate portion of the main steam pipe 7 . The turbine bypass piping 19 has one end connected to an intermediate portion of the main steam piping 7 and the other end disposed inside the main condenser 14 . A turbine bypass valve 20 is provided on the path of the turbine bypass piping 19 to control the flow (flow rate) of steam.

In this embodiment, the nuclear power plant 1000 includes a steam escape pipe 101 (steam escape pipe) that connects the dry well 6 of the reactor containment vessel 3 and the main condenser 14. The steam evacuation pipe 101 is a pipe for escaping steam from the inside of the reactor containment vessel 3 to the outside in the event that a loss of coolant accident occurs. In the nuclear power plant 1000, even if a loss of coolant accident occurs and the pressure inside the reactor containment vessel 3 increases in a short period of time, the steam evacuation piping 101 prevents the inside of the reactor containment vessel 3 from rising. By releasing steam to the outside, it is possible to prevent the inside of the reactor containment vessel 3 from becoming overpressurized. In addition, in this embodiment, the steam evacuation pipe 101 is arranged so that at least a portion thereof passes through the inside of the outer circumferential pool 21.

At least one valve (sealing valve 110) for stopping the flow of steam is provided on the path of the steam escape piping 101. For example, in this embodiment, two sealing valves 110a and 110b are provided on the path of the steam escape piping 101. The sealing valve 110a is a valve provided near the inner end of the dry well 6 of the reactor containment vessel 3 on the path of the steam evacuation pipe 101. The sealing valve 110b is a valve provided between the reactor containment vessel 3 and the main condenser 14 on the path of the steam escape piping 101. The sealing valve 110b is provided outside the main condenser 14 and at a position near the main condenser 14. However, the sealing valve 110a can be provided outside the reactor containment vessel 3. Further, the sealing valve 110b can be provided inside the main condenser 14.

Preferably, the sealing valve 110 opens at a pressure equal to or higher than the specified pressure (for example, a pressure equal to or higher than 0.4 MPa when the design pressure (maximum working pressure) of the reactor containment vessel 3 is 0.4 MPa), and opens at a pressure lower than the specified value. It is best to configure it with a safety valve (pressure-operated valve) that closes with pressure. Thereby, when the pressure inside the reactor containment vessel 3 decreases, the sealing valve 110 is closed, so that the amount of gas released from the reactor containment vessel 3 to the main condenser 14 can be suppressed to a minimum. Note that the sealing valve 110b on the main condenser 14 side may function as a check valve.

In such a configuration, the nuclear power plant 1000 is configured such that, if a coolant loss accident occurs such as a rupture of the main steam pipe 7 inside the reactor containment vessel 3, the nuclear power plant 1000 can Steam flows out from the reactor pressure vessel 4 into the reactor containment vessel 3 . At this time, steam also flows back from the high-pressure turbine 10 side to the break port side of the main steam pipe 7, but the back flow is stopped by closing the main steam isolation valve 8 and the main steam stop valve 9.

As steam flows out from the reactor pressure vessel 4 into the reactor containment vessel 3 through the break in the main steam pipe 7, the pressure inside the reactor containment vessel 3 increases.

When the pressure inside the reactor containment vessel 3 reaches a specified pressure or higher, the sealing valve 110a and the sealing valve 110b open, and the pressure difference between the reactor containment vessel 3 and the main condenser 14 causes the reactor containment to close. Gas inside the vessel 3 (steam and nitrogen gas present inside the reactor containment vessel 3) flows into the main condenser 14.

For example, in a nuclear power plant 1000 where the design pressure (maximum working pressure) of the reactor containment vessel 3 is 0.4 MPa and the inside of the main condenser 14 is evacuated, suppose that the reactor containment vessel 3 is Assume that a coolant loss accident occurs such as the main steam pipe 7 rupturing internally. In this case, the pressure inside the reactor containment vessel 3 increases due to the outflow of steam from the reactor pressure vessel 4 into the reactor containment vessel 3 through the break port of the main steam pipe 7. As a result, the pressure difference between the reactor containment vessel 3 and the main condenser 14 is sufficient to transfer gas from the reactor containment vessel 3 to the main condenser 14. The sealing valve 110a and the sealing valve 110b open until the pressure exceeds 0.4 MPa, which is the design pressure (maximum working pressure) of the reactor containment vessel 3, and reaches a pressure twice the design pressure. Thereby, the nuclear power plant 1000 can avoid the inside of the reactor containment vessel 3 from becoming overpressured in a short period of time immediately after the occurrence of a loss of coolant accident. Moreover, in the present embodiment, the nuclear power plant 1000 cools the reactor containment vessel 3 with the outer peripheral pool 21, so even if the main steam isolation valve 8 is delayed in closing, the reactor containment vessel 3 is cooled. It is possible to avoid overpressure inside for a long time.

Note that the present embodiment has been described assuming that a coolant loss accident occurs due to the main steam pipe 7 breaking inside the reactor containment vessel 3. However, the nuclear power plant 1000 is not particularly limited to such a case, and similar effects can be obtained as long as an event that pressurizes the inside of the reactor containment vessel 3 occurs.

Furthermore, in this embodiment, the steam evacuation pipe 101 has one end disposed in the dry well 6 of the reactor containment vessel 3 and the other end disposed inside the main condenser 14. The position of the other end of the steam evacuation pipe 101 is not particularly limited, and it may be placed in either the gas phase or the liquid phase inside the main condenser 14.

<Main features of nuclear power plants>
(1) As shown in FIG. 1, a nuclear power plant 1000 according to the present embodiment includes a reactor pressure vessel 4 housing a reactor core 5, a reactor containment vessel 3 housing the reactor pressure vessel 4, and a nuclear reactor It is housed inside a reactor building 1 that houses a containment vessel 3 and a turbine building 2 located outside the reactor building 1, and is driven by receiving steam generated inside the reactor pressure vessel 4. A main steam pipe 7 that connects the reactor pressure vessel 4 and the steam turbine (high pressure turbine 10), and a main steam turbine that condenses the steam discharged from the steam turbine (high pressure turbine 10). Water device 14, turbine bypass piping 19 that connects main steam piping 7 and main condenser 14, condensate pump 17a that returns water generated in main condenser 14 to reactor pressure vessel 4, and water supply piping 18, and a steam evacuation pipe 101 that connects the reactor containment vessel 3 and the main condenser 14. The steam escape piping 101 is provided with one or more valves (sealing valves 110). The valve (sealing valve 110) stops the flow of steam through the steam escape piping 101.

Such a nuclear power plant 1000 allows the gas inside the reactor containment vessel 3 to flow into the liquid phase of the main condenser 14 through the steam escape pipe 101, thereby promoting condensation of the steam in the gas that has flowed in. , pressure rise inside the main condenser 14 can be suppressed. Thereby, the nuclear power plant 1000 can increase the depressurization effect inside the reactor containment vessel 3. As a result, in the nuclear power plant 1000, even if a loss of coolant accident occurs and the pressure inside the reactor containment vessel 3 increases in a short period of time, the steam evacuation piping 101 allows the nuclear power plant 1000 to By releasing steam from the inside of the reactor containment vessel 3 to the outside, it is possible to prevent the inside of the reactor containment vessel 3 from becoming overpressurized.

(2) In the nuclear power plant 1000 according to the present embodiment, valves (sealing valves 110) is provided.

In such a nuclear power plant 1000, if a loss of coolant accident occurs, the sealing valve 110 on the reactor containment vessel 3 side (in this embodiment, the sealing valve 110a) and the sealing valve on the main steam pipe 7 side will be removed. The flow of steam flowing out from the reactor containment vessel 3 to the main steam pipe 7 can be stopped by the stop valve 110 (in this embodiment, the stop valve 110b).

(3) The nuclear power plant 1000 according to the present embodiment includes, inside the reactor building 1, an outer circumferential pool 21 that is arranged on the outer circumferential portion of the reactor containment vessel 3 and that stores water. The steam evacuation pipe 101 is arranged so that at least a portion thereof passes through the inside of the outer circumferential pool 21.

In such a nuclear power plant 1000, the reactor containment vessel 3 is cooled by the outer pool 21, so even if the main steam isolation valve 8 is delayed in closing, the inside of the reactor containment vessel 3 will not be overpressured. You can avoid this situation for a long time.

[Second embodiment]
Hereinafter, with reference to FIG. 2, a nuclear power plant 1000A according to the second embodiment will be described. FIG. 2 is a schematic diagram showing the configuration of a nuclear power plant 1000A according to the second embodiment.

As shown in FIG. 2, compared to the nuclear power plant 1000 of the first embodiment (see FIG. 1), the nuclear power plant 1000A according to the second embodiment has a steam evacuation pipe 101a instead of the steam evacuation pipe 101. They differ in terms of preparation.

The steam evacuation pipe 101a is a pipe arranged so that a portion passing through the inside of the outer circumferential pool 21 extends in the vertical direction. Therefore, in the nuclear power plant 1000A according to the present embodiment, the steam evacuation pipe 101a drawn out from the reactor containment vessel 3 is arranged along the vertical direction inside the outer peripheral pool 21.

Such a nuclear power plant 1000A has the same effect as the nuclear power plant 1000 of the first embodiment (see FIG. 1) (that is, in order to cool the reactor containment vessel 3 in the outer peripheral pool 21, the main steam isolation valve 8 Even if the closure of the nuclear reactor containment vessel 3 is delayed, an overpressure state inside the reactor containment vessel 3 can be avoided for a long time. Moreover, the nuclear power plant 1000A can promote heat exchange between the water in the outer pool 21 and the steam inside the steam evacuation pipe 101a, promote depressurization of the reactor containment vessel 3, and prevent the rise in water temperature of the outer pool 21. Therefore, the time required for the water in the outer pool 21 to start boiling can be shortened.

The form of heat transfer from the reactor containment vessel 3 to the water in the outer peripheral pool 21 is that heat is removed by natural convection heat transfer from the time when the temperature of the water in the outer peripheral pool 21 starts to rise until it boils. After the water boils, heat is removed by nucleate boiling heat transfer. Heat removal by nucleate boiling heat transfer after the water in the peripheral pool 21 boils uses latent heat of vaporization, so the amount of heat removed is larger than heat removal by natural convection heat transfer. Therefore, the nuclear power plant 1000A can suppress the temperature inside the reactor containment vessel 3 from increasing if the time required for the water in the peripheral pool 21 to start boiling can be shortened. In other words, in the nuclear power plant 1000A, if a loss of coolant accident occurs, the time required to obtain a cooling effect by removing heat using latent heat of vaporization with the water in the peripheral pool 21, which has a large amount of heat removed, can be shortened.

[Third embodiment]
Hereinafter, with reference to FIG. 3, a nuclear power plant 1000B according to a third embodiment will be described. FIG. 3 is a schematic diagram showing the configuration of a nuclear power plant 1000B according to the third embodiment.

As shown in FIG. 3, compared to the nuclear power plant 1000 of the first embodiment (see FIG. 1), the nuclear power plant 1000B according to the third embodiment has a steam evacuation pipe 101b instead of the steam evacuation pipe 101. They differ in terms of preparation.

The steam evacuation pipe 101b is a pipe arranged to connect the reactor containment vessel 3 and the turbine bypass pipe 19. Therefore, in the nuclear power plant 1000B according to this embodiment, the end of the steam evacuation pipe 101b is connected to the reactor containment vessel 3 and the turbine bypass pipe 109.

Such a nuclear power plant 1000B can share the steam evacuation pipe 101b and the turbine bypass pipe 19, and has the same effect as the nuclear power plant 1000 of the first embodiment (see FIG. In order to cool the reactor containment vessel 3, even if the closing of the main steam isolation valve 8 is delayed, an overpressure state inside the reactor containment vessel 3 can be avoided for a long time. be able to. Furthermore, the nuclear power plant 1000B can reduce the amount of piping and reduce manufacturing costs.

[Fourth embodiment]
Hereinafter, with reference to FIG. 4, a nuclear power plant 1000C according to a fourth embodiment will be described. FIG. 4 is a schematic diagram showing the configuration of a nuclear power plant 1000C according to the fourth embodiment.

As shown in FIG. 4, in the nuclear power plant 1000C according to the fourth embodiment, compared to the nuclear power plant 1000 of the first embodiment (see FIG. 1), the steam evacuation pipe 101 is located at the inner end of the main condenser 14. It is different in that it has a quencher 1100 in the section. The quencher 1100 is a device for diffusing steam and efficiently condensing the steam inside the pool.

The nuclear power plant 1000 (see FIG. 1) of the first embodiment described above allows the gas inside the reactor containment vessel 3 to flow into the liquid phase of the main condenser 14 through the steam evacuation pipe 101, thereby reducing the amount of gas that has flowed into the reactor containment vessel 3. By promoting condensation of the steam therein, it is possible to suppress a rise in pressure inside the main condenser 14. Thereby, the nuclear power plant 1000 of the first embodiment can increase the depressurizing effect inside the reactor containment vessel 3. However, in the nuclear power plant 1000 of the first embodiment, there is a possibility that a load is applied to the main condenser 14 due to pressure waves generated during vapor bubble condensation.

In contrast, in the nuclear power plant 1000C according to the fourth embodiment, a quencher 1100 provided at the inner end of the main condenser 14 of the steam evacuation pipe 101 prevents the flow of steam bubbles to the main condenser 14. The structure is such that the inlets are dispersed to subdivide the vapor bubbles. Thereby, the nuclear power plant 1000C according to the fourth embodiment can minimize (reduce) the load applied to the main condenser 14 due to the pressure waves generated during vapor bubble condensation.

Such a nuclear power plant 1000C has the same effect as the nuclear power plant 1000 of the first embodiment (see FIG. 1) (that is, in order to cool the reactor containment vessel 3 in the outer peripheral pool 21, the main steam isolation valve 8 Even if the closure of the nuclear reactor containment vessel 3 is delayed, an overpressure state inside the reactor containment vessel 3 can be avoided for a long time. Moreover, the nuclear power plant 1000C can enhance the steam condensation effect, suppress the pressure amplitude inside the main condenser 14, and improve safety.

[Fifth embodiment]
Hereinafter, with reference to FIG. 5, a nuclear power plant 1000D according to a fifth embodiment will be described. FIG. 5 is a schematic diagram showing the configuration of a nuclear power plant 1000D according to the fifth embodiment.

As shown in FIG. 5, a nuclear power plant 1000D according to the fifth embodiment differs from the nuclear power plant 1000 (see FIG. 1) of the first embodiment mainly in the following points.
(1) Instead of the steam escape pipe 101, a steam escape pipe 102 and a turbine return pipe 503 are provided.
(2) The turbine 502 is provided between the steam escape pipe 102 and the turbine return pipe 503.
(3) A water storage tank 504, an in-core water injection pipe 505, and a tank water supply pipe 506 are provided between the portion of the water supply pipe 18 between the condensate pump 17a and the water supply pump 17b and the reactor pressure vessel 4. point.

The steam evacuation pipe 102 is a pipe that guides the gas inside the reactor containment vessel 3 to the turbine 502 in the event that a loss of coolant accident occurs. The steam evacuation pipe 102 is connected to the dry well 6 of the reactor containment vessel 3 and the turbine 502 of the turbine-driven pump 501.

The turbine return pipe 503 is a pipe that guides the gas that has passed through the turbine 502 to the main condenser 14. Turbine return pipe 503 is connected to turbine 502 and main condenser 14 .

At least one valve (sealing valve 120) for stopping the flow of steam is provided on the path between the steam escape pipe 102 and the turbine return pipe 503. For example, in this embodiment, a sealing valve 120a is provided on the path of the steam evacuation pipe 102 near the inner end of the dry well 6 of the reactor containment vessel 3. Further, on the path of the turbine return pipe 503, a sealing valve 120b is provided near the outside of the main condenser 14. However, the sealing valve 120a can be provided outside the reactor containment vessel 3. Further, the sealing valve 120b can be provided inside the main condenser 14.

A turbine-driven pump 501 arranged on the path of an in-furnace water injection pipe 505 is connected to the shaft of the turbine 502 . The turbine 502 is designed to prevent gas inside the reactor containment vessel 3 from flowing out into the main condenser 14 via the steam escape pipe 102 and the turbine return pipe 503 in the event that a loss of coolant accident occurs. The rotation drives the turbine-driven pump 501. The turbine-driven pump 501 sends water stored in the water storage tank 504 into the reactor containment vessel 3 to cool the inside of the reactor containment vessel 3 . Such a nuclear power plant 1000D makes it possible to inject water into the inside of the reactor pressure vessel 4 even if a loss of coolant accident occurs.

The water storage tank 504 is a tank that stores water to be injected into the reactor pressure vessel 4 .

The in-core water injection pipe 505 is a pipe that guides water stored in the water storage tank 504 into the inside of the reactor pressure vessel 4 . On the route of the in-reactor water injection pipe 505, there is a turbine-driven pump 501 for sending the water stored in the water storage tank 504 into the inside of the reactor containment vessel 3, and a flow of water sent into the inside of the reactor containment vessel 3. A water injection valve 508 for controlling the water is provided.

The tank water supply pipe 506 is a pipe that guides a portion of the water condensed in the main condenser 14 to the water storage tank 504. A water supply valve for controlling the flow of water led to the water storage tank 504 is provided on the route of the tank water supply pipe 506.

In the nuclear power plant 1000D, water can be injected into the water storage tank 504 through a tank water supply pipe 506 branched from the water supply pipe 18 downstream of the condensate pump 17a. Note that the nuclear power plant 1000D can control the water level inside the water storage tank 504 by opening and closing the water supply valve 507 to the water storage tank 504.

If a loss of coolant accident occurs, the nuclear power plant 1000D causes the gas inside the dry well 6 to flow into the turbine 502 via the steam escape pipe 102. Thereby, the nuclear power plant 1000D rotates the turbine 502 and drives the turbine-driven pump 501. Then, the nuclear power plant 1000D uses the turbine-driven pump 501 to send the water inside the water storage tank 504 into the inside of the reactor pressure vessel 4 through the in-core water injection pipe 505. Thereby, the nuclear power plant 1000D can inject water into the inside of the reactor pressure vessel 4. Note that the gas exhausted from the turbine 502 returns to the main condenser 14 through a turbine return pipe 503.

Such a nuclear power plant 1000D has the same effect as the nuclear power plant 1000 of the first embodiment (see FIG. 1) (i.e., in order to cool the reactor containment vessel 3 in the outer peripheral pool 21, the main steam isolation Even if the closing of the valve 8 is delayed, an overpressure state inside the reactor containment vessel 3 can be avoided for a long period of time. Moreover, in the nuclear power plant 1000D, water can be injected into the reactor core 5 inside the reactor pressure vessel 4, and the time for the water level to fall inside the reactor pressure vessel 4 can be extended. It is possible to avoid overpressure inside the unit for a long time.

Further, in the nuclear power plant 1000D, valves (sealing valves 120) are provided at least in the inner part of the reactor containment vessel 3 of the steam escape pipe 102 and the outer part of the main condenser 14 of the turbine return pipe 503. There is.

In such a nuclear power plant 1000D, if a loss of coolant accident occurs, the sealing valve 120 on the reactor containment vessel 3 side (in this embodiment, the sealing valve 120a) and the sealing valve on the main steam pipe 7 side The flow of steam flowing out from the reactor containment vessel 3 to the main steam pipe 7 can be stopped by the stop valve 120 (in this embodiment, the seal valve 120b).

[Sixth embodiment]
Hereinafter, with reference to FIG. 6, a nuclear power plant 1000E according to a sixth embodiment will be described. FIG. 6 is a schematic diagram showing the configuration of a nuclear power plant 1000E according to the sixth embodiment.

As shown in FIG. 6, compared to the nuclear power plant 1000D according to the fifth embodiment (see FIG. 5), the nuclear power plant 1000E according to the sixth embodiment has a water injection pipe 700 instead of the in-core water injection pipe 505. They differ in terms of preparation.

The water injection pipe 700 is a pipe that connects the water storage tank 504 and the dry well 6 inside the reactor containment vessel 3. The water injection pipe 700 has a turbine-driven pump 501 on its path. Further, the water injection pipe 700 has a spray sparger 701 at the inner end of the reactor containment vessel 3. The spray sparger 701 is a dispersion tube for spraying water.

In the nuclear power plant 1000E, if a loss of coolant accident occurs, the gas inside the dry well 6 flows into the turbine 502 via the steam escape pipe 102. Thereby, the nuclear power plant 1000E rotates the turbine 502 and drives the turbine-driven pump 501. Then, the nuclear power plant 1000E uses the turbine-driven pump 501 to send water inside the water storage tank 504 to the dry well 6 through the water injection pipe 700. Thereby, the nuclear power plant 1000E can inject water into the dry well 6. Note that the gas exhausted from the turbine 502 returns to the main condenser 14 through a turbine return pipe 503.

Such a nuclear power plant 1000E has the same effect as the nuclear power plant 1000D of the fifth embodiment (see FIG. 5) (i.e., in order to cool the reactor containment vessel 3 in the outer peripheral pool 21, the main steam isolation Even if the closing of the valve 8 is delayed, an overpressure state inside the reactor containment vessel 3 can be avoided for a long period of time. Moreover, since the nuclear power plant 1000E can inject cooling water into the inside of the dry well 6, the pressure inside the reactor containment vessel 3 can be reduced.

Moreover, the nuclear power plant 1000E can efficiently condense the steam inside the dry well 6 by the spray sparger 701 provided at the end of the water injection pipe 700.

[Seventh embodiment]
Hereinafter, with reference to FIG. 7, a nuclear power plant 1000F according to a seventh embodiment will be described. FIG. 7 is a schematic diagram showing the configuration of a nuclear power plant 1000F according to the seventh embodiment.

As shown in FIG. 7, the nuclear power plant 1000F according to the seventh embodiment is different from the nuclear power plant 1000E (see FIG. 6) according to the sixth embodiment in the following points.
(1) A heat exchanger 900 is provided inside the reactor containment vessel 3.
(2) The spray sparger 701 is removed from the end of the water injection pipe 700, and the water injection pipe 700 is connected to the heat exchanger 900.
(3) A cooling water return pipe 901 connected to the heat exchanger 900 and the main condenser 14 is provided.

In the nuclear power plant 1000F, if a coolant loss accident occurs, the gas inside the dry well 6 flows into the turbine 502 via the steam escape pipe 102. Thereby, the nuclear power plant 1000F rotates the turbine 502 and drives the turbine-driven pump 501. Then, in the nuclear power plant 1000F, the turbine-driven pump 501 sends the water inside the water storage tank 504 to the heat exchanger 900 through the water injection pipe 700. Thereby, the nuclear power plant 1000E can inject water into the heat exchanger 900. The water sent to the heat exchanger 900 exchanges heat with the steam inside the reactor containment vessel 3. Thereby, the nuclear power plant 1000F lowers the temperature inside the reactor containment vessel 3. Note that the gas exhausted from the turbine 502 returns to the main condenser 14 through a turbine return pipe 503. Further, the water that has undergone heat exchange with the steam inside the reactor containment vessel 3 is returned to the main condenser 14 from the heat exchanger 900 through the cooling water return pipe 901.

The reason for returning the water that has undergone heat exchange with the steam inside the reactor containment vessel 3 to the main condenser 14 is as follows. That is, the water that has exchanged heat with the steam inside the reactor containment vessel 3 is in a high temperature state. Therefore, if water that has undergone heat exchange with steam is returned to the water storage tank 504, unless a cooling mechanism is provided inside the water storage tank 504, the water temperature inside the water storage tank 504 will rise, and eventually the water temperature inside the water storage tank 504 will rise. The water boils. As a result, when the water that has been heat exchanged with steam is returned to the water storage tank 504, the water temperature inside the water storage tank 504 cannot be kept low, so the heat exchange capacity of the heat exchanger 900 gradually decreases, and the reactor It becomes difficult to lower the temperature inside the container 3. Therefore, in the nuclear power plant 1000F, in order to maintain the heat exchange capacity of the heat exchanger 900 in a high state, it is necessary to return the water that has been heat exchanged with the steam inside the reactor containment vessel 3 to the main condenser 14. preferable.

Such a nuclear power plant 1000F has the same effect as the nuclear power plant 1000E of the sixth embodiment (see FIG. 6) (i.e., in order to cool the reactor containment vessel 3 in the outer peripheral pool 21, the main steam isolation Even if the closing of the valve 8 is delayed, an overpressure state inside the reactor containment vessel 3 can be avoided for a long period of time. Moreover, since the nuclear power plant 1000F can inject cooling water into the heat exchanger 900 inside the reactor containment vessel 3, the pressure inside the reactor containment vessel 3 can be reduced.

The present invention is not limited to the embodiments described above, and includes various modifications. For example, the embodiments described above are described in detail to explain the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the configurations described. It is possible to replace a part of the configuration of the embodiment with other configurations, and it is also possible to add other configurations to the configuration of the embodiment. Furthermore, it is possible to add, delete, or replace a part of each configuration with other configurations.

1 Reactor building 2 Turbine building 3 Reactor containment vessel 4 Reactor pressure vessel 5 Reactor core 6 Drywell 7 Main steam piping 8 Main steam isolation valve 9 Main steam stop valve 10 High pressure turbine (steam turbine)
11 Moisture separator 12 Low pressure turbine 13 Generator 14 Main condenser 15 Circulating water pump 16 Heat exchanger 17a Condensate pump 17b Water supply pump 18 Water supply piping 19 Turbine bypass piping 20 Turbine bypass valve 21 Peripheral pool 22 Water supply isolation valve 101 , 101a, 101b, 102 Steam escape piping (steam escape piping)
110 (110a, 110b), 120 (120a, 120b) Sealing valve (valve)
501 Turbine drive pump 502 Turbine 503 Turbine return piping 504 Water storage tank 505 In-furnace water injection piping 506 Tank water supply piping 507 Water supply valve 508 Water injection valve 700 Water injection piping 701 Spray sparger 900 Heat exchanger 901 Cooling water return piping 1000, 1000A, 1000B, 1000C ,1000D,1000E,1000F Nuclear power plant 1100 Quencher

Claims (8)

a reactor pressure vessel that houses the reactor core;
a reactor containment vessel that stores the reactor pressure vessel;
a reactor building housing the reactor containment vessel;
a steam turbine housed inside a turbine building located outside the reactor building and driven by receiving steam generated inside the reactor pressure vessel;
a main steam pipe connecting the reactor pressure vessel and the steam turbine;
a main condenser that condenses steam discharged from the steam turbine;
a turbine bypass pipe connecting the main steam pipe and the main condenser;
a condensate pump and water supply piping that return water generated in the main condenser to the reactor pressure vessel;
a steam evacuation pipe connecting the reactor containment vessel and the main condenser or connecting the reactor containment vessel and the turbine bypass pipe,
The steam escape piping is provided with one or more valves,
A nuclear power plant, wherein the valve is provided at least in a portion of the steam evacuation piping inside the reactor containment vessel and in a portion of the steam evacuation piping outside the main condenser. a reactor pressure vessel that houses the reactor core;
a reactor containment vessel that stores the reactor pressure vessel;
a reactor building housing the reactor containment vessel;
a steam turbine housed inside a turbine building located outside the reactor building and driven by receiving steam generated inside the reactor pressure vessel;
a main steam pipe connecting the reactor pressure vessel and the steam turbine;
a main condenser that condenses steam discharged from the steam turbine;
a turbine bypass pipe connecting the main steam pipe and the main condenser;
a condensate pump and water supply piping that return water generated in the main condenser to the reactor pressure vessel;
a steam evacuation pipe that connects the reactor containment vessel and the main condenser or connects the reactor containment vessel and the turbine bypass pipe;
The inside of the reactor building includes an outer circumferential pool arranged at an outer circumferential portion of the reactor containment vessel and in which water is stored,
The steam escape piping is provided with one or more valves,
A nuclear power plant, wherein the steam evacuation piping is disposed so that at least a portion thereof passes through the inside of the outer circumferential pool. In the nuclear power plant according to claim 2 ,
A nuclear power plant, wherein a portion of the steam evacuation piping that passes through the outer peripheral pool is arranged to extend in a vertical direction. a reactor pressure vessel that houses the reactor core;
a reactor containment vessel that stores the reactor pressure vessel;
a reactor building housing the reactor containment vessel;
a steam turbine housed inside a turbine building located outside the reactor building and driven by receiving steam generated inside the reactor pressure vessel;
a main steam pipe connecting the reactor pressure vessel and the steam turbine;
a main condenser that condenses steam discharged from the steam turbine;
a turbine bypass pipe connecting the main steam pipe and the main condenser;
a condensate pump and water supply piping that return water generated in the main condenser to the reactor pressure vessel;
a steam evacuation pipe connecting the reactor containment vessel and the main condenser or connecting the reactor containment vessel and the turbine bypass pipe,
The steam escape piping is provided with one or more valves,
A nuclear power plant characterized in that the steam evacuation piping has a quencher for diffusing steam at an inner end of the main condenser. a reactor pressure vessel that houses the reactor core;
a reactor containment vessel that stores the reactor pressure vessel;
a reactor building housing the reactor containment vessel;
a steam turbine housed inside a turbine building located outside the reactor building and driven by receiving steam generated inside the reactor pressure vessel;
a main steam pipe connecting the reactor pressure vessel and the steam turbine;
a main condenser that condenses steam discharged from the steam turbine;
a turbine bypass pipe connecting the main steam pipe and the main condenser;
a condensate pump and water supply piping that return water generated in the main condenser to the reactor pressure vessel;
a water storage tank located outside the reactor building and storing water;
a tank water supply pipe that connects the water storage tank and a water supply pipe on the discharge side of the condensate pump;
a water injection pipe connecting the water storage tank and the reactor pressure vessel;
a turbine-driven pump provided in the water injection pipe;
a turbine return pipe connecting the turbine of the turbine-driven pump and the main condenser;
a steam evacuation pipe connecting the reactor containment vessel and the turbine of the turbine-driven pump,
A nuclear power plant, wherein the steam escape piping and the turbine return piping are provided with one or more valves. In the nuclear power plant according to claim 5 ,
A nuclear power plant, wherein the valve is provided at least in a portion of the steam escape piping inside the reactor containment vessel and in a portion of the turbine return piping outside the main condenser. In the nuclear power plant according to claim 5 or claim 6 ,
A nuclear power plant, wherein the water injection pipe has a spray sparger at an inner end of the reactor containment vessel. In the nuclear power plant according to claim 5 or claim 6 ,
a heat exchanger provided inside the reactor containment vessel;
A cooling water return pipe connecting the heat exchanger and the main condenser,
A nuclear power plant, wherein the water injection pipe connects the water storage tank and a heat exchanger provided inside the reactor containment vessel.

Images