JP2018132399A - Nuclear Power Plant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent vertical extension of a reactor building and heat transmission performance deterioration of a water-cooling system in a nuclear power plant that has a static water-cooling system and an air-cooled system.SOLUTION: A nuclear power plant comprises: a reactor containment vessel housing a pressure vessel; a condensation tank housing an intermediate heat exchanger; an air-cooled heat exchanger that is connected to the intermediate heat exchanger using an air-cooled loop tube and circulates a coolant between the intermediate heat exchanger and the air-cooled heat exchanger to cool and condense vapors introduced in the condensation tank; a water cooling pool located at an upper part of the reactor containment vessel; and a water-cooling heat exchanger that is located in the water cooling pool, introduces vapors remained not condensed in the condensation tank through a separation vapor discharging tube connected to an upper part of the condensation tank, cools and condenses the introduced vapors. The condensation tank is located at a position lower than the positions of the air-cooled heat exchanger and the water-cooling heat exchanger.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a structure of a nuclear power plant, and more particularly to a reactor cooling facility that removes decay heat by a static water cooling system and an air cooling system in the event of an accident.

  As a nuclear reactor cooling facility when power is lost, there is a nuclear power plant in which a static cooling facility using natural force such as gravity is installed. In order to remove the decay heat after the reactor shutdown, the steam in the pressure vessel or containment vessel is drawn into the heat transfer tube installed in the pool where the cooling water is stored and condensed, and the condensed water is stored in the pressure vessel or containment by gravity. A water cooling system for returning to the container is the mainstream.

  In this static reactor cooling equipment, since the condensed water is returned using gravity, the water cooling pool needs to be installed above the pressure vessel or the containment vessel. In addition, the water in the water-cooled pool is boiled and steam is released into the atmosphere to remove heat, so heat removal is not possible when the pool water is depleted, so the capacity of the water-cooled pool is determined according to the required heat removal amount .

  As a background art in this technical field, for example, there is a technique such as Patent Document 1. Patent Document 1 discloses a “reactor cooling system in which steam generated by decay heat is first cooled by air via an air cooling system and then cooled by a cooling pool via a heat exchanger”. .

Japanese Patent No. 6004438

  In the water cooling system, the cooling period is determined by the capacity of the water cooling pool. However, if the water-cooled pool is enlarged, it is necessary to strengthen the seismic structure of the reactor building, which may increase the construction cost of the nuclear power plant.

  On the other hand, an air cooling system that radiates heat to the atmosphere, which is an infinite heat sink, has also been proposed. When air cooling is used, the cooling period becomes infinite, but there is a problem that the heat transfer efficiency of air is small compared to water, and the air cooling heat exchanger becomes large.

  In order to solve these problems, a reactor cooling facility using both a water cooling system and an air cooling system has been proposed. For example, in Patent Document 1, an intermediate heat exchanger of an air cooling system is installed upstream of a water cooling heat exchanger of a water cooling system so that a part of the heat that has been conventionally removed by the water cooling system can be removed by the air cooling system. ing. Since the load of the water cooling system is reduced, the capacity of the water cooling pool can be reduced, or the cooling period can be extended if the capacity of the water cooling pool is the same. Since decay heat decreases with time, if the water cooling system is operated during the period when the decay heat falls to the heat removal capacity of the air cooling system, it can be cooled only by the air cooling system even if the water cooling pool is depleted, and infinite time Can be cooled.

  Generally, in a static air cooling system, a loop thermosyphon heat pipe is used, and the air cooling heat exchanger needs to be installed at a higher position than the intermediate heat exchanger. In Patent Document 1, a condensation tank that is an intermediate heat exchanger is installed in the water-cooled pool, so the air-cooled heat exchanger outside the reactor building is installed at a position higher than the water-cooled pool. Therefore, when the air cooling system is applied, it is necessary to make the reactor building higher than usual, which may increase the construction cost.

  Further, since the intermediate heat exchanger is installed on the upstream side of the water-cooled heat exchanger, the condensed water generated in the intermediate heat exchanger flows into the condensation heat transfer tube of the water-cooled heat exchanger. However, since the condensation heat transfer rate decreases as the condensate film thickness increases, it is desirable not to allow the condensed water from the intermediate heat exchanger to flow into the condensation heat transfer tube.

  Accordingly, the present invention provides a water-cooled heat exchanger having a structure in which a nuclear reactor plant having a static water cooling system and an air cooling system suppresses an increase in the height of a reactor building and separates steam and condensed water with an intermediate heat exchanger. It aims at suppressing the heat-transfer performance fall.

  To achieve the above object, the present invention is connected to a reactor containment vessel containing a pressure vessel, a condensation tank containing an intermediate heat exchanger, the intermediate heat exchanger and an air cooling loop pipe, and the intermediate heat An air-cooled heat exchanger that cools and condenses the steam introduced into the condensing tank by circulating a refrigerant with the exchanger, a water-cooled pool provided on the upper side of the reactor containment vessel, and the water-cooled pool A water-cooled heat exchanger that introduces the steam that remains without being condensed in the condensation tank via a separated steam discharge pipe connected to the upper side of the condensation tank, and cools and condenses the introduced steam. The condensation tank is disposed at a position lower than the air-cooled heat exchanger and the water-cooled heat exchanger.

  The present invention also relates to a reactor containment vessel containing a pressure vessel, a cooling water tank containing an intermediate heat exchanger, steam connected to the cooling water tank by an air cooling loop pipe, and steam introduced from the cooling water tank. An air-cooled heat exchanger for cooling and condensing, a water-cooled pool provided on the upper side of the reactor containment vessel, and a separation steam discharge pipe installed in the water-cooled pool and connected to an outlet header of the intermediate heat exchanger A water-cooled heat exchanger that introduces steam that remains without being condensed in the intermediate heat exchanger and cools and condenses the introduced steam, wherein the cooling water tank is the air-cooled heat exchanger It is arrange | positioned in a position lower than a water heater and the said water cooling heat exchanger.

  According to the present invention, it is possible to install an air-cooled heat exchanger in a lower place than before, thereby suppressing the increase in the height of the reactor building and reducing the construction cost of the nuclear power plant. Moreover, since the inflow of the condensed water to a water cooling heat exchanger can be suppressed, the heat transfer performance fall of a water cooling system can be suppressed.

  Problems, configurations, and effects other than those described above will be clarified by the following description of embodiments.

It is the schematic showing the structure of the reactor cooling equipment which concerns on 1st Embodiment of this invention. It is the schematic showing the structure of the reactor cooling equipment which concerns on 2nd Embodiment of this invention. It is the schematic showing the structure of the reactor cooling equipment which concerns on 3rd Embodiment of this invention. It is the schematic showing the structure of the reactor cooling equipment which concerns on 4th Embodiment of this invention. It is the schematic showing the heat exchanger tube structure of the air-cooling heat exchanger which concerns on 4th Embodiment of this invention. It is the schematic showing the structure of the reactor cooling equipment which concerns on 5th Embodiment of this invention. It is the schematic showing the structure of the reactor cooling equipment which concerns on 6th Embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals, and detailed description of the overlapping portions is omitted.

[Constitution]
With reference to FIG. 1, the structure of the reactor cooling equipment which concerns on 1st Embodiment of this invention is demonstrated. FIG. 1 is a schematic diagram illustrating a configuration of a reactor cooling facility according to the present embodiment. As shown in FIG. 1, a water cooling pool 10 of a water cooling system is installed above the containment vessel 3, and a water cooling heat exchanger 11 is installed in the water cooling pool 10.

  The condensation tank 20 containing the intermediate heat exchanger 21 is installed at a position lower than the water cooling pool 10, and a separated steam discharge pipe 31 extending from above the condensation tank 20 is connected to the water cooling heat exchanger inlet header 12. The intermediate condensed water discharge pipe 43 extending from the bottom of the condensation tank 20 is connected to the suppression pool 5. A steam trap 27 is installed in the middle of the intermediate condensed water discharge pipe 43.

  Further, the internal space of the condensing tank 20 and the containment vessel 3 is connected by a steam introduction pipe 30 extending from near the center of the condensing tank 20. The water-cooled heat exchanger outlet header 13 and the suppression pool 5 are connected by a water-cooled condensed water discharge pipe 32.

  The intermediate heat exchanger 21 in the condensation tank 20 is connected to an air-cooled heat exchanger 24 installed in a flow path formed between the reactor building 4 and the building cover 6. Water, which is a refrigerant, is sealed inside an air-cooled condensed water pipe 42 that connects the intermediate heat exchanger inlet header 22 and the air-cooled heat exchanger outlet header 26.

[Operation]
The operation of the reactor cooling facility in this embodiment will be described.

  When an accident occurs, the core 1 is scrammed and the chain reaction in the reactor stops. However, since decay heat continues to be generated, the water inside the pressure vessel 2 is heated and steam is continuously generated. The generated steam may move to the storage container 3 through a safety valve or a broken pipe, for example, and the pressure of the storage container 3 may increase. In this case, in order to prevent overpressure damage of the storage container 3, it is necessary to cool and condense the generated steam to suppress the pressure increase of the storage container 3.

  When an accident occurs, the water cooling system and the air cooling system are activated, and the steam in the containment vessel 3 is taken into the condensation tank 20 through the steam introduction pipe 30. A part of the steam flowing into the condensation tank 20 is cooled by the intermediate heat exchanger 21 and condensed. The water condensed in the intermediate heat exchanger 21 falls to the bottom of the condensation tank 20 due to gravity. The steam remaining without being condensed flows into the water-cooled heat exchanger inlet header 12 through the separated steam discharge pipe 31 connected to the upper part of the condensation tank 20.

  Thus, the steam from which the condensed water is separated in the condensation tank 20 flows into the water-cooled heat exchanger 11. The inside of the heat transfer tube of the water-cooled heat exchanger 11 is condensing heat transfer, and the condensed water becomes a heat transfer resistance, so that if the steam flowing into the water-cooled heat exchanger 11 contains condensed water, the heat transfer performance is reduced. With the structure of this embodiment, it is possible to suppress the condensed water generated in the intermediate heat exchanger 21 from flowing into the water-cooled heat exchanger 11, and to suppress the performance degradation of the water-cooled heat exchanger 11.

  The steam flowing into the water-cooled heat exchanger 11 is cooled by the cooling water in the water-cooled pool 10 and condensed. The condensed water is returned to the suppression pool 5 by gravity through the water-cooled condensed water discharge pipe 32 connected to the water-cooled heat exchanger outlet header 13. A head pressure corresponding to the height of the pipe 32 is generated, and the steam in the containment vessel 3 newly flows into the condensing tank 20 through the steam introduction pipe 30 using the driving force as a force for the condensed water to drop by the head pressure. . The condensed water that has dropped to the bottom of the condensation tank 20 is returned to the suppression pool 5 by gravity through the intermediate condensed water discharge pipe 43.

  When the pressure in the suppression pool 5 is lower than the pressure in the condensation tank 20, steam may flow into the suppression pool 5 together with the condensed water. When steam having a large enthalpy returns to the suppression pool 5 in the containment vessel 3, heat is returned to the containment vessel 3, and the heat removal efficiency by the cooling facility may be reduced. In the present embodiment, the steam trap 27 is installed in the middle of the pipe 43 in order to suppress a decrease in heat removal efficiency. The steam trap 27 has a structure in which when condensed water is accumulated, the valve is opened to release condensed water, and when the condensed water is exhausted, the valve is closed and steam is not discharged. Steam outflow from the condensation tank 20 to the suppression pool 5 can be suppressed by the steam trap 27.

  When the steam flowing in from the containment vessel 3 is condensed by the intermediate heat exchanger 21, the water inside the heat transfer tube of the intermediate heat exchanger 21 boils due to the latent heat of the steam. The steam inside the heat transfer tube generated by boiling flows from the intermediate heat exchanger outlet header 23 through the air cooling steam pipe 41 to the air cooling heat exchanger inlet header 25. The air-cooling heat exchanger 24 is installed in an air flow path formed between the reactor building 4 and the building cover 6, and cools the steam inside the heat transfer tubes with the air in the flow path.

  The cooled steam condenses and returns to water, and moves by gravity from the air-cooled heat exchanger outlet header 26 to the intermediate heat exchanger inlet header 22 through the air-cooled condensed water piping 42 and is again heated to the steam in the condensation tank 20. Has been boiling. The air around the air-cooled heat exchanger 24 exchanges heat with the steam in the heat transfer tubes, and the temperature rises. Since the air whose temperature has risen has a low density, the air rises in the flow path due to buoyancy and is discharged from the air outlet 34 to the atmosphere. When the heated air flows upward, ambient low-temperature air is newly taken into the flow path from the air inlet 33 to cool the heat transfer tubes.

  Thus, although it can cool continuously with air, without using a dynamic apparatus, since air is used for returning condensed water to the intermediate heat exchanger 21, the air-cooled heat exchanger 24 is more than the intermediate heat exchanger 21. It is necessary to install at a higher position. The air cooling heat exchanger 24 is installed in the air flow path between the reactor building 4 and the building cover 6, and the air outlet 34 is positioned higher than the air cooling heat exchanger 24 in order to obtain a chimney effect. As the air outlet 34 is located higher than the air-cooling heat exchanger 24, the air flow rate in the flow path increases due to the chimney effect, and the heat transfer efficiency of the air-cooling heat exchanger 24 is improved.

  Further, water may be sprayed from the outside to the air cooling heat exchanger 24. Since the air-cooling heat exchanger 24 can be installed in a low place, it is easy to spray water on the air-cooling heat exchanger 24. Because water improves heat transfer efficiency over air, more heat can be removed through the air cooling system.

[effect]
In this embodiment, since the condensation tank 20 is installed in a low place, the air-cooled heat exchanger 24 can also be installed in the low place. By installing the air cooling heat exchanger 24 in a low place, it is possible to suppress an increase in the height of the reactor building 4 and to suppress an increase in the construction cost of the nuclear power plant due to the installation of the air cooling system. Moreover, if the height of the air discharge port 34 is the same, the flow path height above the air cooling heat exchanger 24 can be increased, and the air flow rate is increased by increasing the chimney effect so that air cooling heat exchange is achieved. The heat transfer efficiency of the vessel 24 is improved.

  In addition, the structure in which the condensed water generated in the intermediate heat exchanger 21 is separated in the condensation tank 20 and only the steam is allowed to flow into the water-cooled heat exchanger 11 can suppress a decrease in heat transfer performance of the water-cooled heat exchanger 11. it can.

  Further, by installing a steam trap 27 in the intermediate condensed water discharge pipe 43 for returning the condensed water in the condensation tank 20 to the suppression pool 5, it is possible to suppress the return of steam to the containment vessel 3, and the heat removal efficiency by the reactor cooling facility Can be improved. Since the air cooling system is used in combination, the capacity of the water cooling pool 10 can be made smaller than the cooling equipment of the water cooling system alone, or the period during which the water cooling can be performed can be extended.

[Constitution]
With reference to FIG. 2, the structure of the reactor cooling equipment which concerns on 2nd Embodiment of this invention is demonstrated. FIG. 2 is a schematic diagram showing the configuration of the reactor cooling facility according to the present embodiment. The difference from the first embodiment is that the condensing tank 20 is connected to the pressure vessel 2 by a steam introduction pipe 30, an intermediate condensed water discharge pipe 43 for returning condensed water generated in the intermediate heat exchanger 21, and water-cooled heat exchange. The water-cooled condensed water discharge pipe 32 extending from the vessel outlet header 13 is connected to the pressure vessel 2, and the condensation tank 20 is installed at a height between the water-cooled pool 10 and the pressure vessel 2. It is.

[Operation]
In this embodiment, steam is supplied from the pressure vessel 2 to the condensation tank 20 through the steam introduction pipe 30 and the condensed water condensed in the intermediate heat exchanger 21 and the water-cooled heat exchanger 11 is returned to the pressure vessel 2. The operation is the same as that of the embodiment. Since the condensation tank 20 is installed at a position higher than the normal water level of the pressure vessel 2, the condensed water that has dropped to the bottom of the condensation tank 20 is returned to the pressure vessel 2 by gravity. Further, since the water-cooled heat exchanger 11 is also installed at a position higher than the pressure vessel 2, the condensed water is returned to the pressure vessel 2 by gravity.

[effect]
In addition to the effects of the first embodiment, there are the following effects. When the pressure vessel 2 is healthy, the pressure is higher than that of the containment vessel 3 due to the steam generated by the decay heat of the core 1. In the present embodiment, the pressure inside the condensing tank 20 and the water-cooled heat exchanger 11 is increased, and the temperature difference with the cooling water and air of the water-cooled pool 10 that is the final heat radiation source is increased. Will improve. Further, since the condensed water is directly returned to the pressure vessel 2, the amount of water in the pressure vessel 2 can be maintained without water injection from the outside, and the cooling of the fuel rod with water is continued to maintain the soundness of the core 1. be able to.

[Constitution]
With reference to FIG. 3, the structure of the reactor cooling equipment which concerns on 3rd Embodiment of this invention is demonstrated. FIG. 3 is a schematic diagram showing the configuration of the reactor cooling facility according to the present embodiment. The difference from the second embodiment is that the condensation tank 20 is installed at a position lower than the normal water level of the pressure vessel 2, and the bottom of the condensation tank 20 is connected to the suppression pool 5 by an intermediate condensed water discharge pipe 43. The steam trap 27 is installed in the middle of the condensed water discharge pipe 43.

  The steam turbine 50 further includes a steam turbine 50 and a pump 51 driven by the steam turbine. The steam turbine 50 is installed in the middle of a steam turbine steam extraction pipe 52 connected to the suppression pool 5 from the pressure vessel 2, and the pump 51 is connected to the suppression pool. 5 is installed in the middle of a water injection pipe 53 connected to the pressure vessel 2. In addition, in FIG. 3, although the suppression pool 5 is shown separated into right and left as sectional drawing, it is the integral structure connected in the circumferential direction in fact.

[Operation]
This embodiment is the same as the second embodiment except that the condensed water in the condensation tank 20 is returned to the pressure vessel 2 through the suppression pool 5, and therefore the operation for returning the condensed water to the pressure vessel 2 will be described. The condensed water condensed in the intermediate heat exchanger 21 falls to the bottom of the condensation tank 20 and is discharged to the suppression pool 5 through the intermediate condensed water discharge pipe 43 connected to the suppression pool 5. Since the pressure difference between the condensation tank 20 connected to the pressure vessel 2 and the suppression pool 5 is large, a steam trap 27 is installed in the middle of the intermediate condensed water discharge pipe 43, and the steam flowing into the condensation tank 20 excessively suppresses the suppression pool 5. To prevent it from leaking.

  Since the suppression pool 5 is located at a position lower than the pressure vessel 2, water cannot be returned to the pressure vessel 2 by gravity. Therefore, the water in the suppression pool 5 is returned to the pressure vessel 2 by using a pump 51 driven by the steam turbine 50 installed in the middle of the steam extraction pipe 52 for steam turbine connected from the pressure vessel 2 to the suppression pool 5. Yes. Since the steam turbine 50 is driven by steam flowing at a differential pressure between the pressure vessel 2 and the suppression pool 5, it is a static device that does not require an external power source. The steam that has driven the steam turbine 50 flows into the suppression pool 5, condenses, and is returned to the pressure vessel 2 by the pump 51.

[effect]
In addition to the effects of the second embodiment, there are the following effects. In this embodiment, since the condensation tank 20 can be installed in a lower place, the air-cooled heat exchanger 24 can also be installed in a lower place, suppressing the increase in the height of the reactor building 4 and increasing the construction cost of the nuclear power plant. Can be suppressed.

[Constitution]
With reference to FIG. 4, the structure of the reactor cooling equipment which concerns on 4th Embodiment of this invention is demonstrated. FIG. 4 is a schematic diagram showing the configuration of the reactor cooling facility according to the present embodiment. FIG. 5 is an enlarged schematic view showing the heat transfer tube configuration of the air-cooling heat exchanger 24 in FIG. A difference from the first embodiment is that a refrigerant tank 28 that stores water as a refrigerant is installed in the middle of an air-cooled condensed water pipe 42 that returns condensed water from the air-cooled heat exchanger outlet header 26 to the intermediate heat exchanger inlet header 22. It is that. The water level of the refrigerant tank 28 is adjusted so as to be located between the center and the upper end of the heat transfer tube of the intermediate heat exchanger 21.

  Further, as shown in FIG. 5, a part of the heat transfer tubes 29b of the air-cooling heat exchanger 24 is connected only to the air-cooling heat exchanger outlet header 26, and an open / close valve 61 is installed at the other end thereof. When the open / close valve 61 is opened, the inside of the heat transfer tube 29b communicates with the atmosphere. The heat transfer tube 29b may be connected only to the air-cooled heat exchanger outlet header 25.

[Operation]
In this embodiment, the operation is the same as in the first embodiment, but the heat removal performance of the air cooling system is stabilized by installing the refrigerant tank 28. This operation will be described. When the intermediate heat exchanger 21 in the condensation tank 20 receives heat from the steam, water that is a refrigerant in the heat transfer tube of the intermediate heat exchanger 21 boils. The boiled water becomes steam and moves to the air cooling heat exchanger 24 through the air cooling steam pipe 41. The air is cooled by air inside the heat transfer tube of the air-cooling heat exchanger 24 to condense the steam, and the condensed water falls by gravity, and flows into the refrigerant tank 28 from the air-cooling heat exchanger outlet header 26 through the air-cooling condensed water piping 42. To do.

  Inside the heat transfer tube of the intermediate heat exchanger 21, heat transfer is performed by boiling water, but when the water level inside the heat transfer tube is low, the upper part of the heat transfer tube is filled with only steam, and the heat transfer mode is boiling heat transfer. It becomes convective heat transfer of steam from single phase. Generally, since the convective heat transfer coefficient is lower than the boiling heat transfer coefficient, the heat transfer efficiency is improved when the water level inside the heat transfer tube is higher.

  Therefore, also in the first embodiment, an amount of water that can sufficiently maintain the water level inside the heat transfer tube is stored in the air-cooled condensed water piping 42. However, if the volume of the air-cooled condensed water pipe 42 is small, for example, if the refrigerant temporarily stays in the loop of the air-cooling system, the return water to the heat transfer pipe of the intermediate heat exchanger 21 decreases and the water level inside the heat transfer pipe is reduced. The operation may become unstable, such as a decrease in the amount of heat removal and a temporary decrease in heat removal.

  Therefore, in this embodiment, the refrigerant tank 28 is installed, and the water level of the refrigerant tank 28 is adjusted so as to be located at the upper end position from the center of the heat transfer tube of the intermediate heat exchanger 21. The static water level of the heat transfer tube is the same as the water level of the refrigerant tank 28. Even if the refrigerant temporarily accumulates in the loop of the air cooling system, sufficient water is stored in the refrigerant tank 28, so that the water level in the heat transfer tube of the intermediate heat exchanger 21 does not fluctuate greatly. .

  Moreover, in this embodiment, as shown in FIG. 5, the opening / closing valve 61 is installed in the one part heat exchanger tube 29b of the air-cooling heat exchanger 24. As shown in FIG. In the normal operation of the air cooling system, the water as the refrigerant circulates in the loop to remove heat while the on-off valve 61 is closed. On the other hand, when the opening / closing valve 61 is opened, the vapor in the air cooling system is released to the atmosphere. Since the steam generated in the intermediate heat exchanger 21 is directly released to the atmosphere and is not affected by the convective heat transfer of air having a high thermal resistance, it is possible to remove more heat from the reactor with an air cooling system. it can.

  In the unlikely event that the heat removal amount of the water cooling system decreases, the opening / closing valve 61 is opened to compensate for the decrease in the heat removal amount of the water cooling system, thereby suppressing the overpressure of the reactor. As long as water can be supplied from the refrigerant tank 28 to the heat transfer pipe of the intermediate heat exchanger 21, heat removal with a large heat removal amount by opening the on-off valve 61 can be performed. Therefore, by installing the refrigerant tank 28, the air cooling system can be used for a longer period of time. A water cooling system can be substituted.

[effect]
In addition to the effects of the first embodiment, there are the following effects. In this embodiment, by installing the refrigerant tank 28, the water level in the heat transfer tube of the intermediate heat exchanger 21 can be kept constant, and the heat removal performance of the air cooling system can be stabilized. In the unlikely event that the heat removal amount of the water cooling system is reduced, the opening / closing valve 61 is opened to compensate for the decrease in the heat removal amount of the water cooling system using the air cooling system.

  The refrigerant tank 28 and the opening / closing valve 61 may be applied to the cooling equipment of the second embodiment and the third embodiment, and the same effect is obtained.

[Constitution]
With reference to FIG. 6, the structure of the reactor cooling equipment which concerns on 5th Embodiment of this invention is demonstrated. FIG. 6 is a schematic diagram showing the configuration of the reactor cooling facility according to the present embodiment. As shown in FIG. 6, a water cooling pool 10 of a water cooling system is installed above the containment vessel 3, and a water cooling heat exchanger 11 is installed in the water cooling pool 10. A cooling water tank 60 storing cooling water therein is installed at a position lower than the water cooling pool 10, and an intermediate heat exchanger 21 is installed inside the cooling water tank 60. The intermediate heat exchanger inlet header 22 and the containment vessel 3 are connected by a steam introduction pipe 30.

  An intermediate condensed water discharge pipe 43 connected to the intermediate heat exchanger outlet header 23 and extending from the bottom of the cooling water tank 60 is connected to the suppression pool 5, and a separated steam discharge pipe 31 extending upward from the intermediate heat exchanger outlet header 23. Is connected to a water-cooled heat exchanger inlet header 12. A steam trap 27 is installed in the intermediate condensed water discharge pipe 43 connected to the suppression pool 5. An air-cooled steam pipe 41 extending from the upper part of the cooling water tank 60 is connected to the air-cooling heat exchanger inlet header 25, and an air-cooled condensed water pipe 42 extending from the air-cooling heat exchanger outlet header 26 is located near the center of the side surface of the cooling water tank 60. It is connected. The water level of the cooling water tank 60 is set so that the intermediate heat exchanger 21 is sufficiently submerged.

[Operation]
The operation of the reactor cooling facility in this embodiment will be described. When an accident occurs, the water cooling system and the air cooling system are activated, and the steam in the containment vessel 3 is taken into the heat transfer pipe of the intermediate heat exchanger 21 through the steam introduction pipe 30. The intermediate heat exchanger 21 is submerged in the water of the cooling water tank 60, and the steam taken into the intermediate heat exchanger 21 is deprived of heat by the water of the cooling water tank 60 and part of it is condensed. The mixed fluid of steam and condensed water that has reached the intermediate heat exchanger outlet header 23 is separated into steam and condensed water by utilizing the fact that condensed water accumulates at the bottom in the space of the intermediate heat exchanger outlet header 23 due to gravity. Is done.

  The separated steam flows into the water-cooled heat exchanger 11 through the separated steam discharge pipe 31 and condenses inside the heat transfer tube of the water-cooled heat exchanger 11. The condensed water flows out to the suppression pool 5 through the water-cooled condensed water discharge pipe 32. The condensed water separated by the intermediate heat exchanger outlet header 23 flows out to the suppression pool 5 through the intermediate condensed water discharge pipe 43. The steam trap 27 installed in the middle of the intermediate condensed water discharge pipe 43 prevents the steam from flowing out to the suppression pool 5 through the intermediate condensed water discharge pipe 43.

  When steam flows into the heat transfer tube of the intermediate heat exchanger 21, heat is transferred to the water in the cooling tank 60 through the heat transfer tube. Since the steam temperature is higher than the saturation temperature of the pressure in the air cooling system, the temperature of the water in the cooling water tank 60 rises and eventually boils. The steam generated in the cooling water tank 60 is taken into the air cooling heat exchanger 24 through the air cooling steam pipe 41. The steam taken into the air-cooling heat exchanger 24 is cooled by air and condensed. The condensed water is returned to the cooling water tank 60 through the air-cooled condensed water piping 42.

  As long as the intermediate heat exchanger 21 is not exposed from the water surface of the cooling water tank 60, boiling heat transfer can be used and the performance does not deteriorate. Even if the refrigerant temporarily accumulates in the loop of the air cooling system, the intermediate heat exchanger 21 is not exposed from the water surface because the refrigerant is sufficiently stored in the cooling water tank 60, and the intermediate heat exchanger is not exposed. 21 performances can be maintained.

  In the present embodiment, the water-cooled heat exchanger 11 and the intermediate heat exchanger 21 perform heat transfer according to the same principle, but the heat removal amount in the intermediate heat exchanger 21 is the heat removal amount of the air-cooled heat exchanger 24 having a large thermal resistance. Affected by. The water-cooled pool 10 is open to the atmosphere, and when the pool water reaches the atmospheric pressure saturation temperature (about 100 ° C), the pool water temperature does not exceed the atmospheric pressure saturation temperature. Heat transfer is performed by the difference.

  On the other hand, since the air cooling system is a closed loop, when the amount of steam generated in the cooling water tank 60 is larger than the amount of condensation in the air cooling heat exchanger 24, the pressure of the cooling water tank 60 increases. When the pressure rises, the saturation temperature also rises, and the water temperature in the cooling water tank 60 rises to the saturation temperature, so that the temperature difference from the steam temperature becomes small and the heat removal amount in the intermediate heat exchanger 21 decreases. In the air-cooled heat exchanger 24, the saturated steam temperature inside the heat transfer tube rises, so the temperature difference from the air increases and the amount of heat removal increases. The pressure in the loop of the air cooling system increases until the amount of steam generated in the cooling water tank 60 and the amount of condensation in the air cooling heat exchanger 24 are balanced.

  In the present embodiment, the steam that has flowed into the intermediate heat exchanger 21 is cooled by the cooling water outside the heat transfer tube, similarly to the water-cooled heat exchanger 11, but from the water-cooled heat exchanger 11 due to the rise in the water temperature of the cooling water tank 60. However, the heat transfer efficiency decreases. When steam exceeding the heat removal capacity of the air-cooled heat exchanger 24 flows in, the condensation of the steam is not completed in the intermediate heat exchanger 21, and the two-phase flow of steam and condensed water is generated in the intermediate heat exchanger outlet header 23. leak. The steam separated at the intermediate heat exchanger outlet header 23 flows into the water-cooled heat exchanger 11, and all the steam is condensed.

  Also in the present embodiment, after securing a sufficient capacity of the cooling water tank 60, an opening / closing valve 61 is installed at one end of a part of the heat transfer pipe 29b of the air-cooling heat exchanger 24 as in the fourth embodiment. When the opening / closing valve 61 is opened, the inside of the heat transfer tube and the atmosphere may be communicated. When a large amount of heat removal is required temporarily, by opening the valve 61, a large amount of heat can be released to the atmosphere without receiving a large air-cooling thermal resistance.

  In addition, you may replace the air cooling system comprised by the cooling water tank 60 of this embodiment with the air cooling system comprised by the condensation tank 20 of 1st Embodiment-4th Embodiment.

[effect]
In this embodiment, since the intermediate heat exchanger 21 is submerged in the cooling water tank 60, boiling heat transfer can be used even if the water level in the cooling water tank 60 slightly changes, and heat removal of the air cooling system is possible. The performance can be stabilized. In the unlikely event that the heat removal amount of the water cooling system is reduced, the opening / closing valve 61 is opened to compensate for the decrease in the heat removal amount of the water cooling system using the air cooling system.

[Constitution]
With reference to FIG. 7, the structure of the reactor cooling equipment which concerns on 6th Embodiment of this invention is demonstrated. FIG. 7 is a schematic diagram showing the configuration of the reactor cooling facility according to the present embodiment. This embodiment is different from the first embodiment in that the condensation tank 20 is installed inside the storage container 3. Other configurations are the same as those in the first embodiment. With this configuration, the pipes penetrating the containment vessel 3 are separated steam discharge pipes 31 that connect the condensation tank 20 and the water-cooled heat exchanger 11, and air-cooled steam pipes 41 that connect the intermediate heat exchanger 21 and the air-cooled heat exchanger 24. And air-cooled condensed water piping 42.

[Operation]
The operation is the same as in the first embodiment.

[effect]
Even if the air-cooled steam pipe 41 or the air-cooled condensed water pipe 42 connecting the intermediate heat exchanger 21 and the air-cooled heat exchanger 24 is broken by configuring the reactor cooling equipment as in the present embodiment, two Because of the secondary piping, the gas containing the radioactive substance in the containment vessel 3 does not flow out of the containment vessel 3. In the present embodiment, since the steam introduction pipe 30 and the intermediate condensed water discharge pipe 43 that are primary systems can be arranged inside the containment vessel 3, it is possible to reduce the risk of releasing radioactive materials to the environment in the unlikely event of a pipe break. it can.

  Note that the condensation tank 20 or the cooling water tank 60 of the second to fifth embodiments may be installed inside the storage container 3 as in this embodiment, and the same effect is obtained.

  The present invention is not limited to the above-described embodiments, and includes various modifications. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Further, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Further, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

DESCRIPTION OF SYMBOLS 1 ... Core 2 ... Pressure vessel 3 ... Containment vessel 4 ... Reactor building 5 ... Suppression pool 6 ... Building cover 7 ... Ground (ground)
DESCRIPTION OF SYMBOLS 10 ... Water cooling pool 11 ... Water cooling heat exchanger 12 ... Water cooling heat exchanger inlet header 13 ... Water cooling heat exchanger outlet header 20 ... Condensation tank 21 ... Intermediate heat exchanger 22 ... Intermediate heat exchanger inlet header 23 ... Intermediate heat exchanger Outlet header 24 ... Air-cooled heat exchanger 25 ... Air-cooled heat exchanger inlet header 26 ... Air-cooled heat exchanger outlet header 27 ... Steam trap 28 ... Refrigerant tank 29, 29a, 29b ... (Air-cooled) Heat transfer pipe 30 ... Steam introduction piping 31 ... Separation steam discharge pipe 32 ... Water-cooled condensed water discharge pipe 33 ... Air inlet 34 ... Air outlet 41 ... Air-cooled steam pipe 42 ... Air-cooled condensed water pipe 43 ... Intermediate condensed water discharge pipe 44 ... Refrigerant supply pipe 50 ... Steam turbine 51 ... Pump 52 ... Steam extraction pipe for steam turbine 53 ... Water injection pipe 60 ... Cooling water tank 61 ... Open / close valve

Claims (18)

A reactor containment vessel containing a pressure vessel;
A condensing tank containing an intermediate heat exchanger;
An air-cooled heat exchanger that is connected to the intermediate heat exchanger by an air-cooling loop pipe and cools and condenses the steam introduced into the condensation tank by circulating a refrigerant between the intermediate heat exchanger and
A water-cooled pool provided on the upper side of the reactor containment vessel;
Water that is installed in the water-cooled pool and introduces steam that has not been condensed in the condensation tank via a separated steam discharge pipe connected to the upper side of the condensation tank, and cools and condenses the introduced steam. A nuclear power plant having a cold heat exchanger,
The nuclear power plant, wherein the condensation tank is disposed at a position lower than the air-cooled heat exchanger and the water-cooled heat exchanger. The nuclear power plant according to claim 1,
The condensation tank is disposed at a position higher than the normal water level of the suppression pool in the reactor containment vessel,
The outlet header of the water-cooled heat exchanger is connected to the suppression pool via a water-cooled condensed water discharge pipe,
The nuclear power plant, wherein a lower side of the condensing tank is connected to the suppression pool via an intermediate condensed water discharge pipe. The nuclear power plant according to claim 1,
The condensation tank is disposed at a position higher than the normal water level in the pressure vessel,
The outlet header of the water-cooled heat exchanger is connected to the pressure vessel via a water-cooled condensed water discharge pipe,
A nuclear power plant, wherein a lower side of the condensation tank is connected to the pressure vessel via an intermediate condensed water discharge pipe. The nuclear power plant according to claim 1,
The condensation tank is disposed at a position higher than the normal water level of the suppression pool in the reactor containment vessel,
The outlet header of the water-cooled heat exchanger is connected to the pressure vessel via a water-cooled condensed water discharge pipe,
The nuclear power plant, wherein a lower side of the condensing tank is connected to the suppression pool via an intermediate condensed water discharge pipe. A nuclear power plant according to claim 4,
A steam extraction pipe connecting the pressure vessel and the suppression pool;
A water injection pipe for connecting the pressure vessel and the suppression pool and supplying cooling water from the suppression pool to the pressure vessel, and
A steam turbine is provided in the middle of the steam extraction pipe,
A nuclear power plant comprising a pump driven by the steam turbine in the middle of the water injection pipe. A nuclear power plant according to any one of claims 1 to 5,
A refrigerant tank is provided in the middle of the air-cooled loop piping,
The nuclear power plant, wherein a water level of the refrigerant tank is located between a center and an upper end of the intermediate heat exchanger. A nuclear power plant according to claim 6,
A nuclear power plant characterized in that an air-cooling heat transfer tube constituting the air-cooling heat exchanger is provided with an open / close valve that discharges steam in the air-cooling heat transfer tube to the atmosphere. A nuclear power plant according to any one of claims 1 to 7,
A nuclear power plant, wherein steam is introduced from the reactor containment vessel or the pressure vessel into the condensation tank through a steam introduction pipe. A nuclear power plant according to any one of claims 1 to 8,
The nuclear power plant, wherein the condensation tank is installed in the reactor containment vessel. A reactor containment vessel containing a pressure vessel;
A cooling water tank containing the intermediate heat exchanger;
An air-cooling heat exchanger connected to the cooling water tank by an air-cooling loop pipe and cooling and condensing steam introduced from the cooling water tank;
A water-cooled pool provided on the upper side of the reactor containment vessel;
The remaining steam that is not condensed in the intermediate heat exchanger is introduced through the separated steam discharge pipe that is installed in the water-cooled pool and connected to the outlet header of the intermediate heat exchanger, and the introduced steam is cooled and condensed. A nuclear power plant having a water-cooled heat exchanger,
The nuclear power plant, wherein the cooling water tank is disposed at a position lower than the air cooling heat exchanger and the water cooling heat exchanger. The nuclear power plant according to claim 10, wherein
The cooling water tank is disposed at a position higher than the normal water level of the suppression pool in the reactor containment vessel,
The outlet header of the water-cooled heat exchanger is connected to the suppression pool via a water-cooled condensed water discharge pipe,
The outlet header of the intermediate heat exchanger is connected to the inlet header of the water-cooled heat exchanger via a separated steam exhaust pipe, and is connected to the suppression pool via an intermediate condensed water discharge pipe. Nuclear plant. The nuclear power plant according to claim 10, wherein
The cooling water tank is disposed at a position higher than the normal water level in the pressure vessel,
The outlet header of the water-cooled heat exchanger is connected to the pressure vessel via a water-cooled condensed water discharge pipe,
The nuclear power plant, wherein an outlet header of the intermediate heat exchanger is connected to the pressure vessel through an intermediate condensed water discharge pipe. The nuclear power plant according to claim 10, wherein
The cooling water tank is disposed at a position higher than the normal water level of the suppression pool in the reactor containment vessel,
The outlet header of the water-cooled heat exchanger is connected to the pressure vessel via a water-cooled condensed water discharge pipe,
The nuclear power plant, wherein an outlet header of the intermediate heat exchanger is connected to the suppression pool via an intermediate condensed water discharge pipe. A nuclear power plant according to claim 13,
A steam extraction pipe connecting the pressure vessel and the suppression pool;
A water injection pipe for connecting the pressure vessel and the suppression pool and supplying cooling water from the suppression pool to the pressure vessel, and
A steam turbine is provided in the middle of the steam extraction pipe,
A nuclear power plant comprising a pump driven by the steam turbine in the middle of the water injection pipe. A nuclear power plant according to any one of claims 10 to 14,
A nuclear power plant characterized in that an air-cooling heat transfer tube constituting the air-cooling heat exchanger is provided with an open / close valve that discharges steam in the air-cooling heat transfer tube to the atmosphere. A nuclear power plant according to any one of claims 10 to 15,
A nuclear power plant, wherein steam is introduced into the intermediate heat exchanger from the reactor containment vessel or the pressure vessel through a steam introduction pipe. A nuclear power plant according to any one of claims 10 to 16,
The nuclear power plant, wherein the cooling water tank is installed in the reactor containment vessel. A nuclear power plant according to any one of claims 2 to 5 and 11 to 14,
A nuclear power plant characterized by providing a steam trap in the middle of the intermediate condensed water discharge pipe.

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