JP2014153305A - Nuclear power plant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nuclear power plant capable of cooling warm seawater used for continuously cooling an auxiliary machine at a low cost.SOLUTION: A nuclear power plant includes: a water intake path (102) in which seawater taken from sea (108) is stored; a pump (130) that pumps up seawater in the water intake path (102) as cooling water for an auxiliary machine (310) in a nuclear reactor building (300); and cooling facilities (15) that exchange heat with the auxiliary machine (310) to cool the heated seawater by exchanging heat with air and returns the cooled seawater to the water intake path (102).

Description

  The present invention relates to a nuclear power plant, and more particularly to a plant cooling water cooling system.

  The nuclear power plant includes an auxiliary cooling water system as a system for cooling each auxiliary machine installed in the reactor building and the turbine building. The seawater pump group that pumps seawater (cooling water) to be supplied to the auxiliary cooling water system from the water channel includes a reactor auxiliary cooling seawater pump for cooling the reactor auxiliary equipment in the reactor building. And a circulating water pump (CWP) for cooling (condensating) steam driving a steam turbine in the turbine building with a condenser, and turbine auxiliary machine cooling seawater for cooling the turbine auxiliary machine in the turbine building A pump (TSW pump) is included. When large-scale tsunamis (push waves and pulling waves) occur due to large-scale earthquakes, the plant-use circulating water pumps and turbine auxiliary cooling seawater pumps in the aforementioned seawater pump group ensure the reactor cooling function. -In order to maintain it, it is stopped by manual operation at the discretion of the operator after confirming various status information based on the tsunami countermeasure operation procedure specified in advance. On the other hand, it is planned that the operation of the reactor auxiliary cooling seawater pump necessary for reactor cooling will be continued to ensure and maintain a stable reactor cooling function.

  As a technology for securing the water source of the seawater pump when a tsunami occurs, for example, a weir is installed in the intake channel and an emergency seawater storage pool is installed above the intake channel. A structure in which the seawater (hot water) pumped from the intake channel by the reactor auxiliary cooling seawater pump and used to cool the auxiliary machinery is led to the emergency seawater storage pool, and the seawater overflowing from the pool is returned to the waterway. By doing so, there is one that can secure the cooling water from the intake channel even if the seawater level drops due to the pulling due to the earthquake (see JP 2001-116880 A).

  In addition, the warm seawater used for cooling the auxiliary equipment is hotter than the intake side, but it is diluted with the seawater stored in the emergency seawater storage pool. The rise in temperature is said to be mitigated rather than being discharged directly into the intake channel.

JP 2001-116880 A

  However, in the technology of Japanese Patent Laid-Open No. 2001-116880, it is necessary to separately provide an emergency seawater storage pool for cooling the warm seawater used for cooling the auxiliary machinery, and civil engineering work for constructing the pool Costs may be relatively high. In this technology, the warm seawater is cooled by mixing the warm seawater (hot water) with seawater (cold water) stored in the pool. When the operation is continued for a long time, the seawater temperature in the pool rises and the cooling performance of the hot seawater may be reduced.

  An object of the present invention is to provide a nuclear power plant capable of continuously cooling hot seawater used for cooling an auxiliary machine at a low cost.

  In order to achieve the above object, the present invention provides a water intake channel for storing seawater taken from the sea, a pump for pumping seawater in the water intake channel as cooling water for auxiliary equipment in a reactor building, and the auxiliary device. The seawater heated and exchanged with the machine is cooled by exchanging heat with air and cooled, and the cooled seawater is returned to the intake channel.

  According to the present invention, the cooling of the warm seawater used for cooling the auxiliary equipment can be continued at a low cost.

1 is a schematic diagram of a nuclear power plant according to an embodiment of the present invention. The schematic block diagram of the nuclear power plant cooling water cooling system which concerns on the 1st Embodiment of this invention. The schematic block diagram of the nuclear power plant cooling water cooling system which concerns on the 2nd Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, when there are a plurality of identical components, an upper case letter may be added to the end of the symbol, but the upper case letters are omitted and the plurality of components are indicated together. There is. For example, when there are three identical pumps 190A, 190B, 190C, these may be collectively referred to as pump 190.

  FIG. 1 is a schematic diagram of a nuclear power plant according to an embodiment of the present invention. The nuclear power plant shown in this figure includes a circulating water pump (CWP) 120, a turbine building sea water system (TSW) pump 122, and a reactor auxiliary cooling water pump 130. ing.

  The CWP 120 pumps up seawater drawn from the ocean 108 via the intake channel 102, and condenses the steam that rotationally drives the turbine to a steam turbine condenser (not shown) in the turbine building 200. It is a pump which supplies as cooling water for.

  The intake of the intake channel 102 is provided on the seaside and opens to the ocean 108. A screen 106 for removing dust is installed at the inlet of the water intake. A weir 100 is provided in the vicinity of the water intake of the intake channel 102, and seawater taken from the sea 108 is stored in the intake channel 102 on the side of the buildings 200 and 300 from the weir 100. The height of the weir 100 is set to be at least lower than the normal tide level and higher than the tide level at the time of the pulling wave, and seawater remains in the intake channel 102 even when the pulling wave occurs. The intake channel 102 branches off to the auxiliary component cooling intake channel 104 at a location on the plant side (turbine building 200 and reactor building 300) from the weir 100, and seawater is also introduced into the auxiliary component cooling intake channel 104. ing.

  The TSW pumps 122A, 122B, and 122C pump up seawater from the intake channel 102, and use the seawater as cooling water for indirectly cooling the auxiliary devices 210 in the turbine building 200. This is a pump for supplying to the vessel 212. In the plant shown in FIG. 1, three TSW pumps 122A, 122B, and 122C are installed, but the number of pumps is not limited to this. Seawater pumped by the TSW pumps 122A, 122B, and C and introduced into the turbine auxiliary machine cooling water system heat exchanger 212 exchanges heat with a heated heat medium (for example, water) by cooling each auxiliary machine 210. After being heated, it is discharged into the water discharge channel 110 and returned to the ocean 108.

  The reactor auxiliary equipment cooling seawater pump 130 pumps up seawater from the intake passage 102 or the auxiliary equipment intake water passage 104 and cools the seawater indirectly to each auxiliary equipment 310 in the reactor building 300. This is a pump that supplies water to the reactor auxiliary coolant water heat exchanger 312 as water. In the plant shown in FIG. 1, three reactor auxiliary cooling seawater pumps 130A, 130B, and 130C are installed, and each system includes two pumps. The number of each system and the seawater pumps in each system The number of is not limited to this. Seawater pumped up to the reactor auxiliary machine cooling seawater pumps 130A, B, C and introduced into the reactor auxiliary machine cooling water system heat exchanger 312 is a heat medium (for example, water) ) And is heated by exchanging with the water, and then discharged to the water discharge channel 110 through the water discharge pipe 11 and returned to the ocean 108.

  In the example of FIG. 1, the intake 102 and the auxiliary cooling intake 104 are used as seawater sources, but the CWP 120, the TSW pump 122, and the reactor auxiliary cooling seawater pump 130 are disconnected from the ocean due to the tsunami. As long as the water source to be used is shared, it is not limited to the example of FIG. That is, for example, the water sources of all the pumps 120, 122, 130 may be taken as the water channel 102.

  FIG. 2 is a schematic configuration diagram of the cooling water cooling system according to the first embodiment of the present invention. In addition, the same code | symbol may be attached | subjected to the same part as the previous figure, and description may be abbreviate | omitted (it is the same also in later figures).

  The cooling water cooling system shown in this figure includes a water level gauge 8, a water discharge pipe 11, a communication pipe 6, a cooling facility 15, a water supply pipe 7, a water discharge side switching valve 9, a water intake side switching valve 10, and a control. A device 20 is provided.

  The water level gauge (water level sensor) 8 is for detecting the level of seawater in the intake channel 102, and outputs the detected water level to the control device 20. The water level gauge 8 is stored in a space (cooling water storage pool) defined by the wall surface of the intake channel 102 and the weir 100 (cooling water storage pool), and is supplied by a reactor auxiliary cooling seawater pump (hereinafter sometimes simply referred to as “pump”) 130. The water level of seawater pumped up as cooling water for the auxiliary machine 310 is detected.

  The water discharge pipe 11 is a pipe for introducing seawater heated by heat exchange with the auxiliary machine 310 in the reactor building 300 into the water discharge path 110, and connects the outlet of the heat exchanger 312 and the water discharge path 110. Yes. The water discharge pipe 11 is connected to a communication pipe 6, and a water discharge side switching valve (open / close valve) that is opened and closed based on a command from the control device 20 on the downstream side of the connection portion of the water discharge pipe 11 with the connection pipe 6. ) 9 is attached.

  The connecting pipe 6 is a pipe that connects the discharge pipe 11 and the cooling facility 15, and introduces seawater heated by heat exchange with the auxiliary machine 310 in the reactor building 300 from the discharge pipe 11 to the cooling facility 15. This is the piping. A water intake side switching valve (open / close valve) 10 that is opened and closed based on a command from the control device 20 is attached to the communication pipe 6.

  The water discharge side switching valve 9 and the water intake side switching valve 10 are connected to the discharge destination of the seawater heated by heat exchange with the auxiliary equipment 310 in the reactor building 300 and the cooling facility 15 (the communication pipe 6 or the water intake path). 102). A switching device for selectively switching to any one of 102). When the introduction destination of the seawater is the discharge channel 110, the control device 20 opens the discharge side switching valve 9 and closes the intake side switching valve 10. On the other hand, when the introduction destination of the seawater is the cooling facility 15, the control device 20 closes the water discharge side switching valve 9 and opens the water intake side switching valve 10.

  The cooling facility 15 cools the seawater introduced via the communication pipe 6 by exchanging heat with air and returns the seawater after cooling to the water channel 102. In the example shown in FIG. 2, a cooling tower (cooling tower) is used as the cooling facility 15. In the cooling tower, seawater and air (outside air) are brought into direct contact or indirect contact with each other to evaporate part of the seawater, thereby cooling the remaining seawater. The cooling tower may be equipped with a pump for pumping up the seawater to be cooled at the top of the tower and a motor for rotationally driving a fan for taking air (outside air) into the tower. In some cases, the power supply for the pump or the motor may be an emergency power supply that can be used even when an earthquake or tsunami occurs.

  The seawater cooled by the cooling facility 15 is returned to the intake channel 102 via the water supply piping (intake channel connection piping) 7. The water supply pipe 7 is a pipe for introducing seawater cooled by the cooling facility 15 into the water channel 102, and connects the cooling facility 15 and the water channel 102. A watering nozzle is provided at the end of the water supply pipe 7 shown in FIG. 2 on the intake channel 102 side, and the seawater is further cooled by spraying seawater from the watering nozzle toward the intake channel 102.

  The introduction of seawater from the cooling facility 15 to the intake channel 102 through the water supply pipe 7 and the watering by the water nozzle provided at the end of the water supply pipe 7 respectively use the pressure feed by a pump or the like that requires a drive source. It is preferable to use gravity instead. Therefore, the water supply pipe 7 is laid with a predetermined downward slope at a position higher than the ceiling surface of the intake passage 102 (for example, the upper surface of the concrete slab), and the end of the water supply pipe 7 on the intake passage 102 side and the water spray nozzle are In the intake channel 102, it is preferably installed at a position higher than the upper end of the weir 100 (for example, near the ceiling surface in the intake channel 102).

  The control device 20 outputs a signal to the water discharge side switching valve 9 and the water intake side switching valve 10 when the water level detected by the water level gauge 8 reaches less than a set value (set water level), and the auxiliary device 310 in the reactor building 300 is output. It has a function of executing processing for switching the introduction destination of the seawater heated by the water discharge channel 110 to the communication pipe 6. The detected water level is input from the water level gauge 8 to the control device 20. Although various values can be set as the set water level, it is assumed here that the height of the upper end portion of the weir 100 is set as the set water level.

  During normal operation, the water discharge side switching valve 9 is open and the water intake side switching valve 10 is closed. As a result, the seawater pumped up from the intake channel 102 by the pump 130 and heated by the heat exchanger 312 in the reactor building 300 is released to the ocean 108 through the discharge pipe 11 and the discharge channel 110.

  On the other hand, when it is confirmed that the sea level is lowered due to the tsunami caused by the earthquake and the water level detected by the water level gauge 8 has reached the set water level, the control device 20 performs the discharge side switching valve 9 and the intake side switching valve 10. Is output, the water discharge side switching valve 9 is closed, and the water intake side switching valve 10 is opened. As a result, the seawater heated by the heat exchanger 312 is introduced into the cooling facility 15 via the connection pipe 6. The seawater introduced into the cooling facility 15 is cooled by exchanging heat with air in the cooling facility 15, and is discharged to the intake channel 102 through the water supply pipe 7. Thereby, even in a situation where the seawater supply from the ocean 108 to the intake channel 102 is interrupted, an increase in the seawater temperature in the intake channel 102 can be reduced without reducing the amount of seawater in the intake channel 102. The auxiliary machine 310 in the furnace building 300 can be continuously cooled. Further, according to the present embodiment, there is no need to separately provide an emergency seawater storage pool as in the technique described in JP-A-2001-116880. Can be done.

  FIG. 3 is a schematic configuration diagram of a nuclear power plant cooling water cooling system according to the second embodiment of the present invention. The cooling water cooling system shown in this figure includes a first water discharge pipe 11, a second water discharge pipe 18, a first water discharge side switching valve 9, a first water intake side switching valve 10, and a second water discharge side switching valve 17. The second intake side switching valve 16 and thermometers (temperature sensors) 19 and 21 are provided.

  The first water discharge pipe 11 is connected to a heat exchanger 312 related to the nuclear building 300, a heat exchanger 212 related to the turbine building 200, and a condenser (not shown). In addition to seawater heated to 310, seawater heated to steam in the auxiliary machine 210 and the condenser of the turbine building 200 is introduced.

  The second water discharge pipe (other water discharge pipe) 18 is a pipe for introducing the seawater cooled by the cooling facility 15 into the water discharge path 110, and connects the water supply pipe 7 and the first water discharge pipe 11. The connection location with the 2nd water discharge piping 18 in the 1st water discharge piping 11 is located in the downstream rather than the connection location with the connection piping 6. FIG.

  The first water discharge pipe 11 is provided with a thermometer 19 at a position downstream of the connection point with the second water discharge pipe 18. The thermometer 19 is for detecting the temperature of seawater when passing through the water discharge channel 110, and outputs the detected temperature to the control device 20. A thermometer 21 is installed in the intake channel 102. The thermometer 21 is for detecting the temperature of seawater in the intake channel 102 or the ocean 108, and outputs the detected temperature to the control device 20. The thermometer 21 does not need to be installed in the intake channel 102 and may be installed in the vicinity of the intake channel 102.

  The temperature detected by the two thermometers 19 and 21 is such that the difference between the seawater temperature during intake (temperature in the intake channel 102) and the seawater temperature during drainage (temperature when drained from the drainage channel 110) is within a predetermined range (set temperature). ), The control device 20 determines whether or not the temperature deviation between the two exceeds a predetermined set value, and based on the determination, the first water discharge side switching valve 9, The first intake side switching valve 10, the second discharge side switching valve 17, and the second intake side switching valve 16 are controlled.

  The first water discharge side switching valve 9, the first water intake side switching valve 10, the second water discharge side switching valve 17, and the second water intake side switching valve 16 are open / close valves that are opened and closed based on commands from the control device 20. The first water discharge side switching valve (open / close valve) 9 is attached to the first water discharge pipe 11 so as to be located between the connection point with the communication pipe 6 and the connection point with the second water discharge pipe 18. The first intake side switching valve (open / close valve) 10 is attached to the communication pipe 6. The second water discharge side switching valve (open / close valve) 17 is attached to the second water discharge pipe 18. The second water intake side switching valve (open / close valve) 16 is attached to the water supply pipe 7 so as to be located on the downstream side of the connection point with the second water discharge pipe 18.

  The first water discharge side switching valve 9 and the first water intake side switching valve 10 are used as an introduction destination of seawater heated by heat exchange with the auxiliary machine 310 in the reactor building 300, either of the water discharge channel 110 or the cooling facility 15. It is the switching device for selectively switching to. When the introduction destination of the seawater is the discharge channel 110, the control device 20 opens the first discharge side switching valve 9 and closes the first intake side switching valve 10. On the other hand, when the introduction destination of the seawater is the cooling facility 15, the control device 20 closes the first water discharge side switching valve 9 and opens the first water intake side switching valve 10.

  The second water discharge side switching valve 17 and the second water intake side switching valve 16 select the introduction destination of the seawater cooled by the cooling facility 15 to either the water intake path 102 or the water discharge path 110 (second water discharge pipe 18). It is the switching device for switching to. When the introduction destination of the seawater is the discharge channel 110, the control device 20 opens the second discharge side switching valve 17 and closes the second intake side switching valve 16. On the other hand, when the introduction destination of seawater is the intake channel 102, the control device 20 closes the second discharge side switching valve 17 and opens the second intake side switching valve 16.

  During normal operation (when the deviation of the temperature detected by the thermometers 19 and 21 is less than the set value and the water level detected by the water level gauge 8 is greater than or equal to the set water level), the first water discharge side switching valve 9 is open and the first water intake side The switching valve 10, the second water discharge side switching valve 17, and the second water intake side switching valve 16 are closed. As a result, the seawater pumped from the intake channel 102 by the pump 130 or the like and heated by the heat exchangers 212 and 312 and the condenser is discharged to the ocean 108 via the first water discharge pipe 11 and the water discharge channel 110.

  When it is confirmed that the deviation of the detected temperatures of the thermometers 19 and 21 exceeds the set value (set temperature) and the detected water level by the water level meter 8 is equal to or higher than the set water level, the control device 20 A signal is output to the water discharge side switching valve 9 and the first water intake side switching valve 10, the first water discharge side switching valve 9 is closed, and the first water intake side switching valve 10 is opened. As a result, the seawater heated by the auxiliary machines 310 and 210 and the condenser is introduced into the cooling facility 15 via the connecting pipe 6 and cooled. Further, the control device 20 outputs a signal to the second water discharge side switching valve 17 and the second water intake side switching valve 16, opens the second water discharge side switching valve 17, and closes the second water intake side switching valve 16. As a result, the seawater cooled by the cooling facility 15 is discharged from the water discharge channel 110 through the second water discharge pipe 18 and the first water discharge pipe 11. As described above, when it is confirmed that the temperature deviation of the thermometers 19 and 21 exceeds the set value, when the seawater is discharged from the water discharge channel 110 after being cooled by the cooling equipment 15, the temperature deviation during intake and drainage increases. And the influence of heated seawater on the environment can be reduced.

  When it is confirmed that the water level detected by the water level meter 8 is lower than the set water level, the control device 20 is connected to the first water discharge side switching valve 9 regardless of the deviation of the temperature detected by the thermometers 19 and 21. A signal is output to the first intake side switching valve 10, the first discharge side switching valve 9 is closed, and the first intake side switching valve 10 is opened. And a signal is output to the 2nd water discharge side switching valve 17 and the 2nd water intake side switching valve 16, the 2nd water discharge side switching valve 17 is closed, and the 2nd water intake side switching valve 16 is opened. Thus, as in the first embodiment, the seawater heated by the heat exchanger 312 or the like is cooled by the cooling facility 15 via the connection pipe 6 and discharged to the intake channel 102 via the water supply pipe 7. The

  Therefore, also in this embodiment, since the rise in seawater temperature in the intake channel 102 can be reduced without reducing the amount of seawater in the intake channel 102, the auxiliary machines 310 and 210 installed in the plant are continued. And can be cooled.

  In the above, when the temperature difference is detected by the thermometers 19 and 21 during normal operation and the temperature difference exceeds a predetermined set value, the changeover valves 9, 10, 16 and 17 are switched to supply seawater. Although the case where it led to the cooling facility 15 and cooled is described, when it is known in advance that the intake and discharge temperature difference is increased in a predetermined operation, the operation operation start signal is transmitted to the control device 20, Thereby, the switching operation of the switching valves 9, 10, 16, and 17 may be performed. In this way, it is possible to respond faster than detecting the temperature difference with the thermometers 19 and 21. As an operation operation in which the temperature difference between intake and drainage increases, there is so-called backwashing in which the inside of the heat transfer pipe is washed by reversing the flow path of seawater led to the condenser heat transfer pipe. At the time of backwash operation, the temperature difference between intake and discharge increases due to an increase in the pressure loss of the seawater channel led to the condenser.

  In each of the above-described embodiments, the case where a cooling tower is used as the cooling facility 15 has been described. However, instead of the cooling tower, an end of the water supply pipe 7 on the side of the intake passage 102 like the water supply pipe 7 shown in FIG. It is good also as what is provided with a watering nozzle in a part, and cools seawater by spraying seawater toward the intake channel 102 from the said watering nozzle. Furthermore, as another air cooling method that can replace the cooling tower, a heat pump having a compressor that is operated by an emergency power source that can be used even in the event of an earthquake or tsunami is installed, and seawater is cooled by the heat pump. good.

  Further, the present invention is not limited to the above-described embodiment, and includes various modifications within the scope not departing from the gist thereof. For example, the present invention is not limited to the one having all the configurations described in the above embodiment, and includes a configuration in which a part of the configuration is deleted. In addition, part of the configuration according to one embodiment can be added to or replaced with the configuration according to another embodiment.

  Furthermore, each configuration related to the control device 20 and the functions and execution processing of each configuration are realized by hardware (for example, logic for executing each function is designed by an integrated circuit). You may do it. The configuration related to the control device 20 may be a program (software) that realizes each function related to the configuration of the control device 20 by being read and executed by an arithmetic processing device (for example, a CPU). Information related to the program can be stored in, for example, a semiconductor memory (flash memory, SSD, etc.), a magnetic storage device (hard disk drive, etc.), a recording medium (magnetic disk, optical disc, etc.), and the like.

  6 ... Communication piping, 7 ... Water supply piping, 8 ... Water level gauge, 9 ... Discharge side switching valve, 10 ... Intake side switching valve, 11 ... Discharge piping, 15 ... Cooling equipment, 16 ... Intake side switching valve, 17 ... Discharge side Switching valve, 18 ... Discharge pipe, 19, 21 ... Thermometer, 20 ... Control device, 100 ... Weir, 102 ... Intake channel, 108 ... Ocean, 110 ... Discharge channel, 130 ... Pump, 200 ... Turbine building, 210, 310 ... Auxiliary machine, 212, 312 ... Heat exchanger, 300 ... Reactor building

Claims (4)

An intake channel where seawater taken from the sea is stored;
A pump for pumping seawater in the intake channel as cooling water for auxiliary equipment in the reactor building;
A nuclear power plant, comprising: a cooling facility for exchanging heat with the auxiliary equipment and cooling the seawater heated with air to cool the seawater and returning the cooled seawater to the intake channel. In the nuclear power plant according to claim 1,
A water discharge pipe for introducing seawater heated by heat exchange with the auxiliary equipment in the reactor building into the water discharge channel;
A pipe for connecting the water discharge pipe and the cooling equipment, and a communication pipe for introducing seawater heated by heat exchange with the auxiliary equipment in the reactor building from the water discharge pipe to the cooling equipment;
Nuclear power further comprising a switching device for selectively switching the introduction destination of seawater heated by heat exchange with the auxiliary equipment in the reactor building to either the water discharge channel or the bypass channel Power plant. In the nuclear power plant according to claim 2,
A water level sensor for detecting the level of seawater in the intake channel;
When the water level detected by the water level sensor reaches less than a set value, a signal is output to the switching device, and the introduction destination of the seawater heated by the auxiliary equipment in the reactor building is switched from the discharge channel to the communication pipe. A nuclear power plant, further comprising a control device. In the nuclear power plant according to claim 2 or 3,
A pipe connecting the cooling facility and the intake channel, and a water supply piping for introducing seawater cooled by the cooling facility into the intake channel;
A pipe connecting the water supply pipe and the water discharge pipe, and another water discharge pipe for introducing seawater cooled by the cooling facility into the water discharge path;
Another switching device for selectively switching the introduction destination of the seawater cooled by the cooling facility to either the water supply pipe or the other water discharge pipe;
A temperature sensor for detecting a temperature deviation between seawater in the intake channel and seawater passing through the discharge channel,
The water discharge pipe is further introduced with seawater heated by steam in the turbine building auxiliary machine and condenser,
The control device outputs a signal to the switching device when the detected water level by the water level sensor is equal to or higher than a set value and a temperature deviation detected by the temperature sensor exceeds a set value, and introduces seawater in the discharge pipe. A nuclear power plant characterized in that the destination is switched from the discharge channel to the communication pipe, and a signal is output to the other switching device to switch the introduction destination of the seawater cooled by the cooling facility to the other discharge pipe. plant.

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