JP2020012768A - Reactor cooling system and operation method thereof - Google Patents

Abstract

To provide a reactor cooling system capable of diversifying means of injecting high-pressure water into a pressure container and means of removing heat, and an operation method thereof.SOLUTION: A reactor cooling system comprises: a reactor pressure container 1; a main steam pipe 2; a main steam isolation valve 3; power generation turbines 4, 5; a condenser 7; a water supply pipe 10a; a water supply pump 16; a water supply pump driving steam turbine 14; a first piping route B; a second piping route A; a third piping route D; a driving steam switching valve 17 to which the first piping route B and the second piping route A are connected, and which switches the steam used by the water supply pump driving steam turbine 14 to the steam from the first piping route B or the second piping route A; and a controller 27 that closes the main steam isolation valve 3 when the reactor is shut down, and drives the water supply pump driving steam turbine 14 with steam from the second piping route A.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a reactor cooling system and a method of operating the same.

  2. Description of the Related Art Conventionally, in a nuclear power plant, a nuclear reactor includes a reactor in which a nuclear fuel is loaded, a reactor pressure vessel having a hermetically sealed structure (hereinafter, referred to as a pressure vessel), and a reactor containment vessel having a hermetically sealed structure including the pressure vessel. (Hereinafter, referred to as a containment vessel).

  Steam generated by the heat of the nuclear fuel in the pressure vessel is sent from the pressure vessel to the power generation turbine through the main steam pipe, and drives the power generation turbine. Thereafter, the steam is condensed by heat exchange in a condenser in which seawater or river water is supplied as secondary cooling water by a circulating water pump.

  The condensed water is sent to a feed water heater using the condensate pump as a heat source using the bleed air of the turbine as a heat source, heated by heat exchange with the bleed air of the turbine, and pressurized by a water pump driven by a steam turbine or an electric motor to be pressurized. Return inside. Exhaust steam from a steam turbine driven feedwater pump is returned to the condenser and becomes part of the feedwater. This circulation loop is called the reactor cooling system.

  When the reactor is shut down, the reactor cooling system is isolated by closing the main steam isolation valve, and the decay heat generated in the reactor core is the water that flows from the auxiliary cooling system through the heat exchanger through the cooling water in the pressure vessel. It is removed by the residual heat removal system (cooling mode when stopped) for cooling. The cooling water sent from the auxiliary cooling system is cooled by circulating a pump through a heat exchanger that uses seawater or river water as secondary cooling water via a heat exchanger.

  In addition, the auxiliary equipment cooling system supplies cooling water to the residual heat removal system, the cooling system at the time of reactor isolation that sends cooling water to the pressure vessel with a steam turbine driven water supply pump, and the low pressure injection system that uses an electric pump. And cooling of equipment including the above-mentioned cooling / water injection system and cooling of various pump bearings.

  For example, when cooling the reactor core during an accident such as a pipe break in the reactor cooling system, the steam generated in the reactor core is diffused and condensed into the suppression pool in the containment vessel, and the temperature of the suppression pool water rises. . However, the pressure suppression pool water can be radiated to the seawater or river water of the heat sink by using the residual heat removal system (pressure suppression room pool water cooling mode) and the auxiliary cooling system.

In the design of a nuclear reactor, measures are taken based on the concept of five layers of deep protection from the viewpoint of preventing occurrence of abnormalities, preventing abnormal expansion, and mitigating the effects of accidents.
Deep protection First layer is for prevention of occurrence of abnormal state or failure, second layer is for detection of abnormal state or failure and control of abnormal operation, third layer is for prevention of abnormal state corresponding to design standard accident, and fourth layer is for The fifth layer is for prevention of severe accidents such as core melting and mitigation of the effects. The fifth layer is disaster prevention measures for the surrounding residents against abnormal release of radioactive materials or radiation.

  In the third layer, in the event of a long-term total power loss event in which the function of the residual heat removal system is lost, water injection cooling with various and multiple facilities and cooling of the reactor with heat sinks are used to enhance deep protection. It is a requirement.

  As measures against this, various high-pressure water injection means were added on a design basis, and the power supply (DC) of the cooling system during reactor isolation was strengthened when the design was expanded. Here, the cooling system at the time of reactor isolation means that the turbine pump is turned by steam generated in the pressure vessel core when the reactor is stopped, and the condensate makeup water and the pressure suppression pool water of the reactor cooling system are injected into the pressure vessel. Equipment.

  Further, as a conventional technique for strengthening the power supply of the reactor isolation cooling system, a generator is attached to a steam turbine that drives a water injection pump of the reactor isolation cooling system shown in Patent Document 1, and a storage battery of a DC power supply is charged. A method for extending the discharge time of a DC power supply is disclosed.

JP-A-10-260294

By the way, in the third layer of deep protection, it is necessary to cool water by using various and multiple facilities and to cool the reactor by using a heat sink. As a countermeasure, it is effective to construct a new cooling means and use a conventional cooling means in addition to the conventional technology.
On the other hand, in Patent Literature 1, the cooling water of the suppression pool is injected into the pressure vessel, and the steam generated in the core is diffused from the relief valve of the main steam pipe into the suppression pool water to be condensed and circulated. Can be cooled.

  However, when the entire power supply is lost, the pressure suppression pool water is not cooled due to the loss of the functions of the residual heat removal system (pressure suppression room pool water cooling mode) and auxiliary equipment cooling system, and the pool water temperature rises. There is a problem that vapor condensation in the suppression pool becomes difficult.

In order to solve this problem, the above-described alternative heat exchanger vehicle that removes heat from seawater or river water as a heat sink is used. Similarly, alternative heat exchanger vehicles are used for alternative high-pressure water injection equipment for heat dissipation. However, from the viewpoint of diversification of core cooling means, not only portable equipment using vehicles but also heat removal means for heat sinks It is also necessary to increase the number of options and strengthen the power supply of emergency equipment.
A DC power supply is used for instrumentation control of a commercial / emergency reactor cooling system, including a reactor isolation cooling system, and Patent Document 1 supplies DC power using a generator attached to a turbine. .

On the other hand, when the cooling system at the time of reactor isolation, the residual heat removal system, and the high-pressure water injection means are operated continuously, it is necessary to operate the auxiliary cooling system to perform air conditioning and cooling of bearings.
The present invention has been made in view of the above situation, and in the case of a long-term total power loss event assumed in the third layer of deep protection, an atom that diversifies the high pressure water injection means to the pressure vessel and the heat removal means to the heat sink. An object of the present invention is to provide a furnace cooling system and an operation method thereof.

  In order to solve the above-described problems, a reactor cooling system according to a first aspect of the present invention includes a reactor pressure vessel containing a core for loading a fuel assembly, and a steam connected to the reactor pressure vessel and generated in the reactor core. A main steam pipe, a main steam isolation valve provided in the main steam pipe, a power generation turbine to which the steam sent by the main steam pipe is supplied, and a heat exchanger for passing the steam passing through the power generation turbine. A condenser condensed in the condenser, a water supply pipe for supplying cooling water condensed in the condenser to the reactor pressure vessel, and a water supply pump provided in the water supply pipe for supplying cooling water to the reactor pressure vessel A steam turbine for driving a feed water pump that drives the feed water pump; a first piping path that guides and drives the extracted steam from the turbine for power generation to the steam turbine for driving the feed water pump; Upstream from the steam valve A second piping path for branching off the main steam pipe and guiding the steam generated in the core to the feed water pump driving steam turbine, and driving the steam discharged from the feed water pump driving steam turbine. A third piping route leading to the vessel, the first piping route and the second piping route being connected, and a steam used by the feed water pump driving steam turbine being extracted steam from the first piping route. And a driving steam switching valve for switching to steam from the second piping route, and when the reactor is stopped, the main steam isolation valve is closed and the driving steam switching valve is switched to the second piping route side. And a control device for driving the feed water pump driving steam turbine by the steam supplied through the second pipe route.

  A method for operating a reactor cooling system according to a second aspect of the present invention is the method for operating a reactor cooling system according to the first aspect of the present invention, wherein the control is performed when the core cooling function of the reactor is lost or when all power supply devices are lost. After the main steam isolation valve is closed by the device, the on-off valve of the emergency steam supply pipe is opened, and the drive steam switching valve is switched to the emergency steam supply pipe side to drive the feed pump with main steam. Driving a steam turbine

  Advantageous Effects of Invention According to the present invention, a reactor cooling system capable of realizing diversification of high-pressure water injection means to a pressure vessel and heat removal means to a heat sink in a long-term total power loss event assumed in the third layer of deep protection and its operation We can provide a method.

FIG. 2 is a system diagram illustrating an operation during a normal operation of the reactor cooling system according to the first embodiment of the present invention. FIG. 3 is a system diagram illustrating an operation when all power is lost according to the first embodiment of the present invention. FIG. 10 is a system diagram illustrating an operation when all power is lost according to the second embodiment. FIG. 9 is a system diagram illustrating an operation of the reactor cooling system according to a modification of the second embodiment when all power is lost. FIG. 10 is a system diagram illustrating an operation of the reactor cooling system according to the third embodiment when all power is lost.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as appropriate.
The present invention relates to a power supply facility and a reactor cooling facility of a nuclear power plant. More specifically, the present invention relates to a reactor cooling system capable of injecting cooling water and supplying power by driving a steam turbine and removing heat of the reactor to the outside even when all AC power is lost, and a method for operating the reactor cooling system.

From the viewpoint of securing core cooling means when all AC power is lost, it is necessary to strengthen the power supply of emergency equipment as well as portable equipment using vehicles, and to increase the options for accident convergence measures.
In addition, diversification of heat sinks is also important in order to secure final heat radiation means in the event of a disaster or accident.

Further, since a motive power supply is required for driving the pump of the auxiliary cooling system, diversification of the means for supplying the motive power is also effective for improving safety in the event of a disaster or accident.
Therefore, diversification and multiplexing of the cooling means of the present invention are intended to enhance the power supply when a long-term total power loss event occurs after the reactor scram, add high pressure water injection means, and add heat removal means to the heat sink. It is.

  A reactor cooling system according to an embodiment of the present invention described below includes a fast breeder reactor in addition to a light water reactor such as a boiling water reactor (BWR) and a pressurized water reactor (PWR). And various types of nuclear reactors such as a new conversion reactor.

  In the following, an example in which the reactor cooling system of the present invention is applied to a BWR as a representative example will be described. However, as long as the gist of the present invention is not changed, it is possible to apply a modification to the reactor cooling system of the above various reactor types. is there.

<< First Embodiment >>
FIG. 1 is a system diagram illustrating an operation during a normal operation of the reactor cooling system R1 according to the first embodiment of the present invention.

Table 1 shows the states of the respective valves in FIG. 1 to FIG. 5 described later, and Table 2 shows the states of the steam source switching valves (driving steam switching valves) 17 and 37 of the three-way valve.

Table 3 shows reference numerals used in FIGS.

  Reference numerals 81 and 82 in FIGS. 1 to 5 denote check valves.

A pressure vessel 1 containing a core loaded with nuclear fuel is installed inside a containment vessel not shown in FIG.
The reactor cooling system R <b> 1 mainly includes a pressure vessel 1, a high-pressure turbine 4 and a low-pressure turbine 5 of a power generation turbine, a generator 6, and a condenser 7.

The pressure vessel 1 has a core containing a core for loading a fuel assembly (not shown), and boil cooling water to produce high-temperature and high-pressure steam.
The high-pressure turbine 4 and the low-pressure turbine 5 are driven to rotate by steam from the pressure vessel 1.

The generator 6 is rotated and driven by the high-pressure turbine 4 and the low-pressure turbine 5 to generate power. The power generated by the generator 6 is transmitted to a power consuming area.
In the condenser 7, the steam that has passed through the high-pressure turbine 4 and the low-pressure turbine 5 is cooled by the heat exchanger 20 of the condenser 7, condensed, and returned to the cooling water. In the condenser 7, secondary cooling water W2 such as seawater or river water for cooling steam is supplied to the heat exchanger 20 through the secondary cooling water passage 8a.

The water condensed in the condenser 7 is returned to the pressure vessel 1 through a water supply flow path (water supply pipe) 10a.
The circulating water pump 9 generally has a large capacity and is installed in a circulating water pump building near a heat sink. However, at the time of a nuclear reactor accident, only the decay heat needs to be removed, and the required circulating flow rate is small.

  Therefore, apart from the circulating water pump 9 for sending the secondary cooling water W2 from near the heat sink, a self-priming, high-lift auxiliary circulating water pump 19 is provided near the condenser 7 installed in the turbine building. You may. By providing the auxiliary circulating water pump 19, it is possible to reduce the power consumption at the time of the accident by providing the auxiliary circulating water pump 19 that is efficient with respect to the required circulation flow rate at the time of a nuclear reactor accident. In addition, in the event of a tsunami or other flood, even if the circulating water pump building near the heat sink is damaged, a healthy pump can be secured inside the turbine building. Therefore, the reliability of the reactor safety equipment when the core cooling function of the reactor is lost or when all the power supply devices are lost is improved.

Although not shown, a water supply tank for the auxiliary circulating water pump 19 may be provided inside the turbine building or outdoors near the turbine building, and the cooling water may be supplied to the water supply tank by a fire pump or the like to secure a water source.
Alternatively, a small-capacity motor-driven auxiliary circulating water pump 19 may be attached to the secondary cooling water flow passage 8a in parallel with the circulating water pump 9 and driven by the power source PE (FIG. 2). When the auxiliary circulating water pump 19 is installed in the circulating water pump building, a pump of a waterproof specification may be used in consideration of a tsunami or the like. For example, a waterproof cover is provided on the auxiliary circulating water pump 19, and a waterproof cable and a waterproof connector are used for wiring of the auxiliary circulating water pump 19. Thereby, it is possible to suppress the operation stop and the operation inhibition due to the flood of the auxiliary circulating water pump 19.

<Normal operation of reactor cooling system R1>
The normal operation of the reactor cooling system R1 will be described. 1 to FIG. 5 represents an electric motor (motor), and G represents a generator (generator).
Steam S1 generated in the core of the pressure vessel 1 passes through a main steam pipe 2 provided with a main steam isolation valve 3 and is sent to a high-pressure turbine 4 and a low-pressure turbine 5 of a power generation turbine. Then, the high-pressure turbine 4 and the low-pressure turbine 5 of the power generation turbine are rotationally driven by the heat energy of the steam S1.

Power is generated by the generator 6 by the power of the power generation turbine. The steam exiting the low-pressure turbine 5 enters the condenser 7 and is cooled and condensed by the secondary cooling water W2 flowing through the heat exchanger 20 by one or more circulating water pumps 9.
Here, seawater, river water, or the like is used as the secondary cooling water W2 as described above. Seawater and river water remove the waste heat excluding the nuclear fuel heat generated in the reactor core, excluding the work done by the turbine. The seas and rivers correspond to heat sinks (removal sources for heat sources) for the nuclear reactor.

  The primary cooling water W1 condensed in the condenser 7 passes through a water supply pipe 10a connected to the condenser 7 and is sent by a condenser pump 11 to feedwater heaters 12a and 12b. Then, the primary cooling water W1 heated by the feedwater heaters 12a and 12b is pressurized by the feedwater pump 16 or the feedwater pump 31 and supplied to the pressure vessel 1 through the feedwater pipe 10b.

  Here, the feed water heaters 12a and 12b are installed for the purpose of raising the feed water temperature in order to improve the thermal efficiency in the core. Steam S2 and S3 (paths (B) and (C) in FIG. 1) extracted from the power generation turbines (4 and 5) are used for heating the feedwater in the feedwater heaters 12a and 12b.

  The drain water in which the steams S3 and S2 are condensed in the feed water heaters 12a and 12b respectively passes through the condensed water drain passage 13 and the water supply passage 22, and is sent to the condenser 7 by the feed water heater drain pump 21. The feedwater heaters 12a and 12b are provided in a plurality of stages along the feedwater pipe 10a in order to increase the thermal efficiency corresponding to the temperature of the extracted steam of the turbine (4, 5). Although not shown, a high-pressure feed water heater may be provided in the feed pipe 10b at the subsequent stage of the steam turbine drive feed pump 16 or the feed pump 31.

A steam pump driven type is used for a large furnace and an electric motor driven type is used for a small furnace, but a plurality of units are generally used in combination of both types for safety reasons.
Hereinafter, the steam turbine drive water supply pump 16 and the electric motor drive water supply pump 31 may be abbreviated to the water supply pump 16 and the water supply pump 31 as appropriate.

  The feed water pump 16 shown in FIG. 1 is driven by the steam turbine 14 using the extracted steam S2 of the high-pressure turbine 4 (path (B) in FIG. 1). The exhaust steam after driving the steam turbine 14 is guided to the condenser 7 (path (D) in FIG. 1). The “first piping route” corresponds to the route (B), the “second piping route” corresponds to the route (A) described below, and the “third piping route” corresponds to the route (D). I do. In addition, the feed water pump driving steam turbine 14 is appropriately abbreviated as the steam turbine 14.

<Emergency configuration for when all power is lost>
FIG. 2 is a system diagram illustrating an operation when all power is lost according to the first embodiment of the present invention.
The reactor cooling system R1 of the first embodiment has the following configuration as an emergency configuration for when all power is lost in addition to the configuration of the reactor cooling system described above.

  A generator 15 is provided in the steam turbine 14 of the steam turbine drive water supply pump 16. Then, an inverter 25 is provided, and the inverter 25 adjusts the generated power of the generator 15 and supplies an AC power supply PE (see FIG. 2) to the condensate pump 11, the circulating water pump 9, and the electric motor drive water supply pump 31. . In addition, a DC power supply 26 is provided. The DC power supply 26 extracts a part of the power of the inverter 25, rectifies the power, and supplies DC power by connecting a primary battery in parallel. That is, the DC power supply 26 is provided with a converter and a primary battery, and is configured to rectify a part of the AC power of the inverter 25 by the converter and store the rectified power in the primary battery.

An emergency steam supply pipe 59 is provided upstream of the main steam isolation valve 3 of the main steam pipe 2. Then, the steam in the reactor pressure vessel 1 is extracted through the on-off valve 23 of the emergency steam supply pipe 59.
Further, a steam source switching valve 17 for selectively switching the steam used by the steam turbine 14 between the bleed air (path (B)) of the power generation turbine (4) and the steam (path (A)) of the emergency steam supply pipe 59. Is provided. Then, the steam source switching valve 17 is connected to the steam turbine 14 that drives the steam turbine drive water supply pump 16. The exhaust steam of the steam turbine 14 is guided to the condenser 7 through a flow path (path (D)).
In an emergency such as when all power is lost, although not shown, all control rods are inserted into the core. However, even in that state, decay heat of about 10% of the rated output is generated from the core. In the present embodiment, even when the entire power supply is lost, this heat is surely removed and the reactor is brought to a cold shutdown.

  In addition, as a control device, the on-off valve 23 is opened and closed, the steam source switching valve 17 is switched, the condensate pump 11 and the auxiliary circulating water pump 19 are started and stopped, and the power of the pumps (11, 19) is set to an existing power source. A control device 27 is provided for performing control for selectively switching between a power supply and a power supply for the inverter 25.

<Operation when all power supply units are lost>
After the steam isolation valve 3 is closed, when the entire power supply device is lost, the emergency steam supply pipe 59 is opened and closed by the normal control device or by the control device 27 when the normal control device loses its function. The valve 23 is opened. Then, the steam source switching valve 17 is switched to the emergency steam supply pipe (path (A)) to drive the steam turbine 14 with the main steam. By the rotation of the steam turbine 14, the generator 15 attached to the steam turbine 14 generates electric power. As a result, power is supplied to the condensate pump 11 and the auxiliary circulating water pump 19 via the inverter 25, and the steam turbine drive water supply pump 16, the condensate pump 11, and the auxiliary circulating water pump 19 are operated. The steam turbine drive water supply pump 16 is driven by the steam turbine 14.

  The exhaust steam (path (D)) of the steam turbine 14 is condensed in the condenser 7. The condensed water is injected into the pressure vessel 1 through a water supply pipe 10a, a condensate pump 11, a steam turbine drive water supply pump 16, and a water supply pipe 10b. As a result, a circulating cooling system for the primary cooling water W1 for cooling the core is established. That is, there is no particular need for external water supply.

  On the other hand, the heat deprived from the primary cooling water W1 by the condensation of steam in the condenser 7 is transmitted to the secondary cooling water W2 sent from the heat sink to the heat exchanger 20 of the condenser 7 by the auxiliary circulating water pump 19. Is done. When the secondary cooling water W2 is discharged to the sea, a river, or the outside of the turbine building, heat generated in the core moves from the primary cooling water W1, to the secondary cooling water W2, and further to the heat sink, and cooling of the core is established. You.

The control device 27 controls a set value of a servo device (not shown) for controlling the rotation of the steam turbine 14 and a control signal CS for controlling the power of the electric motor-driven water supply pump 31, the condensate pump 11, the circulating water pump 9, and the auxiliary circulating water pump 19. Is output.
Here, the control of the pumps (31, 11, 9, 19, 21, etc.) takes precedence over the higher-level control signal CS0 while the higher-level control signal CS0 (FIG. 1) of the reactor is obtained, and the higher-level control through the controller 27. A signal obtained by converting the control signal CS0 into the control signal CS is used. As described above, when the upper control signal CS0 of the nuclear reactor is obtained, the control device 27 functions as a repeater.

The surplus generated power can be supplied to the power source in the reactor by the inverter 25 (PE in FIG. 2).
A part of the output of the inverter 25 is transmitted to the DC power supply 26 and rectified to generate DC power. This DC power is stored in a storage battery (not shown) included in the DC power supply device 26, and is supplied as a DC power supply DE1 used for instrumentation control of the control device 27. The surplus DC power of the DC power supply 26 is fed into the DC power supply in the reactor including the above-mentioned emergency core cooling system (DE2 in FIG. 2).

  While DC power is supplied to the host controller and the control function is maintained, the controller 27 receives the host control signal CS0 and starts the steam turbine 14 and the auxiliary circulating water pump 19, as shown in FIG. The control signal CS is relayed to pumps and automatic valves of the reactor cooling system.

  However, when the higher-level control device is stopped due to discharge of the storage battery and the higher-level control signal CS0 is cut off, the control device 27 operates independently to operate the steam turbine 14, the motor-driven water supply pump 31, and the condensate pump 11 The operation of the auxiliary circulating water pump 19 is controlled.

  In the first embodiment, the circulating water pump 9 and the circulating water pump 9 may be used instead of the auxiliary circulating water pump 19 to supply the secondary cooling water W2 if the water supply passage is sound. Since the flow rate and suction pressure of the cooling water W2 are different, it is necessary to understand that the flow rate / head characteristics of the pump deviate from the optimum points and the efficiency is reduced.

  As a configuration other than the above, a second emergency steam supply pipe 28 for extracting steam in the pressure vessel 1 from the upstream of the main steam isolation valve 3 of the main steam pipe 2 via the on-off valve 24 and the flow control valve 33a is provided. The second emergency steam supply pipe 28 communicates with the primary side of the condenser 7. If the amount of steam generated in the reactor core is excessive after the main steam isolation valve 3 is closed in a nuclear reactor accident, the control device 25 opens the on-off valve 24 and adjusts the opening of the flow control valve 33 a to adjust the steam turbine 14. Steam exceeding a necessary amount for driving may be diffused to the primary side of the condenser 7 and condensed. This allows efficient operation of the steam turbine 14.

In addition, the main steam pipe 2 is communicated with the main steam pipe 2 from the upstream side of the main steam isolation valve 3 via the on-off valve 24a and the flow control valve 33b. If the amount of steam generated in the reactor core is excessive after the main steam isolation valve 3 is closed in a nuclear reactor accident, the control device 27 opens the on-off valve 24a and adjusts the opening of the flow control valve 33b to adjust the steam. Steam exceeding a necessary amount for driving the turbine 14 may be passed through the main steam pipe 2.
Preferably, steam turbine drive feedwater pump 16 and steam turbine 14 are joined or connected via a clutch mechanism, and steam turbine 14 and generator 15 are joined or connected via a clutch mechanism. Thereby, the steam turbine 14 is set to any one of three modes, namely, a mode dedicated to driving the steam turbine drive water supply pump 16, a mode dedicated to power generation by the generator 15, and a mode combining drive of the steam turbine drive water supply pump 16 and power generation by the generator 15. You can select and use.

  According to the first embodiment, using the main steam of the nuclear reactor as a power, the condenser 7 which has been shut down in the event of an accident or a failure of important equipment, the steam turbine driven feed pump 16, the condensate pump 11 which has been stopped, By using the auxiliary circulating water pump 19, the heat of the core can be removed to the heat sink of seawater or river water.

In particular, it is possible to increase the means for removing heat from the core to the heat sink when all power supply of the nuclear power plant is lost. Therefore, it is possible to diversify a path for radiating the heat of the core to the external heat sink in the event of a total power loss.
Therefore, when the core cooling function of the reactor is lost or when all the power supply units are lost (SBO), the power supply for driving the pumps (31, 11, 9, 19, 21, etc.) and the auxiliary cooling system of the reactor cooling system R1 is used. In addition, the means for supplying DC power required for instrumentation control, the means for injecting water into the pressure vessel 1 and the means for removing heat to the heat sink can be diversified, and damage to the core can be suppressed.

Therefore, the reliability of the reactor safety equipment is improved, and the safety of the reactor is improved.
Further, even when the function of the higher-level control device is lost, the core can be cooled by forming an independent cooling loop, and the power generated by the steam turbine 14 is input to the power source of the reactor and the DC power source 26 and Since the power capacity of the reactor is increased, the reliability of the reactor safety equipment is improved, and the safety of the reactor is further improved.

<< Embodiment 2 >>
Embodiment 2 of the present invention will be described in detail with reference to FIGS. FIG. 3 is a system diagram illustrating an operation when all power is lost according to the second embodiment.
The reactor cooling system R2 of the second embodiment is different from the reactor cooling system R1 of the first embodiment in that a condensate pump 34 that is newly driven by a steam turbine 36 is provided in the water supply pipe 10a, and a generator 35 is attached to the drive shaft. Can be The power generated by the generator 35 is connected to the inverter 25.

  FIG. 3 illustrates an example in which a condensate pump 11 driven by an electric motor and a condensate pump 34 driven by a steam turbine 36 are used in parallel to feed water from the feedwater heaters 12a and 12b to the feedwater pumps (31 and 16). However, during normal operation of the reactor cooling system R2, only the condensate pump 11 may be used, and the condensate pump 34 may be activated when all power is lost. Alternatively, during normal operation, the steam source switching valve 37 is set to the path (B), the steam turbine 36 is driven using the extracted steam S2 of the high-pressure turbine 4 from the path (B), and the condensate pump 34 is constantly operated. You may.

  Further, the condensing pump 34 and the steam turbine 36 are joined via a clutch mechanism, and the steam turbine 36 and the generator 35 are joined via a clutch mechanism. Thus, the steam turbine 36 can be used by selecting any one of three modes, that is, the exclusive mode for driving the condensate pump 34, the exclusive mode for power generation of the generator 35, and the combined mode of driving the condensate pump 34 and power generation of the generator 35. .

When the entire power supply is lost after closing the main steam isolation valve 3 of the main steam pipe 2, the on-off valve 23 of the emergency steam supply pipe 59 is opened. Further, the steam source switching valve 17 and the steam source switching valve 37 are switched to the path (A).
Then, the steam turbine drive water supply pump 16 pressurizes and sends the cooling water to the pressure vessel 1 by the operation shown in the first embodiment. In addition, the condensate pump 34 sends the cooling water condensed in the condenser 7 from the feed water heaters 12 a and 12 b to the steam turbine drive feed pump 16. The condensate pump 34 is driven by a steam turbine 36 operated by steam passing through the path (A) of the steam source switching valve 37 and the pressure reducing valve 38.

  Further, the power generated by the generator 35 is sent to the inverter 25 and converted into a power source PE. The power source PE is supplied to the auxiliary circulating water pump 19, the electric motor driven water supply pump 31, and the condensate pump 11.

  In the second embodiment, the steam turbine drive water supply pump 16 and the condensate pump 34 can be operated by the main steam S1 when the total power supply is lost. Further, power can be generated by the two steam turbines 14 and 36. Therefore, it is possible to increase the capacity of the power source for driving the auxiliary circulating water pump 19 and other electric motor driven pumps (31, 11, 19, etc.). Further, when the steam turbine 14 breaks down, a power supply for driving other electric motor driven pumps (31, 11, 19, etc.) can be backed up.

<Modification of Second Embodiment>
FIG. 4 is a system diagram showing the operation of the reactor cooling system R21 according to the modification of the second embodiment when all power is lost.
In the reactor cooling system R21 of the modified example, a condensate pump 34 driven by a steam turbine 36 is provided in a water supply pipe 10a from the condenser 7, and a motor generator 60 is attached to a drive shaft of the condensate pump 34. . Thereby, the condensate pump 11 driven by the electric motor is omitted.

The steam turbine 36 and the motor generator 60 are connected via a clutch mechanism or connected.
During normal operation, the steam turbine 36 is stopped to disengage the clutch, and the condensate pump 34 is driven using the motor generator 60 as an electric motor.

  If the entire power supply is lost after closing the main steam isolation valve 3 of the main steam pipe 2, the on-off valve 23 of the emergency steam supply pipe 59 is opened. Then, steam is supplied from the path (A) to the steam turbine 36 via the pressure reducing valve 38. The steam turbine 36 is connected to the motor generator 60 and the condensate pump 34 by connecting a clutch. Thus, the condensate pump 34 can be driven by the main steam, and the generated power is transmitted to the inverter 25 using the motor generator 60 as a generator. In this modification, one condensing pump 34 can be used for both the electric motor drive pump during normal operation and the steam turbine drive pump when all power is lost by connecting and disconnecting the clutch.

  According to the above configuration, even when one of the steam turbines (14, 36) of the steam turbine drive feed water pump 16 and the condensate pump 34 fails, the other steam turbine generates power, and the power supply from the inverter 25. The PE can drive the motor drive water supply pump 31, the motor drive condensate pump 11, and the circulating water pump 9. Further, since the number of the motor driven condensate pumps 11 can be reduced, the economical efficiency of the installation of the nuclear reactor can be secured.

  In the second embodiment and the modified example, the capacity of the motive power source that can be used for the total power loss event is increased by the generator 35 and the motor generator 60. Therefore, the reliability of the reactor safety equipment is improved, and the safety of the reactor is improved.

<< Embodiment 3 >>
The reactor cooling system R3 according to the third embodiment of the present invention will be described in detail with reference to FIG. FIG. 5 is a system diagram illustrating an operation of the reactor cooling system R3 according to the third embodiment when all power is lost.
The reactor cooling system R3 according to the third embodiment includes a main steam S1 (path (A)) near the condenser 7 installed in the turbine building separately from the circulating water pump 9 that sends the secondary cooling water W2 from near the heat sink. ) Is provided with the auxiliary circulating water pump 19 driven by the steam turbine 56 which uses the steam turbine 56.

  A motor generator 55 is attached to a drive shaft of the steam turbine 56. The steam turbine 56 is connected to the emergency steam supply pipe 59 via the path (A).

  In the reactor cooling system R3, since the steam of the radioactive primary cooling water W1 from the pressure vessel 1 is used for the steam turbine 56, it is necessary to install the auxiliary circulating water pump 19 in a radiation protection section such as a turbine building. is there. In addition, when installed at a higher place than the circulating water pump (9) building such as the turbine (4, 5) building, a self-priming high effective suction head specification is used.

  In the reactor cooling system R3, when all power is lost after closing the main steam isolation valve 3 of the main steam pipe 2, the on-off valve 23 of the emergency steam supply pipe 59 is opened. Then, the steam source switching valve 17 connected to the steam turbine 14 and the steam source switching valve 37 connected to the steam turbine 36 are switched to the path (A). The steam turbine 56 communicates with the path (A), and does not require a steam source switching valve.

  In the reactor cooling system R3 of the third embodiment, the water supply pump 16 pressurizes and sends cooling water to the pressure vessel 1 by the operation shown in the first embodiment, and the condensate pump 34 performs the operation shown in the second embodiment. The cooling water condensed in the condenser 7 is supplied from the feed water heaters 12a and 12b to the steam turbine drive feed pump 16.

The electric power generated by the motor generator 55 is sent to the inverter 25, converted into an AC power supply PE, and supplied to the motor drive water supply pump 31 and the condensate pump 11.
In the third embodiment, the steam turbine drive water supply pump 16, the condensate pump 34, and the auxiliary circulating water pump 19 can be operated by the main steam when all power is lost. Further, power can be generated by the three units of the steam turbine 14, the steam turbine 36, and the steam turbine 56. Therefore, it is possible to increase the capacity of a power supply for driving other electric motor driven pumps (31, 11, 19, etc.). Further, when one or both of the steam turbine 14 and the steam turbine 36 fails, a power supply for driving other electric motor driven pumps (31, 11, 19, etc.) can be backed up.

  On the other hand, when the steam turbine 56 fails, the motor generator 55 is used as a motor with a power source generated by power generation by either the combination of the steam turbine 14 and the generator 15 or the combination of the steam turbine 36 and the generator 35 or both. I do. Thereby, circulation of the secondary cooling water W2 can be maintained. Alternatively, a second auxiliary circulating water pump driven by an electric motor may be provided in parallel with the auxiliary circulating water pump 19, and motive power may be supplied to the circulating water pump 9.

According to the third embodiment, the capacity of the motive power source that can be used for the total power loss event is further increased for the generators 15, 35 and the motor generator 55. Therefore, the reliability of the reactor safety equipment is improved, and the safety of the reactor is improved.
Further, when the steam turbine drive water supply pump 16 and the condensate pump 34 are out of order, the power supply for driving other electric motor drive pumps (31, 11, 19, etc.) can be backed up.

  Therefore, the reliability of the reactor safety equipment is improved, and the safety of the reactor is improved.

<< Other embodiments >>
1. Although various configurations have been described in the embodiments and the like, these configurations may be appropriately combined.

2. The configurations described in the above embodiments and the like are merely examples, and various forms and modifications are possible within the scope of the claims.

1 pressure vessel (reactor pressure vessel)
2 Main steam pipe 3 Main steam isolation valve 4 High pressure turbine (turbine for power generation)
5 Low-pressure turbine (power generation turbine)
Reference Signs List 6 generator 7 condenser 9 circulating water pump 10a water supply pipe 11 condensing pump 14 steam turbine (steam turbine for driving feedwater pump)
15 Generator 16 Steam turbine driven feedwater pump (feedwater pump)
17 Steam source switching valve (drive steam switching valve)
Reference Signs List 18 Pressure reducing valve 19 Auxiliary circulating water pump 20 Heat exchanger 23 On-off valve 24 On-off valve 25 Inverter 26 DC power supply 27 Control device 28 Bypass flow path (emergency steam supply pipe)
31 Electric motor driven water supply pump (water supply pump)
33a Flow control valve 34 Condensate pump 35 Generator 36 Steam turbine 37 Steam source switching valve (drive steam switching valve)
55 Motor generator 56 Steam turbine 59 Emergency steam supply pipe (second piping route)
60 Motor generator R1, R2, R21, R3 Reactor cooling system (reactor cooling system)
Route A (second piping route)
Route B (first piping route)
D route (third piping route)

Claims (15)

A reactor pressure vessel containing a core for loading the fuel assemblies;
A main steam pipe connected to the reactor pressure vessel and flowing steam generated in the reactor core,
A main steam isolation valve provided in the main steam pipe,
A power generation turbine to which steam sent by the main steam pipe is supplied;
A condenser that condenses the steam that has passed through the power generation turbine in a heat exchanger,
A water supply pipe for supplying cooling water condensed by the condenser to the reactor pressure vessel,
A feed pump provided in the feed pipe to feed cooling water to the reactor pressure vessel,
A feed water pump drive steam turbine that drives the feed water pump,
A first piping path that guides and drives the extracted steam from the power generation turbine to the feed water pump drive steam turbine,
A second piping path that branches from the main steam pipe upstream of the main steam valve of the main steam pipe and guides and drives steam generated in the core to the feed water pump driving steam turbine;
A third piping path for guiding exhaust steam from the feedwater pump drive steam turbine to the condenser;
The first piping route and the second piping route are connected, and the steam used for the feed water pump driving steam turbine is extracted from the first piping route and the steam from the second piping route. A driving steam switching valve for switching to and
When the reactor is stopped, the main steam isolation valve is closed, and the drive steam switching valve is switched to the second pipe route side, so that the water is supplied by steam supplied through the second pipe route. A reactor cooling system comprising a control device for driving a pump driving steam turbine. The reactor cooling system according to claim 1,
A condensate pump provided in the water supply pipe to supply cooling water,
A circulating water pump for supplying secondary cooling water for steam condensation to the heat exchanger,
A generator attached to the feed water pump drive steam turbine,
An inverter to which power generated by the generator is input and supplies power to the condensate pump, the circulating water pump, and the motor-driven water supply pump,
A DC power supply that supplies DC power by connecting a primary battery in parallel while taking out and rectifying a part of the power of the inverter,
The feedwater pump supplies cooling water to the reactor pressure vessel using the feedwater pump drive steam turbine or an electric motor as a drive source,
The control device opens and closes an on-off valve of the second piping path, starts and stops the condensate pump and the circulating water pump, and sets each power supply of the condensate pump and the circulating water pump to an existing power source. A reactor cooling system for controlling switching to a power supply from the inverter. The reactor cooling system according to claim 2,
A condensate pump driven by a condensate pump drive steam turbine that rotates with extracted steam from the power generation turbine,
A generator attached to the condensate pump drive steam turbine,
A drive steam switching valve for switching steam used by the condensate pump drive steam turbine to extraction of the power generation turbine and steam in the second piping path;
A reactor cooling system, wherein a power generation line of the generator is connected to the inverter, and a motive power from the inverter is connected to the motor-driven water supply pump. The reactor cooling system according to claim 2,
The feedwater pump and the feedwater pump drive steam turbine are connected via a clutch mechanism, the feedwater pump drive steam turbine and the generator are connected via a clutch mechanism, and the feedwater pump drive steam turbine is A reactor cooling system characterized in that the reactor cooling system is used by selecting any one of three modes, pump driving only, power generation only, and pump driving and power generation combined use. The reactor cooling system according to claim 2,
A reactor cooling system comprising: a motor-driven auxiliary circulating water pump that supplies secondary cooling water to the heat exchanger in parallel with a discharge-side flow path of the circulating water pump. The reactor cooling system according to claim 2,
A reactor cooling system, comprising: a steam turbine-driven auxiliary circulating water pump that supplies secondary cooling water to the heat exchanger in parallel with a discharge-side flow path of the circulating water pump. The reactor cooling system according to claim 2,
An emergency steam supply pipe that extracts steam from the reactor pressure vessel via an on-off valve and a flow control valve from upstream of the main steam isolation valve of the main steam pipe,
A reactor cooling system, wherein the emergency steam supply pipe communicates with a primary side of the condenser. The reactor cooling system according to claim 2,
An electric motor-driven auxiliary circulating water pump that supplies secondary cooling water to the heat exchanger in parallel with the discharge-side flow path of the circulating water pump,
A reactor cooling system, wherein a waterproof cover is provided on the auxiliary circulating water pump, and a waterproof cable and a waterproof connector are used for wiring of the auxiliary circulating water pump. The reactor cooling system according to claim 2,
An electric motor-driven auxiliary circulating water pump that supplies secondary cooling water to the heat exchanger in parallel with the discharge-side flow path of the circulating water pump,
The reactor cooling system, wherein the auxiliary circulating water pump is a self-priming high effective suction head type. A reactor pressure vessel containing a core for loading the fuel assemblies;
A main steam pipe connected to the reactor pressure vessel and flowing steam generated in the reactor core,
A main steam isolation valve provided in the main steam pipe,
A power generation turbine to which steam sent by the main steam pipe is supplied;
A condenser that condenses the steam that has passed through the power generation turbine in a heat exchanger,
A water supply pipe for supplying cooling water condensed by the condenser to the reactor pressure vessel,
A feed pump provided in the feed pipe to feed cooling water to the reactor pressure vessel,
A feed water pump drive steam turbine that drives the feed water pump,
A first piping path that guides and drives the extracted steam from the power generation turbine to the feed water pump drive steam turbine,
A second piping path that branches from the main steam pipe upstream of the main steam valve of the main steam pipe and guides and drives steam generated in the core to the feed water pump driving steam turbine;
A third piping path for guiding exhaust steam from the feedwater pump drive steam turbine to the condenser;
The first piping route and the second piping route are connected, and the steam used for the feed water pump driving steam turbine is extracted from the first piping route and the steam from the second piping route. A driving steam switching valve for switching to and
When the reactor is stopped, the main steam isolation valve is closed, and the drive steam switching valve is switched to the second pipe route side, and the steam supplied through the second pipe route causes A control device for driving a feed water pump drive steam turbine, comprising:
When the core cooling function of the reactor is lost or when all the power supply units are lost, the control device closes the main steam isolation valve, then opens the on-off valve, and moves the drive steam switching valve to the second piping path side. A method for operating a nuclear reactor cooling system, comprising switching the main steam to drive the feed water pump driving steam turbine. The method for operating a reactor cooling system according to claim 10,
The reactor cooling system comprises:
A condensate pump provided in the water supply pipe to supply cooling water,
A circulating water pump for supplying secondary cooling water for steam condensation to the heat exchanger,
A generator attached to the feed water pump drive steam turbine,
An inverter to which power generated by the generator is input and supplies power to the condensate pump, the circulating water pump, and the motor-driven water supply pump,
A DC power supply that supplies DC power by connecting a primary battery in parallel while taking out and rectifying a part of the power of the inverter,
The feedwater pump supplies cooling water to the reactor pressure vessel using the feedwater pump drive steam turbine or an electric motor as a drive source,
Reactor cooling by supplying power from the inverter to the condensate pump and the circulating water pump from the inverter to supply power to the condensate pump and the circulating water pump. How the system operates. The method for operating a reactor cooling system according to claim 11,
A condensate pump driven by a condensate pump drive steam turbine that rotates with extracted steam from the power generation turbine,
A generator attached to the condensate pump drive steam turbine,
A drive steam switching valve for switching steam used by the condensate pump drive steam turbine to extraction of the power generation turbine and steam in the second piping path;
When the core cooling function of the reactor is lost or when all power supply units are lost,
After the main steam isolation valve is closed, the control device opens the on-off valve of the second piping route, and switches the driving steam switching valve of the steam turbine driven condensate pump to the second piping route side to switch the main steam isolation valve. Driving the steam turbine for driving the condensate pump with steam, generating power with the steam turbine for driving the condensate pump, and supplying power from the inverter to the motor-driven water supply pump and the circulating water pump for operation. Characteristic method of operating the reactor cooling system. The reactor cooling system according to claim 11,
An electric motor-driven auxiliary circulating water pump that supplies secondary cooling water to the heat exchanger in parallel with the discharge-side flow path of the circulating water pump,
A power generator that generates power with the feed water pump driving steam turbine and the generator, supplies power power adjusted by the inverter to the auxiliary circulating water pump, and operates the feed water pump and the circulating water pump. How to operate the cooling system. The method for operating a reactor cooling system according to claim 11,
An auxiliary circulating water pump driven by a steam turbine that supplies secondary cooling water to the heat exchanger in parallel with the discharge-side flow path of the circulating water pump,
The steam generator for driving the feed water pump and the generator generate electric power, the power supply adjusted by the inverter is supplied to the auxiliary circulating water pump, and the steam used for the steam turbine for driving the condensate pump is mainly supplied via an on-off valve. A method for operating a reactor cooling system, characterized in that the steam is supplied from an upstream side of a main steam valve of a steam pipe. The method for operating a reactor cooling system according to claim 11,
An emergency steam supply pipe that extracts steam from the reactor pressure vessel via an on-off valve and a flow control valve from upstream of the main steam isolation valve of the main steam pipe,
The emergency steam supply pipe communicates with the primary side of the condenser,
After the main steam isolation valve is closed, the control device adjusts the opening of the flow rate control valve, and condenses in the condenser more steam than necessary to drive the feed water pump drive steam turbine. Characteristic method of operating the reactor cooling system.

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