JP2001349975A - Nuclear reactor water injection facility using steam turbine drive pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a facility for operating a water injection pump and a generator continuously and as long as possible by adjusting the amount of water injected into a reactor pressure vessel. SOLUTION: The generator 24 is connected to a steam turbine 1 driving the water injection pump 2 for injecting water into the reactor pressure vessel 8, and the opening of a valve 14 is adjusted to a small value in response to a signal sent from a flowmeter 22 indicating a low level of water in a reactor, and is adjusted to a large value in response to a signal indicating a normal level of water in the reactor. As the distribution of flow to the reactor pressure vessel 8 and to a bypass line 16 is adjusted by the opening of the valve 14, the time needed for the normal level of water in the pressure vessel to reach a high level is prolonged to extend the duration of operation of the injection pump 2, the steam turbine 1 and the generator 24.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reactor water injection system in which a steam turbine driven by steam from a reactor pressure vessel is used as a drive for a generator and a pump for injecting water into the reactor pressure vessel.

[0002]

2. Description of the Related Art Conventionally, as this kind of reactor injection equipment generally used, there is a reactor isolation cooling system (RCIC) of a boiling water reactor (BWR) plant. As shown in FIG. 2, this water injection equipment transfers a part of the steam generated in the reactor pressure vessel 8 installed in the reactor containment vessel 9 to the steam turbine 1 through the pipe 3. The cooling water in the condensate storage tank 10 is supplied to the reactor pressure vessel 8 via pipes 5 and 6 by driving the steam turbine 1 to activate the cooling system water injection pump 2 when the reactor is isolated. It is configured to inject water.

[0003] In the cooling system equipment at the time of reactor isolation of the boiling water nuclear power plant, it is necessary to adjust the amount of water injected into the reactor pressure vessel 8. This is because it is necessary to keep the water level in the reactor pressure vessel 8 constant. As a conventionally used method, a valve 23 capable of adjusting a steam flow rate is provided at the inlet of the steam turbine 1, the rotation of the turbine is controlled by adjusting the steam flow rate to the steam turbine 1, and cooling at the time of reactor isolation is performed. The method of driving the system injection pump 2 and the installation of a valve 7 capable of adjusting the flow rate at the outlet of the cooling system injection pump 2 at the time of isolation of the reactor, and the opening degree of the valve 7 capable of adjusting the flow rate are adjusted. There is a method of adjusting the amount of water injected into the furnace pressure vessel 8.

[0004] For example, as disclosed in Japanese Patent Application Laid-Open No. 6-201883, the cooling system injection pump 2 when the reactor is isolated.
Is generally controlled by a valve 7 provided at the discharge port of the water injection pump 2 and capable of adjusting the flow rate.

Further, as shown in FIG. 2 of Japanese Patent Application Laid-Open No. 9-113669, by installing a fluid coupling, which is a large device, between a water injection pump and a steam turbine, the number of revolutions is changed and the reactor pressure is changed. A method for adjusting the amount of water injected into a container is known.

[0006]

The flow rate adjusting method using the turbine inlet throttle device in the prior art described above is difficult to control and has a complicated structure. Also, in the method of adjusting the flow rate by providing a valve at the discharge port of the cooling system injection pump at the time of isolation of the reactor and adjusting the flow rate, a differential pressure occurs before and after the valve at which the flow rate can be adjusted, which may cause erosion. . further,
In the unlikely event that the valve is closed, there is a risk that water cannot be reliably injected into the reactor pressure vessel.

[0007] Further, when the amount of water injected into the reactor pressure vessel increases, the reactor water level reaches a level L8, which is a higher than normal water level, and the steam turbine trips and the injection pump automatically stops. Since the rotation of the generator stops, the power is lost. When the water level drops again, the pump is started. However, in such a state where the pump is repeatedly started and stopped, continuous and continuous supply of the generated power cannot be achieved. Therefore, it becomes difficult to supply emergency power required at the nuclear power plant in the event of a total loss of AC power.

In the case where the fluid coupling is adopted, the fluid coupling is a large-sized device, so that there is a situation where it cannot be installed in terms of space. Further, when it is desired to employ a small-sized turbine pump in which a steam turbine and a pump are integrated, the fluid coupling is an obstacle to downsizing, and therefore, the benefit of flow adjustment by the fluid coupling cannot be obtained.

An object of the present invention is to ensure that water is injected into a reactor pressure vessel without employing large equipment such as a fluid coupling, and that power is continuously supplied even in the event of a total loss of AC power. An object of the present invention is to provide a reactor water injection facility by a steam turbine driven pump that can supply the water.

[0010]

A first means for achieving the above object is a steam turbine driven by steam in a reactor pressure vessel, a water injection pump driven by the steam turbine, and a discharge from the water injection pump. Discharge pipe that guides water into the reactor pressure vessel, suction pipe that guides water in a water source to a suction port of the water injection pump, a generator driven by the steam turbine, and water injection in the discharge pipe. A steam turbine drive having a line of a pipe to be divided and a flow rate adjusting device provided in the line and adjusting a flow rate in the line by a reactor water level signal generated based on a water level in the reactor pressure vessel. This is a reactor water injection system using a pump.

According to the first means, the amount of water injected into the reactor pressure vessel is adjusted by adjusting the flow rate of the line branched from between the reactor pressure vessel and the injection pump based on the reactor water level signal. Thus, the water injection pump driven by the steam turbine can be operated continuously, and the generator driven by the steam turbine can be operated without stopping its rotation. In this way, the operation time of the pump and the generator driven by the steam turbine can be adjusted by adjusting the water injection flow rate, and if the operation period is lengthened, the number of times of starting and stopping each operating device can be reduced and reliability can be reduced. Performance can be improved.

The second means is also the first means, wherein the flow control device is capable of adjusting a valve opening by a reactor water level signal such that the higher the water level in the reactor pressure vessel, the larger the valve opening. This is a reactor water injection system using a steam turbine driven pump, which is a simple valve.

According to the second means, the operation of the first means can be performed by adjusting the opening of the valve, and the water level in the reactor pressure vessel rises, so that water is injected into the reactor pressure vessel. Before the water must be stopped, the opening of the valve is increased so that the amount of water injected per unit time is reduced, and until the water level in the reactor pressure vessel in which the injection must be stopped must be reached. The effect is obtained that the time is adjusted to be longer and the power generation period by the generator can be maintained longer.

[0014] Similarly, the third means is the first means or the second means, wherein the line is provided with a throttle device so that the line has a pressure loss, thereby suppressing excessive flow of the flow into the line. Reactor water injection equipment using a steam turbine driven pump.

According to the third means, in addition to the operation of the first means or the second means, even if the flow rate adjusting device for adjusting the flow rate in the line is malfunctioning, the throttle device narrows the flow path of the line. In addition, it is possible to suppress the effect of excessively diverting into the line, and to prevent the water injection into the reactor pressure vessel from being lost, thereby ensuring the safety.

A fourth means is a reactor water injection by a steam turbine driven pump provided with a check valve in the first means, the second means or the third means, the flow line being provided with a check valve so as to stop the flow to the discharge pipe side. Equipment.

According to the fourth means, in addition to the action of the first means, the second means, or the third means, the backflow in the line is prevented by the check valve, and the unexpected flow rate is reduced by the reactor pressure. By acting to prevent the inflow into the container, the possibility of an obstacle caused by providing the line branched from the discharge pipe is eliminated.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. An example of a water injection system to which the present invention is applied is a reactor isolation cooling system (RCIC) of a boiling water reactor (BWR) plant. This water injection system is shown in Fig. 1,
4, 5 and 6 have the following common configuration.

That is, part of the steam generated in the reactor pressure vessel 8 installed in the reactor containment vessel 9 is guided to the steam turbine 1 via the pipe 3 by opening the valve 25, and The steam turbine 1 is driven. When the steam turbine 1 is driven, the cooling system injection pump 2 at the time of reactor isolation connected to the steam turbine 1 is started. At this time, valve 2
0 is open.

Thus, the cooling water in the condensate storage tank 10 is injected into the reactor pressure vessel 8 through the suction pipe 5 and the discharge pipe 6. Since the steam turbine 1 is driven during such water injection, the generator 24 connected to the steam turbine 1 is also driven to perform a power generation operation. The power generated by the power generation action is distributed to each device such as a measuring device that requires power even when the reactor is isolated.

The steam used in the steam turbine 1 is condensed, passes through a pipe 4, and is discharged as a non-condensed steam through a pipe 4 to a suppression pool 11 in a reactor containment vessel, where it is condensed. It is temporarily stored in the suppression pool 11. The pool water containing the condensed water in the suppression pool 11 is connected to the suction pipe side via a valve 19.

When the water in the condensate storage tank 10 is insufficient for water injection into the reactor pressure vessel, the valve 19 is opened and directed to the water injection pump 2 side so as to function as the next water source. It is sucked and injected into the reactor pressure vessel.

A test line 12 is provided with a valve 26 in the middle thereof, and the valve 26 is not opened except for the test.

FIGS. 1, 4, 5, and 6 show a reactor water injection facility characterized in that the amount of water injected into the reactor pressure vessel 8 is adjusted by providing a branch line or a bypass line of piping. Are shown. FIG. 1 shows an example in which a first embodiment of FIG. 1 is provided with a bypass line 16 having a pipe extending from between the water injection pump 2 and the reactor pressure vessel 8 to the vicinity of the water injection pump 2 suction port.

In FIG. 1, one of the bypass lines 16 is connected in the middle of the discharge pipe 6, and the other is connected to the suction pipe 5. In the middle of the bypass line 16, from the discharge pipe 6 side, a throttle device 13, a valve 1 whose valve opening is adjustable
4, the check valve 15 is installed. The check direction of the check valve is determined so as to stop the flow from the bypass line 16 to the discharge pipe 6.

By providing the throttle device 13 with a pressure loss in the flow in the bypass line 16, the pump discharge flow is prevented from being excessively bypassed. Also, the reactor pressure vessel 8
By adjusting the opening degree of the valve 14 whose valve opening degree can be adjusted by a reactor water level signal issued from a flow meter 22 for measuring the water level in the reactor, a bypass branched from between the reactor pressure vessel 8 and the injection pump 2. It is possible to adjust the flow rate of the line 16. By the adjustment, the amount of water injected into the reactor pressure vessel 8 is adjusted, and the generator 24 can be operated without stopping its rotation. Further, the check valve 15 prevents backflow to the bypass line 16.

As described above, when the fluid coupling is not installed,
Alternatively, even if it cannot be installed, the reactor pressure vessel 8
It is possible to adjust the amount of water injected into the water. Further, even when a steam turbine without a fluid coupling and a small RCIC turbine pump integrated with a pump are used, the amount of water injected into the reactor pressure vessel 8 can be adjusted without deteriorating the conventional reliability. . When this small RCIC turbine pump is used, the space in the reactor building that houses them can be reduced, so that the cost can be reduced.

Next, a second embodiment shown in FIG. 4 will be described.
As shown in FIG. 4, one of a bypass line 17 is connected to a discharge pipe 6 between the water injection pump 2 and the reactor pressure vessel 8, and the other is connected to the suppression pool 11. As in the first embodiment, the valve opening degree of the bypass line 17 is controlled by a reactor water level signal generated from a throttle device 13 and a flow meter 22 for measuring the water level in the reactor pressure vessel 8 from the discharge pipe 6 side. Adjustable valve 14, check valve 15
Is installed in the bypass line 17.

By providing the throttle device 13 with a pressure loss, the pump discharge flow is prevented from being excessively bypassed. In addition, by adjusting the opening of the valve 14 whose valve opening can be adjusted by the reactor water level signal, the bypass line 17 is controlled.
To control the inflow of water into the suppression pool 11
Return to Further, the check valve 15 enables the bypass line 1
The backflow from 7 to the discharge pipe 6 is prevented.

Thus, the amount of water injected into the reactor pressure vessel 8 is adjusted, and the generator 24 can be operated without stopping its rotation. In this way, even when the fluid coupling is not installed or cannot be installed, the amount of water injected into the reactor pressure vessel 8 can be adjusted. Furthermore, even when a steam turbine without a fluid coupling is installed and a small RCIC turbine pump integrated with a pump is installed, it is possible to adjust the amount of water injected into the reactor pressure vessel 8 without impairing the conventional reliability. . This small RC
When IC turbine pumps are used, it is possible to reduce the space in the reactor building that houses them, and therefore it is possible to reduce costs.

The third embodiment shown in FIG. 5 will be described below.
As shown in FIG. 5, one of the bypass lines 18 is connected to the discharge pipe 5 between the water injection pump 2 and the reactor pressure vessel 8, and the other is connected to the condensate storage tank 10. As in the first embodiment, the valve opening degree of the bypass line 18 is changed from the discharge pipe 6 side by the reactor water level signal generated from the expansion device 13 and the flow meter 22 for measuring the water level in the reactor pressure vessel 8 as in the first embodiment. Adjustable valve 14 and check valve 15 are installed in bypass line 18. By providing the throttle device 13 with a pressure loss, the pump discharge flow is prevented from being excessively bypassed.

Further, by adjusting the opening of the valve 14 whose valve opening is adjustable by the reactor water level signal, the amount of inflow into the bypass line 18 is adjusted, and a part of the condensate storage tank 1 is adjusted.
Return to 0. Further, the check valve 15 prevents backflow to the bypass line 18. As a result, the amount of water injected into the reactor pressure vessel 8 is adjusted, and the generator 24 can be operated without stopping its rotation. Thus, even when the fluid coupling is not installed or cannot be installed, the amount of water injected into the reactor pressure vessel 8 can be adjusted. Further, even when a steam turbine without a fluid coupling and a small RCIC turbine pump integrated with a pump are used, the amount of water injected into the reactor pressure vessel 8 can be adjusted without deteriorating the conventional reliability. . When this small RCIC turbine pump is used, the space in the reactor building that houses them can be reduced, so that the cost can be reduced.

A fourth embodiment shown in FIG. 6 will be described below.
As shown in FIG. 6, one of the branch lines 21 is connected to the discharge pipe 6 between the injection pump 2 and the reactor pressure vessel 8, and the other is connected to an appropriate place. Suitable places are waste liquid treatment equipment and liquid storage equipment. A flow meter 22 for measuring the water level in the expansion device 13 and the reactor pressure vessel 8 from the discharge pipe 6 side to the branch line 21 in the same manner as in the first embodiment.
The valve 14 and the check valve 15 whose valve opening can be adjusted by the reactor water level signal issued from the reactor are installed.

By giving the pressure loss to the expansion device 13, it is possible to prevent the pump discharge flow from branching excessively. In addition, a valve 14 whose valve opening can be adjusted by a reactor water level signal.
By adjusting the degree of opening, the amount of inflow into the branch line 21 is adjusted. Further, the check valve 15 prevents backflow from the branch line 21 to the discharge pipe 6 side. As a result, the amount of water injected into the reactor pressure vessel 8 is adjusted, and the generator 24 can be operated without stopping its rotation.

As described above, when the fluid coupling is not installed,
Alternatively, even if it cannot be installed, the reactor pressure vessel 8
It is possible to adjust the amount of water injected into the water. Further, even when a steam turbine without a fluid coupling and a small RCIC turbine pump integrated with a pump are used, the amount of water injected into the reactor pressure vessel 8 can be adjusted without deteriorating the conventional reliability. . When this small RCIC turbine pump is used, the space in the reactor building that houses them can be reduced, so that the cost can be reduced.

Next, an example of an operation mode in each embodiment of the present invention will be described. The operation mode of the water injection system during reactor isolation is
There are automatic start mode and system test mode. First, the automatic start mode will be described.

The reactor was isolated from the turbine system, the safety valve was operated, the reactor water level in the reactor pressure vessel 8 dropped, and when the water level became low, and the power supply in the plant was lost for some reason. At that time, the water injection system at the time of reactor isolation automatically starts.

At this time, the valve 20 of the suction pipe 5, the valve 25 of the pipe 3, and the valve 27 of the discharge pipe 6 are opened, and the test line 12 is opened.
Is closed. And the reactor pressure vessel 8
The steam turbine 1 is driven by receiving the steam inside, and the steam turbine 1 starts the water injection pump 2 and the generator 24. The activated water injection pump 2 injects cooling water into the reactor pressure vessel 8, and the activated generator 24 supplies electric power to each device that needs electric power.

In this case, since the reactor water level is lower than the normal water level, the flow meter 22 sends a reactor water level signal corresponding to the low water level to the valve opening adjusting means of the valve 14 and the reactor In response to the water level signal, the valve 14 opens the valve opening to a smaller one of the large opening and the small opening.

In this case, the water in the condensate storage tank 10 is injected into the reactor pressure vessel 8 via the discharge pipe 6 by the injection pump 2. Of the water flowing through the discharge pipe 6 into the reactor pressure vessel, a small flow rate corresponding to the small opening of the valve 14 is diverted to the bypass lines 16, 17, 18 and the branch line 21. However, most of the water is injected into the reactor pressure vessel, and the reactor water level in the reactor pressure vessel rises without hindrance.

In this manner, the water in the condensate storage tank 10 is injected into the reactor pressure vessel 8 by the driving force of the water injection pump 2, and the reactor water level in the reactor pressure vessel 8 rises. Then, when the reactor water level in the reactor pressure vessel 8 rises to the normal water level, the flow meter 22 detects the normal water level. The flowmeter 22 sends a reactor water level signal corresponding to the normal water level of the reactor water level to the valve opening adjusting means of the valve 14, and the valve 14 changes the valve opening between the large opening and the small opening by the reactor water level signal. Open to our large opening.

With this arrangement, of the water injected into the reactor pressure vessel 8 through the discharge pipe 6, a larger amount of water is injected into the bypass lines 16 and 17 than when the valve 14 is set to a small opening. , 18, and the branch line 21. In such a case, the amount of water injected into the reactor pressure vessel 8 decreases, and the rising speed of the reactor water level decreases. Therefore, it takes more time than before in the reactor water level to reach the water level at which the water injection pump 2 must be stopped.
Only during this increased time, the steam turbine 1 of the generator 24
Drive can be extended.

However, finally, when the reactor water level becomes high, the flow meter 22 detects the water level, and the supply of steam to the steam turbine 1 is stopped by the reactor water level signal corresponding to the high water level, and the water is injected. The pump 2 is automatically stopped.

Thereafter, when the water level becomes lower than the normal water level and becomes low again, the supply of steam to the steam turbine 1 is restarted by the reactor water level signal from the flow meter 22 corresponding to the low water level, and the injection pump 2 Automatically restarts and at the same time
Is a large opening. Then, when the flow meter 22 detects that the reactor water level has become the normal water level, the valve opening of the valve 14 is controlled to a large opening.

When such a process is repeated, starting and stopping of devices such as a water injection pump, a steam turbine, and a generator are frequently repeated. However, by extending the time until the reactor water level becomes high, the repetition frequency can be reduced, and the failure and wear of such equipment can be reduced and reliability can be improved.

The water source for water injection into the reactor pressure vessel 8 is the first
The water source is the condensate storage tank water 10, and when the condensate storage tank water runs out, the valve 20 is closed and the valve 19 is opened,
The water source is switched to the suppression pool water 11.

In the description of the automatic start mode, the valve opening of the valve 14 is controlled to a large opening and a small opening by the reactor water level signal. ,
The small opening may be changed to close the valve, and the valve opening of the valve 14 may be controlled to open and close by the reactor water level signal.

Next, the system test mode will be described.
During normal operation of the plant, the reactor water injection equipment is manually started using the steam in the reactor pressure vessel 8, and the condensate storage tank 10 is supplied to the condensate storage tank 10 via the test line 12 which is a test pipe. Perform a system test in the closed loop. At this time, the valve 27 of the discharge pipe 6 is closed, and the valve 26 of the test line 12 is open. If reactor steam is unusable, such as during an installation test, a system test shall be performed using in-house steam.

As described above, in each embodiment of the present invention, the injection pump 2 for injecting water into the reactor pressure vessel 8 is used.
In a reactor water injection facility provided with a water injection pump 2 driven by a steam turbine 1, a reactor pressure vessel 8
The amount of water injected into the reactor pressure vessel 8 is adjusted by adjusting the flow rate flowing through the bypass line 16, 17, 18 or the branch line 21 branched from the discharge pipe 6 between the water injection pump 2 and the water injection pump 2. And the generator 24 can be continuously and continuously operated as long as possible.

[0050]

As described above, according to the present invention,
Since the frequency of starting and stopping the reactor water injection equipment can be reduced and the operation continuation time of the generator can be extended, the power supply and the reliability of the equipment of the reactor water injection equipment can be improved.

[Brief description of the drawings]

FIG. 1 is a system diagram showing a first embodiment of a reactor water injection system of the present invention.

FIG. 2 is a system diagram showing an example of a conventional reactor water injection system.

FIG. 3 is a system diagram showing an example of a conventional reactor water injection system.

FIG. 4 is a system diagram showing a second embodiment of the reactor water injection equipment of the present invention.

FIG. 5 is a system diagram showing a third embodiment of the reactor water injection system of the present invention.

FIG. 6 is a system diagram showing a fourth embodiment of the reactor water injection system of the present invention.

[Explanation of symbols]

1 steam turbine, 2 water injection pump, 5 suction pipe, 6
... Discharge piping, 8 ... Reactor pressure vessel, 10 ... Condensate storage tank, 11 ... Suppression pool, 14 ... Valve, 16,1
7, 18 ... bypass line, 21 ... branch line, 24 ...
Generator.

Claims (4)

[Claims] A steam turbine driven by steam from a reactor pressure vessel; a water injection pump driven by the steam turbine; a discharge pipe for guiding water discharged from the water injection pump into the reactor pressure vessel; A suction pipe that guides water in the suction pump to a suction port of the water injection pump; a generator driven by the steam turbine; a line of pipe that diverts water injection in the discharge pipe; and A flow control device for adjusting a flow rate in the line by a reactor water level signal generated based on a water level in the reactor pressure vessel; 2. The apparatus according to claim 1, wherein the flow rate adjusting device comprises:
A reactor water injection system using a steam turbine driven pump, a valve whose valve opening can be adjusted by a reactor water level signal so that the opening of the valve increases as the water level in the reactor pressure vessel increases. 3. The steam turbine drive according to claim 1 or 2, wherein a throttle device is provided in the line so that the line has a pressure loss and an excessive flow amount is diverted to the line. Nuclear reactor water injection equipment. 4. The reactor water injection facility according to claim 1, 2 or 3, wherein a steam turbine driven pump is provided with a check valve in the line to stop the flow toward the discharge pipe.