JP4566982B2 - Nuclear plant and its makeup water equipment - Google Patents

Description

  The present invention relates to a makeup plant for supplying water to a nuclear power plant and facilities therein.

  A nuclear power plant is provided with a makeup water facility for supplying water to the facilities in the plant. The makeup water facility uses a water storage tank as a water source, and supplies water used as makeup water, washing water, sealing water, and the like to each facility in the plant by a makeup water pump.

  One of the facilities where the makeup water facility supplies water is an emergency core cooling facility. The emergency core cooling facility uses the suppression pool (pressure suppression pool) provided near the reactor as the water source, and when the reactor coolant is lost from the core (emergency), the coolant (water) is cooled by the cooling pump. It is equipment to supply to. Generally, there are multiple emergency core cooling facilities in the plant, and each facility is filled with pipes (sealed water supply pipelines) that supply sealed water from the makeup water facility to each emergency core cooling facility. A check valve is provided for holding.

  By the way, there are cases where the makeup water pump is stopped at the time of plant construction testing or periodic inspection. For this reason, water flows backward from the supply destination downstream of the makeup water pump, the inside of the pipe line becomes a vacuum state, and a water hammer phenomenon may occur when the pump is restarted. The technology for suppressing the occurrence of this water hammer phenomenon is a replenishment that is further provided with a check valve on the downstream side of the water supply pump and on the upstream side of the check valve provided in the sealed water supply line of each emergency core cooling facility. There is a water facility (see Patent Document 1).

JP 2000-9886 A

  At the nuclear power plant, in order to confirm that each emergency core cooling facility operates normally in case of an emergency, a periodic inspection (surveillance test) is performed to pump water from the suppression pool with a cooling pump and return it to the suppression pool again. . At this time, since the operating pressure of the cooling pump is higher than the operating pressure of the makeup water pump, water leaks from the check valve provided in the sealed water supply pipe of each emergency core cooling facility and flows toward the makeup water facility. May flow backwards.

  If a reverse flow of the emergency core cooling facility as described above occurs in a plant where a check valve is provided upstream of the sealed water supply line, including plants to which the above technology is applied, Leaked water may lose its escape due to the action of the valve, and the pipeline of the makeup water facility may be pressurized. In this case, leaked water enters the other emergency core cooling facility from the pressurized supplemental water facility pipe, and the pressure relief valve provided in the emergency core cooling facility eliminates the pressure abnormality. However, it is recognized as an abnormality in the emergency core cooling facility and an alarm is issued.

  Therefore, when a backflow of sealed water occurs as described above, it is necessary to confirm that there is no abnormality even if the emergency core cooling facility is operating normally, and there is room for improvement in terms of plant operation. is there. In the unlikely event that an emergency occurs during the checking operation, there is a problem that the core cannot be cooled even though it is operating normally.

  An object of the present invention is to provide a nuclear power plant capable of proper plant operation and its makeup water equipment.

  (1) In order to achieve the above object, the present invention provides a replenishing water pump that pumps water in a water storage tank to a replenishing water pipeline, and a reverse flow of water that is provided in the replenishing water conduit and is pumped by the replenishing water pump. A first check valve for preventing the accident, and an emergency core cooling facility that is provided on the downstream side of the first check valve from the supply water pipe and supplies water to the reactor core in an emergency. A connected sealed water supply line, a second check valve provided in the sealed water supply line and preventing water from flowing from the emergency core cooling facility to the makeup water line, 1 provided on the downstream side of the one check valve, and pressure control means for holding the pressure in the makeup water pipe line within a set value.

  (2) The pressure control means in (1) is preferably a pressure relief valve.

  (3) Preferably, the pressure control means in the above (1) is a bypass line provided with an orifice and having both ends connected to the makeup water line so as to bypass the first check valve. Shall.

  (4) Preferably, the pressure control means in the above (1) is a bypass pipe provided with a flow rate control valve and connected at both ends to the makeup water pipe so as to bypass the first check valve. It shall be.

  (5) The above (4) is preferably a control device that opens the flow control valve to a predetermined opening at the start of a periodic inspection of the emergency core cooling facility and closes the flow control valve at the end of the periodic inspection. Shall be provided.

  (6) The pressure control means in (1) is preferably an on-off valve provided on the upstream side of the second check valve on the sealed water supply pipe, and the on-off valve and the second on-off valve. It is assumed that the accumulator is provided between the check valves.

  (7) In the above (6), preferably, the detection value is attached to the accumulator and detects the pressure in the internal gas region, and the detection value is determined according to the detection value input from the pressure detection unit. A replenishing water facility for a nuclear power plant, comprising: a control device that opens the on-off valve when it becomes smaller than a set value and closes the on-off valve when the detected value reaches the set value.

  (8) In order to achieve the above object, the present invention provides a nuclear reactor, an emergency core cooling facility for supplying water to the core of the nuclear reactor in an emergency, and a replenishment for pumping water from a water storage tank to a supplementary water pipe A water pump, a first check valve provided in the make-up water pipe and preventing a backflow of water pumped by the make-up water pump, and a downstream of the first check valve from the make-up water pipe A sealed water supply pipe that is provided in a branched manner and connected to the emergency core cooling facility, and is provided in the sealed water supply pipeline, and water flows from the emergency core cooling facility to the makeup water pipeline. And a pressure control means that is provided on the downstream side of the first check valve and holds the pressure in the makeup water conduit within a set value.

  According to the present invention, since proper plant operation can be performed, the reliability and safety of a nuclear power plant can be improved.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic system diagram of a nuclear power plant according to a first embodiment of the present invention.

  The nuclear power plant shown in this figure includes a nuclear reactor containment vessel 1, a makeup water supply facility 2 that supplies water to the facilities in the plant, and a reactor core in an emergency when reactor coolant is lost from the core of a reactor 10 (described later). Are mainly equipped with emergency core cooling facilities 3A and 3B for supplying coolant to the main body.

  In the reactor containment vessel 1, a reactor (reactor pressure vessel) 10 and a suppression pool (pressure suppression pool) 11 provided below the reactor 10 are provided.

  Steam generated in the nuclear reactor 10 is used as a working fluid for rotating a turbine (not shown) that drives a generator, or as a heat source for generating a working fluid. In addition, water is stored in the suppression pool 11 as a reactor coolant.

  The makeup water supply facility 2 is provided in a storage tank (condensate storage tank) 21 that is a water source of the facility 2, a makeup water conduit 22a connected to the reservoir 21, and a makeup water conduit 22a. A replenishment water pump 23 for pumping water of water, a check valve 24 provided in the replenishment water conduit 22a to prevent the water in the replenishment water conduit 22a from flowing back to the water storage tank 21, and a replenishment water conduit 22a. The replenishment water conduits 22b and 22c for connecting the replenishment water conduit 22a and the equipment requiring water, and the replenishment water conduit 22d connected to the replenishment water conduit 22a and connecting the replenishment water conduit 22a and the emergency core cooling facilities 3A and 3B. A check valve 25 provided in the make-up water line 22d and preventing the water in the make-up water line 22d from flowing back toward the make-up water line 22a, and a make-up water line 22d. Emergency core cooling facility 3A Non-return check that is provided in the sealed water supply pipes 26a and 26b connecting the 3B and the sealed water supply pipes 26a and 26b and prevents water from flowing from the emergency core cooling facilities 3A and 3B to the makeup water pipe 22d. Valves 27a and 27b and a relief valve (pressure relief valve) 28 provided in the makeup water conduit 22d and holding the pressure in the makeup water pipeline 22d within a set value are provided.

  To the makeup water pipe 22a, along the flow direction (downstream side) of the water discharged from the makeup water pump 23, a connection section 29a to which the makeup water pump 23, the check valve 24 and the makeup water pipe 22b are connected, a makeup water pipe A connecting portion 29b to which the paths 22c and 22d are connected is provided in order.

  The make-up water pump 23 sucks the water in the water tank 1, and supplies make-up water, washing water, and other facilities to the water supply destinations including the emergency core cooling facilities 3A and 3B through the make-up water pipelines 22a to 22d. Supplying sealed water.

  The check valve 24 prevents the water in the makeup water conduit 22 a from flowing back into the water storage tank 21 when the makeup water pump 23 is stopped.

  The makeup water pipelines 22b and 22c are connected to a turbine building and a waste treatment building in the plant, and supply water to equipment (for example, a condenser or the like) installed in these buildings.

  A connecting portion 29c, to which a check valve 25 and a sealed water supply line 26a are connected, are connected to the makeup water pipe 22d toward the flow direction (downstream side) of the water discharged from the makeup water pump 23, and the sealed water supply line. A connecting portion 29d to which 26b is connected is provided in order. Further downstream of the connecting portion 29d, other equipment (for example, a pool (not shown) provided on the top floor of the reactor building) in the reactor building (not shown) in which the reactor containment vessel 1 is installed. Etc.) are connected.

  The check valve 25 is installed on the downstream side of the connection portion 29 b and the upstream side of the connection portion 29 c, and is installed at a location lower than the water level of the water storage tank 1. By the way, if there is a supply destination of makeup water installed at a position higher than the water level of the water storage tank 1 on the downstream side of the makeup water pump 23, the makeup water pump 23 is turned off at the time of tests or periodic inspections during the construction of the nuclear power plant. When the water supply is stopped, a drop in water may occur from the supply water supply destination equipment due to a relative height difference from the water level of the water storage tank 1. The check valve 25 prevents the occurrence of such a water drop (back flow) and suppresses the occurrence of a water hammer phenomenon on the downstream side when the makeup water pump 23 is restarted, thereby reducing the pipe line. Protects from damage.

  The relief valve 28 is provided on the makeup water conduit 22d so as to be located downstream of the check valve 25. The relief valve 28 automatically opens when the pressure in the make-up water pipe 22d increases and reaches a preset set value, and closes again when the pressure drops from the set value. It is like that. As a result, the relief valve 28 keeps the pressure in the makeup water pipe 22d within the set value. The set value for opening the valve body is set lower than the set value for opening relief valves 38a and 38b (described later) in the emergency core cooling facilities 3A and 3B.

  The sealed water supply line 26a is connected to the emergency core cooling facility 3A on the downstream side, and the sealed water supply line 26b is connected to the emergency core cooling facility 3B on the downstream side. The makeup water facility 2 supplies water to the emergency core cooling facilities 3A and 3B via the sealed water supply pipelines 26a and 26b, and the pipelines in the emergency core cooling facilities 3A and 3B are always kept full. is doing.

  The check valve 27a is provided in the sealed water supply pipeline 26a, and the check valve 27b is provided in the sealed water supply pipeline 26b. The check valves 27a and 27b are provided so as to circulate water in the direction of the emergency core cooling equipment 3A and 3B from the supply water pipeline 22d. On the contrary, the check valves 27a and 27b are supplied from the emergency core cooling equipment 3A and 3B. It is provided so that water does not flow in the direction of the water pipeline 22d.

  The emergency core cooling facility 3A includes a cooling pipe 31a connected to the suppression pool 11, a cooling pump 32a that is provided in the cooling pipe 31a and pumps water in the suppression pool 11, and a cooling pipe in the connection portion 33a. 31a, a cooling line 34a connected to the reactor 10 on the opposite side of the connection part 33a, a valve 35a provided in the cooling line 34a, and a connection part 33a connected to the cooling line 31a and connected. The cooling line 36a connected to the suppression pool 11 on the opposite side of the portion 33a, the valve 37a provided in the cooling line 36a, the cooling line 31a, and the cooling line 36a are provided so as to bypass the equipment 3A. There is provided a relief valve (pressure relief valve) 38a for keeping the pressure in the inner pipes 31a, 34a, 36a within a set value.

  The operating pressure of the cooling pump 32a is set higher than the pressure of the sealed water supplied from the makeup water supply facility 2 through the sealed water supply pipe 26a. Thus, when the cooling pump 32a is in operation, water is not circulated from the makeup water supply facility 2 to the emergency core cooling facility 3A via the sealed water supply pipeline 26a.

  The relief valve 38a has the same configuration as the relief valve 28 of the makeup water facility 2 described above, and keeps the pressure in the cooling pipe 31a within a set value. The set value for opening the valve body of the relief valve 38a is set higher than the set value for opening the relief valve 28. When the pressure in the cooling pipe line 31a reaches the set value, the relief valve 38a allows water to escape to the downstream side of the valve 37a of the cooling pipe line 36a and keeps the pressure within a predetermined value.

  The emergency core cooling facility 3A opens the valve 35a and closes the valve 37a when the reactor coolant is lost from the core due to a pipe break in the reactor cooling system in the reactor 10 (in an emergency). In this state, the water in the suppression pool 11 is immediately supplied to the reactor core by the cooling pump 32a and cooled. The emergency core cooling facility 3A during normal operation closes both the valves 35a and 37a and stops its function, but in order to check whether the facility 3A operates normally in preparation for an emergency as described above. Inspection (surveillance test) needs to be performed regularly.

  In the surveillance test, water that has been pressurized by the cooling pump 32a using the suppression pool 11 as a water source with the valve 35a opened and the valve 37a closed is again supplied to the suppression pool 11 through the cooling pipelines 31a and 36a. Check the operating status of the feed and cooling pump 31a.

  Since the emergency core cooling facility 3B has the same configuration as the emergency core cooling facility 3A described above, the description thereof will be omitted, and the symbol “a” attached to each configuration will be replaced with “b” and the following description will be given as appropriate. I will use it.

  In the nuclear power plant configured as described above, when a surveillance test is performed in the emergency core cooling facility 3B, the operating pressure of the cooling pump 32b is higher than the pressure of the sealed water in the sealed water supply line 26b. In some cases, water leaks to the side of the makeup water pipe 22d through the check valve 27b.

  When leakage occurs in the check valve 27b in this way, the leakage water from the emergency core cooling facility 3B loses escape due to the action of the check valve 25 and pressurizes the replenishing water line 22d. When the pressure in the makeup water conduit 22d increases and reaches the set value of the relief valve 28, the valve body of the relief valve 28 is opened to lower the pressure in the makeup water pipeline 22d. When the pressure in the replenishing water line 22d becomes smaller than the set value by letting water escape by the relief valve 28, the relieving valve 28 closes the valve body again to keep the pressure in the refilling water line 22d within the set value.

  At this time, since the set value of the relief valve 28 is set lower than the set value of the relief valves 38a and 38b in the emergency core cooling facilities 3A and 3B, these valves 38a and 38b are opened to cause pressure abnormality. There is no cancellation. Thus, according to the present embodiment, even if a pressure abnormality occurs in the makeup water conduit 22d due to leakage in the check valve 27b, it can be solved without affecting other facilities.

  Here, in order to facilitate understanding of the effects of the present embodiment, a comparative example of the present embodiment will be described with reference to the drawings.

  FIG. 2 is a schematic system diagram of a nuclear power plant that is a comparative example of the first embodiment of the present invention. The same parts as those in the previous figure are denoted by the same reference numerals and the description thereof will be omitted (the latter figure will be treated similarly).

  The nuclear power plant shown in this figure includes a makeup water supply facility 102 different from the makeup water supply facility 2 of the above embodiment. This makeup water supply facility 102 is different from the makeup water supply facility 2 described above in that it has a makeup water pipe 122 d provided with no relief valve 28.

  In the nuclear power plant of the comparative example configured as described above, when the check valve 27b is leaked by the surveillance test in the emergency core cooling facility 3B, the makeup water pipe 122d is added by the leaked water as in the above embodiment. Pressed. However, in this case, the pressurization due to the leaked water is propagated from the replenishing water pipe 122d to the emergency core cooling equipment 3A via the sealed water supply pipe 26a, and the pressure in the emergency core cooling equipment 3A is also increased.

  As a result, when the pressure in the emergency core cooling facility 3A reaches the set value of the relief valve 38a, the valve body of the relief valve 38a is opened to reduce the pressure in the emergency core cooling facility 3A and the supplementary water conduit 22d. . When the pressure in the emergency core cooling facility 3A and the make-up water conduit 22d becomes smaller than the set value by letting water escape by the relief valve 38a, the relief valve 38a closes the valve body again to keep the pressure within the set value.

  Also in such a comparative example, the pressure abnormality due to the leaked water accompanying the surveillance test is solved by the relief valve 38a, but at the same time, an alarm that the pressure abnormality has occurred in the emergency core cooling facility 3A is issued. . Therefore, when the backflow of leaked water as described above occurs, even if the emergency core cooling facility 3A is operating normally, it is necessary to confirm that there is no abnormality, which improves the operation of the plant. There was room. In addition, in the unlikely event that an emergency occurs during the checking operation, the fact that the core cannot be cooled despite the fact that the emergency core cooling facility 3A is operating normally was also a problem to be improved.

  On the other hand, the present embodiment is a pressure control means that is provided on the make-up water pipe 22d so as to be positioned downstream of the check valve 25 and holds the pressure in the make-up water pipe 22d within a set value. A relief valve 28 is provided. Even if water leaks through the check valve 27b and the inside of the supplementary water line 22d is pressurized during the surveillance test of the emergency core cooling facility 3B, the relief valve 28 releases the pressure in the supplementary water pipe 22d. It can be held within 28 set values.

  That is, according to the present embodiment, even if the pressure in the makeup water pipe 22d rises, the pressure control means (relief valve 38a) provided in the other equipment (emergency core cooling equipment 3A) as in the comparative example. ) Can properly operate the plant without eliminating the pressure abnormality. Therefore, according to the present embodiment, since proper plant operation can be performed, the reliability and safety of the nuclear power plant can be improved.

Next, a second embodiment of the present invention will be described.
The present embodiment is different from the first embodiment in that a bypass conduit provided with an orifice is provided as pressure control means for the makeup water conduit 22d.

  FIG. 3 is a schematic system diagram of a nuclear power plant according to the second embodiment of the present invention.

  The nuclear power plant shown in this figure includes a makeup water supply facility 202 that is different from the makeup water supply facility 2 of the first embodiment, and the other parts are the same as those of the first embodiment.

  The makeup water supply facility 202 includes a bypass conduit 50 having both ends connected to the makeup water conduit 22 d so as to bypass the check valve 25. The bypass pipe 50 is provided with an orifice 51 having a reduced pipe diameter. The upstream end portion of the bypass pipe 50 is connected to the downstream side of the connection portion 29b and the upstream side of the check valve 25, and the downstream end portion opposite thereto is connected to the downstream side of the check valve 25 and the connection portion. It is connected to the upstream side of the portion 29c. The other parts are the same as the makeup water supply facility 2.

  The diameter of the orifice 51 is determined in consideration of the amount of water leaking through the check valves 27a and 27b when the surveillance test is performed in the emergency core cooling facilities 3A and 3B, and at least the makeup water pump 23 is set after the surveillance test. When restarting, set so that the water hammer phenomenon does not occur downstream. Further, the diameter of the orifice 51 is preferably set so that the same amount of water that leaks per unit time through the check valves 27a and 27b escapes to the upstream side (connecting portion 29b side). .

  According to the makeup water supply facility 202 provided with such a bypass pipe 50, even if leakage water from the check valve 27b occurs, it can be released to the upstream side (connecting portion 29b side) of the check valve 25. Therefore, the pressurization of the makeup water conduit 22d can be eliminated without propagating to other equipment. Therefore, the present embodiment can provide the same effects as those of the first embodiment.

Next, a third embodiment of the present invention will be described.
The present embodiment is different from the second embodiment in that a bypass conduit provided with a flow rate control valve is provided as pressure control means for the makeup water conduit 22d.

  FIG. 4 is a schematic system diagram of a nuclear power plant according to the third embodiment of the present invention.

  The nuclear power plant shown in this figure includes a makeup water supply facility 302 different from the makeup water supply facility 202 of the second embodiment, and a control device 304 that controls the makeup water supply facility 302. The part is the same as in the first embodiment.

  The makeup water supply facility 302 includes a bypass pipeline 60 having both ends connected to the makeup water pipeline 22d so as to bypass the check valve 25. The upstream end portion of the bypass pipe 60 is connected to the downstream side of the connection portion 29b and the upstream side of the check valve 25, and the opposite downstream end portion is connected to the downstream side of the check valve 25 and the connection portion. It is connected to the upstream side of the portion 29c. The other parts are the same as the makeup water supply facility 2.

  The bypass pipe 60 is provided with a flow control valve 61 that controls the flow of water in the pipe 60. The flow control valve 61 is connected to the control device 304, and is appropriately opened and closed with a predetermined opening by an output signal from the control device 304. In this embodiment, an air operated valve is used as the flow control valve 61.

  The control device 304 controls the timing for opening the flow control valve 61 and the opening degree at that time. One method of controlling the flow control valve 61 is to open the flow control valve 61 to a predetermined opening at the start of the surveillance test (periodic inspection) of the emergency core cooling facility 3B, and to close the flow control valve 61 at the end of the surveillance test. There is something that closes. In this case, the valve opening is set in accordance with the amount of water leaking through the check valve 27b and the water hammer phenomenon, as in the case of setting the diameter of the orifice 51 in the second embodiment. It should be done in consideration. The start and end of the surveillance test may be determined from the open / closed state of the valve 37b. That is, if the valve 37b is in an open state, it can be determined that the surveillance test has started, and in the opposite case, it can be determined that the operation has ended (or during normal operation). When the operation mode for the surveillance test is set in the control device 304 in advance, the flow control valve 61 may be set to open while the mode is selected.

  Even in the nuclear power plant configured as described above, even if leakage water from the check valve 27b is generated, it can be released to the upstream side of the check valve 25, so that the pressurization of the makeup water pipe 22d is transmitted to other equipment. It can be solved without letting Therefore, the present embodiment can provide the same effects as those of the second embodiment.

  As another control method, a pressure sensor (not shown) is attached to the makeup water pipe 22d so that the detected pressure value is input to the control device 304, and the pressure detection input from the pressure sensor is performed. A method of determining the opening degree and opening / closing timing of the flow control valve 61 according to the value may be used. By controlling in this way, it is possible to detect an increase in pressure in the makeup water conduit 22d, so that it is possible to objectively determine that water has leaked through the check valve, and the amount of leakage It is possible to perform optimal control according to the conditions.

Next, a fourth embodiment of the present invention will be described.
This embodiment is different from the first embodiment in that a sealed water supply pipe provided with an on-off valve and an accumulator is provided as pressure control means for the makeup water pipe 22d.

  FIG. 5 is a schematic system diagram of a nuclear power plant according to the fourth embodiment of the present invention.

  The nuclear power plant shown in this figure includes a makeup water supply facility 402 different from the makeup water supply facility 2 of the first embodiment, and a control device 404 that controls the makeup water supply facility 402. The part is the same as in the first embodiment.

  The make-up water supply facility 402 includes on / off valves 70a and 70b provided on the sealed water supply pipes 26a and 26b so as to be located upstream of the check valves 27a and 27b, and the on-off valves 70a and 70b and the check valves. The accumulators 71 a and 71 b provided between 27 a and 27 b are provided, and the other parts are the same as the makeup water supply facility 2.

  The accumulators 71a and 71b have gas regions inside. The water flowing through the sealed water supply pipes 26a and 26b is introduced into the accumulators 71a and 71b according to the pressure in the pipes 26a and 26b, and compresses the gas region.

  Pressure sensors 72a and 72b for detecting pressure values in the gas region are attached to the accumulators 71a and 71b. The pressure sensors 72a and 72b are connected to the control device 404, detect the pressure in the gas region in the accumulators 71a and 71b, and output it to the control device 404.

  The on-off valves 70a and 70b are connected to the control device 404, and are opened and closed by an output signal from the control device 404 that is output according to the pressure value of the gas region in the accumulators 71a and 71b. In the present embodiment, electric valves driven by electricity are used as the on-off valves 70a and 70b.

  The control device 404 outputs a signal for opening the valve body to the on-off valve 70a (70b) when the detected value input from the pressure sensor 72a (72b) becomes smaller than the set value, and when the detected value reaches the set value, the valve body. A signal to close is output. The set value used to open and close the valve body is the pressure acting on the gas region in the accumulator 71a (71b) in a state where the sealed water is fully held in the pipe line in the emergency core cooling facility 3A (3B). Set based on pressurization due to leaked water generated during the surveillance test. With this setting, even if the sealed water in the emergency core cooling facility 3A (3B) is reduced, the sealed water is appropriately controlled from the make-up water supply facility 402 each time. The pipe line of the core cooling facility 3A (3B) can be always kept full of water.

  In the nuclear power plant configured in this way, when the pressure in the gas region of the accumulators 71a and 71b is maintained at a set value or higher, the on-off valves 70a and 70b are closed regardless of whether during normal operation or during a surveillance test. Thus, the emergency core cooling facilities 3A and 3B and the makeup water supply facility 402 are isolated. At this time, when a surveillance test is performed in the emergency core cooling facility 3B, even if a leak occurs in the check valve 27b and water enters the on-off valve 70b side, the leaked water compresses the gas region in the accumulator 71b. However, since it is guided into the accumulator 71b, the pressure rise is alleviated.

  As described above, according to the present embodiment, even if leakage water is generated, the emergency core cooling facilities 3A, 3B and the makeup water supply facility 204 are isolated by the on-off valves 70a, 70b, so that pressure is applied to other facilities. It is possible to operate the plant properly without propagating. Therefore, according to the present embodiment, as in each of the above-described embodiments, an appropriate plant operation can be performed, so that the reliability and safety of the nuclear power plant can be improved.

  Further, when the pressure value in the gas region of the accumulator 71b (71a) becomes smaller than the set value, the control device 404 in the nuclear power plant according to the present embodiment seals the water in the pipeline of the emergency core cooling facility 3B (3A). Can be determined to be insufficient, and the on-off valve 70b (70a) can be opened to keep the water full again. As described above, according to the present embodiment, even if the sealed water in the emergency core cooling facility 3B (3A) is insufficient, it can be automatically replenished. Can be more effectively suppressed.

  In the description of each of the above-described embodiments, only the case where the surveillance test is performed in the emergency core cooling facility 3B is described in a simplified manner. However, in the case where the surveillance test is performed in the emergency core cooling facility 3A. Needless to say, the same effect can be obtained. Further, in the description of each of the above embodiments, the case where there are two emergency core cooling facilities is taken as an example for the sake of simplicity, but the present invention can be similarly applied to the case where there are three or more.

  In the above description, the pressure increase generated in the makeup water pipe 22d is caused by the check valve 25 having a function of suppressing the occurrence of the water hammer phenomenon. In addition to this, the emergency core cooling facilities 3A, 3B The present invention is also applicable to the case where a check valve for other uses (for example, the check valve 24 in FIG. 1) is provided on the upstream side of the inside, or when a flow suppression means other than the check valve is provided. Can be applied. This is because if the means for losing the leakage water is provided on the upstream side of the emergency core cooling facility, a pressure increase in the makeup water pipe can occur.

1 is a schematic system diagram of a nuclear power plant according to a first embodiment of the present invention. The schematic system diagram of the nuclear power plant which is a comparative example of the 1st Embodiment of this invention. The schematic system diagram of the nuclear power plant which is the 2nd Embodiment of this invention. The schematic system diagram of the nuclear power plant which is the 3rd Embodiment of this invention. The schematic system diagram of the nuclear power plant which is the 4th Embodiment of this invention.

Explanation of symbols

2 Supply Water Supply Facility 3 Emergency Core Cooling Facility 10 Reactor 21 Reservoir 22 Supply Water Pipe Line 23 Supply Water Pump 25 Check Valve 26 Sealed Water Supply Line 27 Check Valve 28 Relief Valve 50 Bypass Line 51 Orifice 60 Bypass line 61 Flow control valve 70 On-off valve 71 Accumulator 72 Pressure sensor 202 Makeup water supply facility 302 Makeup water supply facility 304 Controller 402 Makeup water supply facility 404 Control device

Claims (8)

A makeup water pump that pumps the water in the reservoir to the makeup water line;
A first check valve provided in the make-up water line and preventing a back flow of water pumped by the make-up water pump;
A sealed water supply line that is provided on the downstream side of the first check valve and is branched from the makeup water line and connected to an emergency core cooling facility that supplies water to the reactor core in an emergency;
A second check valve that is provided in the sealed water supply pipe and prevents water from flowing from the emergency core cooling facility to the makeup water pipe;
A supplementary water facility for a nuclear power plant, comprising pressure control means provided downstream of the first check valve and maintaining the pressure in the supplementary water pipeline within a set value. The makeup water equipment for a nuclear power plant according to claim 1,
A makeup water facility for a nuclear power plant, wherein the pressure control means is a pressure relief valve. The makeup water equipment for a nuclear power plant according to claim 1,
The water supply facility for a nuclear power plant, wherein the pressure control means is a bypass pipe provided with an orifice and having both ends connected to the water supply pipe so as to bypass the first check valve . The makeup water equipment for a nuclear power plant according to claim 1,
The nuclear power plant supplementary water, wherein the pressure control means is a bypass conduit provided with a flow rate control valve and having both ends connected to the supplementary water conduit so as to bypass the first check valve. Facility. In the makeup water facility for a nuclear power plant according to claim 4,
A supplementary water facility for a nuclear power plant comprising a control device that opens the flow control valve to a predetermined opening at the start of a periodic inspection of the emergency core cooling facility and closes the flow control valve at the end of the periodic inspection. . The makeup water equipment for a nuclear power plant according to claim 1,
The pressure control means is an open / close valve provided on the upstream side of the second check valve on the sealed water supply pipe, and an accumulator provided between the open / close valve and the second check valve. A replenishment water facility for a nuclear power plant characterized by being. The makeup water equipment for a nuclear power plant according to claim 6,
A pressure detecting means attached to the accumulator for detecting the pressure of the gas region inside;
A control device that opens the on-off valve when the detection value becomes smaller than a set value according to the detection value input from the pressure detection means, and closes the on-off valve when the detection value reaches the set value. A supplementary water facility for nuclear power plants. A nuclear reactor,
An emergency core cooling facility for supplying water to the reactor core in an emergency,
A makeup water pump that pumps the water in the reservoir to the makeup water line;
A first check valve that is provided in the makeup water pipe and prevents a back flow of water pumped by the makeup water pump;
A sealed water supply line that is provided on the downstream side of the first check valve and is branched from the makeup water line and connected to the emergency core cooling facility;
A second check valve which is provided in the sealed water supply pipe and prevents water from flowing from the emergency core cooling facility to the makeup water pipe;
A nuclear power plant comprising pressure control means provided downstream of the first check valve and holding the pressure in the makeup water pipe line within a set value.

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