A regulator spraying device and a quick control method thereof

Abstract

The present application relates to the field of nuclear power plant operation and automatic control, and particularly relates to a pressurizer spray device and a rapid control method thereof. The device comprises: an emergency boron injection pump, an inlet pipeline of which is connected with a boric acid water tank, an outlet pipeline of which is connected with a spray nozzle of the pressurizer through a spray pipeline, and the outlet pipeline is connected with the boric acid water tank through a first return pipeline and a second return pipeline to form a circulation pipeline, and the outlet pipeline is connected with a primary loop cold section through a boron injection pipeline; an electromagnetic valve is arranged on the first return pipeline, and the electromagnetic valve is provided with pressure logic; an electric valve is arranged on the second return pipeline, and the electric valve is used for regular pump test; an electromagnetic safety valve is further arranged on the outlet pipeline of the emergency boron injection pump, and is used in cooperation with the electromagnetic valve. The method intermittently injects boron into the primary loop by reciprocating opening and closing of the electromagnetic valve with the decrease and increase of the pressure of the primary loop. When the primary loop leaks into the secondary loop during the operation of the nuclear power plant, the emergency boron injection pump is started according to the accident signal, the number of start-stop of the emergency boron injection pump is reduced, the overheat of the motor caused by frequent start-stop of the pump is prevented, the response speed of the emergency spray system is improved, the pressure difference between the primary loop and the secondary loop during the accident is reduced, the leakage amount of the primary loop into the secondary loop is reduced, the radioactive substances are contained, and the accident consequences are reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of nuclear power plant operation and automatic control, in particular to a pressurizer spraying device and a rapid control method thereof. BACKGROUND

[0002] During the operation of the reactor device of a pressurized water reactor nuclear power plant, the primary coolant carries the heat energy released by the nuclear fuel out of the reactor and into the steam generator, and through thousands of heat transfer tubes, the heat is transferred to the secondary water outside the tubes to make the water boil and produce steam; after flowing through the steam generator, the primary coolant is sent into the reactor by the main pump, and this cycle is repeated to continuously carry the heat in the reactor out and convert it into steam.

[0003] When a steam generator heat transfer tube rupture accident occurs, the reactor is shut down, the primary system coolant passes through the steam generator heat transfer tube break and enters the steam generator secondary side, causing the pressure of the primary system to drop, the pressure and water level of the steam generator secondary side to rise, and the radioactive material of the primary system to leak to the secondary side through the steam generator heat transfer tube.

[0004] At this time, the emergency spraying system starts according to the accident signal, sprays high-concentration boric acid solution into the steam space of the pressurizer, quickly reduces the pressure of the primary loop, reduces the pressure difference between the primary / secondary loops, reduces the leakage amount, and at the same time, the reactor device is transferred to a subcritical state.

[0005] According to the leakage amount from the primary loop to the secondary loop and the operation of the primary water supply system, the pressure of the primary loop is within a certain fluctuation range, and when the pressure of the primary system drops to a set value or the liquid level of the pressurizer rises to a set value, the emergency spraying system will automatically shut down. Due to the decay heat of the nuclear fuel after the reactor is shut down for a long time, the temperature and pressure of the primary loop will rise again, and when the pressure of the primary loop rises to a set value, the emergency boron injection pump will be started again to spray into the pressurizer, and the emergency boron injection pump will be shut down after the pressure of the primary loop decreases. Due to the decay heat of the reactor after shutdown, the frequent start and stop of the emergency boron injection pump during the accident process may cause the motor of the pump to overheat and be damaged, resulting in failure of the emergency spraying system and thus inability to control the accident. The emergency boron injection pump needs a period of time from restarting to full load operation, which affects the response speed of the emergency spraying system, the difference between the start pressure set value and the shutdown pressure set value of the emergency spraying system is large, which causes the pressure of the primary system to fluctuate greatly during the accident, and may cause the leakage amount from the primary loop to the secondary loop to increase. SUMMARY

[0006] The technical problem solved by the present application is to provide a stabilizer spraying device and a rapid control method thereof, which can reduce the start-stop times of an emergency boron injection pump during an accident, avoid the possibility of overheating failure of the emergency boron injection pump, improve the response speed of the emergency spraying system, ensure the rapid intervention and exit of the spraying system in the case of an accident, and reduce the amplitude of pressure fluctuation of the primary loop.

[0007] The present application provides a stabilizer spraying device, comprising:

[0008] a boric acid tank,

[0009] an emergency boron injection pump, the inlet pipeline of which is connected with the boric acid tank, the outlet pipeline of which is connected with the spraying nozzle of the stabilizer through a spraying pipeline, and the emergency boron injection pump is connected with the boric acid tank through a first return pipeline and a second return pipeline to form a circulation pipeline, and is connected with a primary loop cold section through a boron injection pipeline;

[0010] An electromagnetic valve is arranged on the first return pipeline, and the electromagnetic valve is provided with pressure logic;

[0011] An electric valve is arranged on the second return pipeline, and the electric valve is used for periodic pump test;

[0012] An electromagnetic safety valve is further arranged on the outlet pipeline of the emergency boron injection pump, and is used in cooperation with the electromagnetic valve;

[0013] The emergency boron injection pump is provided with logic for controlling according to the pressure and liquid level of the stabilizer;

[0014] The stabilizer is connected with a primary loop hot section;

[0015] A spraying electric valve is arranged on the spraying pipeline, and a boron injection electric valve is arranged on the boron injection pipeline.

[0016] In an embodiment of the present application, a throttle orifice plate is further arranged on the second return pipeline.

[0017] In an embodiment of the present application, a pump outlet pressure gauge is arranged on the outlet pipeline of the emergency boron injection pump.

[0018] In an embodiment of the present application, the stabilizer is provided with a liquid level gauge.

[0019] The present application further provides a stabilizer spraying rapid control method, which uses the stabilizer spraying device according to the above technical solution to perform spraying control, comprising:

[0020] When a primary loop to secondary loop leakage accident occurs in a steam generator,

[0021] If the radioactivity in the secondary loop steam pipeline is higher than the alarm value, the primary loop pressure is higher than the first threshold value, and the stabilizer liquid level is lower than the first fixed value, the spray electric valve is automatically opened, the boron injection electric valve is automatically connected to the pipeline, and the electric valve and the electromagnetic valve are closed;

[0022] The emergency boron injection pump extracts boric acid from the boric acid water tank and enters the spray nozzle through the spray electric valve. The boric acid enters the stabilizer steam space, and the stabilizer liquid level begins to rise.

[0023] If the primary loop pressure is lower than the second threshold value, or the stabilizer liquid level is greater than the second fixed value, the electromagnetic valve is opened, the outlet pressure of the emergency boron injection pump is reduced, the spraying to the stabilizer is stopped, and the supercooling degree of the primary loop or the prevention of the overpressure of the primary loop is ensured.

[0024] If the primary loop pressure is higher than the first threshold value, and the stabilizer liquid level is lower than the first fixed value, the electromagnetic valve is closed, and the emergency boron injection pump continues to spray to the stabilizer.

[0025] With the decrease and increase of the primary loop pressure, the opening and closing of the electromagnetic valve are repeated, the boron injection to the primary loop is intermittent, and the primary loop pressure is ensured to be lower than the first threshold value.

[0026] During the opening and closing of the electromagnetic valve, the outlet pressure of the emergency boron injection pump will fluctuate. If the pump outlet pressure table is higher than the fixed value, the pump outlet electromagnetic safety valve is opened to rapidly reduce the pressure.

[0027] When the stabilizer liquid level is higher than the third fixed value, the operation of the emergency boron injection pump is stopped.

[0028] When the reactor fails to be stopped in an emergency, the emergency boron injection pump is started and boron is injected into the loop of the primary loop.

[0029] When the reactor shutdown protection is triggered, the nuclear power of the reactor exceeds the threshold value, the start of the emergency boron injection pump is triggered, the boron injection electric valve is opened, the electromagnetic valve of the first circulation pipeline and the electric valve of the second circulation pipeline are closed, the spray electric valve is closed, and the boron is injected into the primary loop.

[0030] After the boron injection time reaches 120 minutes, the emergency boron injection pump is automatically stopped, or after the emergency boron injection pump start command pulse signal, the emergency boron injection pump is manually stopped to prevent the overpressure of the primary loop.

[0031] In a specific embodiment of the present application, the first threshold value is 8.2 Mpa, the second threshold value is 8 Mpa, the first fixed value is 7.97 m, and the second fixed value is 8.17 m.

[0032] The third fixed value is 8.4 m.

[0033] In a specific embodiment of the present application, when the reactor is normally operated,

[0034] The emergency boron injection pump is in standby state, the electromagnetic valve, the spray electric valve, the boron injection electric valve and the electromagnetic safety valve are all in closed state, and the electric valve is opened.

[0035] In a specific embodiment of the present application, further comprising: when performing a periodic test on the emergency boron injection pump, based on the device state during normal reactor power operation,

[0036] Starting the emergency boron injection pump to run along the second circulating pipeline, verifying each parameter of the emergency boron injection pump;

[0037] If the emergency boron injection pump runs for more than 30 minutes and each parameter is stable, stopping the emergency boron injection pump.

[0038] Compared with the prior art, the pressure stabilizer spraying device and the rapid control method thereof have the following beneficial effects:

[0039] (1) The first circulating loop is provided, when the primary loop pressure is lower than the set value, the electromagnetic valve on the first circulating loop is automatically opened, the emergency boron injection pump is switched to recirculation operation, and the spraying into the steam space of the pressure stabilizer is stopped; when the primary loop pressure is higher than the set value, the electromagnetic valve on the first circulating loop is automatically closed, the emergency boron injection pump starts to spray into the steam space of the pressure stabilizer, and the primary loop system pressure is automatically maintained within the specified range, realizing automatic control of the spraying and reducing the personnel operation burden;

[0040] (2) Due to the addition of the first circulating loop, after the accident signal appears again during the accident, the spraying into the steam space of the pressure stabilizer can be immediately restored by only closing the electromagnetic valve, the response speed of the emergency spraying system is improved, and the response time is shortened from the original 5s to the present 2s;

[0041] (3) Through the opening and closing of the electromagnetic valve, the spraying of the pressure stabilizer can be put into operation and removed, the start and stop of the emergency boron injection pump are avoided, and the damage of the emergency boron injection pump caused by frequent start and stop is avoided;

[0042] (4) The electromagnetic valve is equipped with an electromagnetic safety valve, which can avoid damage of the pump outlet pipeline due to pressure exceeding the design limit during the action of the recirculation pipeline electromagnetic valve of the pump, and improve the reliability of the emergency spraying system;

[0043] (5) The amplitude of the primary loop system pressure fluctuation during the accident is reduced from 0.5Mpa to 0.2Mpa, and the leakage amount of the primary loop system to the secondary loop is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0044] Figure 1 The figure shows the structure of the pressure stabilizer spraying device.

[0045] In the figure,

[0046] 1-boric acid tank, 2-emergency boron injection pump, 3-pump outlet pressure gauge, 4-throttle orifice, 5-electric valve, 6-solenoid valve, 7-solenoid safety valve, 8-spraying electric valve, 9-pressure stabilizer, 10-liquid level gauge, 11-reactor, 12-spraying nozzle, 13-boron injection electric valve, 14-spraying pipeline, 15-boron injection pipeline, 16-primary loop hot section, 17-primary loop cold section, 18-primary loop coolant pump, 19-steam generator. DETAILED DESCRIPTION

[0047] In order to further understand the present application, the embodiments of the present application are described below in conjunction with the examples, but it should be understood that the description is only for further illustrating the features and advantages of the present application, but not for limiting the present application.

[0048] The embodiments of the present application disclose a pressure stabilizer spraying device, as shown in the figure, comprising: Figure 1

[0049] a boric acid tank 1,

[0050] an emergency boron injection pump 2, an inlet pipeline of which is connected with the boric acid tank 1, an outlet pipeline of which is connected with a spraying nozzle 12 of a pressure stabilizer 9 through a spraying pipeline 14, and connected with the boric acid tank 1 through a first backflow pipeline and a second backflow pipeline to form a circulating pipeline, and connected with a primary loop cold section 17 through a boron injection pipeline 15;

[0051] a solenoid valve 6 is arranged on the first backflow pipeline, and the solenoid valve 6 is provided with pressure logic, which immediately terminates the spraying of the pressure stabilizer 9 when the pressure of the primary loop is reduced to a set value;

[0052] an electric valve 5 is arranged on the second backflow pipeline, and the electric valve 5 is used for periodic pump test;

[0053] a throttle orifice 4 is further arranged on the second backflow pipeline, which is used for establishing a pressure head during the periodic pump test;

[0054] a solenoid safety valve 7 is further arranged on the outlet pipeline of the emergency boron injection pump 2, which is used in cooperation with the solenoid valve 6 to prevent the outlet pressure of the emergency boron injection pump 2 from being rapidly increased to cause pipeline overpressure damage when the solenoid valve 6 is rapidly closed.

[0055] a pump outlet pressure gauge 3 is arranged on the outlet pipeline of the emergency boron injection pump 2.

[0056] the emergency boron injection pump 2 is provided with logic for controlling according to the pressure and liquid level of the pressure stabilizer 9;

[0057] the pressure stabilizer 9 is connected with a primary loop hot section 16;

[0058] the pressure stabilizer 9 is provided with a liquid level gauge 10 for monitoring the liquid level in the pressure stabilizer 9. ​

[0059] The spray pipeline 14 is provided with a spray electric valve 8, and the boron injection pipeline 15 is provided with a boron injection electric valve 13.

[0060] The reactor 11 exchanges heat with the steam generator 19 through a primary loop, and the primary loop comprises a primary loop hot section 16 and a primary loop cold section 17.

[0061] When a primary loop to secondary loop leakage accident occurs, the primary loop pressure is rapidly reduced by spraying steam into the steam space of the pressurizer 9, the primary loop to secondary loop pressure difference is reduced, and the leakage amount is reduced;

[0062] The outlet of the emergency boron injection pump 2 is provided with two recirculation pipelines, one of which returns to the boric acid tank 1, and the pipeline is controlled by an electromagnetic valve 6, the electromagnetic valve 6 is provided with a pressure logic, and the electromagnetic valve 6 has the advantages of rapid action, and the pressure of the primary loop system is controlled within a specified range through the on-off of the electromagnetic valve 6; the second recirculation pipeline is controlled by an electric valve 5, and is used for periodically starting the emergency boron injection pump 2 test to verify the performance of the emergency boron injection pump 2;

[0063] The emergency boron injection pump 2 is provided with a logic controlled according to the pressure and liquid level of the pressurizer 9, so that the pressure and liquid level of the pressurizer 9 are controlled within a specified range, and the primary loop pressure is prevented from being too low or overpressure.

[0064] The device of the application can be provided with multiple groups of independent and physically isolated series, and when a series fails, other series can still continue to run and perform their designed functions.

[0065] The embodiment of the application also discloses a pressurizer spraying rapid control method, which sprays and controls by using the pressurizer spraying device in the above technical scheme, and comprises the following steps:

[0066] When a primary loop to secondary loop leakage accident occurs in the steam generator 19,

[0067] If the radioactivity in the secondary loop steam pipeline is higher than an alarm value, the primary loop pressure is higher than a first threshold value, and the liquid level of the pressurizer 9 is lower than a first fixed value, the spray electric valve 8 is automatically opened, the boron injection electric valve 13 is automatically opened, and the electric valve 5 and the electromagnetic valve 6 are closed;

[0068] The first threshold value is 8.2 Mpa, and the first fixed value is 7.97 m;

[0069] The emergency boron injection pump 2 draws boric acid from the boric acid tank 1 and enters the spraying nozzle 12 through the spray electric valve 8, the boric acid enters the steam space of the pressurizer 9, the liquid level of the pressurizer 9 starts to rise, and the pressure in the primary loop starts to drop;

[0070] If the primary loop pressure is lower than the second threshold value, or the pressurizer level is higher than the second fixed value, the electromagnetic valve is opened, the emergency boron injection pump outlet pressure is reduced, the spraying to the pressurizer 9 is stopped, and the supercooling degree of the primary loop is ensured;

[0071] The second threshold value is 8 MPa, and the second fixed value is 8.17 m;

[0072] Due to the decay heat of the reactor 11, the primary loop pressure will slowly rise, if the primary loop pressure is higher than the first threshold value, and the pressurizer 9 level is lower than the first fixed value, the electromagnetic valve 6 is closed, the emergency boron injection pump 2 continues to spray to the pressurizer 9, and the primary loop pressure is reduced;

[0073] With the reduction and increase of the primary loop pressure, the opening and closing of the electromagnetic valve 6 are repeated, the spraying to the steam space of the pressurizer 9 is intermittent, and the primary loop pressure is reduced;

[0074] During the opening and closing of the electromagnetic valve 6, the outlet pressure of the emergency boron injection pump 2 will fluctuate, if the pump outlet pressure gauge 3 is higher than the fixed value, the pump outlet electromagnetic safety valve 7 is opened for rapid pressure reduction;

[0075] When the pressurizer 9 level is too high, that is, the pressurizer 9 level is higher than the third fixed value, to prevent the primary loop water from being overpressured, the emergency boron injection pump 2 is stopped;

[0076] The third fixed value is 8.4 m;

[0077] When the reactor fails to be stopped in an emergency, the emergency boron injection pump 2 is started and boron is injected into the loop of the primary loop, so that the subcriticality of the reactor 11 is ensured;

[0078] When the reactor shutdown protection is triggered, the nuclear power of the reactor 11 exceeds the threshold value, the emergency boron injection pump 2 is triggered to start, the boron injection electric valve 13 is opened, the electromagnetic valve 6 of the first circulation pipeline and the electric valve 5 of the second circulation pipeline are closed, and the spraying electric valve 8 is closed, so that boron is injected into the primary loop;

[0079] After 120 minutes of boron injection, the emergency boron injection pump 2 is automatically stopped, or after 10 minutes of the emergency boron injection pump 2 starting command pulse signal, the emergency boron injection pump 2 is manually stopped, so as to prevent the primary loop from being overpressured.

[0080] The pressurizer spraying rapid control method further comprises the following steps of:

[0081] The emergency boron injection pump 2 is in a standby state, the electromagnetic valve 6, the spraying electric valve 8, the boron injection electric valve 13, and the electromagnetic safety valve 7 are all in a closed state, the electric valve 5 is opened, the coolant in the pressurizer 9 is in a saturated state, the level gauge 10 is in a normal level, the reactor 11 is in power operation, and the primary loop coolant pump 18 is in operation.

[0082] To ensure the availability of the emergency boron injection pump 2 and meet the requirements of the nuclear safety supervision outline, it is necessary to carry out periodic tests on the emergency boron injection pump 2, and when the emergency boron injection pump 2 is tested periodically, it is carried out on the basis of the device state during normal reactor power operation,

[0083] Start the emergency boron injection pump 2 to run along the second circulating pipeline, and verify each parameter of the emergency boron injection pump 2;

[0084] If the emergency boron injection pump 2 runs for more than 30 minutes and each parameter is stable, stop the emergency boron injection pump 2.

[0085] The above description of the embodiments is only used to help understand the method of the present application and its core idea. It should be pointed out that for ordinary skilled in the art, without departing from the principles of the present application, the present application can be improved and modified, and these improvements and modifications also fall within the scope of the claims of the present application.

[0086] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to the embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A pressure stabilizer spray device, characterized in that: include: Boric acid water tank, An emergency boron injection pump, whose inlet pipeline is connected to the boric acid water tank, and whose outlet pipeline is connected to the spray nozzle of the pressure stabilizer through a spray pipeline, is connected to the boric acid water tank through a first return pipeline and a second return pipeline to form a circulation pipeline, and is connected to the primary circuit cold section through a boron injection pipeline; A solenoid valve is provided on the first return line, and the solenoid valve is provided with pressure logic; An electric valve is provided on the second return line, and the electric valve is used for regular pump start-up test; The outlet pipeline of the emergency boron injection pump is also provided with an electromagnetic safety valve, which is used in conjunction with the electromagnetic valve; The emergency boron injection pump is provided with logic for controlling the pressure and liquid level of the pressurizer; The voltage stabilizer is connected to the hot section of the primary circuit; The spray pipeline is provided with a spray electric valve, and the boron injection pipeline is provided with a boron injection electric valve.

2. The pressurizer spraying device according to claim 1, characterized in that: The second return line is also provided with a throttling orifice.

3. The pressurizer spraying device according to claim 1, characterized in that: The outlet pipeline of the emergency boron injection pump is provided with a pump outlet pressure gauge.

4. The pressurizer spraying device according to claim 1, characterized in that: The pressure stabilizer is provided with a liquid level gauge.

5. A method for rapid control of pressure regulator spraying, characterized in that: The method of using the pressurizer spray device according to any one of claims 1 to 4 to perform spray control comprises: When a steam generator leaks from the primary circuit to the secondary circuit, If the radioactivity in the secondary circuit steam pipeline is higher than the alarm value and the primary circuit pressure is higher than the first threshold, and the pressurizer liquid level is lower than the first set value, the spray electric valve will automatically open, the boron injection electric valve will automatically open the pipeline, and the electric valve and solenoid valve will close; The emergency boron injection pump draws boric acid from the boric acid water tank and enters the spray nozzle through the spray electric valve. The boric acid enters the steam space of the pressurizer and the liquid level of the pressurizer begins to rise; If the pressure of the primary circuit is lower than the second threshold, or the liquid level of the pressurizer is greater than the second set value, the solenoid valve is opened to reduce the outlet pressure of the emergency boron injection pump and stop spraying to the pressurizer to ensure the supercooling degree of the primary circuit or prevent the primary circuit from overpressure; If the primary circuit pressure is higher than the first threshold value and the pressurizer liquid level is lower than the first set value, the solenoid valve is closed and the emergency boron injection pump continues to spray to the pressurizer; As the pressure in the primary circuit decreases and increases, the solenoid valve is opened and closed repeatedly, and boron is intermittently injected into the primary circuit to ensure that the pressure in the primary circuit is lower than the first threshold; During the opening and closing process of the solenoid valve, the outlet pressure of the emergency boron injection pump will fluctuate. If the pump outlet pressure gauge is higher than the set value, the electromagnetic safety valve at the pump outlet will open to quickly reduce the pressure. When the liquid level of the pressurizer is higher than the third set value, the emergency boron injection pump is stopped; When an accident occurs in which the reactor fails to be shut down urgently, the emergency boron injection pump starts and injects boron into the loop of the primary circuit; When the reactor shutdown protection is triggered, the nuclear power of the reactor exceeds the threshold, triggering the emergency boron injection pump to start, the boron injection electric valve to open, the solenoid valve of the first circulation pipeline and the electric valve of the second circulation pipeline to close, the spray electric valve to close, and boron to be injected into the primary circuit; After the boron injection time reaches 120 minutes, the emergency boron injection pump will be automatically shut down, or after the emergency boron injection pump start command pulse signal, the emergency boron injection pump will be manually shut down to prevent overpressure in one circuit.

6. The method for rapid control of pressurizer spraying according to claim 5, characterized in that: The first threshold is 8.2Mpa, the second threshold is 8Mpa, the first fixed value is 7.97m, and the second fixed value is 8.17m. The third fixed value is 8.4m.

7. The method for rapid control of pressurizer spraying according to claim 5, characterized in that: Also includes: When the reactor is operating at normal power, The emergency boron injection pump is in a standby state, the solenoid valve, spray electric valve, boron injection electric valve, and electromagnetic safety valve are all in a closed state, and the electric valve is open.

8. The method for rapid spray control of a pressurizer according to claim 7, characterized in that: Also includes: When conducting regular tests on the emergency boron injection pump, the test is conducted based on the device status during normal reactor power operation. Start the emergency boron injection pump and run it along the second circulation pipeline to verify the various parameters of the emergency boron injection pump; If the emergency boron injection pump runs for more than 30 minutes and all parameters are stable, stop the emergency boron injection pump.

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