A method and system for purging a head tank of a boron recovery system prior to a nuclear power plant outage

Abstract

The present application relates to a kind of nuclear power plant overhaul before boron recovery system head tank purging method and system, comprising the following steps: step S1.water is filled to TEP head tank, and the water volume in TEP head tank is monitored;Step S2.judge whether the water volume in TEP head tank reaches preset value, if yes, step S3 is executed, if no, continue to fill water to TEP head tank;Step S3.stop filling water, nitrogen is filled into TEP head tank, and the real-time pressure of TEP head tank is monitored in real time;Step S4.judge whether the real-time pressure of TEP head tank reaches set pressure, if yes, step S5 is executed, if no, continue to fill gas to TEP head tank;Step S5.open pressure relief valve, and the real-time pressure of TEP head tank is monitored;Step S6.judge whether the real-time pressure in TEP head tank drops to pressure threshold, if no, continue to monitor;If yes, return to step S3, repeat preset time step S3 to step S6 is executed.The present application can greatly reduce the work critical path time, improve work efficiency, reduce work risk, save production cost.

Description

Technical Field

[0001] The present invention relates to the technical field of nuclear power overhaul, and more particularly to a method and system for purging a header box of a boron recovery system before overhaul of a nuclear power plant. Background Art

[0002] Three days before the nuclear power overhaul, the unit needs to perform TEP (boron recovery system) head box purge to reduce its hydrogen content and prepare for subsequent hydrogen and oxygen separation.

[0003] Due to the characteristics of the pressure reducing valve, the existing TEP header box purge is very fast when the header box pressure is low, and it becomes slower and slower as the header box pressure rises. Historical data and overhaul procedures indicate that one charging cycle takes 2.5 hours. Therefore, including the pressure holding and exhaust time, one purge takes 3 hours, and five purges take 18 hours, which is extremely time-consuming and seriously occupies the overhaul path. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a method and system for purging the head box of a boron recovery system before overhaul of a nuclear power plant in response to the problems existing in the prior art.

[0005] The technical solution adopted by the present invention to solve the technical problem is to construct a head box purging method of a boron recovery system before overhaul of a nuclear power plant, comprising the following steps:

[0006] Step S1. Filling the TEP header tank with water and monitoring the water volume in the TEP header tank in real time during the filling process;

[0007] Step S2. Determine whether the water volume in the TEP header tank reaches a preset value. If so, execute step S3; if not, continue to fill the TEP header tank with water;

[0008] Step S3. Stop filling water, fill nitrogen into the TEP header box, and monitor the real-time pressure of the TEP header box in real time during the filling process;

[0009] Step S4. Determine whether the real-time pressure of the TEP header box reaches the set pressure. If so, execute step S5; if not, continue to inflate the TEP header box;

[0010] Step S5. Open the pressure relief valve and monitor the real-time pressure of the TEP header tank after opening the pressure relief valve;

[0011] Step S6. Determine whether the real-time pressure in the TEP header box drops to the pressure threshold. If not, continue to monitor the real-time pressure in the TEP header box; if so, return to step S3 and repeat steps S3 to S6 for a preset number of times.

[0012] In the method for purging the head box of the boron recovery system before overhaul of a nuclear power plant described in the present invention, the preset value is 70m 3 , the set pressure is 2.5 bar.a, and the pressure threshold is 1.15 bar.a.

[0013] In the method for purging the header box of a boron recovery system before overhaul of a nuclear power plant according to the present invention, step S1 comprises:

[0014] The water filling control receives a water filling instruction;

[0015] The water filling control outputs a water filling trigger signal according to the water filling instruction;

[0016] The water filling valve opens according to the water filling trigger signal and fills water into the TEP header tank;

[0017] During the water filling process of the TEP header box, the water level monitoring module monitors the real-time water level information in the TEP header box in real time;

[0018] The water volume in the TEP header tank is monitored based on the real-time water level information.

[0019] In the method for purging the header box of a boron recovery system before overhaul of a nuclear power plant according to the present invention, step S3 comprises:

[0020] The control unit outputs a water filling stop control signal;

[0021] The water filling valve is closed according to the stop water filling control signal to stop filling water into the TEP header tank;

[0022] The control unit outputs a charging start signal;

[0023] The charging valve is activated according to the charging start signal and fills nitrogen into the TEP head box;

[0024] During the inflation process, the pressure monitoring module monitors the real-time pressure of the TEP head box in real time and outputs real-time pressure data.

[0025] In the method for purging the header box of a boron recovery system before overhaul of a nuclear power plant described in the present invention, during the inflation process, the valve of the inflation valve is adjusted to 2 barg.

[0026] In the method for purging the header box of a boron recovery system before overhaul of a nuclear power plant according to the present invention, step S4 comprises:

[0027] The control unit compares the real-time pressure data of the TEP head box with the set pressure. If the set pressure is reached, the control unit outputs a stop inflation control signal and a pressure relief start signal. If the set pressure is not reached, the control unit does not output a stop inflation control signal.

[0028] In the method for purging the header box of a boron recovery system before overhaul of a nuclear power plant according to the present invention, step S5 comprises:

[0029] The pressure relief valve receives a pressure relief opening signal and starts pressure relief according to the pressure relief opening signal;

[0030] During the pressure relief process, the pressure monitoring module monitors the real-time pressure of the TEP header box in real time and obtains the real-time pressure data of the TEP header box.

[0031] The present invention also provides a header box purging system for a boron recovery system before overhaul of a nuclear power plant, which is applied to the above-mentioned header box purging method for a boron recovery system before overhaul of a nuclear power plant, comprising: a water filling valve, a TEP header box, a water level monitoring module, a pressure monitoring module, an air filling valve, and a control unit;

[0032] The water filling valve is arranged on the water filling pipeline of the TEP header box, the water level monitoring module and the pressure monitoring module are arranged in the TEP header box, the air charging valve is arranged on the air charging pipeline of the TEP header box, and the control unit communicates with the water filling valve, the water level monitoring module, the pressure monitoring module and the air charging valve respectively;

[0033] The control unit is used to control the start and stop of the water filling valve and the air filling valve, and monitor the water volume and pressure in the TEP head box according to the real-time water level information output by the water level monitoring module and the real-time pressure data output by the pressure monitoring module;

[0034] The water filling valve is used to open or close according to the control of the control unit to fill water into the TEP header tank or close the water filling;

[0035] The inflation valve is used to open or close according to the control of the control unit to fill nitrogen into the TEP head box or stop inflation;

[0036] The water level monitoring module is used to monitor the real-time water level information in the TEP header box and send it to the control unit;

[0037] The pressure monitoring module is used to monitor the real-time pressure in the TEP head box and send it to the control unit.

[0038] The head box purge system of the boron recovery system before overhaul of a nuclear power plant according to the present invention further comprises: a water filling control;

[0039] The water filling control communicates with the water filling valve, and is used to generate a water filling trigger signal or a water filling stop trigger signal, and send the water filling trigger signal or the water filling stop trigger signal to the water filling valve.

[0040] The head box purge system of the boron recovery system before overhaul of a nuclear power plant according to the present invention further includes: a pressure relief control and a pressure relief valve;

[0041] The pressure relief control communicates with the pressure relief valve, and is used to generate a pressure relief opening trigger signal or a pressure relief stopping trigger signal, and send the pressure relief opening trigger signal or the pressure relief stopping trigger signal to the pressure relief valve;

[0042] The pressure relief valve is provided on the pressure relief pipeline of the TEP header box, and is used to start pressure relief according to the pressure relief start trigger signal, or to stop pressure relief according to the pressure relief stop trigger signal.

[0043] The method and system for purging a header tank of a boron recovery system before overhaul of a nuclear power plant according to the present invention have the following beneficial effects: comprising the following steps: Step S1. Filling the TEP header tank with water and monitoring the water volume in the TEP header tank; Step S2. Determining whether the water volume in the TEP header tank reaches a preset value, if so, executing Step S3; if not, continuing to fill the TEP header tank with water; Step S3. Stopping water filling, filling the TEP header tank with nitrogen, and monitoring the real-time pressure of the TEP header tank in real time; Step S4. Determining whether the real-time pressure of the TEP header tank reaches a set pressure, if so, executing Step S5; if not, continuing to fill the TEP header tank with nitrogen; Step S5. Opening the pressure relief valve and monitoring the real-time pressure of the TEP header tank; Step S6. Determining whether the real-time pressure in the TEP header tank drops to a pressure threshold, if not, continuing to monitor; if so, returning to Step S3 and repeating Steps S3 to S6 a preset number of times. The present invention can significantly reduce the critical path time of the work, improve work efficiency, reduce work risks, and save production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0045] Figure 1 This is a flow chart of a method for purging a head box of a boron recovery system before overhaul of a nuclear power plant provided by the present invention;

[0046] Figure 2 The diagram is a schematic diagram of the principle of a head box purge system of a boron recovery system before overhaul of a nuclear power plant provided by the present invention. DETAILED DESCRIPTION

[0047] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0048] refer toFigure 1 , Figure 1 This is a flow chart of a preferred embodiment of a method for purging a head box of a boron recovery system before overhaul of a nuclear power plant provided by the present invention.

[0049] Specifically, such as Figure 1 As shown, the method for purging the head box of the boron recovery system before overhaul of the nuclear power plant includes the following steps:

[0050] Step S1 . Fill the TEP header tank 100 with water, and monitor the water volume in the TEP header tank 100 in real time during the filling process.

[0051] In some embodiments, step S1 includes: the water filling control 11 receives a water filling instruction; the water filling control 11 outputs a water filling trigger signal according to the water filling instruction; the water filling valve 12 opens according to the water filling trigger signal and fills water into the TEP header box 100; during the water filling process of the TEP header box 100, the water level monitoring module 15 monitors the real-time water level information in the TEP header box 100 in real time; and monitors the water volume in the TEP header box 100 according to the real-time water level information.

[0052] Step S2: Determine whether the water volume in the TEP header tank 100 reaches a preset value. If so, execute step S3; if not, continue to fill the TEP header tank 100 with water.

[0053] Step S3: Stop filling water, fill nitrogen into the TEP header box 100, and monitor the real-time pressure of the TEP header box 100 in real time during the filling process.

[0054] In some embodiments, step S3 includes: the control unit 200 outputs a stop water filling control signal; the water filling valve 12 closes in response to the stop water filling control signal to stop filling the TEP header box 100 with water; the control unit 200 outputs a gas filling start signal; the gas filling valve 13 is activated in response to the gas filling start signal and fills the TEP header box 100 with nitrogen; during the gas filling process, the pressure monitoring module 14 monitors the real-time pressure of the TEP header box 100 in real time and outputs real-time pressure data. During the gas filling process, the pressure of the gas filling valve 13 is adjusted to 2 barg to achieve a faster gas filling speed.

[0055] Step S4: Determine whether the real-time pressure of the TEP header box 100 reaches the set pressure. If so, execute step S5; if not, continue to inflate the TEP header box 100.

[0056] In some embodiments, step S4 includes: the control unit 200 compares the real-time pressure data of the TEP head box 100 with the set pressure. If the set pressure is reached, the control unit 200 outputs a stop inflation control signal and outputs a pressure relief start signal. If the set pressure is not reached, the control unit 200 does not output a stop inflation control signal.

[0057] Step S5: Open the pressure relief valve 17 and monitor the real-time pressure of the TEP header tank 100 after the pressure relief valve 17 is opened.

[0058] In some embodiments, step S5 includes: the pressure relief valve 17 receives a pressure relief start signal and starts pressure relief according to the pressure relief start signal; during the pressure relief process, the pressure monitoring module 14 monitors the real-time pressure of the TEP header box 100 in real time and obtains real-time pressure data of the TEP header box 100.

[0059] Step S6. Determine whether the real-time pressure in the TEP header box 100 drops to the pressure threshold. If not, continue to monitor the real-time pressure in the TEP header box 100; if so, return to step S3 and repeat steps S3 to S6 for a preset number of times.

[0060] Optionally, in the embodiment of the present invention, the preset value is 70m 3 , set the pressure to 2.5 bar.a, the pressure threshold to 1.15 bar.a. The preset times are generally 6 times.

[0061] The present invention charges the pressure in the TEP header box 100 from 1.15 bar.g to 2.5 bar.a by injecting nitrogen, which takes only 0.5 hours. Compared with the existing 1.15 bar.a to 3 bar.a charging process which takes 2.5 hours according to historical data and file package reminders, the present invention can save 2 hours of work time with one purge, and a total of 12 hours can be saved with 6 purges.

[0062] Furthermore, according to PV=nRT, the hydrogen content is reduced to 1.15 / 2.5=46% of the previous value. Compared with the pressure relief from 3 bar.a to 1.5 bar.a, the hydrogen content is reduced to 1.5 / 3=50% of the previous value. Therefore, the purging effect is better. After purging six times, the effect increases by 60%. The exhaust gas required to discharge from the TEG (exhaust gas treatment system) from 2.52.5 bar.a to 1.15 bar.a is 13.5m 3 , and the pressure reduction from 3 bar.a to 1.5 bar.a requires 15m3 of exhaust gas from TEG. 3 , reduce 1.5m per time 3 Waste gas production, reduced by 9m in 6 times 3 Waste gas production.

[0063] In addition, the TEP header box 100 gas side safety valve is set at 3.5 bar.a, and the water side safety valve is set at 3.8 bar.g (plus 70m 3 The water pressure head is 1.5 bar, and the water side safety valve will be activated when the gas side pressure reaches 3.3 bar.a). Therefore, when charging, the control pressure is 2.5 bar.a, which has a larger margin from the water side and gas side safety valve action setting than 3 bar.a.

[0064] The present invention can significantly save working hours, reduce waste gas production, and has a good purging effect. It has been used many times in overhauls. It can not only greatly reduce the critical path time of the work, but also significantly improve work efficiency, while also reducing work risks and saving production costs.

[0065] refer to Figure 2 , Figure 2 The present invention provides a header box purging system for a boron recovery system before overhaul of a nuclear power plant. The header box purging system for a boron recovery system before overhaul of a nuclear power plant can be applied to the header box purging method for a boron recovery system before overhaul of a nuclear power plant disclosed in an embodiment of the present invention.

[0066] Specifically, such as Figure 2 As shown, the header box purge system of the boron recovery system before overhaul of the nuclear power plant includes: a water filling valve 12, a TEP header box 100, a water level monitoring module 15, a pressure monitoring module 14, an air filling valve 13 and a control unit 200.

[0067] The water filling valve 12 is installed on the water filling line of the TEP header box 100. The water level monitoring module 15 and the pressure monitoring module 14 are installed in the TEP header box 100. The inflation valve 13 is installed on the inflation line of the TEP header box 100. The control unit 200 communicates with the water filling valve 12, the water level monitoring module 15, the pressure monitoring module 14, and the inflation valve 13 respectively. The water level monitoring module 15 and the pressure monitoring module 14 can be installed inside the TEP header. The specific installation location will be based on the actual product configuration and is not specifically limited by this invention.

[0068] Among them, the control unit 200 is used to control the start and stop of the water filling valve 12 and the air filling valve 13, and to monitor the water volume and pressure in the TEP header box 100 according to the real-time water level information output by the water level monitoring module 15 and the real-time pressure data output by the pressure monitoring module 14; the water filling valve 12 is used to open or close according to the control of the control unit 200 to fill water into the TEP header box 100 or stop filling water; the air filling valve 13 is used to open or close according to the control of the control unit 200 to fill nitrogen into the TEP header box 100 or stop filling; the water level monitoring module 15 is used to monitor the real-time water level information in the TEP header box 100 in real time and send it to the control unit 200; the pressure monitoring module 14 is used to monitor the real-time pressure in the TEP header box 100 in real time and send it to the control unit 200.

[0069] Furthermore, if Figure 2 As shown, the head box purge system of the boron recovery system before overhaul of the nuclear power plant also includes: a water filling control 11; the water filling control 11 communicates with the water filling valve 12, is used to generate a water filling trigger signal or a stop water filling trigger signal, and send the water filling trigger signal or the stop water filling trigger signal to the water filling valve 12.

[0070] Furthermore, ifFigure 2 As shown, the head box purging system of the boron recovery system before the nuclear power plant overhaul further comprises a pressure relief control 16 and a pressure relief valve 17; the pressure relief control 16 is in communication with the pressure relief valve 17, and is configured to generate a pressure relief start trigger signal or a pressure relief stop trigger signal and send the pressure relief start trigger signal or the pressure relief stop trigger signal to the pressure relief valve 17.

[0071] The pressure relief valve 17 is arranged on a pressure relief pipeline of the TEP head box 100, and is configured to start pressure relief according to the pressure relief start trigger signal or stop pressure relief according to the pressure relief stop trigger signal.

[0072] The various embodiments are described in a progressive manner in the specification, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be mutually referred to. For the device disclosed by the embodiments, since it corresponds to the method disclosed by the embodiments, the description is relatively simple, and the relevant parts can be referred to the method part.

[0073] The skilled person can further realize that the units and algorithm steps of the examples described in combination with the embodiments disclosed herein can be realized by electronic hardware, computer software or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the components and steps of the examples have been described in a general manner in the above description. Whether the functions are realized in hardware or software depends on the specific application and design constraints of the technical solution. The skilled person can use different methods to realize the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0074] The steps of the method or algorithm described in combination with the embodiments disclosed herein can be directly implemented by hardware, a software module executed by a processor, or a combination of the two. The software module can be placed in a random access memory (RAM), a memory, a read-only memory (ROM), an electrically programmable ROM, an electrically erasable programmable ROM, a register, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.

[0075] The above embodiments are only for illustrating the technical concept and characteristics of the present application, and the purpose is to enable those skilled in the art to understand the content of the present application and implement it accordingly, and cannot limit the protection scope of the present application. Any equivalent changes and modifications made within the scope of the claims of the present application shall be within the scope of the claims of the present application.

Claims

1. A method for purging the head box of a boron recovery system before overhaul of a nuclear power plant, characterized in that: The following steps are involved: Step S1. Filling the TEP header tank with water and monitoring the water volume in the TEP header tank in real time during the filling process; Step S2. Determine whether the water volume in the TEP header tank reaches a preset value. If so, proceed to step S3. If not, continue filling the TEP header tank with water; the preset value is 70 m³. Step S3. Stop filling water, fill nitrogen into the TEP header box, and monitor the real-time pressure of the TEP header box in real time during the filling process; Step S4. Determine whether the real-time pressure of the TEP header box reaches the set pressure. If so, execute step S5. If not, continue to inflate the TEP header box. The set pressure is 2.5 bar.a. Step S5. Open the pressure relief valve and monitor the real-time pressure of the TEP header tank after opening the pressure relief valve; Step S6. Determine whether the real-time pressure in the TEP header box drops to the pressure threshold. If not, continue to monitor the real-time pressure in the TEP header box; if so, return to step S3 and repeat steps S3 to S6 for a preset number of times; the pressure threshold is 1.15 bar.a.

2. The method for purging the head box of a boron recovery system before overhaul of a nuclear power plant according to claim 1, characterized in that: The step S1 comprises: The water filling control receives a water filling instruction; The water filling control outputs a water filling trigger signal according to the water filling instruction; The water filling valve opens according to the water filling trigger signal and fills water into the TEP header tank; During the water filling process of the TEP header box, the water level monitoring module monitors the real-time water level information in the TEP header box in real time; The water volume in the TEP header tank is monitored based on the real-time water level information.

3. The method for purging the head box of a boron recovery system before overhaul of a nuclear power plant according to claim 1, characterized in that: The step S3 comprises: The control unit outputs a water filling stop control signal; The water filling valve is closed according to the stop water filling control signal to stop filling water into the TEP header tank; The control unit outputs a charging start signal; The charging valve is activated according to the charging start signal and fills nitrogen into the TEP head box; During the inflation process, the pressure monitoring module monitors the real-time pressure of the TEP head box in real time and outputs real-time pressure data.

4. The method for purging the head box of a boron recovery system before overhaul of a nuclear power plant according to claim 3, characterized in that: During the inflation process, the valve of the inflation valve is adjusted to 2 barg.

5. The method for purging the head box of a boron recovery system before overhaul of a nuclear power plant according to claim 1, characterized in that: The step S4 comprises: The control unit compares the real-time pressure data of the TEP head box with the set pressure. If the set pressure is reached, the control unit outputs a stop inflation control signal and a pressure relief start signal. If the set pressure is not reached, the control unit does not output a stop inflation control signal.

6. The method for purging the head box of a boron recovery system before overhaul of a nuclear power plant according to claim 1, characterized in that: The step S5 comprises: The pressure relief valve receives a pressure relief opening signal and starts pressure relief according to the pressure relief opening signal; During the pressure relief process, the pressure monitoring module monitors the real-time pressure of the TEP header box in real time and obtains the real-time pressure data of the TEP header box.

7. A head box purging system for a boron recovery system before overhaul of a nuclear power plant, applied to the head box purging method for a boron recovery system before overhaul of a nuclear power plant according to any one of claims 1 to 6, characterized in that: include: Water filling valve, TEP header box, water level monitoring module, pressure monitoring module, air filling valve and control unit; The water filling valve is arranged on the water filling pipeline of the TEP header box, the water level monitoring module and the pressure monitoring module are arranged in the TEP header box, the air charging valve is arranged on the air charging pipeline of the TEP header box, and the control unit communicates with the water filling valve, the water level monitoring module, the pressure monitoring module and the air charging valve respectively; The control unit is used to control the start and stop of the water filling valve and the air filling valve, and monitor the water volume and pressure in the TEP head box according to the real-time water level information output by the water level monitoring module and the real-time pressure data output by the pressure monitoring module; The water filling valve is used to open or close according to the control of the control unit to fill water into the TEP header tank or close the water filling; The inflation valve is used to open or close according to the control of the control unit to fill nitrogen into the TEP head box or stop inflation; The water level monitoring module is used to monitor the real-time water level information in the TEP header box and send it to the control unit; The pressure monitoring module is used to monitor the real-time pressure in the TEP head box and send it to the control unit.

8. The head box purge system of the boron recovery system before overhaul of a nuclear power plant according to claim 7, characterized in that: Also includes: water filling controls; The water filling control communicates with the water filling valve, and is used to generate a water filling trigger signal or a water filling stop trigger signal, and send the water filling trigger signal or the water filling stop trigger signal to the water filling valve.

9. The head box purge system of the boron recovery system before overhaul of a nuclear power plant according to claim 7, characterized in that: Also includes: pressure relief controls and valves; The pressure relief control communicates with the pressure relief valve, and is used to generate a pressure relief opening trigger signal or a pressure relief stopping trigger signal, and send the pressure relief opening trigger signal or the pressure relief stopping trigger signal to the pressure relief valve; The pressure relief valve is provided on the pressure relief pipeline of the TEP header box, and is used to start pressure relief according to the pressure relief start trigger signal, or to stop pressure relief according to the pressure relief stop trigger signal.

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