[0053] In the following, the method and system for monitoring the pressure boundary leakage of the primary loop of the core station of the present invention will be further explained and illustrated in conjunction with the accompanying drawings and embodiments.
[0054] figure 2 It is a structural diagram of the first embodiment of the system of the present invention, such as figure 2 As shown, in the first embodiment, the system of the present invention includes:
[0055] The sample control device 301, which is arranged in the containment 200, is used to obtain atmospheric samples in the pressure boundary area of the primary circuit;
[0056] The fluorine 18 detection device 302, which is set outside the containment 200, is connected to the sample control device 301 through a pipe, and is used to receive the atmospheric sample obtained by the sample control device 301, filter and measure the aerosol in the atmospheric sample to measure Count rate and output of total aerosol radiation;
[0057] The first pressure gauge 303 and the thermometer 304 are both installed outside the containment 200 on the pipeline between the sample control device 301 and the fluorine 18 detection device 302, and are used to measure the pressure and temperature of atmospheric samples;
[0058] The first processor 305 is arranged outside the containment vessel 200 and is electrically connected to the fluorine 18 detection device 302, the first pressure gauge 303 and the thermometer 304, and is configured to receive the total aerosol radiation output from the fluorine 18 detection device 302 with a count rate of Calculate the activity of the fluorine 18 in the form of aerosol, according to the received first pressure value of the atmospheric sample output by the first pressure gauge 303, the temperature value of the atmospheric sample output by the thermometer 304 and the reactor power signal, combined with the volume of the fluorine 18 detection device 302 Calculate the volume of aerosol in the standard state, then use the calculated activity of fluorine 18 in the form of aerosol and the volume of aerosol in the standard state to calculate the specific activity of fluorine 18 in the form of aerosol, and then calculate the specific activity of the aerosol. The specific activity of the fluorine 18 in the form of sol is compared with a preset threshold to determine whether the primary circuit leaks. In this embodiment, if the first processor determines that the primary circuit pressure boundary is leaking, an alarm will be issued;
[0059] The first sampling pump 309 is arranged outside the containment 200 and connected between the fluorine 18 detection device 302 and the containment 200 through a pipeline, for the sample control device 301 to collect atmospheric samples from the containment and the collected atmospheric samples in the system China Mobile provided the impetus.
[0060] In this embodiment, the sample control device 301 can collect atmospheric samples from areas prone to leakage at the pressure boundary of the primary circuit, such as the top area of the control rod drive mechanism, thereby increasing the sensitivity of the system of the present invention to leakage monitoring. When it is necessary to obtain atmospheric samples from several sensitive areas, the sample control device 301 successively selects the atmospheric samples collected from several sensitive areas, so that the several collected atmospheric samples enter the system in an orderly manner for detection. The sample control device 301 can also realize cyclic scanning and sampling from different sensitive areas. After the sample control device 301 completes the selection of the sampling area, the first sampling pump 309 provides power for the sampling process to allow the atmospheric sample in the selected area to enter the system of the present invention. The first sampling pump 309 also provides the atmospheric sample in the system. The movement in the vehicle provides power and ultimately returns the atmospheric sample to the containment vessel 200.
[0061] In this embodiment, the fluorine 18 detection device 302 is surrounded by a lead screen to reduce the background radiation therein, a glass fiber filter 3021 is arranged in the center, and a first scintillator detector is arranged at the end connected to the first processor 303 3022. The glass fiber filter 3021 is used to filter out the aerosol in the atmospheric sample of the fluorine 18 detection device 302. The first scintillator detector 3022 measures the count rate of the total radiation of the aerosol under the filtration and sends it to the first treatment. The air sample in the containment vessel 200 contains a variety of components, one of which is a variety of nuclides in the form of aerosol. Because the prior art only measures the radiation of the whole aerosol, it cannot be accurate. And quickly reflect the leakage of the pressure boundary of the primary circuit. The present invention uses fluorine 18 in the form of aerosol as the measurement object, because the decay of fluorine 18 will produce positrons. Because positrons are unstable, they are very easy to interact with electrons in the medium to produce annihilation effects, and the two energies are both 0.511. MeV and opposite gamma photons. Therefore, the first processor 305 can analyze the count rate of aerosol radiation in the energy range of 0.460 to 0.560 Mev based on the received count rate information of the total aerosol radiation, and then obtain the fluorine 18 activity. The first processor 305 then combines the standard state calculated based on the received first pressure value of the atmospheric sample output by the first pressure gauge 303, the temperature value of the atmospheric sample output by the thermometer 304, the reactor power signal, and the volume of the fluorine 18 detection device 302. Calculate the specific activity of fluorine 18 in the form of aerosol (in Bq/cm 3 ).
[0062] In this embodiment, the first processor 305 compares the calculated specific activity of the fluorine 18 in the form of aerosol with a preset threshold to determine whether the pressure boundary of the primary circuit leaks. The preset threshold value is given according to different nuclear power plants and can be determined by experiment.
[0063] In this embodiment, the first processor 305 not only issues an alarm to the main control room when the calculated specific activity of the fluorine 18 in the form of aerosol exceeds a preset threshold value, and reminds the operator of the pressure boundary of the primary circuit. There may be a leak. When any signal received by it is lost or abnormal or the first sampling pump stops working, the first processor 305 will also send an alarm to the main control room and explain the cause of the error.
[0064] image 3 It is a structural diagram of the second embodiment of the system of the present invention, such as image 3 As shown, in the second embodiment, the system of the present invention further includes:
[0065] An iodine filter 306 arranged on the pipeline between the fluorine 18 detection device 302 and the first sampling pump 309 outside the containment vessel 200 is used to filter the iodine in the atmospheric sample output from the fluorine 18 detection device 302;
[0066] The inert gas detection device 307, which is arranged outside the containment vessel 200 and on the pipeline between the iodine filter 306 and the first sampling pump 309, is used for radiation measurement of the inert gas in the atmospheric sample output from the iodine filter 306 to detect Count rate and output of total radiation of inert gas;
[0067] A second pressure gauge 320 arranged on the pipeline between the iodine filter 306 and the inert gas detection device 307 outside the containment vessel 200;
[0068] The second processor 308, which is provided outside the containment vessel 200 and is electrically connected to the thermometer 304, the second pressure gauge 320, and the inert gas detection device 307, is used to receive the inert gas total radiation count rate output by the inert gas detection device 307 Calculate the activity of the inert gas; used to receive the second pressure value of the atmospheric sample output by the second pressure gauge 320, the temperature value of the atmospheric sample output by the thermometer 304, and combine with the volume of the inert gas detection device 307 to calculate the inert gas in the standard state Volume; then use the calculated activity of the inert gas and the volume of the inert gas in the standard state to calculate the specific activity of the inert gas, and compare it with the preset threshold to determine whether a circuit leaks.
[0069] In this embodiment, the inert gas monitoring device 307 is surrounded by a lead screen to reduce background radiation, and the second scintillator detector 3071 is provided at one end of the electrical connection with the second processor 308. The second scintillator detector 3071 is arranged at the center of the inert gas monitoring device 307, thereby obtaining a detection angle of 4π.
[0070] In this embodiment, the rest of the situation is the same as that of the first embodiment, and will not be repeated here.
[0071] In this embodiment, the iodine filter 306 filters the iodine in the atmospheric sample passing through the fluorine 18 detection device 302 to avoid the influence of iodine on the inert gas measurement.
[0072] In this embodiment, the activity of the inert gas calculated by the second processor 308 is obtained by measuring the count rate of beta rays. Since the aerosol and iodine in the atmospheric sample are respectively filtered in the glass fiber filter 3021 and the iodine filter 306 in the fluorine 18 detection device 302, the pressure of the atmospheric sample must be re-measured at this time. However, the temperature of the atmospheric sample hardly changes, so the temperature measured by the thermometer 304 can still be used. Therefore, the second processor 308 calculates the volume of the inert gas in the standard state according to the second pressure value of the atmospheric sample output by the second pressure gauge 320, the temperature value of the atmospheric sample output by the thermometer 304, and the volume of the inert gas detection device 307; Calculate the specific activity of the inert gas with the calculated activity of the inert gas and the volume of the inert gas in the standard state, and compare it with the preset threshold to judge whether the primary circuit is leaking, and send it to the main control room The alarm reminds the operator that there may be a leak somewhere in the pressure boundary of the primary circuit.
[0073] In this embodiment, the second processor 308 will also send an alarm to the main control room and explain the cause of the error when any signal received by it is lost or abnormal, or the differential pressure signal of the iodine filter 306 is abnormal.
[0074] In the third embodiment of the system of the present invention, the system of the present invention is provided with a flow meter 310 outside the containment vessel 200, on the pipe connecting the inert gas detection device 307 and the first sampling pump 309, the flow meter 310 and the second processor 308 is electrically connected; a first regulating valve 311 is provided on the pipe connecting the flow meter 310 and the first sampling pump 309, and the flow of the atmospheric sample is within a certain range through the control of the flow meter 310 and the first regulating valve 311 , To ensure the accuracy of the specific activity measurement of fluorine 18 and inert gas;
[0075] An electric shut-off valve 312 is provided in the containment 200, on the pipeline between the sample control device 301 and the fluorine 18 detection device 302; a check valve 313 is provided on the pipeline connecting the first sampling pump 309 to the containment 200; The pipeline connecting the shut-off valve 312 and the first pressure gauge 303 and the pipeline connecting the check valve 313 and the first sampling pump 309 pass through the containment 200 through the containment 200 penetrating member, respectively. In this embodiment, the rest of the situation is the same as in the second embodiment, and will not be repeated here.
[0076] In the fourth embodiment of the system of the present invention, the system of the present invention is provided with a second regulating valve 314 outside the containment vessel 200 and on the pipeline between the electric shut-off valve 312 and the first pressure gauge 303; A third regulating valve 315 is provided on the pipe connecting the outer check valve 311 and the first sampling pump 302. The electric shut-off valve 312 and the check valve 311 are both in the containment 200, and workers will not enter the containment 200. In order to block the pipeline when the electric shut-off valve 313 and the check valve 311 are damaged, it is safe A second regulating valve 314 and a third regulating valve 315 are provided outside the housing. In this embodiment, the rest of the situation is the same as in the third embodiment, and will not be repeated here.
[0077] In the fifth embodiment of the system of the present invention, the system of the present invention further includes a compressed air device 316 and a natural air inlet 317 which are arranged outside the containment vessel 200, and pass through the fourth regulating valve 318 and the fifth regulating valve 319 through pipelines. Connected to the pipeline between the second regulating valve 314 and the first pressure gauge 303. In this embodiment, the natural air inlet 317 provides natural air, and the first sampling pump provides the natural air movement power to clean the devices and connecting pipes in the system. In this embodiment, the rest of the cases are the same as in the fourth embodiment, and will not be repeated here.
[0078] In the sixth embodiment of the present invention, the system of the present invention further includes: a bypass filter 321 arranged outside the containment vessel 200, and both ends of the bypass filter pass through the pipeline through the sixth regulating valve 322 and the seventh regulating valve. The valve 323 is connected to the pipeline between the thermometer 304 and the fluorine 18 detection device 302 and the pipeline between the iodine filter 306 and the second pressure gauge 320. In this embodiment, the bypass filter 321 is used when the fluorine 18 detection device 302 is under maintenance to filter out aerosol and iodine in the atmospheric sample, so that the subsequent inert gas detection device 307 can continue to perform detection.
[0079] Figure 4 It is a structural diagram of the seventh embodiment of the system of the present invention, such as Figure 4 As shown, the system of the present invention further includes a second sampling pump 324 connected in parallel with the first sampling pump 309 through a pipeline. The second sampling pump 324 is a backup pump. If the first sampling pump 309 is out of service, it will replace the first sampling pump 309 to work.
[0080] On the basis of the seventh embodiment of the system of the present invention, a valve can be provided on the pipeline to enhance the controllability of the overall system, and is also convenient for engineering installation and repair. E.g, Figure 5 It is a structural diagram of the eighth embodiment of the system of the present invention, such as Figure 5 As shown, the system of the present invention also includes an eighth regulating valve 325 arranged on the pipeline between the second regulating valve 314 and the first pressure gauge 303. In this embodiment, when the system of the present invention is out of operation, the compressed air device 316 can be used to provide compressed air to clean up the dust deposits in the upstream pipeline of the air supply point. At this time, the electric shutoff valve 312, the second regulating valve 314, and the fourth regulating valve 318 are opened, and the eighth regulating valve 325 and the fifth regulating valve 319 are closed. The natural air inlet 317 is used to provide natural air, and the first sampling pump provides the natural air movement power to clean each device and connecting pipes in the system.
[0081] In the first to the eighth embodiments of the system of the present invention, there will be a phenomenon that the aerosol adheres to the internal measurement of pipes, valves, etc., thereby causing losses. In the actual calculation process, the loss rate needs to be evaluated. It is generally estimated based on the size of the pipe, the smoothness of the inner wall, etc., or it can be obtained by experimental methods based on the implementation of the system. In the calculation of the first processor 305, the calculated loss value is added to its calculation. In addition, the first pressure gauge 303 and the thermometer 304 can be used to compensate and calculate the concentration of nuclide in the form of aerosol in the standard state. Because this time is not the focus of the present invention, no further explanation will be given. Those skilled in the art can implement the above operations according to the prompts in the present invention.
[0082] In the seventh embodiment of the system of the present invention, the first sampling pump 309, the second sampling pump 324, the electric shut-off valve 312, and the first regulating valve 311 in the system can be controlled by the first processor 305 and issued when they fail. The alarm can also be controlled by the second processor 308 and send an alarm when they fail. The specific situation can be selected according to the needs of the engineering design.
[0083] In the system of the present invention, the specific driving type of the valve which is not explained as the driving mode is also selected according to the needs of engineering design.
[0084] The present invention provides a method for monitoring the pressure boundary leakage of the primary circuit of a nuclear power plant. The application of the method in the pressure boundary leakage measurement system of the primary circuit of a nuclear power plant is the first embodiment. The execution flow chart of the first embodiment of the method of the present invention is as follows Image 6 As shown, in this embodiment, the method includes the following steps:
[0085] A. The sample control device 301 and the first sampling pump 309 work together to obtain atmospheric samples from the pressure boundary area of the primary circuit in the containment 200, and then proceed to step B;
[0086] B. The obtained atmospheric sample is measured by the first pressure gauge 303 and thermometer 304, and then passes through the fluorine 18 detection device 302, which filters the aerosol in the atmospheric sample, and performs radiation measurement on the aerosol to obtain the total aerosol radiation Count rate, go to step C;
[0087] C. The first processor 305 receives the count rate of the total aerosol radiation output by the fluorine 18 detection device (302), the first pressure value of the atmospheric sample output by the first pressure gauge (303), and the thermometer (304) ) The output air sample temperature value and the reactor power signal, combined with the volume of the fluorine 18 detection device (302), calculate the specific activity of fluorine 18 in the form of aerosol, and calculate the specific activity of fluorine 18 in the form of aerosol with The preset threshold value is compared to determine whether the pressure boundary of the primary circuit is leaking, and then step D is performed; the aerosol-form fluorine 18 activity is calculated according to the count rate of the total aerosol radiation measured by the fluorine 18 detection device 302; The first pressure value of the atmospheric sample measured by the first pressure gauge 303, the temperature value of the atmospheric sample measured by the thermometer 304, and the reactor power signal are combined with the volume of the fluorine 18 detection device 302 to calculate the aerosol volume in the standard state; then use the calculated The specific activity of fluorine 18 in the form of aerosol and the volume of aerosol in the standard state are calculated to calculate the specific activity of fluorine 18 in the form of aerosol, and the calculated specific activity of fluorine 18 in the form of aerosol is compared with the preset threshold Compare to determine whether the primary circuit leaks, go to step D;
[0088] D. The atmospheric sample is drawn back to the containment 200 by the first sampling pump 309.
[0089] The execution flow chart of the second embodiment of the method of the present invention is as follows Figure 7 As shown, in the second embodiment of the method of the present invention, the rest of the situation is the same as that of the first embodiment of the method of the present invention, and there are steps between steps C and D of the first embodiment:
[0090] C1. The atmospheric sample passing through the fluorine 18 detection device 302 passes through the iodine filter 306 to filter the iodine in the atmospheric sample, and then goes to step C2;
[0091] C2. The atmospheric sample passing through the iodine filter 306 is measured by the second pressure gauge 320 and then passed through the inert gas detection device 307. The inert gas detection device 307 measures the inert gas in the atmospheric sample to measure the total radiation count rate of the inert gas And output, go to step C3;
[0092] C3. The second processor 308 receives the total radiation count rate of the inert gas output by the inert gas detection device (307), the second pressure value of the atmospheric sample output by the second pressure gauge (320), and the thermometer (304) The output atmospheric sample temperature value, combined with the volume of the inert gas detection device (307), calculates the specific activity of the inert gas, and compares it with the preset threshold to determine whether the pressure boundary of the primary circuit leaks, and then go to step D .
[0093] In step C, the specific steps for the first processor 305 to calculate the specific activity of the fluorine 18 include: the first processor 305 calculates the fluorine 18 in the form of aerosol according to the count rate of the total aerosol radiation measured by the fluorine 18 detection device 302 According to the first pressure value of the atmospheric sample measured by the first pressure gauge 303, the temperature value of the atmospheric sample measured by the thermometer 304, and the reactor power signal, combined with the volume of the fluorine 18 detection device 302 to calculate the volume of aerosol in the standard state; The calculated specific activity of fluorine 18 in aerosol form and the volume of aerosol under standard conditions are then used to calculate the specific activity of fluorine 18 in aerosol form.
[0094] In step C3, the specific steps of the second processor 308 calculating the specific activity of the inert gas include: the second processor 308 calculates the activity of the inert gas according to the count rate of the total radiation of the inert gas measured by the inert gas detection device 307 Degree; According to the second pressure value of the atmospheric sample measured by the second pressure gauge 320 and the temperature value of the atmospheric sample measured by the thermometer 304, combined with the volume of the inert gas detection device 307 to calculate the volume of the inert gas in the standard state; and then use the calculated inertness The specific activity of the inert gas is calculated by the activity of the gas and the volume of the inert gas in the standard state.
[0095] In the specific implementation process, the system and method according to the present invention can be appropriately improved to meet the requirements of specific situations. Therefore, it can be understood that the specific embodiments according to the present invention are merely exemplary and are not used to limit the protection scope of the present invention.
