An online monitoring system and method for radioactivity in water

Abstract

The application discloses a water body radioactivity online monitoring system and a monitoring method, and relates to the technical field of water body radioactivity monitoring. The monitoring system comprises a probe device, a probe driver and signal processing device and a data processing device. The probe device comprises a beta particle detector and a gamma ray detector, and is used for detecting beta particles and gamma rays in a water body and outputting detection signals. The probe driver and signal processing device is electrically connected with the beta particle detector and the gamma ray detector, and is used for receiving the detection signals, processing the detection signals and outputting detection data. The data processing device is electrically connected with the probe driver and signal processing device, and is used for receiving the detection data and analyzing the detection data to obtain a monitoring result. The system provided by the application can realize online real-time monitoring of water body radioactivity, and can realize monitoring of water body nuclide content and identification of nuclides.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of water body radioactivity monitoring, in particular to a water body radioactivity online monitoring system and a monitoring method. BACKGROUND

[0002] Radioactive contamination refers to the radioactivity level of radioactive substances being higher than the natural background or exceeding the specified health standards. Water is the source of life, the key to production, and the basis of ecology. Once the water body is contaminated by radioactivity, the radioactive substances can be enriched in the biological body by means of water transport, which can cause significant harm to human health. Water body radioactivity level monitoring is one of the important contents of radiation environmental monitoring. Due to the openness, fluidity and permeability of water, controlling at the source is the most effective method to solve the problem of water body radioactivity pollution. Online real-time radioactivity monitoring for wastewater discharge scenarios that may contain radionuclides can monitor the water radioactivity level of the discharge point in real time, effectively avoiding water radioactivity over-standard discharge.

[0003] Currently, the detection objects of water body radionuclides mainly include alpha, beta and gamma radionuclides, and the measurement methods include laboratory analysis and water body field measurement. Laboratory analysis involves complex steps such as water sampling and water sample treatment, including water sample acidification, evaporation concentration, flocculation precipitation, high-temperature calcination and other operations, and the sample pretreatment is troublesome; this method is a post-monitoring method, which cannot achieve real-time monitoring, and cannot timely find the phenomenon of over-standard discharge; in addition, the chemical treatment process of this method can only save a part of radionuclides, and other volatile and evaporable nuclides such as 14 C、 3 H、 129 I、 131 I will be lost during the treatment process, resulting in inaccurate test results. Water body field measurement generally integrates the sampling and concentration process in a set of equipment, and the whole set of equipment is located beside the measured water body. A large amount of water sample is automatically extracted and then heated and evaporated to concentrate, and the radioactivity concentration reaches the measurable standard for measurement. The advantage of this method is that the sampling process is automatically completed by the equipment without human intervention. The disadvantage of this method is that the evaporation and concentration of a large volume of water sample consumes a large amount of energy and power, and takes a long time, and the measurement result is lagging; volatile nuclides will still be lost during the evaporation process, resulting in inaccurate measurement results. Therefore, it is urgent to propose a technology that can realize real-time monitoring of water body radioactivity for directly measuring water body radioactivity and solving the shortcomings of the current technology.

[0004] The measuring device for real-time monitoring of water body radioactivity on the market at present is mainly a TAWARA_RTM water body radioactivity pollution monitoring system, but the system can only measure alpha and beta total activity, lacks gamma ray detection capability, and has no nuclide identification function; and the system only reduces the gamma background by reducing the thickness of the plastic scintillator, without further optimization; there is no effective processing measure for the measurement background caused by cosmic rays. In addition, the surface of the plastic scintillator is plated with ZnS(Ag), the plating layer is prone to deliquescence, cannot be in contact with the water body, and is not accurate in measurement under low activity. Long-term use will cause the performance of the detector to decrease due to deliquescence of the plating layer, and the service life of the detector is short.

[0005] Therefore, the prior art still needs to be improved and developed. SUMMARY

[0006] In view of the deficiencies of the prior art, the purpose of the present application is to provide a water body radioactivity online monitoring system and a monitoring method, aiming to solve the problems of poor real-time performance of the existing water body radioactivity monitoring equipment, lack of nuclide identification function and the like.

[0007] The technical scheme of the present application is as follows:

[0008] In a first aspect of the present application, a water body radioactivity online monitoring system is provided, comprising:

[0009] A probe device comprising a beta particle detector and a gamma ray detector, for detecting beta particles and gamma rays in the water body and outputting a detection signal;

[0010] A detector driving and signal processing device, which is electrically connected with the beta particle detector and the gamma ray detector, for receiving the detection signal, processing the detection signal and outputting detection data;

[0011] A data processing device, which is electrically connected with the detector driving and signal processing device, for receiving the detection data and analyzing the detection data to obtain a monitoring result.

[0012] Optionally, the beta particle detector comprises an ion-implanted passivated silicon detector.

[0013] Optionally, the probe device further comprises a shielding body surrounding the gamma ray detector.

[0014] Optionally, the gamma ray detector comprises:

[0015] A scintillator for absorbing gamma rays and emitting a light signal;

[0016] A photomultiplier tube, which is optically coupled with the scintillator, for converting the light signal into an electrical signal;

[0017] Circuitry, electrically connected with the photomultiplier tube, for processing the electrical signal to obtain a gamma ray detection signal.

[0018] Optionally, the material of the scintillator comprises at least one of sodium iodide, cesium iodide, bismuth germanate, gadolinium gallium garnet.

[0019] Optionally, the detector driving and signal processing device comprises:

[0020] A voltage driving module for providing driving voltage for the beta particle detector and the gamma ray detector;

[0021] A signal processing module for receiving the detection signal, processing the detection signal and outputting detection data.

[0022] Optionally, the data processing device comprises a beta specific activity calculation module, a gamma specific activity calculation module, a gamma energy spectrum analysis module, a nuclide identification and activity analysis module, a data regular storage and reporting module, and an alarm module.

[0023] Optionally, the gamma ray detector is arranged above the beta particle detector; the water body radioactivity online monitoring system further comprises a deposition prevention and cleaning device, and the deposition prevention and cleaning device comprises a blocking film arranged below the beta particle detector.

[0024] Optionally, the deposition prevention and cleaning device further comprises:

[0025] An unwinding mechanism, a winding mechanism, two interval-arranged rolling shafts arranged between the unwinding mechanism and the winding mechanism, and a cleaning mechanism arranged between the rolling shaft close to the winding mechanism and the winding mechanism;

[0026] The blocking film is arranged on the unwinding mechanism in the form of a film roll, and the blocking film at one end of the film roll passes through the two interval-arranged rolling shafts in turn and is wound by the winding mechanism.

[0027] The blocking film between the two interval-arranged rolling shafts is arranged below the beta particle detector.

[0028] The second application of the present application provides a water body radioactivity online monitoring method based on the water body radioactivity online monitoring device as described above, which comprises the following steps:

[0029] Detecting beta particles and gamma rays in the water body by using the probe device comprising the beta particle detector and the gamma ray detector and outputting detection signals;

[0030] Receiving the detection signals by using the detector driving and signal processing device, processing the detection signals and outputting detection data;

[0031] The detection data is received by a data processing device and analyzed to obtain a monitoring result.

[0032] Beneficial effects: The probe device can directly detect beta particles and gamma rays in the water body at the discharge and output detection signals without prior sampling and sample processing. The detector driving and signal processing device receives the detection signals, processes the detection signals, and outputs detection data. Finally, the data processing device analyzes the detection data to obtain a monitoring result, thereby realizing online real-time monitoring of water body radioactivity. The problem of existing post-detection that cannot timely detect over-standard discharge is effectively solved. The influence of volatile and evaporable radionuclides on the monitoring result during the sampling and sample processing is avoided, especially the influence of the content loss of volatile and evaporable radionuclides during the processing on the monitoring result is avoided, thereby improving the accuracy of the monitoring result. At the same time, the gamma ray detector is used to measure the gamma spectrum of the radionuclide, which can effectively identify the radionuclide. The contribution of cosmic rays to the measurement background can be removed by anticoincidence, effectively solving the problems of poor real-time performance, large radiation measurement background interference, inaccurate measurement, and no radionuclide identification function of the existing device. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 FIG. 1 is a structural schematic diagram of a water body radioactivity online monitoring system in an embodiment of the present application.

[0034] Figure 2 FIG. 2 is a structural schematic diagram of a probe device in an embodiment of the present application.

[0035] Figure 3 FIG. 3 is an exploded view of the probe device in an embodiment of the present application.

[0036] Figure 4 FIG. 4 is a structural schematic diagram of a lower end seat in an embodiment of the present application.

[0037] Figure 5 FIG. 5 is a position schematic diagram of each component when the probe device is mechanically assembled in an embodiment of the present application.

[0038] Figure 6 FIG. 6 is a structural schematic diagram of a top cover in an embodiment of the present application.

[0039] Figure 7 FIG. 7 is a structural schematic diagram of a deposition prevention cleaning device in an embodiment of the present application.

[0040] BRIEF DESCRIPTION OF THE DRAWINGS

[0041] 1, probe device; 11, beta particle detector; 12, gamma ray detector; 121, scintillator; 122, photomultiplier tube; 1221, upper end socket; 1222, lower end socket; 1223, photomultiplier tube body; 1224, first outlet; 1225, second outlet; 1226, screw positioning hole; 123, circuit system; 13, shielding body; 14, shell; 141, first body; 1411, first through hole; 1412, matching groove; 142, second body; 1421, fixed part; 143, detection window; 144, top cover; 1441, socket groove; 1442, second through hole; 2, detector driving and signal processing device; 21, voltage driving module; 211, first voltage driving module; 212, second voltage driving module; 22, signal processing module; 221, analog signal processing module; 222, digital signal processing module; 3, data processing device; 31, beta specific activity calculation module; 32, gamma specific activity calculation module; 33, gamma energy spectrum analysis module; 34, nuclide identification and activity analysis module; 35, data regular storage and reporting module; 36, alarm module; 4, anti-deposition cleaning device; 41, blocking film; 42, unwinding mechanism; 43, winding mechanism; 44, rolling shaft; 45, cleaning mechanism; 5, alarm device; 6, water body; 7, stainless steel support. DETAILED DESCRIPTION

[0042] The present application provides a water body radioactivity online monitoring system and a monitoring method. In order to make the purpose, technical scheme and effect of the present application more clear and explicit, the present application is further described in detail below. It should be understood that the specific embodiments described herein are only used to explain the present application and are not intended to limit the present application.

[0043] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application.

[0044] The terms used herein, such as "vertical", "horizontal", "up", "down", "left", "right" and similar expressions, are only for the purpose of illustration and are not intended to be the only embodiment.

[0045] In the present application, unless otherwise explicitly specified and limited, the first feature is "on" or "under" the second feature can be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature "over", "above" and "on" the second feature can be that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is horizontally higher than the second feature. The first feature "under", "below" and "under" the second feature can be that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is horizontally lower than the second feature.

[0046] When an element is referred to as "fixed to" or "provided on" another element, it can be directly on the other element or there can be an intermediate element. When an element is referred to as "connected to" another element, it can be directly connected to the other element or there can be an intermediate element.

[0047] If the present application embodiments involve descriptions such as "first", "second", etc., the descriptions of "first", "second", etc. are only for description purposes and cannot be understood as indicating or implying the relative importance of the indicated technical features or implying the number of the indicated technical features.

[0048] In addition, it should be noted that the technical solutions of various embodiments of the present application can be combined with each other, but it must be based on the fact that a person skilled in the art can realize it, and when the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist and is not within the protection scope required by the present application.

[0049] The present application embodiment provides a kind of water body radioactivity online monitoring system, wherein, as shown in Figure 1 And 2 It includes:

[0050] Probe device 1, the probe device 1 includes beta particle detector 11 and gamma ray detector 12, for detecting beta particle and gamma ray in water body and outputting detection signal (beta particle detection signal and gamma ray detection signal);

[0051] Detector driving and signal processing device 2 is simultaneously connected with the beta particle detector 11 and gamma ray detector 12 electrically, for receiving the detection signal, processing the detection signal and outputting detection data;

[0052] Data processing device 3 is connected with the detector driving and signal processing device 2 electrically, for receiving the detection data and analyzing the detection data to obtain monitoring result.

[0053] In the embodiment, the probe device can directly detect β particles and γ rays in the water body at the discharge site (which can be nuclear medical radioactive waste liquid, uranium mine seepage liquid, nuclear power plant wastewater, and other wastewater containing β radioactive nuclides) and output detection signals (β particle detection signals and γ ray detection signals) without prior sampling and sample processing. The detector driving and signal processing device receives the detection signals, processes the detection signals, and outputs detection data. Finally, the monitoring results are obtained by analyzing the detection data through the data processing device, thereby realizing online real-time monitoring of the radioactivity of the water body. The problem that the existing post-detection (detection after sampling and sample processing is a post-detection) cannot timely discover over-standard discharge is effectively solved. The influence of the radioactivity nuclides in the sample during the sampling and sample processing process is avoided, especially the volatile and evaporable nuclides (such as 14 C、 3 H、 129 I、 131 I, etc.), which are lost during the processing process, thereby improving the accuracy of the monitoring results. At the same time, the γ ray detector is used to measure the γ energy spectrum of the nuclide, which can effectively identify the nuclide (i.e., determine which nuclides are in the water body). The contribution of cosmic rays to the background measurement can be removed by anticoincidence, effectively solving the problems of poor real-time performance, large radiation measurement background interference, inaccurate measurement, and lack of nuclide identification function of the existing device.

[0054] In specific applications, the probe device can be arranged at the water body to be measured. The detector driving and signal processing device and the data processing device are arranged at the local control node. The probe device, the detector driving and signal processing device, and the data processing device are electrically connected (for example, connected through a multi-core cable), to generate measurement result data, which is transmitted to the artificial control room (or monitoring center) through a data line.

[0055] In the embodiment, the detector driving and signal processing device is electrically connected with the β particle detector and the γ ray detector, that is, the β particle detector and the γ ray detector are in a parallel relationship and are respectively electrically connected with the detector driving and signal processing device. For example, the β particle detector and the γ ray detector are respectively connected with the detector driving and signal processing device through a multi-core cable.

[0056] The beta particles emitted by beta nuclides have a continuous energy distribution, and a large proportion of low-energy particles. Since the beta particles need to penetrate the water medium to be detected, the energy of the beta particles is further reduced. Therefore, in some embodiments, the beta particle detector includes an ion-implanted passivated silicon (PIPS) detector. The PIPS detector is a high-sensitivity beta particle detector based on a large-area passivated planar silicon, which can realize non-contact online monitoring of low-activity beta radioactive water bodies, effectively solve the problem that the existing method cannot realize online monitoring of low-activity beta radioactive water bodies, and avoid the influence of sampling and processing on the measurement of radionuclides in the sample. Specifically, when the beta particles pass through the silicon crystal, they will interact with the electrons in the silicon atoms, causing the electrons to be ionized from the atoms. These ionized electrons will be accelerated by the electric field in the crystal and form an induced charge on the detector electrode. The total amount of induced charge is proportional to the energy size, so the energy size of the beta particles can be determined by measuring the total amount of charge, and then the radioactivity in the water body or the content of the total radionuclides in the water body can be determined. In this embodiment, the PIPS detector can be directly purchased, and it contains an ultra-low-noise circuit system inside, which is used to process the measured charge signal and output the beta particle detection signal.

[0057] In some embodiments, as shown in FIG. 1, the gamma ray detector 12 includes: Figure 2

[0058] a scintillator 121 configured to absorb gamma rays and emit a light signal, the scintillator 121 being disposed adjacent to the beta particle detector 11;

[0059] a photomultiplier tube 122 optically coupled to the scintillator 121 and configured to convert the light signal into an electrical signal;

[0060] a circuit system 123 electrically connected to the photomultiplier tube 122 and configured to process the electrical signal to obtain a gamma ray detection signal. The circuit system 123 can also provide high voltage to the photomultiplier tube 122.

[0061] The gamma ray detector in this embodiment realizes detection of gamma rays and outputs a gamma ray detection signal.

[0062] In some embodiments, the material of the scintillator includes at least one of sodium iodide, cesium iodide, bismuth germanium oxide (BGO), gadolinium gallium aluminum garnet (GAGG), but is not limited thereto. Among them, sodium iodide has the best comprehensive performance and the lowest cost.

[0063] In some embodiments, the photomultiplier tube 122 is optically coupled to the scintillator 121 by silicone grease.

[0064] In some embodiments, as shown in FIG. 1, the gamma ray detector 12 includes: Figure 2 ​As shown, the probe device 1 further comprises a shielding body 13 surrounding the gamma ray detector 12. Further, the shielding body 13 surrounds the scintillator 121 and the photomultiplier tube 122. The shielding body is arranged around the scintillator and the photomultiplier tube, so that the scintillator and the photomultiplier tube can be effectively shielded, and the weight of the shielding body can be reduced under the premise of ensuring the shielding effect.

[0065] In some embodiments, the material of the shielding body comprises at least one of lead, tungsten, iron, and tin, but is not limited thereto.

[0066] In some embodiments, the material of the shielding body is lead. The lead shielding body can shield more than 80% of the solid angle of the gamma radiation around the scintillator and the photomultiplier tube.

[0067] The probe device 1 will be described in detail as follows. Figure 2 and 3 As shown, the probe device 1 comprises:

[0068] a shell 14;

[0069] a beta particle detector 11 arranged in the shell 14;

[0070] a gamma ray detector 12 arranged in the shell 14 and arranged above the beta particle detector 11, the gamma ray detector 12 comprising, from bottom to top, a scintillator 121, a photomultiplier tube 122, and a circuit system 123 (for connection relationship of the scintillator 121, the photomultiplier tube 122, and the circuit system 123, please refer to the above description);

[0071] a shielding body 13 arranged outside the shell and surrounding the scintillator 121 and the photomultiplier tube 122;

[0072] a detection window 143 arranged on the shell 14 and arranged below the beta particle detector 11, for realizing beta particle detection.

[0073] In this embodiment, the gamma ray detector is arranged above the beta particle detector, because the gamma ray has strong penetrating ability and does not need to be in direct contact with the water body.

[0074] The material of the shell can be stainless steel or aluminum alloy. The stainless steel has good corrosion resistance, and the aluminum alloy has light weight. The appropriate shell material can be selected according to actual needs.

[0075] Further, as shown in the figure, Figure 3 the shell 14 comprises:

[0076] a first body 141 for placing the gamma ray detector 12;

[0077] A second body 142 for placing the beta particle detector 11, the second body 142 is fixed on the first body 141 through a fixing part 1421;

[0078] A top cover 144 is covered on the upper part of the first body 141;

[0079] Wherein, the first body and the second body can be cylindrical.

[0080] As shown in Figure 3 , the photomultiplier tube 122 comprises: an upper end socket 1221, a lower end socket 1222, and a photomultiplier tube body 1223, both ends of the photomultiplier tube body 1223 are respectively clamped in the upper end socket 1221 and the lower end socket 1222.

[0081] When assembling, the both ends of the photomultiplier tube body 1223 are respectively clamped in the upper end socket 1221 and the lower end socket 1222 to form the photomultiplier tube 122, then the photomultiplier tube 122 is placed in the first body 141, at the same time, the scintillator 121 (not shown in Figure 3 ) and the circuit system 123 (not shown in Figure 3 ) are also placed in the first body 141 according to the positional relationship described above, then the top cover 144 is covered on the upper part of the first body 141. Further, the beta particle detector 11 is placed in the second body 142, then the second body 142 with the beta particle detector 11 placed inside is fixed on the first body 141 through the fixing part 1421.

[0082] As shown in Figure 3 , the upper end socket 1221 is provided with a first wire outlet 1224;

[0083] The lower end socket 1222 is provided with a second wire outlet 1225, according to actual conditions, when it is needed to lead out the connecting line, the connecting line is led out from the first wire outlet and the second wire outlet.

[0084] As shown in Figure 4 , the lower end socket 1222 is provided with a screw positioning hole 1226 for positioning the lower end socket.

[0085] As shown in Figure 5As shown, the lower part of the first body 141 is provided with a first through hole 1411 (so that the gamma rays penetrate the beta particle detector and directly hit the scintillator), the projection of the first through hole 1411 on the plane perpendicular to the axial direction of the first body 141 covers the projection of the beta particle detector 11 on the plane perpendicular to the axial direction of the first body 141, and a pair of matching grooves 1412 are arranged on both sides of the first through hole 1411; the bottom of the second body 142 is provided with a detection window 143, and the two sides of the second body 142 are provided with fixing parts 1421 (for example, a pair of positioning ears), which are matched with the matching grooves 1412 and used to fix the second body 142 on the first body 141. When the probe device is assembled, the beta particle detector 11 is placed in the second body 142, and the fixing parts 1421 (such as the positioning ears) are clamped in the matching grooves 1412, and then screwed to realize the arrangement of the beta particle detector in the second body and the fixation of the two on the first body 141.

[0086] As shown in Figure 6 The inside of the top cover 144 is provided with a socket groove 1441 for accommodating the circuit system 123. The inside of the socket groove is provided with a second through hole 1442. The connection line inside the probe device can pass through the second through hole and be connected to the outside.

[0087] In some embodiments, as shown in Figure 1 The probe driver and signal processing device 2 comprises:

[0088] A voltage driving module 21 for providing driving voltage for the beta particle detector 11 and the gamma ray detector 12;

[0089] A signal processing module 22 for receiving the detection signal, processing the detection signal and outputting detection data.

[0090] The voltage driving module 21 comprises a first voltage driving module 211 and a second voltage driving module 212 arranged side by side. The first voltage driving module provides high voltage bias power required for the normal operation of the beta particle detector and the gamma ray detector, and the second voltage driving module provides low voltage power required for the normal operation of the circuit system 123 and the circuit system contained in the beta particle detector. The two power supplies are interference-free and have a low ripple coefficient (the ripple peak-to-peak value is not more than 5mV).

[0091] The signal processing module is used for realizing digitization, noise reduction, discrimination, energy spectrum acquisition, time information acquisition and digital anticoincidence of the detection signals (beta particle detection signal and gamma ray detection signal) output by the probe device. The signal processing module 22 comprises an analog signal processing module 221 and a digital signal processing module 222, and the analog signal processing module 221 and the digital signal processing module 222 are electrically connected.

[0092] The analog signal processing module comprises a signal amplifier and a high-speed data acquisition card. After the detection signals output by the probe device are received by the analog signal processing module, the detection signals are input to the signal amplifier first, and then the detection signals are filtered and amplified by the signal amplifier to output analog signals. Then, the analog signals are converted into digital signals by the high-speed data acquisition card, and the digital signals are transmitted to the digital signal processing module. The digital signal processing module (based on FPGA programmable logic technology) receives the digital signals, and performs digital noise reduction, waveform discrimination, energy spectrum acquisition, time information acquisition and digital anticoincidence processing on the digital signals, and then outputs detection data. The detection data are received and processed by the subsequent data processing device 3.

[0093] The power supply mode of the probe driving and signal processing device is not limited in the application, and a 9V battery can be exemplarily used for power supply.

[0094] As shown in Figure 1 The data processing device 3 comprises a beta specific activity calculation module 31, a gamma specific activity calculation module 32, a gamma energy spectrum analysis module 33, a nuclide identification and activity analysis module 34, a data regular storage and reporting module 35 and an alarm module 36.

[0095] The beta specific activity calculation module is used for performing beta specific activity calculation on the detection data. The gamma specific activity calculation module is used for performing gamma specific activity calculation on the detection data. The gamma energy spectrum analysis module is used for performing gamma energy spectrum analysis on the detection data. Specifically, the energy and quantity characteristics of gamma rays in a radioactive nuclide can be obtained by analyzing the gamma energy spectrum in the detection data, so that the content of the radioactive nuclide can be determined. The nuclide identification and activity analysis module is used for performing nuclide identification and activity analysis on the detection data. Specifically, the energy of gamma rays is only related to the nuclear structure and nuclear properties of atomic nuclei, and each radioactive nuclide has unique characteristics in the energy of gamma rays. Therefore, the radioactive nuclide can be identified and quantitatively analyzed by analyzing the gamma energy spectrum analysis result by the nuclide identification and activity analysis module. The data regular storage and reporting module is used for storing and reporting the test data. The alarm module has a predetermined limit value (i.e. discharge threshold value) of the monitoring result. When the obtained monitoring result exceeds the predetermined limit value (for example, the beta nuclide specific activity exceeds the predetermined limit value), an alarm signal is given.

[0096] As shown in Figure 1As shown, the water body radioactivity online monitoring system further comprises an alarm device 5 electrically connected with the data processing device 3, and the data processing device 3 outputs an alarm signal received by the alarm device 5 to give an alarm.

[0097] In some embodiments, the data processing system is further equipped with an operation interface and a display interface (for displaying monitoring results). Specifically, in actual application, when the data processing device gives a measured curve of the physical quantity to be measured changing with time, the operation interface and the display interface facilitate the supervisor to judge the changing trend of the β radioactivity contained in the discharged wastewater according to the curve trend and take necessary early warning measures.

[0098] As shown in Figure 1 and 7 As shown, the γ-ray detector 12 is arranged above the β-particle detector 11; the water body radioactivity online monitoring system further comprises a deposition-preventing cleaning device 4, and the deposition-preventing cleaning device 4 comprises a blocking film 41 located below the β-particle detector 11.

[0099] The deposition-preventing cleaning device 4 further comprises:

[0100] an unwinding mechanism 42, a winding mechanism 43, two interval-arranged rolling shafts 44 arranged between the unwinding mechanism 42 and the winding mechanism 43, and a cleaning mechanism 45 arranged between the rolling shaft 44 close to the winding mechanism 43 and the winding mechanism 43.

[0101] The blocking film is arranged on the unwinding mechanism 42 in the form of a film roll, and the blocking film at one end of the film roll passes through the two interval-arranged rolling shafts 44 in turn and is wound by the winding mechanism 43; the blocking film 41 located between the two interval-arranged rolling shafts is located below the β-particle detector 11.

[0102] As shown in Figure 1 The deposition-preventing cleaning device is used to improve the damage of suspended matters, depositable matters and precipitated minerals in the water body 6 to the probe device itself and the inaccuracy of the measurement results under the condition of long-time unattended service, and avoid the adhesion of the suspended matters in the water to the surface of the β-particle detector to cause abnormal distribution of radionuclides. In use, the blocking film (which can be effectively penetrated by β-particles) is used to block the suspended matters, depositable matters and precipitated minerals in the water, so as to avoid the contact of these matters with the probe device, and the winding mechanism (such as a stepping motor) is used to advance a certain distance (not less than the length of the blocking film contacting the surface of the water) at a fixed time (such as one day or 12 hours) to drive the blocking film to move, so as to ensure the cleanliness of the blocking film by regularly and automatically replacing the blocking film below the β-particle detector. The rolling shaft is used to control the moving direction of the blocking film.

[0103] The barrier film includes one of a polyimide (kapton) film, a polyethylene film, a polypropylene film, and a polyvinyl chloride film, but is not limited thereto. Among them, the kapton film is waterproof, wear-resistant, thin in thickness, and good in mechanical property, and the kapton film with a width of not less than 60 cm is preferably used.

[0104] Further, the cleaning mechanism 45 includes a cleaning brush for brushing off the suspended matters, the depositable matters, and the precipitated minerals in the water body deposited on the barrier film.

[0105] In the embodiment, as shown in Figure 1 and 7 The unwinding mechanism 42 and the winding mechanism 43 can be arranged on the stainless steel support 7.

[0106] The monitoring principle of the water body radioactivity online monitoring device will be described in detail below.

[0107] The probe device is arranged at the water body to be measured, and the beta particle detector (such as a PIPS detector, which is a high-sensitivity beta particle detector based on a large-area passivated planar silicon and can detect low-activity beta radioactive water body) in the probe device is in contact with the water body. When the beta particle passes through the silicon crystal, it will interact with the electrons in the silicon atoms, causing the electrons to be ionized from the atoms. These ionized electrons will be accelerated by the electric field in the crystal and form an induced charge on the detector electrode to obtain a total charge signal (the total charge is proportional to the energy size, so the energy size of the beta particle can be determined by measuring the total charge). The circuit system built in the PIPS detector processes the obtained charge signal and outputs a beta particle detection signal. Meanwhile, the gamma rays in the water body have strong penetrating ability and can be accepted by the gamma ray detector. The scintillator in the gamma ray detector absorbs the gamma ray emission light signal. The photomultiplier tube optically coupled to the scintillator receives the light signal and converts the light signal into an electric signal. The circuit system electrically connected to the photomultiplier tube processes the electric signal to obtain a gamma ray detection signal.

[0108] The probe driving and signal processing device connected with the probe device through the multi-core cable receives the beta particle detection signal and the gamma ray detection signal, in the probe driving and signal processing device, the beta particle detection signal and the gamma ray detection signal are first input to a signal amplifier for filtering and amplification, and then an analog signal is output, then the analog signal is converted into a digital signal through a high-speed data acquisition card, and is transmitted to the digital signal processing module, the digital signal processing module (based on FPGA programmable logic technology) receives the digital signal, and after digital noise reduction, waveform discrimination, energy spectrum acquisition, time information acquisition and digital anti-coincidence processing, output detection data, the detection data is received and processed in the data processing device, and in the data processing device, beta specific activity calculation, gamma specific activity calculation, gamma spectrum analysis, nuclide identification and activity analysis can be performed, the monitoring result is obtained and displayed, the nuclide content monitoring and nuclide identification are realized. The data processing device is built-in with a specified limit value (i.e. discharge threshold value) of the monitoring result, when the obtained monitoring result exceeds the specified limit value (for example, the beta nuclide specific activity exceeds the specified limit value), an alarm signal is given.

[0109] Therefore, the monitoring system can directly monitor the long-time unattended low-activity beta radioactive nuclide contaminated wastewater without sampling treatment, real-time gives the beta radioactive nuclide level in the discharged water body and real-time gives the alarm information when the discharge limit value is exceeded, is used for the supervision of beta radioactive nuclide wastewater discharge, and is convenient for timely grasping the over-standard discharge and convenient for supervision.

[0110] The embodiment of the application also provides a water body radioactivity online monitoring method based on the water body radioactivity online monitoring device as described above.

[0111] S1, using the probe device including a beta particle detector and a gamma ray detector to detect beta particles and gamma rays in the water body and output detection signals;

[0112] S2, using the probe driving and signal processing device to receive the detection signals, processing the detection signals and outputting detection data;

[0113] S3, using the data processing device to receive the detection data and analyze the detection data to obtain a monitoring result, and display the monitoring result.

[0114] The monitoring method provided by the embodiment of the application can realize online real-time monitoring of the radioactivity of a water body, without needing to perform sampling and sample processing in advance, thereby avoiding the influence of sampling and the sample processing process on radionuclides in the sample, especially volatile and evaporable nuclides, which are damaged in the processing process, thereby improving the accuracy of the monitoring result, and effectively solving the problem that existing after-detection cannot timely discover over-standard discharge. Meanwhile, the monitoring method can realize monitoring of the content of the nuclides and identification of the nuclides.

[0115] It should be understood that the application is not limited to the above examples, and can be improved or changed according to the above description for those of ordinary skill in the art, and all these improvements and changes shall belong to the protection scope of the appended claims of the application.

Claims

1. An online monitoring system for radioactivity in a body of water, characterized in that, The probe device comprises a shell, a beta particle detector for detecting beta particles in a water body and outputting a detection signal, and a gamma ray detector for detecting gamma rays in the water body and outputting a detection signal, which are arranged in the shell; the gamma ray detector is arranged above the beta particle detector and comprises, from bottom to top, a scintillator, a photomultiplier tube and a circuit system; the scintillator is used for absorbing gamma rays and emitting an optical signal; the photomultiplier tube is optically coupled to the scintillator and is used for converting the optical signal into an electrical signal; and the circuit system is electrically connected to the photomultiplier tube and is used for processing the electrical signal to obtain a gamma ray detection signal; a shielding body is arranged outside the shell and surrounds the scintillator and the photomultiplier tube; the shielding body is made of at least one of lead, tungsten, iron and tin; a detection window is arranged on the shell and below the beta particle detector, and is used for beta particle detection; a detector driving and signal processing device is electrically connected to the beta particle detector and the gamma ray detector, and is used for receiving the detection signals, processing the detection signals and outputting detection data; and a data processing device is electrically connected to the detector driving and signal processing device, and is used for receiving the detection data and analyzing the detection data to obtain monitoring results. The shell comprises: a first body for placing the gamma ray detector; a first through hole is arranged at the lower part of the first body, the projection of the first through hole on a plane perpendicular to the axial direction of the first body covers the projection of the beta particle detector on the plane perpendicular to the axial direction of the first body, and a pair of matching grooves are arranged on both sides of the first through hole; a second body for placing the beta particle detector, which is fixed to the first body through a fixing part; a top cover arranged on the upper part of the first body; the beta particle detector is an ion-implanted passivated silicon detector; the detector driving and signal processing device comprises: a voltage driving module for providing driving voltage for the beta particle detector and the gamma ray detector; a signal processing module for receiving the detection signals, processing the detection signals and outputting detection data; the signal processing module comprises an analog signal processing module and a digital signal processing module, which are electrically connected; the analog signal processing module comprises a signal amplifier and a high-speed data acquisition card; and the digital signal processing module is used for receiving digital signals, and performing digital noise reduction, waveform discrimination, energy spectrum acquisition, time information acquisition and digital anticoincidence processing to output detection data. The material of the scintillator comprises at least one of sodium iodide, cesium iodide, bismuth germanate and gadolinium gallium garnet. The data processing device comprises a beta specific activity calculation module, a gamma specific activity calculation module, a gamma energy spectrum analysis module, a nuclide identification and activity analysis module, a data regular storage and reporting module and an alarm module. ​ ​ ​ 2. The online monitoring system of radioactivity in a body of water according to claim 1, characterized in that, ​ 3. The online monitoring system of claim 1, wherein, ​ 4. The online monitoring system of claim 1, wherein, The water body radioactivity online monitoring system further comprises a deposition-preventing cleaning device, and the deposition-preventing cleaning device comprises a blocking film located below the beta particle detector.

5. The online monitoring system of claim 4, wherein, The deposition-preventing cleaning device further comprises: an unwinding mechanism, a winding mechanism, two interval-arranged rolling shafts arranged between the unwinding mechanism and the winding mechanism, and a cleaning mechanism arranged between the rolling shaft near the winding mechanism and the winding mechanism; the blocking film in the form of a film roll is arranged on the unwinding mechanism, and the blocking film at one end of the film roll passes through the two interval-arranged rolling shafts in turn and is wound by the winding mechanism; the blocking film located between the two interval-arranged rolling shafts is located below the beta particle detector.

6. A method for online monitoring of radioactivity in a water body based on the device for online monitoring of radioactivity in a water body according to any one of claims 1-5, characterized in that, The method comprises the steps of: detecting beta particles and gamma rays in a water body by using a probe device comprising a beta particle detector and a gamma ray detector and outputting a detection signal; receiving the detection signal, processing the detection signal, and outputting detection data by using a detector driving and signal processing device; receiving the detection data, analyzing the detection data, and obtaining a monitoring result by using a data processing device.

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