Water body total radioactivity and nuclide on-line measurement system

Abstract

The invention relates to the technical field of nuclear radiation monitoring, in particular to a water body total radioactivity and nuclide on-line measurement system which comprises a gamma detector, a beta detector, an alpha detector and a water treatment component, the water treatment component extracts a water body sample and processes the water body sample, and then the water body sample passes through the gamma detector, the beta detector and the alpha detector; the gamma detector is arranged in a first shielding body, and the beta detector and the alpha detector are arranged in a second shielding body; the water treatment assembly provided by the invention is responsible for extracting and treating a water body sample, so that the water body sample sequentially passes through various detectors and a gamma detector to obtain a gamma energy spectrum of the water body sample, and a beta detector and an alpha detector respectively obtain beta and alpha total activity of the water body sample, and accurate detection of different types of radiation is realized.

Description

Technical Field

[0001] The present invention relates to the field of nuclear radiation monitoring technology, and in particular to an online measurement system for total radioactivity and nuclides in water bodies. By integrating various types of radiation detectors, the system is used for real-time monitoring of α, β, γ radioactive activities and nuclides in water bodies. The system is applied to online monitoring of radiation levels and over-threshold alarms in water bodies such as nuclear facilities, drinking water, and industrial wastewater, thereby improving the ability to quickly detect and respond to radiation pollution in water bodies. Background Art

[0002] With the development of nuclear energy utilization and nuclear technology, monitoring of radionuclides in water bodies has become a key demand in environmental protection, especially in the field of nuclear emergency. At present, a variety of low-background radioactivity measurement systems have been developed at home and abroad, but most of the existing systems use offline sampling and analysis technology, such as liquid scintillation counter (LSC). Although it can effectively detect the α and β activities in water samples, it is difficult to meet the needs of real-time monitoring due to the need for manual sampling and laboratory analysis. The TAWARA_RTM system developed abroad realizes real-time online monitoring of radioactivity in tap water, but its equipment is expensive, maintenance cost is high, and there are limitations in nuclide identification, and it is impossible to take into account the real-time monitoring of multiple radiation types at the same time.

[0003] Domestic research and application of online monitoring of water radioactivity are relatively lagging behind, mainly relying on laboratory analysis methods to measure total radioactivity and nuclides, which cannot reflect the radioactivity level of water in real time. Therefore, an efficient, accurate and economical online measurement system is needed to meet the needs of rapid detection of radioactive contamination in water in practical applications.

[0004] Based on this, the present invention proposes an online measurement system for total radioactivity and nuclides in water bodies, so as to realize comprehensive and real-time monitoring of radioactive contamination in water bodies. Summary of the invention

[0005] The technical problem to be solved by the present invention is that the water body radioactivity and nuclide detection means in the prior art cannot meet the real-time online monitoring needs, and there is a problem of insufficient accuracy in nuclide identification and low background measurement. The purpose is to provide an online measurement system for total water radioactivity and nuclides, which realizes real-time and accurate measurement of α, β, γ radioactive activities and nuclide types in water bodies, and has low background and high precision monitoring capabilities, and can continuously monitor water body radiation pollution and alarm for exceeding threshold values.

[0006] The present invention is achieved through the following technical solutions:

[0007] A system for measuring total radioactivity and nuclides in water on-line comprises: a γ detector, a β detector, an α detector and a water treatment component, wherein the water treatment component extracts water samples and processes the water samples before passing through the γ detector, the β detector and the α detector, the γ detector is arranged in a first shielding body, and the β detector and the α detector are arranged in a second shielding body;

[0008] The gamma detector acquires the gamma energy spectrum of the water sample, the beta detector acquires the total beta activity of the horizontal sample, and the alpha detector acquires the total alpha activity of the horizontal sample.

[0009] Specifically, the water treatment component includes: a peristaltic pump, a particle filter and an ultraviolet generator, the input end of the peristaltic pump is connected to the water body, the output end of the peristaltic pump is connected to the input end of the particle filter, the output end of the particle filter pump is connected to the input end of the ultraviolet generator, the output end of the ultraviolet generator is connected to the input end of the γ detector arranged in the first shielding body, the output end of the γ detector is connected to the input end of the β detector arranged in the second shielding body, the output end of the β detector is connected to the input end of the α detector also arranged in the second shielding body, and the output end of the α detector is connected to the water body.

[0010] Furthermore, a flow meter and a pressure gauge are provided at optional positions between the γ detector, the β detector, the α detector and the water treatment component.

[0011] Specifically, a cavity is provided inside the first shielding body, a shielding water tank is provided in the cavity, the γ detector is provided in the shielding water tank, and a water channel inlet and a water channel outlet connected to the inlet and outlet of the γ detector are provided on the first shielding body and the shielding water tank, the water channel inlet is connected to the output end of the water treatment component, and the water channel outlet is connected to the input end of the β detector.

[0012] Optionally, the gamma detector comprises: a main detector and an anti-coincidence detector, the main detector is provided with a central water channel connecting the water channel inlet and the water channel outlet, the anti-coincidence detector is distributed in a ring shape, and the main detector is arranged inside the anti-coincidence detector;

[0013] The main detector is a large-volume NaI detector and a main photomultiplier tube, and the main photomultiplier tube is coupled to the large-volume NaI detector;

[0014] The anti-coincidence detector comprises: a NaI ring crystal array and a first photomultiplier tube, wherein a plurality of the first photomultiplier tubes are respectively coupled with a plurality of scintillation crystals in the NaI ring crystal array.

[0015] Specifically, a β placement cavity is provided inside the second shielding body, and the β detector is arranged in the β placement cavity;

[0016] The β detector comprises: a plastic scintillator plate and a second photomultiplier tube, the two plastic scintillator plates are arranged in parallel, and a β measurement chamber is formed between the inner sides of the two plastic scintillator plates, the input end of the β measurement chamber passes through the β placement cavity and is connected to the output end of the γ detector, and the output end of the β measurement chamber passes through the β placement cavity and is connected to the input end of the α detector;

[0017] The plurality of second photomultiplier tubes are respectively arranged outside the plastic scintillator plate.

[0018] Optionally, the β measurement chamber is sealed on all sides, and the surface of the plastic scintillator plate is covered with a PMMA protective film.

[0019] Specifically, an α placement cavity is provided inside the second shielding body, and the α detector is arranged in the α placement cavity;

[0020] The α detector comprises: a particle scintillator, a light guide support and a third photomultiplier tube, the interior of the light guide support is an α measurement chamber, a plurality of the particle scintillators are distributed in the α measurement chamber, the input end of the α measurement chamber passes through the α placement cavity and is connected to the output end of the β detector, and the output end of the α measurement chamber passes through the α placement cavity and is connected to the water body;

[0021] The plurality of third photomultiplier tubes are respectively arranged on the outer sides of the light guide support member.

[0022] Furthermore, the system also includes a water sample retention component, the output end of the α detector is connected to the water sample retention component and the water body respectively through a three-pronged pipe, and a switch valve is provided at the water inlet of the water sample retention component.

[0023] Optionally, the flow rate of the peristaltic pump is 10 L / min.

[0024] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0025] The water treatment component provided by the present invention is responsible for extracting and processing water samples, so that they pass through various detectors in sequence. The γ detector obtains the γ energy spectrum of the water sample, and the β detector and α detector respectively obtain the β and α total activities of the water sample, thereby realizing accurate detection of different types of radiation.

[0026] The present invention realizes real-time online monitoring of γ, β and α radiation in water bodies, improves the timeliness and accuracy of water radiation pollution detection, and also adopts multi-probe design and physical shielding technology to effectively reduce background radiation interference and ensure low background and high sensitivity of measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The accompanying drawings illustrate exemplary embodiments of the present invention and, together with the description thereof, are used to explain the principles of the present invention. These drawings are included to provide a further understanding of the present invention, and the accompanying drawings are included in and constitute a part of this specification and do not constitute a limitation of the embodiments of the present invention.

[0028] Figure 1 It is a structural schematic diagram of an online measurement system for total radioactivity and nuclides in water according to the present invention.

[0029] Figure 2 It is a schematic diagram of the structure of the gamma detector according to the present invention.

[0030] Figure 3 It is a schematic diagram of the structure of the beta detector according to the present invention.

[0031] Figure 4 It is a schematic diagram of the structure of the α detector according to the present invention.

[0032] Figure 5 Schematic diagram of exciting a plastic scintillator plate by radioactive particles in water according to the present invention.

[0033] Figure 6 It is a schematic diagram of the stimulated luminescence of the particle scintillator according to the present invention.

[0034] Figure 7 The invention provides a mechanism block diagram of a system for online measurement of total radioactivity and nuclides in water.

[0035] Reference numerals: 1-particle filter, 2-ultraviolet generator, 3-flow meter, 4-first shielding body, 5-shielding water tank, 6-γ detector, 7-pressure gauge, 8-second shielding body, 9-β detector, 10-α detector;

[0036] 61 - NaI ring crystal array, 62 - first photomultiplier tube, 91 - plastic scintillator plate, 92 - second photomultiplier tube, 101 - optical guide support, 102 - third photomultiplier tube, 103 - microparticle scintillator. DETAILED DESCRIPTION

[0037] To make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and implementation methods. It is understood that the specific implementation methods described herein are only used to explain the relevant content, rather than to limit the present invention.

[0038] It should also be noted that, for the convenience of description, only the parts related to the present invention are shown in the drawings.

[0039] In the absence of conflict, the embodiments and features of the embodiments of the present invention may be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0040] With the rapid development of nuclear energy and nuclear technology in my country, research on methods and devices that can quickly measure radioactive nuclides in water bodies has become an urgent need in my country's environmental monitoring, especially in nuclear emergency situations. Therefore, uninterrupted environmental monitoring of radioactive nuclides in water bodies is required.

[0041] Total radioactivity and nuclide measurement in water is a low-background measurement technology. Foreign countries started online analysis of total radioactivity and nuclide measurement earlier. Various low-background measurement systems have been developed and applied in large quantities, and relevant research and experimental work has been done. The earliest low-background radioactivity measurement system used a gas-flow proportional counter as a detection element. A typical example is the MPC-9604 low-background counter produced by ORTEC in the United States. It uses a gas-flow proportional counter and the working gas is P10 gas (90% argon and 10% methane gas). It has a simple structure and stable performance. The iMac low-background activity analyzer developed by CANBERRA uses two detection elements, namely the PIPS semiconductor detector and the plastic scintillator detector. The PIPS detector is used to detect α and β particles, and the plastic scintillator detector is used as an anti-coincidence detector to remove the interference of cosmic rays.

[0042] In summary, the detectors used in the low background measurement system include gas detectors (proportional counters), scintillator detectors (mainly composite scintillators combining plastic scintillators and zinc sulfide scintillators), and semiconductor detectors (gold silicon surface barrier detectors, PIPS detectors).

[0043] In order to achieve rapid detection, the international standard proposes the use of liquid scintillator methods to detect and analyze standard water samples, tap water and drinking water. The Institute of Nuclear Sciences at Ankara University in Turkey calculated the minimum detectable concentration (MDC) of total α and total β in accordance with this method and achieved good results. Subsequently, liquid scintillation spectrometry (LSS) was used to simultaneously determine the total α and total β concentrations in drinking water, verifying the effectiveness of this method with good accuracy and precision. LSS technology can be used for rapid screening of samples with excessive radioactive substances and provide a basis for rapid evaluation of the radioactive content of samples. The Polytechnic University of Valencia in Spain mixed water samples and liquid scintillators and measured them with a low background scintillation counter / ultra-low background liquid scintillation spectrometer Quantulus 1220. It can analyze samples with different salt contents and different pH values. This method can complete the assessment of radioactive contamination within 2 hours, and can provide a rapid and accurate response in emergency situations.

[0044] Liquid Scintillation Counter (LSC) can be used to monitor α and β radioactivity in water in a timely manner, but LSC is an offline technology that requires collecting water samples and mixing them with liquid scintillation for measurement, so it is not suitable for real-time monitoring.

[0045] At present, only the European Union has developed a real-time online monitoring system for radioactivity in tap water, which is referred to as TAWARA_RTM. The research team has conducted corresponding research and testing on the performance of the detector and system measurement, and achieved good online analysis results. The TAWARA_RTM system is used to monitor radioactive contamination in water in real time, and can provide timely warning of excessive radioactivity and identification of nuclides. As shown in the figure, the TAWARA_RTM system consists of three parts: an early alarm detector (EAD) for early monitoring of γ radioactivity in water; a real-time monitor (RTM) for continuous monitoring of total α and β in water; and a spectrum detector (SPEC) for identification and quantification of radioactive nuclides. The detector in the RTM uses EJ-444 plastic scintillator. EJ-444 is a ZnS (Ag) phosphor with a thickness of about 20μm deposited on a thin plastic scintillator layer (EJ-212). The ZnS (Ag) layer is used to detect α particles, and the plastic scintillator layer is used to detect β particles. In order to prevent the crystal material from directly contacting water, a PMMA film is coated on the outermost layer of the detector. The EJ-444 plastic scintillator is very thin and almost insensitive to gamma rays.

[0046] Domestic measurement and analysis of total radioactivity is mostly based on the national standard method - thick source method and evaporation concentration method. There are also studies on the use of liquid scintillation for total radioactivity measurement. Overall, the online monitoring and analysis of total radioactivity in water bodies is still relatively backward.

[0047] Some basic research has also been conducted in China on the rapid and timely measurement of α and β radioactivity in water bodies. The University of Science and Technology of China has developed a device for rapid monitoring of radioactive nuclides in water bodies. It uses liquid scintillators and can quickly measure and analyze the α and β nuclides in the target water body in emergencies without the need for a series of treatments such as concentration of water samples, but it cannot measure the total radioactivity. Tsinghua University has designed a set of online monitoring devices for total β in drinking water. The detector of the device is built with 1096 scintillating optical fibers with a length of 50 cm and a diameter of 1 mm. It realizes online continuous measurement of total β, but fails to realize online measurement of α and γ. In recent years, China has successively carried out investigations and studies on the concentration of natural radionuclides in inland water bodies, but the investigation methods are basically fixed-point sampling and laboratory analysis monitoring methods, which will consume a lot of manpower, material and financial resources, and the monitoring results are relatively biased.

[0048] In response to the demand for online measurement and analysis of total radioactivity in water bodies, it is necessary to establish a real-time online measurement system with a thin plastic scintillator array detector as the core to control the background, achieve a better minimum detectable activity index, and realize real-time online measurement and analysis of total radioactivity in water bodies.

[0049] Foreign technology is mature and reliable, and it is at the leading level among similar products, with a high market share, but the price is high. At present, there is no mature and reliable online measurement system for total radioactivity and nuclides in water in China. The functions and performance of similar products in China are in urgent need of development to meet market demand.

[0050] The present invention proposes a monitoring system for continuously monitoring αβγ radioactivity in water, directly performing online measurement on the water body to be measured, quickly measuring and analyzing the total αβγ radioactivity level in the water in real time, giving an over-threshold alarm, grasping the water quality changes in real time, and realizing continuous monitoring of the total radioactivity and nuclides in the water body.

[0051] At present, the technical route of online monitoring abroad (EU TAWARA_RTM) is to use a large-size single detector coated with a micron-level ZnS:Ag luminescent layer to distinguish between α and β particles. It can only measure the total intensity of the nuclide, and cannot identify the nuclide while real-time monitoring. It is necessary to use a separate γ spectrum detector (SPEC) for nuclide identification, which is costly and technically difficult. In addition, the α particle signal cannot be identified after the ZnS:Ag coating is damaged, and the entire detector needs to be replaced, which has the risk of high maintenance costs in the later stage. On the other hand, although the light signals generated by the two luminescent layers have different luminescence peaks and can be used to distinguish the types of particles, there is overlap in the emission spectra, and the crosstalk of the two signals is serious. The accuracy of the measurement is worth discussing, and the system only reduces the γ background by reducing the thickness of the plastic scintillator without further optimization. The liquid scintillator technology route currently used in China can only identify nuclides, and cannot measure the total αβ radiation in real time; the optical fiber technology route can measure the total β online continuously, but cannot achieve online measurement of α.

[0052] Compared with the single-probe αβ activity monitoring, the present invention utilizes the characteristics of the interaction between α and β and matter, and uses a common pipeline multi-probe to measure the two particles separately to achieve spectral isolation. In the lead chamber, NaI (Tl) is used to measure γ rays to distinguish nuclides and corresponding activities. The technology is highly mature, with fast channel response, accurate identification and low crosstalk ratio. Compared with the domestic liquid scintillator and optical fiber technology routes, the present invention can achieve real-time measurement of dynamic flowing water and provide accurate information on the total radioactivity and nuclides of the water body.

[0053] In nature, water is the main medium for transporting radioactive substances. During the decay process, radioactive substances may emit α, β, and γ rays simultaneously. Although the ranges of α and β rays are much smaller than that of γ rays, they have strong ionization capabilities. Once they enter the human body, they will cause internal irradiation to the human body, posing a great threat to physical health. Therefore, radioactive measurement of radionuclides in water bodies is of great significance.

[0054] In the "Classification of Radioactive Wastes" standard, radioactive pollutants are classified into exempt radioactive pollutants, low-level radioactive pollutants (≤4×106 Bq / L), medium-level radioactive wastes (4×106 Bq / L < c ≤ 4×1010 Bq / L), and high-level radioactive pollutants (>4×1010 Bq / L) according to their radioactive activity concentration levels. Since radioactive liquid waste contains a large amount of radionuclides, once it enters the human body through various channels, it will deposit in various organs of the body and cause internal irradiation, which not only affects human health and life but also damages the ecological environment. Therefore, it is necessary to strictly monitor and treat the generated radioactive wastewater to make its concentration meet the corresponding discharge standards before discharging it into the surrounding receiving water bodies.

[0055] The national standard "Hygienic Standard for Drinking Water" (GB5749-2006) stipulates that the guiding values for radioactive indicators in drinking water are a maximum total α activity of 0.5 Bq / L and a maximum total β activity of 1.0 Bq / L. The purpose is to ensure that the annual exposure dose equivalent received by each person is below 0.1 mSv / a when consuming 2 L of water per day; the national standard "Integrated Wastewater Discharge Standard" (GB8978-1996) stipulates that for the discharge of sewage containing radioactive substances, the maximum total α activity is 1.0 Bq / L and the maximum total β activity is 10 Bq / L.

[0056] At present, the construction of water body radioactive monitoring systems in China is not yet perfect. For the monitoring of total α radioactivity and total β radioactivity in inland water bodies and marine water bodies, the commonly used methods are on-site investigation sampling methods and laboratory energy spectrum analysis methods. Among them, laboratory analysis mostly stirs, evaporates, and prepares samples of water samples according to national standard methods, and then uses a low-background αβ measurement device to measure and analyze the total α and total β contents, which requires a lot of manpower and material resources and has a complex procedure. Due to reasons such as long sampling periods, cumbersome operation steps, and poor timeliness of measurement and analysis, these two methods cannot give the total radioactivity and radionuclides of the water body to be measured in real time, making the monitoring results unable to reflect the total αβ radioactivity level of the target water body in real time.

[0057] The present invention can be used in waterworks, sewage treatment plants, hydrological monitoring stations, reservoirs, offshore fishing grounds, industrial facilities discharging wastewater, nuclear power plants, fire departments, and chemical defense forces, etc.

[0058] The online measurement system for total radioactivity and nuclides in water can directly conduct real-time online measurement of the water body to be measured, which can meet the needs of real-time measurement of the water body to be measured on site. It is of great significance to improve the real-time monitoring efficiency of total radioactivity in drinking water and wastewater, and strengthen the total radioactivity and nuclide monitoring of environmental water resources. It has important social value and economic benefits, and has broad application prospects.

[0059] For my country's domestic tap water, industrial medical wastewater, lakes and oceans, a device is needed that can quickly and in real time measure the radioactivity and nuclides in the water to assess the degree and type of radioactive contamination in the water, so as to make a rapid emergency response to radioactive contamination and reduce the losses of the country and the people in accidents.

[0060] Embodiment 1

[0061] like Figure 1 As shown, a system for measuring total radioactivity and nuclides in water on-line includes: a γ detector 6, a β detector 9, an α detector 10 and a water treatment component. The water treatment component extracts water samples and processes them before passing through the γ detector 6, the β detector 9 and the α detector 10. The γ detector 6 is arranged in a first shielding body 4, and the β detector 9 and the α detector 10 are arranged in a second shielding body 8.

[0062] The gamma detector 6 acquires the gamma energy spectrum of the water sample, the beta detector 9 acquires the total beta activity of the horizontal sample, and the alpha detector 10 acquires the total alpha activity of the horizontal sample.

[0063] The water treatment component is first responsible for extracting samples from the water body and performing preliminary treatment on them, such as filtering impurities and eliminating microorganisms. The treated water samples pass through the γ detector 6, β detector 9 and α detector 10 in the system in turn to measure the radioactivity of γ rays, β rays and α rays in the water sample respectively. The γ detector 6 is set in a first shielding body 4 to shield external radiation interference and obtain the γ energy spectrum of the water sample. Energy spectrum refers to the identification and quantitative analysis of the radioactive characteristics of different nuclides in the sample by measuring the energy distribution of γ rays.

[0064] The β detector 9 and the α detector 10 are arranged in a second shielding body 8, which is also used to reduce the influence of external radiation, so as to ensure the accuracy of measurement. The β detector 9 is mainly responsible for measuring the total β activity of the water sample, that is, the overall radioactive intensity of the β particles; while the α detector 10 is used to measure the total α activity, that is, the overall radioactive intensity of the α particles.

[0065] In this embodiment, environmental water samples are extracted to form a circulating water circuit in the system to achieve real-time monitoring. Therefore, the main interference during the detection process is the background generated by the radionuclides in the external water body to the internal detector. In the overall structural design, a shielding body of a certain thickness is required as the outer shell of the measurement chamber to reduce the influence of the nuclides outside the measurement unit. The shielding body is a material used to absorb or block external radiation interference to ensure that the detector only measures radiation from the sample.

[0066] Materials commonly used for shielding bodies include: lead, concrete, steel, polyethylene, tungsten, etc. The shielding body in this embodiment generally refers to one or a combination of these materials.

[0067] In this system, the water treatment component first ensures the purity of the water sample to reduce measurement errors. The gamma detector 6 uses a combination of a photomultiplier tube and a scintillation crystal to obtain the gamma energy spectrum by detecting the photons generated by the interaction between gamma rays and the crystal. The beta and alpha detectors 10 obtain the corresponding total activity data by measuring the interaction between beta particles and alpha particles in the water sample and plastic scintillators or other sensitive materials. The entire system reduces the interference of external background radiation through a shielding body, thereby ensuring the accuracy and sensitivity of the measurement results.

[0068] In order to ensure the purity and provide high-precision and high-sensitivity detection conditions for the online measurement of total radioactivity and nuclides in water, the water treatment component includes: a peristaltic pump, a particle filter 1 and an ultraviolet generator 2, the input end of the peristaltic pump is connected to the water body, the output end of the peristaltic pump is connected to the input end of the particle filter 1, the output end of the particle filter pump is connected to the input end of the ultraviolet generator 2, the output end of the ultraviolet generator 2 is connected to the input end of a γ detector 6 arranged in a first shielding body 4, the output end of the γ detector 6 is connected to the input end of a β detector 9 arranged in a second shielding body 8, the output end of the β detector 9 is connected to the input end of an α detector 10 also arranged in the second shielding body 8, and the output end of the α detector 10 is connected to the water body.

[0069] A flow meter 3 and a pressure gauge 7 are provided at an optional position between the γ detector 6, the β detector 9, the α detector 10 and the water treatment component. The flow meter 3 is used to monitor and control the flow rate of the water sample to ensure that the water sample flows stably throughout the system; the pressure gauge 7 is used to monitor the pressure of the water sample to prevent the measurement accuracy from being affected by pressure fluctuations.

[0070] The peristaltic pump pushes the liquid flow by squeezing the pipe, which has the advantages of not being easy to come into direct contact with the water sample and reducing the risk of contamination. The extracted water sample enters the particle filter 1 through the peristaltic pump to remove the particulate matter in the water sample, and then enters the ultraviolet generator 2 to disinfect and kill algae by emitting ultraviolet rays, further ensuring the cleanliness of the water sample and preventing biological contamination from interfering with subsequent measurements. Under normal circumstances, the flow rate of the peristaltic pump is 10L / min.

[0071] In addition, the system also includes a water sample retention component. The output end of the α detector 10 is connected to the water sample retention component and the water body through a three-pronged pipe, and a switch valve is provided at the water inlet of the water sample retention component.

[0072] By retaining a portion of the water sample for subsequent laboratory analysis or quality control, and because the water sample retention component is directly connected to the α detector 10, the retained water sample can fully represent the sample characteristics measured during the detection process, ensuring the accuracy and consistency of subsequent analysis.

[0073] Embodiment 2

[0074] like Figure 1 and Figure 2 As shown, a cavity is provided inside the first shielding body 4, a shielding water tank 5 is provided in the cavity, a γ detector 6 is provided in the shielding water tank 5, and a water channel inlet and a water channel outlet connected to the inlet and outlet of the γ detector 6 are provided on the first shielding body 4 and the shielding water tank 5, the water channel inlet is connected to the output end of the water treatment component, and the water channel outlet is connected to the input end of the β detector 9.

[0075] The gamma detector 6 includes: a main detector and an anti-coincidence detector, the main detector is provided with a central water channel connecting the water channel inlet and the water channel outlet, the anti-coincidence detector is distributed in a ring shape, and the main detector is arranged inside the anti-coincidence detector;

[0076] The main detector is a large-volume NaI detector and a main photomultiplier tube, and the main photomultiplier tube is coupled to the large-volume NaI detector;

[0077] The anti-coincidence detector includes: a NaI ring crystal array 61 and a first photomultiplier tube 62 . A plurality of first photomultiplier tubes 62 are respectively coupled to a plurality of scintillation crystals in the NaI ring crystal array 61 .

[0078] The nuclear decay signals recorded in the detector include the pulse signals of the sample and the background signals in the environment. The background sources mainly come from three parts: surrounding radioactive nuclides, cosmic rays and electronic noise.

[0079] In order to reduce the background, a combination of physical shielding and anti-coincidence technology is used to shield a part of the gamma rays in the environment through the first shielding body 4 and the shielding water tank 5, shield the surrounding radionuclides and external background light signals, reduce the background of the measurement box as much as possible, and improve the collection efficiency of the fluorescence signal. Some gamma rays will pass through the main detector and deposit energy in the anti-coincidence detector. The anti-coincidence algorithm is used to deduct this part of the gamma rays to achieve the purpose of reducing the background.

[0080] The main detector directly measures the gamma rays in the water sample. It consists of a large NaI (sodium iodide) detector and a main photomultiplier tube coupled to it. The function of the NaI detector is to convert gamma rays into light signals through the scintillation effect, while the main photomultiplier tube further amplifies these light signals and converts them into detectable electrical signals, thereby achieving accurate measurement of gamma rays.

[0081] The anti-coincidence detector is distributed in a ring shape and surrounds the outside of the main detector. It is mainly used to eliminate the interference of environmental gamma rays on the measurement. It consists of a NaI ring crystal array 61 and a plurality of first photomultiplier tubes 62. These photomultiplier tubes are respectively coupled with the scintillation crystals in the NaI ring crystal array 61. When the gamma rays in the environment pass through the main detector and enter the anti-coincidence detector, the anti-coincidence detector will capture this part of the rays and exclude them from the measurement data through the anti-coincidence algorithm, thereby significantly reducing the background noise of the measurement and improving the measurement accuracy of the detector.

[0082] Embodiment 3

[0083] The range of α and β rays is relatively short. In order to achieve online measurement, the detector needs to be placed in the water sample. In order to adapt to different water environments, the selected scintillation crystals need to be non-deliquescent and corrosion-resistant. At the same time, the main detector needs to have the ability to distinguish α and β rays and have good energy resolution.

[0084] like Figure 1 and Figure 3 As shown, a β placement cavity is provided inside the second shielding body 8, and a β detector 9 is provided in the β placement cavity;

[0085] The β detector 9 includes: a plastic scintillator plate 91 and a second photomultiplier tube 92. The two plastic scintillator plates 91 are arranged in parallel, and the inner side surfaces of the two plastic scintillator plates 91 are a β measurement chamber. The input end of the β measurement chamber passes through the β placement cavity and is connected to the output end of the γ detector 6. The output end of the β measurement chamber passes through the β placement cavity and is connected to the input end of the α detector 10.

[0086] A plurality of second photomultiplier tubes 92 are respectively arranged outside the plastic scintillator plate 91. The photomultiplier tubes in this embodiment are silicon photomultiplier tubes (SiPM).

[0087] The β measurement chamber is sealed all around, and the surface of the plastic scintillator plate 91 is covered with a PMMA protective film.

[0088] The β detector 9 is composed of two parallel plastic scintillator plates 91 and a plurality of second photomultiplier tubes 92. A β measurement chamber is formed between the two plastic scintillator plates 91, and the measurement chamber is used to measure the β radioactivity of the water sample. The surface of the plastic scintillator plate 91 is covered with a layer of PMMA protective film, which is mainly used to prevent the chemical substances in the water sample from corroding the scintillator plate, prolong the service life of the detector, and ensure the stability and accuracy of the measurement.

[0089] When the water sample flows in the β measurement chamber, the β particles interact with the plastic scintillator to generate photon signals, which are collected and amplified by multiple second photomultiplier tubes 92 arranged outside the plastic scintillator plate 91 and finally converted into electrical signals for subsequent analysis.

[0090] Embodiment 4

[0091] An α placement cavity is provided inside the second shielding body 8, and the α detector 10 is provided in the α placement cavity;

[0092] Since the α particles have a short range and lose energy quickly in the material, the α detector 10 includes: a particle scintillator, a light guide support 101 and a third photomultiplier tube 102. The interior of the light guide support 101 is an α measurement chamber, and a plurality of particle scintillators are distributed in the α measurement chamber. The input end of the α measurement chamber passes through the α placement cavity and is connected to the output end of the β detector 9. The output end of the α measurement chamber passes through the α placement cavity and is connected to the water body.

[0093] A plurality of third photomultiplier tubes 102 are respectively disposed outside the light guide support 101 .

[0094] An α measurement chamber is formed inside the optical support 101, and a plurality of micro-scintillators are evenly distributed in the α measurement chamber. Micro-scintillators are materials that can interact with α particles. When α particles pass through, the scintillators emit light signals. These light signals pass through the light-transmitting optical support 101 and are received by the third photomultiplier tube 102, which converts these signals into electrical signals.

[0095] Particle scintillator is a scintillation material composed of tiny particles, which is used to detect high-energy particles such as alpha particles and has high sensitivity and response speed.

[0096] The light guide support 101 is usually made of optical fiber or other highly light-transmitting materials to ensure that the optical signal can be effectively transmitted to the photomultiplier tube.

[0097] Embodiment 5

[0098] Provide a specific example.

[0099] The detector parameters are as follows:

[0100] β detector: contains 2 plastic scintillator plates, with a size of 500mm*500mm*0.3mm, and is equipped with a high-performance silicon photomultiplier tube (SiPM);

[0101] α detector: micro-scintillator (filled in a measuring chamber with a thickness of 20 mm), equipped with a high-performance silicon photomultiplier tube (SiPM);

[0102] Gamma detector: 6 groups of NaI scintillators (φ25mm H40mm) annular crystals and photomultiplier tube arrays.

[0103] Radiation detection performance is as follows:

[0104] Background counting pass rate: ≥250kcps;

[0105] Energy resolution and energy range: The energy resolution of the NaI gamma online spectrometer is better than 4% (for 662keV of Cs-137), and it measures gamma rays with energies of 200keV-3MeV. Depending on different detection locations, the following nuclides can be selected for monitoring: Co-58, Co-60, Mn-54, Sb-124, Cs-137, I-131, Bi-214, Tl-208, K-40, etc.

[0106] Crosstalk ratio: α to β: less than 10%; β to α: less than 2%;

[0107] Minimum detectable activity concentration (MDAC) detection limit: (12 hours)

[0108] γ: less than 0.2Bq / L 137Cs;

[0109] α: less than 0.05Bq / L;

[0110] β: less than 0.5Bq / L;

[0111] Response speed: 15min alarm, total α alarm limit is 0.5Bq / L; total β alarm limit is 1Bq / L;

[0112] Electrical characteristics: The main power supply is 220V (±10%), 50 / 60Hz; the backup power supply is an online UPS, and the power supply time is not less than 0.5h;

[0113] Environmental adaptability: working temperature: -0℃~+50℃; storage temperature: -10℃~+60℃; humidity: 10%-95%.

[0114] Mechanical properties: Total weight: excluding test water sample: ≯500kg; Overall dimensions (length × width × height): ≯(1300±5)mm×(800±5)mm×(1200±5)mm.

[0115] The system is installed on the water inlet pipe and continuously monitors the total radioactivity and nuclides in the drainage of the entire facility 24 hours a day. The detector is designed to be easy to replace.

[0116] Embodiment 6

[0117] like Figure 7 As shown, the online measurement system for total radioactivity and nuclides in water of the present invention realizes efficient identification of multiple nuclides in water and accurate measurement of radioactivity through a series of advanced algorithms and hardware designs. The key steps of system operation include initial value verification calculation, structural characterization correction, composite measurement channel sampling, energy resolution counting statistics, energy spectrum deconvolution, multi-nuclide identification, etc.

[0118] Initial value verification calculation and structural characterization correction are the basic steps of the system, which are used to calibrate and verify the initial parameters and structural characteristics of the detector to ensure the accuracy of subsequent measurements.

[0119] During the sampling process, the system adopted a composite measurement channel sampling method to fully capture the radiation information in the water sample through multi-probe measurements. Subsequently, the system performed energy-resolved counting statistics, in which the interval multi-pulse clustering algorithm and energy spectrum deconvolution algorithm based on FPGA were applied. These algorithms significantly improved the energy resolution and reduced the measurement error through the fine analysis and processing of the measurement signal, ensuring the accurate identification of different rays (α, β, γ).

[0120] The interval multi-pulse clustering algorithm consists of an interval seed averaging algorithm and a digital multiplication technique. The interval seed averaging algorithm implements a selective method for statistical analysis in a narrow pulse amplitude window. When the first pulse height is measured, it creates a statistical range based on the statistical window. When the second pulse amplitude within the statistical range is measured, the two pulse amplitudes are averaged, and the center of the statistical range is moved to the calculated average value, and so on, until the predetermined number of statistical pulse amplitudes is reached, and the amplitude average of the pulses is extracted as the pulse amplitude.

[0121] Certain αβ rays of energy in water will cause the detector to record repeatedly, so it is necessary to distinguish αβ. The study of algorithm analysis of multi-probe measurement can realize the accurate measurement of total α activity concentration and total β activity concentration. According to the different luminescence decay time of α, β, and γ rays in the scintillation crystal, the different shapes of the generated pulses, and the difference in the amplitude of the two pulses, the pulse discrimination technology is used to discriminate the two pulses. The α, β, and γ pulses are collected by an oscilloscope, and the effects of different discrimination algorithms are calculated in Matlab. The optimal algorithm is selected and implemented in FPGA to judge the decay of different types of rays.

[0122] Rays with similar energies also have overlapping peaks, forming a complex energy spectrum, and it is necessary to study the identification and analysis technology of multiple nuclides in gamma spectrum analysis. The information extraction and recognition technology of artificial neural networks is studied, and artificial neural networks are applied to the rapid identification and processing of nuclides. Combined with spectrum analysis methods, the rapid identification and analysis of multiple nuclides based on NaI gamma spectrometer is realized.

[0123] Finally, the system automatically analyzes the total activity of multiple nuclides for all measurement data, combines multiple measurement parameters, and automatically generates a water body radioactivity concentration report. At the same time, the system has early warning-alarm and online recording remote monitoring functions, which can automatically issue an alarm when the water body radioactivity exceeds the standard, and supports remote data access and real-time monitoring.

[0124] In the description of this specification, the description with reference to the terms "one embodiment / method", "some embodiments / methods", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment / method or example are included in at least one embodiment / method or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment / method or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments / methods or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments / methods or examples described in this specification and the features of the different embodiments / methods or examples, unless they are contradictory.

[0125] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0126] It should be understood by those skilled in the art that the above embodiments are only for the purpose of clearly illustrating the present invention, and are not intended to limit the scope of the present invention. For those skilled in the art, other changes or modifications may be made based on the above invention, and these changes or modifications are still within the scope of the present invention.

Claims

1. A system for measuring total radioactivity and nuclides in water, characterized in that: include: A gamma detector (6), a beta detector (9), an alpha detector (10) and a water treatment component, wherein the water treatment component extracts a water sample and processes the water sample before passing through the gamma detector (6), the beta detector (9) and the alpha detector (10), wherein the gamma detector (6) is arranged in a first shielding body (4), and the beta detector (9) and the alpha detector (10) are arranged in a second shielding body (8); The gamma detector (6) acquires the gamma energy spectrum of the water sample, the beta detector (9) acquires the total beta activity of the horizontal sample, and the alpha detector (10) acquires the total alpha activity of the horizontal sample.

2. The online measurement system for total radioactivity and nuclides in water according to claim 1 is characterized in that: The water treatment component comprises: a peristaltic pump, a particle filter (1) and an ultraviolet generator (2); the input end of the peristaltic pump is connected to a water body; the output end of the peristaltic pump is communicated with the input end of the particle filter (1); the output end of the particle filter pump is communicated with the input end of the ultraviolet generator (2); the output end of the ultraviolet generator (2) is communicated with the input end of the gamma detector (6) arranged in the first shielding body (4); the output end of the gamma detector (6) is communicated with the input end of the beta detector (9) arranged in the second shielding body (8); the output end of the beta detector (9) is communicated with the input end of the alpha detector (10) also arranged in the second shielding body (8); and the output end of the alpha detector (10) is connected to the water body.

3. The online measurement system for total radioactivity and nuclides in water according to claim 1 is characterized in that: A flow meter (3) and a pressure gauge (7) are provided at an optional position between the gamma detector (6), the beta detector (9), the alpha detector (10) and the water treatment component.

4. The online measurement system for total radioactivity and nuclides in water according to claim 1 is characterized in that: A cavity is provided inside the first shielding body (4), a shielding water tank (5) is provided in the cavity, the gamma detector (6) is provided in the shielding water tank (5), and a waterway inlet and a waterway outlet connected to the inlet and outlet of the gamma detector (6) are provided on the first shielding body (4) and the shielding water tank (5), the waterway inlet is connected to the output end of the water treatment component, and the waterway outlet is connected to the input end of the beta detector (9).

5. The system for online measurement of total radioactivity and nuclides in water according to claim 4, characterized in that: The gamma detector (6) comprises: a main detector and an anti-coincidence detector, the main detector is provided with a central water channel connecting the water channel inlet and the water channel outlet, the anti-coincidence detector is distributed in a ring shape, and the main detector is arranged inside the anti-coincidence detector; The main detector is a large-volume NaI detector and a main photomultiplier tube, and the main photomultiplier tube is coupled to the large-volume NaI detector; The anti-coincidence detector comprises: a NaI ring crystal array (61) and a first photomultiplier tube (62); a plurality of the first photomultiplier tubes (62) are respectively coupled to a plurality of scintillation crystals in the NaI ring crystal array (61).

6. The online measurement system for total radioactivity and nuclides in water according to claim 1, characterized in that: A β placement cavity is arranged inside the second shielding body (8), and the β detector (9) is arranged in the β placement cavity; The β detector (9) comprises: a plastic scintillator plate (91) and a second photomultiplier tube (92); the two plastic scintillator plates (91) are arranged in parallel, and a β measurement chamber is provided between the inner sides of the two plastic scintillator plates (91); the input end of the β measurement chamber passes through the β placement cavity and is connected to the output end of the γ detector (6); and the output end of the β measurement chamber passes through the β placement cavity and is connected to the input end of the α detector (10); A plurality of the second photomultiplier tubes (92) are respectively arranged outside the plastic scintillator plate (91).

7. The online measurement system for total radioactivity and nuclides in water according to claim 6, characterized in that: The β measurement chamber is sealed on all sides, and the surface of the plastic scintillator plate (91) is covered with a PMMA protective film.

8. The online measurement system for total radioactivity and nuclides in water according to claim 1, characterized in that: An α placement cavity is arranged inside the second shielding body (8), and the α detector (10) is arranged in the α placement cavity; The α detector (10) comprises: a particle scintillator, a light guide support (101) and a third photomultiplier tube (102); the interior of the light guide support (101) is an α measurement chamber; a plurality of the particle scintillators are distributed in the α measurement chamber; the input end of the α measurement chamber passes through the α placement cavity and is connected to the output end of the β detector (9); the output end of the α measurement chamber passes through the α placement cavity and is connected to a water body; The plurality of third photomultiplier tubes (102) are respectively arranged outside the light guide support member (101).

9. The online measurement system for total radioactivity and nuclides in water according to claim 2, characterized in that: It also comprises a water sample retention component, wherein the output end of the α detector (10) is respectively connected to the water sample retention component and the water body through a three-pronged pipe, and a switch valve is arranged at the water inlet of the water sample retention component.

10. The online measurement system for total radioactivity and nuclides in water according to claim 2, characterized in that: The flow rate of the peristaltic pump is 10 L / min.

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