On-site measuring device for uranium in water

Abstract

The utility model relates to the technical field of uranium activity and concentration measurement in water, in particular to a field measurement device for uranium in water. Comprising a flow sampling unit, a detection unit, a signal acquisition and processing unit, a display unit and a power supply module. The power supply module supplies power to the flow sampling unit, the detection unit, the signal acquisition and processing unit and the display unit, the flow sampling unit is connected with the detection unit, the detection unit is connected with the signal acquisition and processing unit, and the signal acquisition and processing unit is connected with the display unit. The device is convenient to carry and low in power consumption, and can be used for rapidly measuring the uranium content in the wastewater field; according to the device, sample pretreatment is not needed, and on-site and rapid measurement of a sample can be realized; the device adopts a flow injection analysis technology to control the automatic pumping of a sample and the flow velocity and volume of the sample; the device breaks through the field measurement technology of short-range alpha particles in water, and realizes the field rapid measurement of the uranium content in the radioactive wastewater by establishing the mapping relation between the radioactive nuclide uranium content of the enrichment scintillation sensor and the radioactive nuclide content in water.

Description

Technical Field

[0001] The utility model relates to the technical field of measuring uranium activity concentration in water, in particular to a device for measuring uranium on-site in water. Background Art

[0002] my country started early in the analysis and research of uranium content in water. In the late 1970s and early 1980s, a large amount of research work was carried out. In 1989, the State Environmental Protection Administration promulgated a series of standards that have continued to this day, which regulate the analysis methods, analysis processes and measurement ranges of uranium radionuclides in water. The standard analysis methods for trace uranium in water mainly include non-radioactive liquid laser fluorescence and spectrophotometry. In addition, commonly used non-radioactive analysis methods include volumetric analysis, isotope dilution mass spectrometry (ID-MS), inductively coupled plasma spectroscopy (ICP-MS) and isotope dilution inductively coupled plasma mass spectrometry (ID-ICP-MS). Radioactive methods include α spectroscopy, γ spectroscopy, and liquid scintillation counting. Except for the liquid laser fluorescence method, which can directly determine the uranium content, all other types of analysis methods require sample pretreatment (separation and enrichment, etc.) before determination.

[0003] Although the automation and miniaturization of all aspects of radiochemical analysis in my country have been greatly developed under the premise of maintaining or reducing the existing detection limit, simplifying the analysis process and greatly shortening the analysis time, these improvements are limited to laboratory analysis, and there are no reports on their application to rapid on-site measurements. Therefore, simply improving the speed of laboratory analysis and shortening the laboratory analysis process cannot fundamentally meet all routine monitoring needs. In abnormal situations, especially accidents, it is impossible to quickly obtain the activity concentration of key nuclides in water on-site, which seriously affects the timeliness, pertinence and effectiveness of radiation protection for emergency workers. It is imperative to establish a method that can conveniently and quickly measure the uranium content in water on-site. Utility Model Content

[0004] The main purpose of the utility model is to provide an on-site measurement device for uranium in water, which can effectively simplify the sample collection, manual transportation, sample pre-treatment, source preparation, measurement and other links in the traditional sampling and monitoring process, and solve the problems of cumbersome sampling and monitoring procedures, long process cycles, and low timeliness of measurement results. In abnormal situations, especially accidents, the activity concentration of key nuclides in water can be quickly identified on-site (on-site), which improves the timeliness, pertinence and effectiveness of radiation protection for emergency workers.

[0005] The technical solution of the utility model is as follows: an in-water uranium field measurement device, comprising a flow sampling unit, a detection unit, a signal acquisition and processing unit, a display unit and a power module. The power module supplies power to the flow sampling unit, the detection unit, the signal acquisition and processing unit and the display unit, the flow sampling unit is connected to the detection unit, the detection unit is connected to the signal acquisition and processing unit, and the signal acquisition and processing unit is connected to the display unit.

[0006] The flow sampling unit includes a solenoid valve, a peristaltic pump, a three-way valve, a connecting pipeline, and a seal. The two ports of the three-way valve are connected to the pipeline to form two sample inlets, and the middle port is connected to the pipeline to form a sample outlet. There is a solenoid valve in the middle of the connecting pipeline forming the sample inlet, and there is a peristaltic pump in the gap between the two sample inlets and the sample outlet.

[0007] The flow sampling unit is externally wrapped by a shell, and three flow regulating buttons are arranged on the upper part of the shell to respectively adjust the flow of two sample inlets and one sample outlet, and a sealing member is arranged on the upper part of the sample outlet.

[0008] The solenoid valve is a direct-acting solenoid valve, and the valve body is made of brass; the peristaltic pump is a speed-regulating peristaltic pump, model BT01-DG-2, wherein the pump head model is DG-2, the driver model is BT01, and the flow adjustment range is 0.02-20mL / min.

[0009] The detection unit comprises an enrichment scintillation sensor, and two ends of the enrichment scintillation sensor are connected to photomultiplier tubes.

[0010] The signal acquisition and processing unit includes a data acquisition system and a data processing system, and the data acquisition system and the data processing system include an analog-to-digital conversion circuit, an FPGA signal processing module, and a signal transmission module;

[0011] After receiving the current signal, the analog-to-digital conversion circuit transmits it to the positive / negative polarity selection circuit in the measurement room, and is converted into a digital signal after pole-zero cancellation, attenuation control, gain control, baseline adjustment and analog-to-digital conversion, and is transmitted to the FPGA signal processing module. The FPGA signal processing module includes a nuclear pulse signal processing part and an embedded system. The nuclear pulse signal processing part completes ADC data acquisition, baseline recovery, fast pulse shaping, trapezoidal shaping, and amplitude spectrum synthesis, and sends the amplitude spectrum data or ADC data to the embedded system. The embedded system is the CPU of the measurement system, which completes interface control, data interaction with the display unit or PC client, data interaction with the signal processing module, and analog circuit control; after the signal transmission module processes the radiation signal input from the measurement room, it uploads it to the display unit or host computer for display by wired or wireless means.

[0012] The beneficial effects of the utility model are as follows: the device is easy to carry, has low power consumption, and can be used for rapid measurement of uranium content in wastewater on site; the device does not require sample pretreatment and can achieve on-site and rapid measurement of samples; the device adopts flow injection analysis technology to control automatic pumping of samples, flow rate and volume of samples; the device breaks through the on-site measurement technology of short-range alpha particles in water, and achieves rapid on-site measurement of uranium content in radioactive wastewater by establishing a mapping relationship between the uranium content of radioactive nuclides in enriched scintillation sensors and the content of radioactive nuclides in water. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 A diagram showing the composition of a device for measuring uranium in water on site provided by the utility model;

[0014] Figure 2 It is the structure diagram of the flow unit;

[0015] Figure 3 is a signal processing flow chart;

[0016] Figure 4 It is the FPGA signal processing module;

[0017] Figure 5 This is the block diagram of the power module.

[0018] In the figure: 14 injection port, 15 flow adjustment button, 16 outlet port, 17 sealing member, 18 pipeline, 19 solenoid valve, 20 peristaltic pump, 21 housing, 22 three-way valve. DETAILED DESCRIPTION

[0019] The utility model is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0020] like Figure 1 As shown, a device for measuring uranium in water on-site comprises a flow sampling unit, a detection unit, a signal acquisition and processing unit, a display unit and a power module. The power module supplies power to the flow sampling unit, the detection unit, the signal acquisition and processing unit and the display unit. The flow sampling unit is connected to the detection unit, the detection unit is connected to the signal acquisition and processing unit, and the signal acquisition and processing unit is connected to the display unit.

[0021] In some embodiments, Figure 2As shown, the flow sampling unit includes a solenoid valve 19, a peristaltic pump 20, a three-way valve 22, a connecting pipeline 18, and a sealing member 17. The peristaltic pump 20 includes a pump head, a driver, and an elastic hose. The two ports of the three-way valve 22 are connected to the pipeline 18 to form two sample inlets 14, and the middle port is connected to the pipeline 18 to form a sample outlet 16. There is a solenoid valve 19 in the middle of the connecting pipeline 18 forming the sample inlet 14, and there is a peristaltic pump 20 in the gap between the two sample inlets 14 and the sample outlet 16. The outside of the flow sampling unit is wrapped by a shell 21, and there are three flow adjustment buttons 15 on the upper part of the shell 21, which respectively adjust the flow of the two sample inlets and one sample outlet, and a sealing member 17 is provided on the upper part of the sample outlet 16.

[0022] Among them, the solenoid valve 19 is an automated basic component used to control the fluid. It is an actuator that can cooperate with different circuits to control the direction, flow, speed and other parameters of the medium, and has high control accuracy. When the power is turned on, the electromagnetic coil generates electromagnetic force to lift the closing piece from the valve seat, and the valve opens; when the power is turned off, the electromagnetic force disappears, the spring presses the closing piece on the valve seat, and the valve closes. The peristaltic pump 20 pumps water samples by alternately squeezing and releasing the elastic hose of the pump, and its flow rate is determined by the diameter of the tube and the compression speed.

[0023] In some embodiments, the solenoid valve 19 adopts a direct-acting solenoid valve (6606 type liquid solenoid valve), and the valve body is made of brass. The seal is made of PEEK material, which is acid-resistant and alkali-resistant, and has a small dead volume (about 30 μL). The peristaltic pump 20 adopts a speed-regulating peristaltic pump, model BT01-DG-2, in which the pump head model is DG-2, the driver model is BT01, and the flow adjustment range is 0.02-20 mL / min.

[0024] As the sample input part of the whole device, the flow sampling unit mainly consists of a sequential injection system based on flow injection analysis technology. The main functions are: automatically start or stop pumping water samples, filling and discharging water samples into the enrichment scintillation sensor. Key parameters, such as pipe size, pump flow rate, etc., need to be determined according to the enrichment efficiency of the material in the enrichment scintillation sensor and the expected target of the detection limit of the measurement device. In addition, for water samples with complex matrices, this unit also includes a filtration device to filter out some interfering impurities.

[0025] In some embodiments, the detection unit includes a photomultiplier tube connected to both ends of the enriched scintillation sensor. The photomultiplier tube is a functional element that converts a fluorescent signal into a current signal. The front end face of the photomultiplier tube is connected to the enriched scintillation sensor, and the rear end is connected to the signal acquisition and processing unit. The outer side of the photomultiplier tube is made of Permalloy material, which can reduce the impact of external electromagnetic interference and natural background on the photomultiplier tube. The alloy is a black sealed stainless steel outer cylinder to shield external visible light. The photomultiplier tube adopts the CR105-3 type produced by Hamamatsu Corporation.

[0026] In some embodiments, the signal acquisition and processing unit includes a data acquisition system and a data processing system. The data acquisition system uses FPGA (Field Programmable Gate Array) as the core controller, designs a data acquisition module, controls the analog digital converter (ADC) to perform data sampling, and stores the sampled data in an SRAM memory to achieve the function of data acquisition and storage. The data processing system uses DSP (Digital signal processing) as the core controller.

[0027] like Figure 3 and Figure 4 As shown, the data acquisition system and the data processing system include an analog-to-digital conversion circuit, an FPGA signal processing module, and a signal transmission module.

[0028] After receiving the current signal, the analog-to-digital conversion circuit transmits it to the positive / negative polarity selection circuit in the measurement room, and after pole-zero cancellation, attenuation control, gain control, baseline adjustment and analog-to-digital conversion, it is converted into a digital signal and transmitted to the FPGA signal processing module. The FPGA signal processing module is the most critical module for digital multi-channel, including the nuclear pulse signal processing part and the embedded system. The nuclear pulse signal processing part completes ADC data acquisition, baseline recovery, fast pulse shaping, trapezoidal shaping, and amplitude spectrum synthesis, and sends the amplitude spectrum data or ADC data to the embedded system. The embedded system is the CPU of the measurement system, which completes interface control (including USB, RJ45, RS232, status indication, etc.), data interaction with the display unit or PC client, data interaction with the signal processing module, and analog circuit control.

[0029] In some embodiments, the embedded system uses a ucos II embedded system.

[0030] The signal transmission module processes the radiation signal input from the measurement room and uploads it to the display unit or host computer for display via wired or wireless means.

[0031] In some embodiments, the signal transmission module interface includes three interfaces: USB, RJ45 and RS232. Among them, the USB interface communicates with the FPGA via the SPI serial bus. The USB2.0 protocol processing is completed inside the chip, which reduces the workload of the embedded system and improves the system stability. The RJ45 network interface uses the DM9000 interface chip to complete the conversion between network data and the parallel bus, and communicates with the FPGA via the parallel bus. The TCP / IP protocol stack is processed by the embedded system. There are 2 RS232 interfaces, which are mainly used for debugging and system diagnosis, one for the embedded system and the other for the FPGA.

[0032] The signal acquisition and processing unit is a functional module that converts current signals into counts. After being amplified, the current signal is sent to the high-speed ADC for processing and converted into counts after FPGA spectrum analysis and calculation.

[0033] In some embodiments, for positive / negative polarity pulse signal input, the polarity of the input pulse signal is selected by the PC software, and the input analog channel is selected by the FPGA. For pole-zero cancellation, the pulse width of the input pulse signal is ≤50us, and the pulse signal is differentiated to narrow the pulse width and improve the signal pass rate; in order to make the trapezoidal flat top flat after forming, a variable resistor is introduced to adjust the overshoot; the display unit provides an oscilloscope function, and the conditioned pulse signal can be directly observed; by setting the variable resistor parameters on the display unit, the variable resistor is adjusted through FPGA control to achieve pole-zero cancellation. For attenuation control, since the amplitude range of the input pulse signal is ±5V / ±10V, and the differential signal range of the ADC is 2Vppm, the input pulse signal needs to be attenuated, and the attenuation circuit is also implemented by selecting parameters on the PC or through FPGA control. For baseline adjustment, the baseline needs to be adjusted before the pulse signal is sent to the ADC to match the differential input range of the ADC [-1,1]V, accompanied by an active first-order low-pass filter (anti-aliasing filter) function. For ADC, AD9245-60M, 14 bits, theoretical channel address is 16K, actual channel address is 1024 channels.

[0034] In this embodiment, preferably, the display unit mainly includes a power supply and an operation display module, and the whole is made of aluminum alloy. The basic functions of the display unit include: a. Receive the counting rate information of the detection unit through the RS485 cable; b. Complete the human-computer interaction function; c. Realize communication with the detector, and have the display and storage of data; d. Can set 4 levels of alarm, when the concentration level exceeds the set alarm threshold, trigger the sound and light alarm; e. Alarm sound: 85 decibels at 1 meter; f. The parameters of the instrument can be modified, imported and exported, and the instrument operation mode can be switched; g. It has a self-diagnosis function, self-checks when turned on, and monitors the various states of the instrument operation in real time during operation. Specific fault information can be obtained through maintenance software; h. The instrument displays and outputs measurement values: measurement time, water sample volume, activity concentration value, counting rate, status information and alarm information; i. The instrument has the function of recording the operation status (including faults, operations, alarms, etc.); j. It has a historical query function and an export function; k. Supports authority management; l. Protection level: IP55.

[0035] like Figure 5 As shown, the display unit mainly completes the input parameter setting and the display and analysis functions of the measurement results, receives the counting rate information transmitted by RS485 and completes the functions of human-computer interaction and display.

[0036] The measurement parameters mainly control the operation of the detector and obtain the measurement results, including measurement time, working high voltage, threshold setting, and data saving method. The above parameters are set by the user through the process of the form module. The data saving methods include automatic saving and hourly saving. Automatic saving is determined by the measurement time. When saving at the hour, the data acquisition time should be greater than 3600s.

[0037] In some embodiments, the power module is powered by external DC. The power module is divided into two paths. One path steps down the input DC to 13VA through TPS54332 DC / DC, and then transfers out +12VA and +3VA through two TPS73801 LDOs, which are respectively supplied to the high-voltage module input, detection unit and ADC. The other path steps down the input DC to +3.3VD through TPS54332 DC / DC, and then transfers out +1.2VD through MIC49300 for FPGA and digital circuits. In addition, MAX766 is used to boost +3.3VD to -13V, and then UCC384 is used to transfer out -12VA for the probe.

[0038] In this embodiment, preferably, the housing of the in-water uranium on-site measuring device is made of black aluminum alloy.

[0039] The utility model is a field measuring device for uranium in water. When the measuring device is used, the flow sampling unit quantitatively pumps the uranium-containing solution into the detection unit, the detection unit completes the enrichment and scintillation of uranium, and converts the α particles generated by uranium decay into current signals. The current signals are processed, analog-to-digital converted, spectrum processed, etc. in the signal acquisition and processing unit to convert them into counting rates, and then displayed in the display unit. The measurement results are displayed in real time and automatically saved, the radioactivity level of the water sample is evaluated according to the measurement results, and a warning signal of abnormal or excessive radioactivity is provided.

Claims

1. A device for measuring uranium in water on site, characterized in that: It includes a flow sampling unit, a detection unit, a signal acquisition and processing unit, a display unit and a power module, wherein the power module supplies power to the flow sampling unit, the detection unit, the signal acquisition and processing unit and the display unit, the flow sampling unit is connected to the detection unit, the detection unit is connected to the signal acquisition and processing unit, and the signal acquisition and processing unit is connected to the display unit; The flow sampling unit comprises a solenoid valve, a peristaltic pump, a three-way valve, a connecting pipeline and a sealing member. The two ports of the three-way valve are connected to the pipeline to form two sample inlets, the middle port is connected to the pipeline to form a sample outlet, and the middle part of the connecting pipeline forming the sample inlet is provided with a solenoid valve, and the gap between the two sample inlets and the sample outlet is provided with a peristaltic pump. The detection unit comprises an enrichment scintillation sensor, and both ends of the enrichment scintillation sensor are connected to photomultiplier tubes; The signal acquisition and processing unit includes a data acquisition system and a data processing system, and the data acquisition system and the data processing system include an analog-to-digital conversion circuit, an FPGA signal processing module, and a signal transmission module; After receiving the current signal, the analog-to-digital conversion circuit transmits it to the positive / negative polarity selection circuit in the measurement room, and is converted into a digital signal after pole-zero cancellation, attenuation control, gain control, baseline adjustment and analog-to-digital conversion, and is transmitted to the FPGA signal processing module. The FPGA signal processing module includes a nuclear pulse signal processing part and an embedded system. The nuclear pulse signal processing part completes ADC data acquisition, baseline recovery, fast pulse shaping, trapezoidal shaping, and amplitude spectrum synthesis, and sends the amplitude spectrum data or ADC data to the embedded system. The embedded system is the CPU of the measurement system, which completes interface control, data interaction with the display unit or PC client, data interaction with the signal processing module, and analog circuit control; after the signal transmission module processes the radiation signal input from the measurement room, it uploads it to the display unit or host computer for display by wired or wireless means.

2. A device for measuring uranium in water on-site as claimed in claim 1, characterized in that: The flow sampling unit is externally wrapped by a shell, and three flow regulating buttons are arranged on the upper part of the shell to respectively adjust the flow of two sample inlets and one sample outlet, and a sealing member is arranged on the upper part of the sample outlet.

3. The on-site measuring device for uranium in water according to claim 1, characterized in that: The solenoid valve is a direct-acting solenoid valve, and the valve body is made of brass; the peristaltic pump is a speed-regulating peristaltic pump, model BT01-DG-2, wherein the pump head model is DG-2, the driver model is BT01, and the flow adjustment range is 0.02-20mL / min.

Images