Nuclide Retention Measurement System and Measurement Method

Abstract

The present application relates to a nuclide retention measurement system and a measurement method. The nuclide retention measurement system includes: a moving device that can move along a first direction; a rotating device disposed on the moving device, the rotation axis of the rotating device extends along a second direction, and can move along the first direction with the moving device; a semiconductor detection device connected to the rotating device and capable of rotating with the rotating device, the semiconductor detection device includes a probe, and the probe is used to detect the energy peak and net peak area of the nuclide with a geometric shape in the target object; a ranging module connected to the probe for measuring the distance between the probe and the nuclide; an electronic control unit electrically connected to the semiconductor detection device and the ranging module, and the electronic control unit establishes an analysis model according to the geometric shape of the nuclide retention and the distance between the probe and the nuclide, calculates the detection efficiency corresponding to different energy peaks, so as to obtain the composition and mass of the nuclide retention. The present application can achieve quantitative measurement of the nuclide retention amount.

Description

Technical Field

[0001] The present invention relates to the technical field of radionuclides, and particularly to a nuclide retention measurement system and a measurement method. Background Art

[0002] With the process of economic globalization and the increasing complexity of the international security situation, the risks of illegally obtaining, smuggling, trafficking in radionuclides, and even manufacturing nuclear terrorist incidents are increasing worldwide, and the safety work of radionuclides cannot be ignored.

[0003] In order to prevent the theft, damage, loss, illegal transfer, and illegal use of radionuclides, it is necessary to manage the quantity of radionuclides in a specified area and the changes in quantity within a specified time, which requires the establishment of means such as radionuclide accounting and control. There are residues and dissolution liquids of some materials deposited in certain links of the nuclear fuel cycle production process, and the retention formed during the dissolution stage becomes an important factor affecting the radionuclide production accounting. It is necessary to accurately measure the retention. The unknown loss of radionuclides generally exists in the retention of radionuclides. The measurement of radionuclide retention is of great significance for radionuclide recovery, accounting, safe operation of facilities, equipment decontamination, and decommissioning. Summary of the Invention

[0004] The object of the present invention is to provide a nuclide retention measurement system and a measurement method, and the nuclide retention measurement system can quantitatively measure the components and mass of the nuclide retention.

[0005] To this end, the present invention provides a nuclide retention measurement system, including: a moving device that can move along a first direction; a rotating device disposed on the moving device, the rotation axis of the rotating device extends along a second direction, and can move along the first direction with the moving device, and the first direction and the second direction are intersectingly arranged; a semiconductor detection device connected to the rotating device and capable of rotating with the rotating device, the semiconductor detection device includes a probe, and the probe is used to detect the energy peaks and net peak areas of nuclides with geometric shapes in a target object; a ranging module connected to the probe for measuring the distance between the probe and the nuclide; an electronic control unit electrically connected to the semiconductor detection device and the ranging module, and the electronic control unit establishes an analysis model according to the geometric shape of the nuclide retention and the distance between the probe and the nuclide, calculates the detection efficiency corresponding to different energy peaks, so as to obtain the components and mass of the nuclide retention.

[0006] According to one aspect of the present invention, the semiconductor detection device is a high-purity germanium detector, and the semiconductor detection device further includes a storage tank connected to the probe, and the storage tank is used to store liquid nitrogen.

[0007] According to one aspect of the present invention, it further includes an inflation device for supplying liquid nitrogen to the storage tank.

[0008] According to one aspect of the present invention, a mobile device includes: a guide rail having a chute extending in a first direction; a slider movably connected to the chute, with a rotating device disposed on the slider; and a first driving device for driving the slider to drive the rotating device to reciprocate along the chute.

[0009] According to one aspect of the present invention, the first driving device is a rotary motor, a ball screw is disposed in the chute of the guide rail, and a nut cooperating with the ball screw is embedded in the slider.

[0010] According to one aspect of the present invention, the rotating device further includes: a turntable connected to the semiconductor detection device, the turntable being rotatably connected to one end of a rotating shaft, and the other end of the rotating shaft being connected to the slider; and a second driving device for driving the turntable to rotate around the rotating shaft.

[0011] According to one aspect of the present invention, the radionuclide retention measurement system further includes a support plate connected to the turntable, and the support plate is used for fixing the semiconductor detection device and the ranging module.

[0012] According to one aspect of the present invention, the radionuclide retention measurement system further includes a shielding device disposed on the support plate, and the shielding device is sleeved on the outer peripheral side of the probe.

[0013] According to one aspect of the present invention, the radionuclide retention measurement system further includes a data processing device electrically connected to the semiconductor detection device and the electronic control unit.

[0014] According to one aspect of the present invention, the radionuclide retention measurement system further includes a mobile platform, and the mobile device, the electronic control unit and the data processing device are disposed on the mobile platform.

[0015] On the other hand, the present invention also provides a method for measuring radionuclide retention, which is applied to the radionuclide retention measurement system as described above. The method for measuring radionuclide retention includes: placing the radionuclide retention measurement system close to a target object containing a radionuclide; starting the mobile device and the rotating device of the radionuclide retention measurement system to drive the semiconductor detection device to move, so that the probe of the semiconductor detection device detects the energy peaks and net peak areas of the radionuclides with geometric shapes in the target object; using the ranging module of the radionuclide retention measurement system to measure the distance between the probe and the radionuclide; establishing an analysis model according to the geometric shape of the radionuclide retention and the distance between the probe and the radionuclide, and calculating the detection efficiency corresponding to different energy peaks to obtain the composition and mass of the radionuclide retention.

[0016] A nuclide retention measurement system and measurement method provided by the present invention can detect the energy peak and net peak area of nuclides in the nuclide retention with a geometric shape by driving a semiconductor detection device to move under the drive of a moving device and a rotating device, and perform modeling analysis based on the distance between the probe and the nuclide measured by a ranging module to achieve quantitative measurement of the nuclide retention, improving the measurement accuracy and measurement efficiency of the nuclide retention. Description of the Drawings

[0017] The features, advantages and technical effects of exemplary embodiments of the present invention will be described below with reference to the drawings. The drawings are not drawn to actual scale.

[0018] Figure 1 is a front view structural schematic diagram of a nuclide retention measurement system provided by an embodiment of the present invention;

[0019] Figure 2 is Figure 1 a side view structural schematic diagram of the nuclide retention measurement system shown;

[0020] Figure 3 is Figure 1 a structural schematic diagram of the moving device in the nuclide retention measurement system shown;

[0021] Figure 4 is Figure 1 a structural schematic diagram of the rotating device in the nuclide retention measurement system shown;

[0022] Figure 5 is a flowchart of a nuclide retention measurement method provided by an embodiment of the present invention.

[0023] Description of the Reference Numerals:

[0024] 1 - Moving device; 11 - Guide rail; 12 - Slide block; 13 - First driving device; 2 - Rotating device; 21 - Rotating shaft; 22 - Turntable; 23 - Second driving device; 24 - Support plate; 3 - Semiconductor detection device; 31 - Probe; 32 - Containment tank; 4 - Ranging module; 5 - Electric control unit; 6 - Shielding device; 7 - Data processing device; 8 - Moving platform; X - First direction; Y - Second direction. Detailed Embodiments

[0025] The features and exemplary embodiments of various aspects of the present invention will be described in detail below. In the following detailed description, many specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be apparent to those skilled in the art that the present invention may be practiced without some of these specific details. The following description of the embodiments is only provided to provide a better understanding of the present invention by way of illustrating examples of the present invention. In the drawings and the following description, at least the well-known structures and techniques of the regions are not shown in order to avoid unnecessarily obscuring the present invention; and, for clarity, the dimensions of the regional structures may be exaggerated. In addition, the features, structures, or characteristics described below may be combined in any suitable manner in one or more embodiments.

[0026] The orientation terms appearing in the following description are all the directions shown in the figures and do not limit the specific structure of the present invention. In the description of the present invention, it should also be noted that unless otherwise clearly specified and limited, the terms "installation" and "connection" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be directly connected or indirectly connected. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0027] For a better understanding of the present invention, the following combines Figures 1 to 5 A nuclide retention measurement system and measurement method provided by an embodiment of the present invention are described in detail.

[0028] To ensure the safety of nuclides, the evaluation of the unknown loss of nuclides is usually used as the main technical means, that is, to confirm whether the unknown loss of nuclides during use meets the limit requirements of relevant national management regulations, so as to effectively prevent the illegal transfer of nuclides due to internal factors. The unknown loss of nuclides generally exists in the retention amount of nuclear materials. The measurement of the retention amount of nuclear materials is of great significance for nuclear material recovery, accounting, safe operation of facilities, equipment decontamination and decommissioning.

[0029] The measurement of the nuclide retention amount generally uses empirical estimation methods, which cannot guarantee the accuracy of the estimation and has low reliability. Or, methods such as representative sampling detection and testing of similar equipment, endoscopic observation, destructive test detection, external irradiation dose (hot spot) detection, and establishment of a weight gain model are used to calculate by equipment and material categories. These methods have complex sampling, are even difficult to implement, and have great difficulties in measurement. The geometric structure of the container, the spatial conditions it is in, the medium composition of the retention amount, etc. will all affect the measurement results, and it cannot be guaranteed that the finally measured nuclide retention amount can reflect the actual situation.

[0030] Therefore, referring to Figure 1 and Figure 2, a nuclide retention measurement system provided by the present invention is used to measure the nuclide retention in a target object, which can be a process pipeline. The nuclide retention measurement system includes: a moving device 1, a rotating device 2, a semiconductor detection device 3, a ranging module 4, and an electric control unit 5.

[0031] The moving device 1 is movable along the first direction X. Optionally, the moving device 1 is a lifting device, and the first direction X is the vertical direction, which is convenient for controlling the movement of the moving device 1.

[0032] The rotating device 2 is arranged on the moving device 1. The rotating shaft 21 of the rotating device 2 extends along the second direction Y and can move along the first direction X with the moving device 1. The first direction X and the second direction Y are intersectingly arranged. Optionally, the second direction Y is perpendicularly arranged to the first direction X, which is convenient for manufacturing and fixing the rotating device 2. When the first direction X is the vertical direction, the second direction Y is the horizontal direction.

[0033] The semiconductor detection device 3 is connected to the rotating device 2 and can rotate with the rotating device 2. The semiconductor detection device 3 includes a probe 31, and the probe 31 is used to detect the energy peak and net peak area of the nuclide with a geometric shape in the target object. The probe 31 of the semiconductor detection device 3 moves back and forth driven by the moving device 1 and the rotating device 2 to scan the nuclide retention in the target object, improving the detection efficiency of the nuclide retention.

[0034] The ranging module 4 is connected to the probe 31 and is used to measure the distance between the probe 31 and the nuclide. The ranging module 4 can be a laser ranging sensor or an infrared sensor.

[0035] The electric control unit 5 is electrically connected to the semiconductor detection device 3 and the ranging module 4. The electric control unit 5 establishes an analysis model according to the geometric shape of the nuclide retention and the distance between the probe 31 and the nuclide, calculates the detection efficiency corresponding to different energy peaks, and obtains the composition and mass of the nuclide retention.

[0036] Optionally, the electric control unit 5 includes a passive efficiency calibration algorithm and an energy spectrum analysis algorithm integrated in a computer. The passive efficiency calibration algorithm is used to perform on-site modeling according to the geometric shape of the nuclide retention and the distance between the probe 31 and the nuclide, calculate the detection efficiency corresponding to different energy peaks, and obtain a detection efficiency curve. Then, the data of the detection efficiency curve is input into the energy spectrum analysis algorithm to obtain the energy spectrum diagram of the γ-ray in the nuclide. According to the net count rate of the full energy peak for energy spectrum analysis, generally when the net count rate is above 10000, the activity of the nuclide can be obtained, and finally the composition and mass of the nuclide retention can be obtained.

[0037] A nuclide retention measurement system provided by an embodiment of the present invention can detect the energy peak and net peak area of nuclides in a nuclide retention amount with a geometric shape by driving a semiconductor detection device 3 under the drive of a moving device 1 and a rotating device 2, and perform modeling analysis based on the distance between a probe 31 and the nuclides measured by a ranging module 4, so as to realize the quantitative measurement of the nuclide retention amount, and improve the measurement accuracy and measurement efficiency of the nuclide retention amount.

[0038] The following further describes in detail the specific structure of the nuclide retention measurement system provided by the embodiment of the present invention in conjunction with the accompanying drawings.

[0039] The energy of γ-rays generated by radioactive nuclides generally ranges from keV to MeV. Since it is uncharged, it cannot directly ionize matter when passing through matter and cannot be directly detected. Therefore, the detection of γ-rays mainly depends on its interaction with atoms in matter when passing through matter and transferring all or part of the photon energy to an electron in the absorbing material. This interaction exhibits the mutability and diversity of photons, and mainly produces three different types of interactions in the absorbing material: the photoelectric effect, the Compton effect, or the pair production effect. The secondary electrons (photoelectrons) generated then cause ionization and excitation of the matter, forming an electric pulse stream, and the amplitude of the electric pulse is proportional to the energy of the γ-ray. Among the three effects, in the photoelectric effect, the γ-ray transfers all its energy to the photoelectron to generate a full energy peak, which is the main signal used for qualitative and quantitative analysis in the spectrometer system; while the Compton effect or the pair production effect will cause interference and should be suppressed as much as possible.

[0040] Optionally, the semiconductor detection device 3 can be a high-purity germanium detector for energy spectrum measurement of γ-rays. As Figure 1 、 2 shown, the semiconductor detection device 3 further includes a containment tank 32 connected to the probe 31, and the containment tank 32 is used to contain liquid nitrogen. Since the high-purity germanium detector needs to work at a low temperature, the liquid nitrogen contained in the containment tank 32 generally needs to be cooled for 4 hours before work.

[0041] Optionally, the nuclide retention measurement system provided by the embodiment of the present invention further includes an inflation device (not shown in the figure), and the inflation device is used to supply liquid nitrogen to the containment tank 32. Optionally, a foot-operated inflation device is used to fill the liquid nitrogen, which is convenient for operation.

[0042] Furthermore, the moving device 1 includes: a guide rail 11, a slider 12, and a first driving device 13. Among them, the guide rail 11 has a chute extending along the first direction X. The slider 12 is movably connected to the chute, and the rotating device 2 is arranged on the slider 12. The first driving device 13 drives the slider 12 to drive the rotating device 2 to reciprocate along the chute.

[0043] The first driving device 13 can be any one of a hydraulic cylinder, a pneumatic cylinder, and an electric motor.

[0044] In some embodiments, the first driving device 13 can be any one of a hydraulic cylinder, a pneumatic cylinder, and a linear motor that outputs linear motion. The output shaft of the first driving device 13 is connected to the slider 12 to drive the slider 12 to drive the rotating device 2 to move back and forth along the chute.

[0045] In some embodiments, the first driving device 13 can also be a rotary motor that outputs rotational motion. A ball screw is embedded in the chute of the guide rail 11, and a nut that cooperates with the ball screw is embedded in the slider 12 to convert the rotational motion of the first driving device 13 into linear motion and drive the slider 12 to drive the rotating device 2 to move along the chute.

[0046] Furthermore, the rotating device 2 further includes a turntable 22 and a second driving device 23. The turntable 22 is connected to the semiconductor detection device 3. The turntable 22 is rotatably connected to one end of the rotating shaft 21, and the other end of the rotating shaft 21 is connected to the slider 12. The second driving device 23 drives the turntable 22 to rotate around the rotating shaft 21.

[0047] Optionally, the second driving device 23 is a rotary motor. Optionally, the rotation angle range of the turntable 22 is -90° to +90°, so as to detect nuclides within the maximum angle range as much as possible.

[0048] Furthermore, the nuclide retention amount measurement system provided by the embodiment of the present invention further includes a support plate 24 connected to the turntable 22. The support plate 24 is used to fix the semiconductor detection device 3 and the ranging module 4. The support plate 24 can ensure that the ranging module 4 is connected to the probe 31 as a whole, improving the measurement accuracy of the ranging module 4. Reinforcing ribs can be provided on the support plate 24 to improve the structural strength of the support plate 24 and prevent the support plate 24 from deforming due to the gravity of the semiconductor detection device 3.

[0049] Furthermore, the nuclide retention amount measurement system provided by the embodiment of the present invention further includes a shielding device 6 provided on the support plate 24. The shielding device 6 is sleeved on the outer peripheral side of the probe 31. The shielding device 6 can shield external signal interference and improve the detection accuracy of the probe 31.

[0050] Furthermore, the nuclide retention amount measurement system provided by the embodiment of the present invention further includes a data processing device 7 electrically connected to the semiconductor detection device 3 and the electronic control unit 5. Optionally, the data processing device 7 is a multi-channel analyzer (MCA), which is used to process the data detected by the semiconductor detection device 3 and input it to the electronic control unit 5, and the electronic control unit 5 then performs subsequent analysis work.

[0051] In the spectrometer system, the semiconductor detection device 3 is actually a photoelectric converter that converts the energy of photons into electrical pulses with amplitudes proportional to them. Then, the spectrometer amplifier shapes and linearly amplifies the pulses, and then sends them into the analog-to-digital converter, which converts the input signal into a set of digital signals according to the pulse amplitude, and sends the digital signals into the data processing device 7, where the spectrum diagram is formed and analyzed by relevant algorithms.

[0052] Furthermore, the nuclide retention measurement system provided by the embodiment of the present invention further includes a mobile platform 8, and the mobile device 1, the electronic control unit 5, and the data processing device 7 are arranged on the mobile platform 8. The bottom of the mobile platform 8 is provided with rollers, which facilitates moving the nuclide retention measurement system to any position for measurement work.

[0053] Optionally, a support base is arranged on the mobile platform 8, and the electronic control unit 5 and the data processing device 7 are placed on the support base.

[0054] The nuclide retention measurement system provided by the embodiment of the present invention uses a radioactive source Cs-137 for simulated point source measurement. The distance between the nuclide and the surface of the probe is 50 mm, and the shielding thickness is a stainless steel plate of 6.2 mm. The measurement result of the nuclide retention amount has an error of about 0.2% compared with the theory, which improves the measurement accuracy of the nuclide retention amount.

[0055] Refer to Figure 5 , the embodiment of the present invention also proposes a nuclide retention measurement method, which is applied to the nuclide retention measurement system as described above. The nuclide retention measurement method includes:

[0056] Step S1: Place the nuclide retention measurement system close to the target object containing the nuclide.

[0057] Step S2: Start the mobile device 1 and the rotating device 2 of the nuclide retention measurement system to drive the movement of the semiconductor detection device 3, so that the probe 31 of the semiconductor detection device 3 detects the energy peaks and net peak areas of the nuclides with geometric shapes in the target object. The semiconductor detection device 3 moves according to the different geometric shapes of the nuclides. For example, it moves along the first direction X driven by the mobile device 1 and rotates around the second direction Y driven by the rotating device 2, so that the probe can detect the energy peaks and net peak areas of all nuclides.

[0058] Step S3: Use the ranging module of the nuclide retention measurement system to measure the distance between the probe 31 and the nuclide.

[0059] Step S4: According to the geometric shape of the nuclide retention amount and the distance between the probe and the nuclide, establish an analysis model, calculate the detection efficiency corresponding to different energy peaks, so as to obtain the composition and mass of the nuclide retention amount.

[0060] Although the present invention has been described with reference to preferred embodiments, various modifications can be made thereto and components thereof can be replaced with equivalents without departing from the scope of the present invention. In particular, as long as there is no structural conflict, the technical features mentioned in each embodiment can be combined in any way. The present invention is not limited to the specific embodiments disclosed in the text, but includes all technical solutions falling within the scope of the claims.

Claims

1. A radionuclide retention measurement system, characterized in that, it includes: A mobile device (1) that can move along the first direction (X); A rotating device (2) provided on the mobile device (1), the rotating axis (21) of the rotating device (2) extends along the second direction (Y), and can move along the first direction (X) with the mobile device (1), and the first direction (X) intersects with the second direction (Y); A semiconductor detection device (3) connected to the rotating device (2) and capable of rotating with the rotating device (2), the semiconductor detection device (3) includes a probe (31), and the probe (31) is used to detect the energy peak and net peak area of the radionuclide with a geometric shape in the target object; A ranging module (4) connected to the probe (31) for measuring the distance between the probe (31) and the radionuclide; An electronic control unit (5) electrically connected to the semiconductor detection device (3) and the ranging module (4), and the electronic control unit (5) establishes an analysis model according to the geometric shape of the radionuclide retention amount and the distance between the probe (31) and the radionuclide, calculates the detection efficiency corresponding to different energy peaks, so as to obtain the composition and mass of the radionuclide retention amount.

2. The radionuclide retention measurement system according to claim 1, characterized in that, The semiconductor detection device (3) is a high-purity germanium detector, and the semiconductor detection device (3) further includes a storage tank (32) connected to the probe (31), and the storage tank (32) is used to store liquid nitrogen.

3. The radionuclide retention measurement system according to claim 2, characterized in that, It further includes an inflation device for supplying liquid nitrogen to the storage tank (32).

4. The radionuclide retention measurement system according to claim 1, characterized in that, The mobile device (1) includes: A guide rail (11) having a chute extending along the first direction (X); A slider (12) movably connected to the chute, and the rotating device (2) is provided on the slider (12); A first driving device (13) for driving the slider (12) to drive the rotating device (2) to reciprocate along the chute.

5. The radionuclide retention measurement system according to claim 4, characterized in that, The first driving device (13) is a rotating motor, a ball screw is provided in the chute of the guide rail (11), and a nut cooperating with the ball screw is embedded in the slider (12).

6. The radionuclide retention measurement system according to claim 4, characterized in that, The rotating device (2) further includes: A turntable (22) connected to the semiconductor detection device (3), the turntable (22) is rotatably connected to one end of the rotating shaft (21), and the other end of the rotating shaft (21) is connected to the slider (12); A second driving device (23) for driving the turntable (22) to rotate around the rotating shaft (21).

7. The radionuclide retention measurement system according to claim 6, characterized in that, It further includes a support plate (24) connected to the turntable (22), and the support plate (24) is used to support the semiconductor detection device (3) and the ranging module (4).

8. The nuclide retention amount measurement system according to claim 7, characterized in that it further includes a shielding device (6) disposed on the support plate (24), and the shielding device (6) is sleeved on the outer peripheral side of the probe (31).

9. The nuclide retention amount measurement system according to claim 1, characterized in that it further includes a data processing device (7) electrically connected to the semiconductor detection device (3) and the electronic control unit (5).

10. The nuclide retention amount measurement system according to claim 9, characterized in that it further includes a mobile platform (8), and the mobile device (1), the electronic control unit (5) and the data processing device (7) are disposed on the mobile platform (8).

11. A nuclide retention amount measurement method, applied to the nuclide retention amount measurement system according to any one of claims 1 to 10, the nuclide retention amount measurement method comprises: placing the nuclide retention amount measurement system close to a target object containing a nuclide; starting the mobile device (1) and the rotating device (2) of the nuclide retention amount measurement system to drive the semiconductor detection device (3) of the nuclide retention amount measurement system to move, so that the probe (31) of the semiconductor detection device (3) detects the energy peak and net peak area of the nuclide with a geometric shape in the target object; measuring the distance between the probe (31) and the nuclide through the ranging module (4) of the nuclide retention amount measurement system; establishing an analysis model according to the geometric shape of the nuclide retention amount and the distance between the probe (31) and the nuclide, calculating the detection efficiency corresponding to different energy peaks, so as to obtain the composition and mass of the nuclide retention amount.

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