A radioactive foam height nuclear monitoring system and method of use

Abstract

The present application relates to the technical field of radiation monitoring, in particular to a radioactive foam height nuclear monitoring system and a use method thereof.A radioactive foam height nuclear monitoring system, comprising: an ionization chamber detector; a collimating shielding module, the collimating shielding module is provided with a containing space, the ionization chamber detector is contained in the containing space, the collimating shielding module is provided with a collimating hole, and the collimating hole is suitable for particles generated from a self-radiation source.The present application provides a radioactive foam height nuclear monitoring system and a use method thereof, so as to solve the problem that a conventional radiation detector is difficult to withstand an extremely high irradiation environment, thereby affecting the detection accuracy.

Description

Technical Field

[0001] This invention relates to the field of radiation monitoring technology, specifically to a radioactive foam high-level nuclear monitoring system and its usage method. Background Technology

[0002] In the post-processing field, processes such as dissolution may generate foam.

[0003] The detection of foam is limited by the high background of radioactivity and the highly corrosive concentrated acid environment. A nuclear radiation detection device can be placed near the surface of the liquid solution of the device under test, and the height of the radioactive foam can be monitored by measuring the real-time dose rate using radioactivity.

[0004] Currently, in the field of spent fuel reprocessing, there is a lack of methods, devices, and systems for high-level nuclear monitoring of radioactive foam. Furthermore, conventional radiation detectors are unable to withstand extremely high radiation environments, affecting the accuracy of detection results. Summary of the Invention

[0005] In view of this, the present invention provides a radioactive foam high-level nuclear monitoring system and its usage method to solve the problem that conventional radiation detectors are difficult to withstand extremely high radiation environments, which affects the accuracy of detection results.

[0006] In a first aspect, the present invention provides a high-level nuclear monitoring system for radioactive foam, comprising: Ionization chamber detector; The collimation shielding module has a receiving space for accommodating an ionization chamber detector. The collimation shielding module also has a collimation aperture adapted to allow particles generated by a self-radiation source to pass through.

[0007] By setting up a collimation shielding module, the collimation shielding module can shield particles generated by radiation sources other than the collimation aperture, thereby preventing the ionization chamber detector from being exposed to a high-irradiation environment and ensuring the accuracy of the detection results.

[0008] In one optional embodiment, the ionization chamber detector has at least two detection chambers, the collimation shielding module has at least two collimation holes, and the detection chambers are arranged along the height direction of the ionization chamber detector.

[0009] In one optional embodiment, the collimation hole includes a first hole column and a second hole column, the first hole column and the second hole column each including at least one collimation hole, and the collimation holes of the first hole column and the second hole column are offset along the height direction of the collimation shielding module.

[0010] In one alternative implementation, one of the collimating holes corresponds to one section of the detection chamber.

[0011] In one alternative embodiment, the ionization chamber detector has an internal chamber with a plurality of isolation plates disposed therein, the plurality of isolation plates dividing the internal chamber into independent detection chambers.

[0012] In one optional embodiment, each of the detection chambers is provided with an isolation electrode plate on each side, and each of the detection chambers is provided with a collection electrode plate inside.

[0013] In one alternative embodiment, each of the detection chambers is filled with an inert gas mixture, each of the isolation plates is connected to a voltage transmission cable, and each of the collection plates is connected to a signal transmission cable.

[0014] In one optional embodiment, the system further includes a control cabinet connected to the ionization chamber detector. The control cabinet includes a signal acquisition unit and several analog-to-digital conversion units. Each analog-to-digital conversion unit corresponds to one signal transmission cable, and the signal acquisition unit is connected to several analog-to-digital conversion units.

[0015] In one optional implementation, a signal processing unit is further included, which is connected to the signal acquisition unit via a circuit.

[0016] A method for using a radioactive foam high-level nuclear monitoring system, wherein a collimation shielding module is used to shield particles generated by radiation sources other than the collimation aperture. Attached Figure Description

[0017] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of a radioactive foam height nuclear monitoring system according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the collimation shielding module according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the method for determining the height of radioactive foam according to the present invention; Figure 4 This is a schematic diagram of an ionization chamber detector according to an embodiment of the present invention.

[0019] Explanation of reference numerals in the attached drawings: 1. Collimation and shielding module; 101. Shielding shell; 102. First hole row; 103. Second hole row; 104. Collimation hole; 2. Ionization chamber detector; 201. Detection chamber; 202. Isolation plate; 203. Collection plate; 204. Central support shaft; 3. Detector pipe; 4. Shielding bracket; 5. Shielding wall; 6. Dissolving device; 7. Liquid layer; 8. Foam layer; 9. Control cabinet; 901. Cabinet; 902. Power supply unit; 903. Display unit; 904. Signal processing unit; 905. Signal acquisition unit; 10. Communication cabinet; 11. Control room. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] The following is combined with Figures 1 to 4 The following describes embodiments of the present invention.

[0022] According to an embodiment of the present invention, a radioactive foam height nuclear monitoring system is provided, comprising: an ionization chamber detector 2; a collimation shielding module 1, the collimation shielding module 1 having a receiving space for accommodating the ionization chamber detector 2, the collimation shielding module 1 having a collimation aperture 104 adapted to allow particles generated by a self-radiation source to pass through.

[0023] By setting up the collimation shielding module 1, the collimation shielding module 1 can shield particles generated by radiation sources other than the collimation aperture 104, so as to avoid the ionization chamber detector 2 being exposed to a high-irradiation environment and ensure the accuracy of the detection results.

[0024] In one embodiment, such as Figure 1 , Figure 2 As shown, the ionization chamber detector 2 has at least two detection chambers 201, and the collimation shielding module 1 has at least two collimation holes 104. The detection chambers 201 are arranged along the height direction of the ionization chamber detector 2 to facilitate the measurement of particle conditions of the radiation source along the height direction. In this embodiment, one collimation hole 104 corresponds to one detection chamber 201. Figure 1 As shown, it also includes a dissolving device 6, which contains a large amount of dissolving liquid. The liquid surface of this dissolving liquid is a liquid layer 7. When the dissolving liquid dissolves the core material, it generates a foam layer 8 containing a large amount of foam.

[0025] In one embodiment, such as Figure 1, Figure 2 As shown, the collimation hole 104 includes a first hole row 102 and a second hole row 103. The first hole row 102 and the second hole row 103 each include at least one collimation hole 104. The collimation holes 104 of the first hole row 102 and the collimation holes 104 of the second hole row 103 are offset along the height direction of the collimation shielding module 1. In this embodiment, the first hole row 102 (… Figure 2 The number of collimating holes 104 on the left side is 5, and the number of holes in the second row 103 is 5. Figure 2 The number of aligning holes 104 on the right side of the first hole column 102 is 5, and the aligning holes 104 of the second hole column 103 are provided between the adjacent aligning holes 104 of the first hole column 102 along the height direction. That is, the distance between the adjacent aligning holes 104 of the first hole column 102 along the height direction is greater than the height of the aligning holes 104 of the second hole column 103; the aligning holes 104 of the first hole column 102 are provided between the adjacent aligning holes 104 of the second hole column 103 along the height direction. That is, the distance between the adjacent aligning holes 104 of the second hole column 103 along the height direction is greater than the height of the aligning holes 104 of the first hole column 102. It should be noted that the height of the lowest collimating hole 104 in the first hole array 102 along the height direction is greater than the height of the other collimating holes 104, and the lowest collimating hole 104 is aligned with the separating surface between the foam layer 8 and the liquid layer 7 in the dissolution device 6. Preferably, the middle position of the lowest collimating hole 104 is aligned with the separating surface between the foam layer 8 and the liquid layer 7 to detect the foam layer 8 and the liquid layer 7 in the dissolution device 6. As the dissolution device 6 dissolves the nuclear material, a large amount of foam layer 8 is generated. As the foam layer 8 gradually rises, the sensitive area of ​​the ionization chamber detector 2 that is ionized through the collimating hole 104 of the collimation shielding module 1 increases accordingly. By calculating the signal strength of the collecting electrode in the sensitive area of ​​each single detection chamber 201, the height range of the foam in the dissolution device 6 is determined.

[0026] In one embodiment, such as Figure 1 , Figure 2 As shown, one collimation aperture 104 corresponds to one detection chamber 201, and there are ten detection chambers 201 in total. It should be noted that, as... Figure 1As shown, the collimation shielding module 1 is mounted on the shielding bracket 4. The collimation shielding module 1 is composed of a stainless steel shielding shell 101, a collimator made of tungsten-nickel-iron alloy, and a lead shielding body. The collimation shielding module 1 is installed horizontally outside the dissolving device 6, close to the surface of the solution in the solution pool. The collimator depth is 75mm, and the height of each collimation hole 104 is the same as the diameter of the detector's sensitive area, which is 20mm. The shielding body is 400mm high, 200mm wide, and 200mm deep. The function of the collimation shielding module 1 is to reduce the background radiation of the high-radioactivity environment to ensure a significant radioactive signal from the foam layer 8. The collimation shielding module 1 is mounted on the shielding bracket 4, which provides support for its installation.

[0027] In one embodiment, such as Figure 1 , Figure 2 As shown, the ionization chamber detector 2 has an internal chamber, and several isolation plates 202 are provided in the internal chamber. The several isolation plates 202 divide the internal chamber into independent detection chambers 201, so that each detection chamber 201 corresponds to a collimation hole 104.

[0028] In one embodiment, such as Figure 1 , Figure 2 , Figure 4 As shown, each of the detection chambers 201 has an isolation electrode plate 202 on each side, and a collection electrode plate 203 is provided inside each detection chamber 201. In this embodiment, as... Figure 4 As shown, adjacent detection chambers 201 share the same isolation plate 202, that is, a total of eleven isolation plates 202 are provided in the internal chamber to form ten detection chambers 201. Each detection chamber 201 is provided with a collecting plate 203, and the ten detection chambers 201 have a total of ten collecting plates 203. Each collecting plate 203 independently outputs a set of signals. Figure 4 As shown, it also includes a central support shaft 204, which supports the isolation electrode plate 202 and the collecting electrode plate 203.

[0029] In this embodiment, the ionization chamber detector section and the internal structural support components welded to the outer shell are both made of 316L stainless steel, possessing good corrosion resistance, pressure resistance, and shock resistance. The collecting electrode 203 and the isolating electrode 202 are both made of aluminum alloy. The insulating support material between the electrode and the outer shell is polyetheretherketone (PEEK), the sealing ring and density gasket are made of radiation-resistant nitrile rubber, and the connector uses a glass-sintered, airtight connector, giving the ionization chamber detector 2 excellent sealing and radiation resistance, ensuring long-term stable measurement in high-amplitude environments.

[0030] In one embodiment, such as Figure 1, Figure 2 As shown, each detection chamber 201 is filled with an inert gas mixture, and each isolation plate 202 is connected to a voltage transmission cable (different isolation plates 202 are connected to different voltage transmission cables). Each collection plate 203 is connected to a signal transmission cable (different collection plates 203 are connected to different signal transmission cables). In this embodiment, the inert gas mixture is an argon-helium mixture, with a filling pressure of 1 MPa, a mixing ratio of 1:1, and a measurement range of 50 mGy-500 Gy / h. The voltage transmission cables provide 1000V high voltage to the isolation plates 202. When external radiation particles pass through the collimation hole 104 and reach the detection chamber 201, the internal mixed reaction gas undergoes ionization. Ions are collected by each collection plate 203 in each detection chamber 201, forming a current signal, which is transmitted to the outside via the signal transmission cables. It should be noted that the voltage transmission cables and signal transmission cables in this embodiment are high-strength copper alloy cables with cross-linked polyethylene radiation-resistant triaxial shielded insulation. These cables have strong radiation resistance, capable of withstanding a cumulative dose of 1×10⁶ Gy. The triaxial shielding design isolates crosstalk between signals, giving the cables strong anti-interference capabilities, making them suitable for the complex environment of the dissolution device 6. Furthermore, after extending through the hollow channel of the central support shaft 204, the voltage transmission cables and signal transmission cables are connected to each isolation plate 202 via voltage transmission lines (adjacent isolation plates 202 have the same voltage). One signal transmission cable corresponds to one collecting plate 203. The inert gas mixture ionizes under radiation, causing the ionization chamber detector 2 to generate a detectable current signal. The gas mixture in the detection chamber 201 is suitable for measuring the radioactive foam of the continuous dissolution device 6.

[0031] In this embodiment, as Figure 1 As shown, it also includes a detector conduit 3. One end of the detector conduit 3 is welded to the collimation shielding module 1, and the other end passes through the shielding wall 5 to the orange / green zone room for the maintenance and installation of the ionization chamber detector 2. The detector conduit 3 is pre-embedded in the shielding wall 5 in an S-shaped bend. The end of the detector conduit 3 is sealed inside the collimation shielding module 1, which can effectively prevent gamma ray leakage. Voltage transmission cables and signal transmission cables are installed inside the detector conduit 3.

[0032] In one embodiment, such as Figure 1 , Figure 2As shown, it also includes a control cabinet 9, which is connected to the ionization chamber detector 2 via wiring. The control cabinet 9 includes a signal acquisition unit 905 and several analog-to-digital conversion units. Each analog-to-digital conversion unit corresponds to one signal transmission cable, and the signal acquisition unit 905 is connected to several analog-to-digital conversion units via wiring. Each analog-to-digital conversion unit converts the signal transmitted from one signal transmission cable into a digital signal, and then transmits it to the signal acquisition unit 905.

[0033] In one embodiment, such as Figure 1 , Figure 2 As shown, it also includes a signal processing unit 904, which is connected to the signal acquisition unit 905. The acquisition and processing unit collects and summarizes the digital signals from each analog-to-digital converter, converts the ten sets of digital signals into dose rate signals, and transmits them to the signal processing unit 904 via a communication port and an aviation connector for processing. In this embodiment, the signal acquisition unit 905 amplifies and integrates the acquired signals and transmits them to the signal processing unit 904 via an RS485 signal. The signal processing unit 904 analyzes, processes, and stores the signals uploaded by the signal acquisition unit 905, converts the measured signals into dose rate and foam height, and analyzes and judges whether the dose rate and foam height exceed the limits based on the set alarm thresholds.

[0034] In this embodiment, as Figure 1 As shown, the control cabinet 9 includes a cabinet body 901, which contains a power supply unit 902, a display unit 903, a signal processing unit 904, and a signal acquisition unit 905. The control cabinet 9 is connected to the communication cabinet 10 by a line, and the communication cabinet 10 is connected to the control room 11 by a line.

[0035] The signal processing unit 904 includes four RS485 interfaces, which can upload processed data to the display unit 903 and the communication cabinet 10. In addition, the signal processing unit 904 also reserves two analog input / output interfaces and two digital input / output interfaces, which can receive input signals from external devices or convert their own signals into analog and digital quantities before outputting them to external devices. The display unit 903 visualizes the ten measurement data uploaded by the signal processing unit 904. In this embodiment, a bar chart is used to display the dose rate and foam height corresponding to each section of the ionization chamber detector 2.

[0036] A method for using a radioactive foam high-level nuclear monitoring system includes the following steps: (1) Directional acquisition of radiation signals: By using the collimation shielding module 1 surrounding the multi-section ionization chamber detector 2, the ambient radiation is filtered directionally by its collimation hole 104 array to acquire the radiation signals of the foam layer 8 and the liquid layer 7 in the dissolving device 6. (2) Multi-node synchronous measurement: Vertically distributed ionization chamber detector 2 is used. When the inert gas mixture exceeds the pressure reference under the radiation, it is ionized through the high-pressure electrode, so that a current signal that can be detected by the collecting electrode is generated in the measurement chamber. The current signal is output through the signal transmission cable. Each section independently generates an electrical signal corresponding to the local radiation intensity. All detector section signals are collected synchronously to obtain the instantaneous radiation intensity distribution. (3) Calculation of foam height gradient: Based on the gradient change of the radiation intensity distribution, the interface height between the foam layer 8 and the liquid layer 7 is calculated by the signal processing core; (4) Graded alarm triggering: When the signal strength of any detector exceeds the preset first threshold, a primary alarm is triggered; when the calculated foam height exceeds the preset second threshold, a secondary alarm is triggered.

[0037] In the above steps, the gradient calculation is specifically as follows: plot the relationship curve between the position of each detection segment and the radiation intensity; identify the intensity abrupt change points in the curve, and determine the foam height in combination with the preset conversion coefficient; the first threshold is 100 times the background dose rate of a single segment, and the second threshold is the maximum allowable height of the foam layer 8, which is 200 mm.

[0038] In this embodiment, the ionization chamber detector 2 has external dimensions (diameter × height) of φ83mm × 350mm. It enters the measurement position vertically through the shielding wall 5 from the green / orange zone via the detector pipe 3 and extends into the collimation shielding module 1 to detect the foam layer 8 and the feed liquid layer 7 in the dissolution device 6. The ionization chamber detector 2 comprises a total of 10 detection chambers 201, with the bottommost detection chamber 201 positioned below the surface of the feed liquid layer 7. The second detection chamber 201, from bottom to top, is positioned above the surface of the feed liquid layer 7. The remaining chambers are arranged sequentially, with each detection area being 20mm, and the entire sensitive length of the ionization chamber detector 2 is 200mm.

[0039] The present invention provides the following advantages: (1) By setting a collimation shielding module 1, the collimation shielding module 1 can shield particles generated by radiation sources other than the collimation hole 104, so as to avoid the ionization chamber detector 2 being exposed to a high-irradiation environment and ensure the accuracy of the detection results. The multi-section ionization chamber detector 2 is wrapped with a lead shield with multiple collimation holes 104 to ensure the signal-to-noise ratio of each section detector. (2) An irradiation-resistant ionization chamber detector 2 is used to realize position-sensitive γ dose rate measurement across multiple orders of magnitude in a high-irradiation area. (3) A multi-channel response signal acquisition and processing circuit is used to realize the synchronous acquisition and analysis of pulse signals of multiple sections detectors. (4) Physical algorithms and special analysis software are used to analyze and compare the acquired signals to obtain foam height information. (5) Compared with conventional decimeter-level conventional radiation detectors, this application can meet the requirements for monitoring foam height and achieve millimeter-level position resolution accuracy.

[0040] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A radioactive foam high-level nuclear monitoring system, characterized in that, include: Ionization chamber detector (2); The collimation shielding module (1) is provided with a receiving space and a collimation hole (104). The receiving space is used to accommodate an ionization chamber detector (2). The collimation hole (104) is adapted to allow the passage of particles generated by a self-radiation source. The ionization chamber detector (2) is provided with at least two detection chambers (201), and the collimation shielding module (1) is provided with at least two collimation holes (104). The detection chambers (201) are arranged along the height direction of the ionization chamber detector (2). The collimation holes (104) include a first hole row (102) and a second hole row (103). The first hole row (102) and the second hole row (103) each include at least one collimation hole (104). The collimation holes (104) of the first hole row (102) and the collimation holes (104) of the second hole row (103) are offset along the height direction of the collimation shielding module (1). The spacing between adjacent collimating holes (104) in the first hole row (102) along the height direction is greater than the height of the collimating holes (104) in the second hole row (103); One of the collimation holes (104) is provided for one section of the detection chamber (201).

2. The radioactive foam high-level nuclear monitoring system according to claim 1, characterized in that, The ionization chamber detector (2) has an internal chamber, and a plurality of isolation plates (202) are provided in the internal chamber to divide the internal chamber into independent detection chambers (201).

3. The radioactive foam high-level nuclear monitoring system according to claim 2, characterized in that, Each of the detection chambers (201) has an isolation electrode plate (202) on each side and a collection electrode plate (203) inside each of the detection chambers (201).

4. The radioactive foam high-level nuclear monitoring system according to claim 3, characterized in that, Each of the detection chambers (201) is filled with an inert gas mixture, each of the isolation plates (202) is connected to a voltage transmission cable, and each of the collection plates (203) is connected to a signal transmission cable.

5. The radioactive foam high-level nuclear monitoring system according to claim 4, characterized in that, It also includes a control cabinet (9), which is connected to the ionization chamber detector (2) by line. The control cabinet (9) includes a signal acquisition unit (905) and several analog-to-digital conversion units. One analog-to-digital conversion unit corresponds to one signal transmission cable. The signal acquisition unit (905) is connected to several analog-to-digital conversion units by line.

6. The radioactive foam high-level nuclear monitoring system according to claim 5, characterized in that, It also includes a signal processing unit (904), which is connected to the signal acquisition unit (905) by line.

7. A method of using a radioactive foam height nuclear monitoring system, for using the radioactive foam height nuclear monitoring system of claim 1, characterized in that, The collimation shielding module (1) shields particles generated by radiation sources other than the collimation aperture (104).

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