Nuclear waste liquid gamma detection device

Abstract

The invention discloses a nuclear waste liquid gamma detection device which is communicated with a nuclear waste liquid discharge pipeline and comprises a measuring cylinder for containing nuclear waste liquid and an annular sodium iodide crystal detector fixedly assembled in the measuring cylinder. The maximum outer diameter of the annular sodium iodide crystal detector is smaller than the inner diameter of the measuring cylinder, and the distance between the bottom of the annular sodium iodide crystal detector and the bottom of the measuring cylinder is L; the annular sodium iodide crystal detector is provided with an annular sodium iodide crystal and an annular shell, the sodium iodide crystal is arranged in the shell, and the top of the shell is fixedly connected with a plurality of photomultiplication and signal processing assemblies coupled with the sodium iodide crystal. The nuclear waste liquid gamma detection device has the characteristics of low detection lower limit and high efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of nuclear radiation detection, in particular to a nuclear waste liquid gamma detection device. Background Art

[0002] During the power generation process at nuclear power plants, radioactive materials are released into water, forming liquid nuclear waste. This waste is sometimes temporarily discharged. During this temporary discharge, radioactivity testing and analysis are required to ensure that the radioactive content is within safety standards and to prevent harm to the environment and public health.

[0003] In the prior art, gamma radiation activity in nuclear wastewater is typically detected using a sodium iodide detector with columnar sodium iodide crystals. These detectors are placed in temporary nuclear wastewater discharge pipelines for gamma radiation detection. However, while these detectors are capable of detecting gamma radiation activity in nuclear wastewater, their placement in the discharge pipeline limits their measurement due to the pipeline's size. This results in an insufficient volume of radioactive wastewater for the detector to measure, leading to a high detection limit and an inability to accurately measure the gamma activity concentration of low-level radioactive nuclear wastewater. Furthermore, the columnar sodium iodide crystals have only sidewalls and a bottom for detection, resulting in low detection efficiency. Summary of the Invention

[0004] Based on this, it is necessary to provide a nuclear waste liquid gamma detection device with a low detection limit and high efficiency to address the above technical problems.

[0005] The present invention provides a nuclear waste liquid gamma detection device, which is connected to a nuclear waste liquid discharge pipeline and comprises a measuring cylinder for containing the nuclear waste liquid and an annular sodium iodide crystal detector fixedly mounted inside the measuring cylinder;

[0006] The maximum outer diameter of the annular sodium iodide crystal detector is smaller than the inner diameter of the measuring tube, and the distance between the bottom of the annular sodium iodide crystal detector and the bottom of the measuring tube is L;

[0007] The annular sodium iodide crystal detector is provided with an annular sodium iodide crystal and an annular shell. The sodium iodide crystal is arranged inside the shell. The top of the shell is fixedly connected with multiple photoelectric multiplication and signal processing components coupled with the sodium iodide crystal.

[0008] In one embodiment, a support seat is provided inside the measuring cylinder, and the support seat is provided with a fixing plate and a groove ring, the fixing plate is vertically fixedly connected to the inner wall of the measuring cylinder, and the groove ring is integrally connected to the middle part of the fixing plate, and the opening of the groove ring faces upward;

[0009] The fixing plate is annular, and the outer diameter of the fixing plate is equal to the inner diameter of the measuring cylinder;

[0010] The outer shell is sleeved inside the groove ring, and the photoelectric multiplier and signal processing components are located above the fixing plate.

[0011] In one embodiment, a cover is fixedly mounted on the top of the measuring cylinder. The cover is provided with a plurality of first through holes, the number of which is equal to the number of the photomultiplier and signal processing components. Each photomultiplier and signal processing component is inserted into a first through hole.

[0012] In one embodiment, the nuclear waste liquid gamma detection device is further provided with a liquid outlet pipe and a liquid inlet pipe;

[0013] The cover plate is provided with a second through hole, the fixed plate is provided with a first liquid outlet hole, a sealing plate is provided at the top of the central cavity of the shell, the sealing plate is fixedly connected to the top of the groove ring, the sealing plate is provided with a second liquid outlet hole, one end of the liquid outlet pipe is connected to the nuclear waste liquid discharge pipeline, and the other end of the liquid outlet pipe passes through the second through hole and is connected to both the first liquid outlet hole and the second liquid outlet hole;

[0014] A liquid inlet hole is provided at the bottom of the measuring cylinder, one end of the liquid inlet pipe is connected to the nuclear waste liquid discharge pipeline, and the other end of the liquid inlet pipe is connected to the liquid inlet hole.

[0015] In one embodiment, L≥10 cm.

[0016] In one embodiment, the top of the housing is fixedly connected to the fixing plate via a plurality of Z-shaped connecting pieces.

[0017] In one embodiment, a foldable bracket is further provided at the bottom of the measuring cylinder, and the bracket is fixedly connected to the measuring cylinder.

[0018] In one embodiment, a grip is provided on the top of the cover plate, and the grip is fixedly connected to the cover plate.

[0019] The present invention has the following beneficial effects: the nuclear waste liquid gamma detection device of the present invention can be installed on and connected to a nuclear waste liquid discharge pipeline, and uses an annular sodium iodide crystal detector to detect the gamma radioactivity of the nuclear waste liquid entering a measuring tube. The measuring tube can increase the volume of the radioactive nuclear waste liquid to be measured, thereby lowering the detection limit. In addition, the sodium iodide crystal of the annular sodium iodide crystal detector is annular, allowing nuclear waste liquid to enter the central cavity of the housing. The detection surface of the annular sodium iodide crystal not only includes the side walls and bottom, but also the central inner wall, which can increase the detection efficiency of the sodium iodide crystal. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic structural diagram of a nuclear waste liquid gamma detection device provided in an embodiment of the present invention;

[0021] Figure 2 for Figure 1 One of the cross-sectional diagrams along the axis of the detection tube;

[0022] Figure 3 A schematic structural diagram of a ring-shaped sodium iodide crystal detector provided in an embodiment of the present invention;

[0023] Figure 4 for Figure 3 One of the schematic cross-sections along the axis of a sodium iodide crystal;

[0024] Figure 5 A schematic structural diagram of a support base provided in an embodiment of the present invention.

[0025] Explanation of the reference numerals: 100, measuring cylinder; 110, cover plate; 120, gripper; 200, annular sodium iodide crystal detector; 210, housing; 220, sodium iodide crystal; 230, photomultiplier and signal processing assembly; 300, support base; 310, fixing plate; 320, groove ring; 330, sealing plate; 340, first liquid outlet; 400, liquid outlet pipe; 500, liquid inlet pipe; 600, bracket. DETAILED DESCRIPTION

[0026] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0027] It should be noted that in the description of the present invention, “upper”, “lower”, “top”, “bottom”, orientation or position relationship is based on the attached Figure 1 Regarding the orientation or positional relationship shown, it should be understood that these orientation terms are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, it should not be understood as a limitation on the present invention.

[0028] In one embodiment, Figure 1 and Figure 2 As shown, the nuclear waste liquid gamma detection device of this embodiment is connected to the nuclear waste liquid discharge pipeline, and includes a measuring cylinder 100 for containing the nuclear waste liquid and an annular sodium iodide crystal detector 200 fixedly assembled inside the measuring cylinder 100;

[0029] The maximum outer diameter of the annular sodium iodide crystal detector 200 is smaller than the inner diameter of the measuring tube 100. A distance L is defined between the bottom of the annular sodium iodide crystal detector 200 and the bottom of the measuring tube 100. This creates a nuclear waste storage space between the annular sodium iodide crystal detector 200 and the inner wall of the measuring tube 100, thereby increasing the nuclear waste measurement volume. Specifically, L is ≥ 10 cm.

[0030] like Figure 3 and Figure 4As shown, the annular sodium iodide crystal detector 200 is provided with an annular sodium iodide crystal 220 and an annular shell 210. The sodium iodide crystal 220 is arranged inside the shell 210. A plurality of photoelectric multiplication and signal processing components 230 coupled with the sodium iodide crystal 220 are fixedly connected to the top of the shell 210.

[0031] Specifically, the photomultiplier and signal processing assembly 230 includes a photomultiplier tube, a voltage divider, and a signal processing circuit. The photomultiplier tube is coupled to a sodium iodide crystal 220. When gamma rays from the radioactive liquid in the sodium iodide crystal 220 detector are incident on the crystal, the crystal generates fluorescent photons in the visible light phase. These fluorescent photons then strike the photocathode of the photomultiplier tube, generating photoelectrons due to the photoelectric effect. After being amplified by the dynodes of the photomultiplier tube, the photoelectrons are output at the anode, generating electrical pulse signals that can be processed and analyzed by the voltage divider and signal processing circuitry.

[0032] The provision of measuring tube 100 can increase the volume of radioactive nuclear waste to be measured, thereby lowering the detection limit. Once the nuclear waste enters measuring tube 100, the outer wall, inner wall, and bottom of the annular sodium iodide crystal 220 can all detect gamma radiation, enhancing the detection efficiency of the nuclear waste gamma detection device.

[0033] Specifically, the measuring cylinder 100 in this embodiment is made of stainless steel, and is designed to have an inner diameter no greater than 30 cm, an inner height no greater than 30 cm, and a weight less than 10 kg.

[0034] Preferably, the sodium iodide crystal 220 has an outer diameter of 6 inches, an inner diameter of 2 inches, and a height of 6 inches. To ensure the energy resolution of the detector, the photomultiplier tube is 1.5 inches in size. The number of photomultiplier and signal processing components 230 is four.

[0035] In one embodiment, Figure 5 As shown, a support base 300 is provided inside the measuring tube 100, and the support base 300 is provided with a fixing plate 310 and a groove ring 320. The fixing plate 310 is vertically fixedly connected to the inner wall of the measuring tube 100, and the groove ring 320 is integrally connected to the middle of the fixing plate 310, and the opening of the groove ring 320 is upward; the fixing plate 310 is annular, and the outer diameter of the fixing plate 310 is equal to the inner diameter of the measuring tube 100; the outer shell 210 is sleeved on the inside of the groove ring 320, and the photoelectric multiplier and signal processing component 230 is located above the fixing plate 310.

[0036] In this embodiment, the groove ring 320 is disposed at the center of the fixing plate 310 , and the fixing plate 310 is sleeved on the outer side of the groove ring 320 .

[0037] In one embodiment, a cover plate 110 is fixedly mounted on the top of the measuring tube 100. The cover plate 110 is provided with a plurality of first through holes, the number of which is equal to the number of the photomultiplier and signal processing components 230. Each photomultiplier and signal processing component 230 is inserted into a first through hole.

[0038] In one embodiment, the nuclear waste liquid gamma detection device is also provided with a liquid outlet pipe 400 and a liquid inlet pipe 500; the cover plate 110 is provided with a second through hole, the fixed plate 310 is provided with a first liquid outlet hole 340, and a sealing plate 330 is provided at the top of the central cavity of the outer shell 210. The sealing plate 330 is fixedly connected to the top of the groove ring 320, and the sealing plate 330 is provided with a second liquid outlet hole. One end of the liquid outlet pipe 400 is connected to the nuclear waste liquid discharge pipeline, and the other end of the liquid outlet pipe 400 is connected to both the first liquid outlet hole 340 and the second liquid outlet hole after passing through the second through hole; a liquid inlet hole is provided at the bottom of the measuring cylinder 100, one end of the liquid inlet pipe 500 is connected to the nuclear waste liquid discharge pipeline, and the other end of the liquid inlet pipe 500 is connected to the liquid inlet hole.

[0039] Specifically, the liquid outlet pipe 400 is a three-way pipe, the liquid outlet portion of the three-way pipe passes through the second through hole, and the two liquid inlets of the three-way pipe are respectively connected to the first liquid outlet hole 340 and the second liquid outlet hole.

[0040] The sealing plate 330 cooperates with the support base 300 to divide the interior of the fixed cylinder into two cavities, an upper cavity and an lower cavity. When the nuclear waste liquid gamma detection device is in use, the nuclear waste liquid only stays in the lower cavity and will not damage the photomultiplier and signal processing component 230.

[0041] In this embodiment, the nuclear waste liquid gamma detector is positioned in the middle of the discharge pipeline. The nuclear waste liquid discharge pipeline enters the nuclear waste liquid gamma detector and then flows from the nuclear waste liquid gamma detector into the discharge pipeline. Both the outlet pipe 400 and the inlet pipe 500 are connected to the discharge pipeline using quick connectors, which can reduce the time required to connect the pipelines during use.

[0042] In one embodiment, the top of the housing 210 is fixedly connected to the fixing plate 310 via multiple Z-shaped connecting pieces, enhancing the secure connection between the annular sodium iodide crystal detector 200 and the support base 300. A foldable bracket 600 is also provided at the bottom of the measuring tube 100 and is fixedly connected to the measuring tube 100. A gripper 120 is provided at the top of the cover plate 110 and is fixedly connected to the cover plate 110, facilitating movement of the device.

[0043] The above-described embodiments merely represent several implementation methods of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make various modifications and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A nuclear waste liquid gamma detection device, characterized in that: The device is connected to a nuclear waste liquid discharge pipeline and comprises a measuring cylinder (100) for containing the nuclear waste liquid and an annular sodium iodide crystal detector (200) fixedly mounted inside the measuring cylinder (100); The maximum outer diameter of the annular sodium iodide crystal detector (200) is smaller than the inner diameter of the measuring cylinder (100), and the distance between the bottom of the annular sodium iodide crystal detector (200) and the bottom of the measuring cylinder (100) is L; The annular sodium iodide crystal detector (200) is provided with an annular sodium iodide crystal (220) and an annular housing (210); the sodium iodide crystal (220) is arranged inside the housing (210); and a plurality of photoelectric multiplication and signal processing components (230) coupled to the sodium iodide crystal (220) are fixedly connected to the top of the housing (210).

2. The nuclear waste liquid gamma detection device according to claim 1, characterized in that: A support seat (300) is provided inside the measuring cylinder (100), and the support seat (300) is provided with a fixing plate (310) and a groove ring (320), wherein the fixing plate (310) is vertically fixedly connected to the inner wall of the measuring cylinder (100), and the groove ring (320) is integrally connected to the middle part of the fixing plate (310), and the opening of the groove ring (320) is upward; The fixing plate (310) is annular, and the outer diameter of the fixing plate (310) is equal to the inner diameter of the measuring cylinder (100); The housing (210) is sleeved inside the groove ring (320), and the photoelectric multiplication and signal processing component (230) is located above the fixing plate (310).

3. The nuclear waste liquid gamma detection device according to claim 2, characterized in that: A cover plate (110) is fixedly mounted on the top of the measuring cylinder (100), and the cover plate (110) is provided with a plurality of first through holes, the number of which is equal to the number of the photomultiplier and signal processing components (230), and each photomultiplier and signal processing component (230) is inserted into one of the first through holes.

4. The nuclear waste liquid gamma detection device according to claim 3, characterized in that: The nuclear waste liquid gamma detection device is further provided with a liquid outlet pipe (400) and a liquid inlet pipe (500); The cover plate (110) is provided with a second through hole, the fixed plate (310) is provided with a first liquid outlet (340), a sealing plate (330) is provided at the top of the central cavity of the housing (210), the sealing plate (330) is fixedly connected to the top of the groove ring (320), the sealing plate (330) is provided with a second liquid outlet, one end of the liquid outlet pipe (400) is communicated with the nuclear waste liquid discharge pipeline, and the other end of the liquid outlet pipe (400) passes through the second through hole and is communicated with both the first liquid outlet (340) and the second liquid outlet; A liquid inlet hole is provided at the bottom of the measuring cylinder (100), one end of the liquid inlet pipe (500) is connected to the nuclear waste liquid discharge pipeline, and the other end of the liquid inlet pipe (500) is connected to the liquid inlet hole.

5. The nuclear waste liquid gamma detection device according to claim 4, characterized in that: L≥10cm.

6. The nuclear waste liquid gamma detection device according to claim 5, characterized in that: The top of the housing (210) is fixedly connected to the fixing plate (310) via a plurality of Z-shaped connecting pieces.

7. The nuclear waste liquid gamma detection device according to claim 6, characterized in that: A foldable bracket (600) is also provided at the bottom of the measuring cylinder (100), and the bracket (600) is fixedly connected to the measuring cylinder (100).

8. The nuclear waste liquid gamma detection device according to claim 7, characterized in that: A gripper (120) is provided on the top of the cover plate (110), and the gripper (120) is fixedly connected to the cover plate (110).

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