Detection equipment and detection method for liquid radioactive activity

Abstract

The invention provides detection equipment and a detection method for liquid radioactivity, and belongs to the technical field of radioactive liquid detection, and the detection equipment comprises a shielding body, a sample container and a detection device. Wherein the shielding body is internally provided with an accommodating cavity; the sample container is arranged in the containing cavity, a groove is formed in the top of the sample container, a sample cavity is formed in the sample container, a liquid inlet pipe is arranged at the top of the sample container, a liquid outlet pipe is arranged at the bottom of the sample container, and the liquid inlet pipe and the liquid outlet pipe are communicated with the sample cavity; the detection device is arranged in the groove, and the detection end of the detection device faces the sample cavity. The detection equipment can be effectively integrated on a nuclear power plant pipeline or a storage tank, and online detection of nuclear power plant liquid effluent radionuclides can be completed with high resolution.

Description

Technical Field

[0001] The present invention relates to the technical field of radioactive waste detection, and in particular to a device and method for detecting liquid radioactive activity. Background Art

[0002] Currently, gamma nuclide monitoring of liquid effluents from nuclear power plants relies primarily on laboratory analysis. According to the "Technical Specifications for Effluent Monitoring at Nuclear Power Plants (National Nuclear Safety Administration

[2020] No. 44)," liquid effluents from nuclear power plants must be regularly collected and sent to the laboratory for analysis of radionuclide activity using a high-purity germanium (HPGe) gamma spectrometer.

[0003] However, this detection method is incapable of online monitoring of radionuclides in liquid effluents from nuclear power plants. The sampling and subsequent laboratory analysis method introduces a time delay, often requiring several hours for test results to be obtained from sampling to measurement in the effluent monitoring laboratory, making it difficult to provide a timely reflection of the level of radioactivity emitted. The sample transportation and testing process requires manual labor, which is complex and costly. Furthermore, sample calculations can distort activity levels due to evaporation and contamination, affecting the accuracy of test results.

[0004] Therefore, it is necessary to design a liquid radioactivity detection device and a detection method to improve the above problems. Summary of the Invention

[0005] The present invention provides a liquid radioactivity detection device and a detection method, which are used to improve the technical defect that existing liquid effluent radioactivity detection devices are difficult to realize on-line radioactivity activity detection of liquid effluent in nuclear power plants.

[0006] In a first aspect, the present invention provides a liquid radioactivity detection device, which includes a shielding body, a sample container, and a detection device.

[0007] The shielding body has a accommodating cavity inside; the sample container is arranged in the accommodating cavity, the top of the sample container is provided with a groove, the sample container has a sample cavity inside, the top of the sample container is provided with a liquid inlet pipe, the bottom of the sample container is provided with a liquid outlet pipe, the liquid inlet pipe and the liquid outlet pipe are connected to the sample cavity; the detection device is arranged in the groove, and the detection end of the detection device faces the sample cavity.

[0008] In one example of the present invention, the liquid inlet pipe extends to the outside of the shielding body, and a liquid inlet valve is provided on the liquid inlet pipe; the liquid outlet pipe is arranged at the middle position of the bottom wall of the sample chamber, and the liquid outlet pipe extends from the bottom of the shielding body in the height direction, and a liquid outlet valve is provided on the liquid outlet pipe.

[0009] In an example of the present invention, the sample container is further provided with a vent, and the vent is located at the top of the sample container.

[0010] In an example of the present invention, the detection device includes a shell and a detector array, the shell is placed in the groove, the detector array is encapsulated in the shell, and the detection end of the detector array faces one end of the shell close to the sample cavity.

[0011] In an example of the present invention, the wall thickness of the projection area covered by the detector array on the shell along the height direction is 0.5-1 mm.

[0012] In an example of the present invention, the detector array includes at least four gamma-ray detectors arranged in an array on a detection end plane, and the gamma-ray detectors are CZT detectors.

[0013] In one example of the present invention, part of the shell is located outside the groove, a first vent is provided on the side wall of the shell, a second vent is provided on the top wall of the shell facing away from the sample chamber, and a cooling fan is also provided in the shell, and the cooling fan faces the detector array.

[0014] In an example of the present invention, the wall of the shielding body includes a copper layer, a lead layer and a stainless steel layer arranged in sequence from the inside to the outside, and the volume of the lead layer in the shielding body accounts for more than 85%.

[0015] In a second aspect, the present invention further provides a method for detecting the radioactive activity of a liquid, the method being implemented using the detection device described in any one of the above examples, the method comprising: Obtaining a detection result obtained by a detection device on the liquid to be tested in the sample chamber; Determining the type of radioactive nuclides in the liquid to be tested based on the detection result; Determining the detection efficiency of the detection device for each type of radionuclide in the liquid to be tested based on the type of radionuclide; The radioactivity concentration of each type of radionuclide in the liquid to be tested is obtained based on the detection time, the detection result, the gamma ray emission probability corresponding to each type of radionuclide, and the detection efficiency.

[0016] In one example of the present invention, the step of obtaining the detection efficiency of each type of radionuclide includes: Based on the radioactive energy of the nuclides corresponding to the radioactive nuclides, the detection efficiency corresponding to each type of radionuclide is determined from the detection efficiency scale of the detection device; The process of obtaining the detection efficiency scale includes: Establishing an initial detection efficiency scale of the detection device for the liquid loaded in the sample cavity based on parameter information of the detection device and position information of the detection device relative to the sample cavity, wherein the initial detection efficiency scale includes a numerical relationship between the detection efficiency and the radioactive energy of the nuclide; Acquiring detection efficiency calibration data obtained by the detection device for detecting the standard nuclide liquid loaded in the sample chamber; The detection efficiency scale of the detection device for the liquid loaded in the sample chamber is determined based on the detection efficiency calibration data and the initial detection efficiency scale.

[0017] The detection device provided by the present invention can be integrated into nuclear power plant pipelines or storage tanks. By connecting the liquid inlet pipe to the pipeline or storage tank, the liquid to be tested in the pipeline is introduced into the sample container. This allows the detection device mounted on the top of the sample container to perform high-resolution radionuclide detection on the liquid to be tested introduced into the sample chamber. After the detection is completed, the liquid to be tested can be discharged into a waste liquid storage tank or an on-site discharge pipeline by opening the liquid outlet pipe. This detection device can be effectively integrated into nuclear power plant pipelines, achieving high-resolution online detection of radionuclides in liquids stored or transported in nuclear power plants. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings are incorporated into and constitute a part of the specification, illustrate embodiments consistent with the present application, and together with the specification, are used to explain the principles of the present application. Obviously, the drawings described below are only some embodiments of the present application. For those of ordinary skill in the art, other embodiments can be obtained based on these drawings without inventive efforts.

[0019] In the attached figure: Figure 1 A schematic structural diagram of a detection device in one embodiment of the present invention; Figure 2 A cross-sectional structural diagram of a detection device in one embodiment of the present invention; Figure 3 This is a schematic structural diagram of a sample container in one embodiment of the present invention; Figure 4 This is a schematic structural diagram of a detection device in one embodiment of the present invention; Figure 5 Schematic diagram of a flow chart of a method for detecting radioactivity concentration of liquid in one embodiment of the present invention; Figure 6 Schematic diagram of the process of calibrating detection efficiency of a detection device in one embodiment of the present invention.

[0020] Component number description: 100, shielding body; 110, shielding box; 120, top cover; 200, sample container; 210, groove; 220, accommodating chamber; 230, liquid inlet pipe; 240, liquid outlet pipe; 250, vent pipe; 300, detection device; 310, shell; 311, first vent; 312, second vent. DETAILED DESCRIPTION

[0021] The following describes the embodiments of the present invention through specific examples. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following examples and the features in the examples can be combined with each other unless they conflict. It should also be understood that the terms used in the examples of the present invention are for the purpose of describing specific embodiments, not for the purpose of limiting the scope of protection of the present invention. The test methods for which specific conditions are not specified in the following examples are generally carried out under conventional conditions or under the conditions recommended by the manufacturers.

[0022] It should be noted that the terms such as "upper", "lower", "left", "right", "middle" and "one" cited in this specification are only for the convenience of description and are not used to limit the scope of implementation of the present invention. Changes or adjustments to their relative relationships should be regarded as the scope of implementation of the present invention without substantially changing the technical content.

[0023] In the first aspect, Figures 1 to 3 As shown, the present invention provides a liquid radioactivity detection device, which includes a shielding body 100 , a sample container 200 and a detection device 300 .

[0024] like Figures 1 to 3As shown, the shielding body 100 has a housing 220 within it. The walls of the shielding body 100 are capable of absorbing and shielding radioactive radiation. A sample container 200 is disposed within the housing 220. A recess 210 recessed into the housing 220 is provided at the top of the sample container 200, and the sample container 200 has a sample cavity within it. A liquid inlet tube 230 is disposed at the top of the sample container 200. One end of the liquid inlet tube 230 is connected to the sample cavity, while the other end of the liquid inlet tube 230 extends outside the shielding body 100 and is connected to the monitoring pipeline. A liquid inlet valve is provided on the liquid inlet tube 230. The valve body of the liquid inlet valve can be disposed on the portion of the liquid inlet tube 230 that extends outside the shielding body 100. Under the control of the liquid inlet valve, the liquid to be tested in the monitoring pipeline is introduced into the sample cavity. A liquid outlet pipe 240 is provided at the bottom of the sample container 200. One end of the liquid outlet pipe 240 communicates with the sample chamber, while the other end extends outside the bottom wall of the shielding body 100. The other end of the liquid outlet pipe 240 is connected to a waste liquid storage tank or a nuclear power plant on-site discharge pipeline. A liquid outlet valve is provided on the liquid outlet pipe 240. The valve body of the liquid outlet valve can be located on the portion of the liquid outlet pipe 240 that extends outside the shielding body 100. When the liquid inlet valve is closed, the liquid to be tested is stored in the sample chamber. When the liquid inlet valve is opened, the liquid inlet pipe 230 can discharge the liquid to be tested from the sample chamber.

[0025] It should be noted that the sample container 200 can be made of any chemically resistant material. For example, the sample container 200 is made of polytetrafluoroethylene (PTFE) to withstand acid and alkaline solutions with a pH value of 1 to 13.

[0026] like Figure 2 and Figure 3 As shown, the detection device 300 is disposed in the groove 210, with the detection end of the detection device 300 facing the bottom wall of the contact groove 210, thereby facing the sample chamber. By being disposed in the groove 210, the detection device 300 shortens the detection distance of the liquid to be tested in the sample chamber, increases the detection area of ​​the detection end of the detection device 300 in the liquid to be tested, and thus improves the detection accuracy of the detection device 300 for the liquid to be tested.

[0027] like Figures 1 to 3 As shown, in some embodiments, the port where the liquid outlet tube 240 communicates with the sample chamber is located in the middle of the bottom wall of the sample chamber, so that the liquid to be tested stored in the sample chamber can be completely discharged through the liquid outlet tube 240 .

[0028] like Figures 1 to 3As shown, in some embodiments, the sample container 200 is further provided with a vent located at the top of the sample container 200, connecting the sample cavity to the external atmosphere to balance the air pressure within the sample cavity and ensure that no residue remains after liquid displacement within the sample cavity. For example, in one example, a vent tube 250 is provided at the top of the sample container 200. One end of the vent tube 250 is connected to the sample cavity, and the other end of the vent tube 250 extends in the height direction to the outside of the shielding body 100. The other end of the vent tube 250 is configured as a vent.

[0029] like Figure 2 and Figure 4 As shown, in some embodiments, the detection device 300 includes a shell 310 and a detector array. The shell 310 is made of aluminum alloy. The shell 310 is placed in the groove 210. The detector array is encapsulated in the shell 310. The detection end of the detector array is facing one end of the shell 310 close to the sample chamber.

[0030] like Figure 2 and Figure 4 As shown, in some embodiments, for the overlapping projection area formed by the detector array on the housing 310 along the height direction, the wall thickness of the housing 310 in this projection area is any value within the range of 0.5 to 1 mm, for example, 0.5 mm, 0.75 mm, or 1 mm. When the thickness of the housing 310 in the projection area of ​​the detector array is within the above range, the thin shell can reduce the attenuation of radioactive rays and improve the detection sensitivity of the detector array.

[0031] like Figure 2 and Figure 4 As shown, in some embodiments, the detector array includes at least four gamma-ray detectors arranged in an array on the detection end plane. For example, the detector array includes four gamma-ray detectors arranged in four quadrants, each measuring 22 mm x 22 mm x 10 mm. The four gamma-ray detectors form a 44 mm x 44 mm detection area on the detection end plane. The gamma-ray detectors are cadmium zinc telluride (CZT) detectors, enabling integrated monitoring of radionuclides in pipeline fluids within nuclear power plants.

[0032] Although some nuclear power plants have attempted to integrate on-site detectors 300 for online nuclide monitoring, this approach has been hindered by inherent limitations of various detectors 300. For example, high-purity germanium detectors typically require liquid nitrogen cooling, requiring maintenance more than once a week. Furthermore, these detectors are bulky, making them difficult to effectively integrate into online monitoring systems. NaI scintillator detectors suffer from poor energy resolution (≥7% @ 662 keV), making them unable to distinguish between gamma rays of similar energies (such as 134Cs and 137Cs), resulting in poor identification of gamma nuclides. Cadmium zinc telluride (CZT) detectors offer the advantages of requiring no cooling and high energy resolution (≤1.5% @ 662 keV). However, their small size (typically crystal size <1 cm³) results in low detection efficiency for liquid samples (<0.1%). Furthermore, they lack shielding for liquid environments, making them unsuitable for direct radioactivity detection in liquids. However, in some embodiments, a CZT detector is used as a gamma-ray detector of the detector array in the embodiment of the present application. The sample container 200 groove 210 structure can be used to expand the crystal sensitive volume of the CZT detector to 20 cm³ in the form of an array, and the shielding body 100 design can be used to reduce the full spectrum background of the CZT detector array to 5.29 cps. While retaining its advantages of small size, no need for cooling, and high energy resolution, its detection accuracy for the liquid to be tested will be improved, so that it can be effectively integrated into the detection equipment to complete the online monitoring of liquid effluents in nuclear power plants and meet the detection limit requirement of ≤1Bq / L in the "Technical Specifications for Radioactive Monitoring of Effluents from Nuclear Power Plants (Trial)".

[0033] like Figure 2 and Figure 4 As shown, in some embodiments, when the detection device 300 is installed in the recess 210, a portion of the housing 310 of the detection device 300 is positioned outside the recess 210. A first vent 311 is provided on the sidewall of the housing 310. Multiple first vents 311 form a grid-like structure of heat dissipation grooves 210 on the sidewall of the housing 310. The heat dissipation grooves 210 may be 2 mm deep and spaced 5 mm apart. Second vents 312 are provided on the top wall of the housing 310 at the end facing away from the sample chamber. Multiple second vents 312 extend along the edge of the top wall to form ventilation holes. A cooling fan is also enclosed within the housing 310, facing the detector array. When in operation, the cooling fan drives airflow into the second vents 312 and out through the first vents 311. This creates a forced convection channel between the second vents 312 on the top wall of the housing 310 and the first vents 311 on the sidewall of the housing 310, ensuring that the operating temperature of the detector array is reduced to below 40°C and that the temperature rise of the detector array remains below 3°C for 24 hours of continuous operation.

[0034] like Figure 2 and Figure 4As shown, in some embodiments, the wall of the shield 100 includes a copper layer, a lead layer, and a stainless steel layer, which are arranged sequentially from the inside out, with the lead layer accounting for greater than 85% of the volume of the shield 100. For example, the wall of the shield 100, from the inside out, comprises a 5 mm thick copper layer, a 30 mm thick lead layer, and a 5 mm thick 304 stainless steel layer. The shield 100 has a shielding efficiency of 99.78% for 500 keV gamma rays, and a full-spectrum background count rate of ≤5.29 cps (energy range 84.5-3000 keV) under typical environmental conditions. The composite shield 100 reduces the environmental background by 12 times.

[0035] like Figures 1 to 3 As shown, in some embodiments, the shielding body 100 includes a shielding box 110 and a top cover 120. The shielding box 110 has a accommodating cavity 220 therein, and the shielding box 110 has an accommodating cavity 220 opening at the top. The accommodating cavity 220 is used to accommodate the sample container 200 and the detection device 300. The shielding box 110 also has a through hole at the bottom for the liquid outlet pipe 240 to extend through. The top cover 120 is installed on the top wall of the shielding box 110 to seal the accommodating cavity 220 opening of the shielding box 110. The top cover 120 is provided with two through holes for the liquid inlet pipe 230 and the vent pipe 250 to pass through, respectively. In addition, a T-shaped maze-like mating sealing structure is provided between the top cover 120 and the opening of the shielding box 110.

[0036] In addition, in some embodiments, a liquid level sensor is further provided in the sample chamber, and the liquid level sensor detects the liquid level height of the liquid to be tested introduced into the sample chamber to obtain the volume ratio of the liquid to be tested in the sample chamber.

[0037] In the second aspect, Figure 5 As shown, the present invention also provides a method for detecting the radioactive activity of a liquid, which is implemented using the detection device in any of the above embodiments, and the detection method includes: Step S1: introducing the liquid to be tested into the sample chamber so that the sample chamber is fully filled with the liquid to be tested; then detecting the liquid to be tested by the detection device 300 to obtain a detection result.

[0038] In step S1, when the detection device 300 includes a gamma-ray detector array, the detection result obtained is the gamma energy spectrum collected by the gamma-ray detector array. The gamma energy spectrum is used to represent the radioactive energy and net radioactive activity count of various nuclides in the liquid to be tested measured by the gamma-ray detector. The net radioactive activity count is the difference between the actual count measured by the detection device 300 and the background count.

[0039] Step S2: Determine the type of radioactive nuclides in the liquid to be tested based on the detection results.

[0040] In step S2, the type of radioactive nuclide in the liquid to be tested is determined based on the radioactive energy corresponding to the characteristic radiation peak in the gamma energy spectrum.

[0041] Step S3: Based on the radioactive nuclide type, determine the detection efficiency of the detection device 300 for each type of radioactive nuclide in the liquid to be detected.

[0042] Since the pre-established detection efficiency scale represents the numerical relationship between the detection efficiency of the detection device 300 for a sample chamber full of the test liquid and the measured radioactivity energy, in step S3, the detection efficiency corresponding to each type of radionuclide is determined from the detection efficiency scale based on the radioactivity energy corresponding to the radionuclide type measured in the test liquid. The detection efficiency scale may be a detection efficiency calibration curve.

[0043] Step S4: obtaining the radioactivity concentration of each type of radionuclide in the liquid to be tested based on the detection time, the detection result, the gamma-ray emission probability corresponding to each type of radionuclide, and the detection efficiency.

[0044] In step S4, based on the volume of the sample chamber, the detection time of the detection device 300 for the liquid to be tested, the detection result, the gamma-ray emission probability corresponding to each type of radionuclide in the liquid to be tested, and the detection efficiency of the detection device 300, the radioactivity concentration of each type of radionuclide is determined according to the relationship of formula (1). The relationship of formula (1) is as follows:

[0045] in, N The net radioactivity count corresponding to each type of radionuclide in the detection results; V is the volume of the sample chamber; t The detection time of the detection device 300 for the liquid to be detected can be adjusted within the range of 1 hour to 24 hours; ε ( E ) is the detection efficiency of the detection device 300 for gamma rays emitted by various types of radionuclides; P λ is the gamma-ray emission probability of various radionuclides.

[0046] like Figure 6 As shown, in some embodiments, in step S3, the process of obtaining the detection efficiency scale of the detection device 300 includes the following steps: S31 . Based on parameter information of the detection device 300 and position information of the detection device 300 relative to the sample chamber, establish an initial detection efficiency scale of the detection device 300 for the liquid loaded in the sample chamber.

[0047] In step S31, a Monte Carlo algorithm is used to simulate and obtain the initial detection efficiency calibration of the detection device 300 for a sample chamber filled with the liquid to be tested, based on the parameters of the detection device 300 and the position of the detection device 300 relative to the sample chamber. The initial detection efficiency calibration includes the numerical relationship between the detection efficiency and the radioactive energy of the nuclide, and can also be represented as an initial detection efficiency calibration curve.

[0048] S32 , obtaining detection efficiency calibration data obtained by the detection device 300 from detecting the standard nuclide liquid loaded in the sample chamber.

[0049] In step S32, the detection efficiency calibration data is obtained by the detection device 300 through a detection experiment of a sample chamber filled with a standard nuclide liquid. Specifically, the standard nuclide source (such as 137 Cs, 60 Co、 54 Mn) is filled into the sample chamber of the detection device, and then the detection device 300 is used to detect the radioactive activity of the standard nuclide liquid. Based on the ratio of the net activity result obtained by detection to the activity of the standard nuclide source in the standard nuclide liquid, the detection efficiency data of the detection device 300 for the tested nuclide is determined. Subsequently, the standard nuclide source injected into the liquid is adjusted, and the above test process is repeated. The test results are summarized to obtain the detection efficiency calibration data of the detection device 300 for multiple radioactive nuclides.

[0050] S33. Determine the detection efficiency scale of the detection device 300 for the liquid loaded in the sample chamber based on the detection efficiency calibration data and the initial detection efficiency scale.

[0051] In step S33, the detection efficiency calibration data and the initial detection efficiency scale are fitted by weighted least squares method to obtain a revised detection efficiency scale. The revised detection efficiency scale is shown in formula (2), and the relationship in formula (2) is as follows:

[0052] in, E The detection device 300 detects the radiation energy of the covered radioactive rays. a 、 b 、 c 、 d 、 e are the parameters of the polynomial fit using the detection efficiency calibration data, K are the dynamic calibration parameters fitted by the detection efficiency calibration data.

[0053] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone familiar with the technology may modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed by the present invention shall still be covered by the claims of the present invention. Anyone familiar with the technology may modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A device for detecting liquid radioactivity, characterized in that: include: A shielding body having an accommodating cavity therein; A sample container is disposed in the accommodating cavity, wherein a groove is disposed on the top of the sample container, a sample cavity is formed in the sample container, a liquid inlet tube is disposed on the top of the sample container, and a liquid outlet tube is disposed on the bottom of the sample container, wherein the liquid inlet tube and the liquid outlet tube are in communication with the sample cavity; A detection device is arranged in the groove, with a detection end of the detection device facing the sample cavity.

2. The detection device according to claim 1, characterized in that The liquid inlet pipe extends to the outside of the shielding body, and is provided with a liquid inlet valve; the liquid outlet pipe is arranged at the middle position of the bottom wall of the sample chamber, and extends out of the bottom of the shielding body in the height direction, and is provided with a liquid outlet valve.

3. The detection device according to claim 1, characterized in that The sample container is also provided with a vent, which is located at the top of the sample container.

4. The detection device according to claim 1, characterized in that The detection device comprises a shell and a detector array. The shell is placed in the groove. The detector array is packaged in the shell. The detection end of the detector array faces one end of the shell close to the sample cavity.

5. The detection device according to claim 4, characterized in that The wall thickness of the detector array at the projection area covered on the shell in the height direction is 0.5-1 mm.

6. The detection device according to claim 4, characterized in that The detector array includes at least four gamma-ray detectors arranged in an array on a detection end plane, and the gamma-ray detectors are CZT detectors.

7. The detection device according to claim 4, characterized in that Part of the shell is located outside the groove, a first vent is provided on the side wall of the shell, a second vent is provided on the top wall of the shell away from the sample chamber, and a cooling fan is also provided in the shell, facing the detector array.

8. The detection device according to claim 1, characterized in that The wall of the shielding body includes a copper layer, a lead layer and a stainless steel layer arranged in sequence from the inside to the outside, and the volume of the lead layer in the shielding body accounts for more than 85%.

9. A method for detecting the radioactivity of a liquid, characterized in that: The detection method is implemented using the detection device according to any one of claims 1 to 8, and the detection method comprises: Obtaining a detection result obtained by a detection device on the liquid to be tested in the sample chamber; Determining the type of radioactive nuclides in the liquid to be tested based on the detection result; Determining the detection efficiency of the detection device for each type of radionuclide in the liquid to be tested based on the type of radionuclide; The radioactivity concentration of each type of radionuclide in the liquid to be tested is obtained based on the detection time, the detection result, the gamma ray emission probability corresponding to each type of radionuclide, and the detection efficiency.

10. The detection method according to claim 9, characterized in that: The steps for obtaining the detection efficiency of various types of radionuclides include: Based on the radioactive energy of the nuclides corresponding to the radioactive nuclides, the detection efficiency corresponding to each type of radionuclide is determined from the detection efficiency scale of the detection device; The process of obtaining the detection efficiency scale includes: Establishing an initial detection efficiency scale of the detection device for the liquid loaded in the sample cavity based on parameter information of the detection device and position information of the detection device relative to the sample cavity, wherein the initial detection efficiency scale includes a numerical relationship between the detection efficiency and the radioactive energy of the nuclide; Acquiring detection efficiency calibration data obtained by the detection device for detecting the standard nuclide liquid loaded in the sample chamber; The detection efficiency scale of the detection device for the liquid loaded in the sample chamber is determined based on the detection efficiency calibration data and the initial detection efficiency scale.

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