Method for determining sorting limit value of radioactive substance

Abstract

The embodiment of the invention provides a method for determining the sorting limit value of a radioactive substance, and the method comprises the following steps: determining a plurality of activity concentration ratios among nuclides in the radioactive substance, and obtaining the calculation boundary activity concentration of each nuclide according to each activity concentration ratio. And preparing a plurality of samples corresponding to each calculated boundary activity concentration. And obtaining the corresponding radioactivity measurement values of each sample at different positions. And obtaining a sorting limit value according to each radioactivity measurement value and each calculated boundary activity concentration. The determination method provided by the embodiment of the invention is relatively low in cost and relatively high in analysis efficiency.

Description

Technical Field

[0001] The present application relates to the technical field of radioactive material processing, and in particular to a method for determining sorting limits of radioactive materials. Background Art

[0002] Radioactive materials are substances containing unstable atomic nuclei that spontaneously decay and emit alpha, beta, and gamma radiation. Their radioactivity decays exponentially over time. These substances are widely found in nuclear facility operations, medical radiation, industrial flaw detection, and other fields. If improperly managed, they can cause irreversible harm to human health and the ecological environment through external or internal radiation exposure. Therefore, the classification and sorting of radioactive materials is a core component of the safe management of radioactive waste.

[0003] In the related art, when radioactive materials are classified and sorted according to their activity concentration, a large number of samples need to be analyzed, resulting in high costs and low analysis efficiency. Summary of the Invention

[0004] In view of this, the main purpose of the embodiments of the present application is to provide a method for determining the sorting limit of radioactive materials with low cost and high analysis efficiency.

[0005] To achieve the above objectives, the technical solution of the embodiment of the present application is implemented as follows:

[0006] The present invention provides a method for determining a sorting limit of radioactive material, the method comprising the following steps:

[0007] determining a plurality of activity concentration ratios between the nuclides in the radioactive material, and obtaining a calculated boundary activity concentration of each nuclide based on each of the activity concentration ratios;

[0008] preparing a plurality of samples corresponding to the calculated boundary activity concentrations;

[0009] Obtaining radioactivity measurement values ​​corresponding to different positions of each sample;

[0010] The sorting limit is obtained based on each of the radioactivity measurement values ​​and each of the calculated boundary activity concentrations.

[0011] In one embodiment, determining a plurality of activity concentration ratios between nuclides in the radioactive material and obtaining a calculated boundary activity concentration of each nuclide according to each activity concentration ratio specifically includes:

[0012] Determine multiple activity concentration ratios between nuclides;

[0013] Obtain the classification activity concentration guidance value corresponding to each nuclide;

[0014] Obtaining, based on the activity concentration ratios, the classified activity concentration guidance values, and a first calculation formula, a calculated boundary activity concentration corresponding to each nuclide of the radioactive material at each activity concentration ratio;

[0015] Wherein, the first calculation formula is:

[0016]

[0017] Among them, C i is the activity concentration of the ith nuclide, Bq / g; C i0 is the classification activity concentration guide value of the i-th nuclide, Bq / g; n is the number of types of the nuclide.

[0018] In one embodiment, the classification activity concentration guidance value includes a clearance limit guidance value, the calculated boundary activity concentration includes the clearance limit boundary activity concentration of the nuclide under the clearance limit guidance value, and the sorting limit includes a radioactive clearance limit; or,

[0019] The classification activity concentration guidance value includes the low level lower limit guidance value, the calculated boundary activity concentration includes the low level lower limit boundary activity concentration of the nuclide under the low level lower limit guidance value, and the sorting limit includes the radioactive low level lower limit value.

[0020] In one embodiment, the radioactive material includes a first nuclide and a second nuclide, and determining a plurality of activity concentration ratios between the nuclides in the radioactive material and obtaining a calculated boundary activity concentration of each nuclide based on each of the activity concentration ratios specifically includes:

[0021] determining a plurality of said activity concentration ratios between said first nuclide and said second nuclide;

[0022] Obtaining a classification activity concentration guidance value for the first nuclide;

[0023] obtaining a classification activity concentration guidance value for the second nuclide;

[0024] According to each of the activity concentration ratios, the classified activity concentration guidance value of the first nuclide, the classified activity concentration guidance value of the second nuclide and the first calculation formula, the calculated boundary activity concentration of the first nuclide and the calculated boundary activity concentration of the second nuclide of the radioactive material at each of the activity concentration ratios are obtained.

[0025] In one embodiment, the preparing a plurality of samples corresponding to the activity-concentration ratios specifically comprises:

[0026] A plurality of samples are arranged according to the calculated boundary activity concentrations of the first nuclides and the calculated boundary activity concentrations of the second nuclides corresponding thereto.

[0027] In one embodiment, before obtaining the radioactivity measurement values ​​corresponding to the samples at different positions, the following steps are included:

[0028] Each of the samples is placed in a container with a measurable area equal to the instrument window area according to the set stacking thickness.

[0029] In one embodiment, the set stacking thickness is greater than or equal to 1.3 cm and less than or equal to 1.7 cm.

[0030] In one embodiment, obtaining the sorting limit value according to each of the radioactivity measurement values ​​and each of the calculated boundary activity concentrations specifically includes:

[0031] Obtaining an average value of the radioactivity measurement values ​​corresponding to different positions of each sample;

[0032] Obtaining a fitting formula according to each of the average values ​​and each of the calculated boundary activity concentrations;

[0033] The sorting limit is obtained according to each of the calculated boundary activity concentrations and the fitting formula.

[0034] In one embodiment, obtaining the sorting limit value according to the calculated boundary activity concentration and the fitting formula specifically includes:

[0035] Obtaining a plurality of fitting values ​​according to the calculated boundary activity concentration of each sample and the fitting formula;

[0036] The sorting limit is the minimum value among the fitting values.

[0037] In one embodiment, the radioactivity measurement value includes at least one of an alpha measurement value, a beta measurement value, and a gamma measurement value.

[0038] The embodiment of the present application provides a method for determining the sorting limit of a radioactive material, comprising the following steps: determining multiple activity concentration ratios between the nuclides in the radioactive material, and obtaining the calculated boundary activity concentration of each nuclide based on each activity concentration ratio. Preparing multiple samples corresponding to each calculated boundary activity concentration. Obtaining the radioactivity measurement value corresponding to each sample at different positions. Obtaining the sorting limit based on each radioactivity measurement value and each calculated boundary activity concentration. By setting multiple activity concentration ratios and preparing samples corresponding to each activity concentration ratio, the sorting limit can be obtained by testing a small amount of samples, thereby improving the efficiency of classifying and sorting radioactive materials and reducing the analysis cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a flow chart of a method for determining a sorting limit value of radioactive material according to the first embodiment of the present application;

[0040] Figure 2 This is a flow chart of a method for determining a sorting limit for radioactive materials according to the second embodiment of the present application. DETAILED DESCRIPTION

[0041] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0042] An embodiment of the present application provides a method for determining the sorting limit of radioactive materials, see Figure 1 and Figure 2 , the determination method includes the following steps:

[0043] Step S1: determining a plurality of activity concentration ratios between nuclides in a radioactive material, and obtaining a calculated boundary activity concentration of each nuclide based on each activity concentration ratio.

[0044] Step S2: preparing a plurality of samples corresponding to each calculated boundary activity concentration.

[0045] Step S3: Obtain the radioactivity measurement values ​​corresponding to different positions of each sample.

[0046] Step S4: Obtain sorting limits based on each radioactivity measurement value and each calculated boundary activity concentration.

[0047] Specifically, radioactive materials refer to materials containing radioactive nuclides that spontaneously decay and release radiation (such as α-rays, β-rays or γ-rays, etc.).

[0048] The radioactivity measurement value will be different depending on the radiation released by the nuclides in the sample.

[0049] Exemplarily, the radioactivity measurement value includes at least one of an alpha measurement value, a beta measurement value, and a gamma measurement value. That is, when a nuclide in the sample emits alpha radiation, the radioactivity measurement value is an alpha measurement value; when a nuclide in the sample emits beta radiation, the radioactivity measurement value is a beta measurement value; and when a nuclide in the sample emits gamma radiation, the radioactivity measurement value is a gamma measurement value. In other words, the type of radioactivity measurement value corresponds to the type of radiation emitted by the nuclide.

[0050] It should be noted that the nuclides in the sample may emit only one type of radiation or multiple types simultaneously. Therefore, depending on the radiation emitted by the nuclides in the sample, the radioactivity measurement value may include only one of the α, β, and γ measurements. Alternatively, it may include two or three of these values ​​simultaneously.

[0051] Activity concentration refers to the activity of nuclides per unit volume or unit mass of radioactive material.

[0052] The activity concentration ratio refers to the ratio between the activity concentrations of different nuclides, which is set according to actual needs. It reflects the proportional relationship between the activity concentrations of different nuclides.

[0053] The calculated boundary activity concentration refers to the activity concentration boundary value of each radionuclide obtained based on the activity concentration ratio, through relevant calculations or in accordance with standard specifications.

[0054] The sample refers to a radioactive sample prepared based on the calculated boundary concentration of each nuclide obtained from the activity concentration ratio.

[0055] Specifically, the number of samples corresponds one-to-one to the number of activity-concentration ratios.

[0056] In other words, for each activity concentration ratio, a set of calculated boundary activity concentrations can be obtained. Each set of calculated boundary activity concentrations includes the calculated boundary activity concentrations of each nuclide at that activity concentration ratio. Subsequently, based on the calculated boundary activity concentrations of each nuclide, a sample containing the corresponding nuclide and having activity concentrations that match the nuclide one-to-one is prepared.

[0057] Multiple locations are selected in the radioactive material sorting site, and the radioactivity measurement value corresponding to each sample at each location is measured respectively.

[0058] It should be noted that there is no limit to the number of locations that can be selected in the radioactive material sorting site, as long as the selected locations can represent the background radiation level of the radioactive material sorting site.

[0059] The method for determining the sorting limit of radioactive material in an embodiment of the present application includes the following steps: determining multiple activity concentration ratios between the nuclides in the radioactive material, and obtaining the calculated boundary activity concentration of each nuclide based on each activity concentration ratio. Preparing multiple samples corresponding to each calculated boundary activity concentration. Obtaining the radioactivity measurement value corresponding to each sample at different positions. Obtaining the sorting limit based on each radioactivity measurement value and each calculated boundary activity concentration. By setting multiple activity concentration ratios and preparing samples corresponding to each activity concentration ratio, the sorting limit can be obtained by testing a small amount of samples, thereby improving the efficiency of classifying and sorting radioactive materials and reducing the analysis cost.

[0060] In one embodiment, determining multiple activity concentration ratios between nuclides in a radioactive material and obtaining a calculated boundary activity concentration of each nuclide based on each activity concentration ratio specifically includes:

[0061] Determine multiple activity concentration ratios between nuclides;

[0062] Obtain the classification activity concentration guidance value corresponding to each nuclide;

[0063] Obtain the calculated boundary activity concentration of the radioactive material corresponding to each nuclide at each activity concentration ratio based on each activity concentration ratio, each classification activity concentration guide value, and the first calculation formula;

[0064] Among them, the first calculation formula is:

[0065]

[0066] Among them, C i is the activity concentration of the ith nuclide, Bq / g; C i0 is the guidance value of the classified activity concentration of the ith nuclide, Bq / g; n is the number of nuclides.

[0067] Specifically, the classified activity concentration guidance value refers to the reference value of nuclides in radioactive materials set according to different application scenarios or safety standards, which is used to determine whether the radioactive materials meet specific safety requirements.

[0068] There are different types of guidance values ​​for classified activity concentrations.

[0069] It is understandable that the types of calculated boundary activity concentrations and the types of sorting limits vary depending on the type of classification activity concentration guidance value.

[0070] For example, the classified activity concentration guidance value includes the clearance limit guidance value, the calculated boundary activity concentration includes the clearance limit boundary activity concentration of the nuclide under the clearance limit guidance value, and the sorting limit includes the radioactive clearance limit.

[0071] For example, the classified activity concentration guidance value includes the low-level lower limit guidance value, the calculated boundary activity concentration includes the low-level lower limit boundary activity concentration of the nuclide under the low-level lower limit guidance value, and the sorting limit includes the radioactive low-level lower limit guidance value.

[0072] The activity concentration guidance values ​​for each category correspond one-to-one to the type of nuclide.

[0073] It should be noted that for the same nuclide, the guidance value of its classification activity concentration is fixed.

[0074] There is no limit on the type and quantity of nuclides contained in radioactive materials.

[0075] For ease of description, the radioactive material in the embodiments of the present application includes a first nuclide and a second nuclide.

[0076] Exemplarily, the radioactive material includes a first nuclide and a second nuclide, and determining a plurality of activity concentration ratios between the nuclides in the radioactive material, and obtaining a calculated boundary activity concentration of each nuclide according to each activity concentration ratio specifically includes:

[0077] determining a plurality of activity concentration ratios between a first nuclide and a second nuclide;

[0078] Obtain the guidance value of the classified activity concentration of the first nuclide;

[0079] Obtain the classification activity concentration guidance value of the second nuclide;

[0080] According to each activity concentration ratio, the classified activity concentration guidance value of the first nuclide, the classified activity concentration guidance value of the second nuclide and the first calculation formula, the calculated boundary activity concentration of the first nuclide and the calculated boundary activity concentration of the second nuclide of the radioactive material at each activity concentration ratio are obtained.

[0081] Specifically, the type of the first nuclide is not limited.

[0082] For example, the first nuclide is 137 Cs.

[0083] For example, the first nuclide is 90 Sr.

[0084] The type of the second nuclide is not limited.

[0085] For example, the second nuclide is 137 Cs.

[0086] For example, the second nuclide is 90 Sr.

[0087] The categorical activity concentration guidance value of the first nuclide refers to the categorical activity concentration guidance value corresponding to the first nuclide.

[0088] For example, when the first nuclide is 137 Cs, the guidance value for the classification activity concentration of the first nuclide refers to the 137 Cs corresponds to the guidance value of the classification activity concentration.

[0089] For example, when the first nuclide is 90 For Sr, the guidance value for the classification activity concentration of the first nuclide refers to the 90 Guidance value for the classification activity concentration corresponding to Sr.

[0090] The categorical activity concentration guidance value of the second nuclide refers to the categorical activity concentration guidance value corresponding to the second nuclide.

[0091] For example, when the second nuclide is 137 Cs, the guidance value for the classification activity concentration of the second nuclide refers to the 137 Cs corresponds to the guidance value of the classification activity concentration.

[0092] For example, when the second nuclide is 90 For Sr, the guidance value for the classification activity concentration of the second nuclide refers to the 90 Guidance value for the classification activity concentration corresponding to Sr.

[0093] The activity concentration ratio between the activity concentration of the first nuclide and the activity concentration of the second nuclide is not limited in magnitude.

[0094] For example, the activity concentration ratio between the activity concentration of the first nuclide and the activity concentration of the second nuclide is greater than 0 and less than or equal to 1. For another example, the activity concentration ratio between the activity concentration of the first nuclide and the activity concentration of the second nuclide is greater than 1.

[0095] It should be noted that when obtaining multiple activity concentration ratios between a first nuclide and a second nuclide, each activity concentration ratio is distributed over a full range: some ratios are greater than 0 and less than 1, simulating scenarios where the activity concentration of the first nuclide is lower than that of the second nuclide; one ratio is equal to 1, simulating scenarios where the activity concentrations of the two nuclides are equal; and the remaining ratios are greater than 1, simulating scenarios where the activity concentration of the first nuclide is higher than that of the second nuclide. Therefore, by using the full range of activity concentration ratios, it is possible to simulate the different relative content relationships of the two nuclides in radioactive materials, comprehensively considering the diversity of nuclide composition in actual radioactive materials, thereby improving the accuracy and reliability of the radioactive material sorting process and effectively reducing the risk of misjudgment due to differences in nuclide ratios in radioactive materials.

[0096] In one embodiment, preparing a plurality of samples corresponding to various activity concentration ratios specifically includes:

[0097] A plurality of samples are arranged based on the calculated boundary activity concentration of each first nuclide and the calculated boundary activity concentration of each second nuclide corresponding thereto.

[0098] Specifically, the value of the activity concentration of the first nuclide in the sample is equal to the value of the calculated boundary activity concentration of the first nuclide, and the value of the activity concentration of the second nuclide is equal to the value of the calculated boundary activity concentration of the second nuclide.

[0099] In one embodiment, before obtaining the radioactivity measurement values ​​corresponding to different positions of each sample, the following steps are included:

[0100] Place each sample in a container with a measurable area equal to the instrument window area according to the set stacking thickness.

[0101] Therefore, by placing the sample in the container according to the set stacking thickness, the consistency and standardization of the sample during measurement are improved, and the measurement error caused by different sample placement methods is reduced.

[0102] Specifically, the set stacking thickness refers to a predetermined stacking height or thickness of the sample in the container.

[0103] There is no limit to the size of the stacking thickness.

[0104] Exemplarily, the stacking thickness is set to be greater than or equal to 1.3 cm and less than or equal to 1.7 cm. For example, the stacking thickness is set to 1.3 cm, 1.5 cm, or 1.7 cm. Maintaining the set thickness within the above range ensures that the intensity of radiation emitted by each nuclide in the sample meets the instrument's measurement requirements, reducing measurement errors caused by excessively thin thickness. Furthermore, it avoids attenuation deviations in radioactivity measurements caused by thick samples, further improving the accuracy of measurement results.

[0105] In one embodiment, obtaining the sorting limit value based on each radioactivity measurement value and each calculated boundary activity concentration specifically includes:

[0106] Obtain the average value of the radioactivity measurement values ​​corresponding to different positions of each sample;

[0107] Obtain the fitting formula based on each average value and each calculated boundary activity concentration;

[0108] The sorting limit is obtained based on the calculated boundary activity concentration and the fitting formula.

[0109] It should be noted that the type of the average value of the radioactivity measurement value is different depending on the type of radiation released by the nuclide in the sample, and the type of the average value of the radioactivity measurement value corresponds to the type of radiation released by the nuclide.

[0110] Exemplarily, the radioactivity measurement values ​​of the sample at each position include α measurement values, β measurement values ​​and γ measurement values, then the average value of each α measurement value, the average value of each β measurement value and the average value of each γ measurement value of the sample at different positions are obtained respectively.

[0111] For ease of description, the radioactivity measurement values ​​in the embodiments of the present application include α measurement values, β measurement values, and γ measurement values.

[0112] The number of average values ​​of the radioactivity measurements corresponds one-to-one to the number of samples. That is, the number of average values ​​of the α measurements is the same as the number of samples, the number of average values ​​of the β measurements is the same as the number of samples, and the number of average values ​​of the γ measurements is the same as the number of samples.

[0113] The fitting formula is obtained based on each average value and each calculated boundary activity concentration, that is, the average value of each α measurement value and each calculated boundary activity concentration are fitted to obtain the fitting formula for α, the average value of each β measurement value and each calculated boundary activity concentration are fitted to obtain the fitting formula for β, and the average value of each γ measurement value and each calculated boundary activity concentration are fitted to obtain the fitting formula for γ.

[0114] There is no restriction on the method of obtaining the sorting limit value according to each calculation boundary activity concentration and fitting formula.

[0115] Exemplarily, obtaining the sorting limit value according to the calculated boundary activity concentration and the fitting formula specifically includes:

[0116] According to the calculated boundary activity concentration of each sample and the fitting formula, a plurality of fitting values ​​are obtained.

[0117] The sorting limit is the minimum of the fitted values.

[0118] Specifically, the calculated boundary activity concentrations of each sample are respectively substituted into the fitting formula for α, the fitting formula for β, and the fitting formula for γ. According to the different types of calculated boundary activity concentrations, multiple fitting values ​​corresponding to the types of calculated boundary activity concentrations are obtained.

[0119] For example, when the calculated boundary activity concentration is the clearance limit boundary activity concentration, multiple fitted values ​​of α clearance limits are obtained by fitting each clearance limit boundary activity concentration with a fitting formula for α. The multiple fitted values ​​of α clearance limits are compared, and the smallest fitted value of α clearance limit is the final α clearance limit. Multiple fitted values ​​of β clearance limits are obtained by fitting each clearance limit boundary activity concentration with a fitting formula for β. The multiple fitted values ​​of β clearance limits are compared, and the smallest fitted value of β clearance limit is the final β clearance limit. Multiple fitted values ​​of γ clearance limits are obtained by fitting each clearance limit boundary activity concentration with a fitting formula for γ. The multiple fitted values ​​of γ clearance limits are compared, and the smallest fitted value of γ clearance limit is the final γ clearance limit.

[0120] For example, when the calculated boundary activity concentration is the lower limit boundary activity concentration of the low level, multiple fitted values ​​of the α lower limit values ​​of the low level are obtained by fitting each lower limit boundary activity concentration with the fitting formula for α. The multiple fitted values ​​of the α lower limit values ​​of the low level are compared, and the smallest fitted value of the α lower limit value of the low level is the final α lower limit value of the low level. Multiple fitted values ​​of the β lower limit values ​​of the low level are obtained by fitting each lower limit boundary activity concentration with the fitting formula for β. The multiple fitted values ​​of the β lower limit values ​​of the low level are compared, and the smallest fitted value of the β lower limit value of the low level is the final β lower limit value of the low level. Multiple fitted values ​​of the γ lower limit values ​​of the low level are obtained by fitting each lower limit boundary activity concentration with the fitting formula for γ. The multiple fitted values ​​of the γ lower limit values ​​of the low level are compared, and the smallest fitted value of the γ lower limit value of the low level is the final γ lower limit value of the low level.

[0121] In a specific embodiment, 10 activity concentration ratios are selected. When the activity concentration ratios are fixed, the clearance limit boundary activity concentrations of each nuclide are calculated according to the first calculation formula. Then, samples corresponding to the clearance limit boundary activity concentrations are configured and placed in a container with a measurable area equal to the instrument window area. The sample stacking thickness in the container is 1.5 cm. 10 locations are selected that can represent the background radiation level of the radioactive material sorting site. At each location, the α measurement value, β measurement value, and γ measurement value of each sample are measured. The average value of the α measurement value, the average value of the β measurement value, and the average value of the γ measurement value of each sample at the 10 locations are calculated and used for later use. The average value of each α measurement value, the average value of each β measurement value, and the average value of each γ measurement value are used to fit the activity concentration to obtain the corresponding fitting formula. Finally, the calculated activity concentrations of the clearance limits of each nuclide are substituted into the fitting formula, and the minimum value among the fitted values ​​of the α clearance limit is selected as the α clearance level, the minimum value among the fitted values ​​of the β clearance limit is selected as the β clearance level, and the minimum value among the fitted values ​​of the γ clearance limit is selected as the γ clearance level.

[0122] In one specific embodiment, 10 activity concentration ratios are selected. When the activity concentration ratios are fixed, the activity concentration at the lower limit of the low-level radiation level for each nuclide is calculated according to the first calculation formula. Then, a sample corresponding to the activity concentration at the lower limit of the low-level radiation level is arranged and placed in a container with a measurable area equal to the area of ​​the instrument's window. The sample is deposited to a thickness of 1.5 cm in the container. Ten locations are selected that represent the background radiation level of the radioactive material sorting site. The α, β, and γ values ​​of each sample are measured at each location. The average of the α, β, and γ values ​​of each sample at the 10 locations is calculated and used for future reference. The average of the α, β, and γ values ​​is used to fit the activity concentration, resulting in a corresponding fitting formula. Finally, the calculated activity concentration of the lower limit of the low level of each nuclide is substituted into the fitting formula, and the minimum value among the fitted values ​​of the α lower limit of the low level is selected as the α lower limit of the low level, the minimum value among the fitted values ​​of the β lower limit of the low level is selected as the β lower limit of the low level, and the minimum value among the fitted values ​​of the γ lower limit of the low level is selected as the γ lower limit of the low level.

[0123] In the description of this application, the descriptions with reference to the terms "in one embodiment", "in some embodiments", "in a specific embodiment", or "exemplary" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiments of the present application. In this application, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, those skilled in the art can combine different embodiments or examples described in this application and features of different embodiments or examples without contradiction.

[0124] The above description is merely a preferred embodiment of the present application and is not intended to limit the present application. Those skilled in the art will readily appreciate that various modifications and variations are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application are intended to be within the scope of protection of the present application.

Claims

1. A method for determining a sorting limit of radioactive material, characterized in that: The determination method comprises the following steps: determining a plurality of activity concentration ratios between the nuclides in the radioactive material, and obtaining a calculated boundary activity concentration of each nuclide based on each of the activity concentration ratios; preparing a plurality of samples corresponding to the calculated boundary activity concentrations; Obtaining radioactivity measurement values ​​corresponding to different positions of each sample; The sorting limit is obtained based on each of the radioactivity measurement values ​​and each of the calculated boundary activity concentrations.

2. The determination method according to claim 1, characterized in that Determining a plurality of activity concentration ratios between the nuclides in the radioactive material and obtaining the calculated boundary activity concentration of each nuclide according to each of the activity concentration ratios specifically includes: Determine multiple activity concentration ratios between nuclides; Obtain the classification activity concentration guidance value corresponding to each nuclide; Obtaining, based on the activity concentration ratios, the classified activity concentration guidance values, and a first calculation formula, a calculated boundary activity concentration corresponding to each nuclide of the radioactive material at each activity concentration ratio; Wherein, the first calculation formula is: Among them, C i is the activity concentration of the ith nuclide, Bq / g; C i0 is the classification activity concentration guide value of the i-th nuclide, Bq / g; n is the number of types of the nuclide.

3. The determination method according to claim 2, characterized in that: The classification activity concentration guidance value includes a clearance limit guidance value, the calculated boundary activity concentration includes the clearance limit boundary activity concentration of the nuclide under the clearance limit guidance value, and the sorting limit includes a radioactive clearance limit; or, The classification activity concentration guidance value includes the low level lower limit guidance value, the calculated boundary activity concentration includes the low level lower limit boundary activity concentration of the nuclide under the low level lower limit guidance value, and the sorting limit includes the radioactive low level lower limit value.

4. The determination method according to claim 2 or 3, characterized in that: The radioactive material includes a first nuclide and a second nuclide, and determining a plurality of activity concentration ratios between the nuclides in the radioactive material and obtaining a calculated boundary activity concentration of each nuclide according to each activity concentration ratio specifically includes: determining a plurality of said activity concentration ratios between said first nuclide and said second nuclide; Obtaining a classification activity concentration guidance value for the first nuclide; obtaining a classification activity concentration guidance value for the second nuclide; According to each of the activity concentration ratios, the classified activity concentration guidance value of the first nuclide, the classified activity concentration guidance value of the second nuclide and the first calculation formula, the calculated boundary activity concentration of the first nuclide and the calculated boundary activity concentration of the second nuclide of the radioactive material at each of the activity concentration ratios are obtained.

5. The determination method according to claim 4, characterized in that: The preparing of a plurality of samples corresponding to the activity concentration ratios specifically comprises: A plurality of samples are arranged according to the calculated boundary activity concentrations of the first nuclides and the calculated boundary activity concentrations of the second nuclides corresponding thereto.

6. The determination method according to claim 5, characterized in that: Before obtaining the radioactivity measurement values ​​corresponding to the samples at different positions, the following steps are included: Each of the samples is placed in a container with a measurable area equal to the instrument window area according to the set stacking thickness.

7. The determination method according to claim 6, characterized in that: The set stacking thickness is greater than or equal to 1.3 cm and less than or equal to 1.7 cm.

8. The determination method according to any one of claims 1 to 3, characterized in that: The obtaining of the sorting limit value according to each of the radioactivity measurement values ​​and each of the calculated boundary activity concentrations specifically includes: Obtaining an average value of the radioactivity measurement values ​​corresponding to different positions of each sample; Obtaining a fitting formula according to each of the average values ​​and each of the calculated boundary activity concentrations; The sorting limit is obtained according to each of the calculated boundary activity concentrations and the fitting formula.

9. The determination method according to claim 8, characterized in that: The obtaining of the sorting limit value according to the calculated boundary activity concentration and the fitting formula specifically includes: Obtaining a plurality of fitting values ​​according to the calculated boundary activity concentration of each sample and the fitting formula; The sorting limit is the minimum value among the fitting values.

10. The determination method according to any one of claims 1 to 3, characterized in that: The radioactivity measurement value includes at least one of an alpha measurement value, a beta measurement value, and a gamma measurement value.

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