Method for determining sorting limit value of radioactive substance

Abstract

The embodiment of the invention provides a method for determining a sorting limit value of a radioactive substance. The method comprises the following steps: acquiring activity concentration of each nuclide contained in the radioactive substance and a classification activity concentration guide value corresponding to each nuclide; and obtaining the sorting limit total radioactivity specific activity according to each activity concentration and each classification activity concentration guide value. According to the determination method provided by the embodiment of the invention, the classification sorting efficiency of the radioactive substances can be improved.

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 treatment, 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 their safe management.

[0003] In the related art, when radioactive materials are classified and sorted using the activity concentration of nuclides, the sample size for the analysis of the activity concentration of nuclides is large and time-consuming, resulting in low efficiency in the classification and sorting of radioactive materials. 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 higher efficiency.

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

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

[0007] Obtaining the activity concentration of each nuclide contained in the radioactive material and the classified activity concentration guidance value corresponding to each nuclide;

[0008] The sorting limit total radioactive specific activity is obtained based on each of the activity concentrations and each of the classification activity concentration guidance values.

[0009] In one embodiment, the radioactive material includes a first nuclide and a second nuclide, and the determination method includes:

[0010] Obtaining a first nuclide activity concentration and a first nuclide classification activity concentration guidance value of the first nuclide, and obtaining a second nuclide activity concentration and a second nuclide classification activity concentration guidance value of the second nuclide;

[0011] The sorting limit total radioactive specific activity is obtained according to the first nuclide activity concentration, the first nuclide classification activity concentration guide value, the second nuclide activity concentration, and the second nuclide classification activity concentration guide value.

[0012] In one embodiment, the determination method includes:

[0013] Determining the sorting limit total specific activity according to the first nuclide activity concentration, the first nuclide classification activity concentration guide value, the second nuclide activity concentration, the second nuclide classification activity concentration guide value, and a first relationship;

[0014] Wherein, the first relational expression is:

[0015]

[0016] Wherein, x is the total radioactive specific activity of the sorting limit, p is the ratio of the second nuclide classification activity concentration guidance value to the first nuclide classification activity concentration guidance value, b1 is the first nuclide classification activity concentration guidance value, and m is the ratio of the second nuclide activity concentration to the first nuclide activity concentration.

[0017] In one embodiment, determining the sorting limit total specific activity according to the first nuclide activity concentration, the first nuclide classification activity concentration guide value, the second nuclide activity concentration, the second nuclide classification activity concentration guide value, and the first relationship specifically includes:

[0018] determining a first nuclide boundary activity concentration and a second nuclide boundary activity concentration based on the first nuclide activity concentration, the first nuclide classification activity concentration guide value, the second nuclide activity concentration, and the second nuclide classification activity concentration guide value;

[0019] determining the first relationship according to the first nuclide boundary activity concentration and the second nuclide boundary activity concentration;

[0020] The sorting limit total radioactive specific activity is obtained according to the ratio of the second nuclide activity concentration to the first nuclide activity concentration, the ratio of the second nuclide classification activity concentration guidance value to the first nuclide classification activity concentration guidance value, the first nuclide classification activity concentration guidance value and the first relationship.

[0021] In one embodiment, determining the first nuclide boundary activity concentration and the second nuclide boundary activity concentration based on the first nuclide activity concentration, the first nuclide classification activity concentration guide value, the second nuclide activity concentration, and the second nuclide classification activity concentration guide value specifically includes:

[0022] determining a ratio of the second nuclide activity concentration to the first nuclide activity concentration;

[0023] determining the first nuclide boundary activity concentration and the second nuclide boundary activity concentration according to a ratio of the second nuclide activity concentration to the first nuclide activity concentration, the first nuclide classification activity concentration guide value, the second nuclide classification activity concentration guide value, and a second relationship;

[0024] The second relational expression is:

[0025]

[0026] Wherein, a1 is the first nuclide boundary activity concentration, a2 is the second nuclide boundary activity concentration, a2=m·a1, m is the ratio of the second nuclide activity concentration to the first nuclide activity concentration, b1 is the first nuclide classification activity concentration guidance value, and b2 is the second nuclide classification activity concentration guidance value.

[0027] In one embodiment, obtaining the activity concentration of each nuclide contained in the radioactive material and the classified activity concentration guidance value corresponding to each nuclide specifically includes:

[0028] performing nuclide sampling and analysis on the radioactive material to obtain the activity concentration of each nuclide;

[0029] The corresponding classification activity concentration guidance value is obtained according to each of the nuclides.

[0030] In one embodiment, the sorting-limited total radioactive specific activity includes the total alpha sorting-limited specific activity or the total beta sorting-limited specific activity.

[0031] In one embodiment, the classification activity concentration guidance value includes a clearance limit guidance value, and the sorting limit total radioactivity specific activity includes a total radioactivity clearance limit value.

[0032] In one embodiment, the classification activity concentration guidance value includes a low-level lower limit guidance value, and the sorting limit total radioactive specific activity includes a total radioactive low-level lower limit value.

[0033] In one embodiment, the classified activity concentration guidance value is determined according to the national standard "Activity Concentration of Radionuclides in Materials Exempt from Radiation Protection Regulation".

[0034] The present application provides a method for determining sorting limits for radioactive materials, comprising the following steps: obtaining the activity concentration of each nuclide contained in the radioactive material and the corresponding classification activity concentration guideline value for each nuclide; and obtaining the total specific activity within the sorting limit based on the activity concentrations and the classification activity concentration guideline values. This reduces the workload and time required for sampling and measurement, thereby improving the efficiency of radioactive material sorting. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] 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;

[0036] Figure 2This 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

[0037] 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.

[0038] An embodiment of the present application provides a method for determining the sorting limit of radioactive materials, see Figure 1 , the determination method includes the following steps:

[0039] Step S1: Obtain the activity concentration of each nuclide contained in the radioactive material and the classified activity concentration guidance value corresponding to each nuclide.

[0040] Step S2: Obtain the total radioactivity specific activity of the sorting limit according to each activity concentration and the activity concentration guide value of each classification.

[0041] Specifically, radioactive materials refer to materials containing nuclides that spontaneously decay and release radiation (such as α-rays, β-rays or γ-rays).

[0042] There is no limit on the type and quantity of nuclides contained in radioactive materials.

[0043] For ease of description, the radioactive material in the embodiments of the present application includes a first nuclide and a second nuclide.

[0044] Illustratively, the radioactive material includes a first nuclide and a second nuclide, and the determination method includes:

[0045] Obtaining a first nuclide activity concentration and a first nuclide classification activity concentration guidance value of a first nuclide, and obtaining a second nuclide activity concentration and a second nuclide classification activity concentration guidance value of a second nuclide;

[0046] The total radioactive specific activity of the sorting limit is obtained based on the activity concentration of the first nuclide, the guidance value of the first nuclide classification activity concentration, the activity concentration of the second nuclide, and the guidance value of the second nuclide classification activity concentration.

[0047] Specifically, the type of the first nuclide is not limited.

[0048] For example, the first nuclide is 137 Cs.

[0049] For example, the first nuclide is 90 Sr.

[0050] The type of the second nuclide is not limited.

[0051] For example, the second nuclide is 137 Cs.

[0052] For example, the second nuclide is 90 Sr.

[0053] Activity concentration refers to the activity of nuclides per unit volume or unit mass of radioactive material.

[0054] 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.

[0055] There are different types of guidance values ​​for classified activity concentrations.

[0056] For example, guidance values ​​for classified activity concentrations include guidance values ​​for clearance limits.

[0057] For example, the guidance values ​​for classified activity concentrations include guidance values ​​for the lower limit of low radiation levels.

[0058] There is no restriction on the method of determining the guidance value of classification activity concentration.

[0059] Illustratively, the classified activity concentration guidance value is determined according to the national standard "Activity Concentration of Radionuclides in Materials Exempted from Radiation Protection Regulation".

[0060] The sorting limit total radioactivity refers to the sum of the boundary activity concentrations of each nuclide in the radioactive material.

[0061] The sorting limit of total radioactive specific activity varies according to the type of radiation released from the radioactive material.

[0062] For example, the sorting-limited total radioactive specific activity includes the total alpha sorting-limited specific activity or the total beta sorting-limited specific activity.

[0063] It can be understood that the types of the sorting limit total radioactive specific activity are different depending on the type of the classified activity concentration guidance value, and the types of the classified activity concentration guidance value correspond to the types of the sorting limit total radioactive specific activity.

[0064] For example, the classified activity concentration guidance value is the clearance limit guidance value, and the sorting limit total specific activity is the total radioactive clearance limit. That is, depending on the radiation released by the radioactive material, when the classified activity concentration guidance value is the clearance limit guidance value, the sorting limit total specific activity can be the total alpha clearance limit, or, of course, the total beta clearance limit.

[0065] For example, the classified activity concentration guidance value is the lower limit guidance value for low-level radiation, and the sorting limit total specific activity is the lower limit for the total low-level radiation. That is, depending on the radiation released by the radioactive material, when the classified activity concentration guidance value is the lower limit guidance value for low-level radiation, the sorting limit total specific activity can be the lower limit for the total alpha low-level radiation, or, of course, the lower limit for the total beta low-level radiation.

[0066] There is no limit to the method of obtaining the activity concentration of each nuclide contained in the radioactive material and the classification activity concentration guidance value corresponding to each nuclide.

[0067] Exemplarily, radioactive material is sampled and analyzed for nuclides to obtain the activity concentration of each nuclide; and corresponding classified activity concentration guidance values ​​are obtained based on each nuclide.

[0068] It should be noted that in related technologies, when using activity concentration to classify and sort radioactive materials, it is necessary to measure the activity concentration of multiple samples in order to classify and sort the materials. However, this method results in a large and time-consuming sampling and measurement workload, which in turn leads to low efficiency in the classification and sorting of radioactive materials.

[0069] The method for determining the sorting limit of radioactive materials in the embodiment of the present application includes the following steps: obtaining the activity concentration of each nuclide contained in the radioactive material and the classification activity concentration guidance value corresponding to each nuclide. According to each activity concentration and each classification activity concentration guidance value, the total radioactive specific activity of the sorting limit is obtained. Because the ratio between the activity concentrations of each nuclide contained in the radioactive material in the same source term is the same, the total radioactive specific activity of the sorting limit can be determined by performing a nuclide analysis on the radioactive material to obtain the ratio of the activity concentrations of the nuclides, combined with the classification activity concentration guidance value corresponding to each nuclide. This can reduce the workload and time of sampling and measurement, thereby improving the efficiency of sorting and sorting radioactive materials.

[0070] In one embodiment, please refer to Figure 2 , the determination methods include:

[0071] Determining the sorting limit total specific activity based on the first nuclide activity concentration, the first nuclide classification activity concentration guidance value, the second nuclide activity concentration, the second nuclide classification activity concentration guidance value, and the first relationship;

[0072] Among them, the first relationship is:

[0073]

[0074] Where x is the total specific activity within the sorting limit, p is the ratio of the second nuclide classification activity concentration guidance value to the first nuclide classification activity concentration guidance value, b1 is the first nuclide classification activity concentration guidance value, and m is the ratio of the second nuclide activity concentration to the first nuclide activity concentration. Therefore, by measuring the activity concentration of each nuclide in a radioactive material and consulting the corresponding classification activity concentration guidance value for each nuclide to obtain the total specific activity within the sorting limit, the workload and time of sampling and measurement are reduced, thereby improving the efficiency of radioactive material sorting.

[0075] Specifically, the first nuclide activity concentration refers to the activity concentration corresponding to the first nuclide in the radioactive material.

[0076] The first nuclide classification activity concentration guidance value refers to the classification activity concentration guidance value corresponding to the first nuclide.

[0077] The second nuclide activity concentration refers to the activity concentration corresponding to the second nuclide in the radioactive material.

[0078] The second nuclide classification activity concentration guidance value refers to the classification activity concentration guidance value corresponding to the second nuclide.

[0079] It should be noted that the guidance values ​​for the activity concentration of radionuclides in radioactive materials are readily available. Furthermore, for large quantities of radioactive materials generated from the same source, m is constant. Therefore, for dual-nuclide radioactive materials with different guidance values ​​for activity concentration, the total specific activity within the sorting limit can be determined using the first equation after a single sampling and nuclide analysis. This reduces the workload and time required for sampling and measurement, thereby improving the efficiency of radioactive material sorting.

[0080] In one embodiment, determining the sorting limit total specific activity based on the first nuclide activity concentration, the first nuclide classification activity concentration guide value, the second nuclide activity concentration, the second nuclide classification activity concentration guide value, and the first relationship specifically includes:

[0081] determining a first nuclide boundary activity concentration and a second nuclide boundary activity concentration based on the first nuclide activity concentration, the first nuclide classification activity concentration guide value, the second nuclide activity concentration, and the second nuclide classification activity concentration guide value;

[0082] Determining a first relationship according to the first nuclide boundary activity concentration and the second nuclide boundary activity concentration;

[0083] The sorting limit total radioactive specific activity is obtained based on the ratio of the second nuclide activity concentration to the first nuclide activity concentration, the ratio of the second nuclide classification activity concentration guidance value to the first nuclide classification activity concentration guidance value, the first nuclide classification activity concentration guidance value and the first relationship.

[0084] Specifically, by sampling and analyzing dual-nuclide radioactive material, the activity concentration of the first nuclide and the activity concentration of the second nuclide are obtained, and the first nuclide classification activity concentration guidance value and the second nuclide classification activity concentration guidance value are consulted. Subsequently, based on the first nuclide activity concentration, the first nuclide classification activity concentration guidance value, the second nuclide activity concentration, and the second nuclide classification activity concentration guidance value, the boundary activity concentrations of the first nuclide and the second nuclide are determined, respectively, to obtain the first nuclide boundary activity concentration and the second nuclide boundary activity concentration. Next, based on the determined first nuclide boundary activity concentration and the second nuclide boundary activity concentration, a first relationship is derived. Finally, the total specific activity of the radioactive material, the sorting limit, is calculated using the first relationship, thereby achieving a quantitative assessment of the overall radioactivity level of the radioactive material.

[0085] There is no limitation on the method for obtaining the first nuclide boundary activity concentration and the second nuclide boundary activity concentration.

[0086] Illustratively, determining the first nuclide boundary activity concentration and the second nuclide boundary activity concentration according to the first nuclide activity concentration, the first nuclide classification activity concentration guide value, the second nuclide activity concentration, and the second nuclide classification activity concentration guide value specifically includes:

[0087] The ratio of the activity concentration of the second nuclide to the activity concentration of the first nuclide is determined.

[0088] The first nuclide boundary activity concentration and the second nuclide boundary activity concentration are determined according to the ratio of the second nuclide activity concentration to the first nuclide activity concentration, the first nuclide classification activity concentration guide value, the second nuclide classification activity concentration guide value and the second relationship.

[0089] The second relationship is:

[0090]

[0091] Where a1 is the boundary activity concentration of the first nuclide, a2 is the boundary activity concentration of the second nuclide, a2 = m·a1, m is the ratio of the activity concentration of the second nuclide to the activity concentration of the first nuclide, b1 is the guidance value of the classification activity concentration of the first nuclide, and b2 is the guidance value of the classification activity concentration of the second nuclide.

[0092] Specifically, due to the large amount of radioactive material generated by the same source term, the ratio of the activity concentration of the first nuclide to the activity concentration of the second nuclide is constant. That is, because the ratio of the activity concentration of the second nuclide to the activity concentration of the first nuclide is equal to the ratio of the activity concentration of the second nuclide boundary to the activity concentration of the first nuclide boundary, the proportional relationship between the activity concentration of the second nuclide boundary and the activity concentration of the first nuclide boundary can be derived based on the ratio of the activity concentration of the second nuclide to the activity concentration of the first nuclide. Subsequently, based on the proportional relationship between the activity concentration of the second nuclide boundary and the activity concentration of the first nuclide boundary, the guidance value for the activity concentration of the first nuclide classification, the guidance value for the activity concentration of the second nuclide classification, and the second relationship, the activity concentration of the first nuclide boundary and the activity concentration of the second nuclide boundary can be derived.

[0093] There is no limitation on the method of determining the first relational expression.

[0094] For example, for the second relation Perform the common denominator and get the third relation Substituting the fourth relational expression (a1+a2)·(b1+b2)=a1·b1+a1·b2+a2·b1+a2·b2 into the third relational expression, we obtain (Formula 5), ​​let a1+a2=x (Formula 6), and according to Formula 5, we can get (Formula 7). Let a1 = y, a2 = m·y, b2 = p·b1, and according to Formula 7, we can get x = y·(1+m) (Formula 8), Finally, the first relational expression can be obtained according to Expressions 8 and 9.

[0095] In one embodiment, the radioactive material contains 137 Cs and 90 Sr two nuclides, by sampling and performing nuclide analysis, we can get 137 The activity concentration of Cs is 400Bq / g, 90 The activity concentration of Sr is 500Bq / g, 137 Cs and 90 The guidance value of the release limit of Sr is determined by Table 1.

[0096] Table 1 137 Cs, 90 Sr release limit guidance value (Bq / g)

[0097] Nuclide name Release limit <![CDATA[ 137 Cs]]> 0.1 <![CDATA[ 90 Sr]]> 1

[0098] According to the first relationship, we can get:

[0099] The total beta clearance limit for radioactive materials = 0.2Bq / g.

[0100] In one embodiment, the radioactive material contains 137Cs and 90 Sr two nuclides, by sampling and performing nuclide analysis, we can get 137 The activity concentration of Cs is 400Bq / g, 90 The activity concentration of Sr is 500Bq / g, 137 Cs and 90 The lower limit guidance value of Sr low level is determined by Table 2.

[0101] Table 2 137 Cs, 90 Sr low-level radiation lower limit guidance value (Bq / g)

[0102] Nuclide name Lower limit of low level <![CDATA[ 137 Cs]]> 10 <![CDATA[ 90 Sr]]> 100

[0103] According to the first relationship, we can get:

[0104] The lower limit of the total low-beta level of radioactive materials is 20Bq / g.

[0105] 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.

[0106] 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: Obtaining the activity concentration of each nuclide contained in the radioactive material and the classified activity concentration guidance value corresponding to each nuclide; The sorting limit total radioactive specific activity is obtained based on each of the activity concentrations and each of the classification activity concentration guidance values.

2. The determination method according to claim 1, characterized in that The radioactive material includes a first nuclide and a second nuclide, and the determination method includes: Obtaining a first nuclide activity concentration and a first nuclide classification activity concentration guidance value of the first nuclide, and obtaining a second nuclide activity concentration and a second nuclide classification activity concentration guidance value of the second nuclide; The sorting limit total radioactive specific activity is obtained according to the first nuclide activity concentration, the first nuclide classification activity concentration guide value, the second nuclide activity concentration, and the second nuclide classification activity concentration guide value.

3. The determination method according to claim 2, characterized in that: The determination method includes: Determining the sorting limit total specific activity according to the first nuclide activity concentration, the first nuclide classification activity concentration guide value, the second nuclide activity concentration, the second nuclide classification activity concentration guide value, and a first relationship; Wherein, the first relational expression is: Wherein, x is the total radioactive specific activity of the sorting limit, p is the ratio of the second nuclide classification activity concentration guidance value to the first nuclide classification activity concentration guidance value, b1 is the first nuclide classification activity concentration guidance value, and m is the ratio of the second nuclide activity concentration to the first nuclide activity concentration.

4. The determination method according to claim 3, characterized in that: Determining the sorting limit total specific activity according to the first nuclide activity concentration, the first nuclide classification activity concentration guide value, the second nuclide activity concentration, the second nuclide classification activity concentration guide value, and the first relationship specifically includes: determining a first nuclide boundary activity concentration and a second nuclide boundary activity concentration based on the first nuclide activity concentration, the first nuclide classification activity concentration guide value, the second nuclide activity concentration, and the second nuclide classification activity concentration guide value; determining the first relationship according to the first nuclide boundary activity concentration and the second nuclide boundary activity concentration; The sorting limit total radioactive specific activity is obtained according to the ratio of the second nuclide activity concentration to the first nuclide activity concentration, the ratio of the second nuclide classification activity concentration guidance value to the first nuclide classification activity concentration guidance value, the first nuclide classification activity concentration guidance value and the first relationship.

5. The determination method according to claim 4, characterized in that: The determining of the first nuclide boundary activity concentration and the second nuclide boundary activity concentration according to the first nuclide activity concentration, the first nuclide classification activity concentration guide value, the second nuclide activity concentration, and the second nuclide classification activity concentration guide value specifically includes: determining a ratio of the second nuclide activity concentration to the first nuclide activity concentration; determining the first nuclide boundary activity concentration and the second nuclide boundary activity concentration according to a ratio of the second nuclide activity concentration to the first nuclide activity concentration, the first nuclide classification activity concentration guide value, the second nuclide classification activity concentration guide value, and a second relationship; The second relational expression is: Wherein, a1 is the first nuclide boundary activity concentration, a2 is the second nuclide boundary activity concentration, a2=m·a1, m is the ratio of the second nuclide activity concentration to the first nuclide activity concentration, b1 is the first nuclide classification activity concentration guidance value, and b2 is the second nuclide classification activity concentration guidance value.

6. The determination method according to any one of claims 1 to 5, characterized in that: The obtaining of the activity concentration of each nuclide contained in the radioactive material and the classified activity concentration guidance value corresponding to each nuclide specifically includes: performing nuclide sampling and analysis on the radioactive material to obtain the activity concentration of each nuclide; The corresponding classification activity concentration guidance value is obtained according to each of the nuclides.

7. The determination method according to any one of claims 1 to 5, characterized in that: The sorting limit total radioactive specific activity includes the total α sorting limit specific activity or the total β sorting limit specific activity.

8. The determination method according to any one of claims 1 to 5, characterized in that: The classification activity concentration guidance value includes the clearance limit guidance value, and the sorting limit total radioactive specific activity includes the total radioactive clearance limit.

9. The determination method according to any one of claims 1 to 5, characterized in that: The classification activity concentration guidance value includes the low-level lower limit guidance value, and the sorting limit total radioactive specific activity includes the total radioactive low-level lower limit value.

10. The determination method according to any one of claims 1 to 5, characterized in that: The classification activity concentration guidance value is determined in accordance with the national standard "Activity Concentration of Radioactive Nuclides in Materials Exempt from Radiation Protection Regulation".

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