Method for simultaneously measuring ages of two models of uranium material

Abstract

The invention provides a method for simultaneously measuring ages of two models of a uranium material. The method comprises the following steps: preparing a 233Pa diluent; measuring the concentration of the 233Pa diluent; measuring the atomic numbers N1'and N1 of 234 U and 235 U in the uranium material to be measured; adding a first amount of 233 Pa diluent and a second amount of 229 Th diluent with known concentration into the uranium material to be detected to obtain a uranium sample to be separated; separating a Pa sample and a Th sample from the uranium sample to be separated by using an AG1-X8 resin column; measuring 233 Pa / 231 Pa in the Pa sample and 229 Th / 230 Th in the Th sample; the method comprises the steps of calculating the number of atoms N3 of 231Pa and the number of atoms N2'of 230Th in a uranium material to be measured, and calculating the age of the uranium material to be measured according to the formula (1) and the formula (2). According to the method, the age of the 230Th-234U model and the age of the 231Pa-235U model can be measured at the same time, the use amount of the uranium material can be reduced, the age obtained through the two models has comparability, and the method can be used for evaluating the accuracy of age measurement, and the formula (1) and the formula (2) are shown in the description.

Description

Technical Field

[0001] This application relates to the field of radioactive material analysis technology, specifically to a method for simultaneously measuring the ages of two models of uranium material. Background Technology In the areas of radioactive material management, supervision, compliance verification, and source tracing analysis, there is a need to develop high-precision and highly sensitive technologies for measuring the age of radioactive materials. Age is the first parameter that needs to be measured when tracing the history of these materials. Age measurement technology will play a crucial role in determining the compliance of radioactive materials, providing important parameters for source tracing analysis.

[0002] Therefore, the development of uranium material age measurement technology is of great significance, and there is a need to provide an effective method for measuring the age of uranium materials. Summary of the Invention

[0003] In view of this, the purpose of this application is to provide a method for measuring the age of uranium materials, which can simultaneously perform... 230 Th- 234 U and 231 Pa- 235 Measuring the age using both models can reduce the amount of uranium material used, shorten the experimental process and time, and the ages obtained from the two models are comparable, which can be used to evaluate the accuracy of the measured age and obtain more information on the production process of uranium material.

[0004] This application provides a method for simultaneously measuring the ages of two models of uranium material, the method comprising: S1: Preparation 233 Pa diluent; S2: Measure the 233 Pa diluent concentration; S3: Measuring the uranium material to be tested 234 Number of atoms of U N 1 ’ and 235 Number of atoms of U N 1; S4: Add the first amount of uranium material to be tested. 233 Pa diluent and second amount 229 Th diluent, to obtain the uranium sample to be separated, wherein... 229 The concentration of the diluent is known; S5: Use an AG1-X8 resin column to separate the Pa and Th samples from the uranium sample to be separated; S6: Measure the Pa content in the separated Pa sample. 233 Pa / 231 Pa isotope ratio and the Th sample obtained from the separation229 Th / 230 Th isotope ratios; S7: Based on the measurements obtained in step S2 233 The concentration of Pa diluent, added in step S4 233 The first amount of Pa diluent and the amount measured in step S6 233 Pa / 231 Pa isotope ratios were calculated to obtain the content of the uranium material to be tested. 231 number of atoms of Pa N 3; S8: Based on known... 229 The concentration of the diluent, added in step S4 229 The second amount of Th diluent and the amount measured in step S6 229 Th / 230 The Th isotope ratio was used to calculate the content of th in the uranium material being tested. 230 Number of Th atoms N 2 ’ ; S9: Calculate according to formula (1) 230 Th- 234 The age of the uranium material to be tested obtained from the U-model; Formula (1), In formula (1), t' indicates by 230 Th- 234 Age of uranium material obtained by the U model λ1' represents 234 The decay constant of U, λ2' represents 230 The decay constant of Th, N2' indicates that uranium material contains 230 The number of atoms of Th N1' indicates that uranium material contains 234 The number of atoms of U N2' / N1' indicates the uranium material in 230 Th / 234 U atom ratio; S10: Calculate according to formula (2) 231 Pa- 235 The age of the uranium material to be tested obtained from the U-model; Formula (2), In formula (2), t represents by 231 Pa- 235 Age of uranium material obtained by the U model λ1 represents235 The decay constant of U, λ3 represents 231 decay constant of Pa N3 indicates that uranium material contains 231 The number of atoms in Pa. N1 indicates that uranium material contains 235 The number of atoms of U N3 / N1 indicates that in uranium materials... 231 Pa / 235 U atom number ratio.

[0005] In some implementations, preparation 233 Step S1 for Pa diluent includes the following sub-steps: S11: Provides the initial Np solution; S12: Using hydrazine hydrate as a reducing agent, the Np in the initial Np solution is reduced under a temperature holding condition of 70°C to 90°C. 6+ and Np 5+ Restore to Np 4+ The valence state of Np is adjusted to Np. 4+ Reduced Np solution; S13: Separate from the reduced Np solution 233 Pa, obtained 233 Pa diluent.

[0006] In some embodiments, in step S13, an HPQ resin column is used with an aqueous nitric acid solution as the eluent to separate the Np from the reduced Np solution. 233 Pa, obtained 233 Pa diluent.

[0007] In some embodiments, an HPQ resin column is used to separate the reduced Np solution using an aqueous nitric acid solution as the eluent. 233 Pa, obtained 233 The steps for applying Pa diluent include the following sub-steps: S131: The HPQ resin is pretreated by repeatedly washing it with pure water and an aqueous HNO3 solution with a concentration of 1M to 2M. S132: The pretreated HPQ resin is packed into a separation column to obtain an HPQ resin column, and then the HPQ resin column is equilibrated with an aqueous HNO3 solution of 7M to 8M concentration. S133: Load the reduced Np solution into the equilibrated HPQ resin column and collect... 233 Pa rinsing solution; S134: Elute the HPQ resin column with an aqueous HNO3 solution of 4.5M to 5.5M concentration, and then further collect... 233Pa eluent, and the sample collected in step S133 233 The Pa eluents were combined to obtain 233 Pa diluent.

[0008] In some implementations, the measurement of 233 Step S2, which determines the concentration of Pa diluent, includes the following sub-steps: S21: Measuring the concentration of uranium in uranium standard samples of known age using isotope dilution mass spectrometry. 235 U / 233 U isotope ratios were used to obtain the uranium standard sample. 235 The number of atoms of U; S22: Based on the known age t of the uranium standard sample, the measured... 235 The number of U atoms in the uranium standard sample is calculated using the formula (2). 231 The number of atoms in Pa; S23: The third amount prepared in step S1 233 Pa diluent is added to the HNO3 aqueous solution of the uranium standard sample to obtain the uranium standard sample solution to be separated; S24: Use an AG1-X8 resin column to separate the Pa sample from the uranium standard sample solution to be separated; S25: Measure the Pa sample obtained in step S24. 233 Pa / 231 Pa isotope ratios; S26: Based on the uranium standard sample obtained in step S22... 231 The number of atoms of Pa and the measurements obtained in step 25 233 Pa / 231 Pa isotope ratios were calculated. 233 The number of atoms of Pa, and then based on that calculation... 233 The number of atoms of Pa and the third quantity are used to calculate the... 233 Pa is the concentration of the diluent.

[0009] In some embodiments, step S24, which involves separating the Pa sample from the uranium standard sample solution using an AG1-X8 resin column, includes the following sub-steps: S241: The AG1-X8 resin is pretreated by repeatedly washing it with pure water and an HNO3 aqueous solution with a concentration of 1M to 2M. S242: The pretreated AG1-X8 resin is packed into a separation column to obtain an AG1-X8 resin column, and then the AG1-X8 resin column is equilibrated with an HCl aqueous solution of 8M to 10M. S243: Load the uranium standard sample solution to be separated into an equilibrated AG1-X8 resin column; S244: Elute the AG1-X8 resin column with an HCl aqueous solution of 8M to 10M to remove impurities; S245: Elute the AG1-X8 resin column with an aqueous solution of HCl with a concentration of 8M to 10M and HF with a concentration of 0.01M to 1M to elute Pa, and obtain Pa eluent as Pa sample.

[0010] In some embodiments, in step S3, isotope dilution mass spectrometry is used to measure the concentration of uranium in the analyte. 234 Number of atoms of U N 1 ’ and 235 Number of atoms of U N 1.

[0011] In some embodiments, step S5, which uses an AG1-X8 resin column to separate the Pa and Th samples from the uranium sample to be separated, includes the following sub-steps: S51: The AG1-X8 resin is pretreated by repeatedly washing it with pure water and an HNO3 aqueous solution with a concentration of 1M to 2M. S52: The pretreated AG1-X8 resin is packed into a separation column to obtain an AG1-X8 resin column, and then the AG1-X8 resin column is equilibrated with an 8M to 10M HCl aqueous solution. S53: Load the uranium sample to be separated into a balanced AG1-X8 resin column; S54: Elute the AG1-X8 resin column with an HCl aqueous solution of 8M to 10M to obtain Th eluent, which is used as the Th sample; S55: Elute the AG1-X8 resin column with an aqueous solution of HCl with a concentration of 8M to 10M and HF with a concentration of 0.01M to 1M to elute Pa, and obtain Pa eluent as Pa sample.

[0012] In some embodiments, in step S6, inductively coupled plasma mass spectrometry (ICP-MS) is used to measure the concentration of Pa in the separated Pa sample. 233 Pa / 231 Pa isotope ratio and the Th sample obtained from the separation 229 Th / 230 Th isotope ratio.

[0013] In some embodiments, a first amount is added to the uranium material to be tested. 233 Pa diluent and second amount 229Before step S4 of the Th diluent step, there is also a step of dissolving the uranium material to be tested in an aqueous HNO3 solution with a concentration of 5M to 7M.

[0014] The embodiments of this application have at least the following beneficial effects.

[0015] 1. In some embodiments, the method of this application only requires the analysis of one uranium material, involves a relatively short experimental cycle, and can effectively separate U, Th, and Pa using an AG1-X8 resin column, ultimately obtaining comparable results simultaneously. 230 Th- 234 U and 231 Pa- 235 The U-model age value optimized the experimental procedure, shortened the experimental cycle, and reduced the amount of uranium material used.

[0016] 2. In some embodiments, the method of this application in the preparation 233 In the operation of Pa diluent, only hydrazine hydrate reducing agent is used to reduce Np in the initial Np solution under the condition of heat preservation at 70℃ to 90℃. 6+ and Np 5+ Equal high price Np to Np 4+ This eliminates the need to introduce ferrous aminosulfonate (FS), which has stronger reducing properties, avoids the introduction of other metals such as Fe, and saves the trouble of removing metal impurities.

[0017] 3. In some embodiments, the method of this application in the preparation 233 In the operation of Pa diluent, only one HPQ resin column is needed with a 4.5M to 5.5M HNO3 aqueous solution as the eluent to achieve effective separation of Np and Pa. This avoids the introduction of HF, eliminates the complex HClO4 or H3BO3 defluorination and system transfer operations, and shortens the preparation time. 233 Experimental procedure and time for Pa diluent.

[0018] 4. In some embodiments, the method of this application sets a value. 233 In the operation of Pa diluent, using only an AG1-X8 resin column and an aqueous solution of HCl with a concentration of 8M to 10M and HF with a concentration of 0.01M to 1M as the eluent, U and Pa can be effectively separated, which is beneficial for the preparation of self-made diluents. 233 Pa diluent was used to accurately determine the value. Attached Figure Description

[0019] Figure 1 It shows 230 Th- 234 U and 231 Pa- 235 A schematic diagram of the U-model for measuring the age of uranium materials.

[0020] Figure 2 A flowchart illustrating a method for simultaneously measuring the ages of two models of uranium material according to an embodiment of this application is shown.

[0021] Figure 3 and Figure 4 The set values ​​shown in the embodiment are 233 The calculation process for Pa diluent, where, Figure 4 The table in the middle is Figure 3 A continuation of the table shown in the figure.

[0022] Figure 5 and Figure 6 The embodiments are shown by 230 Th- 234 The process of calculating the age of the U850 uranium octoxide standard sample using the U-model, wherein... Figure 6 The table in the middle is Figure 5 A continuation of the table shown in the figure.

[0023] Figure 7 and Figure 8 The embodiments are shown by 231 Pa- 235 The process of calculating the age of the U850 uranium octoxide standard sample using the U-model, wherein... Figure 8 The table in the middle is Figure 7 A continuation of the table shown in the figure. Detailed Implementation

[0024] The technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the implementation methods of this application. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments in this application without inventive effort are within the scope of protection of this application.

[0025] Throughout this specification, unless otherwise specified, the terminology used herein should be understood as having the meaning commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. In the event of any conflict, this specification shall prevail.

[0026] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a product or method that comprises a list of elements includes not only the elements expressly stated, but also other elements not expressly listed, or elements inherent to implementing the product, method, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other related elements in the product or method that includes that element.

[0027] The mother-child pair model used in destructive age measurement methods for uranium materials is mainly... 231 Pa- 235 U and 230 Th- 234 U. like Figure 1 As shown, according to the fundamental radioactive decay laws of U isotopes, to obtain the age of uranium materials, in 230 Th- 234 In the U-model, isotope dilution mass spectrometry is required to measure the values ​​separately. 230 Th and 234 The quantity of U, of which 230 Th use 229 Th diluent set value, 234 U use 233 U diluent set value. 231 Pa- 235 In the U-model, isotope dilution mass spectrometry is required to measure the values ​​separately. 231 Pa and 235 The quantity of U, of which 235 The amount of U can be used 233 U was measured with diluent, while the measurement 231 Pa is used 233 Pa diluent needs to be obtained from 237 Extracted, purified, and analyzed from Np cows. The results were obtained using CRM U100 standard samples. 231 Pa value for the prepared 233 The process for determining the Pa diluent value is as follows: 233 U is the diluent used to measure U100. 235 The accurate quantity of U, according to 235 The U decay chain can be calculated from the actual age of U100. 231 The amount of Pa was measured by ICP-MS. 233 Pa / 231 The Pa ratio is used to obtain the prepared product. 233 The value of Pa diluent.

[0028] To more fully determine the production date of uranium materials and obtain information about their production processes, it is necessary to obtain the ages from two models in the material provenance analysis. Published literature either only uses... 231 Pa- 235 U-model, or only use 230 Th- 234 The U-model is used to measure the age of uranium materials. Obtaining ages from two different models requires two separate experiments and destructive analysis of two uranium samples. In material provenance analysis, minimizing uranium consumption is crucial. Furthermore, the future development trend of uranium age detection technology is towards gradually increasing detection capabilities and decreasing sample quantities.

[0029] Therefore, there is a need for a method for measuring the age of uranium materials that can simultaneously perform... 230 Th- 234 U and 231 Pa- 235 Measuring the age using both models can reduce the amount of uranium material used, shorten the experimental process and time, and the ages obtained from the two models are comparable, which can be used to evaluate the accuracy of the measured age.

[0030] In view of this, this application provides a method for simultaneously measuring the ages of two models of uranium material. The method includes: S1: Preparation 233 Pa diluent; S2: Measure the 233 Pa diluent concentration; S3: Measuring the uranium material to be tested 234 Number of atoms of U N 1 ’ and 235 Number of atoms of U N 1; S4: Add the first amount of uranium material to be tested. 233 Pa diluent and second amount 229 Th diluent, to obtain the uranium sample to be separated, wherein... 229 The concentration of the diluent is known; S5: Use an AG1-X8 resin column to separate the Pa and Th samples from the uranium sample to be separated; S6: Measure the Pa content in the separated Pa sample. 233 Pa / 231 Pa isotope ratio and the Th sample obtained from the separation 229 Th / 230 Th isotope ratios; S7: Based on the measurements obtained in step S2 233The concentration of Pa diluent, added in step S4 233 The first amount of Pa diluent and the amount measured in step S6 233 Pa / 231 Pa isotope ratios were calculated to obtain the content of the uranium material to be tested. 231 number of atoms of Pa N 3; S8: Based on known... 229 The concentration of the diluent, added in step S4 229 The second amount of Th diluent and the amount measured in step S6 229 Th / 230 The Th isotope ratio was used to calculate the content of th in the uranium material being tested. 230 Number of Th atoms N 2 ’ ; S9: Calculate according to formula (1) 230 Th- 234 The age of the uranium material to be tested obtained from the U-model; Formula (1), In formula (1), t' indicates by 230 Th- 234 Age of uranium material obtained by the U model λ1' represents 234 The decay constant of U, λ2' represents 230 The decay constant of Th, N2' indicates that uranium material contains 230 The number of atoms of Th N1' indicates that uranium material contains 234 The number of atoms of U N2' / N1' indicates the uranium material in 230 Th / 234 U atom ratio; S10: Calculate according to formula (2) 231 Pa- 235 The age of the uranium material to be tested obtained from the U-model; Formula (2), In formula (2), t represents by 231 Pa- 235 Age of uranium material obtained by the U model λ1 represents 235 The decay constant of U, λ3 represents 231 decay constant of Pa N3 indicates that uranium material contains231 The number of atoms in Pa. N1 indicates that uranium material contains 235 The number of atoms of U N3 / N1 indicates that in uranium materials... 231 Pa / 235 U atom number ratio.

[0031] In the method of this application, Th and Pa can be separated from uranium material using only one AG1-X8 resin separation column, while uranium is continuously adsorbed on the resin, thereby separating U, Th, and Pa from each other. Then, the Pa content in the separated sample is measured. 233 Pa / 231 Pa isotope ratio and the Th sample obtained from the separation 229 Th / 230 Th isotope ratios, combined with those added to uranium materials 233 The specific dosage of Pa diluent and 229 The specific amount of Th diluent used can reveal the concentration of uranium in the material. 231 Pa and 230 The number of Th atoms. Based on uranium materials 231 Pa and 230 The number of Th atoms and the amount of uranium material measured in step S3 234 Number of atoms of U N 1 ’ and 235 Number of atoms of U N 1. The ages of the two uranium material models can be calculated using formulas (1) and (2) respectively. In related technologies, two uranium materials are required, one for measurement... 230 Th- 234 U-model age, another one used for measurement 231 Pa- 235 U-model age. In the method of this application, only one uranium material needs to be analyzed; U, Th, and Pa can be effectively separated using AG1-X8 resin, ultimately yielding comparable values ​​simultaneously. 230 Th- 234 U and 231 Pa- 235 The U-model age value optimized the experimental procedure, shortened the experimental cycle, and reduced the amount of uranium material used.

[0032] In some implementations, preparation 233 Step S1 for Pa diluent includes the following sub-steps: S11: Provides the initial Np solution; S12: Using hydrazine hydrate as a reducing agent, the Np in the initial Np solution is reduced under a temperature holding condition of 70°C to 90°C.6+ and Np 5+ Equal valence state Np is reduced to Np 4+ The valence state of Np is adjusted to Np. 4+ Reduced Np solution; S13: Separate from the reduced Np solution 233 Pa, obtained 233 Pa diluent.

[0033] Because Np is an element with variable valence, it can exist in Np solution in multiple valence states, such as +6, +5, and +4. In order to separate Np from Np solution... 233 Pa needs to have its Np value adjusted to Np as much as possible. 4+ In step S12 above, Np can be removed by using only hydrazine hydrate reducing agent under a temperature holding condition of 70°C to 90°C. 6+ and Np 5+ Equal valence state Np is reduced to Np 4+ This eliminates the need to introduce ferrous aminosulfonate (FS), which has stronger reducing properties, thus avoiding the introduction of other metals (such as Fe) and eliminating the need for metal impurity removal. For example, the temperature of the above-mentioned insulation conditions can be 70°C, 75°C, 80°C, 85°C, or 90°C. Optionally, the temperature of the above-mentioned insulation conditions can be 80°C.

[0034] In some embodiments, in step S13, an HPQ resin column is used with an aqueous nitric acid solution as the eluent to separate the Np from the reduced Np solution. 233 Pa, obtained 233 Pa diluent. Np solution contains hundreds of picograms. 233 Pa. In the Np solution, Np... 6+ and Np 5+ Equal valence state Np is reduced to Np 4+ Subsequently, an HPQ resin column can be used to separate Np and Pa using an aqueous nitric acid solution as the eluent. In a high-concentration nitric acid system, Np... 4+ It can form anionic nitrate complexes (Np(NO3)6) 2- The Pa is adsorbed onto the HPQ resin, while Pa is directly leached off, thus... 233Pa is separated from the Np solution, achieving effective separation of Np and Pa. In related techniques, multiple separations using different resin columns are typically required to purify Pa, and these processes often involve complex HClO4 or H3BO3 defluorination and system transfer operations, resulting in lengthy experimental procedures and time-consuming evaporation and reconstitution. In the separation process described in this application, HF is not introduced, thus eliminating the need for complex HClO4 or H3BO3 defluorination and system transfer operations, thereby shortening the experimental process and time. Furthermore, the tailing effect is relatively small when eluting and recovering Np using HPQ resin.

[0035] In some embodiments, in step S13, an aqueous solution of HNO3 with a concentration of 4.5M to 5.5M is used as the eluent to... 233 Pa is eluted from the HPQ resin column, thereby separating it from the reduced Np solution. 233 Pa. For example, rinsing. 233 The concentration of the HNO3 aqueous solution at Pa can be 4.5M, 5M, or 5.5M. Optionally, rinsing... 233 The concentration of the HNO3 aqueous solution at Pa can be 5M. Using an aqueous nitric acid solution within the above concentration range is beneficial for... 233 Pa is eluted from the HPQ resin column without the need to introduce HF, eliminating the need for defluorination and avoiding the need for multiple different resin columns in series, thus eliminating the complicated system transfer operation.

[0036] In some embodiments, an HPQ resin column is used to separate the reduced Np solution using an aqueous nitric acid solution as the eluent. 233 Pa, obtained 233 The steps for applying Pa diluent include the following sub-steps: S131: The HPQ resin is pretreated by repeatedly washing it with pure water and an aqueous HNO3 solution with a concentration of 1M to 2M. S132: The pretreated HPQ resin is packed into a separation column to obtain an HPQ resin column, and then the HPQ resin column is equilibrated with an aqueous HNO3 solution of 7M to 8M concentration. S133: Load the reduced Np solution into the equilibrated HPQ resin column and collect... 233 Pa rinsing solution; S134: Elute the HPQ resin column with an aqueous HNO3 solution of 4.5M to 5.5M concentration, and then further collect... 233 Pa eluent, and the sample collected in step S133 233 The Pa eluents were combined to obtain 233 Pa diluent.

[0037] The Np solution contains hundreds of picograms. 233Pa. In the Np solution, Np... 6+ and Np 5+ Equal valence state Np is reduced to Np 4+ Subsequently, an HPQ resin column can be used with a 4.5M to 5.5M HNO3 aqueous solution as the eluent to... 233 Pa is separated from the Np solution, achieving effective separation of Np and Pa. The inventors used a low-background gamma spectrometer to monitor the elution of Pa under different elution conditions and found that aqueous solutions of HNO3 with concentrations ranging from 4.5M to 5.5M could effectively elute Pa, while Np was adsorbed onto the HPQ resin column. In the above separation process, HF is not required, which correspondingly eliminates the complex HClO4 or H3BO3 defluorination and system transfer operations, thereby shortening the experimental procedure and time.

[0038] In some embodiments, an HPQ resin column is used to separate the reduced Np solution using an aqueous nitric acid solution as the eluent. 233 Pa, obtained 233 The Pa diluent step may further include sub-step S135: after sub-step S134, the HPQ resin column is eluted with an aqueous HNO3 solution of 0.1M to 0.6M concentration to elute and recover the Np solution. The recovered Np solution can be used for subsequent production. 233 Pa. For example, the concentration of the HNO3 aqueous solution used for eluting and recovering Np can be 0.1M, 0.2M, 0.3M, 0.4M, 0.5M, or 0.6M. Optionally, the concentration of the HNO3 aqueous solution used for eluting and recovering Np can be 0.3M. Using an aqueous nitric acid solution within the above concentration range is beneficial for eluting Np from the HPQ resin column, resulting in a smaller tailing effect during Np elution and recovery.

[0039] In some implementations, the measurement of 233 Step S2, which determines the concentration of Pa diluent, includes the following sub-steps: S21: Measuring the concentration of uranium in uranium standard samples of known age using isotope dilution mass spectrometry. 235 U / 233 U isotope ratios were used to obtain the uranium standard sample. 235 The number of atoms of U; S22: Based on the known age t of the uranium standard sample, the measured... 235 The number of U atoms in the uranium standard sample is calculated using the formula (2). 231 The number of atoms in Pa; S23: The third amount prepared in step S1 233 Pa diluent is added to the HNO3 solution of the uranium standard sample to obtain the uranium standard sample solution to be separated; S24: Use an AG1-X8 resin column to separate the Pa sample from the uranium standard sample solution to be separated; S25: Measure the Pa sample obtained in step S24. 233 Pa / 231 Pa isotope ratios; S26: Based on the uranium standard sample obtained in step S22... 231 The number of atoms of Pa and the measurements obtained in step 25 233 Pa / 231 Pa isotope ratios were calculated. 233 The number of atoms of Pa, and then based on that calculation... 233 The number of atoms of Pa and the third quantity are used to calculate the... 233 Pa is the concentration of the diluent.

[0040] In step S24 above, Pa can be separated from uranium material using only one AG1-X8 resin separation column, while uranium remains adsorbed on the resin, thus achieving effective separation of U and Pa to obtain a Pa sample. Then, the concentration of U in the separated Pa sample is measured. 233 Pa / 231 Pa isotope ratios obtained based on this measurement. 233 Pa / 231 The Pa isotope ratio and the uranium standard sample obtained in step S22 231 The number of Pa atoms can be calculated. 233 The number of atoms of Pa. Furthermore, based on this calculation... 233 The number of atoms of Pa and the amount added 233 The third amount of Pa diluent can be calculated. 233 The concentration of Pa diluent. This achieves the desired concentration. 233 Accurate value of Pa diluent.

[0041] In some embodiments, the uranium standard sample in step S21 is selected from U100 uranium trioxide standard sample or U850 uranium trioxide standard sample. Optionally, the uranium standard sample in step S21 is selected from U100 uranium trioxide standard sample. Using the above standard samples is beneficial for... 233 Pa diluent was used to accurately determine the value.

[0042] In some embodiments, in step S25, ICP-MS is used to measure the Pa content in the Pa sample separated in step S24. 233 Pa / 231 Pa isotope ratio.

[0043] In some embodiments, in step S24, an aqueous solution of HCl with a concentration of 8M to 10M and HF with a concentration of 0.01M to 1M is used as the eluent to elute Pa from the AG1-X8 resin column, thereby separating the Pa sample from the uranium standard sample solution to be separated. The description "an aqueous solution of HCl with a concentration of 8M to 10M and HF with a concentration of 0.01M to 1M" refers to a mixed aqueous solution of hydrochloric acid and hydrofluoric acid, wherein the concentration of hydrochloric acid can be 8M to 10M and the concentration of hydrofluoric acid can be 0.01M to 1M. Exemplarily, the concentration of hydrochloric acid can be 8M, 8.5M, 9M, 9.5M, or 10M; optionally, the concentration of hydrochloric acid can be 9M. For example, the concentration of hydrofluoric acid can be 0.01M, 0.02M, 0.03M, 0.04M, 0.05M, 0.06M, 0.07M, 0.08M, 0.09M, 0.1M, 0.3M, 0.5M, 0.8M, or 1M. Optionally, the concentration of hydrofluoric acid can be 0.05M. Using the above-mentioned mixed aqueous solution of hydrochloric acid and hydrofluoric acid is beneficial for eluting Pa from the AG1-X8 resin column, achieving the separation of Pa and U, thereby facilitating subsequent processing. 233 Pa diluent was used to accurately determine the value.

[0044] In some embodiments, step S24, which involves separating the Pa sample from the uranium standard sample solution using an AG1-X8 resin column, includes the following sub-steps: S241: The AG1-X8 resin is pretreated by repeatedly washing it with pure water and an HNO3 aqueous solution with a concentration of 1M to 2M. S242: The pretreated AG1-X8 resin is packed into a separation column to obtain an AG1-X8 resin column, and then the AG1-X8 resin column is equilibrated with an HCl aqueous solution of 8M to 10M. S243: Load the uranium standard sample solution to be separated into an equilibrated AG1-X8 resin column; S244: Elute the AG1-X8 resin column with an HCl aqueous solution of 8M to 10M to remove impurities; S245: Elute the AG1-X8 resin column with an aqueous solution of HCl with a concentration of 8M to 10M and HF with a concentration of 0.01M to 1M to elute Pa. The resulting Pa eluent is used as the Pa sample.

[0045] In this embodiment, only one AG1-X8 resin separation column is used, with an aqueous solution of HCl (8M to 10M) and HF (0.01M to 1M) as the eluent. Pa can be separated from uranium materials while uranium remains adsorbed on the resin, thus achieving effective separation of U and Pa to obtain a Pa sample. This facilitates subsequent analysis... 233 Accurate value of Pa diluent.

[0046] In some embodiments, in step S3, isotope dilution mass spectrometry is used to measure the concentration of uranium in the analyte. 234 Number of atoms of U N 1 ’ and 235 Number of atoms of U N 1. Isotope dilution mass spectrometry is a metrological method that achieves accurate quantification of trace elements by adding isotope diluents combined with mass spectrometry analysis. As an example, in this application, the following procedure can be used to measure the amount of trace elements in the uranium material to be tested. 234 Number of atoms of U N 1 ’ and 235 Number of atoms of U N 1: Add a predetermined amount of a known concentration of [unspecified substance] to the uranium material sample to be tested. 233 U diluent, so that the uranium material sample to be tested contains 235 U and 233 U、 234 U and 233 The U content was on the order of magnitude; isotope exchange was balanced under heating conditions; then, the concentration of U in the uranium material sample was measured by ICP-MS. 235 U / 233 U and 234 U / 233 U isotope ratios. 233 The amount and concentration of U diluent added and the measured values 235 U / 233 U and 234 U / 233 The U isotope ratio can be used to calculate the concentration of uranium in the uranium material sample being tested. 234 Number of atoms of U N 1 ’ and 235 Number of atoms of U N 1. As an example, the heating temperature described above can be between 70°C and 120°C, for example, 70°C, 80°C, 90°C, 100°C, 110°C, or 120°C. Optionally, the heating temperature described above can be 80°C. Heating at the above temperatures is beneficial for isotope exchange equilibrium, achieving... 235 U / 233 U and 234 U / 233 Accurate measurement of U isotope ratios.

[0047] In some embodiments, in step S5, an aqueous HCl solution with a concentration of 8M to 10M is used as the rinsing solution for Th. For example, in step S5, the concentration of HCl in the aqueous HCl solution can be 8M, 8.5M, 9M, 9.5M, or 10M, and optionally, it can be 9M.

[0048] In some embodiments, in step S5, an aqueous solution of HCl with a concentration of 8M to 10M and HF with a concentration of 0.01M to 1M is used as the rinsing solution for rinsing Pa. The description of "an aqueous solution of HCl with a concentration of 8M to 10M and HF with a concentration of 0.01M to 1M" is as described above and will not be repeated here.

[0049] In this embodiment, only one AG1-X8 resin separation column is used. An aqueous HCl solution with a concentration of 8M to 10M is used as the eluent for Th, and an aqueous solution of HCl with a concentration of 8M to 10M and HF with a concentration of 0.01M to 1M is used as the eluent for Pa. U is continuously adsorbed on the AG1-X8 resin, thereby achieving the separation of U / Th / Pa. No additional resin column separation is required. This enables the simultaneous measurement of the ages of uranium materials using two models, and the ages obtained from the two models are comparable.

[0050] In some embodiments, step S5, which uses an AG1-X8 resin column to separate the Pa and Th samples from the uranium sample to be separated, includes the following sub-steps: S51: The AG1-X8 resin is pretreated by repeatedly washing it with pure water and an HNO3 aqueous solution with a concentration of 1M to 2M. S52: The pretreated AG1-X8 resin is packed into a separation column to obtain an AG1-X8 resin column, and then the AG1-X8 resin column is equilibrated with an 8M to 10M HCl aqueous solution. S53: Load the uranium sample to be separated into a balanced AG1-X8 resin column; S54: Elute the AG1-X8 resin column with an HCl aqueous solution of 8M to 10M to obtain Th eluent, which is used as the Th sample; S55: Elute the AG1-X8 resin column with an aqueous solution of HCl with a concentration of 8M to 10M and HF with a concentration of 0.01M to 1M to elute Pa, and obtain Pa eluent as Pa sample.

[0051] In this embodiment, only one AG1-X8 resin separation column is used. An aqueous HCl solution with a concentration of 8M to 10M is used as the eluent for Th, and an aqueous HCl solution with a concentration of 8M to 10M and an HF solution with a concentration of 0.01M to 1M is used as the eluent for Pa. U is continuously adsorbed on the AG1-X8 resin, thereby achieving effective separation among U, Th, and Pa. No additional resin column separation is required. This enables the simultaneous measurement of the ages of uranium materials using two models, and the ages obtained from the two models are comparable.

[0052] In some embodiments, in step S6, ICP-MS is used to measure the concentration of Pa in the separated Pa sample. 233 Pa / 231 Pa isotope ratio and the Th sample obtained from the separation 229 Th / 230 Th isotope ratio.

[0053] In some embodiments, a first amount is added to the uranium material to be tested. 233 Pa diluent and second amount 229 Before step S4 of the Th diluent step, a step of dissolving the uranium material to be tested in an aqueous HNO3 solution with a concentration of 5M to 7M is included. A uranium material mother liquor is prepared by dissolving the uranium material to be tested in the HNO3 aqueous solution. The uranium material mother liquor can then be diluted with pure water to obtain a diluted mother liquor. Then, by adding [unclear text - likely a continuation of the previous sentence] to the diluted mother liquor... 233 U diluent, measured 235 U / 233 U and / or 234 U / 233 U isotope ratio, determined by adding to the diluted mother liquor 233 Pa diluent and 229 The diluent was detected. 233 Pa / 231 Pa isotope ratio and / or 229 Th / 230 Th isotope ratio.

[0054] In the method of this application, when using 230 Th- 234 The formula for calculating the age of uranium materials using the U-model is as follows: Formula (1), In formula (1), λ1' represents 234 The decay constant of U; λ2' represents 230 The decay constant of Th; N2' / N1' represents the decay constant of uranium material. 230 Th / 234U atomic ratio; t' indicates the ratio of U atoms; 230 Th- 234 Ages of uranium materials obtained using the U-model.

[0055] In the method of this application, when using 231 Pa- 235 The formula for calculating the age of uranium materials using the U-model is as follows: Formula (2), In formula (2), λ1 represents 235 The decay constant of U; λ3 represents 231 The decay constant of Pa; N3 / N1 represents the decay constant of uranium material. 231 Pa / 235 U atomic number ratio; t represents the ratio of U atoms; 231 Pa- 235 Ages of uranium materials obtained using the U-model.

[0056] In the above text, 234 The decay constant of U, 235 The decay constant of U, 230 The decay constant of Th and 231 The decay constant of Pa was obtained from data in the Brookhaven National Laboratory database.

[0057] In some implementations, preparation 233 Pa diluent (step S1) and measurement of the 233 The concentration of Pa diluent (step S2) is as follows.

[0058] The Np solution (containing hundreds of picograms) 233 After evaporating the Np solution to near dryness, the system is converted to 7.5M HNO3. Sufficient hydrazine hydrate is added, and the solution is heated at high temperature to fully reduce hexavalent and pentavalent Np to tetravalent Np. In one embodiment, approximately 20 mg of Np solution is taken, evaporated to near dryness, and the system is converted to 7.5M HNO3. Hydrazine hydrate is added at a molar ratio of 1:3 (Np to hydrazine hydrate), and the solution is heated at 80°C to fully reduce hexavalent and pentavalent Np to tetravalent Np.

[0059] HPQ resin was wet-packed into a separation column, then washed and equilibrated with 7.5 M HNO3. A tetravalent Np solution was loaded into the column, and Pa solution was eluted with 5 M HNO3. [The following is a separate, unrelated sentence:] The solution was collected... 233 The Pa eluent was finally eluted with 0.3M HNO3 to recover the Np solution for continued production. 233Pa. The Pa eluent is concentrated by heating on a hot plate for later use. In one embodiment, after washing the HPQ resin multiple times with pure water and an aqueous HNO3 solution of 1M to 2M concentration, the washed HPQ resin is immersed in an aqueous 1M HNO3 solution for later use. Approximately 8 mL of HPQ resin is wet-packed into a separation column with an inner diameter of 8 mm, and then 16 mL of 7.5M HNO3 is added to wash and equilibrate the resin column. The tetravalent Np solution is loaded into the column, and the Pa eluent is collected in a PFA flask. The Pa solution is then further eluted with 48 mL of 5M HNO3 aqueous solution, and finally eluted with 24 mL of 0.3M HNO3 to recover the Np solution for further production. 233 Pa. In one embodiment, the Pa eluent is concentrated to approximately 10 mL by heating on a hot plate at 80°C for later use. 233 Pa diluent.

[0060] Add 6M HNO3 aqueous solution to an accurately weighed U100 uranium octoxide standard sample, heat until completely dissolved, to obtain U100 mother liquor. Accurately weigh a portion of the U100 mother liquor, dilute it stepwise with pure water to the appropriate concentration, and then accurately weigh a certain amount... 233 U diluent is added to the dilution stock solution to make the sample... 233 U and 235 The U content was on the order of magnitude. After heating to achieve isotopic exchange equilibrium, measurements were performed using ICP-MS. 235 U / 233 U isotope ratios. In one embodiment, approximately 0.01 g of U100 uranium octoxide standard sample is accurately weighed, 5 mL of 6M HNO3 aqueous solution is added, and the sample is placed on a 110°C electric heating plate to dissolve completely, yielding a U100 mother liquor. In another embodiment, the sample is heated on an 80°C electric heating plate to achieve isotope exchange equilibrium, and then measured using ICP-MS. 235 U / 233 U isotope ratio.

[0061] Accurately weigh one portion of U100 stock solution and add a certain amount of homemade [product name missing]. 233 Pa diluent makes the sample contain 233 Pa and 231 The Pa content is on the order of magnitude. After heating to achieve isotope exchange equilibrium, the system is converted to a 9M HCl system for separation. In one embodiment, heating is performed on an 80°C hot plate to achieve isotope exchange equilibrium, and then the system is converted to a 9M HCl system for separation.

[0062] AG1-X8 resin was wet-packed into a separation column, and then the column was equilibrated with 9M HCl. After loading the sample into the column, impurities were eluted with 9M HCl, and finally Pa was eluted with a 9M HCl-0.05M HF aqueous solution to obtain the Pa eluent. The Pa eluent was then converted to a 2% HNO3 system and measured using ICP-MS. 233 Pa / 231 Pa isotope ratio. In one embodiment, after repeatedly washing the AG1-X8 resin with pure water and an aqueous solution of HNO3 with a concentration of 1M to 2M, the washed AG1-X8 resin is soaked in 1M HCl solution for later use. Approximately 6 mL of AG1-X8 resin is wet-packed into a separation column with an inner diameter of 8 mm, and then 12 mL of 9M HCl is added to equilibrate the resin column. After loading the sample into the column, impurities are eluted with 30 mL of 9M HCl, and finally Pa is eluted with 30 mL of 9M HCl-0.05M HF to obtain the Pa eluent. The Pa eluent is evaporated to near dryness and then reconstituted with 1 mL of concentrated HNO3, evaporated to near dryness again, and then reconstituted with 2 mL of 2% HNO3. The value is measured using ICP-MS. 233 Pa / 231 Pa isotope ratio.

[0063] Finally, according to 233 The amount of Pa diluent added, the purification date of U100 (January 8, 1959), and the measured values... 233 Pa / 231 Pa and 235 U / 233 The U isotope ratio was calculated using formula (2) to obtain the self-made [product / product]. 233 Pa is the concentration of the diluent.

[0064] In some implementations, the uranium material to be tested is measured. 234 Number of atoms of U N 1 ’ and 235 Number of atoms of U N 1 (Step S3) is as follows.

[0065] Accurately weigh 230 Th and 231 Uranium material with a Pa content meeting the requirements for ICP-MS measurement is added to a 6M HNO3 aqueous solution and heated until completely dissolved to obtain a uranium material mother liquor. In one embodiment, accurately weigh... 230 Th and 231 Uranium material with a Pa content that meets the requirements for ICP-MS measurement was added to 5 mL of 6M HNO3 aqueous solution and placed on an electric heating plate at 110℃ to dissolve completely, thus obtaining the uranium material mother liquor.

[0066] Accurately weigh one portion of uranium material mother liquor, dilute it stepwise with pure water to the appropriate ratio, and then accurately weigh a certain amount... 233 U diluent is added to the dilution stock solution to make the sample... 235 U and 233 U、 234 U and 233 The U content was on the same order of magnitude. After heating to achieve isotopic exchange equilibrium, it was measured using ICP-MS. 235 U / 233 U、 234 U / 233 U isotope ratio. In one embodiment, after heating on a hot plate at 80°C to achieve isotope exchange equilibrium, the ratio is measured using ICP-MS. 235 U / 233 U、 234 U / 233 U isotope ratios. Based on measurements. 235 U / 233 U、 234 U / 233 U isotope ratios and known quantities 233 U can be calculated 234 Number of atoms of U N 1 ’ and 235 Number of atoms of U N 1.

[0067] In some embodiments, a first amount of uranium material to be tested is added. 233 Pa diluent and second amount 229 Th diluent is used to obtain the uranium sample to be separated (step S4). The Pa and Th samples are separated from the uranium sample using an AG1-X8 resin column (step S5), and the concentrations in the separated Pa sample are measured. 233 Pa / 231 Pa isotope ratio and the Th sample obtained from the separation 229 Th / 230 The Th isotope ratio (step S6) is described below.

[0068] Accurately weigh one portion of the mother liquor of the uranium material to be tested, and accurately weigh a certain amount of... 233 Pa diluent and 229 Th diluent is added to the mother liquor of the uranium material to be tested to make the sample... 233 Pa and 231 Pa、 229 Th and 230The Th content is on the same order of magnitude. After heating to achieve isotopic exchange equilibrium, the system is converted to 9M HCl for separation. In one embodiment, the isotopic exchange equilibrium is achieved by heating on a hot plate at 80°C, and then the system is converted to 9M HCl for separation.

[0069] AG1-X8 resin was wet-packed into a separation column, and then the column was equilibrated with 9M HCl. After loading the sample into the column, Th was eluted with 9M HCl to obtain the Th eluent. Finally, Pa was eluted with 9M HCl-0.05M HF to obtain the Pa eluent. Both the Th eluent and the Pa eluent were then converted to a 2% HNO3 system, and the concentrations of Th and Pa in the two samples were measured using ICP-MS. 229 Th / 230 Th and 233 Pa / 231 Pa isotope ratio. In one embodiment, approximately 6 mL of AG1-X8 resin is wet-packed into an 8 mm inner diameter separation column, followed by the addition of 12 mL of 9 M HCl to equilibrate the column. The sample is then loaded into the column, and the Th eluent is collected using a PFA bottle. Th is then further eluted with 30 mL of 9 M HCl, and the Th eluent is collected. Finally, Pa is eluted with 30 mL of 9 M HCl-0.05 M HF, and the Pa eluent is collected. The Th and Pa eluents are evaporated to near dryness and then reconstituted with 1 mL of concentrated HNO3, followed by evaporation to near dryness and reconstitution with 2 mL of 2% HNO3. ICP-MS is then used to measure the Pa isotope ratio in both samples. 229 Th / 230 Th and 233 Pa / 231 Pa isotope ratio.

[0070] Finally, according to Figure 2 Steps S7 to S10 shown in the figure can be used to calculate the two model ages of uranium materials.

[0071] because 233 Pa has a relatively short half-life, so it is preferable to minimize the experimental period. In some implementations, the measurement time can be integrated by performing the measurement in a Class B laboratory. 233 After the Pa diluent is prepared, the weighing, dissolution, dilution, addition of diluent, isotope exchange equilibrium, separation by AG1-X8 resin column can be completed simultaneously with the U100 uranium octoxide standard sample and the uranium material to be tested. Finally, the isotope ratios of all samples are measured by ICP-MS.

[0072] The present application will be described in further detail below with reference to specific embodiments. The purpose of this description is merely illustrative and not intended to limit the scope of this disclosure.

[0073] In the following embodiments, unless otherwise specified, all components used are commercially available products. Furthermore, all equipment and instruments involved are commercially available standardized products, and their operating conditions and parameter settings are in accordance with the standard instructions provided by the equipment manufacturer.

[0074] Example U850 uranium octoxide standard sample was selected as the uranium material sample to be tested, to verify the simultaneous measurement in this application. 230 Th- 234 U and 231 Pa- 235 The reliability of the U-model aging method is determined by following these steps.

[0075] 1. Preparation of Np 4+ solution Weigh out an Np solution (prepared in the applicant's laboratory) containing approximately 20 mg Np, where the equilibrium anion is nitrate ion. Evaporate the weighed Np solution to near dryness and then transfer the solution to 7.5 M HNO3. Add 0.08 mL of 17 M hydrazine hydrate and incubate at 80 °C to allow the Np solution to settle. 6+ and Np 5+ Equal high price Np to Np 4+ , obtain Np 4+ Solution.

[0076] 2. Prepare HPQ resin columns After repeatedly washing the HPQ resin with pure water and a 1.5M HNO3 aqueous solution, the washed HPQ resin was then immersed in a 1M HNO3 aqueous solution for later use.

[0077] Approximately 8 mL of the HPQ resin treated as described above was packed into a separation column with an inner diameter of 8 mm using a wet packing method. Then, 16 mL of 7.5 M HNO3 aqueous solution was added to wash and equilibrate the resin column.

[0078] 3. Using HPQ resin columns from Np 4+ Separation from solution 233 Pa The Np prepared in step 1 4+ The solution was loaded into an equilibrated HPQ resin column and collected in a PFA bottle. 233 The eluent was then used to elute the HPQ resin column with 48 mL of 5 M HNO3 aqueous solution for further collection. 233 The Pa eluent was finally eluted with 24 mL of 0.3 M HNO3 aqueous solution to recover Np solution for continued production. 233 Pa. The collected 233 The Pa eluents were combined and concentrated to approximately 10 mL by heating on a hot plate at 80°C. 233Pa diluent, for later use.

[0079] 4. Measurement of U100 uranium octoxide standard sample 235 The number of U atoms and the U850 uranium octoxide standard sample 235 U and 234 Number of atoms of U Weigh approximately 10 mg of U100 uranium octoxide standard sample, add 5 mL of 6M HNO3 aqueous solution, and place on a 110℃ electric heating plate to dissolve completely, obtaining U100 mother liquor. Accurately weigh approximately 0.1 g of U100 mother liquor, dilute it stepwise with pure water 10000 times, and weigh approximately 1 g of 113.614 ng / g. 233 Add U diluent to 1g of diluted U100 stock solution to make the sample... 233 U and 235 The U content was on the order of magnitude. After isotopic exchange equilibrium was achieved by heating on an 80°C hot plate, its content was measured using ICP-MS. 235 U / 233 U isotope ratio. Due to 233 The amount of U diluent is known, so it is determined by measurement. 235 U / 233 The U isotope ratio can be used to determine the content of U100 uranium octoxide in the standard sample. 235 The number of atoms of U.

[0080] Weigh approximately 1 mg of U850 uranium octoxide standard sample, add 5 mL of 6M HNO3 solution, and place on a 110℃ electric heating plate to dissolve completely, obtaining U850 mother liquor. Weigh approximately 0.2 g of U850 mother liquor, dilute it 2000 times stepwise with pure water, and weigh approximately 1 g of 113.614 ng / g... 233 Add U diluent to 1g of diluted U850 stock solution to make the sample... 235 U and 233 U、 234 U and 233 The U content was on the order of magnitude. After heating to equilibrate the isotope exchange on an 80°C hot plate, its content was measured using ICP-MS. 235 U / 233 U、 234 U / 233 U isotope ratio. Due to 233 The amount of U diluent is known, so it is determined by measurement. 235 U / 233 U、 234 U / 233 The U isotope ratio can be used to determine the content of U850 uranium octoxide in the standard sample. 235 U and 234 The number of atoms of U.

[0081] 5. Add to the U100 uranium octoxide standard sample 233 Pa diluent and added to the U850 uranium oxide standard sample 233 Pa diluent and 229 Th diluent Weigh out approximately 0.1g of U100 stock solution and add about half of the homemade solution. 233 Pa diluent makes the sample contain 233 Pa and 231 The Pa content is on the order of magnitude. Then, after heating on an 80°C hot plate to achieve isotope exchange equilibrium, it is converted to a 9M HCl system, yielding the added... 233 The U100 mother liquor of Pa diluent is ready for separation.

[0082] Weigh out about 1g of U850 stock solution and add it to the remaining half of the homemade solution. 233 Pa diluent and 0.2g 317ng / g 229 The diluent (prepared in the applicant's laboratory) resulted in the sample containing... 233 Pa and 231 Pa、 229 Th and 230 The Th content was on the same order of magnitude. Then, after heating on an 80°C hot plate to achieve isotopic exchange equilibrium, the mixture was converted to a 9M HCl system, yielding the product with added... 233 Pa diluent and 229 The U850 mother liquor of Th diluent is ready for separation.

[0083] 6. Using an AG1-X8 resin column, separate the Pa sample from the U100 mother liquor and separate the Pa and Th samples from the U850 mother liquor. Approximately 6 mL of AG1-X8 resin was packed into an 8 mm inner diameter separation column using a wet packing method to prepare two AG1-X8 resin columns. Then, 12 mL of 9 M HCl was added to equilibrate the AG1-X8 resin columns.

[0084] Will join 233 Pa diluent U100 stock solution and added 233 Pa diluent and 229 The U850 mother liquor of Th diluent was loaded into two AG1-X8 resin columns, and the separation time was recorded as May 8, 2025, as the age calculation point.

[0085] Pa was eluted from the U100 mother liquor using 30 mL of 9M HCl-0.05M HF to obtain the Pa eluent separated from the U100 mother liquor. The Pa eluent separated from the U100 mother liquor was evaporated to near dryness, then reconstituted with 1 mL of concentrated HNO3, evaporated to near dryness again, and reconstituted with 2 mL of 2% HNO3. The Pa concentration in the sample was then measured using ICP-MS. 233 Pa / 231 Pa isotope ratio. Based on the known age t of U100 (purification date January 8, 1959) and the measurements obtained above. 235 The number of atoms of U (equivalent to the number in formula (2)) N 1) According to formula (2), the value in formula (2) can be calculated. N 3, that is 231 The number of atoms of Pa. Then, based on this... 231 The number of Pa atoms and the measured U100 233 Pa / 231 Pa isotope ratios can be calculated. 233 The amount of Pa can be used to determine the preparation method. 233 Pa diluent was used to set a value. Figure 3 and Figure 4 The value is shown in the figure. 233 The process of Pa diluent, i.e., calculation 233 The process of determining the concentration of Pa diluent. For the U850 mother liquor, collect the Th eluent using a PFA bottle, and then continue eluting the Th solution with 30 mL of 9M HCl. For the U100 sample, it is not necessary to collect the Th eluent. Finally, elute Pa with 30 mL of 9M HCl-0.05M HF to obtain the Pa eluent. Thus, the Th eluent and Pa eluent separated from the U850 mother liquor are obtained.

[0086] The Pa eluent and Th eluent from U850 were evaporated to near dryness and then reconstituted with 1 mL of concentrated HNO3. They were then evaporated to near dryness again and reconstituted with 2 mL of 2% HNO3. The concentration of Pa in the eluent was then measured using ICP-MS. 233 Pa / 231 Pa isotope ratio, Th in the eluent 229 Th / 230 Th isotope ratio.

[0087] exist 230 Th- 234 In the U-model, due to 229 The amount of the diluent is known, so it is determined by measurement. 229 Th / 230 The Th isotope ratio can be used to determine the content of uranium octoxide in the U850 standard sample.230 The number of Th atoms. Then, based on this... 230 The number of atoms of Th (equivalent to the number in formula (1)) N 2') and the measurements obtained above 234 The number of atoms of U (equivalent to the number in formula (1)) N 1'), according to formula (1), the value in formula (1) can be calculated. t ', that is, based on 230 Th- 234 The age of the U850 uranium octoxide standard sample obtained from the U-model was determined. The results show that the age of the U850 uranium octoxide standard sample is 67.33 years, which leads to a production date of January 26, 1958. Figure 5 and Figure 6 The text shows the process of passing through... 230 Th- 234 The process of calculating the age of the U850 uranium octoxide standard sample using the U-model.

[0088] exist 231 Pa- 235 In the U-model, due to 233 The amount of Pa diluent is known, so it is determined by measurement. 233 Pa / 231 The Pa isotope ratio can be used to determine the content of uranium octoxide in the U850 standard sample. 231 The amount of Pa. Then, based on that... 231 The amount of Pa (equivalent to the amount in formula (2)) N 3) and the measurements obtained above 235 The quantity of U (equivalent to the value in formula (2)) N 1) According to formula (2), the value in formula (2) can be calculated. t That is, based on 231 Pa- 235 The age of the U850 uranium octoxide standard sample obtained from the U-model was determined. The results show that the age of the U850 uranium octoxide standard sample is 66.85 years, which leads to a production date of July 17, 1958. Figure 7 and Figure 8 The text shows the process of passing through... 231 Pa- 235 The process of calculating the age of the U850 uranium octoxide standard sample using the U-model.

[0089] The ages and estimated production times of the same uranium material U850 obtained by measuring using two models, as well as the reference production time of U850, are summarized in Table 1 below.

[0090] Table 1

[0091] The above measurement results show that the uranium age measurement method of this application successfully measured the ages of two models of U850 simultaneously using the same sample. The age measurement results of the two models are in high agreement with the reference production time of U850, indicating that the method of simultaneously measuring the ages of two models of uranium material in this application has high reliability.

[0092] The above description is only a preferred embodiment of this application and does not limit the patent scope of this application. All equivalent structural transformations made using the content of this application's specification under the inventive concept of this application, or direct / indirect applications in other related technical fields, are included within the patent protection scope of this application.

Claims

1. A method for simultaneously measuring the ages of two models of uranium material, characterized in that, The method includes: S1: Preparation 233 Pa diluent; S2: Measure the 233 Pa diluent concentration; S3: Measuring the uranium material to be tested 234 Number of atoms of U N 1 ’ and 235 Number of atoms of U N 1; S4: Add the first amount of uranium material to be tested. 233 Pa diluent and second amount 229 Th diluent, to obtain the uranium sample to be separated, wherein... 229 The concentration of the diluent is known; S5: Use an AG1-X8 resin column to separate the Pa and Th samples from the uranium sample to be separated; S6: Measure the Pa content in the separated Pa sample. 233 Pa / 231 Pa isotope ratio and the Th sample obtained from the separation 229 Th / 230 Th isotope ratios; S7: Based on the measurements obtained in step S2 233 The concentration of Pa diluent, added in step S4 233 The first amount of Pa diluent and the amount measured in step S6 233 Pa / 231 Pa isotope ratios were calculated to obtain the content of the uranium material to be tested. 231 number of atoms of Pa N 3; S8: Based on known... 229 The concentration of the diluent, added in step S4 229 The second amount of Th diluent and the amount measured in step S6 229 Th / 230 The Th isotope ratio was used to calculate the content of th in the uranium material being tested. 230 Number of Th atoms N 2 ’ ; S9: Calculate according to formula (1) 230 Th- 234 The age of the uranium material to be tested obtained from the U-model; Official (1), In formula (1), t' indicates by 230 Th- 234 Age of uranium material obtained by the U-model λ1' represents 234 The decay constant of U, λ2' represents 230 The decay constant of Th, N2' indicates that uranium material contains 230 The number of Th atoms N1' indicates that uranium material contains 234 The number of atoms of U N2' / N1' indicates the uranium material in 230 Th / 234 U atom ratio; S10: Calculate according to formula (2) 231 Pa- 235 The age of the uranium material to be tested obtained from the U-model; Official (2), In formula (2), t represents by 231 Pa- 235 Age of uranium material obtained by the U-model λ1 represents 235 The decay constant of U, λ3 represents 231 decay constant of Pa N3 indicates that uranium material contains 231 The number of atoms in Pa. N1 indicates that uranium material contains 235 The number of atoms of U N3 / N1 indicates that in uranium materials... 231 Pa / 235 U atom number ratio.

2. The method according to claim 1, characterized in that, preparation 233 Step S1 for Pa diluent includes the following sub-steps: S11: Provides the initial Np solution; S12: Using hydrazine hydrate as a reducing agent, the Np in the initial Np solution is reduced under a temperature holding condition of 70°C to 90°C. 6+ and Np 5+ Restore to Np 4+ The valence state of Np is adjusted to Np. 4+ Reduced Np solution; S13: Separate from the reduced Np solution 233 Pa, obtained 233 Pa diluent.

3. The method according to claim 2, characterized in that, In step S13, an HPQ resin column is used with an aqueous nitric acid solution as the eluent to separate the Np from the reduced Np solution. 233 Pa, obtained 233 Pa diluent.

4. The method according to claim 3, characterized in that, The reduced Np solution was separated using an HPQ resin column with an aqueous nitric acid solution as the eluent. 233 Pa, obtained 233 The steps for applying Pa diluent include the following sub-steps: S131: The HPQ resin is pretreated by repeatedly washing it with pure water and an aqueous HNO3 solution with a concentration of 1M to 2M. S132: The pretreated HPQ resin is packed into a separation column to obtain an HPQ resin column, and then the HPQ resin column is equilibrated with an aqueous HNO3 solution of 7M to 8M concentration. S133: Load the reduced Np solution into the equilibrated HPQ resin column and collect... 233 Pa rinsing solution; S134: Elute the HPQ resin column with an aqueous HNO3 solution of 4.5M to 5.5M concentration, and then further collect... 233 Pa eluent, and the solution collected in step S133 233 The Pa eluents were combined to obtain 233 Pa diluent.

5. The method according to claim 1, characterized in that, Measure the 233 Step S2, which determines the concentration of Pa diluent, includes the following sub-steps: S21: Measuring the concentration of uranium in uranium standard samples of known age using isotope dilution mass spectrometry. 235 U / 233 U isotope ratios were used to obtain the uranium standard sample. 235 The number of atoms of U; S22: Based on the known age t of the uranium standard sample, the measured... 235 The number of U atoms in the uranium standard sample is calculated using the formula (2). 231 The number of atoms in Pa; S23: The third amount prepared in step S1 233 Pa diluent is added to the HNO3 aqueous solution of the uranium standard sample to obtain the uranium standard sample solution to be separated; S24: Use an AG1-X8 resin column to separate the Pa sample from the uranium standard sample solution to be separated; S25: Measure the Pa sample obtained in step S24. 233 Pa / 231 Pa isotope ratios; S26: Based on the uranium standard sample obtained in step S22... 231 The number of atoms of Pa and the measurements obtained in step 25 233 Pa / 231 Pa isotope ratios were calculated. 233 The number of atoms of Pa, and then based on that calculation... 233 The number of atoms of Pa and the third quantity are used to calculate the... 233 Pa is the concentration of the diluent.

6. The method according to claim 5, characterized in that, Step S24, which involves separating the Pa sample from the uranium standard sample solution using an AG1-X8 resin column, includes the following sub-steps: S241: The AG1-X8 resin is pretreated by repeatedly washing it with pure water and an HNO3 aqueous solution with a concentration of 1M to 2M. S242: The pretreated AG1-X8 resin is packed into a separation column to obtain an AG1-X8 resin column, and then the AG1-X8 resin column is equilibrated with an HCl aqueous solution of 8M to 10M. S243: Load the uranium standard sample solution to be separated into an equilibrated AG1-X8 resin column; S244: Elute the AG1-X8 resin column with an HCl aqueous solution of 8M to 10M to remove impurities; S245: Elute the AG1-X8 resin column with an aqueous solution of HCl with a concentration of 8M to 10M and HF with a concentration of 0.01M to 1M to elute Pa, and obtain Pa eluent as Pa sample.

7. The method according to any one of claims 1 to 6, characterized in that, In step S3, isotope dilution mass spectrometry is used to measure the concentration of uranium in the analyte. 234 Number of atoms of U N 1 ’ and 235 Number of atoms of U N 1.

8. The method according to any one of claims 1 to 7, characterized in that, Step S5, which uses an AG1-X8 resin column to separate the Pa and Th samples from the uranium sample to be separated, includes the following sub-steps: S51: The AG1-X8 resin is pretreated by repeatedly washing it with pure water and an HNO3 aqueous solution with a concentration of 1M to 2M. S52: The pretreated AG1-X8 resin is packed into a separation column to obtain an AG1-X8 resin column, and then the AG1-X8 resin column is equilibrated with an 8M to 10M HCl aqueous solution. S53: Load the uranium sample to be separated into a balanced AG1-X8 resin column; S54: Elute the AG1-X8 resin column with an HCl aqueous solution of 8M to 10M to obtain Th eluent, which is used as the Th sample; S55: Elute the AG1-X8 resin column with an aqueous solution of HCl with a concentration of 8M to 10M and HF with a concentration of 0.01M to 1M to elute Pa, and obtain Pa eluent as Pa sample.

9. The method according to any one of claims 1 to 8, characterized in that, In step S6, inductively coupled plasma mass spectrometry (ICP-MS) is used to measure the concentration of Pa in the separated Pa sample. 233 Pa / 231 Pa isotope ratio and the Th sample obtained from the separation 229 Th / 230 Th isotope ratio.

10. The method according to any one of claims 1 to 9, characterized in that, The first amount of uranium material to be tested was added. 233 Pa diluent and second amount 229 Before step S4 of the Th diluent step, there is also a step of dissolving the uranium material to be tested in an aqueous HNO3 solution with a concentration of 5M to 7M.

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