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CN-121994949-A - Method for simultaneously measuring ages of two models of uranium material

CN121994949ACN 121994949 ACN121994949 ACN 121994949ACN-121994949-A

Abstract

The application provides a method for simultaneously measuring ages of two models of uranium materials, which comprises the steps of preparing 233 Pa diluents, measuring concentrations of 233 Pa diluents, measuring atomic numbers N 1 'and N 1 of 234 U and 235 U in the uranium materials to be measured, adding a first amount of 233 Pa diluents and a second amount of 229 Th diluents with known concentrations into the uranium materials to be measured to obtain uranium samples to be separated, separating Pa samples and Th samples from the uranium samples to be separated by using AG1-X8 resin columns, measuring 229 Th/ 230 Th in 233 Pa/ 231 Pa and Th samples in the Pa samples, calculating atomic numbers N 3 and N 2 ' of 231 Pa atoms N 3 and 230 Th in the uranium materials to be measured, and calculating ages of the uranium materials to be measured according to a formula (1) and a formula (2) respectively. The method can measure the ages of two models 230 Th- 234 U and 231 Pa- 235 U at the same time, and can reduce the dosage of uranium materials. The ages obtained by the two models are comparable and can be used to evaluate the accuracy of the measured ages. Formula (1) Formula (2)

Inventors

  • HE HUAN
  • XU CHANGKUN
  • ZHAO YONGGANG
  • HU RUIXUAN
  • HUANG SHENGHUI
  • CHEN YAN
  • LIU QIAN
  • YANG QI
  • SHEN YAN
  • WANG FAN
  • ZHAO XINGHONG

Assignees

  • 中国原子能科学研究院

Dates

Publication Date
20260508
Application Date
20260104

Claims (10)

  1. 1. A method for simultaneously measuring the ages of two models of uranium material, the method comprising: S1, preparing 233 Pa diluent; s2, measuring the concentration of the 233 Pa diluent; s3, measuring the atomic number N 1 ' of 234 U and the atomic number N 1 of 235 U in the uranium material to be measured; S4, adding a first amount of 233 Pa diluent and a second amount of 229 Th diluent into the uranium material to be separated to obtain a uranium sample to be separated, wherein the concentration of the 229 Th diluent is known; s5, separating a Pa sample and a Th sample from uranium samples to be separated by using AG1-X8 resin columns; S6, measuring 233 Pa/ 231 Pa isotope ratio in the separated Pa sample and 229 Th/ 230 Th isotope ratio in the separated Th sample; S7, calculating to obtain the atomic number N 3 of 231 Pa in the uranium material to be detected according to the concentration of 233 Pa diluent measured in the step S2, the first amount of 233 Pa diluent added in the step S4 and the 233 Pa/ 231 Pa isotope ratio measured in the step S6; S8, calculating to obtain the atomic number N 2 ' of 230 Th in the uranium material to be detected according to the known concentration of 229 Th diluent, the second amount of 229 Th diluent added in the step S4 and the 229 Th/ 230 Th isotope ratio measured in the step S6; s9, calculating the age of the uranium material to be detected obtained by the 230 Th- 234 U model according to the formula (1); formula (1), In the case of the formula (1), T' represents the age of the uranium material obtained from the 230 Th- 234 U model, Lambda 1 ' represents the decay constant of 234 U, Lambda 2 ' represents the decay constant of 230 Th, N 2 ' represents the atomic number of 230 Th in the uranium material, N 1 ' represents the atomic number of 234 U in uranium material, N 2 '/N 1 ' represents 230 Th/ 234 U atomic number ratio in uranium material; S10, calculating the age of the uranium material to be detected obtained by a 231 Pa- 235 U model according to a formula (2); Formula (2), In the formula (2) of the present invention, T represents the age of the uranium material obtained from the 231 Pa- 235 U model, Lambda 1 represents the decay constant of 235 U, Lambda 3 represents the decay constant of 231 Pa, N 3 represents the atomic number of 231 Pa in uranium materials, N 1 represents the atomic number of 235 U in uranium material, N 3 /N 1 represents the 231 Pa/ 235 U atomic ratio in uranium material.
  2. 2. The method according to claim 1, characterized in that the step S1 of preparing 233 Pa of diluent comprises the following sub-steps: s11, providing a starting Np solution; S12, reducing Np 6+ and Np 5+ in the initial Np solution into Np 4+ by using hydrazine hydrate as a reducing agent under the heat preservation condition of 70-90 ℃ to obtain a reduced Np solution with the valence state of Np regulated to Np 4+ ; s13, separating 233 Pa from the reduced Np solution to obtain 233 Pa diluent.
  3. 3. The method according to claim 2, wherein in step S13, 233 Pa is separated from the reduced Np solution using an HPQ resin column with aqueous nitric acid as a eluent to yield 233 Pa of diluent.
  4. 4. A method according to claim 3, wherein the step of separating 233 Pa from the reduced Np solution using an HPQ resin column with an aqueous nitric acid solution as a eluent, to obtain a 233 Pa diluent comprises the sub-steps of: S131, cleaning HPQ resin for a plurality of times by using pure water and HNO 3 aqueous solution with the concentration of 1M to 2M so as to pretreat the HPQ resin; S132, loading the pretreated HPQ resin into a separation column to obtain an HPQ resin column, and balancing the HPQ resin column by using HNO 3 aqueous solution with the concentration of 7M to 8M; S133, loading the reduced Np solution into an equilibrated HPQ resin column and taking 233 Pa eluent; S134, leaching the HPQ resin column by using an HNO 3 aqueous solution with the concentration of 4.5M to 5.5M, further taking 233 Pa leaching solution, and combining the leaching solution with the leaching solution of 233 Pa, which is taken in the step S133, so as to obtain 233 Pa diluent.
  5. 5. The method according to claim 1, characterized in that the step S2 of measuring the concentration of the 233 Pa diluent comprises the following sub-steps: S21, measuring 235 U/ 233 U isotope ratio in a uranium standard sample of known age by using isotope dilution mass spectrometry to obtain 235 U atomic number in the uranium standard sample; S22, calculating the atomic number of 231 Pa in the uranium standard sample by using the formula (2) based on the known age t of the uranium standard sample and the atomic number of 235 U obtained by measurement; S23, adding a third amount of 233 Pa diluent prepared in the step S1 into the HNO 3 aqueous solution of the uranium standard sample to obtain a uranium standard sample solution to be separated; S24, separating a Pa sample from a uranium standard sample solution to be separated by using an AG1-X8 resin column; s25, measuring 233 Pa/ 231 Pa isotope ratio in the Pa sample obtained by separation in the step S24; S26, calculating to obtain the atomic number of 233 Pa based on the atomic number of 231 Pa in the uranium standard sample obtained in the step S22 and the 233 Pa/ 231 Pa isotope ratio measured in the step 25, and then calculating to obtain the concentration of the 233 Pa diluent based on the calculated atomic number of 233 Pa and the third quantity.
  6. 6. The method according to claim 5, characterized in that the step S24 of separating the Pa sample from the uranium standard sample solution to be separated using an AG1-X8 resin column comprises the following sub-steps: s241, cleaning AG1-X8 resin for a plurality of times by using pure water and HNO 3 aqueous solution with the concentration of 1M to 2M to pretreat AG1-X8 resin; S242, loading the pretreated AG1-X8 resin into a separation column to obtain an AG1-X8 resin column, and balancing the AG1-X8 resin column by using an aqueous HCl solution with the concentration of 8M to 10M; S243, loading the uranium standard sample solution to be separated into an equilibrated AG1-X8 resin column; S244, eluting the AG1-X8 resin column by using an aqueous HCl solution with the concentration of 8M to 10M to remove impurities; s245, eluting the AG1-X8 resin column by using an aqueous solution of HCl with the concentration of 8M to 10M and HF with the concentration of 0.01M to 1M to elute Pa, so as to obtain Pa eluent as a Pa sample.
  7. 7. The method according to any one of claims 1 to 6, characterized in that in step S3, the atomic numbers N 1 ' and N 1 of 234 U and 235 U in the uranium material to be measured are measured using isotope dilution mass spectrometry.
  8. 8. The method according to any one of claims 1 to 7, characterized in that the step S5 of separating the Pa sample and the Th sample from the uranium sample to be separated using an AG1-X8 resin column comprises the following sub-steps: S51, washing AG1-X8 resin for a plurality of times by using pure water and HNO 3 aqueous solution with the concentration of 1M to 2M to pretreat AG1-X8 resin; S52, loading the pretreated AG1-X8 resin into a separation column to obtain an AG1-X8 resin column, and balancing the AG1-X8 resin column by using an aqueous HCl solution with the concentration of 8M to 10M; S53, loading the uranium sample to be separated into an equilibrated AG1-X8 resin column; S54, eluting the AG1-X8 resin column by using an aqueous HCl solution with the concentration of 8M to 10M to obtain Th (Th) eluent as a Th sample; S55, eluting the AG1-X8 resin column by using an aqueous solution of HCl with the concentration of 8M to 10M and HF with the concentration of 0.01M to 1M to obtain Pa eluent as a Pa sample.
  9. 9. The method according to any one of claims 1 to 8, characterized in that in step S6 the 233 Pa/ 231 Pa isotope ratio in the separated Pa sample and the 229 Th/ 230 Th isotope ratio in the separated Th sample are measured using inductively coupled plasma mass spectrometry ICP-MS.
  10. 10. The method according to any one of claims 1 to 9, further comprising the step of dissolving the uranium material to be measured in an aqueous HNO 3 solution having a concentration of 5M to 7M, before the step S4 of adding the first quantity of 233 Pa diluent and the second quantity of 229 Th diluent to the uranium material to be measured.

Description

Method for simultaneously measuring ages of two models of uranium material Technical Field The application relates to the technical field of radioactive material analysis, in particular to a method for simultaneously measuring ages of two models of uranium materials. Background In the fields of radioactive material management, supervision, compliance verification, traceability analysis and the like, development of high-precision and high-sensitivity radioactive material age measurement technology is required. In tracing back the history of these materials, age is the first parameter to be measured. In judging whether radioactive materials are in compliance or not, an age measurement technology plays an important role, and the technology can provide important parameters for material traceability analysis. Therefore, developing a uranium material age measurement technique has great significance, and an effective method for measuring the uranium material age needs to be provided. Disclosure of Invention In view of the above, the application aims to provide a method for measuring the ages of uranium materials, which can simultaneously measure the ages of two models 230Th-234 U and 231Pa-235 U, can reduce the dosage of uranium materials, shortens the experimental process and time, has comparability of the ages obtained by the two models, can be used for evaluating the accuracy of the measured ages, and obtains more production process information of uranium materials. The application provides a method for simultaneously measuring ages of two models of uranium materials, the method comprising: S1, preparing 233 Pa diluent; s2, measuring the concentration of the 233 Pa diluent; s3, measuring the atomic number N 1' of 234 U and the atomic number N 1 of 235 U in the uranium material to be measured; S4, adding a first amount of 233 Pa diluent and a second amount of 229 Th diluent into the uranium material to be separated to obtain a uranium sample to be separated, wherein the concentration of the 229 Th diluent is known; s5, separating a Pa sample and a Th sample from uranium samples to be separated by using AG1-X8 resin columns; S6, measuring 233Pa/231 Pa isotope ratio in the separated Pa sample and 229Th/230 Th isotope ratio in the separated Th sample; S7, calculating to obtain the atomic number N 3 of 231 Pa in the uranium material to be detected according to the concentration of 233 Pa diluent measured in the step S2, the first amount of 233 Pa diluent added in the step S4 and the 233Pa/231 Pa isotope ratio measured in the step S6; S8, calculating to obtain the atomic number N 2' of 230 Th in the uranium material to be detected according to the known concentration of 229 Th diluent, the second amount of 229 Th diluent added in the step S4 and the 229Th/230 Th isotope ratio measured in the step S6; s9, calculating the age of the uranium material to be detected obtained by the 230Th-234 U model according to the formula (1); formula (1), In the case of the formula (1), T' represents the age of the uranium material obtained from the 230Th-234 U model, Lambda 1' represents the decay constant of 234 U, Lambda 2' represents the decay constant of 230 Th, N 2' represents the atomic number of 230 Th in the uranium material, N 1' represents the atomic number of 234 U in uranium material, N 2'/N1' represents 230Th/234 U atomic number ratio in uranium material; S10, calculating the age of the uranium material to be detected obtained by a 231Pa-235 U model according to a formula (2); Formula (2), In the formula (2) of the present invention, T represents the age of the uranium material obtained from the 231Pa-235 U model, Lambda 1 represents the decay constant of 235 U, Lambda 3 represents the decay constant of 231 Pa, N 3 represents the atomic number of 231 Pa in uranium materials, N 1 represents the atomic number of 235 U in uranium material, N 3/N1 represents the 231Pa/235 U atomic ratio in uranium material. In some embodiments, step S1 of preparing 233 Pa of diluent comprises the sub-steps of: s11, providing a starting Np solution; S12, reducing Np 6+ and Np 5+ in the initial Np solution into Np 4+ by using hydrazine hydrate as a reducing agent under the heat preservation condition of 70-90 ℃ to obtain a reduced Np solution with the valence state of Np regulated to Np 4+; s13, separating 233 Pa from the reduced Np solution to obtain 233 Pa diluent. In some embodiments, 233 Pa is separated from the reduced Np solution using an HPQ resin column with aqueous nitric acid as a eluent in step S13, resulting in a 233 Pa diluent. In some embodiments, the step of separating 233 Pa from the reduced Np solution using an HPQ resin column with an aqueous nitric acid solution as a eluent to obtain a 233 Pa diluent comprises the sub-steps of: S131, cleaning HPQ resin for a plurality of times by using pure water and HNO 3 aqueous solution with the concentration of 1M to 2M so as to pretreat the HPQ resin; S132, loading the pretreated HPQ re