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A Study on the Uncertainty of Radiochronometry Based on Bateman Equation
- 언어ENG
- URLhttps://db.koreascholar.com/Article/Detail/430946
Nuclear Forensics is recognized as a essential component in the nuclear non-proliferation verification sector by the international community. It is being advanced under the leadership of the IAEA, the U.S., and the EU. Both the U.S.’s Lawrence Livermore National Laboratory (LLNL) and the international collaborative organization, the Nuclear Forensics International Technical Working Group (ITWG), have proposed to establish a relationship between the production timing and radiochronometry of nuclear materials or samples to utilize in the field of nuclear forensics. Radiochronometry of nuclear materials is calculated based on the Bateman equation, incorporating factors with uncertainties derived from tests, experiments, and analyses. The results from the nuclear activity radiochronometry also encompass uncertainties, affecting their reliability. This study examined the mathematical uncertainty calculations related to the results of nuclear activity radiochronometry, focusing on calculation methods, contribution rates per factor, and sensitivities. Uncertainty factors for the Bateman equation-based radiochronometry were observed in the decay constants for each nuclide type and the uncertainty in the radioactive ratio of the tracer nuclide. The sensitivity for each factor revealed that the uncertainty in the radioactive ratio of the signature nuclide contributed more significantly than the uncertainty in decay constants for each nuclide type. Each factor displayed a distinct sensitivity curve relative to the radioactive ratio. As it approaches a radioactive equilibrium, the sensitivity tends to increase infinitely, indicating a corresponding trend of infinite increase in uncertainty. Because the time and curve shape to reach radioactive equilibrium vary depending on the signature nuclide, it’s essential to choose an appropriate signature nuclide based on the anticipated period and analysis requirements for nuclear activity radiochronometry. However, radiochronometry using mathematical methods is limited to the relationship between parent and daughter nuclides, presenting the potential for underestimation of uncertainty factors like decay constants. Future research will need to focus on uncertainty calculation methods through computational simulations, especially using the Monte Carlo method, to overcome the limitations of mathematical approaches and potential underestimations.
