ウラン科学研究者が意図的核鑑識の実現可能性を調査(Uranium science researchers investigate feasibility of intentional nuclear forensics)

2024-06-26 オークリッジ国立研究所(ORNL)

A sample of finchite, a uranium mineral discovered by Oak Ridge National Laboratory scientist Tyler Spano and collaborators at the United States Geological Survey, is examined with a light scattering technique known as Fourier-infrared spectroscopy. Credit: Jeff Otto/ORNL, U.S. Dept. of Energy

＜関連情報＞

• https://www.ornl.gov/news/uranium-science-researchers-investigate-feasibility-intentional-nuclear-forensics
• https://www.sciencedirect.com/science/article/abs/pii/S0022311523005548?via%3Dihub

意図的な核鑑識のための燃料サイクル初期のタグガント組み込みの構造的特徴 Structural features of early fuel cycle taggant incorporation for intentional nuclear forensics

Tyler L. Spano, Toya N. Beiswenger, Benjamin T. Manard, Tash L. Ulrich, Rodney Hunt, Andrew Miskowiec, Ashley E. Shields  Available online: 17 October 2023
DOI:https://doi.org/10.1016/j.jnucmat.2023.154787

Abstract

To develop strategies for incorporating transition metal taggants (Fe, Cr, and Ni) into oxide fuels and to understand how these taggant candidates persist through early fuel cycle processes, synthetic procedures are modified from established production routes to yield intentionally tagged early fuel cycle intermediates including uranyl nitrate hexahydrate (UNH, UO₂(NO₃)₂·6H₂O), uranyl peroxide tetrahydrate (studtite, UO₂O₂·4H₂O), and uranyl peroxide dihydrate (metastudtite, UO₂O₂·2H₂O). First, Fe, Cr, and Ni nitrate solutions are introduced to an aqueous solution of UNH followed by precipitation to produce tagged UNH. Then, studtite is precipitated from UNH followed by dehydration to metastudtite. Structural influences of taggant incorporation within all synthesized phases are investigated using powder X-ray diffraction (PXRD) and Raman spectroscopy to provide insight into crystallographic modifications resulting from the addition of tags to these early fuel cycle materials and elucidate the chemical form of taggants introduced at these stages. The possibility of segregation of taggant species into discrete phases within U matrices was examined using scanning electron microscopy with energy dispersive X-ray spectroscopy. Taggant concentrations in solid-phase materials were determined using inductively coupled plasma-optical emission spectroscopy. Observations from Raman spectroscopy and PXRD indicate that introducing transition metal tags during uranyl nitrate precipitation results in potential impurity phase segregation in UNH, but transition metal incorporation is suggested by results for tagged uranyl peroxide materials. Results from this study will inform strategies for optimizing taggant incorporation in UO₂.