Sample screening of uranium ore concentrates using portable spectrophotometers: investigating the correlation between visible colors and chemical signatures

A research collaboration between the Japan Atomic Energy Agency and the Department of Energy’s National Nuclear Security Administration examined nuclear forensic signatures and analytical methods for tracing the origins of uranium ore concentrates (UOCs). Here, this study focuses on utilizing portable spectrophotometers capable of reflectance measurements in the visible light spectrum as a potential rapid screening tool for nuclear forensics analysis. Unlike laboratory-based near-infrared spectroscopy or digital image analysis, this research investigated the potential to correlate visible color measurements with key nuclear forensics signatures using seven types of UOC samples with known origins and three UOC certified reference materials. Results demonstrated that distinct color groups, quantified using CIELAB values, correlated with major uranium compounds. Furthermore, the findings indicated that trace elements can influence the UOC colors, providing additional insights into material characteristics. Although this approach requires further validation across a broader range of UOC species, this study demonstrated that simple colorimetric analysis using visible spectrophotometry, which does not require complex sample preparation or data processing, can serve as a practical and novel rapid tool for preliminary screening and attribution in nuclear forensics investigations.. Authors: Kimura, Yoshiki [Japan Atomic Energy Agency (JAEA), Tokai (Japan)] (ORCID:0009000133476043); Shollenberger, Quinn R. [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)]; Matsumoto, Tetsuya [Japan Atomic Energy Agency (JAEA), Tokai (Japan)]; Lindvall, Rachel [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)]; Hoffman, Derek [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)]. DOE Contract: AC52-07NA27344. Subjects: and nuclear chemistry; radiochemistry; Chemistry - Radiation chemistry; Colorimetry; Nuclear Forensics; Uranium Ore Concentrate