Showing 22 results for Author: Sara E. Gilson
Sep, 2026
Journal
Actinide oxalate precipitation has been ubiquitous in nuclear processing since the 1950s due to its simplicity at laboratory and production scales as both a means of actinide purification and as a key intermediate solid phase towards oxide production. Historical processing information has emphasized the need to reduce actinides, including neptunium (Np), to the tetravalent…
Jul, 2026
Journal
This study presents a novel analytical approach for quantifying Pu(IV) in glove box environments using fiber-optic-based visible–near-infrared absorption spectroscopy in combination with partial least squares regression (PLSR) and design of experiments. The method addresses significant challenges posed by overlapping spectral features arising from Nd(III), which is a commo…
Jul, 2026
Journal
Neptunium oxalate (Np(C2O4)2·6H2O) is a historically relevant solid phase used in nuclear processing as a precursor for neptunium dioxide (NpO2). Although Np oxalate has been synthesized and used for NpO2 production for decades, the thermal decomposition mechanism of this phase remains poorly understood and has not been evaluated in over 30 years. Conflicting reports in hi…
Jul, 2026
Journal
A unique approach to remotely quantify Cm(III) (0–100 µg mL− 1) in HNO3 (1–12 M) using steady-state laser fluorescence spectroscopy and multivariate regression models was developed. Photoluminescence is amenable to remote measurements using fiber-optic cables and is sensitive to numerous lanthanide and actinide species. In-line measurements can provide feedback to support…
Jul, 2026
Journal
Neptunium dioxide (NpO2) is a key phase in nuclear material processing as a target material for the production of plutonium-238 (238Pu) and has been historically synthesized via the calcination of a Np oxalate precursor. Alternative synthesis methods for NpO2 are now more prevalent, necessitating their study and comparison with the more common oxalate route. The purpose of…
Jul, 2026
Journal
This article presents a systematic study of Pu(IV) absorbance spectral features as a function of temperature to develop an understanding of this parameter’s effect on chemometric models that can be used as online monitoring tools to support nuclear processing. The descriptive and predictive models that provide real-time feedback of these processes are usually constructed w…
Apr, 2026
Journal
The role of Np(V) concentration as a potential chemical driver of Np(V) disproportionation was investigated by probing Np redox chemistry in two different acid media using visible-near-infrared absorbance spectroscopy. In situ spectroscopy of chemically and electrochemically manipulated Np oxidation states at molar concentrations of Np underscores the difficulty in stabili…
Feb, 2026
Journal
The availability of actinide standard materials for use in nuclear safeguard applications is critical, as is thorough characterization thereof. Although accurate trace element compositions and isotopic considerations are paramount for deployment of reference standards, structural characterization is also essential towards accurately describing the chemical form and potenti…