STRUCTURAL FEATURES OF TRANSITION METAL INCORPORATION IN URANYL PEROXIDE MINERALS STUDTITE AND METASTUDTITE FOR INTENTIONAL NUCLEAR FORENSICS

Studtite (UO₂O2·4H₂O) and metastudtite (UO₂O₂·2H₂O) are the only known peroxide containing minerals and are important phases in both the front and back ends of the nuclear fuel cycle. Towards the goal of intentionally tagging technogenic nuclear materials for potential forensics applications, we have synthesized studtite and metastudtite mineral analogues and investigated the structural features of Cr, Fe, and Ni incorporation therein using Raman spectroscopy, powder X-ray diffraction (PXRD), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS), and inductively coupled plasma-optical emission spectroscopy (ICP-OES). Analysis of Raman spectra for tagged and untagged samples of uranyl peroxides, in tandem with results from PXRD provide insight into potential incorporation mechanisms for transition metals. SEM-EDS reveals differences in the spatial distribution of taggant elements within these synthetic mineral phases and ICP-OES was used to quantify taggant incorporation in mineral phases. Results from this work suggest that studtite and metastudtite analogues may be viable options to introduce taggants into the nuclear fuel cycle for intentional nuclear forensics.