The same rare earth element patterns are observed for ore concentrate samples (S2-S5) as in the parent ore body (WY Roll Front). The REE signatures obtained for UOC and uraninite are not impacted by sampling strategy or instrument used for analysis. (Spano et al., Trace element and isotopic analysis of uranium ore concentrates: applications for nuclear forensic analysis. Applied Geochemistry. In revision. 

Uranyl Vanadate Crystal Chemistry

Thermodynamic and crystal chemical investigations of uranyl vanadate minerals resulted in development of charge deficiency per anion (NCDA). This quantity relates bonding requirements of the structural units and interstitial complexes in minerals to thermodynamic stability. An exponential correlation is observed between NCDA  of carnotite, curienite, and francevillite and energetic stability (enthalpy of formation from binary oxides) for the studied minerals.  The number of occurrences of uranyl vanadate mineral species are found to correlate with both enthalpy of formation from oxides, and NCDA. (Spano et al., Thermodynamic investigation of uranyl vanadate minerals: implications for structural stability. American Mineralogist. In Press.)

Deposit type average chondrite normalized rare earth element signatures for important uranium deposit types. Using linear regression analysis, the degree of similarity between a U-rich material of unknown origin and established U deposit type can be quantified. (Spano et al. A novel nuclear forensic tool involving deposit type normalized rare earth element signatures. Terra Nova. In Press.)

selected skills and techniques

Uranyl vanadate minerals are amongst the most insoluble uranium alteration minerals.  They are significant ore source for U and V. These minerals are composed of sheet structures which are capable of capturing and retaining diverse cation species. Changing the cation occupancy of these materials leads to unique and tunable structural characteristics.  Understanding crystal chemical changes as related to thermodynamic properties enables prediction of stable structural arrangements. This research seeks to provide a fundamental understanding of materials relevant to the nuclear fuel cycle.

​Crystallographic Techniques and Software

•Single crystal X-ray Diffraction
•Powder X-ray Diffraction
•Small angle X-ray Scattering

•Bruker SHELX
•FullProf Suite
•Powder Diffraction File (PDF4)

Analytical Chemistry Techniques

•Raman Spectroscopy
•Infrared Spectroscopy
•Inductively Coupled Plasma Optical Emission Spectrometry
•Inductively Coupled Plasma Mass Spectrometry

•Multicollector Inductively Coupled Plasma Mass Spectrometry

•X-ray Fluorescence Spectroscopy
•Electron Microprobe Analysis
•Scanning Electron Microscopy
•Thermogravimetric Analysis

Synthetic Chemistry Techniques

•Hydrothermal Synthesis
•Solid-state Synthesis

Other Skills

•Geologic Thin Section Preparation
•Petrographic Microscopy
•Reflected Light Microscopy
•Handling of Radioactive Materials

Nuclear Forensics

Yellowcake, or uranium ore concentrate (UOC) represents an important intermediate product in the nuclear fuel cycle. 

Nuclear material may be intercepted for malicious purposes at various stages throughout the nuclear fuel cycle. Can we determine the origin of uranium-rich materials after chemical and mechanical processing?

​Inductively coupled plasma mass spectrometry (ICP-MS) analytical techniques are used to quantify trace element concentrations. How do sample introduction methods and instrumental differences affect obtained trace element signatures? 

Identifying the origin of uranium-rich materials is a critical objective of nuclear forensic analysis. Rare earth element (REE) distributions within uranium ores are well-established forensic indicators, We have developed average chondrite normalized (CN)-REE signatures for important U deposit types worldwide that are employed to evaluate U ore paragenesis using a simple linear regression analysis. This technique provides a straightforward method that can aid in determining the deposit type of U ores based on their REE abundances, and combined with other forensic indicators can provide essential provenance information for nuclear materials.