Nuclear forensic analysis of an unknown uranium ore concentrate sample seized in a criminal investigation in Australia

Abstract

Early in 2009, a state policing agency raided a clandestine drug laboratory in a suburb of a major city in Australia. During the search of the laboratory, a small glass jar labelled "Gamma Source" and containing a green powder was discovered. The powder was radioactive. This paper documents the detailed nuclear forensic analysis undertaken to characterise and identify the material and determine its provenance. Isotopic and impurity content, phase composition, microstructure and other characteristics were measured on the seized sample, and the results were compared with similar material obtained from the suspected source (ore and ore concentrate material). While an extensive range of parameters were measured, the key 'nuclear forensic signatures' used to identify the material were the U isotopic composition, Pb and Sr isotope ratios, and the rare earth element pattern. These measurements, in combination with statistical analysis of the elemental and isotopic content of the material against a database of uranium ore concentrates sourced from mines located worldwide, led to the conclusion that the seized material (a uranium ore concentrate of natural isotopic abundance) most likely originated from Mary Kathleen, a former Australian uranium mine.

Nuclear Forensic Science: Analysis of Nuclear Material Out of Regulatory Control

“…Despite this progress, no single parameter has yet been identified that is able to discern the identity and origin of unknown UOC samples. Increasingly, combined isotopic fingerprinting approaches are used to constrain the provenance and processing history of samples, and multivariate statistical techniques are used to discriminate between different sources of UOCs (Keegan et al 2008(Keegan et al , 2012(Keegan et al , 2014Bayne et al 2009;Robel et al 2009Robel et al , 2011Sirven et al 2009;Varga et al 2010). Likewise, approaches to chronometry have evolved over time, toward an increasing emphasis on obtaining concordant results from multiple parent, daughter, and granddaughter systems.…”

“…The second sample yielded a model production date of ∼1962, unexpectedly old but plausible (within the nuclear era). A second Australian seizure occurred in New South Wales (Keegan et al 2014), where a small glass jar labeled "Gamma Source" and containing a green powder was obtained. As with the previous seizure, the sample was thoroughly analyzed at both ANSTO and LLNL for stoichiometry, trace elemental composition, U isotopic composition, particle morphology, and radiochronometry.…”

A novel nuclear forensic tool involving deposit type normalized rare earth element signatures

“…Observed partitioning of REEs in U oxides appears to be strongly dependent on temperature, fluid chemistry and element availability (hypogene REE source), and thus these elements have been used extensively as forensic indicators (e.g. Fayek, ; Frimmel et al., ; Keegan, Wallenius, Mayer, Varga, & Rasmussen, ; Keegan et al., ; Mayer, Wallenius, & Fanghänel, ; Mayer, Wallenius, & Varga, ; Mercadier et al., ). At high temperatures, particularly above 350°C, incorporation mechanisms that discriminate against available cations based upon size are negated due to the dilational nature of the uraninite structure; this results in a relatively flat CN‐REE pattern (Mercadier et al., ).…”

Development of small particle speciation for nuclear forensics by soft X-ray scanning transmission spectromicroscopy

“…9 Isotopic content and trace element impurities can be correlated with process history, and in some cases can provide information on the possible geographic origin of a specimen. [10][11][12][13] Data from a broad array of analytical methods are typically needed to completely characterize a forensic specimen, with each measurement providing a different constraint on the possible process history and origin. Techniques applied in the literature include mass spectrometry, nuclear counting, X-ray fluorescence, and powder X-ray diffraction.…”

“…Past studies of illicit nuclear material have required a combination of rapid analyses at several different facilities to rule out possible origins of the material. [10][11] Here, technical developments in sample preparation and instrument operation at the Molecular Environmental Science (MES) STXM Beamline 11.0.2 of the Advanced Light Source (ALS) are described, with a focus on improved utility and throughput for heterogeneous forensic specimens. Initial results are presented, including baseline spectra acquired from common uranium materials, demonstrations of STXM speciation capability on mixtures of known particulates, and preliminary studies of forensic specimens.…”