The various uses and applications of nuclear forensic science are examined. Nuclear forensic science is especially useful in determining the isotopic makeup, morphology and chemical purification of ...uranium and plutonium, among other applications.
Lead and strontium isotope ratios were used for the origin assessment of uranium ore concentrates (yellow cakes) for nuclear forensic purposes. A simple and low-background sample preparation method ...was developed for the simultaneous separation of the analytes followed by the measurement of the isotope ratios by multicollector inductively coupled plasma mass spectrometry (MC-ICPMS). The lead isotopic composition of the ore concentrates suggests applicability for the verification of the source of the nuclear material and by the use of the radiogenic 207Pb/206Pb ratio the age of the raw ore material can be calculated. However, during data interpretation, the relatively high variation of the lead isotopic composition within the mine site and the generally high contribution of natural lead as technological contamination have to be carefully taken into account. The 87Sr/86Sr isotope ratio is less prone to the variation within one mine site and less affected by the production process, thus it was found to be a more purposeful indicator for the origin assessment and source verification than the lead. The lead and strontium isotope ratios measured and the methodology developed provide information on the initial raw uranium ore used, and thus they can be used for source attribution of the uranium ore concentrates.
A novel and simple analytical procedure has been developed for the trace-level determination of lanthanides (rare-earth elements) in uranium-bearing materials by inductively coupled plasma ...sector-field mass spectrometry (ICP-SFMS). The method involves a selective extraction chromatographic separation of lanthanides using TRU™ resin followed by ICP-SFMS analysis. The limits of detection of the method proposed is in the low pg
g
−1 range, which are approximately two orders of magnitude better than that of without chemical separation. The method was validated by the measurement of reference material and applied for the analysis of uranium ore concentrates (yellow cakes) for nuclear forensic purposes, as a potential application of the methodology.
In the context of nuclear security, uranium ore concentrates (UOCs) play an important role: they are traded in large quantities and this makes their use “out of regulatory control” a possible ...scenario.
Once an incident of illicit trafficking o f n uclear m aterial is detected, an understanding of its origin and production process is required; this implies the necessity to use analytical techniques able to measure characteristic parameters (e.g. physical, chemical, isotopic characteristics of the nuclear materials) which are referred to, in the field o f t he n uclear f orensics, a s signatures.
The present study investigates the potential of image texture analysis (i.e. the angle measure technique), combined with the spectrophotometric determination of colours for the evaluation of the origin of several UOCs. The use of different multivariate statistical techniques allows the categorization of about 80 different samples into a few groups of UOCs powders, which makes this approach a promising method complementing the already established methods in nuclear forensics.
Nuclear forensics is a relatively young discipline in science which aims at providing information on nuclear material of unknown origin. The determination of characteristic parameters through ...tailored analytical techniques enables establishing linkages to the material's processing history and hence provides hints on its place and date of production and on the intended use.
The aim of the present work was to develop a direct method for age dating (production date measurement) of uranium samples by laser ablation multi-collector inductively coupled plasma mass ...spectrometry (LA-MC-ICP-MS) by the measurement of the
230
Th/
234
U ratio. The major instrumental conditions and sample characteristics affecting the accuracy and precision were investigated in this systematic study. By comparing the obtained LA-MC-ICP-MS results with those obtained after chemical separation measurements, it shows that the LA-MC-ICP-MS method is capable to produce accurate results for pure highly enriched uranium. Natural and low-enriched uranium, however, needs a higher mass resolution to remove the identified interferences, which can lead to erroneous results.
Laser ablation multi-collector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS) was used to study the heterogeneity of solid uranium materials. Using spatially resolved isotope ratio ...measurement, the degree of isotopic homogeneity at micron-level could be assessed in nuclear samples for nuclear safeguards and forensics purposes. LA-MC-ICP-MS was applied for two UO2 pellets which had been distributed in the 5th Collaborative Materials Exercise (CMX-5) organized by the Nuclear Forensics International Technical Working Group (ITWG). The two materials in question have very similar 235U isotope abundance (around 1%), but very different 235U isotopic heterogeneity. Although both UO2 pellets were prepared from identical source materials (mixture of depleted 0.3% and low-enriched 4.3% 235U), their different production routes resulted in observable differences at micron-scale. By the spatially resolved measurement the number of constituting components (feed materials) with different uranium enrichment and their n(234U)/n(238U) and n(235U)/n(238U) isotope ratios could be determined. Imaging can help assess the lateral dimensions of the individual components (grains) and may indicate a certain production route. This information on the inhomogeneity, the possible inference on the production process and isotopic composition of the constituents are highly valuable in nuclear forensics investigations for determining the origin of an unknown nuclear material.
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•Spatial inhomogeneity in U materials for nuclear forensics was studied by LA-MC-ICP-MS.•It can distinguish heterogeneous samples with same bulk 235U enrichment at micron-level.•The number of the starting materials and respective U enrichment can be determined.•2D-imaging of nuclear forensic materials was developed.
The present work describes a method for the preparation and validation of plutonium age dating reference materials. The test samples prepared in this context could be used to validate experimental ...protocols for determining the production date of plutonium via the 234U/238Pu, 235U/239Pu, 236U/240Pu, and 241Am/241Pu chronometers. The starting material was prepared using reactor-grade plutonium, which was purified using a dedicated method to guarantee high Pu recovery, while maximizing U and Am separation efficiencies. The U and Am separation factors were determined by the addition of high-amounts of 233U and 243Am spikes and their remeasurement in the final product. The prepared material is intended for quality control and assessment of method performance in nuclear forensics and safeguards.
Employing laser ablation multi-collector ICP-MS (LA-MC-ICP-MS), its potential for evaluating the homogeneity of solid uranium (U) bearing materials was investigated. To this end, the n(235U)/n(238U) ...ratio of two low-enriched U certified reference materials (CRMs), i.e. powdered standard reference material U-010 (~1wt% 235U) and a UO2 pellet of CRM 125-A (~4wt% 235U) was determined using line scan analysis. Four spots of 5μm diameter each were ablated per second with the LA system moved at a speed of 20μms−1 for several minutes. Experimental and certified U isotope ratios matched perfectly, unequivocally validating the accuracy of the applied analytical methodology. In addition, the narrow and symmetric frequency distribution of the n(235U)/n(238U) ratio of both CRMs confirmed their homogeneity with respect to the U isotopic composition. Utilizing LA-MC-ICP-MS line scan analysis of two similar UO2 pellets (~1wt% 235U) from the 5th Collaborative Materials Exercise (CMX-5) revealed diverse inhomogeneity regarding their n(235U)/n(238U) ratio. Although both UO2 pellets used for the CMX-5 exercise were prepared from identical source materials, their different production routes yielded largely contrasting frequency distributions of the n(235U)/n(238U) ratio. While 235U isotope abundance ranged from 0.75%–1.6% for the first pellet, this value fluctuated between 0.45% and 3.0% for the second pellet. This specific information sheds additional light on the production process of these materials and is helpful in nuclear forensics investigations when determining the origin of unknown nuclear material. The depleted nature (~0.4wt% 235U) of two seized U metal samples was established through LA-MC-ICP-MS analysis of the n(235U)/n(238U) ratio. As black and yellow regions within both U bearing samples had identical U isotopic composition, the observed colour differences might arise from different degrees of U oxidation and are not associated with U isotopic inhomogeneity within the material. The significantly different 235U abundance of the two samples (0.3670±0.0015 wt.% and 0.4146±0.0013 wt.%), however, clearly indicates they were prepared from different source materials and/or from diverse amounts of them.
•Accurate and precise n(235U)/n(238U) ratios are obtained for U bearing materials employing LA-MC-ICP-MS.•Excellent agreement of U isotope ratios between laser-based and solution-based MC-ICP-MS analysis as well as certified values.•Using line scan analysis, the U isotopic (micro-)homogeneity of solid UO2 pellets can be assessed quickly.•Two UO2 pellets prepared from identical source materials had diverse distribution of their U isotopic composition.•Differently coloured regions within samples revealed identical U isotopic composition reflecting diverse oxidation states of U.
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