Uncertainties achievable for uranium isotope-amount ratios: estimates based on the precision and accuracy of recent characterization measurements

Utilization of ionic liquids for preferential separation of thorium during the determination of trace metallic constituents in thorium matrix using ICP-OES

“…Accuracy and precision of traceable standards must be combined to estimate realistic uncertainties in the determination as reported either for trace element assay or isotopic abundances. 69,70 In the case of isotopic composition analysis, the authors used uranium with no enrichment, low enrichment and high enrichment. They combined the accuracy as well as precision data to evaluate the uncertainties.…”

Critical need for plutonium and uranium isotopic standards with lower uncertainties

“…During characterization of the CRMs accuracies in the range of 0.01 to 0.02% were typically achieved. 3,[36][37][38] Precision (expressed as a relative standard deviation of multiple aliquots on the same turret, %RSD) of $0.05% were achieved during the analyses presented in Fig. 2 and 3, whereas precision of $0.02% (oen 0.01% or better) were typically achieved during characterization measurements.…”

“…32 Table 2 Uncertainty contributions to uranium isotope ratios, summarized from recent characterization data (major ratios are indicated in bold) The MTE method made it possible to obtain excellent quality minor isotope ratios without compromising the accuracy and precision of the major ratio data. [32][33][34][35][36][37][38] Now, the MTE technique is fully integrated into the Thermo Fisher TRITON™ TIMS instrument soware. The MTE method allows the simultaneous determination of the major and minor isotope ratios from the same analysis.…”

“…The TE and MTE techniques yield Pu isotope ratios at least of similar if not improved quality, in terms of precision and accuracy, as the U isotope ratio measurements discussed above. 27,37 The safeguards analytical laboratory at IAEA is utilizing the TE and MTE methods extensively for routine analyses of both U and Pu safeguards samples. 38 As mentioned previously, during the NBS characterization of the Pu isotopic CRMs, the mass bias at the Pu isotopic ratios were estimated using gravimetric mixtures of high-purity uranium isotopes that were measured concurrently with the Pu standards.…”

Evaluation of Uranium-235 Measurement Techniques

“…Thermal ionization mass spectrometry (TIMS) is considered the most accurate and precise measurement method to determine isotopic composition (Mathew et al 2015). A small quantity (nanograms) of the material of interest is dispersed on a small ribbon filament.…”