Certification of uranium isotope amount ratios in a suite of uranium ore concentrate certified reference materials

Zhang, R.*; Nadeau, K.*; Gautier, E. A.*; Babay, P. A.*; Ramella, J. L.*; Virgolici, M.*; Serban, A. E.*; Fugaru, V.*; 木村 祥紀; Venchiarutti, C.*; et al.

Geostandards and Geoanalytical Research, 46(1), p.43 - 56, 2021/11

https://doi.org/10.1111/ggr.12409

In this study, data from thirteen laboratories from around the world are presented for a successful certification of uranium isotope ratios in uranium ore concentrate certified reference materials from the National Research Council Canada. Different mass spectrometric techniques (including SF-ICPMS, q-ICM-MS, TIMS, MC-ICP-MS, SIMS, and AMS) and analytical methods were employed. In general, the reported data from all sources exhibit good consistency, and as expected TIMS and MC-ICP-MS showed superior performances. The three candidate uranium ore concentrate CRMs, UCLO-1, UCHI-1, and UPER-1, have natural uranium isotope ratios with certified values of 0.5304(7)10, 0.5475(2)10, and 0.5361(4)10 for n(U)/n(U) and 0.007 2563(13), 0.007 2563(10), and 0.007 2542(11) for n(U)/n(U), respectively, with expanded uncertainty (k=2) applicable to the last digit of the value given in the parentheses. Information values for n(U)/n(U) in these three CRMs, measured by AMS, are also provided: 1010, 210, and 2210. The uncertainties of the proposed certified values of uranium isotope ratios in uranium ore concentrate CRMs are superior to available reference materials and the values of n(U)/n(U) and n(U)/n(U) show significant variation among the three CRMs.