VOLUME 19 (Supplement)

Accurate determination of major and trace elements in nuclear source materials using X-ray fluorescence spectrometry

Reliable characterization of nuclear source materials requires rapid and defensible methods for measuring major oxides and selected trace elements. This study evaluated portable X-ray fluorescence spectrometry (pXRF) and wavelength-dispersive X-ray fluorescence spectrometry (WDXRF) for geochemical analysis of materials relevant to nuclear source material assessment. Twenty-one certified reference materials, including igneous rocks, sedimentary rocks, sediments, and mineralized reference materials, were prepared as pressed powder pellets and analyzed using a Bruker S1 Titan pXRF and a Rigaku Supermini 200 WDXRF. Calibration performance was assessed by comparing measured and certified values using reporting coverage, linear regression, slope, intercept, and coefficient of determination (R2). For pXRF, manufacturer-provided detection limits and analysis ranges were used as screening references, while WDXRF was evaluated using CRM-based empirical calibration. The pXRF method showed good calibration performance for Cr, Ba, Cu, Ni, Pb, Rb, Sr, Y, Zn, Ca, Fe, K2O, Ti, and Mn, but had insufficient reporting coverage for Nb, Th, U, and V, and poor performance for S, MgO, and P. WDXRF showed stronger performance for major oxides and good calibration for several selected trace elements, including Cr, Cu, Ni, Rb, S, Sr, V, Y, Zn, and Zr. Overall, WDXRF is preferred for quantitative major-oxide analysis and selected elements such as S, V, and Zr, whereas pXRF is useful for rapid screening of selected trace elements. For U and Th, more sensitive complementary techniques such as ICP-MS/MS are recommended.