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As there are no matrix-matched certified reference materials, accurate and straightforward analytical procedures for the determination of americium (Am) in non-separated spent fuels employing high resolution ICP-OES and sector field (SF-) ICP-MS were developed and cross-validated. One spent (Th,Pu)O 2 fuel and two U/Pu-based spent fuels representing different chemical and isotopic compositions were analysed for their Am content. Even though the lowest limit of detection (0.07 mg kg À1) was obtained at l ¼ 283.226 nm, the ICP-OES signal at l ¼ 408.929 nm provided the most accurate results for the analysis of the spent fuel among the six investigated Am emission wavelengths. Massive spectral interference from Th precluded the use of the l ¼ 283.226 nm emission line for Am analysis of the (Th,Pu)O 2 fuel, while other potential interferences from plutonium (Pu) and neptunium (Np) could be excluded for all the tested Am wavelengths. Employing ICP-OES, both external calibration and standard addition yielded comparable Am amount concentrations. Calibration of the SF-ICP-MS response for Am was accomplished using both 232 Th and 238 U signals as well as applying the related mass bias. This calibration methodology that is frequently used in the absence of an Am stock standard solution was tested against a home-made 241 Am stock standard solution underlining the validity of this calibration approach. Sector field ICP-MS analysis essentially confirmed the Am concentrations obtained using ICP-OES in the three spent fuel solutions with mean values overlapping within their standard deviations. Considering isotopes of other actinides such as Pu and curium (Cm), the Am isotopic abundance (241 Am, 242 Am, 243 Am) was established in two non-separated fuel solutions comparing well with model calculations based on the ORIGEN-2 code.

Accurate analytical data reinforces fundamentally the meaningfulness of nuclear fuel performance assessments and nuclear waste characterization. Regularly lacking matrix-matched certified reference materials, quality assurance of elemental and isotopic analysis of nuclear materials remains a challenging endeavour. In this context, this review highlights various dedicated experimental approaches envisaged at the European Commission—Joint Research Centre—Institute for Transuranium Elements to overcome this limitation, mainly focussing on the use of high resolution-inductively coupled plasma-optical emission spectrometry (HR-ICP-OES) and sector field-inductively coupled plasma-mass spectrometry (SF-ICP-MS). However, also α- and γ-spectrometry are included here to help characterise extensively the investigated actinide solutions for their actual concentration, potential impurities and isotopic purity.

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