The ability to examine elemental and isotopic ratios of fuels, waste forms, and other solids by direct analysis using laser ablation techniques can greatly reduce analysis costs and time while reducing worker dose. Applying this method to the actinide elements is especially relevant, as these isotopes contain useful information related to nuclear fuel behavior, material origin, and waste form properties. Current methods to evaluate the composition of used fuel include a lengthy process of digestion, separations and often require multiple techniques and sample preparations to determine the elemental and isotopic composition. These techniques also remove all spatial information during the analysis, preventing the collection potentially useful data for detailed analysis. The goal of this effort is to develop and optimize laser ablation inductively coupled mass spectrometry (LA-ICP-MS) for applications to the analysis of fuel, used fuel, and waste forms. This work focuses on uranium oxide simulated used nuclear fuels starting with binary systems of (U,Pu)O2, (U,Np)O2, (U,Ce)O2 and (U,Zr)O2. Methodology was successful in observing linearity of 0.995 and greater for these systems. This result was achieved by minimizing the particle size distribution of the aerosol and in turn decreases the time-dependent fractionation often observed in LA-ICP-MS. Actinide matrices and standards were prepared and characterized by physical, thermodynamic, and chemical analysis. The limit of detection, accuracy, and precision of LA-ICP-MS was evaluated using the oxide material. The ablation zone on the material was assessed for physical and chemical changes to determine impact of ablation. The ablation behavior of the elements tested was correlated with physical and thermodynamic properties of the materials. The heat capacity of the materials was measured to determine trends with thermodynamic properties of the desired elements. The limit of detection for 239Pu in a UO2 matrix was determined to be 0.026 wt. %. The LA-ICP-MS is an excellent technique for determining 239Pu in a UO2 matrix that will determine burnup rates well below 13 MWd kg-1 HM. This technique could be applied to fresh or used fuel to quantify plutonium and neptunium for safeguards, nuclear forensics, and the nuclear fuel cycle.

Evaluation of mixed actinide oxides by laser ablation ICP-MS

253rd National Meeting (2017)

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