2017 | AFC ACCOMPLISHMENTS 107 for characterization of specimen containing fissionable material with large thermal neutron attenuation. The goal of the Advanced Non- destructive Fuel Examination work package is the development and application of non-destructive neutron imaging and scattering techniques to ceramic and metallic nuclear fuels. Data reported in a detailed report were collected in the LANSCE run cycle that started in September 2016 and ended in February 2017. Data analysis for the tomography data is completed and a submitted report provides an overview of the characterized samples (Figure 1).The identified features in the bulk of the double encapsulated material on these demonstration fuels illus- trates the value of this characterization for pre-irradiation examination, e.g. to reject samples with flaws, as well as to post-irradiation examination, e.g. to guide destructive characterization by preparing regions of interest identified by the techniques presented here. Key results include: • 3D characterization of cracks, flaws and isotopic distributions are determined non-destructively in complete slugs to spatial resolu- tions of at least 100 microns.The tomographic reconstruction of the data from the epi-thermal neutron energy range allowed to identify several spherical features within all slugs. One slug showed a deviation from the cylindrical geometry. • Using detailed analysis of the transmission data, using the SAMMY code and known neutron absorption cross sections for interpretation of neutron transmission data, isotope specific density maps through arbitrary slices of the reconstructed volume can be displayed.The same analysis provides partial densities for isotopes averaged over the entire sample, which are except for 238U in excellent agreement with results from other methods. • The density maps of the major isotopic constituents of the slugs, computed for slices containing the spherical features, allowed to iden- tify voids as the most likely nature of the features. • 3D characterization of isotopic distributions are possible in four slugs in three to five days with the neutron flux available at LANSCE. • Diffraction data of crystallographic phase, texture and spatially resolved measurements were collected but are of limited value as the penetration depth is low and only ~0.65 mm of material is interrogated.