Abstract and subjects
Neutron imaging and tomographic reconstructions provide non-destructive three-dimensional characterization of nuclear fuel pellets that are typically about a cubic centimeter in volume with energy-resolved neutron imaging at a pulsed neutron source offering unique characterization not possible at a reactor source. Recent measurements at the Los Alamos Neutrons Science Center (LANSCE) studied a series of uranium nitride / uranium silicide ceramic composite pellets. This paper provides examples of spatially resolved measurements of cracks, isotopic enrichment and density with a (current) spatial resolution of approximately 75 microns. Phase and texture measurements were also performed but are not discussed in this paper. The UN/U-Si systems are under consideration as candidate systems for accident tolerant fuel. The examples are taken from measurements on a total of 9 pellets of differing UN/U-Si formulations (2 enrichment levels), U{sub 3}Si{sub 5} reference formulations (two enrichment levels) and pellets with known flaws. The {sup 235}U enrichments ranged from 0.2 to 8.8 wt.%. Pellets of the same composition are scheduled for irradiation in the Advanced Test Reactor this year. (authors)