Irradiation behavior of U–Nb–Zr alloy dispersed in aluminum

Three U–Nb–Zr alloys (U–5Nb–3Zr, U–6Nb–4Zr, and U–9Nb–3Zr) were included in a screening irradiation test of low-enrichment aluminum matrix dispersion fuels. Fuel particles made from these alloys reacted readily with aluminum during fuel fabrication and post-fabrication annealing, resulting in large fuel plate thickness increases. Under irradiation, the behavior of U–5Nb–3Zr (wt%) alloy based fuel was poor at 41 at.% 235U burnup, showing indications of incipient breakaway swelling. The post-irradiation microstructural characteristics of U–6Nb–4Zr based fuel were somewhat better than those of U–5Nb–3Zr, but is marginal at 70 at.% burnup. U–Mo based fuels generally show less reaction on fabrication and better fuel performance characteristics during irradiation.