Vibratory Compaction of Uranium Dioxide, (I)

Abstract

As part of research 011 the vibratory compaction method of fabricating U0₂ fuel elements, the effect of vibration character (frequency, acceleration and so on) on the compaction density was studied with sinusoidal wave vibration generated by an electrodynamic-shaker, with the view to optimization of vibration conditions for obtaining high compaction densities. Fused UO₂ with a particle size distribution of −6, +12 mesh: 67.5w/o, −40, +70 mesh: 20.0w/o, −200 mesh: 12.5w/o (mesh: US. Unit) was compacted into 40 “long, 0.5” outer diameter and 0.035 wall 304 stainless steel tubes. Optimum results (88% of theoretical density) were obtained with the following stepwise acceleration increase procedure:

1.	Powder blend is poured into the tube while it is vibrating at 8 G's and 300 cps.
2.	After the tube is filled, acceleration is increased to 20 G's at the same frequency of 300 cps and vibration is maintained for 2 min.
3.	Then, acceleration is increased to 40 G's and sweeping of frequencies between 300 and 3,000 cps is initiated at the rapid speed of 4.4 decades/min, while maintaining a constraining load of 4 kg on the powder.
4.	After 2 min vibration at 40 G's, acceleration is increased to 60 G's and sweeping vibration is kept for 10~15 min.