Enrichment tails assay

[Cami]

A measure of the amount of fissile uranium (U-235) remaining in the waste stream from the uranium enrichment process. The natural uranium feed that enters the enrichment process generally contains 0.711 percent (by weight) U-235. The product stream contains enriched uranium (more than 0.711 percent U-235) and the waste or tails stream contains depleted uranium (less than 0.711 percent U-235). At the historical enrichment tails assay of 0.2 percent, the waste stream would contain 0.2 percent U-235. A higher enrichment tails assay requires more uranium feed (thus permitting natural uranium stockpiles to be decreased), while increasing the output of enriched material for the same energy expenditure.