Tails Assay
Tails assay measures the uranium-235 concentration in depleted tails from enrichment plants. Lower tails assay (0.25-0.30%) improves efficiency and reduces SWU requirements.
Standard tails assay is 0.30 wt% U-235; advanced centrifuges achieve 0.15-0.25%. Affects product assay (3-5% for LWRs, 19.75% HALEU). Centrus targets 0.20% for LEU. Key metric for enrichment economics.
Why it matters now
Optimizing tails assay cuts HALEU costs amid 2025-2026 SMR fuel crunch. US DOE contracts prioritize low-assay tech for domestic supply security.