Enrichment Bottleneck

Uranium enrichment — the process of increasing U-235 concentration from the ~0.7% in natural ore to the 3-5% required by light-water reactors (or 20% HALEU for advanced reactors) — is the second major chokepoint in the nuclear fuel cycle, distinct from mining. Enrichment capacity is measured in Separative Work Units (SWUs) and is highly geographically concentrated: Russia's TENEX/Rosatom was providing ~28% of US utility enrichment before geopolitical shifts forced diversification. The post-2022 exit from Russian enrichment created both a supply gap and a peculiar phenomenon called "overfeeding."

Overfeeding and Ghost Demand

When Western enrichers are underutilized (limited by installed centrifuge capacity), they can "underfeed" — using less natural uranium per SWU to preserve enriched output. Conversely, when capacity is constrained, enrichers "overfeed" — using more natural uranium per SWU to maximize throughput from existing centrifuges. The US exit from Russian enrichment forced Urenco (Europe) and Orano (France) to overfeed, increasing their natural uranium consumption per unit of enriched product. This creates "ghost demand" — additional raw uranium needs that don't correspond to more reactors, just more natural feed per SWU. This is a structural driver of uranium spot demand that is easy to underestimate.

Key Players

HALEU

High-Assay Low-Enriched Uranium (≥5% and ≤20% U-235) is required by many advanced reactor designs (SMRs, microreactors). Centrus Energy is the only US commercial HALEU producer, operating a demonstration cascade in Piketon, Ohio. DOE's $2.7B enrichment investment includes HALEU expansion. Russia's TENEX was the only other commercial HALEU source — making this the single highest-leverage nuclear supply-chain chokepoint after the war in Ukraine began.

Key Claims

• Russia's TENEX supplied ~28% of US utility enrichment before 2022 sanctions pressure forced diversification. Evidence: strong (USITC, industry sources)
• The US Prohibit Russian Uranium Act (2024) bans Russian enriched uranium imports with waiver authority through 2028. Evidence: strong (US Congressional record)
• Overfeeding creates ghost demand: utilities using non-Russian enrichers are consuming significantly more natural uranium per SWU — a structural demand floor. Evidence: moderate (Uranium Unleashed, 2026)
• Centrus is the sole US HALEU producer — its single cascade can produce ~900,000 SWU/yr; DOE's investment targets expansion. Evidence: strong (DOE, 2025)
• DOE committed $2.7B over a decade to domestic enrichment expansion. Evidence: strong (DOE, 2025)

Open Questions

• When will Urenco USA (Eunice, NM) complete capacity expansion, and by how much does it reduce the overfeeding premium?
• Can Centrus scale HALEU to commercial quantities (millions of SWU/yr) within the decade?
• Will Congress extend the Russian uranium import waiver beyond 2028 if Western enrichment is still insufficient?
• What happens to the enrichment market if TerraPower (Gates-backed, Na-cooled fast reactor) and other HALEU-consuming designs scale to 10+ GW?

Related Concepts

• Uranium Supply Deficit — the upstream mining constraint; enrichment is the midstream

Changelog

• 2026-06-15 — Initial compilation from DOE releases, Uranium Unleashed, Carbon Credits, Sprott (2025-2026)