Most SMR designs need a fuel that barely exists
Here are two numbers that belong next to each other.
A single small modular reactor’s first core needs several tonnes of high-assay low-enriched uranium. Western production of that material, in the year to mid-2026, was about 900 kilograms — from one demonstration cascade at Piketon, Ohio.
That is the SMR fuel problem in its entirety.
What HALEU is
Uranium enriched above 5% and below 20% U-235. The lower bound is where conventional reactor fuel stops; the upper bound is where uranium becomes legally “highly enriched” and attracts an entirely different security and safeguards regime. HALEU sits deliberately just underneath that line.
Higher enrichment lets a reactor run longer between refuellings, hold a smaller core, and use fuel forms conventional enrichment cannot support. That is why so many advanced designs specify it: TRISO-fuelled high-temperature reactors, sodium-cooled fast reactors, most molten salt concepts.
Who can make it
Until October 2023, in the West: nobody.
Russia’s Tenex was the only established commercial supplier in the world. The 2024 US import ban closed that route. What exists in its place:
- Centrus at Piketon — a demonstration cascade producing roughly 900 kg a year. In 2026 it received a $900 million DOE task order to expand to commercial scale.
- Downblending surplus weapons-grade uranium at Savannah River — about 3.1 tonnes total. A finite stock, not a supply chain.
- Urenco at Capenhurst — targeting 2031.
- Orano’s Project IKE at Oak Ridge — in development.
- X-energy’s TRISO-X plant, which turns HALEU into finished pebbles — targeted for the first half of 2028.
Why this should change how you read announcements
Of the seventeen designs on our SMR tracker, ten need HALEU — including three of the seven that already hold a construction permit or better. TerraPower’s Natrium schedule has already slipped once for exactly this reason: the design assumed Russian supply.
Set the fuel dates against the reactor dates. Developers promise units in the late 2020s. The facilities meant to fuel them are dated 2028 to 2031.
A reactor can be licensed, financed and built, and still have nothing to run on. When you read an SMR announcement, the question that separates a project from a press release is not “has it been approved” but “where is the fuel coming from, and when”.