ARPA-E's HORNIG programme is the US government's attempt to answer a question that has stalled advanced reactors for years: if you can recover plutonium and minor actinides from used fuel, can you actually make a qualified fuel out of them — quickly enough to matter?
On 29 October 2026, the agency selected eight projects to share up to $50 million. The combined announced awards total roughly $44.9 million. The programme name expands to High-performance Optimized Recycled Nuclear Isotopes for Gen IV reactors and is funded under opportunity DE-FOA-0003623.
This is a research and development programme. No reactor, fuel plant or major equipment package has been ordered under it, and the projects are at feasibility/early-R&D stage. Firms looking for construction or steel supply opportunities will find none here yet; the value lies in which fuel technologies and supply chains get a head start.
What HORNIG is actually trying to do
HORNIG funds design, fabrication, irradiation testing, modelling and qualification of fuels containing transuranic (TRU) elements — plutonium and the minor actinides — recovered from the existing US inventory of used nuclear fuel. The explicit target is to compress fuel qualification from the decades historically required to less than seven years.
It follows CURIE (Converting UNF Radioisotopes Into Energy), launched in 2022, which focused on recovering TRU material. HORNIG's premise is that CURIE-style separation is only useful if there is a fuel to put the material into. Notably, only one HORNIG awardee — Idaho National Laboratory — also held a CURIE project, which suggests the programme is deliberately broadening its industrial base rather than extending existing teams.
The American Nuclear Society reports that ARPA-E frames HORNIG as advancing Executive Order 14302, "Reinvigorating the Nuclear Industrial Base". That policy linkage matters: it signals that recycled-TRU fuel is being treated as a strategic domestic fuel-cycle capability, not merely an academic materials question.
The eight projects
The selections span almost every advanced fuel form now under development in the US — a deliberate portfolio approach rather than a bet on one reactor type.
| Lead organisation | Project | Fuel concept | Award (USD) |
|---|---|---|---|
| Westinghouse Electric Company | PowerBlock: Additively Manufactured Metallic Fuel | Metallic fuel made by laser powder-bed fusion, for current fleet and advanced reactors | 7,000,000 |
| Oregon State University | TRU-Nitride Fuel for Advanced Reactors | TRU-bearing nitride fuel via low-temperature fabrication | 7,000,000 |
| Idaho National Laboratory | IMPACT | Chloride salt containing recycled TRU for molten-salt reactors | 7,000,000 |
| Standard Nuclear | Mixed Oxycarbide (MCO) TRISO | TRISO incorporating recycled TRU and uranium for high-temperature gas reactors | 6,999,984 |
| Oklo Inc | FORGE | U-TRU-Zr metallic fuel for sodium-cooled reactors, from electrorefiner product | 6,842,989 |
| Texas A&M University | TB²-MSR | Thorium-based liquid fuel salt incorporating TRU for molten-salt reactors | 5,377,799 |
| Sandia National Laboratories | TRU fuel pathways analysis | Sociotechnical, technoeconomic and harmonisation analysis | 3,381,128 |
| Exodys Energy | Integrated TRU Fuel Cycle Analytics | Feedstock, fuel-cycle cost, transport and deployment framework | 1,300,792 |
Source: ARPA-E project descriptions as reported by ANS. Award figures are as announced; final obligated values under cooperative agreements may differ.
Three features of this list stand out.
Metallic fuel dominates the industrial awards. Westinghouse and Oklo together account for nearly $14 million, and both are working on metal fuel — though by very different routes. Westinghouse's PowerBlock uses additive manufacturing (laser powder-bed fusion) plus computational modelling, targeting 24-month fuel cycles and thermal power above 4,200 MWt. Oklo's FORGE starts from electrorefiner product, tying fuel fabrication directly to pyroprocessing of used fuel.
TRISO gets a recycled-TRU variant. Standard Nuclear's MCO TRISO project, with SHINE Technologies as partner, is positioned explicitly as an alternative to HALEU for high-temperature gas reactors. That framing is commercially significant: it offers gas-reactor developers a fuel route that does not depend on the constrained HALEU supply chain.
Two awards fund the analysis layer. Sandia and Exodys are not making fuel. They are building the technoeconomic, feedstock, transport and decision-support frameworks that would let the other six concepts be compared and scaled. This is often the least visible but most transferable output of a portfolio programme.
Who the awardees are — and why it matters
The participant mix is unusually commercial for an ARPA-E fuels programme.
- Westinghouse supplies roughly 40% of the global reactor fleet, but none of that fleet runs on metallic fuel. It fabricates at Västerås (Sweden), Springfields (UK) and Columbia, South Carolina, where it is separately planning a large LEU+ fuel plant. PowerBlock is therefore a new product line for an incumbent supplier, not an incremental tweak.
- Standard Nuclear (NYSE: STDN) is a 2024 startup that acquired the assets of bankrupt Ultra Safe Nuclear. It is the only independent US TRISO manufacturer, has been fast-tracked under DOE's Fuel Line Pilot Program, holds a HALEU allocation, and was selected in June 2026 into advanced negotiations under DOE's Surplus Plutonium Utilization Program. Its Tennessee and Idaho TRISO plants are reported substantially complete, with authorisation to operate targeted for Q4 2026.
- Oklo brings a downstream demand signal: its planned Advanced Fuel Center at Oak Ridge, Tennessee — a roughly $1.68 billion project announced in September 2025 — is intended to include the first privately funded US nuclear fuel recycling facility. HORNIG funding for FORGE sits upstream of that facility's fuel-manufacturing ambitions.
- Exodys Energy, founded in 2023, is one of five companies under consideration to receive DOE plutonium, giving its analytics work a direct stake in the feedstock question.
The overlap between HORNIG awardees and DOE's plutonium-disposition and HALEU programmes is the most commercially interesting pattern here. Several winners are already embedded in parallel DOE fuel initiatives, which increases the likelihood that HORNIG concepts feed into real facilities rather than ending as reports.
What this means for the steel and heavy-manufacturing supply chain
Very little, for now — and it is worth being direct about that.
HORNIG is a fuel-technology R&D programme. Its deliverables are experimental fuel forms, irradiation data and qualification cases, not fabricated pressure vessels, containment structures or bulk steel. No EPC contractor has been identified, no construction package is open, and the assessment accompanying this project correctly finds steel procurement not applicable at this stage.
Where steel could eventually matter is several steps removed: if a concept such as Oklo's FORGE or Westinghouse's additive-manufacturing route scales into a commercial fuel fabrication plant, that plant would need hot-cell structures, shielding, gloveboxes, process vessels and specialty alloys — often stainless and nickel-based rather than structural steel. Those are speculative, unevidenced future requirements and should not be treated as a pipeline.
The nearer-term industrial signal is different: additive manufacturing of nuclear fuel is a manufacturing-capability play, and Westinghouse's use of laser powder-bed fusion points toward a future where fuel fabrication capacity is measured in printers and powder supply chains as much as in sintering furnaces.
The real test: qualification speed
HORNIG's stated goal of qualifying TRU fuels in under seven years is the programme's most consequential and most difficult commitment. Fuel qualification is where advanced reactor timelines usually die — it requires irradiation campaigns, post-irradiation examination capacity, regulatory acceptance and, for TRU-bearing fuels, safeguards and materials accountancy arrangements that the ARPA-E programme documentation explicitly addresses.
The awardees will need to show progress on cooperative agreements, fabrication and testing campaigns, and eventually qualification submissions. Whether any of the eight concepts proceeds to a pilot-scale fuel fabrication facility — and on what timeline — is not yet defined in available evidence.
For industry observers, the practical takeaway is to watch two things: which HORNIG concepts attract follow-on DOE or private capital, and whether the programme's sub-seven-year qualification target survives contact with irradiation testing schedules. The answers will shape which advanced reactor developers have a domestic fuel supply — and which are still waiting for one.
