ARPA-E HORNIG (Gen IV reactors)
Funds United States nuclear ventures for Gen IV reactor research and advanced reactor design.
ARPA-E HORNIG (Gen IV reactors) sits under the Advanced Research Projects Agency – Energy and focuses on advanced nuclear isotopes for next-generation reactors. It is an active U.S. grant route for for-profit applicants, with a rolling cycle and U.S.-only geography. Award sizes run from $500,000 to $5 million. The program is shaped for energy technology teams rather than nonprofits or individuals. It is narrower than ARPA-E OPEN because the subject matter is explicitly tied to Gen IV reactor work and the nuclear supply chain, so the strongest applicants will already know how their technology connects to reactor performance or fuel-cycle needs. With no fixed round schedule listed, the key test is fit to the technical brief rather than timing. Companies that can explain why their nuclear material or isotope work matters for next-generation systems, safety, performance, or fuel-cycle resilience will fit better than general clean-tech applicants, especially if the proposal reads like an engineering plan rather than a broad energy concept.
No upcoming rounds verified. Cadence: Rolling.