Antares CEO Jordan Bramble on securing the first DOE safety approval for a new US nuclear reactor design in decades
Key Points
- Antares received final DOE safety approval for a heat-pipe-cooled nuclear reactor, the first new reactor design authorized under current US standards in decades.
- The company targets neutron criticality testing in 2026 and electricity production in 2027, with primary markets in defense and space propulsion.
- Bramble credits a bipartisan political realignment around energy sovereignty and reindustrialization, plus AI data center demand, for making nuclear economically viable again.
Summary
Antares secures first DOE safety approval for a new US reactor design in decades
Jordan Bramble, CEO and co-founder of Antares, says the company has received its final regulatory approval from the Department of Energy — a Documented Safety Analysis (DSA) — for a heat-pipe-cooled, graphite-moderated nuclear reactor. It is the first time a new reactor design has been authorized under DOE standards in the US. The previous time a new-design reactor was built at a DOE site, the regulatory pathway being used today didn't yet exist.
The reactor uses TRISO fuel — uranium particles encapsulated in silicon carbide, pressed into graphite compacts — and is cooled by heat pipes that vaporize sodium to move heat passively, with no pumps required. The entire system, including the power conversion unit, fits on a truck bed.
“This is actually the first time for the country that a reactor, a new reactor, has been authorized under DOE standards. The last time a new reactor was built at a DOE site of a new design, was before this regulatory pathway actually existed... Full thermal power in 2025, we're gonna be making neutrons this year in 2026, and then electrons in 2027 with an electricity producing reactor.”
Development timeline
Antares has been at this for three years. The sequence so far:
- 2024–2025: Invested several million dollars building out its test facility, RACE (Reactors and Critical Experiments Facility), at Idaho National Lab — the same building where the US Army tested the ML-1 reactor in 1967
- 2025: Tested an electrically heated prototype at full thermal power
- 2026: Targeting neutron criticality, which will validate control system performance and confirm nuclear simulation data
- 2027: First electricity-producing reactor, with the goal of reaching a customer site with a paying customer
Bramble says the criticality test is also serving a practical function beyond validation — debugging supplier lead times and supply chain performance, and establishing a replicable regulatory template for future reactors.
Market focus
The primary market is defense. Bramble argues that US military installations increasingly depend on the commercial grid and civilian diesel supply chains to power assets that generate war-fighting effects — and that adversaries are now capable of disrupting both. Modular nuclear plants running in parallel banks, he says, offer uptime and supply-chain resilience that no alternative energy source can match.
The second near-term market is space. NASA administrator Jared Isaacman announced two weeks ago that NASA wants to fly a nuclear-powered spacecraft to the moon by December 2028. Bramble's focus there is nuclear electric propulsion — using a reactor to generate electricity that powers ion thrusters — rather than nuclear thermal propulsion. The power-density advantage over solar is most acute beyond one astronomical unit, but he argues it becomes relevant in Earth orbit too: a 100-kilowatt solar array in space would be roughly the size of a football field; a nuclear-powered equivalent could fit on a Falcon 9.
Commercial applications, including remote industrial sites where diesel generators are the current default, are a longer-term target.
Why now
Bramble traces the nuclear revival to a confluence of factors: executive orders signed earlier in the current administration creating a streamlined regulatory pathway, bipartisan political alignment on reindustrialization and energy sovereignty, and a structural energy bottleneck driven by AI data center buildout and domestic manufacturing ambitions. He also points to what didn't happen in the US — unlike France, which treated nuclear as a matter of energy sovereignty and went all-in during the same period, the US cut R&D funding during the austerity era and never built a true nuclear private sector before cheap natural gas from fracking made large-scale nuclear economically unattractive.
Bramble says nuclear is now a bipartisan issue to a degree he finds striking. He spends three to four days a month on Capitol Hill, and says it has become difficult to tell Democrats from Republicans when discussing it — reindustrialization, clean energy, national security, and American jobs all point in the same direction.