Subcritical Systems Charts New Path for Safer Nuclear Energy in US

AUSTIN, Texas – January 12, 2026 – In a move that could reshape the deployment of advanced nuclear power in the United States, Austin-based startup Subcritical Systems Inc. announced today a novel strategy to license its accelerator-driven energy system under existing federal regulations. This approach, developed after extensive dialogue with the U.S. Nuclear Regulatory Commission (NRC), aims to sidestep the lengthy and costly process of creating new rules, potentially accelerating the arrival of a new class of what the company calls “inherently safe” nuclear technology.

The announcement signals a significant milestone for the year-old company and the broader advanced energy sector, which is racing to meet surging demand for carbon-free power from data centers, heavy industry, and a grid grappling with the intermittency of renewables. By carving out a pathway within the NRC’s established framework, Subcritical Systems may have found a way to crack a regulatory code that has long challenged nuclear innovators.

A New Blueprint for Nuclear Regulation?

At the heart of the company's strategy is a plan to license its technology under two separate but existing NRC regulations. The particle accelerator, which acts as the system's ignition switch, would be regulated under 10 CFR Part 30, a framework governing accelerator-produced radioactive materials. The core of the system, a subcritical assembly of nuclear material, would be licensed under 10 CFR Part 70, which covers the domestic licensing of special nuclear material, typically for facilities like fuel fabrication plants.

This division is key. By separating the components, the company avoids the more complex and time-consuming Part 50 or Part 52 licensing processes, which are designed for traditional, self-sustaining critical nuclear reactors. The strategy suggests that because the system is not a conventional “reactor” in the critical sense, it does not need to be licensed as one. This interpretation, seemingly supported by recent NRC engagement, represents a significant strategic victory.

“Engaging with the NRC early has been an important step in establishing a clear and responsible regulatory pathway for this technology,” said Stuart Henderson, PhD, Chief Technical Officer of Subcritical Systems. Henderson, a former Director of the U.S. Department of Energy’s Thomas Jefferson National Accelerator Facility, added, “The existing Part 70 and Part 30 framework provides a viable structure for licensing accelerator-driven subcritical systems without the need for new rulemaking, while maintaining the NRC’s rigorous safety standards.”

The company’s regulatory confidence is backed by formidable legal and technical expertise. Subcritical Systems has been working with the law firm Pillsbury Winthrop Shaw Pittman LLP, a team that includes former NRC Commissioner Jeff Merrifield and nuclear engineer-turned-lawyer Anne Leidich. Their deep experience in NRC policy and advanced reactor licensing lends significant credibility to the viability of this regulatory path, which could set a precedent for other novel nuclear designs.

Beyond Meltdown: The Physics of Inherent Safety

The technology at the center of this announcement, the Energy Amplifier, is based on a concept known as an Accelerator-Driven Subcritical System (ADS). Unlike conventional reactors that must maintain a precarious, self-sustaining chain reaction (a state known as “criticality”), an ADS is designed to always remain “deeply subcritical.”

In this state, the nuclear material in the core cannot sustain a chain reaction on its own. Instead, it relies on a constant, external source of neutrons to drive the fission process and generate heat. This is where the particle accelerator comes in. The accelerator fires a beam of high-energy protons at a heavy metal target, like lead, creating a shower of neutrons through a process called spallation. These neutrons then flood the subcritical core, inducing fission and releasing energy.

The safety implications of this design are profound. The fission process is entirely dependent on the accelerator beam. If the accelerator is switched off, the external neutron source vanishes, and the chain reaction stops almost instantaneously. This design principle fundamentally eliminates the possibility of a runaway criticality accident, the central fear associated with traditional nuclear power. Furthermore, the company states its design incorporates passive decay heat removal, using natural forces like convection to cool the system after shutdown, avoiding reliance on external power and active pumping systems that proved to be a vulnerability in past nuclear accidents.

Beyond safety, ADS technology offers the potential to address nuclear energy's other long-standing challenge: waste. These systems can theoretically be fueled by a variety of materials, including existing stockpiles of nuclear waste, transmuting long-lived radioactive elements into shorter-lived ones. This could dramatically reduce the volume and long-term radiotoxicity of high-level waste, potentially shortening its required isolation from hundreds of thousands of years to a few centuries.

A Crowded Field with a Rising Tide

Subcritical Systems, incorporated in early 2025, enters a dynamic and increasingly competitive advanced nuclear market. It joins a roster of innovative companies like Bill Gates-backed TerraPower, which is building its Natrium sodium-fast reactor in Wyoming, and Oklo, which is developing compact fast reactors for data centers. Other players like X-energy are advancing high-temperature gas-cooled reactors.

These companies are all vying for a piece of a market seeing unprecedented demand. The explosion in artificial intelligence and the corresponding growth of power-hungry data centers have tech giants like Meta, Google, and Amazon actively seeking gigawatt-scale, reliable, carbon-free power. Advanced nuclear reactors are increasingly seen as the ideal solution.

In this crowded field, Subcritical Systems' value proposition appears twofold. First is its differentiated safety case, which directly confronts public apprehension about nuclear power. Second, and perhaps more crucially, is its clever regulatory strategy. If the company can successfully navigate the NRC licensing process more quickly and predictably than its competitors, it could gain a significant first-mover advantage in deploying its Energy Amplifiers for commercial applications in advanced manufacturing and industrial innovation.

A Global Race for Subcritical Power

While Subcritical Systems aims to pioneer this technology in the United States, it is not alone in its pursuit. The concept of accelerator-driven systems is being actively developed internationally, lending credence to its technical feasibility. The most prominent example is the MYRRHA (Multi-purpose Hybrid Research Reactor for High-tech Applications) project in Belgium. This ambitious, multi-billion-euro facility, currently under construction, pairs a 600 MeV particle accelerator with a lead-bismuth cooled subcritical reactor.

The primary goal of MYRRHA is to demonstrate the feasibility of transmuting high-level nuclear waste on an industrial scale, but it will also produce medical radioisotopes and serve as a materials research facility. Its phased construction, which began in 2024, is expected to culminate in a fully operational reactor by 2038, serving as a critical pilot plant for the technology. China is also known to have a significant research and development program focused on ADS as part of its advanced nuclear energy strategy. This global race underscores the perceived potential of subcritical technology to solve some of nuclear energy's most intractable problems. By leveraging decades of U.S.-led research from national laboratories, Subcritical Systems is now poised to translate that scientific leadership into a commercial reality on American soil.