Why It Matters

The House Science, Space, and Technology Subcommittee on Energy held a hearing September 2 on advanced nuclear reactors, examining efforts to accelerate deployment, strengthen the domestic nuclear fuel supply chain and compete with China and Russia.

The hearing, titled "Powering the Nuclear Renaissance: Accelerating U.S. Leadership in Advanced Nuclear Reactors," brought together reactor developers, a national laboratory official and an academic expert to examine progress toward commercial deployment and remaining regulatory, fuel-supply and workforce challenges. President Donald Trump (R) signed four nuclear-energy executive orders in May 2025 directing federal agencies to accelerate reactor testing, deployment and fuel-cycle development.

Advanced nuclear technologies could provide round-the-clock electricity for data centers, military installations and the electric grid while supplying industrial heat for manufacturing and other applications. But developers still face significant barriers involving nuclear fuel availability, licensing, supply chains, financing and the transition from demonstration reactors to commercial deployment.

The hearing came after several private reactor developers reached major testing milestones. Antares Nuclear achieved zero-power criticality on June 4, Valar Atomics followed on June 18, and Aalo Atomics reached criticality on July 4. A separate Deployable Energy reactor became the third DOE-authorized reactor to reach criticality before the July 4 target, meaning four reactors ultimately met the broader administration milestone. 

Aalo said its Aalo-X Critical Test Reactor reached criticality at 12:20 a.m. Mountain Time on July 4 at Idaho National Laboratory. The company described the reactor as a full-scale, zero-power demonstration of the core technology planned for its future 10-megawatt electric reactors.

The Big Picture

Nuclear power supplies about 20 percent of U.S. electricity generation. As of March, the United States had 94 operating commercial nuclear reactors at 54 nuclear power plants in 28 states, according to the Energy Information Administration. 

Congress has supported advanced nuclear development through legislation including the Energy Act of 2020, which expanded federal research, demonstration and commercialization programs for advanced reactors and nuclear fuels.

In January, the Department of Energy awarded $2.7 billion in task orders to strengthen domestic uranium enrichment. The awards included $900 million each for American Centrifuge Operating, General Matter and Orano Federal Services to expand domestic low-enriched uranium and high-assay low-enriched uranium capacity over the next decade. 

In late July, DOE selected Utah, Tennessee, Oklahoma, Louisiana and Idaho as potential hosts for Nuclear Lifecycle Innovation Campuses. The department signed memorandums of understanding with the states to explore sites that could colocate activities including uranium enrichment, fuel fabrication, used-fuel reprocessing, waste disposition, advanced reactors and manufacturing. No final hosting decisions have been made. 

China and Russia remain major competitors in global nuclear development and exports. Lawmakers and witnesses discussed how state-backed financing and overseas reactor construction give foreign suppliers advantages when competing for international nuclear projects.

Regulatory reform has also advanced. NRC Part 53 became effective April 29 and provides an additional risk-informed, performance-based and technology-inclusive licensing framework for commercial advanced reactors. It operates as an alternative to existing licensing pathways rather than replacing them.

What They're Saying

Rep. Randy Weber (R-TX), chair of the Energy Subcommittee, framed the hearing around accelerating advanced reactor deployment and maintaining U.S. technological leadership.

Rep. Deborah Ross (D-NC), the ranking member, supported continued development of advanced nuclear energy while emphasizing cost control, safety, regulatory independence and federal investment in demonstration projects and workforce development. Ross noted that Antares had recently been selected by the Army to construct a microreactor at Fort Bragg in North Carolina. 

Five witnesses testified: Joe Hoagland, associate laboratory director for Fusion and Fission Energy Science at Oak Ridge National Laboratory; Isaiah Taylor, CEO and founder of Valar Atomics; Matt Loszak, CEO of Aalo Atomics; Steven Shannon, head of the Department of Nuclear Engineering at North Carolina State University; and Jordan Bramble, CEO and co-founder of Antares Nuclear. 

Hoagland discussed the national laboratory system's role in reactor testing, fuel development and commercialization. Taylor described Valar's reactor development work and the company's progress under DOE's Reactor Pilot Program.

Loszak discussed Aalo's modular reactor design and the company's plan to use 10-megawatt electric reactors in 50-megawatt Aalo Pods aimed initially at data centers. Aalo says it is developing a second reactor intended to generate electricity in 2027. 

Shannon focused on the nuclear workforce and the role of universities in training engineers and other specialized workers needed to support an expanded nuclear industry.

Bramble discussed Antares' Mark-0 demonstration reactor and the company's work with the military. Antares reached criticality at Idaho National Laboratory in June and has been selected to provide a microreactor for Fort Bragg under the Army's Janus Program.

Political Stakes

The hearing demonstrated bipartisan interest in advanced nuclear energy but also differences over the federal government's role in deployment and oversight.

Republicans emphasized faster testing, licensing and deployment, while Democratic members stressed that acceleration should not come at the expense of safety, independent regulation or protections against customers bearing the costs of unsuccessful first-of-a-kind projects. Ross said federal agencies and national laboratories can help bridge the gap between early-stage technologies and commercial deployment while maintaining sufficient expert staffing. 

The Army's Janus Program also illustrates the national security dimension. The program is intended to deploy commercially owned and operated microreactors at military installations, with an executive-order target of having at least one Army-regulated reactor operating at a domestic installation by September 30, 2028.

Support for advanced nuclear development does not eliminate concerns about cost, regulation and safety. Ross warned that first-of-a-kind reactor projects can carry significant financial risk and argued that electricity customers should not be forced to absorb cost overruns.

Democratic members also emphasized the importance of maintaining an independent Nuclear Regulatory Commission and sufficient federal technical expertise as agencies attempt to accelerate licensing and deployment. 

The Bottom Line

Congress is considering several bills aimed at expanding nuclear deployment and exports.

The ACE Nuclear Energy Act, S. 4228, introduced by Sens. Dave McCormick (R-PA) and Andy Kim (D-NJ), would change how the Export-Import Bank calculates its statutory default rate for civil nuclear financing and expand its ability to offer market-competitive compensation to certain employees. Supporters argue the changes would make it easier for the bank to finance U.S. nuclear exports. The bill remains before the Senate Banking Committee. 

The Nuclear Energy Innovation and Deployment Act, S. 4284, introduced by Sens. Mike Lee (R-UT) and McCormick, would clarify and modernize DOE authorities for nuclear facilities and materials and establish mechanisms intended to help advanced technologies move from demonstration to wider commercial deployment. The bill remains before the Senate Energy and Natural Resources Committee.

The hearing highlighted rapid progress in advanced reactor testing and bipartisan interest in expanding nuclear energy, but lawmakers and witnesses also identified unresolved challenges involving fuel supply, commercialization, workforce capacity, regulation and project costs. The debate is increasingly focused not only on whether advanced reactors can work, but on how quickly they can move from federally supported demonstrations to reliable commercial and military deployment.

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