Nuclear Power Gets a Size Upgrade: New Bill Redefines 'Small' Reactor for Federal Funding and Regulation

If you’ve heard the buzz about Small Modular Reactors (SMRs) being the future of nuclear power, this bill is the government giving that future a serious push. The Small Modular Reactor Commercialization Act of 2025 is essentially a regulatory and financial tune-up designed to accelerate how quickly these next-generation reactors can be built and plugged into the grid.

The New Definition of “Small”

The biggest change here is a simple number swap that has major implications for developers. Previously, for many federal programs and definitions, a reactor had to be 300 electrical megawatts (MW) or less to count as “small modular.” This bill hikes that limit significantly, redefining an SMR as any advanced nuclear reactor with a rated capacity of less than 500 electrical megawatts (Sec. 3, Sec. 7). Think of it like the government increasing the size limit for carry-on luggage—suddenly, you can bring a much bigger suitcase. For developers, this means slightly larger, more powerful reactor designs can now qualify for the same federal funding and regulatory pathways previously reserved for smaller models.

This size increase isn't just theoretical. It directly impacts funding: the Department of Energy (DOE) is now explicitly told they cannot deny financial assistance for SMR development or deployment just because a single reactor unit is rated between 50 MW and 500 MW (Sec. 5). This opens the door for bigger projects to get federal help, which is crucial because nuclear plants require massive upfront investment. For the average person, this means that if SMRs are deployed, they will be slightly larger and potentially more efficient than originally planned under the old rules.

Clearing Regulatory Hurdles

The bill also tidies up some old rules that were getting in the way. It increases the capacity limits under the Atomic Energy Act of 1954 for modular reactors. The individual unit capacity limit jumps from 300,000 electrical kilowatts to 500,000 electrical kilowatts, and the total combined capacity limit at a single site moves from 1.3 million to 1.5 million electrical kilowatts (Sec. 2). This is a technical fix, but it’s essential: it ensures that the regulatory ceiling matches the new, larger size definitions, preventing developers from hitting arbitrary legal roadblocks after they’ve invested millions in a new design. To make sure everyone’s on the same page, the Nuclear Regulatory Commission (NRC) and the DOE are mandated to update all their existing guidance documents to align with these new 500 MW definitions (Sec. 4).

Commercialization: Making Nuclear a U.S. Industry

Perhaps the most forward-looking part of the bill is the creation of the Small Modular Reactor Commercialization and Industrialization Competitiveness Working Group (Sec. 6). This group, led by the Secretary of Energy and including representatives from Defense, State, Commerce, and Treasury, is tasked with figuring out how to make the U.S. the global leader in building and selling SMRs. They’re looking at everything from bringing long-term manufacturing investments here to preparing the workforce for large-scale SMR deployment. This is the government saying, “We don’t just want to use this technology; we want to build it here.” The goal is clearly to capture the economic benefits of this emerging energy sector, which could mean specialized manufacturing jobs and a more robust energy supply chain in the U.S.

While the bill is mostly about regulatory fine-tuning and boosting industry, the impact is clear: it’s designed to speed up the transition to advanced nuclear power. For those worried about grid stability or energy costs, this bill removes some of the bureaucratic friction that slows down the deployment of new power sources. The main focus is on making the technology economically viable and industrially competitive, ensuring that if SMRs are indeed the future, the U.S. is ready to build them.