The Nuclear Regulatory Commission has issued a new licensing pathway that accelerates safe, innovative reactor deployment and reinforces U.S. energy leadership, marking the first new reactor licensing framework in decades. The rule, known as Part 53, is designed to provide optionality and make licensing advanced nuclear reactors faster, simpler, and more cost-effective while continuing to prioritize safety.

Part 53 introduces technology-inclusive safety standards, increased flexibility for reactor design and operation based on risk analyses, graded security requirements, and innovative features to accelerate reactor deployment. The improvements are expected to reduce unnecessary duplication in reviews, allow developers to complete licensing in stages, establish clearer, more predictable pathways to approval, and could significantly reduce the time and cost required to bring new reactors online.

"This final rule is a major NRC action that provides a clear risk-informed, technology- inclusive licensing framework to enable new nuclear to safely move faster from concept to construction," NRC Chairman Ho K. Nieh said. "It is another example of how the NRC is delivering on its mission by keeping safety at the forefront while aligning to the evolving nuclear energy landscape."

The Commission directed the staff to finalize the rule and supporting guidance, which can be used for any type of reactor. Part 53 fills a long-standing gap: existing regulations in Part 50 were built around light-water reactor technology, while many new designs use different approaches. Under Part 53, applicants will no longer need to seek exemptions from light water reactor based requirements.

Part 53 is part of a broader national effort to modernize how the United States regulates nuclear energy, supported by laws like the Nuclear Energy Innovation and Modernization Act of 2019. The NRC completed Part 53 almost two years ahead of the deadline required by NEIMA. The new framework sets the stage for several upcoming rules in the next few months under Executive Order 14300, which will revolutionize reactor licensing.

This is the first new set of regulations to address initial reactor licensing since 1989, when the NRC created Part 52, and the first major update to reactor licensing standards since 1956, when the Atomic Energy Commission issued Part 50.

The U.S. Nuclear Regulatory Commission was created as an expert, technical agency to protect public health, safety, and security, and regulate the civilian use of nuclear materials, including enabling the deployment of nuclear power for the benefit of society. Among other responsibilities, the agency issues licenses, conducts inspections, initiates and enforces regulations, and plans for incident response. The NRC is collaborating with interagency partners to implement reforms outlined in new Executive Orders and the ADVANCE Act to streamline agency activities and enhance efficiency.

Part 53 offers a comprehensive new approach to license advanced reactors, including non-light-water reactors, across their life cycles. It provides designers and operators with more flexibility in how they build and run their plants while continuing to ensure safety. The rule builds on years of research and collaboration with the Department of Energy, industry, and the public, including extensive public meetings and comments on the proposed rule published Oct. 31, 2024.

Part 53 will take effect 30 days after it appears in the Federal Register in the coming weeks. The NRC is also publishing nine guidance documents, with additional guidance to follow.

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