Up & Atom


The commissioners of the Nuclear Regulatory Commission (NRC) approved almost all of the staff’s proposed approach for adding a new part to its regulations, 10 CFR Part 53, to govern licensing of advanced nuclear reactors. The commissioners directed the staff to expedite finalizing the rule by October 2024—three years earlier than the staff had proposed—and to report back with any “key uncertainties” that would affect finalizing the rule by that date. The commissioners also asked the staff to report back with options regulating fusion (vs. fission) reactor designs.

To help expedite the rulemaking, the commissioners rejected the staff’s proposal to include an advanced notice of proposed rulemaking. Instead, they authorized the staff to “implement the development and intermittent release of preliminary draft rule language, followed by public outreach and dialogue, and further iteration on the language until the staff has established the rudiments of its proposed rule for Commission consideration.”

Finally, the commissioners recognized that the new regulations could provide high-level requirements, with guidance documents addressing details and technology-specific considerations. Therefore, the commissioners urged the staff to work with stakeholders to identify and develop applicable guidance and technical bases.

The commissioners’ approval responds to the staff’s April 13, 2020 rulemaking plan, which proposed a schedule resulting in the publication of the final rule in August 2027. In response to the rulemaking plan, we urged the NRC to issue the proposed rule in October 2021 and the final rule by October 2023, observing that advanced reactor applications were already being submitted to the NRC and that interested parties were well positioned to comment on and work with the NRC regarding the development of the rule. In directing the staff to publish the final rule by October 2024, the commissioners accelerated the staff’s proposed schedule by nearly three years.

A new rulemaking is required for advanced reactors because the current licensing requirements under 10 CFR Parts 50 and 52 only cover light-water reactors and nonpower reactors, and do not contemplate unique aspects of advanced nuclear reactor designs. The scope of the rulemaking would “focus on risk-informed functional requirements building on existing NRC requirements, Commission policy statements, and recent activities undertaken to implement the NRC’s vision and strategy for non-light-water reactors.”

In addition to requirements appropriate for non-light-water reactor technologies and inherently recognizing the technological advancements of those designs, the rulemaking would

  • promote regulatory stability, predictability, and clarity;
  • reduce requests for exemptions from the current requirements in 10 CFR Parts 50 and 52; and
  • credit the response of advanced nuclear reactors to postulated accidents, including slower transient response times and relatively small and slow-release fission products.

Authors Alex Polonsky and Jane Accomando are members of the Nuclear Energy Institute’s Part 53 Task Force, and Morgan Lewis will continue to closely follow the NRC’s developing plans to license advanced reactor designs.