NRC Sets Stage for Advanced Nuclear with New Part 53 Rule

The Nuclear Regulatory Commission (NRC) has directed its staff to publish a proposed rule and draft guidance to create Part 53, a much-awaited risk-informed and technology-inclusive licensing framework geared toward advanced technologies, including non-light-water-reactors (non-LWRs).

In a staff requirements memorandum (SRM) made public on March 4, the commission directed staff to incorporate several changes to a March 2023 draft proposal within six months of the SRM’s issuance. A final version of the proposed rule is expected by September 2024. A final rule should be issued within 12 to 18 months after the proposal’s publication, taking into account a public comment period, NRC Chair Christopher Hanson told reporters on Monday.

While the 2019 Nuclear Energy Innovation and Modernization Act (NEIMA) sets a deadline for the new framework’s rulemaking to be completed by December 2027, “I would hope [a final rule] would be still fully clear of that. I don’t expect it to go out to 2027, certainly,” Hanson said. “The commission has been wanting to get moving on this, and we had urged the staff to put in more aggressive deadlines, so I think we’re well ahead of the statutory requirement.”

Hanson noted the process will offer “a lot of other opportunities for stakeholder engagement and to provide feedback. And given the amount of interest that I think we’ve seen in this rule so far, no doubt that folks out there in the world will dive into this and share their perspectives with the staff and with the commission.”

A Marked Step Forward for Part 53

The NRC’s decision to publish a proposed rule establishing Part 53 under the NRC’s Title 10 of the Code of Federal Regulations (10 CFR) marks significant progress in its regulatory effort to deliver a new licensing process as an alternative to its existing large light water reactor (LWR) licensing approaches under 10 CFR Parts 50 and 52.

“This is the first regulatory framework developed for advanced technologies and designs that includes non-light-water reactors,” the NRC underscored on Monday.

So far, 92 of the nation’s commercially operating nuclear reactors at the nation’s 54 nuclear plants have been licensed under 10 CFR Part 50, a historical two-part process involving a construction permit and an operating license as the plant approaches completion. In the 1990s, the NRC approved a second pathway, 10 CFR Part 52, which allowed an applicant to receive a combined license for construction and operation, with optional steps such as a reactor vendor applying for approval of a reactor design or builders applying for a site permit. Vogtle 3 and 4 became the first two reactors licensed under Part 52. (For more, see POWER’s explainer here.)

Part 53, as prescribed by NEIMA, is meant to offer a “voluntary” alternative to advanced nuclear applicants under a framework that would be technology-inclusive (applicable to all reactor technologies); risk-informed (using information from risk assessments to focus safety analyses on important issues); and performance-based (to ensure plants are regulated based on how they perform and not just how they are designed).

According to Dr. Adam Stein, director for Nuclear Energy Innovation at the Breakthrough Institute, the broad stakeholder consensus is that “The Part 53 rule should be predictable, flexible, enable innovation, and, importantly, be scalable.” In addition, “Part 53 should provide an innovative approach to licensing that is technology-inclusive, risk-informed, and performance-based. It should be transformational, not iterative, of existing licensing pathways,” he wrote in a recent analysis of Part 53 major topics.

But while the NRC formally kicked off efforts to craft a proposed rule in 2020, it has grappled with differing perspectives on key topics. The commission’s SRM issued on Monday follows “extensive public engagement with 21 rounds of public review and comment on preliminary rule language,” the NRC noted.

“The staff held 24 public meetings with stakeholders as well as 16 public meetings with NRC’s independent advisory group, the Advisory Committee on Reactor Safeguards. The staff will seek feedback from the public when it issues the proposed rule and draft guidance later this year,” it said.

Significant Changes Compared to the March 2023 Draft Proposal

While the commission on Monday set redlines and ordered significant changes to its draft proposal in its SRM, the changes are a “step in the right direction,” Stein told POWER on Monday. Pivotally, they address many key concerns raised by stakeholders, he said.

The proposed rule will be based on several criteria, including “reactor siting requirements; analyzing potential accidents; defining safety functions; categorizing structures, systems, and components; addressing construction and manufacturing requirements; providing defense in depth; and protecting the public and plant workers during normal operations,” the NRC said. “The proposed rule also modifies agency regulations for operator licensing, employee fitness-for-duty, physical security, and site access authorization.”

In perhaps the most prominent change, the commission disapproved the inclusion of Framework B, a proposed framework to provide a “traditional” but technology-inclusive option that differs from the preferred Framework A by design.

The NRC had noted that because Framework B includes the “same or similar structure and requirements as 10 CFR Part 50 and 10 CFR Part 52,” it provides a basis for the NRC to make its findings “on reasonable assurance of adequate protection without the need to establish risk-informed performance standards, such as [quantitative health objectives (QHOs)].” The commission on Monday, however, directed staff to develop an options paper within one year, including an option to use a separate part in the 10 CFR for Framework B.

As Stein explained to POWER on Monday, Framework B’s evolution arose from stakeholder feedback that having an option that aligns with international standards would be beneficial. However, “Instead of enabling that alignment through guidance, as an optional approach to meeting the requirements in Part 53, the NRC made a second framework inside of Part 53,” he noted. “That created several challenges, including that Framework B was a traditional deterministic and prescriptive approach instead of the risk-informed and performance-based approach required by NEIMA.”

By removing the option, “we’ve got a framework that really leads with probabilistic and risk information in a leading role,” Hanson told reporters on Monday. “That’s one of the big things: It provides flexibility for applicants to propose a cumulative risk standard. So, if you think about probabilistic risk assessment, where you are quantifying the likelihood and consequences of various kinds of events, at the end of that, then you want to have a metric in terms of the frequency as it impacts the public. What we’ve done is say, ‘there’s a lot of historical work in the NRC on that going back to our 1986 safety goal policy statement, [let’s] have something that’s consistent with that overall … safety goal policy statement, but you get to propose what your metric will be.’”

Streamlining the Rule: From QHOs to Factory Fuel Loading

The commission on Monday notably also directed staff to specify in its proposed rule that applicants must propose “a comprehensive plant risk metric (or set of metrics) and a description of the associated methodology used to demonstrate that the proposed design meets said metric(s).”

QHOs “were not a viable metric in a performance-based rule,” Stein explained (more technical basis here and here). “Instead, developers will have to provide their own metric that is specifically not intended as a real-time requirement—a major legal flaw with the draft,” he said. “This approach creates more flexibility for new technologies but has less regulatory predictability. Clear guidance will be the key—along with clear communication by both applicants and the NRC—to making this approach work.”

In addition, the commission also reversed several current regulatory programs. “The generic issues program and others, we think are adequate, and therefore, the facility safety program (FSP) that was proposed by staff is also not necessary,” Hanson noted. The draft’s FSP had previously called for routine assessments of potential changes to plant hazards. At the same time, he said the commission retained ALARA (as low as reasonably achievable), an occupational hazard principle, as programmatic requirements rather than a design requirement.

As notably, the commission directed the staff “to consider and include other rulemakings that have been finalized or have made progress while Part 53 was being developed,” Stein said. These include the Emergency Preparedness for Small Modular Reactors and Other New Technologies, loading fuel under a manufacturing license for testing, and other areas.

According to Hanson, one of the most significant differences compared to the draft proposal has been the commission’s directive to its staff “to take another look at fuel loading in a factory for microreactors to be incorporated into the proposal.” That will entail looking at the NRC’s existing regulations and proposing “some additional rule changes for how microreactors can be fueled and tested within the factory,” he said.

Predictability and Efficiency for Advanced Nuclear

The nuclear industry has largely welcomed the NRC’s measure. The Nuclear Innovation Alliance (NIA), a think tank dedicated to enabling advanced nuclear power as a global solution to mitigate climate change, said the vote marked an “important step forward in creating a regulatory framework for advanced reactors that can provide both regulatory flexibility and predictability for advanced reactors and enables the commercialization and deployment of advanced nuclear energy.”

“The vote by the Commission directs the NRC staff to remove several new regulatory requirements that were added in 10 CFR Part 53 (e.g., new operational programs), clarifies the implementation of important regulatory requirements (e.g., use of probabilistic risk assessment), and emphasizes that the new rule for advanced reactors should leverage existing regulatory requirements (e.g., quality assurance programs) where appropriate and applicable,” Patrick White, research director at NIA, told POWER.

“NIA believes this clear direction from the Commission will help clarify the intent of the draft proposed rule for 10 CFR Part 53 and realign NRC staff and external stakeholders as we continue the rulemaking process,” he said. The NRC’s crucial next steps will entail staff collaboration with external stakeholders to develop new comprehensive risk metrics that will be used to help assess the safety of advanced reactors, he noted.

Advanced reactor developers—such as Kairos, X-energy, TerraPower, and Abilene Christian University—are currently pursuing demonstration projects under Part 50, White noted. “And there are a number of developers that are going through the process through the regulatory exemption process.  So, they take a look at what the regulations are in Part 50, and even though they were optimized for large LWRs, they work with the NRC to determine what requirements are appropriate and what requirements would need to change with the review of their technologies,” he said.

Assuming the NRC will meet its 2027 statutory deadline for Part 53, White suggested the new framework should provide more predictability and much more regulatory efficiency for advanced reactors. “So when we talk about the timing, as we start talking about trying to deploy advanced reactors in greater numbers, that’s when the Part 53 framework can become really useful,” he said.

—Sonal Patel is a POWER senior associate editor (@sonalcpatel, @POWERmagazine).

Updated (March 5): Includes comments from NIA. 

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