Newly appointed NRC Chairman, Ho Nieh, said “This is really a historic milestone. With the addition of Part 53 to Part 50 and 52—and I believe some of you know that we’re working on a microreactor licensing framework—America now has many options available to applicants and licensees that want to pursue the development and deployment of new nuclear technologies.” This final rule from the NRC action is intended to provide a clear risk-informed, technology-inclusive licensing framework that enables advanced nuclear designs to move from concept to construction more rapidly and safely.

Part 53’s shift from a technology-specific to a technology-neutral approach to reactor licensing is intended to address a long-standing issue in regulatory frameworks that were developed specifically for light water reactor technology. Licensing reactors that do not use LWR technology has required applicants to seeking regulatory exemptions to many burdensome prescriptive requirements, leading to a cumbersome licensing process.

“Part 53 offers a comprehensive new approach to license advanced reactors, including non-light-water reactors, across their life cycles,” according to the NRC release. “It provides designers and operators with more flexibility in how they build and run their plants while continuing to ensure safety.”

This week’s announcement comes more than a year after the NRC first published their Part 53 proposed rule, which was widely viewed as not being the solution the industry was looking for. Some 158 public comments were accepted including from Westinghouse, The Breakthrough Institute, the Nuclear Energy Institute, the Idaho National Laboratory and many others. Apparently, the newly revised rule incorporated many of the changes requested by commenters and eliminated sections of the rule that some parties deemed unusable.  Nieh said the final version of Part 53 addresses many of the complaints and comments he and the NRC heard regarding earlier versions of the rule. “I do believe this framework does provide the appropriate flexibility and risk-informed approaches that will make it a usable tool among the other options that are already available,” said Nieh.

According to Acting Deputy Office Director for New Reactors Jeremy Bowen,  Part 53 could enable reactor designs to receive approval in 18 months or less. The cost of the application could be reduced by half or more, given the shorter review and the added flexibility of Part 53. A 2023 analyses of the earlier draft regulation estimated the net averted costs to the industry and the agency for just one applicant could range from $53.6 million to $68.2 million, which may be bigger under the updated final rule.

History: Part 53 is the first new reactor licensing framework issued by the NRC since 1989, when the agency introduced Part 52. NRC officials added that it is the first major update to reactor licensing standards since 1956, when the Atomic Energy Commission (the NRC’s predecessor) issued Part 50. The final rule’s has been long awaited by the industry but, even with the five year time frame that it took, was issued ahead of the 2027 deadline ordered by NEIMA. Today's rules will hopefully update rules that were put in place many, many decades ago that were being used to license the first wave of nuclear reactors built in the United States in the ’60s and ’70s. Said Ho, "We did not know as much about the technology [then] that we know today, where we [did] not have the sophistication and analytical tools to evaluate safety cases that we have today. . . . To me, I see this as removing the friction in legacy frameworks that are no longer needed today.”

According to the NRC website, the Part 53 final rule will be published on April 3, and the rule will go into effect 30 days after it appears in the Federal Register. As part of the posting, the NRC will publish nine additional guidance documents, with additional guidance to follow.