United States of America is modernizing reactor licensing, safety oversight, and siting practices to enhance nuclear energy regulation through safer and more efficient approaches including updates to the Nuclear Licensing Platform, Safety Oversight System, Reactor Siting Tool, Modernized Reactor Certification, Modern Siting Tool, and Reactor Compliance Suite
The U.S. Nuclear Regulatory Commission has published a sweeping overhaul of reactor licensing, safety oversight and siting rules, cutting the time and cost of bringing new nuclear plants online while tightening safety thresholds for existing ones. The changes, set out in a 157-page proposed rule published on 16 July 2026, take effect on 27 July 2026 and are open for public comment until 31 August 20261. They cover everything from reactor design changes to emergency planning, and are the first major rewrite of the agency’s licensing framework in more than a decade.
The rule targets the delivered cost of new nuclear capacity by slashing redundant paperwork, streamlining site approvals and introducing risk-informed safety margins. It also raises the bar for existing plants, requiring them to meet new, data-backed thresholds for design-basis events and beyond-design-basis events. The NRC estimates the changes will save the industry $1.2 billion over the next ten years in reduced licensing and compliance costs1. Who pays for the remaining costs shifts with the rule: new entrants will see lower upfront fees, while incumbent operators will bear the cost of retrofitting safety systems to meet the new thresholds.
It comes after Executive Order 14300, issued in January 2025, directed the NRC to modernise its regulations to accelerate the deployment of advanced reactors. The order set a two-year deadline for the agency to adopt “determinate and data-backed thresholds” for safety assessments, eliminate redundant requirements and align its licensing process with the risk profiles of next-generation designs. The NRC said in a statement that the proposed rule “strikes a balance between regulatory certainty and the flexibility needed to deploy innovative technologies”1.
The licensing overhaul: what changes on 27 July
The rule amends eight parts of Title 10 of the Code of Federal Regulations (10 CFR Parts 2, 50, 51, 52, 53, 54, 71 and 100)2. The most immediate change is the withdrawal of a 2025 guidance document that contained outdated information on reactor siting and environmental reviews. The correction, published in the Federal Register on 27 July, removes the old guidance and replaces it with a new set of regulatory guides that reflect the risk-informed approach of the proposed rule2.
The rule, for new plants and existing ones
| Question | New reactors | Existing plants |
|---|---|---|
| Site review | Graded, design-tailored | Retrofit to new thresholds |
| Early site permits | 20 to 30 years | Not affected |
| DBE / BDBE thresholds | Built into design | Within 5 years of effective date |
| Minor design changes | No prior NRC approval, Parts 52/53 | Not affected |
For new reactors, the rule introduces a “graded” site-characterisation process that tailors the depth of environmental review to the reactor’s design and location. Under the new process, a small modular reactor sited on an existing nuclear site will face fewer upfront studies than a large light-water reactor proposed for a greenfield site. The NRC said the change will cut the average site-permitting timeline by 18 months1. Early site permits, which allow developers to secure a site before finalising reactor design, are also extended from 20 to 30 years1.
Existing plants face tighter safety margins. The rule adds two new definitions to 10 CFR 50.2: “design basis event” (DBE) and “beyond design basis event” (BDBE)1. DBEs are now defined as events that a plant must be designed to withstand without exceeding safety limits, while BDBEs are events that exceed those limits but must still be managed to prevent core damage. The NRC said the definitions will “focus safety assessments on credible, realistic risks” and eliminate the need for plants to analyse events with probabilities below 1 in 10 million per reactor-year1.
Who the new thresholds hit
The new safety thresholds apply to all commercial nuclear power plants, but the burden falls heaviest on the 93 operating reactors in the U.S. fleet. Plants that reference a certified design under 10 CFR Part 52 will see fewer changes, as the rule preserves the design certification’s original safety margins. Plants licensed under 10 CFR Part 50, however, must now demonstrate that their safety systems can withstand the new DBE and BDBE thresholds within five years of the rule’s effective date1.
Who the new thresholds hit
The rule also revises the emergency preparedness (EP) framework for nuclear power reactors. It introduces “adaptable licensing pathways” that allow plants to tailor their emergency plans to the reactor’s design and location. For example, a plant sited in a low-population area may now use a smaller emergency planning zone than a plant in a densely populated region. The NRC said the change will reduce the cost of EP compliance by up to 30% for plants that can demonstrate a lower risk profile1.
The paperwork cuts: what goes, what stays
The rule eliminates or modifies more than 200 reporting and recordkeeping requirements across seven parts of 10 CFR. The biggest cuts are in 10 CFR Part 30, which governs the licensing of byproduct material. The rule creates a new “low-burden” class of standard general licences (GLs) that exempts licensees from annual reporting requirements if they meet certain safety criteria3. It also revises the decommissioning financial assurance tables, cutting the number of required reports from 12 to 43.
Savings the rule promises, USD
For reactor licensees, the rule removes redundant requirements in 10 CFR Parts 50 and 52. For example, it eliminates the need for plants to submit separate environmental reports for each licence amendment, replacing them with a single, consolidated report that covers all changes made during a licensing cycle. The NRC said the change will save licensees $50 million per year in reduced paperwork costs1.
The rule also streamlines the process for changing reactor designs during construction and operation. Under the new framework, plants licensed under 10 CFR Part 52 or 53 can make “minor” design changes without prior NRC approval, provided the changes do not affect the plant’s safety margins. The NRC defines a minor change as one that affects less than 5% of the plant’s safety-related systems1.
The industry pushback: what the documents reveal
The NRC’s proposed rule has drawn sharp criticism from the Nuclear Energy Institute (NEI), the industry’s main trade group. In a 27 July comment letter, NEI said the rule’s new safety thresholds could “effectively preserve the existing prescriptive expectations” for existing plants, undermining the rule’s goal of reducing regulatory burden4. NEI also criticised the NRC’s use of regulatory guides (RGs) to impose new requirements, arguing that the guides “strongly encourage” licensees to follow them, leaving little room for alternative compliance methods.
The industry group also took issue with the rule’s treatment of “vital areas” and “vital equipment” in 10 CFR 73.55, which governs physical protection of plants. NEI said the terms are “vague and overly broad” and could be used to impose new security requirements on plants without clear justification4. The NRC has not yet responded to the comments, but the agency said in a statement that it will consider all feedback before issuing a final rule.
What comes next: the 2028 review and beyond
The rule sets a 1 March 2028 deadline for the NRC to complete a comprehensive review of its implementation1. The review will assess whether the new safety thresholds are achieving their intended goals and whether the paperwork cuts are delivering the promised cost savings. The NRC will also evaluate the rule’s impact on the deployment of advanced reactors, including small modular reactors and microreactors.
Dates the industry must watch
The rule’s long-term success hinges on its ability to balance flexibility with safety. The NRC said the changes are designed to “future-proof” the licensing process, allowing it to accommodate new reactor designs without sacrificing public safety. But the industry’s early pushback suggests the rule’s implementation will be closely watched, and further revisions may be needed to address concerns about regulatory overreach. For now, the clock is ticking: the rule’s first deadlines for existing plants fall in mid-2027, and the industry has less than two years to prepare.
Sources
- ↩ Modernizing Reactor Licensing, Safety Oversight, and Siting Practices — 2026 14341 / modernizing reactor licensing safety oversig… https://www.federalregister.gov/documents/2026/07/16/2026-14341/modernizing-reactor-licensing-safety-oversight-and-siting-practices
- ↩ Modernizing Reactor Licensing, Safety Oversight, and Siting Practices — imrd / directdoc https://docs.wto.org/imrd/directdoc.asp?DDFDocuments/T/G/TBTN26/USA2303C1.docx
- ↩ Modernizing NRC Regulations for Byproduct Material Use https://www.federalregister.gov/documents/2026/05/18/2026-09877/modernizing-nrc-regulations-for-byproduct-material-use
- ↩ Rulemakings and Adjudications Staff Staff Summary https://downloads.regulations.gov/NRC-2025-1303-0085/attachment_1.pdf