The U.S. Nuclear Regulatory Commission (NRC) has formally proposed a new licensing framework, designated as 10 CFR part 57, to accelerate the deployment of microreactors and small-scale nuclear technologies. This rule aims to create a risk-informed, performance-based pathway for reactors with limited fuel inventories and lower potential offsite consequences, with public comments accepted through June 15, 2026, under Docket ID NRC–2025–0379.
Why is the NRC creating a new regulatory part?
The NRC determined that existing frameworks, specifically 10 CFR parts 50 and 52, were designed primarily for large-scale light-water reactors. According to the Commission, those legacy rules impose requirements that are often unnecessary for smaller, passive, or transportable reactor designs. While part 53 was considered for a broader class of advanced reactors, the agency concluded that a dedicated, streamlined framework is necessary to support the “rapid licensing and high-volume deployment” of microreactors intended for remote communities, industrial heat, and military sites.
What are the eligibility requirements for part 57?
Not every advanced reactor will qualify for this expedited pathway. The NRC proposes two primary “entry criteria” to screen for low-consequence designs:
- Dose Criterion: Applicants must demonstrate that the reactor satisfies a 1 rem total effective dose equivalent at the site boundary under accident conditions.
- Fuel Mass Limit: The NRC proposes a 10 metric ton limit on the total inventory of thorium, uranium, and plutonium.
The agency is actively seeking industry feedback on whether a deterministic material limit is appropriate or if a performance-based metric would better serve the objective of limiting decay heat challenges.
How will this change the licensing process for developers?
The proposed part 57 emphasizes standardization and joint applications to compress the timeline from submittal to operation. According to the NRC, a well-prepared joint application for a construction permit and operating license could lead to an operating license within 6 to 12 months, provided the application is complete and hearing contentions are resolved quickly. This represents a significant shift from traditional timelines that often span several years.
What should stakeholders prioritize before the June 2026 deadline?
Entities involved in the nuclear fuel cycle, reactor manufacturing, or industrial energy sectors should evaluate how their current design specifications align with the proposed entry criteria. The NRC has invited specific comments on several “make-or-break” issues, including the feasibility of remote and autonomous operations, the proposed fitness-for-duty requirements for staff, and the criteria for transporting fueled microreactors. Engaging with the docket now allows developers to influence the final rule language, which will dictate the commercial viability of these projects for decades.
Frequently Asked Questions
- Is there a general license for building these reactors?
- No. The NRC concluded that the Atomic Energy Act does not authorize a general license for the construction of an entire reactor. However, the rule proposes a limited general license for specific construction activities for “nth-of-a-kind” facilities.
- How does this affect emergency planning?
- The NRC does not intend to define an emergency planning zone for facilities licensed under part 57, citing the low-consequence nature of the designs.
- Can I operate these reactors remotely?
- The proposal explicitly allows for remote monitoring, remote operation, and autonomous operation. The NRC is seeking input on what additional safeguards or regulatory guidance are necessary for these modes.
Are you planning to submit comments on the proposed 10 CFR part 57? Share your perspective or questions in the comments section below to join the industry discussion on the future of microreactor deployment.
