10 CFR Part 50, formally titled "Domestic Licensing of Production and Utilization Facilities," is the NRC's original and longest-standing regulatory framework for licensing nuclear power plants. Under Part 50, the licensing process follows two distinct steps: first, the applicant must obtain a Construction Permit (CP) by submitting a Preliminary Safety Analysis Report demonstrating that the proposed design can be built safely at the chosen site; second, after construction is substantially complete, the applicant submits a Final Safety Analysis Report and applies for an Operating License (OL) authorizing fuel loading and power operations. Every commercial nuclear power plant currently operating in the United States was originally licensed under Part 50.
Despite the availability of the newer Part 52 combined licensing framework, several leading advanced reactor developers have chosen the Part 50 pathway for their demonstration projects. Kairos Power obtained its Construction Permit for Hermes under Part 50 in December 2023, and TerraPower received its Natrium CP under Part 50 in 2025. Holtec International's partial CP application for the SMR-300 at Palisades, submitted in December 2025, also follows the Part 50 route. The strategic rationale is schedule-driven: Part 50 allows construction to begin after CP issuance while the operating license review proceeds in parallel, potentially shortening the overall project timeline for first-of-a-kind plants where design evolution may occur during construction.
The two-step Part 50 process does carry risks that the Part 52 COL was designed to mitigate. Historically, some plants completed construction under a CP only to face protracted operating license hearings, design modification requirements, or outright denial, resulting in multi-billion-dollar stranded assets. However, the current regulatory environment is substantially different from the contentious licensing battles of the 1970s and 1980s. The NRC has established clearer review standards, and the advanced reactor community benefits from extensive pre-application engagement with the agency. The forthcoming Part 53 framework is expected to provide a third option that is technology-inclusive and risk-informed, potentially offering the most efficient pathway for non-light-water advanced reactors when it becomes available after 2027.