The U.S. Nuclear Regulatory Commission (NRC) has accelerated the pace of nuclear innovation, completing its draft safety evaluation (SE) for TerraPower’s Kemmerer Power Station Unit 1, a groundbreaking 345-MW sodium-cooled fast reactor (SFR) in Wyoming. This milestone, achieved a month ahead of schedule, underscores the potential for advanced nuclear technologies to reshape the energy landscape. The NRC’s draft SE, initially anticipated by March 2025, was expedited through productive engagement with TerraPower’s subsidiary, US SFR Owner, LLC (USO). The final SE is now targeted for June 2026, with the environmental review separately on track for completion in May 2026. TerraPower anticipates receiving NRC approval in late 2026, paving the way for construction to commence in early 2027.
Kemmerer 1, situated near PacifiCorp’s Naughton Power Plant, is poised to receive up to $2 billion in funding under the Department of Energy’s Advanced Reactor Demonstration Program (ARDP). This hybrid nuclear facility will integrate TerraPower’s first Natrium reactor, an 840 MWth pool-type Natrium SFR reactor, with a nitrate molten salt-based energy storage system. This innovative design could boost the system’s output to between 100 MWe and 500 MWe of power for over 5.5 hours, ramping at 10% a minute. The NRC’s draft SE, while a significant step, has identified several outstanding issues that TerraPower must address. These include materials qualification for environmental compatibility, special treatment requirements for safety-significant structures, systems, and components, and the seismic/structural design approach for non-safety-related systems. The NRC has also requested additional documentation on the Probabilistic Risk Assessment (PRA) within the Licensing Modernization Project (LMP) and other licensing programs. The LMP aims to modernize the regulatory process for non-light water reactors by incorporating risk-informed approaches. The NRC’s request for further PRA documentation indicates a close evaluation of how TerraPower is applying risk insights to safety classifications and regulatory decision-making, a critical factor in the licensing of first-of-a-kind (FOAK) reactors like Natrium.
When comparing the identified open items to those typically encountered in licensing reviews for conventional nuclear plants, the NRC stated that open items are an expected part of draft safety evaluations, particularly for complex topics requiring additional analysis before final technical decisions. “The TerraPower application used the Licensing Modernization Project approach, which means some topics can apply to several review areas. When those topics are resolved, multiple parts of the evaluation will be addressed simultaneously. Issues such as materials qualification and PRA documentation have been open items in the past,” agency spokesperson Scott Burnell said. The early draft evaluation is a result of the NRC’s extensive pre-application discussions and ongoing technical exchanges with TerraPower. Burnell added that the agency expects lessons learned during this review to lead to efficiency improvements down the road, whether for additional TerraPower applications or for other vendor submissions. For example, this continuous improvement effort bore significant results in completing the review of the second Kairos construction permit application several months faster than the first Kairos review.
This development in the Kemmerer Power Station Unit 1 project is not just a regulatory milestone but a harbinger of a new era in nuclear energy. The successful integration of advanced reactor technologies with energy storage systems could revolutionize the way we think about nuclear power. The ability to ramp up power output quickly and efficiently aligns with the growing demand for flexible, reliable energy sources. This project could set a precedent for future nuclear developments, demonstrating the feasibility of advanced reactors and their potential to integrate seamlessly with renewable energy sources. The NRC’s proactive engagement and TerraPower’s innovative approach highlight a collaborative spirit within the nuclear sector, one that is essential for driving progress and innovation. As the project moves forward, the lessons learned and efficiencies gained will undoubtedly shape the future of nuclear energy, paving the way for more advanced and efficient reactors. The ongoing dialogue between regulators and developers is crucial for navigating the complexities of licensing FOAK reactors and ensuring that safety remains paramount. This project serves as a testament to the potential of advanced nuclear technologies to transform the energy sector, offering a glimpse into a future where nuclear power plays a pivotal role in a sustainable energy mix.
