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TerraPower Natrium Nuclear Reactor Gets NRC Construction Approval at Kemmerer, Wyoming Site

Canopy Hardware
Construction site near a coal plant in Wyoming where TerraPower's Natrium sodium-cooled nuclear reactor will be built

The US Nuclear Regulatory Commission (NRC) issued a construction permit to TerraPower on March 4, 2026, for the Natrium sodium-cooled fast-neutron reactor in Kemmerer, Wyoming — the first new nuclear construction approval in nearly a decade. The Natrium design, developed jointly with GE Hitachi and backed by Bill Gates, uses liquid sodium coolant instead of pressurized water, allowing lower-pressure primary circuits at the cost of heightened chemical reactivity risks. The plant is not expected to be operational before 2030 and will still require an operating license before generating power.

Key Takeaways

  • NRC issued Natrium construction permit March 4, 2026 — first US nuclear construction permit in ~10 years; site is Kemmerer, Wyoming, using existing coal plant transmission infrastructure
  • Natrium is a sodium-cooled, fast-neutron reactor with integrated molten-salt thermal energy storage; design joint venture between TerraPower (Bill Gates) and GE Hitachi
  • Construction approval does not include an operating license; operational target is 2030 at the earliest, with further NRC review required before fuel loading

Original source: Ars Technica