TerraPower just moved its Natrium reactor closer to operation. On August 21, South Korea’s Doosan Enerbility signed a contract to manufacture core reactor components for the TerraPower Natrium reactor going up in Kemmerer, Wyoming. The deal covers the core barrel, the guard vessel, and the internal supports that hold the reactor’s core in place, according to World Nuclear News.
This isn’t a routine supplier announcement. Doosan Enerbility already forges heavy reactor components for plants around the world, so it isn’t learning on the job. It’s applying manufacturing muscle it has already proven elsewhere to a brand-new reactor design, and that cuts real risk out of the build.
Why the TerraPower Natrium reactor design pushes fission forward
The TerraPower Natrium reactor pairs a 345-megawatt sodium-cooled fast reactor with a molten salt energy storage system. That storage tank can push output up to 500 MWe whenever the grid needs a burst of power. A conventional nuclear plant runs at one fixed output around the clock. Natrium banks heat when demand is low and releases it fast when demand spikes, so it behaves almost like a battery bolted onto a reactor.
Sodium coolant also runs at far lower pressure than the water inside a traditional reactor. Lower pressure simplifies the containment structure and removes some of the failure modes that keep regulators cautious about new designs. Engineers get a reactor that’s both more flexible on the grid and structurally simpler to build.
A concrete step, not a press release
Component contracts like this one separate real projects from paper reactors. Doosan says years of joint engineering work with TerraPower have pushed its designs to “manufacturing-ready” status, meaning the blueprints are now buildable specs, not concepts. Non-nuclear construction at Kemmerer started back in 2024, and the project still targets commercial operation by 2030.
Feeding this reactor will also take a steady supply of high-assay low-enriched uranium, or HALEU. That fuel pipeline is still catching up with demand from projects like this one. We’ve tracked that squeeze in depth in our look at the state of nuclear fuel supply in 2026. Enrichment capacity is expanding to help close that gap, including through projects like Urenco’s newly expanded US enrichment plant.
Why this milestone matters
Kemmerer is on track to be the first utility-scale advanced reactor built in the United States. Every manufacturing contract that lands moves that milestone from a plan on paper toward steel in the ground. It also signals something bigger. International manufacturers now see the advanced reactor market as real enough to invest engineering time, not just sales pitches.
If Natrium succeeds, it proves two things at once. A sodium-cooled fast reactor can run safely at commercial scale, and a reactor with built-in energy storage can solve the flexibility problem that intermittent renewables create on the grid. That combination is why this small supply-chain deal carries outsized weight for nuclear fission technology.
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