TerraPower's nuclear plant stores heat in molten salt. That could make it ideal for AI data centres.
The Bill Gates-founded startup plans to announce its first data centre deal this year. Its trick: keeping the reactor running flat-out while banking spare heat for the moments when demand spikes.
Key points
- TerraPower, the nuclear startup founded by Bill Gates, plans to announce its first data centre power project in 2025, with construction expected to begin in 2027.
- In January 2025, Meta agreed to buy eight of TerraPower's Natrium reactors, each rated at 345 megawatts.
- TerraPower's reactor stores surplus heat in a tank of molten sodium, letting it deliver extra electricity on demand without slowing the reactor down.
- American nuclear reactors run at full power 92.5 percent of the time, a higher rate than any other type of power plant.
- Unlike most nuclear plants, TerraPower's design can ramp output up and down quickly, making it compatible with grids that rely heavily on wind and solar.
Power is the bottleneck. Every company racing to build AI infrastructure is hunting for electricity that never stops flowing, and a growing number of nuclear startups say they are the answer. TerraPower, the company Bill Gates founded, is about to make that pitch more concrete.
First reported by Bloomberg, TerraPower plans to announce its first data centre power project later this year. The company did not name the customer. Construction is expected to start in 2027, making it TerraPower's second plant after the one already being built in Wyoming.
Why does a nuclear plant need a heat battery?
AI workloads are electrically erratic. Training a large AI model, the kind of software behind chatbots like ChatGPT, pulls an enormous amount of power. Then it stops. GPUs, the specialised chips that do the heavy number-crunching AI needs, can swing from nearly idle to full power and back in minutes. That whiplash is so severe that natural gas turbines supplying some data centres have broken under the stress.
Nuclear reactors have the opposite problem. They run best when left alone at full output. A traditional reactor can only increase or decrease its output by about 5 percent of its total capacity per minute, which makes chasing a spiky data centre load nearly impossible.
TerraPower's solution is to stop trying to match demand in real time. Instead, the reactor keeps splitting atoms at a steady pace. Any heat it produces that the grid does not immediately need gets diverted into a large tank of molten sodium, a metal that holds heat exceptionally well. When a data centre's demand suddenly surges, the plant draws on that stored heat to boil more water, spin its turbines faster, and push out extra electricity within minutes.
The reactor itself never slows down. All the expensive equipment keeps earning its keep.
What does this mean for AI companies shopping for power?
Data centres trying to run off their own dedicated power supply, rather than drawing from the public grid, need generation that can follow their load. Batteries can help smooth the peaks, but large battery banks add significant cost. TerraPower's molten-sodium storage does that smoothing job as part of the plant's basic design.
The company originally developed this feature to pair its reactor with wind and solar farms, sources that produce power only when the wind blows or the sun shines. A data centre's demand swings turn out to create a similar matching problem, just from the other direction.
TerraPower still faces the challenge every nuclear startup faces: its early plants will be expensive. Small modular reactors, compact factory-built nuclear units that many startups are pursuing, promise lower costs through mass production, but that benefit is years away. Running the plant at maximum output as often as possible is the only way to make the economics work in the near term.
Meta's January commitment to buy eight Natrium plants signals that at least one major AI company sees the deal as worth making.
Common questions
Is this nuclear power safe for communities near data centres?
TerraPower's Natrium reactor uses molten sodium as a coolant rather than pressurised water. Sodium-cooled reactors have operated commercially before, and the design is regulated by the US Nuclear Regulatory Commission. The Wyoming plant under construction will be the first modern demonstration of this specific design.
When would this actually deliver power?
TerraPower expects to break ground on the data centre project in 2027. Nuclear plants typically take several years to build after construction begins, so commercial power from this project is unlikely before the early 2030s.
