TerraPower's Natrium reactor uses molten salt storage to power AI data centers

Bill Gates-founded TerraPower is positioning its Natrium reactor as the answer to AI data centers' power reliability problem, with plans to announce its first data center project this year. The 345-megawatt molten salt-cooled reactor features a unique molten sodium storage tank that lets it keep splitting atoms at full capacity even when demand drops. Instead of ramping up and down like conventional reactors—which can adjust only about 5% of rated output per minute—the reactor stores excess heat as molten sodium and releases it to spin turbines when data center loads spike. This design sidesteps a core challenge: nuclear plants have the highest capital expenditures of any power generation technology, so operating at peak capacity as often as possible is essential for profitability.

TerraPower's storage approach was originally designed to complement intermittent renewables like wind and solar, but it turns out to be equally well-suited for AI data centers, whose GPU-driven power loads can swing dramatically during training or inference. The flexibility avoids the need for massive battery banks and reduces stress on grid infrastructure—natural gas turbines have literally broken under these conditions. Meta has already agreed to purchase eight Natrium plants in January 2025, and TerraPower's first unit is under construction in Wyoming, with the data center project expected to break ground in 2027. By combining nuclear's 92.5% capacity factor with thermal storage, TerraPower aims to offer always-available, carbon-free power that can ramp quickly, giving it a competitive edge over other nuclear startups in the race to power AI.