TerraPower’s molten-salt reactor designed to handle data center power swings with molten sodium storage

TerraPower, a nuclear power startup founded by Bill Gates, plans to announce its first data center power project in 2026, with construction expected to begin in 2027, according to a TechCrunch report citing Bloomberg. The company did not name the customer, but in January it announced that Meta had agreed to buy eight of its Natrium power plants.

The company’s 345-megawatt molten salt–cooled reactor is engineered to complement intermittent renewable sources like wind and solar by ramping output quickly. Unlike conventional reactors that struggle to adjust output, TerraPower keeps the fission reaction constant and stores excess heat in molten sodium. When demand spikes, the plant taps this reservoir to generate additional steam for turbines, avoiding wear on the reactor itself.

Nuclear reactors typically operate at very high capacity factors—about 92.5% in the U.S.—but their ability to ramp output is limited. Existing reactors can change output by roughly 5% of rated capacity per minute, while newer small modular reactors (SMRs) may manage about 10% per minute, according to the National Laboratory of the Rockies (NLR).

Data centers, especially those running AI workloads, experience rapid power swings as GPUs ramp up and down. Many rely on natural gas turbines or large battery banks to smooth demand, adding cost and complexity. TerraPower’s approach aims to provide steady baseload power with rapid response capability, potentially lowering costs for behind-the-meter data center power.

The startup acknowledges early plants will be expensive, but argues that operating at near-full capacity more often can help amortize capital costs. Its molten sodium storage system decouples power generation from immediate reactor output, offering a flexible solution for both renewable-heavy grids and data centers with volatile loads.