TerraPower’s nuclear reactor has a secret weapon for powering AI data centers

For data centers, especially those that rely on behind-the-meter power, that poses a challenge. Their loads, especially when training AI or responding to prompts, can sink and soar quickly as GPUs respond to the tasks. The swings are so demanding that natural gas turbines have been breaking under the stress. To smooth the curve, they need to use large banks of batteries, which increase costs further.

TerraPower designed its 345-megawatt molten salt-cooled reactor to work around those challenges. One of the key considerations was ensuring the reactor could complement intermittent sources of electricity like wind and solar — the power plant needed to ramp up and down quickly. While TerraPower had renewable power, not data centers, in mind when it sketched its plans, the two are similarly intermittent, just on different sides of the equation.

To ramp quickly, TerraPower doesn’t increase or decrease the power output of its reactor. Rather, it keeps on splitting atoms, and the extra heat gets stored in a giant vat of molten sodium. When power demand spikes, the power plant can tap that reservoir to generate more steam to spin the turbines. The expensive equipment keeps working even when demand is low, allowing the company to amortize its investment over more operational hours.

The approach takes the best of nuclear power — high capacity factor — and pairs it with an energy storage technology that allows TerraPower to play nicely on a renewable-heavy grid or when connected to an data center. It’s a flexible approach that could give the startup an advantage in the race to power AI.