TerraPower's Wyoming reactor gets digital twin to train operators

In Kemmerer, Wyoming, a full-scale digital simulator has arrived at the construction site of TerraPower's Natrium reactor. Built by Curtiss-Wright, the system is an exact digital twin of the future plant, and it gives technicians their first hands-on access to its controls, well before the reactor goes live in 2030.

Training is the hurdle. The simulator runs on a software engine called 3KEYMASTER, which models the physics in real time: how fluids circulate, how temperatures shift, and how the core reacts when equipment trips unexpectedly. Operators can rehearse emergency drills, test automated safety actions and log the hours required for federal operating licenses, all before a single fuel assembly is loaded.

The design explains why. Most US nuclear plants cool their cores with light water under intense pressure. Natrium uses liquid sodium instead, which carries heat efficiently and boils at nearly 900°C, so the system runs at close to normal atmospheric pressure. That removes the need for the massive, thick-walled containment domes that define conventional stations. The plant also separates power generation from nuclear heat: the reactor supports a baseline output of 345 megawatts, and surplus heat goes into molten salt tanks. When demand spikes, operators draw on that stored heat to raise electrical output to 500 megawatts for over five hours, without changing the reactor core's baseline.

The simulator doubles as a testbed. Curtiss-Wright is also building the plant's control systems, including its Distributed Control Systems and an automated Reactor Protection System. Running those programs through the simulator lets technicians find software bugs and verify hardware responses years before fuel loading.

For the operators who will staff the plant, the change is that they arrive with hours already logged on the real controls, rather than learning them on live equipment. If the Kemmerer site proves viable, TerraPower intends to use the same operating model for commercial fleets across the country, and George Piccard, the company's Vice President of Plant Operations, said the simulator is meant to “scale a qualified nuclear workforce across every future Natrium plant.” The timetable depends on that viability test, and the company has not given a date for the first fleet.