The Stationary Low-Power Reactor Number One (SL-1) accident stands as a somber and critical chapter in United States nuclear history. Occurring on January 3, 1961, at the National Reactor Testing Station (NRTS) near Idaho Falls, Idaho, it marks the first fatal nuclear reactor incident in American history.

The Cold War Context and Design Imperatives

During the 1950s, as the United States engaged in the intense period of the Cold War, the U.S. Army needed a reliable source of power for remote military outposts. The goal was to power sites like the Distant Early Warning (DEW) Line radar stations along the Arctic frontier—places far removed from existing electrical grids. This need gave rise to SL-1, a prototype designed to be a small, transportable