Arco, Idaho: The World's First Nuclear-Powered Town

The small town of Arco, Idaho, sits on the edge of the Snake River Plain with the Lost River Range rising behind it to the north. Population around nine hundred. There is a grain elevator and a diner and a high school, and on the cliff face above town, the graduating class of each year has painted its year in whitewash since nineteen twenty. The painted years go back more than a century, layered up the rock like a timeline.

On July seventeenth, nineteen fifty-five, the reactor at the National Reactor Testing Station outside town briefly powered the entire municipality of Arco from nuclear fission, the first time any town anywhere in the world had been lit by atomic energy. The demonstration lasted approximately one hour. But it worked, and the engineers running it knew what they had done.

The demonstration was made possible by the Experimental Breeder Reactor One, which had first generated nuclear electricity in December of nineteen fifty-one, just a few miles down the highway. Arco was the proof-of-concept made municipal: if a reactor could power a whole town, even for one hour, the argument for nuclear power generation as a practical technology was no longer theoretical.

Arco added nineteen fifty-five to its painted cliff. It sits there with the graduation years around it, the most important date in the series, and most people driving through stop at the diner and do not notice.