Experimental Breeder Reactor I

Experimental Breeder Reactor I, or EBR-I, near Arco, Idaho, was built at Argonne National Laboratory’s Idaho site under Walter Zinn and became the world’s first breeder reactor as well as one of the earliest nuclear plants to generate electricity. In December 1951 it first lit four bulbs, then powered its entire building the next day. Designed to test Enrico Fermi’s idea that a reactor could produce more fissile fuel than it consumed, it used enriched and natural uranium in a fast-neutron system. Despite a partial meltdown in 1955, it was repaired, operated until 1964, and was later preserved as a U.S. National Historic Landmark.

Idaho · United States