B Reactor can take a tour of the reactor by advance reservation. The reactor was designed and built by E. I. du Pont de Nemours and Company based on experimental designs tested by Enrico Fermi at the University of Chicago, and tests from the X-10 Graphite Reactor at Oak Ridge National Laboratory. It was designed to operate at 250 megawatts (thermal). The reactor occupies a footprint of (about and is tall, occupying a volume of . The reactor core itself consisted of a graphite box measuring occupying a volume of and weighing . It was penetrated horizontally through its entire length by
Enrico Fermi December. The shape of the pile was intended to be roughly spherical, but as work proceeded Fermi calculated that criticality could be achieved without finishing the entire pile as planned. This experiment was a landmark in the quest for energy, and it was typical of Fermi's approach. Every step was carefully planned, every calculation meticulously done. When the first self-sustained nuclear chain reaction was achieved, Compton made a coded phone call to James B. Conant, the chairman of the National Defense Research Committee. To continue the research where it would not pose a public health hazard, the reactor was disassembled