Site A / Plot M: The Buried Remains of The World’s First Nuclear Reactor

Located within the Palos Forest Preserve, approximately 20 miles southwest of downtown Chicago, in an area named the Red Gate Woods, are two spots designated Site A and Plot M. Site A is 19 acre in size and contains the buried remains of the world’s first nuclear reactor, while the 150 feet by 140 feet area known as Plot M is a radioactive waste dump. The world's first nuclear reactor designated Chicago Pile-1 (CP-1) was built at the University of Chicago, under extreme secrecy as part of the Allied effort to build the atomic bomb during the Second World War. The reactor was assembled in November 1942, under the watchful eyes of such prominent physicists such as Enrico Fermi and Leo Szilard, the discoverer of the chain reaction. On a cold December morning in 1942, less than a month later, the first man-made self-sustaining nuclear chain reaction was initiated. There was no big bang, but this humble beginning was the true dawn of the nuclear age. Marker at Plot M. Photo credit: Federal Government of the United States The reactor in Chicago, described by Fermi as "a crude pile of black bricks and wooden timbers", consisted of 360 metric tons of graphite, used as a neutron moderator to slow down neutrons, and was fueled by 5.4 tons of uranium metal and 45 tons of uranium oxide. Because the reactor was designed to operate at very low power, it had no radiation shield nor any cooling system. Nevertheless, it was a radiation hazard to everyone in the vicinity. So shortly afterwards, the reactor was dismantled and moved to a forest outside Chicago and rebuilt at an area now called Red Gate Woods. The reactor was renamed Chicago Pile-2. Chicago Pile-2 (CP-2) was bigger and more powerful, running at a few kilowatts, and it had a radiation shield. CP-2 was joined by another reactor Chicago Pile-3. Both reactors operated for ten years before they outlived their usefulness, and was shutdown in 1954.