Oak Ridge X-10: 1940- American Discoveries

US DEPARTMENT OF ENERGY

The X-10 Graphite Reactor is located on the secure grounds of Oak Ridge National Laboratory (ORNL). In-person visitation is only authorized via guided tours.

Text at the top of this panel reads,“Scientists at Columbia University discover that uranium-235 undergoes fission more readily than uranium-238. Only one in 140 atoms of natural uranium is a uranium-235 atom. Electromagnetic separation and gaseous diffusion processes for enriching uranium are conceived. These processes would later be used at Oak Ridge’s Y-12 Plant to supply uranium for the first atomic bomb.”

Below the text is an aerial photograph of an industrial site with a large building under construction. To the right is a bird’s eye view of a tall plant building, five or six stories high, with six smokestacks on top that tower half again that height.

Text on the lower half of the panel reads,“1941. Plutonium is discovered by Glenn Seaborg at the University of California-Berkeley. It is the first man-made element. A plutonium-239 nucleus, which fissions spontaneously, is formed when a uranium-238 nucleus absorbs a free neutron released from another nucleus undergoing fission. Like, uranium-235, plutonium-239 is usable in atomic bombs. Seaborg and his team develop a multistage chemical process to separate plutonium from uranium and concentrate and purify plutonium-239.”

At lower right is a photograph of a man in white shirt and tie leaning over an instrument box, adjusting a dial. To the left is a photograph of the same man, now in suit and tie, standing behind an apparatus on a lab table. The apparatus is about 3 feet tall and consists of a glass bulb at the top of a long glass tube held upright by clamps on a metal stand.