Oak Ridge X-10: Graphite Reactor Design, Panel 2

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,“The Graphite Reactor required a control system to shut down – stop spontaneous chain reactions or reduce the release of neutrons. The system consisted of seven control rods, each eight feet long, that could soak up neutrons to prevent fission.”

To the right is a photograph of a man at a worktable, facing a wall covered with panels filled with dials and controls. Signs to the right reads “Lethal Hazard” and “Danger, X-rays.”

Text on the middle of the panel reads,“Three steel and cadmium control rods could be vertically dropped through the reactor core by gravity to ‘scram’ or shut down the reactor. Four steel and boron rods – two moved by hydraulic pistons and two driven by electric motors – penetrated horizontally to control the power level. To start the reactor, the three vertical rods were pulled from the core to allow fission, and two rods were withdrawn partially or completely to adjust the power level. Fission created tremendous heat in the reactor core that had to be removed to avoid melting of structural parts. The reactor was cooled by air moved by huge fans. After passing through the reactor core, the cooling air was filtered, removing 99 percent of its radioactive particles, and exhausted through a 200-foot stack.”

On the left side is a drawing of the reactor with the loading face with the holes for the channels at the left. Parts of the interior are cut away showing the tubes leading from the loading face into the core and the holes on the side for experiments and the control rods.

At bottom left is a photograph of two men at one of the experiment ports. One man, in coveralls, is using tongs on a long pole to lift a small cylinder while the other man holds an object shaped like a handgun but with a large cylinder instead of a gun barrel. Text reads,“The uranium slugs were held to a maximum temperature of 536 degrees Fahrenheit; the moderator, 280 degrees Fahrenheit.”

At lower right is a photograph of a small aluminum cylinder next to a plexiglass plaque which reads, "ORNL Graphite Reactor AEC, 1943 – 1966. Dedicated as a National Historic Landmark, September 13, 1966.”