Oak Ridge X-10: Graphite Reactor Design, Panel 1

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 had a maximum power of 4,000 kilowatts. The highest power could be safely reached only on cold days because outside air was used to cool the reactor.”

To the right is a photograph with a bird’s eye view of the reactor building, a five-story tall, square structure with lower wings along each side. Two tall smokestacks rise in the background.

Below that text reads,“The fuel was natural uranium – 99.3 percent uranium-238 and 0.7 percent uranium-235 – contained in gas-tight cylindrical aluminum jackets.”

To the left of the text is an image of uranium’s entry in a periodic table of the elements. Below that text reads,“Only 800 of 1,248 horizontal fuel channels contained one by four inch fuel slugs. These were hand-inserted and centered in the moderator with long rods. With 24 to 54 slugs per channel, the reactor usually contained 54 tons of fuel.”

Below the text is a photograph of two operators at the loading face holding a long metal rod which extends into one of the channels. To the right more text reads,“Spent fuel slugs were pushed from the fuel channels into a canal filled with water 20 feet deep. The water and seven feet of concrete surrounding the reactor prevented the escape of radiation.”

Above that text is a photograph of several workers, three men and one woman, manipulating a rectangular lead shield next to one of the experimental faces.

At lower left text reads,“A 24-foot cube of graphite made of stacked blocks formed a moderator to slow the neutrons to a speed at which uranium nuclei could readily absorb them to cause fission.”

At lower right is an illustration of the graphite moderator with one corner cut away to show the rows of stacked blocks. Small figures of men are placed on a metal gantry at the back of the moderator and sitting at a control panel on the floor level at lower left.