The reactor was used in the 1960s as part of Eisenhower's 'Atoms for Peace' campaign. It was used to recycle nuclear material to be used for fuel.
The cylinder has to be carefully lifted to protect the area from further contamination.
Officials admit the ground is radioactive, but safe for the community.
Mark French with the Department of Energy said, "We do a lot of monitoring of the groundwater here and a lot of these areas. There's nothing to drive the contamination through the soil other than precipitation. So we don't think it's any threat to the environment at this point and time."
It's taken three years to dig the reactor out of the ground.
It will be buried at the Hanford site's landfill.