The third of Hanford’s three original nuclear reactors is the F Reactor. F is the reactor located closest to present day Richland.
F Reactor became operational in February of 1945 and ran for more than twenty years until it was shut down in June of 1965. Originally, the F Reactor used about 35,000 gallons of water per minute to cool the reactor during operations. However, as the facility expanded and became more efficient, F needed almost 70,000 gallons of water per minute to keep the heat generated by the nuclear chain reaction under control.
The F Reactor was cocooned in 2003, making it the third Hanford reactor to have its core encased in a concrete shell. In 2008, radiation technicians entered F for the first time to examine the cocoon and confirm that no radiation was leaking out of the cocoon and that nothing was getting inside the cocoon either. With the exception of seeing evidence of some mice and insects, the cocoon appeared to be in perfect condition. The next scheduled entry into the F Reactor is planned for 2015.