The B-Reactor was constructed as part of the top secret Manhattan Project to produce plutonium during World War II. The reactor succeeded in its first nuclear chain reaction in September of 1944, and became the world’s first large-scale plutonium production reactor. Plutonium produced by the B-Reactor was used in the Trinity Test, and in the bomb that was dropped on Nagasaki, Japan at the end World War II. At the height of its operations, more than 30 buildings and 20 service made up the complex, but today all that remain are the reactor building, the main smoke stack, and the river pump house.
The B-Reactor was one of 3 reactors built about 6 miles
apart from each other on the south bank of the Colombia River. Its design was based
on experiments by Dr. Enrico Fermi and tests at the X-10 graphite reactor at
Oak Ridge, TN. It was comprised of a 28 by 36-foot, 1,200 pound graphite pile
that had 2,004 aluminum process tubes running horizontally along its entire
length. These tubes contained 200 tons of uranium slugs the size of a role of
quarters. Rather than using air as a coolant like the X-10 in Tennessee, water
was pumped from the river at a rate of 75,000 gallons a minute and ran through
the tubes around the slugs.
Construction of the B-Reactor began in October of 1943 and
took only 11 months to complete. Like other reactors such as the Oak Ridge
reactor, the need for labor turned the nearby town of Hansford into a sort of
atomic boomtown with the population reaching 50,000 by the summer of 1944.
The reactor was initially shut down in 1946, but due to
increasing tensions between the United States and the Soviet Union, it was restarted
in 1948 to produce plutonium for the Cold War. Under instructions from the
Atomic Energy Commission, the B-Reactor was shut down on February 12th,
Today, what remains of the reactor has been named a National
Historic Landmark and as of 2009, it has been opened for public access with
nearly 10,000 visitors each year.