The B Reactor at the Hanford Site, near Richland, WA, was the first large-scale nuclear reactor ever built. It was a key part of the Manhattan Project, the United States’ nuclear weapons development program during World War II. It converted uranium into plutonium-239 . The B reactor was fueled with uranium, graphite moderated, and water-cooled. It is a U.S. National Historic Landmark. In July 2011 the National Park Service recommended that the B Reactor be included in the Manhattan Project National Historical Park.

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* Available as a magnet.