Le réacteur B du site de Hanford, près de Richland, dans l’État de Washington, a converti le minerai d’uranium naturel en plutonium. C’est un élément clé du programme de développement d’armes nucléaires pendant la Seconde Guerre mondiale. Il est classé monument historique le 19 août 2008. Il peut être visité sur réservation préalable.
The B Reactor at the Hanford Site, near Richland, Washington, was the first large-scale nuclear reactor ever built. The project was a key part of the Manhattan Project, the United States nuclear weapons development program during World War II. Its purpose was to convert natural uranium ore into plutonium-239 by the process of neutron activation, as plutonium is far less complex to process than uranium itself. The B reactor was fueled with metallic natural uranium, graphite moderated, and water-cooled. It has been designated a U.S. National Historic Landmark since August 19, 2008 and in July 2011 the National Park Service recommended that the B Reactor be included in the Manhattan Project National Historical Park commemorating the Manhattan Project. Visitors can take a tour of the reactor by advance reservation.