B Reactor

B Reactor at the Hanford Site near Richland, Washington, was the world’s first large-scale nuclear reactor and a major advance in the Manhattan Project. Achieving criticality in 1944, it converted natural uranium into plutonium-239 for nuclear weapons, including material used in the Trinity test and the Fat Man bomb. Designed largely by DuPont and based on earlier experimental work, it was a graphite-moderated, water-cooled production reactor that also pioneered large-scale water cooling and confronted the first xenon poisoning problem. After nearly 24 years of operation, it was shut down in 1968 and preserved as a rare surviving artifact of the wartime atomic program.

Washington · United States