B Reactor (Hanford Site)

B Reactor (Hanford Site)
Name	B Reactor
Country	United States
Location	Hanford Site, Richland, Washington
Operator	DuPont
Owner	United States Department of Energy
Type	Graphite-moderated, water-cooled
Status	Decommissioned, preserved
Construction began	1943
Commissioned	1944
Decommissioned	1968

B Reactor (Hanford Site) is the first large-scale plutonium production reactor built and operated in the United States. Conceived during World War II and constructed at the Hanford Site in Washington, it produced plutonium used in the Trinity test and the Fat Man design, shaping Cold War nuclear policy. The reactor is a milestone in nuclear engineering, Manhattan Project logistics, and 20th-century industrial mobilization.

History

The reactor emerged from decisions by Manhattan Project leaders including James B. Conant, Vannevar Bush, and Leslie Groves, with scientific guidance from Enrico Fermi and Richard C. Tolman. Site selection at Hanford Site followed surveys influenced by General Leslie Groves and recommendations from the United States Army Corps of Engineers. Construction was awarded to DuPont under wartime contract, connecting to broader industrial efforts exemplified by Oak Ridge National Laboratory and the Los Alamos Laboratory. Post-war transitions involved the Atomic Energy Commission and later the United States Department of Energy. Cold War expansions tied B Reactor’s output to nuclear weapons programs overseen by Sandia National Laboratories and Lawrence Livermore National Laboratory.

Design and Construction

Design work combined inputs from Metallurgical Laboratory scientists and engineers from DuPont, drawing on research at University of Chicago and tests at CP-1. The reactor used a large graphite moderator stack and metallic fuel elements within an aluminum-clad matrix, cooled by high-volume water flow through the Columbia River. Construction in 1943–1944 required rapid mobilization of labor, heavy industry, and rail infrastructure connecting to Richland, Washington and Portland, Oregon. Air handling, shielding, and remote handling systems reflected wartime innovation parallel to projects at Hanford Site B reactor-era facilities at Hanford Site D reactor and Hanford Site F reactor.

Operation and Role in the Manhattan Project

B Reactor achieved first criticality in 1944 and produced the plutonium used in the Trinity test and the Fat Man bomb, linking it to Los Alamos National Laboratory weapons design and Robert Oppenheimer. Daily operations were staffed by DuPont technicians, U.S. Army personnel, and a growing scientific cadre that included chemists from Argonne National Laboratory and metallurgists from Metallurgical Laboratory. The reactor’s output shaped strategic decisions at Potsdam Conference-era deliberations and influenced policy by figures like Harry S. Truman. Coordination with separation facilities at Hanford Site B Plant and chemical engineering teams was essential for plutonium extraction used by Los Alamos Laboratory.

Decommissioning and Preservation

Operations wound down through the postwar and Cold War decades, with final shutdown in 1968 under the United States Atomic Energy Commission. Subsequent decommissioning actions were managed by successors including the U.S. Department of Energy and contractors who implemented radiological stabilization similar to programs at Three Mile Island and Oak Ridge Reservation. Preservation efforts involved the National Park Service, United States Department of Energy, and advocacy by organizations such as the Atomic Heritage Foundation; B Reactor was designated a National Historic Landmark and opened for public tours as part of heritage initiatives alongside sites like Manhattan Project National Historical Park.

Reactor Technology and Engineering

B Reactor’s technology combined a large graphite moderator, aluminum-clad uranium slugs, and water cooling—an approach informed by experiments at Metallurgical Laboratory and designs by Enrico Fermi. Reactor physics concepts including neutron moderation, critical mass, and reactivity control were central to operations, paralleling research at Chalk River Laboratories and later commercial designs at Westinghouse Electric Corporation. Engineering challenges included corrosion, xenon poisoning phenomena discovered in reactor operations, and remote handling of radioactive fuel similar to technologies developed at Hanford Site chemical separation plants.

Environmental and Health Impacts

Routine operations and chemical separations at Hanford released radionuclides and chemical contaminants to soils, groundwater, and the Columbia River, prompting environmental management by the U.S. Environmental Protection Agency and DOE cleanup programs comparable to remediation at Soviet nuclear sites and Sellafield. Worker health studies involved coordination with National Institute for Occupational Safety and Health and epidemiological reviews by medical centers. Decontamination, waste retrieval, and vitrification efforts reflect long-term stewardship challenges shared with sites managed by DOE Office of Environmental Management.

Cultural and Historical Significance

B Reactor symbolizes intersections among World War II science, industrial mobilization, and Cold War weapons policy, resonating in narratives about figures like J. Robert Oppenheimer, Leslie Groves, and Enrico Fermi. It features in public history via the Manhattan Project National Historical Park, exhibits curated by the National Park Service, and scholarship from historians at institutions such as Harvard University and Los Alamos National Laboratory. The site prompts ethical reflection seen in discussions involving the Trinity decision, public memory studies, and outreach by organizations including the Atomic Heritage Foundation.

Category:Nuclear reactors in the United States Category:History of Washington (state)