B Reactor

B Reactor
Name	B Reactor
Location	Hanford Site, Washington
Country	United States
Operator	Manhattan Project / United States Atomic Energy Commission
Reactor type	graphite-moderated / Uranium fuel
First criticality	1944
Decommissioned	1968

B Reactor B Reactor was the first large-scale industrial nuclear reactor built and operated in the United States as part of the Manhattan Project during World War II. Located at the Hanford Site near Richland, Washington, it produced plutonium for the Trinity test and the bombing of Nagasaki, and later entered the inventory of the United States Atomic Energy Commission and the Department of Energy. The reactor is preserved as a historic landmark associated with figures such as Leslie Groves, J. Robert Oppenheimer, and institutions like DuPont and Los Alamos National Laboratory.

History

Construction of the reactor began under direction from Leslie Groves and scientific leadership from figures including Enrico Fermi and John von Neumann, following policy decisions by the S-1 Committee and approval by President Franklin D. Roosevelt. The site selection process evaluated alternatives including Oak Ridge National Laboratory and locations in the Columbia River basin near Richland, Washington and Pasco, Washington, with DuPont chosen as prime contractor. B Reactor reached first criticality in 1944 and its operation determined plutonium production schedules that influenced deployments by USAAF planners and the Manhattan District. Postwar transition placed the facility under the United States Atomic Energy Commission and later the Department of Energy, intersecting with Cold War programs managed by Los Alamos National Laboratory, Lawrence Livermore National Laboratory, and contractor networks.

Design and Construction

Design work was guided by theoretical developments from Fermi, Leó Szilárd, and Arthur Holly Compton and engineering management by DuPont teams who coordinated with the Manhattan Project infrastructure at Oak Ridge, Tennessee and Los Alamos, New Mexico. The reactor used massive graphite blocks supplied via industrial partners similar to materials sourced by wartime suppliers and relied on water cooling drawn from the Columbia River with intake systems engineered alongside Bonneville Dam regional hydrology planning. Construction mobilized labor from Richland, Washington and involved coordination with the United States Army Corps of Engineers, wartime logistics overseen by the War Production Board, and procurement by the Ordnance Department. The resulting structure embodied wartime industrial scaling analogous to projects like the Panama Canal and the Transcontinental Railroad in national significance.

Operation and Role in the Manhattan Project

During operation, B Reactor produced weapons-grade plutonium that fed weapons design programs at Los Alamos National Laboratory and informed designs such as the Fat Man implosion device developed under scientific leads like Philip Morrison and Klaus Fuchs (later implicated in espionage cases involving Soviet Union intelligence). Reactor operations were coordinated with metallurgical and chemical separation at the Hanford Site B Plant and T Plant facilities, linking to radiochemistry work by scientists from University of Chicago and Columbia University. Outputs from B Reactor contributed directly to the Trinity test at Alamogordo, New Mexico and the strategic decisions made by Harry S. Truman and military planners in 1945. Postwar, B Reactor operations supported research partnerships with national laboratories including Argonne National Laboratory and informed reactor programs at institutions such as Oak Ridge National Laboratory.

Technical Specifications

B Reactor was a graphite-moderated, water-cooled, horizontal-channel production reactor using natural uranium fuel encased in aluminum and arranged within graphite blocks to form a large lattice, a configuration influenced by experiments at Chicago Pile-1. The core contained thousands of graphite blocks and fuel channels with control rods managed by electromechanical drives designed by DuPont engineers and instrumentation developed by teams from General Electric and Westinghouse. Thermal power and neutron flux characteristics were tuned to maximize plutonium-239 production while managing xenon poisoning phenomena observed in early reactors, a problem addressed through operational adjustments that drew on reactor physics from Los Alamos National Laboratory and theory by Hans Bethe. Cooling water from the Columbia River carried heat to exchange systems sized by wartime industrial standards and monitored under safety regimes later formalized by the Nuclear Regulatory Commission predecessors in the United States Atomic Energy Commission.

Decommissioning and Preservation

After shifts in production needs and aging systems, B Reactor ceased full-scale production and was placed into standby and later decommissioned under programs managed by the United States Department of Energy. Decontamination, surveillance, and maintenance efforts involved contractor consortia similar to those at other legacy sites like Rocky Flats Plant and Savannah River Site, and policies from the Atomic Energy Act of 1954 guided regulatory frameworks. Recognition of B Reactor's historic significance led to designation as a National Historic Landmark and inclusion in preservation initiatives that involved partnerships between the Department of Energy, National Park Service, Washington State agencies, and local stakeholders from Benton County, Washington and the city of Richland, Washington. Public tours, interpretive exhibits, and archival collections link B Reactor to scholarship at institutions such as Smithsonian Institution and university archives.

Cultural and Historical Impact

B Reactor occupies a central place in narratives about World War II, the dawn of the Atomic Age, and Cold War nuclear policy debates that involved policymakers like Harry S. Truman and strategists within the United States Department of Defense. It features in historical studies concerning ethics of science involving figures such as J. Robert Oppenheimer and controversies like the Gouzenko Affair and espionage cases impacting Manhattan Project security. B Reactor's story informs public history, museum practice, and heritage preservation debates similar to those surrounding the Industrial Workers of the World heritage and site interpretation at Ellis Island. Scholarly work by historians at Harvard University, University of California, Berkeley, and University of Chicago continues to situate the reactor within broader discussions of technology, policy, and memory.

Category:Hanford Site