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J.R. Oppenheimer and General Groves

F Reactor Plutonium Production Complex at Hanford, 1945HANFORD BECOMES OPERATIONAL
(Hanford Engineer Works, 1943-1944)
Events > The Plutonium Path to the Bomb, 1942-1944

The plutonium production facilities at the Hanford Engineer Works took shape with the same wartime urgency as did the uranium facilities at Oak Ridge.  In February 1943, Colonel Matthias returned to the location he had helped select the previous December and set up a temporary headquarters.  In late March, Matthias received his assignment.  The three water-cooled production reactor (piles), designated by the letters B, D, and F, would be built about six miles apart on the south bank of the Columbia River.  The four chemical separation plants would be built in pairs at two sites nearly ten miles south of the piles.  A facility to produce slugs and perform tests would be approximately twenty miles southeast of the separation plants near Richland.  Temporary quarters for construction workers would be put up at the Hanford town site, while permanent facilities for other personnel would be located down the road in Richland, safely removed from the production and separation plants.  Life at Hanford would soon come to resemble that of the other "atomic boomtowns" of the Manhattan Project, Los Alamos and Oak Ridge.

Mess Hall, Hanford construction camp, 1944Ground-breaking for the water-cooling plant for the B Reactor, the westernmost of the three, took place on August 27, 1943.  Construction also began that summer on the two chemical separation locations (200-West and 200-East).  The facilities there were to be massive, scaled-up versions of those associated with X-10 at Oak Ridge, each containing separation and concentration buildings in addition to ventilation (to eliminate radioactive and poisonous gases) and waste storage areas.  Labor shortages and the lack of final blueprints, however, soon forced DuPont to stop work on the 200 areas and concentrate on the construction of support facilities in the B Reactor area (100-B).  As a result, the 1943 progress on chemical separation was limited to the digging of two very large holes in the ground.

Construction of B Reactor, Hanford Not until October 10 did DuPont engineers drive the first stakes marking the location of the B-Reactor pile building.  The area immediately under the pile was excavated and carefully load-tested.  Once the foundations were fixed, work gangs began to lay the first of 390 tons of structural steel, 17,400 cubic yards of concrete, 50,000 concrete blocks, and 71,000 concrete bricks that went into the pile building.  By early 1944, a windowless concrete monolith towered 120 feet above the desert.  Assembly of the pile itself began in February.  The cast-iron base and the thermal and biological shields around the pile were completed by mid-May.  It took another month to lay the graphite blocks within the shield and install the top shield and two months to wire and pipe the pile and connect it to various monitoring and control devices.  By July 1944, not only was the B Reactor nearing completion, but the second (D) reactor was about halfway finished as well.  Work on the third (F) reactor had not yet begun.  To test several new technologies, a smaller test pile was constructed at Hanford and began operations in March of 1944. 

U Plant chemical separation building at HanfordIn January 1944, workers laid the foundations for the first chemical separation building, T Plant located in 200-West.  Both the T Plant and its sister facility in 200-West, the U Plant, were completed by October.  (U Plant was used only for training during the Manhattan Project.)  The separation building in 200-East, B Plant, was completed in February 1945. The second facility planned for 200-East was canceled.  Nicknamed Queen Marys by the workers who built them, the separation buildings were awesome canyon-like structures 800 feet long, 65 feet wide, and 80 feet high containing forty process pools.  The interior had an eerie quality as operators behind seven feet of concrete shielding manipulated remote control equipment  by looking through television monitors and periscopes from an upper gallery.  Even with massive concrete lids on the process pools, precautions against radiation exposure were necessary and influenced all aspects of plant design. 

Face of B Reactor during construction, HanfordGiven how new all of these technological systems were, no one knew whether they would work as anticipated.  Excitement mounted at Hanford as the date for the first operation of a plutonium production reactor approached.  On September 13, 1944, Enrico Fermi placed the first slug into the pile at B Reactor.  Final checks on the pile had been uneventful.  The scientists could only hope they were accurate, since once the reactor was operational the intense radioactivity would make maintenance of many components impossible.  Loading slugs and taking measurements lasted two weeks.  From just after midnight until approximately 3:00 a.m. on September 27, the pile ran without incident at a power level higher than any previous fission chain reaction (though only at a fraction of design capacity).  The operators were elated, but their excitement turned to astonishment when the power level began falling after three hours.  It fell continuously until the pile ceased operating entirely on the evening of the 28th.  By the next morning, the reaction began again, reached the previous day's level, then dropped.

Front face of F Reactor, Hanford, February 1945Hanford scientists were at a loss to explain the pile's failure to maintain a chain reaction. Only the foresight of DuPont's engineers made it possible to resolve the crisis.  The cause of the strange phenomenon proved to be xenon poisoning, wherein xenon (a fission by-product) gradually built-up and absorbed neutrons that were needed to sustain the chain reaction.  With shutdown, the xenon decayed, neutron flow resumed, and the pile started up again.  Fortuitously, despite the objections of some scientists who complained of DuPont's excessive caution, the company had installed a large number of extra tubes. This design feature meant that the pile in B Reactor could be expanded to reach a power level sufficient to overwhelm the xenon poisoning.  Success was achieved when the first irradiated slugs were discharged from B Reactor on Christmas Day, 1944.  The irradiated slugs, after several weeks of storage, went to the chemical separation and concentration facilities.  By the end of January 1945, the highly purified plutonium underwent further concentration in the completed chemical isolation building, where remaining impurities were removed successfully.  Los Alamos received its first plutonium from Hanford on February 2.  While it was still by no means clear that enough plutonium could be produced for use in bombs by the war's end, Hanford was by early 1945 in operation.  Only two years had passed since Matthias first set up his temporary headquarters on the banks of the Columbia River.

To view the next "event" of the Manhattan Project, proceed to "1942-1945: Bringing It All Together."


Sources and notes for this page.

The text for this page was adapted from, and portions were taken directly from the Office of History and Heritage Resources publications: F. G. Gosling, The Manhattan Project: Making the Atomic Bomb (DOE/MA-0001; Washington: History Division, Department of Energy, January 1999), 32-35, 41-42, and Richard G. Hewlett and Oscar E. Anderson, Jr., The New World, 1939-1946: Volume I, A History of the United States Atomic Energy Commission (Washington: U.S. Atomic Energy Commission, 1972), 212-22, 304-10.  See also Vincent C. Jones, Manhattan: The Army and the Atomic Bomb, United States Army in World War II (Washington: Center of Military History, United States Army, 1988), 218.  Click here for more information on the aerial photograph of Hanford.  The photograph of the mess hall is reproduced from the Department of Energy report Linking Legacies: Connecting the Cold War Nuclear Weapons Production Processes to their Environmental Consequences (Washington: Center for Environmental Management Information, Department of Energy, January 1997), 25. The photograph of B Reactor under construction is courtesy the Hanford Site. The photograph of several Queen Marys is courtesy Richland Operations, DOE -- Robley Johnson or his assistant, photographer; it is reprinted in Peter Bacon Hales, Atomic Spaces: Living on the Manhattan Project (Urbana and Chicago: University of Illinois Press, 1997), 133.  The photograph of the face of B Reactor is reproduced from the History Office publication: The Signature Facilities of the Manhattan Project (Washington: History Division, Department of Energy, 2001), 7.  The photograph of the front face of F Reactor was taken by Robley Johnson; it is courtesy the Department of Energy (DOE), and it is reprinted in Rachel Fermi and Esther Samra, Picturing the Bomb: Photographs from the Secret World of the Manhattan Project (New York: Harry N. Abrams, Inc., Publishers, 1995), 71.

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