Hanford Site

Nuclear reactors line the riverbank at the Hanford Site along the Columbia River in January 1960. The N Reactor is in the foreground, with the twin KE and KW Reactors in the immediate background. The historic B Reactor, the world's first plutonium production reactor, is visible in the distance.

The Hanford Site is a mostly decommissioned nuclear production complex on the Columbia River in the U.S. state of Washington, operated by the United States federal government. The site has been known by many names, including Hanford Works, Hanford Engineer Works, Hanford Nuclear Reservation or HNR, and the Hanford Project. Established in 1943 as part of the Manhattan Project in the town of Hanford in south-central Washington, the site was home to the B Reactor, the first full-scale plutonium production reactor in the world.^[1] Plutonium manufactured at the site was used in the first nuclear bomb, tested at the Trinity site, and in Fat Man, the bomb detonated over Nagasaki, Japan.

During the Cold War, the project was expanded to include nine nuclear reactors and five large plutonium processing complexes, which produced plutonium for most of the 60,000 weapons in the U.S. nuclear arsenal.^[2][3] Nuclear technology developed rapidly during this period, and Hanford scientists produced many notable technological achievements. Many of the early safety procedures and waste disposal practices were inadequate, and government documents have since confirmed that Hanford's operations released significant amounts of radioactive materials into the air and the Columbia River, which threatened the health of residents and ecosystems.^[4]

The weapons production reactors were decommissioned at the end of the Cold War, but the manufacturing process left behind 53 million U.S. gallons (204,000 m³) of high-level radioactive waste that remains at the site.^[5] This represents two-thirds of the nation's high-level radioactive waste by volume.^[6] Today, Hanford is the most contaminated nuclear site in the United States^[7][8] and is the focus of the nation's largest environmental cleanup.^[2] While most of the current activity at the site is related to the cleanup project, Hanford also hosts a commercial nuclear power plant, the Columbia Generating Station, and various centers for scientific research and development, such as the Pacific Northwest National Laboratory and the LIGO Hanford Observatory.

Geography

A map shows the main areas of the Hanford Site, as well as the buffer zone that was turned over to the Hanford Reach National Monument in 2000. (See also this virtual tour of the site.)

The Hanford Site occupies 586 square miles (1,518 km²) in Benton County, Washington (centered on ), roughly equivalent to a third of the total area of Rhode Island.^[2] This land is currently uninhabited and is closed to the general public. It is a desert environment receiving under 10 inches of annual precipitation, covered mostly by shrub-steppe vegetation. The Columbia River flows along the site for approximately 50 miles (80 km), forming its northern and eastern boundary.^[9] The original site was 670 square miles (1,740 km²) and included buffer areas across the river in Grant and Franklin counties.^[10] Some of this land has been returned to private use and is now covered with orchards and irrigated fields. In 2000, large portions of the site were turned over to the Hanford Reach National Monument.^[11] The site is divided by function into three main areas. The nuclear reactors were located along the river in an area designated as the 100 Area; the chemical separations complexes were located inland in the Central Plateau, designated as the 200 Area; and various support facilities were located in the southeast corner of the site, designated as the 300 Area.^[12]

The site is bordered on the southeast by the Tri-Cities, a metropolitan area composed of Richland, Kennewick, Pasco, and smaller communities, and home to over 230,000 residents. Hanford is a primary economic base for these cities.^[13]

Early history

The confluence of the Yakima, Snake, and Columbia rivers has been a meeting place for native peoples for centuries. The archaeological record of Native American habitation of this area stretches back over ten thousand years. Tribes and nations including the Yakama, Nez Perce, and Umatilla used the area for hunting, fishing, and gathering plant foods.^[14] Hanford archaeologists have identified numerous Native American sites, including "pit house villages, open campsites, fishing sites, hunting/kill sites, game drive complexes, quarries, and spirit quest sites",^[10] and two archaeological sites were listed on the National Register of Historic Places in 1976.^[15] Native American use of the area continued into the 20th century, even as the tribes were relocated to reservations. The Wanapum people were never forced onto a reservation, and they lived along the Columbia River in the Priest Rapids Valley until 1943.^[10] Euro-Americans began to settle the region in the 1860s, initially along the Columbia River south of Priest Rapids. They established farms and orchards supported by small-scale irrigation projects and railroad transportation, with small town centers at Hanford, White Bluffs, and Richland.^[16]

Manhattan Project

During World War II, the Uranium Committee of the federal Office of Scientific Research and Development (OSRD) sponsored an intensive research project on plutonium. The research contract was awarded to scientists at the University of Chicago Metallurgical Laboratory (Met Lab). At the time, plutonium was a rare element that had only recently been isolated in a University of California laboratory. The Met Lab researchers worked on producing chain-reacting "piles" of uranium to convert it to plutonium and finding ways to separate plutonium from uranium. The program was accelerated in 1942, as the United States government became concerned that scientists in Nazi Germany were developing a nuclear weapons program.^[17]

Site selection

Hanford High School, shown before residents were displaced by the creation of the Hanford Site

Hanford High after abandonment

In September 1942, the Army Corps of Engineers placed the newly formed Manhattan Project under the command of General Leslie R. Groves, charging him with the construction of industrial-size plants for manufacturing plutonium and uranium.^[10] Groves recruited the DuPont Company to be the prime contractor for the construction of the plutonium production complex. DuPont recommended that it be located far away from the existing uranium production facility at Oak Ridge, Tennessee. The ideal site was described by these criteria:^[18]

• A large and remote tract of land
• A "hazardous manufacturing area" of at least 12 by 16 miles (19 by 26 km)
• Space for laboratory facilities at least 8 miles (13 km) from the nearest reactor or separations plant
• No towns of more than 1,000 people closer than 20 miles (32 km) from the hazardous rectangle
• No main highway, railway, or employee village closer than 10 miles (16 km) from the hazardous rectangle
• A clean and abundant water supply
• A large electric power supply
• Ground that could bear heavy loads.

In December 1942, Groves dispatched his assistant Colonel Franklin T. Matthias and DuPont engineers to scout potential sites. Matthias reported that Hanford was "ideal in virtually all respects," except for the farming towns of White Bluffs and Hanford.^[19] General Groves visited the site in January and established the Hanford Engineer Works, codenamed "Site W". The federal government quickly acquired the land under its eminent domain authority and relocated some 1,500 residents of Hanford, White Bluffs, and nearby settlements, as well as the Wanapum and other tribes using the area.^[10]

Construction begins

B-Reactor construction (1944)

The Hanford Engineer Works (HEW) broke ground in March 1943 and immediately launched a massive and technically challenging construction project.^[20] Nearly 50,000 workers lived in a construction camp near the old Hanford townsite, while administrators and engineers lived in the government town established at Richland Village.^[21] Construction of the nuclear facilities proceeded rapidly. Before the end of the war in August 1945, the HEW built 554 buildings at Hanford, including three nuclear reactors (105-B, 105-D, and 105-F) and three plutonium processing canyons (221-T, 221-B, and 221-U), each 250 meters (820 ft) long.

To receive the radioactive wastes from the chemical separations process, the HEW built "tank farms" consisting of 64 single-shell underground waste tanks (241-B, 241-C, 241-T, and 241-U).^[22] The project required 386 miles (621 km) of roads, 158 miles (254 km) of railway, and four electrical substations. The HEW used 780,000 cubic yards (600,000 m³) of concrete and 40,000 short tons (36,000 t) of structural steel and consumed $230 million between 1943 and 1946.^[23]

Plutonium production

The B-Reactor (105-B) at Hanford was the first large-scale plutonium production reactor in the world. It was designed and built by DuPont based on an experimental design by Enrico Fermi, and originally operated at 250 megawatts. The reactor was graphite moderated and water cooled. It consisted of a 28-by-36-foot (8.5 by 11 m), 1,200-short-ton (1,100 t) graphite cylinder lying on its side, penetrated through its entire length horizontally by 2,004 aluminium tubes.^[24] Two hundred short tons (180 t) of uranium slugs the size of rolls of U.S. quarters and sealed in aluminium cans went into the tubes.^[24] A roll of quarters is about 1 inch (2.5 cm) by 2.9 inches (7.4 cm).^[25] Cooling water was pumped through the aluminium tubes around the uranium slugs at the rate of 30,000 US gallons per minute (2,000 liters/sec).^[24]

Workers standing on the elevator at the front face of B Reactor.

Construction on the B-Reactor began in August 1943 and was completed just over a year later, on September 13, 1944. The reactor went critical in late September and, after overcoming nuclear poisoning, produced its first plutonium on November 6, 1944.^[26] Plutonium was produced in the Hanford reactors when a uranium-238 atom in a fuel slug absorbed a neutron to form uranium-239. U-239 rapidly undergoes beta decay to form neptunium-239, which rapidly undergoes a second beta decay to form plutonium-239. The irradiated fuel slugs were transported by rail to three huge remotely operated chemical separation plants called "canyons" that were located about 10 miles (16 km) away. A series of chemical processing steps separated the small amount of plutonium that was produced from the remaining uranium and the fission waste products. This first batch of plutonium was refined in the 221-T plant from December 26, 1944, to February 2, 1945, and delivered to the Los Alamos laboratory in New Mexico on February 5, 1945.^[27]

Two identical reactors, the D-Reactor and the F-reactor, came online in December 1944 and February 1945, respectively. By April 1945, shipments of plutonium were headed to Los Alamos every five days, and Hanford soon provided enough material for the bombs tested at Trinity and dropped over Nagasaki.^[28] Throughout this period, the Manhattan Project maintained a top secret classification. Until news arrived of the bomb dropped on Hiroshima, fewer than one percent of Hanford's workers knew they were working on a nuclear weapons project.^[29] General Groves noted in his memoirs that "We made certain that each member of the project thoroughly understood his part in the total effort; that, and nothing more."^[30]

Technological innovations

In the short time frame of the Manhattan Project, Hanford engineers produced many significant technological advances. As no one had ever built an industrial-scale nuclear reactor before, scientists were unsure how much heat would be generated by fission during normal operations. Seeking the greatest possible production while maintaining an adequate safety margin, DuPont engineers installed ammonia-based refrigeration systems with the D and F reactors to further chill the river water before its use as reactor coolant.^[31]

Another difficulty the engineers struggled with was how to deal with radioactive contamination. Once the canyons began processing irradiated slugs, the machinery would become so radioactive that it would be unsafe for humans ever to come in contact with it. The engineers therefore had to devise methods to allow for the replacement of any component via remote control. They came up with a modular cell concept, which allowed major components to be removed and replaced by an operator sitting in a heavily shielded overhead crane. This method required early practical application of two technologies that later gained widespread use: Teflon, used as a gasket material, and closed-circuit television, used to give the crane operator a better view of the process.^[32]

Cold War expansion

Decommissioning the D-Reactor

In September 1946, the General Electric Company assumed management of the Hanford Works under the supervision of the newly created Atomic Energy Commission. As the Cold War began, the United States faced a new strategic threat in the rise of the Soviet nuclear weapons program. In August 1947, the Hanford Works announced funding for the construction of two new weapons reactors and research leading to the development of a new chemical separations process. With this announcement, Hanford entered a new phase of expansion.^[33]

By 1963, the Hanford Site was home to nine nuclear reactors along the Columbia River, five reprocessing plants on the central plateau, and more than 900 support buildings and radiological laboratories around the site.^[2] Extensive modifications and upgrades were made to the original three World War II reactors, and a total of 177 underground waste tanks were built.^[2] Hanford was at its peak production from 1956 to 1965. Over the entire 40 years of operations, the site produced about 63 short tons (57 t) of plutonium, supplying the majority of the 60,000 weapons in the U.S. arsenal.^[2][3]

Decommissioning

Most of the reactors were shut down between 1964 and 1971, with an average individual life span of 22 years. The last reactor, the N-reactor, continued to operate as a dual-purpose reactor, being both a power reactor used to feed the civilian electrical grid via the Washington Public Power Supply System (WPPSS) and a plutonium production reactor for nuclear weapons. The N-Reactor operated until 1987. Since then, most of the Hanford reactors have been entombed ("cocooned") to allow the radioactive materials to decay, and the surrounding structures have been removed and buried.^[34] The B-Reactor has not been cocooned and is accessible to the public on occasional guided tours. It was listed on the National Register of Historic Places in 1992,^[35] and some historians advocate converting it into a museum.^[36][37] B reactor was designated a National Historic Landmark by the National Park Service on August 19, 2008.^[38][39]

Later operations

Highway sign on a road entering the Hanford Site

The United States Department of Energy assumed control of the Hanford Site in 1977. Although uranium enrichment and plutonium breeding were slowly phased out, the nuclear legacy left an indelible mark on the Tri-Cities. Since World War II, the area had developed from a small farming community to a booming "Atomic Frontier" to a powerhouse of the nuclear-industrial complex.^[41] Decades of federal investment created a community of highly skilled scientists and engineers. As a result of this concentration of specialized skills, the Hanford Site was able to diversify its operations to include scientific research, test facilities, and commercial nuclear power production.

Some of the facilities currently located at the Hanford Site:

• The Pacific Northwest National Laboratory, owned by the Department of Energy and operated by Battelle Memorial Institute
• The Fast Flux Test Facility (FFTF), a national research facility in operation from 1980 to 1992 (in cold standby as of 2007^[update])
• LIGO's Hanford Observatory, an interferometer searching for gravitational waves
• Columbia Generating Station, a commercial nuclear power plant operated by Energy Northwest.

The Department of Energy and its contractors offer tours of the site. Sixty public tours, each five hours long, are planned for 2009. The tours are free, require advanced reservation via the department's web site, and are limited to U.S. citizens at least 18 years of age.^[42]

Environmental concerns

The Hanford Reach of the Columbia River, where radioactivity was released from 1944 to 1971

A huge volume of water from the Columbia River was required to dissipate the heat produced by Hanford's nuclear reactors. From 1944 to 1971, pump systems drew cooling water from the river and, after treating this water for use by the reactors, returned it to the river. Before being released back into the river, the used water was held in large tanks known as retention basins for up to six hours. Longer-lived isotopes were not affected by this retention, and several terabecquerels entered the river every day. These releases were kept secret by the federal government.^[4] Radiation was later measured downstream as far west as the Washington and Oregon coasts.^[43]

The plutonium separation process also resulted in the release of radioactive isotopes into the air, which were carried by the wind throughout southeastern Washington and into parts of Idaho, Montana, Oregon, and British Columbia.^[4] Downwinders were exposed to radionuclides, particularly iodine-131, with the heaviest releases during the period from 1945 to 1951. These radionuclides filtered into the food chain via contaminated fields where dairy cows grazed; hazardous fallout was ingested by communities who consumed the radioactive food and drank the milk. Most of these airborne releases were a part of Hanford's routine operations, while a few of the larger releases occurred in isolated incidents. In 1949, an intentional release known as the "Green Run" released 8,000 curies of iodine-131 over two days.^[44] Another source of contaminated food came from Columbia River fish, an impact felt disproportionately by Native American communities who depended on the river for their customary diets.^[4] A U.S. government report released in 1992 estimated that 685,000 curies of radioactive iodine-131 had been released into the river and air from the Hanford site between 1944 and 1947.^[45]

Salmon spawning in the Hanford Reach near the H-Reactor

Beginning in the 1960s, scientists with the U.S. Public Health Service published reports about radioactivity released from Hanford, and there were protests from the health departments of Oregon and Washington. By February 1986, mounting citizen pressure forced the Department of Energy to release to the public 19,000 pages of previously unavailable historical documents about Hanford’s operations.^[4] The Washington State Department of Health collaborated with the citizen-led Hanford Health Information Network (HHIN) to publicize data about the health effects of Hanford’s operations. HHIN reports concluded that residents who lived downwind from Hanford or who used the Columbia River downstream were exposed to elevated doses of radiation that placed them at increased risk for various cancers and other diseases.^[4] A mass tort lawsuit brought by two thousand Hanford downwinders against the federal government has been in the court system for many years.^[46] The first six plaintiffs went to trial in 2005, in a bellwether trial to test the legal issues applying to the remaining plaintiffs in the suit.^[47]

Cleanup era

Image of the surface of waste found inside double-shell tank 101-SY at the Hanford Site, April 1989

On June 25, 1988, the Hanford site was divided into four areas and proposed for inclusion on the National Priorities List.^[48] On May 15, 1989, the Washington Department of Ecology, the federal Environmental Protection Agency, and the Department of Energy entered into the Tri-Party Agreement, which provides a legal framework for environmental remediation at Hanford.^[8] The agencies are currently engaged in the world's largest environmental cleanup, with many challenges to be resolved in the face of overlapping technical, political, regulatory, and cultural interests. The cleanup effort is focused on three outcomes: restoring the Columbia River corridor for other uses, converting the central plateau to long-term waste treatment and storage, and preparing for the future.^[49] The cleanup effort is managed by the Department of Energy under the oversight of the two regulatory agencies. A citizen-led Hanford Advisory Board provides recommendations from community stakeholders, including local and state governments, regional environmental organizations, business interests, and Native American tribes.^[50] In recent years, the federal government has spent about $2 billion annually on the Hanford project.^[51] About 11,000 workers are on site to consolidate, clean up, and mitigate waste, contaminated buildings, and contaminated soil.^[5] Originally scheduled to be complete within thirty years, the cleanup was less than half finished by 2008.^[51] Of the four areas that were formally listed as Superfund sites on October 4, 1989, only one has been removed from the list following cleanup.^[52]

Spent nuclear fuel stored underwater and uncapped in Hanford's K-East Basin

While major releases of radioactive material ended with the reactor shutdown in the 1970s, parts of the Hanford Site remain heavily contaminated. Many of the most dangerous wastes are contained, but there are concerns about contaminated groundwater headed toward the Columbia River. There are also continued concerns about workers' health and safety.^[51]

The most significant challenge at Hanford is stabilizing the 53 million U.S. gallons (204,000 m³) of high-level radioactive waste stored in 177 underground tanks. About a third of these tanks have leaked waste into the soil and groundwater.^[53] As of 2008^[update], most of the liquid waste has been transferred to more secure double-shelled tanks; however, 2.8 million U.S. gallons (10,600 m³) of liquid waste, together with 27 million U.S. gallons (100,000 m³) of salt cake and sludge, remains in the single-shelled tanks.^[5] That waste was originally scheduled to be removed by 2018. The revised deadline is 2040.^[51] Nearby aquifers contain an estimated 270 billion U.S. gallons (1 billion m³) of contaminated groundwater as a result of the leaks.^[54] As of 2008^[update], 1 million U.S. gallons (4,000 m³) of highly radioactive waste is traveling through the groundwater toward the Columbia River. This waste is expected to reach the river in 12 to 50 years if cleanup does not proceed on schedule.^[5] The site also includes 25 million cubic feet (710,000 m³) of solid radioactive waste.^[54]

Grand opening of the Environmental Restoration Disposal Facility (ERDF)

Under the Tri-Party Agreement, lower-level hazardous wastes are buried in huge lined pits that will be sealed and monitored with sophisticated instruments for many years. Disposal of plutonium and other high-level wastes is a more difficult problem that continues to be a subject of intense debate. As an example, plutonium has a half-life of 24,100 years, and a decay of ten half-lives is required before a sample is considered to be safe.^[55][56] The Department of Energy is currently building a vitrification plant on the Hanford Site. Vitrification is a method designed to combine these dangerous wastes with glass to render them stable. Bechtel, the San Francisco based construction and engineering firm, has been hired to construct the vitrification plant, which is currently estimated to cost approximately $12 billion. Construction began in 2001. After some delays, the plant is now scheduled to be operational in 2019, with vitrification completed in 2047. It was originally scheduled to be operational by 2011, with vitrification completed by 2028.^[51][57]

In May 2007, state and federal officials began closed-door negotiations about the possibility of extending legal cleanup deadlines for waste vitrification in exchange for shifting the focus of the cleanup to urgent priorities, such as groundwater remediation. Those talks stalled in October. In early 2008, a $600 million cut to the Hanford cleanup budget was proposed. Washington state officials expressed concern about the budget cuts, as well as missed deadlines and recent safety lapses at the site, and threatened to file a lawsuit alleging that the Department of Energy is in violation of environmental laws.^[51] They appeared to step back from that threat in April after another meeting of federal and state officials resulted in progress toward a tentative agreement.^[58]

A sample of purified plutonium was uncovered inside a safe in a waste trench at the site during excavations from 2004 to 2007, and has been dated to approximately the 1940s, making it the second-oldest sample of purified plutonium known to exist. Analyses published in 2009 concluded that the sample originated at Oak Ridge, and was one of several sent to Hanford for optimisation tests of the T-Plant until Hanford could produce its own plutonium. Documents refer to such a sample, belonging to "Watt's group", which was disposed of in its safe when a radiation leak was suspected.[1][2]

Hanford organizations

The Hanford site operations were initially directed by the U.S. Army Corps of Engineers, followed by the Atomic Energy Commission and then the Energy Research and Development Administration. Hanford operations are currently directed by the U.S. Department of Energy. It has been operated under government contract by a number of private companies over the years - the table which follows summarizes the operating contractors through 2000.^[59]

Other divisions of the site (historical)

• Plutonium Finishing Plant (PFP) - made plutonium metal for use in weapons^[60]
• B Plant, S Plant, T Plant - processing, separation, and extraction of various chemicals and isotopes^[61][62]
• Health Instruments Section - an attempt to keep workers and the environment safe^[62]
• REDOX Plant / C Plant - recovered wasted uranium from WWII processes^[62]
• Experimental Animal Farm and Aquatic Biology Laboratory^[62]
• Technical Center - radiochemistry, physics, metallurgy, biophysics, radioactive sewer, neutralization, metal fab, fuels manufacturing^[62]
• Tank Farms - storage of liquid nuclear waste^[62]
• Metal Recovery Plant / U Plant - recover uranium from tank farms^[62]
• Uranium Trioxide Plant (aka Uranium Oxide Plant aka UO3 Plant) - took output from other plants (i.e. liquid uranyl nitrate hexahydrate from U plant and PUREX plant), made uranium trioxide powder^{[61][62][63][64][65][66][67]}
• Plutonium-Uranium Extraction Plant / PUREX Plant - extracted useful material from spent fuel waste (also see the PUREX article)^[61][62]
• Plutonium Recycle Test Reactor (PRTR) - experimented with alternative fuel mixtures^[60][62]
• Plutonium Fuels Pilot Plant (PFPP) - see PRTR

Historic photos

Cooling water retention basins at the F-Reactor	Underground tank farm with 12 of the site's 177 waste storage tanks	Inside one of the waste storage tanks	Inside the PUREX facility
View of the central plateau from Rattlesnake Mountain	The government town of Richland in the early days of the site	Hanford workers lining up for paychecks	Hanford scientists feeding radioactive food to sheep
Testing a sheep's thyroid for radiation	Cold War-era billboard	"Atomic Frontier Days" parade in Richland	The Fast Flux Test Facility

See also

• Idaho National Laboratory
• Paducah Gaseous Diffusion Plant
• Savannah River Site
• Los Alamos National Laboratory
• Rocky Flats Plant
• Pantex
• Fernald Feed Materials Production Center
• Sandia National Laboratories
• Oak Ridge National Laboratory
• Lists of nuclear disasters and radioactive incidents

References

External links

• Official Hanford website Department of Energy.
• Hanford Challenge Hanford watchdog group, based in Seattle.
• Hanford News Current news from the Tri-City Herald.
• Hanford Site Environmental Report Detailed annual report on radioactive concentrations measured at the Hanford Site.
• Atomic Heritage Foundation Historic Preservation of Manhattan Project Sites at Hanford.
• B Reactor Museum Association A collection of Hanford-related documents from a group fighting to preserve the B-100 Reactor at Hanford.
• Contaminated US site faces 'catastrophic' nuclear leak 2008 New Scientist report.
• Heart of America Northwest Hanford watchdog group, based in Seattle.
• The Alsos Digital Library for Nuclear Issues Annotated bibliography for the Hanford Site.
• A Review of Data Triples Plutonium Waste Figures Matthew L. Wald, The New York Times, 10 July 2010

Manhattan Project Sites Hanford Engineer Works · Oak Ridge National Laboratory · Los Alamos National Laboratory · Berkeley Radiation Laboratory · Chicago Metallurgical Laboratory · Trinity Test Site · Project Alberta · Ames Laboratory · Dayton Project Administrators Vannevar Bush · James Conant · Leslie Groves · Thomas Farrell · Kenneth Nichols · J. Robert Oppenheimer · Franklin D. Roosevelt · Harry S. Truman Scientists Hans Bethe · James Chadwick · Arthur Compton · Enrico Fermi · Richard Feynman · Klaus Fuchs · Ernest Lawrence · William Penney · Emilio G. Segrè · Glenn T. Seaborg · Leó Szilárd · Edward Teller · Stanislaw Ulam · Harold Urey · Leona Woods · Chien-Shiung Wu Related articles Timeline · History of nuclear weapons · Nuclear weapons and the United States · S-1 Uranium Committee · Chicago Pile-1 (Nuclear Energy) · X-10 Graphite Reactor · Y-12 National Security Complex · Operation Alsos · Smyth Report · 509th Operations Group · Fat Man · Little Boy · Enola Gay · Bockscar · The Great Artiste · Atomic bombings of Hiroshima and Nagasaki (debate) See also: All articles in the Manhattan Project category