The Hanford Site occupies approximately 1,450 square kilometers (560 square miles) of shrub-steppe ecosystem in the southeastern part of the state of Washington. The sparsely populated site is the location of archeological sites dating back more than 18,000 years. The Columbia River, which forms the Hanford Site’s eastern boundary, sustains numerous fish and wildlife species, and is the source of irrigation and drinking water to Pacific Northwest communities. The river is also significant in the culture of the Tribal people. The city of Richland is located at the southeast border of the site and the cities of Kennewick and Pasco are located within 24 kilometers (15 miles) southeast of the site. Approximately 100,000 people occupy these three cities.

The Manhattan Project began in late 1942. Collectively, the workers in many States on the Manhattan Project took on a nearly impossible challenge to address a grave threat to the national security by Hitler’s Germany and Japan. The initial phase of its development, beginning during World War II and conducted by the U.S. Army Corps of Engineers Manhattan Engineer District (MED), involved the rapid construction of three sites: one for uranium enrichment (Oak Ridge, Tennessee); one for plutonium production (Hanford, Washington); and one for the research, design, and production of the first wartime atomic weapons (Los Alamos, New Mexico). A large number of private contractors supported these three sites by processing uranium ore into reactor fuel and enrichment feed stock. The successful production of atomic bombs brought the end of World War II. After the war, authority over the nuclear weapons complex transferred to the recently-formed Atomic Energy Commission (AEC). Over the next decade, a major expansion coincided with a shift toward government-owned production facilities. Redundant facilities ensured that nuclear weapons production would not be interrupted by a problem at any single site. By the mid-1950s, all of the major weapons complex facilities had been established. The U.S. Government established the Hanford Engineering Works in 1943 to support the nation’s war-time effort to produce plutonium for the world’s first nuclear weapons. In 30 months, the Manhattan Project built three reactors, three chemical processing plants to recover plutonium from irradiated fuel, and 64 underground storage tanks. It also built a production reactor fuel fabrication facility and other support facilities.

In January 1943, the U.S. Army Corps of Engineers selected the Columbia Basin as the location for the nation’s first full-sized plutonium production operation. Selection criteria developed in 1942 called for a large, remote tract of land with room for a manufacturing area at least 19 by 26 kilometers (12 by 16 miles), space for laboratory facilities at least 13 kilometers (8 miles) from the nearest reactor or processing plant, and abundant water and electricity. The Hanford Site met these criteria.

The Manhattan Project developed plans to build production reactors along the Columbia River (100 Area); processing plants and associated facilities on a plateau near the center of the site (200 Area); and the fuel fabrication buildings, laboratories, and other support facilities near the site’s southern boundary (300 Area). In 1967, the Atomic Energy Commission designated part of the Hanford Site and arid lands ecology reserve. During the production of plutonium, Hanford Site involved three steps: 1) fuel fabrication, in which uranium was fabricated into fuel elements in the 300 Area of the site; 2) fuel irradiation, in which fuel elements were irradiated in nuclear reactors in the 100 Area, converting small amounts of the uranium fuel to plutonium; and 3) chemical processing, in which the irradiated fuel elements or “slugs” were chemically processed to extract the plutonium in the 200 Area facilities. The uranium fuel fabrication processes took place in the 313 Metal Fabrication Building and the 314 Press Building. The 313 Building was used to machine uranium rods to desired dimensions for use in Hanford’s reactors, jacket (“can”) the sized fuel elements, and test the jackets for proper bonding and sealing. The 314 Building contained equipment to extrude raw uranium billets into rods and perform final tests on the jacketed elements. During the 1940s and 1950s, eight reactors were built in the 100 Area. The fuel for these rectos was fabricated in the 300 Area. The spent fuel discharged from the reactors was chemically processed to recover uranium and plutonium. N Reactor, which became operational in 1963, was used for both plutonium production and steam generation. In addition to the production reactors, there were two test reactors. The Plutonium Research Test Reactor is located in the 300 Area, and the much larger Fast Flux Test Facility reactor is in the 400 Area. These test reactors were used in fuel materials, isotope production, and power research.

After the fabricated fuel had been irradiated in the production reactors, the fuel slugs were chemically separated in the 200 Area where the plutonium was extracted. The processing buildings included the Plutonium-Uranium Extraction Plant, where spent fuel was processed to extract plutonium and unused uranium; the Uranium Oxide Plant, where uranium nitrate was converted to uranium oxide powder for recycling; and the Plutonium Finishing Plant, where plutonium metal was fashioned. In addition, Hanford used the B Plant for bismuth phosphate processing and separation and purification of cesium and strontium for encapsulation; C Plant (Hot or Strontium Semiworks) for separation and process development; S Plant (Reduction-Oxidation Plant), for separation through solvent extraction; T Plant for bismuth phosphate process separation and subsequent use as a decontamination and repair facility; and U Plant for chemical separation and processing.

Shortly after World War II, relationship between the United States and the former Soviet Union began to sour, and the Cold War ensued. The nuclear arms race between U.S. and Soviet Union resulted in the development of a vast research, production, and testing network that came to be known as the “nuclear weapon complex.” Beginning in 1964, the Department sharply curtailed plutonium production in response to the nation’s changing defense needs. By 1971, eight of the nine production reactors had bee shut down and by 1972, all related fuel separation facilities, including the Plutonium-Uranium Extraction Plant, had ceased operations. In the early 1980s, the department briefly restarted the Plutonium-Uranium Extraction Plant and the Uranium Oxide Plant; however these plants are now permanently shut down.

As a result of the reduction of plutonium production activities, the resources and capabilities of the Hanford Site were refocused toward developing nonmilitary applications and peaceful uses of radiation and nuclear energy. In the 1970s, the Energy Research and Development Administration, a predecessor to the Department of Energy, emphasized energy research programs, including solar, geothermal, and advanced systems; fossil energy; national security; conservation; energy policy analysis; and resources assessment. During this period, the full-size advanced test reactor, and the Fast Flux Test Facility were used for large-scale nuclear fuels testing in support of nuclear energy research. Several years after, a national laboratory, Pacific Northwest National Laboratory, began in 1965.