Hanford Engineer Works

The Hanford Engineer Works (HEW) was a nuclear production complex in Benton County, Washington, established by the United States federal government in 1943 as part of the Manhattan Project during World War II. It built and operated the B Reactor, the first full-scale plutonium production reactor. Plutonium manufactured at the HEW was used in the atomic bomb detonated in the Trinity test in July 1945, and in the Fat Man bomb used in the atomic bombing of Nagasaki in August 1945. The HEW was commanded by Colonel Franklin T. Matthias until January 1946, and then by Colonel Frederick J. Clarke.

The director of the Manhattan Project, Brigadier General Leslie R. Groves Jr., engaged DuPont as the prime contractor for the design, construction and operation of the HEW. DuPont recommended that it be located far from densely populated areas, and a site on the Columbia River, codenamed Site W, was chosen. The federal government acquired the land under its war powers authority and relocated some 1,500 nearby residents. The acquisition was one of the largest in US history. Disputes arose with farmers over the value of the land and compensation for crops that had already been planted. The acquisition was not completed before the Manhattan Project ended in December 1946.

Construction commenced in March 1943 on a massive and technically challenging project. Most of the construction workforce, which reached a peak of nearly 45,000 in June 1944, lived in a temporary construction camp near the old Hanford townsite. Administrators, engineers and operating personnel lived in the government town established at Richland, which had a wartime peak population of 17,000. The HEW erected 554 buildings, including three graphite-moderated and water-cooled reactors (B, D and F) that operated at 250 megawatts. Natural uranium sealed in aluminum cans (known as "slugs") was fed into them.

B Reactor went critical in September 1944 and, after overcoming neutron poisoning, produced its first plutonium in November. Irradiated slugs were processed in two huge, remotely operated chemical separation plants (T and B) where the plutonium was extracted using the bismuth-phosphate process. Radioactive wastes were stored in underground tanks. The first batch of plutonium was processed in the T plant between December 1944 and February 1945 and delivered to the Manhattan Project's Los Alamos Laboratory. The identical D and F reactors came online in December 1944 and February 1945, respectively. The HEW suffered an outage on 10 March 1945 when a Japanese balloon bomb struck a high-tension power line. The total cost of the HEW up to December 1946 was over $348 million (equivalent to $4.1 billion in 2023). The Manhattan Project ended on 31 December 1946 and control of the HEW passed from the Manhattan District to the Atomic Energy Commission.