Friday, June 3, 2016

Project Manhattan Hanford Site

When I researched my grand aunt, Henrietta Muir, I purchased her obituary from the archives of the St. Louis Post-Dispatch. The obituary included this tantalizing reference: "During WW II, Ms. Muir was employed at Project Manhattan plant in Hanford, WA." I wanted to know more.

The Manhattan Project was a research and development project that produced the first nuclear weapons during World War II. The project was led by the United States with the support of the United Kingdom and Canada. From 1942 to 1946, the project was under the direction of Major General Leslie Groves of the U.S. Army Cops of Engineers (COE).

In order to produce plutonium, a plant needed to be built. COE worked with DuPont to establish criteria for site selection, which included at least 190 square miles of secure space located at least 20 miles from any sizable town and 10 miles from a major highway. The project needed a water supply of at least 25,000 gallons per minute and an electrical supply of at least 100,000 kilowatts.

In December 1942 the site selection team visited six potential sites. Hanford, Washington, was the last location visited. The Columbia river provided abundant water and the newly completed Grand Coulee Dam could supply the necessary electricity. General Groves endorsed Hanford as the proposed production site in January 1943. Two thousand residents within 580 square miles of the site were given 90 days notice to abandon their homes. Law suites ensued but were settled out of court in favor of time saved.

Construction of the production factory was a formidable challenge and required 50,000 workers. They lived in the Hanford Construction Camp, which included 1,175 buildings. It was the third largest city in Washington State. On Saturday nights, the Patriot Brewery opened for business. It was built specifically to serve the construction workers, who worked in shifts 7 days a week, 24 hours a day. Construction was completed in less than 18 months.

Hanford workers waiting to pick up their paychecks at Western Union; photograph
courtesy of the Hanford Classified Documents Retrial System and Wikipedia

Producing plutonium at Hanford involved three major operations -- fuel fabrication, reactor operations, and chemical separation to extract plutonium. Success was achieved when the first irradiated slugs were discharged from the B Reactor on Christmas Day 1944. By the end of January the highly purified plutonium underwent further concentration in the completed chemical isolation building to remove any remaining impurities. The plant went into full-scale plutonium production on 2 February 1945 when it received its first shipment of plutonium.


  1. It is amazing to see how much work came as a result of the war and women's part in helping in that effort. This certainly adds an interesting detail to your ancestor's life.

  2. Amazing stuff you blog. My 2nd cousin once removed Truly Hardy worked on the Manhattan Project as well.

    1. Thank you, Mark. The Manhattan Project is amazing history.