Tag Archives: Manhattan Project

Leslie Richard Groves

General Groves oversaw the construction of the Pentagon, but more notably, directed the Manhattan Project that developed the atomic bomb during World War II.

Groves died on July 13, 1970, at 73 years of age. He is interred in Arlington National Cemetery, next to his brother, Allen, who died of pneumonia in 1916. Grace, his wife, was interred next to Groves in 1986.

The tombstone marks his participation in the Manhattan Project along with the insignia. The grave faces the Pentagon, which can be seen in the distance.

Plutonium Scale

Seederer-Kohlbush scale @ Hanford B Reactor

This Seederer-Kohlbusch scale, circa 1944, is found in a side room of the B Reactor at Hanford along with displays of other artifacts and mementos of the Manhattan Project. This is the original scale used to weigh the first milligrams of plutonium (Pu) produced at the facility.

Hanford B Reactor

In October 1943, construction began on the B Reactor at the Hanford Site in Washington, with the purpose of producing plutonium. Fuel slugs — uranium billets extruded into slugs and sealed in aluminum jackets — were then placed in the reactor for several weeks to a year. The reactor went critical on September 26, 1944. The first irradiated slugs were discharged from the reactor on December 25, 1944.

T Plant located in 200 West Area of Hanford. (T Plant @ Hanford.gov)

Fuel slugs were then removed from the reactor and placed in a 90-day underwater cooling off period before being transported by train to the Hanford T Plant, which began operations on December 26, 1944. Next, the bismuth phosphate process was used on the fuel slugs to separate the plutonium from uranium and other fission products. The final processed product was plutonium nitrate, which made for safer shipping to Los Alamos.

In late January, 1945, the first milligrams of plutonium produced at Hanford were weighed on this scale then sent by courier to Los Alamos for testing. Los Alamos received its first plutonium from Hanford on February 2, 1945.

Building D, Tech Area, Los Alamos (Tech Area Gallery @ OSTI.gov)

Subsequently, Building D in the Tech Area at Los Alamos would purify and fabricate the plutonium nitrate received from Hanford into the highly purified metallic hemispheres used in the Trinity and Nagasaki devices.

For further reading:

Chicago Pile-1

December 2, 1942

Henry Moore’s sculpture, Nuclear Energy, at the site of the first controlled nuclear fission reaction on the University of Chicago campus.

On this day on December 2, 1942, Enrico Fermi and colleagues conducted the first controlled nuclear fission reaction at the University of Chicago (Chicago Pile-1). The site was designated a National Historic Landmark in 1965. This Henry Moore sculpture, Nuclear Energy, was placed at the site on the 25th anniversary in 1967.