By 1941 Glenn T. Seaborg, Edwin M. McMillan, Philip H. Abelson, and others at the Radiation Laboratory, Berkeley, California, had identified isotopes of two new transuranic elements developed when they bombarded ²³⁸U nuclei with neutrons. The new elements were named neptunium and plutonium after the planets Neptune and Pluto, which lie beyond Uranus in the solar system.[4] One isotope of plutonium, plutonium-239, which resulted from the absorption of a neutron by a ²³⁸U nucleus and the emission of two beta particles, was discovered to be as fissionable as ²³⁵U and hence theoretically just as feasible for a bomb. Since plutonium is chemically different from uranium, it offered the tremendous advantage that it could readily be concentrated by conventional chemical techniques.
The way to manufacture usable amounts of plutonium, an element that had never before been detected on earth, is to expose uranium to a very intense neutron bombardment. The best-known place to find a rich supply of neutrons was the heart of a self-sustaining chain-reacting pile of uranium. Accordingly, very large piles, or reactors, were rushed to completion near the Columbia River at Hanford, Washington, to make plutonium.
First atomic bomb explosion at Alamagordo, New Mexico, at 5:30 a.m. on July 16, 1945.
Courtesy U. S. Army
On July 16, 1945, a plutonium bomb, carefully assembled by another group of scientists at “Project Y,” Los Alamos, New Mexico, was successfully tested in the New Mexico desert. The heat from that first man-made nuclear explosion completely vaporized a tall steel tower and melted several acres of surrounding surface sand. The flash of light was the brightest the earth had ever witnessed.
A ²³⁵U bomb was dropped on Hiroshima, Japan, on August 6, 1945. Three days later a plutonium bomb was dropped on Nagasaki, Japan. Hostilities ended on August 14, 1945.
Nuclear Energy Is Needed for the Future
The chief source of the enormous quantities of energy used daily by modern civilization is fossil fuels in the form of coal, petroleum, and natural gas. Concentrated sources of these fuels, though large, are far from inexhaustible, and it has been said that future historians may refer to the brief time when they were used as “the fossil-fuel incident.”
These lights of downtown Pittsburgh are symbolic of the generation of electricity by atomic power from Shippingport, Pennsylvania, the site of the world’s first full-scale atomic-electric generation station exclusively for civilian needs. Homes and factories of the greater Pittsburgh area are receiving the electricity produced at the plant and transmitted through the Duquesne Light Company system. The Shippingport plant is a joint project of Westinghouse Electric Corporation, U. S. Atomic Energy Commission, and the Duquesne Light Company.
Courtesy Westinghouse Electric Corporation