Electricity was generated for the first time by a nuclear reactor on December 20, 1951, at the EBR-I experimental station near Arco, Idaho, which initially produced about 100 kW (the Arco Reactor was also the first to experience partial meltdown, in 1955). In 1952, a report by the Paley Commission for President Harry Truman made a "relatively pessimistic" assessment of nuclear power, and called for "aggressive research in the whole field of solar energy.” A December 1953 speech by President Dwight Eisenhower, "Atoms for Peace," emphasized the useful harnessing of the atom and set the U.S. on a course of strong government support for international use of nuclear power.

The idea behind the breeder is to maximize the useful energy that can be extracted from natural uranium.

Inside a nuclear reactor, uranium-238 — the common form of the metal which cannot be used for fuel — can capture neutrons released during fission and transform into plutonium-239. This man-made element can fuel reactors, so breeding makes it possible to use virtually 100 percent of the energy in natural uranium.

EBR-I provided the first proof that breeding is possible: On June 4, 1953, the U.S. Atomic Energy Commission announced that EBR-I had become the world's first reactor to demonstrate the breeding of plutonium from uranium.

http://en.wikipedia.org/wiki/Nuclear_power#History