World’s First Breeder Reactor Produces Electricity

Engineers and physicists at the Idaho National Engineering Laboratory successfully produced electricity from nuclear fission and in the process generated new fuel, demonstrating the viability of breeder reactors.

Summary of Event

The discovery of nuclear fission Nuclear fission involved not only the discovery that a nucleus would split into two lighter elements but also the observation that significant amounts of energy were released at the same time. Besides the possibility that an explosive weapon could be constructed, early speculation about nuclear fission included its use in the generation of electricity. The occurrence of World War II meant that the explosive weapon was developed first. This was the first of several key decisions in the progress of nuclear science and its applications. Fear of what the enemy might be doing spurred the weapon program. Both the weapon technology and the basic physics for the electrical reactor had their beginnings in Chicago with the first nuclear chain reaction. Nuclear energy;reactors
Breeder reactors
Experimental Breeder Reactor 1
[kw]World’s First Breeder Reactor Produces Electricity (Dec. 20, 1951)[Worlds First Breeder Reactor Produces Electricity]
[kw]Breeder Reactor Produces Electricity, World’s First (Dec. 20, 1951)
[kw]Reactor Produces Electricity, World’s First Breeder (Dec. 20, 1951)
[kw]Electricity, World’s First Breeder Reactor Produces (Dec. 20, 1951)[Electricity, Worlds First Breeder Reactor Produces]
Nuclear energy;reactors
Breeder reactors
Experimental Breeder Reactor 1
[g]North America;Dec. 20, 1951: World’s First Breeder Reactor Produces Electricity[03660]
[g]United States;Dec. 20, 1951: World’s First Breeder Reactor Produces Electricity[03660]
[c]Energy;Dec. 20, 1951: World’s First Breeder Reactor Produces Electricity[03660]
[c]Engineering;Dec. 20, 1951: World’s First Breeder Reactor Produces Electricity[03660]
[c]Science and technology;Dec. 20, 1951: World’s First Breeder Reactor Produces Electricity[03660]
Zinn, Walter Henry

The first self-sustaining nuclear chain reaction occurred in a laboratory at the University of Chicago on December 2, 1942. It also became apparent at that time that there was more than one way to build a bomb. At this point, two paths were taken: One was to build an atomic bomb with enough fissionable uranium in it to explode when detonated, and another path was to generate fissionable plutonium and build a bomb. In either process, energy was released, but the second method also produced another fissionable substance.

The observation that plutonium Plutonium and energy could be produced together meant that it would be possible to design electric-power systems that would simultaneously produce fissionable plutonium in quantities as large as, or larger than, the amount of fissionable material consumed. This was the breeder concept, the idea that while using up fissionable uranium 235 (U-235), another fissionable element could be made. Putting this concept into practice was delayed until the end of World War II, when the Fast Breeder Reactor (FBR) program Fast Breeder Reactor program began.

On August 1, 1946, the Atomic Energy Commission Atomic Energy Commission, U.S.;experimental reactors (AEC) was established to control the development of nuclear energy and explore the peaceful uses of nuclear energy. The Argonne National Laboratory Argonne National Laboratory was assigned the major responsibilities for pioneering breeder reactor technologies; Walter Henry Zinn was its first director. He led the team to plan a modest facility (Experimental Breeder Reactor 1, or EBR-1) for testing the validity of the breeding principle. Planning for this facility had begun in late 1944 and grew as a natural extension of the physics that developed the plutonium atomic bomb.

The conceptual design details for a breeder-electric reactor were reasonably complete by late 1945. On March 1, 1949, the AEC announced the selection of a site in Idaho for the National Reactor Station (later to be named the Idaho National Engineering Laboratory Idaho National Engineering Laboratory , INEL). Construction at the INEL site in Arco, Idaho, began in October, 1949. In August, 1951, the reactor achieved criticality, meaning that the nuclear fission reaction at its core became self-sustaining, as natural fission induced more fission in the nuclei of atoms neighboring that core.

The system was brought to full operating power, 1.1 megawatt of thermal power, on December 19, 1951. The next day, December 20, at 11:00 a.m., steam was led to a turbine-generator. At 1:23 p.m., the generator was connected to the electrical grid at the site, and “electricity flowed from atomic energy,” in the words of Zinn’s console log of that day. Approximately two hundred kilowatts of electric power were generated most of the time that the reactor was run. This was enough to satisfy the needs of the EBR-1 facilities. The reactor was shut down in 1964, after five years of use primarily as a test facility, studying various fuel assemblies and cladding material for fuels. It also produced the first pure plutonium.

The reactor had several unique features, because it was a first. It was also very different from the common light-water nuclear reactors now used commercially throughout the United States to produce electricity. Among its key features, liquid metal, a sodium-potassium alloy that is a liquid at room temperatures, was used as a coolant through the reactor instead of water. The first several fuel loadings used highly enriched uranium (93 percent) metallic fuel, not the 3 percent fuel that is common in ordinary light-water reactors and not the oxide or ceramic form of the fuel. The neutrons that result from the fission and that perpetuate the chain reaction were not slowed down, or moderated, to thermal speeds—hence, the name Fast Breeder Reactor, as distinguished from the more common thermal-neutron reactors. It is fast neutrons that allow the transmutations that produce the plutonium used as the new fuel.

With the first fuel loading, a conversion ratio of 1.01 to 1 was achieved, meaning that about 1 percent more new fuel was generated than was consumed. When later fuel loadings were made with plutonium, the conversion ratios were more favorable, reaching as high as 1.27 to 1. EBR-1 was the first reactor to generate its own fuel and the first power reactor to use plutonium as a fuel.

The use of EBR-1 also meant pioneering work on fuel recovery and reprocessing. During its five-year lifetime, EBR-1 operated with four different fuel loadings, each designed to establish specific benchmarks of FBR technology. This reactor was seen as a first in a series of increasingly larger reactors in a program to develop the breeder technology fully. The reactor was replaced by EBR-2, Experimental Breeder Reactor 2 which had been proposed in 1953 and was constructed from 1955 to 1964. EBR-2 was capable of 62.5 megawatts of thermal power (20 megawatts electrical), making it approximately fifty times more powerful than EBR-1 but still small compared to light-water commercial reactors of 600 to 1,100 megawatts (electrical) in use in the early twenty-first century.

The production of electricity and the lighting of a string of light bulbs was the event that made newspaper headlines on December 20, 1951. There were other, less photogenic breakthroughs; among the significant engineering achievements was the use of a liquid-metal coolant. The sodium-potassium alloy used in EBR-1 reacted explosively with water, yet was used to turn water into steam. This system called for several engineering feats. Liquid metal was chosen for this particular reactor in Idaho because of its tremendous thermal conductivity. Liquid sodium is many times more efficient at transferring heat than is water.

The high efficiency of liquid metal coolant meant that the system could tolerate an intermediate loop, or secondary loop, of coolant between the reactor and the steam generators. The existence of the secondary loop served as a safety feature in the event that some of the coolant should inadvertently react with some of the water being turned into steam. Liquid metal coolants are used in the major breeder reactors in operation around the world. Their high heat-transfer abilities offer other safety features, making them highly desirable and worthy of this developmental effort.

Following the completion of tests with the plutonium loading in 1964, EBR-1 was shut down and placed in standby status. In 1966, it was declared a national historical landmark under the stewardship of the U.S. Department of the Interior. The facility was opened to the public in June, 1975.


Some historians describe the World War II race for an atomic bomb as one that pitted the scientists of Germany against those of the United States, England, and Canada. Some of those historians relate that the initial German interest in nuclear fission saw its potential for the production of electricity as more interesting than its potential as a weapon or a super bomb. The potential for peaceful uses of nuclear fission were dramatized with the activation of EBR-1 in 1951. It was the first in the world to produce electricity, although it was also the pioneer in a breeder reactor program. The breeder program was not the only reactor program being developed and eventually lost out to the light-water reactor design for use in the United States. This was another of the major decision points in nuclear power development.

The full impact of the choice between breeder reactors and light-water reactors can be appreciated with a look at uranium. Nuclear fission supplies many times more energy than does the combustion of fossil fuels. In doing so, fission makes use of the rare isotope of uranium capable of undergoing fission, U-235. This isotope accounts for less than 1 percent of naturally occurring uranium, and uranium is not considered to be an abundant element. Thus, while powerful, U-235 is rare. By developing a breeder reactor with fast neutrons, otherwise unfissionable uranium can be transmuted into a fissionable form of plutonium, thus generating new fuel as well as power.

EBR-1, EBR-2, and the intended Clinch River Breeder Reactor Clinch River Breeder Reactor were part of the U.S. plan to develop breeder-reactor technology. It was argued that this technology would make the best use of limited uranium reserves. The Clinch River Breeder Reactor became a 1980 goal of President Richard M. Nixon in 1971; however, in 1977, President Jimmy Carter announced his plans to defer the FBR program. President Carter wanted to minimize the proliferation of fissionable material—material that could possibly make its way into a nuclear weapon. In 1983, the United States Congress terminated funding for the Clinch River Breeder Reactor. At that time, EBR-2 had run continuously for nineteen years.

In the United States, various versions of the light-water reactor became the technology for general electrical production. The first commercial reactor, the Shippingport Atomic Power Station, near Pittsburgh, Pennsylvania, was a scaled-up version of the reactor used in the submarine USS Nautilus. These light-water reactors burn fissionable U-235. They do not use the reactive liquid metal coolant, and because they incorporate thermal neutrons, they do not generate new fissionable material. They do not require fuel reprocessing. Nuclear energy;reactors
Breeder reactors
Experimental Breeder Reactor 1

Further Reading

  • Allardice, Corbin, and Edward R. Trapnell. The Atomic Energy Commission. New York: Praeger, 1974. A brief history of the AEC written from firsthand observations of early Atomic Energy Commission employees.
  • Compton, Arthur Holly. Atomic Quest. New York: Oxford University Press, 1956. A personal account of the research that led to the release of atomic energy by one who was an active participant in the atomic bomb work and the reactor development programs.
  • Dean, Gordon E. Report on the Atom. 2d ed. New York: Alfred A. Knopf, 1957. A description by a former commission chairman of the major parts of the United States’ atomic energy program in the 1950’s.
  • Holl, Jack M., Roger M. Anders, and Alice L. Buck. United States Civilian Nuclear Power Policy, 1954-1984: A Summary History. Springfield, Va.: National Technical Information Sources, 1986. Factual and without interpretation. For the technical reader.
  • Little (Arthur D.) Inc. Atoms for Peace: U.S.A. 1958. Edited by John F. Hogerton. Cambridge, Mass.: United States Atomic Energy Commission, 1958. A pictorial representation of the early atomic installations in the United States.
  • Mazuzan, George T., and J. Samuel Walker. Controlling the Atom: The Beginnings of Nuclear Regulation, 1946-1962. Berkeley: University of California Press, 1985. A comprehensive study.
  • Murray, Raymond L. Understanding Radioactive Waste. 5th ed. Columbus, Ohio: Battelle Press, 2003. Easy-to-understand explanation of fuel reprocessing and waste handling.
  • Rhodes, Richard. The Making of the Atomic Bomb. New York: Simon & Schuster, 1986. A charming and very readable account of the people, the politics, and the times up to the breeder reactor technology.
  • Zebroski, E. L., et al., eds. Advanced Nuclear Reactors: Current Developments and Future Prospects. New York: Elsevier, 1998. Originally published as a special issue of Energy, this compilation discusses breeder reactors and fusion reactors and the technologies involved in each.

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