Pre-discovery use The use of
pitchblende, uranium in its natural
oxide form, dates back to at least the year 79 AD, when it was used in the
Roman Empire to add a yellow color to
ceramic glazes. He named the newly discovered element "Uranit" after the planet
Uranus (named after the primordial
Greek god of the sky), which had been discovered eight years earlier by
William Herschel. He later renamed it "Uranium" to conform to the naming standard. In 1841,
Eugène-Melchior Péligot, Professor of Analytical Chemistry at the
Conservatoire National des Arts et Métiers (Central School of Arts and Manufactures) in
Paris, isolated the first sample of uranium metal by heating
uranium tetrachloride with
potassium. until the
Manhattan Project and the
Cold War placed a large demand on uranium for fission research and weapon development.
Fission research A team led by
Enrico Fermi in 1934 found that bombarding uranium with neutrons produces
beta rays (
electrons or
positrons from the elements produced; see
beta particle). The fission products were at first mistaken for new elements with atomic numbers 93 and 94, which the Dean of the
Sapienza University of Rome,
Orso Mario Corbino, named
ausenium and hesperium, respectively. The experiments leading to the discovery of uranium's ability to fission (break apart) into lighter elements and release
binding energy were conducted by
Otto Hahn and
Fritz Strassmann in Hahn's laboratory in Berlin.
Lise Meitner and her nephew, physicist
Otto Robert Frisch, published the physical explanation in February 1939 and named the process "
nuclear fission". Soon after, Fermi hypothesized that fission of uranium might release enough neutrons to sustain a fission reaction. Confirmation of this hypothesis came in 1939, and later work found that on average about 2.5 neutrons are released by each fission of uranium-235. Fermi urged
Alfred O. C. Nier to separate uranium isotopes for determination of the fissile component, and on 29 February 1940, Nier used an instrument he built at the
University of Minnesota to separate the world's first
uranium-235 sample in the Tate Laboratory. Using
Columbia University's
cyclotron,
John Dunning confirmed the sample to be the isolated fissile material on 1 March. Further work found that the far more common uranium-238 isotope can be
transmuted into plutonium, which, like uranium-235, is also fissile by thermal neutrons. These discoveries led numerous countries to begin working on the development of nuclear weapons and
nuclear power. Despite fission having been discovered in Germany, the
Uranverein ("uranium club") Germany's wartime project to research nuclear power and/or weapons was hampered by limited resources, infighting, the exile or non-involvement of several prominent scientists in the field and several crucial mistakes such as failing to account for impurities in available graphite samples which made it appear less suitable as a
neutron moderator than it is in reality. Germany's attempts to build a
natural uranium /
heavy water reactor had not come close to reaching criticality by the time the Americans reached
Haigerloch, the site of the last German wartime reactor experiment. On 2 December 1942, as part of the
Manhattan Project, another team led by Enrico Fermi was able to initiate the first artificial self-sustained
nuclear chain reaction,
Chicago Pile-1. An initial plan using enriched uranium-235 was abandoned as it was as yet unavailable in sufficient quantities. Working in a lab below the stands of
Stagg Field at the
University of Chicago, the team created the conditions needed for such a reaction by piling together 360 tonnes of
graphite, 53 tonnes of
uranium oxide, and 5.5 tonnes of uranium metal, most of which was supplied by
Westinghouse Lamp Plant in a makeshift production process.
Nuclear weaponry over Hiroshima after the dropping of the uranium-fired '
Little Boy'|alt=White fragmentred mushroom-like smoke cloud evolving from the ground. Two types of atomic bomb were developed by the United States during
World War II: a uranium-based device (codenamed "Little Boy") whose fissile material was highly
enriched uranium, and a plutonium-based device (see
Trinity test and "Fat Man") whose plutonium was derived from uranium-238. Little Boy became the first nuclear weapon used in war when it was detonated over
Hiroshima,
Japan, on 6 August 1945. Exploding with a yield equivalent to 12,500 tonnes of
TNT, the blast and thermal wave of the bomb destroyed nearly 50,000 buildings and killed about 75,000 people (see
Atomic bombings of Hiroshima and Nagasaki). In 1943 the
Manhattan Project contracted two private companies,
Union Carbide and
Chevron, to quietly compile a survey of uranium deposits around the world. As the survey results came in, two geology professors studied the results and suggested general guidelines for new sources, including uranium associated with gold mines in
the Rand area in
South Africa. Initially it was believed that uranium was relatively rare, and that
nuclear proliferation could be avoided by simply buying up all known uranium stocks, but within a decade large deposits of it were discovered in many places around the world.
Reactors (1951)|alt=An industrial room with four large illuminated light bulbs hanging down from a bar. The
X-10 Graphite Reactor at
Oak Ridge National Laboratory (ORNL) in Oak Ridge, Tennessee, formerly known as the Clinton Pile and X-10 Pile, was the world's second artificial nuclear reactor (after Enrico Fermi's Chicago Pile) and was the first reactor designed and built for continuous operation.
Argonne National Laboratory's
Experimental Breeder Reactor I, located at the Atomic Energy Commission's National Reactor Testing Station near
Arco, Idaho, became the first nuclear reactor to create electricity on 20 December 1951. Initially, four 150-watt light bulbs were lit by the reactor, but improvements eventually enabled it to power the whole facility (later, the town of Arco became the first in the world to have all its
electricity come from nuclear power generated by
BORAX-III, another reactor designed and operated by Argonne National Laboratory). The world's first commercial scale nuclear power station,
Obninsk in the
Soviet Union, began generation with its reactor AM-1 on 27 June 1954. Other early nuclear power plants were
Calder Hall in England, which began generation on 17 October 1956, and the
Shippingport Atomic Power Station in
Pennsylvania, which began on 26 May 1958. Nuclear power was used for the first time for propulsion by a
submarine, the
USS Nautilus, in 1954.
Prehistoric naturally occurring fission In 1972, French physicist
Francis Perrin discovered fifteen ancient and no longer active natural nuclear fission reactors in three separate ore deposits at the
Oklo mine in
Gabon, Africa, collectively known as the
Oklo Fossil Reactors. The ore deposit is 1.7 billion years old; then, uranium-235 constituted about 3% of uranium on Earth. This is high enough to permit a sustained chain reaction, if other supporting conditions exist. The capacity of the surrounding sediment to contain the health-threatening
nuclear waste products has been cited by the U.S. federal government as supporting evidence for the feasibility to store spent nuclear fuel at the
Yucca Mountain nuclear waste repository. Additional fallout and pollution occurred from several
nuclear accidents. Uranium miners have a higher incidence of
cancer. An excess risk of lung cancer among
Navajo uranium miners, for example, has been documented and linked to their occupation. The
Radiation Exposure Compensation Act, a 1990 law in the US, required $100,000 in "compassion payments" to uranium miners diagnosed with cancer or other respiratory ailments. During the
Cold War between the Soviet Union and the United States, huge stockpiles of uranium were amassed and tens of thousands of nuclear weapons were created using enriched uranium and plutonium made from uranium. After the
break-up of the Soviet Union in 1991, an estimated 600 short tons (540 metric tons) of highly enriched weapons grade uranium (enough to make 40,000 nuclear warheads) had been stored in often inadequately guarded facilities in the
Russian Federation and several other former Soviet states. saw a strong decline around 2000. In November 2015, the Russian government approved a federal program for nuclear and radiation safety for 2016 to 2030 with a budget of 562 billion rubles (ca. 8 billion
USD). Its key issue is "the deferred liabilities accumulated during the 70 years of the nuclear industry, particularly during the time of the Soviet Union". About 73% of the budget will be spent on decommissioning aged and obsolete nuclear reactors and nuclear facilities, especially those involved in state defense programs; 20% will go in processing and disposal of nuclear fuel and radioactive waste, and 5% into monitoring and ensuring of nuclear and radiation safety. ==Occurrence==