nuclear energy

1. The energy released by a nuclear reaction, especially by fission or fusion.
2. Nuclear energy regarded as a source of power. Also called atomic energy.

Energy that can be liberated by changes in the nucleus of an atom.

All forms of energy released in the course of nuclear fission or nuclear transformation.

See the Introduction, Abbreviations and Pronunciation for further details.

For more information on nuclear energy, visit Britannica.com.

The Soviet Union had an extensive atomic energy program. The program included the use of isotopes as tracers for agricultural research and as ionizing sources for food irradiation, extensive applications in medicine, so-called peaceful nuclear explosions, and an ambitious effort to build scores of reactors to produce electrical energy. Under the regime of Josef Stalin, the military side of atomic energy was significantly more developed than its civilian application. Scientists and workers were gathered into closed cities to build the first Soviet atomic bomb, detonated in 1949, and to design and assemble tens of thousands of nuclear warheads. It is not certain what percentage of the nuclear program was civilian and what percentage was military, but it is clear that the military needs predominated during the Cold War. It is also difficult to draw a line between military and civilian programs. Nikita Khrushchev and Leonid Brezhnev made the peaceful atom a centerpiece of their economic development programs. The peaceful atom found expression in art and music, on stamps and lapel pins, and even in literary works. For instance, the Exhibition of the Achievements of the Socialist Economy (VDNKh) had a large hall devoted to atomic energy. However, even when the technology was ostensibly dedicated to peaceful goals, there were often military interests at stake as well. For example, Soviet scientists conducted 120 peaceful nuclear explosions (PNEs) for excavation, dam construction, and other purposes that were connected with the 1963 ban against atmospheric testing of nuclear devices.

Cold War Developments

Atomic energy was a prominent fixture of the Cold War, as part of competition with the United States for military superiority and for economic and ideological influence. In a propaganda coup in 1954, Soviet officials announced the opening of the Obninsk five-thousand kilowatt reactor, the first station to provide electrical energy for peaceful purposes (it remained open and operational until 2002). Over the next three decades, each subsequent Soviet achievement received extensive media coverage. Soviet scientists actively participated in the Geneva Conferences on the Peaceful Uses of Atomic Energy. The first, in 1956, enabled Soviet physicists to appear as equals of their American and European counterparts.

The conferences were crucial in allowing Soviet physicists to participate in the broader scientific community, an opportunity that had been denied them during the Stalin era because of its extreme commitment to secrecy. At conferences, scientists from the USSR could enter into serious discussions with their international colleagues, and these interactions often eased Cold War tensions. For instance, Igor Kurchatov, the head of the atomic bomb project, spent the last years of his life promoting peaceful nuclear programs and sought a test ban treaty of some sort.

Development of Nuclear Reactors

Soviet engineers developed five major kinds of nuclear reactors. One design focused on compactness, and was intended to be used for propulsion, especially for submarines. The USSR also employed compact reactors on aircraft carriers, container ships, freighters, and icebreakers, such as the icebreaker Lenin, which was launched in 1959. Scientists also worked on reactor propulsion for rockets and jets, and nuclear power packs for satellites. There were several prototype land-based models, including the TES-3, built in Obninsk, that could be moved on railroad flatbed cars or on tank treads. In the 1990s, Russian nuclear engineers designed a barge-based, floating nuclear unit for use in the Far North and Far East.

There was also an extensive breeder reactor program. The most common type was the liquid metal fast breeder reactor (LMFBR). Breeder reactors are so called because they use "fast" neutrons from fissile uranium (U235) to transmute non-fissile U238 into plutonium (Pu239). The plutonium can then be used to power other breeder reactors, or as fuel for nuclear weapons. Breeder reactors are highly complex. They have a liquid metal, usually sodium, coolant, which must be kept separate from the water used for power generation, because the sodium will burst into flame when mixed with water.

The physicists A. I. Leipunsky and O. D. Kazachkovsky established the LMFBR program in 1949, over the years building a series of increasingly powerful experimental reactors. In the late 1960s, they built the BOR-60 with the hope that it would double (or breed) plutonium every eight years. Like its predecessors and subsequent models, the BR-60 had an extended operational lifespan, but also required long periods of repair time because of pump breakdowns, ruptured fuel assemblies, sodium leaks, and fires.

Leipunsky and Kazachko were determined to build industrial prototype reactors as well. In 1979 they built the BN-350 on the Mangyshlak Peninsula on the shore of the Caspian Sea. The reactor provided both electrical energy and desalinated 120,000 cubic meters of water daily for the burgeoning petrochemical industry. At Beloiarsk they built a 600 megawatt model (the BN-600), followed by an 800 megawatt model (the BN-800), and aimed to create a network of 1,600 megawatt LMFBRs that would be capable of producing plutonium sufficient for all military and civilian ends. Cost overruns and accidents left the program weakened, however.

Other Achievements and Problems

The mainstay of the Soviet (and Russian) atomic energy effort has been the development of 440 and 1,000 megawatt pressurized water reactors, known by the Russian designation as VVER reactors. Also important were the channel-graphite reactors (RMBK in Russian), such as the one built at Chernobyl. The USSR supported the diffusion of VVERs beyond its borders, especially into Eastern Europe (Hungary, Czechoslovakia, and Bulgaria), and two 1,500 MW RMBKs in Lithuania. The VVERs have been largely reliable by Soviet standards, although the first generation facilities lack any containment buildings or other safety equipment that has become standard in the West.

Reactors had to include more expensive containment design features if they were to be competitive in Western markets, as when the USSR sold its VVER-440s to Finland. In an effort to reduce costs, speed construction, and limit chances for worker error in the field, the nuclear industry built the Atommash Factory in Volgodonsk on the lower Volga River. Atommash was intended to construct eight reactor pressure vessels and associated equipment annually by 1983. The massive factory required the investment of millions of rubles and employed tens of thousands of workers. Yet it never operated as intended, producing only three vessels in all before one wall of the main foundry collapsed.

RMBKs have been even more problematic. Anatoly Alexandrov, later the president of the Academy of Sciences and Kurchatov's successor, pushed the RMBK reactor. Their advantages are that they continue to operate during constant refueling, theoretically could be built in sizes up to 2,400 megawatts (forecast, not built), and produce plutonium, which is coveted by military planners. Yet they use ordinary factory structures and have no containment whatsoever. On the other hand, they have suffered from premature aging. Worse still, the RBMK is highly unstable at low power, an inherent fault that contributed to the Chernobyl disaster. The flagship of the RBMK is the Leningrad station, with four units built between 1973 and 1984. In 2002 the Ministry of Atomic Energy (MinAtom) announced plans to attempt to prolong the operational lives of these four reactors and to build another two units on the site. This continues the Soviet practice of building reactors in close proximity to populated areas and industrial centers in so-called parks that have been designed to share equipment and thus to keep costs down.

Initially, the public enthusiastically embraced atomic energy as a symbol of Soviet scientific prowess and cultural achievement. However, the inherent weaknesses of the RBMK and the dangers of the mindset of Soviet engineers who believed in the perfectibility of their technology and the desirability of unlimited reactor construction became painfully clear at Chernobyl in April 1986. As a result of an experiment that was poorly designed and even more poorly carried out, the Chernobyl facility's unit four (of four operating, with six others planned) exploded, spewing roughly 120 million curies of radioactivity into the atmosphere. This led to a fire that killed thirty-one firefighters outright, and required the evacuation of all people within a thirty-kilometer radius of the station. Soviet officials hesitated to announce the extent of the crisis at Chernobyl for several days after the event. This hesitation revealed that Mikhail Gorbachev himself was unsure how far to pursue his policy of glasnost ("openness") and seriously damaged the public image of the atomic energy program.

A major research program centered on controlled thermonuclear synthesis, or fusion. Andrei Sakharov and Igor Tamm developed the idea for the electromagnetic containment of a plasma in a toroid-shaped reactor at millions of degrees temperature. The plasma would fuse two lighter elements into a heavier one, releasing tremendous amounts of energy that could then be used to generate electricity. This model has come to be known throughout the world by its Russian name, tokamak, and has been the most successful fusion device developed by the end of the twentieth century. Soviet scientists remained world leaders in this field, with programs at institutes in Leningrad, Kharkiv, Akademgorodok, Moscow, and elsewhere. Cost efficiency has been a problem however. Since the program commenced in the early 1950s, it has yet to achieve the break-even point where the cost tooperate fusion devices has been offset by the returns gained through energy production. In 1985, Mikhail Gorbachev suggested a Soviet-American alliance in fusion research to President Ronald Reagan at their Geneva summit.

Program Legacies

One of the legacies of atomic energy in the USSR has been the production of thousands of tons and millions of gallons of high- and low-level radioactive waste. The waste has been stored haphazardly, often in open areas, and for a number of years the Soviets dumped waste, including spent reactor vessels, into the world's oceans. The waste has been spreading throughout the world's ecosystems for decades. There have been a series of disasters connected with waste disposal, including the explosion of a waste dump at Kyshtym in 1957, a disaster at Lake Karachai in 1953, and several others. As of 2002, Russia faced financial and technical difficulties in complying with international agreements regarding the disposal of radioactive waste and in destroying obsolete military equipment such as decommissioned nuclear submarines. The human and environmental costs of the Soviet atomic energy program thus remain extremely high. In spite of this, the Russian Ministry of Atomic Energy has established plans to expand the nuclear enterprise significantly by the year 2020, with the construction of up to forty additional reactors and the diffusion of floating nuclear power stations.

Bibliography

Holloway, David. (1994) Stalin and the Bomb. New Haven, CT: Yale University Press.

Josephson, Paul. (1999). Red Atom. New York: Freeman.

Medvedev, Zhores. The Legacy of Chernobyl. New York: Norton.

—PAUL R. JOSEPHSON

Energy obtained from nuclear reactions.

(DOD) All forms of energy released in the course of a nuclear fission or nuclear transformation.

It has been suggested that this article or section be merged with Binding energy. (Discuss)

This article is about nuclear energy in physics. For the use of nuclear fission as a power source, see Nuclear power. For the sculpture, see Nuclear Energy (sculpture).

Nuclear energy is released by the splitting (fission) or merging together (fusion) of the nuclei of atom(s). The conversion of nuclear mass to energy is consistent with the mass-energy equivalence formula ΔE = Δm.c², in which ΔE = energy release, Δm = mass defect, and c = the speed of light in a vacuum (a physical constant). Nuclear energy was first discovered by French physicist Henri Becquerel in 1896, when he found that photographic plates stored in the dark near uranium were blackened like X-ray plates, which had been just recently discovered at the time 1895.^[1]

Nuclear chemistry can be used as a form of alchemy to turn lead into gold or change any atom to any other atom (albeit through many steps).^[2] Radionuclide (radioisotope) production often involves irradiation of another isotope (or more precisely a nuclide), with alpha particles, beta particles, or gamma rays. Iron has the highest binding energy per nucleon of any atom. If an atom of lower average binding energy is changed into an atom of higher average binding energy, energy is given off. The chart shows that fusion of hydrogen, the combination to form heavier atoms, releases energy, as does fission of uranium, the breaking up of a larger nucleus into smaller parts. Stability varies between isotopes: the isotope U-235 is much less stable than the more common U-238.

Nuclear energy is released by three exoenergetic (or exothermic) processes:

• Radioactive decay, where a neutron or proton in the radioactive nucleus decays spontaneously by emitting either particles, electromagnetic radiation (gamma rays), neutrinos (or all of them)
• Fusion, two atomic nuclei fuse together to form a heavier nucleus
• Fission, the breaking of a heavy nucleus into two (or more rarely three) lighter nuclei

References

1. ^ "Marie Curie - X-rays and Uranium Rays". aip.org. http://www.aip.org/history/curie/resbr1.htm. Retrieved 2006-04-10. 
2. ^ Turning Lead into Gold

External links

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