nuclear weapons
The use of nuclear weapons to end World War II n 1945 forever changed how the public would look at nuclear energy. For much of
the cold war era, many feared a nuclear war that would destroy the world. Created by either breaking up heavy atoms like uranium
into lighter atoms (fission) or joining such light atoms as hydrogen into heavier atoms (fusion), nuclear energy was unique to the last
half of the 20th century. When harnessed correctly, it can produce major changes in electric power generation, medicine, and
warfare. Public fear over the use of nuclear weapons, however, has often stymied nuclear energy's more positive pursuits.
The creation of nuclear energy is based on a few complex concepts. Atoms are the smallest subdivision of matter that have
identifiable physical and chemical properties. However, atoms are actually composed of a nucleus, which itself is made of protons
and neutrons, and an outer shell containing electrons. Nuclear energy originates from processes involving the protons and neutrons
in the nucleus, while physical and chemical processes originate from the electrons in the outer shell.
An element is a material that is made of only one kind of atom; therefore, all the atoms in the element have the same number of
protons in their nucleus. However, the number of neutrons in each atom may vary, which creates isotopes of the element that are
identical chemically but act differently in nuclear processes. An example is hydrogen, which always has one proton, but it can have
from zero to two neutrons, each variant being a different isotope.
Multiple isotopes exist for every element, but not all are stable, which means that some isotopes can change to other isotopes over
time. Some isotopes will discard neutrons to become lighter isotopes of the same element in a process called radioactive decay.
Other isotopes, usually very heavy ones, will discard large numbers of protons and neutrons to become isotopes of a lighter element
in a process called fission. Still other isotopes, usually very light ones, will combine under extremely high temperatures to form
heavier isotopes of other elements in a process called fusion. All nuclear processes release radiation while the isotopes are
changing, which can be very harmful to living organisms.
Early in the 20th century, scientists demonstrated that the nucleus of an atom could decay in some circumstances, which accounted
for the radiation emanating from such naturally radioactive materials as radium and uranium. They also showed that the radiation
came from individual nuclei that shed protons and neutrons to become different isotopes.
During the same time, physicist Albert Einstein proposed a complex theory about space and time that included the formula E=MC 2
(energy equals mass times the speed of light squared), which showed quantitatively how much energy would be released from each
kind of decay. A worldwide effort to understand nuclear processes and to harness the released energy led in 1934 to the discovery
that splitting an atom of uranium with a neutron caused the atom to fission. The fission released large amounts of energy and
caused two more neutrons to fission other uranium atoms in a process called a chain reaction. The discovery triggered several
projects to develop practical uses of the released energy, mostly for bombs.
By 1942, with World War II under way and widespread U.S. fears that Germany would develop nuclear weapons first and change
the course of the war, a consortium of scientists encouraged the U.S. government to launch a major program to develop a new type
of bomb based on the fission process—an atomic bomb. The resulting effort, known as the Manhattan Project and led by physicist J.
Robert Oppenheimer, was given high priority and almost unlimited funding to design and build the world's first atomic bomb. To
reduce the risk of failure, the project simultaneously developed two types of bombs based on the radioactive isotopes of either
uranium 235 or plutonium 239. Both proved to be successful.
Also in 1942, Enrico Fermi and other scientists at the University of Chicago gave the project its first success by initiating a chain
reaction in a nuclear reactor: they caused naturally radioactive uranium to fission in a controlled way. A nuclear reactor is a vessel
that in its core contains fuel elements to provide fissionable material, control rods to absorb neutrons and slow the fission, and a
moderator to reduce the energy of the neutrons, making them easier to capture in the fission process. Outside the core, reactors
also need a way to extract the heat produced, normally using water, and shields to protect people and the environment from the
radiation.
After the Chicago success, the project grew rapidly. Bomb development and technical leadership centered in Los Alamos, New
Mexico; uranium 235 development took place in Oak Ridge, Tennessee and Paducah, Kentucky; and plutonium 239 development
was under way in Hanford, Washington. In just three years, progress had been so rapid that scientists exploded their first atomic
bomb, based on uranium 235, in July 1945 near Alamogordo, New Mexico.
In August 1945, the United States dropped two atomic bombs on Japan, one on the city of Hiroshima and the other on Nagasaki.
The bombs caused horrible destruction in the two cities but compelled Japan to surrender unconditionally and brought World War II
to an end. Those two attacks remain the only two nuclear bombs actually used in a war, although many bombs were detonated
between 1945 and the 1960s for testing purposes.
During the 1950s, nuclear bomb development focused on fusion bombs, called thermonuclear or hydrogen bombs, rather than
fission bombs, as fusion created far more explosive energy. The fusion process uses extreme temperatures (greater then 10 million
degrees) to force hydrogen isotopes like deuterium to fuse, forming helium, and to release even greater energy than from the fission
process. Although the radioactive fallout from hydrogen bombs is somewhat less than from atomic bombs, damage from the blast is
much worse and covers a much larger area. Many hydrogen bombs were successfully tested during the 1950s.
Not all nuclear weapons are designed for mass destruction. Some weapons, called tactical or theater nuclear weapons, are
designed to be fired from cannons against relatively small military targets. Weapons of this type can be distributed to armies in the
field but are normally held in safe locations until their use has been approved by high-ranking military officials. The major concern
with these weapons is that they can be stolen and sold to terrorist organizations.
Moreover, environmental damage from extensive use of nuclear bombs can be catastrophic for all living things. The first result from
a nuclear explosion is the pumping of huge volumes of dust and vaporized matter high into the atmosphere, where the matter
condenses in a mushroom-shaped cloud. If enough bombs are exploded in a short time, a "nuclear winter" could occur that would
block out the sun for weeks or months.
In addition, much of the material pumped into the atmosphere is radioactive because normal matter that is picked up in the blast is
converted to unstable isotopes, some of which could remain radioactive for many years. As the fallout from radioactive matter
drifting back to earth settles on forests and agricultural areas, plants and animals can ingest the material and thus poison the world's
food supplies.
As more nations acquired nuclear weapons technology, fears of an apocalypse strengthened. In 1980, U.S. president Ronald
Reagan began secret talks with six principal economic partners: Canada, France, West Germany, Italy, Japan, and the United
Kingdom. During those talks, the countries discussed worries about the spread of nuclear weapons technology to potentially
unstable and thus dangerous nations. Of particular concern were the nations of India, Israel, and South Africa. India was constantly
at war with Pakistan; with the presence of nuclear weapons, the conflict could easily escalate to full nuclear retaliation. Similarly,
conflict between Israel and various Islamic neighbors seemed destined to intensify if any of those nations acquired nuclear
technology. Likewise, the nation of South Africa was completely unstable, as apartheid was tearing apart the country. Those
concerns multiplied when Argentina, Egypt, and Iran were found to be secretly collaborating on the Condor II, a medium-range
nuclear weapon system, in the late 1980s.
Consequently, in April 1987, the United States, Canada, France, West Germany, Italy, Japan, and the United Kingdom announced
the Missile Technology Control Regime (MTCR). This document established criteria for controlling the spread of ballistic and cruise
missile systems. The document consisted of two parts. The first part, Category I, listed all nuclear items and major components that
could deliver a payload of more than 500 kilograms farther than 300 kilometers. The second part, Category II, listed all hardware
and technology that could be modified for nuclear weapon usage. Other European and non-European nations soon ratified the
MTCR: Belgium, Denmark, Australia, Luxembourg, Norway, the Netherlands, and Spain in 1990; Sweden, Finland, and Austria in
1991; Greece, Ireland, Switzerland, and Portugal in 1992; Argentina, Iceland, and Hungary in 1993; South Africa in 1994; Russia
and Brazil in 1995; and Turkey in 1997.
Since the MTCR, other antinuclear organizations and treaties have been established to reduce the threats of nuclear war. The
Strategic Arms Reduction Treaties (START) I and II first transferred all nuclear weapons in the states of the former Soviet Union to
Russia and then set about a reduction process of those weapons. Furthermore, in 1990, per the Two Plus Four Treaty, the former
East German states became the first nuclear weapon-free area by international treaty. Moreover, the Wassenaar Agreement, a
voluntary system to coordinate national controls on exports of conventional arms and dual-use technologies was established in July
1996. Thirty-three nations have now signed that agreement: Argentina, Australia, Austria, Belgium, Bulgaria, Canada, Czech
Republic, Denmark, Finland, France, Germany, Greece, Hungary, Ireland, Italy, Japan, Luxembourg, the Netherlands, New
Zealand, Norway, Poland, Portugal, Romania, Russia, Slovakia, South Korea, Spain, Sweden, Switzerland, Turkey, Ukraine, the
United Kingdom, and the United States.
Despite those achievements, worldwide nuclear weapon disarmament probably will not occur in the foreseeable future. The
consensus of most countries is that some nuclear weapons must be kept as a deterrent and for self-defense. Thus, limitations on
nuclear technology activity are at present the only measures standing between us and a nuclear apocalypse.
References:
Bernards, Neal, Nuclear Power, 1990; Dawson, Frank G., Nuclear Power: Development and Management of a Technology, 1976;
Joeck, Neil, Maintaining Nuclear Stability in South Asia, 1997; Karawann, Ibrahim A., The Islamic Impasse, 1997; Murray, Raymond,
Nuclear Energy, 1993; Pikayeu, Alexander A., Lenard S. Spector, Elina V. Kinichenko, and Ryan Gibson, Russia, the U.S. and the
Missile Technology Control Regime, 1998; Tertrais, Bruno, Nuclear Policies in Europe, 1999; Wolfson, Richard, Nuclear Choices: A
Citizen's Guide to Nuclear Technology, 1993; Yost, David S., The U.S. and Nuclear Deterrence in Europe, 1999.
"nuclear weapons." World History: The Modern Era. 2007. ABC-CLIO. 15 May 2007 <http://www.worldhistory.abc-clio.com>.