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Q. |
What is a “nuclear
weapon”? |
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The term ‘nuclear weapon’
refers to any weapon that utilizes energy
released from nuclear reactions such
as fission/fusion for destructive purposes.
Nuclear weapons can be largely categorized
according to the type of nuclear reaction
involved: nuclear fission (atomic bombs)
and nuclear fusion (hydrogen bombs).
Advancement of technology has also given
birth to the neutron bomb, which utilizes
the massive neutron radiation released
during nuclear fusion in order to set
off a second reaction of nuclear fission.
Atomic
Bombs
The nuclei of U235 (Uranium 235), Pu239
(Plutonium 239), and U233 are called
‘fissile’ materials, because they can
be used to set off nuclear fission when
bombarded by neutrons. When nuclear
fission occurs, a large amount of energy
and neutrons are released. Therefore,
when a certain mass of fissile materials
is concentrated at a single spot, a
chain reaction of nuclear fission can
be set off. The mass at which this is
possible is known as the ‘critical mass.’
An atomic bomb is essentially a set
of several compartments of sub-critical
masses of fissile materials, which are
then rapidly combined at the time of
detonation. The combined materials then
reach a super-critical mass, setting
off a rapid chain reaction that releases
massive amounts of energy within a short
interval of time. Hydrogen
Bombs
Hydrogen bombs utilize the energy released
from the nuclear fusion of light nuclei
such as deuterium and tritium, both
isotopes of hydrogen. Because fusion
only takes place under temperatures
exceeding several million degrees centigrade,
prior detonation of a fission bomb is
required to fire the nuclear fusion
of a hydrogen bomb. Therefore, both
fission and fusion take place during
the detonation of a hydrogen bomb.
Neutron
Bomb
Neutron bombs utilize the massive amounts
of neutron radiation that are released
during nuclear fusion to fire a second
round of nuclear fission. Thus, it is
called the 3F (fission -> fusion
-> fission) bomb. The residual radioactive
materials generated during the two stages
of fission, dubbed ‘ashes of death’,
have earned this bomb the nickname ‘dirty
hydrogen bomb’. |
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Q. |
What are nuclear materials? |
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Nuclear materials are
materials that may be used as nuclear
fuel. Generally, uranium, plutonium,
thorium, or a combination of these is
used as nuclear fuel. In the context
of nuclear weapons development, the
term ‘nuclear materials’ refers to uranium
and plutonium. Uranium
In 1789, German scientist M.H. Klaproth
discovered uranium as a part of the
mineral uraninite (pitchblende) and
named it after Uranus, the planet of
the solar system discovered in 1781.
A total of 14 artificial isotopes ranging
from U227 to U240, all of them radioactive,
are currently known. Three isotopes:
U234, U235, and U238, all of which have
long half-lives, occur in nature. However,
more than 99% of these are U238. Uranium
ore is mined in Canada, the Republic
of South Africa, the United States,
Russia, and Australia. A sustained chain
of nuclear fission reactions releases
massive amounts of energy. This process
is known as nuclear power generation.
Atomic bombs follow the same principle,
but in a much more highly concentrated
setting. It is U235 that is used in
nuclear power generation, with one gram
of uranium 235 yielding the same amount
of energy as three tons of coal. However,
as its natural concentration is barely
0.7%, uranium ore must first be enriched
in order to have a high content of pure
U235. 15kg of U235 is needed to fabricate
one atomic bomb. Plutonium
Plutonium is an artificial element first
synthesized in 1940 by U.S. scientists
G.T Seaborg, E.M. MacMillan, and J.W.
Kennedy by bombarding uranium with deuterium.
It was known to not occur naturally,
but in 1942 a small amount of plutonium
was found contained in uranium ore.
Similar to the processes within a nuclear
power reactor, it seems uranium contained
within minerals absorbs neutrons to
produce plutonium. Taking on a silvery-white
appearance, plutonium is an important
fuel material in nuclear fission, and
therefore a key ingredient in atomic
and hydrogen bombs. International inspection
of the manufacturing of plutonium intensified
dramatically after 1974, when India
extracted and enriched plutonium generated
from a civilian nuclear power reactor
to create and successfully detonate
an atomic bomb. Five to ten kg of highly-enriched
plutonium can be used to fabricate one
atomic bomb. There is controversy concerning
the use of plutonium as an energy source,
due to its potential application in
nuclear weapons as well as the serious
health hazards presented by the element.
Highly carcinogenic, when introduced
into the human body, plutonium is among
the most toxic materials known to man.
Heated debate over its use as an energy
source continues to this day. |
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Q. |
What is HEU (Highly
Enriched Uranium)? |
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A. |
HEU is an artificial
material synthesized by concentrating
U235, which is used in nuclear fission.
Natural uranium ore contains only about
0.7% of pure U235, so its level of concentration
must first be increased before it can
be used as a nuclear fuel. This process
is known as enrichment, which involves
gradually concentrating U235 several
times over. Methods for producing HEU
include gas diffusion, centrifuge processing,
and laser processing. Details of such
methods are highly classified, according
to nuclear nonproliferation guidelines.
A three to five percent concentration
of U235 within the nuclear reactor is
needed for a sustained chain of nuclear
fission. Meanwhile, HEU usually refers
to materials with a 20% or higher concentration
of U235. Therefore, it is natural to
regard a nation holding HEU as harboring
intentions to develop nuclear weapons. |
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Q. |
How are nuclear power
generation and weapons development interlinked? |
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A. |
Using nuclear reactions
to generate electric power and developing
nuclear weapons follow the same scientific
process, using the same materials. Therefore,
nuclear power generation for peaceful
purposes can always be used for wartime
purposes. That is, nuclear fuels used
for power generation can be collected
and then be reprocessed to yield ingredients
of nuclear weapons. (☞ nuclear reprocessing) This is the
very reason the international community
is bent on monitoring the usage of nuclear
materials. (☞ NPT, IAEA) |
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Q. |
What is nuclear reprocessing? |
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A. |
Once ignited, conventional
fuels such as oil or coal keep burning
as long as oxygen is present. However,
nuclear fuels can combust only inside
special equipment: nuclear reactors.
Also, while conventional fuels can only
be used once, nuclear fuels can be used
as fuel several times by being re-enriched.
Therefore, used nuclear fuel can either
be disposed of or re-enriched for repeated
use. This is called reprocessing. Because
nuclear fuels emit radiation, the disposal
of nuclear fuels requires special equipment
to contain the radiation. Also, special
facilities are needed in order to reprocess
nuclear fuels for further use. Such
reprocessing facilities are strictly
regulated and inspected by the international
community. This is because reprocessing
facilities are able to produce plutonium
and HEU, which can be used as ingredients
of nuclear weapons. Used peacefully,
reprocessing facilities are productive.
However, if used for warlike purposes,
these facilities are capable of causing
catastrophic destruction. This is why
South Korea (Republic of Korea) has announced
that it will not build or operate reprocessing
facilities, following its stated commitment
to being a non-nuclear weapons state. |
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Q. |
What is the nuclear-fuel
cycle? |
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A. |
The nuclear-fuel cycle refers to the
process of burning nuclear fuels in
a reactor and then recovering re-usable
materials from spent fuel. The process
involves refining and extracting nuclear
fuels such as uranium and thorium from
mineral ore, burning the fuel in nuclear
reactors, and then finally reprocessing
the spent fuel for further use. Natural
uranium ore contains only 0.7% of the
fissile material U235, which can be
used for nuclear fission. The remainder
of the ore usually consists of U238.
When used in a reactor, U238 absorbs
neutrons to produce Pu239, which is
a fissile material. While Pu239 is an
ingredient of the atomic bomb, it is
also stored for future use in integral
fast reactors. As not all of the U235
is burned up during the power generation
process in reactors, used fuel can be
reprocessed and manufactured to produce
nuclear fuel. While completing the nuclear-fuel
cycle has many economic advantages in
that it secures a stable supply of fuel
for nuclear power generation purposes,
it also has the effect of accumulating
the ingredients of nuclear weapons.
Therefore, nations that complete the
nuclear-fuel cycle are closely watched
by the international community. |
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Q. |
What is the Nuclear
Club? |
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A. |
The Nuclear Club refers
to the five nations that have been approved
by the international community to possess
nuclear weapons: the U.S., the U.K.,
France, Russia, and China. Naturally,
the Nuclear Club is not a formal organization.
Nations not belonging to the Club are
prohibited by international law from
developing or holding nuclear weapons.
Nations such as India, Pakistan, and
Israel are regarded as de facto nuclear
weapon states, despite the lack of official
announcements or approvals. Therefore,
a total of eight nations are believed
to possess nuclear weapons. The Republic
of South Africa was formerly a nuclear
weapons nation. Nations such as Kazakhstan,
Uzbekistan, and Belarus, which gained
independence as well as nuclear capabilities
following the fall of the USSR, have
ceded all nuclear weapons to Russia
and are being closely monitored by the
international community. The members
of the Nuclear Club, in order to prevent
non-nuclear weapons nations from gaining
nuclear weapons capabilities, have organized
the IAEA (☞ International
Atomic Energy Agency) to carry out
on-site inspections on the use of nuclear
materials by non-nuclear weapons states.
Also, the Nuclear Club nations drew
up the NPT (Nuclear Nonproliferation
Treaty), which prohibits non-nuclear
weapons nations from acquiring or developing
nuclear weapons. Meanwhile, some nations
that have not been officially approved
to hold nuclear weapons are critical
of the current unbalanced structure
and are continually striving to acquire
nuclear weapons capabilities. (☞ Current Nuclear Weapons Nations of the
World) |
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Q. |
NPT (Nuclear Nonproliferation
Treaty) |
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A. |
The official name of
the NPT is the ‘Treaty for the Nonproliferation
of Nuclear Weapons’. It prohibits the
five ‘nuclear weapons nations’ from
providing any form of support or transfers
that may contribute to ‘non-nuclear
weapons nations’ gaining nuclear weapons
capabilities, while also prohibiting
non-nuclear weapons nations from developing,
assembling, testing, or acquiring nuclear
weapons. The basic aim of the NPT is
to limit the number of nations with
nuclear weapons capabilities. In accordance
with this goal, non-nuclear weapons
nations are obliged to sign a safeguards
agreement that stipulates duties such
as receiving IAEA inspections on nuclear
materials and their usage. Only the
U.S. and the Soviet Union originally
held nuclear weapons. However, France
and China started testing nuclear weapons
from 1960, which became a trend in other
nations as well. This led to the sentiment
that the trend could very well bring
about the extinction of humanity. A
draft of the NPT was drawn up after
negotiations by the U.S. and the Soviet
Union, and the NPT was opened for signing
following negotiations with non-nuclear
weapons nations at the U.N. General
Assembly on the 12th of June, 1968.
The NPT finally entered into force in
\ March of 1970. Most of the world’s
sovereign nations have ratified the
treaty. However, nations, including
France and China, who opposed the U.S.-
and Soviet-led nature of the treaty
from its inception, have not ratified
it. Other nations such as India, Pakistan,
Israel, and Cuba also have not ratified
the NPT. South Korea
officially ratified the treaty on the
23rd of April, 1975. While North Korea
did sign the treaty in December of 1985,
it withdrew in 1993 in protest of special
nuclear inspections, only to suspend
this withdrawal shortly thereafter.
In January of 2003, North Korea again withdrew
from the NPT as tensions over its nuclear
weapons program intensified. |
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Q. |
IAEA (International
Atomic Energy Agency) |
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A. |
The IAEA is an international
organization whose stated objective
is to limit the use of nuclear energy
to purposes serving the well being of
humanity. It was first proposed by U.S.
president Eisenhower at the eighth U.N.
General Assembly held on the 8th of
December, 1953.
A statute was signed in 1956 by 80 nations,
and the IAEA was finally established
on the 29th of July, 1957. The IAEA
aims to limit the use of nuclear energy
to purposes contributing to the peace,
well being, and prosperity of mankind
while prohibiting its use for any military
purposes. In accordance with such goals,
it pursues such activities as: △promoting
the peaceful use of nuclear energy,
△setting health security guidelines,
△providing underdeveloped nations with
technological aid, △exchanging scientific
and technological information and personnel,
and △building and maintaining radioactivity-safe
facilities. As stipulated by NPT regulations,
the IAEA signs safeguards agreements
with member nations and then conducts
inspections, monitoring, and maintenance
in these nations. Although the IAEA
promotes U.N. policies and also submits
reports to the world body, it is not
an official affiliate organization of
the U.N. South Korea became an IAEA member
nation in 1957, and North Korea in 1974.
The IAEA’s headquarters are located
in Vienna, Austria. |
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Q. |
Nuclear Inspections |
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A. |
The term ‘nuclear inspection’
refers to inspections and related activity
on the current status of nuclear materials
and facilities, which are carried out
by the IAEA in nations that have ratified
the NPT. Inspections usually fall into
three categories: temporary, regular,
and special. Temporary
Inspection: Temporary inspections are
held in order to verify the current
status of the nuclear materials and
facilities as reported by NPT member
nations to the IAEA. Regular
Inspection: Regular inspections are
held periodically in order to update
and account for changes in the status
of a nation’s nuclear materials and
facilities, and are only carried out
when a nation’s report has been verified
through temporary inspections. The inspection
includes the compiling of an inventory
of nuclear materials and the testing
of sealant and security devices. Regular
inspections are carried out three to
four times a year. Special
Inspection: Special inspections are
ordered when temporary and regular inspections
are deemed insufficient to dissolve
suspicions of a nation’s possession
of nuclear weapons. That is, if a nation
declines to modify its report despite
discrepancies discovered during temporary
inspections or if sufficient evidence
to suspect illicit usage has been gathered
through regular inspections, a special
inspection is carried out in order to
ascertain the status of nuclear weapons
development or possession. A representative
case is the special inspection the IAEA
requested of North Korea in 1992. This
happened because, contrary to North Korea
report that it had extracted only 90
grams of plutonium, inspections revealed
sufficient evidence to suspect that
several kilograms of the material had
been extracted. In resistance to the
move by the IAEA, North Korea withdrew
from the NPT in 1993, sparking the 1st
North Korean nuclear crisis. |
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