CRITICAL
ISSUES FORUM
BENCHMARK
I
Topic:
ÒNuclear Renaissance: Risk versus BenefitsÓ
Students:
Georgy Koshelev, Andrew Popov
Form
10
Gymnasia
# 41
Teacher:
Helen Patrusheva
Teacher
of English
Gymnasia #41
Novouralsk
Sverdlovsk region
Russia
2008
Benchmark
I
"No
energy is more expensive than no energy"
Dr Homi Bhabha, Indian physicist
Objective
1
In this part of our research
work we are going to show our understanding of energy sources in use in the
world today, including renewable and non-renewable ones, as well as to describe
the processes involved in the production of energy in different countries in
the world.
First of all, we will try to
build our own glossary of terms and phrases related to energy sources.
Glossary [8]
Availability - able
to be obtained, used, or reached
Barrel- the
amount held by a barrel (U.S. barrel= 119, 2 liters).
British Thermal
Unit (BTU) -
a standard measure of energy that can be used regardless of the type of energy
being produced.
Energy- scalar physical quantity
that is a property of objects and systems which is conserved by nature.
Energy
availability factor - the percentage of maximum energy generation
Energy consumption
-
the use of energy
as a source of heat or power or as a raw material input to a manufacturing
process.
Energy production - generation of energy in a coal
fired power station, in an oil fired power station, in a nuclear power station,
etc.
Generating station
-
a station that
consists of electric generators and auxiliary equipment for converting
mechanical, chemical, or nuclear energy into electric energy.
Global warming - a gradual
increase in world temperatures caused by polluting gases such as carbon dioxide
which are collecting in the air around the Earth and preventing heat escaping
into space.
Greenhouse effect - warming of
the Earth's surface as a result of atmospheric pollution by gases.
Industrial
revolution - change to industrial methods
of production.
Joule (J) - a unit of amounts of energy (Mega joule (MJ) =
106 Joules; Gig joule (GJ) =109 Joules).
mbd - million barrels per day.
Nuclear renaissance – renewing of interest in nuclear
energy
OPEC (Organization of Petroleum Exporting
Countries) - a group of
countries which produce oil and decide together how much to produce.
Power - energy that is produced by
mechanical, electrical, or other means.
Power plant - a power station.
Sustainability - causing
little or no damage to the environment and therefore able to continue for a
long time:
Watt (W) – a unit of energy rate (or power), one watt is one
joule per second.
Energy
is essential for providing the development of the world, and mankind progressed
greatly over its history using different sources of energy – from the
first steps in the use of wind and water power to the industrial revolution
based on coal and steam power and still further to the use of nuclear power.
Energy
Sources
Energy can be considered in two categories - primary and secondary.
á
Primary energy is energy in the form of natural resources, such as wood,
coal, oil, natural gas, natural uranium, wind, hydro power, and sunlight.
á
Secondary energy is the more useable forms to which primary energy may
be converted, such as electricity and petrol.
Primary energy can be
renewable or non-renewable:
á
Renewable energy sources include solar, wind energy, biomass, geothermal
energy and hydro power.
á
Non-renewable energy sources include the fossil fuels - coal, oil and
natural gas, plus uranium.
(http://www.uic.com.au/graphics/yu-bike.gif
)
Non-renewable
energy sources
Fossil fuel is a
class of materials of biologic origin occurring within the earthÕs crust that
can be used as a source of energy. Fossil fuels include coal, petroleum and
shale oil. All fossils can be burned to provide heat, which may be used
directly, as in home heating or to produce steam to drive a generator for the
production of electricity. Fossil fuels supply nearly 90% of all the energy use
by industrially developed nations. [1, p.597,
598]
Coal is the most abundant
fossil fuel. According to the International Energy Agency the reserves of coal
are around 909 billion tons, which is enough for 155 years. This was the fuel
that launched the industrial revolution. Coal was the first to be widely used industrially and
to increase people's standard of living. Its reserves are large, the fuel is inexpensive
but there is great concern about pollutants and global warming.
The search for
alternative energy has revived interest in conversion of coal into liquid fuels
similar to oil. Various technologies for economical liquefaction of coal have
been investigated, particularly in oil – dependent countries that have
extensive oil reserves. [1, p. 361]
For further information
about the top ten countries which have the biggest reserves of coal click here.
Petroleum occurs in the earth in liquid
(crude oil), gaseous (natural gas), or solid (bituminous coal, asphalt) forms.
Petroleum and natural gas are the most important primary fossil fuels. Asphalt
has been used since ancient times to caulk ships and pave roads. In the mid
1800s, oil began to replace whale oil in lamps, and the first well specifically
for oil was drilled in 1859. The development of the automobile gave petroleum a
new role as the source of gasoline. Petroleum and its products have since been
used as fuels for heating, for land, air and sea transport, and for electrical
power generation. Crude oil and natural gas,
produced mostly in Saudi Arabia, the U.S. and Russia, now account for about
60% of world energy consumption. At present rates of consumption, the known
supply will be exhausted by the mid 21st century. [1, p. 1254]
For
further information about the top ten countries which have the biggest reserves
of gas all round the world, and the major producers and
consumers of oil.
click here.
Uranium is abundant on Earth,
incorporated into the planet during the planet's formation. Uranium-238 (U-238)
makes up 99 % of the uranium on the planet. U-235 makes up about 0.7 % of the
remaining uranium found naturally. World mine production is about 35,000 tons
per year, but a lot of the market is being supplied from secondary sources such
as stockpiles, including material from dismantled nuclear weapons. Practically, all of it is used
for electricity. [13]
Here you may see the nuclear resources of major countries.
Energy Wastes
Any means of producing
electricity involves some wastes and environmental hazard. The enormous
difference in the quantities of fuel used directly affects the quantities of
waste that remain after the electricity has been generated.
(http://www.world-nuclear.org/images/education/yu-fuel.gif )
The 1,000 MWe coal-fired power
station produces about 7 million tons of carbon dioxide each year, plus perhaps
200,000 tons of sulfur dioxide which in many cases remains a major source of
atmospheric pollution. Other waste products from the burning of coal include
large quantities of fly ash (typically 200,000 tons per year), containing toxic
metals, including arsenic, cadmium and mercury, organic carcinogens and
mutagens (substances that can cause cancer and genetic changes) as well as
naturally-occurring radioactive substances.
If not fully contained, these routine wastes can cause
environmental and health damage even at great distances from the site of the
power station.
As
far as the nuclear energy is concerned, it should be noted that it takes full
responsibility for the disposal of all its wastes and meets the full cost of
doing so. Nuclear energy today saves the emission of about 2.4 billion tons of
carbon dioxide each year (compared with over 7 billion tons per year actually
emitted from fossil fuel electricity generation).
The
difference in the heat value of uranium compared with coal and other fuels is
important (though both are used at about 33% thermal efficiency in the power
station). A one million kilowatt (1,000 MW) power station consumes about 3.1
million tons of black coal each year, or about 24 tons of uranium (as UO2)
enriched to about 4% of the useful isotope (U-235). This requires the mining of
over 200 tons of natural uranium which may be recovered from, say, 25-100,000
tons of typical uranium ore. [8]
Electricity
generation - the future fuel mix
For most countries the questions that need to be answered are:
What are our likely electricity requirements? What forms of generation are available
to us? Which combination will affordably provide our needs with maximum
security and the least harm to our population and environment?
As
gas prices rise and coal faces the prospect of economic constraints on its
emissions, nuclear energy looks increasingly attractive. The cost of fuel for a
nuclear power station is much less than for an equivalent coal fired power
station. Electricity from nuclear reactors in many regions is competitive with
electricity produced from coal, even after providing for management and
disposal of radioactive wastes and the decommissioning of reactors.
In
mid 2001, there were 31 countries of varying size, political persuasion and
degree of industrial development, which included nuclear power in their energy
mix and were operating nuclear reactors. Over 16% of the world's electricity is
being produced by more than 440 reactors, with 30 more under construction.
Belgium, China, France, Germany, Hungary, India, Japan, Russia, Switzerland, UK
and USA are just some of the countries with major nuclear energy programs.
In
2000 there was as much electricity produced from nuclear energy as from all
sources worldwide in 1961 (2438 billion kilowatt-hours).
In
2006 China, India, Japan, Pakistan, the Russian Federation, the Republic of
Korea, the U.K. announced plans for significant expansion. Estonia, Lithuania
and Latvia launched a joint study for a nuclear power plant to serve all three
countries. Belarus, Egypt, Indonesia, Nigeria and Turkey announced which steps
they were taking toward their first nuclear power plants. [6, p. 1]
No
country would want to be too dependent on a single energy source. For many it
is therefore not a question of coal or nuclear for their main supply of
electricity, but a combination of both, with as much help as possible from
renewable sources, and back-up from gas.
The
twentieth century saw a rapid twenty fold increase in the use of fossil fuels
supplying 81,8% of the world's energy. In this diagram you may see the consumption of different
resources in todayÕs energy system.
The diagram shows the high worldwide
reliance on fossil fuels in supplying primary energy and producing electricity. But:
1. There is a limited amount of fossil fuel. It is not "renewable" and
there is no known way to make more.
2. The use of fossil fuels as
energy source is a major reason of atmospheric pollution, global warming and
health damage.
3. Oil and natural gas
resources are concentrated among relatively few suppliers and this is the
question of the security of energy supply.
http://www.readinga-z.com/newfiles/levels/z/energysourcesz.html
The challenge today is to move away from heavy
dependence on fossil fuels and utilize other energy resources more fully. It is necessary to
develop advanced, cleaner, more efficient, affordable and cost-effective energy
technologies such as renewable and nuclear power.
Renewable
resources
Renewable resources are
available each year, unlike non-renewable resources which are eventually
depleted. Most of earth's available energy resources are renewable resources.
In 2004, renewable energy
supplied around 7% of the world's energy consumption. The renewable sector has
been growing significantly since the last years of the 20th century, and in
2005 the total new investment was estimated to have been 38 billion US dollars.
Germany and China lead with investments of about 7 billion US dollars each,
followed by the United States, Spain, Japan, and India. This resulted in an
additional 35 GW of capacity during
the year. [14]
Hydropower
Hydropower is the force of moving
water. The energy of moving water is captured for some useful purposes. Electricity
is produced from generators driven by water turbines that convert the energy in
falling or fast – flowing water to mechanical energy.
The advantages of
hydroelectric power are that it is continually renewable and produces no
pollution. Norway, Sweden, Canada and Switzerland rely heavily on
hydroelectricity because they have industrialized areas close to mountainous
regions with heavy rainfall. The U.S, Russia, China, India and Brazil get a
much smaller proportion of their electric power from hydroelectric generation. [1, p. 784]
On the 1 of February, 2008 the
News of the channel ÒRussiaÓ showed a remote Caucasian village in Russia where
the villagers using their Know – How had built a hydropower station to
supply their particular village with electricity. One more hydropower station
is going to be built in the same way in a neighboring area. The fact proves
that the ceaseless water power can be used comparatively easily.
http://www.worldenergy.net/about_us/company_philosophy.php
Biomass
and bio fuels
Until the end of the
nineteenth century biomass was the predominant fuel. Soy diesel and corn-based
ethanol can profitably supplant fossil fuels. Advances using easily grown
perennials like switch grass, hemp, kudzu, algae and a wide range of trees and
weeds make bio-fuels even cheaper and cleaner. The use of biomass fires for
cooking is excluded.
Electricity produced from
biomass sources was estimated at 44 GW for 2005. Biomass electricity
generation increased by over 100% in Hungary, the Netherlands, Poland, Spain
and Germany. The
Renewable Energy Sources Act of 21.July 2004 was amended on the 1.August 2004
by the German Federal Government.
The
particular aims of the amended EEG are to increase the share of Renewable
Energies in the total electricity supply to at least 12, 5% by the year 2010.
It
regulates which materials may be classified as biomass, which technical
processes for the generation of electricity fall under the law for renewable
energies (EEG) and which environmental regulations apply for the generation of
energy from biomass. [23]
220 GW
was used for heating in 2004, bringing the total energy consumed from biomass
to around 264 GW. World production of bio ethanol increased by 8% in 2005
to reach 33 billion liters (8.72 billion US gallons), with most of the increase
in the United States, bringing it level to the levels of consumption in Brazil.
Bio diesel increased by 85%
to 3.9 billion liters (1.03 billion US gallons), making it the fastest growing
renewable energy source in 2005.
Wind power
Wind
power is the
conversion of wind energy into useful form, such as electricity, using wind turbines. In windmills, wind
energy is directly used to crush grain or to pump water. Windmill use became
increasingly widespread in Europe , particularly the Netherlands, from the 12th
century to the early 19th century. Though wind is irregular and
spread out, it contains tremendous amounts of energy. The use of wind –
energy systems grew considerably in the 1980s and; 90s. Germany today produces
more wind energy than any other country. Some 15,000 wind turbines are now in
operation in California. [1, p. 1751]. Wind energy is plentiful, widely
distributed, and clean, it reduces greenhouse effect.
Although wind currently
produces just over 1% of world-wide electricity use, it accounts for
approximately 19% of electricity production in Denmark, 9% in Spain and
Portugal, and 6% in Germany and the Republic Ireland (2007 data). Globally,
wind power generation more than quadrupled between 2000 and 2006.
On February,12 program
ÒEventsÓ on channel TVC showed some farmer families from far remote area in
Khabarovsk region. The families have built a windmill. They use wind and solar
energy for farming and they are satisfied with it.
Solar power
Solar
energy is
radiation from the sun that can produce heat, generate electricity, or call chemical
reactions. Solar energy is inexhaustible and nonpolluting, but it is not an
efficient energy source, since earthÕs atmosphere absorbs or scatters over 50%
of incoming solar radiation. Solar cells convert solar radiation directly into
electricity by means of the photoelectric effect.
There are two ways of
solar heating: active and passive. Passive heating relies on architectural
design. The buildingÕs siting, orientation, layout, materials, and construction
are utilized to maximize the heating effect of sunlight falling on it. A well
– insulated building with a large south – facing window can trap
heat on sunny days and reduce reliance on gas, oil, or electricity. Brick,
stone, or tile capacity walls are often incorporated to absorb the sunÕs energy
and radiate it into the interior, usually after a time lag of several hours.
In active solar heating,
mechanical means are used to collect, store and distribute solar energy. In
liquid – bases systems, a blackened (everybody knows how hot it is to
wear black clothes on a sunny day) metal plate on the exterior absorbs sunlight
and traps heat, which is transferred to a carrier fluid to produce stem to run
a generator. The system can supply a home with hot water from the tank or
provide space heating with the warmed water flowing through tubes in floors and
ceilings. [1,
p. 1507 – 1508]
Solar energy technologies
harness the sun's energy for practical ends. These technologies date from the
time of the early Greeks, Native Americans and Chinese, who warmed their
buildings by orienting them toward the sun. Modern solar technologies provide
heating, lighting, electricity and even flight.
Japan
and Germany are now the largest consumers of photovoltaic cells in the world
despite their unfavorable geographic locations
Geothermal
Power is obtained by
using heat from the earthÕs interior. Most geothermal resources are in regions
of active volcanism. Hot springs, geysers, pools of boiling mud, and fumaroles
are the most easily exploited sources. The Ancient Romans used hot springs to
heat baths and homes, and similar uses are still found in Iceland, Turkey, and
Japan. Geothermal energy is used
commercially in over 70 countries. Geothermal energyÕs greatest potential lies
in the generation of electricity. It was first used to produce electric power
in Italy in 1904. [1, p. 646 – 647]
With the urgent
need to find energy sources that are renewable and don't emit greenhouse gases,
geothermal energy is ideal — "the best renewable energy source
besides the sun," Mack Kennedy from the Department of Energy's Lawrence Berkeley National Laboratory says. [23] Accessible
geothermal energy in the United States, excluding Alaska and Hawaii, has been
estimated at 9 x 1016 (90 quadrillion) kilowatt-hours, 3,000 times more than
the country's total annual energy consumption. Determining helium ratios from
surface measurements is a practical way to locate some of the most promising
new resources.
Geothermal technology
uses superheated steam from the Earth's core to create energy in more than 20
countries worldwide. The steady 55-degree heat of the Earth's crust also works
the building of homes and offices, including large urban skyscrapers. This
nature-based technology provides valuable supplemental heat in winter and
base-line cooling in summer
For further information you may click here.
á
Solar energy
á
Wind power
á Geothermal
http://www.economist.com/world/britain/displaystory.cfm?story_id=10024594
Alternative energy
paths
Alternatives
to fossil fuels represent low carbon dioxide sources of energy. But they are
not yet economically competitive with conventional sources. Over the
next 30 years, they will become an increasingly important part of the
worldÕs energy solutions. There is an example of measures which the famous oil
company Shell undertakes to find alternative energy paths. Shell is the largest distributor of bio
- fuels, and one of the biggest investors in wind energy, as well as an
investor in second-generation bio - fuels, thin-film solar cells and hydrogen.
Shell is involved in the development and
production of CIS thin film
technology, which converts the sunÕs power into electricity.
Sited in the North Sea, ShellÕs first offshore wind farm
provides
enough power to supply more than 100,000
homes.
Shell is developing cost-effective new
technologies and solutions
for capturing and storing carbon dioxide safely underground.
Shell is developing new biofuels by
converting waste biomass such
as woodchips and straw into cellulose ethanol.
Shell Hydrogen is exploring how hydrogen-related
technologies and
applications can potentially reduce transport emissions and increase
energy security.
In
the twenty first century, some of these different energy paths might become
more mainstream and start replacing the fossil fuels. They and
may grow to supply around one-third of the worldÕs demand for energy by
2050.
Energy
consumption
Since the advent of the
industrial revolution, the worldwide energy consumption has been growing
steadily. In 1890 the consumption of fossil fuels roughly equaled the amount of
biomass fuel burned by households and industry. In 1900, global energy
consumption equaled 0.7 TW (=1012 Watt.)
The
twentieth century saw a rapid twenty fold increase in the use of fossil fuels.
Between 1980 and 2004, the worldwide annual growth rate was 2%. According to
the US Energy Information Administration's 2006 estimate, the estimated 15TW
total energy consumption of 2004 was divided as follows, with fossil fuels
supplying 86% of the world's energy:
Fuel type Power
in TW Energy/year
in EJ
Oil 5.6
180
Gas 3.5
110
Coal 3.8
120
Hydroelectric 0.9
30
Nuclear 0.9
30
Geothermal, wind,
solar, wood 0.13
4
Total 15
471
Source: http://en.wikipedia.org/wiki/World_energy_resources_and_consumption
Here you may see changes in sources of energy in the past
100 years.
Mankind
experiences lack of energy. The population of our planet is constantly increasing: every ten years
– by an average of 1 billion people and because of it the humanity needs
more and more energy to maintain the necessary standard of living. People need
and will need energy for agricultural and industrial aims.
The growth of population is accompanied by the growth of water consumption.
Transport takes a great part
in energy consumption. In China, for example, there are 9 cars for every 1,000
eligible drivers. In India, there are 11 cars/1,000. In the U.S., there are
1,148 cars/1,000. The figures are quite different in different countries. The
Chinese, for example, try to reduce energy consumption and air pollution at the
same time by using cars with even numbers on even dates, and cars with uneven numbers
on uneven dates.(October, 2007. TV Channel ÒRussiaÓ, the News)
In
the modern world energy for household is considered to be one of the
necessities. Our homes are stuffed with a lot of household gadgets. In our
school we organized a survey. A big group of students of different ages was
asked to name the number of different household appliances in their homes.
These studentsÕ parents were also asked to answer our questions. The parents
had to name the household appliances they had had in their homes when they were
the same age as their children are now.
Some of the happy participants are on the photos here. The results of the studentsÕ
answers are in Diagram 1. The results of the parentsÕ
answers are in Diagram 2. The difference is quite
obvious. We consume much more energy in our homes than 25 years ago. [25]
What
is
?
It is a measure of the impact human activities have on the environment in
terms of the amount of green house gases produced, measured in units of carbon
dioxide.
This
table gives an idea of which appliances in our household are contributing the
most to our carbon footprint.
|
Appliance |
Usage |
Per Use |
Cost per year |
kg CO2 per year |
|
Microwave Oven |
96 times per year |
0.945 kWh per use( based on
1.39 kWh for full power and 0.5 kWh for defrosting) |
£9.07 |
39 |
|
Washing
Machine |
187 washes per year |
EU energy label A-rated
gives an average consumption at 40¡C using a 2kg load to be 0.63 kWh |
£11.78 |
51 |
|
Electric
Tumble Dryer |
148 uses per year |
2.50 kWh per cycle |
£37.00 |
159 |
|
Electric
Oven |
135.1 uses per year |
1.56 kWh per use |
£21.08 |
91 |
|
Dishwasher
at 65¡C |
135 uses per year |
1.44 kWh per use |
£19.44 |
84 |
|
Fridge-Freezer
A spec |
24 hours a day |
408 kWh per year |
£40.80 |
175 |
|
Standard
Light Bulb |
4 hours a day |
100 W |
£14.60 |
63 |
This table compares the various types of televisions
and digital adapters, including on standby mode.
|
Appliance |
Usage |
Per use |
Cost per year |
kg CO2 per year |
|
Primary
TV – CRT (Cathode Ray Tube) 34-37 inch |
On Power |
198.5 W |
£47.09 |
203 |
|
Primary TV
– LCD 34-37 inch |
On Power |
211.1 W |
£50.08 |
215 |
|
Primary TV
– LCD |
Standby |
1.8 W |
£1.15 |
5 |
|
Primary TV -
Plasma |
Standby |
3.6 W |
£2.30 |
10 |
|
Primary
TV – Rear projection 34-37 inch |
On Power |
192.3 W |
£45.62 |
196 |
Source:
http://www.carbonfootprint.com
Conclusion
Times are changing.
Mankind needs energy but the shortage of energy and the rise of its expenses is
an obvious fact. Mankind is to discover alternatives to traditional energy.
Nuclear
energy has perhaps the lowest impact on the environment-including air, land,
water, and wildlife—of any energy source, because it does not emit
harmful gases, isolates its waste from the environment, and requires less area
to produce the same amount of electricity as other sources.
Environmentalists claim
that nuclear power is not a clean solution to the climate crisis, but instead diverts
scarce resources from the green technologies that really work: renewable,
conservation, and efficiency technologies that can really solve the climate
crisis while also generating wealth, jobs and economic stability. Nevertheless, the choice for new
construction depends on the geographical position and the alternatives
available, on the overall electricity demand in a country and how fast it is
growing, on the market structure and investment environment, on environmental
constraints, and on investment risks due to possible political and regulatory
delay or changes.
Bibliography and
Other Sources
1.
Merriam – WebsterÕs Collegiate Encyclopedia. Springfield, Massachusetts, USA, 2000
2.
Christian
Science Monitor, "In Bid to Cut
Mercury, US Lets Other Toxins Through", USA, 2005.
3.
ÒThe
Economics of Nuclear PowerÓ World Nuclear Association (June 2007).
4.
ÒEnvironmental
impacts of coal power: air pollutionÓ Union of Concerned Scientists, 2005
5.
Gary
Crawley. ÒRisks vs. Benefits in Energy
ProductionÓ, USA, 2006
6.
Nuclear Technology Review. International Atomic Agency. Vienna,
2007.
7.
http://www.technologystudent.com
18.http://www.currentconcerns.c
23.http://www.carbonfootprint.com
25.http://www.carbonfootprint.com
26.http://www.fossil.energy.gov
27. Danilov- Danilyan, ÒIs the water more expensive than oil?Ó, Arguments and Facts,
February 23, 2008, p.19.
BENCHMARK
I
Objective
2
In
this part of our research paper we are going to demonstrate an understanding of
the processes involved in the production of nuclear energy in countries around
the world. We will also describe the nuclear fuel cycle and will show places in
the cycle where diversion of materials could take place. We will begin with
building our own glossary of nuclear terms and phrases.
Glossary [3]
Boiling water
reactor (BWR)- a very common type of light
water reactor in use worldwide. Ordinary water, used as both coolant and
moderator, is allowed to boil in reactor core. The steam produced is then used
to directly generate electricity.
Breeder reactor- a nuclear reactor designed
to produce more fuel than it consumes. Typically these have fertile material
placed in and the reactor core in order to use neutrons produced during fission
to transmute the fertile material into fissile material.
CANDU reactor- CANDU is an acronym meaning
Canadian deuterium uranium reactor. This type of reactor uses ÒheavyÓ water.
Closed fuel cycle - a fuel cycle that
reprocesses spent fuel to recycle the unused fissile material. Once removed
from the reactor the spent fuel is chemically processed to remove the uranium
and plutonium which can then be used to make new reactor fuel.
Control rods- control rods are made of
materials which absorb neutrons, for example boron, silver, indium, cadmium and
hafnium.
Conversion- the chemical process used to
turn solid uranium oxide from a uranium mill into uranium hexafluoride, which
is a gas at certain temperatures and pressures, and therefore suitable for the
enrichment process.
Coolant- a coolant absorbs and
removes the heat produced by nuclear fission and maintains the temperature of
the fuel within acceptable limits.
Critical mass- the amount of fissionable
material needed to maintain a fission chain reaction for a given set of
conditions.
Decommissioning- administrative and technical
actions taken to allow the removal of some or all regulatory controls from a
nuclear installation.
Depleted uranium- uranium having less than the
natural isotopic concentration of uranium-235 of about 0,711%.
Enriched uranium- uranium in which the
isotopic concentration of uranium-235 has been increased above the naturally
occurring level of 0,711%
Enrichment- the physical process of
increasing the isotopic concentration of uranium-235 above the level found in
natural uranium. Two processes are commercially used, gaseous diffusion and gas
centrifugation.
Fast neutrons- fast neutrons are defined as
those with a high kinetic energy above about 0,1 eV.
Fissile material- material that is capable of
fission after the capture of a thermal (slow) neutron.
Fission product- when a nucleus undergoes
fission, it splits into two fragments, release neutrons and a great deal of
energy. The fragments are called fission products.
Fuel- the material uses in the
reactor which, through fission, releases energy.
Fuel cycle- the series of steps involved
in creating, using and disposing of fuel for nuclear reactors.
Fusion- fusion is a nuclear reaction
where light nuclei combine to form more massive with release of energy.
Heavy water- water that contains
significantly more deuterium atoms that normal water.
Highly enriched
uranium-
uranium enriched to at least 20% of uranium-235
Isotope- an element that have the
same number of protons different number of neutrons than original material.
Light water
reactor- a
nuclear reactor type that is cooled and/or moderated by ordinary water, as
opposed to heavy water.
Megawatt- the international unit of
power that is equal 1x106 watts.
Milling- the process through which
mined uranium ore is chemically treated to extract and purify the uranium.
Moderator- a material that slows
neutrons down to the thermal energy range.
Natural uranium -
uranium that has the same isotopic composition as found in nature, 99,2745%
uranium- 238, 0711% uranium-235 and 0,0055% uranium-234.
Neutron- an elementary particle with
no electric charge and mass slightly greater than a proton
found in the nucleus of all atoms except hydrogen-1.
Nuclear reactor- a device that uses the
nuclear fission process to produce energy.
Nuclear
proliferation- the
spread of nuclear weapons, fissile material, and weapons-applicable nuclear
technology and information.
Once- though fuel
cycle- a fuel
that does n0ot recycle the spent fuel. Once removed from the reactor the spent
fuel is conditioned and stored until a disposal repository becomes available
Pressurized water
reactor (PWR)- a nuclear reactor maintained
under a high pressure to keep its coolant water from boiling at the high
operating temperature.
Proton- an elementary nuclear
particle with positive electric charge located in the nucleus of an atom.
Radiation- energy traveling in the form
of high-speed particles or electromagnetic waves.
Reprocessing- the process of treating used
reactor fuel to recover the uranium and plutonium and to separate them from the
fission products and other elements.
Reactor- a device for containing and
controlling a nuclear reaction.
Spent nuclear fuel
(SNF)- fuel
that has been irradiated in and then permanently removed from a nuclear
reactor.
Thermal neutrons- elementary particle with a
low kinetic energy, less than 0,1 electron volt (eV).
Transmutation- a process when a nucleus
absorbs a neutron and changes the nucleus from one element to another.
Tritium- a radioactive isotope of
hydrogen having two neutrons and one proton.
Tail- a remainder of the ore,
containing most of the radioactivity and nearly all the rock material
X-ray- kind of waves which is
emitted by energy changes in an atomÕs electrons.
The
nuclear fuel cycle
(http://www.world-nuclear.org/education/graphics/nfc1-1.gif)
Each
fuel has its own distinctive fuel cycle. Like coal, oil and natural gas,
uranium is an energy resource which must be processed through a series of steps
to produce an efficient fuel for generating electricity. The uranium or
'nuclear fuel cycle' is more complex than the others.
Mining and milling
The first industrial
mining of uranium ore took place in J‡chymov, a silver-mining city in what is
now the Czech Republic. Pitchblende ore from J‡chymov was used by Marie Curie to
isolate the element radium, a decay product of uranium. Until World War II
uranium mining was done primarily for the radium content. The United States was
the world's largest uranium producer in the 20th century because of
the Grants Uranium District in New Mexico. Australia's resources of uranium are about 27% of the
world's total, Canada's 13%.
http://blogs.princeton.edu/chm333/f2006/nuclear/uranium.gif
)
Others
in order are: Kazakhstan (17%), Canada, USA, South Africa, Namibia, Brazil,
Niger and Russia. Many more countries have smaller deposits which could be
mined if needed. Canada is the main supplier of uranium to world markets. [3]
There are two ways of uranium ore mining:
Surface
mining (open cut). Surface mining can leave behind large areas of infertile waste rock
(i.e. it produces 75 % of industrial waste in Spain). [14]
(http://www.cameco.com/common/images/u101/fc_pit.jpg)
Underground
mining. If
the uranium is too far below the surface for open pit mining, an underground
mine might be used with tunnels and shafts dug to access and remove uranium
ore. [14]
(http://www.cameco.com/common/images/u101/fc_dumptruck.jpg
)
Heavy machinery is needed in
mining for exploration and development. Underground mining is more technologically
sophisticated because of the dangers and expense of tunneling.
Some mining methods have
devastating environmental and public health effects. The concentrations of
methane are issues of concern related to safety in mining.
(http://www.cameco.com/common/images/u101/fc_insiturecovery.jpg)
Then,
the mined uranium ore is sent to a mill which is usually located close to the
mine. At the mill the ore is crushed and ground and sulfuric acid is used to
separate from the waste rock.
Milling
produces a uranium oxide concentrate containing more than 80% uranium. The
original ore may contain as little as 0.1% uranium. The remainder of the ore,
containing most of the radioactivity and nearly all the rock material, becomes
tailings. Tailings contain long-lived
radioactive materials, heavy metals, which need to be isolated from the
environment. [14]
Facility
locations. Principal nations involved in
uranium mining and milling are the United States, Australia, Canada, Namibia,
Russia, Niger, Ukraine, Kazakhstan, Brazil, India, China, Argentina and others.
Proliferation
risk. Low. Mining and milling facilities havenÕt got the
potential to be used in producing nuclear weapon.
Uranium conversion
The product of a uranium mill needs additional processing. It is first
refined to uranium dioxide, which can be used as the fuel for those types of
reactors that do not require enriched uranium. Most is then converted into
uranium hexafluoride, ready for the enrichment plant. It is shipped in strong
metal containers. [3]
(http://www.ulba.kz/eng/images/umz3_1_4.jpg)
){kind=link}
Facility
locations. The nations involved in
uranium conversion are the United States, Australia, Canada, Namibia, Russia,
Niger, Ukraine, Kazakhstan, Brazil, India, China, Argentina and others.
Proliferation
risk. Low. Conversion facilities havenÕt
got the potential to be used in producing nuclear weapon.
Enrichment
The enrichment stage is
particularly sensitive: it is the first moment at which uranium takes on the
fissile properties needed for use in a nuclear bomb.
(http://www.nrc.gov/reading-rm/doc-collections/fact-sheets/ole.gif
)
Enrichment is a process designed to raise the share of
the fissile U-235 in uranium from its natural level of 0.7 percent to the 
much higher levels needed for
use in a nuclear reactor or a nuclear bomb. Most civilian power reactors use
enriched uranium fuel containing 3 to 4% U-235. The four most commonly used
uranium enrichment methods are gaseous diffusion, gas centrifuge, aerodynamic,
and laser.
Natural uranium contains 99% U-238 and only about 0.7%
U-235 by weight. [9]
(http://www.nrc.gov/images/materials/fuel-cycle-fac/not-equal.gif )
Historically, most uranium has
been enriched by the gas diffusion method.
Now the gas
centrifuge method is used as the preferred method for enriching uranium. This
method requires only 35 repetitions to achieve weapon-grade uranium. The
technology requires a high level of technical precision, and it is difficult to
maintain. [3]
(http://upload.wikimedia.org/wikipedia/commons/thumb/b/bf/330px-Sellafield-1515b.jpg)
Facility
locations. Principal nations involved in
uranium enrichment are the United States, France, Russia, The Netherlands,
China and the United Kingdom. Nations of proliferation concern that possess an
enrichment capacity include Argentina, Brazil, and Pakistan.
Proliferation
risk. High. Enrichment facilities have
the potential to produce weapons-grade uranium. The high proliferation
potential of the enrichment stage has led Nuclear Suppliers Group (NSG) member
states to place an unofficial embargo on the export of enrichment technology
Fuel
fabrication
Fabrication begins
by pressing powdered UO2 into small cylindrical shapes and baking
them at a high temperature (1600 - 1700¡C) to make hard ceramic pellets. In a
light water reactor, the fuel pellets are packed in thin tubes called fuel
rods. The rods are grouped together into a bundle called a fuel assembly which
is loaded into fuel channels in the reactor core.
(http://www.cameco.com/common/images/u101/fuel_bundle.gif
)
Facility
locations. Principal nations involved in
uranium fuel fabrication are the United States, France, Russia, The
Netherlands, China and the United Kingdom. Nations of proliferation concern
that possess an enrichment capacity include Argentina, Brazil, and Pakistan.
Proliferation
risk. High. Fuel fabrication facilities
have the potential to produce weapons-grade uranium.
Nuclear power generation
Nuclear
Power Plants use a fuel called uranium. Energy is released from uranium when an
atom is split by a neutron. The uranium atom is split into two and as this
happens energy is released in the form of radiation and heat. This nuclear
reaction is called the fission process.
In a nuclear power
plant the uranium rods are kept cool by submerging them in water. When they are
removed from the water a nuclear reaction takes place causing heat. The amount
of heat required is controlled by raising and lowering the rods. Inside a
nuclear reactor the nuclei of U-235 atoms split (fission) and, in the process,
release energy. Some of the U-238 in the fuel is turned into plutonium in the
reactor core. The main plutonium isotope is also fissile and it yields about
one third of the energy in a typical nuclear reactor. [2]
(http://www.technologystudent.com/images7/nucl3.gif )
As with a coal-fired power
plant about two thirds of the heat is dumped, either to a large volume of water
(from the sea or large river, heating it a few
degrees) or to a relatively smaller volume of water in cooling towers, using
evaporative cooling (latent heat). [2]
(http://www.technologystudent.com/images7/nucl2.gif )
Facility
locations. Principal nations involved in
power generation are the USA, Canada, Mexico, Japan, Belgium, Finland, France,
German, Italy, Holland, Spain, Sweden, Switzerland, Great Britain, Bulgaria,
the Czech Republic, Slovakia, Hungary, Romania, Slovenia, Russian Federation,
Ukraine, Armenia, Kazakhstan, Lithuania, China, India, North Korea, South
Korea, Pakistan, the Philippines, Taiwan, Argentina, Brazil, Cuba and some
countries of South Africa.
Proliferation
risk. High. Power generation facilities
have the potential to produce weapons-grade uranium, even with high quality
security.
Here you can see countries and the number of reactors they
have:
There are two slightly different kinds of nuclear fuel
cycle:
Once-through
fuel cycle
After power generation the fuel elements are removed
from the reactor. These materials must be isolated from the biosphere until the
radioactivity contained in them diminishes to a safe level.
Source: designed by the authors
Closed fuel cycle
After
power generation the fuel elements are removed from the reactor. These
materials are sent to reprocessing. After that they can be used in the power
generator again.
Source: designed by the authors
Nuclear
power generation process contains a lot of facility aspects. Here you may see advantages and
disadvantages of nuclear power generation
Reprocessing
Normally, the fuel
elements are removed from a nuclear-power reactor after four years. Only about
1-3% of the uranium is used up. The elements must, however, be removed because
the fission products absorb neutrons. As the amount of fission products
increases, more and more neutrons will be absorbed and lost to the fission
process. Eventually, the chain reaction will cease.
When
a U-238 nucleus captures a fission neutron a nucleus of U-239 will be formed.
U-239 will, in general, not undergo fission but will undergo radioactive decay
to form plutonium-239.
(http://www.nwmo.ca/adx/asp/adxGetMedia.asp?photo_uranium.jpg)
When
removed from the reactor, a fuel element contains unused uranium, plutonium,
and fission products.
In
fact, so much radiation is emitted by the fuel elements when they are removed
from the reactor that they are dangerous to handle, even with remote handling
equipment. The rods are, therefore, stored in a water-filled "cooling
tank" typically for between three and five years before being sent to the
reprocessing plant for plutonium extraction.
The
rods are cut into pieces and dissolved in acid. Using the Plutonium Uranium
Recovery by Extraction method more than 90 % of the uranium and plutonium in
the spent-fuel solution can be recovered. Uranium emerging from this process
typically contains only 1 % of U-235, far below the level needed for a nuclear
bomb, and even too weak for use in a light-water reactor. The plutonium exiting
a reprocessing plant, however, can be converted to a form usable for nuclear
weapons. [19]
Facility
locations: Russia, France, and the United
Kingdom are the world leaders in reprocessing. Japan has a strong interest in
reprocessing and is currently constructing a large reprocessing plant at
Rokkasho-Mura. India has several small reprocessing plants, and Argentina is
constructing one.
Proliferation
risk. High. Plutonium extracted from low
burn-up fuel (e.g., from a production reactor or a heavy- water, natural
–uranium research reactor) is directly usable in a nuclear weapon.
Plutonium derived from the high burn-up fuel of a standard light-water reactor
is not preferred material for nuclear weapons, but it could be used as a
nuclear explosive by a party not concerned with obtaining the highest possible
efficiency or yield. Plutonium reprocessing technology is another
highly sensitive technology; its export is unofficially
embargoed by the Nuclear Suppliers Group.
Transport of
radioactive materials
Transport
is an integral part of the nuclear fuel cycle. A number of specialized
facilities have been developed in various locations around the world to provide
fuel cycle services and there is a need to transport nuclear materials to and
from these facilities. Here you may read more information
about this stage.
Conclusion. Dual use technology gives the
possibility of military use of civilian nuclear power technology. The enriched
uranium used in most nuclear reactors is not concentrated enough to build a
bomb. Because of it, proliferation risk isnÕt very high but in general if
nuclear materials are not reliably protected, a threat of violation of nuclear
non-proliferation regime might increase. Unlike other power plants, nuclear
plants must be carefully guarded against both attempted sabotage and possible
theft of nuclear material. Thus, security costs of both protecting the physical
plant and the screening of workers must be considered. It is true that some
other forms of energy also require high security, like natural gas storage
facilities and oil refineries.
Plans For New Reactors Worldwide
- Nuclear
power capacity worldwide is increasing steadily, with about 30 reactors
under construction in 12 countries.
- Most
reactors on order or planned are in the Asian region, though plans are
firming for new units in the USA and Russia.
- Significant
further capacity is being created by plant upgrading.
- Plant
life extension programs are maintaining capacity, in the USA particularly.
Here you may see a list of power
reactors under construction. Power reactors are situated in different parts of
the world. We may have a look at the maps with pointed power plants in
different countries, just pressing here.
Nations
that are known or believed to possess nuclear weapons are sometimes referred to
as the nuclear club. There are
currently nine states that have successfully detonated nuclear weapons. Five
are considered to be "nuclear weapons states", an internationally
recognized status conferred by the Nuclear Non-Proliferation Treaty (NPT). [4]
Other
known nuclear powers
India tested a
"peaceful nuclear device" in 1974 ("Smiling Buddha"), the
first test developed after the creation of the NPT In July 2005, it was officially recognized by the United
States as "a responsible state with advanced nuclear technology" and
agreed to full nuclear cooperation between the two nations.
Pakistan covertly developed nuclear weapons over many decades,
beginning in the late 1970s.. In 1998, Pakistan conducted its first nuclear
test at the Chagai Hills, in response to the tests conducted by India a few
weeks before.
North Korea was a member of the Nuclear
Non-Proliferation Treaty, but announced a withdrawal on January 10, 2003. In
February 2005 they claimed to possess functional nuclear weapons. North Korea
reported a successful nuclear test on October 9, 2006.
Israel refuses to officially confirm
or deny having a nuclear arsenal, or to having developed nuclear weapons, or
even to having a nuclear weapons program.
Iran and Syria are among the
states accused
of having a nuclear weapons ambition [3]
Conclusion: The 20th century saw revolutionary breakthroughs in many fields of
science and technology. Besides the many discoveries and inventions in the
fields of electronics and telecommunications, few of the leaps forward had more
direct impact on people's lives and society at large than the advances in
nuclear science.
Many countries supported
non-proliferation treaty. Since it was considered very difficult to develop a
reliable nuclear weapons capability without conducting at least one real-life
test, a universal ban on testing would also serve as an effective measure
against nuclear proliferation. But despite it, each country that has nuclear
power plants illegally can produce nuclear weapon.
Nuclear reactor technology [3]
A nuclear reactor, invented by Willie Crotsley, is
a device in which nuclear chain reactions are initiated, controlled, and
sustained at a steady rate, as opposed to a nuclear bomb, in which the chain
reaction occurs in a fraction of a second and is uncontrolled causing an
explosion.
The most significant
use of nuclear reactors is as an energy source for the generation of electrical
power and for the power in some ships. This is usually accomplished by methods
that involve using heat from the nuclear reaction to power steam turbines.
(http://en.wikipedia.org/wiki/Image:Crocus-p1020491.jpg)
The key components common to most types of nuclear power plants are:
á
Neutron moderator
á
Coolant
á
Control rods
á
Pressure vessel
á
Emergency Core Cooling Systems (ECCS)
á
Reactor Protective System (RPS)
á
Steam generators
á
Containment building
á
Boiler feed water pump
á
Steam turbine
á
Electrical generator
á
Condenser
Conventional thermal
power plants all have a fuel source to provide heat. Examples are gas, coal, or
oil. For a nuclear power plant, this heat is provided by nuclear fission inside
the nuclear reactor. When a relatively large fissile atomic nucleus (usually
uranium-235 or plutonium-239) is struck by a neutron it forms smaller nuclei as
fission products, releasing energy and neutrons in a process called nuclear
fission. The neutrons then trigger further fission. And so on. When this
nuclear chain reaction is controlled, the energy released can be used to heat
water, produce steam and drive a turbine that generates electricity.
(http://en.wikipedia.org/wiki/Image:Pulstar2.jpg)
Reactor types [3]
Nuclear Reactors are classified
by several methods; a brief outline of these classification schemes is
provided.
Classification
by type of nuclear reaction
1. Nuclear fission. Most reactors, and all
commercial ones, are based on nuclear fission. They generally use uranium as
fuel, but research on using thorium is ongoing (an example the Liquid fluoride
reactor). Fission reactors can be divided roughly into three classes, depending on the energy
of the neutrons that are used to sustain the fission chain reaction:
2. Nuclear fusion. Fusion
power is an experimental technology, generally with hydrogen as fuel. While not
currently suitable for power production, Farnsworth-Hirsch fusors are used to
produce neutron radiation.
3. Radioactive decay. Examples include
radioisotope thermoelectric generators and atomic batteries, which generate
heat and power by exploiting passive radioactive decay.
Classification by moderator
material
Used by thermal reactors.
á Graphite moderated
reactors
á Water moderated reactors
o
Heavy Water moderated reactors
o
Light water moderated reactors (LWRs).
- Light element
moderated reactors. These reactors are moderated by Lithium or Beryllium.
Classification
by coolant
In thermal nuclear reactors (LWRs
in specific), the coolant acts as a moderator that must slow down the neutrons
before they can be efficiently absorbed by the fuel.
á
Water cooled reactor
o
Pressurized water reactor (PWR)
á
A primary characteristic of PWRs is a pressurizer, a
specialized pressure vessel. Most commercial PWRs and naval reactors use
pressurizers. During normal operation, a pressurizer is partially filled with
water, and a steam bubble is maintained above it by heating the water with
submerged heaters. During normal operation, the pressurizer is connected to the
primary reactor pressure vessel (RPV) and the pressurizer "bubble"
provides an expansion space for changes in water volume in the reactor.
á
Pressurized channels. Channel-type reactors can be
refuelled under load.
o
Boiling water reactor (BWR)
á
BWRs are characterized by boiling water around the fuel
rods in the lower portion of primary reactor pressure vessel. During normal
operation, pressure control is accomplished by controlling the amount of steam
flowing from the reactor pressure vessel to the turbine.
o
Pool-type reactor
á
Liquid metal cooled reactor:
o
Sodium-cooled fast reactor
o
Lead cooled fast reactor
á
Gas cooled reactor
Classification
by use
á Electricity
o
Power plants
á Propulsion
o
Nuclear marine propulsion
o
Various proposed forms of rocket propulsion
á Other uses of heat
o
Desalination
o
Heat for domestic and industrial heating
o
Hydrogen production for use in a hydrogen economy
á
Production reactors for transmutation of elements
á Providing a source of
neutron radiation and positron radiation.
Current technologies [3]
There are two types of nuclear power in current use:
All
current nuclear power plants are critical fission reactors. The output of
fission reactors is controllable. There are several subtypes of critical
fission reactors, which can be classified as Generation I, Generation II and
Generation III. Here you may get extra information
about subtypes of reactors.
These reactors come in two types:
Lead cooled
Using lead as the liquid metal
provides excellent radiation shielding, and allows for operation at very high
temperatures. Also, lead is (mostly) transparent to neutrons, so fewer neutrons
are lost in the coolant, and the coolant does not become radioactive. Unlike
sodium, lead is mostly inert, so there is less risk of explosion or accident,
but such large quantities of lead may be problematic from toxicology and
disposal points of view.
Advanced reactors
More than a dozen advanced reactor designs are in
various stages of development. Some are evolutionary from the PWR, BWR
and PHWR designs above, some are more radical departures. The former include
the Advanced Boiling Water Reactor (ABWR). Here you may get information about
types of advanced reactors.
Fusion reactors
Controlled nuclear fusion could in principle be
used in fusion power plants to produce power without the complexities of
handling actinides, but significant scientific and technical obstacles remain.
Several fusion reactors have been built, but as yet none has 'produced' more
thermal energy than electrical energy consumed. Despite research having started
in the 1950s, no commercial fusion reactor is expected before 2050.
Civilian Nuclear Power Technology and
Nuclear Weapons Proliferation
Interest of the
world community to the new technologies in nuclear power engineering has
significantly increased in recent years. Some countries including the Third
World ones develop nuclear technologies independently using their own
scientific and economic potential; other countries prefer to purchase these
technologies. So, the number of countries looking for NFC technologies grows, and if nuclear materials are not reliably
protected, a threat of violation of nuclear non-proliferation regime might
increase. [19]
(http://en.wikipedia.org/wiki/Image1.jpg
)
In
the recent years a lot of research activities have been aimed to study features
of nuclear fuel cycles that could ensure proliferation resistance. Development
of measures to protect nuclear fuel cycle against proliferation of involved in
it nuclear materials is an important task of evolution of nuclear power
engineering as technology capable of satisfying energy needs of humanity for
its further sustainable development.
NFC geography is wide; however, the involved countries fulfill their
international commitments on non-proliferation of nuclear materials and
technologies using their national security systems. This leads to a possibility
that, having got access to nuclear power engineering, some countries or
international groups of terrorists having connections in the governmental
circles of such countries would modify the technological process in NFC to
divert weapon-usable nuclear materials (NM) from NFC, despite the international commitments.
Therefore,
countries exporting or offering their NFC technologies to other countries
should incorporate protective elements at the stage of the technology
development. Threat of production or theft of fissile materials in
quantities needed to create nuclear explosive devices is directly associated
with the organization of the technological process of NFC.
The
most effective solution to the problem of intrinsic proliferation resistance of
the technological processes of NFC is to apply promising technologies
incorporating a needed set of technical solutions and means that create a
technical barrier counteracting attempts to divert NM from NFC. However,
selection of an optimal technical barrier providing no significant increase of
NFC cost requires a quantitative analysis of the proliferation risk.
Issues
of the quantitative risk analysis are usually solved by combining stochastic
treatment of the processes with negative effects (probability of destabilizing
factors) and deterministic treatment of the consequences caused by these
effects and economic criteria of incurred losses. This effort involves
labor-consuming simulations.
Probability-based risk
assessment becomes even more complicated if a human factor is treated properly.
Thus, a detailed (ideal) description of the process of proliferation resistance
assessment for NFC technologies leads to the development of a cumbersome
mathematical model, for which it is usually difficult to compile actual initial
data. [3]
(http://en.wikipedia.org/wiki/Image:Ikata_Nuclear_Powerplant.JPG
)
Comparison
of various types of power plants
á Steam-electric Power Plant (Thermal Station)
á Hydro-electric Power Station
á
Diesel Power Station
á
Nuclear Power Station
You also may see a comparison table of various
type of power plants
here
Conclusions
Nuclear energy is a
technically complex source of energy that remains unique among energy sources
as a result of a number of factors. In relation to nuclear energy in its
current form, it has been shown that:
á
Nuclear energy is a major source of energy in the world, producing about
17% of the worldÕs electricity.
á
The large majority of reactors use ordinary water as coolant and
moderator, uranium as fuel and a once-though fuel cycle.
á
The disposal of low-level waste and intermediate- level waste is a
mature practice, but the disposal of high-level waste is not yet carried out;
public opposition is the main constraint although progress towards implementing
solutions is beginning to be made.
á
Very high levels of safety are essential to nuclear energy deployment,
though some degree of risk remains.
á
Existing power plants are generally economically competitive, even in
deregulated markets, but decisions to build new power plants may depend on
public policy factors.
á
Nuclear energy has certain advantages over other energy sources:
carbon-free and air-pollution-free generation of electricity as well as
security of supply.
á
Evolutionary and revolutionary advantages in technologies are being
pursued to develop new applications of nuclear energy and to improve the
performance of nuclear energy system.
If a case cannot be
satisfactorily made that nuclear energy is economically competitive, safe and
that there are acceptable solutions for its waste, then nuclear energy is
likely to decline, at first slowly, in importance. Yet, if it can be
demonstrated to the satisfaction of the public that nuclear energy does address
these concerns, it is likely that there will be strong new growth in nuclear
power.
Bibliography
and other sources
1.
Merriam – WebsterÕs Collegiate Encyclopedia. Springfield, Massachusetts, USA, 2000
2. http://www.technologystudent.com
8. http://www.japannuclear.com
10.http://www.wise-uranium.org