Nuclear
Energy, which is created inside a nuclear reactor, is a form of power which has
become an essential part of today's society.
Does this source of energy benefit the lives of human beings,
particularly Canadians and the rest of the world? Do the advantages outweigh
the disadvantages, or does this form of energy create a hazard to the
Earth? Are human beings being subjected
to harmful radiants? Are the hazards of
nuclear energy over-exagerated? Canada,
as the likes of many other countries around the world, has come to the point of
deciding to what (if any ) degree it will or it should use Nuclear energy.
SCIENCE and TECHNOLOGY
A
nuclear reactor is a device which produces heat. In the reactor, heavy water (water with a
mass number greater than one) also known as
'deuterium oxide', is heated up and the steam produced is used to spin
large turbines, which in turn drive generators that produce electricity.
Synopsis of reaction:
There
is more than one type of nuclear reactor in use throughout the world, though
clearly they all work on the same principle, by creating 'a nuclear
reaction'. The process which makes a
nuclear reaction happen is known as 'nuclear fission'. Using the large nucleus of a uranium atom as
the basis for this reaction, a neutron collides with the uranium nucleus to
begin the process. The large nucleus
then splits into two smaller nuclei and these are known as Fission
products. From this reaction energy is released
in the form of heat, and several neutrons are also emitted as by-products. Finally, the heavy uranium nucleus emits rays
during this transformation. These rays
are called alpha, beta and gamma rays. These rays are a form a radiation which
is known as 'radioactivity'.
This fission reaction can be done over and
over again to produce a constant source of energy. There is a chain reaction that occurs, the
two or three neutrons that are emitted as a by-product of the reaction are then
sent flying off into other uranium nuclei, and the process is started all over
again.
Since
the sub-atomic particles are moving at very fast rates, the speed of the
colliding neutrons must be slowed down, and Canadian reactors use heavy water
to do this. This is why the Canadian
reactors are known as CANDU reactors, CANada Deuterium Uranium. There are more than twenty of these 'CANDU'
reactors operating in Canada today. Of
course, as mentioned not all countries have the same kind of nuclear reactor. For instance, instead of using heavy water to
cool the reaction down, reactors in Great Britain use gas-cooled reactors.
The
nuclear process is one which requires Uranium, this is an element found in
great abundance in the Earth's crust. It
is mined and extracted from both open pit and underground mines. Canada is has large deposits of this mineral
in several regions. One of these regions
is in northern Saskatchewan's Athabasca basin where open pit mines yield 60% of
Canada's uranium supply; and the other region is in Ontario's Elliot Lake
district, where underground mining brings the other 40% of Canada's uranium
supply.
The Fuel Cycle:
The
uranium which is mined from the Earth's crust is extracted in raw ore state.
There is a process which prepares the element for use in the actual
reactor. This is known as the CANDU fuel
cycle. After the ore is taken from the
mines in Canada it is crushed into tiny fragments and shipped for milling. The uranium is then ground into a fine powder
and chemically treated to produce a uranium concentrate. This concentrated element is refined and
processed to from hard ceramic pellets.
These
pellets look like one-inch stacks of dimes, and are the fuel for the basic
nuclear reaction. The pellets are then
placed in rods and packed in a fuel bundle about 10cm in diameter and 50cm
long, weighing about 25Kg.
The
actual reaction is only a small part of the nuclear process, which can be split
into several sections. There are two
very distinct parts to a nuclear power station, the nuclear reactor and the
turbine that produces electricity. In
the reactor (1), heavy water is heated up by the energy released when uranium
atoms are split. The reactor has the
same use as a furnace where coal, gas, or oil is heated up to make steam. The heavy water circulates through a heat
exchanger (2), Where it boils ordinary water to produce steam (3). The heavy water is then circulated back to
the reactor (4). The steam produced in
the heat exchanger passes through a turbine (5), causing it to turn. The turbine (5) is connected to a generator
which produces electricity to provide energy to households and industries. The steam leaving the turbine is turned back
into ordinary water when it is cooled in a condenser (6). The ordinary water (7) is then recycled back
through the heat exchanger and the cycle begins again.
Safety:
"All
man-made facilities should be designed to be safe, whether they be football
stadia, chemical factories, houses or nuclear power generating stations. What is 'safe' is normally defined by
government at some level or other, or by professional bodies so authorized by
government... emergency measured have to be initiated to cope with unusual
circumstances. (situations that should not have happened.)
The
safety of nuclear reactors is a major concern to everyone. CANDU reactors have numerous shut-down
procedures and precautions that can be utilized in an emergency situation. The safety philosophy used in the CANDU
nuclear power plants is to limit the chances of an accident occurring and to
limit the effects of an accident should one occur. This is called the 'defense in depth'
approach. There are five main defense in
depth areas:
1. High quality station equipment
2. Nuclear plant operator training
3. Fault detection and correction
4. Independent safety systems
5. Containment systems
All
equipment used in or around the CANDU reactors are tested to make sure that
they are of the highest quality. All
critical pieces are duplicated so that if a sensing device breaks down, a
second identical device can take over.
This makes sure that one component doesn't jeopardize the operation of
the station.
The
nuclear reactor operators are highly trained, skilled individuals. they are carefully selected and spend about
eight years in training. They have to
pass a series of exams before they can become licensed operators. The Atomic Energy Control Board (AECB) set
these exams and control who passes and who does not.
Each
nuclear power plant has a geiger counter which can detect event the most minor
earthquake and take precautions to protect the reactor.
Canadian
reactors are equipped with safety systems with the sole purpose of shutting
down the reactor in the event of any major equipment malfunction. In the CANDU reactors these systems include:
- the
high speed insertion of shut-off rods into the reactor to immediately stop the
nuclear reaction.
- the
injection of products into the reactor to further stop the nuclear reaction.
- the
discharging of the moderator, needed to sustain the nuclear reaction.
Canadian
nuclear reactors are also equipped with an emergency cooling system which would
continue to remove heat from the reactor should the primary cooling system
fail.
There
is also a containment system that surrounds the reactor so that the radioactive
pollutant does not escape into the surrounding environment. The walls of the containment building are
about 1.8m thick. There is also a vacuum
that is hooked up to the reactors, which helps assume some of the containment
function.
Nuclear Waste:
After
the uranium is mined, processed and then reacted, there is radioactive waste
that must be dealt with. The control and
risk involved in the managing of these wastes is a concern that is taken care
of with stringent policies. Two types of
wastes are generated by a nuclear reactor one being low-level waste, which
would be items such as buckets, clothing, gloves, mops and other items that as
come into contact with radioactive material.
The other type of radioactive waste which makes up 99% of all
radioactive waste is fuel that has been in a reactor for more than 1.5 years,
and is called high-level waste.
The
low-level waste is stored in concrete buildings either above or below the
ground. The high-level waste are removed
from the reactors with special machines and are then moved to storage bays that
look like giant swimming pools, they are located within the power station and
are used to shield the radiation from the environment. After 5 years of storage in these pools, it
is possible to move the waste to a dry storage facilities.
Although
most of the radioactive waste is stored on-site, there are some areas of Canada
that have disposal vaults created to keep some of the high-level waste safe
from people and the environment. They
are like underground mines, here experiments are conducted, and the waste is
kept 1000 meters below the surface of the Earth compacted in clay. The vault is then tested for leaks, and
radiation, and then backfilled. The
surface would then be returned to normal use.
A single vault could hold all the radioactive waste from all Canadian
reactors in a 100 year period. These
vaults can only be placed in areas where there are no earthquakes, the Canadian
Shield fits this description.
THE SOLUTIONS
There
are three ways that the Nuclear issue can be solved. The first would be to have nuclear power
stations in several areas in Canada, with numerous nuclear reactors in some
provinces. The second solution would be
to stop the construction of all nuclear power stations, and to shut down the
existing reactors. The third and final
solution would be to have nuclear power in Canada with very strict laws and
regulations on where they can be placed, and on how many reactors can be built
in a certain area and during a certain time span.
THE OUTCOMES
If
nuclear power plants were the primary power source of Canada and it's
population, there would be many advantages and some disadvantages. First the advantages. Nuclear power is a very efficient and cheap
operating method of producing energy in comparison to oil, and coal energy
production.
The
Efficiency of nuclear energy
500 grams |
coal | = 1.5 KW hours |
500 grams |
oil | = 2.0 KW hours |
500 grams | uranium | =82,000 KW hours |
The
electricity needs of Canada increase every year, we must use a source of energy
that will be able to power our country for many years to come. With coal and oil already being mined for
many years, they cannot last for very long.
Uranium, however, has been mined since 1962, and is in great abundance,
with only small amounts being used for Canada, and 85% exported to other
countries, for use in their nuclear facilities.
Two
nuclear power stations produce just as much electricity as the James Bay
hydro-electric development in in Quebec. Using uranium saves money and energy, less
coal has to be imported from the U.S.
Nuclear
energy is better for the environment than the coal and oil-burning power
plants. There is no smoke, there is no
combustion products that escape into the atmosphere. Nuclear reactors produce steam instead of
carbon dioxide, nitrogen dioxide, and fly ash.
This helps avoid the 'greenhouse effect' which threatens to make global
temperatures rise, causing flooding of many areas in Canada, and droughts in
other areas of the country. The process
used in creating nuclear energy does not emit sulphur dioxide or nitrogen
oxides, both created in the burning of coal.
These chemicals are the main reason for 'acid rain' and for the killing
of thousands of lakes, bodies of water and forests both in Canada and
worldwide. With nuclear energy, there is
no need for the flooding of large areas, no need to disrupt millions of
hectares of land and areas, no need to disrupt millions of hectares of land and
communities to generate power, as is necessary with hydro-electric power.
There
is no need for long transmission lines when using the nuclear reactors, they
can be built relatively close to the population they will be serving. For instance, the Pickering power station is
32km from Toronto, on the shore of Lake Ontario.
There
would be little waste involved with nuclear energy, compared to the amount
produced by burning coal. The waste from
nuclear energy is contained in a small area, below ground in a vault (as
explained earlier on), the waste from coal burning is released all over the
atmosphere and left to disperse in the sky and fall to the ground.
Nuclear
energy is the answer for countries which do not have natural resources on their
land. If there are no fossil fuels
available then the best option would be to build a reactor to fill the power
needs of the population.
The
nuclear industry will create thousands of jobs for Canadians. The mining, the production of reactor fuel,
the manufacture of equipment, and the generation of electricity all employ
thousands of people.
Radiation
from the nuclear power stations is extremely minimal. Compared to watching television, getting
x-rayed at the doctors office, flying in a plane, or using a microwave, the
amount of radiation people get from living near a reactor is very minimal.
5
millirem: The amount of natural
radiation that a person gets on the outside perimeter of a nuclear generating
station in one year.
220
millirem: The normal background
radiation from natural sources each year at sea level. This is the average minimum dose received by
most people on Earth and the probability of cancer is 1 in a population of
100,000.
10,000
millirem: If given instantaneously, it
would not cause obvious illness; it might cause cancer many years later in 1 in
1,000 people exposed to this dose.
If
all construction of nuclear power stations were ceased, and Canada shut down
all it's nuclear reactors in operation at this moment, there would be benefits
and disadvantages in many aspects of this solution. To start, the risk of having any sort of
radioactive spill, emission, accident, or any other form of radioactive leak is
nullified right off the bat. There will
be no more danger to the population of Canada to do with nuclear waste
transport, or storage. There will never
be another mishap to do with mining, milling, or refining uranium into nuclear
reactor fuel pellets in Canada.
With
the absence of nuclear power people will not be exposed to the nuclear
radiation that is associated with the operation of the power station. There will be no genetic defects, cancer,
injury or death caused by radiation any longer.
The
hazardous working conditions that the people who are employed by the nuclear
industry will be no more, people will not be needlessly exposed to harmful
radioactivity.
If a
full-fledged accident ever occurred with a nuclear reactor, thousands would die
immediately, their systems would not be able to function with such large
amounts of radioactive material within itself.
Other residents of close proximity to the accident that do not die are
very susceptible to cancer, this would eventually kill them as well. There are many genetic effects that could
affect future generations of humanity.
Large land areas would become contaminated by the poisons, prohibiting
further habitation or cultivation uses.
If
nuclear power were banished in Canada, electricity would not be as attainable
as it currently is. There would be
blackouts during certain periods of the night, and power shortages would become
unavoidable. This is because the fossil
fuel burning plants simply do not produce as much energy as does a nuclear
power station. One way to heal this problem would be to
build more fossil fuel burning plants.
Drawbacks to this idea include, having more pollution in the atmosphere,
speeding up the effects and symptoms of the greenhouse effect, the acid rain
problem and the ozone layer depletion.
Another drawback of having more fossil fuel plants would be that it
would be imperative for Canada to purchase more fuel for the power plants to
burn annually.
As a
result of not having nuclear energy, Canada would be able to export 100% of
it's uranium ore. Bringing in money that
would be needed to combat the power shortages and prices of new fossil fuel
burning stations. Canada would also have
to look towards new directions in solving the energy crisis, the country could
begin to use wind power, solar power, and thermal energy which is found in the
core of the Earth, and the energy attained from burning garbage.
If
nuclear power stations were allowed in Canada but only under the condition that
they were placed in very secluded parts of Canada, there would be advantages
and disadvantages.
The
population of Canada would be exposed to less radiation than they currently are
being subjected to. This would result
from the sheer distance of the nuclear reactor to the nearest populated
city. Not only would the radiation
hazard be less of a problem, but the hazard of having a radioactive spill,
accident, or a nuclear meltdown affecting thousands of people would be decreased
dramatically. The scenario of having
many deaths and birth defects would be one that could never happen.
The
reactors would be placed in regions of the Northwest Territories, Yukon
Territories, and northern Quebec. This
would make use of land that is not currently in use, settling the north,
creating jobs for people that would not have the opportunity to ] a job
otherwise.
The
disadvantages of this situation begin with the fact that the shear distance of
transferring the electricity to the different cities in need of energy would be
done primarily with power lines, which are often inefficient and costly.
Much of the land in the Northwest and Yukon
Territories is inhabited by Native peoples, their culture might become
disrupted with the intrusion of a nuclear power plant in close proximity to
their burial grounds, villages or hunting areas.
Since
a reactor takes hundreds of people to maintain it, the families of the workers,
technicians, and operators involved in the power station would eventually settle
in the region. This would create a small
community and possibly a city, and could give the economy of the area a little
'boost'.
INTEREST GROUPS
There
are several interest groups which are associated with nuclear energy. They include, homeowners close to a nuclear
power station (which also include the employees of nuclear industries), all
Canadian homeowners, environmental groups such as Greenpeace (who are
anti-nuclear), and pro-nuclear groups such as the atomic energy control board
(AECB).
The
first group, homeowners who are close to a nuclear power station, have some
mixed views about nuclear power. These
homeowners feel, that by allowing uninhibited use of nuclear power stations in
Canada, that they can live everyday normal and comfortable lives. There are small risks of food and drinking
water contamination but these are risks which they feel they are able to live
with.
Even
with the knowledge that they are only receiving 5 millirems of radiation every
year, and that this amount is the same amount of radiation as a person on a
round trip from Toronto to Vancouver would be exposed to, they are still
reluctant to consider that their living environment is safe enough.
This
interest group probably has many associates who work directly, or who have
family working in the nuclear power industry.
The associates of this interest group probably
would be happy to have a direct or indirect link to a secure, high-paying job
with a crown corporation.
What
if nuclear power stations were banned and ceased producing energy? In this case the local homeowners would be
more displeased than pleased. Yes, it is
true that the threat of radiation emissions contaminating the food and drinking
water would cease to exist.
What
about the economic viewpoint? The families
of the
workers (who worked in the nuclear power
stations) and the community (surrounding the nuke power station) would feel an
economic slow-down due to abstinence of demand (no cash flow, no business, no
demand). A loss of a nuclear power
station would very much annoy this interest group as they would suffer
economically.
We
know come to the issue of our daily habits.
These people, like all other Canadians, are used to the availability of
electricity at the flick of a switch.
They would have the annoyance of blackouts and power shortages,
something that materialistic Canadians would not be ready to accept.
How
about limiting these nuclear power stations and moving them areas in Canada
which are sparsely populated? When the
nuclear plant has moved, it would mean one less risk factor in the
community. There would be no risk of
nuclear waste contaminents found in the food and\or water supply.
If
nuclear power plant is moved, the workers (and their respective families) would
have to move to relocate their jobs.
However, a move from a dense area (such as Pickering) to a sparsely
populated area in the northern areas of Canada would create a drastic change in
a family's living environment. Are there
enough Canadians who are willing to work in jobs away from the convenience of
large industrialized city?
The
second group, the people employed by the nuclear industry would probably be
happy by having nuclear energy as the primary energy source of Canada. These people's jobs would remain, which means
a constant and secure source of income.
The
lives of these employees will not change, they work in the industry knowing all
the benefits of nuclear energy used in powering a large share of the country's
energy.
If
nuclear power stations would cease to exist and produce energy, many of
Canada's jobs would be on the line.
Actually, about 100,000 people would be put out of work. All these people are employed either directly
or indirectly through the nuclear industry.
This represents a large part of this country's workforce.
This
interest group would protest the extinction of nuclear energy the most. These workers would have no more jobs. They have to receive re-training,
re-establish themselves in a the field of the new energy source (if there was
one), and they would have to move to their jobs.
The
third group, Canadian homeowners, would (by the majority, but not all) want to
have nuclear power as a main source of energy for Canada. All Canadians are used to having energy available
by using a plug or switch. Every day of
our lives, we can turn on light switches, we can turn on our televisions and
VCR's, and we can turn on our household appliances. Canadians enjoy the energy sources and uses
as they are today.
Most people watch t.v. and the nuclear energy
commercials which show 'their energy' to be harmless and efficient. In today's society, Canadians are more
concerned with the air they breath, and the sun which tans their skin, than the
contaminants which lie 1km below the ground.
For most Canadians, Nuclear energy is the cheapest and cleanest way to
produce energy.
The
only time Canadians do complain about our energy situation, is during the
blackouts of electricity. It is vital
for Canadians to have Nuclear power because it is constant source of energy
which causes less of burden (in their minds) than other energy sources.
Canada
could one day decide to stop using nuclear power stations as a source of
energy. Many Canadians would be unhappy
about such a decision. Canadians would
have to accept alternate energy sources, such as: Windmills in their gardens or Solar panels on
their roofs. These sources of energy
work only during specific conditions and\or times of the day. Another source of energy could come from less
efficient coal and oil-burning energy stations.
For most Canadians, living with uncertain energy sources would be
costly, both in the economical and the cultural sense.
Canadian
homeowners would probably be most happy with the third solution (discussed
earlier). Nobody wants to have a nuclear
power station in their backyards or within vicinity of their homes. Any nuclear meltdown or accident of any kind
would affects a lot less, if these nuke power plants were far away in northern
Canada.
Most
citizens are also aware of the radiation which emitted from these power
stations, and would please the citizens to know that such a 'station' is
hundreds of km's away from their homes.
A
move of nuclear power stations to the northern regions of Canada would cause an
annoyance for the workers in the nuclear industry. Even though their jobs would be kept, they
would have to relocate to these isolated regions of Canada. The fact that a nuke plant is relocating is
indifferent to them because they still have work in the nuclear industry
environment.
These
workers would be happy that they did not lose their jobs and that are given a
chance to continue working in the nuclear industry even it would mean working
and living in a new environment. Many
families would have to be dislodged as they would have difficulties settling in
a new environment.(other spouse may have a job; kids in school; etc...).
In
Canada, there is one global interest group in particular, which is dedicated to
protecting the environment and it opposes the use of nuclear energy, this group
is known as Greenpeace.
Greenpeace
is a group that opposes nuclear energy, they believe that the radiation is a
problem for society. Greenpeace feels
that radiation from nuclear energy inflicts serious harm and damage to our
environment. This organization feels
that many people are being harmed by the radiation that is being emitted from
the plants. They value the protection of
the world's environment, and they are against anything that harms it. This is how Greenpeace voices their opinion:
"The
world around us is a world where human error meets sophisticated technology,
where people make a sequence of logical decisions for the right reasons only to
find that they have created chaos...
Homo Sapiens retain a natural skepticism towards nuclear matters, and it
is encouraging to note that 'radiophobia' is one of the fastest growing human
attitudes in all societies. This global
phenomenon is a sign that ordinary people instinctively understand that
radiation damages living cells and an indication that they are not prepared to
suffer consequences any longer."
A
Canada without nuclear energy, would very much satisfy Greenpeace. Greenpeace would be able to say that the
radiation no longer harms the environment, and that there is no longer a chance
to destroy human beings, animals and their habitat, as was case in the
Chernobyl accident in the U.S.S.R. in 1986.
Greenpeace
also opposes any form of pollution to the environment and therefore would not
relish the idea of having to build more fossil fuel or coal burning energy
plants. It looks like even this solution
is one that will not satisfy the environmentalists.
What
if we decided to produce nuclear energy in the northern regions of Canada? Greenpeace would oppose this. Greenpeace feels that their wildlife, and
forests are being exploited, and that the people that have rights to the land
are being bothered with the nuclear power plants being opened up near them.
What
about the nuclear power plants that are closed.
How long would these nuclear reactors have to stand before it could be
considered safe to demolish?
Greenpeace
is one group which would like to see Canadians resort to non-polluting methods
of producing energy. These sources
include: Solar, wind, and thermal power.
The
last interest group to be discussed, is what we would call a pro-nuclear
group. This group would consist of the
Atomic Energy board of Canada, Ontario Hydro, and many Canada's high-energy
consumers (ie: Steelmills, automakers,
etc...).
This
group would have no problem having nuclear energy as Canada's primary energy
source. These people feel that nuclear
power is a benefit to society and that it is a cheap, clean, efficient way of
producing energy. This group likes to have energy power in abundance, and they
cannot settle for having shortages of energy without the nuclear power
stations. They feel that there is no
problem with emissions, that the emissions are harmless in the small doses to
which we are exposed to.
This
group is against using fossil-fuel and\or coal burning plants. Pro-nuclear groups feel that nuclear energy
is the only way that the environment can stay 'green' without seriously
contaminating the land, the air and the water.
Pro-nuclear groups would be obviously very
disappointed if nuclear power stations would cease producing energy. Again, here their argument would be that the
other sources of energy would be much worse to the environment if the same
energy production capacity is expected.
If
nuclear power plants were only in the northern regions of Canada, this group
would object. New power plants would
have to be built, power lines would have to be erected. Losses in energy would be enormous to the
efficiency of the power lines. This
group feels that the radiation emissions from nuclear power stations are a
fraction of the damage which fossil fuel emissions will create from oil or coal
burning.
A Report on
Nuclear Energy
presented to: Mr. Sedgewick
class: Science in Society
Date: Friday, May 15
