Nuclear Energy: Uranium Fission


Thousands of years ago human beings learned to make fire. By collecting
and burning wood they were able to warm themselves, cook food, and manufacture
primitive tools. Later, the Egyptians discovered the principal of the sail.
Even more recent was the invention of the water wheel. All of these activities
utilize various forms of energy-biological, chemical, solar, and hydraulic.
Energy, the ability to do work, is essential for meeting basic human
needs, extending the life expectancy, and providing a rising living standard.
This is where the need for nuclear power comes in. Uranium fission is
about a million times more efficient than the common practice of burning coal or
oil. For comparison, coal combustion produces about 20-30 MJ/kg of heat energy
while uranium, in a fast breeder reactor, produces more than 24,000,000 MJ/kg
(Energy 27). Those numbers alone are astounding.
Uranium is also abundant, thanks to recent discoveries of large reserves.
At present, uranium is only being mined and separated from ore. However, a
huge untapped source is our oceans. Sea water contains 3.3x10^(-9) (3.3 parts
per billion) of uranium, so the 1.4x10^18 tons of sea water contains 4.6x10^9
tons of uranium. All the world\'s electricity usage, 650GWe could therefore be
supplied by the uranium in sea water for 7 million years(Energy 25). This is a
only a theoretical number because it is not possible to get all of the uranium
out of our vast oceans. Also, it does not include the fact that in that many
years, half of the uranium will no longer exist due to radioactive decay. So,
at worst, we would get about 2 million years of power from it. Thorium is
another element than can be used in nuclear reactors. Thorium is approximately
four times more abundant than uranium. It is obvious that we are in no danger
of exhausting these sources of energy. We need to exploit these resources an d
use them to our advantage. God has given us the knowledge to use uranium for
power, so why shouldn\'t use it? There are many benefits to using nuclear
generated power over our other common sources.
A big advantage of nuclear power plants is that they do not burn
anything, they are non-polluting, and they are kind to the environment. Unlike
coal-, gas-, and oil-fired power plants, nuclear power plants do not emit carbon
dioxide and other harmful greenhouse gases into the atmosphere.
This is not to say that no waste is produced in a nuclear reaction. An
average size nuclear reactor produces 1000 MWe and leaves behind about 25 tons
of spent fuel. This product is highly radioactive and gives off a great deal of
heat. However, it can be reprocessed so that 97% can be recycled. The
remaining 3%, about 700kg, is high-level radioactive waste that needs to be
isolated from the environment for many years (Gale 22). This small quantity
makes the task readily manageable. Even if the fuel is not reprocessed, the
yearly amount of 25 tons is modest compared with the quantities of waste from
similar sized coal-fired power plants. And, the spent fuel could be stored and
then reprocessed many years later if the need arose.
For comparison, a 1000 MWe coal-fired power station produces about seven
million tons of carbon dioxide each year, plus perhaps 200,000 tons of sulfur
dioxide which remains a major source of atmospheric pollution. There are
approximately 200,000 tons of other wastes produced including toxic metals,
arsenic, cadmium, mercury, organic carcinogens (which causes cancer and genetic
mutations) and, surprisingly to most people, naturally occurring radioactive
substances (Jones 13).
The nuclear industry is unique in that it is the only energy producing
industry that has taken full responsibility for the disposal of all its waste
and pays the full cost of doing so.
By the laws of supply and demand, the large supply of uranium keeps the
price down, unlike the situation with crude oil. From the outset the basic
attraction of nuclear energy has been its low fuel costs compared with coal, oil,
and gas fired plants. Uranium, however, has to be processed, enriched, and
fabricated into fuel elements. About one third of the fuel cost is due to
enrichment. Allowances must be then be made for the management of radioactive
spent fuel and the ultimate disposal of this or the wastes arising from it.
Nonetheless, with these costs included, the total fuel costs of a nuclear power
plant are typically about one third of those of a coal-fired plant and about one
fifth of those of a gas combined cycle plant (Economics 35).
Uranium has