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Nuclear Energy: Uranium Fission

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...