Environmental Engineering Reference
In-Depth Information
6
Nuclear power is not based on mechanical energy (as is hydropower) or chemical
energy (as is the burning of fossil fuels). Nuclear energy is created by the splitting
of the nuclei of uranium atoms. This splitting releases a considerable amount of
kinetic energy in radioactive fragments such as strontium (Sr) and xenon (Xe).
This process is called “nuclear fission” and can be induced by bombarding uranium
atoms with suitable projectiles such as neutrons. Nuclear fission is followed by
neutron or proton emission and by radiation, such as X-rays. The final fragments,
the nuclear waste, are highly radioactive, and thus are one of the serious problems
resulting from the use of this type of energy.
In the fission of a uranium atom by a neutron, 2.5 other neutrons are produced,
on the average all of which can, in turn, produce other fissions, creating a chain re-
action that leads to the fission of a huge amount of other atoms. If this process hap-
pens quickly, it produces a nuclear explosion, which is basically a large number of
uranium atoms undergoing fission in a short period. If the process is slowed down,
then large quantities of heat are produced as the kinetic energy of the fragments
dissipates. In a nuclear reactor this heat is removed and used to boil water and the
vapor generated is used to produce electricity, as it is done in thermal power gen-
eration stations that burn fuel wood, coal, or gas.
Table 6.1 Comparison of the power generated from different energy sources
