Environmental Engineering Reference
In-Depth Information
and India. The total installed capacity in the world is approximately the same as for
hydroelectric-generating units.
The percentage of the world's electricity produced by nuclear energy has been
declining in recent years. New grid connections peaked at 30 GW/yr in the
mid-1980s, and the last decade has witnessed a decline to 5 GW/yr or less. Efforts
are being made to extend the life of existing plants and to stimulate the building of
new ones so as to promote “a nuclear renaissance” and thereby sustain the share of
nuclear energy in a growing global electric power sector. This is what the Nuclear
Energy Agency of the Organization for Economic Cooperation and Development
(OECD) and the International Atomic Energy Agency feel is achievable prior to
2050.
The construction of most of the existing reactors began before 1975 and was com-
pleted by 1985. After the incidents at Three Mile Island, in the United States in
1978, and Chernobyl, currently in Ukrainian territory, in 1986, construction of new
reactors declined dramatically.
The reasons for this decline are complex and involve economic, environmental,
and political concerns. For one thing, economies of scale have driven up the size
of the present generation of nuclear reactors, most of which are in the gigawatt
range, requiring several billions of dollars in investments. Relatedly, the increases
in safety requirements and decommissioning costs also affect the economic feasib-
ility of nuclear power. As opposed to other technologies and against optimistic pre-
dictions, nuclear power has not been shown to follow a “learning curve” process
whereby costs decrease with economies of scale. Furthermore, there are political
concerns, mostly related to the danger of nuclear proliferation, since nuclear tech-
nology is basically a dual technology allowing diversion of enriched uranium or
plutonium for the manufacture of nuclear weapons. There are also problems related
to nuclear waste disposal.
Elements removed from a reactor after its use correspond to less than 1% of the
waste volume, but they contain 95% of the total radioactivity. Radioactive atoms
are unstable and emit particles or radiation (“decay”) until they are transformed in-
to stable atoms. This is a statistical process and it is characterized by a half-life,
