NUCLEAR ENERGY: ENVIRONMENTAL EFFECTS
Under normal circumstances, very little air pollution is produced from nuclear power plants. In the case of an accident, however, nuclear pollution can be far more deadly than air pollution resulting from the use of fossil fuels. The accidents at Three Mile Island and Chernobyl had a dramatic effect on the nuclear industry and on public's attitude toward nuclear energy. Despite the fact that no one died in the 1979 TMI accident, the nuclear industry has yet to recover from its negative effects; no new nuclear plants have been ordered by U.S. electric utilities since the accident. The public lost confidence in nuclear energy technology; we were told that such accidents could not occur. The accident at Chernobyl was a major ecological and human tragedy; it caused dozens of immediate deaths, and thousands of cancer-related deaths.
The principal objective of the peaceful use of nuclear energy is to produce heat, which is then converted to work and finally to electricity. But in the process of producing heat, radiation is also emitted. This is what we call radioactivity. While being transformed into stable elements, radioactive isotopes release alpha particles (nuclei of the helium atom), beta particles (electrons) and gamma rays. For example, radioactive uranium decays to the now familiar radon in the following sequence:
U-235
In order to assess the damage caused by radioactivity, two aspects must be evaluated:
- How much radiation is emitted?
- How much radiation is absorbed by human tissue (cells, organs, etc.)?
Emission of radiation is most conveniently quantified using the concept of half-life.
lrr3@psu.edu (last revised 7/11/95)