A nuclear power plant generates electricity
when the nuclei of radioactive atoms disintegrate and release energy into surrounding
water. This heated water is converted to steam which turns a turbine that generates
electricity.
The steps in the uranium fuel cycle include
uranium mining, milling to concentrate the ore, enrichment to increase the percent
of U-235, fabrication which converts it to powder, and use in the reactor.
The spent fuel is either reprocessed or undergo waste storage.
A rem, or roentgen equivalent
man, is a measure of the biological damage to tissue caused by certain
amounts of radiation. The effects of large doses are easily seen and quantified,
however, the effects of low doses are more difficult to quantify.
A nuclear chain reaction occurs when the
neutrons released from a splitting nucleus strike the nuclei of other atoms
causing those atoms to split. This results in more neutrons being released which
causes other atoms to split; thus causing a chain reaction.
Each of these issues makes it increasingly
difficult to justify new nuclear power plants. The cost of construction, decommissioning,
and clean-up are greater than initially anticipated thereby making the cost
of the electricity generation much greater. In addition, the health hazards
of working with U-235, its transportation, and waste storage far outweigh any
benefit.
The accident at Chernobyl
was the result of a nuclear reactor explosion and core meltdown that occurred
in association with a steam-measuring test and several safety violations and
mistakes. The immediate consequences were 31 deaths, 500 persons hospitalized,
and 116,000 people evacuated. Delayed effects include an increase in thyroid
cancer in exposed children and fetuses.
A boiling-water reactor is a type of light-water
reactor that produces steam to directly power the turbine and produce electricity.
It uses the most common isotope of hydrogen and water is used as a moderator
and as a reactor-core coolant.
Plutonium-239 is produced when a fast-moving neutron hits a nonradioactive
uranium-238 nucleus and is absorbed. The result is a new substance, P-239.
Plutonium-239 is considered dangerous because
it is extremely radioactive and hazardous to human health. Also, because it
can be made into nuclear weapons, it must be transported, processed, and produced
under very close security.
The energy released during the combination of two lightweight atomic
nuclei to form a heavier nucleus is known as nuclear fusion. Fusion is currently
not being used as a source of energy because several technical difficulties
prevent its commercial use. The main technical problem is containment of the
nuclei since their positive charges cause them to repel each other.
The major environmental problems associated with nuclear power is
the disposal of high-level radioactive waste, exposure to radioactivity during
mining, processing, and transportation, and the threat of accidents.
The construction and de-emphasis of nuclear weapons causes the contamination
of production sites and the surrounding lands, the contamination of test sites,
and the problem of storing both new material and waste.
